pH-Responsive Catechol Copolymers for Low-Dose Rheological Control
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Solution Overview
Problem
Current rheological additives, such as HASE and ASE polymers, require high concentrations to achieve desired thickening properties in aqueous systems like paints and coatings, which can lead to inefficiencies and increased material usage.
Innovation Solution
Development of pH-responsive copolymers composed of specific unsaturated monomers, which are insoluble at low pH but swell and thicken at higher pH, allowing for reduced additive levels while maintaining effective rheological profiles in aqueous coatings and latex binders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high concentrations of HASE and ASE polymers are used to achieve desired thickening properties, then the rheological performance is improved, but the material usage and formulation efficiency deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of polymer monomers to achieve enhanced thickening efficiency. Specifically, it uses comonomers with polyether groups (R2 and R6) and ethylenic unsaturation (R4 and R8) that create stronger hydrophobic interactions and more effective three-dimensional networks at lower concentrations, thereby improving rheological performance while reducing material usage.
Solution Approach 2:
The patent employs composite materials by combining multiple monomer types in copolymerization: (a) ethylenically unsaturated carboxylic acid, (b) nonionic ethylenically unsaturated monomer with polyether groups, and (c) ethylenically unsaturated hydrophobic monomer. This composite approach creates polymers with synergistic properties that enhance thickening efficiency beyond what single monomer systems can achieve.
2Ease of operation
If high concentrations of rheological additives are used to achieve desired thickening properties, then the viscosity control is improved, but the formulation efficiency and application uniformity deteriorate
Solution Approach 1:
The patent changes the chemical parameters of the polymer system by introducing monomers with specific functional groups (polyether groups R2/R6 and hydrophobic groups R4/R8) that enhance intermolecular interactions. This results in more effective thickening at lower concentrations, improving both viscosity control and formulation efficiency simultaneously.
3Reliability
If conventional HASE and ASE polymers are used, then the thickening effect is achieved, but the water sensitivity and application properties deteriorate
Solution Approach 1:
The patent uses composite monomer systems combining carboxylic acid groups (for pH-responsive thickening), polyether groups (for hydrophobic aggregation), and additional hydrophobic groups (for enhanced network formation). This composite structure creates more effective three-dimensional networks that provide superior thickening effect while reducing adverse water sensitivity through stronger hydrophobic interactions.
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 pH-responsive copolymers achieve improved thickening efficiency with lower concentrations, enhancing water sensitivity and reducing material usage in aqueous coating formulations, resulting in improved application properties and uniformity.
Implementation Method 1
Under the influence of a base, organic or inorganic, the HASE particles gradually swell and expand to form a three-dimensional network by intermolecular hydrophobic aggregation between HASE copolymer chains
Implementation Method 2
These polymers are substantially insoluble in water at a low pH. However, at higher pH they become swellable or soluble in water and thus exhibit thickening behavior
Implementation Method 3
These alkali-swellable and alkali-soluble polymers are carboxyl functional polymers synthesized by free radical polymerization
Data Source
AI summary
Disclosed are novel substituted catechol monomers, polymers made with the substituted catechol monomers, pH responsive polymers made with the substituted catechol monomers, and related methods. Also provided is a method of preparing an aqueous coating composition such as a latex paint including the above components.