Nonionic Associative Thickener Viscosity Stability
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Solution Overview
Problem
Aqueous latex paints containing associative thickeners experience a decrease in viscosity with increasing temperature, leading to diminished application properties such as increased dripping and sagging, and settling of pigment or filler particles during storage or shipping.
Innovation Solution
A nonionic associative thickener comprising a vinyl addition polymer with at least two pendant polymeric chains, each with terminal chain segments selected from specific oxyethylene and oxypropylene units, providing improved temperature stability and viscosity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If associative thickeners are used to modify rheology of aqueous latex paints, then viscosity can be adjusted for application properties, but viscosity decreases with increasing temperature leading to increased dripping and sagging
Solution Approach 1:
The patent changes the chemical parameters of the thickener by incorporating temperature-responsive polymer segments that alter their conformation and hydrophobicity in response to temperature changes. This allows the thickener to maintain viscosity stability across a wide temperature range by dynamically adjusting its molecular interactions with the paint components.
Solution Approach 2:
The patent creates a composite thickener structure combining multiple polymer segments with different temperature responses. This composite architecture includes hydrophobic segments, hydrophilic segments, and temperature-responsive segments that work together to provide both thickening efficiency and temperature stability, resolving the contradiction between application properties and viscosity stability.
2Ease of operation
If associative thickeners are used to achieve desired viscosity, then paint flow properties are improved, but pigment and filler particles settle during storage or shipping
Solution Approach 1:
The patent utilizes temperature-responsive polymer segments that change their solubility and conformation with temperature, creating a dynamic thickening effect that adapts to storage conditions. This ensures particles remain suspended during storage while maintaining proper flow properties during application.
Solution Approach 2:
The patent introduces dynamic molecular mechanisms where the thickener's hydrophobic groups can reversibly associate and dissociate based on temperature and concentration changes. This dynamic behavior allows the system to maintain particle suspension stability during storage while providing appropriate flow properties during application.
3Ease of operation
If conventional viscosity modifiers are used to balance high and low shear viscosities, then application properties are satisfied, but the system requires blends of multiple additives increasing complexity
Solution Approach 1:
The patent designs a multi-functional thickener that simultaneously provides both high-shear and low-shear viscosity modification through its complex molecular architecture. The polymer contains segments that interact differently at various shear rates, eliminating the need for multiple separate additives and simplifying the formulation.
Solution Approach 2:
The patent creates a composite polymer structure integrating multiple functional segments including hydrophobic groups for association, hydrophilic segments for solubility, and temperature-responsive units for stability. This single composite material replaces traditional blends of multiple viscosity modifiers, reducing formulation complexity while maintaining performance.
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 nonionic associative thickener maintains viscosity stability across a temperature range of 25°C to 50°C, enhancing application properties by preventing sagging and settling, and resisting changes in viscosity upon addition of surfactant-containing colorants.
Implementation Method 1
The associative thickeners operate to thicken systems to which they are added by non-specific associations, such as adsorption on surfaces or aggregation in solution akin to micellization, between the hydrophobic groups on the thickener molecules and moieties on the other components in the system
Data Source
AI summary
Nonionic associative thickeners are provided having a nonionic water soluble polymer backbone containing vinyl addition polymer. The nonionic water soluble polymer backbone has at least two pendant polymeric chains attached to the nonionic water soluble polymer backbone. The pendant polymeric chains have terminal chain segments containing polyoxypropylene units. The nonionic associative thickeners are useful for modifying the rheology of compositions including aqueous compositions, such as latex containing compositions.