ITO Particle Dispersion for Heat Shielding
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Solution Overview
Problem
Existing heat-ray shielding particle dispersions face challenges in achieving high visible light transmittance and transparency while maintaining effective heat-ray shielding properties, and often require complex manufacturing processes or unsuitable dispersants for specific applications.
Innovation Solution
A heat-ray shielding particle dispersion using indium tin oxide (ITO) particles with a BET specific surface area of 20-75 m^2/g, dispersed in a solvent containing 60% or more water and a phosphate ester-based, polyglycerin-based, polyvinylpyrrolidone-based, or polyacrylate-based dispersant, which allows for high visible light transmittance and transparency similar to solvent-based dispersions without the environmental and handling issues of solvent-based systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solvent-based dispersion is used for heat-ray shielding, then heat-ray shielding properties are improved, but environmental and health hazards increase
Solution Approach 1:
The patent changes the fundamental parameter of the dispersion medium from organic solvent to water-based solvent. This substitution maintains the heat-ray shielding functionality of ITO particles while eliminating the toxicological and environmental problems associated with organic solvents, thereby resolving the contradiction between performance and safety
2Ease of manufacture
If ITO particles are dispersed in water without organic ligands, then manufacturing complexity is reduced, but dispersion stability deteriorates
Solution Approach 1:
The patent introduces a water-soluble dispersant as an intermediary substance that mediates between the hydrophobic ITO particles and the aqueous environment. This dispersant adsorbs onto the particle surfaces, providing steric or electrostatic stabilization that prevents aggregation, thus maintaining dispersion stability while avoiding the need for complex organic ligand coordination procedures
3Reliability
If high concentration of ITO particles is used, then heat-ray shielding effectiveness is improved, but visible light transmittance decreases
Solution Approach 1:
The patent employs ITO particles with specifically controlled local properties - namely, optimized particle size distribution and surface characteristics. By controlling the particle size to be in the fine particle range and optimizing the surface area to volume ratio, the dispersion achieves efficient infrared reflection at lower concentrations, thereby maintaining high visible light transmittance while providing effective heat-ray shielding
4Stability of the object's composition
If phosphate ester-based dispersants are used, then dispersion stability is improved, but compatibility with certain applications may be limited
Solution Approach 1:
The patent selects dispersants with multi-functional characteristics that provide both stabilization and broad application compatibility. The chosen water-soluble dispersants possess functional groups that can interact with various substrates and coating formulations, enabling the heat-ray shielding dispersion to be universally applied across different automotive and building material applications without requiring formulation adjustments
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 dispersion achieves excellent heat-ray shielding properties with high visible light transmittance and transparency, simplifying the manufacturing process and avoiding the complexities of coordinating organic ligands or eliminating protective groups, making it suitable for applications like automotive and building materials.
Implementation Method 1
ITO particles having a heat-ray shielding capability... a transmittance at a wavelength of 1,200 nm is 60% or less and a visible light transmittance is 85% or more
Implementation Method 2
a dispersant... the ITO particles are dispersed in water... excellent in dispersion stability (aggregation preventive property)
Data Source
AI summary
Provided is a heat-ray shielding particle dispersion which contains: ITO particles having a heat-ray shielding capability; a solvent containing 60% by mass or more of water; and a dispersant. The ITO particles have a BET specific surface area of 20 m2/g or more, have a blue or dark blue tone represented by an L value of 50 or less and a<0 and b<0 in the Lab color system, and are contained in an amount of 1-90% by mass with respect to 100% by mass of the dispersion. The solvent is a component obtained by removing the heating residue from the heat-ray shielding particle dispersion, and is contained in an amount of 6.1-99.0% by mass with respect to 100% by mass of the dispersion. The dispersant is at least one kind among a phosphate ester-based dispersant, a polyglycerin-based dispersant, a polyvinylpyrrolidone-based dispersant, a polyoxyethylene-polyoxypropylene condensate-based dispersant, and a polyacrylate-based dispersant, and the content of the active ingredient of the dispersant is 0.05-80 parts by mass with respect to 100 parts by mass of the ITO particles.