JP3538293B2 - 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 sound insulation structure which can be used for floor insulators for automobiles and the like, and particularly to forming a high airflow resistance layer in order to improve sound insulation performance in a low frequency region. The present invention relates to a sound insulation structure in which the air permeability is controlled by the above.

[0002]

2. Description of the Related Art As shown in FIG. 1, a sound insulation structure 2 in a floor insulator for an automobile is located on the interior side of a floor panel 1 which partitions the interior of the automobile from the outside, and transmits noise from outside to the interior of the automobile. Has a role to prevent. As shown in FIG. 1, the sound insulating structure 2 includes a low-density layer 3 made of a porous base material such as felt, polyurethane foam, and nonwoven fabric.
It is composed of a laminated structure of a high density layer 4 having no air permeability, such as an EVA material sheet or a polyethylene sheet mixed with a filler. The low-density layer 3 absorbs noise from outside the vehicle, and the double-walled sound insulation structure of the floor panel 1 and the high-density layer 4 provides good soundproofing performance in addition to the sound insulation effect. It is configured. As described above, in the conventional sound insulation structure for floors, the high-density layer 4 and the floor panel 1 constitute a double-wall sound insulation structure, thereby ensuring sound insulation performance.

[0003]

However, since the high-density layer 4 does not have air permeability, it has excellent sound insulation performance in a high frequency range, but in a low frequency range that is important for the sound insulation performance of floor components. Performance degradation 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 to the sound insulation level is small.

Accordingly, 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, a high air permeability is obtained by mechanically and / or thermally treating the surface. It is an object of the present invention to provide a sound insulation structure in which the performance near a resonance point is improved by forming a resistance layer to control the air permeability, thereby improving the sound insulation performance in a low frequency range.

[0005]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
A fiber assembly composed of short fibers mainly composed of polyester, having a fiber diameter of 10 to 40 μm and a fiber length of 30 to
100mm round section fiber or irregular section fiber (fiber A)
Is 70 to 90% by weight and at least 20 ° C.
Is a fiber having a low softening point, a fiber diameter of 10 to 20 μm,
Fiber with a fiber length of 30 to 100 mm (fiber B) is 10 to 30
% And an areal density of 0.5 to 3.0 kg /
m ² , a fiber aggregate having a thickness of 16 to 60 mm, wherein at least one high airflow resistance layer is formed in the fiber aggregate by mechanically and / or thermally treating the surface layer of the fiber aggregate. And the difference in air permeability between the formed high airflow resistance layer and the other layers is 400 to 400 kg / cm ² at an air pressure of 0.01 kg / cm ² .
This has been achieved by a sound insulation structure characterized by being in the range of 1400 cc / cm ² · min.

[0006] In the present invention, the difference in air flow rate is 400 to 1400 cc / cm ² at an air pressure of 0.01 kg / cm ² for each layer.
It must be within the range of ² · min. To ensure the performance as a sound insulation structure, an external partition and 2
In order to form a heavy wall structure, at least one
The high airflow resistance layer must be formed, the airflow resistance of the high airflow resistance layer must be sufficiently ensured, and the difference in airflow between the high airflow resistance layer and other fiber aggregates must be within the above range.

To form the high airflow resistance layer, there are a method of strengthening the entanglement of the fibers by a mechanical treatment and a method of strengthening the bonding of the fibers by a thermal treatment. In addition, by performing the mechanical processing and the thermal processing at the same time, it is possible to more precisely control the air flow rate.

[0008] When the difference in air flow rate is less than 400 cc / cm ² · min, the structure becomes the same as the single-layer structure, and the double-wall structure is not formed. Conversely, the difference in air flow is 1400 cc / cm ²
If it exceeds min, the desired sound insulation performance in the low frequency range cannot be achieved.

The surface density of the entire structure is 0.5 to 3.0 k.
g / m ² . In order to ensure sound insulation performance, the higher the surface density of the structure, the better, but 3.0 k
If it exceeds g / m ² , it is unfavorably too heavy for practical use. Conversely, if the areal density is less than 0.5 kg / m ² , the purpose of sound insulation performance cannot be achieved.

The thickness of the entire structure needs to be in the range of 16 to 60 mm. If the thickness is less than 16 mm, sufficient sound insulation performance cannot be obtained with the surface density in the above range.
On the other hand, to improve the sound absorption performance, the thicker the better, the better.
When the thickness exceeds mm, it is not preferable from the viewpoint of securing a space in actual use.

The fibers constituting the structure can be appropriately selected from known synthetic fibers and used. Specific examples thereof include, for example, polyester, nylon, polyacrylonitrile, polyacetate, polyethylene, polypropylene, flocculent polyester, polyamide and the like, and are particularly suitable from the viewpoint of flowability and mechanical strength.
Polyester having high cost performance is preferable.

Next, the high airflow resistance layer will be described. In order to improve the sound insulation performance of the sound insulation structure of the present invention, a high air resistance layer is formed to reduce air permeability, and a double wall sound insulation structure is formed by the high air resistance layer and the outer partition. Is required.

