JP2006317805A - Sound insulating fiber and soundproof material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soundproof material which is high in sound insulating performance and light in weight, and to provide a sound insulating fiber useful for the soundproof material. <P>SOLUTION: The sound insulating fiber is constituted of thermoplastic resin and single-fiber fineness is adjusted to 5 dtexes or smaller and cross-sectional flattening is adjusted to 7 to 40. The thermoplastic resin may be polyvinyl alcohol resin, and for example, the fiber may be vinylon fiber or polyclar fiber. The fiber may contain stratified inorganic compound of a mass proportion of about 0.01 to 30% in the fiber and the face direction of the stratified inorganic compound may be oriented to the direction of the flat face of the fiber. The soundproof material may be prepared of nonwoven fabric which contain mass proportion of 50% or higher of the fiber. In the soundproof material, average apparent density may be 0.01 to 0.5 g/cm<SP>3</SP>, and the mesh density may be about 30 to 500 g/m<SP>2</SP>and permeability may be about 1 to 150 ml/cm<SP>2</SP>/second. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fiber excellent in soundproofing properties such as sound absorbing and insulating properties and a soundproofing material using the fiber (for example, a soundproofing material used in vehicles and buildings).

  Conventionally, in order to reduce noise in the passenger compartment and living space, soundproofing materials have been used as interior materials for vehicles such as automobiles and buildings such as roads, houses and factories. As such a soundproofing material, sheet-like fibers such as natural fibers and synthetic fibers are widely used because they are excellent in sound absorption and insulation properties, lightweight properties, breathability, and the like.

For example, in Japanese Patent Laid-Open No. 9-226480 (Patent Document 1), a main fiber, a binder fiber, and a fine fiber made of a thermoplastic resin are oriented substantially perpendicular to the sheet surface, and the fibers are Is a pad formed of a sheet-like fiber structure heat-sealed, wherein the fiber structure has a density of 0.01 to 0.05 g / cm ³ and a dynamic spring constant of 0.1 × 10 ^{5 to} 0.00. An automotive silencer pad that is 5 × 10 ⁵ N / m is disclosed. However, this silencer pad has a complicated structure, and not only productivity is lowered but also soundproofing is not sufficient.

Japanese Patent Application Laid-Open No. 5-181486 (Patent Document 2) uses synthetic fiber staples having a single fiber fineness of 5 denier or less as a raw material, and uses this material at least 50% by weight or more and an average apparent density of 0.02 to 0. A sound absorbing material composed of a fiber assembly molded to 2 g / cm ³ , and at least a modified cross-section fiber having a cross-sectional shape with a long outer periphery of the fiber compared to a circular outer periphery equivalent to the cross-sectional area of the fiber, A sound absorbing material containing 30% by weight or more is disclosed. This document describes a thermoplastic resin such as polyester, polyamide, polypropylene, or polyethylene as a material for the irregular cross-section fiber. Also, as the irregular cross section, a flat polygon, a convex polygon having a cross section with a sharp corner such as a triangle, a concave polygon cross section such as a Y shape, a cross shape, and a starfish shape, one fiber is divided. Apparently, there are many fibers made of ultrafine fibers. In the examples, 2 denier flat cross-section polyester fibers are used. However, in this sound absorbing material, the flatness of the fiber is small and the soundproofing property is not sufficient.

Furthermore, Japanese Patent Laid-Open No. 2000-202933 (Patent Document 3) discloses a sound insulating material composed of a porous sound absorbing material and a skin material, wherein the sound absorbing material has two or more layers having different material compositions. The sound insulation material comprised by this is disclosed. This document describes, as the first layer of the sound absorbing material, a sound absorbing material mainly composed of synthetic fibers having an average fiber diameter of 5 denier or less and an average apparent density of 0.01 to 0.5 g / cm ³ . This document describes that the synthetic fiber is most preferably a polyester fiber. In the examples, 2-denier flat cross-section polyester fibers are used as the first sound-absorbing material. However, this sound-absorbing material has a complicated structure, and not only the productivity is lowered but also the soundproofing property is not sufficient.
JP-A-9-226480 (Claim 1) JP-A-5-181486 (Claim 1, paragraph numbers [0006] [0015], Examples) JP 2000-202933 A (Claims 1 and 2)

  Accordingly, an object of the present invention is to provide a soundproofing material having high soundproofing properties and light weight, and a soundproofing fiber useful for the soundproofing material.

  Another object of the present invention is to provide a method capable of easily producing a soundproof material having high soundproofness and lightness.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that when a thermoplastic resin fiber having a small fineness and a high flatness is used, a soundproofing material having high soundproofing properties and light weight can be obtained. The present invention has been completed.

  That is, the soundproof fiber of the present invention is a fiber composed of a thermoplastic resin, has a single fiber fineness of 5 dtex or less, and a cross-sectional flatness of 7 to 40. The thermoplastic resin may be a polyvinyl alcohol resin. For example, the fiber may be a vinylon fiber or a polyclar fiber. The fiber may further contain a layered inorganic compound in a proportion of about 0.01 to 30% by mass in the fiber, and the plane direction of the layered inorganic compound may be oriented in the flat plane direction of the fiber.

