Photocatalyst Coated Body With Intermediate Layer For Exterior Materials
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Solution Overview
Problem
Photocatalyst coated films on exterior building materials face issues with interference colors, gloss changes, and insufficient adhesiveness due to film thickness and direct contact with substrates, leading to compromised photocatalytic performance and weather resistance.
Innovation Solution
A photocatalyst coated body with an intermediate layer of nanosize inorganic oxide particles and a photocatalyst layer of micron-sized particles, where the photocatalyst particles are dispersed to prevent glare and maintain adhesiveness, ensuring a film thickness of 0.3 μm to 1.5 μm for optimal performance and appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the film thickness is increased to 0.3-1 μm to improve photocatalytic performance, then photocatalytic activity is enhanced, but interference colors occur and gloss value increases significantly
Solution Approach 1:
A clear coat layer is introduced as an intermediary between the painted surface and the photocatalyst coated film. This intermediate layer acts as a buffer that prevents direct optical interference between the photocatalyst particles and the painted surface, thereby eliminating interference colors and gloss changes while maintaining the photocatalytic functionality of the outer layer
Solution Approach 2:
The solution adds a new dimensional layer (the clear coat) between existing layers rather than adjusting the thickness of the photocatalyst layer itself. This dimensional addition resolves the optical interference issue without compromising the photocatalytic performance that depends on the outer layer thickness
2Reliability
If the film thickness is increased to 2 μm or more to improve photocatalytic performance, then photocatalytic activity is enhanced, but the coated film appears whitened
Solution Approach 1:
The clear coat layer serves as a transparent intermediary that allows light to pass through to the photocatalyst particles without being scattered by excessive particle concentration near the surface. This maintains natural appearance while enabling sufficient photocatalytic activity through the particles located in the outer photocatalyst coated film
3Shape
If the film thickness is reduced to 0.3 μm or less to improve appearance, then interference colors and gloss changes are reduced, but sufficient photocatalytic performance cannot be obtained
Solution Approach 1:
The clear coat layer adds a new dimensional space that separates the optical function (maintaining appearance) from the photocatalytic function (requiring sufficient particle thickness). The clear coat handles the optical dimension by providing a smooth, interference-free interface, while the photocatalyst coated film in the outer dimension provides sufficient thickness for photocatalytic activity
4Device complexity
If the photocatalyst coated film is formed directly on the painted surface to simplify structure, then manufacturing is simplified, but adhesiveness is insufficient and substrate deterioration occurs
Solution Approach 1:
The clear coat layer acts as a chemical and mechanical intermediary between the painted surface and the photocatalyst coated film. It provides adhesion promotion by creating a compatible interface with both layers, preventing direct contact that would cause substrate deterioration, while still allowing the photocatalyst to function effectively in the outer layer
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 achieves sufficient photocatalytic activity, adhesiveness, and weather resistance while preventing interference colors and gloss changes, maintaining a good appearance and functional effectiveness.
Implementation Method 1
By utilizing an activity of the photocatalyst excited by a light energy, various harmful substances can be decomposed
Implementation Method 2
by hydrophilizing a film surface coated with a photocatalyst, a dirt which is attached to the film surface can be readily washed out with water
Data Source
AI summary
The present invention provides a photocatalyst coated body which can realize a sufficient photocatalytic activity and adhesiveness with a substrate, without significantly impairing an appearance of a substrate, especially an exterior building material. The photocatalyst coated body has a structure including a substrate, an intermediate layer formed on the substrate, and a photocatalyst layer formed on the intermediate layer. The intermediate layer includes inorganic oxide particles having an average particle diameter of nanosize. The photocatalyst layer includes photocatalyst particles having an average particle diameter of more than 0 μm to less than 10 μm and inorganic oxide particles having an average particle diameter of nanosize. A sum of a film thickness of the intermediate layer and a film thickness of the photocatalyst layer is 0.3 μm or more to 1.5 μm or less.