Elastic fiber is an essential material in our lives. Without it, there would be no women’s stockings, no summer swimsuits, no figure-highlighting tights… It can be said that elastic fiber has made an indelible contribution to human beings showing their figures and enjoying the comfort of dressing.
We often see it in the ingredient content of clothes The elastic fiber is “spandex”. Although the content is not high, it is very important. Here the editor will share with you a shopping tip:
When shopping online, check the ingredient label of the clothes. When you see the spandex, you can roughly know that the clothes have a slimming effect and can be worn slightly tight. For clothes without elastic fibers, you should generally choose looser ones and not too tight. It should fit snugly, otherwise it will hinder normal activities. Isn’t it useful?
However, if you think spandex Just spandex, that’s a big mistake. We textile people work tirelessly to develop new fibers and new technologies, striving to contribute more to the clothing industry of mankind. . . . (It seems like we are far away again~~ Come back quickly)
According to the definition given by the American Society for Testing and Materials ASTM: Elastic fiber filaments are stretched repeatedly to at least 2 times their original length at room temperature, and can quickly return to their original length after the tension is released. Fiber, the following 6 types of fibers can all be called elastic fibers.
Diene elastic fiber (rubber yarn)
Diene elastic fiber is commonly known as rubber yarn or elastic yarn, and its elongation rate is generally 100%~ between 300%. The main chemical component is vulcanized polyisoprene, which has good chemical and physical properties such as high temperature resistance, acid and alkali resistance, and wear resistance. It is widely used in knitting industries such as socks and ribbed cuffs.
Rubber wire is an elastic material used in the early days Fibers, since they are mainly made into coarse yarns, have a limited range of use in woven fabrics.
Polyurethane fiber (spandex)
Polyurethane elastic fiber refers to a fiber made of a block copolymer with polyurethane as the main component , our country is abbreviated as spandex. The original product name in the United States was Spandex, which was later renamed Lycra, Elastane in Europe, Neolon in Japan, and Dorlastan in Germany.
Its elasticity comes from its molecular structure A block copolymer network structure composed of “soft” and “hard” segments. This kind of fiber has different block copolymers and different spinning processes. After forming different “segment” network structures, the elasticity and dyeing and finishing processing properties are also different.
Polyetherester elastic fiber
Polyetherester elastic fiber is an elastic fiber made from polyester and polyether copolymer by melt spinning, Japan Teijin Corporation in
First produced in 1990. Polyetherester elastic fiber not only has high strength, but also has good elasticity.
At 50%, the elasticity of medium-strength elastic fiber is equivalent to spandex, and the melting point is also higher. When blended with PET fiber, it can be used at 120℃~130℃
It is dyed at ℃, so polyester fiber can also be processed into elastic textiles. In addition, they have excellent light resistance, chlorine bleaching resistance, acid and alkali resistance, etc. are better than ordinary spandex. Due to its good acid and alkali resistance, the fabric composed of it and polyester can also be processed with alkali reduction to improve the drape of the fabric.
This fiber also has the advantages of cheap raw materials, With the advantages of easy production and processing, it is a promising fiber.
Polyolefin elastane
Polyolefin elastic fiber is produced from polyolefin thermoplastic elastomer through melt spinning. Dow Chemical (DOW
XLA, launched by Chemical in 2002, is the first commercialized polyolefin elastic fiber. It is produced by melt spinning of ethylene-octene copolymer (POE) catalyzed by metallocene catalyst in situ polymerization. It has good elasticity, 500% elongation at break, can withstand high temperatures of 220°C, is resistant to chlorine bleaching and strong acid and alkali treatment, and has strong resistance to ultraviolet degradation. Its production process is relatively simple, its raw material price is lower than that of spandex, and it produces almost no pollution during the production process and is easy to recycle.
Because polyolefin elastic fiber has a variety of Excellent performance, its application has become increasingly widespread in recent years.
Composite elastic fiber
CONTEX
Kantex (ST 100 composite elastic fiber, collectively known as T400 in the market
Elastic fiber) is a new two-component composite elastic fiber made of DuPont Sorona as the main raw material and ordinary PET through advanced composite spinning technology; it has natural permanent spiral curl and excellent bulking, elasticity and elastic recovery rate , color fastness and particularly soft feel. It can be woven alone or interwoven with cotton, viscose, polyester, nylon, etc. to form a variety of styles.
It not only solves the problem of traditional spandex yarn There are many problems such as dyeing, excess elasticity, complicated weaving, unstable fabric size, and easy aging during use. It can be woven directly on air-jet, water-jet, and arrow looms. It does not need to be made into covered yarn first like spandex. Only then can it be woven on the machine, which reduces the cost of yarn and improves the quality uniformity of the product.
Hard elastic fiber
The above-mentioned elastic fibers are all soft elastic fibers, which undergo large deformation and recovery under low stress. From a thermodynamic perspective, elasticity comes from the degree of freedom (or disorder) of the molecular chain, that is, the change in the entropy value of the system. Therefore, the crystallinity of the above-mentioned fibers is very low. However, some fibers made under special processing conditions, such as polypropylene (PP), polyethylene (PE) and other fibers, although not easy to deform under low stress (because they have a higher modulus), are not easily deformed under high stress. It also has good elasticity under stress, especially at lower temperatures, so this type of fiber is called hard elastic fiber.
The deformation and deformation of hard elastic fibers The recovery is significantly different from elastic fiber. For example, hard elasticity
PP
If the fiber is stretched a second time immediately after being stretched and recovered, its modulus and strength will drop a lot. However, if the fiber is left for a period of time after the stress is removed, or the temperature is raised to fully relax it and then stretched a second time, its modulus and strength will drop a lot. 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 retracting deformation of the long chain segments of the crimped molecules of the soft elastic fiber occur, but also some changes in the micropore structure are accompanied during the stretching process. The chip network structure has also changed. Only after these structural changes gradually recover can they return to their original state. Therefore, they deform and recover under higher pressure and are called hard elastic fibers.
At present, hard elastic fibers are used in textiles There are not many applications, but because its elastic characteristics are different from soft elastic fibers, some special textiles can be developed.
