COATED FILM

Description

[0001] The present invention relates to a coated film for application to a surface to facilitate the removal of graffiti, paint and stickers from the surface, a method for producing such a coated film, the use of a coated film to improve the anti-graffiti, anti-stick and / or beading properties of a surface, and a traffic sign, wherein a coated film is applied at least to the front of the traffic sign.

[0002] Contamination from graffiti, paint smearing, felt-tip pen ink, and / or stickers on surfaces, for example in school restrooms or on traffic signs, is usually very difficult to remove and, if at all possible, only with strong organic solvents and / or considerable mechanical effort. At the same time, many of these surfaces cannot be easily replaced, or only at a significant cost and with additional material expenditure. However, such contamination must be removed promptly, especially from traffic signs, as they otherwise lose their validity. Municipalities and road maintenance departments therefore have to spend considerable time and money every year removing such contamination.Since cleaning is only possible using organic solvents, this requires trained personnel wearing personal protective equipment, and the organic solvents used must be completely contained and disposed of properly. Due to the very complex and costly cleaning process, it is usually decided to replace the traffic signs, as cleaning them is not worthwhile.

[0003] Protective coatings with non-stick properties are known from the state of the art.

[0004] EP 3 075 790 A2 describes a protective coating for an object, in particular for a sign, wherein the protective coating is applied as a transparent outer surface coating, characterized in that the protective coating has a surface with irregularly distributed dot-like protrusions, the protrusions being formed by particles arranged in a coating layer of the protective coating. While such a coating layer has good non-adherent properties for stickers, a disadvantage is that the protrusions can make it difficult to quickly and completely remove ink from felt-tip markers and / or graffiti. Furthermore, the use of an organic solvent is required for the complete removal of ink from felt-tip markers and / or graffiti.

[0005] DE 101 16 158 A1 describes a display sign or a display board, in particular a traffic sign or advertising board, with at least one display side coated with a non-stick layer made of plastic material with non-stick properties. This non-stick layer is intended to prevent the adhesion of snow, dirt, water and the like, thus avoiding the risk that the display information will no longer be legible due to such influences.

[0006] In their article "Fluoroalkyl Silane Modified Silicone Rubber / Nanoparticle Composite: A Super Durable, Robust Superhydrophobic Fabric Coating", Advanced Materials, 2012, Volume 24, No. 18, Hua Zhou et al. describe a superhydrophobic fabric coating made of a cross-linked polydimethylsiloxane elastomer containing well-dispersed hydrophobic silicon dioxide nanoparticles and fluorinated alkylsilane, exhibiting good resistance to repeated machine washing, heavy abrasion, strong acids or bases, boiling water or beverages, and excellent stain resistance.

[0007] In their article "Recent developments in the anti-graffiti coatings: an attentive review," Journal of Coatings Technology and Research, 2022, Vol. 19, No. 3, Amrutkar Shweta et al. describe various anti-graffiti coatings, including non-permanent, semi-permanent, and permanent coatings. They further describe how coatings containing fluorine and silicon dioxide nanoparticles exhibit particularly good anti-graffiti properties.

[0008] Furthermore, protective films or coatings with anti-graffiti or beading properties are already known in the prior art.

[0009] As a rule, protective coatings known from the prior art are time-consuming and / or expensive to produce. Furthermore, cleaning the surfaces is difficult, as organic solvents are usually required, at least to remove the ink from felt-tip markers and / or graffiti.

[0010] No protective coating or film is known in the prior art that simultaneously exhibits anti-graffiti, anti-stick, and beading properties. Against the background of the aforementioned prior art, the present invention was based on the objective of providing a coated film that at least partially overcomes one or more of the aforementioned disadvantages of the prior art. A coated film according to the invention should simultaneously exhibit anti-graffiti, anti-stick, and beading properties. In particular, the coated film according to the invention should significantly facilitate the removal of graffiti, paint smearing, felt-tip pen ink, and stickers from the surface, exhibit an improved beading effect compared to films of the prior art, and be manufactured simply and cost-effectively.For certain embodiments of the coated film according to the invention, particularly for use on traffic signs, the coated film according to the invention should also be transparent and not impair the reflective properties of an underlying layer. Finally, the transparent coated film according to the invention should be weather-resistant and UV-stable when used outdoors in order to obtain the CE marking required for use on traffic signs and to comply with the "ÖNORUM" standard for Austria and the "RAL" quality mark for Germany. The transparent coated film according to the invention should, in particular, possess the properties required for use on traffic signs in accordance with RAL-GZ 628 (May 2010 edition).

[0011] A further object of the present invention was to provide a method by which the coated film according to the invention can be produced with the described properties. In particular, the method should be fast and cost-efficient.

[0012] These problems are solved according to the invention by a coated film according to claim 1, a method according to claim 8, a use according to claim 13, and a traffic sign according to claim 15.

