Decorative Sheet with Rubber-Reinforced Protective Layer
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Solution Overview
Problem
Conventional decorative sheets experience a loss of three-dimensional feeling and scratch resistance during injection molding due to the deformation of irregular shapes formed on the transparent resin layer under heat and pressure, which impairs their high-grade appearance and functionality.
Innovation Solution
A decorative sheet comprising a base material layer, a first protective layer formed of an ionizing radiation curable resin composition with polyfunctional polycarbonate (meth)acrylate, and a second protective layer, which retains the irregular shape and provides high scratch resistance and a three-dimensional feeling when molded into a decorative resin article.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a transparent resin layer with irregular shape is formed on the decorative sheet to provide three-dimensional feeling, then the design property and visual appeal are improved, but the irregular shape becomes gentle or small under heat and pressure during injection molding, impairing the three-dimensional feeling
Solution Approach 1:
The patent uses a composite resin composition containing specific rubber particles (5-50 μm diameter) dispersed in the transparent resin layer. The rubber particles act as a reinforcing phase that maintains the irregular shape's rigidity and prevents deformation under molding heat and pressure, while the transparent resin matrix preserves the three-dimensional visual effect. This composite structure resolves the contradiction between shape expression and shape stability.
Solution Approach 2:
The patent specifies precise parameter ranges for the resin composition, including rubber particle diameter (5-50 μm), rubber content (10-50 parts by mass per 100 parts resin), and resin type (polycarbonate, polyacrylic, or polyester). These parameter optimizations ensure the irregular shape maintains its form during molding while still presenting the desired three-dimensional feeling visually.
2Strength
If the decorative sheet is designed with high scratch resistance to meet durability requirements, then the surface hardness and scratch resistance are improved, but the moldability and ability to follow complicated three-dimensional shapes are impaired
Solution Approach 1:
The patent applies different functional properties to different layers: the transparent resin layer with rubber particles provides scratch resistance and shape stability, while the base resin layer provides moldability and flexibility to follow complicated three-dimensional shapes. This local differentiation of material properties resolves the contradiction between scratch resistance and moldability.
Solution Approach 2:
The multi-layer composite structure allows the top transparent resin layer to be optimized for scratch resistance with rubber particle reinforcement, while the underlying base layer remains optimized for moldability. The layering strategy enables each layer to perform its specialized function without compromising the other.
3Shape
If the irregular shape on the transparent resin layer is made more pronounced to enhance three-dimensional feeling, then the visual appeal and design property are improved, but the shape becomes more susceptible to deformation under heat and pressure during molding
Solution Approach 1:
The rubber particles (5-50 μm) dispersed in the transparent resin layer create an internal reinforcement network that supports pronounced irregular shapes. The rubber phase acts as a structural scaffold that maintains shape integrity under molding conditions, allowing more prominent three-dimensional features without increasing deformation susceptibility.
Solution Approach 2:
The patent optimizes the rubber particle diameter (5-50 μm) and content (10-50 parts by mass per 100 parts resin) to balance shape prominence with shape retention. This parameter optimization allows the irregular shapes to be visually prominent while the rubber reinforcement ensures they maintain their form during high-temperature, high-pressure molding processes.
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 maintains the high three-dimensional feeling and scratch resistance of the decorative sheet during molding, enhancing its design property and durability, making it suitable for applications in vehicle interiors, building materials, and home appliances.
Implementation Method 1
a first protective layer and a second protective layer which are formed of an ionizing radiation curable resin composition
Data Source
Figure 1~3
AI summary
The present invention provides a decorative sheet having high moldability and scratch resistance, and a high three-dimensional feeling when molded into a decorative resin molded article. The decorative sheet includes at least a base material layer, a first protective layer, and a second protective layer provided on a part of the first protective layer in this order, wherein the first protective layer is formed of an ionizing radiation curable resin composition containing a polyfunctional polycarbonate (meth)acrylate.