CA1270972A - Adhesive resin composition, laminated material using it and resin composition containing it - Google Patents

Abstract

Abstract:
The present invention is directed to an adhesive resin composition useful for bonding a resin having gas barrier properties and a hydrophobic thermoplastic resin.
The composition comprises an ethylene-acrylate or meth-acrylate copolymer grafted with an ethylenic unsaturated carboxylic acid or its acid anhydride; 0.02 to 0.6 equivalent to the ethylenic unsaturated carboxylic acid or its acid anhydride of a Periodic Table group Ia or IIa metal hydroxide; and optionally an ethylene-acrylate or methacrylate copolymer. The invention is further directed to a laminated material of a resin having gas barrier properties and a hydrophobic thermoplastic resin laminated with the adhesive resin composition and a resin composi-tion comprising the adhesive resin composition, a resin having gas barrier properties and a hydrophobic thermo-plastic resin. The laminated material has properties which make it useful in the food packaging industry.

Description

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Adhesive resin com~osition, laminated material using it and resin composition containing it The present invention relates to an adhesive resin composition, a laminated material obtained by laminating a resin having gas barrier properties (particularly a saponified ethylene-vinyl acetate copolymer resin - hereinafter referred to as EVOH) and a hydrophobic thermoplastic resin with the adhesive resin composition, and a resin composition containing the adhesive resin composition.

Recently, the food packaging art has made remarkable technical advances. For example, it is well known that hydrophobic thermoplastic resins, such as saturated polyesters and the like, can be put to practical use in ood packaging to improve the hygienic qualities and the appearance of packages as well as to save weight 1~ as a means o cutting the cost of transport. However, such saturated polyester resins have low gas barrier properties against oxygen, carbon dioxide and the like and, therefore, are not suitable for long-term storage.
Accordingly, glass bottles and metallic cans are predomin-~ antly used, which cause environmental problems, i.e. thedisposal of used cans, increases in costs for recovering used bottles and the like. In view of this, it i5 desired :

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to develop other suitable materials for packaging.
EVOH containing 20 - 55 mole ~ of the ethylene comp~nent has excellent properties for food containers and packaging materials such as good melt molding character-istics, high transparency and excellent gas barrier properties. However, other properties thereof, for example stiffness and resistance to moisture, are disadvantageous an~ unsuitable.
On the other hand, hydrophobic thermoplastic 1~ resins, particularly a saturated polyester resin mainly composed of polyethylene terephthalate, have excellent molding characteristics, a good balance between impact resistance and stiffness, good hygienic qualities and the like. However, as described above, its gas barrier 1~ properties against oxygen, carbon dioxide and the like are insufficient, and its use for food containers and packaging materials is limited.
Therefore, in order to impart both the good gas barrier properties of EVOH and the excellent mechanical ~a properties of a hydrophobic thermoplastic resin, such as a saturated polyester resin, to food containers and packaging materials, lamination of both resins may be considered.
However, these resins have little affinity for each other and it is not possible to obtain a laminated material of both resins by simple thermal adhesion.
Japanese Patent Rokai No. 55-71556 (published May 29, 1980, Nippon Oil) discloses good ` ~`
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~hQsion between a polymer composed of ethylene component-acrylate or vinyl acetate component-ethylenic unsaturated carboxylic acid or its acid anhydride component, and a saturated polye~ter resin. This publication shows that a modified ethylene-carboxyl group containing monomer copolymer, wherein an ethylenic unsaturated carboxylic acid or its aci~ anhydride is chemically bonded to a copolymer composed of ethylene and a carboxyl group containing monomer, such as ethylene-vinyl acetate copolymer or ethylene-acrylate copolymer, has good adhesion to a 3atu~ated polyester resin. The utility thereof is also ~isclosed in the publication.
Japanese Patent I~okai No. 54-101883 published August 10, 1979, Nippon Petrochemical discloses that a thermoplastic resin and EVOH can be laminated by using as an intermediate layer a modified ethylene-carboxyl group containing monomer copolymer, wherein an ethylenic unsaturated carboxylic acid or its acid anhydride is chemically bonded to a copolymer composed of ethylene and ~o a carboxyl group containing monomer. In addition, in Japanese Patent Kokai No. 54-110282 published August 29, 1~79, Nippon Petrochemical, a laminated structure contain-ing EVOH is obtained by using as an adhesive layer a metal combining modified copolymer which is produced by chemi-cally bonding an ethylenic unsaturated carboxylic acid or its acid anhydride to a copolymer composed of ethylene and a carboxyl group containing monomer, and reacting with a metallic oxide or carbonate.
~owever, when a copolymer composed of ethylene i ' . ~

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~7~ 2 component-acrylate component or lower fatty acid vinyl ester component-ethylenic unsaturated carboxylic acid or its anhydride component, or a resin obtained by reaction of such a copolymer with a metallic oxide or a carbonate is used as an adhesive layer in a combination of EVOH and a hydrophobic thermoplastic resin such as a saturated poly-ester resin mainly composed of polyethylene terephthalate, the resul~ing material has low commercial value, while adhesion is effected to some extent. For example, the 1~ laminated material obtained has an inferior appearance due to the formation of streaks, hard spots, wave patterns, etc., the main cause of which is considered to be lack of uniformity in the thickness of a layer of a resin having ~as barrier properties and the formation of a gelled material.
Further, Japanese Patent Kokoku No. 39-6810 published in 1964 discloses a process for preparing an ionic copolymer wherein one or more water soluble ionic metallic compounds are reacted with a copolymer obtained from one or more~ -olefins and one or more~ ethylene type unsaturated carboxylic acids which have one or two carboxyl groups. In this publication, there is described a preferred base copolymer that is obtained by directly copolymerizing ethylene with a monocarboxylic acid monomer ~5 in the presence of or in the absence of an additional co-polymerizable monoethylene type unsaturated monomer. It is also described that, when 10~ or more of the acid group of this base copolymer is neutralized with a metallic ion such as ,. ,: ". ..

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Na and the like, both desired melt flow characteristics as well as desired physical properties in the solid state such as rubber elasticity, flexibility, thermal stability, tenacity, wear resistance and the like can be imparted to the resulting material. This is advantageous to the material obtained in this publication. On the other hand, although it is also disclosed that the base copolymer can be obtained by graft-polymerizing an a-olefin and an acid monomer with a polyolefin base, it is explained that this process is suitable for using a polyolefin obtained from an olefin having a molecular weight larger than that of ethylene, for example, propylene, butene-l, etc., and there is no disclosure that ethylene-acrylate or vinyl acetate copolymer can be used as a polyolein. Further, the invention disclosed in this publication relates to the improvement of physical properties such as those described above in a resin having a melt index (MI) of 0.1 - 100 9~1~ min., and it is disclosed that the resin can be used ~s an adhesive or that for a laminated material, when MI
thereo~ is 100 y/10 min. or more.
However, an ionic copolymer obtained by reacting a copolymer composed of one or more a-olefins and one or more a,~-ethylene type unsaturated carboxylic acids which have one or two carboxyl groups, with one or more water soluble ionic metallic compounds does not exhibit adhesion at all regardless of the presence of acrylate or viny]
acetate component. Furtber~ when~MI is 100 g/10 min. or . . ~
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In Japanese Patent Kokai No. 54-87783 published in 1979~, it is disclosed that, when a polyolefin obtained by modification of a part or all of the polyolefin with at least one monom~r selected from unsaturated carboxylic acids and derivatives thereof is laminated with EVOH, a polyamide resin or a polyester resin, interlaminar adhesion n can ~e improved by incor~orating at least one metallic compound selected from the group consisting of metallic salts of higher fatty acids, metallic oxides, metallic h~droxides, metallic carbonates, metallic sulfates and metallic silicates into at least one layer. The 1~ polyolefin disclosed in this patent publication is a llomopolymer of an ~-olefin such as ethylene, propylene, l-butene, l-pentene, 3-methyl-1-butene, l-hexene, 4-methyl-1-pentene and the like, or a copolymer of at least one monomer and other a-olefins. It is disclosed ~1 that the advantage of the invention disclosed in the publication is remarkably exhibited inter alia in medium or high density polyethylene and polypropylene.
~thylene-vinyl acetate copolymer is also disclosed.
However, in this publication, there is no ~5 disclosure relating to an ethylene-acrylate copolymer and an ethylene-methacrylate copolymer.

