JP6900129B2 - Sound absorber - Google Patents

Description

The present invention relates to a sound absorbing body that can be suitably used for building materials (for example, houses, factories, acoustic facilities), automobiles, tires, electric appliances, and the like.

Noise can cause psychological discomfort to a person, causing frustration and stress, and causing illnesses such as headaches and deafness. Therefore, various measures have been taken. The measures taken so far have shown a certain effect in reducing the noise level including the entire frequency range, but mainly by reducing the sound in the middle frequency range and the high frequency range. It dealt with noise.
Nonwoven fabric is a fabric made by irregularly arranging or entwining natural or synthetic fibers with an adhesive, heat and pressure, and sewing, and is porous with a high porosity and continuous voids. It is a material. Generally, when the thickness of a porous sound absorbing material becomes thin, it becomes difficult to absorb sound in a low frequency range. So far, as sound absorbing materials, those having a basis weight of 0.1 to 20 g / m ² (Patent Document 1) and those having a thickness of 0.5 mm or more are essential (Patent Document 2) have been reported. ..

JP-A-2010-248666 Japanese Unexamined Patent Publication No. 2008-89620 Japanese Unexamined Patent Publication No. 10-168648

An object of the present invention is to provide a sound absorbing body which is thin and has a high sound absorbing coefficient.

The present invention provides the following sound absorbers:
1. 1. A sound absorbing body including a non-woven fabric or a laminated body of non-woven fabric.
The non-woven fabric or the laminate of the non-woven fabric is composed of fibers having an average fiber diameter of less than 3,000 nm.
The thickness of the non-woven fabric or the laminate of the non-woven fabric is less than 10 mm.
The nonwoven fabric or bulk density of the laminate of the nonwoven fabric is smaller than larger and 2,000 kg / m ³ from 50 kg / m ^3,
The sound absorber, wherein the fiber comprises a high density filler, and the high density filler has a higher true density than the fiber.
2. The sound absorbing body according to the above item 1, wherein the fibers constituting the non-woven fabric or the laminated body of the non-woven fabric are fibers formed of a synthetic resin and / or an elastomer.
3. 3. The sound absorbing body according to the second item, wherein the synthetic resin is a thermoplastic resin.
4. The thermoplastic resin is polypropylene, polyacrylonitrile, polyvinylidene fluoride, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, polyamide, polyester, polycarbonate, polyetherimide, polyarylene oxide, thermoplastic polyimide, polyamide. The sound absorber according to the above item 3, which is selected from the group consisting of imide, polybutylene terephthalate, polyethylene terephthalate, polyethylene, acrylonitrile butadiene styrene, and polyurethane.
5. The sound absorbing body according to any one of the above 2 to 4, wherein the elastomer is a thermoplastic elastomer.
6. The sound absorbing body according to the above item 5, wherein the thermoplastic elastomer is a thermoplastic styrene (TPS) elastomer.
7. The thermoplastic styrene elastomers are styrene / butadiene / styrene (SBS), styrene / butadiene / butylene / styrene (SBBS), styrene / isoprene / styrene (SIS) and styrene / butadiene / isoprene / styrene (SBIS), styrene / ethylene. The sound absorber according to item 6 above, which is a copolymer selected from the group consisting of block copolymers of / butylene / styrene (SEBS) and blends of these copolymers.
8. The sound absorber according to item 6 or 7, wherein the thermoplastic styrene elastomer is a styrene / ethylene / butylene / styrene (SEBS) copolymer.
9. The sound absorbing body according to any one of 1 to 8 above, wherein the volume fraction of the high-density filler with respect to the total volume of the fibers constituting the non-woven fabric or the laminated body of the non-woven fabric is larger than 1 volume%.
10. 9. The sound absorbing body according to item 9, wherein the volume fraction of the high-density filler with respect to the total volume of the fibers constituting the non-woven fabric or the laminated body of the non-woven fabric is larger than 2% by volume.
11. The sound absorbing body according to any one of 1 to 10 above, wherein the high-density filler has a density higher than 2,000 kg / m ^3.
12. The sound absorbing body according to any one of 1 to 11 above, wherein the shape of the high-density filler is particulate, lumpy, or fibrous.
13. The sound absorbing body according to the above item 12, wherein the average particle size or the average fiber diameter of the high-density filler is smaller than the average fiber diameter of the non-woven fabric or the fibers constituting the laminate of the non-woven fabric.
14. The sound absorbing body according to any one of 1 to 13 above, wherein the high-density filler contains a metal or a metal derivative.
15. The metal of the metal or the metal derivative is gold, tungsten, lead, silver, bismuth, copper, cobalt, nickel, formium, tin, indium, manganese, chromium, zinc, neodymium, iron, cerium, zirconium, ittrium, titanium, The sound absorbing body according to the above item 14, which is selected from the group consisting of aluminum and a mixture of these metals.
16. The sound absorbing body according to the above 14 or 15, wherein the metal derivative is a metal oxide.
17. The metal oxides are Bi ₂ O ₃ , Ho ₂ O ₃ , Nd ₂ O ₃ , WO ₃ , CeO ₂ , In ₂ O ₃ , SnO ₂ , SnO ₂ , CuO, ZnO, CoO, Fe ₂ O ₃ , Y. Item 16. The sound absorber according to the above item 16, which is selected from the group consisting of ₂ O ₃ , Mn ₃ O ₄ , TiO ₂ , Al ₂ O _{3 and a mixture of metal oxides thereof.}
18. The sound absorbing body according to any one of 1 to 17, wherein the high-density filler is a high-density filler in which at least a part is modified with a surface modifier.
19. The sound absorber according to item 18, wherein the surface modifier is selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, and a mixture thereof.

