JP7160667B2 - soundproof material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a soundproofing material, and more particularly to a soundproofing material having a practically effective high-level sound absorption coefficient and a wide frequency range capable of absorbing sound.

In recent years, there has been a clear tendency for people to live in close quarters in small areas due to the progress of urbanization, the efficiency of administrative services, and the like. As the population density increases, activities such as living, working and recreational activities are carried out in close proximity, increasing the frequency and types of noise that people are exposed to. In order to secure a comfortable living environment even in a noisy environment, there is a demand for a soundproofing material that can generally block the daily life noise encountered in daily life. In addition, along with the miniaturization and weight reduction of various devices, which are the sound generators of everyday noise, there is a demand for thinner and lighter soundproofing materials used in these devices.

Life noise is emitted from, for example, transportation equipment, construction machinery/equipment, electronic/electric equipment, home appliances, etc. There are various kinds of noise, and includes sounds with a wide range of frequencies from low to high frequencies.

Taking the case of a car as an example, the sound range that penetrates into the room while driving is engine sound (about 63 to 250 Hz), tire sound (about 500 to 1500 Hz), and wind noise (about 1000 to 4000 Hz). ) have characteristics that show peaks in the mid-to-high range. In general, there are two soundproofing methods for automobiles: "sound insulation" to block sound entering from outside the vehicle and "sound absorption" to soften the reverberation of sound inside the vehicle. measures against intrusive sound are taken by means of sound absorption. Soundproofing materials are required to have better sound absorption performance than conventional products in order to reduce mid-to-high range sound, which is a characteristic of tire noise and wind noise, which is a concern that the problem will become more pronounced in next-generation vehicles.

As one of the soundproofing methods for blocking noise and abnormal sounds, there is the above-mentioned "sound absorption". Here, "sound absorption" refers to a method of suppressing sound reflection by absorbing sound, and the smaller the sound reflected by absorption, the higher the sound absorption. The mechanism of sound absorption is that when sound is incident on a material that is generally composed of the skeleton of a fiber material such as felt, glass wool, or rock wool and the gaps between them, part of the energy of the sound wave is absorbed in the gaps. Friction with the peripheral wall of the framework, viscous resistance, and vibration of the framework convert heat energy into heat energy, which absorbs sound. Sound consumes the most sound energy at the position where the particle velocity of the sound wave is high. Therefore, for example, if there is a soundproof material from the rigid wall to a position such as λ/4 where the particle velocity is high, the sound absorption rate will be high. Therefore, for example, the material attached to the rigid wall has a higher sound absorption coefficient at higher frequencies, and the thicker the soundproof material, the higher the sound absorption coefficient at low frequencies.

Patent Literature 1 describes an ultra-lightweight soundproof material that prevents the noise from the engine room of an automobile from propagating into the passenger compartment. This soundproofing material consists of a sound absorbing layer made of a breathable material such as thermoplastic felt, and a breathable resonance layer made of a lightweight foam or thin film, etc., with a predetermined bonding strength and bonding area by means of an adhesive layer. It consists of a laminate that is adhered so that it becomes.

The soundproofing material of Patent Document 1 utilizes an adhesive layer between the air-permeable resonance layer and the sound-absorbing layer to generate a resonance phenomenon at the interface between the air-permeable ultra-lightweight sound-absorbing layer and the sound-absorbing layer, thereby absorbing sound. The adhesion area and the density of the sound absorbing layer are used to adjust the spring-mass system resonance and rigidity, thereby controlling the frequency of the sound absorbed at the interface and the sound absorption rate. However, there is still room for improvement in the balance control of the sound absorption coefficient in the low to high frequency range (widening of the sound absorption characteristics) and thinning, and the frequency range that can absorb sound is not wide enough. .

Patent Literature 2 describes a sound absorbing material suitable for the interior of automobiles. This sound absorbing material is a nonwoven fabric joined with a surface material made of a thermoplastic synthetic fiber nonwoven fabric and a back material made of a synthetic fiber nonwoven fabric by a spunbond method, which is partially thermocompressed and further calendered.

The sound absorbing material of Patent Document 2 has an average fiber diameter of 10 to 30 μm in the surface material and a thick back surface material, thereby having a high sound absorption coefficient in a medium frequency range (2000 to 4000 Hz). However, when the total thickness of this soundproof material is reduced, the sound absorption coefficient tends to decrease, especially at 2000 Hz. In other words, the sound absorbing material of Patent Document 2 still has room for improvement in terms of the sound absorption coefficient in the frequency range of 2000 Hz or less if the thickness is made thinner in order to meet the growing demand for thinner and lighter weight materials in the future. , the sound absorbing frequency range is not wide enough. Moreover, even if the backing material is thickened, there is a possibility that the sound absorption coefficient in the frequency range of 2000 Hz or less cannot be sufficiently increased.

Patent Document 3 discloses two sound absorbing layers that absorb noise by a porous sound absorbing function, and a resonance integrated between the two sound absorbing layers to absorb noise propagating from the sound absorbing layers by a resonance action. A vehicle acoustic insulation is described comprising a layer.

The soundproofing material of Patent Document 3 has a thin resonance layer and a small bending load, so that the resonance layer itself vibrates easily, and by enhancing the membrane vibration sound absorption function, noise in the low and medium frequency ranges can be effectively suppressed. sound absorption treatment. Furthermore, by laminating a low-permeability skin layer on the surface of the second sound-absorbing layer, it is possible to improve the sound-absorbing characteristics of noise in the middle and high frequency ranges. However, this soundproof material still has room for improvement in the balance control of the sound absorption coefficient in the low to high frequency range (broadening of the sound absorption characteristics), and it cannot be said that the sound absorbing frequency range is sufficiently wide.

JP 2005-208494 A Japanese Unexamined Patent Application Publication No. 2006-28709 JP 2009-90845 A

The present invention is intended to solve the above-mentioned conventional problems, and its purpose is to have a practically effective high level of sound absorption coefficient while maintaining thinness, and to expand the frequency range in which sound can be absorbed. To provide a soundproofing material that is

In order to solve the above problems, the present inventors have made intensive studies and found that a porous material in which voids are communicated on both sides of an intermediate layer made of a fibrous material having a structure having a specific average fiber diameter and air permeability. is partially bonded with a bonding layer made of a bonding material so as to achieve a predetermined bonding area ratio, and the surface of the sound absorbing layer on the sound source side has a specific average fiber diameter and air permeability. A laminate made by partially bonding the skin layer made of the fiber material of the above so that the bonding layer made of the bonding material has a predetermined bonding area ratio, even if the total thickness of the laminate is reduced In addition, the present inventors have found that it has an effectively high level of sound absorption coefficient and is effective as a soundproofing material with an expanded frequency band capable of absorbing sound, and have completed the present invention.

The present invention has a first sound absorbing layer, a first bonding layer, an intermediate layer, a second bonding layer, a second sound absorbing layer, a third bonding layer, and a skin layer laminated in order, and The first sound absorbing layer and the second sound absorbing layer are each independently made of a porous material with interconnecting voids, and the intermediate layer has an average fiber diameter of 1 to 17 μm and a fiber size of ⁵ to 200 cm cm ² ·sec, the skin layer is made of a fibrous material having an average fiber diameter of 1 to 10 μm and an air permeability of 5 to 200 cm ³ /cm ² ·sec, and the first S1 is the bonding area ratio to the entire contact surface between the first sound absorbing layer and the intermediate layer in the bonding layer, and the bonding area to the entire contact surface between the second sound absorbing layer and the intermediate layer in the second bonding layer S2 is the ratio, and S3 is the bonding area ratio to the entire contact surface between the skin layer and the second sound absorbing layer in the third bonding layer, any one of S1, S2, and S3 The joint area ratio is in the range of 52-95%, and the remaining two joint area ratios are in the range of 3-97% to provide a sound insulation material.

In one aspect, the bonding area ratio of any one of S1, S2, and S3 is in the range of 80 to 95%, and the bonding area ratio of the remaining two is in the range of 3 to 97%. be.

In one aspect, any two of the S1, S2, and S3 have a bonding area ratio in the range of 80 to 95%, and the remaining one has a bonding area ratio in the range of 3 to 97%. be.

In one embodiment, the bonding material is a coated adhesive or double-sided adhesive tape.

In one embodiment, the applied pressure-sensitive adhesive or the pressure-sensitive adhesive of the double-sided pressure-sensitive adhesive tape has a shear storage elastic modulus at 25° C. of 1.0×10 ⁴ to 1.0×10 ⁶ Pa.

In one aspect, the first bonding layer, the second bonding layer, and the third bonding layer are formed from a plurality of rod-shaped layers.

In one certain form, the plurality of rod-shaped layers form a striped pattern.

In one certain form, the space|interval of adjacent rod-shaped layers is 1 mm or more.

In one embodiment, at least one selected from the group consisting of the intermediate layer and the skin layer has an air permeability of 10 to 100 cm ³ /cm ² ·sec.

In one aspect, the first sound absorbing layer and the second sound absorbing layer are fibrous materials, and the basis weight of the fibrous materials is 100 to 300 g/m ² .

In one aspect, the total thickness of the soundproof material is 10 to 30 mm.

In one embodiment, the soundproof material has a normal incident sound absorption coefficient measured in accordance with JIS A1405-2 of 55 at all center frequencies of 1250, 1600, 2000, 2500, 3150 and 4000 Hz in the 1/3 octave band. % or more.

In one embodiment, the soundproof material has a normal incident sound absorption coefficient measured in accordance with JIS A1405-2 at center frequencies of 1000, 1250, 1600, 2000, 2500, 3150, and 4000 Hz in the 1/3 octave band. It is 55% or more in all.

Since the soundproof material of the present invention is thin and excellent in practicality, and has an expanded frequency range in which sound can be absorbed, it is possible to effectively absorb various kinds of noise in everyday life.

FIG. 1 is a perspective view schematically showing the configuration of a soundproof material that is one embodiment of the present invention. FIG. 2 is a horizontal cross-sectional view schematically showing an example of the structure of the bonding layer of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Composition of soundproofing material]
FIG. 1 is a perspective view schematically showing the configuration of a soundproof material that is one embodiment of the present invention. The soundproofing material 10 includes an intermediate layer 13 made of a fibrous material, a first sound absorbing layer 11 made of a porous material in which voids are communicated and laminated on one side of the intermediate layer 13, and the intermediate layer 13. A second sound absorbing layer 15 made of a porous material with communicating voids and laminated on the other surface of the above, a skin layer 17 laminated on the sound source side surface of the second sound absorbing layer, and the above A first bonding layer 12 made of a bonding material, which is laminated between the intermediate layer 13 and the first sound absorbing layer, and a second bonding layer which is laminated between the intermediate layer and the second sound absorbing layer. It has a laminated structure including a bonding layer 14 and a third bonding layer 16 made of a bonding material and laminated between the skin layer 17 and the second sound absorbing layer. Further, the soundproof material 10 has an opening 18 without a bonding material between the intermediate layer 13 and the first sound absorbing layer 11, and an opening 18 between the intermediate layer 13 and the second sound absorbing layer 15. There is an opening 19 without bonding material and an opening 20 without bonding material between the skin layer 17 and the second sound absorbing layer 15 . The soundproof material 10 is used, for example, as a member for absorbing sound emitted from sounding bodies such as transportation equipment, construction machinery/equipment, electronic/electric equipment, and household appliances.

<Joining layer>
The first bonding layer 12, the second bonding layer 14, and the third bonding layer 16 include the intermediate layer 13 and the first sound absorbing layer 11, the intermediate layer 13 and the second sound absorbing layer 15, and the skin layer, respectively. 17 and the second sound absorbing layer 15, the intermediate layer 13 and the first sound absorbing layer 11, the intermediate layer 13 and the second sound absorbing layer 15, and the skin layer 17 and the second sound absorbing layer A bonding material is used on the contact surfaces that come into contact when 15 is laminated, and the bonding area ratio is formed so as to fall within the range of a predetermined bonding area ratio described later. As the bonding material, a material that can be easily and accurately realized in shape and size and has substantially no communicating voids is used.

