All Categories

Home > BLOG > Is it yarn that makes a product stretchy or the type of stitch?

Is it yarn that makes a product stretchy or the type of stitch?

July 10,2023

Composite elastic fiber (T400 fiber)

CONTEX (ST 100 composite elastic fiber, collectively known as T400 elastic fiber in the market) is a new two-component composite elastic fiber made of DuPont Sorona as the main raw material and common PET through advanced composite spinning process. With natural permanent spiral curling and excellent bulk, elasticity, elastic recovery rate, color fastness and special soft feel, it can be pure woven alone, or interwoven with cotton, viscose fiber, polyester, nylon, etc., to form a variety of types of styles. It not only solves the traditional Spandex silk is not easy to dye, excess elasticity, complex weaving, fabric size instability, and easy aging in the process of use and many other problems, and can be woven directly on the jet, water jet, arrow loom, do not have to be made into a covered yarn before weaving like spandex, reducing the cost of yarn, improve the quality of the product uniformity.

Polyolefin elastic fiber (DOW XLA fiber)

Polyolefin elastic fibers are prepared from polyene thermoplastic elastomers by melt spinning. XLA, launched by DOW Chemical in 2002, is the first commercial polyolefin elastic fiber produced by melt spinning of in situ polymerized ethylene-octene copolymer (POE) catalyzed by a metallocene catalyst. It has good elasticity, 500% fracture elongation, resistance to 220℃ high temperature, chlorine bleaching and strong acid and alkali treatment, and has a strong resistance to ultraviolet degradation. Its production process is relatively simple, the raw material price is lower than spandex, and the production process almost does not produce pollution and is easy to recycle.

Polyolefin elastic fibers have been widely used in recent years because of their excellent properties.

Hard elastic fibers

The above elastic fibers are soft elastic fibers, which have large deformation and recovery under low stress. From a thermodynamic point of view, elasticity comes from the degree of freedom (or disorder) of the molecular chain, that is, the change in the entropy of the system, so the crystallinity of the above fibers is very low. However, some fibers made under special processing conditions, such as polypropylene (PP), polyethylene (PE) and other fibers, although they are not easy to deform under low stress (because they have a higher modulus), but under higher stress, especially at lower temperatures, they also have better elasticity, so these fibers are called hard elastic fibers.

The deformation and recovery of hard elastic fibers are obviously different from those of elastic fibers. For example, the hard elastic PP fiber is immediately stretched for a second time after stretching recovery, and its modulus and strength are reduced a lot, but if it is placed for a period of time after removing the stress, or if the temperature is raised to make it fully relaxed for a second stretch, the deformation recovery is basically close to the first curve. This is because when the hard elastic fiber is stretched and recovered, not only the stretching and shrinking deformation of the long chain segments of the above-mentioned soft elastic fiber cringing molecules occur, but also some changes in the micropore structure and the structure of their wafer network also change during the stretching process. Only after these structural changes gradually recover, can they return to the original state, so they deformation recovery under higher pressure, called hard elastic fibers.

At present, hard elastic fibers are not used much in textiles, but because their elastic characteristics are different from soft elastic fibers, some special textiles can be developed.

Hot categories