20. The sound absorbing body according to any one of 1 to 19 above, wherein the sound absorbing peak is less than 3,000 Hz.
21. The sound absorbing body according to any one of 1 to 20 above, wherein the vertically incident sound absorbing coefficient is 0.2 or more.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a thin sound absorbing body that exhibits a sufficient sound absorbing effect in a wide frequency range from a low frequency range to a high frequency range, particularly in a low frequency range. The sound absorber of the present invention, which can be provided in building materials (for example, houses, factories, acoustic facilities), automobiles, tires, electric products, etc., can effectively absorb sound waves.

In this description, all percentages shown are mass percent unless otherwise stated otherwise.
Furthermore, the term "phr" means, within the meaning of this patent application, parts by mass of elastomer, both thermoplastic and non-thermoplastic.
Furthermore, the range of values indicated by the expression "between a and b" all indicate the range of values from greater than a to less than b (ie excluding the endpoints a and b). On the other hand, the interval between the values indicated by the expression "a to b" means the range of values from a to b (that is, including the strict end points a and b).
Further, in the present specification, the term "nonwoven fabric" simply refers to a single non-woven fabric that is not laminated.

1. 1. Raw materials for fibers constituting the non-woven fabric or the laminate of the non-woven fabric The raw materials for the fibers constituting the non-woven fabric or the laminate of the non-woven fabric of the present invention are not particularly limited, but synthetic resins and / or elastomers are preferable. The synthetic resin and / or elastomer is not particularly limited as long as it can form a non-woven fabric or a laminate of non-woven fabrics.

As the synthetic resin, a thermoplastic resin is preferable.
1.1. Thermoplastic resin Examples of the thermoplastic resin include polypropylene, polyacrylonitrile, polyvinylidene fluoride, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone, polyamide, polyester, polycarbonate, polyetherimide, and polyarylene. Examples thereof include oxide, thermoplastic polyimide, polyamideimide, polybutylene terephthalate, polyethylene terephthalate, polyethylene, acrylonitrile butadiene styrene, and polyurethane. These thermoplastic resins may be used alone or in combination of two or more. Of these, polyethylene, polypropylene, polyacrylonitrile, polyvinylidene chloride, and polyurethane are preferable. In particular, polyacrylonitrile or polyurethane is preferred.
The mass average molecular weight of the thermoplastic resin is preferably 4,000 to 3,000,000 g / mol and preferably 30,000 to 500,000 g / mol from the viewpoint of forming a non-woven fabric. The mass average molecular weight can be measured by a known method, for example, using gel permeation chromatography (GPC).

As the elastomer, a thermoplastic elastomer is preferable.
1.2. Thermoplastic Elastomer (TPE) Thermoplastic Elastomer (abbreviated as "TPE") has a structural intermediate between the thermoplastic polymer and the elastomer. These are block copolymers composed of hard thermoplastic resin blocks that are bonded via flexible elastomer blocks.
The thermoplastic elastomer used for the practice of the present invention is a block copolymer. The chemical properties of the thermoplastic block and the elastomer block may be different.

1.2.1. Structure of TPE
The number average molecular weight of TPE (denoted as Mn) is preferably between 30,000 and 500,000 g / mol, more preferably between 40,000 and 400,000 g / mol. If it is lower than the indicated minimum value, there is a risk that it will be difficult to fibrate due to a decrease in the entanglement points of molecular chains and a decrease in cohesive force, and that the mechanical properties will be affected.
Gel permeation chromatography (GPC) quantifies the number average molecular weight (Mn) of TPE elastomers in a known manner. For example, in the case of styrene thermoplastic elastomers, the sample is pre-dissolved in tetrahydrofuran at a concentration of about 1 g / l, then the solution is filtered through a 0.45 μm porous filter and then injected. The device used is the Waters Alliance chromatography line. The elution solvent is tetrahydrofuran, the flow rate is 0.7 ml / min, the system temperature is 35 ° C., and the analysis time is 90 minutes. A set of four consecutive Waters columns, Styragel trade names (HMW7, HMW6E and two HT6E) are used. The injection volume of the solution of the polymer sample is 100 μl. The detector is the Waters 2410 differential refractometer and its associated software for using chromatographic data is the Waters Millennium system. The calculated average molar mass is associated with the calibration curve obtained by the polystyrene standard. Conditions can be adjusted by those skilled in the art.
The value of the TPE polydispersity index PI (Note: PI = Mw / Mn, where Mw mass average molecular weight and Mn number average molecular weight) is preferably less than 3, more preferably less than 2, and even more preferably less than 1.5. Is.

When the glass transition temperature of TPE is mentioned in this patent application, it relates to Tg associated with the elastomer block. The TPE preferably has a glass transition temperature (“Tg”) of preferably 25 ° C. or lower, more preferably 10 ° C. or lower.
As is known, TPE shows two glass transition temperature peaks (Tg, measured according to ASTM D3418), the lowest temperature is associated with the elastomeric portion of TPE and the highest temperature is associated with the thermoplastic portion of TPE. .. Therefore, the flexible block of TPE is defined by the Tg which is below the ambient temperature (25 ° C), and the Tg of the rigid block is higher than 80 ° C.
Being substantially both elastomeric and thermoplastic, TPEs are incompatible enough to retain the properties of the elastomeric blocks or their own properties of the thermoplastic blocks (ie, their respective masses, their respective polarities, or their respective). Must have blocks (which differ as a result of the Tg value).
The TPE may be a copolymer with a small number of blocks (less than 5, typically 2 or 3), in which case these blocks preferably have a high mass greater than 15,000 g / mol. This TPE can be, for example, a diblock copolymer comprising a thermoplastic block and an elastomer block. This TPE is also often a triblock elastomer with two rigid segments joined by flexible segments. Rigid and flexible segments can be positioned linearly or in a stellate or branched arrangement. Typically, each of these segments or blocks often has a minimum of more than 5 base units, generally more than 10 base units (eg, styrene units of styrene / butadiene / styrene block copolymers). Butadiene unit) is included.

