JP2001206983A - High damping rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high damping rubber composition having high damping properties without lowering temperature dependence and mechanical characteristics. SOLUTION: This high damping rubber composition comprises 100 pts.wt. of a rubber composed of a natural rubber as a main component and another rubber, 50-150 pts.wt. of total of carbon black and silica and 10-50 pts.wt. of a petroleum resin and has the weight ratio of carbon black to silica of 75/25 to 25/75. The characteristics of the carbon black satisfy 100-150 m2/g nitrogen adsorption specific surface area and 60-160 ml/100 g DBP oil absorption of carbon black.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-damping rubber composition, and more particularly, to vibration damping and vibration damping of automobiles and various machines, seismic isolation against earthquakes, and other vibration damping.
The present invention relates to a high damping rubber composition for absorbing various vibration energies such as vibration damping.

[0002]

2. Description of the Related Art Attention has been paid to devices and machines that absorb various vibration energies, such as seismic isolation against earthquakes, and other types of vibration isolation and damping. A seismic isolation rubber device 1 shown in FIG. 1 is configured by laminating a rubber layer 2 and a hard plate 3 such as a steel plate. Here, the high attenuation rubber composition forming the rubber layer 2 is as follows:
SBR containing acrylonitrile butadiene rubber or high styrene as the main component
A vibration energy damping characteristic is obtained by blending rubber and the like.

[0003] For example, Japanese Patent Application Laid-Open No. 7-126437,
Patent publication 2949671 discloses a high damping rubber composition containing natural rubber and synthetic isoprene rubber as rubber components. Japanese Patent Application Laid-Open No. 11-158324 discloses a rubber composition containing a diene rubber.

[0004] However, the high damping rubber composition has not only the damping property, but also cold resistance, breaking resistance, long-term stability of performance,
Characteristics such as processability are required, and the above rubber composition has a problem that, for example, when the attenuation rate of the rubber composition is increased, cold resistance is reduced (temperature dependence is increased).

[0005] By blending a large amount of carbon black having a fine particle diameter with natural rubber or blending silica,
Some attempt to obtain high attenuation characteristics. For example, Japanese Patent Publication No. 2762407 discloses a high damping rubber composition containing a rubber mainly composed of natural rubber, a thermoplastic hydrocarbon resin, and carbon black having predetermined characteristics. However, the high damping rubber composition disclosed herein has an insufficient damping rate.

Further, the above-mentioned patent publication No. 294967
No. 1 contains 5 and 5 parts of natural rubber and / or isoprene rubber.
100 parts by weight of rubber containing not less than 0 parts by weight, 15 to 60 parts by weight of petroleum resin, 60 to 95 parts by weight of fine particle carbon black and silica, and the weight ratio of fine particle carbon black to silica is 95/5 to 75. A high damping rubber composition having a range of / 25 is disclosed, and it is stated that a low elastic modulus can be obtained without deteriorating damping property by using silica instead of carbon black. However, even with this rubber composition, the attenuation rate is insufficient.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks, and an object of the present invention is to reduce the temperature dependence and the mechanical properties without deteriorating the small deformation. And large deformation (for example, 200% deformation)
It is an object of the present invention to provide a high-damping rubber composition having a high damping property and no decrease in processability.

[0008]

The high damping rubber composition according to claim 1 comprises a natural rubber as a main component and a total of carbon black and silica with respect to 100 parts by weight of a rubber containing other rubbers. A high-damping rubber composition containing 50 to 150 parts by weight and 10 to 50 parts by weight of a petroleum resin, wherein the weight ratio of carbon black to silica is 75/25 to 25/75, thereby achieving the above object. Is done.

The high damping rubber composition according to the second aspect is characterized in that carbon black and silica are added in a total amount of 50 to 150 parts by weight based on 100 parts by weight of a rubber containing natural rubber and butyl rubber.
Parts by weight and 10 to 50 parts by weight of petroleum resin, and the weight ratio of carbon black to silica is 75/25 to 25/7.
5 is a high damping rubber composition, whereby the above object is achieved.

In one embodiment, the properties of the carbon black satisfy the following: carbon black has a nitrogen adsorption specific surface area of 100 to 150 m ² / g, and carbon black has a DBP oil absorption of 60 to 160 ml / 100.
g.

[0011] In one embodiment, the silica has an average particle size of 1 to 50 µm.

