Non-aqueous pigment dispersions using dispersion synergists
View Patent ↗Non-aqueous pigment dispersions exhibit improved dispersion quality and/or stability for a specific selection of quinacridone pigments, diketopyrrolo-pyrrole pigments and azo pigments by using specific naphthol AS dispersion synergists. The non-aqueous pigment dispersions can be advantageously used in inkjet inks inkjet printing methods.
1. A non-aqueous pigment dispersion comprising:
a non-aqueous dispersion medium, a polymeric dispersant, a pigment, and a dispersion synergist; wherein
the dispersion synergist is represented by Formula (I):
wherein
R 1 , R 2 , R 3 , R 4 , and R 5 are each independently selected from the group consisting of hydrogen, methyl, ethyl, halogen, methoxy, ethoxy, —CONH-phenyl, and —NO 2 ; and
the pigment is selected from the group consisting of an azo pigment containing a benzimidazolone group, an azo pigment containing a quinoxalinedione group, a diketopyrrolo-pyrrole pigment, an unsubstituted quinacridone, a dichloro substituted quinacridone, and mixed crystals thereof, with the proviso that the mixed crystal of the unsubstituted quinacridone and/or the dichloro substituted quinacridone does not contain dimethyl substituted quinacridone.
2. The non-aqueous pigment dispersion according to claim 1 , wherein the dispersion synergist is represented by Formula (II):
3. The non-aqueous pigment dispersion according to claim 1 , wherein the pigment is selected from the group consisting of C.I. Pigment Yellow 180, C.I. Pigment Yellow 194, C.I. Pigment Yellow 213, and mixed crystals thereof.
4. The non-aqueous pigment dispersion according to claim 1 , wherein the diketopyrrolo-pyrrole pigment is selected from the group consisting of C.I. Pigment Red 254, C.I. Pigment Orange 71, and mixed crystals thereof.
5. The non-aqueous pigment dispersion according to claim 1 , wherein the non-aqueous dispersion medium consists of organic solvents.
6. The non-aqueous pigment dispersion according to claim 1 , further comprising a component that is curable by UV-radiation or e-beams.
7. An inkjet ink comprising:
the non-aqueous pigment dispersion according to claim 1 .
8. An inkjet ink set comprising:
one or more inkjet inks as defined by claim 7 .
9. An inkjet printing method comprising the steps of:
providing an inkjet ink as defined by claim 7 ; and
jetting the inkjet ink onto an ink-receiver.
10. The inkjet printing method according to claim 9 , wherein the inkjet ink includes at least two inkjet inks, and the at least two inkjet inks include a yellow inkjet ink and a magenta inkjet ink.