JP7186045B2 - 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. A sound absorbing layer consisting of The inventors have found that it is effective as a soundproofing material having a sound absorption coefficient and 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, and a second sound absorbing layer laminated in order, and the first sound absorbing layer and the second sound absorbing layer The two sound absorbing layers 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 an air permeability of 5 to 200 cm ³ /cm ² ·sec. S1 is a bonding area ratio of the entire contact surface between the first sound absorbing layer and the intermediate layer in the first bonding layer, and the second sound absorbing layer and the intermediate layer in the second bonding layer. When the bonding area ratio of the entire contact surface with the layer is S2, the bonding area ratio of either S1 or S2 is in the range of 5 to 95%, and the bonding area ratio of the other is , in the range of 52-95%.

In one embodiment, the bonding area ratio of one of S1 and S2 is in the range of 5 to 95%, and the bonding area ratio of the other is in the range of 80 to 95%.

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 certain form, the said 1st joining layer and the 2nd joining layer are formed from several 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, the intermediate 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% or more at all center frequencies of 1600, 2000, 2500, 3150 and 4000 Hz in the 1/3 octave band. is.

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 soundproofing 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. is 55% or more.

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, laminated on the other side of the bonding material, and a bonding material laminated between the intermediate layer 13 and the first sound absorbing layer and a second bonding layer 14 laminated between the intermediate layer and the second sound absorbing layer. Furthermore, the soundproof material 10 has an opening 16 without a bonding material between the intermediate layer 13 and the first sound absorbing layer 11, and an opening 16 between the intermediate layer 13 and the second sound absorbing layer 15. It has an opening 17 with no bonding material. 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 and the second bonding layer 14 are layers for bonding the intermediate layer 13 and the first sound absorbing layer 11, and the intermediate layer 13 and the second sound absorbing layer 15, respectively. When the layer 13 and the first sound absorbing layer 13, and the intermediate layer 13 and the second sound absorbing layer 15 are laminated, a bonding material is used on the contact surfaces that come into contact with each other, so that the bonding area ratio is within the range of a predetermined bonding area ratio described later. form like 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, it is preferable to form the first bonding layer 12 and the second bonding layer 14 with a coated adhesive or double-sided adhesive tape (including baseless double-sided adhesive tape). is preferred.

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, a rubber adhesive or an acrylic adhesive is preferable from the viewpoints of versatility, a wide range of variable thickness, and not excessively restricting the intermediate layer and the sound absorbing 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 second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11 can be deformed or displaced to some extent by sound vibration, and the boundary layer Sound waves can be transmitted to some extent without creating a hard part that reflects sound in the can function without 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 and the second bonding layer 14 are for bonding and fixing the intermediate layer 13 and the first sound absorbing layer 11 and the intermediate layer 13 and the second sound absorbing layer 15 as described above. However, here, the present inventors have proposed a first sound absorbing layer 13 made of a fibrous material having a structure having a specific average fiber diameter and air permeability, and a porous material having voids communicating with each other. When the layer 11 and the second sound absorbing layer 15 are 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 second bonding When the bonding area ratio of the entire contact surface between the intermediate layer 13 and the second sound absorbing layer 15 in the layer 14 is S2, one of the bonding area ratio S1 and the bonding area ratio S2 is 5 to 95%. range, and the other is in the range of 52 to 95%. Compared to the soundproofing material of , even if the thickness of the soundproofing material is thin, the frequency at which the normal incidence sound absorption coefficient is maximized (sound absorption peak frequency) can be shifted in the direction of low 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 sound absorption peak frequency. In other words, the present inventors have found that there is an effect of 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 the porous material with communicating voids, generally, the thickness of the first sound absorbing layer 11 alone is increased, or the thickness of the second sound absorbing layer is increased. It is effective to increase the total thickness of a laminate in which the sound absorbing layer 15 is simply superimposed on the first sound absorbing layer 11. is difficult to increase sufficiently. 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 has a relatively dense structure. It is presumed to have a sound absorption characteristic that is a combination of the quality type sound absorption mechanism, and the area where the fiber and the vibrating air (sound waves) contact and the flow resistance tend to be relatively large, and the sound absorption coefficient in the medium to high frequency range has the effect of increasing Therefore, if a laminated body is formed by simply stacking 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 first sound absorbing layer 11 alone , or a laminated 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 middle to high frequency band increases, and the sound absorption in the low to middle frequency band increases. rate also increases concomitantly. However, the sound absorption coefficient in the frequency band below 1600 Hz is still low. Therefore, in order to increase the sound absorption coefficient in the frequency band of 1600 Hz or less, each layer of the second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11 is combined with a second bonding layer 14 such as an adhesive, and When the entire surface is bonded by the first bonding layer 12 (bonded area ratio = 100%), and the membrane vibration type sound absorbing mechanism at each bonding interface is used to shift the sound absorption peak frequency toward lower frequencies, the sound absorption peak frequency is certainly Although the sound absorption coefficient in the vicinity of the sound absorption peak frequency also increases, the sound absorption coefficient in the high frequency band decreases.

