Catalytic system containing phosphate external electron donors for polypropylene polymerization and application of catalytic system

Abstract

The invention provides a catalytic system containing phosphate external electron donors for polypropylene polymerization. The catalytic system is prepared from a solid catalyst component (A), alkyl aluminum (B) and a multicomponent external electron donor (C), wherein the component (A) is a magnesium halide-supported Ti solid component and contains diester internal electron donors, diether internal electron donors or a combination of the donors; the component (C) comprises a first type of external electron donors and a second type of external electron donors; the first type of the external electron donors are silane which at least contains one alkoxy of C1 to C10; the second type of the external electron donors are selected from one or more of phosphate compounds or phosphonate compounds. When the catalytic system is used for olefin polymerization, the catalytic system can realize the characteristic of inhibiting high-temperature activity of a catalyst; in addition, the effect of the catalytic system is no-less-favorable than a temperature control effect of fatty acid ester compounds in the prior art.

Description

technical field [0001] The invention relates to a catalytic system for olefin polymerization, in particular to a catalytic system for olefin polymerization containing a phosphate external electron donor and / or a phosphonate external electron donor and its application. Background technique [0002] Catalytic systems for Ziegler-Natta propylene polymerization are well known in the art. Generally, the catalytic system includes a main catalyst, an internal electron donor, an aluminum alkyl and an external electron donor. [0003] Among them, the internal electron donor is indispensable as a component in the catalytic system, and with the development of the internal electron donor compound, it has led to the continuous updating of the catalytic system for polyolefins, especially polypropylene. At present, a large number of published A variety of internal electron donor compounds, such as polycarboxylic acids, monocarboxylic acid esters or polycarboxylic acid esters, acid anhydri...

AI Technical Summary

Problems solved by technology

However, propylene polymerization is a violent exothermic reaction, and temperature control is very important. If the temperature is too high, it may cause sudden polymerization, blockage of the reactor, and shutdown.

In the polymerization reaction, an increase in temperature often leads to an increase in the polymerization rate and a further increase in the heat release, which often results in a rapid temperature rise and brings difficulties to the control of the reactor.

The current siloxane-based external electron donors cannot control the temperature adjustment during the polymerization process. Therefore, people want to adjust the temperature during the polymerization process by adding a second type of external electron donor to control the smooth progress of the polymerization reaction.

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