Method of making partially crystalline biaxially oriented hollow plastic heat set containers

A method for making a partially crystalline, biaxially oriented heatset hollow plastic container from a hollow parison having an open end and a closed end comprising

• engaging the open end of a plastic parison which is at a temperature within its molecular orientation temperature range by a clamping and blow pin assembly,
• positioning a mold base in axial alignment with said engaged hot parison,
• enclosing a hot mold about the mold base, said mold being at heatsetting temperature,
• expanding said plastic parison within said hot mold and mold base by internal pressurization through the clamp and blow pin assembly to induce biaxial orientation of the plastic parisons force the plastic parison into intimate contact and conformance with the hot mold and to maintain contact by such internal pressurization between the mold and the biaxial oriented container for a time sufficient to induce partial crystallization in the biaxial oriented container,
• reducing the internal pressurization of the hot blown hollow container,
• thereafter opening the hot mold while maintaining engagement of the mold base with the base of the hot blown hollow container and the clamping and blow pin assembly with the open end of the hot blown hollow container, such as to prevent distortion of the base of the container by the internal pressurization when the hot mold is opened,
• maintaining a lower internal pressurization of the container to prevent significant shrinkage, and
• transferring the biaxially oriented hot container to a position adjacent an open cold mold which is at a temperature substantially less than the temperature of the hot mold by relatively moving the mold base and the clamping and pin assembly from a position adjacent the open hot mold to a position adjacent the open cold mold while maintaining the reduced internal pressurization at least sufficient to prevent shrinkage, and maintaining engagement of the mold base with the base of the hot blown container to prevent distortion or tilting of the container relative to said open end of the container during relative movement,
• enclosing the container in the cold mold by closing the cold mold about the mold base and the clamping and blow pin assembly which are in engagement with the hot blown container,
• holding the container against the confines of the cold mold by maintaining internal pressurization for a time sufficient to prevent shrinkage,
• exhausting the pressure from the container,
• opening the cold mold,
• removing the container, and
• moving the mold base and the clamping and blowing pin assembly relative to the hot mold and cold mold to bring the mold base and clamping and blow pin assembly into position adjacent the hot mold.

A method for making a partially crystalline, biaxially oriented heatset hollow plastic container from a hollow parison having an open end and a closed end comprising

• heating a hot plastic parison at a conditioning station to a temperature within its molecular orientation temperture,
• transferring said hot parison to a position adjacent a hot mold at a blowing and heatsetting station,
• engaging the open end of a plastic parison which is at a temperature within its molecular orientation temperature range by a clamping and blow pin assembly,
• positioning a mold base in axial alignment with said engaged hot parison,
• enclosing a hot mold about the mold base, said mold being at heatsetting temperature,
• expanding said plastic parison within said hot mold and mold base by internal pressurization through the clamp and blow pin assembly to induce biaxial orientation of the plastic parison, force the plastic parison into intimate contact and conformance with the hot mold and to maintain contact by such internal pressurization between the mold and the biaxial oriented container for a time sufficient to induce partial crystallization in the biaxial oriented container,
• reducing the internal pressurization of the container,
• thereafter opening the hot mold while maintaining engagement of the mold base with the base of the hot blown hollow container and maintaining engagement of the clamping and blow pin assembly with the open end of the hot blown hollow container such as to prevent distortion of the base of the container by the internal pressurization when the hot mold is opened,
• maintaining a lower internal pressurization of the container to prevent significant shrinkage, and
• transferring the biaxially oriented container to a position adjacent an open cold mold at a cooling station, by relatively moving the mold base and clamping and pin assembly from a position adjacent the open hot mold to the position adjacent the open end mold while maintaining the reduced internal pressurization at least sufficient to prevent shrinkage, said cold mold being at a temperature substantially less than the temperature of the hot mold and maintaining engagement of the mold base with the base of the hot blown container to prevent distortion or tilting of the container relative to said open end of the container during the relative movement,
• enclosing the container in the cold mold by closing the cold mold about the mold base and clamping and blow pin assembly which are in engagement with the hot blown container,
• holding the container against the confines of the cold mold by maintaining internal pressurization for a time sufficient to prevent shrinkage,
• exhausting the pressure from the container,
• opening the cold mold,
• removing the container, and
• moving the mold base and clamping pin assembly relative to the hot mold and cold mold to bring the mold base and clamp pin assembly into position adjacent the hot mold.