摘要 |
The invention relates to a process for the preparation of storage stable compositions of sparingly soluble or water-insoluble colorants, which process comprises mixing an aqueous suspension of at least one sparingly soluble or water-insoluble colorant with at least one surface-active substance, subjecting the mixture to ultrafiltration through an asymmetrical membrane which contains ionic groups and has a pore diameter of 1 to 500 ANGSTROM and a cut-off level in the molecular weight range from 300 to 500, subsequently subjecting the resultant concentrate to wet grinding and, if desired, drying, in particular spray drying the dispersion so obtained. The colorant compositions are particularly suitable for preparing padding liquors, dyebaths and printing pastes for coloring and printing textile materials, especially those made from cellulose and synthetic polyester.
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