A thermally color-developing reversibly thermochromic pigment which shows a uniform color density in the coloring temperature range and also shows an optimal ΔH value within a range of from 3 to 40° C. Thermally color-developing reversibly thermochromic pigments of a three component system having a...http://www.google.com/patents/US7332109?utm_source=gb-gplus-sharePatent US7332109 - Thermally color-developing reversibly thermochromic pigment
