Compatibilized PP Capacitor Film for High-Temperature Breakdown Strength
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Solution Overview
Problem
Existing polypropylene capacitor compositions sacrifice mechanical properties and electrical breakdown strength to achieve higher temperature resistance, failing to meet the demands of advanced inverter applications.
Innovation Solution
A polypropylene composition comprising 70-95 wt.% high isotactic homopolymer, 2.5-30 wt.% cyclic olefin polymer, and 0.1-2.5 wt.% random propylene copolymer compatibilizer, optimized through melt-blending to enhance dispersion and maintain mechanical and electrical properties at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polypropylene is blended with cyclic olefin polymer to increase temperature resistance, then the maximum operating temperature improves, but mechanical properties and electrical breakdown strength deteriorate
Solution Approach 1:
A compatibilizer comprising a random copolymer of propylene and ethylene is introduced as an intermediary substance between the polypropylene matrix and cyclic olefin polymer domains. The compatibilizer contains reactive functional groups that form intermolecular bonds with both phases, creating a bridging effect that improves interfacial adhesion. This mediator prevents the deterioration of mechanical properties and electrical breakdown strength while maintaining the temperature resistance benefits of the cyclic olefin polymer blend.
Solution Approach 2:
The invention creates a multi-phase composite material system consisting of polypropylene matrix, cyclic olefin polymer dispersed domains, and compatibilizer at the interface. This composite structure leverages the high temperature resistance of cyclic olefin polymers while using the compatibilizer to maintain the mechanical integrity and electrical properties of the overall material, achieving a synergistic effect that resolves the contradiction between temperature resistance and strength.
2Reliability
If polypropylene is blended with cyclic olefin polymer to achieve higher temperature resistance, then durability at high temperature improves, but electrical breakdown strength deteriorates
Solution Approach 1:
The compatibilizer with reactive functional groups acts as an intermediary that improves interfacial adhesion between polypropylene and cyclic olefin polymer phases. This enhanced interfacial bonding prevents premature failure under electrical stress at high temperatures, thereby maintaining electrical breakdown strength while achieving improved durability through the cyclic olefin polymer content.
3Temperature
If polypropylene is blended with cyclic olefin polymer to increase temperature resistance, then thermal stability improves, but mechanical strength deteriorates
Solution Approach 1:
The compatibilizer comprising random copolymer of propylene and ethylene with reactive functional groups serves as a mediator that forms intermolecular bonds between the polypropylene matrix and cyclic olefin polymer domains. This interfacial bonding maintains mechanical strength by preventing phase separation and ensuring stress transfer, while allowing the cyclic olefin polymer to contribute to thermal stability.
Solution Approach 2:
The multi-phase composite structure combines polypropylene, cyclic olefin polymer, and compatibilizer to achieve both thermal stability and mechanical strength. The compatibilizer ensures proper dispersion and interfacial adhesion, creating a synergistic composite material that exhibits both improved thermal stability from the cyclic olefin polymer and maintained mechanical strength through effective interfacial bonding.
Data Source
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AI summary
The present invention relates to a composition comprising 70 to 95 wt.-% of a high isotactic homopolymer of propylene, more than 2.5 to less than 30 wt.-% of a cyclic olefin polymer composition, and 0.1 to 2.5 wt.-% of a random propylene copolymer compatibilizer. The present invention is, furthermore, directed to a film comprising the polypropylene composition. Apart from that, a biaxially oriented film comprising the polypropylene composition and a capacitor are provided.