JP6753673B2 - Sound absorbing material - Google Patents

Description

The present invention relates to a sound absorbing material.

Conventionally, it has been 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 a polyurethane foam has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2008-32977

However, in the sound absorbing material described in Patent Document 1, the sound absorbing material is thickly molded 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 become large.

On the other hand, if the sound absorbing material described in Patent Document 1 is thinly molded, 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 molded sound absorbing material have a problem that they have almost no sound insulation.

An object of the present invention is to provide a sound absorbing material having excellent 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 having sound insulation.

The present invention (1) comprises a sound absorbing material including a sound absorbing layer, a sound insulating layer arranged on one side of the sound absorbing layer in the thickness direction, and a space layer separating the sound absorbing layer and the sound insulating layer in the thickness direction. Including.

Since this sound absorbing material includes a space 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 space layer in the direction orthogonal to the thickness direction to attenuate the sound. ..

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

Further, since the sound absorbing material may be composed of the sound absorbing layer, the sound insulating layer and the space layer so that the sound in the low frequency region can be dispersed in the space layer in the orthogonal direction, the thickness of the sound absorbing material can be reduced. ..

Further, 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 arranged at intervals in a direction orthogonal to the thickness direction, and the plurality of pillar members include the sound absorbing layer and the sound insulating layer. Includes the sound absorbing material according to (1), which is arranged between and.

In this sound absorbing material, a plurality of pillar members extending in the thickness direction and arranged at intervals in the direction orthogonal to the thickness direction are arranged between the sound absorbing layer and the sound insulating layer, so that a spatial layer is surely formed. can do. In addition, the sound dispersed in the orthogonal direction can be scattered by the plurality of pillar members.

The present invention (3) further includes a second sound insulation layer interposed between the pillar member and the sound absorbing layer, and the second sound insulation layer has a surface density of 0.01 or more, according to (2). Includes the described sound absorbing materials.

Since this sound absorbing material further includes a second sound insulating layer having a surface density equal to or higher than the above-mentioned lower limit, excellent sound absorbing and sound insulating properties can be ensured while reducing the weight.

In addition, the pillar member can be supported by the second sound insulation layer. It is possible to provide a sound absorbing material in a bent form by making the sound absorbing material follow the structure.

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

According to this sound absorbing material, in the space layer, the sound incident along the thickness direction can be scattered in the direction intersecting both the thickness direction and the orthogonal direction by the inclined surface inclined with respect to the thickness direction. Therefore, the sound absorption 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 pillar members has a substantially conical shape in which the cross-sectional area increases toward one side in the thickness direction.

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

The present invention (6) includes the sound absorbing material according to any one of (1) to (5), further including a closing portion that closes the peripheral end portion of the space layer.

According to this sound absorbing material, the sound dispersed in the direction orthogonal to the thickness direction by the closing portion can be trapped by the closing portion. Therefore, the sound absorption property of the sound absorbing material can be improved.

In the present invention (7), the closed portion includes the sound absorbing material according to (6), which is a peripheral end portion of the sound absorbing layer.

When a closing member is separately provided to close the peripheral end of the space layer, the configuration becomes complicated.

However, in this sound absorbing material, since the peripheral end portion of the sound absorbing layer is used as a closing 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 having excellent sound absorbing properties in a low frequency region. The sound absorbing material of the present invention has excellent sound insulation.

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

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

In FIG. 3, the vertical direction of the paper surface is the vertical 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) and below the paper surface. The side is the lower side (one side in the thickness direction, one side in the first direction). The left-right direction of the paper surface is a direction orthogonal to the vertical direction (second direction), the left side of the paper surface is the left side (one side of the second direction), and the right side of the paper surface is the right side (the other side of the second direction). The paper thickness direction is the front-back direction (direction orthogonal to the vertical and horizontal directions, the third direction), and the front side of the paper is the front side (one side of the third direction), and the back side of the paper is the rear side (the other in the third direction). Side).

In FIG. 2, the sound absorbing layer (described later) is omitted in order to clearly show the shape of the pillar member. Further, in FIGS. 3 to 9, in order to clearly show the cross-sectional shape of the space layer forming member (described later), the scale, the aspect ratio, and the like are appropriately changed from those of the actual one for convenience.

