Polyamic Acid Conductor Coating for Flexible Corona-Resistant Insulation
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Solution Overview
Problem
Existing insulating layers for high-voltage electrical devices face challenges with low flexibility and heat resistance, leading to potential dielectric breakdown and partial discharge, which shortens the lifespan of the devices.
Innovation Solution
A polyamic acid composition is developed, incorporating specific diamine and dianhydride monomers, including a diamine monomer with a specific structure that enhances adhesion and flexibility while preventing dielectric breakdown and partial discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyimide resin with rigid structure is used to achieve heat resistance and low dielectric constant, then insulation and heat resistance are improved, but flexibility and tensile elongation are reduced
Solution Approach 1:
The patent changes the chemical structure parameters of the diamine monomer by introducing flexible alkylene groups (such as -CH2-CH2-CH2-) between aromatic rings, while maintaining the polyimide resin's heat resistance and low dielectric constant properties. This structural parameter modification enables the resin to achieve both rigidity for thermal stability and flexibility for mechanical deformation without compromising insulation performance
Solution Approach 2:
The patent creates a composite molecular structure by combining rigid aromatic dianhydride units with flexible aliphatic diamine units containing ether groups or alkylene chains. This composite approach at the molecular level allows the polyimide resin to exhibit both the heat resistance of aromatic structures and the flexibility of aliphatic chains, resolving the contradiction between rigidity and flexibility
2Ease of operation
If flexible structures are introduced to improve flexibility, then ease of processing is improved, but heat resistance is reduced
Solution Approach 1:
The patent carefully controls the parameters of flexible groups by using specific diamine monomers where aromatic rings (providing heat resistance) are connected by limited-length alkylene chains (providing flexibility). The flexible segments are constrained in size and placement to prevent excessive chain mobility that would reduce thermal stability, thus maintaining heat resistance while achieving necessary flexibility
Solution Approach 2:
The patent introduces flexibility locally at specific positions within the polymer chain by incorporating diamine monomers with flexible linkages between aromatic rings. The rigid aromatic dianhydride units maintain heat resistance at critical locations, while the flexible diamine segments provide localized flexibility. This spatial differentiation of properties allows simultaneous achievement of heat resistance and flexibility
3Reliability
If dielectric constant is lowered to prevent corona discharge, then reliability under high voltage is improved, but adhesion to conductor may be reduced
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating diamine monomers with heteroatoms (oxygen in ether groups) that reduce dielectric constant and improve corona resistance. Simultaneously, the patent ensures adhesion by maintaining appropriate functional groups that can form strong bonds with conductor surfaces, thus achieving both low dielectric constant for corona protection and sufficient adhesion strength
Data Source
AI summary
The present invention relates to a polyamic acid composition for coating a conductor, and provides a polyamic acid composition for coating a conductor that prevents dielectric breakdown and partial discharge of a cured product while improving adhesion between a conductor and a coating material and flexibility of the coating material.