FIELD OF THE INVENTION The present invention relates in general to the removal of markings off a substrate, and in particular to a method for removing a marking off a substrate and also to a kit for facilitating the removal of a marking off a substrate.

BACKGROUND OF THE INVENTION

We come across numerous types of substrates such as road signs, notice boards, walls, etc in everyday modern life. The substrates may have applied on their surface some form of coating (e.g. paint or adhered sheet or sticker) to impart weathering protection, decoration, and/or to carry some form of instructive written information or design.

Regardless of the purpose of the substrate, there will generally be someone or entity that is responsible for the substrate and who may also have an interest in its maintenance. In many instances, such maintenance may involve ensuring that the appearance of the substrate is preserved as intended. Appearance preservation may involve something as simple as washing the substrate down with water as required.

However, it is not uncommon for the surface of substrates to be marked in a way that makes cleaning it difficult. For example, the substrate may be exposed to substances that stain or adhere very well to its surface. Such substances might include paint, ink, general pollution, dirt mud, oil/grease and excrement (e.g. bird poo).

A particular form of marking might also be in the form of graffiti. Graffiti is becoming an ever increasing problem in areas that can be accessed by the general public. Historically, the term "graffiti" did not have a negative connotation. However, the term has now become know to mean an unwanted, undesirable and unauthorised word, figure, mark, symbol or design (often referred to as a tag) that is applied to the surface of the substrate using some form of marking means such as paint (e.g. aerosol paint), marking pen (e.g. felt tipped marker), pencil, crayon, lipstick, and the like.

Graffiti is commonly applied to substrates that have a visible presence to the public such as road signs, advertising boards, shop fronts or walls, and the like.

It is common for markings, such as graffiti, to present on a substrate surface (either intentionally, unintentionally, authorised or unauthorised) that are required to be removed, but doing so can not be achieved with simple washing of water

In some cases, marks present on a painted substrate that are difficult to remove can be addressed by simply painting over the mark effected area using an appropriately coloured paint that matches the non-marked effected areas. However, painting over a mark effected area can sometimes be problematic. For example, it may be that the newly painted section presents as a noticeably different shade of colour (e.g. due to weathering of, or a non-perfect colour match to, the adjacent non painted area) thereby necessitating painting of both mark effected and non-mark effected areas. Furthermore, the marking may be applied over an image or indicia present on, for example, an advertising board or road sign, making repainting or reprinting the design and/or indicia impractical.

Faced with these problems, two methods for combating marks on substrates have been developed.

The first of these methods involves forming a permanent and durable coating over the surface that is to be protected from marks. Such coatings are generally clear such that the underlying substrate surface to be protected can be readily viewed through the coating. Markings can still easily occur on, or be applied to, such permanent protective coatings, but they are typically designed to resist adhesion of the markings and/or be capable of withstanding chemical cleaners that can remove markings from the coatings while leaving the coating substantially in tact.

Whilst effective to some extent, permanent protective coatings developed to date are generally quite expensive. Upon being subjected to cleaning chemicals, the coatings can also develop micro cracks on the surface leading to the ingress of the marking materials within the coating layer that can be difficult to remove and lead to what is known as a "ghosting" mark being left behind after the bulk of the marking has been removed. The use of cleaning products to clean off the marking can also present occupational health and safety issues for the cleaner.

The second method for providing protection against marking involves the use of a sacrificial protective coating. Unlike permanent protective coatings, a sacrificial protective coating is designed to form a non-durable coating on the surface of the substrate that is to be protected from marking. Upon the marking occurring on, or being applied to, the sacrificial protective coating, the marking is in effect removed by removing the sacrificial coating. High pressure cleaners are often employed to remove the marking/sacrificial protective coating. However, these have a tendency to also damage the underlying substrate thereby defeating the purpose for protecting it in the first place. The marking/sacrificial protective coating can also be removed with chemical cleaners, but this can lead to the same occupational health and safety issues outlined above.

An opportunity therefore remains to develop a more efficient and effective method for removing markings from a substrate, or at the very least to provide a useful alternative to state of the art methods for removing markings from a substrate.