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 arranged 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. A space layer forming member 7 arranged between the sound absorbing layer 3 and the sound absorbing layer 3 is provided.

The sound insulation 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 layered shape) having an outer shape corresponding to the outer shape of the sound absorbing material 1 in a plan view. The sound insulation layer 2 is not particularly limited as long as it can insulate sound.

In the sound insulation, when the sound absorbing material 1 is arranged in the middle of the propagation direction in which the sound is propagated from the sound source 31 shown by the virtual line in FIG. 3, the sound is blocked by the sound insulation layer 2 and thereby transmitted through the sound insulation layer 2. It is an action (role) that effectively prevents propagation to the downstream side (lower side in FIG. 3) in the propagation direction after (passing) or detouring. The sound insulation layer 2 and the sound insulation property are the members and properties capable of sound insulation.

Examples of the sound insulation layer 2 include a pressure-sensitive adhesive layer (adhesive layer) formed in a layer (sheet) shape from the pressure-sensitive adhesive composition.

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

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

Examples of the rubber component 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 thereof include isoprene copolymer and natural rubber. The rubber component can be used alone or in combination. Preferred examples of the rubber component include EVA and a styrene-vinyl isoprene copolymer. These can be used alone or in combination.

Examples of the tackifier resin include rosin-based resin, terpene-based resin, aliphatic resin, aromatic resin, alicyclic resin, and kumaron-inden resin. The tackifier resin can be used alone or in combination. As the tackifier resin, an aliphatic resin is preferable.

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

Examples of the filler include calcium carbonate, silica and the like. 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 blending 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 blending ratio of the tackifier 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 the additive is, for example, more than 10% by mass and, for example, 70% by mass or less, and the blending ratio of the additive in the pressure-sensitive adhesive composition is, for example, 1% by mass or more, for example, 5% by mass. % Or less.

In order to obtain the sound insulation layer 2, for example, a kneaded product is prepared by first 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 of 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 it can insulate sound.

As shown in FIG. 3, when the sound absorbing material 1 is arranged in the middle of the propagation direction in which the sound is propagated from the sound source 31, the sound is absorbed by the sound absorbing layer 3 and thereby from the sound absorbing layer 3. It is an action (role) that effectively prevents reflection (backward) to the upstream side (upper side in FIG. 3) in the propagation direction. The sound absorbing layer 3 and the sound absorbing property are the members and properties capable of absorbing 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 multiple layers. 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 insulation layer 2 (more specifically, pressure-sensitive adhesion). 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 the space layer 4 described below. That is, the sound absorbing layer 3 is formed in a shape that bulges upward from the peripheral end portion toward the central portion (a substantially U-shaped cross section or a substantially hat-shaped cross section that opens downward). There is.

Examples of the foam layer include polyurethane foam, EPDM foam, polystyrene foam, polyolefin foam, chloroprene foam, polyester foam, and the like. EPDM foams and polyurethane foams are preferred.

The foamed layer has, for example, a continuous cell structure in which a plurality of bubbles communicate with each other (continuous bubble structure), for example, a closed cell structure containing a plurality of bubbles independently (single bubble structure), for example, a semi-continuous semi-closed cell structure. Has. From the viewpoint of sound absorption, the foam layer preferably has an open cell structure or a semi-continuous semi-closed cell structure.

As the foam layer, a commercially available product can be used, and specifically, an ept sealer (EPDM foam, manufactured by Nitto Denko KK) or the like is used.

Examples of the fiber layer include non-woven fabrics and woven fabrics, and preferably non-woven fabrics.

Examples of the non-woven fabric include polyester non-woven fabrics such as PET non-woven fabrics, for example, polyolefin non-woven fabrics such as polypropylene non-woven fabrics, for example, nylon non-woven fabrics, for example, non-woven fabrics made of a mixture of polyester and rayon. As the non-woven fabric, a polyester non-woven fabric is preferable.

The non-woven fabric is produced by, for example, a needle punch method, a chemical bond method, a spun bond method, or the like. The non-woven fabric is preferably produced by a needle punching method, a chemical bond method, and more preferably a needle punching method.

