Fluorescent Polymer Dispersion Viscosity and Stability
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Solution Overview
Problem
Existing pigment-free, aqueous polymer dispersions labeled with fluorescent dyes lack long-term stability and pumpability, often settling or flocculating during storage and handling, which hinders their use in various applications such as coating materials and adhesives, and there is a lack of efficient processes for producing these dispersions with reduced energy expenditure and mixing steps.
Innovation Solution
A pigment-free, aqueous polymer dispersion with a viscosity of 500 to 900 mPas, comprising 1 to 99% water-soluble polymer particles (0.01 to 1 μm), 1 to 20% polymer particles with fluorescent dyes (1 to 100 μm), and 0.001 to 3% thickener, stabilized with hydrophobic surface-active compounds and other additives, is produced using a process that homogeneously mixes these components in water, ensuring stability and pumpability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If thickeners are added to increase viscosity to prevent settling, then long-term stability is improved, but pumpability deteriorates due to excessive energy expenditure
Solution Approach 1:
The patent optimizes the viscosity parameter to a specific range (500-900 mPas) that simultaneously provides long-term stability against settling and maintains pumpability. This parameter change resolves the contradiction by finding the optimal viscosity window that prevents both settling and excessive energy consumption during pumping operations.
Solution Approach 2:
The patent employs shear-thinning polymer particles that dynamically adjust their viscosity based on applied shear stress. At low shear rates (storage condition), the dispersion maintains high viscosity to prevent settling. At high shear rates (pumping condition), the viscosity decreases automatically, reducing energy expenditure for pumping without requiring additional thickeners.
2Stability of the object's composition
If protective colloids are absorbed on particle surfaces, then particle stability is improved, but thickening effect is lost due to lack of free protective colloids in solution
Solution Approach 1:
The patent uses composite polymer particles that combine protective colloid functionality within the particle structure itself. The protective colloids are incorporated into the polymer matrix during suspension polymerization, creating a composite structure where the particle provides both stability and thickening effects simultaneously, eliminating the need for separate free protective colloids in the continuous phase.
Solution Approach 2:
The protective colloids are nested within the polymer particle structure during synthesis. The patent describes incorporating protective colloids into the polymer particles via suspension polymerization, creating a hierarchical structure where the protective colloid is embedded within the particle, providing both surface stability and bulk thickening properties.
3Adaptability or versatility
If pigment-free aqueous polymer dispersions are prepared separately for different applications, then versatility is improved, but manufacturing complexity increases due to multiple mixing steps
Solution Approach 1:
The patent creates a universal base dispersion formulation that can serve multiple applications (coating materials, adhesives, sealants, printing inks, paper coating slips, and paper sizing agents). By formulating a single versatile dispersion with optimized properties, the patent eliminates the need for separate preparations for different applications, reducing manufacturing complexity while maintaining broad adaptability.
Solution Approach 2:
The patent prepares polymer particles with pre-defined properties (size distribution, fluorescent dye incorporation, protective colloid content) before final application. This preliminary preparation of standardized particles allows for direct use in multiple applications without requiring additional mixing or formulation steps at the point of use, simplifying the overall manufacturing process.
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 resulting polymer dispersion exhibits high long-term stability, preventing settling for at least 1.5 months and maintaining pumpability without excessive energy expenditure, allowing for efficient use in diverse applications and simplifying production by reducing mixing steps.
Implementation Method 1
aqueous polymer dispersions labeled with fluorescent dyes
Implementation Method 2
volume-average particle size of 1 to 100 μm determined by light scattering
Implementation Method 3
stabilized with hydrophobic surface-active compounds
Data Source
AI summary
Pigment-free aqueous polymeric dispersion labelled with fluorescent dyes and having a Brookfield (spindle 3, 23°C) viscosity of 500 to 900 mPas, containing, all based on the solids content of the polymeric dispersion, (A) 1% to 99% by weight of at least one kind of water-soluble and/or dispersible polymers, (B) 1% to 20% by weight of at least one kind of water-dispersible polymeric particles containing at least one fluorescent dye, and (C) 0.001% to 3% by weight of at least one thickener; its production; and its use.