Ciba-geigy Corporation

Andreas Laely

Gunther Zwahlen

Lothar Buxbaum

Gerhard Umsonst

The invention provides a method for the production of a pigment preparation for coloring linear polyesters in the melt, which comprises forming a concentrate from 20 to 80 parts of pigment and 80 to 20 parts of a polyester which melts between 60.degree. and 160.degree. C., by kneading in the presence of a salt and a solvent or by a flush process, mixing said concentrate with a fibre forming linear polyester, melting the mixture and processing it to granules. The invention also provides the pigment preparation obtained by the process and the linear polyesters colored therewith.

Method for the production of a pigment preparation for coloring linear

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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Allschwil, Switzerland

Andreas Laely