EXCELLENT HEAT-DISSIPATING BLACK RESIN COMPOSITION, METHOD FOR TREATING A ZINC COATED STEEL SHEET USING THE SAME AND STEEL SHEET TREATED THEREBY

摘要

There are provided a heat-dissipating black resin composition having excellent physical properties such as heat-dissipating property, workability, corrosion resistance, solvent resistance, coating adherence and gloss and being free from chromium and used for surface treatment of a zinc coated steel sheet, a method for treating a zinc coated steel sheet, and a zinc coated steel sheet treated thereby. The heat-dissipating black resin composition includes, based on 100 parts by weight of the heat-dissipating black resin composition: 10 to 60 parts by weight of a resin composition which at least one main resin and a melamine-based curing agent are mixed in a weight ratio of 10:2-7, the main resin being selected from the group consisting of polyester resin, epoxy resin, polyolefin resin, polyurethane resin, fluorine resin, phenol resin, acryl resin and polycarbonate resin; 1 to 10 parts by weight of at least one pigment selected from the group consisting of carbon black and carbon nano tube; 1 to 10 parts by weight of a matting agent; and the balance of a solvent. Also, the method for treating a steel sheet with a heat-dissipating black resin composition includes: coating a steel sheet with the heat-dissipating black resin composition so that a thickness of a dry coating film is in a range of 3 to 30 micrometers; and drying the heat-dissipating black resin composition, and the steel sheet is treated according to the method. The resin-coated steel sheet includes a thin resin layer, shows excellent heat- absorbing/dissipating properties, has excellent physical properties such as corrosion resistance, press workability, surface electrical conductivity and solvent resistance, and is environmental- friendly since it is free from a chromium component.