JPH10203268A - Sound insulation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make high sound absorption and low springing compatible by making thickness of an internal surface layer which is super extra fine fiber unwoven cloth and is located on the opposite side to a sound incident plane specified times as much as that of a surface layer. SOLUTION: In a sound insulation structure, unwoven cloth constituting a surface layer and a back face layer is made of polypropylene extra superfine fiber which can be obtained by a melt blow process. The surface layer and the back face layer are made of unwoven cloth made of extra superfine fibers of fiber diameter 0.1 to 10μm which can be obtained by the melt blow process. The average apparent density of the surface layer and the back face layer is determined for a range of 0.03 to 0.06g/cm<3> . Further, thicknesses of the surface layer and the back face layer are determined for a range of 5 to 15mm. Thickness of the internal layer is made 2 to 5 times as much as that of the surface layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-performance sound insulation structure for a vehicle, and more particularly to a sound insulation structure for a vehicle having both high sound absorption performance and high sound insulation performance.
It is suitably used as an interior sound absorbing and insulating material for automobiles, such as an automobile sound absorbing and insulating material, a floor insulator, and an automobile dash insulator attached to a dash panel.

[0002]

2. Description of the Related Art In recent years, interior materials for automobiles, particularly floor insulators and dash insulators, have been required to have good sound insulation performance and sound absorption performance. Conventionally, felt and urethane foams have been used as such sound insulation structures for automobiles. Was often done. However, since felt has poor adhesion to a panel due to poor shapeability, it generally has poor sound absorbing and insulating performance. In addition, when used for floor insulators and the like, irregularities due to the laid wire harness and the like may not be absorbed, and irregularities may be generated on the carpet skin, resulting in poor appearance. Furthermore, since the defibrated fibers contain natural fibers, they lack quality stability. In addition, there is a drawback that the sagging over time occurs due to weak bonding between the fibers.

[0003] On the other hand, when urethane foam is used as a sound insulation structure, a bonding step between the carpet skin and the urethane foam is required, resulting in high costs. A method has been developed in which a carpet skin and a urethane foaming raw material are charged into a foaming mold and molded integrally, but productivity is inferior because resin injection and foaming and fixing processes are required, and the equipment becomes large-scale. In addition, since the raw material of the urethane foam is used, the working environment is poor, and exhaust equipment is required. Furthermore, urethane foam is difficult to recycle and is not preferred because it poses an environmental problem, and is inferior in sound insulation performance because it is harder than felt.

In order to improve such disadvantages, Japanese Patent Application Laid-Open No.
JP-A-223357, JP-A-4-272263 and JP-A-4-185754 disclose a sound insulating structure using a synthetic fiber nonwoven fabric such as polyester. By the way, the thermal bond type synthetic fiber non-woven fabric using the heat fusion fiber (binder fiber) is obtained by changing the amount of the binder fiber, the fiber diameter, and the apparent density.
It is possible to control the spring constant and sound absorption performance. That is, the resonance point can be tuned, and good sound insulation performance can be obtained by shifting the resonance point of the sound insulation structure from the frequency at which the noise input is large.

However, when the frequency of a large noise input is over a wide range, the sound insulation is not sufficient only by tuning the resonance point, and a high damping of the sound insulation structure is required. However, it is difficult to achieve high damping with a conventional sound insulating structure using felt, urethane foam, or synthetic fiber nonwoven fabric, and at present it is difficult to control the damping. For this reason, a sound insulation structure has been devised in which the sound insulation structure has a multi-layer structure and one layer of the structure is made of an ultra-fine fiber non-woven fabric obtained by a melt blow method (Japanese Patent Application No. 7-151549).

