JP3447641B2 - High damping rubber composition - Google Patents

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 specifically, to vibration and vibration control of automobiles, various machines and the like, seismic isolation and other vibration control,
The present invention relates to a high damping rubber composition for absorbing various vibrational energy such as vibration damping.

[0002]

2. Description of the Related Art Devices and machines that absorb various types of vibrational energy such as seismic isolation and other vibration control and vibration control have been attracting attention. The 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 damping rubber composition forming the rubber layer 2 is
Main component is natural rubber with excellent mechanical properties, and acrylonitrile butadiene rubber and high styrene compound SBR
Attenuation characteristics of vibration energy are obtained by blending rubber and the like.

For example, Japanese Patent Laid-Open No. 7-126437,
Japanese Patent Publication No. 2949671 discloses a high damping rubber composition containing natural rubber and synthetic isoprene rubber as rubber components. Further, JP-A No. 11-158324 discloses a rubber composition containing a diene rubber.

However, the high damping rubber composition has not only damping characteristics but also cold resistance, fracture resistance, long-term stability of performance,
Properties such as workability are required, and in the above rubber composition, there is a problem that, for example, if the attenuation rate of the rubber composition is increased, the cold resistance decreases (temperature dependency increases).

By blending natural rubber with a large amount of carbon black having a small particle size or by incorporating silica,
Some try to obtain high damping characteristics. For example, Japanese Patent Publication No. 2762407 discloses a high damping rubber composition containing rubber containing natural rubber as a main component, 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 Japanese Patent Publication No. 294967.
No. 1 contains 5 natural rubber and / or isoprene rubber.
100 parts by weight of rubber containing 0 part by weight or more, 15 to 60 parts by weight of petroleum resin, 60 to 95 parts by weight of fine particle carbon black and silica, and a weight part ratio of fine particles of carbon black and silica of 95/5 to 75. A high damping rubber composition in the range of / 25 is disclosed, and it is stated that a low elastic modulus can be obtained without reducing the damping property by using silica by replacing a part of carbon black. However, even with this rubber composition, the damping 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 mechanical characteristics without causing a small deformation. And during large deformation (for example, 200% deformation)
To provide a high-damping rubber composition which has a high damping property and does not deteriorate workability.

[0008]

A high damping rubber composition according to claim 1 is a 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 and silica is 95/5.
25/75, a high damping rubber composition having a nitrogen adsorption specific surface area of 200 to 300 m ^{2 of the} carbon black.
/ G, DBP oil absorption of carbon black is 60ml / 1
It is not less than 00 g, and thereby the above object is achieved.

The high damping rubber composition according to claim 2 has a total of 50 to 150 of carbon black and silica based on 100 parts by weight of rubber containing natural rubber and butyl rubber.
And 10 to 50 parts by weight of petroleum resin, and the weight ratio of carbon black and silica is 95/5 to 25/75.
Which has a nitrogen adsorption specific surface area of 200 to 300 m ² / g and a DBP oil absorption of carbon black of 60 ml / 100 g or more, thereby achieving the above object. It

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

In one embodiment, the carbon black is a plurality of kinds, and the characteristics 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 and carbon black. DBP oil absorption of 60ml / 100g or more.

[0012] In one embodiment, the weight ratio of carbon black and silica is 75/25 to 50/50.
Is.

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 blended with a rubber composition, the damping property of the high damping rubber at the time of small deformation is increased, but the hardening of the rubber is accelerated, so that the damping property at the time of large deformation is insufficient. To do. When a large amount of fine particle carbon black is blended, compared to general carbon black,
Although the damping property of the high damping rubber is high, the damping property at the time of large deformation is also insufficient.

Further, when a large amount of resin is blended in the rubber composition, the damping property of the high damping rubber is increased, but the workability is deteriorated due to sticking. Blending a large amount of resin also reduces the temperature dependence.

When a large amount of silica is added to the rubber composition,
Although it is possible to increase the damping of the high damping rubber during large deformation, the workability is deteriorated. Note that the general carbon black referred to here is a nitrogen adsorption specific surface area of 100 or less, DB
The P oil absorption range of 40 to 140 and the particulate carbon black refer to the nitrogen adsorption specific surface area of 100 to 150 and the DBP oil absorption range of 60 to 150.

