| 摘要 |
PURPOSE:To provide a rubber compsn. which exhibits excellent physical properties even when the mixing ratio of particulate rubber is extremely high, by a method wherein particulate vulcanized rubber composed of spew rubber is mixed with a polybutadiene-contg. unvulcanized rubber compsn. matrix, and the mixture is vulcanized. CONSTITUTION:At least 1,000pts.wt. vulcanized rubber component (B) having a specific surface area of 50cm<2>/g or smaller and at least 3pts.wt. sulfur (C) are blended with 100pts.wt. unvulcanized rubber component (A) which contains 20- 85wt% polybutadiene as essential component and natural rubber and/or at least one member selected from synthetic cis-1,4-polyisoprene and a styrene-butadiene copolymer mixed therewith. The mixt. is vulcanized. The resulting rubber compsn. is disimilar in physical properties to conventional rubber compsn. formed by mixing particulate or powdered rubber. Even when a large amount of the particulate rubber is mixed, physical properties such as wear resistance, flex resistance and breaking strength of the obove rubber compsn. are not lowered, and thus, the above process is extremely effective as the method of re-using spew rubber. |