As the bonding material, for example, a material containing a pressure-sensitive adhesive, an adhesive, or the like can be used. Specifically, a coated pressure-sensitive adhesive, a coated adhesive, or a tape-shaped, sheet-shaped, or powder-shaped material obtained by processing these may be used. Among them, from the viewpoint of workability, productivity, and dimensional accuracy, the first bonding layer 12, the second bonding layer 14, and the third bonding layer 12, the second bonding layer 14 and the third It is preferable to form the bonding layer 16 of

The coated pressure-sensitive adhesive or the pressure-sensitive adhesive used in the double-sided pressure-sensitive adhesive tape is not particularly limited, and conventionally known pressure-sensitive adhesives can be used. Examples thereof include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, polyester-based adhesives, and ethylene-vinyl acetate copolymer-based adhesives. Among these, rubber-based adhesives or acrylic-based adhesives are preferable from the viewpoints of versatility, a wide range of variable thickness, and not excessively restricting the surface layer, the sound absorbing layer, and the intermediate layer. The shear storage modulus (G') of the pressure-sensitive adhesive at 25° C. is preferably in the range of 1.0×10 ⁴ to 1.0×10 ⁶ Pa. By setting the shear storage elastic modulus in such a range, the skin layer 17, the second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11 can be deformed or displaced by sound vibration to some extent. , the surface layer 17, the second sound absorbing layer 15, the intermediate layer 13, the first sound absorbing layer 11, and the soundproof material can pass sound waves to some extent without causing a hard portion that reflects sound in the boundary layer. The sound absorbing mechanism of 10 as a whole can be made to function without problems. The shear storage modulus (G') of the pressure-sensitive adhesive at 25° C. is preferably in the range of 5.0×10 ⁴ to 8.0×10 ⁵ Pa, more preferably 1.0×10 ⁵ to 6.0×10 5 Pa. It is in the range of 0×10 ⁵ Pa.

The first bonding layer 12, the second bonding layer 14, and the third bonding layer 16 are connected to the intermediate layer 13 and the first sound absorbing layer 11, and the intermediate layer 13 and the second sound absorbing layer 15, respectively, as described above. , and a function for joining and fixing the skin layer 17 and the second sound absorbing layer, where the inventors have found an intermediate layer made of a fibrous material with a structure having a specific average fiber diameter and air permeability. A layer 13, a first sound absorbing layer 11 and a second sound absorbing layer 15 made of a porous material with communicating voids, and a skin layer 17 made of a fiber material having a specific average fiber diameter and air permeability. When used, the bonding area ratio of the entire contact surface between the intermediate layer 13 and the first sound absorbing layer 11 in the first bonding layer 12 is S1, and the intermediate layer 13 in the second bonding layer 14 and the second When the bonding area ratio of the entire contact surface with the sound absorbing layer 15 is S2, and the bonding area ratio of the entire contact surface between the skin layer 17 and the second sound absorbing layer 15 in the third bonding layer 16 is S3, the above S1 , S2, and S3, the bonding area ratio of one of them is in the range of 52 to 95%, and the remaining two bonding area ratios are in the range of 3 to 97%. Even if the thickness of the soundproofing material is thinner than that of the soundproofing material, the frequency at which the normal incidence sound absorption coefficient is maximized (sound absorption peak frequency) can be shifted toward lower frequencies. It was found that the normal incidence sound absorption coefficient does not decrease significantly and maintains a relatively large value even in the low frequency band and the high frequency band with respect to the peak frequency. In other words, the present inventors have found that there is an effect of further expanding the frequency band capable of absorbing sound in actual use.

Although the details of the mechanism that produces the above effect are not clear, it is speculated as follows. First, as for the sound absorption characteristics of the first sound absorption layer 11 alone, which is made of a porous material with communicating voids serving as a base, the sound absorption coefficient increases as the frequency increases, and reaches a substantially constant value at a certain frequency. The rate is generally not high. In order to increase the overall sound absorption coefficient of a soundproof material made of a porous material with interconnecting voids, generally, the thickness of the sound absorbing layer alone of the first sound absorbing layer 11 is increased, or another It is effective to increase the total thickness of a laminate in which the second sound absorbing layer 15 is simply superimposed on the first sound absorbing layer 11. It is difficult to sufficiently increase the sound absorption coefficient in the middle frequency band, and it is not suitable for thinning and lightening. On the other hand, the intermediate layer 13 made of a fibrous material having a structure having an average fiber diameter of 1 to 17 μm and an air permeability of 5 to 200 cm ³ /cm ² ·sec, and an average fiber diameter of 1 to 10 μm and an average fiber diameter of 5 to 200 cm ³ /cm ² .・Since the skin layer 17 made of a fibrous material having an air permeability of sec has a relatively dense structure, it is presumed that it has a sound absorption characteristic that combines a resonance type sound absorption mechanism and a porous type sound absorption mechanism. The contact area and flow resistance between the and the vibrating air (sound waves) tend to be relatively large, and have the effect of increasing the sound absorption coefficient in the medium to high frequency range. Therefore, for example, if a laminate is formed by simply stacking the skin layer 17, the second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11 in this order from the sound wave incident side without bonding with a bonding layer, the 1 sound absorbing layer 11 alone, or a layered body in which the first sound absorbing layer 11 and the second sound absorbing layer 15 are simply superimposed, the sound absorption coefficient in the medium to high frequency range increases and decreases. There is also a concomitant increase in the sound absorption coefficient in the ~mid-frequency range. However, the sound absorption coefficient in the frequency band below 1250 Hz is still low. Therefore, in order to increase the sound absorption coefficient in the frequency band of 1250 Hz or less, each layer of the skin layer 17, the second sound absorption layer 15, the intermediate layer 13, and the first sound absorption layer 11 is bonded with a third bonding agent such as an adhesive. The entire surface is bonded by the layer 16, the second bonding layer 14, and the first bonding layer 12 (bonded area ratio = 100%), and the sound absorption peak frequency is reduced in the low frequency direction by using the membrane vibration type sound absorption mechanism at each bonding interface. , the sound absorption peak frequency certainly shifts toward lower frequencies, and the sound absorption coefficient near the sound absorption peak frequency also increases, but this time, the sound absorption coefficient in the high frequency band decreases.

In the present invention, the skin layer 17 and the second sound absorbing layer 15 are connected by the third bonding layer 16, the second sound absorbing layer 15 and the intermediate layer 13 are connected by the second bonding layer 14, and the first The bonding layer 12 does not bond the intermediate layer 13 and the first sound absorbing layer 11 over the entire surface, but the entire contact surface between the skin layer 17 and the second sound absorbing layer 15 in the third bonding layer 16 The bonding area ratio is S3, the bonding area ratio of the entire contact surface between the second sound absorbing layer 15 and the intermediate layer 13 in the second bonding layer 14 is S2, the intermediate layer 13 and the first bonding layer 13 in the first bonding layer 12 are S2. When the bonding area ratio of the entire contact surface with the sound absorbing layer 11 is S1, any one of the bonding area ratios S3, S2, and S1 is in the range of 52 to 95%, and the remaining two The openings 20 so that the two bonding area ratios are in the range of 3 to 97%, in other words, the third bonding layer 16 has an opening ratio in a predetermined range (= 100% - bonding area ratio S3), The second bonding layer 14 has openings 19 that have a predetermined range of opening ratio (=100%−bonding area ratio S2), and the first bonding layer 12 has a predetermined range of opening ratio (=100%−bonding). (1) Sound waves transmitted through the surface layer 17 without being absorbed by the surface layer 17 can enter the second sound absorbing layer 15, and (2) Sound waves transmitted without being absorbed by the skin layer 17 and the second sound absorbing layer 15 can enter the intermediate layer 13, and (3) the skin layer 17, the second sound absorbing layer 15, And the sound waves transmitted through the intermediate layer 13 without being absorbed can penetrate into the first sound absorbing layer 11, and thus penetrate into the framework of the second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11. It is possible to transmit and vibrate the sound waves, thereby efficiently converting sound energy into heat energy. As a result, the lowered sound absorption coefficient in the high frequency band can be increased compared to the case where the whole surface is joined. At this time, particularly when the third bonding layer 16, the second bonding layer 14, and the first bonding layer 12 are adhesives having viscoelasticity, the skin layer 17 and the second sound absorbing layer 15 Since the intermediate layer 13 and the first sound absorbing layer 11 are not excessively constrained, the skin layer 17, the second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11 are deformed or displaced by sound vibration to some extent. The second sound absorbing layer 15, the intermediate layer 13, the first sound absorbing layer 11, and the soundproofing material 10 as a whole can pass sound waves to some extent without creating a hard portion that reflects sound in the boundary layer. It is possible to function the sound absorbing mechanism as a function without any problem.

Furthermore, by providing such openings 18 , 19 , and 20 , the contact bonding layer 12 , the first sound absorbing layer 11 , the laminated structure portion having the openings 18 , the bonding layer 14 , and the intermediate layer 13 and the openings 19, and the laminate structure portion having the bonding layer 16, the second sound absorbing layer 15, and the openings 20, any one of the laminate structure portions includes (1) the air-permeable openings 18 The porous material (first or (2) the total aperture ratio of the air-permeable openings 19 (opening ratio = 100% - joint area ratio S2) is 5 Helmholtz resonator type sound absorption with a relatively densely structured fiber material (intermediate layer 13) bonded directly to the back of a perforated viscoelastic membrane (bonding layer 14) of ~48% instead of an air layer (3) a perforated viscoelastic film (bonding layer 16) having a total opening ratio (opening ratio = 100% - bonding area ratio S2) of the air-permeable openings 20 of 5 to 48%; Since it can be regarded as a type of sound absorbing layer having a Helmholtz resonator type sound absorbing mechanism having a porous material (second sound absorbing layer 15) with interconnecting voids on the back surface, the sound absorption peak frequency is set on the low frequency side. It is possible to maintain the ability to shift to a certain extent. Note that increasing the bonding area ratios of the first bonding layer 12, the second bonding layer 14, and the third bonding layer 16 increases the surface density of each bonding layer, It means that the aperture ratio of is decreased, and it is considered that the peak sound absorption frequency shifts toward lower frequencies based on the membrane vibration type mechanism and the resonator type sound absorption mechanism as the areal density increases. Therefore, when the bonding area ratio S1 of the first bonding layer 12, the bonding area ratio S2 of the second bonding layer, and the bonding area ratio S3 of the third bonding layer are all less than 52%, the surface density It is considered that the effect of the increase is insufficient, and the sound absorption coefficient in the frequency band of 1250 Hz or less does not sufficiently increase in the soundproof material 10 . Therefore, in order to expand the frequency band that can be absorbed while maintaining the balance of the sound absorption coefficient, any one of the joint area ratios S1, S2, and S3 should be set to 52 to 95% as described above. , it is important to set the bonding area ratios of the remaining two in the range of 3 to 97%.

As a result, the soundproof material 10 of the present invention couples the resonance at the bonding interface with the fiber vibration in the skin layer, the sound absorbing layer, and the intermediate layer, and furthermore, the openings of the bonding layer reduce the viscous resistance of the sound absorbing layer and the intermediate layer. Therefore, each sound absorption mechanism is synergistically expressed in a well-balanced manner, and even if the total thickness of the soundproof material 10 is thin, it has a high level of sound absorption coefficient effective in actual use, and is capable of sound absorption. It is inferred that this has the effect of expanding the frequency band.

In the soundproof material 10 of the present invention, among the bonding area ratio S1 of the first bonding layer 12, the bonding area ratio S2 of the second bonding layer 14, and the bonding area ratio S3 of the third bonding layer 16, Any one bonding area ratio is in the range of 52 to 95%, preferably 80 to 95%, and the remaining two bonding area ratios are in the range of 3 to 97%.

That is, (1) when the bonding area ratio S1 is in the range of 52 to 95%, the remaining two bonding area ratios S2 and S3 are in the range of 3 to 97%. Also, the bonding area ratio S1 is preferably in the range of 80 to 95%. Here, if the joint area ratio S1 is less than 52%, and the joint area ratio S2 and the joint area ratio S3 are small, the sound absorption coefficient of the soundproof material in the frequency band of 1250 Hz or less may decrease. When S1 exceeds 95%, the sound absorption coefficient of the soundproof material in the frequency band of 3150 to 4000 Hz may decrease when the joint area ratio S2 and the joint area ratio S3 are large. Further, if the joint area ratio S2 and the joint area ratio S3 are less than 3%, the sound absorption coefficient of the soundproof material in the frequency band of 1250 Hz or less may decrease when the joint area ratio S1 is small. exceeds 97%, the sound absorption coefficient of the soundproof material in the frequency band of 3150 to 4000 Hz may decrease when the joint area ratio S1 is large.

(2) When the bonding area ratio S2 is in the range of 52 to 95%, the remaining two bonding area ratios S1 and S3 are in the range of 3 to 97%. Also, the bonding area ratio S2 is preferably in the range of 80 to 95%. Here, if the joint area ratio S2 is less than 52%, and the joint area ratio S1 and the joint area ratio S3 are small, the sound absorption coefficient of the soundproof material in the frequency band of 1250 Hz or less may decrease. When S2 exceeds 95%, the sound absorption coefficient of the soundproof material in the frequency band of 3150 to 4000 Hz may decrease when the joint area ratio S1 and the joint area ratio S3 are large. Further, if the joint area ratio S1 and the joint area ratio S3 are less than 3%, the sound absorption coefficient of the soundproof material in the frequency band below 1250 Hz may decrease when the joint area ratio S2 is small. And when the joint area ratio S3 exceeds 97%, the sound absorption coefficient of the soundproof material in the frequency band of 3150 to 4000 Hz may decrease when the joint area ratio S2 is large.

