AU716563B2 - Surface treatment - Google Patents

Description

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AUSTRALIA

Patents Act 1990 NAME OF APPLICANT:-.

ACTUAL

INVENTOR:-

ADDRESS FOR SERVICE:- INVENTION

TITLE:-

CONVENTION

PRIORITY:

AUCKLAND ANODISERS

LIMITED

John Arnold MacCulloch PIZZEYS PATENT TRADE

MARK

ATTORNEYS

GPO Box 1374 BRISBANE QLD 4001 "SRFC

TREATMENT

NZ Patent Application No. 272662 filed 27 July 1995 a a a a.

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"SURFACE TREATMENT' BACKGROUND TO THE INVENTION 1. FIELD OF THE INVENTION This invention relates to surface treatment coating and texturing of materials and more particularly to the decorative surface treatment and modification of materials, for example metals.

Whilst in the invention reference is made to etching and texturing of aluminium or aluminium alloy materials as part of an anodising process, the invention is not limited to such techniques and technology.

2. DESCRIPTION OF THE PRIOR ART In the past various methods and techniques have been utilised to provide decorative surface treatment, for example S" 15 treatment of metal panelling and the like, as is often used in building interiors and sometimes on building exteriors and the like.

Various methods have been adopted to achieve surface treatment including various mechanical actions such as 20 scratching and abrasion, dimpling and similar. Further, techniques using etching processes have also been used, however such use has been in the main limited to less durable metal surfaces which need additional surface protection. This may be by way of surface coatings and or including colouring and the like which may tend to break down. Such break down may occur -3foregoing factors limit use of such surfaces to those which are ordinarily additionally protected. This may typically be by use only for interior applications.

OBJECT OF THE INVENTION It is an object of this invention to come some way in overcoming the above-mentioned problems or alternatively, at least provide the public with a useable choice.

SUMMARY OF THE INVENTION In a first aspect the invention is a surface treatment process for an anodisable metallic substrate, said process comprising or including the steps taking a said substrate with a surface characteristic of a first kind, (ii) applying masking material to some zone or zones of such surface of a first kind, .(iii) subjecting both the masked and unmasked surfaces resulting from step (ii) to an etching process to provide an etching effect on the unmasked surface and to partially erode the masking material, (iv) subjecting the resultant surfaces of step (iii) to an anodisation process which will provide a surface characteristic different to that of said surface of a first kind (ie, a surface of a second kind), and optionally removing any remaining masking material after step (iv), the process providing a composite surface for said substrate having, at 0 different zones of its surface, a surface or surfaces of the first kind and a surface or surfaces of the second kind, such first and second kind surfaces being separated by a transition of a different kind of surface or surfaces resulting from either the anodisation of step (iv) being applied to lesser etched first kind surface(s) or being effective through slightly masked surface or surfaces.

Preferably step (iii) includes or is part of an electrical or electrochemical process.

Preferably said surface treatment process is performed substantially as hereinafter described with reference to the accompanying drawings.

In another aspect the invention consists in an article having a surface S resulting from the performance of a process as previously set forth.

4 be incorporated without departing from the scope or spirit of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS One form of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a substantially perspective view of a portion of material providing an surface in accordance with the method and apparatus of the invention.

Figure 2 is a substantially cross sectional side elevation through a panel coated with mask material according to the invention and surface alteration.

Figure 3 is a substantially diagrammatic flow path of a typical surface alteration process using an etch process according to the method of the invention.

Figure 4 is a cross sectional side elevation of an etched surface substantially according to the invention shown in p.

exaggerated relief.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the preferred form of the invention, the method and toto 20 apparatus is utilised for the purposes of providing decorative panelling for the exterior and interior of buildings, preferably formed from aluminium alloy sheet or extrusion material suitably configured with patterning. Whilst the invention is described with reference to this form, the invention is not limited to such a usage and alternative usages are envisaged.

The invention employs the use of a predetermined masking material which is preferably a material which is able to adhere to a mill finish or otherwise etchable surface of aluminium alloy sheet and which may adhere thereto at least sufficiently for the etching processes according to the invention. In the preferred form of the invention, mask materials include the following: 1. Paints and other surface coatings such as asphaltum, soft or hard ground as used in the fine arts industry and the like.

2. Oils, oil stick, shellac, glazes and pastels.

3. Sheet material including self adhesive sheet materials, laminates and the like.

In further embodiments, it is envisaged that the mask material may be incorporated with a conductive electrolyte material therein, so as to create a predetermined electrical S conductivity throughout the mask material when exposed to etch processes.

Referring now to the drawings, in the preferred form of 20 the invention and with reference to particularly Figure 2, the panel as indicated by arrow 1 is preferably provided with an l etchable surface 2 which is in the preferred form of the invention preferably a mill finish sheet or extrusion or aluminium surface which may be pre-treated, for example by wire brushing, swirling, or otherwise deforming rollers, pressers or particle blasting, so as to provide an "interesting" surface.

Thereafter, a "mask" 3 is applied to the surface in a predetermined or random configuration, so as to achieve the required decoration for the surface 2.

In the preferred form of the invention, preferably the etchable surface 2 is preferably coated in some areas and exposed in others, so that the mask material 3 creates a random pattern, in the example shown.

In other forms of the invention, it is envisaged that screen printing or other processes may be utilised to provide a more reproducible form of patterning, however this is in no way essential to the invention.

In the preferred form of the invention, preferably a mask in the form of a sheet screen, tape, painted hand art and the like is applied to the etchable surface 2 in such a manner that the mask 3 adheres to the surface 2 once stabilised or solidified in various thicknesses. Should it be desired, or should characteristics of the mask 3 be so predetermined, two or more layers of the same or differing mask materials 3a and 3b may be applied one over the other, so as to achieve predetermined results.

