What is the general workflow of the printing and dyeing factory?

Continuous pad dyeing is generally divided into four main workshops: scouring and bleaching, dyeing, printing and assembly.

First, the basic equipment:

Scouring and bleaching equipment (pretreatment): singeing machine (gas singeing machine and copper singeing machine), scouring machine (open width and rope shape), oxygen bleaching machine, chlorine bleaching machine and mercerizing machine.

Dyeing equipment: hot melt dyeing machine, jig dyeing machine, infrared primer, color developing soaping machine.

Printing equipment: flat screen printing, rotary screen printing, roller printing, transfer printing and digital printing.

Complete set of equipment: setting machine, tenter, grinder, calender, pre-shrinking machine and cutting machine.

Second, the process flow:

1. Inspection of original cotton fabric-reverse printing-sewing-singeing-(desizing)-scouring-bleaching-mercerizing-drying-dyeing-tentering-finishing-tailoring-packaging

2. Original fabric inspection of polyester-cotton blended fabric-reverse printing-sewing-singeing-(desizing)-scouring-bleaching-mercerizing-drying-pre-setting-dyeing (disperse/reactive dyes, disperse vat dyes, etc.). )-post-setting-sorting-code cutting-packaging.

Third, the process conditions:

Singeing: The purpose of singeing is to burn the fluff on the cloth surface, make the cloth surface smooth and beautiful, and prevent uneven dyeing and printing defects caused by fluff during printing and dyeing. Fabric singeing means that the fabric quickly passes through a high-temperature flame or rubs a hot metal surface on the open width. At this time, the fluff on the surface of the fabric quickly heats up and burns, while the fabric body is relatively dense and the temperature rises slowly. Before it reaches the ignition point, it leaves the flame or hot metal surface, so as to burn the fluff without operating the fabric.

Desizing: In order to weave smoothly, textile mills usually size warp yarns to improve strength and wear resistance. The size on cotton fabric can be removed by alkali desizing, enzyme desizing, acid desizing and oxidant desizing.

Scouring: After desizing of cotton fabric, most of the size and some natural impurities have been removed, but a small amount of size and most natural impurities remain on the fabric. Scouring refers to the chemical degradation, emulsification, expansion and other reactions between scouring AIDS such as caustic soda and pectin, waxy substances, nitrogen-containing substances and cottonseed hulls. And impurities are removed from the fabric after washing.

Bleaching: After scouring, the appearance of cotton fabric is not white enough because there are natural pigments on the fiber, which will affect the brightness of color when used for dyeing or printing. The purpose of bleaching is to remove the pigment and give the fabric the necessary and stable whiteness without obvious damage to the fiber itself. The common bleaching methods of cotton fabric are sodium nitrite method, hydrogen peroxide method and sodium chlorite method.

Mercerizing treatment: Mercerizing treatment refers to the process of treating cotton fabric with concentrated caustic soda solution at room temperature or low temperature under tension in both warp and weft directions to improve fabric properties. After mercerizing, the natural twist in the longitudinal direction of the mercerized cotton fabric disappears due to the bulkiness of the fiber, the cross section is oval, and the reverse direction of light is more regular, thus improving the luster.

Dyeing: Dyeing is the process of combining dyes with fibers physically or chemically, or generating pigments on fibers by chemical methods, so that the whole textile has a certain color. Dyeing is carried out under certain conditions, such as temperature, time, PH value and necessary dyeing auxiliaries. Dyed products should have uniform color and good color fastness.

Finishing: Cotton fabric finishing includes mechanical and chemical aspects. The former includes tentering, calendering, electro-optic, embossing and mechanical pre-shrinking finishing. The latter includes soft finishing, stiff finishing, whitening finishing and shrink-proof finishing.