摘要:
Disclosed is a cationic water-soluble resin which comprises a (co)polymer of, in formula (I), repeating units (a) represented by formula (a) and repeating units (b) represented by formula (b), the content of the repeating units (a) in the (co)polymer being 100 to 0% by mole, the (co)polymer having in its molecule a carboxyl-containing group as one of the terminal groups and an aromatic ring-containing group as the other terminal group. The addition of this resin to ink compositions can realize the formation of images possessing excellent waterfastness and lightfastness and having no significant feathering or color bleeding. Likewise, the addition of this resin to a reaction solution for ink jet recording involving the deposition of two liquids, an ink composition and a reaction solution, onto a recording medium, can realize the formation of images possessing excellent waterfastness and lightfastness and no significant feathering or color bleeding. wherein R 1 represents hydrogen or methyl; R 2 and R 3 represent C 1-3 alkyl; R 4 represents hydrogen or methyl; R 5 , R 6 , and R 7 represent C 1-3 alkyl; Z - represents a counter ion; and k and 1 are each 1, 2, or 3.