Polymerizable resin for forming clear, hard plastics
US5470892A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1992 |
| Grant date | Nov 28, 1995 |
| Priority date | — |
| Expiry date | May 1, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B1/041
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A photopolymerizable resin is formed from between about 50% to 90% by weight of a polymerizable base component, between about 1% and 20% by weight of a cross-linker, between about 0.5% and 6% by weight of a photoinitiator, and between about 0.5% and 20% by weight of a viscosity control agent. Preferably the resin has a viscosity above 25 and below 130 centistokes at 68.degree. F. In a preferred embodiment, the resin includes between about 0.5% and 3.0% by weight of fumed silica or fine mesh silica as a viscosity control agent, and is cured under the combined influence of heat and actinic radiation to form a clear, hard, plastic optic having a refractive index of greater than or equal to 1.50 and a scratch resistance greater than or equal to 1.0 in a Bayer abrader and hazemeter. A method and apparatus for forming improved ophthalmic lenses is also included.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.