Dual-Layer Active Energy Ray-Curable Coating for Adhesion and Scratch Resistance

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Solution Overview

Problem

Existing active energy ray-curable compositions face challenges in maintaining adhesiveness and scratch resistance, especially when exposed to severe conditions such as hot water and alkaline solutions, leading to potential peeling off from the base.

Innovation Solution

An image forming method involving two active energy ray-curable compositions: Composition A with a polymerizable monomer having a phosphoric ester group and a polyester resin for adhesiveness, and Composition B with a multifunctional polymerizable compound for scratch resistance, applied and cured in a specific sequence to enhance durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single active energy ray-curable composition is used, then the curing process is simple, but the scratch resistance and adhesiveness under severe conditions are insufficient

Engineering Contradiction:
Improvescratch resistance and adhesiveness under severe conditionsVSAvoidcuring process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention divides the coating system into two separate compositions: Composition A (applied first, containing adhesion promoters) and Composition B (applied second, containing scratch resistance agents). This segmentation allows each composition to specialize in providing specific properties, with Composition A ensuring strong base adhesiveness and Composition B providing scratch resistance, thereby resolving the technical contradiction between reliability and process complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite coating structure by laminating two different active energy ray-curable compositions. Composition A forms the base layer with excellent adhesiveness to the substrate, while Composition B forms the top layer with high scratch resistance. This composite material approach allows the final cured object to simultaneously achieve both strong adhesion and scratch resistance under severe conditions.

Inventive Principle:
Principle #40Composite materials

2Reliability

If Composition A with phosphoric ester group is used, then adhesiveness to base is improved, but scratch resistance may be compromised

Engineering Contradiction:
Improveadhesiveness to baseVSAvoidscratch resistance
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention separates the functions of adhesion and scratch resistance into two distinct compositions. Composition A contains phosphoric ester groups that provide excellent adhesiveness to the base, while Composition B contains components that provide scratch resistance. By applying Composition B over the cured Composition A, both properties are achieved without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite coating where Composition A (with phosphoric ester groups for adhesion) forms the bottom layer bonded to the base, and Composition B (with scratch resistance properties) forms the top layer. This composite structure allows the phosphoric ester groups in Composition A to maximize adhesiveness while Composition B provides the necessary scratch resistance, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

3Strength

If Composition B with multifunctional polymerizable compound is used, then scratch resistance is improved, but adhesiveness to base may be reduced

Engineering Contradiction:
Improvescratch resistanceVSAvoidadhesiveness to base
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention divides the functional requirements into two compositions: Composition A (applied first) contains components optimized for base adhesiveness, and Composition B (applied second) contains components optimized for scratch resistance. This segmentation ensures that Composition B's scratch resistance components do not interfere with base adhesion, as Composition A already establishes the adhesive bond to the base.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite coating structure where Composition A forms the adhesive base layer bonded to the substrate, and Composition B forms the protective top layer providing scratch resistance. The multifunctional polymerizable compounds in Composition B provide excellent scratch resistance in the top layer without compromising the adhesiveness established by Composition A at the base interface.

Inventive Principle:
Principle #40Composite materials

4Reliability

If dual composition application is used, then scratch resistance and adhesiveness are both improved, but the number of steps increases

Engineering Contradiction:
Improvedurability under severe conditionsVSAvoidapplication efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention segments the coating into two compositions that can be applied in sequence. While this adds a step, each composition is optimized for specific properties, and both can be cured by active energy rays. The segmentation allows for specialized formulation of each layer to achieve maximum durability under severe conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite material approach with two active energy ray-curable compositions. Composition A is applied and cured first, then Composition B is applied and cured. This composite structure provides superior durability under severe conditions including hot water and alkaline solutions, with the dual-layer system ensuring both adhesiveness and scratch resistance are maintained.

Inventive Principle:
Principle #40Composite materials

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 method achieves excellent scratch resistance and adhesiveness even after exposure to extreme conditions, preventing peeling and maintaining integrity on the base.

Implementation Method 1

an active energy ray-curable composition is cured by irradiation with an active energy ray

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP4198097B1Image forming method and active energy ray-curable composition set
Publication Date: 2024.05.29 RICOH CO LTD
  • EP4198097B1 patent drawingFigure 1~2

AI summary

An image forming method is provided that includes: applying, on a base, an active energy ray-curable composition A containing a polymerizable monomer having a phosphoric ester group and a polyester resin; curing the active energy ray-curable composition A; applying, on a cured object of the active energy ray-curable composition A, an active energy ray-curable composition B containing a multifunctional polymerizable compound having two or more polymerizable functional groups in its molecule; and curing the active energy ray-curable composition B.