Mercapto compound, its preparation process, and sulfur-containing urethane resins and lenses using the same
US5352758A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1993 |
| Grant date | Oct 4, 1994 |
| Priority date | — |
| Expiry date | Dec 20, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B1/041
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A mercapto compound represented by the following formula (1): ##STR1## is obtained by reacting, in the presence of a mineral acid, thiourea with a compound represented by the following formula (2): ##STR2## wherein X means a hydroxyl group or a chlorine or bromine atom, and then adding a base to alkalinize the reaction mixture so that the reaction product is hydrolyzed. The mercapto compound represented by the formula (1) can be reacted with at least one cyanate compound selected from the group consisting of polyisocyanate compounds, polyisothiocyanate compounds and isocyanate-group-containing isothiocyanate compounds to form a sulfur- containing urethane resin. A lens made of the resin is colorless and transparent, has high refractive index and low dispersion characteristics, and is excellent especially in heat resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.