Sandwich Panel Bonding with Non-Reactive Adhesive and Undercut Profile
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Solution Overview
Problem
The existing methods for producing sandwich panels are prone to undesirable bubble formation, especially at the profile edges where two panels are connected, due to thermal shocks and environmental influences.
Innovation Solution
A procedure for producing sandwich panels involves applying a non-reactive adhesive to the inner surface and the rear surface of the profile edge of the first cover layer, followed by the application of a self-expanding plastic material, which connects the two cover layers and reduces the risk of bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a reactive adhesive is applied to the outer layer of the sandwich panel, then the bond strength between the outer layer and foam core is improved, but the risk of blistering increases due to thermal shock and environmental influences
Solution Approach 1:
A non-reactive adhesive is applied in advance to the outer layer and the undercut surface of the profile edge before the foam core is applied. This preliminary adhesive layer creates a stable bonding interface that prevents blistering when thermal or mechanical stresses occur later during service.
Solution Approach 2:
The non-reactive adhesive acts as an intermediary substance between the outer layer and the foam core. It mediates the bonding interface, providing a stable transition zone that accommodates thermal expansion and contraction differences between the metal outer layer and the foam core, thereby preventing blistering while maintaining bond strength.
2Ease of manufacture
If adhesive is applied only to the large inner surface of the cover layer, then the application process is simplified, but the bond strength at the profile edge and undercut surface is insufficient
Solution Approach 1:
The adhesive application is differentiated by location: a non-reactive adhesive is specifically applied to the undercut surface and profile edge areas, while a different adhesive (reactive or non-reactive) is applied to the large inner surface. This local differentiation ensures optimal bonding strength at the critical profile edge while maintaining ease of application on the large surface area.
Solution Approach 2:
The adhesive bonding process is segmented into two distinct application zones: (1) application to the large inner surface of the cover layer, and (2) application to the undercut surface and profile edge. This segmentation allows each zone to receive the appropriate adhesive type and amount, optimizing both manufacturing ease and bonding strength at critical locations.
3Reliability
If the outer layer is used as the exterior of the sandwich panel, then the panel performance under environmental influences is improved, but the risk of blistering due to thermal shock increases
Solution Approach 1:
The non-reactive adhesive applied to the outer layer and profile edge acts as a cushioning layer before thermal shock occurs. This adhesive layer absorbs and distributes thermal stresses that arise during service, preventing the outer layer from detaching from the foam core and forming blisters, thereby maintaining panel performance under environmental influences.
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 use of non-reactive adhesive and self-expanding plastic material enhances the strength of the connection between the foam core and the cover layers, significantly reducing the risk of bubble formation and increasing the panel's resistance to environmental influences and thermal shocks.
Implementation Method 1
at least one self-expanding plastic material, in particular a foaming mass, is applied to the applied non-reactive adhesive; A second facing layer of the sandwich panel is positioned opposite the first facing layer at such a distance that the two facing layers are bonded together to form the sandwich panel by the expansion of the applied plastic material
Implementation Method 2
the non-reactive adhesive is applied by at least one laterally projecting nozzle to at least one undercut surface of the profile edge adjacent to the inner surface of the first cover layer, wherein the nozzle projects at least partially into the undercut
Data Source
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AI summary
The invention relates to a method for manufacturing a sandwich panel (10), in particular for buildings and/or freight transport, in which: - a first cover layer (11) of the sandwich panel (10) is fed to at least one adhesive application device (101) for large-area adhesive application, wherein the first cover layer (11) has a profile edge (12) extending in the feed direction (ZR) with at least one undercut (13); - a non-reactive adhesive (14) is applied by the adhesive application device (101) to an inner surface (15), in particular a large-area, of the first cover layer (11); and - the non-reactive adhesive (14) is applied by at least one laterally projecting nozzle (102) to at least one undercut surface (16) of the profile edge adjacent to the inner surface (15) of the first cover layer (11), wherein the nozzle (102) projects at least partially into the undercut;- at least one self-expanding plastic material (17), in particular a foaming mass, is applied to the applied non-reactive adhesive (14); - a second cover layer (18) of the sandwich panel (10) is positioned opposite the first cover layer (11) at a distance such that the two cover layers (11, 18) are joined together to form the sandwich panel (10) by expansion of the applied plastic material (17).