JPWO2017170653A1 - Sound absorber - Google Patents

Abstract

A sound absorber including a non-woven fabric or a laminate of non-woven fabric, wherein the non-woven fabric or laminate of non-woven fabric is made of fibers having an average fiber diameter of less than 3,000 nm, and the thickness of the non-woven fabric or laminate of non-woven fabric is less than 10 mm The bulk density of the nonwoven fabric or nonwoven fabric laminate is greater than 50 kg / m3 and less than 2000 kg / m3, the fibers contain a high-density filler, and the high-density filler Has a higher true density than the fibers.

Description

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

Noise can cause psychological discomfort to a person, causing irritability and stress, and causing diseases such as headaches and hearing loss. 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 high frequency range. It dealt with noise.
Non-woven fabrics are fabrics made by irregularly arranging or tangling natural or synthetic fibers with adhesives, heat and pressure, and sewing, and are porous with high porosity and continuous voids. Material. In general, when the thickness of the porous sound absorbing material is reduced, it is difficult to absorb sound in a low frequency range. So far, as the sound absorbing material, those having a basis weight of 0.1 to 20 g / m ² (Patent Document 1) and those that are essential to have a thickness of 0.5 mm or more (Patent Document 2) have been reported. .

JP 2010-248666 A JP 2008-89620 A Japanese Patent Laid-Open No. 10-168648

  An object of the present invention is to provide a thin sound absorber having a high sound absorption coefficient.

According to the present invention, the following sound absorber is provided:
1. A sound absorber including a nonwoven fabric or a laminate of nonwoven fabric,
The nonwoven fabric or a laminate of nonwoven fabrics consists of fibers having an average fiber diameter of less than 3,000 nm,
The nonwoven fabric or the laminate of the nonwoven fabric has a thickness of 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 includes a high density filler, and the high density filler has a higher true density than the fiber.
2. 2. The sound absorber according to claim 1, wherein the nonwoven fabric or the fibers constituting the nonwoven fabric laminate is a fiber formed of a synthetic resin and / or an elastomer.
3. The sound absorber according to the above item 2, 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 4. The sound absorber according to 3 above, selected from the group consisting of imide, polybutylene terephthalate, polyethylene terephthalate, polyethylene, acrylonitrile butadiene styrene, and polyurethane.
5. 5. The sound absorber according to any one of 2 to 4, wherein the elastomer is a thermoplastic elastomer.
6). 6. The sound absorber according to claim 5, wherein the thermoplastic elastomer is a thermoplastic styrene (TPS) elastomer.
7). The thermoplastic styrene elastomer is styrene / butadiene / styrene (SBS), styrene / butadiene / butylene / styrene (SBBS), styrene / isoprene / styrene (SIS) and styrene / butadiene / isoprene / styrene (SBIS), styrene / ethylene. 7. The sound absorber according to the above 6, 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 6 or 7, wherein the thermoplastic styrene elastomer is a styrene / ethylene / butylene / styrene (SEBS) copolymer.
9. 9. The sound absorber according to any one of 1 to 8, wherein a volume fraction of the high-density filler with respect to a total volume of fibers constituting the nonwoven fabric or a laminate of nonwoven fabrics is greater than 1% by volume.
10. 10. The sound absorber according to claim 9, wherein a volume fraction of the high-density filler with respect to a total volume of fibers constituting the nonwoven fabric or a laminate of nonwoven fabrics is greater than 2% by volume.
11. The sound absorber according to any one of 1 to 10, wherein the high-density filler has a density higher than 2,000 kg / m ³ .
12 The sound absorber according to any one of 1 to 11 above, wherein a shape of the high-density filler is particulate, lump, or fibrous.
13. 13. The sound absorber according to claim 12, wherein an average particle diameter or an average fiber diameter of the high-density filler is smaller than an average fiber diameter of fibers constituting the nonwoven fabric or the nonwoven fabric laminate.
14 The sound absorber according to any one of 1 to 13, wherein the high-density filler includes a metal or a metal derivative.
15. The metal or metal of the metal derivative is gold, tungsten, lead, silver, bismuth, copper, cobalt, nickel, holmium, tin, indium, manganese, chromium, zinc, neodymium, iron, cerium, zirconium, yttrium, titanium, 15. The sound absorber according to the above 14, selected from the group consisting of aluminum and a mixture of these metals.
16. 16. The sound absorber according to the above 14 or 15, wherein the metal derivative is a metal oxide.
17. The metal oxide is 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 17. The sound absorber according to the above 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 these metal oxides.
18. 18. The sound absorber according to any one of 1 to 17, wherein the high-density filler is a high-density filler that is at least partially modified with a surface modifier.
19. 19. The sound absorber according to claim 18, wherein the surface modifier is selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, and a mixture thereof.