In the present invention, the second bonding layer 14 is used to bond the second sound absorbing layer 15 and the intermediate layer 13, and the first bonding layer 12 is used to bond the first sound absorbing layer 11 and the intermediate layer 13 over the entire surface. Instead, S2 is the bonding area ratio with respect to the entire contact surface between the intermediate layer 13 and the second sound absorbing layer 15 in the second bonding layer 14, and the intermediate layer 13 in the first bonding layer 12 and the first sound absorbing layer When the bonding area ratio of the entire contact surface with the layer 11 is S1, one of the bonding area ratio S2 and the bonding area ratio S1 is in the range of 5 to 95%, and the other is in the range of 52 to 95%. In other words, the opening 17 in the second bonding layer 14 has a predetermined range of opening ratio (=100%−bonding area ratio S2), and the first bonding layer 12 has a predetermined opening ratio. By configuring the openings 16 so that the opening ratio (= 100% - bonding area ratio S1) is in the range, the sound waves transmitted without being absorbed by the second sound absorbing layer 15 enter the intermediate layer 13. In addition, the sound wave transmitted without being absorbed by the second sound absorbing layer 15 and the intermediate layer 13 can enter the first sound absorbing layer 11, so that the intermediate layer 13 and the first sound absorbing layer It is possible to transmit the sound wave that has penetrated into the skeleton of the layer 11 to vibrate it, and to efficiently convert the 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 second bonding layer 14 and the first bonding layer 12 are made of a viscoelastic adhesive, the second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11 is not excessively constrained, deformation and displacement due to sound vibration of the second sound absorbing layer 15, the intermediate layer 13, and the first sound absorbing layer 11 are possible to some extent, and the boundary layer produces a hard portion that reflects sound. Therefore, the sound absorbing mechanism of the second sound absorbing layer 15, the intermediate layer 13, the first sound absorbing layer 11, and the sound insulating material 10 as a whole can function without problems. Furthermore, by providing such openings 16 and 17, the laminated structure portion having the bonding layer 12, the first sound absorbing layer 11, and the openings 16, the bonding layer 14, the intermediate layer 13, and the openings 17 At least one of the laminated structure portions has (1) a total opening ratio of the air-permeable openings 16 (opening ratio = 100% - bonding area ratio S1) of 5 to 48%. A sound absorbing layer having a Helmholtz resonator type sound absorbing mechanism provided with a porous material (first sound absorbing layer 11) in which voids are communicated on the back surface of the perforated viscoelastic film (bonding layer 12), or (2 ) Instead of an air layer, Since it can be regarded as a type of sound absorbing layer having a Helmholtz resonator-type sound absorbing mechanism with a directly bonded fiber material (intermediate layer 13) having a relatively dense structure, the sound absorption peak frequency is shifted to the low frequency side. It is possible to maintain to some extent the ability to Note that increasing the bonding area ratios of the first bonding layer 12 and the second bonding layer 14 means that the surface density of each bonding layer increases and the aperture ratio of each bonding layer decreases. 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 surface density increases. Therefore, if both the bonding area ratio S1 of the first bonding layer 12 and the bonding area ratio S2 of the second bonding layer are less than 52%, the effect of increasing the surface density becomes insufficient, and the soundproof material 10 , it is considered that the sound absorption coefficient in the frequency band of 1600 Hz or less does not increase sufficiently. Therefore, in order to expand the frequency band that can absorb sound while balancing the sound absorption coefficient, either one of the bonding area ratio S2 and the bonding area ratio S1 should be in the range of 5 to 95% as described above. It is important to set the other to be in the range of 52-95%.

