WO2005001187A1 - Flame-retardant non-woven fabric and method for production thereof - Google Patents

Abstract

A flame-retardant non-woven fabric which is produced by a method comprising subjecting a web containing a thermoplastic fiber and a heat-resistant fiber having an LOI value of 25 or more in a mass ratio of 88/12 to 55/45 to needle-punching or water jet punching.

Description

 Specification

 Flame-retardant nonwoven fabric and method for producing the same

 Technical field

 The present invention relates to a flame-retardant nonwoven fabric and a method for producing the same, and more particularly, to interior materials for automobiles, vehicles, aircraft, and ships, materials for civil engineering and construction, packing materials such as frozen containers, bedding products, The present invention relates to a flame-retardant nonwoven fabric that can be suitably used as a sound absorbing material and the like and a method for producing the same. Background art

 [0002] Conventionally, nonwoven fabrics have been widely used as civil engineering and construction materials, automotive materials, and living-related materials. In recent years, from the viewpoint of fire prevention, demands for flame-retardant nonwoven fabrics have been increasing, and as one of the major uses of this flame-retardant nonwoven fabric, automobile interior materials are known. Nonwoven fabrics used for automobile interior materials are required to have not only flame retardancy but also excellent recyclability when disposing of automobiles.

 [0003] Generally, when a nonwoven fabric is made flame-retardant, aramid fiber or polyclar fiber, which itself is a flame-retardant fiber, is used as a main component of the synthetic fiber constituting the nonwoven fabric. A mixture of spinning boric acid-based flame retardants is used, and a non-woven fabric is coated or impregnated with a binder coating liquid in which the flame retardants are dispersed.

 [0004] For example, Patent Documents 1 and 2 disclose a nonwoven mat obtained by subjecting a web in which 95% by weight of polyester fiber, polypropylene fiber or a mixture fiber thereof and 5% by weight of rayon fiber are subjected to needle punching treatment to a nonwoven fabric mat. An automotive interior obtained by adhering HYBREM MARGILLON and performing a drying treatment to form a flame-retardant resin film and then integrally laminating the surface having the resin film and a glass fiber mat. The materials are listed. However, it is difficult to recycle the interior material because the glass fiber mat is integrated, and there is a problem that dioxin may be generated when the interior material is incinerated.

[0005] Patent Document 3 discloses a flame-retardant short fiber nonwoven web layer made of a polyester copolymer obtained by copolymerizing a polyester polymer and a phosphoric acid compound on both sides of a polyester fiber nonwoven web layer. A flame-retardant nonwoven fabric is described in which the constituent fibers of both web layers are laminated and entangled with each other. However, this flame-retardant nonwoven fabric is made Is melted, causing dripping of the liquid melt, and the drip resin spreads, causing problems with the anti-fusing properties.

 [0006] As a method for improving the fusibility of a nonwoven fabric, Patent Document 4 discloses that a web in which polyester fiber and flame-retardant rayon fiber or modacrylic fiber are blended is needle-punched and then further stitch-bonded. Thus, a method for imparting flame retardancy and fusibility is described. However, since flame-retardant rayon fiber or modalyl fiber treated with a flame retardant is used for the nonwoven fabric constituent fiber, toxic gas may be generated during combustion, which poses a problem in terms of environmental protection.

 [0007] On the other hand, Patent Document 5 discloses a mixed spinning of 110 to 30% by weight of a yarn yarn aramide fiber and 99 to 70% by weight of one or two kinds of fibers selected from nylon fibers and polyester fibers. A flame-retardant pile fabric comprising a mixed yarn of 50 to 90% by weight of a polyester fiber and 50 to 10% by weight of a non-molten fiber is disclosed. However, since a backing layer made of an acrylate resin latex is formed on the back surface, there is a problem that recyclability is poor and economic efficiency is poor.

 Patent Document 1: JP-A-62-43336

 Patent Document 2: JP-A-62-43337

 Patent Document 3: JP-A-9-59857

 Patent Document 4: JP-A-2002-348766

 Patent Document 5: Japanese Patent Application Laid-Open No. 9-250052

 Disclosure of the invention

 Problems to be solved by the invention

[0008] The present invention has been made in view of the above-mentioned conventional problems, and it is possible to obtain good flame retardancy by incorporating a flame retardant, and to obtain a liquid melt at the time of melting constituent fibers. It is an object of the present invention to provide a flame-retardant nonwoven fabric which has low shrinkage by dripping, is excellent in economy and recyclability, and a method for producing the same.

