Summary:The dyeing and finishing production process of cotton knitted fabrics includes scouring, bleaching, dyeing, printing, fi...
The dyeing and finishing production process of cotton knitted fabrics includes scouring, bleaching, dyeing, printing, finishing and other processes. It plays an important role in improving the appearance of knitted fabrics, improving performance, improving product quality, and increasing varieties of designs and colors.
1. Scouring and bleaching The main processes of scouring and bleaching of cotton knitted fabrics are: scouring, bleaching, alkali shrinkage, waxing, etc. Among them, the processing principles and agents of scouring and bleaching are the same as those of cotton cloth, and will not be repeated. However, cotton knitted fabrics are connected by loops, and the gaps between the yarns are large, which are easy to deform and cannot withstand large tensions. Therefore, loose processing equipment must be used during processing. The following is a brief introduction to the processes of alkali shrinkage and waxing.
1) Alkali shrinkage: Alkali shrinkage of cotton knitted fabrics is the process of treating cotton knitted fabrics with concentrated alkali in a relaxed state. Cotton fiber expands in concentrated caustic soda, the fabric shrinks, and the fabric density and elasticity increase. For the processing of fabrics such as loose jersey, alkali shrinkage includes three steps, namely padding with lye, stacking shrinkage and washing to remove alkali.
2) Waxing: after scouring and bleaching of cotton knitted fabrics, after the oil and wax substances of cotton fibers are removed, the friction between fibers increases. When sewing, because the fibers are not easy to slip, the needles are easy to break the fibers and cause needle holes in the fabric, which affects the wearing fastness. In order to solve this problem, in addition to strictly controlling the process conditions, softening treatment, that is, waxing, is carried out at the same time. The dehydrated fabric is dipped in paraffin emulsion, and then dehydrated and dried.
2. Dyeing and printing The dyeing and printing of cotton knitted fabrics are basically the same as those of cotton fabrics and will not be repeated here. Loose processing equipment such as rope dyeing machines should be used for dyeing. Prints are hand printed or lithographed.
3. Finishing The finishing of cotton knitted fabrics mainly includes shrink-proof finishing and pile finishing. Cotton knitted fabrics are susceptible to stretching and accumulated deformation during dyeing and finishing. Once washed, the accumulated deformation of the fabric will retract, causing dimensional changes. Anti-shrinkage finishing is the forced retraction of the fabric in the state of damp heat relaxation, so that the size of the fabric is stable. Cotton knitted flannelette needs to be piled up. Fleece finishing is to pull out the fibers in the floating threads of the knitted gray fabric to form and fluff, so as to make the fabric soft. Thin feel with enhanced warmth. Different types of cotton knitted fabrics have different dyeing and finishing processes.