Apparatus for producing injection-molded parts

Abstract

Apparatus for producing injection-molded parts, particularly PET preforms, includes a twin-screw extruder or multi-screw extruder for preparing and/or plasticizing material, preferably in granular form, which is transferred to a transfer reservoir. A piston unit further processes the material. The extruder has a plurality of processing zones, whereby at least two process zones are configured as degassing zones.

1 . Apparatus for producing an injection-molded part, comprising: 
 a twin-screw extruder for processing and/or plasticizing a material, said twin-screw extruder having processing zones, wherein at least two of the processing zones are implemented as a degassing zone;    a transfer reservoir for receiving processed and/or plasticized material; and    a piston unit for further processing the processed and/or plasticized material.    
   
   
       2 . The apparatus of  claim 1 , wherein the injection-molded part is a PET preform.  
   
   
       3 . The apparatus of  claim 1 , wherein the material has a granular form.  
   
   
       4 . The apparatus of  claim 1 , wherein the twin-screw extruder has five processing zones.  
   
   
       5 . The apparatus of  claim 1 , wherein one of the processing zones is constructed for processing and/or plasticizing material to produce a melt.  
   
   
       6 . The apparatus of  claim 5 , wherein the plurality of processing zones are placed sequentially to define a first processing and a last processing zone, with the first processing zone representing the one of the processing zones constructed for processing and/or plasticizing material.  
   
   
       7 . The apparatus of  claim 5 , wherein at least 90% of the material is melted in the one of the processing zones.  
   
   
       8 . The apparatus of  claim 6 , wherein a second and a fourth one of the processing zones are configured as a degassing zone.  
   
   
       9 . The apparatus of  claim 8 , wherein the degassing zone involves a decompression of the melt and exposure of the melt to a first vacuum of less than 5 mbar to extract H 2 O and decomposition products.  
   
   
       10 . The apparatus of  claim 1 , wherein at least one of the processing zones is configured as calming zone.  
   
   
       11 . The apparatus of  claim 6 , wherein a third one of the processing zones is configured as calming zone.  
   
   
       12 . The apparatus of  claim 5 , wherein one of the processing zones is configured to compress the melt.  
   
   
       13 . The apparatus of  claim 6 , wherein a fifth one of the processing zones is configured to compress the melt.  
   
   
       14 . The apparatus of  claim 1 , wherein the twin-screw extruder is starve fed.  
   
   
       15 . The apparatus of  claim 1 , wherein the twin-screw extruder is fed by a way of gravimetric metering.  
   
   
       16 . The apparatus of  claim 1 , wherein f the twin-screw extruder has two screws rotating in a same direction.  
   
   
       17 . The apparatus of  claim 1 , wherein the twin-screw extruder is constructed to operate with high torque at low rotation speed.  
   
   
       18 . The apparatus of  claim 1 , further comprising a feed unit for admixing an additive in at least one of the processing zones.  
   
   
       19 . An apparatus for producing an injection-molded part, comprising: 
 a multi-screw extruder for processing and/or plasticizing a material, said multi-screw extruder having processing zones;    a feed unit for admixing an additive in at least one of the processing zones;    a transfer reservoir for receiving the processed and/or plasticized material; and    a device for further processing the material.    
   
   
       20 . The apparatus of  claim 19 , wherein one of the processing zones is configured as a degassing zone.  
   
   
       21 . The apparatus of  claim 19 , wherein at least two of the processing zones are configured as degassing zones.  
   
   
       22 . The apparatus of  claim 19 , wherein the feed unit is constructed to admix an additive for attaining barrier characteristics of the material.  
   
   
       23 . The apparatus of  claim 19 , wherein the injection-molded part is a PET preform.