Low-pressure high-density polyethylene catalyst, preparation method and application thereof

Abstract

The present invention relates to one kind of catalyst for preparing low pressure high density polyethylene and its preparation process and application. The preparation process includes the following steps: 1. grinding anhydrous MgCl2 and Al2O3 in nitrogen environment; and 2. dispersing the ground product in liquid alkane solution, adding anhydrous alcohol and alkyl titanate, cooling and adding alkyl aluminum; adding inorganic ammonium salt, adding titanium tetrachloride; soaking the catalyst substrate; adding alkyl aluminum to activate and drying to obtain the catalyst. The catalyst may be dispersed in liquid alkane to obtain catalyst suspension. The catalyst is applied in polymerization or copolymerization of ethylene monomer, and has high catalytic activity, and capacity of resulting in smooth polymerization reaction and raising polymer quality.

Description

technical field [0001] The invention relates to a low-pressure high-density polyethylene catalyst and its preparation method and application, in particular to a preparation method of a combined support type low-pressure high-density polyethylene (HDPE) catalyst, which is suitable for ethylene in a continuous tank slurry reaction Monomer polymerization or copolymerization of ethylene and alpha-olefins. Background technique [0002] At present, in the production of low-pressure high-density polyethylene (HDPE) in the domestic continuous tank slurry reaction, Ziegler-Natta (Ziegler-Natta) titanium (Ti) series catalysts with a single carrier (magnesium chloride as the carrier) are used. . Due to the irregular particle shape of the single magnesium chloride carrier, the irregularity of the polyethylene resin particles generated in the polymerization reaction, especially the fine powder particles, can easily lead to the generation of static electricity during the production proce...

AI Technical Summary

Problems solved by technology

Due to the irregular particle shape of the single magnesium chloride carrier, the irregularity of the polyethylene resin particles generated in the polymerization reaction, especially the fine powder particles, can easily lead to the generation of static electricity during the production process. The hardening of resin, the blockage of resin delivery pipes, etc. are not conducive to the normal continuous production, and because the majority of resin particles are fine powder, the bulk density of polyethylene powder resin decreases, which affects the production output and resin product quality.

[0003] At present, in the domestic use of catalysts, it often occurs that the activity of the catalyst is not stable enough, and the bulk density of the resin also fluctuates accordingly. As a result, in the polymerization production, the process parameters of the production process must be adjusted according to the polymerization reaction of the catalyst to provide long-term stability. Production has brought great inconvenience