Catalyst component for ethylene polymerization and catalyst thereof

Abstract

The invention provides a solid catalyst component for ethylene polymerization or copolymerization, which does not adopt silica gel and the like as carriers, but uses a solid containing magnesium and titanium as the carrier component and loads a certain quantity of a titanium compound, an electron donor and an activator, and the catalyst component has the advantages of relatively narrow particle size distribution, high activity of the catalyst and obtainment of a polymer with low content of fine powder, thereby being applicable to slurry polymerization or vapor phase polymerization of ethylene, in particular to the polymerization process of a vapor phase fluidized bed of the ethylene which feeds the catalyst in the slurry form.

Description

technical field [0001] The invention relates to a solid catalyst component for ethylene polymerization or copolymerization, a preparation method thereof, and a catalyst containing the solid catalyst component. technical background [0002] In the polymerization of olefins, especially the polymerization of ethylene or the copolymerization of ethylene and α-olefins, catalyst components based on magnesium, titanium, halogen and electron donors are mostly used. When this type of catalyst is used in a gas-phase fluidized bed polymerization process, in order to ensure that the shape and particle size distribution of the catalyst particles are more suitable for the operation in a fluidized state, the above-mentioned catalyst components are usually supported on a carrier such as silica gel. For example: the catalysts disclosed in US4,302,565, US4,379,759 and CN 1064870A for gas-phase fluidized bed reactions are impregnated with matrix components prepared from titanium compounds, mag...

AI Technical Summary

Problems solved by technology

[0003] In the above-mentioned published patents, in order to make the catalyst applicable to the gas-phase fluidized bed polymerization process, there are relatively strict requirements on the average particle size, surface area, and pore size of the carrier-silicon dioxide used, and the price of this carrier material More expensive, and the silica carrier needs to be strictly activated before use, all of which lead to an increase in the production cost of the catalyst

And because the active components of the catalyst are loaded on the carrier by impregnation and other methods, the catalyst efficiency is not satisfactory due to the limitation of the amount of titanium loaded.

In addition, the amount of fine powder in the polyethylene powder produced by using this catalyst is relatively large, usually the particles below 150 microns account for about 15wt% of the whole powder, which is very undesirable in industrial production

[0004] The catalyst production method mentioned in the Chinese patent CN 1085915A, although overcomes some shortcomings mentioned above, needs to use metal magnesium as a reducing agent in the production process, and still needs to use a large amount of silica carrier substances, and finally needs The method of spray drying is still required to obtain catalyst particle products, which requires large equipment investment and complicated operation, so that the overall production cost is still high

[0005] In the Chinese patent CN85100997, a catalyst for olefin polymerization is disclosed, which is formed by dissolving magnesium halide in organic epoxy compounds and organic phosphorus compounds to form a uniform solution, and then giving it with at least one precipitation aid and a polycarboxylic acid ester. It is prepared by the action of electron bodies and transition metal titanium halides and their derivatives. When the catalyst is used for propylene polymerization, it shows high polymerization activity and good stereospecificity, but when it is used for ethylene polymerization, the activity is low. , and the particle size distribution of the polymer is wide, and the hydrogen adjustment sensitivity of the catalyst is not good

When the catalyst prepared by this process is used in the fluidized bed polymerization process, the reaction activity is high, and the fine powder content of the polymer powder is also greatly reduced, but the catalyst preparation process is long and complicated.