How many forms of spandex elastic fiber yarn are there?
Spandex elastic fiber is mixed with other fibers and spun into elastic yarn. There are currently three forms of yarn Form: spandex core-spun yarn, spandex twisted yarn and spandex covered yarn. The three forms of yarn are essentially different in processing principles and structural properties. Therefore, their uses and weaving properties also vary greatly. The structural diagram of the three types of yarns is shown in the figure.
What is the origin of spandex fiber and its main properties?
Spandex fiber is a type of elastic fiber. Elastic fiber is collectively called Spandex abroad. The product name in my country is spandex. In fact, spandex is only elastic fiber. A broad category. Spandex fiber (Polyurethane Fibre) is referred to as PU fiber. There are two varieties. One is a copolymer embedded with aromatic diisocyanate and polyester segments containing hydroxyl groups, which is referred to as polyester spandex. The other variety is made of aromatic diisocyanate and hydroxyl-containing polyester segments. Polyether segment-embedded copolymer of hydroxyl groups is referred to as polyether spandex. The representative trade name of polyester spandex is Vyrent, and the representative trade name of polyether spandex is Lyera.
The main properties of spandex fiber are: usually an elongation of 500% to more than 700%, and good elastic recovery performance. It retracts 97% at 200% elongation and over 99% at 50% elongation. The relative density of various spandex has a small difference, generally 1.20~1.25, and the breaking strength is 4.41~8.82cN/tex (0.5~1.0g/denier). The strength of polyester spandex is lower, while the strength of polyether spandex is higher. The moisture absorption rate is generally 0.3%-1.2%. The moisture absorption rate of multifilament is slightly higher than that of monofilament. The heat resistance is generally between 95 and 150°C. Short-term storage will not damage the fiber. The safe ironing temperature is below 150°C. Fiber burns slowly and forms a gelatinous residue after burning. It has excellent dyeing performance, can be dyed in a variety of colors, and has strong affinity for dyes. It has good acid and alkali resistance, can be bleached, and does not become moldy.
Why does denim spandex lose elasticity?
In denim fabrics, low-elastic and high-elastic spandex core-spun yarn materials are becoming more and more common, and the elasticity of spandex directly determines the progress of the denim washing process. In addition to its poor quality and easy loss of elasticity, spandex elastic yarn is also affected by many external factors.
1. Enzyme powder in the enzyme washing process
Because the enzyme powder It is a multi-component compound, and the differences in its internal chemical components will affect the elasticity loss of spandex, especially the anti-dye components. Adding nonionic 760 high-efficiency anti-dye paste can effectively prevent staining and color transfer. The most important thing is that the damage to elasticity is almost zero!
▲760 High Efficiency Anti-Dyeing Cream
2. Sodium hypochlorite (bleach)
Since spandex itself is not resistant to chlorine, the elasticity of the spandex is greatly damaged during the chlorine bleaching process, and the bleaching process Concentration, pH and other reaction speeds also play an important role in the elastic damage of spandex, and heavy bleaching causes greater damage.
The following are some suggestions for mitigating the elasticity loss of spandex:
1. Prep the denim garments that require chlorine bleaching. Use spandex chlorine bleaching anti-brittle agent SCL 1-3g/L (1/10 of the bleaching water) in the water bath for 1-2 minutes, gradually raise the temperature to 40°C, add the bleaching water three times, and add 1/5 of the total bleaching water for the first time. amount, add 2/5 of the total amount of bleaching water for the second time, add the remaining 2/5 of the bleaching water for the last time, and operate according to the actual bleaching time.
2. After bleaching, drain water while filling in water. The water temperature will gradually drop. The reason for this is to prevent the spandex from becoming brittle and elastic due to a sharp drop in temperature.
3. Softness
Since various additive manufacturers have , silicone oil and other formulas are different, some softeners and silicone oil can damage the elasticity of spandex, mainly because some of their components contain a small amount of solvent, which has an impact on the elasticity of spandex. Some silicone oils and softeners basically do not contain this solvent and have no effect on the elasticity of spandex.
Four. Solvent
Due to spandex The weaving process contains silicone-containing oils, which need to be removed during the dyeing and finishing process. Many scouring agents contain solvents, which have a great impact on the elasticity of spandex.
5. Physical cutting
Because the characteristic of cowboys is nostalgia , so many need to be physically damaged and cut. The damage exerts uneven force on the spandex elastic yarn, resulting in spandex blistering. The exposed yarn is also easy to break, leading to loss of elasticity.
6. Drying temperature
Generally, the drying temperature of denim fabrics containing spandex elastic yarn is lower than 60℃, so the temperature is too high It will cause great damage to the elasticity of spandex. </p
