RU2358246C2 - Sound adsorbing material - Google Patents

Abstract

FIELD: textile, paper.

SUBSTANCE: sound adsorbing material comprises layered non-woven fabric with weight per area unit equal to 150-800 g/m² and volume density equal to 0.01-0.2 g/cm² and surface material with air permeability not more than 50 cm³/cm²/s measured according to JIS L-1096 standard. The non-woven fabric and surface material are arranged in layers by binding, amount of binding points for the non-woven fabric and surface material amounts to 30 points/cm² at most, and the relation of the total binding point square to the total binding point square and points without binding amounts to 30% at most.

EFFECT: improving material sound adsorbing properties.

22 cl

Description

The present invention relates to sound-absorbing material, in particular to sound-absorbing material intended for use, for example, in areas related to electrical equipment such as air conditioning units, electric refrigerators, electric washing machines and electric lawn mowers; with transport equipment, such as vehicles, boats and ships, aircraft; or with building materials, such as building materials for walls, and in areas related to civil engineering, with construction machines.

Sound-absorbing materials are traditionally used, for example, for electrical equipment, building materials for walls and vehicles. In particular, to prevent the occurrence of external noise during acceleration or external noise during idle from vehicles such as automobiles, specifications are generally accepted that require engines and gearboxes to be surrounded by acoustic shields. Typically, in the case of automobiles, such acoustic screens are necessary not only for good sound absorption, but also to prevent the spread of flame to the driver’s seat when the flame breaks into the engine compartment due to a traffic accident, to ensure safety. Thus, from the point of view of flame prevention, there is a need for a flame retardant, sound-absorbing material, with excellent characteristics not only in terms of sound absorption, but also fire safety. In addition, it is also desirable that no toxic gas is formed during the burning of such a flame retardant, sound-absorbing material.

In addition to having sound absorption and flame retardation, it is desirable that sound absorbing materials for vehicles, such as automobiles, are made of lightweight and recyclable materials to reduce the weight of automobiles and encourage the recycling of sound absorbing materials from automobile scrap. Since encouraging the reuse of various parts of automobile scrap to minimize the amount of industrial waste from automobile scrap is considered important to prevent environmental pollution.

For the reasons described above, lightweight and flame retardant nonwoven materials, such as those meeting the requirements described above, are preferred. Typically, flame retardant non-woven materials are produced using non-woven materials as the main constituent of synthetic fibers, for example flame retardant fibers such as aramid fibers and “polychlal” fibers, or using synthetic fibers into which a phosphoric acid based flame retardant or flame retardant based boric acid, or by coating or impregnating sheet nonwoven materials with a binder coating solution in which a flame inhibitor is dispersed.

For example, Japanese Patent Application Publication Nos. 62-43336 and 62-43337 describe vehicle interior decoration material obtained by applying a vinyl chloride emulsion to the surface of a nonwoven fabric obtained by needle-piercing a canvas consisting of 95 wt.% Polyester fiber, polypropylene fibers or mixtures thereof and 5 wt.% artificial fiber, drying it to form a flame retardant coating based on resin, and laminating a fiberglass mat on a resin-coated nonwoven fabric mat yala for joining a fiberglass mat with a nonwoven mat. Such material for the interior decoration of vehicles is excellent for slowing down the spread of flame, but is not very suitable for secondary use, since a nonwoven fabric mat is connected to a fiberglass mat. There is an additional problem associated with the material for the interior decoration of vehicles, which is the possibility of the formation of dioxin when burning material for the interior decoration.

Japanese Patent Application Publication No. 9-59857 further describes a flame retardant non-woven fabric produced by laminating layers of a non-woven canvas from a flame retardant staple fiber on both surfaces of a layer of non-woven canvas from a polyester fiber so that the number of layers of a non-woven canvas from a flame retardant staple fiber is 50 wt. .% or more of the total amount of the resulting non-woven material, and by weaving constituent fibers with each other between adjacent layers and canvas. Japanese Patent Application Laid-Open No. 2002-348766 describes a flame retardant sheet material produced by needle-piercing a canvas obtained by mixing a polyester fiber with a flame retardant artificial fiber or a modified acrylonitrile fiber (which is obtained by copolymerizing acrylonitrile with a vinyl chloride-based monomer and additional inhibit) . Japanese Patent Application Publication No. 2000-328418 describes a halogen-free flame retardant non-woven material produced by bonding a fibrous web containing cellulose-based fiber, polyvinyl alcohol-based fiber and a flame-retardant polyester fiber based on phosphorus-containing compounds with a binder based on acrylic resin. Such non-woven materials described in the aforementioned patent documents have excellent flame retardant performance, but are not suitable for sound absorption.

As an example of a flame retardant sound-absorbing material, Japanese Patent Application Laid-Open No. 2002-287767 describes a sound-absorbing material for vehicles produced by coating and molding a generally sound-absorbing material in the form of a mat in which mineral wool, glass fiber and polyester fiber are randomly oriented in a blended fabric condition, and such fibers are bonded together by a fibrous binder such as a low melting polyester fiber and a surface material that is edit the nonwoven fabric based on polyester fibers, processed to impart moisture resistance, oil resistance and fire resistance. Additionally, Japanese Patent Application Laid-Open No. 2002-161465 describes a sound-absorbing material produced by laminating a flame-retardant non-woven fabric made of polyester yarns as a surface material on one of the surfaces of a layered structure containing melt-woven non-woven fabric and a polyester non-woven fabric connected by needle piercing .

In both of the aforementioned methods, said flame retardant sound-absorbing materials are obtained by joining a sound-absorbing material with a flame-retardant surface material. According to the first of the two methods described above, after the sound-absorbing material in the form of a mat and the surface material covering the sound-absorbing material are completely molded, it is necessary to conduct thermal compression molding at a melting temperature of the fibrous binder or higher, which complicates the method of its production. In the case where the polyester fiber contains a halogen-containing flame inhibitor, there is additionally the possibility of the formation of toxic gas when burning sound-absorbing material. On the other hand, sound-absorbing materials according to the second of the methods have the disadvantage of not sufficiently slowing down the spread of the flame.

From the point of view of the problems described above, the objective of the present invention is to obtain a sound-absorbing material that is effective against sound absorption, has the ability to slow down the spread of flame without the use of a flame inhibitor, does not form droplets of molten liquid when its component melts, has a low ability to shrink and superior properties in terms of reliability, cost-effectiveness and recyclability Ania.

To achieve the aforementioned task, a thorough study was carried out, as a result of which it was found that by layering a surface material with a breathability of not more than 50 cc / cm ² / s, measured according to JIS L-1096 standard, on a non-woven material with a mass per unit area from 150 to 800 g / m ² and bulk density from 0.01 to 0.2 g / cm ³ , in particular of a non-woven material such as material obtained by interweaving the fibers by needle-piercing or bonding with water jets, rather than by thermal melting can be radiate sound-absorbing material, excellent in terms of sound absorption, flame retardation, recyclability and manufacturability. The data obtained led to the completion of the present invention.

In particular, the present invention relates to a sound-absorbing material with a layered structure containing non-woven material with a mass per unit area of from 150 to 800 g / m ² and a bulk density of from 0.01 to 0.2 g / cm ³ and a surface material with breathability no more than 50 cc / cm ² / s, measured according to the JIS L-1096 standard.

In the sound-absorbing material of the present invention, the non-woven material is preferably a material in which a thermoplastic staple fiber and a heat-resistant staple fiber are woven together with a LOI of at least 25. The weight ratio of the thermoplastic staple fiber and the heat-resistant staple fiber is more preferably in the range of 95: 5 to 55:45, and most preferably in the range of 85:15 to 55:45. Sound absorbing material with this structure is a flame retardant sound absorbing material, excellent in terms of slowing down the spread of flame, as well as in terms of sound absorption.

Additionally, in the sound-absorbing material of the present invention, the thermoplastic staple fiber is preferably at least one type of staple fiber selected from the group consisting of polyester fiber, polypropylene fiber and nylon fiber, and the heat-resistant staple fiber is preferably at least one a type of staple fiber selected from the group consisting of aramid fiber, polyphenylene sulfide fiber, polybenzoxazole fiber, polybenzothiazo nogo fibers, polybenzimidazole fibers, polyetheretherketone fibers, polyarylate fibers, polyimide fibers, fluorine fibers and flame retardant fibers. More preferably, the thermoplastic staple fiber is a polyester staple fiber, and the heat-resistant staple fiber is an aramid staple fiber.

In addition, in the sound-absorbing material of the present invention, the surface material is preferably a non-woven material from filament spunbond production method or a non-woven material of a wet laying of staple fiber. Non-woven material and surface material may consist of the same type of synthetic fiber.

In addition, in the sound-absorbing material of the present invention, the surface material is preferably a wet non-woven fabric consisting of a heat-resistant fiber with a LOI index value of at least 25, or a wet non-woven fabric composed of a heat-resistant fiber with a LOI index of not less than 25, and silicate mineral raw materials (e.g., mica). By using such a wet nonwoven fabric as a surface material, a sound-absorbing material with excellent sound absorption and fire resistance properties can be obtained.

