Non-combustible color steel sheet for household appliances and building materials and method for manufacturing same

A method for manufacturing an incombustible color-coated steel sheet, comprising the steps of:

• (a) applying an under-coating agent to a base steel sheet, followed by heat drying, thereby forming a pretreatment layer;
• (b) applying a primer coating composition to the pretreatment layer, followed by heat drying, thereby forming a primer layer;
• and
• (c) applying a flame-retardant coating composition to the primer layer, followed by drying and curing at a temperature of 200° C., thereby forming a flame-retardant coating layer, the flame- retardant coating composition comprising, based on 100 parts by weight of the flame-retardant coating composition, 15-20 parts by weight of silica sol, 5-15 parts by weight of polyurethane resin, 40-70 parts by weight of a solvent, 1-3 parts by weight of an acid catalyst, 0.1-2.0 parts by weight of an acid stabilizer, and 5-20 parts by weight of a pigment,
• wherein the flame-retardant coating layer has a thickness of 5 to 10 μm.