The TPE may also contain a number of smaller blocks (more than 30, typically from 50 to 500), in which case these blocks are preferably relatively low mass, eg. It has from 500 to 5000 g / mol; this TPE is still referred to as the multi-block TPE and is a series of elastomeric blocks / thermoplastic blocks.
According to the first variant, the TPE is supplied in linear form. For example, TPE is a diblock copolymer: thermoplastic block / elastomer block. The TPE can also be a Triblock Copolymer: Thermoplastic Block / Elastomer Block / Thermoplastic Block, i.e. the central elastomer block and the two end thermoplastic blocks of each of the two ends of the elastomer block. Similarly, the multi-block TPE can be a linear elastomer block / thermoplastic block series.
According to other variations of the invention, the useful TPE required in the present invention is supplied in a stellate branching form containing at least three branches. For example, in that case, the TPE may consist of a stellate branched elastomer block containing at least three branches and a thermoplastic block located at each end of each branch of the elastomer block. The number of branches of the central elastomer may vary, for example, from 3 to 12, preferably from 3 to 6.
According to another variant of the invention, the TPE is supplied in a branched or dendrimer form. In that case, the TPE may consist of a branched or dendrimer elastomer block and a thermoplastic block located at the end of the branch of the dendrimer elastomer block.

1.2.2. Properties of Elastomer Blocks The TPE elastomer blocks required in the present invention can be any elastomer known to those of skill in the art. The TPE elastomer block preferably has a Tg of less than 25 ° C, preferably less than 10 ° C, more preferably less than 0 ° C, and very preferably less than -10 ° C. Preferably, the Tg of the TPE elastomer block is also higher than -100 ° C.
When the elastomer portion of TPE does not contain ethylene-based unsaturated with respect to the elastomer block containing carbon-based chains, it is called a saturated elastomer block. When the TPE elastomer block contains an ethylene-based unsaturated (ie, carbon-carbon double bond), it is called an unsaturated or diene elastomer block.
Saturated elastomer blocks consist of a polymer sequence obtained by polymerizing at least one (ie, one or more) ethylene monomers, i.e., monomers containing carbon-carbon double bonds. Among the blocks obtained from these ethylene monomers, polyalkylene blocks such as ethylene / propylene or ethylene / butylene random copolymers can be mentioned. These saturated elastomer blocks can also be obtained by hydrogenation of unsaturated elastomer blocks. These saturated elastomer blocks can be aliphatic blocks obtained from the family of polyethers, polyesters or polycarbonates.
In the case of saturated elastomer blocks, this elastomer block of TPE is preferably composed primarily of ethylene units. Primarily, the maximum content of ethylene monomer by mass, preferably greater than 50%, more preferably greater than 75%, even more preferably greater than 85%, based on the total mass of the elastomer block. Is understood to mean.

The C _4- C ₁₄ conjugated diene can be copolymerized with an ethylene monomer. The C _4- C ₁₄ conjugated diene is, in this case, a random copolymer. Preferably, these conjugated dienes are isoprene, butadiene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-1,3-butadiene, 1,3. -Pentadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 1,3-hexadiene , 2-Methyl-1,3-hexadiene, 3-methyl-1,3-hexadiene, 4-methyl-1,3-hexadiene, 5-methyl-1,3-hexadiene, 2,3-dimethyl-1,3 -Hexadiene, 2,4-dimethyl-1,3-hexadiene, 2,5-dimethyl-1,3-hexadiene, 2-neopentylbutadiene, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1-vinyl It is selected from -1,3-cyclohexadiene or a mixture thereof. More preferably, the conjugated diene is isoprene or a mixture containing isoprene.
In the case of unsaturated elastomer blocks, this elastomer block of TPE is preferably composed primarily of a diene elastomer moiety. Primarily, the maximum content of ethylene monomer by mass, preferably greater than 50%, more preferably greater than 75%, even more preferably greater than 85%, based on the total mass of the elastomer block. Is understood to mean. Alternatively, the unsaturated of the unsaturated elastomer block may be derived from a monomer containing double bonds and cyclic type unsaturateds, for example in the case of polynorbornene.

Preferably, the C _4- C ₁₄ conjugated diene can be polymerized or copolymerized to form a diene elastomer block. Preferably, these conjugated dienes are isoprene, butadiene, piperylene, 1-methylbutadiene, 2-methylbutadiene, 2,3-dimethyl-1,3-butadiene, 2,4-dimethyl-1,3-butadiene, 1 , 3-Pentadiene, 2-Methyl-1,3-Pentadiene, 3-Methyl-1,3-Pentadiene, 4-Methyl-1,3-Pentidiene, 2,3-Dimethyl-1,3-Pentadiene, 2,5 -Dimethyl-1,3-pentadiene, 2-methyl-1,4-pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, 2-methyl-1,5-hexadiene, 3-methyl-1 , 3-Hexadiene, 4-methyl-1,3-hexadiene, 5-methyl-1,3-hexadiene, 2,5-dimethyl-1,3-hexadiene, 2,5-dimethyl-2,4-hexadiene, 2 -Neopentyl-1,3-butadiene, 1,3-cyclopentadiene, methylcyclopentadiene, 2-methyl-1,6-heptadiene, 1,3-cyclohexadiene, 1-vinyl-1,3-cyclohexadiene or these Selected from the mixture. More preferably, the conjugated diene is isoprene or butadiene or a mixture containing isoprene and / or butadiene.
According to the variant, the monomers polymerized to form the elastomeric portion of the TPE can be randomly copolymerized with at least one other monomer to form an elastomeric block. According to this modification, the mole fraction of the polymerized monomer other than the ethylene monomer to the total number of units of the elastomeric block must be such that the block retains its elastomeric properties. Advantageously, the mole fraction of the other comonomer can be in the range of 0% to 50%, more preferably 0% to 45%, and even more preferably 0% to 40%.

