Crosslinked Decorative Sheet Coating for Hardness and Adhesion

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Solution Overview

Problem

Existing decorative sheets lack sufficient adhesion to lower layers, surface hardness, scratch resistance, and processability, particularly when used on wood or plastic boards.

Innovation Solution

A decorative sheet with a surface-protecting layer containing a crosslinked curable resin, characterized by specific peak height ratios in infrared spectroscopic measurements, ensuring excellent adhesion, hardness, and processability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a hard-coat layer is added to improve surface hardness and scratch resistance, then surface protection is improved, but adhesion to the lower layer becomes insufficient

Engineering Contradiction:
Improvesurface hardnessVSAvoidadhesion
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies different functional characteristics to different regions of the coating system. The surface-protecting layer contains crosslinked curable resin for hardness, while the lower layer contains reactive groups for adhesion. This local differentiation of material properties resolves the contradiction between surface protection and bonding strength.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses a composite coating structure where the surface-protecting layer is composed of crosslinked curable resin and the lower layer contains reactive groups. This composite material approach allows simultaneous achievement of surface hardness and adhesion by combining materials with complementary properties.

Inventive Principle:
Principle #40Composite materials

2Strength

If the surface-protecting layer is made harder to improve scratch resistance, then surface durability is improved, but processability deteriorates

Engineering Contradiction:
Improvescratch resistanceVSAvoidprocessability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent incorporates reactive groups in the lower layer before the curing process. These reactive groups are prepared in advance to ensure proper adhesion and processability during manufacturing, while the crosslinked curable resin provides the required hardness after curing. This preliminary preparation resolves the contradiction between durability and manufacturability.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If adhesion promoters are added to improve bonding to films with few polar groups, then adhesion is improved, but surface hardness may be reduced

Engineering Contradiction:
Improveadhesion to filmVSAvoidsurface hardness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent places adhesion-promoting reactive groups specifically in the lower layer that contacts the film, while maintaining crosslinked curable resin in the surface-protecting layer for hardness. This spatial separation of functions resolves the contradiction between adhesion promotion and surface hardness maintenance.

Inventive Principle:
Principle #3Local quality

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 decorative sheet achieves enhanced adhesion to lower layers, improved surface hardness, and better scratch resistance, making it suitable for various applications such as building materials and furniture.

Implementation Method 1

the surface-protecting layer containing a crosslinked curable resin

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

the decorative sheet having a peak height ratio of A to B ((A/B)×100 (%)) of 105% or more and 400% or less, with A representing the height of a peak appearing at 855 to 1325 cm -1

Methodology Applied
Scientific EffectInfrared spectroscopy: Absorption Spectroscopy

Data Source

PatentEP4691763A1Decorative sheet and decorative board
Publication Date: 2026.02.11 DAI NIPPON PRINTING CO LTD
  • EP4691763A1 patent drawingFigure 1A~1C
  • EP4691763A1 patent drawingFigure 2
  • EP4691763A1 patent drawingFigure 3

AI summary

The present invention provides a decorative sheet having a surface-protecting layer that has excellent adhesion to the lower layer, and having excellent surface hardness and scratch resistance, as well as excellent processability. The present invention provides a decorative sheet having at least a surface-protecting layer, the surface-protecting layer containing a crosslinked curable resin, and the decorative sheet having a peak height ratio of A to B ((A/B)×100 (%)) of 105% or more and 400% or less, with A representing the height of a peak appearing at 855 to 1325 cm-1 and B representing the height of a peak appearing at 1650 to 1800 cm-1, in infrared spectroscopic measurement of the surface-protecting layer, and a peak height ratio of B to C ((B/C)×100 (%)) of 1000% or more and 6000% or less, with C representing the height of a peak appearing at 3200 to 3500 cm-1, in infrared spectroscopic measurement of the surface-protecting layer.