| 摘要 |
The present invention relates to a Cr-free pretreatment solution and a manufacturing method of a coated steel sheet using the same. The purpose of the present invention is to improve the corrosion resistance, chemical resistance and cohesive strength without using a primer by providing a Cr-free pretreatment solution which has silicasol, solvent, water-dispersible nanosilica, inorganic compound, surface tension control agent and crosslinking agent. For the purpose, the present invention comprises: 5-8 wt% silicasol, 19-23 wt% solvent, 5-8 wt% water-dispersible nanosilica, 0.3-0.8 wt% inorganic compound, 0.01-0.05 wt% surface tension control agent, 1-5 wt% crosslinking agent and 55-70 wt% water, and the ratio of each component can be selected if the total ratio can be maintained as 100 wt%. |
