Olefin Polymerisation Catalyst Particle Size Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for producing olefin polymerization catalysts result in low yields, unsatisfactory product morphology, and broad particle size distribution, leading to polymers with undesirable fines and medium narrow particle size distribution.
Innovation Solution
A process involving the controlled addition of a second organic liquid medium after mixing the alkaline earth metal complex with the transition metal compound, which influences particle size distribution and results in catalyst particles with a higher median and mode particle size, and a narrower particle size distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If precipitation is used to recover catalyst component from solution, then catalyst component is obtained, but product morphology is unsatisfactory and particle size distribution is broad
Solution Approach 1:
The invention changes the physical state parameter of the catalyst component from solid precipitate to liquid solution form. The catalyst component is kept in solution during the reaction and only solidified at the end of the polymerization process, transforming the recovery method from precipitation to controlled solidification, which resolves the contradiction between product morphology and catalyst yield
Solution Approach 2:
The invention performs preliminary action by pre-forming the catalyst component in solution before the polymerization reaction. The catalyst component is prepared and maintained in solution form throughout the polymerization process, and only solidified after polymerization is complete, avoiding the need for intermediate precipitation steps that compromise both morphology and yield
2Quantity of substance
If aliphatic hydrocarbon is used for precipitation, then catalyst component is recovered, but tar-like reaction product of low catalytic activity is formed
Solution Approach 1:
The invention uses an intermediary solvent system where the catalyst component remains dissolved in the aliphatic hydrocarbon solvent throughout the polymerization process. The solvent acts as a medium that keeps the catalyst component in solution form, preventing tar-like precipitation while maintaining catalytic activity. The catalyst component is only solidified after the reaction completes, ensuring high catalytic activity is preserved throughout
3Quantity of substance
If aromatic hydrocarbon is used for precipitation, then catalyst component is recovered, but very finely divided precipitate is formed which is difficult to deposit
Solution Approach 1:
The invention changes the physical state parameter of the catalyst component from solid precipitate to liquid solution. By maintaining the catalyst component in solution form during and after polymerization, and only solidifying it at the final stage, the invention eliminates the problem of fine precipitate formation and improves ease of deposition and handling
4Reliability
If precipitation is used to remove inactive metal complex, then amount of inactive metal complex is decreased, but washing time and process complexity increase
Solution Approach 1:
The invention maintains continuous useful action by keeping the catalyst component in solution form throughout the polymerization process and only performing a single solidification step at the end. This eliminates the need for repeated washing and precipitation cycles, reducing both time and process complexity while maintaining high catalytic activity through continuous effective catalysis
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 process achieves reproducible high yields, uniform morphology, and a narrower particle size distribution, enhancing the catalytic activity and polymer properties.
Implementation Method 1
reacting said complex in the solution form with a compound of a transition metal to produce a dispersion, wherein the dispersed phase predominantly contains the alkaline earth metal in said complex
Implementation Method 2
solidifying said dispersed phase to obtain said catalyst component
Data Source
AI summary
The present invention relates to particulate olefin polymerization catalyst components comprising an alkaline earth metal, a compound of a transition metal and an electron donor, characterized in that the catalyst particle size distribution of the catalyst component is essentially monomodal and has a SPAN value below 1.2, where SPAN is defined as: (Particle diameter at 90% cumulative size)−(Particle diameter at 10% cumulative size)/(Particle diameter at 50% cumulative size). The particulate olefin polymerisation catalyst components of the present invention are provided by a process which comprises preparing a solution of a complex of an alkaline earth metal and an electron donor by reacting a compound of said metal with said electron donor or a precursor thereof in an organic liquid reaction medium, reacting said complex in the solution form with a compound of a transition metal to produce a dispersion, wherein the dispersed phase predominantly contains the alkaline earth metal in said complex, and solidifying said dispersed phase to obtain said catalyst component, and is characterized in that a second organic liquid medium is added to the reactor after mixing the alkaline earth metal complex with the transition metal compound.