[0013] Advantageous embodiments of the invention are specified in the dependent claims and are explained in detail below.

[0014] The invention provides a coated film for application to a surface for the easier removal of graffiti, paint and stickers from the surface, comprising a plastic film and a coating arranged on the plastic film, wherein the coating contains a cross-linked liquid silicone rubber and wherein the coated film comprises an adhesive layer on the side of the plastic film facing away from the coating.

[0015] Surprisingly, it has been shown that the coated film according to the invention facilitates the removal of graffiti, paint smearing, felt-tip pen ink, and stickers from a surface treated with it. The coating of the film forms the outermost layer in contact with the contaminants. In particular, the aforementioned contaminants can be removed very easily from the coated film mechanically and / or with water. Furthermore, tests have shown that a coated film according to the invention exhibits an improved beading effect, meaning that in rain or high humidity, no or only very small water droplets form on such a surface, so that visibility according to the requirements of the certification authorities for traffic signs is not impaired. The surface tension of the coated film according to the invention has a value of less than 20 mN / m, measured according to DIN 53364.The coated film according to the invention can also be produced simply and cost-effectively and can be used flexibly to equip a wide variety of surfaces, for example made of metal, plastics, wood or composite materials.

[0016] Without wishing to be bound to scientific theories, the combination of advantageous properties of the coated film according to the invention appears to be attributable to the composition of the coating, in particular to the presence of cross-linked liquid silicone rubber in the coating. The coated film according to the invention comprises a coating arranged on a plastic film, wherein the coating contains a cross-linked liquid silicone rubber (LSR).

[0017] "Arranged on the plastic film," as used here, means that the coating is either in full contact with the plastic film or that there may be further layers between the coating and the plastic film.

[0018] Preferably, the coating of the coated film according to the invention contains the cross-linked liquid silicone rubber, based on the total weight of the coating, in an amount of at least 90 wt.%, in particular at least 95 wt.% or at least 99 wt.%. Particularly preferably, the coating of the coated film according to the invention consists of the cross-linked liquid silicone rubber.

[0019] According to a preferred embodiment, the cross-linked liquid silicone rubber contains polydimethylsiloxane, in particular the cross-linked liquid silicone rubber contains, based on the total weight of the cross-linked liquid silicone rubber, at least 50 wt.%, in particular at least 60 wt.% or at least 70 wt.% polydimethylsiloxane.

[0020] In addition to polydimethylsiloxane, the crosslinked liquid silicone rubber can contain up to 45 wt.%, preferably up to 35 wt.%, and particularly preferably up to 25 wt.% fillers. The fillers used can be those commonly known to those skilled in the art for liquid silicone rubber. Furthermore, the liquid silicone rubber can contain up to 5 wt.%, preferably 0.5 to 5 wt.%, and particularly preferably 0.5 to 1.5 wt.% additives. Preferably, crosslinkers, inhibitors, and / or catalysts are used as additives. A polymethylhydrogensiloxane is particularly preferred as the crosslinker, and an organoplatinum compound as the catalyst. According to another preferred embodiment, the crosslinked liquid silicone rubber is a crosslinked two-component silicone rubber, in particular a room-temperature crosslinking two-component silicone rubber.

[0021] The cross-linked liquid silicone rubber is preferably obtained by cross-linking such a room-temperature-curing two-component silicone rubber. Such liquid silicone rubbers are generally known to those skilled in the art and are commercially available, for example, under the trade name ELASTOSIL® RT from Wacker Chemie AG.

[0022] Preferably, the first component of the two-component silicone rubber contains a polydimethylsiloxane with crosslinkable end groups, preferably hydroxyl, amino, vinyl, and / or silanol end groups, particularly vinyl end groups, and a platinum-organic compound as a catalyst. The dynamic viscosity of the first component of the two-component silicone rubber is preferably between 4000 and 6000 mPas, determined at 23°C according to ISO 3219.

[0023] Preferably, the second component of the two-component silicone rubber contains a polymethylhydrogensiloxane, which acts as a crosslinker. The second component of the two-component silicone rubber preferably has a dynamic viscosity of 30 to 50 mPas, determined at 23 °C according to ISO 3219. Before mixing the second component of the two-component silicone rubber with the first component, an additional crosslinker can be added to accelerate the curing of the two-component silicone rubber. Such crosslinkers are known to those skilled in the art and are commercially available, for example, under the trade name ELASTOSIL® < CROSSLINKER 525. The amount of the additional crosslinker is typically between 1 and 5 wt.%, preferably between 2 and 4 wt.%, based on the total weight of the mixture of the first and second components of the two-component silicone rubber.Preferably, the crosslinking agent added to the second component of the 2-component silicone rubber is a hydrogen polysiloxane.