The present invention also includes a soundproof material composed of a fiber assembly including the soundproof fiber. This soundproof material may be composed of a nonwoven fabric containing 50 mass% or more of soundproofing fibers. The soundproofing material may further contain a binder such as a thermoplastic resin or a thermosetting resin, in particular, a fibrous binder having heat-fusibility. This soundproof material has an average apparent density of about 0.01 to 0.5 g / cm ³ , a basis weight of about ³⁰ to 500 g / m ² , and an air permeability of about 1 to 150 ml / cm ² / sec. May be.

  The present invention also includes a method for producing the soundproof fiber by spinning a thermoplastic resin. In this method, a dope containing a polyvinyl alcohol resin and a layered inorganic compound may be wet-spun. The present invention also includes a method for producing the soundproofing material using the soundproofing fiber. Furthermore, the present invention includes a soundproofing method using the soundproofing material.

  In the specification of the present application, “sound insulation” is used as a meaning including both sound absorbing and insulating properties, that is, both the sound absorbing properties and the sound insulating properties.

  In the present invention, since a thermoplastic resin fiber having a single fiber fineness of 5 dtex or less and a cross-sectional flatness of 7 to 40 is used, a soundproof material having high soundproofness and lightness can be easily produced. Therefore, the soundproofing material of the present invention is suitable, for example, for interior materials for vehicles such as automobiles and buildings such as roads, houses, factories, and the like.

[Soundproof fiber]
The soundproof fiber of the present invention is composed of a thermoplastic resin. The thermoplastic resin may be any conventional thermoplastic resin used for fibers. For example, polyolefin resins (for example, poly C _2-4 olefin resins such as polyethylene and polypropylene), acrylic resins (for example, acrylonitrile) -An acrylonitrile resin having an acrylonitrile unit such as a vinyl chloride copolymer), a vinyl resin, a polyester resin (for example, an aromatic polyester resin such as polyethylene terephthalate), a polyamide resin (for example, polyamide 6, polyamide) 66, aliphatic polyamide resins, alicyclic polyamide resins, aromatic polyamide resins, etc.), cellulose ester resins (for example, cellulose acetate, etc.), and the like. These thermoplastic resins can be used alone or in combination of two or more.

  Of these thermoplastic resins, vinyl resins are preferred. Examples of vinyl resins include polyvinyl alcohol resins, polyvinyl chloride resins (for example, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, vinyl chloride-acrylonitrile copolymers, etc.), polyvinylidene chloride resins (for example, Vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-vinyl acetate copolymer, etc.).

  In particular, in the present invention, a polyvinyl alcohol resin is preferable from the viewpoint of high rigidity and excellent soundproofing. In addition to polyvinyl alcohol (PVA), which is a homopolymer, for example, a copolymer in which a copolymer unit is introduced into the main chain or side chain, or a functional group is introduced by modification of the terminal or side chain. Modified products are also included. The method for introducing the copolymerized unit may be random or block polymerization to the main chain, or may be graft polymerized as a side chain. Usually random or graft polymerization. Furthermore, you may contain other resin (especially halogen-containing vinyl polymer) in the matrix comprised with the polyvinyl alcohol-type resin.

Examples of the copolymerizable monomer in the copolymer include α-olefins (eg, α-C _2-6 olefins such as ethylene, propylene, butene, hexene, etc.), vinyl ethers (eg, methyl vinyl ether, ethyl). C _1-6 alkyl vinyl ethers such as vinyl ether, propyl vinyl ether, butyl vinyl ether, C _2-6 alkanediol-vinyl ethers such as ethylene glycol vinyl ether, 1,3-propanediol vinyl ether, 1,4-butanediol vinyl ether, etc. ) Acrylic acid or derivatives thereof [e.g., (meth) acrylic acid or salts thereof, (meth) acrylic acid C _1-6 alkyl such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate Esters etc.], (meth) a Riruamido or a derivative thereof [e.g., (meth) acrylamide, N- methyl (meth) N-C _1-6 alkyl, such as acrylamide (meth) acrylamide, etc.], allyl esters (e.g., allyl acetate), alkyl allyl ethers (For example, C _1-6 alkyl-allyl ether such as propyl allyl ether, butyl allyl ether, hexyl allyl ether, etc.), N-vinylamides (eg, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, etc.) Alkenols (for example, C _3-10 alkenol such as 3-buten-1-ol and 4-penten-1-ol), vinyl silanes (for example, vinyl tri C _1-4 alkoxysilane such as vinyltrimethoxysilane) ), Unsaturated carboxylic acids [e.g. Anhydride) maleic acid, (anhydrous) itaconic acid, (anhydrous) polycarboxylic acid such as citraconic acid or its anhydride], sulfonic acid group-containing monomers (for example, ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfone) Acid, 2-acrylamido-2-methylpropanesulfonic acid, etc.), cationic group-containing monomers [eg, vinyloxytetra C _1-10 alkylammonium halides such as vinyloxyethyltrimethylammonium chloride; vinyloxyethyldimethylamine, etc. Vinyloxytri C _1-10 alkylamine; N-acrylamide tetra C _1-10 alkylammonium halide such as N-acrylamidoethyltrimethylammonium chloride; N-acrylamide diC _1-10 alkylamine such as N-acrylamidodimethylamine; A Such as Lil trimethylammonium chloride (meth) Arirutori C _1-10 alkyl ammonium halides; di C _1-3 alkylaryl amines, such as dimethyl allylamine; allyl C _1-3 alkyl amines such as allyl ethyl amine], halogen-containing vinyl monomer (For example, vinyl halides such as vinyl chloride, vinyl bromide and vinyl fluoride, and vinylidene halides such as vinylidene chloride, vinylidene bromide and vinylidene fluoride). These monomers can be used alone or in combination of two or more. Among these copolymerizable monomers, for example, C _2-4 olefins such as ethylene are _{widely used} from the viewpoint of improving fiber properties, and vinyl chloride, etc., from the viewpoint of improving heat resistance in automobile applications. Such as vinyl halide is widely used. The vinyl halide may be introduced by graft polymerization or the like.