In addition, in the sound-absorbing material of the present invention, clean paper is also preferably used as a surface material with dust formation of not more than 500 dust particles per 0.1 ft ³ with a particle diameter of not less than 0.3 μm, measured using a rotary drum processing method according to the standard JIS B-9923 6.2 (1.2). Using such clean paper as a surface material, it is possible to obtain a sound-absorbing material that has excellent characteristics in terms of sound absorption and flame retardation, and has low dust-forming characteristics.

In addition, the nonwoven fabric and the surface material are preferably arranged together in layers in a state where they are bonded together. In this case, the number of bonding points of the nonwoven material 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-bonding points is preferably not more than 30%.

In addition, in the sound-absorbing material of the present invention, the non-woven material may be in the form of a polyhedron or column, or a cylinder with a curved surface. In the first case, the surface material can be layered on two or more faces of the polyhedron. In the second case, the surface material can be layered on the curved surface of the column or cylinder. For example, mention may be made of a sound-absorbing material in which surface material is layered on both surfaces of a hexagonal non-woven material (for example, a rectangular parallelepiped non-woven material). Sound-absorbing material with such a structure is more perfect in terms of sound transmission loss, whereby sound insulation and sound absorption are improved.

In addition, in the present invention, the sound-absorbing material may have a multilayer structure comprising one or more layers of non-woven material and one or more layers of surface material in which the layers are connected to each other. Sound absorbing material with such a structure is more advanced in terms of sound absorption at low frequencies.

The sound-absorbing material described above can be suitably used as sound-absorbing material for interior and exterior decoration of vehicles, lawn mowers and crushers.

According to the present invention, it is possible to obtain a sound absorbing material with excellent sound absorption characteristics (e.g., sound absorption coefficients at normal incidence, sound absorption coefficients in a reverberation chamber), flame retardation, recyclability and processability at low cost. In addition, the use of non-woven material obtained by weaving a thermoplastic staple fiber with a heat-resistant staple fiber makes it possible to provide a highly reliable sound-absorbing material that does not form droplets of molten liquid when its constituent fibers melt, has low shrinkability and does not form toxic gas when burning.

The sound-absorbing material according to the present invention has a layered structure containing a non-woven material 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 breathability of not more than 50 cubic meters .cm / cm ² / s, measured according to JIS L-1096.

Non-woven material intended for use in the present invention may be either a non-woven material of staple fiber or a non-woven material of threads, provided that it has a mass per unit area of from 150 to 800 g / m ² and bulk density of 0, 01 to 0.2 g / cm ³ . Examples of such nonwovens include needle-punched nonwovens, nonwovens bonded with water jets, meltblown nonwovens, spunbond nonwovens, and knit-pierced nonwovens. Of these, needle-punched non-woven materials and non-woven materials bonded with water jets are preferably used, and in particular, needle-punched non-woven materials are preferably used. Untreated felt can also be used as non-woven material.

In the present invention, the cross-sectional shape constituting the nonwoven fiber material is not particularly limited, and the constituent fiber may either have a perfectly circular cross-sectional shape or a modified cross-sectional shape. Examples of a modified cross-sectional shape include an oval, cavity, X, Y, T, L, star, leaf-shaped (e.g., trefoil, quatrefoil, quatrefoil) and other polygonal (e.g., triangular, quadrangular, pentagonal, hexagonal) shapes.

In addition, in the present invention, the non-woven material fiber is a natural fiber or synthetic fiber, however, from the viewpoint of durability, synthetic fiber is preferably used. Examples of synthetic fibers include thermoplastic fibers such as polyester fiber, polyamide fiber (e.g. nylon fiber), acrylic fiber, and polyolefin fiber (e.g. polypropylene fiber, polyethylene fiber). Such fibers can be produced from their starting materials according to a known method, such as wet spinning, dry spinning or melt spinning. Of these synthetic fibers, polyester fiber, polypropylene fiber and nylon fiber are preferably used because of their excellent characteristics in terms of durability and wear resistance. In particular, polyester fiber is most preferably used because of its starting material, that is, by thermally melting the polyester non-woven materials used, a polyester can be obtained, and the polyester thus obtained can be easily recycled, and therefore, the polyester fiber can be produced economically points of view. In addition, non-woven materials made from polyester fiber have good texture and formability. Such thermoplastic fibers can be partially or entirely made from reusable material (from recovered and regenerated fibers). In particular, fibers recovered from recovered fibers, once already used for interior and exterior decoration of a vehicle, can be suitably applied.

The polyester fiber described above is not particularly limited provided that it is made of a polyester resin. Such a polyester resin is not particularly limited provided that it is a polymer resin that contains repeating structural units containing ester bonds, and may be a resin that contains ethylene terephthalate as the main repeating structural units of the dicarboxylic acid component and glycol component. Alternatively, the polyester fiber may be a biodegradable polyester fiber made of polycaprolactone, polyethylene succinate, polybutylene succinate, polyethylene adipate, polybutylene adipate, a polyethylene succinate / adipate copolymer or polylactic acid, or a polyester fiber synthesized with another polyester polymer 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 may be partially replaced by adipic acid, sebacic acid, dimeric acid, sulfonic acid, or metal-substituted isophthalic acid. The glycol component may additionally be partially replaced by diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol or polyalkylene glycol.

Typically, the polyester fiber is produced using a polyester resin according to a well-known spinning method, such as melt spinning. Examples of such a polyester fiber include polyethylene terephthalate (PET) fiber, polybutylene terephthalate (PBT) fiber, polyethylene phthalate (PEN) fiber, polycyclohexylene dimethylene terephthalate (PCT) fiber, polytrimethylene terephthalate (PTT) fiber, and polytrimethylene trimethylene fiber. Of these, polyethylene terephthalate (PET) fiber is preferably used. The polyethylene terephthalate fiber may contain, for example, conventional antioxidants, chelating agents, ion exchange agents, coloring agents, waxes, silicone oil or various surfactants, as well as particles such as various inorganic particles, for example titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin and zirconic acid, crosslinked polymer particles and particles of various metals. Polypropylene fiber is not particularly limited provided that it is made of polypropylene resin. The polypropylene resin is not particularly limited provided that it is a polymer resin that contains repeating structural units containing the following structure: —CH (CH ₃ ) CH ₂ -. Examples of such a polypropylene resin include polypropylene resins and resins based on propylene olefin copolymers, such as resins based on a copolymer of propylene and ethylene. Polypropylene fiber is produced using such a polypropylene resin according to a well known molding method, such as melt spinning. Additionally, the polypropylene fiber may contain the various additives mentioned above that can be added to the polyester fiber.

Examples of nylon fiber include fibers made from nylon resins or nylon copolymer resins such as polycaproamide (nylon-6),

polyhexamethylene adipamide (nylon-66),

polytetramethylendipamide (nylon-46),

polyhexamethylene sebacamide (nylon-610),

polyhexamethyleneendodecamide (nylon 612),

polyundecanamide (nylon 11), polydodecanamide (nylon 12),

poly (m-xylene adipamide) naya (nylon MXD6),

polyhexamethylene terephthalamide (nylon 6T),

polyhexamethylene isophthalamide (nylon 61),

poly (xylene adipamide) (nylon XD6), copolymer

polycaproamide / polyhexamethylene terephthalamide (nylon 6 / 6T), copolymer

polyhexamethylene adipamide / polyhexamethylene terephthalamide (nylon 66 / 6T), copolymer

polyhexamethylene adipamide / polyhexamethylene isisophthalamide (nylon 66/61), copolymer

polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide (nylon 66/61/6), copolymer

polyhexamethylene terephthalamide / polyhexamethylene isisophthalamide (nylon 6T / 6I), copolymer

polyhexamethylene terephthalamide / polydodecanamide (nylon 6T / 12), copolymer

polyhexamethylene adipamide / polyhexamethylene terephthalamide /

polyhexamethylene isophthalamide (nylon 66 / 6T / 6I) and a copolymer of polyhexamethylene terephthalamide / poly-2-methylpentamethylene terephthalamide (nylon 6T / m5T). Nylon fiber is produced using such a nylon resin according to a well-known method, such as melt spinning. Additionally, the nylon fiber may contain the above additives, which can be added to the polyester fiber.

The fiber length and fineness of the thermoplastic fiber are not particularly limited and are accordingly determined according to compatibility with other synthetic fibers or according to the applications of the resulting flame retardant nonwoven materials. However, the length of the thermoplastic fiber is preferably 10 mm or more. The thermoplastic fiber can be either a thread or a staple fiber. In the case of staple fiber, the fiber length is preferably from 10 to 100 mm, in particular, preferably from 20 to 80 mm. In the production of non-woven material by weaving staple fibers with a fiber length of 10 mm or more, it is possible to prevent shedding of staple fiber in the non-woven material. A longer fiber length improves the sound absorption of the nonwoven, but tends to degrade the spinning behavior (for example, with a carding machine) and slow the spread of the flame. Therefore, the fiber length of the thermoplastic staple fiber is preferably 100 mm or less. The fineness of the thermoplastic fiber is from 0.5 to 30 decitex, preferably from 1.0 to 20 decitex, in particular, preferably from 1.0 to 10 decitex.

The thermoplastic staple fibers mentioned above can be used in pure form or in combination with two or more types of fibers. For example, you can mix thermoplastic staple fibers that are of the same type, but differ in the fineness or length of the fiber, or you can mix thermoplastic staple fibers that are different in type, as well as the fineness or length of the fiber. In any case, the ratio of the components in the mixture of such staple fibers is not particularly limited and can be appropriately determined according to the applications or purposes of the resulting nonwoven materials.