20. 20. The sound absorber according to any one of 1 to 19, wherein the sound absorption peak is less than 3,000 Hz.
21. 21. The sound absorber according to any one of 1 to 20, wherein the normal incident sound absorption coefficient is 0.2 or more.

  According to the present invention, it is possible to provide a thin sound absorber 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 that can be provided in building materials (for example, houses, factories, acoustic facilities), automobiles, tires, electrical products, and the like can effectively absorb sound waves.

In this description, all percentages (%) shown are percentages by weight, unless otherwise specified.
Furthermore, the term “phr” means, within the meaning of this patent application, parts by weight per hundred parts of elastomer mixed with 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 endpoints a and b). On the other hand, any interval of values indicated by the expression “a to b” means a range of values from a to b (ie, including strict endpoints a and b).
In addition, in this specification, when the term “nonwoven fabric” is simply used, it refers to a single nonwoven fabric.

1. The raw material of the fiber which comprises the nonwoven fabric or the laminated body of a nonwoven fabric The raw material of the fiber which comprises the nonwoven fabric of this invention or the laminated body of a nonwoven fabric is although it does not specifically limit, A synthetic resin and / or an elastomer are preferable. The synthetic resin and / or elastomer is not particularly limited as long as it can form a nonwoven fabric or a laminate of nonwoven fabrics.

As the synthetic resin, a thermoplastic resin is preferable.
1.1. Thermoplastic resin Examples of thermoplastic resins 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. Among these, polyethylene, polypropylene, polyacrylonitrile, polyvinylidene fluoride, 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 nonwoven 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) A thermoplastic elastomer (abbreviated as “TPE”) has a structural intermediate between the thermoplastic polymer and the elastomer. These are block copolymers composed of rigid thermoplastic blocks that are joined via flexible elastomeric 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. TPE structure
The number average molecular weight (denoted Mn) of TPE 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 becomes difficult to form fibers due to a decrease in the entanglement points of molecular chains and a decrease in cohesive force, and the mechanical properties are affected.
Gel permeation chromatography (GPC) quantifies the number average molecular weight (Mn) of the TPE elastomer in a known manner. For example, in the case of a styrene thermoplastic elastomer, the sample is pre-dissolved in tetrahydrofuran at a concentration of about 1 g / l, and then the solution is injected after being filtered through a filter having a porosity of 0.45 μm. The equipment used is the Waters Alliance chromatography line. The elution solvent is tetrahydrofuran, the flow rate is 0.7 ml / min, the temperature of the system is 35 ° C., and the analysis time is 90 minutes. A series of four Waters columns, Styragel trade names (HMW7, HMW6E and two HT6E) are used. The injection volume of the polymer sample solution is 100 μl. The detector is a Waters 2410 differential refractometer and its associated software for using chromatographic data is a Waters Millennium system. The calculated average molar mass is related to the calibration curve obtained by the polystyrene standard. Conditions can be adjusted by those skilled in the art.
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 It is.

In this patent application, when the glass transition temperature of TPE is mentioned, it relates to the Tg associated with the elastomer block. 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 (measured according to Tg, 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. . Thus, the flexible block of TPE is defined by a Tg that is below ambient temperature (25 ° C.), and the Tg of the rigid block is higher than 80 ° C.
Because they are both substantially elastomeric and thermoplastic, TPEs are sufficiently incompatible to retain their own properties of elastomeric blocks or thermoplastic blocks (i.e., each mass, each polarity, or each Must have different blocks) as a result of the Tg value.
The TPE may be a copolymer having 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. The TPE can be, for example, a diblock copolymer comprising a thermoplastic block and an elastomer block. This TPE is also often a triblock elastomer having two rigid segments joined by a flexible segment. The rigid and flexible segments can be positioned linearly or in a star or branched arrangement. Typically, each of these segments or blocks often has a minimum of more than 5 base units, typically more than 10 base units (e.g., styrene units of a styrene / butadiene / styrene block copolymer). Butadiene unit).