The first is the effect of air permeability. To improve the sound insulation performance, it is better to reduce the air flow rate. The air permeability is caused by various factors such as the surface density, the fiber diameter, and the fiber cross-sectional shape of the fiber material layer. It is very effective in reducing air permeability. However, an increase in density results in an increase in overall weight and material costs.

Second, regarding the effect of the formation of the double-walled sound insulation structure with the external partition, if the external partition and the high ventilation resistance layer form a double wall, the effect of improving the sound insulation performance will be increased. Although it is possible to form a double wall by increasing the weight, it is not preferable to increase the weight, and the physical properties such as air permeability and rigidity are controlled by operations such as fiber blending and surface density to form the double wall. It is necessary.

In consideration of the above description, in order to improve the sound insulation performance of the sound insulation structure of the present invention, the ventilation resistance of the fiber assembly is controlled by forming a high ventilation resistance layer.
Ideally, an outer partition and a double-wall sound insulation structure are formed.

The performance of the airflow resistance changes depending on the fiber diameter, area density and thickness. The smaller the fiber diameter, that is, the larger the surface area in the fiber aggregate, the higher the airflow resistance. However, fine fibers are expensive and difficult to form into a non-woven fabric, and thus it is not preferable to use fine fibers having a fiber diameter of less than 10 μm from the viewpoint of economy and moldability. On the other hand, 40μ
If it exceeds m, sufficient airflow resistance cannot be obtained, and the object of the present invention of improving sound insulation performance cannot be achieved.

Next, other layers (hereinafter, referred to as a low airflow resistance layer) in the sound insulation structure except the high airflow resistance layer will be described. In order to improve the sound insulation performance of the sound insulation structure of the present invention, controlling the air permeability of the low airflow resistance layer, reducing the vibration transmissibility,
It is necessary to improve the sound absorption coefficient.

First, regarding the effect of the vibration transmissibility of the low airflow resistance layer, as the vibration transmissivity decreases, the sound insulation performance improves. Here, the vibration transmissibility greatly depends on the dynamic spring constant of the object, and it is necessary to reduce the dynamic spring constant to improve the sound insulation performance.

Second, regarding the effect of the sound absorption coefficient of the low airflow resistance layer, the higher the sound absorption coefficient, the better the sound insulation performance. The sound absorption coefficient is determined due to various factors such as the surface density of the fiber material layer, the fiber diameter, and the fiber cross-sectional shape. Doing so is very effective in improving the sound absorption coefficient. But,
An increase in density leads to an increase in overall weight and also to a higher material cost.

In consideration of the above description, in order to improve the sound insulation performance of the sound insulation structure of the present invention, the airflow resistance of the fiber assembly which is to be a low airflow resistance layer is controlled, the spring constant is reduced, and the sound absorption coefficient is reduced. It would be ideal to improve it.

As described in the description of the high airflow resistance layer, the performance of the airflow resistance changes depending on the fiber diameter, the surface density, and the thickness. Further, the sound absorbing performance and the spring constant vary in performance depending on the fiber diameter. The airflow resistance increases as the fiber diameter decreases, that is, as the surface area in the fiber aggregate increases. At the same time, the smaller the fiber diameter, the better the sound absorbing performance. Therefore, the smaller the fiber diameter, the better. However, since the fine fiber is expensive, the cost is increased, and the moldability into a nonwoven fabric is inferior. On the other hand, if it exceeds 40 μm, the airflow resistance and the sound absorption performance are significantly reduced at the same time, and the object of the present invention of improving the sound insulation performance cannot be achieved.

Next, the fiber composition of the sound insulating structure of the present invention will be described. The sound-insulating structure of the present invention is a fiber aggregate composed of short fibers mainly composed of polyester, and has a fiber cross section or a modified cross section fiber (fiber A) having a fiber diameter of 10 to 40 μm and a fiber length of 30 to 100 mm. Is 70-90
% By weight and a fiber having a softening point lower by at least 20 ° C. than the above-mentioned fiber, having a fiber diameter of 10 to 20 μm and a fiber length of 30.
Fiber of 100 mm to 100 mm (fiber B) is 10 to 30% by weight.

The fiber A is a short fiber mainly composed of polyester and has a fiber diameter of 10 to 40 μm and a fiber length of 30 to 100 mm.
70 to 9 composed of round cross-section fibers or irregular cross-section fibers
0% by weight is blended. This is to increase the surface area in the fiber aggregate by blending fine denier fiber,
This is because it is necessary to improve the ventilation resistance. This makes it possible to form a double-wall sound insulation structure.
In addition, with respect to the fiber length and the cross-sectional shape, the short fiber and the irregular cross section further increase the airflow resistance. Further, there is an object of not only controlling the air permeability but also reducing the vibration transmission rate and improving the sound absorption rate.

