Debonding Bonded Articles Using Fatty Acid Solutions

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Solution Overview

Problem

Existing methods for debonding adhesively bonded articles are often complex, time-consuming, and can damage the substrates, especially when harsh chemicals or high temperatures are used.

Innovation Solution

A method involving a bonded article with layers of first and second adhesives, where a fibrous web is incorporated into the first adhesive layer, and a debonding solution in a polar solvent containing C10 to C26 fatty acids, their salts, or esters is used to treat the article, allowing for easy separation of the substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If mechanical processes such as sand blasting or wire brushing are used to remove adhesive, then the adhesive can be removed, but the substrate surfaces are corrupted and the process becomes complex

Engineering Contradiction:
Improveadhesive removalVSAvoidsubstrate surface corruption
Core Design Contradiction:
Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a primer layer as an intermediary substance between the substrate and the structural adhesive. This primer layer is specifically designed to be removable without damaging the substrate, serving as a sacrificial interface that allows clean separation of bonded substrates while leaving the valuable substrate surfaces intact.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesive bond system is segmented into two distinct layers: a permanent structural adhesive layer providing strong bonding, and a removable primer layer facilitating clean separation. This segmentation allows the system to simultaneously achieve strong bonding and easy, non-damaging disassembly.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If aggressive chemicals or high temperature are applied to separate substrates, then the substrates can be separated, but the substrates are damaged and become unsuitable for subsequent applications

Engineering Contradiction:
Improvesubstrate separationVSAvoidsubstrate damage
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The removable primer layer acts as a mediator that absorbs the separation process, allowing substrates to be detached without exposure to damaging chemicals or temperatures. The primer layer is chemically designed to respond to mild separation agents, protecting the substrate from direct contact with harsh separation methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The primer layer is formulated with specific chemical parameters that allow it to be selectively removed under controlled conditions. By changing parameters such as pH, solvent composition, or temperature within mild ranges, the primer layer can be removed while the substrate remains unaffected.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If aggressive chemicals or high temperature are used for debonding, then the adhesive bond can be broken, but the process becomes time consuming and complex

Engineering Contradiction:
Improveadhesive bond breakingVSAvoiddebonding time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The removable primer layer is applied in advance during the bonding process, pre-preparing the interface for future separation. This preliminary action embeds the separation mechanism within the bond structure itself, eliminating the need for complex post-bonding processing and reducing debonding time significantly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The primer layer serves as a built-in intermediary that provides a predetermined separation pathway. This allows debonding to occur through simple application of mild separation agents rather than requiring time-consuming aggressive chemical or thermal processes.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If a single layer of adhesive is used, then the bonding is strong, but the debonding process damages the substrates

Engineering Contradiction:
Improvebond strengthVSAvoidsubstrate damage during debonding
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The bonding system is divided into two functional layers: a permanent structural adhesive layer that provides strong, durable bonding, and a removable primer layer that facilitates clean separation. This segmentation allows the system to simultaneously achieve high bond strength and damage-free debonding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The removable primer layer acts as an intermediary between the substrate and the permanent adhesive, creating a sacrificial interface that protects the substrate during separation while maintaining the integrity of the primary bond.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method enables efficient and simple debonding of bonded articles without requiring harsh chemicals, elevated temperatures, mechanical abrasion, or significant force, while preserving the utility of the separated substrates for reuse or recycling.

Implementation Method 1

treating the bonded article with a debonding solution comprising a solvent and at least one compound selected from the group consisting of C10 to C26 fatty acids, salts of C10 to C26 fatty acids, and C1 to C4 alkyl esters of C10 to C26 fatty acids

Methodology Applied
Scientific EffectSolvation: Solvation

Implementation Method 2

a debonding solution in a polar solvent of a long chain fatty acid or a salt or ester

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Data Source

PatentEP4559671A1Method of separating bonded articles
Publication Date: 2025.05.28 HENKEL KGAA
  • EP4559671A1 patent drawingFigure 1~2
  • EP4559671A1 patent drawingFigure 3
  • EP4559671A1 patent drawing

AI summary

The present disclosure is directed to a method for debonding a bonded article, said method comprising the steps of: method for debonding a bonded article, said method comprising the steps of: a) providing a bonded article comprising at least one layer of a first adhesive interposed between two substrate surfaces, said bonded article being further provided with at least one layer of a second adhesive which is interposed between said two substrate surfaces, wherein: a fibrous web is at least partially incorporated into the or each layer of first adhesive; and, the or each layer of first adhesive has a dry film thickness of from 10 to 500 µm; b) treating the bonded article at a temperature of from 20 to 90°C with a solution in a polar solvent of at least one compound selected from the group consisting of: C10 to C26 fatty acids; salts of C10 to C26 fatty acids; and, C1-C4 alkyl esters of C10 to C26 fatty acids, wherein said solution has a pH of from 3 to 14; and, c) separating said at least one layer of first adhesive from its interposition between said two substrate surfaces.