Propylene Random Copolymer Catalyst Surface Area Control
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Solution Overview
Problem
Propylene homopolymers have high heat and chemical resistance but lack impact strength, flexibility, and clarity, which are improved by copolymerizing with ethylene or α-olefins, but high comonomer content leads to stickiness and fouling issues in polymerization processes, affecting reactor efficiency and product quality.
Innovation Solution
A process using a catalyst system with solid catalyst particles having a specific surface area less than 20 m²/g, comprising transition metal compounds and metal compounds from specific groups of the periodic table, without catalytically active sites or external support, to produce propylene random copolymers with high comonomer content while minimizing stickiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high comonomer content is incorporated into propylene copolymer to improve impact strength and flexibility, then mechanical properties are improved, but the polymer becomes sticky and causes fouling in reactor and transfer lines
Solution Approach 1:
The invention changes the physical-chemical parameters of the catalyst system by using solid catalyst particles with specific surface area less than 20 m²/g and incorporating inclusions that modify the polymerization environment. This parameter change allows high comonomer incorporation while controlling polymer stickiness and preventing fouling
Solution Approach 2:
The inclusions within the solid catalyst particles act as intermediaries that mediate between the catalyst active sites and the polymerization environment. These inclusions modify local conditions to enable high comonomer content while maintaining low stickiness and preventing fouling
2Object-generated harmful factors
If antistatic agents are added to reduce polymer stickiness and fouling, then adherence to reactor walls is reduced, but catalytic activity is lowered due to adsorption on catalyst surface
Solution Approach 1:
The inclusions within the solid catalyst particles serve as intermediaries that reduce polymer stickiness and fouling without requiring external antistatic agents. This intermediary structure prevents harmful interactions between the polymer and reactor surfaces while maintaining catalyst activity
Solution Approach 2:
The invention extracts the need for antistatic agents by incorporating functional inclusions within the catalyst particles themselves. This eliminates the harmful side effect of catalyst deactivation while still achieving the desired reduction in polymer stickiness and fouling
3Strength
If comonomers are randomly distributed in polymeric chain to improve mechanical and optical properties, then propylene random copolymer is obtained, but at high comonomer content comonomers build separate building blocks reducing randomness
Solution Approach 1:
The invention changes the catalyst system parameters by using solid particles with specific surface area less than 20 m²/g and incorporating inclusions, which creates a polymerization environment that maintains random comonomer distribution even at high comonomer content (1.5-10.0 wt.-%)
Solution Approach 2:
The inclusions within the catalyst particles create local zones with modified properties that favor random comonomer incorporation. This local quality modification ensures uniform random distribution throughout the polymer chain while maintaining high comonomer content
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 high randomness and low stickiness in propylene random copolymers, reducing fouling risks and maintaining process flexibility and yield, enabling the incorporation of high comonomer content without compromising polymer properties.
Implementation Method 1
in the presence of a catalyst system comprising solid catalyst particles
Data Source
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AI summary
A process for the preparation of a propylene random copolymer, wherein propylene is polymerised with ethylene and/or a C4-C20 alpha-olefin in the presence of a catalyst system comprising solid catalyst particles, wherein the solid catalyst particles (a) have a specific surface area of less than 20 m2 /g, (b) comprise a transition metal compound which is selected from one of the groups 4 to 10 of the periodic table or a compound of actinide or lanthanide,10 (c) comprise a metal compound which is selected from one of the groups 1 to 3 of the periodic table, and (d) comprise inclusions not having catalytically active sites.