Nylon 6,6 and nylon 6 make up 90% of the global nylon market¹ — but when it comes to long-term performance in demanding applications, nylon 6,6 offers distinct advantages.
¹ Wood Mackenzie, November 2023.
At a molecular level, nylon 6,6 can have a higher density of hydrogen bonds compared to nylon 6, which gives nylon 6,6 unique advantages such as a 40°C higher melting point, improved thermal properties and superior durability, among other benefits. These performance properties make nylon 6,6 a preferred material in automotive parts, electrical components, industrial applications and performance textiles — especially in demanding environments.
Within the polymer molecule, nylon 6,6 has a symmetrical chain structure that allows for more uniform crystallization. This results in rapid formation of stable alpha crystals — up to 10 times faster than nylon 6,² due to the latter's non-symmetric structure (directionality along the chain length). Nylon 6,6 has significant advantages in:
Strength and durability: When load and strain are key concerns, nylon 6,6 has strong mechanical properties, including fatigue and creep resistance.
Abrasion and wear resistance: In applications where surfaces take a beating, nylon 6,6 delivers time and time again.³
Conditioned performance: Even in humid environments, nylon 6,6 retains its mechanical strength better compared to nylon 6, giving material selectors confidence when designing for these conditions.³
Chemical resistance: Nylon 6,6 has excellent compatibility with some harsh chemicals, which makes it an ideal choice for corrosive environments.³
² Penn State: Zhang, X.; Buzinkai, J.; Quinn, E.; Rhoades, A. Key Insights into the Differences between Bimodal Crystallization Kinetics of Polyamide 66 and Polyamide 6. Macromolecules 2022, 55 (20), 9220–9231
³ Nylon Plastics Handbook: Kohan M.I., 1995
when using same glass-fiber loading content
| Traits | Nylon 6,6 | Nylon 6 |
|---|---|---|
| Maximum short-term use temperature | 240°C | 200°C |
| Long-term heat-aging resistance | Very good | Very good |
| Mechanical strength, dry | Excellent | Excellent |
| Mechanical strength, conditioned | Very good | Good |
| Strength at elevated temperatures | Excellent | Good |
| Creep resistance | Very good | Ok |
| Fatigue resistance | Very good | Good |
| Impact resistance | Excellent | Excellent |
| Dimensional stability | Good | Ok |
| Fuels and chemical resistance | Excellent | Excellent |
| Hydrolysis resistance | Excellent | Ok |
| Efficiency of FR additives to obtain V-O | Very good | Good |
| Friction and wear resistance | Excellent | Ok |
For compounders: INVISTA supplies a wide range of nylon 6,6 feedstock polymers for automotive, electrical and electronics, industrial and consumer applications. From very low to very high viscosity levels, INVISTA's feedstock polymers form the backbone of compounding grades around the world.
For injection molders: INVISTA's direct-to-mold polymer grades offer a variety of features that meet molders' needs, including rapid crystallization, heat stabilization and high strength. With fast cycle times and consistent processing, INVISTA's lubricated nylon 6,6 polymers help molders save time and money.
When it comes to fiber spinning for textile applications, nylon 6,6 stands apart. Its rapid crystal formation gives fibers a high crystalline content, producing stable yarn properties. Compared to nylon 6, this results in superior toughness and better abrasion resistance — tangible differences that spinners, fabric weavers and end users notice and value.
Athleisure, performance apparel and commercial carpet all benefit from what nylon 6,6 brings to the fiber, with shape retention and color fastness being two proof points worth noting.
4 AATCC 61 Method 2A Colorfastness, internal lab.
For industrial applications such as airbags, tire cord, conveyor belts, sewing threads and more, nylon 6,6 provides key advantages:
³ Nylon Plastics Handbook: Kohan M.I., 1995
If you're ready to put our nylon 6,6 to work or would like to learn how INVISTA can support your applications, explore our products or connect with our team.
