PROCESS FOR CONVERTING HARD SOLUBLE SALTS OF ANIONIC DYES AND FLUORESCENT WHITENERS TO READILY SOLUBLE SALTS BY CATIONEXCHANGE

摘要

A process is described for converting sparingly soluble salts of anionic dyes and fluorescent brighteners into more soluble salts by means of cation exchange without intermediate isolation of the free dye acid, which comprises carrying out the cation exchange by using Donnan dialysis. The concentrated dye and brightener solutions obtained in this way are stable and can be directly used for dyeing or printing textile material.