| 摘要 |
PROBLEM TO BE SOLVED: To provide an elastic rubber utilized for a washer to be used together with a bolt and a nut in case of joining wood to wood, for example connecting a column and a beam of a wooden framework house, the residual deformation percentage of which is less than 15% after a long-term use under a 50% compression condition, preventing premature deterioration and breakage due to excessive fastening, having excellent weatherability, and preventing deterioration of restoring force due to permanent deformation. SOLUTION: This elastic rubber is a composition containing 0-1.0 pts.wt. of oil sulfur, 1.5-3.0 pts.wt. of vulcanization accelerator, 50-80 pts.wt. of carbon black, 3-8 pts.wt. of age resistor, and other additives blended with 100 pts.wt. of natural rubber, and characterized in that residual deformation after long-term use under a 50% compression condition is 15% or below.
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