The TPE may also include a number of smaller blocks (greater than 30, typically 50 to 500), in which case these blocks preferably have a relatively low mass, e.g. Having from 500 to 5000 g / mol; this TPE is subsequently referred to as multi-block TPE and is an elastomer block / thermoplastic block series.
According to a first variant, TPE is supplied in a linear form. For example, TPE is diblock copolymer: thermoplastic block / elastomer block. The TPE can also be a triblock copolymer: a thermoplastic block / elastomer block / thermoplastic block, ie a central elastomer block and two terminal thermoplastic blocks at 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 another variant of the invention, the useful TPE required for the invention is supplied in a star-branched form comprising at least three branches. For example, in that case, the TPE may be composed of a star-branched elastomeric block containing at least three branches and a thermoplastic block located at the end of each branch of the elastomeric block. The number of branches in 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 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. Elastomer Block Properties The elastomeric block of TPE required for the present invention can be any elastomer known to those skilled in the art. The elastomeric block of TPE preferably has a Tg of less than 25 ° C, preferably less than 10 ° C, more preferably less than 0 ° C, very preferably less than -10 ° C. Preferably, the Tg of the TPE elastomer block is also higher than -100 ° C.
When the elastomeric part of TPE does not contain ethylenic unsaturation with respect to the elastomeric block containing carbon-based chains, it is called a saturated elastomeric block. When the elastomeric block of TPE contains ethylenic unsaturation (ie, carbon-carbon double bonds), it is referred to as an unsaturated or diene elastomeric block.
A saturated elastomeric block is composed of a polymer sequence obtained by polymerization of at least one (ie, one or more) ethylene monomers, ie, monomers containing carbon-carbon double bonds. Among the blocks obtained from these ethylene monomers, mention may be made of polyalkylene blocks, such as ethylene / propylene or ethylene / butylene random copolymers. These saturated elastomeric blocks can also be obtained by hydrogenation of unsaturated elastomeric blocks. These saturated elastomeric blocks can be aliphatic blocks derived from the polyether, polyester or polycarbonate family.
In the case of saturated elastomer blocks, this elastomer block of TPE is preferably mainly composed of ethylene units. Mainly the largest content by weight of ethylene monomer, preferably more than 50%, more preferably more than 75%, even more preferably more than 85%, by weight relative to the total weight of the elastomeric block Is understood to mean.

C ₄ -C ₁₄ conjugated dienes can be copolymerized with ethylene monomers. 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 comprising isoprene.
In the case of unsaturated elastomeric blocks, this elastomeric block of TPE is preferably mainly composed of a diene elastomer part. Mainly the largest content by weight of ethylene monomer, preferably more than 50%, more preferably more than 75%, even more preferably more than 85%, by weight relative to the total weight of the elastomeric block Is understood to mean. Alternatively, the unsaturation of the unsaturated elastomeric block may be derived from monomers containing double bonds and cyclic type unsaturation, 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-pentadiene, 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-thio Selected from Rohekisajien or mixtures thereof. More preferably, the conjugated diene is isoprene or butadiene or a mixture comprising isoprene and / or butadiene.
According to a variant, the monomer polymerized to form the elastomeric part of the TPE can be randomly copolymerized with at least one other monomer so as to form an elastomeric block. According to this variant, the mole fraction of polymerized monomers other than ethylene monomer relative to the total number of units of the elastomer block must be such that the block retains its elastomer properties. Advantageously, the molar fraction of this other comonomer may range from 0% to 50%, more preferably from 0% to 45%, even more preferably from 0% to 40%.

By way of illustration, this other monomer that can be copolymerized with the first monomer is an ethylene monomer as defined above (e.g. ethylene), a diene monomer, more specifically 4 to 14 carbon atoms as defined above. Conjugated diene monomers having up to (eg butadiene), vinyl aromatic type monomers having from 8 to 20 carbon atoms as defined above, or monomers such that vinyl acetate can be included.
When the comonomer is of vinyl aromatic type, advantageously the unit part is in the range of 0% to 50%, preferably 0% to 45%, relative to the total number of units of the thermoplastic block, more It represents that it is preferably in the range of 0% to 40%. The styrene monomers mentioned above, ie 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 may also be a block comprising several types of ethylene, diene or styrene monomers as defined above.
The elastomeric block may also be composed of several elastomeric blocks as defined above.

