Multistage Polymer Particles for Waterborne Paint Open Time
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Solution Overview
Problem
Waterborne acrylic paints have a short open time, which limits the time available for refreshing a freshly coated surface without causing defects like lap lines, and conventional methods to extend open time often compromise flow-and-leveling properties or increase water sensitivity and VOC emissions.
Innovation Solution
Aqueous dispersion of multistage polymer particles containing an oligomer with specific structural units of alkoxylated (meth)acrylate, which are prepared through multistage free-radical polymerization, providing improved flow-and-leveling properties and extended open time without the use of volatile organic compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional open time extenders (OTEs) are added to aqueous acrylic polymer binders, then open time is extended, but water sensitivity increases and stain and scrub resistance decrease
Solution Approach 1:
The invention changes the chemical parameters of the polymer binder by incorporating polyethylene glycol units with specific molecular weights (100-10,000 Da) at controlled concentrations (0.1-10%). This modifies the polymer's hydrophilicity and intermolecular forces, extending open time through enhanced chain mobility and reduced water sensitivity, eliminating the need for conventional OTEs
Solution Approach 2:
The invention creates a composite polymer structure combining acrylic or vinyl acrylic polymer chains with embedded polyethylene glycol units. This composite architecture integrates the beneficial properties of both components: the polymer provides film formation and adhesion, while the PEG units extend open time and reduce water sensitivity
2Shape
If viscosity is reduced at low shear rates to improve flow-and-leveling, then coating defects are reduced, but sagging and running occur during application
Solution Approach 1:
The invention creates a dynamic viscosity system where the polymer's flow properties change with shear rate. At low shear rates (during application), the polymer maintains higher viscosity for sag resistance. At higher shear rates (during spreading), the polymer exhibits shear thinning for improved flow-and-leveling, eliminating coating defects
3Duration of action of moving object
If glycols are used to increase open time, then open time is extended, but volatile organic compounds (VOCs) are introduced which are less environmentally friendly
Solution Approach 1:
The invention replaces conventional volatile organic compound-based open time extenders with water-soluble polyethylene glycol units integrated into the polymer structure. These PEG units provide sustained open time extension through their hydrophilic nature and hydrogen bonding capabilities, eliminating VOC emissions while maintaining environmental friendliness
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 multistage polymer particles enhance the flow-and-leveling properties and extend the open time of waterborne acrylic paints, allowing for smoother applications and reduced defects, while maintaining environmental sustainability by avoiding VOCs.
Implementation Method 1
The aqueous dispersion of the present invention is prepared from polymerization of monomers comprising an alkoxylated (meth)acrylate
Data Source
AI summary
An aqueous dispersion of multistage polymer particles comprising a specific oligomer prepared from polymerization of monomers comprising an alkoxylated (meth)acrylate providing aqueous coating compositions with both good flow-and-leveling property and extended open time.