[0024] The cross-linked liquid silicone rubber is preferably obtained by mixing the two components of the two-component silicone rubber and cross-linking them. The mixing ratio of the first to the second component of the two-component silicone rubber is preferably set to 9:1. After mixing the two components, the mixture preferably has a pot life of more than 120 minutes, preferably more than 90 minutes. By adding an inhibitor to the first component of the two-component silicone rubber before mixing it with the second component, the pot life can be extended to 6 to 8 hours. Suitable inhibitors for this purpose are generally known to those skilled in the art and are commercially available. For example, the Wacker® inhibitors PT67 and PT88 from Wacker can be used. The amount of inhibitor is typically between 0.05 and 0.08 wt.%, preferably between 0.06 and 0.08 wt.%.-%, based on the total weight of the mixture of the first and second components of the two-component silicone rubber. The pot life can be lengthened or shortened by varying the amount of inhibitor. Increasing the amount of inhibitor increases the pot life. This also affects the curing time, which then also increases. Increasing the temperature significantly reduces the curing time again with a constant amount of inhibitor.

[0025] According to a particularly preferred embodiment, an inhibitor is added to the first component of the two-component silicone rubber before mixing it with the second component, and a further crosslinker is added to the second component before mixing it with the first component to optimize the pot life. An optimal pot life within the meaning of the invention means that the two-component silicone rubber partially cures at the optimal crosslinking temperatures and times specified below in connection with the inventive method, such that a coated film can be rolled up without sticking together. The complete curing of the two-component silicone rubber then takes place in the already rolled-up state of the coated film.

[0026] Furthermore, a solvent can be added to the first and / or second component of the two-component silicone rubber to optimize the viscosity and / or processing properties for coating. The solvent content can be up to 50 wt% based on the total amount of the first and second components of the two-component silicone rubber. Suitable solvents include, for example, xylene, toluene, white spirit, methyl ethyl ketone, and mixtures thereof. A mixture of methyl ethyl ketone and white spirit (Isopar™< E) in a 1:2 ratio is preferred. The solvents should be selected such that they ideally evaporate completely at the temperatures used for crosslinking the two-component silicone rubber. Small residual solvents may remain in the coating of the film according to the invention, which will evaporate over time.

[0027] The dynamic viscosity of the mixture of the first and second components of the 2-component silicone rubber is preferably between 500 and 4500 mPas, particularly between 3000 and 4000 mPas measured according to ISO 3219 at 23°C.

[0028] The curing of the two-component silicone rubber can take place at room temperature. The curing reaction is accelerated when temperatures above room temperature are used. Temperatures of 60 to 180 °C, particularly 70 to 150 °C or 80 to 130 °C, are preferably used to cure the two-component silicone rubber.

[0029] Tests have shown that the presence of a cross-linked liquid silicone rubber in the coating of the film according to the invention leads to the described advantageous properties, in particular anti-graffiti, anti-stick, and water-repellent properties. Furthermore, a cross-linked liquid silicone rubber results in a transparent coating without the addition of pigments. Such a transparent film according to the invention is particularly suitable for application to surfaces that are intended to be visible through the coated film, such as traffic signs. This was particularly surprising because it was not previously recognized in the prior art that liquid silicone rubbers are suitable for coating plastic films, as the liquid silicone rubbers used in the coating are generally employed as potting compounds for the production of molded articles by injection molding.

[0030] According to a preferred embodiment, the coating of the coated film according to the invention has a thickness of 0.5 µm to 250 µm, in particular 10 µm to 100 µm or 20 µm to 60 µm. Such a layer thickness enables the advantageous properties of the coated film according to the invention described above, in particular anti-graffiti, anti-stick, and beading properties. With a coating thickness below 0.5 µm, these advantageous properties are not achieved or are insufficiently achieved; conversely, a coating thickness of more than 100 µm is uneconomical, since an additional application of material does not lead to any further improvement in the properties and thus only generates higher costs.

[0031] The coated film according to the invention comprises a plastic film. Any plastic film known to those skilled in the art can be used as the plastic film, as long as it does not warp at the temperatures used for crosslinking the liquid silicone rubber present in the coating.

[0032] Preferably, the plastic film encompassed by the coated film according to the invention has a melting point above 150 °C, and in particular above 200 °C. For such a plastic film, it is ensured that it does not warp at elevated temperatures, to which the plastic film may be exposed, especially during the curing of the liquid silicone rubber. With a melting point of the plastic film below 150 °C, this cannot be guaranteed, meaning that the curing of the liquid silicone rubber would have to be carried out at lower temperatures, thus taking significantly longer and being less efficient.

[0033] However, it was found that the use of plastic films with a melting point below 150°C, such as acrylate films, is possible at the aforementioned high temperatures if the plastic film already has an adhesive layer and a release liner on the side not to be coated with the liquid silicone rubber, as described below. In such a case, the release liner, in particular, prevents the plastic film from warping. The release liner must, of course, be suitable for the aforementioned high curing temperatures of the liquid silicone rubber; that is, it must not warp itself.

