Method and device for removing a film-type plastic coating from a carrier substrate

Abstract

The invention relates to a method for removing a film-type plastic coating provided on a surface of a panel-type carrier substrate, wherein, by means of a positioning device, a cover surface or a casing surface of a rotatable roller is brought into physical contact with the plastic film as a contact surface, wherein the contact surface is also applied with a contact force which has a component directed perpendicular to the surface of the carrier substrate from which the coating is to be removed, and the contact surface and the carrier substrate are moved relative to one another in a first section of the carrier substrate, without releasing the physical contact, wherein the plastic film is removed at least in the first section, wherein the movement of the contact surface occurs via a rotation of the roller.

Description

[0001] Method and device for removing a film-like plastic coating from a carrier substrate

[0002] The invention generally relates to a method for stripping plate-shaped carrier substrates. It particularly relates to the removal of a film-like plastic coating present on the surface of such a carrier substrate. The invention also relates to an apparatus for carrying out the method.

[0003] Approximately 85% of all manufactured photovoltaic modules consist of a composite of the following materials: glass plate / plastic film / several adjacent silicon wafers / one or more plastic films. Here, the glass plate forms a plate-shaped carrier substrate. The coating, which is removed from the glass plate, for example, during the recycling of photovoltaic modules, but also in other processes, such as those used in the production or processing of photovoltaic modules, consists of at least one polymer layer, with the glass plate and coating sharing a common surface. The common surface refers to those surfaces of the glass plate and its coating that directly border one another.

[0004] As is well known, the individual layers of photovoltaic modules must be bonded together in such a way that they remain functional for 20 years or more, due to the desired long service life and harsh application conditions such as temperature, temperature fluctuations, radiation exposure, humidity, and others. Consequently, the stripping of the glass panels used as cover panes for photovoltaic modules poses significantly higher requirements than, for example, the removal of replaceable solar control films on window panes or similar delaminations.The method according to the invention for removing a film-like plastic coating from the carrier substrate of such a durable and strong composite material subjected to a wide variety of stresses will be explained using the example of photovoltaic modules, but can also be applied to other composite materials in which film-like plastic coatings are applied to plate-shaped substrates.

[0005] A plate-shaped carrier substrate, comparable to a glass plate, refers to flat material layers that extend in a plane and whose thickness, measured perpendicular to this plane and between the two surfaces of the carrier substrate, is many times smaller than the dimensions of the surfaces. Such a carrier substrate can optionally be transparent. The plate-shaped carrier substrate is also referred to below as the carrier substrate.

[0006] A film-like plastic coating is considered here to be a coating formed by an adhesion or adhesive film. A film is generally defined as a structurally and materially homogeneous sheet-like structure which serves to cover (packaging, decorative layer, wear layer, protective layer, etc.) a material, to separate or to join two materials. It is irrelevant whether the homogeneity of the sheet-like structure already existed during manufacture or the application of the coating or only arose during manufacture or use. The film-like plastic coating is also referred to below as a plastic film for short. In the case of photovoltaic modules, the film consists of a plastic and is designed as a coating on the carrier substrate for the purpose of bonding it to the silicon wafers or to protect the silicon wafers.

[0007] A first step in the separation of composite materials is described in the international patent application with application number PCT / DE2022 / 200078 "Method for separating valuable materials in a composite component." The process described therein is incorporated by reference in its entirety.

[0008] The "Method for separating valuable materials in a composite component" described in the application PCT / DE2022 / 200078 first separates the energy-absorbing layer of the semiconductor material, for example the silicon wafer 04, from an adjacent plastic film 03 and / or an adjacent plastic film composite 05. To extract the semiconductor material from the composite component, at least one predetermined breaking point (08) is introduced into the plastic film 05 such that the plastic film 05 breaks at the predetermined breaking point (08) under the pressure of the gas generated as a result of heating of the semiconductor material, so that open pockets are created in the plastic film 05 and the silicon wafers can be removed from the open pockets. This state is shown in Fig. 1. The previous position of the silicon wafers 04 is shown in dashed lines.

[0009] After carrying out this process according to Figure 1, i.e. after the extraction of the silicon wafers 04 from the composite material 01, the plastic films 03, 05 remain connected to the glass plate 02 in sections.

[0010] In most photovoltaic modules with the structure described above, the glass surface bonded to the plastic film is deeply structured to increase sunlight absorption. Known processes, for example, use a hot knife (JP2015110201 A) or a hot wire, which are placed on the glass and moved parallel to the glass surface. The wire or knife cuts through the plastic film, but is unable to remove the polymer from the recesses in the glass surface.

[0011] Another variant for removing plastic film from the glass plate uses microwave radiation. This is used to reduce the adhesion of the film to the glass plate by heating the radiation-absorbing silicon layer and, with it, the adjacent film via heat conduction. The silicon layer is arranged on the side of the film opposite the glass plate. (AIP Conference Proceedings 2681, 020002 (2022) Katayut Kamano et. al, “Glass separation process for recycling of solar photovoltaic panels by microwave heating”). However, this variant is very energy- and equipment-intensive and always requires the radiation-absorbing silicon layer. There is also a risk that the film layer will tear when peeled off due to the heat it receives instead of completely detaching from the glass plate.Another disadvantage is that after this step the silicon still has to be separated from the foil, whereby the handling of this material composite is more difficult than handling with a large-area carrier substrate.

[0012] There is therefore a need to remove plastic films from a carrier substrate, both defective films, such as those obtainable using the previously described process in PCT / DE2022 / 200078, and fully intact plastic films. Furthermore, the process and device should be designed with the lowest possible cost, energy, and equipment requirements and should also be applicable at stages of the recycling process where the existing layers of the product do not necessarily still need to include sufficient radiation-absorbing layers.