[0006]

By using the above-mentioned multilayer sound insulation structure, the damping performance is excellent and the damping characteristics can be controlled. However, in this multilayer sound insulating structure, since the ultrafine fiber layer is located on the opposite side or the middle of the main sound incident surface, high sound absorption, which is a great feature of the ultrafine fiber nonwoven fabric, cannot be exhibited. In addition, the ultra-fine fiber nonwoven fabric has a very large dynamic spring constant from the beginning, and if the thickness of other layers is not sufficiently ensured with respect to the ultra-fine fiber layer, the spring constant increases and the sound insulation performance decreases. was there. Further, the performance of the sound absorbing and insulating structure is mainly determined by the sound absorbing performance and the spring characteristics. However, these two performances have a trade-off aspect, and it is difficult to achieve both high sound absorbing performance and low spring.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to maintain a high sound absorbing property, which is a great feature of a microfiber nonwoven fabric, while maintaining a high sound absorbing property. An object of the present invention is to provide a sound insulating structure for an automobile having both high sound absorbing properties and high sound insulating properties (lower spring) by suppressing the constant to be low.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the high sound absorption performance of the ultrafine fiber non-woven fabric as described above has two characteristics, a membrane resonance sound absorption form and a porous structure sound absorption form. It was found that the difference was due to the mixing of various types of sound absorbing forms, and that the dynamic spring constant of the microfiber nonwoven fabric was mostly occupied by air springs. Therefore, the sound insulation structure was multi-layered and the ultra-fine fiber non-woven fabric was placed on the surface layer that would be the main sound incident surface, and the thickness and density of the surface layer and the thickness and density of the inner layer located on the opposite side were specified. The inventors have found that the above problems can be solved, and have completed the present invention.

That is, the sound insulation structure for automobiles of the present invention is a laminated structure composed of two or more fiber aggregates having different fiber compositions, and a surface layer serving as a main sound incidence surface is obtained by a melt blow method. Average apparent density of fibers having a fiber diameter of 0.1 to 10 μm 0.03 to 0.06 g / c
m ³ , a polypropylene nonwoven fabric having a thickness of 5 to 15 mm, wherein the thickness of the inner surface layer located on the opposite side to the sound incidence surface is 2 to 5 times the surface layer.

[0010]

As described above, the present inventors have determined that the high sound absorption performance of the polypropylene ultrafine fiber nonwoven fabric is due to the admixture of two types of sound absorption forms, a membrane resonance sound absorption form and a porous structure sound absorption form. It has been clarified that the air spring occupies most of the dynamic spring constant of the polypropylene microfiber nonwoven fabric.

That is, the polypropylene ultra-fine fiber non-woven fabric has a smaller fiber diameter than the conventional synthetic fiber non-woven fabric, and therefore has a very large fiber surface area and a large friction with flowing air. For this reason, the polypropylene ultra-fine fiber non-woven fabric has an extremely high airflow resistance, and a part of the surface layer of the non-woven fabric acts as a membrane, causing sound absorption due to membrane resonance. The high sound absorption performance near 500 Hz that is not seen in the conventional synthetic fiber nonwoven fabric is mainly due to this.

In the present invention, the sound absorption structure is caused by membrane resonance by disposing the ultra-fine polypropylene fiber non-woven fabric on the surface layer serving as the main sound incident surface of the multilayered sound insulation structure, and the polypropylene ultra-fine fiber non-woven fabric is provided. It is possible to obtain the same high sound absorbing performance as that of a single device. Also, if the sound insulation structure is a three-layer structure consisting of a surface layer, an inner layer, and a back layer in order from the main sound incident direction, and if the surface layer and the back layer are made of polypropylene ultra-fine fiber non-woven fabric, if only the main sound source is used In addition, high sound absorption performance can be provided for reflected sound and the like.

By the way, the dynamic spring constant is composed of a fiber spring and an air spring. However, the air permeability of the polypropylene ultrafine fiber nonwoven fabric is several times to tens of times larger than that of the fiber spring because of its high airflow resistance. The dynamic spring constant is very large and the sound insulation performance is low when polypropylene ultra-fine fiber nonwoven fabric is used alone. Thus, in the present invention, the air spring of the entire sound insulation structure is reduced by laminating with a nonwoven fabric made of a polyester fiber having a small airflow resistance having a thickness of 2 to 5 times the thickness of the polypropylene ultrafine fiber nonwoven fabric. Greatly reduces the dynamic spring constant.

