HDPE twisted film: Unidirectionally stretched HDPE twisted film has the advantages of high strength, high gloss, high transparency, etc. and a total of almost kink properties comparable to cellophane. It is widely used in candy packaging and the price is much lower than cellophane. There are two methods for producing a uniaxial tensioned HDPE twisted film: one is an extrusion casting method and the other is an extrusion film blowing method.
An example of a factory HDPE twist film is as follows. The extruder screw is a twin-screw mixing screw with a diameter of 65 mm and an aspect ratio of 26:1. The machine head is a spiral center feed head with a die diameter of 300 mm and a clearance of 2.8 mm. The extrusion volume is 70 kg/h. The process flow chart shows that the raw material for the production of HDPE Daqing, the brand name is PE-LALH-50D012, MFR is 1.0g/10 min.
The temperature control of the fuselage and the head adopts a balanced temperature, ie, the temperature changes from the feed to the head is small. The specific temperature is shown in the table. Body and head temperature data: feeding section: 170°C; melting front section: 180°C, rear section 200°C; metering front section: 215°C, rear section: 215°C; machine neck: 205°C; die: 205°C; The screw speed is controlled at 30 - 35 r/min. In the process flow chart, there are a total of 11 rollers after the extension roller, in which 4 rollers in the I zone are preheating rollers, 2 rollers in the zone II are stretching rollers, and 2 rollers in the pan area are the shaping rollers. The barrel, one in the N zone is a heat treatment roller, and the two rollers in the V zone are the shaping rollers.
Roller temperature and roll speed in the preheat zone (zone I) are shown in the table.
The temperature and speed values of each roller in zone I
│ serial numbers │1 -1 │1-2 │1-3 │1-4 │
│Roll temperature/°C │80-85│90 │100 │102 │
│Roll speed/(r/min)│6 │6 │ 6 │6 │
The draw ratio was controlled between 5.0--7.0 and the HDPE twisted film was QB 1128-91.