JP2000062067A - Vibration reducing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop a vibration reducing material, which is excellent in a vibration reducing power, exhibits high grade acoustic insulation, vibration insulation or the like, can easily be applied to a narrow space or the like and can be used for various purposes such as an acoustic insulating material, a vibration insulating material or the like. SOLUTION: This vibration reducing material 2 has a film layer 22 on one side or both sides of a porous member 21, the absolute value of a characteristic impedance of which is 800 kg/m2.S or more in a frequency range of 1.0-3.0 kHz. As a result, the porous member displays an excellent reducing power to the vibration such as the noise or the like incident thereover and the film layer displays excellent noise-insulating effects or the like so as to show excellent muffling effects, vibration-proofing effects, resulting in allowing to realize high grade prevention of noise, vibration or the like. As a result, a favorably manageable vibration reducing material used for various objects such as an acoustic insulating material, a sound absorbing material, a noise insulating material, a vibration insulating material, a vibration proofing material or their composite functional material or the like is obtained. In addition, a whole device can be prevented from becoming a large scaled one due to the thicker wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration reducing material which is excellent in vibration reducing ability and is suitable as a soundproof material or a vibration damping material in a driver of an information recording electronic device.

[0002]

2. Description of the Related Art Vibration-reducing materials exhibiting sound-proofing and vibration-proofing by absorbing and reflecting vibrations are, for example, sound-proofing materials, sound-absorbing materials, sound-insulating materials, vibration-damping materials, vibration-proofing materials, and composites thereof. It is used as a functional material for various purposes. By the way, HDD (hard disk drive) in personal computers, etc.
And DVDD (Digital Video Disc Drive), CD
In the D (Compact Disc Drive), the noise of the motor and the wind noise of the disc are generated when driving, and it becomes noise to the operator and the neighbors of the device. Therefore, the vibration reducing material is placed between the drive body and the board as a soundproof material. Therefore, the generated sound is reduced.

Conventionally, a foam made of polyurethane foam or the like has been known as the vibration reducing material. However, when it is used as a soundproof material, there is a problem that the sound leakage is large and the soundproofing effect is poor. . Therefore, those with a limited static spring constant of the foam, those with a fine uneven polymer film attached to the inner wall surface of the foam, those with the outer surface of the foam covered with a film, melt-blown layer of resin or the like on the film. Laminates and the like have been proposed (JP-A-56-15).
7347, JP-A-59-102294, JP-A-4-40381, JP-A-4-345834, JP-A-7-261768).

However, any of the conventional vibration reducing materials has a poor ability to reduce vibration, and when it is used as a soundproof material, for example, it cannot achieve satisfactory noise prevention because of insufficient sound deadening effect due to soundproofing, etc. There is a problem in that the manufacturing process is complicated and the manufacturing efficiency is poor in the case of an uneven polymer film attachment or the like.

[0005]

The present invention has an excellent function of reducing vibration, exhibits a high degree of soundproofing and vibration-proofing, can be easily applied to a narrow space, and is excellent in manufacturing efficiency. The problem is to develop a vibration reducing material that can be used for various purposes such as materials.

[0006]

According to the present invention, the absolute value of the characteristic impedance is 8 in the frequency range of 1.0 to 3.0 kHz.
A vibration reducing material having a film layer on one side or both sides of a porous member of 00 kg / m ² · S or more.

[0007]

EFFECTS OF THE INVENTION According to the vibration reducing material of the present invention, the porous member exhibiting the above-mentioned impedance characteristic exhibits an excellent reducing ability against vibration such as sound incident on the porous member, and the film layer has an excellent sound insulation effect. Exhibits vibration propagation prevention effect. Therefore, it is possible to achieve a high level of noise prevention and vibration prevention by exhibiting excellent sound deadening effect and anti-vibration effect.For example, a soundproof material, a sound absorbing material, a sound insulating material, a vibration damping material, a vibration damping material, or a composite function material A vibration reducing material that can be used for various purposes can be obtained. Further, the porous member and the film layer are excellent in manufacturing efficiency, the handleability is improved by the reinforcing effect of the film layer, the excellent mounting workability is exhibited, and variations in performance such as soundproofing and vibration damping can be suppressed. Further, by using the compressible porous member, it is possible to easily mount the device in a narrow space or the like, and it is possible to suppress the increase in size of the entire device due to the thickening of the vibration reducing material.

