HIPS 8350 is a very high impact polystyrene designed for extrusion sheets, providing improved Environmental Stress Cracking Resistance (ESCR) compared to other standard high impact polystyrenes such as HIPS 7240. The superior melt strength of HIPS 8350 makes it especially suitable for deep-draw thermoforming applications. This grade is recommended for packaging that comes into contact with substances likely to cause stress cracking, such as fats and oils.
 
Key Features
Improved ESCR: Enhances durability and resistance to stress cracking, ideal for packaging applications involving aggressive substances.
Excellent Melt Strength: Facilitates deep-draw thermoforming, allowing for the creation of complex shapes and deep-drawn parts.
Food Contact Approval: Certified safe for use in food packaging, suitable for frozen food packaging and for use in fridge liners.
 
Applications
Thermoforming: Used extensively in the production of deep-drawn parts.
Fridge Doors and Cabinet Liners: Ideal for components within refrigeration units.
Packaging for Fatty Foods: Specifically designed to resist stress cracking when in contact with oils and fats.
 
Typical Properties
Melt Flow Index (200°C/5kg): 4.5 g/10 min (ASTM D-1238), indicating the flowability of the material under heat.
Styrene Residual Monomer: <500 ppm (CLG LABPSG004), ensuring low residual content for safety.
Vicat Softening Point: 96°C (ASTM D-1525), the temperature at which the polymer begins to soften.
Rockwell Hardness: Scale/R54 (ISO 2039-2), measuring the surface hardness of the material.
Tensile Stress at Yield: 18 MPa (ISO 527-2), indicating the stress at which the material begins to deform.
Tensile Stress at Break: 20 MPa (ISO 527-2), showing the material's maximum stress capacity before breaking.
Elongation at Break: 60% (ISO 527-2), indicating the flexibility of the material.
Tensile Modulus: 1600 MPa (ISO 527-2), reflecting the stiffness of the material.
Izod Impact: 13 KJ/m2 (ISO 180/1A), demonstrating the material's resistance to impact at room temperature.
 
Conclusion
HIPS 8350 is engineered for applications requiring a material with high impact resistance, excellent thermoformability, and improved stress cracking resistance. Its suitability for food contact makes it an excellent choice for the food packaging industry, particularly for packaging designs involving cold temperatures and potential chemical interactions.