Modified Polyamide-Imide Resin for Insulated Conductor Adhesiveness

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Solution Overview

Problem

Insulating films on conductors in high-temperature environments face adhesiveness issues due to conductor oxidation and the volatility of reducing agents used to maintain adhesiveness, leading to a loss of oxidation suppression effect over time.

Innovation Solution

A resin comprising modified polyamide-imide and polyimide compounds with terminal OH or SH groups, which have high reducing power and stability, are used to form insulating films with excellent adhesiveness, achieved through specific molecular weight ranges and bonding methods, and applied using varnishes or electrodeposition dispersions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a reducing agent is added to insulating paint to suppress conductor oxidation, then adhesiveness is improved, but the reducing agent volatilizes over time causing loss of oxidation suppression effect

Engineering Contradiction:

ImproveadhesivenessVSAvoidreducing agent volatilization

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the chemical parameters of the reducing agent by using polyfunctional reducing agents with specific molecular structures (containing multiple OH groups, SH groups, or NH2 groups) and controlling their molecular weight and functional group content. This transforms the volatile simple reducing agents into non-volatile polymeric reducing agents that maintain long-term effectiveness.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite insulating film system where the resin contains both the film-forming component and the reducing agent component integrated into a single polymeric structure. This composite approach allows the reducing agent function to be permanently embedded in the insulating film matrix, preventing volatilization while maintaining oxidation suppression capability.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If conventional reducing agents are used to maintain adhesiveness in high temperature environments, then oxidation suppression is improved, but the reducing agents gradually volatilize leading to loss of effect

Engineering Contradiction:

Improveconductor oxidationVSAvoidreducing agent effectiveness duration

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

The patent replaces the short-living volatile reducing agents with long-living polymeric reducing agents that are integrated into the insulating film structure. These polymeric reducing agents have such low volatility that they effectively become permanent, providing lifelong oxidation protection rather than temporary protection.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If insulating film is formed with reducing agents to prevent conductor oxidation, then adhesiveness is improved, but long-term storage in high temperature causes reducing agent loss

Engineering Contradiction:

ImproveadhesivenessVSAvoidreducing agent stability

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent incorporates the reducing agent function into the insulating film formation process itself, rather than adding it separately afterward. The polyfunctional reducing agents are integrated into the resin structure before film formation, ensuring they are permanently embedded and cannot volatilize during subsequent storage or service.

Inventive Principle:

Principle #10Preliminary action

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 resin ensures sustained adhesiveness and oxidation suppression for conductors even after long-term storage in high-temperature environments, with the modified polyamide-imide and polyimide compounds maintaining their effectiveness by preventing volatilization and maintaining film integrity.

Implementation Method 1

suppress the oxidation of the conductor

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

heating the coating layer to produce an insulating film and bake the insulating film on the conductor

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

the coating layer is heated to produce an insulating film

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3715427B1Resin for forming insulating coating film, varnish, electrodeposition liquid, and method for producing insulated conductor

Publication Date: 2023.03.15 MITSUBISHI MATERIALS CORP

AI summary

A resin for forming an insulating film includes at least one of a modified polyamide-imide having a terminal OH group or a terminal SH group and a modified polyimide having a terminal OH group or a terminal SH group. A varnish includes the resin for forming an insulating film and a solvent. An electrodeposition dispersion includes the resin for forming an insulating film, a polar solvent, water, a poor solvent, and a base. A method for producing an insulated conductor includes: a step of applying the varnish or electrodepositing the electrodeposition dispersion to a surface of a conductor to form a coating layer or an electrodeposition layer on the surface of the conductor; and a step of heating the coating layer or the electrodeposition layer to produce an insulating film and bake the insulating film on the conductor.