Biphenyl Phenol Catalyst for Predictable Polyolefin Control
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Solution Overview
Problem
Bimetallic catalyst systems used in polyolefin production face complexity in controlling polymer properties due to differing hydrogen responses of their components, making it difficult to predictably and controllably alter molecular weight and distribution.
Innovation Solution
A catalyst system comprising a first catalyst compound with a biphenyl phenol compound having essentially no hydrogen response, combined with another catalyst compound, allowing for the production of polymers with predictable and controllable properties by limiting the number of catalysts with hydrogen responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bimetallic catalyst systems are used to produce bimodal polyolefin resins, then the strength properties and processing characteristics are improved, but the control of polymer properties becomes complicated and less predictable due to differing hydrogen responses of the catalyst components
Solution Approach 1:
The patent changes the hydrogen response parameter of one catalyst component by selecting a metallocene catalyst with specific ligand structures (e.g., ansa-metallocenes with bulky substituents) that inherently exhibit reduced hydrogen sensitivity. This parameter modification allows the catalyst system to maintain bimodal production capability while reducing control complexity.
Solution Approach 2:
The patent applies local quality by assigning different functional characteristics to different catalyst components: one catalyst component is optimized for producing high molecular weight fraction with minimal hydrogen response, while the other component produces the low molecular weight fraction. This localized functional differentiation simplifies overall control by making each component's behavior more predictable.
2Productivity
If bimetallic catalyst systems are used to produce bimodal polyolefin resins, then the processing characteristics are improved, but the predictability of polymer properties deteriorates due to additional independent variables affecting polymerization dynamics
Solution Approach 1:
The patent extracts the hydrogen response variable from one of the catalyst components by selecting a metallocene catalyst with structurally determined low hydrogen sensitivity. This extraction reduces the number of active independent variables in the system, thereby improving predictability while maintaining the ability to produce bimodal distributions through controlled catalyst ratios and activation conditions.
3Quantity of substance
If catalyst components with different hydrogen responses are used in bimetallic catalysts, then bimodal molecular weight distributions can be produced, but the control of molecular weight and distribution becomes more complicated
Solution Approach 1:
Instead of using two catalyst components both with high hydrogen response and trying to differential control them, the patent inverts the approach by selecting one component with inherently low hydrogen response. This inversion simplifies the control mechanism by making one catalyst's output relatively insensitive to hydrogen concentration changes, thereby easing operational control while maintaining bimodal distribution capability.
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
This approach simplifies the control of polymer properties by reducing independent variables affecting polymerization dynamics, enabling the production of polymers with bimodal molecular weight distributions in a single reactor with improved predictability and stability.
Implementation Method 1
catalyst systems useful for the production of polymers. The catalyst system may comprise one or more catalyst compounds having a nil or negligible hydrogen response
Data Source
AI summary
A polymerization catalyst system and polymerization processes using the catalyst systems are disclosed. The polymerization catalyst systems may include a) a first catalyst compound, and b) a second catalyst compound, wherein the first catalyst compound comprises a biphenyl phenol compound having essentially no hydrogen response.