Process for preparing creep-resistant atactic polypropylene copolymer

Abstract

A creep-resistant atactic polypropene copolymer with optimized structure and performance is prepared through prepolymerizing catalyst; the catalyst entering the first liquid-phase reactor to contact propylene for polymerization, and then copolymerization by introducing ethylene; the materials after reaction, entering the second tiquid-phase reactor to containus copolymerization under the action of hydrogen, propene and ethyene; the above resultant entering the first gas-phase reactor for copolymerization; then entering the second gas phase reactor for copolymerization; entering a separator and then entering a dryer for final drying to obtain the polypropene powder.

Description

1. Technical field: [0001] The invention is a method for preparing random polypropylene copolymer material, especially a method for optimizing the structure and performance of random copolymer. 2. Background technology: [0002] Like homopolymers, three factors control random copolymers: tacticity, molecular weight, and molecular weight distribution. However, adding comonomers caused more changes. Changes in the production process such as the change of the catalyst, the control of the amount and concentration of the comonomer, these changes determine the final use performance of the product. [0003] According to theoretical calculation, the reactivity ratio r of propylene, ethylene and butene-1 in Z-N type supported catalyst 1 * r 2 >1, its molecular chain distribution should be block copolymerization, and heavier olefin-1, a random copolymer (r 1 * r 2 ≈1). but use 13 C NMR Vibration MgCl 2 The copolymers propylene-ethylene and propylene-butene-1 obtained by t...

AI Technical Summary

Problems solved by technology

For the production process of the liquid slurry method, because ethylene exists in the gas phase in the liquid phase kettle, there are also the problems of comonomer diffusion and dissolution in the liquid phase; and the generated ethylene-propylene copolymer is dissolved in the liquid phase, which will produce Sticky kettle and clogging, its product content is limited below 4m%

For Mitsui Petrochemical's HYPOL process, the difficulty of producing random copolymerization PP is more complicated. It has both gas-phase kettle copolymerization reaction and control, gas-phase copolymerization reaction, and the influence of the previous liquid phase on the subsequent gas-phase reaction, and no The effect of regular copolymers on product sequence distribution and product performance in different reaction systems is more complex.

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