🧩 PBT-GF40 – Polybutylene Terephthalate 40% Glass Fiber
(High-performance technical thermoplastic, composed of Polybutylene Terephthalate (PBT) reinforced with 40% glass fiber (GF40). It is one of the most rigid and stable PBT composites, used in structural car parts, housings, and high thermal exposure areas.)
🔹 What is PBT-GF40
PBT-GF40 is a reinforced variant of standard PBT, where the glass fiber content (40%) significantly increases the elastic modulus, tensile strength, and rigidity, while maintaining the excellent chemical resistance characteristic of polyesters.
It is more rigid than PBT-GF20 or PBT-GF30 but also more brittle — making it suitable for technical housings, fixed supports, and parts that require zero elastic deformation.
🔧 Composition
| Component | Typical Proportion | Role |
| PBT | 60 % | Polymer base, chemical resistance, good finish |
| Glass Fiber (GF40) | 40 % | Mechanical reinforcement, rigidity, thermal stability |
| Additives | < 3–5 % | Oxidation protection, stable color, fire safety |
🚗 Where it is used in the automotive industry
| Component | Example parts | Observations |
| Sensor / ECU Housings | Bosch, Valeo, Delphi units | Resistant to 140–160 °C |
| Electrical Connectors | Fine injection parts, fuse blocks | Excellent dielectric properties |
| Engine Bay Parts | EGR covers, coolant pumps | High thermal resistance |
| Interior Mechanics | Guides, fan housings | Low shrinkage, precise shape |
🔩 What to Weld with (Material Compatibility)
- PBT, PBT-GF30, PBT-GF50 ✅ — Good weldability (heat plate, ultrasonic).
- PC+PBT, Xenoy®, Valox® ⚠️ — Partially compatible (requires thermal control).
- PP, PE, PA, PVC, ABS ❌ — Chemically and thermally incompatible.
🏭 Manufacturers and Trade Names
- BASF: Ultradur® B4300G8 / G10
- DuPont: Crastin® B470GF40
- SABIC: Valox® 420GF40
- Celanese: Celanex® 3300GF40
🧠 How to Identify
- Marking:
>PBT-GF40<,>Crastin-GF40<,>Valox-GF40<. - Texture: Dense, rigid, slightly glossy, with visible fiber on broken edges.
- Density: ~1.55–1.60 g/cm³
- ReplastMD practical test: Self-extinguishing flame, faint ester smell, white-grey ash. Extremely rigid — snaps suddenly without plastic deformation.
🛠️ Welding at ReplastMD:
- Heat Plate (Mirror): 250 – 270 °C (Recommended for a precise, tension-free joint).
- Ultrasonic / Vibration: ✅ Ideal (Ensures a solid, vibration-resistant bond).
💡 ReplastMD Recommendation: Welding is performed with controlled hot air or ultrasonic methods, preferably in areas without high mechanical stress. Avoid excessive melting — glass fiber reinforcement can cause micro-cracks if overheated.