WO2007069615A1

WO2007069615A1 - Thermally shrinkable void-containing laminate film and thermally shrinkable void-containing film

Info

Publication number: WO2007069615A1
Application number: PCT/JP2006/324781
Authority: WO
Inventors: You Miyashita; Takeyoshi Yamada; Takashi Hiruma; Jun Matsui; Kanako Hayashi; Kazuhisa Miyashita; Jun Takagi
Original assignee: Mitsubishi Plastics, Inc.
Priority date: 2005-12-12
Filing date: 2006-12-12
Publication date: 2007-06-21

Abstract

The object is to provide a thermally shrinkable film which has a low bulk specific gravity, can be separated readily by liquid gravity separation when used as a label for a PET bottle, has high stiffness, breaking resistance, excellent shrinking property and a small natural shrinkage, and can be separated readily by liquid gravity separation. Disclosed is a thermally shrinkable void-containing laminate film which comprises at least two layers comprising a layer (1) and a layer (II). The layer (I) comprises a mixed resin composition which comprises a component (A) comprising a given polylactate resin composition and a component (B) comprising a given polyolefin resin composition, wherein the content of the component (B) is 10 to 90 parts by mass inclusive relative to 100 parts by mass of the component (A). The layer (II) comprises a resin composition comprising mainly the component (A). In the layer (I), the aspect ratio of a dispersion domain comprising the component (B) dispersed in a matrix composed of the component (A) with respect to the direction orthogonal to the main shrinkage direction is 5 to 50 inclusive.

Description

Specification

Heat-shrinkable pore-containing laminated film and heat-shrinkable pore-containing film

[0001] The present invention relates to a heat-shrinkable pore-containing laminated film, a heat-shrinkable pore-containing film, and a molded product, a heat-shrinkable label, and a container using the same. More specifically, the heat shrinkable film, which has reduced environmental impact by reducing the use of petroleum resources, has high rigidity and has pores to reduce bulk specific gravity, making it lightweight, heat insulating, and light-shielding. The present invention relates to a heat-shrinkable pore-containing film, a heat-shrinkable label, a molded product, and a container that exhibit high performance and concealability, and are excellent in printability, rigidity, rupture resistance, and shrinkage properties, and have small natural shrinkage.

Background art

Conventionally, heat-shrinkable films have been used for packaging applications such as containers and for bundling applications. As raw materials for the heat-shrinkable film, polyvinyl chloride, polystyrene, polyester and the like are mainly used. All of these use petroleum resources as raw materials, so if they are used continuously in the future, there is a possibility that they will cause a problem of oil resource depletion. These raw materials also have problems such as generation of harmful gases during combustion after use, combustion calories are too high, damage the combustion furnace, and shorten the life of the furnace.

[0003] As a material for solving these problems, polylactic acid, which is derived from plants and can be industrially produced, has recently attracted attention. In other words, polylactic acid uses corn and other biomass as a raw material, so it is suitable for aiming for a sustainable society. Furthermore, it does not generate harmful gases during combustion, and its combustion calories are low, which can damage the combustion furnace. What! /

[0004] However, when polylactic acid is used as the material for the heat-shrinkable label, it has high rigidity and excellent low-temperature shrinkability, and has the characteristics of natural shrinkage and small size, but there is a problem in fracture resistance. Therefore, it has been difficult to produce a high-quality heat-shrinkable label using polylactic acid alone.

[0005] In order to improve the fracture resistance of polylactic acid, a heat-shrinkable film to which a soft component compatible with polylactic acid is added has also been proposed (see, for example, Patent Document 1). This film can improve the rupture resistance problem to some extent by adding a soft component, but on the other hand, there is a problem that the rigidity is reduced and the natural shrinkage is increased. [0006] On the other hand, when heat-contractable labels are used in PET (polyethylene terephthalate) bottles that are currently consumed, heat-shrinkable labels are used in PET bottles from the viewpoint of recycling used PET bottles. The power should be easily separable. PET bottle force As a method of separating heat-shrinkable labels, liquid specific gravity separation method in which flakes of PET bottles pulverized with heat-shrinkable labels are put into water, and only the PET flakes are submerged in water and recovered. Is used. However, since the bulk specific gravity of the heat-shrinkable label described in Patent Document 1 is greater than 1, the label also sunk in water together with the PET bottle flakes, making it difficult to separate.

[0007] By the way, not only the heat-shrinkable label but also the formation of pores in a molded product using thermoplastic resin reduces the bulk specific gravity of the molded product, thereby reducing the amount of resin used. It is known that environmental loads can be reduced and functions such as light shielding, heat insulation and cushioning can be added. Various methods can be used to form this pore. In the case of a stretched film using thermoplastic resin, it is stretched in at least one direction after adding incompatible components to the thermoplastic resin. Techniques are known.

[0008] For the purpose of reducing the bulk specific gravity of this thermoplastic resin, a method is known in which after adding an incompatible component, the thermoplastic resin is stretched in one direction or more to form voids. Even in a film using polylactic acid-based resin, a film having a reduced bulk specific gravity by stretching after adding an incompatible resin has been reported (for example, see Patent Document 2). However, this film cannot be used as a heat-shrinkable label because it has been biaxially stretched and then heat-treated.

[0009] In addition, a heat-shrinkable film in which a non-compatible resin is added to a polyester-based resin other than polylactic acid and then stretched to form pores has also been proposed (see, for example, Patent Document 3). However, the polyester-based resin used in this heat-shrinkable film has a drawback that it is difficult to form pores at the time of stretching compared to polylactic acid.

[0010] Furthermore, adjusting the isomer ratio of polylactic acid in order to adjust the shrink finish of the polylactic acid-based shrink film is described in Patent Document 4, etc., but it is rigid as a heat-shrinkable film. It does not sufficiently satisfy the shrinkage characteristics, and there is no description about application to a film in which pores are formed. [0011] In addition, recently, heat-shrinkable labels having a light-shielding function have been frequently used for the purpose of protecting the contents of containers from ultraviolet rays and visible light, and accordingly, aroma having a light-shielding function. Many polyester-based shrink labels have been proposed (see Patent Documents 5 and 6)

. However, all of these heat-shrinkable films use aromatic polyester, which is a petroleum-derived rosin, and therefore have a problem of environmental impact and are more vacant when stretch-molded than a polylactic acid-based rosin. There were difficulties and disadvantages in forming holes.

[0012] Further, a heat-shrinkable holey film in which polylactic acid is mixed with an incompatible resin is proposed.

(See Patent Document 7). However, this film was able to form sufficient pores, but did not have sufficient light shielding function.

Patent Document 1: Japanese Patent Application Laid-Open No. 2003-119367

Patent Document 2: Japanese Patent Laid-Open No. 2002-146071

Patent Document 3: Japanese Patent Laid-Open No. 2003-321562

Patent Document 4: Japanese Patent Laid-Open No. 2001-011214

Patent Document 5: Japanese Patent Application Laid-Open No. 2003-236930

Patent Document 6: Japanese Unexamined Patent Application Publication No. 2004-114498

Patent Document 7: Japanese Unexamined Patent Application Publication No. 2006-045296

Disclosure of the invention

Problems to be solved by the invention

[0014] The present invention has been made in view of the above-mentioned problems, and the problem of the present invention is that it is used as a label for PET bottles having a low bulk specific gravity using a polylactic acid-based resin derived from plants. Another object is to provide a heat-shrinkable film that can be easily separated by liquid specific gravity, has high rigidity, rupture resistance, and shrinkage characteristics, has small natural shrinkage, and can be easily separated by liquid specific gravity.

Another object of the present invention is to provide a heat-shrinkable label, a molded product and a container using the film suitable for applications such as shrink wrapping, shrink-bound wrapping and shrinkage labels. Means to do

[0016] The present invention includes the following component (A) and component (B), and the content of component (B) is the above ( The component (I) is composed of a mixed resin composition that is 5 parts by weight or more and 90 parts by weight or less with respect to 100 parts by weight of the component (A) and the component (A) as a main component. C) component, and when it contains (C) component, it is composed of a mixed resin composition whose content of (C) component is 5 parts by weight or more and 50 parts by weight or less with respect to 100 parts by weight of component (A) The (I) layer has at least two layers and is stretched in at least one axial direction, and in the (I) layer, dispersed in a matrix having (A) component force, Including a laminated film having an aspect ratio of 5 to 50 in the direction perpendicular to the main shrinkage direction of the dispersion domain, or the following (A) component, (B) component and (C) component, and (A) component 100 mass The content of component (B) is not less than 5 parts by mass and not more than 90 parts by mass, and the content of component (C) is not less than 10 parts by mass and not more than 80 parts by mass An unstretched film made of a synthetic resin composition or having at least one mixed resin layer and stretched at least uniaxially. When immersed in warm water at 80 ° C for 10 seconds, The invention relates to a heat-shrinkable laminated film or single-layer film having pores having a heat shrinkage rate of 20% or more.

Component (A): Polylactic acid based resin composition comprising a copolymer of D lactic acid and L lactic acid as a main component

Component (B): Polyolefin with a storage modulus at 80 ° C of 0.25 GPa or more 2. OOGPa or less when measured at a vibration frequency of 10 Hz and a strain of 0.1%, incompatible with component (A) -Based rosin composition.

Component (C): Aliphatic polyester other than polylactic acid-based resin, aromatic aliphatic polyester, copolymer of diol, dicarboxylic acid and polylactic acid-based resin, core-shell structure type rubber, ethylene-butyl acetate copolymer , Ethylene (meth) acrylate copolymer, ethylene- (meth) acrylic acid copolymer, ethylene (meth) methyl acrylate copolymer, and styrene elastomer Or a mixture of rosin and soft ingredients.

In the above, “(meth) acryl” means to include both “acryl” and “methacryl”. For example, “(meth) acrylic acid” means acrylic acid and methacrylic acid. The same applies in the description.) O

The invention's effect [0018] The laminated film and the single-layer film of the present invention are prepared by mixing a predetermined polylactic acid-based resin composition (component (A)) and a polyolefin-based resin composition (component (B)) at a predetermined ratio. In addition, the aspect ratio of the component (B) in the component (A) is adjusted in this layer, so that the resulting heat-shrinkable pore-containing film has excellent rigidity and fracture resistance. In addition, the heat shrinkage characteristics can be imparted and the natural shrinkage rate can be reduced. In addition, since the film of the present invention is mainly composed of a lactic acid-based rosin composition, it is useful in promoting the use of biomass and building a recycling society.

Furthermore, the laminated film and the single layer film of the present invention are obtained by laminating the (I) layer containing pores and the (、) layer having a smooth surface. Excellent bag sealability and design. Furthermore, since the film of the present invention contains pores, it has excellent heat insulating properties, light shielding properties, and cushioning properties.

[0020] Further, since the laminated film of the present invention has a bulk specific gravity of 0.50 or more and less than 1.00, it can be separated by a liquid specific gravity method from a plastic for containers having a specific gravity of PET or more of 1.0 or more. Therefore, it is highly recyclable.

[0021] Furthermore, by using the laminated film or single layer film of the present invention, a molded product suitable for applications such as shrink wrapping, shrink tying wrapping, and shrink label having excellent shrink finish and light shielding properties, heat A shrinkable label can be provided.

[0022] Furthermore, it can be fixed in a desired position regardless of the shape of the wearing object, and has a beautiful appearance with no shading, abnormal occurrence such as avatar, insufficient shrinkage, etc., and a light shielding property. A container equipped with a molded article or a heat-shrinkable label can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

[0023] This invention relates to a laminated film or a single layer film containing the following component (A), component (B), and optionally component (C) and component (D). In the following, components (A) to (D) will be described first.

In the present specification, “contains as a main component” is intended to allow other components to be included within a range that does not interfere with the operation and effect of the resin constituting each layer. Furthermore, this term does not limit the specific content, but it is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more of the total constituents of each layer. It is a component occupying a range of mass% or less.

[0024] <(Eight) component>

The component (A) refers to a polylactic acid-based resin composition mainly composed of a copolymer of D-lactic acid and L-lactic acid.

[0025] Specifically, the component (A) is a copolymer of lactic acid homopolymer, lactic acid and α-hydroxycarboxylic acid other than lactic acid, diol component and dicarboxylic acid component, or both. It also includes a lactic acid-based copolymer whose main component is a coalescence.

[0026] Here, lactic acid refers to both D lactic acid and L lactic acid. Examples of the lactic acid homopolymer include, for example, poly (D lactic acid), which is a homopolymer of D lactic acid, and L lactic acid alone. Examples thereof include poly (L-lactic acid) which is a polymer, poly (DL-lactic acid) which also has a copolymer power of L-lactic acid and D-lactic acid, and a mixture thereof. Hereinafter, these lactic acid-only polymers are referred to as lactic acid-based rosins.

[0027] As a method for polymerizing the lactic acid-based rosin, a known method such as a condensation polymerization method or a ring-opening polymerization method may be employed. For example, in the case of the condensation polymerization method, D-lactic acid, L-lactic acid, or a mixture thereof can be directly subjected to dehydration condensation polymerization to obtain a polylactic acid-based resin having an arbitrary composition. In the ring-opening polymerization method, lactide, which is a cyclic dimer of lactic acid, is subjected to ring-opening polymerization in the presence of a predetermined catalyst while using a polymerization regulator or the like, if necessary. It is possible to obtain a polylactic acid-based resin having the same. The lactide includes L-lactide, which is a dimer of L-lactic acid, D-lactide, which is a dimer of D-lactic acid, and DL lactide, which is a dimer of D-lactic acid and L-lactic acid. By mixing and polymerizing according to the above, it is possible to obtain a polylactic acid-based resin having an arbitrary composition and crystallinity.

[0028] By the way, a lactic acid copolymer mainly composed of a copolymer of lactic acid and an ex-hydroxycarboxylic acid other than lactic acid, a diol component and a dicarboxylic acid component, or both of them is used as the lactic acid used. Either D-lactic acid or only lactic acid, or both D-lactic acid and L-lactic acid may be used.

[0029] When the lactic acid copolymer is used, the copolymerization ratio of the constituent components is not particularly limited. However, the higher the ratio of lactic acid, the less consumption of petroleum resources, which is preferable as described later. It is preferable to copolymerize at a rate not exceeding the Vicat soft spot range. [0030] Specifically, the copolymerization ratio of lactic acid and a copolymer of a-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid is expressed by mass ratio of lactic acid-hydroxycarboxylic acid, fatty acid. Group diol or aliphatic dicarboxylic acid = 100ZO to 95Ζ5, preferably 90Z10 to 10Ζ90, more preferably 80Ζ20 to 20Ζ80, and most preferably 30,700 to 70Ζ30. When the copolymerization ratio is within the above range, a film having a good balance of physical properties such as rigidity, transparency and impact resistance can be obtained.

[0031] The lactic acid-based rosin and the lactic acid-based copolymer may be used alone or in combination.

[0032] In addition, when a ring-opening polymerization method (lactide method) is used for the production of the lactic acid-based rosin, lactide, which is a cyclic dimer of lactic acid, is used as necessary using a polymerization regulator or the like. A ring-opening polymerization can be carried out in the presence of a predetermined catalyst to obtain a lactic acid series resin having an arbitrary composition. Examples of the lactide to be used include L-lactide, which is a dimer of L lactic acid, D lactide, which is a dimer of D lactic acid, and DL lactide, which is a dimer of D lactic acid and L lactic acid. By mixing and polymerizing these as necessary, the above-mentioned lactic acid-based resin having any composition and crystallinity can be obtained.

[0033] The a-hydroxycarboxylic acid as a monomer used in the production of the lactic acid copolymer includes glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-1-n-butyric acid, 2-hydroxy Examples include bifunctional aliphatic hydroxycarboxylic acids such as 3,3 dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2-hydroxycaproic acid, and latatones such as prolatatone, petit-mouthed ratataton, and valerolatataton.

[0034] Examples of the diol component that is a monomer used in the production of the lactic acid-based copolymer include ethylene glycol, propylene glycol, 1,4 butanediol, 1,4 cyclohexanedimethanol, and the like. . Examples of the dicarboxylic acid component include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

[0035] The polylactic acid-based resin composition (A) may contain a small amount of another copolymer component in order to improve heat resistance. Examples of such copolymer components include aromatic carboxylic acids such as terephthalic acid, and aromatic dials such as bisphenol A ethylene oxide adducts. Furthermore, the polylactic acid-based resin composition (A) has an increased molecular weight. For this purpose, a small amount of a chain extender such as a diisocyanate compound, an epoxy compound or an acid anhydride may be contained.