From the above findings, in the present invention, the sound insulating structure is multi-layered, and a polypropylene ultra-fine fiber nonwoven fabric is disposed on a surface layer serving as a main sound incident surface, and the non-woven fabric is provided on the opposite side to the sound incident surface. In the inner layer located, 2 to the surface layer
By providing the thickness five times, it is possible to achieve both excellent sound absorbing performance and sound insulating performance.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a sound insulation structure for an automobile according to the present invention will be described in detail. As described above, the multilayer sound insulating structure of the present invention includes a surface layer and an inner layer, but the main sound incident surface is a surface layer, and the surface located on the opposite side to the sound incident surface is an inner layer. Name. In the case of a three-layer structure, they are referred to as a surface layer, an inner layer, and a back layer in order from the main sound incident direction. 1 and 2 schematically show the configuration of the sound insulation structure of the present invention.

In the sound insulation structure of the present invention, the nonwoven fabric constituting the surface layer and the back layer is made of ultrafine fibers obtained by a melt blow method. As a material of the fiber, polypropylene is preferable from the viewpoint of cost and ease of production. The nonwoven fabric forming the inner layer is preferably made of polyester fiber in view of cost, moldability, durability, performance stability after processing, and the like.

Further, it is necessary that the surface layer and the back layer are formed of a non-woven fabric made of ultra-fine fibers having a fiber diameter of 0.1 to 10 μm obtained by a melt blow method. This is because it is difficult to obtain fibers having a fiber diameter of less than 0.1 μm, and it is difficult to obtain rigidity as a cushioning material. On the other hand, if the fiber diameter exceeds 10 μm, it is not possible to obtain a sufficient airflow resistance to cause membrane sound absorption. This is because the sound absorbing performance may be deteriorated.

The average apparent density of the surface layer and the back layer is
It needs to be in the range of 0.03 to 0.06 g / cm ³ . When the average apparent density is less than 0.03 g / cm ³ , when used as a floor insulator, the cushioning property is extremely reduced, and even when the inner surface layer is hardened, sinking under load may occur. 0.06 g / cm ³
If the ratio exceeds the above range, the sound insulation performance, the riding comfort, etc. may be reduced, and the followability during molding may be deteriorated.

Further, the thickness of the surface layer and the back layer is 5 to 1
It needs to be in the range of 5 mm. If the thickness is less than 5 mm, the effect of the ultrafine fibrous nonwoven fabric is small, and high sound absorbing performance may not be obtained. On the other hand, when the thickness exceeds 15 mm, the thickness of the entire laminate becomes too thick, which may cause a problem in installation.

On the other hand, the thickness of the inner surface layer is two times the thickness of the surface layer.
It is necessary to make it up to 5 times. In the case of a three-layer structure, the thickness of the inner surface layer is preferably 2 to 5 times the thickness of the thicker one of the surface layer and the back layer. If it is less than twice, the air spring of the ultrafine fiber nonwoven fabric cannot be greatly reduced, and the dynamic spring becomes large, resulting in poor sound insulation.
On the other hand, if it exceeds 5 times, the thickness of the entire laminate becomes too large, which may cause a problem in installation.

The nonwoven fabric constituting the inner surface layer is 1 to 50
It is preferable that the fiber has a fiber diameter in the range of denier and has an average apparent density of 0.01 to 0.07 g.
/ Cm ³ is preferable. If the fiber diameter is less than 1 denier, it is difficult to obtain an appropriate cushioning property, and the durability may be reduced. Further, there is a possibility that the yarn protection speed is significantly reduced, the card passing property is poor, and the quality of the nonwoven fabric is deteriorated. On the other hand, if it exceeds 50 denier, the nonwoven fabric becomes too hard, the dynamic spring constant increases, and the sound insulation may decrease. The average apparent density is 0.01 g / cm ³
If it is less than 1.0, the cushioning property and the durability are significantly reduced,
When it exceeds 07 g / cm ³ , the air spring of the inner surface layer becomes large and the air spring of the ultrafine fiber non-woven fabric cannot be reduced, so that the sound insulation property is inferior and the demand for weight reduction is defeated.

