Self-Collapsing Polyurethane Foam Weather Barrier
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Solution Overview
Problem
Existing weather-resistive barriers and foamed-in-place gaskets in building construction are labor-intensive to apply, lack effective wind and water resistance, and often fail to adhere well to substrates, leading to uneven coverage and potential damage from subsequent construction steps.
Innovation Solution
The use of self-collapsing, one-component polyurethane foams with blowing agents and isocyanate prepolymers, combined with an aqueous polymeric coating, to create a flexible, easily compressible, and moisture-curable foam that forms a strong sealant, capable of bridging gaps and accommodating structural enclosures without compromising its sealant capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flexible sheeting material is used as weather-resistive barrier, then some protection against wind and liquid water is provided, but labor intensity increases and wind/water penetration occurs through overlaps and nail holes
Solution Approach 1:
The foam sealant applies itself to the substrate and automatically fills gaps and seams without requiring manual handling, unrolling, stretching, or fastening operations. The material self-adheres to wood, steel, or aluminum substrates and self-adjusts to accommodate surface irregularities, eliminating the need for complex installation procedures.
Solution Approach 2:
The foam undergoes phase change from liquid/gel application state to expanded solid foam, and subsequently to compressed solid foam after curing. This parameter change allows the material to transition from a easily applied liquid state to a dense, compacted state that provides superior weather resistance without requiring manual compression.
2Reliability
If liquid coatings with tapes are used to seal joints, then gaps between sheets can be bridged, but labor intensity increases due to separate coating application with trowel or scraper
Solution Approach 1:
The invention combines the sealing function and the coating function into a single foam sealant material. The foam simultaneously seals gaps between sheathing sheets and provides a continuous coating layer, eliminating the need for separate tape application and coating steps. The material is applied in a single operation and cures to provide both sealing and surface protection.
3Reliability
If expanded foams are used to seal joints, then gaps can be filled, but the foam does not compress when cladding is applied causing buckling or rippling
Solution Approach 1:
The foam sealant is designed with dynamic compressibility that allows it to deform under applied loads. When cladding is installed, the foam compresses to accommodate the mechanical pressure and surface irregularities, maintaining a uniform profile. The material's viscoelastic properties enable it to permanently deform under compression while maintaining sealing effectiveness.
4Reliability
If known one component polyurethane foams are used, then gaps can be filled and air/water passage blocked, but the foam expands or does not contract in use making it unsuitable for sleek foam profile applications
Solution Approach 1:
The foam composition is engineered to undergo reversible parameter changes in volume and density. During application, the foam expands to fill gaps and provide air/water blocking. After curing, the foam can be compressed to reduce volume and achieve a sleek profile, and this compression is maintained in service conditions.
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 quick-drying, strongly adherent, and easily compressible foam sealant that effectively forms a weather-resistant barrier, reducing labor costs and preventing damage from subsequent construction steps while maintaining a sleek profile and effective sealing.
Implementation Method 1
the one component polyurethane foam contains a) one or more blowing agents
Implementation Method 2
moisture curing one component polyurethane foams
Data Source
AI summary
The present invention provides a self-collapsing, moisture curable one component polyurethane foam (1K PU) composition from moisture curable polyurethane prepolymers and to methods of making weather resistant barriers and formed in place gaskets therefrom. The foam compositions are packed under pressure with a blowing agent. In the methods, the foams are applied to gaps in the exterior (sheathing) of a building under construction and collapse on cure to enable application an aqueous weather barrier coating thereover within an hour. The foams also cure when applied on or adjacent a structure to form a foam gasket that enables installation of additional structural elements over or adjacent the foam gasket without bowing or damage to the structure treated.