In the above, the damping constant is α and the frequency is f
When the expression: α ≧ 0.01 fneper / m is satisfied, the effects of noise reduction and vibration isolation are dramatically improved, and more advanced noise prevention and vibration prevention can be achieved. Further, when a porous member having a repulsive stress of 10 to 200 gf / cm ² at 50% compression is used, it is possible to easily mount it in a narrow space or the like while preventing deformation of adjacent members, and also easy to manufacture. Is.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The vibration reducing material according to the present invention is 1.0
In the frequency region of up to 3.0 kHz, a porous member having an absolute value of characteristic impedance of 800 kg / m ² · S or more has a film layer on one side or both sides. An example thereof is shown in FIG. 2 is a vibration reducing material, 21 is a porous member, and 22 is a film layer. Note that FIG. 1 shows an example in which the vibration reducing material 2 is applied between the HDD body 1 and the substrate 3.

Any porous member may be used as long as it has the above-mentioned characteristics. Particularly, from the viewpoints of sound deadening and vibration damping effects, the absolute value is 1000 kg / m ² · S or more, especially 1200 kg / m ²・ S
Above all, a porous member of 2000 to 13000 kg / m ² · S is particularly preferable. Therefore, as the porous member, for example, a fiber assembly formed by assembling appropriate fibers of natural or synthetic organic or inorganic into a non-woven fabric, or an olefin-based or urethane-based fiber,
Acrylic, vinyl chloride, SBR, NR, NBR
Appropriate materials such as foams of the system and their blends can be used. The vibration reducing material may be formed as a laminated body or a mixed layer of two or more kinds of porous members. It is preferable that 30% or more of the cells of the foam have an open-cell structure in terms of soundproofing, vibrationproofing, and deformation prevention.

The porous member which can be preferably used in view of the above-mentioned conditions is a cyclic or non-conjugated double bond such as ethylene, propylene and butene-1, an α-olefin, and dicyclopentadiene and ethylidene norbornene. Copolymers containing a cyclic polyene as a component, in particular ethylene 45 to 70 mol%, α-olefin 5 to 20 mol%,
Polyene of 50 to 10 mol%, especially Mooney viscosity M
EP with L _{1 + 2} (100 ° C) of 30 to 110
It is a DM foam.

Further, the rubber-based foamed material in combination with the above EPDM can also be preferably used. In this case, as the rubber component other than EPDM, for example, an appropriate substance such as natural rubber, butyl rubber, chloroprene rubber, acrylic rubber, styrene / butadiene rubber or nitrile / butadiene rubber can be used. The amount of EPDM used is preferably 20% by weight or more of the total rubber component from the viewpoints of weather resistance and durability.

For the production of a foam such as EPDM which satisfies the conditions of the present invention, for example, a mixture obtained by mixing a rubber component with an appropriate additive such as a foaming agent or a vulcanizing agent is molded into a sheet or the like and foamed. After the sulfur treatment, a part or all of the cells may be subjected to a physical property adjusting treatment such as breaking the cells by an appropriate means such as a compression treatment, or the like.

Examples of the foaming agent include azodicarbonamide, dinitrosopentamethylenetetramine, azo series such as sodium hydrogen carbonate and 4,4'-oxybis (benzenesulfonyl semicarbazide), N-nitroso series, inorganic series and semicarbazide. A suitable system such as a hydrazine system or a triazole system can be used. The amount of the foaming agent used is preferably 5 to 50 parts by weight per 100 parts by weight of the rubber component from the viewpoint of the expansion ratio for obtaining the desired physical properties.

As the vulcanizing agent, sulfur, P-quinonedioxime, P, P'-dibenzoylquinonedioxime, 4,4'-dithiodimorpholine, P-dinitrosobenzine, ammonium benzoate, N, Appropriate ones such as N'-m-phenylenedimaleimide may be used. The amount of the vulcanizing agent to be used is preferably 1 to 30 parts by weight per 100 parts by weight of the rubber component in view of obtaining desired physical properties while preventing foaming inhibition such as insufficient vulcanization and gas escape.

In preparing the above-mentioned admixture, a suitable foaming aid such as urea-based, salicylic acid-based or benzoic acid-based, aldehyde ammonia-based or aldehyde amine-based, thiourea-based or guanidine-based, thiazole-based or sulfenamide-based An appropriate vulcanization aid such as a system, a thiuram system, a dithiocarbamate system, or a xanthate system may be used if necessary.

