Methods for Plasma Treatment on a Can Component, Feedstock & Tooling

Abstract

Methods are disclosed for applying a protective layer to a can component and for modifying surface properties of a can component, feedstock or tooling. An example method involves: (a) directing a precursor plasma plume at a surface of a can component via at least one precursor plasma gun, where the precursor plasma plume includes an ionized gas and an ionized precursor and (b) treating at least a portion of the surface of the can component with the precursor plasma plume and thereby forming a first layer on the portion of the surface of the can component treated with the precursor plasma plume.

Description

BACKGROUND

[0001] Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.

[0002] Many beverages contain diary which require pasteurization to slow spoilage caused by microbial growth. Milk or milk based products may be packaged, pasteurized and distributed in cans. For example, after filling cans with milk, the milk may be pasteurized at about 260.degree. F. for about 30 minutes. As such, if the can is not coated prior to being filled with milk, pasteurization may cause the bottom of the can to darken. To avoid this discoloration, a retort process may be used to coat the can bottoms. During a rinse stage of the retort process, the cans may be rinsed in washer water that includes zirconium phosphate. However, using too much zirconium phosphate may result in peeling of the lithography and using too little zirconium phosphate may result in the can bottoms turning brown. In addition, the washer fluids have to be drained on the back end after the rinse process completes, which may be labor and time intensive. On the front end, the zirconium phosphate solution has to be heated to a certain temperature for the coating process to be effective, which may cause delays in the coating process. Still further, the zirconium phosphate coating should not be applied to the neck area to avoid the lithography flaking in the neck area and this may be difficult to achieve during the rinse process.

SUMMARY

[0003] Example embodiments beneficially provide methods for applying a protective layer to a can component and/or for modifying surface properties of a can component. More specifically, example embodiments may generally relate to a precursor plasma plume that includes an ionized gas and an ionized precursor that may treat a beverage can component and form a layer on the surface of the can component. This layer may advantageously protect the can component from various environmental effects, for example, browning during the retort process or moisture and salty air encountered during transport that could cause corrosion, among other possibilities. In a further embodiment, this layer may have the benefit of being energy-adjusting in nature.

[0004] In addition, the can making process has been improved so that all can components may be made efficiently and at relatively low cost. Much of this efficiency may be attributed to the ability to cut, draw, iron, form, and trim at exceptionally high speed with minimal variation. However, in order to increase speed, friction forces should be minimized to limit heat, wear, and variation, for example, within the fabrication process. Thus, the ability to add a tightly bound, anti-friction layer significantly reduces heat and part wear within many locations in the can and end manufacturing process.

[0005] Other example embodiments, may generally relate to a precursor-free plasma plume that includes an ionized gas that may treat a beverage can component and change the surface properties thereof. Altering the surface properties of the beverage can component may advantageously include, for example, (i) adjusting the surface energy to promote even wetting or dewetting of ink, lube, water or other secondary materials, (ii) adding functional groups to the surface to promote laydown of ink through improved wetting, (iii) aid in removing contaminants from the surface by improved lubricant wetting of a metal surface, and/or adjusting can component surface energies that may aid in directing or distributing secondary materials to targeted zones on the surface of the beverage can component, (iv) dewetting to create specialized textures of ink and/or varnish, (v) dewetting to promote sheeting of washing or rinsing to prevent residual contaminants during drying, among other possibilities.

[0006] Other example embodiments, may generally relate to a precursor plasma plume or a precursor-free plasma plume that may treat a beverage can component and alter the surface properties of the beverage can component. This may have one or more beneficial effects, including (i) aiding in preferential bonding of applied materials, (ii) adding functional groups to the surface to improve bonding to ink, for example, (iii) adding a precursor coating to aid in adhesion of liners, such as compound sealant in a seam, for example, or adding a function coating to aid in adhesion of a liner of can component such as CapCan cap, among other possibilities.

