What are the most commonly used additives in textile printing and dyeing?
Of course it is surfactant!
In the entire dyeing and finishing process, pre-treatment, printing and dyeing, and finishing are all indispensable for the presence of surfactants.
It is no exaggeration to say that surfactants can play a finishing touch and can often greatly improve the printing and dyeing process. and textile product performance.
Surfactant
1. Definition: Surfactant is A class of substances that can significantly reduce the surface tension or interfacial tension of water. Surfactant solutions have the functions of wetting, penetrating, emulsifying, dispersing, solubilizing, foaming and defoaming. In specific dyeing and finishing processes, they are used as detergents, leveling agents, penetrants, emulsifiers, softeners, and antistatic agents. agent.
2. Molecular structural characteristics: They all have positive adsorption and bulk characteristics in water dissolution.
Basic properties of surfactants
3. Application of surfactants in textile printing and dyeing
Different types of surfactants In the printing and dyeing process, each performs its own duties, each with its own advantages and disadvantages, which can be roughly summarized as follows:
1. Anionic surfactants for printing and dyeing processing
Anionic surfactants can generally be divided into four categories, namely carboxylate type, sulfonate type, sulfuric acid type Ester salt, phosphate ester salt.
Anionic surfactants have good dispersing, decontamination and solubilizing abilities and can be used as washing aids, scouring aids, penetrating agents, and wetting agents. Agents, emulsifiers, dispersants, etc.
Characteristics of anionic surfactants: Generally, they cannot be used in the same bath with cationic dyes and additives, otherwise insoluble substances may be produced; they have low affinity for cellulose fibers, but they are not compatible with cellulose fibers. Protein fiber has a greater affinity in acidic liquids; the stability of acids, alkalis and hard water varies with species; aqueous solutions of anionic surfactants are generally alkaline to neutral.
2. Cationic surfactants for printing and dyeing processing
Cationic surface Surfactants can be divided into ammonium salts, quaternary ammonium salts, and heterocyclic surfactants based on the position of the nitrogen atom in the molecule.
Cationic surfactants have poor detergency and are rarely used as cleaning agents. The reason is that the substrate surface of the object to be cleaned usually has a negative charge, while cationic surfactants have a positive charge. Charge, due to electrostatic attraction, makes the surface of the substrate hydrophobic and is not conducive to washing, and even has an anti-washing effect. However, this type of surfactant has good antistatic properties, softness, and good sterilization and disinfection capabilities. Therefore, cationic surfactants are mainly used as fabric softeners, acrylic dyeing leveling agents, antibacterial and antifungal agents, and color fixing agents. , antistatic agents, etc.
3. Amphoteric surfactants for printing and dyeing processing
Amphoteric surface Surfactants are the fastest growing class of surfactants in recent years and can be divided into two categories: betaine type and amino acid type.
Amphoteric surfactants have complex structures and high costs, but have low skin irritation, strong bactericidal power, strong foaming power, strong biodegradability, and are similar to anionic surfactants. Very good compatibility.
In printing and dyeing processing, amphoteric surfactants exhibit the following excellent properties:
Good stability to hard water and acid and alkali resistance It has good synergistic effect with various metal ions and other surfactants, and can be processed in the same bath with many dye additives;
It has excellent softness and antistatic effect , all types of fibers and fabrics feel soft to the touch and comfortable to wear after treatment;
It has good leveling properties and can be used as an excellent leveling agent when dyeing many fibers, especially wool fibers. ;
It has good decontamination foaming and emulsifying effects, and has buffering ability against acid and alkali. In addition to being used as fiber wetting and detergent, it also has a protective effect on fibers.
4. Nonionic surfactants for printing and dyeing processing
Non-ionic surfactants Ionic surfactants are divided into polyethylene glycol type and polyol type.
Nonionic surfactants exist in a molecular state in solution and have high stability; they are not easily affected by strong electrolytes and are acid and alkali resistant; they are compatible with other types of surfactants It has good solubility in water and organic solvents; it does not strongly adsorb on the solid surface.
It has defoaming, emulsifying, cleaning and dispersing effects. Among them, the main defoaming agents are fatty amides and polyoxyethylene dialkyl ethers; there are three series of emulsifiers: alkylphenol polyoxyethylene ethers (OP series), fatty acid sorbitan esters (S series), polyoxyethylene dialkyl ethers, Oxyethylene fatty acid sorbitan ester (T�� series); leveling agents such as Pingpingjia O, Pingpingjia O-15, etc. </p
