At present, there are two main methods for the production of PVB interlayer film, one is the over-roll method and the other is the water-pass method. The over-roll method is to produce a film by casting two rolls or three rolls (with a light roll and a pattern roll). The over-roll method has low investment, the technology is relatively mature, and the equipment is relatively easy to operate. The water-passing method is a process that is generally believed to produce a film with better whiteness and a more uniform pattern. It uses a water tank to cool the characterization instead of a roller, and then removes water, thickness, oven, cooling, separator composite, and traction. Finally, the volume is collected. Because the over-water method has more advantages than the over-roll method, it is used by more and more manufacturers. The following points in the production process of the water-passing method require special attention: