🧩 PS-GP – General Purpose Polystyrene
(Rigid, transparent or opaque material with a glossy appearance and high dimensional stability. Used in automotive interior caps, frames, grilles, and components where impact requirements are low.)
🔹 What is PS-GP
PS-GP (General Purpose Polystyrene) is the standard and pure form of polystyrene (PS), without impact modifiers.
It is an amorphous thermoplastic based exclusively on styrene, characterized by transparency, rigidity, and a glossy surface. It is easily processed via injection molding and thermoforming but is brittle under shock, which is why it is used in aesthetic applications not exposed to mechanical stress.
🔧 Composition
- Styrene Monomer ($C_8H_8$) – 100 %
- Density: 1.04–1.06 g/cm³
- Melting Point: ≈ 200–210 °C
- Shore D Hardness: 70–80
- Type: Amorphous, unmodified polymer (GPPS)
🚗 Where PS-GP is used in the automotive industry
| Component | Example parts | Observations |
| Car Interior | Caps, frames, buttons, speakers | Glossy, decorative surface |
| Console / Dashboard | Rigid inserts, panels | Lightweight, dimensionally stable |
| Caps / Grilles | Aesthetic elements, logos | Can be painted and engraved |
| DIY / Tuning | Custom housings, LED frames | Easily processed and thermoformed |
🔧 Welding Temperature and Methods
| Method | Optimal Temperature | Observations |
| Hot Air | 220 – 240 °C | Welding possible, watch for overheating |
| Heat Plate (Mirror) | 210 – 230 °C | Aesthetic joint, risk of warping |
| Manual Extrusion | 200 – 220 °C | Possible on thin sections |
🔩 What to Weld PS-GP With (Material Compatibility)
PS-GP, being a pure styrenic material, welds only with materials from the styrenic family – namely PS, HIPS, SAN, and ABS.
✅ Compatible:
- PS-GP ↔ PS-GP / PS-HI / HIPS – ideal combination.
- PS-GP ↔ SAN / ABS – partially compatible.
❌ Incompatible:
- PP, PE, TPO, PA, PC – completely different melting points.
💡 ReplastMD Recommendation:
Use PS or HIPS rods at a temperature of 230–240 °C with moderate air flow. Heat uniformly and avoid excessive pressure — PS-GP is brittle. After welding, you can apply local polishing to restore the gloss.
🏭 Manufacturers and Trade Names
- INEOS Styrolution: Styron® GPPS
- BASF: Polystyrol® GP
- TotalEnergies: Crystal PS®
- SABIC: General Purpose PS
🧠 How to Identify PS-GP
- Engraved marking: >PS-GP<, >GPPS<, >PS-C<, >PS-CLEAR<.
- Glossy, rigid surface, transparent or milky-white.
- Yellow-blue flame, sweetish (styrenic) smell.
- Softens at ≈ 220 °C, melts cleanly.
- When breaking, it produces a sharp sound and sharp edges.
🛠️ PS-GP Welding at ReplastMD:
At our service center in Chisinau (Ciocana sector), ReplastMD performs PS-GP welding for:
- decorative caps, frames, and inserts;
- aesthetic parts and interior panels;
- restoring broken mounts and fine repairs.