Thin film pressing device, casting device, and thin film manufacturing device

Abstract

The present invention provides a thin-film pressing device that reduces sparks generated between the electrode and the cooling roll. [Solution] The thin film pressing device (32) for electrostatically attaching a thin film (F) to a cooling roll (28) comprises a first installation device (36), a second installation device (38), an installation area disposed between the first installation device (36) and the second installation device (38), a high voltage source (42), an electrode (34), at least one insulating device, and at least one vibration absorber (44). The electrode (34) extends from the first installation device (36) to the second installation device (38) in the installation area via at least one insulating device, and a high voltage is applied to the electrode (34) by the high voltage source (42). The vibration absorber (44) is attached to at least one insulating device and absorbs vibrations of the electrode (34), characterized in that the thin film pressing device is a thin film pressing device.

Description

Technical Field

[0001] The present invention relates to a thin film pressing device that attaches a thin film to a cooling roll by static electricity, a corresponding casting device, and a thin film manufacturing device that manufactures a thin film through the casting device.

Background Art

[0002] When manufacturing a thin resin film, first, molten resin is supplied to a cooling roll, and the molten resin is cooled and solidified to form a thin film. In order to cool the thin film uniformly and form uniform material properties, it is necessary to uniformly contact the thin film with the surface of the cooling roll over the entire width of the thin film and continuously contact the entire length of the thin film. A technique for avoiding deformation of the thin film by forming an intense electric field near the surface of the cooling roll through which the thin film passes using a plurality of electrodes and attaching the thin film to the cooling roll by a mechanical solution means is known. Due to the electric field, the polar molecules of the thin film are aligned, and an electrostatic attraction is formed between the thin film and the cooling roll, so the thin film is uniformly and automatically attracted to and adheres to the cooling roll.

Summary of the Invention

Problems to be Solved by the Invention

[0003] It is necessary to apply a high voltage of 8 kV or more than 8 kV between the electrode and the cooling roll to form an intense electric field between the electrode and the cooling roll. However, due to the high voltage between the electrodes, the surface of the cooling roll may be damaged by the sparks generated between the electrode and the cooling roll, and the quality of the manufactured thin film may deteriorate. Therefore, an object of the present invention is to provide a thin film pressing device, a casting device, and a thin film manufacturing device that reduce the sparks generated between the electrode and the cooling roll.

Means for Solving the Problems

[0004] The object of the present invention is solved by a thin film pressing device that adheres a thin film to a cooling roll by the action of electrostatics, the thin film pressing device comprising a first installation device, a second installation device, an installation area formed between the first and second installation devices, a high voltage source, electrodes, at least one insulating device, and at least one vibration absorber. The at least one insulating device extends into the thin film area between the associated pair of installation devices. The at least one electrode is attached to the installation area between the first and second installation devices via the at least one insulating device, and a high voltage from the high voltage source is applied to the electrode. The vibration absorber attached to the at least one insulating device absorbs vibrations of the electrode.

[0005] The vibrations of the insulating device and electrodes that constantly occur during the operation of the thin film pressing device are rapidly absorbed by the vibration absorber, so that the vibrations of the insulating device and electrodes are quickly dampened and have a small amplitude. This prevents the electrodes from approaching the cooling roll due to vibration, and substantially avoids electrode contact with and penetration into any portion of the molten resin flowing out of the nozzle of the slot mold. It also prevents large changes in the separation distance between the electrodes and the cooling roll, which would adversely affect the visual and / or quality characteristics of the thin film and affect the pressing force of the thin film against the cooling roll.

[0006] In embodiments of the present invention, a vibration absorber having a natural frequency corresponding to the electrode's natural frequency, particularly the lowest natural frequency of the electrode, effectively absorbs the electrode's vibrations. Furthermore, the vibration absorber has multiple natural frequencies, including one, a number of, or all of the natural frequencies corresponding to the electrode's natural frequency.

[0007] In this specification, the term "corresponding" should be understood to mean that the natural frequency of the vibration absorber is the same as the natural frequency of the electrode or falls within ±10% of the electrode's natural frequency. The vibration absorber of the embodiment of the present invention comprises a base, at least one vibration-absorbing mass, and at least one connecting spring, wherein the vibration-absorbing mass is movably attached to the base by the connecting spring, and in particular the base is attached to an insulating device, thus enabling a simple and reliable vibration absorber.

[0008] The natural frequency of the vibration absorber is matched to the natural frequency of the electrode, and the mass of the vibration-absorbing mass and the distance between the vibration-absorbing mass and the base are determined. The vibration absorber comprises two vibration-absorbing masses and two connecting springs, and the two vibration-absorbing masses are identical or different and / or attached to the base at the same or different distances from the base by each connecting spring, allowing the single or multiple natural frequencies of the vibration absorber to be set in a simple manner.