In the present invention, the nonwoven fabric constituting the inner surface layer is composed of at least two kinds of polyester fibers, 60 to 95% by weight of the fiber 1 is polyethylene terephthalate fiber, and 5 to 40% by weight of the fiber 2 is It is preferable to use a polyester fiber having a core-in-sheath structure, which is a copolymerized polyester whose melting point of the sheath is 100 ° C. or lower than that of the fiber 1. Here, the reason why the fiber 1 is made of polyethylene terephthalate fiber is to secure a difference in melting point from the binder fiber and widen the melting point range of the binder fiber that can be selected.

The fibers 2 function as binder fibers. The reason why the melting point of the sheath portion of the fiber 2 is lower than that of the fiber 1 by 100 ° C. or more is that if the difference in melting point is less than 100 ° C., the melting point of the ultrafine polypropylene fibers constituting the surface layer and the back layer overlaps. This is because the temperature conditions during molding become severe. In some cases, the ultrafine fibers may melt and the desired performance may not be obtained. The melting point difference is not particularly limited because it does not cause a problem even if it is too large. However, at 150 ° C. or more, the melting point of the fiber 2 is too low, and handling becomes difficult. The material of the core portion of the fiber 2 is not particularly limited, but is preferably polyethylene terephthalate in order to easily function as a binder fiber.

Fiber 1 is 60 to 95% by weight and fiber 2 is 5 to 5% by weight.
The reason for setting it to 40% by weight is as follows. That is, fiber 1
Is less than 60% by weight and the fiber 2 exceeds 40% by weight, the amount of the binder fiber is too large, which may lead to an increase in cost and a deterioration in cushioning property. When the content of the fiber 1 is more than 95% by weight and the content of the fiber 2 is less than 5% by weight, the amount of the binder fiber is too small, and the moldability and durability may be reduced.

The thickness of the entire laminated structure is preferably about 20 to 50 mm so as to maintain good sound absorption and sound insulation performance and not cause a problem in installation. Further, the sound insulation structure of the present invention can be suitably used as a dash insulator or a floor insulator of an automobile or the like.

[0026]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, Comparative Examples and Conventional Examples, but the present invention is not limited to these Examples. (Example 1) Average fiber diameter 3 μm, thickness 8 mm, average apparent density 0.05 g / c obtained by a melt blow method
The polypropylene microfiber nonwoven m ³ in the surface layer,
6-denier polyester fiber with fiber blend of 51 mm x 8
0%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 20%, 20 mm thick, average apparent density of 0.05 g / cm ³ non-woven fabric made of polyester for the inner surface layer, and laminated. To produce a sound insulation structure for automobiles.

(Example 2) An ultrafine nonwoven fabric made of polypropylene having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt blow method was used as a surface layer, and a fiber blend of 2 denier × 51 mm was used. Polyester fiber: 80%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 20% thick, 20 mm thick, non-woven fabric made of polyester having an average apparent density of 0.04 g / cm ³ is used for the inner surface layer. And laminated to form a sound insulating structure for an automobile.

Example 3 A polypropylene ultra-fine fiber nonwoven fabric having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt-blowing method was used as a surface layer, and a fiber blend of 2 denier × 51 mm was used. Polyester fiber: 80%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 20% thick, 20 mm thick, non-woven fabric made of polyester having an average apparent density of 0.06 g / cm ³ is used for the inner surface layer. And laminated to form a sound insulating structure for an automobile.

