ATTACHMENT DEVICE, COOLING ROLLER UNIT AND LIFTING SYSTEM

Description

[0001] The invention relates to an application device for electrostatically applying a film to a cooling roller, a corresponding cooling roller unit and a stretching system with such a cooling roller unit.

[0002] In the production of thin plastic films, a film of molten plastic is first applied to a cooling roller, where it cools and solidifies. To ensure homogeneous cooling and thus homogeneous material properties, it is necessary that the film lies evenly across its entire width and continuously along its length on the cooling roller.

[0003] To prevent film deformation caused by mechanical application methods, it is known to generate a high-intensity electric field near the cooling roller surface using electrodes, which the film must pass through. Due to the electric field, the polar molecules of the film align, and the surface of the cooling roller becomes electrically charged. This creates an electrostatic attraction between the film and the cooling roller, causing the film to adhere to the cooling roller uniformly and automatically.

[0004] However, generating such a strong electric field requires a high voltage of 9 kV or more at the electrodes, which can lead to arcing between the electrodes and the cooling roller. Such arcing damages the surface of the cooling roller and also reduces the quality of the film produced.

[0005] JP H11-188777 discloses a casting unit with a feeder. The feeder uses a single wire that can be unwound on one side and wound on the other, and is charged with high voltage.

[0006] German patent DE 196 53 749 A1 discloses a casting unit with a positioning device. The positioning device has two electrodes designed as metal strips. The electrodes are connected to the same power source.

[0007] JP 2009-234194 A describes a positioning device in which a predetermined tension on the wire is ensured.

[0008] It is therefore an object of the invention to provide a positioning device, a cooling roller unit and a stretching system in which spark discharges are reduced.

[0009] The problem is solved by a device for electrostatically applying a film to a cooling roller, comprising a first coil unit, a second coil unit, an application area located between the coil units, a high-voltage source, and at least two electrodes, wherein at least the first electrode of the at least two electrodes is ribbon-shaped. The electrodes extend from the first coil unit to the second coil unit in the application area, and both electrodes are energized by the high-voltage source. One, several, or all of the electrodes are movable in their longitudinal direction between the first coil unit and the second coil unit.

[0010] By using two ribbon-shaped electrodes, both subjected to high voltage, a homogeneous electric field is generated, exhibiting particularly high field strengths, especially maximum field strengths, at the point where the film comes into contact with the cooling roller. This focusing of the electric field allows the high voltage to be reduced compared to other solutions to achieve the same field strengths. Reducing the high voltage at the electrodes also reduces the tendency for flashovers, thus causing fewer flashovers or preventing them altogether. Furthermore, deposits on one, several, or all electrodes that impair the quality of the electric field can be removed.

[0011] For example, high voltage has a voltage between 5 kV and 10 kV, specifically between 7 kV and 9 kV. High voltage can even reach up to 20 kV.

[0012] In one embodiment, the second electrode of the at least two electrodes is also ribbon-shaped or wire-like, in particular a wire, which can further improve the homogeneity of the electric field.

[0013] In one embodiment, a third electrode is provided, wherein the third electrode is ribbon-shaped or wire-like, in particular a wire. The third electrode further increases the homogeneity of the electric field.

[0014] For example, the electrodes run parallel to each other, resulting in a very homogeneous electric field.

[0015] Each of the two electrodes can have two faces, with one of their faces facing each other. This further increases the homogeneity of the electric field.

[0016] The side surfaces run parallel to each other.

[0017] In one aspect, the electrodes in the application area have a distance of 3 mm to 15 mm, in particular 5 mm to 10 mm from each other, which results in a particularly good focusing of the electric field.

[0018] For example, the electrodes have the same width, which further increases the homogeneity of the electric field. Different widths are also conceivable, which can influence the location of the maximum field strengths.

[0019] The width of the electrodes can range between 3 mm and 15 mm, in particular greater than or equal to 4 mm and less than 13 mm, thereby achieving very homogeneous electric fields.

[0020] In order to adapt the electrodes to the conditions of the cooling roller unit, the electrodes can be offset in the direction of their width or arranged flush.

[0021] For example, the direction of the width corresponds to the radial direction of the roller.

[0022] In one embodiment, at least one rotatable coil is provided in the first and second coil units, on which one, several or all of the electrodes are partially wound.

