Preparation of stable anionic dyestuff solutions: pressure permeation of crude dye in solution of lithium or ammonium salt

摘要

Stable aqueous solutions of anionic dyestuffs, preferably reactive dyestuffs, are obtained at very low costs by pressure permeation, if the feed solution for the pressure permeation is prepared by stirring the optionally dried presscake or the suspension of the crude dyestuff in an electrolyte solution.