1.2.3. Properties of the thermoplastic block The definition of the thermoplastic block is the property of the glass transition temperature (Tg) of the rigid thermoplastic block. This property is well known to those skilled in the art. This makes it possible in particular to select industrial processing (conversion) temperatures. In the case of an amorphous polymer (or polymer block), the processing temperature is chosen to be substantially higher than Tg. In the individual case of a semicrystalline polymer (or polymer block), a melting point higher than the glass transition temperature can be observed. In this case, it is instead the melting point (Mp) that makes it possible to select the processing temperature of the polymer (or polymer block) in question. Therefore, when subsequently referring to “Tg (or Mp if appropriate)”, it is necessary to consider that this is the temperature used to select the processing temperature.
The TPE elastomer required for the present invention preferably comprises one or more thermoplastic blocks formed from polymerized monomers having a Tg (or Mp, where appropriate) of 80 ° C or higher. It is out. Preferably, the Tg (or Mp, where appropriate) of the thermoplastic block is in the range of 80 ° C to 250 ° C. Preferably, the Tg (or Mp, where appropriate) of the thermoplastic block is preferably from 80 ° C to 200 ° C, more preferably from 80 ° C to 180 ° C.
With respect to TPE defined for the practice of the present invention, the proportion of thermoplastic block is determined on the one hand by the thermoplastic properties that the copolymer must exhibit. The thermoplastic block having a Tg (or Mp, if appropriate) of 80 ° C. or higher is preferably present in a proportion sufficient to retain the thermoplastic properties of the elastomers of the present invention. The minimum thermoplastic block content with a Tg (or Mp, where appropriate) greater than 80 ° C. in the TPE may vary as a function of the conditions of use of the copolymer.

Thermoplastic blocks having a Tg (or Mp, where appropriate) greater than 80 ° C. may be formed from polymerized monomers of various properties; in particular, the thermoplastic block may be a block of: A mixture can be composed:
-Polyolefins (polyethylene, polypropylene);
-Polyurethane;
-Polyamides;
-Polyester;
-Polyacetal;
-Polyethers (polyethylene oxide, polyphenylene ether);
-Polyphenylene sulfide;
-Polyfluorinated compounds (FEP, PFA, ETFE);
-Polystyrene;
-Polycarbonate;
-Polysulfone;
-Polymethyl methacrylate;
-Polyetherimide;
-Thermoplastic copolymers, such as acrylonitrile / butadiene / styrene (ABS) copolymers. The thermoplastic block preferably constitutes polyurethane.

Thermoplastic blocks with a Tg (or Mp, where appropriate) greater than 80 ° C. can also be obtained from monomers selected from the following compounds and mixtures thereof:
-Acenaphthylene: the person skilled in the art may refer, for example, to the article Z. Fodor and JP Kennedy, Polymer Bulletin, 1992, 29 (6), 697-705;
Indene and its derivatives, such as 2-methylindene, 3-methylindene, 4-methylindene, dimethylindene, 2-phenylindene, 3-phenylindene, 4-phenylindene; No. 4946899, inventor Kennedy, Puskas, Kaszas & Hager, literature 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;
Resulting in the formation of isoprene, in that case a specific number of trans-1,4-polyisoprene units and units cyclized according to an intramolecular process; the person skilled in the art, for example, documents 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 blocks and alkylene blocks. The alkylene block is preferably ethylene, propylene or butylene. More preferably, the TPE elastomer is selected from the following group consisting of linear or star-branched diblock copolymers 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 / isobutylene / styrene (SIBS) and mixtures of these copolymers.
According to another example, TPE is a copolymer, the elastomer part of which is unsaturated and comprises styrene blocks and diene blocks, these diene blocks being in particular isoprene blocks or butadiene blocks. More preferably, the TPE elastomer is selected from the following group consisting of linear or star-branched diblock copolymers or triblock copolymers: styrene / butadiene (SB), styrene / isoprene (SI), styrene / Butadiene / isoprene (SBI), styrene / butadiene / styrene (SBS), styrene / isoprene / styrene (SIS), styrene / butadiene / isoprene / styrene (SBIS), styrene / ethylene / butylene / styrene (SEBS) and these A mixture of copolymers. More preferred is styrene / ethylene / butylene / styrene (SEBS).
For example, furthermore, TPE is a linear or star-branched copolymer, the elastomer part of which contains a saturated part and an unsaturated part, such as styrene / butadiene / butylene (SBB), styrene / butadiene / butylene / styrene (SBBS). ) Or a mixture of these copolymers.

  Among multiblock TPEs, mention may be made of copolymers comprising random copolymer blocks of ethylene and propylene / polypropylene, polybutadiene / polyurethane (TPU), polyether / polyester (COPE) or polyether / polyamide (PEBA). Examples of commercially available TPE elastomers include SEPS sold by Kraray under the Kraton G product name (e.g. G1650, G1651, G1654 and G1730 products) and Kraton or Septon product names (e.g. Septon 2007, Septon 4033 or Septon 8004), SEEPS or SEBS type elastomers, or SIS type elastomers sold by Kraray under the product name Hybrar 5125 or sold by Kraton under the product name D1161, or wires sold by Polimeri Europa under the product name Europrene SOLT 166 Mention may be made of elastomeric SBS types or star-branched SBS type elastomers sold by Kraton under the product name D1184. Mention may also be made of elastomers sold by Dexco Polymers under the Vector product name (eg Vector 4114 or Vector 8508). Among the multi-block TPEs, Vistamaxx TPE sold by Exxon; COPE TPE sold by DSM under Arnitel name, DuPont under Hytrel name or Ticona under Riteflex name; PEBA sold by Arkema under PEBAX name TPE; or TPU TPE sold by Sartomer under the product name TPU 7840 or BASF under the Elastogran name.