[0023] For example, for each of the electrodes in each of the coil units, a rotatable coil is arranged on which the corresponding electrode is partially wound.

[0024] In particular, at least one of the rotating coils is driven.

[0025] In one embodiment, one, in particular the second, electrode or several of the electrodes are static, particularly wherein a mechanical clamping device is provided in the second coil unit, wherein the one or more static electrodes in the second coil unit are attached to the clamping device and are fixed in position in the first coil unit. In this way, the complexity of the application device is reduced.

[0026] In one embodiment, at least one of the coil units, in particular both coil units, is provided with a voltage supply device that electrically connects the electrodes to the at least one high-voltage source, thereby ensuring reliable application of high voltage to the electrodes.

[0027] For example, a common high-voltage source is provided for the two coil units, or each coil unit has a separate high-voltage source.

[0028] In one embodiment, the voltage supply device has a roller along which the first electrode is guided, and / or the voltage supply device has an arc-shaped channel along which the second and / or the third electrode is guided. This enables reliable and space-saving contacting of the electrodes.

[0029] For example, one outside of the barrel describes a circular sector.

[0030] To prevent unwanted vibrations of the electrodes, the second coil unit has a damping device designed to dampen vibrations of the electrodes in the contact area.

[0031] The electrodes are led out of the corresponding coil unit, for example, by the damping device.

[0032] The vibrations to be damped have, in particular, an amplitude perpendicular to the side surfaces of the electrodes, in the direction of the width of the electrodes and / or are torsional vibrations around the longitudinal axis of the electrodes.

[0033] For example, the damping device includes a damping roller whose axis of rotation is perpendicular to the longitudinal direction and perpendicular to the direction of the width of the electrodes, wherein the damping roller is movably mounted in the direction of the width and rests on an edge of each of the electrodes, in particular on the edge facing away from the cooling roller. Thus, a damping device with only one damping roller can be implemented.

[0034] Alternatively or additionally, the damping device has two damping rollers whose axes of rotation are perpendicular to the longitudinal direction and parallel to the direction of the electrodes' width, with each electrode bearing against one of the damping rollers. This ensures that each electrode is damped separately, preventing the electrodes from influencing each other.

[0035] The damping rollers are located particularly against the side surfaces of the electrodes.

[0036] The two electrodes, for example, run between the two damping rollers.

[0037] In one embodiment, the contact device has several insulating devices, in particular insulating tubes, insulating sleeves and / or insulating sleeves, which extend from the associated coil unit to the contact area, wherein the electrodes pass through the insulating devices, and in particular wherein at least one insulating device is provided for each electrode on each of the coil units. The insulating devices reliably prevent spark discharges outside the contact area.

[0038] For example, the insulating devices are made of polyetheretherketone (PEEK), in particular of tempered polyetheretherketone.

[0039] The insulating devices enclose the electrodes at least on the edge facing the cooling roller.

[0040] In one embodiment, the insulating devices are attached to the damping device in a vibration-damped manner in order to minimize vibrations of the electrode guided therein.

[0041] In a further embodiment, at least one of the electrodes is subjected to a low voltage, in particular in addition to the high voltage, whereby the electrode subjected to the low voltage heats up and thus deposits or condensate on the electrode are reduced, since such deposits or condensate mainly form on cold surfaces.

[0042] For example, due to the low voltage, an electric current can develop between the two coil units via each of the electrodes. In particular, the electrodes are not grounded, so the current stops if an electrode breaks.

[0043] Low voltage, for example, has a maximum voltage of 150 V, for example between 60 V and 130 V, especially 120 V. The current generated by the low voltage can have a current intensity between 1 A and 8 A.

[0044] For example, the connection device includes a low-voltage power source. The high-voltage power source and the low-voltage power source can be combined into a single device.

[0045] The problem is further solved by a cooling roller unit (also called "casting unit"), at least comprising a slot die, a cooling roller and a feed device as previously described, in particular wherein the cooling roller is grounded.

[0046] The applied high voltage and the grounding of the cooling roller create a small electric current, called pinning current.

[0047] At a high voltage of 20 kV, the current, for example, is in the range between 25 mA and 30 mA. At a high voltage of 9 kV, a current of approximately 9 mA to 12 mA can occur.

[0048] Should an electrode break, the high-voltage source is switched off. A break in the electrode can be detected by edge detection.

[0049] The advantages and features described for the attachment device apply equally to the cooling roller unit and vice versa.