[0007] In addition, the precursor plasma plume and the precursor-free plasma plume may beneficially be applied via one or more plasma guns that may have a controllable footprint to aid in precise treatment applications. For example, the plasma plumes may be directed at a can component such that the plasma treatment and any resulting protective layer or altered surface properties remain on the targeted surface of the can. In addition, a plasma gun may be beneficially used to administer plasma to a specific feature of a can component, such as a score of a can end, by tracing the score with the plasma plume of the plasma gun. In addition, the precursor layer may be created to protect exposed areas of a can component that has been created by other mechanical or high energy means such as stamping or laser etching of features. Plasma also has the added benefit of remaining close to room temperature and therefore may not heat up the can components, permitting easier handling of the can components during the manufacturing process. Plasma coatings may also be subjected to high temperatures from ovens without compromising the integrity of the coating. Lastly, plasma treatment may permit the use of an alkaline washer and eliminate the need for hydrofluoric acid washes used with the zirconium phosphate retort treatment that may pose a health hazard.

[0008] Thus, in one aspect, a method for applying a protective layer to a can component is provided including the features of (a) directing a precursor plasma plume at a surface of a can component via at least one precursor plasma gun, where the precursor plasma plume includes an ionized gas and an ionized precursor and (b) treating at least a portion of the surface of the can component with the precursor plasma plume and thereby forming a first layer on the portion of the surface of the can component treated with the precursor plasma plume.

[0009] In a second aspect, a method for modifying surface properties of a can component is provided including the steps of (a) directing a precursor-free plasma plume at a surface of a can component via at least one precursor-free plasma gun, where the precursor-free plasma plume comprises an ionized gas, wherein the surface of the can component is contoured or has a score and (b) treating at least a portion of the surface of the can component with the precursor-free plasma plume.

[0010] In a third aspect, a method is provided including the steps of (a) directing a precursor plasma plume at a surface of at least one of a can component, feedstock and tooling via at least one precursor plasma gun, where the precursor plasma plume comprises an ionized gas and an ionized precursor and (b) treating at least a portion of the surface of the at least one of the can component, the feedstock and the tooling with the precursor plasma plume and thereby forming a first layer on the portion of the surface of the at least one of the can component, the feedstock and the tooling treated with the precursor plasma plume.

[0011] In a fourth aspect, a method is provided including the steps of (a) directing a precursor-free plasma plume at a surface of at least one of a can component, feedstock and tooling via at least one precursor-free plasma gun, wherein the precursor-free plasma plume comprises an ionized gas, wherein the surface of at least one of the can component, the feedstock and the tooling is contoured or has a score and (b) treating at least a portion of the surface of the can component, the feedstock and the tooling with the precursor-free plasma plume.

[0012] These as well as other aspects, advantages, and alternatives, will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 is side view of a can body, according to one example embodiment.

[0014] FIG. 2 is a top view of can end, according to one example embodiment.

[0015] FIG. 3 is a cross-sectional view of a plasma gun known in the art, according to one example embodiment, that is configured to emit a plasma plume.

[0016] FIG. 4 is a flow chart of a method according to one example embodiment for forming a layer on a can component.

[0017] FIG. 5 is a flow chart of a method according to one example embodiment for changing surface properties on a can component.

DETAILED DESCRIPTION

[0018] Example methods for applying a protective layer to a can component and/or for modifying surface properties of a can component are described herein. Any example embodiment or feature described herein is not necessarily to be construed as preferred or advantageous over other embodiments or features. The example embodiments described herein are not meant to be limiting. It will be readily understood that certain aspects of the disclosed apparatus and methods can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein.

[0019] Furthermore, the particular arrangements shown in the Figures should not be viewed as limiting. It should be understood that other embodiments may include more or less of each element shown in a given Figure. Further, some of the illustrated elements may be combined or omitted. Yet further, an example embodiment may include elements that are not illustrated in the Figures.

