Surface-Modified Indium Tin Oxide for Heat-Ray Shielding

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Solution Overview

Problem

Conventional indium tin oxide (ITO) powders used for heat-ray shielding have inferior heat-ray shielding properties due to their white color and low (a·b)/L ratio in the Lab colorimetric system, which limits their effectiveness in enhancing heat-ray shielding effects.

Innovation Solution

A heat-ray shielding composition utilizing a surface-modified indium tin oxide powder with a bright yellow to persimmon (reddish brown or orange-red) tone, achieved by co-precipitating indium tin hydroxide and adjusting the pH within a specific range, followed by drying and firing to enhance crystallinity and BET specific surface area, resulting in a navy blue or cobalt blue tone with improved heat-ray shielding properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional white indium tin oxide powder is used for heat-ray shielding, then the material can be produced through simple co-precipitation methods, but the heat-ray shielding effect is inferior due to white color and low (a·b)/L ratio

Engineering Contradiction:
Improveheat-ray shielding effectVSAvoidproduction method simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the color parameters of ITO powder by controlling pH during co-precipitation. By adjusting pH to specific ranges (4.0-9.3 for yellow tone, 9.4-11.0 for orange-red tone), the powder achieves enhanced heat-ray shielding effect through color modification rather than changing the basic production method

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies surface modification treatment to specific regions of the ITO powder particles. By treating only the surface layer with modifying agents, the powder achieves improved heat-ray shielding properties while maintaining the overall simplicity of the production process

Inventive Principle:
Principle #3Local quality

2Reliability

If ITO powder with bright yellow to persimmon tone is produced through controlled co-precipitation, then heat-ray shielding effect is enhanced, but the production process becomes more complex due to pH control requirements

Engineering Contradiction:
Improveheat-ray shielding effectVSAvoidproduction process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention establishes specific pH ranges (4.0-9.3 for yellow tone, 9.4-11.0 for orange-red tone) as control parameters during co-precipitation. By defining these parameter ranges, the complex process of color-controlled ITO production becomes systematic and reproducible, managing complexity through parameter specification

Inventive Principle:
Principle #35Parameter changes

3Reliability

If ITO powder is surface-modified to achieve navy blue or cobalt blue tone, then heat-ray shielding properties are improved, but the production process requires additional modification steps

Engineering Contradiction:
Improveheat-ray shielding propertiesVSAvoidproduction process steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention performs surface modification treatment as a preliminary step during or after the co-precipitation process. By conducting the modification treatment in advance or immediately after precipitation, the process avoids subsequent complex steps, achieving improved heat-ray shielding properties through timely surface treatment

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention creates composite structures by combining ITO powder with surface-modifying agents. This composite approach allows the base ITO material to maintain its conductivity while the surface modification layer provides enhanced heat-ray shielding properties, achieving dual functionality

Inventive Principle:
Principle #40Composite materials

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 surface-modified indium tin oxide powder exhibits high visible light transmittance, excellent transparency, and suppressed film whitening, while maintaining low sunlight transmittance, thereby achieving enhanced heat-ray shielding effects with high crystallinity and conductivity.

Implementation Method 1

an indium-containing aqueous solution is mixed with a tin-containing aqueous solution to co-precipitate indium tin hydroxide

Methodology Applied
Scientific EffectCo-precipitation: Coprecipitation

Implementation Method 2

firing the obtained co-precipitate

Methodology Applied
Scientific EffectFiring: Heat Treatment

Data Source

PatentEP2495217B1Heat-ray shielding composition and method for producing the same
Publication Date: 2018.12.12 MITSUBISHI MATERIALS ELECTRONICS CHEM CO LTD
  • EP2495217B1 patent drawingFigure 1
  • EP2495217B1 patent drawingFigure 2
  • EP2495217B1 patent drawingFigure 3

AI summary

Disclosed are a heat-ray shielding composition including an indium tin oxide powder which has a BET specific surface area of 40 m2/g or more and a navy blue or cobalt blue (L = 30 or less, a < 0, b < 0 in the Lab colorimetric system) tone, and preferably a heat-ray shielding composition, wherein the indium tin oxide powder contained in the composition is an indium tin oxide powder which is surface-modified by firing indium tin hydroxide having bright yellow to persimmon (reddish brown or orange-red) tone, or an indium tin oxide powder which is surface-modified by firing indium tin oxide having bright yellow to persimmon (reddish brown or orange-red) tone; and a method for producing the same.