[0034] It has proven particularly practical if the plastic film encompassed by the coated film is a polyester film, preferably a polyethylene terephthalate film, a polybutylene terephthalate film, or a polyethylene naphthalate film, especially a polyethylene terephthalate film. Such a plastic film has the advantage of being transparent and having a high melting point, so that the crosslinking of the liquid silicone rubber on the plastic film can occur at elevated temperatures, and the coated film, due to its transparency, is well suited for use in coating surfaces that are intended to remain visible through the coated film after application.

[0035] Preferably, the plastic film has a thickness of 10 µm to 500 µm, particularly 30 µm to 200 µm or 40 µm to 80 µm. Such a thickness ensures that the coated film possesses suitable mechanical properties for transport and its subsequent application to surfaces, particularly with regard to tensile strength, elasticity, and tear resistance. A thickness of less than 10 µm results in a coated film that is not sufficiently stable and tears even under slight mechanical stress. It has been found that a thickness of more than 500 µm, particularly more than 200 µm, does not lead to any further improvement in the mechanical properties of the coated film according to the invention for use and transport. Therefore, greater thicknesses are disadvantageous for economic reasons, as more material than necessary is used.

[0036] The actual thickness of the plastic film used in the coated film according to the invention can be further optimized for the respective application. For embodiments of the coated film according to the invention that are intended to be applied to a surface, such as a wall, partition, door, etc., in order to impart the advantageous properties of the coated film according to the invention, a thickness of approximately 80 µm to 300 µm has proven particularly practical. For embodiments of the coated film according to the invention that are intended to coat a surface that should be clearly visible through the coated film after its application, such as the front of a traffic sign, significantly lower thicknesses, for example between 10 and 70 µm, are also suitable.

[0037] The coated film according to the invention can comprise further layers.

[0038] According to a preferred embodiment, the coated film between the plastic film and the coating comprises a primer, in particular a cross-linked primer for silicone rubber, which contains siloxanes and / or silanes cross-linked with the cross-linked liquid silicone rubber. Such primers are generally known to those skilled in the art and are commercially available, for example, under the trade name WACKER® PRIMER G from Wacker Chemie AG.

[0039] Preferably, the primer, prior to crosslinking, can be a solution of reactive siloxanes and / or silanes in an organic solvent. This solution is preferably applied to at least a portion of the plastic film during the production of the coated film. As the solvent evaporates and under atmospheric humidity, a solid primer can form, which is firmly bonded to the plastic film. After the liquid silicone rubber is applied to the primer, the reactive siloxanes and / or silanes can crosslink with the liquid silicone rubber. This ensures particularly good adhesion between the plastic film and the coating.

[0040] According to an alternative embodiment of the coated film according to the invention, the plastic film is siliconized, i.e. functionalized with silicone groups, in order to further improve the adhesion of the coating to the plastic film of the coated film according to the invention, without the need for a primer between the plastic film and the coating.

[0041] To achieve an additional improvement in adhesion between the plastic film and the coating, the coated film can have a primer between the plastic film and the coating, and the plastic film can also be siliconized.

[0042] The coated film according to the invention comprises an adhesive layer on the side of the plastic film facing away from the coating. An "adhesive layer" as used here is a layer that consists of or comprises adhesive. Commercially available adhesives known to those skilled in the art can be used. It is self-evident that the type of adhesive depends on the type of plastic film and the surface to which the coated film is to be applied. The adhesive can, in particular, be selected from acrylate adhesives, especially cyanoacrylate or methyl methacrylate adhesives, polyurethane adhesives, or epoxy adhesives. Such an adhesive layer serves to equip the coated film in such a way that it can be adhered to a surface.Depending on the type of adhesive, it can either be activated by heat and the coated film is laminated onto a surface, or the adhesive is self-adhesive, so that simply pressing the coated film onto the surface is sufficient for it to adhere to the surface.

[0043] According to a further embodiment of the invention, the coated film comprises a release liner on the side of the adhesive layer facing away from the plastic film. This embodiment is particularly advantageous when using self-adhesive adhesives in the adhesive layer to prevent the coated film from sticking together during rolling and transport. The release liner can be removed before the coated film is used at the point of application, and the coated film can then be adhered to a surface. The release liner can advantageously have an embossed surface that is transferred to the adhesive layer. Such an embossed surface of the release liner can, for example, prevent air pockets from forming under the coated film when it is applied to a surface.

[0044] Preferably, the coated film has the following layer structure from one side to the opposite side: optionally release paper, adhesive layer, plastic film, optionally primer, coating. After the coated film according to the invention is applied to the surface to be coated, the coating forms the visible side and is in contact with any soiling that may need to be removed, such as graffiti, paint, and stickers.

