Method for the preparation of hollow plastic articles

Claim 1

A method for the preparation of oriented hollow articles of moldable organic plastic material which comprises: providing an organic plastic parison in a formable condition at a temperature substantially above that required for orientation of said plastic on a temperature controlled first core in a temperature controlled first mold, said first core and first mold being held at temperatures substantially below that required for orientation of said plastic; altering the heat content of said parison by means of heat exchange with said first core and first mold to result substantially in the heat content of said parison having an average temperature suited for orientation, wherein said alterning is effected at temperature gradients adapted for rapid heat flow, with an unequal distribution of temperature resulting across the walls of said parison; providing a first means to retain the parison in a closed environment efficiently suitable for equalizing the temperature distribution within the walls of the parison to attain a temperature substantially corresponding to the orientation temperature of said plastic; providing a second means capable of influencing the inside temperature of said parison; transferring said parison from said first core and first mold to said second means and first means; maintaining said parison on said second means in said first means without substantially altering the heat content of said parison for a time sufficient for the portions of said parison previously in contact with said first core and first mold to substantially reach the orientation temperature of said plastic and to substantially equalize the temperature distribution of said parison; transferring said parison to a blow mold; and fully expanding the parison in said blow mold.

Claim 2

A method for the preparation of oriented hollow articles of moldable organic plastic material which comprises: providing an organic plastic parison in a formable condition at a temperature substantially above that required for orientation of said plastic on a temperature controlled first core in a temperature controlled first mold, said first core and first mold being held at temperatures substantially below that required for orientation of said plastic; altering the heat content of said parison by means of heat exchange with said first core and first mold to result substantially in the heat content of said parison having an average temperature suited for orientation, wherein said alterning is effected at temperature gradients adapted for rapid heat flow, with an unequal distribution of temperature resulting across the walls of said parison; providing a first means to retain the parison in a closed environment efficiently suitable for equalizing the temperature distribution within the walls of the parison to attain a temperature substantially corresponding to the orientation temperature of said plastic; providing a second means capable of influencing the inside temperature of said parison; transferring said parison from said first core and first mold to said second means and first means; maintaining said parison on said second means in said first means without substantially altering the heat content of said parison for a time sufficient for the portions of said parison previously in contact with said first core and first mold to substantially reach the orientation temperature of said plastic and to substantially equalize the temperature distribution of said parison; transferring said parison to a blow mold; and fully expanding the parison in said blow mold.

Claim 15

A method for the preparation of hollow articles of moldable organic plastic material which comprises: providing an organic plastic parison in a formable condition on a temperature controlled first core in a temperature controlled first mold; altering the heat content of said parison by means of heat exchange with said first core and first mold to result substantially in the heat content of said parison having an average temperature suited for orientation, wherein said altering is effected at temperature gradients adapted for rapid heat flow, with an unequal distribution of temperature resulting across the walls of said parison; locating said first core bearing said parison in a temperature controlled second mold; pre-forming said parison within said second mold to separate said parison from said first core and conform said parison to the shape of said second mold and to have an inside configuration shaped to permit insertion of a second core therein in substantially full contact therewith; retaining said pre-formed parison within said second mold while separating said first core and second mold from each other; providing a temperature controlled second core having an external configuration shaped to conform to the internal configuration of said pre-formed parison; inserting said second core in said pre-formed parison contained within said second mold; substantially equalizing the temperature distribution of said parison that has been brought about by said temperature gradients by heat exchange with said second mold and second core; transferring said parison to a blow mold; and fully expanding the parison in said blow mold.

Claim 16

A method for the preparation of hollow articles of moldable organic plastic material which comprises: providing an organic plastic parison in a formable condition on a temperature controlled first core in a temperature controlled first mold; altering the heat content of said parison by means of heat exchange with said first core and first mold to result substantially in the heat content of said parison having an average temperature suited for orientation, wherein said altering is effected at temperature gradients adapted for rapid heat flow, with an unequal distribution of temperature resulting across the walls of said parison; locating said first core bearing said parison in a temperature controlled second mold; pre-forming said parison within said second mold to separate said parison from said first core and conform said parison to the shape of said second mold and to have an inside configuration shaped to permit insertion of a second core therein in substantially full contact therewith; retaining said pre-formed parison within said second mold while separating said first core and second mold from each other; providing a temperature controlled second core having an external configuration shaped to conform to the internal configuration of said pre-formed parison; inserting said second core in said pre-formed parison contained within said second mold; substantially equalizing the temperature distribution of said parison that has been brought about by said temperature gradients by heat exchange with said second mold and second core; transferring said parison to a blow mold; and fully expanding the parison in said blow mold.