PA66 Alternatives for Airbag Yarn: PET, PA6 and Polymer

The short answer

PA66 remains the standard airbag yarn. Its melting point is close to PET's, but according to a patent filing by INVISTA (a nylon 66 airbag fiber maker) it has higher heat capacity and heat of fusion, so it resists hot inflator gas better. It also has good tear and seam strength. The one alternative in commercial use at scale is high-tenacity polyester (PET) yarn. Wood Mackenzie put polyester at about 20% of the global airbag business in 2019. Patent literature describes it as suited mainly to side curtain bags, which run at lower pressure and temperature. The trade-offs are heavier fabric and lower tear and seam strength. PA6 melts about 40°C lower, and we found no confirmed commercial airbag use. Bio-based PA4,10 appears in patent filings; we found no production program. For most buyers, the realistic alternative to one PA66 yarn supplier is another qualified PA66 or PET source. ResinBridge supplies polymer (chips and pellets), not yarn or fabric.

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Who this page is for

Searches for alternatives to a specific producer’s PA66 airbag fiber come from two groups: yarn and fabric buyers who want a second source, and polymer buyers who want PA66 or PET resin for spinning, compounding or molding. We supply the second group. ResinBridge sources polymer chips and pellets through our supply partners. We do not make or sell yarn, fabric or cushions. If you buy finished airbag yarn, the qualified yarn makers are your route, and the facts below should help frame that conversation.

For the wider nylon supply picture, see PA66 shortage alternatives. For fiber-grade nylon chips, see nylon fiber and monofilament resin.

Why PA66 dominates airbag fabric

An airbag cushion must hold low air permeability, absorb deployment energy and survive hot gas from the inflator at the seams. Producer patents describe nylon 66 as the usual fiber because of its impact and heat resistance. A Canadian patent filing by INVISTA, which sells nylon 66 airbag fiber, compared commercial nylon 6,6 and polyester airbag yarns and gives this thermal reason:

Property	Polyester (PET)	Nylon 6,6
Melting temperature	About 528 K (255°C)	About 531 K (258°C)
Specific heat	1.3 J/g·K	1.67 J/g·K
Heat of fusion	130 kJ/kg	203 kJ/kg

Values as reported in Canadian patent application CA 2813047 (INVISTA, now abandoned). Other sources report slightly different melting points by method.

Heat capacity, not melting point. The two polymers melt at about the same temperature. PET heats faster and melts sooner under hot gas because it has lower heat capacity and heat of fusion.
Typical yarn. One Toray patent claims PA66 airbag multifilament at 200–700 dtex, 1–2 dtex per filament, 8–10 cN/dtex tenacity and 20–25% elongation, with examples at 235, 280, 350 and 470 dtex. The Canadian filing lists two commercial 470 dtex nylon 6,6 airbag yarns at 81 and 86 cN/tex.
Coated and uncoated. PA66 airbag fabric is made both silicone-coated and uncoated. One patent lists coatings of 15–60 g/m².

Polyester (PET) airbag yarn: where it is used

Share and cost. Wood Mackenzie (September 2019) said polyester is typically half the cost of nylon and was likely to keep increasing its current 20% share of the global airbag business in certain airbag categories. It put global airbag yarn demand at 164 ktpa then. We found no newer public figure from a source of that standing.
Where it fits. The INVISTA filing notes that side curtain modules run at lower pressures and temperatures, so suitable polyester yarns can be acceptable there but not in frontal and side impact modules. Hot creep around the seams is described as the main failure mode, addressed with heavier fabric or lower design stress.
Trade-offs. An SAE paper by INVISTA authors (2014) says PET has been adopted in a small number of airbag programs to reduce supply concerns, with trade-offs of higher weight and lower tear and seam properties. INVISTA sells nylon airbag fiber, so read it with that in mind.
Who makes it. Kolon Industries signed a 2015 contract to supply one-piece-woven polyester side curtains to Autoliv for Ford programs. Hyosung holds patents on PET airbag fabric, and KED Global reported in 2021 that GST, Hyosung’s airbag affiliate, had invented the world’s first PET-based airbag. Indorama Ventures’ Scottsboro, Alabama site (Indorama Ventures Mobility Scottsboro) lists both PA and PET yarn spinning. Performance Fibers supplied the commercial polyester airbag yarns tested in the Canadian patent filing.
Why it moves slowly. Wood Mackenzie notes that airbag modules cannot easily be changed once specified on a new car model, so material changes usually happen at a new program.