[0036] The Vicat softness point of the polylactic acid-based resin composition (A) is preferably 50 ° C or higher and 55 ° C or higher. If the Vicat soft spot is 50 ° C or higher, the resulting heat-shrinkable pore-containing film can suppress spontaneous shrinkage even if it is left at a temperature slightly higher than room temperature, for example, in the summer, but 50 ° C If it is less than this, this natural shrinkage may not be suppressed. On the other hand, the Vicat soft spot is preferably 95 ° C or less and preferably 85 ° C or less. If it exceeds 95 ° C, it will be difficult to perform low-temperature stretching when the film is stretched, and it will be difficult to give good shrinkage characteristics to the resulting film.

[0037] The mass average molecular weight of the polylactic acid-based resin composition (A) is preferably 20,000 or more, more than 40,000 force S, and even more preferably 50,000 or more, It is more preferable that it is 100,000 or more. If the mass average molecular weight is 20,000 or more, it is preferable that defects such as inferior mechanical strength are difficult to occur, an appropriate cohesive strength of the resin is obtained, and the film has insufficient strength and is brittle. O On the other hand, it should be 400,000 or less, preferably 350,000 or less, and more preferably 250,000 or less. If it is 400,000 or less, the melt viscosity becomes too high, and it is difficult to cause problems such as a decrease in molding caloric properties.

[0038] Typical examples of such a resin composition that can be used as the polylactic acid-based resin composition (A) include "Lacy" series manufactured by Mitsui Chemicals, Inc., "Nat" manufactured by Nature Works LLC. The “ure Works” series and the like are commercially available.

[0039] The component (A) can also contain a small amount of other copolymerization components for the purpose of improving heat resistance. Examples of such a copolymer component include aromatic carboxylic acids such as terephthalic acid, and aromatic diols such as ethylene oxide adducts of bisphenol A. Furthermore, the component A can contain a small amount of a chain extender such as a diisocyanate compound, an epoxy compound, an acid anhydride, etc. for the purpose of increasing the molecular weight.

[0040] <Component (B)>

The component (B) is a polyolefin-based soot that is incompatible with the component (A) and has predetermined characteristics. Refers to a fat composition. Here, “incompatible” means that when the mixed resin composition of the component (A) and the component (B) is observed using an optical device such as an electron microscope, the component (A) In this state, the component (B) forms a domain having an average diameter of 0.1 μm or more.

[0041] Examples of the resin constituting the component (B) include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene and other polyethylene-based resins, highly crystalline homopolypropylene, random polypropylene, and the like. Polypropylene resin, polymethyl terpene, or mixed resin of these, and high crystalline polypropylene is preferable. These coffins can be used alone or in admixture of two or more.

[0042] The resin constituting the component (B) is more specifically a polyethylene-based resin having the trade names "Novatech HD, LD, LLJ" Kernel "" Toughmer A, PJ (manufactured by Nippon Polyethylene Co., Ltd.) ) "Suntech HD, LDJ (Asahi Kasei Life & Living Co., Ltd.)", "HIZEX" "ULTZEX" "E VOLUEJ (Mitsui Chemicals Co., Ltd.)", "More Tech" (Idemitsu Kosan Co., Ltd.), "UBE Polyethylene "UMERIT" (manufactured by Ube Industries Co., Ltd.), "NUC polyethylene" "Nacflex" (manufactured by Nippon Car Co., Ltd.), "Engage" (manufactured by Dow Chemical Co., Ltd.) . Polypropylene-based resins include the product names “NOVATEC PP”, “WINTEC”, “Toughmer XR” (manufactured by Nippon Polypro), “Mitsui Polypro” (manufactured by Mitsui Chemicals), “Sumitomo Noblen”, “ "Tufselen", "Exelen EPX" (manufactured by Sumitomo Chemical Co., Ltd.), "IDEMITSU PP", "IDEMITSU TPO" (manufactured by Idemitsu Kosan Co., Ltd.), "Adflex", "Adsyl" (manufactured by Sanalomar Co., Ltd.) It has been. As a polymethylpentene resin, “TPX” (manufactured by Mitsui Engineering Co., Ltd.) is commercially available. These can be used alone or in admixture of two or more.

The density of [0043] the (beta) component, 0. 50 g / cm ³ or higher, preferably 0. 65 g / cm ³ or more, more preferably 0. 80 g / cm ³ or more, 1. 00g / cm ³ or less preferably 0. 96 g / cm ³ hereinafter, still more preferably in the range of 0. 92 g / cm ³ or less. If the density is 1.00 g Zcm ³ or less, the effect of reducing the specific gravity of the entire film is great. If the density is 0.50 g Zcm ³ or more, problems such as lack of rigidity and difficulty in forming pores during stretching occur. It is preferable.

[0044] Since the component (B) has a specific gravity smaller than that of the polylactic acid-based resin composition used as the component (A), the film containing the mixed resin composition of the component (A) and the component (B) is , (A) component alone The specific gravity can be further reduced as compared with the case of the film. Furthermore, the bulk specific gravity can be further reduced by the voids generated during stretching due to the presence of the component (1).

[0045] The component (B) has a storage elastic modulus at 80 ° C when measured at a frequency of 10 Hz and a strain of 0.1%, of 0.25 GPa or more, preferably 0.40 GPa or more, and 2. OOGPa Below, preferably 1.50 GPa or less. If the storage elastic modulus is 0.25 GPa or more, pores can be imparted to the film in the stretching step described below, and if the storage elastic modulus is 2. OOG Pa or less, the desired crystallinity is obtained. In addition, since the specific gravity can be made relatively small, it is easy to obtain a film having a desired bulk specific gravity.

[0046] The component (B) preferably has a melt flow rate (hereinafter abbreviated as "MFR") measured based on JIS K7211 of 0.5 gZlO or more. 1. OgZlO More preferably, it is more than minutes. The MFR is preferably 50 gZlO or less, more preferably 35 gZlO or less, and even more preferably 20 gZlO or less. If the MFR of component (B) is 1. OgZlO or more, when the sea-island structure is formed on the film, the size of the dispersion domain becomes too large, or the dispersion state is poor and vacancies are not easily generated. This is suitable for preventing problems such as snoring. On the other hand, if the MFR of the component (B) is 50 gZlO or less, the size of the dispersed domain is reduced when the sea-island structure is formed, the strength of the domain itself is reduced, and the fracture resistance at low temperatures is reduced. It is suitable without causing problems such as insufficient application.

[0047] Since the component (B) is incompatible with the component (A) and the component (C) described later, the (I) layer in which both components are mixed has a sea-island structure. As will be described later, in the (I) layer of the film of the present invention, the (A) component is present more than the (B) component, so the (A) component and (C) component form a sea part, that is, a matrix. , (B) component forms an island portion, that is, a dispersion domain. Details will be described later.

[0048] <(C) component>

The component (C) refers to a soft component that is a rubber component exhibiting rubber elasticity other than the component (A). For the purpose of improving the metaimpact of the film of the present invention, it can be added within a range not impairing the rigidity of the film of the present invention. [0049] Specifically, as the component (C), a lactic acid polymer having a Tg of 0 ° C or less other than the polylactic acid resin, an aliphatic polyester other than the polylactic acid resin, and an aromatic aliphatic polyester , Copolymer of diol, dicarboxylic acid and lactic acid-based resin, core-shell structure rubber, ethylene acetate butyl copolymer (EVA), ethylene acrylate ethyl acrylate copolymer (EEA), ethylene (meth) acrylic Acid copolymer (EAA, EMA), ethylene (meth) methyl acrylate copolymer (EMMA, etc.), styrene isoprene copolymer (SIS), styrene butadiene copolymer (SBS), styrene ethylene butylene copolymer ( SEBS), styrene-based elastomers such as acid-modified SEBS, and the like. Among them, aliphatic polyesters other than polylactic acid-based resin, aromatic aliphatic polyester, diol, dicarboxylic acid, and lactic acid-based resin Copolymers, core-shell structure type rubbers, and ethylene-vinyl acetate copolymer (EVA) or the like is preferably used.

[0050] The lactic acid-based copolymer having a Tg of 0 ° C or lower other than the polylactic acid-based resin is a copolymer of lactic acid and an ex-hydroxycarboxylic acid component or a dicarboxylic acid component and a diol component, Tg is 0 ° C or less. Examples of the a-hydroxycarboxylic acid component that forms a lactic acid copolymer having a Tg of 0 ° C. or less include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2 hydroxy-n-butyric acid, 2 hydroxy3, 3 Bifunctional aliphatic hydroxycarboxylic acids such as dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, and 2-hydroxycaproic acid, and lactones such as force prolatatone, petit-mouthed ratataton, and valerolatatone. Examples of the diol component that forms the lactic acid copolymer having a Tg of 0 ° C. or lower include ethylene glycol, propylene glycol, 1,4 butanediol, and 1,4-cyclohexanedimethanol. It is done. Examples of the dicarboxylic acid component include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

[0051] Examples of commercially available lactic acid-based copolymers having a TgO ° C or lower include, for example, the product name “Bramate” (manufactured by Dainippon Ink & Chemicals) and the product name “GS-PLA” (Mitsubishi). Chemical Co., Ltd.).

[0052] Examples of the aliphatic polyester resin other than the polylactic acid-based resin include, for example, an a-hydroxycarboxylic acid homopolymer excluding lactic acid, an aliphatic diol and an aliphatic dicarboxylic acid. Aliphatic polyester resin except PLA polyester such as aliphatic polyester obtained by condensation, aliphatic polyester obtained by ring-opening polymerization of cyclic ratatones, and synthetic aliphatic polyester.

Here, α-hydroxycarboxylic acid residues include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy η-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid. 2 Residues induced by bifunctional aliphatic hydroxycarboxylic acids such as hydroxycaproic acid, and residues induced by ratatones such as force prolatatone, petit-mouthed rataton and normouthed rataton.

[0054] Specific examples of the aliphatic polyester obtained by condensing an aliphatic diol and an aliphatic dicarboxylic acid include ethylene glycol, 1,4 butanediol, hexanediol, octanediol, cyclopentanediol, Aliphatic diols such as cyclohexanediol, 1,4-cyclohexanedimethanol, or anhydrides and derivatives thereof, and aliphatic dicarboxylic acids such as succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid Examples include one obtained by condensation polymerization of one or more of each of acids or their anhydrides and derivatives. At this time, if desired, the desired polymer can be obtained by jumping up with isocyanate compound or the like.

[0055] In addition, as the aliphatic polyester obtained by ring-opening polymerization of the above-mentioned cyclic ratatones, one or more kinds selected from ε-force prolatatatone, δ-valerolataton, 13-methyl-δ-valerolataton, etc. are selected as cyclic monomers. Polymerized ones can be mentioned. Furthermore, examples of the synthetic aliphatic polyester include a copolymer of a cyclic acid anhydride such as succinic anhydride and an oxysilane such as ethylene oxide propylene oxide.

[0056] Examples of commercially available aliphatic polyester resin other than the polylactic acid resin include the trade name "Pionore" (manufactured by Showa Polymer Co., Ltd.), the trade name "Cell Green" ( Daicel Kagaku Kogyo Co., Ltd.) and the trade name “Tone Polymer” (Union Carbide Japan Co., Ltd.).

[0057] The aromatic aliphatic polyester resin used as the component (C) includes an aliphatic diol or a derivative thereof, an aliphatic dicarboxylic acid or a derivative thereof, and an aromatic dicarboxylic acid or a derivative thereof. Condensation polymerized. In addition, the aromatic polyester Lubricant is a product obtained by condensation polymerization of an aromatic dicarboxylic acid or a derivative thereof and an aromatic dicarboxylic acid or a derivative thereof. Among these, examples of aromatic diols or derivatives thereof include bisphenol A ethylene oxide adducts. In addition, examples of aromatic dicarboxylic acids or derivatives thereof include terephthalic acid, isophthalic acid, orthophthalic acid, 2,4 naphthalene dicarboxylic acid, paraphenol dicarboxylic acid, and the like. In this condensation polymerization, a desired polymer can be obtained by extending the chain with an isocyanate compound or the like as necessary.

[0058] Commercially available examples of the above aromatic aliphatic polyester rosin include the product name "Easter Bio" (Eastman Chemicals) and the product name "Ecoflex" (BAS F) ).

[0059] The mass (weight) average molecular weight of the lactic acid copolymer of TgO ° C or less, the aliphatic polyester resin, and the aliphatic aromatic polyester resin used as the component (C) is 50,000 or more. It is more preferable that it is 100,000 or more. If it is 50,000 or more, it is preferable that problems such as inferior mechanical strength hardly occur. On the other hand, the mass (weight) average molecular weight is preferably 400,000 or less, more preferably 250,000 or less! /. If it is 400,000 or less, it is preferable that problems such as a decrease in molding processability due to excessive increase in melt viscosity are difficult to occur.

[0060] The above-mentioned copolymer of diol, dicarboxylic acid, and lactic acid-based resin is a lactic acid-based copolymer, and preferably has a Tg of 0 ° C or lower. Examples of this include a trade name “Bramate” (Dainippon Ink Chemical Co., Ltd.), a trade name “GS-PLA” (Mitsubishi Chemical Corporation), and the like.

[0061] The core-shell structure rubber used as the component (C) includes gen-based core-shell type polymers such as monobutadiene methacrylate methacrylate and acrylonitrile butadiene styrene copolymer, styrene acrylonitrile methacrylate copolymer Examples thereof include acrylic core-shell type polymers such as coalescence, silicone-based core-shell type copolymers such as silicone-methacrylic acid-methyl methacrylic acid copolymer, and silicone-one-methacrylic acid-acrylonitrile-styrene copolymer. Among these, silicone-methyl methacrylate is excellent in compatibility with the component (A), and can balance the impact resistance and transparency of the film. A phosphoric acid copolymer is more preferably used.

[0062] The mass (weight) average molecular weight of the shell portion of the core-shell structure rubber is preferably 10,000 or more, and more preferably 50,000 or more. If it is 10,000 or more, it is preferable that problems such as inferior mechanical strength hardly occur. On the other hand, the weight average molecular weight is preferably 1,500,000 or less, and more preferably 100,000 or less! / ヽ. If it is 1,500,000 or less, it is preferable that the melt viscosity becomes too high and problems such as deterioration of molding processability are difficult to occur.

[0063] Commercially available examples of such core-shell structured rubber include "Metablene C, S, E, Wj (Mitsubishi Rayon Co., Ltd.)", "Kane Ace" (Kaneki Co., Ltd.), etc. Is mentioned.

[0064] Further, ethylene acetate butyl copolymer (EVA), ethylene (meth) acrylic acid copolymer (EAA), ethylene (meth) acrylic acid ester copolymer (EMA), used as the component (C), The ethylene methyl (meth) acrylate copolymer (EMMA) has a comonomer content other than ethylene of 20% by mass or more, preferably 40% by mass, 90% by mass or less, preferably 80% by mass or less. Those are preferably used. If the comonomer content other than ethylene is 20% by mass or more, an effect on the fracture resistance of the film can be sufficiently obtained, and transparency can be maintained, which is preferable. On the other hand, if the content of monomers other than ethylene is 80% by mass or less, the rigidity and heat resistance of the entire film can be maintained well, which is preferable. Among these, ethylene acetate butyl copolymer (EVA) is more preferably used.

[0065] The melt flow rate (MFR) of EVA, EAA, and EMMA is not particularly limited, but usually MFR (value at JIS K7210, temperature: 190 ° C, load: 21.18N) Is 0.5 gZlO min or more, preferably 1. OgZlO min or more, 15 gZl0 min or less, preferably 1 OgZlO min or less.

[0066] Examples of commercially available ethylene vinyl acetate copolymers (EVA) include EVAFLEXJ (Mitsui DuPont Polychemical Co., Ltd.), Novatec EVA (Mitsubishi Chemical Co., Ltd.), Ebaslene (Dainippon Ink Chemical Co., Ltd.), Evaate (Sumitomo Chemical Co., Ltd.), Soabrene (Nippon Gosei Co., Ltd.), ethylene-acrylic acid copolymer (EAA) "Novatech EAA" (Mitsubishi Chemical Co., Ltd.), Ethylene acrylate copolymer (E MA) and ethylene- (meth) acrylic acid copolymer (EMA) are “NOAFLOY AC” (Mitsui DuPont Polychemical Co., Ltd.), and ethylene methyl (meth) acrylic acid copolymer (EMMA) is “ACLIFT (Sumitomo Chemical Co., Ltd.).

