Method of applying adhesive film

Abstract

In a method of applying an adhesive film (10) to a surface (20) of a component, an adhesive film (10) comprising an adhesive layer (11) is provided. Furthermore, a component comprising the surface (20) to be bonded is provided. The adhesive layer (11) of the adhesive film (10) is physically surface-activated. The adhesive layer (11) of the adhesive film (10) is wetted before the surface-activated and wetted adhesive film (10) comes into contact with the surface (20) of the component to be bonded.

Description

Technical Field

[0001] The present invention relates to a method for applying an adhesive film to the surface of a component and an apparatus suitable for carrying out this method. Background Technology

[0002] Adhesive films are used in many fields, such as for decoration, like transferring color patterns onto surfaces, or for functional reasons, such as acting as a protector for painted surfaces, or for applying lettering and the like. Adhesive films are increasingly used, particularly in the mass production of motor vehicles, for example, as falling object protection devices, for applying model names and the like, and of course, for exterior design.

[0003] Generally speaking, the cost of applying color patterns using adhesive film is far lower than the cost of creating such patterns using a multi-stage painting process. However, applying adhesive film in mass production is not easy. The larger the adhesive film, the more difficult it is to position it correctly on the surface to be bonded and to bond it without bubbles and wrinkles. To date, automation of these processes has not been achieved. Therefore, for example, in the mass production of motor vehicles, adhesive film has typically been applied manually until now.

[0004] US 6197397 B1 discloses adhesive films that include microstructured channels located within the adhesive layer. These channels allow air to escape during adhesive film application, thus preventing bubble formation and eliminating the need for manual finishing to remove bubbles. Therefore, compared to conventional adhesive films without microstructured channels, the aforementioned adhesive film is more suitable for automated processing.

[0005] However, these types of adhesive films are very expensive. Furthermore, the microstructured adhesive layers make them unsuitable for forming high-quality surfaces. Adhesive films typically consist of a carrier film, one side of which is covered by the adhesive layer, and the other side by, as appropriate, multiple layers of varnish. When using very thin carrier films, the microstructure remains visible even after adhesion. Generally, very thick adhesive films are undesirable, although thick films can solve the problem. However, these thick films bulge significantly onto the substrate. Without a clear coat to cover them, satisfactory results are difficult to achieve.

[0006] WO 2020 / 148070 A1 discloses a method and tool for applying an adhesive film to the surface of a workpiece or component, which solves the aforementioned problem. To this end, an automated system positions an adhesive film containing an adhesive layer between the surface to be bonded and an elastic diaphragm. Due to a negative pressure applied between the diaphragm and the surface, the diaphragm arches towards the surface with both convex and concave sides until it contacts the surface with the convex layer facing forward, thereby pressing the adhesive layer of the adhesive film evenly onto the surface through the diaphragm. Here, the arching of the diaphragm is adjusted by adjusting the pressure conditions on both sides of the diaphragm. Accordingly, for example, the arching of the diaphragm caused by the applied negative pressure can be supported by a corresponding overpressure on the back side of the diaphragm.

[0007] The problem with these traditional methods may be that the adhesive film does not adhere sufficiently to the workpiece or component during the film application process. Even if the insufficient adhesion is only present in the partition between the adhesive film and the workpiece, it can still lead to undesirable bubbles and cavitation.

[0008] For example, in the process of manufacturing motor vehicles, when applying adhesive films, it is often helpful to wet the adhesive layer of the film with water before positioning it on the surface to be bonded. This wetting operation is usually done manually, where it is difficult to measure the amount of water precisely. In this case, the problem of applying too much water often occurs, causing water to flow laterally from the contact area between the adhesive film and the surface after the adhesive film is applied, resulting in uneven adhesion or causing the adhesive film to slip. Summary of the Invention

[0009] In view of this, the purpose of the invention described below is to provide an improved method and an improved apparatus for applying adhesive film to components. The objective is particularly to develop an automated method and apparatus for applying adhesive film, which can be integrated into mass production, such as into a production line for manufacturing motor vehicles.

[0010] The present invention provides a solution for achieving the above-mentioned objective as a method having the steps described in claim 1, and an apparatus having the features described in claim 7. Further embodiments of the invention are described in the dependent claims.

[0011] The method of applying an adhesive film to the surface of a component according to the present invention always includes the following steps:

[0012] a. Provide an adhesive film containing an adhesive layer.

[0013] b. Provide a component containing the surface to be bonded.

[0014] c. Perform physical surface activation of the adhesive layer of the adhesive film.

[0015] d. Wet the adhesive layer of the adhesive film.

[0016] e. To bring the surface-activated and wetted adhesive film into contact with the surface of the component to be bonded.

[0017] This invention discovers that by combining the physical surface activation of the adhesive layer of the adhesive film with subsequent wetting of the adhesive layer before bringing the surface-activated and wetted adhesive film into contact with the surface to be bonded, the bonding process or application of the adhesive film can be significantly improved and simplified. This method, in particular, enables the adhesive film to be applied to the component very uniformly without the generation of bubbles, irregularities, or other undesirable inaccuracies during the application process. The method of this invention, especially, allows for optimal wetting of the adhesive layer without applying too little or too much moisture.

[0018] According to the present invention, it is preferable to apply a uniform and thin water film to the adhesive layer after surface activation for wetting. This compensates for irregularities in the adhesive layer, thereby achieving a very uniform bonding result. In principle, aqueous solutions or suspensions can also be used for wetting. Organic solvents or solvent-water mixtures can also be used instead of water in principle, but this is generally not a preferred approach.

[0019] When targeted roughening of the adhesive side of an adhesive film is performed to improve adhesion, wetting after surface activation is particularly preferred. In many cases, only by wetting the adhesive layer can the roughened adhesive side of the film be satisfactorily adhered in a uniform and flawless manner. In this invention, the adhesive layer is physically surface-activated first, so wetting can be optimized as needed. Based on this method, capillary action in the adhesive layer can be advantageously utilized to apply the adhesive film to various surfaces in a bubble-free manner.

[0020] Another particular advantage of the method of the present invention is its ease of automation. In this regard, the method of the present invention can be particularly advantageously applied, for example, to the manufacture of motor vehicles. Conventionally, when applying adhesive films, such as labels, to the painted surface of a motor vehicle body, the adhesive side of the adhesive film is manually wetted before application. In this case, it is difficult to achieve uniform wetting without applying too much or too little water, resulting in unsatisfactory adhesion. Furthermore, the required personnel costs are very high. The method of the present invention solves these problems.