As a result, the soundproofing material 10 of the present invention has a synergistic and well-balanced sound absorption mechanism, and has a high level of sound absorption coefficient that is effective in actual use even if the total thickness of the soundproofing material 10 is thin. Furthermore, it is presumed that the effect of expanding the frequency band capable of absorbing sound was achieved.

In the soundproof material 10 of the present invention, one of the bonding area ratio S1 of the first bonding layer 12 and the bonding area ratio S2 of the second bonding layer 14 is 5 to 95%. and the other bonding area ratio is in the range of 52 to 95%, preferably in the range of 80 to 95%.

That is, (1) when the bonding area ratio S1 is in the range of 5 to 95%, the other bonding area ratio S2 is in the range of 52 to 95%, preferably in the range of 80 to 95%. Here, if the joint area ratio S1 is less than 5%, the sound absorption coefficient of the soundproof material in the frequency band of less than 2000 Hz may decrease. There is a risk that the sound absorption coefficient in the frequency band of In addition, if the joint area ratio S2 is less than 52%, the sound absorption coefficient of the soundproof material in the frequency band of less than 2000 Hz may decrease. There is a risk that the sound absorption coefficient of the frequency band will decrease.

Conversely, when (2) the bonding area ratio S2 is in the range of 5 to 95%, the other bonding area ratio S1 is in the range of 52 to 95%, preferably in the range of 80 to 95%. Here, if the joint area ratio S2 is less than 5%, the sound absorption coefficient of the soundproof material in the frequency band of less than 2000 Hz may decrease. There is a risk that the sound absorption coefficient in the frequency band of Also, if the joint area ratio S1 is less than 52%, the sound absorption coefficient of the soundproof material in the frequency band of less than 2000 Hz may decrease. There is a risk that the sound absorption coefficient of the frequency band will decrease.

In the soundproof material 10 of the present invention, one of the bonding area ratio S1 of the first bonding layer 12 and the bonding area ratio S2 of the second bonding layer 14 is 5 to 95%. In the other range where the joint area ratio is 52 to 95%, by increasing the joint area ratio, even if the total thickness of the soundproofing material 10 is constant, the frequency of the sound absorption peak is shifted in the low frequency direction. It may be possible to shift to

The shapes of the first bonding layer 12 and the second bonding layer 14 are either the bonding area ratio S1 of the first bonding layer 12 or the bonding area ratio S2 of the second bonding layer 14. The area ratio is in the range of 5 to 95% with respect to the entire contact surface between the intermediate layer 13 and the first sound absorbing layer 11 and the intermediate layer 13 and the second sound absorbing layer 15, and the other bonding area ratio is 52 to 52%. 95% range, that is, the total opening ratio of one of the breathable openings 16 and 17 is in the range of 5 to 95%, and the other opening There is no particular limitation as long as the air-permeable openings 16 and 17 are formed in a part of the contact surface so that the total opening ratio of is in the range of 5 to 48%. 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. It is preferable that a plurality of air-permeable openings 16 and 17 are uniformly 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 one preferred embodiment, the first bonding layer 12 and the second bonding layer 14 (not shown) are, for example, a plurality of rod-shaped layers. A bar-shaped layer refers to a linear layer having a predetermined width. When the rod-shaped bonding layers are uniformly formed 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 16 and 17 (not shown) are formed between two adjacent bar-shaped layers on the contact surface.

