| abstract |
A thermally sensitive recording medium which comprises, on a substrate, a thermally sensitive colour developing layer which comprises a colourless or pale coloured basic leuco dye and an organic colour developer, wherein the thermal colour developing layer includesn (a) 0.01-0.9 parts by weight, based on 1 part by weight of colour developer, of one or more aminobenzenesulfonamide derivatives of formula (I)n wherein X is oxygen or sulphur, R is a group selected from phenyl, naphthyl, aralkyl, C 1 -C 6 alkyl, C 3 -C 6 cycloalkyl and C 2 -C 6 alkenyl, which group is unsubstituted or substituted, Z is C 1 -C 6 alkyl or an electron attracting group, n is 0 or an integer from 1 to 4 and p is an integer from 1 to 5, provided that n+p≤5; and (b) 0.01-2 parts by weight, based on 1 part by weight of colour developer, of at least one methylolated fatty acid amide of formula (II) R 1 -CONHCH 2 OH wherein R 1 is C 11 -C 21 alkyl. |