  The proportion of copolymerized units can be selected from the range of 70 mol% or less in the polyvinyl alcohol-based resin, and is usually 50 mol% or less, preferably 30 mol% or less, more preferably 20 mol% or less (for example, 0.01 to 20 mol%). When a halogen-containing vinyl such as vinyl chloride is introduced by graft polymerization, or a halogen-containing vinyl polymer (polyvinyl chloride, etc.) is present in a fibril-like form in a matrix composed of a polyvinyl alcohol resin, The ratio of the vinyl halide unit (or vinyl halide polymer) is, for example, 10 to 70 mass%, preferably 20 to 60 mass%, more preferably 25 to 50 mass% (based on the total amount of the resin component). For example, about 30-40 mass%) may be sufficient.

  The viscosity average polymerization degree of the polyvinyl alcohol-based resin is, for example, about 500 to 4000, preferably about 1000 to 2500, and more preferably about 1200 to 2500. When the degree of polymerization is too low, the molecular chain is entangled and the fiber strength and water resistance are liable to be reduced by stretching. On the other hand, when the degree of polymerization is too high, the viscosity of the stock solution is remarkably increased, so the concentration of the PVA resin in the stock solution needs to be lowered, and productivity may be lowered. Furthermore, volume shrinkage increases due to dehydration, and it is difficult to obtain a shape with high flatness.

  The saponification degree of the polyvinyl alcohol-based resin is, for example, about 85 to 99.99%, preferably about 90 to 99.9%, and more preferably about 95 to 99.9% (particularly 96 to 99.9%). When the degree of saponification is too low, the thermal stability is lowered, and when the degree of saponification is too high, the productivity is lowered.

  A polyvinyl alcohol-type resin is obtained by a conventional method by saponifying the vinyl ester unit of a vinyl ester-type polymer. Examples of the vinyl compound monomer for forming the vinyl ester unit include vinyl formate, vinyl acetate, vinyl propionate, vinyl caprate, and vinyl laurate. These vinyl compound monomers can be used alone or in combination of two or more. Among these, lower aliphatic vinyl carboxylates such as vinyl acetate and vinyl propionate are preferable, and usually vinyl acetate is used.

  For thermoplastic resins, various additives used for fibers, such as stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), flame retardants, antistatic agents, colorants, lubricants, antibacterial agents, insecticides -You may contain an anti-mite agent, an anti-mold agent, a matting agent, an animal heat agent, a fragrance | flavor, a fluorescent whitening agent, a wetting agent, a plasticizer, a thickener, a dispersing agent, etc. These additives can be used alone or in combination of two or more.

  Of these additives, addition of a flame retardant or a plasticizer is effective for thermoplastic resins (for example, polyvinyl alcohol resins). Examples of the flame retardant include an inorganic acid or a salt thereof [for example, phosphoric acid, stannic acid, boric acid, or a metal salt thereof (for example, sodium stannate, magnesium stannate, zinc stannate, etc.), a metal compound, etc. (For example, metal oxides such as antimony trioxide, antimony tetraoxide, and antimony pentoxide, metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and tin hydroxide, and metal sulfides such as zinc sulfide and molybdenum sulfide) Etc. The plasticizer is added for the purpose of adjusting the melting point and the melt viscosity. Examples of the plasticizer include diglycerin, polyglycerin alkyl monocarboxylic acid esters, and compounds obtained by adding ethylene oxide and / or propylene oxide to glycols. It is done.

  Each of these additives can be used at a ratio of 50 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin, for example, a ratio of about 0.01 to 30 parts by mass, preferably about 0.1 to 20 parts by mass. It is.

  The fiber comprised with such a thermoplastic resin can be used individually or in combination of 2 or more types. Specific examples of preferable fibers include polyvinyl alcohol fibers such as vinylon fibers and polyclar fibers.