As an explanation, other monomers that can be copolymerized with the first monomer are ethylene monomers defined above (eg ethylene), diene monomers, and more specifically 4 to 14 carbon atoms as defined above. It may be selected from conjugated diene monomers having up to (eg, butadiene), vinyl aromatic type monomers having 8 to 20 carbon atoms as defined above, or monomers which may include vinyl acetate.
If the comonomer is of the vinyl aromatic type, it is advantageous that the unit portion is in the range of 0% to 50%, preferably 0% to 45%, based on the total number of units of the thermoplastic block. It preferably indicates that it is in the range of 0% to 40%. The above-mentioned styrene monomers, namely methylstyrene, para (tert-butyl) styrene, chlorostyrene, bromostyrene, fluorostyrene or parahydroxystyrene, are particularly suitable as vinyl aromatic compounds. Preferably, the vinyl aromatic type comonomer is styrene.
The elastomeric block can also be a block containing some type of ethylene, diene or styrene monomer as defined above.
Elastomer blocks can also consist of several elastomer blocks as defined above.

1.2.3. Properties of thermoplastic blocks As the definition of thermoplastic blocks, the characteristics of the glass transition temperature (Tg) of the rigid thermoplastic resin block are used. This property is well known to those of skill in the art. This makes it possible to select the industrial processing (conversion) temperature in particular. For amorphous polymers (or polymer blocks), the treatment temperature is chosen to be substantially higher than Tg. In individual cases of semi-crystalline polymers (or polymer blocks), melting points above the glass transition temperature can be observed. In this case, an alternative is the melting point (Mp), which allows the treatment temperature of the polymer (or polymer block) in question to be selected. Therefore, when continuing to mention "Tg (or Mp, if appropriate)", it is necessary to consider this to be the temperature used to select the treatment temperature.
The TPE elastomer required in the present invention preferably comprises one or more thermoplastic blocks having a Tg (or, if appropriate, Mp) of 80 ° C. or higher and formed from polymerized monomers. I'm out. Preferably, the Tg (or Mp, where appropriate) of this thermoplastic block is in the range of 80 ° C to 250 ° C. Preferably, the Tg (or Mp, if appropriate) of this thermoplastic block is preferably from 80 ° C to 200 ° C, more preferably from 80 ° C to 180 ° C.
For TPEs defined for the practice of the present invention, the proportion of thermoplastic blocks is, on the one hand, quantified by the thermoplastic properties that the copolymer must exhibit. Thermoplastic blocks with a Tg (or, where appropriate, Mp) of 80 ° C. or higher are preferably present in sufficient proportion to retain the thermoplastic properties of the elastomers of the invention. The minimum content of thermoplastic blocks with a Tg (or, where appropriate, Mp) of 80 ° C. or higher in the TPE may differ as a function of the copolymer's conditions of use.

Thermoplastic blocks with Tg (or, where appropriate, Mp) above 80 ° C. can be formed from polymerized monomers of various properties; in particular, the thermoplastic blocks are the following blocks or these. May constitute a mixture:
--Polyolefin (polyethylene, polypropylene);
--Polyurethane;
--Polyamide;
--Polyester;
--Polyacetal;
--Polyether (polyethylene oxide, polyphenylene ether);
--Polyphenylene sulfide;
--Polyfluorinated compounds (FEP, PFA, ETFE);
--Polystyrene;
--Polycarbonate;
--Polysulfone;
--Polymethylmethacrylate;
--Polyetherimide;
--Thermoplastic copolymers, such as acrylonitrile / butadiene / styrene (ABS) copolymers. The thermoplastic block is preferably made of polyurethane.

Thermoplastic blocks with Tg (or, where appropriate, Mp) above 80 ° C. can also be obtained from monomers selected from the following compounds and mixtures thereof:
--Acenaphthylene: One of ordinary skill in the art may refer to, for example, the paper Z. Fodor and JP Kennedy, Polymer Bulletin, 1992, 29 (6), 697-705;
--Indene and its derivatives, such as 2-methyl indene, 3-methyl indene, 4-methyl indene, dimethyl indene, 2-phenyl indene, 3-phenyl indene, 4-phenyl indene; 4946899, Inventors Kennedy, Puskas, Kaszas & Hager, JE Puskas, G. Kaszas, JP Kennedy and WG Hager, Journal of Polymer Science, Part A, Polymer Chemistry (1992), 30, 41, and JP Kennedy , N. Meguriya and B. Keszler, Macromolecules (1991), 24 (25), 6572-6577;
--Isoprene, in which case a certain number of trans-1,4-polyisoprene units and cyclized units according to an intramolecular process will be formed; one of ordinary skill in the art will, for example, document G. Kaszas, JE. See also Puskas and P. Kennedy, Applied Polymer Science (1990), 39 (1), 119-144, and JE Puskas, G. Kaszas and JP Kennedy, Macromolecular Science, Chemistry A28 (1991), 65-80. Good.

The thermoplastic block can also be composed of several thermoplastic blocks as defined above.

1.2.4. Examples of TPE For example, TPE is a copolymer whose elastomeric portion is saturated and contains styrene and alkylene blocks. The alkylene block is preferably ethylene, propylene or butylene. More preferably, this TPE elastomer is selected from the following group consisting of linear or stellate branched diblock or triblock copolymers: styrene / ethylene / butylene (SEB), styrene / ethylene / propylene ( SEP), styrene / ethylene / ethylene / propylene (SEEP), styrene / ethylene / butylene / styrene (SEBS), styrene / ethylene / propylene / styrene (SEPS), styrene / ethylene / ethylene / propylene / styrene (SEEPS), styrene / Isobutylene (SIB), Styrene / Styrene / Styrene / Styrene (SIBS) and mixtures of these.
According to another example, the TPE is a copolymer, the elastomeric portion of which is unsaturated and contains a styrene block and a diene block, which diene blocks are particularly isoprene or butadiene blocks. More preferably, this TPE elastomer is selected from the following group consisting of linear or stellate branched diblock or triblock copolymers: styrene / butadiene (SB), styrene / isoprene (SI), styrene. / Butadiden / isoprene (SBI), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / butadiene / isoprene / styrene (SBIS), styrene / ethylene / butylene / styrene (SEBS) and their A mixture of copolymers. More preferably, it is styrene / ethylene / butylene / styrene (SEBS).
For example further, TPE is a linear or stellate branched copolymer whose elastomeric moieties include saturated and unsaturated moieties, such as styrene / butadiene / butylene (SBB), styrene / butadiene / butylene / styrene (SBBS). ) Or a mixture of these copolymers.