[0013] The object is achieved by a method according to claim 1 and a device used therefor according to claim 10. Claims relating thereto represent advantageous embodiments of the method and the device, respectively.

[0014] To solve the problem, at least the plastic film is removed from the carrier substrate using a removal device.

[0015] During the process according to the invention, the carrier substrate is mounted on a support surface with the surface opposite the surface containing the plastic film. The removal device comprises at least one rotatable roller, one of whose cover surfaces or the outer surface of the roller body is designed as a contact surface, and which is brought into physical contact with the plastic film and / or materials adhering to the plastic film, collectively also referred to as the surface to be removed, of the carrier substrate lying on the support surface.

[0016] At least a portion of the contact surface of the roller, hereinafter referred to as the effective contact surface, is positioned relative to a first portion of the carrier substrate, establishing physical contact between the effective contact surface and the surface of the layer to be removed, and is subjected to a contact force FA which has a component directed perpendicularly to the surface to be stripped.

[0017] In this position, the contact surface and the carrier substrate are moved relative to each other in a first section of the carrier substrate without breaking the physical contact between both surfaces, so that the plastic film is removed at least in the first section. The movement of the contact surface is effected by a rotation of the roller.

[0018] Depending on the shape of the roller body and the choice of contact surface, its rotation axis can be at a different angle to the surface of the carrier substrate to be decoated, as described in more detail below.

[0019] In contrast to the prior art, the method according to the invention for peeling off the plastic film enables the removal of the plastic film in the recesses of a deeply structured surface adjacent to the plastic film, such as that of the carrier substrate, and also of materials which are connected to the top side of the plastic film or adhere to it.

[0020] The surface or upper side of the plastic film is referred to as the surface of the plastic film which faces away from the carrier substrate. It is not necessary for no other materials to be present on this surface, since these can be removed together with the plastic film, particularly with this variant of the invention. Such materials can be, for example, wafer fragments in photovoltaic modules, the electrical contacts of the wafers and / or busbars, or other materials which may also be at least partially embedded in the plastic film. Unless otherwise described below, the method and device are intended to relate to the removal of the plastic film, regardless of whether it contains other materials or not.

[0021] Where the surface of the carrier substrate containing the materials to be removed is referred to below, this is referred to as the surface to be stripped. To distinguish it, the surface with which the contact surface is brought into physical contact is referred to as the surface of the layer to be removed, regardless of its surface quality and the components of the layer to be removed.

[0022] If the geometry of the contact surface prevents its entire surface from being brought into contact with the surface of the layer to be removed simultaneously, the section currently in contact is referred to as the "effective contact surface." According to the contact surface described below, which is provided by the outer surface of a roller, the effective contact surface is the section temporarily in contact with said surface as a result of the roller rolling. This means that the effective contact surface is merely a strip of the outer surface of the roller, which shifts across the outer surface with rotation.

[0023] According to the invention, the contact surface is provided by at least one roller, which is a component of the removal device. A roller, for example, is considered to be a cylindrical body which is mounted so as to be rotatable about its central axis. Truncated cone-shaped rollers can also be used for the process. To remove the layer to be removed, the contact surface of one or more rollers is first positioned relative to a first section of the carrier substrate, whereby both surfaces, the respective effective contact surface of the roller and the surface of the layer to be removed, are brought into physical contact. For effective decoating, it is desirable that the largest possible contact surface functions as the effective contact surface. A preferred physical contact for the process occurs when both surfaces are in 100% physical contact.Smaller surface areas are possible, even if this results in a loss of process efficiency. For example, at least 90%, preferably at least 80%, preferably at least 70%, or lower surface areas may be acceptable. When using the lateral surface as a contact surface, positioning is therefore preferably carried out such that the surface strip is effective over the entire length of the surface line. When using the cover surface, this preferably applies to the entire circular area.

[0024] If multiple rollers are used, all rollers involved in the removal process are arranged so that their effective contact surface is in physical contact with the surface of the layer to be removed. If the rollers have the same diameter, their axes of rotation can lie in a plane parallel to the carrier substrate. Deviations from this are possible, for example, if different effects are to be achieved with the rollers, if the surface lines of the rollers are not parallel to their central axis of rotation, or if the carrier substrate has a different surface texture in certain sections.

[0025] According to one embodiment of the method, the plastic film is removed using a group of rollers, with at least two rollers. The roller group and the carrier substrate are moved relative to one another in a direction of movement. The rollers are arranged side by side and one behind the other in such a way that the removal by the individual rollers overlaps in sections, viewed in the direction of movement. For the sake of clarity, the direction of movement will be referred to as the X-direction below.

[0026] The staggered arrangement of the rollers in a roller group depends, among other things, on the type of contact surfaces. The extent of the contact surfaces, measured perpendicular to the direction of movement, is greater than the width of the carrier substrate in this direction. To completely cover the substrate width, they are arranged offset laterally to one another and one behind the other. If the lateral surfaces form the contact surfaces, the two or more rollers can lie with their axes of rotation in a plane parallel to the carrier substrate or at least essentially parallel to this. In addition, their axes can have an angle other than 90°, based on the direction of movement of the carrier substrate. Angles of 45°, 50°, 55°, 60°, 65°, 70° or larger or smaller, or all intermediate values, can be used.Such an arrangement can be described as a herringbone arrangement. A similarly offset arrangement of the contact surfaces can also be used for the process variant in which the cover surfaces of the rollers are designed as contact surfaces. A combination of both variants is also possible. For further details of such arrangements, please refer to the figures and their descriptions.

