Elastane, why is it so good?



Elastic fiber has entered every aspect of people’s daily life and is an essential textile and clothing raw material in life! Without it, there would be no stockings for beauty-loving women; without it, th…

Elastic fiber has entered every aspect of people’s daily life and is an essential textile and clothing raw material in life! Without it, there would be no stockings for beauty-loving women; without it, there would be no colorful and different swimsuits in summer; without it, there would be no tights that highlight the devil’s figure… It can be said that elastic fiber allows humans to show their figures and enjoy dressing. Comfort has made an indelible contribution!

01 Elastic fiber concept

From a textile perspective, the elasticity of elastic fiber and its special Depending on the molecular structure, its elongation can reach several times, and it can recover quickly after stretching. Usually elastic fibers refer to synthetic fibers with high elongation at break, nearly 100% elastic recovery capability, and very low initial modulus.

The earlier national standard GB/T 4146-1984 “Chemical Fiber Part of Textile Terminology” defined elastic fiber as: a synthetic fiber with high extensibility and high resilience. When this fiber is stretched to three times its original length and then relaxed, it can quickly return to its original length.

This definition clearly stipulates that the stretch ratio of elastic fibers is three times the original length. The current national standard GB/T 4146.1-2009 “Textiles Chemical Fibers Part 1: Generic Names” does not give a specific definition of elastic fibers, but gives the main characteristics of polyurethane elastic fibers and polyolefin elastic fibers. Out of description.

The American Society for Testing and Materials (ASTM) defines an elastomer as a material that can be stretched repeatedly to at least 2 times its original length at room temperature and can quickly return to its original length after the external force is released. Material. This definition is broader and refers specifically to elastic fibers.

ISO 2076:2013(E): “Textiles-Man-made fibers-Generic names” also does not give a definition of elastic fibers, but describes the properties of different elastic fibers.

△Description of elastic fiber characteristics by different standards

02 Classification of elastic fibers

According to elastic mechanism Differences, elastic fibers can be divided into intrinsic elastic fibers inlaid with soft and hard segments, such as spandex, rubber yarn, thermoplastic polyester elastomer; and morphological elastic fibers, such as those obtained through subsequent mechanical processing or due to differences in their own shrinkage properties. Bi-component composite fiber with crimp structure.

According to the elasticity, it can be divided into high elastic yarn (elastic elongation 400% ~ 800%), medium elastic yarn (elastic elongation 150% ~ 390%), micro elastic yarn (elastic elongation 150% ~ 390%) Elongation 20% ~ 150%) and low elasticity yarn (elastic elongation less than 20%).

03 Common elastic fibers

There are many types of elastic fibers on the market, which can be generally divided into: spandex elastic fiber (PU), polyetherester Elastic fiber, polyolefin elastic fiber (represented by DOW Company’s XLA fiber), PTT fiber, two-component composite crimped fiber (PET/PTT represented by T400), hard elastic fiber, etc.

At present, the most commercially successful elastic fiber is spandex, which is widely used in various plants in the form of spandex core-spun yarn; polyolefin elastic fiber (XLA) is particularly suitable for use in plants because it does not require heat setting. Wool fabric; PET/PTT bicomponent fiber has attracted widespread attention because it can be used directly without coating, has excellent chemical stability, and has the irreplaceable advantages of the first two composite fibers.

Polyurethane fiber (spandex)

Spandex fiber belongs to the polyurethane structure and is the earliest developed and most widely used variety of elastic fibers with the most mature production technology. . With high elongation, low elastic modulus and high elastic recovery rate, the elongation rate of spandex can reach 400%~800%, and the recovery rate of 500% production is as high as 95%~99%. Spandex also has excellent chemical stability and thermal stability. Spandex has good acid and alkali resistance, sweat resistance, seawater resistance, dry cleaning resistance, and abrasion resistance. However, spandex needs to be coated before it can be used, and it has the disadvantages of being not resistant to chlorine bleaching and easy to relax.

Generally, as long as 2% to 10% of spandex is added, the underwear can be soft, close-fitting, comfortable and beautiful, and the sportswear can be soft and move freely. It is a good drape and protection for fashion and casual pants. form and fashion.