As described above, in order to improve the sound insulation performance and reduce the amount of ventilation, it is desirable to incorporate a large number of fine fibers. However, as a result, the shape maintainability is reduced, and sag occurs to make it impossible to secure the thickness necessary to satisfy the required performance. Therefore, it is necessary to mix relatively thick fibers. For this reason, in the present invention, the fiber diameter needs to be in the range of 10 to 40 μm. If the fiber diameter exceeds 40 μm, sufficient airflow resistance cannot be obtained, and it becomes difficult to obtain good sound insulation performance. On the other hand, when the fiber diameter is less than 10 μm, it is difficult to manufacture the fiber, it is difficult to stably supply the fiber, and the cost is increased. Moreover, it becomes difficult to mix with other fibers B, and it becomes difficult to obtain a uniform fiber aggregate.

It is necessary that the amount of the fiber A is in the range of 70 to 90% by weight. If the amount exceeds 90% by weight, it is difficult to form a sound absorbing material, and a sufficient density cannot be secured, so that the object of the present invention cannot be achieved. Conversely, if it is less than 70% by weight, it is not suitable for obtaining sufficient airflow resistance.

The fiber B is a fiber having a fiber diameter of 10 to 20 μm and a fiber length of 30 to 100 mm, and has a softening point lower than that of the fiber A by at least 20 ° C. (hereinafter, referred to as a binder fiber). In a proportion of

This means that some blending of fibers capable of providing moldability is required. The sound insulation structure of the present invention,
Adhesion to parts where sound insulation is required is a major factor for improving performance, and it is necessary that the fiber aggregate can be formed so as to follow the surface shape. The followability is improved by using the above-mentioned short fibers, but in order to maintain the shape, it is necessary to add a binder fiber. At the time of heat molding, the binder fiber is softened and adhered in a state where the fiber A is constrained in the shape of the mold, so that a fine surface shape can be maintained.

The fiber diameter of the binder fiber is 10 to 20 μm.
Must be within the range. When the fiber diameter is less than 10 μm, it is not general, the cost is high, and the binder fiber itself is sagged at the time of heat molding,
Further, it is difficult to mix with the fiber A, and it is difficult to obtain a uniform fiber aggregate. Conversely, if the fiber diameter exceeds 20 μm,
Since the number of fibers is relatively reduced, the number of bonding points with other fibers is reduced, and it is difficult to maintain the shape.

Further, it is necessary that the difference in the softening point of the fibers themselves required for producing a product by heating and press-forming while maintaining the shape of the fiber aggregate differs by at least 20 ° C. If the difference in softening point is smaller than this, the entire fibrous body will be softened.

It is necessary that the amount of the fiber B is 10 to 30% by weight from the viewpoint of ensuring formability and density. If the amount is less than 10% by weight, molding becomes difficult. Conversely, if it exceeds 30% by weight, it is not suitable for obtaining sufficient airflow resistance.

Fibers A and B constituting the sound insulating structure of the present invention
In both cases, the fiber length needs to be in the range of 30 to 100 mm. The fiber length of the fibers A and B needs to be within the above range from the viewpoint of the effect on the surface area in the fiber assembly and the improvement of the mechanical strength of the fiber assembly. A fiber having a fiber length of less than 30 mm is inferior in productivity of a nonwoven fabric, and a fiber having a fiber length of more than 100 mm is difficult to disperse evenly in a fiber aggregate, and is a material sufficient for seeking high-quality stability. No.

Next, a method for forming the high airflow resistance layer will be described. As a method of forming the high airflow resistance layer, there is a method of performing mechanical and / or thermal treatment on the surface layer portion of the fiber assembly.

As the mechanical treatment, there is a needle punching treatment, which makes it possible to strengthen the entanglement of the fibers. Needle punching is a general method in the production of nonwoven fabric, is not special in terms of equipment, and can form an arbitrary high airflow resistance layer by setting processing conditions.

At this time, the thickness of the high airflow resistance layer is 1 to 10 m.
m. If the thickness is less than 1 mm, it is difficult to manufacture, and if it exceeds 10 mm, the low airflow resistance layer cannot have a sufficient thickness and the sound insulation performance cannot be satisfied.

The difference in air permeability between the formed high airflow resistance layer and the other layers is 400 to 400 at an air pressure of 0.01 kg / cm ² .
It must be within the range of 1400 cc / cm ² · min. When the difference in the air flow rate is less than 400 cc / cm ² · min, the structure becomes the same as the single-layer structure, and the double-wall structure is not formed. Ventilation difference is 1400cc / cm ² · min
When it exceeds, the target of the sound insulation performance cannot be achieved.

As the thermal treatment, there is a heat treatment for the surface layer, which promotes the melting of the binder fiber and increases the number of bonding points between the fibers. The heat treatment is generally performed in the production of nonwoven fabric, is not special in terms of equipment, and can form an arbitrary high airflow resistance layer by setting temperature conditions.

At this time, the thickness of the high airflow resistance layer is also the same as above, and needs to be within the range of 1 to 10 mm. If the thickness is less than 1 mm, it is difficult to manufacture, and if it exceeds 10 mm, the low airflow resistance layer cannot secure a sufficient thickness and the sound insulation performance cannot be satisfied.

