Metallocene Catalyst Ligand Substitution for Polymer Melting Point
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Solution Overview
Problem
There is a need for new and improved catalyst systems for olefin polymerization to achieve specific polymer properties such as high melting point, high molecular weights, increased conversion, or altered comonomer distribution without compromising polymer quality.
Innovation Solution
A novel group 4 transition metal metallocene catalyst compound with symmetrically substituted indenyl ligands, featuring cyclopropyl groups at the 2 and 8 positions and substituted phenyl groups at the 4 and 10 positions, is used, along with a bridging group and an activator to enhance catalyst productivity and polymer properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional metallocene catalysts are used for olefin polymerization, then catalyst activity is maintained, but polymer melting point and molecular weight are limited
Solution Approach 1:
The patent applies local quality by introducing specific substituents (cyclopropyl groups at 2,8-positions and phenyl groups at 4,10-positions) at specific locations on the indenyl ligands. These localized structural modifications create a catalyst with enhanced ability to produce high melting point polymers while maintaining catalyst activity, resolving the contradiction between improving polymer properties and maintaining catalyst versatility.
2Ease of manufacture
If catalyst structure is simplified for ease of manufacture, then manufacturing cost decreases, but polymer properties such as molecular weight and melting point are compromised
Solution Approach 1:
The patent employs segmentation by dividing the catalyst structure into distinct functional components: the indenyl ligand framework, cyclopropyl substituents at 2,8-positions, and phenyl substituents at 4,10-positions. This modular approach allows each component to be optimized independently for its specific function while maintaining overall catalyst performance, enabling both ease of manufacture through standardized synthesis steps and precise control over polymer properties.
3Productivity
If catalyst productivity is increased to improve output, then production efficiency increases, but polymer molecular weight and quality may deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure parameters of the metallocene catalyst, specifically incorporating cyclopropyl groups at the 2,8-positions and phenyl groups at the 4,10-positions of the indenyl ligands. These structural parameter changes optimize the catalyst's electronic and steric properties, enabling it to maintain high productivity while simultaneously producing polymers with enhanced molecular weight and quality, thus resolving the contradiction between productivity and polymer properties.
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 system produces propylene polymers with high melting points and molecular weights while maintaining good activity and productivity, achieving improved polymer properties compared to conventional methods.
Implementation Method 1
A novel group 4 transition metal metallocene catalyst compound with symmetrically substituted indenyl ligands, featuring cyclopropyl groups at the 2 and 8 positions and substituted phenyl groups at the 4 and 10 positions, is used, along with a bridging group and an activator to enhance catalyst productivity and polymer properties.
Data Source
AI summary
This invention relates to a novel group 2, 3 or 4 transition metal metallocene catalyst compound having two indenyl ligands with identical substitution including, for example, cyclopropyl groups and substituted phenyl groups at the 2 and 4 positions of the catalyst, respectively, where the substituents are at the 3′ and 5′ positions of the phenyl groups.