PA6, PA6/66 and bio-based polyamides

PA6. A PHP Fibers patent filing compared 235 dtex yarns: PA6 melted at 215°C vs. 255°C for PA66, with tear strength of 55 vs. 70 cN/tex. Some patents allow nylon 6 but prefer nylon 66. We found no confirmed commercial PA6 airbag program. See nylon 6 vs. nylon 66.
Bio-based polyamides. The same PHP Fibers filing claims airbag fabric from polyamides made with at least 60% bio-based monomer, naming PA4,10, PA6,10, PA8,10 and PA10,10. Its PA4,10 example melted at 250°C with 73 cN/tex tenacity. That is patent data, not proof of a production program.
PA56 and PA510. We found no reputable source showing either in commercial airbag yarn, so we do not list them as alternatives.
Recycled PA66. Toray has reported recovering PA66 from silicone-coated airbag fabric scrap as an injection-molding resin, not as yarn. It noted that the high viscosity of airbag yarn polymer limits high-flow, thin-wall molding uses.

Airbag fiber options compared

Fiber	Strengths	Limits	Where used	Status
PA66, high tenacity, heat-stabilized	Highest heat capacity and heat of fusion here; tear and seam strength	Supply tied to the adiponitrile (ADN) chain, which has been concentrated in a few plants; costs more than PET	Driver, passenger, side, curtain and knee bags	The standard
PET, high tenacity	Lower cost; lower moisture; dimensionally stable	Lower heat capacity; hot creep at seams; heavier fabric for the same job	Mainly side curtain and one-piece-woven bags	Commercial; about 20% of the airbag business in 2019 (Wood Mackenzie)
PA6	Made from caprolactam, outside the ADN chain	About 40°C lower melting point; lower tear strength in one comparison	Comparison examples in patents	No confirmed commercial program found
Bio-based PA4,10 and similar	Renewable content; PA4,10 melts near PA66	Limited supply; no published qualification	Patent examples	Development

Summary of the sources listed below. Program use and status change over time; confirm with the yarn maker or module supplier.

What the polymer has to be

PA66 for airbag yarn. One Toray patent claims PA66 at a sulfuric acid relative viscosity of 3 to 4 (preferably 3.3–3.8), made by solid-state polymerization. Its example adds a copper and halide heat stabilizer (copper acetate at about 68 ppm copper, with potassium iodide and potassium bromide). Sulfuric RV does not convert one for one to the formic-acid values on U.S. sheets. See nylon fiber resin.
PET for airbag yarn. A Hyosung patent calls for PET chip at 0.8–1.3 dL/g intrinsic viscosity (its examples use 1.06) and says yarn below 0.8 dL/g is not suitable. Another filing describes melt polymerization to about 0.6 dL/g followed by solid-state polymerization. See PET intrinsic viscosity grades.
Much of it is made in-house. Indorama’s Scottsboro site lists PA polymerization and SSP alongside spinning. Asahi Kasei describes continuous polymerization and direct spinning for its Leona PA66. The merchant chip market for airbag yarn is therefore smaller than total airbag demand suggests.

