Patent ID: 8216694

Claim:
A zinc- and zinc alloy-coated steel sheet having a coating film formed with a coating composition for zinc- and zinc alloy-coated steel sheets comprising: 1 to 30% by weight of hypophosphorous acid, 0.1 to 10% by weight of manganese, 0.01 to 5% by weight of a polyvinyl compound, zinc oxide and the balance of water, wherein the zinc oxide is comprised in such a content that, when 50 ml (milliliters) of the coating composition is neutralized and titrated with 0.1N NaOH, the NaOH used for the neutralization titration is present in an amount of 10.0 ml (milliliters) or less, and a content of free acid in the coating composition is adjusted to such an amount that, when 50 ml (milliliters) of the coating composition is neutralized and titrated with 0.1N NaOH, the NaOH used for the neutralization titration is present in an amount of 10.0 ml (milliliters) or less, wherein a dried coating weight of the coating composition coated onto the coating layer is in a range of 100 to 2000 mg (milligrams)/m 2 (square meters) per one side of the steel sheet.