MXPA06002011A

MXPA06002011A - Sound absorbing material

Info

Publication number: MXPA06002011A
Application number: MXPA/A/2006/002011A
Authority: MX
Inventors: Takayasu Akira; Yamamoto Tsutomu; Kosuge Kazahiko; Matsumura Mineaki
Original assignee: Du Ponttoray Company Ltd; Ichimura Sangyo Co Ltd; Takayasu Co Ltd
Priority date: 2003-08-25
Filing date: 2006-02-21
Publication date: 2006-12-13

Abstract

A sound absorbing material, characterized in that nonwoven fabrics having a weight of 150 to 800 g/m2 and a bulk density of 0.01 to 0.2 g/cm3 and skin materials having a permeability measured in accordance with JIS L-1096 of 50 cc/cm2/sec or less are laminated on each other.

Description

SOUND ABSORBING MATERIAL FIELD OF THE INVENTION The present invention relates to a sound absorbing material, more particularly to a sound absorbing material that is used in the fields of, for example, electrical products such as air conditioners, electric refrigerators, electric washing machines and electric lawn mowers.; transportation facilities such as vehicles, boats and boats, and airplanes; or construction materials such as construction wall materials, and civil engineering and construction machineries.

BACKGROUND OF THE INVENTION Sound absorbing materials are conventionally used for, for example, electrical products, building wall materials and vehicles. Particularly, for the purpose of preventing vehicles such as automobiles from generating noise by external acceleration or external parasitic noise, specifications are being adopted which require that the engines and transmissions be surrounded by acoustic shields. In Ref .: 169721 Generally, in the case of automobiles, such acoustic shielding need not only have excellent absorbency in noise, but also prevent the spread of fire to the seat of a driver in the event that a fire occurs in an engine housing, to a traffic accident, in view of the security assurance. Consequently, from the fire prevention point of view, there has been a demand for a sound absorbing and flame retardant material, excellent not only in sound absorbency, but also in fire safety. Furthermore, it is also desired that such sound absorbing, fire retardant material should not produce a toxic gas when it is burned. In addition to having sound absorbency and fire retardancy, it is desired that sound absorbing materials for vehicles such as automobiles, should be made of light and recyclable materials to achieve weight reduction of automobiles, and promote the recycled use of automobiles. Sound absorbing materials from cars that are crashed or scrapped. This is because the promotion of the recycling of various junk car parts reduces the amount of scrap industrial waste as much as possible, is considered important for the prevention of pollution. For these reasons described above, the Light non-woven fabrics and fire retardants are receiving attention as materials that meet the above requirements. In general, non-woven fire retardant fabrics are manufactured by, for example, the use of fire retardant fibers such as aramid fibers and police fibers as the main constituent synthetic fibers of non-woven fabrics, or the use of fibers Synthetics in which a fire retardant based on phosphoric acid or a fire retardant based on boric acid is mixed, or coated or impregnated nonwoven fabrics similar to sheets with a binder coating solution in which a flame retardant is dispersed. fire . For example, Japanese Patent Application Laid-Open Nos. 62-43336 and 62-43337 describe an interior material for manufactured vehicles, by applying an emulsion of vinyl chloride on the surface of a non-woven fabric mesh, measured by needle puncturing a network comprised of 95% by weight of a polyester fiber, a polypropylene fiber, or a mixture thereof, and 5% by weight of rayon fiber, by drying it to form a retardant resin coating of the fire, and by laminating a mesh of fiberglass on the surface covered with resin of the mesh of non-woven fabric, to unify the mesh of fiberglass with the meshing nonwoven fiber. Such material for interiors for vehicles, is excellent in the delay of the fire but poor in capacity of recycling, because the mesh of non-woven fabric is linked with the fiberglass mesh. In addition, the interior material for vehicles has a problem since there is a fear that the interior material will produce dioxin when it is incinerated. In addition, Japanese Patent Application Laid-Open No. 9-59857 describes a non-woven, fire-retardant fabric made by laminating nonwoven web layers of a shredded fire retardant stone on both surfaces of the network layers. nonwoven and a polyester fiber, in such a way that the amount of the non-woven network layers of the discontinuous fire-retardant fiber, becomes 50% by weight or more of the total amount of a resulting non-woven fabric, and the constituent fibers are intermingled with each other between the adjacent network layers. Japanese Patent Application Laid-Open No. 2002-348766 discloses a fire retardant sheet material made by needle puncturing a non-woven web by mixing a polyester fiber with a fire retardant rayon fiber, or fiber modacrylic (which is obtained by copolymerization of acrylonitrile with monomer based on vinyl chloride, as a fire retardant) and additionally it is joined by stitching by points to it. Japanese Patent Application Laid-Open No. 2000-328418 discloses a non-woven, fire-retardant, halogen-free fabric manufactured by mixing a fiber network containing a cellulose-based fiber, a fiber based on polyvinyl alcohol , and a fire retardant polyester fire retardant fabric, with an acrylic resin binder. These non-woven fabrics described in the above patent documents are excellent in fire retardancy, but poor in sound absorbency. As an example of a sound absorbing, fire retardant material, Japanese Patent Application Laid-Open No. 2002-287767 discloses a sound absorbing material for manufactured vehicles, by integrally coating and molding a sound absorbing material. , similar to a mesh, in which rock wool, a glass fiber and a polyester fiber are unevenly oriented in a mixed state, and these fibers are bonded together with a fibrous binder such as a low point polyester fiber of melting, and a surface material that is comprised of a non-woven fabric, based on polyester fibers, subjected to waterproof, oil-proof and fire-proof treatment. In addition, Japanese Patent Application Laid-Open No. 2002-161465 describes a sound absorbing material made by laminating a non-woven fiber of fire retardant polyester filaments, as a surface material on a surface of a laminated structure comprising a non-woven fabric, blown in molten form, and a non-woven fabric. polyester woven, unified by needle puncture. In both of the above techniques, these sound-absorbing materials, fire retardants, are manufactured by unifying a sound-absorbing material with a fire retardant surface material. According to the first techniques, as described above, since the sound absorbing material similar to a mesh and that of the surface material covering the sound absorbing material are integrally molded, it is necessary to carry out the thermocompression molding to a temperature of a melting point of the fibrous binder or a higher temperature, which complicates the manufacturing process thereof. Furthermore, in a case where the polyester fiber contains a halogen-based fire retardant, there is a fear that the sound-absorbing material will produce a toxic gas when it is burned. On the other hand, the sound absorbing materials according to the latest techniques have a drawback that they are poor in fire retardancy. In view of the problems described above, an object of the present invention is to provide a sound absorbing material that is advantageous in sound absorbency, that has fire retardation without using a fire retardant, that does not produce dripping of a liquid molten material when a constituent fiber is melted, that has low shrinkage capacity, and that is excellent in safety, cost efficiency and recycling capacity. In order to achieve the above objective, the present inventors have intensively investigated, and as a result they found that by layering a surface material having an air permeability not greater than 50 c / cm2 / second, measured according to JIS L -1096 on a non-woven fabric, with a mass per unit area of 150 to 800 g / m2 and a bulk density of 0.01 to 0.2 g / cm3, especially such a non-woven fabric obtained by intermixing the fibers by needle puncture or water jet puncture instead of thermal fusion, it is possible to obtain an excellent sound absorbing material in sound absorbency, fire retardancy, recyclability, and maneuverability. This finding has led to the termination of the present invention. Specifically, the present invention is directed to a sound absorbing material having a layered structure comprising a non-woven fabric with a mass per unit area of 150 to 800 g / m2 and an apparent density of 0.01 to 0.2 g / cm3, and a surface material with an air permeability not higher than 50 cc / cm2 / second measured according to JIS L-1096 . In the sound absorbing material of the present invention, the non-woven fabric is preferably a fabric in which a discontinuous thermoplastic fiber and a heat-resistant discontinuous fiber with a LOI value of not less than 25 are intermixed with each other. The mass proportion of the thermoplastic discontinuous fiber and the heat resistant batch fiber is more preferably in the range of 95: 5 to 55:45, more preferably in the range of 85:15 to 55:45. The sound absorbing material having such a structure is a sound-absorbing, fire-retardant material, excellent in flame retardancy, as well as in sound absorbency. Further, in the sound absorbing material of the present invention, the thermoplastic discontinuous fibers are preferably at least one type of discontinuous fibers selected from the group consisting of a polyester fiber, a polypropylene fiber and a nylon fiber, and the Heat-resistant discontinuous fiber is preferably at least one type of discontinuous fibers selected from the group consisting of an aramid fiber, a polyphenylene sulfide fiber, a fiber of polybenzocazole, a polybenzothiazole fiber, a polybenzimidazole fiber, a polyether ether ketone fiber, a polyarylate fiber, a polyimide fiber, a fluoride fiber, and a flame resistant fiber. More preferably, the discontinuous thermoplastic fiber is a discontinuous polyester fiber, and the heat resistant discontinuous fiber is a discontinuous aramid fiber. In addition, in the sound absorbing material of the present invention, the surface material is preferably a non-woven fabric, spun-bonded filaments, or a non-woven fabric of staple fibers spread in wet form. The nonwoven fabric and the surface material may be comprised of the same type of synthetic fiber. In addition, in the sound absorbing material of the present invention, the surface material is preferably a nonwoven, wet laid fabric comprised of a heat resistant fiber with a LOI value of not less than 25 or a wet laid nonwoven fabric comprised of a heat resistant fiber with a LOI value of not less than 25, and a silicate mineral (e.g., mica). By using such a wet-laid nonwoven fabric as the surface material, it is possible to obtain an excellent sound absorbing material in sound absorbency and fire resistance. In addition, in the sound absorbing material of the present invention, as the surface material is also preferably used a clean paper with no more than 500 dust particles, with a particle diameter of not less than 0.3 μm per .0028 m3 (0.1 cubic foot) when subjected to measurement by the method of rotating drum according to JIS B-9923 6.2 (1.2). By using such clean paper as the surface material, it is possible to obtain a sound absorbing material that is excellent in sound absorbency and fire retardancy, and has low dust generation properties. In addition, the non-woven fabric and the surface material are preferably layered together in a state where they are bonded together. In this case, the number of bonding points of the non-woven fabric and the surface material is preferably not more than 30 dots / cm 2, and the ratio of the total surface area of the bonding points to the total surface area of the bonding points , and non-union points is preferably not greater than 30%. In addition, the sound absorbing material of the present invention, the non-woven fabric may be in the form of a polyhedron or a column or a cylinder having a curved surface. In the first case, the surface material can be placed in layers on two or more sides of the polyhedron. In the latter case, the surface material can be laid in layers on the curved surface of the column or the cylinder. For example, a sound-absorbing material in which the surface material is laid in layers on both surfaces of a non-woven hexahedral fabric (eg, a non-woven, rectangular parallelepiped fabric) can be mentioned. The sound absorbing material having such a structure is improved in loss of sound transmission, so that the sound tool as well as the sound absorbency are improved. Further, in the present invention, the sound absorbing material can have a multi-layered structure comprising one or more layers of the non-woven fabric and one or more layers of the surface material, wherein these layers are joined to one another. The sound absorbing material having such structure is improved in sound absorbency at low frequencies. The sound absorbing material described above can be suitably used as a sound absorbing material for interior or exterior materials of vehicles, lawn mowers and breakers.

