Polypropylene Extrusion Coating: Adhere to its Rules or it Will Not Adhere to the Substrate, 2001 Polymers Laminations & Coatings Conference Proceedings
A polypropylene blend is used as a barrier layer in a paperboard orange juice carton. The carton structure is made in two extrusion passes: first pass, PP-paperboard-LDPE; and second pass, LDPE is coated over the PP layer to form the final structure, LDPE-PP-paperboard-LDPE. PP adhesion is excellent after the first pass, but after the second pass, PP adhesion fails completely in certain wide areas over the coated structure. Adhesion is excellent in other areas.