  The soundproof fiber of the present invention may contain a layered inorganic compound. The layered inorganic compound may be a natural or synthetic compound. Examples of layered inorganic compounds include smectite group clay minerals (for example, montmorillonite, beidellite, nontronite, saponite, hectorite, soconite, stevensite, etc.), vermiculite group clay minerals (for example, vermiculite, etc.), kaolin type minerals (for example, vermiculite) , Halloysite, kaolinite, enderite, dickite, etc.), phyllosilicates (eg, talc, pyrophyllite, mica, margarite, muscovite, phlogopite, tetracyllic mica, teniolite), jamonite Examples include group minerals (for example, antigolite), chlorite group minerals (for example, chlorite, cookite, and nanthite). These layered inorganic compounds can be used alone or in combination of two or more. Among these layered inorganic compounds, phyllosilicates such as mica and talc, smectite group clay minerals such as montmorillonite, etc. are widely used.

  The particle size of the layered inorganic compound can be appropriately selected according to the size of the spinning nozzle hole. For example, the average particle size is 0.01 to 30 μm, preferably 0.05 to 20 μm, more preferably about 0.1 to 10 μm. It is.

  The ratio of these layered inorganic compounds is, for example, about 0.01 to 30% by mass in the fiber, preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass (particularly 0.1 to 15% by mass). 10 mass%). If the proportion of the layered inorganic compound is too small, the productivity of high flatness fibers will not be improved, and the sound insulation effect of the layered inorganic compound will not be exhibited. On the other hand, when the proportion of the layered inorganic compound is too large, the ejection stability at the spinning nozzle is lowered, and the physical properties of the obtained fiber are also lowered.

  In the present invention, in a flat fiber, the layered inorganic compound may not be oriented, but usually it is often oriented. For example, the plane direction of the layered inorganic compound may be oriented in the flat plane direction of the fiber. When oriented in this way, it is considered that the sound insulation of the fiber is improved by the sound insulation effect of the layered inorganic compound.

  Such soundproofing fibers are preferably extremely fine from the viewpoint of sound absorption and light weight, and have a single fiber fineness of 5 dtex or less. The single fiber fineness may be, for example, about 0.001 to 5 dtex, preferably 0.01 to 4 dtex, more preferably about 0.1 to 3 dtex (particularly 0.5 to 3 dtex). If the single fiber fineness is too large, the sound absorption is lowered, and if it is too small, the productivity is lowered.

  The shape of the soundproofing fiber is a flat shape (for example, a slit (rectangular) shape, an elliptical shape, etc.), and preferably has a high flatness from the viewpoint of soundproofing. In the present invention, the cross-sectional flatness is 7 to 40, preferably 8 to 35, and more preferably 10 to 35 (particularly 12 to 35). If the cross-sectional flatness is too small, the soundproofing property is lowered, and if it is too large, the productivity is lowered. In the present invention, the cross-sectional flatness means the ratio of the major axis to the minor axis in the fiber cross section (cross section in the direction perpendicular to the fiber length direction).

  The thickness of the soundproof fiber is, for example, about 0.1 to 10 μm, preferably 0.3 to 5 μm, and more preferably about 1 to 4.5 μm (particularly 1.5 to 4 μm). When the thickness is not uniform, it means an average value, and the cross-sectional flatness is obtained based on this average value.

  The fiber length of the soundproofing fiber is not particularly limited and can be appropriately selected according to the form of the fiber assembly. However, when the nonwoven fabric is formed as the fiber assembly, it may be about 0.5 to 100 mm. For example, it is 1-50 mm, Preferably it is 2-30 mm, More preferably, it is about 3-10 mm.

[Method for producing soundproofing fiber]
As the method for producing the soundproof fiber, a conventional method can be selected according to the type of the fiber, and any method such as a wet spinning method, a dry spinning method, a dry and wet spinning method, or a melt spinning method may be used. In the case where the soundproofing fiber is a polyvinyl alcohol fiber, a wet spinning method is preferable because a fiber having high flatness can be easily formed. Further, as a method for forming a fiber having a flat shape, a fiber formed of a plurality of resin components having different solubility in a solvent may be a method of dividing by dissolving in a solvent, but soundproofing and productivity From this point, a method using a flat nozzle nozzle is preferable.

  The wet spinning method of polyvinyl alcohol resin includes an aqueous wet spinning method using an aqueous solvent (such as water) as a solvent and an organic solvent wet spinning method using an organic solvent. Therefore, an aqueous wet spinning method is usually used. In the water-based wet spinning method, for example, a polyvinyl alcohol-based resin is dissolved in water to prepare a spinning stock solution, and then the spinning stock solution is discharged from a nozzle hole into a coagulating bath to be solidified. As the coagulation bath, an aqueous solution containing salts having coagulation ability with respect to the spinning solution (for example, a saturated sodium sulfate aqueous solution) is usually used. In order to increase the strength of the obtained fiber, an aqueous solution of sodium sulfate containing caustic soda may be used as a coagulation bath by dissolving boric acid in the spinning dope.

