Nylon is not a single material — it is a family of polyamides (PA) with melting points ranging from 178°C (PA12) to over 320°C (PA46, PA6T, PA9T). Choosing the right nylon grade for a given service temperature, processing line, or cost target requires understanding how these melting points differ and why.
This hub guide compares the melting points, glass transition temperatures, heat deflection temperatures, and continuous use temperatures of every commercially significant nylon grade — so procurement teams and design engineers can shortlist the correct polyamide before diving into specific TDS data.
1. Direct Answer: What Is the Melting Point of Nylon?
There is no single nylon melting point. Melting point (Tm) depends on the specific polyamide grade:
- PA6: 220–225°C
- PA66: 255–265°C
- PA11: 185–195°C
- PA12: 178–180°C
- PA46: 290–295°C
- PA6T (semi-aromatic): 310–325°C
- PA9T / PA10T (semi-aromatic): 300–320°C
Semi-crystalline polyamides (all listed above) show a sharp Tm on DSC. Amorphous polyamides (PA6-3-T, PACM12) have no true Tm — they soften gradually above their Tg (~150–160°C).
Key takeaway: When someone asks “what is nylon’s melting point,” the correct answer is a grade table, not a single number. Selecting a nylon by melting point alone is a common procurement error — HDT and CUT are what determine end-use fit.
2. Complete Nylon Melting Point Comparison Table
| Nylon Grade | Chemistry | Tm (°C) | Tg (°C, dry) | HDT @ 1.8 MPa (°C, unfilled) | Continuous Use (°C) | Water Absorption (24h) |
|---|---|---|---|---|---|---|
| PA6 | Polycaprolactam | 220–225 | 50–60 | 60–100 | 80–120 | 1.6–1.9% |
| PA66 | Hexamethylenediamine + adipic acid | 255–265 | 50–70 | 70–100 | 100–120 | 1.2–1.5% |
| PA610 | Hexamethylenediamine + sebacic acid | 215–225 | 50–60 | 55–90 | 90–110 | 0.4–0.5% |
| PA612 | Hexamethylenediamine + dodecanedioic acid | 210–220 | 45–55 | 55–85 | 90–110 | 0.3–0.4% |
| PA11 | 11-aminoundecanoic acid (bio-based) | 185–195 | 40–50 | 50–55 | 80–100 | 0.3–0.4% |
| PA12 | Laurolactam | 178–180 | 35–45 | 50–55 | 80–100 | 0.2–0.3% |
| PA46 | Tetramethylenediamine + adipic acid | 290–295 | 75–85 | 150–160 | 150–170 | 3.5–4.0% |
| PA6T/6I (semi-aromatic) | Hexamethylenediamine + terephthalic acid (copolymer) | 310–325 | 110–125 | 110–130 | 120–150 | 0.5–0.8% |
| PA9T (semi-aromatic) | Nonanediamine + terephthalic acid | 300–310 | 120–130 | 120–140 | 135–160 | 0.2–0.3% |
| PA10T (semi-aromatic) | Decanediamine + terephthalic acid | 310–320 | 125–135 | 130–150 | 140–160 | 0.2–0.3% |
| PPA (PA6T-based blends) | Various semi-aromatic copolymers | 290–320 | 110–135 | 115–140 | 130–160 | 0.3–0.6% |
| PA6-3-T (amorphous) | Trimethyl-hexamethylenediamine + terephthalic acid | No true Tm | ~150 | 130–140 | 100–130 | 0.6–0.8% |
Values are typical industry ranges for unfilled grades. Actual data varies by manufacturer, molecular weight, and test method. Verify against supplier TDS for critical applications.
3. Why Do Different Nylons Have Different Melting Points?
Three structural factors set a polyamide’s melting point:
1. Amide group density (CH₂/CONH ratio)
Higher amide density → more hydrogen bonds per unit length → higher Tm. PA6 and PA66 have amide groups every 6 carbons, giving Tm 220–265°C. PA12 has amide groups every 12 carbons, giving Tm only 178–180°C. This is why long-chain nylons (PA11, PA12) melt low but also absorb less water.
2. Chain symmetry
More symmetrical repeat units pack more tightly into crystals, raising Tm. PA66 (255–265°C) melts higher than PA6 (220–225°C) despite similar amide density because PA66’s diamine + diacid repeat unit is more symmetrical than PA6’s single-monomer chain.
