In the textile industry, in various processing steps from spinning, spinning, weaving, printing and dyeing to finished products, different auxiliary chemicals need to be used according to the properties of various fibers to improve the quality of textiles, improve processing effects, and increase production. efficiency, simplify the process, reduce production costs and give textiles various excellent application properties. This kind of auxiliary chemicals is commonly known as textile dyeing and finishing auxiliaries. Dyeing and finishing auxiliaries are often divided into three categories: printing and dyeing pre-treatment agents, printing and dyeing auxiliaries, and finishing agents according to the steps and uses of dyeing and finishing processing.
1. Pre-treatment agent for printing and dyeing
The pre-treatment process for printing and dyeing includes fiber singeing, desizing, scouring, bleaching, mercerization and other processing processes. It is necessary to add penetrants, emulsifiers, cleaning agents and other surfactants, mainly organic sulfates, sulfonates and polyoxyethylene ethers.
Penetrating agents, wetting agents: Commonly used penetrating agents in the textile industry include sulfate ester of butyl ricinoleate, butyl naphthalene sulfonate sodium salt, etc. In neutral solutions, sodium dioctyl sulfonate sulfonate has particularly strong penetrating ability; in acidic solutions, in addition to the above varieties, fatty alcohol polyoxyethylene ethers or alkylphenol polyoxyethylene ethers are commonly used; while in strongly alkaline solutions In solution, such as mercerizing process, sulfate esters with shorter carbon chains such as octanol sulfate should be used.
Emulsifiers are often oiled in order to improve the lubrication properties of silk and yarn during the textile process. However, oil must be removed before printing and dyeing to avoid affecting dyeing. Therefore, emulsifiers must be added to these textile oils in advance, or emulsifiers must be added to the cleaning bath to ensure the removal of oil spots. Generally, nonionic surfactants are used.
Cleaning agents, namely detergents and detergents, are used to remove oil stains on textile items. In the past, soap was the main method, but now various synthetic detergents and non-ionic surfactants are used. agents, and include slightly more expensive oleic acid amide derivatives.
In addition, there are enzymes used to promote starch hydrolysis during desizing; activators and anti-corrosion agents added during bleaching can speed up the bleaching process and increase the whiteness. Does not corrode equipment. At present, it has been developed to complete desizing, scouring and bleaching in one bath, and new compound powerful cleaning additives are used.
2. Printing and dyeing auxiliaries
There are many varieties of textile dyes, and the dyeing processes are different. Corresponding supporting additives are required, so there are many varieties of such additives, mainly including the following:
1. Water softener: metal ion chelating agent heavy metal ions in the water It often affects the color or solubility of dyes. We can use water softeners to remedy this. Commonly used water softeners include sodium hexametaphosphate, sodium nitrilotriacetate, and sodium ethylenediaminetetraacetate.
2. Solvents and co-solvents: When using or preparing liquid dyes, some dyes need to be filled with solvents to help dissolve them, such as ethylene glycol, diethylene glycol and diethylene glycol. Glycols, glycol ethers, formamide, thiodiethyl alcohol, etc. can be used as dye solvents; when dyeing with phthalocyanine blue, matching cosolvents and copper salts must be used, and for vat dyes, the cosolvent benzyl aminobenzene sulfonate is used sodium acid.
3. Reducing agent and oxidizing agent When using vat dyes, a reducing agent must be used to dissolve the vat dyes. Commonly used ones include insurance powder (sodium dithionite), sodium dithionite (formaldehyde) Sodium bisulfite), thiourea dioxide. Sodium m-nitrobenzene sulfonate, a mild oxidant, can be used to resist dyeing with vat dyes. This product can also be used in printing slurries to protect the dyes from the reducing components that may be contained in the slurry.
4. Fixing agents and color development auxiliaries When dyeing with direct dyes, acid dyes and reactive dyes, use fixing agents before and after dyeing to increase the amount of color and Fastness. Fixing agents mainly use amine salts and polymer quaternary ammonium salts. Printing dyes sometimes require the use of color development aids, such as diethyl ethanolamine when steaming fast amines to develop colors.
5. Dispersant, also known as diffusion 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 include sulfonated oil (Taikoo oil, Turkish oil), sodium alkyl or long-chain amide benzene sulfonate, alkyl polyoxyethylene ether, sodium lignin sulfonate, naphthalene sulfonic acid formaldehyde condensate, oleyl Polyamine carboxylate, etc.
6. Leveling agent, that is, leveling agent dyes commonly use polyoxyethylene ether surfactants as leveling agents. Cationic dyes should use cationic surfactants, and acid dyes should use cationic surfactants. Use anionic surfactants.
7. Matting agent Compared with natural fibers, the surface of synthetic fibers is too smooth and the reflectivity is too high, so titanium dioxide, zinc sulfide, etc. must be added to improve it.
8. Defoaming agents are used to remove foam caused by surfactants during the printing and dyeing process. In the past, tributyl phosphate, octanol, etc. were generally used, but now organic stone compounds are used.
9. Printing slurries and thickeners used to use natural slurries, but now they tend to use semi-synthetic or synthetic slurries, such as starch ether, sodium alginate, ether Chemical locust bean powder, cellulose ester, polyvinyl alcohol and polyacrylate, etc. Synthetic slurry has high consistency and low dosage, which can make the printing color darker. The chemical structure of the thickener is polymer polyethylene glycol diether or diester or polyacrylate copolymerized by acrylate.
