Composite Metallic Panel Fire Safety Bonding
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Solution Overview
Problem
Metallic cladding panels in building construction face challenges in fire safety and bond strength, particularly in meeting higher fire safety standards like EN 13501-6:2018 classification A1, and maintaining adhesion without delamination.
Innovation Solution
A composite metallic panel comprising metallic sheets with a silicone-based primer coating and an organosilicon adhesive, which has a gross heat of combustion of no greater than 1.4 MJ/m², enhancing bond strength and compliance with EN 13501-6:2018 classification A1, using materials like aluminum sheets and specific primers such as BETASEAL and DOWSIL products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesive systems are used in composite metallic panels, then general bonding functionality is achieved, but bond strength is insufficient and delamination occurs during service
Solution Approach 1:
A silicone-based primer coating is introduced as an intermediary layer between the metallic sheet and the adhesive. The primer contains silane or siloxane compounds that chemically bond to both the metal substrate and the adhesive, creating a strong interfacial connection that prevents delamination while maintaining bonding functionality.
Solution Approach 2:
The adhesive system is formulated as a composite comprising organosilicon polymers combined with reactive silane or siloxane modifiers. This composite adhesive structure provides both the bonding characteristics of conventional adhesives and the enhanced adhesion properties of silicone-based materials, resulting in superior bond strength and delamination resistance.
2Reliability
If standard adhesive materials are used in cladding panels, then structural bonding is achieved, but fire safety requirements (EN 13501-6:2018 classification A1) are not met
Solution Approach 1:
The adhesive formulation is modified by incorporating organosilicon materials with specific fire-retardant properties and controlling the gross heat of combustion to no greater than 1.4 MJ/m². This parameter change enables the adhesive to meet EN 13501-6:2018 classification A1 fire safety requirements while maintaining adequate bond strength through the silicone-based primer system.
3Strength
If adhesive systems with high bond strength are used, then bonding between sheets is improved, but fire safety performance deteriorates due to higher heat of combustion
Solution Approach 1:
The adhesive system utilizes organosilicon materials that inherently provide both strong bonding capability and fire retardation. The silicone-based primer and organosilicon adhesive combination converts the potential harm of high heat of combustion into a benefit by providing thermal stability and fire resistance, achieving bond strength while limiting gross heat of combustion to no greater than 1.4 MJ/m².
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 composite panel achieves improved bond strength and compliance with fire safety standards, demonstrated through enhanced peel strength and reduced risk of delamination, as shown by 180° and 90° peel adhesion tests, with suitable primers significantly improving adhesion between the adhesive and metallic sheets.
Implementation Method 1
a silicone-based primer coating on the inner surface of the first and second metallic sheets and an organosilicon adhesive contacting the primer coating
Data Source
Figure 1~3
AI summary
A composite panel comprises first and second metallic sheets each having an inner and outer surface, a silicone-based primer coating on the inner surface of the first and second metallic sheets and an organosilicon adhesive contacting the primer coating on both the first and second metallic sheets, wherein the adhesive has a gross heat of combustion (Q-PCS) of no greater than 1.4 MJ/m2. The panel is compliant with specification EN 13501-6:2018, classification A1.