[0020] As used herein, "plasma" refers to a gas, which may include a precursor in some embodiments, that has been ionized and excited to a higher energy state using high frequency, high voltage radio frequency or other method capable of producing plasma, for example, such that the plasma may contain atoms, molecules, positive ions and electrons and negative ions together with un-ionized material. Ionization of the gas and/or precursor may be induced via application of heat, an electric field or an electromagnetic field.

[0021] As used herein, an "ionized gas" may include, but are not limited to, argon, oxygen, nitrogen, dry air, nitrous oxide, trifluoroethane, tetrafluoromethane, or mixtures thereof. These gases may or may not remain ionized throughout before reacting with an identical or different molecule or with the surface of a beverage can component.

[0022] As used herein, a "precursor" is a molecule of low molecular weight capable of being ionized and reacting with identical or different molecules of low molecular weight to form a layer on a surface. Example precursors may include, but are not limited to, monomers (including siloxane-based monomers, such as hexamethyldisiloxane ("HDMSO") or hexamethyldisilazane ("HMDSN")), tetraethyl orthosilicate ("TEOS"), substituted organic siloxanes, acrylates, fluorinated acrylates, trifluoroethylene, trifluoroethane, epoxies, ethylene oxides, ethylene glycols, carbonates, methanol, ethylene diamine, styrene, solubilized metals, fluorinated oligomers, saturated oligomers, or mixtures thereof. These precursors may take the form of a gas or an aerosolized liquid or solution.

[0023] As used herein, "about" means +/-5%.

[0024] As used herein, a "can component" refers to a can body that has sidewalls and a bottom, a metal can bottle, a can end, a dome that may be seamed to a can body, a cap that may be attached to a dome, or other metal container component. The can bodies may be subjected to a series of processing operations including one or more of a blank and draw into a shallow cup, a redraw and iron to lengthen the sidewalls, a trim of the open end of the cup, a wash and dry, an outside coat, an oven-heated dry of the outside coat, a printing operation on the outside coat, a rim coat of the bottom of the can, an oven-heated dry of any printing ink, an application of a protective spray on the inside of the can body, an oven cure of the protective spray, fluting of the sidewalls of the can body, forming of a neck and flange at the open end of the cup body or a longer neck and bottle finish, and/or reforming of the bottom surface into a dome, among other possibilities. The term "can body" may refer to the various forms of the cup during any one of the various processing operations. An example can body 100 that has been processed through the foregoing manufacturing steps is shown in FIG. 1. The can body 100 may have a neck 105 and a flange 110, as well as a sidewall 115. As used herein, if the can body 100 is at an advanced processing stage, a "sidewall" 115 may include the flange 110 and neck 105 components. In other embodiments, earlier in the can processing stage, the sidewall 115 may be short resulting in a shallow cup or the sidewall may be drawn and ironed without a neck 105 or flange 110. The can body 100 may also include a bottom 120 having a dome 125 and a rim 130, if the can body is in an advanced stage of processing. In other embodiments, earlier in the can processing stage, the can bottom 120 may be substantially flat. Each of the foregoing features of the can body may or may not be present for the plasma treatment depending on the stage of processing.

[0025] The can ends may also go through a series of processing operations including one or more of a press to form can end blanks, a curl of the can ends' edge, application of a compound sealant in the curl of the can ends, scoring of the can ends, and application of tabs to the can ends, among other possibilities. The term "can end" may refer to the various forms of the can end during any of the various processing operations. An example can end 200 that has been through the foregoing manufacturing processes is shown in FIG. 2. The can end 200 may have a tab 205 coupled to a main panel 210 via a rivet 215, for example. The tab 205 may define a tab tongue 206 and a horseshoe lance 207. The main panel 210 may define an outer downward facing curl 211. A main score 220 may be provided on the surface of the main panel 210 and define a deboss panel 225. An anti-fracture score 230 and a D-bead 235 may each be defined on the deboss panel 225. A vent coin 240 may be provided along the anti-fracture score 230. A nose coin 245 may also be provided on the main panel 210. Each of the foregoing features of the can end may or may not be present for the plasma treatment depending on the stage of processing.

