Patent ID: 6281267
Filing Date: 2001-08-28
Classification: C09D

Abstract:
An ink-jet ink set for inkjet printing comprising a first ink and a second ink, wherein said first ink comprises at least one pH-sensitive polymer and a self-dispersing pigment and wherein said second ink comprises a multi-valent salt or has an appropriate pH, such that when said first ink and said second ink contact on a print medium, said polymer in said first ink will precipitate onto said print medium; and wherein said polymer comprises monomers having the structure: ##STR3##wherein R.sub.1 are independently selected from H or a C.sub.1 -C.sub.18 substituted or unsubstituted, branched or unbranched, alkyl, aromatic, or cyclic chain, optionally containing halogen, ester, ether, amine or amide functionalities; R.sub.2 is a group selected from the group consisting of a moiety containing a carboxylic acid group, primary amine, secondary amine, tertiary amine, or mixtures thereof; and R.sub.3 is a C.sub.1 -C.sub.18 substituted or unsubstituted, branched or unbranched, alkyl, aromatic, or cyclic chain, optionally containing ester, ether, amine or amide functionalities, said monomer present in an amount sufficient to provide a stable polymer when solubilized in water, yet will precipitate upon contact with said second ink, and providing that at least one monomer must be N-octylacrylamide, at least one monomer is a basic amine group, and one monomer is an acid group, wherein said polymer an acid number within a range of a 80-200 mgKOH/g of polymer.