Further, the fiber layer may be impregnated with a thermosetting resin. As the fiber layer, a non-woven fabric impregnated with a thermosetting resin is preferable.

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

A commercially available product can be used as the fiber layer, and specifically, a DFK-processed non-woven fabric (trade name, manufactured by Nagoya Yuka Co., Ltd.) or the like is used as the non-woven fabric impregnated with the thermosetting resin.

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-back direction, and is formed smaller than the sound insulating layer 2 and the sound absorbing layer 3 in a plan view. That is, as shown in FIGS. 2 and 3, the space layer forming member 7 is provided inside the peripheral end portion of the sound insulation layer 2, and the upper surface of the peripheral end portion of the sound insulation layer 2 is the circumference 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 integrally includes a pillar member 8 and a lower connecting wall 9.

A plurality of pillar 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 column rows 16 which are arranged in a plurality of columns at intervals in the left-right direction. ing. Further, a plurality of column rows 16 are arranged in a row in the front-rear direction. The plurality of column rows 16 are arranged in a discrepancy in the front-rear direction. That is, in detail, each column member 8 in one column 16 (16A) is each in another column 16 (16B) behind the one column 16 (16A) when projected in the front-rear direction. It is arranged so as to be offset from the pillar member 8.

As shown in FIGS. 1 and 3, each of the plurality of column members 8 is formed in a substantially conical shape, specifically, a truncated cone shape in which the cross-sectional area increases toward the lower side. Each of the plurality of column members 8 integrally includes 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 in the vertical direction (specifically, the vertical direction, the horizontal direction, and the front-rear direction). Specifically, the inclined peripheral wall 12 has a larger opening cross-sectional area along the left-right direction and the front-back direction toward the lower side, and has 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-back direction. In, it is 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 disk 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 pillar 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 insulation layer 2.

Examples of the material for forming the space layer forming member 7 include resins, and specific examples thereof include thermoplastic resins. Examples of the thermoplastic resin include olefin resins (for example, polyethylene, polypropylene, or copolymers thereof), polycarbonates, polyesters, polystyrenes, acrylic resins, and the like. An olefin resin is preferable, and polypropylene is more preferable.

The dimensions of the space layer forming member 7 are appropriately set, and the vertical length of each of the plurality of pillar members 8 is, for example, 1 mm or more, preferably 3 mm or more, and for example, 100 mm or less, preferably 100 mm or less. It is 50 mm or less. The angle formed by the inclined peripheral wall 12 of each of the plurality of column members 8 and 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 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 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 of the column members 8 in the left-right direction and the length between the column members 8 arranged adjacent to each other in the left-right direction) is, for example, 1 mm or more, preferably 3 mm or more. Yes, and for example, it is 50 mm or less, preferably 20 mm or less. The pitch of the plurality of columns 16 in the front-rear direction 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 pillar member 8.

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

Further, as the space layer forming member 7, a commercially available product can be used, and specifically, a core cone series (also known as a single cone, manufactured by Ube Exsymo Co., Ltd.) is used.

Then, since the space layer forming member 7 described above is arranged between the sound insulation layer 2 and the sound absorbing layer 3, the space layer 4 is formed between the sound insulation 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 from the upper space 15 and the lower space 18.

The upper space 15 is a space that extends in the left-right direction and the front-back 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 pillar members 8. Specifically, the upper space 15 includes the lower surface of the central portion of the sound absorbing layer 3 (excluding the portion in contact with the upper connecting wall 13), the outer peripheral surface of the inclined peripheral wall 12 (inclined surface 14), and the lower connecting wall 9. It is separated from the upper surface. Further, the peripheral ends of the upper space 15 (both ends in the left-right direction and both ends in the front-rear direction) 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 the closing portion 19.

The lower space 18 is a plurality of closed spaces formed corresponding to each of the plurality of pillar members 8 on the lower side of each inclined peripheral wall 12 and the upper connecting wall 13 of the plurality of pillar members 8. Specifically, each of the plurality of lower spaces 18 excludes the inner peripheral surface of the inclined peripheral wall 12, the lower surface of the upper connecting wall 13, and the upper surface of the central portion of the sound insulation layer 2 (excluding the portion in contact with the lower connecting wall 9). ).