SUMMARY OF THE INVENTION

The present invention therefore provides a method of removing marking from a substrate, the substrate having a peelable sacrificial surface layer on which the marking is located, the method comprising:

(a) applying an adhesive material onto the sacrificial surface layer and/or marking to form an adhesive layer such that at least some of the marking is interposed between the adhesive layer and the peelable sacrificial surface layer, said adhesive layer, peelable sacrificial surface layer covered by the adhesive layer, and the interposed marking forming an integral laminated structure; and

(b) peeling the laminated structure off the substrate so as to remove marking therefrom.

According to the present invention, a peelable sacrificial layer is used to protect the underlying substrate from marking. The peelable sacrificial layer can be made very thin to minimise cost and maximise its application efficiency. Whilst the peelable sacrificial layer has sound adhesion to the underlying substrate, this adhesion is lower compared with the overall adhesion between the components that form the laminated structure. Accordingly, the laminated structure comprising the marking can be readily peeled off the substrate so as to remove marking therefrom. The applied adhesive layer in effect functions as a support layer to facilitate peeling of the sacrificial surface layer off the substrate by forming the integral laminated structure. This function is particularly useful to facilitate peeling off sacrificial surface layers that are particularly thin and could not otherwise be readily peeled off the substrate without breaking.

The method in accordance with the invention is particularly advantageous in that removal of the marking from the substrate can be performed quickly and without the use of any harsh cleaning chemicals or high pressure cleaners. Furthermore, the method promotes little if no damage to the underlying substrate and does not adversely impact on other parts of the substrate that have not been marked.

Peeling the laminated structure off the substrate will not only remove marking therefrom, but also remove protective coating from the underlying substrate. However, a peelable sacrificial layer can be readily reapplied to again protect the substrate.

In one embodiment the marking is graffiti, and the invention provides for a method of removing graffiti from a substrate, the substrate having a peelable sacrificial surface layer on which graffiti is located, the method comprising:

(a) applying an adhesive material onto the sacrificial surface layer and/or graffiti to form an adhesive layer such that at least some of the graffiti is interposed between the adhesive layer and the peelable sacrificial surface layer, said adhesive layer, peelable sacrificial surface layer covered by the adhesive layer, and the interposed graffiti forming an integral laminated structure; and

(b) peeling the laminated structure off the substrate so as to remove graffiti therefrom.

The peelable sacrificial surface layer may be applied to a substrate that is to be protected from marking through use of a coating composition. Such a coating composition and an adhesive material for use in accordance with the invention can be conveniently provided together in a kit for facilitating the removal of marking from a substrate.

Accordingly, the present invention further provides a kit for facilitating the removal of marking from a substrate, said kit comprising:

(a) a coating composition that when applied to a substrate forms a peelable sacrificial surface layer on which marking occurs; and

(b) an adhesive material that when applied to a marking effected area of the peelable sacrificial surface layer forms an adhesive layer, which together with the peelable sacrificial surface that is covered by the adhesive layer and marking interposed there between forms an integral laminated structure. The present invention also provides a kit when used to facilitate the removal of marking from a substrate, said kit comprising:

(a) a coating composition that when applied to a substrate forms a peelable sacrificial surface layer on which marking occurs; and

(b) an adhesive material that when applied to a marking effected area of the peelable sacrificial surface layer forms an adhesive layer, which together with the peelable sacrificial surface that is covered by the adhesive layer and marking interposed there between forms an integral laminated structure.

In one embodiment the marking is graffiti, and the invention provides for a kit for facilitating the removal of graffiti from a substrate, said kit comprising:

(a) a coating composition that when applied to a substrate forms a peelable sacrificial surface layer onto which graffiti is applied; and

(b) an adhesive material that when applied to a graffiti effected area of the peelable sacrificial surface layer forms an adhesive layer, which together with the peelable sacrificial surface that is covered by the adhesive layer and graffiti interposed there between forms an integral laminated structure.

In the embodiment where the marking is graffiti, the invention also provides for a kit when used to facilitate the removal of graffiti from a substrate, said kit comprising:

(a) a coating composition that when applied to a substrate forms a peelable sacrificial surface layer onto which graffiti is applied; and

(b) an adhesive material that when applied to a graffiti effected area of the peelable sacrificial surface layer forms an adhesive layer, which together with the peelable sacrificial surface that is covered by the adhesive layer and graffiti interposed there between forms an integral laminated structure.