[0067] The ethylene vinyl acetate copolymer (EVA), ethylene (meth) acrylic acid copolymer (EAA), ethylene (meth) acrylic acid ester copolymer (EMA), ethylene-methyl (meth) acrylic acid ester copolymer As the polymer (EMMA), a comonomer content other than ethylene is preferably 10% by mass or more, preferably 40% by mass or more and 90% by mass or less, preferably 80% by mass or less. . By making it within the above range, it becomes possible to prevent the deterioration of the solvent sealing property while giving sufficient softness to the layer (II) described later.

[0068] The styrene-isoprene copolymer (SIS), styrene-butadiene copolymer (SBS), styrene ethylene-butylene copolymer (SEBS), styrene-based elastomers such as acid-modified SEBS, etc. The content is preferably 10 to 50 mass, more preferably 20 to 40 mass. By setting the amount within the above range, it becomes possible to impart sufficient softness to the layer (ii) described later.

[0069] As the component (C), the storage elastic modulus at 23 ° C when measured under conditions of a vibration frequency of 10 Hz and a strain of 0.1% is 1 X 10 ⁹ Pa or less, more preferably 5 X 10 ⁸ A resin composition having a Pa or lower is used. If the storage elastic modulus is 1 × 10 ⁹ Pa or less, it becomes possible to suppress delamination during sealing without impairing the properties of the heat-shrinkable film due to the addition.

[0070] <(D) component>

The component (D) refers to a predetermined filler. This component (D) may be a misaligned filler of inorganic fillers and organic fillers as long as it can impart light-shielding properties to the film.

[0071] Examples of the inorganic filler include calcium carbonate, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, aluminum hydroxide, zinc oxide, magnesium hydroxide. , Calcium oxide, magnesium oxide, titanium oxide, alumina, my strength, asbestos powder, shirasu balloon, zeolite, silicate white Examples of the material include calcium carbonate, talc, clay, silica, diatomaceous earth, and barium sulfate. Examples of the organic filler include cellulose powders such as wood powder and pulp powder. These may be used alone or as a mixture of two or more.

[0072] The component (D) is a material having a large refractive index difference from the component (A) as the base resin constituting the film, that is, an inorganic filler having a large refractive index. Is preferred. Specifically, it is preferable to use calcium carbonate, barium sulfate, acid titanium or acid zinc having a refractive index of 1.6 or more, and among these, it is more preferable to use acid titanium. . By using titanium oxide, it absorbs the wavelength in the ultraviolet region of 280 to 380 nm, which deteriorates the contents, so it can give the film light-shielding properties with a small amount of filling, and it is thin-walled. But you can get that effect.

[0073] Examples of the titanium oxides include crystalline titanium oxides such as anatase type titanium oxide and rutile type titanium oxide. From the viewpoint of increasing the difference in refractive index from the base resin, it is preferable to use an acid-titanium having a refractive index of 2.7 or more. For example, a crystal form of rutile-type acid-titanium is used. It is preferable to use it.

[0074] Among the titanium oxides, high-purity acid titanium can be used to minimize the yellowness of the appearance. High purity titanium oxide is a titanium oxide that has a low light absorption ability for visible light, and has a low content of coloring elements such as vanadium, iron, niobium, copper, manganese, etc. A titanium oxide having a vanadium content of 5 ppm or less, preferably 3 ppm or less, and more preferably 2 ppm or less is referred to as high-purity acid titanium. From the viewpoint of reducing the light absorption ability of high-purity titanium oxide, it is preferable to reduce other coloring elements such as iron, niobium, copper, and manganese contained in titanium oxide.

[0075] In the film of the present invention, titanium oxide and other fillers can be used in combination. Also,

In order to improve the dispersibility of the component (D) in the resin (that is, the component (A) and the component (B)), the surface of the component (D) is a silicone compound, polyhydric alcohol compound, amine compound. You may use what surface-treated with a compound, a fatty acid, fatty acid ester, etc.

[0076] Examples of the surface treatment agent include at least one inorganic compound selected from the group consisting of alumina, silica, zirconia, and the like, a siloxane compound, a silane coupling agent, and a polysiloxane. Group power of all and polyethylene glycol power At least one selected organic compound can be used. These inorganic compounds and organic compounds may be used in combination.

[0077] The size of the component (D) used in the present invention is such that when titanium oxide is used, the particle diameter is 0.1 μm or more in terms of a circular equivalent diameter, preferably 0.2 μm or more. Yes, 1 μm or less, preferably ί or 0.5 μm or less. If the particle diameter of titanium oxide is equivalent to an equivalent circle diameter of 0 .: L m or more, the dispersibility of the component (A) or the component (A) and the component (B) in the mixed resin is good, and the Rum can be obtained. If the particle diameter of titanium oxide is equivalent to a circle equivalent l / zm or less, the interface between component (A) or a mixed resin of component (A) and component (B) and titanium oxide is formed densely. Therefore, the light shielding property can be further improved.

<Heat-shrinkable pore-containing laminated film and heat-shrinkable pore-containing film that are useful in the present invention>

Next, a heat-shrinkable pore-containing laminated film according to the present invention (hereinafter referred to as “first pore-containing film”) and a heat-shrinkable pore-containing film (hereinafter referred to as “second pore-containing film”). Will be described.).

[0079] <First pore-containing film>

The first pore-containing film is composed of a (I) layer containing the component (A) and the component (B) in a predetermined ratio, and a resin composition containing the component (A) as a main component. It is a film stretched in at least a uniaxial direction and having at least two layers (II).

[0080] [(1) layer]

(mixing ratio)

The mixed resin composition in the (I) layer is 100 parts by mass of the component (A), and the component (B) is 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 20 parts by mass or more. Therefore, it is formed by mixing an amount of 90 parts by mass or less, preferably 80 parts by mass or less.

[0081] In the layer (I), the rosin composition in which the component (A) and the component (B) are mixed is as described above.

Since (A) component is contained more than (B) component, (A) component forms a matrix and (B) component forms a dispersion domain. Therefore, layer (I) forms a sea-island structure and can be stretched to cause separation at the interface between the matrix and the dispersed domain, thereby forming pores. The By changing the copolymer ratio (DZL ratio) of the polylactic acid-based resin composition to be used, the void formation / shrinkage characteristics can be adjusted to the desired range.

[0082] In particular, when the content of the component (B) is 5 parts by mass or more, (I) the pores can be formed in the layer, and the bulk specific gravity of the stretched film is suppressed to less than 1.0. be able to. On the other hand, if the content of the component (B) is 90 parts by mass or less, a sea-island structure can be formed in the layer (I), and a film having good mechanical properties and fracture resistance can be obtained.

[0083] (DZL ratio)

In the layer (I), when the component (A) contains both D-lactic acid and L-lactic acid as lactic acid, the shrinkage unevenness can be suppressed more than that containing only one of the lactic acids. This is preferable. That is, a homopolymer having a constitutional ratio (DZL ratio) of D lactic acid and L lactic acid of 100ZO or OZ 100 exhibits very high crystallinity and tends to have excellent heat resistance and mechanical properties with a high melting point. However, when it is used as a heat-shrinkable film, it usually involves printing and a bag making process using a solvent, so that the crystallinity of the component material itself should be lowered moderately in order to improve printability and solvent sealability. Is required. Further, when the crystallinity is excessively high, orientational crystallization proceeds at the time of stretching, and the film shrinkage property at the time of heating tends to be reduced, and a film that suppresses crystallization by adjusting stretching conditions, etc. In the future, crystallization may proceed before shrinkage due to heating during heat shrinkage, and as a result, there is a risk that shrinkage may occur or shrinkage may be insufficient. On the other hand, in the case of a copolymer of DL lactic acid, it is known that the crystallinity decreases as the proportion of the optical isomer increases. Accordingly, when using a polylactic acid-based resin composition as a heat-shrinkable film, it is preferable to adjust its crystallinity by appropriately adjusting the copolymerization ratio of the DL lactic acid copolymer.

[0084] By the way, as a method for adjusting the D-form and L-form, two or more types of DL lactic acid copolymers having different constituent ratios of D-lactic acid and L-lactic acid are prepared by copolymerization. It can also be adjusted by blending.

[0085] The DZL ratio is preferably L lactic acid ZD lactic acid = 99Zl to 90ZlO, or 1Z99 to 10/90, preferably 97Ζ3 to 93Ζ7, or 3/97 to 7/93. It is preferable that it is the range of these. If the DZL ratio is within the above range, hole forming will be described later. In the process, sufficient pore formation is caused, and a film having a desired bulk specific gravity can be obtained, shrinkage unevenness can be suppressed, and a film having sufficient shrinkage characteristics can be easily obtained.

[0086] (Other additives)

In the layer (I), in addition to the mixed resin composition in which the component (A) and the component (B) are mixed, if necessary, the plasticizer and the heat stable are within the range not impairing the effects of the present invention. Additives such as additives, antioxidants, UV absorbers, light stabilizers, pigments, colorants, lubricants, nucleating agents, hydrolysis inhibitors and the like can be included. In that case, the additive may be contained in an amount of 10 parts by mass or less, preferably 5 parts by mass or less, based on the mass of the mixed resin composition.

[0087] Further, in the layer (I), in addition to the mixed resin composition, if necessary, for the purpose of further improving impact resistance and cold resistance within a range not impairing the effects of the present invention, Glass transition temperature (Tg) of aliphatic polyester resin, aromatic polyester resin, core shell structure rubber, ethylene vinyl acetate copolymer (EVA), etc., 100 parts by mass of polylactic acid resin May be contained in the range of 70 parts by mass or less.

[0088] [(II) layer]

(DZL ratio)

In the layer (ii), the DZL ratio of the component (A) is different from the component (A) used in the layer (I). That is, in the layer (ii), it is important that the DZL ratio of the component (A) is in the range of 6Z94 to 15Z85, or in the range of 94Z6 to 85Z15, and in the range of 7/93 to 12/88, or 93Z7. It is preferably in the range of ~ 88Z12.

[0089] If the DZL ratio is within the above range, the degree of crystallization is suppressed to an appropriate range, and the occurrence of defects such as shrinkage unevenness due to crystallization can be suppressed. Therefore, ink adhesion and seal strength can be improved. On the other hand, if the DZL ratio exceeds the above range, the rupture resistance of the film may be extremely lowered.

[0090] (Constituent components of (Π) layer (only for component (A)))

As described above, the layer (II) is composed of a resin composition containing the component (A) as a main component. In addition, (ii) layer insulation improves interlaminar adhesion and reduces bulk specific gravity as long as it does not impair various properties required for the surface layer, such as printability, solvent sealability, and adhesion resistance. For the purpose Thermoplastic resin other than the relactic acid-based resin composition can be included. Examples of thermoplastic resins other than polylactic acid-based resin compositions include polyolefin resin, polystyrene resin, acrylic resin, amide resin, aliphatic and Z or aromatic polyester resin Are listed.

[0091] The first pore-containing film has, in addition to the (I) layer containing pores, a (Π) layer containing no pores or having a low pore content. By disposing the (i) layer in the (I) layer, it is possible to improve printability, solvent sealability, and the like. Further, in the (I) layer and the (i) layer, by changing the copolymer ratio of the polylactic acid-based resin composition to be used, the void formation / shrinkage characteristics can be favored and adjusted to the range.

[0092] ((Π) component of the layer (when the component (C) is included))

The layer (ii) may contain the component (C) in addition to the component (A). By mixing this component (C), the difference in elastic modulus with the layer (I) can be reduced, and as a result, the film's stiffness can be reduced. In addition, an improvement in interlayer adhesion strength between the (I) layer and the (i) layer can be expected. In addition, further improvement in fracture resistance and shrinkage finish can be expected.

[0093] The component (A) used in the layer (A) is a soft component, although a polylactic acid-based rosin composition having a D ZL ratio within a predetermined range is selected in order to improve shrinkage finish. By mixing the component (C), the adhesion between the (I) layer and the (i) layer is improved, and the shrinkage rate change due to temperature change is alleviated. As a result, the interlayer adhesion strength is improved and the difference in shrinkage rate due to temperature unevenness during heat shrinkage is reduced, resulting in improved finish.

[0094] (Mixing ratio of component (A) to component (C))

The content of the component (C) is 5 parts by mass or more, preferably 10 parts by mass or more, and 50 parts by mass or less, preferably 40 parts by mass or less with respect to 100 parts by mass of the component (A). It is preferable that If the component (C) is 5 parts by mass or less, the effect of addition cannot be obtained, and if it is 50 parts by mass or more, other shrinkage characteristics and rigidity tend to be affected.

[0095] (Other additives)

The layer (II) is used for the purpose of improving interlayer adhesion and reducing bulk specific gravity as long as various properties required as a surface layer, such as printability, solvent sealability, and adhesion resistance, are not impaired. In addition, a thermoplastic resin other than the polylactic acid-based resin composition can be included. This polylactic acid based resin Examples of the thermoplastic resin other than the composition include polyolefin resin, polystyrene resin, acrylic resin, amide resin, aliphatic polyester resin, aromatic polyester resin, and aliphatic aromatic resin. Examples include polyester-based rosin.

[0096] In addition, the resin composition in the layer (ii) is optionally provided with a plasticizer, a heat stabilizer, an antioxidant, a UV absorber, a light as long as the effects of the present invention are not impaired. Additives such as stabilizers, pigments, colorants, lubricants, nucleating agents and hydrolysis inhibitors may be added.

[0097] (Layer configuration of first pore-containing film)

The layer structure is not particularly limited as long as the first pore-containing film has at least two layers of the (I) layer and the (i) layer. Here, “having at least two layers of (1) layer and (Π) layer” means that the (Π) layer is laminated on one or both sides adjacent to (I) layer. In addition, the case of having a third layer for the purpose of improving adhesion, barrier property, concealment property, heat insulation property, etc. between the (I) layer and the (II) layer is also included.

[0098] A preferred layer structure is a two-layer / three-layer structure ((Π) layer Z (I) layer Ζ (Π) layer) having (I) layer as an intermediate layer and (Π) layer as a surface layer. Or the layer structure of 3 types and 5 layers with an adhesive layer between the intermediate layer and the surface layer ((II) layer Ζ adhesive layer Ζ (I) layer Ζ adhesive layer Ζ (Π) layer) It is.

[0099] The thickness ratio between the (I) layer and the (i) layer is not particularly limited as long as it is set in consideration of the above-described effects. For example, in the case of a film having a layer structure of (I) layer as an intermediate layer and (Π) layer as a surface layer, the thickness ratio of the (Π) layer to the total film thickness is 5% or more, preferably 10% or more, It is preferably 15% or more and 70% or less, preferably 50% or less, more preferably 45% or less, and most preferably 40% or less. The thickness ratio of the (I) layer to the total film thickness is 20% or more, preferably 25% or more, more preferably 30% or more, and 95% or less, preferably 90% or less, more preferably 85 % Or less. By adjusting the thickness ratio within the above range, it becomes easy to adjust the heat contraction rate appropriately.

[0100] When an adhesive layer is provided between the (I) layer and the (i) layer, the adhesive layer has a function of 0.5 μm or more, preferably 0.75 μm or more, more preferably It is 1 μm or more, 6 μm or less, preferably 5 μm or less. [0101] If the thickness ratio of each layer is within the above range, the first pore-containing film has excellent elasticity (rigidity at normal temperature), shrink finish, and natural shrinkage, and delamination of the film is suppressed. In addition, a heat-shrinkable laminated film suitable for applications such as shrink wrap, shrink-bound wrap and shrink labels can be obtained with good tolerance.

[0102] When the first pore-containing film has an adhesive layer between the (I) layer and the (Π) layer, the adhesive resin constituting the adhesive layer includes the (I) layer and the (II) layer. A part having reactivity or affinity for the component (A) contained as a main component of the component, and a part having affinity for the component (B) or the component (C) when the component (C) is used.榭脂 is preferably used.

[0103] Here, "having reactivity or affinity for component (A)" means having a functional group capable of reacting with (A) component or a functional group capable of reacting with component (A). Means that. Examples of functional groups having such properties include acid anhydride groups, carboxylic acid groups, carboxylic acid ester groups, carboxylic acid chloride groups, carboxylic acid amide groups, carboxylic acid groups, sulfonic acid groups, and sulfonic acid groups. Examples include ester groups, sulfonated chloride groups, sulfonate amide groups, sulfonate groups, epoxy groups, amino groups, imide groups, or oxazoline groups, among which acid anhydride groups, carboxylic acid groups, Or a carboxylic ester group is preferable.

[0104] Further, the "site having affinity with the component (B) or (C)" means having a chain having affinity with the component (B) or component (C), and more specifically Means having a straight-chain or branched saturated hydrocarbon moiety as a main chain, a block chain, or a graft chain. Specific examples include polyolefin resins or resins prepared by hydrogenating a copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon, such as a styrene ethylene butylene copolymer and a styrene ethylene propylene copolymer. .

