Olefin Polymerization Catalyst with Cyclic Ester Donor
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Solution Overview
Problem
Current catalysts for olefin polymerization fail to adequately broaden molecular weight distribution and improve melt tension, which is essential for high-speed stretching and molding processes, and lack a simple and cost-effective process for producing olefin polymers with these properties.
Innovation Solution
A catalyst system comprising a solid titanium catalyst component with a specific cyclic ester compound and an organometallic compound at a particular ratio, which includes a cyclic ester compound represented by a specific formula and an organometallic compound containing metal elements from Groups I, II, and XIII, is used for olefin polymerization, allowing for the production of polymers with broad molecular weight distribution and high melt tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a catalyst comprising a solid titanium catalyst component with electron donor and organometallic compound is used, then polymerization activity and stereospecificity are improved, but molecular weight distribution becomes narrow which results in low melt flowability and low melt tension
Solution Approach 1:
The patent changes the chemical parameters of the electron donor by introducing a cyclic structure with specific carbon atom counts (5-10 carbons) and specific substituent patterns. This parameter change in the catalyst composition broadens the molecular weight distribution while maintaining stereospecificity, thereby improving melt tension without sacrificing polymerization activity or stereoregularity.
Solution Approach 2:
The patent creates a composite catalyst system combining the solid titanium catalyst component with specific cyclic ester electron donors and organometallic compounds in controlled ratios. This composite approach allows the synergistic effect of multiple components to achieve both narrow molecular weight distribution for stereospecificity and broad distribution for improved melt properties, resolving the contradiction between these two requirements.
2Manufacturing precision
If polymers with narrow molecular weight distributions are produced, then stereoregularity is improved, but productivity in high speed stretching and molding is reduced due to low melt tension
Solution Approach 1:
The patent modifies the molecular weight distribution parameters by selecting specific cyclic ester compounds with defined carbon atom counts and structural features. This controlled parameter change enables the catalyst to produce polymers with optimized molecular weight distributions that simultaneously achieve high stereoregularity and sufficient melt tension for high-speed processing, thereby improving both manufacturing precision and productivity.
Solution Approach 2:
The patent applies local quality by using specific cyclic ester electron donors with particular structural characteristics (cyclic backbone with 5-10 carbons, specific substituent positions) to create localized catalytic sites that promote both stereospecific polymerization and broader molecular weight distribution. This localized structural approach allows different regions of the polymer chain to exhibit optimized properties for both stereoregularity and processability.
3Ease of manufacture
If conventional catalysts are used, then polymerization process is simple, but molecular weight distribution cannot be adequately broadened and melt tension remains insufficient
Solution Approach 1:
The patent optimizes the catalyst system by adjusting the parameters of the electron donor (cyclic ester structure with specific carbon counts) and the ratio of catalyst components. These parameter changes enable the catalyst to produce polymers with broader molecular weight distributions and higher melt tension while maintaining a relatively simple one-step polymerization process, thus improving melt tension without significantly complicating manufacturing.
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 effectively produces olefin polymers with high stereoregularity, broad molecular weight distribution, and improved molding properties such as high-speed stretchability and moldability, addressing the limitations of existing catalysts by enhancing melt tension and rigidity.
Implementation Method 1
a catalyst for olefin polymerization comprising a solid titanium catalyst component (I) and an organometallic compound catalyst component (II)
Implementation Method 2
a solid titanium catalyst component (I) comprising a titanium compound and a magnesium compound, and a cyclic ester compound (a)
Data Source
AI summary
A catalyst for olefin polymerization of the present invention includes a solid titanium catalyst component (I) including titanium, magnesium, halogen, and a cyclic ester compound (a) represented by the following formula (1):wherein n is an integer of 5 to 10; R2 and R3 are each independently COOR1 or R, and at least one of R2 and R3 is COOR1; a single bond (excluding Ca—Ca bonds, and a Ca—Cb bond in the case where R3 is R) in the cyclic backbone may be replaced with a double bond; a plurality of R1's are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms; and a plurality of R's are each independently a hydrogen atom or a substituent, but at least one of R's is a hydrogen atom, and an organometal compound catalyst component (II). When this catalyst for olefin polymerization is used, an olefin polymer having a broad molecular weight distribution can be produced.