The whole cotton fabric dyeing process includes pretreatment, dyeing, finishing and finished product inspection

（1） Pretreatment part:

When turning seams, pay attention to the binding of cloth joints, because the following processes are basically long car production. The consequence of not binding is that if the cloth joints are broken in the steamer in the production process, it is a very troublesome thing

Desizing is to remove the size on the warp yarn when weaving. The thin fabric can be desized directly by desizing machine. Cold batch desizing is the best choice for afterweight and elastic fabric. Enzyme desizing will be more thorough

Singeing, cotton need singeing, in order to remove the length of the yarn on the hair, thin cloth fire on the line, such as 7 * 7 thick card need to add iron plate (also known as cylinder) to burn fresh

Setting: the pre-treatment setting only aims at the elastic cloth, and the door width is different after desizing and singeing, and it can only be set if it is smaller than the finished door width. The pre-treatment setting should not be larger than the finished door width, and it is better to be close to and equal to the finished door width

Bleaching, as long as pay attention to the unity of whiteness on the line, cotton generally choose hydrogen peroxide bleaching, also known as oxygen bleaching

Mercerizing, mercerizing should pay attention to the door width. When mercerizing, the door width is too small to be opened, and the finishing can not be opened. If it is too large, the back can not be retracted. Mercerizing is best controlled to be consistent with the door width of the finished product. In this way, the door width will be retracted when dyeing, and the finishing can be opened, and the preshrinking can be controlled properly

After mercerization, if there is a requirement for sanding, then sanding, the end of pretreatment

Key points for attention: for thin and thin cloth, check cloth, weft skew, curling, etc. should be controlled. For large grid, when singeing, attention should be paid to the direction of the fire opening, which should not be penetrated, that is, the fire opening should not be perpendicular to the cloth surface, so as to avoid damage to the strength. The finished product is black. Attention should be paid to baking foreign fiber after singeing. The finished door width should be close to or equal to the finished door width

Bleaching, as long as pay attention to the unity of whiteness on the line, cotton generally choose hydrogen peroxide bleaching, also known as oxygen bleaching

Mercerizing, mercerizing should pay attention to the door width. When mercerizing, the door width is too small to be opened, and the finishing can not be opened. If it is too large, the back can not be retracted. Mercerizing is best controlled to be consistent with the door width of the finished product. In this way, the door width will be retracted when dyeing, and the finishing can be opened, and the preshrinking can be controlled properly

（2） Dyeing part:

Cotton fabric dyeing is now based on long car continuous pad dyeing, vat dyeing is no longer the mainstream

Dyeing is a simple process, because only one rolling mill is enough, but it is also the most difficult process, because the color control of dyeing is not only known, but also has many unknown things in it, such as the stability of dye at different temperatures, the control of steam, the control of rolling pressure, etc. it is a very fine work

The long car dyeing is divided into two parts: front car dyeing and back car fixing. The dyeing methods vary according to the types of dyes selected. The dyes are generally reactive, Shilin, vulcanization and paint. They have their own advantages and disadvantages. Generally, they depend on the color of the customers, and can not be replaced with each other. Shilin has the best color fastness, but it is expensive, and it is not suitable for dyeing dark colors, The color of light color is not bright enough. In addition to the cost of dyeing dark color, it is difficult to control the dyeing of dark color compared with reactive dyes, which is easy to cause cloth surface problems. The color fastness of reactive dyes is worse than that of Shilin, but the dyeing of light color is more gorgeous, and the cost of dark color is less. Vulcanization is the worst, the color fastness is not very good, and the prohibition of azo is not up to the standard, But now there is a kind of liquid vulcanization (also known as water vulcanization) that can meet the standard of azo, but the price is close to that of Shilin, the dyeing is not easy to control, and it can not be popularized. Only a few people pursue its fading effect and use it. The coating is not comparable, and its fading is very serious

It can be used flexibly with Shilin and reactive agent to get different washing effect (general Shilin or reactive primer, coating surface color can solve the white spot problem of single dye coating, and the cost will increase accordingly)

The reactive dye is fixed with salt and soda, the reactive dye is fixed with hydrogen peroxide, and the sulfurized dye is fixed with high temperature cooking. The water temperature must be above 95 ℃

After dyeing, it is decided whether to fix the color by baking according to the fading requirement of color fastness. The baking temperature is about 195-210 ℃

Dyeing can not be 100% good, repair color, stripping color is inevitable. Slight adjustment, such as shallow set of paint, deep with soda ash wash

（3） After finishing part:

Because the cotton cloth in the pretreatment and dyeing after a lot of long car, warp stretch, weft shrinkage, feel is rough, finishing is to solve these problems.

Soft and stretch, soft and stretch if there is no setting machine, should be carried out separately, first soft to improve the handle, in the stretch. The contraction of the weft to open. There is a setting machine can be done at one go. But the best way to go elastic fabric setting process

Preshrinking: let the cloth to shrink the extended part of the production process to the allowable range of clothing cutting through the principle of preshrinking machine's blanket, hot expansion and cold contraction. The elastic cloth should be controlled at 3% warp and 5% weft. The non elastic cloth should be controlled at 3% warp and 3% weft

After finishing, according to the requirements of customers, twill cloth should pay attention to whether it needs to be skewed, whether the weft skew of plain cloth is up to the standard (generally, the weft skew of plain cloth should be controlled within 3%, and the grid skew of plaid cloth should be controlled, preferably close to 0), and whether weft adjustment is needed

Factories can also according to their own equipment, can also air soft cleanser. Of course, there are additional costs

（4） Finished product inspection part:

After finishing, the finished fabric is tested, shrinkage, color fastness, and other internal indicators required by customers. If the color indicators are qualified, the finished product can be inspected. Most customers agree with the American four point standard inspection (Chinese national standard is similar to it, but the defects are too fine to remember and use), and the qualified products can be packaged, The fabric can be sent to the garment factory