Film processing line for producing plastic film web and method for cleaning components of film processing line for producing film web

Abstract

The invention relates to a film processing line, in particular a cast film, calendered film or blown film line, for producing a plastic film web, comprising the following features: a) the film processing line is provided with a machine unit along which the film web is conveyed via the film processing line, and b) the film processing line is provided with a roller unit for treating the film material, and c) the roller unit is provided with at least one film roller in contact with the film web, characterized by the following other features: d) the film processing line is provided with a cleaning unit, the surface of at least one film roller of the roller unit in contact with the film web can be cleaned by the cleaning unit in an operating state. The invention also relates to a cleaning unit for a film processing line according to the invention and to a method for cleaning components of a film processing line for producing a film web.

Description

[0001] The present invention relates to a film processing line for producing plastic film webs, in particular a cast film, calendered film or blown film line, a cleaning device for the film processing line, and a method for cleaning components of a film processing line for producing film webs, in particular a cast film, calendered film or blown film line.

[0002] In film processing lines, deposits from melted plastic ("sheet shedding") can cause contamination on the roller surface, where the contamination is formed by condensation or other products of the substance from which the product was extruded. This can have negative effects on the film produced, such as differences in glossy or matte areas, spots or streaks, and inclusions. This leads to a reduction in film quality and, in the worst case, makes the film unusable. When contamination reaches a certain level, cleaning and / or polishing is necessary.

[0003] It is known in the prior art that the rollers of film processing lines must be cleaned regularly. However, thorough cleaning can only be carried out when the machine is out of operation. On the one hand, this leads to production losses due to shutdowns and startups and line downtime, and on the other hand, personnel are required to carry out the cleaning.

[0004] The object of the present invention is to provide an improvement or alternative to the prior art. In particular, the object of the present invention is to provide a cleaning solution that is performed without human intervention and, if possible, during operation of a film processing line.

[0005] According to a first aspect, the object is achieved by a film processing line for producing a plastic film web, in particular a cast film, calendered film or blown film line, comprising the following features: a machine direction in which the film web is transported through the film processing line, a roll arrangement for handling or guiding the film material and at least one film roll in contact with the film web. Furthermore, the film processing line is provided with a cleaning device, by which the surface of at least one film roll of the roll arrangement in contact with the film web can be cleaned in the operating state.

[0006] The following terms are used to explain the present invention.

[0007] It is expressly pointed out that within the scope of this patent application, indefinite articles and indefinite numbers, such as "one", "two", etc., should generally be understood as "at least one", "at least two", etc., unless it is clear from the context or the specific text of a particular paragraph that only "exactly one" and "exactly two", etc. are meant. Furthermore, all numbers and all information about process parameters and / or equipment parameters are to be understood in the technical sense, i.e. taking into account the usual tolerances. Even if the restrictive wording "at least" etc. is explicitly stated, this does not mean that the simple use of "one" without the use of "at least" or similar words means "exactly one".

[0008] In other words, the machine direction is to be understood as the particular direction in which the raw material is processed into a film web. In the context of the present invention, a roller arrangement preferably refers to a mechanical arrangement of at least one film roller, which in turn is configured to have a forming effect on the film web. The roller arrangement may also have corresponding electronic control devices and drives, such as motors. In the context of the present invention, the term "operating state" may describe the state in which the film processing line produces a film web, that is, the film processing line is active. Simply put, the operating state is the state in which the film processing line is running, started, shut down, or in particular when a roll change is performed. In the context of the present invention, a cleaning device is to be understood in particular as a system configured to remove contaminants from the surface of a roller. In addition, the cleaning device may be configured to perform cleaning of the film roller at specified intervals or continuously.

[0009] In one embodiment of the first aspect of the invention, the cleaning device is particularly configured to at least partially remove a coating on the surface of the film roller in contact with the film web. In the context of the present invention, the term "removal" is preferably understood to mean the removal of contaminants from the film roller, for example by wiping, scraping, brushing, rubbing or similar methods. In addition, "removal" may also mean the non-contact removal of contaminants from the film roller, for example by evaporation, burning or the like, so that in this case, the elements of the cleaning device are not in direct contact with the film roller. The film roller may have a desired coating, the so-called working coating, or may not have a working coating. Therefore, the coating may also optionally include a working coating of the film roller. In other words, an unwanted coating may also be understood as a deposit or an accumulation layer on the surface of the film roller or the optional working coating.

