ORGANIC COMPOSITE COATED STEEL PLATE HAVING EXCELLENT OUTER SURFACE CORROSION RESISTANCE AND IMAGE CLARITY AND ITS PRODUCTION

摘要

PURPOSE:To secure mainly excellent outer surface corrosion resistance and image clarity by laminating a specified chromate layer as a primary layer and a specified organic film consisting essentially of block urethane modified epoxy resin as secondary layer on a zinc electroplated steel plate. CONSTITUTION:An organic composite coated steel plate is constituted of chromate layer provided as a primary layer on a zinc electroplated steel plate and, upper the primary layer, an organic coating layer as secondary layer. The chromate layer is specified to 10-200mg/m3 attached quantity expressed in terms of metallic chromium. On the other hand, an organic coating is composed by adding a rust preventive additive (D) to block urethane-modified epoxy resin (C) at a wt. ratio of C/D=90/10-40/60 which is formed by mixing block urethane (B) consisting of polyol, polyisocianate and a blocking with modified epoxy resin (A) consisting of an epoxy resin and a multifunctional amine at a wt. ratio of A/B=95/5-50/50, and the thickness of the coating is specified to 0.2-2mum.