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US 3,944,645 AGranted
Method for balloon blown plastic molding
AssigneeFarrell Patent Company
InventorJohn J. Farrell
Life of this patent
Estimating the term…
Abstract
This invention is a method of making blown plastic articles on an injection blow molding machine with an expandible balloon that covers the core rods and over which a parison is applied at an injection mold station. The parison can be blown at lower temperatures for better orientation; and the balloon permits circulation of cooling fluid, including liquid, to cool the blown article from the inside while contact with the blow mold cavity cools the blown article from the outside.
Claims10
A method for injection blow molding a biaxially oriented hollow plastic article comprising:
- providing a core rod with a deflated balloon surrounding the core rod, and maintaining a fluid tight seal between the core rod and balloon adjacent the neck portion of the parison, injection molding plastic material onto the exterior surface of the balloon to form a parison;
- conditioning the parison to a temperature low enough to permit orientation;
- inflating the core rod supported balloon in a blow mold so as to stretch the parison both circumfrentially and axially to take the shape of the blow mold so as to form a biaxially oriented article;
- providing a clearance between the expanded balloon and the core rod adjacent the neck portion of the blown article for permitting the balloon to collapse;
- and collapsing the balloon by drawing vacuum on the balloon through the core rod to provide a clearance between the balloon and the inside surface of the blown article, and permitting air to enter this clearance so as to collapse the balloon.
2 more elements
Dependencies are inferred from the claim text.