Further aspects of the invention are discussed in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will hereinafter be described with reference to the following non-limiting drawings in which: Figure 1 illustrates a side view of a peelable sacrificial surface layer applied to a substrate according to the present invention;

Figure 2 illustrates the arrangement shown in Figure 1 where marking has been applied a peelable sacrificial surface layer;

Figure 3 illustrates the arrangement shown in Figure 2, whereby an adhesive material has been applied onto the sacrificial surface layer and/or marking to form an adhesive layer thereon;

Figure 4 illustrates a top view of the arrangement shown in Figure 3;

Figure 5 illustrates a side view of the arrangement shown in Figure 3, whereby the integral laminated structure formed from the adhesive layer, peelable sacrificial surface layer covered by the adhesive layer, and the interposed marking have been peeled off the substrate so as to move marking therefrom; and

Figure 6 illustrates a side view of a substrate on which a peelable sacrificial surface layer has been reapplied subsequent to peeling the laminated structure.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term "marking", or grammatically equivalent terms thereof such as "markings", "mark", "marks", "marked" etc, is intended to mean a visible indication that presents on the surface of a substrate. The marking may be applied onto the substrate surface intentionally or unintentionally, and the marking may be authorised or unauthorised in the sense that a party responsible for the substrate has or has not, respectively, given permission for the substrate to be so marked. The marking may be a word, figure, symbol or design that is applied to the surface of the substrate using some form of marking means such as paint (e.g. spray paint), marking pen (e.g. felt tipped marker), pencil, crayon, lipstick, and the like. The marking may also be a substance such as mud, pollution, excrement (e.g. bird poo) that has deposited on to the surface of the substrate.

In one embodiment, the marking is graffiti. As used herein, the term "graffiti" is intended to mean an unwanted, undesirable and unauthorised word, figure, symbol or design (often referred to as a tag) that is applied to the surface of the substrate using some form of marking means such as paint (e.g. spray paint), marking pen (e.g. felt tipped marker), pencil, crayon, lipstick, and the like.

As used herein, the term "substrate" is intended to mean any object that may warrant protection from marking and can accommodate a peelable sacrificial surface layer on the part(s) thereof that is to be protected from marking. There is no particular limitation regarding the type of material from which the substrate may be formed. For example, the substrate may be formed from metal, glass, ceramic, plastic, stone, wood, etc, or combinations thereof. The part(s) of the substrate that is to be protected from marking will generally have a relatively flat or non-textured surface. In particular, the part(s) of the substrate that is to be protected from marking should be suitably adapted to receive the peelable sacrificial surface layer and for that layer to be peeled therefrom.

In one embodiment, the substrate is selected from a metal, plastic or timber panel.

In another embodiment, the substrate is selected from a road sign or an advertisement board.

The substrate may or may not have some form of coating applied thereto. For example, the substrate may be in the form of a panel of timber or a sheet of metal, or the substrate may be a panel of timber or sheet of metal onto which has been applied by any suitable means a desired design and/or written information (i.e. not graffiti). Accordingly, the term "substrate" is intended to not only embrace a structural object per se but also include a design or written information applied thereto by any suitable means, for example by painting, printing or application of printed material such as an adhesive sheet (e.g. sticker). From a practical point of view, the substrate will therefore include the material directly beneath the peelable sacrificial surface layer.

With reference to Figure 1 (presented as a side view), a substrate in accordance with the invention may be represented by features (5) and (10), with feature (5) more specifically representing, for example, a metal sheet of a road sign, and feature (10) more specifically representing, for example, relevant road sign information that has been applied to the metal sheet and which is to be protected from marking. A peelable sacrificial surface layer (15) is applied to the substrate (5, 10) in order to protect the outermost surface thereof (10) from graffiti.

There is no particular limitation regarding the nature of the sacrificial surface layer provided that it can be peeled off the substrate.