The thickness T at the central portion of the sound absorbing material 1 (that is, the total thickness T at the central portion 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, preferably 50 mm or less. It is 30 mm or less, and is, for example, 5 mm or more. When the thickness T is not more than the above upper limit, the sound absorbing material 1 can be made thinner. The thickness of the sound absorbing material 1 at the peripheral end is the total thickness of the sound insulating layer 2 and the sound absorbing layer 3, for example, 1 mm or more, preferably 2 mm or more, and for example, 50 mm or less, preferably 30 mm or less. Is.

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

First, in this method, as shown in FIG. 4, the sound insulation layer 2, the sound absorption layer 3, and the space layer forming member 7 are prepared, respectively.

The sound insulation layer 2 and the sound absorption layer 3 are prepared with the same dimensions in a plan view. When the sound insulation 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 insulation layer 2.

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

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

At this time, when the sound insulation layer 2 is formed from the pressure-sensitive adhesive layer (adhesive layer), the lower surface of the lower connecting wall 9 is pressure-sensitively adhered (adhesive) to the upper surface of the central portion of the sound insulation layer 2. Preferably, the lower surface of the lower connecting wall 9 and the upper surface of the central portion of the sound insulation layer 2 are pressure-sensitively adhered (adhesive) while being heated.

Next, the sound absorbing layer 3 is arranged on the space layer forming member 7 so that the peripheral end portion thereof contacts the peripheral end portion of the sound insulation layer 2. Specifically, when the sound insulation 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 insulation layer 2. Adhere (adhesive). As a result, as shown in FIG. 3, the space layer 4 is formed between the sound insulation layer 2 and the sound absorbing layer 3, and the peripheral end portion of the space layer 4 is closed by the closing portion 19 of the sound absorbing layer 3.

As a result, the sound absorbing material 1 is manufactured.

When the sound absorbing material 1 is used, the peeling layer (not shown) laminated on the lower surface of the sound insulating layer 2 is peeled off from the sound insulating layer 2 if 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 place where noise including sound in a low frequency region passes. Specifically, the sound absorbing material 1 is installed in various structures so 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. To.

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

Further, 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 region is, for example, 2000 Hz or higher, further 2500 Hz or higher, further 3000 Hz or higher, and for example, 4000 Hz or lower noise.

<Action and effect of the first embodiment>
Since the sound absorbing material 1 includes a space layer 4 that separates the central portion of the sound absorbing layer 3 and the central portion of the sound insulating layer 2 in the thickness direction (vertical direction), the sound in the low frequency region can be heard in the space layer 4. Sound can be attenuated by distributing it in the left-right direction and the front-back direction.

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

Further, 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 space layer 4 in the left-right direction and the front-back direction, the central portion of the sound absorbing material 1 The thickness T of the can be reduced.

Further, in the sound absorbing material 1, a plurality of pillar members 8 extending in the vertical direction and arranged at intervals in the horizontal direction and the front-rear direction are arranged 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 the sound dispersed in the left-right direction and the front-back 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 space layer 4, the sound incident downward from the sound source 31 indicated by the virtual line is transmitted in the vertical direction and the surface direction (horizontal direction and in the horizontal direction) by the inclined surface 14 inclined in the vertical direction. It can be scattered in a direction that intersects both directions (front-back direction), that is, in the left-right direction, front-back direction, and 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 space layer 4, the sound incident downward from the sound source 31 is intersected in both the vertical direction and the surface direction by the inclined surfaces 14 of the plurality of pillar members 8, that is, , It can be scattered well in the left-right direction, the front-back 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 by the closing portion 19 can be effectively trapped by the closing portion 19. Therefore, the sound absorbing property of the sound absorbing material 1 can be improved.

<Modified example of the first embodiment>
In the above-described first embodiment, as shown in FIGS. 1 and 2, the sound absorbing material 1 is formed in a substantially rectangular shape in a plan view, but the plan view shape is not particularly limited. The shape of the sound absorbing material 1 may be formed into an appropriate plan view shape corresponding to the shape of various structures to be installed. For example, a plan view substantially circular shape, a plan view substantially elliptical shape, and a plan view substantially triangular shape may be formed. It can be formed into an appropriate plan view shape such as a shape and a substantially pentagonal shape in a 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, but for example, as shown by the virtual line in FIG. 3, the lower surface of the sound insulation layer 2 is exposed to the second sound absorption. It can also be coated with layer 5.