In one embodiment, the carbon black is of a plurality of types, and the properties of the main component carbon black satisfy the following: the carbon black has a nitrogen adsorption specific surface area of 150 m ² / g or more; DBP oil absorption is 60ml / 100g or more.

[0013] In one embodiment, the content of the silica is 40 parts by weight or less based on 100 parts by weight of the rubber.

The operation of the present invention is as follows.

When a large amount of general carbon black is added to the rubber composition, the damping property of the high damping rubber at the time of small deformation increases, but the hardening of the rubber is accelerated, so that the damping property at the time of large deformation is insufficient. I do. When a large amount of fine carbon black is blended, compared to general carbon black,
Although high damping rubber has high damping properties, it still lacks damping properties during large deformation.

The general carbon black referred to here
Is the nitrogen adsorption specific surface area 100m ^Two/ G or less, DBP
Oil absorption range of 40-140ml / 100g, and fine particles
Carbon black is a nitrogen adsorption specific surface area of 100 to 15
0m^Two/ G, DBP oil absorption 60-160ml / 100g
Means the range.

When a large amount of silica is added, the damping property of the high-damping rubber at the time of small deformation and large deformation (for example, at the time of 200% deformation) can be increased, but the elongation is reduced and the workability is also deteriorated.

Since the compounding of the resin can increase the damping property of the high damping rubber, it is added in an appropriate amount in consideration of processability and temperature dependency.

When a large amount of resin is added to the rubber composition, the damping property of the high-damping rubber increases, but the workability decreases due to adhesion. When a large amount of resin is blended, the temperature dependency also decreases.

The butyl rubber can increase the damping property of the high damping rubber, and does not deteriorate the temperature dependency as much as when other rubber components are blended. Further, even if the natural rubber is replaced with isoprene rubber, the physical properties hardly change.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION (Rubber) The rubber substrate (unvulcanized rubber) used in the high attenuation rubber composition of the present invention contains natural rubber (or isoprene rubber, hereinafter referred to as natural rubber) as a main component. And further contains other rubber. The rubber may be composed of natural rubber and another rubber, or may be blended with other polymer components.

When the rubber is composed of natural rubber and other rubbers, the rubber is preferably used in an amount of 10 to 50 parts by weight, more preferably 60 to 80 parts by weight, based on 50 to 90 parts by weight of the natural rubber. On the other hand, other rubber 20 ~
40 parts by weight. By adding an appropriate amount of other rubber to natural rubber, the attenuation can be further improved while maintaining the temperature dependency.

The above other rubbers include isoprene rubber,
Butadiene rubber, styrene / butadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, butyl rubber, ethylene / propylene rubber, epichlorohydrin rubber, silicone rubber, fluorine rubber, urethane rubber, and the like. Another particularly preferred rubber is butyl rubber. Further, two or more kinds of other rubbers may be used in combination.

The rubber used in the present invention may contain, in addition to natural rubber and other rubbers, thermoplastic elastomers or liquid rubbers as other polymer components. In this case, the thermoplastic elastomer etc.
0% by weight may be incorporated.

(Petroleum Resin) The petroleum resin blended in the rubber composition of the present invention includes C5 petroleum resin, C9 petroleum resin,
Alicyclic petroleum resins and those obtained by copolymerizing C5 and C9 are included.

The petroleum resin is blended in an amount of 10 to 50 parts by weight, more preferably 10 to 50 parts by weight, based on 100 parts by weight of the total rubber.
-30 parts by weight. If the compounding amount of the petroleum resin is less than 10 parts by weight, the damping property of the high-damping rubber is insufficient, and if it exceeds 50 parts by weight, the processability of the rubber composition deteriorates, which is not preferable.

(Carbon Black and Silica) The rubber composition of the present invention uses both carbon black and silica.

In the present invention, one or more kinds of carbon blacks may be used, but the characteristics of mainly used carbon blacks are as follows.

The nitrogen adsorption specific surface area of carbon black is
100-150 m ² / g, especially 130-150 m ²
/ G is preferred.

The DBP oil absorption of carbon black is from 60 to 160 ml / 100 g, especially from 100 to 160 ml / 100 g.
160 ml / 100 g is preferred.

Specifically, Seast 9 (manufactured by Tokai Carbon Co., Ltd.), Show Black N219 (manufactured by Showa Cabot), Show Black N220 (manufactured by Showa Cabot)
Is commercially available.