[0050] The electrodes can be at least as far from the cooling roller as the thickness of the film, for example at least 2 mm and / or at most 20 mm.

[0051] Furthermore, the task is solved by a stretching plant for producing a film, in particular a transverse, longitudinal and / or simultaneous stretching plant, with an oven and a cooling roller unit as described above.

[0052] The advantages and features described for the attachment device and / or the cooling roller unit apply equally to the stretching system and vice versa.

[0053] Further features and advantages of the invention will become apparent from the following description and from the accompanying drawings, to which reference is made. The drawings show: Figure 1 shows a drawing machine according to the invention with a cooling roller unit according to the invention in a schematic view; Figure 2 shows the cooling roller unit according to the invention. Figure 1 with a positioning device according to the invention in a schematic perspective view, Figure 3 a cross-section through the cooling roller unit schematically during operation, Figure 4 a perspective view of one of the winding units of the positioning device according to Figure 2Figures 5 and 6 show schematically different parts of the application device within the second and first coil units, respectively, as well as the electrode path within the corresponding coil unit. Figure 7 shows a perspective view of the electrodes exiting the insulating devices of the coil unit. Figure 4 Figure 8 shows a perspective view of a damping device of the coil unit according to Figure 4 Figure 9 shows a perspective view of the damping device of the Figure 8 Figure 10 shows a second embodiment of a damping device for a coil unit of an attachment device according to the invention, Figure 11 shows the damping device according to Figure 10 in a different view and partially opened, and Figures 12, 13 and 14 show a schematic section through a third, fourth and fifth embodiment of the attachment device during operation.

[0054] Figure 1Figure 1 shows a stretching machine 10 according to the invention for producing a film with a cooling roller unit 12 (also called "casting unit") and an oven 14. The stretching machine 10 is, for example, a transverse, longitudinal, and / or simultaneous stretching machine.

[0055] To produce the film, in the present example, the cooling roller unit 12 first generates a film 16 (also called "cast film") which is fed into the oven 14. In the oven 14, the film 16 is stretched in the longitudinal and / or transverse direction in a manner known per se, thereby producing a mono- or biaxially oriented film.

[0056] In Figure 2 The cooling roller unit 12 is shown in an enlarged schematic view.

[0057] The cooling roller unit 12 shown here comprises a slot nozzle 18, a cooling roller 20 and a positioning device 22.

[0058] The cooling roller 20 is cooled and is therefore also called a cooling roller or "chill roll".

[0059] The slot die 18 is arranged above the cooling roller 20 and is designed to continuously apply a polymer melt to the cooling roller 20, forming the film 16. The polymer used is, in particular, a polyethylene terephthalate (PET), but is not limited to this.

[0060] The film 16 is then evenly applied to the cooling roller 20 by means of the application device 22. The cooling roller 20 rotates in the view shown. Figure 2 counterclockwise. The film 16 produced in this way is finally, in the illustrated embodiment after about three-quarters of a rotation of the cooling roller 20, detached from the cooling roller 20, possibly cooled further and fed into the oven 14.

[0061] The application device 22 is an electrostatic application device and has two electrodes, namely a first electrode 24 and a second electrode 26, two coil units, namely a first coil unit 28 and a second coil unit 30, a low voltage source 31 and a high voltage source 32.

[0062] In the illustrated embodiment, the low-voltage source 31 and the high-voltage source 32 are designed as a single device. The low-voltage source 31 and the high-voltage source 32 can also be designed as separate devices.

[0063] The winding units 28, 30 are arranged in the axial direction of the cooling roller 20 in front of and behind the cooling roller 20, respectively. A contact area 34 is formed between the two winding units 28, 30, which, also viewed in the axial direction of the cooling roller 20, encompasses the area of ​​the film 16 on the cooling roller 20.

[0064] The electrodes 24, 26 are each both attached to each of the coil units 28, 30 and extend between the two coil units 28, 30, i.e. also through the application area 34.

[0065] In Figure 3 Figure 1 shows a schematic view of the cooling roller unit 12 in the axial direction of the cooling roller 20. For simplification, only the electrodes 24 and 26 of the application device 22 are shown.

[0066] In the first embodiment shown, the electrodes 24, 26 are ribbon-shaped, i.e., they have a width that is much longer than their thickness, in particular by an order of magnitude. Furthermore, their longitudinal length is orders of magnitude greater than their width.

