Introduction to Textile Chemicals

It mainly includes three categories

1. Textile additives: spinning oil agents, antistatic agents, textile wax agents, polishing agents, mercerizing agents, bleaching agents, etc

2. Printing and dyeing aids: emulsifiers, scouring aids, penetrating agents, wetting agents, leveling agents, dispersants, detergents, reducing agents, fixing agents, pigment printing agents, fluorescent brighteners

3. Fabric finishing agents: resin finishing agents, softeners, hardeners, waterproofing agents, flame retardants, oil resistant agents, anti static agents, anti fouling agents, anti moth agents, anti mold agents, antibacterial and deodorant agents, water absorbents, reducing agents, deepening agents, fragrances, etc

Development direction of textile chemistry

Low foaming, strong penetration, high cleansing, and less polluting scouring agents

High lubrication, low foaming, anti-static, high emulsification emulsifier

Low foam, high temperature resistant, wrinkle resistant leveling agent to adapt to small bath ratios and fast dyeing at high temperatures

Low cost, high quality, formaldehyde free resin finishing agent

Multifunctional fixing agents for direct dyes, reactive dyes, and acidic dyes

Efficient leveling agent for cationic dyes

A pigment printing adhesive with low conjunctival temperature, softness, firmness, non yellowing, and non adhesion

A waterproof and soft agent that is resistant to water, moisture, oil, and dirt, and has good fastness

A flame retardant finishing agent with good flame retardancy, low toxicity, and low cost

Multifunctional or special functional finishing agents, such as water resistant, oil resistant, stain resistant, antibacterial, and odor resistant

Functions and Technical Progress of Main Textiles

1. Fiber oil agent

Mainly used to reduce friction, commonly used include natural mineral oil, vegetable oil, animal oil, synthetic esters (pentaerythritol esters, sorbitol esters, fatty alcohol esters, etc.), ethers (block or random polyethers composed of deoxyethane, deoxypropane, deoxybutane, etc.)

Synthetic fatty esters have low viscosity, low boiling point, high melting point, high wear, poor oxidation stability, and high temperature sensitivity of viscosity, so they are less commonly used. Polybasic fatty alcohol esters have lower volatility and freezing point, lower temperature sensitivity of viscosity, excellent thermal stability and wear resistance, good solubility and compatibility with licking agents, easy mixing with other oil agents, low metal abrasion, stable hydrolysis, and non-toxic. Polyol fatty acid esters have good thermal stability and antioxidant properties, so they are often used as smoothing components in oil additives

Polyether based synthetic lubricants have higher smoothness, membrane strength, and clustering properties than lipids, and have advantages such as antistatic properties, softness, and moisture absorption. However, their heat resistance is slightly worse than esters. Therefore, the direction of technological progress will be to develop polyether esters, dialkyl polyethers, phosphorus containing polyethers, and easily degradable polyethers

2. Antistatic agents

Static electricity can disperse the tow and produce filaments and broken ends, making it difficult to coil. By utilizing the ionic properties and hygroscopicity of antistatic agents, static electricity accumulation can be effectively prevented. At the same time, the adsorption and coordination properties of antistatic agents also help eliminate static electricity

Although various surfactants have antistatic agents, quaternary ammonium salts are corrosive, and amino acid based amphoteric antistatic agents are too expensive. Therefore, currently commonly used are alkanol phosphate esters, alkanol polyether phosphate esters, polyether fatty acid esters, alkylphenol polyethers, etc. However, in the compounding of oil agents, antistatic agents must meet the compatibility requirements of smoothing agents, while lauryl alcohol phosphophenol ester has excellent balance, so it is still widely used until now. In addition, polyethylene glycol ether phosphate ester, due to controlling its molecular weight, can change its hydrophilicity and lipophilicity, easily achieving emulsification and dispersion purposes, will be widely used in the future