The nitrogen specific surface area of carbon black is AST
It can be measured by the method described in MD3037-89, that is, by a method of determining the particle diameter based on the amount of nitrogen gas adsorbed.

The compounding of carbon black is indispensable for the rubber composition of the present invention to exhibit vibration energy absorbing ability. If the compounding amount of the carbon black is too small, the damping property of the high damping rubber is inferior, and if the compounding amount of the carbon black is excessive, the processability decreases during the production of the rubber composition, which is not preferable in production, The elongation at break also decreases. The above physical properties of carbon black have a great influence on the damping characteristics of a rubber material (high-damping rubber).

If the nitrogen adsorption specific surface area of the carbon black is less than 100 m ² / g, the damping property at the time of large deformation decreases.

The smaller the DBP oil absorption of carbon black, the better in terms of hysteresis loss and elongation at break of the rubber material. However, if it is less than 60 ml / 100 g, the dispersibility in the rubber composition becomes poor. 160ml / 100g
If it exceeds 300, the hysteresis loss and breaking elongation of the rubber material become insufficient.

The silica used in the present invention may be any silica generally used in rubber compositions, and may be amorphous silica such as precipitated silica or high-temperature treated silica, or crystalline silica. And carbon.

White carbon is also called finely divided silica, and may be any of finely divided anhydrous silicic acid, hydrous silicic acid, calcium silicate, aluminum silicate, etc.
There is no particular limitation.

Such silica has an average particle size of 1 to 50.
μm, particularly preferably 1 to 30 μm. Specifically, Nip Seal manufactured by Nippon Silica Co., Ltd., Tok Seal manufactured by Tokuyama Soda Co., Ltd., and the like are exemplified.

Accordingly, the rubber composition of the present invention preferably contains the carbon black and silica in a total amount of 50 to 150 parts by weight, more preferably 70 to 100 parts by weight, based on 100 parts by weight of the rubber. is there. If it is less than 50 parts by weight, the damping property of the rubber composition is insufficient, and if it exceeds 150 parts by weight, the processability and the elongation of the obtained high damping rubber are undesirably reduced.

The weight ratio of carbon black to silica is preferably 25 to 75 parts by weight of silica to 75 to 25 parts by weight of carbon black, more preferably 75 to 50 parts by weight of carbon black.
５０50 parts by weight.

(Additives) In producing the high damping rubber composition (vulcanized rubber composition) of the present invention, a vulcanizing agent such as sulfur, zinc white, stearin Vulcanization aids such as acids, vulcanization accelerators, vulcanization retarders, antioxidants, softeners (such as process oils), plasticizers, tackifiers, resins, and other additives are not added if necessary. Can be added to vulcanized rubber.

The high-damping rubber composition (unvulcanized rubber composition) containing these compounding agents is appropriately molded, and is heated to 110 ° C. to 17 ° C. by using a method and an apparatus known per se.
It is vulcanized at 0 ° C. to obtain a high attenuation rubber (vulcanized rubber).

[0043]

EXAMPLES The vulcanized rubbers obtained in the following Examples and Comparative Examples were evaluated for the physical properties shown below. The materials used are shown below. A. Evaluation method of physical properties (1) Tensile strength (TB) (MPa) Measured according to JIS K6251. The larger the value, the harder it is to break. (2) Elongation at break (EB) (%) Measured according to JIS K6251. The larger the value, the greater the elongation. (3) Rigidity at 200% Deformation A test piece 4 shown in FIG. 2 was prepared, and the stiffness at 20 ° C. when a shear test was performed at a frequency of 0.3 Hz, the amount of deformation was about 200% with respect to the rubber thickness was obtained. Was. (4) Attenuation rate at 200% deformation (heq%) Attenuation rate at 200% deformation heq (%) was calculated by a known method using test piece 4 shown in FIG. In the drawing, reference numeral 5 denotes a high attenuation rubber made of the high attenuation rubber composition of the test piece 4. (5) Temperature dependency ratio of elastic modulus at 200% deformation (−10 ° C.)
/ 20 ° C) The test piece 4 shown in FIG. 2 was prepared, the frequency was 0.3 Hz, the deformation was about 200% of the rubber thickness, and the elastic modulus ratio at −10 ° C. and 20 ° C. when a shear test was performed. ,
The temperature dependency ratio of elasticity (−10 ° C./20° C.) was calculated.