[0105] As a specific product of the resin having a high affinity with the component (A) or a polar group capable of reacting and compatible with the component (B) or the component (C), For example, ethylene copolymer and ethylene methacrylic acid copolymer “bond first” with Sumitomo Chemical Co., Ltd. (Sumitomo Chemical Co., Ltd.) and modified styrene ethylene butadiene block copolymer “Tuftec” (Asahi Kasei Chemicals Corp.) ) And the like.

[0106] (Method for producing first pore-containing film)

The first pore-containing film is a mixed resin composition in which the component (A) and the component (B) are mixed. It is important that the (I) layer composed of (B) is stretched in at least one direction in a direction orthogonal to the major axis direction of the dispersion domain (B) component force. That is, the first pore-containing film is formed by laminating the (I) layer and the (i) layer composed of the (A) component as a main component and the (C) component as necessary. A method of stretching an unstretched film in at least one direction, or (I) a method of laminating an unstretched film or stretched film of layer (i) with heat or a solvent by a known method after stretching the layer in at least one direction Or (I) by stretching the layer in at least one direction and then coating (A) a resin composition having component strength by a known method (without using component (C)! /) Can be made

[0107] An example of a specific manufacturing method will be described.

First, as a method for mixing the component (A) and the component (B), there is a method for obtaining a pre-compound using a same-direction twin screw extruder, a kneader, a Henschel mixer, or the like. Alternatively, the two components may be directly fed into the film extruder without being mixed in advance, and mixing and film forming may be performed in the same apparatus.

[0108] In the first method for producing a pore-containing film, the component (A), the component (B), or a mixture obtained by compounding these components is put into an extruder and melt extrusion molded. As the extrusion method at this time, a known method such as a T-die method or a tubular method can be employed. The melt-extruded film is cooled with a cooling roll, air, water, or the like. Further, in the present invention, it is important that the (I) layer and the (積層) layer are laminated. As a force lamination method, a co-extrusion method using a multi-manifold type die, a feed block is used. Known methods such as a method of co-extrusion, a method of separately obtaining a single layer film of (I) layer and (i) layer, and laminating by thermal lamination can be employed.

[0109] The laminated unstretched film obtained is reheated by a method such as hot air, warm air, ultraviolet light, carbon dioxide laser, microwave, etc., and at least one direction is obtained by a roll method, a tenter method, a tubular method, etc. That is, the laminated film of the present invention can be produced by stretching in a uniaxial direction or biaxial direction, causing separation at the interface between the matrix and the domain, and forming pores. Whether the stretching is uniaxial stretching or biaxial stretching can be appropriately determined depending on the intended use.

[0110] The stretching temperature is determined based on the softening temperature of the component (A) and the component (B), and when used, the component (C). The force that can vary depending on the application of the heat-shrinkable pore-containing film obtained is preferably 60 ° C or higher, more preferably 65 ° C or higher, 85 ° C or lower, more preferably 80 ° C or lower. It is desirable to be. When the stretching temperature is 60 ° C. or higher, the elastic modulus of the raw material is prevented from becoming too high during the stretching process, and good stretchability can be obtained, and film breakage and thickness unevenness can be suppressed. On the other hand, if the stretching temperature is 85 ° C or lower, desired shrinkage characteristics can be exhibited, and the extensibility of the component (B) is suppressed, and peeling at the interface between the matrix and the dispersion domain is promoted. Sufficient pores can be obtained, and the bulk specific gravity can be less than 1.0.

[0111] The draw ratio in the drawing step is appropriately selected according to the composition of the mixed resin composition in which the components (A) and (B) are mixed, the drawing means, the drawing temperature, the target product form, and the like. can do. For example, the draw ratio is 1.5 times or more, preferably 3.0 times or more, and 8.0 times or less, preferably 6.0 times or less. If the draw ratio is 1.5 times or more, suitable shrinkage characteristics and sufficient pores can be obtained, and the bulk specific gravity can be adjusted to less than 1.0. In addition, a practical performance can be obtained by setting the upper limit of the draw ratio to about 8 times.

[0112] The stretching direction in the stretching step can be appropriately selected depending on the intended use, but the laminated film of the present invention has a structure in which the dispersion domain of the component (B) extends in the MD direction as described later. Therefore, it is preferable that pores can be easily formed by stretching in the direction perpendicular to the extension direction, that is, in the TD direction.

[0113] In addition, in the case of uniaxial stretching, heat-shrinkable pores can be obtained when weak stretching of about 1.0 to 1 to 1.8 times is applied in the direction perpendicular to the main shrinkage direction of the film as necessary. This is preferred because the mechanical properties of the film are improved.

[0114] In the present specification, the "main shrinkage direction" means a direction in which stretching is large between the longitudinal direction and the transverse direction, and is, for example, a direction corresponding to the outer circumferential direction when the bottle is mounted. . Further, the “direction orthogonal to the main shrinkage direction” refers to a direction orthogonal to the direction in which stretching is large.

[0115] (Method for adjusting the aspect ratio of the dispersion domain (B) component force in the (I) layer)

By the way, the cooling roll used in the film manufacturing process is located below the extruder. Due to the presence of the film, the film extruded by the extruder is slightly stretched by its own weight before reaching the cooling roll. At this time, the film is in a high temperature state because it is at the stage where the extruder is extruded. In the (I) layer constituting the film, not only the matrix (component (A)) but also the dispersion domain (component (B)) Is also extended in the direction perpendicular to the main shrinkage direction (flow direction), and in particular, the dispersion domain (component (B)) is stretched in the flow direction (direction perpendicular to the film main shrinkage direction). The aspect ratio of the dispersion domain (component (B)) at this time is 5 or more, preferably 10 or more, more preferably 15 or more, and is adjusted to 50 or less, preferably 40 or less, more preferably 35 or less. I hope that.

[0116] When a film composed of the component (A) alone is formed, the film itself becomes brittle. On the other hand, the heat-shrinkable pore-containing film obtained at low temperature can be obtained by including a dispersion domain having (B) component strength so that the aspect ratio is within the above range in the component (A) which is a matrix. Breaking resistance can be imparted. If the aspect ratio of the dispersion domain (component (B)) is 5 or more, the film can be given breakage resistance at low temperatures, and if the aspect ratio is 50 or less, the layer (I) It is easy to generate pores and a desired bulk specific gravity can be obtained.

[0117] The aspect ratio is preferably generated by a method based on the dead weight of the film. In such a case, it is desirable to stretch a little between the extruder and the cooling roll. That is, by changing the thickness of the stretched film to be formed with respect to the interval (lip gap) of the extrusion die of the extruder, the film is stretched in the flow direction (direction perpendicular to the main film shrinkage direction), and depending on the ratio It becomes possible to control the aspect ratio of the dispersion domain (component (B)).

[0118] When the dispersion domain (component (B)) has a predetermined aspect ratio, the dispersion domain (component (B)) is parallel to the outer surface of the film and is unidirectional, that is, The film stretches in the film flow direction (direction perpendicular to the main film shrinkage direction). For this reason, by making the stretching direction of uniaxial stretching or one stretching direction of biaxial stretching a direction perpendicular to the flow direction (film main shrinkage direction), the matrix (component (A)) and the dispersion domain ((B It is easier to cause separation of the boundary with the component), and a higher porosity can be obtained. [0119] (MFR of component (B))

In order to realize the aspect ratio of the dispersion domain (component (B)), the component (B) has a melt flow rate (MFR: JIS K7210, temperature: 190. C, load: value at 21.18N). It is desirable to use a polyolefin resin composition having a content of 1.0 gZlO or more, preferably 1.5 gZlO or more, 5. OgZlO or less, preferably 4.5 gZlO or less. If the melt flow rate of the polyolefin resin composition is 1. OgZio or more, the size of the dispersion domain becomes too large when the sea-island structure is formed, or the dispersion state is poor and the pores are uniform. It is suitable without causing problems such as << on the other hand

If the melt flow rate of the polyolefin resin composition is not more than 5. This is suitable without causing any troubles such as failure to sufficiently impart the fracture resistance.

[0120] (bulk specific gravity)

The bulk specific gravity of the first pore-containing film is 0.50 or more, more preferably 0.60 or more, further preferably 0.70 or more, less than 1.00, preferably 0.95 or less, more preferably It is desirable that it is 0.90 or less. If the bulk specific gravity is less than 1.00, it is easy and preferable to separate this film by the liquid specific gravity method. On the other hand, if the bulk specific gravity is 0.50 or more, it is preferable that there are no defects such as insufficient strength of the laminated film due to the existing pores.

[0121] As a method of adjusting the bulk specific gravity to a desired value, a method of increasing the mixing ratio of the component (A) and the component (B) having a smaller specific gravity, or increasing the draw ratio And a method of generating a large number of pores by operating stretching conditions such as lowering the stretching temperature.

[0122] The bulk specific gravity after heat shrinking in the range of 25% or less is preferably less than 1.00, preferably 0.95 or less, and more preferably 0.9 or less. If the bulk specific gravity is less than 1.00, it is preferable that the film is easily separated by the liquid specific gravity method even after heat shrinkage. In this case, the lower limit of the bulk specific gravity exceeds 0.50. Since the bulk specific gravity of the laminated film before heat shrinkage is 0.50 or more, the bulk specific gravity after heat shrinkage will not exceed 0.50. Ruka.

[0123] (Heat shrinkage)

The first pore-containing film has a thermal shrinkage rate of 20% or more, preferably 25% or more, more preferably 30% or more when immersed in 80 ° C warm water for 10 seconds. And it is desirable that it is 80% or less, preferably 75% or less. This is because, for example, in heat-shrinkable laminated films applied to PET bottle shrink label applications, the heat shrinkage rate is generally about 20% to 70%. This is in order to be able to respond appropriately in the usage.

[0124] Further, the shrinking machine that is most commonly used industrially for labeling of PET bottles is generally called a steam shrinker that uses steam as a heating medium for shrinking. is there. A heat-shrinkable film must be sufficiently heat-shrinkable at a temperature that is as low as possible in terms of point power, such as the effect of heat on the coated object. Furthermore, with the recent high-speed labeling process, there has been an increasing demand for shrinking quickly at a lower temperature. Considering such industrial productivity, a laminated film having a heat shrinkage rate of 20% or more under the above conditions is preferable because it can sufficiently adhere to the object to be coated within the shrinkage processing time. .

[0125] In the first pore-containing film, in order to adjust the heat shrinkage ratio in the main shrinkage direction when immersed in warm water of 80 ° C for 10 seconds to the above range, the composition of the resin is used in the present invention. While adjusting as described, it is preferable to adjust the stretching temperature to a range described later. For example, to increase the thermal shrinkage tl, increase the ratio of the optical isomers of the polylactic acid resin composition (A) in the (I) layer and the (層) layer. B) Lower the content of component, (i) When layer (C) contains component (C), lower the content of soft component (C) in layer (II), increase the draw ratio, lower the stretching temperature It is recommended to use means such as.

[0126] When the first pore-containing film is used as a heat-shrinkable label, the heat shrinkage rate in the direction perpendicular to the main shrinkage direction is 10 when immersed in warm water at 80 ° C for 10 seconds. % Is preferably 5% or less, and more preferably 3% or less. If the film has a thermal shrinkage rate of 10% or less in the direction perpendicular to the main shrinkage direction, the dimension itself in the direction perpendicular to the main shrinkage direction after shrinkage will be shortened, It is preferable that characters such as characters tend to be distorted, and that in the case of a square bottle, troubles such as vertical sink are unlikely to occur.

[0127] (Natural contraction rate)

The natural shrinkage rate of the first pore-containing film is preferably as small as possible, but in general, the natural shrinkage rate of the heat-shrinkable laminated film is, for example, 3 after 30 days storage at 30 ° C. Desirably, it is 0% or less, preferably 2.0% or less, and more preferably 1.5% or less. If the natural shrinkage rate under the above conditions is 3.0%, even if the produced film is stored for a long period of time, it can be stably attached to a container or the like, and practical problems are unlikely to occur.

[0128] In the first pore-containing film, in order to adjust the natural shrinkage ratio to the above range, the resin composition is adjusted as described in the present invention, and the stretching temperature is adjusted to the range described later. Is preferred. For example, to further reduce the natural shrinkage, reduce the optical isomer ratio of the polylactic acid-based rosin composition (A), reduce the content of component (B), (II) layer ( When the component (C) is included, the content of the soft component (C) is decreased, the stretching ratio is decreased, the stretching temperature is increased, the temperature for heat setting after stretching is increased, the time for heat setting after stretching is increased, etc. It is good to use the means.

[0129] (Fracture resistance)

The fracture resistance of the first pore-containing film was evaluated by the bow I tension elongation, and in the tensile test under the environment of 0 ° C, especially in the label application, the elongation rate in the film take-off (flow) direction (MD) Is 100% or more, preferably 150% or more, more preferably 200% or more. A tensile elongation at break of 100% or more under an environment of 0 ° C is preferable because it is difficult to cause problems such as film breakage during a process such as printing and bag making. In addition, when the tension applied to the film increases as the speed of processes such as printing and bag making increases, it is preferable that the tensile elongation at break is 100% or more because it is difficult to break.

[0130] The upper limit is not particularly limited, but considering the current process speed, it is considered that about 500% is sufficient, and when trying to give too much elongation, the stiffness (tensile modulus) of the film is low. It tends to decrease.

[0131] In the first pore-containing film, the tensile elongation at break at 0 ° C is adjusted to the above range. In order to adjust, it is preferable to adjust the resin composition as described in the present invention and to adjust the stretching temperature to a range described later. For example, if you want to improve the tensile elongation at break, increase the content of component (B). If the component (C) is included in the layer (II), increase the content of soft component (C). Use a means such as raising or giving weak extension to MD.

[0132] (Rigidity (tensile modulus))

The waist (stiffness at room temperature) of the first pore-containing film is preferably 1.20 GPa or higher in the tensile modulus in the direction perpendicular to the main shrinkage direction of the first pore-containing film. More preferred is 40 GPa 1. More preferred is 60 GPa or more. Further, the upper limit of the tensile elastic modulus of the heat-shrinkable film that is usually used is about 3. OOGPa, preferably about 2.90 GPa, and more preferably about 2.80 GPa. If the tensile modulus of elasticity in the direction perpendicular to the main shrinkage direction of the first pore-containing film is 1.2 GPa or more, the overall film stiffness (rigidity at room temperature) can be increased. Even when the pore-containing film is thinned, the yield decreases due to slanting or laminating the laminated film when the film made in a plastic bottle or other container is covered with a labeling machine. This is preferable because it causes problems such as wiping and sifting 1.

[0133] Further, since the first pore-containing film has pores, the light rays are refracted and reflected at the interface between the component (A) or the component (B) and the air, and the appearance of an opaque white color as a whole For example, it is particularly suitable for applications where light shielding properties are required. Furthermore, since it has pores, its heat conduction efficiency is lower than that of ordinary thermoplastic resin, and it is particularly suitable for applications that require heat insulation and heat retention, such as labels for hot beverages. In addition, since it has pores, it has excellent cushioning properties and is suitable for protective applications such as frangible flaws and flaws!

[0134] The upper limit is not particularly limited, but it is generally about 3. OOGPa. 3. If it is less than OOGPa, the elastic modulus will be too high and it will be difficult to cause problems such as a stiff texture during use.

[0135] In the first pore-containing film, in order to adjust the waist at room temperature to the above range, the resin composition is adjusted as described in the present invention, and the stretching temperature is adjusted to the range described later. It is preferable. For example, if you want to improve your waist more, lower the content of component (B), lower the content of soft component (C), or stretch slightly in the direction perpendicular to the main shrinkage direction. Use a means such as

[0136] (Use)

Since the first pore-containing film has pores, the light rays are refracted and reflected at the interface between the (A) component resin or the (B) component resin and the air, and as a whole, it has an opaque white-like appearance. Therefore, it is particularly suitable for applications that require light shielding properties, for example. Furthermore, since it has pores, its heat conduction efficiency is lower than that of ordinary thermoplastic resin, and it is particularly suitable for applications that require heat insulation and heat retention such as labels for hot beverages. In addition, since it has pores, it has excellent cushioning properties and is suitable for protective applications such as fragile!

