Selfbonding Enamel Resins for Wire Coating Thermal Stability

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Solution Overview

Problem

Conventional selfbonding enamels for electrically conductive wires have low re-softening temperatures and limited fixing properties, and often require two-component formulations or blocked isocyanates that can cause emissions and blistering effects, leading to decreased sticking power and limited re-softening temperature ranges.

Innovation Solution

A selfbonding enamel composition comprising 5-95 wt% of resins with nucleophilic groups, 0-70 wt% amide group-containing resins, 0-30 wt% polyurethane resin, and 0-30 wt% epoxy resin, with α-carboxy-β-oxocycloalkyl carboxylic acid amide groups for crosslinking, providing excellent adhesion and high re-softening temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional selfbonding enamels are used, then adhesion on coated surfaces is achieved, but re-softening temperatures are low and fixing properties are limited

Engineering Contradiction:
Improvere-softening temperatureVSAvoidfixing properties
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses composite materials by combining polyester amide imides with polyester amides and polyurethane resins in specific ratios. This composite approach creates a selfbonding enamel that achieves both high re-softening temperatures (above 200°C) and excellent fixing properties through the synergistic interaction of multiple resin components with different thermal and bonding characteristics.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters by incorporating 5-95 wt% polyester amide imide, 0-70 wt% polyester amide, and 0-30 wt% polyurethane resin. This parameter optimization enables the enamel to maintain adhesion while achieving superior thermal stability and fixing properties, resolving the contradiction between temperature resistance and bonding reliability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If blocked isocyanates are used as curing agents, then crosslinking is achieved, but emissions and blistering effects occur leading to decreased sticking power

Engineering Contradiction:
Improvesticking powerVSAvoidemissions and blistering effects
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful blocked isocyanate curing agent from the system. Instead, it uses a self-crosslinking mechanism based on polyester amide imides that react with polyester amides through nucleophilic attack, forming a crosslinked network without requiring external curing agents. This removes the source of emissions and blistering while maintaining reliable sticking power.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements self-service by enabling the polyester amide imide to crosslink with itself and with polyester amide components without needing external curing agents. The resin system performs its own curing function through internal chemical reactions, eliminating harmful by-products and maintaining consistent sticking power throughout the coating.

Inventive Principle:
Principle #25Self-service

3Reliability

If thermosetting selfbonding enamels with curing agents are used, then crosslinking is achieved, but re-softening temperature range is limited

Engineering Contradiction:
ImprovecrosslinkingVSAvoidre-softening temperature range
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the temperature parameters by formulating an enamel that maintains re-softening temperatures above 200°C while achieving crosslinking. The specific combination of polyester amide imide (5-95 wt%) with polyester amide (0-70 wt%) and polyurethane resin (0-30 wt%) creates a crosslinked structure that remains flexible and re-softens at high temperatures, expanding the usable temperature range.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials combining multiple resin systems that work synergistically to achieve both crosslinking and high re-softening temperatures. The polyester amide imide provides crosslinking capability while the polyester amide and polyurethane components contribute to thermal stability and flexibility, resulting in a broad re-softening temperature range.

Inventive Principle:
Principle #40Composite materials

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 composition achieves high adhesion on coated surfaces, stable storage, and excellent heat shock resistance with improved electrical, thermal, and mechanical properties, while maintaining high enamelling speed and surface quality.

Implementation Method 1

resins with nucleophilic groups as well as possibly amide group-containing resins which are capable of crosslinking with one another

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

the resins of either component (A) and/or, if component (B) is contained in the composition, component (B) contain α-carboxy-β-oxocycloalkyl carboxylic acid amide groups

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentUS9006350B2Selfbonding enamels based on new polyester amide imides and polyester amides
Publication Date: 2015.04.14 AXALTA COATING SYSTEMS IP CO LLC

AI summary

A selfbonding enamel containing resins which are capable of crosslinking with one another, comprising(A) 5 to 95 wt % of at least one resin with nucleophilic groups selected from the group consisting of OH, NHR, SH, C(O)NHR, carboxylate, CH-acidic groups and Carbanions,(B) 0 to 70 wt % of at least one amide group-containing resin and(C) 0 to 30 wt % of at least one polyurethane resin,(D) 0 to 30 wt % of at least one epoxy resin,(E) 5 to 95 wt % of at least one organic solvent,wherein the resins of either component (A) and/or, if component (B) is contained in the composition, component (B) contain α-carboxy-β-oxocycloalkyl carboxylic acid amide groups the coatings of the selfbonding enamel have excellent adhesion to electrically conductive wires high sticking properties and high re-softening temperatures.