Curable Composition Inkjet Coating Storage Stability

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Solution Overview

Problem

Curable compositions containing cationic polymerizable substances and photocationic initiators tend to thicken upon long-term storage, lacking good storage stability and effective film formation abilities, particularly in inkjet coating applications.

Innovation Solution

A curable composition comprising a polyfunctional vinyl ether compound, a polyfunctional thiol compound, a curing agent with both photoradical initiator and photoacid generator, a carbazole-based photosensitizing agent, and an imidazole stabilizing agent, which together ensure effective curing and film formation through inkjet coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a curable composition containing a cationic polymerizable substance and a photocationic initiator is used, then good curability and film formation ability are achieved, but the composition thickens upon long-term storage

Engineering Contradiction:
ImprovecurabilityVSAvoidstorage stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The curing system is segmented into two independent parts: a photoradical initiator system for radical polymerization and a photoacid generator system for cationic polymerization. This segmentation allows each system to function independently, preventing the unwanted interaction that causes thickening while maintaining both curability and storage stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite curing system combining photoradical initiators (for vinyl group polymerization) and photoacid generators (for cationic polymerization of cyclic ether groups). This composite approach enables dual-mechanism curing that achieves complete crosslinking without the side reactions that cause viscosity increase during storage.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If a curable composition containing a cationic polymerizable substance and a photocationic initiator is used, then effective film formation is achieved, but storage stability deteriorates

Engineering Contradiction:
Improvefilm formation abilityVSAvoidstorage stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The invention changes the chemical parameters of the curing system by introducing specific photoradical initiators (α-hydroxy ketone, α-aminophenyl ketone, or acylphosphine oxide compounds) that work synergistically with photoacid generators. This parameter change enables the system to maintain film formation ability while preventing storage-induced thickening through controlled dual-polymerization mechanisms.

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 stable viscosity over time, maintaining excellent inkjet coatability and UV curability, resulting in well-cured films with improved storage stability and mechanical properties.

Implementation Method 1

a curing agent (C), a photosensitizing agent (D)... the curing agent (C) including a photoradical initiator (C1) and a photoacid generator (C2)... exposing the coated film

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

the photosensitizing agent (D) including a carbazole compound... exposing the coated film

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 3

a stabilizing agent (E)... the stabilizing agent (E) being an imidazole compound... stable viscosity over time, maintaining excellent inkjet coatability... improved storage stability

Methodology Applied
Scientific EffectStabilization:

Data Source

PatentUS20240034899A1Curable composition
Publication Date: 2024.02.01 TOKYO OHKA KOGYO CO LTD

AI summary

Provided are a curable composition curing well and having a good film formation ability with an inkjet coating, a cured product of the curable composition, and a method for forming a cured film using the curable composition. The curable composition contains a polyfunctional vinyl ether compound (A), a polyfunctional thiol compound (B), a curing agent (C), a photosensitizing agent (D), and stabilizing agent (E). In the curable composition, a photoradical initiator (C1) and a photoacid generator (C2) are used as the curing agent (C), a carbazole compound is used as the photosensitizing agent (D), and an imidazole compound is used as the stabilizing agent (E).