Feeding device, cooling roller device, and thin film drawing device

Abstract

To provide a feeding device which can reduce spark discharge generated between an electrode and a cooling roller, a cooling roller device, and a thin film drawing device.SOLUTION: A feeding device (22) which bonds a thin film (16) to a cooling roller (20) by static electricity is assembled with a first winder (28), a second winder (30), a bond region (34) arranged between the first winder (28) and the second winding device (30), a high voltage source (32), and at least two electrodes (24,26), wherein at least the first electrode (24) of at least two electrodes (24,26) is belt-shaped. Two electrodes (24,26) subjected to high voltage from the high voltage source (32) are arranged in the bond region from the first winder (28) to the second winder (30). The feeding device (22) is provided in a cooling roller device (12) and a drawing device.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a feeder for electrostatically attaching a thin film to a cooling roller, a cooling roller device, and a thin film stretching device including the cooling roller device. [Background technology]

[0002] When manufacturing a thin resin film (plastic film), the molten resin for manufacturing the thin film is first supplied onto a cooling roller, and the molten resin is cooled and solidified on the cooling roller to form a thin film. However, it is necessary to attach the thin film to the cooling roller uniformly and continuously in the entire width and length directions of the thin film and to cool the molten resin uniformly in order to manufacture a thin film with uniform material properties.

[0003] A technology is known that uses multiple electrodes to generate a high-intensity electric field near the surface of a cooling roller through which the thin film passes, using a mechanical solution to prevent deformation and adhesion of the thin film. The surface of the cooling roller is charged, so the polar molecules of the thin film are oriented by the electric field. The Coulomb force (electrostatic attraction) generated between the thin film and the cooling roller causes the thin film to adhere uniformly to the cooling roller.

[0004] If a high voltage of 9 kV or more is applied between multiple electrodes to generate a high-intensity electric field, an undesirable spark discharge (explosive fire phenomenon) may occur between the multiple electrodes and the cooling roller, damaging the surface of the cooling roller and reducing the quality of the thin film produced. Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a supply device, a cooling roller device, and a thin film stretching apparatus that reduce spark discharge occurring between an electrode and a cooling roller. [Means for solving the problem]

[0006] The object of the present invention is achieved by a supply device that includes a first winder, a second winder, an attachment region between the first winder and the second winder, a high voltage source, and at least two electrodes, and that forms at least a first electrode of the at least two electrodes into a band shape to attach a thin film to a cooling roller using static electricity. The at least two electrodes to which a high voltage is applied from the high voltage source are disposed in the attachment region from the first winder to the second winder.

[0007] By using a pair of strip electrodes to which a high voltage is applied, multiple homogeneous electric fields with high electric field strength, especially maximum electric field strength, are generated at the contact area between the cooling roller and the thin film. Compared to other solutions, the high voltage that generates multiple electric fields of the same strength due to electric field concentration is reduced. The high voltage between the multiple electrodes is reduced, reduced, or completely avoided.

[0008] The high voltage applied to the strip electrodes is, for example, 5 kV to 10 kV, particularly 7 kV to 9 kV, and may reach 20 kV.

[0009] In an embodiment of the invention, the second of the at least two electrodes is formed in strip or wire shape, in particular in wire, to improve the homogeneity of the electric field intensity.

[0010] In another embodiment of the invention, the homogeneous field strength is further improved by a third electrode which is formed in strip or wire shape, in particular in wire shape.

[0011] For example, with multiple electrodes arranged parallel to each other, the electric field strength is highly homogenized.

[0012] The pair of side surfaces provided on each of the two electrodes facing each other further improves the uniformity of the electric field intensity.

[0013] It is preferable to arrange the sides of the electrodes parallel to each other.

[0014] In another embodiment of the invention, the electrodes are spaced apart from one another in the attachment area by a distance of 3 mm to 15 mm, in particular 5 mm to 10 mm, to achieve a particularly good electric field concentration.

[0015] For example, electrodes may have the same width to further improve uniformity of the electric field strength, but different widths may also affect multiple maximum electric field strength conditions.

[0016] By setting the width of the electrodes to 3 mm to 15 mm, particularly 4 mm or more and less than 13 mm, a very homogeneous electric field can be ensured.

[0017] The electrodes can be arranged in a widthwise offset or coplanar arrangement to suit the needs of the cooling roller apparatus.

[0018] For example, the width direction corresponds to the radial direction of the roller.

[0019] In certain embodiments of the present invention, one, more or all of the multiple electrodes are longitudinally movably disposed between the first and second winders, and in particular, at least one rotatable reel is provided for partially winding one, more or all of the multiple electrodes within the first and second winders to remove deposits that adversely affect the electric field quality on one, more or all of the electrodes.

