At the same time, the airtight layer film to be used on the opening device is guided through the film conveyor belt and then enters the centering composite platform. On the composite platform, the airtight layer film is compounded with the transition layer film to form the inner liner layer. . The compounded inner liner is taken up by a film conveyor belt and taken up by a take-up device. A hard polyester film is placed on the roll. Similarly, the coiling temperature is lower than 40° C., and the inner liner film is wound on an I-shaped reel. At this point, the production of the inner liner is completed and the molding process is ready for use. The main technical parameters The main technical parameters for the production of the inner lining layer by the four-roll calendering method are: calender power 4×40 kW; single-layer film thickness 0.4 to 3.0 mm; film width compounding centering error ≤2 mm; film winding homogeneity error. The main advantages and disadvantages The advantages of the four-roll calendering process for the production of the inner lining layer are mainly manifested in the following aspects: (1) the production speed is faster; (2) the surface quality of the produced film is better; (3) the temperature of the rubber material is relatively low; 4) Lower equipment investment. The four-roll calendar method has the following disadvantages in producing the inner liner: (1) Since the rubber material fed into the gap of the calender roll is a reciprocating pendulum strip, the rubber material has a certain amount of accumulated on the roll gap. The stacking glue rolls into the nip after rolling several times, so that it is easy to entrap the air so that the pressed film contains bubbles. (2) Because of the easy formation of air bubbles, the calendering method is only suitable for the production of films that are not too thick for calendering. Generally, the thickness of the rolled film is not more than 3 mm. For thick products (such as the transition layer film), only legal production is allowed. . (3) Because the four-roll calender rollers are not type and the laminating method is adopted, the cross-section shape of the inner liner produced by the calendering method can only approximately meet the structural design requirements. (4) The thickness error of the film is affected by the amount of accumulated glue. Therefore, the feeding should be carried out continuously and evenly to keep the amount of accumulated glue constant. It cannot be done for a long time or it will cause problems such as uneven thickness and thickness.