Decorative Sheet UV Absorber Bleed-Out Resolution
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Solution Overview
Problem
Decorative sheets with resin layers, such as polycarbonate resin, face challenges in suppressing time-dependent degradation caused by ultraviolet rays due to the bleed-out of ultraviolet absorbers, leading to reduced weather resistance and surface quality issues.
Innovation Solution
A decorative sheet comprising a base material layer, a transparent resin layer, and a surface protection layer, where at least one of the layers has a specific ultraviolet absorption wavelength range of 270 to 300 nm, with defined absorbance values (A11 and A12) to effectively absorb and manage ultraviolet radiation, thereby preventing degradation and enhancing weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultraviolet absorbers are added to surface protection layers to improve weather resistance, then weather resistance is improved, but the ultraviolet absorbers bleed out over time causing stickiness and reduced weather resistance
Solution Approach 1:
The patent introduces a specific ultraviolet absorber (benzotriazole compound with particular molecular structure) as an intermediary substance that mediates between the need for UV protection and the requirement for compositional stability. This specific compound acts as a bridge that provides effective UV absorption while maintaining long-term stability in the surface protection layer, preventing the bleed-out problem associated with conventional ultraviolet absorbers.
Solution Approach 2:
The patent changes the chemical parameters of the ultraviolet absorber by specifying a particular benzotriazole compound with defined molecular structure and properties. This parameter change transforms the ultraviolet absorber from a conventional substance prone to bleed-out into a stable compound that maintains its concentration over time, thereby resolving the contradiction between improving weather resistance and maintaining compositional stability.
2Reliability
If a surface protection layer with ultraviolet absorbers is applied to resin layers with absorption wavelengths at 270 to 300 nm, then UV absorption is enhanced, but the resin layers are degraded by the absorbed ultraviolet energy
Solution Approach 1:
The patent converts the harmful effect of ultraviolet energy absorption by the resin into a beneficial outcome by carefully selecting a benzotriazole compound that absorbs UV radiation in a manner that protects rather than degrades the resin. The specific ultraviolet absorber acts as a protective intermediary that transforms the potentially harmful UV energy into a protective effect, preventing resin degradation while maintaining absorption capability.
Solution Approach 2:
The specific benzotriazole compound serves as an intermediary between the ultraviolet radiation and the resin layer. It mediates the interaction by absorbing UV energy in a controlled manner that prevents the harmful effects on the resin while maintaining the necessary UV absorption capability, thus resolving the contradiction between enhanced UV absorption and resin integrity.
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 effectively suppresses time-dependent degradation and improves weather resistance by optimizing the absorbance values of the ultraviolet absorption wavelengths, balancing processing suitability and surface characteristics.
Implementation Method 1
absorbance A11 of the surface protection layer at wavelengths from 270 to 300 nm is 0.6 or more, and absorbance A12 of the transparent resin layer and the surface protection layer at wavelengths from 270 to 300 nm is 2.7 or more
Data Source
AI summary
Provided is a decorative sheet comprising a base material layer, a transparent resin layer and a surface protection layer in the presented order, wherein at least one of the base material layer and the transparent resin layer is constituted by a resin composition comprising a resin having an ultraviolet absorption wavelength at least at 270 to 300 nm; absorbance All of the surface protection layer at wavelengths from 270 to 300 nm is 0.6 or more; and absorbance A12 of the transparent resin layer and the surface protection layer at wavelengths from 270 to 300 nm is 2.7 or more, and wherein the decorative sheet can suppress time-dependent degradation caused by ultraviolet ray, and has excellent weather resistance. Also provided is a decorative material obtained using the decorative sheet.