[0027] When positioning the contact surface relative to the surface of the layer to be removed, various relative movement sequences are possible. For example, the contact surface can first be advanced onto the surface of a stationary carrier substrate. For the sake of simplicity, the direction of the advance movement is referred to here as movement in the Z direction, and the distance between the contact surface and the surface of the layer to be removed is referred to as the height. This is not intended to be a reference to the global coordinate system. Alternatively, the contact surface can first be advanced to a predefined Z position for the removal of the layer, and the carrier substrate can be fed into a plane essentially perpendicular to the Z direction, for example in the X direction. The physical contact is exerted by a contact force which has a component directed perpendicular to the surface to be coated.

[0028] The contact force required to remove the plastic film depends on various parameters. On the one hand, it should be high enough to ensure the desired complete removal of the carrier substrate, even in its surface depressions caused by roughness. On the other hand, the contact force should be low enough to avoid damage to the carrier substrate, which is detrimental to recycling, and to prevent contamination of the substrate with abrasion from the roller. The contact force therefore depends on various factors, some of which cannot be quantified, in particular the material and condition of the plastic film, as well as the material, size, and surface quality of the contact surface. The required contact force is therefore determined through testing and / or simulation.The contact force preferably acts essentially perpendicular to the surface to be decoated, in the Z direction according to the coordinates used above, since this directional component of the force in particular contributes to the removal of the plastic film.

[0029] In various embodiments of the invention, the contact force can be applied solely by the weight of the roller. Alternatively, the contact surface can be pressed onto the surface of the layer to be removed with a predefined force, for example, by means of a roller mount.

[0030] The removal occurs as a result of a relative movement between the contact surface and the surface of the layer to be removed, based on the rotation of the roller, under the influence of this contact force. The latter ensures both the maintenance of physical contact during rotation and the removal of the layer during the rotation of the roller. Depending on the orientation of the roller and thus the selected contact surface of the roller, the relative movement can be a rolling of the roller over the surface to be removed or a rotation of the top surface of the roller on the surface to be removed.

[0031] Under the influence of the force acting on the rotation axis and thus on the outer surface, the cylinder "rolls" over the surface. In this embodiment, the outer surface serves as the contact surface, with the rotation axis of the roller running essentially parallel to the surface in question, in this case the surface to be decoated. In addition to the contact force, the surface properties of the contact surface, particularly its ability to deform elastically, also influence the size of the effective contact area.

[0032] In alternative embodiments of the invention, an end face of the roller can also be used as a contact surface by aligning the roller's rotational axis substantially perpendicular to the surface to be stripped. In this case, the roller can have a reduced length, i.e., its cylinder can have a reduced height, which can optionally be less than the diameter of the cylinder, so that the roller functions as a turntable. Here, too, the relative movement occurs by means of the rotation of the roller, but a rotating end face of the roller equipped with bristles effects the removal of the layer.

[0033] Depending on the size of the layer to be removed and / or the roller, removal processes can be carried out with the same contact surface one after the other or with several contact surfaces arranged simultaneously and next to each other, which completely remove the layer from the carrier substrate.

[0034] According to various embodiments of the process, the plastic film can be removed using different rollers.

[0035] According to a first embodiment, the material is removed using a brush roller, the outer surface or one of whose cover surfaces is formed by the end surfaces of a large number of bristles arranged next to one another. To form the aforementioned contact surfaces, the outer surface or at least one cover surface, the bristles are arranged densely and of essentially the same length, either on the concentric support axis of the roller or on one of its cover surfaces, so that the end surfaces of the bristles form the required contact surfaces. Such a outer surface is not closed, but has many interruptions. The thickness of the bristles, the density of their arrangement and the course of the bristles towards their end surfaces determine the extent of the interruption of the outer surface.

[0036] The material of the bristles can be selected depending on the materials to be removed; for example, various metallic or plastic bristles can be used. The arrangement of the bristles relative to the base surface on which the bristles are arranged can also be selected differently. Typically, bristles are arranged essentially perpendicular to the base surface. Angles deviating from 90° can also be advantageous for various applications, whereby their angle to the base surface is preferably > 30°, more preferably > 40°, more preferably > 50°, more preferably > 60°, more preferably > 70°, more preferably > 80° and can also assume any value in between. Furthermore, the bristles can be essentially straight or bent in various ways.

[0037] According to one embodiment of the invention, the bristles can be designed in such a way that they form a mesh below the casing or cover surface.

[0038] A braided bristle arrangement is understood here to be an arrangement of bristles in which the free end surfaces lie next to one another, but the course of the bristles, starting from their base, is designed in such a way that, in a plan view of the contact surface formed by the bristles, it is no longer possible to identify which visible end surface of a bristle belongs to which base, i.e. how the bristle runs in the braided bristle. Such a braided bristle is obviously connected to more and less curved bristles, whereby the bends can follow a system or be arbitrary. A braided bristle can also be produced by means of a dense arrangement of bristles, whether random or systematic, or with strong or weak bends. An arrangement can be regarded as “dense” if the distance between the base points of the bristles, depending on their thickness, is less than or a single-digit multiple of the diameter of the bristles.A mixture of bristles of different thicknesses is also possible.

[0039] Surprisingly, it has been shown that the above-mentioned desired effects can be achieved with contact surfaces designed in this way. The brush roller can be used to completely remove the plastic films, even from roughened surfaces of the carrier substrate, without any subsequent processing. Furthermore, the surface of the carrier substrate is not damaged to a degree that would be significant for its reuse for the same purpose, nor is it contaminated by material abrasion from the brush. This is linked to the fact that such brush rollers have been observed to have a longer service life compared to brushes without mesh.

