Conductive 2K Epoxy Adhesive Sheet for Voltage-Triggered Debonding

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Solution Overview

Problem

Existing adhesive systems are difficult to disassemble without damaging the substrates, especially when electrical potential is applied, which is necessary for debonding, and they do not integrate well with conventional structural adhesives for composite structures.

Innovation Solution

An adhesive sheet comprising a first and second electrically conductive foil with a conductive and debondable 2K epoxy adhesive composition, containing an electrolyte, is used between the foils, allowing debonding by applying a voltage across the foils.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional structural adhesives are used for bonding composite structures, then strong bonding strength is achieved, but the bonded structures become difficult to disassemble without damaging substrates

Engineering Contradiction:
Improvebonding strengthVSAvoiddisassembly difficulty
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The adhesive system is segmented into two distinct parts: a conventional structural adhesive component and a debonding agent component. This segmentation allows the adhesive to provide strong bonding when combined, while enabling selective activation of the debonding function through controlled application of the second component or electrical stimulus, thus resolving the contradiction between bond strength and disassembly ease.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive system transitions from a static, permanently bonded state to a dynamic, controllable bonding state. By incorporating electroactive polymers or stimuli-responsive materials, the adhesive bonds can be dynamically activated or deactivated through electrical fields, allowing the structure to switch between bonded and debonded states as needed, thereby maintaining both strong bonding and ease of repair.

Inventive Principle:
Principle #15Dynamics

2Ease of repair

If mechanical processes like sand blasting or wire brushing are used to remove adhesive, then adhesive removal is achieved, but substrate surfaces are corrupted

Engineering Contradiction:
Improveadhesive removalVSAvoidsubstrate damage
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The invention replaces mechanical removal processes (sand blasting, wire brushing) with chemical or electrical debonding mechanisms. The debonding agent or electrical stimulus selectively breaks the adhesive bonds without mechanical contact to the substrate, eliminating the harmful mechanical effects while achieving complete adhesive removal for substrate reuse.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

A debonding agent or electrical field acts as an intermediary between the adhesive bond and the substrate. This intermediary selectively targets the adhesive material to break bonds without directly contacting or damaging the substrate surfaces, enabling clean separation and preserving substrate integrity for subsequent applications.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of repair

If aggressive chemicals or high temperature are applied to debond adhesive, then adhesive debonding is achieved, but substrates are damaged and become unsuitable for subsequent applications

Engineering Contradiction:
Improveadhesive debondingVSAvoidsubstrate damage
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The invention uses controlled changes in electrical field parameters or chemical composition parameters to achieve debonding. By precisely controlling the voltage, current, or chemical concentration, the debonding process occurs under mild conditions that selectively affect the adhesive without reaching the thresholds that would damage the substrate, thus enabling reuse of expensive substrates.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adhesive layer is designed as a disposable, sacrificial element that can be completely removed without affecting the permanent, valuable substrates. The adhesive serves its bonding function and then can be cleanly eliminated through the debonding mechanism, allowing the expensive substrates to be reused while the adhesive is replaced, effectively treating the adhesive as a consumable component.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Reliability

If adhesive bonds are used instead of mechanical fasteners, then stress distribution and sealing are improved, but disassembly becomes difficult when electrical potential is applied

Engineering Contradiction:
Improvestress distributionVSAvoiddisassembly under electrical potential
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The adhesive system is designed to perform multiple functions: it provides structural bonding with stress distribution like conventional adhesives, and simultaneously incorporates electroactive or chemically responsive properties that enable controlled debonding. This multi-functionality allows the same adhesive layer to serve both as a reliable structural bond and as a controllable, reversible connection, resolving the contradiction between reliability and operational flexibility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables effective bonding and easy debonding of composite structures by applying an electrical potential, preserving substrate integrity and facilitating repair, repurpose, and recycling of components.

Implementation Method 1

the electrolyte provides sufficient ionic conductivity to support a faradaic reaction at a bond formed between the composition and an electrically conductive surface

Methodology Applied
Scientific EffectFaradaic reaction: Electrolysis

Implementation Method 2

an electrically conductive and debondable 2K epoxy adhesive composition comprising a first part comprising: a) an epoxy resin; b) an electrically conductive filler

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4678390A1An adhesive sheet
Publication Date: 2026.01.14 HENKEL KGAA
  • EP4678390A1 patent drawingFigure 1~3
  • EP4678390A1 patent drawingFigure 4~5
  • EP4678390A1 patent drawingFigure 6

AI summary

The present invention is directed to an adhesive sheet for use in e-battery bonding comprising: a first electrically conductive foil; a second electrically conductive foil; and an electrically conductive and debondable 2K epoxy adhesive composition, wherein the electrically conductive and debondable 2K epoxy adhesive composition is disposed between the first and second conductive foils.