Method for preparing polythiol composition
US11578038B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 2020 |
| Grant date | Feb 14, 2023 |
| Priority date | — |
| Expiry date | Dec 10, 2040 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B1/041
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The embodiments relate to a process for preparing a polythiol composition, which comprises reacting a halogen compound or an alcohol compound with thiourea to prepare a thiouronium salt solution; and adding a basic solution to the thiouronium salt solution to hydrolyze it. The hydrolysis reaction is terminated when the area of peak A in the graph measured by gel permeation chromatography of the reactant in the hydrolysis step under certain conditions is 0.5% to 8% based on the total peak area. A tetrafunctional polythiol composition having high purity can be obtained. Thus, an optical lens having excellent color, transparency, and refractive index can be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.