3. Emulsifiers

The finish is added to the fiber surface in the form of lotion, and at the same time, it is easy to absorb after spinning, so the emulsifier is the key. Easy to meet the HLB requirements of different smoothing agents and antistatic agents, especially alkanol polyethers, alkylphenol polyethers, sorbitol fatty acid ester polyethers, polyethylene glycol fatty acid esters, etc. are widely used. The combination of dual or multiple emulsifiers can achieve better emulsification effect. In addition, the development of functional polyethers with a smooth, antistatic, and emulsifying structure has become a development trend

4. Cluster Agent

Bundling agents are used to improve the adhesion between fibers. They require high viscosity and good permeability, and their characteristics are opposite to those of smoothing agents. Therefore, when compounding oil agents, it is required to achieve a comprehensive balance between smoothness and bundling. The current cluster agents used include castor oil sulfate, castor oil polyether, fatty acid triethanolamide, etc

5. Fungicides and fungicides

In order to prevent foam, defoamer is generally added, and the effect of compounding is better. The dosage of cationic softener should not be excessive. To improve heat resistance, add a small amount of antioxidants (such as bisphenol A polyether). In order to prevent metal corrosion, rust inhibitors (such as alkanol phosphate esters) are added

2、 Warp Sizing and Desizing Agents 

Starch sizing has a long history, but there are many drawbacks. Currently, most of them have been converted to wild plants or their derivatives such as acorn starch, cassava starch, sophora bean powder, sodium alginate, etc. In addition, synthetic sizing agents such as PVA, PAC, CMC, as well as polyester (PET) and polyoxyethylene ether (PEO) are also being used

Although PVA is commonly used, when vinyl acetate (VAC) is copolymerized with acrylamide to modify PVA, it retains the excellent film-forming properties, adhesion, appropriate moisture absorption and softness of the original PVA, and also increases water solubility for easy desizing, making it more suitable as a synthetic fiber sizing agent. Recently, in the above copolymerization reactions, acrylic acid or special quaternary ammonium salts have been added to form a multicomponent copolymer, becoming a functional characteristic slurry. In addition, VAC can also be copolymerized and modified with butyric acid or acrylic acid, resulting in a fast sizing speed, smooth surface, and easy desizing synthetic fiber specific slurry

PAC is often used in the form of ammonium polyacrylate, which has stronger adhesion than PVA, smooth warp surface, and fast sizing speed, making it widely used. The typical weight components of PAC sizing agents are: acrylic acid (or methacrylic acid) 35-85%, acrylic acid (or methacrylic acid) 20-30%, and acrylonitrile (or methacrylonitrile) 15-30%

At present, the new generation of synthetic sizing agents is a water-based polyester compound composed of monomers such as benzoic acid, diols, and polyethers. It has excellent adhesion to polyester, and the amount of sizing used is significantly lower than other sizes. There is also no stickiness, and it is easy to wash off before dyeing. Its performance is superior to others. Adjusting the composition of co polyester can be applied to different processing of polyester and polypropylene fibers with different sizes. In addition, this type of copolyester can also be used as a coating finish for synthetic fibers, as discussed later

The desizing of starch sizing agents currently uses highly active&alpha& Flash; The tendency of amylase as a desizing agent is due to its low cost of use, but it also brings high activity&alpha& Flash; The problem of poor thermal stability of amylase during operation can generally be avoided by adding trace chelating dispersants and metal halides. Starch and PVA sizing agents can also use hydrogen peroxide, ammonium persulfate, sodium bromate, etc. for efficient oxidation desizing, but the use of oxidants poses new requirements for equipment materials. Various synthetic sizing agents commonly use non ionic surfactants such as alkylphenol polyoxyethylene ether as desizing agents. Although anionic surfactants are also available and cheap, their desizing effect is not as good as that of non ionic surfactants

A. Refining agents

The main chemical functions in scouring agents are as follows:

Caustic soda: neutralize acidic substances, saponify fats, dissolve silicates, and undergo fiber mercerization treatment

