Key technology of fabric discharge printing

Key technology of fabric discharge printing

Discharge printing is also called engraving. Refers to the printing process on the dyed fabric by printing a color paste that can eliminate the "ground color" and produce a white or colored pattern. In the case of printing, a color paste containing a destructible color is printed on the ground fabric, and after drying, it is printed with a flower dye containing a discharge agent or a discharge-resistant agent. In the post-treatment, the dye at the printing place is destroyed and decolored, forming a white pattern on the color ground or a colored pattern formed by dyeing the color dye, which is also called color drawing or color drawing. Due to the more detailed and realistic pattern of the dyeing and printing, the pattern is rich in layers, the color contrast is strong, the outline is clear, and the color is full and more and more people pay attention to it. It uses a reducing agent and an oxidizing agent to destroy the ground color of the colored fabric to obtain a partially achromatic or colored pattern. The chemical discharge agents used vary from fabric to fabric. Discharge printing can be used for both cloth and finished garments.

1, color paste modulation

The paste and dye are thoroughly stirred well, and after filtration, the filtered processed tin is added. However, it should be noted that the processing tin and the dye cannot be stirred at the same time, otherwise the dye is difficult to dissolve, which may cause the phenomenon of blocking the net, color point, and plugging during printing, when preparing the dyeing of the white pulp or the light color. To add an appropriate amount of reactive blue, the processed tin must be thoroughly stirred and filtered before use; the amount of tin to be processed according to the pattern is small, and if the amount is small, the pattern is blurred and the outline is unclear.

2, control the temperature

The temperature of the printing machine drying room should not exceed 100 °C under normal conditions. It is better to dry at low temperature and the drying temperature is too high to reduce the discharge effect of processing tin. The dyeing bottom should not exceed 120 °C, the bottom of the bottom should not exceed 100 °C, low temperature drying is appropriate, and it should not be stopped during the drying process. The processing tin is highly corrosive to the screen and equipment. Under normal circumstances, the production is 5,000 meters. It is necessary to check the screen to prevent sand leakage and the lines are not clean. The pressure adjustment of the scraper of the printing machine should be uniform, and it is necessary to make a good version. The whitening paste or synthetic gelatin is generally used for the dyeing paste, and the stripping property is worse than that of sodium alginate. Therefore, it is better to use a rope-type washing machine and strengthen the reduction and cleaning to make the cloth surface fresh, the color is pure, and the flower shape is clear. .

The anti-discharge of polyester fabric can be divided into alkali extraction and tin extraction, but the effect of processing tin on polyester silk fabric is better. Because the processed tin is modified stannous chloride, its insoluble in water is not easily oxidized by air, which increases the stability of the color paste, thereby improving the quality of the printing.

Anti-discharge printing of cotton cloth: It can be dyed with reactive dyes, can be dyed with vinyl sulfone-based reactive black dye, dried and printed, and printed with a wet cover printing method. ). The base color (black) is dyed by a rolling-baking process, and the dye is not easily fixed. Overprinting on an unfixed black background, drying, steaming, and simultaneous color development, the black background is easily converted into a black-reddish phase.

Dyeing and printing of silk and wool textiles: The ground color can be dyed with acid dyes and reactive dyes with azo structure. The ground color of polyester and acetate textiles can be dyed with disperse dyes with azo structure, and the discharge agent is usually strong. Reducing agent, commonly used stannous oxide, discharge printing is mainly used for deep ground printing, printing effect is good.