Development and Classification of Softeners

Dec 10, 2020

Softener is a kind of chemical substance which can change the static and dynamic friction coefficient of fiber. When the static friction coefficient is changed, the handle is smooth and easy to move on the fiber or fabric; when the dynamic friction coefficient is changed, the micro structure between fibers is easy to move, that is, the fiber or fabric is easy to deform. The combination of the two is softness. Softeners can be divided into cationic, nonionic, anionic and amphoteric quaternary ammonium salts according to their ionic properties.

Softener is a kind of chemical substance which can change the static and dynamic friction coefficient of fiber. When the static friction coefficient is changed, the handle is smooth and easy to move on the fiber or fabric; when the dynamic friction coefficient is changed, the micro structure between fibers is easy to move, that is, the fiber or fabric is easy to deform. The combination of the two is softness.

Soft finishing is an important finishing process in dyeing and finishing. In the process of textile processing, the handle will become rough after many times of treatment, and the general synthetic fiber fabric is worse, especially the ultra-fine fiber fabric. In order to make the fabric soft, smooth and comfortable, it is necessary to finish it. At present, softener is widely used. In addition, a large number of softeners are used in chemical fiber spinning, spinning and weaving of various fibers. This is because with the high-speed processing and the large use of small bath ratio in textile processing, the friction between fabrics and between fabrics and equipment increases, resulting in scratches and defects. The use of softener can make the fiber itself have the softness and smoothness suitable for the processing conditions to avoid damage. [1]

Cashmere softener is a kind of textile softener. It is specially used for the post-treatment of cashmere fabric to restore its natural softness. There are many kinds of cashmere softeners on the market, and the product quality is different. It has the following advantages:

(1) High shear stability;
(2) Stability in a wide range of pH values;
(3) The stability of electrolytes;
(4) It has good compatibility with cationic and anionic chemicals.

Development overview
Softener, as a conventional finishing agent for fabrics, has been developing very fast for more than half a century. It developed from the earliest surfactant softener to polymer polymer softener, and from polymer polyethylene wax to silicone polymer, and from polymethyl two silicone emulsion to hydroxyl terminated polysiloxane emulsion, hydrophilic silicone softener. Amino polysiloxane emulsion, amino polysiloxane microemulsion, low yellowing amino modified organosilicon softener, hydrophilic amino silicone softener and super smooth amino modified polysiloxane.

The earliest developed softeners are sulfate or sulfonate anionic surfactants. Due to their negative charge, they are very sensitive to hard water and electrolyte, and are not easy to be adsorbed by fibers, so they are not resistant to washing and dry cleaning. This kind of softener is seldom used in the softening finishing of cotton fabric alone. Paraffin and natural oils have been widely used in textile industry due to their excellent smoothness. As the fiber itself generally has negative charge, the softener made of cationic surfactant can be well adsorbed on the fiber surface, effectively reduce the static electricity of the fiber and the friction between the fibers, make the fiber stretch and not easy to bond into a group, so as to obtain the softening effect and give the fabric good antistatic property. Therefore, the softener made of cationic surfactant has made great progress. After the 1970s, with the development of organosilicon chemistry, silicone softener as a new type of polymer softener developed rapidly. Compared with the traditional non silicon softeners, the Si-O bond has a lower rotational free energy than the C-O bond, and the silicone softener shows better softness. Therefore, in the short decades since the emergence of silicone softener, it has been rapidly adopted by textile enterprises, and gradually replaced the traditional non silicon softener and became the dominant softener. [1]

classification
With the development of dyeing and finishing industry, all kinds of softeners have appeared one after another. In general, according to the chemical composition of softeners, they can be divided into 4 categories: non surface active, surfactant, reactive and polymer emulsion.
Non surface active class
In the early stage, non surfactant softeners were mainly mineral oil, paraffin and natural oil. The higher fatty alcohol, higher fatty acid and higher fatty acid ester have good softness and high-speed smoothness, which can also be used as raw materials of softener. Softener 101 belongs to this category.
Surfactants
Most softeners belong to this category. Among them, cationic softener is widely used in the finishing of cellulose fiber and synthetic fiber.
(1) Anionic softener
Anionic softeners were used earlier, usually sulfates or sulfonates. For example, sulfates of vegetable oils, sulfates or sulfates of fatty acids, succinate sulfonates, etc. Anionic softener has good wettability and thermal stability. It can be used with fluorescent whitening agent in the same bath. As softener of ultra white fabric, it has no color change on fabric. And nonionic compound used in bleaching fabric has a unique sense of smoothness. The representative variety is bis octadecyl succinate sulfonate, trade name softener ma-700. Due to the negative charge of the fiber in water, this kind of softener is not easy to be adsorbed by the fiber, resulting in weak softening effect and sensitive to electrolyte. It is usually used for cotton, viscose, cotton, etc