Metallocene Complex for High-Melting Propylene Polymerization
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Solution Overview
Problem
Conventional metallocene catalysts face challenges in achieving high ethylene uptake efficiency and producing propylene-based polymers with high molecular weight and impact resistance, leading to issues with gel formation and odor problems during processing.
Innovation Solution
A metallocene complex with specific substituents, including a cyclic structure on carbon, silicon, or germanium atoms crosslinking indenyl ring moieties, and a furyl or thienyl group on the 2-position of the indenyl ring, is used to enhance ethylene uptake and polymerization activity, resulting in high-melting-point homopolypropylene and ethylene-propylene copolymers with improved rigidity and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional Ziegler-Natta catalyst is used for copolymerization to improve impact resistance, then rubber component content can be increased, but low-molecular-weight components are generated causing odor problems and processing issues
Solution Approach 1:
The patent changes the catalyst parameters by using metallocene-based catalysts with specific ligand structures (Cp2ZrCl2, Cp2HfCl2, Cp2TiCl2) to control polymerization. This parameter change enables selective polymerization that produces high-molecular-weight rubber components without generating low-molecular-weight contaminants, thereby eliminating odor problems while maintaining impact resistance
Solution Approach 2:
The patent creates composite polymer materials by copolymerizing propylene with ethylene or α-olefin using metallocene catalysts. The resulting impact copolymers combine crystalline polypropylene matrix with rubbery copolymer phases, achieving both high impact resistance and high molecular weight without harmful low-molecular-weight components
2Temperature
If metallocene-based catalyst is used to produce high-melting-point polypropylene, then rigidity is improved, but ethylene uptake efficiency decreases
Solution Approach 1:
The patent applies local quality by modifying specific positions on the metallocene ligand structure. Substituents are placed at the 2-position and 5-position of the cyclopentadienyl rings to create localized electronic and steric effects that simultaneously enhance propylene polymerization activity (for high melting point) and ethylene coordination efficiency (for high uptake efficiency)
Solution Approach 2:
The patent changes the catalyst parameters by introducing specific substituents (aryl groups, alkyl groups, or hydrogen atoms) at defined positions on the metallocene ligands. This parameter modification optimizes the balance between propylene polymerization rate and ethylene copolymerization efficiency, achieving both high melting point polypropylene and high ethylene uptake
3Strength
If rubber component content is increased to enhance flexibility and impact resistance, then impact resistance is improved, but gel formation and coefficient of linear expansion increase
Solution Approach 1:
The patent changes the molecular weight distribution parameters by using metallocene catalysts that produce narrow molecular weight distributions. This parameter control ensures that rubber components are incorporated at controlled molecular weights, preventing gel formation while maintaining high impact resistance and stable linear expansion 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 novel metallocene complex achieves balanced rigidity and impact resistance in propylene-based polymers, reducing gel formation and odor issues, while maintaining high ethylene uptake efficiency, thus improving the production of high-quality propylene-based polymers.
Implementation Method 1
a metallocene complex having a substituent introduced into a specific position, which can produce a high-melting-point polypropylene and in the copolymerization of propylene and ethylene, can provide a high ethylene uptake efficiency
Data Source
AI summary
The present invention provides a metallocene complex capable of producing a homopolypropylene having a high melting point in the homopolymerization of propylene, and a production method of an olefin polymer using the same. The metallocene complex of the present invention is represented by formula [I]: (In formula [I], definitions of the substituents have the same meanings as in the description).