JP2956441B2 - Soundproofing material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soundproof material for preventing noise in an engine room of an automobile, for example, from propagating into the room.

[0002]

2. Description of the Related Art As shown in FIG. 12, an automobile 9 is provided with a soundproof material 8 to prevent noise of an engine 92 and the like from propagating into a room 91. Soundproof material 8
Are arranged and fixed on the interior 91 side with respect to a dash panel 95 that separates the engine room 94 and the interior 91. The soundproofing material 8 is placed on the floor of the room 91,
Sometimes used below floor carpets.

[0003] By the way, the conventional soundproof material 8 is, for example, shown in FIG.
As shown in FIG. 3, a skin layer 81, a felt layer 82, a steel plate 8
3 are sequentially laminated asphalt sheets 84 each having a constraining layer. Then, the asphalt sheet 84 side is thermally welded to the dash panel 95. Dash panel 9
The thermal fusion of the asphalt sheet 84 to 5 is performed, for example, in a paint baking furnace in a body painting process. As the skin layer, for example, a vinyl chloride resin sheet is used. As the felt layer 82, anti-hair felt (regenerated cotton, hemp wool) is used.

[0004] The asphalt sheet 84 and the steel plate 83 mainly play a role as a damping material for suppressing the vibration of the dash panel 95 from propagating to the indoor side. On the other hand, the felt layer 82 and the skin layer 81 mainly serve as a sound insulating material for absorbing and blocking noise passing through the dash panel 95. The soundproofing material has a greater soundproofing effect as the overall weight and thickness are larger.

[0005]

However, the above conventional soundproofing materials have the following problems. That is, in recent years, in automobiles, there has been an increasing demand for weight reduction as a measure for improving fuel efficiency. Therefore, only for the purpose of soundproofing,
It is not permissible to increase the amount of soundproofing material.

[0006] In the above conventional sound insulation 8 is, as damping material that can particularly reduce the vibration in the following low-frequency domain frequency 500H _Z (Hz), asphalt sheet 84 and steel sheet 83 is used. Further, the felt layer 82 and the skin layer 81 are used to block noise in the middle and high frequency regions.

The dash panel 95 is exposed to a high temperature of 50 to 60 ° C. by the heat of the engine 92. Therefore, as described above, as the damping material, the asphalt sheet 84 and the steel plate 83 having high damping performance on the high temperature side are used. As a result, a heavy material must be used as the soundproofing material 8, which is against the weight reduction of automobiles. Also,
The above-mentioned conventional soundproofing material requires a heating step for heat-sealing the asphalt sheet 84 to the dash panel 95, and also requires a means for holding the soundproofing material at the time of heat-sealing. Mounting operation is complicated.

Also, since the asphalt sheet 84 is heat-sealed to the dash panel, it is difficult to recycle (reuse) the soundproofing material. In addition, asphalt sheet 8
No. 4 is heavy and sticky at high temperatures in summer or in a storage place in a factory. for that reason,
Until the soundproofing material 8 is attached to the dash panel 95,
It is necessary to consider the storage location and storage temperature of the soundproofing material.
As described above, the soundproofing material using the asphalt sheet 84 has many problems in its weight, storability, and handleability. The present invention has been made in view of the above-mentioned conventional problems, and is intended to provide a lightweight, excellent soundproofing effect and recyclable soundproofing material.

[0009]

According to the present invention, a skin layer and a spring constant of 0.1 are provided.
A first felt layer having a low elasticity of 0.5 to 0.5 × 10 ⁶ N / m, an intermediate sheet layer, and a spring constant of 2 to 10 × 10 ⁶ N / m.
And a second felt layer having high elasticity are sequentially laminated.

The most remarkable point in the present invention is that the skin layer, the first felt layer, the intermediate sheet layer, and the second felt layer are sequentially laminated, and the first felt layer and the second felt layer are formed as described above. It has a specific spring constant. As the skin layer, a sheet of polyvinyl chloride or the like is used. Moreover, it is preferable that the thickness is 1-3 mm. If it is less than 1 mm, the sound insulation may be reduced. On the other hand, if it exceeds 3 mm, the sound insulation may be improved but the weight of the soundproofing material may increase.

