A curtain coating mechanism for applying a treatment substance to at least one coating roll

Abstract

The invention relates to a device for applying a treatment substance, in particular starch or size, to a moving paper and board web (11), in particular to a containerboard or corrugated board, by means of at least one curtain coating mechanism (2.1, 2.2). In order to provide an improved treatment substance coating device, the at least one curtain coating die can be supplied with differently prepared treatment substances, and the curtain coater (2.1, 2.2) combines both a film mode of operation and a slot mode of operation by providing an electrically and / or mechanically drivable gap adjustment device (3.1, 3.2) for the outlet gap (14.1, 14.2) of the control die lip applied to the curtain coating die, and optionally sets the outlet gap (14.1, 14.2) to 100 μm to 500 μm in the film mode of operation or to 500 μm to 2.0 mm in the slot mode of operation, so that the at least one curtain coating mechanism (2.1, 2.2) is designed to be able to be operated in two different modes of operation.

Description

Technical Field

[0001] The present invention relates to an apparatus for applying a treatment substance, particularly starch, sizing agent or adhesive suspension, onto a moving paper web or paperboard web using liquid film technology. Background Technology

[0002] Recycled fibers are increasingly being used in the production of packaging paper and paperboard. For example, linerboard (TL) and corrugated paper (CM) in the European Union are primarily made from waste paper fibers. Due to the high proportion of recycled fibers, the strength properties of packaging paper are reduced. In papermaking, starch can be used to compensate for this loss of strength. Starch is usually added directly to the fiber suspension or sprayed onto the wet web surface in the wire section. Alternatively, starch can be applied to the paper web immediately downstream of the pre-drying unit using contact or non-contact coating methods.

[0003] As described, for example, in Chapter 10, Section 10.7.2, “Erzeugen von Papier,” of the 2nd edition of *Taschenbuch der Papiertechnik*, trough presses are used to coat starch onto packaging paper and paperboard. Most trough presses are equipped with two coating rolls. According to existing technology, the coating rolls are arranged at an angle of 0° to 15° relative to each other. During operation, the coating rolls close and form a pressing zone together with the paper web that is passing through. Starch or sizing solution is fed into the pressing zone through a so-called sizing tube. A pool is formed between each coating roll and the paper web. As the paper web is guided through the pool and through the pressing zone, the starch or sizing solution permeates into the paper. The coating weight of the starch or sizing solution is mainly determined by the liquid level in the pool, the residence time, the concentration of the liquid, and the pressure in the pressing zone. The temperature and viscosity of the liquid, as well as the porosity of the paper, also affect the permeation performance, thus affecting the coating weight.

[0004] The temperature for starch coating is typically between 50°C and 80°C. In a trough press, the typical solids content of the starch is between 5% and 12%, with a coating weight of 0.8 to 5.5 g / m² per side. 2 The linear pressure between the coating rolls varies between 40 and 100 kN / m. To achieve high penetration, the trough press operates within an upper linear pressure range of 80 to 100 kN / m. These high extrusion pressures in the pressure zone can be achieved using hard roll sleeves between 1 and 15 P&J (Pusey & Jones). Accordingly, hard roll sleeves are preferred for trough presses. Compared to film presses, trough presses offer the advantage of higher starch penetration into the paper.

[0005] However, due to the low solids content of starch, trough presses consume a lot of energy. This results in worse economics than, for example, with membrane presses. Therefore, paper manufacturers are always faced with the challenge of using the most economical process. Consequently, in facilities that produce linerboard and corrugated paper together, a combination of membrane / trough presses is typically used and operated accordingly, depending on the paper type.

[0006] To improve the technical and economic performance of membrane presses, new non-contact equipment and methods have been developed for coating starch using a curtain sizer (i.e., a curtain sizing machine), as described, for example, in patent documents DE20 2019 106 814 U1 and WO 2020 / 020626 A1. Accordingly, the measurement of the coating weight is achieved through volumetric flow control at the coating die itself. Compared to membrane presses, curtain sizing machines have a decisive advantage in that they are capable of coating starch with very high solids content, up to 25% and more.

[0007] Besides its advantages, curtain sizing machines also have technical limitations. They are limited in their application to low-viscosity starch. At viscosities below 30 mPa·s (solids content below 10%), the thin liquid film of starch becomes unstable upon contact with the coating rollers, interfering with the uniform distribution of the starch coating. Therefore, it is no longer possible to apply a uniform film as required in film press operation. However, to achieve high starch penetration into the paper, both low starch content and low viscosity are necessary. As already described, in these cases, supplying starch via a tank is better than supplying it via a membrane.