[0020] For example, a plurality of electrodes are partially wound on a rotatable spool provided on each of a plurality of winders.

[0021] In particular, at least one of the rotatable winding forms is driven.

[0022] In an embodiment of the invention, one of the electrodes, in particular the second electrode or electrodes, is stationary and one of the stationary electrodes is fixed to a tensioning device provided on the second winder or at a fixed position on the first winder, thus allowing a good attachment of the electrodes to the supply device.

[0023] In an embodiment of the present invention, at least one of the multiple winders, particularly both winders, is provided with a voltage supply device, which electrically connects the electrodes to at least one high voltage source, thereby ensuring that a high voltage is applied to the multiple electrodes.

[0024] For example, a common high voltage supply may be provided for both winders or a separate high voltage supply may be connected to each winder.

[0025] The voltage supply device of an embodiment of the present invention has a roller that guides the first electrode and / or an arc portion provided on the voltage supply device that contacts multiple electrodes and guides the second electrode and / or the third electrode in a highly reliable and space-saving manner.

[0026] For example, the outer surface of the arcuate portion of the voltage supply device is formed into a circular segment.

[0027] A damping device provided on the second winder damps vibrations of the electrode in the attachment area to prevent harmful vibrations of the electrode.

[0028] For example, an electrode wound on a winder may be routed from a number of damping devices to an attachment region.

[0029] The vibrations to be damped are in particular those having an amplitude in the width direction of the electrode perpendicular to the side surfaces of the electrode and / or torsional vibrations about the longitudinal axis of the electrode.

[0030] For example, a damping roller having a rotation axis perpendicular to both the longitudinal direction and the width direction of the electrode is provided in the damping device, the damping roller is supported so as to be movable in the width direction, and abuts against each outer edge of the electrode, particularly the outer edge opposite the cooling roller, thereby realizing a damping device using only a single damping roller.

[0031] The damping device alternatively or additionally has two damping rollers, the rotation axes of which are perpendicular to the longitudinal direction of the electrodes and parallel to the width direction, and each electrode abuts one of the damping rollers, so that the vibrations occurring in each electrode are damped individually, and the electrodes do not affect each other.

[0032] The damping rollers are in particular in contact with the side surfaces of the electrodes.

[0033] For example, both electrodes are disposed between and penetrating both damping rollers.

[0034] The feeding device according to the embodiment of the invention comprises a number of insulating devices, in particular a number of insulating tubes, a number of insulating ridges and / or a number of insulating sleeves, arranged from the corresponding winders towards the application area, the electrodes being arranged in the number of insulating devices, in particular at least one of the number of insulating devices being provided for each of the number of electrodes at each of the number of winders, the insulating devices ensuring that spark discharges outside the application area are prevented.

[0035] For example, the isolator may be constructed from polyetheretherketone (PEEK), specifically polyetheretherketone that is annealed.

[0036] The insulating device surrounds the electrode at least at its outer edge in the direction of the cooling roller.

[0037] In an embodiment of the invention, an isolating device which is vibration-dampingly fixed to the damping device limits vibrations of the guided electrode to a minimum.

[0038] In an embodiment of the present invention, a low voltage is applied to at least one of the electrodes, particularly in addition to the application of a high voltage, and even if the electrode to which the low voltage is applied is heated, the amount of deposits or condensation in contact with the electrode is reduced, since the deposits or condensation form mainly on the cooler surface.

[0039] For example, a current is formed between the two winders through each electrode to which a low voltage is applied, and if a crack occurs, especially in the electrode that is not grounded, the current stops.

[0040] For example, the low voltage is a maximum of 150 V, for example, 60 V to 130 V, particularly 120 V. The amount of current generated by application of the low voltage is 1 A to 8 A.

[0041] For the purpose of applying the low voltage, for example, the supply device comprises a low voltage power supply. The high voltage power supply and the low voltage power supply can be implemented in a single device.

[0042] The object of the present invention is also achieved by a cooling roller device comprising at least an extrusion die, a cooling roller (also called a "casting device"), and the supply device, in particular a cooling roller device comprising a grounded cooling roller.

[0043] With a high voltage applied and a grounded cooling roller, a small current called the pinning current is created.

[0044] The amount of current at a high voltage of 20 kV is, for example, in the range of 25 mA to 30 mA. At a high voltage of 9 kV, a current of about 9 mA to 12 mA is generated.

[0045] When a crack forms in the electrode, the high voltage source is turned off, and the crack in the electrode can be detected by detecting the pulse edge waveform when the high voltage source is turned off.

[0046] The advantages and features described above with respect to the supplying apparatus equally apply to the cooling roller apparatus, and vice versa.

