Elastane
The manufacturing process of elastane is highly chemical and is derived from petroleum, a non-renewable resource. Elastane is non-biodegradable, and will impede the biodegradability of any natural fibre it is blended with. Efforts to address sustainability in these areas could help the overall positive influence of elastane on the environment. Elastane—also known as spandex—is the generic name for the synthetic, manufactured fibre whose fibre-forming substance is a long chain synthetic polymer. It comprises of at least 85% of segmented polyurethane. Some trade names for these fibres include LYCRA® (DuPont) and DORLOSTAN® (Bayer).[1] When used as the central filament core yarn with staple fibres such as cotton, elastane becomes the silent hero in the consumer use stage as it can prolong the life of a product by helping it retain its shape.
Contents
Benefits
Elastane was developed as an alternative to traditional natural fibres, since it can stretch and snap back to its original form, whereas natural fibres cannot. The environmental benefits of elastane occur in the consumer use phase. Elastane can be stretched repeatedly—up to 500% of its length—and will return back to its original size. It is lightweight, soft, smooth and does not restrict movement. It can be easily dyed and is resistant to abrasion, body oils and perspiration.
What makes elastane special is its compatibility with other fibres or yarns. Elastane fibres are included in textile applications where high elastic extension and recovery are needed for the material produced—such as stretch denim, activewear and underwear.[2] This allows for less stress on seams, and helps prevent garments from becoming loose-fitting in high stress areas such as the elbows or knees. This feature about elastane can assist with prolonging the life of the product and diverting waste from landfills.[3] When used as the central filament core yarn with staple fibres such as cotton, elastane becomes the silent hero in the consumer use stage as it can prolong the life of a product by helping it retain its shape.
Elastane can be machine washable and drip-dried, depending on the other fibres it is combined with, thereby minimizing water and energy use associated with consumer care and washing.
Potential impacts
Processing
All elastane fibres are segmented polyurethane and formed through spinnerets either by melt extrusion or by solvent spinning.[4] Polyurethane is a byproduct of petroleum, which is a non-renewable resource. Petroleum takes millions of years to form, and is currently being extracted from the earth for industrial uses faster than it can be replenished. The declining petroleum supply is the source of much debate—British Petroleum (BP) reports that there are 1,333 billion barrels still available to pump (enough for 40 years at current usage rates).[5] Other sources state that supply is overestimated and that reserves are about 30% lower than widely reported.[6] Many common solvents used for elastane production are toxic. Solvents such as dimethylformamide (DMF) are a potent liver toxin and research points to a possible association with cancer.[7] The production of elastane emits hazardous pollutants to air, which include: toluene and 2,4-toluene diisocyanate (TDI).[8] Toluene is found in gasoline, acrylic paints, varnishes, lacquers, paint thinners, adhesives, glues, rubber cement, airplane glue and shoe polish. Although not characterized as a carcinogen, chronic inhalation exposure to toluene and 2,4-toluene diisocyanate in workers has caused significant decreases in lung function, and an asthma-like reaction.[9] Toluene levels of 500 ppm are considered immediately dangerous to life and health.[10]
Dyeing and finishing
Certain types of dyes are suspected carcinogens and mutagens, while other dyes are known to have a sensitizing effect on skin and should be avoided. Untreated dye water can negatively impact receiving water bodies and harm aquatic ecosystems if left untreated before its release.
End of use
Elastane is used in a variety of different garments at different price points. It has durability to last the wearer several years; however, it is often used in inexpensive, fast-fashion garments that are worn and quickly discarded. Synthetic fibres are from a petroleum-based feedstock and are considered non-biodegradable.[11] Since elastane is often combined with biodegradable natural fibres, it can greatly influence the biodegradability of these fibres. For example, if even only 2% of elastane is combined with 98% cotton, it can cause the garment to be non-biodegradable.
Optimize sustainability benefits
OEKO-TEK certified elastane
OEKO-TEK is an independent, third party certifier that offers two certifications for textiles: OEKO-TEK 100 (for products) and OEKO-TEK 1000 (for production sites/factories). OEKO-TEK 100 label aims to ensure that products pose no risk to health. OEKO-TEK certified products do not contain allergenic dye-stuffs and dye-stuffs that form carcinogenic aryl-amines. The certification process includes thorough testing for a long list of chemicals. Specifically banned are: AZO dyes, carcinogenic and allergy-inducing dyes, pesticides, chlorinated phenols, extractable heavy metals, emissions of volatile components, and more.[12]
Bio-based elastane
Genomatica, a process technology developer for the chemical industry located in the United States, has developed a process that converts sugar (derived from sugar cane, beets or others) into commercial grade 1,4-butanediol (BDO), known as the GENO BDO™ process. BDO is a precursor to the chemical that makes elastane fibres. Bio-based BDO produced from the GENO BDO™ process is made from renewable feedstocks, rather than a conventional BDO made with petroleum-based feedstocks. Genomatica is currently licensing their process technology to producers and users in the chemical industry.[13]
Availability
OEKO-TEK® Standard 100 certified elastane is available. Manufacturers can be found at: www.OEKO-TEK.com/en/manufacturers/certified_products/certified_products.html Bio-based elastane is available by contacting Genomatica to be connected with suppliers that license the GENO BDO™ process.
Applications
Covered elastic yarn (covered with a spun or filament yarn to hide the elastane yarn): Heavyweight foundations, elastic bandages, althetic supporters.[3] Bare elastic yarn (monofilament elastane fibre): Swimwear, athletic wear, lightweight foundation garments.[3] Core spun yarns (central filament core with staple fibre): active sportswear, stretch denim, stretch chino.[3]
Marketing opportunities
OEKO-TEK® Standard 100 certified If verified and used.
XX% bio-based If verified and used.
Innovation opportunities
1. Investigate alternative technologies for colouring synthetic fabrics, such as transfer printing, which eliminates water from the dyeing process.[14]
2. Design garments and products with reusable elements—such as trims and tags. Design the product so that trims and tags can be easily separated from the main body of the product at the end of its useful life, to enable easy recycling. Create collection systems for the products. Collect, disassemble, reuse.
3. Work with partners to develop closed loop recycling of
elastane/natural fibres and infrastructure to label, collect, sort and purify garments.
Sources
- www.kpatents.com/pdf/applications/apn-4-05-03.pdf
- www.nepis.epa.gov
- Cohen, Allen and Ingrid Johnson. Fabric Science. New York: Fairchild Books, 2010.
- Corbman, Dr. Bernard P. Textiles: Fibre to Fabric. New York: McGraw Hill Book Company, 975.
- makewealthhistory.org/2010/06/11/how-much-oil-is-there-left-really/
- www.guardian.co.uk/environment/2010/jun/09/sir-david-king-dwindling-oil-supplies
- www.cdc.gov/niosh/docs/90-105/
- U.S Environmental Proection Agency, “Economic Impact Analysis for the Proposed Spandex Production NESHAP,” May 2000.
- www.epa.gov/ttn/atw/hlthef/toluene2.html
- emedicine.medscape.com/article/818939-overview
- Grose, Lynda and Kate Fletcher. Fashion & Sustainability: Design for Change. London: Laurence King Publishing Ltd, 2012.
- www.OEKO-TEK.com/media/downloads/Factsheet_OETS_100_EN.pdf
- www.genomatica.com/news/press-releases/far-eastern-new-century-showcases-apparel-with-high-renewable-content/
- www.triplepundit.com/2009/07/airdye-dyeing-fabric-without-water/
