| 摘要 |
1434528 Organopolysiloxane compositions DOW CORNING Ltd 24 Sept 1973 [26 Sept 1972] 44357/72 Heading C3T A curable organopolysiloxane composition comprises (A) a mixture and/or a reaction product of (i) an hydroxyl-terminated diorganopolysiloxane having a viscosity of at least 100 cS at 25‹ C., the organic substituents being monovalent hydrocarbon or halohydrocarbon radicals and (ii) an organosilicon compound having on the average at least three -ON=X radicals bonded to silicon, wherein X is -CR 2 or CR<SP>1</SP> where R is a monovalent hydrocarbon or halohydrocarbon radical and R<SP>1</SP> is a divalent hydrocarbon or halohydrocarbon radical, all the remaining valencies of the silicon atoms in (ii) being satisfied by hydrogen atoms, hydrocarbon or halohydrocarbon radicals or oxygen atoms of siloxane linkages, and (B) from 0À1 to 5% wt. based on the weight of (A) of an organic peroxide or perester. The organosilicon compound (ii) may be a silane of the formula where a is 0 or 1, or a silcarbane of the formula where R<SP>111</SP> is a divalent hydrocarbon radical, d=1-3, f=0, 1 or 2, a=1-4, m=0, 1-3. Suitable peroxides and peresters are benzoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, t-butylperbenzoate, -peracetate, or -percrotonate. Optional ingredients include fillers such as silicas, CaCO 3 , iron oxide, ZnO, MgO and TiO 2 ; pigments; plasticizers; and catalysts, e.g. tin carboxylates. In the example a curable composition prepared from an OH-terminated polydimethylsiloxane having a viscosity of 13,500 cS, reinforcing fume SiO 2 , OH-terminated phenylmethylsiloxane liquid, CH 3 Si[ON = C(CH 3 ) 2 ] 3 , dibutyltin octoate, and 2,4-dichlorobenzoyl peroxide in silicone oil, is cast into a sheet and cured by exposure to the atmosphere at 22‹ C. Uses.-Electrical insulation; sealants, adhesives. |