Polyetherester elastic fiber

Polyetherester elastic fiber is made of polyester and polyether Elastic fibers produced by melt spinning copolymers were first produced in 1990 by Teijin Corporation of Japan. Polyetherester elastic fiber has a similar structure to polyurethane elastic fiber and also has “segment” structural characteristics. The “soft” segment is mainly a polyether segment, which has good flexibility, a long chain, and is easy to stretch and deform; the “hard” segment is a polyester segment, which is relatively stiff, easy to crystallize, and has a short chain. It acts as a node when deformed by force, imparts elastic recovery properties, and determines the strength and heat resistance of the fiber.

Polyetherester elastic fiber is not only stronger but also stronger��, elasticity is also very good. When elongated to 50%, the elasticity of medium-strength elastic fiber is equivalent to spandex, and the melting point is also higher. It is blended with PET fiber and can be dyed at 120~130°C, so polyester fiber can also be dyed. 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, easy production and processing, and is a promising fiber.

Polyolefin elastane (XLA)

XLA fiber is launched by Dow Corporation of the United States Polyolefin fiber has an average crystallinity of 14%, an elongation at break of 500%, can generate recovery, can withstand high temperatures of 220°C, is resistant to erosion by chemical agents such as chlorine bleaching and strong acids and alkalis, and has a strong Anti-UV degradation properties. After being washed, bleached, dyed, coated and bonded, its inherent elasticity is basically not affected. At the same time, because XLA fiber fabrics require less force to stretch than most other elastic fabrics, their shrinkage is more natural and comfortable, making them suitable for infant clothing.

In addition, because the main component of XLA is recyclable polyolefin, it will not be suitable for spinning volatile organic compounds during the textile process, does not contain heavy metals, and will not hinder the recycling of clothing.

Composite elastic fiber (T400 fiber)

CONTEX (ST 100 composite elastic fiber, collectively known as T400 elastic fiber in the market) is a fiber made of DuPont Sorona As the main raw material, it is a new two-component composite elastic fiber made with ordinary PET through advanced composite spinning technology; it has natural permanent spiral curl and excellent bulk, elasticity, elastic recovery rate, color fastness and a particularly soft feel. , can be woven alone or interwoven with cotton, viscose, polyester, nylon, etc. to form a variety of styles.

It not only solves many problems such as traditional spandex yarn is not easy to dye, has excess elasticity, is complex in weaving, is unstable in fabric size, and is prone to aging during use, but it can also be used directly on air jets, water jets, and arrow shafts. Weaving on the loom does not have to be made into covered yarn before weaving on the machine like spandex, which reduces the cost of the yarn and improves the quality uniformity of the product.

Hard elastic fiber

The above-mentioned elastic fibers are all soft elastic fibers and can operate under relatively low stress. Larger deformation and recovery will occur next. 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 recovery of hard elastic fibers are significantly different from those of elastic fibers. For example, if the hard elastic PP fiber is stretched for a second time immediately after recovery, its modulus and strength will drop a lot. However, if the stress is removed and left for a period of time, or the temperature is raised to fully relax it, the fiber is stretched a second time. 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 retraction deformation of the long chain segment of the soft elastic fiber crimping molecule occurs, but also some microscopic deformation occurs during the stretching process. As the pore structure changes, their wafer network structure also changes. 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 not widely used in textiles, but because their elastic characteristics are different from soft elastic fibers, some special textiles can be developed.

04 Use of elastic fibers

Clothes containing elastic fibers fit the human body shape, show beautiful natural curves, and increase the beauty; but they do not affect the shape of the body. The activities of the human body create comfort and cater to the human body’s requirements for comfort. Therefore, people are increasingly applying elastic fibers to various fabrics, such as swimwear, ski suits, casual sweatshirts, underwear, tights, stockings, etc.

Among the many functional varieties, elastic fiber, as a “sunrise industry”, can give the human body a good sense of contact and improve the wearing comfort of clothing. It plays an irreplaceable role in terms of fabrics, fluffiness and warmth, so it occupies a solid position in the textile industry in China and even the world. Giving textile fabrics a certain degree of elasticity has become an inevitable development trend in wearable textiles. </p

This article is from the Internet, does not represent Composite Fabric,bonded Fabric,Lamination Fabric position, reproduced please specify the source.https://www.tradetextile.com/archives/27168

Author: clsrich

 
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