[0137] (Molded products, heat-shrinkable labels and containers)

The first pore-containing film is excellent in printability, high rigidity, rupture resistance, shrink finish, etc. of the film, and its use is not particularly limited. By forming a vapor deposition layer and other functional layers, it can be used as various molded products such as bottles (blow bottles), trays, lunch boxes, prepared food containers, and dairy products containers. In particular, when the laminated film of the present invention is used as a heat-shrinkable label for food containers (for example, PET bottles, glass bottles, preferably PET bottles for soft drinks or foods), a complicated shape (for example, a cylinder with a narrow center) A rectangular column, pentagonal column, hexagonal column, etc.) can be adhered to the shape, and a container with a beautiful label without any shivabata is obtained. The molded article and container of this invention can be produced by using a normal molding method.

[0138] When the first pore-containing film is used as a heat shrink label for PET bottles or the like, it is in a contracted state at the time of recycling, but it is preferable that it can be separated by a liquid specific gravity method even after the contraction. . Specifically, for example, the bulk specific gravity after shrinking in the range of 25% or less is 0.50 or more and less than 1.00, preferably 0.60 or more and 0.95 or less, more preferably 0.70 or more and 0.000 or more. 90 or less is desirable. If the bulk specific gravity after shrinkage is less than 1.00, the film can be separated by the liquid specific gravity method and can be separated. On the other hand, if the bulk specific gravity after shrinkage is 0.50 or more, it is preferable that there are no defects such as insufficient strength of the film due to the existing pores. [0139] The first pore-containing film has excellent low-temperature shrinkage and shrinkage finish properties, and therefore, in addition to the heat-shrinkable label material of plastic molded products that deform when heated to high temperatures, A material whose water absorption is very different from the heat-shrinkable film of the present invention, for example, polyolefin resin such as metal, porcelain, glass, paper, polyethylene, polypropylene, polybutene, polymethacrylate ester resin, polycarbonate resin In addition, it can be suitably used as a heat-shrinkable label material for a package (container) using at least one selected from polyester-based resin such as polyethylene terephthalate and polybutylene terephthalate, and polyamide-based resin as a constituent material.

[0140] Examples of the material constituting the plastic package in which the first pore-containing film can be used include polystyrene, rubber-modified impact-resistant polystyrene (HIPS), and styrene-butyl acrylate copolymer in addition to the above-mentioned resin. , Styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), methacrylic acid ester butadiene styrene copolymer (MBS), polychlorinated bur resin, Examples include enol resin, urea resin, melamine resin, epoxy resin, unsaturated polyester resin, and silicone resin. These plastic packages may be a mixture of two or more types of resin or a laminate.

[0141] <Second pore-containing film>

The second pore-containing film comprises an unstretched film comprising the above-mentioned component (A), component (B) and component (C) in a predetermined ratio, or having at least one mixed resin composition layer. It is a film stretched at least in the uniaxial direction.

[0142] The DZL ratio of the component (A) in the second pore-containing film is preferably in the range of L lactic acid ZD lactic acid = 99 Zl to 85 Zl5, or 1Z99 to 15 Z85. / 12, or 3/97 to 12/88 is more preferable than force S, 97/3 to 90 Z10, or 3Z97 to: LOZ90 is more preferable 97/3 It is more preferably in the range of ~ 93 Z7, or in the range of 3Z97 to 7Z93. If the DZL ratio is within the above range, in the pore forming process described later, sufficient pore formation can be caused, and a film having the desired bulk specific gravity can be obtained, and shrinkage unevenness can be suppressed, Easily obtain a film with sufficient shrinkage characteristics. [0143] The component (A) and the component (B) in the second pore-containing film are the characteristics of the (I) layer of the first pore-containing film (mixing ratio and other columns of additives). This is consistent with the characteristics described in (1).

[0144] (mixing ratio of component (C))

The mass ratio of the component (A) to the component (C) in the second pore-containing film must be 10 parts by mass or more for the component (C) with respect to 100 parts by mass of the component (A). Yes, it is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more. In addition, the upper limit of the component (C) is 80 parts by mass or less, and more preferably 70 parts by mass or less. If the content of the component (C) is 10 parts by mass or more with respect to 100 parts by mass of the polylactic acid-based resin composition, it is preferable because fracture resistance can be imparted. On the other hand, if the content is 80 parts by mass or less, the rigidity is not lowered.

[0145] (Component (D))

When the second pore-containing film contains the component (B) that is incompatible with the component (A), the second pore-containing film can contain pores, thereby suppressing light transmittance (that is, providing light shielding properties). However, the light transmittance can be further suppressed by incorporating the component (D) inside.

[0146] The content of the component (D) contained in the second pore-containing film is determined by taking into consideration the light shielding properties, mechanical properties, productivity, etc. of the second pore-containing film. B) 100 parts by weight in a mixed fat with component, 1 part by weight or more, preferably 2 parts by weight or more, more preferably 5 parts by weight or more, 25 parts by weight or less, preferably 20 parts by weight or less, More preferably, it should be 15 parts by mass or less.

[0147] When the second pore-containing film has pores, the component (D) plays an auxiliary role in the light-shielding function. Therefore, if the content is 1 part by mass or more, the component is sufficiently shielded from light. It can function as a film. In addition, when the content of component (D) is 25 parts by mass or less, the functions, fracture resistance, and shrinkage characteristics necessary for a heat shrink film can be secured.

[0148] (Additional additives)

The second pore-containing film is used as a surface layer such as printability, solvent sealability, and fusing resistance. Other than the (A) component, the (B) component, the (C) component, and the (D) component used as necessary for the purpose of reducing the bulk specific gravity and the like within a range that does not impair the required properties. Can be included. Examples of such a resin include acrylic resin, amide resin, aliphatic polyester resin, aliphatic aromatic polyester resin, and the like.

[0149] (Hole)

In the resin composition containing the component (A), the component (B), the component (C), and the component (D) as necessary, the component (A) and the component (C) form a matrix. , (B) component, and (D) component used as necessary form a dispersion domain. By stretching the single layer film comprising the above-mentioned rosin composition containing the component (B) (and the component (D) used as needed) at the above-mentioned mass ratio and forming a sea-island structure as a whole, a matrix is obtained. It is possible to form vacancies by causing separation at the interface between the particles and the dispersion domain. As a result, a film having a small bulk specific gravity, which will be described later, and a good light shielding property and heat insulating property can be obtained. The size and shape of the dispersion domain can be appropriately determined depending on kneading conditions, sheeting conditions, stretching ratio, stretching direction, and the like. The longitudinal direction of the dispersed domain after stretching, that is, the cross-sectional shape in the direction parallel to the stretching direction is preferably elliptical. When the cross-sectional shape is an ellipse, the maximum axial length in the minor axis direction of this dispersion domain is preferably 0.1 m or more, more preferably 0.3 or more, and further 0.3 m or more. preferable. On the other hand, the maximum axial length in the minor axis direction is preferably 5 m or less, more preferably 4 m or less. If the maximum axial length in the minor axis direction is 0.1 m or more, peeling occurs at the interface between the matrix and the dispersion domain, which is suitable for forming pores, and this maximum axial length is 5 m or less. If so, it is preferable that remarkable unevenness is hardly generated on the surface and the appearance can be kept uniform.

[0150] (Aspect ratio)

During the production of the second pore-containing film, the dispersion component (particularly the component (B)) as well as the matrix component (that is, the component (A) and the component (C)) is also perpendicular to the main shrinkage direction (flow direction). In particular, the dispersion domain (particularly component (B)) is stretched in the flow direction (direction perpendicular to the main film shrinkage direction). The aspect ratio of the dispersion domain (particularly component (B)) at this time is greater than 1, preferably 3 or more, more preferably 5 or more, and 50 In the following, it is desirable to adjust to 40 or less, more preferably 35 or less. If the aspect ratio of the dispersion domain (particularly component (B)) is larger than 1, it is easy to generate pores when stretched in the direction perpendicular to the flow direction, and if the aspect ratio is 50 or less, the dispersion domain is It is preferable that it is difficult to cause a defect that pores are not easily generated even if stretched due to excessive tension.

[0151] When the dispersion domain (particularly component (B)) has a predetermined aspect ratio, the dispersion domain is parallel to the outer surface of the monolayer film and is unidirectional, that is, a monolayer film. Stretched in the flow direction (direction perpendicular to the main shrinkage direction of the single layer film). For this reason, the matrix ((A) component and (C) component) can be obtained by setting one stretching direction of uniaxial stretching or one stretching direction of biaxial stretching to a direction perpendicular to the flow direction (single layer main shrinkage direction). And the dispersion domain (particularly the component (B)) are more likely to be separated, and more vacancies can be formed.

[0152] In this specification, the "main shrinkage direction" means a direction having a large shrinkage rate in the longitudinal direction and the transverse direction, and, for example, a direction corresponding to the outer circumferential direction when the bottle is attached to the bottle. It is. Further, the “direction perpendicular to the main shrinkage direction” refers to a direction perpendicular to the direction in which yield shrinkage is large.

[0153] (Method for producing second pore-containing film)

The second pore-containing film can be produced by stretching at least a uniaxial direction of an unstretched film made of the above-described resin composition or having at least one layer of the mixed resin composition layer. Specifically, first, the (A) component, the (B) component, and the (C) component are mixed at the mass mixing ratio described above to obtain the greave composition. In addition, additives such as plasticizers, heat stabilizers, antioxidants, UV absorbers, light stabilizers, pigments, colorants, lubricants, nucleating agents, and hydrolysis inhibitors should be added as necessary. I can do it. As a method of mixing, for example, there is a method of obtaining a pre-compound using a unidirectional twin-screw extruder, a kneader, a Henschel mixer or the like.

[0154] Next, as a method for forming the second pore-containing film, the resin composition is charged into an extruder and melt-extruded. The film can be either flat or tube-shaped, but it can be productive (a few products can be taken in the width direction of the original film) A planar shape is preferable in that printing is possible on the surface. The melt-extruded film is cooled with a cooling tool, air, water or the like. As the extrusion method at this time, a known method such as a T-die method or a tubular method can be employed.

[0155] Next, roll-stretching is performed in the vertical direction, tenter-stretching is performed in the horizontal direction, annealing, cooling, and when printing is performed, corona discharge treatment is performed on the surface, and the sheet is removed by a scraper. The film can be obtained by winding up.

[0156] Another example is a method of cutting a film produced by a tubular method into a flat shape.

[0157] The polylactic acid-based resin composition (A) and the polyolefin-based resin composition (B), which are constituents of the resin mixture, in which the film is not formed after these components are mixed in advance. ) And the soft component (C) may be directly introduced into a film extruder, and mixing and film forming may be performed in the same apparatus.

[0158] The obtained unstretched monolayer film is reheated by a method such as hot air, warm air, ultraviolet light, carbon dioxide laser, or microwave, and is at least in one direction by a roll method, a tenter method, a tubular method, or the like. That is, by stretching in a uniaxial direction or biaxial direction, peeling occurs at the interface between the matrix and the domain, and pores are formed, whereby the heat-shrinkable pore-containing film according to the present invention can be produced. Whether the stretching is uniaxial stretching or biaxial stretching can be appropriately determined depending on the use of the monolayer film to be produced.

[0159] The temperature at which the stretching is performed includes the softening temperature of the component (A), the component (B), the component (C), and the component (D) used as necessary, and the second voids obtained. The force that can vary depending on the use of the contained film, etc. 60 ° C. or more is preferred. 65 ° C. or more is more preferred, and 70 ° C. or more is more preferred. When the stretching temperature is 60 ° C. or higher, the raw material has a high modulus of elasticity during the stretching process, and it is difficult to obtain good stretchability, and it is difficult to cause defects such as film breakage and thickness unevenness. On the other hand, 100 ° C or less is preferable 90 ° C or less is preferable 85 ° C or less, and more preferable 80 ° C or less is more preferable. If the stretching temperature is 100 ° C or less, the desired shrinkage characteristics cannot be exhibited, and peeling at the interface between the matrix and the dispersion domain is not promoted, so that it is difficult to produce defects such as insufficient pores. Is preferred. [0160] The draw ratio at the time of drawing is the composition of the resin composition in which the component (A), the component (B), the component (C), and the component (D) used as necessary are mixed. It can be selected as appropriate according to the composition, stretching means, stretching temperature, desired product form, etc., but in the case of biaxial stretching, it is preferred that it is 1.5 times or more in both the longitudinal and transverse directions. 2 times or more is more preferable 3 times or more is more preferable. If the draw ratio is 1.5 times or more, it is preferable that sufficient pores cannot be obtained and a desired function cannot be obtained, and the draw ratio is preferably 10 times or less. 8 times or less is preferable and 6 times or less is more preferable. If it is 10 times or less, it is possible to obtain practical performance without causing problems such as a problem in strength, and it is possible to sufficiently form holes.

[0161] Also, in applications that shrink mainly in one direction, such as for heat-shrinkable labels, the lateral direction is preferably 1.5 times or more, more preferably 2 times or more, and more preferably 3 times or more. preferable. If the draw ratio is 1.5 times or more, it is preferable that sufficient pores cannot be obtained and the desired function cannot be obtained, and it is preferable. On the other hand, the draw ratio is 8 times or less. If it is less than 7 times, it is preferable. If it is less than 6 times, it is more preferable if it is less than 5 times. If it is 8 times or less, it is possible to obtain practical performance without causing problems such as a problem in strength, and it is possible to sufficiently form holes. Furthermore, a biaxially stretched film stretched at a stretch ratio in the above range does not have a too high heat shrinkage rate in the direction orthogonal to the main shrinkage direction.For example, when used as a shrinkage label, V is preferable because the film shrinks in the height direction of the container.

[0162] The stretching direction in the stretching step at this time can be appropriately selected depending on the intended use. However, the film of the present invention has the polyolefin resin composition (B) in the film take-off direction (MD). Therefore, it is preferable to extend in the direction perpendicular to the extension direction (TD) because pores can be easily formed.

[0163] Even in the case of uniaxial stretching, it can be obtained by applying a weak stretching of 1.01 to 1.5 times, preferably about 1.8 times in the direction perpendicular to the main shrinkage direction of the film, if necessary. It is more preferable because the mechanical properties of the heat-shrinkable pore-containing film obtained are improved.

[0164] The stretched second pore-containing film can reduce the natural shrinkage rate or heat shrink as necessary. After heat treatment or relaxation treatment at a temperature of about 50 ° C or more and 100 ° C or less for the purpose of improving the characteristics, etc., the film is quickly cooled within a time period in which the molecular orientation does not relax and becomes a heat-shrinkable film.

[0165] In addition, the second pore-containing film may be subjected to surface treatment and surface treatment such as corona treatment, printing, coating, and vapor deposition, as well as bag-making processing and perforation using various solvents and heat sealing. Processing can be performed.

[0166] The stretching direction in this stretching step can be appropriately selected depending on the intended use, but the second pore-containing film has a structure in which the dispersion domain of the (B) component extends in the MD direction as described later. Therefore, it is preferable that pores can be easily formed by stretching in the direction perpendicular to the extension direction, that is, in the TD direction.

[0167] In addition, in the case of uniaxial stretching, heat-shrinkable pores can be obtained when weak stretching of about 1.0 to 1 to 1.8 times is applied in the direction perpendicular to the main shrinkage direction of the film as necessary. This is preferred because the mechanical properties of the film are improved.

[0168] By the way, since the cooling roll used in the second pore-containing film manufacturing method exists below the extruder, the film extruded by the extruder reaches the cooling roll. By the time, due to its own weight, it is in a slightly stretched state. At this time, the film is in a high temperature state because it is at the stage where the extruder force is extruded, and when the second pore-containing film contains the component (B), (A) only the matrix having the component force can be used ( The dispersion domain consisting of component B) is also extended in the direction (flow direction) perpendicular to the main contraction direction. For this reason, in particular, the dispersion domain (B) component force is in a state of being stretched in the flow direction (direction perpendicular to the main film shrinkage direction). At this time, the fracture resistance of the film can be improved by adjusting the aspect ratio of the dispersion domain which also has the component force (B).

[0169] That is, the aspect ratio of the dispersion domain is preferably generated by a method of self-weighting the film, but this may not be sufficient. In such a case, it is desirable to stretch a little between the extruder and the cooling roll. That is, by changing the thickness of the stretched film to be formed with respect to the interval (lip gap) of the extrusion die of the extruder, the film is stretched in the flow direction (direction perpendicular to the main film shrinkage direction), and the ratio Thus, the aspect ratio of the dispersion domain (component (B)) can be controlled. [0170] (When adopting laminated structure)

The second pore-containing film may be used as a single layer, shrinkage adjustment, printability, solvent sealability, barrier properties, concealment properties, heat insulation properties, readability, slip properties, heat resistance, solvent resistance For the purpose of improving easy adhesion, etc., the layers may be laminated so as to have two or more layers. Examples of the layer to be laminated include a printing layer and a vapor deposition layer. When used in a single layer configuration, the thickness of the second pore-containing film is 30 μm or more, preferably 40 μm or more, more preferably 50 μm or more, and powerfully 200 μm or less, preferably Is preferably 175 μm or less, more preferably 150 m or less. Further, when used in a laminated structure, it is preferably used as an intermediate layer. In that case, the thickness ratio of the film of the present invention to the thickness of the entire film is 20% or more, preferably 25% or more, more preferably 30% or more, and 95% or less, preferably 90% or less, more preferably It should be 85% or less.