  The layered inorganic compound may be contained in the spinning dope. When a layered inorganic compound is added, after the spinning dope has passed through the die, shrinkage and deformation of the formed fiber are suppressed, and flat fibers can be easily produced. In particular, when a layered inorganic compound is added, not only the flat shape corresponding to the shape of the die is maintained due to the presence of the layered inorganic compound, but also because the layered inorganic compound is oriented along the flat surface in the resin. It is possible to form a fiber having flatness higher than that of the flat shape. Therefore, the flat shape of the fiber can be controlled by the shape of the die and the ratio of the layered inorganic compound. In particular, in order to increase the cross-sectional flatness ratio, the ratio of the layered inorganic compound may be increased, or the ratio between the long side and the short side of the base slit may be increased.

  The shape of the single nozzle hole used for spinning is a slit (rectangular) shape so that the fiber has a flat shape. Specifically, the long side of the slit is about 100 to 2000 μm (preferably 150 to 1500 μm, more preferably 180 to 1000 μm), and the short side is about 10 to 200 μm (preferably 15 to 150 μm, more preferably 20 to 100 μm). There may be. Such a slit shape may be a shape in which the long end of the rectangle is semicircular, or a so-called “dogbone” shape in which the long end is circularly processed. The ratio of the long side to the short side of the nozzle single hole is usually the same as the cross-sectional flatness of the fiber, but the cross-sectional shape of the obtained fiber does not necessarily match the nozzle shape. For example, when a layered inorganic compound is used, it is possible to produce a fiber having flatness higher than the shape of the base, and therefore it is possible to use a base having a flatness lower than the flatness of the fiber. When the layered inorganic compound is used, the length ratio between the long side and the short side of the base slit is, for example, a range of long side / short side = 3/1 to 12/1, preferably about 4/1 to 10/1. It may be.

  The fiber solidified in the coagulation bath may be drawn with a roller and then stretched while still containing water. The magnification of wet stretching is, for example, about 2 to 5 times, preferably about 3 to 4 times. The wet-stretched fiber is dried in a constant length state in a hot air dryer of about 100 to 150 ° C. (preferably 120 to 140 ° C.), and subsequently about 200 to 250 ° C. (preferably 210 to 240 ° C.). Further, dry-heat drawing is performed 2 to 3 times in a hot air furnace to obtain a soundproof fiber constituted by the polyvinyl alcohol resin of the present invention. The ratio of dry heat stretching is 1.5 to 4 times, preferably about 2 to 3 times. In addition, you may use the obtained polyvinyl alcohol-type fiber as it is, and in order to improve water resistance etc., you may give the formalization process by formaldehyde further. The resulting soundproof fiber may be further cut to a fiber length in the above range when forming a nonwoven fabric.

[Soundproof material]
The soundproofing material of the present invention is composed of a fiber assembly including the soundproofing fibers. The fiber assembly may be a woven fabric such as a woven fabric or a knitted fabric, but a nonwoven fabric is preferable from the viewpoint of soundproofing and productivity. The ratio of the soundproofing fiber of the soundproofing material can be appropriately selected according to the production method, but is preferably at least 50% by mass (for example, 50 to 100% by mass) from the viewpoint of soundproofing, and is usually 60% by mass. % Or more (for example, 60 to 99% by mass), preferably 70% by mass or more (for example, 70 to 98% by mass), and more preferably about 80% by mass or more (for example, 80 to 95% by mass).

  The soundproofing material has a range that does not impair the soundproofing property of the soundproofing fiber, for example, 50% by weight or less (for example, 0.1 to 50% by weight) in the soundproofing material, preferably 30% by weight or less, and more preferably 10% by weight. % Of other fibers having a non-flat shape, for example, synthetic fibers, semi-synthetic fibers, regenerated fibers, natural fibers, and the like may be included.

  As a synthetic fiber, the fiber etc. which were comprised with the thermoplastic resin illustrated by the term of the said soundproof fiber can be illustrated, for example. Examples of semisynthetic fibers include acetate fibers such as triacetate fibers. Examples of the regenerated fiber include rayon, polynosic, cupra, and lyocell (for example, registered trademark name “Tencel”). Examples of natural fibers include cotton, wool (wool), silk, hemp and the like. Further, inorganic fibers such as glass fibers, carbon fibers, and metal fibers may be used.

  These other fibers can be used alone or in combination of two or more. Among these other fibers, fibers combined with polyvinyl alcohol fibers include polyester fibers such as polyethylene terephthalate fibers and polybutylene terephthalate fibers; polyolefin fibers such as polyethylene fibers and polypropylene fibers; and halogen-containing materials such as polyvinyl chloride fibers. Synthetic fibers such as vinyl fibers, semi-synthetic fibers such as triacetate fibers, natural fibers such as cotton, recycled fibers such as rayon and polynosic, inorganic fibers such as glass fibers and carbon fibers, and the like are preferable.

  The cross-sectional shape of other fibers is not particularly limited. For example, in addition to a round cross-section, an irregular cross-section (for example, a hollow shape, a polygonal shape, a 3-14 leaf shape, a T shape, an H shape, a V shape, etc.) It may be. The single fiber fineness and fiber length of the other fibers are not particularly limited, but are usually about the same as the soundproofing fiber.

