Aqueous Inkjet Ink with Siloxane-Coated Polymer

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Solution Overview

Problem

Aqueous inkjet inks with low-polarity solvents face issues with encapsulating resins dissolving, leading to thickening or gelling, which affects dispersion stability and nozzle blockage.

Innovation Solution

An aqueous ink formulation featuring a polymer compound with a β-diketone group, cationic salt-forming group, and a cross-linked siloxane linkage, which acts as a pigment dispersant and coating resin, preventing dissolution in various solvents and maintaining ink fluidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If an encapsulating resin is used to improve pigment dispersion stability in aqueous ink, then dispersion stability is improved, but the resin may dissolve in low-polarity solvents causing thickening or gelling

Engineering Contradiction:
Improvedispersion stabilityVSAvoidink fluidity
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent uses a composite polymer compound containing both hydrophobic groups (for pigment binding and low-polarity solvent resistance) and hydrophilic groups (for water solubility and dispersion stability). This composite structure prevents resin dissolution in low-polarity solvents while maintaining dispersion stability, resolving the contradiction between improved_feature and worsening_feature.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If a water-soluble organic solvent is used in aqueous ink, then ink fluidity is improved, but the solvent may cause encapsulating resin to dissolve leading to thickening or gelling

Engineering Contradiction:
Improveink fluidityVSAvoiddispersion stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent modifies the chemical structure parameters of the polymer compound by incorporating specific functional groups (β-diketone groups for metal coordination, cationic salt-forming groups for electrostatic stabilization) that change the resin's interaction properties with solvents. This prevents dissolution in water-soluble organic solvents while maintaining ink fluidity, resolving the contradiction between improved_feature and worsening_feature.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If pigment is dispersed in aqueous medium without encapsulation, then ink simplicity is maintained, but dispersion stability is poor leading to nozzle blockage

Engineering Contradiction:
Improveink formulation simplicityVSAvoidnozzle blockage resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a polymer compound as an intermediary between the pigment and aqueous medium. This intermediary provides both dispersion stability and nozzle blockage resistance through its dual functionality of pigment binding and electrostatic stabilization, while keeping the ink formulation relatively simple. The polymer acts as a mediator that prevents direct pigment aggregation and nozzle blockage.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 exhibits improved storage stability, pigment dispersibility, and discharge characteristics, with reduced risk of nozzle blockage, allowing for immediate reactivation after moisture evaporation.

Implementation Method 1

the polymer compound has a β-diketone group and a cationic salt-forming group, and also includes a cross-linked structure based on a siloxane linkage

Methodology Applied
Scientific EffectCross-linking:

Implementation Method 2

a cross-linked structure based on a siloxane linkage

Methodology Applied
Scientific EffectSiloxane linkage:

Implementation Method 3

the polymer compound has a β-diketone group and a cationic salt-forming group

Methodology Applied
Scientific EffectCoordination complex formation:

Implementation Method 4

the polymer compound has a β-diketone group and a cationic salt-forming group

Methodology Applied
Scientific EffectElectrostatic interaction:

Data Source

PatentUS8546465B2Aqueous ink for inkjet
Publication Date: 2013.10.01 RISO KAGAKU CORP

AI summary

An aqueous ink for an inkjet, comprising a pigment, a polymer compound that coats the pigment, a water-soluble organic solvent, and water, whereinthe polymer compound has a β-diketone group and a cationic salt-forming group, and also includes a cross-linked structure based on a siloxane linkage.