3. Aromatic rings in the backbone (semi-aromatic PPA)
Terephthalic acid or isophthalic acid stiffens the chain and boosts thermal stability. This is how PA6T, PA9T, PA10T, and PA46 reach Tm 290–325°C — enough to survive lead-free solder reflow (~260°C peak) in surface-mount electronics.
4. PA6 vs PA66 vs PA11/12: Which Nylon Family Should You Choose?
| Decision Driver | Best Choice | Why |
|---|---|---|
| Lowest cost / general purpose | PA6 | Cheapest polyamide; easiest to process; broad grade availability |
| Higher heat + stiffness | PA66 | 40°C higher Tm than PA6; better creep resistance; automotive workhorse |
| Under-the-hood, engine bay | PA66-GF30 or PPA | HDT 240–255°C (PA66-GF30); PPA for >180°C air-side use |
| Low moisture absorption / dimensional stability | PA12 > PA11 > PA612 > PA610 | Long-chain nylons absorb 0.2–0.5% vs. PA6’s 1.6–1.9% |
| Chemical / fuel resistance | PA12, PA11 | Standard for fuel lines, brake tubes, pneumatic hoses |
| SMT / lead-free reflow tolerance | PA6T, PA9T, PA46 | Tm > 290°C survives 260°C peak reflow |
| Bio-based sourcing | PA11 (100% castor oil), PA610 (partly) | Renewable feedstock for ESG-driven programs |
| Optical clarity | Amorphous PA (PA6-3-T, PACM12) | No crystallites → transparent parts |
5. Melting Point Is Not the Service Temperature Ceiling
A common procurement error: specifying nylon by Tm. Melting point defines the processing floor, not the service ceiling. For end-use performance, use:
- HDT (Heat Deflection Temperature, ISO 75) — how much load-bearing temperature the part can take before deflecting.
- CUT / RTI (Continuous Use Temperature, UL 746B) — long-term thermal endurance, typically 100–150°C below Tm.
- Vicat Softening Point (ISO 306) — indentation resistance at temperature; ~30–50°C below Tm.
Example: PA66 has Tm 260°C, but unfilled PA66 loses stiffness above ~100°C (its Tg + moisture effect). Only PA66-GF30 with HDT 240–255°C qualifies for under-the-hood 150°C service.
6. Processing Temperature Windows (Injection Molding)
| Nylon Grade | Melt Temp (°C) | Mold Temp (°C) | Drying (°C / h) | Target Moisture |
|---|---|---|---|---|
| PA6 | 240–270 | 60–90 | 80 / 4–8 | < 0.10% |
| PA66 | 270–300 | 60–100 | 80 / 4–8 | < 0.10% |
| PA610 / PA612 | 240–270 | 60–90 | 80 / 4–6 | < 0.10% |
| PA11 | 220–250 | 40–80 | 75 / 3–4 | < 0.10% |
| PA12 | 210–240 | 40–80 | 75 / 3–4 | < 0.10% |
| PA46 | 310–330 | 100–120 | 100 / 4–6 | < 0.05% |
| PA6T / PPA | 320–340 | 120–150 | 90–100 / 4–6 | < 0.05% |
| PA9T / PA10T | 320–340 | 120–150 | 90–100 / 4–6 | < 0.05% |
High-temp semi-aromatic grades (PA46, PA6T, PA9T, PA10T) need tight barrel control — the window between melt and degradation is narrow. Do not exceed 340°C.
7. Moisture, Hydrolysis, and Thermal Degradation
All polyamides are hygroscopic to some degree, but the effect is dramatic in short-chain nylons (PA6, PA66, PA46) and mild in long-chain nylons (PA11, PA12).
- Moisture as plasticizer: lowers effective Tg and HDT; does not shift Tm.
- Hydrolysis: wet nylon in the melt phase cleaves at the amide bond → molecular weight drops → mechanical properties fall permanently. Visually invisible but destructive.
- Thermal degradation (>300°C for PA6/66; >340°C for PPA): releases ammonia (NH₃), carbon monoxide (CO), and trace hydrogen cyanide (HCN). Local exhaust ventilation (LEV) is mandatory.
Rule of thumb: dry every nylon before molding, even long-chain grades. Target moisture < 0.10% for standard nylons and < 0.05% for high-temp semi-aromatics.
