Sulfur-containing polyurethane base lens resin
US4780522A · kind A · utility
22Cited by
4References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 4, 1987 |
| Grant date | Oct 25, 1988 |
| Priority date | — |
| Expiry date | Mar 4, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B1/043
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A sulfur-containing polyurethane base lens resin is obtained by reacting one or more isocyanate compounds, which have two or more NCO groups, with one or more OH-containing compounds, which have two or more OH groups, in such proportions that the molar ratio of NCO groups to OH groups ranges from 0.5 to 1.5. At least one of said one or more OH-containing compounds contains one or more sulfur atoms in the molecule thereof. The total content of sulfur atoms in all OH-containing compounds is 20 wt. % or higher.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.