[0021] Physical surface activation of the adhesive layer specifically increases the surface energy within the adhesive layer. This has been observed to improve the wettable properties of the adhesive layer. Surface activation particularly leads to the disintegration of the molecular structure within the adhesive layer. By activating the adhesive layer, especially inducing hydrophilic properties of the surface, it facilitates wetting with water or aqueous solutions. Typically, this activated or excited state of the surface is short-lived; therefore, after a certain period, such as about 30 minutes or, depending on the circumstances, the molecular structure returns to its initial state. Therefore, after surface activation, steps d. and e. of the method of the present invention are preferably carried out within a limited time period. Preferably, the time elapsed between the physical surface activation of the adhesive layer and subsequent wetting, until the adhesive film comes into contact with the surface of the component, should not exceed 30 minutes. In a particularly preferred embodiment, the entire process of surface activation, wetting, and contact does not exceed 20 minutes, even more preferably not exceeding 10 minutes, and particularly not exceeding 5 minutes.

[0022] The surface energy of a substrate is usually expressed as energy per unit area, in units of J / m². 2 The equivalent units N / m or dyn / cm are often used. Preferably, a surface energy of ≥50 dyn / cm, particularly preferably ≥60 dyn / cm, and especially preferably ≥70 dyn / cm is achieved through physical surface activation according to the method of the invention. The inventors have pointed out that, particularly when the surface energy is ≥60 dyn / cm, and especially when the surface energy is ≥70 dyn / cm, it is well wettable with water, making the wetting operation according to step d. of the aforementioned method particularly easy to adjust and adaptable to the corresponding conditions.

[0023] Particularly preferred is the determination of surface energy using test inks according to DIN ISO 8296, where the surface energy of the corresponding solid surface can be estimated in a rapid method. In this case, a commercially available test ink with a known surface energy or surface tension (surface energy and surface tension are equivalent for liquids) is applied to the solid surface, and the time it takes for the test ink to concentrate on the surface is observed. By testing several test inks in this way, test inks that no longer concentrate within the first few seconds after application are identified. With respect to these test inks with known surface energies, the surface energy of the solid surface is consistent with the surface energy of the test ink.

[0024] The adhesive film is, for example, a decoration, lettering, or one or more individual letters or decorative elements to be applied to the surface to be bonded. In particular, it can be a self-adhesive decorative paint film or a decorative film with an adhesive backing. Furthermore, the adhesive film can be a known drop protection film or other protective film.

[0025] In a preferred further embodiment of the invention, the adhesive film applicable in the method has at least one of the following features a to h:

[0026] a. The adhesive film includes a carrier film having the adhesive layer on one side and a paint layer on the other side.

[0027] b. The carrier membrane is a plastic membrane, a metal membrane, or a metal-plastic composite membrane.

[0028] c. The carrier membrane has a thickness in the range of 10 μm to 120 μm.

[0029] d. The adhesive layer has a thickness in the range of 10 μm to 80 μm, preferably 30 μm to 60 μm.

[0030] e. The adhesive layer has a uniform thickness.

[0031] f. The adhesive layer is composed of a homogeneous adhesive material.

[0032] g. The adhesive layer has a depth of 10cm. 2 up to 8m 2 The area within the specified range.

[0033] h. The paint layer has a thickness in the range of 20 μm to 150 μm, preferably 30 μm to 90 μm, and particularly preferably 40 μm to 60 μm.

[0034] Particularly preferably, at least features a., b., and g. above are implemented in combination with each other. In a further preferred embodiment, features a. to d. and g. and h., especially features a. to e. and g. and h., are implemented in combination with each other; in a particularly preferred embodiment, all features a. to h. are implemented in combination with each other.

[0035] Feature e. is particularly preferred in combination with feature f. Uniform thickness means that the adhesive layer is not locally weakened by microstructural channels or other microstructures used for air venting. The adhesive layer is preferably formed by applying a homogeneous adhesive material with a scraper, and accordingly has a generally flat and uniform surface. "Homogeneous" means that the adhesive material is free of particles, especially visible particles.

[0036] By using a microstructure-free adhesive layer, an adhesive film with an extremely thin carrier can be applied to the method of the present invention, and a high-gloss "Grade A surface" can still be obtained. Therefore, within the range of 10 μm to 120 μm given above, a carrier film with a thickness of 10 μm to 60 μm, preferably 10 μm to 50 μm, is further preferred, especially when the adhesive layer has no microstructure as described.

[0037] Particularly preferably, the adhesive layer may be composed of an acrylic adhesive having a layer thickness preferably in the range of 20 to 80 μm, particularly having a layer thickness of 50 μm.

[0038] With regard to physical surface activation, the method of the present invention preferably has at least one of the following additional features a to d:

[0039] a. The physical surface activation of the adhesive layer is performed by plasma treatment.

[0040] b. The physical surface activation of the adhesive layer is performed by corona treatment.

[0041] c. The physical surface activation of the adhesive layer is performed by flame treatment.

[0042] d. The physical surface activation of the adhesive layer is carried out in a vacuum.

[0043] Plasma treatment is particularly suitable for the method of the present invention because it enables the surface activation of the adhesive layer of the adhesive film in a particularly efficient and practically easy manner. Plasma refers to a cloud of gas comprising at least partially ionized gas, which enhances the surface energy for the activation of the adhesive layer surface. Suitable plasma generators are commercially available.

[0044] In principle, plasma treatment can be performed under atmospheric pressure or under overpressure (high-pressure plasma) or negative pressure (low-pressure plasma). For the purposes of the method of this invention, low-pressure plasma, particularly plasma treatment in a vacuum, is especially suitable. Vacuum preferably refers to a pressure <0.05 mbar, for example, about 0.02 mbar. Accordingly, it is particularly preferred that features a. and d. above be combined with each other. In this case, surface activation is performed, particularly within a processing chamber (plasma chamber) to be evacuated, where the adhesive film containing the adhesive layer to be activated is transferred. The processing time of the plasma treatment can, for example, be in the range of 10 s to 120 s.