Sodium silicate: destroys lignin spots

Solvent: Dissolves fats and oils, promotes emulsification and cleansing

Salts: improve the cleaning effect

Chelating agent: Eliminates stains after chelating with heavy metal ions

Surfactants: increase permeability, remove oil stains, emulsify oils and waxes

Use of conventional surfactants

● Sodium alkyl sulfate: foreign name Mersolate (IG), domestic 601 detergent. Commonly used as a scouring agent to replace soap and Taikoo oil, in collaboration with alkaline agents, as a scouring agent for cotton fabric, and as a cleaning and bleaching agent for dyeing or printing

● ABS: Cotton scouring aids and detergents, also used as detergents for wool and silk fabrics

● Sodium oleate amide methyl taurine: 209 or pancreatic bleaching T, used for washing wool and silk, and a small amount used as a pre-treatment agent and leveling agent for cotton fabric

● Sodium oleate ethyl xanthate: pancreatic bleaching A, used for wool washing, dyeing and post-treatment of cotton and viscose

● Fatty alcohol sodium sulfate: Used for washing wool and silk fabrics, as well as for washing cotton and linen fabrics

● Sodium secondary alkyl sulfate: TEEPOL, used in wetting agents, detergents, penetrating agents, and leveling agents

● Sodium oleate acyl amino xanthate: Remy A, used for scouring and washing wool and silk, evenly distributed

● Fatty amide group sodium p-anisole xanthate: LS, used for washing wool fabrics to make fibers soft, and also for cleaning cotton fabrics after printing, as a leveling agent for reducing dyes and acid dyes

● Fatty alcohol polyoxyethylene ether sodium sulfate: Rihua YS&flash; 500, it is used in combination with insurance powder to restore and clean pure polyester after dyeing and printing

● Fatty amine polyoxyethylene ether sodium sulfate: LIPOTOL SK (Rihua), suitable for washing silk and nylon fabrics after printing and dyeing

● Fatty alcohol polyoxyethylene ether: used for cleaning and pre-treatment of acrylic and high-grade wool fabrics

● Fatty amide polyoxyethylene ether: ETHOMEEN (ARMOUR) from abroad. Mainly used in dispersants, penetrants, wetting agents, and leveling agents

● Fatty acid polyethylene glycol ester: a scouring, dyeing penetration, and leveling agent for various fibers

● Alkylphenol polyoxyethylene ether, imported IGEPAL, is used for degreasing and scouring wool, as well as for washing cotton and viscose fibers.

● The block copolymers of polyether, polyoxyethylene and polyoxypropylene are collectively referred to as polyether detergents, which are called PLURONINES (WYANDTTE CHEM) in foreign countries. They are mainly used with other detergents to prepare high-efficient and low foam detergents, which have strong emulsifying power and good levelness, and are also suitable as components of synthetic fiber oil. Most of them use nonylphenol (or octylphenol) polyoxyethylene ether (6-10), followed by xanthol (or lauryl alcohol) polyoxyethylene ether (6-7). In actual refining, some anionic surfactants are often mixed with non ionic surfactants to reduce costs. Wool scouring has special characteristics, and using nonylphenol polyoxyethylene ether (9) is good. At present, countries still believe that it has excellent wettability and detergency, and the ideal anionic surfactant used as a scouring agent should be octanol (or lauryl alcohol) polyoxyethylene ether phosphate. If used as a scouring agent for heavy pollution cleaning, it should also be nonylphenol polyoxyethylene ether phosphate. In addition, sodium lauryl sulfate or alkanolyl polyoxyethylene ether with low foam, nonylphenol polyoxyethylene ether, block polyether phosphate composed of ethylene oxide and propylene oxide are used for refining and cleaning the dyeing process

B. Bleaching agents

Usually, calcium hypohalide, sodium hypohalide, sodium hypohalide, hydrogen peroxide, peroxyacetic acid, etc

● Hydrogen peroxide is suitable for cotton, wool, and synthetic fibers

● Sodium sulfite is suitable for cotton and chemical fibers. It was used as acrylic in the 1960s, but during bleaching, halogen dioxide escaped

● In recent years, acetic acid has become popular and has a higher oxidation ability than hydrogen peroxide, making it particularly suitable for nylon and silk. However, higher requirements have been placed on equipment materials.

