Dual NCA Activator Catalyst for Bimodal Polymer Distribution
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Solution Overview
Problem
Current polymerization processes using metallocene catalysts with single non-coordinating anion activators lack the ability to systematically control molecular weight and compositional distribution, limiting post-reactor processing and industrial applications.
Innovation Solution
A catalyst system comprising a transition metal compound paired with at least two boron-containing non-coordinating anion (NCA) activators, where one NCA is a Bronsted acid and the other is a reducible Lewis acid, allowing for the formation of bimodal molecular weight distribution and controlled comonomer incorporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single non-coordinating anion activator is used with metallocene catalyst, then the catalyst produces precise polymerization with narrow molecular weight distribution, but the narrow distribution hinders post-reactor processing
Solution Approach 1:
The invention divides the activator function into two separate components: a first non-coordinating anion activator that produces narrow molecular weight distribution polymer, and a second different non-coordinating anion activator that produces broader distribution polymer. This segmentation allows each activator to be optimized for specific polymerization characteristics, enabling control over the final polymer distribution while maintaining processing capability.
Solution Approach 2:
The invention combines two different non-coordinating anion activators in a single catalyst system with the metallocene catalyst compound. The first and second activators work together to produce a polymer with controlled molecular weight distribution that balances both precision and processability, resolving the contradiction between narrow distribution precision and post-reactor processing capability.
2Adaptability or versatility
If multiple catalyst/activator pairings are used, then different polymer products with varying molecular weight and comonomer content can be produced, but the system complexity increases
Solution Approach 1:
The invention creates a universal catalyst system framework where a single metallocene catalyst compound can be paired with multiple different non-coordinating anion activators to produce various polymer products. This multi-functional system allows control over molecular weight distribution and comonomer content while maintaining a consistent catalyst structure, thereby achieving versatility without proportionally increasing system complexity.
3Productivity
If alumoxane is combined with ionizing activator, then polymerization can proceed, but the ability to systematically control molecular weight and compositional distribution is limited
Solution Approach 1:
The invention changes the chemical parameters of the activator system by using two different non-coordinating anion activators with distinct properties. The first activator is optimized for producing polymer with narrow molecular weight distribution, while the second activator is optimized for broader distribution. This parameter change enables systematic control over the final polymer characteristics while maintaining high polymerization activity.
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 use of dual NCA activators in the catalyst system enables precise control of polymer molecular weight and compositional distribution, enhancing the productivity and activity of the catalyst, and producing polymers with improved properties.
Implementation Method 1
contacting one or more olefins with a catalyst system comprising a transition metal catalyst compound and at least two boron containing non-coordinating anion (NCA) activators
Implementation Method 2
formation of bimodal molecular weight distribution and controlled comonomer incorporation
Data Source
AI summary
This invention relates to a method to polymerize olefins comprising contacting olefins with a catalyst system comprising a transition metal catalyst compound and: 1) at least two NCA activators represented by the formula: Zd+ (Ad-), where Z is a Bronsted acid or a reducible Lewis acid, Ad- is a boron containing NCA, d is 1, 2, or 3, and where Z is a Bronsted acid and Z is a reducible Lewis acid in the first and second NCA activators, respectively; or 2) at least two NCA activators, one as described in Formula I and one not as described in Formula I; or 3) two NCA activators as described in Formula I except that the N in the second NCA in the ArNHal is at a different position in the nitrogen containing aromatic ring than the N in the first NCA.