[0026] Each of the features of the can body and the can end may be selectively treated with plasma to create different surface properties or coatings. Alternatively, the various features of the can body or can end may be collectively treated with plasma at the same time to achieve the same coating or surface properties. The methods disclosed herein may involve a precursor plasma plume or a precursor-free plasma plume directed at a surface of the can body or can end during or in between any of the foregoing operations to form a can body or a can end or other can component during or after operations to couple the can end to the can body. In addition, the surface of the can component in the path of the plasma plume may be an inner surface or an outer surface of the can component. In addition, the precursor plasma plume and the precursor-free plasma plume may be applied to the can component in series. The precursor plasma plume may be applied before or after the precursor-free plasma plume depending on the desired effect on the can component.

[0027] Alternatively the can body may have a longer neck and a bottle finish, such as ROPP threads or an end adapted to receive a Maxi P closure or a crown. The ROPP, Maxi P or crown closures are also contemplated under the definition of a can component.

[0028] Another alternative is that the can body may be seamed to a metal dome that may have a twist on/off cap. The metal dome may be made via a blank and draw and subjected to a series of processing operations, including forming the shape and rolling the edge. The cap may have a liner made of a flexible film or may be a formed with a liner that adheres to the cap. For example, in operation, a preformed cap may enter into a liner machine, the cap may be preheated, a dollop of preformed liner material may be added to the cap, then a forming tool compresses the dollop to shape the liner into the desired geometry necessary to effectively seal the can dome.

[0029] In some embodiments, the methods described herein may be used to treat aluminum sheet feedstock instead of a can component described above. The feedstock may be cut and formed into a cup to form the start of a can body.

[0030] The can component manufacturing process is unique due to high speed (creating up to 2000 to 3000 can components per minute or more), low tolerances, exacting manufacturing processes, and food safety requirements. The higher speeds and the extreme processing conditions seen downstream may require adaptions to introduce plasma treatment into the processing methods. Plasma treatment may be beneficially introduced during known bottlenecks or slower processing segments, among other possibilities.

[0031] Manufacturing of can components may be done using contact tooling that may have excessive wear due to a manufacturing process runs nearly continuously at a high rate of components per minute. In some embodiments, the methods described herein may be used to treat contact tooling. This may lower the coefficient of friction thereby decreasing wear of this expensive and specialized tooling. This contact tooling may be used to manufacture the can components discussed above.

[0032] The present embodiments advantageously provide methods for applying a protective layer to a can component and/or for modifying surface properties of a can component. Referring now to FIG. 3, one embodiment of a precursor plasma gun 300 is shown defining a housing 305 that has an insulator 306. An electrode 310 may be centrally disposed in the housing 305 between a metering plate 315 and a nozzle head 320. The electrode 310 may be coupled to power supply 325. In one embodiment, the electrode may energize the plasma gun with an electric potential of at least about 5,000 volts. A gas chamber 330 may be defined by the housing 305 between the metering plate 315 and the back end 335 of the plasma gun 300 located opposite to the nozzle head 320. A gas inlet 340 may defined in housing 305 in the area defining the gas chamber 330. In operation, a gas may advance through a supply line to the gas inlet 340 and into the gas chamber 330 and then pass through a plurality of holes 316 defined in the metering plate 315 and to the electrode 310. An electric potential from the electrode 310 may then transition the gas into plasma 345 in a discharge zone 311 of the housing 305, the plasma 345 may exit the plasma gun 300 as a plasma plume 346 via the nozzle head 320 and be directed at a surface of a can component 350. In this embodiment, a precursor inlet 355 is defined in the nozzle head 320 near the end of the electrode 310. In operation, a supply line 356 feeds a precursor gas or precursor aerosolized solution through the precursor inlet 355 into the flowing plasma 345 in the nozzle head 320 and the precursor exits the nozzle head as part of the plasma plume 346. In one embodiment, the precursor inlet may not be present or the precursor supply may not be flowing such that this is a precursor-free plasma gun. If the precursor supply is flowing, then this is a precursor plasma gun. The precursor-free and precursor plasma guns are discussed with respect to the methods 400 and 500 below.