 Means for solving the problem

The present inventors have conducted intensive studies to achieve the above object, and as a result, a web containing thermoplastic fibers and heat-resistant fibers having an LOI value of ¾5 or more in a mass ratio of 88 / 12-55Z45. In addition, it has been found that a flame-retardant nonwoven fabric in which a flame is quickly eliminated can be obtained by performing, for example, needle punching treatment and entanglement without relying on adhesion or heat fusion, and further studies have been carried out. Was completed.

[0010] That is, the flame-retardant nonwoven fabric of the present invention is characterized in that a web containing thermoplastic fibers and heat-resistant fibers having an LOI value of 25 or more in a mass ratio of 88 / 12-55Z45 is added to the web by needle punch or water. It is characterized by jet punching. The web preferably contains thermoplastic fibers and heat-resistant fibers having an LOI value of 25 or more in a mass ratio of 85Z15 65Z35. The heat-resistant fibers include aramide fiber, polyphenylene sulfide fiber, polybenzoxazole fiber, polybenzthiazole fiber, polybenzimidazole fiber, polyetheretherketone fiber, polyarylate fiber, polyimide fiber, fluorine fiber, and flame-resistant fiber. One or two or more organic fibers selected from fibers are preferable.

[0011] The flame-retardant nonwoven fabric preferably has a bulk density in the range of 0. 01-0. LgZcm ^3.

 In the flame-retardant nonwoven fabric of the present invention, it is more preferable that the thermoplastic fiber is one or more fibers selected from polyester fibers, polypropylene fibers and nylon fibers.

 The flame-retardant non-woven fabric is preferably a non-woven fabric comprising a polyester fiber which is a thermoplastic fiber and a para-aramid fiber which is a heat-resistant fiber having an LOI value of 25 or more.

[0012] Further, in the method for producing a flame-retardant nonwoven fabric of the present invention, the thermoplastic fiber and the heat-resistant fiber having an LOI value of 25 or more have a mass ratio of 88 / 12-55 / 45, preferably 85. Needle punching or water jet punching is performed on the web containing the ratio of / 15 to 65/35.

 The invention's effect

[0013] As described above, according to the present invention, it is possible to obtain a good flame retardancy without containing a flame retardant S, and there is no drip of the liquid melt when the constituent fibers are melted. A flame-retardant nonwoven fabric having low shrinkage, good workability and abrasion resistance, and excellent in heat insulation and sound absorption can be obtained at low cost. Further, the flame-retardant nonwoven fabric of the present invention does not require the use of a binder, and thus has excellent recyclability. BEST MODE FOR CARRYING OUT THE INVENTION

[0014] The flame-retardant nonwoven fabric of the present invention comprises a thermoplastic fiber and a heat-resistant fiber having an LOI value of 25 or more: thermoplastic fiber / heat-resistant fiber = 88 / 12-55 / 45 (preferably 85 / 15- 65/35) The web containing (mass ratio) is needle-punched or water-jet punched.

 [0015] The thermoplastic fibers used in the present invention are not particularly limited as long as the fibers are made of a thermoplastic resin. Examples of the thermoplastic resin include a polyester resin, a polyamide resin, an acrylic resin, a polypropylene resin, and a polyethylene resin. The thermoplastic fiber can be produced from a thermoplastic resin by a known method such as wet spinning, dry spinning or melt spinning. Thermoplastic fibers include one or more fibers selected from polyester fibers, polyamide (eg, nylon) fibers, acrylic fibers, polypropylene fibers, polyethylene fibers, and the like. Thus, polyester fibers, polypropylene fibers, and nylon fibers are preferred. In the present invention, the above-mentioned fibers can be used alone or as a mixture in an arbitrary ratio as thermoplastic fibers. In particular, polyester fibers are preferred because the raw material polyester can be easily recycled by heat melting of the used nonwoven fabric, the economic efficiency is excellent, the feel of the nonwoven fabric is excellent, and the moldability is excellent.