The premature catalytic decomposition of hydrogen peroxide not only leads to the failure of bleaching active substances, but also promotes fiber damage, especially for natural fibers. In order to control the decomposition of hydrogen peroxide, in addition to controlling the pH value of the bleaching solution, a stabilizer needs to be added. Firstly, alkali earth metals such as calcium and magnesium have good stabilizing effects, but in practical production, the commonly used ones are highly dispersed insoluble bodies formed by water glass and calcium and magnesium ions, which have the characteristics of low cost and good effects. In order to generate precipitation on equipment and fabrics, which affects the whiteness and texture of the fabric, phosphate, borate, or citrate have been used in recent years to reduce the amount of water glass used. Secondly, chelating agents that can bind metal complexes with calcium and magnesium ions are commonly used as hydrogen peroxide stabilizers, such as the magnesium salt of EDTA (ethylenediaminetetraacetic acid), the complex of EDTA and phosphate esters, and the salt of EDTA and triethanolamine. In recent years, surfactants have also been used as stabilizers for hydrogen peroxide, such as fatty alcohol sulfates, alkylphenol polyoxyethylene ethers, fatty amide polyoxyethylene ethers, and amino acid condensates of fatty acids. They can also synergistically act as stabilizers with calcium and magnesium salts.

3. Dyeing aids

This category of chemicals can be divided into about 30 series: dyeing carrier, wetting agent, penetrant, leveling agent, dispersant, retarder, buffer, chelating agent, anti precipitation agent, antistatic agent, anti migration agent, anti friction agent, lubricant, softener, foaming agent, foam stabilizer, defoamer, adhesive, thickening agent, fixing agent, color developing agent, fading agent, absorbent, oxidant, reducing agent, acid, alkali, Solvents, color darkening agents, gas fading inhibitors, etc.

1. Dyeing carrier

Dyeing carriers are chemicals that enhance the dyeing ability of polyester. Although polyester dyeing currently tends to be high-temperature and high-pressure dyeing, dyeing carriers also play a role in color repair and leveling.

The main staining carriers include: o-phenylphenol, etc., Biphenyl oxide, methylnaphthalene, perhaloethylene, 1, 2, 4.

Trihalobenzene, butyl benzoate, phthalate, methyl salicylate, o-phenylphenol, etc., o-phenylphenol and biphenyl are very effective, and they are mutually compatible in practical use due to cost considerations.

2. Wetting agent, penetrating agent

The fabric is first wetted by a dyeing bath, and then penetrates into the relaxed interior. In fact, these two types of surfactants are the same. However, due to the influence of pH and redox agents during dyeing, the main types used in practice are: sodium isooctyl succinate xanthate, sodium dodecylbenzene xanthate, sodium lauryl sulfate, sodium alkylnaphthalene xanthate, sodium oleate butanol sulfate, and non ionic surfactants. Among them, due to the good permeability of sodium isooctyl succinate xanthate, sodium oleate butanol sulfate has less foaming ability and is widely used, Sodium octanol phosphate and sodium butanol polyoxyethylene ether phosphate, as well as polyoxyethylene and polyoxypropylene block polyether phosphate, have good wetting power and have been widely used in recent years. Non ionic surfactants can adjust the length of the polyoxyethylene ether chain to meet various process requirements, so their use has increased. They mainly include nonylphenol polyoxyethylene ether or octylphenol polyoxyethylene ether, alkanol polyoxyethylene ether, etc. The actual use is often a combination of several surfactants, or a combination of surfactants and certain textile chemicals. When oxygen bleaching, a composite of nonylphenol polyoxyethylene ether and sodium dodecyl diphenyl ether dixanthate is used. A complex of sodium octanol sulfate and ethylene glycol monobutyl ether is used for strong alkali mercerization treatment.