Further, (3) when the bonding area ratio S3 is in the range of 52 to 95%, the remaining two bonding area ratios S1 and S2 are in the range of 3 to 97%. Also, the bonding area ratio S3 is preferably in the range of 80 to 95%. Here, when the joint area ratio S3 is less than 52%, when the joint area ratio S1 and the joint area ratio S2 are small, the sound absorption coefficient of the soundproof material in the frequency band of 1250 Hz or less may decrease. When S3 exceeds 95%, the sound absorption coefficient of the soundproof material in the frequency band of 3150 to 4000 Hz may decrease when the joint area ratio S1 and the joint area ratio S2 are large. Further, if the joint area ratio S1 and the joint area ratio S2 are less than 3%, the sound absorption coefficient of the soundproof material in the frequency band of 1250 Hz or less may decrease when the joint area ratio S3 is small. And when the joint area ratio S2 exceeds 97%, the sound absorption coefficient of the soundproof material in the frequency band of 3150 to 4000 Hz may decrease when the joint area ratio S3 is large.

The shapes of the first bonding layer 12, the second bonding layer 14, and the third bonding layer 16 are the bonding area ratio S1 of the first bonding layer 12, the bonding area ratio S2 of the second bonding layer 14, and the bonding area ratio S3 of the third bonding layer 16, any one bonding area ratio between the first sound absorbing layer 11 and the intermediate layer 13, the intermediate layer 13 and the second sound absorbing layer 15, and the second 52 to 95% of the entire contact surface between the sound absorbing layer 15 and the skin layer 17, and the remaining two joint area ratios are in the range of 3 to 97%, that is, the air permeable openings 18, opening 19, and opening 20, the total opening ratio of any one opening is in the range of 5 to 48%, and the total opening ratio of each of the remaining two openings is in the range of 3 to 97%. There is no particular limitation as long as the air-permeable openings 18, 19, and 20 are formed in a part of the contact surface so as to fall within the range. For example, shapes such as a linear shape, a dot shape, and a punching sheet shape (a shape in which holes are made in a sheet) can be mentioned. Preferably, a plurality of air-permeable openings 18, 19, and 20 are formed over the entire contact surface.

FIG. 2 is a horizontal sectional view schematically showing an example of the structure of the first bonding layer 12 of the invention. From the viewpoint of workability and workability, in a preferred embodiment, the first bonding layer 12, the second bonding layer 14 (not shown), and the third bonding layer 16 (not shown) are , for example, a plurality of bar-shaped layers. A bar-shaped layer refers to a linear layer having a predetermined width. When the rod-shaped bonding layers are formed in a uniform pattern over the entire contact surface, the plurality of rod-shaped layers form a striped pattern. A striped pattern is a linear pattern in which straight lines are arranged in parallel at regular intervals. As a result, the air-permeable openings 18, 19 (not shown) and 20 (not shown) are formed between two adjacent bar-shaped layers on the contact surface. be.

The width of the rod-shaped layer is appropriately determined in consideration of the bonding area ratio, the desired sound absorption property, the size of the soundproofing material to be used, the number of rod-shaped layers, etc., but is preferably 1 mm or more. If the width of the rod-shaped layer is less than 1 mm, it may be difficult to maintain and process the shape and dimensions accurately. On the other hand, the upper limit of the width of the rod-shaped layer is not particularly limited as long as it does not interfere with the effects of the present invention. It is preferable to have at least a plurality of openings 18, 19, and 20, and preferably 26.4 mm or less, for example. Moreover, the width of each of the plurality of rod-shaped layers may be the same or different.

The interval between the adjacent rod-shaped layers is appropriately determined in consideration of the bonding area ratio, the sound absorption characteristics, the size of the soundproofing material to be used, the number of rod-shaped layers, etc., but is preferably 1 mm or more. . If the distance between adjacent rod-shaped layers is less than 1 mm, it may be difficult to maintain and process the shape and dimensions accurately, and adjacent rod-shaped layers may come into contact with each other, preventing the formation of openings. . On the other hand, the upper limit of the interval between the adjacent rod-shaped layers is not particularly limited as long as it does not interfere with the effects of the present invention. 8 mm), it is preferable to set at least a plurality of openings 18, 19, and 20, for example, 26.4 mm or less. Further, the intervals between the plurality of rod-shaped layers may be the same or different.

The thicknesses of the first bonding layer 12, the second bonding layer 14, and the third bonding layer 16 are not particularly limited as long as the effects of the present invention are not hindered. A range of ~3 mm is preferred. If the thickness of the bonding layer is less than 0.025 mm, the sound absorption coefficient of the soundproof material 10 may decrease as a whole, the bonding strength between the intermediate layer 13 and the first sound absorbing layer 11, There is a possibility that the bonding strength between the second sound absorbing layer 15 and the skin layer 17 and the second sound absorbing layer 15 may be lowered. On the other hand, if the thickness of the bonding layer exceeds 3 mm, the sound absorption coefficient of the soundproofing material 10 in the high frequency band may decrease if the bonding area is large, and the thickness and weight of the soundproofing material 10 increase. Not suitable for thin and light weight. Further, the densities of the first bonding layer 12, the second bonding layer 14, and the third bonding layer 16 are not particularly limited as long as the effects of the present invention are not hindered. from the point of view, it is preferably in the range of 1.0 to 1.5 g/cm ³ .

In general, soundproofing materials made of only porous materials such as felt and glass wool have a sound absorption coefficient that increases as the frequency increases and reaches an almost constant value at a certain frequency. Along with increasing the sound absorption coefficient of the frequency band of 4000 Hz (middle to high frequency band), the sound absorption coefficient of the frequency band of 2000 Hz or less (middle to low frequency band) is increased to a certain level, making it an effective frequency as a sound absorbing material. Bandwidth can be expanded. That is, the effective sound absorption frequency band is controlled by controlling the thickness of the soundproof material. However, in such a control method, if the space for installing the soundproofing material is limited or if it is desired to make the soundproofing material thinner or lighter, the desired design (for example, thinness and weight reduction and effective sound absorption frequency There arises a problem that it is not possible to satisfactorily satisfy the requirement (coexistence with expansion of the band). As described above, the soundproofing material 10 of the present invention uses a bonding layer that joins the base material of the skeleton without increasing or changing the total thickness of the soundproofing material 10, and uses the first Any one of the bonding area ratio S1 of the bonding layer 12, the bonding area ratio S2 of the second bonding layer 14, and the bonding area ratio S3 of the third bonding layer 16 is set to 52 to 95%. By controlling the range and the remaining two joint area ratios in the range of 3 to 97%, it is possible to expand the effective sound absorption frequency band as a soundproof material, so to provide an effective solution to the above problems. can be done. Further, by using a specific intermediate layer 13 and a skin layer 17, which will be described later, even when the total thickness of the soundproof material 10 is made thinner than that of the conventional product, it has a practically effective high level sound absorption coefficient. , the sound absorption frequency band effective as a soundproof material can be widened.

<Middle layer>
The fiber material of the intermediate layer 13 has an average fiber diameter in the range of 1 to 17 μm and an air permeability in the range of 5 to 200 cm ³ /cm ² ·sec. A fibrous material is a material whose shape is supported by fibers and which has spaces between the fibers through which gas can pass. The fibrous material is preferably sheet-like. Non-woven fabrics, woven fabrics and knitted fabrics are included in the fibrous materials referred to herein. On the contrary, a resin foam or a resin film material is not included in the fibrous material referred to here even if it is a material having air permeability.

By setting the average fiber diameter and air permeation amount of the intermediate layer 13 within the above ranges, the fiber material of the intermediate layer 13 tends to have a relatively dense structure, and both the resonance type sound absorbing mechanism and the porous type sound absorbing mechanism can be obtained. , that is, the effect of increasing the sound absorption coefficient in the middle to high frequency range. At the same time, the sound absorption coefficient in the frequency band of 2000 Hz or less (middle to low frequency band) can also be raised to a certain level incidentally. Therefore, as described above, when the intermediate layer 13 is bonded between the first sound absorbing layer 11 and the second sound absorbing layer 15 via the first bonding layer 12 and the second bonding layer 14, , the lamination portion of the first bonding layer 12 and the intermediate layer 13, and the lamination portion of the second bonding layer 14 and the intermediate layer 13, the sound absorption coefficient in the high frequency band tends to decrease as the bonding area ratio increases. However, since the viscous resistance of the intermediate layer can be utilized by having openings with a predetermined open area ratio, this phenomenon can be covered by the characteristics of the intermediate layer 13 as well. The soundproof material 10 of the invention can produce an effect of expanding the frequency band capable of absorbing sound in actual use even if the thickness is thin.

In the present embodiment, the fibrous material of the intermediate layer 13 is not particularly limited, but it is preferable to use a nonwoven fabric made of synthetic fibers. Examples of fibers constituting the nonwoven fabric include polyolefin fibers such as polyethylene, polypropylene and copolymerized polypropylene; polyamide fibers such as nylon 6, nylon 66 and copolymerized polyamide; polyethylene terephthalate, polybutylene terephthalate, copolymerized polyester; Polyester fiber such as aliphatic polyester, acrylic fiber, aramid fiber, composite fiber such as core-sheath structure with polyethylene, polypropylene or copolyester sheath and polypropylene or polyester core, polylactic acid, polybutylene sax Thermoplastic synthetic fibers such as biodegradable fibers such as polystyrene succinate and polyethylene succinate can be used. These fibers can be used singly or in combination of two or more. In addition, modified cross-section fibers such as flat yarns, crimped fibers, split fibers, etc. can be used in combination or in layers. Among these, polyester fibers are particularly preferred from the viewpoint of versatility, heat resistance, flame retardancy, and the like.

The average fiber diameter of the fibers constituting the fibrous material of the intermediate layer 13 is in the range of 1-17 μm, preferably in the range of 2-10 μm. The diameter of the fibers constituting the intermediate layer 13 has a structure with small voids to increase the sound absorption coefficient in the medium to high frequency band, and at the same time, to increase the sound absorption coefficient in the frequency band of 2000 Hz or less (middle and low frequency band) as much as possible. In addition, it is preferable to make it small. The fiber diameters of the fibers constituting the fiber material may be the same or different. When the fiber diameters are different, the fiber material is a mixture of thick fibers with an average fiber diameter of 17 μm or more and thin fibers with an average fiber diameter of less than 17 μm, so that the average fiber diameter is in the range of 1 to 17 μm. I don't mind if you donate. If the average fiber diameter of the fibers constituting the fibrous material is less than 1 μm, the strength, rigidity, handleability, etc. may deteriorate, and the price may be disadvantageous. On the other hand, if the average fiber diameter exceeds 17 μm, the sound absorption coefficient in the middle to high frequency range of the soundproof material may decrease, and the sound absorption coefficient in the frequency range of 2000 Hz or less (middle to low frequency range) may also decrease.

The air permeability of the fibrous material of the intermediate layer 13 is in the range of 5 to 200 cm ³ /cm ² ·sec, preferably in the range of 10 to 100 cm ³ /cm ² ·sec, more preferably 20 to 80 cm ³ /sec. It is in the range of cm ² ·sec. If the ventilation rate of the intermediate layer 13 is less than 5 cm ³ /cm ² ·sec, the sound absorption coefficient of the soundproof material in the middle to high frequency range may decrease. On the other hand, if the ventilation rate of the intermediate layer 13 exceeds 200 cm ³ /cm ² ·sec, the sound absorption coefficient of the soundproof material in a frequency band of 2000 Hz or less (middle to low frequency band) may decrease.

The thickness of the intermediate layer 13 is preferably in the range of 0.01 to 5 mm, more preferably in the range of 0.05 to 4 mm. The basis weight of the intermediate layer 13 is preferably in the range of 5-300 g/m ² , more preferably in the range of 15-100 g/m ² . Furthermore, the average apparent density of the intermediate layer 13 is preferably in the range of 0.01 to 1.0 g/cm ³ and more preferably in the range of 0.02 to 1.0 g/m ³ .

