JPH10231383A - Rubber composition for earthquake-proof laminated rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition imparted with a damping characteristics without deterioration a creep characteristic and a tensile characteristic by blending natural rubber with ethylene-propylene copolymer rubber in a specific ratio. SOLUTION: This rubber composition for earthquake-proof laminated rubber is obtained by blending (A) 50-90 PHR of natural rubber with (B) 10-50 PHR of ethylene-propylene copolymer rubber and, if necessary, (C) a reinforcing filler (e.g. carbon black), a softening agent (e.g. a wax), an antioxidant, a vulcanizing agent, a vulcanization accelerator, etc., e.g. by the use of a kneading machine such as a Banbury mixer. The composition is suitably applied to lead- containing earthquake-proof laminated rubber having flange plates, round earthquake-proof laminated rubber having flange plates, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rubber composition for a seismic isolation laminated rubber, and more particularly to a rubber composition for a seismic isolation laminated rubber having a damping property.

[0002]

2. Description of the Related Art Seismic isolation laminated rubber is installed between a building and a foundation to reduce the transmission of earthquake shaking to the building.
By attenuating the vibration of the building quickly, the damage of the building, the people inside, and the goods is reduced. The seismic isolation laminated rubber is obtained by alternately laminating several to several tens of layers of a rubber-like elastic body serving as a rubber layer and a rigid plate such as a metal plate.

A conventional rubber composition for a seismic isolation laminated rubber is provided with a damping property by blending butyl rubber (IIR), styrene butadiene rubber (SBR), and butadiene rubber (BR) with natural rubber (NR).

[0004] However, these natural rubber-II
The blend of R, SBR, and BR has a problem in that creep properties, tensile properties, and the like are inferior to those of natural rubber alone.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is intended to solve the problem. Natural rubber is blended with a specific synthetic rubber to reduce creep properties and tensile properties. It is an object of the present invention to provide a rubber composition for a seismic isolation laminated rubber which can impart damping characteristics without damping.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned conventional problems, and as a result, by blending a specific amount of natural rubber and a specific synthetic rubber, the desired seismic isolation is achieved. Succeeded in obtaining a rubber composition for laminated rubber,
The present invention has been completed. That is, the rubber composition for a seismic isolation laminated rubber of the present invention comprises natural rubber 50 to 90.
It is characterized by blending 10 to 50 PHR of ethylene propylene rubber with PHR.

[0007]

Embodiments of the present invention will be described below in detail. The rubber composition for the seismic isolation laminated rubber of the present invention,
It is characterized by blending 10 to 50 PHR of ethylene propylene rubber (EP) with 50 to 90 PHR of natural rubber (NR). If the natural rubber content is less than 50 PHR, the tensile properties deteriorate, and if it exceeds 90 PHR, the desired damping properties cannot be obtained.

In the rubber composition for a seismic isolation laminated rubber of the present invention, in addition to the rubber components of the natural rubber and ethylene propylene rubber, if necessary, carbon black as a reinforcing filler, a softener (wax, oil) ), Anti-aging agents,
Compounding agents commonly used in the rubber industry, such as a vulcanizing agent, a vulcanization accelerator, and a vulcanization accelerator, can be appropriately compounded.

The rubber composition for the seismic isolation laminated rubber of the present invention is prepared by kneading the above rubber component, the above-mentioned carbon black as a reinforcing filler to be compounded as required, the above rubber compounding agent, etc., with a kneader such as a Banbury mixer. be able to.

The rubber composition for a seismic isolation laminated rubber according to the present invention can be suitably applied to a rubber layer of a seismic isolation laminated rubber, and a rubber-like elastic body serving as a rubber layer and a rigid plate such as a metal plate are alternately provided. The seismic isolation laminated rubber laminated in several layers to several tens of layers can provide damping characteristics without lowering creep characteristics and tensile characteristics.

[0011] The present invention is characterized by the compounding composition of the rubber composition used for the seismic isolation laminated rubber, and the structure of the seismic isolation laminated rubber which has become a product by using the rubber composition is not limited at all. Not something. For example, the present invention is suitably applied to lead-containing seismic isolation rubber having a flange plate, a round seismic isolation rubber having a flange plate, and the like.

