Water-based inkjet yellow ink, ink set, and method for producing printed matter
View Patent ↗One embodiment relates to a water-based inkjet yellow ink containing a yellow pigment (A) having a specific partial structure, an organic solvent, a basic organic compound, and water, wherein an amount of the yellow pigment (A) is 1 to 10% by mass of a total mass of the water-based inkjet yellow ink, the basic organic compound contains 0.1 to 1.25% by mass of a basic organic compound (B) having a pKa value of 9.5 or less at 25° C. of the total mass of the water-based inkjet yellow ink, and an amount of an organic solvent having a boiling point of 240° C. or higher under 1 atmosphere is 5% by mass or less of the total mass of the water-based inkjet yellow ink.
1. A water-based inkjet yellow ink comprising:
a yellow pigment (A) having a partial structure represented by general formula (1), an organic solvent, a basic organic compound, a binder resin, and water, wherein
an amount of the yellow pigment (A) is 1 to 10% by mass of a total mass of the water-based inkjet yellow ink;
the basic organic compound contains 0.1 to 1.25% by mass of a basic organic compound (B) having a pKa value of 9.5 or less at 25° C. of the total mass of the water-based inkjet yellow ink,
an amount of an organic solvent having a boiling point of 240° C. or higher under 1 atmosphere is 5% by mass or less of the total mass of the water-based inkjet yellow ink, and
the binder resin includes olefin resin microparticles, and
if an amine value of the yellow pigment (A) is Am (PA) [mgKOH/g], the amount of the yellow pigment (A) of the total mass of the water-based inkjet yellow ink is C (PA) [% by mass], an acid value of the olefin resin microparticles is Av (RO) [mgKOH/g], and an amount of the olefin resin microparticles of the total mass of the water-based inkjet yellow ink is C (RO) [% by mass], the acid value/amine value ratio represented by formula (8) shown below is 0.5×10 −4 to 15×10 −4 ,
wherein, general formula (1) has at least one bonding site, and
in general formula (1),
X 1 and X 2 represent both ═O or both ═CR 6 R 7 , or X 1 is ═O and X 2 is ═NR 8 ,
each R 1 to R 4 independently represents a hydrogen atom or a halogen atom,
R 5 represents a hydrogen atom or a bonding site,
each R 6 to R 8 represents a bonding site, and
Acid value/amine value ratio={Av(RO)×C(RO)}÷{Am(PA)×C(PA)} formula (8).
2. The water-based inkjet yellow ink according to claim 1 , wherein
an amount of the basic organic compound (B) having a pKa value of 9.5 or less at 25° C. is 0.1 to 1% by mass of the total mass of the water-based inkjet yellow ink.
3. The water-based inkjet yellow ink according to claim 1 , wherein
the yellow pigment (A) includes C. I. Pigment Yellow 139 and/or C. I. Pigment Yellow 185.
4. The water-based inkjet yellow ink according to claim 1 , wherein
an amount of impurities contained in the yellow pigment (A) is 5% by mass or less of a total mass of the yellow pigment (A).
5. A inkjet ink set comprising:
the water-based inkjet yellow ink according to claim 1 , and
a water-based inkjet magenta ink containing magenta pigment and water.