What are the pre-treatment methods for dyeing fabrics to obtain dark colors?

1 Strengthen the impurity and decontamination treatment of the contaminated objects

Adequate pre-treatment, good fabric wettability, large capillary effect, the diffusion ability of dye molecules to the dyed matter may increase, thereby increasing the dye uptake rate. Therefore, strengthening the impurity removal and decontamination treatment of the dyed material can achieve the above-mentioned purpose.

2 Mercerizing treatment of cotton fabric

After mercerized cotton fabric, its ability to absorb dyes is significantly improved. Compared with cotton fabric without mercerizing treatment, it can achieve a medium-dark effect and improve surface gloss.

3 Alkali reduction treatment of polyester fabric

Polyester macromolecules have high crystallinity, tight fiber structure, high refractive index and surface reflectivity, smooth fiber surface, mainly specular reflection of light, after dyeing with disperse dyes black, because a large amount of reflected light is white from the surface of the fabric Light enters people’s sight, so dark black is harder to get. After alkali reduction treatment, the original smooth surface of polyester becomes rough surface, forming uneven and irregular reflection layer, which is the etching effect we often say, and produces a certain dark effect, and the fabric after the reduction treatment The freedom of movement increases, and the adhesion of the dye increases.

4 Application of low temperature plasma technology

Plasma technology belongs to the method of processing the surface of the fabric, and belongs to the dry-cleaning physical processing of modern dyeing technology. For example, after the plasma-treated polyester fiber is grafted and polymerized, a low-refractive-index film is formed on the surface of the fiber, which can significantly increase the dye uptake and the depth of color; another example is the plasma treatment of the hard-to-dye linen fabric. The capillary effect is 1 to 1.5 times that of untreated, and the amount of dye adsorption is greatly increased. It is easy to dye deep and dense colors and the dark effect is obvious.

5 Ultrasonic technology treatment

Ultrasound is a vibration wave that human ears cannot perceive. Sound waves with a normal frequency of 104~109Hz are called ultrasonic waves, and those with a frequency greater than 109Hz are called special ultrasonic waves or microwave ultrasonic waves. After the fabric is treated with ultrasonic technology before dyeing, the fiber concentration is loose to a certain extent, which increases the specific surface area inside the fiber, thereby increasing the amount of dye absorption by the fiber, increasing the dye uptake rate of the fabric, and achieving a medium-dark effect. . After research, this technology has obvious effect on wool fibers with scaly layers and linen fabrics with tight surface structure.