Polyethylene self sealing film is a type of film with a special structure in extrusion blown film. The special feature of this thin film structure is that there is an anchor shaped protrusion and groove on the finished film, and the performance of the film is exactly the same as that of ordinary polyethylene film. The film packaging bag made of polyethylene self sealing film has a zipper like concave and convex groove at the opening, which can be opened and closed with just a little force, and can be used repeatedly. However, the packaging bag cannot be easily opened by the expansion force or external pressure of the packaged material inside the bag.
The self sealing plastic film bag made of this self sealing film has a novel and unique appearance, reliable sealed packaging items, non-toxic, odorless, pollution resistant, and is both light and convenient, which is very popular among users. This type of packaging bag can be used to package various products, such as books, clothing, industrial parts, toys, etc., especially for the packaging of frequently opened and closed candies, cooked foods, and various small foods. It is very convenient, clean, hygienic, and convenient to store.
(1) The selection of raw materials for the production of extruded polyethylene self sealing films should use packaging grade blow molded PE resin. Generally, high-density polyethylene and low-density polyethylene resins can be used, and the melt flow rate MFR of the resin is required to be 2-7g/10min. At present, low-density polyethylene resin is still widely used, such as ZF7B resin produced by Sinopec Beijing Yanshan Petrochemical Co., Ltd., which can produce self sealing films.
(2) The production method of polyethylene self sealing film is extrusion blow molding, which can be produced by extrusion flat blowing method and extrusion top blowing method. The production process sequence is exactly the same as that of ordinary polyethylene extrusion blown film production.
(3) PE universal single screw extruder, the screw diameter is selected according to the bending diameter of the extruded blow molded self sealing film, generally using 45mm and $65mm; The length to diameter ratio L/D is greater than 20:1, the compression ratio is 3, and the mesh size and installation position of the porous plate three-layer filter screen are 801
100/80 mesh. The forming mold adopts a spiral structure with a core rod. In addition to a buffer groove, the straight section of the discharge port is also equipped with convex edges and groove type material limiting structures that can form a self sealing film anchor section.
