Method of injection molding PVC products
OwnerHenricus G. M. Lomaninventor
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Abstract
The present disclosure is directed to a method of injection molding PVC products from powdered raw material, while employing an injection molding machine having a plasticizing unit having a rotary screw and a rotary screw and an injection unit having a screw which both rotates and reciprocates. The powdered raw material is subjected firstly to a prejellifying treatment during forced transportation through the plasticizing unit in which it is heated and brought to agglomerate in a relatively short time and the agglomerate is subjected to a vacuum after the prejellifying treatment and its introduction into the injection unit at an absolute pressure of less than 50 kPa.
Claims3
The method of injection molding PVC products from powdered raw material while employing an injection molding machine of a two stage cascade type having an upper plasticizing double screw extruder and a lower injection apparatus having one injection screw, wherein the raw material is subjected to a prejellifying treatment during forced transportation of the powdered raw material through the upper plasticizing screw extruder unit in which it is heated and brought to an agglomerated state in a relatively short time, subjecting the plasticized material to a vacuum while passing through the lower injection unit.
Dependencies are inferred from the claim text.