The difference in air permeability between the formed high airflow resistance layer and the other layers is 400 to 400 kg / cm ² at an air pressure of 0.01 kg / cm ² .
It must be within the range of 1400 cc / cm ² · min. When the difference in the air flow rate is less than 400 cc / cm ² · min, the structure becomes the same as the single-layer structure, and the double-wall structure is not formed. Conversely, the difference in ventilation rate is 1400cc / cm ²
If it exceeds min, the target of the sound insulation performance in the low frequency range cannot be achieved.

The thermal treatment also includes an embossing treatment on the surface layer, which locally promotes the melting of the binder fibers in the surface layer to increase the number of bonding points between the fibers. The embossing process is not special in terms of equipment, and it is possible to form an arbitrary high airflow resistance layer by setting processing conditions.

At this time, the thickness of the high airflow resistance layer is also 1 to 10
mm. When the thickness is less than 1 mm, it is difficult to manufacture, and when the thickness exceeds 10 mm,
The low airflow resistance layer cannot secure a sufficient thickness and the sound insulation performance cannot be satisfied.

The difference in air permeability between the formed high air resistance layer and the other layers is 400 to 400 kg / cm ² at an air pressure of 0.01 kg / cm ² .
It must be within the range of 1400 cc / cm ² · min. When the difference in the air flow rate is less than 400 cc / cm ² · min, the structure becomes the same as the single-layer structure, and the double-wall structure is not formed. Conversely, the difference in ventilation rate is 1400cc / cm ²
If it exceeds min, the target of the sound insulation performance in the low frequency range cannot be achieved.

Although there are three methods for forming the high airflow resistance layer as described above, the airflow resistance can be controlled more precisely by performing them simultaneously, but there is no particular limitation.

Next, control of the resonance frequency will be described. By installing the sound insulation structure of the present invention on the partition,
A double-walled sound insulation structure is formed by at least one layer of the high airflow resistance layer and the outer partition in the fiber assembly, and the fiber composition, air permeability, rigidity, elastic modulus, and low density layer of the high airflow resistance layer (1) ( The primary resonance frequency is adjusted to 50 to 300 Hz by manipulating the fiber composition, thickness, dynamic spring constant, and air permeability of 2).
Can be set to any frequency.

In order to improve the sound insulation performance, it is necessary to form a double-walled sound insulation structure by using the sound insulation structure and an external partition. However, as a characteristic of the double-wall sound insulation structure,
A resonance phenomenon occurs at a certain frequency on the sound insulation performance curve. Therefore, by shifting this resonance point to the 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. According to the present invention, the resonance point can be set arbitrarily, and the sound insulation performance is improved.

The primary resonance frequency of a double-walled sound insulation structure having a porous material inserted therein is generally approximated by equation (1). f = 1 / 2π · (k / m) ^1/2 ‥‥ (1) m is the areal density of the high airflow resistance layer, and k is the spring constant of the low airflow resistance layer.

However, since the double-walled sound insulating structure of 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 of setting the resonance point arbitrarily, in order to set a low frequency, the fiber composition of the high airflow resistance layer is manipulated, the airflow is reduced, the rigidity and elastic modulus are improved, and the low airflow resistance is set. Effective methods include manipulating the fiber composition of the layers, increasing the thickness, and reducing the dynamic spring constant and ventilation. Performing all of these at the same time enables a more precise resonance point setting operation, but is not particularly limited.

In the sound insulation structure of the present invention, it is necessary to set the primary resonance frequency to a frequency in the range of 50 to 300 Hz. If the resonance point is set to a frequency of 300 Hz or more, the sound insulation performance is reduced in a low frequency region of 1 kHz or less, and the object of the present invention cannot be achieved. On the other hand, setting the resonance point at less than 50 Hz is not preferable because the density increase in the above operation increases, which leads to an increase in weight.

Next, comparison of sound insulation performance with the mass rule will be described. In the double-walled sound-insulating structure, the double-walled sound-insulating structure formed by the sound-insulating structure has a sound transmission loss (TL) determined by the mass of the entire sound-insulating structure, which is equal to 300. In a frequency range of 透過 1 kHz, the sound transmission loss is improved by 1 to 3 dB on the average of the frequency.

In determining the sound insulation performance, one of the factors is the mass of the entire sound insulation structure. 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 sound insulation structure forms a double wall sound insulation structure with the outer partition, as described above, the sound insulation performance falls below the mass law in the resonance region, but exceeds the mass law in the other amount regions. Therefore, it is possible to improve the sound insulation performance in an arbitrary frequency range by forming a double-wall sound insulation structure and operating the resonance point as described above. By using the above-mentioned means, the laminated structure can be 300 to 1 kHz.
In the frequency range of z, it is possible to exceed the sound insulation level of the mass law of sound transmission loss (TL) by 1 to 3 dB.