[0067] The electrodes 24, 26 thus have two side surfaces extending longitudinally along the electrode 24, 26 and in the direction of its width, as well as two edges. One of the edges faces the cooling roller 20 and one of the edges faces away from the cooling roller 20. The direction between the edges of the same electrode 24, 26 is referred to as the direction of the width of the electrodes 24, 26.

[0068] In the first embodiment, the two electrodes 24, 26 have the same width, for example between 3 mm and 15 mm, in particular a width of more than or equal to 4 mm and of less than 13 mm. A width of 12.7 mm is conceivable, for example.

[0069] In the illustrated embodiment, the electrodes 24, 26 each have one of their side surfaces facing the other electrode 26, 24. The side surfaces, and thus also the two electrodes 24, 26, run parallel to each other, at least in the contact area 34.

[0070] The electrodes 24, 26 have a distance of 3 mm to 15 mm, in particular 5 mm to 10 mm, from each other in the application area 34.

[0071] The two electrodes 24, 26 are arranged flush with each other in the direction of their width, i.e. a connecting line of their edges is perpendicular to the side surface.

[0072] In particular, the direction of the width for one of the electrodes 24, 26 corresponds to the radial direction of the cooling roller 20.

[0073] The electrodes 24, 26 are arranged downstream of the slot die 18 in the direction of rotation of the cooling roller 20. For example, the electrodes 24, 26 have a distance to the cooling roller 20 of at least the thickness of the film 16, for example at least 2 mm. At most, they have a distance to the cooling roller 20 of 20 mm.

[0074] Electrodes 24 and 26 are supplied with a high voltage from the high-voltage source 32. The high voltage is, for example, between 5 kV and 10 kV, and in particular between 7 kV and 9 kV.

[0075] The cooling roller 20 is grounded, so that a strong electric field is created in the application area 34, through which the film 16 is guided.

[0076] In addition, a small electric current develops, called the pinning current. At a high voltage of 20 kV, for example, the current is approximately 30 mA. At a high voltage of 9 kV, a current of approximately 12 mA can occur.

[0077] Should one of the electrodes 24 or 26 rupture, the high-voltage source is switched off. A rupture of one of the electrodes 24 or 26 can be detected by the high-voltage source via edge detection.

[0078] Likewise, at least one, and in particular both, electrodes 24, 26 are supplied with a low voltage by the low-voltage source 31. The low voltage is, for example, less than 150 V, in particular between 60 V and 130 V, for example 120 V. The high voltage and the low voltage are cascaded accordingly.

[0079] In Figure 4 The second coil unit 30 is shown open. The second coil unit 30 is located in relation to Figure 2 on the left side of the cooling roller 20.

[0080] The first coil unit 28 on the right side of the cooling roller 20 has an identical construction, only mirrored. Any differences will be noted separately.

[0081] The second coil unit 30 comprises a housing 36, a rotatable coil 38, a voltage supply device 40, a first deflection roller 42, a mechanical tensioning device 44, a second deflection roller 46, a damping device 48 and two insulating devices 50.

[0082] In Figure 5 The coil unit 30 is shown in a further simplified form, namely only the two electrodes 24, 26 and the components that guide the electrodes 24, 26 are shown. For example, the housing 36, the damping device 48 and the insulating devices 50 are not shown.

[0083] The first electrode 24 is partially wound on the rotatable coil 38 and runs from the rotatable coil 38 to the voltage supply device 40.

[0084] The voltage supply device 40 is electrically connected to the high voltage source 32 and has a roller 52 and an arc-shaped guide 54.

[0085] The roller 52 guides the first electrode 24 and thereby applies the high voltage provided by the high voltage source 32 to the first electrode 24.

[0086] The first electrode 24 then runs to the first deflection roller 42 and from there out of the coil unit 30 to the application area 34.

[0087] The second electrode 26 is attached to the clamping device 44 in the second coil unit 30. The clamping device 44 has a pull bolt 56 for this purpose, which is actuated by a motor 58 ( Figure 4 ) can be activated.

[0088] The second electrode 26 then runs to the voltage supply device 40. At the voltage supply device 40, the second electrode 26 runs along the path 54.

[0089] The barrel 54 has an arc-shaped outer surface for guiding the second electrode 26. For example, the arc-shaped outer surface describes a circular sector.

