JP2016157113A - Sound absorption material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound absorption material having excellent sound absorbency in a low frequency domain while achieving a thinner material, the sound absorption material also having a sound insulation property.SOLUTION: A sound absorption material 1 includes: a sound absorption layer 3; a sound insulation layer 2 arranged below the sound absorption layer 3; and a space layer 4 configured to divide the sound absorption layer 3 and the sound insulation layer 2 in a vertical direction. Accordingly, the sound absorption material 1 is capable of setting thickness T1 to be thin while having excellent sound absorbency in a low frequency domain.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sound absorbing material.

  Conventionally, it is known to provide a sound absorbing material in various structures such as vehicles and buildings in order to prevent noise.

  For example, a sound absorbing material made of polyurethane foam has been proposed (see, for example, Patent Document 1).

JP 2008-32977 A

  However, in the sound absorbing material described in Patent Document 1, the sound absorbing material is formed thick in order to obtain excellent sound absorbing properties not only in the high frequency region but also in the low frequency region. However, such a sound absorbing material has a problem that various structures are enlarged.

  On the other hand, when the sound absorbing material described in Patent Document 1 is thinly formed, there is a problem that the sound absorbing property in the low frequency region is lowered.

  Further, the conventional lightweight fibrous sound absorbing material and the thinly formed sound absorbing material have a defect that there is almost no sound insulation.

  An object of the present invention is to provide a sound-absorbing material that is excellent in sound-absorbing properties in a low-frequency region while being able to reduce the thickness. Another object of the present invention is to provide a sound absorbing material that also has sound insulation.

  The present invention (1) is a sound absorbing material comprising a sound absorbing layer, a sound insulating layer disposed on one side in the thickness direction of the sound absorbing layer, and a space layer that separates the sound absorbing layer and the sound insulating layer in the thickness direction. Including.

  Since the sound absorbing material includes a spatial layer that separates the sound absorbing layer and the sound insulating layer in the thickness direction, the sound in the low frequency region can be dispersed in the direction orthogonal to the thickness direction in the spatial layer to attenuate the sound. .

  Therefore, this sound absorbing material is excellent in sound absorbing properties in a low frequency region.

  In addition, since the sound absorbing material may be configured from the sound absorbing layer, the sound insulating layer, and the spatial layer so that the sound in the low frequency region can be dispersed in the orthogonal direction in the spatial layer, the thickness of the sound absorbing material can be reduced. .

  Furthermore, this sound absorbing material has excellent sound insulation.

  The present invention (2) further includes a plurality of pillar members extending in the thickness direction and spaced apart from each other in a direction orthogonal to the thickness direction, and the plurality of pillar members include the sound absorbing layer and the sound insulating layer. The sound-absorbing material described in (1) is included.

  In this sound absorbing material, a plurality of pillar members extending in the thickness direction and spaced apart from each other in the direction orthogonal to the thickness direction are arranged between the sound absorbing layer and the sound insulating layer, so that a space layer is reliably formed. can do. Moreover, the sound dispersed in the orthogonal direction can be scattered by the plurality of column members.

  The present invention (3) further includes a second sound insulation layer interposed between the column member and the sound absorption layer, and the second sound insulation layer has an area density of 0.01 or more, (2) Including the sound-absorbing material described.

  Since this sound absorbing material further includes a second sound insulating layer having a surface density equal to or higher than the lower limit, it is possible to ensure excellent sound absorbing properties and sound insulating properties while achieving weight reduction.

  Moreover, the column member can be supported by the second sound insulating layer. A sound absorbing material in a bent form can be provided by causing the sound absorbing material to follow the structure.

  The present invention (4) includes the sound absorbing material according to (2) or (3), wherein each of the plurality of column members has an inclined surface inclined with respect to the thickness direction.

  According to this sound absorbing material, in the spatial layer, sound incident along the thickness direction can be scattered in a direction intersecting both the thickness direction and the orthogonal direction by the inclined surface inclined with respect to the thickness direction. Therefore, the sound absorbing property of the sound absorbing material can be improved.

  The present invention (5) includes the sound absorbing material according to (4), wherein each of the plurality of column members has a substantially conical shape in which a cross-sectional area increases toward one side in the thickness direction.

  According to this sound absorbing material, in the spatial layer, sound incident from one side in the thickness direction to the other side is favorably scattered in a direction intersecting both the thickness direction and the orthogonal direction by the conical surfaces of the plurality of column members. Can do. Therefore, the sound absorbing property of the sound absorbing material can be improved.

  This invention (6) contains the sound-absorbing material as described in any one of (1)-(5) further provided with the obstruction | occlusion part which obstruct | occludes the peripheral edge part of the said space layer.

  According to this sound absorbing material, the sound that is dispersed in the direction perpendicular to the thickness direction can be confined by the blocking portion. Therefore, the sound absorbing property of the sound absorbing material can be improved.

  The present invention (7) includes the sound absorbing material according to (6), wherein the blocking portion is a peripheral end portion of the sound absorbing layer.

  In order to close the peripheral end portion of the space layer, when a closing member is separately provided, the configuration becomes complicated.

  However, in this sound absorbing material, since the peripheral end portion of the sound absorbing layer is used as a blocking portion, the structure of the sound absorbing material can be simplified.

  The sound-absorbing material of the present invention can be reduced in thickness while being excellent in sound-absorbing properties in a low frequency region. The sound absorbing material of the present invention has excellent sound insulation properties.

FIG. 1 shows a partially cutaway perspective view of a first embodiment of a sound absorbing material of the present invention. FIG. 2 is a plan view of the sound absorbing material shown in FIG. 1 (a view in which a sound absorbing layer described later is omitted). FIG. 3 is a cross-sectional view taken along line AA of the sound absorbing material shown in FIGS. 1 and 2. 4 shows an exploded view of the sound absorbing material shown in FIG. FIG. 5 shows a cross-sectional view of a modification of the first embodiment (a mode in which the column member has a conical shape). FIG. 6 shows a cross-sectional view of a modification of the first embodiment (an aspect in which the column member has a cylindrical shape). FIG. 7 shows a cross-sectional view of a modification of the first embodiment (a mode in which a blocking member is separately provided). FIG. 8 shows a cross-sectional view of the sound absorbing material according to the second embodiment of the present invention. FIG. 9 shows an exploded view of the sound absorbing material shown in FIG. FIG. 10 shows a part of a cross-sectional view in the third embodiment of the sound-absorbing material of the present invention. FIG. 11 shows a part of a sectional view of a modification of the third embodiment. FIG. 12 is a graph showing the relationship between the normal incident sound absorption coefficient and the frequency in the example. FIG. 13 is a graph showing the relationship between transmitted sound insertion loss and frequency in the example.

<First Embodiment>
In each drawing, directions such as a vertical direction, a horizontal direction, and a front-rear direction follow the directional arrows described in each drawing.

  In FIG. 3, the up and down direction on the paper surface is the up and down direction (thickness direction, first direction) of the sound absorbing material (described later), and the upper side of the paper surface is the upper side (one side in the thickness direction, one side in the first direction). The side is the lower side (one side in the thickness direction, one side in the first direction). Further, the left-right direction of the drawing is a direction (second direction) orthogonal to the up-down direction, the left side of the drawing is the left side (one side in the second direction), and the right side of the drawing is the right side (the other side in the second direction). The paper thickness direction is the front-rear direction (the direction perpendicular to the vertical direction and the left-right direction, the third direction), the front side of the paper is the front side (one side in the third direction), the back side of the paper is the rear side (the other in the third direction Side).

