| abstract |
A printing ink comprises a polymeric binder, a solvent and an adhesion promoting agent which is the reaction product of a zirconium orthoester and ethyl acetoacetate in which the molar ratio of zirconium to ethyl acetoacetate is from 1:1 to 1:4. Preferably, the inks are based on nitrocellulose or an ester type modified cellulose. The inks have been found to have adhesion and heat stability properties similar to inks containing titanium acetylacetonate but the zirconium additives have a much reduced tendency to discolor the ink. |