[0047] The distance from the electrode to the cooling roller is at least the thickness of the film, for example at least 2 mm and / or at most 20 mm.

[0048] The object of the present invention can also be achieved by a thin film stretching apparatus, particularly a transverse stretching apparatus, a longitudinal stretching apparatus and / or a simultaneous stretching apparatus, which is provided with a heating furnace and a cooling roller device and produces a thin film.

[0049] The advantages and features described above with respect to the feeding system and / or the cooling system are equally applicable to the thin film stretching system and vice versa.

[0050] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which: [Brief description of the drawings]

[0051] [Figure 1] FIG. 1 is a schematic plan view of a thin film stretching apparatus of the present invention equipped with a cooling roller device of the present invention. [Diagram 2] FIG. 2 is a schematic perspective view of the cooling roller device of FIG. 1 equipped with a supply device of the present invention; [Diagram 3] 1 is a schematic cross-sectional view of an operating cooling roller device; [Figure 4] FIG. 3 is a perspective view of one winder provided in the supply device shown in FIG. [Diagram 5] FIG. 1 is a schematic plan view showing components provided on a second winder and a first winder of a supply device and the arrangement of electrodes in the corresponding winders; [Figure 6] FIG. 1 is a schematic plan view showing components provided on a second winder and a first winder of a supply device and the arrangement of electrodes in the corresponding winders; [Figure 7] FIG. 5 is a perspective view of an electrode protruding from an insulating device of the winder of FIG. [Figure 8] FIG. 5 is a perspective view of a damping device provided in the winder of FIG. [Figure 9] FIG. 9 is a perspective view showing a cross section of the damping device of FIG. 8; [Figure 10] FIG. 2 is a perspective view showing a second embodiment of a damping device for a winder; [Figure 11] FIG. 11 is a partially open perspective view of a damping device different from that of FIG. [Figure 12] FIG. 13 is a schematic cross-sectional view of a third embodiment of a supply device in operation; [Figure 13] FIG. 13 is a schematic cross-sectional view of a fourth embodiment of a supply device in operation; [Figure 14] FIG. 5 is a schematic cross-sectional view of a fifth embodiment of a supply device in operation; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] 1 shows a thin film stretching apparatus 10 of the present invention for producing a thin film, comprising a cooling roller unit 12 (also called a "casting unit") and a heating furnace 14. For example, a transverse stretching unit, a longitudinal stretching unit and / or a simultaneous stretching unit can be used as the thin film stretching apparatus 10.

[0053] In this embodiment, the cooling roller device 12 first feeds the thin film 16 (also called the "cast thin film") to be produced into the furnace 14 to produce a thin film to be further stretched. The thin film 16 in the furnace 14 is stretched in the machine direction and / or the cross direction by known means to produce a uniaxially or biaxially oriented thin film.

[0054] FIG. 2 is an enlarged schematic perspective view of the cooling roller device 12. As shown in FIG.

[0055] The cooling roller device 12 includes an extrusion die 18 that continuously extrudes molten resin, a cooling roll 20 to which the molten resin extruded from the extrusion die 18 is continuously supplied, and a supply device 22 that attaches the molten resin to the cooling roll 20 by electrostatic attraction.

[0056] The cooling roll 20 that cools the molten resin is also called a cooling roller or a "chill roller."

[0057] An extrusion die 18 disposed above the chill roll 20 continuously supplies molten resin onto the chill roll 20, and the molten resin supplied onto the chill roll 20 is formed into a thin film 16. In particular, polyethylene terephthalate (PET) is used to form the thin film 16 by the chill roll 20, but the thin film 16 is not limited to this resin.

[0058] The molten resin uniformly supplied onto the chill roll 20 by the supply device 22 is formed into a thin film 16. The chill roll 20 in Fig. 2 is rotated in a counterclockwise direction. In the illustrated example, the thin film 16 formed when the chill roll 20 has rotated about 3 / 4 of the total rotation angle is finally peeled off from the chill roll 20, further cooled as necessary, and supplied to the heating furnace 14.

[0059] The electrostatic supply device 22 has two strip-shaped electrodes, a first electrode 24 and a second electrode 26, two winders, a first winder 28 and a second winder 30, a low voltage source 31, and a high voltage source 32.

[0060] In the illustrated embodiment, the low voltage source 31 and the high voltage source 32 are formed as a single power supply device. Alternatively, the low voltage source 31 and the high voltage source 32 may be configured as separate power supplies.

[0061] The winders 28, 30 are disposed in the axial direction of the chill roll 20 and in front of and behind the chill roll 20. An adhesion region 34 formed between the winders 28, 30 where the molten resin is supplied to and adheres to the chill roll 20 also includes the region of the thin film 16 on the chill roll 20 as viewed in the axial direction of the chill roll 20.

