This guide is for engineers, product designers, procurement teams and manufacturers. It covers the chemistry, grade families, properties, the Nylon 6 comparison, applications and how to source PA66 in India.
Key Takeaways
- PA66 is made from hexamethylenediamine and adipic acid, six carbons each.
- Strength, stiffness and heat resistance depend heavily on reinforcement and moisture state.
- Main uses: automotive, electrical, wire and cable, machinery, and fibres.
- Choose the grade by temperature, humidity, load, flame rating and total part cost.
What Is Nylon 66 Plastic and How Is It Made?
What Nylon 66 means
Nylon 66, also called PA66, is a semi-crystalline thermoplastic that can be melted and reshaped. The same polymer family appears as resin pellets, spun fibre, film, extruded profiles and injection-moulded parts. The resin is the raw material; the others are conversions of it.
The name is chemistry shorthand. Each monomer, hexamethylenediamine (HMD) and adipic acid, contains six carbon atoms. Hence "6,6".
How Nylon 66 is manufactured
Manufacture follows four main steps:
- HMD and adipic acid react in water to form nylon salt.
- Heat and pressure drive condensation polymerisation, with water vented off.
- Molten polymer is cooled in a water trough and cut into pellets.
- Pellets are tested, then melted again for moulding, extrusion, film or fibre spinning.
Molecular weight depends on monomer balance, and deviations alter viscosity and final performance. Processing matters too: excess moisture in the melt splits chains and cuts mechanical properties. BASF's Ultramid A3K lists melt temperatures of 280-300 °C for injection moulding and extrusion.
Nylon 66 grades and forms
Common families include:
- Unfilled (BASF Ultramid A3K)
- Glass-fibre filled at 15%, 30% or 50% (for example A3WG3, A3EG6, A3EG10)
- Heat-stabilised (the "W" designation)
- Impact-modified (A3ZG6)
- Mineral- or glass-bead-filled compounds
- Flame-retardant, such as MOCOM Altech A2030/547 at UL 94 V-0 (0.75 mm) and CTI 600 V
- Recycled-content versions of some compounds
Not every supplier offers every variant. Always read the exact datasheet for moisture conditioning, reinforcement level, colour, flame rating and processing needs. Datasheet values are guide values, not guaranteed part properties.
Key Properties of Nylon 66
Mechanical and thermal performance
The table compares BASF datasheet values. D/C means dry/conditioned.
| Property | PA66 A3K (unfilled) | PA66 A3EG6 (GF30) | PA6 B3S (unfilled) |
|---|---|---|---|
| Tensile modulus, ISO 527, MPa | 3,000/1,100 | 10,000/7,200 | 3,500/1,200 |
| Tensile strength, MPa | Yield 85/50 | Break 190/130 | Yield 90/45 |
| Notched Charpy, 23 °C, kJ/m² | 5/20 | 11/20 | 4/50 |
| Melting point, °C | 260 | 260 | 220 |
| HDT at 1.8 MPa, °C | 75 | 250 | 65 |
Yield stress and stress at break are different quantities, so don't compare them directly.
Reinforcement transforms the picture. Glass fibre lifts heat deflection temperature from 75 °C to 250 °C, which is why GF grades dominate under-bonnet work. Part geometry, temperature and load duration still change real performance.
Moisture, chemical and environmental behaviour
PA66 absorbs water. A3K reaches 2.5-3.1% at 23 °C/50% RH and 8-9% at saturation. The effects:
- Conditioned modulus drops sharply (3,000 to 1,100 MPa for A3K)
- Impact toughness rises
- Parts grow dimensionally, depending on humidity, time, temperature and wall thickness
Always ask whether a datasheet figure is dry or conditioned.
BASF lists resistance to lubricants, fuels and coolants, and Ascend offers Vydyne HR for hot cooling-system hydrolysis. No grade resists every chemical indefinitely, so test with your actual fluids, temperatures and durations.
Design limitations and trade-offs
- Creep: sustained load at temperature needs grade-specific allowance data from the supplier.
- Warpage: glass-filled A3EG6 shrinks 0.5% parallel and 1.0% transverse to flow, so mould design must account for it.
- UV: natural PA66 cable ties are not UV-stabilised; outdoor use needs a stabilised grade.
- Additives: flame retardants, glass and stabilisers help one property but can affect flow, impact, cost, recyclability or tooling.
Nylon 66 vs Nylon 6
Structural and performance differences
PA66 uses HMD plus adipic acid; PA6 polymerises from a single monomer, caprolactam. Processing windows differ as well:
| Property | PA66 A3K | PA6 B3S |
|---|---|---|
| Melt temperature | 280-300 °C | 250-270 °C |
| Mould temperature | 60-80 °C | 40-60 °C |
| Melting point | 260 °C | 220 °C |
| Equilibrium moisture | 2.5-3.1% | 2.6-3.4% |
A manufacturer comparison positions PA66 as the higher-cost material, though no fixed premium applies.