Example 4 A nonwoven fabric made of ultrafine polypropylene fibers having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt-blowing method was used as a surface layer. Polyester fiber: 80%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 20%, thickness: 30 mm, polyester nonwoven fabric having an average apparent density of 0.05 g / cm ³ is used for the inner surface layer. And laminated to form a sound insulating structure for an automobile.

(Example 5) An ultrafine nonwoven fabric made of polypropylene having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.04 g / cm ³ obtained by a melt-blowing method was used as a surface layer, and a fiber blend of 2 denier × 51 mm was used. Polyester fiber: 80%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 20%, 25 mm thick, non-woven fabric made of polyester having an average apparent density of 0.06 g / cm ³ is used for the inner surface layer. And laminated to form a sound insulating structure for an automobile.

Example 6 A nonwoven fabric made of polypropylene ultrafine fibers having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt-blowing method was used as a surface layer, and 6 denier × 51 mm of a fiber blend was used. Polyester fiber: 90%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 10%, 20 mm thick, polyester nonwoven fabric having an average apparent density of 0.05 g / cm ³ is used for the inner surface layer. And laminated to form a sound insulating structure for an automobile.

(Example 7) A polypropylene ultra-fine fiber nonwoven fabric having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt blow method was used for the surface layer and the back layer, and the fiber blending was 6 denier. × 51m
m polyester fiber: 80%, 2 denier x 51 mm
Core-sheath type binder fiber (sheath melting point 110 ° C):
20% thickness 20mm, average apparent density 0.05g / c
using polyester nonwoven fabric of m ³ on the inner surface layer, creating the automotive sound insulation structure by laminating.

(Example 8) A polypropylene ultra-fine fiber nonwoven fabric having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt-blowing method was used for the surface layer and the back layer, and 2 deniers of fiber mixture were used. × 51m
m polyester fiber: 80%, 2 denier x 51 mm
Core-sheath type binder fiber (sheath melting point 110 ° C):
20% thickness 20 mm, average apparent density 0.04 g / c
using polyester nonwoven fabric of m ³ on the inner surface layer, creating the automotive sound insulation structure by laminating.

(Example 9) An ultrafine nonwoven fabric made of polypropylene having an average fiber diameter of 3 μm, a thickness of 10 mm, and an average apparent density of 0.05 g / cm ³ , obtained by a melt blow method, was used as a surface layer, and a fiber blend of 2 denier × 51 mm was used. Polyester fiber: 80%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 20% thick, 20 mm thick, non-woven fabric made of polyester having an average apparent density of 0.06 g / cm ^{3 in} the inner layer, An ultrafine nonwoven fabric made of polypropylene having an average fiber diameter of 3 μm, a thickness of 6 mm, and an average apparent density of 0.04 g / cm ³ obtained by a melt-blowing method was used as a back layer and laminated to produce a sound insulating structure for automobiles.

(Example 10) An ultrafine nonwoven fabric made of polypropylene having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt-blowing method was used as a surface layer, and a fiber blend of 13 denier × 51 mm was used. Polyester fiber: 80%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 20%, 30 mm in thickness, and a polyester nonwoven fabric having an average apparent density of 0.05 g / cm ^{3 in} the inner surface layer, An ultrafine nonwoven fabric made of polypropylene having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.04 g / cm ³ obtained by a melt blow method was used as a back layer, and laminated to produce a sound insulating structure for automobiles.

(Conventional Example 1) In an injection foaming mold having a clearance of 30 mm, propylene oxide 1,2,6-hexanetriol: 100 parts as a polyol, water:
Liquid A consisting of 2 parts, surfactant: 1 part, carbon black: 0.5 part and tolylene diisocyanate: 100 parts,
Silicone oil: B liquid consisting of 0.5 part was injected at a low pressure with 1.25 times equivalent of isocyanate to the polyol and foamed to a thickness of 30 mm and an average apparent density of 0.06 g / c.
m ³ urethane foam was obtained to provide a sound insulating structure for automobiles.

