Cotton textile printing and dyeing process:
Matching blank--seam head--singeing--cold rolling car--destroying, scouring and bleaching--mererizing--pre-set tentering--sizing--printing (flat screen or rotary screen printing)--steaming machine- -Soaping machine--Finishing and shaping--Pre-shrinking machine--Calendar--Quality inspection and packaging
First. Singeing
Usually, after the grey fabric enters the printing and dyeing factory, it first needs to go through the processes of inspection, turning the fabric, batching, matching blanks (blanking: the front and back sides of the two grey fabrics are joined together on the same side) and seaming, and then the singeing process is carried out.
Singeing: The process of singeing looks amazing. At the scene, you will see the fabric passing through the high-temperature flame quickly, while the cloth slides quickly on the fierce flame, but it does not burn. The realm of "touching one's body".
This is because the cloth body is relatively tight and the temperature rises slowly. Before reaching the ignition point, it has already left the flame or red hot metal surface, so as to achieve the purpose of burning off the fluff without damaging the fabric.
Reason: The unsinged cloth surface has too much fluff, the length is different, the finish is poor, and it is easy to stain. It is easy to shed hair in the subsequent dyeing and finishing process, resulting in printing and dyeing defects.
Significance:
1. The purpose of singeing is to burn off the fluff on the cloth surface to make the cloth surface smooth and beautiful, and to prevent uneven dyeing and printing defects due to the existence of fluff during dyeing and printing. Improve the gloss of the cloth surface and improve the finish;
2. Improve anti-pilling performance (especially chemical fiber fabric);
3. Improve the style, singeing will make the fabric crisp.
Cold rolling car: a process after singeing, the grey fabric needs to be cooled for more than 20 hours
Second. De-boiling and bleaching
Desizing, scouring and bleaching, that is, desizing, scouring and bleaching.
Desizing: The slurry on the grey cloth should be removed before scouring. This process is called desizing.
In order to increase the abrasion resistance of warp yarns in weaving, the smoothness and antistatic properties of textile fabrics, increase the strength, and improve the weaving properties, sizing processing must be carried out before weaving. The slurry on the grey fabric not only affects the water absorption performance of the fabric, but also affects the quality of dyeing and finishing products, and will increase the consumption of dyeing chemicals. Therefore, the slurry should be removed before scouring. This process is called desizing. It is about to be removed from the fabric.
Scouring: Refining is also called scouring, its purpose is to remove fiber impurities (natural impurities, artificial impurities) and improve fabric processing performance, especially wetting performance.
When cotton fiber grows, it is accompanied by natural impurities (pectin, waxy substance, nitrogenous substance, etc.). After the cotton fabric is desizing, most of the size and some natural impurities have been removed, but a small amount of size and most of the natural impurities still remain on the fabric. The presence of these impurities makes the cloth surface of cotton woven fabrics yellower and poorer in permeability. At the same time, due to the presence of cotton seed hulls, the appearance quality of the cotton cloth is greatly affected.
Therefore, the fabric needs to be scoured for a long time in high-temperature concentrated lye to remove residual impurities
Bleaching: After the cotton fabric is scoured, because there are natural pigments on the fiber, its appearance is not white enough. If it is used for dyeing or printing, it will affect the vividness of the color.
Purpose of bleaching: remove pigments and improve whiteness as the main purpose of bleaching.
Third, mercerizing
Mercerizing: The cotton woven fabric is treated with a concentrated alkali solution, and its surface presents a silky luster. More importantly, it will improve its dimensional stability, that is, the cotton woven fabric is shaped.