DESCRIPTION OF THE INVENTION According to the present invention, it is possible to provide an excellent sound absorbing material in sound absorbance (for example, absorption coefficients). of sound of normal incidence, coefficients of absorption of sound in chamber of reverberation), delay of the fire, capacity of recycling, and maneuverability to low cost. In addition, the use of a non-woven fabric obtained by intermixing a discontinuous thermoplastic fiber with a heat resistant discontinuous fiber makes it possible to provide a high security sound absorbing material which does not drip a liquid molten material when it. Constituent fibers are melted, which has low shrinkage capacity, and does not produce toxic gas when burned.

DETAILED DESCRIPTION OF THE INVENTION A sound absorbing material according to the present invention has a layered structure comprising a non-woven fabric with a mass per unit area of 150 to 800 g / m2 and a bulk density of 0.01 to 0.2 g / cm3 and a material surface with an air permeability not higher than 50 cc / cm2 / second, measured according to JIS L-1096. The non-woven fabric to be used in the present invention can be either a discontinuous fiber non-woven fabric or a non-woven filament fabric, as long as it has a mass per unit area of 150 to 800 g / m2 and an apparent density of 0.01 to 0.2 g / cm3. The examples of such a non-woven fabric include non-woven, needle-punched fabrics, non-woven fabrics perforated by water jet, non-woven fabrics perforated in molten form, spunbonded non-woven fabrics, and non-woven fabrics knitted together. Among them, non-woven fabrics pierced with needle and non-woven fabrics pierced by water jet are preferably used, and non-woven fabrics pierced with needle are particularly preferably used. The raw felt can also be used as the non-woven fabric. In the present invention, the cross-sectional shape of a constituent fiber of the non-woven fabric is not particularly limited, and the constituent fiber can have either a perfect circular cross-sectional shape or a modified cross-sectional shape. Examples of the modified form in cross section include the oval, hollow, X, Y, T, L, star, leaf (eg, clover, four leaf clover, five leaf clover), and other polyangular shapes (for example, triangular, quadrangular, pentangular, hexagonal). Further, in the present invention, the constituent fiber of the non-woven fabric is a natural fiber or a synthetic fiber, but a synthetic fabric is preferably used from the standpoint of durability. The examples of the synthetic fiber include thermoplastic fibers such as polyether fiber, a polyamide fiber (e.g., a nylon fiber), an acrylic fiber, and a polyolefin fiber (for example, a polypropylene fiber, a polyethylene fiber). Such fibers can be manufactured from raw materials thereof according to a well-known method such as wet spinning, dry spinning, or spinning in molten form. Among these synthetic fibers, a polyester fiber, a polypropylene fiber, and a nylon fiber are preferably used because they are excellent in durability and abrasion resistance. Particularly, a polyester fiber is more preferably used because a raw material thereof, ie the polyester can be obtained by thermal melting using polyester non-woven fabrics and the polyester obtained in this way can be easily recycled, and therefore a polyester fiber can be economically manufactured. In addition, non-woven fabrics made from a polyester fiber have good texture and moldability. Such thermoplastic fibers can be partially or completely made of a reused material (recovered or regenerated fibers).

- In particular, recycled fibers from recovered fibers, once used for interior or exterior materials of vehicles, can be properly used. The polyester fiber described above is not particularly limited, as long as it is made from a polyester resin. Such a polyester resin is not particularly limited, so long as it is a polymeric resin comprising repeating units containing ester linkages, and may be one comprising ethylene terephthalate as the main repeating units of a dicarboxylic acid component and a glycol component . Alternatively, the polyester fiber can be a biodegradable polyester fiber made of polycaprolactone, polyethylene succinate, polybutylene succinate, polyethylene adipate, polybutylene adipate, polyethylene succinate / adipate copolymer or polylactic acid, or a synthesized polyester fabric. by copolymerization such as a polyester as a main component with another dicarboxylic acid and / or glycol. 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 glycol, tetramethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. The dicarboxylic acid component can be partially replaced by adipic acid, sebacic acid, dimeric acid, sulphonic acid, or isophthalic acid substituted with metal. In addition, the glycol component can be partially replaced by diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, or polyalkylene glycol. The polyester fiber is generally manufactured using a polyester resin according to a well known spinning method, such as spinning in molten form. Examples of such a polyester fiber include a polyethylene terephthalate (PET) fiber, a polybutylene terephthalate fiber (PBT), a polyethylene phthalate fiber.

(PEN), a polycyclohexylenedimethylene terephthalate fiber (PCT), a polytrimethylene terephthalate fiber (PTT), and a polytrimethylene naphthalate fiber (PTN). Among them, a polyethylene terephthalate (PET) fiber is preferably used. The polyethylene terephthalate fiber may contain, for example, conventional antioxidants, chelating agents, ion exchange agents, color protection agents, waxes, silicone oil, or various surfactants, as well as particles such as various inorganic particles, by example, titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, and zirconium acid, crosslinked polymer particles, and various metal particles. Polypropylene fiber is not particularly limited, as long as it is made from a resin of polypropylene. The polypropylene resin is not particularly limited, as long as it is a polymeric resin comprising repeating units containing the following structure: -CH (CH 3) CH 2 -. Examples of such a polypropylene resin include polypropylene resins and propylene-olefin copolymer resins, such as a propylene-ethylene copolymer resin. The polypropylene fiber is manufactured using a polypropylene resin according to a well-known spinning method, such as spinning in molten form. In addition, the polypropylene fiber can contain the various aforementioned additives, which can be added to the polyester fiber. Examples of the nylon fiber include fibers made from nylon resins or nylon copolymer resins such as polycaproamide (nylon 6), polyhexamethyleneadipamide (nylon 66), polytetramethyleneadipamide (nylon 46), polyhexamethylene sebacamide (nylon 610), polyhexamethylenedondemide (nylon 612) ), polyundecanamide.

