Polyimide Insulated Wire for Strong Interlayer Adhesion
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Solution Overview
Problem
Existing insulated wires face challenges in maintaining high adhesiveness between the layers of the insulation film due to reduced entanglement of polymer components when inorganic fillers are added, leading to decreased molecular bonding and increased residual stress.
Innovation Solution
Incorporating polyimide and an inorganic filler into the insulation film, with specific ratios of raw materials like PMDA, ODA, BPDA, TPE-R, and BODA, to achieve a storage modulus of 0.9 GPa or less at 370°C, thereby reducing residual stress and enhancing adhesiveness between the film layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic filler is blended into the insulation film to increase surge resistance, then surge resistance is improved, but adhesiveness between layers is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the polyimide by specifying precise molar ratios of diamine components (ODA: 30-70 mol%, BODA: 10-40 mol%, TPE-R: 5-20 mol%). This compositional adjustment modifies the polymer's molecular structure and intermolecular forces, enabling the insulation film to maintain high adhesiveness (≥8.0 N/10mm) even with inorganic filler content of 1-10 phr, thus resolving the contradiction between surge resistance and layer adhesiveness
Solution Approach 2:
The patent creates a composite insulation film by blending polyimide with inorganic fillers (such as silica, alumina, or titanium oxide) at controlled concentrations (1-10 phr). The specific polyimide composition acts as a matrix that binds the inorganic filler particles while maintaining strong interlayer adhesion. This composite structure achieves both improved surge resistance from the inorganic filler and maintained adhesiveness through the optimized polyimide matrix
2Device complexity
If polymer components on the interface between layers decrease, then molecular entanglement decreases, but adhesiveness between layers is reduced
Solution Approach 1:
The patent adjusts the chemical parameters of the polyimide by controlling the diamine component ratios, which directly affects the polymer's molecular weight, chain flexibility, and intermolecular bonding capacity. This optimization ensures sufficient polymer components remain at the layer interface to maintain strong adhesiveness while achieving the required surge resistance performance
Data Source
AI summary
An insulated wire having high adhesiveness between layers forming an insulation film is provided. The insulated wire of the present disclosure includes a conductor, and the insulation film that coats the conductor. The insulation film includes polyimide and an inorganic filler. A storage modulus of the insulation film at 370° C. is 0.9 GPa or less.