Next, the first felt layer has a spring constant of 0.0
A low-elastic felt layer of 5 to 0.5 × 10 ⁶ N / m is used. If it is less than 0.05 × 10 ⁶ N / m, there is a problem that the sound insulation is reduced. On the other hand, if it exceeds 0.5 × 10 ⁶ N / m, there is a problem that the vibration damping is reduced. As the first felt layer, there is a felt made of polypropylene having a bulk density of 10 to 40 kg / m ³ . If the bulk density is less than 10 kg / m ³ , the sound insulation is not sufficient. On the other hand, if it exceeds 40 kg / m ³ , there is a problem that the vibration damping property is reduced.

The thickness of the first felt layer is 5 to 20 m.
m is preferable. If it is less than 5 mm, the sound insulation is low. On the other hand, if it exceeds 20 mm, the corresponding improvement in sound insulation is small, and the thickness of the sound insulating material becomes too large. The above-mentioned spring constant and the thickness of the first felt layer are related to each other. For example, when the thickness is 5 mm, the spring constant of the first felt layer is 0.5 × 10 ⁶ N / m, and when the thickness is 20 mm, It is preferable that the spring constant be 0.05 × 10 ⁶ N / m. Therefore, the first felt layer has a thickness of 5 to 20 mm.
In the range of 0.5 to 0.05 × 10 ⁶ N
/ M is preferably selected.

Next, the intermediate sheet layer is located between the first felt layer and the second felt layer, and has a function of attenuating vibrations propagated from the second felt layer.
As the intermediate sheet layer, a sheet of polyvinyl chloride, polypropylene, polyurethane, asphalt, or the like is used. The thickness is preferably set to 1 to 3 mm. 1
If it is less than 3 mm, the sound insulation is low, while if it exceeds 3 mm, the attenuation effect corresponding thereto is small, and the weight of the soundproofing material increases.

The intermediate sheet layer has a porosity of 0.5-1.
It is preferred to have 0% vents. Here, the porosity refers to the total area (%) of the ventilation holes with respect to the area of one surface of the intermediate sheet layer. It is preferable that the diameter of the ventilation hole is 1 to 10 mm.

Thus, when the second felt layer vibrates, air in the second felt layer is discharged to the first felt layer, and air is sucked into the second felt layer from the first felt layer. And the vibration damping effect of the second felt layer is improved. If the hole diameter is less than 1 mm, the effect of air permeability is small, while if it exceeds 10 mm, the vibration damping effect of the intermediate sheet layer may be reduced.

Next, the second felt layer has a spring constant of 2 to 2.
10 × 10 ⁶ N / m, higher elasticity than the first felt layer. If it is less than 2 × 10 ⁶ N / m, the vibration damping effect is low.
On the other hand, if it exceeds 10 × 10 ⁶ N / m, there is a problem that the vibration damping effect at 100 Hz or less decreases and the weight of the felt increases. The thickness of the second felt layer is 1
It is preferable to set it to 0 to 25 mm. If it is less than 10 mm, the vibration damping effect is low, and if it exceeds 25 mm, the effect of improving the vibration damping effect is small.

The above-mentioned spring constant and the thickness of the second felt layer are related to each other. For example, when the thickness is 10 mm, the spring constant of the second felt layer is 10 × 10 ⁶ N /
m, on the other hand, when the thickness is 25 mm, the spring constant of the second felt layer is preferably 2 × 10 ⁶ N / m. Therefore, the second felt layer preferably has a spring constant of 10 to 2 × 10 ⁶ N / m in a thickness range of 10 to 25 mm. In addition, as a material of the second felt layer,
Use felt such as recycled cotton.

Preferably, the second felt layer is lightly bonded to the intermediate sheet layer. As a result, the second felt layer, which is too flexible and difficult to handle, is reinforced by the intermediate sheet layer, and the work of attaching the soundproofing material to the dash panel of the vehicle becomes easy. This is the same in the relationship between the first felt layer and the skin layer.