(Nylon 11), Polidodecanamide (Nylon 12), Poly (m-xyleneadipamide) (Nylon MXD6), Polyhexamethyleneterephthalamide (6T nylon), polyhexamethylene isophthalamide (61 nylon), poly (xylene) dipamide (Nylon XD6), polycaproamide / poly (hexamethyleneterephthalamide) copolymer (nylon 6 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon) 66 / 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66 / '61), polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66/61/6), polyhexamethyleneterephthalamide / polyhexamethylene phosphthalamide copolymer (6T / 6L nylon), polyhexamethylene terephthalamide copolymer / polidodecanamide (6T / 12 nylon), polyhexamethyleneadipamide / polyhexamethyleneterephthalamide / poly hexamethylenebisophthalamide copolymer (nylon 66 / 6T / 6I), and polyhexamethyleneterephthalamide / poly-2-methylpentamethyleneterephthalamide copolymer (6T / M5T nylon). The nylon fiber is manufactured using such nylon resin according to a well-known method, such as melt spinning. In addition, the nylon fiber can contain the aforementioned additives that can be added to the polyester fiber. The length of the fiber and the fineness of the thermoplastic fiber are not particularly limited, and are appropriately determined according to the compatibility with other synthetic fibers or the uses of the resulting non-woven fire retardant fabrics. However, the The length of the thermoplastic fiber is preferably 10 mm or longer. The thermoplastic fiber can be either a filament or a discontinuous fiber. In the case of a discontinuous fiber, the length of the fiber is preferably 10 to 100 mm, particularly and preferably 20 to 80 mm. By interlocking a discontinuous fiber having a fiber length of 10 mm or more to make a non-woven fabric, it is possible to prevent the discontinuous fiber from detaching from the non-woven fabric. A longer fiber length makes the sound absorbency of the non-woven fabric better, but it tends to make the spinning capacity poor (for example, by a carding machine) and the retardation of the fire. Therefore, the fiber length of the thermoplastic discontinuous fiber is preferably 100 mm or less. The fineness of the thermoplastic fiber is 0.5 to 30 dtex, preferably 1.0 to 20 dtex, particularly preferably 1.0 to 10 dtex. The thermoplastic discontinuous fibers mentioned above can be used alone or in combination of two or more types thereof. For example, the thermoplastic staple fibers which are of the same type but are different in fineness or in fiber length can be mixed, or the thermoplastic staple fibers which are different in type as well as in fineness or fiber length, can be mixed. In any case, the proportion of The mixing of these discontinuous fibers is not particularly limited, and may be appropriately determined according to the uses or purposes of the resulting non-woven fabrics. In order to obtain a non-woven fabric, more fire retardant, the thermoplastic discontinuous fiber is preferably entangled and unified with a discontinuous fire resistant fiber. Fire-resistant batch fiber has a LOI (limiting oxygen index) value of not less than 25, and does not include fibers that are made fire retardant by the addition of a fire retardant, such as a fire retardant rayon fiber , a fire retardant vinyl fiber, and a modacrylic fiber. Here, a LOI value means the same minimum oxygen concentration required to sustain the combustion of 5 cm or more of a sample, and is measured according to JIS L 1091. By the use of such heat-resistant batch fiber having a value LOI not less than 25, it is possible to impart retardation of the fire to the non-woven fabric. However, in order to obtain a non-woven fabric even more fire retardant, a heat-resistant discontinuous fiber having a LOI value of not less than 28 is preferably used. The heat-resistant batch fiber that is preferably used in the present invention is superior to the discontinuous thermoplastic fiber since it it has less shrinkage capacity, and therefore a resulting non-woven fabric is not easily melted and shrunk when burned. Particularly, such heat-resistant batch fiber preferably has a dry heat shrinkage of not more than 1% at 280 ° C. Specific examples of such heat resistant batch fiber include discontinuous fibers obtained by, for example, cutting at least one type of heat resistant organic fibers selected from the group consisting of an aramid fiber, a polyphenylene sulfide fiber, a polybenzoxazole fiber, a polybenzothiazole fiber, a polybenzimidazole fiber, a polyether ether ketone fiber, a polyarylate fiber, a polyamide fiber, a fluoride fiber, and a fire resistant fiber such as to have a length of desired fiber. These heat-resistant staple fibers include those conventionally known or manufactured according to well-known methods or method based on these well-known methods, and all of them can be used. Here, the fire-resistant fiber is mainly a fiber manufactured by sintering an acrylic fiber of 200 to 500 ° C in an active atmosphere such as air, that is, a carbon fiber precursor. For example, a fire-resistant fiber manufactured by Asahi Kasei under the trade name "LASTAN®" and a fire-resistant fiber manufactured by Toho Tenax under the trade name of "Pyromex®", can be mentioned. Among these heat resistant organic fibers, at least one type of organic fibers selected from the group consisting of an aramid fiber, a polyphenylene sulfide fiber, a polybenzoxazole fiber, a polyether ether ketone fiber, a fiber of polyarylate, and a fire-resistant fiber, is preferably used from the standpoint of low shrinkage capacity and susceptibility to treatment. Particularly, an aramid fiber is preferably used. Aramid fiber includes a para-aramid fiber and a meta-aramid fiber. Particularly, a para-aramid fiber is preferably used from the standpoint of low heat shrink capacity. Examples of the para-aramid fiber to be used include commercially available products such as a polyparaphenylene terephthalamide fiber (manufactured by EI DU PONT and DU PONT-TORAY Co., Ltd., under the trade name of nKEVLARR) and a co-poly-para-phenylene-3,4'-oxydiphenylene terephthalamide fiber (manufactured by TEIJIN under the tradename "TECHNORA®"). Such aramid fiber may have a film former, a silane coupling agent, and a surfactant on the surface or on the inside of the same The amount of solid matter of these surface treatment agents coupled to the aramid fiber is preferably in the range of 0.01 to 20% by mass with respect to the amount of the aramid fiber. The length and fineness of the heat resistant discontinuous fiber type fiber is not particularly limited, and are appropriately determined according to the compatibility with the discontinuous thermoplastic fiber used together, or the uses of a resulting sound absorbing material. The fineness of the heat-resistant batch fiber is from 0.1 to 50 dtex, preferably from 0.3 to 30 dtex, more preferably from 0.5 to 15 dtex, particularly and preferably 1.0 to 10 dtex. The fire retardant mechanism in the non-woven fabric according to the present invention is not clear, but it can be considered that the heat-resistant discontinuous fiber, entangled with the thermoplastic discontinuous fiber, has the function of inhibiting the combustion of the fiber discontinuous thermoplastic. The fiber length of the heat-resistant batch fiber is not particularly limited, but is preferably from 20 to 100 mm, particularly preferably from 40 to 80 mm, in view of fire retardancy and productivity. The heat-resistant staple fibers mentioned above can be used alone or in combination with two or more types of them. For example, the heat resistant staple fibers which are of the same type but are different in fineness or in fiber length, can be blended or heat resistant staple fibers which are different in type as well as in fineness or fiber length, They can be mixed. In any case, the mixing ratio of these discontinuous fibers is not particularly limited, and may be appropriately determined according to the uses or purposes of a resulting sound absorbing material. The thermoplastic discontinuous fiber and heat resistant batch fiber to be used in the present invention are preferably mixed in a mass ratio of 95: 5 to 55:45. If the proportion exceeds 95% by mass, the retardation of the flame of the non-woven fabric is not sufficient, so that dripping is likely to occur. That is, by allowing a network to contain 5% by mass or more of the heat-resistant batch fiber and the interlacing of the heat-resistant batch fiber with the thermoplastic batch fiber, it is possible to prevent the batch of thermoplastic batch fiber from being consumed by combustion. and melted. On the other hand, if the proportion is less than 55% by mass, the non-woven fabric is excellent in retarding the flame but poor in treatment capacity, which allows the non-woven fabric to have a desired size, thereby reduce economic efficiency. Therefore, from the point of view of flame retardancy and treatment capacity, the mass proportion of the thermoplastic discontinuous fiber and the heat resistant discontinuous fiber, is more preferably from 88:12 to 55:45, preferably 85. : 15 to 55:45, most preferably 85:15 to 65:35. In the present invention, in order to improve the abrasion resistance and sound absorption properties of the non-woven fabric, it is preferred that the thermoplastic discontinuous fiber contain a fine denier thermoplastic discontinuous fiber. As a fine denier thermoplastic discontinuous fiber, at least one type of fibers selected from the aforementioned polyester fiber, polypropylene fiber, and polyethylene fiber, a low density polyethylene lining fiber, and a fiber of ethylene-vinyl acetate copolymer. The fineness of the fine denier thermoplastic discontinuous fiber to be used in the present invention is generally 0.1 to 15 dtex, preferably 0.5 to 6.6 dtex, particularly preferably 1.1 to 3.3 dtex. If the fineness of the fine denier thermoplastic discontinuous fiber is too small, the processing capacity becomes poor. On the other hand, if the fineness of the fine denier thermoplastic discontinuous fiber is too large, the sound absorption properties deteriorate. The length of the fine denier thermoplastic discontinuous fiber is not particularly limited, and may be appropriately determined according to the compatibility with the heat-resistant batch fiber used, and the uses of a resulting sound absorbing material. However, the fiber length of the fine denier thermoplastic discontinuous fiber is in general and preferably 10 to 100 mm, particularly preferably 20 to 80 mm. In a case where the fine denier thermoplastic discontinuous fiber is mixed in a network, the mixing ratio of the fine denier thermoplastic discontinuous fiber is preferably 30 to 70% by mass, more preferably 30 to 50% by mass with respect to to the total amount of the discontinuous thermoplastic fiber. In the present invention, the weight of the non-woven fabric is 150 to 800 g / m2. If the weight of the non-woven fiber is too small, the workability during manufacture becomes deficient so that, for example, the shape retention properties of a network layer deteriorate. On the other hand, if the weight of the non-woven fabric is too large, the energy required to interlock the fibers is increased or the interlacing of the fibers is insufficiently carried out, so that a disadvantage such as deformation occurs when the - nonwoven is processed. It should be noted that a network can be formed using a conventional ray-forming machine, according to a conventional method of network formation. For example, a mixture of the thermoplastic discontinuous fiber and the heat resistant discontinuous fiber is subjected to carding in a carding machine to form a network. The non-woven fabric to be preferably used in the present invention can be formed by, for example, needle piercing or water jetting a net obtained by mixing the discontinuous thermoplastic fiber with the discontinuous fiber resistant to the heat, to intertwine and unify the fibers with each other. By subjecting the network to the perforation treatment to entangle the fibers with one another, it is possible to improve the abrasion resistance of the non-woven fabric. Nail or both of the surfaces of the network can be subjected to needle piercing. At this time, if the density of the needle perforation is too low, the abrasion resistance of the non-woven fabric becomes insufficient. On the other hand, if the needle-piercing density is too high, the bulk density and the air volume ratio of the non-woven fabric decrease, thereby deteriorating the properties of the fabric. thermal insulation and the sound absorption properties of the non-woven fabric. Therefore, the propagation density with water is preferably 50 to 300 perforations / cm2, more preferably 50 to 100 perforations / cm2. In the present invention, needle drilling can be carried out using a conventional water drilling machine, according to a conventional needle drilling method. Water jet drilling was carried out according to a conventional method of water jet drilling using, for example, a water jet drilling machine to spray the high pressure water flow from 90 to 250 kg / cm2G from a plurality of nozzles having a diameter of 0.05 to 2.0 mm and aligned in a line or in a plurality of lines at intervals of 0.3 to 10 mm. The distance between the nozzles and a net is preferably approximately 1 to 10 cm. The network subjected to needle drilling or water jet drilling can be dried in the conventional manner and then, if necessary, heat hardened. In a case where the non-woven fabric is comprised of a discontinuous fiber, if the apparent density thereof is too low, the fire retardancy, the thermal insulation, and the absorbency of the sound deteriorate. For other Part, if the apparent density of the same is too high, the retardation of the fire, the resistance to the abrasion and the handling capacity are deteriorated. Therefore, it is necessary that the non-woven fabric of the discontinuous fiber have a bulk density of 0.01 to 0.2 g / cm3. Preferably, the bulk density of the discontinuous fiber nonwoven fabric is 0.01 to 0.1 g / cm 3, more preferably 0.02 to 0.08 g / cm 3, still more preferably 0.02 to 0.05 g / cm 3. By controlling the bulk density of the non-woven fabric to control the proportion of air (oxygen) contained in the non-woven fabric within a certain range, it is possible to impart excellent fire retardancy, thermal insulation, and sound absorbency to the non-woven fabric. woven. Further, in the present invention, in a case where heat resistance or durability is of importance to the sound absorbing material, the nonwoven fabric is preferably comprised of a heat resistant fiber. The heat resistant fiber can be either a discontinuous fiber or a filament. Examples of such heat resistant fiber include the aforementioned heat resistant organic fibers. In this case, the non-woven fabric is usually manufactured using a heat-resistant fiber according to a well-known method. In the present invention, a thicker nonwoven fabric makes the sound absorbency better, but the thickness of the non-woven fabric is preferably from 2 to 100 mm, more preferably from 3 to 50 mm, even more preferably from 5 to 30 mm, from the standpoint of, for example, economy efficiency, handling ability, and space that will be reserved for the sound absorbing material. As described above, the sound absorbing material according to the present invention has a layered structure comprising the non-woven fabric and the surface material. The surface material needs to have an air permeability not higher than 50 cc / cm2 / second, measured according to JIS L-1096. There is no lower limit for the air permeability of the surface material, but the air permeability is preferably 0.01 to 50 cc / cm2 / second, particularly and preferably 0.01 to 30 cc / cm2 / second. If the air permeability exceeds 50 cc / cm2 / second, the sound absorbency of the sound absorbing material is deteriorated. The constituent material of the surface of the material is not particularly limited, and for example, the aforementioned materials for the non-woven fabric can be used. The surface material may be in the form of a cloth or a film. Examples of fabric include non-woven fabrics (including clean paper and polyester paper), woven fabrics, and knitted fabrics. Examples of films include polyester films. The The constituent fiber of such a fabric can be either a discontinuous fiber or a filament. In a case where a fabric is used as the surface material, the surface material of the non-woven fabric placed in layers on the surface material is made from the same material or from different materials. For example, in a case where the sound absorbing material according to the present invention is used as an interior material in vehicles, the surface material and the non-woven fabric lying in layers on the surface material are preferably made from the same material. . This is because in this case, a large amount of sound absorbing material is used and the sound absorbing material that is to be used as a vehicle interior material, has to be recyclable. For example, in a case where the nonwoven fabric contains a polyester material, the surface material is preferably made of a polyester. Preferred examples of the surface material include spunbonded nonwoven webs, dry laid nonwoven webs, and wet laid nonwoven webs. Particularly, spunbond non-woven fabrics and wet-laid non-woven staple fibers are preferably used. Non-woven fabrics of filaments joined by spinning, are manufactured by a spinning method. Among such non-woven fabrics of spunbond filaments, those obtained by partially joining the fabrics together by means of a thermal bond to integrate a network, are particularly preferable. As such, a non-woven fabric, for example, a commercially available non-woven polyester nonwoven fabric (manufactured by TORAY Industries, Inc. under the tradename "Axtar") can be used. As a non-woven fabric of dry-laid staple fibers, one manufactured by needle-piercing a network is preferably used. Examples of the non-woven fabric of wet-laid staple fibers include paper and felt made from staple fibers, pulp, or staple fibers by a papermaking method. In the present invention, a non-woven fabric comprised of a heat-resistant fiber with a LOI value of not less than 25 and a silicate mineral can be used as the surface material, and this non-woven fabric is preferably a non-woven fabric laid on damp. Such a preferred non-woven fabric can be manufactured "using a heat-resistant fiber with an LOI value of less than 25, and a silicate mineral according to a well-known wet method." Heat-resistant fiber with a LOI value not less than 25"can be a discontinuous fiber, where the LOI value definition is the same as that described above. Examples of the heat resistant fiber include the aforementioned heat resistant organic fibers. As the silicate mineral, mica is preferably used. Specific examples of mica include white mica, bronze mica, black mica, and artificial bronze mica. The amount of the silicate mineral to be used is from 5 to 70% by mass, preferably from 10 to 40% by mass with respect to the amount of the surface material. The preferred laid nonwoven fabric to be used as the surface material is preferably comprised of a heat resistant discontinuous fiber with an LOI value less than 25. Examples of such heat resistant batch fiber include staple fibers heat resistant mentioned above. Among these heat resistant staple fibers, a discontinuous aramid fiber is preferably used, and a discontinuous para-aramid fiber is more preferably used. Alternatively, the wet laid nonwoven fabric can be a nonwoven fabric comprised of a heat resistant discontinuous fiber with a LOI value of not less than 25, and a silicate mineral. Such a wet-laid non-woven fabric is manufactured according to a well-known method of wet-based papermaking, using a heat-resistant batch fiber, with a LOI value of not less than 25 and using a heat-resistant batch fiber with a LOI value of not less than 25 and a silicate mineral. As the silicate mineral, mica is preferably used. Specific examples of mica include white mica, bronze mica, black mica, and artificial bronze mica. The amount of the silicate mineral to be used is from 5 to 70% by mass, preferably from 10 to 40% by mass with respect to the amount of the surface material. The nonwoven fabric to be used as the surface material is preferably clean paper whose total number of dust particles with a diameter of 0.3 μm or greater generated in the powder generation test described below, is not more than 500 particles /. 0028 m3 (0.1 cubic foot) (more preferably 100 particles / .0028 m3 (0.1 cubic foot) or less). Such clean paper may be commercially available, and examples thereof include clean paper manufactured by Fuji Paper Co. , Ltd. under the trade name of "OK Clean White", a non-woven fabric of spunbond filaments, manufactured by TORAY Industries, Inc. under the tradename "Axtar G2260-1S", and a non-woven fiber fabric discontinuous wet aramid beads manufactured by OJI PAPEL Co., Ltd. under the tradename "KEVLAR Paper".

