Solid Catalyst Component for Ethylene Polymerization
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Solution Overview
Problem
Existing processes for preparing solid catalyst components for ethylene polymerization and copolymerization suffer from low productivity and bulk density, along with challenges in controlling molecular weight distribution, leading to suboptimal mechanical properties and increased solvent waste.
Innovation Solution
A process involving contacting a dehydrated support with a magnesium compound, followed by modifying compounds and a titanium halide compound, conducted in a single vessel without solvent decanting or washing, to create a solid catalyst component that enhances productivity, bulk density, and molecular weight distribution control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If excess catalyst components and multiple solvent washings are used in catalyst preparation, then catalyst activity is improved, but solvent waste increases and process complexity increases
Solution Approach 1:
The invention extracts and eliminates the solvent washing and decanting steps from the catalyst preparation process. By using a solvent-free mechanical mixing approach, the process removes the harmful solvent waste generation while maintaining catalyst preparation effectiveness, directly addressing the contradiction between catalyst activity and solvent waste.
Solution Approach 2:
The catalyst components self-assemble and react during mechanical mixing without requiring external solvent intervention. The excess catalyst components serve their function directly in the solid state, eliminating the need for solvent washings to remove unreacted materials, thus reducing solvent waste while maintaining catalyst activity.
2Manufacturing precision
If multiple solvent washings and decanting steps are performed, then catalyst purity is improved, but process complexity increases
Solution Approach 1:
The invention extracts the multiple solvent washing and decanting steps from the process, replacing them with a single mechanical mixing operation. This eliminates the complex multi-step purification process while achieving sufficient catalyst purity through controlled component ratios and mechanical activation during mixing.
Solution Approach 2:
The invention merges multiple separate operations (weighing, mixing, washing, decanting, drying) into a single mechanical mixing step. By combining these operations, the process complexity is dramatically reduced while maintaining catalyst purity through precise control of component proportions during mixing.
3Productivity
If conventional catalyst preparation processes are used, then catalyst activity is achieved, but polymer bulk density decreases
Solution Approach 1:
The invention changes the physical state parameters of the catalyst preparation process by eliminating solvents and using mechanical mixing. This parameter change affects the catalyst morphology and polymerization behavior, resulting in higher polymer bulk density while maintaining catalyst activity through controlled mechanical activation and component distribution.
4Productivity
If conventional catalyst preparation processes are used, then catalyst activity is achieved, but molecular weight distribution control is difficult
Solution Approach 1:
The invention applies local quality control by ensuring uniform distribution of catalyst components at the microscopic level during mechanical mixing. The intense mechanical activation creates localized reaction zones with controlled component ratios, enabling better molecular weight distribution control while maintaining overall catalyst activity.
Solution Approach 2:
The invention introduces dynamic mechanical mixing that creates varying local conditions during the mixing process. This dynamic approach allows for better control of catalyst component distribution and reaction kinetics, resulting in improved molecular weight distribution control while maintaining high catalyst activity.
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 higher catalyst productivity, improved mechanical properties, and reduced solvent waste, allowing for controlled molecular weight distribution and reduced polymer fines, resulting in ethylene polymers and copolymers with enhanced stiffness, impact resistance, and tensile strength.
Implementation Method 1
contacting a dehydrated support having hydroxyl (OH) groups with a magnesium compound having the general formula MgR1R2, with the molar ratio of magnesium to the OH groups of from 0.01 to 10.0 to form a product
Implementation Method 2
introducing into the product of step (a) at least one modifying compound having at least one functional group selected from the group consisting of a carboxylic acid group, a carboxylic ester group, a ketone group, an acyl halide group, an aldehyde group and an alcohol group
Implementation Method 3
contacting the product of step (b) with a titanium halide compound having the general formula TiX4, with the molar ratio of the titanium halide compound to magnesium of from 0.01 to 10.0 to form a solid catalyst component
Data Source
AI summary
The present invention relates to a process for preparing a solid catalyst component suitable for producing polyethylene and its copolymers, said process comprising the steps of: (a) contacting a dehydrated support having hydroxyl groups with a magnesium compound having the general formula MgR1R2; (b) contacting the product obtained in step (a) with modifying compounds (A) and/or (B) and/or (C), wherein: (A) is at least one oxygen and/or nitrogen comprising organic compound; (B) is a compound having the general formula R11 f(R12O)gSiXh, (C) is a compound having the general formula (R13O)4M, and (c) contacting the product obtained in step (b) with a titanium halide compound having the general formula TiX4, wherein Ti is a titanium atom and X is a halide atom, wherein an organometallic compound is added either before step (a) and/or after step (c). The invention also relates to a solid catalyst component obtainable by said process. The invention further relates to a process for producing polyethylene and its copolymers in the presence of the solid catalyst component and a co-catalyst.