Sorona®

Overview

A branded PTT polymer platform using a partly bio-based input route. It is not elastane and is not simply PET polyester under another name.

Feel and behavior

Depends on the specified fiber grade, yarn and fabric construction.

Where you find it

See the linked underlying material and the producer’s product-specific documentation.

Source and geography

Sorona is a brand of Covation Biomaterials LLC, based near Newark, Delaware, which is owned by China's Huafon Group. DuPont commercialized Sorona in 2000 and sold its biomaterials business to Huafon in a deal announced in 2020 and closed in 2022. The generic fiber is poly(trimethylene terephthalate), PTT, a polyester. Covation states that Sorona is 37% bio-based by weight, from 1,3-propanediol (PDO) produced by fermenting corn sugar; the terephthalic acid portion is petroleum-derived.

Worth knowing

• Sorona's producer compares it against nylon 6, not PET, when claiming about 30% less energy and 63% fewer greenhouse gas emissions.
• Bicomponent Sorona yarns get their stretch from two polymers that shrink differently, which makes the filament curl like a coil spring.

Types, grades and fabrics

Types and grades

Sorona is sold as PTT polymer to licensed fiber makers, who turn it into several product forms. Continuous filament yarns, flat or textured, go into apparel fabrics; bicomponent filaments can pair PTT with another polyester so the two shrink differently and the yarn coils, giving mechanical stretch without elastane. Staple fiber is used in spun yarns, fill and insulation. Bulked continuous filament goes into carpets, which in the US may be labeled triexta. Covation also markets Sorona for faux fur. Its Common Thread program certifies fabrics from partner mills, and it has introduced apparel sub-brands for specific performance claims.

Fabrics and products

In apparel, Sorona appears in stretch wovens for trousers and outerwear, suiting and shirting that aims for wrinkle recovery, activewear knits, swimwear, and faux fur and fleece piles. Staple and fill versions are used in insulated jackets and bedding. In home furnishings, PTT carpet fiber is valued for resilience and stain resistance. Sorona is often blended with cotton, wool, nylon, polyester or spandex, so the stretch and hand of a fabric depend on the blend and construction.

Buying and care

How to judge quality

US labels may say polyester or triexta; EU labels say polyester. Look for the Common Thread certification on fabrics from partner mills, which Covation uses to identify certified fabrics made with its polymer, and for the stated Sorona percentage. In stretch wovens, pull the fabric widthwise and watch recovery: a good bicomponent Sorona fabric should snap back without bagging. Because PTT melts at a lower temperature than PET, poor finishing can leave a harsh or shiny surface; inspect for glazing. Claims that Sorona is 'plant-based' should say 37% bio-based by weight.

Care in detail

Wash at 30 to 40 C with like colors; Sorona blends generally tolerate machine washing, but follow the label for wool or elastane components. Skip high dryer heat: tumble low or line dry, since PTT softens at lower temperatures than standard polyester. Iron at a low to medium setting (about 110 to 150 C) with a press cloth on the reverse; excess heat can flatten texture or glaze the surface. Faux fur in Sorona should be shaken out, brushed gently when dry, and never ironed. Pretreat oily stains promptly. Carpets in PTT fiber resist many water-based stains but should be blotted quickly.

Care at a glance

Follow the finished product’s care label. A trademark does not specify the care needs of every blend or construction.

Environmental and social footprint

Sorona's brand materials state that producing the polymer uses about 30% less energy and releases about 63% fewer greenhouse gas emissions than producing nylon 6, per unit of polymer; the comparison is the producer's own and uses nylon 6 rather than PET as the baseline. The bio-based share depends on corn grown for fermentation, bringing agricultural land use, fertilizer and pesticides into the footprint, which the headline figures do not describe. No independent peer-reviewed life-cycle study of Sorona fiber was found for this entry. At the use stage, PTT is a polyester and, like PET, releases persistent microfibers in laundering; a 2021 review in Heliyon (Gaylarde and colleagues) summarizes evidence that synthetic textile laundering is a major microfiber source. PTT carpet and apparel waste is rarely recycled at present.

Tradeoffs

Producer claims apply to defined products and comparisons. This atlas does not independently certify performance, sourcing or environmental claims.

A useful question to ask: Which exact grade, composition and current producer documentation apply to this product?

Science

Data sheet

Engineered organic polymer

Polymer chemistry and fiber-forming conditions determine the starting material.

Structure and chemistry

PTT is an aromatic polyester formed from terephthalic acid (or its dimethyl ester) and 1,3-propanediol, a three-carbon diol, whereas PET uses two-carbon ethylene glycol. The odd number of methylene groups makes the chain adopt a helical, zigzag conformation in the crystal, so the molecule can extend and recover like a spring at small strains. PTT has a melting point of about 228 C and a glass transition of about 45 C, both lower than PET, and a lower initial modulus, which accounts for its softer hand.

