Aqueous Coating Material pH Stability via Alumino-Hydroxo Complex
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Solution Overview
Problem
Aqueous coating materials face challenges in maintaining high pH values over storage periods, leading to instability and potential microbial infestation, which complicates their use in allergy-friendly and preservative-free formulations.
Innovation Solution
The development of an aqueous coating material comprising a polymeric organic dispersion-based binder, an alumino-hydroxo complex, additives, and water, with a pH range of 8.5 to 12.5, utilizing alkali metal hydroxides and volatile neutralizing agents for pH adjustment, and inorganic carbonate or silicate fillers for stability, effectively maintaining alkaline conditions without the need for preservatives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preservatives are added to aqueous coating materials, then microbial contamination is prevented, but the coating becomes unsuitable for allergy sufferers and requires organic biocides
Solution Approach 1:
The invention changes the pH parameter of the aqueous coating material to a highly alkaline range (pH 11.0-13.0), which creates a biocidal environment without requiring organic preservatives. This parameter change fundamentally alters the chemical conditions to prevent microbial growth while remaining free of harmful biocides.
Solution Approach 2:
The invention converts the typically harmful effect of high pH (which can cause stability issues) into a beneficial biocidal effect. By maintaining pH in the 11.0-13.0 range, the coating system uses the alkalinity itself as the preservative mechanism, turning a potential problem into the solution for preventing microbial contamination.
2Reliability
If high pH values (8.5-12.0) are maintained to achieve biocidal effect, then microbial growth is inhibited, but storage stability and pH consistency deteriorate over time
Solution Approach 1:
The invention uses a composite pH adjustment system combining volatile neutralizing agents (ammonia, amines) with basic additives. This composite approach allows the system to maintain high pH while the volatile components provide buffering capacity to stabilize pH over storage time, preventing both microbial growth and pH drift.
Solution Approach 2:
The volatile neutralizing agents continuously evaporate and re-establish equilibrium, providing ongoing pH stabilization throughout storage. This continuous action ensures the pH remains consistently in the biocidal range without requiring additional preservatives or frequent adjustments.
3Temperature
If alkali metal hydroxides are used for pH adjustment, then high pH values are achieved, but excessive alkalinity (pH > 12) causes regulatory labeling requirements and handling issues
Solution Approach 1:
The invention optimizes the pH parameter to a specific range (11.0-13.0) that provides sufficient biocidal effect while avoiding the excessive alkalinity (>12) that triggers regulatory labeling requirements. This precise parameter control maintains effectiveness while improving safety and ease of handling.
Solution Approach 2:
The use of volatile neutralizing agents creates a dynamic pH system that can self-regulate. As the volatile components evaporate, they continuously re-establish the pH balance, allowing the system to maintain optimal alkalinity without requiring excessive initial pH adjustment, thereby improving handling safety.
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 solution provides stable alkaline aqueous coating materials with extended shelf life and reduced microbial growth, ensuring safety for allergy sufferers and avoiding the use of organic biocides, while maintaining excellent processing properties and weathering stability.
Implementation Method 1
The aqueous coating material according to the invention...consisting of or comprising a) at least one polymeric organic binder based on dispersion, b) at least one alumino-hydroxo complex, c) at least one additive, d) water...with a pH value in the range of 8.5 to 12.5
Implementation Method 2
utilizing alkali metal hydroxides and volatile neutralizing agents for pH adjustment
Implementation Method 3
inorganic carbonate or silicate fillers for stability, effectively maintaining alkaline conditions
Data Source
AI summary
The present invention relates to an aqueous coating material with a pH value in the range of 8.5 to 12.5, comprising a) a dispersion-based polymeric organic binder, b) an alumino-hydroxo complex, c) an additive, d) water, and e) optionally a filler. The invention further relates to the use of alumino-hydroxo complexes as pH buffers, particularly in the aqueous coating materials according to the invention. The invention also relates to a coating obtained from the coating material according to the invention and a substrate comprising a coatable surface and a coating according to the invention applied to this coatable surface.