🧩 PTT – Polytrimethylene Terephthalate
(A modern technical polyester, similar to PBT and PET, but with a superior balance between flexibility, strength, and thermal stability. PTT combines the chemical resistance of PET with the moderate elasticity required for vibration-prone components.)
🔹 What is PTT
PTT (Polytrimethylene Terephthalate) is a semi-crystalline thermoplastic polyester. Compared to PBT and PET, PTT offers a lower melting point, higher inherent elasticity, and very low water absorption. In the automotive industry, it serves as a modern alternative for electrical housings, sensor covers, and structural parts that must resist oils and fuels while maintaining some degree of resilience.
🔧 Composition & Properties
- Base: 100 % Polytrimethylene Terephthalate.
- Density: 1.28–1.33 g/cm³.
- Melting Point: ≈ 225–230 °C.
- Chemical Resistance: Excellent (oils, fuels, solvents).
- Continuous Heat Resistance: 100–130 °C.
🚗 Where PTT is used in the automotive industry
| Component | Example parts | Observations |
| Electrical Systems | Connector housings, mounts | Good insulator, oil resistant |
| Engine Bay | Sensor covers, rigid parts | Superior chemical resistance |
| Technical Interior | Frames, guides, aesthetic trim | High gloss, dimensionally stable |
| Eco-friendly OEM | Lightweight components | Performance + sustainability |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 250 – 270 °C | Easy, uniform melting |
| Plastic Extrusion | 240 – 260 °C | Suitable for thick technical parts |
| Heat Plate (Mirror) | 240 – 260 °C | Clean bonding, zero bubbles |
🔩 Material Compatibility
- ✅ Compatible: PBT, PET, PBT+GF, PBT+PC, PBT+PET.
- ⚠️ Good Compatibility: PBT+ASA, PC+PBT, POM+PBT.
- ❌ Incompatible: PP, PE, PS, ABS, PVC, PA (completely different melting points).
💡 ReplastMD Recommendation: Use PBT or PET rods at 260 °C. Heat the area uniformly and avoid direct flame—the material might become matte if overheated.
🧠 How to Identify PTT
- Engraved marking: >PTT<, >SORONA<, >CORTERRA<, >ARNITEL<.
- Texture: Smooth, glossy, and slightly elastic.
- ReplastMD practical test: If the part is rigid but slightly resilient, with a uniform gloss and a PTT mark, it is confirmed. Burns with a sweet ester scent.
🛠️ PTT Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PTT welding for technical housings and frames, ensuring a high-strength, glossy, and factory-grade finish.