JP2001187826A - Rubber composition having high damping capacity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition having a high damping capacity without the temperature-dependency and the mechanical properties lowered. SOLUTION: The rubber composition having a high damping capacity comprises (a) 50-150 parts by weight of a sum of carbon black and silica and (b) 10-50 parts by weight of a petroleum resin relative to 100 parts by weight of a rubber comprising natural rubber the main component, wherein the carbon black has a weight ratio of 95/5-25/75 to the silica; and the carbon black has a specific surface area by nitrogen absorption of 150 m2/g or more and has a DBP oil absorption of 60 ml/100 g or more.

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 is a rubber composition containing a natural rubber as a main component.
A total of 50 to 150 parts by weight of carbon black and silica and 10 to 50 parts by weight of petroleum resin are contained with respect to 00 parts by weight, and the weight ratio of carbon black to silica is 95/5.
25/75, wherein the carbon black has a nitrogen adsorption specific surface area of 150 m ² / g or more, and the carbon black has a DBP oil absorption of 60 ml / 10
0 g or more, whereby the above object is achieved.

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 95/5 to 25/75.
Wherein the carbon black has a nitrogen adsorption specific surface area of 150 m ² / g or more, and the carbon black has a DBP oil absorption of 60 ml / 100 g or more, thereby achieving the above object.

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: carbon black has a nitrogen adsorption specific surface area of 150 m ² / g or more; Has a DBP oil absorption of 60 ml / 100 g or more.

In one embodiment, the weight ratio of the carbon black to silica is 75/25 to 50/50.
It is.

[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.

Further, 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.

When a large amount of silica is compounded in the rubber composition,
High damping of the high damping rubber at the time of large deformation can be increased, but workability is reduced. Note that the general carbon black referred to here is a nitrogen adsorption specific surface area of 100 or less, DB
The range of the P oil absorption of 40 to 140 and the fine particle carbon black mean the range of the nitrogen adsorption specific surface area of 100 to 150 and the DBP oil absorption of 60 to 150.

On the other hand, according to the present invention, the following functions and effects are obtained.

The ultra-fine carbon black as described in claim 1, which has a smaller particle diameter than the fine carbon black, is added to the rubber composition to reduce the damping property of the high damping rubber at the time of large deformation with a small amount. Can be higher. Further, by using ultrafine carbon black, the elongation at break can be increased. However, if the ultrafine carbon black is added in a large amount, the temperature dependency ratio becomes poor.

When a large amount of silica is added, the damping property of the high-damping rubber 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.

Butyl rubber can increase the damping property of a high damping rubber, and does not deteriorate the temperature dependency as compared with the case where other rubber components are blended. Further, even if the natural rubber is replaced with isoprene rubber, the physical properties hardly change.

[0023]

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 may further contain butyl rubber having low temperature dependence. The rubber may be composed of natural rubber and butyl rubber, or may be blended with another rubber.

When the rubber is composed of natural rubber and butyl rubber, it is preferably 10 to 50 parts by weight of butyl rubber to 50 to 90 parts by weight of natural rubber, and more preferably 60 to 80 parts by weight of natural rubber. ４０40 parts by weight. By adding an appropriate amount of butyl rubber to natural rubber, attenuation can be further improved while maintaining temperature dependency.

The rubber used in the present invention may be blended with another rubber in addition to the natural rubber alone, or may be blended with another rubber in addition to the natural rubber and butyl rubber. In this case, the other rubber may be compounded in the rubber in an amount of 1 to 30% by weight.

Other rubbers (unvulcanized rubber) other than natural rubber or butyl rubber include butadiene rubber,
Styrene-butadiene copolymer rubber, acrylonitrile
Examples include unvulcanized rubbers such as butadiene copolymer rubber, halogenated butyl rubber, and chloroprene rubber, and thermoplastic elastomers having a sufficiently low elastic modulus near room temperature.

(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 amount of 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 types of carbon black may be used, but the characteristics of mainly used carbon black are as follows.

The nitrogen adsorption specific surface area of carbon black is
150 m ² / g or more, especially 200 to 300 m ² / g
Is preferred.

The DBP oil absorption of carbon black is 60 ml / 100 g or more, especially 60 to 150 g.
ml / 100 g is preferred.

More specifically, BLACK PEARLS 880 (manufactured by Cabot Specialty Chemicals, Inc.), BLA
CK PEARLS 800 (manufactured by Cabot Specialty Chemicals, Inc.), carbon black # 8300 (manufactured by Tokai Carbon), and carbon black # 8500 (manufactured by Tokai Carbon) are 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 amount of the carbon black is too small, the energy absorption capacity of the high-attenuation rubber is inferior, and if the amount of the carbon black is excessive, the processability during the production of the rubber composition deteriorates, which is not preferable in production, and the high attenuation. The elongation at break of rubber also decreases. The above physical properties of carbon black have a great influence on the damping characteristics of a rubber material (high-damping rubber).

