Production technology of polyvinyl chloride (PVC) heat shrinkable film

PVC heat shrinkable film the general situation of PVC heat shrinkable film is one of the heat shrinkable film application development earlier, has widely used in the packaging of goods, although it have strong pressure from environmental protection in recent years and polyolefin heat shrinkable film ( pofc3) The huge challenge, but is still a large number of production, application, PVC shrink film is firmly holding many traditional applications. In principle can be applied to the following process any of the production of PVC heat shrinkable film. Blow molding in the production of PVC heat shrinkable film blow molding technology has a direct blow molding and secondary blowing ( Double bubble) Method two kinds. Rolling method through three rollers or four roll calender rolling into thick film ( Grey film) , and then to preheating, transverse tensile and longitudinal tensile ( Or only in the horizontal or only in the longitudinal tensile) Heat shrinkable film, cooling system. Extrusion LiuYanFa LiuYanFa thick film production (first Grey film) And heating, transverse tensile and longitudinal tensile ( Or only in the horizontal or only in the longitudinal tensile) Heat shrinkable film, cooling system. In the actual production, in order to reduce the production cost, sex was a good film, in addition to individual circumstances, almost without exception, usually manufactured blown film, after boiling water heating method for secondary blowing stretching, packaging production PVC heat shrinkable film. Namely, in accordance with the proposed formula, after weighing various components, via high speed mixer mixing with extruder extrusion granulation ( Extruding temperature control in the 170 - Between 185 ° C) ; Out of the compound was grain blowing thick film ( 180 - 190°(C) , and then heated to 95 - after cooling 100°C( Commonly used boiling water heating) And the second huff and rapid traction for PVC heat shrinkable film; When extrusion machine has excellent plasticizing effect, can remove granulation process, direct use of uniform mixing heat shrinkable film, powder material production to reduce production costs. If it's not boiling water heating, to stay in thick film, PVC extrusion cooling to 90 - After 120 ° C, directly to the secondary blowing ( Vertical and lateral blowing rapid traction) , also can get PVC heat shrinkable film, but this method is using secondary heating, secondary blowing method, control of process conditions are difficult, the quality of the product stability is often not as good as the secondary heating, secondary blowing products, therefore, in the production of PVC heat shrinkable film, the less this method.