Hot fill container and closure and associated method
A method for hot-filling and closing a polymer container is disclosed in which one of the closure for the container and the head space area of the container is provided with a hole covered with a hydrophobic air permeable membrane. The container is then filled with a hot liquid and the filled container is closed but for the air permeable component. The filled container is then cooled with the pressure between the interior of the container and the ambient pressure being equalized due to the air permeable membrane. Subsequent to cooling, an air-tight seal is provided over the membrane-covered hole. An associated container and closure cap is also disclosed.
1. A method comprising:
providing a polymer container comprising a container body, a closure configured for capping the body, at least one of the closure and body having a through-going hole opening at inner and outer ends thereof into respective inner and outer surfaces of the at least one of the closure and body, and a hydrophobic air permeable membrane secured to the inner surface and closing the inner end of the hole;
filling the container with a hot liquid;
applying the closure to the filled container;
allowing the filled container and the liquid to cool, wherein air can pass through the membrane during cooling to permit equalization between pressure on an interior of the container and ambient pressure; and
applying an air tight seal that completely covers the hole to close the outer end of the hole, after the container and the liquid have cooled and the pressure on the interior of the container has equalized with ambient pressure, to prevent further migration of air across the membrane.
2. The method of claim 1 wherein the seal comprises a dryable coating.
3. The method of claim 2 wherein the dryable coating comprises a UV activated sealant.
4. The method of claim 2 wherein the dryable coating comprises a paint.
5. The method of claim 2 wherein the air tight seal is permanently bonded to the at least one of the closure and the body, permanently closing the outer end of the hole, and wherein the seal completely covers the hole to close the outer end of the hole.
6. The method of claim 1 wherein the seal comprises a semi-transparent adhesive.
7. The method of claim 1 wherein the seal comprises an air tight membrane with a pressure-sensitive adhesive on one surface thereof.
8. The method of claim 1 wherein the seal comprises a composition which solidifies upon exposure to actinic radiation.
9. The method of claim 1 wherein the hydrophobic air permeable membrane comprises a material selected from a group consisting of: expanded polytetraflouro-ethylene and polypropylene.
10. The method of claim 1 wherein the air tight seal extends from the air permeable membrane within the hole and terminates flush with the outer surface of the at least one of the closure and body.
11. The method of claim 1 wherein the air tight seal extends atop the outer surface of the at least one of the closure and body and covers the outer end of the hole.
12. The method of claim 1 wherein the air tight seal is permanently bonded to the at least one of the closure and the body, permanently closing the outer end of the hole, and wherein the seal completely covers the hole to close the outer end of the hole.
13. The method of claim 1 wherein the air tight seal is supported by the air permeable membrane and extends therefrom within the hole so as to terminate flush with the outer surface of the body.
14. The method of claim 13 wherein the air tight seal permanently closes the outer end of the hole.