[0008] Both coating methods, namely tank coating and film coating, have their own limited operating ranges as different coating units. It is meaningful to use tank coating for low viscosity (below 20-30 mPa·s) or low solids content (below 10%), and to use film coating for high viscosity (above 30 mPa·s) and high solids content (above 10%). The prior art is described below using linerboard (TL) and corrugated paper (CM) types as examples.

[0009] Corrugated cardboard and boxboard are made from 100% waste paper fibers and have a unit area weight of 70 to 200 g / m². 2 The paper used in corrugated board production is the intermediate layer of the corrugations (or corrugations), while linerboard (TL) is used as the covering layer. The quality (grade) of the waste paper fibers used in the case of corrugated paper (CM) is higher than that used in the case of linerboard (TL).

[0010] Due to the different applications of linerboard and corrugated paper, the requirements for the properties of these products differ. For linerboard, surface gloss and hydrophobicity, as well as strength properties such as ring crush strength (RCT), short-pitch compression strength (SCT), and burst strength are important. For corrugated paper, surface gloss and hydrophobicity are not important, but strength properties such as burst strength, short-pitch compression strength (SCT), and especially flat crush strength (CMT) are very important.

[0011] Due to the aforementioned quality requirements, there are different objectives when surface-treating the two products with starch and sizing agents. For corrugated paper, it is necessary to maximize the penetration of starch into the paper, while for linerboard, surface treatment with both starch and sizing agents is important.

[0012] In the case of corrugated paper, the highest possible starch penetration is required to meet quality characteristics, while in the case of linerboard, the focus is on fixing the starch to the surface (see Kießler, B.: Verbesserung der Papier-festigkeiten und der Prozesssicherheit bei der vonWellpappenrohpapieren durch spezifischen PTS-ForschungsberichtIW 050275, Heidenau, 2006). Therefore, the starch solutions used for these two applications are prepared differently, allowing for targeted control of the depth of penetration into the paper.

[0013] Since deep penetration of starch is not required in the case of linerboard, the starch solution used in linerboard has a higher viscosity and correspondingly higher concentration (13-15%) compared to starch used for corrugated paper (5-12%). This is useful for economic reasons, as less energy is consumed in drying the paper with a higher solids content. Here, paper manufacturers aim to further increase the starch concentration. The concentration being limited to approximately 15% in the case of film presses was one of the main reasons for the development of curtain sizing machines for coating. Therefore, paper manufacturers face the challenge of adding additional coating units to their existing facilities.

[0014] The trough press and the curtain sizing machine are two separate units that must be arranged one after the other in the facility, similar to the blade coater on a coating machine. Typically, installing an additional coater requires extending the paper machine. Compromises must be made here in both mechanical manufacturing and production processes, often at the expense of paper quality. Summary of the Invention

[0015] Therefore, the technical problem to be solved by the present invention is to provide an apparatus for coating a treatment substance, especially starch or sizing agent, onto packaging paper and paperboard, especially corrugated paper (CM) and boxboard (TL), which improves the quality of the available paper / paperboard, and more specifically, improves the quality of the available paper / paperboard in the case of stable production.

[0016] This technical problem is solved by an apparatus for applying a treatment substance, particularly starch or sizing agent, onto a moving paper web and paperboard web, particularly linerboard or corrugated paper, via at least one curtain coating mechanism. The curtain coating mechanism has a curtain coating die for applying the treatment substance onto a coating roll, which forms a treatment pressure zone with a second roll in which the treatment substance is transferred from the coating roll to the corresponding side of the paper web and paperboard web. The curtain coating die also has a gap adjustment device for adjusting the exit gap. According to the invention, the at least one curtain coating die is capable of supplying different prepared treatment substances, and the gap adjustment device, which adjusts the exit gap of the curtain coating die to 100 μm to 500 μm for film-type operation and to 500 μm to 2.0 mm for trough-type operation, enables the at least one curtain coating mechanism to operate in these different operating modes.

[0017] This provides an apparatus for applying a treatment substance, comprising at least one curtain coating mechanism including a curtain coating die for applying a liquid film of the treatment substance, the liquid film automatically falling from a considerable height before colliding with a coating roller. The curtain coating mechanism combines both film-type and trough-type operating modes. The curtain coating mechanism according to the invention can optionally operate as a film press or a trough press and thus constitute a combined unit. Therefore, curtain coating can be performed using curtain coating dies operating in two different modes. Together, these two modes apply the treatment substance or run the paper web or paperboard web via liquid film technology.