[0045] According to a preferred embodiment of the coated film according to the invention, all layers of the coated film are transparent to electromagnetic waves with wavelengths from 400 nm to 780 nm. When the coated film according to the invention is completely transparent, underlying surfaces provided with this transparent coated film, for example, the fronts of traffic signs, are visible through the transparent coated film without impairing their legibility or visibility. In particular, the transparent coated film meets the requirements for the specific retroreflective value according to section 12.25 of RAL-GZ 628 for traffic signs and traffic control devices (May 2010 edition) as well as the other requirements specified in RAL-GZ 628.

[0046] According to an alternative embodiment of the coated film according to the invention, at least one layer of the coated film can contain pigments. A layer containing pigments, as defined by the invention, is no longer transparent but opaque. The pigments contained in the at least one layer of the coated film according to the invention can be organic and / or inorganic. The pigments can, for example, be selected from the group consisting of titanium dioxide, iron oxide yellow, bismuth vanadate, rutile tin-zinc, iron oxide red, cobalt blue, ultramarine blue, chromium oxide green, cobalt green, carbon black, iron oxide black, and mixtures thereof. The inclusion of pigments in the at least one layer of the coated film results in colored, non-transparent coated films that, depending on the pigment, can cover desired areas of the color spectrum.Such colored coated films can be used, for example, to cover surfaces soiled and / or damaged by the aforementioned contaminants, so that they appear to have the color of the coating. Applying the colored coated film completely covers the underlying soiling and / or damage on the surface, thus preventing the soiling and / or damage from showing through. A further advantage is that such a surface with the applied colored coated film exhibits the beneficial properties, particularly anti-graffiti, anti-stick, and water-repellent properties, of the coated film according to the invention and can be easily cleaned, while prior cleaning and / or repair of the soiled and / or damaged surface is unnecessary.In particular, it is sufficient to apply the colored coated film according to the invention to the surface in order to achieve the impression of a new surface.

[0047] Alternatively, the transparent coated film according to the invention can be used to cover soiled and / or damaged surfaces by first laminating it onto an opaque colored plastic film and then applying the composite of the transparent coated film according to the invention, together with the opaque colored plastic film, to the object to be covered. Opaque in the sense of the invention means non-transparent. An advantage of this alternative is that the opaque colored plastic film does not have to meet the curing temperature requirements mentioned above for the plastic film in the coated film according to the invention and can therefore be freely selected.

[0048] The invention further provides a method for producing a coated film according to the invention, comprising the following steps: i. Providing a plastic film; ii. Applying a liquid silicone rubber to one side of the plastic film; iii. Cross-linking the liquid silicone rubber. b. Applying an adhesive layer to the side of the plastic film to which the liquid silicone rubber is not applied.

[0049] Using such a process, a coated film according to the invention with the described properties can be produced. In particular, such a process can be carried out quickly and cost-effectively. It goes without saying that the specifications described above for the design of the coated film according to the invention apply analogously to the process according to the invention.

[0050] The method according to the invention comprises in step i. the provision of a plastic film. The plastic film can be designed as described in detail above in connection with the coated film according to the invention.

[0051] According to step ii of the inventive method, a liquid silicone rubber is applied to one side of the plastic film. The liquid silicone rubber can be configured as described in detail above in connection with the coated film according to the invention.

[0052] According to the invention, the liquid silicone rubber is applied to exactly one side of the plastic film. This allows the two sides of the plastic film to have different properties; for example, the side coated with the liquid silicone rubber can have anti-graffiti, anti-stick, and beading properties, while the other side has adhesive properties and / or can be modified with further layers.

[0053] The application of the liquid silicone rubber to one side of the plastic film in step ii is preferably carried out on more than 90%, and in particular more than 95%, of the surface of that side of the plastic film. It is especially preferred that the liquid silicone rubber be applied to the entire surface of that side of the plastic film. This ensures uniform surface properties on the side of the plastic film to which the liquid silicone rubber has been applied.

[0054] In step iii. of the inventive method, the Liquid Silicone Rubber applied to at least one side of the plastic film is crosslinked.

[0055] According to a preferred embodiment of the inventive process, crosslinking in step iii takes place at a temperature of 80 to 200 °C, particularly at 100 to 160 °C or 140 to 150 °C. Such a temperature enables rapid crosslinking of the liquid silicone rubber. This allows the process to be carried out quickly and efficiently. A temperature below 80 °C significantly increases the time required for crosslinking and is therefore less efficient. A temperature above 180 °C carries the risk of the plastic film warping.

[0056] Particularly preferably, the crosslinking in step iii. takes place at the aforementioned temperatures for a period of 12 s to 10 min, more preferably 30 s to 5 min, or 1 to 2 min before the coated film is rolled up. A duration of less than 12 s is insufficient for adequate crosslinking to allow the coated film to be rolled up without the surface of the coated film sticking to the underside of the coated film in the roll. A duration that is too long, more than 10 min, is uneconomical. Surprisingly, it has been found that it is possible to partially cure the coating to such an extent that the coated film can be rolled up without sticking, and that crosslinking continues even after cooling and rolling up the coated film.