[0009] Each vibration-absorbing mass is attached to the base by a corresponding connecting spring. In particular, the vibration-absorbing masses and the base are arranged in a line, with the base positioned between two vibration-absorbing masses. The vibration absorber has two different natural frequencies; for example, multiple vibration-absorbing masses are arranged at different distances from the base but with the same mass.

[0010] For structural simplification, at least one vibration-absorbing mass is a weight and / or at least one connecting spring is an elastic piece (elastic rod). In embodiments of the present invention, the thin-film pressing device comprises two insulating devices extending from one of two opposing mounting devices toward the other. The insulating devices ensure that arc sparks on the cooling roll are avoided.

[0011] For example, an insulating device that extends only outside the thin film region will have an overlapping region of 2 mm to 15 mm in the thin film or thin film region. Insulating devices include insulating tubes, insulating enclosures, and / or insulating encapsulants. Vibration absorption is particularly effective when a substrate is attached to the insulating device.

[0012] The insulating absorber, i.e., the substrate, is connected to an insulating device, for example, by screws, by tools, by adhesives, and / or by mechanical connections. In one embodiment of the present invention, at least one electrode is strip-shaped or wire-shaped, in particular a wire that specifically forms an electric field. The use of a strip electrode creates a homogeneous electric field, which can reduce high voltages—same adhesion effect—and reduce arc sparks.

[0013] In one embodiment of the present invention, at least one electrode can be moved vertically between a first installation device and a second installation device, and in particular, at least one rotating coil for partially winding at least one electrode is provided in both the first and second installation devices. Therefore, deposits on the electrode that affect the quality of the electric field can be removed by movement or rotation.

[0014] In one embodiment of the present invention, the installation area comprises an axial thin-film region corresponding to the region of the cooling roll to which the thin film is attached, and at least one vibration absorber is positioned outside the thin-film region. In the thin-film pressing device of the present invention, damage to the thin film by the vibration absorber is limited. In particular, to reliably absorb vibrations, two vibration absorbers are provided for each electrode, positioned in the outer regions on both sides of the thin-film region.

[0015] To form a more homogeneous electric field, the thin film pressing device comprises at least two electrodes, at least two insulating devices, and at least two vibration absorbers, wherein the vibration absorbers are attached to the insulating devices of different electrodes, and in particular the vibration absorbers of different electrodes are positioned on the same side or different sides of the thin film region. The first electrode is strip-shaped or wire-shaped, in particular wire, and the second electrode is strip-shaped or wire-shaped, in particular wire.

[0016] In particular, the multiple electrodes are arranged parallel to each other and / or each has two sides. In one embodiment of the present invention, the first and / or second installation device includes a damping device configured to dampen vibrations of electrodes placed in the installation area. The damping device dampens vibrations very quickly. In one embodiment of the present invention, the damping device includes a damping roll, the axis of rotation of the damping roll is perpendicular to the longitudinal direction and also perpendicular to the width direction of the electrodes, the damping roll is mounted to be rotatable in the width direction and contacts the edge of each electrode, particularly the edge spaced away from the cooling roll.

[0017] For example, the damping device includes a damping roll for each electrode, the axis of rotation of the damping roll being perpendicular to the longitudinal direction and parallel to the width direction of the electrode, and in particular each electrode being in contact with one of the damping rolls. The insulating device is attached to the damping device by at least one damper made of an elastic material.

[0018] The object of the present invention is solved by a casting apparatus comprising a slot mold, particularly a grounded cooling roll and the thin film pressing device. The object of the present invention is solved by a thin film manufacturing apparatus comprising the casting apparatus and a stretching device such as a transverse, longitudinal and / or simultaneous stretching device having a heating furnace. The features and advantages described for the thin film pressing device are similarly applicable to the casting apparatus and / or thin film manufacturing apparatus, and conversely, the features and advantages of the casting apparatus and / or thin film manufacturing apparatus are also applicable to the thin film pressing device. [Brief explanation of the drawing]

[0019] Other features and advantages of the present invention will become apparent from the following description with respect to the attached drawings. The attached drawings are shown below: [Figure 1] Perspective view of a thin film manufacturing apparatus equipped with a cooling roller device according to an embodiment of the present invention. [Figure 2] A perspective view of a cooling roll device according to an embodiment of the present invention, Figure 1, which includes a thin film pressing device. [Figure 3] Figure 2 is a plan view of the thin film pressing device. [Figure 4] Perspective view of the insulating device of the thin-film pressing device equipped with a vibration absorber (Figure 2). [Figure 5] Perspective view of the vibration absorber in Figure 4. [Figure 6] Side view showing a second embodiment of the vibration absorber. [Figure 7a] Vertical displacement diagram of the electrode after excitation of the thin-film pressing device. [Figure 7b] Horizontal displacement diagram of the electrode after excitation in a thin-film pressing device equipped with a vibration absorber. [Figure 8] Perspective view of one of the installation devices shown in Figure 2 [Figure 9] Figure 8 is a perspective view showing the damping device of the installation apparatus. [Figure 10] Perspective view of the vibration absorber of the thin film pressing device according to the third embodiment of the present invention [Figure 11] Cross-sectional view of the electrode and insulation device according to the fourth embodiment of the present invention

