A lid member for a food container having a layered structure in which a surface sheet is laid on a composite sheet, said surface sheet including an easily-peelable area that is easily separated from the composite sheet, formed by applying a lubricant between the surface sheet and the composite sheet,...http://www.google.es/patents/US6959832?utm_source=gb-gplus-sharePatente US6959832 - Lid member for food container
