Conductive Two-Layer Adhesive for Mild Heat Debonding

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Solution Overview

Problem

Existing adhesive separation methods are harsh and damaging to substrates, requiring high temperatures and aggressive chemicals, making them unsuitable for delicate applications, and there is a need for a more precise and mild method to debond adhesives like polyurethanes, epoxies, and acrylates.

Innovation Solution

A heat separable two-layer adhesive system with conductive particles in one layer that can be separated by applying low electrical power, using resistive heating to locally heat the interface and loosen the adhesive layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional adhesive separation methods are used, then adhesive bonds can be broken, but substrates are damaged by harsh chemicals and high temperatures

Engineering Contradiction:

Improvesubstrate damageVSAvoidadhesive separation

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The invention changes the separation mechanism from chemical degradation to thermal softening by modifying the adhesive's glass transition temperature. The adhesive is formulated with Tg between -50°C and 50°C, allowing separation at mild temperatures (20-100°C) that do not damage substrates, while still achieving effective bond breaking through controlled thermal transitions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces harsh chemical separation methods with a thermal-mechanical approach. By using heat to soften the adhesive and enable mechanical separation, the system eliminates the need for aggressive chemicals while maintaining effective bond release capability through controlled thermal transitions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If high temperatures are applied to separate adhesives, then adhesive bonds are broken, but delicate substrates are damaged

Engineering Contradiction:

Improvesubstrate damageVSAvoidseparation temperature

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The invention fundamentally changes the temperature parameter for separation by formulating adhesives with specific glass transition temperatures (Tg between -50°C and 50°C). This allows separation to occur at mild temperatures (20-100°C) rather than requiring high temperatures, protecting delicate substrates while maintaining effective bond release through controlled thermal transitions.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If aggressive chemicals are used for adhesive separation, then adhesive bonds are broken, but substrate integrity is compromised

Engineering Contradiction:

Improvesubstrate damageVSAvoidadhesive separation

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The invention replaces chemical separation mechanisms with a thermal-mechanical approach. By using heat to soften the adhesive and enable mechanical separation, the system eliminates the need for aggressive chemicals while maintaining effective bond release capability through controlled thermal transitions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If thermally labile linkages are used in adhesives, then adhesive can be separated more easily, but harsh conditions are still required that damage substrates

Engineering Contradiction:

Improveadhesive separationVSAvoidsubstrate damage

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The invention optimizes the glass transition temperature parameter to a specific range (-50°C to 50°C) that enables easy separation at mild temperatures while preventing substrate damage. This precise parameter control allows the adhesive to be readily cleaved under gentle conditions that protect delicate substrates.

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 system allows for efficient and gentle separation of adhesives under mild conditions, reducing damage to substrates and enabling easy disassembly, repair, and recycling of bonded materials.

Implementation Method 1

subjecting the layer of first adhesive to a resistive heating, wherein the layer of first adhesive is locally heated

Methodology Applied

Scientific EffectResistive heating: Joule Heating

Data Source

PatentUS12448547B2Heat separable two-layer adhesive system and process of adhesive debonding using the same

Publication Date: 2025.10.21 HENKEL KGAA

AI summary

The present invention relates to a heat separable two-layer adhesive system, to a process of adhesive debonding using the adhesive system and to a heat separable bonded composite body. In particular, the present invention relates to a heat separable two-layer adhesive system comprising an adhesive layer having conductive particles.