| 摘要 |
PURPOSE:To provide the titled composition of great industrial value, with high elongation at breaking having melt flow index exceeding a specific value, also of such molecular weight distribution as to be predominant for high-molecular weight region. CONSTITUTION:The objective composition can be obtained by polymerization, using a catalytic system comprising, as Ti-component, a solid catalytic component prepared, for example, by treatment of a Ti-compound with halogenated hydrocarbon, under such a condition that a polypropylene with high-molecular weight region- predominant molecular weight distribution can be formed. The resulting composition has the following characteristics: (1) melt flow index (MFI) >=10; (2) MW/MN >=6. This ratio can be calculated through the following procedures: first, a molecular weight distribution curve is determined by being subjected to gel permeation chromatography (GPC) followed by expressing the resultant data using rectangular coordinates with ordinate and abscissa representing amount of elution and natural logarithm of molecular weight, respectively; second, with its peak as the center, said curve is divided into three regions, i.e., high, medium, and low molecular weight ones, and furthermore, the high-molecular weight region is approximated with Gaussian distribution.
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