As shown by the virtual line in FIG. 3, the second sound absorbing layer 5 is arranged on the lower surface of the sound insulating layer 2. The second sound absorbing layer 5 is formed in a flat plate shape (or layered shape) having an outer shape corresponding to the outer shape of the sound insulation layer 2. The second sound absorbing layer 5 is a layer that insulates the sound leaked from the sound insulating layer 2.

Examples of the second sound absorbing layer 5 include layers similar to the foam layer, fiber layer, and the like mentioned in the sound absorbing layer 3, preferably a foam layer.

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

In order to manufacture the sound absorbing material 1 provided with the second sound absorbing layer 5, first, the second sound absorbing layer 5 is prepared, and then the sound insulating layer 2 is provided with the second sound absorbing layer 5 so as to refer to the virtual line in FIG. The space layer forming member 7 and the sound absorbing layer 3 are then laminated in the same manner as in the above-described first embodiment.

The second sound absorbing layer 5 can improve the sound insulating property of the sound absorbing material 1.

Further, in the above-described first embodiment, as shown in FIG. 3, each of the plurality of pillar members 8 is formed in a truncated cone shape, but the shape of the pillar 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.

Even with this modification, the same effect as that of the first embodiment described above can be obtained.

Further, in the above-described first embodiment, as shown in FIG. 3, each of the plurality of column members 8 is formed in a substantially truncated cone shape having an inclined surface 14, but as shown in FIG. 6, for example. It can also be formed into a substantially cylindrical shape having no inclined surface 14.

As shown in FIG. 6, each of the plurality of pillar members 8 is formed so as to extend in the vertical direction. That is, the peripheral surface 44 of the pillar member 8 extends in the vertical direction. The thickness of the column member 8 (maximum thickness in the direction orthogonal 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.

Further, in the above description of FIG. 5, each of the plurality of pillar members 8 is formed in a substantially cylindrical shape, but each of the plurality of pillar members 8 may extend in the vertical direction, for example, although not shown. , Each of the plurality of pillar members 8 can be formed into a substantially polygonal shape such as a substantially triangular prism shape, a substantially square pillar shape, and a substantially hexagonal column shape.

Further, as shown by the virtual line in FIG. 6, a warped portion 17 can be formed at the upper end portion of the column member 8. The warped portion 17 is formed in a shape of warping (changing) from the upper end portion of the pillar member 8 in one of the lower diagonally left-right directions or the lower diagonally front-rear direction. The warped portion 17 is integrally formed with the column member 8, so that the material and the thickness of the warped portion 17 are the same as those of the column member 8.

The number of pillar members 8 is not particularly limited. Further, the space layer forming member 7 can be formed without providing the lower connecting wall 9. That is, for example, although not shown, the space layer forming member 7 may not include the lower connecting wall 9, but may include only four pillar members 8 erected at the four corners of the sound insulation layer 2.

Further, in the above-described first embodiment, as shown in FIGS. 2 and 3, the space layer forming member 7 is formed 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 lower surface of the sound insulating layer 2 is pressure-sensitively adhered to the upper surface of the peripheral end portion of the sound insulating layer 2, thereby forming the peripheral end portion of the sound absorbing layer 3 as the closing portion 19. However, as shown in FIG. 7, the space layer forming member 7 can be formed to have the same dimensions as the sound insulating layer 2 and the sound absorbing layer 3, and the sound absorbing material 1 can be formed without forming the closing portion 19.

In that case, as shown in FIG. 7, a closing member 45 made of a foam layer, a fiber layer, or the like is separately arranged so as to cover the peripheral ends of 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, for example, in a substantially U-shape in cross-sectional view.

Preferably, the closing member 45 (see FIG. 7) is not separately provided, and as shown in FIG. 1, the peripheral end portion of the sound absorbing layer 3 is designated as the closing portion 19. 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 processes as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be 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 plurality of layers 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 layered shape, and is formed in a shape larger than the space layer forming member 7 and smaller than the sound insulating layer 2 in a 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 connecting 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. It is in contact with the upper surface of the surface (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 closed portion 26.

