Process for preparing a sulfur-containing urethane-based plastic lens and the lens prepared thereby
US5837797A · kind A · utility
20Cited by
2References
17Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1996 |
| Grant date | Nov 17, 1998 |
| Priority date | — |
| Expiry date | Nov 25, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B1/041
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A novel polythiol having four or more functional groups, a process for producing the polythiol comprising reacting thiourea with a specific compound, a sulfur-containing urethane-based resin prepared from the polythiol and a lens made of the resin. The resin has a high refractive index, and low dispersion of refractive index, is lightweight, colorless and transparent, has no optical distortion, and has excellent characteristics in weatherability, dye-affinity, heat resistance, impact resistance and machinability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.