Since the soundproofing material of the present invention is composed of the four layers described above, the soundproofing material must be mounted on a mating material such as a dash panel before it is mounted.
They can also be laminated in layers and lightly bonded together. Further, this laminate can be formed along the three-dimensional shape of the mating material. Contrary to the above, it is also possible to stack the layers one by one when attaching them to the mating member and fix them with a stapler or the like. The soundproofing material of the present invention
In addition to soundproofing materials for automobiles such as dash panels and floors of automobiles, it is also effective as a soundproofing material for factories, buildings, music rooms, houses and the like.

[0020]

[Operation and Effect] The soundproofing material of the present invention has the above-mentioned structure, and thus exhibits excellent sound insulating properties. The reason is considered as follows. That is, the second felt layer side is arranged on the noise source side. Therefore, the noise first enters the highly elastic second felt layer, where the vibration is attenuated first, and further the vibration is attenuated in the intermediate sheet layer. The noise that has entered the low-elastic first felt layer from the intermediate sheet layer is absorbed here, and is also absorbed in the skin layer. And, by these synergistic effects, an excellent soundproofing effect is exhibited.

The above points will be described below by taking as an example a case where the soundproofing material of the present invention is mounted on a dash panel of an automobile (see FIG. 2). That is, noise intrusion into the cabin of an automobile is due to the fact that the vibration of the engine propagates through the engine mount and the vibration generated by the fine irregularities on the road surface propagates through the tire and suspension system. The soundproofing material of the present invention aims at a vibration damping effect of reducing the propagation of vibration transmitted from, for example, a dash panel to the skin layer of the soundproofing material.

The vibration characteristics of the dash panel are caused by the fact that the vibration transmitted from the engine mount or the like is not transmitted as it is, but the dash panel resonates in accordance with the frequency of the transmitted vibration, and the vibration is attenuated at a certain frequency. , On the contrary, it becomes larger (for example, FIG. 3
reference). In the conventional soundproof materials, it was suppress the vibration of the dash panel using the vibration damping materials made of asphalt sheets and steel plates. However, in the present invention, the vibration damping effect of the four layers is exerted, and both have different sound insulation functions.

Further, in the present invention, unlike the conventional soundproofing material, no steel plate is used as a vibration damping material. Therefore, the soundproofing material of the present invention is about 30 times less than the conventional soundproofing material.
% Weight, and a great reduction in weight can be achieved.

Further, the soundproofing material of the present invention does not use an asphalt sheet that is heat-sealed to the dash panel or the like, unlike the conventional soundproofing material. Therefore, the soundproofing material can be reused and the recyclability is good. Furthermore, compared with the case of using asphalt sheet, storage, handling,
Also excellent in lightness. Therefore, according to the present invention,
It is possible to provide a soundproof material that is lightweight, has excellent soundproofing effects, and has excellent recyclability.

[0025]

【Example】

Embodiment 1 A soundproofing material according to an embodiment of the present invention will be described with reference to FIGS. The soundproofing material 10 of the present example is composed of the skin layer 1 and the first elastic material having a low elasticity of 0.05 to 0.5 × 10 ⁶ N / m.
Felt layer 2, intermediate sheet layer 3, spring constant 2 to 10
The second felt layer 4 having a high elasticity of 10 ⁶ N / m is sequentially laminated. In this example, a sheet of a hard recycled vinyl chloride resin having a thickness of 2 mm was used as the skin layer 1. As the first felt layer 2, a felt made of polypropylene was used. It has a bulk density of 15 kg / m
³ , and the thickness was 10 mm.

As the intermediate sheet layer 3, a sheet of the same hard recycled vinyl chloride resin as the skin layer 1 was used. This has a large number of ventilation holes 31 having a thickness of 2 mm and a diameter of 5 mm. The air holes 31 have an opening ratio of 8% with respect to one surface area of the intermediate sheet layer. Recycled cotton felt is used as the second felt layer 4 and its thickness is 15 mm.
The bulk density was 96 kg / m ³ .