3. Leveling agents, retardants, dispersants

The dosage of leveling agents is generally 1-4% of the fiber, and the dosage decreases when the dyeing strength is increased. Commonly used leveling agents are: alkyl aryl xanthate, alkyl alcohol or alkyl amine polyoxyethylene ether or its sodium sulfate, trimethylbenzyl ammonium halide, alkyl dimethyl benzyl ammonium halide, etc.

The problem of even dyeing and slow dyeing of acrylic fibers is particularly prominent, as the anionic groups on the surface of acrylic fibers are easy to combine with cationic dyes, resulting in discoloration. The currently developed migration type cationic leveling agents include alkyl quaternary ammonium salts, alkyl aryl quaternary ammonium salts, alkyl or aryl pyrimidine salts, alkylamine halides, etc. They are equivalent to" Colorless cationic dyes;, Firstly, occupy the surface of acrylic fiber, and as the dyeing process progresses, the leveling agent is gradually replaced by dyes to achieve a leveling effect. This type of leveling agent can also be mixed with traditional dyeing retardants to solve various dyeing chromatography problems.

The performance and structure of this type of migrating quaternary ammonium salt are closely related. The best leveling effect is achieved by iodide, followed by bromide, and the worst is halide. Among alkyl quaternary ammonium iodides and alkyl aryl quaternary ammonium halides, C12 has the best effect. Currently represented are ASTRAGAL M (BAYER), KM (BASF), etc.

The levelness of nylon is due to its cationic charge in the acidic dyeing bath, and the affinity of acidic dyes for nylon is much higher than that of wool, making it easy to color and flower. When dyeing nylon, the order of covering dyeing properties of various dyes on colored patterns is:

Disperse dyes ≯ acidic dyes ≯ mordant dyes ≯ direct dyes ≯ acidic complex dyes ≯ neutral complex dyes ≯ reactive dyes

Firstly, the representative product of anionic leveling agents is fatty acid polyoxyethylene ether sodium sulfate, produced by Japanese pharmaceutical company MIGREGAL 2N. It has a higher affinity for nylon at low temperatures than acidic dyes. As the temperature increases, its affinity for nylon gradually decreases, which is replaced by acidic dyes. Therefore, it has the function of repairing and leveling nylon fabrics dyed with acidic dyes. Secondly, the representative product of amphoteric leveling agents is sodium aliphatic amine dipolyoxyethylene ether monosulfonate, which can bind with anionic dyes while still maintaining water solubility. Therefore, it has good leveling performance for acidic velvet dyes with larger molecules. It also has high transfer ability, which can flatten the initial dyeing rate of different types of acid dyes during color matching, so it can be used as a leveling agent for color matching between acid dyes and acid velvet dyes. Finally, there are some high polymers, such as polyoxyethylene pyrimidine and polyvinylpyrrolidone, whose leveling properties even exceed those of commonly used anionic leveling agents. In addition, if a mixed leveling agent is used during nylon dyeing, it has a synergistic effect.

Fast dyeing of polyester is a small bath ratio and short time dyeing process that is difficult to achieve even dyeing. Non ionic or anionic surfactants can be mixed in a certain proportion to solve the problem of even dyeing. In high-temperature dyeing with dispersed dyes with larger molecular weights, ring dyeing often occurs, which means that the dye only dyes on the surface of the fiber and does not penetrate the core. Generally, fatty alcohol polyoxyethylene is used as a leveling agent. There is also a leveling problem during polyester hot melt dyeing. Although non ionic surfactants have a certain leveling effect, the unevenness of dyeing cannot be corrected during continuous hot melt dyeing. Therefore, a block copolymer composed of sodium acrylate/acrylamide/methyl acrylate (molecular weight between 30000 and 50000), as an anti migration agent, will achieve good leveling effect

Dispersants promote the uniform dispersion and suspension of insoluble dye particles in the dye bath. In the past, lignin xanthate, naphthalene xanthate formaldehyde condensate, and polyoxyethylene alcohol were commonly used as the main agents. However, the polyoxyethylene ether and polycarboxylate salts (copolymers of maleic anhydride and ethylene, propylene, and isobutylene, obtained through hydrolysis) of alkyl phenol formaldehyde condensate have been found to have better dispersion performance and a trend to replace traditional dispersants.