[0062] A pair of strip-shaped electrodes 24, 26 are supported between a pair of winders 28, 30 and are stretched between the winders 28, 30, passing through an attachment region 34.

[0063] 3 is an end view of the cooling roller device 12 as viewed in the axial direction of the cooling roll 20. Only the two electrodes 24, 26 of the supply device 22 are shown in a simplified manner.

[0064] 3, each of the electrodes 24, 26 of the supply device 22 is formed in a strip shape having a width much longer than its thickness, particularly an order of magnitude longer than its thickness. Also, the longitudinal dimension of each of the electrodes 24, 26 is several orders of magnitude larger than its width.

[0065] Each of the electrodes 24, 26 has two side surfaces defined by the longitudinal and widthwise dimensions of the electrodes 24, 26, and two outer edges of the two side surfaces. One of the outer edges of each electrode 24, 26 is disposed in the direction of the cooling roll 20, and the other of the outer edges of each electrode 24, 26 is disposed in the opposite direction to the cooling roll 20. The direction between the outer edges of the same electrode 24, 26 is referred to as the width direction of the electrodes 24, 26.

[0066] In the first embodiment, both electrodes 24, 26 have the same width, for example, 3 mm to 15 mm, particularly 4 mm to 13 mm. For example, the width of 12.7 mm is given to both electrodes 24, 26.

[0067] In the illustrated embodiment, one side of each electrode 24, 26 faces the other electrode 26, 24. The electrodes 24, 26 are disposed parallel to each other at least in the attachment region 3.

[0068] The electrodes 24, 26 are spaced apart from each other in the attachment area 34 by a distance of 3 mm to 15 mm, in particular 5 mm to 10 mm.

[0069] Both electrodes 24, 26 are disposed on the same parallel plane in the width direction, and a line connecting the outer edges of both electrodes 24, 26 is perpendicular to the side surface.

[0070] In particular, the width direction of one of the electrodes 24 , 26 is aligned with the radial direction of the chill roll 20 .

[0071] Both electrodes 24, 26 are disposed downstream of the extrusion die 18 in the rotation direction of the chill roll 20. For example, both electrodes 24, 26 are separated from the chill roll 20 by at least the thickness of the thin film 16, for example, a distance of at least 2 mm. The distance between both electrodes 24, 26 and the chill roll 20 is at most 20 mm.

[0072] High voltage power supplied from a high voltage generation source 32 is applied to both electrodes 24, 26. The high voltage is, for example, 5 kV to 10 kV, particularly 7 kV to 9 kV.

[0073] A strong electric field is generated in the adhesion region 34 between the grounded chill roll 20 and the electrodes 24, 26, and the thin film 16 is guided through the region of strong electric field.

[0074] A small current called pinning current is also formed. For example, at a high voltage of 20 kV, the pinning current is about 30 mA. At a high voltage of 9 kV, a pinning current of about 12 mA can occur.

[0075] The high voltage source is switched off when a crack occurs in one of the electrodes 24, 26. When a crack occurs in one of the electrodes 24, 26, a pulse signal edge generated at the time of the crack occurrence can be detected by the high voltage source.

[0076] A low voltage of, for example, less than 150 V, particularly 60 V to 130 V, for example 120 V, is also applied to at least one or both of the electrodes 24, 26 from a low voltage source 31. The high voltage source 32 and the low voltage source 31 are suitably connected in series.

[0077] 4 shows a perspective view of the second winder 30 in an open state. The second winder 30 is disposed to the left of the chill roll 20 in FIG.

[0078] The first winder 28, which is disposed to the right of the cooling roll 20, has the same configuration as the second winder 30, but is disposed in a mirror symmetrical manner. Differences between the first winder 28 and the second winder 30 are shown individually.

[0079] The second winder 30 is provided with a housing 36, a rotatable reel 38, a voltage supply device 40, a first deflection roller 42, a tensioning device 44, a second deflection roller 46, a damping device 48 and two insulating devices 50.

[0080] 5 shows a simplified version of the winder 30, showing only the electrodes 24, 26 and the components that guide the electrodes 24, 26. For example, the housing 36, the damping device 48, and the insulating device 50 are not shown.

[0081] The strip-shaped first electrode 24 stretched between a rotatable former 38 and a voltage supply 40 is partially wound on the rotatable former 38 .

[0082] A voltage supply device 40 electrically connected to the high voltage source 32 has a deflecting roller 52 and an arcuate portion 54 .

[0083] When the movement of the strip-shaped first electrode 24 is guided by the deflecting roller 52 , a high voltage supplied from the high voltage source 32 is applied to the first electrode 24 .

