In the printing and dyeing process, pay attention to the phenomenon of uneven dyeing or staining. Leveling agent means that the dyeing can delay the dyeing speed of the fiber (retarded dyeing), and can make the dye transfer from the high concentration of the fiber to the fiber. It is a kind of auxiliary agent for low-concentration parts (migrating dyeing) to avoid unevenness and staining, and does not reduce the fastness of dyeing.
This type of additives can increase the solubility of the dye, enhance its penetration and adhesion on the fiber, enhance its color and improve the washing durability of textiles.
1. These anionic surfactants such as sodium alkyl sulfonate and sodium sulfate of higher fatty alcohol can be used as fibrophilic leveling agents for natural fibers and nylon fibers.
2. Non-ionic surfactants such as higher fatty alcohol polyoxyethylene ether are mainly used for reduction dyeing, but also for dyeing with disperse dyes and direct dyes.
Detergents are widely used in the fiber spinning process, such as the desizing and scouring of cotton cloth, the degreasing and washing of wool, the degumming of raw silk, the degreasing of synthetic fibers, the removal of unfixed dyes after dyeing and printing, etc. All use detergent.
It has the properties of emulsifying, wetting, foaming, peptizing and suspending in water, thus showing significant decontamination ability, and is resistant to hard water. It will not precipitate when encountering calcium and magnesium ions, and does not produce free alkali in water. Will not damage the strength of silk and wool fabrics, not only can be used in alkaline or neutral solutions, but also in acidic solutions, the washing process is fast, the dosage is small, and it can be washed at low temperature.
Since cationic surfactants will produce electrostatic adsorption, the hydrophobic base of the surfactants will face the aqueous solution, and the dispersed dirt will easily stain the surface of the fabric. This is extremely unfavorable for fabric cleaning, so non-ionic, anionic and zwitterionic are generally used. The surfactants are used as detergents.
Dispersants are indispensable additives in dye processing and dye applications. Dispersants have two main special functions in dyeing: one is to disassemble the deflocculation of aggregated ions; the other is to maintain the stability of dispersed particles.
Some dispersants themselves have multiple functions such as dispersibility and migration, and can be used as a diffusing agent for dye processing and as a leveling agent in printing and dyeing. Among the currently used dispersants, anionic surfactants are the main ones, mainly naphthalenesulfonate-formaldehyde condensation and lignosulfonate, followed by non-ionic surfactants such as nonylphenol polyoxyethylene ether. It is often used in combination with other types of surfactants.
The above is the application of surfactants as textile auxiliaries in the textile industry. The role of textile auxiliaries is like the flavoring agent used in cooking. The purpose is to give textiles functional needs, such as softness and smoothness of the hand. Water-proof, stain-removing and anti-static properties are an indispensable part of the textile industry to make a finished fabric.