Breathable film is extruded from the extruder t-dies, and in which polyethylene resin is compounded with caco3. Due to its fine surface pores, it is permeable to air but not to liquid (sort of water). The breathable film is very useful as it allows transmission of gases but it remains water proof. Major uses include the back sheet of diapers and sanitary napkins, disposable work cloth, and house-wrapping for wooden houses, etc.