sound-absorbing material

Abstract

The present disclosure pertains to a sound-absorbing material comprising, in the following order, a resin film, a first substrate layer having communication holes, and a second substrate layer having communication holes.

Description

[Technical Field]

[0001] The present invention relates to a sound absorbing material. [Background technology]

[0002] A single-layer sound-absorbing structure made of a melt-blown nonwoven fabric is known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-214957 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of a single layer sound absorbing structure made of nonwoven fabric, the sound absorbing properties are insufficient, especially in the low frequency range.

[0005] The present invention has been made in view of the above circumstances, and has as its object to provide a sound-absorbing material that has excellent sound-absorbing properties in the low frequency range. [Means for solving the problem]

[0006] The present invention provides a sound-absorbing material comprising, in this order, a resin film, a first base material layer having communicating holes, and a second base material layer having communicating holes.

[0007] In one embodiment, the first base material layer and the second base material layer may be a resin foam or a nonwoven fabric.

[0008] In one embodiment, the thickness of the first substrate layer may be less than the thickness of the second substrate layer.

[0009] In one embodiment, the resin film may be made of polyolefin, polyester, or polyamide.

[0010] In one embodiment, the sound-absorbing material may have a metal vapor-deposited layer on at least one surface of the resin film.

[0011] In one embodiment, the sound-absorbing material may further include an adhesive layer between the resin film and the first base material layer and / or between the first base material layer and the second base material layer.

[0012] In one embodiment, the thickness of the sound absorbing material may be 1 to 100 mm.

[0013] In one embodiment, the sound-absorbing material may have a normal incidence sound absorption coefficient of 0.3 or more at any frequency of 1 kHz or less, as measured in accordance with JIS A 1405-1. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a sound-absorbing material that has excellent sound-absorbing properties in the low frequency range. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a schematic cross-sectional view of a sound-absorbing material. [Figure 2] FIG. 10 is a diagram showing the normal incident sound absorption coefficient of the example. [Figure 3] FIG. 10 is a diagram showing the normal incident sound absorption coefficient of the example. [Figure 4] FIG. 10 is a diagram showing the normal incident sound absorption coefficient of the example. [Figure 5] FIG. 10 is a diagram showing the normal incident sound absorption coefficient of the example. [Figure 6] FIG. 10 is a diagram showing the normal incident sound absorption coefficient of the example. [Figure 7] FIG. 10 is a diagram showing the normal incident sound absorption coefficient of a comparative example. [Figure 8] FIG. 10 is a diagram showing the normal incident sound absorption coefficient of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0016] <Sound-absorbing material> Figure 1 is a schematic cross-sectional view of a sound-absorbing material. Sound-absorbing material 10 comprises, in this order, a resin film 1, a first base material layer 2 having communicating holes, and a second base material layer 3 having communicating holes. Sound (acoustic energy) incident from the resin film side is dissipated as thermal energy as it passes through the sound-absorbing material. This results in the attenuation of sound.

[0017] (base material layer) Examples of the substrate layer having continuous pores include a resin foam, a nonwoven fabric, a porous polymer, and a porous ceramic. Of these, the substrate layer may be a resin foam or a nonwoven fabric from the viewpoint of excellent sound absorption characteristics in the low frequency range. The first substrate layer and the second substrate layer may be made of the same material or different materials.

[0018] Examples of materials for the resin foam include polyethylene resin, polypropylene resin, polyurethane resin, polyester resin, acrylic resin, polystyrene resin, melamine resin, silicone resin, natural rubber, synthetic rubber, etc. From the viewpoints of heat resistance, flame retardancy, etc., the material for the resin foam may be melamine resin.

[0019] Fibers constituting nonwoven fabrics include organic fibers and inorganic fibers. Examples of organic fibers include polyolefin fibers such as polyethylene (low density or high density), polypropylene, copolymerized polyethylene, and copolymerized polypropylene; polyester fibers such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate; acrylic fibers, polyamide fibers, nylon fibers, rayon fibers, and natural fibers such as wool. Examples of inorganic fibers include glass fibers, metal fibers, ceramic fibers, and carbon fibers. The fibers constituting nonwoven fabrics may contain one or more of these fibers.