To obtain a more flame retardant non-woven material, the thermoplastic staple fiber is preferably interwoven and combined with a heat-resistant staple fiber. Heat-resistant staple fiber has a LOI (oxygen limit index) value of at least 25 and does not include fibers that become flame retardant by adding a flame retardant, such as flame retardant artificial fiber, flame retardant fiber based on polyvinyl chloride (vignon) and modified acrylonitrile fiber. Here, the LOI index value means the minimum oxygen concentration necessary to maintain combustion of 5 cm or more of the sample and measured according to JIS L 1091. Using such a heat-resistant staple fiber with a LOI index of at least 25, flame propagation can be slowed down for non-woven material . But to obtain an even more flame retardant non-woven material, it is preferable to use heat-resistant staple fiber with a LOI index value of at least 28.

The heat-resistant staple fiber, preferably used in the present invention, is superior to the thermoplastic staple fiber in that it has a low shrinkability, and therefore the resulting non-woven material is difficult to melt and compress when burning. In particular, such a heat-resistant staple fiber preferably has a dry heat shrink of not more than 1% at 280 ° C. Specific examples of such a heat-resistant staple fiber include staple fibers obtained, for example, by slicing at least one type of heat-resistant organic fiber selected from the group consisting of aramid fiber, polyphenylene sulfide fiber, polybenzoxazole fiber, polybenzothiazole fiber, polybenzimidazole fiber, polyether ether fiber, polyarylate fiber, polyimide fiber, fluorine-containing fiber and flame-retardant fiber at the required fiber length. Such heat-resistant staple fibers include well-known fibers or fibers produced by well-known methods or methods based on such well-known methods, and all of them can be used. Here, the flame retardant fiber is mainly a fiber produced by sintering acrylic fiber at a temperature of 200 to 500 ° C. in an active atmosphere such as air, that is, it is a carbon fiber precursor. For example, mention may be made of flame-retardant fiber manufactured by Asahi Kasei under the brand name "LASTAN ^® " and flame retardant fiber produced by Toho Tenax under the brand name "Pyromex ^® ".

Of these heat-resistant organic fibers, from the point of view of low shrinkability and processability, at least one type of organic fiber selected from the group consisting of aramid fiber, polyphenylene sulfide fiber, polybenzoxazole fiber, polyester ether fiber, polyarylate fiber and flame-retardant fiber is preferably used. In particular, aramid fiber is preferably used.

Aramid fiber includes para-aramid fiber and meta-aramid fiber. In particular, para-aramid fiber is preferably used from the point of view of lower heat shrinkability. Examples of a para-aramid fiber suitable for use include commercially available products such as polyparaphenylene terephthalamide fiber (manufactured by EI DU PONT and DU PONT-TORAY Co., Ltd. under the trade name Kevlar "KEVLAR ^® ") and polyparaphenylene-3 copolymer , 4′-oxydiphenylene terephthalamide fiber (manufactured by TEIJIN under the brand name "TECHNORA ^® ").

Such an aramid fiber may contain a film former, an organosilicon sizing agent, and a surfactant on the surface or inside the fiber. The dry matter amount of such surface treating agents attached to the aramid fiber is preferably in the range of 0.01 to 20% by weight relative to the amount of aramid fiber.

The fiber length and fineness of the heat-resistant staple fiber are not particularly limited and are accordingly determined according to the compatibility of the fiber with the thermoplastic staple fiber used together or according to the applications of the resulting sound-absorbing material. The fineness of the heat-resistant staple fiber is from 0.1 to 50 decitex, preferably from 0.3 to 30 decitex, more preferably from 0.5 to 15 decitex, in particular preferably from 1.0 to 10 decitex. The flame retardation mechanism in the nonwoven fabric according to the present invention is not clear, however, it can be considered that a heat-resistant staple fiber interwoven with a thermoplastic staple fiber performs the function of inhibiting the combustion of a thermoplastic staple fiber. The fiber length of the heat-resistant staple fiber is not particularly limited, but is preferably from 20 to 100 mm, in particular from the point of view of flame retardation and efficiency, it is preferably from 40 to 80 mm.

The heat-resistant staple fibers mentioned above can be used alone or in combination with two or more types of fibers. For example, you can mix heat-resistant staple fibers that are of the same type, but differ in the fineness or length of the fiber, or you can mix heat-resistant staple fibers that are different in type and also in fineness or length of the fiber. In any case, the ratio of the components when mixing such staple fibers is not particularly limited and, accordingly, can be determined according to the applications or purposes of the resulting sound-absorbing material.

The thermoplastic staple fiber and the heat-resistant staple fiber used in the present invention are preferably mixed in a weight ratio of 95: 5 to 55:45. If the ratio exceeds 95 wt.%, The flame retardation in the nonwoven fabric is insufficient, since leakage is likely to occur. That is, by providing a canvas with a heat-resistant staple fiber content of 5 wt.% Or more, and when the heat-resistant staple fiber is interwoven with a thermoplastic staple fiber, the burning and melting of the thermoplastic staple fiber can be prevented. On the other hand, if the ratio is less than 55 wt.%, The non-woven material has excellent characteristics in terms of slowing down the spread of flame, but due to the decrease in economic efficiency, it is not very suitable for manufacturability, which allows the production of non-woven material of the required size. Therefore, from the point of view of flame retardation and manufacturability, the mass ratio of thermoplastic staple fiber to heat-resistant staple fiber is more preferably 88:12 to 55:45, even more preferably 85:15 to 55:45, and most preferably 85:15 to 65:35.

In the present invention, to improve the wear resistance and sound absorption characteristics of the nonwoven material, it is preferable that the thermoplastic staple fiber contains a high (thin) number thermoplastic staple fiber. As the high-numbered thermoplastic staple fiber, at least one type of fiber selected from the aforementioned can be mentioned: polyester fiber, polypropylene fiber and polyethylene fiber, fiber of linear low density polyethylene and fiber of ethylene / vinyl acetate copolymer.

The fineness of the high-number thermoplastic staple fiber used in the present invention is usually from 0.1 to 15 decitex, preferably from 0.5 to 6.6 decitex, and in particular from 1.1 to 3.3 decitex. If the fineness of a thermoplastic staple fiber with a high number is too low, manufacturability is degraded. On the other hand, if the fineness of a thermoplastic staple fiber with a high number is too large, the sound absorbing performance is degraded. The length of the high-numbered thermoplastic staple fiber is not particularly limited and can accordingly be determined according to compatibility with the heat-resistant staple fiber used and according to the applications of the resulting sound-absorbing material. However, the length of the high-numbered thermoplastic staple fiber is usually preferably from 10 to 100 mm, in particular, preferably from 20 to 80 mm.

In the case where the thermoplastic staple fiber with a high number in the canvas is a mixture, the content (ratio of components) of the thermoplastic staple fiber with a high number is preferably from 30 to 70 wt.%, More preferably from 30 to 50 wt.% Of the total thermoplastic staple fiber.

In the present invention, the weight of the nonwoven material is from 150 to 800 g / m ² . If the weight of the nonwoven material is too small, the suitability for processing during production deteriorates, for example, maintaining the shape of the canvas layer deteriorates. On the other hand, if the weight of the nonwoven material is too large, the energy required to weave the fibers increases, or the weave of the fibers is insufficient, so that defects in the processing of the nonwoven material, such as deformation, occur.

It should be noted that the canvas can be made using a traditional canvas forming machine according to the traditional method of forming the canvas. For example, a mixture of thermoplastic staple fiber and heat-resistant staple fiber is carded in a carding machine to form a canvas.

The nonwoven fabric, preferably used in the present invention, can be formed, for example, by needle-piercing or by water-bonding a canvas obtained by mixing a thermoplastic staple fiber with a heat-resistant staple fiber to weave and join the fibers together. By subjecting the web to a piercing treatment to weave the fibers together, the wear resistance of the nonwoven fabric can be improved.

Needling can be subjected to either one or both surfaces of the canvas. At this stage, if the needle puncture density is too low, the wear resistance of the nonwoven material becomes unsatisfactory. On the other hand, if the needle puncture density is too high, the bulk density and volume fraction of air in the non-woven material is reduced, thereby deteriorating the heat-insulating properties and the sound-absorbing properties of the non-woven material. Therefore, the needle puncture density is preferably from 50 to 300 punctures / cm ² , more preferably from 50 to 100 punctures / cm ² .

In the present invention, needle piercing can be carried out using a conventional needle piercing machine according to a conventional needle piercing method.

Bonding with water jets can be carried out according to the traditional method of bonding with water jets, for example, by means of a water-jet machine for spraying high-pressure water flows from 90 to 250 kg / cm ² G from a plurality of nozzles with diameters from 0.05 to 2.0 mm, arranged in a line or in several lines with intervals from 0.3 to 10 mm. The distance between the nozzles and the canvas is preferably about 1 to 10 cm.

Canvas subjected to needle-bonding or water-jet bonding can be dried in the traditional way and then, if necessary, subjected to heat setting.

