Patent Application
20180230617
This applicant claims the foreign priority benefit of British Application No. 1702213.8 filed Feb. 10, 2017 for “Aluminium Panels” by C. Edge, which is incorporated by herein by reference.
The present disclosure relates to panels made from anodized aluminum and from anodized aluminum alloys and a method for producing such panels, and in particular to panels including a recessed design.
Aluminum signs or nameplates are typically made from anodized aluminum panels.
Anodizing is an electrochemical process which provides the surface of a metal, such as aluminum, with an oxide coating. This anodized coating is porous and can absorb dyes to provide the panel with a colored layer. The anodized coating must then be sealed using a sealing process which seals the pores in the coating. Anodizing increases corrosion and wear resistance of the panel and the anodized coating is non-conductive of electricity.
Sulphuric acid is commonly used in the preparation of anodized aluminum, producing coatings of moderate thickness, for example 1.8 μm to 25 μm thick. These coatings are known as type II coatings.
Different sealing processes are commonly used, including hot water sealing where the panel is immersed in boiling de-ionized water for a certain amount of time, and cold sealing methods, where for example the panel may be immersed in a solution of a nickel salt, such as nickel fluoride.
Pre-anodized aluminum sheets are often used in making signs. Designs can be engraved or etched into the anodized panels and paint can be added to the etched or engraved areas. However, since the paint is applied to the metal surface it is less durable than dyes encapsulated within the anodic layer and also vulnerable to both wear and damage and degradation from solvents, pollutants or the environment.
Anoprinting is an alternative known method of printing onto aluminum panels to make signage. This process involves printing onto a freshly anodized, unsealed, porous surface, allowing the dyes to soak into the surface. After the color has been applied the anodized coating is sealed to trap the dye inside the anodized surface layer. In this process there is no etching and/or engraving so the surface of the signs is smooth and when a smooth surface is contaminated with dirt or soot it can be difficult to read. With signage of this type there is also no option to make the surface of the signs tactile and it can be difficult to read such signage from certain angles or in certain light conditions since the reflection from the surface is uniformly smooth. In addition, if the printed image becomes bleached for example through exposure to heat or light the image will be reduced in intensity or lost entirely. This type of signage is also unsuitable for use on a floor as the smooth surface is likely to provide a slip hazard, particularly when wet.
It would therefore be desirable to provide an improved aluminum panel.
According to an aspect of the present disclosure, there is provided an aluminum panel or an aluminum alloy panel comprising an upper surface and a lower surface, the upper surface comprising at least one recessed area, the panel having a reduced thickness in the at least one recessed area, wherein both the upper surface of the panel and the at least one recessed area are provided with an aluminum oxide coating, and wherein the aluminum oxide coating of the at least one recessed area includes at least one colored dye.
The depth of the recessed area should be sufficient to be discernible by sight or touch, preferably at least 0.1 mm relative to the upper surface of the panel.
Preferably the aluminum oxide coating is obtained by electrolytic anodizing treatment. More preferably the electrolytic anodizing treatment is a sulphuric acid electrolytic anodizing treatment.
The aluminum oxide coating of the at least one recessed area may be unsealed. Alternatively, the aluminum oxide coating of the at least one recessed area may be sealed. Anodized aluminum oxide coatings are preferably sealed using a standard sealing process selected from the group comprising: hot water sealing, steam sealing, nickel salt cold sealing, chromate sealing and dichromate sealing processes.
The aluminum oxide coating of the recessed area may include more than one dye. The aluminum oxide coating of the upper surface of the panel may include at least one dye. The aluminum oxide coating of both the upper surface of the panel and the aluminum oxide coating of the recessed area may each include at least one dye. The dye included in the aluminum oxide coating of the upper surface of the panel may be a different color to the dye included in the aluminum oxide coating of the recessed area.
The aluminum panel may be selected form the group comprising: labels, nameplates, signs, badges, and flooring.