[0057] According to a preferred embodiment of the method according to the invention, the method prior to step ii. further comprises the following step: a. Treat the side of the plastic film to which the Liquid Silicone Rubber will be applied in step ii. with a primer.

[0058] Such treatment with a primer enables improved adhesion of the liquid silicone rubber to the plastic film, since they can be chemically bonded to one another during crosslinking in process step iii. The primer can be designed as described in detail above for the coated film according to the invention. However, the plastic film can alternatively or additionally be provided as a siliconized plastic film in step i of the process according to the invention; in this case, applying a primer to improve adhesion is not strictly necessary or is further enhanced.

[0059] The method according to the invention further comprises the following step: b. Applying an adhesive layer to the side of the plastic film to which the liquid silicone rubber is not applied.

[0060] What has been said in connection with the coated film according to the invention regarding the adhesive layer applies analogously to the adhesive layer of the method according to the invention.

[0061] According to a further embodiment of the invention, the method comprises the following step: c. Applying a release paper to the plastic film, in particular to the side of the plastic film to which the liquid silicone rubber is not applied.

[0062] What has been said in connection with the coated film for the release paper according to the invention applies analogously to the release paper of the method according to the invention.

[0063] Steps b. and c. can also take place simultaneously by using a release paper already coated with an adhesive layer and applying it with the adhesive side to a plastic film, in particular to the side of the plastic film to which the liquid silicone rubber is not applied.

[0064] The process steps of the method according to the invention can take place in any order convenient for a person skilled in the art, starting from step i. Preferably, the process steps of the method according to the invention take place in the following sequence: step i., optionally step a., step ii., step iii., step b., optionally step c., or optionally step b. and step c. simultaneously. Alternatively, the process steps can also take place in the following order: step i., step b., optionally step c., or optionally step b. and step c. simultaneously, optionally step a., step ii., step iii.

[0065] The invention further relates to the use of a coated film according to the invention or a coated film according to the invention produced according to a method according to the invention for improving the anti-graffiti, anti-stick and / or beading properties of a surface.

[0066] To clean such a surface of dirt, only light mechanical force and / or tap water are required; no organic solvents are needed. The surface can then be cleaned, for example, with a cloth, a pressure washer, or, if graffiti needs to be removed, with adhesive film, such as a lint roller or a clothes roller with adhesive tape on a roll.

[0067] According to a preferred embodiment of the use according to the invention, the surface is a surface made of metal, plastic, wood and / or composite material. Particularly preferred is the front of a traffic sign.

[0068] It goes without saying that the film according to the invention can be designed for the use according to the invention in such a way as has been described above in connection with the film according to the invention.

[0069] Finally, the invention relates to a traffic sign, wherein at least on the front of the traffic sign a transparent coated film according to the invention or a transparent coated film according to the invention produced according to the inventive method is applied such that the coating forms the outermost layer when viewed from the traffic sign. Such a traffic sign has the advantageous properties described above; in particular, graffiti, paint smearing, felt-tip pen ink, and stickers can be easily removed, and the traffic sign exhibits a water-repellent effect and good weather resistance. Additionally, the transparent coated film according to the invention fulfills the official requirements for the transmission of reflective rays and light intensity of traffic signs, and the traffic sign is easily legible.The traffic sign can additionally be coated on its reverse side with a transparent or colored coated film according to the invention. The reverse side of the traffic sign is the side facing away from the viewer, i.e., the side of the traffic sign on which the traffic sign has no markings. This allows the advantageous properties of the coated film according to the invention to be maintained on the reverse side of the traffic sign as well.

[0070] The principle of the invention will be explained in more detail below using examples that do not restrict the subject matter of the invention, with reference to the three figures. Fig. 1 Schematic representation of an embodiment of a (non-inventive) coated film. Fig. 2 Schematic representation of an alternative embodiment of a (non-inventive) film. Fig. 3 Schematic representation of an embodiment of the coated film according to the invention.

[0071] Figure 1 Figure 1 schematically shows an embodiment of a coated film 1 (not according to the invention). The coated film 1 comprises a plastic film 2 with a coating 3 arranged thereon. The coating contains a liquid silicone rubber (not shown in the figure). Such a coated film can be produced as described in Example 1 and is suitable, for example, for being laminated onto a surface.

[0072] In Figure 2An alternative embodiment of a coated film 1 is shown schematically. The coated film 1 comprises a plastic film 2 with a coating 3 arranged on it. A primer 4 is located between the plastic film 2 and the coating 3. This embodiment of the coated film 1 can be produced as described in Example 2 and is suitable, for example, for being laminated onto a surface using pressure and heat.

