JP3342817B2 - Sound insulation structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-walled sound insulation structure installed to prevent external vibration and / or noise from entering, and more particularly to vibration and noise from floor steel plates of automobiles. Suitable for floor insulator carpets etc. installed to prevent / block noise. Further, the sound insulating structure of the present invention is one in which air permeability is particularly controlled in order to improve sound insulating performance in a low frequency region.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 1, a floor insulator for an automobile has a sound insulation structure 2 located on the interior side of a floor panel 1 which divides the interior of the vehicle from the outside, and transmits noise from outside to the interior of the vehicle. Has the role of preventing The conventional sound insulating structure 2 has a low-density layer 3 made of a porous base material such as felt, polyurethane foam, or non-woven fabric as shown in the figure, and has no air permeability such as an EVA material sheet or a polyethylene sheet mixed with a filler. It is composed of a laminated structure of the high density layer 4. The low-density layer 3 absorbs noise from outside the vehicle, and the double-walled structure in which the low-density layer 3 is interposed between the floor panel 1 and the high-density layer 4 provides a good sound insulation effect. It is configured to exhibit soundproof performance. 5 is a carpet skin.

[0003]

In such a conventional double-walled sound insulation structure of a floor insulator, the high-density layer 4 does not have air permeability, so that it has excellent sound insulation performance in a high frequency range. In the low frequency range, which is important for the sound insulation performance of floor components, a decrease in performance near the resonance point is observed, and the superiority of the mass rule of sound transmission loss (TL) determined by the mass of the entire laminated structure over the sound insulation level is small. .

The present invention has been made in view of such circumstances, and in a sound-insulating structure made of a molded article having air permeability, the performance near the resonance point is improved by controlling the air permeability. It is an object of the present invention to provide a sound insulating structure having improved sound insulating performance in a low frequency range.

[0005]

The above object is achieved by laminating at least two layers of non-woven fabrics having different air permeability.
Surface density (basis weight) of ~ 3.0 kg / cm ² and 16 ~ 60m
m, and the difference in air flow between each layer is 450 to 1000 at an air pressure of 0.01 kg / cm ² .
cc / cm ² · min. This is achieved by a sound insulation structure characterized by the following.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, in order to impart sufficient sound insulating performance to a laminate, at least one of the high-density layers has a sufficient ventilation resistance so as to form a double wall structure with an external partition, and It is necessary to control the low-density layer to the airflow resistance necessary for improving its sound absorption coefficient and reducing the spring constant. For this purpose, the difference in air flow between the high-density layer and the low-density layer is determined by adjusting the air pressure to 0.01 kg / cm.
^{2 at} 450 to 1000 cc / cm ² · min. Must be within the range. 450cc / ventilation difference
cm ² · min. If it is less than the above, it is substantially the same as the single-layer structure, and does not form a double wall structure. Ventilation difference is 100
0 cc / cm ² · min. If it exceeds, the target of the sound insulation performance of the low-density layer cannot be achieved.

[0007] The surface density of the entire laminate is 0.5 to 3.0 k.
g / m ² . In order to ensure sound insulation performance, the higher the areal density of the laminate, the better, but 3.0 kg /
If it exceeds m ² , it is undesirably too heavy for practical use. On the other hand, if the areal density is less than 0.5 kg / m ² , the object of improving sound insulation performance such as sound absorption performance cannot be achieved.

[0008] The total thickness of the laminate must be in the range of 16 to 60 mm. If the surface density in the above range is less than 16 mm, the air permeability becomes too small, and it is not possible to obtain a sufficient sound insulating performance especially near the resonance point in a low frequency region. The thickness is preferably as large as possible to improve the sound absorbing performance. However, if the thickness exceeds 60 mm, it is not preferable from the viewpoint of securing a space for practical use.

Next, the high-density layer will be described. In order to improve the sound insulation performance by attaching the sound insulation structure of the present invention to an outer partition, for example, the interior side of the floor panel of an automobile, the high-density layer is required to reduce its air permeability, It is necessary to form a sound insulation structure.

First, it is effective to reduce the ventilation rate to improve the sound insulation performance. The air permeability of the non-woven fabric layer depends on various factors such as the density of the layer determined by its surface density and thickness, the fiber diameter of the constituent fibers, the cross-sectional shape of the fibers, and the like. Reducing the average diameter of the fibers to be formed is extremely effective in reducing air permeability. However, relying on mere increase in density leads to an increase in overall weight, which is disadvantageous in that it is not suitable for mounting on a vehicle, but also increases material costs.

Second, it is already known that the effect of improving the sound insulation performance increases when the outer partition and the high-density layer form a double-walled structure via the low-density layer. However, even in such a double-walled structure, in order to further improve the sound insulation performance while avoiding the disadvantages such as the increase in weight described above, physical properties such as air permeability and rigidity are required by operations such as fiber blending, surface density, and thickness. Is desirably controlled appropriately. Therefore, the sound insulating structure of the present invention firstly sets the air permeability of the high-density nonwoven fabric layer to the structure and composition of the constituent fibers so as to form a double-walled sound insulating structure exhibiting excellent sound insulating performance with the external partition walls. It is important to mainly control the selection of the areal density and the thickness in a suitable range.

The high-density layer is preferably made of a fiber-forming linear polymer, typically a polyester mainly composed of polyethylene terephthalate, and has a diameter of 10 to 25 μm and a fiber of 30 to 100 mm in circular cross section or irregular shape. It is a nonwoven fabric composed of short fibers having a cross-sectional fiber, and has an air permeability of 700 to 1250 cc / at an air pressure of 0.01 kg / cm ² .
cm ² · min. It is preferable that

The air permeability changes depending on the fiber diameter, surface density, and thickness of the constituent fibers. The smaller the fiber diameter, that is, the larger the surface area of the fiber in the nonwoven fabric, the higher the airflow resistance and the lower the air permeability. However, fine denier fibers are expensive and have poor carding properties, making it difficult to form a nonwoven fabric. Therefore, a fineness of less than 10 μm in fiber diameter is not preferable in terms of economy and moldability. On the other hand, if it exceeds 25 μm, sufficient ventilation resistance cannot be obtained, and it is difficult to improve the sound insulation performance.

