Talking about the production process and production process of soft PVC blown film

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What is the production process and production process of soft PVC blown film?

(1)Production process. The production process of soft pvc blown film is as follows.

There are two kinds of production processes of PVC blown film. One is to use powder direct extrusion blow molding, and this method can only be plasticized well by using an extruder with large aspect ratio; Another method is to use a common extrusion film blowing unit and blow film with pellets. Although granulation process is added, the extruder structure is relatively simple. Most domestic manufacturers adopt this method.

(2)Production process.

① ingredients. In order to remove impurities from the material, PVC resin needs to pass 15. 7 mesh/cm (40 mesh)Screen, plasticizer through 39. 4 Mesh/cm (100 mesh) Copper wire mesh and other additives are diluted with plasticizer and ground with a three-roll grinder, with fineness below 80um. Then, according to the formula, the kneading machine is placed, and the kneading temperature is 100- 120 ° C, when the material is loose and elastic, it can be discharged. The kneaded materials are put into an extrusion granulator for granulation, and the granulation temperature should not be too high, generally controlled at 150 ~ At 170 ℃, the particles of the extruder should be neat, plasticized well and not adhered.

② extrude and blow the film. In order to ensure the quality of the blown film, it is best to use hot particles. On the one hand film plasticizing good on the other hand also can reduce blown film of energy consumption. In order to reduce the causePaste the car' The number of times the head is disassembled, the head temperature should be lower than the body temperature. The specific process conditions are as follows: the temperature of the rear section of the extruder is 150 ~ 160 ℃, middle temperature 170- 180 ℃, front temperature 170-180 ° C, the head temperature is about 170 ° C. The inflation ratio is usually (1. 5 ~ 2. 5): 1. The blown film should be well cooled, otherwise the film will stick.