Olefin Polymer Multistage Catalyst for Moldability and Rigidity
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Solution Overview
Problem
Conventional methods fail to produce polypropylene and propylene-based polymers that simultaneously exhibit high melt flow rate, broad molecular weight distribution, low xylene-soluble components, and high rigidity, which are essential for excellent moldability and mechanical strength.
Innovation Solution
A novel olefin polymer production method involving a contact reaction product of an olefin polymerization catalyst containing titanium, magnesium, and a halogen atom, combined with specific organoaluminum and electron donating compounds, to achieve a propylene polymer with targeted properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multistage polymerization is performed using a plurality of polymerization reactors to obtain broad molecular weight distribution, then moldability is improved, but xylene-soluble components increase and rigidity deteriorates
Solution Approach 1:
The patent segments the polymerization process into multiple stages with different catalyst systems and electron donating compounds, each stage producing polymer fractions with specific molecular weights and stereoregularity. This allows control over both molecular weight distribution (for moldability) and xylene-soluble content (for rigidity) by optimizing each segment's contribution to the final blend.
Solution Approach 2:
The patent changes multiple parameters including catalyst type, electron donating compound selection, polymerization temperature, and stage duration to simultaneously achieve broad molecular weight distribution and low xylene-soluble content. By adjusting these parameters across different polymerization stages, the invention optimizes both moldability and rigidity.
2Quantity of substance
If two or more catalysts are mixed or combined to obtain broad molecular weight distribution, then apparent molecular weight distribution broadens, but melting point decreases and heat resistance deteriorates
Solution Approach 1:
Instead of mixing catalysts simultaneously, the patent segments their application across different polymerization stages. Each catalyst system operates independently at optimized conditions, producing polymer fractions with controlled molecular weights and high stereoregularity, thereby maintaining melting point and heat resistance while achieving broad overall distribution.
Solution Approach 2:
The patent performs preliminary polymerization with specific catalyst-electron donating compound combinations before introducing other catalysts. This preliminary action establishes a foundation of high-stereoregularity polymer that maintains thermal properties while subsequent stages broaden the molecular weight distribution.
3Quantity of substance
If specific silicon compound is used during polymerization to obtain broad molecular weight distribution, then molecular weight distribution broadens, but xylene-soluble components increase and rigidity deteriorates
Solution Approach 1:
The patent uses specific electron donating compounds as intermediaries between the catalyst and monomer. These compounds modulate the catalyst activity to produce desired molecular weight distribution while maintaining high stereoregularity and low xylene-soluble content, thereby preserving rigidity despite broad distribution.
Solution Approach 2:
The patent changes the type and concentration of electron donating compounds used with specific silicon compounds to optimize the balance between molecular weight distribution breadth and xylene-soluble content. By adjusting these parameters, the invention achieves broad distribution without sacrificing rigidity.
4Ease of operation
If external electron donating compounds are used to achieve high stereoregularity and broad molecular weight distribution, then moldability improves, but production complexity increases
Solution Approach 1:
The patent merges multiple functions into a unified multistage polymerization process. Different catalyst systems, electron donating compounds, and polymerization conditions are combined in sequence within the same reactor system, achieving broad molecular weight distribution and high stereoregularity while consolidating equipment requirements and simplifying overall production.
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 method results in olefin polymers with improved lightness, moldability, and high rigidity, producing molded products with excellent flexural elasticity and controlled xylene-soluble content.
Implementation Method 1
an olefin polymerization catalyst which is a contact reaction product of an olefin polymerization solid catalyst component containing a titanium atom, a magnesium atom, a halogen atom and an internal electron donating compound
Implementation Method 2
a first external electron donating compound; and a polypropylene part formed of propylene polymerization product formed in the presence of the olefin polymerization catalyst and a second external electron donating compound
Data Source
AI summary
Provided is a novel olefin polymer which is excellent in lightness and moldability, has high rigidity and yields molded products excellent in flexural elasticity. The olefin polymer includes a propylene initial polymerization product formed in the presence of an olefin polymerization catalyst which is a contact reaction product of an olefin polymerization solid catalyst component containing a titanium atom, a magnesium atom, a halogen atom and an internal electron donating compound, at least one organoaluminum compound selected from the compounds of the general formula (I), and a first external electron donating compound; and a polypropylene part formed of a propylene polymerization product formed in the presence of the olefin polymerization catalyst and a second external electron donating compound higher in adsorption to the surface of the olefin polymerization solid catalyst component than the first external electron donating compound.