The fiber length of the constituent fibers is from 30 to 10 in view of the effect on the fiber surface area in the nonwoven fabric, the workability in producing the nonwoven fabric such as carding characteristics, and the improvement of the mechanical strength of the nonwoven fabric.
It is preferably 0 mm. If the fiber length is less than 30 mm, the workability during the production of the nonwoven fabric is inferior. If it exceeds 100 mm, it is difficult to uniformly disperse the nonwoven fabric in the nonwoven fabric, and it is difficult to form a good and uniform quality nonwoven fabric layer.

A more preferred embodiment of the high-density nonwoven fabric layer comprising short fibers mainly composed of polyester is a fiber having a fiber diameter of 10 to 2
5 μm, a circular or irregular cross-section fiber (fiber A) having a fiber length of 50 to 100 mm has a softening point of at most 80% by weight, a softening point at least 20 ° C. lower than the softening point of fiber A, and a fiber diameter of 10 to 10.
Fibers having a fiber length of 20 μm and a fiber length of 30 to 100 mm (hereinafter also referred to as “fiber B” or “binder fiber”) are at least 20% by weight. When the fiber A is fine denier with a fiber diameter of less than 10 μm, as described above, it is difficult to manufacture the fiber A stably because it is technically difficult to manufacture, and the cost is increased.
It is difficult to obtain a uniform non-woven fabric because it is difficult to mix with the non-woven fabric, which is not preferable in terms of both economic efficiency and moldability. On the other hand, if the fiber diameter exceeds 25 μm, sufficient airflow resistance cannot be obtained, and it is difficult to improve the sound insulation performance. In addition, irregularly shaped short fibers further contribute to an increase in airflow resistance. On the other hand, if the amount of the fiber A exceeds 80% by weight based on the weight of the high-density layer, it is difficult to control the thickness of the sound absorbing material, and it is difficult to secure a sufficient density.

Further, when the sound insulation structure of the present invention is used in addition to an uneven surface of, for example, a floor panel of an automobile, the sound insulating structure can follow the uneven surface shape and can be molded in a state of being in close contact therewith. Not only is it important, but also a major factor in improving sound insulation performance. The sound-insulating structure having the fiber A as a skeleton follows the shape of the mold well because the surface density and thickness are limited and short fibers are used as described above.
In this state, when heat molding is performed at an appropriate temperature between the softening points of the fibers A and the binder fibers, the binder fibers soften and exhibit adhesiveness, and the intersections between the fibers are joined to stabilize the form of the nonwoven fabric.

When the difference between the softening points of the fibers A and B is less than 20 ° C., only the fibers B are softened and bonded in a state in which the strength and rigidity of the fibers A are suppressed from decreasing during the heat molding and the shape of the nonwoven fabric is maintained. It becomes extremely difficult to control the temperature to develop
The risk of causing softening of the entire nonwoven fabric increases.

Binder fibers having a fiber diameter of less than 10 μm are unusual and costly, causing settling (permanent crush deformation) of the binder fibers themselves during heat molding, and the fiber A
It is also difficult to obtain a uniform nonwoven fabric, which is not preferable in terms of both economic efficiency and moldability. On the other hand, when the fiber diameter of the binder fiber exceeds 20 μm, the number of fibers relatively decreases with an increase in the fiber diameter, so that the number of bonding points between constituent fibers decreases, and the shape stability and moldability decrease. It is not preferable. When the amount of the fiber B is less than 20% by weight based on the weight of the high-density layer, sufficient molding properties cannot be imparted to the high-density layer due to a decrease in the number of bonding points.

As the fiber material, the above polyester is suitable from the viewpoints of flowability, mechanical strength, rigidity and the like, and has high cost performance. In addition, polyamide-based polyamides such as nylon, polyvinyl-based such as polyacrylonitrile, and polyethylene, a fiber-forming synthetic polymer such as a polyolefin such as polypropylene, or a semi-synthetic polymer such as cellulose acetate can also be used. By producing the fiber and converting it into a nonwoven fabric, a material having substantially the same airflow resistance can be obtained.

As the binder fiber, a polymer having an affinity for the fiber A, for example, when the fiber A is a homopolyester polymer fiber, the binder fiber is also made of polyester and has another dibasic acid component and / or glycol component. Copolymers or blended polymer fibers whose softening point has been lowered by copolymerizing or blending are preferably used. More preferred is a conjugate fiber comprising such a copolymer or blend polymer as a sheath component and a homopolymer as a core component. In such a conjugate fiber, the core component performs a supporting function without softening or melting while the sheath component performs the bonding function.

Next, the areal density of the high-density layer suitable for ensuring the sound insulation performance by forming the double-walled structure with the non-woven fabric of the high-density layer together with the outer partition walls is in the range of 0.1 to 1.0 kg / m ² . It is in. If the areal density is less than 0.1 kg / m ^2, the improvement of the sound insulation performance is insufficient, while if it exceeds 1.0 kg / m ² , it is not preferable from the viewpoint of an increase in material cost and weight.

The non-woven fabric of the high-density layer having a surface density in the above range preferably has a thickness of 1 to 10 mm. 1mm
A high-density layer having a thickness less than the above and having the above-mentioned surface density is difficult to mold, and even if moldable, it is not preferable because the molded article has excessively high airflow resistance and, on the contrary, deteriorates sound insulation performance. On the other hand, if it exceeds 10 mm, it is difficult to obtain a sufficient ventilation resistance for exhibiting sound insulation performance in the above-mentioned area density range, which is not preferable.

The high-density nonwoven fabric layer formed by the above-mentioned fiber type and fiber composition has an air permeability of 0.01 kg / air.
In cm ² 700~1250cc / cm ² · mi
n. , Leading to excellent sound insulation performance. The airflow resistance is too high and the airflow is 700 cc / cm ² · min.
If it is less than 1, the sound insulation performance particularly near the resonance point in the low frequency region is remarkably reduced, and it is difficult to overcome the conventional problems, so that it is not preferable, and 1250 cc / cm ² · min.
On the other hand, if it exceeds, the airflow resistance is insufficient and it is difficult to form an effective double-walled sound insulation structure with the external partition, which is not preferable.