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 set so as to have at least a plurality of openings 16 and 17, and preferably 14 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 16 and 17, for example, 6 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 and the second bonding layer 14 are not particularly limited as long as the effects of the present invention are not hindered, but are in the range of 0.025 to 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, 2, the bonding strength with the 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 in the high frequency band may decrease if the bonding area is large, and the thickness and weight of the soundproof material 10 will increase, resulting in a reduction in thickness and weight. not suitable for In addition, the density of the first bonding layer 12 and the second bonding layer 14 is not particularly limited as long as the effect of the present invention is not hindered. It is preferably in the range of ~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 a 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 has the bonding area ratio S1 of the first bonding layer 12 and the bonding area ratio S1 of the second bonding layer 14 without changing the total thickness of the soundproofing material 10. By controlling the bonding area ratio of one of S2 in the range of 5 to 95% and the bonding area ratio of the other in the range of 52 to 95%, it is possible to expand the effective sound absorbing frequency band as a sound absorbing material. Therefore, it is possible to provide an effective means for solving the above problems. By using a specific intermediate layer 13, which will be described later, even if the total thickness of the soundproofing material 10 is made thinner than that of the conventional product, the sound absorbing frequency range effective as the soundproofing 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, this phenomenon can also be covered by the properties of the intermediate layer 13, and as a result, even if the soundproofing material 10 of the present invention is thin, the sound absorbing frequency range is expanded in actual use. It can be effective.

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 2-9 μm, and more preferably in the range of 2-6 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 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 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 air permeability of the intermediate layer 13 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 intermediate layer 13 exceeds 200 cm ³ /cm ² ·sec, the sound absorption coefficient in the frequency band below 2000 Hz (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 in which voids are communicated. 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, the light incident on the second sound absorbing layer 15 In addition to the sound waves that pass through the second sound absorbing layer 15 and the intermediate layer 13 without being absorbed, the sound waves are efficiently transmitted to the fiber material or the open-cell foam material of the first sound absorbing layer 11, and the sound waves A part of the energy can be exchanged for heat energy and consumed by 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 as described above, not only the sound waves incident on the second sound absorbing layer 15 but also the second sound absorbing layer 15 Also, the sound wave transmitted through the intermediate layer 13 without being absorbed is efficiently transmitted to the fiber material or the foam material having open cells of the first sound absorbing layer 11, and part of the energy of the sound wave is transferred to the peripheral wall of the skeleton portion. Friction, viscous resistance, and even bone vibrations can be used to convert and consume heat energy.

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 .

<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. obtained by joining with As a method for bonding the intermediate layer 13 and the first sound absorbing layer 11, and the intermediate layer 13 and the second sound absorbing layer 15, as described above, each layer is bonded with a coated adhesive or double-sided adhesive tape (base material). A preferred method is to use a double-sided adhesive tape that does not require a material) to bond them together so that a predetermined bonding area ratio is obtained. 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 release film coated with an adhesive in stripes or dots or the like is pasted or transferred so as to have a predetermined bonding area ratio, and then both layers are crimped.・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, in the same manner, the second sound absorbing layer 15 is attached 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 by the second bonding layer 14, and a predetermined bonding is performed. After pasting or transferring so as to obtain the area ratio, both layers are press-bonded and joined.

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 center frequencies of 1600, 2000, 2500, 3150 and 4000 Hz in the 1/3 octave band. is preferable, and more preferably 55% or more at all of 1/3 octave band center frequencies of 1250, 1600, 2000, 2500, 3150 and 4000 Hz, and 1/3 octave band center frequencies of 1000, 1250, 1600 and 2000 , 2500, 3150, and 4000 Hz are particularly preferably 55% or more.

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, by setting the thickness of the soundproof material and the joint area ratio in each of the joint layers between the intermediate layer and the first sound absorbing layer, and between the intermediate layer and the second sound absorbing layer, which constitute the soundproof material, within the above ranges. Thus, it is possible to obtain a soundproofing material which is excellent in winding workability, cutting workability, and handleability during stacking, transportation, etc., while ensuring a wide range of sound-absorbable frequency ranges.

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) 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, the frequency range of 1/3 octave band center frequency 1000 to 4000 Hz. We measured the normal incidence sound absorption coefficient at 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 arbitrarily 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 intermediate layer and sound absorbing layer Measured according to JIS-L-1913-B method. The load was 20 kPa for the intermediate layer and 0.02 kPa for the sound absorbing layer.