Embodiments for Carrying Out the Invention

[0020] FIG. 1 shows a perspective view of a manufacturing apparatus 10 for a thin film F provided with a plurality of different devices. Although the thin film manufacturing apparatus 10 shows a continuous thin film manufacturing apparatus which is merely an example of an embodiment of the present invention, this cannot be a basis for limiting the scope of the claims of the present invention.

[0021] In the illustrated embodiment, the thin film manufacturing apparatus 10 includes an extrusion device 12, a casting device 14, at least one longitudinal stretching device 16 (MDO, “longitudinal orienter”), a transverse stretching device 18 (TDO, “transverse orienter”), a processing device 20, and a winding device 24. The extrusion device 12 includes an extruder that creates molten resin from at least one starting material (product).

[0022] The single or plural extruders are, for example, a single screw extruder, a cascade extruder, and / or a twin screw extruder. Other mixing processing devices such as a planetary roll extruder are also used. The molten resin created by the extruder is supplied onto the cooling roll 28 of the casting device 14 by the nozzle 26 of the slot die that forms the thin film.

[0023] Similarly, molten resin can be created by a polymerization reaction. For this purpose, monomers (including optional additives such as catalysts) are mixed and polymerized in a reactor and / or in the extruder of the extrusion device 12. The resulting polymerized molten resin is directly supplied and arranged onto the cooling roll 28 of the casting device 14 through the nozzle 26 that manufactures the thin film F. The thin film F to be manufactured has a single layer or a plurality of layers. A multilayer thin film formed by a single extruder with a plurality of layers or all layers or a multilayer thin film formed by a single extruder forming each layer can also be manufactured. Thereafter, the thin film F is supplied to the longitudinal stretching device 16 and stretched longitudinally.

[0024] For example, the transverse stretching apparatus 18 disclosed in German Patent Application Publication No. 102021128332 comprises a heating furnace 30 having several different regions for controlling the temperature of the thin film F along the normal direction of movement or tension of the thin film manufacturing apparatus 10. In the heating furnace 30, the thin film F is heated in a known manner and stretched by the transverse stretching apparatus 18 in a uniaxial direction or, in the illustrated embodiment, in a biaxial transverse direction to produce the thin film F.

[0025] The selective processing apparatus 20 is an apparatus that activates the surface of the thin film F, for example by corona treatment, to form an improved metal deposition layer. Corona treatment can be performed on one or both sides of the thin film. The winding apparatus 24 has the function of winding up the thin film F to be manufactured and is the final apparatus in the tensile direction. The winding apparatus 24 has a winding core for winding the thin film F.

[0026] Figure 2 shows an enlarged perspective view of the casting apparatus 14 (also called the "cooling roll apparatus"). The illustrated casting apparatus 12 comprises a slot mold 26, a cooling roll 28, and a thin film pressing device (pinning device) 32. Figure 3 shows a plan view of the thin film pressing device 32. The cooling roll 28 is also called a chill roll.

[0027] A slot mold 26 positioned above the cooling roll 28 continuously supplies molten resin to the cooling roll 28 to form a thin film F. The resin material used is, in particular, polyethylene terephthalate (PET). Other resin materials can be used in the same way. The thin film pressing device 32 uniformly adheres the thin film F to the cylindrical surface of the cooling roll 28. The cooling roll 28 shown in Figure 2 is rotated counterclockwise. In the illustrated embodiment, after the cooling roll 28 has rotated approximately 3 / 4 of a turn, the formed thin film F is finally peeled off the cooling roll 28, but if necessary, the thin film F is further cooled and supplied to the longitudinal stretching device 16.

[0028] The thin film pressing device 32, which uses static electricity to bring the thin film F into contact with the cooling roll 28, comprises at least one electrode 34, two mounting devices having a first mounting device 36 and a second mounting device 38, a selective low voltage source 40, a high voltage source 42, at least one vibration absorber 44, and at least one insulating device 46. In the illustrated embodiment, the low voltage source 40 and high voltage source 42, which are represented by a single power supply device, can also be used as multiple individual devices.

[0029] The first mounting device 36 and the second mounting device 38 are positioned in the axial direction of the cooling roll 28, either in front of or behind the cooling roll 28. The mounting area A shown in Figure 3 is provided between the first mounting device 36 and the second mounting device 38, and a thin film area B corresponding to the area of ​​the thin film F on the cooling roll 28 is similarly provided in the mounting area A in the axial direction of the cooling roll 28. For example, the thin film area B corresponds to the mounting area A corresponding to the axial region of the cooling roll 28 where the thin film F contacts the cooling roll 28.

