Thermographic cholesteric coating compositions

Abstract

Thermographic cholesteric coating compositions, containing cholesteric microcapsules, and coated plates are provided which give gray-red-green-blue coated temperature-responsive visual displays, over about a 3.degree. or 4.degree. C. range. Formulations are devised to give the displayed range, in about 1.degree. C. intervals from about 28.degree. C. to about 37.degree. C. The microcapsules contain about 55% oleyl cholesteryl carbonate, about 2.0 to about 5.0% cholesteryl propionate and about 4.5 to about 7.2% of cholesteryl chloride. Coatings containing two different microencapsulated formulations, both selected within the above formulation range give thermographic plates showing a temperature-responsive visual display of seven distinct color shades, over about a 4.degree.-7.degree. C. range, without loss of sensitivity and without loss of noticeable color intensity.

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