Biaxially oriented polypropylene (BOPP) and Biaxially oriented polyester (BOPET) are commonly produced in tender-frame lines. In these lines material is melted through a flat extrusion die (T-die) and solidified onto a cooled roller. Material is then stretched in machine direction in an MDO. Thereafter material is stretched in transversal direction in a TDO. These processes deliver a molecule orientation in both axes, this enhances many of their properties, particularly the mechanical, impact, barrier and optical properties. Most common applications of tender frames are BOPP and BOPET, which are probably the most common supports used in flexible packaging. BOPA, BOPLA are an other applications extruded in tender frames. These types of lines are also used for some label/sleeve films such as shrink film of PET-G, PS, PLA or PVC.
