摘要:
The present invention provides a process for preparing high melt strength propylene polymer by direct polymerization, comprising that a propylene polymer with wide molecular weight distribution and containing “very high molecular weight fraction” can be prepared by controlling the species and ratios of the external electron donors in the Ziegler-Natta catalyst system at different reaction stages according to the requirement for different molecular weight fractions in the different propylene polymerization stage of the series operation, and said polymer has excellent mechanical properties, especially with very high melt strength. The present invention also provides a propylene homopolymer with high melt strength, comprising the following features: (1) the MFR is 0.2-10 g/10 min at 230° C. with a load of 2.16 kg; (2) the molecular weight distribution Mw/Mn is 6-20; (3) the content of the fraction with a molecular weight higher than 5,000,000 is higher than or equal to 0.8 wt %; (4) Mz+1/Mn is higher than or equal to 70. Said homopolymer can be used in the preparation of foam products, thermoforming products, biaxial stretching films, blown films and blow-molded products.
摘要:
The present invention provides a process for preparing high melt strength propylene polymer by direct polymerization, comprising that a propylene polymer with wide molecular weight distribution and containing “very high molecular weight fraction” can be prepared by controlling the species and ratios of the external electron donors in the Ziegler-Natta catalyst system at different reaction stages according to the requirment for different molecular weight fractions in the different propylene polymerization stage of the series operation, and said polymer has excellent mechnical properties, especially with very high melt strength. The present invention also provides a propylene homopolymer with high melt strength, comprising the following features: (1) the MFR is 0.2-10 g/10 min at 230° C. with a load of 2.16 kg; (2) the molecular weight distribution Mw/Mn is 6-20; (3) the content of the fraction with a molecular weight higher than 5,000,000 is higher than or equal to 0.8 wt %; (4) Mz+1/Mn is higher than or equal to 70. Said homopolymer can be used in the preparation of foam products, thermoforming products, biaxial stretching films, blown films and blow-molded products.
摘要:
The invention discloses a process for preparing high-performance propylene polymers, the process utilizing a high activity, highly stereoselective Ziegler-Natta catalyst and two or more stages of polymerization carried out under different hydrogen concentrations to prepare propylene polymers having broad molecular weight distribution, wherein non-unifomess of isotacticity of molecular chains of the final propylene polymers is improved by adjusting or controlling stereoselectivity of catalytic active sites under different hydrogen concentrations, namely, making the low molecular weight fraction of the polymers having a higher isotacticity and making the high molecular weight fraction of the polymers having a lower isotacticity, thereby overcoming the drawbacks of the propylene polymers having broad molecular weight distribution known in the art. The resulting final polymers have excellent combined properties, in particular, remarkably improved mechanical properties.
摘要:
The present invention provides a propylene polymer composition for producing a biaxially oriented film, comprising propylene random copolymer and propylene homopolymer; wherein the propylene random copolymer is a copolymer of propylene and ethylene, optionally comprising one or more alpha-olefins of C4-C10; the propylene polymer composition has an overall isotacticity index, as determined by nuclear magnetic resonance method, of greater than or equal to 96.5%, and an ethylene content of greater than 0.3 wt %; and wherein, the melt flow rate of the propylene random copolymer is lower than that of the propylene homopolymer. The biaxially oriented polypropylene film produced by the propylene polymer composition of the present invention exhibits excellent physical properties, and has, in the absence of any stiffening agent, relatively higher modulus and stiffness. Moreover, the process for producing the biaxially oriented polypropylene film is featured with a good film-forming stability and a high film-forming stretching speed.
摘要:
The present invention provides a propylene polymer composition for producing a biaxially oriented film, comprising propylene random copolymer and propylene homopolymer; wherein the propylene random copolymer is a copolymer of propylene and ethylene, optionally comprising one or more alpha-olefins of C4-C10; the propylene polymer composition has an overall isotacticity index, as determined by nuclear magnetic resonance method, of greater than or equal to 96.5%, and an ethylene content of greater than 0.3 wt %; and wherein, the melt flow rate of the propylene random copolymer is lower than that of the propylene homopolymer. The biaxially oriented polypropylene film produced by the propylene polymer composition of the present invention exhibits excellent physical properties, and has, in the absence of any stiffening agent, relatively higher modulus and stiffness. Moreover, the process for producing the biaxially oriented polypropylene film is featured with a good film-forming stability and a high film-forming stretching speed.
摘要:
The present invention relates to a catalyst component and a catalyst for olefin polymerization. The catalyst component utilizes magnesium halide and silica as composite support, and the particle morphology thereof can be improved by regulating the ratio of magnesium halide to silica. Further, the purpose of stabilizing the rate of catalytic polymerization reaction and improving the particle morphology of polymer so as to meet the requirements on catalyst performance of various polymerization processes can be achieved through the combination of the supports of the catalyst. In the meantime, when used in the polymerization of propylene, the catalyst of the present invention exhibits a relatively high polymerization activity and high stereospecificity.
摘要:
The present invention relates to a catalyst component and a catalyst for olefin polymerization. The catalyst component utilizes magnesium halide and silica as composite support, and the particle morphology thereof can be improved by regulating the ratio of magnesium halide to silica. Further, the purpose of stabilizing the rate of catalytic polymerization reaction and improving the particle morphology of polymer so as to meet the requirements on catalyst performance of various polymerization processes can be achieved through the combination of the supports of the catalyst. In the meantime, when used in the polymerization of propylene, the catalyst of the present invention exhibits a relatively high polymerization activity and high stereospecificity.
摘要:
A catalyst component for the (co)polymerization of olefins is provided. The catalyst comprises titanium, magnesium halogen and a mixed electron-donor and a catalyst for the (co)polymerization of olefins comprising:(A) the catalyst component; (B) an organic aluminum compound; and (C) an organic silicon compound. A polymer with high and adjustable stereospecificity and broad molecular weight distribution can be prepared by using the catalyst.
摘要:
A catalyst for the polymerization of propylene comprising components (A), (B) and (C) is provided. Component (A) is a solid product prepared by dissolving a halide of magnesium in a solvent system consisting of an organic epoxy compound, an organic phosphorus compound and an inert diluent to form a homogeneous solution; mixing the homogeneous solution with a halide of titanium to form a mixture; precipitating a solid from the mixture in the presence of an auxiliary precipitant; treating the solid with a polycarboxylic ester to load the ester on the solid; and treating the ester loaded solid with the halide of titanium and the inert diluent. Component (B) is an organic aluminium compound, and component (C) is an organic silicon compound. The particle size of the catalyst can be adjusted by increasing the amount of the inert diluent at a low ratio of the epoxy compound to the phosphorus compound.