Ciba-geigy Corporation

Werner Saar

Paul Lienhard

Albert Riegler

Volkhard Wiese

Process for mass-coloring nylon in dark brown, dark violet and black shades, which comprises using as dye either mixtures of the 1:2 chromium complex of a monoazo dye of the formula I ##STR1## and the 1:2 chromium complex of a monoazo dye of the formula II ##STR2## or a mixed 1:2 chromium complex of a monoazo dye each of the formula I and the formula II in which R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are as defined in claim 1.

Process for mass-coloring nylon with 1:2 chromium complex azo dye

Preparations which contain 10 to 70% by weight of a pigment or a polymer-soluble colorant and 90 to 30% by weight of a carrier mixture which is composed of 51 to 95% by weight of a metal salt of an aliphatic carboxylic acid containing at least 12 carbon atoms, said metal selected from the group consisting of calcium, barium, zinc, aluminum, and magnesium, and of 49 to 5% by weight of an elastomeric or thermoplastic polymer are useful for coloring molten thermoplastic polymers in level shades.

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Riehen, Switzerland

Werner Saar