In the case where the nonwoven material consists of staple fiber, if its bulk density is too low, flame retardation, thermal insulation and sound absorption are impaired. On the other hand, if its bulk density is too high, flame retardation, wear resistance and processability are impaired. Therefore, it is necessary that the non-woven material of staple fiber has a bulk density of from 0.01 to 0.2 g / cm ³ . Preferably, the bulk density of the nonwoven staple fiber material is from 0.01 to 0.1 g / cm ³ , more preferably from 0.02 to 0.08 g / cm ³ , even more preferably from 0.02 to 0.05 g / cm ³ . By adjusting the bulk density of the nonwoven material in a certain range to control the fraction of air (oxygen) contained in the nonwoven material, it is possible to provide excellent nonwoven material characteristics in terms of flame retardation, thermal insulation and sound absorption.

Additionally, in the present invention, in the case where heat resistance or wear resistance is important for a sound-absorbing material, the nonwoven fabric preferably consists of heat-resistant fiber. The heat-resistant fiber can be either a staple fiber or a thread. Examples of such a heat-resistant fiber include the aforementioned heat-resistant organic fibers. In this case, the nonwoven material is typically produced using such a heat-resistant fiber according to a well-known method.

In the present invention, a thicker non-woven material makes sound absorption better, however, from the point of view of, for example, economic efficiency, ease of processing and space reserved for the sound-absorbing material, the thickness of the non-woven material is preferably from 2 to 100 mm, more preferably from 3 to 50 mm, even more preferably from 5 to 30 mm.

As described above, the sound-absorbing material according to the present invention has a layered structure comprising non-woven material and surface material. The surface material must have a breathability of not more than 50 cc / cm ² / s, measured according to JIS L-1096. There is no lower limit for the breathability of the surface material, however, the breathability is preferably from 0.01 to 50 cc / cm ² / s, in particular preferably from 0.01 to 30 cc / cm ² / s. If the air permeability exceeds 50 cc / cm ² / s., The sound absorption of the sound-absorbing material is deteriorated.

The material constituting the surface material is not particularly limited, for example, the aforementioned materials for nonwoven fabric can be used. The surface material may be in the form of a material or film. Examples of the material include non-woven materials (including plain paper and polyester paper), woven materials, and knitted materials. Examples of films include polyester films. The fiber constituting such a material may be either a staple fiber or a thread. In the case where a material is used as the surface material, the surface material and the nonwoven fabric arranged in layers on the surface material are made of the same material or different materials. For example, in the case where the sound-absorbing material according to the present invention is used as a material for interior decoration of a vehicle, the surface material and the nonwoven fabric arranged in layers on the surface material are preferably made of the same material. The reason is that in this case a large amount of sound-absorbing material is used, and the sound-absorbing material used as the material for the interior decoration of the vehicle must be recycled. For example, in the case where the nonwoven material contains a polyester material, the surface material is preferably made of polyester.

Preferred examples of surface material include nonwoven fabrics from spunbond filaments, non-woven dry layered staple fibers, and non-woven wet layered staple fibers. In particular, non-woven materials from spunbond yarns and preferably non-woven materials of a wet lay-up of staple fiber are preferably used. Non-woven materials from spunbond filaments are produced by the molding method. Of such non-woven materials from spunbond yarns, the materials obtained by partially bonding the fibers to each other through a heat bonding method for combining the canvas are particularly preferred. Essentially, a nonwoven fabric can be used, for example, a commercially available polyester nonwoven fabric spunbond production method (manufactured by TORAY Industries, Inc. under the trademark "Axtar"). As the non-woven material of the dry laying of staple fiber, it is preferable to use material produced by needle-piercing the canvas. Examples of a non-woven material of a wet staple lay-up include paper and felt made from chopped fibers, pulp or staple fibers by a paper-making process.

In the present invention, a non-woven material consisting of a heat-resistant fiber with a LOI of at least 25 and silicate mineral raw materials can be used as a surface material, and such non-woven material is preferably a non-woven wet lay-out material. Such a preferred non-woven fabric can be produced using heat-resistant fiber with a LOI of at least 25 and silicate mineral stock according to the well-known wet process. A “heat-resistant fiber with a LOI of at least 25” may be a staple fiber for which the definition of the LOI is the same as described above. Examples of heat-resistant fibers include the aforementioned heat-resistant organic fibers. As silicate mineral raw materials, mica is preferably used. Specific examples of mica include colorless muscovite, bronze mica, black mica (biotite), and artificial bronze mica. The amount of silicate mineral raw material used is from 5 to 70% by weight, preferably from 10 to 40% by weight, based on the amount of surface material.

A preferred nonwoven wet lay-up material to be used as a surface material preferably consists of a heat-resistant staple fiber with a LOI of at least 25. Examples of such heat-resistant staple fibers include the aforementioned heat-resistant staple fibers. Of these heat-resistant staple fibers, aramid staple fiber is preferably used, and more preferably para-aramid staple fiber is used. Alternatively, the wet nonwoven fabric may be a nonwoven fabric consisting of heat-resistant staple fiber with a LOI of at least 25 and silicate mineral raw materials. Such a wet nonwoven fabric is produced according to the well-known wet paper making method using heat-resistant staple fiber with a LOI index value of at least 25, or using heat-resistant staple fiber with a LOI index value of at least 25, and silicate mineral raw materials. As silicate mineral raw materials, mica is preferably used. Specific examples of mica include colorless muscovite, bronze mica, black mica, and artificial bronze mica. The amount of silicate mineral raw material used is from 5 to 70% by weight, preferably from 10 to 40% by weight, based on the amount of surface material.

The nonwoven material to be used as a surface material is preferably a blank paper in which the total number of dust particles with a diameter of 0.3 μm or more formed in the dust test described later is not more than 500 particles / 0.1 ft ³ (more preferably 100 particles / 0.1 ft ³ or less). Such blank paper may be commercially available, and examples thereof include blank paper manufactured by Fuji Paper Co., Ltd. under the trademark OK Clear White, non-woven spun yarn manufactured by TORAY Industries, Inc. under the trademark "Axtar G2260-1S", and aramid staple fiber non-woven fabric manufactured by OJI PAPER Co., Ltd. under the trademark "KEVLAR Paper".

The thickness of the surface material is not particularly limited, however, it 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 from about 0, 03 to 0.1 mm. The mass of surface material per unit area is preferably as light as possible, however, in terms of strength, it is from about 10 to 400 g / m ² , preferably from about 20 to 400 g / m ² , more preferably from about 20 to 100 g / m ² .

In the present invention, the nonwoven material can take various forms, such as a polyhedron (for example, hexagons, such as a rectangular box), a column, and a cylinder. In the case where the nonwoven material of the sound-absorbing material according to the present invention is a polyhedron, the surface material can be layered on one of the faces of the polyhedron (for example, a rectangular parallelepiped), or the surface material can be layered on two or more faces of the polyhedron. In the case where the nonwoven material is in the form of a column or cylinder, the surface material is preferably layered on the curved surface of the column or cylinder.

The surface material and the nonwoven material can be laminated together in a state where they are not bonded to each other, however, it is preferable to laminate them together in a state where they are bonded to each other in a conventional bonding manner. As a bonding method, mention may be made of bonding using resin rivets (for example, Bano'k material manufactured by Japan Bano'k), fusion, stitching, needle piercing, bonding using adhesives, thermal embossing, ultrasonic welding, bonding by sintering with the use of adhesive resins or bonding by means of a welding machine. In addition to these methods, it is also possible to apply a bonding method in which a material with a low melting point, such as a net material with a low melting point, a film with a low melting point or a fiber with a low melting point, located between the surface material and the nonwoven material, melts during heat treatment while bonding the surface material to the nonwoven material with a low melting point material. Here, the melting point of a material with a low melting point is preferably lower than the melting point of another fiber used in non-woven material or in surface material by 20 ° C or more. It should be noted that in the case where sinter bonding is used as the bonding method, a high-temperature adhesive resin powder (e.g., nylon 6, nylon 66, polyester) or a low-temperature adhesive resin powder (e.g. EVA (low point ethylene-vinyl acetate copolymer) is preferably used melting)). In the case of bonding using adhesives, either thermoplastic adhesives or thermoset adhesives can be used. In this case, for example, after applying the thermosetting epoxy resin to the surface material or non-woven material, layers of the surface material and non-woven material are placed together and then subjected to heat treatment to cure the resin.

A higher degree of bonding between the surface material and the nonwoven material (a larger number of bonding points or a larger bonding surface area) provides a stronger bonding of the surface material and the nonwoven material, however, if the bonding between them is too high, the sound absorption coefficient of the resulting sound absorbing material decreases. In the case where there is no bond between the surface material and the nonwoven material, the sound absorption coefficient of the resulting sound absorbing material increases, however, problems arise such as delamination during use and poor suitability for processing. From this point of view, the number of bonding points between the surface material and the nonwoven material is at least 1 point / cm ² , however, preferably no more than 30 points / cm ² , more preferably no more than 20 points / cm ² , even more preferably no more 10 dots / cm ² . The surface area of the bonding point (s) is preferably minimized, since if the surface area of the bonding point (s) is too large, the sound absorption coefficient of the resulting sound absorbing material is reduced. For example, if the total surface area of the attachment points of the points is designated as B, and the total surface area of the attachment points and points without attachment is designated A + B, then the ratio of the total surface area of the attachment points (B) to the total surface area of the attachment points of the points and non-attachment points (A + B), that is, the ratio expressed by the formula: {B / (A + B)} × 100 (%) is preferably not more than 30%, more preferably not more than 20%, even more preferably not more than 10% . To reduce the number of bonding points or the degree of bonding, it is preferable to use, for example, a material with a low melting point in the form of a mesh or a small number of particles of material with a low melting point and with a relatively large particle size.

