Library of Textile, Apparel and Fashion

What is spandex: physical and chemical properties ||| Uses of spandex

Yashodhara Singh

National Institute of Fashion Technology India

Email: singhyashodhara21@gmail.com


A fast-paced consumer lifestyle demands comfort and shape in all phases of life. Increasing corporate workforce and gym-goers around the globe have led to a shift in garment manufacturing, which has trickled down the supply chain to textile production. The fashion industry has accommodated these changes with a focus on ease of movement and flexibility in garments. Notably, this need for stretchability is not limited to loungewear and athleisure but is making a mark in the workwear category as well; with Spandex being woven into our day-to-day lives. We are past the days when elasticity was just for women's wear. Numerous workwear brands have launched collections that break out of the rigidity of formal clothing and present a sleeker look made for motion at workplaces.

 

What is Spandex

Spandex is a fully 100% synthetic polymer fiber is known as Lycra and elastane.  Spandex is used to make high stretchable comfort clothing such as shapewear, sportswear, and etc. Initially, DuPont had developed spandex as an alternative to rubber, then spandex entered in Textile and clothing because of its high stretchability. Lycra and Spandex are the same fabrics best known as the fabric composition Polyether-polyurea copolymer. The fabric is best known for its high breathability property. The fabric is a lightweight fabric. Fabric is an elastomer, that can be stretched to a certain degree and recoils after being released. The chemical composition of the fabric is the reason for its elastic property. Spandex is the generic name for the polyether-polyurea copolymer, which as the composition reflects is a man-made fiber having the ability to stretch up to 5X (times). Its inception was inspired by the need for an alternative to rubber during the second world war.


Spandex vs Lycra; what is the difference

Readers often come across the term Lycra which is a trademark brand name of DuPont being used in place of spandex. It is because the company has been at the forefront of developing man-made textiles while being the leader of spandex production. At first, the American DuPont Textile Fiber company did the marketing of spandex. They used Lycra as their commercial name of Spandex in the clothing material market. DuPont set Lycra as the registered trademark name for the spandex. So the Lycra name started to become popular. Calling spandex lycra is not incorrect, as it is very popular all over the world. So spandex and lycra are the same things. The terms spandex, Lycra, and elastane are synonymous.


Spandex Fiber

Spandex fibers are produced by various methods which include melt extrusion, reaction spinning, solution dry spinning, and solution wet spinning. The initial step of reacting polymers to produce a prepolymer is common for all the above processes. The further step of converting the prepolymer to be drawn out into long fibers is different. The elastic nature of this fiber comes from its chemical composition. The fibers are made up of numerous polymer strands. These strands are composed of two types of parts:

●          Amorphous parts - longer and

●          Rigid parts - shorter

The long-amorphous parts intermingle and make the fibers soft. While the rigid parts bond with each other and provide structure to the fiber. Whenever this fiber is stretched- the bonds among rigid parts break down and the longer amorphous parts straighten out. Upon reaching their maximum stretching limit, the short rigid portions bond back together; while the amorphous portions remain in their elongated state. The amorphous parts recoil and the fiber returns to its relaxed state once the stretching force is removed. The spandex fiber is manufactured in filament form and is usually blended with other natural or man-made fibers to be spun into yarns or woven into fabrics. The spandex filament fiber can be spun into various types of yarns.

 

The Global Spandex Fiber Market is projected to reach more than 6 USD billion by the end of 2025, growing at a CAGR of more than 7% over the foreseeable future. Quotes Adroit Market Research in its report.


Physical properties of spandex

  1. Like polyester, spandex is extruded from spinnerets with circular orifices and hence usually has a circular cross-section.
  2. Elasticity: 500- 600 %
  3. Elastic Recovery: Very High, coming back to the same length. Able to be stretched repetitively and still recover original length
  4. Color: White or almost white color.
  5. Hardness: Very soft
  6. Lightweight
  7. Sunlight, sweat, or detergents effects: Never damage
  8. Prone to bubbling/ Piling: No
  9. Abrasion-resistant
  10. Moisture regains percentage lies between 0.8 & 1.2%.
  11. Spandex being a manmade fiber is produced in filament form and can be cut into staple fibers. It is usually found in a white/off-white shade.
  12. Low electrical conductivity.
  13. Breaking tenacity is 0.6 to 0.9grams/denier.


