a new method of dyeing textile materials with vat dyestuffs using borohydride as reducing agents such as

摘要

the present invention relates to a new process for dyeing textile materials with vat dyestuffs, in particular by the indigo.the initial dye vat dyestuffs are insoluble in water, and the various methods of dyeing by the dye is usually in four stages: the first stage is the solubilization of the dye in the reduced and caustifiant. this step is carried out by the action of an alkali reduction.the second step is the actual dyeing textile material with a soluble form of the dye. the third step is to fix the dye to the fibre into the oxydee form. the last step is the soap (used for all except the indigo vat dyestuffs.the purpose of this step is to increase the robustness of the dye, and give the final grade on the textile industry. the method that we propose a reduction step is completely different, the classical reduction using sodium hydrosulphite as reduction agent. in fact the reduction agent which is used in this method is a borohydride in the presence of a catalyst.this step can be carried out in the absence of sodium. this new method provides several advantages over conventional methods. these advantages include: 1 - verification easier dyeing parameters. 2, the possibility of phasing out the use of soda ash. 3 - the preservation of the quality of the textile material.4 water discharges caused by this process are free of sulfites and sulfates, and have less pollution than those generated by the conventional methods.