Further, for example, fillers made of calcium carbonate, talc, clay, mica powder, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, metal oxides such as aluminum oxide and zinc oxide, paraffins and naphthenes. Additives such as a softening agent of a system, an aroma system, an asphalt system, etc. can be blended as necessary in preparing the mixture.

In the above, the amount of the filler used is 3 per 100 parts by weight of the rubber component from the viewpoint of controlling physical properties such as strength.
0 to 300 parts by weight is preferable. The amount of softener used is
10 to 100 parts by weight of the rubber component from the viewpoints of adjusting the viscosity of the mixture related to foamability and preventing blooming.
300 parts by weight is preferred.

As the above-mentioned EPDM-based foam used in the present invention, for example, 0.5 to 50 of the mixture is placed on a release liner.
Unfolded with a thickness of mm, 1 at a temperature of 100-200 ℃
Foaming ratio 3 to 30 by heat treatment for 0 to 60 minutes
It is preferable to use a foam-vulcanized product that has a foaming vulcanization ratio of 5 to 15 times, especially 8 to 13 times. If the expansion ratio is less than 3 times, the compression repulsion force is large and it may be difficult to arrange it in a narrow space. If it exceeds 30 times, it is difficult to control the characteristic impedance and satisfactory performance such as sound proofing and vibration proofing is achieved. May not be obtained.

The porous member preferably used in the present invention has a specific gravity of 0, which is made of an appropriate thermoplastic resin such as polyurethane, polyethylene or polyvinyl chloride, or an appropriate rubber polymer such as butyl rubber or isoprene rubber. 0.01 to 0.9, and more preferably 0.016 to 0.1, in particular, by impregnating an appropriate resin such as acrylic, polybutyral, or polyester into an open-cell foam to obtain the above impedance characteristics. Some of them are also included. In that case, the impregnation amount of the resin can be appropriately determined according to the characteristic impedance and the like, but is generally 0.01 to 1.0 g / c.
m ^3, are especially 0.02~0.1g / cm ³ order.

Further, in the present invention, the porous member which can be preferably used in terms of effects such as noise reduction and vibration isolation is 1.0 to
In the frequency region of 3.0 kHz, the expression: α ≧ 0.01 fneper / m is satisfied, where α is the attenuation constant and f is the frequency, and 0.02 fneper / m ≦ α ≦ 2fn
It satisfies eper / m.

Further, in the present invention, the porous member which can be preferably used from the viewpoint of the mountability in a narrow space and the like has the compressibility as exemplified above, but the compressibility is 50% when compressed. Repulsive stress of 10-200g
f / cm ² , especially 20 to 150 gf / cm ² , especially 30 to 12
Those exhibiting a compression characteristic of 0 gf / cm ² are particularly preferred.

The form of the porous member, and thus the form of the vibration reducing material, can be appropriately determined according to the purpose of use such as the application site, and the thickness thereof is also arbitrary. Generally, 100 mm or less based on apparent thickness, especially 0.5-70 mm, especially 1-
It is a 40 mm thick porous member or vibration reducing material.
The porous member or the vibration reducing material does not have to have a uniform thickness, and the thickness may be partially different.

The porous member having a partially different wall thickness, and thus the vibration reducing material, has a predetermined size, for example, by applying an adhesive to the surface of a chip produced by crushing the porous member into flakes. It can be efficiently formed by a method of filling the mold with the above and compression molding.

As described above, the film layer is intended to improve the sound insulation property, the vibration propagation prevention property, and the mounting workability. In other words, the film layer improves the soundproofing and antivibration performance by blocking noise such as sound generated inside the device and reducing the leakage and propagation to the outside, and further improving the soundproofing and antivibration performance. Reinforcing the decrease in self-supporting property due to thin layer of quality material,
Prevents the occurrence of mounting troubles such as bending and improves the operability and efficiency of the mounting work, and suppresses the variation in performance such as soundproofing and anti-vibration due to the variation of mounting state and the deterioration of work efficiency due to the mounting mistake. It dramatically improves workability and makes it possible to efficiently achieve advanced and uniform processing such as soundproofing and antivibration.