[0018] A coating apparatus, particularly a curtain sizing machine, is achieved by providing an adjustment device for the outlet gap of the curtain coating die according to the invention, resulting in a design significantly different from known curtain coating apparatuses. Adjusting the gap from 500 μm to 2.0 mm achieves high curtain weight; however, due to the formation of a liquid pool above the roller pressing zone, curtain weight stability no longer directly determines coating quality. Capillary forces during the residence time in the pool and hydraulic pressure during passage through the pressing zone cause the treatment material to penetrate the web. The liquid level in the pool, influenced by the gap adjustment device according to the invention, together determines the absorption of the treatment material and thus the paper / paperboard quality.

[0019] Existing trough presses can be easily retrofitted into devices according to the invention, equipped with at least one coating mechanism according to the invention, with minimal cost. Furthermore, the coating method can be converted from film coating to trough operation without shutting down the paper machine. This eliminates the disadvantage that existing paper and paperboard machines typically offer limited flexibility for retrofitting / upgrading additional units, as such space is not provided.

[0020] Another design of the present invention can be derived from the following description. Attached Figure Description

[0021] The present invention will now be described in detail based on the embodiments shown in the accompanying drawings.

[0022] Figure 1 A schematic cross-sectional view of the apparatus for coating treatment materials according to the present invention is shown in membrane operation.

[0023] Figure 2 A schematic cross-sectional view of the apparatus for coating treatment materials according to the present invention is shown in tank operation.

[0024] Figure 3 A schematic cross-sectional view of a curtain coating die according to the present invention is shown, the curtain coating die having a gap adjustment device realized by an eccentric shaft.

[0025] Figure 4 A schematic cross-sectional view of a curtain coating die according to the invention is shown, the curtain coating die having a gap adjustment device implemented by a linear actuator. Detailed Implementation

[0026] This invention relates to an apparatus for applying a treatment substance, particularly starch, sizing agent, glue, or adhesive, onto a moving paper web and paperboard web 11, particularly linerboard or corrugated paper. The apparatus includes at least one curtain coating mechanism 2.1, 2.2 having a curtain coating die or slit for applying the treatment substance in the form of curtains 4.1, 4.2 onto at least one coating roller 6, 7. The curtains 4.1, 4.2 are preferably liquid films that fall freely from a considerable height onto the at least one coating roller 6, 7. The roller forces the coating liquid onto the paper web and paperboard web 11 through a pressure zone 15, which, together with a second roller 7, forms a treatment pressure zone or roller-type pressure zone 15. In the case of double-sided coating, the second roller is also designed as a coating roller. In the treatment pressure zone, the treatment substance is transferred from the coating rollers 6, 7 to the respective sides of the paper web and paperboard web 11. In pressure zone 15, the processing material or any other type of coating liquid is transferred from coating rollers 6, 7 to the corresponding side of the paper or paperboard web 11. Each of the curtain coating mechanisms 2.1, 2.2 also has a gap adjustment device 3.1, 3.2 for adjusting the outlet gap 14.1, 14.2 of the curtain coating die, which defines the nozzle of the curtain coating mechanism.

[0027] At least one curtain coating die can supply different processed materials. Furthermore, at least one curtain coating mechanism 2.1, 2.2 is designed to operate in different operating modes by means of gap adjustment devices 3.1, 3.2, which adjust the outlet gaps 14.1, 14.2 to 100 μm to 500 μm for film-type operation and to 500 μm to 2.0 mm for tank-type operation.

[0028] To technically realize the present invention, it is preferred that the curtain coating mechanisms 2.1, 2.2 be used in conjunction with coating rollers 5, 6, wherein at least one coating roller 7 may be designed as a bending-controlled roller. These rollers are known, for example, by the names S-roller, MHV-roller, or NIPCO-roller.

[0029] The rollers 6 and 7 used to form the roller pressing zone 15 can be equipped with a hard coating, such as ceramic or chromium, but can also be equipped with a hard sleeve made of polymer. Here, the surface hardness is less than 30 P&J, preferably less than 15 P&J. The coating rollers 6 and 7 can be temperature controlled.

[0030] Figure 1 An embodiment of the apparatus according to the invention is shown in a film-operated mode. Film operation is a coating system that precisely measures the amount of film that is transferred onto a web 11 in a roller gap 15 without a trough. The film-operated mode of the curtain coating mechanisms 2.1, 2.2 allows coating with very high starch solids content. Reference numeral 12 indicates possible lateral guidance for excess processing material.

