MATERIAL GUIDE
PA6 vs PA66
Practical material knowledge for better sourcing decisions — written for industrial buyers, not polymer chemists.
TYPICAL REFERENCE VALUES FOR MATERIAL FAMILIES — EXACT VALUES DEPEND ON GRADE AND MANUFACTURER. GRADES AND SPECIFICATIONS ARE CONFIRMED WITH YOU BEFORE EVERY ORDER.
The Two Workhorse Nylons
PA6 (nylon 6) and PA66 (nylon 6/6) are the two most widely used engineering nylons, and for many machined parts either will work. The differences become important under load, at temperature, or when tolerances are tight.
PA66 typically offers higher tensile strength, higher modulus and better creep resistance than PA6. For structural parts under sustained load, PA66 is usually the stronger specification.
EDGE · PA66
PA66 has a higher melting point (~260°C vs ~220°C) and better performance at elevated temperature. PA6 softens earlier but is less prone to brittleness at low temperature and generally offers slightly better impact toughness.
EDGE · PA66
Both nylons absorb moisture, and both grow as they do — PA6 slightly more than PA66. This affects dimensions in tight-tolerance parts regardless of which you choose. For dimension-critical components in variable humidity, PET or POM are often better alternatives.
BOTH · CAVEAT
PA6 is generally the more economical of the two and is widely available in many sizes and filled grades (glass-filled, MoS₂-lubricated). PA6 is often chosen for large-diameter stock where cost adds up quickly.
EDGE · PA6
Side-by-Side Comparison
| Property | PA6 | PA66 |
|---|---|---|
| Tensile strength / modulus | High | Higher |
| Melting point | ~220°C | ~260°C |
| Impact toughness (low temp.) | Better | Good |
| Moisture absorption | Slightly higher | High |
| Relative cost | Lower | Mid |
Selection Guidance
CHOOSE PA6 WHEN
CHOOSE PA66 WHEN
WHEN DIMENSIONAL STABILITY DOMINATES THE REQUIREMENT, CONSIDER PET OR POM INSTEAD — SEND US THE APPLICATION AND WE WILL POINT YOU TO THE RIGHT FAMILY.
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