| 摘要 |
PURPOSE:To prepare a composition having remarkably improved oil resistance under exposure at high temperature for a long period, especially resistance to gear oil containing large amount of an extreme pressure additive, by compounding zinc carbonate or zinc oxide and if necessary a compound such as thiazole, etc. to an organosiloxane. CONSTITUTION:The objective composition can be prepared by compounding (A) 100pts.wt. of a dihydroxydiorganopolysiloxane of formula (R<1> and R<2> are univalent hydrocarbon group; n is integer of >=5) with (B) 2-30pts.wt. of an organopolysiloxane composed of (i) an organosiloxane unit of formula R<3>3SiO1/2 and (ii) SiO2 unit at a ratio of (0.5-1):1, (C) 0.5-30pts.wt. of an organosilane or siloxane containing three or more hydrolyzable groups bonded to Si in one molecule, (D) 2-200pts.wt. of zinc carbonate and/or zinc oxide, and (E) 0- 20pts.wt. of a compound selected from thiazole, thiuram and dithiocarbamic acid salt. |