(Examples 1-4 and Comparative Examples 1-3) Table 1
The rubber, carbon black, silica (white carbon) and petroleum resin (C9 petroleum resin) are compounded at the compounding ratio shown in the following, and a vulcanization accelerator, a vulcanizing agent, and other additives are added to 100 parts by weight of rubber. Mix the appropriate amount of the agent,
An unvulcanized rubber composition was prepared.

The rubber composition was pressed at 150 ° C. for 30 minutes and vulcanized to obtain a vulcanized rubber.

The physical properties of the used carbon black are shown below.

Carbon black (1) Nitrogen adsorption specific surface area: 140 m ² / g DBP oil absorption: 118 ml / 100 g The results of the above Examples and Comparative Examples are shown in Table 1.

[0048]

[Table 1]

The following can be understood from these results.

When a large amount of carbon black is added, the temperature dependency ratio becomes worse (Comparative Example 1).

When a large amount of silica is added, the damping property can be increased, but the elongation is reduced and the workability is deteriorated (comparison between Comparative Example 2 and Example 1).

Since the resin can increase the damping property, the workability and
An appropriate amount is blended in consideration of temperature dependency.

As another rubber, butyl rubber can increase the damping property and does not make the temperature dependency much worse than the improvement in the damping property (comparison between Example 1 and Comparative Example 3).

Even if the natural rubber is replaced with isoprene rubber, the physical properties hardly change (comparison between Example 1 and Example 4).

By the synergistic effect of natural rubber, butyl rubber, carbon black, silica and resin, the damping rate at the time of 200% deformation can be increased.

[0056]

According to the present invention, a specific rubber component and fine carbon black are used, and silica is blended. Therefore, it is possible to enhance the damping property without lowering the temperature dependency and mechanical properties. It can be suitably used as a high-damping rubber composition for absorbing various vibration energies such as vibration proofing and vibration damping against vibrations of automobiles and various machines, as well as seismic isolation and other vibration proofing and vibration suppression.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a seismic isolation rubber device using high damping rubber.

FIG. 2 is an explanatory diagram of a test piece used in an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Seismic isolation rubber device 2 Rubber layer 3 Hard plate 4 Test piece 5 High attenuation rubber

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // (C08L 7/00 (C08L 7/00 21:00 21:00 57:02) 57:02) (72) Invention Person Takahiko Yoshida 172 Ikezawa-cho, Yamatokoriyama-shi, Nara Prefecture N-Terminal Company Nara Factory F-term (reference) 4J002 AC011 AC032 AC062 AC072 AC082 AC092 BA013 BB152 BB182 BD122 CH042 CK022 CP032 DA036 DJ017 FD016 FD017 GM00 GN00

Claims (6)

[Claims] 1. A rubber composition containing a natural rubber as a main component and a total of 50 to 150 parts by weight of carbon black and silica and 10 to 50 parts by weight of a petroleum resin based on 100 parts by weight of a rubber containing other rubbers. A high attenuation rubber composition wherein the weight ratio of carbon black to silica is 75/25 to 25/75. 2. A total of 50 to 150 parts by weight of carbon black and silica and 10 to 50 parts by weight of petroleum resin based on 100 parts by weight of rubber containing natural rubber and butyl rubber, and the weight of carbon black and silica The ratio is 75
/ 25 to 25/75. 3. The high damping rubber composition according to claim 1, wherein the carbon black satisfies the following characteristics: the nitrogen adsorption specific surface area of the carbon black is 100 to 150 m.
² / g, DBP oil absorption of carbon black is 60 to 16
0 ml / 100 g. 4. An average particle diameter of the silica is 1 to 50 μm.
The high damping rubber composition according to claim 1, wherein 5. The carbon black is of a plurality of types,
The high damping rubber composition according to any one of claims 1 to 4, wherein the characteristic property of the carbon black as the main component satisfies the following: The nitrogen adsorption specific surface area of the carbon black is 100 to 1.
50 m ² / g, DBP oil absorption of carbon black is 60
~ 160ml / 100g. 6. The method according to claim 1, wherein the content of the silica is 100%.
The high damping rubber composition according to any one of claims 1 to 5, wherein the amount is 40 parts by weight or less based on parts by weight.