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~2~76~ 2 Under these circumstances, the present inventors have intensively studied the relationship between various properties of an adhesive resin, and coextrusion adhesion and molding characteristics on the basis of consideration S of requisite properties for an adhesive resin in industrial coextrusion to obtain a laminated material which has good coextrusion adhesion and good appearance, even in indus-trial coextrusion. As a result, it has been found that a specific modified resin composition is suitable as an 1~ adhesive resin composition, and a laminated material having excellent properties can be obtained by using this adhesive resin composition. Further, it has been found that an intimate blend of a resin having gas barrier properties and a hydrophobic thermoplastic resin can be obtained by lS ~Ising the adhesive resin composition.
One object of the present invention is to provide an adhesive resin composition which shows good interlaminar bonding properties and good molding characteristics, and is ~articularly useful for the lamination of a resin having -~a gas barrier properties and a hydrophobic thermoplasticresin.
According to one aspect of the present invention there is provided an adhesive resin composition which comprises:
~5 an ethylene-acrylate or methacrylate copolymer grafted with an ethylenic unsaturated carb~xylic acid or the carboxylic acid anhydride thereof;~

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0.02 to 0.6 equivalent to the ethylenic unsatur-ated carboxylic acid or its acid anhydride of a Periodic Table group Ia or IIa metal hydroxide;
and optionally an ethylene-acrylate or methacryl-ate copolymer.
In another aspect, the present invention provides a laminated material comprising a resin having gas barrier properties and a hydrophobic thermoplastic resin laminated ~ith the adhesive resin composition.
~n advantage of the present invention, at least in the preferred forms, is that it can provide a laminated material which has both the excellent gas barrier proper-ties of a resin such as EVOH and the excellent mechanical pr~perties of a hydrophobic thermoplastic res~n such as a 1~ saturated polyester resin, a polycarbonate, etc., and can be produced on an industrial scale.
Another advantage of the present invention, at least in the preferred forms, is that it can provide a laminated material useful for food containers and packaging materials.
Still another advantage of the present invention, at least in the preferred forms, is that it can provide a resin composition which is an intimate blend of EVOH and a hydrophobic thermoplastic resin.
In the present invention, both requisite adhesion , ~ , .
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and molding characteristics can be imparted to a coextrud-ing adhesive resin by incorporating a Periodic Table group Ia or IIa metal hydroxide into a modified ethylene-acrylate or methacrylate copolymer having a specific composition in a specific amount. Although the mechanism underlying the invention is not clear, it is considered that these excellent properties may result from an inter-~acial chemical interaction, i.e. a chemical reaction and the like at the interface between a layer of the adhesive resin composition and a hydrophobic thermoplastic resin layer and/or between a layer of the adhesive resin composi-tion and a layer of a resin having gas barrier properties in a coextrusion molding step, particularly at the melting point o~ the resins, due to the incorporation of a Periodic 1~ ~able group Ia and IIa metal hydroxide in a speci~ic range~
This is particularly surprising because this is unpredictable from known techniques such as a modified ethylene-carboxyl group containing monomer copolymer wherein an ethylenic unsaturated carboxylic acid or its

2~ acid anhydride is chemically bonded to a carboxyl group containing monomer such as an acrylatel vinyl acetate, a methacrylate and the like; or a metal combining modified copolymer wherein a metallic oxide or carbonate is reacted with the above modified ethylene-carboxyl group containing monomer copolymer. The composition of the invention is also surprising in that it shows adhesion to EVOH, a : " ' ;: ' ' ;' :~ ' :
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saturated polyester resin and the like and, further, the solid state can be improved by a metallic ion.
In a further aspect of the present invention, there is provided an intimate blend of a resin having gas barrier properties and a hydrophobic thermoplastic resin ~hich contains the adhesive resin composition.
The adhesive resin composition of the first aspect of the present invention comprises:
an ethylene~acrylate or methacrylate copolymer grafted with an ethylenic unsaturated carboxylic acid or its acid anhydride; and 0.02 to 0.6 equivalent to the ethylenic unsatur-ated carboxylic acid or its acid anhydride of a Periodic Table group Ia or IIa metal hydroxide. The adhesive resin composition of the first aspect of the present invention also includes a bend o the resulting metal hydroxide containing composition and an additional ethylene-acrylate o~ methacrylate copolymer.
Examples of the ethylene-acrylate copolymer are ethylene-methyl acrylate copolymer, ethylene~ethyl acryLate copolymer, ethylene-butyl acrylate copolymer, ethylene-n-hexyl acrylate copolymer, ethylene~2-methyl-hexyl acrylate copolymer and the like. Of these, ethylene-ethyl acrylate copolymer is preferred. The content of the acrylate ~
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in view of adhesion and molding characteristics, 10 - 30 ~
by weight is more preferred. The ethylene-acrylate copoly-mer can be prepared by any known method and, usually, that having an MI in the range of 0.01 - 50 g/10 min. and a 5 density of O.92 - O.97 g/cm3 is usedO
Examples of the ethylene-methacrylate copolymer are ethylene-methyl methacrylate copolymer, ethylene ethyl methac~ylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-n-hexyl methacrylate copolymer, ethylene-2-methyl-hexyl methacrylate copolymer and the like. The content of the methacrylate component is preferably 5 - 45 ~ by weight. Particularly, in view of adhesion and molding characteristics, 10 - 35 % by weight is more preferred. The ethylene-methacrylate copolymer can be prepared by any known method and, usually, that having an MI in the range of 0.01 - 50 g/10 min. and a density of 0.92 - 0.97 g/cm3 is used.
Examples of the ethylenic unsaturated carboxylic acid or its acid anhydride used for graft polymerization ~0 include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.
Among them, maleic anhydride is preferred. The amount thereof to be grafted with the ethylene-acrylate or meth-acrylate copolymer is 0.01 - 6 % by weight. In view of adhesion and molding characteristics, 0.1 - 5 % by weight is preferred.
The method used for grafting is not limited to A