[0010] For example, the cleaning device is also configured to transfer the coating at least partially to the film web. For this purpose, the coating can first be collected or, alternatively, be directed directly toward the film web. The term "coating" is to be understood in particular as contaminants located on the film roll and, optionally, as described above, also as a working coating of the film roll. The working coating preferably remains on the film roll while the contaminants are removed and, if necessary, is at least partially transferred to the film web.

[0011] It is conceivable that the cleaning device is provided with cleaning elements for contactless removal of the coating. In particular, this means that no element of the cleaning device is in contact with the film roller.

[0012] It is conceivable that the cleaning device is provided with a cleaning element for abrasive removal of the coating. In the context of the present invention, abrasive is to be understood in particular as the presence of friction, the abrasive effect leading to smoothing, cleaning or abrasion. For this purpose, the cleaning device can be arranged in the immediate vicinity of the film roller and preferably has a cleaning element which is in contact with the film roller at least at certain intervals or continuously in order to abrasively remove the coating on the film roller. For this purpose, the cleaning element can have, for example, at least one polishing element, a wiper or the like.

[0013] Furthermore, the cleaning element optionally comprises a laser, which is configured to remove the coating. A laser is to be understood in particular as a laser system which also comprises at least one control system and a suction device. The laser system can also have a beam expander, a reflector and a focusing lens. In particular, the laser ensures that the coating evaporates, burns or melts, wherein in the latter case, the coating can be reflected at least partially back onto the film web.

[0014] The laser can be configured as a pulsed laser with a frequency between 50kHz and 300kHz, preferably between 150kHz and 200kHz. In addition, the laser has a power, in particular, the power is preferably between 2W and 30W. Alternatively, a more powerful laser can be provided, whose power can be between 30W and 100W. In a preferred embodiment, the laser can have a laser power of 6W to 10W. In a preferred embodiment, the laser can be configured to adjust the power of the laser within an adjustment range between 10% and 100% of the power. To this end, the laser can have a corresponding adjustment system. At a frequency of 50kHz, the laser in a specific embodiment has a pulse energy of 1 millijoule (mJ). In particular, the pulse energy is proportional to the average power and inversely proportional to the repetition rate of the laser. In addition, the laser preferably has a wavelength in the range between 400nm and 1200nm, in particular a wavelength between 1055nm and 1070nm. Alternatively, it is also conceivable that the laser is configured as a continuous laser, i.e. a continuous wave laser. In addition, the frequency and / or number and intensity of the power levels and wavelength of the selected laser can also vary according to the specific application to ensure that the film roll is cleaned without damaging the film roll. In the context of the present invention, a pulsed laser is particularly understood as a laser that does not emit light continuously, but works in a pulsed manner, that is, emits light in a limited time portion. In particular, the wavelength of the laser describes the spatial frequency of the emitted light wave. The optimal wavelength for a specific application depends essentially on the respective application. In the context of the present invention, the power of the laser, i.e. the power level of the laser selected in each case, is particularly understood as the optical output power of a continuous wave (CW) laser or the average power of a pulsed laser. A pulsed laser has a specific pulse duration, which is defined as the half-value width of the optical power of the laser over time. In the context of the present invention, the pulse duration is preferably between 100ns and 140ns. Optionally, the laser can also be configured as an ultrashort pulse laser with a pulse duration in the order of picoseconds to attoseconds. In the context of the present invention, the frequency is preferably understood as the pulse repetition frequency of the pulsed laser, which describes the number of pulses emitted per second or the inverse of the time pulse interval. The light of the laser is preferably randomly polarized, so that the emitted electric field points in random directions. Alternatively, the light of the laser can also be linearly polarized, so that the emitted electric field always points in the same direction. In addition, a laser has a specific beam diameter, which characterizes in particular the lateral extent of the light beam perpendicular to the propagation direction or the physical size of the light beam. The beam diameter determines the power / energy density of the laser beam or the optical power / energy per unit area. The larger the beam diameter, the lower the power / energy density of the light beam with constant power or energy. In addition, a laser has a beam profile, which describes the intensity distribution in the cross section of the light beam.Common beam profiles include, for example, Gaussian beams and flat-top beams, which have a Gaussian or rectangular beam profile. In addition, lasers have a divergence property, which describes how the beam widens with increasing distance relative to the beam waist of the laser due to diffraction and is defined by the half-angle of the laser. Another characteristic of a laser is the spot size, which describes the diameter of the beam at the focus of the focusing lens system. In order to maximize the power density, the spot size is preferably chosen to be as small as possible. For example, aspherical lenses can be used instead of traditional spherical lenses to reduce spherical aberrations and produce smaller spot sizes. There is a so-called working distance between the lasers or between the last optical element of the laser and the object, such as a coating on the surface of a thin film roll.

