Polymerization of cyclosiloxanes in the presence of fillers
US6001928A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1998 |
| Grant date | Dec 14, 1999 |
| Priority date | — |
| Expiry date | Feb 20, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08K3/36
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for which making silicone-filler mixtures which comprises effecting the ring-opening polymerisation of a cyclosiloxane with a phosphazene base in the presence of a filler and of water, preferably from 0.5 mil to 10 mols of water per mol of phosphazene base. The filler is preferably selected from silica, alumina, titanium dioxide, carbon black and calcium carbonate, present in an amount of from 1 to 200 parts by weight per 100 parts by weight of cyclosiloxane. An agent or conditions which inhibit catalyst activity may initially be present (e.g. carbon dioxide or excess water), and polymerisation may be initiated by reducing the effect of the inhibiting agent or conditions (e.g. by heating). Silicon-elastomers produced by curing such silicone polymer-filler mixtures are also claimed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.