Gas-Impermeable Insulating Panel Structure for Building Roofs
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Solution Overview
Problem
Existing gas-impermeable insulating panels for buildings face issues such as micro-hole formation due to contact with fibreglass, low dimensional stability, inability to be hot-scarfed, poor resistance to abrasion and water, incompatibility with adhesives, and compromised fire-resistance and thermal insulation due to gas diffusion.
Innovation Solution
A panel structure comprising a hot-scarfable layer of polypropylene non-woven fabric or polyethylene film, an elastoplastomeric bituminous mixture, and multiple layers of polyethylene or polypropylene films with a PIR/PUR core, allowing for gas impermeability and hot-scarfing capability while enabling adhesive application and improved resistance to abrasion and water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin aluminium foil covering is used to prevent gas diffusion, then gas impermeability is improved, but micro-holes are created due to direct contact with fibreglass, impairing insulating properties
Solution Approach 1:
A smooth protective layer is introduced between the fibreglass and the aluminium foil covering. This intermediary layer prevents direct contact between the sharp fibreglass and the thin foil, eliminating micro-hole formation while maintaining gas impermeability. The protective layer acts as a mediator that preserves the integrity of the gas-tight barrier.
Solution Approach 2:
The panel structure uses a composite construction with multiple layers including fibreglass for dimensional stability, a smooth protective layer, and aluminium foil for gas impermeability. This composite approach allows each layer to perform its specific function without compromising the others, resolving the contradiction between gas tightness and protection from mechanical damage.
2Reliability
If aluminium foil or plastic film covering is used to ensure gas impermeability, then gas diffusion is prevented, but the panel cannot be hot-scarfed, limiting roof application
Solution Approach 1:
The panel structure is segmented into distinct functional layers: an outer layer designed for hot-scarfing attachment to the roof, and an inner gas-tight barrier layer. This segmentation allows the panel to achieve both hot-scarfing capability and gas impermeability, as each layer performs its specific function without interfering with the other.
Solution Approach 2:
The solution addresses the contradiction by adding a dimensional layering approach rather than trying to make a single material perform both functions. The hot-scarfable outer layer and the gas-tight inner layer operate in different functional dimensions, allowing the panel to be both hot-scarfable and gas-impermeable simultaneously.
3Reliability
If smooth aluminium foil or plastic film is used for gas impermeability, then gas diffusion is blocked, but resistance to abrasion and water is poor, reducing durability
Solution Approach 1:
The panel uses a segmented multi-layer structure where the gas-tight barrier layer is separated from the outer surface layer. The outer layer provides abrasion and water resistance, while the inner layer maintains gas impermeability. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The panel employs composite materials with distinct properties: an outer layer with high abrasion and water resistance, and an inner layer with gas impermeability. This composite construction resolves the contradiction by combining materials that excel at different functions, allowing the panel to be both durable and gas-tight.
4Loss of substance
If thinner panels are used to reduce material quantity, then CO2 emissions are reduced, but gas diffusion increases, impairing thermal insulation
Solution Approach 1:
The invention extracts the gas-tightness function from the bulk polymer matrix and implements it through a dedicated barrier layer. This allows thinner panel construction with reduced polymer quantity while maintaining effective gas diffusion prevention through the specialized barrier layer, thus preserving thermal insulation performance.
Solution Approach 2:
The invention changes the parameter of gas diffusion resistance by introducing a low-permeability barrier layer rather than relying solely on polymer thickness. This parameter change allows thinner panels to achieve the same gas diffusion prevention and thermal insulation performance as thicker panels without the barrier layer.
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 panel structure maintains gas impermeability over time, allows for hot-scarfing, and provides enhanced resistance to abrasion, water, and fire, while ensuring thinner panels with improved thermal insulation and reduced CO2 emissions.
Implementation Method 1
a gas-impermeable covering (i.e. impermeable to gas)
Implementation Method 2
Insulating materials with cellular structures have a reduced average thermal conductivity λ
Implementation Method 3
the small size of the closed cells limits the thermal convection between the gas and the internal surface of such cells
Data Source
Figure 1
AI summary
A panel structure that is impermeable to gases, particularly for the insulation of buildings, constituted by a hot-scarfable layer that is composed of a first layer composed of polypropylene non-woven fabric or polyethylene film or PP film (optionally treated with silicone) or talc or sand and of a second layer that is composed of a first elastoplastomeric bituminous mixture with adhesive properties, and of a third layer that is constituted by LDPE or LLDPE or HDPE or PP or PA or EAA or EVA or EVOH or PET (10-40) µ which is made by means of extrusion, and of a fourth layer that is constituted by paper with a grammage comprised between (40-100)g/m2 with rough or crown effect, and of a fifth layer that is constituted by PE or PP or PET (10-40) µ which is made by means of extrusion and which functions as an adhesive layer, of a sixth layer that is constituted by aluminium (7-30 µ), and of a seventh layer that is constituted by PE or PP or PET (10-40) µ and is made by means of extrusion or which is constituted by lacquering (for example epoxy, acrylic, nitro), and of an eighth layer that is constituted by a PIR/PUR panel.