| 摘要 |
PROBLEM TO BE SOLVED: To bear the large deformation by forming a base isolation rubber device by alternatively laminating a plurality of hard plates and rubber plates, forming the rubber plate by vulcanizing a rubber composition containing prescribed respective quantities of rubber components and carbon black, and by mixing prescribed respective quantities of natural rubber and isoprene rubber in the rubber components. SOLUTION: This device is formed by alternatively laminating rubber sheets 1 and steel plates 2, and its top and the bottom are sandwiched between a fitting flange 3 so as to provide a central hole. The sheet 1 is provided by vulcanizing a rubber composition containing rubber components and carbon black 10-90 pts.wt. to the rubber components 100 pts.wt. and the rubber components are formed by mixing isoprene rubber 20-80 pts.wt. of cis ratio 80-95% to natural rubber 80-20 pts.wt. When the mixing rate of the natural rubber exceeds this, the linearity improvement by adding of trans components is disappeared and when it is less than this, the decrease in the fracture strength and extension become remarkable. This constitution can reduce the compressive permanent strain, improves linearity of a stress-strain curve, and hardly reduce the performance in a large deformation. |