The film layer can be provided on a part or all of one side or both sides of the porous member, and may be provided in an enclosed form including all or a part of the side surface of the porous member. The film layer can be attached by an appropriate method such as an adhesive method using a film adhesive or a pressure-sensitive adhesive, a heat fusion method, and a film layer forming method by coating a polymer solution. In that case, the film layer may be partially bonded to the porous member, and for example, in the case of a porous member having a different wall thickness, it is not necessary to completely bond the film layer.

The film layer can be formed of an appropriate polymer such as those exemplified for the above-mentioned porous member, and the kind thereof is not particularly limited. Generally, for example, polyester-based or polyolefin-based polymers such as polyethylene and polypropylene, polyamide-based or polyimide-based, polystyrene-based, vinyl chloride-based, or fluorine-based polymers are used. From the viewpoint of mounting workability and the like, those having excellent slipperiness and the like are preferable. Further, from the viewpoints of processability and prevention of harmful gas during heating, polyester-based polymers are preferable.

A film layer which is preferable from the viewpoint of sound insulation and vibration propagation prevention for the purpose of improving the effects of soundproofing and antivibration has a ventilation rate of 2.039 × 1/10 ⁴ mmH ₂ O at atmospheric pressure. It is less than 0.01 cc / cm ² / sec based on the difference. Further, the film layer may contain the additives and the like exemplified in the above-mentioned porous member for an appropriate purpose, but the increase in weight due to the inclusion thereof is a property of preventing sound leakage and vibration propagation due to sound insulation and vibration damping action. It is effective for improving

In the case of the vibration reducing material in which the film layers are provided on both sides of the porous member, vibration such as sound does not enter the porous member due to the above-mentioned sound insulation and vibration damping effect, so that soundproofing or vibration damping effect is not exhibited. However, the film layer on the side of the oscillation source such as a noise source is such that its existence can be neglected according to the mass law, and it vibrates integrally with the oscillation source and thus vibrates integrally. Substantially unlikely to affect the effects.

Therefore, in the case of the vibration reducing material having the film layer on only one surface of the porous member, either the front surface or the back surface may be arranged as the oscillation source side. In general, the side not having the film layer 22 as shown in FIG. 1 is arranged as the oscillation source (1) side. The film layer on the oscillation source side may be subjected to appropriate sound insulation and vibration propagation inhibiting properties such as thinning and perforation to make it porous.

The thickness of the film layer is not particularly limited and can be appropriately determined. Generally, it is 5 to 200 μm, especially 8 to 15 from the viewpoint of reinforcement effect and thinning of vibration reducing material.
The thickness is 0 μm, especially 25 to 125 μm. When film layers are provided on the front and back of the porous member, the material and thickness of the film layers may be the same or different.

The vibration reducing material according to the present invention is formed in advance in a predetermined shape, for example, and is disposed between various members such as between the HDD main body 1 and the substrate 3 as shown in FIG. For example, sound-insulating material, sound-absorbing material, or sound-insulating material, such as a method of filling and arranging in a space such as DVDD or CDD, or a method of attaching a tape-shaped or sheet-shaped material by an appropriate method such as a winding method or a sticking method. Materials, vibration damping materials and vibration damping materials,
Alternatively, it can be preferably used as a composite functional material or the like for various types of vibration propagation reduction processing according to the related art.

In particular, like the HDD, CDD, DVDD, or tape recorder, an information recording device for recording or reproducing optical or magnetic information via an information recording medium such as a disk or a magnetic tape and its driving mechanism. It can be preferably used as a device-mounting type for equipment.

[0034]

EXAMPLES Examples 1 and 2 60 mol% of ethylene, 10 mol% of propylene, 30 mol% of polyene, 100 parts of EPDM of Mooney viscosity ML _{1 + 2} (100 ° C.) 65 (parts by weight, the same applies hereinafter), heavy calcium carbonate 200 parts, paraffin oil 50 parts, ADCA
10 parts of organic foaming agent and 2.5 parts of sulfur were kneaded with a kneader and spread on a release liner with a thickness of 10 mm to obtain 16
After foaming and vulcanization by heating at 0 ° C for 30 minutes, a closed-cell foam having a foaming ratio of 6 times was passed through rolls with a gap of 1/3 of the foam thickness, and then a thickness of 2 mm. A porous member was obtained by slicing into pieces, and a PET film having a thickness of 38 μm was adhered to one surface of the porous member via an adhesive layer to obtain a vibration reducing material.

