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 elastomer such as EP rubber and at least about 4 wt.% plastomer. The plastomer is preferably a single site catalyzed ethylene based copolymer having a density less than about .915 g/cm3. By adjusting the amount of the plastomer in the composition, considerable control is secured over post-mold shrinkage of components produced through injection molding operations utilizing the composition. The composition can be prepared as a reactor blend or a melt blend. The composition is particularly useful in producing large components such as bumpers and exterior trim fascia for automobiles.