Nonsymmetric Bridged Amine Bis(phenolate) Catalysts for Polyolefin Processability
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Solution Overview
Problem
Current catalyst systems for polyolefin production face challenges in achieving high molecular weight polyolefins with narrow molecular weight distribution and high comonomer content, leading to processing difficulties and low catalyst activity.
Innovation Solution
Development of nonsymmetric bridged amine bis(phenolate) transition metal complexes as catalysts, which include zirconium or hafnium-containing compounds with benzyl ligands, used in combination with activators and optional supports for olefin polymerization, resulting in catalyst systems that produce polyolefins with high comonomer content, narrow polydispersity, and improved processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional Ziegler-Natta or metallocene catalysts are used to produce high molecular weight polyolefins, then molecular weight can be increased, but molecular weight distribution becomes broad and processing becomes difficult
Solution Approach 1:
The patent employs asymmetric ligand structures (nonsymmetric bridged amine bis(phenolate)) to create chiral catalyst environments that control polymer chain growth more uniformly, achieving narrow molecular weight distribution while maintaining high molecular weight, thus resolving the contradiction between molecular weight and processability
2Quantity of substance
If catalyst systems are designed to achieve high comonomer content incorporation, then copolymer properties are improved, but catalyst activity decreases
Solution Approach 1:
The patent modifies catalyst parameters including metal center selection (Group 4 transition metals), ligand structure (bridged amine bis(phenolate)), and steric/electronic properties to create catalysts that maintain high activity while incorporating high comonomer content, resolving the contradiction between comonomer content and catalyst activity
3Strength
If high molecular weight polyolefins are produced to achieve desirable mechanical properties, then mechanical strength is improved, but production cost increases and processing becomes costly
Solution Approach 1:
The patent employs inert atmosphere polymerization techniques to prevent unwanted side reactions and polymer degradation, enabling efficient production of high molecular weight polyolefins with excellent mechanical properties at reduced cost by minimizing waste and reprocessing needs
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 systems achieve high activity values, producing polyolefins with molecular weights exceeding 650,000 g/mol, narrow polydispersity indices, and high comonomer content, enhancing both polymer properties and processing characteristics.
Implementation Method 1
contacting one or more olefin monomers with a catalyst system including one or more catalysts, at least one activator, and an optional support to produce a polyolefin polymer
Data Source
AI summary
The present disclosure provides catalyst compounds including a nonsymmetric bridged amine bis(phenolate), catalyst systems including such, and uses thereof. Catalyst compounds, catalyst systems, and processes of the present disclosure can provide high comonomer content and high molecular weight polymers having narrow Mw/Mn values, contributing to good processability for the polymer itself and for the polymer used in a composition.