Fiber pellets method of making, and use in making fiber reinforced polypropylene composites

Abstract

The present disclosure is directed generally to synthetic organic fiber pellets, methods for making such pellets, and methods of using such pellets for making fiber reinforced polypropylene composite resins. The synthetic organic fiber pellets include at least 80 wt % of a synthetic organic fiber chosen from polyalkylene terephthalates, polyalkylene naphthalates, polyamides, polyolefins, polyacrylonitrile, and combinations thereof, and from 2 to 20 wt % of one or more waxes. The synthetic organic fiber pellets are produced using a pelleting press process. Also provided is a method for making fiber reinforced polypropylene composite pellets including feeding into a compounding extruder at least 25 wt % polypropylene based polymer, from 5 to 60 wt % of synthetic organic fiber in the form of the synthetic organic fiber pellets, and from 0 to 60 wt % inorganic filler; extruding the polypropylene based resin, the fiber pellets, and the inorganic filler through the compounding extruder to form a fiber reinforced polypropylene composite melt; cooling the fiber reinforced polypropylene composite melt to form a solid fiber reinforced polypropylene composite; and pelletizing the solid fiber reinforced polypropylene composite to form fiber reinforced polypropylene composite pellets; wherein an article molded from the composite pellets has a flexural modulus of at least 2.07 GPa and exhibits ductility during instrumented impact testing. Articles molded from the fiber reinforced polypropylene composite pellets find application as automotive parts, household appliance parts, or boat hulls.