Next, an application to a floor insulator for an automobile will be described. It is important in terms of required performance to ensure sound insulation performance in a low frequency region, particularly 1 kHz or less, for floor parts for automobiles. Therefore, by applying the sound insulation structure of the present invention to an automobile floor insulator, it is possible to improve the sound insulation performance in a low frequency region required for floor components. Furthermore, since the resonance point can be set arbitrarily, it is possible to further improve the sound insulation performance in a low frequency region.

Further, polyester is often used for the carpet skin used for floor insulators for automobiles, and it is possible to manufacture the entire floor insulator with polyester by combining with the sound insulating structure of the present invention. The recyclability of burrs and the like can be improved.

[0052]

Next, an embodiment of the present invention will be described. The sound insulation structure of the present invention has air permeability and improved sound insulation performance in a low frequency region compared to a conventional product having at least one layer having no air permeability and having the same shape and the same weight.

[0053]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 A surface density of 875 g / cm ² and a total thickness of a fiber aggregate of 35 m
80% by weight of a polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm, a fineness of 14 μm, and a fiber length of about 50
20% by weight of a polyester fiber B having a softening point lower than that of the fiber A by about 90 ° C. in a thickness of 20 mm by needle punching.
gcc / cm ² is 900 cc / cm.
² min, low airflow resistance layer airflow is 1700cc / cm
^The sound insulation structure (1) was produced using the fiber assembly of ² min. By installing this on the outer partition,
The next resonance point was set to 200 [Hz].

Embodiment 2 Area density 500g / cm^Two, Air pressure 0.01kg / cm^Two
High airflow resistance layer airflow at 1300cc / cm^Two・ Mi
n, low airflow resistance layer airflow is 2050 cc / cm ^Two・ Mi
Except for n, the sound insulation structure was exactly the same as in Example 1.
(2) was produced.

Embodiment 3 Area density 3000g / cm^Two, Air pressure 0.01kg / cm
^TwoHigh airflow resistance layer airflow at 600cc / cm^Two・ Mi
n, low airflow resistance layer airflow is 1100 cc / cm ^Two・ Mi
Except for n, the sound insulation structure was exactly the same as in Example 1.
(3) was produced.

Example 4 The total thickness of the fiber assembly was 16 mm, and the air pressure was 0.01 kg /.
High air flow resistance layer air permeability of at cm ² is 800 cc / cm ² ·
min, low airflow resistance layer airflow is 1300 cc / cm ² ·
A sound insulating structure (4) was produced in exactly the same manner as in Example 1 except that the time was set to min.

Example 5 The total thickness of the fiber assembly was 60 mm, and the air pressure was 0.01 kg /.
High air flow resistance layer air permeability of at cm ² is 1200 cc / cm ²
· Min, low air flow resistance layer air permeability 1600cc / cm ²
A sound insulating structure (5) was produced in exactly the same manner as in Example 1 except that the value was set to "min".

Example 6 The thickness of the high airflow resistance layer of the fiber assembly was 1 mm, and the air pressure was 0.0
High airflow resistance layer air flow rate of 1100cc at 1kg / cm ²
/ Cm ² · min, low airflow resistance layer airflow 1600cc
A sound insulating structure (6) was produced in exactly the same manner as in Example 1 except that the rate was set to / cm ² · min.

Example 7 The thickness of the high ventilation resistance layer of the fiber assembly was 10 mm, and the air pressure was 0.1 mm.
High airflow resistance layer air flow rate of 700 cc at 01 kg / cm ²
/ Cm ² · min, low airflow resistance layer airflow 1700cc
A sound-insulating structure (7) was produced in exactly the same manner as in Example 1 except that / cm ² · min was used.

Example 8 A polyester fiber A having a fiber diameter of 10 μm and a fiber length of about 50 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high airflow resistance layer at 800cc / cm ² · mi
n, low airflow resistance layer airflow is 1500 cc / cm ² · mi
Except having set n, the sound insulation structure (8) was produced exactly like Example 1.

Example 9 80% by weight of a polyester fiber A having a fiber diameter of 40 μm and a fiber length of about 50 mm, a fiber diameter of 14 μm and a fiber length of about 50 mm
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high airflow resistance layer at 1100cc / cm ² · mi
n, low airflow resistance layer airflow is 1900 cc / cm ² · mi
Except having set it to n, the sound insulation structure (9) was produced exactly like Example 1.

Example 10 Polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 30 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high airflow resistance layer at 800cc / cm ² · mi
n, low airflow resistance layer airflow is 1500 cc / cm ² · mi
Except having set n, the sound insulation structure (10) was produced exactly like Example 1.

Example 11 Polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 100 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 50 m.
20% by weight of a polyester fiber B having a softening point lower than that of the fiber A by about 90 ° C. and an air pressure of 0.01 kg / cm
^The airflow resistance of the high airflow resistance layer at 1 is 1100 cc / cm ² · m
in, low airflow resistance layer airflow is 2000cc / cm ² · m
A sound insulating structure (11) was produced in exactly the same manner as in Example 1 except that the sample was set to in.

