Organic photochromic pigment particulates
US4931220A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 24, 1987 |
| Grant date | Jun 5, 1990 |
| Priority date | — |
| Expiry date | Nov 24, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F2/44
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Described is photochromic particulate material comprising a photochromic substance within a matrix of a polymerizate of a polyfunctional acrylate monomer. The photochromic particulate material may be produced by adding an organic photochromic substance to a polymerizable composition including a polyfunctional acrylate monomer and polymerizing the resultant admixture, e.g., by emulsion polymerization. In the case of emulsion or suspension polymerization, finely divided particulate organic photochromic materials are separated from the polymerization medium in the form of spheroidal thermoset photochromic particles of fairly uniform size. If desired, the particles recovered from the polymerization medium may be further ground in conventional attrition mills to further reduce the size of the particulate product. In the case of bulk polymerization, the polymerizate may be formed as a continuously cast sheet, which is then pulverized to a particulate material of pigmentary size.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.