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any specific one and includes~ for example, a heat reaction of the ethylene-acrylate copolymer and the ethylenic unsatur-ated carboxylic acid or its acid anhydride in the presence of an organic peroxide compound e.g. dibenzoyl peroxide, dibutyl peroxide, dicumyl peroxide, t-butyl perbenzoate, t-butyl hydroperoxide, cumene hydroperoxide and the like to form a chemical bond between them. The reaction can be carried out in the presence, or in the absence, of a solvent e.g.
benzene, toluene, xylene, chlorobenzene, t-butylbenzene, cumene and the like at 100 - 240C. The reaction is prefer-ably carried out in the presence of a solvent such as toluene, xylene and the like at 110 - 190C since an homo-~enous product can then be obtained.
Examples of the Periodic Table group Ia or IIa metal hydroxide include lithium hydroxide, sodium hydroxide, potas-sium hydroxide, calcium hydroxide, magnesium hydr~xide and the like. Among them, sodium hydroxide is preferred. The amount o the Periodic Table group Ia and IIa metal hydroxide to be added varies depending upon the particular hydroxide used. However, the amount i9 0.02 - 0.6 equivalent, and pre~erably 0.03 - 0.3 equivalent, relative~to the~ethylenic unsaturated carboxylic acid or its acid anhydride grafted.
When the amount is smaller than 0.02 equivalent, it 15 difficult to obtain a desi~red industrially useful molding material due to formation of a wave pattern extending t~rough the entire material, or the ormation of~unevenness.~On the other hand, when the amount l~S larger than 0.6 eqoivalent, ,. :- . . . ...

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tne resulting adhesive resin composition becomes unsuitable as a moldinq material because the composition is colored and/or the fluidity thereof becomes inferior.
The adhesive resin composition of the present S invention comprising the ethylene-acrylate or methacrylate copolymer grafted with the ethylenic unsaturated carboxylic acid or its acid anhydride and 0.02 - 0.6 equivalent rela-tive to the ethylenic unsaturated carboxylic acid or its acid anhydride of the Periodic Table group Ia or IIa metal hydroxide can be preferably used as such but, occasionally, this metal-containing composition is blended with an ethylene-acrylate or methacrylate copolymer. As described above, this blend is also included in the adherent resin composition of the present invention~
1~ In this case, the amount of the metal containing-composition may vary but it is usually present in an amount of 1 - 60 % by weight based on the total weight of the resulting composition. In view of the production costs, molding characteristics and the like, 2 - 40 ~ by weight is preferred.
In the adhesive resin composition of the present invention, other additives which are conventlonal for a thermoplastic resin can be added. Æxamples of such add-itives include antioxidants, ultraviolet absorbers, plas-ticizers, antistatic agents, lubricants, colorants, fillers and the like. These additives can be used as long as the . ~

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, 1l excellent properties o~ the composition are maintained.
Specific examples of the additives are as ~ollows.
Antioxidants: 2,5-di-t-butylhydroquinone, 2,6-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4'-thiobis-(6-t-butylphenol), 2,2'-methylene-bis(4-methyl-6-t-butyl-phenol), tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, 4,4'-thiobis-(6-t-butyl-phenol), etc.
Ultraviolet absorbers: ethyl-2-cyano-3,3-diphenyl-acrylate, 2-(2'-hydroxy^5'-methylphenyl)-5-chlorobenzo-triazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxy-benzophenone, etc.
Plasticizers: dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, phosphate esters, etc.
Antistatic agents: pentaerythritol monostearate, sorbitan monopalmitate, sulfated oleic acid, polyethylene oxide, Carbowax, etc.
Lubricants: ethylene-bis-stearamide, butyl stearate, etc. ~
Colorants: carbon black 7 phthalocyanine, quinacridone, indoline, azo-pigments, titanium 3xide, red oxide, etc.
Fillers: glass fiber, asbestos, mica, ballastinite, * Trade Mark .

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The adhesive resin composition of the present invention can be produced by admixing the desired ingredients according to a conventional method. A known device or apparatus such as a ribbon blender, a high-speed mi~er, a kneader, a mixing roll, Banbury* mixer or an extruder can be used.
Although the MI (JIS K-6760, 190~C, 2,160 g) of the adhesive resin composition thus obtained may vary according to the MI's of the hydrophobic thermoplastic resin and the resin having gas barrier properties to be used for molding, it is preferably 0.2 - 50 g/10 min., more preferably, 0.5 - 30 g/10 min.
In a second aspect, the present invention pro-1~ vides a laminated material comprising a resin having gas barrier properties and a hydrophobic thermoplastic resin laminated by the adhesive resin composition of the present invention.
EXamples of a resin having gas barrier properties ~d suitable for the laminated material of the present inven-tion include EVOH, polyamide resins such as Nylon* 6, Nylon 6-6 and Nylon 6-12 and the like. Particularly, in view of the good molding characteristics and gas barrier properties, it is preferred to use EVOH having an ethylene ~5 component content of 20 - 55 mole ~ and a saponification degree of not less thah 90 %. ~urther, a modified resin * Trade mark , ..; , "~ - . - :

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obtained by treating the above EVOH with a boron compound such as boric acid or borax, or by copolymerizing a copoly-merizable third component together with ethylene and vinyl acetate and then saponifying the resultant product, also has melt molding characteristics and, in so far as gas barrier properties are maintained, it can also be used as the resin having gas barrier properties.
The hydrophobic thermoplastic resin can be any re~in having heat melt moldability. Preferred examples of a the resin include saturated polyester, polycarbonate, poly-vinyl chloride, polystyrene, shock-resistant polystyrene, polyethylene, polypropylene, ethylene-vinyl acetate copoly-mer, ethylene-acrylate copolymer and the like. Of these, the saturated polyester and the polycarbonate are the most preferred. When EVOH is used as the resin having gas barrier properties, it is possible ~o use a polyamide resin such as Nylon 6, Nylon 6-6 or Nylon 6-12 as the hydrophobic thermoplastic resin.
The saturated polyester is a condensation polymer o~ a dicarboxylic acid and a diol component. Examples of the dicarboxylic acid are terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and the like. These dicarboxylic acids can be used alone or in combination.
Further, a small amount oE adipic acid, sebacic acid or the like can be used in combination with the above dicarboxylic acids. Examples of the diol component include ethylene glycol, butylene glycol, hexylene glycol, cyclohexane - ,.
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dimethanol and the like. They can be used alone or in combination. Further, as a minor component, a small amount of diethylene glycol, polytetramethylene glycol, penta-erythritol, bisphenol A and the like can be used in combina-tion with the above diol components. In particular, it is preferred to use terephthalic acid as the dicarboxylic acid component in an amount of not less than 70 mole % because the properies of the molded product obtained such as trans-parency, mechanical properties and the like, are improved.
10 Although the polymerization degree of the saturated polyester is not specifically limited, it is preferred to use a satur-~ted polyester having [n] (dl/g) of 0.3 - 2.0 determined in a mixed solvent of phenol/tetrachloroethane (50/50) at 30C.
An aromatic polycarbonate is preferred as the 1~ polycarbonate. The aromatic polycarbonate is a polymer or copolymer obtained by reaction of a dihydroxyaryl compound with pho~gene, diphenyl carbonate or the like. Examples of the dihydroxyaryl compound include bisphenol A, bis(4-hydroxyphenyl)methane, l,l-bis(4-hydroxyphenyl)ethane, 2,2-bi~t4-hydroxyphenyl)butane, bis(4-hydroxyphenyl)phenyl-methane, 2,2-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-hydroxydiphenyl ether, 4,4'-dihydroxyphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone and the like. They can be ~5 used alone or in combination thereof. Optionally, hydroquinone, resorcinol and the like can be appropriately polymerized in addition to the above dihydroxyaryl "` : ;