[0084] From the turning roller 52 the first electrode 24 moves to the first turning roller 42 , leaves the winder 30 and moves to the deposition area 34 .

[0085] A tensioning bolt 56 is provided on the tensioning device 44 of the second winder 30 operated by a motor 58 (FIG. 4), and an end of the strip-shaped second electrode 26 is fixed to the tensioning bolt 56 .

[0086] The belt-shaped second electrode 26 arranged on the voltage supply device 40 changes direction along a circular arc portion 54 provided on the voltage supply device 40 .

[0087] The arcuate portion 54 has an arcuate outer surface that guides the movement of the second electrode 26. For example, the arcuate outer surface is formed into a segment of a circle.

[0088] A high voltage is applied from a high voltage source 32 to the band-shaped second electrode 26 in contact with the arc portion 54 .

[0089] The strip-shaped second electrode 26 wound around the second turning roller 46 is arranged parallel to the strip-shaped first electrode 24 due to the direction change at the second turning roller 46. Then, both electrodes 24, 26 pass from the second winder 30 through the attachment area 34 and are finally introduced into the first winder 28, which is shown in a simplified form in FIG.

[0090] In the reverse order to that described for the second winder 30, the strip-shaped first electrode 24 moves through the first deflection roller 42 and the deflection roller 52 of the voltage supply device 40 and is finally wound onto the rotatable reel 38.

[0091] The voltage supply 40 of the first winder 28 is also electrically connected to the high voltage source 32, although separate high voltage sources may be provided for the multiple winders 28, 30.

[0092] The rotatable reels 38 of both the first winder 28 and the second winder 30 can be driven to move the first electrode 24 between the first winder 28 and the second winder 30. For example, the first electrode 24 can be released from the rotatable reel 38 of the first winder 28 and introduced into the second winder 30 through the attachment area 34, and the first electrode 24 can be wound onto the rotatable reel 38 of the second winder 30.

[0093] Furthermore, the tension or internal stress of the strip-shaped first electrode 24 can be set by the torque of the spool 38 which is rotated.

[0094] In the embodiment shown, in contrast to the first electrode 24, the strip-shaped second electrode 26 is held stationary. The second electrode 26 is arranged in a first winder 28 and is led to a voltage supply device 40 from a second deflection roller 46. Furthermore, the second electrode 26 is fixed by an end piece 60 in the first winder 28. In contrast to the second winder 30, the first winder 28 is not provided with a tensioning device 44.

[0095] The tension or mechanical stress of the second electrode 26 is set by a tensioning device 44 .

[0096] Instead of the end piece 60 and tensioning device 44, a plurality of rotatable reels 38 may be provided for the second electrode 26, similar to the plurality of rotatable reels 38 for the first electrode 24, so that the second electrode 26 is also configured to be movable.

[0097] For example, a rotatable former for each electrode 24,26 may be provided within each winder 28,30.

[0098] It is also contemplated that multiple electrodes 24, 26 may be wound on the same rotatable reel 38. For example, a common rotatable reel 38 may be provided with different regions for the different electrodes 24, 26, so that the mechanical tension of the different electrodes 24, 26 can be set individually by a tensioning device.

[0099] The electrodes 24,26 shown in FIG. 4 are passed from the winders 28,30 through the damping devices 48 and finally through the insulating devices 50 before being released from the winders 28,30.

[0100] The arrangement of multiple isolation devices 50 beginning with dampening device 48 and extending to attachment area 34 can also be seen in FIG.

[0101] A plurality of insulating devices 50 are provided along the uncoated areas of the thin film 16 of the chill roll 20 .

[0102] 7 shows a perspective view of the end of the insulating devices 50 facing the attachment area 34. The electrodes 24, 26 in FIG.

[0103] The insulating devices 50 are, for example, insulating tubes, insulating grommets, and / or insulating cylinders having an elongated cross section of a substantially rectangular shape, for example, with rounded corners or arc-shaped short sides.

[0104] The inner longitudinal diameter of the insulating devices 50 corresponds to the width of the electrodes 24,26 so that a single electrode 24,26 is guided within one of the insulating devices 50.

[0105] Each of the plurality of isolation devices 50 in the illustrated embodiment completely encloses the electrode 24, 26 it contains from the surrounding environment.

[0106] However, configurations in which the insulating devices 50 surround, but do not completely surround, the electrodes 24, 26 relative to each other and / or towards the chill roll 20 are also contemplated.

[0107] The isolators 50 are made of an annealed resin, in particular polyetheretherketone (PEEK), which has proven to be particularly durable.

[0108] The plurality of isolators 50 are secured to the outlets of the plurality of dampening devices 48 by fasteners 74 shown in FIG.