[0090] Through contact with the barrel 54, the second electrode 26 is subjected to the high voltage provided by the high voltage source 32.

[0091] The second electrode 26 then runs over the second deflection pulley 46, which brings it into a parallel arrangement with the first electrode 24. The two electrodes 24, 26 then extend from the second coil unit 30 through the contact area 34 and finally into the first coil unit 28, which in a reduced form is Figure 6 is reproduced.

[0092] The first electrode 24 runs in reverse order as described for the second coil unit 30, first over the first deflection roller 42, the roller 52 of the voltage supply device 40 and finally onto the rotatable coil 38.

[0093] The voltage supply device 40 of the first coil unit 28 is also electrically connected to the high-voltage source 32. However, it is also conceivable that each of the coil units 28, 30 has a separate high-voltage source.

[0094] The two rotatable coils 38 of the coil units 28, 30 can be driven. In this way, the first electrode can be moved between the first coil unit 28 and the second coil unit 30. For example, the first electrode 24 is unwound from the rotatable coil 38 of the first coil unit 28, passes through the contact area 34 into the second coil unit 30, where it is wound onto the rotatable coil 38 of the second coil unit 30.

[0095] Furthermore, the tension or mechanical stress of the first electrode 24 can be adjusted by means of the driven rotatable coils 38.

[0096] In contrast, the second electrode 26 in the illustrated embodiment is static. It enters the first coil unit 28 and is guided by the second deflection pulley 46 to the voltage supply device 40. The second electrode 26 is then fixed in position within the first coil unit 28 by means of an end piece 60. Thus, unlike the second coil unit 30, the first coil unit 28 does not have a clamping device 44.

[0097] The tension or mechanical stress of the second electrode 26 is set by means of the clamping device 44.

[0098] However, it is also conceivable that instead of the end piece 60 and the clamping device 44, rotatable coils are provided for the second electrode 26, similar to the rotatable coils 38 for the first electrode 24. In this way, the second electrode 26 is also designed to be movable.

[0099] For example, each electrode 24, 26 can have its own rotatable coil in each coil unit 28, 30.

[0100] It is also conceivable that several of the electrodes 24, 26 are wound onto the same rotatable coil 38. In this case, for example, a common rotatable coil 38 is provided which has different sections for the different electrodes 24, 26. The mechanical tension of the different electrodes 24, 26 can then be adjusted by a clamping device for each of the electrodes 24, 26.

[0101] As in Figure 4 As shown, the electrodes 24, 26 run from the coil units 28, 30 through the damping devices 48 and finally through the insulating devices 50 out of the coil units 28, 30.

[0102] The insulating devices 50 extend from the damping device 48 to the contact area 34, as also in Figure 2 can be seen.

[0103] In particular, the insulating devices 50 extend along that area of ​​the cooling roller 20 where no film 16 is applied.

[0104] In Figure 7 Figure 1 shows a perspective view of the end of the insulating devices 50, pointing towards the contact area 34. In the illustration, the electrodes 24, 26 emerge from the insulating devices 50 and then extend into the contact area 34.

[0105] The insulating devices 50 are, for example, insulating tubes, insulating sleeves and / or insulating sleeves. They have an elongated cross-section that is approximately rectangular. For example, the corners are rounded or the short sides are formed by arc-shaped sections.

[0106] The inner diameters of the insulating devices 50 in their longitudinal direction correspond to the width of the electrodes 24, 26, so that one electrode 24, 26 can be guided in one of the insulating devices 50.

[0107] In the illustrated embodiment, the insulating devices 50 completely surround the received electrode 24, 26 along their circumference.

[0108] However, it is also conceivable that the electrodes 24, 26 are not completely enclosed, as long as they are enclosed by the respective insulating device 50 in relation to each other and / or to the cooling roller 20.

[0109] The insulating devices 50 are made of a plastic, in particular polyetheretherketone (PEEK). Specifically, the PEEK is tempered. Insulating devices 50 made of tempered PEEK have proven to be particularly durable.

[0110] The insulating devices 50 are attached to the output of the damping devices 48 by means of a fastening device 74, as shown in Figure 8 can be seen.

[0111] The fastening device 74, for example, has vibration-damping elements 76, such as dampers made of elastic material, between which the insulating devices 50 are clamped. The clamping can be adjusted, for example, by means of a screw.