[0171] When the second pore-containing film is used as a part of the laminated structure, the layer structure is not particularly limited. If the second layer comprising the second pore-containing film is the first layer, the printed layer, the vapor-deposited layer, etc., is denoted as the second layer, the layer structure is adjacent to the first layer and the second layer is on one side or Not only is it laminated on both sides, but it has a third layer for the purpose of improving adhesion, barrier properties, hiding properties, heat insulation, etc. between the first and second layers. Cases are also included. Preferably, the first layer as the intermediate layer and the second layer as the surface layer and the three layers of the two layers (second layer Z first layer Z second layer), or an adhesive layer between the intermediate layer and the surface layer And a layer configuration such as a three-layer five-layer configuration (second layer Z adhesive layer Z first layer Z adhesive layer Z second layer). Furthermore, as an example of using the third layer, the second layer Z, the first layer Z, the third layer, the second layer Z, the first layer Z, the third layer Z, the second layer, and the like can be given.

[0172] There are no particular limitations on the resin yarn and composition used in layers other than the first layer, but considering the adhesiveness to the first layer and the recyclability of the entire film, the first layer It is preferable that the polylactic acid based resin composition (A) used is used as a main component. Furthermore, the second layer has improved interlayer adhesion, reduced bulk specific gravity, and fracture resistance within the range that does not impair various properties required for the surface layer, such as printability, solvent sealability, and fusing resistance. For the purpose of improving the viscosity and adjusting the shrinkage properties, a thermoplastic resin other than the polylactic acid-based resin composition can be included. Po Examples of thermoplastic resins other than the lactic acid-based resin composition include polyolefin resin, polystyrene resin, acrylic resin, amide resin, aliphatic and Z or aromatic polyester resin Among them, the polyolefin resin composition (B) and the soft component (C) described above can be preferably used.

[0173] In the laminated structure using the second pore-containing film, a preferred layer structure is a case where the second layer is a layer mainly composed of a polylactic acid-based resin. In particular, the DZL ratio of the polylactic acid-based resin constituting the second layer is preferably different from the DZL ratio constituting the first layer. By adjusting the DZL ratio and changing the crystallinity to be different in the first layer and the second layer, it is possible to achieve better shrinkage finish.

[0174] When the second pore-containing film contains pores, in addition to this layer, a second layer having no pores or having a low pore content should be disposed. As a result, printability, solvent sealability, etc. can be improved. Further, by changing the DZL ratio of the polylactic acid-based resin used in the first layer and the second layer, the void formation / shrinkage characteristics can be adjusted within a preferable range.

[0175] Examples of a method for forming this laminate include a co-extrusion method, a method of forming a film of each layer and then heat-sealing them with each other, a method of bonding with an adhesive, and the like.

[0176] The total thickness of the second pore-containing film is not particularly limited, whether it is a single layer or a laminated structure, but is thin from the viewpoints of transparency, shrinkage workability, raw material cost, etc. Is preferred. Specifically, the total thickness of the stretched film is preferably 150 m or less, more preferably 100 / z m or less, and even more preferably 80 m or less. Further, the lower limit of the total thickness of the film is not particularly limited, but is preferably 20 μηι or more in consideration of the handleability of the film.

[0177] In addition, if necessary, the cocoon yarn and the composition constituting the first layer and the second layer may include a plasticizer, a heat stabilizer, an antioxidant, and the like within a range not impairing the effects of the present invention. Additives such as UV absorbers, light stabilizers, pigments, colorants, lubricants, nucleating agents, and hydrolysis inhibitors may be added.

[0178] The above-mentioned laminated film is a method in which an unstretched film in which a first layer and other layers are laminated is stretched in at least one direction, or after the first layer is stretched in at least one direction, the other layers are unstretched. A method of laminating a film or a stretched film with heat or a solvent by a known method, or the other layer after stretching the first layer in at least one direction Can be prepared by a known method for coating a rosin composition used in

[0179] (Heat shrinkage)

The second pore-containing film needs to have a shrinkage rate of 20% or more when immersed in warm water at 80 ° C for 10 seconds, preferably 25% or more, more preferably 30% or more, and even more preferably. Or 40% or more, more preferably 45% or more, and still more preferably 50% or more. On the other hand, the shrinkage ratio needs to be 80% or less, preferably 75% or less, and more preferably 70% or less. This requires a heat shrinkage rate of at least 20% to be used as a heat shrinkable label, such as a heat shrinkable label used in packaging of PET bottles, etc., while heat shrinkage exceeds 80%. This is because it becomes difficult to control the later form. The shrinkage rate is the difference in length before and after shrinkage when the original length is 100%.

[0180] At present, an example of a shrinkage caloe machine that is most widely used industrially for labeling of PET bottles is generally referred to as a steam shrinker that uses steam as a heating medium for shrinkage processing. There is. A heat-shrinkable label must be sufficiently heat-shrinkable at the lowest possible temperature in view of the influence of heat on the object to be coated, and moreover, it shrinks quickly at a lower temperature due to the recent high-speed labeling process. The demand to do has increased. In consideration of such industrial productivity, a single-layer film having a heat shrinkage rate of 20% or more under the above conditions is preferable because it can sufficiently adhere to the object to be coated within the shrinkage processing time.

[0181] In the second pore-containing film, in order to adjust the heat shrinkage ratio in the main shrinkage direction when immersed in warm water of 80 ° C for 10 seconds to the above range, the composition of the resin is used in the present invention. While adjusting as described, it is preferable to adjust the stretching temperature to a range described later. For example, if the heat shrinkage rate is further increased, in the case of increasing the optical isomer ratio of the polylactic acid-based resin composition (A), increasing the content of the soft component (C), and increasing the draw ratio. Means such as increasing the stretching temperature or lowering the stretching temperature may be used.

[0182] When the second pore-containing film is used as a label, the thermal shrinkage rate in the direction perpendicular to the shrinkage direction of the film is 10% or less when immersed in warm water at 80 ° C for 10 seconds. is there More preferably, it is 5% or less, more preferably 3% or less. If the film has a thermal shrinkage rate in excess of 10% in the direction perpendicular to the main shrinkage direction, the dimensions in the direction perpendicular to the main shrinkage direction after shrinkage may be shortened, and the printed pattern or characters may be distorted after shrinkage. Problems such as easy sinking and troubles such as vertical sinks cannot be ignored in the case of square bottles.

[0183] (Natural contraction rate)

The natural shrinkage rate of the second pore-containing film is desirably as small as possible.For example, the natural shrinkage rate after storage at 30 ° C for 30 days is 3.0% or less, preferably 2.0% or less. Preferably it is 1.5% or less. If the natural shrinkage rate under the above conditions is 3.0% or less, even if the produced film is stored for a long period of time, it can be stably attached to a container etc. If it exceeds 0%, there may be a problem in adhesion stability.

[0184] In the second pore-containing film, in order to adjust the natural shrinkage ratio to the above range, the resin composition is adjusted as described in the present invention, and the stretching temperature is adjusted to the above range. Is preferred. For example, when it is desired to further reduce the natural shrinkage, the optical isomer ratio of the polylactic acid-based rosin composition (A) is reduced, the content of the soft component (C) is reduced, and the draw ratio is increased. It is preferable to use means such as reducing the temperature, increasing the stretching temperature, increasing the temperature of heat setting after stretching, or extending the heat setting time after stretching.

[0185] (bulk specific gravity)

In addition, since the second pore-containing film has pores, the bulk specific gravity when the second pore-containing film is used is lower than the true specific gravity of the resin used for the film of the present invention. The ratio of the bulk specific gravity to the true specific gravity of the film of the present invention is 50% or more, preferably 60% or more, more preferably 70% or more, and 95% or less, preferably 90% or less, more preferably 85. % Or less is desirable. When the ratio of the bulk specific gravity to the true specific gravity is less than 50%, there is a possibility that defects such as insufficient strength of the film may occur due to the excessive proportion of the pores. On the other hand, if it exceeds 90%, the formation of pores is so small that the light shielding property and the heat insulating property may be insufficient.

[0186] If the bulk specific gravity is less than 1.0, the second pore-containing film is made of polyethylene terephthalate. When the one used as a coated label for a rate bottle is disposed of, it can be easily separated from polyethylene terephthalate by a liquid specific gravity method, which is more preferable.

[0187] Examples of a method for adjusting the bulk specific gravity to a desired value include a method of increasing the mixing ratio of components having a small specific gravity among the components (A), (B) and (C), and stretching. Examples include a method in which a large number of pores are generated by manipulating stretching conditions such as increasing the magnification within the above range and lowering the stretching temperature.

[0188] (Light transmittance)

The second pore-containing film is an opaque white light-blocking film in which light rays are refracted and reflected at the interface between the resin composition and the pores, and part of the light rays are absorbed in the resin composition. (Light-shielding property). 240nm or more and 800nm or less (ultraviolet-visible region), including the ultraviolet region of 240nm or more and 400nm or less, which may deteriorate or alter the contents, and the visible region of 400nm or more and 8OOnm or less related to the concealment of the contents However, the light transmittance measured based on JIS K 7015 is required to be 50% or less at any wavelength, and is preferably 40% or less and more preferably 30% or less. It is more preferable that it is 25% or less, and it is still more preferable that it is 20%. If it is 50% or less, the light-shielding property is sufficient, and it is preferable that the problem of lack of content protection and concealment is difficult to be exhibited.

[0189] Furthermore, for the purpose of content protection in particular, the average wavelength range is preferably 20% or less in the ultraviolet region of 240 nm or more and 400 nm or less, which degrades or alters the content, and 10% or less. It is even more preferable that it is 5% or less.

[0190] In the second pore-containing film, in order to adjust the light transmittance of 240 nm or more and 800 nm or less to the above range, the resin composition is adjusted as described in the present invention, and the stretching temperature is adjusted. It is preferable to adjust to the above-mentioned range. For example, to further reduce the light transmittance, reduce the ratio of the optical isomers of component (A), increase the content of components (B) and (D), and contain component (C). It is advisable to use means such as reducing the amount, increasing the draw ratio, and lowering the stretching temperature. It is also effective to add pigments, colorants, inorganic particles, etc. within a range that does not deteriorate various properties such as shrinkage and rupture resistance. In particular, to adjust the light transmittance in the ultraviolet region from 240 nm to 400 nm in the above range, (D) Preference is given to using acid titanium as a fraction.

[0191] (Heat conduction efficiency)

Furthermore, since the second pore-containing film has pores, the heat conduction efficiency is lower than that of a film using a general thermoplastic resin without pores. For this reason, it can be particularly suitably used for applications requiring heat insulation and heat retention properties such as labels for hot beverages.

[0192] Beverages that are heated and sold by hot-warmers such as beverage vending machines and convenience stores are sold at 60-70 ° C, considering the temperature distribution in the vending machine. . This beverage container made of metal has a significantly higher thermal conductivity than glass or rosin beverage containers, so even if it is heated at the same temperature, it feels more hot and immediately. It is necessary to relieve the heat. The heat-shrinkable film of the present invention has pores, and by covering this, it becomes difficult for heat to be transmitted to the beverage container force, so that it can be suitably used.

[0193] Examples of methods for further increasing the heat insulating property and heat retention include decreasing the optical isomer ratio of the component (A), increasing the content of the component (B), and decreasing the content of the component (C). It is advisable to use means such as increasing the stretching ratio or lowering the stretching temperature.

[0194] (Fracture resistance)

The fracture resistance of the second pore-containing film is evaluated by the tensile elongation at break according to JIS K7127. In tensile tests at 0 ° C, especially for label applications, the tensile elongation at break in the film take-off direction (MD) is preferably 100% or more, more preferably 150% or more, and more preferably 200% or more. More preferably. If the tensile elongation at break in an environment of 0 ° C is less than 100%, there is a high possibility that the film breaks during the process of printing and bag making. Further, if the tensile elongation at break is 150% or more, it is more preferable that the film is hard to break even when the tension applied to the film increases as the speed of processes such as printing and bag making increases. Although no upper limit is specified, considering the current process speed, it can be considered that about 500% is sufficient.

[0195] In the second pore-containing film, in order to adjust the tensile elongation at break in the environment of 0 ° C to the above range, the resin composition is adjusted as described in the present invention and stretched. It is preferable to adjust the temperature to a range described later. For example, the tensile elongation at break was further improved In such a case, it is advisable to use means such as increasing the content of the soft component (C) or giving weak extension to MD.

[0196] (Rigidity)

The stiffness of the second pore-containing film, that is, the rigidity at room temperature, is preferably 1.20 GPa or higher in the tensile modulus in the direction orthogonal to the main shrinkage direction. 1. More preferably 40 GPa or higher. 1. More preferably, it is 60 GPa or more. 1. If it is less than 20 GPa, especially when the thickness of the single-layer film is reduced, when the film made in a plastic bottle or other container is covered with a labeling machine, it may be slanted or the single-layer film may be folded back. This can lead to problems such as a decrease in yield and a problem of screening. On the other hand, the upper limit of the tensile modulus of heat-shrinkable film is generally about 3. OOGPa, preferably about 2.90 GPa, and more preferably about 2.80 GPa. 3. If it is OOGPa or less, the elastic modulus is too high, and it is preferable that it does not easily cause a malfunction such as a stiff texture during use.

[0197] In the second pore-containing film, in order to adjust the waist at room temperature to the above range, the resin composition is adjusted as described in the present invention, and the stretching temperature is adjusted to the range described later. It is preferable. For example, when it is desired to further improve the waist, it is preferable to use means such as lowering the content of the soft component (C) or giving weak stretching in a direction orthogonal to the main shrinkage direction.

[0198] (Use)

When the second pore-containing film contains the component (B), the second pore-containing film has pores, so that light rays are refracted and reflected at the interface between the component (A) or the component (B) and air, and (D When the component) is added, it will appear as an opaque white-like appearance as a whole, and is particularly suitable for applications where light shielding properties are required. Further, since it has pores, its heat conduction efficiency is lower than that of ordinary thermoplastic resin, and it is particularly suitable for applications requiring heat insulation and heat retention such as labels for hot beverages. In addition, since it has pores, it has excellent cushioning properties, and it is also suitable for protection purposes such as fragile, fragile and fragile items.

[0199] Since the second pore-containing film is excellent in printability, light shielding properties, high rigidity, fracture resistance, shrinkage finish properties, etc. of the film, its use is not particularly limited. If necessary, it can be used as various molded products such as plastic bottles such as blow bottles, trays, lunch boxes, prepared food containers and dairy products containers by forming printed layers, vapor deposition layers and other functional layers. Such a molded product can be manufactured using a general method for manufacturing a molded product.

[0200] In addition, the second pore-containing film can be used as a heat-shrinkable label for food containers such as PET bottles and glass bottles for soft drinks and foods. Even a complicated shape such as a round cylinder, square prism, pentagonal column, hexagonal column, etc., can be adhered to the shape by heat shrinking, and a container with a beautiful label without avatar Can be obtained. As a heat shrinking method for performing such mounting, a general heat shrinking method can be used. The resulting molded product can be used as a container or the like.

[0201] The molded article and container of the present invention can be produced by using a normal molding method.

[0202] The second pore-containing film has excellent low-temperature shrinkability and shrink-finishing properties. Therefore, when used as a heat-shrinkable label, the heat of a plastic molded product that causes deformation when heated to a high temperature. It can be suitably used as a heat-shrinkable label for a package made of a material that is very different from the heat-contractible pore-containing film of the present invention in terms of thermal expansion coefficient and water absorption. Examples of the material forming the package include metal, porcelain, glass, paper, polyethylene, polypropylene, polybutene and other polyolefin resin, polymethacrylate resin, polycarbonate resin, polyethylene, and the like. Examples include those using at least one selected from polyester-based and polyamide-based resins such as terephthalate and polybutylene terephthalate as constituent materials.

