Liquid organopolysiloxane resins, a process for their preparation, low viscosity polydiorganosiloxane compositions containing liquid organopolysiloxane resins and their use

US5932668A · kind A · utility

Assignee

• GE Bayer Silicones GmbH & Co. KG · DE

Inventors

• Robert Friebe · Leverkusen, DE
• Hubertus Eversheim · Wermelskirchen, DE

Key dates

• Filing date: Aug 21, 1996
• Grant date: Aug 3, 1999
• Expiry date: Aug 21, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L2924/0002
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Novel liquid organopolysiloxane resins of the average composition R.sup.1 Si(CH.sub.3).sub.2 O.sub.1/2 !.sub.a (CH.sub.3).sub.3 SiO.sub.1/2 !.sub.b R.sup.2 O.sub.1/2 !.sub.c R.sup.1 Si(CH.sub.3)O!.sub.d (CH.sub.3).sub.2 SiO!.sub.e SiO.sub.2 !, wherein PA1 R.sup.1 is a C.sub.2 -C.sub.8 -alkenyl group, PA1 R.sup.2 is an optionally substituted, linear or branched C.sub.1 -C.sub.8 -alkyl group or a mixture thereof, PA1 a+b+c+d+e is about 1 to 6, PA1 d+e is about 0 to 3, PA1 the resin has a viscosity of 0.1 to 1000 Pas at 25.degree. C., and PA1 the alkenyl or vinyl content of the resin is in the range of 0.4 to 4 mmol/g, and their preparation by reacting at least one of tetraalkoxysilane and its partial hydrolyzate with at least one organosiloxane and a strong acid as catalyst in the presence of water and optionally an organic solvent at a temperature of about >40.degree. C. They are formulated into novel low viscosity polydiorganosiloxane compositions.