Segmented Adhesive Membrane for Lateral Airtightness
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Solution Overview
Problem
Existing adhesive barrier membranes against air and humidity permeable to water vapor for building surfaces are either expensive to produce or do not provide perfect airtightness laterally.
Innovation Solution
A membrane comprising a water vapor permeable film with a first layer of pressure-sensitive adhesive deposited on its entire lower face to a thickness less than 50 µm and a second layer covering 2 to 99% of the surface with a thickness between 50 µm and 2 mm, using hot melt glue, which includes a microporous or oriented polymer film, and a protective film covering the second adhesive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a discontinuous adhesive film is applied to provide good airtightness laterally, then lateral airtightness is improved, but production cost increases
Solution Approach 1:
The adhesive layer is segmented into two distinct layers: a first layer with thickness less than or equal to 50 μm providing base adhesion, and a second layer with thickness between 50 μm and 2 mm providing enhanced lateral airtightness. This segmentation allows each layer to perform its specific function optimally while controlling overall material usage and production cost.
Solution Approach 2:
The second adhesive layer is applied selectively to cover only 2 to 99% of the surface of the first layer, rather than uniformly covering the entire membrane. This local quality approach concentrates the thicker, more cost-intensive adhesive material precisely where lateral airtightness is critical (at joints and overlaps), while maintaining cost-effectiveness in other areas.
2Strength
If adhesive layer thickness is increased to improve adhesion, then adhesion strength is improved, but water vapor permeability decreases
Solution Approach 1:
The adhesive system is divided into two layers with different thicknesses and functions. The first layer (≤50 μm) maintains water vapor permeability while providing base adhesion, and the second layer (50 μm to 2 mm) provides enhanced adhesion strength where needed. This segmentation resolves the contradiction by spatially separating the two competing requirements.
Solution Approach 2:
The thicker second adhesive layer is applied only to specific portions (2 to 99% coverage) of the membrane surface, specifically where enhanced adhesion is needed for lateral airtightness. This localized application ensures high adhesion strength at critical joints while preserving water vapor permeability in other areas through the thinner first 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 solution provides a cost-effective, adhesive membrane with improved lateral airtightness and minimal reduction in water vapor permeability, outperforming prior art in breathability while maintaining effective adhesion to building surfaces.
Implementation Method 1
the microporous structure of the membranes allowing the passage of water vapor while preventing the passage of air. Indeed, the molecular structure of water vapor allows it to pass through pores smaller than oxygen and nitrogen in particular.
Implementation Method 2
Said membranes are fixed to the walls of the building by means of the adhesive layer, usually a pressure sensitive adhesive
Data Source
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Figure 3
AI summary
The present invention relates to an air and moisture barrier adhesive membrane permeable to water vapor, intended for building surfaces, comprising at least one water vapor permeable film (1) and a layer of pressure-sensitive adhesive, said adhesive layer being deposited on one of the faces, said lower face, of the film; said membrane is remarkable in that it comprises a first layer (2) of a pressure-sensitive adhesive deposited on the entire lower face of the film with a thickness less than or equal to 50 µm and a second layer (3) of a pressure-sensitive adhesive deposited on said first layer (2) to cover the first layer (2) over 2 to 99% of the surface of the first layer (2) with a thickness between 50 µm and 2 mm.