Hollow containers having a very thin inert or impermeable inner surface layer by coating the inside surface of the preform
AssigneeThe Coca-Cola Company
InventorGeorge Plester
Life of this patent
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Abstract
A very thin inner layer composed of a polymer chosen for its barrier and/or inertness properties is fabricated within a container preform constructed mainly from another polymer, or a structure of polymers. The inner layer on the preform is produced either by a controlled coating method involving coating of the injection mold core rod prior to injection molding or by a coating applied directly to the preform after injection molding. This enables both inner and main layers to be brought together at a time when the interface between them is molten. A tie layer can be employed, when desirable, to enable the layers to be combined without melting the layer interface.
Claims3
A method of fabricating an inner layer of a first polymer within a stretch blown container preform consisting of a second polymer, comprising the steps of:
- (a) heating a molding core rod;
- (b) rotating a coating depositor having a depositing slot therein around the core rod, and depositing thereon an inner layer of a first polymer while being in a molten state, said first polymer having predetermined barrier and/or inertness characteristic;
- (c) removing the depositor from the proximity of the core rod with the inner layer formed thereon;
- (d) inserting the core rod into an injection cavity mold;
- (e) cooling the core rod;
- and
- (f) feeding a second polymer into the injection mold and flowing the second polymer over the inner layer of said first polymer while the inner layer is still molten to form a preform having an inner layer of barrier material.
Dependencies are inferred from the claim text.