At present, the dispersing ability of dispersants is sensitive to temperature, which brings trouble. For example, when disperse dyes are used for high-temperature dyeing of polyester, the decrease in dyeing coverage is the reason for the poor effect of the dispersant. To improve the dispersion ability, efforts should be made to use non ionic or anionic surfactants with polyaromatic ring structures. For example, varieties with excellent high-temperature dispersion performance include stilbene ortho phenylphenol polyoxyethylene ether, benzyl ortho phenylphenol polyoxyethylene ether, etc. In addition, in the high-temperature rapid dyeing of polyester, a new generation of composite dispersants has been developed, such as a mixture of polyarylphenol polyoxyethylene ether sodium sulfate and glycerol polyoxyethylene ether fatty acid ester, which has good dispersion, leveling, and foam inhibition effects. Representative products include LEVEGAL MSF (BAYER), DISPRR GS&flash; 1 (Mingcheng Chemical, Japan), etc

4. Color fixing agents

Fixing agents are usually cationic compounds that can combine with dye anions to form a lake and improve washing fastness. However, they are generally not resistant to soap washing and can also reduce the light fastness of the original dye. If two or more quaternary ammonium salt cationic groups are introduced into the fixing agent, such as polyethylpolyamine and melamine, and polyfunctional ammonium salt synthesized from dihalopropanol and triethanolamine, the fixing treatment not only improves the wet treatment fastness, but also has a small impact on the color and light fastness of the dye. Therefore, the new generation of fixing agents is moving in this direction

On the other hand, in the past, the development of color fixing agents focused on increasing molecular weight to reduce water solubility and improve the fastness of color lakes on fibers. In recent years, development has shifted to introducing reactive groups to make the color fixing agent bond with fibers, thereby greatly increasing the color fixing amount. For example, the product GLYTAC (obtained by reacting secondary amines with deoxyhalopropane and then quaternizing with alkyl halides) can be used for reactive dye fixation, saving 50% of the dye and achieving the same dyeing depth and good color fastness. In addition, the cross-linked dye named BASAZOL in BASF's product combines with the hydroxyl, amino, and yellow amide groups of the dye through the action of cross-linking agent P (the reactant of acrylonitrile and polyformaldehyde), and then adds to the hydroxyl groups on the fiber to achieve color fixation. Crosslinking agent P is also used for fixing reactive dyes. In 1982, SANDOZ, Switzerland, developed a multifunctional reactive color fixing agent. It is a composite of polyamino resin with two active groups (imino and hydroxymethylamide groups) and DMDHEU resin (2D resin). The polyamino resin introduces hydroxymethyl groups on some of the imino groups after condensation with diethyl polyamine and dicyandiamide. This multifunctional reactive fixing agent is suitable for one bath dyeing of polyester and cotton with disperse dyes and directly cross-linked dyes, and has excellent fixation effect on the soaping fastness of some dark reactive dyes.

5. Defoamer, foaming agent, foam stabilizer

The common characteristic of surfactants is that they are prone to foaming, so defoaming becomes a necessity. Defoamers can be temporary (defoamers) and persistent (foam suppressants). Alcohols, ethers, ketones, and ester compounds can all be used as defoamers without any foam suppression effect. Organic silicon is currently a good defoamer and foam suppressor, but the dosage should not be too large, otherwise stains and defects will occur. Especially when fabrics need to be treated with fluorocarbon compounds, organic silicon defoamers cannot be used. Although some polyethers can also defoaming, the effect is not as good as organic silicon. At present, the combination of defoamers is used to reduce the amount of silicone oil and improve the defoaming ability.