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

By blending the ultrafine particulate carbon black having a smaller particle size than the particulate carbon black as described in claim 1 into the rubber composition, the damping property of the high damping rubber at the time of large deformation with a small amount of blending can be obtained. Can be higher. Further, the elongation at break can be increased by using the ultrafine carbon black. However, if too much ultrafine carbon black is blended, the temperature dependence will be 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 enhance the damping property of the high-damping rubber, an appropriate amount is compounded in consideration of processability and temperature dependence.

Butyl rubber can enhance the damping property of the high damping rubber, and does not deteriorate the temperature dependence as much as when other rubber components are blended. Further, even if the natural rubber is replaced with isoprene rubber, the physical properties are hardly changed.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION (Rubber) The rubber base material (unvulcanized rubber) used in the high damping rubber composition of the present invention contains natural rubber (or isoprene rubber, hereinafter referred to as natural rubber) as a main component. In addition, butyl rubber having a small temperature dependency may be contained. The rubber may be composed of natural rubber and butyl rubber, or may be blended with other rubber.

When the rubber is composed of natural rubber and butyl rubber, 10 to 50 parts by weight of butyl rubber is preferable to 50 to 90 parts by weight of natural rubber, and more preferably 20 to butyl rubber to 60 to 80 parts by weight of natural rubber. ~ 40 parts by weight. By adding an appropriate amount of butyl rubber to the natural rubber, it is possible to further improve the damping while maintaining the temperature dependence.

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

Other rubber (unvulcanized rubber) that can be compounded in addition to natural rubber or butyl rubber is butadiene rubber,
Styrene / butadiene copolymer rubber, acrylonitrile /
Examples include unvulcanized rubber such as butadiene copolymer rubber, halogenated butyl rubber and chloroprene rubber, and thermoplastic elastomers having a sufficiently low elastic modulus at around room temperature.

(Petroleum Resin) The petroleum resin blended in the rubber composition of the present invention means C5 petroleum resin, C9 petroleum resin,
Included are alicyclic petroleum resins and copolymers of C5 and C9.

The petroleum resin is blended in an amount of 10 to 50 parts by weight, preferably 10 parts by weight, based on 100 parts by weight of the total rubber.
~ 30 parts by weight. When the amount of the petroleum resin is less than 10 parts by weight, the damping property of the high damping rubber is insufficient, and when it exceeds 50 parts by weight, the processability of the rubber composition is deteriorated, which is not preferable.

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

In the present invention, one or a plurality of types of carbon black may be used, but the characteristics of the carbon black mainly used 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, and particularly 60 to 150.
ml / 100g is preferred.

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 Co., Ltd.), and carbon black # 8500 (manufactured by Tokai Carbon Co., Ltd.) are commercially available.

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

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

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

A smaller DBP oil absorption of carbon black is more advantageous in terms of hysteresis loss and elongation at break of the rubber material, but if it is less than 60 ml / 100 g, dispersibility in the rubber composition will be poor. 150 ml / 100 g
When it exceeds, the rubber material has insufficient hysteresis loss and insufficient elongation at break.

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

White carbon is also called finely divided silica, and may be any of finely divided silicic acid anhydride, hydrous 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. Specific examples thereof include Nipseal manufactured by Nippon Silica Co., Ltd. and Tokuseal manufactured by Tokuyama Soda Co., Ltd.

By using the ultrafine carbon black as described above, the damping property at the time of large deformation can be enhanced with a small amount of compounding. Also, the breaking elongation can be increased.

Therefore, in the rubber composition of the present invention, the total amount of the above carbon black and silica is preferably 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 will be insufficient, and if it exceeds 150 parts by weight, the workability and the elongation of the obtained high damping rubber will be reduced, which is not preferable.

The weight ratio of carbon black to silica is preferably 5 to 75 parts by weight of silica to 95 to 25 parts by weight of carbon black, and more preferably 25 to silica of 75 to 50 parts by weight of carbon black. ~
It is 50 parts by weight.

(Additives, etc.) In producing the high damping rubber composition (vulcanized rubber composition) of the present invention, in addition to the above-mentioned components, a vulcanizing agent such as sulfur, zinc white, and stearin are added to the unvulcanized rubber. Vulcanization aids such as acids, vulcanization accelerators, vulcanization retarders, antioxidants, softeners (process oil, etc.), plasticizers, tackifiers, resins, and other additives are not added if necessary. It can be added to vulcanized rubber.

