There is no uniform regulation for the classification of film varieties. Usually people are accustomed to the following three classification methods:
⑴ Classified according to the raw materials used in film forming: polyethylene film, polypropylene film, polyvinyl chloride film and polyester film, etc.
⑵ Classified by film use: agricultural film (here, according to the specific use of agricultural film, it can be divided into mulch film and greenhouse film); packaging film (package film can be divided into food packaging film and various industrial products according to its specific use) Packaging film, etc.) and breathable films for special environments and special purposes, water-soluble films and films with piezoelectric properties.
⑶ Classification according to the film forming method: a film that has been extruded and plasticized and then blown molded is called a blown film; a film that is plasticized by extrusion and then melted from the die is called a cast film ; A film made of plasticized raw materials rolled by several rollers on a calender is called a calendered film.