Example 12 Polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm was 70% by weight, a fiber diameter of 14 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 30% by weight, and the air pressure is 0.01 kg / cm ²
Flow rate of high airflow resistance layer at 900cc / cm ² · mi
n, low airflow resistance layer airflow is 1600 cc / cm ² · mi
A sound insulating structure (12) was produced in exactly the same manner as in Example 1 except that n was used.

Example 13 90% by weight of a polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm, a fiber diameter of 14 μm and a fiber length of about 50 mm
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is 10% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high airflow resistance layer at 1100cc / cm ² · mi
n, low airflow resistance layer airflow rate is 1800 cc / cm ² · mi
Except having set it to n, the sound insulation structure (13) was produced exactly like Example 1.

Example 14 80% by weight of a polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm, a fiber diameter of 10 μm and a fiber length of about 50 mm
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high airflow resistance layer at 800cc / cm ² · mi
n, low airflow resistance layer airflow is 1600 cc / cm ² · mi
Except having set n, the sound insulation structure (14) was produced exactly like Example 1.

Example 15 A polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm was 80% by weight, a fiber diameter of 20 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
Flow rate of high airflow resistance layer at 900cc / cm ² · mi
n, low airflow resistance layer airflow is 1750 cc / cm ² · mi
Except having set it to n, the sound insulation structure (15) was produced exactly like Example 1.

Example 16 80% by weight of a polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm, a fiber diameter of 14 μm and a fiber length of about 30 mm
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
850cc / cm ² · mi
n, low airflow resistance layer airflow rate is 1550cc / cm ² · mi
Except having set it to n, the sound insulation structure (16) was produced exactly like Example 1.

Example 17 80% by weight of a polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm, a fiber diameter of 14 μm and a fiber length of about 100 m
20% by weight of a polyester fiber B having a softening point lower than that of the fiber A by about 90 ° C. and an air pressure of 0.01 kg / cm
^The airflow rate of the high airflow resistance layer at 10 is 1050 cc / cm ² · m
in, low airflow resistance layer airflow is 1800 cc / cm ² · m
A sound insulating structure (17) was produced in exactly the same manner as in Example 1 except that the sample was set to in.

Example 18 Polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 20 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high airflow resistance layer at 800cc / cm ² · mi
n, low airflow resistance layer airflow is 1400 cc / cm ² · mi
Except having set n, the sound insulation structure (18) was produced exactly like Example 1.

Example 19 Instead of the needle punching treatment, a part of the surface layer was melted by heat treatment to form a high airflow resistance layer.
A sound insulation structure (19) was produced in exactly the same manner as in Example 1.

Example 20 Instead of needle punching, embossing was performed.
Except that part of the surface layer was densified to form a high airflow resistance layer, the sound insulation structure (20) was exactly the same as in Example 1.
Was prepared.

Comparative Example 1 Area density 300g / cm^Two, Air pressure 0.01kg / cm^Two
Resistance of the high airflow resistance layer is 1400cc / cm^Two・ Mi
n, low airflow resistance layer airflow is 2900 cc / cm ^Two・ Mi
Except for n, the sound insulation structure was exactly the same as in Example 1.
(21) was produced.

Comparative Example 2 Area density 5000 g / cm ² , air pressure 0.01 kg / cm
High air flow resistance layer aeration at ² 250 cc / cm ² · mi
n, low airflow resistance layer air flow rate is 800 cc / cm ² · min
A sound insulation structure (22) was produced in exactly the same manner as in Example 1 except that the above-mentioned was used.

Comparative Example 3 The total thickness of the fiber assembly was 10 mm, and the air pressure was 0.01 kg /
High air flow resistance layer air permeability of at cm ² is 900 cc / cm ² ·
min, low airflow resistance layer airflow is 1150 cc / cm ² ·
A sound insulating structure (23) was produced in exactly the same manner as in Example 1 except that the value was set to min.

Comparative Example 4 An attempt was made to produce a sound insulating structure (24) in exactly the same manner as in Example 1 except that the total thickness of the fiber assembly was set to 100 mm. Did not.

Comparative Example 5 A sound insulating structure (25) was produced in exactly the same manner as in Example 1 except that the thickness of the high airflow resistance layer of the fiber assembly was 1 mm or less. It could not be compressed and could not be made.

Comparative Example 6 The thickness of the high airflow resistance layer of the fiber assembly was 20 mm, and the air pressure was 0.1 mm.
High airflow resistance layer air flow rate of 600 cc at 01 kg / cm ²
/ Cm ² · min, low airflow resistance layer airflow is 1400cc
A sound-insulating structure (26) was produced in exactly the same manner as in Example 1, except that / cm ² · min was used.

Comparative Example 7 Polyester fiber A having a fiber diameter of 5 μm and a fiber length of about 50 mm
Is 80% by weight, and 20% by weight of a polyester fiber B having a fiber diameter of 14 μm, a fiber length of about 50 mm, and a softening point lower than that of the fiber A by about 90 ° C., except that the weight is 20% by weight. (27), but fiber A
Was too thin to be a nonwoven fabric and could not be produced.