[0040] Furthermore, it is advantageous that components of the wafer layer do not interfere with the decoating process according to the invention. On the contrary, by appropriately selecting one or more brushes, which can optionally have different meshes, the entire wafer layer, i.e., including the contacts and optionally also including the busbars, can be removed in a single process step. Complex pretreatments can be eliminated.

[0041] The bristles of a brush roller can be designed in different ways. For example, the density of the bristles can be varied, bristles of different thicknesses, randomly or systematically curved bristles, bristles arranged in groups and / or bundles, bristles arranged in twisted bundles, or other designs. Alternatively or additionally, when using multiple rollers or in several successive process steps, different brush rollers can also be combined in one process. In contrast to a contact surface, which is formed from the adjacent end surfaces of bristles and is thus interrupted or "open", a closed contact surface can also be used. A "closed" outer surface or cover surface of a roller is a surface known from geometry as a cylinder or, alternatively, a truncated cone.Their optionally closed cover surfaces can optionally have elliptical instead of circular cover surfaces.

[0042] With such a roller having closed contact surfaces, the plastic film is removed from the carrier substrate according to a further embodiment of the invention by peeling off the plastic film. The closed contact surface is also brought into surface contact with the plastic film and a contact force is applied to the surface of the plastic film by means of the contact surface such that the static friction force between the two contacting surfaces is greater than the adhesion force between the plastic film and the carrier substrate. Both forces can be determined by known calculations or measurements. As a result of the greater static friction force between the contact surface and the surface of the plastic film, the adhesion between the plastic film and the carrier substrate is overcome and the film detaches from the carrier substrate.

[0043] As is well known, the static friction force is proportional to the contact force exerted by the removal device on the plastic film, with the proportionality factor being the static friction coefficient determined by the material combination. As soon as the contact surface begins to slide on the plastic film, the static friction force is zero and a sliding friction force is applied:

[0044] FH - Fh.max - po x FA where FH is the static friction force, Fh.max is the maximum achievable static friction force at the time immediately before the two materials slide, or the static friction coefficient, and FA is the contact force that can be applied in a defined manner using the removal device. This functional relationship results in the modifications to the method and device described below, allowing adaptation to different material combinations and conditions of the coating and carrier substrate.

[0045] As already described above, the contact force can be the weight applied by the removal device or a different, freely selectable, and specifically applied force. It is advantageous here if the roller is held with suitable holding devices and its contact surface is pressed against the layer to be removed.

[0046] In addition to varying the contact force, static friction can be influenced alternatively or additionally by the material combination of the contact surfaces. For this purpose, the material of the contact surface can be specifically selected, as described in more detail below for the device.

[0047] In some cases the adhesion force is very high, e.g. over 50 N / cm 2 up to over 100 N / cm 2In these and other cases, it may be advantageous to coat the roller, which has a closed contact surface, with a material such as rubber, which has a high coefficient of static friction compared to other materials such as metals, instead of increasing the contact force on the carrier substrate. Furthermore, a rubberized roller can prevent contamination of the carrier substrate with, for example, metallic particles due to abrasion from the metallic roller. This is of interest for the recycling of low-iron solar glass.

[0048] If there are other materials and / or objects on the surface of the plastic film to be removed that do not have direct contact with the carrier substrate, these can be removed in this embodiment of the process, optionally also when using a brush roller, before the plastic film is removed. In a plastic film composite with the layer structure described above, these could be, for example, the so-called busbars.

[0049] The busbars typically consist of tinned copper strips, which in this case are soldered to the surfaces of the silicon wafers of the photovoltaic module, thus establishing an electrical connection between the wafers. After removal of the wafers, for example, using the method described above according to PCT / DE2022 / 200078, sections of the electrical connections may remain on webs of the plastic film that run between the wafers and are shown in Fig. 1 as thickened sections of the plastic film.

[0050] Under unfavorable conditions, the busbars can cut into the surface of a roller, especially if it is coated with an elastic material, thus hindering the removal process and / or damaging the roller's surface layer. Furthermore, the properties of the plastic films applied to carrier substrates vary greatly depending on the product generation, manufacturer, or degree of aging. Therefore, the process parameters, such as contact pressure, rotation speed of the roller or turntable, or roller feed rate, are not equally applicable to all carrier substrates.

[0051] In these or other situations, a pretreatment can be carried out which removes at least a portion of the plastic films, particularly in the case of a plastic film composite, and with it, if applicable, also the underlying busbars. Various methods are suitable for this. Preferably, the plastic film should remain largely intact over its entire surface as a result of the pretreatment and its thickness should be only slightly reduced in order to be able to carry out the subsequent removal process, particularly that with a closed contact surface, efficiently. According to one embodiment, this can be carried out, for example, using a band or wire saw or a roller milling machine or other known methods. The saw band or the wire or the milling machine is guided parallel to the glass surface.For example, the saw blade is supported by a large number of rollers which are arranged on the side of the saw blade facing away from the panel and which support the parallelism of the blade to the panel surface through the rollers.

[0052] The decoating process described above is suitable for effectively decoating large quantities of carrier substrates, whereby the steps described above can be integrated into a continuous process as is known from the treatment of carrier substrates.

[0053] A device for carrying out the method comprises at least the components described below.

[0054] - a substrate holder with a receiving surface for receiving a plate-shaped carrier substrate,

[0055] - a removal device with at least one rotatable roller, one of whose cover surfaces or the outer surface is designed as a contact surface according to the above description, in order to be brought into physical, planar contact with at least a portion of the surface of the layer to be removed of the carrier substrate arranged on the receiving surface,

[0056] - a positioning device which is designed and configured to position the at least one contact surface relative to the layer to be removed and to maintain and / or modify this relative position during a relative movement between the contact surface and the carrier substrate,

[0057] - a movement device for carrying out a relative movement between the at least one contact surface and the carrier substrate such that the contact surface remains in contact with the layer to be removed of the carrier substrate arranged on the receiving surface during the relative movement.

