What are the printing and dyeing auxiliaries

There are many varieties of textile dyes, the dyeing process is different, and corresponding auxiliary auxiliaries are required. Therefore, there are many varieties of such auxiliaries, mainly including the following:

1. Water softener: metal ion chelating agent

Heavy metal ions in water often affect the color or solubility of dyes. We can use water softeners to remedy them. Commonly used water softeners include sodium hexametaphosphate, sodium ammonium triacetate and sodium ethylenediaminetetraacetate.

2. Solvents and cosolvents

When using or preparing liquid dyes, some dyes need to be filled with solvents to help them dissolve, such as ethylene glycol, diethylene glycol, glycol ethers, formamide, thiodiethanol, etc. As a dye solvent; when dyeing with phthalocyanine blue, use the matching co-solvent and copper salt, and use the co-solvent sodium benzyl sulfamate for vat dyes.

3. Reducing and oxidizing agents

When using vat dyes, a reducing agent must be used to dissolve the vat dyes. Commonly used are sodium hydrosulfite (sodium hydrosulfite), hanging white block (sodium formaldehyde sulfoxylate), and thiourea dioxide. Sodium m-nitrobenzenesulfonate, a mild oxidant, can be used for vat dye prevention. This product can also be used in printing pastes to protect the dyes from reducing components that may be contained in the paste.

4. Fixing agent and color developing auxiliaries

When dyeing with direct dyes, acid dyes and reactive dyes, a fixing agent is used before and after dyeing, which can improve the color yield and fastness. The color fixing agent mainly uses amine salts and high molecular quaternary ammonium salts. Printing dyes sometimes use color-developing auxiliaries, such as diethylethanolamine when tetramine is steamed for color development.

5. Dispersing agent, also known as diffusing agent

When printing and dyeing with disperse dyes and vat dyes, dispersants and protective colloids should be added to ensure uniform dyeing and prevent color spots. Commonly used dispersants are sulfonated oil (Swire oil, Turkish oil), alkyl or long-chain amido benzene sulfonate, alkyl polyoxyethylene ether, sodium lignosulfonate, naphthalene sulfonic acid formaldehyde condensate, oleoyl Polyamine carboxylates, etc.

6. Leveling agent, that is, leveling agent

Polyoxyethylene ether surfactants are commonly used as leveling agents for dyes, cationic surfactants are used for cationic dyes, and anionic surfactants are used for acid dyes.

7. Matting agent

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

8. Defoamer

It is used to remove foam caused by surfactants in the printing and dyeing process. Originally, tributyl phosphate, octanol, etc. were generally used, but now they have all used the compound of organic stone.

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 bean powder, cellulose ester, polyvinyl alcohol and polyacrylate. The synthetic paste has high consistency and low dosage, which can make the printing result darker. The chemical structure of the thickener is macromolecular polyethylene glycol diether or diester or polyacrylate copolymerized by acrylate.

10. Adhesives for printing and dyeing

Various synthetic latexes such as copolymers of butadiene, styrene, acrylonitrile, vinyl acetate, vinyl chloride, and acrylates can be used. It is required to have strong adhesion, that is, good abrasion fastness, soft hand feel, and not easy to yellow under high temperature and light. At present, the high-quality general-purpose adhesives are polyacrylate copolymers with self-crosslinking groups and polyurethanes.