Printing and dyeing auxiliaries are auxiliaries used in the process of fabric printing and dyeing, which can improve the effect of printing and dyeing. They include printing auxiliaries and dyeing auxiliaries. Printing auxiliaries include thickeners, adhesives, cross-linking Agents, emulsifiers, dispersants, and other printing auxiliaries.
Classification
Printing and dyeing auxiliaries can be divided into printing auxiliaries and dyeing auxiliaries. Printing auxiliaries include binders, thickeners, cross-linking agents, emulsifiers, softeners, diffusing agents and defoaming agents, etc. Dyeing auxiliaries include leveling agents, color fixing agents, dispersants, optical brighteners, softeners,s, etc.
scouring aid
Desizing, scouring, bleaching, and mercerizing of fabrics are all important processes before fabric printing and dyeing, collectively referred to as scouring.
Scouring is to boil the desizing cotton fabric in a 10g/L dilute caustic soda solution for several hours to remove impurities such as cottonseed hulls, waxes, pectin substances, nitrogen-containing substances, and pigments on the cotton fibers and residues. The slurry on the cloth can obtain a good appearance and its water absorption performance, and effectively improve the printing, dyeing, and finishing effect.
Synthetic fibers do not need scouring, but blended fabrics with cotton fibers still need scouring, but soda ash should be used instead of caustic soda, or a caustic soda solution with a lower concentration should be used.
Some surfactants need to be added to the scouring liquid to improve the permeability of the lye, promote the emulsification of the wax, and further shake and disperse the impurities from the fibers in the scouring liquid.
Printing auxiliaries
Pigment printing is to use the film-forming effect of the adhesive to firmly adhere the insoluble dye to the fabric, so as to achieve the purpose of coloring.
The adhesive is the main component of paint printing paste, and it is a polymer film-forming substance. It adheres the paint to the fabric through film-forming. Therefore, the adhesive is required to have good adhesion, reproducibility, and aging resistance to the fabric. , Solvent resistance, acid and alkali resistance, chemical resistance, clear and transparent film formation, no discoloration after printing, no damage to fibers, certain elasticity, good hand feeling, and easy to remove from the printing machine.
Thickener is another important component of pigment printing paste. It has the functions of thickening dyeing, promoting adhesion and emulsification, and obtaining a uniform, soft and clear patterns on printed fabrics. Not only can it improve the amount of color and brightness, but also no or less kerosene is used in the printing paste. There are two types of synthetic thickeners: anionic and non-ionic. The former has strong adaptability and can be used for anti-dyeing and dyeing printing, but the thickening effect is poor; the latter has a high viscosity and thickening effect, which is suitable for printing fabrics. The color brightness, scrub fastness, and softness of the hand are not adversely affected.
The main function of the cross-linking agent is to improve the fixing ability of the adhesive. The use of printing has good firm performance, and it can also reduce the curing temperature, combined with the actual short curing time, but the amount should be appropriate, otherwise, it will cause the fabric to feel bad.
The emulsifier is added in order to obtain good emulsification and thickener, generally using end-blocked alkylphenol polyoxyethylene ether, and then blocking the end-group with isocyanate. Pigment printing auxiliaries also include softeners, diffusing agents, and defoaming agents.
Dyeing Auxiliary
Dyeing agent Dyeing is the main body of the dyeing process. Different fiber fabrics use different variegated agents, and according to different processes, dye processing auxiliaries include cosolvents, dispersants, color developing agents, and phthalocyanine auxiliaries. The dyes used in dyeing are not direct dyes, vat dyes, reactive dyes, phthalocyanine dyes, and insoluble azo dyes.
Leveling agent includes natural fiber leveling agent, synthetic fiber leveling agent and blended fabric leveling agent, etc. As a leveling agent, the condition is that the dye can be slowly absorbed by the fiber or the dark part of the dye can be changed to light color. Partial spread without reducing dye fastness. All auxiliaries with retarding and migration effects are called leveling agents.
There are three types of color-fixing agents, cationic surfactants, non-surface-active quaternary ammonium salts, and resin-based color-fixing agents. It is large and insoluble in water, so as to improve the firmness of dyeing.
The dispersant is an indispensable auxiliary agent in dye processing and dye application. It can disperse dye particles to about 1 μm, which helps the
The particles are crushed to maintain the dispersion stability of the dye. The dispersants are mostly various types of surfactants, including anionic, cationic, nonionic, amphoteric, and polymer types.
The fluorescent whitening agent is referred to as FWA. It uses optical complementary color to make the yellowish-brown pigment on the fabric that cannot be removed by chemical bleaching white. Due to the enhanced luminosity, the whiteness is more beautiful.
Most of the softeners have fragrances, and most of the fragrances and dyes are petroleum derivatives and contain benzene. If the manufacturer uses raw materials with poor grades, it will also cause irritation to the skin. During the washing process of clothes, fine fibers are often entangled, tangled together, or even broken. After the clothes are washed many times, the alkaline effect of the detergent affects the inherent smoothness, extensibility, and elasticity of the fibers, showing The only thing is that the whole clothes look old and shapeless, and feel blunter to the touch. The more the clothes are washed, the more obvious this feeling is. The function of the fabric softener is to evenly apply a protective film to the surface of the fabric fibers, and the friction coefficient between the fibers is reduced due to the adsorption of the softener on the surface of the fibers.
