Melt processible thermoplastic polyolefin blends for car bumpers and other articles and a process for the preparation thereof

摘要

A melt processable thermoplastic blend and a process for the preparation thereof is disclosed. The blend comprises an intimate mixture of polypropylene copolymer, EPDM and other additives and exhibits suitable flow properties as well as mechanical properties (such as melt flow index: 10-15 g/10 minutes; flexural modulus: 8000-15000 kg/cm2; (notched Izod impact strength: 50-60 kg.cm/cm; and heat deflection temperature: 60-105° C.) necessary for injection molding of car bumpers as well as their property requirements. It is prepared by extruding the components in a twin screw extruder or a Buss co-kneader all together or in separate batches, while for example, the twin screw temperature is maintained in the range of 180 to 250° C. and the screws are rotated at a speed of 50 to 100 rpm.