10. Adhesives for printing and dyeing can use various synthetic latexes such as copolymers of butadiene, styrene, acrylonitrile, vinyl acetate, vinyl chloride and acrylate. Strong adhesion is required, that is, abrasion fastness.�, soft to the touch, not prone to yellowing at high temperatures and under light. At present, the higher quality general-purpose adhesives are polyacrylate copolymers with self-crosslinking groups and polyurethanes.
3. Cleaning agent for post-printing and dyeing treatment
After the printing and dyeing process is completed, the fabric generally needs to be cleaned to remove floating colors to improve the dye fastness. The synthetic cleaning agents used vary with the dyes and printing and dyeing processing methods. For example, after dyeing polyester-cotton fabrics with disperse dyes, both polyester and polyester must be removed. To prevent the floating color from staining the cotton fiber part, a special non-ionic cleaning agent must be used.
1. Finishing agents are chemicals used to improve the appearance, feel, shrinkage, stabilize shape, extend service life, waterproof, fireproof, antifouling, anti-mildew, etc. of fabrics. Resin finishing agent is the most important finishing agent. It is a polymer compound that can bond with the hydroxyl groups of cellulose to achieve a more durable anti-wrinkle and non-iron effect. When mixed with appropriate softeners, it can improve fabric feel. Commonly used resins include urea-formaldehyde resin, melamine formaldehyde resin, dimethylol vinylidene urea resin, dimethylol dihydroxy vinyl urea resin and bishydroxyethyl sulfone. Among them, dimethylol dihydroxyethylene urea resin is the most commonly used and is formed by condensation of glyoxal, urea and formaldehyde. Penetrants, catalysts (commonly used metal salts, ammonium salts or organic amine salts) and feel adjusters should be added to the resin finishing working fluid. The latter is usually a softener. The newly developed resin finishing agent polyurethane is slightly more expensive, but has high styling performance, no residual formaldehyde, and does not cause skin allergies.
2. Softeners are mainly cationic long-chain fat-based finishing agents. Since cationic finishing agents have affinity for fibers, the dosage can be reduced, and they have strong adhesion and can display Long-lasting softness, its soft and lubricating properties mainly come from its long-chain fat base. Adding emulsified mineral oil and wax to this softener can increase lubricity. Some softeners react with hydroxyl or amine groups in the fiber to make the fiber more durable and have lasting softness. Recently, silicone oil dispersion softeners have appeared. Their ionic properties vary depending on the emulsifier used. After treatment, the fabric has a particularly soft and smooth feeling, which is suitable for high-speed sewing. If cross-linking silicon compounds are added, the elasticity of the fabric can also be enhanced.
3. Although the waterproofing agent rubber slurry coating can be waterproof, it has poor breathability when worn. Flashing grout is a mixture of aluminum salts and paraffin wax, but it is not durable. Breathable and durable waterproofing agents use long-chain aliphatic hydrocarbon compounds that react with fabrics.
Acrylic coating can also be waterproof after cross-linking. The newly developed waterproofing agent is hydrogen-containing silicone oil and its derivatives.
4. Temporary flame retardants include amine salts, sodium tungstate, borax, water glass, etc. Diammonium hydrogen phosphate and urea can be used to treat cotton cloth together. Certain durability. Organic matter is mainly compounds containing bromine, phosphorus, nitrogen, and chlorine, which can inhibit combustion. If it can be combined with fiber, it can have a long-lasting effect.
The main varieties of flame retardants for cotton have the following structure: There is still a lack of effective durable flame retardants for synthetic fibers. Three (2,3- Dibromopropyl phosphate is an effective flame retardant, but was banned in 1977 due to its toxicity. Currently, tetrahydroxyphosphorus chloride compounds, sulfides or hydroxyl compounds and resins are used, which have better durability. There are also flame retardants added before synthetic fiber spinning, but they have a certain impact on fiber performance and strength. Currently, new polybrominated compounds are being developed as flame retardants for synthetic fibers.
5. Antistatic agents, i.e. antistatic agents, are mainly used for synthetic fibers, which can not only prevent the generation of static electricity, but also make the fabric easy to decontaminate. Mainly include polyacrylic acid, polyethylene glycol ester and polymer amphoteric compounds.
6. Anti-mildew additive Cotton fabrics are prone to mildew in the presence of microorganisms, especially in the presence of slurry and appropriate temperature and humidity conditions. The applied antifungal agents include various copper salts and organic phenol derivatives, such as copper pentachlorophenol, copper naphthenate, copper 8-hydroxyquinoline, dihydroxydichlorodiphenylmethane, salicylanilide, etc. .
7. Anti-oil stain agents are mainly various derivatives of organic fluorine, which have extremely low surface energy, do not stick to oil, and are bonded to fibers with a resinous structure.
8. Coating agents are new finishing agents, including polyacrylate, polyurethane, etc., which give fabrics various additional properties, such as waterproofing, flame retardant, light-proofing, and elasticity. Gives inexpensive fabrics leather-like properties.
9. Functional finishing aids There are also many finishing aids that give fibers special functions, such as far-infrared warming and health-care finishing agents, anti-UV emulsion treatment agents, and antibacterial hygiene finishing agents. , ceramic powder far-infrared finishing agent, aromatic finishing agent, etc. </p
