Water-based inkjet ink and method for producing inkjet printed material
View Patent ↗An embodiment relates to an inkjet ink containing a mixed crystal pigment including two or more naphthol-based azo pigments, a binder resin (a-1) having an acid value of 1 to 80 mgKOH/g, a surfactant, and a water-soluble organic solvent, in which the amount of a water-soluble organic solvent having a boiling point of 240° C. or more at 1 atmosphere is 8% by mass or less relative to the total amount of the water-based inkjet ink.
1. A water-based inkjet ink comprising a colorant, a binder resin (A), a surfactant, and a water-soluble organic solvent, wherein
the colorant includes a mixed crystal pigment containing two or more naphthol-based azo pigments,
the binder resin (A) includes a binder resin (a-1) having an acid value of 1 to 80 mgKOH/g,
the binder resin (a-1) includes a polyolefin resin, and at least one type of resin selected from the group consisting of a (meth)acrylic resin and a styrene-(meth)acrylic resin, and
an amount of a water-soluble organic solvent having a boiling point of 240° C. or more at 1 atmosphere is 8% by mass or less relative to a total amount of the water-based inkjet ink.
2. The water-based inkjet ink according to claim 1 , wherein the water-soluble organic solvent includes an alkanediol of 2 to 5 carbon atoms.
3. The water-based inkjet ink according to claim 1 , wherein a total amount of a nitrogen-containing compound having a pKa value of 2 or less at 25° C. and a nitrogen-containing compound having a pKa value of 10 or more at 25° C. is 3% by mass or less relative to a total amount of the water-based inkjet ink.
4. The water-based inkjet ink according to claim 1 , wherein the two or more naphthol-based azo pigments include a compound having a structure represented by general formula (1) shown below,
General formula (1):
wherein, in general formula (1), R 1 , R 2 , and R 3 are each independently any one of a hydrogen atom, an alkyl group of 1 to 2 carbon atoms, an alkoxy group of 1 to 2 carbon atoms, an anilide group, a carbamoyl group, a methoxycarbonyl group, an ethoxycarbonyl group, an amino group, a nitro group, a sulfonamide group, a methylaminosulfonyl group, or an ethylaminosulfonyl group, and
R 4 is any one of a hydrogen atom, an alkyl group of 1 to 2 carbon atoms, or a group having a structure represented by general formula (2) shown below,
General formula (2):
wherein, in general formula (2), R 5 is any one of a hydrogen atom, a chlorine atom, a bromine atom, an alkyl group of 1 to 2 carbon atoms, an alkoxy group of 1 to 2 carbon atoms, an amino group, or a nitro group,
R 6 and R 7 are each independently any one of a hydrogen atom, a chlorine atom, a bromine atom, an alkyl group of 1 to 2 carbon atoms, an alkoxy group of 1 to 2 carbon atoms, an amino group, or a nitro group, or R 6 and R 7 are bonded to each other to form an imidazolidinone ring, and
a position of * is a bonding site.
5. The water-based inkjet ink according to claim 1 , wherein the two or more naphthol-based azo pigments include a compound having a structure represented by general formula (3) shown below,
General formula (3):
wherein, in general formula (3), R 4 is any one of a hydrogen atom, an alkyl group of 1 to 2 carbon atoms, or a group having a structure represented by general formula (2) shown below,
General formula (2):
wherein, in general formula (2), R 5 is any one of a hydrogen atom, a chlorine atom, a bromine atom, an alkyl group of 1 to 2 carbon atoms, an alkoxy group of 1 to 2 carbon atoms, an amino group, or a nitro group,
R 6 and R 7 are each independently any one of a hydrogen atom, a chlorine atom, a bromine atom, an alkyl group of 1 to 2 carbon atoms, an alkoxy group of 1 to 2 carbon atoms, an amino group, or a nitro group, or R 6 and R 7 are bonded to each other to form an imidazolidinone ring, and
a position of * is a bonding site.
6. The water-based inkjet ink according to claim 1 , wherein the two or more naphthol-based azo pigments include C.I. Pigment Red 150.
7. The water-based inkjet ink according to claim 1 , wherein the two or more naphthol-based azo pigments include 10 to 80% by mole of C.I. Pigment Red 150 in a total amount of the naphthol-based pigments.
8. A method for producing an inkjet printed material comprising discharging and applying the water-based inkjet ink according to claim 1 from an inkjet head onto a recording medium.
9. A water-based inkjet ink comprising a colorant, a binder resin (A), a surfactant, and a water-soluble organic solvent, wherein
the colorant includes a mixed crystal pigment containing two or more naphthol-based azo pigments,
the two or more naphthol-based azo pigments include 10 to 80% by mole of C.I. Pigment Red 150 in a total amount of the naphthol-based pigments,
the binder resin (A) includes a binder resin (a-1) having an acid value of 1 to 80 mgKOH/g, and
an amount of a water-soluble organic solvent having a boiling point of 240° C. or more at 1 atmosphere is 8% by mass or less relative to a total amount of the water-based inkjet ink.
10. The water-based inkjet ink according to claim 9 , wherein the binder resin (a-1) includes at least one type of resin selected from the group consisting of a (meth)acrylic resin, a styrene-(meth)acrylic resin, a urethane resin, a urethane-(meth)acrylic composite resin, and a polyolefin resin.