Foaming agent performance involves foaming ability, foam shape, foam stability and other factors. Currently, the best foaming agent is oleamide N&flash& Flash; Sodium methyl taurate and sodium fatty acid monoglyceride sulfate, while sodium lauryl sulfate is widely used in foam printing and dyeing. At present, it is also believed that the combination of multiple foaming agents can improve the foaming property and foam stability. Foaming agent and foam stabilizer complement each other. In the past, natural polymers were commonly used as foam stabilizers. In recent years, foam stabilizer N— Hydroxyethyl fatty amide, alkylamino N, N&flash; Sodium diacetate, sodium alkyl betaine xanthate, sodium polyacrylate, etc. are becoming increasingly important. At present, the international popular commodity dyeing auxiliaries are basically developing in the direction of low foam

6. Acid release agents

Although the process of dyeing polyester cotton blended fabrics in one bath is simplified, it requires the use of specialized dyes and additives. Disperse dyes require high-temperature dyeing, while reactive dyes are prone to hydrolysis due to their high temperature alkalinity. Therefore, there is a problem of temperature and pH coordination during fiber dyeing. It is required to find an acid releasing agent that gradually decomposes acidic substances as the temperature of the dyeing bath increases, and automatically adjusts the pH value of the dyeing bath to achieve simultaneous dyeing of two dyes from low to high temperatures

Many organic amides, organic halides, and organic esters will slowly decompose and release acidic substances when heated. Their initial decomposition temperature and final solution acidity are: 40 °C/PH5, 80 °C/PH3-4100 °C/PH ≥3, respectively. By utilizing this characteristic, different acid release agents are compounded based on the expected K/S value (color yield of the dyed sample) during the dyeing process of disperse dyes and reactive dyes in one bath one step (or one bath two step), thus meeting the synchronous dyeing speed. In addition, organic lipids with complex acid releasing agents will become the dyeing carrier for synthetic fibers below 100 °C, and slowly decompose into organic acids above 100 °C to become acid releasing agents

7. Anti migration agents

After pad dyeing, fabrics often experience color differences due to the migration of dyes during drying. The commonly used sodium alginate is only used as an anti migration agent in the one bath method of disperse dyes and reactive dyes, but it can reduce the fixation rate of some dyes by 30% and cause color fading. In coating pad dyeing, sodium alginate is prone to agglomeration in acidic conditions, while alkalinity can cause a decrease in dyeing fastness and serious roller sticking

In recent years, BASF has developed PRIMASOL AMK (a copolymer of acrylic acid and acrylamide, with a molecular weight of 400000 to 800000), which has good migration resistance and can eliminate positive and negative color differences caused by uneven air flow during drying. There is also no color fading phenomenon, and it can also increase the fixation rate by 10-15%. SUPERCLEAR100 from Daxiang, USA; N (acrylic copolymer with a molecular weight of 400000), suitable for pad dyeing of disperse and vat dyes, with good resistance to dye migration and an increase in dye fixation rate of 10-15%. After the use of anti migration agents, the washing fastness and friction fastness will be reduced by half a level. This is because there are water-soluble groups in the anti migration agent molecules. The solution is to hydroxymethylate the acylamine group with a small amount of formaldehyde before using the anti migration agent to improve its bonding ability with fibers or dyes

8. Chelating agent

Almost all dyes can improve their brightness after using chelating agents; The use of fluorescent whitening agents can improve whiteness; The use of bleach can improve the stability of the bleach and enhance the bleaching effect; Used in desizing and refining, it can reduce spots and defects on the fabric

At present, there are two major types of chelating agents: polyphosphates and amino carboxylic acids. From a development perspective, the amount and variety of amino carboxylic acid derivatives are rapidly increasing. Famous ones include nitroglycerin triacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), hydroxyethylenediamine triacetic acid (HEDTA), diethylenetriamine pentaacetic acid (DTPA), diethylenetriamine pentamethylenephosphate (DTPMP), and ethylene glycol&flash; Bis (β&flash; aminoethyl ether)&flash; N. N&prime& Flash; Tetraacetic acid (EGTA), etc. The chelating ability of these amino carboxylic acid chelating agents with metals also increases in the order listed above. The new chelating agents developed in recent years are carboxylic acid derivatives of organic phosphides and polyamides, which have greater chelating power