[0020] From the viewpoint of excellent sound absorption characteristics in the low frequency range, the thickness of the base material layer can be 0.1 to 50 mm, or alternatively, 0.5 to 20 mm, 2.0 to 20 mm, or 2.0 to 10 mm. The first base material layer and the second base material layer may have the same thickness or different thicknesses. From the viewpoint of excellent sound absorption characteristics in the low frequency range, the thickness of the first base material layer (the base material layer on the sound incident side) may be thinner than the thickness of the second base material layer.

[0021] The weight of the base layer is 10 to 1000 g / m from the viewpoint of excellent sound absorption characteristics in the low frequency range. 2 and can be set to 30 to 800 g / m 2 and 30 to 700 g / m 2 and may be 50 to 500 g / m 2 and 150 to 300 g / m 2 The first base material layer and the second base material layer may have the same basis weight or different basis weights.

[0022] The density of the base material layer is 0.005 to 1.0 g / cm from the viewpoint of excellent sound absorption characteristics in the low frequency range. 3 and the density can be 0.010 to 0.50 g / cm 3 and may be 0.010 to 0.20 g / cm 3 and may be 0.020 to 0.20 g / cm 3 and may be 0.020 to 0.15 g / cm 3 The first substrate layer and the second substrate layer may have the same density or different densities.

[0023] From the viewpoint of achieving excellent sound absorption characteristics in the low frequency range, the sound-absorbing material may further include other substrate layers having communicating holes. That is, in addition to the first substrate layer having communicating holes and the second substrate layer having communicating holes, the sound-absorbing material may further include a third substrate layer having communicating holes, a fourth substrate layer having communicating holes, etc. The substrate layers may be made of the same material or different materials.

[0024] (resin film) Examples of resins that may be used to form the resin film include polyolefin resins such as polyethylene (low density or high density), polypropylene, copolymerized polyethylene, and copolymerized polypropylene; polyester resins such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate; fluorine-based resins such as PTFE, FEP, and PFA; polyimide resins, polyamide resins, aramid resins, vinyl chloride resins, acrylic resins, polycarbonate resins, polyphenylene sulfide resins, polyvinyl alcohol resins, polystyrene resins, polyacrylonitrile resins, and ethylene-vinyl acetate resins.

[0025] From the viewpoint of excellent sound absorption characteristics in the low frequency range, the thickness of the resin film can be 0.5 to 500 μm, or alternatively 5 to 250 μm, or 10 to 100 μm. The first resin film and the second resin film may have the same thickness or different thicknesses. Furthermore, from the viewpoint of excellent sound absorption characteristics in the low frequency range, the ratio of the thickness of the resin film to the thickness of the base layer (thickness of base layer / thickness of resin film) can be 1 to 20,000, or alternatively 10 to 10,000, or alternatively 100 to 1,000.

[0026] The resin film may have a metal vapor deposition layer on its surface from the viewpoint of improving the sound absorption effect by adjusting the film properties and imparting a heat ray reflection function. That is, the sound absorbing material may further have a metal vapor deposition layer on the surface of at least one of the first resin film and the second resin film. The metal vapor deposition layer can be formed by physical vapor deposition such as vacuum deposition or chemical vapor deposition of a metal such as aluminum, copper, zinc, a zinc alloy, or silver. The metal vapor deposition layer may be provided on both sides or one side of the resin film.

[0027] The resin film may be a perforated film from the viewpoint of improving the sound absorption effect in the low frequency range and adjusting the sound absorption frequency peak. The perforated film may have holes arranged in a lattice or diamond shape. From the viewpoint of excellent sound absorption characteristics in the low frequency range, the holes may be circular with a diameter of 0.1 to 50.0 mm, 0.2 to 10.0 mm, or 0.3 to 5.0 mm. The shape of the holes may be circular, elliptical, rectangular, polygonal, etc.

[0028] From the viewpoint of achieving excellent sound absorption characteristics in the low frequency range, a resin film may be further provided between a first substrate layer having communicating holes and a second substrate layer having communicating holes. Furthermore, when the sound-absorbing material further includes a third substrate layer, a fourth substrate layer, etc., a resin film may be further provided between these substrate layers. Each resin film may be made of the same material or different materials.