[0012]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

(Examples 1 to 4 and Comparative Examples 1 to 5) Rubber compositions for seismic isolation laminated rubber were prepared according to the composition shown in Table 1 below. For the rubber compositions of Examples 1 to 4 and Comparative Examples 1 to 5, tensile properties, compression set, and equivalent damping constant were evaluated by the following measurement methods. In addition, the compounding unit of the compounding composition in Table 1 is part by weight.

(1) Tensile properties Measured according to JIS K6301. The higher the value, the better.

(2) Compression set Measured according to JIS K6301. Compression set is an indicator of creep properties, and the unit is%. The smaller the value, the better.

(3) Equivalent damping constant A laminated rubber having a diameter of 100 mm, a rubber layer of 2 mm × 12 layers, a steel plate of 1 mm × 11 layers, and two flange plates shown in FIG. 1 was prepared, and the horizontal hysteresis characteristics of the laminated rubber were measured. From this horizontal hysteresis characteristic, an equivalent damping constant was obtained by the following calculation method. (Calculation method) The rigidity and the equivalent damping constant were calculated as follows for the hysteresis loop shown in FIG. Stiffness: K = F ₀ / ΔX Equivalent damping constant: Heq = W / (π · ΔABC) Here, F ₀ is the load at the time of maximum displacement, ΔX is the amplitude, W is the area in the loop, and ΔABC is the circumscribed loop. Rectangle A
The value of half the area of BCD is shown.

[0017]

[Table 1]

(Consideration of Table 1) In general, Example 1
Comparative Examples 1 to 4 are rubber compositions for seismic isolation laminated rubber having a compounding composition falling within the scope of the present invention, and Comparative Example 1 is a rubber composition for seismic isolation laminated rubber using the entire amount of natural rubber. Is a rubber composition for a seismic isolation laminated rubber having a composition outside the scope of the present invention. Viewed individually, Example 1 is a blend of 80 parts by weight of natural rubber and 20 parts by weight of ethylene propylene rubber, Example 2 is a blend of 60 parts by weight of natural rubber and 40 parts by weight of ethylene propylene rubber, Example 3 is a blend of 90 parts by weight of natural rubber and 10 parts by weight of ethylene propylene rubber, and Example 4 is a blend of 50 parts by weight of natural rubber and 50 parts by weight of ethylene propylene rubber. It was found that the damping property was improved without impairing the creep characteristics and the tensile characteristics. On the other hand, Comparative Example 2 is a blend of the natural rubber of the present invention and ethylene propylene rubber.
Since it was less than R (40 parts by weight), it was found that the tensile properties were reduced. Comparative Examples 3 to 5 are blends of natural rubber with butadiene rubber (BR), butyl rubber (IIR) and styrene butadiene rubber (SBR), respectively.
In these cases, it was found that creep properties and tensile properties were impaired.

[0019]

According to the present invention, by blending natural rubber and ethylene propylene rubber, rubber for seismic isolation laminated rubber having good damping properties without impairing other physical properties such as creep properties and tensile properties. A composition can be obtained. Further, since a general-purpose ethylene propylene rubber is blended, the material cost can be kept low, and a rubber composition for a seismic isolation laminated rubber which can be manufactured at low cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a laminated rubber produced for evaluating an equivalent damping constant.

FIG. 2 is a characteristic diagram showing a horizontal hysteresis characteristic of a laminated rubber.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16F 15/08 F16F 15/08 B (72) Inventor Satoshi Yamauchi 1-840 Mitsuhashi, Omiya-shi, Saitama Fujikura GOM Kogyo Co., Ltd. 72) Inventor Kazuo Kaneda 1-840 Mitsuhashi, Omiya City, Saitama Prefecture Inside the Omiya Plant of Fujikura Rubber Industries, Ltd.

Claims (1)

[Claims] 1. A rubber composition for seismic isolation laminated rubber, characterized in that natural rubber 50 to 90 PHR is blended with ethylene propylene rubber 10 to 50 PHR.