Optically clear filled silicone elastomers
US3996187A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 29, 1975 |
| Grant date | Dec 7, 1976 |
| Priority date | — |
| Expiry date | Apr 29, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G77/70
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Reinforced silicone elastomers, having improved tensile strength and particularly tear strength, include at least copolymers of aryl siloxanes and alkyl siloxanes, in a particular ratio of aryl to alkyl substituents, having reflective indices matched to the index of refraction of a silicone filler, forming optically clear material, useful for soft contact lenses. PAC FIELD OF THE INVENTION This invention relates to optically clear, reinforced, inter-polymers of aryl and alkyl siloxanes, forming silicone elastomeric, soft plastic contact lenses. PAC BACKGROUND OF THE INVENTION Many silicone elastomers, when unfilled, generally have excellent optical clarity and are usually water white in color. The tensile strength, and especially the tear strength, of such elastomers is poor, however. By filling the elastomers with fine particulate solids, the silicone gum stock will produce, when vulcanized and cured, an elastomer with much improved strength. Fillers used with the silicone elastomers have been the usual fillers for plastics, but the fillers are limited when optical clarity of the elastomer is an essential. Commonly used dimenthyl siloxane, with a vulcanizing agent, produces a sili…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.