Abstract: In has been desired to employ adhesion promoters in printing inks to promote the adhesion of the ink to a plastic substrate but hitherto the available adhesion promoters have tended to discolor the ink and in certain cases to produce an ink containing a somewhat objectionable odor.A new printing ink has been developed which is based on a polymeric binder, a solvent therefor and an adhesion promoting agent which is the reaction product of a titanium orthoester and either a monoalkyl phosphate or a dialkyl phosphate or a mixture thereof in such proportions that the molar ratio of titanium to phosphate expressed as Ti:P is from 4:1 to 1:2.

Abstract: A new organotitanate which is a reaction product of a titanium orthoester and at least a monoalkyl phosphate in which the alkyl group contains up to 6 carbon atoms and in which the total molar ratio P:Ti in the product is less than 2.The monoalkyl phosphates preferably contain up to 5 carbon atoms in the alkyl group and the organotitanate reaction product can also be prepared from a dialkyl phosphate in addition to the monoalkyl phosphate. Most preferably the alkyl group of the titanium orthoester is either an isopropyl group or a butyl group.The new reaction products are of use as adhesion promoters in printing inks.