[0109] The fixing device 74 has a number of vibration damping members 76, which constitute a number of dampers made of, for example, an elastic material, and the isolator 50 is tensioned between the vibration damping members 76. The tensioning structure may be attached, for example, by means of screws.

[0110] A plurality of dampening devices 48 may be provided on an arm 62 disposed from the housing 36 of each winder 28,30 to the attachment area 34.

[0111] For example, the length of the arm 62 can be adjusted by an electric motor and a rack and pinion gear.

[0112] 8 and 9 show enlarged perspective views of the damping device 48 having a support frame 64 and damping rollers 66. FIG.

[0113] The support frame 64 has two support posts 68 arranged opposite the surfaces of the electrodes 24, 26, and the electrodes 24, 26 pass through between the support posts 68.

[0114] The damping roller 66 is disposed above both electrodes 24, 26 in the opposite direction to the cooling roll 20. The damping roller 66 is supported by the support frame 64 to be rotatable about a rotation axis R1 that is perpendicular to the longitudinal direction of the electrodes 24, 26 and perpendicular to the width direction of the electrodes 24, 26.

[0115] A damping roller 66 disposed on the upper outer edges of both electrodes 24, 26 on the side opposite to the cooling roll 20 rotates in association with the movement of the first electrode 24 when the reel 38 is wound up or unwound.

[0116] For example, a spring-loaded damping roller 66 is journalled so as to be movable across the width of both electrodes 24,26.

[0117] During operation of the thin film stretching apparatus 10, when a high voltage is applied to the two strip-shaped electrodes 24, 26 arranged parallel to each other, a high-voltage electric field is generated between the chill roll 20 of the supply device 22 and the two electrodes 24, 26. During the rotational movement of the chill roll 20, the molten resin that is supplied from the extrusion die 18 onto the chill roll 20 to become the thin film 16 passes through the electric field region formed between the two electrodes 24, 26 and the chill roll 20.

[0118] The surface of the cooling roll 20 passing through the electric field region becomes charged, and the polar molecules of the resin material of the thin film 16 passing through the electric field region are oriented, so that the contact surface of the thin film 16 in contact with the cooling roll 20 adheres uniformly to the cooling roll 20 due to the electrostatic attraction generated between the cooling roll 20 and the thin film 16.

[0119] During the formation of the electric field region between the electrodes 24, 26 and the cooling roll 20, the first electrode 24 is unwound from the reel of the first winder 28, moves continuously in the longitudinal direction, and is wound up by the second winder 30 (the corresponding reel 38 may rotate, causing the second electrode 26 to also move continuously in the longitudinal direction), or conversely, the first electrode 24 unwound from the reel 38 of the second winder 30 may move continuously in the longitudinal direction and be wound up by the first winder 28. In this way, the deposits of the resin material of the thin film 16 are removed by evaporation, improving the uniformity of the electric field.

[0120] The deposits of resin material are also reduced by applying a low voltage to both electrodes 24, 26. The low voltage applied to both electrodes 24, 26 generates a current, which may be called a heating current, and the heating current of 1 A to 8 A flows through each of both electrodes 24, 26 from the first winder 28 to the second winder 30 (or in the opposite direction).

[0121] For example, the amount of current flowing through the strip electrodes 24, 26 having a width of 3 mm is 2 A to 2.5 A, and the amount of current flowing through the strip electrodes 24, 26 having a width of 12.7 mm is about 7 A. If a wire is used for the electrode 26, the amount of current is smaller.

[0122] If a crack occurs in one of the ungrounded electrodes 24, 26, the heating current is interrupted.

[0123] The amount of condensation of the evaporated resin material of the thin film 16 onto both electrodes 24, 26 heated by the heating current is reduced.

[0124] Whether or not mechanical tension is applied to the electrodes 24, 26, rotation of the reel 38 or actuation of the tensioning device 44 may induce vertical amplitude vibrations on the sides of the electrodes 24, 26, for example about the transverse and / or longitudinal axes of the electrodes 24, 26. The damping device 48 damps or prevents the vertical amplitude vibrations of the electrodes 24, 26 to maintain a constant electric field, further improving the adhesion of the thin film 16 to the chill roll 20.

[0125] It is also possible to consider a structure for suppressing wave-like vibration of both electrodes 24, 26 in the attachment region 34. When the supply device 22 guides the movement of both electrodes 24, 26, multiple protrusions of a support provided on the supply device 22 can suppress vibration of both electrodes 24, 26.

[0126] When using the strip electrodes 24, 26, the maximum electric field value occurs at the surface of the thin film that first contacts the chill roll 20, but the high voltage level can be reduced by electric field concentration and spark discharges can be suppressed without degrading the adhesion characteristics of the thin film to the chill roll 20.