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compounds.
Representative of the polycarbonates is a polymer obtained by the reaction of bisphenol A with phosgene, and having [n] (dl/g) of 0.1 - 1 determined in methylene S c~lloride at 20Co The laminated material of the present invention is obtained by laminating a resin having gas barrier properties and a hydrophobic thermoplastic resin with the adhesive resin composition of the present invention. The 1~ construction of the laminated material is, for example, a three layered strucSure of three resins such as B/A/C, a three or five layered symmetrical or asymmetrical structure o~' three resins such as BtA/C/A/B, C/A/B/A/C, B/A/C/A/B' or C~A~B/A/C' (wherein B and B' are the resins having gas 1~ barrier properties; A is the adhesive resin composition; and C and C' are the hydrophobic thermoplastic resins) or other multi-layered structure of B, A and C wherein at least one o~ A, B and C is layered to each other such as B/B/A/C, B~A/C~C or B/B/A/C/C.
The laminated material o~ the present invention can be produced by a known method, for example, lamination within a die, thermal adhesion with a laminating press outside of a die, and the like. Lamination within a die (coextrusion) is preferred. Extrusion molding with a T-die ~' or a ring die is more preferred. Further, direot blow molding and injection blow molding are also applicable.
The laminated material thus obtained has both good , :-. :` ' ~ . . :.

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gas barrier properties and excellent mechanical properties and, therefore, it is useful for food containers (e.g., cups and bottles) and packaging material. Further, by subjecting it to uniaxial or biaxial orientation, deep draw, blow molding and the like, the utility of the laminated material can be enhanced. In addition, the laminated material of the present invention can be further laminated with one or more other sheet materials such as a synthetic resin film, metal ~oil, paper and the like.
In a third aspect, the present invention also provides an intimate blend comprising the adhesive resin composition of the present invention, the above EVOH and the ab~ve hydrophobic thermoplastic resin.
That i3, when the laminated material of the present 1~ invention or a trimmed part thereof which contains the above EVOH as the resin having gas barrier properties is recovered ~or re-use, a blend of the adhesive resin composition com-prising the present invention (A), EVOH ~B) and the above hydr~phobic thermoplastic resin (C) results.
~a It is known that a blend of EVOH (B) and the hydrophobic thermoplastic resin (C) has excellent character-istics. However, in general, such a composition has inferior homogeneity and inferior molding characteristics. Therefore, when it is molded into film, sheet, bottle and the like by extrusion molding, a disuniform phase of separated foreign matter, or gel from an insolubilized resin, particalarly, EVOH is liable to form. It is known that, when the operation .,~

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time is longer, such foreign matter increases and, thus, the appearance of the resulting molded product is impaired.
Accordinqly, although a blend of EVOH and the hydrophobic thermoplastic resin has excellent characteristics, in practicer extrusion molding is not applicable or, even i~
extrusion molding were applicable, the operation time would h~ve to be very short.
Thus, it is very difficult to re-use a recovered laminated material obtained by coextrusion of EVOH and the hydrophobic thermoplastic resin.

Nevertheless, when molding is carried out by using a recovered material comprising the above ingredients (A), IB) and (C), or a freshly prepared blend composition compris-ing the ingredients (A), (B) and (C) according to the present ~5 invention, the inferior homogeneity and inferior molding characteristics of a mixture of EVOH and the hydrophobic thermoplastic resin are remarkably improved and a coextruded product having a beautiful appearance or a molded product having ~ood gas barrier properties and excellent mechanical properties can be obtained.
Although it is preferred to use the above adhesive resin composition as the ingredient (A) in the blend of the present invention, the Periodic Table group Ia or IIa metal hydroxide used in the adhesive resin composition may be ~5 replaced by a salt or oxide of the metal such as, for example, sodium carbonate, lithium carbonate, magnesium :. . .,:: : ::
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carbonate, sodium actate and the like. Further, the ethylene-acrylate or methacrylate copolymer used in the adhesive resin composition may be replaced by an ethylene-vinyl acetate copolymer such as that having a vinyl acetate component content of 5 to 50 % by weight, and preferably, in view of the resulting homogeneity and desirable molding characteristics, 10 - 40 ~ by weight. These compositions are also included in the scope of the present invention.
Thus, the ingredient (A) used in this aspect of the present invention comprises:
an ethylene-acrylate, methacrylate or vinyl acetate copolymer grated with an ethylenic unsaturated carboxylic acid or its acid anhydride; and 0.02 to 0.6 equivalent to the ethylenic unsaturated 1~ carboxylic acid or its acid anhydride of a Periodic Table group Ia or IIa metal hydroxide 9 salt or oxide. The ingredient (A) may also be a blend of the metal compound-containing modified resin and an ethylene-acrylate, meth-acrylate or vinyl acetate copolymer.
2a The amount oE each ingredient (A), (B) or (C) in the blend of the present invention ;s not limited to a specific range and it can optionally be chosen according to the particular use of the composition. However, from a practical point of view, it is important that the ratio oE the hydrophobic thermoplastic resin (C) to EVOH having an ethylene component content of 20 - 55 mole ~ and a saponification degree of not less than 90 ~ (B) ~ :

be such that the amount o~ either resin is larger than that of the other to impart characteristic properties such as excellent mechanical properites or good gas barrier properties to the composition.
S Examples of the composition containing a larger amount of the hydrophobic thermoplastic resin include that having a weight ratio of the hydrophobic thermoplastic resin (C) : EVOH (B) of 60 : 40 - 99.9 : 0 1~ particularly, 70 :
30 - 99.7 : 0.3. On the other hand, examples of the l~ composition containing a larger amount of the resin (B) include those having a weight ratio of the hydrophobic thermoplastic resin (C) : EVOH (B) of l : 99 - 40 : 60, particularly, 5 : 95 - 30 : 70.
The amount of the ingredient (A) in the blend lB of the present invention is chosen so that the homogeneity of the composition is improved while maintaining the desired properties of the composition such as mechanical properties, transparency and gas barrier properties. In many cases, the amount of the ingredient (A) is 0.1 - 50 2a parts by weight~ particularly, 1 to 30 parts by weight per 100 parts by weight of the sum o~ the weights of the hydrophobic thermoplastic resin (C) and EVOH (B) ((C) ~
~B)). When the amount of the ingredient (A) exceeds 50 parts by weight, the properties such as mechanical ~5 properties, transparency and gas barrier properties of the composition mainly composed of the hydrophobic thermoplastic resln (C) and EVOH (B) o, the present in~ention are liable 7~

to be impaired. On the other hand, when the amount of the ingredient (A) is lower than 0.1 part by weight, the homogeneity sometimes becomes insufficient depending upon the particular combination of the hydrophobic thermoplastic resin (C) and EVOH (B).
There is no limitation on the method for blending these three ingredients (A), (B) and (C) to obtain the intimate blend composition of the present invention. For example, the three ingre~ients can be dry blended, or the ingredient (A) can be previously admixed with a part or all of either the hydrophobic thermoplastic resin (C) or EVOH
(B).
Although the mechanism by which the ingredient (A) remarkably improves the homogeneity and molding character-1~ istics of EVOH (B) and the hydrophobic thermoplastic resin(C) is not fully clear, it is presumed that the ingredient (A) effectively acts by a complicated combination of rheological effects, chemical action and the like in the melt system of EVOH (B) and the hydrophobic thermoplastic ~0 resin (C).
In the composition comprising ingredients (A), (B) and (C), when an ethylen.e-acrylate copolymer is used as the hydrophnbic thermoplastic resin ingredient tc), it is necessary to use the copolymer suitable for a molding ~5 material and having an acrylate content lower than that of the ethylene-acrylate copolymer in the ingredient (A).

