The breathable film unit is a combination of casting equipment and MDO longitudinal drawing equipment, which can produce both cast film and breathable film. By adding approximately 50% Caco3, the breathable membrane has a unique microporous structure after being stretched by MDO. These high-density microporous structures distributed on the surface of the film can allow liquid or water vapor molecules to pass through while blocking liquid leakage, hence the name "breathable membrane". The significant feature of breathable film is not only in its "breathability", but also in its textile like feel. It is an ideal choice for the bottom film of diapers and sanitary napkins.