Ever wondered what makes sportswear so stretchy and elastic? Here is everything you need to know about elastane.
What is Elastane?
Elastane is also known as Lycra or Spandex. The word itself is an anagram and comes from the verb “expands”. The term ‘Spandex’ is used mostly in North America, however ‘Elastane’ and ‘Lycra’ are used more in Europe, UK, Australia and Middle East.
Elastane is a lightweight, synthetic fibre that is used to make stretchable clothing such as sportswear. It is made up of a long chain polymer called polyurethane.
Background of Elastane
As a synthetic polymer, Elastane is contains at least 85% polyurethane. The fibre can be stretched to some degree and comes back to its shape when released. Elastane fibers are strong, versatile and lighter than rubber which makes them superior. The chemical composition of Elastane makes it capable of stretching up to 600% of its original length.
Elastane fibres consist of many polymer strands, which are composed of two segments: long amorphous and short rigid segments. These segments’ features explain how the fibre stretches and recoils when released, and they together make the fibres soft. When fibres are forced to stretch, bonds between the rigid sections are broken. herefore, the amorphous sections straighten out and become longer. After reaching the maximum length, rigid sectors bond to each other, and amorphous sectors remain stretched. When a force is removed, the amorphous sectors recoil and the fibers become relaxed.
A brief history of Elastane
The production of Elastane started during WW2, since rubber-based fibres such as latex were not lightweight, durable and strong enough. Other than this, rubber was a highly important material during the war to build various equipment, and its price was fluctuating. DuPont scientist J. C. Shivers was motivated to replace rubber-based fibers. After almost a decade later, in 1959 he perfected the fiber, and it firstly called Fiber K, then DuPont decided to use the trade name ‘Lycra’.
Full-scale manufacturing started in 1962 by DuPont, and they are currently the world leader in elastane production.
The production process of Elastane
The production process passes through 3 phases and 6 steps. There are 4 different ways to produce the fiber, melt extrusion, reaction spinning, solution dry spinning, and solution wet spinning.
The process starts with the production of prepolymer through mixing macro-glycol with a diisocyanate monomer. A recommended ratio of macro-glycol to diisocyanate is 1:2.
During dry spinning, the prepolymer is then reacted with the same amount of diamine, and this forms achain extension reaction. The resulting solution is diluted with a solvent to produce the spinning solution and the solvent helps make the solution thinner and more easily handled. It can then be pumped into the fiber production cell.
Producing the fibres.
The spinning solution is pumped into a cylindrical spinning cell where it is cured and converted into fibres.
Through a compressed air device, the fibers exit the cell. Afterwards, a precise amount of the solid strands are bundled together to produce the essential thickness. Usually, the fibres of spandex consisted of many smaller fibres which stick to one another because of natural stickiness.
The fibres are treated with magnesium stearate or poly(dimethyl-siloxane). Then the fibers are transferred through a series of rollers onto a spool. The windup speed of the entire process can be anywhere from 300-500 mi (482.7-804.5 km) per minute depending on the thickness of the fibers.
When the spools are filled with fibre, the final package is set and shipped to textile manufacturers and other customers.
Characteristics of Elastane
Lightweight, supple, smooth and soft
In clothing, it prevents sagging and bagging
Stronger, more durable and higher retractive force than rubber
Resistant to deterioration by body oils, perspiration, lotions or detergents
Can be repeatedly stretched and recoils its very original shape very easily
Spandex can easily be dyed
What is Elastane mainly used for?
It can be used in a wide range of clothing types and accessories.
Athletics: swimwear, cycling suits, exercise wear.
Bodysuits: Zentai suits, leotards, wetsuits etc.
Accessories: belts, gloves, tights, socks.
Pants: skinny jeans, ski pants, shorts, yoga leggings.
and many more.
Elastane and the Environment
Currently, most of the clothes containing elastane are not recyclable once they have been worn out. According to the research in 2014, called “Removal of spandex from nylon/spandex blended fabrics by selective polymer degradation” and made by researchers Y. Yin, D. Yao, C. Wang and Y. Wang, fabric blends containing spandex are extremely difficult to recycle.
Therefore, elastane definitely contributes to environmental pollution and it contains toxic chemicals, since it consists of a similar chemical composition to polyester and plastic, which eventually end up in landfill sites. That means that elastane is a petroleum-based fiber, which requires a lot of energy to produce, and is not biodegradable. (You can check more detailed information about plastic and polyester on our blog)
Elastane also results in water pollution, as it contains microplastics which finally returns to the ocean, where it is washed away.
Is there a potential solution for the environmental problems Elastane causes?
Genomatica, a San Diego start-up company, has successfully converted natural sugars produced by microorganisms to an industrial plastic (BDO). It has the same properties as elastane,meaning it is stretchable, durable, strong and can effectively replace fossil fuel-based alternatives.
What can we do?
It is very difficult to imagine clothes without elastane and it is illogical to urge others to stop wearing clothes consisting of elastane. In 2010 alone it was estimated that 80% of garments bought by Americans contained elastane. But for the first step, we can use air drying instead of heat drying. Irrespective of the content of fabric, air drying is always the most environmentally-friendly option.
To discover more about other fabrics such as wool, nylon, viscose, denim and many more, check out our blog to read ‘The Fabric Series’.