Titanium Oxide Dispersion Stability via Composite Surface Treatment
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Solution Overview
Problem
Conventional organic solvent dispersions of titanium oxide particles suffer from poor stability, high viscosity, and low transparency, making them unsuitable for high-performance optical applications.
Innovation Solution
An organic solvent dispersion of titanium oxide particles with a surface treatment process using a silane coupling agent and 12-hydroxystearic acid, followed by solvent replacement, achieving a high content, low viscosity, and superior stability and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If titanium oxide particles are dispersed in organic solvent using conventional methods (silane coupling agent only), then the dispersion can be prepared, but the transparency is insufficient and viscosity increases gradually over time
Solution Approach 1:
The patent applies composite surface treatment by combining silane coupling agent and 12-hydroxystearic acid on titanium oxide particles. This composite approach creates a dual-function coating that simultaneously provides stability through silane bonding and transparency through proper refractive index matching, resolving the contradiction between reliability and manufacturing precision
Solution Approach 2:
The patent changes the surface treatment parameters by introducing 12-hydroxystearic acid in specific amounts (0.1-10 mmol per 100g titanium oxide) alongside the silane coupling agent. This parameter modification optimizes both stability and transparency, preventing the gradual viscosity increase while maintaining high transparency for optical applications
2Adaptability or versatility
If titanium oxide particles are dispersed in organic solvent, then the dispersion can be used for optical applications, but the viscosity is high and stability is poor
Solution Approach 1:
The silane coupling agent acts as an intermediary between the hydrophilic titanium oxide particles and the lipophilic organic solvent. It provides bonding sites that bridge the inorganic particle surface and the organic dispersion medium, enabling stable dispersion while maintaining applicability for optical materials like LED sealing resins and anti-reflection coatings
3Ease of manufacture
If conventional surface treatment with silane coupling agent is used, then dispersibility in organic solvent is improved, but transparency and stability are insufficient
Solution Approach 1:
The patent performs preliminary surface treatment by pre-coating titanium oxide particles with silane coupling agent and 12-hydroxystearic acid before dispersing in organic solvent. This preliminary action ensures proper surface modification that guarantees both ease of manufacture through good dispersibility and long-term stability in the final dispersion
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 results in a dispersion with titanium oxide particles that maintain their high refractive index and optical properties, suitable for applications like LED sealing resin and anti-reflection coatings.
Implementation Method 1
surface treating the inorganic oxide fine particles with a silane coupling agent is effective in order to modify the inorganic oxide fine particles to be lipophilic
Implementation Method 2
titania particles are employed preferably for increasing the refractive index of an optical material because they have a high refractive index
Implementation Method 3
Dispersions of particles of an inorganic oxide such as silica, alumina, zinc oxide, tin oxide, zirconia, and titania are employed in various industrial fields, particularly in the field of optics for modulating refractive index
Data Source
AI summary
The invention provides an organic solvent dispersion of titanium oxide particles in a content of 10% by weight or more in an organic solvent except methanol and ethanol, wherein the titanium oxide particles are surface-treated with a surface treating agent comprising a silane coupling agent having the general formula (I) (RO)n-Si-X4·n (I) wherein R is an alkyl group having carbon atoms of 1-4, n is 2 or 3, X is an alkyl, a fluoroalkyl, a vinyl or a (meth)acryloyloxyalkyl group, and 12-hydroxystearic acid, and wherein the titanium oxide particles in the organic solvent have a D50 in a range of 1 to 30 nm, and wherein the organic solvent dispersion has a transmittance of 2% or more at a wavelength of 500 nm and a transmittance of 70% or more at a wavelength of 800 nm, a viscosity of 10 mPa·s or less at a temperature of 25°C immediately after production while the increase in the viscosity is 40 mPa·s or less seven days after production as compared to that of the dispersion immediately after production.