Ink composition, inkjet recording method, printed material, process for producing lithographic printing plate, and lithographic printing plate
View Patent ↗An ink composition is provided that includes a cationically polymerizable compound (a), a compound (b) that generates an acid when exposed to radiation, a colorant (c), and a salt of a weak acid having a pKa of 4 to 8 (d). There is also provided an inkjet recording method that includes a step of discharging the ink composition onto a recording medium, and a step of irradiating the discharged ink composition with radiation so as to cure the ink composition.
1. An ink composition comprising:
(a) a cationically polymerizable compound;
(b) a compound that generates an acid when exposed to radiation;
(c) a colorant; and
(d) a salt of a weak acid having a pKa of 4 to 8.
2. The ink composition according to claim 1 , wherein the salt of the weak acid having a pKa of 4 to 8 is an ammonium salt.
3. The ink composition according to claim 1 , wherein the colorant is a pigment or an oil-soluble dye.
4. The ink composition according to claim 3 , wherein the oil-soluble dye has an oxidation potential of 1.0 V (vs SCE) or greater.
5. The ink composition according to claim 1 , wherein it is for inkjet recording.
6. The ink composition according to claim 1 , wherein the salt of the weak acid having a pKa of 4 to 8 is a salt of an aromatic carboxylic acid.
7. The ink composition according to claim 1 , wherein it is for inkjet recording.
8. An inkjet recording method comprising:
a step (a) of discharging an ink composition onto a recording medium; and
a step (b) of irradiating the discharged ink composition with actinic radiation so as to cure the ink composition,
the ink composition being the ink composition according to claim 1 .
9. The inkjet recording method according to claim 8 , wherein the actinic radiation is ultraviolet radiation emitted by a light emitting diode that has a light emission peak wavelength in the range of 350 to 420 nm and generates ultraviolet radiation whose maximum illumination intensity on the surface of a recording medium is 10 to 2,000 mW/cm 2 .
10. A printed material recorded by the inkjet recording method according to claim 9 .
11. A process for producing a lithographic printing plate, the process comprising:
a step (a) of discharging the ink composition according to claim 1 onto a hydrophilic support; and
a step (b) of irradiating the discharged ink composition with actinic radiation so as to cure the ink composition, thus forming a hydrophobic image on the hydrophilic support by curing the ink composition.
12. A lithographic printing plate produced by the lithographic printing plate production process according to claim 11 .