HIGHLY CRYSTALLINE POLYPROPYLENE

摘要

A highly crystalline polypropylene characterized by having a crystallinity of not less than 50.5 % as calculated from the heat of melting and satisfying a requirement represented by the formula (II) regarding the relationship between the weight average molecular weight Mw and the proportion f(R) of R-lamellae in spherulites calculated by the following equation (I) from the birefringence DELTA n of the spherulites crystallized by melting the polypropylene at 230 DEG C for 5 min, cooling the melt to 132 DEG C at a temperature fall rate of 20 DEG C/min, and holding the polypropylene at that temperature for 90 min to crystallize the polypropylene. Moldings of this polypropylene or resin compositions comprising the same have excellent rigidity, heat resistance, scratch resistance, and dimensional stability, are less likely to emit odor at the time of molding, and hence can be widely used for various applications. f(R) = (- DELTA n + 0.0351) x 100/0.0528 ... (1), f(R) > -2.5 x (log{Mw} - 4)<2> + 88.9 ... (2)