By setting the thickness, average apparent density, and weight per unit area of the intermediate layer 13 as described above, the sound energy of the sound waves that pass through the fiber material is transferred to the air friction in the vicinity of the inlet of the void and the inner wall of the fiber skeleton. It can be consumed more effectively by viscous friction and the like. When the intermediate layer 13 has a thickness of less than 0.01, an average apparent density of less than 0.01 g/cm ³ , and a basis weight of less than 5 g/m ² , the strength, rigidity, fiber density, and the like decrease, resulting in poor handleability. And the sound absorption effect may decrease. On the other hand, when the thickness of the intermediate layer 13 exceeds 5 mm, the average apparent density exceeds 1.0 g/m ³ , and the basis weight exceeds 300 g/m ² , strength and fiber density increase, but rigidity decreases. If it is too large, there is a possibility that the cuttability and handleability may deteriorate. In addition, it is not suitable for thinning and lightening.

The method for producing the fibrous material of the intermediate layer 13 is not particularly limited, and conventionally known wet methods, dry methods, and methods for producing nonwoven fabrics by direct spinning (spunbond, melt blow, etc.) can be mentioned. Among these, from the viewpoint of strength, handleability, and pore uniformity of the fibrous material, for example, nonwoven fabrics in which the warp and weft yarns are arranged almost perpendicularly or nonwoven fabrics in which the warp yarns are arranged only in one direction or a method for producing a non-woven fabric in which thick fibers and thin fibers are inter-fiber-bonded by a binder, but these are only examples and are not limited to these.

The above-mentioned weft-crossed nonwoven fabric is produced by first stretching fibers directly spun from the above-described raw material resin such as polyester, and then processing and preparing two types of webs in which the fibers are arranged in the vertical and horizontal directions. The web is laminated so that the fibers arranged in the web are perpendicular to each other and joined by point heat fusion by heat embossing. In addition to heat embossing, other methods for laminating vertical and horizontal webs include a method of impregnating and adhering with an emulsion, and a method of entangling short fibers with a water jet to combine and integrate them. Similarly, it is possible to manufacture a nonwoven fabric in which fibers are arranged only in the longitudinal direction, and this nonwoven fabric may be used as a fibrous material. The nonwoven fabric produced by such a method differs from the nonwoven fabric produced by the conventional spunbond method in that ultrafine fibers with an average fiber diameter of several μm are arranged in the vertical and horizontal directions or in the longitudinal direction. Therefore, deformation when a load is applied is small and the shape can be maintained, so secondary processing (roll-to-roll processing) that requires tension can be easily performed even with a low basis weight. The tensile strength (according to ASTM D882) of these nonwoven fabrics is preferably in the range of 20 to 300 N/50 mm in the MD direction.

The non-woven fabric in which the thick fibers and thin fibers are inter-fiber-bonded by a binder is obtained by first cutting fibers having different fiber diameters, which are melt-spun or wet-spun from the above-described raw material resin such as polyester, into flocks having a fiber length of 10 mm or less, for example. , mixed with fibers such as polyvinyl alcohol as a binder to prepare a uniformly dispersed suspension, and then manufactured by a normal papermaking method. The fibers having different fiber diameters may be made of the same material or may be made of different materials. At the time of sheeting, in addition to the papermaking method which is a wet method, a dry method in which short fibers are sheeted by a webber (air laid method) using a carding machine and an air flow may be used. The fiber arrangement may be either cross or random.

<Sound absorbing layer>
The first sound absorbing layer 11 and the second sound absorbing layer 15 are made of a porous material with interconnecting voids. The porous material with communicating voids is not limited as long as it can be used as a sound absorbing material, but felt, nonwoven fabric made of synthetic fibers (needle-punched synthetic fiber mixture or synthetic fiber 100 % felt) and foam materials having open cells.

Examples of the above-mentioned fiber materials include felts made from cotton, wool, wood wool, waste fibers, etc., processed with thermosetting resin (general name: resin felt); polyester fiber felt such as polyethylene terephthalate, nylon fiber, etc. Felt, polyethylene fiber felt, polypropylene fiber felt, acrylic fiber felt, composite fiber felt having a core-sheath structure with a sheath made of polyethylene, polypropylene or copolyester and a core made of polypropylene or polyester, polylactic acid, poly Synthetic fiber felts such as biodegradable fiber felts such as butylene succinate and polyethylene succinate; and inorganic fiber felts such as silica-alumina ceramics fiber felt, silica fiber felt, glass wool, rock wool and rock wool long fibers. Examples of foam materials having open cells include rubbers such as polyurethane foam, polyethylene foam, polypropylene foam, phenol foam, melamine foam; nitrile-butadiene rubber, chloroprene rubber, styrene rubber, silicone rubber, urethane rubber, and EPDM. Examples include those foamed in the form of open cells, and those subjected to crushing processing or the like after foaming to open holes in the foam cells to form open cells. Among these, synthetic fiber felt is preferable from the viewpoint of versatility, and polyester fiber felt is more preferable from the viewpoint of heat resistance, flame retardancy, and the like.

When a fibrous material is used for the first sound absorbing layer 11 and the second sound absorbing layer 15, the average fiber diameter of the fibers constituting the fibrous material is preferably in the range of 10 to 30 μm. Further, the thickness of the fibrous material is preferably in the range of 5 to 15 mm. Furthermore, the basis weight of the fibrous material is preferably in the range of 50-1500 g/m ² , more preferably in the range of 100-300 g/m ² , and particularly preferably in the range of 200-280 g/m ² . Furthermore, the average apparent density of the fibrous material is preferably in the range of 0.01 to 0.1 g/cm ³ .

When a foam material having open cells is used as the first sound absorbing layer 11 and the second sound absorbing layer 15, the thickness of the foam material is preferably in the range of 5 to 15 mm. The basis weight of the foam material is preferably in the range of 50-4500 g/m ² , more preferably in the range of 100-2000 g/m ^{2 , and particularly preferably in the range of 100-1000 g/m 2 .} Moreover, the average apparent density of the foam material is preferably in the range of 0.01 to 0.3 g/cm ³ .

By configuring the average fiber diameter, thickness, average apparent density, and basis weight of the fibers of the first sound absorbing layer 11 and the second sound absorbing layer 15 as described above, Sound waves incident on the second sound absorbing layer 15 as well as sound waves transmitted without being absorbed by the second sound absorbing layer 15 and the intermediate layer 13 efficiently pass through the fibrous material or open cells of the first sound absorbing layer 11. A part of the energy of the sound wave can be exchanged with heat energy and consumed by the friction with the peripheral wall of the skeleton, viscous resistance, and vibration of the skeleton. In the first sound absorbing layer 11 and the second sound absorbing layer 15, if the average fiber diameter, thickness, average apparent density, and basis weight of the fibers are less than the above ranges, the sound absorption coefficient may decrease as a whole. be. On the other hand, when the average fiber diameter, thickness, average apparent density, and basis weight of the fibers exceed the above ranges, it is not suitable for thinning and weight reduction.

The air permeability of the first sound absorbing layer 11 and the second sound absorbing layer 15 is not particularly limited, but is preferably equal to or greater than the air permeability of the intermediate layer 13. Specifically, 5 It is preferably in the range of up to 1000 cm ³ /cm ² ·sec, more preferably in the range of 100 to 300 cm ³ /cm ² ·sec. If the air permeability of the first sound absorbing layer 11 and the second sound absorbing layer 15 is less than 5 cm ³ /cm ² ·sec, the sound absorption coefficient of the sound insulating material 10 may decrease as a whole. On the other hand, if the air permeability of the first sound absorbing layer 11 and the second sound absorbing layer 15 exceeds 1000 cm ³ /cm ² ·sec, the handleability and mechanical strength may deteriorate. By configuring the air permeation amounts of the first sound absorbing layer 11 and the second sound absorbing layer 15 in such a manner, not only sound waves that are not absorbed by the skin layer 17 but enter the second sound absorbing layer 15 are That is, the sound waves transmitted through the second sound absorbing layer 15 and the intermediate layer 13 without being absorbed are efficiently transmitted to the fiber material or open-cell foam material of the first sound absorbing layer 11, and part of the sound wave energy is can be exchanged for heat energy and consumed by friction with the peripheral wall of the skeleton, viscous resistance, and vibration of the skeleton.

A manufacturing method of the synthetic fiber felt used for the first sound absorbing layer 11 and the second sound absorbing layer 15 is not particularly limited, and conventionally known manufacturing methods can be mentioned. Specifically, by a dry method (carding method or air-laid method), the above-mentioned synthetic fibers are defibrated and mixed, and formed into a felt-like mat laminated on layers with a felt sorting machine. Synthetic fiber felt can be obtained by performing interlayer stitching by a needle punch method in order to prevent peeling. In addition to the needle punch method, a chemical bond method, a thermal bond method, a hydroentanglement method, or the like may be used for interlayer stitching and interfiber bonding.

The method for producing the open-cell foam material used for the first sound absorbing layer 11 and the second sound absorbing layer 15 is not particularly limited, and conventionally known manufacturing methods can be used. For example, a urethane foam material can be obtained by mixing a polyisocyanate and a polyol with a catalyst, a foaming agent, a foam stabilizer, etc., and carrying out a foaming reaction and a resinification reaction at the same time. In addition, a closed cell type polyolefin foam material is produced in advance, and then subjected to a compression treatment in which it is passed through a gap between two rolls rotating in opposite directions to compress, thereby rupturing the cell membranes and generating cells. It is also possible to obtain an open-cell polyolefin-based foam material by a method of connecting the .

<Skin layer>
The fiber material of the skin layer 17 has an average fiber diameter in the range of 1 to 10 μm and an air permeability in the range of 5 to 200 cm ³ /cm ² ·sec. A fibrous material is a material whose shape is supported by fibers and which has spaces between the fibers through which gas can pass. The fibrous material is preferably sheet-like. Non-woven fabrics, woven fabrics and knitted fabrics are included in the fibrous materials referred to herein. On the contrary, a resin foam or a resin film material is not included in the fibrous material referred to here even if it is a material having air permeability.

By setting the average fiber diameter and air permeability of the skin layer 17 within the above ranges, the fiber material of the skin layer 17 tends to have a relatively dense structure, and the resonance type sound absorbing mechanism and the porous type sound absorbing mechanism can be combined. , that is, the effect of increasing the sound absorption coefficient in the middle to high frequency range. At the same time, the sound absorption coefficient in the frequency band of 2000 Hz or less (middle to low frequency band) can also be raised to a certain level incidentally. Therefore, as described above, when the skin layer 17 is partially bonded onto the second sound absorbing layer 15 via the third bonding layer 16, the third bonding layer 16 and the second sound absorbing layer 15, the sound absorption coefficient in the high frequency band tends to decrease as the bonding area ratio increases, but this phenomenon can be covered by the characteristics of the skin layer 17, that is, the viscous resistance. As a result, even if the soundproof material 10 of the present invention is thin, it is possible to achieve the effect of expanding the frequency band capable of absorbing sound in actual use.

In the present embodiment, the fiber material of the skin layer 17 is not particularly limited, but it is preferable to use a nonwoven fabric made of synthetic fibers. Examples of fibers constituting the nonwoven fabric include polyolefin fibers such as polyethylene, polypropylene and copolymerized polypropylene; polyamide fibers such as nylon 6, nylon 66 and copolymerized polyamide; polyethylene terephthalate, polybutylene terephthalate, copolymerized polyester; Polyester fiber such as aliphatic polyester, acrylic fiber, aramid fiber, composite fiber such as core-sheath structure with polyethylene, polypropylene or copolyester sheath and polypropylene or polyester core, polylactic acid, polybutylene sax Thermoplastic synthetic fibers such as biodegradable fibers such as polystyrene succinate and polyethylene succinate can be used. These fibers can be used singly or in combination of two or more. In addition, modified cross-section fibers such as flat yarns, crimped fibers, split fibers, etc. can be used in combination or in layers. Among these, polyester fibers are particularly preferred from the viewpoint of versatility, heat resistance, flame retardancy, and the like.

The average fiber diameter of the fibers constituting the fiber material of the skin layer 17 is in the range of 1 to 10 μm. The diameter of the fiber constituting the skin layer 17 has a structure with small voids, and increases the sound absorption coefficient in the middle to high frequency band, and at the same time, increases the sound absorption coefficient in the frequency band of 2000 Hz or less (middle and low frequency band) as much as possible. In addition, it is preferable to make it small. The fiber diameters of the fibers constituting the fiber material may be the same or different. When the fiber diameters are different, the fiber material is a mixture of thick fibers with an average fiber diameter of 10 μm or more and thin fibers with an average fiber diameter of less than 1 μm, so that the average fiber diameter is in the range of 1 to 10 μm. I don't mind if you donate. If the average fiber diameter of the fibers constituting the fibrous material is less than 1 μm, the strength, rigidity, handleability, etc. may deteriorate, and the price may be disadvantageous. On the other hand, if the average fiber diameter exceeds 10 μm, the sound absorption coefficient in the middle to high frequency band may decrease, and the sound absorption coefficient in the frequency band of 2000 Hz or less (middle to low frequency band) may also decrease.