[0058] Various known devices can be used as substrate holders, provided they have at least one flat support surface of the required size, which is also capable of absorbing the weight of the carrier substrate and any additional contact force that may be introduced into the contact surface. For an optional continuous process for decoating a plurality of carrier substrates, the substrate holder can have multiple support surfaces, for example, a conveyor belt designed as a transport device, such as those known from continuous systems for substrate treatment.

[0059] According to the invention, the removal device comprises the previously described rotatable roller, whose cylindrical or truncated cone-shaped roller body provides the contact surface or contact surfaces formed by the outer or cover surface with their properties as described above. It also comprises the components required for holding the one or optionally more rollers in the above-described position relative to the carrier substrate.

[0060] The positioning device comprises drives and their control, which are in communicative operative connection with the holder of the one or more rollers of the removal device and / or with the receiving surface of the substrate holder in order to carry out a feed of at least one of the rollers relative to the receiving surface of the substrate holder and to maintain this feed position during a relative movement between the receiving surface and the holder of the at least one roller during the removal of the layer to be removed. Furthermore, the positioning device is configured to generate a contact force which acts on the contact surface and in the direction of the receiving surface. The movement device of the device according to the invention is designed to carry out the previously described relative movements of the contact surface relative to the layer to be removed, which are necessary for the removal of the plastic film layer.These are, in particular, rotational movements of the contact surface while it is in contact with the layer to be removed. Furthermore, the required relative movements of the receiving surface can occur in a direction parallel to the contact surface being removed.

[0061] According to one embodiment of the device, the removal device comprises one or more rollers or one or more turntables. Optionally, a combination of both configurations can also be advantageous. A turntable is usually a circular, rotatable disk, which can be viewed as a roller whose height is significantly smaller than its diameter. The turntable is mounted so as to be rotatable about its center, similar to the roller, and has a flat or optionally curved underside. The turntable is aligned relative to the surface of the substrate to be decoated such that its axis of rotation is directed essentially perpendicular to the surface of the test substrate to be decoated, and its contact surface is formed by the underside of the turntable facing the carrier substrate, also referred to here as the base surface.

[0062] A substantially vertical alignment includes such deviations from the vertical direction in which a surface of the turntable of at least 90%, preferably at least 85%, more preferably at least 80%, more preferably at least 75%, more preferably at least 70% is still in physical contact as a contact surface with the surface of the carrier substrate to be decoated, forming an effective contact surface.

[0063] When using at least one roller, the detachment of the plastic film can be adapted to the parameters of the carrier substrate, in particular the size of the carrier substrate or its sections and / or the contact surface of the roller, by means of the diameter of the roller or the use and arrangement of several rollers.

[0064] The use of turntables allows for various rotational movements for removing the plastic film. The turntable's axis of rotation can be centered or eccentric.

[0065] The use of multiple rollers and / or turntables, optionally mounted separately, supports the removal of plastic film from a larger surface in a single operation. Separate mounting of the contact surfaces allows not only optimal positioning of the contact surfaces on the layer to be removed, but also local adjustment of the contact force.

[0066] For example, in a continuous stripping process using such a removal device, sections that have not been completely stripped can be reworked during the process.

[0067] The device can comprise additional auxiliary devices to improve the removal of the plastic film and, if applicable, its components. For example, an auxiliary roller can be arranged in front of the roller encompassing the contact surface. This auxiliary roller is not driven and presses or is pressed onto the composite component directly in front of the removing roller. The auxiliary roller can rotate freely, i.e., be movably mounted, and prevent the carrier substrate from being lifted perpendicular to the receiving surface in the event of a broken carrier substrate.

[0068] Furthermore, the device can comprise means for cleaning the surface of the plastic film and / or the contact surface. Cleaning these surfaces can significantly improve the adhesion of the closed contact surfaces or reduce contamination of the open contact surfaces of the brush rollers, thus increasing their effectiveness. Such means can, for example, be fans directed at the relevant surfaces. Optionally or additionally, suction devices and / or cleaning brushes can also be used.

[0069] In summary, the method according to the invention or the device used therefor and its embodiments can be described as follows:

[0070] • The method is suitable for decoating various carrier substrates, for example glass plates, wherein the coating contains at least one plastic film, for example a polymer, which has a common surface with the carrier substrate.

[0071] According to the invention, the plastic film is peeled or rubbed off the carrier substrate using at least one rotating tool without the plastic film having to be cut beforehand.

[0072] • The rotating tool for the removal process can comprise one or more rollers, preferably one or more brush rollers or rollers, which optionally have a rubberized coating.

[0073] • The rotating tool may alternatively or additionally comprise one or more rotating plates, preferably one or more brush or rubberized rotating plates.

[0074] • The carrier substrate to be stripped can be part of a photovoltaic module.

[0075] • Before the removal process, additional layers can optionally be removed by cutting processes using a band saw, a wire saw or a roller milling machine that do not have direct contact with the carrier substrate.

[0076] • The further layers may contain metal busbars of a photovoltaic module.

[0077] • The band saw can be positioned and stabilized by spring-loaded or pneumatically or hydraulically mounted rollers.

[0078] • Suction pipes equipped with longitudinal slots, which are arranged parallel to the roller or to the surface of the carrier substrate, optionally to the saw band, can be used to remove the removed material.

[0079] * The suction pipes can be used to cool the saw blade or the peeling tool.

[0080] * One or more rotating brushes remove polymer particles on the rotating tool, which are then captured and transported away by the suction pipes.

