Aminosilane Waterborne Admixture Prevents Latex Flocculation
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Solution Overview
Problem
Aminosilanes used in latex paints hydrolyze and condense in water, leading to flocculation of anionically stabilized latex, which complicates paint formulation and can detract from other properties, especially in low VOC waterborne systems.
Innovation Solution
Aqueous coating composition comprising a neutralized or partially neutralized aminosilane and a hydrophobically modified alkylene oxide urethane polymer, with a specific weight-to-weight ratio and pH control, to prevent flocculation and enhance stain removal and film appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aminosilane is added to waterborne latex paint, then adhesion and stain blocking are improved, but flocculation of anionically stabilized latex occurs due to hydrolysis and condensation
Solution Approach 1:
A water-soluble polymeric thickening agent is introduced as an intermediary substance between the aminosilane and the anionically stabilized latex. This thickening agent mediates the interaction by providing steric stabilization that prevents flocculation while allowing the aminosilane to perform its adhesion-enhancing function. The polymer acts as a protective intermediary that interferes with the harmful aggregation process.
Solution Approach 2:
The patent changes the pH parameter of the system by using neutralized or partially neutralized aminosilane and controlling the overall formulation pH. This parameter change slows down the hydrolysis and condensation rate of the aminosilane, reducing the formation of polycationic species that cause flocculation, while still allowing the aminosilane to provide its beneficial effects.
2Stability of the object's composition
If aminosilane is diluted in organic solvent to prevent flocculation, then latex stability is improved, but VOC content increases making it impractical for low VOC systems
Solution Approach 1:
The water-soluble polymeric thickening agent serves as an intermediary that enables latex stabilization without requiring organic solvents. It provides a water-based mechanism for preventing flocculation, thus maintaining low VOC content while achieving the desired stability.
Solution Approach 2:
The patent changes the approach from solvent-based dilution to polymer-based stabilization. By adjusting the pH and introducing the polymeric thickening agent, the system achieves stability through a different mechanism that does not require organic solvents, thus maintaining low VOC content.
3Stability of the object's composition
If paint is carefully formulated to avoid aminosilane flocculation, then latex stability is maintained, but other paint properties are compromised
Solution Approach 1:
The polymeric thickening agent acts as a versatile intermediary that simultaneously addresses multiple requirements: it prevents flocculation, provides rheological control, and does not interfere with other paint properties. This single additive serves multiple functions, enhancing rather than compromising paint performance.
Solution Approach 2:
The water-soluble polymeric thickening agent is a multi-functional additive that performs multiple roles: it prevents aminosilane-induced flocculation, provides viscosity control, and maintains compatibility with various paint formulations. This universal additive does not compromise other paint properties and can be applied broadly across different systems.
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 composition effectively prevents flocculation, improves stain removal, and maintains film appearance in the final dried coating, while avoiding the use of organic solvents, thus providing a practical solution for low VOC latex paints.
Implementation Method 1
a hydrophobically modified alkylene oxide urethane polymer having a water soluble polymeric backbone with terminal or internal hydrophobic groups or both
Implementation Method 2
when exposed to water, aminosilanes hydrolyze and condense to form polymeric siloxane species
Implementation Method 3
aminosilanes hydrolyze and condense to form polymeric siloxane species
Data Source
AI summary
The present invention is a composition comprising an aqueous admixture of a neutralized or partially neutralized aminosilane and an associative thickener, wherein the admixture has a pH of less than 10.2. The admixture is beneficial as an easy-to-use paint additive that provides stain removal, stain blocking, and corrosion resistance for coatings from low VOC paints.