Olefin Polymerization Catalyst Composition for Controlled Molecular Weight Distribution
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Solution Overview
Problem
Conventional catalysts for olefin polymerization either limit α-olefin incorporation in high molecular weight polymers or result in uneven molecular weight distribution, restricting the range of polyolefin properties that can be achieved.
Innovation Solution
A catalyst composition comprising transition metal compounds with specific ligand structures, such as those with amido ligands linked to ortho-phenylene and fused with heterocyclic thiophene, combined with metallocene compounds, which allows for controlled molecular weight distribution and enhanced catalytic activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If heterogeneous catalysts are used for ethylene/α-olefin copolymerization, then high molecular weight polymer is produced, but α-olefin incorporation is limited and occurs primarily in low molecular weight polymer chains
Solution Approach 1:
The patent combines heterogeneous catalyst system with homogeneous catalyst system in a single reaction process. The heterogeneous catalyst (e.g., Cr, Mn, Fe compounds) provides high molecular weight polymer production, while the homogeneous catalyst (e.g., Group 4 metallocene compounds) provides uniform α-olefin distribution and high α-olefin incorporation. This merging allows simultaneous achievement of both advantages that cannot be obtained with either catalyst type alone.
2Stability of the object's composition
If homogeneous catalysts are used for ethylene/α-olefin copolymerization, then high α-olefin incorporation and uniform distribution are achieved, but high molecular weight polymer production is limited
Solution Approach 1:
The patent merges heterogeneous and homogeneous catalyst systems to overcome the limitations of each. The heterogeneous catalyst component enables production of high molecular weight polymer, while the homogeneous catalyst component ensures uniform α-olefin distribution and high incorporation levels, achieving both objectives simultaneously.
3Stability of the object's composition
If conventional metallocene catalysts are used, then narrow molecular weight distribution is achieved, but the range of polyolefin properties is limited
Solution Approach 1:
The patent changes the catalyst system parameters by combining conventional metallocene catalysts with other transition metal compounds (Cr, Mn, Fe compounds) and co-catalysts. This parameter change enables control over both narrow molecular weight distribution and a wide range of polyolefin properties, including molecular weight, α-olefin content, and copolymer composition, by adjusting the ratio and type of catalyst components.
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
Enables the production of polyolefins with a wide range of molecular weights and distributions, providing polymers with desired properties and improved copolymerization characteristics.
Implementation Method 1
A catalyst composition for olefin polymerization that comprises a transition metal compound represented by formula (1) and a transition metal compound represented by formula (2)... enables the production of polyolefins with a wide range of molecular weights and distributions
Data Source
AI summary
The present invention relates to a catalyst composition comprising a novel transition metal compound and a preparation method for polyolefin using the same. The catalyst composition of the present invention has high catalytic activity for polymerization of olefin-based monomers and enables it to control the fine-structure characteristics of the polyolefin, such as molecular weight distribution, in a wide range, thereby easily providing a polyolefin with desired properties.