spandex，It's a kind of elastic fiber. Spandex is usually made up of long strands.

Physical and chemical properties

Synthetic fibers with high breaking elongation (400% +), low modulus and high elastic recovery rate. Spandex has high elongation (500% ~ 700%), low elastic modulus (200% elongation, 0.04 ~ 0.12g/denier) and high elastic recovery rate (200% elongation, 95% ~ 99%). In addition to the strength, other physical and mechanical properties and natural latex silk is very similar. It is more resistant to chemical degradation than latex silk, has moderate thermal stability, softening temperature of about 200℃ above. Most dyes and finishes used in synthetic and natural fibers are also suitable for dyeing and finishing spandex. Spandex is resistant to sweat, sea water and various dry washes and most sunscreens. Long-term exposure to sunlight or chlorine bleach can also cause color loss, but the degree of color loss varies greatly depending on the type of spandex.

Heat resistance varies greatly depending on the variety. Most fibers are stored in the range of 90 ~ 150℃ for a short time, and the fibers will not be damaged. The safe ironing temperature is below 150℃, which can be heated and wet washed. Dyeing performance is better, can be dyed into a variety of colors, dyes have strong affinity for fibers, can adapt to the vast majority of varieties of dyes, and has good chemical resistance, resistance to most acid and alkali, chemical agents, organic solvents, dry cleaning agents and bleach, as well as sun and snow resistance, but not resistant to oxides, easy to yellow fiber and strength reduction.

Use

Spandex is generally not used on its own, but is incorporated into fabric in small amounts. This fiber has both rubber properties and fiber properties, most used in spandex core-cored yarn, known as elastic core-cored yarn, the main characteristics of this yarn, one is to get good feel and appearance, natural fiber composed of outer fiber moisture absorption; Second, only 1-10% spandex filament can produce high quality elastic yarn; Three is the elastic percentage control range from 10% to 20%, according to the use of the product, choose different elastic values. It is easy to spin 25 ~ 2500 denier silk of different thickness, so it is widely used to make elastic woven fabrics, such as socks, furniture covers, ski clothes, sports clothes, medical fabrics, belts, quartermaster equipment, elastic parts of space suits, etc. Also useful spandex naked silk and spandex and other fibers combined twisting twisted yarn, mainly used in various warp knitting, weft knitting fabrics, woven fabrics and elastic fabrics.

Methods of production

1. Dry spinning: Solution in hot gas flow, due to solvent volatilization and curing into silk method.

Production process: solution - spinning pump - drying oven, 100 ℃ hot air blowing, volatile, spinning, winding molding solution.

Spinning speed: from 200 ~ 800M/ min.

Spinning temperature: 200 ~ 230℃.

Fiber size: 22.2 ~ 1244dtex.

Characteristics: The process pollution is large, the process is complex, the cost is high.

2. MELT SPINNING: melt-spinning, the method by which the polymer is heated above the melting point to become a melt and make silk.

Production process: polymer polymerization under solvent-free, granulation, biopsy under fixed temperature, removing impurity, drying, cleaning dehydration -- into screw mechanism into solution - spinneret extrusion - through cold box cooling - winding molding.

Spinning speed: 600 ~ 1600M/ min.

Spinning temperature: 160 ~ 220℃.

Fiber size: 9 ~ 1100dtex.

Features: Short process, low cost, little pollution.

3. Wet spinning

WET-SPINNING, a method in which the stock solution is solidified into silk by double diffusion in a coagulation bath.

Production process: concentrate - - from the spinneret spinning pump into the warm water, under 90 ℃ - - remove solvent regeneration trough coagulation bath - strips of washing, drying, winding molding.

Spinning speed: from 50 ~ 150M/ min.

Spinning temperature: warm water below 90℃.

Fiber size: 44 ~ 440dtex.

Characteristics: This method of production process pollution, slow spinning speed, high cost. [2]

4. Chemical reaction method

A method in which a solution made of a high polymer is solidified into silk by a chain extender which causes it to undergo chemical reaction.

Production process: solution - the spinneret to solidified liquid - add chain extender sclerosis of -- -- -- -- -- - winding forming processing into the reticular fibers.