8. Nylon vs. Other Engineering Plastics — Melting Point Positioning
| Material | Type | Tm (°C) | Continuous Use (°C) | Positioning vs. Nylon |
|---|---|---|---|---|
| PP | Semi-crystalline | 160–170 | 80–100 | Cheaper, lower stiffness |
| POM | Semi-crystalline | 165–185 | 90–110 | Better dimensional stability, worse impact |
| PA6 / PA66 | Semi-crystalline | 220–265 | 80–120 | Reference nylon |
| PC | Amorphous | No true Tm | 115–130 | Transparent, brittle in notched impact |
| PBT | Semi-crystalline | 220–225 | 120–140 | Similar Tm to PA6 but far lower moisture uptake |
| PPS | Semi-crystalline | 280–290 | 200–220 | Above PA66, below PEEK; chemically inert |
| PA46 / PPA | Semi-crystalline | 290–325 | 150–170 | Nylon’s top tier for reflow / under-hood air |
| PEEK | Semi-crystalline | 340–345 | 240–260 | Above all nylons; ~10× the cost |
9. Frequently Asked Questions
What is the melting point of nylon?
It depends on grade. Common values: PA6 ≈ 220–225°C, PA66 ≈ 255–265°C, PA12 ≈ 178–180°C, PA46 ≈ 290–295°C, PA6T ≈ 310–325°C.
Which nylon has the highest melting point?
Semi-aromatic PA6T (≈325°C peak) and PA46 (≈295°C) are the highest-melting commercial polyamides. They are used for SMT connectors and engine-air-side parts.
Which nylon has the lowest melting point?
PA12 (≈178–180°C), followed by PA11 (≈190°C). Both are long-chain, low-moisture nylons used for fuel lines and flexible tubing.
Does nylon melt or burn?
Nylon melts first, then thermally degrades above ~300°C (or ~340°C for semi-aromatics), releasing toxic gases (NH₃, CO, HCN). It does not “burn cleanly” — always process below degradation temperature and use LEV.
Is nylon’s melting point higher than PP or ABS?
Yes. PP melts at 160–170°C, ABS has no true Tm (softens around 100°C). All commercial nylons except pure PA12 melt higher than PP. PA6/66/46/PPA all melt far above the ABS softening range.
Can I use melting point to compare nylon grades for a hot application?
No. Use HDT and Continuous Use Temperature (CUT/RTI). A nylon’s service ceiling is typically 100–150°C below its Tm.
Does glass fiber reinforcement change nylon’s melting point?
No. Glass fiber does not alter the polymer matrix’s Tm, but it dramatically raises HDT (e.g., PA66-GF30 jumps from ~90°C to ~250°C at 1.8 MPa) and reduces creep.
10. How to Select a Nylon: Decision Flow
- Define service temperature → check CUT and HDT tables, not Tm alone.
- Define moisture environment → wet/humid → prefer PA11, PA12, PA610, PA612, or PPA.
- Define chemical exposure → fuels/oils → PA11, PA12; strong bases → all nylons acceptable; strong acids → avoid all nylons.
- Define mechanical load → high stiffness/creep → PA66-GF or PPA-GF.
- Define cost target → PA6 cheapest → PA66 mid → PA610/612 higher → PA11/12 premium → PA46/PPA highest.
- Verify processing capability → does your machine reach 320°C+ for PPA/PA46? Do you have a dehumidifying dryer? If not, restrict to PA6/PA66.
11. Data Sources & Disclaimer
Data compiled from publicly available TDS across major polyamide producers, plus ISO 11357 (DSC), ISO 75 / ASTM D648 (HDT), ISO 306 (Vicat), and UL 746B (RTI). Actual values vary by grade, manufacturer, molecular weight, and test method. For critical applications, always verify against the supplier’s official TDS.
12. Related Resources
- Plastic Raw Material Melting Point: Complete Guide
- PA6 Melting Point: Nylon 6 Melting Temperature & Processing Guide
- PA66 Melting Point: Nylon 66 Melting Temperature & Processing Guide
- PP Melting Point: Crystalline Melting Range & Processing Temperatures
- POM Melting Point: Acetal Melting Temperature & Processing Guide
- PA6 Water Absorption: High Moisture Uptake & Drying Requirements
- PA66 Water Absorption: Saturation Data & Dimensional Stability