Among the multi-block TPEs, copolymers containing random copolymer blocks of ethylene and propylene / polypropylene, polybutadiene / polyurethane (TPU), polyether / polyester (COPE) or polyether / polyamide (PEBA) can be mentioned. As an example of commercially available TPE elastomers, SEPS, sold by Kuraray under the Kraton G product name (eg, G1650, G1651, G1654 and G1730 products) and the Kraton or Septon product name (eg, Septon 2007, Septon 4033 or Septon 8004). SEEPS or SEBS type elastomers, or SIS type elastomers sold by Kuraray under the product name Hybrid 5125 or by Kraton under the product name D1161, or lines sold by Polimeri Europa under the product name Europrene SOLT 166. Examples thereof include the stellate branching SBS type elastomer sold by Kraton under the product name D1184. Elastomers sold by Dexco Polymers under the Vector product name (eg, Vector 4114 or Vector 8508) may also be mentioned. Among the multi-block TPEs, Vistamaxx TPE sold by Exxon; COPE TPE sold by DSM under the Arnitel name, DuPont under the Hytrel name, or Ticona under the Riteflex name; PEBA sold by Arkema under the PEBAX name. TPE; or TPU TPE sold by Sartomer under the product name TPU 7840 or from BASF under the name Elastogran can be mentioned.

1.2.5. TPE Amount If other (non-thermoplastic) elastomers are used in the composition, one or more TPE elastomers make up the main mass fraction; in that case, the elastomer composition. It represents at least 65% by weight, preferably at least 70% by weight, more preferably at least 75% by weight of the combined elastomers present therein. Preferably further, the one or more TPE elastomers represent at least 95% by weight (particularly 100% by weight) of the combined elastomers present in the elastomer composition.
Therefore, the amount of TPE elastomer varies from 65 to 100 phr, preferably from 70 to 100 phr, especially from 75 to 100 phr. Preferably further, the composition comprises 95 to 100 phr of TPE elastomer.

As the raw material for the non-woven fabric, a synthetic resin is preferable, and a thermoplastic resin is more preferable.

2. High-density filler The fibers constituting the non-woven fabric or the laminate of the non-woven fabric of the present invention contain a high-density filler, and this filler has a higher true density than the fibers. The true density of the high density filler at room temperature (eg, 20 ° C.) is preferably ^{higher than 2,000 kg / m 3} (particularly between 2,000 kg / m ³ and 22,500 kg / m ³ ), more preferably 3,000. higher than kg / m ³ (in particular, between 3,000 kg / m ³ and 20,000kg / m ^3).

Such high density fillers are well known to experts in non-woven fabric technology. These fillers have been attempted to improve the cutting resistance of the fibers forming the non-woven fabric (particularly, Patent Document 3).

The content of the high density filler is preferably greater than 1% by volume (particularly between 1% by volume and 70% by volume) with respect to the total volume of the non-woven fabric or fibers constituting the laminate of the non-woven fabric. More preferably, it is greater than 2% by volume (particularly between 2% and 50% by volume), and even more preferably greater than 3% by volume (especially between 3% and 30% by volume). The above minimum value is for obtaining more effective efficacy, while the recommended maximum value is for considering that it is necessary to retain the shape of the fibers constituting the non-woven fabric or the laminate of the non-woven fabric. is there. When the fiber constituting the non-woven fabric or the laminate of the non-woven fabric is composed of a raw material (for example, a synthetic resin and / or an elastomer) of the fiber and a high-density filler, the content of the high-density filler is the fiber, the fiber thereof. It can be calculated from each true density of the raw material of the fiber and the high-density filler (for example, the true density obtained from the true density measurement method according to JIS K 7112: 1980). If the high-density filler is surface-treated with a surface modifier, or if the fiber contains other additives, the fiber, the raw material for the fiber, the high-density filler, the surface modifier or the additive thereof. It can be calculated from each mass (for example, each mass obtained by the thermal weight measurement method according to JIS K 7120: 1987) and each true density.

The shape of the high-density filler is not particularly limited, but a particulate, agglomerate (that is, agglomerate), or fibrous one is preferably used.

For example, when the high-density filler is in the form of particles or lumps, it is preferably by a scanning electron microscope (SEM), a transmission electron microscope (TEM), or a dynamic light scattering method, preferably JIS Z 8828: 2013, ISO. According to the dynamic light scattering method measured according to 13321, it is preferable that the average particle size (that is, the volume average particle size) is smaller than the average fiber diameter of the fibers constituting the non-woven fabric or the laminate of the non-woven fabric.
For example, when the high-density filler is fibrous, the average fiber diameter (that is, the number average fiber diameter) measured by a scanning electron microscope (SEM) or a transmission electron microscope (TEM) is the non-woven fabric or the non-woven fabric. It is preferably smaller than the average fiber diameter of the fibers constituting the laminate.
These reasons are such that the high-density filler enters the fibers constituting the non-woven fabric or the laminate of the non-woven fabric, and the high-density filler in the fibers constituting the laminate of the non-woven fabric or the non-woven fabric. This is because the distribution tends to be more uniform, and the high-density filler is less likely to fall off from the fibers constituting the non-woven fabric or the laminate of the non-woven fabric.