Next, the low density layer will be described. In order to improve the sound insulation performance of the sound insulation structure of the present invention, it is necessary to control the air permeability of the low density layer, reduce the vibration transmissibility, and improve the sound absorption rate, in combination with the air permeability control of the high density layer. It is.

First, the airflow resistance, which is an index of air permeability, is:
As described in the description of the high-density layer, it changes depending on the fiber diameter, the surface density, and the thickness.

Second, the sound insulation performance improves as the vibration transmission rate decreases. Here, the vibration transmissibility greatly depends on the dynamic spring constant of the object. Therefore, it is necessary to reduce the dynamic spring constant to improve the sound insulation performance. The spring constant changes depending on the fiber diameter.

Third, the higher the sound absorption coefficient of the low density layer, the better the sound insulation performance. The sound absorption coefficient depends on various factors such as the density of the layer determined by the surface density and the thickness of the nonwoven fabric layer, the fiber diameter of the constituent fibers, the fiber cross-sectional shape, etc. Among them, increasing the surface density and configuring the nonwoven fabric Reducing the average diameter of the fibers is extremely effective in improving the sound absorption coefficient. However, relying solely on the increase in density leads to an increase in the overall weight, which is not only unsuitable for mounting on a vehicle, but also has the disadvantage of increasing material costs.

The fibers constituting the low-density layer of the sound insulation structure of the present invention preferably have a fiber diameter of 10 to 40 μm and a fiber length of 30 to 100 mm. The smaller the fiber diameter,
In other words, as the fiber surface area in the nonwoven fabric increases, the airflow resistance increases and the air permeability decreases. At the same time, the smaller the fiber diameter, the better the sound absorption performance. However, fine denier fibers with a fiber diameter of less than 10 μm are expensive, so the cost is low. This is not preferable because of increasing the carding properties and the poor formability of the nonwoven fabric. On the other hand, if it exceeds 40 μm, the ventilation resistance and the sound absorption performance are significantly reduced at the same time, so that it is difficult to improve the sound insulation performance.

From the viewpoint of the effect on the fiber surface area in the nonwoven fabric, the workability in producing the nonwoven fabric such as carding characteristics, and the improvement of the mechanical strength of the nonwoven fabric, the fiber length of the constituent fibers is 30 to 10%.
It is preferably 0 mm. If the fiber length is less than 30 mm, the workability during the production of the nonwoven fabric is inferior. If it exceeds 100 mm, it is difficult to uniformly disperse the nonwoven fabric in the nonwoven fabric, and it is difficult to form a good and uniform quality nonwoven fabric layer.

As a fiber material, the above-mentioned polyester is suitable from the viewpoints of flowability, mechanical strength, rigidity and the like, similarly to the high-density layer, and has high cost performance. Further, synthetic polymers such as polyamides such as nylon, polyvinyls such as polyacrylonitrile, and polyolefins such as polyethylene and polypropylene, or semi-synthetic polymers such as cellulose acetate can also be used. By forming a nonwoven fabric, a material having substantially the same airflow resistance can be obtained.

The suitable areal density of the low-density nonwoven fabric layer for ensuring its sound insulation performance is in the range of 0.4 to 2.0 kg / m ² . If the areal density is less than 0.4 kg / m ^2, the improvement of the sound insulation performance is insufficient, while if it exceeds 2.0 kg / m ² , it is not preferable from the viewpoints of increase in material cost and weight.
Also, since the spring constant increases with the areal density of the nonwoven fabric layer and deteriorates the vibration transmissibility, it should be avoided to exceed 2.0 kg / m ² .

The low-density nonwoven fabric layer having a surface density in the above range preferably has a thickness of 15 to 50 mm. 15m
When the thickness is less than m, the difference in density from the high-density nonwoven fabric layer becomes small and the double-wall structure is not substantially formed, so that the sound absorption performance is reduced. On the other hand, when the thickness is more than 50 mm, the space for practical use is secured. It is not preferable because it is not appropriate.

The low-density nonwoven fabric layer formed by the above fiber type and composition has an air permeability of 0.01 kg / air.
In cm ² 1700~1950cc / cm ² · mi
n. , Leading to excellent sound insulation performance. When the ventilation rate is 1700 cc / cm ² · min. If it is less than 1, the airflow resistance is excessively increased, and the sound insulation performance near the resonance point is remarkably deteriorated, and it is difficult to overcome the conventional problems, so that it is not preferable, and 1950 cc / cm ² · min. On the other hand, if it exceeds, the airflow resistance is insufficient and it is difficult to form an effective double-walled sound insulation structure with the external partition, which is not preferable.

Further, a more preferable embodiment of the low-density nonwoven fabric layer constituting the sound insulating structure of the present invention is a fiber diameter of 10 to 40 μm.
m, the fiber (fiber C) having a fiber length of 50-100 mm is 70-
90% by weight and a softening point at least 20 ° C. lower than the softening point of the fiber C, a fiber diameter of 10 to 20 μm, and a fiber length of 30 to
100 mm fiber (fiber B or binder fiber) 1
0 to 30% by weight. Such a low-density nonwoven fabric layer mainly functions to control air permeability, reduce vibration transmission, and improve sound absorption.

If the fiber C has a fine denier with a fiber diameter of less than 10 μm, as described above, it is difficult to manufacture it technically, so that it is difficult to supply the fiber C stably, the cost increases, and the uniform nonwoven fabric is hardly mixed with other fibers C. Is difficult to obtain, which is not preferable from both aspects of economy and moldability. In order to improve the sound insulation performance and reduce the amount of ventilation, it is desirable to incorporate a large amount of fine fibers, but this reduces the shape retention characteristics of the low-density layer and causes sagging to meet the required performance. There is a possibility that the required thickness cannot be secured. Therefore, it is desirable to mix fibers having a fineness equal to or relatively large as compared with the fibers A mixed in the high-density layer. However, if the fiber diameter exceeds 40 μm, sufficient airflow resistance cannot be obtained, which is not suitable for obtaining good sound insulation performance. On the other hand, if the amount of the fiber C exceeds 90% by weight based on the weight of the low-density layer, it is difficult to control the thickness of the sound absorbing material, and it is difficult to secure a sufficient density. On the other hand, if the amount is less than 70% by weight, it is not preferable from the viewpoint of reducing the spring constant and ensuring the formability.