[0015] In another possible embodiment according to the first aspect of the present invention, the cleaning element comprises a steam applicator, which is configured to remove the coating with steam. The steam applicator is configured, for example, as an electric steam generator, which can provide steam with an adjustable temperature and an adjustable pressure. For this purpose, the steam applicator can also have a corresponding control device.

[0016] In addition, the steam can be water vapor. Alternatively, the steam can be a solvent from the group consisting of aprotic solvents, protic solvents and neutral solvents. The use of a solvent can facilitate the removal of the coating. For example, the solvent can be an organic solvent such as acetone, wherein the choice of solvent depends on the material of the film web.

[0017] In another possibility, the cleaning element comprises a plasma emitter, which is configured to remove the coating. The term plasma refers in particular to a gas that partially or completely consists of free charge carriers, i.e., ions or electrons. Therefore, the plasma emitter is preferably used to emit the gas onto the film roll to at least partially remove the coating.

[0018] Furthermore, it can also be provided that the cleaning device is provided with an applicator for applying a cleaning agent to the surface of at least one film roller in contact with the film web and / or to a coating on the surface. Within the scope of the invention, for example, a solvent such as acetone, a polishing paste and / or water is provided as a cleaning agent. The applicator can also have a control system so that the cleaning agent is applied to the surface of at least one film roller in contact with the film web or to a coating on the surface at certain time intervals or at specific times. Alternatively, the applicator can continuously apply the cleaning agent to the surface of at least one film roller in contact with the film web or to a coating on the surface.

[0019] For example, the cleaning device is configured as a cleaning unit having a housing, and the cleaning unit is formed with a moving unit that can be moved to clean the surfaces of multiple film rollers of the roller device in contact with the film web. To this end, the cleaning unit can have a track and / or a mounting system and a control system to move the cleaning unit between the film rollers of the roller device in contact with the film web. Within the scope of the present invention, it is conceivable that the cleaning device or cleaning unit has multiple cleaning elements, each of which is arranged on or near one of the multiple film rollers of the roller device in contact with the film web, so that the film rollers can be cleaned simultaneously, alternately or randomly. Multiple cleaning elements can also be provided to clean a single film roller. Multiple cleaning elements can be cleaning elements of the same type, that is, for example, abrasive or non-contact cleaning elements, or a combination of various types of cleaning elements.

[0020] According to a second aspect of the present invention, the above-mentioned object of the present invention is achieved by a cleaning device for a film processing line according to the present invention.

[0021] According to a third aspect of the invention, the object is achieved by a method for cleaning components of a film processing line for producing a film web, in particular a cast film, calendered film or blown film line, the method comprising the following steps: providing a film processing line; providing a roller arrangement for handling or conducting film material, the roller arrangement being provided with at least one film roller in contact with the film web; and providing a cleaning device, by means of which the surface of at least one film roller of the roller arrangement in contact with the film web can be cleaned in an operating state. In addition, the cleaning of the film roller in an operating state is performed by at least partially removing the coating on at least one film roller in contact with the film web of the roller arrangement. This is performed by a cleaning element, which can be configured as an abrasive or non-contact cleaning element. The application time of the cleaning element can vary depending on the cleaning situation. If laser cleaning is performed, the application time of the laser can be between 30 and 90 seconds, in particular between 50 and 70 seconds. Optionally, the removed coating is also partially or completely recycled. The removal can be performed up to the optional working coating of at least one film roller, or the working coating can also be partially or completely removed. In the absence of a working coating, the removal may be a partial or, in particular, complete removal of the coating.