In a preferred embodiment, the average particle size or average fiber diameter of the high density filler is nanosize (1 nm or more and less than 1000 nm). More preferably, it is 1 nm or more and less than 500 nm, and more preferably 1 nm or more and less than 200 nm.

In another preferred embodiment, the ratio of the average particle size or average fiber diameter of the high density filler to the average fiber diameter of the non-woven fabric or the fibers constituting the laminate of the non-woven fabric is less than 0.5 (particularly 0.005). Between 0.5), more preferably less than 0.3 (especially between 0.01 and 0.3), and even more preferably less than 0.2 (especially between 0.02 and 0.2).

In another preferred embodiment, the high density filler may also use high density hollow particles, hollow fibers, or beads.

The high density filler preferably contains a metal or a metal derivative, and more preferably consists of a metal or a metal derivative.

The metal of the metal or metal derivative is osminium, iridium, renium, platinum, gold, tungsten, tantalum, hafnium, lead, silver, molybdenum, bismuth, copper, cobalt, nickel, holmium, niobium, tin, samarium, indium, manganese. , Chromium, zinc, neodymium, iron, cerium, zirconium, lantern, ittium, titanium, barium, aluminum, strontium. Preferably, gold, tungsten, lead, silver, bismuth, copper, cobalt, nickel, holmium, tin, indium, manganese, chromium, zinc, neodymium, iron, cerium, zirconium, ittrium, titanium, aluminum and mixtures of these metals. Selected from the group consisting of.

The metal derivatives are preferably metal sulfates, carbonates, sulfides, oxides, chlorides (eg, iron chloride), hydroxides (eg, iron hydroxide, phosphate phosphite), and / or alloys. It consists of (eg, stainless steel, duralmin, brass, bronze), especially oxides.

The metal and / or metal derivative, in particular the metal oxide, is preferably selected from oxides having ^{a density greater than 3,000 kg / m 3.} Particularly preferred examples of metal oxides are Bi ₂ O ₃ , Ho ₂ O ₃ , Nd ₂ O ₃ , WO ₃ , CeO ₂ , In ₂ O ₃ · SnO ₂ , SnO ₂ , CuO, ZnO, CoO. , Fe ₂ O ₃ (α and / also), Y ₂ O ₃ , Mn ₃ O ₄ , TiO ₂ , Al ₂ O ₃ and metal oxides selected from the group consisting of mixtures of such oxides. it can.

The metals and / or metal derivatives (particularly metal oxides) are well known, for example, Nakalai Tesque, Toho Zinc, Nihon Kagaku Sangyo, Kanto Kagaku, CI Kazei, Taiyo Koko, Sigma-Aldrich. And commercially available from American Elements.

In a preferred embodiment, the metal derivative is a metal oxide of NanoTek (Nanophase Technologies) (more preferably Bi ₂ O ₃ , Ho ₂ O ₃ , Nd ₂ O ₃ , CeO ₂ , In ₂ O ₃ · SnO ₂ , SnO ₂ , CuO, ZnO, CoO, Fe ₂ O ₃ (α and / also), Y ₂ O ₃ , Mn ₃ O ₄ , TiO ₂ , Al ₂ O ₃ and a mixture of such oxides. The metal oxide of choice). This is because the dispersibility of the metal derivative is improved by NanoTek technology, and higher filling is possible in the fibers constituting the non-woven fabric or the laminate of the non-woven fabric.

In another preferred embodiment, the high density filler is a high density filler at least partially modified with a surface modifier. More preferably, the surface modifier is selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone and mixtures thereof. This is because the surface modifier prevents the high-density filler from excessively agglomerating when producing the fibers constituting the non-woven fabric or the laminate of the non-woven fabric, and can have a predetermined size.

3. 3. Additives The fibers constituting the non-woven fabric or the laminate of the non-woven fabric of the present invention may contain any additives, such as antioxidants, lubricants, pigments, and fillers other than the high-density filler, as long as the object of the present invention is not impaired. A crystal nucleating agent may be included. Its content may be, for example, 0.1 to 50% by mass with respect to the total amount of fibers constituting the non-woven fabric or the laminate of the non-woven fabric. However, it is preferable that no additive is contained.

4. Manufacturing Method The fibers and the non-woven fabric constituting the non-woven fabric or the laminate of the non-woven fabric of the present invention can be manufactured by, for example, the electron spinning method described below. The electrospinning method, also called an electrospinning method, an electrostatic spinning method, or an electrospray method, applies a high voltage to a spinning solution and fibers it in the process of discharging the solution to a collector charged with an earth or a sign opposite to that of the spinning solution. The method. Spinning at room temperature is possible, fibers can be produced relatively easily, and the fiber diameter can be controlled over a wide range. It also has the advantage that many polymers can be used. The fibers and the non-woven fabric constituting the non-woven fabric or the laminate of the non-woven fabric of the present invention can also be produced by the composite melt spinning method and the melt blow method.

