Microemulsions of gel-free polymers
US5661215A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 26, 1995 |
| Grant date | Aug 26, 1997 |
| Priority date | — |
| Expiry date | Jul 26, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G77/06
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Described is a method of preparing microemulsions of organopolysiloxanes, by copolymerizing a cyclic siloxane and a polyfunctional silane, in an aqueous medium containing a nonionic surfactant, an anionic or cationic surfactant, and a catalyst, until the desired increase in molecular weight is obtained. The invention resides in controlling the gel content of the organopolysiloxanes in the microemulsion by control of the concentration of silane and concentration of silanol in the resulting organopolysiloxane, such that a functionality ratio .phi. results in formation of a gel-free polymer molecular weight distribution of finite organopolysiloxane species in the microemulsion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.