In the sound-absorbing material according to the present invention, the surface material must be layered on at least one side of the non-woven material, however, it is possible to lay on both sides of the non-woven material. Additionally, the sound-absorbing material according to the present invention may have a multilayer structure in which at least one or more layers of non-woven material and at least one or more layers of surface material are layered and joined together. In this case, the number of layers, in particular, is not limited.

If necessary, the sound-absorbing material according to the present invention can be colored with dyes or pigments. In the case where a dyed sound-absorbing material is produced, yarn dyed in bulk is obtained by molding a polymer mixed with a dye or pigment, or fibers dyed in various ways can be used. Alternatively, the sound absorbing material itself can be dyed 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 flame inhibitor, such as a phosphate-based flame inhibitor, a halogen-based flame inhibitor or a hydrated compound metal, to further improve its ability to slow the spread of flame or its wear resistance.

The sound-absorbing material according to the present invention can be used in various fields by molding to give it the desired size or shape, for example, using a well-known method according to its purpose or scope. Sound absorbing material according to the present invention can be applied in all areas requiring slowing down the spread of flame and sound absorption. For example, the sound-absorbing material according to the present invention is expediently used for interior decoration materials of transport equipment, such as vehicles (e.g., cars and trucks), boats and ships, aircraft, and for civil engineering construction materials (e.g., materials for walls and materials for the ceiling). In particular, the use of the sound-absorbing material according to the present invention as the interior decoration material of the vehicle engine compartment makes it possible to prevent the spread of flame when the flame breaks into the engine compartment and to prevent the noise of the engine compartment coming from the engine compartment. In addition, the sound-absorbing material according to the present invention can also be used for various applications, such as materials for lining vehicles, floor materials, rear equipment and door trim; insulation materials for the front panels of cars, trains and aircraft; 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 dryers and electric lawn mowers; screens for speakers; and for areas related to civil engineering with construction machinery, such as crushers (e.g. frame cladding).

The sound-absorbing material according to the present invention obtained using pure paper as a surface material, in particular, sound-absorbing material containing clean paper as a surface material and a nonwoven material in which a polyester staple fiber is interwoven with an aramid staple fiber, is preferably used as a sound-absorbing material for machinery and equipment for air conditioning in clean rooms and in the construction of clean rooms.

When sound-absorbing material is used, it is preferable that the rear surface of the sound-absorbing material according to the present invention (i.e., the surface of the sound-absorbing material from the non-woven side) or its end surface is attached to a structural member such as a reflector or a mounting plate. Examples of material for the “structural element” include metals such as aluminum, resins such as rubber, and wood. The shape of the “structural element” is not particularly limited, and the “structural element” may have either a carcass shape or a skin shape. In the present invention, the “structural element” is preferably a reflector. The reflector will be described later in this description.

Examples of a reflector include metal and resin-based boards. As the metal plate, a well-known metal plate can be used, provided that it is made of a metal material and made in the form of a plate, and the type of metal and the size of the metal plate are not particularly limited. Examples of such a metal plate include metal plates made of stainless steel, iron, titanium, nickel, aluminum, copper, cobalt, iridium, ruthenium, molybdenum, manganese and alloys consisting of two or more of these metals and composites made from such metal and carbon and shaped plates. As the resin-based board, a well-known resin-based board may be used provided that it is made of resin and formed into a board, the type of resin and the board size, mechanical properties and additives to the resin board are not particularly limited. Examples of such a resin based board include synthetic resin based boards, fiber reinforced resin based boards, and rubber boards.

A synthetic resin board is produced by molding a synthetic resin into a plate according to a well-known molding method. Examples of synthetic resins include thermoplastic resins and thermosetting resins.

Examples of thermoplastic resins include polyester resins such as polyethylene terephthalate (PET) resins, polybutylene terephthalate (PBT) resins, polytrimethylene terephthalate (PTT) resins, polyethylene naphthalate (PEN) resins, and liquid crystal polyester resins, polyolefin resins such as polyethylene (polyethylene) polypropylene (PP) resins and polybutylene resins; styrene-based resins, polyoxymethylene (POM) resins, polyamide (PA) resins, polycarbonate (PC) resins, polymethyl methacrylate (PMMA) resins, polyvinyl chloride (PVC) resins, polyphenylene sulfide (PPS) resins, polyphenylene ether (PPE) resins, polyphenylene ether (PPE) resins ) resins, polyimide (PI) resins, polyamide imide (PAI) resins, polyester imide (PEI) resins, polysulfone (PSU) resins, polyethersulfone resins, polyketone (PK) resins, polyester ketone (PEK) resins, polyetheretherketone (PEEK) resins, polyarylate ( PAR) resins, polyether nitrile (PEN) resins, phenolic resins (e.g. slabs based on novolac phenolic resins), phenoxy resins and fluoride resins, polystyrene-based thermoplastic elastomers, based on polyolefins, based on polyurethane, based on polyesters, based on polyamides, based on polybutadiene, based on polyisoprene and based on fluorine-containing polymers, and resins based on copolymers and their modified resins.

Examples of thermosetting resins include phenolic resins, epoxy resins, epoxy acrylate resins, polyester resins (e.g., unsaturated polyester resins), polyurethane resins, diallyl phthalate resins, silicone resins, vinyl ester resins, melamine resins, polyimide resins, polybismaleimide triazine (BT) resins, cyanate resins (e.g. resins based on cyanic acid esters), resins based on their copolymers, their denatured resins and mixtures thereof.

A fiber reinforced resin board is not particularly limited provided that it consists of fiber and resin (for example, the thermosetting resin mentioned above) and is made in the form of a plate. As such a fiber reinforced resin-based board, a well-known fiber-reinforced resin based board can be used. Typically, such a fiber reinforced resin board is produced according to a well-known method, that is, by impregnating a fiber or fiber product with a prepreg (i.e., an uncured thermosetting resin) and then curing it by heating. The fiber used as the starting material may be either a staple fiber or a thread. In any case, the fibrous material is usually produced using the aforementioned synthetic resin according to a well-known method. Examples of the fibrous product include yarns, tows, wovens, knits and nonwovens. Such fibrous products are usually produced using the aforementioned fibers according to a well-known method. Preferred examples of a fiber reinforced resin board include fiber reinforced resin boards consisting of carbon fiber and an epoxy resin (carbon fiber reinforced epoxy resin boards).

Examples of rubber boards include natural rubber boards and synthetic rubber boards.

The resin-based slab described above may be a slab absorbing electromagnetic waves. As the plate absorbing electromagnetic waves, we can mention the well-known plate for absorbing electromagnetic waves, such as described as an example in the published application for Japanese patent No. 2003-152389 "shielding electromagnetic waves, the material molded in the form of a plate."

In the preferred case, to obtain a sound-absorbing panel, the sound-absorbing material according to the present invention is attached to the structural member, for example, the aluminum plate used is attached to the rear surface of the sound-absorbing material, and the structural member in the form of an aluminum frame is attached around the entire periphery of the sound-absorbing material. In this case, such a sound-absorbing panel can be placed, for example, inside the casing of machinery that produces noise, or can be used as a partition.

Examples

The present invention will now be described in more detail with reference to the following examples and comparative examples, however, the present invention is not limited to the examples only. It should be noted that the characteristic values in the examples and examples for comparison are obtained according to the following methods.

(Breathability)

The breathability of the surface material was measured using a conventional method according to JIS L-1096.

(Sound Absorption Rate)

Sound absorption coefficients of sound-absorbing material at normal incidence were measured for various frequencies using an automatic device (manufactured by SOTEC Co., Ltd.) to measure the sound absorption coefficient at normal incidence using the “Sound Absorption Test Method for Building Materials at Normal Incidence by Tubular Method” according to JIS A1405 . The measurement was carried out by installing sound-absorbing material in the measuring device in such a way that its surface material was directed to the sound source.

(Thickness)

The thickness of both the surface material and the nonwoven material was measured under a load of 0.1 g / cm ² using a compressive strength meter (manufactured by Daiei KagakuSeiki MFG. Co., Ltd.).

(Dry heat shrink at 280 ° C)

The fiber length was measured before and after heating the fiber at 280 ° C. for 30 minutes in air, and fiber shrinkage was determined based on the fiber length measured before heating.

(Degree of dust formation)

The degree of dust formation of the surface material was measured by the rotary drum treatment method according to JIS B 9923. First, a device for measuring the dust generation of the drum type in a clean room in an idle state was checked to ensure that there was no dust in the measuring device. Then, the surface material (20 cm × 28.5 cm), which was not washed completely, was placed in a drum type dust formation measuring device (CW-HDT101), and the measuring device was driven at a drum rotation speed of 46 rpm. After 1 minute from the start of operation at a speed of 0.1 ft ³ / min, the number of dust particles was measured every minute. The measurement of the number of dust particles for 1 minute was continuously performed 10 times and the average value was determined as the number of dust particles generated per minute. A 82-3200N counter was used as a dust particle counter, and the maximum intake air volume at the time the filter was used was 2.2 l / min. Five samples were taken for research, each 20 cm × 28.5 cm in size. The number of dust particles generated was expressed as the number of dust particles generated in a 1 cm × 1 cm sample. As shown in Table 1, the degree of dust formation was calculated in accordance with 5 categories as the total number of dust particles with a diameter of 0.3 μm or more. Category 4 or 5 paper was defined as blank paper.