[0016] The polyester fiber is not particularly limited as long as it is a fiber made of a polyester resin. The polyester resin is not particularly limited as long as it is a polymer resin containing an ester bond in the repeating unit, and may be a polyester resin comprising a dicarboxylic acid component having ethylene terephthalate as a main repeating unit and a glycol component. Examples of the dicarboxylic acid component include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, and 1,4-cyclohexanedicarboxylic acid. Examples of the glycol component include ethylene glycol propylene, propylene glycol, tetramethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Part of the dicarboxylic acid component may be replaced with adipic acid, sebacic acid, dimer acid, sulfonic acid metal-substituted isophthalic acid, etc. , 1,4-cyclohexanediol, 1,4-cyclohexane It may be replaced with sandimethanol, polyalkylene glycol, or the like.

 [0017] The polyester fiber is usually produced by a known spinning method such as polyester resin melt spinning. Examples of the polyester fiber include polyethylene terephthalate (PET) fiber, polybutylene terephthalate (PBT) fiber, polyethylene phthalate (PEN) fiber, polycyclohexylene dimethylene terephthalate (PCT) fiber, and polytrimethylene terephthalate (PTT) fiber. ) Fiber, polytrimethylene naphthalate (PTN) fiber, biodegradable polyester fiber, low-melting polyester fiber and the like. Particularly preferred is polyethylene terephthalate (PET) fiber. The polyester fibers include various inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, and dinoreconidic acid, as well as particles such as crosslinked polymer particles and various metal particles. Conventional antioxidants, sequestering agents, ion exchange agents, anti-coloring agents, waxes, silicone oils, various surfactants, etc. are added.

 The polypropylene fiber is not particularly limited as long as it is a fiber made of a polypropylene resin. Polypropylene resin contains a —CH (CH) CH— structure in the repeating unit

 3 2

 It is not particularly limited as long as it is a polymer resin, and examples thereof include a propylene one-year-old olefin copolymer resin such as a polypropylene resin and a propylene-ethylene copolymer resin. Polypropylene fibers are produced from the above polypropylene resin by a known spinning method such as melt spinning. The polypropylene fiber may be added to the polyester fiber described above, or may be added with various additives.

[0019] The nylon fibers include polypromamide (nylon 6), polyhexamethylene adipamide (nylon 66), polytetramethylene adipamide (nylon 46), polyhexamethylene sebacamide (nylon 610), Hexamethylene dodecamide (nylon 612), polydecaneamide (nylon 11), polydodecaneamide (nylon 12), polymethaxylene adipamide (nylon MXD6), polyhexamethylene terephthalamide (nylon 6T), Polyhexamethylene isophthalamide (nylon 61), polyxylylene adipamide (nylon XD6), polycapramide / polyhexamethylene terephthalamide copolymer (nylon 6 / 6T), polyhexamethylene adipamide / polyhexa Methylene terephthalamide copolymer (nylon 66 / 6T), polyhexene methylene Pamido / poly hexamethylene isophthalamide copolymer (nylon 66/61) , Polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaprolamide copolymer (nylon 66/61/6), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), Polyhexamethylene terephthalamide Z polydodecaneamide copolymer (nylon 6T / 12), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I) or Polyhexamethylene terephthalamide Z Nylon fibers made of nylon resin such as nylon copolymer resin such as poly_2-methylpentamethylene terephthalamide copolymer (nylon 6TZM5T). The method for producing nylon fibers from the nylon resin may be a known method such as melt spinning. In addition, various additives which may be added to the above-mentioned polyester fiber may be added to the nylon fiber.

 [0020] The cross-sectional shape of the thermoplastic fiber is not particularly limited, and may be a true circular cross-section or an irregular cross-section. For example, oval, X-section, Y-section, T-section, L-section, star-shaped section, leaf-shaped section (for example, three-lobe, four-lobe, five-lobe, etc.), and other polygonal sections (for example, triangle , Square, pentagon, hexagon, etc.). Further, the thermoplastic fiber may be a hollow fiber or a crimped fiber.

 The fiber length and fineness of the thermoplastic fiber are not particularly limited, and can be appropriately determined according to the compatibility with the heat-resistant fiber and the use of the flame-retardant nonwoven fabric. The thermoplastic fiber may be either a long fiber or a short fiber. In the case of a short fiber, the fiber length is preferably 10 to 100 mm, more preferably 20 to 80 mm. The fineness of the thermoplastic fiber is preferably 0.5-30 dtex, more preferably 1.0-10 dtex.