(5) Fabric weight of intermediate layer and sound absorbing 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. prepared. 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.

(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 so as to face each other, and the sound insulating material was obtained by bonding the two layers by pressing under a normal temperature environment. This soundproof material was cut into a circular shape with a diameter of 28.8 mm, and the sound absorption coefficient was measured.

The total thickness of the obtained soundproof material was 21.1 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 9%, and the bonding area ratio of the second bonding layer was 52%.

<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 obtained soundproof material was 21.1 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 9%, and the bonding area ratio of the second bonding layer was 95%.

<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 obtained soundproof material was 21.1 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 22%, and the bonding area ratio of the second bonding layer was 52%.

<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 obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 22%, and the bonding area ratio of the second bonding layer was 81%.

<Example 5>
A soundproof material was obtained in the same manner as in Example 2, except that the formation of the first bonding layer was 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 obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 22%, and the bonding area ratio of the second bonding layer was 95%.

<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 bar-shaped adhesive tape is applied to the surface of the felt in the following manner: line (adhesive tape junction)/space (opening)/line/space/line=2.6 mm/23.6 mm/2. They were arranged and bonded in parallel so as to have a thickness of 6 mm to form a second bonding layer (with a separator).

The total thickness of the obtained soundproof material was 21.1 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. %Met

<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 obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 52%, and the bonding area ratio of the second bonding layer was 22%.

<Example 8>
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 bars with widths of 6 mm and 5 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 obtained soundproof material was 21.1 mm. In the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 52%, and the bonding area ratio of the second bonding layer was 52%.

<Example 9>
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. 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.

The total thickness of the obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 22%.

<Example 10>
A soundproof material was obtained in the same manner as in Example 9, 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, 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 obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 43%.

<Example 11>
A soundproof material was obtained in the same manner as in Example 10, 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 (with separator) was formed.

The total thickness of the obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 81%.

<Example 12>
A soundproof material was obtained in the same manner as in Example 2, except that the formation of the first bonding layer was 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 obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 95%, and the bonding area ratio of the second bonding layer was 95%.

<Example 13>
A soundproof material was obtained in the same manner as in Example 12, 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 obtained soundproof material was 21.1 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 95%, and the bonding area ratio of the second bonding layer was 9%.

<Example 14>
A soundproof material was obtained in the same manner as in Example 3, except that the following intermediate layer was used.

(middle layer)
As an intermediate 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. prepared the material. 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 obtained soundproof material was 25.0 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%, and the bonding area ratio of the second bonding layer was 52%.

<Example 15>
A soundproof material was obtained in the same manner as in Example 7, except that the following intermediate layer was used.

(middle layer)
As an intermediate 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. prepared the material. 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 obtained soundproof material was 25.0 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 52%, and the bonding area ratio of the second bonding layer was 22%.

<Example 16>
A soundproof material was obtained in the same manner as in Example 10, except that the following intermediate layer was used.

(middle layer)
As an intermediate 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. prepared the material. 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 obtained soundproof material was 25.0 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 43%.

<Example 17>
As a bonding material for the first bonding layer and the second bonding layer, a baseless double-sided adhesive tape "KF4#100" manufactured by New Tac Kasei Co., Ltd. using an acrylic adhesive (trade name, base material: none, adhesive tape A soundproof material was obtained in the same manner as in Example 9, except that the thickness was 0.1 mm, both sides had separators, and the storage elastic modulus of the adhesive was 1.1×10 ⁵ Pa).

The total thickness of the obtained soundproof material was 20.3 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 22%.

<Example 18>
As a bonding material for the first bonding layer and the second bonding layer, an acrylic pressure-sensitive adhesive (2-methoxyethyl acrylate/2-ethylhexyl acrylate/4-hydroxybutyl acrylate/hexamethylene diisocyanate-based cross-linking agent = 40 parts by mass/59 Baseless double-sided adhesive tape (base material: none, adhesive tape thickness: 0.1 mm, with separator on both sides, storage elastic modulus of adhesive: 6.5 parts by mass/1 part by mass/0.7 parts by mass) A soundproof material was obtained in the same manner as in Example 9, except that 0×10 ⁴ Pa) was used.

