PE protective film processing method that commonly used is blown film forming process. Here wuxi Isaac analyze PE protective film blowing process in details.
The process of producing blown film is to melt and extrude the material to form a tube loop and inflat the shape, and then process cooling, drawing, winding to finish the production. In the PE protective film blowing and forming process, depending on the extrusion and traction directions, it can be divided into three types: flat blowing, upper blowing, and lower blowing.
1. PE protective film flat extrusion upper blowing method is to use the right-angle blowing film die, that means the die discharge direction is perpendicular to the extruder. The extrusion tube loop is pulled upwards. And after a certain distance, it is clamped by the herringbone plate. The extruded tube is inflated into a bubble tube by the compressed air inlet from the bottom. Its lateral dimension is controlled by the compressed air volume and its longitudinal dimension is controlled by the speed of the traction. After cooling and shaping, the bubble tube can be made into the blown film. This method is suitable for PVC, PE, PS and HDPE.
2. The flat extrusion lower blowing method is to use the right-angle blowing film die and take the bubble tube from under the blowing film die. This method is particularly suitable for raw materials with low viscosity and plastic films requiring high transparency such as PP, PA, PVDC and etc.
3. The flat-extrusion flat blowing method is to use a straight die which is concentric with the extruder screw and make the bubble tube on the same level as the center line of the die. This method is only suitable for blowing small-diameter films, such as LDPE, PVC, and PS films. It can also be applied to the production of blown heat-shrinkable films.