Patent ID: 8556621
Filing Date: 2013-10-15
Classification: B29C,B29K

Abstract:
1. An extrusion blowmolding apparatus for preparing articles from a thermoplastic polyester material, the apparatus comprising: an extrusion die having an upstream portion for receiving the thermoplastic polyester material and a downstream portion having a die head through which molten thermoplastic polyester material is flowed to form a parison suitable for extrusion blowmolding; wherein the extrusion die has extending therethrough a generally cylindrical barrel having a length to diameter (L/D) ratio of from about 20:1 to about 40:1, and an extrusion screw disposed within the barrel, wherein the extrusion screw comprises a shaft and a spiral flight extending radially from the screw shaft along at least a portion of the length of the shaft defining a feed section, a primary section, a secondary section, and a metering section, wherein the flight has an outer edge in sliding contact with an inner surface of the barrel; and wherein the cylindrical barrel has a radius R and the shaft has a radius S which satisfy the following relationship: