Method for processing parisons

Claim 1

In a method for temperature conditioning an organic plastic parison for the operation of multi-axial orientation such as by stretching and expanding, the improvement which comprises: providing said parison at an elevated temperature above that required for orientation of said plastic; retaining and cooling said parison in a first mold assembly which includes a first mold, a mold cavity, a neck mold and a core, wherein said first mold and first core are maintained at temperatures below that required for orientation, but said first mold is maintained at a lower temperature than said core to assure rapid removal of heat from said parison; separating said core from said parison while retaining and cooling said parison in said first mold wherein separation of said parison and said core is effected by applying positive fluid pressure inside said parison while said separation of the core is taking place and thereby facilitating removal of the core from the parison and avoiding the formation of a vacuum inside the parison during said separation; separating said parison and said first mold from each other after a substantial change in the heat content of said parison will have taken place, wherein the heat content of said parison is altered by means of heat exchange with said core and mold to result substantially in the heat content of the parison having an average temperature suited for orientation, wherein said altering is effected at temperature gradients adapted for rapid heat flow and with an unequal distribution of temperature resulting across the walls of the parison; and locating the parison in an environment capable of influencing the cross-sectional temperature distribution in the walls of said parison, with said locating facilitated by said neck mold, wherein the temperature of the outside surface of said parison is lower than the temperature of its inside surface at the time said parison is located in said environment, and equalizing the temperature distribution of the parison in said environment without substantially altering the heat content of said parison to attain a temperature substantially corresponding to the orientation temperature.