With respect to the porous member obtained above, 1.0 to 3.
When the absolute value (Zc) of the characteristic impedance in the frequency range of 0 kHz was examined, it was 3.5 × 10 ³ kg / m ² · S
Met.

Example 3 A vibration reducing material was obtained in the same manner as in Example 1 except that PET films were provided on both sides.

Example 4 DPT-based organic foaming agent 2 was used in place of ADCA-based organic foaming agent.
A closed-cell foam having a foaming ratio of 20 times was obtained in the same manner as in Example 1 except that 5 parts were used, and the gap was passed between rolls having a gap of 1/3 of the foam thickness, and then a thickness of 2 mm. Slice it
A vibration reducing material was obtained in the same manner as in Example 1 except that a porous member having Zc of 1.7 × 10 ³ kg / m ² · S was obtained and used.

Example 5 A polyester type urethane foam having a specific gravity of 0.055 and an average cell diameter of 0.37 mm was formed and sliced into a thickness of 2 mm to have a Zc of 1.1 × 10 ³ kg. A vibration reducing material was obtained in the same manner as in Example 1 except that a porous member having a diameter of / m ² · S was obtained and used.

Comparative Example 1 The porous member obtained in Example 1 was used as it was as a vibration reducing material.

Comparative Example 2 The porous member obtained in Example 4 was used as it was as a vibration reducing material.

Comparative Example 3 The porous member obtained in Example 5 was used as a vibration reducing material as it was.

Evaluation test Attenuation constant α With respect to the porous member (vibration reducing material) obtained in the example (comparative example), an attenuation constant in a frequency range of 1.0 to 3.0 kHz was measured by a 2 microphone acoustic impedance measuring device. I checked.

Repulsion force The vibration reducing materials obtained in Examples and Comparative Examples were compressed to a thickness of 50% at a speed of 100 mm / min, and the repulsion force after 10 seconds was examined.

Sound Reduction Amount As shown in FIG. 2, the vibration reducing materials obtained in Examples and Comparative Examples are installed between the HDD body and the substrate, and the 42 is placed on a stand 41 provided in a silent room. Drive through the drive source 44,
A microphone 43 is placed at a position 300 mm (d) above the device 42, and sound is measured through an analyzer 45, and the amount of noise reduction at the A characteristic overall value is checked based on the sound level when there is no vibration reducing material. It was Note that the film layer was arranged on the substrate side in principle, but in Example 2, HD
It was placed on the D side.

Handleability In the above, the handleability during the mounting work of the vibration reducing material was evaluated.

The above results are shown in Tables 1 and 2. The damping constant is 1.0 kHz or 3.0 kHz, but the damping constant in the intermediate frequency range is
It was an intermediate value between 1.0 kHz and 3.0 kHz.

[Table 1]

[0047]

[Table 2]

[Brief description of drawings]

FIG. 1 is a sectional view of an application example.

[Fig.2] Explanatory diagram of sound measurement test

[Explanation of symbols]

1: HDD body 2: Vibration reduction material 21: Porous member 22: Film layer 3: substrate

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideyuki Kitai             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. (72) Inventor Yasunori Sugihara             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. (72) Inventor Manabu Matsunaga             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. F term (reference) 3J048 AC03 BD01 BD02 BD04 DA10                       EA07                 4F100 AA08 AK04B AK12B AK15B                       AK41B AK42 AK46B AK49B                       AK75 AR00A AT00B BA02                       BA03 BA10A BA10B CA23                       CB05 DG06A DJ01A DJ02                       GB41 JH01 JH02 YY00A                 5D061 AA07 AA22 AA26 AA40 BB24                       DD02 DD03 DD11

Claims (4)

[Claims] 1. A vibration characterized by having a film layer on one or both sides of a porous member having an absolute value of characteristic impedance of 800 kg / m ² · S or more in a frequency range of 1.0 to 3.0 kHz. Reduction material. 2. The porous member according to claim 1, wherein the porous member is 1.0
A vibration reducing material satisfying the formula: α ≧ 0.01f neper / m, where α is the damping constant and f is the frequency in the frequency region of up to 3.0 kHz. 3. The vibration reducing material according to claim 1, wherein the porous member has a repulsive stress of 10 to 200 gf / cm ² at 50% compression. 4. The vibration reducing material according to claim 1, wherein the film layer is made of polyester, polyethylene, polyamide, polyimide, polystyrene or vinyl chloride polymer and has a thickness of 5 to 200 μm.