, ~

~27~97'~

Likewise, when an ethylene-vinyl acetate copolymer is used as the hydrophobic thermoplastic resin ingredient (C), it is necessary to use the copolymer suitable for a molding mater-ial and having a vinyl acetate content lower than that of the ethylene-vinyl acetate copolymer in the ingredient (A).
The resin composi~ion of the present invention comprising the ingredients (A), (B) and (C) can be also used as one layer of a multi-ply structure. In particular, when the multi-ply structure is M/E/M, M/D/E, M/D/E/D/M, 1~ P/D/E/D/M, P/E/P/M, P/M/D/E/D/M/P, P/M/D/E/D/P and the like (wherein P is a hydrophobic thermoplastic resin layer; E is a layer of EVOH having an ethylene component content of 20 -55 mole % and a saponification degree of not less than 90 %;
D is an adhesive resin layer; and M is the blend of the present invention comprising the ingredients (A), (B) and (~)), a beautiful molded product having good homogeneity and excellent molding characteristics can be obtained~ In this case, it is effective to use the above adhesive resin composition (A) of the present invention as the adhesive ~a ~esin layer D. In such a multi-ply molded product, the composition oE the present invention comprising (A), (B) and (~) may not only be scrap material, but may also be a freshly prepared composition formed by blending the respective ingredients (A), (B) and (C). The method for producing the ~5 multi-ply product is not speciFically limited. For example, so-called coextrusion molding can be employed, which is car-ried out by using extruders, the number of which corresponds :
. .. , .

~27~

to the number of the kinds of resins to be used, coextruding the molten resins in such a laminar state that the flows of molten resins laminate together and mold the resins into a multi-ply product. Other multi-ply molding methods such as extrusion coating, dry lamination and the like can also be employed. Further, by subjecting a molded product of the blend of the present invention or a multi-ply molded product containing the blend to uniaxial or biaxial orientation, ~ap draw, blow molding and the like, the utility of the l~ product can be enhanced. In addition, the laminated product thus obtained can be further laminated with one or more other sheet materials such as synthetic resin film, metal foil, paper and the like.
A molded product made by using the blend lS composition of the present invention has various desirable properties such as high strength characteristics and good gas barrier properties due to the homogeneity of the blend, and is very valuable from an industrial point of view.
The following Examples and Comparative Examples ~urther illustrate the present invention but are not to be construed to limit the scope thereof. In the Examples and comparative examples, all "parts" and l'percentages" are by weight unless otherwise stated.
Examples_l - 4 ~S An ethylene-ethyl acrylate copolymer (215 parts) - : . : . :, - ::: , ... ....
:. "..-;..~ :; :.: :,: :

.. ~- .,,; , .::

~;~7~97~

having the ethyl acrylate component content Or 25 %, MI
(190C, 2,160 g) of 6.3 g/10 min., the density Or 0.936 g/cm3 and the melting point of 70C, and maleic anhydride (1.8 parts) were dissolved in purified toluene (648 parts) and the solution was maintained at 180C. To the solution was continuously added a puri~ied toluene solution (180 parts) of maleic anhydride (5 parts) with stirring over 2 hours. Concurrently, a purified toluene solution (100 parts) Ol' cumene hydroperoxide (1.0 part) was also l~ continuously added over 2 hours. Rfter completion of the addition, the reaction was continued for an additional 30 min. After cooling, the reaction mixture was p~ured into a large amount of methyl alcohol to precipitate a polymer.
The polymer obtained was reprecipitated by using purified toluene as a solvent and methyl alcohol as a non-solvent.
The resulting polymer contained 1.5 ~ of maleic anhydride and had MI of 4.3 g/10 min.
An aqueous solution containing a predetermined amount of sodium hydroxide was homogeneously admixed with the polymer thus obtained. After partial drying, the mixture was molten, kneaded and pelletized by using a vent extruder under reduced pressure whiledischarging volatiles to obtain an adhesive resin composition comprising a modified copolymer.
A predetermined amount of the adhesive resin composition thus obtained was dryblended with the above ethylene-ethyl acrylate copolymer and then made molten kneaded ~; :

., , : ::
::.. ; : -;;"`' ~
: ~, : :

7~?~57~

and pelletized by using an extruder to obtain an adhesive resin blend.
By using EVOH obtained by saponification of 99.6 %
of the vinyl acetate segment oP an ethylene-vinyl acetate copolymer having the vinyl acetate component content of 67 mole ~ which had [nl of 1.11 (in a mixed solution of phenol/water ~85/15), 30~C, dl/g) as a resin having gas barrier properties, and by using a saturated polyester obtained by polycondensation of terephthalic acid as the dicarboxylic acid component thereof and ethylene glycol as the diol component thereof which had [n] of 0.67 (in a mixed solution of phenol/tetrachloroethane (50/50), 30C, dl~g) as a hydrophobic thermoplastic resin, laminate materials were produced as follows.
1~7 A feed block type coextruding apparatus for five layers of three kinds of resins was used. This apparatus had an extruder I having the inner diameter of 120 mm¢7 , an extruder II having the inner diameter of 60 mm7~7 and an extruder III having the inner diameter of 90 mm¢ . In the extruders I and II, each molten material was extruded in two separated layers. The two layers fro7m the extruder II were layered on both surfaces of a layer of a resin molten and extruded from the extruder III, respectively, and successively the two layers from the~extruder I were layered ~5 on both surfaces of the resulting layered material. The hydrophobic thermoplastic layer (C), the adhesive resin -composition (A) and the resin having~gas barrier properties ::. ::. ::~: ::::

~ , , ,. ,:

7~

(B) were fed to the extruders I, II and III, respectively, and a laminated sheet having 5 layers o~ three kinds of resins, C/A/B/A/C ( 400 ~/50 ~/50 ~/50 ~/400 ~ ) was produced by coextrusion at the die temperature of 260C and at the take-off speed of 4 m/min. The sheet was deep drawn by using an infrared heating-vacuum forming machine and a frame at the draw ratio of 1 : 1 to obtain a cup.
Appearance and peel strength of the cup thus obtained were evaluated. The results are shown in Table 1 hereinafter.
As seen from Table 1, the molded products of Examples 1 and 2 wherein NaOH was added in the amount of 0.05 equivalent to grafted maleic anhydride had good appearance and sufficient adhesion between the layers. The molded products of Examples 3 and 4 wherein NaOH was added l~ in the amount of 0.1 equivalent to grafted maleic anhydride has very good appearance and sufficient adhesion between the layers. By the way, even if the content of the adhesive resin composition in the blend was as low as 20 %, peeling strength was almost the same as that using the adhesive resin composition alone.
Comparative Examples 1 - 4 The same procedure as described in Examples 1 - 4 was repeated except that the amount of NaOH to be added was changed. The results of evaluation of appearance and peel ~5 strength are also shown in Table 1.