[0045] In other cases, so-called cold plasma is preferred, in which atmospheric pressure conditions exist in principle, and in particular, no temperature rise occurs during the formation of the plasma.

[0046] As an alternative to plasma treatment, corona treatment is also suitable for physical surface activation. Corona treatment is based on a gas discharge method, which helps to increase the surface energy of the surface to be treated, thereby improving its wettability with water. Here, generally, an electrical discharge occurs between two electrodes at atmospheric pressure, where the generated electric field excites gas molecules, particularly those in the air, and, depending on the situation, causes them to break down. The resulting charged reactive particles react with the adhesive layer, leading to surface activation. Generally, compared to corona treatment, plasma treatment has the advantage that it can increase the surface energy to a greater extent, and the duration of surface activation is generally longer with plasma treatment than with corona treatment.

[0047] Furthermore, flame treatment is suitable for the physical surface activation of the adhesive layer. In flame treatment, the adhesive layer of the adhesive film is exposed to a flame consisting of an air / gas mixture, where a stable and oxidizing flame is generated. This also achieves a surface activation effect in the adhesive layer, thereby improving its wettable properties. Generally speaking, compared with flame treatment, corona treatment and especially plasma treatment have the advantage of typically achieving more uniform results over a surface area.

[0048] Particularly preferably, the apparatus for physical surface activation, especially the plasma treatment apparatus, can be part of an automated device for applying adhesive films.

[0049] In a particularly preferred embodiment of the method of the present invention, the method has the following additional feature a:

[0050] a. The adhesive layer is wetted by water atomization.

[0051] By atomizing the water, it is particularly advantageous to generate a defined amount of water in the form of fine droplets in the area of ​​the adhesive layer, wherein the droplets are deposited on the adhesive layer, and thus a water film is formed on the adhesive layer for further application of the adhesive film.

[0052] During water atomization, water is distributed in a very fine pattern in a gaseous environment, particularly in the air. Preferably, atomization achieves the distribution of very small water droplets in the air, which cause wetting of the gel layer. Preferably, during atomization, the water droplets in the air have an average diameter falling within the range of about 1 to 10 μm, particularly preferably between 2 and 5 μm, and even more preferably between 2 and 4 μm.

[0053] The water film formed by water droplets depositing on the adhesive layer is preferably very thin. Preferably, the droplets are distributed on the adhesive layer in a continuous film layer due to wetting, and this film layer has a thickness in the range of 1 nm to 1000 μm. Particularly preferably, the thickness of the water film is in the range of 10 nm to 500 μm, even more preferably in the range of 10 nm to 1000 nm, and most preferably 10 nm to 100 nm. The water film should, in particular, have a certain thickness to compensate for non-uniformity in the adhesive layer.

[0054] Particularly preferably, the atomization can be induced using an ultrasonic atomizer, wherein the water is vibrated under the action of ultrasound. This causes droplet separation. The size of the droplets can be affected by adjusting the frequency of the ultrasound. The higher the frequency of the ultrasound, the finer the droplets produced. In this regard, ultrasonic atomizers are particularly suitable for wetting the adhesive layer. The wetting or atomization can be adjusted in a manner such that the water film formed on the adhesive layer is sufficient to compensate for non-uniformity in the adhesive layer. Preferably, the formation of large droplets should be avoided, which can also be adjusted, particularly by the duration of wetting.

[0055] Furthermore, common spray guns are suitable for wetting the surface-activated adhesive layer. For example, the spray gun can be operated via a lifting cylinder. By adjusting the cylinder stroke speed and / or the extension stroke or cylinder stroke, the wetting intensity can be changed, thereby achieving a uniformly wetted adhesive layer.

[0056] Furthermore, wetting can be performed using a stage containing a movable XY head, which carries a wetting unit such as a spray gun. The XY head can be used in a manner similar to that of a 3D printer, allowing it to completely pass over the surface to be wetted.

[0057] Particularly preferably, the means for wetting the adhesive layer of the adhesive film, such as an ultrasonic atomizer or a spray gun, may be part of an automated device for applying the adhesive film.

[0058] In a preferred embodiment of the method of the present invention, the method has the following additional feature a:

[0059] a. The adhesive film is initially pressed into the surface to be bonded in a dotted manner, so that the adhesive film comes into contact with the surface to be bonded.

[0060] By initially applying the adhesive film in dots to the surface to be bonded, the contact area can then extend radially outward until the adhesive layer fully contacts the surface, thus achieving a highly reliable, uniform, and bubble-free bond. This initial dot application of the adhesive film can be performed using at least one stamping device, which presses the adhesive film into dots onto the surface to be bonded. Particularly preferably, the stamping device can be a component of an automated device for applying the adhesive film. Such a stamping device may, for example, include a cylinder, an extendable piston, and a punch, particularly a rounded punch.

[0061] In the process of providing an adhesive film containing an adhesive layer, the protective film of the protective adhesive layer can be removed first, and then the adhesive film can be hung or stretched in a device for further carrying out the method. For this purpose, for example, a carrier film can be provided on which the adhesive film is mounted. Accordingly, the carrier film can be part of a device for applying the surface-activated and wetted adhesive film to the component to be bonded or its surface. Here, the adhesive film can be attached to the carrier film with the side facing away from the adhesive layer, such that the side of the adhesive film containing the adhesive layer is exposed and can contact the surface of the component.

[0062] In a particularly preferred embodiment of the method, the method has the following additional feature a.

[0063] a. Using an elastic diaphragm to bring the adhesive film into contact with the surface to be bonded, the diaphragm being offset to press the adhesive film firmly onto the surface to be bonded.

[0064] Using an elastic diaphragm to press the adhesive film onto the surface to be bonded is a particularly preferred approach for the method of the present invention, because it enables a particularly uniform bonding process on the one hand, and particularly advantageously allows for the automation of the process on the other. For the purpose of allowing for offset, it is preferable to suspend the elastic diaphragm along its edge, for example, in a suitable frame.

[0065] Particularly preferably, regarding the offset of the elastic diaphragm, the method of the present invention has the following additional feature a:

[0066] a. The elastic diaphragm is deflected by generating negative pressure, particularly a vacuum, in the space between the elastic diaphragm and the surface of the component.