Examples of the lower sound absorbing layer 22 include the above-mentioned foamed layer. 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 of the sound absorbing material 1. The upper sound absorbing layer 23 has a layered 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 the 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 the sound insulating layer 2 exposed from the upper sound absorbing layer 23. It is in contact with the upper surface of the (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 the second closed portion 27.

Examples of the upper sound absorbing layer 23 include the above-mentioned fiber layer. 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, and further. For example, it is 5 mm or more, and at the peripheral end, for example, 60 mm or less, more preferably 50 mm or less, preferably 30 mm or less, and for example, 1 mm or more.

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

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

The adhesive 24 can be arranged in advance on the lower surface of the upper sound absorbing layer 23. The adhesive 24 is formed in the form of particles from, for example, an olefin-based hot-melt adhesive.

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

Next, the lower sound absorbing layer 22 is arranged on the space layer forming member 7 so that the peripheral end portion thereof contacts the peripheral end portion of the sound insulation layer 2. Specifically, when the sound insulation 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 felt by the upper surface of the peripheral end portion of the sound insulation layer 2. Pressure adhesion (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 arranged on the lower sound absorbing layer 22. Specifically, when the adhesive 24 is arranged 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 heat-bonded to the upper surface and the side surface of the lower sound absorbing layer 22 by a heat press. To do. At the same time, the lower surface of the peripheral end portion of the upper sound absorbing layer 23 is heat-bonded to the upper surface of the peripheral end edge of the sound insulating layer 2. By the above heat 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 adhered to each other. Further, an adhesive layer 34 having a substantially flat rectangular frame shape is formed on the upper surface of the peripheral edge of the sound insulation layer 2.

<Action and effect of the second embodiment>
The second embodiment can also have the same effects as those of the first embodiment.

<Third Embodiment>
In the third embodiment, the same members and processes as those in the first and second embodiments are designated by the same reference numerals, and detailed description thereof will be 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 do not come into direct contact with each other, and the second sound insulating layer 10 is interposed between them.

The second sound insulation layer 10 is interposed between the pillar member 8 (spatial layer forming member 7) and the sound absorbing layer 3. As a result, 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 insulation layer 10 has a substantially perforated plate (perforated sheet) shape extending in the plane direction. Further, the second sound insulation layer 10 has a plurality of through holes 25. Each of the plurality of through holes 25 penetrates in 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. Further, the through hole 25 is a hole provided in order to improve the sound absorption property and the sound insulation property of the second sound insulation layer 10. The through hole 25 has a shape so that the second sound insulation layer 10 is in direct contact with the upper connecting wall 13. That is, in the second sound insulation layer 10, the portion other than the through hole 25 corresponds to the upper connecting wall 13, and the through hole 25 corresponds to the 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 hole is equal to or higher than the above lower limit, excellent sound insulation can be exhibited by transmitting the sound propagated from the sound source 31 to the pillar member 8.

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

The surface density of the second sound insulation 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 at least the above lower limit, the sound insulation can be improved. If the surface density of the second sound insulation layer 10 is equal to or less than the above upper limit, the weight of the sound absorbing material 1 can be reduced.

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

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

In order to provide the second sound insulating layer 10 in the sound absorbing material 1, for example, a method of fixing the second sound insulating layer 10 to the upper connecting wall 13 of the pillar member 8 with an adhesive (pressure sensitive adhesive) (not shown), for example, a mesh shape. A method of entwining and fixing the pillar member 8 with the second sound insulation layer 10 while melting the pillar member 8 with heat, for example, the same composition as the pillar member 8 is laminated in advance on the second sound insulation layer 10. After that, there is a method of fixing the pillar member 8 and the second sound insulation layer 10 while welding them by 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 modified example, the second sound insulating layer 10 does not have the through hole 25.

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

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

<Action and effect of the third embodiment>
When the second sound insulation layer 10 does not have the through hole 25 as in the modified example shown in FIG. 11, the sound insulation property may decrease. However, the third embodiment shown in FIG. 10 having the through hole 25 can maintain or improve the sound insulation property and the sound absorption property as compared with the modified example shown in FIG. 11 having no through hole 25. it can.

