JP3447643B2 - 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]

[Means for Solving the Problems]

The high damping rubber composition of the present invention contains 100 parts by weight of a rubber containing natural rubber and butyl rubber.
A high damping rubber composition containing 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, wherein the weight ratio of carbon black and silica is 75/25 to 25/75. By doing so, the above object is achieved.

In one embodiment, the characteristics 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.

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

[0012] 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, DBP oil absorption is 60ml / 100g or more.

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.

Note that the general carbon black referred to here is
Ku is a nitrogen adsorption specific surface area of 100 m ²/ G or less, DBP
Oil absorption range of 40-140 ml / 100g, and fine particles
Carbon black is a nitrogen adsorption specific surface area of 100 to 15
0m²/ G, DBP oil absorption 60-160ml / 100g
The range of.

Further, when a large amount of silica is added, the damping property can be enhanced at the time of small deformation and large deformation (for example, 200% deformation) of the high damping rubber, but the elongation becomes small and the workability also deteriorates.

Since the compounding of the resin can enhance the damping property of the highly damped rubber, the compounding amount is selected in consideration of the processability and temperature dependency.

When a large amount of resin is added to the rubber composition, the damping property of the high damping rubber is increased, but the workability is deteriorated due to adhesion. Blending a large amount of resin also reduces the temperature dependence.

Butyl rubber can enhance 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 are hardly changed.

[0021]

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, it further contains other rubber. The rubber may be composed of natural rubber and other rubbers, or may be blended with other polymer components.

When the rubber is composed of natural rubber and other rubber, the amount of the other rubber is preferably 10 to 50 parts by weight, more preferably 60 to 80 parts by weight of the natural rubber, relative to 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 the natural rubber, it is possible to further improve the damping while maintaining the temperature dependence.

The other rubbers mentioned above are isoprene rubber,
Examples thereof include butadiene rubber, styrene / butadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, butyl rubber, ethylene / propylene rubber, epichlorohydrin rubber, silicone rubber, fluororubber and urethane rubber. Another particularly preferred rubber is butyl rubber. Further, two or more kinds of other rubbers may be used together.

The rubber used in the present invention may contain, in addition to natural rubber and other rubbers, a thermoplastic elastomer or liquid rubber as another polymer component. In this case, the thermoplastic elastomer is 1 to 3 in the rubber.
0 wt% may be blended.

(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, more 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 kind or a plurality of kinds of carbon black may be used. The characteristics of the carbon black mainly used are as follows.

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

The carbon black has a DBP oil absorption of 60 to 160 ml / 100 g, particularly 100 to 100 ml.
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 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 damping property of the high damping rubber is inferior, 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 rubber is used. The elongation at break 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 100 m ² / g, the damping property at the time of large deformation decreases.

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. 160 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 generally 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.

Therefore, in the rubber composition of the present invention, it is preferable to add 50 to 150 parts by weight, more preferably 70 to 100 parts by weight, of the above-mentioned carbon black and silica in total with respect to 100 parts by weight of 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 25 to 75 parts by weight of silica to 75 to 25 parts by weight of carbon black, and more preferably 25 to 75 parts by weight of carbon black.
˜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).

[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 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 4 and Comparative Examples 1 to 3) Table 1
Rubber, carbon black, silica (white carbon) and petroleum resin (C9 petroleum resin) are blended in the blending ratio shown in, and a vulcanization accelerator, a vulcanizing agent, and other additives are added to 100 parts by weight of the rubber. Add an appropriate amount of the agent,
An unvulcanized rubber composition was prepared.

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) 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]

From these results, the following can be seen.

When a large amount of 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 2 and Example 1).

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

Butyl rubber as another rubber can have a high damping property, and does not deteriorate the temperature dependency so much as compared with the improvement of the damping property (comparison between Example 1 and Comparative Example 3).

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

The synergistic effect of natural rubber, butyl rubber, carbon black, silica and resin makes it possible to increase the damping rate at the time of 200% deformation.

[0056]

According to the present invention, since a specific rubber component and carbon black of fine particles are used and silica is blended, the damping property can be enhanced without lowering the temperature dependence and mechanical properties. Therefore, it can be suitably used as a high-damping rubber composition for absorbing various vibration energy such as vibration and vibration control for automobiles and various machines, seismic isolation for earthquakes, and other vibration control and vibration control.

[Brief description of 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]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C08L 23:22 C08L 57:02 57:02) (56) References JP-A-11-153168 (JP, A) JP-A-13 / 187826 (JP, A) International Publication 98/016580 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 7/00 C08K 3/04 C08K 3/36 C08L 23/22

Claims (5)

(57) [Claims] 1. 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 75
/ 25 to 25/75 high damping rubber composition. 2. The high damping rubber composition according to claim 1 , wherein the characteristics of the carbon black satisfy the following: The nitrogen adsorption specific surface area of the carbon black is 100 to 150.
m ² / g, carbon black DBP oil absorption is 60 to 160 ml /
100 g. 3. The silica has an average particle diameter of 1 to 50 μm.
The high damping rubber composition according to claim 1 or 2 . 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 100 to 150.
m ² / g, carbon black DBP oil absorption is 60 to 160 ml /
100 g. 5. 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 based on parts by weight.