[0067] In this embodiment of the method, an adhesive film, for example, attached or otherwise suspended on the carrier film, is located between the elastic diaphragm and the surface of the component. By generating a negative pressure in the space between the elastic diaphragm and the component surface, the elastic diaphragm is pulled toward the component, thereby bringing the adhesive film into contact with the component surface. Here, negative pressure refers to a pressure below atmospheric pressure (atmospheric pressure ≈ 1 bar). Preferably, the negative pressure falls within the range of 0.01 mbar to 1 bar, particularly preferably between 0.01 mbar and 750 mbar. Particularly preferably, the pressure is below 0.05 mbar. The pressure may, for example, be about 0.02 mbar.

[0068] The offset of the diaphragm initially creates point-like contact areas on the surface of the component due to the arching of the diaphragm. In the subsequent process, other areas of the diaphragm are also increasingly pulled towards the surface, causing the contact areas to expand radially outward until the adhesive layer is in full contact with the surface.

[0069] This is nearly impossible with traditional manual application. To ensure proper positioning of the adhesive film on the surface during manual application, it is usually necessary to manually align the edges of the adhesive film first and then press it down.

[0070] In particular, further displacement of the diaphragm can be achieved by increasing the pressure on the side of the elastic diaphragm facing away from the component. Generally, diaphragm displacement can be achieved by generating a pressure difference. Specifically, the pressure in the space between the elastic diaphragm and the component surface is lower than the pressure on the other side of the diaphragm.

[0071] The pressure difference can be achieved, for example, by creating a vacuum between the elastic diaphragm and the component surface, and by having atmospheric pressure present or generated on the other side of the diaphragm. In other technical solutions, atmospheric pressure can exist between the elastic diaphragm and the component surface. In these cases, to generate the pressure difference, overpressure (overpressure – pressure higher than atmospheric pressure) is generated on the other side of the diaphragm, causing the elastic diaphragm to shift towards the component. This also causes the adhesive film disposed between the elastic diaphragm and the component surface, with the surface-activated and wetted adhesive layer leading, to be pressed against the surface of the component.

[0072] To adjust the pressure difference, for example, a vacuum can be first applied to the negative pressure chamber located in the space between the elastic diaphragm and the surface of the component, and to the pressure compensation chamber located on the side of the diaphragm opposite to the negative pressure chamber. The pressure compensation chamber is then ventilated, thereby restoring atmospheric pressure on this side, which causes the elastic diaphragm to shift toward the component.

[0073] A particular advantage of the method of the present invention is that it can be automated. Therefore, it is particularly preferred to implement the method using an automated system. Especially in this embodiment, the method can be advantageously applied, for example, to motor vehicle production. In this case, the component to be bonded is preferably a motor vehicle body, or a part of a motor vehicle body, or an accessory of a motor vehicle. In this embodiment, the method preferably includes two or more, particularly all, of the steps a. to d. that follow immediately below.

[0074] a. To apply at least one paint to the body of a motor vehicle or a component thereof.

[0075] b. Dry and / or cure the at least one paint.

[0076] c. As appropriate, install the accessory onto a load-bearing component of a motor vehicle body coated with at least one of the said dried and / or cured paints.

[0077] d. Applying the adhesive film, including the adhesive layer, to the surface of the motor vehicle body coated with at least one dried and / or cured paint, or to a component of the motor vehicle body, or to one of the accessories mounted on the motor vehicle body.

[0078] Preferably, the adhesive film is applied in the manner described above according to the aforementioned feature d.

[0079] The at least one paint is preferably a common multi-layer automotive paint. Typically, the car body and body parts are primed, a primer is applied, and a clear coat is applied last. The necessary steps and intermediate steps for this are known. For the purposes of this invention, the important point is that the at least one paint on the substrate to be bonded is preferably dried and cured, i.e., it provides a generally pressure-resistant surface and no longer contains solvents. After applying the adhesive film according to the invention, a clear coat is generally unnecessary or unnecessary.

[0080] In the context of this invention, the concept of "accessory" covers a broad range. On one hand, it includes unpainted components, such as vehicle windows or headlights, but on the other hand, it also includes painted components, such as hoods, doors, fenders, roof elements, or colored plastic parts. Depending on the circumstances, paint is applied to these accessories in a manner independent of the vehicle body, and then dried and / or cured.

[0081] The present invention also includes an apparatus for applying an adhesive film to the surface of a component. This apparatus is specifically configured to carry out the method described above. The apparatus of the present invention has the following features a. to d.:

[0082] a. The device includes means for accommodating an adhesive film containing an adhesive layer.

[0083] b. The device includes means for physically surface-activating the adhesive layer of the adhesive film.

[0084] c. The apparatus includes means for wetting the adhesive layer of the adhesive film.

[0085] d. The device includes means for bringing the surface-activated and wetted adhesive film into contact with the surface of the component to be bonded.

[0086] For further details regarding the device, please refer to the description above in conjunction with the method of the present invention.

[0087] The device for accommodating the adhesive film containing the adhesive layer can in particular be a carrier film for positioning the adhesive film in the area of ​​the surface of the component to be bonded. Preferably, the adhesive film is attached to the carrier film with its side facing away from the adhesive layer. Preferably, the carrier film can be fixed in or on a frame. For this purpose, the carrier film can have positioning and fixing devices that simplify fixing on the frame.

[0088] Preferably, the adhesive film is arranged on the carrier film in such a manner that the carrier film containing the adhesive film is located between the means (particularly an elastic diaphragm) for pressing the adhesive film onto the component and the surface of the component to be bonded. Since it is typically necessary to press the adhesive film, including its edges, onto the surface to be bonded, the carrier film simplifies the positioning of the adhesive film. After the adhesive film is pressed, it is preferable to peel the carrier film off from the adhesive film.

[0089] As an alternative to the carrier film, other devices for accommodating the adhesive film may also be provided, such as hooks or similar mechanical fastening devices for hooking the adhesive film.

[0090] With regard to the apparatus for physical surface activation of the adhesive layer, the device of the present invention preferably has at least one of the following additional features a to d:

[0091] a. The apparatus for surface activation of the adhesive layer includes an apparatus for generating plasma.

[0092] b. The apparatus for surface activation of the adhesive layer includes an apparatus for corona treatment.

[0093] c. The apparatus for surface activation of the adhesive layer includes apparatus for flame treatment.

