Polyamide-imide Insulation Coating for Press-Formed Wires
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Solution Overview
Problem
Conventional polyamide-imide resin based insulating varnishes for enameled wires have poor flexibility, making them prone to damage and cracks during severe press-forming processes due to their rigid backbone, which limits their press-formability and breakdown voltage under high mechanical stresses.
Innovation Solution
A polyamide-imide resin based insulating varnish is synthesized with 5 to 50 mol % 2,4′-diphenylmethane-diisocyanate having a flexible molecular structure, combined with other isocyanates like 4,4′-diphenylmethane-diisocyanate, to enhance the flexibility and elongation properties of the insulation coating while maintaining thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyamide-imide resin with a rigid backbone is used to improve wear resistance and prevent cracks during press-forming, then the wear resistance is improved, but the flexibility and elongation properties deteriorate
Solution Approach 1:
The patent changes the chemical structure parameters of the polyamide-imide resin by introducing flexible aromatic diisocyanate components (specifically 2,4'-diphenylmethane-diisocyanate) into the rigid backbone structure. This modifies the molecular flexibility parameter while maintaining the fundamental polyamide-imide resin identity, thereby achieving both wear resistance and improved flexibility simultaneously
Solution Approach 2:
The patent creates a composite molecular structure within the polyamide-imide resin by combining rigid backbone segments with flexible aromatic diisocyanate segments. This composite approach allows the material to exhibit both the wear resistance of rigid structures and the flexibility of soft segments, resolving the contradiction between strength and flexibility
2Ease of manufacture
If the insulation coating is compressed to withstand severe press-forming processes, then the press-formability is improved, but the breakdown voltage decreases due to deformation beyond the limit
Solution Approach 1:
The patent changes the mechanical parameters of the insulation coating by modifying the resin's molecular structure to include flexible segments. This allows the coating to undergo larger elastic deformations during press-forming without permanent damage, maintaining breakdown voltage even after severe compression. The flexible structure enables the coating to recover from deformation rather than cracking
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 resulting insulated wire maintains a breakdown voltage higher than 60% of its original value even when compressed to half its diameter, demonstrating improved flexibility and press-formability without compromising thermal resistance.
Implementation Method 1
a polyamide-imide resin based insulating varnish synthesized by reaction of an isocyanate constituent and an acid constituent in a solvent
Data Source
AI summary
There is provided an insulated wire including: a conductor wire; and a polyamide-imide insulation coating formed around the conductor wire, the polyamide-imide insulation coating being made from a polyamide-imide resin based insulating varnish, the varnish being synthesized by reaction of an isocyanate constituent and an acid constituent in a solvent, the isocyanate constituent including 5 to 50 mol % of 2,4′-diphenylmethane-diisocyanate having a flexible molecular structure.