  In FIG. 2, a sound absorbing layer (described later) is omitted in order to clearly show the shape of the column member. 3 to 9, for the sake of convenience, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed from those of the actual one in order to clearly illustrate the cross-sectional shape of the space layer forming member (described later).

  As shown in FIGS. 1 and 3, the sound absorbing material 1 includes a sound insulating layer 2, a sound absorbing layer (first sound absorbing layer) 3 disposed on the upper side of the sound insulating layer 2 (an example on the other side in the thickness direction), and a sound insulating layer. 2 and a space layer forming member 7 disposed between the sound absorbing layer 3 and the sound absorbing layer 3.

  The sound insulating layer 2 is the lowest layer in the sound absorbing material 1. As shown in FIGS. 1 and 2, the sound insulation layer 2 is formed in a flat plate shape (or layer shape) having an outer shape corresponding to the outer shape of the sound absorbing material 1 in plan view. The sound insulation layer 2 is not particularly limited as long as sound insulation can be performed.

  The sound insulation is performed by the sound insulation layer 2 when the sound absorbing material 1 is arranged in the propagation direction in which the sound is propagated from the sound source 31 indicated by the phantom line in FIG. 3, thereby transmitting the sound insulation layer 2. This is an action (role) for effectively preventing (passing) or detouring and propagating downstream in the propagation direction (lower side in FIG. 3). The sound insulation layer 2 and the sound insulation properties are the members and properties that can be sound-insulated.

  Examples of the sound insulating layer 2 include a pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) formed from a pressure-sensitive adhesive composition into a layer (sheet).

  Examples of the pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) include pressure-sensitive adhesives (pressure-sensitive adhesive) such as acrylic and butyl.

  Further, the pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) contains a rubber component, and examples thereof include those that are pressure-bonded while heating. Such a pressure-sensitive adhesive layer (pressure-sensitive adhesive layer) is made of a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition contains, for example, a rubber component as a main component and a tackifying resin, a curing component, a filler, an additive, and the like as subcomponents (optional components).

  Examples of rubber components include ethylene-vinyl acetate copolymer (EVA), ethylene / propylene / diene rubber (EPDM), styrene / butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), and styrene-vinyl. Examples include isoprene copolymers and natural rubber. The rubber component can be used alone or in combination. The rubber component is preferably EVA or a styrene-vinylisoprene copolymer. These can be used alone or in combination.

  Examples of the tackifying resin include rosin resin, terpene resin, aliphatic resin, aromatic resin, alicyclic resin, coumarone-indene resin, and the like. Tackifying resins can be used alone or in combination. As the tackifier resin, an aliphatic resin is preferably used.

  Examples of the curing component include an epoxy resin, a silicone resin, a thermosetting polyimide resin, a phenol resin, a urea resin, and a melamine resin. The curing component can be used alone or in combination. The curing component is preferably an epoxy resin.

  Examples of the filler include calcium carbonate and silica. The filler can be used alone or in combination.

  Examples of the additive include pigments such as carbon black and softeners such as liquid polybutene. Additives can be used alone or in combination.

  The compounding ratio of the rubber component in the pressure-sensitive adhesive composition is, for example, 20% by mass or more, for example, 60% by mass or less, and the compounding ratio of the tackifying resin in the pressure-sensitive adhesive composition is, for example, 5% by mass. As described above, for example, it is 10% by mass or less, and the blending ratio of the curing component in the pressure-sensitive adhesive composition is, for example, 1% by mass or more, for example, 5% by mass or less, and the filler in the pressure-sensitive adhesive composition. The blending ratio of, for example, exceeds 10% by weight and is, for example, 70% by weight or less, and the blending ratio of the additive in the pressure-sensitive adhesive composition is, for example, 1% by weight or more, for example, 5% by weight. % Or less.

  In order to obtain the sound insulation layer 2, for example, a kneaded material is first prepared by blending and kneading the above-mentioned pressure sensitive adhesive (pressure sensitive adhesive composition). Next, the kneaded product is formed into a sheet.

  The thickness of the sound insulation layer 2 is, for example, 10 mm or less, more preferably 5 mm or less, preferably 2 mm or less, and for example, 0.01 mm or more, preferably 0.1 mm or more.

  As shown in FIGS. 1 and 3, the sound absorbing layer 3 is the uppermost layer in the sound absorbing material 1. As shown in FIGS. 1 and 2, the sound absorbing layer 3 is formed in a flat plate shape (or layer shape) having an outer shape corresponding to the outer shape of the sound insulating layer 2 in a plan view. The sound absorbing layer 3 is not particularly limited as long as sound insulation can be performed.

  As shown in FIG. 3, when the sound absorbing material 1 is disposed in the propagation direction in which sound is propagated from the sound source 31, the sound absorption is absorbed by the sound absorbing layer 3. This is an action (role) for effectively preventing reflection (returning) to the upstream side in the propagation direction (upper side in FIG. 3). The sound-absorbing layer 3 and the sound-absorbing property are the members and properties that can absorb the sound.

  Examples of the sound absorbing layer 3 include a foam layer and a fiber layer. These can be used alone as a single layer or can be used in combination as a multilayer. In FIG. 3, a mode in which the sound absorbing layer 3 is used as a single layer is illustrated.

  The peripheral end portions (left and right end portions and front and rear end portions) of the sound absorbing layer 3 are in contact with the upper surface of the peripheral end portion of the sound insulating layer 2 (more specifically, pressure sensitive bonding). On the other hand, the central portion other than the peripheral end portion of the sound absorbing layer 3 bulges upward from the peripheral end portion of the sound absorbing layer 3, thereby forming a spatial layer 4 described below. That is, the sound absorbing layer 3 is formed in a shape that bulges upward as it goes from the peripheral end portion toward the center portion (substantially U-shaped or U-shaped cross section that opens downward). Yes.

  Examples of the foam layer include polyurethane foam, EPDM foam, polystyrene foam, polyolefin foam, chloroprene foam, and polyester foam. Preferably, EPDM foam and polyurethane foam are used.

  The foam layer is, for example, an open cell structure (open cell structure) in which a plurality of bubbles communicate with each other, for example, a closed cell structure (single cell structure) that independently contains a plurality of cells, for example, a semi-continuous semi-closed cell structure. Have The foamed layer preferably has an open cell structure and a semi-continuous semi-closed cell structure from the viewpoint of sound absorption.

  A commercially available product can be used as the foam layer, and specifically, EPT SEALER (EPDM foam, manufactured by Nitto Denko Corporation) or the like is used.

  As for a fiber layer, a nonwoven fabric, a woven fabric, etc. are mentioned, for example, Preferably a nonwoven fabric is mentioned.

  Examples of the non-woven fabric include polyester non-woven fabric such as PET non-woven fabric, polyolefin non-woven fabric such as polypropylene non-woven fabric, nylon non-woven fabric such as non-woven fabric made of polyester and rayon, and the like. As a nonwoven fabric, Preferably, a polyester nonwoven fabric is mentioned.

