While they may look similar on a spec sheet, their chemical structures behave very differently under stress, heat, and moisture. In this guide, we break down the engineering differences to help you avoid system failure.
1. Working Pressure & Rigidity
PA12 is a rigid semi-crystalline polymer, giving it superior burst pressure capabilities compared to the elastomeric nature of PU. This makes PA12 the preferred choice for main air supply lines, while PU serves best in “last-mile” connections to actuators.
| Specification | PA12 (Nylon) | Polyurethane (PU) |
|---|---|---|
| Max Pressure (20°C) | Up to 44 Bar (High) | ~10-12 Bar (Standard) |
| Temp Range | -40°C to +80°C | -20°C to +60°C |
2. The “Rot” Factor: Hydrolysis
One of the biggest causes of pneumatic failure in tropical climates is hydrolysis—where water molecules break down the polymer chains. Standard Polyester-based PU tubing will effectively “rot” and crack if exposed to high humidity over time.
HBG PA12 is naturally hydrolysis resistant due to its chemical structure. It absorbs less than 1.5% moisture, ensuring dimensional stability even in wet environments or wash-down zones.
3. UV Resistance & Outdoor Use
If your machinery is outside (e.g., agricultural equipment or truck air brakes), UV radiation from the sun will destroy standard PU tubing within months. The material becomes brittle, yellows, and shatters under pressure.
For outdoor applications, Black PA12 is the industry standard. Carbon black is added during extrusion to act as a UV stabilizer, extending the lifespan of the tube to 10+ years outdoors.
Final Verdict
Choose PA12 if: You need high pressure, outdoor durability, chemical resistance, or long runs where tube sagging needs to be minimized.
Choose PU if: You are wiring inside a cabinet, need extreme flexibility for a robotic arm, or require a tight bend radius without kinking.