Olefin Metathesis Catalyst Composition for Thin-Wall Cure Control
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Solution Overview
Problem
Existing olefin metathesis polymerization catalysts are sensitive to humidity and moisture, leading to slow initiation, low monomer conversion, and difficulty in molding thin-walled articles, with flash parts often remaining uncured and difficult to remove.
Innovation Solution
A catalyst system comprising a metalate-based pre-catalyst and an alkoxyalkylaluminum halide complex co-catalyst with specific pKa and functionalized alkoxy ligands, which provides faster initiation and higher monomer conversion, allowing the production of thin-walled molded articles with improved cure quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional catalyst systems (such as those based on aluminum alkyls or metal oxides) are used for polymerization, then the catalyst can be activated, but the polymerization process suffers from poor control over molecular weight distribution, unwanted side reactions, and inability to produce specific polymer architectures
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by using transition metal complexes (such as tungsten, molybdenum, or nickel complexes) with specific ligands and oxidation states. This allows precise control over polymerization parameters including molecular weight, polydispersity index, and polymer architecture, transforming the uncontrolled conventional process into a highly controllable modern polymerization system.
Solution Approach 2:
The invention employs composite catalyst systems combining transition metal complexes with specific ligands and co-catalysts. This composite approach enables simultaneous control of multiple polymerization parameters and suppression of side reactions, achieving both high manufacturing precision and reliable polymerization control that conventional single-component catalysts cannot accomplish.
2Manufacturing precision
If conventional catalyst systems are used, then polymerization can proceed, but the process lacks selectivity and produces unwanted by-products and polymers with broad molecular weight distributions
Solution Approach 1:
The patent applies local quality by designing catalyst complexes with specific ligand environments around the metal center. This creates a localized active site with precise geometric and electronic properties that favor desired polymerization reactions while suppressing unwanted side reactions, thereby improving both manufacturing precision and reducing harmful by-products.
Solution Approach 2:
By changing the chemical parameters of the catalyst (metal identity, oxidation state, ligand types and arrangements), the invention achieves high selectivity for desired polymerization pathways. This parameter optimization enables production of polymers with narrow molecular weight distributions and specific architectures while minimizing harmful side reactions.
3Adaptability or versatility
If existing catalyst systems are used for olefin polymerization, then polymerization occurs, but the process cannot achieve controlled living polymerization or produce specific polymer architectures with precision
Solution Approach 1:
The patent employs dynamic catalyst systems that can adjust their activity and selectivity during the polymerization process. This dynamic behavior enables control over polymer architecture and molecular weight distribution in real-time, allowing production of specific polymer types (block copolymers, graft copolymers, star-shaped polymers) with precise control over their characteristics.
Solution Approach 2:
The invention uses transition metal complexes with tunable parameters (metal identity, ligand types, stoichiometry) to achieve controlled living polymerization. This parameter control enables precise manipulation of molecular weight, polydispersity index, and polymer architecture, providing both adaptability for different polymer types and precision for molecular characteristics.
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 achieves monomer conversion rates above 90%, ensuring complete cure of flash parts and enabling the production of thin-walled articles with thicknesses between 0.2 and 4 mm, facilitating easy removal of flash parts.
Implementation Method 1
The invention relates to olefin metathesis polymerization catalysts and compositions containing the catalysts
Data Source
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AI summary
Disclosed is an olefin metathesis polymerization catalyst system. The catalyst system comprises a metalate as pre-catalyst and an aluminum complex as co-catalyst, wherein the aluminum complex is an alkoxyalkylaluminum halide complex [(OR1)(R2)AlX1]n wherein OR1 is an alkoxy ligand derivable from an alcohol with a pKa in the range of from 18-30, wherein the alkoxy is optionally functionalized and wherein further n is an integer in the range of from 1-3, R2 is an alkyl, and X1 is an halide. Also disclosed is a method of manufacturing a molded article of a curable composition comprising the catalyst system. The method comprises providing the curable composition by combining the cyclic olefin and the olefin metathesis polymerization catalyst system in a mold; subjecting the composition to conditions effective to promote an olefin metathesis reaction of the cyclic olefin in the closed mold; and taking the reacted composition out of the mold to obtain the molded article. With the method a thin-walled article of a cyclic olefin polymer may be obtained having a glass transition temperature Tg above 60°C.