AGENT FOR IMPARTING WATER RESISTANCE, INK COMPOSITION AND REACTION LIQUID AND METHOD FOR INK JET RECORDING WITH TWO LIQUIDS

摘要

PROBLEM TO BE SOLVED: To obtain a water resistance-imparting agent which can realize images which scarcely blot and have excellent water resistance, when added to an ink composition, by including a cationic water-soluble resin having a specific structure. SOLUTION: This water resistance-imparting agent contains a cationic water- soluble resin comprising a (co)polymer which comprises repeating units of formula I (R1 is H or methyl; R2 and R3 are each a 1 to 3C alkyl in an amount of 100 to 0 mol.% and repeating units of formula II [R4 is H or methyl; R5 to R7 are each a 1 to 3C alkyl; Z-is a counter ion; (k) and (l) are each 1, 2 or 3] and contains a carboxyl group at one of molecular terminals and an aromatic ring at the other. The agent for imparting water resistance preferably has a number-average mol.wt. of 1,000 to 10,000 by gel permeation chromatography, and is preferably added to an ink composition in an amount of 0.2 to 20 wt.%. When added to a reaction liquid for an ink jet recording method, images having high color concentrations and reduced printing irregularity can be obtained.