| 摘要 |
PURPOSE:To obtain a silicone rubber compsn. which gives a vulcanizate which is excellent in mechanical strengths and withstands a long-term contact with a mineral-oil-based lubricant by compounding a specific raw organopolysiloxane rubber, a fine silica powder, a specific diorganopolysiloxane oil, and an org. peroxide. CONSTITUTION:This rubber compsn. is prepd. by mixing 100 pts.wt. raw organopolysiloxane rubber having the mean compsn. formula: RaSiO(4-a)/2 [wherein R is a (substd.)monovalent hydrocarbon group; and (a) is 1.8-2.3] and at least two alkenyl groups directly bonded to Si atoms in the molecule with 40-200 pts.wt. fine silica powder and a diorganopolysiloxane oil having a viscosity at 25 deg.C of 1-1,000cP and not having an alkenyl group in the molecule in a wt. ratio of the silica powder to the oil of (1:0.2)-(1:3.5) and then with 0.1-10 pts.wt. org. peroxide. The compsn. gives a vulcanizate which is excellent in mechanical strengths, swells little even when kept always in contact with a mineral-oil-based lubricant, and hence can be used for a long term. |
