Photocurable Ink Composition for Stretchable Coatings

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Solution Overview

Problem

Photocurable inkjet printing inks struggle to achieve satisfactory stretchability, heat resistance, and machinability, particularly when substrates undergo thermal molding or punching processing, as conventional monomers result in hard coatings that crack or delaminate under deformation and shear stress.

Innovation Solution

A photocurable inkjet printing ink composition with a monofunctional monomer content of 91.0 to 99.5% by mass, including acryloylmorpholine and specific monomers like benzyl acrylate or tetrahydrofurfuryl acrylate, combined with a multifunctional monomer content of 0.5 to 9.0% by mass, along with a photopolymerization initiator, to enhance stretching rate and prevent cracking during high-temperature processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional monofunctional monomers and multifunctional monomers are used to form cured coatings, then the coating hardness is improved, but the stretchability and adhesion are degraded

Engineering Contradiction:
Improvecoating hardnessVSAvoidstretchability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent applies parameter changes by precisely controlling the ratio of monofunctional to multifunctional monomers (91.0-99.5% and 0.5-9.0% by mass respectively) and selecting specific monomer types (acryloylmorpholine combined with benzyl acrylate, ethyl carbitol acrylate, or tetrahydrofurfuryl acrylate). This optimization achieves a balance where the coating maintains sufficient hardness while attaining a stretching rate of 120% or more at 180°C, resolving the contradiction between hardness and stretchability.

Inventive Principle:
Principle #35Parameter changes

2Strength

If conventional monofunctional monomers and multifunctional monomers are used to form cured coatings, then the coating hardness is improved, but the adhesion is degraded

Engineering Contradiction:
Improvecoating hardnessVSAvoidadhesion
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent optimizes the compositional parameters by limiting multifunctional monomer content to 0.5-9.0% by mass and incorporating specific monofunctional monomers with proven adhesion properties. This parameter optimization enables the cured coating to maintain both hardness and excellent adhesion, preventing delamination during punching and thermal molding processes while achieving a stretching rate of 120% or more at 180°C.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If cutting processing is used for thick plastic sheets, then the processing is possible, but the labor and time consumption increases

Engineering Contradiction:
Improveprocessing capabilityVSAvoidprocessing time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent changes the material parameters of the ink coating by optimizing monomer composition and ratios, resulting in a cured coating with enhanced machinability. The specific formulation (acryloylmorpholine 30.0-85.0% in monofunctional monomers combined with benzyl acrylate, ethyl carbitol acrylate, or tetrahydrofurfuryl acrylate at 5.0-40.0%) creates a coating that can be efficiently punched, dramatically reducing processing time and labor compared to cutting methods while maintaining processing capability for thick plastic sheets.

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 ink composition achieves a stretching rate of 120% or more at 180°C, maintaining heat resistance and preventing tackiness, enabling successful machine processing such as punching without cracking or delamination, even on substrates like polycarbonate.

Implementation Method 1

a photocurable inkjet printing ink composition comprising at least a photopolymerizable compound component, a photopolymerization initiator, and optionally a sensitizer

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP2749610B1Photocurable ink composition for inkjet printing, printed matter, and molded article
Publication Date: 2019.10.09 SAKATA INX
  • EP2749610B1 patent drawingFigure 1
  • EP2749610B1 patent drawing

AI summary

The present invention provides a photocurable inkjet printing ink composition including at least a photopolymerizable compound component and a photopolymerization initiator, wherein in the photopolymerizable compound component, a monofunctional monomer is included in a content of 91.0 to 99.5% by mass and a multifunctional monomer is included in a content of 0.5 to 9.0% by mass; in the monofunctional monomer component, acryloylmorpholine is included in a content of 30.0 to 85.0% by mass; the monofunctional monomer component includes at least one selected from benzyl acrylate, ethyl carbitol acrylate, tetrahydrofurfuryl acrylate and phenoxyethyl acrylate in a content of 5.0 to 40.0% by mass in the monofunctional monomer component; and the stretching rate at 180°C of the cured coating obtained by photopolymerizing the photocurable inkjet printing ink composition is 120% or more.