JPH10254453A - Sound insulating member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make sound insulating effect excellent easily applicable to a narrow and small space by covering at least the outer surface of a sound absorption layer composed of a porous member with a film layer whose air permeable amount is smaller than a specified value/sec. based on a specified pressure difference and providing a sound absorbing layer on the side face. SOLUTION: At least the outer surface 11 of a sound absorbing layer 1 composed of a porous part is covered with a film layer 2 whose air permeable amount is smaller than 0.01cc/cm<2> /sec. based on the pressure difference of 2.039×1/10<4> mmH2 O and the side face 12 of the sound absorbing layer 1 is a sound insulating material 4 having a sound absorbing layer. The sound absorbing layer 1 is a main body for exhibiting a sound insulating effect, absorbs acoustic energy as vibration energy, etc., and is formed with a proper porous member for exhibiting the sound insulating effect. By this constitution, the leakage of sound incapable of sound incapable of being absorbed by the sound absorbing layer 1 to the outside in prevented since it is reflected by the film layer 2, thus, the excellent sound shielding effect is attained and it is easily mounted even in a narrow and small space, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound-insulating material having an excellent sound-insulating effect, which is suitable as a device-mountable type such as a device mounted between a hard disk drive main body and a substrate.

[0002]

2. Description of the Related Art In a hard disk drive of a personal computer or the like, a motor noise at the time of driving or a wind noise of a disk is generated, which causes noise to an operator or a neighbor of the apparatus. It is arranged to reduce the generated sound.

Conventionally, foams made of polyurethane foam or the like have been known as the above-mentioned soundproofing material, but there has been a problem that the sound leakage is large and the sound insulating effect is poor. For this reason, composite structures such as those obtained by covering the outer surface of a foam with a film and those obtained by laminating a melt-blown layer of a resin or the like on a film have been proposed (JP-A-56-157347).
JP, JP-A-4-345834, JP-A-7-2
No. 61768).

[0004] However, even in the case of a conventional structure-type soundproofing material such as one covered with a film, there is a problem that the soundproofing effect is insufficient and satisfactory noise and soundproofing cannot be achieved.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to develop a sound insulating material which can be easily applied to a small space or the like and has an excellent sound insulating effect.

[0006]

According to the present invention, at least the outer surface of a sound absorbing layer made of a porous member is formed at 2.039 × 1/10 ⁴ mmH _2.
Those aeration amount based on the air pressure difference of O is then coated with the following film layer 0.01 cc / cm ² / sec, and also on the side surface of the backing layer to provide a soundproofing material which is characterized by having a sound insulation layer It is.

[0007]

According to the soundproofing material of the present invention, sound that cannot be completely absorbed by the sound absorbing layer is reflected by the substantially air-impermeable film layer to prevent or prevent leakage to the outside. An excellent sound insulation effect is exhibited, and advanced noise prevention can be achieved. Further, since the soundproofing material is excellent in flexibility, the soundproofing material can be easily installed even in a small space or the like, and it is possible to suppress an increase in the size of the entire device due to an increase in the thickness of the soundproofing material.

In the above, the air permeability of the film layer is 2.
0.01 based on the pressure difference of 039 × 1/10 ⁴ mmH ₂ O
The limitation of less than cc / cm ² / sec indicates a critical effect difference between sound transmission and reflection shielding, and the air flow rate is not more than 0.1 cc / cm ² / sec.
If it exceeds 01 cc / cm ² / sec, sound transmission is so large that a satisfactory soundproofing effect cannot be exhibited.

In the present invention, when the entire surface of the sound absorbing layer is covered with the film layer, it is feared that sound does not enter the sound insulating layer due to the above-mentioned reflection effect and the sound insulating effect is not exhibited. The film layer on the side (inner surface side) is in close contact with the noise source, and its existence can be neglected according to the mass rule, and the film layer vibrates integrally with the noise source.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The soundproofing material of the present invention has a structure in which at least the outer surface of a sound absorbing layer made of a porous member is 2.039 × 1/1.
0 ⁴ mmH ₂ aeration amount based on the air pressure difference of O is 0.01 cc / cm ²
Per second or less, and also has a sound insulation layer on the side surface of the sound absorption layer. Examples are shown in Figs.
As shown in FIG. 1 is a sound absorbing layer, 11 is its outer surface, 12
Is a side surface, 13 and 14 are end portions, 2 and 21 are film layers, and 3 is a spacer.

