CHROMOGENIC MARKING MATERIAL

摘要

1338617 Fluoran compounds NATIONAL CASH REGISTER CO 1 Nov 1971 [16 Nov 1970] 50665/71 Heading C4P [Also in Division D2] The invention comprises substantially colourless chromogenic marking material which comprises two chromogenic compounds wherein the first of the compounds is of formula where R is H, NO 2 or amino; each R 1 is H, CH 3 or C 2 H 5 ; R 2 is or -CH 2 -R 3 where R 3 is H, phenyl, acetyl, benzoyl, -OCH 3 , -CH = CH 2 , ethoxycarbonyl, N,N - dimethylamido or CH 3 , the groups R both being H when R 2 is -CH 2 -R 3 ; and the second compound is selected from 3,3-bis- (1 - ethyl - 2 - methylindol - 3 - yl) - phthalide, 31 - diethylamino - 61,71 - methylenedioxy fluoran, and fluorans of formulµ where R 4 is H, CH 3 , C 2 H 5 , phenyl, or methoxycarbonyl; each R 5 is H, Cl, CH 3 , C 2 H 5 or SCH 3 ; and ##R 6 represents a 71,81-benzo group or a 71(N)81-pyridino group. The compounds are converted into a coloured form when contacted with an acidic coreactant material, e.g. attapulgite clay or a phenolic polymer.