Impregnation of plastic substrates with photochromic additives
US5789015A · kind A · utility
80Cited by
47References
20Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1996 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Jun 26, 2016 |
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.