[0033] FIG. 4 is a flow chart of a method 400 that includes, at block 405, directing a precursor plasma plume at a surface of a can component via at least one precursor plasma gun. In this embodiment, the precursor plasma plume comprises an ionized gas and an ionized precursor. Then, at block 410, the precursor plasma plume treats at least a portion of the surface of the can component thereby forming a first layer on the portion of the surface of the can component treated with the precursor plasma plume. In operation, the components of the plasma stream may bond and polymerize, for example, forming a first layer on the surface of the can component. In various embodiments, the first layer may include a siloxane network, such as glass, a small molecule or metal layer, or polymer network. In one embodiment, the first layer may be at least one atom thick and may range up to about 1000 nm.

[0034] In one embodiment, the can component may include aluminum or steel, among other possibilities. In an alternative embodiment, in which contact tooling is the target of the plasma treatment, tooling may include carbon nitride, tungsten carbide or other hardened materials. The foregoing materials may have the benefit of being generally non-reactive.

[0035] In a further embodiment, methods 400 may beneficially reduce VOC emissions and be carried out under atmospheric pressure. Alternatively, methods 400 and 500 may be carried out under vented conditions or under vacuum.

[0036] In an additional embodiment, treating at least the portion of the surface of the can component with the precursor plasma plume may include flowing a precursor plasma from the precursor plasma plume along a contour of the surface of the can component. For example, in a further embodiment, the can component may include a sidewall coupled to a bottom surface that defines a dome and a rim. In this embodiment, the precursor plasma plume may be directed at the dome and the precursor plasma may flow from the precursor plasma plume along the dome and treat the dome such that the first layer is formed on the dome. The plasma treatment in this embodiment may be applied by a single precursor plasma gun directed at the center of the dome or by a plurality of precursor plasma guns directed at evenly spaced targets about the dome. In a further embodiment, the single precursor plasma gun may be used to treat a can component for about 25 to about 1000 milliseconds, and in a further preferred embodiment the can component may be treated with plasma for about 400 milliseconds. For larger can components such as aluminum sheet on coils, the treatment would be continuous and the component moved relative to the plasma gun. The treatment times noted herein may be adjusted based upon a variety of factors, such as the flow rate of the gas, the number of plasma guns, and/or the size or configuration of the desired treatment area. For example, in one embodiment, treatment of a sheet of aluminum feedstock with plasma may be continuous as the sheet moves relative to the plasma plume.

[0037] In an alternative embodiment, the precursor plasma plume may instead be directed at the rim, and the precursor plasma may flow from the precursor plasma plume along the rim, the dome and a portion of the sidewall and treat these features such that the first layer is formed on the rim, the dome and the portion of the sidewall. In this embodiment, a plurality of precursor plasma guns may be utilized and be evenly spaced about the rim. In a further embodiment, four precursor plasma guns may be used. In a still further embodiment, each can component may be treated with plasma by the four precursor plasma guns for about 10 milliseconds to about 4000 milliseconds. For example, advancing 300 can components per minute, may permit each to be treated for 200 milliseconds. In an additional embodiment, a single precursor plasma gun may be utilized and directed at the rim. In this embodiment, each can bottom may be treated with plasma for about 500 milliseconds to about 1000 milliseconds, or more preferably about 750 milliseconds, which may allow about 80 cans per minute to be processed. In further embodiments, a plurality of plasma guns may be arranged in series and the can component may be advanced past each of the plasma plumes. In embodiments in which a precursor-free plasma plume is used instead, the plasma may flow and treat in a similar manner but instead of forming a protective layer, the surface properties of the can component may be changed instead, as discussed in more detail below with respect to method 500.

