PP Copolymer
Ethylene added to the propylene chain to buy impact strength, particularly below zero. Block copolymer for toughness, random copolymer for clarity and flexibility.
Two copolymers, two different reasons to use them
Block copolymer carries ethylene in discrete rubbery segments. Those segments absorb impact energy, which keeps a crate or a bumper intact at temperatures where a homopolymer part would crack. Stiffness drops in exchange, and the material is opaque.
Random copolymer distributes a smaller amount of ethylene evenly along the chain. That disrupts crystallinity, lowering the melting point and improving clarity and flexibility. It is the form used for clear containers, medical packaging and pipe.
- Block copolymer grades for crates, automotive and cold-service parts.
- Random copolymer grades for clear packaging and thin-wall containers.
- Impact-modified grades for thin-wall injection at speed.
PP copolymer grades we supply
7 grades are currently available. Availability moves with producer allocation, so confirm the grade with us before you commit a production slot.
- EP 440 G
- EP 440 L
- EP 548 R
- EP 548 T
- RP-345 S
- RP 210 G
- RP 270 G
What decides the copolymer grade
Start with the lowest temperature the part will ever see. That single number usually decides block against random before anything else is discussed.
- Copolymer type: block for cold impact strength, random for clarity and flexibility.
- Ethylene content: more ethylene means more toughness and less stiffness.
- Notched Izod at low temperature: the number that actually predicts field failures.
- Melt flow rate: matched to wall thickness and flow length in the tool.
- Clarifier package: only relevant to random copolymer grades used for clear parts.
Typical copolymer applications
Copolymer earns its premium wherever a part is handled roughly, used cold, or needs to be seen through.
- Crates, bins and returnable transit packaging
- Automotive bumpers and interior trim
- Cold-storage containers and lids
- Battery cases and technical mouldings
- Clear thin-wall food containers
- Medical and pharmaceutical packaging
- Hinged closures and caps
- Blow-moulded bottles and jars
Block or random copolymer for your application?
Tell us the service temperature, whether the part must be transparent, and the moulding process. We will shortlist from there.