9. Reducing agents, discharge agents, anti dye agents

The most commonly used reducing agents in printing and dyeing production are sodium hydrosulfite (Na2S₂O₄) and sodium formaldehyde bisulfite (NaHSO₂.HCHO.2H₂O), as well as sodium acetaldehyde bisulfite (NaHSO₂.CH₃CHO) and zinc formaldehyde bisulfite (ZnSO₂. HCHO. 3H₂O or Zn (SO₂HCHO)₂). Recently, there has been widespread attention abroad to the new generation of reducing agents sodium borohydride (NaBH₄) and thiourea dioxide (NH₂) CSO₂H)

Sodium borohydride is a mixture of trimethyl borate and sodium hydroxide at 230 °C– It is obtained through reaction at 250 °C and has a decomposition temperature of 400 °C. It is stable in dry air and has better stability than sodium hydrosulfite in wet air. It has uniform reduction ability and good affinity for dyes, with a dosage of only 10-17% of sodium hydrosulfite. The chemical name of thiourea dioxide is formamidine yellow acid, which is obtained by reacting thiourea with hydrogen peroxide at 20 °C. It is safe, stable, and easy to degrade, with a dosage of 15-20% of sodium hydrosulfite. Non carcinogenic, it has become a substitute for insurance powder in foreign countries. In addition, Japan's Matsumoto product MARVELIN S&ndash& Flash; 1000 is a new type of reducing detergent (synthesized by N–– p-benzylstearic acid amide in alkaline contact with polyethylene glycol), which is a high-performance reducing detergent using its complex energy. For example, MARVELIN S&ndash& Flash; 800 is 25% insurance powder, 72% soda ash, MARVELIN S&ndash& Flash; 1000 3%, bringing convenience to storage

There are also some special reagents used in dyeing. The commonly used discharge agents for vat dye leucosome discharge dyeing are dimethylaniline benzyl halides, etc. In the uniform or patterned dyeing of blended and interwoven fabrics, naphthalene yellow acid derivatives are commonly used as anti dyeing agents, such as KATANOL SL (condensation of naphthalene yellow acid and benzyl halide) or ALBATEX WS (condensation of alkyl naphthalene yellow acid and benzoic acid) for direct dyeing of silk and wool; Nitrobenzene yellow acid and its derivatives are commonly used as anti dyeing agents in vat dye printing; Anti dyeing agents for reactive dyes are commonly used, such as aminoacetic acid or hydroxymethyl xanthate; The dye inhibitor of phthalocyanine brilliant blue is also a derivative of multi-ethyl polyamines

The selection of discharge agents and anti dyeing agents is related to the type of dye and the characteristics of the fabric. There is currently a trend that discharge agents and anti dye molecules can be utilized and promoted as new products after changing different substituent groups

10. Solvents and cosolvents

Hydrophilic hydroxyl compounds have special solubility in dyes, which will become a new way to improve permeability, levelness, and color supply in dyeing. At present, in addition to conventional compounds such as ethanol, ethylene glycol, propylene glycol, cyclohexanol, benzyl alcohol, phenol, etc., alcohol derivatives are often used under specific trade names, creating a mystery. In recent years, they have better performance and are actually mixtures of multiple solvents. For example, solvents such as CELLSOLVE (ethylene glycol monoether), CARBITOL (diethylene glycol monoether), FIBRIT D (glycerol monoether) used for vat dyes and soluble vat dyes; SOLUTION SALT SV (N, N-Dibenzylaniline sodium xanthate) as a cosolvent for reducing dyes; The solvent used for phthalocyanine brilliant blue IF3G is LYOGEN TG (thiodiethylene glycol), and ACETIN (monoglyceryl acetate) is used as a co solvent for phthalocyanine dye