Further, variation in the available setting and/or curing 20 time prior to etching can be utilised to achieve the desired results.

~The surface to in some forms of the invention may *9 additionally be deformed prior to application of the mask material to the surface, or subsequently.

It will be appreciated that in such circumstances, traditional "exposure" of the etchable surface 2 is thus provided, to achieve predetermined effects in use.

Now turning to Figure 3, it will be appreciated that sketch A shows diagrammatically the application of the mask 3 to the etchable surface 2. This application can be by way of brush, spray, screen printing or other application techniques.

Thereafter, as determined, when wet, dry, stabilised or cured to a predetermined degree the sheet 1 is immersed into an etch bath 10 for etching. In the preferred form, electro etching conditions are provided which may be "pulsed" or "ramp" however this is not essential to the invention and alternative etching processes can be used, such as chemical or mechanical etching processes.

It is the characteristic of this invention that the mask 3 is formed in a form which over time is attackable by the etch 11 so that a variation in the degree of etching, or time of etching is achieved between surfaces which were masked and those which were unmasked. This different etch time and temperature and concentration and type of etch creates a S. surface configuration and a variation in the affect.

It will be appreciated that by varying the thickness or permeability, characteristics and layer combination of the mask S" 20 material, varying rates of exposure of the masked etchable surface can be achieved.

l In the preferred form of the invention and utilising mask materials such as asphaltum, it has been found that removal of the mask material over time is achieved substantially chemically and/or mechanically, however, in alternative forms of the invention it is envisaged that the mask material 3 will not be removed chemically and/or mechanically, but will provide a variation in the extent or nature of etching carried out beneath the mask, for example where a partial mask may be provided by the mask material 3, thus providing different surface affects on completion of the.etching process, to surfaces which are exposed, originally unmasked.

Whilst the invention is described with reference to a single of masking and etching, it is envisaged that in alternative forms, the mask and etch process can be repeated several times to provide the required result and a variation in the etched surface.

It will be appreciated that by varying the layers and compositions of the mask 3, a variety in the etching affects can be achieved, which creates a-gradation or variation in the physical contours in the treated surface, such as by microscopic pitting and removal of the etchable surface layer.

It is envisaged subsequently that after the etching processes B and C of Figure 3, the panel may thereafter be S anodised or powdercoated or painted according to known anodising, powder coating or painted techniques, to thus S" provide a durable surface over the variably etched surface.

20 If the surface is not provided in aluminium or aluminium alloy a suitable surface treatment may be provided for the surface concerned. Such treatments may be in the form of galvanising, electroplating, laminating, lacquering and the like.

As an alternative development in the process, it is envisaged that after the etch step C, the panel 1 may be removed from the etch process and be re-treated with mask material for repeating of the process B and C, to thus provide 9 further enhanced variable surface treatments. Repetition of the etch step may be provided in certain instances.

It is envisaged that ultimately that the etched surface 2 will have a relief surface thereon much in the manner as graphically shown in an exaggerated form of Figure 4 where greatest removal of material is found in the region of unmasked surfaces and least in the most properly masked surfaces.

However the process may also include a mechanical and physical building up of the surface level and/or contours such as by surface coatings and the like.

It will thus be appreciated that by "partial masking" of the surface during etch processes and by ranging the mask in a manner which will provide partial masking either by mechanical or chemical removal means or by delective transmissibility of the etch process to the masked surface, a variety of surface configurations can be achieved, which provides a detectable eq C effect.

oWhilst the invention has been described with reference to the use of the partial masking in aluminium or aluminium alloy materials and as a step in an anodising process, the invention is not limited to such a process and may be incorporated in other processes where partial masking is able to be utilised.

Further, whilst the invention has been described in the preferred embodiment with reference to an etch process, in alternative forms of the invention the surface alteration may be provided by a surface coating or surface build-up, for example in the form of paints, electroplates resins and the like. In one assembly, it is envisaged that a variety of gloss or mirror affects may be provided with multiple gloss and physical contour levels to achieve a desired result. Further, a combination of application or surface build-up or etch processes may be provided to achieve surface alteration.

Thus by this invention there is provided a method and apparatus for decorative coating of surfaces by etching.

o

Claims (4)

1. A surface treatment process for an anodisable metallic substrate, said process comprising or including the steps taking a said substrate with a surface characteristic of a first kind, (ii) applying masking material to some zone or zones of such surface of a first kind, (iii) subjecting both the masked and unmasked surfaces resulting from step (ii) to an etching process to provide an etching effect on the unmasked surface and to partially erode the masking material, (iv) subjecting the resultant surfaces of step (iii) to an anodisation process which will provide a surface characteristic different to that of said surface of a first kind (ie, a surface of a second kind), and optionally removing any remaining masking material after step (iv), the process providing a composite surface for said substrate having, at different zones of its surface, a surface or surfaces of the first kind and a surface or surfaces of the second kind, such first and second kind surfaces being separated by a transition of a different kind of surface or surfaces resulting from either the anodisation of step (iv) being applied to lesser etched first kind surface(s) or being S effective through slightly masked surface or surfaces.

2. A process of claim 1 where step (iii) includes or is part of an electrical or S• electrochemical process. roes

3. A surface treatment process as claimed in claim 1 or claim 2 when performed substantious hereinbefore described with reference to any of the accompanying drawings.

4. An article having a surface of an anodisable metallic substrate resulting from the performance of a process as claimed in any one of the preceding claims. DATED THIS 2 9 TH DAY OF NOVEMBER 1999 AUCKLAND ANODISERS LIMITED BY PIZZEYS PATENT TRADE MARK ATTORNEYS