The thickness of the surface material is not particularly limited, but is preferably from about 0.01 to 2 mm, more preferably from about 0.01 to 1 mm, even more preferably from about 0.01 to 0.5 mm, most preferably about 0.03 to 0.1 mm. The mass of the surface material per unit area is preferably as light as possible, but is from about 10 to 400 g / m2, preferably about 20 to 400 g / m2, more preferably about 20 to 100 g / m2, from the point of resistance view. In the present invention, the non-woven fabric can take various forms such as polyhedron (e.g., hexahedrons such as a rectangular parallelepiped) and column and cylinder. In a case where the non-woven fabric of the sound absorbing material according to the present invention is a polyhedron, the surface material can be laid in layers on one of the sides of the polyhedron (eg, a rectangular parallelepiped) or the surface material It can be laid in layers on two or more of the faces of the polyhedron. In a case where the non-woven fabric is in the form of a column or a cylinder, the surface material is preferably laid in layers on a curved face of the column or cylinder. The surface material and the non-woven fabric can they are layered together in a state where they are not joined to one another, but are preferably lying in layers together in a state where they are joined to each other by a conventional method of joining. As a joining method, bonding using resin rivets (for example, "Bano'k" manufactured by Japan Bano'k), fusion, suture, needle piercing, bonding using adhesives, thermal etching, ultrasonic bonding, sintering bonding using adhesive resins, or bonding with a soldering iron, can be mentioned. In addition to these methods, a joining method can also be used in which a low melting point material such as a low melting point network, a low melting point film or a low melting point fiber provided between the surface material and the unbonded fabric is melted by heat treatment to bond the surface material and the non-woven fabric together by means of the low melting point material. Here, the melting point of the low melting point material is preferably lower than that of another fiber used for the nonwoven fabric or the surface material, by 20 ° C or more. It is noted that in a case where a sintering joint is employed as the joining method, an adhesive resin powder (e.g., nylon 6, nylon 66, polyester) or a low temperature adhesive resin powder (for example) is preferably used. example, EVA (low melting point ethylene copolymer-vinyl acetate)). In the case of bonding using adhesives, either thermoplastic adhesives or thermosetting adhesives can be used. In this case, for example, after an epoxy thermosetting resin is applied on the surface material or the non-woven fabric, the surface material and the non-woven fabric are layered together, and are then subjected to heat treatment for cure the resin. A greater degree of bond between the surface material and the non-woven fabric (a greater number of bonding points or a larger surface area for bonding) allows the surface material and the non-woven fabric to be more firmly bonded together, but the The degree of union between these is too high, the sound absorption coefficient of a resulting sound absorbing material is diminished. In a case where there is no bond between the surface material and the nonwoven fabric, the sound absorption coefficient of a resulting sound absorbing material is increased, but problems such as detachment in use and poor handling occur. From such a point of view, the number of attachment points between the surface material and the non-woven fabric is at least 1 point / cm 2 but preferably no more than 30 points / cm 2, more preferably no more than 20 points / cm 2, yet plus preferably not greater than 10 points / cm2. The surface area of the joining point (s) is preferably as small as possible, because if the surface area of the joining point (s) is too large, the sound absorption coefficient of a resulting sound absorbing material decreases. . For example, when the total surface area of the joint points is defined as "B" and the total surface area of the joint points and non-union points is defined as "A + B", the ratio of the total surface area of the points of union (B) to the total surface area of the junction points and non-union points (A + B), that is, the proportion represented by the formula:. { B / (A + B)} X 100 (%) is preferably not greater than 30%, more preferably not greater than 20%, even more preferably not greater than 10%. In order to decrease the number of bonding points or the bonding ratio, a low melting point material formed within a network form or a small amount of particles of the low melting point material, which has a size of relatively large particle, it is preferably used as an adhesive. In the sound absorbing material according to the present invention, the surface material needs to be laid in layers on at least one of the sides of the non-woven fabric, but it can be laid in layers on both sides of the nonwoven fabric. In addition, the sound absorbing material according to the present invention may have a multilayer structure in which at least one or more layers of the non-woven fabric, and at least one or more layers of the surface material are laid in layers and unified among themselves. In this case, the number of layers is not particularly limited. The sound absorbing material according to the present invention can be colored with dyes or pigments if necessary. In a case where a colored sound absorbing material is manufactured, a yarn dyed by spinning, obtained by spinning a polymer mixed with a dye or pigment, or colored fibers by various methods can be used. Alternatively, the sound absorbing material itself can be colored with dyes or pigments. If necessary, the sound absorbing material according to the present invention can be coated or impregnated with an acrylic resin emulsion, or an acrylic resin emulsion or an acrylic resin solution containing a well-known fire retardant, such as a phosphate-based fire retardant, a halogen-based fire retardant, or a hydrated metal compound for purposes of further improving fire retardancy or abrasion resistance thereof.