[0081] * The coated carrier substrate is positioned stationary relative to a moving, rotating removal tool, optionally to a moving band saw, on a support surface.

[0082] The method according to the invention and various embodiments thereof will be explained with reference to the attached figures using a roller as an example, but not in a restrictive manner. A person skilled in the art would combine and / or supplement the features of the method and a device usable therefor, which are evident from the description, in further embodiments, as far as this seems appropriate. The accompanying drawings show in

[0083] Fig. 1 a process for separating recyclable materials in a

[0084] Composite component according to PCT / DE2022 / 200078,

[0085] Fig. 2 shows a method for removing a plastic film by means of a closed contact surface formed by the outer surface of a roller,

[0086] Fig. 3 a method for pretreating the carrier substrate by

[0087] Removal of components of the wafer layer,

[0088] Fig. 4 shows an embodiment of the method according to Fig. 2,

[0089] Fig. 5A, Fig. 5B embodiments of brush rollers and their arrangement on a test substrate,

[0090] Fig. 6 Embodiments of the arrangement of brush rollers on a test substrate and

[0091] REPLACEMENT SHEET (RULE 26) Fig. 7A, Fig. 7B Embodiments of the brush rollers according to Fig. 6 in various arrangements over a test substrate.

[0092] The drawings depict the method and device only to the extent necessary for understanding the invention. They make no claim to completeness or scale.

[0093] In the following description, the carrier substrate corresponds to a glass plate but is also applicable to other, for example other, optionally transparent and opaque carrier substrates.

[0094] With the method according to Fig. 2, the carrier substrates 02 obtained with the method described in PCT / DE 2022 / 200078 (Fig. 1), which have plastic films 03, 05 on one surface, can be decoated by means of the method according to the invention.

[0095] For this purpose, the "upper" plastic film 03 directly adjacent to the carrier substrate 02 is peeled off by means of a roller 07, optionally several of them, while the second plastic film 05, which covers the opened pockets in which the wafers (Fig. 1, reference numeral 04) were previously embedded, remains on the upper plastic film 03. If several rollers (not shown) are used, they can be arranged side by side, along a line running in the viewing direction, or distributed over a surface. Other arrangements are also possible.

[0096] The composite component 01 is placed on a suitable holding device comprising a receiving surface 06 which receives the composite component 01 and supports it flatly. The receiving surface 06 is provided, for example, with a table. This can be designed with a flexible, for example rubberized surface (not shown). A roller 07, the outer surface of which forms the usable contact surface 19', is pressed onto the composite component with a freely selectable contact force FA, so that the composite component 01 is clamped between the receiving surface 06 and the roller 07. Only that section of the outer surface which is in physical contact with the composite component 01 acts as an "effective" contact surface 19" (shown in dashed lines) in the situation shown. This is a surface line of the roller 07 with a narrow width, depending on the deformability of the roller surface and the contact force FA.

[0097] The roller 07 is then rotated about its longitudinal axis 16 (running in the viewing direction), represented by a first directional arrow 08, and simultaneously moved over the composite component 01, represented by a second directional arrow 09. During the removal process, the plastic film 03 is not cut, but rather peeled or rubbed off. In the following, "removal" always refers to a process in which the polymer is not cut. Tearing of the plastic films 03, 05 is possible and to be expected, especially when using a turntable (not shown).

[0098] In the case of a broken (not shown) carrier substrate 02, it may be advantageous to press another roller (not shown), designated as an auxiliary roller for differentiation, which is not driven, onto the composite component directly in front of the peeling roller 07 and to allow it to run freely, i.e., movably mounted, in the transport direction 09 of the peeling roller 07. The auxiliary roller prevents the composite component 01 from being lifted perpendicular to the receiving surface 06 in the event of high adhesion forces between the plastic film 03 and the carrier substrate 02.

[0099] Alternatively, the carrier substrate 01 can also be moved in a direction of movement (not shown) which runs opposite to the transport direction 09 in order to continue the removal process over the entire surface of the carrier substrate.

[0100] Fig. 3 shows a pretreatment of the carrier substrate, with which a

[0101] The existing plastic film composite 05, which may include busbars (not shown), is removed from the plastic film 03. This can be done, for example, using a saw blade 10. The saw blade 10 is moved parallel to the surface of the carrier substrate 02, for example from the plane of the drawing, via two drive rollers (not shown), whose drive axes are parallel to the plane of the drawing. Several spring-loaded rollers 11 are used to position the height and stabilize the saw blade. The axes of rotation 18 of the rollers 11 are arranged in a plane parallel to the carrier substrate. As an alternative to spring bearings, pneumatic or hydraulic bearings can be used.

[0102] To remove the plastic film composite 05 and the current busbars, the saw band 10 including its drive rollers together with the rollers (11) are moved in the direction (12).

[0103] The positioning of the saw blade 10 with the spring-loaded rollers 11 is designed such that, although all busbars are removed, there is no contact, or no significant contact, between the saw blade 10 and the glass surface, i.e., contact that would result in the plastic film 03, 05 being removed across the entire surface. This prevents the plastic film 03, 05 from remaining only in the recesses of the structured glass after pretreatment, thus preventing it from providing a sufficient contact surface for the static friction of the optionally rubberized roller 07.

[0104] As an alternative to the direction of movement 12, a conveyor belt can also be used instead of the table 06. Consequently, the composite component 01 is moved and not the band saw or the roller conveyor. Transport by conveyor belt is technically easier to implement and requires less space, since the pre-treatment in Figure 3 and the subsequent separation in Figure 2 can take place directly one after the other or the same conveyor belt is used instead of two tables 06 arranged one behind the other. Although the saw band 10 can pull the removed material with it and thus remove it from the area of ​​the glass, additional extraction at the site of the sawing process increases the service life of the saw band 10 by removing the current busbars at an early stage. The extraction (not sketched) can, for example, be provided by a slotted pipe directly before and after the saw band 10. The pipes are arranged parallel to the saw band 10.The air flow of the extraction also serves to cool the saw band 10 and the rollers 11 .