[0029] (adhesive layer) The sound-absorbing material may further include an adhesive layer between each of the above layers. For example, the sound-absorbing material may include an adhesive layer between the resin film and the first substrate layer, or between the first substrate layer and the second substrate layer. Examples of adhesive layers include polyester resins, vinyl acetate resins, ethylene-vinyl acetate copolymer resins, isobutene-maleic anhydride copolymer resins, acrylic copolymer resins, acrylic monomers, acrylic oligomers, vinyl chloride resins, urethane resins (including moisture-curable types), silylated urethane resins, epoxy resins, modified epoxy resins, polyolefin resins such as polyethylene resins, ionomer resins, silicone resins, modified silicone resins, synthetic rubbers such as styrene-butadiene rubber, chloroprene rubber, and nitrile rubber, natural rubbers such as isoprene rubber, water glass, and silicates, or layers consisting of laminates in which layers containing these adhesive components are provided on both sides of a support made of paper, cloth, resin tape, metal tape, or the like. The adhesive layer may also be an adhesive sheet in which the above-mentioned adhesive component-containing layer or the above-mentioned laminate is provided on both sides of a resin film. In this case, the resin film may be any of the resin films described above. The adhesive layers may be made of the same material or different materials.

[0030] The thickness of the adhesive layer is not particularly limited, but may be 0.01 to 500 μm, or may be 1 to 250 μm. The adhesive layers may have the same thickness or different thicknesses.

[0031] The thickness of the sound absorbing material can be 1 to 100 mm, or may be 2 to 50 mm, or may be 5 to 30 mm, from the viewpoints of sound absorption characteristics, workability of the material, space saving, and the like.

[0032] The sound-absorbing material may have a normal incidence sound absorption coefficient of 0.3 or greater, or 0.4 or greater, measured in accordance with JIS A 1405-1 at any frequency of 1 kHz or less, specifically at least one of 250 Hz, 500 Hz, and 1 kHz. The normal incidence sound absorption coefficient may be 0.3 or greater, or may be 0.4 or greater, at 1 kHz. The normal incidence sound absorption coefficient may be 0.2 or greater, or may be 0.3 or greater, at 750 kHz. The sound absorption coefficient may be 0.1 or greater, or may be 0.15 or greater, at 500 kHz.

[0033] <Method of manufacturing sound-absorbing material> The sound-absorbing material can be manufactured by laminating each layer. The sound-absorbing material may be used in a state in which the layers are bonded together by providing an adhesive layer as described above, or may be used without bonding the layers together. Alternatively, an adhesive layer may be provided only between some of the layers. The laminate constituting the sound-absorbing material may be used in a state in which it is housed in a housing.

[0034] <Applications of sound-absorbing materials> The sound-absorbing material has excellent sound-absorbing properties in the low-frequency range. Therefore, the sound-absorbing material can be suitably used in applications such as automobiles, railway vehicles, aircraft, ships, buildings such as houses, electronic devices, precision machinery, etc. The low-frequency range here can be a frequency range of 1 kHz or less, or may be a frequency range of 800 Hz or less, a frequency range of 750 Hz or less, or a frequency range of 500 Hz or less. [Example]

[0035] Below are examples (However, Examples 11 to 16 are reference examples.) The present invention will be described in more detail below with reference to the following examples, but the present invention is not limited to these examples.

[0036] (Preparation of base layer) The substrate layers shown in Table 1 were prepared.

[0037] [Table 1]

[0038] (Preparing the resin film) The following resin films were prepared. Double-sided aluminum-deposited polyethylene terephthalate film (Al-deposited PET): Thickness 12 μm Polyethylene terephthalate film A (PET-A): Thickness 12 μm Polyethylene terephthalate film B (PET-B): Thickness 25 μm Polyethylene terephthalate film C (PET-C): Thickness 50 μm Polyethylene terephthalate film D (PET-D): Thickness 250 μm Biaxially oriented polypropylene film (OPP): thickness 20 μm Polyethylene film (PE): 25 μm thick

