SURFACE TREATED STEEL PLATE EXCELLENT IN CORROSION RESISTANCE, WELDABILITY, LUBRICITY, CONTINUOUS PUNCHING PROPERTY AND TOPCOATING PROPERTY AND ITS MANUFACTURE

摘要

PURPOSE:To markedly improve the life of a punch and a die at the time of the perforation due to the punch by together using self-dispersion type fluoroplastic having a hydrophilic functional group and a water-dispersible resin. CONSTITUTION:A plated steel plate is subjected to chromate treatment by an appropriate method. A polymerizable ethylenic unsaturated compound is added to a dispersion of an ethylene/unsaturated carboxylic acid copolymer to be emulsified and polymerized therewith and, further, an aqueous solution prepared by adding 5-25 pts.wt. of silica having a particle size of 2-50nm and 5-25 pts.wt. of self-dispersion type fluoroplastic having a hydrophilic functional group to 100 pts.wt. of water-dispersible resin solution crosslinked with amine on a solid basis is compounded with said dispersion in an amount of 5-40wt.% as a total solid component to prepare a coating solution which is, in turn, applied to the treated steel plate. Subsequently, the coated steel plate is dried so that the max. temp. thereof becomes 100-250 deg.C to form an org. composite film in an adhesion amount of 0.3-3g/m2 on a dry wt. basis.