[0127] The second embodiment of the cooling roller device 12 or the supply device 22 used in the present invention shown in Figures 10 and 11 is basically the same as the first embodiment, so in Figures 10 and 11, the same components in terms of structure and function are given the same reference numerals as in the previous drawings, and only the differences between the two will be described below.

[0128] 10 and 11 show a damping device 48 of a second embodiment of the feeder device 22.

[0129] The damping device 48 of the second embodiment has two damping rollers 66 each fixed to a single bearing base 70 .

[0130] Each bearing base 70 has a damping roller 66 journalled by a spring, and the bearing base 70 is provided in such a manner that the damping roller 66 is pressed perpendicularly against the side surfaces of both electrodes 24,26.

[0131] Each damping roller 66 rotates around a rotation axis R2 that is disposed perpendicular to the longitudinal direction and parallel to the width direction of the electrodes 24, 26. In other words, the rotation axis R2 is disposed parallel to the side surface of the damping roller 66 and perpendicular to the longitudinal direction of both electrodes 24, 26.

[0132] When the electrodes 24, 26 are guided between the damping rollers 66, one side of each of the electrodes 24, 26 contacts one of the damping rollers 66, but the electrodes 24, 26 do not contact each other.

[0133] In other words, each damping roller 66 assigned to one of the electrodes 24 or 26 is disposed opposite a side of the electrode 24 or 26 .

[0134] In addition to the two damping rollers 66 in the second embodiment, the damping rollers 66 in the first embodiment shown in Figs. 8 and 9 may be provided to improve the damping effect.

[0135] Figures 12 to 14 show a third embodiment having features of the second embodiment, but differing from the first embodiment shown in Figure 3 in terms of supply device 22. In Figures 12 to 14, the same reference numerals are used for structurally and functionally identical parts shown in Figure 3, and only the differences between the two embodiments will be described below.

[0136] FIG. 12 shows a cross-sectional view of a third embodiment of a supply device 22 similar to the first embodiment of FIG.

[0137] In the embodiment shown in FIG. 12, the widths of the strip electrodes 24, 26 are different and not identical.

[0138] The width of the first electrode 24 in the illustrated embodiment is smaller than the width of the second electrode 26. The width of the second electrode 26 may also be smaller than the width of the first electrode 24.

[0139] The second electrode 26 is offset widthwise relative to the first electrode 24. For example, the feed device 22, the chill roller device 12 or the electric field region can be adapted to the particular realities of the extrusion die 18.

[0140] The delivery device 22 may be provided with three or more strip electrodes arranged in parallel within the deposition area 34. Configurations may also be used that provide longitudinal movement for one, several or all of the electrodes provided.

[0141] FIG. 13 is a cross-sectional view similar to FIG. 3, showing a fourth embodiment of the supply device 22. As shown in FIG.

[0142] The second electrode 26 of the fourth embodiment is for example embodied as a wire-like, in particular non-strip-like conductor, The second electrode 26 may also be formed in any other cross-sectional shape.

[0143] For example, the second electrode 26 of the fourth embodiment can be positioned at the same distance between the outer edge of the first electrode 24 facing the chill roll 20 and the chill roll 20 .

[0144] A second electrode 26 may be positioned further away from the chill roll 20 .

[0145] FIG. 14 shows a cross-sectional view similar to FIG. 3 of a fifth embodiment of the supply device 22.

[0146] The supply device 22 of the fifth embodiment has three electrodes 24 , 26 , 72 including a third electrode 72 in addition to a first electrode 24 and a second electrode 26 .

[0147] The first electrode 24 is essentially strip-shaped. The second electrode 26 and the third electrode 72 are essentially wire-shaped, in particular embodied as conductors. The second electrode 26 and / or the third electrode 72 can also be formed in almost any other cross-sectional shape.

[0148] The second electrode 26 and the third electrode 72 are disposed on different sides of the first electrode 24. The second electrode 26 and the third electrode 72 can be disposed equidistant from the first electrode 24.

[0149] Unlike the illustrated example in which the first electrode 24 is positioned directly between the second electrode 26 and the third electrode 72, the first electrode 24 can be positioned without intersecting the imaginary line between the second electrode 26 and the third electrode 72.

[0150] The first electrode 24 can be positioned relative to the chill roll 20 offset from the second electrode 26 and the third electrode 72 .

[0151] The second electrode 26 and the third electrode 72 may be positioned equidistant from the chill roll 20 .

[0152] Different arrangements and configurations of electrodes 24, 26, 72 can produce electric field regions that are tailored to each application, particularly the conditions under which each resin material is used.

[0153] Strip-shaped second electrode 26 and / or third electrode 72 are also contemplated.