As shown in FIG. 2, the soundproofing material 10 constructed as described above was fixed to the dash panel 95 of the vehicle with the clip with the second felt layer 4 of the soundproofing material facing the dash panel 95. Then, when the engine of the automobile was operated and the sound insulation was measured, the sound insulation effect was substantially equal to or higher than that of the sound insulation material shown in the conventional example.

Further, since the soundproofing material of this embodiment does not use a steel plate as a vibration damping material as in the above-described conventional example, it is possible to significantly reduce the weight, and its weight is about 30% of the conventional product. Was. Further, the soundproofing material of the present embodiment does not use an asphalt sheet to be heat-sealed as in the above-mentioned conventional product, and therefore is excellent in recyclability, storage property and handling property.

Example 2 Various soundproofing materials (samples Nos. 1 to 8) according to the present invention and soundproofing materials (samples C1 and C2) as comparative examples were produced, and the soundproofing effects of these on various frequencies were measured. The conditions of each soundproofing material are shown in Table 1, and the measurement results are shown in FIGS. Regarding the soundproofing material of the present invention, in addition to the conditions shown in Table 1,
The materials and the like for each layer were the same as those shown in Example 1. Also,
The table shows the total thickness of the soundproofing material (mm) and the soundproofing material 1 m
The weight per ² (kg / m ² ) was shown.

Comparative Example C1 is a soundproofing material shown in the above-mentioned conventional example, which comprises a skin layer, a recycled cotton felt layer, a steel sheet and an asphalt sheet (FIG. 13). The skin layer is the same material as the skin layer of Example 1, and the recycled cotton felt layer is the same material as the second felt layer of Example 1 and has a thickness of 20 mm and a bulk density of 9
It was 6 kg / m ³ . The steel plate is 0.8mm thick.
Asphalt sheet is 3mm thick, specific gravity 1000kg /
m ³ .

Further, Comparative Example C2 has a three-layer structure without using an intermediate sheet layer. The skin layer is made of the same material as in Example 1, and the first felt layer has a thickness of 12 mm and a bulk density of 30.
kg / m ³ of PET (polyethylene terephthalate) felt, also one using thickness 10 mm, regeneration cotton felt having a bulk density of 96 kg / m ³ as the second felt layer. Sample 8 of the present invention uses an intermediate sheet layer having no air holes.

Next, in measuring the above soundproofing effect,
Place the sample on a steel plate fixed to a fixed frame,
The vibration plate was vibrated. Then, the vibration level of the upper surface of the skin layer of the vibration plate and the soundproofing material was measured, and the vibration level (X) was calculated by the following equation. Vibration level (X) = log
(Vibration level X ₁ in skin layer) −log (Vibration level X _{0 of} steel plate)

In FIGS. 3 to 11 showing the above measurement results, the frequency (H _Z ) at the time of vibration is plotted on the horizontal axis, and the vibration level (X) dB is plotted on the vertical axis. In the figure, when the vibration level (X) is 0 (zero), the soundproof effect is zero,-(minus) indicates that there is a soundproof effect, and + (plus) indicates the reverse.

Next, the soundproofing effect of each sample will be described with reference to FIGS. First, FIG. 3 shows Sample 1 of the present invention and Comparative Examples C1 and C2. As can be seen from the figure, these three samples have a frequency of 100H.
Below _Z , the vibration level (X) is the same, but above that, Sample 1 of the present invention shows an excellent soundproofing effect. Next, FIGS. 4A and 4B both show a product of the present invention, in which the intermediate sheet layer has a vent hole (Sample 1) and does not have a vent hole (Sample 8). From the figure, it can be seen that the soundproofing effect is slightly larger with the vent hole.

