Catalyst for polymerizing olefin and its prepn process

Abstract

The present invention relates to catalyst for polymerization and copolymerization of olefin and its preparation process. The catalyst is obtained through dissolving magnesium halide in homogeneous solution of organic epoxy compound, organophosphorus compound and electron donor compound, and the reaction with the mixture solution of titanium halide or its derivative and liquid co-precipitant. Using the liquid co-precipitant intersoluble with titanium compound can omit the step of dissolving separating assistant, is favorable to the depositing separation of catalyst mother liquid system, raises the yield of the catalyst, avoids the residue of co-precipitant in catalyst product and raises the quality of polymer. The catalyst for polymerization and copolymerization of olefin has high activity and results in good polymer state.

Description

Field of invention: [0001] The present invention relates to a catalyst for olefin polymerization or copolymerization and its preparation method. Background of the invention: [0002] Since the 1970s, Japan's Mitsui Petrochemical Industry Co., Ltd. and other companies have successfully developed a variety of Ti-Mg high-efficiency carrier catalysts with magnesium chloride as the carrier, which has enabled the rapid development of the world's slurry production of polyolefin industry. A more representative technology is the method of ethylene polymerization and copolymerization disclosed by Mitsui Oil & Chemical in Japanese Patent JP49-51378. The specific preparation method of the catalyst is: the reaction of magnesium dichloride and ethanol after grinding and pulverizing in a lamp oil medium to form MgCl 2 ·6C 2 h 5 OH alcoholate slurry, and then react with diethylaluminum chloride to remove most of the ethanol, and finally use titanium tetrachloride for titanium loading rea...

AI Technical Summary

Problems solved by technology

[0005] Although the catalyst systems of the above two patents have good performance for olefin polymerization, the former is more inclined to propylene polymerization, and the latter is more inclined to ethylene polymerization, but in order to obtain catalyst solids in the preparation process of the above two catalyst systems, both The method of adding a precipitation aid is adopted. The more effective precipitation aid is one of organic acid anhydrides, organic acids, ethers, and ketones. Especially when phthalic anhydride is used as a precipitation aid, the effect is better. The method is Phthalic anhydride must be completely dissolved in the mixed solvent system first, and then cooled and mixed with the titanium compound. During the mixing process, the catalyst solid grows from scratch in the mother liquor system and gradually aggregates and grows. In order to obtain a good catalyst particle shape, therefore The mixing speed and reaction temperature of the system need to be strictly controlled, and generally a longer heating time is required, so the use of this type of precipitation aid prolongs the preparation period of the catalyst accordingly

In addition, the above-mentioned precipitation aid system is relatively toxic, requires high operating conditions, and is expensive