(Conventional example 2) 30 m thick, manufactured by Howa Textile Industry
m, a felt (trade name: Feltop) having an average apparent density of 0.06 g / cm ³ was used as an automobile sound insulation structure.

(Conventional example 3) Fiber blend 6 denier × 51 m
m polyester fiber: 80%, 2 denier x 51 mm
Core-sheath type binder fiber (sheath melting point 110 ° C):
20%, thickness 30mm, average apparent density 0.05g / c
using polyester nonwoven fabric of m ^3, and the automotive sound insulation structure.

(Conventional Example 4) A sound insulating structure for automobiles was prepared using a polypropylene ultra-fine fiber nonwoven fabric having an average fiber diameter of 3 μm, a thickness of 30 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt blow method.

(Comparative Example 1) Fiber blend 6 denier x 51 m
m polyester fiber: 80%, 2 denier x 51 mm
Core-sheath type binder fiber (sheath melting point 110 ° C):
20% thickness 20mm, average apparent density 0.05g / c
The polyester nonwoven fabric of m ³ is used for the surface layer, and the ultrafine nonwoven fabric made of polypropylene having an average fiber diameter of 3 μm, a thickness of 8 mm, and an average apparent density of 0.05 g / cm ³ obtained by a melt blow method is used for the inner surface layer. A sound insulation structure for an automobile was created.

(Comparative Example 2) Fiber blend 6 denier x 51 m
m polyester fiber: 80%, 2 denier x 51 mm
Core-sheath type binder fiber (sheath melting point 110 ° C):
20% thickness 10mm, average apparent density 0.05g / c
m ³ polyester nonwoven fabric on the surface layer, average fiber diameter 3 μm, thickness 20 mm obtained by melt blown method,
An ultra-fine nonwoven fabric made of polypropylene having an average apparent density of 0.05 g / cm ³ was used as an inner layer and laminated to form a sound insulating structure for an automobile.

(Comparative Example 3) A nonwoven fabric made of polypropylene ultrafine fibers having an average fiber diameter of 3 μm, a thickness of 2 mm, and an average apparent density of 0.04 g / cm ³ obtained by a melt blow method was used as a surface layer, and a fiber blend of 6 denier × 51 mm was used. Polyester fiber: 80%, 2 denier × 51 mm core-sheath type binder fiber (sheath melting point: 110 ° C.): 20%, thickness: 30 mm, polyester nonwoven fabric having an average apparent density of 0.05 g / cm ³ is used for the inner surface layer. And laminated to form a sound insulating structure for an automobile.

(Comparative Example 4) Fiber blend 6 denier x 51 m
m polyester fiber: 80%, 2 denier x 51 mm
Core-sheath type binder fiber (sheath melting point 110 ° C):
20% thickness 10mm, average apparent density 0.05g / c
m ³ polyester non-woven fabric for the surface layer and the back layer, and a polypropylene ultra-fine fiber non-woven fabric having an average fiber diameter of 3 μm, a thickness of 10 mm, and an average apparent density of 0.04 g / cm ³ obtained by a melt-blow method. The layers were laminated to create a sound insulation structure for an automobile.

(Comparative Example 5) Fiber blend 6 denier x 51 m
m polyester fiber: 80%, 2 denier x 51 mm
Core-sheath type binder fiber (sheath melting point 110 ° C):
8% thick at 20%, average apparent density 0.05 g / cm
³ polyester nonwoven fabric on the surface layer and the back layer, the average fiber diameter obtained by the melt blow method is 3 μm, and the thickness is 3
An ultra-fine nonwoven fabric made of polypropylene having a thickness of 0 mm and an average apparent density of 0.04 g / cm ³ was used as an inner layer and laminated to form a sound insulating structure for automobiles.

