Polyvinyl Acetal Microparticles for Stable Aqueous Dispersion
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Solution Overview
Problem
Polyvinyl acetal resin fine particles in aqueous dispersion tend to coagulate and precipitate quickly in water-based mediums, making it difficult to maintain dispersion stability and form films with sufficient mechanical strength and flexibility without voids or irregularities.
Innovation Solution
Polyvinyl acetal fine particles with an ionic functional group, specifically carboxyl, sulfonic acid, or sulfonic acid salts, are developed, having a volume average particle size between 10 nm to 100 μm and a narrow particle size distribution, which enhances dispersion stability and allows for the formation of strong and flexible films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polyvinyl acetal resin fine particles are dispersed in water-based medium, then the dispersion initially forms, but the particles coagulate and precipitate quickly, making it difficult to maintain dispersion stability
Solution Approach 1:
The invention changes the chemical parameter of the polyvinyl acetal resin by introducing ionic functional groups (carboxyl, sulfonic acid, or their salts), which fundamentally alters the interaction between particles and the aqueous medium, enabling stable dispersion without coagulation
Solution Approach 2:
The invention creates a composite structure by combining polyvinyl acetal resin with ionic functional groups, resulting in a material that exhibits both the desired film-forming properties of polyvinyl acetal and the dispersion stability of ionic compounds in aqueous environments
2Stability of the object's composition
If conventional dispersants are used to improve dispersion stability, then dispersibility increases, but the pH becomes alkaline (pH ≈ 9) and precipitation occurs when pH approaches neutral or acidic compounds are added
Solution Approach 1:
The polyvinyl acetal resin itself provides the dispersing function through its ionic functional groups, eliminating the need for external dispersants and their associated pH limitations. The resin serves both as the structural component and the dispersing agent
Solution Approach 2:
The invention changes the pH independence parameter by incorporating ionic functional groups that maintain electrostatic repulsion and steric stabilization across a wide pH range, allowing stable dispersion from acidic to alkaline conditions without precipitation
3Strength
If polyvinyl acetal resin is used as binder dissolved in organic solvent, then good film formation is achieved, but environmental pollution and toxicity issues arise
Solution Approach 1:
The invention changes the solvent parameter from organic to aqueous by modifying the polyvinyl acetal resin with ionic functional groups, enabling the resin to disperse in water while maintaining film-forming capabilities, thus eliminating organic solvent pollution and toxicity
Solution Approach 2:
The invention utilizes the phase transition capability of the aqueous dispersion to form a continuous film upon water evaporation, transitioning from a dispersed aqueous phase to a solid film phase, achieving good film formation without organic solvents
4Manufacturing precision
If polymer fine particles with small particle size are used, then film uniformity improves, but particle size control and distribution narrowing become more difficult
Solution Approach 1:
The invention performs preliminary action by controlling the particle size and distribution during the resin synthesis stage through ionic functional group incorporation, ensuring uniform small particle sizes before dispersion, which simplifies subsequent processing and ensures film uniformity
Solution Approach 2:
The invention changes the synthesis parameters by incorporating ionic functional groups during polymerization, which affects the nucleation and growth kinetics, resulting in naturally smaller and more uniformly distributed particles without requiring complex post-processing
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 particles exhibit excellent dispersion stability and form films with high mechanical strength and flexibility, preventing voids and irregularities, even when precipitates form, and can be readily redispersed, improving the application of polyvinyl acetal resin in various fields.
Implementation Method 1
polyvinyl acetal fine particles for an aqueous dispersion which exhibit excellent dispersion stability in a water-containing dispersion medium
Implementation Method 2
allow for formation of a film having sufficient mechanical strength and flexibility without voids and non-uniform structures
Data Source
AI summary
The present invention provides polyvinyl acetal fine particles for an aqueous dispersion which exhibit excellent dispersion stability in a water-containing dispersion medium, and allow for formation of a film having sufficient mechanical strength and flexibility without voids and non-uniform structures such as irregularities, and an aqueous dispersion of the polyvinyl acetal fine particles for an aqueous dispersion. The polyvinyl acetal fine particles for an aqueous dispersion, adapted for use as dispersoids in an aqueous dispersion, the polyvinyl acetal fine particles including a polyvinyl acetal resin with an ionic functional group, and having a volume average particle size of 10 nm to 100 μm, and a CV value of a volume-based particle size distribution of at most 40%.