 [0021] The thermoplastic short fibers can be used alone or in combination of two or more. It is also possible to mix and use thermoplastic short fibers of the same type or different types with different fineness and fiber length. In this case, the mixing ratio of the fibers is arbitrary and can be appropriately determined according to the use and purpose of the nonwoven fabric.

[0022] The heat-resistant fiber used in the present invention has an LOI value (critical oxygen index) of 25 or more, and is flame-retardant by adding a flame retardant such as flame-retardant rayon fiber, flame-retardant vinylon fiber, and modacrylic fiber. Excluded fibers are not included. Here, the LOI value is required to burn more than 5cm continuously. Meaning the lowest oxygen concentration, the LOI value is a value measured by the JIS L 1091 method. If the LOI value of the heat-resistant fiber is 25 or more, flame retardancy can be imparted to the non-woven fabric.

[0023] Examples of the heat-resistant fiber include aramide fiber, polyphenylene sulfide fiber, polybenzoxazole fiber, polybenzthiazole fiber, polybenzimidazole fiber, polyetheretherketone fiber, polyarylate fiber, and polyimide fiber. And one or more organic fibers selected from fluorinated fibers and oxidized fibers. As these fibers, all conventionally known fibers and those produced according to a known method or a method analogous thereto can be used. Here, the oxidized fiber is mainly produced by firing acrylic fiber at 200 to 500 ° C in an active atmosphere such as air, and is a precursor of carbon fiber. For example, the product name "Rastan" (registered trademark) manufactured by Asahi Kasei Corporation, and the product name "Pyromettas" (registered trademark) manufactured by Toho Tenax Co., Ltd. can be exemplified. The heat-resistant fiber other than the flame-resistant fiber is produced from the corresponding resin using known means such as spinning (wet, dry, melting, etc.).

[0024] Among the above heat-resistant fibers, from the viewpoint of low shrinkage and processability, aramide fibers, polyphenylene sulfide fibers, polybenzoxazole fibers, polyetheretherketone fibers, polyarylate fibers, and flame-resistant fibers In particular, aramide fibers are preferred, in which at least one organic fiber selected from the group consisting of:

 Among the aramide fibers, para-based aramide fibers and meta-based aramide fibers are particularly preferably para-aramid fibers in view of the fact that a certain amount of heat shrinkage is small. Examples of the para-aramid fiber include polyparaphenylene terephthalamide fiber (manufactured by Dupont Co., Ltd., Toray's Dupont Co., Ltd., trade name “KEVLAR” (registered trademark)), and copolybaraf-dylene-1,3,4'-oxydif. Commercially available products such as nitrene terephthalamide fiber (manufactured by Teijin Limited, trade name “Technola” (registered trademark)) can be used.

 [0025] The heat-resistant fiber used in the present invention is excellent in that it is a low-shrinkable fiber that does not melt-shrink when the nonwoven fabric burns. In the present invention, the heat-resistant fiber is preferably a fiber having a dry heat shrinkage at 280 ° C of 1% or less.

[0026] The fiber length and fineness of the heat-resistant fiber are not particularly limited, and may be different from those of the thermoplastic fiber. Can be appropriately determined depending on the compatibility of the resin and the use of the flame-retardant nonwoven fabric. Usually, a fineness of 0.5 to 30 dtex, particularly 1.0 to 10 dtex is preferably used. Although the mechanism of flame retardancy in the nonwoven fabric of the present invention is not clear, it is considered that the heat-resistant fiber entangled with the thermoplastic fiber has a role of blocking the combustion of the thermoplastic fiber. The heat-resistant fiber may be a long fiber or a short fiber. The fiber length of the heat-resistant short fiber is not particularly limited, but in consideration of flame retardancy and productivity, it is preferable that the fiber length be 20 100 mm, particularly 40-80 mm.

[0027] The heat-resistant fibers can be used alone or in combination of two or more. Fibers of the same kind or different kinds and having different fineness and fiber length can be mixed and used. In this case, the mixing ratio of the fibers is arbitrary, and can be determined appropriately according to the use and purpose of the nonwoven fabric.

