Reactive dye salt-free pad dyeing method

Abstract

The invention relates to a reactive dye salt-free pad dyeing method. The method comprises the following steps: (1) mercerizing cotton fabrics, padding caustic soda, then expanding the fabrics, spraying diluted alkali and sucking; then washing with water 2-3 times; and then directly soaking the fabrics in the aqueous solution of caustic soda to carry out alkali wash 2-4 times, drying and cropping for later dyeing so as to obtain the mercerized fabrics with alkali; and (2) dyeing the mercerized fabrics with alkali, wherein dye padding is in an alternately soaking and rolling mode and the machine speed is 20-80m / min; and then pre-drying with infrared for 0-1min, then drying t with hot air and finally washing with cold and hot water and drying. The method has the following beneficial effects: the method is simple to operate and the cost is lowered; and salt-free dyeing is realized under the condition that the performances and color fastness of the dyed fabrics are ensured, the dyeing rate is improved, the washing frequency and water consumption in the mercerizing process are reduced, steam and energy are saved and the method has good economic and social benefits.

Description

technical field [0001] The invention belongs to the field of reactive dye printing and dyeing, in particular to a salt-free pad dyeing method for reactive dyes. Background technique [0002] In the existing reactive dye steaming dyeing technology, it is necessary to add about 200g / L neutral inorganic salt (NaCl or NaCl) during dyeing. 2 SO 4 etc.) to promote dyeing, the amount of salt used is very large, and the discharged dyeing wastewater contains high salinity, and the wastewater with high salt content increases the difficulty of sewage treatment. Although great progress has been made in the treatment of organic compounds in printing and dyeing wastewater, the inorganic salts in wastewater cannot be treated by simple physicochemical and biochemical methods. Direct discharge changes the water quality of rivers and lakes and destroys the ecological environment. [0003] At present, there are still some difficulties in trying to solve this problem, such as: the development...

AI Technical Summary

Problems solved by technology

Although great progress has been made in the treatment of organic compounds in printing and dyeing wastewater, the inorganic salts in wastewater cannot be treated by simple physicochemical and biochemical methods. Direct discharge changes the water quality of rivers and lakes and destroys the ecological environment.

[0003] At present, there are still some difficulties in trying to solve this problem, such as: the development of high directness and new cationic reactive dyes, there is still a certain gap in its color fixation rate or color fastness, especially the positive charge in cationic dyes will The light fastness is adversely affected, and the price is much higher than that of ordinary dyes, and the types are limited; while the cationic modification of cellulose fibers usually affects the shade of the fabric, and the light fastness is also reduced; and the dyes with high directness are not Suitable for continuous pad dyeing

Although the development of new green additives or the selection of salts with high salt effect can reduce environmental pollution, but to achieve the same color depth, it is necessary to increase the amount of organic salts, and organic salts are much more expensive than inorganic salts, which increases the cost of dyeing. Although the amount of salt can be reduced, the pollution is greater than that of inorganic salts

For the above reasons, none of them can be promoted in the factory

[0004] On the other hand, the frequent alternation of rolling, steaming and drying in the dyeing factory causes serious energy consumption and high cost. Moreover, secondary fabrics are continuously produced during the increasing process, forming a vicious circle.