Opp film is a kind of polypropylene film. Because the production process is multi-layer extrusion, it is called co-extrusion oriented polypropylene film.
If there is a process of biaxial stretching in the processing, it is called (Biaxially Oriented Polypropylene Film) Bopp film.
In contrast to the co-extrusion process, the other is called Casting Polypropylene Film Cpp film.
Opp: Unidirectional stretch
Bopp: Two-way stretch, landscape and portrait
Cpp: Cast film, not stretched