Nields, Lemack & Dingman
Thermal recording material and novel crystal of bisphenol S derivative
 A heat-sensitive recording material in which a heat-sensitive color-developing layer comprising, as the main components, a usually colorless or light-colored color former and a developer capable of developing the color former upon heating on a support, characterized by comprising, as the developer, crystals of 3,3'-diallyl-4,4'-dihydroxy-diphenyl sulfone which have DSC (Te) of at least 149.degree. C. and which are of a crystal form characterized by an X-ray diffraction pattern having peaks at least at diffraction angles (2.theta.) [.degree.] of 7.2 and 22.0, obtained by an X-ray powder diffractometry using Cu--K.alpha. rays. This heat-sensitive recording material is high in sensitivity, little in Discoloration of the ground in heat and moisture and excellent in image durability. 
Nippon Kayaku Kabushiki Kaisha
B C
B41M C07C
inventional inventional
Masaaki Masao Hirofumi
Saito Onishi Iwamoto