Photopolymerizable Inkjet Ink Reducing Skin Sensitization

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Solution Overview

Problem

Conventional photopolymerizable inkjet inks face issues with skin sensitization, high viscosity, and environmental concerns due to the use of toxic monomers and solvents, which affect the strength and appearance of cured coating films, and require energy-intensive drying processes.

Innovation Solution

A non-aqueous photopolymerizable composition comprising diethylene glycol dimethacrylate, a polymerization initiator, and a polyether-modified polysiloxane compound, which reduces skin sensitization risks, achieves low viscosity, and enhances coating film strength and appearance, while being environmentally friendly and energy-efficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional (meth)acrylic acid esters are used as monomers, then low cost and availability are achieved, but skin sensitization and toxicity increase

Engineering Contradiction:
Improveavailability and costVSAvoidskin sensitization
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical structure parameters of the monomer by selecting specific (meth)acrylic acid esters with particular molecular characteristics (such as ethyl methacrylate, butyl methacrylate, hexyl methacrylate) that have lower skin sensitization potential while maintaining the essential polymerization properties needed for ink functionality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining multiple components including the selected low-sensitization monomer, polymerization initiator, and optional additives to achieve both safety and performance requirements simultaneously

Inventive Principle:
Principle #40Composite materials

2Force

If water is blended to reduce viscosity, then inkjet ejection is improved, but penetration and drying on non-absorbent bases fail

Engineering Contradiction:
ImproveviscosityVSAvoidpenetration and drying
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent changes the viscosity parameter through molecular design by selecting monomers with appropriate chain lengths and structures (such as longer alkyl chains in butyl, hexyl methacrylates) that inherently provide lower viscosity while maintaining non-aqueous composition for reliable performance on various substrates

Inventive Principle:
Principle #35Parameter changes

3Force

If organic solvent is used to reduce viscosity, then inkjet ejection is improved, but environmental pollution and energy consumption increase

Engineering Contradiction:
ImproveviscosityVSAvoidenvironmental pollution
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the organic solvent component from the ink formulation, replacing it with a non-aqueous monomer system that achieves appropriate viscosity through molecular structure selection rather than solvent addition, thereby eliminating environmental pollution and energy-intensive drying

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the viscosity parameter through monomer molecular structure design rather than through solvent composition, selecting monomers with appropriate chain lengths and structures that provide inherent low viscosity without requiring volatile organic solvents

Inventive Principle:
Principle #35Parameter changes

4Strength

If polymerization reactivity is increased to improve coating film strength, then durability is improved, but skin sensitization risk increases

Engineering Contradiction:
Improvecoating film strengthVSAvoidskin sensitization
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical structure parameters of the monomer by selecting specific (meth)acrylic acid esters with particular molecular characteristics that balance polymerization reactivity for adequate film strength while having lower skin sensitization potential, such as monomers with specific alkyl chain lengths and structures

Inventive Principle:
Principle #35Parameter changes

5Shape

If high glossiness is achieved by forming uniform surface, then appearance is improved, but scratch resistance decreases

Engineering Contradiction:
Improvesurface uniformityVSAvoidscratch resistance
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent creates a composite formulation combining the selected low-sensitization monomer with polymerization initiator and optional additives that work synergistically to achieve both surface uniformity for high glossiness and adequate crosslinking for scratch resistance

Inventive Principle:
Principle #40Composite materials

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 provides a safe, low-viscosity ink with improved coating film strength and appearance, eliminating skin sensitization concerns and reducing environmental impact, and allows for efficient curing without the need for energy-intensive drying processes.

Implementation Method 1

photopolymerizable composition, photopolymerizable inkjet ink

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP2904020B1Photopolymerizable composition, photopolymerizable inkjet ink, and ink cartridge
Publication Date: 2017.12.06 RICOH CO LTD
  • EP2904020B1 patent drawingFigure 1~2
  • EP2904020B1 patent drawing

AI summary

To provide a non-aqueous photopolymerizable composition, which contains: a polymerizable monomer; a polymerization initiator; and a polyether-modified polysiloxane compound represented by the following general formula (1): <General Formula (1)> (CH3)3Si-O-[Si(CH3)2-O]a-[Si(CH3)(X)-O]b-Si(CH3)3 where X represents R(C2H4O)c(C3H6O)d-R', R is a single bond or an alkylene group, R' is a hydrogen atom or an alkyl group, and a to d each denote an average polymerization degree including a case where either c or d is 0.