Choosing between the two materials
PA66 is not automatically better. Dry unfilled PA6 B3S has a yield stress of 90 MPa against 85 MPa for A3K. Its conditioned impact value is 50 kJ/m² against 20 kJ/m².
A quick framework:
- High temperature or heat ageing: investigate PA66 melting point and HDT
- Repeated loading and wear: compare fatigue and abrasion data at your conditions
- High humidity or tight tolerances: compare conditioned properties and shrinkage
- Impact toughness, easier processing or cost pressure: PA6 may suit better
Nylon 66 Applications Across Industries
Automotive and mobility
Ascend lists PA66 intake manifolds, charge-air-cooler ducts and cylinder-head covers. Heat resistance, stiffness and chemical resistance to oils and coolants drive these choices. For electric vehicles, common PA66 uses include:
- Battery covers and frames
- BMS housings
- High-voltage switches, connectors and charging plugs
These parts need verified flame rating, insulation and dimensional stability.
Electrical, electronics, wire and cable
- BASF A3K R01 terminal blocks and cable connectors: UL 94 V-2 at 0.4 mm, electrical RTI 125 °C
- A3K tracking resistance: CTI 600 (IEC 60112)
- HellermannTyton T50R natural PA66 cable ties: UL 94 V-2, IEC 62275, -40 to +85 °C, not UV-stabilised
BIS lists IS 13464:1992 for nylon 66 moulding and extrusion materials. These ratings belong to named grades, not PA66 in general.
Industrial, machinery and consumer products
Typical industrial uses include:
- Unfilled A3K for bearings and gears
- A3EG6 for machinery housings, cooling fans and water-cooling containers
PA66 replaces metal where weight, noise and mouldability matter. For agricultural or outdoor parts, weather, fertilisers, oils and water exposure should guide grade selection.
Fibres, technical textiles and regulated uses
Fibre follows a different route: molten polymer is spun and stretched. Toray and Ascend identify PA66 tyre cord and airbag fabric, plus conveyor belts, hoses and lifting straps. These are judged on tenacity, not moulding benchmarks.
Food-contact and medical uses are grade-specific. BASF's A3K FC Aqua declaration references 21 CFR 177.1500 and EU 10/2011. Ascend's HiDura MED AG33 declares ISO 10993-5/-10 compliance but excludes implantation. Verify approvals for your exact grade.
How to Choose and Source Nylon 66
Match the grade to the application
Define these before requesting quotes:
- Operating and peak temperature
- Continuous and peak loads
- Humidity, chemical and UV exposure
- Electrical and flame requirements
- Colour and tolerances
- Moulding method and reinforcement
- Expected service life
Cost and commercial evaluation
No credible universal India price exists, and public current quotations are scarce. IMARC's pricing report names adipic acid, HMD, energy and processing as cost drivers.
Other factors that move price include:
- Reinforcement and additives
- Volume, packaging and logistics
- Testing, certification and exchange rates
Get written quotations for your exact grade.
Resin price is not total part cost. Count tooling, drying, scrap, cycle time, inspection and failure risk. A cheaper resin that warps or fails costs more.
Supplier qualification and scale-up
Before committing, check:
- Technical datasheets and certificates of analysis
- Batch consistency and traceability
- Moisture control: BASF suggests drying A3EG6 at 80 °C for 4 hours to 0.03-0.06% moisture
- Sample approval and application trials
- Scale-up support
Distil, a Mumbai-headquartered materials supplier with an R&D base in Navi Mumbai, lists PA6 and PA66 among its engineering plastics, including LG Chem LUMID grades.
Its R&D team manages application-specific trials, and its partner network and supply-chain visibility support scale-up. Confirm availability and suitability of your required PA66 grade first. Pricing is on request.
Frequently Asked Questions
How much does Nylon 66 cost?
Price varies by grade, reinforcement, additives, volume, supplier, logistics and market conditions. Request current India-specific quotations for your exact grade.
What is Nylon 66 used for?
Automotive under-bonnet parts, electrical connectors, cable ties, machinery gears and bearings, consumer products, and technical fibres such as tyre cord and airbags.
What is the difference between Nylon 66 and Nylon 6?
PA66 uses two six-carbon monomers; PA6 uses caprolactam. PA66 typically melts higher (260 vs 220 °C) and costs more; PA6 processes at lower temperatures.
Is Nylon 66 a plastic?
Yes. It is a semi-crystalline thermoplastic that can be melted and made into moulded parts, fibres, films and extruded products.
What are the properties of Nylon 66?
Strength, stiffness, abrasion resistance, fatigue performance and good heat behaviour, with notable moisture absorption. Values depend on grade, reinforcement and conditioning.
What does '6,6' in Nylon 6/6 mean?
Both monomers, the diamine (hexamethylenediamine) and the diacid (adipic acid), contain six carbon atoms.