 [0028] The thermoplastic fiber and the heat-resistant fiber used in the present invention are blended in a ratio of thermoplastic fiber Z heat-resistant fiber = 88 / 12-55 / 45 (mass ratio). If the ratio exceeds 88/12, the flame retardancy of the nonwoven fabric becomes insufficient, and liquid dripping (drip) tends to occur. In other words, by including the heat-resistant fiber in the web at 12% by mass or more and entangled with the thermoplastic fiber, combustion and melting of the thermoplastic fiber can be prevented. On the other hand, when the above ratio is less than 55/45, the flame retardancy is good, but the workability when processing the nonwoven into a desired size becomes poor, and the economic efficiency is also poor. From the viewpoint of flame retardancy and processability, the ratio (mass ratio) of thermoplastic fiber / heat-resistant fiber is more preferably 85 / 15-55 / 45, and most preferably 85 / 15-65 / 35. It is.

 [0029] In the present invention, in order to improve the wear resistance of the nonwoven fabric, fine denier thermoplastic fibers can be contained in the thermoplastic fibers. Examples of the fine denier thermoplastic fiber include one or more fibers selected from the above-mentioned polyester fiber, polypropylene fiber, polyethylene fiber, linear low-density polyethylene fiber, ethylene monoacetate copolymer fiber, and the like. Can be mentioned.

[0030] The fineness of the fine denier thermoplastic fiber is usually a force S using a 0.0001 5. Odtex, preferably 0.5 to 6.6 dtex, particularly 1.1 to 3.3 dtex. But preferred. The fine denier thermoplastic fiber may be either a long fiber or a short fiber. When the fine denier thermoplastic fiber is a short fiber, the fiber length is not particularly limited and can be appropriately determined depending on the compatibility with the heat-resistant fiber and the use of the flame-retardant nonwoven fabric. More preferably, it is 20-80 mm.

 [0031] When fine denier thermoplastic fibers are blended in the web, the blending ratio of the fine denier thermoplastic fibers is 30 to 70% by mass, more preferably 30 to 70% by mass, based on the total amount of the thermoplastic fibers in the web. Desirably, it is 50% by mass.

[0032] In the present invention, the basis weight of the web containing the above-mentioned thermoplastic fiber (containing fine denier fiber as necessary) and heat-resistant fiber depends on the use of the flame-retardant nonwoven fabric and the like. It can be appropriately determined according to the conditions, but from the viewpoints of the shape retention of the web layer, the energy required for entanglement, and the like, it is usually about 150 to 800 gZm ² .

 [0033] The web can be produced by a conventional web forming method using a conventional web forming apparatus. For example, a web is formed after the mixed thermoplastic fiber and the heat-resistant fiber are spread using a force machine.

 [0034] The nonwoven fabric of the present invention is provided with a needle punch or a water jet punch on a web containing thermoplastic fibers and heat-resistant fibers having an LOI value of 25 or more at a mass ratio of 88 / 12-55 / 45. It is obtained by applying. By performing the punching treatment, the fibers of the web can be entangled to improve the wear resistance of the nonwoven fabric.

[0035] The needle punching treatment may be either one-sided or two-sided treatment of the web. If the punch density is too low, the abrasion resistance of the nonwoven fabric will be insufficient, and if it is too high, the bulk density will decrease, and the heat insulating effect and the sound absorption effect will be impaired due to the decrease in the air volume ratio in the nonwoven fabric. —300 times / cm ² , more preferably 50-100 times / cm ² .

 In the present invention, needle punching can be performed according to a conventional needle punching method using a conventional needle punching device. After the needle punching, the flame-retardant nonwoven fabric of the present invention can be obtained by drying as in the related art.

A water jet punch is a device in which a large number of injection holes having a hole diameter of, for example, 0.05 to 0.2 mm are arranged in a line or a plurality of lines at a hole interval of 0.3 to 10 mm. It can be carried out according to a conventional water jet punching method using a water jet punching device that jets a high-pressure water stream at 250 kg / cm ² G. Injection hole and ゥ The distance from Eb should be about 110cm. After the water jet punch, the flame-retardant nonwoven fabric of the present invention can be obtained by drying as before.

[0038] The flame-retardant nonwoven fabric of the present invention has a bulk density in the range of 0.01 to 0.2 gZcm ³ from the viewpoints of flame retardancy, heat insulation, sound absorption, abrasion resistance, workability, and the like. it is preferred instrument 0. 01 -0. lg / it cm in the range of ³ more preferably tool more preferably ^{0. 01 -0. 08g / cm 3} , most preferably 0. 02-0. 05g / Les, Shi desirable in the range of cm ^3. As described above, by controlling the bulk density of the nonwoven fabric, the proportion of air (oxygen) in the nonwoven fabric is controlled within a certain range, and the nonwoven fabric is provided with excellent flame retardancy, heat insulation, and sound absorption. You.

