RESIN-COATED COMPOSITE STEEL SHEET WITH EXCELLENT LUBRICATING PROPERTY

摘要

PURPOSE:To enable good press forming to be effected without use of any lubricant by adjusting in a specific range a forming quantity of chromate treated film to be formed on a zinc or zinc alloy plated steel sheet, and the particle diameter of a solid lubricant for adding into organic resin to be applied thereto. CONSTITUTION:On a zinc or zinc alloy plated steel sheet, a chromate film of 200mg/m2 per one surface by metal Cr conversion in a chrome adhering quantity, and a resin coated layer of 0.2-4.0g/m2 in a applying quantity containing a crystalline solid lubricant of 3-100mum in the particle diameter are formed in this order. For a solid lubricating agent, an organic crystalline solid lubricant is selected and, for example, a wax of polyolefin or paraffin or fluorocarbon resin is preferable, and one of 120 deg.C or higher in melting point is adapted herein. As for the additional quantity of the solid lubricant to base resin, it is preferable that the range of organic polymer (base resin) : a solid lubricant=(1:0.02)-(1: 0.4). As for resin for coating, it is desirable to select one whose Tg is 20-120 deg.C. Besides, the additive quantity of silica to the resin is preferably allowed to be in the range of organic polymer (base resin) : silica=(1:0.05)-(1: 1).