Method of manufacturing a wall ironed can
AssigneeCMB Foodcan plc
InventorsPeter J. Heyes, Ian M. Leishman, Kevin J. Pope
Life of this patent
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Abstract
In a method of drawing and wall ironing a can body, a blank (1) is cut from a laminate of aluminium or alloy and a polyester film. The blank is lubricated and drawn to a cup (7) having a side wall (8), which is then wall ironed. A terminal margin (14) of the side wall (13) of the wall ironed can is heated to a temperature above 100.degree. C. but below the crystalline melting point of the polyester film in order to prevent delamination of the polyester film from the side wall of the can during subsequent washing of the can. A benefit of the process is that the heating of the side wall margin (14) does not soften the aluminium or aluminium alloy body.
Claims14
A method of forming a can body from a laminate of sheet metal and a polymeric film by:
- (a) applying a lubricant to both surfaces of the laminate and cutting a blank from the laminate;
- (b) drawing the blank to a cup having a bottom wall and a side wall upstanding from the periphery of the bottom wall;
- (c) reducing the thickness of the side wall by pushing the cup through a wall ironing die, and
- (d) washing the can body,
- wherein,
- in step (a) the laminate is a laminate of sheet aluminium or aluminium alloy and a film of an amorphous linear polyester or copolyester;
- and after step (c) but before step (d) a terminal margin only of the side wall of the wall ironed cup is heated to a temperature above 100.degree. C. but below the crystalline melting point of the film.
Dependencies are inferred from the claim text.