Decorative Sheet Surface Protective Layer Erosion Control
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Solution Overview
Problem
Decorative sheets made from olefin-based resins face challenges in scratch resistance, particularly under high load conditions, as existing methods to enhance scratch resistance, such as increasing the hardness and thickness of surface protective layers or adding inorganic fillers, can lead to brittleness, poor impact resistance, and increased costs.
Innovation Solution
A decorative sheet configuration featuring a primary film, a transparent resin layer, and a surface protective layer with specific erosion rates, where the surface protective layer is formed of multiple layers with ionizing radiation-curable and thermosetting resins, and the transparent resin layer has a controlled erosion rate, optimizing scratch resistance without compromising impact resistance or weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hardness and thickness of the surface protective layer are increased to improve scratch resistance, then scratch resistance is improved, but impact resistance and weather resistance deteriorate due to brittleness
Solution Approach 1:
The surface protective layer is divided into multiple layers: a first surface protective layer with higher hardness (ionizing radiation-curable resin, erosion rate 0.10-0.45 μm/g) and a second surface protective layer with lower hardness (thermosetting resin, erosion rate 0.30-0.60 μm/g). This segmentation allows the outer layer to provide scratch resistance while the inner layer provides toughness and flexibility, preventing brittleness and maintaining impact and weather resistance.
Solution Approach 2:
Different regions of the surface protective layer have different properties: the outer first layer has high hardness for scratch resistance, while the inner second layer has lower hardness for flexibility. This local differentiation of material properties resolves the contradiction between scratch resistance and impact resistance.
2Strength
If the hardness and thickness of the transparent resin layer are increased to improve scratch resistance, then scratch resistance is improved, but impact resistance and weather resistance deteriorate due to brittleness
Solution Approach 1:
The erosion rate of the transparent resin layer is precisely controlled within 0.05-2.0 μm/g, optimizing the balance between scratch resistance and flexibility. This parameter control allows the transparent resin layer to provide scratch resistance without becoming excessively hard and brittle, thereby maintaining impact and weather resistance.
3Strength
If inorganic filler is added to the surface protective layer to improve scratch resistance, then scratch resistance is improved, but the inorganic filler may protrude, break, or detach causing gloss change and potential damage
Solution Approach 1:
The patent removes inorganic filler from the surface protective layer composition entirely, replacing it with an organic resin-based system (ionizing radiation-curable resin and thermosetting resin). This extraction eliminates the problems of inorganic filler protrusion, breaking, and detachment that cause gloss change and surface damage.
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 proposed configuration provides enhanced scratch resistance under high load conditions while maintaining impact resistance and weather resistance, balancing performance and cost effectively.
Implementation Method 1
an ionizing radiation-curable resin is applied to a surface protective layer and cured
Implementation Method 2
the erosion rate E being measured by using polygonal alumina particles having an average particle size (D50) of 1.2 μm
Data Source
AI summary
A decorative sheet includes a primary film layer; a transparent resin layer; and a surface protective layer, in this order; the surface protective layer is formed of a plurality of layers with a layer located on an outermost surface is a surface protective layer, and a layer underlying the surface protective layer is a second surface protective layer and includes one or more ionizing radiation-curable resins having an erosion rate E in a range of 0.10 μm/g or more and 0.45 μm/g or less, and one or more thermosetting resins having an erosion rate E in a range of 0.30 μm/g or more and 0.6 μm/g or less, the erosion rate E being measured by using polygonal alumina powder having an average particle size (D50) of 1.2 μm, and a mass ratio between the ionizing radiation-curable resin and the thermosetting resin (ionizing radiation-curable resin/thermosetting resin) is 95/5 to 40/60.