| 摘要 |
1,176,454. Siloxane copolymers. DOW CORNING CORP. 5 July, 1968 [20 July, 1967], No. 32133/68. Heading C3T. A process for preparing a fluoralkyl silicon resin which comprises: (1) mixing with an aqueous system having a pH <7, (a) 30-90 mole per cent of a silane RSiX 3 in which R is a perfluoroalkylethyl radical and each X is an alkoxy or acyloxy radical containing <7 C atoms, (b) 0-40 mol per cent of a silane RR<SP>1</SP>SiX 2 where R and X are as defined above and R<SP>1</SP> is a monovalent hydrocarbon radical or a perfluoroalkylethyl radical, and (c) 0-50 mol per cent of an organosilane YSiX 3 where X has the meaning defined above and Y is a monovalent hydrocarbon radical; (2) neutralizing the acidic pH and separating the co-hydrolysate from the aqueous system; (3) washing the co-hydrolysate and (4) recovering the fluoralkyl silicon resin. In a preferred process (a) has the formula: CF 3 CH 2 CH 2 Si(OCH 3 ) 3 , (b) has the formula: CF 3 CH 2 CH 2 Si(CH 3 )(OCH 3 ) 2 and (c) has the formula: C 6 H 5 Si(OCH 3 ) 3 or CH 3 Si(OCH 3 ) 3 . Claimed per se are siloxane copolymers which comprise: (a) 70-90 mol per cent of units RSiO 3 / 2 , (b) 0-30 mol per cent units RR<SP>1</SP>SiO and (c) 0-30 mol per cent of units ZSiO 3/2 when R, R<SP>1</SP> and Z are as defined above. R<SP>1</SP> is preferably CH 3 and each Z also CH 3 . A preferred copolymer comprises: 75 mol per cent of units: CF 3 CH 2 CH 2 SiO 3/2 , 10 mol per cent of units CF 3 CH 2 CH 2 Si(CH 3 )O, and 15 mol per cent of units CH 3 SiO 3/2 . |