The peelable sacrificial surface layer may be coloured, opaque, transparent or clear. Generally, the sacrificial layer will be transparent or clear so that a design and/or written information on the substrate may be viewed through the layer. In another embodiment, the peelable sacrificial surface layer is clear.

The peelable sacrificial surface layer will generally be formed on the substrate by applying a suitable coating composition thereto. Coating compositions suitable for forming a peelable layer on the surface of a substrate are known. Such coating compositions can advantageously be used in accordance with the present invention. Examples of such coating compositions include polyurethane dispersions and blends of polyurethane and acrylic dispersions. Such dispersions may be aqueous dispersions (i.e. an aqueous polyurethane dispersion and a blend of aqueous polyurethane and aqueous acrylic dispersions).

Numerous commercially available polyurethane dispersions can advantageously be used to form the peelable layer used in accordance with the invention. A particular polyurethane dispersion will be selected according to its ability to be adequately peeled off a given substrate. This can be readily tested by those skilled in the art. Polyurethane dispersions are particularly suitable because the peelable layer they form can be relatively hard yet flexible, clear, non yellowing, UV resistant and water resistant. The resulting peelable layer can also have a high level of solvent resistance to minimise degradation when solvent based marking material is applied thereto.

Where a polyurethane dispersion is selected for use in forming the peelable sacrificial surface layer, it may have poor adhesion to a given substrate (i.e. it may too readily separate from the substrate). In that case, its adhesion to the substrate surface to be protected can be increased by blending the polyurethane dispersion with an acrylic dispersion. Where a blend of polyurethane and acrylic dispersions is employed, those skilled in the art will be able to determine the appropriate blend ratio to achieve the required level of adhesion.

If required, adhesion between the substrate surface to be protected and the peelable sacrificial surface layer can also be enhanced by coating that surface first with an acrylic dispersion. Such a coating composition is selected to be a permanent coating on the substrate and does not form part of the peelable sacrificial surface layer. Depending upon its requirements, this acrylic coating may be a clear, transparent, opaque or coloured coat. A polyurethane dispersion (or blend of polyurethane and acrylic dispersions) may then be applied to the acrylic coating layer to form the peelable sacrificial surface layer.

Coating compositions suitable for forming the peelable sacrificial surface layer will generally comprise additives such as surfactants, wet edge extenders, defoamers and preservatives commonly known in the art.

The coating composition used to form the peelable sacrificial surface layer may be solvent or aqueous based, be clear, transparent, opaque or contain one or more colorants.

In one embodiment, the coating composition used to form the peelable sacrificial surface layer is a clear aqueous coating composition. Suitable coating compositions that may be used to form the peelable sacrificial surface layer for use in accordance with the invention are sold by Vipond's Paints Pty Ltd (Australia). Where the peelable sacrificial surface layer is to be used in an outdoor application, it should be weather resistant and, if clear, it should undergo little or no yellowing.

Those skilled in the art will be able to select a suitable composition for use on a given substrate in order to ensure that the resulting sacrificial surface layer can be suitably peeled off the substrate.

In one embodiment, the method further comprises applying a coating composition to the substrate in order to form the peelable sacrificial surface layer. In a further embodiment, the coating composition used to form the peelable sacrificial surface layer is selected from an aqueous polyurethane dispersion and a blend of an aqueous polyurethane dispersion and an aqueous acrylic dispersion.

The coating composition used to form the peelable sacrificial surface layer may be applied to the substrate using conventional applicators of coating compositions. For example, the composition may be applied using a brush or roller applicator, or spray equipment. Those skilled in the art will be able to select the most appropriate application technique to use with a given substrate and under the conditions in which the coating composition is to be applied.

There is no particular limitation regarding the thickness of the peelable sacrificial surface layer. However, it will generally be applied as a relatively thin coating to minimise cost and to maximise application efficiency. It will also generally be desirable to make the peelable sacrificial surface layer as thin as possible where the layer is clear. Making such a layer as thin as possible will enhance the clarity of the coating. Generally, the peelable sacrificial surface layer will have a thickness ranging from about 10 microns to about 50 microns, for example from about 15 microns to about 35 microns. In one embodiment, the peelable sacrificial surface layer has a thickness of about 20 microns.

