Aqueous inkjet ink production method and image formation method

The method stabilizes aqueous inkjet inks by using specific HSP value solvents during phase inversion emulsification and solvent evaporation, addressing thickening and aggregation issues, and enhancing jetting stability and abrasion resistance.

WO2026014191A1PCT designated stage Publication Date: 2026-01-15KONICA MINOLTA INC
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Patent Information

Application Number
PCT/JP2025/022156
Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
Priority Date
2024-07-10
Filing Date
2025-06-19
Publication Date
2026-01-15

AI Technical Summary

Technical Problem

Aqueous inkjet inks using resin emulsions suffer from thickening and aggregation due to the use of diethylene glycol monobutyl ether (DEGBE) as a water-soluble solvent, leading to instability and decreased abrasion resistance, especially at high temperatures.

Method used

A method involving phase inversion emulsification with a first water-soluble solvent having a specific HSP value range, followed by distilling off the solvent, is used to produce a resin water dispersion, combined with a second water-soluble solvent to stabilize the ink, ensuring a difference in HSP values between the two solvents is within a certain threshold.

Benefits of technology

The method stabilizes the ink's jetting performance over time, improves jetting stability after standby, enhances abrasion resistance, and maintains image quality by preventing resin particle aggregation and drying issues.

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Abstract

In the present invention, the difference between a weighted average HSP value (A) of a first water-soluble solvent and a weighted average HSP value (B) of a second water-soluble solvent is within a specific range. The present invention comprises steps (a), (d), and (e), and comprises either step (b) or step (c).　Step (a) is for dissolving a resin in an organic solvent to produce a resin solution. Step (b) is for adding water and the first water-soluble solvent to the resin solution to produce a resin emulsion. Step (c) is for adding water to the resin solution to produce a resin emulsion, and then adding the first water-soluble solvent to the resin emulsion. Step (d) is for removing the organic solvent, by distillation, from the resin emulsion to which the first water-soluble solvent has been added, to produce an aqueous resin dispersion. Step (e) is for mixing the aqueous resin dispersion, a color material, and the second water-soluble solvent together to produce ink.
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Citation Information

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