[0022] Furthermore, cleaning can also be performed by lateral movement or full-surface cleaning. In other words, lateral movement is to be understood in particular as meaning that the cleaning element only partially covers the surface of the film roll axially, so that the surface is cleaned by moving back and forth. In the case of full-surface cleaning, the cleaning element completely covers the entire axial width of the film roll surface, so that the surface of the film roll is completely cleaned without having to move.

[0023] The present invention will be described in more detail below based on exemplary embodiments with reference to the accompanying drawings, in which:

[0024] Figure 1 shows a schematic diagram of a roller device having an abrasive cleaning element;

[0025] Figure 2 shows a schematic diagram of a roller device with a laser as a cleaning element;

[0026] Figure 3 shows a schematic diagram of a roller device with a steam applicator as a cleaning element;

[0027] Figure 4 shows a schematic diagram of a roller device with a plasma emitter as a cleaning element;

[0028] Figure 5 A schematic diagram of a roller arrangement with a laser as cleaning element and an additional applicator is shown.

[0029] Figure 1 A schematic diagram of a roller arrangement 3 according to the invention is shown, which roller arrangement 3 is part of a film processing line 1 (not shown), and in this exemplary embodiment has three film rollers 31. The film rollers 31 in turn have surfaces 311 on which a coating 5 accumulates during operation of the film processing line 1. The film web 2 is formed between the film rollers 31. Also shown is the machine direction MD, which indicates the direction from the raw material to the finished film web in the film processing line 1. Here, for example, the cleaning device 4 is also arranged on the first film roller 31. Within the scope of the invention, it is also conceivable that the cleaning device 4 is arranged on the second or third film roller 31, or on all film rollers 31 provided. Furthermore, the cleaning device 4 comprises a cleaning element 7, which in this embodiment is configured as an abrasive cleaning element 7.

[0030] Figure 2 and Figure 1 The arrangement in FIG. 1 differs only in that the cleaning element 7 is configured as a laser 71 and is therefore configured as a non-contact cleaning element 7. The laser beam acting on the coating 5 on the surface 311 of the film roller 31 is shown in dashed lines. The laser 71 is a pulsed laser with a frequency in the range between 150 kHz and 200 kHz. The laser 71 also has two power levels, wherein the first power level is between 10 W and 30 W and the second power level is between 30 W and 100 W. In addition, the wavelength of the laser 70 is between 400 nm and 1200 nm, in particular 1064 nm.

[0031] and Figure 1 and Figure 2 compared to, Figure 3As cleaning element 7 there is a steam applicator 72, shown as a dashed line, which applies steam 721 in the form of water vapor to the coating 5 on the surface 311 of the film roll 31. Applying a solvent is also a possible alternative.

[0032] Figure 4 Again, it shows Figure 1 In the arrangement of the roller device 3 in FIG. 1 , in this embodiment, the plasma emitter 73 is used as the non-contact cleaning element 7 .

[0033] Figure 5 A further embodiment according to the invention is schematically shown. Here, the cleaning device 4 is configured as a cleaning unit and has a housing 41. Furthermore, the cleaning unit comprises a cleaning element 7 in the form of a laser 71 and an applicator 8 for applying a cleaning agent 81 to the surface 311 of the film roller 31. In this exemplary embodiment, the cleaning unit is arranged on a track 9 so that the cleaning unit can be moved to the third film roller 31 to clean it. The track 9 is only intended to outline the concept according to the invention, i.e. in one embodiment, the cleaning unit can be movable and can be moved between the film rollers 31.

[0034] The embodiments shown here are only examples of the present invention and should not be interpreted as limiting. Alternative embodiments that occur to those skilled in the art are also included in the protection scope of the present invention.