[0038] In another embodiment, at least the portion of the surface of the at least one of the can component, the feedstock and the tooling may be treated with the precursor plasma plume. For example, at least a portion of the surface of the tooling may be treated, and a precursor plasma may flow from the precursor plasma plume along at least one of a contour, a crevice, a score, a joint and an indentation of the surface of the tooling. In a further embodiment, one or more of a contour, a crevice, a score, a joint and an indentation on the surface of the tooling may be traced with the precursor plasma plume or with the precursor-free plasma plume.

[0039] In still another embodiment, a plurality of precursor plasma plumes may be directed at the feedstock. The plurality of precursor plasma plumes may be arranged adjacently or with overlapping footprints. At least the portion of the surface of the feedstock may be treated with the plurality of precursor plasma plumes and precursor plasma may flow from the plurality of precursor plasma plumes along the surface of the feedstock such that the first layer is formed on the feedstock.

[0040] In addition to forming a first layer on the portion of the surface of the can component treated with the precursor plasma plume, the precursor plasma plume may also beneficially alter the surface properties of the can component. For example, in one embodiment, a contaminant or secondary material present on the portion of the surface of the can component treated with the precursor-free plasma plume may be removed. In another embodiment, the surface energy of the portion of the surface of the can component treated with the precursor plasma plume may be raised or lowered. In a still further embodiment, functional groups may be added to the portion of the surface of the can component treated with the precursor plasma plume. The benefits and effects of changing the surface energy or surface properties of the can component are discussed in more detail with respect to method 500.

[0041] In another embodiment, at least one precursor plasma gun may have a nozzle outlet and the nozzle outlet may be arranged at least about 0.1 mm to about 1 cm, and preferably about 1 mm to about 5 mm, away from the surface of the can component during coating. In another embodiment, the nozzle of each of the plasma guns may be angled from about 0 to about 90 degrees, preferably about 35 degrees to about 90 degrees relative to the target surface of the can component.

[0042] In a further embodiment, the precursor plasma and precursor-free plasma may preferably flow at about 20 psi to about 100 psi, or more preferably at about 40 psi.

[0043] In one embodiment, the at least one precursor plasma plume may be a single precursor plasma plume that has a footprint sized to match a footprint of the can component. The size of the footprint of the plasma plume may be controlled by altering the distance of the plasma gun nozzle from the surface of the can component. For example, the footprint of the plasma plume may increase as the distance of the plasma plume from the target surface of the can component increases. Increasing the distance of the plasma plume from the target surface of the can component may also result in a plasma plume with a lower energy density. In another embodiment, method 400 may include rotating the can component 360 degrees in a path of a single precursor plasma plume. In this embodiment, the plasma plume may be arranged closer to the surface of the can component to maintain a higher energy density plasma plume. This embodiment may be useful in applying a plasma treatment to the rim of the can bottom or in applying a plasma treatment to the neck and/or flange of the sidewall, for example. This embodiment may also be useful with a precursor-free plasma plume applied to the inner surface of the curl of a can end, for example, to facilitate the bond between the surface of the can curl and a sealing compound. In an alternative embodiment, the plasma plume may also be applied to a continuous roll of sheet aluminum, to coat or clean the feedstock as it enters manufacturing.

[0044] In various embodiments, the precursor plasma plume and/or the precursor-free plasma plume may be used to trace (i) exposed aluminum on a can component, such as a score, (ii) a can component feature with weakened coating, such as mechanical or laser marking, or (iii) other highly-worked can component features such as threading or rivets on the surface of a can component. In operation, the plasma gun may be physically moved to trace the targeted can component. Alternatively, a support holding the can component may move the can component in the path of the plasma plume to trace the score, for example. In one embodiment, the precursor-free plasma may be used to clean the score and then the precursor plasma plume may be used to apply a protective sealing layer to the score.