The sound absorbing material according to the present invention can be used for various applications by forming it to have a desired size or shape by, for example, a well-known method according to its purpose of use or application. The sound absorbing material according to the present invention can be used for all applications that require fire retardancy and sound absorbency. For example, the sound absorbing material according to the present invention is suitably used for interior materials of transportation facilities such as vehicles (e.g., automobiles and freight cars), boats and boats, and airplanes, and civil engineering materials. / construction (for example, wall materials and roofing materials). Particularly, the use of the sound absorbing material according to the present invention as the interior material of a vehicle engine space, makes it possible to prevent the dispersion of the fire in the event of a fire outbreak in the engine space. , and to prevent the engine space noise from escaping out of the engine space. In addition, the sound absorbing material according to the present invention can also be used for various applications such as roofing materials for vehicles, flooring materials, rear packs, and door frames; insulators boards of automobiles, trains and airplanes; electrical products such as electric vacuum cleaners, exhaust fans, electric washing machines, electric refrigerators, freezers, electric clothes dryers, electric mixers, electric juicers, air conditioners, hair dryers, electric razors, air cleaners, electric dehumidifiers , and electric lawn mowers; diaphragms for speakers; and machinery for civil engineering / construction such as circuit breakers (for example, case covers). The sound absorbing material according to the present invention obtained by the use of clean paper as the surface material, especially the sound absorbing material comprising clean paper as the surface material and the non-woven fabric in which a discontinuous fiber is interlaced Polyester with a discontinuous aramid fiber, it is preferably used as a sound absorbing material for mechanical equipment and air conditioning equipment in clean rooms and for buildings for clean rooms. It is preferred that the back surface of the sound absorbing material according to the present invention (i.e., the surface of the sound absorbing material on the side of the non-woven fabric) or the surface side thereof is coupled to a member such as a reflector or a fixing plate when the sound absorbing material is used. Examples of the "member" material include metals such as aluminum, resins such as rubber and wood. The shape of the "member" is not particularly limited, and the "member" may have either a form of structure or a case form In the present invention, the "member" is preferably a reflector. The reflector Examples of the reflector include metal plates and resin plates As a metal plate, a well-known metal plate can be used, as long as it is made of a metallic material and is formed to have a plate shape, and The type of metal and the size of the metal plate are not particularly limited Examples of such plate include metal plates made of stainless steel, iron, titanium, nickel, aluminum, copper, cobalt, iridium, ruthenium, molybdenum, manganese and alloys which contain two or more of them, and compounds made of such metals and carbon, and formed to have a plate shape.As a resin plate, a well-known resin plate can be used as long as it is made of a resin that is formed to have a plate shape, and the type of resin and the size, the mechanical properties and the additives of the plate Resin are not particularly limited. Examples of such a resin plate include synthetic resin plates, fiber reinforced resin plates, and rubber plates. The synthetic resin plate is manufactured by forming a synthetic resin in a plate form according to a well known formation method. Examples of the synthetic resin include thermoplastic resins and thermosetting resins. Examples of the thermoplastic resins include polyester resins such as polyethylene terephthalate (PET) resins, polybutylene terephthalate resins (PBT), polytrimethylene terephthalate (PTT) resins, polyethylene naphthalate (PEN) resins, and liquid crystal polyester resins, polyolefin resins such as polyethylene (PE) resins, polypropylene resins (PP), and polybutylene resins; styrene-based resins, polyoxymethylene resins (POM), polyamide resins (PA), polycarbonate resins (PC), polymethyl methacrylate resins (PMMA), polyvinyl chloride (PVC) resins, polyphenylene sulfide resins (PPS) ), polyphenylene ether (PPE) resins, polyphenylene oxide (PPO) resins, polyimide (PI) resins, polyamide-imide resins (PAI), polyether-imide resins (PEI) polysulfone resins (PSU) , polyethersulfone resins, polyketone resins (PK) polyether ketone resins (PEK), polyether ether resins ketone (PEEK), polyarylate resins (PAR), polyetheritrile resins (PEN), phenol resins (for example, novolac-phenol resin plates), phenoxy resins and fluoride resins, thermoplastic elastomers based on polystyrene, based on polyolefin, based on polyurethane, based on polyester, based on polyamide, based on polybutadiene, based on polyisoprene, and based on fluorine, and copolymer resins and modified resins thereof. Examples of thermosetting resins include phenol resins, epoxy resins, epoxy acrylate reams, polyester resins (e.g. unsaturated polyester resins), polyurethane resins, resins, diallyl phthalate resins, silicone resins, ester resins vinyl, melamine resins, polyimide resins, polybismaleimide-triazine resins (BT), cyanate resins (eg, cyanate ester resins), copolymer resins thereof, denatured resins thereof, and mixtures thereof . The fiber reinforced resin plate is not particularly limited, as long as it is composed of a fiber and a resin (for example, the aforementioned thermosetting resin) and is thus formed to have a plate form. As such a fiber reinforced resin plate, a well-known fiber reinforced resin plate can be used. In general, such fiber-reinforced resin plate is manufactured according to a well-known method, i.e., by impregnating a fiber or a fiber product with a prepreg (ie, with an uncured thermosetting resin) and then curing it by heating. The fiber that is going to be used as a raw material can be either a discontinuous fiber or a filament. In any case, the fiber material is generally manufactured using a synthetic resin mentioned above, according to a well-known method. Examples of the fiber product include yarns, braids, woven fabrics, knitted fabrics, and non-woven fabrics. These fiber products are generally manufactured using the aforementioned fibers according to a well-known method. Preferred examples of the fiber reinforced resin plate include fiber reinforced resin plates, composed of a carbon fiber and an epoxy resin (epoxy resin plates reinforced with carbon fiber). Examples of the rubber plate include natural rubber plates and synthetic rubber plates. The resin plate described above can be an electromagnetic wave absorption plate. As a plate for absorbing electromagnetic waves, a well-known electromagnetic wave absorption plate, such as a "material", can be mentioned by way of example. of electromagnetic wave shielding formed in a plate shape "described in Japanese Patent Application Laid-Open No. 2003-152389.In a preferred case where the sound absorbing material according to the present invention is coupled to the member when uses, for example, an aluminum plate is coupled to the back surface of the sound absorbing material, and an aluminum structural member is coupled to the entire periphery of the sound absorbing material to obtain a sound absorption panel. , such sound absorption panel can be placed, for example, inside the case of the mechanical equipment that generates noise, or it can be used as a division.

