Titania Sol Preparation via Controlled Sol-Gel Reaction
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Solution Overview
Problem
Existing methods for preparing titania sol for high refractive coatings face challenges such as low solid content, particle aggregation, and difficulty in achieving stable dispersion due to titania's chemical stability and poor solubility, particularly in achieving spherical particles of several nanometer size.
Innovation Solution
A sol-gel reaction method is employed, controlling peptization and crystal growth by solvent removal at high temperature, using specific alkoxides and catalysts to produce titania sol with monodisperse secondary particles of 200 nm or less, allowing high concentration dispersion and stable sol formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If titania is dispersed in a solvent to form a sol, then it can be used as a coating material, but the solid content is too low to be used as a filler for a high refractive hard coating layer
Solution Approach 1:
The patent changes the physical and chemical parameters of the titania particles by controlling the sol-gel reaction conditions, including temperature, pH, and catalyst concentration, to achieve monodisperse particles with controlled size distribution and high solid content without aggregation
Solution Approach 2:
The patent uses a specific solvent system and catalyst as intermediaries to facilitate the sol-gel reaction, enabling uniform dispersion of titania particles at high concentrations while preventing aggregation during the coating process
2Quantity of substance
If water is removed to increase the solid content, then the solid content increases, but aggregations of particles occur and the particles are enlarged
Solution Approach 1:
The patent controls the removal of solvent by adjusting temperature and pressure parameters during the sol-gel reaction, enabling solid content increase while maintaining particle size uniformity through controlled evaporation and condensation processes
Solution Approach 2:
The patent performs preliminary formation of monodisperse titania particles with controlled size distribution before the coating process, ensuring that when solvent is removed to increase solid content, the particles remain uniformly dispersed without aggregation or enlargement
3Ease of manufacture
If titania is made into a sol through sol-gel reaction, then the titania sol is easily prepared, but the solid content must be low to make a stable sol
Solution Approach 1:
The patent optimizes the sol-gel reaction parameters including temperature, pH, catalyst concentration, and solvent type to achieve stable sol formation at high solid content, making the process easy to manufacture while maintaining particle stability
Solution Approach 2:
The patent uses specific catalysts and solvent systems as intermediaries to facilitate the sol-gel reaction, enabling easy preparation of high solid content stable sols without particle aggregation or instability
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 method achieves a high solid content titania sol with monodisperse particles, enhancing the properties of the coating layer, including refractive index, transparency, hardness, and dispersity, suitable for applications in glasses and goggles.
Implementation Method 1
The sol-gel reaction has a merit such that the titania sol is easily prepared by hydrolysis reaction of a metal halide or an alkoxide
Implementation Method 2
an acid catalyst is added to the reactant solution, and the sol-gel reaction and removing the solvent for reaction are simultaneously conducted
Implementation Method 3
the solvent for reaction is removed from the reactor, and the peptization and crystal growth of the primary titania particle are caused by adding the acid catalyst
Data Source
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AI summary
The present invention relates to a titania sol, a method of preparing the same, and a coating composition including the same. More specifically, it relates to a titania sol prepared by elevating the temperature of a reactant solution including a precursor of titania in a solvent for reaction to a reaction temperature, adding an acid catalyst to the reactant solution and conducting a sol-gel reaction while removing the solvent for reaction therefrom, and drying the prepared titania sol and re-dispersing the dried titania in a solvent for dispersion, a method of preparing the same, and a coating composition including the same.