Atlantic Corp. of Wilmington announced that it has signed a definitive agreement to purchase International Paper's three largest paperboard converting facilities in Greensboro, Hazleton, Pa., and Sturgis, Mich. Memphis-based International Paper has reached a definitive agreement to sell its Greensboro operation to Wilmington-based packaging firm Atlantic Corp., which plans to maintain and grow the Gate City facility at 3900 Spring Garden St. International Paper plans to also sell its paperboard converting facilities in Hazleton, Pa., and Sturgis, Mich., to Atlantic Corp. for an undisclosed price.