According to a further aspect of the present disclosure there is provided a method for producing an aluminum panel comprising the steps of:
taking an aluminum panel, the panel comprising an upper surface and a lower surface, the upper surface having an anodized coating, and removing part of the aluminum oxide coating and a proportion of the underlying aluminum to create a recessed area on the panel; and
connecting the panel to a power supply and anodizing the exposed aluminum parts of the recessed area of the panel such that the recessed area is provided with an aluminum oxide coating.
The method may comprise a final step of:
(c) sealing the anodized coating of the recessed area.
Preferably the aluminum oxide coating on the panel in step (a) is obtained by electrolytic anodizing treatment. More preferably, the electrolytic anodizing treatment is a sulphuric acid electrolytic anodizing treatment.
The method may include an additional step of applying at least one colored dye to the panel after step (b) and before step (c).
Preferably, the recessed area created in step (a) has a depth of at least 0.1 mm relative to the upper surface of the panel.
Step (a) may be a two-step process, and comprises the steps of first removing the anodized coating, and the subsequently removing the underlying aluminum. Each step of the two-step process may use a different removal process.
In step (a) the anodized coating may be removed by a process selected from the group comprising: chemical etching, engraving, laser engraving and sand blasting.
In step (a) the underlying aluminum may be removed by a process selected from the group comprising: chemical etching, engraving, laser engraving and sand blasting.
Preferably, in step (c) the anodized coating is sealed using a standard sealing process selected from the group comprising: hot water sealing, steam sealing, nickel salt cold sealing, chromate sealing and dichromate sealing processes. Where the sealing process is a hot water sealing process and the anodized coating is sealed by immersion in hot water, preferably water at a temperature of between 96 and 100° C., for a period of at least 20 minutes.
The aluminum panel used in the method may be selected form the group comprising: labels, nameplates, signs, badges, and flooring.
The term aluminum panel includes panels made from aluminum or alloys of aluminum.
In the Drawings, which illustrate preferred embodiments of the present disclosure:
The anodized coating 2 is removed from the exposed area 4 by applying an etching solution.
The panel 1 is then further etched or engraved to increase the depth of the image area 4 to form a recessed area on the panel 1, as shown in
The panel 1 is then connected to a power supply and the exposed aluminum surface 5 is re-anodized using a standard anodizing method, to produce an anodized coating 6, as shown in
At this stage, the freshly anodized coating 6 is porous and may be dyed by immersing in a dye solution, resulting in a colored anodized coating 6′ as shown in
Lastly, as shown in
The application of dye is an optional step and the anodized coating may be sealed without dyeing to produce a transparent layer.
The following example exemplifies the method of the present disclosure:
A piece of anodized aluminum plate with an anodized coating of thickness 25 μm had a simple cut-vinyl etching stencil applied to the anodized surface.
The anodized coating from the area exposed by the stencil was then removed by etching in 5% NaOH solution at 20° C. for about 3 minutes until the aluminum metal surface became visible.
The panel was then rinsed in water.
Using a standard spray etching machine, the panel was then etched in 20% Ferric Chloride solution at 20° C. for 15 minutes to increase the depth of the area exposed by the stencil.
The panel was then rinsed in water.
The panel was then connected to a power supply and was anodized in a tank using lead cathodes in a solution of 10% H2SO4 at 20° C. using a current of 0.018 A at 15 v for 50 minutes to produce an anodized coating of thickness of approximately 25 μm.
The panel was then removed from the power supply and was rinsed in de-ionized water.
The panel was then immersed in a standard black anodizing dye solution for 20 minutes at 20° C. until the dye had fully colored the applied anodized parts from step (vi).
The panel was then rinsed in water.
The panel was then immersed for 30 minutes in a standard sealing tank containing water at 97.5° C.
The stencil was then peeled from the surface and adhesive residue removed using a proprietary general purpose washing solvent.
Masking, or similar techniques may be employed to enable more than one colored dye to the panel.
Panels produced using this method include recessed detail or graphics and are useful as labels, name plates, signs, badges, or flooring for example. The recessed detail may help to enable improved tactile discernment of the information or graphics. The recessed design can also produce different reflective properties between the upper surface of the panel and the recessed surface.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1702213.8 | Feb 2017 | GB | national |