[0073] Figure 3Figure 1 schematically shows an embodiment of a coated film 1 according to the invention. The coated film 1 according to the invention comprises a plastic film 2 with a coating 3 arranged thereon. A primer 4 is located between the plastic film 2 and the coating 3. An adhesive layer 5 is located on the side of the plastic film 2 facing away from the coating 3. A release paper 6 is arranged on the adhesive layer. Such a coated film 1 can be applied to a surface by peeling off the release paper 6 using the adhesive layer 5 and adheres to it. Examples of implementation Materials used:

[0074] Coating: 2-component silicone rubber ELASTOSIL® < RT 601 A / B Inhibitor: WACKER ®< INIBITOR PT88 Another networker: ELASTOSIL® < NETWORKER 525 Primer: WACKER ®< PRIMER G 790 Toluene-free Plastic film: Polyethylene terephthalate film with a thickness of 30 µm or 60 µm Adhesive layer: Henkel Lactite-Duro-Tak 151A acrylate adhesive Example 1: Production of a coated film with the layer structure plastic film / Coating (see Fig. 1) (not according to the invention)

[0075] A polyethylene terephthalate film with a thickness of 60 µm was prepared. Subsequently, 9 parts by weight of the first component of the two-component silicone rubber ELASTOSIL®< RT 601 A, containing polydimethylsiloxane with vinyl end groups and a platinum-organic compound as a catalyst, as well as fillers, were mixed separately with 0.075 wt% of the inhibitor, based on the total amount of the first and second components. Then, 1 part by weight of the second component, ELASTOSIL®< RT 601 B, containing a polymethylhydrogensiloxane, was mixed with 3 wt% of the additional crosslinker, based on the total amount of the first and second components. The two resulting mixtures were then blended together, and this blend was applied to one side of the polyethylene terephthalate film to a thickness of approximately 50 µm. The film was then heated in an oven at 150 °C for 90 seconds.When the film was removed from the oven, the 2-component silicone rubber had sufficiently hardened and was firmly bonded to the film, so that the coated film could be rolled up without difficulty. Example 2: Production of a coated eolite with the layer structure of plastic film / Primer / coating (see Fig. 2) (not according to the invention)

[0076] A polyethylene terephthalate (PET) film with a thickness of 30 µm was prepared. A solution of reactive siloxanes and silanes in an organic solvent was then applied thinly (approximately 5 µm layer thickness) to one side of the PET film as a primer. The film was then left to stand for one hour at room temperature and 40% relative humidity. During this time, the organic solvent evaporated, forming a primer that bonded firmly to one side of the PET film. Subsequently, 9 parts by weight of the first component of the two-component silicone rubber ELASTOSIL®< RT 601 A, containing polydimethylsiloxane with vinyl end groups and a platinum-organic compound as a catalyst, as well as fillers, were applied separately at a concentration of 0.075 wt.-% of the inhibitor, based on the total amount of the first and second components, was mixed, and one part by weight of the second component, ELASTOSIL® RT 601 B, containing a polymethyl hydrogen siloxane, was mixed with 3% by weight of the additional crosslinker, based on the total amount of the first and second components. The resulting two separate mixtures were then blended and applied to the side of the polyethylene terephthalate film to which the primer had been applied, in a thickness of approximately 50 µm. The film was then heated in an oven at 150 °C for 90 seconds. Upon removal of the film from the oven, the two-component silicone rubber had sufficiently cured and the three layers were sufficiently bonded to allow the coated film to be rolled up without difficulty. Example 3: Production of a coated film with a layered structure of release paper / adhesive layer / plastic layer / primer / coating (see Fig. 3)

[0077] A polyethylene terephthalate (PET) film with a thickness of 60 µm was prepared. A solution of reactive siloxanes and silanes in an organic solvent was then applied thinly (approximately 5 µm layer thickness) to one side of the PET film as a primer. The film was then left to stand for one hour at room temperature and 40% relative humidity. During this time, the organic solvent evaporated, forming a primer that bonded firmly to one side of the PET film. Subsequently, 9 parts by weight of the first component of the two-component silicone rubber ELASTOSIL®< RT 601 A, containing polydimethylsiloxane with vinyl end groups and a platinum-organic compound as a catalyst, as well as fillers, were applied separately at a concentration of 0.075 wt.-% of the inhibitor, based on the total amount of the first and second components, was mixed, and one part by weight of the second component, ELASTOSIL® RT 601 B, containing a polymethyl hydrogen siloxane, was mixed with 3% by weight of the additional crosslinker, based on the total amount of the first and second components. The resulting two separate mixtures were then blended and applied to the side of the polyethylene terephthalate film to which the primer had been applied, at a thickness of approximately 50 µm. The coated film was heated in an oven at 150 °C for 90 seconds. Upon removal of the coated film from the oven, the two-component silicone rubber had sufficiently cured, and the three layers were firmly bonded together. An acrylate adhesive was applied to the side of the coated film not coated with the silicone rubber. Finally, a release liner was applied over the acrylate adhesive.The coated film was then rolled up. Example 4: Applying a coated film to the front of a traffic sign (not according to the invention)

[0078] A coated film produced according to Example 2 was laminated onto the front of a traffic sign using pressure and heat.

