Tti indicator with balanced photochemical processes
AssigneeCiba Corporation
InventorsAndre Fuchs, Anne Veronica Carrigan
Life of this patent
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Abstract
The invention relates to a time temperature indicator comprising a) at least one photo-chromic colorant introduced into and/or atop a matrix substrate and charged by exposure to UV light; b) at least a transparent colorless or a transparent colored light absorbing protecting layer adhered to the underlying layer a) which contains the photo-chromic colorant; characterized in that the light absorbing protecting layer comprises 1-50 wt % of an UV light absorber or an UV light absorber mixture and 0.1-10 wt % of an optical brightener wherein the weight ratio of the UV light absorber and optical brightener is 0.1-10.
Claims9
A time temperature indicator comprising
- a) at least one photo-chromic colorant introduced into and/or atop a matrix substrate and charged by exposure to UV light;
- b) at least a transparent colorless or a transparent colored light absorbing protecting layer adhered to the underlying layer a) which contains the photo-chromic colorant;
- characterized in that the light absorbing protecting layer comprises 1-50 wt % of an UV light absorber or an UV light absorber mixture and 0.1-10 wt % of an optical brightener wherein the weight ratio of the UV light absorber and optical brightener is 0.1-10.
(canceled)
Dependencies are inferred from the claim text.