Two-Component Coating Composition for Rapid Drying and Crack Bridging
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Solution Overview
Problem
Existing quick-drying coating compositions face challenges in crack-bridging properties, shrinkage, and drying times, especially under high humidity and low temperatures, with limitations in flexibility and freeze/thaw stability, and potential toxicity and skin-sensitization issues.
Innovation Solution
A process for producing an aqueous coating composition involving a pasty first component with fast-hardening hydraulic binders, retarders, curing accelerators, and organic polymeric binders, combined with an activator in the form of an alkali metal hydroxide, which improves crack-bridging and drying performance without significant mixing effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If rapid cements and calcium sulfate binders are used to accelerate drying, then drying speed is improved, but crack-bridging properties and flexibility deteriorate
Solution Approach 1:
The coating composition is divided into two separate components: Component A containing the rapid-setting binder (calcium aluminate cement or calcium sulfoaluminate cement) and Component B containing the polymer emulsion and flexible binder. This segmentation allows each component to perform its specialized function - rapid setting and flexibility respectively - without compromising the other, resolving the contradiction between fast drying and crack-bridging properties.
Solution Approach 2:
The invention creates a composite sealing system combining inorganic rapid-setting binders (calcium aluminate cement or calcium sulfoaluminate cement) with organic polymer emulsions (acrylic, vinyl acetate, or styrene-butadiene). This composite material integrates the fast-drying capability of mineral binders with the flexibility and crack-bridging properties of polymers, simultaneously achieving both improved drying speed and maintained structural integrity.
2Strength
If polymer content is increased to improve crack-bridging properties, then flexibility is improved, but drying time increases
Solution Approach 1:
The formulation separates polymer-based flexible binders into Component B, distinct from the rapid-setting inorganic binder in Component A. This segmentation enables the polymer to provide crack-bridging properties without interfering with the fast drying mechanism of the inorganic binder, allowing both high flexibility and rapid drying to coexist.
Solution Approach 2:
The invention specifies precise polymer content ranges (5-30% by weight of total composition) and uses polymers with specific glass transition temperatures (Tg between -50°C and 0°C) to optimize the balance between flexibility and drying speed. By controlling these parameters, the system achieves adequate crack-bridging properties while maintaining rapid drying characteristics.
3Productivity
If lithium hydroxide and lithium sulfate are used as accelerators, then curing speed is improved, but mixing effort and complexity increase
Solution Approach 1:
The accelerating agents (lithium hydroxide and lithium sulfate) are incorporated into Component A along with the rapid-setting binder, creating a pre-formulated accelerated cement mixture. This segmentation concentrates all acceleration functions in one component, simplifying the mixing process compared to adding multiple separate accelerators, while maintaining fast curing performance.
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 enhances mechanical properties, reduces cracking and shrinkage, and ensures rapid drying and adhesion, even in adverse conditions, while being safer and easier to produce, making it suitable for various sealing applications.
Implementation Method 1
at least one fast-hardening hydraulic binder selected from calcium aluminate cement, calcium sulfoaluminate cement or a mixture thereof
Implementation Method 2
adding a second component (b) which comprises at least one activator, the activator being an alkali metal hydroxide
Implementation Method 3
adding at least one organic polymeric binder to the mixture of (a1) to (a3)
Data Source
AI summary
The invention relates to a method for producing an aqueous coating mass based on a quick-hardening hydraulic binder, which is applied as a fluid onto a substrate, and the corresponding coating compound. The aqueous paste-like first component of the coating mass contains, in addition to calcium (sulfo)aluminate cement, an organic polymer binder, a retarder, and lithium sulfate and/or lithium acetate as a hardening accelerator. After prior activation by addition of the second component, containing at least one activator, the coating masses yield coatings with improved complete-drying properties.