🧩 PBT – Polybutylene Terephthalate
(A semi-crystalline technical thermoplastic from the polyester family, featuring high mechanical strength, stiffness, and dimensional stability, even at high temperatures. Widely used for electrical housings, connectors, and headlight components.)
🔹 What is PBT
PBT (Polybutylene Terephthalate) is a thermoplastic polyester that stands out for its electrical insulation and chemical resistance. Similar to PET but with better processability, it melts uniformly and provides superb dimensional stability. In the automotive world, PBT is the preferred choice for connector housings, sensor supports, and headlight parts because it withstands heat, oils, and electrical stress without warping.
🔧 Composition & Properties
- Base: 100% Aromatic Polyester.
- Density: 1.30–1.35 g/cm³.
- Melting Point: ≈ 220–225 °C.
- Chemical Resistance: Excellent (oils, fuels, solvents).
- Continuous Heat Resistance: 120–150 °C.
🚗 Where PBT is used in the automotive industry
| Component | Example parts | Observations |
| Electrical / Electronics | Connectors, sensor mounts | Excellent insulation, current resistance |
| Engine / Tech Compartment | Covers, supports, guides | High thermal and chemical stability |
| Headlights / Lighting | Housings, LED supports | UV and thermal radiation resistance |
| Technical Interior | Rigid parts, aesthetic trim | Glossy finish, zero visible shrinkage |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 250 – 270 °C | Fast melting, requires thermal control |
| Plastic Extrusion | 240 – 260 °C | Suitable for thick technical parts |
| Heat Plate (Mirror) | 240 – 260 °C | Uniform, smooth bonding |
🔩 Material Compatibility
- ✅ Compatible: PBT, PET, PBT+GF, PBT+PC, PBT+ASA, PBT+PET.
- ⚠️ Good Compatibility: PC+PBT, POM+PBT, PA+PBT.
- ❌ Incompatible: PP, PE, ABS, PMMA, PVC (completely different melting points).
💡 ReplastMD Recommendation: Use PBT or PC+PBT rods at 260 °C. Keep the contact area clean—deposits significantly affect adhesion. Avoid overheating, as polyesters can emit slightly irritating sweet-smelling vapors.
🧠 How to Identify PBT
- Engraved marking: >PBT<, >ULTRADUR<, >VALOX<, >CRASTIN<.
- Texture: Smooth, glossy, and rigid.
- ReplastMD practical test: If the part is rigid, glossy, and slightly brittle when bent, it’s PBT. Burns with a yellow-blue flame and a sweet ester scent.
🛠️ PBT Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PBT / Crastin / Ultradur welding for connector housings and headlight components, ensuring a durable, factory-grade finish.