| 摘要 |
PURPOSE:To obtain the title polymer composition for packaging materials of outstanding transparency and resistance to impact and heat, by polymerization of propylene using a catalyst consisting of a transition metal catalytic component and a halogen- contg. organoaluminum compound followed by copolymerization between ethylene and the rest of the propylene in the presence of an additional halogen-free organoaluminum compound. CONSTITUTION:In the first step, propylene is polymerized using a catalyst consisting of a transition metal catalytic component and an organoaluminium compound of formula I (R<1> is 1-10C alkyl, 6-12C aryl, etc.; X is halogen; 0<n<=2) to produce a propylene homopolymer 1.0-5.0dl/g in intrinsic viscosity [eta]p and >=94% in isotactic pendant fraction so as to account for 60-95wt.% of the whole polymer. In the second step, a second organoaluminum compound of formula II (R<2> is 1-10C alkyl, 6-12C aryl, etc.; 0<m<=3) is added to the system in an proportion of 0.02-3mols per mol of the compound of the formula I and a copolymerization is carried out between ethylene and the rest of the propylene to produce a propylene-ethylene random copolymer 10-80wt.% in ethylene content, satisfying the relationship III for its intrinsic viscosity [eta]Ep so as to account for 40-5wt.% of the whole polymer, thus obtaining the objective polymer composition. |
