Stabilization of photochromic compounds, and the use of stabilized photochromic compounds
US4503177A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1982 |
| Grant date | Mar 5, 1985 |
| Priority date | — |
| Expiry date | Jul 6, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/73
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The stabilization of selected photochromic compounds, selected from certain fulgides and fulgimides, is made possible by associating with such compounds a clay mineral having an expanding crystal lattice, which can stabilize a selected photochromic compound in a higher-energy colored form. The stabilized photochromic compound may be one included in a coating composition, such as a paper coating composition, or may constitute or be incorporated in a filler for a papermaking furnish or for a plastics material. The stabilizer serves to maintain the photochromic compound in its higher-energy colored state or one of its higher-energy colored states, thereby tending to prevent deterioration of color as the photochromic compound converts to an uncolored or weakly colored lower-energy state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.