Aqueous Coating Dispersion with Polysiloxane for Corrosion Resistance
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Solution Overview
Problem
Existing aqueous coating compositions lack sufficient anti-corrosion, water resistance, and water repellency properties to meet industry requirements for applications such as general industrial finishes and agriculture construction equipment coatings.
Innovation Solution
A stable aqueous dispersion of polymeric particles is developed by incorporating hydroxyl-terminated polysiloxane into the polymerization process of a specific emulsion polymer, which includes structural units of ethylenically unsaturated phosphorous acid monomers and functional monomers, resulting in improved corrosion resistance, water resistance, and water repellency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If aqueous coating compositions are used instead of solvent-borne coating compositions, then environmental problems are reduced, but anti-corrosion performance and water resistance are insufficient
Solution Approach 1:
The invention uses a composite polymer system combining acrylic emulsion polymer with hydroxyl-terminated polysiloxane and phosphorous acid monomer units. This composite structure integrates the environmental benefits of aqueous systems with the protective properties of siloxane and phosphorous compounds, achieving both reduced environmental impact and enhanced anti-corrosion performance through synergistic material combination
Solution Approach 2:
The invention modifies the chemical composition parameters of the aqueous coating by incorporating specific functional monomers (phosphorous acid monomers at 0.5-1.8% and functional monomers with amide, carboxyl, sulfonic acid, or sulfate groups at 0-5.0%). These parameter changes transform the aqueous system from inadequate protective performance to meeting industry standards for anti-corrosion and water resistance
2Object-affected harmful factors
If aqueous coating compositions are used instead of solvent-borne coating compositions, then environmental problems are reduced, but water resistance and water repellency are insufficient
Solution Approach 1:
The composite polymer system integrates hydroxyl-terminated polysiloxane with acrylic emulsion polymer containing phosphorous acid monomer units. The siloxane component provides hydrophobicity and water repellency, while the phosphorous acid units contribute to corrosion resistance, creating a composite material that simultaneously achieves water resistance and reduced environmental impact
Solution Approach 2:
The invention introduces specific functional groups (hydroxyl groups from polysiloxane, phosphorous acid groups, and other polar groups from functional monomers) at specific locations within the polymer structure. These localized functional groups provide targeted water resistance and repellency properties without compromising the overall aqueous nature of the coating composition
3Reliability
If hydroxyl-terminated polysiloxane is incorporated into emulsion polymerization, then corrosion resistance and water resistance are improved, but manufacturing complexity increases
Solution Approach 1:
The invention merges the hydroxyl-terminated polysiloxane incorporation step with the existing emulsion polymerization process. By combining these operations into a single integrated manufacturing step, the system achieves improved corrosion resistance without proportionally increasing manufacturing complexity, as the polysiloxane is incorporated during the same reaction conditions used to form the emulsion polymer
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 aqueous coating composition derived from this dispersion exhibits enhanced corrosion resistance, water resistance, and water repellency, meeting or exceeding industry standards for coatings, including a blister rating of 6M or better and a rust rating of 7P or better after 240 hours of salt-spray testing.
Implementation Method 1
polymerization of monomers in an aqueous medium in the presence of a hydroxyl-terminated polysiloxane to obtain the aqueous dispersion of polymeric particles
Implementation Method 2
the emulsion polymer comprises, by weight based on the weight of the emulsion polymer, more than 0.5% to 1.8% of structural units of an ethylenically unsaturated phosphorous acid monomer, a salt thereof, or mixtures thereof; and from zero to 5.0% of structural units of an ethylenically unsaturated functional monomer
Data Source
AI summary
An aqueous dispersion of polymeric particles comprising a specific emulsion polymer and a hydroxyl-terminated polysiloxane, and an aqueous coating composition comprising the aqueous dispersion providing coatings made therefrom with improved water resistance, anti-corrosion, and water repellency properties.