The sound-absorbing layer is a main component of the sound-absorbing effect, and is formed of an appropriate porous member that absorbs sound energy as vibration energy or the like and converts it into heat energy or the like to exhibit the sound-absorbing effect. Therefore, there is no particular limitation on the porous member, and any of the known sound insulating materials can be used.
When applied to a narrow space or the like, a material having excellent compressibility is preferable.

In general, for example, a fiber aggregate obtained by assembling suitable natural or synthetic organic or inorganic fibers into a nonwoven fabric or the like,
Alternatively, a foam or the like is used. As for the foam, for example, urethane foam, olefin foam such as polyethylene or polypropylene, acrylic foam, vinyl chloride foam, ethylene / propylene foam, S
An appropriate material such as a BR foam, an NR foam, an NBR foam, or a blend foam thereof may be used. The foam preferably has an open-cell structure from the viewpoint of the soundproofing effect and the like. Further, the sound absorbing layer may be formed as a laminate or a mixed layer of two or more kinds of porous members.

The form of the sound absorbing layer can be appropriately determined according to the purpose of use, such as the application location of the sound insulating material, as shown in the above-mentioned example, and the thickness thereof is also arbitrary. Generally, the thickness is 100 mm or less, based on the apparent thickness, particularly 1 to 70 mm, particularly 3 to 40 mm. The sound absorbing layer does not need to have a uniform thickness as in the illustrated example, and may have a partially different thickness.

The sound-absorbing layer having a partially different wall thickness is formed by filling a chip made by, for example, crushing a porous member into flakes into a predetermined mold by applying an adhesive to the surface thereof. It can be formed efficiently by a compression molding method or the like.

The soundproofing material of the present invention comprises a sound absorbing layer having at least an outer surface covered with a film layer and a sound insulating layer provided on the side of the sound absorbing layer.
The air flow rate based on the pressure difference of 10 ⁴ mmH ₂ O is 0.01 cc /
It was formed with a material of cm ² / sec or less.

The film layer may be formed of an appropriate material that satisfies the above-mentioned air flow rate. In general, films made of various plastics are used. In particular, a material having the above-described airflow characteristics with a film thickness as small as possible, particularly 500 μm or less, and more preferably 200 μm or less is preferable.

The film layer is disposed at least on the outer surface of the sound absorbing layer, that is, on the surface of the sound absorbing layer opposite to the noise source side.
Therefore, the film layer may be arranged on the side surface 12 in addition to the outer surface 11 of the sound absorbing layer 1 as illustrated in FIG.
As illustrated in FIG. 2, the sound absorbing layer 1 may be disposed so as to surround the entire surface, that is, the entire sound absorbing layer. When a film layer is provided on the side surface of the sound absorbing layer, the film layer forms a sound insulating layer on the side surface of the sound absorbing layer. The film layer is bonded and integrated with the sound absorbing layer as needed, and an appropriate method such as an adhesive or heat fusion can be applied as needed at the time of the integration.

In the above, the film layer has 2.039
The air flow rate based on the pressure difference of × 1/10 ⁴ mmH ₂ O is 0.01
A film in which ventilation holes are formed in a continuous film film of cc / cm ² / sec or less can also be used. The film layer in which the air holes are formed functions as an air vent at the time of compressing the sound insulating material, and can be preferably used when the entire sound absorbing layer 1 is surrounded by the film layer 21 as illustrated in FIG.

Therefore, the air holes in the film layer need only be formed so that air can be released when the soundproofing material is compressed. From the viewpoint of the sound leakage preventing effect of the film layer, the form in which the ventilation holes are arranged at the corners on the noise source side of the sound absorbing layer is preferable.

The sound insulating layer on the side of the sound absorbing layer, together with the above-mentioned film layer, if necessary, is in a state where the end of the sound absorbing layer is more airtight than the central part when the sound insulating material is attached as illustrated in FIGS. Can be formed. By the way, in the example shown in FIG. 3, the end portion 13 of the sound absorbing layer 1 is formed thicker than the central portion, and when the soundproofing material 4 is mounted at a predetermined position, the end portion is compressed more than the central portion. This is to form a highly airtight state.

FIG. 4 shows an example in which a spacer 3 is disposed at an end of the sound absorbing layer 1 and the thickness of the spacer is increased.
When the soundproofing material 4 is mounted at a predetermined location, its end is compressed more than its central portion to form a highly airtight state. The spacer is fixed to the sound absorbing layer via an adhesive. On the other hand, in the example illustrated in FIG. 5, the end portion 14 of the sound absorbing layer 1 is impregnated and filled with an airtight agent to form a highly airtight state.

