Silica-Supported Metallocene Catalyst Preparation for Uniform Polyolefin
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Solution Overview
Problem
Existing metallocene catalysts face challenges in achieving both high olefin polymerization activity and uniform polyolefin powder morphology, particularly in slurry and gas-phase processes, leading to issues like reactor fouling and inefficient process productivity due to non-uniform particle shapes.
Innovation Solution
A method involving the sequential support of aluminum alkyl halide, cocatalyst compound, and metallocene compound on a silica-based carrier, with aluminum alkyl halide predominantly on the surface and cocatalyst compound inside the pores, to enhance catalytic activity and achieve uniform polyolefin powder morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a metallocene catalyst is used in slurry or gas-phase polymerization, then olefin polymerization activity is improved, but the catalyst may leach and cause reactor fouling
Solution Approach 1:
The patent employs a silica-based carrier with controlled pore structure to support the metallocene catalyst. The porous structure provides high surface area for catalyst support while preventing leaching, resolving the contradiction between maintaining high polymerization activity and preventing reactor fouling.
Solution Approach 2:
The patent creates a composite catalyst system consisting of metallocene compound, aluminum alkyl halide, and silica-based carrier. This composite structure combines the high activity of metallocene with the stability and support properties of silica, preventing catalyst leaching while maintaining polymerization efficiency.
2Productivity
If a supported metallocene catalyst is used, then polymerization activity is improved, but non-uniform particle shape of polyolefin increases generation of fines
Solution Approach 1:
The patent applies local quality by creating distinct zones within the catalyst structure: aluminum alkyl halide is supported on the external surface while the metallocene compound is supported inside the pores. This spatial differentiation controls polymerization location and heat distribution, leading to uniform particle morphology and reduced fines generation.
Solution Approach 2:
The patent optimizes specific parameters including the SiO2 surface area (50-500 m2/g), pore volume (0.1-1.0 mL/g), and the ratio of aluminum alkyl halide to metallocene compound. These parameter adjustments control the polymerization process to produce uniform polyolefin particles with desired morphology.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The supported metallocene catalyst exhibits excellent olefin polymerization activity while producing polyolefin with a uniform powder morphology, reducing fines and reactor fouling, thereby improving process stability and efficiency.
Implementation Method 1
aluminum alkyl halide is supported at higher rate on the surface of the silica-based carrier than insides the pores of the silica-based carrier, and the cocatalyst compound is supported at higher rate insides the pores of eth silica-based carrier than on the surface of the silica-based carrier
Implementation Method 2
supporting a metallocene compound in the carrier in which the aluminum alkyl halide and the cocatalyst compound are supported... polymerizing olefin monomers in the presence of the supported metallocene catalyst to obtain polyolefin
Data Source
Figure 1~A2
AI summary
This invention relates to a method for preparing a supported metallocene catalyst, a supported metallocene catalyst and a method for preparing polyolefin using the same. According to this invention, a method for preparing a supported metallocene catalyst that not only has excellent olefin polymerization activity, but also enables preparation of polyolefin having a uniform powder morphology, a supported metallocene catalyst prepared by the method, and a method for preparing polyolefin using the supported metallocene catalyst are provided.