As seen from Table 1, the molded products of Comparative Examples 1 and 2 wherein no NaOH was added had :

..., , ,.,:, .. .
. :: . , .
, ::

; . :- . ~. ~; .. . . .
. : ., - -~ . -;, .. , , :: , ., uneven surfaces and less commercial value. When NaOH was added in an amount of 1.0 eguivalent, the modified copolymer colored in brown (Comparative Example 3). Further, it was impossible to intimately blend the modified copolymer and S the ethylene-ethyl acrylate copolymer, and not only extreme brownish graininess but also overall browning were observed (Comparative Example 4). Therefore, since these resins had less commercial value, coextrusion molding was not carried out.

:' Table l .
Ex. No. Amount of Content of Molded product NaOH toadhesion be addedresin (eq.)composition in blend (~) Appearance T-peel strength (kgtcm) Ex. 1 0.05 100 good 0.6 Ex~ 2 0.05 20 good 0.5 Ex. 3 0.1 100 very good 0.6 Ex. 4 ` 0.1 20 very good 0.5 Comp. 0 100 remarkable 0.1 -Ex. 1 unevenness 0.5 Comp. 0 20 remarkable 0.1 -Ex. 2 unevenness 0.5 Comp. 1.0 100 Molding was not carried Ex. 3 out because of remarkable coloring.
Comp. 1.0 20 Molding was not carried Ex. 4 out because of remarkable coloring.
*): Peel strength was determined toward the peripheral direction at the central body part of the cup (T-peel, 20 mm/min., 20C, 655RH).

:

~ ~ :

:

:

. - ~: : .

.

3L~76~372 Comparativ~ Example 5 Coextrusion mol~ing was carried out according to the same procedure as described in Example 1 except that only the e~hylene-ethyl acrylate copolymer was used as the resin of the layer (A) without addition of the adhesive modified polymer composition. Although the resulting molded product showed good appearance, adhesion between the layers were inferior and the layers were readily peeled off. Thus, the product had less commercial value.
Examples 5 - 6 An adhesive resin composition was obtained according to the same procedure as described in Example 1 except that an ethylene-ethyl acrylate copolymer having the ethyl acrylate component content of 30 %, MI (190C, 2,160 g) of 11.2 g/10 min., the density of 0.938 g/cm3 and the melting point of 80C was used and the amounts of maleic anhydride and cumene hydroperoxide were changed and that NaOH was addad in the amount Or 0.08 equivalent.
The resulting adhesive composition was dryblended ~0 with an ethylene-ethyl acrylate oopolymer having the ethyl acrylate component content of 30 %, MI (190C, 2,160 g) of 11~2 g/10 min., the density of 0.94 g/cm3 and the melting point of 80C in the weight ratio of 10 : 90 to obtain the resin for the layer (A). ~ ~ ~
~S By using EVOH obtained by saponification of~99.5 %
of the vinyl acetate segment of an ethylene-vinyl acetate copolymer having the Yiny~l acetate component content of 56 :

. ' :;~ . : , .,. ,`' ''':, . ~ . :.. ' ' ~27L~372 mole g which had C~] of 0.96 (in a mixed solution of phenol/water (85/15), 30C, dl/g) as the resin having gas barrier propertie~s (B), and by using a polycarbonate (manufactured and sold by Mitsubishi Chemical Industries Limited under the trade name of 'INOVAREX 7030A") as the hydrophobic thermoplastic resin (C), laminated materials were produced as followed.
A flat die type coextruding apparatus for three layers of three kinds of resins was employed. The apparatus had an extruder I having the inner diameter of 60 mm~ , an extruder II having the inner diameter of 40 mm~ and an extruder III having the inner diameter of 90 mm~ . The molten materials from the respective extruders were spread with respective manifolds in a die and then joined together in the die to form a multi-ply structure. The hydrophobic thermoplastic resin (C), the adhesive resin composition (A) and the resin having gas barrier properties (B) were fed into the extruders I, II and III, respectively and coextrusion was carried out at take-off speed of 4 m/min. to ~0 obtain a laminated sheet having three layers of C/A/B
t 200 ~50 ~/50 ~ ). Appearance and peel strength of the laminated sheet were evaluated. The results are shown in Table 2 hereinafter. ~ ~ ~
As seen from Table 2, the laminated sheets of Examples 5 and 6 had good appearance and sufficient adhesion between layers.

:

: .

:~7~72 Comparative Examples 6 - 9 The same procedure as described in Examples 5 and 6 was repeated except that the amount of NaOH was changed.
The results of evaluation o~ appearance and peel strength are also shown in Table 2.
As seen from Table 2, the products o~ Comparative Examples 6 and 7 wherein no NaOH was added had uneven surfaces and less commercial value. When NaOH was added in the amount of 1.0 equivalent, the modified copolymer colored in brown and had extremely inferior fluidity. Therefore, coextrusion molding was not carried out (Comparative Example 8). Further, it is impossible to intimately blend the modified copolymer wherein NaOH was added in the amount of 1.0 equivalent and the ethylene-ethyl acrylate copolymer, l~ and the sheet showed extreme brownish graininess and had less commercial value.

.

97~

Table 2 Ex. No. Amount of Content of Molded product NaOH to adhesion be added resin (eq.) composition in blend (%) Appearance T-peel strength (kg/cm) Ex~ 50.08 100 good 0.7 Ex. 60.08 20 good 0.9 Comp. 0 100 remarkable 0.2 -Ex. 6 unevenness 0.6 Comp. 0 20 remarkable 0.3 -Ex. 7 unevenness 0.6 Comp. 1.0 100 Molding was not carried Ex. 8 out because of remarkable~coloring.
Comp. l.O 20 remarkable 0.2 -Ex. 9 colored 0.4 graininess *): Peel strength was determined toward the axial direction at the central part of the sheet (T-peel, 20 mm/min., 20C, fi5~RH).

