Shape Memory Structural Adhesive for Cavity Reinforcement

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Solution Overview

Problem

Existing reinforcing elements for hollow structural components impair the mechanical properties of structural adhesives during the foaming process, and they struggle to effectively close the gap between the cavity and the reinforcing element without compromising adhesive properties.

Innovation Solution

A composition comprising a curable structural adhesive and a chemically cross-linked elastomer, where the elastomer forms a penetrating polymer network, is used to create shape memory materials that can expand in a desired direction without foaming, thus maintaining the mechanical properties of the adhesive.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If reinforcing elements are inserted into hollow structural components to improve mechanical properties, then strength and stability are improved, but the mechanical properties of the structural adhesive are impaired during the foaming process

Engineering Contradiction:
Improvemechanical properties of reinforcing elementVSAvoidmechanical properties of structural adhesive
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent extracts the harmful foaming process from the reinforcement installation sequence. The reinforcing element is installed and bonded to the structural component before the foaming process occurs. The structural adhesive is applied in an unfoamed state, allowing the reinforcing element to be properly bonded without the mechanical properties being impaired by subsequent foaming. The gap closing is achieved through the adhesive's bonding capability rather than through foaming expansion.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If structural foams are used to reinforce hard-to-reach areas after assembly, then accessibility is improved, but the mechanical properties of the structural adhesive are impaired during the foaming process

Engineering Contradiction:
Improveaccessibility for reinforcementVSAvoidmechanical properties of structural adhesive
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies preliminary action by installing the reinforcing element and applying the structural adhesive in an unfoamed state before the foaming process. This sequence allows the adhesive to bond properly to the reinforcing element and structural component without the mechanical properties being compromised by the foaming process. The adhesive is applied preliminarily when it has optimal bonding characteristics, and the foaming occurs afterward to provide the necessary expansion and sealing.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If the gap between the cavity and reinforcing element is closed using traditional methods, then sealing is improved, but the mechanical properties of the structural adhesive are impaired

Engineering Contradiction:
Improvesealing of gapVSAvoidmechanical properties of structural adhesive
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent replaces the mechanical foaming expansion method with a chemical bonding method. Instead of relying on the adhesive to expand and fill the gap mechanically through foaming, the solution uses the adhesive's chemical bonding capability to close and seal the gap. The structural adhesive forms strong chemical bonds with both the reinforcing element and the structural component, providing effective sealing without the need for foaming expansion that would compromise adhesive properties.

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

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

This solution allows for the closure of the gap between the cavity and the reinforcing element without impairing the mechanical properties of the structural adhesive, enhancing the stability and strength of hollow structural components.

Implementation Method 1

compositions according to the invention can be used to produce shape memory materials which change their shape, in particular due to the influence of temperature, and thus expand in a desired direction without being accompanied by an increase in volume

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Polymer

Implementation Method 2

at least one chemically cross-linked elastomer; where the chemically cross-linked elastomer is present as a penetrating polymer network in the structural adhesive

Methodology Applied
Scientific EffectChemical cross-linking: Chemical Bonding

Implementation Method 3

at least one curable structural adhesive

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP2553035B2Shape memory material on the basis of a structural adhesive
Publication Date: 2025.06.18 SIKA TECH AG
  • EP2553035B2 patent drawingFigure 1~3
  • EP2553035B2 patent drawingFigure 4~5
  • EP2553035B2 patent drawingFigure 6

AI summary

The present invention relates to a composition comprising a) at least one curable structural adhesive, as well as b) at least one chemically cross-linked elastomer, wherein the elastomer is present as a penetrating polymer network in the structural adhesive. Such a composition constitutes a so-called shape memory material and is suitable for reinforcing cavities in structural components, such as for example in automobile bodies.