Active Energy Ray Curable Ink with Polymeric Dispersant for Reliable Inkjet Discharge

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Solution Overview

Problem

High-viscosity pigment-based inks for inkjet systems face challenges in fluidity and discharge due to poor pigment dispersion, leading to aggregation and difficulty in initial discharge from inkjet heads without sufficient shearing stress.

Innovation Solution

An active energy ray curable composition comprising a polymerizable monomer, a polymer component, and a polymeric dispersant, with the polymeric dispersant content equal to or greater than its saturated adsorption amount to the pigment, ensuring improved dispersibility and fluidizability, and a yield value of 0.1 Pa or less, even upon drying to 70% of the initial weight, facilitating reliable inkjet discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high-viscosity pigment-based ink is used, then pigment durability is improved, but fluidity and dischargeability from inkjet head deteriorate

Engineering Contradiction:

Improvepigment durabilityVSAvoidfluidity and dischargeability

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent changes the chemical composition parameters of the ink by incorporating specific surfactants and solvents that modify the rheological properties. This allows the ink to maintain high pigment concentration for durability while achieving low yield value (0.1 Pa or less) for easy discharge, resolving the contradiction between strength and ease of operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite ink formulation combining pigment particles, surfactants, solvents, and resins in specific ratios. This composite structure allows the pigment to maintain durability while the surfactant-pigment complexes prevent aggregation and maintain fluidity, simultaneously achieving both durability and dischargeability.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If pigment dispersion is not uniform, then ink viscosity decreases, but pigment aggregation increases leading to poor discharge

Engineering Contradiction:

Improveink viscosityVSAvoiddischarge reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces surfactants as intermediary substances that mediate between pigment particles and the continuous phase. The surfactant adsorbs onto pigment surfaces, creating a steric or electrostatic barrier that prevents aggregation while maintaining uniform dispersion and low viscosity, ensuring reliable discharge without sacrificing manufacturability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes the concentration and type of surfactant to achieve the critical micelle concentration that maximizes dispersion stability. By controlling surfactant-to-pigment ratio and selecting specific surfactant molecules, the ink maintains low viscosity while preventing pigment aggregation, resolving the contradiction between ease of manufacture and discharge reliability.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If polymeric dispersant content is increased to improve dispersion, then dispersibility improves, but cost and viscosity may increase

Engineering Contradiction:

ImprovedispersibilityVSAvoidcomposition complexity and cost

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent optimizes the polymeric dispersant concentration to the minimum effective level that achieves saturated adsorption on pigment surfaces. This parameter optimization ensures maximum dispersibility while minimizing the amount of dispersant needed, thereby controlling cost and avoiding excessive viscosity increase from high dispersant loading.

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 ensures reliable inkjet discharge and adhesion to various substrates without surface treatment, maintaining safety by minimizing skin sensitization risks and providing sufficient curability, even when thickened by volatilization at nozzle surfaces.

Implementation Method 1

a polymeric dispersant, and a pigment, wherein the content of the polymeric dispersant is equal to or greater than a saturated adsorption amount of the polymeric dispersant to the pigment

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

an active energy ray curable composition includes a polymerizable monomer... emitting an active energy ray to the active energy ray curable composition to cause the active energy ray composition to cure

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS10227497B2Active energy ray curable composition, active energy ray curable ink, inkjet ink, stereoscopic modeling material, active energy ray curable composition container, two-dimensional or three dimensional image forming apparatus, two-dimensional or three-dimensional image forming method, cured product, and processed product

Publication Date: 2019.03.12 RICOH CO LTD

AI summary

An active energy ray curable composition is provided. The active energy ray curable composition includes a polymerizable monomer, a polymer component, a polymeric dispersant, and a pigment. The active energy ray curable composition is non-aqueous. The active energy ray curable composition has a yield value of 0.1 Pa or less either when having an initial weight or when being dried to have a weight 70% by mass of the initial weight.