Sag-Resistant Vapor Permeable Barrier Coating for Low Temperature Application
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Solution Overview
Problem
Existing liquid barrier coating compositions for construction surfaces at sub-freezing temperatures face issues with ion intolerance, reduced elongation, and hindered film formation due to the use of metal salts like calcium nitrate, which are difficult to incorporate in emulsions and combine with ethanol evaporation-enhancing agents.
Innovation Solution
A two-component system comprising a first component with a water-based, flame-retardant, acrylic emulsion and a second component with a freezing point depressing agent and associative thickener, mixed at the job site to create a liquid coating that can be applied at low temperatures, avoiding the use of alkali or alkaline earth metal salts and enhancing film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal salts like calcium nitrate are used as freezing point depressing agents, then the coating can be applied at sub-freezing temperatures, but the emulsion becomes ion intolerant and coagulates due to high ion concentrations
Solution Approach 1:
The patent removes metal salts from the formulation entirely, extracting the harmful ionic component while retaining the freezing point depression function through alternative means. The emulsion is made ion-intolerant-free by eliminating calcium nitrate and other metal salts that cause coagulation.
Solution Approach 2:
The patent changes the chemical parameters of the formulation by replacing ionic freezing point depressants with non-ionic alternatives. This involves modifying the composition to use compounds that do not dissociate into ions, thereby preventing emulsion coagulation while still enabling sub-freezing application.
2Temperature
If metal salts are used as freezing point depressing agents, then low temperature application is enabled, but the dried coating elongation is reduced which is necessary for bridging cracks
Solution Approach 1:
The patent extracts metal salts from the formulation, removing the source of ionic interference that reduces polymer chain flexibility. By eliminating calcium nitrate, the coating maintains its ability to elongate and bridge cracks while still achieving low-temperature application capability through non-ionic alternatives.
3Loss of time
If metal salts are combined with ethanol evaporation-enhancing agent, then drying time is reduced, but film formation is hindered
Solution Approach 1:
The patent converts the potential harm of using ethanol alone (which may not provide sufficient freezing point depression) into a benefit by combining it with non-ionic compounds. This combination maintains the rapid evaporation and drying time enhancement while avoiding the film formation issues caused by metal salt-ethanol interactions.
Solution Approach 2:
The patent changes the chemical composition parameters by replacing ionic freezing point depressants with non-ionic alternatives. This modification allows ethanol to function effectively as an evaporation-enhancing agent without the detrimental interactions that occur when combined with metal salts, thereby preserving film formation quality.
4Temperature
If two-component system is used with mixing at job site, then proper formulation for low temperature application is achieved, but the system complexity increases
Solution Approach 1:
The patent segments the formulation into two separate components: Component A containing the acrylic emulsion and Component B containing the freezing point depressant and thickener. This segmentation allows each component to be optimized independently and mixed in correct proportions at application, ensuring proper formulation while managing complexity through systematic separation.
Solution Approach 2:
The patent performs preliminary preparation by pre-formulating Component A and Component B with all necessary ingredients in correct ratios. This preliminary action ensures that when the components are mixed at the job site, the resulting formulation immediately has the correct composition for low-temperature application, eliminating the need for complex on-site adjustments.
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 system allows for effective application and drying of a flame-retardant, water-vapor permeable air barrier membrane at sub-freezing temperatures, improving film formation and elongation properties compared to prior art, while maintaining sag resistance and preventing coating sagging.
Implementation Method 1
an emulsion of an acrylic polymer or copolymer which forms a flexible film
Implementation Method 2
an emulsion of an acrylic polymer or copolymer which forms a flexible film
Implementation Method 3
a second component having a freezing point depressing agent
Implementation Method 4
a second component having a freezing point depressing agent and certain thickener
Implementation Method 5
applying onto a construction surface a coating of the water-based liquid composition obtained from mixing together said first and second components, and allowing said applied coating to dry
Data Source
AI summary
Methods and systems of the invention, for achieving a liquid-applicable, aqueous-based coating composition that forms a water-impermeable, vapor permeable barrier coating when applied onto a construction surface and allowed to dry, involve mixing together separate first and second components, wherein the first component comprises an acrylic emulsion, flame retardant, clay, and optionally at least one additive selected from thickeners (e.g., cellulosic), fillers, and other conventional additives; and wherein the second component comprises a freezing point depressing agent with a specific type of thickener selected from the group of associative thickeners, alkali soluble emulsion thickeners, or mixture thereof, to obtain the liquid-applicable coating. The present invention achieves low temperature film formation without reliance upon calcium nitrite, calcium nitrate, or sodium chloride type of freezing point depressing salts. The coating can be applied at low (e.g., sub-freezing) temperatures onto a construction surface such as wood, fiberboard, gypsum, cement, concrete, and other building substrates to achieve an effective barrier membrane.