Why buyers look for alternatives: PA66 supply

A concentrated intermediate. PA66 depends on adiponitrile (ADN). Plastics Technology reported in 2018, citing PolySource, that ADN came from four high-volume plants (three in the U.S., one in France) after seven force majeure declarations across the U.S. and Europe in the first two months of that year.
Airbag prices followed. Toray raised airbag nylon 66 yarn and fabric prices from December 2018 shipments, citing tight PA66 polymer supply due to the ADN shortage.
New capacity. INVISTA inaugurated a 400,000-ton-per-year ADN plant in Shanghai in 2022, which it said could support 800,000 tons a year of nylon 6,6.
INVISTA’s nylon fiber review. In April 2024 INVISTA said it was exploring options for its nylon business, including airbag and industrial fibers. In April 2025 INVISTA said it had decided to hold the business. In January 2026 it proposed ending production at its Gloucester, England site and moving those operations to its Kingston, Canada facility.
Practical takeaway. Keep a second qualified source, either another PA66 supplier or, for suitable programs, a PET design. Also watch the ADN chain that sets PA66 availability. See resin allocation and force majeure.

The qualification reality

Fabric tests. Airbag fabric work commonly uses ASTM D5822 (seam strength of inflatable restraint cushions) and ASTM D6479 (edgecomb resistance), which ASTM describes as useful for airbags where seam stress is a major concern. Patents also cite ASTM D737 (air permeability), D5035 (fabric tensile), D2261 (tear) and D885 (yarn tensile).
Deployment and aging. Module makers run deployment tests after heat aging; one patent describes deployment after 4 hours at 85°C. Vehicle-level occupant protection is covered in the U.S. by FMVSS 208.
Who signs off. A yarn or polymer change is approved by the fabric weaver, the module supplier and then the vehicle maker. Wood Mackenzie notes that module makers and automakers are increasingly reluctant to deal with smaller single-region yarn and fabric producers.
Time. Because modules are rarely re-specified mid-program, the realistic window for a material change is a new vehicle program.

Where we fit, and what to send us

We quote polymer, not yarn. That fits these buyers:

Spinners and compounders who need PA66 or PET chips to a viscosity, stabilizer and moisture spec
Molders and compounders looking for PA66 alternatives in molded parts. See PA66 shortage alternatives.
Buyers of post-industrial PA66 where the end use allows recycled content

To quote, send:

Polymer (PA66, PA6, PET) and end use
Viscosity with the method (sulfuric or formic RV, VN, or PET IV in dL/g)
Heat stabilizer, luster (TiO2) and end-group needs
Moisture as delivered, and packaging (lined gaylords or bags)
Annual volume, release size and ship-to location

A polymer chemist reviews every request and tells you plainly whether our supply partners can meet a high-viscosity, heat-stabilized spec. Every prime lot ships with a supplier COA, from one gaylord to a railcar.

Common questions

What is the main alternative to PA66 in airbag yarn?

High-tenacity polyester (PET) yarn. Wood Mackenzie put it at about 20% of the global airbag business in 2019, with patent literature pointing mainly to side curtain bags, which run at lower pressure and temperature. An INVISTA filing says hot creep at the seams is handled with heavier fabric or lower design stress.

Why not use PA6 for airbags?

PA6 melts about 40°C lower than PA66 (215 vs. 255°C in one patent comparison) and showed lower tear strength. We found no confirmed commercial PA6 airbag program.

Does ResinBridge sell airbag yarn?

No. We supply resin: PA66, PA6 and PET chips and pellets, plus other engineering polymers, to spinners, compounders and molders. For finished airbag yarn or fabric, work with a qualified yarn maker.

Did INVISTA exit the airbag fiber business?

Not as of INVISTA's latest releases we found. INVISTA said in April 2024 that it was exploring options for its nylon fibers business, including airbag and industrial fibers. In April 2025 it said it had decided to hold the business. In January 2026 it proposed consolidating some sites, including ending production at Gloucester, England.

Sources

Related pages (6)

Nylon fiber and monofilament resin PA66 shortage alternatives Nylon 6 vs. nylon 66 PET intrinsic viscosity grades Technical textiles resin Resin allocation and force majeure

PA66 alternatives for airbag yarn: what is used, what is not, and what it means for polymer buyers