Polyethylene Catalyst Preparation via Viscosity Control

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Solution Overview

Problem

Existing methods for preparing polyethylene polymerization catalysts face challenges in achieving uniform catalyst size and shape due to issues like cavitation during stirring and poor catalyst shape resulting from excessive solvent use.

Innovation Solution

The method involves adjusting the viscosity of a first mixed solution by adding a second hydrocarbon compound before introducing an internal electron donor, thereby controlling the catalyst shape and size during the recrystallization step.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If alcohol is used as a solvent to dissolve magnesium compound at high temperature for complete dissolution, then the magnesium compound dissolves completely, but cavitation occurs during stirring when temperature is lowered for recrystallization

Engineering Contradiction:

Improvedissolution completenessVSAvoidcavitation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a hydrocarbon solvent as an intermediary substance to mediate between the alcohol-magnesium compound system and the recrystallization process. The hydrocarbon solvent mixes with alcohol to form a mixed solvent system that reduces cavitation during temperature reduction while maintaining complete dissolution of magnesium compound, thus resolving the contradiction between complete dissolution and cavitation prevention

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical parameters of the solvent system by adjusting the composition ratio of alcohol and hydrocarbon solvent, and by controlling temperature parameters during the process. This parameter optimization allows complete dissolution at high temperature while preventing cavitation during cooling, resolving the contradiction through parameter control

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If additional solvent is added to prevent cavitation during stirring, then cavitation is prevented, but catalyst size increases and catalyst shape becomes poor

Engineering Contradiction:

Improvecavitation preventionVSAvoidcatalyst size and shape

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent optimizes the solvent composition parameters by using a specific ratio of alcohol to hydrocarbon solvent, and controls temperature parameters during the process. This parameter optimization prevents cavitation without requiring excessive solvent addition, thereby maintaining good catalyst size and shape

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a controlled amount of hydrocarbon solvent added to the alcohol system - not excessive solvent but a precise partial addition that is sufficient to prevent cavitation while avoiding the negative effects of excessive solvent on catalyst morphology

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If temperature and titration time are varied during recrystallization to control catalyst formation, then different catalyst sizes and shapes can be obtained, but it becomes difficult to obtain the desired size and shape due to too much variation

Engineering Contradiction:

Improvecatalyst size and shape controlVSAvoiddesired catalyst size and shape

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent systematically optimizes and controls the parameters of temperature and titration time within specific ranges, rather than allowing wide variations. This controlled parameter adjustment achieves the desired catalyst size and shape by finding the optimal parameter window that balances adaptability with precision

Inventive Principle:

Principle #35Parameter changes

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

This approach allows for the production of polyethylene polymerization catalysts with uniform size and excellent shape, reducing solvent usage and preventing cavitation, thus enhancing economic feasibility and polymer quality.

Implementation Method 1

a viscosity adjustment step of adding a second hydrocarbon compound to the first mixed solution to adjust a viscosity of the first mixed solution

Methodology Applied

Scientific EffectViscosity adjustment:

Implementation Method 2

a recrystallization step of adding a transition metal compound to the second mixed solution to perform recrystallization

Methodology Applied

Scientific EffectRecrystallization: Crystallisation

Implementation Method 3

when a temperature is lowered for recrystallization when using alcohol in order to completely dissolve magnesium chloride at a high temperature, cavitation may occur during stirring

Methodology Applied

Scientific EffectCavitation: Cavitation

Data Source

PatentUS20250115684A1Method for Preparing Polyethylene Polymerization Catalyst

Publication Date: 2025.04.10 SK INNOVATION CO LTD

AI summary

Provided is a method for preparing a polyethylene polymerization catalyst including a first mixed solution preparation step of mixing a magnesium compound, a first hydrocarbon compound, and alcohol to prepare a first mixed solution; a viscosity adjustment step of adding a second hydrocarbon compound to the first mixed solution to adjust a viscosity of the first mixed solution; a second mixed solution preparation step of adding a first internal electron donor to the first mixed solution having an adjusted viscosity to prepare a second mixed solution; and a recrystallization step of adding a transition metal compound to the second mixed solution to perform recrystallization.