| 摘要 |
PURPOSE:To obtain a polypropylen for a biaxially oriented film which has a good stretchability and gives a film excellent in transparency and stiffness by using a specific catalyst system to impart specified properties to polypropylene. CONSTITUTION:This polypropylene which has a decalin-sols. content at 23 deg.C of 3.0-10.0wt.% and a melt flow rate at 230 deg.C of 0.5-10.0g/10min and exhibits a complex modulus under vibration at 110Hz of 1.0X10<9>-dyn/cm<2> in a temp. range of 134-152 deg.C is obtd. by using a catalyst system comprising a solid catalyst component (A) contg. Mg, Ti, a halogen, and an electron donor as the essential components, an organoaluminum compd. (B), and at least two electron donors (C) of which one, when used together with components A and B, gives a propylene homopolymer having a disorder index of the xylene-insol. part at 105 deg.C satisfying 0<=mmrr/mmmm<=0. 0068 and the other gives the homopolymer having that satisfying 0.0068<mmrr/mmmm<=0.0320. |
