Polymeric dispersants and non-aqueous dispersions

1. A non-aqueous pigment dispersion comprising:

an organic pigment;

a non-aqueous dispersion medium; and

a polymeric dispersant including at least one oxalylamide structural unit according to Formula (I):

wherein:

R1 represents a first polymeric moiety selected from the group consisting of a linear polymeric moiety, a star shaped polymeric moiety, a dendritic polymeric moiety, a branched polymeric moiety, and a hyperbranched polymeric moiety; and

R2 represents a second polymeric moiety selected from the group consisting of a polyester, a polyether, a polyamide, a polyacrylate, a polymethacrylate, or copolymers thereof; and

the organic pigment is a quinacridone pigment.

2. The non-aqueous pigment dispersion according to claim 1 , wherein the first polymeric moiety is substituted by at least one structural unit according to Formula (II):

wherein:

R3 represents a functional group including at least one nitrogen containing five or six membered heteroaromatic ring.

3. The non-aqueous pigment dispersion according to claim 1 , wherein the first polymeric moiety is a branched polymeric moiety or a hyperbranched polymeric moiety.

4. The non-aqueous pigment dispersion according to claim 1 , wherein the polymeric dispersant is a polyethylene imine derivative.

5. The non-aqueous pigment dispersion according to claim 1 , wherein the second polymeric moiety is selected from the group consisting of a polyester and a polyether.

6. The non-aqueous pigment dispersion according to claim 2 , wherein R3 comprises at least one nitrogen containing five or six membered heteroaromatic ring selected from the group consisting of benzimidazole, imidazole, and pyridine.

7. The non-aqueous pigment dispersion according to claim 6 wherein the at least one nitrogen containing five or six membered heteroaromatic ring is pyridine.

8. The non-aqueous pigment dispersion according to claim 1 , wherein the polymeric dispersant is represented by Formula (III):

wherein:

R4 represents a polymeric chain selected from the group consisting of a polyether and a polyester;

R5 represents a branched polymeric core or a hyperbranched polymeric core;

k represents an integer from 0 to 600; and

p represents an integer from 1 to 900.

9. The non-aqueous pigment dispersion according to claim 1 , wherein the polymeric dispersant is represented by Formula (IV):

wherein:

R6 represents a branched polymeric core or a hyperbranched polymeric core;

R7 represents a polymeric chain selected from the group consisting of a polyether and a polyester;

R8 represents a functional group including at least one nitrogen containing five or six membered heteroaromatic ring;

n represents an integer from 1 to 900;

m represents an integer from 0 to 720; and

o represents an integer from 0 to 600.

10. A non-aqueous pigment dispersion comprising:

a pigment;

a non-aqueous dispersion medium; and

a polymeric dispersant including at least one oxalylamide structural unit according to Formula (I):

wherein:

R1 represents a first polymeric moiety selected from the group consisting of a linear polymeric moiety, a star shaped polymeric moiety, a dendritic polymeric moiety, a branched polymeric moiety, and a hyperbranched polymeric moiety;

R2 represents a second polymeric moiety selected from the group consisting of a polyester, a polyether, a polyamide, a polyacrylate, a polymethacrylate, or copolymers thereof; and

the pigment dispersion is curable by UV radiation or an e-beam.

11. The non-aqueous pigment dispersion according to claim 1 , wherein the pigment dispersion is an inkjet ink.

12. A non-aqueous inkjet ink set comprising:

at least one inkjet ink containing a non-aqueous pigment dispersion comprising:

a pigment;

a non-aqueous dispersion medium; and

a polymeric dispersant including at least one oxalylamide structural unit according to Formula (I):

wherein:

R1 represents a first polymeric moiety selected from the group consisting of a linear polymeric moiety, a star shaped polymeric moiety, a dendritic polymeric moiety, a branched polymeric moiety, and a hyperbranched polymeric moiety; and

R2 represents a second polymeric moiety selected from the group consisting of a polyester, a polyether, a polyamide, a polyacrylate, a polymethacrylate, or copolymers thereof.

13. A method for preparing a non-aqueous pigment dispersion comprising the steps of:

a) providing the polymeric dispersant and the pigment as defined in claim 1 ; and

b) milling the pigment in the dispersion medium in the presence of the polymeric dispersant.