In the laminated structure of the present invention, a double-walled sound insulation structure is formed by attaching at least one of the high-density layers and the external partition to the external partition. As a characteristic of such a double-walled sound insulation structure, a resonance phenomenon occurs at a certain frequency on a sound insulation performance curve. Therefore, by shifting the resonance point to a lower frequency side, the entire sound insulation performance curve with respect to the frequency can be shifted to the lower frequency side to improve the performance. In the double-wall sound insulation structure of the present invention, the resonance point can be set arbitrarily. That is, by appropriately adjusting the fiber composition, density, air permeability, rigidity and elastic modulus of the high-density layer, and the fiber composition, thickness, density, dynamic spring constant and air permeability of the low-density layer, the primary resonance can be achieved. The frequency can be set to any frequency between 50 and 300 Hz.

The primary resonance frequency (f) of a double-walled sound insulation structure having a low-density layer as an intermediate layer is generally represented by the following (1).
It is approximated by an equation.

[0038]

F = 1 / 2π · [｛(m ₁ + m ₂ ) / m ₁ · m ₂ ｝ · E / d] ¹ / _2- (1) where m ₁ and m ₂ are external partition walls And E are the surface densities of the high-density layer, E is the Young's modulus of the low-density layer, d is the thickness of the low-density layer, and the Young's modulus is calculated from the elastic modulus and the like.

However, since the double-walled sound insulation structure constructed according to the present invention does not form a complete double-walled structure, the primary resonance frequency cannot be determined only by equation (1). Therefore, as a specific means to set the resonance point arbitrarily, to set a low frequency, operate the fiber blending of the high density layer within the above range, increase the thickness, increase the density, and increase the dynamic spring constant and ventilation. A method of reducing the amount is effective. Performing all of these at the same time enables more precise resonance point setting, but is not particularly limited.

In the laminated structure of the present invention, the primary resonance frequency is preferably set to a frequency of 50 to 300 Hz.
Setting the resonance point at a frequency higher than 300 Hz is not preferable because the sound insulation performance is reduced at a low frequency of 1 kHz or less. Setting the resonance point at less than 50 Hz is not preferable because the density increase in the above operation increases, leading to an increase in weight.

Next, comparison of sound insulation performance according to the mass law will be described. In the double-walled sound-insulating structure using the sound-insulating structure of the present invention, the double-walled sound-insulating structure has a frequency of 300 Hz with respect to the sound insulation level of the mass rule of sound transmission loss (TL) determined by the mass of the entire laminated structure. In the frequency range of １1 kHz, the sound transmission loss is improved by 1 to 3 dB on the average frequency.

The mass of the entire laminated structure constituting the sound insulation structure is one of the factors that determine the sound insulation performance. The mass rule is that the sound insulation performance for each frequency is determined by the mass of the sound insulation structure. However, when the laminated structure forms a double-walled sound insulation structure together with the outer partition, as described above, the sound insulation performance is lower than the mass law in the resonance region, but can be higher than the mass law in other regions. Therefore, by forming a double-walled sound insulation structure and operating the resonance point as described above, it becomes possible to improve the sound insulation performance in an arbitrary frequency region. The sound insulation structure of the present invention can be made 3
In the frequency range of 00 Hz to 1 kHz, it is possible to exceed the sound insulation level of the mass rule of sound transmission loss (TL) by 1 to 3 dB.

Next, application to a floor insulator for an automobile will be described. It is important in terms of required specifications to ensure sound insulation performance in a low-frequency region, particularly 1 kHz or lower, of floor components for automobiles. However, the sound insulation structure of the present invention sufficiently meets such specifications required for floor insulators for automobiles. Can be satisfied. Further, since the resonance point can be set arbitrarily, it is possible to further improve the sound insulation performance in a low frequency region.

In addition, polyester is often used for the carpet skin used for floor insulators for automobiles. By combining with the sound insulating structure of the present invention, the entire floor insulator can be manufactured from polyester, which is generated in the process. The recyclability of burrs and the like can be improved.

The sound-insulating structure of the present invention has air permeability and excellent sound insulation performance in a low-frequency region as compared with a conventional product having at least one high-density layer having no air permeability and having the same shape and the same weight. Having.

The method for producing a sound insulating structure of the present invention comprises the steps of: forming a short-fiber web of a high-density layer having low air permeability, preferably made of polyester; and a short-fiber web of a low-density layer having high air permeability, preferably made of polyester. They are manufactured separately, and both are laminated and integrated by needle punching and / or heat molding.

More specifically, the fiber diameter is 10 to 25 μm,
Fiber raw material blended with short fibers having a fiber length of 30 to 100 mm, or at least 20% by weight of binder fibers having a softening point at least 20 ° C. lower than the softening point of the fiber and having a fiber diameter of 10 to 20 μm and a fiber length of 30 to 100 mm. Is subjected to a carding and lapping step by a conventional method to form a web for a high density layer having a predetermined basis weight. Similarly, carding and wrapping of a fiber material having a fiber diameter of 10 to 40 μm and a fiber length of 30 to 100 mm, or preferably, a fiber raw material obtained by blending 70 to 90% by weight of the fiber with 10 to 30% by weight of the binder fiber is performed. Through the steps, a low density layer web having a predetermined basis weight is formed. Next, these short fiber webs are formed into a web laminate by a plurality of continuous cross layers, and thereafter the whole is integrated by needle punching, and heat-set as necessary, and 0.5 to
It is formed into a laminate having an area density of 3.0 kg / cm ² and a thickness of 16 to 60 mm.

[0048]

The present invention will be described below in more detail with reference to Examples.

The measuring method of each characteristic value in the following examples and comparative examples is as follows. 1. Ventilation resistance For each sample, JIS L1004, L101
8, and the air permeability was measured according to the measurement method of the air permeability test specified in L1096. 2. Sound insulation performance For each sample, refer to JIS A1416 “Reverberation room-
Sound transmission loss measurement using a reverberation room ". At this time, the areal density is unified for each sample, and the sound transmission loss (T
The sound insulation performance difference was calculated using the sound insulation level of the mass rule of L) as a 0 dB reference. Further, this difference is set to 300-500 Hz, 50
The values were averaged at a frequency of 0 Hz to 1 kHz and summarized in a graph.

