Chrome free resin composition having good alkaline resistance and forming properties, method for surface treating steel sheet using the same and surface-treated steel sheet

摘要

The invention provides a chromium-free resin constituent with excellent corrosion resistance, alkali resistance, processability, electroconductibility, and chemical resistance, a method for carrying out a surface treatment on a steel plate, and a steel plate manufactured according to the method. The surface treatment steel plate is prepared through coating the steel plate by the resin constitute; after the steel plate is dry, the quantity of resin mixture adhered to the steel plate is in the scope of 300 to 1800mg/m2, wherein, based on the overall solid content of the resin constituent, the resin constituent consists of: mixture of hard urethane resin and 10-90 weight percent of soft urethane resin; based on the overall solid content of the mixture, the mixture contains 5-95 weight percent of soft urethane resin and 5-95 weight percent of hard urethane resin; 1-20 weight percent of Ti or Zr and the like organic oxide; 0.1-10.0 weight percent of at least one of compounds selected from a group composed of aluminium phosphate, aluminium dihydrogen phosphate, phosphate monozinc and hydrated manganese phosphate; solvent.