1.2.5. TPE amount If other (non-thermoplastic) elastomers are used in the composition if necessary, one or more TPE elastomers constitute the main mass fraction; in that case, the elastomer composition It represents at least 65%, preferably at least 70%, more preferably at least 75% by weight of the combined elastomers present therein. Preferably still further, the one or more TPE elastomers represent at least 95% (especially 100%) by weight of the combined elastomers present in the elastomer composition.
Accordingly, the amount of TPE elastomer is in a range that varies from 65 to 100 phr, preferably from 70 to 100 phr, in particular from 75 to 100 phr. Preferably still further, the composition comprises 95 to 100 phr of TPE elastomer.

  As the nonwoven material, a synthetic resin is preferable, and a thermoplastic resin is more preferable.

2. High density filler The fiber which comprises the nonwoven fabric of this invention or the laminated body of a nonwoven fabric contains a high density filler, and this filler has a higher true density than the said fiber. The true density of the high density filler at room temperature (eg 20 ° C.) is preferably higher than 2,000 kg / m ³ (especially 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 those skilled in the nonwoven art. These fillers have been tried to improve the cutting resistance of the fibers forming the nonwoven fabric (in particular, Patent Document 3).

  The content of the high-density filler is preferably greater than 1% by volume (particularly between 1% and 70% by volume) with respect to the total volume of the fibers constituting the nonwoven fabric or the laminate of nonwoven fabrics, More preferably, it is greater than 2% by volume (particularly between 2% and 50% by volume), more preferably greater than 3% by volume (particularly between 3% and 30% by volume). The above-mentioned minimum value is for obtaining a more effective effect, while the recommended maximum value is because the shape of the fibers constituting the nonwoven fabric or the laminate of the nonwoven fabric needs to be maintained. is there. The content of the high-density filler is such that when the fibers constituting the nonwoven fabric or the laminate of nonwoven fabrics are composed of the raw material of the fibers (for example, synthetic resin and / or elastomer) and the high-density filler, the fibers, It can be calculated from the true density of the fiber raw material and the high-density filler (for example, the true density determined 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 the fiber contains other additives, the fiber, the raw material of the fiber, the high-density filler, the surface modifier, or the additive Each mass (for example, each mass determined by a thermogravimetric method according to JIS K 7120: 1987) and each true density can be calculated.

Although there is no restriction | limiting in particular about the shape of the said high density filler, A particulate form, a lump shape (namely, aggregate shape), or a fibrous thing is used preferably.

For example, when the high-density filler is in the form of particles or lumps, it is preferably JIS Z 8828: 2013, ISO, by scanning electron microscope (SEM), transmission electron microscope (TEM), or dynamic light scattering method. It is preferable that the average particle diameter (that is, the volume average particle diameter) is smaller than the average fiber diameter of the fibers constituting the nonwoven fabric or the laminate of nonwoven fabrics by the measured dynamic light scattering method according to 13321.
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 nonwoven fabric or the nonwoven fabric. It is preferable that the average fiber diameter of the fibers constituting the laminate is smaller.
The reason for this is that the high-density filler is in the form of entering the fibers constituting the nonwoven fabric or nonwoven fabric laminate, and the high-density filler is contained in the fibers constituting the nonwoven fabric or nonwoven fabric laminate. 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 nonwoven fabric or the laminate of nonwoven fabrics.

As a preferred embodiment, the average particle diameter or the average fiber diameter of the high-density filler is nano-sized (1 nm or more and less than 1000 nm). More preferably, they are 1 nm or more and less than 500 nm, More preferably, they are 1 nm or more and less than 200 nm.

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

In another preferred embodiment, the high-density filler can 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 or metal of the metal derivative is osmium, iridium, rhenium, platinum, gold, tungsten, tantalum, hafnium, lead, silver, molybdenum, bismuth, copper, cobalt, nickel, holmium, niobium, tin, samarium, indium, manganese , Chromium, zinc, neodymium, iron, cerium, zirconium, lanthanum, yttrium, titanium, barium, aluminum, and strontium. Preferably, gold, tungsten, lead, silver, bismuth, copper, cobalt, nickel, holmium, tin, indium, manganese, chromium, zinc, neodymium, iron, cerium, zirconium, yttrium, titanium, aluminum and mixtures of these metals Selected from the group consisting of

  Said metal derivatives are preferably metal sulfates, carbonates, sulfides, oxides, chlorides (eg iron chloride), hydroxides (eg iron hydroxide, hydroxyapatite), and / or alloys (For example, stainless steel, duralumin, brass, bronze), in particular oxides.