Upon applying the coating composition on to the surface of the substrate that is to be protected from markings, it will of course be necessary for the coating composition to dry or cure in order to form the peelable sacrificial surface layer. Those skilled in the art will be able to determine appropriate drying or curing times and conditions for a given coating composition and substrate.

It will be appreciated that where the method of the invention further comprises applying a coating composition to the substrate in order to form a peelable sacrificial surface layer thereon, it may be sometime before a marking is ultimately deposited on that layer. Accordingly, it may be some time before the step of applying an adhesive material onto the sacrificial surface layer and/or marking according to the method of the invention is performed.

In practice, it may be that a given substrate, for example a road sign, is manufactured and sold to an end user with the peelable sacrificial surface layer already in place. The end user may then put the substrate into service, for example by mounting a road sign at an appropriate location, and then monitor the sign for markings such as graffiti. Upon determining that a marking has occurred, the end user may then perform the method of the invention as outlined herein in order to remove the marking therefrom.

There is no particular limitation regarding the manner in which marking of the peelable sacrificial surface layer can occur. For example, graffiti is commonly applied using an aerosol paint can or felt tipped marker pen. Paint brush and roller application of paint are further techniques used to apply graffiti. Application of pollution, mud, bird poo and the like are to some extent dictated by other factors such as nature, weather and industrial activity etc. There is also no particular limitation regarding the composition of the marking. Generally, the graffiti will be derived from a solvent based paint (e.g. enamel), an aqueous based paint or an ink composition. Pollution, mud, bird poo and the like will have a varied composition.

With reference to Figure 2 (presented as a side view), the substrate (5,10) having a peelable sacrificial surface layer (15) illustrated in Figure 1 has had marking such as graffiti (20) applied to the peelable sacrificial surface layer (15).

Figure 3 illustrates the same side view as in Figure 2 except where an adhesive material has been applied onto the sacrificial surface layer (15) and marking (20) to form an adhesive layer (25). As can be seen from the Figure, at least some of the marking (20) is interposed between the adhesive layer (25) and the peelable sacrificial surface layer (15).

The adhesive layer (25), the peelable sacrificial surface layer (15) covered by the adhesive layer (25), and the interposed marking according to the present invention form an integral laminated structure. As will be discussed in more detail below, the laminated structure is subsequently peeled off the substrate so as to remove marking therefrom.

By the adhesive layer, peelable sacrificial surface layer covered by the adhesive layer, and the interposed marking forming an "integral laminated structure" is meant that the aforementioned components thereof form a sufficient bond there between that enables the laminated structure to be peeled off the substrate. Accordingly, it will be appreciated that the adhesive bond between the adhesive layer, peelable sacrificial surface layer covered by the adhesive layer, and the interposed marking will collectively be greater than the adhesive bond between the peelable sacrificial surface layer and the substrate. In other words, the peel off adhesive strength between the sacrificial surface layer and the substrate is lower than the peel off adhesive strength between (a) the adhesive layer and the sacrificial surface layer covered by the adhesive layer, and/or (b) the sacrificial surface layer covered by the adhesive layer and the marking applied thereto, and/or (c) the sacrificial surface layer covered by the adhesive layer, the marking applied thereto, and the adhesive layer, and/or (d) the adhesive layer and the marking applied to the sacrificial surface layer covered by the adhesive layer. By the "peel off adhesive strength" between the relevant components is meant a measure of the force required to peel a given component off another. Accordingly, the force required to peel the sacrificial surface layer off the substrate should be less than the force required to separate the components of the integral laminated structure. Relative peel off adhesive strength can be determined by simple qualitative testing. Alternatively, those skilled in the art will have a good understanding of more quantitative analytical techniques for determining peel off strengths.

Provided that the required peel off properties is attained, there is no particular limitation regarding the type of adhesive material that may be used in accordance with the invention. For example, the adhesive material may be in the form of a coating composition that is applied using an applicator (for example a brush, roller or aerosol) so as to form the adhesive layer. If suitable, the adhesive material may be applied in the form of a coating composition, the coating composition allowed to dry or cure so as to form the integral laminated structure, and the resulting integral laminated structure peeled off the substrate.

