Polyester’s positive attributes for clothing lie mostly in the consumer use phase of its lifecycle, which accounts for 50-80% of a polyester garment’s total ecological footprint. Polyester garments are generally washed in cold water and drip-dried, thereby minimizing water and energy use associated with garment care.[4]
In comparison to other synthetic fibres, there is currently more research and innovation when it comes to sustainability and improving polyester’s environmental impact.
==Manufacturing ==
PET is made from ethylene glycol and terephthalic acid. From that polymer, fibers are made by a [[melt-spinning]] process, mostly in a continuous line with both the polymerization and melt spinning. The high speed at the [[spinning]] process requires the use of lubricants (spinning oils). They are commonly made of mineral oil with the addition of surfactants to facilitate the washing-out process when dyeing. In order to avoid that the fiber turns glassy (shiny) a matting agent in the form of titanium dioxide, or silicates are added, also optical brighteners are added. For the polymerization one needs small amounts of metal catalysts and at the end of polymerization one also needs a “catalyst-poison” in order to get the correct chain lengths.
== Potential impacts ==
Petroleum, the main ingredient in manufacturing polyester, is a non-renewable resource and mining for petroleum destroys natural habitats. That is to say that 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]
The manufacturing process for polyester is fully chemical, energy intensive and releases greenhouse gasses into the environment.[7]In the production of polyester, the main ingredients used are terephthalic acid (TA) or dimethyl terephthalate, which are reacted with ethylene glycol, based on bromide-controlled oxidation.[7 ] The production of polyester emits emissions to air and water, which include: heavy metal cobalt; manganese salts; sodium bromide; antimony oxide; and titanium dioxide.
Antimony is of particular concern, since it is a toxic heavy metal known to cause cancer under certain circumstances and is a suspected reproductive toxin.[7] The function of antimony in the production of polyester is as a catalyst in the oxidation process. But it is not absolutely necessary for polyester production, and alternate non-antimony catalysts are available.
Europe meets its oil consumption/needs by importing from foreign sources: 41% from the Russian Federation, 26% from Africa, 16% from the Middle East—14% comes from Europe—thus requiring transportation over long distances.[8][9] Fuel released by vehicles used to transport the oil causes pollution and CO2 emissions.
Discarded polyester products increase load on landfills, contribute to water contamination and possibly toxic emissions into the air.[11] According to a study done by Mark Browne, an ecologist at University College Dublin, microscopic fragments of polyester, acrylic, polyethylene, polypropylene, and polyamide have been discovered in increasing quantities across the northeast Atlantic, as well as on beaches in Britain, Singapore and India. A chemical analysis revealed that nearly 80% of the filaments contained polyester or acrylic.[12]
== Alternatives to virgin polyester ==
Teijin recently established a joint venture with one of China’s largest fibre producers, bringing the manufacture of chemically processed recycled polyester to China.[15]
{| class="wikitable"
• Diverts textile waste from landfills
|| • Difficult to label, collect, sort and purify post-consumer garments on a large scale
• Some fabrics with chemical backing, lamination, finish or those used in complex blends with other synthetics (nylon, for example) are not physically recyclable.[14]
• Recycled polyester from PET bottles is particularly suited for use in fabric such as polar fleece, where the construction of the fabric hides slight yarn variations.[14]
• This process degrades the fibre and eventually the product is disposed of in the landfill.
• Beware: The demand for used PET bottles is now surpassing supply in some areas and reports indicate that some suppliers are buying new bottles to make polyester textile fibre that can be called recycled.[14 ]
|| • Since the base colour of recycled polyester chips varies, colour inconsistencies in the fabric may occur, and this can lead to the need for re-dyeing. Re-dyeing greatly increases levels of water, energy and chemicals used.[14]
• Some fabrics with chemical backing, lamination, finish or those used in complex blends with other synthetics are not chemically recyclable.[14]
|| • Uses significant amounts of energy.
|}
== Alternatives to virgin polyester ==
=== Biopolymer fibers ===
==== Polylactide (PLA) ====
Polylactide (PLA) is a renewable thermoplastic and a polymer. It is derived from the starch of plants such as corn, sugar cane and sugar beet. PLA is biodegradable, as it decays as a result of exposure to heat and moisture. It decomposes forming carbon dioxide and water, which present no danger to the environment.[16][17]
=== Biopolymer fibres ====== Polylactide (PLA’s ability to biodegrade comes as a result of its hydrolysis and low melting point. These features could hinder PLA’s ability to be suitable in some applications, such as the outdoors or fabric that needs to be ironed. However, efforts to address these drawbacks in PLA) ===have recently been accomplished. NatureWorks LLC, which offers a brand name of PLA called Ingeo, has developed hydrolytic stabilizers that can be implemented in certain applications to prevent degradation outdoors. The company is currently working to increase the melting point of PLA so that it can be ironed.[18]
==Optimize sustainability benefits==
* Promote the use of recycled polyester that has been recycled using a chemical process.
* Promote the use of mechanically recycled polyesters from producers that use high quality raw materials.
* Promote the use of antimony-free polyester.
* Promote the use of polylactide (PLA).
* If using recycled polyester from PET bottles, ensure that the supplier is using recycled bottles, rather than new ones.[15]
* Promote the use of low-impact dye and bleaching processes.
* Promote the use of OEKO-TEK certified polyester.[19] 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.