FIGS. 5 to 11 show measured values of the samples 1 to 7, respectively. In each figure, main peak values in each resonance region are also shown. First, as shown in FIGS. 5 to 11, Samples 1 to 7 were all Comparative Examples C1 and C2.
It can be seen that a superior soundproofing effect is exhibited as compared to (FIG. 3). Also, comparing FIGS. 5, 6, 7 and 8 (samples 1, 2, 3 and 4), they show the first felt layer and the second felt layer.
The felt layers are the same, and the thickness of the skin layer and the thickness of the intermediate sheet layer are different.

[0036] Then, these are the following first resonance peak frequency 100H _Z, without deteriorating the secondary resonance or less, it can be varied between 12.24 to 8.66. That is, these indicate that the vibration level (X) can be controlled to the above value by changing each of the layers as described above.

Next, comparing FIGS. 5, 9 and 11 (samples 1, 5 and 6), they show the skin layer, the first felt layer,
The thickness of the second felt layer is the same, and the intermediate sheet layer has a different hole opening ratio. These figures, by changing the opening ratio, it can be seen that it is possible to change the resonance of the following frequency 100H _Z. FIG.
(Sample 7) indicates that the primary resonant less frequency 100H _Z, can be largely lowered until quite 6.62DB.

As is known from FIGS. 2 to 11, by changing the thickness of the skin layer, the thickness of the intermediate sheet layer and the porosity, it is possible to obtain a soundproofing material having various soundproofing effects in a wide frequency range. You can see that.

[0039]

[Table 1]

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a soundproofing material according to a first embodiment.

FIG. 2 is a cross-sectional view showing a mounted state of the soundproofing material in the first embodiment.

FIG. 3 is a graph showing the relationship between Sample 1 and Comparative Examples 1 and 2 in Example 2;
FIG. 4 is a diagram illustrating a relationship between a vibration level (X) and a frequency.

FIG. 4 is a diagram showing a relationship between frequency and vibration level (X) of samples 1 and 8 in Example 2.

FIG. 5 is a diagram showing the relationship between the vibration level (X) and the frequency of the sample 1 in the second embodiment.

FIG. 6 is a diagram showing the relationship between the vibration level (X) and the frequency of the sample 2 in the second embodiment.

FIG. 7 is a diagram showing the relationship between the vibration level (X) and the frequency of the sample 3 in the second embodiment.

FIG. 8 is a diagram showing the relationship between the vibration level (X) and the frequency of the sample 4 in the second embodiment.

FIG. 9 is a diagram showing the relationship between the vibration level (X) and the frequency of the sample 5 in the second embodiment.

FIG. 10 is a diagram showing the relationship between the vibration level (X) and the frequency of the sample 6 in the second embodiment.

FIG. 11 is a diagram showing a relationship between a frequency and a vibration level (X) of the sample 7 in the second embodiment.

FIG. 12 is an explanatory view of an arrangement of a soundproof material for an automobile in a conventional example.

FIG. 13 is a cross-sectional view of a soundproofing material in a conventional example.

[Explanation of symbols]

 1. . . 9. epidermal layer, . . 1. soundproofing material, . . 2. first felt layer; . . 30. intermediate sheet layer; . . Vents, 4. . . Second felt layer, 95. . . Dash panel,

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-328605 (JP, A) JP-A-6-259080 (JP, A) JP-A-2-220883 (JP, A) 168145 (JP, U) Shokai Sho 62-139756 (JP, U) Shokai Hei 5-66697 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B32B 1/00-35 / 00 B60R 13/08 G10K 11/16

Claims (3)

(57) [Claims] 1. A skin layer having a spring constant of 0.05 to 0.5 ×
A first felt layer having low elasticity of 10 ⁶ N / m, an intermediate sheet layer, and a second elastic layer having high elasticity of 2 to 10 × 10 ⁶ N / m;
A soundproofing material characterized by being sequentially laminated with a felt layer. 2. The intermediate sheet layer according to claim 1, wherein the intermediate sheet layer has ventilation holes, and the total opening ratio of the ventilation holes is 0.5 to 10%.
A soundproofing material characterized by being: ^3. The soundproofing material according to claim 1, wherein the first felt layer is a polypropylene felt having a bulk density of 10 to 40 kg / m ³ .