Metallocene Catalyst for High Melting Polyolefins
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Solution Overview
Problem
Metallocene catalysts face challenges in producing polyolefins with high melting temperature and low melt flow rate while maintaining other desirable properties such as high activity and broad molecular weight range.
Innovation Solution
A new metallocene catalyst system with a specific formula (I) is introduced, comprising transition metals like zirconium, with specific groups and substituents that enhance activity and crystallinity, used in olefin polymerization processes to produce polyolefins with improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional metallocene catalysts are used to produce high melting temperature or low melt flow rate polypropylene, then the desired polymer properties are achieved, but the catalyst activity decreases
Solution Approach 1:
The patent applies local quality by introducing specific alkoxy substituents at particular positions on the metallocene ligand structure. The formula specifies that at least one of R3, R4, R5, R6, or R7 must be -OR15, creating localized functional groups that modify the catalyst's electronic and steric properties. This localized modification enables the catalyst to produce high melting temperature polypropylene while maintaining high activity, resolving the contradiction between polymer properties and catalyst productivity.
Solution Approach 2:
The patent employs parameter changes by systematically varying the metallocene catalyst structure through different substituents (R1-R17) and their configurations. The specific parameter changes include introducing alkoxy groups (-OR15) with varying alkyl chains, adjusting the bridge structure (L1), and modifying the ligand substitution patterns. These parameter modifications optimize both the catalyst activity and the resulting polypropylene melting temperature, eliminating the traditional trade-off.
2Manufacturing precision
If conventional metallocene catalysts are used to produce broad molecular weight range polypropylene, then the molecular weight distribution is improved, but the catalyst activity is reduced
Solution Approach 1:
The patent uses local quality by placing specific alkoxy substituents at defined positions on the metallocene ligand. This localized functional group placement creates specific electronic and steric environments at the catalytic center that favor broad molecular weight distribution while maintaining high activity. The localized modification approach allows independent optimization of polymer properties without sacrificing catalyst productivity.
3Stability of the object's composition
If conventional metallocene catalysts are used to increase crystallinity of polypropylene, then the degree of crystallinity is improved, but the catalyst activity decreases
Solution Approach 1:
The patent applies parameter changes by modifying the metallocene catalyst structure through systematic variation of substituents and their configurations. The introduction of alkoxy groups and adjustment of ligand parameters create a catalytic environment that promotes high crystallinity in the polypropylene product while maintaining high catalyst activity. This resolves the contradiction by finding optimal parameter combinations that simultaneously achieve both goals.
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 new catalyst system achieves high and stable activity, broad molecular weight range, and increased crystallinity, effectively addressing the limitations of existing metallocene catalysts in producing polyolefins with desired properties.
Implementation Method 1
Metallocene catalysts have been used to manufacture polyolefins for many years
Implementation Method 2
M1 is a transition metal selected from the group comprising zirconium, titanium, hafnium, and vanadium
Data Source
AI summary
The present invention relates to a catalyst of Formula (I) wherein R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, L1, M1, Q1 and Q2 have the meaning defined in the description and claims. The present invention also relates to a catalyst composition comprising at least one catalyst according to the invention. an optional activator: an optional support: and an optional co-catalyst. The present invention also relates to the use of a catalyst or catalyst composition according to the invention for the preparation of an olefin polymer. The present invention also relates to an olefin polymerization process. the process comprising: contacting a catalyst or a catalyst composition according to the invention, with an olefin monomer, optionally hydrogen, and optionally one or more olefin comonomers: polymerizing the monomer, and the optionally one or more olefin comonomers, in the presence of the at least one catalyst composition, and optional hydrogen, thereby obtaining an olefin polymer. The present invention also relates to olefin polymers and articles comprising said olefin polymer.