[0030] The installation area A has a thin-film area B that is spaced apart from the first installation device 36 and the second installation device 38, and two outer areas C located on both sides of the thin-film area B, with outer areas C formed between the thin-film area B and the first installation device 36, and between the thin-film area B and the second installation device 38, respectively. The electrodes 34, which are individually attached to the first installation device 36 and the second installation device 38, extend the installation area A between the first installation device 36 and the second installation device 38.

[0031] The electrode 34 in the illustrated example has a strip-like width that is orders of magnitude longer than the electrode thickness. Furthermore, the electrode 34 has a length that is orders of magnitude greater than its width. The electrode 34 has two sides and two side edges extending in the longitudinal and width directions. One side edge of the electrode 34 faces the cooling roll 28, and the other side edge is positioned on the opposite side of the cooling roll 28. The direction between the two side edges of the same electrode 34 relates to the width direction of the electrode 34. In particular, the width direction of the electrode 34 corresponds to the radial direction of the cooling roll 28.

[0032] The width of the electrode 34 is, for example, 3 mm to 15 mm, particularly equal to or greater than 4 mm and less than 13 mm. For example, a width of 12.7 mm is considered. The shape of the electrode 34 is not limited to a strip shape, but may also be, for example, a wire with a round cross-section, or even a wire. Almost all other cross-sectional shapes of electrodes are also acceptable.

[0033] The electrode 34 is positioned behind the slot mold 26 in the rotational direction of the cooling roll 28. For example, the electrode 34 has a thickness of the thin film F on the cooling roll 28 and a distance from the cooling roll 28, for example, at least 2 mm. The electrode 34 is at most 20 mm from the cooling roll 28. A high voltage from a high voltage source 42 is applied to the electrode 34. The high voltage is, for example, in the range of 5kV to 10kV, and especially 7kV to 9kV.

[0034] When a high voltage is applied to the electrode 34, a strong electric field is formed in the installation area A of the cooling roll 28 that guides the thin film F. The strong electric field generates a low current called a pressing current that causes the thin film F to adhere to the cooling roll 28. At a high voltage of 20kV, the pressing current is, for example, about 30mA. At a high voltage of 9kV, the pressing current generated is about 12mA.

[0035] If electrode 34 fails, the power supply to the high-voltage source will also stop. The failure of electrode 34 can be detected by detecting the edge signal of the power pulse of the high-voltage source. In addition, a low voltage from the low-voltage source 40 is applied to electrode 34. For example, the low voltage is less than 150V, especially between 60V and 130V, for example, 120V. The high voltage and low voltage can be connected in series.

[0036] In addition to the electrode 34, a second hollow insulating device 46 is provided, which is fixed to the mounting devices 36 and 38 that face each other. For example, in the illustrated embodiment, the insulating device 46 extends toward each other from each mounting device 36 and 38.

[0037] The insulating device 46 extends from the outer region C of the installation region A toward the thin film region B. The insulating device 46 covers the entire outer region C to avoid electrical sparks to the cooling roll 28 and prevent damage to the cooling roll 28, and in particular extends exclusively to the outside of the thin film region B. Alternatively, the insulating device 46 may overlap the film region B by, for example, 2 mm to 5 mm for each insulating device 46. Alternatively, the entire outer region C may not be covered by the insulating device 46, and the ends of the insulating device 46 may be spaced away from the thin film region B.

[0038] The electrode 34 is continuously positioned through both insulating devices 46 in the installation area A between the installation devices 36 and 38. Specifically, the electrode 34 is inserted into the insulating device 46 from the first installation device 36, and once inserted into the insulating device 46, the electrode 34 is positioned within the insulating device 46, and the electrode 34 further extends into the outer area C within the insulating device 46. At the inner end of the insulating device 46, the electrode 34 is exposed from the insulating device 46 and penetrates the thin film area B. At the starting point of the other insulating device 46 in the other outer area C, the electrode 34 is inserted into the other insulating device 46 and extends toward the installation device 38.

[0039] It will be understood that the electrode 34 can be moved longitudinally between the two mounting devices 36 and 38. For this purpose, in the embodiment below, a rotatable coil 60 around which the electrode 34 is partially wound is provided on the first mounting device 36 and the second mounting device 38. In this embodiment, a coil device can also be formed instead of mounting devices. The electrode 34 is subjected to a mechanical tension between the first mounting device 36 and the second mounting device 38, for example, with a force of 200 N. The electrode 34 has a specific natural frequency that depends on the mechanical tension, the width of the electrode 34, and the length of the mounting area A.

[0040] Figure 4 is a perspective view showing a vibration absorber (vibration absorbing mass, vibration absorbing weight) 44 having one insulating device 46 and an electrode 34. For simplicity, the corresponding mounting devices 36 and 38 are not shown. The electrode 34, which is freely movable inside the insulating device 46, can move along the insulating device 46.