::: : : ~

, ,,' ~' ` ;. ` ' ~L~7~7'~

Example 7 An ethylene-ethyl acrylate copolymer t215 parts) having the ethyl acrylate component content Or 25 %, MI
(190C, 2,160 g) Or 6.3 g/10 min. and the melting point of 70C, and maleic anhydride (1.8 parts) were dissolved in puri~ied toluene (648 parts) and the solution was maintained at 180C. To the solution was continuously added a puri~ied toluene solution (180 parts) Or maleic anhydride (5 parts) with stirring over 2 hours. Concurrently~ a purified toluene solution (100 parts) of cumene hydroperoxide (1.2 part) was also continuously added over 2 hours. After completion of addition, the reaction was continued for an additional 30 min. After cooling, the reaction mixture was poured into a large amount Or methyl alcohol to precipitate a polymer. The polymer obtained was reprecipitated by using purified toluene as a solvent and methyl alcohol as a non-solvent. The resulting polymer contained 1.5 % Or maleic anhydride and had MI Or 4.3 g/10 min.
An aqueous solution containing a predetermined ~0 amount Or sodium hydroxide was homogeneously admixed with the polymer thus obtained. After partial drying, the mixture was molten, kneaded and~pellet~ized by using a vent extruder under reduced pressure with discharging volatiIes to obtain a modified copolymer. Thenj the modifled copolymer (20 parts) thus obtained was dryblended with ethylene-ethyl acrylate copolymer (80 parts) and~then molten, kneaded and pelletized to obtain a mixture of the '' ~ :

: ~ ' "' "~' ' i . ' i , " "

~Z7~7~:

copolymers.
Polyethylene terephthalate ( [n~ - 0.68)(75 parts), EVOH (ethylene component: 33 mole %; saponification degree:
99.9 %; MI (190C, 2,160 g): 1.5 g/10 min.)(15 parts) and 5 the mixture of the copolymers obtained above (10 parts) were dryblended. The mixture was fed to an extruder having a full flighted screw having the diameter of 40 mm, L/D of 24 and the compression ratio of 3.8, and a film was formed by using a flat die having 550 mm width. The operation conditions were as follows. Extrusion temperature: 200 -280C; Die temperature: 2650C; Thickness of the film rolled:
100 ~ ; and Continuous operation time: 8 hours. The film obtained showed good homogeneity and no phase separated foreign matter due to inferior mixing or inferior stability was observed.
A test piece of 90 mm square of the film obtained was oriented both lengthwise and laterally by using a biaxial orientation test apparatus (manufactured by Toyo Seiki Seisaku-sho K.K., Japan) at the draw ratio toward each ~0 direction of 3 and at the draw speed of 5 m/min. after heating at 850C for 1 min. Orientatlon was uniformly effected and, when the oriented film obtained was fixed on a wooden frame and subjec~ted to heat treatment in a hot air drier at 160~C, a film having hlgh strength and good gas ~5 barrier properties was obtained.
Comparative_Example~10 A modified copolymer~was~obtained according to the ..; ,' . `' , , :: .

. :........ :,, ,., :,: : . .
- ,. . , , ~ ,,. -: , , ., :: :

7~

same procedure as described in Example 7 except that NaOH
was not added. As in Example 7, the modified copolymer obtained was admixed with the ethylene-ethyl acrylate copolymer and, further, admixed with polyethylene terephthalate (PET) and EVOH. The resulting mixture was extruded to form a film. After 30 min. from initiation of the operation, a disuni~orm phase o~ separated foreign matter, which was not observed in the film of Example 7 began to appear in the film and increased with time.
~he film obtained had inferior appearance.
Examples 8 - 11 and Comparative Examples 11 - 14 A modified copolymer was obtained according to the same procedure as described in Example 7 except that the amount of NaOH was changed. A predetermined amount of the lS modified copolymer obtained was dryblended with a predetermined amount of ethylene-ethyl acrylate copolymer to obtain the ingredient (A) and, further, it was dryblended with PET and EVOY. as described in Example 7 in the amount as shown in Table 3 hereinafter. As in Example 7, the mixture was extruded to form a film. Surface appearance of the film obtained was evaluated. The results are shown in Table 3.
As seen from Table 3, the products of Examples 8 ~ ;
and 9 wherein 0.05 equivalent to grafted maleic anhydride of NaOH was added had good appearance. Further, the products of Examples lO and 11 wherein 0.1 equivalent of NaOH was added had very good appearance. On the other hand, the products of Comparative Examples 11 and 12 wherein no NaOH

J

" ,,. ~ , ... .

,, ' ~ " ' ' ' '~ '' ~ ' '., ' ' ' ~"

3~Z~317~

was added had unevenness on the surfaces and less commercial value. When O.9 equivalent of NaOH was added, the resulting modified copolymer colored in brown and had inferior fluidity. Therefore, film formation was not carried out S ~Comparative Example 13). The film obtained without using the modified copolymer had extremely inferior appearance ~Comparative Example 14).
When only ethylene-ethyl acrylate copolymer was used as the ingredient (A) without addition of any modified copolymer, and a film formation was carried out by extrusion according to the same procedure as described in Example 7, a ~isuniform phase of separated matter, which was not observed in the ~ilm of Example 7, began to appear just after initia-tion of the operation. The film obtained has an extremely inferior appearance.

. :: ,,',; , , , ,. :

.:, ;, ., ,. , . ,:
- ' :' , ' ' '','';, ' -:;;' ~ ": .. ..

Table 3 Ex, No. Formulation of resins Appearance (parts) of film Ingredients (A) (B) (C) Modified EEA PET EVOH
copolymer ~NaOH (eq)]
Ex. 8 2 [0.05] 8 7020 good Ex~ 9 5 [0.05] 5 7020 good Ex. 10 1 C0.1] 4 905 very good Ex. 11 2 [0.1] 0 908 very good Comp. ` 2 [O] 8 70 20 remarkable Ex. 11 unevenness Comp. 1 [O] 4 90 5 remarkable Ex. 12 unevenness Comp. - [0.9] - -- no film Ex. 13 formation due to extreme coloring Comp. O ~-] 10 70 20 remarkable Ex. 14 unevenness *) EEA: ethylene-ethyl acrylate copolymer having ethyl acrylate component content of 25 %, MI (190C, 2,160 g) Or 6.3 g~10 min~ and melting point of 70C
**) EVOH: having ethylene component of 33 mole %, 3aponification degree of 99.9 ~ and MI (190C, 2,160 g) of 1.5 g/10 min.

:

.' .. :

~Z~7~

Examples 12 - 15 and Comparative ExampIes 15 - 18 A modified copolymer having the maleic anhydride content of 2.9 % was obtained according to the same procedure as described in Example 7 except that an ethylene-vinyl acetate copolymer having the Yinyl acetate component content of 20 ~ and MI (190C, 2,160 g) of 2.1 g/10 min. was used, the amounts of maleic anhydride and cumene hydroperoxide were changed and potassium carbonate was used instead of NaOH. A predetermined amount of the modified copolymer obtained was dryblended with a predetermined amount of ethylène-vinyl acetate copolymer having the vinyl acetate content of 25 ~ and MI of 5.5 g~10 min. to obtain the ingredient (A).
EVOH having [n] of 0.96 (in a mixed solvent of phenol/water (85/15), 30C, dl/g) obtained by saponification o~ 99.5 % of the vinyl acetate segment of an ethylene-vinyl acetate copolymer having the vinyl acetate content of 56 mole ~ was used as the ingredient (B). A polycarbonate (manufactured and sold by Mltsubishi Chemical Industires Limlted, Japan under the trade name of NOVAREX 7030) was used as ingredient (C).
A flat die type coextrusion apparatus for three layers of three kinds of resins~w~as employ~d. The appsratus had an extruder I equi~pped with a ~ingle screw hsving the inner diameter Or 60 mm~ and L/D o~ 25, an extruder II
equipped with a single screw having the inner diametsr of 40 mm~ and L/D of 25 and a twln screw extruder I~

, . :

, . - ::- . ~;, ~ . :
.: .:: . . . : . . . .

