Hard-coat Composition for Metal Substrate with Hybrid Curing

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Solution Overview

Problem

Existing hard coating materials for metal base materials face challenges with adhesion, particularly in water-resistant adhesion, and productivity, as they either require long curing times or have inferior adhesion to metal surfaces.

Innovation Solution

A hard coat coating composition combining urethane (meth)acrylate with a carboxyl group, urethane (meth)acrylate without a carboxyl group, a thermoplastic resin with a carboxyl group, and a silane coupling agent, which can be cured with an active energy beam, enhancing initial and water-resistant adhesion while maintaining favorable productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heat-curable coating materials are used, then adhesion to metal base material is improved, but curing time increases reducing productivity

Engineering Contradiction:
Improveadhesion to metal base materialVSAvoidcuring time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines heat-curable components (polyester polyol, polyisocyanate) with active energy beam-curable components ((meth)acrylate compounds, photopolymerization initiator) into a single hybrid coating composition. This merging allows the coating to achieve both good adhesion from the heat-curable portion and fast curing from the active energy beam-curable portion, resolving the contradiction between adhesion and productivity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coating composition uses a composite system containing multiple types of resins and curing agents that can cure through both thermal and photopolymerization mechanisms. The polyester polyol and polyisocyanate provide adhesion properties, while the (meth)acrylate compounds enable rapid active energy beam curing, creating a composite material that satisfies both requirements

Inventive Principle:
Principle #40Composite materials

2Productivity

If active energy beam-curable coating materials are used, then productivity is improved with fast curing, but adhesion to metal base material deteriorates

Engineering Contradiction:
Improvecuring timeVSAvoidadhesion to metal base material
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent merges active energy beam-curable components ((meth)acrylate compounds for fast curing) with heat-curable components (polyester polyol and polyisocyanate known for adhesion). This combination allows the coating to cure rapidly under active energy beam while the heat-curable portion ensures good adhesion to metal substrates, resolving the contradiction between productivity and adhesion

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If conventional hard coating materials are used, then scratch resistance is achieved, but water-resistant adhesion deteriorates

Engineering Contradiction:
Improvescratch resistanceVSAvoidwater-resistant adhesion
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the coating by incorporating polyester polyol with specific hydroxyl value and polyisocyanate components that enhance both hardness and water resistance. The specific ratio and selection of these components allow the coating to maintain scratch resistance while improving water-resistant adhesion through enhanced crosslinking and polarity

Inventive Principle:
Principle #35Parameter changes

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 composition achieves superior adhesion to metal base materials, both initially and under water resistance tests, with improved productivity, making it suitable for applications on metals like aluminum, iron, or chrome.

Implementation Method 1

active energy beam-curable component (A) including a (meth)acrylate compound and a photopolymerization initiator

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

a silane coupling agent (D)

Methodology Applied
Scientific EffectSilane coupling: Chemical Bonding

Data Source

PatentEP2677009B1Hard-coat composition for metal substrate, and molded article
Publication Date: 2016.09.14 FUJIKURA KASEI CO LTD

AI summary

A hard coat coating composition for a metal base material, includes a coated film forming component including a urethane (meth)acrylate (A) having a carboxyl group and having a solid fraction acid value being value of 0.5 to 2.0 mgKOH/g, a urethane (meth)acrylate (B) not having a carboxyl group, a thermoplastic resin (C) having a carboxyl group and having a solid fraction acid value of 1.0 to 30 mgKOH/g, and a silane coupling agent (D).