[0041] As shown in the figure, the insulating device 46 is, for example, an insulating tube, an insulating cover, and / or an insulating sleeve, and has a substantially rectangular longitudinal cross-section. For example, the corners of the insulating device 46 are rounded or chamfered by curved regions. In this embodiment, the longitudinal inner diameter of the insulating device 46 corresponds to the width of the electrode 34, so the electrode 34 is guided within the insulating device 46.

[0042] In the illustrated embodiment, each insulating device 46 completely surrounds the electrode 34 that it encloses along its outer circumference. However, complete surrounding is not required, as long as each insulating device 46 surrounds the electrode 34 on the side facing the cooling roll 28.

[0043] The insulating device 46 is manufactured from resins such as polyether ether ketone (PEEK), particularly tempered polyether ether ketone. Insulating devices 46 composed of tempered polyether ether ketone have been found to be particularly durable. Other materials that can be used to manufacture the insulating device 46 include, for example, polytetrafluoroethylene (PTFE), polyphthalamide (PPA), and polyether ketone (PEK), as long as they have sufficient high dielectric strength and dimensional stability in high-temperature environments exceeding 150°C.

[0044] As shown in the perspective view of Figure 5, the vibration absorber 44 is attached to the insulating device 46. The vibration absorber 44 is attached to the insulating device 46 in such a way that it is firmly seated on the insulating device 46, but the mobility of the electrodes 34 of the insulating device 46 is not affected.

[0045] In the illustrated embodiment, the thin-film pressing device 32 includes, for example, two vibration absorbers 44 having the same structure. Each vibration absorber 44 comprises a base body 48, two vibration-absorbing masses (vibration absorbers) 50, and two connecting springs 52. The base body 48, such as the insulating device 46, is manufactured from a resin such as polyether ether ketone (PEEK). Polyether ether ketone is temperable. Other materials for manufacturing the base body 48 can also be considered, such as polytetrafluoroethylene (PTFE), polyphthalamide (PPA), and polyether ketone (PEK), as long as they have sufficiently high dielectric strength and dimensional stability in high-temperature environments exceeding 150°C.

[0046] The base body 48 has a connecting region 56 to which the gripping portion 54 and the connecting spring 52 are fixed. The gripping portion 54 and the connecting region 56 are provided as a combined unit that is integrated with the base body 48. For example, the base body 48 is an injection-molded body or a three-dimensional printed body made of resin. Other materials such as metal or a mixture of metal and resin can be used in the same way.

[0047] The gripping portion 54 has the function of attaching the insulating device 46, and in the illustrated embodiment, it acts as a fastener. When attached, the gripping portion 54 connected to the insulating device 46 fixes the vibration absorber 44 in place. For example, the gripping portion 54, which acts as a fastener, can be securely fixed with screws. The base body 48 can be screwed to or connected to the insulating device 46.

[0048] Similarly, the vibration absorber 44 comprises a single vibration-absorbing mass 50, two or more vibration-absorbing masses 50, or a single connecting spring 52 or two or more connecting springs 52. In the illustrated embodiment, the vibration-absorbing mass 50 is, for example, a weight such as a cylindrical body made of a solid material. The material of the vibration-absorbing mass 50 is, for example, lead, steel, resin, aluminum, or a mixture thereof.

[0049] Similarly, the weights can be formed into all other shapes, such as cubes, hexahedrons, cones, circles, and spheres. In the illustrated embodiment, the connecting spring 52 is an elastic piece. Each vibration-absorbing mass 50 is attached to the connecting region 56 of the base 48 by the connecting spring 52. The connecting spring 52 is positioned axially, i.e., parallel to the electrode 34.

[0050] As shown in Figures 5 and 6, for example, the connecting spring 52 extends outwards from the connecting region 56 in a cantilevered manner in opposite directions, so the vibration-absorbing mass 50 is similarly positioned opposite each other with respect to the base 48. The base 48 is positioned axially between the two vibration-absorbing masses 50. The two vibration-absorbing masses 50 and the base 48 are positioned linearly along the extension direction of the connecting spring 52.

[0051] Since the connecting spring 52 allows the vibration-absorbing mass 50 to move, the vibration-absorbing mass 50 is positioned to be movable at a certain distance from the base 48. In the illustrated embodiment of the present invention, the first vibration-absorbing mass 50 and the second vibration-absorbing mass 50 are positioned at a distance of a first distance a1 and a second distance a2, respectively, from the base 48.

[0052] The vibration absorber 44 has at least one natural frequency based on the mass of the vibration absorbing mass 50 and the first distance a1 and second distance a2 from the base 48. The vibration absorber 44 can also enjoy multiple natural frequencies, for example, two natural frequencies, as shown in the exemplary embodiment. In the exemplary embodiment, the masses of both vibration absorbing masses 50 are the same, but the distances a1 and a2 from the base 48 are different, so two different natural frequencies occur in the vibration absorber 44.

