Impregnation of plastic substrates with photochromic additives
US5851585A · kind A · utility
25Cited by
47References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1997 |
| Grant date | Dec 22, 1998 |
| Priority date | — |
| Expiry date | Nov 14, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J7/048
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The present invention relates to new methods of impregnating plastic substrates with photochromic additives. By impregnating the plastic substrate in multiple impregnation steps under varying conditions, the concentration profile of two or more photochromic additive within the plastic substrate can be independently controlled. Methods are also provided for the distribution of a photochromic additive in a high boiling solvent and for increasing the glass transition temperature of a partially cured polymeric resin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.