PS-Chi Mei POLYREX PG-33
PS-Chi Mei POLYREX PG-33 is a general-purpose polystyrene (GPPS) grade manufactured by Chi Mei Corporation, revered for its high optical brightness, standard melt flow (MFI 8.0 g/10 min), and lightweight density of 1.04 g/cm³. Specially formulated for standard injection molding, this grade is the global standard for high-refraction lampshades, transparent food containers, and CD jewel cases. At Jucheng Precision, an ISO 9001 and IATF 16949 certified contract manufacturer, we utilize our 25+ in-house 5-axis CNC machines to cut mirror-polished S136 stainless steel molds. This prevents weld-line defects and relieves residual molding stresses, delivering pristine, stress-free optical components verified by Zeiss CMM inspection.
POLYREX PG-33 Optical Brightness & Toughness Profile
POLYREX® PG-33 is a standard general-purpose polystyrene (GPPS) resin engineered by Chi Mei Corporation, valued for its high refractive index, low density, and high-gloss aesthetics:
| Physical & Optical Property | POLYREX PG-33 Spec Values | Engineering Advantage for Molded Parts |
|---|---|---|
| Optical Refraction | High Refractive High-Brightness Index | Maximizes light transmission and dispersion, preventing internal light loss in complex lampshades and clear display frames. |
| Melt Stability | MFR 8.0 g/10 min (200°C x 5kg) | Provides a stable, predictable flow during continuous production cycles, minimizing gate blush and surface swirl defects. |
| Hardness Stiffness | Ball Indentation Hardness 149 MPa | Ensures a highly rigid structural frame, preventing flexing or dimensional bending in large clear organizer boxes. |
Structural Application & Molding Process Suitability for PG-33
With stable molecular polymerization, Chi Mei POLYREX PG-33 flows uniformly to yield pristine aesthetic finishes:
| Molding Technology | Process Suitability & Operational Details |
|---|---|
| Lampshades & Diffusers | Excellent. Highly suitable for molding geometrically complex transparent lampshades, light guides, and diffusing cover lenses. |
| Transparent Food Containers | Excellent. Fully optimized for high-volume transparent refrigerator crisper drawers, storage canisters, and transparent plastic cups. |
| Cosmetic & Media Enclosures | Excellent. Ideal for crystal-clear cosmetic jar display bases, cassette tape cases, and luxury retail organizers. |
PS-Chi Mei POLYREX PG-33 Tooling & Optical Refraction Guide
Molding an amorphous standard GPPS like POLYREX PG-33 requires careful gating and slow ejection to prevent stress-induced cloudiness and brittle cracking:
- Weld Line & Haze Management: GPPS is highly amorphous, meaning it has low mold shrinkage (0.3% to 0.6%). However, knit lines (weld lines) will block light transmission and degrade optical cosmetics. Jucheng’s tooling division conducts Moldflow analysis to place gates strategically, eliminating visible weld lines in functional view areas.
- Tool Steel Selection & Polishing: To fully leverage PG-33’s high-brightness properties, we use premium S136 stainless steel mold inserts, mirror-polished with high-grade diamond paste. This ensures that the molded components emerge with flawless, glass-like clarity.
- Molding Process Parameters: Process temperatures are managed at 180°C–240°C (356°F–464°F). Mold temperatures are kept at 30°C to 50°C (86°F–122°F). Slower injection speeds and low packing pressures are implemented to prevent residual molding stresses, which would cause birefringence or rainbow effects.
- Precise & Gentle Ejection: Because GPPS is highly rigid and brittle (tensile elongation 2%), sharp ejector pins can crack parts during release. We machine draft angles of at least 1.5° to 2° and utilize wide stripper plates or air-assisted ejection to distribute demolding force evenly.
Key Application Fields for PS-Chi Mei POLYREX PG-33
- Aesthetic Lighting & Optical: High-end geometric ceiling lampshades, transparent LED diffuser covers, and light-guide panels.
- Transparent Food Packing: Refrigerator crisper drawers, stackable plastic food boxes, spice jars, and transparent water tumblers.
- Consumer Goods & Packaging: Clear cassette tape cases, thick-walled cosmetic jar outer display covers, and luxury stationery organizers.
Properties
| Density | 1.04 - 1.05 g/cm³ |
| Melt Mass-Flow Rate (MFR) (200°C/5.0kg) | 8.0 g/10 min |
| Tensile Strength at Yield | 41.0 MPa |
| Tensile Strength at Break | 37.0 MPa |
| Tensile Elongation at Break | 2.0 - 5.0 % |
| Flexural Strength | 62.0 MPa |
| Flexural Modulus | 2,400 MPa |
| Izod Impact Strength (Notched, 23°C) | 2.0 kJ/m² |
| Ball Indentation Hardness | 149 MPa |
| Vicat Softening Point (5.0kg, 50°C/hr) | 89.0 °C |
| Deflection Temperature Under Load (1.8 MPa) | 76.0 °C |
| Flammability Rating (1.6mm) | UL 94 HB - |
| Maximum Part Size | 800 x 600 mm |
| Minimum Part Size | 1 x 1 mm |