(Example 1) The high-density layer had an area density of 200 g /
cm ² , thickness 2 mm, fiber diameter 14 μm, fiber length about 50
50% by weight of polyester fiber A having a fiber diameter of 14 mm.
μm, a fiber length of about 50 mm, and a softening point of 90% lower than that of the fiber A by 50% by weight of a polyester fiber B. The air permeability is 1000 cc at an air pressure of 0.01 kg / cm ² .
/ Cm ² · min. And the low density layer has an area density of 875 g.
/ Cm ^2, a thickness of 35 mm, fiber diameter 25 [mu] m, and 90 wt% polyester fiber C and a fiber length of about 50 mm, fiber diameter 14 [mu] m, the softening point than the fiber C with a fiber length of about 50 mm 90
10% by weight of polyester fiber B lower by 10 ° C.,
The ventilation rate is 1700 at an air pressure of 0.01 kg / cm ² .
cc / cm ² · min. The sound insulation structure (1) was produced using each nonwoven fabric. The primary resonance point was set to 200 Hz by attaching this to an external partition.

Example 2 The high-density layer had an area density of 100 g.
/ Cm ² and an air flow rate of 1150 cc / cm ² · min. At an air pressure of 0.01 kg / cm ² . A sound insulation structure (2) was produced in exactly the same manner as in Example 1 except for the above.

Example 3 The high-density layer had an area density of 1000
g / cm^Two, Air flow rate 0.01kg / cm ^TwoIn
700cc / cm^Two-Min. Example except for
A sound insulation structure (3) was produced in exactly the same manner as in (1).

(Example 4) Thickness of a high-density layer was 1 mm, and air permeability was 1000 c at an air pressure of 0.01 kg / cm ² .
c / cm ² · min. A sound insulation structure (4) was produced in exactly the same manner as in Example 1, except that

(Example 5) The thickness of the high-density layer was 10 mm,
The air flow rate is 750 c at an air pressure of 0.01 kg / cm ² .
c / cm ² · min. A sound insulation structure (5) was produced in exactly the same manner as in Example 1, except that

Example 6 The high-density layer has a fiber diameter of 10 μm,
50% by weight of a polyester fiber A having a fiber length of 50 mm,
It is composed of 50% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm, and a softening point lower by 90 ° C. than that of the fiber A, and having an air permeability of 95 kg / cm ^{2 at} an air pressure of 0.01 kg / cm ² .
0 cc / cm ² · min. A sound insulating structure (6) was produced in exactly the same manner as in Example 1 except for the following.

Example 7 The high-density layer had a fiber diameter of 25 μm,
50% by weight of a polyester fiber A having a fiber length of 50 mm,
A polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm, and a softening point of 90 ° C. lower than that of the fiber A is constituted by 50% by weight, and the air permeability is 11 at an air pressure of 0.01 kg / cm ² .
00 cc / cm ² · min. A sound insulating structure (7) was produced in exactly the same manner as in Example 1 except for the following.

Example 8 The high-density layer had a fiber diameter of 14 μm.
50% by weight of a polyester fiber A having a fiber length of 30 mm,
It is composed of 50% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm, and a softening point lower by 90 ° C. than that of the fiber A, and having an air permeability of 95 kg / cm ^{2 at} an air pressure of 0.01 kg / cm ² .
0 cc / cm ² · min. A sound insulating structure (8) was produced in exactly the same manner as in Example 1 except for the following.

Example 9 The high-density layer had a fiber diameter of 14 μm,
50% by weight of 100 mm polyester fiber A
With a fiber diameter of 14 μm and a fiber length of 50 mm, softened from fiber A
The polyester fiber B whose point is lower by 90 ° C. is composed of 50% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
1050cc / cm^Two-Min. Example 1 except that
A sound insulation structure (9) was produced in exactly the same manner as in (1).

Example 10 The high-density layer had a fiber diameter of 14 μm.
m, consisting of only polyester fiber B having a fiber length of 50 mm and a softening point 90 ° C. lower than that of the fiber A, and having a ventilation volume of 1250 cc / cm ^{2 at} an air pressure of 0.01 kg / cm ^2.
min. A sound insulation structure (10) was produced in exactly the same manner as in Example 1 except for the following.

Example 11 The high-density layer had a fiber diameter of 14 μm.
80% by weight of polyester fiber A having a fiber length of 50 mm
And 20% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm and a softening point lower than that of the fiber A by 90 ° C., and a ventilation rate of 900 cc / cm ² · min. At an air pressure of 0.01 kg / cm ² . A sound insulation structure (11) was produced in exactly the same manner as in Example 1 except for the following.

Example 12 The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 50 mm
And 50% by weight of a polyester fiber B having a fiber diameter of 10 μm, a fiber length of 50 mm and a softening point lower than that of the fiber A by 90 ° C., and a ventilation rate of 950 cc / cm ² · min. At an air pressure of 0.01 kg / cm ² . A sound insulating structure (12) was produced in exactly the same manner as in Example 1 except for the following.

Example 13 The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 50 mm
And 50% by weight of a polyester fiber B having a fiber diameter of 20 μm, a fiber length of 50 mm and a softening point lower than that of the fiber A by 90 ° C., and a ventilation rate of 1100 cc / cm ² · min. At an air pressure of 0.01 kg / cm ² . Example 1 except that
A sound insulation structure (13) was produced in exactly the same manner as in (1).

Example 14 The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 50 mm
And 50% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 30 mm and a softening point lower than that of the fiber A by 90 ° C., and a ventilation rate of 950 cc / cm ² · min. At an air pressure of 0.01 kg / cm ² . A sound insulating structure (14) was produced in exactly the same manner as in Example 1 except for the following.

(Example 15) The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 50 mm
With a fiber diameter of 14 μm and a fiber length of 100 mm, it is softer than fiber A
50% by weight of polyester fiber B whose crystallization point is 90 ° C lower
Constructed and air flow rate is 0.01kg / cm ^Twosmell
1050cc / cm^Two-Min. Examples other than
A sound insulation structure (15) was produced in exactly the same manner as in Example 1.