The air permeability of the fiber material of the skin layer 17 is in the range of 5 to 200 cm ³ /cm ² ·sec, preferably in the range of 10 to 100 cm ³ /cm ² ·sec, more preferably 20 to 80 cm ³ /sec. It is in the range of cm ² ·sec. If the air permeability of the skin layer 17 is less than 5 cm ³ /cm ² ·sec, the sound absorption coefficient in the medium to high frequency range may decrease. On the other hand, if the air permeability of the skin layer 17 exceeds 200 cm ³ /cm ² ·sec, the sound absorption coefficient in the frequency band of 2000 Hz or less (middle and low frequency band) may decrease.

The thickness of the skin layer 17 is preferably in the range of 0.01 to 5 mm, more preferably in the range of 0.05 to 4 mm. The basis weight of the skin layer 17 is preferably in the range of 5-300 g/m ² , more preferably in the range of 15-100 g/m ² . Furthermore, the average apparent density of the skin layer 17 is preferably in the range of 0.01 to 1.0 g/cm ³ and more preferably in the range of 0.02 to 1.0 g/m ³ .

By setting the thickness, average apparent density, and basis weight of the skin layer 17 as described above, the sound energy of the sound waves that pass through the fiber material is transferred to the air friction in the vicinity of the cavity entrance and the inner wall of the fiber skeleton. It can be consumed more effectively by viscous friction or the like. When the thickness of the skin layer 17 is less than 0.01, the average apparent density is less than 0.01 g/cm ³ , and the basis weight is less than 5 g/m ² , the strength, rigidity, fiber density, etc. are reduced, resulting in poor handleability. And the sound absorption effect may decrease. On the other hand, when the thickness of the skin layer 17 exceeds 5 mm, the average apparent density exceeds 1.0 g/m ³ , and the basis weight exceeds 300 g/m ² , strength and fiber density increase, but rigidity decreases. If it is too large, there is a possibility that the cuttability and handleability may deteriorate. In addition, it is not suitable for thinning and lightening.

The method for producing the fibrous material of the skin layer 17 is not particularly limited, and conventionally known wet methods, dry methods, or methods for producing nonwoven fabrics by direct spinning (spunbond, meltblown, etc.) can be mentioned. Among these, from the viewpoint of strength, handleability, and pore uniformity of the fibrous material, for example, nonwoven fabrics in which the warp and weft yarns are arranged almost perpendicularly or nonwoven fabrics in which the warp yarns are arranged only in one direction or a method for producing a non-woven fabric in which thick fibers and thin fibers are inter-fiber-bonded by a binder, but these are only examples and are not limited to these.

The above-mentioned weft-crossed nonwoven fabric is produced by first stretching fibers directly spun from the above-described raw material resin such as polyester, and then processing and preparing two types of webs in which the fibers are arranged in the vertical and horizontal directions. The web is laminated so that the fibers arranged in the web are perpendicular to each other and joined by point heat fusion by heat embossing. In addition to heat embossing, other methods for laminating vertical and horizontal webs include a method of impregnating and adhering with an emulsion, and a method of entangling short fibers with a water jet to combine and integrate them. Similarly, it is possible to manufacture a nonwoven fabric in which fibers are arranged only in the longitudinal direction, and this nonwoven fabric may be used as a fibrous material. The nonwoven fabric produced by such a method differs from the nonwoven fabric produced by the conventional spunbond method in that ultrafine fibers with an average fiber diameter of several μm are arranged in the vertical and horizontal directions or in the longitudinal direction. Therefore, deformation when a load is applied is small and the shape can be maintained, so secondary processing (roll-to-roll processing) that requires tension can be easily performed even with a low basis weight. The tensile strength (according to ASTM D882) of these nonwoven fabrics is preferably in the range of 20 to 300 N/50 mm in the MD direction.

The non-woven fabric in which the thick fibers and thin fibers are inter-fiber-bonded by a binder is obtained by first cutting fibers having different fiber diameters, which are melt-spun or wet-spun from the above-described raw material resin such as polyester, into flocks having a fiber length of 10 mm or less, for example. , mixed with fibers such as polyvinyl alcohol as a binder to prepare a uniformly dispersed suspension, and then manufactured by a normal papermaking method. The fibers having different fiber diameters may be made of the same material or may be made of different materials. At the time of sheeting, in addition to the papermaking method which is a wet method, a dry method in which short fibers are sheeted by a webber (air laid method) using a carding machine and an air flow may be used. The fiber arrangement may be either cross or random.

<Soundproof material>
The soundproof material 10 of the present invention comprises an intermediate layer 13 made of a fibrous material having a relatively dense structure, a first sound absorbing layer 11 made of a porous material having a coarse structure in which voids are communicated, and a second sound absorbing layer. A first sound absorbing layer 11 is provided on one side of the intermediate layer 13, a second sound absorbing layer 15 is provided on the other side of the intermediate layer 13, and a first bonding layer 12 and a second bonding layer 14, respectively. Furthermore, the skin layer 17 made of a fibrous material with a relatively dense structure is partially bonded to the sound source side surface of the second sound absorbing layer 15 with a third bonding layer 16. be done. As methods for connecting the intermediate layer 13 and the first sound absorbing layer 11, the intermediate layer 13 and the second sound absorbing layer 15, and the skin layer 17 and the second sound absorbing layer 15, as described above, each layer is It is preferable to use a coated adhesive or a double-sided adhesive tape (including a baseless double-sided adhesive tape) to bond them together so as to achieve a predetermined bonding area ratio. Specifically, first, on either side of the first sound absorbing layer 11 or the intermediate layer 13, double-sided adhesive tape (including baseless double-sided tape) slit to a predetermined width, punched double-sided A first bonding layer 12 made of a tape or a release film coated with an adhesive in stripes or dots is adhered or transferred so as to have a predetermined bonding area ratio, and then both layers are pressure-bonded.・Join. The pressure bonding between the intermediate layer 13 and the first sound absorbing layer 11 can be performed without heating in a room temperature environment. However, crimping can also be performed while heating as needed. Next, the second sound absorbing layer 15 is similarly bonded to the surface of the intermediate layer 13 of the laminate composed of the obtained intermediate layer 13 and the first sound absorbing layer 11 with the second bonding layer 14. After pasting or transferring so as to obtain the area ratio, both layers are press-bonded and joined. Next, in the same manner, a skin layer 17 is formed on the sound source side surface of the second sound absorbing layer 15 of the laminate composed of the obtained second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11. After bonding or transferring by the bonding layer 16 of No. 3 so as to have a predetermined bonding area ratio, both layers are press-bonded and bonded.

By configuring in this way, the sound absorption of the soundproof material 10 in the middle to high frequency bands is enhanced. The first sound-absorbing layer and the second sound-absorbing layer are porous materials formed by communicating voids that satisfy the above-described conditions for a sound-absorbing layer. The porous material formed by communicating the voids of the first sound absorbing layer and the second sound absorbing layer may be of the same type or of different types.

The thickness of the soundproof material 10 of the present invention is preferably in the range of 10-30 mm. If the thickness of the soundproof material 10 is less than 10 mm, the sound absorption coefficient may decrease as a whole. On the other hand, if the thickness of the soundproof material 10 exceeds 30 mm, it is not suitable for thinning and lightening.

The soundproof material 10 of the present invention has a normal incident sound absorption coefficient measured in accordance with JIS A1405-2 of 55% or more at all of the center frequencies of 1250, 1600, 2000, 2500, 3150 and 4000 Hz in the /3 octave band. More preferably, it is 55% or more at all of the center frequencies of 1000, 1250, 1600, 2000, 2500, 3150 and 4000 Hz of the 1/3 octave band.

The sound absorption coefficient in the medium frequency range (2000 to 4000 Hz) of the soundproofing material can be improved by increasing the thickness of the soundproofing material and increasing the average apparent density of the surface material, but on the other hand, it is expensive and bulky. problems such as becoming In the present invention, the thickness of the soundproof material and the joints between the intermediate layer and the first sound absorbing layer, the intermediate layer and the second sound absorbing layer, and the skin layer and the second sound absorbing layer constituting the soundproof material By setting the area ratio in the above range, it has a practically effective high level of sound absorption coefficient, and while securing a wide range of sound absorbing frequency range of at least 1250 to 4000 Hz, winding processability, cutting processability, It is possible to obtain a soundproofing material that is excellent in handleability during stacking, transportation, and the like.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these. Each characteristic value of Examples and Comparative Examples was measured by the following method.

(1) Vertical incident sound absorption coefficient Using an acoustic impedance tube (inner diameter: Φ29.0 mm) conforming to JIS A 1405-2, with the second sound absorbing layer on the sound source side, 1/3 octave band center frequency 1000 to 4000 Hz The normal incidence sound absorption coefficient was measured in the frequency range. Specifically, normal incident sound absorption coefficients at 1000, 1250, 1600, 2000, 2500, 3150 and 4000 Hz were measured. The measurement was performed in close contact with a rigid wall without taking an air layer behind it. Judgment as to whether or not it is practically effective as a soundproofing material with an expanded frequency band capable of absorbing sound was evaluated according to the following criteria.

(2) Average fiber diameter A 500-fold enlarged photograph was taken with a microscope, 100 fibers were randomly selected, the average value was obtained, and the average fiber diameter was obtained by rounding off to one decimal place.

(3) Permeability Measured with a Frazier air permeability tester conforming to JIS L 1096. DAP-360 (product model number) manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd. was used as the Frazier air permeability tester. The measurement conditions were a differential pressure of 125 Pa and a measurement hole diameter of Φ70 mm.

(4) Thickness of skin layer, sound absorbing layer and intermediate layer Measured according to JIS-L-1913-B method. The load was 20 kPa for the skin layer and intermediate layer, and 0.02 kPa for the sound absorbing layer.

(5) Fabric weight of skin layer, sound absorbing layer and intermediate layer Measured according to JIS-L-1913.

(6) Thickness of Bonding Layer Measurements were taken at three or more points with a dial gauge at a probe diameter of 10 mm and a final pressure of 0.8 N, and the average value was obtained.

(7) Storage modulus of bonding material (G')
For the material used for the bonding layer, a sample with a thickness of 500 μm was prepared, and the dynamic viscoelasticity was measured using a viscoelasticity measuring device DMA6100 (product name) manufactured by Hitachi High-Tech Science Co., Ltd., and the storage elastic modulus was measured. asked. The measurement conditions are as follows: while applying a shear strain with a frequency of 1 Hz, the heating rate is 5 ° C./min, the temperature is changed from -80 ° C. to 80 ° C., the storage elastic modulus (G ') is measured, and the value at 25 ° C. is measured. asked.

<Example 1>
(middle layer)
As the intermediate layer, a polyester fiber material having an average fiber diameter of 3 μm, an air permeability of 21 cm ³ /cm ² ·sec, a basis weight of 20 g/m ² , an average apparent density of 0.33 g/cm ³ and a thickness of 0.06 mm. was prepared (size 100 mm x 100 mm). In this polyester fibrous material, the fibers are arranged in the longitudinal direction.

(First sound absorbing layer, second sound absorbing layer)
As the first sound absorbing layer and the second sound absorbing layer, the average fiber diameter of 19 μm, the air permeability of 165 cm ³ /cm ² sec, the basis weight of 200 g / m ² , the average apparent density of 0.02 g / cm ³ and the average apparent density of 10 mm A polyester fiber felt having a thickness was prepared (size 100 mm x 100 mm).

(skin layer)
As the skin layer, a polyester fiber material having an average fiber diameter of 3 μm, an air permeability of 21 cm ³ /cm ² ·sec, a basis weight of 20 g/m ² , an average apparent density of 0.33 g/cm ³ and a thickness of 0.06 mm. was prepared (size 100 mm x 100 mm). In this polyester fibrous material, the fibers are arranged in the longitudinal direction.

(Formation and bonding of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 2.6 mm. Spread the felt of the first sound absorbing layer, and stick stick-shaped adhesive tape on its surface so that line (adhesive tape junction) / space (opening) / line = 2.6 mm / 23.6 mm / 2.6 mm were arranged and bonded in parallel to each other to form a first bonding layer (with a separator).

Next, after peeling off the release paper (separator) of the adhesive tape arranged and bonded to the first sound absorbing layer, the fiber material of the intermediate layer is spread and placed on it, and pressed under a normal temperature environment. The layers were bonded.

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive 3.5×10 ⁵ Pa) was cut into bars with widths of 5 mm and 6 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface of the felt in the following manner: line (adhesive tape junction)/space (opening)/line/space/line=6 mm/5.9 mm/5 mm/5. They were arranged and bonded in parallel so as to be 9 mm/6 mm to form a second bonding layer (with a separator).