[0031] The direction of travel of the paper web is from top to bottom and is indicated by an arrow. This is, for example, the coating of linerboard (TL). The starch solids content is relatively high, at 15%. Therefore, the volumetric flow rate used for this coating is relatively low. Cleaning blades 9.1 and 9.2 are arranged on the coating rolls 6 and 7 and are in the running position. During production, the coating rolls 6 and 7 are cleaned persistently with cleaning blades 9.1 and 9.2. Water spray nozzles or steam nozzles 10.1 and 10.2 may be provided for cleaning the coating rolls 6 and 7. The cleaning blades remove fibers and starch particles adhering to the roll surface from the rolls 6 and 7. Collection basins 8.1 and 8.2 prevent water droplets from falling onto the running paper web 11.

[0032] The curtain coating dies of curtain coating mechanisms 2.1 and 2.2 can be moved hydraulically or by electric motor. This allows for the specification of the entire unit's pivoting motion. In the event of a production interruption due to malfunction or fabric breakage, the nozzles and the entire unit of curtain coating mechanisms 2.1 and 2.2 can be moved to a ready position. In the holding position, starch preferably flows into collection basins 5.1 and 5.2 and is then returned from there to the workstation for reuse.

[0033] In operating mode, the curtain coating dies of the curtain coating mechanisms 2.1 and 2.2 are positioned such that, for example, the collision zones of the curtains 4.1 and 4.2 are aligned with the axes of the coating rollers 6 and 7. In this case, the angle α is between zero and 45°. This position of the curtain coating die is preferably chosen such that the distance of air boundary layer suction relative to the curtain is minimized. This prevents the boundary layer airflow from interfering with the curtain along the moving roller surface. In this position, a stable curtain can be produced without forming a heel (German: Fersenbildung) or undesirable backflow on the moving rollers 6 and 7. Below a positioning of approximately 45° α, the thin curtain is disturbed by the boundary layer airflow and can no longer make uniform contact with the roller surface.

[0034] The coating rollers 6 and 7 are preferably arranged at an angle of 0° to 15° relative to each other. The treatment material can be coated onto the coating rollers 6 and 7 first through curtains 4.1 and 4.2 on both sides. To form the curtains 4.1 and 4.2, a mold with an exit gap 14.1 and 14.2 of 100-500 μm is used.

[0035] The treatment material can be starch, sizing agent, or a mixture of these media. The treatment material is then conveyed onto the paper web or paperboard web 11 in the pressure zone 15 between coating rollers 6 and 7.

[0036] The corresponding curtains 4.1 and 4.2 can have a curtain height ranging from 50 to 300 mm between the collision point on the coating rollers 6 and 7 and the die exit. In this way, the liquid film on the curtains 4.1 and 4.2 will fall freely from a fairly high height and then collide with the coating rollers 6 and 7, applying a thin layer of liquid. At the same time, the coating rollers 6 and 7 rotate, transferring the coating liquid from here to the paper web or paperboard web 11 in the pressing zone 15.

[0037] like Figure 2 As shown, in the operation mode of the trough press, the processed material, especially starch or adhesive, can be first coated onto the coating roller through a coating die or directly guided into the tank 13. The curtain coating die can be positioned, for example, by linear guides 1.1 and 1.2.

[0038] Because the starch concentration is significantly lower in trough operation—that is, the processed material is prepared differently than in the membrane operation described above—the volumetric flow rate is correspondingly higher. Furthermore, trough operation requires an additionally higher volumetric flow rate to ensure a specific tank height. Therefore, the volumetric flow rate in trough operation can be, for example, 2 to 3 times higher than in the curtain sizing machine operation mode (membrane operation mode). With this high volumetric flow rate combined with a small nozzle outlet gap, the starch will flow out at very high velocities from nozzle gaps 14.1 and 14.2. These high outflow velocities may cause starch to splash and create turbulence when it collides with coating rollers 6 and 7 or the tank 13. This can interfere with the coating process.

[0039] To reduce the velocity of the flow from the nozzle, the outlet gaps 14.1 and 14.2 are adapted to the volumetric flow rate according to the present invention. The dimensions of the outlet gaps 14.1 and 14.2 of the coating die for trough operation mode are selected to be larger than those for curtain operation mode in film operation mode. According to the present invention, outlet gaps 14.1 and 14.2 of 0.5 mm to 2.0 mm have proven to be optimal for trough operation mode. To correct or adjust the outlet gaps 14.1 and 14.2, gap adjustment devices 3.1 and 3.2 are preferably provided on the nozzle lip of the curtain coating die of the curtain coating mechanism 2.1 and 2.2.

