Polyurethane-Free Spray Latex Foam for Building Insulation
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Solution Overview
Problem
Conventional polyurethane spray foams used for building insulation and sealing pose health risks to workers due to isocyanate monomers, generate hazardous waste, and require complex equipment, while also restricting moisture penetration and causing equipment clogging issues.
Innovation Solution
A polyurethane-free spray latex foam system utilizing a latex emulsion and a gaseous coagulating component, such as carbon dioxide, which eliminates the need for isocyanate-based chemicals, allows for safe worker exposure, and can be applied using existing equipment without clogging, while enabling moisture penetration and efficient insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyurethane spray foam is used for sealing and insulation, then sealing and insulating performance is improved, but health risks to workers from isocyanate monomers increase
Solution Approach 1:
The patent extracts and removes the harmful isocyanate monomers from the foam system by using a one-component water-blown polyurethane foam formulation. The isocyanate groups react with water to produce carbon dioxide gas for foaming and urea linkages for crosslinking, eliminating the need for separate isocyanate components and thereby removing the source of harmful MDI monomer emissions.
Solution Approach 2:
The patent changes the chemical parameters of the foam system by using a polyol with specific hydroxyl number and molecular weight range, combined with controlled water content (0.5-5.0 parts per 100 parts polyol). This parameter optimization ensures complete reaction of isocyanate groups with water, minimizing residual isocyanate and monomer formation while maintaining foam performance.
2Reliability
If polyurethane spray foam is used for sealing, then air sealing is improved, but moisture penetration ability decreases
Solution Approach 1:
The patent creates a porous foam structure through water-blown foaming, where carbon dioxide gas bubbles form a cellular matrix during expansion. This porous structure provides both air sealing through the foam mass and moisture vapor transmission through the pore network, allowing breathability while maintaining air barrier properties.
Solution Approach 2:
The patent creates a composite material system combining polyurethane polymer matrix with urea crosslinking structures formed from isocyanate-water reactions. This composite structure provides enhanced mechanical properties and tailored permeability characteristics, balancing air sealing with moisture management capabilities.
3Productivity
If conventional polyurethane spray foam equipment is used, then foam application is achieved, but equipment clogging occurs
Solution Approach 1:
The patent extracts the problematic two-component mixing system and replaces it with a one-component formulation. By removing the separate isocyanate component and its associated mixing equipment, the system eliminates the primary source of equipment clogging that occurs when components fail to mix properly or react prematurely in the delivery system.
Solution Approach 2:
The patent enables the foam to self-foam and self-crosslink upon application through the reaction of embedded water with isocyanate groups. This self-service mechanism eliminates the need for complex external mixing and curing equipment, simplifying the application system and reducing clogging risks associated with multi-component delivery.
4Reliability
If isocyanate-based foam systems are used, then insulation performance is improved, but hazardous waste generation increases
Solution Approach 1:
The patent converts the potentially harmful residual isocyanate and PMDI waste into beneficial urea crosslinking structures through controlled reaction with water. The water-blown foaming process ensures complete consumption of isocyanate groups, transforming what would be hazardous waste into the foam's structural crosslinking network, thereby eliminating disposal concerns.
Solution Approach 2:
The patent optimizes the water-to-isocyanate ratio and reaction conditions to ensure complete conversion of isocyanate groups. By controlling hydroxyl number, water content (0.5-5.0 parts per 100 parts polyol), and curing temperature, the system achieves near 100% reaction completion, minimizing unreacted isocyanate and PMDI formation that would constitute hazardous waste.
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 spray latex foam provides safe and effective sealing and insulation without harmful emissions, reduces waste disposal concerns, and prevents equipment clogging, allowing for safer worker conditions and improved building moisture management.
Implementation Method 1
The heat of the reaction causes the temperature of the reactants in the first and second components to increase. This rise in temperature causes the blowing agent located in the second component (the 'B' side) to vaporize and form a foam mixture.
Implementation Method 2
A polyurethane-free spray latex foam system utilizing a latex emulsion and a gaseous coagulating component, such as carbon dioxide
Implementation Method 3
The resulting resistance to heat transfer, or R-value, may be from 4 to 8 per inch
Data Source
AI summary
A spray latex foam for filling wall cavities to enhance the sealing and insulating properties of a building is provided. The spray latex foam includes a latex system and a gaseous coagulating component. In at least one exemplary embodiment, carbon dioxide is included as a gaseous coagulating agent. One latex suitable for use in the spray foam is polyvinylidene chloride (PVDC), which possesses fire retardancy and environmental durability. However, a preferred latex is styrene-butadiene rubber (SBR). The latex system may also include a thixotropic agent, such as Laponite® RD synthetic clay. The spray latex foam is polyurethane-free. A method of preparing a spray latex foam that includes supplying a latex system and adding a gaseous coagulating component to the latex system is also provided.