[0094] d. The apparatus for surface activation of the adhesive layer includes a device for generating a vacuum.

[0095] The apparatus for generating plasma, or the apparatus for corona treatment, or the apparatus for flame treatment, can be any apparatus known to those skilled in the art and applicable to surface activation. With regard to the apparatus for generating plasma, a low-pressure plasma apparatus is particularly preferred. To generate low pressure, and particularly a vacuum, a vacuum pumping device is particularly preferred, into which the adhesive layer of the adhesive film is fed, thereby enabling plasma treatment in a vacuum.

[0096] With regard to the apparatus for wetting the adhesive layer of the adhesive film, the device of the present invention preferably has the following additional features:

[0097] a. The apparatus for wetting the adhesive layer includes an atomizing device, particularly a water atomizer.

[0098] The atomizing device is, for example, an ultrasonic atomizer, which can adjust and regulate the droplet size in the generated mist in a particularly suitable manner. Alternatively, a spray gun can be used for this purpose.

[0099] With regard to the apparatus for bringing the adhesive film into contact with the surface to be bonded, the device of the present invention preferably has at least one of the following additional features a. and b.:

[0100] a. The device for bringing the adhesive film into contact with the surface to be bonded includes a reversible elastic diaphragm for pressing the adhesive film against the surface of the component to be bonded.

[0101] b. The device for bringing the adhesive film into contact with the surface to be bonded includes at least one stamping device for making point contact between the adhesive film and the surface to be bonded.

[0102] Preferably, the stamping device may consist of, in particular, a rounded punch, an extendable piston, and an operable cylinder. For further details regarding the at least one stamping device, please also refer to the description above.

[0103] With regard to the elastic diaphragm, the device may in particular have at least one of the following additional features a to c:

[0104] a. The elastic diaphragm is made of an elastic polymer material, particularly of natural rubber or silicone.

[0105] b. The elastic diaphragm has a uniform thickness.

[0106] c. The elastic diaphragm has weakening and / or reinforcing regions for specifically influencing the geometry of the arched state.

[0107] Particularly preferably, features a. and b. above, or features a. and c. above, are combined to achieve the desired effect.

[0108] In the process of forming the aforementioned point-like contact areas, the geometry that influences the arching state of the diaphragm may be helpful. For example, if there is a recess in the surface to be bonded, ideally the point-like contact area should be formed at the lowest point of that recess. It is preferable to avoid forming circular contact areas, which could otherwise generate air bubbles.

[0109] If one area of ​​an elastic diaphragm is thinner than the others, it will be more prone to arching and buckling under pressure or negative pressure compared to the rest of the diaphragm. The opposite occurs when the elastic diaphragm is reinforced.

[0110] Furthermore, introducing weakening and / or reinforcing regions into the elastic diaphragm helps to influence the expansion of the contact area. This is particularly helpful in bonding adhesive films to curved surfaces, especially to surfaces with concave areas.

[0111] Preferably, the device can be constructed in such a way that the elastic diaphragm can be deflected by a pressure difference, thereby pressing the adhesive film onto the surface of the component to be bonded.

[0112] Preferably, the device of the present invention has the following additional feature a:

[0113] a. The device for bringing the adhesive film into contact with the surface to be bonded includes a device for generating a negative pressure in the space between the elastic diaphragm and the surface of the component to deflect the elastic diaphragm.

[0114] In a further embodiment of this aspect of the device of the invention, the means for bringing the adhesive film into contact with the surface to be bonded further includes a means for increasing the pressure on the other side of the elastic diaphragm compared to the negative pressure generated in the space between the elastic diaphragm and the surface of the component. This means for increasing the pressure on the other side of the elastic diaphragm can be, for example, an exhaust valve located in a pressure compensation chamber. In this embodiment, a negative pressure chamber can be provided in the space between the elastic diaphragm and the surface of the component, and a pressure compensation chamber can be provided on the other side of the diaphragm. To deflect the elastic diaphragm, a negative pressure can first be applied to both the negative pressure chamber and the pressure compensation chamber, particularly by evacuating both chambers to create a vacuum. In this state, the elastic diaphragm has not yet deflected because the pressure on both sides of the diaphragm is the same (vacuum). After a vacuum is achieved, the pressure in the pressure compensation chamber is compensated relative to the surrounding atmospheric pressure by manipulating the exhaust valve, so that the pressure in the pressure compensation chamber is increased compared to the negative pressure chamber. The elastic diaphragm is offset toward the component due to this measure, thereby pressing the adhesive film disposed between the diaphragm and the component toward the surface of the component to be bonded in such a manner that the surface-activated and wetted adhesive layer is in front.

[0115] The components to be bonded can be, in particular, painted body parts of motor vehicles, or other painted components or workpieces. The components may also have a clear coat already applied. In principle, various types of components are suitable as substrates for the adhesive film to be applied. By optimizing the application process of the adhesive film onto a surface according to the invention, even components that are difficult to handle in conventional ways can be bonded accordingly.

[0116] In a particularly preferred embodiment, the device of the present invention has the following additional feature a:

[0117] a. The device includes a frame configured to form a negative pressure chamber together with the surface to be bonded and an elastic diaphragm, the adhesive film being disposed in the negative pressure chamber, and the elastic diaphragm being able to arch into the negative pressure chamber when a negative pressure is applied to the negative pressure chamber.

[0118] As previously mentioned, particularly preferably, during the application of the adhesive film, negative pressure is applied in the region between the surface to be bonded and the elastic diaphragm. The frame is provided for this purpose.

[0119] For temperature regulation, the elastic diaphragm can be constructed with a double wall and has a connector for temperature-regulating media such as water.

[0120] The device for securing the adhesive film or carrier film may be, for example, a pin or hook that corresponds to a hole in the adhesive film or carrier film.

[0121] In a preferred further embodiment of the invention, the device has at least one of the following features a to f:

[0122] a. The frame is rectangular.

[0123] b. The frame has a first opening that is closed by the diaphragm.

[0124] c. The frame includes at least one resilient sealing element that is capable of sealingly abutting the surface.

[0125] d. The frame includes a second opening, and the at least one resilient sealing element is fixed to the edge of the second opening.

[0126] e. The frame includes at least one connector for a negative pressure source used to apply negative pressure to the negative pressure chamber.

