PVC extrusion blown film production process

日期:2019/8/15 9:03:23 / 阅读: / 来源:本站

PVC extrusion blown film production, due to different cooling and heating methods, the following process can be subdivided
1) Flat blowing (water cooling) flat expansion hot water bath process. PVC compounding → extrusion plasticizing → horizontal extrusion of tube blank → tube blanking → thick film water shower cooling → drafting → hot water bath heating → thick film inflation → cold water jacket cooling → drafting → coiling.
The process flow is suitable for producing a heat shrinkable film having a small width, such as a shrink sleeve. The entire production unit can be mounted on the same plane.
2) Lower blowing (water cooling) process of expanding the hot air. PVC compounding → extrusion plasticization → extrusion of tube blank → tube blank inflation → thick film water shower cooling → drafting → hot air oven heating → drafting → thick film inflation → cold water jacket cooling → drafting → volume take.
The process is suitable for producing heat shrinkable film for packaging. The extruder of the production line needs to be placed on a high-end platform. The electric hot air oven heating device can be placed under the thick film inflation device or above the thick film inflation device. The hot air oven can also be replaced with a hot water bath.
3) The upper blowing (air-cooled) swell hot water bath process. PVC compounding → extrusion plasticization → extrusion
Tube blank → tube blank inflation → thick film air cooling → drafting → hot water bath heating → thick film inflation → cold water jacket cooling → drafting → coiling.
The upper blowing process is a common process of PVC heat shrinkable film, Figure 56 shows
Schematic diagram of the production equipment, Table 5-9 lists the main technical parameters of the typical production equipment, which can be used to produce PVC heat shrinkable printing labels and industrial packaging films. PVC heat shrinkable film production equipment, the extruder is generally washed with a tapered head isometric gradient screw, mandrel type angled die, if you choose a rotating mandrel right angle die (Figure 5-8), can make heat The shrink film is flatter and the thickness deviation distribution is more uniform.
The heating device before the secondary inflation of the film can use a hot water bath or an electric hot air oven. However, the water temperature of the hot water bath is convenient to control, and the maximum water temperature can be maintained at a constant temperature range of (98 ± 2) ° C. The film is evenly heated, which is more conducive to the stretching of the PVC film.
When the PVC heat shrinkable film is produced, the film which is cooled and wound still produces post-shrinkage phenomenon. Therefore, the shrink film after winding should be placed at room temperature for more than 24 hours before cutting and printing.

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