Preparation of a photochromic ink
US8287776B2 · kind B2 · utility
0Cited by
5References
6Claims
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Key dates
| Filing date | Dec 23, 2009 |
| Grant date | Oct 16, 2012 |
| Priority date | — |
| Expiry date | Dec 23, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T436/141111
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The present invention relates to a photochromic ink, the process for its preparation which is based on a spiropyran powder obtainable by melting, cooling and crushing, and to a new form of a spiropyran obtainable thereby. Said process to prepare a photochromic ink comprises the steps of a) heating and melting the spiropyran at a temperature below 250 C, b) cooling the melt to obtain a solidified spiropyran, c) crushing the solidified spiropyran to obtain a powder, d) optionally adding the powder to a binder providing the basis for the photochromic ink.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.