[0053] Similarly, since the first distance a1 and the second distance a2 from both vibration-absorbing masses 50 to the base 48 are the same, the vibration absorber 44 has only one natural frequency. The single or multiple natural frequencies of the vibration absorber 44 correspond to the natural frequencies of the electrodes 34. For example, in this embodiment, "corresponding" means that the natural frequencies corresponding to each other are either the same or differ from each other by at most ±10.

[0054] In particular, the natural frequency of the vibration absorber 44 corresponds to the lowest natural frequency of the electrode 34. For example, when a mechanical voltage of 200N is applied to an electrode 34 with a width of 12 mm and a length of 4.2 m, the natural frequency is approximately 24.8 Hz. The electrode 34 may have multiple natural frequencies. In particular, the electrode has higher harmonics of the lowest natural frequency as multiple natural frequencies. For example, one natural frequency of the vibration absorber 44 is 24.8 Hz, and the vibration absorber 44 is compatible with the above example of the electrode 34.

[0055] Figure 6 shows a vibration absorber 44 of a second embodiment of the thin film pressing device 32. When the vibration absorbing masses 50 have the same mass and are positioned at the same distance from the base 48, i.e., a1=a2, the vibration absorber 44 of this embodiment has only a single natural frequency. As is clear from Figure 3, the vibration absorber 44 of the thin film pressing device 32 of this embodiment is positioned on different sides of the thin film region B.

[0056] During the operation of the thin film manufacturing apparatus 10, a high-voltage field is formed between the electrodes 34 and the cooling roll 28 by the thin film pressing device 32, to which a high voltage is applied between the electrodes 34. Due to the rotational motion of the cooling roll 28, the thin film F passes through the electric field. Because of the electric field, the surface of the cooling roll 28 is electrostatically charged, and the polar molecules of the resin material of the thin film F align, so the electrostatic attraction generated between the cooling roll 28 and the thin film F causes the thin film F to adhere uniformly to the cooling roll 28.

[0057] For example, when vibration occurs in the electrode 34 during the operation of the thin film manufacturing apparatus 10 due to the influence of other factors such as arc discharge, non-uniformity of molten resin, non-uniform distribution of pressing additives, and ventilation, the electrode 34 vibrates at its natural frequency. When the vibration absorber 44 is attached to the insulating device 46, the vibration is transmitted to the vibration absorber 44, and the vibration absorbing mass 50 vibrates similarly, so the vibration absorber 44 vibrates at its natural frequency. The natural frequency of the vibration absorber 44 corresponds to the natural frequency of the electrode 34, and the vibration phase of the vibration absorber 44 is in the opposite direction to the vibration phase of the electrode 34, so the vibration of the electrode 34 is sufficiently attenuated.

[0058] Figure 7a shows two graphs representing the vertical vibration amplitude of the excited electrode 34. The lower graph shows the displacement, i.e., amplitude, of the electrode 34 of the thin-film pressing device 32 having a vibration absorber 44, while the upper graph shows the displacement of the electrode of the thin-film pressing device 34 without a vibration absorber.

[0059] Figure 7b shows two graphs representing the horizontal vibration amplitude of the excited electrode 34. The lower graph shows the horizontal displacement, i.e., amplitude, of the electrode 34 in a thin-film pressing device 32 with a vibration absorber 44, while the upper graph shows the horizontal displacement of the electrode in a thin-film pressing device 34 without a vibration absorber. It is clear that in the thin-film pressing device 32 with the vibration absorber 44, the displacement, i.e., amplitude, of the vibration amplitude of the electrode 34 is reduced and absorbed more significantly and rapidly than in the case without the vibration absorber. For example, the electrode 34 with the vibration absorber achieves damping more than three times faster than without it.

[0060] In this way, the arc discharge between the electrode 34 and the cooling roll 28 is reliably reduced, and the electrode 34 is hardly immersed in the splash of molten resin from the slot mold 26. Furthermore, during the operation of the thin film pressing device 32, the movable electrode 34 moves continuously along its length, is not wound around the first mounting device 36, but is wound around the second mounting device 38, and the same effect is achieved in the reverse direction as well. In this way, adhesion caused by the evaporation of the resin material of the thin film F is removed, and the homogeneity of the electric field is increased or maintained.

[0061] Adhesion is also reduced by the low voltage applied to the electrode 34. A current, i.e., a heating current of 1A to 8A, is formed by the low voltage through each electrode 34 from the first installation device 36 to the second installation device 38. For example, the amount of current passing through the electrode 34 provided as a 3mm metal strip is 2A to 2.5A, and the amount of current passing through the electrode 34 provided as a 12.7mm metal strip is approximately 7A. The current value is low when using wire as the electrode 34.

