Trioxasilocane Catalyst System for Olefin Polymerization
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Solution Overview
Problem
Existing Ziegler-Natta catalyst systems face a trade-off between promoting isotacticity and maintaining catalytic activity when using organosilane compounds for olefin polymerization, resulting in reduced performance in other polymer characteristics such as melt-flow ability and molecular weight distribution.
Innovation Solution
A catalyst system comprising a transition metal compound, an organic metal compound, and a cyclic organosilane compound (trioxasilocane) as an external electron donor, optimized with specific molar ratios and structural configurations to enhance polymerization activity, melt-flow ability, and isotacticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If organosilane compounds are used as external electron donors to promote isotacticity, then isotacticity is improved, but catalytic activity and other polymer characteristics (melt-flow ability, molecular weight distribution) deteriorate
Solution Approach 1:
The patent changes the chemical structure parameters of the organosilane compound by introducing a cyclic trioxasilocane structure with specific oxygen-containing rings. This structural modification allows the electron donor to achieve optimal balance between promoting isotacticity and maintaining catalytic activity, resolving the trade-off between these two parameters.
Solution Approach 2:
The patent creates a composite catalyst system by combining the cyclic trioxasilocane compound with transition metal compounds and organic metal compounds in specific molar ratios. This composite approach allows synergistic effects where the trioxasilocane enhances isotacticity while the overall system maintains high catalytic activity through the cooperative action of multiple components.
2Manufacturing precision
If organosilane compounds are used as external electron donors to improve polymer properties, then isotacticity is improved, but melt-flow ability and molecular weight distribution deteriorate
Solution Approach 1:
The patent modifies the molecular structure parameters of the electron donor by using cyclic trioxasilocane compounds with specific ring sizes and oxygen content. This structural parameter change enables better control over polymerization kinetics, resulting in improved molecular weight distribution while maintaining high isotacticity.
Solution Approach 2:
The patent employs a feedback mechanism through optimized molar ratios of the catalyst components. By adjusting the ratio of trioxasilocane to transition metal and organic metal compounds, the system self-regulates to achieve balanced polymerization, improving both isotacticity and molecular weight distribution simultaneously.
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 improves polymerization activity, melt-flow ability, isotacticity, and molecular weight distribution, producing polyolefins with enhanced properties while maintaining high catalytic activity.
Implementation Method 1
a cyclic organosilane compound, trioxasilocane as an external electron donor
Implementation Method 2
a catalyst system for olefin polymerization comprising a transition metal compound as a main catalyst component
Data Source
AI summary
The present invention relates to a catalyst system for olefin polymerization and a method for olefin polymerization using the same. More particularly, the present invention relates to a Ziegler-Natta catalyst system for olefin polymerization comprising a transition metal compound as a main catalyst component, an organic metal compound as a cocatalyst component, and a cyclic organosilane compound, trioxasilocane as an external electron donor, and a method for olefin polymerization using the same. According to the present invention, a polyolefin having improved various properties such as polymerization activity, melt-flow ability, isotacticity, molecular weight distribution and apparent density can be produced.