JP2000239441A - High damping rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition showing less temperature-dependent and high damping ratio of vibration energy (heq) by mixing butyl rubber as a material which maintains small temperature dependence and increases damping ratio with natural rubber as a basic material. SOLUTION: An amount of butyl rubber to be mixed with natural rubber is preferably not more than 50 pts.wt per 100 pts.wt. of a sum of the natural rubber and the butyl rubber. About 5-50 pts.wt. of a 9C-based hydrocarbon resin as a damping improver having a softening point of not more than 120 deg.C may be mixed with 100 pts.wt. of the sum of the natural rubber and the butyl rubber. The rubber composition is prepared by masticating each component by means of intermixing followed by simultaneously, adding fillers, mixing thereof uniformly and kneading a vulcanization accelerator and a vulcanization agent. The filler may be localized in the butyl rubber. It is possible to maintain small temperature dependence and increase damping ratio by localizing the filler in the butyl rubber of the compound in which the natural rubber contains the butyl rubber.

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 for absorbing various vibrational energies such as seismic isolation against vibration and other vibration proofing / damping.

[0002]

2. Description of the Related Art In recent years, devices and machines that absorb various vibration energies, such as seismic isolation against earthquakes and other vibration proofing / damping, have attracted attention.

As an effective means for absorbing vibrational energy, high damping rubber compositions have been spotlighted. The conventional high damping rubber composition is composed mainly of natural rubber having excellent mechanical properties, and a highly polar high styrene compounded S
By blending BR rubber or the like, a damping characteristic of vibration energy has been obtained.

[0004] However, the conventional high damping rubber composition has a problem that when the damping rate heq is increased, the temperature dependency is considerably increased. It is preferable to use a material having as high an attenuation rate heq as possible and having a small temperature dependency.

[0005] In addition, there is an attempt to obtain high damping characteristics by blending a large amount of carbon black having a fine particle diameter into natural rubber, but this also increases the temperature dependence of the elastic modulus.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-damping rubber composition having a higher damping rate heq of vibration energy and a lower temperature dependency than conventional ones.

[0007]

In order to solve the above-mentioned problems, the present invention employs the following technical means. The high damping rubber composition of the present invention is characterized by comprising natural rubber as a base and butyl rubber as a temperature dependency maintaining / decay rate increasing agent.

[0008] Since the high damping rubber composition employs the above-described structure, the damping rate can be further increased even if the temperature dependency is substantially the same as that of the conventional one. C9 having a softening point of 120 ° C. or less based on 100 parts by weight of the total of the natural rubber and the butyl rubber as an attenuation rate increasing agent
About 5 to 50 parts by weight of the hydrocarbon resin may be blended.

When butyl rubber is provided as an agent for maintaining the temperature dependency and increasing the damping rate, the compounding ratio of the C9 hydrocarbon resin having a softening point of about 120 ° C. or less is about 5 to 5%.
By adding 0 parts by weight, the damping rate of the rubber composition can be sufficiently improved. It is preferable to add a small amount of C9-based hydrocarbon resin from the viewpoint of processability in order to increase tackiness. In addition to natural rubber and butyl rubber, reinforcing agents (carbon black, silica), softeners, process oils, plasticizers,
Tackifiers, antioxidants, vulcanizing agents, vulcanization accelerators, vulcanization retarders, resins and other additives can be added as needed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A high-damping rubber composition was prepared as follows.

In Examples 1 to 9, the following components were mixed using an intermix, rubber was masticated, and then a filler was simultaneously added and uniformly kneaded. Thereafter, the vulcanization accelerator and the vulcanizing agent were kneaded with a roll.

The filler may be unevenly distributed in the butyl rubber. With the same blend of natural rubber and butyl rubber,
When the filler is unevenly distributed in the butyl rubber, the attenuation can be further improved while maintaining the temperature dependency.

[0013]

EXAMPLES Table 1 shows the formulations of Examples 1 to 9 and Comparative Examples 1 to 5
Is shown in Table 2.

[0014]

[Table 1] In Table 1, butyl rubber 1 is JSR manufactured by Nippon Synthetic Rubber Co., Ltd.
Butyl 065, butyl rubber 2 was JSR Butyl 268 manufactured by Nippon Synthetic Rubber Co., Ltd., butyl rubber 3 was JSR Butyl 365 manufactured by Nippon Synthetic Rubber Co., Ltd.
0 is represented.

[0015]

[Table 2] In Table 2, BR01 is a butadiene product manufactured by Nippon Synthetic Rubber Co., Ltd.
Rubber, JSR1503 indicates styrene-butadiene rubber manufactured by Japan Synthetic Rubber Co., Ltd., E-SBR 9550 indicates styrene-butadiene rubber manufactured by Zeon Corporation, and high styrene SBR 2057SS indicates high styrene SBR manufactured by Zeon Corporation.

Next, the following measurements were performed using each of the above samples.

Hardness (JIS.A), tensile strength (Kgf / c)
m ² ), elongation at break (%), static shear modulus (Kgf / cm ² )
To JIS. It measured according to K-6301. The test sample shown in FIG. 1 was prepared, the frequency was 0.5 Hz, the amount of deformation was about 100% with respect to the rubber thickness, and the shear test was -1.
The elastic modulus ratio at 0 ° C. and 20 ° C. was determined, and the temperature dependence of elasticity (−10 ° C./20° C.) was calculated. In the drawing, the sample high damping rubber composition is indicated by 1. The damping rate heq (%) at the time of 150% deformation was calculated from the test sample shown in FIG. 1 by a known method.

Table 3 shows the measurement results of the examples, and Table 4 shows the measurement results of the comparative examples.

[0019]

[Table 3]

[0020]

[Table 4] If the amount of butyl rubber is too large, the tensile strength and the elongation at break tend to decrease. Therefore, the blending amount of butyl rubber is more preferably about 50 parts by weight or less based on 100 parts by weight of the total of natural rubber and butyl rubber.

FIG. 2 is a graph showing the relationship between the heq (%) in Tables 3 and 4 and the temperature dependency ratio (-10 ° C./20° C.).
As shown in this graph, the high damping rubber composition of this example can increase the damping rate even with the same temperature dependency as that of the comparative example.

Examples 7 to 9 contain 5 to 30 parts of a C9 hydrocarbon resin. As shown by the straight line on the side of the example in the graph of FIG.
The relationship between eq and the temperature dependency (it is better to lie on the horizontal axis) is more preferable than the comparative example. As described above, when butyl rubber is blended with natural rubber and a C9-based hydrocarbon resin is added, a blend having a good balance between attenuation and temperature dependence is obtained.

[0023]

The present invention is configured as described above and has the following effects.

The attenuation rate of vibration energy heq
And a high damping rubber composition having high temperature dependency and low temperature dependency can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a test sample.

FIG. 2: Heq (%) and temperature dependence ratio (−10 ° C./20)
C).

[Explanation of symbols]

 1 high damping rubber composition

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Atsushi Shimoda 172 Ikezawa-cho, Yamatokoriyama-shi, Nara Pref.

Claims (2)

[Claims] 1. A high-damping rubber composition comprising natural rubber as a base and butyl rubber as a temperature-dependent maintaining / decay rate increasing agent. 2. A softening point of 120 ° C. with respect to a total of 100 parts by weight of the natural rubber and butyl rubber as an attenuation rate increasing agent.
The high damping rubber composition according to claim 1, wherein about 5 to 50 parts by weight of the following C9 hydrocarbon resin is blended.