Chemical Properties of Spandex

Good resistance to most acids unless prolonged exposure. Good resistance to most alkalis. It resists dry cleaning solvents. It can be degraded by sodium hypo-chloride (bleach), while chlorine bleach should not be used. We do not find a fabric solely made from spandex; a garment with even 5% spandex would be highly elastic. Spandex is an expensive material but the slight percentage blended in everyday garments doesn't make the cost apparent.


Spandex Manufacturing Process

Spandex fabrics are very much useful in this era. As spandex is a fully synthetic fiber, so no natural fiber is used to make it. Spandex fabrics are made by a few chemical processes but those are complex processes. That is why spandex fabrics are very expensive compared to others but comfortable to wear. The high elasticity of spandex fabrics adjusts with human body shape. Here we are giving Spandex manufacturing process flow chart:

 

1.       Production of a Prepolymer: This step is accomplished by mixing macroglycol with a diisocyanate monomer with a special type of reaction vessel.

2.       Chain Extension Reaction: When the dry spinning method is used, this prepolymer is then reacted with diamine acid.

3.       Diluting: Next, this solution is diluted with a solvent to make it thinner and easier to handle.

4.       Extrusion: This cell spins to produce fibers and cure elastane material. Within this cell, the solution is pushed through a spinneret.

5.       Heating: These fibers are heated within nitrogen and solvent gas solution, to form the liquid polymer into solid stands.

6.       Twisting: The stands are then bundled together as they exit the cylindrical spinning cell with a compressed air device that twists them.

7.       Finishing: Next, magnesium stearate or another polymer is used to treat the elastane material as a finishing agent.

Weaving: The last stage of making fabric, once it is loaded onto a spool, it is ready to be woven into fabric.

Uses of Spandex
The use of spandex is evident in categories like athleisure and intimate wear, which consist of form-fitting garments like leggings, joggers, slim-fit types of denim, undergarments, and socks. It is hard to imagine a rigid sock that would not stretch while putting on/off. What doesn't meet the eye is the spandex filament spun with wool-polyester into a stretchable three-ply yarn for suiting fabric. Spandex typically used in below mentioned items.

Clothing/ Apparel: Denim, Skinny jeans, slacks, bra, underwear, socks, T-shirt, Gloves, swimsuits, aerobic/exercise wear, ski pants, golf jackets, disposable diaper, waistbands, bathing suits, belts, tights, and leggings.


Sportswear (Athletic wear): Tracksuits, shorts, bicycle pants, exercise wear, T-shirts, and polo shirts. Some other specialized garments of sportswear include fit dresses for any types of athletic, swimsuits (for use in swimming), wet suits (diving or surfing), ski suits (for skiing), and leotards (for gymnastics). Sports footwear includes trainers, ankle supports, football boots, riding boots, and ice skates. Sportswear also includes bikinis and some crop tops and undergarments, such as the jockstrap and sports bra. Nowadays, sportswear is also at times worn as casual fashion clothing.


Compression garments: Surgical hose, zentai suits, Wrestling Singlets, support hose, bicycle pants, Cycling shorts, bra cups, and jerseys.


Medical Products: Uses of Spandex in medical devices raised very high over the years, so Spandex is used in most medical products. Most of the orthopedic braces have the use of spandex fabric, those are used in hand, shoulder, leg, ankle and, etc.


Shapewear: Shapewear is also called foundation garments or shaping underwear. Foundation garments or shapewear women are women under clothing or undergarment whatever we call. This type of product has very high demand in Europe and USA. Shapewear is fully elastic, usually 20%  to 25% spandex use in shapewear products. The use of spandex does not vary too much compared to one and another product. Shapewear products fully get attached to the human body.


Reference: http://www.madehow.com/Volume-4/Spandex.html