[0127] f. The frame includes at least one support as a means for securing the adhesive film.

[0128] Preferably, at least features a. to e. above are implemented in combination with each other; particularly preferably, all features a. to f. are implemented in combination with each other.

[0129] The at least one sealing element is used to seal the negative pressure chamber. It is preferably made of an elastic polymer material, such as the aforementioned natural rubber. The at least one connector for the negative pressure source is used to generate negative pressure in the negative pressure chamber.

[0130] In another preferred embodiment of the invention, the device has at least one of the following features a to d:

[0131] a. The framework consists of two or more sub-frames.

[0132] b. The frame is rectangular and consists of two or more rectangular sub-frames.

[0133] c. The frame includes a first rectangular subframe, which includes the at least one connector for the negative pressure source and the at least one resilient sealing element is fixed to the subframe.

[0134] d. The frame includes a second rectangular subframe that includes the at least one support for the adhesive film.

[0135] Preferably, at least features a. to c. above are implemented in combination with each other; particularly preferably, all features a. to d. are implemented in combination with each other.

[0136] When using two or more subframes, it may be necessary to install more sealing elements at the joint surfaces of the subframes to ensure the airtightness of the negative pressure chamber.

[0137] In order to control or regulate negative pressure as described above, the device may have a suitable control or regulation device.

[0138] In another preferred embodiment of the invention, the device has at least one of the following features a. to c., preferably a combination of features a. and b. or a. and c.:

[0139] a. The device includes a pressure compensation chamber, which is primarily defined by the diaphragm.

[0140] b. The device includes at least one connector for a pressure source or negative pressure source, which is introduced into the pressure compensation chamber.

[0141] c. The device includes at least one valve for ventilating the pressure compensation chamber.

[0142] Depending on the situation, this pressure compensation chamber may be used to generate or enhance the arching of the elastic diaphragm. When a negative pressure is applied in the negative pressure chamber, ventilating the pressure compensation chamber through the valve is sufficient to induce or enhance the desired arching of the diaphragm.

[0143] Particularly preferably, the equipment is integrated into an automated system, such as a robot. The automated system is preferably a production line for manufacturing motor vehicles.

[0144] In principle, the method and equipment described are certainly not limited to applications in the production of motor vehicles. For example, the adhesive film can also be applied to other mass-produced products (e.g., bicycles) according to the present invention.

[0145] Further features and advantages of the present invention are described below in conjunction with the accompanying drawings, which illustrate embodiments of the apparatus or components thereof for applying an adhesive film to a component. The illustrated and described embodiments are for illustrative purposes only and do not constitute any limitation thereof. Attached Figure Description

[0146] in:

[0147] Figure 1 This is a schematic cross-sectional view of a component of the apparatus of the present invention for applying an adhesive film to the surface of a component;

[0148] Figure 2 This is a schematic cross-sectional view of another preferred embodiment of a component of the apparatus of the present invention for applying an adhesive film to the surface of a component;

[0149] Figure 3 This is a schematic cross-sectional view of another preferred embodiment of a component of the apparatus of the present invention for applying an adhesive film to the surface of a component;

[0150] Figure 4 A cross-sectional view of a processing cover, which is a component of the apparatus of the present invention for applying adhesive film to the surface of a component; and

[0151] Figure 5 For example, located on the robotic arm Figure 4 The side view of the processing cover shown. Detailed Implementation

[0152] Figure 1 This is a schematic cross-sectional view of a component of an apparatus 100 for applying an adhesive film 10 to the surface 20 of a component. The adhesive film 10 has an adhesive layer 11 disposed on the side opposite to the component. According to the method of the invention, the adhesive layer 11 is physically surface-activated and then wetted with water vapor, thereby forming a water film 12 on the adhesive layer 11.

[0153] The apparatus for physical surface activation in device 100, which is not shown in detail here, is preferably a plasma treatment apparatus. Plasma treatment is preferably performed in a vacuum, therefore a vacuum pumping device is also provided. Alternatively, a corona treatment apparatus or a flame treatment apparatus may be provided.

[0154] In order to generate the water film 12, the device 100 includes an atomizing device not shown in detail herein, preferably an ultrasonic atomizer, a spray gun, or a similar spray unit.

[0155] To press the adhesive film 10, which has been surface-activated and wetted on the adhesive side, a displaceable elastic diaphragm 101 is provided. An overpressure chamber 102 is provided on the side of the elastic diaphragm 101 facing away from the adhesive film 10. Overpressure (overpressure: >1 bar) is generated in the overpressure chamber 102 by means of a device (not shown in detail here) for generating overpressure. This overpressure causes the elastic diaphragm 101 to shift toward the surface 20 of the component, specifically by arching the elastic diaphragm 101 forward in a convex shape. In the further forward arching of the elastic diaphragm 101 toward the surface 20 of the component (not shown in detail here), the adhesive film 10 located between the diaphragm and the component surface is pressed increasingly toward the surface 20 of the component, thereby causing the adhesive film 10 to adhere to the surface 20 of the component by means of the surface-activated and wetted adhesive layer 11.

[0156] To perform surface activation and wetting of the adhesive layer 11 of the adhesive film 10, the adhesive film 10 can first be placed in a processing chamber (not shown in detail in this drawing), wherein the adhesive layer 11 of the adhesive film 10 is aligned with the open side of the processing chamber. A carrier film can be provided for placing the adhesive film 10 in the processing chamber, on which the adhesive film is attached with its side facing away from the adhesive layer. Here, the adhesive film 10 is first placed on the carrier film, and then the carrier film is inserted into the processing chamber. The processing chamber containing the adhesive film 10 is positioned on a plasma generating unit, which in particular includes corresponding plates with electrodes. A vacuum is drawn in the currently closed space of the processing chamber to create a vacuum inside the processing chamber, thereby enabling plasma treatment of the adhesive layer 11 according to the present invention. The processing chamber, containing the adhesive film with the surface-activated adhesive layer inside, can then be positioned at a wetting station (not shown), where the surface-activated adhesive layer 11 is wetted by means of an atomizing device, in particular by means of an ultrasonic atomizer.

