| 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 DEG or 4 DEG C. range. Formulations are devised to give the displayed range, in about 1 DEG C. intervals from about 28 DEG C. to about 37 DEG 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 DEG -7 DEG C. range, without loss of sensitivity and without loss of noticeable color intensity. |