| 摘要 |
PURPOSE:To improve the mold release properties and the durability necessary for a material for a layer to prevent toner offset in an electronic copying machine, other covering materials, etc., by incorporating a specified quantity of a dry-process silica into a blended rubber obtained by mixing two specified silicone rubbers. CONSTITUTION:At least one vinyl-group-containing silicone rubber (A) which has a molecular weight of 500,000-1,500,000 and contains 0.01-0.1mol% vinyl groups, and at least one vinyl-group-containing silicone rubber (B) which has a molecular weight of 100,000-1,000,000 and contains 0.5-30mol% vinyl groups are mixed in the ratio of A to B of 60-97:40-3(pts.wt.) and of 1mol% or less, forming a blended rubber. A dry-process silica (preferably a particle diameter of 3-30mum and a specific surface of 70-380m<2>/g) in an amount within limits not to bring the specific gravity of the composition to 1.2 or higher is incorporated into this blended rubber to give a silicone rubber composition. A conventional vulcanizing agent is added to this composition, which is molded and vulcanized to produce a silicone rubber molded article. |
