Forming process of nylon coextrusion plastic film

Melt extrusion is one of the most widely used single-layer film forming methods. The main equipment is screw extruder. According to the different structure of chessboard, the melt extrusion method can be divided into annular mold method and narrow slot T-shaped mold method. The film produced by the former is called blow molding film, and the latter is flat film, called injection film.

 

 

 

 

In extrusion blow molding, the plastic particles are heated and plasticized into viscous fluid in the extruder, and then extruded from the die head into a tubular blank, which is clamped and drawn; compressed air is blown into the hollow channel of the mandrel towel to inflate the tube bad material into a tubular film, which is cooled and rolled up to obtain the finished tube film. In the process of blow molding, the film has a certain degree of tensile orientation in both vertical and horizontal directions. The degree of orientation is related to the draft ratio (tube blank wall thickness / film wall thickness) and blowing ratio (film bubble diameter / tube blank diameter). Increasing the blowing ratio can increase the directional degree of the film, and improve the brightness and luster. However, if the blowing ratio is too large, the film will wrinkle and the thickness will be uneven Generally 2-3. Because of its compact equipment and less investment, extrusion blow molding method is widely used in the production of PE, PVC and other films, but it is affected by the slow cooling rate.