🧩 POM-C – Polyoxymethylene Copolymer (Acetal Copolymer)
(A variant of POM with superior thermal and chemical stability, known under trade names such as Hostaform®, Ultraform®, or Kepital®. POM-C offers better processability, higher chemical resistance, and a reduced tendency to stress cracking.)
🔹 What is POM-C
POM-C (acetal copolymer) differs from POM-H (homopolymer) by having additional oxygen units in the molecular chains. This reduces crystallinity, making it easier to process, more resistant to hydrolysis and chemicals, and less brittle at low temperatures. In the automotive industry, POM-C is preferred for valves, pumping parts, and connectors where frequent contact with technical fluids is expected.
🔧 Composition & Properties
- Base: Formaldehyde units modified with oxygen comonomers.
- Density: 1.41–1.43 g/cm³.
- Melting Point: ≈ 165–172 °C.
- Chemical Resistance: Excellent (oils, fuels, solvents, hot water).
- Continuous Heat Resistance: 100–110 °C.
🚗 Where POM-C is used in the automotive industry
| Component | Example parts | Observations |
| Moving Mechanisms | Gears, bearings, cams | Low friction, high wear resistance |
| Fasteners / Clips | Clips, hinges, latches | Elasticity without stress cracking |
| Fluid Systems | Valves, connectors, pumps | Resists antifreeze, oils, and hot water |
| Technical Housings | Supports, bearings | Chemical and dimensional stability |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 250 – 270 °C | Fast melting, controlled airflow required |
| Plastic Extrusion | 240 – 260 °C | Ideal for thick and technical parts |
| Heat Plate (Mirror) | 240 – 260 °C | Smooth and clean bonding |
🔩 Material Compatibility
- ✅ Compatible: POM-C, POM-H, Hostaform®, Ultraform®, Kepital®.
- ❌ Incompatible: PA, PP, PE, PVC, ABS, PC (completely different melting points).
💡 ReplastMD Recommendation: Use POM-C or Hostaform® rods at 260 °C. Thoroughly clean the surface as residue affects bonding. Avoid overheating—POM releases formaldehyde vapors above 270 °C.
🧠 How to Identify POM-C
- Engraved marking: >POM-C<, >ACETAL<, >HOSTAFORM<, >ULTRAFORM<.
- Texture: Glossy, dense, with a “cold” feel to the touch.
- ReplastMD practical test: Does not absorb water. Burns with a blue flame and a sharp formaldehyde scent. Softens at ≈ 170 °C.
🛠️ POM-C Welding at ReplastMD: At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional POM-C welding for fluid system valves and precision mechanisms, ensuring a durable, chemical-resistant finish.