Thermographic material giving stable blue-black image - useful with optical character reader contg. chromogenic fluoran deriv. and aza:phthalide deriv. with di:phenyl sulphone deriv. as developer

摘要

Thermographic material has a base coated with a heat-sensitive layer contg. a colourless or pale-coloured basic chromogenic material, comprising black-developing fluoran deriv(s).. (I) and azaphthalide deriv(s). of formula (II) in an amt. of 3-50 (wt.)% w.r.t. (I), and diphenyl sulphone deriv(s). of formula (III) as colour developer: where A and B is N or one of these is C; R1-R4 is H, alkyl, unsatd. alkyl, cycloalkyl, aryl, aralkyl or tetrahydrofuryl and the ar(alk)yl gps. may have halogen, alkyl or alkoxy substit(s).; or NR1R2 or NR3R4 is a ring; X and Y is halogen, alkyl, alkoxy or acyloxy or one of these is H; R5,R6 is 1-4C alkyl, 2-4C alkenyl, 1-4C alkoxy, benzyloxy or halogen; m, p and q is 0, 1 or 2; and n is 1, 2 or 3. (II) is pref. 3,3-bis(4-diethylamino-2- (m)ethoxyphenyl)-4-, 3-(4-dimethylaminophenyl)- 3-(4-diethylamino-2 -methylphenyl)-4-, 3,3-bis(4-dibutylamino-2- methoxyphenyl)-4-, 3-(4-diethylaminophenyl) -3-(4-(dimethylamino-2- chlorophenyl-7-, 3,3-bis(4-N-ethyl- p-toluidino-2-methoxyphenyl)-4-, 3-(4-dibenzylaminophenyl) -3-(4-diethylamino-2- ethoxyphenyl)-4- or 3-(4-dimethylaminophenyl) -3-(4-diethylamino-2- hexyloxyphenyl)-4-azaphthalide. (III) is 2,4'-dihydroxy- or 4-hydroxy-4'- isopropoxy-diphenyl sulphone. USE/ADVANTAGE - The material gives blue-black images which can be read by optical character readers operating in the 600-700nm wavelength range and can be used for facsimiles and various computers and in other fields. The material gives a black image on a white background, with a contrast of 0.8 or more at 600-700nm, and the image density is hardly reduced after prolonged storage at high temp. and high humidity.