Table 1 Category Total number of dust particles (particles / 0.1 ft ³ ) 5 100 or less four 101 to 500 3 501 to 1000 2 1001 to 5000 one 5001 or more

Example 1

Blended para-aramid staple fiber manufactured by DU PONT-TORAY Co., Ltd. under the brand name “KEVLAR®” (1.7 decitex × 51 mm, dry heat shrinkage at 280 ° C: 0.1% or less, LOI index value: 29) and polyethylene terephthalate (PET) staple fiber (1.7 decitex × 51 mm), manufactured by TORAY Industries, Inc., in a mass ratio of 30:70, thereby producing, by needle piercing, a PET / aramid nonwoven material with a thickness of 10 mm and a weight per unit area of 400 g / m ² . The bulk density of the obtained nonwoven material was 0.04 g / cm ³ .

At the same time, yarn of 3 mm chopped para-aramid fiber was mixed with 1.7 decitex single yarn fineness (“KEVLAR®” manufactured by DU PONT-TORAY Co., Ltd.) and meta-aramide fiber (Nomex® manufactured by Nomex® USA DU PONT) pulp in a mass ratio of 90:10, then subjected to processing by means of a paper-making method and calendering, while receiving as a surface material aramid paper with a thickness of 95 μm, a mass per unit area of 71 g / m ² and breathability of 0.81 cubic meters .cm / cm ² / s. A low melting point ethylene-vinyl acetate (EVA) copolymer powder (melting point: 80 ° C) was poured onto the surface material at a rate of 75 g / m ² , and then a layer of needle-punched PET / aramide non-woven material was applied to the surface material. The surface material and non-woven material were placed in the middle between the metal wire mesh and then heat-treated at 160 ° C for 3 minutes to bond them together, thereby obtaining a sound-absorbing material "(PET / aramid non-woven material) / aramid paper".

Example 2

Polyethylene terephthalate (PET) non-woven material with a thickness of 10 mm, a mass per unit area of 400 g / m ² and a bulk density of 0.04 g / cm ^{3 was} obtained by needle piercing from polyethylene terephthalate (PET) staple fiber (1.7 decitex × 51 mm) produced by TORAY Industries, Inc. On the other hand, polyethylene terephthalate (PET) non-woven spunbond material (“Axtar® G2260” manufactured by TORAY Industries, Inc.) with a thickness of 560 μm, a mass per unit area of 260 g / m ² and breathability 11 was obtained as a surface material 5 cc / cm ² / s. In the same manner as in Example 1, the surface material was bonded to needle-punched PET non-woven material, thereby obtaining the sound-absorbing material “needle punched PET non-woven material / PET non-woven spunbond production method”.

Example 3

Aramid nonwoven fabric with a thickness of 10 mm, a mass per unit area of 400 g / m ² and a bulk density of 0.04 g / cm ^{3 was} obtained by needle piercing, using only the same para-aramid staple fiber (Kevlar "KEVLAR®"), as in example 1. The same aramid paper was obtained as the surface material as in Example 1. In the same manner as in Example 1, the aramid paper as a surface material and the aramid nonwoven material were fastened together, thereby obtaining the sound-absorbing material “aramid nonwoven material / aramid paper” .

Example for comparison 1

Sound absorbing material was obtained in the same manner as in example 1, except that aramid paper was excluded. That is, only non-woven material was obtained containing KEVLAR® staple fiber and polyethylene terephthalate (PET) staple fiber in a weight ratio of 30:70.

Example for comparison 2

A commercially available nonwoven meltblown non-woven fabric (“Thinsulate®” manufactured by Sumitomo 3M Ltd.) was obtained in which polypropylene (PP) and polyethylene terephthalate (PET) were mixed in a weight ratio of 65:35. The nonwoven fabric obtained by the aerodynamic method from a melt had a thickness of 10 mm and a mass per unit area of 240 g / m ² .

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 follows from Table 2, all the sound-absorbing materials in Examples 1-3 are superior to the sound-absorbing materials of the comparative examples.

table 2 Example 1 Example 2 Example 3 Example for comparison 1 Example for comparison 2 Non woven fabric Type of fiber PET / Aramid (70/30) PET Aramid PET / Aramid (70/30) PP / PET (70/30) Weight (g / m ²⁾ 400 400 400 400 240 Thickness (mm) 10 10 10 10 10 Bulk density (g / cm ³ ) 0.4 0.4 0.4 0.4 - Surface material View Aramid paper Nonwoven fabric from PET spunbond production method Aramid paper - - Weight (g / m ²⁾ 71 260 71 - - Thickness (μm) 95 560 95 - - Breathability (cc / cm ² / s) 0.81 11.5 0.81 - - Sound Drop Absorption Rate 1/3 octave frequency band (Hz) 500 11.0 11.0 10.3 8.2 6.3 630 11.3 19.1 11.8 10.1 7.5 800 20.5 32,7 20.3 14.6 10.9 1000 33.3 57.0 32,5 19.5 17.1 1250 44.6 76.1 43.7 25.1 25.7 1600 66,2 86.8 72.5 31.7 34.9 2000 96.5 86.8 98.8 40.3 47.2

Example 4

Polyethylene terephthalate (PET) staple fiber (1.7 decitex × 44 mm) manufactured by TORAY Industries, Inc., polyethylene terephthalate (PET) staple fiber (1.7 decitex × 1 mm) manufactured by TORAY Industries, Inc. and yarn low melting point manufactured by TORAY Industries, Inc. under the trademark "SAFMET" (melting point: 110 ° C, 4.4 decitex × 51 mm) were mixed in a mass ratio of 60:20:20, and then subjected to carding to obtain a canvas. Then the canvas was sealed with needle piercing to obtain a nonwoven material. The nonwoven fabric was heat treated at 150 ° C for 3 minutes to melt the yarn with a low melting point so that the other polyester staple fibers were partially bonded together to obtain a nonwoven fabric with a thickness of 10 mm, weight per unit area of 400 g / m ² and bulk density of 0.04 g / cm ³ .

EVA powder “2030-M” manufactured by Tokyo Printing Ink MFG was poured onto the non-woven material thus obtained. Co., Ltd., at a rate of 10 g / m ² , and then continuously heated at 140 ° C for 1 minute. Then, a layer of clean paper manufactured by Fuji Paper Co., Ltd. was placed on the nonwoven material as a surface material. under the trademark “Clean Paper OK clean white” (thickness: 90 μm, weight: 70 g / m ² , breathability: 0.15 cc / cm ² / s), and then fastened them together crimping using a cooling roller, while receiving sound-absorbing material. The dusting characteristics of clean paper used as surface material are given below. The degree of dust formation of clean paper received category 5.

Table 3 Particle Diameter (μm) 0.3 0.5 1,0 2.0 5,0 10.0 General Particle number eleven 8 eleven 9 2 0 41

Example 5

The same non-woven material as the material used in Example 1 and the non-woven material of polyethylene terephthalate (PET) filament yarn produced by TORAY Co., Ltd. under the trademark "Axtar® G2260-1S" (thickness: 620 μm, weight: 260 g / m ² , breathability: 11 cc / cm ² / s), as a material, the surfaces were fastened together in the same manner as in the example 1, while receiving sound-absorbing material. The dusting characteristics of the surface material are shown below. The degree of dust formation of the surface material received category 4.

Table 4 Particle Diameter (μm) 0.3 0.5 1,0 2.0 5,0 10.0 General Particle number one hundred fifty 102 39 8 one 318

Example 6

The same non-woven material as the material used in Example 1 and 100% KEVLAR® paper manufactured by OJI Paper Co., Ltd. (thickness: 95 μm, weight: 72 g / m ² , breathability: 0.93 cu. cm / cm ² / s), as a material, the surfaces were fastened together, thus obtaining a sound-absorbing material. The nonwoven fabric and the surface material were bonded together using a NISSEKI Conwed net ON5058 net material manufactured by NISSEKI PLASTO Co., Ltd. In particular, Conwed net mesh was placed on a nonwoven fabric and then heated at 150 ° C. for 1 minute until the surface of the Conwed net mesh melted. Then, surface material was mixed on a Conwed net mesh material and squeezed by a cooling roller to bond the surface material to a nonwoven fabric.

The nonwoven fabric and the surface material were bonded using Conwed net mesh cells with a mesh size of 8 mm.

The ratio of the total surface area of the fastening points of KEVLAR® paper and non-woven fabric using Conwed net (B) mesh to the total surface area of the fastening points and non-bonded points (A + B), i.e. the ratio expressed by the formula: (B / (A + B)> 100 (%) was 2%.

