POLYPROPYLENE RESIN AND ITS COMPOSITION.

摘要

A polypropylene resin which has very high rigidity, heat resistance and impact resistance, is well balanced among these properties, and is characterized in that: (1) the content of alpha -olefin units other than propylene is 4 mole % or less, (2) the mmmm fraction in the pentad fraction of the propylene polymer is 96.0 % or above as determined by <1><3>C-NMR spectroscopy, (3) the position (Tmax) of the principal elution peak of the propylene polymer is 118.0 DEG C and the half-value width ( sigma ) of that peak is less than 4.0 degrees as determined by the programmed temperature fractionation method, (4) the intrinsic viscosity [ eta ] of the propylene polymer ranges from 0.5 to 5.0 dl/g, and (5) the rubber component content exceeds 25 % as measured by the pulse NMR method.