Aqueous resin based inkjet inks
An inkjet ink includes a) an aqueous medium; and b) capsules composed of a polymeric shell surrounding a core; wherein the capsules are dispersed in the aqueous medium using a dispersing group covalently bonded to the polymeric shell; wherein the core contains a photoinitiator and one or more chemical reactants capable of forming a reaction product upon application of UV light; wherein the capsules have an average particle size of no more than 4 μm as determined by dynamic laser diffraction; and wherein the photoinitiator is a diffusion hindered photoinitiator selected from the group consisting of multifunctional photoinitiators, oligomeric photoinitiators, polymeric photoinitiators and polymerizable photoinitiators.
1. A method of manufacturing an aqueous inkjet ink including capsules including a cross-linked polymeric shell surrounding a core containing at least one chemical reactant that forms a reaction product upon application of UV light, the method comprising the steps of:
preparing the capsules using interfacial polymerization of an oleophilic phase in an aqueous continuous phase, the aqueous continuous phase including a first shell component and the oleophilic phase including a second shell component; and
adding at least one of water, a humectant, and a surfactant; wherein
the aqueous inkjet ink includes at least one photoinitiator.
2. The manufacturing method according to claim 1 , wherein the capsules are prepared from di- or oligoalcohols as the first shell component and di- or oligoisocyanates as the second shell component.
3. The manufacturing method according to claim 2 , wherein the capsules are dispersed in an aqueous medium using a dispersing group covalently bonded to the cross-linked polymeric shell.
4. The manufacturing method according to claim 3 , wherein the dispersing group is selected from the group consisting of a carboxylic acid or salt thereof, a sulfonic acid or salt thereof, a phosphoric acid ester or salt thereof, a phosphonic acid or salt thereof, an ammonium group, a sulfonium group, a phosphonium group, and a polyethylene oxide group.
5. The manufacturing method according to claim 1 , wherein the cross-linked polymeric shell is prepared from di- or oligoamines as the first shell component and di- or oligoisocyanates as the second shell component.
6. The manufacturing method according to claim 1 , wherein the capsules are dispersed in an aqueous medium with a polymeric dispersant.
7. The manufacturing method according to claim 1 , wherein the aqueous inkjet ink includes polymeric latex particles.
8. The manufacturing method according to claim 1 , wherein the at least one photoinitiator is selected from the group consisting of benzophenone, a substituted benzophenone, 1-hydroxycyclohexyl phenyl ketone, a thioxanthone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-benzyl-2-dimethylamino-(4-morpholinophenyl) butan-1-one, benzil dimethylketal, bis (2,6-dimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-methyl-1-[4-(methylthio) phenyl]-2-morpholinopropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, and 5,7-diiodo-3-butoxy-6-fluorone.
9. The manufacturing method according to claim 1 , wherein the humectant is selected from the group consisting of triacetin, N-methyl-2-pyrrolidone, glycerol, urea, thiourea, alkyl urea, alkyl thiourea, dialkyl urea, dialkyl thiourea, diols, glycols and mixtures thereof.
10. The manufacturing method according to claim 1 , wherein the at least one chemical reactant that forms a reaction product upon the application of UV light includes a polyfunctional acrylate monomer or oligomer.
11. The manufacturing method according to claim 1 , wherein the aqueous inkjet ink contains a colorant.
12. The manufacturing method according to claim 11 , wherein the colorant is a white pigment.
13. An aqueous inkjet ink obtained by the manufacturing method according to claim 1 .
14. An inkjet ink set comprising:
a plurality of the aqueous inkjet ink according to claim 13 ; wherein
the plurality of the aqueous inkjet inks include a cyan inkjet ink, a magenta inkjet ink, a yellow inkjet ink, and a black inkjet ink.
15. An ink set comprising:
an aqueous UV curable inkjet ink including:
at least one photoinitiator;
capsules including a cross-linked polymeric shell surrounding a core containing at least one UV curable compound;
a dispersing group covalently bonded to the cross-linked polymeric shell and selected from the group consisting of a carboxylic acid or salt thereof, a sulfonic acid or salt thereof, a phosphoric acid ester or salt thereof, and a phosphonic acid or salt thereof; and
a liquid including a cationic substance.
16. The ink set according to claim 15 , wherein the cationic substance includes polymeric cations or multivalent cations.
17. The ink set according to claim 15 , wherein the dispersing group is a carboxylic acid or salt thereof.
18. The ink set according to claim 15 , wherein the aqueous UV curable inkjet ink includes a white pigment.
19. The ink set according to claim 18 , wherein the white pigment has a refractive index greater than 1.60.
20. The ink set according to claim 19 , wherein the aqueous UV curable inkjet ink includes a cyan inkjet ink, a magenta inkjet ink, a yellow inkjet ink, and a black inkjet ink.
21. The ink set according to claim 15 , wherein the at least one photoinitiator is selected from the group consisting of benzophenone, a substituted benzophenone, 1-hydroxycyclohexyl phenyl ketone, a thioxanthone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-benzyl-2-dimethylamino-(4-morpholinophenyl) butan-1-one, benzil dimethylketal, bis (2,6-dimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-methyl-1-[4-(methylthio) phenyl]-2-morpholinopropan-1-one, 2,2-dimethoxy-1,2-diphenylethan-1-one, and 5,7-diiodo-3-butoxy-6-fluorone.
22. The ink set according to claim 21 , wherein the at least one photoinitiator includes a photoinitiator selected from the group consisting of multifunctional photoinitiators, oligomeric photoinitiators, polymerizable photoinitiators, and polymeric photoinitiators.
23. The ink set according to claim 21 , wherein the photoinitiator is present in the core of the capsules.
24. The ink set according to claim 15 , wherein the at least one UV curable compound in the core of the capsules includes a polyfunctional acrylate monomer or oligomer.
25. The ink set according to claim 15 , wherein the aqueous UV curable inkjet ink includes an optothermal converting agent.
26. The ink set according to claim 15 , wherein the cross-linked polymeric shell includes a material selected from the group consisting of polyureas, polyurethanes, polyesters, polycarbonates, polyamides, melamine based polymers and mixtures thereof.
27. An inkjet printing method comprising the steps of:
jetting an aqueous UV curable inkjet ink from the ink set according to claim 15 onto a substrate;
applying the liquid including the cationic substance; and
applying UV radiation to the aqueous UV curable inkjet ink jetted on the substrate.
28. The inkjet printing method according to claim 27 , wherein the UV radiation is emitted by UV LEDs.