E j emplos Hereinafter, the present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to the Examples only. It should be noted that the characteristic values in the Examples and Comparative Examples were obtained according to the following methods.

Air Permeability The air permeability of the surface material was measured by a fragile method according to JIS L-1096.

Sound Absorption Coefficient The normal incidence sound absorption coefficients of the sound absorbing material were measured at various frequencies using an automatic meter (manufactured by SOTEC Co., Ltd.) for the normal incidence sound absorption coefficient by a "test method for The sound absorption of normal incidence of building materials by the pipe method "according to JISA 1405. The measurement was carried out in such a way that the sound absorbing material was placed in the meter so that the surface material it was directed towards a sound source.

Thickness The thickness of each of the surface material and the non-woven fabric was measured under a load of 0.1 g / cm2 using a compression hardness tester (manufactured by Daiei Kagaku Seiki MFG Co., Ltd.).

Shrinkage due to Dry Heat at 280 ° C The length of a fiber was measured before and after the fiber was heated to 280 ° C for 30 minutes in the air, and the shrinkage of the fiber was determined based on the length of the fiber measured before heating.

Degree of Dust Generation The dust generation degree of the surface material was measured by a rotary method according to JIS B 9923. First, a rotating drum-type powder-generating tester in a clean room was started in vacuum to verify that no dust existed in the room. the tester Then, the surface material (20 cm x 28.5 cm) that was not subjected to cleaning wash was placed in the rotating drum-type powder generation tester (CW-HDT101), and the tester was operated at a drum rotation speed of 46 rpm. After the lapse of 1 minute from the start of the operation, the number of dust particles was measured at a speed of .0028 m3 (0.1 cubic foot) / minute every minute. The measurement of the number of dust particles per minute was continuously carried out 10 times, and an average value per minute was defined as the number of dust particles generated. As an accountant of dust is used 82-3200N, and the maximum volume of suction air at the time when a filter was used, was 2.2 liters / minute. Five samples, each having a size of 20 cm x 28.5 cm, were used. The number of dust particles generated was expressed in terms of the number of dust particles generated in a 1 cm x 1 cm sample. As shown in Table 1, the degree of dust generation was evaluated according to a rating criterion of 5 in terms of the total number of dust particles with a diameter of 0.3 μm or greater. A paper with a grade of 4 or 5 was defined as clean paper.

Table 1 Example 1 A discontinuous para-aramid fiber manufactured by DU PONT TORAY Co. , Ltd., under the tradename "KEVLARR" (1.7 dtex x 51 mm, shrinkage by dry heat at 280 ° C: 0.1% or less, LOI value: 29) and a discontinuous fiber of polyethylene terephthalate (PET) ( 1.7 dtex x 51 mm) manufactured by TORAY Industries, Inc. were mixed in a mass ratio of 30:70 to prepare a non-woven PET / aramid fabric having a thickness of 10 mm and a mass per unit area of 400 g / m2 by drilling with water. The apparent density of the nonwoven fabric obtained was 0.04 g / cm3 At the same time, a 3 mm staple fiber yarn of a para-aramid fiber having a single yarn fineness of 1.7 dtex ("KEVLAR®", manufactured by DU PONT-TORAY Co., Ltd.) and meta-aramid fiber ("Nomex" ", manufactured by USA DU PONT) as pulp were mixed in a mass ratio of 90:10, and then subjected to a papermaking process and calendered to obtain an aramid paper having a thickness of 95 μm, a mass per unit of air at 71 g / m2, and an air permeability of 0.81 ce / cm2 / second as a material superficial. surface material, 75 g / m2 of an ethylene-vinyl acetate copolymer powder (EVA) of low melting point (melting point: 80 ° C) was sprayed, and then the PET / aramid non-woven fabric perforated by needle , was placed in layer on the surface material. The surface material and the non-woven fabric were sandwiched between gauzes of metallic wire mesh, and then subjected to heat treatment at 160 ° C for 3 minutes to join them together, whereby a sound absorbing material was obtained. "paper (PET / aramid non-woven fabric) / aramid".

Example 2 A polyethylene terephthalate (PET) non-woven fabric having a thickness of 10 mm, a mass per unit of air of 400 g / m 2, and a bulk density of 0.04 g / cm 3 was prepared by needle punching using a discontinuous fiber of polyethylene terephthalate (PET) (1.7 dtex x 51 mm) manufactured by TORAY Industries, Inc. On the other hand, a non-woven fabric of polyethylene terephthalate (PET) joined by spinning ("Axtar® G2260", manufactured by TORAY Industries, Inc.) having a thickness of 560 μm, a mass per unit area of 260 g / m2, and an air permeability of 11.5 cc / cm2 / second was prepared as a surface material. In the same manner as in Example 1, the surface material was attached to the non-woven PET fabric perforated with needle, to obtain a sound absorbing material of "PET non-woven fabric perforated with needle / non-woven PET fabric joined by spinning".

Example 3 A non-woven aramid fabric having a thickness of 10 mm, a mass per unit of air of 400 g / m2, and a bulk density of 0.04 g / mc3 was obtained by perforating with a needle using only the same discontinuous fiber of -aramid ("KEVLAR®") which is used in Example 1. As a surface material, the same aramid paper that was used in Example 1 was prepared. In the same manner as in Example 1, the aramid paper as a surface material and the non-woven aramid fabric were bonded together to obtain a "non-woven aramid / aramid paper" sound absorbing material.

Comparative Example 1 A sound absorbing material was obtained in the same manner as in Example 1, except that the Aramid paper was omitted. That is, only one non-woven fabric containing a discontinuous fiber of KEVLAR and a discontinuous fiber of polyethylene terephthalate (PET) in a mass ratio of 30:70 was prepared.

Comparative Example 2 A commercially available blown nonwoven fabric was prepared in molten form ("Thinsulfat e", manufactured by Sumitomo 3M Ltd.) in which polypropylene (PP) and polyethylene terephthalate (PET) are mixed in a mass ratio of 65:35. The nonwoven fabric blown in molten form had a thickness of 10 mm and a mass per unit area of 240 g / m2. The properties of each of the sound absorbing materials and the relationship between the frequency and the sound absorption coefficient are shown in Table 2. As is clear from Table 2, all the sound absorbing materials of the Examples 1 to 3 are superior in sound absorbency to those of the Comparative Examples.

