Wärmeübertragungsdrucken.

摘要

A thermal transfer printing sheet suitable for the printing of black images in a dye diffusion thermal transfer printing process. The sheet comprises a substrate having a coating comprising a black dye mixture comprising from 5 to 60% of a dye of Formula 1, from 5 to 60% of Formula 2, from 5 to 60% of a dye of Formula 3 and/or from 1 to 60% of a dye of Formula 4. Dyes of Formula (1) are represented as: wherein: X is -H; nitro or -COOR<1> in which R<1> is an optionally substituted hydrocarbyl radical; Y is an optionally substituted C1-10-alkyl; optionally substituted C1-10-alkoxy or halogen; Z is an alkyl radical, and R is an alkyl radical which may be interrupted by one or two -O- or -COO- links. Dyes of Formula 2 are represented as: A-N=N-E Formula 2 wherein: A is the residue of a dizotisable heteroaromatic amine, A-NH2, in which A is selected from imidazolyl, pyrazolyl, thiazolyl, benzothiazolyl, isothiazolyl, benzoisothiazolyl, pyridoisothiazolyl; thienyl and triazolyl; and E is the residue of an aromatic coupling component, E-B, wherein B is a group displaceable by a diazotised aromatic amine and E is optionally substituted aminophenyl, tetrahydroquinolinyl, julolidyl or aminoquinolinyl. Dyes of Formula 3 are represented as: C-N=N-D-N=N-G Formula 3 wherein: C is the residue of a diazotisable phenylamine or naphthylamine, C-NH2, carrying not more than one unsaturated electron-withdrawing group; D is an optionally substituted thiophen-2,5-ylene or thiazol-2,5-ylene group; and G is the residue of an aromatic coupling component G-J wherein J is a group displaceable by a diazotised aromatic amine. Dyes of Formula 4 are represented as: wherein: R<1><2> is C1-6-alkyl, C4-8-cycloalkyl or C2-6-alkenyl; R<1><3> is C1-6-alkyl or C2-6-alkenyl; and R<1><4> is H or C1-6-alkyl or C2-6 -alkenyl.