EASY-OPEN CAN LID MADE OF RESIN-COATED STEEL SHEET AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an easy-open can lid made of resin-coated steel sheet which can meet characteristics required for food can materials and to provide a method of manufacturing the easy-open can lid made of resin-coated steel sheet.SOLUTION: Opening grooves are formed on both surfaces of a can lid made of resin-coated steel sheet and a can is opened by breaking the opening grooves. The resin-coated steel sheet has resin layers which principally comprise polyester and are made of a double-layer structure on both surfaces. The resin layer as an adhesive layer with a steel sheet contains a block-free isocyanate compound and a residual degree of orientation of the polyester resin layer formed on the upper layer of the adhesive layer is 2-30%. A bottom cross-section shape of the opening groove assumes a curved surface having a radius of 0.1-0.5 mm and the thickness of the thinnest part is 0.035-0.075 mm. The can lid is manufactured by using a pair of upper and lower dies being curved surface dies having a top end radius of 0.1-0.5 mm with respect to a can lid panel made of a steel sheet of which both surfaces are covered with a resin layer and by performing extrusion molding such that the thickness of the thinnest part falls into the range of 0.035-0.075 mm.