[0157] The processing cover, which contains an adhesive film 10 with a surface-activated and wetted adhesive layer 11, can then be positioned on the component to be bonded, such as on a vehicle body. The adhesive film 10 is then pressed firmly onto the surface 20 of the component to be bonded, particularly by means of the elastic diaphragm 101, wherein the adhesive film 10 separates from a carrier film, which may be provided as appropriate. The processing cover can then be positioned in an ejection station for removing the carrier film. After the carrier film is removed, the processing cover is ready for a new round of operations.

[0158] Figure 2 Another preferred embodiment of a device 200 for applying an adhesive film 10, comprising an adhesive layer 11, to a surface 20 of a component is shown. Here, the adhesive film 10 is also pressed onto the surface 20 of the component by means of a repositionable elastic diaphragm 101. (The last sentence appears to be incomplete and possibly refers to a different device.) Figure 1 The difference in the technical solutions shown is that, just like Figure 2 In the illustrated device 200, a space 103 configured as a negative pressure chamber is provided between the offset elastic diaphragm 101 and the surface 20 of the component. The pressure sealing of the negative pressure chamber 103 is ensured by a seal 105, wherein the seal 105 isolates the boundary of the negative pressure chamber 103 from the surface 20 of the component.

[0159] To press the adhesive film 10 onto the surface 20 of the component, a negative pressure is applied in the negative pressure chamber 103, preferably by evacuation using a device not shown in detail herein. Atmospheric pressure remains in the space 104 located on the other side of the diaphragm 101, thus causing the elastic diaphragm 101 to shift toward the surface 20 of the component due to the pressure difference between the space 104 and the negative pressure chamber 103. This shift of the diaphragm 101 presses the adhesive film 10 against the surface 20 of the component with the surface-activated and wetted adhesive layer 11 on it preceding it.

[0160] Figure 3 This is a schematic cross-sectional view of a component of a device 300 of the present invention for applying an adhesive film 10 comprising an adhesive layer 11 to a surface 20 of a component. (The same applies to...) Figure 1 and Figure 2 Similar to the embodiment shown, the adhesive layer 11 of the adhesive film 10 is also physically surface-activated and wetted to form a water film 12 on the adhesive layer 11 of the adhesive film 10. The embodiment of the device 300 generally corresponds to... Figure 1 In the illustrated embodiment 100, a repositionable diaphragm 101 is provided, which can be shifted toward the surface 20 of the component by means of overpressure in the overpressure chamber 102, thereby pressing the adhesive film 10 onto the surface 20 of the component with the adhesive layer 11 in front. Furthermore, this embodiment includes a stamping device comprising a operable cylinder 31, an extendable piston 32, and a punch 33. With this stamping device, the adhesive film 10 can be pressed point-by-point onto the surface 20 of the component by means of the diaphragm 101 located between the stamping device and the adhesive film. This specifically causes the surface-activated and wetted adhesive layer 11 of the adhesive film 10 to adhere to the surface 20 of the component in a manner that extends radially outward uniformly from a central starting point. This contributes to a particularly uniform and reliable application of the adhesive film 10.

[0161] Similarly, these stamping devices 31, 32, and 33 can also be applied to equipment that uses negative pressure to apply adhesive film 10 onto the surface 20 of a component, for example... Figure 2 The device 200 is shown. In this type of technical solution for applying adhesive film 10, especially when the component is particularly sensitive to pressure, the component may deform due to the applied negative pressure, particularly arching forward toward the device 200. This forward arching can be suppressed by correspondingly extended stamping devices 31, 32, 33, which are also used to stabilize pressure-sensitive components and, depending on the situation, particularly flexible components.

[0162] Particularly preferably, the feeding and pressure differential adjustment of the stamping devices 31, 32, and 33 are performed in parallel over time, especially the adjustment of the negative pressure. It is preferable to take into account the fact that the pressure-sensitive component may deform at the same time as the vacuuming operation begins. Therefore, it is preferable to extend the stamping devices 31, 32, and 33 until they come into contact with the component at the same time as the vacuuming operation begins.

[0163] Preferably, the punch 33 is fed in a manner coordinated with the negative pressure regulation. In other words, it is preferable that the differential pressure regulation causing the elastic diaphragm 101 to deviate is matched with the feed of the punching devices 31, 32, and 33. In particular, the coordination between the feed of the punch 33 and the negative pressure regulation is achieved by adjusting over time or according to the actual negative pressure. Particularly preferably, the punching devices 31, 32, and 33 are fed in an open-loop or closed-loop manner. In particular, the operation of the punching devices is designed to compensate for the force acting on the component during the application of the adhesive film 10 due to the differential pressure, i.e., to generate force compensation.

[0164] The extension of the stamping devices 31, 32, and 33 can be time-dependent. For example, the stamping devices 31, 32, and 33 can be extended a few seconds after the start of vacuuming, or after a settable time interval, such as 2, 3, 4, or 5 seconds.

[0165] In other technical solutions, the stamping devices 31, 32, and 33 can be extended based on the measured actual pressure acting on the diaphragm 101, particularly when the pressure falls below a set pressure threshold during negative pressure adjustment. In this embodiment, one or more pressure sensors are preferably used. This allows the stamping devices 31, 32, and 33 to be extended, for example, when a pressure of 100 mbar or another pressure threshold is reached. In particular, this adjustment can be matched to the characteristics of the component to be bonded, and adjusted specifically according to the pressure-sensitive characteristics of the corresponding component.

[0166] Figure 4 To process the side view of the cover 200, its basic structure corresponds to, as follows: Figure 2 The device 200 is shown. Therefore, corresponding components are indicated by the same reference numerals. The adhesive film 10 can be applied, for example, to the painted surface 20 of a motor vehicle by means of the processing cover 200.

[0167] The processing cover 200 includes a rectangular frame, which is composed of rectangular sub-frames 130 and 140. Sub-frames 130 and 140 are hermetically connected by a seal 142. In sub-frame 130, a carrier membrane 150 is fixed, for example, by means of several pins. For this purpose, the carrier membrane 150 may have several corresponding holes into which the pins can be inserted.

[0168] For example, an elastic diaphragm 101 made of natural rubber is arranged parallel to the carrier membrane 150. The diaphragm is airtightly tensioned between the base plate 110 and the sub-frame 130 of the processing shroud 200. The diaphragm closes an opening in the frame defined by the sub-frame 130. For this purpose, for example, several screws are screwed through the sub-frame 130 into the base plate 110. The base plate 110 and the elastic diaphragm 101 surround a pressure compensation chamber 104. Air can enter the pressure compensation chamber 104 through a valve 114.

