The process consists of extruding the resin into a thin-walled tube by means of an extruder, and then using the polymer to have a better flow state under the action of the traction device, and Inflating it to a desired thickness by using compressed air. After cooling and setting, it becomes a film. The raw materials currently used for blown film are PE, PVC, PDVC, PP, PS, PA, EVA, PVA, and the like. In addition to a single layer film, a multilayer composite film has been developed.
After with the production methods of other plastic films, the extraction blown film has the advantages of simple equipment, low investment, high utilization of the machine, simple operation, no waste, low cost and easy soiling, and the film is pulled and blown. The expansion is improved, the mechanical properties are improved, and the finished product is cylindrical, and the welding process can be omitted for packaging. Disadvantages of extrusion blown film are poor uniformity of film thickness, low cooling rate, low transparency of film, and Limited by the cooling rate. The winding speed is generally not more than 10 m/min, and the yield is low.