Trends of key materials for direct thermal papers

The coating color for the direct thermal paper basically consists of the leuco dye, the cobr developer and the sensitizer. Blacking dyes to be used for thermal papers call for other practicable properties than the tone, such as storage stability, thermal sensitivity and white background. Since no universally accepted theory in choosing proper developer and sensitizer is available, however, selection will have to be conducted on the designer's experience. Such practical considerations as the stability of the recorded image and matching with the particular machine to be used for are important beside the chemical considerations.