THERMOPLASTIC POLYMER COMPOSITION AND METHOD OF MOLDING PARTS WITH REDUCED SHRINKAGE

摘要

A thermoplastic polymer composition incorporating at least about 50 wt.%polypropylene, at least about 20 wt.% of an elastomersuch as EP rubber and at least about 4 wt.% plastomer. The plastomer ispreferably a single site catalyzed ethylene based copolymerhaving a density less than about .915 g/cm3. By adjusting the amount of theplastomer in the composition, considerable control is securedover post-mold shrinkage of components produced through injection moldingoperations utilizing the composition. The composition can beprepared as a reactor blend or a melt blend. The composition is particularlyuseful in producing large components such as bumpers andexterior trim fascia for automobiles.