Comparative Example 8 A polyester fiber A having a fiber diameter of 60 μm and a fiber length of about 50 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high ventilation resistance layer at 1500cc / cm ² · mi
n, low airflow resistance layer airflow is 2150 cc / cm ² · mi
Except having set n, the sound insulation structure (28) was produced exactly like Example 1.

Comparative Example 9 A polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 10 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
The sound insulating structure (29) was produced in exactly the same manner as in Example 1 except that it was composed of 20% by weight, but the fiber A was too short to be a nonwoven fabric and could not be produced.

Comparative Example 10 A polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 200 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 50 m.
20% by weight of a polyester fiber B having a softening point lower than that of the fiber A by about 90 ° C. and an air pressure of 0.01 kg / cm
² is 1400 cc / cm ² · m
in, low airflow resistance layer airflow is 2000cc / cm ² · m
A sound insulating structure (30) was produced in exactly the same manner as in Example 1, except that the sample was set to in.

Comparative Example 11 Polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm was 50% by weight, a fiber diameter of 14 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 50% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high airflow resistance layer at 800cc / cm ² · mi
n, low airflow resistance layer airflow is 1500 cc / cm ² · mi
Except having set n, the sound insulation structure (31) was produced exactly like Example 1.

Comparative Example 12 A sound insulating structure (32) was prepared in exactly the same manner as in Example 1 except that 100% by weight of a polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm was used.
No molded body was exhibited and could not be produced.

Comparative Example 13 80% by weight of polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm, and 20% by weight of polyester fiber B having a fiber diameter of 5 μm and a fiber length of about 50 mm and having a softening point lower than that of fiber A by about 90 ° C. The sound insulating structure (33) was produced in exactly the same manner as in Example 1 except that the fiber B
Was too thin to be a nonwoven fabric and could not be produced.

Comparative Example 14 A polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm was 80% by weight, a fiber diameter of 60 μm and a fiber length of about 50 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
Is composed of 20% by weight, and the air pressure is 0.01 kg / cm ²
Resistance of the high airflow resistance layer at 1200cc / cm ² · mi
n, low airflow resistance layer airflow is 2050 cc / cm ² · mi
Except having set it to n, the sound insulation structure (34) was produced exactly like Example 1.

Comparative Example 15 A polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 10 mm.
Polyester fiber B whose softening point is about 90 ° C lower than fiber A
The sound insulating structure (35) was produced in exactly the same manner as in Example 1 except that it was composed of 20% by weight, but the fiber B was too short to be a nonwoven fabric and could not be produced.

Comparative Example 16 Polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm was 80% by weight, a fiber diameter of 14 μm and a fiber length of about 200 m.
20% by weight of a polyester fiber B having a softening point lower than that of the fiber A by about 90 ° C. and an air pressure of 0.01 kg / cm
^The air flow rate of the high airflow resistance layer at 1 is 1300 cc / cm ² · m
in, low airflow resistance layer airflow is 1900 cc / cm ² · m
A sound insulating structure (36) was produced in exactly the same manner as in Example 1, except that the sample was set to in.

Comparative Example 17 80% by weight of a polyester fiber A having a fiber diameter of 25 μm and a fiber length of about 50 mm, a fiber diameter of 14 μm and a fiber length of about 50 mm
Polyester fiber B whose softening point is about 10 ° C lower than fiber A
The sound insulating structure (37) was produced in exactly the same manner as in Example 1 except that it was composed of 20% by weight, but the temperature difference was so small that it could not be made into a nonwoven fabric and could not be produced.

Comparative Example 18 A sound insulating structure (38) was produced in exactly the same manner as in Example 19 except that no heat treatment was performed.

Comparative Example 19 A sound insulating structure (39) was produced in exactly the same manner as in Example 20, except that no embossing treatment was applied.

(Test Example) The following experiments were performed on the sound insulation structures obtained in the above Examples and Comparative Examples.

Test Example (Measurement of Air Flow Rate) Using the samples obtained by the methods of the above Examples and Comparative Examples, JIS L1004, L1018, L1
The air permeability was measured according to the measurement method of the air permeability test specified in No. 096.

Test Examples (Measurement of Sound Insulation Performance) The samples obtained by the methods of the above Examples and Comparative Examples were subjected to sound transmission loss measurement using a reverberation room according to JIS 1416. At this time, the sound insulation level of the mass rule of sound transmission loss (TL) determined by the mass of the entire sound insulation structure for each sample is set to 0 as a reference value.
The difference in sound insulation performance was calculated assuming dB. This difference was averaged in the frequency range of 300 to 500 [Hz] and 500 to 1 k [Hz] and summarized in a graph. Tables 1 and 2 show the test results.

[0096]

[Table 1]

[0097]

[Table 2]

According to the results shown in Tables 1 and 2, the sound transmission loss difference is 300 to 500 [Hz] and 500 to 1 kHz [Hz].
In any of the above frequency ranges, those less than 1 dB were judged to have no effect.

