Decorative Sheet Weatherability via Al-Si Coated TiO2
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Solution Overview
Problem
Decorative sheets containing titanium oxide pigments face weatherability issues due to photocatalytic degradation, leading to delamination and color changes, as existing ultraviolet absorbers can absorb visible light, causing yellowing and contamination, and surface treatments of titanium oxide particles often result in poor dispersion.
Innovation Solution
A decorative sheet with a substrate containing titanium oxide particles coated with Al and Si elements in a specific mass ratio, combined with an ultraviolet absorber in the surface protective layer, ensuring excellent dispersion and weatherability without limiting design options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the content of ultraviolet absorber in the surface protective layer is increased to prevent delamination and enhance ultraviolet absorption capacity, then the weatherability is improved, but the surface protective layer absorbs violet to blue light causing yellowing and deteriorating the design of the decorative sheet
Solution Approach 1:
The patent changes the chemical parameters of the ultraviolet absorber by specifying particular compounds (benzotriazole type with formula (1) or triazine type with formula (2)) and their molecular structures, which have different absorption characteristics compared to conventional ultraviolet absorbers. This allows selective absorption of ultraviolet light while minimizing absorption of visible light in the violet to blue range, thereby preventing yellowing while maintaining weatherability.
2Reliability
If the content of ultraviolet absorber is increased to prevent delamination, then the weatherability is improved, but the ultraviolet absorber may bleed from the surface protective layer causing contamination or change in appearance
Solution Approach 1:
The patent uses a specific resin component as an intermediary matrix to embed the ultraviolet absorber molecules. The resin component (polymerizable monomer or polymer with formula (3)) provides a stable environment that anchors the ultraviolet absorber, preventing it from migrating or bleeding out of the surface protective layer, while still allowing the absorber to function effectively.
3Reliability
If white pigment particles with surface treatment are used to inhibit photocatalytic action, then the weatherability is improved, but the particles are poorly dispersed in resin resulting in ineffective ultraviolet absorption
Solution Approach 1:
The patent applies local quality modification by coating only the surface of the titanium oxide particles with specific inorganic materials (alumina, silica, or alumino-silicate) rather than treating the bulk material. This surface coating provides uniform dispersion in the resin while maintaining the photocatalytic inhibition function, creating a gradient structure where the core retains titanium oxide properties and the surface provides dispersion stability.
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 enhanced weatherability and prevents yellowing, ensuring the decorative sheet maintains its appearance and performance over time while allowing for effective ultraviolet protection.
Implementation Method 1
adds an ultraviolet absorber to a surface protective layer of a decorative sheet, which is to be exposed to light, thereby inhibiting the photocatalytic action of titanium oxide caused by ultraviolet light
Implementation Method 2
Titanium oxide exhibits a strong oxidizing power upon its photoexcitation. When a decorative sheet containing titanium oxide is used for an exterior member, the photocatalytic action of the titanium oxide can cause decomposition or a chemical reaction of a resin contained in the substrate
Implementation Method 3
the use of white pigment particles, composed of titanium oxide, whose surfaces are treated e.g. with an inorganic metal oxide in order to inhibit the photocatalytic action of the titanium oxide
Data Source
Figure 1~2
AI summary
There are provided a decorative sheet which has excellent weatherability and in which white pigment particles are dispersed well, and a decorative material using the decorative sheet. The decorative sheet includes at least a substrate and a surface protective layer. The surface protective layer contains an ultraviolet absorber, and the substrate contains white pigment particles. The white pigment particles are titanium oxide particles having a coating containing Al element and Si element and formed on part or the whole of their surfaces, and contain Ti, Al and Si elements in the following mass ratio: when Ti is taken as 1, A1 is not less than 0.02 and less than 0.20, and Si is more than 0.002 and not more than 0.070.