  The ratio of the other fibers can be selected from a range of, for example, about 0 to 200 parts by mass with respect to 100 parts by mass of the soundproof fiber, but is preferably 0 to 100 parts by mass, and more preferably about 0 to 90 parts by mass. is there. The proportion of other fibers may be about 1 to 100 parts by mass (for example, 50 to 100 parts by mass) with respect to 100 parts by mass of the soundproofing fiber.

  The soundproof material may contain a binder composed of a thermoplastic resin and / or a thermosetting resin. These binders are heat-fusible binders such as hot melt adhesive resins such as polyolefin resins, acrylic resins, styrene resins, vinyl acetate resins, polyester resins, polyamide resins and polyurethane resins. The binder comprised by these may be sufficient. These binders can be used alone or in combination of two or more. Among binders having heat-fusibility properties, polyolefin resins (for example, polyethylene), polyester resins (for example, copolyester having an aliphatic dicarboxylic acid unit), polyamide resins (for example, polyamide 6 and polyamide 12) Binders composed of aliphatic polyamides and the like are preferred.

  Furthermore, in the present invention, a fibrous binder having these heat-fusible properties, in particular, a fibrous binder having a core-sheath structure having a heat-fusible resin as a sheath component may be used. For example, a fibrous binder having a polyester resin having a low melting point and heat-fusibility as a sheath component and a polyester resin having a melting point higher than that of the resin of the sheath component as a core component may be used. The cross-sectional shape of the fibrous binder is not particularly limited. For example, in addition to a round cross section, an irregular cross section (for example, a hollow shape, a flat shape, an elliptical shape, a polygonal shape, a 3-14 leaf shape, a T shape, an H shape) , V shape, dog bone (I shape), etc.). Although the single fiber fineness and fiber length of the fibrous binder are not particularly limited, they are usually about the same as the soundproofing fiber.

  The ratio of the binder is, for example, about 0 to 100 parts by weight, preferably 1 to 50 parts by weight, and more preferably 3 to 30 parts by weight (particularly 5 to 20 parts by weight) with respect to 100 parts by weight of the total of the fiber components. is there.

Soundproofing material of the present invention, from the viewpoint of both sound insulation and light weight, the average apparent density is about 0.01 to 0.5 g / cm ^3, preferably, 0.015~0.4g / cm ^3, More preferably, it is about 0.02 to 0.3 g / cm ³ (0.05 to 0.2 g / cm ³ ).

The basis weight of the soundproofing material is, for example, about 30 to 500 g / m ² , preferably about 50 to 500 g / m ² , more preferably about 80 to 450 g / m ² (particularly about 100 to 400 g / m ² ). The air permeability of the soundproofing material is, for example, 1 to 150 ml / cm ² / second, preferably ^{2 to} 100 ml / cm ² / second, more preferably 3 to 80 ml / cm ² / second (particularly 5 to 50 ml / cm ² / second). )

  The form of the soundproofing material is usually in the form of a sheet, and the thickness thereof may be appropriately selected according to the application, and can be selected from the range of about 0.1 to 100 mm, but is usually 0.5 to 50 mm, preferably 1 It is about -30 mm, More preferably, it is about 3-20 mm.

The soundproofing material of the present invention exhibits soundproofing properties over a frequency range (about 10 to 20000 Hz) that can be sensed as sound, and is usually used for sounds having a frequency of about 100 to 10,000 Hz. In particular, the soundproofing material of the present invention is effective for sound having a frequency of, for example, 200 to 5000 Hz, preferably 300 to 3000 Hz, more preferably 500 to 2500 Hz (particularly 500 to 1800 Hz). Specifically, the soundproofing material having a basis weight of 200 g / m ² may have a normal incident sound absorption coefficient of 0.25 or more (for example, 0.25 to 0.9) with respect to 1000 Hz sound, It is about 3 to 0.8, more preferably about 0.35 to 0.6. Furthermore, the normal incident sound absorption coefficient for sound of 1600 Hz may be 0.5 or more (for example, 0.5 to 0.99), preferably 0.6 to 0.95, more preferably 0.7 to 0. .9 or so.

[Production method of soundproof material]
The soundproofing material can be produced by a conventional method according to the type of the fiber assembly, using the soundproofing fiber. When the soundproofing material is a non-woven fabric, either a dry method or a wet method may be used.

In the case of the dry type, for example, the soundproof fiber is mechanically crimped, the fiber length is cut to about 20 to 100 mm, and carded to produce a web. If necessary, other fibers may be blended when producing the web. The obtained web can be treated by, for example, hydroentanglement, partial hot pressure fusion (such as hot embossing), mechanical compression (such as needle punch), and the like to obtain a dry nonwoven fabric. . In water entanglement, a high-pressure water flow of 3 MPa or more (for example, about 5 to 50 MPa) may be injected, and in needle punching, 40 lines / cm ² or more (for example, about 120 to 1000 lines / cm ² ). You may punch by density.