Example 16 The low-density layer had an area density of 400.
g / cm ² , and an air flow rate of 1800 cc / cm ² · min. at an air pressure of 0.01 kg / cm ² . A sound insulating structure (16) was produced in exactly the same manner as in Example 1, except that

(Example 17) The low-density layer had an area density of 200
0 g / cm^Two, Air flow rate 0.01kg / cm ^TwoTo
1600cc / cm^Two-Min. Other than
A sound insulation structure (17) was produced in exactly the same manner as in Example 1.
Was.

(Example 18) The low-density layer had a thickness of 15 m.
m, the ventilation rate is 15 at an air pressure of 0.01 kg / cm ² .
50 cc / cm ² · min. A sound insulating structure (18) was produced in exactly the same manner as in Example 1, except that

(Example 19) The thickness of the low-density layer was set to 50 m.
m, the ventilation rate is 18 at an air pressure of 0.01 kg / cm ² .
00 cc / cm ² · min. A sound insulation structure (19) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

Example 20 The low-density layer had a fiber diameter of 10 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 14 μm and a fiber length of 50 mm, softened from fiber C
The polyester fiber B whose point is 90 ° C lower is composed of 10% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
1650cc / cm^Two-Min. Example 1 except that
A sound-insulating structure (20) was produced in exactly the same manner as described above.

Example 21 The low-density layer had a fiber diameter of 40 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 14 μm and a fiber length of 50 mm, softened from fiber C
The polyester fiber B whose point is 90 ° C lower is composed of 10% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
1900cc / cm^Two-Min. Example 1 except that
A sound insulation structure (21) was produced in exactly the same manner as in (1).

Example 22 The low-density layer had a fiber diameter of 25 μm.
m, 90% by weight of polyester fiber C having a fiber length of 100 mm, and 10% by weight of polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm and a softening point of 90 ° C. lower than that of fiber C. in the ^{01kg / cm 2 1900cc / cm 2} · min. A sound insulation structure (22) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

Example 23 The low-density layer had a fiber diameter of 25 μm.
m, 70% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 14 μm and a fiber length of 50 mm, softened from fiber C
30% by weight of polyester fiber B whose point is lower by 90 ° C.
Air flow rate is 0.01kg / cm ^TwoAt
1950cc / cm^Two-Min. Example 1 except that
A sound-insulating structure (23) was produced in exactly the same manner as described above.

Example 24 The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 10 μm and a fiber length of 50 mm, softened from fiber C
The polyester fiber B whose point is 90 ° C lower is composed of 10% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
1650cc / cm^Two-Min. Example 1 except that
A sound insulation structure (24) was produced in exactly the same manner as in (1).

Example 25 The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 20 μm and a fiber length of 50 mm, softened from fiber C
The polyester fiber B whose point is 90 ° C lower is composed of 10% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
1850cc / cm^Two-Min. Example 1 except that
A sound insulation structure (25) was produced in exactly the same manner as in (1).

Example 26 The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 14 μm and a fiber length of 30 mm, softened from fiber C
The polyester fiber B whose point is 90 ° C lower is composed of 10% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
1750cc / cm^Two-Min. Example 1 except that
A sound insulation structure (26) was produced in exactly the same manner as in (1).

(Example 27) The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
And 10% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 100 mm, and a softening point lower than that of the fiber C by 90 ° C., and a ventilation rate of 1900 cc / cm ² · min. At an air pressure of 0.01 kg / cm ² . A sound insulation structure (27) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

(Example 28) The difference between the softening points of the polyester fibers A and B forming the high-density layer was 20.
° C, the ventilation rate is 1 at an air pressure of 0.01 kg / cm ² .
200 cc / cm ² · min. A sound insulation structure (28) was produced in exactly the same manner as in Example 1, except that

(Example 29) The difference between the softening points of the polyester fibers C and B forming the low-density layer was 20.
° C, the ventilation rate is 1 at an air pressure of 0.01 kg / cm ² .
850 cc / cm ² · min. A sound insulation structure (29) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

Example 30 The low-density layer had a fiber diameter of 25 μm.
m, 90% by weight of polyester fiber C having a fiber length of 30 mm
With a fiber diameter of 14 μm and a fiber length of 50 mm, softened from fiber C
The polyester fiber B whose point is 90 ° C lower is composed of 10% by weight.
Air flow rate is 0.01kg / cm ^Two・ Mi
n. At 1650cc / cm^Two-Min. Because
Outside, a sound insulation structure (30) was made in exactly the same manner as in Example 1.
Made.

Comparative Example 1 The high-density layer had an area density of 50 g /
cm ² and an air flow rate of 1300 cc / cm ² · min. at an air pressure of 0.01 kg / cm ² . Example 1 except that
A sound-insulating structure (31) was produced in exactly the same manner as described above.

(Comparative Example 2) The area density of the high-density layer was 2000
g / cm^Two, Air flow rate 0.01kg / cm ^TwoIn
And 400cc / cm^Two-Min. Example except for
A sound insulation structure (32) was produced in exactly the same manner as in Example 1.

(Comparative Example 3) A sound insulating structure (33) was produced in exactly the same manner as in Example 1 except that the thickness of the high-density layer was formed to 1 mm or less. And could not be produced.

(Comparative Example 4) The thickness of the high-density layer was 20 mm,
The air flow rate is 1200 at an air pressure of 0.01 kg / cm ² .
cc / cm ² · min. A sound insulating structure (34) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

(Comparative Example 5) The high-density layer had a fiber diameter of 5 µm,
50% by weight of a polyester fiber A having a fiber length of 50 mm,
Except that the fiber diameter is 14 μm, the fiber length is 50 mm, and the softening point is 90 ° C. lower than that of the fiber A, the polyester fiber B is composed of 50% by weight.
An attempt was made to produce 5), but the fiber A was too thin to form a nonwoven fabric and could not be produced.

Comparative Example 6 The high-density layer had a fiber diameter of 40 μm,
50% by weight of a polyester fiber A having a fiber length of 50 mm,
It is composed of 50% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm and a softening point lower than that of the fiber A by 90 ° C., and a ventilation volume of 14 kg at an air pressure of 0.01 kg / cm ² .
00 cc / cm ² · min. A sound insulation structure (36) was produced in exactly the same manner as in Example 1 except for the following.