Table 2 Example 4 A discontinuous polyethylene terephthalate (PET) fiber (1.7 dtex x 44 mm) manufactured by TORAY Industries, Inc., a discontinuous fiber of polyethylene terephthalate (PET) (6.6 dtex x 51 mm) manufactured by TORAY Industries, Inc., and a low melting point yarn manufactured by TORAY Industries, Inc., under the trade name of "SAFMET" ( melting point: 110 ° C, 4.4 dtex x 51 mm) were mixed in a mass ratio of 60:20:20 and then subjected to a carding step to obtain a network. Then, the network was perforated with a needle to obtain a non-woven net. The nonwoven web was subjected to heat treatment at 150 ° C for 3 minutes to melt the low melting point yarn so that the other discontinuous polyester fibers were partially bonded together, thereby obtaining a non-woven fabric. which has a thickness of 10 mm, a mass per unit area of 400 g / m2 and an apparent density of 0.04 g / cm3. On the nonwoven fabric obtained in this way, 10 g / m2 of an EVA powder "2030-M" manufactured by Tokyo Printing Ink MFG was sprayed. Co., Ltd. and then continuously heated at 140 ° C for 1 minute. Then, a clean paper made by Fuji Paper Co. , Ltd. under the trade name "Clean Paper OK clean white" (thickness: 90 μm, weight: 70 g / m2, air permeability: 0.15 cc / cm2 / second) was layered on a surface material on the cloth non-woven, and then these were joined together by pressing using a cooling roller to obtain a sound-absorbing material. The dust generation properties of clean paper Used as a surface material, they are shown right away. The dust generation level of clean paper is given with a rating of 5.

Table 3 Example 5 The same non-woven fabric used in Example 1 and a non-woven fabric of spin-bonded polyethylene terephthalate (PET) filaments manufactured by TORAY Co. , Ltd. under the trade name of "Axtar G2260-1S" (thickness: 620 μm, weight: 260 g / m2, air permeability: 11 cc / cm2 / second) as a surface material were joined together in the same way than in Example 1, to obtain a sound absorbing material. The dust generation properties of the surface material are shown below. The degree of dust generation of the surface material was given a rating of 4.

Table 4 Example 6 The same nonwoven fabric that was used in Example 1 and 100% KEVLAR® manufactured by OJI PAPER Co., Ltd. (thickness: 95 μm, weight: 72 g / m2, air permeability: 0.93 cc / cm2 / second) as a surface material were bonded together to obtain a sound absorbing material. The non-woven fabric and the surface material were bonded together using an ON5058 network of NISSEKI Conwed manufactured by NISSEKI PLASTO Co., Ltd. Specifically, the Conwed net was placed on the non-woven fabric, and then these were heated to 150 ° C. for 1 minute to melt the surface of the Conwed network. Then, the surface material was placed on the Conwed net and these were compressed with a cooling roller to join the surface material and the non-woven fabric together. The non-woven fabric and the surface material were joined by means of the meshes of the Conwed net having a mesh size of 8 mm. The proportion of surface area total of the binding points of the KEVLAR paper and the non-woven fabric via the Conwed network (B) to the total surface area of the junction points and non-union points (A + B), that is, the proportion represented by the formula: { B / (A + B)} x 100 (%) was 2%.

Example 7 The same nonwoven fabric that was used in Example 1 and the same aramid paper that was used in Example 1 as a surface material were bonded together to obtain a sound absorbing material. The non-woven fabric and the surface material were joined together using a double-sided tape. Specifically, the double-sided tape was glued to the surface material, and the non-woven fabric was laid in layers on it. Then, the surface material and the non-woven fabric were compressed using a roller, to bring them into full and firm contact with each other. The ratio of the total surface area of the junction points (B) to the total surface area of the junction points and the non-union points (A + B) was 100%. The absorption coefficients of sound at normal incidence of the sound absorbing materials of Examples 4 to 7 are shown in Table 5.

Table 5 Example 8 In the same manner as in Example 1, the same aramid paper that was used in Example 1 was attached as a surface material to one of the surfaces of the same nonwoven fabric that was used in Example 1 to obtain a sample . In addition, the same surface material that was used in Example 1 (ie, aramid paper) was laid in layers on the surface of the non-woven fabric of the sample, ie, on the surface opposite the surface of the surface material of the sample, and then these were joined together by heating in the same manner as in Example 1, whereby a sound absorbing material of "aramid paper / (PET / non-woven aramid fabric) / paper is obtained of aramid. " Sound Transmission Loss Test The sound transmission losses of the sound absorbing materials obtained in the Examples 1 and 8 were measured according to JIS A 1416.

The results of the measurement are shown in Table 6.

Table 6 Example 9 As a surface material, the KEVLAR paper containing mica (manufactured by Du Pont Teijin Advanced Papers) was prepared (thickness: 75 μm, weight: 86 g / m2, air permeability: 0 cc / cm2 / second) manufactured by manufacturing paper using a mixture of a 5 mm discontinuous fiber yarn of para-aramid fiber ("KEVLAR®" manufactured from DuPont Teijin Advanced Papers, Ltd.) having a single yarn fineness of 1.7 dtex and mica as a mineral silicate. The surface material was bonded to the same non-woven fabric that was used in Example 1, in which the discontinuous KEVLAR® fiber and a discontinuous polyethylene terephthalate (PET) fiber were mixed in a mass ratio of 30:70. (thickness: 10 mm, weight: 400 g / m2), in the same manner as in Example 1 using a powder of low melting point, whereby a sound absorbing material is obtained with KEVLAR paper containing mica.The sound absorption coefficients at normal incidence of this sound absorbing material were measured, and the results of the measurement are shown in Table 7. The flame resistance test was performed on the sound absorbing material according to the vertical burn test UL-94. A gas burner having a nozzle with an outer diameter of 19 mm and an internal diameter of 16.5 mm was used, and the length of the gas flame was adjusted to 140 mm.The sound absorbing material was kept in the gas flame at the position of a flame length of 100 mm for 4 minutes, in a manner such that the sound absorbing material was perpendicular to the flame (at this time, the surface material was placed on the same side of the flame) to verify if an orifice was produced in the surface material and in the fabric n or woven. As a result, no hole was observed in the surface material and in the non-woven fabric layers of the sound absorbing material.

Example 10 A discontinuous fiber of polyethylene terephthalate (PET) (1.7 dtex x 44 mm) manufactured by TORAY Industries, Inc., a discontinuous polyethylene terephthalate fiber (6.6 dtex x 51 mm) manufactured by TORAY Industries, Inc., and a low melting point yarn manufactured by TORAY Industries, Inc., under the trade name "SAFMET" "(melting point: 110 ° C, 4.4 dtex x 51 mm) were mixed in a mass ratio of 60:20:20, and then punched with a needle to prepare a non-woven fabric having a thickness of 10 mm, a mass per unit area of 200 g / m2, and an apparent density of 0.02 g / cm3. As a surface material, "100% polyester paper" (thickness: 90 μm, weight: 54 g / m2, air permeability: 0.9 cc / cm2 / second) manufactured by OJI PAPER Co., Ltd., and the Surface material was bonded to the non-woven fabric in the same manner as in Example 1, using a low melting point EVA powder to obtain a sound absorbing material of "non-woven fabric of polyethylene terephthalate (PET) / paper Of polyester" . The normal incidence sound absorption coefficients of this sound absorbing material were measured, and the results of the measurement are shown in Table 7.

Example 11 A discontinuous fiber of polyethylene terephthalate (PET) (1.7 dtex x 44 mm) manufactured by TORAY Industries, Inc., a discontinuous polyethylene terephthalate (PET) fiber (6.6 dtex x 51 mm) manufactured by TORAY Industries, Inc., and a low melting point yarn manufactured by TORAY Industries, Inc., under the tradename " SAFMET "(melting point: 110 ° C, 4.4 dtex x 51 mm) were mixed in a mass ratio of 60:20:20, and then subjected to a carding step to obtain a network. The net was perforated by a needle to obtain a non-woven fabric. The non-woven fabric was heated at 150 ° C for 3 minutes to melt the low melting yarn, so that other discontinuous polyester fibers were partially bonded together, thereby obtaining a non-woven fabric of polyethylene terephthalate (PET) having a thickness of 10 mm, a mass per unit area of 200 g / m2, and an apparent density of 0.02 g / cm3. At the same time, a discontinuous fiber yarn (1.7 dtex x 5 mm) of a para-aramid fiber ("KEVLAR®", manufactured by DU PONT-TORAY Co., Ltd.) and meta-aramid fiber ("Nomex") "", manufactured by US DU PONT) as pulp, were mixed in a mass ratio of 95: 5, and then subjected to a papermaking process and calendered to obtain an aramid paper having a thickness of 70 μm, a mass per unit area of 36 g / m2, and an air permeability of 20.5 cc / cm2 / second as a surface material.The surface material and the non-woven fabric were bonded together in the same way as at Example 1, to obtain a sound absorbing material. Two sheets of the sound absorbing material obtained in this way were laid together in a layer, and the aramid paper composed of KEVLAR® and Nomex® used in Example 1 (thickness: 95 μm, weight: 71 g / m2, air permeability : 0.81 cc / cm2 / second) was subsequently placed at the bottom to measure the sound absorption coefficients of normal incidence of them. The results of the measurement are shown in Table 7.