[0040] The nozzles of the curtain coating mechanisms 2.1 and 2.2 are positioned such that the angle α of the point of impact of the curtains 4.1 and 4.2 on the coating rollers 6 and 7 or the tank 13 is between 30° and 90°, preferably between 45° and 60°.

[0041] In the tank operation mode, it is preferable that the coating rollers 6 and 7 do not need to be cleaned, because rollers 6 and 7 are cleaned by the starch flow in the tank 13. The cleaning blades 9.1 and 9.2 are deflected.

[0042] Corrugated paper (CM) and boxboard (TL) are typically produced on the same paper machine. In this case, the paper type change is usually carried out without shutting down the paper machine. When the operating mode is changed trouble-free from film operation to trough operation, the curtain nozzles of the curtain coating units 2.1 and 2.2 and the entire unit can move toward the pressure zone 15.

[0043] Suppose that during ongoing production, a paper machine switches from producing boxboard (TL) to producing corrugated paper (CM). The process would be as follows:

[0044] When switching to trough press operation mode, starch continues to be applied to coating rollers 6 and 7 through curtain nozzles. The trough operation mode requires an additionally higher volumetric flow rate to adjust for the formation of a specific tank height. According to the invention, the nozzle outlet gaps 4.1 and 4.2 are widened for trough operation mode to accommodate the higher volumetric flow rate. Therefore, the nozzle outlet gaps 4.1 and 4.2 are adjusted from, for example, 350 μm to approximately 1 mm to switch the coating unit to trough operation mode. The adjustment of the outlet gaps 4.1 and 4.2 can be achieved manually or automatically (by electric motor or hydraulic system).

[0045] When using shaped rollers (German: Profilierungswalzen), the facility can also be operated in pure calender mode according to the present invention. For this purpose, the hard coating roller 6 should be equipped in such a way that it is possible to adjust to form a higher surface temperature (hot roller).

[0046] Figure 3 and Figure 4 For example, different embodiments of the gap adjustment devices 3.1 and 3.2 on the exit gap of the coating die are shown. Figure 3 The diagram shows gap adjustment devices 3.1 and 3.2 implemented by an adjuster acting on the die lip. This adjuster can be, for example, an eccentric shaft, a push rod, or a wedge. The adjuster can be electrically and / or mechanically actuated. Similarly, the nozzle gap can be adjusted, for example, by means of a linear actuator 3.3. The position of at least one curtain coating die relative to the coating roller can be changed such that the curtain height remains substantially the same in different operating modes.

[0047] The linear pressure in the roll pressing zone 15 can be between 20 kN / m and 200 kN / m, preferably between 80 kN / m and 120 kN / m. The paper web or paperboard web speed can be between 250 m / min and 2000 m / min, preferably between 600 m / min and 1800 m / min. The dry weight content of the paper web or paperboard web 11 can be selected to be greater than 90%, particularly between 92% and 98%. The unit volume flow rate of starch as the treatment substance in the trough operation can be between 15 l / (min*m) and 150 l / (min*m), and the unit volume flow rate in the film operation can be between 5 l / (min*m) and 50 l / (min*m). The solid content of starch as the treatment substance in the trough operation can be specified to be between 5% and 10%, and the solid content in the film operation can be between 10% and 25%. The viscosity of starch as the treatment substance can be selected to be between 20 mPas and 200 mPas. The temperature for processing starch can be selected between 50°C and 110°C, preferably between 70°C and 100°C.

[0048] After a thorough description of the invention, those skilled in the art will find that many changes and modifications can be made to the invention without departing from the spirit or scope of the appended claims. In particular, the groove mold mode can also be based on the sliding mold mode.