 [0039] In the present invention, the thickness of the nonwoven fabric is not particularly limited, and can be appropriately determined depending on the purpose and application.

 [0040] The flame-retardant nonwoven fabric of the present invention may be colored with a dye or a pigment as necessary. As a coloring method, a dyed or pigment mixed with a polymer before spinning may be used and spun original yarn may be used, or fibers colored by various methods may be used. The flame-retardant nonwoven fabric may be colored with a dye or a pigment.

 [0041] The flame-retardant nonwoven fabric of the present invention does not chemically bond the webs in the fibers. Therefore, the used nonwoven fabric is collected, washed and the like as necessary, and then the entangled fibers are unraveled. Can be easily recycled.

 [0042] The flame-retardant nonwoven fabric of the present invention may have an acrylic resin emulsion, a phosphate ester-based flame retardant, a halogen-based flame retardant, if necessary, in order to further improve its flame retardancy and abrasion resistance. An acrylic resin emulsion or an acrylic resin solution containing a known flame retardant such as a flame retardant or a hydrated metal compound may be coated or impregnated.

[0043] The flame-retardant nonwoven fabric of the present invention can be used for various applications by processing it to an appropriate size, shape, etc. by applying a known method or the like according to its purpose or application. The flame-retardant nonwoven fabric of the present invention can be used for all applications where flame retardancy is required.For example, automobiles, vehicles such as freight cars, aircrafts, interior materials for transportation equipment such as ships, civil engineering and construction It can be suitably used for civil engineering 'building materials such as wall members, floor members, ceiling members, etc .; packing materials for frozen containers, etc .; bedding products, sound absorbing members, and the like. In particular, when used as an interior material in the engine room of a car, the flame spreads to the driver's seat when the engine ignites. In addition, it is possible to prevent noise generated from the engine room from leaking to the outside. In addition, car ceiling materials, rear packages, door trims; insulators for dashboards of cars, trains, aircraft, etc .; various heat insulating materials, heat shielding materials, heat insulating materials; protective clothing for firefighting and high-temperature work, protective gloves, It can be used for various applications such as protective hats; welding protection sheet at the site; grass-proof material; speaker diaphragm; battery separator; Example

 Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to only the following Examples.

(Example 1)

Polyester fiber staple (1.7dtex X 51mm) and "Kevlar" (registered trademark) staple, a para-aramid fiber manufactured by Toray DuPont (1.7dtex X 51mm, dry heat shrinkage at 280 ° C) 0.1% or less and a LOI value of 29) were mixed in a conventional manner so as to have a mass ratio of 70/30, to produce a web having a basis weight of 400 g / m ² .

The web was punched in a conventional manner under the conditions of a needle density of 70 needles / cm ² and a needle depth of 12. Omm, and then dried in a conventional manner to obtain a flame-retardant nonwoven fabric. The bulk density of the obtained nonwoven fabric was 0.04 g / cm ³ .

(Comparative Example 1)

 A nonwoven fabric was obtained by repeating the same operation as in Example 1 except that a web was prepared only from polyester fibers (1.7 dtex X 51 mm).

(Comparative Example 2)

 "Kepler" (registered trademark) staple, a para-aramid fiber manufactured by Toray DuPont (1.7 dtex X 51 mm, dry heat shrinkage at 280 ° C 0.1% or less, L〇I value 29 ) Alone, except that a web was produced, to obtain a nonwoven fabric by repeating the same operation as in Example 1.

 [0048] Each physical property value in the above Examples and Comparative Examples was measured as follows.

[Dry heat shrinkage at 280 ° C] The length of the fiber after standing in air at 280 ° C. for 30 minutes was measured, and the ratio of the contracted length of the fiber after standing to the length of the fiber before standing was determined.

(Evaluation)

 The nonwoven fabrics obtained in the above Examples and Comparative Examples were evaluated for flame retardancy and shrinkage by the following methods. The results are shown in Table 1.

