Methods and apparatus for depositing barrier coatings
AssigneePolar Materials, Inc.
InventorsH. Ronald Thomas, Robert J. Babacz, Robert R. Newton
Life of this patent
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Abstract
A barrier coating is formed on a polymeric article, such as on the interior of a thermoplastic container. An oxidizing gas is converted to a plasma in a plasma chamber remote from the treatment chamber. The resulting plasma-activated oxidizing species are delivered to the interior of the container. An organosilicon reactant vapor is separately but simultaneously delivered to the interior of the container so that the organosilicon vapor and oxidizing active species mix within the container. An electric field is also applied to the container, so that the reaction products are deposited under the influence of the electrical field to form the barrier coating.
Claims21
A method of forming a barrier coating on a polymeric article comprising the steps of:
- (a) passing an oxidizing gas in a downstream direction through a plasma zone remote from said article and converting said oxidizing gas to a plasma in said plasma zone so that said plasma forms activated oxidizing gas species as it passes downstream from said plasma zone;
- (b) delivering said activated species to the vicinity of said article;
- (c) delivering an organosilicon vapor to the vicinity of said article separately from said activated species;
- (d) mixing said organosilicon vapor with said activated species in proximity to said article so that said organosilicon vapor reacts with said activated species while maintaining said mixed activates species and organosilicon vapor under subatmospheric pressure;
- and
- (e) applying an alternating electrical potential of about 10 v to about 5 Kv at a frequency between about 1 KHz and about 100 MHz, and at a power input of between about 0.05 watts/cm.sup.2 and about 10.0 watts/cm.sup.2 of article surface area to said mixed activated species and organosilicon vapor in proximity to said article so that reaction products formed from said mixed activated species and organosilicon vapor are deposited on said article under the influence of said alternating electrical potential and so that said deposited reaction products form a barrier coating on said polymeric article while maintaining said polymeric article at a temperature below the heat distortion temperature of the polymeric article, said barrier coating having at least one of i) permeance of oxygen of less than about 0.20 cc O.sub.2 /100 in.sup.2 -day-atm, ii) permeance of carbon dioxide of less than 1.0 cc CO.sub.2 /100 in.sup.2 -day-atm, or iii) permeance of water of less than 0.4 gm H.sub.2 O/100 in.sup.2 -day-atm.
Dependencies are inferred from the claim text.