  A nonwoven fabric is manufactured by the needle punch method, the chemical bond method, the spun bond method, etc., for example. The nonwoven fabric is preferably produced by a needle punch method, a chemical bond method, more preferably, a needle punch method.

  The fiber layer may be impregnated with a thermosetting resin. As a fiber layer, Preferably, the nonwoven fabric impregnated with the thermosetting resin is mentioned.

  Examples of the thermosetting resin include resorcinol resin and phenol resin, and preferably resorcinol resin.

  Commercially available products can be used as the fiber layer. Specifically, as the nonwoven fabric impregnated with the thermosetting resin, a DFK processed nonwoven fabric (trade name, manufactured by Nagoya Yuka Co., Ltd.) or the like is used.

  The thickness of the sound absorbing layer 3 is, for example, 1 mm or more, preferably 2 mm or more, and for example, 50 mm or less, preferably 30 mm or less.

  As shown in FIGS. 1 and 2, the space layer forming member 7 extends in the left-right direction and the front-rear direction, and is smaller than the sound insulating layer 2 and the sound absorbing layer 3 in plan view. That is, as shown in FIG. 2 and FIG. 3, the space layer forming member 7 is provided on the inner side from the peripheral end portion of the sound insulating layer 2, and the upper surface of the peripheral end portion of the sound insulating layer 2 is the periphery of the sound absorbing layer 3. It is in contact with the lower surface of the end (pressure-sensitive adhesion). The space layer forming member 7 is integrally provided with a column member 8 and a lower connecting wall 9.

  A plurality of column members 8 are provided in the left-right direction and the front-rear direction (an example of a direction orthogonal to the thickness direction). The plurality of column members 8 are arranged in parallel in the left-right direction. Specifically, as shown in FIG. 2, the column members 8 include a column array 16 arranged in a plurality of rows at intervals in the left-right direction. ing. In addition, a plurality of column rows 16 are arranged in the front-rear direction. The plurality of column rows 16 are arranged in a bowl shape in the front-rear direction. That is, in detail, each column member 8 in one column row 16 (16A) has each column in the other column row 16 (16B) on the rear side of one column row 16 (16A) when projected in the front-rear direction. The column member 8 is disposed so as to be displaced.

  As shown in FIGS. 1 and 3, each of the plurality of column members 8 is formed in a substantially conical shape whose cross-sectional area increases toward the lower side, specifically, a truncated cone shape. Each of the plurality of column members 8 is integrally provided with an inclined peripheral wall 12 and an upper connecting wall 13 that connects (closes) the upper end portion of the inclined peripheral wall 12.

  The inclined peripheral wall 12 is inclined with respect to the vertical direction (specifically, the vertical direction, the horizontal direction, and the front-rear direction). Specifically, the inclined circumferential wall 12 has an opening cross-sectional area along the left-right direction and the front-rear direction that increases toward the lower side, a cut surface along the up-down direction and the left-right direction, and a cut surface along the up-down direction and the front-rear direction. Are formed in a substantially tapered shape. The outer peripheral surface of the inclined peripheral wall 12 is formed as an inclined surface 14 that is inclined with respect to the thickness direction.

  The upper connecting wall 13 is formed in a substantially disc shape. The upper surface of the upper connecting wall 13 is in contact (adhesion) with the lower surface of the sound absorbing layer 3.

  The lower connecting wall 9 connects the lower ends of the plurality of column members 8 to each other, and is formed in a substantially flat plate shape parallel to the upper connecting wall 13. The lower surface of the lower connecting wall 9 is in contact (pressure-sensitive adhesion) with the upper surface of the central portion of the sound insulating layer 2.

  Examples of the material for forming the space layer forming member 7 include a resin, and specifically, a thermoplastic resin. Examples of the thermoplastic resin include olefin-based resins (for example, polyethylene, polypropylene, or copolymers thereof), polycarbonate, polyester, polystyrene, acrylic resin, and the like. Preferably, an olefin resin, more preferably, polypropylene is used.

  The dimension of the space layer forming member 7 is appropriately set, and the vertical length of each of the plurality of column members 8 is, for example, 1 mm or more, preferably 3 mm or more, and for example, 100 mm or less, preferably It is 50 mm or less. The angle formed between each inclined peripheral wall 12 of the plurality of column members 8, the lower connecting wall 9 and the upper connecting wall 13 is, for example, 20 degrees or more, preferably 30 degrees or more, and, for example, 150 degrees or less. , Preferably, it is 120 degrees or less. The diameter (maximum length) of the upper connecting wall 13 is, for example, 0.5 mm or more, preferably 1 mm or more, and for example, 10 mm or less, preferably 5 mm or less. The diameter (maximum length) of the lower end portion of the inclined peripheral wall 12 is, for example, 0.1 mm or more, preferably 3 mm or more, and for example, 50 mm or less, preferably 10 mm or less. The pitch in the left-right direction of the plurality of column members 8 (the sum of the length in the left-right direction of the column members 8 and the length between the column members 8 arranged adjacent in the left-right direction) is, for example, 1 mm or more, preferably 3 mm or more. Yes, for example, 50 mm or less, preferably 20 mm or less. The pitch in the front-rear direction of the plurality of columnar rows 16 is, for example, 1 mm or more, preferably 3 mm or more, and for example, 50 mm or less, preferably 20 mm or less.

  The thickness of the column member 8, that is, the thickness of the inclined peripheral wall 12 and the thickness of the upper connecting wall 13 is, for example, 50 μm or more, preferably 100 μm or more, and for example, 5000 μm or less, preferably 3000 μm or less. The thickness of the lower connecting wall 9 is substantially the same as the thickness of the column member 8.

  The space layer forming member 7 is formed by, for example, extruding the above-described resin (specifically, a thermoplastic resin) into a sheet, and then forming the sheet with an embossing roller having a protrusion corresponding to the column member 8. Obtained by thermoforming into shape.

  Moreover, a commercial item can be used as the space layer forming member 7, and specifically, a core cone series (also known as single cone, manufactured by Ube Eximo Co., Ltd.) is used.

  Since the above-described space layer forming member 7 is disposed between the sound insulating layer 2 and the sound absorbing layer 3, the space layer 4 is formed between the sound insulating layer 2 and the sound absorbing layer 3.

  The space layer 4 has two spaces 15 and 18, that is, an upper space 15 and a lower space 18. Preferably, the space layer 4 is formed of an upper space 15 and a lower space 18.

  The upper space 15 is a space that extends in the left-right direction and the front-rear direction of the sound absorbing material 1 on the upper side of the inclined peripheral wall 12 and the lower connecting wall 9 of the plurality of column members 8. Specifically, the upper space 15 includes a lower surface of the central portion of the sound absorbing layer 3 (excluding a portion in contact with the upper connecting wall 13), an outer peripheral surface of the inclined peripheral wall 12 (inclined surface 14), and the lower connecting wall 9. It is partitioned by the upper surface. In addition, the peripheral ends (both ends in the left-right direction and both ends in the front-rear direction) of the upper space 15 are closed by the peripheral ends (both ends in the left-right direction and both ends in the front-rear direction) of the sound absorbing layer 3. Therefore, the peripheral end portion of the sound absorbing layer 3 constitutes a closing portion 19.

