🧩 PA+PBT – Polyamide + Polybutylene Terephthalate
(High-performance technical blend combining the toughness and chemical resistance of polyamide with the dimensional stability and rigidity of PBT. Used in technical housings, connectors, and structural parts where resistance to heat, vibration, and fuel contact is required.)
🔹 What is PA+PBT
PA+PBT is a compatibilized blend between polyamide (PA) and polybutylene terephthalate (PBT). PBT reduces the shrinkage and water absorption of the polyamide, resulting in a rigid, stable, and easy-to-process material. It is widely used in the automotive industry, especially for under-the-hood parts and electrical systems exposed to thermal variations and chemicals.
🔧 Composition
- Polyamide (PA6 / PA66): 50–70 %
- PBT: 30–50 %
- Additives: compatibilizers, thermal/UV stabilizers, glass fibers (optional).
- Density: 1.20–1.35 g/cm³.
- Melting Point: ≈ 250–265 °C.
- Chemical Resistance: Excellent (oils, fuels, antifreeze).
- Continuous Heat Resistance: 120–140 °C.
🚗 Where PA+PBT is used in the automotive industry
| Component | Example parts | Observations |
| Engine / Technical | Covers, sensor housings, mounts | Heat and vibration resistance |
| Electrical / Connect. | Plugs, ECU housings, guides | Dimensional stability and insulation |
| Technical Interior | Frames, covers, functional parts | Low shrinkage, matte finish |
| Protected Exterior | Under-hood functional parts | High chemical and mechanical resistance |
🔧 Welding Temperature and Methods
| Method | Optimal Temperature | Observations |
| Hot Air | 250 – 270 °C | Stable melting, moderate airflow control |
| Heat Plate (Mirror) | 240 – 260 °C | Clean and solid joint |
| Manual Extrusion | 240 – 260 °C | Suitable for thick parts or housings |
🔩 What to Weld PA+PBT With (Material Compatibility)
Compatibility is very good with PA and PBT-based blends, as well as PC+PBT compounds.
✅ Compatible with:
- PA+PBT ↔ PA6 / PA66 / PA+GF / PC+PBT / PBT+ASA – excellent.
- PA+PBT ↔ PA+MD / PA+FR – very good bond.
- PA+PBT ↔ PA+ABS / PA+PPO – partially compatible.
❌ Incompatible with:
- PP, PE, PVC, PS, pure ASA – different melting points.
💡 ReplastMD Recommendation:
Use PA+PBT or PC+PBT rods (Xenoy®, Bayblend®) at 260 °C. Heat uniformly — PBT melts quickly and can flow excessively. Slow cooling ensures a dense, crack-free joint.
🏭 Manufacturers and Trade Names
- SABIC: Xenoy®
- BASF: Ultramid® / Ultradur® Blend
- Covestro: Bayblend® PBT/PA
- DuPont: Crastin® PA/PBT
🧠 How to Identify PA+PBT
- Engraved marking: >PA+PBT<, >PA/PBT<, >Xenoy<, >Ultramid<.
- Semi-glossy surface, dense, rigid.
- Usually dark grey or black (common for OEM parts).
- Blue flame, faint nylon smell.
- Softens at ≈ 260 °C without bubbling.
- ReplastMD practical test: If the part is rigid, has a semi-glossy finish, and is marked >PA+PBT<, it is confirmed Polyamide + PBT.
🛠️ PA+PBT Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PA+PBT welding for sensor covers and electrical connectors, ensuring a clean, dense, and solid finish.