Ziegler-Natta Catalyst Component Impurity Resistance

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Solution Overview

Problem

Conventional high-activity supported Ziegler-Natta catalysts for olefin polymerization are not suitable for producing polypropylene and copolymers of ethylene and propylene, and they lack impurity resistance, leading to higher production costs and polymer fines.

Innovation Solution

A catalyst component comprising magnesium, titanium, halogen, an inner electron donor, and an alkoxy group from a surface modifier, prepared by dissolving magnesium in an organic epoxy and phosphorus compound mixture, treating with titanium in the presence of an auxiliary precipitant, and modifying with a surface modifier to achieve high catalytic activity and impurity resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional high-activity supported Ziegler-Natta catalysts are used for olefin polymerization, then catalytic activity is improved, but impurity resistance deteriorates and polymer fines increase

Engineering Contradiction:

Improvecatalytic activityVSAvoidimpurity resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent uses a composite catalyst system comprising magnesium halide support, titanium halide active centers, and multiple electron donor compounds (inner and outer sphere donors). This composite structure combines the high activity of supported Ziegler-Natta catalysts with improved impurity resistance through the synergistic interaction of multiple components, particularly the electron donors that enhance catalyst selectivity and reduce sensitivity to impurities

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces different types of electron donor compounds with specific functions at different locations in the catalyst structure. Inner sphere electron donors (e.g., esters, ethers) are coordinated to titanium centers to modify electronic properties, while outer sphere electron donors (e.g., silanes, borates) operate in the vicinity to influence polymerization kinetics and selectivity, creating localized functional zones that simultaneously enhance activity and impurity resistance

Inventive Principle:

Principle #3Local quality

2Productivity

If conventional catalysts are used for polypropylene and copolymer production, then production cost increases due to lack of impurity resistance, but catalyst activity is maintained

Engineering Contradiction:

Improvecatalyst activityVSAvoidproduction cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent optimizes multiple parameters including the types and ratios of electron donor compounds, titanium to magnesium ratio, halide composition, and preparation conditions (temperature, solvent, precipitation rate). These parameter changes create a catalyst with enhanced impurity resistance that reduces polymer fines and simplifies downstream processing, thereby lowering production costs while maintaining high catalytic activity

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If catalysts with broad molecular weight distribution are produced, then polymer quality is improved, but particle size control becomes more difficult

Engineering Contradiction:

Improvemolecular weight distributionVSAvoidparticle size distribution

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent creates different types of active centers on the catalyst surface through the use of electron donor compounds with varying steric and electronic properties. This results in multiple polymerization sites that produce chains with different growth rates and termination behaviors, generating a broad molecular weight distribution. Simultaneously, the supported structure on magnesium halide provides geometric constraints that maintain uniform particle morphology and size distribution

Inventive Principle:

Principle #3Local quality

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 exhibits high catalytic activity, narrow particle size distribution, and improved polymer morphology, reducing production costs and fines, making it suitable for impact-resistant propylene copolymers and BOPP film-grade resins.

Implementation Method 1

dissolving a magnesium halide in a solvent mixture consisting of an organic epoxy compound and an organic phosphorus compound to form a homogeneous solution

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 2

mixing the solution with a titanium tetrahalide or its derivatives; precipitating a solid

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS7388060B2Catalyst component for olefin (co)polymerization, preparation thereof, a catalyst comprising the same and use thereof

Publication Date: 2008.06.17 CHINA PETROLEUM & CHEMICAL CORP

AI summary

The invention relates to a catalyst component for olefin (co)polymerization, to preparation thereof, to a catalyst comprising the same, and to use thereof in olefin (co)polymerization. The catalyst component of the invention comprises magnesium, titanium, halogen, inner electron donor compound, and alkoxy group derived from a surface modifier, wherein the content of the alkoxy group derived from the surface modifier is in a range of from 0.01 to 3 percent by weight, based on the weight of the catalyst component.