From Table 1, each of the sound insulation structures manufactured in the examples has a sound insulation performance in a low frequency range as compared with the sound insulation level according to the mass rule of sound transmission loss (TL) determined by the mass of the entire sound insulation structure. Was confirmed to improve.

Further, in the comparative example manufactured with the specification out of the claims, as shown in Table 2, a satisfactory value of the sound insulation performance could not be obtained.

[0101]

As described above, the sound insulating structure of the present invention can control the air flow rate by surface treatment, and is lower than the conventional sound insulating structure having a high density layer having no air permeability in its structure. This has the effect of significantly improving the sound insulation performance in the frequency range.

[Brief description of the drawings]

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

[Explanation of symbols]

1 floor panel 2 Sound insulation structure 3 Low density layer 4 High density layer 5 floor carpet

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kyoichi Watanabe Nissan Motor Co., Ltd. (2) Nissan Motor Co., Ltd. (72) Inventor Yoshikazu Nemoto 2 Takaracho 2 In-house (56) References JP-A-7-287581 (JP, A) JP-A-6-247202 (JP, A) JP-A-9-13260 (JP, A) JP-A 8-324320 (JP, A) ) Shokai 56-61000 (JP, U) Shokai 58-168929 (JP, U) Shokai 3-104459 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60N 3/04 B32B 5/06 B32B 5/26 B60R 13/08

Claims (7)

(57) [Claims] 1. A fiber aggregate composed of short fibers mainly composed of polyester, having a fiber diameter of 10 to 40 μm.
m, a fiber having a round cross-section or a modified cross-section fiber (fiber A) having a fiber length of 30 to 100 mm (fiber A) is 70 to 90% by weight, and has a softening point lower than that of the above-mentioned fibers by at least 20 ° C. The fiber (fiber B) having a length of 30 to 100 mm is composed of 10 to 30% by weight, and has an area density of 0.
A fiber aggregate having a thickness of 5 to 3.0 kg / m ² and a thickness of 16 to 60 mm, wherein at least one fiber is aggregated by mechanically and / or thermally treating the surface layer of the fiber aggregate. A high airflow resistance layer, and the difference in airflow between the formed high airflow resistance layer and the other layers is 0.01 kg / air pressure.
sound insulation structure, characterized in that in cm ² is within the range of 400~1400cc / cm ² · min. 2. A high airflow resistance layer having a thickness of 1 to 10 mm is formed from a surface layer by performing a needle punching process on at least one surface of the sound insulation structure to perform airflow control, thereby forming the high airflow resistance layer. When air is allowed to permeate by applying pressure from the vertical direction to the surface where the airflow is transmitted, the difference in air flow between the high airflow resistance layer formed by the needle punching process and the other layers is 400 to 1400 cc at an air pressure of 0.01 kg / cm ² . / Cm ²
The sound insulation structure according to claim 1, wherein the sound insulation structure is within a range of min. 3. A high airflow resistance layer having a thickness of 1 to 10 mm from the surface layer is formed by subjecting at least one surface of the sound insulation structure to heat treatment to control airflow, thereby forming the high airflow resistance layer. in with air permeated under pressure from a direction perpendicular to the plane, 400~1400cc / cm aeration amount difference of the high air flow resistance layer and the other layer formed by heat treatment in air pressure 0.01 kg / cm ² The sound insulation structure according to claim 1, wherein the sound insulation structure is within a range of ² min. 4. A high airflow resistance layer having a thickness of 1 to 10 mm is formed from a surface layer by embossing at least one surface of the sound insulation structure to perform airflow control, thereby forming the high airflow resistance layer. When air is permeated by applying pressure from the direction perpendicular to the surface, the difference in air permeability between the high airflow resistance layer formed by embossing and the other layers is 0.01 kg / air.
^2. The sound insulating structure according to claim 1, wherein the sound insulating structure is in a range of 400 to 1400 cc / cm ² · min in cm ² . 5. When the sound insulation structure is installed on the partition, the high airflow resistance layer in the fiber assembly and the external partition make the sound insulating structure two-dimensional.
Forming a heavy wall sound insulation structure, the ventilation rate of the high ventilation resistance layer,
Thickness and other layer thickness, density, dynamic spring constant,
By manipulating the air flow, the primary resonance frequency can be adjusted to 50-
5. The sound insulation structure according to claim 1, wherein the frequency can be set to an arbitrary frequency of 300 Hz. 6. The double-walled sound-insulating structure, wherein the double-walled structure formed by the sound-insulating structure has a sound transmission level (TL) determined by the mass of the entire structure and a sound insulation level based on the mass rule. In the frequency range of 300 to 1 kHz, the sound insulation structure has a sound transmission loss of 1 to 3 dB on the average frequency.
The sound insulation structure according to claim 5, wherein the sound insulation structure is improved. 7. The sound insulation structure according to claim 6, wherein the sound insulation structure is applied to an automobile floor insulator in a state where a carpet is installed on an upper side of the sound insulation structure, which is located on an interior side of an automobile floor panel. .