Coating Composition pH Stabilization via Alkaline Buffer System
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Solution Overview
Problem
Conventional storage-stable coating compositions for buildings face challenges in maintaining a high pH level over time to prevent microbial infestation, as existing preservatives are subject to legal restrictions and pH-increasing methods like adding lye are not sustainable, requiring a more effective and legally compliant solution.
Innovation Solution
A combination of alkaline earth metal hydroxides and alkali metal carbonates is used to maintain a pH of at least 10 for extended periods, enhancing the buffering effect of water glass or siliconate systems by adding calcium hydroxide and lithium carbonate, which slowly release hydroxide ions to stabilize the pH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional preservatives are used to prevent microbial infestation, then the composition is protected against microbes, but they are subject to legal restrictions and may not be usable
Solution Approach 1:
The patent removes conventional preservatives from the composition and replaces them with an alkaline buffer system (pH 10-13) that prevents microbial infestation through high pH rather than chemical preservatives. This extraction of problematic substances resolves the contradiction between effective protection and legal compliance.
Solution Approach 2:
The patent changes the pH parameter of the composition to a highly alkaline range (pH 10-13) to create an environment that is inherently hostile to microorganisms. This parameter change eliminates the need for conventional preservatives while maintaining protection, thus resolving the legal compliance issue.
2Reliability
If lye (NaOH or KOH) is added to increase pH and prevent microbial infestation, then the pH value increases initially, but it drops again within a few days or weeks, weakening the protection
Solution Approach 1:
The patent incorporates alkaline earth metal hydroxides and alkali metal carbonates into the composition in advance, creating a buffer system that proactively maintains pH stability. This preliminary buffering action prevents pH drop before it can occur, resolving the contradiction between initial pH increase and long-term pH maintenance.
Solution Approach 2:
The buffer system created by alkaline earth metal hydroxides and alkali metal carbonates provides a feedback mechanism that automatically resists pH changes. When pH tends to drop, the buffer components react to release hydroxide ions and maintain the alkaline pH, ensuring sustained microbial protection without active monitoring or adjustment.
3Reliability
If water glass or siliconate is used as a buffer system, then the buffer capacity is large in the highly alkaline range, but additional base sources are needed to ensure sufficient pH maintenance over time
Solution Approach 1:
The patent merges water glass or siliconate buffer system with alkaline earth metal hydroxides and alkali metal carbonates to create a synergistic buffer system. This combination consolidates buffering capacity and base supply into a single integrated system, reducing the need for excessive quantities of individual components while ensuring sustained pH maintenance.
Solution Approach 2:
The patent creates a composite buffer system combining multiple chemical components (water glass/siliconate + alkaline earth metal hydroxide + alkali metal carbonate) that work together to provide enhanced buffering capacity and sustained base supply. This composite approach optimizes the performance of each component while reducing the total quantity needed compared to using single substances.
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
This combination ensures a stable pH of at least 10 for 30 days to 720 days, effectively preventing microbial infestation while being cost-effective and compliant with legal regulations, ensuring the composition's usability and safety.
Implementation Method 1
a buffer system based on water glass or based on siliconate and, if necessary, conventional preservatives. The contents are such that they are sufficient to adjust and maintain a pH of at least 10 of the composition for at least 30 days
Implementation Method 2
The invention combines the buffering effect of the known water glass or siliconate-based systems with a source of hydroxide ions, and thus achieves increased security that the pH value of the composition is sufficiently high and remains sufficiently high even over long periods of time
Implementation Method 3
Due to its -O-Si(OH) x groups, x = 1 - 3, water glass is a suitable buffer with a large buffer capacity in the highly alkaline range. The same applies to the siliconate system.
Data Source
AI summary
The invention relates to a storage-stable composition for forming coatings on buildings and the like, comprising at least one organic binder, at least one filler and/or pigment, water to adjust the composition to a pasty consistency, a buffer system based on water glass or siliconate, and optionally conventional additives, as well as a content of 0.01 wt.% to 30 wt.% of at least one alkaline earth hydroxide and 0.01 wt.% to 10 wt.% of at least one alkali carbonate, each based on the total weight of the composition.