[0154] It is also possible to apply a high voltage and / or a low voltage to each of the three electrodes 24, 26, 72, and to provide the three electrodes 24, 26, 72 so that they are movable or stationary in the longitudinal direction.

Claims

1. A feeding device for electrostatically attaching a thin film (16) to a cooling roller (20) comprising a first winder (28), a second winder (30), an attachment area (34) provided between the first winder (28) and the second winder (30), a high voltage source (32), and at least two electrodes (24, 26), At least the first electrode (24) of the at least two electrodes (24, 26) is formed in a strip shape; The two electrodes (24, 26) are disposed in an attachment area (34) provided between the first winder (28) and the second winder (30); A supply device characterized in that a high voltage from a high voltage source (32) is applied to two electrodes (24, 26).

2. 2. A supply device according to claim 1, wherein at least the second electrode (26) of the two electrodes (24, 26) is formed in the shape of a strip or wire, in particular in the shape of a conductor.

3. 2. A supply device according to claim 1, comprising a third electrode (72) in the form of a strip or wire, in particular a conductor.

4. 2. The delivery device of claim 1, wherein the electrodes (24, 26, 72) are arranged parallel to one another and / or each have two sides, with each one of the sides of the electrodes (24, 26, 72) facing one another.

5. 2. A supply device according to claim 1, wherein the electrodes (24, 26, 72) are provided in the attachment area (34) at a distance of 3 mm to 15 mm, in particular 5 mm to 10 mm, from each other.

6. 2. The delivery device according to claim 1, wherein the electrodes (24, 26, 72) have the same or different widths and / or 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.

7. 2. The delivery device of claim 1, wherein the electrodes are arranged laterally offset or coplanar.

8. 2. The supply device of claim 1, wherein one, more than one or all of the plurality of electrodes (24, 26, 72) move longitudinally between the first winder (28) and the second winder (30), and in particular the first winder (28) and the second winder (30) are provided with at least one rotatable reel (38) for partially winding one, more than one or all of the plurality of electrodes (24, 26, 72).

9. 2. The supply device according to claim 1, wherein a voltage supply device (40) provided on at least one of the plurality of winders (28, 30), in particular on both winders (28, 30), electrically connects the plurality of electrodes (24, 26, 72) to at least one high voltage source (32).

10. 10. The supply device according to claim 9, wherein the voltage supply device (40) has a roller (52) for guiding the first electrode (24) and / or the second electrode (26) and / or the third electrode (72) are guided along an arc portion (54) provided on the voltage supply device (40).

11. 2. The feeding device of claim 1, wherein the damping device (48) provided on the first winder (28) and / or the second winder (30) damps vibrations of the plurality of electrodes (24, 26) in the attachment region (34).

12. 12. The supply device according to claim 11, wherein the rotation axis (R1) of the damping roller (66) provided in the damping device (48) is perpendicular to the longitudinal direction of the plurality of electrodes (24, 26) and perpendicular to the width direction of the plurality of electrodes (24, 26), and the damping roller (66) journaled so as to be movable in the width direction is arranged at each outer edge of the plurality of electrodes (24, 26, 72), in particular at the outer edge opposite to the cooling roller.

13. 13. The supply device according to claim 12, wherein the rotation axes (R2) of the two damping rollers (66) provided in the damping device (48) are perpendicular to the longitudinal direction of the plurality of electrodes (24, 26) and parallel to the width direction of the plurality of electrodes (24, 26), and each of the plurality of electrodes (24, 26, 72) abuts against one of the plurality of damping rollers (66).

14. the insulating devices (50) provided on the supply device (22), in particular insulating tubes, insulating rims and / or insulating sleeves, are arranged from the associated winders (28, 30) towards the application area (34); 2. The feeding device of claim 1, wherein the plurality of electrodes (24, 26, 72) are disposed within a plurality of insulating devices (50), and in particular, at least one of the plurality of insulating devices (50) contacts each of the plurality of winders (28, 30) for the plurality of electrodes (24, 26, 72).

15. 15. The feeding system of claim 14, wherein the plurality of isolators (50) are dampingly secured to the damping device (48).

16. 2. The delivery device of claim 1, wherein in addition to applying the high voltage, a low voltage is applied to at least one of the plurality of electrodes (24, 26, 72).

17. A cooling roller device comprising an extrusion die (18), a cooling roller (20), and the supply device (22) according to any one of claims 1 to 16, wherein the cooling roller (20) is grounded.

18. 18. A stretching apparatus, transverse stretching apparatus, longitudinal stretching apparatus and / or simultaneous stretching apparatus for producing a thin film, comprising a heating furnace (14) and a cooling roller device (12) according to claim 17.

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