[0079] Subsequently, the optical properties, the anti-graffiti, the anti-stick and the beading properties of the front of the traffic sign covered with the coated film were examined.

[0080] No impairment of the legibility and reflective properties of the surface of the traffic sign with the coated film was observed compared to the front of a traffic sign without coated film.

[0081] A sticker was affixed to the front of the traffic sign. This sticker barely adhered to the surface and could be easily removed by peeling it off the sign.

[0082] The front of the traffic sign was written on with a permanent marker (edding® < 3000 permanent marker). It turned out that the ink beaded up and was almost impossible to write on. The ink could be easily removed with water or simply by wiping it with a cloth.

[0083] Finally, the front surface was moistened using a water atomizer to examine its beading properties. The sprayed water completely beaded off the surface.

[0084] In the As a result, the traffic sign provided with the coated film according to the invention fulfills all requirements according to RAL-GZ 628 (edition May 2010) for traffic signs and traffic control devices and also has anti-graffiti, beading and anti-stick properties.

Claims

1. Coated film for application to a surface for easier removal of graffiti, paint and stickers from the surface, comprising a plastic film and a coating arranged on the plastic film, wherein the coating contains a crosslinked liquid silicone rubber and wherein the coated film comprises an adhesive layer on the side of the plastics film facing away from the coating.

2. Coated film according to claim 1, characterized in that the plastic film has a thickness of 10 µm to 500 µm, in particular 30 µm to 200 µm or 40 µm to 80 µm.

3. Coated film according to claim 1 or 2, characterized in that the plastic film is a polyester film, in particular a polyethylene terephthalate film, a polybutylene terephthalate film or a polyethylene naphthalate film, in particular a polyethylene terephthalate film.

4. Coated film according to any of the preceding claims, characterized in that the coating has a thickness of 0.5 to 250 µm, in particular 10 µm to 100 µm or 20 to 60 µm.

5. Coated film according to any of the preceding claims, characterized in that the crosslinked liquid silicone rubber contains polydimethylsiloxane, in particular that the crosslinked liquid silicone rubber contains at least 50 wt.%, in particular at least 60 wt.% or at least 70 wt.% polydimethylsiloxane based on the total weight of the crosslinked liquid silicone rubber in each case.

6. Coated film according to any of the preceding claims, characterized in that the crosslinked liquid silicone rubber is a crosslinked 2-component silicone rubber, in particular a crosslinked 2-component silicone rubber which crosslinks at room temperature.

7. Coated film according to any of the preceding claims, characterized in that the coated film comprises a primer between the plastic layer and the coating.

8. Method for producing a coated film according to any of claims 1 to 7, comprising the following steps: i. providing a plastic film; ii. applying a liquid silicone rubber to one side of the plastic film; iii. crosslinking the liquid silicone rubber; b. applying an adhesive layer to the side of the plastic film to which the liquid silicone rubber is not applied.

9. Method according to claim 8, characterized in that the application of the liquid silicone rubber comprises a step of mixing a polydimethylsiloxane with crosslinkable end groups, preferably hydroxyl, amino, vinyl, and / or silanol end groups, in particular vinyl end groups, an organoplatinum compound, a polymethyl hydrogen siloxane, and optionally fillers.

10. Method according to claim 8 or 9, characterized in that the crosslinking in step iii. takes place at 60 to 180 °C, in particular at 70 to 150 °C or 80 to 130 °C.

11. Method according to any of claims 8 to 10, characterized in that the crosslinking in step iii. takes place over a period of 12 s to 10 min, in particular from 30 s to 5 min, more preferably from 1 to 2 min.

12. Method according to any of claims 8 to 11, characterized in that the method comprises the following step prior to method step ii.: a. siliconizing the side of the plastic film onto which the liquid silicone rubber is applied in step ii.; and / or treating the side of the plastic film to which the liquid silicone rubber is applied in step ii. with a primer.

13. Use of a coated film according to any of claims 1 to 7 or a coated film produced according to a method according to any of claims 8 to 12 for improving the anti-graffiti, anti-stick and / or beading properties of a surface.

14. Use according to claim 13, characterized in that the surface is a surface made of metal, plastic material, wood and / or composite material, in particular the front of a traffic sign.

15. Traffic sign, wherein a coated film according to any of claims 1 to 7 or a coated film produced according to a method according to any of claims 8 to 12 is applied at least on the front side of the traffic sign such that the coating, as seen from the traffic sign, forms the outermost layer.