Nylon/cotton fabrics are usually dyed by two-bath over-dyeing, that is, dyeing nylon with neutral, acid or disperse dyes, and then dyeing cotton with medium-temperature reactive dyes. The two-bath over-dyeing method is used for dyeing. The advantage is that the color (shade, shade) of nylon and cotton fibers can compensate each other during the over-dyeing process, and the color of the cloth surface is easier to adjust and control; the disadvantage is that the process takes a long time, the processing output is low, and energy High consumption, high sewage discharge, and poor economic benefits.
Nylon/cotton or cotton/nylon fabrics can be dyed light colors with one-bath method of disperse/thermosetting reactive dyes, neutral/thermosetting reactive dyes can be used for one-bath dyeing, and neutral/high temperature type can be used Reactive dyes dye dark colors in one bath. Practice has proved that the dyeing effect of the one-bath method is equivalent to that of the traditional two-bath over-dyeing method, and has outstanding advantages of "energy saving, emission reduction, and efficiency increase".
Polyamide/cotton fabrics were once dyed with neutral dyes and medium temperature reactive dyes in one bath and two steps. That is, under the condition of adding electrolyte, dyeing in a neutral bath at 85°C, then cooling to 60°C and fixing the color with alkali, and then washing and washing.
But this dyeing method has three disadvantages:
One is that when the neutral dye is dyed at 85℃, the dye uptake to nylon is about 10%-15% lower than that at 95～98℃, which cannot reach the highest exhaustion rate;
Second, the medium-temperature reactive dyes absorb color at higher temperatures, which stains the nylon heavily, and it is difficult to control the shade of the nylon component;
The third is that the reproducibility of the color (shade, depth) of the dyeing process is poor, and the tank difference is prominent, so the dyeing method has been eliminated. After research, nylon/cotton fabrics can be dyed light colors in one bath with disperse dyes and thermosetting reactive dyes, neutral dyes and thermosetting reactive dyes in one bath, neutral dyes and high temperature reactive dyes. Dye dark colors in one bath and two steps.