 〔Flame retardance〕

 The test was performed based on JIS A 1322 "Testing method for flame retardancy of thin building materials". In other words, using a non-woven fabric specimen cut to a size of 20 cm X 30 cm, visually observe the burning situation when approaching a flame, the presence or absence of drip, and the presence or absence of perforations in the non-woven fabric. Evaluation was based on criteria.

 (1) Drip properties 〇: No drip, X: Drip

 (2) Perforability 〇: Hole does not open, X: Hole opens

 (Shrinkage)

 One end of a test piece (width 3 cm, length 10 cm) cut from the nonwoven fabric was lit, and the state of the nonwoven fabric after the flame was extinguished was determined according to the following criteria.

〇: Burnt marks remain, but hardly shrink.

X: Shape is lost

[Workability]

 Ease of processing when processing the nonwoven fabric into a desired shape and size was determined according to the following criteria.

〇: Easy to cut

△: slightly difficult to cut

X: difficult to cut

[table 1] Non-woven fabric evaluation

No. weight

 Fiber composition (wt%) Drill Noah perforation Low shrinkage Workability

(g / m ² )

 Wood's I-stell fiber 70

 Example 1 400 0.04 〇 〇 〇 〇

 Λ 'La system 7 Ramito' fiber 30

 Comparative Example 1 Wood's Iris Fiber 100 400 0.04 X X X 〇 Comparative Example 2 Λ 'Laramid Fiber 100 400 0.04 〇 〇 〇 Δ

[0050] From the results in Table 1, the nonwoven fabric obtained in the example has the property of burning once when approaching a flame, but has the property of quickly stopping combustion and extinguishing the fire, and the nonwoven fabric obtained in Comparative Example 2 Excellent in cutting workability compared to. Furthermore, it has a soft feel and good flexibility. In contrast, the ratio

 it

 In the nonwoven fabric obtained in Comparative Example 1, as soon as the flame approaches, the flame penetrates the nonwoven fabric to make a hole in the nonwoven fabric, and the molten resin drip. Furthermore, if one end was ignited, the entire nonwoven fabric would burn.

 Industrial applicability

 [0051] The flame-retardant nonwoven fabric of the present invention is suitably used for interior materials of automobiles, vehicles, aircraft, ships, civil engineering and construction materials, packing materials such as frozen containers, bedding products, sound absorbing materials, and the like.

Claims

The scope of the claims

 [1] A web containing thermoplastic fibers and heat-resistant fibers having an LOI value of 25 or more at a mass ratio of 88Z12-55 / 45, which is characterized by being subjected to needle punching or water jet punching. Flame retardant nonwoven.

 [2] The flame-retardant nonwoven fabric according to claim 1, wherein the web contains a thermoplastic fiber and a heat-resistant fiber having an LOI value of 25 or more in a mass ratio of 85Z15-65 / 35.

 [3] The heat-resistant fiber is aramide fiber, polyphenylene sulfide fiber, polybenzoxazole fiber, polybenzothiazole fiber, polybenzimidazole fiber, polyetheretherketone fiber, polyarylate fiber, polyimide fiber, fluorine 3. The flame-retardant nonwoven fabric according to claim 1, which is one or more kinds of organic fibers selected from fibers and flame-resistant fibers.

[4] The flame-retardant nonwoven fabric according to any one of claims 1 to ³ , wherein the nonwoven fabric has a bulk density in the range of 0.01 to 0.1 lg / cm ³ .

[5] The flame-retardant nonwoven fabric according to any one of claims 1 to 4, wherein the thermoplastic fiber is one or more fibers selected from polyester fiber, polypropylene fiber and nylon fiber. .

 [6] The flame-retardant nonwoven fabric according to claim 1, 2 or 4, wherein the thermoplastic fiber is a polyester fiber and the heat-resistant fiber is a para-aramid fiber.

[7] A thermoplastic fiber and a heat-resistant fiber having an LOI value of 25 or more are mass ratio of 88 / 12—55 / 4

A method for producing a flame-retardant nonwoven fabric, characterized by subjecting a web containing at a ratio of 5 to needle punching or water jet punching.

[8] Thermoplastic fiber and heat resistant fiber with LOI value of 25 or more are mixed by mass ratio of 85 / 15—65 / 3

A method for producing a flame-retardant nonwoven fabric, characterized by subjecting a web containing at a ratio of 5 to needle punching or water jet punching.