Aqueous inkjet-printing ink

A water-based ink with specific organic solvents and surfactants addresses poor wetting and spreading on low-absorbency substrates, improving image quality by stabilizing ejection and reducing white spots.

WO2026029070A1PCT designated stage Publication Date: 2026-02-05KAO CORP
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Patent Information

Application Number
PCT/JP2025/026893
Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
Priority Date
2025-07-28
Filing Date
2025-07-29
Publication Date
2026-02-05

AI Technical Summary

Technical Problem

Inkjet printing on low-absorbency substrates, such as resin films, faces issues with poor wetting and spreading properties, leading to reduced image quality due to poor filling of solid images and intermittent ejection stability, along with the occurrence of white spots from insufficient surfactant dissolution.

Method used

A water-based ink comprising specific organic solvents and surfactants with defined boiling points and octanol-water partition coefficients, along with a pigment and water, enhances wetting and spreading on low-absorbency substrates, improving intermittent ejection stability and suppressing white spots.

Benefits of technology

The ink achieves excellent wetting and spreading on low-absorbency substrates, maintains stable ejection performance, and reduces white spots, thereby enhancing image quality.

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Abstract

One aspect of the present invention is an aqueous inkjet-printing ink for a poorly-absorbent printing base material. The ink contains a pigment, an organic solvent (A), an organic solvent (B), a surfactant, and water. The organic solvent (A) has a boiling point of not less than 140°C to less than 200°C, and an octanol-water partition coefficient logP of 0.10-1.20. The organic solvent (B) has a boiling point of 200-260°C, and an octanol-water partition coefficient logP of 0.10-0.70. The HLB value of the surfactant is 1.0-8.0. The mass ratio (A) / (B) of the organic solvent (A) and the organic solvent (B) is preferably 0.5-3.0.
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Citation Information

Patent Citations

  • Water-based ink

    JP2016210959A

  • Aqueous ink

    JP2017226834A

  • Water based ink for inkjet recording

    JP2022102163A

  • Water-based white ink for ink-jet recording

    JP2022148275A

  • Water-based inkjet inks and printed matter

    JP7536986B1