Patent ID: 8461255

Claim:
A hydrophilic resin comprising a first aqueous resin and a second aqueous resin, wherein the first aqueous resin is an aqueous polyurethane resin obtained by reaction of an isocyanate group-terminated prepolymer with a chain extender containing diamines such that the equivalent ratio of an amino group in the chain extender relative to the isocyanate group in the isocyanate group-terminated prepolymor is 0.8 to 1.2, wherein the isocyanate group-terminated prepolymer is obtained by reaction of components consisting of: a polyisocyanate consisting of bis(isocyanatomethyl)cyclohexane, a polyol component containing polyoxyethylen glycol having the number average molecular weight of 300 to 6000, and a polyoxyethylene side chain-containing active compound having two or more hydroxyl groups or isocyanate groups at its molecular terminal and having a polyoxyethylene group in its side chain, the second aqueous resin is an aqueous polyurethane resin obtained by reaction of an isocyanate group-terminated prepolymer with a chain extender containing diamines such that the equivalent ratio of an amino group in the chain extender relative to the isocyanate group in the isocyanate group-terminated prepolymer is 0.8 to 1.2, wherein the isocyanate group-terminated prepolymer is obtained by reaction components consisting of: a polyisocyanate consisting of methylenebis(cyclohexyl isocyanate), a polyol component containing polytetramethylene ether glycol having the number average molecular weight of 300 to 10000, and an ionic group-containing active compound having both carboxylic acid and two or more hydroxyl groups, wherein the content of the ionic group-containing active compound is 1.5 to 8 wt % relative to the total amount of the raw materials of the second aqueous resin.