[0105] To remove the material peeled from the roller 07, a slotted suction pipe 13, as shown in Fig. 4, can be used, similar to the method used with a band saw, particularly when a single roller 07 is used and the plastic film 03, 05 is removed in continuous, large pieces. It may also be advantageous to cool the roller 07 with the air flow from the suction pipe.

[0106] In some cases, the plastic film 03,05 disintegrates into small particles during the removal process outlined in Fig. 2, which can accumulate on a rubberized roller and thus reduce the coefficient of static friction. Fig. 4 shows the use of a rotating brush roller 14 in an application according to Fig. 3. The brush roller 14 permanently cleans the roller 07, optionally a roller with a closed contact surface 19' and optionally rubberized, by brushing in opposite directions, represented by a third directional arrow 15. The effective contact surface 19" is in turn only that strip of the outer surface of the roller 07 at which the roller 07 is in contact with the composite component 01, or after removal of the plastic film 03 with the carrier substrate 02. The brushed-off particles (not shown) can then be removed through a slotted suction pipe 13.

[0107] Fig. 5A and Fig. 5B illustrate alternative embodiments of the roller 07, whose contact surfaces 19' are formed by the end surfaces 23 of a plurality of metallic bristles 20, the end surfaces 23 together forming the outer surface of the roller 07. The bristles 20 are arranged with their base points (not visible) on the roller core 21. The roller core 21 has a central passage 22 by means of which the rollers 07 can be rotatably mounted.

[0108] The bristles 20 of both brush rollers form a mesh such that their free end surfaces 23 visible in the figure cannot be clearly assigned to their base points, in that all bristles 20 or at least the vast majority of them are bent several times and arranged densely packed on the roller core 21.

[0109] The curved shape of the bristles 20 is configured differently on both rollers 07. The bristles 20 of the roller 07 of Fig. 5A are arranged individually and are very thin. Their thickness is, for example, in the range from 0.1 to 2 mm, preferably from 0.1 to 1 mm, more preferably from 0.1 to 0.5 mm. It can optionally also assume other values. Furthermore, they are curved multiple times and irregularly over their entire length, i.e., without a recognizable common structure, while having a clearly identifiable direction of extension over their entire length.

[0110] The bristles 20 of roller 07 in Fig. 5B have a thickness that is many times greater than that of the bristles in Fig. 5A, for example, 5 to 10 times, or 5 to 20 times. This thickness can optionally also be adjusted to other values. The bristles 20 are arranged in tufts 24, with each tuft 24 individually twisted so that the free end surfaces 23 have an angle of impact other than 90° with the imaginary surface formed by the end surfaces, which represents the contact surface 19.

[0111] 5A and 5B that contact surfaces 19 designed in this way are not completely closed, but open. Other embodiments of the bristles and the brush rollers with other open contact surfaces which nevertheless form the outer surface of a brush roller are possible. Fig. 6 shows two embodiments of brush rollers in their application on the surface of a plastic film 03 of a test substrate 02 that is to be removed. Both embodiments are arranged on the same test substrate 02 solely for the sake of better comparability. The brush roller shown on the left is shown with an axis of rotation 16 lying parallel to the receiving surface 06 of the holding device and thus also to the surface of the test substrate 02. Its contact surface 19' is formed by the outer surface of the roller 07, i.e. in this embodiment by the plurality of adjacent end surfaces (not shown) of the bristles 20.The effective contact surface 19" is again the narrow strip of the lateral surface in contact with the surface of the plastic film 03. Furthermore, reference can be made to the explanations for Fig. 2 and Fig. 5, where the same reference numerals are associated with the same functions.

[0112] The brush roller shown on the right in Fig. 6 comprises a short roller 07, compared to the version shown on the left, which is arranged on the surface of the plastic film 03 such that the rotation axis 16 is perpendicular to said surface. In this case, the bristles 20 are arranged on the lower cover surface of the roller 07, so that it functions like a turntable and the entire contact surface 19' of the roller 07 forms the effective contact surface 19". For the rest, reference is made to Fig. 2, where the same reference numerals again represent the same functions.

[0113] Fig. 7A and Fig. 7B illustrate the use of a group of several rollers 07 for decoating a composite component consisting of a carrier substrate 02 and a plastic film 03. During decoating, the carrier substrate 02 is moved along a direction of movement 25 relative to the rollers 07 and is completely decoated in the process. The rollers 07 of both groups are arranged next to one another and, moreover, offset one behind the other in such a way that the entire carrier substrate can be decoated during one substrate pass in the direction of movement 25. The rollers are arranged next to one another in a direction perpendicular to the direction of movement and one behind the other in the direction of movement.

[0114] In Fig. 7A, two rollers 07 are arranged so that their axes of rotation 16 run parallel to the surface of the carrier substrate 02. They are arranged, for example, at the same angle α, measured between the axis of rotation 16 and a reference line falling perpendicular to the direction of movement, which is greater than 0° and less than 90°, e.g. approximately 30°. They are arranged next to one another in such a way that they cover the entire width of the carrier substrate 02 as the substrate passes through. For this purpose, they are offset from one another, which inevitably requires an offset behind one another, as can be seen from Fig. 7A. The section of the carrier substrate that has already been stripped of its coating in the substrate pass shown is shown with diagonal hatching.

