🧩 PEEK+PEI – Polyether Ether Ketone + Polyetherimide
(High-performance hybrid material, combining the exceptional thermal and mechanical resistance of PEEK with the dimensional stability and flame retardancy of PEI (Ultem®). Offers thermal stability up to 260 °C.)
🔹 What is PEEK+PEI
PEEK+PEI is a semi-crystalline-amorphous blend, developed to achieve a balance between extreme resistance and processability. PEEK provides the crystalline structure and mechanical strength, while PEI (Ultem®) improves adhesion, dimensional stability, and fire behavior. The result is a high-end technical material with minimal shrinkage and a smooth, professional finish.
🔧 Composition & Properties
- Base: 60–80% PEEK, 20–40% PEI.
- Density: 1.35–1.40 g/cm³.
- Melting Point: ≈ 340 °C.
- Chemical Resistance: Exceptional (oils, fuels, solvents).
- Continuous Heat Resistance: 240–260 °C.
🚗 Where PEEK+PEI is used in the automotive industry
| Component | Example parts | Observations |
| Engine / Thermal | EGR covers, pumps, valves | Extreme rigidity, stable at 250 °C |
| Electrical / Sensors | ECU housings, connector covers | Excellent insulation and heat resistance |
| Transmission | Structural parts, spacers | Resistance to pressure and vibrations |
| Technical Structures | Frames, clips, load-bearing parts | Dimensionally stable and durable |
🔧 Welding Temperature and Methods
| Method | Optimal Temp | Observations |
| Hot Air | 380 – 400 °C | Slow melting, controlled flow |
| Plastic Extrusion | 370 – 400 °C | PEEK or compatible PEI rods |
| Heat Plate (Mirror) | 370 – 390 °C | Clean bond, zero oxidation |
🔩 Material Compatibility
- ✅ Compatible: PEEK, PEI, PPS, PPSU, PES, PSU, PEEK+GF.
- ⚠️ Good Compatibility: PPS+PEI, PPA, PPS+CF.
- ❌ Incompatible: PP, PE, PS, ABS, PC, PET (completely different melting points).
💡 ReplastMD Recommendation: Use PEEK rods at 390 °C. Heat uniformly and slowly; gradual cooling ensures compact joints without internal stresses.
🧠 How to Identify PEEK+PEI
- Engraved marking: >PEEK+PEI<, >VICTREX<, >EXTEM<, >VESTAKEEP<.
- Texture: Matte or semi-glossy, extremely rigid.
- ReplastMD practical test: If the part is rock-solid, heavy, and does not deform under 250 °C hot air, it is confirmed. Burns with a faint ketone/imide scent.
🛠️ PEEK+PEI Welding at ReplastMD:
At our ReplastMD service center (Chisinau, Ciocana sector), we perform professional PEEK+PEI welding for technical housings and pumps, ensuring a dense, durable finish capable of industrial performance.