[0062] Since a failure of electrode 34 leads to an interruption of the current, the electrode is not grounded. Although electrode 34 is heated by the current, the evaporating resin material of the resin thin film F hardly adheres firmly to electrode 34 as a condensed substance. The quality of the resulting thin film F is clearly improved, and machine downtime can be significantly reduced.

[0063] Figures 8 and 9 show the mounting device 38 for the thin film pressing device 32, with Figure 8 showing the second mounting device 38 in the open position and Figure 9 showing the fixed state of the corresponding insulating device 46 of the second mounting device 38. The first mounting device 36 is designed for this purpose.

[0064] Figure 8 shows the second mounting device 38 in an open state, located to the left of the cooling roll 28 in Figure 2. The first mounting device 36, located to the right of the cooling roll 28, has substantially the same structure as the second mounting device 38 and is arranged symmetrically in a mirror image. The second mounting device 38 comprises a housing 58, a rotatable coil 60, a voltage application device 62, a first guide roll 64, a mechanical tensioning device 66, and a damping device 70.

[0065] The electrode 34 is partially wound around a rotating coil 60 and connected from the rotating coil 60 to a voltage application device 62. The voltage application device 62, which has a roller 72, is electrically connected to a high voltage source 42. The roller 72 guides the electrode 34 and applies the high voltage supplied by the high voltage source 42 to the electrode 34 while the high voltage source 42 is operating.

[0066] Subsequently, the electrode 34 is sent to the first guide roller 64 and then to the installation area A from the installation device 38. In the first installation device 36, the electrode 34 moves in the reverse direction and is finally returned to the rotary coil 60 from the second installation device 38.

[0067] The electrodes 34 can be moved between the first and second installation devices 36 and 38 by driving the coils 60 of the first and second installation devices 36 and 38. For example, the electrodes 34 can be unwound from the coils 60 of the first installation device 36 and sent from the installation area A to the second installation device 38, and then wound up by the coils 60 of the second installation device. The tension or mechanical stress and natural frequency of the electrodes 34 can also be set by the driving coils 60.

[0068] It will be understood that multiple electrodes 34 can be wound onto the same coil 60. For example, a common coil 60 with different regions is provided for different electrodes 34. The mechanical stress and natural frequency of multiple different electrodes 34 can be set for each electrode 34 using a tensioning device. Multiple damping devices 70 represent the exit points of the electrodes 34 of the first mounting device 36 and the second mounting device 38. Damping devices 70 are provided on arms 62 extending from the housings 58 of each mounting device 36, 38 in the direction of mounting region A.

[0069] For example, the length of the arm jib 62 can be adjusted, particularly by the motor rack and pinion mechanism. As shown in Figure 9, the insulating device 46 is attached to the damping device 70 by the mounting device 80. A vibration damper 82, such as a damper having an elastic material that clamps the insulating device 46, is provided on the mounting device 80. For example, the structure that clamps the insulating device 46 can be adjusted with screws.

[0070] Figure 9 shows an enlarged perspective view of a damping device 70 having damping rolls 84 attached to each mounting base 86. Each mounting base 86 elastically contacts the side surface of the electrode 34 at a right angle.

[0071] Each of the multiple damping rolls 84 can rotate around an axis of rotation that is perpendicular to the longitudinal direction and parallel to the width direction of the electrode 34. The electrode 34 is guided through two damping rolls 84, and each damping roll 84 is in contact with the side surface of the electrode 34.

[0072] The damping device 70 dampens the vibrations of the electrode 34, causing the vibrations of the electrode 34 to decay rapidly and evenly. Other damping devices, such as those disclosed in German Patent Application Publication No. 102022118971, are also available. In other embodiments of the present invention, it is preferable that each of the two electrodes 34, provided through at least one insulating device 46, passes through two insulating devices 46.

[0073] When two electrodes 34 are provided, at least two vibration absorbers 44 are provided, and one vibration absorber 44 is attached to the insulating device 46 of each electrode 34 to provide the natural frequency of the corresponding electrode 34. The vibration absorber 44 of the other electrode 34 can be placed on the same side of the thin film region B, for example, adjacent to or facing each other, on different sides of the thin film region B.

[0074] If the two electrodes 34 have different natural frequencies, the same vibration absorber 44 described in the first embodiment can be used if the two natural frequencies of the vibration absorber 44 correspond to the different natural frequencies of the two electrodes 34. When one vibration absorber 44 is provided for each insulating device 46, it can also be considered to use four vibration absorbers 44 by using two electrodes 34.

[0075] Figures 10 and 11 show alternative embodiments substantially corresponding to the first and second embodiments. Therefore, identical parts are denoted by the same reference numerals, and only the differences are described. In the description of alternative embodiments related to the first and second embodiments, the features of all embodiments will readily combine.

