Meaning
Thermoplastic resin produced by polymerizing propylene with ethylene to enhance impact resistance at low temperatures. Injection moulders select this material for demanding applications like automotive parts and housewares where toughness is required. This resin is available in both block and random configurations.
Elastomeric Phase
This material achieves high impact strength through the incorporation of an ethylene-propylene rubber phase within the homopolymer matrix. These rubbery domains act as impact modifiers that absorb mechanical energy and prevent crack growth. Sourcing departments choose polypropylene copolymer when the finished parts must survive drop tests or cold-temperature use.
Moulding Parameter
Processing this resin requires optimized cylinder temperatures and screw configurations to ensure proper melting and blending. If the melt is processed at too high a temperature, the polymer can undergo thermal degradation, reducing its mechanical properties. Moulders must monitor and control the injection speed to avoid shear degradation and aesthetic surface defects.
Economic Choice
Choosing copolymer resin is often compared to homopolymer grades, which are cheaper but have lower impact resistance. While the copolymer grade is more expensive, it provides a cost-effective solution for parts that would otherwise require separate elastomer tougheners. This balance makes it a popular choice for high-volume consumer goods and industrial components.
