| 摘要 |
PURPOSE:To obtain a heavy corrosionproof coated steel material having cathode release-resistant capacity corresponding to required capacity by bonding a chromate layer, a primer layer and an org. resin layer to the surface of a steel material. CONSTITUTION:A chromate layer formed using a chromate treatment agent containing vapor phase silica having 2-4 hydroxy groups per a specific surface area of 1nm<2> in an amt. of 2.0-7.0 times with respect to the total amt. of chromium on a wt. ratio and partially reduced so that the wt. ratio of trivalent chromium to the total amt. of chromium becomes 0.1-0.7 is applied to the surface of a steel material in an amt. of 50-1000mg/m<2> as the total amt. of chromium and a primer layer with a thickness of 10mum containing 1.0-6.0mol/kg of epoxide is provided on the chromate layer and, further, an org. resin layer (e.g.; modified polyolefin layer, polyolefin resin layer) is formed thereon. As a result, a heavy corrosionproof coated steel material having cathode release-resistant capacity corresponding to required capacity can be obtained. |
