Method of manufacturing a plastic container
View Patent ↗Forming a plastic container having a base portion adapted to support the container, a cylindrical sidewall projecting upwardly from the base, and a neck finish projecting upwardly from the sidewall and having an opening to the inside of the container. The container is formed with a molded outer layer with inner and outer surfaces and an inner layer extending over the inner surface of the sidewall and base, with the neck finish free from the inner layer. The outer layer is formed with at least one oxygen scavenger material that reacts with oxygen, and the inner layer includes at least one oxygen barrier material.
1. A method which comprises:
forming a plastic container having a base portion adapted to support the container, a cylindrical sidewall projecting upwardly from said base portion, and a neck finish projecting upwardly from said cylindrical sidewall and having an opening to the inside of the container, wherein said container includes a molded outer layer having an inner surface and an outer surface, where said outer layer extends over the base portion, cylindrical sidewall and neck finish of said container; and
forming an inner layer over the inner surface of the outer layer, wherein the neck finish is free from the inner layer, including the steps of providing that the outer layer contains at least one oxygen scavenger that reacts with oxygen, and that the inner layer includes at least one barrier material, wherein the neck finish is free from the barrier material included in the inner layer, and including providing that the outer layer has a thickness of from 6 to 23 mils, and the inner layer has a thickness of from 0.5 to 10 microns.
2. The method of claim 1 , including the step of providing that the inner layer is a non-structural, amorphous carbon coating.
3. The method of claim 1 , including the steps of forming said container to include a shoulder portion which extends inwardly between the sidewall and the neck finish, and extending the inner layer at least in part over the shoulder portion.
4. The method of claim 2 including the steps of covering the inner surface of the outer layer at the neck finish, and forming said carbon coating on the inner surface of the container while the inner surface of the neck finish is covered, thereby leaving the neck finish free from carbon coating.
5. The method of claim 4 , including forming the inner layer with a vacuum nozzle which engages the neck finish of the container.
6. The method of claim 1 , including forming a blow molded container.
7. The method of claim 1 , including providing that the outer layer is a mono-layer plastic material.
8. The method of claim 1 , including providing that the outer layer is a multi-layer plastic material.
9. The method of claim 1 , including providing that the neck finish includes a threaded portion beneath the opening and an outwardly extending flange beneath the threaded portion.
10. The method of claim 1 , including providing that the base portion includes a circumferential encircling member and an indented center.
11. The method of claim 1 , including providing said container with a shoulder portion which extends inwardly between the sidewall and neck finish, wherein the inner layer extends at least in part over the shoulder portion.
12. The method of claim 1 , including providing that the oxygen scavenger contains polyolefin oligomer segments.
13. The method of claim 1 , including providing that the oxygen scavenger contains polybutadiene.
14. The method of claim 1 , including providing that the barrier material is an oxygen barrier.
15. The method of claim 1 , including providing a closure over the neck finish.
16. The method of claim 15 , including providing that the inside surface of the closure includes at least one oxygen scavenger that reacts with oxygen.