The total thickness of the obtained soundproof material was 20.3 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 22%.

<Example 19>
As a bonding material for the first bonding layer and the second bonding layer, a double-sided adhesive tape manufactured by Maxell using a butyl rubber-based adhesive "No. A soundproof material was obtained in the same manner as in Example 9, except that thickness: 3.0 mm, single-sided separator, storage elastic modulus of adhesive: 3.6 × 10 ⁵ Pa) was used.

The total thickness of the obtained soundproof material was 26.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 22%.

<Example 20>
A soundproof material was obtained in the same manner as in Example 9, except that the following intermediate layer was used.

(middle layer)
As an intermediate layer, an acrylic/polyester having 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 A mixed fibrous material was prepared. 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 21.5 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 22%.

<Example 21>
A soundproof material was obtained in the same manner as in Example 9, except that the following intermediate layer was used.

(middle layer)
A polyester fiber material having 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 was prepared. This polyester fiber material has a random arrangement of fibers.

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 of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 22%.

<Example 22>
A soundproof material was obtained in the same manner as in Example 9, except that the first sound absorbing layer and the second sound absorbing layer were as follows.

(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 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.

The total thickness of the resulting soundproof material was 11.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 22%.

<Example 23>
A soundproof material was obtained in the same manner as in Example 9, except that the first sound absorbing layer and the second sound absorbing layer were as follows.

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.

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 of the adhesive tape was 81%, and the bonding area ratio of the second bonding layer was 22%.

<Example 24>
A soundproof material was obtained in the same manner as in Example 9, except that the intermediate layer and the second bonding layer were formed as follows.

(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. prepared.

(Formation of bonding layer)
Double-sided adhesive tape "No.5933 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 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 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%, and the bonding area ratio of the second bonding layer was 52%.

<Comparative Example 1>
A soundproof material was obtained in the same manner as in Example 1, except that the intermediate layer was not joined with a joining layer and the second sound absorbing layer was not used. That is, a soundproof material having only the first sound absorbing layer with a thickness of 10 mm was obtained.

<Comparative Example 2>
A soundproof material was obtained in the same manner as in Example 1, except that the intermediate layer was not joined with a joining layer, the second sound absorbing layer was not used, and the following first sound absorbing layer was used. That is, a soundproof material having only the first sound absorbing layer with a thickness of 20 mm was obtained.
(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 Prepared the felt.

<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 Comparative Example 1 was simply superimposed without being joined with an adhesive tape. and The total thickness of the soundproof material was 30 mm.

<Comparative Example 4>
A soundproof material was obtained in the same manner as in Example 1, except that the formation and bonding of the first bonding layer and the second 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. A soundproof material was obtained by

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 so as to face each other, and the sound insulating material was obtained by bonding the two layers by pressing under a normal temperature environment.

The total thickness of the obtained soundproof material was 21.1 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 100%, and the bonding area ratio of the second bonding layer was 100%.

<Comparative Example 5>
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. 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).

The total thickness of the obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 43%, and the bonding area ratio of the second bonding layer was 22%.

<Comparative Example 6>
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. 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 obtained soundproof material was 21.1 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%, and the bonding area ratio of the second bonding layer was 22%.

<Comparative Example 7>
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 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.

The total thickness of the obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 9%, and the bonding area ratio of the second bonding layer was 9%.

<Comparative Example 8>
The first sound absorbing layer, the intermediate layer, and the second sound absorbing layer used in Example 1 were simply layered together without bonding with an adhesive tape to form a soundproof material. The total thickness of the soundproof material was 20.1 mm.

<Comparative Example 9>
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 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 obtained soundproof material was 21.1 mm. In addition, in the sound absorption coefficient measurement sample of Φ28.8 mm, the bonding area ratio of the first bonding layer formed of the adhesive tape was 22%, and the bonding area ratio of the second bonding layer was 100%.

