🧩 PS-HI – High Impact Polystyrene (HIPS)
(Rigid yet shock-resistant material with a glossy and slightly matte surface. Frequently used in automotive interior caps, housings, frames, and components requiring aesthetic appeal and enhanced mechanical resistance compared to PS-GP.)
🔹 What is PS-HI
PS-HI (High Impact Polystyrene) is a polystyrene modified with butadiene rubber, obtained through the copolymerization of styrene ($C_8H_8$) with butadiene ($C_4H_6$).
This modification grants it elasticity, impact resistance, and crack resistance while maintaining the glossy appearance and rigidity of classic PS. PS-HI is the core material for many interior automotive components and electrical housings, serving as an economical alternative to ABS.
🔧 Composition
- Styrene ($C_8H_8$) – 85–95 %
- Butadiene ($C_4H_6$) – 5–15 % (rubber phase)
- Additives – UV stabilizers, colorants, antioxidants.
- Density: 1.03–1.06 g/cm³
- Melting Point: ≈ 200–220 °C
- Impact Resistance: up to 10× higher than PS-GP.
🚗 Where PS-HI is used in the automotive industry
| Component | Example parts | Observations |
| Car Interior | Panels, caps, consoles, frames | Glossy, rigid, yet shock-resistant |
| Light Exterior | Mirror covers, guards | Easily paintable |
| Electrical | Sensor housings, brackets | Insulating and aesthetic |
| Tuning / DIY | Decorative inserts | Can be thermoformed and polished |
🔧 Welding Temperature and Methods
| Method | Optimal Temperature | Observations |
| Hot Air | 230 – 250 °C | Clean weld, uniform melting |
| Heat Plate (Mirror) | 220 – 240 °C | Aesthetic, controlled joint |
| Manual Extrusion | 210 – 230 °C | Suitable for small thicknesses |
🔩 What to Weld PS-HI With (Material Compatibility)
Since it is a modified styrenic material, PS-HI is compatible with PS, ABS, and SAN due to the common styrene base.
✅ Compatible:
- PS-HI ↔ PS-HI / HIPS / PS-GP – ideal combination.
- PS-HI ↔ ABS / SAN / ASA – good compatibility (depending on styrene proportion).
❌ Incompatible:
- PP, PE, TPO, PA, PC – different structures and melting points.
💡 ReplastMD Recommendation:
Use PS-HI or ABS rods at a temperature of 240–250 °C. Maintain uniform heating and low pressure to avoid excessive gloss and warping. You can later finish with fine sandpaper and polish to restore the original appearance.
🏭 Manufacturers and Trade Names
- INEOS Styrolution: Styrolux®, Terluran® HI
- BASF: Polystyrol® HI
- TotalEnergies: High Impact PS®
- SABIC: PS-HI Resin
🧠 How to Identify PS-HI
- Engraved marking: >PS-HI<, >HIPS<, >PS-IMPACT<, >HI-PS<.
- Glossy, but slightly matte compared to PS-GP.
- Yellow-blue flame, sweetish (styrenic) smell.
- Softens at ≈ 240 °C without bubbling.
- Slightly elastic under pressure, does not crack immediately when bent.
🛠️ PS-HI Welding at ReplastMD:
At our service center in Chisinau (Ciocana sector), ReplastMD performs professional PS-HI welding for caps, frames, consoles, and interior panels, ensuring invisible joints and durable structural restoration.