Use of hyperbranched polyurethanes for producing printing inks

1. A process for the preparation of printing inks or of printing varnishes, said process comprising mixing or dispersing from a 10–50% by weight of one or more binders, at least one of the binders being a hyperbranched polyurethane having a variant molecular composition arid structure, wherein the hyperbranched polyurethane has on average at least 4 functional groups, from 20–80% by weight of a solvent or a mixture of different solvents, and, if applicable from 5 to 25% by weight of one or more colorants, and optionally up to 20% by weight of further additives, and wherein the solvent is water or a predominantly aqueous solvent mixture.

2. The process as claimed in claim 1 , wherein the hyperbranched polyurethanes have functional groups which may be identical or different and are selected from the group consisting of—COOH, —COOR, —CONHR, —CONH 2 , —OH, —SH, —NH 2 , —NHR, —NR 2 , —SO 3 H, —SO 3 R, —NHCOOR, —NHCONH 2 , —NHCONHR, —CN and salts of said groups, wherein R denotes optionally substituted alkyl or aryl.

3. A process for the preparation of printing inks or of printing varnishes, said process comprising mixing or dispersing a hyperbranched polyurethane having a variant molecular composition and structure with other components, wherein the hyperbranched polyurethanes have functional groups which are identical or different and are selected from the group consisting of —COOH, —CONH 2 , —OH, —SH, —NH 2 , —NHR, —NR 2 , —SO 3 H and salts of said groups wherein the hyperbranched polyurethanes additionally have photochemically crosslinkable groups, and said process further comprises a solvent or a mixture of different solvents, and wherein the solvent is water or a predominantly aqueous solvent mixture.

4. The process as claimed in claim 1 , wherein the hyperbranched polyurethanes have 4–30 functional groups.

5. A printing ink, comprising from 10–50% by weight of one or more binders, from 20–80% by weight of a solvent or a mixture of a plurality of solvents, from 5–25% by weight of at least one colorant, and optionally up to 20% by weight of further additives, wherein at least one of the binders is a hyperbranched polyurethane, and wherein the solvent is water or a predominantly aqueous solvent mixture.

6. A printing ink as claimed in claim 5 , wherein the solvent mixture comprise organic solvents.

7. A radiation-curable printing ink, at least comprising at least one colorant, one or more binders and optionally further additives, wherein at least one of the binders is a hyperbranched polyurethane which has photochemically crosslinkable groups, and a solvent or a mixture of different solvents, and wherein the solvent is water or a predominantly aqueous solvent mixture.

8. A radiation-curable printing ink as claimed in claim 7 , wherein the printing ink further comprises at least one photoinitiator or a photoinitiator system.

9. A radiation-curable printing ink as claimed in claim 8 , wherein the printing ink additionally comprises at least one reactive diluent.

10. A printing varnish, comprising from 10–50% by weight of one or more binders, from 20–80% by weight of a solvent or a mixture of a plurality of solvents, and optionally up to 20% by weight of further additives, wherein at least one of the binders is a hyperbranched polyurethane, and wherein the solvent is water or a predominantly aqueous solvent mixture.

11. A printing varnish as claimed in claim 10 , wherein at least one of the binders is a hyperbranched polyurethane which has photochemically crosslinkable groups, and wherein said printing varnish is radiation curable.

12. A process for priming print media or for coating printed print media, said process comprising applying the printing varnish of claim 10 to the print media, either before or after printing.