Radiation-Curable Epoxyacrylate Coatings for Solvent-Free Curing

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Solution Overview

Problem

Existing radiation-curable water-based coating compositions often contain high levels of organic solvents and rely on chemical crosslinking reactions, which are not suitable for applications requiring solvent-free and radiation-induced curing processes, especially for coating various substrates like wood, plastics, and metal.

Innovation Solution

The development of radiation-curable water-based coating compositions involving the reaction of self-dispersing epoxy resins with acrylic and/or methacrylic acid to form epoxyacrylates, where more than 50% of epoxide groups are ring-opened, allowing for radiation-induced curing without the need for organic solvents and using these epoxyacrylates in aqueous dispersions for coating applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If existing radiation-curable water-based coating compositions are used, then radiation-induced curing is achieved, but high levels of organic solvents are present

Engineering Contradiction:
Improveorganic solvent contentVSAvoidhandling and application behavior
Core Design Contradiction:
Object-generated harmful factorsVSEase of operation

Solution Approach 1:

The patent changes the chemical composition parameters by introducing epoxyacrylates with specific molecular structures (combining epoxy groups for crosslinking and acrylate groups for radiation curing) and controlling their content (5-50% by weight), thereby achieving solvent-free formulations while maintaining curability and application properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating system combining epoxy resins (for crosslinking and adhesion), acrylates (for radiation-induced polymerization), and water (as solvent), forming a multi-component system that achieves both environmental benefits and functional performance

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If chemical crosslinking reactions are used, then coating formation is achieved, but radiation-induced curing processes cannot be implemented

Engineering Contradiction:
Improvecuring method compatibilityVSAvoidcrosslinking reaction suitability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent makes the coating composition universally curable by incorporating epoxy groups (for chemical crosslinking with hardeners) and acrylate groups (for radiation-induced polymerization) into the same molecular structure, allowing the same base composition to be cured by multiple different mechanisms depending on application requirements

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent segments the crosslinking function into two separate reactive components within the epoxyacrylate molecule: epoxy groups dedicated to chemical crosslinking and acrylate groups dedicated to radiation-induced curing, allowing independent optimization of each curing pathway

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If self-dispersing epoxy resins are used with polyol (meth)acrylic acid esters, then aqueous dispersions are formed, but complex chemical crosslinking reactions occur instead of radiation-induced curing

Engineering Contradiction:
Improveaqueous dispersion formationVSAvoidcomplex chemical crosslinking
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

Instead of using separate epoxy resins and polyol acrylates that require chemical hardeners, the patent inverts the approach by directly synthesizing epoxyacrylates where the epoxy and acrylate functionalities are combined in the same molecule, eliminating the need for separate hardener addition and enabling direct radiation-induced curing

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent merges the epoxy resin component and the acrylate component into a single epoxyacrylate molecule, combining the adhesion benefits of epoxy with the radiation curability of acrylates, thereby simplifying the formulation and enabling radiation-induced curing without complex chemical crosslinking

Inventive Principle:
Principle #5Merging (Combining)

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 resulting compositions exhibit excellent handling and application behavior, providing high gloss, chemical resistance, and scratch resistance, particularly suitable for wood coatings with excellent adhesion and suitable for a variety of substrates including metal and plastics.

Implementation Method 1

the reaction between components (A) and (B) is conducted in such a way that the epoxide groups present in component (A) are predominantly ring-opened by the carboxyl functions present in component (B)

Methodology Applied
Scientific EffectRing-opening reaction: Chemical Bonding

Implementation Method 2

radiation-curable water-based coating compositions

Methodology Applied
Scientific EffectRadiation-induced curing: Photopolymerisation

Data Source

PatentUS8524808B2Radiation curable compositions
Publication Date: 2013.09.03 IGM GROUP

AI summary

The invention is a radiation curable coating composition containing epoxyacrylate formed by ring opening reaction between (meth)acrylic acid and a self-dispersing epoxy resin in an aqueous system.