Next, after peeling off the release paper (separator) of the adhesive tape arranged and bonded to the second sound absorbing layer, the intermediate layer of the laminate of the intermediate layer and the first sound absorbing layer prepared earlier is placed on it. The other surface (the surface to which the first sound absorbing layer is not bonded) was spread out and placed so as to face each other, and the two layers were bonded by pressure bonding under a normal temperature environment.

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 4.8 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is Then, a stick-shaped adhesive tape is arranged and bonded in parallel such that line (adhesive tape joint) / space (opening) / line = 4.8 mm / 19.2 mm / 4.8 mm, and the third A bonding layer (with a separator) was formed.

Next, after peeling off the release paper of the adhesive tape arranged and bonded to the second sound absorbing layer (surface where the intermediate layer is not bonded), the fiber material of the skin layer is spread and placed on it, and A soundproofing material was obtained by bonding both layers by pressure bonding under the environment. This soundproof material was cut into a circular shape of Φ28.8mm as shown in FIG. 1, and used for measurement of the sound absorption coefficient.

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 9%, the bonding area ratio of the second bonding layer was 52%, and the third bonding layer was 22%.

<Example 2>
A soundproof material was obtained in the same manner as in Example 1, except that the second bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 13.85 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface so that line (adhesive tape joint) / space (opening) / line = 13.85 mm / 1.1 mm / 13.85 mm were arranged and bonded in parallel to each other to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed by the adhesive tape had a bonding area ratio of 9%, the second bonding layer had a bonding area ratio of 95%, and the third bonding layer was 22%.

<Example 3>
A soundproof material was obtained in the same manner as in Example 1, except that the first bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The felt of the first sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface so that line (adhesive tape joint) / space (opening) / line = 4.8 mm / 19.2 mm / 4.8 mm were arranged and bonded in parallel to each other to form a first bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 22%, the bonding area ratio of the second bonding layer was 52%, and the third bonding layer was 22%.

<Example 4>
A soundproof material was obtained in the same manner as in Example 3, except that the second bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The felt of the second sound absorbing layer is spread out, and a stick-shaped adhesive tape is applied to the surface of the felt. Arranged and bonded in parallel so that 8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm, the second bonding layer was formed (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 22%, the bonding area ratio of the second bonding layer was 81%, and the third bonding layer was 22%.

<Example 5>
A soundproof material was obtained in the same manner as in Example 3, except that the second bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 13.85 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface so that line (adhesive tape joint) / space (opening) / line = 13.85 mm / 1.1 mm / 13.85 mm were arranged and bonded in parallel to each other to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 22%, the second bonding layer had a bonding area ratio of 95%, and the third bonding layer was 22%.

<Example 6>
A soundproof material was obtained in the same manner as in Example 1, except that the formation of the first bonding layer and the second bonding layer were performed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into bars with widths of 6 mm and 5 mm. The felt of the first sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface of the felt in the following manner: line (adhesive tape junction)/space (opening)/line/space/line=6 mm/5.9 mm/5 mm/5. They were arranged and bonded in parallel so as to have a size of 9 mm/6 mm to form a first bonding layer (with a separator).

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 2.6 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface so that the line (adhesive tape joint) / space (opening) / line = 2.6 mm / 23.6 mm / 2.6 mm were arranged and bonded in parallel to each other to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of φ28.8 mm, the bonding area ratio of the bonding layer formed by the adhesive tape was 52% for the first bonding layer and 9% for the second bonding layer. %, and the bonding area ratio of the third bonding layer was 22%

<Example 7>
A soundproof material was obtained in the same manner as in Example 6, except that the second bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. Spread the felt of the second sound absorbing layer, and stick stick-shaped adhesive tape on its surface so that line (adhesive tape joint) / space (opening) / line = 4.8 mm / 19.2 mm / 4.8 mm were arranged and bonded in parallel to each other to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 52%, the second bonding layer had a bonding area ratio of 22%, and the third bonding layer was 22%.

<Example 8>
A soundproof material was obtained in the same manner as in Example 7, except that the third bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into bars with widths of 6 mm and 5 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is In addition, a stick-shaped adhesive tape is arranged and pasted in parallel so that line (adhesive tape joint) / space (opening) / line / space / line = 6 mm / 5.9 mm / 5 mm / 5.9 mm / 6 mm Together, a third bonding layer (with a separator) was formed.

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 52%, the second bonding layer had a bonding area ratio of 22%, and the third bonding layer was 52%.

<Example 9>
A soundproof material was obtained in the same manner as in Example 6, except that the second bonding layer and the third bonding layer were formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface of the felt in the following manner: line (adhesive tape junction)/space (opening)/line/space/line=4.8 mm/7.2 mm/4. They were arranged and bonded in parallel so as to have a size of 8 mm/7.2 mm/4.8 mm to form a second bonding layer (with a separator).

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 4.8 mm. The other side of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer, and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not joined) is spread, and a rod-shaped of adhesive tape in parallel so that line (adhesive tape junction) / space (opening) / line / space / line = 4.8 mm / 7.2 mm / 4.8 mm / 7.2 mm / 4.8 mm By arranging and bonding, a third bonding layer (with a separator) was formed.

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 52%, the bonding area ratio of the second bonding layer was 43%, and the third bonding layer The bonding area ratio was 43%.

<Example 10>
A soundproof material was obtained in the same manner as in Example 8, except that the second bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into bars with widths of 5 mm and 6 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface of the felt in the following manner: line (adhesive tape junction)/space (opening)/line/space/line=6 mm/5.9 mm/5 mm/5. They were arranged and bonded in parallel so as to be 9 mm/6 mm to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 52%, the second bonding layer had a bonding area ratio of 52%, and the third bonding layer was 52%.

<Example 11>
A soundproof material was obtained in the same manner as in Example 7, except that the first bonding layer and the third bonding layer were formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The felt of the first sound absorbing layer is spread out, and a stick-shaped adhesive tape is applied to the surface of the felt. Arranged and bonded in parallel so that 8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm, the first bonding layer (with separator) was formed.

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 1.2 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is Then, a stick-shaped adhesive tape is arranged and bonded in parallel so that line (adhesive tape joint) / space (opening) / line = 1.2 mm / 26.4 mm / 1.2 mm, and a third A bonding layer (with a separator) was formed.

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 3%.

<Example 12>
A soundproof material was obtained in the same manner as in Example 11, except that the third bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is Then, a stick-shaped adhesive tape is arranged and bonded in parallel such that line (adhesive tape joint) / space (opening) / line = 4.8 mm / 19.2 mm / 4.8 mm, and the third A bonding layer (with a separator) was formed.

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Example 13>
A soundproof material was obtained in the same manner as in Example 11, except that the third bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is Then, stick the stick-shaped adhesive tape so that line (adhesive tape joint) / space (opening) / line / space / line = 4.8 mm / 7.2 mm / 4.8 mm / 7.2 mm / 4.8 mm were arranged and bonded in parallel to each other to form a third bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 43%.

<Example 14>
A soundproof material was obtained in the same manner as in Example 11, except that the third bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is Then, a stick-shaped adhesive tape is arranged in a line (adhesive tape junction)/space (opening)/line/space/line/space/line/space/line=4.8 mm/1.2 mm/4.8 mm/1. They were arranged and bonded in parallel so as to have a size of 2 mm/4.8 mm/1.2 mm/4.8 mm/1.2 mm/4.8 mm to form a first bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 81%.

<Example 15>
A soundproof material was obtained in the same manner as in Example 11, except that the third bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 26.4 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is Then, stick-shaped adhesive tapes are arranged and bonded in parallel so that space (opening) / line (adhesive tape junction) / space (opening) = 1.2 mm / 26.4 mm / 1.2 mm Then, the pressure-sensitive adhesive tape was arranged and bonded to the surface to form a third bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 97%.

<Example 16>
A soundproof material was obtained in the same manner as in Example 13, except that the second bonding layer was formed as follows.
(Formation of bonding layer)

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface of the felt in the following manner: line (adhesive tape junction)/space (opening)/line/space/line=4.8 mm/7.2 mm/4. They were arranged and bonded in parallel so as to have a size of 8 mm/7.2 mm/4.8 mm to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 43%, and the third bonding layer was 43%.

<Example 17>
A soundproof material was obtained in the same manner as in Example 14, except that the second bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The felt of the second sound absorbing layer is spread out, and a stick-shaped adhesive tape is applied to the surface of the felt. Arranged and bonded in parallel so that 8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm / 1.2 mm / 4.8 mm, the second bonding layer was formed (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 81%, and the third bonding layer was 81%.

<Example 18>
A soundproof material was obtained in the same manner as in Example 5, except that the first bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 13.85 mm. Spread the felt of the first sound absorbing layer, and stick stick-shaped adhesive tape on its surface so that line (adhesive tape joint) / space (opening) / line = 13.85 mm / 1.1 mm / 13.85 mm were arranged and bonded in parallel to each other to form a first bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 95%, the second bonding layer had a bonding area ratio of 95%, and the third bonding layer was 22%.

<Example 19>
A soundproof material was obtained in the same manner as in Example 18, except that the second bonding layer was formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 2.6 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface so that the line (adhesive tape joint) / space (opening) / line = 2.6 mm / 23.6 mm / 2.6 mm were arranged and bonded in parallel to each other to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 95%, the second bonding layer had a bonding area ratio of 9%, and the third bonding layer was 22%.

<Example 20>
A soundproof material was obtained in the same manner as in Example 8, except that the first bonding layer and the second bonding layer were formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 1.2 mm. The felt of the first sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface so that line (adhesive tape joint) / space (opening) / line = 1.2 mm / 26.4 mm / 1.2 mm were arranged and bonded in parallel to each other to form a first bonding layer (with a separator).

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 1.2 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is placed on its surface so that line (adhesive tape joint) / space (opening) / line = 1.2 mm / 26.4 mm / 1.2 mm were arranged and bonded in parallel to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed by the adhesive tape had a bonding area ratio of 3%, the second bonding layer had a bonding area ratio of 3%, and the third bonding layer was 52%.

<Example 21>
A soundproof material was obtained in the same manner as in Example 20, except that the third bonding layer was formed as follows.

Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 26.4 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is Then, stick-shaped adhesive tapes are arranged and bonded in parallel so that space (opening) / line (adhesive tape junction) / space (opening) = 1.2 mm / 26.4 mm / 1.2 mm Then, the pressure-sensitive adhesive tape was arranged and bonded to the surface to form a third bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed by the adhesive tape had a bonding area ratio of 3%, the second bonding layer had a bonding area ratio of 3%, and the third bonding layer was 97%.

<Example 22>
A soundproof material was obtained in the same manner as in Example 15, except that the first bonding layer and the second bonding layer were formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 13.85 mm. Spread the felt of the first sound absorbing layer, and stick stick-shaped adhesive tape on its surface so that line (adhesive tape joint) / space (opening) / line = 13.85 mm / 1.1 mm / 13.85 mm were arranged and bonded in parallel to each other to form a first bonding layer (with a separator).

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 26.4 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface of the felt. They were arranged and bonded in parallel so as to have a thickness of 0.2 mm to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 95%, the bonding area ratio of the second bonding layer was 97%, and the third bonding layer was 97%.

<Example 23>
A soundproof material was obtained in the same manner as in Example 8, except that the first bonding layer and the second bonding layer were formed as follows.

(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 1.2 mm. The felt of the first sound absorbing layer is spread, and a bar-shaped adhesive tape is applied to the surface of the felt in the following manner: space (opening)/line (joint of adhesive tape)/space (opening)=1.2 mm/26.4 mm/1. They were arranged and bonded in parallel so as to have a thickness of 2 mm to form a first bonding layer (with a separator).

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 1.2 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface of the felt. They were arranged and bonded in parallel so as to have a thickness of 0.2 mm to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 97%, the second bonding layer had a bonding area ratio of 97%, and the third bonding layer was 52%.

<Example 24>
A soundproof material was obtained in the same manner as in Example 3, except that the intermediate layer and the skin layer were as follows.

(Intermediate layer and epidermis layer)
As the intermediate layer and the ^{skin layer , acrylic} / A polyester blend fiber material was prepared (size 100 mm x 100 mm). In this acrylic/polyester mixed fiber material, the mixing ratio of acrylic fiber and polyester fiber is acrylic fiber/polyester fiber=63/37 (mass ratio), and the fiber arrangement is random.

The total thickness of the resulting soundproof material was 29.5 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 22%, the bonding area ratio of the second bonding layer was 52%, and the third bonding layer was 22%.

<Example 25>
A soundproof material was obtained in the same manner as in Example 7, except that the intermediate layer and the skin layer were as follows.