[0112] The damping devices 48 are provided on a boom 62, which extends from the housing 36 of the respective coil unit 28, 30 in the direction of the contact area 34.

[0113] In particular, the length of the boom 62 is adjustable, for example by means of a motor and a rack and pinion drive.

[0114] The damping device 48 is in the Figures 8 and 9 The image is shown enlarged. The damping device 48 has a support frame 64 and a damping roller 66.

[0115] The support frame 64 has two supports 68, which are arranged on opposite sides of the two electrodes 24, 26. In other words, the two electrodes 24, 26 run between the two supports 68.

[0116] The damping roller 66 is arranged above, i.e., on the side of the electrodes 24, 26 facing away from the cooling roller 20. The damping roller 66 is rotatably mounted on the support frame 64 about an axis of rotation R1, the axis of rotation R1 being perpendicular to the longitudinal direction of the electrodes 24, 26 and perpendicular to the direction of the width of the electrodes 24, 26.

[0117] The damping roller 66 rests on the upper edges of the two electrodes 24, 26, i.e., the edges facing away from the cooling roller 20. It therefore rotates with the movement of the first electrode 24 during winding and unwinding.

[0118] In the direction of the width of the electrodes 24, 26, the damping roller 66 is movably mounted, for example by spring action.

[0119] During operation of the stretching machine 10, a high-voltage electric field is generated between the electrodes 24, 26 and the cooling roller 20 by means of the application device 22, in particular the two parallel, band-shaped electrodes 24, 26, which are subjected to high voltage. The film 16 passes through the electric field due to the rotational movement of the cooling roller 20.

[0120] The electric field electrically charges the surface of the cooling roller 20, causing the polar molecules of the film 16's plastic material to align. This creates an electrostatic attraction between the cooling roller 20 and the film 16. This attraction causes the film 16 to be pressed evenly against the cooling roller 20.

[0121] During operation, the first electrode 24 (and, if appropriate rotatable coils 38 are provided, also the second electrode 26) is continuously moved along its longitudinal direction, i.e., unwound in the first coil unit 28 and wound in the second coil unit 30, or vice versa. In this way, deposits caused by evaporation of the plastic material of the film 16 are removed, thereby increasing the homogeneity of the electric field.

[0122] Deposits are further reduced by the low voltage applied to electrodes 24 and 26. This low voltage generates a current, also called heating current, through each of the electrodes 24 and 26 from the first coil unit 28 to the second coil unit 30 (or vice versa) with a current intensity between 1 A and 8 A.

[0123] For example, the current through an electrode 24, 26 designed as a 3 mm strip is between 2 and 2.5 A, and through an electrode 24, 26 designed as a 12.7 mm strip it is about 7 A. When using a wire as electrode 26, the currents are lower.

[0124] Electrodes 24, 26 are not grounded, so a crack in electrode 24, 26 results in an interruption of the current.

[0125] The current heats up the electrodes 24, 26, which means that the evaporations of the plastic material of the film 16 are less likely to condense on the electrodes 24, 26.

[0126] Despite the mechanical stress applied to the electrodes 24, 26 by the rotatable coils 38 or the clamping device 44, the electrodes 24, 26 can oscillate, for example, with an amplitude perpendicular to the side surfaces, in the direction of the width of the electrodes 24, 26, and / or about the longitudinal axis of the electrodes 24, 26. The damping device 48 dampens or prevents these oscillations of the electrodes 24, 26, so that the electric field remains constant. This further improves the quality of the contact.

[0127] It is also conceivable that vibrations are prevented by a wave-like pattern of the electrodes 24, 26 in the contact area 34. For this purpose, the contact device 22 then has a bracket with pins around which the electrodes 24, 26 are guided.

[0128] The use of the two ribbon-shaped electrodes 24, 26 results in the maximum electric field on the foil surface at the point of first contact with the cooling roller 20. In this way, the high voltage can be reduced without compromising the quality of the application, thereby reducing spark discharges.

[0129] In the Figures 10 and 11 A second embodiment of the cooling roller unit 12 or positioning device 22 according to the invention is shown. This corresponds essentially to the first embodiment, so only the differences will be discussed below. Identical and functionally equivalent parts are provided with the same reference numerals.

[0130] The Figures 10 and 11 show a damping device 48 of a second embodiment of the attachment device 22.

