Silyl ester initiators for cyclosiloxane ring opening polymerization
US5696219A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1997 |
| Grant date | Dec 9, 1997 |
| Priority date | — |
| Expiry date | Jan 21, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G77/24
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Method of making polysiloxanes by ring opening polymerization of 1,3,5-trimethyl-1,3,5-tris(3',3',3'-trifluoropropyl) cyclotrisiloxane (F.sub.3) or 1,3,5,7-tetramethyl-1,3,5,7-tetrakis(3',3',3'-trifluoropropyl) cyclotetras iloxane (F.sub.4) in an acid-free system using electrophillic initiators. The reaction mixture is formed under anhydrous conditions and contains (i) either F.sub.3 or F.sub.4, (ii) a Lewis base such as 2,6-di-tert-butylpyridine which serves as an acid scavenger, and optionally (iii) a salt of a strong acid such as tetrabutylammonium trifluoromethane sulfonate. The anhydrous mixture is contacted with a silyl ester of a strong acid such as triflic acid. The anhydrous reaction mixture is agitated at room temperature until a polysiloxane is formed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.