Table 7 Comparative Example 3 A non-woven fabric of polyethylene terephthalate (PET) at 100% having a thickness of 2.5 mm, a mass per unit area of 100 g / cm2, and an apparent density of 0.025 g / cm3 was obtained using the same fibers as used in Example 4, a the same mixing ratio as in Example 4, and in the same manner as in Example 4. The same surface material (i.e., aramid paper) that was used in Example 1, was attached to the non-woven fabric of same as in Example 1, to obtain a sound absorbing material.

Comparative Example 4 A non-woven fabric of 100% polyethylene terephthalate (PET) having a thickness of 5 mm, a mass per unit area of 45 g / cm 2, and an apparent density of 0.009 g / cm 3 was obtained using the same fibers as used in Example 4, at the same mixing ratio as in Example 4, and in the same manner as in Example 4. The same surface material (ie, aramid paper) as used in Example 1 was bonded to the non-woven fabric in the same manner as in Example 1 to obtain an absorbing material. Sound .

Comparative Example 5 A nonwoven fabric of 100% polyethylene terephthalate (PET) having a thickness of 25 mm, a mass per unit area of 900 g / cm2, and an apparent density of 0.036 g / cm3 was obtained using the same fibers as were used in Example 4, at the same mixing ratio as in Example 4, and in the same manner as in Example 4. The same surface material (ie, aramid paper) as used in Example 1, was attached to the non-woven fabric in the same manner as in Example 1 to obtain a sound absorbing material. Comparative Example 6 A wet-laid nonwoven fabric of 100% aramid fiber having a thickness of 5.5 mm, a mass per unit area of 1582 g / m2, and an apparent density of 0.29 g / cm3 was obtained by papermaking using the "KEVLAR®" pulp made by the USA DU PONT. The same surface material that was used in Example 1 was attached to the nonwoven fabric in the same manner as in Example 1, to obtain a sound absorbing material.

Comparative Example 7 A non-woven fabric of 100% polyethylene terephthalate (PET) having a thickness of 10 mm, a mass per unit area of 200 g / cm2, and an apparent density of 0.02 g / cm3 was obtained using the same fibers as in Example 4, at the same mixing ratio as in Example 4, and in the same manner as in Example 4. A surface material of 100% polyethylene terephthalate (PET) that had a thickness of 410 μm, a mass per unit area of 59 g / m2, and an air permeability of 93 cc / cm2 / second was obtained using the same fibers that were used for the non-woven fabric of the Example 4, in the same mixing ratio as in Example 4, in the usual manner, that is, by mixing and needle piercing the fibers. The thus obtained nonwoven fabric and the surface material were joined together in the same manner as in Example 1, using a low melting point powder to obtain a sound absorbing material. The sound absorption coefficients at normal incidence of the sound absorbing materials obtained in Comparative Examples 3 to 7 are shown in Table 8.

Table 8 As is clear from Tables 7 and 8, the The sound absorbing material of Example 11 had a higher sound absorption effect of relatively low frequency (i.e. sound of 1000 Hz or less, especially 500 Hz or less) compared to other sound absorbing materials because the thickness of the sound absorbing material of Example 11 was larger due to its layered structure. In addition, the sound absorbing material whose non-woven fabric had a relatively light weight (Example Comparative 3) had lower sound absorption coefficients at low and high frequencies. On the other hand, the sound absorbing material whose non-woven fabric had a relatively heavy weight (Comparative Example 5) had a high effect of sound absorption due to an increased thickness, but its heavy weight caused problems in handling capacity and working capacity. The sound absorbing material whose non-woven fabric had a relatively low bulk density (Comparative Example 4), had low sound absorption coefficients, and such a sound absorbing material probably collapsed due to the application of charges. The sound absorbing material whose non-woven fabric had a relatively high bulk density (Comparative Example 6) was poor in handling capacity because it was too stiff and heavy. In addition, the sound absorbing material whose surface material had an air permeability exceeding 50 cc / cm2 / second (i.e., the sound absorbing material of Comparative Example 7) did not have an improved sound absorbency even if the surface material was joined to the non-woven fabric, because the air permeability of the surface material was too large.

Possibility of Industrial Application The sound absorbing material according to the present invention is useful as an absorbing material of sound that will be used in the fields of electrical products such as air conditioners, electric refrigerators, electric washing machines, audiovisual equipment, and electric lawn mowers; transportation facilities such as vehicles, boats and boats, and airplanes; and construction materials such as building wall materials.

It is noted that in relation to this date, the best known method for carrying out the aforementioned invention is that which is clear from the present description of the invention

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A sound-absorbing material, characterized in that a non-woven fabric with a mass per unit area of 150 to 800 g / m 2 and a bulk density of 0.01 to 0.2 g / cm 3, and a surface material with a permeability to the fabric are layered. air no greater than 50 cc / cm2 / second measured according to JIS L-1096.

2. The sound absorbing material according to claim 1, characterized in that the non-woven fabric is a fabric in which a thermoplastic discontinuous fiber and a heat-resistant discontinuous fiber with a LOI value of not less than 25 are interlaced.

3. The sound absorbing material according to claim 2, characterized in that the weight ratio of the thermoplastic discontinuous fiber and the heat resistant discontinuous fiber is in a range of 95: 5 to 55:45.

4. The sound absorbing material according to claim 2, characterized in that the weight ratio of the discontinuous thermoplastic fiber and the Heat-resistant discontinuous fiber is in a range of 85:15 to 55:45.

The sound absorbing material according to any of claims 2 to 4, characterized in that the thermoplastic discontinuous fiber is at least one type of discontinuous fibers selected from the group consisting of a polyester fiber, a polypropylene fiber and a nylon fiber.

The sound absorbing material according to any of claims 2 to 5, characterized in that the thermoplastic discontinuous fiber is at least one type of discontinuous fibers selected from the group consisting of an aramid fiber, a sulfide fiber of polyphenylene, a polybenzoxazole fiber, a polybenzothiazole fiber, a polybenzimidazole fiber, a polyether ether ketone fiber, a polyarylate fiber, a polyimide fiber, a fluoride fiber, and a fire resistant fiber.

The sound-absorbing material according to any of claims 2 to 4, characterized in that the thermoplastic discontinuous fiber is a discontinuous polyester fiber and the heat-resistant discontinuous fiber is a discontinuous aramid fiber.

8. The sound absorbing material according to any of claims 1 to 7, characterized in that the non-woven fabric is produced by the water-borne method or the water-jet method.

9. The sound absorbing material according to any of claims 1 to 8, characterized in that the surface material is a spunbonded non-woven fabric or a shredded non-woven wet shredded fabric.

10. The sound-absorbing material according to claim 9, characterized in that the non-woven fabric laid wet is comprised of a heat-resistant discontinuous fiber with a LOI value of not less than 25.

11. The sound-absorbing material of according to claim 9, characterized in that the wet-laid non-woven fabric is comprised of a heat-resistant discontinuous fiber with a LOI value of not less than 25 and a silicate mineral.

12. The sound absorbing material according to claim 11, characterized in that the silicate mineral is mica.

13. The sound absorbing material according to claim 10 or 11, characterized in that the heat-resistant batch fiber is a discontinuous aramid fiber.

14. The sound absorbing material according to any of claims 9 to 13, characterized in that the surface material has a dust generation number no greater than 500 particles / .0028 m3 (0.1 cubic foot) of particles with a diameter not less than 0.3 μm, measured by the rotating drum method according to JIS B-9923 6.2 (1.2).

15. The sound absorbing material according to any of claims 1 to 14, characterized in that the nonwoven fabric and the surface material are comprised of the same type of synthetic fiber.

16. The sound absorbing material according to any of claims 1 to 15, characterized in that the non-woven fabric and the surface material are laid in layers by joining, and the number of the points of attachment of the non-woven fabric and the surface material is not greater than 30 points / cm2, and the ratio of the total surface area of the points of attachment to the total surface area of the junction points and non-union points is not greater than 30%.

The sound absorbing material according to any of claims 1 to 16, characterized in that the non-woven fabric is in the shape of a polyhedron and the surface material is placed in layers on two or more sides of the polyhedron.

18. The sound absorbing material according to claim 17, characterized in that the non-woven fabric is in the form of a hexahedron and the surface material is laid in layers on both side faces of the hexahedron.

19. The sound absorbing material according to any of claims 1 to 16, characterized in that the non-woven fabric is in the form of a column or a cylinder, and the surface material is placed in layers on the curved face of the column or the cylinder.

20. The sound absorbing material according to any of claims 1 to 16, characterized in that it has a multilayer structure comprising at least one or more layers of each of the non-woven fabric and the surface layer, wherein both layers are joined.

21. The sound absorbing material according to any of claims 1 to 19, characterized in that it is used as a vehicle interior material or a vehicle exterior material.

22. The sound absorbing material according to any of claims 1 to 19, characterized in that it is used as a sound absorbing material for a lawn mower.

23. The sound absorbing material according to any of claims 1 to 19, characterized in that it is used as a sound absorbing material for a breaker or circuit breaker.