Photocatalyst Coating for Organic Substrates

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Solution Overview

Problem

Conventional photocatalyst-coated bodies using organic substrates face degradation due to photocatalytic activity, requiring additional protective layers that increase manufacturing time and cost, while also compromising on weather resistance and noxious gas decomposability.

Innovation Solution

A photocatalyst-coated body with a specified composition comprising photocatalyst particles and inorganic oxide particles in a specific mass ratio, minimizing hydrolyzable silicone and surfactant content, which enhances weather resistance, noxious gas decomposability, ultraviolet absorptivity, transparency, and film strength without corroding organic substrates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an adhesive layer is provided between the photocatalyst layer and organic substrate to prevent substrate deterioration, then substrate protection is improved, but device complexity and manufacturing time increase

Engineering Contradiction:

Improvesubstrate protectionVSAvoidcoating structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the intermediate adhesive layer from the coating structure by developing a photocatalyst composition that inherently protects organic substrates through controlled formulation (specific inorganic oxide particles with 10-40 nm diameter and specific photocatalyst-to-binder ratio), thereby simplifying the coating structure to just the photocatalyst layer directly on the substrate while maintaining substrate protection

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary mechanism at the molecular/compositional level within the photocatalyst layer itself - using specifically sized inorganic oxide particles (10-40 nm) that act as a protective mediator between the photocatalyst and substrate, preventing direct harmful interaction while allowing the photocatalyst to function, thus eliminating the need for a separate adhesive layer

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a photocatalyst layer is applied directly to organic substrate to simplify structure, then device complexity is reduced, but substrate deterioration occurs due to photocatalytic activity

Engineering Contradiction:

Improvecoating structureVSAvoidsubstrate deterioration

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the physical and chemical parameters of the photocatalyst composition - specifically controlling particle size (10-40 nm), composition ratios (photocatalyst to binder), and using specific inorganic oxides - to modify the photocatalytic activity characteristics so that it protects the substrate rather than deteriorating it, allowing direct application without adhesive layers

Inventive Principle:

Principle #35Parameter changes

3Object-generated harmful factors

If high TiO2 content is used to enhance photocatalytic activity, then noxious gas decomposability is improved, but transparency deteriorates due to increased light scattering

Engineering Contradiction:

Improvenoxous gas decomposabilityVSAvoidtransparency

Core Design Contradiction:

Object-generated harmful factorsVSIllumination intensity

Solution Approach 1:

The patent changes the particle size parameter to 10-40 nm diameter, which is small enough to reduce light scattering and maintain transparency while still providing sufficient photocatalytic surface area for effective noxious gas decomposition, resolving the trade-off between catalytic activity and optical clarity

Inventive Principle:

Principle #35Parameter changes

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 solution provides a photocatalyst-coated body with superior weather resistance, noxious gas decomposability, and coating properties while preventing substrate corrosion, eliminating the need for intermediate protective layers and reducing manufacturing costs.

Implementation Method 1

Photocatalysts such as titanium oxide have been recently utilized in various applications such as exterior materials for buildings. Employment of the photocatalyst makes it possible to harness light energy to decompose various types of noxious substances

Methodology Applied

Scientific EffectPhotocatalysis: Catalysis

Implementation Method 2

a photocatalyst-coated body which is superior in weather resistance, noxious gas decomposability, and various coating properties (such as ultraviolet absorptivity, transparency and film strength)

Methodology Applied

Scientific EffectUltraviolet absorptivity: Absorption (EM radiation)

Data Source

PatentEP2127762B1Photocatalyst-coated object and photocatalytic coating fluid therefor

Publication Date: 2017.01.25 TOTO LTD

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AI summary

There is disclosed a photocatalyst-coated body which is superior in weather resistance, noxious gas decomposability, and various coating properties (such as ultraviolet absorptivity, transparency and film strength) while preventing corrosion of a substrate (in particular an organic substrate), and a photocatalyst coating liquid therefor. The photocatalyst-coated body comprises a substrate and a photocatalyst layer provided on the substrate. The photocatalyst layer comprises photocatalyst particles of 1 part or more by mass and less than 20 parts by mass; inorganic oxide particles of 70 parts or more by mass and less than 99 parts by mass; and a hydrolyzable silicone of zero parts or more by mass and less than 10 parts by mass, provided that a total amount of the photocatalyst particles, the inorganic oxide particles and the hydrolyzable silicone is 100 parts by mass.