[0035] List of reference numerals:

[0036] 1 Film production line

[0037] 2 Film web

[0038] 3-roller unit

[0039] 31 Film Roller

[0040] 311 Surface

[0041] 4 Cleaning device

[0042] 41 Shell

[0043] 5 Coating

[0044] 7 Cleaning components

[0045] 71 Laser

[0046] 72 Steam Applicator

[0047] 721 Steam

[0048] 73 Plasma Launcher

[0049] 8 Applicator

[0050] 81 Cleaner

[0051] 9 Tracks

[0052] MD Machine Direction

Claims

1. A film processing line (1) for producing a plastic film web (2), in particular a cast film, calendered film or blown film line, Features include: a. the film processing line (1) is provided with a machine direction (MD), the film web (2) being conveyed along the machine direction through the film processing line (1), and b. The film processing production line (1) is provided with a roller device (3) for handling or guiding the film material, and c. the roller arrangement (3) is provided with at least one film roller (31) in contact with the film web (2), It is characterized by the following further features: d. The film processing production line (1) is provided with a cleaning device (4), and the surface (311) of at least one film roller (31) of the roller device (3) in contact with the film web (2) can be cleaned by the cleaning device (4) in an operating state.

2. The film processing production line (1) according to claim 1, further comprising: Features include: a. The cleaning device (4) is configured to at least partially remove the coating (5) on the surface (311) of the film roll (31) in contact with the film web (2).

3. A film processing line (1) according to any one of the preceding claims, further comprising: Features include: a. The cleaning device (4) is configured to at least partially transfer the coating (5) to the film web (2).

4. A film processing line (1) according to any one of the preceding claims, further comprising: Features include: a. The cleaning device (4) is provided with a cleaning element (7) for contactless removal of the coating (5).

5. The film processing line (1) according to any one of the preceding claims 1 to 3, further comprising: Features include: a. The cleaning device (4) is provided with a cleaning element (7) for abrasively removing the coating (5).

6. A film processing line (1) according to any one of the preceding claims, further comprising: Features include: a. The cleaning element (7) comprises a laser (71) configured to remove the coating (5).

7. The film processing production line (1) according to claim 6, further comprising: Features include: a. The laser (71) is configured as a pulsed laser, preferably having a frequency between 50 kHz and 300 kHz, more preferably between 150 kHz and 200 kHz.

8. The film processing production line (1) according to claim 6, further comprising: Features include: a. The laser (71) has a power, wherein the power is in particular between 2 W and 30 W.

9. The film processing line (1) according to claim 6, further comprising the following features: a. The laser (71) has a wavelength between 400 nm and 1200 nm, in particular between 1055 nm and 1070 nm.

10. The film processing line (1) according to any one of the preceding claims, further comprising the following features: a. The cleaning element (7) comprises a steam applicator (72), which is configured to remove the coating (5) using steam (721).

11. The film processing line (1) according to claim 10, further comprising at least one of the following features: a. the steam (721) is water vapor, b. The steam (721) is a solvent selected from the group consisting of an aprotic solvent, a protic solvent and a neutral solvent.

12. A film processing line (1) according to any one of the preceding claims, further comprising: Features include: a. The cleaning element (7) comprises a plasma emitter (73), which is configured to remove the coating (5).

13. A film processing line (1) according to any one of the preceding claims, further comprising: Features include: a. The cleaning device (4) is provided with an applicator (8) for applying a cleaning agent (81) to the surface (311) of the at least one film roller (31) in contact with the film web (2) and / or the coating (5) on the surface (311).

14. A film processing line (1) according to any one of the preceding claims, further comprising: Features include: a. The cleaning device (4) is configured as a cleaning unit (7), the cleaning unit (7) having a housing (41), and b. The cleaning unit (7) forms a movable unit, which is movable to clean the surfaces (311) of the plurality of film rollers (31) of the roller arrangement (3) which are in contact with the film web (2).

15. A cleaning device (4) for a film processing line (1) according to any one of the preceding claims.

16. A method for cleaning components of a film processing line (1) for producing a film web (2), the film processing line (1) being in particular a cast film, calendered film or blown film line, the method The following steps are involved: a. Provide film processing production line (1), b. providing a roller device (3) for handling or guiding a film material, the roller device (3) being provided with at least one film roller (31) in contact with the film web (2), c. providing a cleaning device (4), by which the surface (311) of at least one film roller (31) of the roller device (3) in contact with the film web (2) can be cleaned in the operating state, d. Cleaning the at least one film roller (31) of the roller arrangement (3) in contact with the film web (2) in an operating state by at least partially removing the coating (5) on the at least one film roller (31).

17. The method according to claim 16, further comprising: The following steps are involved: a. Partial or complete reuse of the removed coating (5).

18. The method according to claim 16 or 17, in, The cleaning is performed by lateral movement or full cleaning.

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