Patent ID: 9228111
Filing Date: 2016-01-05
CPC Classification: C08G,C08K,C09D,Y10T

Claim Text:
1. A surface-treated steel sheet having a resin layer formed by coating a resin composition for surface treatment of a steel sheet comprising a binder resin, a graphene, and a solvent, wherein the binder resin is a urethane resin, wherein the urethane resin includes 5 to 95 parts by weight of a soft urethane-based resin and 5 to 95 parts by weight of a hard urethane-based resin based on a solid content of the urethane resin, wherein the soft urethane-based resin is a polyurethane resin prepared from isophorone diisocyanate, dibasic acid, and polyvalent alcohol; or a polyurethane resin prepared from acryl polyol and polyisocyanate, wherein the soft urethane-based resin has a number average molecular weight of 5,000 to 300,000, wherein the hard urethane-based resin is a polyurethane resin prepared from 4,4′-bis(ω-hydroxyalkyleneoxy)biphenyl and methyl-2,6-diisocyanatehexanoate, wherein the hard urethane-based resin has a number average molecular weight of 200,000 to 2,000,000, wherein the hard urethane-based resin has a Shore A hardness of 40 to 90, wherein the graphene is surface-treated with at least one hydrophilic functional group, wherein the hydrophilic functional group is COOH or COO wherein the resin layer has a thickness of 2.5 μm or less.