Ciba-geigy Corporation

Gerhard Umsonst

Max Jost

Gunther Zwahlen

Hans P Kolliker

Andreas Laely

The invention relates to a process for coloring linear polyesters in the melt. The process comprises the use of 1-hydroxy-4-phenylaminoanthraquinones of the formula ##STR1## wherein one X is a hydrogen atom and the other is an alkylsulfonyloxy or chloroalkylsulfoxy group and Y is a hydrogen or halogen atom or an alkyl group. The violet shades obtained are distinguished by excellent color strength and purity and also by good fastness properties.

Process for coloring linear polyesters in the melt

A process for the mass coloration or whitening of linear polyesters, wherein the polyester to be colored is mixed, in the solid or fused state, with a preparation consisting substantially of a colorant or fluorescent brightener which is soluble or insoluble in the polyester, and of a polystyrene with a softening point above 100.degree. C, and the resultant mixture, provided it is not already in the form of a melt, is converted into the molten state and formed into shaped articles. Evenly and deeply colored polyesters are obtained.

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Frenkendorf, Switzerland

Gerhard Umsonst