Polypropylene copolymer is a crystalline thermoplastic that starts with polymer grade propylene with 1-7% ethylene monomer added during bulk polymerization. Comonomer content and molecular weight distribution can be controlled in the reactor allowing for a wide range of grades and properties typically noted for the following:
- Chemical Resistance
- Low Temperature Impact Strength
PP copolymer is commonly available in general purpose, glass reinforced and talc/mineral filled grades. Impact strength increases for grades with higher comonomer content, but this also lowers tensile strength and heat deflection temperatures. The 24 hour water absorption rate is less than 0.03% for unreinforced grades so pre-drying is not required. Drawbacks include high mold shrinkage rates (0.012-0.025 in/in), notch sensitivity, limited flammability resistance, and a “waxy” finish.
AGS Technology injection molds cost effective general purpose, glass reinforced, and talc/mineral filled grades of polypropylene copolymer into air management panels, brackets, substrates, battery trays, and many other applications. To reference the product data sheet for general purpose PP copolymer click on Injectoblend FPP135.