Alternatively, the adhesive material may be applied in the form of a coating composition onto which is applied a sheet material (e.g. a sheet of paper, plastic, cardboard or cloth etc) while the adhesive coating composition remain capable of bonding to the sheet material. For example, an adhesive coating composition such as glue may be applied onto a marked area of the sacrificial surface layer, and a sheet of paper and applied to the glue so as to in effect glue a sheet of paper to a marked area. In that case, the adhesive layer will be formed from both the glue and the sheet of paper. The adhesive material may also be conveniently provided in the form of a self-adhesive sheet of material such as an adhesive tape. It will be appreciated that a self-adhesive sheet material, such as adhesive tape, is made up of sheet material having an adhesive composition applied to a surface thereof. The self-adhesive sheet material may have a backing sheet that is first peeled away to reveal the adhesive surface of the sheet, thereby enabling the adhesive sheet to be applied in accordance with the invention. Alternatively, the self-adhesive sheet, such as an adhesive tape, may be in the form of a roll which when unrolled exposes an adhesive surface of the sheet which can then be applied in accordance with the invention.

Where a sheet material is used to form part of the adhesive layer, to facilitate adhesion between it and the peelable sacrificial surface layer and/or graffiti, it may be desirable to wipe over the surface of the applied sheet material using a flat edge such as a squeegee. In one embodiment, the adhesive material is a self-adhesive sheet.

It will generally be desirable that the adhesive material applied in accordance with the invention attains its required adhesive strength soon after application. Self-adhesive sheet materials are generally manufactured so as to satisfy this goal.

The type of adhesive material used in a given application may vary depending upon the type of peelable sacrificial surface layer used and/or the type of marking that has been applied thereon. Having said this, there are numerous commercial adhesive materials that have excellent adhesion to a wide variety of substrates. A person skilled in the art will readily be able to select a suitable adhesive material for use in accordance with the invention.

In one embodiment, the adhesive material is a self-adhesive sheet selected from self- adhesive packaging tape or self-adhesive vinyl.

In accordance with the invention, an adhesive material is applied onto the sacrificial surface layer and/or marking. In this context, the "and/or" is intended to mean that the adhesive material can be applied onto the sacrificial layer and marking, or just a section of marking that has been applied onto the sacrificial surface layer. As the adhesive material is applied to form an adhesive layer such that at least some of the marking is interposed between the adhesive layer and the peelable sacrificial surface layer, it will be appreciated that the adhesive material must at least be applied over some of the marking. However, it may be that the adhesive material is applied only over a section of marking that has itself been applied over the peelable sacrificial surface layer. For example, marking may have been applied over the entire surface of the peelable sacrificial surface layer. In that case, the adhesive material may not come into contact with the sacrificial surface layer per se, but rather contact the marking which in turn is in contact with the sacrificial surface layer.

The present invention can advantageously be used to remove in one peeling motion all or only part of the marking that has been applied to the peelable sacrificial surface layer. As to whether all or only part of the marking is removed in one peeling motion may depend upon the nature of the substrate and/or the surface area that can be covered by the adhesive material employed. For example, a contoured substrate may require the adhesive material to be applied in two or more separate applications, resulting in the need for two or more peeling motions to remove the marking. Alternatively, where a self-adhesive sheet material is used to form the adhesive layer, the sheet material may have insufficient surface area to cover the entire section of marking and thereby warrant two or more sheets to be applied.

Nevertheless, in order to perform the invention at least some of the marking will be interposed between the adhesive layer and the sacrificial surface layer and peeling the resulting integral laminated structure will result in at least some of the marking being removed from the substrate.

