Polyimide Insulated Wire Adhesion and Permittivity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Insulated wires used in inverter-related equipment face a trade-off between low relative permittivity to prevent partial discharge and sufficient adhesion to the conductor, especially at high temperatures, due to the limitations of polyimide resins.
Innovation Solution
The use of a polyimide resin synthesized with specific amounts of 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 9,9-bis(4-aminophenyl)fluorene as diamine raw materials, with a imide group concentration of 25.0% or less, and incorporating tetracarboxylic dianhydride-derived units like pyromellitic anhydride and 3,3′,4,4′-biphenyltetracarboxylic dianhydride, to enhance adhesion and reduce relative permittivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the content of imide groups in the polyimide resin is reduced to suppress relative permittivity, then partial discharge deterioration is minimized, but adhesion force between the insulating film and conductor becomes insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the imide group concentration (25.0% or less) and the ratio of specific diamine-derived constituting units (1 to 40 mol %) to achieve optimal balance between low relative permittivity for partial discharge resistance and sufficient adhesion strength to the conductor
Solution Approach 2:
The patent uses composite material approach by incorporating specific diamine-derived constituting units (from 2,2-bis[4-(4-aminophenoxy)phenyl]propane and 9,9-bis(4-aminophenyl)fluorene) into the polyimide resin structure to create a composite polymer system that simultaneously provides low permittivity and high adhesion properties
2Object-affected harmful factors
If a polyimide resin with low relative permittivity is used for the insulating film, then partial discharge is prevented, but adhesion between the insulating film and conductor deteriorates, especially at high temperatures
Solution Approach 1:
The patent maintains adhesion reliability at high temperatures by controlling the imide group concentration at 25.0% or less while incorporating specific diamine-derived constituting units in a ratio of 1 to 40 mol %, creating a polyimide resin formulation that resists thermal degradation of adhesion
Solution Approach 2:
The patent applies local quality by creating specific chemical structures within the polyimide resin at the conductor interface through the use of diamine-derived constituting units, which provide localized adhesion enhancement without compromising the overall low permittivity property of the insulating film
Data Source
AI summary
An insulated wire, containing a conductor and an insulating film provided in contact with the conductor, in which the insulating film provided in contact with the conductor contains a polyimide resin, and the polyimide resin contains a constituting unit (A) derived from 2,2-bis[4-(4-amininophenoxy)phenyl]propane and a constituting unit (B) derived from 9,9-bis(4-aminophenyl)fluorene as a diamine-derived constituting unit; the polyimide resin has an imide group concentration of 25.0% or less; and the ratio of the content of the constituting unit (B) occupied in the diamine-derived constituting unit in the polyimide resin is 1 to 40 mol %.