Monomer Mixture for Oxygen-Resistant Cationic Curing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Cationically curable compositions used in inkjet recording methods face issues with adhesion to metals and glass, and the cured products have low hardness and unsatisfactory dimensional stability, requiring surface processing treatments.

Innovation Solution

A monomer mixture containing specific cationically polymerizable monomers, such as those with vinyl ether, epoxy, and oxetanyl groups, along with a curing catalyst, is used to achieve rapid curing and high adhesion to metals and glass, even in the presence of oxygen, resulting in a cured product with high hardness and low curing shrinkage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If cationically curable composition is used to achieve rapid curing and good adhesion, then curing speed and adhesion are improved, but adhesion to metals and glass remains low and surface processing is required

Engineering Contradiction:

Improvecuring speedVSAvoidadhesion to metals and glass

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent changes the chemical parameters of the monomer mixture by incorporating specific compounds (Formula I and Formula II) with particular functional groups and structural characteristics. This modifies the curing composition's chemical reactivity and bonding properties, enabling direct adhesion to metals and glass without surface treatment while maintaining rapid curing speed.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite monomer system combining multiple cationically polymerizable monomers with different functional groups (vinyl ether, epoxy, oxetanyl) and specific molecular structures. This composite approach synergistically improves both adhesion to difficult substrates like metals and glass, and curing performance, while eliminating the need for primer treatments.

Inventive Principle:

Principle #40Composite materials

2Reliability

If cationically curable composition is used, then curing is not inhibited by oxygen, but the cured product has low hardness and unsatisfactory dimensional stability

Engineering Contradiction:

Improvecuring in presence of oxygenVSAvoidhardness and dimensional stability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent modifies the chemical composition parameters by incorporating monomers with specific structural features (Formula I and Formula II) that promote highly crosslinked network formation. This changes the physical properties of the cured product, achieving high hardness and excellent dimensional stability while maintaining the ability to cure in the presence of oxygen through the cationic polymerization mechanism.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If inkjet recording uses low viscosity ink for dischargeability, then dischargeability is improved, but oxygen diffusion into ink increases causing curing inhibition

Engineering Contradiction:

ImprovedischargeabilityVSAvoidoxygen diffusion and curing inhibition

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of oxygen diffusion into a beneficial outcome by using cationic polymerization chemistry that is inherently insensitive to oxygen inhibition. The low-viscosity ink formulation enables excellent dischargeability, while the cationic curing mechanism ensures complete polymerization even with high oxygen exposure during jetting and drying, transforming the previously problematic oxygen interaction into a non-issue.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 curable composition exhibits excellent adhesion and dimensional stability, allowing direct application to metal and glass surfaces without pre-treatment, forming a high-hardness, accurate ink coating film with reduced curing shrinkage and odor generation.

Implementation Method 1

Upon irradiation with ultraviolet light, the monomer mixture can be rapidly cured even in the presence of oxygen

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3611206B1Monomer mixture and curable composition containing same

Publication Date: 2024.02.21 DAICEL CORP

Figure 1

AI summary

The present invention is to provide a monomer mixture that is cured rapidly even in the presence of oxygen and that forms a cured product having high hardness and excellent adhesion to metals and/or glass. The monomer mixture according to an embodiment of the present invention contains two or more types of cationically polymerizable monomers. As the cationically polymerizable monomers, the monomer mixture contains at least 10 wt.%, based on a total amount of the monomer mixture, of a compound having at least one cationically polymerizable group selected from the group consisting of a vinyl ether group, an epoxy group, and an oxetanyl group, and at least one hydroxy group in a molecule, and at least 5 wt.%, based on the total amount of the monomer mixture, of a compound represented by Formula (b). In the formula, R represents an s-valent straight-chain or branched saturated aliphatic hydrocarbon group or an s-valent group having two or more straight-chain or branched saturated aliphatic hydrocarbon groups bonded to each other through an ether bond, and s represents an integer of 2 or greater.