Photochromic dyes
Photochromic dyes are dyes that react to exposure to UV light (sunlight or black light ) with a reversible change in color. The UV light changes the chemical structure of the dyes and thus their absorption behavior ( photochromism ).
The dyes that are used in the manufacture of coating materials and optical materials are available in four or more basic colors that change from white to purple , blue , yellow or red .
Photochromic dyes for printing on textiles are used for coloring unterschiedlichster materials as well as for the production of plastic articles . For some time now, photochromic dyes have also been available as screen printing inks. This means that it is also possible to use these in classic print finishing.
Until summer 2007 only unstable photochromic dyes were known. They changed their chemical structure over time . The longer and more often the colors have been exposed to UV light, the less they will return to their original state. By integrating nano-encapsulation, a research team from Rodenstock GmbH has succeeded in permanently integrating dyes through nano-encapsulation and thereby achieving improved light and weather fastness. In 2010, facade paints on a similar basis in zeolites were presented.
In addition to photochromic colors, there are also thermochromic colors that react to temperature and moisture-sensitive hydrochromic colors .
Individual evidence
- ↑ Edwin Van Onna: Material World .: Innovative materials and coatings for interiors. Springer, 2003, ISBN 3-7643-6745-8 , pp. 145 ( limited preview in Google Book search).
- ↑ Google Patents: Patent EP0686685B1 - Photochromic Dyes , accessed May 18, 2014
- ↑ Thuringian Institute for Textile and Plastics Research e. V .: Final report - extended functionality and higher performance of photochromic textiles using chemiluminescence analysis , February 13, 2013, accessed on May 18, 2014
- ↑ Manuela Frick: Photochromic Textiles - Production and Properties , accessed on May 18, 2014
- ↑ Google Patents: Patent WO2011144354A1 - Process for the production of a coating composition with reversible color change for the UV light absorbing finishing of substrates , accessed on May 18, 2014
- ↑ Google Patents: Patent WO2007068410A2 - Photochromic plastic object , accessed on May 18, 2014
- ↑ Fraunhofer IKTS Annual Report 2010: mitte_10_Annual Report - NANOPARTICULAR ZEOLITHES AS HOST FOR PHOTOCHROME DYES ( Memento of May 18, 2014 in the Internet Archive ), accessed on May 18, 2014