STEEL SHEET HAVING ALKALI-SOLUBLE LUBRICATING FILM, METHOD FOR PRODUCING SAME, AND COMPOSITION

摘要

The present invention provides a steel sheet which has an alkali removable lubricating film on the surface, and which is characterized in that: the lubricating film has a first layer that contains (A) a polyethylene oxide having a weight average molecular weight of 50,000-500,000 and (B) a copolymer of (X) a styrene hydrocarbon compound or an olefin hydrocarbon compound having 3 or more carbon atoms and (Y) a polymerizable unsaturated compound having a carboxylic acid anhydride group and/or a polymerizable unsaturated compound having a carboxy group, said compounds being copolymerizable with the compound (X), wherein some or all of the carboxylic acid anhydride groups and the carboxy groups contained in the copolymer may be ammonia-modified, imidized or blocked by an alcohol, with the mass ratio of the component (B) relative to the total of the component (A) and the component (B) being more than 5% by mass but less than 50% by mass, and a second layer that is provided on the first layer and is formed of an oil layer that contains an oil component having a kinematic viscosity of 3-32 mm2/s (at 40°C); the total adhesion amount of the component (A) and the component (B) is 0.1-1.0 g/m2; and the adhesion amount of the oil layer is 0.1-3.0 g/m2.