IN-LINE COMPOUNDING AND MOLDING PROCESS FOR MAKING FIBER REINFORCED POLYPROPYLENE COMPOSITES

摘要

The present invention is directed to an in-line compounding and molding process for making fiber reinforced polypropylene composite parts and articles that exhibit beneficial mechanical and aesthetic properties imparted by such process and compositions. The in-line compounding and molding process includes the steps of providing an in-line compounding and molding machine comprising a twin screw extruder fluidly coupled to an injection molder; extrusion compounding in the twin screw extruder a composition comprising at least 30 wt% polypropylene, from 10 to 60 wt% organic fiber, from 0 to 40 wt% inorganic filler, and from 0 to 0.1 wt% lubricant to form a melt extrudate; conveying the melt extrudate to the injection molder; and molding the melt extrudate in the injection molder to form a part or article. Fiber reinforced polypropylene articles formed from the in-line compounding and molding process have flexural modulus of at least 300,000 psi and exhibit ductility during instrumented impact testing. Fiber reinforced polypropylene articles formed from the process of the present invention are particularly suitable for making household appliances, automotive parts, and boat hulls.