WATER-BASED INK FOR INKJET RECORDING

Abstract

A water-based ink for inkjet recording contains a pigment, water, organic solvents, at least one compound selected from urea compounds, and a binder resin. The organic solvents include at least (1) a water-soluble organic solvent having a boiling point of from 100° C. to 200° C. inclusive and a vapor pressure at 20° C. of 0.5 hPa or more, (2) propylene glycol, and (3) glycerin, diglycerin, and/or a derivative thereof serving as an organic solvent. Preferably, the water-based ink further contains a polymer (A) serving as a pigment dispersant. The polymer (A) has an anionic group and has a solubility in water of 0.1 g/100 mL or more, a number average molecular weight within the range of 1,000 to 6,000, and an acid value within the range of 40 to 190 mg KOH/g.

Claims

1. A water-based ink for inkjet recording, comprising a pigment, water, organic solvents, at least one compound selected from urea compounds, and a binder resin, wherein the organic solvents include at least: (1) a water-soluble organic solvent having a boiling point of from 100° C. to 200° C. inclusive and a vapor pressure at 20° C. of 0.5 hPa or more, (2) propylene glycol, and (3) glycerin, diglycerin, and/or a derivative thereof serving as an organic solvent.

2. The water-based ink for inkjet recording according to claim 1, further comprising a polymer (A) serving as a pigment dispersant, the polymer (A) having an anionic group and having a solubility in water of 0.1 g/100 mL or less, a number average molecular weight within the range of 1,000 to 6,000, and an acid value within the range of 40 to 190 mg KOH/g.

3. The water-based ink for inkjet recording according to claim 1, further comprising a polymer (A) represented by general formula (1) as a pigment dispersant, the polymer (A) having an anionic group and having a solubility in water of 0.1 g/100 mL or less, a number average molecular weight within the range of 1,000 to 6,000, and an acid value within the range of 40 to 190 mg KOH/g: ##STR00003## (wherein, in formula (1), A.sup.1 represents an organic lithium initiator residue, A.sup.2 represents a polymer block of a monomer having an aromatic ring or a heterocycle, A.sup.3 is a polymer block containing an anionic group, n represents an integer of 1 to 5, and B represents an aromatic group or an alkyl group).

4. The water-based ink for inkjet recording according to claim 1, further comprising an acetylene-based surfactant.

5. The water-based ink for inkjet recording according to claim 1, wherein the water-soluble organic solvent having a boiling point of from 100° C. to 200° C. inclusive and a vapor pressure at 20° C. of 0.5 hPa or more is 3-methoxy-1-butanol or 3-methyl-3-methoxy-1-butanol.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0288] FIG. 1 is a schematic diagram of the microreactor used in the present invention.

REFERENCE SIGNS LIST

[0289] 1: T-shaped micromixer M1 [0290] 2: T-shaped micromixer M2 [0291] 3: T-shaped micromixer M3 [0292] 4: tube reactor R1 [0293] 5: tube reactor R2 [0294] 6: tube reactor R3 [0295] 7: tube reactor P1 for precooling [0296] 8: tube reactor P2 for precooling [0297] 9: tube reactor P3 for precooling [0298] 10: tube reactor P4 for precooling