Printed Object Ink Receiving Layer Monomer Dissipation

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Solution Overview

Problem

Conventional printing methods using actinic radiation-curable ink on ink-receiving layers face issues with unreacted monomers remaining in the layer, leading to odor and poor adhesion, and existing solutions either fail to reduce monomer dissipation effectively or compromise film properties like weather resistance.

Innovation Solution

A printed matter is developed with an ink-receiving layer having an ink absorption rate of 100% or less, using a polymerizable compound with a glass transition temperature of -45° C to 25° C, and a monomer dissipation rate of 10.0 μg/m2/hr or less, combined with a surface protecting layer to minimize monomer dissipation and enhance adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If conventional coating materials for receiving layers are used, then the receiving layer can be formed, but unreacted monomers remain in the layer causing odor and poor adhesion

Engineering Contradiction:
Improvemonomer dissipation and odorVSAvoidadhesion between ink and receiving layer
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent changes the glass transition temperature parameter of the polymerizable compound from conventional high values to specifically -45°C to 25°C. This parameter change enables the receiving layer to maintain proper adhesion while reducing monomer dissipation, as the lower Tg allows for better molecular mobility and bonding without excessive monomer retention.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system combining the receiving layer with specific polymerizable compounds (having Tg of -45°C to 25°C) and actinic radiation-curable ink. This composite approach allows the receiving layer to provide both good adhesion and reduced monomer dissipation simultaneously, resolving the contradiction between these two properties.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If printing is performed on an absorbent substrate or ink-receiving layer, then the receiving layer can accept the ink, but monomers remain in the receiving layer in uncured state and are dissipated

Engineering Contradiction:
Improveink application on receiving layerVSAvoidmonomer dissipation
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the glass transition temperature parameter of the polymerizable compound in the receiving layer to -45°C to 25°C. This parameter optimization allows the receiving layer to maintain its ink-receiving functionality while significantly reducing monomer dissipation after curing, as the controlled Tg prevents excessive monomer mobility and dissipation.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If a dense receiving layer is formed to prevent monomer permeation, then monomer dissipation is reduced, but adhesion force due to anchoring effect cannot be obtained

Engineering Contradiction:
Improvemonomer dissipationVSAvoidadhesion force
Core Design Contradiction:
Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent optimizes the glass transition temperature parameter to a specific range (-45°C to 25°C) that balances two opposing requirements: it provides sufficient molecular mobility for strong adhesion through anchoring effects, while simultaneously limiting monomer permeation and dissipation. This precise parameter control resolves the contradiction between adhesion strength and monomer retention.

Inventive Principle:
Principle #35Parameter changes

4Object-generated harmful factors

If excessive amount of photopolymerization initiator is used to reduce unreacted monomers, then monomer dissipation is reduced, but film properties such as weather resistance or chromogenic property are deteriorated

Engineering Contradiction:
Improveunreacted monomerVSAvoidfilm property
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent changes the approach from controlling photopolymerization initiator amount to controlling the glass transition temperature of the polymerizable compound itself. By optimizing the Tg parameter to -45°C to 25°C, the system achieves complete monomer reaction without requiring excessive initiator, thereby preserving film properties like weather resistance and chromogenic properties while eliminating unreacted monomers.

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 solution effectively reduces unreacted monomer dissipation and improves adhesion between the ink and receiving layer, while maintaining excellent chromogenic properties and film characteristics like weather resistance.

Implementation Method 1

an ink layer comprising an actinic radiation-curable ink containing a polymerizable compound

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11820165B2Printed object
Publication Date: 2023.11.21 DAI NIPPON TORYO CO LTD

AI summary

Disclosed is a printed object which, even if using a receptive layer that is difficult for a monomer in an active energy ray curable ink to penetrate, has excellent adhesion between the active energy ray curable ink and the receptive layer, and in which the amount of unreacted monomer dissipated from the printed object is low. This printed object includes an ink receptive layer laminated on a substrate surface and having an ink absorption rate of 100% or less, and an ink layer laminated on a surface of the ink receptive layer and made from an active energy ray curable ink which includes a polymerizable compound, wherein the glass transition temperature of the polymerizable compound is −45-25° C.