Dual Transition Metal Catalyst for Slurry Polyolefin Fouling
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Solution Overview
Problem
Conventional catalysts face challenges in producing very low density polyethylene with high productivity and stability in the slurry process due to inferior copolymerizability, solvent solubility issues, and fouling problems, making it difficult to achieve desired polymer properties.
Innovation Solution
A catalyst composition comprising a specific molar ratio of first and second transition metal compounds, represented by Chemical Formulas 1 and 2, is used in a slurry polymerization process, enhancing copolymerizability and process stability, preventing fouling, and producing polyolefins with excellent mechanical and physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional catalysts are used in slurry polymerization, then productivity can be maintained, but copolymerizability is inferior and process stability deteriorates
Solution Approach 1:
The patent employs a composite catalyst system combining metallocene catalyst (Formula 1) and post-metallocene catalyst (Formula 2) with specific molar ratios. This composite catalyst integrates the high copolymerizability of metallocene catalysts with the process stability of post-metallocene catalysts, resolving the contradiction between adaptability and reliability in slurry polymerization
2Productivity
If very low density polyethylene is produced in slurry process, then productivity decreases due to solvent solubility and polymer swelling, but the process becomes unstable and fouling occurs
Solution Approach 1:
The patent optimizes the density of very low density polyethylene to 0.880-0.920 g/cm³ through controlled copolymerization parameters and catalyst composition. This parameter optimization prevents excessive polymer swelling and solvent solubility issues, maintaining both high productivity and process stability without fouling
3Adaptability or versatility
If catalyst composition is optimized for high copolymerizability, then very low density polyethylene can be produced, but mechanical stability of polymer decreases
Solution Approach 1:
The patent applies local quality by using a dual-catalyst system where metallocene catalyst (Formula 1) provides high copolymerizability for very low density regions, while post-metallocene catalyst (Formula 2) contributes to mechanical stability. The specific molar ratio optimization ensures local functional differentiation within the catalyst system, achieving both high copolymerizability and polymer mechanical stability
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 catalyst composition improves process stability and polymerization activity, enabling the production of polyolefins with high mechanical stability and desired physical properties, such as very low density polyethylene, while preventing fouling and productivity issues.
Implementation Method 1
a catalyst composition comprising a first transition metal compound (A) represented by Chemical Formula 1 and a second transition metal compound (B) represented by Chemical Formula 2
Implementation Method 2
The metallocene catalyst consists of a combination of a main catalyst in which a transition metal compound is a main component and an organometallic compound
Data Source
AI summary
A catalyst composition, a method of preparing a polyolefin including the same, and a polyolefin prepared from the same are disclosed herein. In some embodiments, a catalyst composition comprises a first transition metal compound represented by Chemical Formula 1, and a second transition metal compound represented by Chemical Formula 2, wherein a molar ratio of the first transition compound to the second transition metal compound ranges from 1:0.3 to 1:3.5. The catalyst composition is capable of preparing a polyolefin having excellent mechanical stability, while exhibiting excellent process stability and high polymerization activity during the preparation of a polyolefin in a slurry process.