~ 27~37~

equipped with screws intermeshing in the same direction and each having the inner diameter of 90 mm~ and L/D of 22.
Molten materials from the respective extruders were spread in respective manifolds in a die and laminated in the die.
A blend composition (M) of the above resins (A) (B) and (C) dryblended in a predetermined ratio, an ethylene-vinyl acetate adhesive resin (D) (manufactured by Mitsui Pstrochemical Industries, Ltd. in Japan under the trade name of `'Admer VF 600") and EVOH (B) were fed to the extruders III, II and I, respectiv ely and coextrusion was carried out to obtain a sheet having three layes, BtD/M
(50 ~/50 ~/450 ~) . Surface appearance of the sheet obtained was evaluated~ The results are shown in Table 4.
As seen from Table 4, the products of Examples 12 -15 wherein 0.14 equivalent of potassium carbonate to grafted maleic anhydride was added had good appearance. The products of Comparative Examples 15 and 16 wherein 0.01 equivalent of potassium carbonate was added had remarkable unevenness and les~ commercial value. When potassium ~a carbonate was àdded in the amount of 1.0 equivalent, the resulting modified resin was discolored to a brown color and had ~xtremely inferior fluidity. Therefore, coextruslon was not carried out (Comparative Example 17). The sheet of Comparative Example 18 wherein only ethylene-vinyl acetate copolymer was used as the ingredient (A) instead of the modified copolymer had remarkable graininess and less commercial value.
.

. :. ~ ... . .

, ;: ,.... . . .

~7~

Table 4 Ex. No. Formulation of resins Appearance (parts) of sheet Ingredients (A) (B) (C) Modified EVA PC EVOH
copolymer [K2C03 (eq)]
Ex. 12 2 [0.14~ 8 70 20 good Ex. 13 5 [0.14] 5 70 20 good Ex. 14 1 [0.14] 4 90 5 good Ex. 15 2 [0.14] 0 90 8 good Comp. 2 [0.005] 8 70 20 remarkable Ex. 15 unevenness Comp. 1 [0.005] 4 90 5 remarkable Ex. 16 unevenness Comp. - [1.0] - - - no film Ex. 17 formation due to extreme coloring Comp. O [-] 10 70 20 remarkable Ex. 18 unevenness *) EVA: ethylene-vinyl acetate copolymer having vinyl acetate component content of 20 %, MI (190C, 2,160 g) of 2.1 g/10 min.
~*) EVOH: having ethylene component of 44 mole ~, saponification degree of 99.5 % and MI (190C, 2,160 g) of 5.4 g/10 min.

' .. . ,". ~.,,.,., .. , ..... , ,.. : .

.,. . - ~: ~ ":. . , 7~7~:

Example 16 The cup obtained in Example 1 [(A) : (~) : (C) = 8 parts : 8 parts : 5 parts] was recovered and used in coextrusion as in Example 7 to obtain a film. The surface of the ~ilm obtained had good appearance.
Comparative Example 19 - 20 The same polymer as used in Examples 1 - 4 having the maleic acid component content o~ 1.5 % and MI of 4.3 g/10 min was admixed with 0.6 equivalent to maleic anhydride of magnesium oxide and the mixture was subjected to heating at 200C in an extruder having the inner diameter o~ 50 mm~ to pelletize.
Coextrusion and drawing were carried out according to the same procedure as described in Examples 1 - 4 except 15 that the pellets thus obtained were used to obtain a cup.
As seen from Table 5, the cup obtained had remarkable unevenness and less commercial value.
Table 5 Ex. No. Amount of Content of Product MgO teq.) modified *
copolymer (%) Appearance T-peel strength (kg/cm) Gomp. 0.6 100 remarkable 0.4 Ex. 19 unevenness Comp. 0.6 20 remarkable 0.4 Ex. 20 unevenness *- T-peel strength was determined axially at~the central part of the product. T~peel,~ 20 mm/min., 20C, 65 ~RH

:

Claims (19)

Claims:

1. An adhesive resin composition which comprises:
an ethylene-acrylate or methacrylate copolymer grafted with an ethylenic unsaturated carboxylic acid or its acid anhydride; and 0.02 to 0.6 equivalent relative to the ethylenic unsaturated carboxylic acid or its acid anhydride of a Periodic Table group Ia or IIa metal hydroxide; and optionally an ethylene-acrylate or methacrylate copolymer.

2. An adhesive resin composition according to claim 1, wherein the acrylate or methacrylate is ethyl acrylate or ethyl methacrylate.

3. An adhesive resin composition according to claim 1, wherein the ethylenic unsaturated carboxylic acid or its acid anhydride is maleic anhydride.

4. An adhesive resin composition according to claim 1, wherein the Periodic Table group Ia and IIa metal hydroxide is sodium hydroxide.

5. A laminated material which comprises a resin having gas barrier properties and a hydrophobic thermo-plastic resin laminated with an intervening adhesive resin composition comprising:
an ethylene-acrylate or methacrylate copolymer grafted with an ethylenic unsaturated carboxylic acid or its acid anhydride; and 0.02 to 0.6 equivalent to the ethylenic unsaturated carboxylic acid or its acid anhydride of a Periodic Table group Ia or IIa metal hydroxide; optionally and an ethylene-acrylate or methacrylate copolymer.

6. A laminated material according to claim 5, wherein the acrylate or methacrylate in the adhesive resin composition is ethyl acrylate or ethyl methacrylate.

7. A laminated material according to claim 5, wherein the ethylenic unsaturated carboxylic acid or its acid anhydride is maleic anhydride.

8. A laminated material according to claim 5, wherein the Periodic Table group Ia or IIa metal hydroxide is sodium hydroxide.

9. A laminated material according to claim 5, wherein the resin having gas barrier properties is a saponified ethylenen-vinyl acetate copolymer resin having an ethylene component content of 20 - 55 mole % and a saponification degree of not less than 90 %.

10. A laminated material according to claim 5, wherein the hydrophobic thermoplastic resin is a saturated polyester.

11. A laminated material according to claim 5, wherein the hydrophobic thermoplastic resin is a polycarbonate.

12. A laminated material according to claim 5, wherein the laminated material is a coextruded laminated material.

13. A resin composition which comprises:
(A) a mixture comprising:

an ethylene-acrylate, methacrylate or vinyl acetate copolymer grafted with an ethylenic unsaturated carboxylic acid or its acid anhydride, and 0,02 to 0.6 equivalent to the ethylenic unsaturated carboxylic acid or its acid anhydride of a Periodic Table group Ia or IIa metal compound; and optionally an ethylene-acrylate, methacrylate or vinyl acetate copolymer;
(B) a saponified ethylene-vinyl acetate copolymer resin having an ethylene component content of 20 - 55 mole %
and a saponification degree of not less than 90 %; and (C) a hydrophobic thermoplastic resin.

14. A resin composition according to claim 13, wherein the acrylate or methacrylate in the mixture is ethyl acrylate or ethyl methacrylate.

15. A resin composition according to claim 13, wherein the ethylenic unsaturated carboxylic acid or its acid anhydride is maleic anhydride.

16. A resin composition according to claim 13, wherein the Periodic Table group Ia or IIa metal compound is its hydroxide, salt or oxide.

17. A resin composition according to claim 13, wherein the metal compound is sodium hydroxide.

18. A resin composition according to claim 13, wherein the hydrophobic thermoplastic resin is a saturated polyester.

19. A resin composition according to claim 13, wherein the hydrophobic thermoplastic resin is a polycarbonate.