Example 7

The same nonwoven material as the material used in Example 1 and the same aramid paper as the paper of Example 1 were bonded together as a surface material, thereby obtaining a sound-absorbing material. The nonwoven fabric and surface material were fastened together by double-sided adhesive tape. In particular, a double-sided adhesive tape was glued to a surface material and a layer of nonwoven material was placed on it. Then, the surface material and the nonwoven fabric were compressed by means of a roller to bring them into complete and strong contact with each other.

The ratio of the total surface area of the bonding points (B) to the total surface area of the bonding points and points without bonding (A + B) was 100%.

Sound absorption coefficients during normal incidence of sound absorbing materials according to examples 4-7 are shown in table 5.

Table 5 Example 4 Example 5 Example 6 Example 7 Non woven fabric Type of fiber Mixed PET PET / Aramid (70/30) PET / Aramid (70/30) PET / Aramid (70/30) Weight (g / m ²⁾ 400 400 400 400 Thickness (mm) 10 10 10 10 Bulk density (g / cm ³ ) 0.4 0.4 0.4 0.4 Surface material View Commercially available aramid paper Nonwoven fabric from PET spunbond production method KEVLAR® paper Aramid paper Weight (g / m ²⁾ 70 260 72 71 Thickness (μm) 90 620 95 95 Breathability (cc / cm ² / s) 0.15 eleven 0.93 0.81 Sound Drop Absorption Rate 1/3 octave frequency band (Hz) one hundred 3,7 3.6 4.3 4,5 125 3.0 3.0 3.9 4.3 160 3.4 3,5 4.0 4.0 200 3.6 3.8 4.9 4.4 250 4.2 5.5 5.8 5.2 315 3.3 4.8 5.1 4.9 400 5.5 7.1 7.3 10.0 500 9.2 11.0 11.0 13.3 630 8.9 19.1 11,4 24.5 800 13.8 32,7 19.2 37.1 1000 19.6 57.0 26.0 38.8 1250 33.1 76.1 44.9 56.9 1600 53.5 86.8 69.1 53.6 2000 84.9 86.8 96.0 70.3

Example 8

In the same manner as in Example 1, the same aramid paper as the paper of Example 1 was bonded as a surface material from one of the surfaces of the same nonwoven material as the material of Example 1, thereby obtaining a sample. Additionally, a layer of the same surface material as the material of Example 1 (i.e., aramid paper) was placed on the surface of the nonwoven fabric sample, that is, on the surface opposite to the surface material of the sample surface, and then joined together by heating in the same manner as in example 1, while receiving sound-absorbing material "aramid paper / (PET / aramid non-woven material) / aramid paper".

(Sound transmission loss test)

The sound transmission loss of sound-absorbing materials obtained in Examples 1 and 8 was measured according to JIS A 1416. The measurement results are shown in Table 6.

Table 6 Frequency Hz) 500 1000 2000 3150 4000 5000 6300 8000 Sound loss (dB) Example 1 8.5 14.2 7.9 8.7 10.5 13.3 16.5 19.5 Example 8 8.6 14.0 8.3 11.8 15.1 20.1 24.9 28.7

Example 9

KEVLAR® paper containing mica (manufactured by Du Pont Teijin Advanced Papers) (thickness: 75 μm, weight: 86 g / m ² , breathability: 0 cc / cm ² / s) obtained by papermaking was obtained as a surface material using a mixture of yarn of 5 mm chopped para-aramid fibers (KEVLAR®, manufactured by DuPont Teijin Advanced Papers, Ltd.) with a fine fineness of 1.7 decitex, and mica as a silicate mineral raw material. The surface material was combined with the same non-woven material as the material of Example 1, in which KEVLAR® staple fiber and polyethylene terephthalate (PET) staple fiber were mixed in a weight ratio of 30:70 (thickness: 10 mm, weight: 400 g / m ² ) , in the same manner as in Example 1, using a powder with a low melting point, thereby obtaining a sound-absorbing material with KEVLAR® paper containing mica. The sound absorption coefficients were measured with a normal incidence of such sound-absorbing material, and the measurement results are presented in table 7.

The fire resistance test of sound-absorbing material was carried out according to the test method for burning a sample in the vertical position UL-94. A gas burner was used having a nozzle with an external diameter of 19 mm and an internal diameter of 16.5 mm, and the flame length of the gas burner was set to 140 mm. The sound-absorbing material was kept in the flame of a gas burner at a flame length of 100 mm for 4 minutes so that the sound-absorbing material was perpendicular to the flame (at this time, the surface material was placed on the flame side) to check whether a hole was formed in the surface material and non-woven material. As a result, no hole formation was observed either in the surface material or in the nonwoven layers of the sound absorbing material.

Example 10

Polyethylene terephthalate (PET) staple fiber (1.7 decitex × 44 mm) manufactured by TORAY Industries, Inc., polyethylene terephthalate (PET) staple fiber (1.7.6 decitex × 51 mm) manufactured by TORAY Industries, Inc. and low melting point yarns manufactured by TORAY Industries, Inc. under the trademark "SAFMET" (melting point: 110 ° C, 4.4 decitex × 51 mm) were mixed in a mass ratio of 60:20:20 and then fastened by needle-piercing to obtain a non-woven material with a thickness of 10 mm, weight per unit area of 200 g / m ² and a bulk density of 0.02 g / cm ³ . As the surface material, “100% polyester paper” (thickness: 90 μm, weight: 54 g / m ² , air permeability: 0.9 cc / cm ² / s) manufactured by OJI PAPER Co., Ltd. was used. and the surface material was bonded to the nonwoven material in the same manner as in Example 1, using an EVA powder with a low melting point and thereby obtaining a sound absorbing material “polyethylene terephthalate (PET) nonwoven material / polyester paper”. The sound absorption coefficients of such a sound absorbing material were measured at normal incidence, the measurement results are presented in table 7.

Example 11

Polyethylene terephthalate (PET) staple fiber (1.7 decitex × 44 mm) manufactured by TORAY Industries, Inc., polyethylene terephthalate (PET) staple fiber (1.7.6 decitex × 51 mm) manufactured by TORAY Industries, Inc. and yarn with a low melting point manufactured by TORAY Industries, Inc., trademark SAFMET (melting point: 110 ° C, 4.4 decitex × 51 mm) was mixed in a mass ratio of 60:20:20, and then subjected to carding for receiving the canvas. The canvas was fastened by needle piercing to obtain a nonwoven material. The non-woven material was heated at 150 ° C for 3 minutes to melt the yarn with a low melting point to partially bond together the other polyester staple fibers, thereby obtaining a polyethylene terephthalate (PET) non-woven material with a thickness of 10 mm, weight per unit area of 200 g / m ² and bulk density 0.02 g / cm ³ .

At the same time, yarn from chopped (1.7 decitex × 5 mm) para-aramid fiber (KEVLAR® manufactured by DU PONT-TORAY Co., Ltd.) and meta-aramid fiber pulp (Nomex® manufactured by USA DU) were mixed PONT) at a mass ratio of 95: 5, and then treated the mixture with a paper-making method and calendaring to obtain aramid paper 70 μm thick, with a mass per unit area of 36 g / m ² and air permeability of 20.5 cc / cm ² / s as a surface material. The surface material and the nonwoven material were bonded together in the same manner as in Example 1, thereby obtaining a sound-absorbing material.

Two sheets of the sound-absorbing material thus obtained were placed together in layers and an additional aramid paper consisting of KEVLAR® and Nomex® according to Example 1 was placed below (thickness: 95 μm, weight: 71 g / m ² , breathability: 0.81 cc. cm / cm ² / s) for measuring sound absorption coefficients of the resulting material. The measurement results are presented in table 7.

Table 7 Example 9 Example 10 Example 11 Non woven fabric Type of fiber PET / Aramid (70/30) Mixed PET Mixed PET (two layers) Weight (g / m ²⁾ 400 200 200/200 Thickness (mm) 10 10 10/10 Bulk density (g / cm ³ ) 0.04 0.02 0.02 / 0.02 Surface material Type of KEVLAR® mica paper Polyester paper Aramid paper (three layers) Weight (g / m ²⁾ 86 54 36/36/71 Thickness (μm) 75 90 70/70/95 Breathability (cc / cm ² / s) 0 0.90 20.5 / 20.5 / 0.81 Sound Drop Absorption Rate 1/3 octave frequency band (Hz) one hundred 3.4 4,5 4.3 125 2,8 3.4 3.4 160 3.2 4.3 3.9 200 4,5 5.3 6.1 250 5.8 7.8 10.3 315 5.5 7.1 9.7 400 8.7 10.6 16.1 500 11.1 10.8 21.0 630 17.6 14,4 28.9 800 28.3 25.8 42.6 1000 53.0 40,2 60.1 1250 78.3 45.6 78.9 1600 85.7 55.7 93.2 2000 88.2 76.1 98.4

Example for comparison 3

100% polyethylene terephthalate (PET) non-woven material with a thickness of 2.5 mm, a mass per unit area of 100 g / cm ² and a bulk density of 0.025 g / cm ^{3 was} obtained using the same fibers as the fibers of example 4, with the same the ratio of the components of the mixture, as in example 4, and in the same manner as in example 4. The same surface material (that is, aramid paper), as in example 1, was bonded to a nonwoven material in the same manner as in example 1, obtaining at this is sound absorbing material.