  The lower space 18 is a plurality of closed spaces formed corresponding to each of the plurality of column members 8 on the lower sides of the inclined peripheral walls 12 and the upper connection walls 13 of the plurality of column members 8. Specifically, each of the plurality of lower spaces 18 includes an inner peripheral surface of the inclined peripheral wall 12, a lower surface of the upper connecting wall 13, and an upper surface of the central portion of the sound insulating layer 2 (excluding a portion that contacts the lower connecting wall 9. ).

  The thickness T at the center of the sound absorbing material 1 (that is, the total thickness T at the center of the sound insulating layer 2, the sound absorbing layer 3, and the space layer forming member 7) is, for example, 100 mm or less, more preferably 50 mm or less, 30 mm or less, and for example, 5 mm or more. If thickness T is below the said upper limit, the sound-absorbing material 1 can be made thin. The thickness at the peripheral edge of the sound absorbing material 1 is the total thickness of the sound insulating layer 2 and the sound absorbing layer 3 and is, for example, 1 mm or more, preferably 2 mm or more, and, for example, 50 mm or less, preferably 30 mm or less. It is.

  Next, a method for manufacturing the sound absorbing material 1 will be described with reference to FIG.

  First, in this method, as shown in FIG. 4, a sound insulating layer 2, a sound absorbing layer 3, and a space layer forming member 7 are prepared.

  The sound insulating layer 2 and the sound absorbing layer 3 are prepared with the same dimensions in plan view. When the sound insulating layer 2 is a pressure-sensitive adhesive layer (adhesive layer), a release layer (not shown) is laminated in advance on the lower surface of the sound insulating layer 2.

  On the other hand, the space layer forming member 7 is prepared with a size smaller than that of the sound insulating layer 2 and the sound absorbing layer 3 in plan view.

  Next, the space layer forming member 7 is disposed on the upper surface of the central portion of the sound insulating layer 2. As a result, the upper surface of the peripheral end portion of the sound insulating layer 2 is exposed from the space layer forming member 7.

  At this time, when the sound insulating layer 2 is formed of a pressure-sensitive adhesive layer (adhesive layer), the lower surface of the lower connecting wall 9 is pressure-sensitive bonded (adhered) to the upper surface of the central portion of the sound insulating layer 2. Preferably, the lower surface of the lower connecting wall 9 and the upper surface of the central portion of the sound insulating layer 2 are pressure-sensitive bonded (adhered) while heating.

  Next, the sound absorbing layer 3 is disposed on the space layer forming member 7 so that the peripheral end thereof is in contact with the peripheral end of the sound insulating layer 2. Specifically, when the sound insulating layer 2 is formed of a pressure sensitive adhesive layer (adhesive layer), the lower surface of the peripheral end portion of the sound absorbing layer 3 is pressure-sensitive to the upper surface of the peripheral end portion of the sound insulating layer 2. Adhere (stick). As a result, as shown in FIG. 3, the space layer 4 is formed between the sound insulating layer 2 and the sound absorbing layer 3, and the peripheral end portion of the space layer 4 is blocked by the blocking portion 19 of the sound absorbing layer 3.

  Thus, the sound absorbing material 1 is manufactured.

  When the sound absorbing material 1 is used, a peeling layer (not shown) laminated on the lower surface of the sound insulating layer 2 is peeled off from the sound insulating layer 2 as necessary.

  Such a sound absorbing material 1 is applied to various structures such as vehicles and buildings. Specifically, in various structures, it is installed at a location where noise including sound in a low frequency region passes. Specifically, the sound absorbing material 1 is installed in various structures such that the sound absorbing layer 3 faces the sound source 31 side, that is, the upstream side in the noise propagation direction, and the sound insulating layer 2 faces the downstream side in the noise propagation direction. The

  The sound in the low frequency region is, for example, vehicle road noise, specifically 1000 Hz or less, and may include noise of 800 Hz or more.

  Furthermore, the noise may include a sound in a high frequency region, and the sound including such a high frequency region is specifically an engine sound or the like. The sound in the high frequency range is, for example, 2000 Hz or more, further 2500 Hz or more, further 3000 Hz or more, and, for example, noise of 4000 Hz or less.

<Operational effects of the first embodiment>
And since this sound-absorbing material 1 is provided with the space layer 4 which separates the center part of the sound-absorbing layer 3 and the center part of the sound-insulating layer 2 in the thickness direction (vertical direction), in the space layer 4, the sound in the low frequency region is Sound can be attenuated by dispersing in the left-right direction and the front-rear direction.

  Therefore, the sound absorbing material 1 is excellent in sound absorbing properties in a low frequency region.

  Furthermore, the sound absorbing material 1 is excellent in sound insulation.

  Further, since the sound absorbing material 1 may be composed of the sound absorbing layer 3, the sound insulating layer 2, and the space layer 4 so that the sound can be dispersed in the left-right direction and the front-back direction in the space layer 4, the central portion of the sound absorbing material 1 The thickness T can be reduced.

  Further, in the sound absorbing material 1, the plurality of pillar members 8 that extend in the vertical direction and are spaced apart from each other in the left-right direction and the front-rear direction are disposed between the sound insulating layer 2 and the sound absorbing layer 3. The space layer 4 can be reliably formed. Further, the plurality of pillar members 8 can scatter sound dispersed in the left-right direction and the front-rear direction. Therefore, the sound absorbing property of the sound absorbing material 1 can be improved.

  Further, according to the sound absorbing material 1, in the spatial layer 4, the sound incident downward from the sound source 31 indicated by the phantom line is caused by the inclined surface 14 inclined with respect to the vertical direction and the vertical direction and the plane direction (the horizontal direction and It is possible to scatter in a direction intersecting with both directions (ie, the front-rear direction), that is, the left-right direction, the front-rear direction, and the up-down direction. Therefore, the sound absorbing property of the sound absorbing material 1 can be improved.

  Further, according to the sound absorbing material 1, in the spatial layer 4, the sound incident downward from the sound source 31 is intersected by the inclined surfaces 14 of the plurality of column members 8 in both the vertical direction and the surface direction, that is, It is possible to scatter well in the left-right direction, the front-rear direction, and the up-down direction. Therefore, the sound absorbing property of the sound absorbing material 1 can be improved.

  Further, according to the sound absorbing material 1, the sound that disperses the upper space 15 in the left-right direction and the front-rear direction can be effectively confined by the closing portion 19. Therefore, the sound absorbing property of the sound absorbing material 1 can be improved.

<Modification of First Embodiment>
In the first embodiment described above, as shown in FIGS. 1 and 2, the sound absorbing material 1 is formed in a substantially rectangular shape in plan view, but the shape in plan view is not particularly limited. The shape of the sound absorbing material 1 only needs to be formed in an appropriate plan view shape corresponding to the shape of various structures to be installed. For example, the plan view substantially circular shape, the plan view substantially elliptical shape, the plan view substantially triangular shape It can be formed in an appropriate plan view shape such as a shape or a substantially pentagonal shape in plan view.

  In the first embodiment described above, the lower surface of the sound insulation layer 2 is exposed as shown by the solid line in FIG. 3. For example, as shown by the virtual line in FIG. It can also be coated with layer 5.

