Plastic film is a thin continuous polymeric material. Thicker plastic material is often called a "sheet". These thin plastic membranes are used to separate areas or volumes, to hold items, to act as barriers, or as printable surfaces.
Film strip (photographic film)6 mil polyethylene plastic sheet as vapor barrier in constructionConfectionery packaging made of PLA-blend bio-flex bioplasticShrink-wrapped OH-58 Kiowa helicopters to be shipped.
Semiembossed film – Semiembossed film can be used as a liner to the calendered rubber to retain the properties of rubber and also to prevent dust and other foreign matters from sticking to the rubber while calendering and during storage
A tube of extruded film being blown to expand
Plastic films are usually thermoplastics and are formed by melting for forming the film.[2]
Cast – Plastics extrusion can cast film which is cooled or quenched then wound up on a roll.
Extruded film can be stretched, thinned, or oriented in one or two directions. Blown or tubular process forces air into an extruded ring to expand the film. Flat tenter frames stretch the extruded film before annealing.[3][4]
Calender rolls can be used to form film from hot polymers[5]
Solution deposition is another film forming process.
Skiving is used to scrape off a film from a solid core (sometimes used to make PTFE thread seal tape)
Coextrusion involves extruding two or more layers of dissimilar polymers into a single film
Lamination combines two or more films (or other materials) into a sandwich.[6][7]
US 5072493,Hommes, William J.&Keegan Jr., John J.,"Apparatus for drawing plastic film in a tenter frame",published 1991-12-17, assigned to E. I. du Pont de Nemours & Co.
US 5167894,Baumgarten, Wilfried W.,"Apparatus comprising an extruder and a calender for producing sheets and/or foils from plastic or rubber mixtures",published 1992-12-01, assigned to Paul Troester Maschinenfabrik
