Detailed explanation of the types and characteristics of various softeners(1)

In order to make the fabric have a soft, smooth or plump hand, in addition to mechanical finishing, most fabrics are finished with a softener. This article introduces the functions, requirements, types and their characteristics of softeners.

The role of softeners

1. Supplement the natural oils lost in the process of scouring and bleaching of natural fibers, making the hand feel more ideal.

2. Attached to natural fibers or synthetic fibers to improve smoothness and strength and improve hand feel.

3. Improve the wearing performance of the fabric through some characteristics of the softener.

In order to achieve the above functions, softeners are generally substances with the smoothness and hand-feel of oils and fats. Attaching to the surface of fibers can reduce the frictional resistance between fibers and make the fibers lubricious and soft. There are also some softeners that can cross-link with some reactive groups on the fibers to achieve the purpose of washing resistance.

2. Requirements for softeners

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 fibers or fabrics after soft treatment are not easy to be discolored by heat, and there should be no changes in color, feel and smell during storage.

4. If the softener is an emulsion, its emulsion stability is better.

5. According to different processing requirements, it can have appropriate water absorption or water repellency, antistatic properties and other properties (should be selected according to different requirements of the fabric). It is washable or drycleanable.

6. No adverse effects after contact with human skin.

Due to the wide variety of textiles, different fibers, different fabric specifications, different uses of the fabric, and different finishing requirements, the selection of softeners cannot be generalized. On the basis of the softening mechanism and function of various softeners, choose the one that meets the requirements. softener. In addition, the performance of each softener is always limited. To obtain the effect of multiple performances, two or more softeners can be used in combination (or combined into a new softener product). ). For example, the compound application of silicone softener and long-chain aliphatic softener can achieve better effects of softness, plumpness and smoothness. It is also possible to combine the application of softener with mechanical softening finishing, which can often achieve good results. Effect.

3. Types of softeners

Softener is a kind of auxiliaries with the largest variety and the largest amount in dyeing and finishing auxiliaries. According to reports, among the 920 samples of domestic and foreign auxiliaries collected by the Shanghai Institute of Printing and Dyeing Technology from 1990 to 1999, there were 350 softeners, accounting for 38%. So many types of softeners, according to their chemical structure, are basically two categories of long-chain aliphatic or high molecular polymers. The hydrocarbon long chain in the molecular structure of the long-chain aliphatic softener can be in a randomly arranged curling state, forming the flexibility of the molecule. Dynamic and static friction coefficients of fibers.

Therefore, the long-chain aliphatic structure generally has a good softening effect, and there are not only many varieties in softeners, but also a large amount. This type of softener can be divided into anionic, cationic, nonionic and amphoteric according to its ionicity. In addition, for natural oils and paraffin softeners, because they are all natural lubricating substances, they can also be regarded as a separate category, but they are also classified into different ionic categories according to the ionic properties of the emulsifiers used. . There are two main types of polymer softeners: polyethylene and silicone. The variety of polyethylene softeners is relatively simple, the dosage is also small, and the dosage is also small. The most used ones are mainly silicone softeners. Since the main chain of polysiloxane is a very flexible helical straight chain structure, it can rotate 360 degrees freely, and the energy required for rotation is almost zero. Therefore, the molecular structure of polysiloxane alone conforms to the softening mechanism of textiles, which can not only reduce the static and dynamic friction coefficients between fibers, but also have very small intermolecular forces and reduce the surface tension of fibers. ideal material. Silicone softener is the fastest growing softener variety in recent years.

4, the style characteristics of the samples

In addition to soap, sulfonated oil, etc., the main components of anionic softeners are cationic compounds or anionic and nonionic compounds with long-chain alkanes such as sodium stearyl succinate sulfonate and stearyl 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 cellulose fibers, which can give the fabric 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. Also, because of its in-bath softening effect, it can be used for silk scouring to prevent chafing (greying).

5. Nonionic softener

Nonionic softeners are generally polyoxyethylene esters (or ethers) of ten acids (or alcohols), fatty esters of pentaerythritol or sorbitan. Since non-ionic softeners have poorer adsorption to fibers than ionic softeners, they can only play a smoothing role. However, it can be used in combination with ionic softeners, has good compatibility with others, good stability to electrolytes, and does not have the disadvantage of yellowing fabrics. It can be used as a non-durable softening and finishing agent, and can also be used as synthetic fiber spinning oil important part of the drug. Some of its products can be used as a silk-like finishing agent for the "silk sound" of fabrics.