(Evaluation of Performance) The sound-absorbing structures for automobiles obtained in Examples 1 to 10, Conventional Examples 1 to 3, and Comparative Examples 1 to 5 were measured for a normal incidence sound absorption coefficient of 100 to 1600 Hz. The spring constant was determined from the resonance frequency using the vibration transmissibility measurement method. In the vibration transmissibility measuring method, the whole spring constant is obtained from the measurement in the atmosphere, and the fiber spring constant is obtained from the measurement in a vacuum, and the difference is the air spring constant. Table 1 shows the physical property data of each Example, Conventional Example and Comparative Example,
The measurement results of the sound absorption coefficient (500 Hz, 1000 Hz) and the measurement results of each spring constant are shown.

[0046]

[Table 1]

From Table 1, it can be seen that the various types of sound insulation structures for automobiles prepared in the examples have a low spring constant while maintaining a high sound absorption coefficient as compared with the conventional example, and have high sound absorption and low spring. It was confirmed that this was a compatible sound insulation structure for automobiles. Further, from Table 1, the sound insulating structure for a vehicle of the comparative example, which is not within the scope of the present invention, did not achieve both high sound absorption and low spring, and was compared with the sound insulating structure for a vehicle of the example. It was confirmed that the performance was inferior.

[0048]

As described above, according to the present invention, according to the present invention, the sound insulating structure is multi-layered and the ultrafine fiber non-woven fabric is disposed on the surface layer serving as the main sound incident surface, and the thickness and density of the surface layer and the opposite are obtained. Since the thickness and density of the inner surface layer located on the side have been specified, the high sound absorption and high sound insulation (low It is possible to provide a sound insulation structure for an automobile that is compatible with springing.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration example (two layers) of a sound insulation structure of the present invention.

FIG. 2 is a schematic diagram showing a configuration example (three layers) of the sound insulation structure of the present invention.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI E04B 1/82 E04B 1/82 H 1/86 1/86 NG10K 11/162 G10K 11/16 A 11/16 D

Claims (6)

[Claims] 1. A laminated structure comprising two or more fiber aggregates having different fiber blends, wherein a surface layer serving as a main sound incident surface has a fiber diameter of 0.1 obtained by a melt blow method.
Average apparent density of 0.03 to 10 μm fibers
It is a nonwoven fabric made of polypropylene having a thickness of 0.06 g / cm ³ and a thickness of 5 to 15 mm, wherein the thickness of the inner surface layer located on the opposite side to the sound incident surface is 2 to 5 times the surface layer. Automotive sound insulation structure. 2. The laminated structure has a three-layer structure consisting of a surface layer, an inner layer and a back layer in order from the main sound incident direction, and the fiber diameter of the surface layer and the back layer obtained by a melt blow method. Average apparent density of fibers of 0.1-10 μm 0.03-0.06 g / cm ³ , thickness 5-15
2. The automobile according to claim 1, wherein the inner layer is 2 to 5 times the thickness of the thicker one of the surface layer and the back layer. 3. For sound insulation structure. ^3. The polyester nonwoven fabric according to claim 1, wherein the inner surface layer is a polyester nonwoven fabric having an average apparent density of 0.01 to 0.07 g / cm ³ made of polyester fibers having a fiber diameter of 1 to 50 denier. 3. The sound insulation structure for vehicles according to 2. 4. The nonwoven fabric constituting the inner surface layer is composed of at least two kinds of polyester fibers, wherein fiber 1 occupying 60 to 95% by weight is polyethylene terephthalate fiber, and fiber 2 occupying 5 to 40% by weight is sheath. 4. The sound insulation structure for an automobile according to claim 3, wherein the polyester fiber has a core-sheath structure which is a copolymerized polyester having a melting point of 100 ° C. or lower than that of the fiber 1. 5. The thickness of the entire laminated structure is 20 to 50.
mm.
4. The sound insulation structure for an automobile according to any one of the above items. 6. The sound insulating structure for an automobile according to claim 5, wherein the sound insulating structure is used as a dash insulator or a floor insulator of a vehicle.