🧩 PVC-U – Rigid Polyvinyl Chloride
(Hard and resistant thermoplastic, free of plasticizers, characterized by superior dimensional stability and rigidity. PVC-U is the unplasticized form of PVC used in structural automotive parts and technical housings.)
🔹 What is PVC-U
PVC-U (Unplasticized Polyvinyl Chloride) is pure PVC, making it much stiffer, denser, and more durable than flexible PVC-P. It is the material of choice for technical housings or structural elements that must endure mechanical stress and chemical exposure. Being naturally flame-retardant and UV-stable, it remains a standard in the automotive and electrical industries for pipes and precision parts.
🔧 Composition & Properties
- Base: 100% Polyvinyl Chloride (no plasticizers).
- Density: 1.38–1.45 g/cm³.
- Softening Temperature: 85–95 °C.
- Chemical Resistance: Excellent (acids, bases, salts).
- Continuous Heat Resistance: 60–80 °C.
🚗 Where PVC-U is used in the automotive industry
| Component | Example parts | Observations |
| Housings / Covers | Sensor covers, fuse boxes | Rigid, good electrical insulation |
| Pipes / Fittings | Tubes, elbows, valves, connectors | Chemical resistance and rigidity |
| Panels / Protection | Plates, separators, cable guards | UV stable, hard surface |
| Exterior Elements | Frames, grilles, mudflaps | Resists sun and moderate impacts |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 230 – 250 °C | Clean weld, stable flow |
| Heat Plate (Mirror) | 220 – 240 °C | Smooth bond, no deformation |
| Plastic Extrusion | 230 – 250 °C | Compatible PVC-U rods |
| Solvent Welding | — | Possible with THF or PVC adhesive |
🔩 Material Compatibility
- ✅ Compatible: PVC-U, PVC-P, ABS, ASA – Good.
- ⚠️ Good Compatibility: SAN, PC – Partial.
- ❌ Incompatible: PP, PE, PA, POM, PTFE, PVDF – completely different melting points.
💡 ReplastMD Recommendation: Use PVC-U rods at ≈ 240 °C. Maintain constant hot air and avoid browning the surface. Work in a ventilated space as PVC-U releases chlorinated vapors when overheated.
🧠 How to Identify PVC-U
- Engraved marking: >PVC-U<, >VINYL RIGID<, >GEON<, >INOVYN<.
- Texture: Glossy, hard, slightly brittle.
- ReplastMD practical test: Burns with a yellow-green flame, white smoke, and chlorine smell. Softens slowly at ≈ 90 °C. Rigid and snaps cleanly upon high impact.
🛠️ PVC-U Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PVC-U (rigid) welding for pipes, technical housings, and plates, ensuring a solid, chemical-resistant finish.