The spinning solution can be prepared by adding the raw material of the fiber constituting the non-woven fabric or the laminate of the non-woven fabric to the high-density filler dispersion, and then heating and / or stirring as necessary. The heating temperature and stirring time can be appropriately determined by those skilled in the art. For example, stirring may be performed at 20 to 100 ° C. for 1 hour to 1 week.
The high-density filler dispersion can be prepared by adding the high-density filler to the solvent and then heating, stirring and / or ultrasonically dispersing, if necessary. The heating temperature, stirring time and ultrasonic dispersion time can be appropriately determined by those skilled in the art. For example, stirring and ultrasonic dispersion may be performed at 20 to 100 ° C. for 1 hour to 1 week.
The solvent is not particularly limited as long as it can dissolve the raw material of the fiber constituting the non-woven fabric or the laminate of the non-woven fabric, and can evaporate at the stage of spinning to form the fiber. For example, acetone, chloroform, ethanol, 2-propanol, methanol, toluene, tetrahydrofuran, water, benzene, benzyl alcohol, 1,4-dioxane, 1-propanol, dichloromethane, carbon tetrachloride, cyclohexane, cyclohexanone, phenol, pyridine, trichloroethane, Acetic acid, formic acid, hexafluoro-2-propanol, hexafluoroacetone, N, N-dimethylformamide (DMF), N, N-dimethylacetamide, acetonitrile, N-methyl-2-pyrrolidinone, N-methylmorpholin-N-oxide , 1,3-Dioxolane, methylethylketone, and a mixed solvent of the above solvents. One type may be used alone, or two or more types may be used in combination. Of these, N, N-dimethylformamide is preferable from the viewpoint of handleability.
The concentration of the raw material of the fiber constituting the non-woven fabric or the laminate of the non-woven fabric with respect to the spinning solution is preferably 0.1 to 50% by mass, more preferably 5 to 20% by mass.

The applied voltage is usually 5 to 50 kV. The discharge pressure is usually 0.001 to 0.1 MPa. Vacuum drying may be performed to remove the solvent from the obtained non-woven fabric.

5. Physical Properties The average fiber diameter (Fiber diameter, that is, the number average fiber diameter) of the fibers constituting the non-woven fabric or the laminate of the non-woven fabric of the present invention is less than 3000 nm. Pore diameter, maze (Tortuosity: indicates how intricate the air path is to the sample thickness, the ratio of the length of the air path to the sample thickness) increases, and the fiber surface area increases. As a result, the fibers are vibrated by sound waves due to the decrease in fiber rigidity, energy loss (friction between air and fibers) increases, and as a result, the fiber diameter is required to be less than 3000 nm in order to increase the sound absorption coefficient. Be done. For the same reason, stable fiber diameter, and to maintain the rigidity of a given fiber, it is preferably larger than 100 nm and smaller than 3000 nm, more preferably 300 to 2000 nm, and even more preferably 400 to 1200 nm. In this specification, the average diameter of 100 or more fibers is referred to as an average fiber diameter. The average fiber diameter is, for example, 3. When a non-woven fabric is produced by the electron spinning method shown in the production method, it can be adjusted by its spinning conditions (solution discharge pressure, applied voltage, humidity, etc.), viscosity of spinning solution, boiling point of solvent, electrical conductivity and the like.
The obtained non-woven fabric may be laminated to form a laminated body. The number of laminated fabrics may be such that the thickness of the non-woven fabric after lamination is less than 10 mm.
The non-woven fabric before and after laminating may be compressed (pressed). It is preferable to compress the laminate. Compression can be performed under heating and / or pressurizing conditions, for example using a hot press. A person skilled in the art can appropriately set the temperature and pressure at this time in consideration of the thermal properties of the non-woven fabric raw material and the like.
The thickness after compression may be set to be less than 10 mm, but is preferably 1 mm or more and less than 10 mm, more preferably 1.5 to 7.5 mm, and even more preferably 2 to 5 mm. When the thickness is in such a range, it is preferable in that a thin film can be formed while maintaining sound absorption.

Bulk density (Bulk Density), whether or not as a laminate, also with or without compression, greater than 50kg / m ³ 2,000kg / m ³ less. Is preferably smaller than the larger up to 1,600 kg / m ³ from 60 kg / m ^3, more preferably 70~1,200kg / m ^3, more preferably 80~800kg / m ^3. When the bulk density is in such a range, it indicates the difficulty of air flow in the porous material, which is obtained by measuring the pressure difference at 0.5 mm / s according to the unit thickness flow resistivity (ISO9053). In relation to the physical property value), it is preferable to show a sufficient sound absorption effect even in a low frequency range. When compressing the non-woven fabric or the laminate of the non-woven fabric, the bulk density can be adjusted by the compressibility of the non-woven fabric or the laminate of the non-woven fabric of the present invention.

The peak of sound absorption of the sound absorber of the present invention is preferably less than 3000 Hz in order to exhibit a sufficient sound absorption effect even in a low frequency range.

The sound absorption coefficient of the sound absorber of the present invention is preferably at least 0.2. More preferably, it is 0.3 or more. More preferably, it is 0.4 or more. Particularly preferably, it is 0.5 or more.

The vibration space is the thickness of the air layer (nonwoven fabric or non-woven fabric laminate) provided between the non-woven fabric or non-woven fabric laminate and the ground plane when the non-woven fabric or non-woven fabric laminate of the present invention is attached to the ground plane. It is a physical property value representing (distance between the ground plane and the ground plane). A preferred embodiment of the present invention is the sound absorbing body of the present invention having no vibration space. This is because the sound absorbing body becomes compact and practical because there is no vibration space. Another preferred embodiment of the present invention is the sound absorbing body of the present invention provided with a vibration space. This is because the provision of a vibration space effectively exhibits a sufficient sound absorption effect in the low frequency range.

6. Applications The sound absorber of the present invention can be applied to building materials (for example, houses, factories, acoustic facilities), automobiles, tires, electric appliances, and the like.

