Thermally Debondable Epoxy Adhesive for Clean Substrate Separation

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Solution Overview

Problem

Existing adhesive compositions used in e-mobility components are difficult to debond without damaging the substrates, especially in applications requiring disassembly, and current debonding methods like mechanical or chemical processes can be time-consuming and harmful to the substrates.

Innovation Solution

A thermally debondable two-component epoxy adhesive composition comprising an epoxy resin, reactive diluents, thermally expandable thermoplastic microspheres, and a mixture of curing agents, which can be activated by heat to weaken the bond effectively while maintaining adhesion and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If high temperature is applied to debond adhesive bonds, then debonding efficacy is improved, but substrate damage occurs

Engineering Contradiction:

Improvedebonding efficacyVSAvoidsubstrate damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The adhesive composition is formulated with specific epoxy resins, curing agents, and fillers that change their bonding characteristics at elevated temperatures. The adhesive maintains strong bonding at room temperature but exhibits reduced adhesion strength at debonding temperatures (80-150°C), enabling effective debonding without excessive heat that would damage substrates.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The adhesive is a composite material containing epoxy resin, curing agent, and carefully selected fillers that provide thermal stability and controlled debonding behavior. This composite structure allows the adhesive to withstand curing temperatures while enabling clean debonding at moderate temperatures without substrate damage.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If mechanical processes are used to remove adhesive, then debonding is achieved, but substrate surfaces are corrupted

Engineering Contradiction:

Improvedebonding capabilityVSAvoidsubstrate surface integrity

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The invention replaces mechanical removal processes (sand blasting, wire brushing) with a thermal debonding mechanism. The adhesive is formulated to debond through controlled thermal expansion and reduced adhesion strength at elevated temperatures, eliminating the need for mechanical abrasion that would damage substrate surfaces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If chemical processes are used to remove adhesive, then debonding is achieved, but time consumption and complexity increase

Engineering Contradiction:

Improvedebonding capabilityVSAvoiddebonding time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The invention replaces chemical debonding processes with a controlled thermal debonding mechanism. The adhesive contains fillers and is formulated to respond predictably to heat, enabling rapid debonding through thermal expansion and reduced bonding strength, thereby reducing the time and complexity associated with chemical removal processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Strength

If strong adhesive bonds are used to maintain adhesion during impact events, then bonding strength is improved, but debonding difficulty increases

Engineering Contradiction:

Improveadhesion strengthVSAvoiddebonding ease

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The adhesive exhibits dynamic bonding characteristics that change with temperature. At room temperature and during impact events, the adhesive provides strong bonding to withstand mechanical stresses. When heated to debonding temperatures (80-150°C), the adhesive's bonding strength reduces due to thermal expansion, softening of the polymer matrix, and reduced interfacial adhesion, enabling easy separation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The adhesive formulation includes specific epoxy resins, curing agents, and fillers that create a bonding system with temperature-dependent properties. The adhesive maintains high strength at operating temperatures but undergoes controlled parameter changes at debonding temperatures, reducing adhesion strength to enable clean separation without substrate damage.

Inventive Principle:

Principle #35Parameter changes

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 allows for easy debonding of substrates at controlled temperatures without damaging them, providing improved adhesion, thermal isolation, and maintaining substrate integrity.

Implementation Method 1

thermally expandable thermoplastic microspheres

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4696730A1A thermally debondable two-component epoxy adhesive composition

Publication Date: 2026.02.18 HENKEL KGAA

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Figure 3

AI summary

The present invention relates to a thermally debondable two-component epoxy adhesive composition comprising a first part comprising an epoxy resin; a mixture of two or more reactive diluents; and thermally expandable thermoplastic microspheres; and a second part comprising mixture of three or more curing agents consisting of at least one compound possessing at least two epoxide reactive groups per molecule; an accelerator; and, a catalyst, wherein the first part and the second part are mixed in epoxy:NH2 equivalent ratio of from 0.95:1 to 1:0.95.