==Availability==
Due in part to the volume of discarded soda bottles, mechanically recycled polyester is readily available to textile and apparel suppliers.
Companies such as Freudenberg Politex in Italy, and REPREVE® and Poole Company in the United States are producing versions of mechanically recycled polyester that are of almost equal quality to virgin polyester because of the high quality of raw materials used.
Chemically recycled polyester is gaining in popularity and the number of companies offering fabrics made from this technology is increasing globally. The Japanese company Teijin which first developed chemical recycling technology, recently established a joint venture to establish fabric manufacturing in China.
Eco Intelligent™, antimony-free polyester, is available through Victor Group in North America. Antimony free tititanium-based catalysts are available from Johnson Matthey's catalyst Vertec and Teijin's "heavy metal free" polyester chip.[20][21]
Polylactide (PLA) is still a developing technology. NatureWorks LLC makes Ingeo, a PLA.
== Applications==
Chemically recycled polyester fibres maintain the same quality as virgin polyester fibres in perpetuity.
Mechanically recycled polyester fibres can be of almost equal quality to virgin polyester, depending on the quality of raw materials. Some producers use low quality materials which result in low quality fibre.
Mechanically recycled polyester fibres can be blended with other fibres to maintain strength and quality for applications in a variety of fabric constructions—activewear, intimates, outdoor wear, T-shirts, trousers, etc.
Polylactide (PLA) is still a developing technology, and currently can be used for applications of bedding and apparel.
==Marketing opportunities==
'''x% recycled content''' Regulations require stating percent recycled if not 100% recycled content. In some cases where recycled polyester affects the aesthetic of the garment, craft marketing messages to turn potential negatives into positives.<br />
'''antimony-free''' If non-antimony polyester is used.<br />
'''alternative dyes''' If used.<br />
'''made from renewable source''' If PLA is used.
==Innovation opportunities==
==Company 1. Although creating different blends of recycled polyester with recycled cotton, organic cotton, etc., is good in the short term, know that these blends make it difficult to recycle at End of Use stage, and create liabilities and waste. When designing fibre blends, consider what happens after End of Use. 2. Design garments and products with reusable elements and for easy disassembly. Design the product so that trims, tags, buttons, etc. can be easily separated from the main body of the product at the end of its useful life, to enable easy in-house recycling. Create collection systems for the products. Collect, disassemble, reuse. 3. Look for cross-sector marketing opportunities==. For example, partner with a soft drinks brand to use their PET bottles in fabrics, or partner with garment collection charity to establish a long term collection facility where customers can drop their closed loop recyclable polyester garments. 4. Investigate alternative technologies for colouring polyester fabrics, such as AirDye, which eliminates water from the dyeing process.[17] Explore unique aesthetics achieved from using this process. 5. Design garments that are 100% polyester, including trims, so garments can be chemically recycled easily at the end of use. 6. Design products so that non-polyester trims can be easily separated from the main body of the product at the end use, to enable easy polyester recycling. 7. Design 100% degradable garments that are made from 100% PLA and work directly with the fibre-producing company to ensure performance and proper application. Create in-store take-back program for customers and partner with a local compost facility to ensure optimum conditions for garment to degrade properly. 8. Get your product Cradle to Cradle Certified. The Cradle to Cradle CertifiedTM Product Standard is a multi-attribute, continuous improvement methodology that provides a path to manufacturing healthy and sustainable products. The Standard rewards achievement in five categories and at five levels of certification. An accredited assessor will help to assess and optimize your product.
==Sources==
# https://www.indotextiles.com/download/Fibre%20Year%202009_10.pdf
# https://www.swicofil.com/pes.html
# https://www.nyfashioncenterfabrics.com/polyester-fabric-info.html
# https://www.ecouterre.com/could-polyester-be-the-next-eco-friendly-fabric/
# makewealthhistory.org/2010/06/11/how-much-oil-is-there-left-really/
# https://www.guardian.co.uk/environment/2010/jun/09/sir-david-king-dwindling-oil-supplies
# Athleta Webinar: “Textile Fibres & Sustainability.” Charlene Ducas. October 29, 2012
# “Monthly and cumulated Crude Oil Imports (volumes and prices) by EU and non EU country,” 2012.
# ec.europa.eu/energy/observatory/oil/import_export_en.htm
# Grose, Lynda and Kate Fletcher. Fashion & Sustainability: Design for Change. London: Laurence King Publishing Ltd, 2012.
# https://www.epa.gov/ttnchie1/le/acrylon.pdf
# https://www.ecouterre.com/is-synthetic-clothing-causing-microplastic-pollution-in-oceans-worldwide/
# The Textile Dyer, “Concern over Recycled Polyester,” May 13, 2008,
# oecotextiles.wordpress.com/2009/07/14/why-is-recycled-polyester-considered-a-sustainable-textile/#_ftn6
# https://www.teijin.co.jp/english/news/2012/ebd120809.html
# textileexchange.org/sites/default/files/eco_fibre.pdf
# https://www.technologystudent.com/joints/pla1.html
# Boh, Richard. Personal Interview. 25 February 2014.
# https://www.OEKO-TEK.com/media/downloads/Factsheet_OETS_100_EN.pdf
# http://www.teijin.com/products/chemicals/hmf.html
# http://www.jmcatalysts.com/pct/news2.asp?newsid=65