<Comparative Example 10>
A soundproof material was obtained in the same manner as in Comparative Example 6, except that the intermediate layer was as follows.

(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. prepared.

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%, and the bonding area ratio of the second bonding layer was 22%.

<Comparative Example 11>
A soundproof material was obtained in the same manner as in Example 24, 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 obtained soundproof material was 23.0 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%, and the bonding area ratio of the second bonding layer was 52%.

<Comparative Example 12>
A soundproof material was obtained in the same manner as in Example 24, 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 obtained soundproof material was 21.1 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%, and the bonding area ratio of the second bonding layer was 52%.

Tables 1 to 5 show the structure and measurement results of normal incidence sound absorption coefficients for each of the soundproof materials of Examples 1 to 24 and Comparative Examples 1 to 12.

As is clear from Tables 1 to 5, all the soundproof materials of Examples 1 to 24 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 1600, 2000, 2500, 3150 and 4000 Hz. It can be seen that in Examples 16, 17, 19, 20 and 23, the effective sound absorbing frequency band as a sound absorbing material is also expanded.

The examples are compared in detail below. In Examples 1 and 2 in which the bonding area ratio of the first bonding layer is the same as 9%, in Example 2 in which the bonding area ratio of the second bonding layer is 95%, the bonding area of the second bonding layer Compared to Example 1 where the coefficient of sound absorption is 52%, although the normal incidence sound absorption coefficient in the high frequency band is slightly lower, the sound absorption frequency band effective as a sound absorbing material (frequency band where the normal incidence sound absorption coefficient is 55% or more) It can be seen that it has expanded further.

Further, in Examples 3 to 5 in which the bonding area ratio of the first bonding layer is the same as 22%, Examples 4 and 5 in which the bonding area ratio of the second bonding layer is 81% and 95%, respectively Compared to Example 3 in which the bonding area ratio of the second bonding layer is 52%, although the normal incidence sound absorption coefficient in the high frequency band is slightly lower, the sound absorption frequency band effective as a sound absorbing material (vertical incidence sound absorption It can be seen that the frequency band in which the rate is 55% or more has expanded more.

Further, in Examples 6 and 13 in which the bonding area ratio of the second bonding layer is the same as 9%, Example 13 in which the bonding area ratio of the first bonding layer is 95% is the same as that of the second bonding layer. Compared with Example 6 in which the joint area ratio is 52%, the normal incidence sound absorption coefficient in the high frequency band is slightly lower, but the sound absorption frequency band effective as a sound absorbing material (the frequency band where the normal incidence sound absorption coefficient is 55% or more ) is expanded more.

Further, in Examples 7 and 9 in which the second bonding layer has the same bonding area ratio of 22%, Example 9 in which the first bonding layer has a bonding area ratio of 81% has the second bonding layer Compared to Example 7 in which the joint area ratio is 52%, the normal incidence sound absorption coefficient in the high frequency band is slightly lower, but the sound absorption frequency band effective as a sound absorbing material (the frequency band where the normal incidence sound absorption coefficient is 55% or more ) is expanded more.

Furthermore, in Examples 9, 20, and 21 in which the first bonding layer had a bonding area ratio of 81% and the second bonding layer had a bonding area ratio of 22%, the intermediate layer had an air permeability of 21 cm ³ / cm ² ·sec, compared to Example 20 where the intermediate layer air permeability is 9 cm ³ /cm ² ·sec, the normal incident sound absorption coefficient is relatively high, and the intermediate layer air permeability is Compared to Example 21, which is 190 cm ³ /cm ² ·sec, the normal incidence sound absorption coefficient in the high frequency band is slightly lower, but the sound absorption frequency band effective as a sound absorbing material (frequency at which the normal incidence sound absorption coefficient is 55% or more It can be seen that the bandwidth) is more expanded.

