Graphic Packaging Holding Company announced that its wholly-owned subsidiaries, Graphic Packaging International, Inc. and Graphic Packaging International Canada, ULC, have agreed to acquire the assets of Seydaco Packaging Corp., and its affiliates National Carton and Coating Co., and Groupe Ecco Boites Pliantes Ltée.   Seydaco is a folding carton producer with a leading position in Canada focused on the foodservice, food, personal care, and household goods markets. Seydaco converts approximate...