Patent ID: 8153715

Claim:
In a printing ink composition comprising at least one pigment and a binder, the improvement comprising incorporating into the composition a binder comprising at least one polyvinyl acetal modified with amino or ammonium groups, prepared by acetalizing fully or partially hydrolyzed vinyl ester polymers containing ≧50 mol % of vinyl alcohol units in an aqueous medium with a) one or more aliphatic aldehydes having 1 to 15 carbon atoms, or an acetal, hemiacetal, or mixture thereof, and b) at least one aldehyde containing amino or ammonium group(s), or a hydrate, acetal, hemiacetal, or mixture thereof, wherein the degree of acetalization of the fully or partially hydrolyzed vinyl ester polymers with aliphatic aldehyde(s) is from 40 mol % to 80 mol %, and separating the polyvinyl acetal modified with amino or ammonium groups contained as a solid from the aqueous medium.