1. 1. Preparation of sound absorber sample Al ₂ O ₃ particles (Cat.No: 01176-13, average particle size = 31 nm, aluminum oxide NanoTek, Kanto Kagaku) and Ag particles (product number: 576832-5G, average) as high-density fillers A silver nanopowder having a particle size <100 nm and surface-modified with polyvinylpyrrolidone, Sigma-Aldrich) was used.
Each high-density filler is placed in N, N-dimethylformamide (DMF, Kanto Kagaku), stirred at room temperature for about 30 minutes, and then ultrasonically dispersed (ultrasonic cleaner: Branson 5510, Branson). A high-density filler dispersion was obtained.
Polyacrylonitrile (PAN, Mw = 150,000 g / mol, density: 1184 kg / m ³ , Sigma-Aldrich) was added to each of the obtained high-density filler dispersions at an arbitrary concentration, and the temperature was 60 ° C. for about 1 day. After stirring, each spinning solution containing each high-density filler was prepared by further stirring with Mix-Rotar (Mix-Rotar VMR-5, AS ONE Corporation) at room temperature for 1 day or longer. The solution concentration was 12% by mass for Control 1, Comparative Example 1 and Example 1, and 15% by mass for Control 2, Comparative Example 2 and Example 2. For controls 1 and 2, spinning solutions were prepared without the respective high density fillers.
The obtained spinning solution was set in an electrospinning apparatus, and electrospinning was performed at a discharge pressure of 0.003 MPa and an applied voltage of 20 to 25 kV to obtain a non-woven fabric. Electrospinning was performed in an environment of 20 to 30 ° C. and a humidity of 20 to 40%. The obtained non-woven fabric was vacuum dried for 24 hours to remove the solvent. The pressed non-woven fabric thus obtained was used as a sample for measurement.
The press treatment was carried out using a tabletop hot press at room temperature and 20 kPa using a spacer having a thickness of 3 mm. The samples of each example were measured to have a mass corresponding to a 3.0 mm thick sample from the porosity of each control sample having the same fiber diameter (600 nm and 1100 nm, respectively). A 3.0 mm thick sample of fibers containing a density filler was molded to give a non-woven fabric with the same porosity as each control sample. Specifically, the non-woven fabric before the press treatment is cut out, weighed, stacked, and pressed according to the diameter of the vertical incident tube used for measuring the vertical incident sound absorption coefficient and the sound absorption peak of 29 mm. A sample was obtained. Controls 1 and 2 and Comparative Examples 1 and 2 were not pressed. The thickness of the sample was measured with a caliper. _{In Comparative Example 1 and Example 1, the filling amount of Al 2} O ₃ particles with respect to the total volume of polyacrylonitrile of the fibers constituting the sample non-woven fabric was 14.0% by volume, and in Comparative Example 2 and Example 2. The filling amount of Ag particles with respect to the total volume of the fibers constituting the non-woven fabric in the sample was 3.3% by volume. The filling amount (volume fraction) of these high-density fillers was calculated from the mass and true density of polyacrylonitrile, which is a raw material of fibers constituting the non-woven fabric in the spinning solution, and the high-density filler. This is because the high-density filler was not precipitated but dispersed in the spinning solutions of Comparative Examples and Examples. That is, the ratio of the mass (volume) of the high-density filler to the total mass (volume) of the polyacrylonitrile and the high-density filler in the spinning solution is the mass of the high-density filler to the total volume of the fibers constituting the non-woven fabric. This is because it is considered to be equivalent to the rate (volume fraction).

2. Measurement (1) Fiber diameter
Observe the diameter of 100 or more fibers per sample using a scanning electron microscope (Shimadzu Corporation, SS-550), and use the image analysis software ImageJ (National Institute of Public Health) from the obtained SEM images. The average fiber diameter and fiber diameter distribution were obtained.
(2) Bulk Density
The sample was cut into a measurable shape (cylinder or rectangular parallelepiped), the dimensions were measured, the mass was measured with an electronic balance, and the mass was divided by the volume to obtain the bulk density.
(3) True Density
The true density was obtained by measuring the sample mass (Mair, Mwater) in air and water and using the following formula according to Archimedes' principle.
(True density) = Mair / (Mair-Mwater) × (ρ0-d) + d
Here, ρ0 is the density of water and d is the density of air.
(4) Porosity
From the above, it was calculated from the obtained bulk density (ρbulk) and true density (ρtrue) by the following formula.
(Porosity) = 1-ρbulk / ρtrue
(5) Vertically incident sound absorption coefficient and peak of sound absorption
Using an acoustic impedance tube (Bruel & Kjaer, type 4206), the vertical incident sound absorption coefficient and sound absorption peak were calculated by the transfer function method specified in ISO 10534-2. The sample was fixed to the back wall with double-sided tape without vibration space.

3. 3. Results The measurement results are shown in Tables 1 and 2.

Claims (10)

A sound absorbing body including a non-woven fabric or a laminated body of non-woven fabric.
The non-woven fabric or the laminate of the non-woven fabric is composed of fibers having an average fiber diameter of less than 3,000 nm.
The thickness of the non-woven fabric or the laminate of the non-woven fabric is less than 10 mm.
The nonwoven fabric or bulk density of the laminate of the nonwoven fabric is smaller than larger and 2,000 kg / m ³ from 50 kg / m ^3,
The fibers, encloses a high density filler, and
The sound absorber, wherein the high-density filler has a higher true density than the fibers. The sound absorbing body according to claim 1, wherein the fibers constituting the non-woven fabric or the laminated body of the non-woven fabric are fibers formed of a synthetic resin and / or an elastomer. The sound absorbing body according to claim 2 , wherein the elastomer is a thermoplastic elastomer. The sound absorbing body according to any one of claims 1 to 3, wherein the volume fraction of the high-density filler with respect to the total volume of the fibers constituting the non-woven fabric or the laminated body of the non-woven fabric is larger than 1 volume%. The sound absorber according to any one of claims 1 to 4, wherein the high-density filler has a ^{density higher than 2,000 kg / m 3.} The sound absorbing body according to any one of claims 1 to 5, wherein the shape of the high-density filler is particulate, lumpy, or fibrous. The sound absorber according to any one of claims 1 to 6, wherein the high-density filler contains a metal or a metal derivative. The sound absorbing body according to any one of claims 1 to 7, wherein the high-density filler is a high-density filler at least partially modified with a surface modifier. The sound absorbing body according to any one of claims 1 to 8, wherein the sound absorbing peak is less than 3,000 Hz. The sound absorbing body according to any one of claims 1 to 9, wherein the vertically incident sound absorbing coefficient is 0.2 or more.