Claims

1. An apparatus for applying a treatment substance onto a moving paper web and paperboard web (11) via at least one curtain coating mechanism (2.1, 2.2), the curtain coating mechanism having curtain coating nozzles for applying the treatment substance onto coating rolls, wherein a first coating roll (6) and a second coating roll (7) of the coating rolls form a treatment pressure zone (15) in which the treatment substance is transferred from the coating rolls to corresponding sides of the paper web and paperboard web (11), and the curtain coating nozzles having gap adjustment devices (3.1, 3.2) for adjusting the exit gaps (14.1, 14.2), characterized in that, The at least one curtain coating nozzle is capable of supplying different prepared treatment materials, and the curtain coating mechanism (2.1, 2.2) adjusts the outlet gap (14.1, 14.2) of the curtain coating nozzle by providing an electrically and / or mechanically driven gap adjustment device (3.1, 3.2), which acts on the nozzle lip and alternately sets the outlet gap (14.1, 14.2) to 100 μm to 500 μm in film operation mode or to 500 μm to 2.0 mm in trough operation mode, such that the at least one curtain coating mechanism (2.1, 2.2) is designed to operate in two different operating modes, wherein the angle α of the point of impact of the curtain on the first coating roller (6) relative to the vertical line is selected to be between 0° and 45° in film operation and between 30° and 90° in trough operation.

2. The device according to claim 1, characterized in that, It is provided with an adjuster that can be electrically and / or mechanically operated to achieve a gap adjustment device (3.1, 3.2) for the outlet gap (14.1, 14.2) of the curtain coating nozzle.

3. The device according to claim 1 or 2, characterized in that, The position of at least one curtain-type coating nozzle relative to the coating roller can be changed.

4. The device according to claim 3, characterized in that, The position of the at least one curtain coating nozzle relative to the coating roller can be changed such that the curtain height remains substantially the same in the different operating modes.

5. The device according to claim 1 or 2, characterized in that, At least the second coating roller (7) is designed as a bending compensation roller.

6. The device according to claim 1 or 2, characterized in that, At least one of the coating rollers has a diameter between 1000 and 1800 mm.

7. The device according to claim 1 or 2, characterized in that, The hardness of the sleeve of the first coating roller (6) is selected in the range of 0 to 5 P&J.

8. The device according to claim 1 or 2, characterized in that, The second coating roller (7) is designed as a bending compensation roller with 5 to 30 P&J.

9. The device according to claim 1 or 2, characterized in that, An overflow funnel (12) is provided at each edge of the edge region of the at least one curtain coating nozzle, the overflow funnel being constructed on the side of the processing pressure zone (15).

10. The device according to claim 1 or 2, characterized in that, The linear pressure in the treatment zone (15) is between 20 kN / m and 200 kN / m.

11. The device according to claim 1 or 2, characterized in that, The speed of the paper web or paperboard web (11) is between 250 m / min and 2000 m / min.

12. The device according to claim 1 or 2, characterized in that, The dry weight content of the paper web or paperboard web (11) is selected to be greater than 90%.

13. The device according to claim 1 or 2, characterized in that, The volumetric flow rate of starch as the treatment material is between 15 l / (min*m) and 150 l / (min*m) in tank operation and between 5 l / (min*m) and 50 l / (min*m) in membrane operation.

14. The device according to claim 1 or 2, characterized in that, The starch used as a processing material has a solids content between 5% and 12% in tank operation and between 10% and 25% in membrane operation.

15. The device according to claim 1 or 2, characterized in that, The viscosity of the starch used as the treatment material was selected to be between 20 mPas and 200 mPas.

16. The device according to claim 1 or 2, characterized in that, The temperature for processing starch is selected to be between 50°C and 110°C.

17. The device according to claim 1 or 2, characterized in that, The angle α of the point of impact of the curtain on at least one coating roller relative to the vertical line is selected to be between 0° and 15° in film operation and between 45° and 60° in trough operation.

18. The device according to claim 17, characterized in that, The curtain-type coating nozzle and its spray lip can be positioned via a control device to change the operating mode during production.

19. The device according to claim 1, characterized in that, The processing substance is starch or sizing agent, and the paperboard web (11) is boxboard or corrugated paper.

20. The device according to claim 6, characterized in that, At least one coating roller has a diameter between 1200 mm and 1600 mm.

21. The device according to claim 7, characterized in that, The hardness of the sleeve of the first coating roller (6) is selected in the range of 0 to 1 P&J.

22. The device according to claim 8, characterized in that, The second coating roller (7) is designed as a bending compensation roller with 0 to 10 P&J.

23. The device according to claim 10, characterized in that, The linear pressure in the treatment zone (15) is between 80 kN / m and 120 kN / m.

24. The device according to claim 11, characterized in that, The speed of the paper web or paperboard web (11) is between 600 m / min and 1800 m / min.

25. The device according to claim 12, characterized in that, The dry weight content of the paper web or paperboard web (11) is selected to be between 92% and 98%.

26. The device according to claim 16, characterized in that, The temperature for processing starch is chosen to be between 70°C and 100°C.

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