[0203] Further, as a material constituting the package in which the second pore-containing film can be used as a heat-shrinkable label, in addition to the above-mentioned resin, polystyrene, rubber-modified impact-resistant polystyrene (HIPS) ), Styrene-butyl acrylate copolymer, styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, acrylonitrile butadiene styrene copolymer (MBS), polysalt-bulb resin, phenol resin, urea Examples of the resin include cocoa resin, melamine resin, epoxy resin, unsaturated polyester resin, and silicone resin, and may be a mixture of two or more of these, or a laminate. Example

[0204] Hereinafter, the present invention will be described in detail with reference to experimental examples and comparative examples, but the present invention is not limited thereto.

The physical property values and evaluation in the experimental examples and comparative examples were measured and evaluated by the following methods. Here, the direction of film take-up (flow) is described as MD, and the direction perpendicular to it is described as TD.

[Melt flow rate (MFR)]

Using a melt indexer (120S AS-2000) manufactured by Yasuda Seiki Seisakusho, the melt flow rate of the polyolefin resin composition was measured in accordance with JIS K7210 (measurement temperature: 230 ° C, load: 21.18N).

[0206] [Dynamic viscoelasticity measurement (Ε ')]

A film with a thickness of 200 μm was prepared using polyolefin resin using a hot press (made by Shinfuji Metal Industry Co., Ltd.), then cut into a size of 4 mm x 60 mm, and a viscoelasticity spectrometer (IT measurement ( Co., Ltd .: DVA-200), chuck 2.5 cm, vibration frequency 10 Hz, strain 0.1%, heating rate 1 ° CZ min., Measuring temperature 40 ° C to 150 ° C in the longitudinal direction Measurement was made in the direction (side length 60 mm), and the storage modulus at 80 ° C was measured.

[Particle size of polyolefin resin composition]

The obtained film was cut into a size of TDlOmm X MDlmm X thickness 80 μm with a microtome, and the dispersed domain shape at the center of the film thickness was observed at 10 locations with an electron microscope, and the average value of the maximum width in the flow direction was determined as the major axis. The average value of the maximum width in the thickness direction of the dispersion domain was calculated as the minor axis.

[0208] [Aspect ratio]

The obtained film was cut into a size of TDlmm x MDIOmm with a microtome, and observed at 10 locations with an electron microscope. The aspect ratio of the domain (major axis Z) with component (B) incompatible with component (A) in the film. The minor axis was calculated.

[0209] [Printability] Using a bar coater, apply a special gravure ink OS-M (indigo) manufactured by Dainichi Seika Kogyo Co., Ltd. to a film obtained by appropriately diluting with a solvent. Judgment was made based on the above criteria.

◯: The ink is uniformly applied without unevenness.

Δ: There is unevenness on the ink application surface, and there are places where the ink is applied.

X: Ink is hardly applied.

[0210] [Ink adhesion]

After applying the ink to the ink-coated film obtained in the above printability test, a sero tape (Elpac LP-18, manufactured by Nichiban Co., Ltd.) is applied to the coated surface after 1 minute, and it is rubbed 5 times with a finger. Immediately thereafter, the cellophane tape was peeled off at once, and the amount of ink peeled off was visually observed. Evaluation was performed according to the following criteria.

◯: There is no peeling of ink.

Δ: Some peeled but remained! /, More parts.

X: Completely peels off.

[0211] [True specific gravity]

The true specific gravity of the used fat is dl, (12 (g / cm ³ ), the mass part of each is rl, Γ2, and the true specific gravity (gZcm ³ ) is Calculated.

True specific gravity = (dlXrl + d2Xr2 + '' ') Z (rl + r2 +'-')

[0212] [bulk specific gravity]

The obtained film was accurately cut into a size of MDlOcmXTDlOcm, and the mass w (g) was measured. The thickness t (m) at 50 points of the film was measured, and the bulk specific gravity (g / cm3) was calculated by the following formula. Calculated.

Bulk specific gravity = (wZt) X100

[0213] [Liquid specific gravity separation (bulk specific gravity after heat shrinkage)]

After the measurement target film was 25% shrinkage at 80 ° C, and fine power base crushed into pieces MDlcmXTDlcm, whether power float floated in water (i.e., bulk specific gravity is less than 1. OOg / cm ³ No) was determined according to the following criteria.

○: When everything floats Δ: When there is something floating and sinking, or when there is something floating in the water

X: When everything sinks

[0214] [Fracture resistance 1]

In order to evaluate the film manufacturing process and the fracture resistance during use, the following measurements were performed.

The obtained film was cut into MD110mmXTD15mm strips, and the tensile elongation at MD of the film at an ambient temperature of 0 ° C was measured at a chucking distance of 40mm and a tensile speed of lOOmmZmin according to JIS K 6732. The average value of the measured values is shown in the table.

[0215] [Rupture resistance 2]

The obtained film was cut into a size of MD100mmXTD4mm, and the tensile elongation in the MD direction of the film at an ambient temperature of 0 ° C was measured at 1 OOmmZmin according to JIS K 7127. The value was determined. Those with an elongation exceeding 150% were evaluated as ◯, those with 100% or more and less than 150% were evaluated as △, and others were evaluated as X.

[0216] [Fracture resistance 3]

In order to evaluate the manufacturing process of the film and the fracture resistance during use, the following measurements were performed. The obtained film was cut into a size of MD110mmXTD15mm, and in accordance with JIS K 6732, at a tensile speed of 200mmZmin, at an ambient temperature of 23 ° C, at a tensile speed of lOOmmZ min, at an ambient temperature of 0 ° C, the tensile elongation at MD The average value of 10 measurements was shown in the table.

[0217] [Heat shrinkage]

The obtained film was cut into a size of MDlOOmmXTDlOOmm, immersed in an 80 ° C hot water bath for 10 seconds, and the amount of shrinkage was measured. For thermal shrinkage, the larger value of MDZTD, which is the ratio of shrinkage to the original size before shrinkage, is expressed as a percentage.

[0218] [Tensile modulus 1]

In order to evaluate the rigidity of the obtained film, the following measurements were performed.

The obtained film was cut into a size of MD400mmXTD5mm and measured according to JIS K7127 in the direction perpendicular to the main shrinkage direction (MD) of the distance between chucks of 300mm, tensile speed of 5mmZmin, and ambient temperature of 23 ° C. did. [0219] I-tension elastic modulus 2]

The obtained film was cut into a size of MD5mm x TD400mm, and a tensile test was performed at a test speed of 5. OmmZ at a temperature of 23 ° C with a chuck spacing of 80. Omm, and the first straight line of the tensile stress strain curve. Using the part, it was calculated by the following formula.

Ε = σ / ε

Ε: Tensile modulus

σ: Difference in stress per unit area (average cross-sectional area of sample before tensile test) between two points on a straight line

[0220] [Tensile modulus 3]

The obtained film was cut into a size of MD100 mm X TD4 mm and measured in the direction (longitudinal direction) perpendicular to the main shrinkage direction of the film at a temperature of 23 ° C according to JIS K 7127.

[0221] [Shrink finish]

A film printed with a grid of 10 mm intervals was cut into a size of MD100 mm X TD298 mm, and both ends of the TD were overlapped 10 mm and bonded with a solvent to form a cylinder. This cylindrical film was attached to a 500 ml PET bottle and passed in about 4 seconds without rotating through a steam heating type 3.2 m (3 zone) shrink tunnel. The tunnel ambient temperature in each zone was adjusted to 80 to 90 ° C by adjusting the amount of steam with a steam valve. The film passed through was evaluated visually by the following criteria.

A: Shrinkage is sufficient, and there is no wrinkle, fluttering, or lattice distortion, and adhesion is good.

〇: Shrinkage is sufficient force Wrinkle, fluttering, force with slight distortion of lattice, or shrinkage in the vertical direction is noticeable, but there is no practical problem.

X: Insufficient lateral shrinkage or longitudinal shrinkage is conspicuous and causes a practical problem.

[0222] [Natural contraction rate 1]

Cut the resulting film to MDlOOmm X TDlOOOmm size, leave it in a thermostatic chamber at 30 ° C for 30 days, measure the amount of shrinkage relative to the original size before shrinkage in the main shrinkage direction, and set the ratio as% Displayed by value. [0223] [Natural contraction rate 2]

Cut the resulting film to MDlOOmmXTDlOOOmm size, leave it in a constant temperature bath at 30 ° C for 30 days, and measure the length after shrinkage relative to the original size before shrinkage in each direction. The higher ratio was obtained as the natural shrinkage rate. If this natural shrinkage was 1.5% or less, it was evaluated as ◯, if it exceeded 1.5% and 3.0% or less, it was evaluated as △, and if it exceeded 3.0%, it was evaluated as X.

[0224] [Light transmittance 1]

The obtained film was cut into a size of MD50 mm XTD 50 mm, and a spectrophotometer (“U-4000”, manufactured by Hitachi, Ltd.) with an integrating sphere attached was used. The light transmittance was measured at, and X was evaluated when the maximum value of the light transmittance exceeded 50%, ○ was evaluated when it was 50-25%, and ◎ was evaluated when it was less than 25%.

[0225] [Light transmittance 2]

The light transmittance at wavelengths of 315 nm and 550 nm and the maximum light transmittance between 240 nm and 800 nm were measured by the method of light transmittance 1 described above.

[0226] [Measurement of thermal insulation]

The obtained film was cut into a size of MD98 mm XTD 208 mm and coated on a metal can (Toyo Seikan Co., Ltd .: TEC200) coated with the film of the present invention so that the shrinkage rate was 20% at 65 ° C. 190 mL of hot water was poured, immediately held with bare hands, and the number of seconds that could be kept without feeling the heat was measured and evaluated as follows.

Calculate the average number of seconds measured by three measurers (25-year-old male, 25-year-old female, 35-year-old male). If the value is 30 seconds or more, 〇, and if it is less than 30 seconds, X did. Those that could last longer than 60 seconds were evaluated as 60 seconds.

[0227] The raw materials used in the examples and comparative examples are as follows.

((A) component)

• Polylactic acid-based rosin-made by Nature Works LLC Product name: NatureWorks4050, L-form ZD-form weight = 95Z5, hereinafter abbreviated as “PLA1”. • Polylactic acid-based rosin-made by Nature Works LLC Product name: NatureWorks4060, L-form ZD-form weight = 88Z12, hereinafter abbreviated as “PLA2”.

• Polylactic acid-based fats-Polylactic acid-based fats manufactured by Nature Works LLC "Nature Works 4050D (L: D: 95Z5, weight average molecular weight 200,000, hereinafter abbreviated as" PLA3 ". Fatty acid: Polylactic acid based fat oil manufactured by Cargill 'Dow, Inc. Nature Works 4060D (L form: D form = 88Z12, weight average molecular weight 200,000, hereinafter abbreviated as “PLA4”.

[0228] (Component (B))

'Polypropylene resin: manufactured by Nippon Polypro Co., Ltd. Product name: Novatec FY6H (elastic modulus at 80 ° C = 0.72GPa MFR = 1.9gZlO), hereinafter abbreviated as "P01".

• Polypropylene resin: manufactured by Nippon Polypro Co., Ltd. Product name: FL6H, hereinafter abbreviated as “P02”. 'Polypropylene resin: Made by Nippon Polypro Co., Ltd. Product name: FB3HAT, hereinafter abbreviated as “P03”.

[0229] (Component (C))

• Aliphatic polyesters other than polylactic acid resin: Showa High Polymer Co., Ltd. Trade name: Biono Ile 3003, Polybutylene succinate 'adipate copolymer, Storage elastic modulus at 23 ° C = 3. 9 2 X 10 ⁸ Pa, hereinafter abbreviated as “BN1”.

.Polybutylene succinate resin: Showa High Polymer Co., Ltd. Trade name: Pionore, hereinafter abbreviated as “BN 2”.

'Polyethylene polyacetate butyl copolymer ... manufactured by Dainippon Ink & Chemicals, Inc. Product name: Enoslene 260, storage elastic modulus at 23 ° C = 2. 42 X 10 ⁷ Pa, hereinafter abbreviated as "EVA" .

• Lactic acid-based copolymer: manufactured by Dainippon Ink Co., Ltd. Product name: Bramate PD150, hereinafter abbreviated as “PD1 50”.

'Core-shell structure acrylic silicone copolymer… Made by Mitsubishi Rayon Co., Ltd. Product name: Metabrene S2001, (hereinafter abbreviated as “S2001”).

• Lactic acid copolymer with Tg of 0 ° C or less: Product name GS—PLA AD92W manufactured by Mitsubishi Chemical Corporation, hereinafter abbreviated as “AD92W”.

[0230] (Component (D))

'Oxidized titanium: DuPont's product name: R108, hereinafter abbreviated as “FL1”. • Barium sulfate: manufactured by Sakai Chemical Co., Ltd. Product name: B-55, hereinafter abbreviated as “FL2”.

[0231] (Other additives)

'Inorganic particles: manufactured by Shiraishi Calcium Co., Ltd. Trade name: Opti White, special calcined kaolin clay, hereinafter abbreviated as “inorganic particles”.

[0232] <Manufacture of laminated film>

(Example 1)

As shown in Table 1, 100 parts by mass of “PLA3” as component (A) used in layer (I) and 30 parts by mass of rpoij as component (B) were dry blended, and 40 mm φ manufactured by Mitsubishi Heavy Industries, Ltd. The mixture was kneaded at 200 ° C and lOOrpm using a small unidirectional twin-screw extruder, extruded into a strand shape, quenched in a water tank, and then cut to produce pellets.

As the resin composition used for the (II) layer, 50 parts by mass of the above-mentioned “PLA3” and 50 parts by mass of “PLA4” were dry blended, and pellets were produced by the above-described method.

The obtained pellets are put into separate single screw extruders manufactured by Mitsubishi Heavy Industries, Ltd., melt-mixed at a set temperature of 200 ° C, then co-extruded from two types of three-layer dies, and cast at 60 ° C. It was taken up and cooled and solidified to obtain an unstretched laminated sheet. The film was then stretched 4.0 times in the transverse uniaxial direction at a preheating temperature of 75 ° C and a stretching temperature of 72 ° C using a film tenter manufactured by Kyoto Machine Co., Ltd. A shrinkable pore-containing film was obtained. Table 1 shows the measurement and evaluation results of the obtained film.

[0233] (Example 2)

As shown in Table 1, a heat-shrinkable pore-containing film was obtained in the same manner as in Example 1, except that the amount of “P01” added in Example 1 was changed to 60 parts by mass.

About the obtained film, the same measurement and evaluation as Example 1 were performed. The results are shown in Table 1.

[0234] (Example 3)

As shown in Table 1, in Example 1, when the unstretched laminated sheet was prepared, the aspect ratio was changed by adjusting the lip gap of the die and the take-up speed of the cast roll. Thus, a heat-shrinkable pore-containing film was obtained.

About the obtained film, the same measurement and evaluation as Example 1 were performed. The result Table 1 shows.

[Example 4]

As shown in Table 1, in Example 1, the (A) component in the (I) layer was mixed with 80 parts by mass of “PLA3” and 20 parts by mass of “PLA4”, and the component (B) Was changed to 20 parts by mass of `` P02 '' and the resin composition used in the layer (Π) was changed to 100 parts by mass of `` PLA1 '', and heat shrinkage was performed in the same manner as in Example 1. A characteristic void-containing film was obtained.

[0236] (Comparative Example 1)

As shown in Table 1, in Example 1, the content of “P01” is changed to 20 parts by mass, and the lip gap of the die and the take-up speed of the cast roll are adjusted when producing an unstretched laminated sheet. A heat-shrinkable Finolem was obtained in the same manner as in Example 1 except that the aspect ratio was changed by.

[0237] (Comparative Example 2)

As shown in Table 1, a heat-shrinkable film was obtained in the same manner as in Example 1 except that the amount of “P01” added in Example 1 was changed to 5 parts by mass.

[0238] (Comparative Example 3)

As shown in Table 1, a heat-shrinkable film was obtained in the same manner as in Example 1 except that the amount of “P01” added in Example 1 was changed to 100 parts by mass.

[0239] (Comparative Example 4)

As shown in Table 1, in Example 1, a heat-shrinkable pore-containing film was prepared in the same manner as in Example 1 except that the layer (ii) was not formed and a single-layer film (I) was used. Obtained. About the obtained film, the same measurement and evaluation as Example 1 were performed. The results are shown in Table 1.

[0240] (Comparative Example 5)

As shown in Table 1, a heat-shrinkable film was obtained in the same manner as in Example 1 except that in Example 1, the component (B) in the (I) layer was changed to 40 parts by mass of “PO3”.

[0241] (Comparative Example 6)

As shown in Table 1, in Example 1, “BN2” (corresponding to the component (C) that is compatible with the component (A) instead of the component (B) in the (I) layer. ) A heat-shrinkable film was obtained in the same manner as in Example 1 except that 30 parts by mass was added.

