Dyeing and finishing process of pure cotton fabric

2、 Dyeing and finishing process of pure cotton fabric
The selection of dyeing and finishing process of pure cotton fabrics can be divided into scouring and bleaching, dyeing, printing, finishing, etc. according to the variety, specification and finished product requirements of the fabrics.
1. Scouring and bleaching natural fibers contain impurities. In the process of textile processing, various sizes, oiling agents and contaminated dirt are added. The existence of these impurities not only hinders the smooth process of dyeing and finishing, but also affects the wearability of the fabric. The purpose of scouring and bleaching is to apply chemical and physical mechanical actions to remove impurities from the fabric, make the fabric white, soft, and have good permeability to meet the wearing requirements, and provide qualified semi-finished products for dyeing, printing and finishing.
The main processes of scouring and bleaching of pure cotton fabrics include: raw fabric preparation, singeing, desizing, scouring, bleaching and mercerizing.
1) Raw cloth preparation: raw cloth preparation includes raw cloth inspection, cloth turning (batch, box, printing) and sewing head. The purpose of raw cloth inspection is to check the quality of grey cloth and solve problems found in time. The inspection contents include physical indicators and appearance defects. The former includes the length, amplitude, weight, density and strength of warp and weft yarn of the original cloth, while the latter includes spinning defects, weaving defects, various stains and damages. Usually about 10% of the total amount is sampled. After the inspection of the raw cloth, the raw cloth must be divided into batches and boxes, and printed on the cloth head, indicating the variety, processing technology, batch number, box number, release date and the code of the person who turns the cloth, so as to facilitate management. In order to ensure continuous batch processing, the original cloth must be sewn.
2) Singing: The purpose of singeing is to burn the down on the cloth surface, make the cloth surface smooth and beautiful, and prevent uneven dyeing and printing defects due to the presence of down during dyeing and printing. Fabric singeing is to quickly pass the fabric through the high-temperature flame or rub the red hot metal surface in an open width. At this time, the fuzz on the cloth surface will quickly rise and burn, while the cloth body is relatively tight and the temperature rises slowly. When it does not rise to the ignition point, it will leave the flame or red hot metal surface, so as to achieve the purpose of burning the fuzz without operating the fabric.