  As indicated by a virtual line in FIG. 3, the second sound absorbing layer 5 is disposed on the lower surface of the sound insulating layer 2. The second sound absorbing layer 5 is formed in a flat plate shape (or layer shape) having an outer shape corresponding to the outer shape of the sound insulating layer 2. The second sound absorbing layer 5 is a layer for insulating sound leaking from the sound insulating layer 2.

  Examples of the second sound absorption layer 5 include the same layers as the foam layer and the fiber layer mentioned in the sound absorption layer 3, and a foam layer is preferable.

  The thickness of the second sound absorbing layer 5 is, for example, 1 mm or more, preferably 2 mm or more. For example, it is 50 mm or less, preferably 30 mm or less.

  In order to manufacture the sound absorbing material 1 including the second sound absorbing layer 5, first, the second sound absorbing layer 5 is prepared as shown in the phantom line of FIG. 4, and then the sound insulating layer 2 is replaced with the second sound absorbing layer 5. Then, the space layer forming member 7 and the sound absorbing layer 3 are laminated in the same manner as in the first embodiment described above.

  The second sound absorbing layer 5 can improve the sound insulation in the sound absorbing material 1.

  Further, in the first embodiment described above, as shown in FIG. 3, each of the plurality of column members 8 is formed in a truncated cone shape, but the shape of the column members 8 may be substantially conical, Specifically, as shown in FIG. 5, it can also be formed in a conical shape.

  That is, as shown in FIG. 5, the column member 8 does not include the upper connecting wall 13 (see FIG. 3) but includes the apex 33.

  Also according to this modification, the same effects as those of the first embodiment described above can be achieved.

  Further, in the first embodiment described above, as shown in FIG. 3, each of the plurality of column members 8 is formed in a substantially truncated cone shape having the inclined surface 14, but for example, as shown in FIG. Also, it can be formed in a substantially cylindrical shape without the inclined surface 14.

  As shown in FIG. 6, each of the plurality of column members 8 is formed so as to extend along the vertical direction. That is, the peripheral surface 44 of the column member 8 extends in the vertical direction. The thickness of the column member 8 (maximum thickness in the direction perpendicular to the vertical direction) is, for example, 50 μm or more, preferably 100 μm or more, and for example, 5000 μm or less, preferably 3000 μm or less.

  In the description of FIG. 5 described above, each of the plurality of column members 8 is formed in a substantially cylindrical shape, but each of the plurality of column members 8 only needs to extend in the vertical direction. Each of the plurality of column members 8 can also be formed in a substantially polygonal shape such as a substantially triangular prism shape, a substantially quadrangular prism shape, or a substantially hexagonal column shape.

  Furthermore, as shown by the phantom line in FIG. 6, a warp (burl) portion 17 can be formed at the upper end portion of the column member 8. The warped portion 17 is formed in a shape that warps (changes) from the upper end of the column member 8 to one of the lower diagonal left and right directions or one of the lower diagonal front and rear directions. The warped portion 17 is formed integrally with the column member 8, and therefore, the material and thickness of the warped portion 17 are the same as those of the column member 8.

  Further, the number of column members 8 is not particularly limited. Furthermore, the space layer forming member 7 can be configured without providing the lower connecting wall 9. That is, for example, although not shown, the space layer forming member 7 does not include the lower connecting wall 9 but can include only the four column members 8 standing at the four corners of the sound insulating layer 2.

  Furthermore, in the first embodiment described above, as shown in FIGS. 2 and 3, the space layer forming member 7 is formed to be smaller than the sound insulating layer 2 and the sound absorbing layer 3, and the peripheral end portion of the sound absorbing layer 3 is formed. The bottom surface of the sound absorbing layer 2 is pressure-sensitively bonded to the upper surface of the peripheral end portion of the sound insulating layer 2, whereby the peripheral end portion of the sound absorbing layer 3 is used as the closed portion 19. However, as shown in FIG. 7, the sound absorbing material 1 can be configured without forming the blocking portion 19 by forming the space layer forming member 7 with the same dimensions as the sound insulating layer 2 and the sound absorbing layer 3.

  In that case, as shown in FIG. 7, a blocking member 45 made of a foamed layer, a fiber layer, or the like is separately disposed so as to cover the sound insulation layer 2, the space layer forming member 7, and the sound absorbing layer 3. can do.

  The closing member 45 is formed in, for example, a substantially U-shaped (U) shape in a cross-sectional view.

  Preferably, separately, the closing member 45 (see FIG. 7) is not provided, and the peripheral end portion of the sound absorbing layer 3 is the closing portion 19 as shown in FIG. According to such a configuration, since the peripheral end portion of the sound absorbing layer 3 is used as the closing portion 19, the configuration of the sound absorbing material 1 can be simplified.

Second Embodiment
In the second embodiment, the same members and steps as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the first embodiment, the sound absorbing layer 3 is formed as a single layer as shown in FIG. 3, but in the second embodiment, it is formed as a multilayer as shown in FIG.

  As shown in FIG. 8, the sound absorbing layer 3 has a laminated structure, and specifically includes a lower sound absorbing layer 22 and an upper sound absorbing layer 23.

  The lower sound absorbing layer 22 has a layer shape, and is formed in a shape larger than the space layer forming member 7 and smaller than the sound insulating layer 2 in plan view. That is, the lower surface of the central portion of the lower sound absorbing layer 22 is in contact with the upper surface of the upper connection wall 13 of the space layer forming member 7, and the lower surface of the peripheral end portion of the lower sound absorbing layer 22 is the peripheral end portion of the sound insulating layer 2. Is in contact (pressure-sensitive adhesion).

  Further, the peripheral end portion of the upper space 15 is closed by the peripheral end portion of the lower sound absorbing layer 22. Therefore, the peripheral end portion of the sound absorbing layer 3 constitutes the first closing portion 26.

  Examples of the lower sound absorbing layer 22 include the foamed layer described above. The thickness of the lower sound absorbing layer 22 is, for example, 3 mm or more, preferably 5 mm or more, and for example, 50 mm or less, preferably 30 mm or less.

  The upper sound absorbing layer 23 is the uppermost layer in the sound absorbing material 1. The upper sound absorbing layer 23 has a layer shape along the surface (upper surface and side surface) of the lower sound absorbing layer 22, and is formed larger than the lower sound absorbing layer 22. Specifically, the lower surface of the central portion of the upper sound absorbing layer 23 covers the upper surface and side surfaces of the lower sound absorbing layer 22, and the lower surface of the peripheral end portion of the upper sound absorbing layer 23 is exposed from the upper sound absorbing layer 23. Is in contact (pressure-sensitive adhesion).

  Further, the upper sound absorbing layer 23 that covers the first closed portion 26 of the upper sound absorbing layer 23 constitutes a second closed portion 27.

  Examples of the upper sound absorbing layer 23 include the fiber layer described above. The thickness of the upper sound absorbing layer 23 is, for example, 0.1 mm or more, preferably 0.3 mm or more, and for example, 5 mm or less, preferably 3 mm or less.

  The total thickness T of the sound insulating layer 2, the sound absorbing layer 3 and the space layer forming member 7 in the sound absorbing material 1 is, for example, 100 mm or less, more preferably 50 mm or less, preferably 30 mm or less in the central portion. For example, it is 5 mm or more, and it is 60 mm or less, More preferably, it is 50 mm or less, Preferably, it is 30 mm or less in a peripheral edge part, for example, it is 1 mm or more.