  In the case of wet processing, a base paper (web) can be produced by wet-making paper for soundproofing cut to a fiber length of about 2 to 20 mm together with a binder (for example, a fibrous binder). In paper making, other fibers may be mixed as needed. The obtained base paper may be a single sheet or a plurality of sheets (for example, about 2 to 5 sheets, preferably about 2 to 4 sheets) laminated as necessary, and processed by hydroentanglement to obtain a wet nonwoven fabric. it can. In hydroentanglement, specifically, using a high-pressure hydroentanglement machine, jetting a high-pressure water stream onto the nonwoven fabric improves the morphological stability of the nonwoven fabric by tangling the fibers. Let In the water flow entanglement, a high pressure water flow of 3 MPa or more (for example, about 5 to 50 MPa) may be injected. The passing speed of the hydroentanglement machine is, for example, 0.1 to 50 m / min, preferably 0.5 to 30 m / min, and more preferably about 1 to 10 m / min. Further, a wet nonwoven fabric containing fibrillated fibers may be produced by making a slurry containing fibers obtained by beating a soundproof fiber with a beater such as a Niagara beater, refiner, or pulper.

  Among these methods, wet manufacturing is preferable as the method for manufacturing the nonwoven fabric because the flat surfaces of the fibers are easily aligned and the productivity is high.

  Depending on the purpose, the obtained non-woven fabric may be subjected to post-processing treatment such as electrification processing, hydrophilization treatment such as plasma discharge treatment or corona discharge treatment, and may be further subjected to secondary processing.

  The soundproofing material of the present invention is useful for various applications that require soundproofing properties. For example, a vehicle (for example, a vehicle such as an automobile, an aircraft, etc.) or a building (for example, a building on a road, a factory house, Used for interior materials of equipment, housing, etc.) In particular, since the soundproofing material of the present invention has both high soundproofing properties and light weight, it is a soundproofing component for automobiles, such as feed insulators, dash outer insulators, undercover insulators, wheel house insulators, dash inner insulators, floor insulators. , Roof liner, rear per shell insulator, rear quarter insulator, and particularly useful as a roof liner (ceiling material) by taking advantage of its light weight.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. The manufacturing method of the flat vinylon fiber used in the Examples, and details of other fibers and binders are shown below. Further, in the examples, each physical property value was measured as follows. In the examples, “parts” and “%” are based on mass unless otherwise specified.

[Manufacturing method of flat vinylon]
(The flat vinylon fiber used in Example 1)
Spinning stock solution comprising an aqueous solution containing 15% by mass of PVA resin having an average degree of polymerization of 1700 and a saponification degree of 99.9% by mol and 0.24% by mass of a layered inorganic compound (manufactured by Coop Chemical Co., synthetic mica “MEB-3”) Was discharged into a coagulation bath of a saturated sodium sulfate aqueous solution from a rectangular slit type spinneret having a pore number of 4000, length of 30 μm × width of 170 μm, wound with a first roller, and then wet stretched 4 times. Dry at 130 ° C. Subsequently, dry heat drawing was performed twice at 230 ° C. to obtain a flat vinylon fiber having a single fiber fineness of 1.2 dtex and a cross-sectional flatness of 8. The obtained flat vinylon fiber was acetalized in an aqueous solution containing 5% by mass of formaldehyde and 10% by mass of sulfuric acid for 60 minutes.

  When the obtained flat vinylon fiber was observed with a transmission electron microscope, the flat surface of the synthetic mica was oriented in the flat surface direction of the fiber.

(Flat vinylon fibers used in Examples 2-4 and 7)
In the manufacturing method of the flat vinylon fiber used in Example 1, the flat vinylon fiber having a single fiber fineness of 1.2 dtex and a cross-sectional flatness of 15 was similarly used except that the addition amount of the layered inorganic compound was changed to 0.54% by mass. Manufactured.

  When the obtained flat vinylon fiber was observed with a transmission electron microscope, the flat surface of the synthetic mica was oriented in the flat surface direction of the fiber.

(Flat vinylon fiber used in Example 5)
In the manufacturing method of the flat vinylon fiber used in Example 1, the flat vinylon fiber having a single fiber fineness of 1.2 dtex and a cross-sectional flatness of 23 was similarly used except that the addition amount of the layered inorganic compound was changed to 0.8% by mass. Manufactured.

  When the obtained flat vinylon fiber was observed with a transmission electron microscope, the flat surface of the synthetic mica was oriented in the flat surface direction of the fiber.

(Flat vinylon fiber used in Example 6)
In the production method of the flat vinylon fiber used in Example 1, the amount of the layered inorganic compound was changed to 0.8% by mass, and the spinneret holes were 25 μm in length and 210 μm in width. A flat vinylon fiber having a fineness of 1.2 dtex and a cross-sectional flatness of 30 was produced.

  When the obtained flat vinylon fiber was observed with a transmission electron microscope, the flat surface of the synthetic mica was oriented in the flat surface direction of the fiber.

(Flat vinylon fiber used in Example 8)
In the production method of the flat vinylon fiber used in Example 1, the amount of the layered inorganic compound was changed to 0.8% by mass, and the spinneret holes were 55 μm in length and 300 μm in width. A flat vinylon fiber having a fineness of 4 dtex and a cross-sectional flatness of 23 was produced.

  When the obtained flat vinylon fiber was observed with a transmission electron microscope, the flat surface of the synthetic mica was oriented in the flat surface direction of the fiber.