Example for comparison 4

100% polyethylene terephthalate (PET) non-woven material with a thickness of 5 mm, a weight per unit area of 45 g / cm ² and a bulk density of 0.009 g / cm ^{3 was} obtained using the same fibers as in example 4, with the same ratio of the components of the mixture , as in example 4, and in the same manner as in example 4. The same surface material (that is, aramid paper), as the material of example 1, was bonded to the nonwoven material in the same manner as in example 1, while obtaining a sound-absorbing material.

Example for comparison 5

100% polyethylene terephthalate (PET) non-woven material with a thickness of 25 mm, a mass per unit area of 900 g / cm ² and a bulk density of 0.036 g / cm ^{3 was} obtained using the same fibers as in example 4, with the same ratio of the components of the mixture as in example 4, and in the same manner as in example 4. The same surface material (that is, aramid paper) as the material of example 11 was bonded to the nonwoven material in the same manner as in example 1, while obtaining a sound-absorbing material.

Example for comparison 6

A 100% non-woven fabric of wet laying from aramid fiber with a thickness of 5.5 mm, a mass per unit area of 1582 g / m ² and a bulk density of 0.29 g / cm ^{3 was} obtained by paper making using pulp "KEVLAR®" manufactured by USA DU PONT. The same surface material as the material of Example 1 was bonded to the nonwoven material in the same manner as in Example 1, thereby obtaining a sound-absorbing material.

Example for comparison 7

100% polyethylene terephthalate (PET) non-woven material with a thickness of 10 mm, a mass per unit area of 200 g / cm ² and a bulk density of 0.02 g / cm ^{3 was} obtained using the same fibers as the fibers of example 4, with the same the ratio of the components of the mixture, as in example 4, and in the same manner as in example 4. 100% polyethylene terephthalate (PET) surface material with a thickness of 410 μm, a mass per unit area of 59 g / m ² and breathability 93 cc / cm ² / s was obtained using the same fibers as the fibers used in the production of non-woven material according to example 4, with the same ratio of the components of the mixture, as in example 4, and in the usual way, that is, by mixing and needle-piercing the fibers. Thus obtained non-woven material and surface material were bonded together in the same manner as in example 1, using powder with a low melting point and thus obtaining a sound-absorbing material.

Sound absorption coefficients during normal incidence of sound absorbing materials obtained in Examples 3 to 7 are shown in Table 8.

Table 8 Example for comparison 3 Example for comparison 4 Example for comparison 5 Example for comparison 6 Example for comparison 7 Non Woven Material Type of fiber Mixed PET Mixed PET Mixed PET Mixed PET Mixed PET Weight (g / m ²⁾ one hundred 45 900 1582 200 Thickness (mm) 2.5 5 25 5.5 10 Bulk density (g / cm ³ ) 0.04 0.009 0,036 0.29 0.02

Surface material View Aramid paper Aramid paper Aramid paper Aramid paper Needle Punched Non-Woven Fabric Weight (g / m ²⁾ 71 71 36 71 59 Thickness (μm) 95 95 70 95 410 Air permeability (cubic cm / cm ² / s) 0.81 0.81 20.5 0.81 93 Sound Drop Absorption Rate 1/3 octave frequency band (Hz) one hundred 3,1 3,7 5.2 4.4 5.3 125 3.0 2.5 4.2 3.9 4.6 160 2.9 3.0 4.9 4.1 4.7 200 3.3 3.4 6.0 5.9 5,4 250 3.3 3.4 11.1 5.9 6.2 315 2,3 2,4 17.1 5.1 5.3 400 3.4 3.6 28.1 6.6 7.2 500 4.1 4.0 37.6 8.5 9.2 630 3.8 3.4 49.8 8.8 10.3 800 4.9 4.3 58.8 12.0 10.9 1000 7.2 5.9 77.4 16.6 13.8 1250 9.6 7.9 84.7 23.3 16.8 1600 16.1 10,4 90.5 38,2 21.9 2000 28.6 31,0 92.0 27.0 32.8

As follows from tables 7 and 8, the sound-absorbing material of example 11 had a higher sound absorption effect with a relatively low frequency (that is, sound with 1000 Hz or less, in particular 500 Hz or less) compared to other sound-absorbing materials, since the thickness of the sound-absorbing material of example 11 was greater due to its layered structure.

Additionally, the sound-absorbing material, in which the non-woven material had a relatively low weight (comparative example 3), had low sound absorption coefficients, both at low and high frequencies. On the other hand, a sound-absorbing material in which the non-woven material had a relatively large weight (comparative example 5) had a high sound absorption effect due to the larger thickness, however, its large weight created problems in terms of processing and manufacturability. Sound-absorbing material in which the nonwoven material had a relatively low bulk density (comparative example 4) had low sound absorption coefficients, and such sound-absorbing material was more likely to break due to the application of loads. The sound-absorbing material in which the non-woven material had a relatively high bulk density (comparative example 6) was not suitable for processing because it was too stiff and heavy.

Additionally, the sound-absorbing material in which the surface material had an air permeability exceeding 50 cc / cm ² / s (i.e., the sound-absorbing material according to Example 7) did not have increased sound absorption, even if the surface material was bonded to a nonwoven material, since the breathability of the surface material was too large.

Industrial application

Sound-absorbing material according to the present invention is applicable as sound-absorbing material to be used in areas related to electrical appliances, such as air conditioners, electric refrigerators, electric washing machines, audiovisual equipment and electric lawn mowers; transport equipment, such as vehicles, boats and ships, aircraft; and building materials, such as building materials for walls.

Claims (22)

1. Sound-absorbing material in which non-woven material with a mass per unit area of from 150 to 800 g / m ² and bulk density from 0.01 to 0.2 g / cm ³ and a surface material with air permeability of not more than 50 cc are located / cm ² / s, measured according to JIS L-1096, the non-woven material and the surface material are layered by bonding, the number of bonding points of the non-woven material and surface material is not more than 30 dots / cm ² , and the ratio of the total surface area of the bonding points to total surface area Bonding points and points without bonding is not more than 30%. 2. The sound-absorbing material according to claim 1, in which the nonwoven material is a material in which a thermoplastic staple fiber and a heat-resistant staple fiber are interwoven with a LOI index value of at least 25. 3. The sound-absorbing material according to claim 2, in which the weight ratio of thermoplastic staple fiber and heat-resistant staple fiber is in the range from 95: 5 to 55:45. 4. The sound-absorbing material according to claim 2, in which the weight ratio of thermoplastic staple fiber and heat-resistant staple fiber is in the range from 85:15 to 55:45. 5. The sound-absorbing material according to claim 2, in which the thermoplastic staple fiber is at least one type of staple fiber selected from the group consisting of polyester fiber, polypropylene fiber and nylon fiber. 6. The sound-absorbing material according to claim 2, in which the heat-resistant staple fiber is at least one type of staple fiber selected from the group consisting of aramid fiber, polyphenylene sulfide fiber, polybenzoxazole fiber, polybenzothiazole fiber, polybenzimidazole fiber, polyetheretherketone fiber, polyarylate fiber, polyimide fiber, fluorine-containing fiber and flame retardant fiber. 7. The sound-absorbing material according to claim 2, wherein the thermoplastic staple fiber is a polyester staple fiber and the heat-resistant staple fiber is an aramid staple fiber. 8. The sound-absorbing material according to claim 1, in which the non-woven material is obtained by needle piercing or water-jet bonding. 9. The sound-absorbing material according to claim 1, wherein the surface material is a nonwoven spunbond production method or a non-woven staple material of a wet laying. 10. The sound-absorbing material according to claim 9, in which the non-woven material of the wet laying consists of a heat-resistant staple fiber with a LOI index value of at least 25. 11. The sound-absorbing material according to claim 9, in which the non-woven material of the wet laying consists of heat-resistant staple fiber with a LOI index value of at least 25, and silicate mineral raw materials. 12. The sound-absorbing material according to claim 11, in which the silicate mineral raw material is mica. 13. The sound-absorbing material of claim 10, wherein the heat-resistant staple fiber is an aramid staple fiber. 14. The sound-absorbing material according to claim 9, in which the surface material has a dust number of particles with a diameter of not less than 0.3 μm equal to not more than 500 particles / 0.1 ft ³ , measured by the processing method in a rotating drum according to JIS B-9923 6.2 (1.2). 15. The sound-absorbing material according to claim 1, in which the non-woven material and the surface material are made of the same type of synthetic fiber. 16. The sound-absorbing material according to claim 1, in which the nonwoven material is in the form of a polyhedron, and the surface material is layered on two or more faces of the polyhedron. 17. The sound-absorbing material according to clause 16, in which the non-woven material is in the form of a hexagon, and the surface material is layered on both side faces of the hexagon. 18. The sound-absorbing material according to claim 1, in which the nonwoven material is in the form of a column or cylinder, and the surface material is layered on the curved surface of the column or cylinder. 19. The sound-absorbing material according to claim 1 with a multilayer structure, containing at least one or more of each of the layers of non-woven material and surface material in which both layers are combined. 20. The sound-absorbing material according to claim 1, which is used as a material for the interior decoration of the vehicle or material for the external decoration of the vehicle. 21. The sound-absorbing material according to claim 1, which is used as a sound-absorbing material for a lawn mower. 22. The sound-absorbing material according to claim 1, which is used as a sound-absorbing material for the crusher.