  Next, a method for manufacturing the sound absorbing material 1 will be described with reference to FIG.

  First, in this method, as shown in FIG. 9, a sound insulation layer 2, a lower sound absorption layer 22, an upper sound absorption layer 23, a space layer forming member 7 and a second sound absorption layer 5 are prepared.

  An adhesive 24 can be disposed in advance on the lower surface of the upper sound absorbing layer 23. The adhesive 24 is formed into a particle shape from, for example, an olefin-based hot melt adhesive.

  Next, the sound insulation layer 2 is disposed on the upper surface of the second sound absorption layer 5, and then the space layer forming member 7 is disposed on the upper surface of the central portion. At this time, when the sound insulating layer 2 is formed of a pressure-sensitive adhesive layer (adhesive layer), the lower surface of the lower connecting wall 9 is pressure-sensitive bonded (adhered) to the upper surface of the central portion of the sound insulating layer 2. As a result, the peripheral end portion of the sound insulating layer 2 is exposed from the space layer forming member 7.

  Next, the lower sound absorbing layer 22 is disposed on the space layer forming member 7 such that the peripheral end thereof is in contact with the peripheral end of the sound insulating layer 2. Specifically, when the sound insulating layer 2 is formed of a pressure-sensitive adhesive layer (adhesive layer), the lower surface of the peripheral end portion of the lower sound absorbing layer 22 is sensitive to the upper surface of the peripheral end portion of the sound insulating layer 2. Pressure bonding (adhesion). As a result, as shown in FIG. 8, the space layer 4 is formed in the sound absorbing material 1, and the peripheral end portion of the space layer 4 is closed by the first closing portion 26 of the lower sound absorbing layer 22. The peripheral edge of the sound insulation layer 2 is exposed from the lower sound absorption layer 22.

  Subsequently, the upper sound absorbing layer 23 is disposed on the lower sound absorbing layer 22. Specifically, when the adhesive 24 is disposed on the lower surface of the upper sound absorbing layer 23, the lower surface of the central portion of the upper sound absorbing layer 23 is thermally bonded to the upper surface and side surfaces of the lower sound absorbing layer 22 by heat pressing. To do. At the same time, the lower surface of the peripheral end portion of the upper sound absorbing layer 23 is thermally bonded to the upper surface of the peripheral end edge of the sound insulating layer 2. By the above hot press, the adhesive 24 is melted and absorbed by the lower sound absorbing layer 22, whereby the lower sound absorbing layer 22 and the upper sound absorbing layer 23 are thermally bonded to each other. In addition, an adhesive layer 34 having a substantially flat rectangular frame shape is formed on the upper surface of the peripheral edge of the sound insulating layer 2.

<Effects of Second Embodiment>
Also according to the second embodiment, the same operational effects as those of the first embodiment can be obtained.

<Third Embodiment>
In the third embodiment, members and processes similar to those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the first embodiment, as shown in FIG. 3, the upper surface of the upper connecting wall 13 of the column member 8 is in direct contact with the lower surface of the sound absorbing layer 3.

  However, in the third embodiment, the upper surface of the upper connecting wall 13 and the lower surface of the sound absorbing layer 3 are not in direct contact, and the second sound insulating layer 10 is interposed therebetween.

  The second sound insulating layer 10 is interposed between the column member 8 (space layer forming member 7) and the sound absorbing layer 3. Thereby, the sound absorbing material 1 includes the sound insulating layer 2, the space layer forming member 7, the second sound insulating layer 10, and the sound absorbing layer 3 in this order.

  The second sound insulating layer 10 has a substantially porous plate (porous sheet) shape extending in the surface direction. The second sound insulating layer 10 has a plurality of through holes 25. Each of the plurality of through holes 25 penetrates the thickness direction of the second sound insulation layer 10. The plurality of through holes 25 face the upper space 15 of the space layer 4. As a result, the lower surface of the sound absorbing layer 3 exposed from the through hole 25 faces the upper space 15. The through hole 25 is a hole provided to improve the sound absorption and sound insulation by the second sound insulation layer 10. The through hole 25 has a shape such that the second sound insulating layer 10 is in direct contact with the upper connecting wall 13. That is, a portion other than the through hole 25 in the second sound insulating layer 10 corresponds to the upper connecting wall 13, and the through hole 25 corresponds to a portion other than the upper connecting wall 13 (specifically, the lower connecting wall 9). ing.

  The ratio (opening ratio) of the opening area of the through hole 25 to the area of the sound absorbing material 1 is, for example, 0.1% or more, preferably 1% or more, and, for example, 90% or less. When the opening ratio of the through holes is equal to or higher than the lower limit described above, the sound transmitted from the sound source 31 is transmitted to the column member 8, thereby exhibiting excellent sound insulation.

  The number of through holes 25 is not particularly limited, and is set so as to satisfy the above-described opening ratio.

  The surface density of the second sound insulating layer 10 is, for example, 0.01 or more, preferably 0.1 or more, and for example, 1 or less, preferably 0.5 or less. If the surface density of the second sound insulation layer 10 is equal to or greater than the above lower limit, the sound insulation can be improved. If the surface density of the second sound insulating layer 10 is equal to or less than the above upper limit, the sound absorbing material 1 can be reduced in weight.

  The Young's modulus E at 25 ° C. of the second sound insulating layer 10 is, for example, 10 GPa or more, preferably 50 GPa, and for example, 200 GPa or less, preferably 100 GPa or less. If the Young's modulus E of the second sound insulation layer 10 is equal to or greater than the lower limit described above, the column member 8 can be more reliably supported (fixed). If the Young's modulus E of the second sound insulating layer 10 is equal to or less than the above-described upper limit, the followability of the sound absorbing material 1 to the structure can be ensured.

  The second sound insulating layer 10 is made of, for example, a metal material such as aluminum, iron, or copper, for example, a resin material such as polyolefin (for example, polypropylene). Further, the second sound insulating layer 10 may be a single layer or a multi-layer laminate. The second sound insulating layer 10 is preferably a metal material, more preferably a metal plate (metal sheet) and a laminated plate (lamination) with a resin plate (resin sheet) from the viewpoint of securing a lightweight and high Young's modulus E. Sheet), and more preferably a laminate of a polyolefin plate and an aluminum plate.

  In order to provide the sound absorbing material 1 with the second sound insulating layer 10, for example, a method of fixing the second sound insulating layer 10 to the upper connection wall 13 of the column member 8 with an adhesive (pressure sensitive adhesive) (not shown), for example, a mesh shape A method in which the column member 8 is entangled and fixed to the second sound insulation layer 10 while being melted with heat, for example, the same composition as the column member 8 is laminated on the second sound insulation layer 10 in advance. Thereafter, there is a method of fixing the column member 8 and the second sound insulation layer 10 while welding them with heat.

<Modification of Third Embodiment>
In the third embodiment described above, as shown in FIG. 10, the second sound insulation layer 10 has a through hole 25.

  However, as shown in FIG. 11, in the sound absorbing material 1 of this modification, the second sound insulating layer 10 does not have the through hole 25.