[0045] In another embodiment, the at least one precursor plasma plume may include four precursor plasma plumes, including a central precursor plasma plume and three peripheral precursor plasma plumes. The central precursor plasma plume may be aligned with a central axis of the can bottom and the three peripheral precursor plasma plumes may be aligned with the rim of the can bottom and may be spaced equidistantly apart from each other. The same arrangement of plasma plumes may be utilized for a precursor-free plasma plume.

[0046] Each of the foregoing arrangements and embodiments may be utilized with respect to a precursor-free plasma plume unless the context dictates otherwise.

[0047] FIG. 5 is a flow chart of a method 500 that is provided that includes the step 305 of directing a precursor-free plasma plume at a surface of a can component via at least one precursor-free plasma gun. In this embodiment, the precursor-free plasma plume comprises an ionized gas. This embodiment also provides that the surface of the can component is contoured or has a score. Then at step 510, method 500 includes treating at least a portion of the surface of the can component with the precursor-free plasma plume.

[0048] In one embodiment, method 500 may be implemented in series with method 400 either before or after method 400 has been used to treat the surface of a can component. In this embodiment, method 500 and the various embodiments that follow may be used to treat any surface of the can component and are not limited to a surface of the can component that is contoured or has a score.

[0049] In one embodiment, method 500 may also include the step of removing at least one contaminant, oxide layer, previously applied coating or other secondary material present on the portion of the surface of the can component treated with the precursor-free plasma plume. In operation, the precursor-free plasma plume may remove contaminants by breaking apart organic bonds and/or reacting with contaminants resulting in vapors or gases that leave the surface of the can component. Alternatively, the force of the plasma flow against the surface of the can component may evacuate contaminants from the target surface such as dust or weakly held molecules.

[0050] In another embodiment, method 500 may include raising the surface energy of a portion of the surface of the can component coated with the precursor-free plasma plume. Changing the surface energy of the can components to be higher energy than that of a pre-existing coating or treatment and may improve the can component's ability to be wet. For example, if ink is desired on a surface, increasing the surface energy would increase the wetability of the ink to the can component surface. If an even coat of polymer is desired, then increasing the surface energy above that of the target polymer may help the polymer laydown in the desired area of the can component. In another example, a subsequent chemical treatment may more evenly cover the surface of a highly energized surface.

[0051] In another embodiment, method 500 may include lowering the surface energy of a portion of the surface of the can component. Lowering the surface energy of the can component to a point lower than that of a pre-existing coating, treatment, or lubricant on the surface of the can component will improve the can component's ability to dewet or aid in sheeting of a coating, treatment, or lubricant. For example, rinsing stages of the can manufacturing process often contain contaminants that may concentrate through drying and create potential defects. Improved dewetting may beneficially allow sheeting of rinse stages to prevent any liquid from remaining on the surface of the can component and may lower drying time and energy required. In another example, dewetting may create desired features by causing preferential thinning of inks and varnishes in treated areas, so that the ink or varnish may have a textured feel on the can component.

[0052] In another embodiment, method 500 may include adding functional groups to the surface of a portion of a can component. Adding these functional groups may allow for a strong, covalent bond between the can component and another material or other can component. In a further embodiment, the functional group may remain active, as a free radical, and may initiate a reaction with a precursor, coating, or other can component, for example, bonding a liner to a cap.

[0053] The above detailed description describes various features and functions of the disclosed apparatus and methods with reference to the accompanying figures. While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims. The various aspects of the methods and the various embodiments may be combined unless context dictates otherwise.

Claims

1. A method, comprising: directing a precursor plasma plume at a surface of a can component via at least one precursor plasma gun, wherein the precursor plasma plume comprises an ionized gas and an ionized precursor; and treating at least a portion of the surface of the can component with the precursor plasma plume and thereby forming a first layer on the portion of the surface of the can component treated with the precursor plasma plume.

2. The method of claim 1, further comprising: directing a precursor-free plasma plume at the surface of the can component via at least one precursor-free plasma gun, wherein the precursor-free plasma plume comprises an ionized gas; and treating at least a portion of the surface of the can component with the precursor-free plasma plume.