Said metals and / or metal derivatives, in particular metal oxides, are preferably selected from oxides with a density higher than 3,000 kg / m ³ . In particular, examples of preferred metal oxides include 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. And metal oxides selected from the group consisting of Fe ₂ O ₃ (α and / or), Y ₂ O ₃ , Mn ₃ O ₄ , TiO ₂ , Al ₂ O ₃ and mixtures of such oxides. it can.

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

In a preferred embodiment, the metal derivative is a metal oxide NanoTek (Nanophase Technologies Corporation) (more _{preferably, Bi 2 O 3, Ho 2} O 3, Nd 2 O 3, CeO 2, In 2 O 3 · SnO 2 From the group consisting of SnO ₂ , CuO, ZnO, CoO, Fe ₂ O ₃ (α and / or), Y ₂ O ₃ , Mn ₃ O ₄ , TiO ₂ , Al ₂ O ₃ and mixtures of such oxides Selected metal oxide). This is because the dispersibility of the metal derivative is improved by NanoTek technology, and higher filling is possible in the fibers constituting the nonwoven fabric or the laminate of nonwoven fabrics.

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

3. Additives In the fibers constituting the nonwoven fabric of the present invention or the laminate of the nonwoven fabric, any additive, for example, an antioxidant, a lubricant, a pigment, a filler other than the high-density filler, within the range not impairing the object of the present invention, A crystal nucleating agent may be included. The content may be, for example, 0.1 to 50% by mass with respect to the total amount of fibers constituting the nonwoven fabric or the laminate of the nonwoven fabric. However, it is preferred not to include any additives.

4). Manufacturing method The fiber and nonwoven fabric which comprise the nonwoven fabric of this invention or the laminated body of a nonwoven fabric can be manufactured, for example by the electron spinning method demonstrated below. Electrospinning, also called electrospinning, electrospinning, or electrospraying, applies a high voltage to the spinning solution and fiberizes it in the process of discharging the solution to a grounded or charged collector opposite to the spinning solution. Is the method. Spinning at room temperature is possible, fibers can be produced relatively easily, and the fiber diameter can be controlled widely. In addition, there is an advantage that many polymers can be used. The fiber and the nonwoven fabric constituting the nonwoven fabric or the laminate of the nonwoven fabric of the present invention can also be produced by a composite melt spinning method or a melt blow method.

The spinning solution can be prepared by adding a raw material of a fiber constituting a nonwoven fabric or a laminate of nonwoven fabrics to the high-density filler dispersion, and then heating and / or stirring as necessary. A person skilled in the art can appropriately determine the heating temperature and the stirring time. 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 ultrasonic dispersion as necessary. A person skilled in the art can appropriately determine the heating temperature, the stirring time, and the ultrasonic dispersion time. 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 nonwoven fabric or the laminate of the nonwoven 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-methylmorpholine-N-oxide 1,3-dioxolane, methyl ethyl ketone, and a mixed solvent of the above solvents. One kind may be used alone, or two or more kinds may be used in combination. Among these, N, N-dimethylformamide is preferable from the viewpoint of handleability.
The concentration of the raw material of the fibers constituting the nonwoven fabric or the nonwoven fabric laminate with respect to the spinning solution is preferably 0.1 to 50 mass%, more preferably 5 to 20 mass%.

  The applied voltage is usually 5 to 50 kV. The discharge pressure is usually 0.001 to 0.1 MPa. You may vacuum-dry in order to remove the said solvent from the obtained nonwoven fabric.