  The second sound insulating layer 10 has a substantially plate shape (sheet) extending in the surface direction. An upper space 15 is formed by the second sound insulating layer 10, the inclined surface 14 of the inclined peripheral wall 12, and the lower connecting wall 9. The second sound insulating layer 10 is interposed between the upper space 15 and the sound absorbing layer 3.

  The surface density of the second sound insulation layer 10 according to the modification is, for example, 0.01 or more, preferably 0.1 or more, and for example, 1 or less, preferably 0.5 or less.

<Operational effects of the third embodiment>
When the second sound insulation layer 10 does not have the through hole 25 as in the modification shown in FIG. However, the third embodiment shown in FIG. 10 having the through hole 25 can maintain or improve the sound insulation and further the sound absorption as compared with the modification shown in FIG. 11 without the through hole 25. it can.

  As shown in FIG. 10, in the third embodiment, since the second sound insulating layer 10 has the through hole 25, it is lighter than the modification shown in FIG. 11 that does not have the through hole 25. Therefore, for example, it is suitable as a sound insulating material / sound absorbing material for vehicles, particularly as a sound insulating material / sound absorbing material for automobiles.

  Further, the column member 8 can be fixed (supported) by the second sound insulating layer 10. Therefore, the sound absorbing material 1 in a bent form can be provided by making the sound absorbing material 1 follow the structure, specifically, the structure of a vehicle, in particular, an automobile.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples.

  Moreover, the numerical value of the Example shown below can be substituted for the numerical value (namely, upper limit value or lower limit value) described in said embodiment.

1. Production of sound absorbing material 1 (Example corresponding to the first embodiment)
Example 1
First, as shown in FIG. 4, the sound insulation layer 2, the sound absorption layer 3, and the space layer formation member 7 were prepared, respectively.

  Specifically, a kneaded material containing a styrene-vinylisoprene copolymer and / EVA was prepared, and then the prepared kneaded material was extruded into a sheet shape to have a thickness of 1 mm, a lateral length of 150 mm, A pressure-sensitive adhesive layer having a length of 1000 mm in the front-rear direction was molded as the sound insulating layer 2.

  As the sound absorbing layer 3, an EPDM foam layer (Eptosealer No. 685, manufactured by Nitto Denko Corporation) having a thickness of 5 mm, a length in the left-right direction of 150 mm, and a length in the front-rear direction of 1000 mm was prepared.

  Furthermore, a core cone (also known as a single cone, manufactured by Ube Eximo Co., Ltd.) having a pillar member 8 having an inclined peripheral wall 12 and an upper connecting wall 13 and a lower connecting wall 9 and having the following dimensions is used as the space layer forming member 7. Prepared.

Thickness of the space layer forming member 7 (vertical length of the column member 8): 5 mm
The space layer forming member 7 has a length in the left-right direction of 100 mm and a length in the front-rear direction of 950 mm.
Angle formed by the inclined peripheral wall 12, the lower connecting wall 9 and the upper connecting wall 13: 63 degrees Diameter of the upper connecting wall 13: 2 mm
Diameter of the lower end of the inclined peripheral wall 12: 6 mm
Pitch in the left-right direction of the plurality of column members 8: 8 mm
The pitch in the front-rear direction between one column 16A and the other column 16B (see FIG. 2): 14 mm
Next, the space layer forming member 7 was arranged with the sound insulating layer 2 on the upper surface. Specifically, the lower surface of the lower connecting wall 9 was pressure-sensitive bonded to the upper surface of the central portion of the sound insulation layer 2 at a temperature of 130 degrees for 1 minute.

  Next, the sound absorbing layer 3 was disposed on the space layer forming member 7. Specifically, the lower surface of the peripheral end portion of the sound absorbing layer 3 was pressure-sensitive bonded to the upper surface of the peripheral end portion of the sound insulating layer 2 at a temperature of 130 degrees for 1 minute.

  Thus, the space layer 4 was formed, and the peripheral end portion of the space layer 4 was blocked by the blocking portion 19 of the sound absorbing layer 3.

  Thus, the sound absorbing material 1 was manufactured.

  The thickness T of the central portion of the sound absorbing material 1 was 11 mm. The thickness of the peripheral end portion of the sound absorbing material 1 was 8 mm.

Example 2
The sound absorbing material 1 is processed in the same manner as in Example 1 except that the space layer forming member 7 is formed not to include the lower connecting wall 9 but to include only the column members 8 arranged at the four corners of the sound insulating layer 2. Manufactured.

  The thickness T of the central portion of the sound absorbing material 1 was 11 mm. The thickness of the peripheral end portion of the sound absorbing material 1 was 8 mm.

Example 3
(Example corresponding to the second embodiment)
As shown in FIG. 8, the sound-absorbing layer 3 is formed of a lower sound-absorbing layer 22 and an upper sound-absorbing layer 23, and when the upper sound-absorbing layer 23 is disposed, it is hot-pressed and an EPDM foam layer having a thickness of 5 mm. The sound-absorbing material 1 was manufactured in the same manner as in Example 1 except that the second sound-absorbing layer 5 made of (Epto Sealer No. 685, manufactured by Nitto Denko Corporation) was provided. The total thickness T of the sound insulating layer 2, the sound absorbing layer 3, and the space layer forming member 7 at the center of the sound absorbing material 1 was 20.5 mm. The total thickness of the sound insulating layer 2, the sound absorbing layer 3, and the space layer forming member 7 at the peripheral end of the sound absorbing material 1 was 16 mm.

  Details of the lower sound-absorbing layer 22 and the upper sound-absorbing layer 23 and the conditions for hot pressing are described below.

Lower sound absorption layer 22: Foam layer made of polyurethane foam Lower sound absorption layer 22 thickness: 15 mm
Upper sound absorbing layer 23: DFK processed (resorcinol resin impregnated) fiber layer made of PET nonwoven fabric
: The fiber layer is made of PET and manufactured by the needle punch method.

                : On the lower surface of the fiber layer, an adhesive 24 formed into particles from an olefin-based hot-melt adhesive is disposed.

Upper sound absorbing layer 23 thickness: 0.5 mm
Hot press: temperature 180 degrees, pressure 0.4 MPa
Example 4
The sound-insulating layer 2 is prepared from an acrylic pressure-sensitive adhesive (double-sided tape, No. 512, manufactured by Nitto Denko), and further a second sound-absorbing layer comprising an EPDM foam layer (Epto Sealer No. 685, manufactured by Nitto Denko) having a thickness of 5 mm. 5 and the sound absorbing material 1 was manufactured in the same manner as in Example 1 except that the thickness of the space layer forming member 7 was 6 mm.

Example 5
(Example corresponding to the third embodiment)
The sound absorbing material 1 was manufactured in the same manner as in Example 4 except that the second sound insulating layer 10 having the through holes 25 was provided between the sound absorbing layer 3 and the column member 8.

  The second sound insulation layer 10 was a laminated plate of a 100 μm thick aluminum plate and a 40 μm thick polypropylene plate. The second sound insulation layer 10 was disposed so that the polypropylene plate was in direct contact with the upper connection wall 13 of the column member 8. Specifically, a laminated plate in which a polypropylene plate was laminated on an aluminum plate was heated and pressed to the column member 8 at 170 ° C. for 30 seconds. Moreover, the through-hole made the hole of diameter 1mm with a 10-mm pitch.