[0169] The frame, consisting of sub-frames 130 and 140, is constructed to form a negative pressure chamber 103 together with the bonding surface 20 of component 170 and the elastic diaphragm 101. A carrier membrane 150 containing the adhesive membrane 10 is disposed within this negative pressure chamber, and the elastic diaphragm 101 can arch into the negative pressure chamber when a negative pressure is applied. For this purpose, the geometry of the sub-frame 140 matches that of the surface 20, thereby achieving a form-fitting contact between the surface 20 and the sub-frame 140 of the processing shroud 200. An elastic sealing element 105 is fixed at the edge of the frame at the opening defined by the sub-frame 140. The frame is sealed to the surface 20 through this sealing element. The negative pressure chamber 103 can be evacuated via a connector 148 coupled to a negative pressure source and a channel 146 passing through the sub-frame 140. In the state shown here, the elastic diaphragm 101 does not arch, indicating that the pressure in the pressure compensation chamber 104 is the same as the pressure in the negative pressure chamber 103.

[0170] To deflect the elastic diaphragm 101, a pressure difference is created between the negative pressure chamber 103 and the pressure compensation chamber 104, with a higher pressure achieved in the pressure compensation chamber 104. This can be achieved specifically by first evacuating both the negative pressure chamber 103 and the pressure compensation chamber 104. Then, the pressure compensation chamber 104 is ventilated via valve 114, causing the pressure in the pressure compensation chamber 104 to return to near atmospheric pressure. This causes the elastic diaphragm 101 to arch towards the surface 20 of the component 170, thereby pressing the surface-activated and wetted adhesive film 10 according to the invention onto the surface 20 of the component.

[0171] After the adhesive membrane 10 is pressed firmly onto the surface 20 of the component 170, the negative pressure chamber 103 and the pressure compensation chamber 104 can be adequately ventilated. The elastic diaphragm 101 can then return to its initial state. Typically, the carrier membrane 150 is peeled off from the adhesive membrane 10, leaving the adhesive membrane 10 on the surface 20.

[0172] Figure 5An embodiment of the device of the present invention is shown, wherein the processing shroud 200 is coupled to a robotic arm 430, or generally referred to as a lifting device, of an automation system 400 via a lower structure 180 located on one side of a base plate 110 of the processing shroud 200. The automation system 400 has a base 410 including a pivotable upper component 420. The upper component 420 is rotatable about a rotation axis 2. The robotic arm 430 is pivotable about a pivot axis 4. This enables height adjustment of the processing shroud 200.

[0173] A thrust cylinder 440 is provided between the robotic arm 430 and the handling cover 200. The thrust cylinder 440 is linearly expandable along the displacement direction 8. Furthermore, the thrust cylinder 440 is rotatable about the rotation axis 6. This allows for precise distance and alignment between the handling cover 200 and the surface 20 of the component.

[0174] The automated system 400 enables the processing shroud 200, containing the adhesive film 10, to pass through various stations, thereby implementing the described steps for surface activation and wetting of the adhesive layer 11 of the adhesive film 10. For details regarding the various stations of the processing shroud, particularly the vacuuming device, plasma treatment device, and wetting device, please also refer to [the relevant documentation / reference needed]. Figure 1 The description.

Claims

1. A method for applying an adhesive film (10) to the surface (20) of a component, comprising the following steps: a. Provide an adhesive film (10) containing an adhesive layer (11); b. Provide a component containing the surface (20) to be bonded; c. Perform physical surface activation of the adhesive layer (11) of the adhesive film (10); d. Wet the adhesive layer (11) of the adhesive film (10); and e. To bring the surface-activated and wetted adhesive film (10) into contact with the surface (20) of the component to be bonded; The physical surface activation includes plasma treatment and / or flame treatment.

2. The method according to claim 1, further comprising: a. The adhesive layer (11) is wetted by water atomization.

3. The method according to any one of the preceding claims further comprises: a. The adhesive film (10) is initially pressed in a dotted manner onto the surface to be bonded, so that the adhesive film (10) comes into contact with the surface (20) to be bonded.

4. The method according to any one of the preceding claims further comprises: a. Using an elastic diaphragm (101) to bring the adhesive film (10) into contact with the surface (20) to be bonded, the diaphragm being offset to press the adhesive film onto the surface to be bonded.

5. The method of claim 4, further comprising: a. The diaphragm (101) is deflected by generating negative pressure in the space (103) between the elastic diaphragm (101) and the surface (20) of the member.

6. The method according to claim 5, wherein the negative pressure is a vacuum.

7. An apparatus (100; 200; 300) for applying an adhesive film (10) to a surface (20) of a component, comprising: a. A device for accommodating an adhesive film (10) containing an adhesive layer (11); b. An apparatus for physically surface-activating the adhesive layer (11) of the adhesive film (10); c. A device for wetting the adhesive layer (11) of the adhesive film (10); d. A device for bringing the surface-activated and wetted adhesive film (10) into contact with the surface (20) of the component to be bonded; The apparatus for physically surface-activating the adhesive layer (11) includes apparatus for generating plasma and / or apparatus for flame treatment.

8. The apparatus of claim 7, wherein the apparatus is used to implement the method of any one of claims 1 to 6.

9. The device according to claim 7, further comprising the following additional features: a. The device for wetting the adhesive layer (11) includes an atomizing device.

10. The device according to claim 9, wherein the means for wetting the adhesive layer (11) comprises a water atomizer.

11. The device according to any one of claims 7 to 10, comprising at least one of the following additional features: a. The device for bringing the adhesive film (10) into contact with the surface to be bonded (20) includes a reversible elastic diaphragm (101) for pressing the adhesive film against the surface to be bonded of the component. b. The device for bringing the adhesive film (10) into contact with the surface to be bonded (20) includes at least one stamping device (31, 32, 33) for making point contact between the adhesive film and the surface to be bonded.

12. The device according to claim 11, further comprising the following additional features: a. The means for bringing the adhesive film (10) into contact with the surface (20) to be bonded includes means for generating a negative pressure in the space (103) between the elastic diaphragm (101) and the surface (20) of the member to deflect the elastic diaphragm.

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