Further, as shown in FIG. 10, in the third embodiment, since the second sound insulation layer 10 has the through hole 25, it is lighter than the modified example shown in FIG. 11 which 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 pillar member 8 can be fixed (supported) by the second sound insulation layer 10. Therefore, it is possible to provide the sound absorbing material 1 in a bent form by making the sound absorbing material 1 follow the structure of a structure, specifically, a vehicle, particularly an automobile.

Examples and comparative examples are shown below, and the present invention will be described in more detail, but the present invention is not limited thereto.

Further, the numerical values of the examples shown below can be replaced with the numerical values (that is, the upper limit value or the lower limit value) described in the above-described embodiment.

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

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

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

Further, a core cone (also known as a single cone, manufactured by Ube Exsymo Co., Ltd.), which is provided with a pillar member 8 having an inclined peripheral wall 12 and an upper connecting wall 13 and a lower connecting wall 9 and has the following dimensions, is used as a space layer forming member 7. I prepared it.

Thickness of space layer forming member 7 (length of pillar member 8 in the vertical direction): 5 mm
The space layer forming member 7 has a length of 100 mm in the left-right direction and a length of 950 mm in the front-rear direction.
Angle formed by the inclined peripheral wall 12 and 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
Left-right pitch of the plurality of pillar members 8: 8 mm
Pitch of one column 16A and another column 16B in the front-rear direction (see FIG. 2): 14 mm
Next, the space layer forming member 7 was arranged on the upper surface of the sound insulation layer 2. Specifically, the lower surface of the lower connecting wall 9 was pressure-sensitively adhered to the upper surface of the central portion of the sound insulation layer 2 at a temperature of 130 ° C. for 1 minute.

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

As a result, the space layer 4 was formed, and the peripheral end portion of the space layer 4 was closed by the closing portion 19 of the sound absorbing layer 3.

As a result, 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 space layer forming member 7 is treated in the same manner as in the first embodiment except that the space layer forming member 7 is formed so as to include only the pillar members 8 arranged at the four corners of the sound insulation layer 2 without the lower connecting wall 9, and the sound absorbing material 1 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 from the lower sound absorbing layer 22 and the upper sound absorbing layer 23, and when the upper sound absorbing layer 23 is arranged, it is heat-pressed and further, an EPDM foam layer having a thickness of 5 mm is formed. The sound absorbing material 1 was produced in the same manner as in Example 1 except that the second sound absorbing layer 5 made of (Ept Sealer No. 685, manufactured by Nitto Denko KK) was provided. The total thickness T of the sound insulating layer 2, the sound absorbing layer 3, and the space layer forming member 7 in the central portion 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.

The details of the lower sound absorbing layer 22 and the upper sound absorbing layer 23 and the conditions of the hot press are described below.

Lower sound absorbing layer 22: Foamed layer made of polyurethane foam Thickness of lower sound absorbing layer 22: 15 mm
Upper sound absorbing layer 23: Fiber layer made of DFK processed (resorcinol resin impregnated) PET non-woven fabric
: The fiber layer consists of PET and is manufactured by the needle punching method.

: An adhesive 24 formed in particles from an olefin-based hot melt type adhesive is arranged on the lower surface of the fiber layer.

Thickness of upper sound absorbing layer 23: 0.5 mm
Heat press: temperature 180 degrees, pressure 0.4 MPa
Example 4
The sound insulation layer 2 is prepared from an acrylic adhesive (double-sided tape, No. 512, manufactured by Nitto Denko), and further, a second sound absorbing layer made of an EPDM foam layer (Ept Sealer No. 685, manufactured by Nitto Denko) having a thickness of 5 mm. The sound absorbing material 1 was manufactured in the same manner as in Example 1 except that 5 was provided and 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 hole 25 was provided between the sound absorbing layer 3 and the pillar member 8.

The second sound insulation layer 10 was a laminated plate of an aluminum plate having a thickness of 100 μm and a polypropylene plate having a thickness of 40 μm. The second sound insulation layer 10 was arranged so that the polypropylene plate was in direct contact with the upper connecting wall 13 of the pillar member 8. Specifically, a laminated plate in which a polypropylene plate was laminated on an aluminum plate was heat-pressed and adhered to a pillar member 8 at 170 ° C. for 30 seconds. Further, as the through hole, a hole having a diameter of 1 mm was drilled at a pitch of 10 mm.