Having formed the integral laminated structure, it will be subsequently peeled off the substrate to remove marking therefrom. Peeling off the laminated structure is advantageously conducted using a standard peeling motion. Use of the adhesive material to form the adhesive layer over the surface of the peelable sacrificial layer affords a composite layered structure that imparts support to facilitate peeling off the sacrificial surface layer. In particular, the composite laminated structure advantageously enables the peelable sacrificial surface layer to be applied as a relatively thin layer that could otherwise not be readily peeled off the substrate without breaking. However, when such a thin layer forms part of the composite laminated structure it can be more readily peeled as a result of the backing support provided by the adhesive layer. Using a relatively thin peelable sacrificial surface layer can advantageously reduce cost, enhance transparency or clarity where the layer is transparent or clear, respectively, and decrease the drying/cure time of a coating composition applied to the substrate so as to form the layer. Depending upon where on the substrate the adhesive material is applied and/or the nature of the substrate, it may be that the so formed laminated structure can be peeled off the substrate with no additional steps. For example, the substrate may be a flat road sign having a peelable sacrificial surface layer applied onto the surface thereof. If marking has been applied to most of the peelable sacrificial surface layer, it may be desirable to remove the entire sacrificial surface layer from the substrate. In that case, a self adhesive sheet material having dimensions that cover the entire peelable sacrificial surface layer may be applied onto the surface thereof and the resulting integral laminated structure peeled off the substrate in one peeling motion to in effect leave behind the road sign with no peelable sacrificial surface layer (or marking) thereon. The sign may then be recoated with a coating composition to form a peelable sacrificial surface layer and the sign once again put back into service.

Alternatively, it may be that marking has only been applied onto part of the peelable sacrificial surface layer and it may not be desired to remove the entire layer. In that case, the adhesive material may be applied only to the relevant effected area of the peelable sacrificial surface layer. For example, Figure 4 illustrates a top view of Figure 3 showing the peelable sacrificial surface layer (15) onto only a part of which the marking (20) has been applied. The adhesive material (25) (showed transparent for the purpose of illustration only), is applied only onto the general marking affected section of the peelable sacrificial surface layer (15). To facilitate removal of only the peelable sacrificial surface layer that is covered by the adhesive layer, surface layer (15) may be scored only around the edge of the adhesive layer (30). For example, a sharp blade may be lightly pressed around the adhesive material edge (30). Upon peeling the resulting integral laminated structure off the substrate, it can then readily separate from sections of the sacrificial surface layer that have not been effected by marking.

In one embodiment, the peelable sacrificial surface layer is scored to facilitate peeling off the integral laminated structure from the substrate.

By the sacrificial surface layer being "scored" is meant that at least an indent is made in, or a cut is made through, the peelable sacrificial surface layer that enables only the peelable sacrificial surface layer covered by the adhesive material to be peeled off the substrate. Scoring can conveniently be performed using, for example, a box cutter blade or a scalpel blade. Figure 5 illustrates a side view of the integral laminated structure (25a, 20a, and 15a) being peeled off in a direction away from the substrate (35) so as to leave behind the substrate (5, 10) and a section of the sacrificial surface layer that was not covered by the now peeled adhesive layer (25a). As alluded to above, the integral laminated structure illustrated in Figure 5 is made up of a peeled sacrificial surface layer (15a), peeled marking (20a) and peeled adhesive layer (25a).

Once the integral laminated structure has been peeled off the substrate, the marking component thereof is of course removed from the substrate and the corresponding section of the substrate loses its protection from marking. However, a peelable sacrificial surface layer can be readily (re)applied as described herein to the exposed section of the substrate. Figure 6 is a side view of the substrate illustrated in Figure 5 where the integral laminated structure has been removed and a peelable sacrificial surface layer (15c) has been applied to the exposed section of the substrate. In Figure 6, (15) represents a section of peelable sacrificial surface layer that has not been removed in accordance with the present invention and (5, 10) represent the substrate.

After removing marking from the substrate, application of a coating composition to form peelable sacrificial surface layer on the exposed section of substrate can advantageously be done in a manner that for all practical purposes can hardly be distinguished from any peelable sacrificial surface layer that was not removed from the substrate (i.e. the newly applied layer can integrate well with the non-peeled layer).

The present invention also provides a kit for facilitating the removal of marking from a substrate. The kit comprises (1) a coating composition as described herein that when applied to a substrate forms a peelable sacrificial surface layer onto which marking can be applied, and (2) an adhesive material as described herein that when applied to a marking effected area of the sacrificial surface layer forms an adhesive layer, which together with the sacrificial surface layer that is covered by the adhesive layer and marking interposed there between forms an integral laminated structure. Peeling the laminated structure off the substrate removes marking therefrom as described herein.