5). Physical Properties The average fiber diameter (Fiber diameter, that is, the number average fiber diameter) of the fibers constituting the nonwoven fabric or nonwoven fabric laminate of the present invention is less than 3000 nm. Hole diameter, maze degree (Tortuosity: how much the air path is relative to the sample thickness, the ratio of the air path length to the sample thickness) increases, and the fiber surface area increases In addition, the fiber is vibrated by sound waves due to the decrease in fiber stiffness and energy loss (friction between air and fiber) increases, and as a result, the fiber diameter must be less than 3000 nm in order to increase the sound absorption coefficient. It is done. In order to maintain the same reason and stable fiber diameter and predetermined fiber rigidity, it is preferably larger than 100 nm and smaller than 3000 nm, more preferably 300 to 2000 nm, and further preferably 400 to 1200 nm. In the present specification, an average diameter of 100 or more fibers is referred to as an average fiber diameter. The average fiber diameter is, for example, 3. When the nonwoven fabric is produced by the electrospinning method shown in the production method, it can be adjusted by the spinning conditions (solution discharge pressure, applied voltage, humidity, etc.), the viscosity of the spinning solution, the boiling point of the solvent, the electrical conductivity and the like.
It is good also as a laminated body by laminating the obtained nonwoven fabric. The number of laminated layers may be such that the thickness (Thickness) of the nonwoven fabric after lamination is less than 10 mm.
The nonwoven fabric before and after lamination may be compressed (pressed). It is preferable to compress the laminate. The compression can be performed under heating and / or pressurization conditions using, for example, a hot press machine. Those skilled in the art can appropriately set the temperature and pressure at this time in consideration of the thermal properties of the nonwoven fabric raw material.
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. It 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 within such a range, the unit thickness flow resistance (Flow thermally: represents the difficulty of air flow in the porous material obtained by measuring the pressure difference at 0.5 mm / s according to ISO9053) In view of the physical property value), it is preferable in order to show a sufficient sound absorption effect even in a low frequency range. In addition, when compressing a nonwoven fabric or the laminated body of a nonwoven fabric, a bulk density can be adjusted with the compression rate to the laminated body of the nonwoven fabric or nonwoven fabric of this invention.

  The sound absorption peak (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 provided between the non-woven fabric or the non-woven fabric laminate and the ground surface when the non-woven fabric or non-woven fabric laminate of the present invention is attached to the ground surface (non-woven fabric or non-woven fabric laminate). Is a physical property value representing the distance between the contact surface and the ground plane. A preferred embodiment of the present invention is the sound absorber of the present invention having no vibration space. This is because the sound absorber is compact and practical due to the absence of vibration space. Another preferred embodiment of the present invention is the sound absorber of the present invention provided with a vibration space. This is because providing a vibration space effectively exhibits a sufficient sound absorption effect in a 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, electrical products, and the like.

1. Preparation of sound absorber samples 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 filler Silver nanopowders with a particle size <100 nm, surface-modified with polyvinylpyrrolidone (Sigma-Aldrich)) were used.
Each high-density filler is placed in N, N-dimethylformamide (DMF, Kanto Kagaku), stirred for about 30 minutes at room temperature, and then subjected to ultrasonic dispersion (ultrasonic cleaner: Branson 5510, Branson) A high density filler dispersion was obtained.
Polyacrylonitrile (PAN, Mw = 150,000g / mol, density: 1184kg / m ³ , Sigma-Aldrich) is added to each of the resulting high-density filler dispersions at an arbitrary concentration, and at 60 ° C for about 1 day. After stirring, each spinning solution containing each high-density filler was prepared by further stirring at room temperature for 1 day or longer with Mix-Rotar (Mix-Rotar VMR-5, ASONE). 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 without each high density filler were made.
The obtained spinning solution was set in an electrospinning apparatus, and non-woven fabric was obtained by performing electrospinning at a discharge pressure of 0.003 MPa and an applied voltage of 20 to 25 kV. Electrospinning was performed in an environment of 20 to 30 ° C. and humidity of 20 to 40%. The obtained nonwoven fabric was vacuum-dried for 24 hours to remove the solvent. The measurement was performed using a pressed non-woven fabric obtained as a sample.
The press treatment was performed using a desktop hot press using a 3 mm thick spacer at room temperature and 20 kPa. For each example sample, a mass corresponding to a 3.0 mm thick sample was calculated from the porosity of each control sample having an equivalent fiber diameter (600 nm and 1100 nm, respectively) and weighed to have that mass. A 3.0 mm thick sample consisting of fibers containing density filler was molded to obtain a nonwoven fabric having the same porosity as each control sample. Specifically, the non-woven fabric before press treatment was cut out, weighed, overlapped, and pressed in accordance with the diameter of the normal incidence tube used for measurement of the normal incidence sound absorption coefficient and the sound absorption peak. 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 relative to the total volume of polyacrylonitrile of the fibers constituting the sample nonwoven fabric was 14.0% by volume, and Comparative Example 2 and Example 2 In addition, the filling amount of Ag particles with respect to the total volume of fibers constituting the nonwoven 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 and the high-density filler that are the raw materials of the fibers constituting the nonwoven fabric in the spinning solution. This is because the high-density filler was not precipitated and dispersed in the spinning solutions of the comparative examples and examples. In other words, the ratio of the mass (volume) of the high-density filler to the mass (volume) of the polyacrylonitrile and the high-density filler in the spinning solution is the mass fraction of the high-density filler relative to the total volume of the fibers constituting the nonwoven fabric. This is because it is considered to be equivalent to the rate (volume fraction).

