Bi-Oriented Polypropylene (BOPP) refers to the manufacture of polypropylene films using an orienting system. BOPP films are manufactured using a tenter frame sequential process or the double bubble process, in which a polypropylene (PP) film is oriented in two directions (machine and transverse directions). BOPP films are typically used for packaging snacks, pasta, and confectionary goods, and as collation wrap for multi-packs.
The main features of BOPP films are improved stiffness, high tensile strength, excellent optics and good water vapor barrier properties. BOPP films range from 15 to 50 microns and are most commonly 15 to 30 microns. BOPP films can be monolayer or co-extruded structures, and transparent, opaque, or metallized. Additionally, BOPP films can be treated with acrylic and PVDC coatings for better sealability and barrier properties. The films use mainly homopolymer PP and random copolymer PP.