The kit will generally further comprise instructions for performing the invention as described herein.

The present invention will hereinafter be described with reference to the following non- limiting examples.

EXAMPLES

Example 1 : Removal of marking from a road traffic sign

A road traffic sign measuring 450mm x 600mm having authorised written information and arrow symbols printed on the surface thereof was obtained. To the printed surface side of the road sign was applied a clear coat blend of polyurethane and acrylic dispersion obtained from Vipond's Paints Pty Ltd (Australia). The coating composition was applied to the road sign via spray equipment and air dried so as to afford a peelable sacrificial surface layer that was approximately 20 microns in thickness.

The resulting peelable sacrificial surface layer had excellent clarity and its presence was difficult to detect by eye. The applied coating composition became touch dry in about 30 minutes and was fully dried/cured in about 2 hours.

An enamel spray paint was then used to apply a marking in the centre of the road sign in the form of a "X" measuring about 10 cm ² . A self adhesive vinyl sheet obtained from Avery Graphics (MPI 3000) was then cut to size so that it fully covered the "X" marking in the centre of the sign (about 12 cm ² ). The backing sheet on the self-adhesive vinyl sheet was then removed and the adhesive surface of the vinyl sheet was applied over the entire marked area. A squeegee was then pressed over the surface of the applied adhesive layer to promote adhesion between it and the peelable sacrificial surface layer and marking.

A box cutter blade was then run around the entire perimeter of the applied adhesive layer so as to score the peelable sacrificial surface layer. The tip of the box cutter blade was used to lift a corner edge of the integral laminated structure formed from the adhesive layer, the peelable sacrificial surface layer covered by the adhesive layer and the marking interposed therebetween. The raised corner edge of the laminated structure was then grasped between two fingers and slowly peeled off the road sign to remove the marking therefrom and reveal a corresponding section of the road sign absent any peelable sacrificial layer protection. The same peelable coating composition outlined above was then applied to the entire road sign to again fully protect it from marking.

Example 2: Removal of marking from a real estate advertising board

A real estate advertising board (1800mm x 1200mm) was obtained having a digitally printed self adhesive vinyl sheet adhered to the surface thereof. The vinyl sheet had the relevant real estate information printed thereon and presented the surface that was to be protected from marking. To assist with adhesion of the peelable sacrificial surface layer, the surface of the board (i.e. the vinyl) was first coated with a clear aqueous acrylic dispersion obtained from Vipond's Paints Pty Ltd (Australia). The acrylic coating composition was applied via spray equipment and air dried. To this acrylic coated surface was applied a clear coat blend of polyurethane and acrylic dispersion obtained from Vipond's Paints Pty Ltd (Australia). The coating composition was applied to .the road sign via spray equipment and air dried so as to afford a peelable sacrificial surface layer that was approximately 20 microns in thickness.

The resulting peelable sacrificial surface layer had excellent clarity and its presence was difficult to detect by eye. The applied coating composition became touch dry in about 30 minutes and was fully dried/cured in about 2 hours.

An enamel spray paint was then used to apply a marking in the centre of the road sign in the form of a "ABC" measuring about 30 cm ² . A self adhesive vinyl sheet obtained from Avery Graphics (MPI 3000) was then cut to size so that it fully covered the "ABC" marking in the centre of the sign (about 40 cm ² ). The backing sheet on the self-adhesive vinyl sheet was then removed and the adhesive surface of the vinyl sheet was applied over the entire marked area. A squeegee was then pressed over the surface of the applied adhesive layer to promote adhesion between it and the peelable sacrificial surface layer and marking. A box cutter blade was then run around the entire perimeter of the applied adhesive layer so as to score the peelable sacrificial surface layer. The tip of the box cutter blade was used to lift a comer edge of the integral laminated structure formed from the adhesive layer, the peelable sacrificial surface layer covered by the adhesive layer and the marking interposed therebetween. The raised corner edge of the laminated structure was then grasped between two fingers and slowly peeled off the advertising sign to remove the marking therefrom and reveal a corresponding section of the sign absent any peelable sacrificial layer protection. The same peelable coating composition outlined above was then applied to the entire sign to again fully protect it from marking.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.