The high-damping rubber composition (unvulcanized rubber composition) containing these compounding agents is appropriately molded, and by using a method and an apparatus known per se, 110 ° C. to 17 ° C.
It is vulcanized at 0 ° C. to obtain a high damping 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 number, the more difficult it is to break. (2) Breaking elongation (EB) (%) Measured according to JIS K6251. The larger the number, the greater the growth. (3) Rigidity at 200% Deformation The test piece 4 shown in FIG. 2 was prepared, and the rigidity at 20 ° C. when the shear test was performed at a frequency of 0.3 Hz, the deformation amount was about 200% with respect to the rubber thickness, was obtained. It was (4) Attenuation rate at 200% deformation (heq%) With the test piece 4 shown in FIG. 2, the attenuation rate heq (%) at 200% deformation was calculated by a known method. In the figure, reference numeral 5 represents a high damping rubber made of the high damping rubber composition of the test piece 4. (5) Temperature dependence 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 amount was about 200% with respect to the rubber thickness, and the ratio of the elastic moduli at −10 ° C. and 20 ° C. when the shear test was performed. Seeking
The temperature dependence 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 blended at the blending ratio shown in Table 1, and 100 parts by weight of rubber was further added. On the other hand, a vulcanization accelerator, a vulcanizing agent, and other additives were mixed in appropriate amounts to prepare an unvulcanized rubber composition.

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

The physical properties of the carbon black used 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 (Showa Cabot) Nitrogen adsorption specific surface area: 111 m ² / g DBP oil absorption: 115 ml / 100 g Carbon black (3) Product name: N219 (Showa Cabot) Nitrogen adsorption specific surface area: 104 m ² / g DBP oil absorption: 78 ml / 100 g The results of the above Examples and Comparative Examples are shown in Table 1.

[0050]

[Table 1]

From these results, the following can be seen.

By using ultrafine carbon black having a smaller particle size than that of fine carbon black, the damping property at the time of large deformation can be enhanced with a small amount of compound (Comparative Examples 2 and 3 and Example 1). comparison).

By using ultrafine carbon black, the breaking elongation 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 dependence becomes worse (Comparative Example 1).

When a large amount of silica is added, the damping property can be increased, but the elongation becomes small and the workability deteriorates (comparison between Comparative Example 4 and Example 1).

Since the resin can have a high damping property,
Consider the temperature dependence and mix in an appropriate amount.

Butyl rubber can have a high damping property, and the temperature dependency is not so bad as compared with the improvement of the damping property (comparison between Example 1 and Example 5).

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

[0059]

EFFECTS OF THE INVENTION According to the present invention, a specific rubber component and ultrafine carbon black are used, and silica is blended, so that the damping property is enhanced without lowering the temperature dependence and mechanical properties. Vibration prevention, vibration control, and seismic isolation for earthquakes,
It can be suitably used as a high-damping rubber composition for absorbing various vibrational energy such as vibration damping and vibration damping.

[Brief description of 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]

1 Seismic isolation rubber device 2 rubber layers 3 hard plate 4 test pieces 5 High damping rubber

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References International Publication 98/016580 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 7/00 C08K 3/04 C08K 3/36

Claims (6)

(57) [Claims] 1. A 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 and silica is 95/5.
25/75 , the carbon black having a nitrogen adsorption specific surface area of 200 to 30.
0 m ² / g, DBP oil absorption of carbon black is 60 ml / 100 g
The above is a 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 are added to 100 parts by weight of rubber containing natural rubber and butyl rubber, and the weight of carbon black and silica. Ratio is 95
A high damping rubber composition of / 5 to 25/75 , wherein the carbon black has a nitrogen adsorption specific surface area of 200 to 30.
0 m ² / g, DBP oil absorption of carbon black is 60 ml / 100 g
The above is a high damping rubber composition. 3. The average particle size of the silica is 1 to 50 μm.
The high damping rubber composition according to claim 1 or 2, wherein the high damping rubber composition is m. 4. The carbon black is a plurality of types,
The high damping rubber composition according to any one of claims 1 to 3, wherein the characteristics of the main component, carbon black, satisfy the following: The nitrogen adsorption specific surface area of carbon black is 200 to 300.
m ² / g, carbon black DBP oil absorption is 60 ml / 100 g
that's all. 5. The high damping rubber composition according to claim 1, wherein the weight ratio of the carbon black and silica is 75/25 to 50/50. 6. The rubber 100 has a content of silica.
The high damping rubber composition according to claim 1, which is 40 parts by weight or less with respect to parts by weight.