2. Measurement (1) Fiber diameter
More than 100 fiber diameters per sample were observed using a scanning electron microscope (Shimadzu Corporation, SS-550). From the obtained SEM images, image analysis software ImageJ (National Institutes of Health) was used. The average fiber diameter and fiber diameter distribution were obtained.
(2) Bulk Density
The sample was cut into a measurable shape (a cylinder or a rectangular parallelepiped), and after measuring the dimensions, the mass was measured with an electronic balance, and the bulk density was obtained by dividing the mass by the volume.
(3) True Density
The true density was obtained by measuring the sample mass (Mair, Mwater) in air and water, and using the following formula based on 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) Normal absorption sound absorption coefficient (Sound absorption coefficient) and sound absorption peak (Peak of sound absorption)
Using an acoustic impedance tube (Bruel & Kjaer, Model 4206), the normal incident sound absorption coefficient and sound absorption peak were calculated by the transfer function method defined in ISO 10534-2. The sample was fixed to the back wall with double-sided tape without vibration space.

3. Results Tables 1 and 2 show the measurement results.

Claims (21)

A sound absorber including a nonwoven fabric or a laminate of nonwoven fabric,
The nonwoven fabric or a laminate of nonwoven fabrics consists of fibers having an average fiber diameter of less than 3,000 nm,
The nonwoven fabric or the laminate of the nonwoven fabric has a thickness of 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 includes a high density filler, and the high density filler has a higher true density than the fiber.   The sound absorber according to claim 1, wherein the fibers constituting the nonwoven fabric or the laminate of nonwoven fabrics are fibers formed from a synthetic resin and / or an elastomer.   The sound absorber according to claim 2, wherein the synthetic resin is a thermoplastic resin.   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 claim 3, selected from the group consisting of imide, polybutylene terephthalate, polyethylene terephthalate, polyethylene, acrylonitrile butadiene styrene, and polyurethane.   The sound absorber according to any one of claims 2 to 4, wherein the elastomer is a thermoplastic elastomer.   The sound absorber according to claim 5, wherein the thermoplastic elastomer is a thermoplastic styrene (TPS) elastomer.   The thermoplastic styrene elastomer is 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 claim 6, which is a copolymer selected from the group consisting of block copolymers of / butylene / styrene (SEBS), and blends of these copolymers.   The sound absorber according to claim 6 or 7, wherein the thermoplastic styrene elastomer is a styrene / ethylene / butylene / styrene (SEBS) copolymer. The sound absorber according to any one of claims 1 to 8, wherein a volume fraction of the high-density filler with respect to a total volume of fibers constituting the nonwoven fabric or a laminate of nonwoven fabrics is greater than 1% by volume. The sound absorber according to claim 9, wherein a volume fraction of the high-density filler with respect to a total volume of fibers constituting the nonwoven fabric or a laminate of nonwoven fabrics is greater than 2% by volume. The sound absorber according to any one of claims 1 to 10, wherein the high-density filler has a density higher than 2,000 kg / m ³ . The sound absorber according to any one of claims 1 to 11, wherein a shape of the high-density filler is particulate, lump, or fibrous. The sound absorber according to claim 12, wherein an average particle diameter or an average fiber diameter of the high-density filler is smaller than an average fiber diameter of fibers constituting the nonwoven fabric or the laminate of nonwoven fabrics. The sound absorber according to any one of claims 1 to 13, wherein the high-density filler includes a metal or a metal derivative. The metal or metal of the metal derivative is gold, tungsten, lead, silver, bismuth, copper, cobalt, nickel, holmium, tin, indium, manganese, chromium, zinc, neodymium, iron, cerium, zirconium, yttrium, titanium, The sound absorber according to claim 14, selected from the group consisting of aluminum and a mixture of these metals. The sound absorber according to claim 14 or 15, wherein the metal derivative is a metal oxide. The metal oxide is 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 The sound absorber according to claim 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 these metal oxides. The sound absorber according to any one of claims 1 to 17, wherein the high-density filler is a high-density filler that is at least partially modified with a surface modifier. The sound absorber according to claim 18, wherein the surface modifier is selected from the group consisting of polyethylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, and a mixture thereof.   The sound absorber according to any one of claims 1 to 19, wherein the sound absorption peak is less than 3,000Hz. The sound absorber according to any one of claims 1 to 20, wherein the normal incident sound absorption coefficient is 0.2 or more.