When the nitrogen adsorption specific surface area of the carbon black is less than 150 m ² / g, the damping property at the time of large deformation is reduced.

The smaller the DBP oil absorption of carbon black, the better in terms of hysteresis loss and breaking elongation of the rubber material. However, if it is less than 60 ml / 100 g, the dispersibility in the rubber composition becomes poor. 150ml / 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.

The white carbon is also called finely divided silica, and may be any of finely divided anhydrous silicic acid, hydrated silicic acid, calcium silicate, aluminum silicate, and the like.
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.

By using the ultrafine carbon black as described above, it is possible to increase the damping property at the time of large deformation with a small amount of compounding. Further, the breaking elongation can be increased.

Accordingly, the rubber composition of the present invention preferably contains 50 to 150 parts by weight, more preferably 70 to 100 parts by weight, of the above carbon black and silica in total with respect to 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 ratio by weight of carbon black to silica is preferably from 5 to 75 parts by weight of silica to 95 to 25 parts by weight of carbon black, more preferably from 75 to 50 parts by weight of carbon black. ~
50 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 used at 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).

[0046]

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) (Kgf / cm ² ) 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 to 5 and Comparative Examples 1 to 4) Rubber, carbon black, silica (white carbon) and petroleum resin (C9 petroleum resin) were mixed at the compounding ratio shown in Table 1, and further added to 100 parts by weight of rubber. On the other hand, an appropriate amount of a vulcanization accelerator, a vulcanizing agent and other additives were blended to prepare an unvulcanized rubber composition.

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) Brand name: BLACK PEARLS 880 (manufactured by Cabot Specialty Chemicals, Inc.) Nitrogen adsorption specific surface area: 220 m ² / g DBP oil absorption: 105 ml / 100 g Carbon black (2) Brand name: N220 (Manufactured by Showa Cabot) Nitrogen adsorption specific surface area: 111 m ² / g DBP oil absorption: 115 ml / 100 g carbon black (3) Product name: N219 (manufactured by Showa Cabot) nitrogen adsorption specific surface area: 104 m ² / g DBP oil absorption: 78 ml / 100 g Table 1 shows the results of the above Examples and Comparative Examples.

[0050]

[Table 1]

The following can be understood from these results.

By using ultra-fine carbon black having a smaller particle diameter than fine-particle carbon black, it is possible to increase the damping property at the time of large deformation with a small amount of compounding (Comparative Examples 2 and 3 and Example 1). comparison).

By using ultrafine carbon black, the elongation at break of rubber can be increased (Comparative Examples 2 and 3).
And Example 1).

When a large amount of ultrafine 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 decreases and the workability deteriorates (comparison between Comparative Example 4 and Example 1).

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

The 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 Example 5).

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

[0059]

According to the present invention, since a specific rubber component and ultrafine carbon black are used and silica is blended, the damping property can be increased without lowering the temperature dependency and mechanical properties. Can be done, anti-vibration and damping against vibration of automobiles and various machines, and seismic isolation against earthquakes,
It can be suitably used as a high attenuation rubber composition for absorbing various vibration energies such as vibration proof and vibration control.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a seismic isolation bearing 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

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takahiko Yoshida 172 Ikezawa-cho, Yamatokoriyama-shi, Nara Prefecture Nita Factory F-term (reference) 4J002 AC011 AC031 AC071 AC081 AC091 AC121 BA012 BB181 DA036 DJ017 FA007 GT00

Claims (6)

[Claims] 1. Rubber 1 containing natural rubber as a main component
A total of 50 to 150 parts by weight of carbon black and silica and 10 to 50 parts by weight of petroleum resin are contained with respect to 00 parts by weight, and the weight ratio of carbon black to silica is 95/5.
25/75, wherein the carbon black has a nitrogen adsorption specific surface area of 150 m ² /
g or more, DBP oil absorption of carbon black is 60ml / 100g
The above is the high damping rubber composition. 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 95 ratio
/ 5 to 25/75, wherein the carbon black has a nitrogen adsorption specific surface area of 150 m ² /
g or more, DBP oil absorption of carbon black is 60ml / 100g
The above is the high damping rubber composition. 3. The silica has an average particle diameter of 1 to 50 μm.
The high damping rubber composition according to claim 1 or 2, wherein m is m. 4. The method according to claim 1, wherein the carbon black is of a plurality of types.
The high damping rubber composition according to any one of claims 1 to 3, 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 150 m ^2.
/ G or more, DBP oil absorption of carbon black is 60ml
/ 100g or more. 5. The high attenuation rubber composition according to claim 1, wherein the weight ratio of the carbon black to the silica is 75/25 to 50/50. 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.