| 摘要 |
PROBLEM TO BE SOLVED: To produce a foamed rubber member having an optimal foamed state by coating each surface of a member made from an unvulcanized rubber containing a blowing agent with a thin film of an unvulcanized rubber having a vulcanization rate lower than that of the above unvulcanized rubber and a specified Mooney scorching time. SOLUTION: A mixture containing a stock rubber such as an ethylene/ propylene/diene copolymer rubber (EPDM), a blowing agent (e.g. p- toluenesulfonyl hydrazide), carbon black, a vulcanizing agent, a vulcanization accelerator, etc., is kneaded and extruded to form a sheet having a Mooney viscosity [ML(1+4) , 100 deg.C] of 25-45. Next, a mixture containing a stock rubber (e.g. EPDM/nitrile rubber), a blowing agnet, carbon black, a vulcanization accelerator, etc., is kneaded and rolled to form a 0.1-0.5mm thick thin film of an unvulcanized rubber having a Mooney scorching time ts of 2-15min and a Mooney viscosity of 15-60. The thin film is stuck to each surface of the sheet, and the assemblage is vulcanized by heating to obtain a foamed rubber member having a specific gravity of about 0.40-0.55 and a cell diameter of about 0.01-0.1mm. |