[0131] In this second embodiment, the damping device 48 has two damping rollers 66, each of which is attached to a bearing block 70.

[0132] Each bearing block 70 is resiliently mounted perpendicular to the side surfaces of the electrodes 24, 26, so that the damping rollers 66 are also resiliently mounted.

[0133] Each of the damping rollers 66 is rotatable about a rotation axis R2, which is perpendicular to the longitudinal direction and parallel to the direction of the width of the electrodes 24, 26. In other words, the rotation axis R2 extends parallel to the side surfaces but perpendicular to the longitudinal direction of the electrodes 24, 26.

[0134] The two electrodes 24, 26 are guided between the two damping rollers 66, with each damping roller 66 contacting the side surface of one of the electrodes 24, 26. The two electrodes 24, 26 do not, in particular, touch each other.

[0135] In other words, each damping roller 66 is assigned one of the electrodes 24 or 26, which runs on its side surface.

[0136] It is also conceivable that, in addition to the two damping rollers 66 of the second embodiment, a damping roller 66 as shown in the first embodiment is also present in order to further increase the damping effect.

[0137] In the Figures 12 to 14 Further embodiments of the positioning device 22 are shown, which essentially correspond to the first embodiment. Therefore, only the differences will be discussed below, and identical and functionally equivalent parts are designated with the same reference numerals. They may also exhibit the features of the second embodiment.

[0138] In Figure 12 is a third embodiment of the positioning device 22 in a section similar to that of the Figure 3 depicted.

[0139] In this embodiment, the ribbon-shaped electrodes 24, 26 do not have the same width, but rather different widths.

[0140] In the illustrated embodiment, the first electrode 24 has a smaller width than the second electrode 26. It is also conceivable that the second electrode 26 has a smaller width than the first electrode 24.

[0141] Furthermore, the second electrode 26 is offset from the first electrode 24 in the direction of its width. In this way, the electric field can be adapted to the specific conditions of the application device 22 or the cooling roller unit 12, for example the slot die 18.

[0142] It is also conceivable that the application device 22 has three or more band-shaped electrodes that run parallel in the application area 34. One, several, or all of these electrodes can be movable in their longitudinal direction.

[0143] In Figure 13is a fourth embodiment of the positioning device 22 in a section similar to that of the Figure 3 depicted.

[0144] In this fourth embodiment, the second electrode 26 is not ribbon-shaped, but wire-like, in particular designed as a wire. Virtually any other cross-section of the second electrode 26 is also conceivable.

[0145] In the fourth embodiment, the second electrode 26 runs at the same distance to the cooling roller 20 as the first electrode 24, more precisely the edge of the first electrode 24 facing the cooling roller 20.

[0146] However, it is also conceivable that the second electrode 26 is arranged further away from the cooling roller 20.

[0147] In Figure 14 is a fifth embodiment of the positioning device 22 in a section similar to that of the Figure 3 depicted.

[0148] In this fifth embodiment, the application device 22 has a third electrode 72 in addition to the first electrode 24 and the second electrode 26. The application device 22 of the fifth embodiment thus has three electrodes 24, 26, 72.

[0149] The first electrode 24 is ribbon-shaped. The second electrode 26 and the third electrode 72 are designed as wire-like components, in particular as wires. Virtually any other cross-section for the second electrode 26 and / or the third electrode 72 is also conceivable.

[0150] The second and third electrodes 26, 72 are arranged on opposite sides of the first electrode 24. The second and third electrodes 26, 72 can be equidistant from the first electrode 24.

[0151] In the example shown, however, the first electrode 24 is not directly between the second and third electrodes 26, 72, i.e. the first electrode 24 does not intersect an imaginary connecting line between the second electrode 26 and the third electrode 72.

[0152] The first electrode 24 is offset from the second and third electrodes 26, 72 towards the cooling roller 20.

[0153] The second and third electrodes 26, 72 can be the same distance from the cooling roller 20.

[0154] The different arrangements and designs of the electrodes 24, 26, 72 allow the electric field to be appropriately configured for the respective application, in particular for the plastic material used.

[0155] It is also conceivable that the second electrode 26 and / or the third electrode 72 are ribbon-shaped.

[0156] Likewise, each of the three electrodes 24, 26, 72 can be subjected to high voltage and / or low voltage, and can be either movable in the longitudinal direction or statically designed.