Furthermore, in Examples 9, 22, and 23 in which the bonding area ratio of the first bonding layer is 81% and the bonding area ratio of the second bonding layer is 22%, the first and second sound absorbing layers Example 9, in which the basis weight is 200 g/ ^m2 , has a relatively high normal incidence sound absorption coefficient compared to Example 22, in which the basis weight of the first sound absorbing layer and the second sound absorbing layer is 100 g/ ^m2. , the sound absorbing frequency band effective as a sound absorbing material (the frequency band in which the normal incidence sound absorption coefficient is 55% or more) is also expanded. Similarly, in Example 23 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 , 100 g/m ² , Compared to Examples 9 and 22, the normal incidence sound absorption coefficient is relatively high, and the sound absorption frequency band effective as a sound absorbing material (frequency band in which the normal incidence sound absorption coefficient is 55% or more) is also expanded. I understand.

Furthermore, Example 9 and Examples 17 to 19 with the same bonding area ratio of 81% for the first bonding layer and 22% for the bonding area ratio of the second bonding layer, but with different types and thicknesses of bonding materials. , Examples 17 to 19 all exhibit good sound absorption characteristics as in Example 9, and in particular, Example 19, in which the thickness of the bonding material is 3 mm, compares favorably with Examples 9, 17, and 18. By comparison, it can be seen that the normal incidence sound absorption coefficient is high in the sound absorption frequency band of 2000 Hz or less (the frequency band in which the normal incidence sound absorption coefficient is 55% or more).

Furthermore, Example 24, in which the average fiber diameter of the fibrous material of the intermediate layer is 17 μm, is compared with Examples 10 and 16, in which the average fiber diameter of the fibrous material of the intermediate layer is 3 μm and 10 μm, respectively, which have similar bonding area ratios. As a result, in the sound absorption frequency band of 2000 Hz or less, the normal incident sound absorption coefficient is slightly low, and the sound absorption frequency band effective as a sound absorbing material (frequency band in which the normal incidence sound absorption coefficient is 55% or more) is also somewhat narrow.

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 24. 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.

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, 20 soundproof material 11 first sound absorbing layer 12 first bonding layer 13 intermediate layer 14 second bonding layer 15 second sound absorbing layer 16, 17 ventilation openings

Claims (14)

having a first sound absorbing layer, a first bonding layer, an intermediate layer, a second bonding layer, and a second sound absorbing layer laminated in order;
The first sound absorbing layer and the second sound absorbing layer are each independently made of a porous material with interconnecting voids,
The intermediate layer is 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 fibrous material of the intermediate layer is a thermoplastic synthetic fiber,
The porous material formed by communicating the voids of the first sound absorbing layer and the second sound absorbing layer is a fiber material having a basis weight of 100 to 300 g/m ² ,
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 When the bonding area ratio to the whole is S2, the bonding area ratio of either S1 or S2 is in the range of 5 to 95%, and the bonding area ratio of the other is 52 to 95%. A range of soundproofing materials. The soundproofing according to claim 1, wherein the joint area ratio of one of the S1 and the S2 is in the range of 5 to 95%, and the joint area ratio of the other is in the range of 80 to 95%. material. The soundproof material according to claim 1 or 2, wherein the bonding material used for the first bonding layer and the second bonding layer is a coated adhesive or double-sided adhesive tape. 4. The soundproof material according to claim 3, 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 claim 1, wherein the first joint layer and the second joint layer are formed from a plurality of rod-shaped layers. The soundproof material according to claim 5, wherein the plurality of bar-shaped layers form a striped pattern. 7. The soundproof material according to claim 6, wherein the distance between adjacent bar-shaped layers is 1 mm or more. The soundproof material according to any one of claims 1 to 7, wherein the intermediate layer has an air permeability of 10 to 100 ^cm3 /cm2 ^· sec. The soundproof material according to any one of claims 1 to 8 , 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 1600, 2000, 2500, 3150 and 4000 Hz in the 1/3 octave band. 10. The soundproof material according to any one of 9 . 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. 10. The soundproof material according to any one of 1 to 9 . 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 1-9 . The soundproofing material according to any one of claims 1 to 12, wherein the thermoplastic synthetic fibers comprise polyester fibers. The soundproof material according to any one of claims 1 to 13, wherein the first bonding layer and the second bonding layer have a thickness of 0.025 to 3 mm.

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