How to Choose the Right Textile Auxiliaries for Your Needs

In the textile industry, in the various processing procedures from spinning, spinning, weaving, printing and dyeing to finished products, different auxiliary chemicals are required according to the performance of various fibers to improve the quality of textiles, improve processing effects, increase production efficiency, and simplify Process, reduce production costs and give textiles various excellent application properties. This auxiliary chemical is commonly known as textile dyeing and finishing auxiliaries.

The pre-treatment process of printing and dyeing includes fiber singeing, desizing, scouring, bleaching, mercerizing and other processing processes. It is necessary to add penetrants, emulsifiers, cleaning agents and other surfactants, such as organic sulfate, sulfonate and polyoxyethylene. Mainly ether.

Penetrants, wetting agents, penetrants commonly used in the textile industry include butyl ricinoleate sulfate, butyl naphthalene sulfonic acid sodium salt, etc. In neutral solution, dioctyl sodium succinate sulfonate has a particularly strong penetrating ability; in acid solution, in addition to the above varieties, fatty alcohol polyoxyethylene ether or alkylphenol polyoxyethylene ether is commonly used; and in strong alkaline In the solution, for example, the mercerizing process requires the use of shorter carbon chain sulfates such as octanol sulfate.

Emulsifiers are often oiled in order to improve the lubricating properties of silk and yarn in the spinning process. However, the oil must be removed before printing and dyeing, so as not to affect the dyeing. Therefore, it is necessary to add emulsifiers in these textile oils, or add emulsifiers in the cleaning bath to ensure the removal of oil spots, generally nonionic surfactants are used.

Cleaning agents, namely detergents and detergents, remove oily stains on textiles. In the past, soap was the mainstay, but now a variety of synthetic detergents and non-ionic surfactants are used, including slightly more expensive oleic acid amide derivatives. . In addition, there are enzymes used to promote starch hydrolysis during desizing; activators and anticorrosive agents added during bleaching speed up the bleaching process and increase the whiteness without corroding the equipment. At present, it has been developed to complete desizing, scouring and bleaching in one bath, and a new compound powerful cleaning aid is used.

There are many types of textile dyes, and the dyeing process is different, and the corresponding supporting auxiliaries are needed. Therefore, there are many kinds of such auxiliaries, mainly as follows

2.1.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 nitrilotriacetate and sodium ethylenediaminetetraacetate.

2.2.Solvents and co-solvents

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

2.3.Reducing agent and oxidizing agent

 When using vat dyes, you must first use a reducing agent to dissolve vat dyes. Commonly used are sodium hydrosulfite (sodium dithionite), hanging white block (sodium formaldehyde sulfoxylate), and thiourea dioxide. When the vat dye is anti-dyeing, a mild oxidizing agent, sodium nitrobenzene sulfonate, can be used. This product can also be used in printing paste to protect the dye from the possible reducing components in the paste.

2.4.Fixing agent and color developing

aid When dyeing with direct dyes, acid dyes and reactive dyes, use fixing agent before and after dyeing to improve the amount of color and fastness. Fixing agent mainly uses amine salt and polymer quaternary ammonium salt. Dyes for printing sometimes use color-developing additives, such as diethylethanolamine when steaming and color-developing fastamine.

2.5.Dispersant, also known as diffuser

 When printing and dyeing with disperse dyes and vat dyes, dispersants and protective colloids should be added to ensure uniform dyeing and prevent stains. Commonly used dispersants are sulfonated oil (Taikoo oil, Turkish oil), sodium alkyl or long-chain amidobenzene sulfonate, alkyl polyoxyethylene ether, sodium lignin sulfonate, naphthalenesulfonic acid formaldehyde condensate, oleoyl Polyamino carboxylate and the like.

2.6.Leveling agent, namely leveling agent

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

2.7.Defoamer

Used to remove foam caused by surfactants in the printing and dyeing process. In the past, tributyl phosphate, octanol, etc. were generally used, but now they have all used organic stone compounds.

2.8.Defoamer

Used to remove foam caused by surfactants in the printing and dyeing process. In the past, tributyl phosphate, octanol, etc. were generally used, but now they have all used organic stone compounds.

2.9.Printing paste and thickener

In the past, natural slurries were used, but now they have tended to use semi-synthetic or synthetic slurries, such as starch ether, sodium alginate, etherified locust bean powder, cellulose esters, polyvinyl alcohol, and polyacrylates. The synthetic slurry has high consistency and low dosage, which can make the color of printing deep. The chemical structure of the thickener is macromolecular polyethylene glycol bisether or diester, or 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 acrylic esters can be used. It is required to have strong adhesion, that is, good abrasion fastness, soft hand feeling, and not easy to yellow under high temperature and light. At present, high-quality general-purpose adhesives are polyacrylate copolymers with self-crosslinking groups and polyurethanes.

After the printing and dyeing process is completed, the fabric is generally washed to remove the floating color to improve the color fastness. The synthetic cleaning agent used varies with the dye and the printing and dyeing processing method. For example, after the disperse dye dyes the polyester-cotton fabric, it is necessary to remove the floating color on the polyester. , And to prevent the cotton fiber from being polluted, special non-ionic cleaning agents must be used.

3.1.Finishing agent Chemicals

used to improve the appearance, feel, shrinkage rate of fabrics, stabilize appearance, prolong life, waterproof, fireproof, antifouling, mildew and other chemicals. Resin finishing agent, the most important finishing agent, is a polymer compound that can bond with the hydroxyl group of cellulose to achieve a longer-lasting anti-wrinkle and non-ironing effect. When mixed with an appropriate softener, it can improve the feel of the fabric. Commonly used resins are urea-formaldehyde resin, melamine-formaldehyde resin, dimethylol ethylene urea resin, dimethylol dihydroxy ethylene urea resin and bishydroxy ethyl sulfone. Among them, dimethylol dihydroxy ethylene urea resin is the most widely used, which is formed by the condensation of glyoxal, urea and formaldehyde. Penetrants, catalysts (commonly used metal salts, ammonium salts or organic amine salts) and feel modifiers should be added to the resin finishing fluid. The latter is usually a softener. The newly developed resin finishing agent, polyurethane, has a slightly higher price, but has high styling performance, no residual formaldehyde, and does not cause skin allergies.