Comparative Example 7 The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 30 mm
A sound insulation structure (37) was produced in exactly the same manner as in Example 1, except that the fiber diameter was 14 μm, the fiber length was 50 mm, and the softening point was 90 ° C. lower than that of the fiber A. However, the fiber A was too short to be a non-woven fabric and could not be produced.

Comparative Example 8 The high-density layer had a fiber diameter of 14 μm.
m, 50% by weight of a polyester fiber A having a fiber length of 200 mm, and 50% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm and a softening point of 90 ° C. lower than that of the fiber A. in the ^{01kg / cm 2 1300cc / cm 2} · min. A sound insulation structure (38) was produced in exactly the same manner as in Example 1 except for the following.

Comparative Example 9 The high-density layer had a fiber diameter of 14 μm.
m, and the sound insulation structure (3
9) was attempted, but the high-density layer could not be formed sufficiently thin with only the fiber A, and the thickness of the sound insulating structure (39) could not be reduced to 60 mm or less.

Comparative Example 10 The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 50 mm
And a 50% by weight polyester fiber B having a fiber diameter of 5 μm, a fiber length of 50 mm and a softening point 90 ° C. lower than that of the fiber A, and the weight of the sound insulating structure (4
0) was attempted, but the fiber B was too thin to form a non-woven fabric and could not be produced.

Comparative Example 11 The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 50 mm
With a fiber diameter of 40 μm and a fiber length of 50 mm, softened from fiber A
The polyester fiber B whose point is lower by 90 ° C. is composed of 50% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
1400cc / cm^Two-Min. Example 1 except that
A sound insulation structure (41) was produced in exactly the same manner as in the above.

(Comparative Example 12) The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 50 mm
A sound insulation structure (42) was produced in exactly the same manner as in Example 1 except that the fiber diameter was 14 μm, the fiber length was 15 mm, and the softening point was 90 ° C. lower than that of the fiber A. However, the fiber B was too short to be made into a nonwoven fabric and could not be produced.

(Comparative Example 13) The high-density layer had a fiber diameter of 14 μm.
50% by weight of polyester fiber A having a fiber length of 50 mm
And 50% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 200 mm and a softening point lower than that of the fiber A by 90 ° C., and a ventilation rate of 1300 cc / cm ² · min. At an air pressure of 0.01 kg / cm ² . A sound insulation structure (43) was produced in exactly the same manner as in Example 1 except for the following.

(Comparative Example 14) The low-density layer had an area density of 200
g / cm ² , and an air flow rate of 1900 cc / cm ² · min. at an air pressure of 0.01 kg / cm ² . A sound insulation structure (44) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were satisfied.

(Comparative Example 15) The low-density layer had an area density of 300
0 g / cm^Two, Air flow rate 0.01kg / cm ^TwoTo
1200 cc / cm^Two-Min. Other than
A sound insulation structure (45) was produced in exactly the same manner as in Example 1.
Was.

(Comparative Example 16) The low-density layer had a thickness of 10 m.
m, the ventilation rate is 12 at an air pressure of 0.01 kg / cm ² .
00 cc / cm ² · min. A sound insulation structure (46) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

(Comparative Example 17) The thickness of the low density layer was 100 m
An attempt was made to produce the sound insulation structure (47) in exactly the same manner as in Example 1 except that the size was changed to m, but the size did not become a realistic size in practical use.

(Comparative Example 18) The low-density layer had a fiber diameter of 5 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
And a 10% by weight polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm, and a softening point 90 ° C. lower than that of the fiber C, and the sound insulation structure (48) was produced in exactly the same manner as in Example 1. However, the fiber C was too thin to be formed into a non-woven fabric and could not be produced.

Comparative Example 19 The low-density layer had a fiber diameter of 60 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 14 μm and a fiber length of 50 mm, softened from fiber C
The polyester fiber B whose point is 90 ° C lower is composed of 10% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
2150cc / cm^Two-Min. Example 1 except that
A sound insulation structure (49) was produced in exactly the same manner as in (1).

Comparative Example 20 The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 20 mm
A sound insulation structure (50) was produced in the same manner as in Example 1 except that the fiber diameter was 14 μm, the fiber length was 50 mm, and the softening point was 90 ° C. lower than that of the fiber C. However, the fiber C was so short that it did not become a nonwoven fabric and could not be produced.

(Comparative Example 21) The low-density layer had a fiber diameter of 25 μm.
m, 90% by weight of a polyester fiber C having a fiber length of 200 mm, and 10% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of 50 mm and a softening point lower by 90 ° C. than the fiber C by 10% by weight. in the ^{01kg / cm 2 2050cc / cm 2} · min. A sound insulation structure (51) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

Comparative Example 22 The low-density layer had a fiber diameter of 25 μm.
50% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 14 μm and a fiber length of 50 mm, softened from fiber C
The polyester fiber B whose point is lower by 90 ° C. is composed of 50% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
2100cc / cm^Two-Min. Example 1 except that
A sound insulation structure (52) was produced in exactly the same manner as in (1).

(Comparative Example 23) The low-density layer had a fiber diameter of 25 μm.
m, the sound insulation structure (5
Although 3) was attempted, the thickness of the low-density layer could not be sufficiently suppressed only by the fiber C, and the thickness of the sound insulating structure (53) could not be reduced to 60 mm or less.

(Comparative Example 24) The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
And 10% by weight of a polyester fiber B having a fiber diameter of 5 μm, a fiber length of 50 mm and a softening point 90 ° C. lower than that of the fiber C, and the sound insulating structure (5
An attempt was made to produce 4), but the fiber B was too thin to form a non-woven fabric and could not be produced.

(Comparative Example 25) The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
With a fiber diameter of 40 μm and a fiber length of 50 mm, softened from fiber C
The polyester fiber B whose point is 90 ° C lower is composed of 10% by weight.
Air flow rate is 0.01kg / cm ^TwoAt
2050cc / cm^Two-Min. Example 1 except that
A sound insulation structure (55) was produced in exactly the same manner as described above.

