PA12 — Polyamide 12
Polyamide 12
PA12 (polyamide 12) is the least hygroscopic polyamide, renowned for its dimensional stability and flexibility. It offers excellent chemical and stress-cracking resistance, making it the reference for tubing, fuel lines and cable jacketing.
- Mold temperature: 40-70°C
- Melt temperature: 230-270°C
- Shrinkage: 0.5-1.5%
- Density: 1.01-1.03
- Manufacturer grades: Rilsan AESNO TL (Arkema), Grilamid L25 (EMS-Grivory), Vestamid L1901 (Evonik)
Processing
PA12 absorbs little water, but drying for about 4 h at 80 °C is still recommended to ensure a consistent surface finish. Process the melt between 240 and 260 °C and regulate the mold between 40 and 70 °C. Its moderate shrinkage and low moisture uptake make stable dimensions easy to hold, but respecting the temperature profile remains key to avoiding surface defects.
Advantages
- Low water absorption: excellent dimensional stability
- Good flexibility and resistance to stress cracking
- Very good chemical resistance (fuels, hydrocarbons, salts)
- Good fatigue and impact resistance at low temperature
Limitations
- Lower stiffness and heat resistance than PA6 and PA66
- Higher material cost than standard polyamides
- Drying still advised despite low hygroscopicity
- Limited continuous-use temperature for a technical polyamide
Common injection molding defects
- Weld lines — Raise melt temperature and injection speed to better fuse the flow fronts
- Sink marks — On thick sections: increase holding pressure and time
- Warpage — Uneven cooling: homogenize mold temperature regulation
Typical applications
Pneumatic tubing, connectors, cosmetic parts