Phase change ink compositions
View Patent ↗A phase change ink composition comprising (a) at least one curable monomer or prepolymer, (b) at least one gellant, (c) at least one hyperbranched polymer comprising at least one photoinitiating moiety, (d) a colorant, (e) optionally, a reactive oligomer; and (f) optionally, at least one low molecular weight photo initiator.
1. A phase change ink composition comprising:
(a) at least one curable monomer or prepolymer, (b) at least one gellant, wherein the gellant is a mixture of
wherein —C 34 H 56+a — represents a branched alkylene group, which may or may not include unsaturations and cyclic groups, substituted and unsubstituted alkylene groups, and wherein heteroatoms either may or may not be present in the alkylene group, wherein a is an integer of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, (c) at least one hyperbranched polymer comprising at least one photoinitiating moiety, (d) a colorant (e) optionally, a reactive oligomer; and (f) optionally, at least one low molecular weight photoinitiator.
2. The phase change ink composition of claim 1 , wherein the colorant comprises a pigment.
3. The phase change ink composition of claim 1 , wherein the colorant is present in the ink composition in an amount of at least about 0.1 percent by weight of the ink composition to no more than about 8 percent by weight of the ink composition.
4. The phase change ink composition of claim 1 , further comprising a wax containing at least one acrylate.
5. The phase change ink composition of claim 1 , wherein the at least one curable monomer is propoxylated neopentyl glycol diacrylate, isobornyl acrylate, isobornyl methacrylate, lauryl acrylate, lauryl methacrylate, isodecylacrylate, isodecylmethacrylate, caprolactone acrylate, 2-phenoxyethyl acrylate, isooctylacrylate, isooctylmethacrylate, butyl acrylate, or mixtures and combinations thereof.
6. The phase change ink composition of claim 1 , wherein the at least one curable monomer or prepolymer is a multifunctional acrylate or methacrylate compound.
7. The phase change ink composition of claim 6 , wherein the multifunctional acrylate or methacrylate compound is propoxylated neopentyl glycol diacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, 1,2-ethylene glycol diacrylate, 1,2-ethylene glycol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, 1,12-dodecanol diacrylate, 1,12-dodecanol dimethacrylate, tris(2-hydroxy ethyl) isocyanurate triacrylate, hexanediol diacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, amine modified polyether acrylate, trimethylolpropane triacrylate, glycerol propoxylate triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaerythritol tetraacrylate, or mixtures or combinations thereof.
8. The phase change ink composition of claim 1 , wherein the at least one hyperbranched polymer comprises at least one initiating functional group, at least one co-initiating functional group and at least one compatibilizing group.
9. The phase change ink composition of claim 1 , wherein the at least one hyperbranched polymer is a compound of the formula
wherein R is a hyperbranched polyglycidol or a dendritic polymer polyol.
10. The phase change ink composition of claim 1 , wherein the at least one hyperbranched polymer is a compound of the formula
wherein R is a hyperbranched polyglycidol.
11. The phase change ink composition of claim 1 , wherein the at least one hyperbranched polymer is present in an amount of from about 1 to about 25 percent by weight based upon the weight of the ink composition.
12. The phase change ink composition of claim 1 , wherein the optional reactive oligomer comprises acrylated polyesters, acrylated polyethers, acrylated epoxies, urethane acrylates, pentaerythritol tetraacrylate, or a mixture or combination thereof.
13. The phase change ink composition of claim 1 , wherein the optional reactive oligomer is present in an amount of from about 0.5 to about 10 percent by weight based upon the weight of the ink composition.
14. The phase change ink composition of claim 1 , wherein the optional at least one low molecular weight photoinitiator is selected from the group consisting of benzyl ketones, monomeric hydroxyl ketones, α-amino ketones, acyl phosphine oxides, metallocenes, benzophenone, benzophenone derivatives, isopropyl thioxanthenones, arylsulphonium salts and aryl iodonium salts.
15. The phase change ink composition of claim 1 , wherein the optional at least one low molecular weight photoinitiator is present in an amount of from about 0.5 to about 5 percent by weight based upon the weight of the ink composition.
16. A process which comprises (I) incorporating into an ink jet printing apparatus a phase change ink composition comprising (a) at least one curable monomer or prepolymer, (b) at least one gellant, wherein the gellant is a mixture of
wherein —C 34 H 56+a — represents a branched alkylene group, which may or may not include unsaturations and cyclic groups, substituted and unsubstituted alkylene groups, and wherein heteroatoms either may or may not be present in the alkylene group, wherein a is an integer of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12, (c) at least one hyperbranched polymer comprising at least one photoinitiating moiety, (d) a colorant (e) optionally, a reactive oligomer; and (f) optionally, at least one low molecular weight photoinitiator; (II) melting the ink; (III) causing droplets of the melted ink to be ejected in an imagewise pattern onto a substrate; and (IV) exposing the imagewise pattern to ultraviolet radiation.
17. A process according to claim 16 wherein the substrate is a final recording sheet and droplets of the melted ink are ejected in an imagewise pattern directly onto the final recording sheet and the imagewise pattern on the final recording sheet is exposed to ultraviolet radiation.
18. A process according to claim 16 wherein the substrate is an intermediate transfer member and droplets of the melted ink are ejected in an imagewise pattern onto the intermediate transfer member followed by transfer of the imagewise pattern from the intermediate transfer member to a final recording sheet, and wherein the imagewise pattern on the final recording sheet is exposed to ultraviolet radiation.
19. A process according to claim 18 wherein the intermediate transfer member is heated to a temperature above that of the final recording sheet and below that of the melted ink in the printing apparatus.