To obtain patterns on the ground color of polyester fabrics, dye-resistant printing art is usually adopted instead of discharge art. Because polyester fabrics are usually dyed with disperse dyes, when the dyeing process is completed, after the ground dyes diffuse into the polyester, it is difficult to completely destroy them by the discharge printing method.

Dye-resistant printing on polyester fabrics mainly adopts first padding disperse dye solution or full-floor printing, drying at low temperature (not more than 100°C) to ensure that the fiber is not dyed with dye, and then printing with a dye-resistant printing paste that can damage the ground dye; Or adopt the method of printing the anti-dyeing paste on the fabric first, drying it, and then overprinting the ground color paste.

The anti-dye printing of polyester fabric generally cannot use the method of printing anti-dyeing paste, drying, and then padding the ground color dyeing solution.

Because polyester is a phobic fiber, its ability to adhere to the color paste is poor. If the color paste is printed and then dipped in the pad dye solution, the color paste will permeate on the fabric. At the same time, the anti-dyeing agent will continue to enter the dye solution and it is difficult to dye well. Ground color.

The method of first soaking the pad dyeing solution (or printing all over the ground), baking at low temperature and then printing the anti-dyeing paste is called foot-type anti-dye printing, and it is also called discharge-type anti-dye printing.

Another method of anti-dye printing is to print anti-dyeing paste on the fabric first, then cover-print the whole ground color paste, and finally bake it.

The characteristic of this method is that the pattern and ground color were completed last time on the printing machine, so it is called the "anti-print" art of footwork wet overprinting. Wet "anti-print" art can often get better anti-dyeing effect.

According to the structure of disperse dyes, some can be destroyed by reducing agents, and some can be combined with a complex compound that increases the weight of the compound to prevent the dye from diffusing into the fiber.

Available reducing anti-dyeing agents include hydroxymethyl sulfinate, stannous chloride, and thiourea oxide. The most common genus salt that can fully complex with certain disperse dyes is copper salt.

Non-volatile fatty acids such as alcoholic acid or ammonium hydrogen phosphate adjust the pH of the dye solution to 5.5, and the anti-dye salt S can also be changed to 2g/L sodium chlorate, but it must be noted whether it has any effect on the dispersed dyes.

If the pad dye solution is not used for printing all over the floor, the anti-migration agent in the dye solution can be changed to a medium viscosity sodium alginate paste to make a color paste.

The printing equipment can be a cylinder screen printing machine or a roller printing machine. In order to ensure uniform printing, different numbers of cylinders should be selected according to different fabrics or the engraving depth of the copper roller should be controlled.

Dye-proof printing with hydroxymethyl sulphite method

Hydroxymethyl sulfinate (TelijieTM) is a strong reducing agent type anti-dyeing agent with good solubility. It can be used for the anti-white or color anti-dye printing of disperse dyes. It is soluble in weak acid solution. It decomposes at 80~100℃, and has strong reducing energy, which can be used to prepare acidic anti-dye printing paste; zinc hydroxymethanesulfinate (Zn(SO2CH2OH)) can obtain good anti-dyeing effect. Many disperse dyes are easy to Because of its destruction, it is not often used to prepare disperse dye colored anti-dyeing paste.

Disperse dyes that can be damaged by hydroxymethanesulfinate (TelijieTM) and other ground colors are all dyes with azo structure. Their decomposition products should be colored and easy to wash off.

The original paste can be etherified locust gum or a mixed paste of dextrin and starch. When Dekelin is a reduction inhibitor, 2~3% organic acid ester type acid release agent should also be added to the anti-slurry, which is not like free acid. That will reduce the stability of the color paste.

The polyol in the anti-pulp helps to prevent the swelling effect of polyester, and it is more effective to increase the amount of reducing agent. Add etherifying agent W3~5%, also beware of the effect.

Add reduction-resistant disperse dyes and fatty acid derivative fixing accelerators, and 2% anti-dyeing salt S in the anti-dye printing paste to prevent the colored disperse dyes from being affected by the remaining reducing substances during the steaming process. influences.

The fabric is steamed after printing, and steaming at 170°C under normal pressure can obtain fine pattern contours. During the steaming process, the ground dye is destroyed, and the colored dye dyes the fiber. After the fabric is steamed and fixed, it can be washed at 70°C for 10 minutes in a reducing cleaning solution composed of conventional safety powder (2~3g/L) and 36°Be caustic soda solution (4~6ml/L), and then fully washed.

If Dekelin is used as an anti-dyeing agent, an appropriate amount of chelating agent can be added to the reducing cleaning solution.