Alternative to Spandex: Elastic Fiber

At present, spandex, as the crown of elastic fibers, has been widely used in hosiery, swimwear, inner pajamas, sportswear, fashion outerwear and health care products. Recently, the market trend of spandex market is still strong, and the supply of spandex market is tight. Although manufacturers maintain high levels and start operations, their inventory levels are still low, which still increases their prices. As of May 19, the average price of spandex 20D this week is 86,000 yuan/ton. , A month-on-month increase of 1.18%, an increase of 135.62% year-on-year. However, the production equipment and technology of spandex elastic fiber are complex, the raw materials and processing costs are high, the price is expensive, and there is "three wastes" pollution. At the same time, the fiber cannot be chlorine bleached during dyeing and finishing, the dyeing is difficult, the fiber is easy to melt during high-temperature finishing, and the fabric is stretched. Problems such as "whiteness" and "foaming", excess elasticity, and poor comfort will occur. In order to solve this series of problems of spandex fibers, in recent years, several types of elastic fibers with the characteristics of spandex have appeared on the market.

One is: two-component composite elastic fiber, a kind of PET composite elastic fiber and its preparation method. This method uses two kinds of PET chips with different viscosities, through the melted composite spinneret, after blowing cooling, oiling, winding, The nascent fiber is formed by traction, and the nascent fiber is then balanced, stretched, and shaped to obtain the finished filament. Because this method uses two kinds of PET with different viscosities as composite spinning raw materials, the resulting composite fiber has poor elasticity, the crimp elasticity is only 55-70%, and the breaking strength is low, less than 2cN/dtex.

The second is: a side-by-side composite elastic fiber and its manufacturing method. The method is to perform side-by-side composite spinning of polybutylene terephthalate and polyethylene terephthalate in a weight ratio of 70: 30. After silk, pre-oriented yarn (POY for short) is obtained, and POY yarn is false-twisted to obtain a side-by-side composite finished fiber (DTY for short), which has only low elasticity.

The third is: a new type of elastic fiber and its preparation method. The raw materials used in this method are PTT, PET, ECDP (atmospheric pressure cationic dyeable polyester) and PET with different viscosities. The process uses fully drawn yarn (FDY) Process, it not only needs to stretch the spun fibers and treat them in boiling water at 95-100°C for 15-20 minutes to prepare the finished composite elastic fibers, but the crimp degree of the fibers is only 43-55%, and the elasticity is seriously insufficient.

The fourth is: two-component polytrimethylene terephthalate (PTT) and composite elastic fiber represented by T400. Both of these fibers are made by composite spinning of polyethylene terephthalate (PET) and PTT. Among them, two-component PTT is a product developed by Shell, and T400 is an elastic fiber developed by INVISTA, which has the following characteristics.

(1) No need for false twist, excellent crimping performance, crimping shrinkage rate of more than 30%;

(2) It has excellent elasticity and can replace spandex in the field of medium and low elasticity. It is more elastic than PBT and PTT, and is more resistant to fatigue;

(3) Good dyeing performance overcomes the white space problem of spandex;

(4) Good anti-fatigue and anti-aging properties, and elasticity will not disappear with time;

(5) Good wrinkle resistance and easy care;

Because of these excellent properties, it can be widely used in the development of denim fabrics, giving denim excellent appearance, excellent elasticity and unprecedented wearing performance, and it can still maintain its original shape after repeated wearing. In woven fabrics, it gives the fabric a smoother texture and softer feel than textured yarns, and is used in all kinds of men's, women's and children's wear. With the continuous increase in the price of the substitutes and the excellent performance, the elastic fiber T400 may have a broader development space in the later period.