(Intermediate layer and epidermis layer)
As the intermediate layer and the ^{skin layer , acrylic} / A polyester blend fiber material was prepared (size 100 mm x 100 mm). In this acrylic/polyester mixed fiber material, the mixing ratio of acrylic fiber and polyester fiber is acrylic fiber/polyester fiber=63/37 (mass ratio), and the fiber arrangement is random.

The total thickness of the resulting soundproof material was 29.5 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 52%, the second bonding layer had a bonding area ratio of 22%, and the third bonding layer was 22%.

<Example 26>
A soundproof material was obtained in the same manner as in Example 16, except that the intermediate layer and the skin layer were as follows.

(Intermediate layer and epidermis layer)
As the skin layer, an acrylic/polyester mixed fiber having an average fiber diameter of 10 μm, an air permeability of 80 cm ³ /cm ² sec, a basis weight of 94 g/m ² , an average apparent density of 0.02 g/cm ³ and a thickness of 4 mm. A material was prepared (size 100 mm x 100 mm). In this acrylic/polyester mixed fiber material, the mixing ratio of acrylic fiber and polyester fiber is acrylic fiber/polyester fiber=63/37 (mass ratio), and the fiber arrangement is random.

The total thickness of the resulting soundproof material was 29.5 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 43%, and the third bonding layer was 43%.

<Example 27>
As a bonding material for the first bonding layer, the second bonding layer, and the third bonding layer, a baseless double-sided adhesive tape "KF4#100" (trade name, Substrate: none, adhesive tape thickness: 0.1 mm, double-sided separator, storage elastic modulus of adhesive: 1.1 × ¹⁰ Pa) was used in the same manner as in Example 12 to obtain a soundproof material. rice field.

The total thickness of the resulting soundproof material was 20.4 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Example 28>
As a bonding material for the first bonding layer, the second bonding layer, and the third bonding layer, an acrylic pressure-sensitive adhesive (2-methoxyethyl acrylate/2-ethylhexyl acrylate/4-hydroxybutyl acrylate/hexamethylene diisocyanate crosslinked Agent = 40 parts by mass / 59 parts by mass / 1 part by mass / 0.7 parts by mass) double-sided adhesive tape without substrate (base material: none, adhesive tape thickness: 0.1 mm, with double-sided separator, adhesive A soundproof material was obtained in the same manner as in Example 12, except that a storage elastic modulus of 6.0 × 10 ⁴ Pa) was used.

The total thickness of the resulting soundproof material was 20.4 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Example 29>
As a bonding material for the first bonding layer, the second bonding layer, and the third bonding layer, the double-sided adhesive tape "No. 5933 Super Butyl Tape" (trade name, base material A soundproof material was obtained in the same manner as in Example 12, except that polyethylene net, adhesive tape thickness: 3.0 mm, single-sided separator, storage elastic modulus of adhesive: 3.6×10 ⁵ Pa) was used.

The total thickness of the resulting soundproof material was 29.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Example 30>
A soundproof material was obtained in the same manner as in Example 12, except that the intermediate layer and the skin layer were as follows.

(Intermediate layer and epidermis layer)
The intermediate layer and skin layer have an average fiber diameter of 6 μm, an air permeability of 9 cm ³ /cm ² ·sec, a basis weight of 60 g/m ² , an average apparent density of 0.12 g/cm ³ and a thickness of 0.5 mm. An acrylic/polyester mixed fiber material was prepared (size 100 mm x 100 mm). In this acrylic/polyester mixed fiber material, the mixing ratio of the acrylic fiber and the polyester fiber is acrylic fiber/polyester fiber=80/20 (mass ratio), and the fiber arrangement is random.

The total thickness of the resulting soundproof material was 22.5 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Example 31>
A soundproof material was obtained in the same manner as in Example 12, except that the intermediate layer and the skin layer were as follows.

(Intermediate layer and epidermis layer)
The intermediate layer and skin layer have an average fiber diameter of 10 μm, an air permeability of 190 cm ³ /cm ² ·sec, a basis weight of 85 g/m ² , an average apparent density of 0.14 g/cm ³ and a thickness of 0.6 mm. A polyester fiber material was prepared (size 100 mm x 100 mm). The fibers of this polyester fiber material are randomly arranged.

The total thickness of the resulting soundproof material was 22.7 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Example 32>
A soundproof material was obtained in the same manner as in Example 12, except that the first sound absorbing layer and the second sound absorbing layer were as follows.

(First sound absorbing layer and second sound absorbing layer)
As the first sound absorbing layer and the second sound absorbing layer, the average fiber diameter of 19 μm, the air permeability of 265 cm ³ /cm ² · sec, the basis weight of 100 g / m ² , the average apparent density of 0.02 g / cm ³ and the average apparent density of 5 mm A polyester fiber felt having a thickness was prepared (size 100 mm x 100 mm).

The total thickness of the resulting soundproof material was 11.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Example 33>
A soundproof material was obtained in the same manner as in Example 12, except that the first sound absorbing layer and the second sound absorbing layer were as follows.

(First sound absorbing layer and second sound absorbing layer)
As the first sound absorbing layer and the second sound absorbing layer, the average fiber diameter of 19 μm, the air permeability of 113 cm ³ /cm ² · sec, the basis weight of 280 g / m ² , the average apparent density of 0.02 g / cm ³ and the average apparent density of 14 mm A polyester fiber felt having a thickness was prepared (size 100 mm x 100 mm).

The total thickness of the obtained soundproof material was 29.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Example 34>
A soundproof material was obtained in the same manner as in Example 16, except that the following intermediate layer was used.

(middle layer)
The intermediate layer is a polyester fiber material having an average fiber diameter of 17 μm, an air permeability of 197 cm ³ /cm ² ·sec, a basis weight of 85 g/m ² , an average apparent density of 0.14 g/cm ³ and a thickness of 0.6 mm. was prepared (size 100 mm x 100 mm).

The total thickness of the resulting soundproof material was 22.2 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 43%, and the third bonding layer was 43%.

<Comparative Example 1>
The first sound absorbing layer with a thickness of 10 mm used in Example 1 was used as a soundproof material.

<Comparative Example 2>
The following first sound absorbing layer having a thickness of 20 mm was used as a sound insulating material.

(First sound absorbing layer)
As the first sound absorbing layer, a polyester fiber having an average fiber diameter of 19 μm, an air permeability of 96 cm ³ /cm ² ·sec, a basis weight of 400 g/m ² , an average apparent density of 0.02 g/cm ³ and a thickness of 20 mm A felt was prepared (size 100 mm x 100 mm).

<Comparative Example 3>
On the first sound absorbing layer used in Comparative Example 2, as a second sound absorbing layer, the first sound absorbing layer used in Example 1 was simply superimposed without being joined with an adhesive tape to form a soundproof material. and The total thickness of the soundproof material was 30 mm.

<Comparative Example 4>
The first sound absorbing layer, the intermediate layer, the second sound absorbing layer, and the skin layer used in Example 1 were simply layered in this order without bonding with a bonding layer to form a soundproof material. The total thickness of the soundproof material was 20.1 mm.

<Comparative Example 5>
A soundproof material was obtained in the same manner as in Example 1, except that the formation and bonding of the first bonding layer, the second bonding layer, and the third bonding layer were as follows.

(Formation and bonding of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into a size of 100 mm×100 mm. The felt of the first sound absorbing layer was spread, and the adhesive tape was placed and bonded on the surface to form the first joining layer (with a separator).

Next, after peeling off the release paper of the adhesive tape arranged and bonded to the first sound absorbing layer, the fiber material of the intermediate layer is spread and placed on it, and the two layers are bonded by pressing under a normal temperature environment. did.

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a size of 100 mm×100 mm. The felt of the second sound absorbing layer was spread, and the adhesive tape was arranged and bonded on the surface to form the second bonding layer (with a separator).

Next, after peeling off the release paper (separator) of the adhesive tape arranged and bonded to the second sound absorbing layer, the intermediate layer of the laminate of the intermediate layer and the first sound absorbing layer prepared earlier is placed on it. The other surface (the surface to which the first sound absorbing layer is not bonded) was spread out and placed so as to face each other, and the two layers were bonded by pressure bonding under a normal temperature environment.

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 4.8 mm. The other surface of the second sound absorbing layer of the laminate of the first sound absorbing layer, the intermediate layer and the second sound absorbing layer prepared earlier (the surface to which the intermediate layer is not bonded) is laid out, and the surface is , the adhesive tape was arranged and bonded to form a third bonding layer (with a separator).

Next, after peeling off the release paper of the adhesive tape arranged and bonded to the second sound absorbing layer (surface where the intermediate layer is not bonded), the fiber material of the skin layer is spread and placed on it, and A soundproofing material was obtained by bonding both layers by pressure bonding under the environment. This soundproof material was cut into a circular shape of Φ28.8mm as shown in FIG. 1, and used for measurement of the sound absorption coefficient.

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed by the adhesive tape had a bonding area ratio of 100%, the second bonding layer had a bonding area ratio of 100%, and the third bonding layer was 100%.

<Comparative Example 6>
A soundproof material was obtained in the same manner as in Example 11, except that the first bonding layer and the second bonding layer were formed as follows.
(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. The felt of the first sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface of the felt in the following manner: line (adhesive tape junction)/space (opening)/line/space/line=4.8 mm/7.2 mm/4. They were arranged and bonded in parallel so as to have a size of 8 mm/7.2 mm/4.8 mm to form a first bonding layer (with a separator).

Next, Maxell's double-sided adhesive tape "No. 5938 super butyl tape" using a butyl rubber adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elasticity of adhesive (ratio: 3.5×10 ⁵ Pa) was cut into a bar shape with a width of 1.2 mm. Spread the felt of the second sound absorbing layer, and stick stick-shaped adhesive tape on its surface so that line (adhesive tape junction) / space (opening) / line = 1.2 mm / 26.4 mm / 1.2 mm were arranged and bonded in parallel to each other to form a second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 43%, the bonding area ratio of the second bonding layer was 3%, and the third bonding layer was 3%.

<Comparative Example 7>
A soundproof material was obtained in the same manner as in Example 7, except that the first bonding layer was formed as follows.
(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 4.8 mm. Spread the felt of the second sound absorbing layer, and stick stick-shaped adhesive tape on its surface so that line (adhesive tape joint) / space (opening) / line = 4.8 mm / 19.2 mm / 4.8 mm were arranged and bonded in parallel to each other to form a first bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 22%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Comparative Example 8>
A soundproof material was obtained in the same manner as in Example 6, except that the first bonding layer was formed as follows.
(Formation of bonding layer)
Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into rods with a width of 23.6 mm. The felt of the second sound absorbing layer is spread, and a stick-shaped adhesive tape is applied to the surface so that the line (adhesive tape joint) / space (opening) / line = 2.6 mm / 23.6 mm / 2.6 mm were arranged and bonded in parallel to each other to form a first bonding layer.

The total thickness of the resulting soundproof material was 21.6 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed of the adhesive tape had a bonding area ratio of 9%, the second bonding layer had a bonding area ratio of 9%, and the third bonding layer was 22%.

<Comparative Example 9>
A soundproof material was obtained in the same manner as in Example 22, except that the second bonding layer was formed as follows.

Double-sided adhesive tape "No. 5938 Super Butyl Tape" manufactured by Maxell using a butyl rubber-based adhesive (trade name, base material: polyethylene net, adhesive tape thickness: 0.5 mm, single-sided separator, storage elastic modulus of adhesive: 3.5×10 ⁵ Pa) was cut into a size of 100 mm×100 mm. The felt of the second sound absorbing layer was spread, and the adhesive tape was arranged and bonded on the surface to form the second bonding layer (with a separator).

The total thickness of the resulting soundproof material was 21.6 mm. Further, in the sound absorption coefficient measurement sample of Φ28.8 mm, the first bonding layer formed by the adhesive tape had a bonding area ratio of 95%, the second bonding layer had a bonding area ratio of 100%, and the third bonding layer was 97%.

<Comparative Example 10>
A soundproof material was obtained in the same manner as in Example 12, except that the intermediate layer and the skin layer were as follows.

(Intermediate layer and epidermis layer)
The intermediate layer and skin layer have an average fiber diameter of 17 μm, an air permeability of 197 cm ³ /cm ² ·sec, a basis weight of 85 g/m ² , an average apparent density of 0.14 g/cm ³ and a thickness of 0.6 mm. A polyester fiber material was prepared (size 100 mm x 100 mm).

The total thickness of the resulting soundproof material was 22.7 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 81%, the bonding area ratio of the second bonding layer was 22%, and the third bonding layer was 22%.

<Comparative Example 11>
A soundproof material was obtained in the same manner as in Example 22, except that the following intermediate layer was used.