[0039] (Preparing the adhesive layer) The following adhesive layers were prepared: Double-sided tape A: 3M Japan Ltd., PGD-100 (0.12 mm thick, base material: nonwoven fabric) Double-sided tape B: Hitachi Chemical Co., Ltd., Hibon 25-563 (0.15 mm thick, base material: Al foil) Adhesive A: 3M Japan Co., Ltd., Spray Glue No. 77 Adhesive B: KLEBCHEMIE MGBecker GmbH & Co.KG, polyolefin hot melt resin (966P, 50g / m 2 Coating) Adhesive C: KLEBCHEMIE MGBecker GmbH & Co.KG, synthetic rubber hot melt resin (939S, 50g / m 2 Coating) Adhesive D: KLEBCHEMIE MGBecker GmbH & Co.KG, moisture-curing polyurethane hot melt resin (PUR700.5, 50g / m 2 Coating) Adhesive sheet A: The above double-sided tape A is provided on both sides of the above Al-deposited PET. Adhesive sheet B: A layer of the adhesive A on both sides of the Al-deposited PET Adhesive sheet C: Kurabo Industries, polyolefin hot melt resin sheet (X4300, 0.05 mm thick) Adhesive sheet D: Kurabo Industries, polyester sheet hot melt resin sheet (G-5, 0.03 mm thick) Adhesive sheet E: Kurabo Industries, polyurethane hot melt resin sheet (S-1700, 0.05 mm thick)

[0040] (Production of sound-absorbing material) Sound-absorbing materials were manufactured with the configurations shown in Tables 2 and 3. Double-sided tape, adhesive, or adhesive sheet was used to adhere each layer. In the tables marked with *1, adhesion between the resin film and the first base material layer was performed with double-sided tape A or adhesive A, and adhesion between the first base material layer and the second base material layer was performed with adhesive sheet A, adhesive sheet B, or double-sided tape B.

[0041] [Table 2]

[0042] [Table 3]

[0043] (Evaluation of sound absorption properties of sound absorbing materials) The normal incidence sound absorption coefficient of each of the produced sound-absorbing materials was measured as follows. Sound was incident from the layer side shown on the left in Table 2. The measurement results are shown in Tables 4 and 5. Device name: 4206 Impedance Tube (Brüel & Kjær) Measurement method: Normal incident sound absorption coefficient (compliant with JIS A 1405-1) Measurement range: 50 to 1600 Hz

[0044] [Table 4]

[0045] [Table 5]

[0046] 2 to 8 are diagrams showing the normal incidence sound absorption coefficients of the examples and comparative examples. As shown in the figures, it is clear that the sound absorbing materials of the examples have excellent sound absorption characteristics in the low frequency range. [Explanation of symbols]

[0047] 1...resin film, 2...first base material layer having communicating holes, 3...second base material layer having communicating holes, 10...sound-absorbing material.

Claims

1. a resin film (excluding those having a plurality of through holes in the thickness direction), a first base material layer having communicating holes, and a second base material layer having communicating holes, in this order; A metal vapor-deposited layer is further provided on at least one surface of the resin film, the first base material layer and the second base material layer are nonwoven fabrics, The sound-absorbing material, wherein the first base material layer and the second base material layer have a basis weight of 50 to 500 g / m 2 .

2. The sound-absorbing material according to claim 1 , wherein the thickness of the first base material layer is smaller than the thickness of the second base material layer.

3. 3. The sound-absorbing material according to claim 1, wherein the resin film is made of polyolefin, polyester, or polyamide.

4. The sound-absorbing material according to any one of claims 1 to 3, wherein the metal vapor-deposited layer contains aluminum, copper, zinc, a zinc alloy, or silver.

5. The sound-absorbing material according to any one of claims 1 to 4, further comprising an adhesive layer between the resin film and the first base material layer, and between the first base material layer and the second base material layer.

6. The sound-absorbing material according to any one of claims 1 to 5, having a thickness of 1 to 100 mm.

7. The sound-absorbing material according to any one of claims 1 to 6, which has a normal incidence sound absorption coefficient of 0.3 or more at any frequency of 1 kHz or less, measured in accordance with JIS A 1405-1.

8. The sound-absorbing material according to claim 1, wherein the first base material layer and the second base material layer have a density of 0.010 to 0.50 g / cm 3 .

9. An acoustic material described in any one of claims 1 to 8, wherein the thickness of the first substrate layer / thickness of the resin film and the thickness of the second substrate layer / thickness of the resin film are 10 to 10,000.

10. An acoustic material described in any one of claims 1 to 9, wherein the fibers constituting the nonwoven fabric are organic fibers.

11. An acoustic material described in any one of claims 1 to 10, wherein the thickness of the first substrate layer and the second substrate layer is 2.0 to 20 mm.

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