Photocatalyst Laminate With Core-Shell Nanoparticles for UV Protection
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Solution Overview
Problem
Photocatalyst coatings on organic substrates degrade due to photocatalytic action and UV exposure, leading to loss of photocatalytic function and hydrophilicity over time, especially when exposed to outdoor weather.
Innovation Solution
A photocatalyst laminate comprising an undercoat layer with core/shell nanoparticles of tetragonal titanium oxide solid-solution nanoparticles having tin and manganese in solid solution, coated with silicon oxide, and a photocatalyst layer, which provides UV-shielding and maintains photocatalytic function and hydrophilicity even after long-term outdoor exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an undercoat layer containing organic UV absorbers is used to protect the substrate from UV degradation, then the substrate is protected from UV damage, but the photocatalytic function is gradually lost and surface hydrophilicity is lowered over time
Solution Approach 1:
The patent changes the chemical composition parameter of the UV absorber from organic compounds to inorganic nanoparticles (zinc oxide and/or titanium oxide). This parameter change maintains UV shielding capability while preventing the degradation of photocatalytic function and surface hydrophilivity that occurs with organic UV absorbers during outdoor exposure.
Solution Approach 2:
The patent creates a composite undercoat layer combining inorganic UV-absorbing nanoparticles (zinc oxide and/or titanium oxide) with resin components. This composite material approach integrates UV protection and photocatalytic function compatibility, as the inorganic nanoparticles do not interfere with the overcoat layer's photocatalytic activity while providing effective UV shielding.
2Ease of operation
If a photocatalyst coating is directly formed on an organic substrate, then the substrate surface becomes hydrophilic and gains self-cleaning properties, but the substrate surface is decomposed and degraded by photocatalytic action
Solution Approach 1:
The patent introduces an undercoat layer as an intermediary between the organic substrate and the photocatalyst-containing overcoat layer. This intermediate layer protects the substrate from direct contact with and degradation by the photocatalyst, while still allowing the overcoat layer to exhibit photocatalytic self-cleaning properties on its outer surface.
Solution Approach 2:
The patent divides the coating system into two distinct layers: an undercoat layer for substrate protection and an overcoat layer for photocatalytic activity. This segmentation allows each layer to perform its specific function independently, with the undercoat protecting the substrate and the overcoat providing self-cleaning capabilities.
3Reliability
If outdoor exposure is extended to improve weather resistance testing, then long-term durability is evaluated, but color fading and gloss degradation occur due to UV exposure
Solution Approach 1:
The patent changes the UV protection mechanism by using inorganic nanoparticles with different optical properties compared to organic UV absorbers. These inorganic particles provide UV shielding without the side effects of color fading and gloss degradation, maintaining aesthetic appearance even after extended outdoor exposure.
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 laminate maintains esthetic appearance, anti-fouling properties, and photocatalytic function while protecting the substrate from degradation by photocatalytic and UV-induced damage, ensuring high weather resistance and hydrophilicity.
Implementation Method 1
an undercoat layer comprising (A) 100 parts by weight of a resin component and (B) 0.1 to 50 parts by weight of core/shell nanoparticles each consisting of a core in the form of a tetragonal titanium oxide solid-solution nanoparticle having tin and manganese incorporated in solid solution and a shell of silicon oxide around the core
Implementation Method 2
photocatalyst coatings formed on the surface of various substrates contain photocatalysts such as titanium oxide which render the substrate surface hydrophilic upon light exposure, the coatings have functions of readily washing away surface stains with water and decomposing various organic compounds
Implementation Method 3
photocatalysts such as titanium oxide which render the substrate surface hydrophilic upon light exposure
Data Source
AI summary
A photocatalyst laminate which is composed of an undercoat layer provided on a substrate and a photocatalyst layer laminated on the surface of the undercoat layer. The undercoat layer contains (A) 100 parts by mass of a resin component and (B) 0.1-50 parts by mass of fine core-shell particles, each of which has a core that is formed of a fine tetragonal titanium oxide solid solution particle wherein tin and manganese are solid-solved and a shell that is formed from silicon oxide on the outside of the core. This photocatalyst laminate is not susceptible to decrease in the photocatalyst function even under outdoor exposure for a long period of time, and is thus capable of providing a coated article that exhibits excellent weather resistance.