[0242] [Table 1]

From Table 1, the film within the range defined by the present invention was excellent in recyclability, rigidity, low-temperature shrinkage, and natural shrinkage with small bulk specific gravity (Examples 1 to 4). On the other hand, when the aspect ratio is out of the range of the present invention, the obtained film is inferior in fracture resistance or does not sufficiently form pores, so the bulk specific gravity is lower than the desired value. Slightly larger and inferior in fracture resistance (Comparative Examples 1 and 5). In addition, when the component (B) in the (I) layer is outside the scope of the present invention, the obtained film does not exhibit sufficient fracture resistance and shrinkage characteristics and forms sufficient pores. As a result, the bulk specific gravity was larger than the desired value (Comparative Examples 2 and 3). In addition, in the case of having no (i) layer, the obtained film was slightly uneven when applying a force ink exhibiting good mechanical properties (Comparative Example 4). In addition, when the resin compatible with the component (A) was used in the (I) layer, the obtained film showed good rupture resistance, but was almost free from pore formation. The bulk specific gravity was larger than the desired value and the natural shrinkage was slightly inferior (Comparative Example 6).

Thus, the film of the present invention has a low bulk specific gravity, excellent recyclability, rigidity, low temperature shrinkability, and natural shrinkage, and heat shrinkability suitable for applications such as shrink wrapping, shrink tying wrapping and heat shrinkable labels. It turns out that it is a void | hole containing film.

(Examples 5-8, Comparative Example 7-: LO)

As the resin for (I) layer shown in Table 2, the components (A) and (B) were dry blended, and a small co-directional twin screw extruder (Mitsubishi Heavy Industries, Ltd., 40 mm φ) was used. The mixture was kneaded at ° C and lOOrpm, extruded into a strand, quenched in a water bath, and then cut to prepare a mixed resin pellet.

In addition, as (Π) layered resin shown in Table 2, components (A) and (C) were dry blended, and mixed resin pellets were produced using the same method as described above.

Each of the obtained pellets is put into a separate single-screw extruder (Mitsubishi Heavy Industries, Ltd.), melted and mixed at a set temperature of 200 ° C, and co-extruded from two types of three-layer die. The unstretched laminated sheet was obtained by taking up with a cast roll and cooling and solidifying.

The film was then stretched 4.0 times in the transverse uniaxial direction at a preheating temperature of 80 ° C and a stretching temperature of 71 ° C by a film tenter (Kyoto Kikai Co., Ltd.), and then rapidly cooled with cold air to heat 80 m thick. A shrinkable pore-containing film was obtained. The evaluation results of the obtained film are shown in Table 2.

Example 7 is the same as Example 5 except that the aspect ratio was changed by adjusting the lip gap of the die and the take-up speed of the cast roll when producing the unstretched laminated sheet. A similar method was adopted.

The stretching temperature in Example 6 was 72 ° C, and the stretching temperature in Comparative Example 1 was 73 ° C.

[0245] [Table 2]

[0246] From Table 2, the film having the composition, heat shrinkage ratio, and aspect ratio defined in the present invention was excellent in break resistance, ink adhesion, and spontaneous shrink resistance.

On the other hand, when the soft component (component C) was not used in the layer (Π) (Comparative Examples 7 and 8), the fracture resistance and ink adhesion were poor. Further, when the aspect ratio was high (Comparative Example 9), the bulk specific gravity was high, and the fracture resistance and shrinkage finish were inferior. In addition, when the DZL ratio of the polylactic acid-based resin in the layer (Π) was high (Comparative Example 10), voids were not generated during stretching, and the bulk specific gravity was large and remarkable.

Thus, the heat-shrinkable film of the present invention has excellent mechanical properties such as heat-shrinkability, rupture resistance, and printing properties, and can reduce the bulk specific gravity and suppress the amount of resin used. I understand.

[Example 9 ~: L 1]

Polylactic acid-based resin composition (組成), polyolefin-based resin composition (Β), and the above soft component (C) were mixed at the mixing ratio shown in Table 3, respectively, and a twin-screw extruder (Mitsubishi Heavy Industries, Ltd. ) Then, melt and mix at a set temperature of 200 ° C, extrude from a die with a set temperature of 200 ° C, take it up with a cast roll at 50 ° C, and cool and solidify it to form an unstretched film with a width of 300 mm and a thickness of 200 m. Obtained.

The obtained unstretched film was stretched 1.05 times at 65-75 ° C by a roll longitudinal stretching machine (Mitsubishi Heavy Industries, Ltd.), and then a film tenter (Mitsubishi Heavy Industries, Ltd.) preheating temperature 80- The film was stretched 4.0 times in the horizontal axis direction at 90 ° C. and a stretching temperature of 65 to 75 ° C. to obtain a heat-shrinkable pore-containing film having a thickness of 80 m.

[Example 12]

100 masses of PLA2 on both sides of the (I) layer consisting of a mixed resin of the polylactic acid-based resin composition (A), the polyolefin resin composition (B), and the soft component (C) shown in Table 3. After forming an unstretched film laminated by coextrusion using a 300 mm width, two-kind, three-layer multi-hold die so as to form the layer (ii) used, the film was stretched by the method described above to obtain a thickness. A heat-shrinkable pore-containing film of 80 m (surface layer 8 mZ intermediate layer 64 mZ back layer 8 m) was obtained.

[0249] (Comparative Examples 11 to 14)

The method described in Example 1, wherein the polylactic acid-based resin composition (A), the polyolefin-based resin composition (B), other inorganic particles, and the soft component (C) were mixed at the mixing ratios shown in Table 3, respectively. In the same manner as above, a heat-shrinkable pore-containing film and a heat-shrinkable film were obtained.

[0250] (Comparative Example 15)

After mixing at the mixing ratio shown in Table 1 and stretching the unstretched film in the same manner as described in Example 1, the film was heat-set in an 80 ° C atmosphere to obtain a pore-containing film.

The following evaluation was performed about the obtained heat-shrinkable void-containing film. The results are shown in Table 3.

[0251] [Table 3] Ingredient Film composition

Actual s example Comparative example

Classification

9 10 11 12 1 1 12 13 14 15

(A) PLA1 (mass part) 100 100 100 100 100 100 100 100 100 Component PLA2 (mass part)

(B) Made ^ P01 (Mass) 30 30 30 30 ― ― ― ― 30

(1) PD150 (mass part) 30 ― ― ― ― 30 ― ― ― Layer (0 ―

Component S2001 (parts by mass) ― 30 ― 15 ― 30 One ―

BN1 (parts by mass) ― 1 30 1 ― ― 1 30 ― Others Inorganic

(Mass) ― ― ― ―

Particle 10 ― One ― ―

(II) Layer PLA2 (parts by mass) ― ― One 100 ― ― ― ― ― Thermal shrinkage (¾) 42 45 50 42 44 48 46 44 1.2 Natural shrinkage 2 (%) 0.4 4 0.4 5 0. 3 0. 2 0. 9 0. 9 0. 8 0. 0 Fracture resistance 2 (%) 270 326 318 390 5. 0 245 481 180 167

Particle size of component (B) (m) 4. 2 1. 9 3. 7 2. 2 ― One ― ― 2. 8 True specific gravity (g / cm ³ ) 1. 18 1. 18 1. 18 1. 20 1 32 1. 22 1. 22 1. 24 1. 16 stations (g / cm ³ ) 1. 04 0. 98 1. 06 1. 04 1. 15 1. 20 1. 21 1. 24 0. 92

88

Bulk specific gravity / true specific gravity 83 89 86 87 99 99 100 79

(¾)

○ ○ ○ ○ ○ X X X ○ Light transmittance 1 31 21 38 22 34 94 97 92 24

(W

○ ◎ ○ ◎ ○ X X X ◎ Thermal insulation ○ ○ ○ ○ ○ X X X ―

[0252] A film having the composition, heat shrinkage rate and storage elastic modulus (Ε '), bulk specific gravity, and particle diameter defined in the present invention from Table 3 was excellent in impact resistance, light shielding properties and heat insulation properties. . On the other hand, when polyolefin resin (resin) and soft component (C) were not used! /, The case (Comparative Example 11) did not satisfy the breaking resistance at all. In the film composed of component (C) (Comparative Examples 12 to 14), since the pores were not generated during stretching, the bulk specific gravity was large, and the light shielding property and heat insulating property were remarkably inferior. In addition, when a soft component was not used and heat setting was further performed (Comparative Example 13), the shrinkage rate was extremely low and it was difficult to use the heat shrinkable label. Furthermore, the heat-set film (Comparative Example 15) which did not contain the soft component (C) had a force with almost no shrinkage.

Thus, the heat-shrinkable film of the present invention has excellent mechanical properties such as heat-shrinkability, impact resistance, light-shielding properties, and heat insulation properties, and can reduce the bulk specific gravity and suppress the amount of resin used. It is a force to be.

[0253] (Examples 13 to 17, Comparative Example 16)

Mixed lactic acid obtained by mixing the polylactic acid-based rosin (Α), polyolefin-based rosin (Β), filler (D) component, soft component (C) component, and other additives shown in Table 4 The twin screw extruder (three Ryoshige Industry Co., Ltd.), melted and mixed at a preset temperature of 200 ° C, extruded from a die with a preset temperature of 200 ° C, taken up with a cast roll at 50 ° C, cooled and solidified, and unstretched sheet Got.

Subsequently, the film was stretched in the transverse direction under the conditions shown in Table 1 using a film tenter (manufactured by Kyoto Machine Co., Ltd.) to obtain a heat-shrinkable film. Table 4 shows the evaluation results of the obtained film.

[0254] [Table 4]

AD92W GSP I a Added as component (C)

[0255] From Table 4, the films of the inventions of Examples 13 to 17 have break resistance, high shrinkage properties, and light shielding function, whereas the film of Comparative Example 1 has insufficient break resistance, and It can be seen that the light transmittance exceeds 40%, and the light shielding property cannot be obtained. In particular, when titanium oxide is used as a filler in the film of the present invention (Examples 13, 14, 15, and 17), the light transmittance at a wavelength of 240 to 40 Onm is suppressed to a very low level, and a good light shielding property is obtained. You can see that Industrial applicability

The film of the present invention has a low bulk specific gravity and excellent printability, high rigidity, rupture resistance, light-shielding properties, and shrinkage characteristics. Therefore, the film, shrink-wrapping, and shrink-binding that require heat shrinkability. It can be suitably used for shrinkage labels, particularly shrink labels.

In addition, since PLA-based coconut resin used in the present invention is plant-derived rosin, it can reduce the environmental burden and is suitable for promoting the use of biomass and aiming for a recycling-oriented society.

Claims

The scope of the claims

[1] A mixed container containing the following component (A) and component (B), wherein the content of component (B) is 5 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of component (A) Stretched at least uniaxially, having at least two layers of (I) layer composed of a fat composition and (II) layer composed of a greave composition mainly composed of the component (A) A film,

In the layer (I), the aspect ratio with respect to the direction perpendicular to the main shrinkage direction of the dispersion domain consisting of the component (B) is dispersed in the matrix having the component force (A) and is not more than 5 and not more than 50. Yes,

A heat-shrinkable pore-containing laminated film having a heat shrinkage ratio in the main shrinkage direction of 20% or more when immersed in warm water at 80 ° C for 10 seconds.

Component (B): Polyolefin with a storage modulus at 80 ° C of 0.25 GPa or more 2. OOGPa or less when measured at a vibration frequency of 10 Hz and a strain of 0.1%, incompatible with component (A) -Based rosin composition

[2] In the layer (I), the DZL specific force of the component (A) 1Z99 ~: L0Z90 or 99Zl ~ 90Z

10 and

2. The heat-shrinkable pore-containing laminated film according to claim 1, wherein in the (Π) layer, the DZL specific force of the (Α) component is 6Z94 to 15Z85 or 94Z6 to 85 Z15.

[3] The layer (ii) contains the following component (C) in addition to the component (A), and the content of the component (C) is 5 parts by mass or more with respect to 100 parts by mass of the component (A). The heat-shrinkable pore-containing laminated film according to claim 1 or 2, comprising a mixed resin composition having a mass part or less.

Component (C): Lactic acid-based polymer whose Tg other than polylactic acid-based resin is 0 ° C or less, aliphatic polyester other than polylactic acid-based resin, aromatic aliphatic polyester, diol, dicarboxylic acid and polylactic acid Copolymer with resin, core-shell structure rubber, ethylene vinyl acetate copolymer, ethylene (meth) acrylate ethyl copolymer, ethylene (meth) acrylic acid copolymer, ethylene (meth) methyl acrylate copolymer A soft component composed of a coagulant or a coagulant mixture comprising at least one selected from a coalesced styrene elastomer

[4] The melt flow rate of the component (B) is 1. OgZlO or more 5.0 4. The heat-shrinkable pore-containing laminated phenolic according to any one of claims 1 to 3, having a gZlO content or less.

[5] The heat-shrinkable pore-containing laminated film according to any one of claims 1 to 4, having a bulk specific gravity of 0.50 or more and less than 1.00.

6. The heat-shrinkable pore-containing laminated film according to claim 5, wherein the bulk specific gravity after heat-shrinking in the range of 25% or less is less than 1.00.

[7] The following (A) component, (B) component, and (C) component are included, and the content of (B) component is 5 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of (A) component And an unstretched film comprising at least one layer of the mixed resin composition, wherein the content of the component (C) is 10 parts by mass or more and 80 parts by mass or less. A film containing heat-shrinkable pores that has been stretched as described above, contains pores, and has a shrinkage ratio in the main shrinkage direction of 20% or more and 80% or less when immersed in warm water at 80 ° C for 10 seconds. .

Component (C): Lactic acid polymer having Tg of o ° c or less other than polylactic acid resin, aliphatic polyester other than polylactic acid resin, aromatic aliphatic polyester, diol, dicarboxylic acid and polylactic acid Copolymer with resin, core-shell structure rubber, ethylene vinyl acetate copolymer, ethylene (meth) acrylate ethyl copolymer, ethylene (meth) acrylic acid copolymer, ethylene (meth) methyl acrylate copolymer A soft component composed of a coagulant or a coagulant mixture comprising at least one selected from a coalesced styrene elastomer

[8] The D, L specific force of the component (A) is 1Z99 to 15Z85 or 99Zl to 85Zl5.

7. The heat-shrinkable pore-containing film according to 7.

[9] The heat-shrinkable hole-containing film according to [7] or [8], wherein the heat-shrinkable hole-containing film has a light transmittance of 50% or less in a range of 240 nm or more and 800 nm or less.

[10] The bulk specific gravity of the heat-shrinkable pore-containing film is 50% or more and 90% or less with respect to the true specific gravity of the resin used in the heat-shrinkable pore-containing film. Description Heat shrinkable pore-containing film.

[11] The maximum axial length force in the minor axis direction of the component (B) dispersed in the heat-shrinkable pore-containing film is not less than 0.1 m and not more than 5 m. Heat shrinkable pore-containing film.

[12] The tensile elongation at break at 0 ° C according to JIS K7127 is 100% or more.

11. The heat-shrinkable pore-containing film described in any one of 11 above.

[13] The heat-shrinkable pore-containing film according to [7] or [8], wherein the component (A), the component (B), and the component (C) further contain a component (D) composed of a filler.

14. The heat-shrinkable pore-containing film according to claim 13, wherein the component (D) is at least one filler selected from the group force consisting of calcium carbonate, barium sulfate, titanium oxide, and zinc oxide.

15. The heat-shrinkable pore-containing film according to claim 14, wherein the component (D) is titanium oxide and has a light transmittance of 20% or less in a wavelength range of 240 nm to 400 nm.

[16] The content of (D) component is 1 part by mass or more and 25 parts by mass or less with respect to 100 parts by mass in total of component (A) and component (B). A heat shrinkable pore-containing finolem.

[17] The light transmittance in the wavelength range of 240 nm to 800 nm is 40% or less, and the contraction rate force in the main shrinkage direction is 0% or more when immersed in warm water at 80 ° C for 10 seconds. Claim 13 The heat-shrinkable pore-containing film according to any one of 1 to 16.

[18] Molding using the heat-shrinkable pore-containing laminated film according to any one of claims 1 to 6 or the heat-shrinkable pore-containing film according to any one of claims 7 to 17 as a substrate

P

PPo

[19] Heat recovery using the heat-shrinkable pore-containing laminated film according to any one of claims 1 to 6 or the heat-shrinkable pore-containing film according to any one of claims 7 to 17 as a substrate. Shrinkable label.

[20] A trough using the molded article according to claim 18 or equipped with the heat-shrinkable label according to claim 19.