Aqueous Coating Stain Resistance via Anionic Surfactant Composition
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Solution Overview
Problem
Aqueous coating compositions face challenges in achieving good staining resistance and penetration resistance, especially at high pigment to binder ratios, while maintaining uniform film formation and mechanical strength, which is often compromised by the use of volatile coalescents that harm the environment.
Innovation Solution
Incorporating at least 85% by weight of specific anionic surfactants, such as semi-esters of sulfuric or phosphoric acid with alkyl radicals or alkylphenyl radicals, into the coating composition to enhance stain resistance and penetration resistance without adversely affecting wash, scrub, or burnish resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If volatile coalescents are used to lower minimum film-forming temperature, then film formation is improved, but environmental sustainability deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the binder formulation by incorporating specific anionic surfactants (sulfonated or sulfated fatty acid esters) to modify film formation behavior. This allows achieving good film formation at lower coalescent concentrations through parameter optimization rather than relying on volatile compounds
Solution Approach 2:
The invention replaces expensive and environmentally harmful volatile coalescents with cheaper, non-volatile anionic surfactants that provide the necessary film formation assistance without the environmental burden of evaporation into the atmosphere
2Reliability
If pigments are added to coating compositions, then coating performance is improved, but stain penetration resistance deteriorates
Solution Approach 1:
The anionic surfactants act as intermediary substances between the pigments and the coating matrix, modifying the interfacial properties to prevent aqueous stains from penetrating through the pigment particles into the substrate while maintaining the pigments' functional benefits
Solution Approach 2:
The invention changes the surface chemical parameters of the coating by introducing anionic surfactants with specific hydrophobic-hydrophilic balance, creating a surface property that repels aqueous stains even in the presence of high pigment concentrations
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 use of high concentrations of specific anionic surfactants significantly improves the coating's ability to resist stains and prevent their penetration, maintaining the coating's mechanical strength and environmental sustainability by reducing the need for volatile coalescents.
Implementation Method 1
incorporating at least 85% by weight of specific anionic surfactants, such as semi-esters of sulfuric or phosphoric acid with alkyl radicals or alkylphenyl radicals, into the coating composition to enhance stain resistance and penetration resistance
Data Source
AI summary
The invention also relates to a method to increase stain resistance and penetration resistance of aqueous coating compositions which method comprises providing a coating composition which contain at least one pigment, at least one film-forming polymer in the form of an aqueous polymer dispersion and at least one anionic surfactant, wherein the anionic surfactant comprises at least 85% by weight, preferably at least 90% by weight, more preferably at least 95% by weight, based on the total weight of anionic surfactant in the coating composition, of at least one anionic surfactant S, which is selected from semi-esters of sulfuric acid or phosphoric acid with an alcohol, which alcohol carries at least one alkyl radical having from 8 to 30 carbon atoms or an alkyl substituted phenyl radical wherein alkyl has from 4 to 30 carbon atoms and which alcohol may carry an oligo-C2-C3-alkylene-ether group provided that the number of repeating units in the oligo-C2-C3-alkylene-ether group is at most 15, or a salt thereof.