Thermoplastic containers manufactured by extrusion blow molding apparatus

Abstract

Extrusion blow molding apparatus ( 10 ) having a blow mold ( 12 ), a neck mold ( 14 ) positioned above the blow mold and an anvil ( 30 ) positioned in an outwardly facing cavity ( 32 ) of the neck mold. A container (C) is produced in the molding apparatus from a parison of a heated thermoplastic material by introducing pressurized blowing fluid into the container being formed by way of a blow pin assembly ( 16 ) that is reciprocable relative to the blow mold. The blow pin assembly has an inner tubular member ( 20 ) with a free end that is within the container during blowing, and an outer tubular member ( 22 ) that surrounds the inner tubular member and defines an annulus therewith for withdrawing spent blowing fluid from the container. The outer tubular member has radial ports ( 24 ) for directing spent blowing fluid against a moil (M) being formed at a rim (R) of a finish (F) of the container. A restricted outlet from the finish of the container is obtained by providing the anvil with an inwardly and downwardly directed nose portion ( 34 ) to form a restricted annular portion (P) in the finish at a location below the rim.

What is claimed is:  
     
         1 . A container having a body portion and a finish portion formed integrally with said body portion, said container being formed from an extruded parison of a thermoplastic material in blow molding apparatus in which said body portion is formed from a portion of the parison in a blow mold of the blow mold apparatus and the finish is formed from another portion of the parison in a neck mold, said finish portion having an annular partition extending across said finish portion at a location positioned within said finish portion at an elevation below a rim of said finish portion, said annular partition having an internal diameter that is substantially smaller than any other internal diameter of said finish portion  
     
     
         2 . A container according to    claim 1    in which said blow molding apparatus is apparatus of the extrusion blow molding type.  
     
     
         3 . A container according to    claim 2    in which the container is produced from a melt of polypropylene or high density polyethylene.  
     
     
         4 . A container according to    claim 1    wherein the internal diameter of said annular partition is the “C” dimension of the finish portion of the container.