(The flat vinylon fiber used in Comparative Examples 1 and 2)
In the production method of the flat vinylon fiber used in Example 1, a single fiber fineness of 1.2 dtex and a cross-sectional flatness of 2.5 were similarly obtained except that a spinneret having a round cross section was used without adding a layered inorganic compound. Flat vinylon fibers were produced.

[Other fibers and binders]
2.2T polyester fiber: Polyethylene terephthalate fiber having a single fiber fineness of 2.2 dtex, fiber length of 10 mm, and spherical section 1.4T polyester fiber: Single fiber fineness of 1.4 dtex, fiber length of 10 mm, polyethylene terephthalate fiber having a spherical section Binder fiber: A core-sheath type polyester fiber binder made of polyethylene terephthalate, which is a copolymerized polyester having a melting point of 110 ° C. of the resin constituting the sheath and not copolymerized with the resin constituting the core (made by Kuraray Co., Ltd., product) Name “N-720”, single fiber fineness 2.2 dtex, fiber length 10 mm).

[Single fiber fineness]
Ten fibers (single yarn) were selected at random from a magnified photograph of a nonwoven fabric sample taken at a magnification of 1000 times with a scanning electron microscope (SEM), and their short and long diameters were measured. The fiber fineness was determined.

[Section flatness]
Using a scanning electron microscope (SEM), the major axis and minor axis of the cross section of the fiber were measured and determined.

[Weave weight of non-woven fabric]
Measured according to JIS L1906 “General Long Fiber Nonwoven Fabric Test Method”.

[Apparent density of nonwoven fabric]
It was shown by the mass (g) of the nonwoven fabric with respect to the apparent volume (cm ³ ) of the nonwoven fabric.

[Air permeability of nonwoven fabric]
Measured according to JIS L1906 “General long fiber nonwoven fabric test method”.

[Non-woven fabric sound absorption]
The sound absorption coefficient measurement system using an acoustic impedance tube (manufactured by Bruel & Care Co., 2 microphone impedance tube 4206 type large measurement tube), the distance from the soundproof material surface on the sound source side to the rigid wall is set to 20 mm, 500 Hz, 1000 Hz A normal incident sound absorption coefficient of 1600 Hz was measured.

Example 1
90 parts of flat vinylon fiber with a single fiber fineness of 1.2 dtex, cross-sectional flatness of 8 and fiber length of 10 mm and 10 parts of binder fiber with a single fiber fineness of 2.2 dtex and fiber length of 10 mm are mixed in a two-sheet paper machine. Papermaking was performed to obtain a base paper with a basis weight of 67 g / m ² . Three layers of this base paper were stacked and subjected to hydroentanglement treatment (4.7 MPa, passage speed 10 m / min) to obtain a nonwoven fabric having a basis weight of 200, an apparent density and an air permeability. The results of measuring the sound absorption coefficient of the obtained nonwoven fabric are shown in Table 1.

Examples 2-8 and Comparative Examples 1-3
By adjusting the papermaking conditions using the fibers shown in Table 1, nonwoven fabrics having the characteristics shown in Table 1 were obtained. The results of measuring the sound absorption coefficient of the obtained nonwoven fabric are shown in Table 1.

  As is clear from the results in Table 1, the nonwoven fabric of the example containing flat vinylon fibers exhibits a high sound absorption rate, whereas the nonwoven fabric of the comparative example has a low sound absorption rate.

Claims (13)

  A soundproof fiber which is a fiber composed of a thermoplastic resin and has a single fiber fineness of 5 dtex or less and a cross-sectional flatness of 7 to 40.   The soundproof fiber according to claim 1, wherein the thermoplastic resin is a polyvinyl alcohol resin.   The soundproofing fiber according to claim 1, wherein the soundproofing fiber is composed of at least one selected from vinylon fiber and polyclar fiber.   Furthermore, the fiber for soundproofing of Claim 1 which contains a layered inorganic compound in the ratio of 0.01-30 mass% in a fiber, and the surface direction of the layered inorganic compound is orientated in the eccentric plane direction of the fiber.   A soundproof material comprising a fiber assembly including the soundproof fiber according to claim 1.   The soundproofing material according to claim 5, which is composed of a nonwoven fabric containing 50% by mass or more of soundproofing fibers.   Furthermore, the soundproofing material of Claim 5 containing the binder comprised by the at least 1 type selected from the thermoplastic resin and the thermosetting resin.   The soundproofing material according to claim 7, wherein the binder is a fibrous binder having heat-fusibility. 6. The soundproofing material according to claim 5, wherein the average apparent density is 0.01 to 0.5 g / cm < ³ >, the basis weight is 30 to 500 g / m < ² >, and the air permeability is 1 to 150 ml / cm < ² > / sec.   The method for producing a soundproof fiber according to claim 1 by spinning a thermoplastic resin.   The method according to claim 10, wherein the dope containing the polyvinyl alcohol-based resin and the layered inorganic compound is wet-spun.   A method for producing the soundproofing material according to claim 5, using the soundproofing fiber according to claim 1.   A soundproofing method using the soundproofing material according to claim 5.