A radiation curable inkjet ink including an adhesion promoter including (1) at least one a free radical polymerizable group selected from the group consisting of an acrylate, a methacrylate, an acryl amide and a methacryl amide; (2) at least one aliphatic tertiary amine; and (3) at least one carboxylic acid or salt thereof with the proviso that the carboxylic acid is linked to an aliphatic tertiary amine via a divalent linking group selected from the group consisting of an optionally substituted methylene group and an optionally substituted ethylene group.

A radiation curable inkjet ink including an adhesion promoter including (1) at least one a free radical polymerizable group selected from the group consisting of an acrylate, a methacrylate, an acryl amide and a methacryl amide; (2) at least one aliphatic tertiary amine; and (3) at least one carboxylic acid or salt thereof with the proviso that the carboxylic acid is linked to an aliphatic tertiary amine via a divalent linking group selected from the group consisting of an optionally substituted methylene group and an optionally substituted ethylene group.