In the above, the spacer and the airtight agent can be formed of an appropriate material such as rubber or plastic. In the case of the airtight agent filling method, it is necessary to make it compressible by an appropriate method such as a method of filling a space having a slight gap or a method of filling a stretchable airtight agent. It is more preferable than such points.

The sound insulation layer disposed on the side surface of the sound absorption layer has a thickness of 2.039 × 1/1 based on the mounting state in terms of the soundproof effect and the like.
0 ⁴ mmH ₂ aeration amount based on the air pressure difference of O is 0.05 cc / cm ²
/ Sec or less, especially 0.02 cc / cm ² / sec or less, especially 0.0
It is preferably at most 1 cc / cm ² / sec.

The soundproofing material of the present invention is formed in a predetermined form in advance and interposed between various members such as between the main body 5 of the hard disk drive and the substrate 6 as shown in FIG. It can be used for various soundproofing treatments according to the related art, for example, by attaching a tape-shaped or sheet-shaped material by an appropriate method such as a winding method or a sticking method.

[0025]

【Example】

Example 1 A sound absorbing sheet made of an ether urethane foam having a foaming ratio of about 30 and an apparent thickness of about 5 mm, which is commercially available as a sound absorbing material for a hard disk, and having a thickness of 100 μm, A polyethylene film having an air permeability of less than the measurement limit based on a pressure difference of 0.039 × 1/10 ⁴ mmH ₂ O was bonded via a vinyl acetate adhesive to obtain a soundproofing material.

Example 2 As a polyethylene film having a thickness of 100 μm,
Example 1 except that the air flow rate based on the pressure difference of 039 × 1 × 10 ⁴ mmH ₂ O was 0.01 cc / cm ² / sec.
A soundproofing material was obtained according to.

Example 3 A soundproofing material was obtained in the same manner as in Example 1, except that the entire sound absorbing sheet was wrapped with a polyethylene film.

Comparative Example 1 A sound absorbing sheet was used as a soundproofing material without attaching a polyethylene film.

Comparative Example 2 A polyethylene film having a thickness of 100 μm was used.
Example 1 except that the air flow rate based on the pressure difference of 039 × 1/10 ⁴ mmH ₂ O was 0.02 cc / cm ² / sec.
A soundproofing material was obtained according to.

Evaluation Test As shown in FIG. 8, the soundproofing materials obtained in Examples and Comparative Examples were installed between the main body of a hard disk drive and a substrate, and the soundproofing material 82 was placed on a table 81 provided in an acoustic-free room. The microphone 83 was disposed at a position 300 mm (d) above the device 82 and sound was measured via an analyzer 85. In the case of a soundproofing material having a film layer on one side, the side without the film layer was arranged as the device side.

The results are shown in the following table. In addition, the sound level when there is no soundproofing material is shown as a blank.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a sectional view of another embodiment.

FIG. 3 is a sectional view of still another embodiment.

FIG. 4 is a sectional view of still another embodiment.

FIG. 5 is a sectional view of still another embodiment.

FIG. 6 is a sectional view of still another embodiment.

FIG. 7 is a sectional view of an application example.

FIG. 8 is an explanatory diagram of a sound measurement test.

[Explanation of symbols]

 4: soundproofing material 1: sound absorbing layer 11: outer surface 12: side surface 13, 14: edge 2, 21: film layer 3: spacer

Continuation of front page (72) Inventor Yasunori Sugihara 1-2-1 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation

Claims (6)

[Claims] At least the outer surface of the sound absorbing layer made of a porous member is a film layer having a ventilation rate of 0.01 cc / cm ² / sec or less based on a pressure difference of 2.039 × 1 × 10 ⁴ mmH ₂ O. A soundproofing material which is covered and has a sound insulation layer also on the side surface of the sound absorption layer. 2. The soundproofing material according to claim 1, wherein the soundproofing layer has a film layer as a sound insulating layer on the entire surface of the sound absorbing layer or on a side surface of the sound absorbing layer. 3. The soundproofing material according to claim 1, wherein the soundproofing layer on the side surface of the sound absorbing layer forms a more airtight state at the end of the sound absorbing layer than at the center when the soundproofing material is mounted. 4. The soundproofing material according to claim 3, wherein the high airtight state is due to compression of the end of the sound absorbing layer or filling of the end of the sound absorbing layer with an airtight agent. 5. The soundproofing material according to claim 1, wherein the porous member forming the sound absorbing layer is made of a foam or a fiber aggregate. 6. The continuous membrane film according to claim 1, wherein the film layer has a ventilation rate of 0.01 cc / cm ² / sec or less based on a pressure difference of 2.039 × 1 × 10 ⁴ mmH ₂ O. A soundproofing material formed of