Current Status and Development of Fabric Softeners

Oct 28, 2021

I. Overview
After the fabric is pre-treated and a series of dyeing and finishing additions, the natural oil and wax are removed, which tends to reduce its original smoothness and make the hand feel rough. In addition, some fabrics need to undergo high temperature treatment, such as resin finishing, heat setting of synthetic fiber, steaming and puffing of acrylic fiber, and pigment printing, etc., which will also make the fabric feel rough and hard.

Most synthetic fabrics and pure wool and cotton velvet fabrics have problems such as hardening, rough hand feeling and uncomfortable wearing after washing or soap washing. In order to overcome this shortcoming, softeners are needed to improve them. With the development of synthetic fiber fabrics, people have increasingly urgent requirements for fabric softening, and the importance of softeners is particularly important.  give you a detailed explanation of the current status and development of fabric softeners.
(1) The mechanism of soft finishing
Soft finishing is a finishing that produces a soft touch by reducing the frictional resistance between fibers or between fibers and human skin. The frictional resistance between fabrics includes frictional resistance and dynamic frictional negative force. The former refers to the force that the fiber needs to overcome when the fiber is in contact with the fiber to make the fiber start to move, and the latter refers to the force that needs to be overcome to keep the fiber moving after it moves. force. Corresponding to static and dynamic friction, the related coefficients are called static friction coefficient (μs) and dynamic friction coefficient (μ a). In the soft finishing process, the static and dynamic friction coefficients are required to be reduced, and the static friction coefficient is reduced more.

Fiber is a substance with a large specific surface area composed of linear polymer materials. When the fabric fiber absorbs the softener, the interfacial tension of the fiber is reduced, and the fiber becomes easy to expand the surface and stretch the length. As a result, the fabric is fluffy, plump, and soft. Feel.
The role of softener
1. Supplement the natural oils lost by natural fibers in scouring and bleaching processes, making the hand feel more ideal.
2. Attach to natural fiber or synthetic fiber to improve smoothness and strength, and improve hand feeling.
3. Improve the wearability of the fabric through some characteristics of the softener.

In order to achieve the above effects, softeners are generally grease-like smoothness and hand-feel substances. Adhering to the fiber surface can reduce the frictional resistance between the fibers and make the fibers lubricate and soft. There are also some softeners that can cross-link with some reactive groups on the fiber to achieve the purpose of washing durability.

Requirements of softener
1. Under various soft processing conditions, the working fluid should be very stable.
2. Does not reduce the whiteness and color fastness of fibers or fabrics.
3. The softened fiber or fabric is not easy to be discolored by heat, and there should be no changes in color, feel, or odor during storage.
4. If the softener is emulsion, its emulsion stability is better
5. According to different processing requirements, it can have proper water absorption or water repellency, anti-static properties and other properties (should be selected according to the different requirements of the fabric). It is resistant to washing or dry cleaning.
6. There is no adverse effect after human skin contact.

Due to the wide variety of textiles, different fibers used, different fabric specifications, different fabric uses, and different finishing requirements, the selection of softeners cannot be generalized. On the basis of softening mechanisms and functions of various softeners, select those that meet the requirements. Softener. In addition, the performance of each softener is always limited. To obtain multiple performance effects, two or more softeners can be used in combination (or compounded into a new softener product). ). For example, the combined application of silicone softener and long-chain aliphatic softener can achieve better effects of soft, plump and slippery touch. It can also combine the application of softener with mechanical softening and often obtain good results. Effect.

Therefore, the long-chain aliphatic structure generally has a good softening effect. In the softening agent, there are not only many varieties, but also a relatively large amount. Such softeners can be divided into anionic, cationic, nonionic and amphoteric types according to their ionicity. In addition, natural oils and paraffin wax softeners, because they are natural lubricating substances, can also be regarded as a separate category, but they are also classified into different ionic categories according to the ionicity of the emulsifier used. . High molecular polymer softeners mainly include polyethylene and silicone. The variety of polyethylene softeners is relatively single, and the dosage is less, and the dosage is also less. The main thing that uses more is the silicone softener. Since the main chain of polysiloxane is a helical linear structure that is easy to bend, it can rotate freely in 360 degrees, and the energy required for rotation is almost zero. Therefore, the molecular structure of polysiloxane conforms to the softening mechanism of textiles. It can not only reduce the static and dynamic friction coefficients between the fibers, but also reduce the intermolecular force and reduce the surface tension of the fibers. It is a soft finishing agent for textiles. Ideal material. Silicone softener is the fastest growing softener variety in recent years.

Anionic softener
In addition to soap, sulfonated oil, etc., the anionic softener is mainly composed of cationic compounds or anionic and nonionic compounds with long chain alkanes such as stearyl succinate sodium sulfonate and stearyl ester sulfate. Generally, it has good wettability and thermal stability, can be used in the same bath with fluorescent whitening agent, and can be used as a softener for extra-white fabrics. It is also more suitable for cellulosic fibers, which can give fabrics better water absorption, but its adsorption to fibers is similar to that of direct dyes, which is relatively weak, so the softening effect is poor, and it is easy to be washed away. In addition, because it has a softening effect in the bath, it can be used for silk scouring to prevent scratches (grey scratches).

Non-ionic softener
Non-ionic softeners are generally polyoxyethylene esters (or ethers) of decaacid (or alcohol), fatty esters of pentaerythritol or sorbitol. Since non-ionic softeners have poorer absorption to fibers than ionic softeners, they can only play a smoothing effect. However, it can be used in combination with ionic softeners, has good compatibility with other materials, has good electrolyte stability, and does not have the disadvantage of yellowing the fabric. It can be used as a non-durable soft finishing agent, and can also be used as a synthetic fiber spinning oil. An important part of the agent. Some of its products can be used as silk-like finishing agents for fabric "Siming Yin".

Cationic softener
There are many kinds of softeners of this kind, and they are the most commonly used softeners at present.
Mainly because most fibers are negatively charged in water, cationic softeners are easily adsorbed on the surface of the fibers, have strong binding ability, can withstand high temperatures and washes, and the fabrics are plump and smooth after finishing, which can improve the wear resistance and wear resistance of the fabrics. It has a strong tearing force and has a certain antistatic effect on synthetic fibers. Therefore, it is widely used in cotton, nylon, acrylic and other fabrics, and this variety is also suitable for silk. However, some cationic softeners are prone to yellowing at high temperatures, accompanied by a decrease in light fastness. The cationic softener is generally a derivative of octadecylamine or dimethyloctadecylamine or a condensate of stearic acid and polyvinyl polyamine. According to its structure, it can be divided into tertiary amine softener, quaternary ammonium salt softener, imidazoline quaternary ammonium salt softener, dialkyl dimethyl quaternary ammonium salt softener and so on.

Amphoteric softener
Amphoteric softeners are a type of softener developed to improve cationic softeners. It has a strong affinity for synthetic fibers, and has no disadvantages such as yellowing and discoloration of dyes. It can also be used in the re-training process of silk to make the silk feel better. Amphoteric softeners can also be used together with cationic softeners to play a synergistic effect. Such softeners are generally of alkylamine lactone type structure.

Silicone softener
This type of softener is an emulsion or microemulsion of polysiloxane and its derivatives, which can make the fabric have a good soft and smooth feel. The products include emulsion polymerization, polymer silicone oil emulsification, modification, compounding and other production techniques, which have basically formed a system and supply more varieties and brands. But the application effect and performance are still very different.