Phosphorus-Containing Associative Thickener for Viscosity Drift Control
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Solution Overview
Problem
Aqueous polymer compositions containing phosphate- or phosphonate-containing monomers experience significant viscosity drift over time, making it challenging to maintain desired viscosity levels, which hinders commercialization and affects the performance of coatings and paints.
Innovation Solution
The use of an associative thickener with a polyoxyalkylene, polysaccharide, or polyvinyl alcohol backbone, featuring hydrophobic groups such as secondary amines, tertiary amines, or tertiary phosphines, which can be adjusted in pH to switch between hydrophilic and hydrophobic states, allowing for controlled viscosity modulation without the need for volatile organic solvents or costly additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional associative thickeners are used in aqueous polymer compositions containing phosphate- or phosphonate-containing monomers, then the desired viscosity is achieved initially, but significant viscosity drift occurs over time
Solution Approach 1:
The patent changes the chemical structure parameter of the thickener by incorporating phosphorus-containing groups (phosphate or phosphonate) into the polymeric backbone. This structural modification enables the thickener to interact compatibly with phosphorus-containing polymers, preventing the viscosity drift that occurs with conventional thickeners. The phosphorus-containing thickener maintains stable viscosity over time by forming compatible associations with the phosphorus-containing polymer units.
2Ease of operation
If the viscosity of aqueous thickener product is decreased for ease of use, then the product drains readily from storage container, but the active solids concentration is reduced
Solution Approach 1:
The patent modifies the chemical structure of the thickener by incorporating phosphorus-containing groups, which fundamentally changes the thickening mechanism. This structural change allows the thickener to achieve effective viscosity control at lower concentrations, thereby maintaining high active solids concentration while still providing the desired pourability and ease of incorporation into aqueous systems.
3Reliability
If phosphate- or phosphonate-containing polymers are used to improve titanium dioxide utilization and hiding, then coating performance is enhanced, but viscosity drift becomes significant
Solution Approach 1:
The patent introduces a phosphorus-containing thickener as an intermediary substance that mediates between the phosphorus-containing polymer and the aqueous medium. This intermediary thickener, containing phosphate or phosphonate groups in its backbone, is compatible with the phosphorus-containing polymer and prevents unwanted interactions that cause viscosity drift, while allowing the polymer to maintain its enhanced coating performance properties.
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
This approach results in aqueous compositions with minimal viscosity drift, enabling high solids content and improved thickening efficiency while maintaining environmental friendliness and cost-effectiveness, thereby stabilizing the viscosity of aqueous polymer systems.
Implementation Method 1
Associative thickeners are hydrophobically modified so as to provide an aqueous system with certain characteristics
Implementation Method 2
The pH of the aqueous composition is adjusted to above about 8, which is sufficient to cause deprotonation of the amine groups
Implementation Method 3
one or more of the hydrophobic groups comprises an acid suppressible amine functionality
Data Source
AI summary
Thickened aqueous compositions, and a method for controlling viscosity drift for thickened aqueous compositions comprising a pigment, a polymer containing polymerized units of phosphate- or phosphonate-containing monomers, and an acid suppressible thickener.