Claims

1. Application device for the electrostatic application of a film (16) on a chill roll (20), having a first coil unit (28), a second coil unit (30), an application area (34) that is situated between the coil units (28, 30), a high-voltage source (32) as well as at least two electrodes (24, 26), wherein at least the first electrode (24) of the at least two electrodes (24, 26) is ribbon-shaped, wherein the electrodes (24, 26) run from the first coil unit (28) to the second coil unit (30) in the application area (34), and wherein a high voltage is applied to both the electrodes (24, 26) by the high-voltage source (32), wherein one, several or all of the electrodes (24, 26, 72) are moveable between the first coil unit (28) and the second coil unit (30) in their longitudinal direction.

2. Application device according to Claim 1, characterised in that the second electrode (26) of the at least two electrodes (24, 26) is ribbon-shaped or wire-like, in particular is a wire.

3. Application device according to Claim 1 or 2, characterised in that a third electrode (72) is provided, wherein the third electrode (72) is ribbon-shaped or wire-like, in particular is a wire.

4. Application device according to one of the preceding claims, characterised in that the electrodes (24, 26, 72) run parallel to each other and / or each have two lateral surfaces, wherein the electrodes (24, 26, 72) each face each other with one of their lateral surfaces.

5. Application device according to one of the preceding claims, characterised in that the electrodes (24, 26, 72) in the application area (34) have a spacing of 3 mm to 15 mm, in particular of 5 mm to 10 mm, from each other.

6. Application device according to one of the preceding claims, characterised in that the electrodes (24, 26, 72) have the same width or different widths and / or in that the width of the electrodes (24, 26, 72) is between 3 mm and 15 mm, in particular greater than or equal to 4 mm and less than 13 mm, and / or characterised in that the electrodes (24, 26, 72) are arranged offset or flush in their width direction.

7. Application device according to one of the preceding claims, characterised in that in the first and in the second coil unit (28, 30) at least one rotatable coil (38) is provided onto which the one, several or all of the electrodes (24, 26, 72) are partially wound.

8. Application device according to one of the preceding claims, characterised in that in at least one of the coil units (28, 30), in particular in both coil units (28, 30), a voltage supply unit (40) is provided, which electrically connects the electrodes (24, 26, 72) to the at least one high-voltage source (32), in particular wherein the voltage supply unit (40) has a roll (52) on which the first electrode (24) is guided, and / or wherein the voltage supply unit (40) has an arched course (54) along which the second electrode (26) and / or the third electrode (72) is guided.

9. Application device according to one of the preceding claims, characterised in that the first coil unit (28) and / or the second coil unit (30) has a damping device (48), which is configured to damp vibrations from the electrodes (24, 26) in the application area (34).

10. Application device according to Claim 9, characterised in that the damping device (48) has a damping roll (66) of which the rotational axis (R1) is perpendicular to the longitudinal direction and perpendicular to the width direction of the electrodes (24, 26), wherein the damping roll (66) is mounted so that it can be moved in the width direction and rests on an edge of each of the electrodes (24, 26, 72), in particular on the edge facing away from chill roll, in particular wherein the damping device (48) has two damping rolls (66) of which the rotational axes (R2) are perpendicular to the longitudinal direction and parallel to the width direction of the electrodes (24, 26), wherein each of the electrodes (24, 26, 72) touches one of the damping devices (66).

11. Application device according to one of the preceding claims, characterised in that the application device (22) has several insulation devices (50), in particular insulating conduits, insulation grommets and / or insulating sleeves, which extend from the corresponding coil unit (28, 30) to the application area (34), wherein the electrodes (24, 26, 72) run through the insulation devices (50), in particular wherein at least one of the insulation devices (50) is provided for each of the electrodes (24, 26, 72) on each of the coil units (28, 30).

12. Application device according to Claim 11, characterised in that the insulation devices (50) are affixed to the damping device (48) in a vibration-damping manner.

13. Application device according to one of the preceding claims, characterised in that a low voltage is applied to at least one of the electrodes (24, 26, 72), in particular in addition to the high voltage.

14. Casting unit having a slot die (18), a chill roll (20) and an application device (22) according to one of the preceding claims, in particular wherein the chill roll (20) is earthed.

15. Stretching system for producing a film, in particular a transverse, longitudinal and / or simultaneous stretching system, having a furnace (14) and a casting unit (12) according to Claim 14.