(middle layer)
As an intermediate layer, a closed-cell type polyethylene foam material having an air permeability of 0.2 cm ³ /cm ² ·sec, a basis weight of 66 g/m ² , an average apparent density of 0.03 g/cm ³ and a thickness of 2 mm is prepared. did.

The total thickness of the resulting soundproof material was 23.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 95%, the bonding area ratio of the second bonding layer was 97%, and the third bonding layer was 97%.

<Comparative Example 12>
A soundproof material was obtained in the same manner as in Example 22, except that the following intermediate layer was used.

(middle layer)
A polyethylene film material having a basis weight of 46 g/m ² , an average apparent density of 0.92 g/cm ³ and a thickness of 0.05 mm was prepared as an intermediate layer.

The total thickness of the resulting soundproof material was 21.6 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed by the adhesive tape was 95%, the bonding area ratio of the second bonding layer was 97%, and the third bonding layer was 97%.

Tables 1 to 7 show the structure and measurement results of normal incidence sound absorption coefficients for each of the soundproof materials of Examples 1 to 34 and Comparative Examples 1 to 12.

As is clear from Tables 1 to 7, all the soundproofing materials of Examples 1 to 34 of the present invention have a normal incident sound absorption coefficient of 1/3 octave even though the total thickness is thin in the range of 10 to 30 mm. It is a practically effective high level of 55% or more at all of the band center frequencies of 1250, 1600, 2000, 2500, 3150 and 4000 Hz. In Examples 19, 22 to 26, and 29 and 33, the normal incident sound absorption coefficient is 55% or more at all of the center frequencies of 1000, 1250, 1600, 2000, 2500, 3150 and 4000 Hz in the 1/3 octave band. It can be seen that the sound absorbing frequency band effective as a soundproof material with an expanded sound absorbing frequency band is also expanded further.

The examples are compared in detail below. In Example 1 and Example 2, in which the first bonding layer has a bonding area ratio of 9% and the third bonding layer has a bonding area ratio of 22%, the second bonding layer has a bonding area ratio of 95%. In Example 2, compared with Example 1 in which the second bonding layer has a bonding area ratio of 52%, the sound absorbing frequency band effective as a soundproof material (a frequency band in which the normal incidence sound absorption coefficient is 55% or more) is seen to expand further.

Further, in Examples 3 to 5 in which the bonding area ratio of the first bonding layer is 22% and the bonding area ratio of the third bonding layer is the same as 22%, the bonding area ratio of the second bonding layer is 81% and 95%, respectively. %, the sound absorption frequency band effective as a soundproof material (normal incidence sound absorption coefficient is 55% It can be seen that the above frequency band) has expanded further.

Further, in Examples 7 and 12 in which the second bonding layer had a bonding area ratio of 22% and the third bonding area ratio was 22%, the bonding area ratio of the first bonding layer was 81%. In Example 12, compared with Example 7 in which the bonding area ratio of the first bonding layer was 52%, the sound absorption frequency band effective as a soundproof material (frequency band in which the normal incidence sound absorption coefficient was 55% or more) was Although they are the same, it can be seen that the normal incidence sound absorption coefficient values are relatively high.

In Examples 11 to 15 in which the first bonding layer has a bonding area ratio of 81% and the second bonding layer has a bonding area ratio of 22%, the third bonding layer has a bonding area ratio of 81%. , 97%, compared with Examples 11, 12, and 13 in which the bonding area ratio of the third bonding layer is 3%, 22%, and 43%, It can be seen that although the normal incidence sound absorption coefficient in the high frequency band is slightly lowered, the sound absorption frequency band effective as a soundproof material (the frequency band in which the normal incidence sound absorption coefficient is 55% or more) is expanded.

Furthermore, the intermediate layer and skin layer have an average fiber diameter of 10 μm, an air permeability of 80 cm ³ /cm ² sec, a basis weight of 94 g/m ² , an average apparent density of 0.02 g/cm ³ and a thickness of 4 mm. Examples 24 to 26 using an acrylic/polyester mixed fiber material having the same joint area ratio of the first to third joint layers, although the total thickness is also affected, Example 3, Example 7. Compared to Example 16, the effective sound absorption frequency band as a soundproofing material (frequency band in which the normal incidence sound absorption coefficient is 55% or more) is expanded, and the sound absorption characteristics in the low to high frequency bands are well balanced. It is understood that

Furthermore, the first bonding layer has a bonding area ratio of 81%, the second bonding layer has a bonding area ratio of 22%, and the third bonding layer has a bonding area ratio of 22%. In Example 12 and Examples 27 to 29 with different thicknesses, Examples 27 to 29 all exhibit good sound absorption characteristics like Example 12, but Examples 27 and 28 are: Since the storage elastic modulus of the bonding layer was slightly lower than that of Example 12, the normal incidence sound absorption coefficient was slightly lower in the frequency band of 2000 Hz or higher. In addition, in Example 29 in which the thickness of the bonding material is 3 mm, the weight of the bonding layer is larger than in Examples 12, 27, and 28, and the air layer (opening portion) formed by the bonding layer ), the sound absorption frequency band effective as a soundproof material (frequency band in which the normal incidence sound absorption coefficient is 55% or more) is expanded.

Furthermore, Example 12, Example 30, and Example 30, in which the bonding area ratio of the first bonding layer is 81%, the bonding area ratio of the second bonding layer is 22%, and the third bonding area ratio is 22%, are the same. Example 12 in which the air permeability of the intermediate layer and the skin layer is 21 cm ³ /cm ² ·sec in Example 31, Example 30 in which the air permeability of the intermediate layer and the skin layer is 9 cm ³ /cm ² ·sec, It can be seen that the normal incidence sound absorption coefficient is relatively high compared to Example 31 in which the air permeability of the intermediate layer and the skin layer is 190 cm ³ /cm ² ·sec.

Furthermore, Example 12, Example 32 and In Example 33, Example 12, in which the basis weight of the first and second sound absorbing layers is ²⁰⁰ g/ ^m2 , is Example 32, in which the basis weight of the first sound absorbing layer and the second sound absorbing layer is 100 g/m2. It can be seen that the normal incidence sound absorption coefficient is relatively high compared to . Similarly, in Example 33 in which the basis weight of the first and second sound absorbing layers is 280 g/m ² , the basis weights of the first and second sound absorbing layers are 200 g/m ² and 100 g/m ² , respectively. It can be seen that the sound absorption frequency band effective as a soundproof material (the frequency band in which the normal incidence sound absorption coefficient is 55% or more) is expanded as compared with Examples 12 and 32.

Furthermore, in Example 16 and Example 34 in which the bonding area ratio of the first bonding layer is 81%, the bonding area ratio of the second bonding layer is 43%, and the third bonding area ratio is 43%. , as an intermediate layer, a polyester fiber having an average fiber diameter of 3 μm, an air permeability of 21 cm ³ /cm ² · sec, a basis weight of 20 g / m ² , an average apparent density of 0.33 g / cm ³ and a thickness of 0.06 mm In Example 16 using the material, the intermediate layer has an average fiber diameter of 17 μm, an air permeability of 197 cm ³ /cm ² ·sec, a basis weight of 85 g/m ² , an average apparent density of 0.14 g/cm ³ and an average apparent density of 0.14 g/cm 3 . Compared to Example 34, which uses a polyester fiber material having a thickness of 6 mm, the intermediate layer has a smaller average fiber diameter and a denser structure. is 55% or more) is expanded more.

On the other hand, all of the soundproofing materials of Comparative Examples 1 to 12, which do not satisfy the scope of the present invention, have relatively low normal incidence sound absorption coefficients compared to Examples 1 to 34. It can be seen that the effective sound absorption frequency band (frequency band in which the normal incident sound absorption coefficient is 55% or more) is narrow, or the balance of sound absorption characteristics in low to high frequency bands is poor.

Comparative Examples 1 to 3 have a structure with only a sound absorbing layer and do not satisfy the structure of the present invention. ) is also narrow.

In addition, in Comparative Examples 4 to 9, since the bonding area ratio of the bonding layer does not satisfy the scope of the present invention, the sound absorbing frequency band effective as a soundproof material (the frequency band in which the normal incidence sound absorption coefficient is 55% or more) is narrow. I understand.

Furthermore, in Comparative Example 10, since the average fiber diameter of the skin layer does not satisfy the scope of the present invention, the sound absorbing frequency band effective as a soundproof material (the frequency band in which the normal incidence sound absorption coefficient is 55% or more) is narrow. I understand.

Furthermore, in Comparative Examples 11 and 12, the intermediate layer is not the fiber material of the present invention, but a foam material with extremely low air permeability and a non-air-permeable film material, respectively. It can be seen that (the frequency band in which the normal incident sound absorption coefficient is 55% or more) is narrow.

INDUSTRIAL APPLICABILITY The present invention can provide a soundproof material that has a practically effective level of high sound absorption coefficient while maintaining its thinness, and that has an expanded sound absorbing frequency range.

Reference Signs List 10, 30 soundproof material 11 first sound absorbing layer 12 first bonding layer 13 intermediate layer 14 second bonding layer 15 second sound absorbing layer 16 third bonding layer 17 skin layer 18, 19, 20 ventilation openings Department

Claims (14)

having a first sound absorbing layer, a first bonding layer, an intermediate layer, a second bonding layer, a second sound absorbing layer, a third bonding layer, and a skin layer laminated in order;
The first sound absorbing layer and the second sound absorbing layer are each independently made of a porous material in which voids are communicated,
The porous material in which the voids of the first sound absorbing layer and the second sound absorbing layer communicate with each other is a fiber material having a basis weight of 50 to 1500 g/m ² ,
The intermediate layer is made of a fibrous material having an average fiber diameter of 1 to 17 μm and an air permeability of 5 to 200 cm ³ /cm ² ·sec,
The skin layer is made of a fibrous material having an average fiber diameter of 1 to 10 μm and an air permeability of 5 to 200 cm ³ /cm ² ·sec,
S1 is the bonding area ratio to the entire contact surface between the first sound absorbing layer and the intermediate layer in the first bonding layer, and the contact surface between the second sound absorbing layer and the intermediate layer in the second bonding layer S2 is the bonding area ratio to the whole, and S3 is the bonding area ratio to the entire contact surface between the skin layer and the second sound absorbing layer in the third bonding layer. A soundproofing material in which the joint area ratio of any one is in the range of 52 to 95% and the joint area ratio of the remaining two is in the range of 3 to 97%. 2. The sound deadening material according to claim 1, wherein said fibrous material of said intermediate layer is a thermoplastic synthetic fiber. Any one of S1, S2, and S3 has a bonding area ratio in the range of 80 to 95%, and the remaining two bonding area ratios range from 3 to 97%. Item 2. The soundproof material according to item 2. Any two of the S1, S2, and S3 have a bonding area ratio in the range of 80 to 95%, and the remaining one has a bonding area ratio in the range of 3 to 97%. Item 2. The soundproof material according to item 2. The bonding material used in the first bonding layer, the second bonding layer, and the third bonding layer is a coated adhesive or double-sided adhesive tape according to any one of claims 1 to 4 . Soundproofing material as described in paragraph. 6. The soundproof material according to claim 5 , wherein the coated adhesive or the adhesive of the double-sided adhesive tape has a shear storage elastic modulus at 25° C. in the range of 1.0×10 ⁴ to 1.0×10 ⁶ Pa. . The soundproof material according to any one of claims 1 to 6, wherein the first bonding layer, the second bonding layer, and the third bonding layer are formed from a plurality of rod-shaped layers. The soundproofing material according to claim 7 , wherein the plurality of bar-shaped layers form a striped pattern. 9. The soundproof material according to claim 8 , wherein the distance between adjacent bar-shaped layers is 1 mm or more. The soundproof material according to any one of claims 1 to 9 , wherein at least one selected from the group consisting of the intermediate layer and the skin layer has an air permeability of 10 to 100 ^cm3 / ^cm2 ·sec. The soundproof material according to any one of claims 1 to 10, wherein the total thickness of the soundproof material is 10 to 30 mm. The soundproof material has a normal incident sound absorption coefficient measured in accordance with JIS A1405-2 of 55% or more at all center frequencies of 1250, 1600, 2000, 2500, 3150 and 4000 Hz in the 1/3 octave band. 12. The soundproof material according to any one of 1 to 11. The soundproof material has a normal incident sound absorption coefficient measured in accordance with JIS A1405-2 of 55% or more at all center frequencies of 1000, 1250, 1600, 2000, 2500, 3150 and 4000 Hz in the 1/3 octave band. The soundproof material according to any one of claims 1-11. The porous material in which the voids of the first sound absorbing layer and the second sound absorbing layer communicate with each other is a fibrous material having a basis weight of 100 to 300 g/m ² . soundproofing material described in .

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