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

Example 6
(Example corresponding to the modified example of the third embodiment)
The sound absorbing material 1 was produced by treating the laminated plate 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 produced by treating in the same manner as in Example 1 except that the space layer forming member 7 was not arranged.

That is, a sound absorbing material 1 is manufactured which does not include the space layer forming member 7, that is, does not include the space layer 4, and includes the sound insulating layer 2 and the sound absorbing layer 3 which is pressure-sensitively adhered 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 produced by treating 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 arranged.

That is, a sound absorbing material 1 is manufactured which does not include the space layer forming member 7, that is, does not include the space layer 4, and includes the sound insulating layer 2 and the sound absorbing layer 3 which is pressure-sensitively adhered 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
The 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 non-woven fabric) in Example 3 was prepared as the sound absorbing material 1.

Comparative Example 5
The 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 and 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 and made of a foam layer (polyurethane foam manufactured by Inoac Corporation) was prepared as the sound absorbing material 1.

2. Evaluation (1) Vertically incident sound absorption coefficient The vertically incident sound absorption coefficient of each Example and each Comparative Example was measured according to JIS A1405-1 (Measurement of sound absorption coefficient and impedance by acoustic tube-Part 1: Standing wave ratio method).

The results are shown in FIG. 12 and Table 1.

It should be noted that the higher the value of the vertical incident sound absorption coefficient, the better the sound absorption property.

(2) Transmission loss Insertion loss The transmission sound insertion loss of each Example and each Comparative Example was measured according to JIS A 1441-1-2007 (air sound blocking performance of buildings and building members by the acoustic intensity method).

The result is shown in FIG.

The higher the value of the transmitted sound insertion loss, the better the sound insulation.

3. Consideration (1) As can be seen from FIG. 12 and Table 1, Examples 1 to 3 having the sound insulation layer 2, the sound absorbing layer 3 and the space layer 4 are referred to Comparative Examples 1, 3, 5 and 6 having no space layer 4. In comparison, it is excellent in sound absorption at a frequency of 1000 Hz in a low frequency region (corresponding to road noise with a frequency of 800 Hz or more and 1000 Hz or less).

On the other hand, Comparative Examples 4 and 7 did not have the spatial 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 had a thickness of 40 mm and 82 mm, which was unsuitable for miniaturization (thinning).

Further, the first embodiment including 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 second embodiment including the cylindrical column member 8. As described above, it is excellent in sound absorption at a frequency of 3500 Hz within (corresponding to an engine sound of 4000 Hz or less).

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

On the other hand, Comparative Example 7 did not have 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 has a thickness of 82 mm, which is unsuitable for miniaturization (thinning).

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

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

Claims (5)

With the sound absorbing layer,
A sound insulation layer arranged on one side in the thickness direction of the sound absorption layer,
A space layer that separates the sound absorbing layer and the sound insulating layer in the thickness direction is provided.
The sound insulation layer is a pressure-sensitive adhesive layer formed in layers from the pressure-sensitive adhesive composition.
Further provided with a closing portion for closing the peripheral end portion of the space layer,
A sound absorbing material, characterized in that the peripheral end portion of the sound absorbing layer becomes the closing portion by pressure-sensitive adhesion to the peripheral end portion of the sound insulating layer . Further provided with a plurality of column members extending in the thickness direction and arranged at intervals in the direction orthogonal to the thickness direction.
The sound absorbing material according to claim 1, wherein the plurality of pillar members are arranged between the sound absorbing layer and the sound insulating layer. A second sound insulation layer interposed between the pillar member and the sound absorption layer is further provided.
The sound absorbing material according to claim 2, wherein the second sound insulating layer has a surface density of 0.01 or more. The sound absorbing material according to claim 2 or 3, wherein each of the plurality of pillar members has an inclined surface that is inclined with respect to the thickness direction. The sound absorbing material according to claim 4, wherein each of the plurality of pillar members has a substantially conical shape in which the cross-sectional area increases toward one side in the thickness direction.

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