  The surface density of the second sound insulation layer 10 was 0.30. The opening ratio of the second sound insulating layer 10 was 1%. The Young's modulus of the second sound insulation layer 10 was 70 GPa.

Example 6
(Example corresponding to a modification of the third embodiment)
The sound-absorbing material 1 was manufactured in the same manner as in Example 5 except that the laminated plate did not have through holes.

  The surface density of the second sound insulation layer 10 was 0.31. The opening ratio of the second sound insulation layer 10 was 0%. The Young's modulus of the second sound insulation layer 10 was 70 GPa.

Comparative Example 1
A sound absorbing material 1 having a thickness of 5 mm was manufactured in the same manner as in Example 1 except that the space layer forming member 7 was not disposed.

  That is, the sound absorbing material 1 was manufactured without the space layer forming member 7, that is, without the space layer 4, and including the sound insulating layer 2 and the sound absorbing layer 3 pressure-sensitively bonded to the entire upper surface of the sound insulating layer 2.

  The total thickness T of the sound insulating layer 2 and the sound absorbing layer 3 in the sound absorbing material 1 was 6 mm.

Comparative Example 2
A sound absorbing material 1 having a thickness of 15.5 mm was manufactured in the same manner as in Example 3 except that the space layer forming member 7 and the second sound absorbing layer 5 were not disposed.

  That is, the sound absorbing material 1 was manufactured without the space layer forming member 7, that is, without the space layer 4, and including the sound insulating layer 2 and the sound absorbing layer 3 pressure-sensitively bonded to the entire upper surface of the sound insulating layer 2.

  The total thickness T of the sound insulating layer 2 and the sound absorbing layer 3 in the sound absorbing material 1 was 16.5 mm.

Comparative Example 3
The sound absorbing layer 3 (EPDM foam layer) having a thickness of 5 mm in Example 1 was prepared as the sound absorbing material 1.

Comparative Example 4
A sound absorbing layer 3 having a thickness of 40 mm provided with the lower sound absorbing layer 22 (polyurethane foam) and the upper sound absorbing layer 23 (DFK-processed PET nonwoven fabric) in Example 3 was prepared as the sound absorbing material 1.

Comparative Example 5
A space layer forming member 7 (core cone) having a thickness of 5 mm in Example 1 was prepared as the sound absorbing material 1.

Comparative Example 6
A sound absorbing layer 3 having a thickness of 20 mm made of a fiber layer (trade name “Sound Block”, manufactured by Toyobo Co., Ltd.) was prepared as the sound absorbing material 1.

Comparative Example 7
A sound absorbing layer 3 having a thickness of 82 mm made of a foam layer (polyurethane foam manufactured by INOAC) was prepared as the sound absorbing material 1.

2. Evaluation (1) Normal incidence sound absorption coefficient According to JISA1405-1 (measurement of sound absorption coefficient and impedance by an acoustic tube—Part 1: standing wave ratio method), normal incidence sound absorption coefficient of each example and each comparative example was measured.

  The results are shown in FIG.

  Note that the higher the numerical value of the normal incident sound absorption coefficient, the better the sound absorption.

(2) Transmitted sound insertion loss The transmitted sound insertion loss of each example and each comparative example was measured according to JIS A 1441-1-2007 (the air sound blocking performance of buildings and building members by the sound intensity method).

  The result is shown in FIG.

  The transmitted sound insertion loss indicates that the higher the numerical value, the better the sound insulation.

3. Discussion (1) As can be seen from FIG. 12 and Table 1, Examples 1 to 3 including the sound insulating layer 2, the sound absorbing layer 3 and the space layer 4 are compared with Comparative Examples 1 to 3, 5 and 6 which do not include the space layer 4. In comparison, the sound absorption is excellent at a frequency of 1000 Hz in a low frequency region (corresponding to a road noise of a frequency of 800 Hz or more and 1000 Hz or less).

  On the other hand, Comparative Examples 4 and 7 did not include the space layer 4, but had good sound absorption at a frequency of 1000 Hz in the low frequency region. However, each of the sound absorbing materials 1 of Comparative Examples 4 and 7 has a thickness of 40 mm and 82 mm, which is unsuitable for downsizing (thinning).

  Moreover, Example 1 provided with the truncated cone-shaped column member 8 having the inclined surface 14 does not have the inclined surface 14 and has a higher frequency region (frequency 2000 Hz) than the Example 2 provided with the columnar column member 8. The sound absorption is excellent at a frequency of 3500 Hz within the above range (corresponding to an engine sound of 4000 Hz or less).

  (2) As can be seen from FIG. 13 and Table 1, Examples 1, 3 and 4 including the sound insulating layer 2, the sound absorbing layer 3 and the space layer 4 are compared with Comparative Examples 1 to 3 and 5 which do not include the space layer 4. Thus, the sound insulation at a frequency of 1000 Hz in a low frequency region (corresponding to a road noise of a frequency of 800 Hz or more and 1000 Hz or less) is excellent.

  On the other hand, Comparative Example 7 did not include the spatial layer 4, but had good sound insulation at a frequency of 1000 Hz in the low frequency region. However, the sound-absorbing material 1 of Comparative Example 7 was as thick as 82 mm and was unsuitable for downsizing (thinning).

  Further, as can be seen from FIG. 13 and Table 1, Example 6 having no through hole 25 has low sound insulation in the low frequency region (corresponding to road noise of frequency 800 Hz or more and 1000 Hz or less). Compared with Example 6, Example 5 which has the through-hole 25 is excellent in the above-mentioned sound-insulating property in the low frequency region.

DESCRIPTION OF SYMBOLS 1 Sound-absorbing material 2 Sound-insulating layer 3 Sound-absorbing layer 4 Spatial layer 8 Column member 10 Second sound-insulating layer 14 Inclined surface 19 Blocking portion 22 Lower sound-absorbing layer 23 Upper sound-absorbing layer 25 Through-hole 26 First blocking portion 27 Second blocking portion T Thickness ( Total thickness of sound insulation layer, sound absorption layer and space layer forming member)

Claims (7)

A sound absorbing layer,
A sound insulating layer disposed on one side in the thickness direction of the sound absorbing layer;
A sound absorbing material, comprising: a space layer that separates the sound absorbing layer and the sound insulating layer in the thickness direction. A plurality of pillar members that extend in the thickness direction and are spaced apart from each other in a direction orthogonal to the thickness direction;
The sound absorbing material according to claim 1, wherein the plurality of column members are disposed between the sound absorbing layer and the sound insulating layer. A second sound insulation layer interposed between the column member and the sound absorbing layer;
The sound absorbing material according to claim 2, wherein the second sound insulating layer has a surface density of 0.01 or more.   4. The sound absorbing material according to claim 2, wherein each of the plurality of column members has an inclined surface that is inclined with respect to the thickness direction. 5.   5. The sound-absorbing material according to claim 4, wherein each of the plurality of pillar members has a substantially conical shape whose cross-sectional area increases toward one side in the thickness direction.   The sound absorbing material according to claim 1, further comprising a closing portion that closes a peripheral end portion of the space layer.   The sound absorbing material according to claim 6, wherein the blocking portion is a peripheral end portion of the sound absorbing layer.

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