textile dyeing and finishing auxiliaries - Printing and dyeing auxiliaries 2

Printing and dyeing auxiliaries

    There are many types of textile dyes and different dyeing processes. Corresponding auxiliary agents are needed. Therefore, there are many types of such auxiliary agents, mainly the following:

    2.1 Water softener: metal ion chelator

    Heavy metal ions in water often affect the color of the dye or its dissolving properties. We can use water softeners to remedy them. Common water softeners include sodium hexametaphosphate, sodium triacetate, and sodium ethylenediamine tetraacetate.

    2.2 Solvents and co-solvents

    When some dyes are used or formulated with liquid dyes, filling solvents are needed to help them dissolve, such as ethylene glycol, diethylene glycol, glycol ethers, formamide, thiodiethanol, etc. As a dye solvent; when dyeing with phthalocyanine blue, the auxiliary co-solvent and copper salt are used, and the reducing dye is a co-solvent sodium benzylaminobenzene sulfonate.

    2.3 Reducing agents and oxidants

    The vat dye must be dissolved with a reducing agent before use. The vulcanizing powder (sodium dithionite), hanging white block (sodium formaldehyde sulfoxylate), and thiourea dioxide are commonly used. Vat dyes can be used as a mild oxidant sodium m-nitrobenzene sulfonate for anti-dyeing. This product can also be used in printing pastes to protect the dyes from the reducing components that may be present in the paste.

    2.4 Fixing agents and color development aids

    When dyeing with direct dyes, acid dyes, and reactive dyes, treatment with a fixing agent before and after dyeing can improve the amount of color and fastness. Fixing agents are mainly amine salts and polymer quaternary ammonium salts. Printing dyes sometimes use color development aids, such as diethylethanolamine for fast amine steam color development.

    2.5 Dispersant, also known as dispersant

    Dispersants and protective colloids should be added when printing with disperse dyes and vat dyes to ensure uniform dyeing and prevent stains. Commonly used dispersants are sulfonated oil (Swire oil, Turkish oil), alkyl or long chain sodium amidobenzenesulfonate, alkyl polyoxyethylene ether, sodium ligninsulfonate, naphthalenesulfonic acid formaldehyde condensate, oleyl Polyamine carboxylate and the like.

    2.6 Levelling agent

    Polyoxyethylene ether surfactants are commonly used as dyes for levelling agents. Cationic dyes should use cationic surfactants and acid dyes should use anionic surfactants.

    2.7 Matting agent

    Compared with natural fibers, the surface of synthetic fibers is too smooth and the reflectance is too high. Therefore, titanium dioxide and zinc sulfide must be added to improve it.

    2.8 Defoamer

    Used to remove foaming caused by surfactant during printing and dyeing. Originally, tributyl phosphate, octanol, etc. were generally used, and now the compound of organic stone is used.

    2.9 Printing paste and thickener

    In the past, natural pulp was used, but now it has tended to use semi-synthetic or synthetic pulp, such as starch ether, sodium alginate, etherified locust powder, cellulose ester, polyvinyl alcohol and polyacrylate. Synthetic paste has high consistency and low dosage, which can make the color obtained by printing deep. The chemical structure of the thickener is a high molecular polyethylene glycol diether or diester, or a polyacrylate copolymerized with acrylate.

    2.10 Adhesives for printing and dyeing

    Various synthetic latexes such as copolymers of butadiene, styrene, acrylonitrile, vinyl acetate, vinyl chloride, and acrylate can be used. Requires strong adhesion, that is, good abrasion resistance, good softness, and not easy to yellow at high temperatures and under light. At present, high-quality universal adhesives are polyacrylate copolymers with self-crosslinking groups and polyurethanes.