3. The method of claim 2, further comprising: removing at least one contaminant or secondary material present on the portion of the surface of the can component treated with the precursor-free plasma plume.

4. The method of claim 2, further comprising: raising or lowering the surface energy of the portion of the surface of the can component treated with either the precursor-free plasma plume or the precursor plasma plume.

5. The method of claim 2, further comprising: adding functional groups to the portion of the surface of the can component treated with either the precursor-free plasma plume or the precursor plasma plume.

6. The method of claim 1, wherein the first layer is at least one atom thick.

7. The method of claim 1, further comprising: energizing the at least one precursor plasma gun with an electric potential of at least about 5,000 volts.

8. The method of claim 1, wherein at least one precursor plasma gun has a nozzle outlet and the nozzle outlet is arranged at least about 0.1 mm to about 1 cm away from the surface of the can component during treatment.

9. The method of claim 1, wherein treating at least the portion of the surface of the can component with the precursor plasma plume comprises flowing a precursor plasma from the precursor plasma plume along a contour of the surface of the can component.

10. The method of claim 1, wherein the can component is a sidewall coupled to a bottom surface that defines a dome and a rim, wherein directing the precursor plasma plume at the surface of the can component via the at least one precursor plasma gun comprises directing the precursor plasma plume at the dome, and wherein treating at least the portion of the surface of the can component with the precursor plasma plume comprises flowing a precursor plasma from the precursor plasma plume along the dome such that the first layer is formed on the dome.

11. The method of claim 1, wherein the can component is a sidewall coupled to a bottom surface that defines a dome and a rim, wherein directing the precursor plasma plume at the surface of the can component via the at least one precursor plasma gun comprises directing the precursor plasma plume at the rim, and wherein treating at least the portion of the surface of the can component with the precursor plasma plume comprises flowing a precursor plasma from the precursor plasma plume along the rim, the dome and a portion of the sidewall such that the first layer is formed on the rim, the dome and the portion of the sidewall.

12. The method of claim 1, wherein the at least one precursor plasma plume is a single precursor plasma plume, wherein a footprint of the single precursor plasma plume is sized to match a footprint of the can component.

13. The method of claim 1, further comprising: rotating the can component 360 degrees in a path of a single precursor plasma plume.

14. The method of claim 1, further comprising: tracing a score on the surface of a can component with the precursor plasma plume.

15. The method of claim 2, further comprising: tracing a score on the surface of a can component with the precursor-free plasma plume.

16. The method of claim 1, wherein the at least one precursor plasma plume comprises a plurality of precursor plasma plumes spaced apart from each other and each directed at a target portion of the surface of the can component.

17. The method of claim 1, wherein the can component comprises aluminum.

18. A can component treated according to the method of claim 1.

19. A method, comprising: directing a precursor-free plasma plume at a surface of a can component via at least one precursor-free plasma gun, wherein the precursor-free plasma plume comprises an ionized gas, wherein the surface of the can component is contoured or has a score; and treating at least a portion of the surface of the can component with the precursor-free plasma plume.

20. The method of claim 19, further comprising: after treating the portion of the surface of the can component with the precursor-free plasma plume, directing a precursor plasma plume at the surface of the can component via at least one precursor plasma gun, wherein the precursor plasma plume comprises an ionized gas and an ionized precursor; and treating the portion of the surface of the can component with the precursor plasma plume and thereby forming a first layer on the portion of the surface of the can component treated with the precursor plasma plume.

21. The method of claim 19, further comprising: removing at least one contaminant or secondary material present on the portion of the surface of the can component treated with the precursor-free plasma plume.

22. The method of claim 19, further comprising: raising or lowering the surface energy of the portion of the surface of the can component treated with the precursor-free plasma plume.

23. The method of claim 19, further comprising: adding functional groups to the portion of the surface of the can component treated with the precursor-free plasma plume.

24. A can component treated according to the method of claim 19.

25.-45. (canceled)