[0076] Figure 10 shows a perspective view of the vibration absorber 44 of the thin film pressing device 32 according to the third embodiment. In this embodiment, the vibration absorbing mass 50 is formed in a U-shaped cross-section with its apex attached to the connecting portion 52, and the legs of the U-shaped cross-section extend toward the base 48, with the ends of the legs being formed to be thicker.

[0077] The vibration absorber 44, having four natural frequencies, is suitable for many different electrodes 34 and / or different installation methods, particularly mechanical stresses. Figure 11 shows a cross-sectional view of the electrode 34 and the associated insulating device 46 of the fourth embodiment. In this embodiment, the electrode 34 is a wire with a circular cross-section. Thus, the insulating device 46 corresponds to the cross-section of the electrode 34. The insulating device 46 has a ring-shaped cross-section in which the electrode 34 is placed.

Claims

1. A thin film pressing device for electrostatically attaching a thin film (F) to a cooling roll (28) comprising a first installation device (36), a second installation device (38), an installation area (A) positioned between the first installation device (36) and the second installation device (38), a high voltage source (42), an electrode (34), at least one insulating device (46), and at least one vibration absorber (44), At least one insulating device (46) extends from the associated mounting device (36, 38) to the thin film region (B), The electrode (34) extends from the first fixed area (36) to the second fixed area (38) of the installation area (A) via at least one insulating device (46), and a high voltage is applied to the electrode (34) by a high voltage source (42). A thin-film pressing device characterized in that a vibration absorber (44) is attached to at least one insulating device (46) to absorb vibrations of the electrode (34).

2. The thin film pressing device according to claim 1, wherein the vibration absorber (44) has a natural frequency corresponding to the natural frequency of the electrode (34).

3. The thin film pressing device according to claim 1, wherein the vibration absorber (44) has a natural frequency corresponding to the lowest natural frequency of the electrode (34).

4. The thin film pressing device according to claim 1, wherein the vibration absorber (44) comprises a base (48), at least one vibration absorber (50), and at least one connecting spring (52), the vibration absorber (50) being movably attached to the base (48) by the connecting spring (52).

5. The thin film pressing device according to claim 4, wherein the substrate (48) is attached to the insulating device (46).

6. The vibration absorber (44) comprises two vibration absorbers (50) and two connecting springs (52). The two vibration absorbers (50) are the same or separate and / or are connected by a connecting spring (52) at an equal distance (a) or different distances (a) from the base (48). 1 , a 2 The thin film pressing device according to claim 4, which is attached to a substrate (48) by ).

7. The thin film pressing device according to claim 4, wherein at least one vibration absorber (50) is a weight and / or at least one connecting spring (52) is an elastic piece.

8. The thin film pressing device (32) is further comprising two insulating devices (46) extending toward each other from each of the opposing mounting devices (36, 38), as described in claim 1.

9. The thin film pressing device according to claim 1, wherein at least one electrode (34) is strip-shaped, wire-shaped, or wire.

10. The thin film pressing device according to claim 1, wherein at least one electrode (34) moves in the longitudinal direction of the electrode (34) between the first installation device (36) and the second installation device (38).

11. The thin film pressing device according to claim 10, comprising a first installation device (36) and a second installation device (38), and at least one rotatable coil (60) that is partially wound around at least one electrode (34).

12. The thin film pressing device according to claim 1, wherein the installation area (A) comprises a thin film portion (B) corresponding to the cooling roll (28) portion to which the thin film is attached, and at least one vibration absorber (44) is positioned outside the thin film portion (B).

13. The thin film pressing device (32) is further comprising two vibration absorbers (44) positioned on opposite sides of the thin film portion (B) according to claim 12.

14. The thin film pressing device (32) comprises at least two electrodes (34), at least two insulating devices (46), and at least two vibration absorbers (44), wherein the vibration absorbers (44) are attached to the insulating devices (46) of different electrodes (34), as described in claim 1.

15. The thin film pressing device according to claim 14, wherein the vibration absorbers (44) of different electrodes (34) are arranged on the same side or on different sides with respect to the thin film portion (B).

16. The thin film pressing device according to claim 1, wherein the first installation device (36) and / or the second installation device (38) comprises a damping device (70) for damping vibrations of the electrodes (34) in the installation area (A).

17. A casting apparatus comprising a slot mold (26), a cooling roll (28), and a thin film pressing device (32) according to any one of claims 1 to 16.

18. The casting apparatus according to claim 17, wherein the cooling roll (28) has a circular cross-section.

19. A thin film manufacturing apparatus characterized by comprising a casting apparatus (12) as described in claim 17 and a stretching apparatus (16, 18) having a heating furnace (30).

20. The thin film manufacturing apparatus according to claim 19, wherein the stretching apparatus (16, 18) is a transverse stretching apparatus and / or a simultaneous stretching apparatus.

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