From source to yarn

Covation describes a two-part supply chain. Bio-PDO is made by fermenting glucose from corn with an engineered microorganism, then purified; its main plant at Loudon, Tennessee, is a joint venture. The PDO is polymerized with terephthalic acid by melt polycondensation to PTT at Kinston, North Carolina. The polymer is sold as chip to fiber makers, who melt-spin, draw and texture it into filament yarn or bicomponent stretch yarns, or cut it into staple and carpet fiber.

Performance in use

PTT fibers show good elastic recovery at low extensions, better than PET and similar to nylon in published data, which gives mechanical stretch without elastane in some constructions. The lower glass transition allows disperse dyeing at lower temperatures than PET, often without carriers. Moisture regain is low, as for other polyesters, and PTT carpet fiber is marketed for stain resistance. It is thermoplastic and melts. Covation's life-cycle comparisons against nylon 6 are producer claims.

How it is identified

Burn behavior resembles polyester (melts, drips, sooty smoke, hard bead); burn tests are indicative only. FTIR identifies a terephthalate polyester, and differential scanning calorimetry separates PTT (melting about 228 C) from PET (about 250 to 260 C). Radiocarbon analysis could detect the bio-based carbon share. Sorona is often misdescribed as elastane or as a plant fiber; it is a partly bio-based synthetic polyester.

History

Timeline

1. 2000DuPont commercialized Sorona poly(trimethylene terephthalate), using 1,3-propanediol from corn-sugar fermentation. [1]
2. 2009The FTC adopted triexta as a US generic name for a polyester subclass based on 1,3-propanediol, covering PTT. [2]
3. 2020DuPont agreed to sell its biomaterials business, including Sorona, to Huafon Group for about 240 million dollars. [3]
4. 2022The sale closed and the business relaunched as Covation Biomaterials. [3]

Sorona connects industrial biotechnology with polyester-family performance materials. Its brand programs cover particular apparel and carpet applications.

The deeper record

PTT was known in polymer chemistry for decades but was costly because 1,3-propanediol was expensive. DuPont and partners developed a corn-sugar fermentation route to PDO, allowing DuPont to commercialize Sorona in 2000 and later scale bio-PDO at Loudon. In 2009 the FTC created the triexta subclass, reflecting carpet makers' interest in PTT. In 2020 DuPont agreed to sell its biomaterials unit to Huafon Group for about 240 million dollars; the deal closed in 2022 and the business was relaunched as Covation Biomaterials, which marked Sorona's 25th anniversary in 2025.

Labeling and law

Sorona is a trademark, not a generic name. In the US, 16 CFR 303.7(c) allows triexta as an alternative generic name for a polyester subclass in which at least 90 mole percent of the glycol is 1,3-propanediol; the FTC adopted it in 2009 on a petition from Mohawk, DuPont and PTT Poly Canada. Polyester is also permitted. In the EU, Regulation (EU) No 1007/2011 has no separate PTT name, so polyester applies. Bio-based content claims need substantiation.

This describes what rules and standards cover. It is not legal advice; jurisdiction, product form and current rule text control.

Frequently asked

Is Sorona spandex?

No. Sorona is a polyester, poly(trimethylene terephthalate), partly made from corn-derived 1,3-propanediol. Its molecular shape gives stretch and recovery, and bicomponent yarns coil like springs, but it is not a polyurethane elastomer.

Is Sorona plant-based?

Partly. The producer states that 37% of the polymer by weight comes from renewable plant sugars; the rest is petroleum-derived terephthalic acid. It is not biodegradable and behaves like other polyesters at end of life.

What does triexta mean on a label?

Triexta is a US generic name the FTC adopted in 2009 for a polyester subclass based on 1,3-propanediol, which covers PTT such as Sorona. It appears mostly on carpets. Polyester is also an allowed name.

Sources

• Sorona: Official product information
• Sorona: The Sorona story
• C&EN: DuPont biomaterial business emerges as the new firm Covation
• Federal Register (2009): Rules and Regulations Under the Textile Fiber Products Identification Act, triexta
• Journal of Polymers and the Environment: A new polymer platform for the future, Sorona from corn derived 1,3-propanediol
• Wiley: Poly(trimethylene terephthalate), Encyclopedia of Polymer Science and Technology
• Sorona: New website celebrates Common Thread fabric certification program and apparel sub-brands (press release)
• Sorona: Sorona celebrates 20th anniversary of first commercial run (press release)
• TEXINTEL: Sorona introduces a global preferred mill network
• Heliyon: Plastic microfibre pollution, how important is clothes' laundering? (Gaylarde et al., 2021)

Cite this page

Chaos. (2026). Sorona®. In Fibers of Earth: An independent textile atlas. https://www.hendrickresearch.com/fibers/materials/sorona/