[0115] In Fig. 7B, a group of three rollers 07, designed as a turntable (Fig. 6, right-hand illustration), is used. Their rotation axes 16 are perpendicular to the surface of the carrier substrate 02 and are again offset from one another, i.e., arranged side by side and one behind the other, such that the decoating areas overlap, viewed transversely to the direction of movement 25 of the carrier substrate. The already decoated section of the carrier substrate 02 is again shown with diagonal hatching.

[0116] Alternative designs to the devices and methods illustrated and described above are possible. For example, cylindrical milling cutters can be used as an alternative to a band saw. Instead of one or more rubberized rollers, rubberized rotary plates or brushes can also be used, as long as the static friction force exceeds the adhesive force, allowing a material removal process to occur.

[0117] For some plastic films 03, 05, heating, for example via a heatable receiving surface 06 or an infrared lamp (not shown), can be advantageous to reduce the adhesion forces or to facilitate the removal process.

[0118] The above explanations concerning the auxiliary roller, the rubber coating of the roller and the heated receiving surface 06 are also applicable analogously to other embodiments of the method and the device, but apparently not to the use of brush rollers and / or to other embodiments of the composite components to be decoated.

[0119] The method described above and the device used for it can also be used for other coated substrates and, in addition, for other

[0120] Substrates are applicable where the conditions regarding the force ratios required for removal, as described above, can be established.

Claims

Claims 1 . A method for removing a film-like plastic coating present on a surface of a plate-shaped carrier substrate, hereinafter also referred to as plastic film, comprising the following process steps: - Storage of the carrier substrate with the surface on a receiving surface which is opposite to the surface containing the plastic film, - Providing a removal device comprising at least one rotatable roller, one cover surface or the outer surface of the roller body of which is designed as a contact surface, which is brought into physical contact with the plastic film and / or materials adhering to the plastic film, collectively also referred to as the surface to be removed, of the carrier substrate lying on the receiving surface, - positioning the contact surface relative to a first portion of the carrier substrate and establishing physical contact between at least a portion of the contact surface, referred to here as the effective contact surface, and the surface of the layer to be removed, - Applying a contact force to the effective contact surface that is directed perpendicularly to the surface to be decoated, - moving the contact surface and the carrier substrate relative to each other in a first section of the carrier substrate without breaking the physical contact, and removing the plastic film at least in the first section, - whereby the movement of the contact surface occurs through a rotation of the roller.

2. Method, wherein the contact force is introduced due to the weight of the at least one roller or the at least one contact surface is pressed with a defined force onto the surface to be decoated.

3. Method according to one of the preceding claims 1 to 2, wherein the removal of the plastic film is carried out by brushing by means of a brush roller, the outer surface or one cover surface of which is formed by a plurality of adjacent end surfaces of bristles.

4. Method according to one of the preceding claims 1 to 2, wherein the removal of the plastic film is carried out by peeling by means of a closed outer surface or cover surface of the roller as a contact surface, wherein the contact force is greater than the adhesion force between the plastic film and the adjacent surface of the carrier substrate, 5. The method according to claim 4, wherein the static friction force between the outer surface and the surface of the plastic film is adjusted by the choice of the material of the contact surface.

6. Method according to one of the preceding claims, wherein further materials and / or objects present on the surface of the plastic film are removed in a pretreatment step.

7. Method according to one of the preceding claims, wherein the removal of material from a carrier substrate is carried out by means of a roller group with at least two rollers, in that the roller group and the carrier substrate are moved relative to one another in a direction of movement and the rollers are arranged next to one another and one behind the other in such a way that the removal by the individual rollers, viewed in the direction of movement, overlaps in sections.

8. A method according to any one of the preceding claims, wherein fragments of the ablated materials are removed from the surface of the carrier substrate by means of blowing or suction.

9. Method according to one of the preceding claims 1 to 3, wherein further materials and / or objects present on the surface of the plastic film are removed with a brush roller together with the plastic film or in a Pretreatment step must be removed.

10. Method according to one of the preceding claims, wherein the removal of the plastic films from several carrier substrates takes place in a continuous process. 11 . Device for carrying out the method according to one of the preceding claims, comprising the following components: - a substrate holder with a receiving surface for receiving a plate-shaped carrier substrate, - a removal device comprising at least one rotatable roller, of which a cover surface or the outer surface of the roller body is designed as a contact surface in order to be brought into surface contact with the surface of the layer to be removed of the carrier substrate lying on the receiving surface, - a positioning device which is designed and configured to position the at least one contact surface relative to the receiving surface and to maintain and / or modify this relative position during a relative movement between the contact surface and the receiving surface, - a movement device for carrying out a relative movement between the at least one contact surface and the receiving surface such that the contact surface remains in contact with the layer to be removed from a carrier substrate arranged on the receiving surface during the relative movement.

12. Device according to the preceding claim 11, wherein the positioning device is designed such that the at least one contact surface can be subjected to a defined contact force.

13. Device according to one of the preceding claims 10 or 11, wherein the at least one contact surface is formed by a closed outer surface of the roller, here also referred to as a closed contact surface, or by the outer surface or a cover surface of a roller, which is formed by a plurality of adjacent end surfaces of a mesh forming bristles are formed, here also called brush roller, 14. Device according to one of claims 11 to 13, wherein the static friction force between the closed contact surface and the surface of the plastic film can be modified by the choice of the material of the contact surface.

15. Device according to one of claims 11-14, wherein the device further comprises: - a cleaning device with a blower and / or a suction device and / or a cleaning brush, designed and configured to remove dissolved particles of the plastic film or materials present thereon from the surface of the carrier substrate and / or from a roller, and / or - an auxiliary roller which is movably mounted in front of the roller having the contact surface.

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