Decorative Sheet With Dual Urethane Acrylates for Crack Resistance
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Solution Overview
Problem
Existing decorative sheets with ionizing radiation-curable resins suffer from curing shrinkage, contamination resistance, alkali resistance, and brittleness, leading to cracks and breakage, and the use of aliphatic isocyanate can destabilize these properties over time.
Innovation Solution
A decorative sheet with a laminate structure comprising a first surface-protecting layer made of two kinds of aliphatic urethane acrylates, one with an isocyanurate skeleton and the other with an alicyclic skeleton, and a second surface-protecting layer with lower hardness, providing a nanoindentation hardness range of 160-240 MPa and 100-240 MPa respectively, enhancing contamination and alkali resistance while reducing cracks and breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ionizing radiation-curable resin is used for the surface-protecting layer, then contamination resistance and alkali resistance are improved, but the layer becomes brittle and prone to cracks and breakage
Solution Approach 1:
The patent uses a composite resin system comprising both ionizing radiation-curable resin and two-component curable resin in the surface-protecting layer. This composite structure allows the layer to simultaneously achieve contamination resistance and alkali resistance from the ionizing radiation-curable resin while gaining impact resistance and flexibility from the two-component curable resin, thereby resolving the contradiction between durability and brittleness.
2Reliability
If an ionizing radiation-curable resin is used for the surface-protecting layer, then contamination resistance and alkali resistance are improved, but curing shrinkage occurs affecting surface quality
Solution Approach 1:
The patent combines ionizing radiation-curable resin with two-component curable resin in a composite system. The two-component curable resin compensates for the curing shrinkage of the ionizing radiation-curable resin, thereby maintaining surface quality and dimensional stability while preserving the contamination resistance and alkali resistance properties.
3Strength
If aliphatic isocyanate is added to the surface-protecting layer, then impact resistance is improved, but physical properties become unstable over time
Solution Approach 1:
The patent modifies the chemical composition parameters by replacing aliphatic isocyanate with aromatic isocyanate in the two-component curable resin system. This parameter change maintains the impact resistance benefits while improving long-term stability, as aromatic isocyanate provides more stable cured structures that resist degradation over time.
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 laminate structure with specific aliphatic urethane acrylates in the surface-protecting layers ensures long-term contamination and alkali resistance, minimizing cracks and breakage, and improves scratch resistance under high loads.
Implementation Method 1
a surface-protecting layer formed from an ionizing radiation-curable resin
Implementation Method 2
the first surface-protecting layer comprising an ionizing radiation-curable resin containing two kinds of aliphatic urethane acrylates
Data Source
Figure 1
Figure 2
Figure 3(a)~3(c)
AI summary
The present invention provides a decorative sheet comprising a surface-protecting layer, the surface-protecting layer having excellent contamination resistance, alkali resistance, etc., for a long period of time, while limiting the occurrence of breakage and cracks when an impact is applied thereto or during processing; and also provides a decorative plate using the decorative sheet. Specifically, the present invention provides a decorative sheet comprising a laminate, the laminate comprising at least a base material sheet and a first surface-protecting layer in sequence in the thickness direction; (1) the first surface-protecting layer comprising an ionizing radiation-curable resin containing two kinds of aliphatic urethane acrylates, i.e., resin A and resin B, wherein resin A is an aliphatic urethane acrylate with an isocyanurate skeleton, and resin B is an aliphatic urethane acrylate with an alicyclic skeleton without an isocyanurate skeleton, and (2) the first surface-protecting layer having a nanoindentation hardness of 160 MPa or more and 240 MPa or less. The present invention also provides a decorative plate using the decorative sheet.