Concentrated aminoanthraquinone blue colorants

摘要

To produce a concentrated solution of aminoanthraquinone dyes in aromatic solvent, quinizarin or a leuco derivative thereof is reacted with a mixture of at least three aliphatic amines in a solvent which is a glycol or a glycol ether. The glycol or glycol ether solvent is present in an amount of 50 wt % or less relative to the quinizarin or leuco derivative plus amines. After the reaction, water and excess amine are stripped and aromatic solvent is added to adjust the dye concentration to the desired concentration above 40 wt % dye./!