Comparative Example 26 The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
A sound insulating structure (56) was produced in exactly the same manner as in Example 1, except that the fiber diameter was 14 μm, the fiber length was 15 mm, and the softening point was 90 ° C. lower than that of the fiber C by 10% by weight. However, the fiber B was so short that it did not become a nonwoven fabric and could not be produced.

(Comparative Example 27) The low-density layer had a fiber diameter of 25 μm.
90% by weight of polyester fiber C having a fiber length of 50 mm
When the fiber diameter 14 [mu] m, a softening point from fiber C with a fiber length 200mm is composed of 10 wt% to 90 ° C. lower polyester fiber B, 2100cc / cm ² · min airflow rate at pressure 0.01 kg / cm ^2. A sound insulation structure (57) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

(Comparative Example 28) The difference in softening point between the polyester fibers A and B forming the high-density layer was 10
° C, the ventilation rate is 1 at an air pressure of 0.01 kg / cm ² .
350 cc / cm ² · min. A sound insulation structure (58) was produced in exactly the same manner as in Example 1, except that

(Comparative Example 29) The difference in softening point between the polyester fiber C and the polyester fiber B forming the low density layer was 10
° C, the ventilation rate is ² at an air pressure of 0.01 kg / cm ² .
100 cc / cm ² · min. A sound insulation structure (59) was produced in exactly the same manner as in Example 1 except that the above-mentioned conditions were adopted.

Tables 1, 2, 3 and 4 show the test results of the structures and characteristic values of the samples obtained by the above Examples and Comparative Examples.

[0110]

[Table 1]

[0111]

[Table 2]

[0112]

[Table 3]

[0113]

[Table 4]

In the results shown in the above table, it was determined that a sound transmission loss difference of less than 1 dB in any of the frequency ranges of 300 to 500 Hz and 500 Hz to 1 kHz had no effect.

From these tables, it can be seen that each of the sound insulation structures of the present invention produced in the examples has a lower frequency than the sound insulation level based on the mass rule of sound transmission loss (TL) determined by the mass of the entire laminated structure. It was confirmed that the sound insulation performance in the region was improved. Moreover, the comparative example which does not correspond to the present invention could not obtain a satisfactory value for the sound insulation performance.

[0116]

As described above, the sound-insulating structure of the present invention can control the air permeability of the high-density layer, and has a lower frequency range than the conventional sound-insulating structure having a high-density layer having no air permeability. This has the effect of significantly improving the sound insulation performance of the device.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a floor insulator mounted on a vehicle.

FIG. 2 is a vertical sectional view of a floor insulator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Floor panel 2 Sound insulation structure 3 Low density layer 4 High density layer 5 Floor carpet

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI E04B 1/86 G10K 11/16 D G10K 11/162 A (72) Inventor Kyoichi Watanabe 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan (72) Inventor Yoshikazu Nemoto 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Nissan Motor Co., Ltd. (56) References JP-A-10-236206 (JP, A) JP-A-8-152890 ( JP, A) JP-A-9-1704 (JP, A) JP-A-49-88701 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G10K 11/16 B32B 5/26 B32B 25/10 B60R 13/08 D04H 1/54 E04B 1/86

Claims (7)

(57) [Claims] 1. A laminate having at least two layers of nonwoven fabrics having different air permeability laminated thereon and having a surface density of 0.5 to 3.0 kg / cm ² and a thickness of 16 to 60 mm,
The difference in air flow between the layers is 450 to 1000 cc / cm ² · min. At an air pressure of 0.01 kg / cm ² . A sound insulation structure characterized by the following. 2. In the laminate, the density ratio of each nonwoven fabric layer is in the range of 2/1 to 100/1, and the layer having low air permeability is made of fibers having a fiber diameter of 10 to 25 μm and 0.1 to 0.1 μm.
A high-density layer having an area density of 1.0 kg / cm ² and a thickness of 1 to 10 mm, and a layer having a high air permeability has a fiber diameter of 10
0.4 to 2.0 kg / cm
^2. The sound insulation structure according to claim 1, wherein the sound insulation structure is a low-density layer having a surface density of ² and a thickness of 15 to 50 mm. 3. The non-woven fabric according to claim 1, wherein the high-density layer is made of short fibers mainly composed of polyester, and has a fiber diameter of 10 to 25 μm.
Consisting of at most 80% by weight of fiber A having a fiber length of 30 to 100 mm, and at least 20% by weight of fiber B having a softening point at least 20 ° C. lower than the softening point of fiber A and having a diameter of 10 to 20 μm and a fiber length of 30 to 100 mm. 700 to 1250 c at an air pressure of 0.01 kg / cm ²
c / cm ² · min. 3. The method according to claim 2, wherein
The sound insulation structure according to any one of the preceding claims. 4. The non-woven fabric, wherein the low-density layer is made of short fibers mainly composed of polyester, and has a fiber diameter of 10 to 40 μm.
A fiber C having a fiber length of 30 to 100 mm and 70 to 90% by weight;
The fiber C has a softening point at least 20 ° C. lower than that of the fiber C, a fiber diameter of 10 to 20 μm, a fiber length of 30 to 100 mm, and a fiber B of 10 to 30% by weight, and an air flow rate of 0.01 kg / cm ² . 1700-1950
cc / cm ² · min. The sound insulation structure according to any one of claims 2 to 3, wherein 5. A double-walled sound insulation structure in which the at least one high-density layer is formed together with the external partition through at least one low-density layer by attaching the laminate to an external partition; The primary resonance frequency of the double wall sound insulation structure is 50 to 3
The sound insulation structure according to any one of claims 2 to 4, wherein the frequency is set to a frequency in a range of 00Hz. 6. The double-walled sound insulation structure has a frequency average of 1 to 300 Hz to 1 kHz in a frequency range of 300 Hz to 1 kHz with respect to a sound insulation level according to a mass law of sound transmission loss (TL) determined by the mass of the whole laminate. 6. The sound insulation structure according to claim 5, wherein the sound insulation structure exhibits a sound transmission loss (TL) improved by ~ 3 dB. 7. The floor insulator of an automobile, wherein the double-walled sound insulation structure is formed on the vehicle interior side, and is applied as an automobile floor insulator with a carpet installed on the laminate. The sound insulation structure according to claim 5, wherein: