Transfer Sheet Coating for UV Shielding and Metal Luster
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Solution Overview
Problem
Existing decorative sheets for exterior members, which include a substrate layer, affect the design expression of metal members due to their thickness and may not adequately leverage the luster of the metal, while also struggling to provide sufficient weather resistance against ultraviolet rays.
Innovation Solution
A transfer sheet comprising a releasing film with a transfer layer that includes a first and second protective layer and a pattern layer, where the low covered area has an ultraviolet ray transmittance of 1% or less and a visible light transmittance of 40% or more, allowing for excellent weather resistance and design expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of weather resistant agent is increased to reduce ultraviolet ray transmittance, then weather resistance is improved, but yellowing is induced and visible light transmittance decreases
Solution Approach 1:
The protective layer is divided into multiple layers (first protective layer, second protective layer, third protective layer) with different functions. The first and second protective layers contain weather resistant agents for UV protection, while the third protective layer is designed to be transparent to maintain visible light transmittance and prevent yellowing. This segmentation allows each layer to specialize in specific functions without compromising overall performance.
Solution Approach 2:
Different regions of the protective layer structure have different optical properties. The lower layers (first and second protective layers) have high UV absorption capacity with weather resistant agents, while the upper layer (third protective layer) has high visible light transmittance. This local differentiation of properties allows simultaneous achievement of weather resistance and aesthetic appearance.
2Strength
If a substrate layer is used in decorative sheets, then structural support is provided, but the thickness affects design expression and luster of metal member
Solution Approach 1:
The invention extracts and removes the substrate layer from the decorative sheet structure, keeping only the essential functional layers (protective layers and pattern layer) that can be transferred to the metal member. This eliminates the thickness problem while maintaining the decorative function and allowing the metal member's luster to shine through the transparent portions.
Solution Approach 2:
Instead of using a thick substrate-based decorative sheet, the invention uses a thin transfer layer that copies only the necessary decorative elements (pattern layer) and protective functions onto the metal member surface. This copying approach maintains aesthetic quality while eliminating the substrate thickness issue.
3Illumination intensity
If the visible light transmittance is increased to leverage metal luster, then design expression is improved, but ultraviolet ray transmittance increases and weather resistance deteriorates
Solution Approach 1:
The protective function is segmented between different layers: the first and second protective layers handle UV protection with weather resistant agents, while the third protective layer handles visible light transmittance. This segmentation allows optimization of each layer for its specific function without compromise.
Solution Approach 2:
The protective layer structure uses composite material composition with different resin types and weather resistant agents in each layer. The first protective layer uses one type of resin with weather resistant agents, the second protective layer uses another resin composition, and the third protective layer uses a transparent resin formulation, creating a composite structure that achieves both UV protection and visible light transmittance.
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 transfer sheet enables the production of exterior members with high weather resistance and effective design expression by leveraging the luster of the metal member, while maintaining adequate adhesiveness and surface properties.
Implementation Method 1
the first protective layer and the second protective layer include a weather resistant agent; in the low covered area, an ultraviolet ray transmittance is 1% or less
Implementation Method 2
in the low covered area, an ultraviolet ray transmittance is 1% or less, and a visible light transmittance is 40% or more
Data Source
AI summary
A transfer sheet for producing an exterior member includes a metal member, the transfer sheet including: a releasing film, and a transfer layer disposed on one surface of the releasing film, wherein the transfer layer includes a first protective layer, a second protective layer, and a pattern layer, in this order from a releasing film side, in a thickness direction; the first protective layer and the second protective layer include a weather resistant agent; the transfer layer includes a low covered area with a hiding power ratio, measured according to JIS K 5600-4-1, of 50% or less; and in the low covered area, an ultraviolet ray transmittance is 1% or less, and a visible light transmittance is 40% or more.