Apparatus and method for coating and curing a polymer layer on a cylindrical body - Patent Application 20070122997

Abstract

The present invention relates to a layer production system for producing a polymer layer on a cylindrical substrate (1), and includes a coating device (2) for coating the cylindrical substrate (1) with a fluid polymer to produce a fluid polymer layer, a curing device (20) for curing the fluid polymer layer on the substrate (1), a substrate receiving area for supporting the cylindrical substrate, a coating translation device for translating the coating device (2) relative to the substrate (1) in the longitudinal direction (X) of the substrate (1), a curing translation device for translating the curing device (20) relative to the substrate in the longitudinal direction (X) of the substrate, a rotation device for rotating the substrate (1) supported in the substrate receiving area in a rotation direction (R), and a movement control device for controlling operation by combining the movement of these two translation devices and the movement of the rotation device.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION The present invention relates to an apparatus and method for producing a polymer layer on a cylindrical substrate, and in particular to an apparatus and method for coating and curing such a polymer layer on a substrate. [Background technology]

[0002] Such a substrate is, for example, a printing plate which may be coated with a polymeric coating material. In the following text, the terms "substrate" or "printing plate" are used in particular as a general term for a gravure printing plate, a letterpress printing plate or an embossing patterning plate, but also for a coating roller or an inking roller.

[0003] WO 2014 / 066760 A1 relates to an apparatus and method for coating a medical device. The medical device may be, for example, a balloon catheter coated with a drug.

[0004] WO 2021 / 052641 A1 discloses a printing plate and a polymeric coating material therefor. The coating material is a polymer nanocomposite that can be coated onto the printing plate in a single layer. The polymer nanocomposite is coated onto the cylindrical outer surface of the printing plate in a fluid state and then cured by irradiation with UV light. The resulting polymer layer can be patterned with the aid of an infrared laser to create a surface pattern with cells or patterns for ink absorption or embossing, as also described in WO 2021 / 052641 A1.

[0005] Coating and curing flowable polymers, such as the nanocomposites mentioned above, takes time. Curing must be achieved using UV light, among other things. To achieve an efficient, low-emission, i.e., ozone-free, curing process, UV LEDs are increasingly being used, which rely on surface passivation due to oxygen inhibition, which is common in radical polymerization surfaces.

[0006] When the cylindrical substrate is a printing cylinder such as a gravure cylinder, the surface quality of the polymer coating has a direct impact on the print quality, so the required quality is high: unevenness on the polymer surface will result in a poor printed image.

[0007] Therefore, a high degree of precision is required in coating the polymer onto the substrate to produce a polymer layer of suitable quality.

[0008] This is particularly true when coating a polymer layer onto a printing plate such as a gravure cylinder, as the quality of the polymer layer also influences the quality of the subsequent print, while the coating must be applied efficiently and cost-effectively for use in, for example, a print shop.

[0009] This also applies to the process of curing the polymer after the coating process: it must be possible to cure efficiently and quickly.

[0010] SUMMARY OF THE INVENTION Accordingly, the present invention aims to define a layer production system for producing a polymer layer on a cylindrical substrate, which allows a flowable polymer to be coated onto the substrate and subsequently cured.

[0011] The object according to the invention is achieved by a layer production system having the features of claim 1. A method for producing a cured polymer layer is defined in the independent claim. Advantageous configurations are specified in the dependent claims.

[0012] A layer manufacturing system for manufacturing a polymer layer on a cylindrical substrate is defined, comprising a coating device for coating the cylindrical substrate with a flowable polymer and manufacturing a flowable polymer layer, a curing device for curing the flowable polymer layer on the substrate, a substrate receptacle for carrying the cylindrical substrate, a coating translation device for causing translational movement of the coating device relative to the substrate in the longitudinal direction of the substrate, a curing translation device for causing translational movement of the curing device relative to the substrate in the longitudinal direction of the substrate, a rotation device for rotating the substrate carried in the substrate receptacle in a rotational direction, and a motion control unit designed to control the movements performed by the two translation devices and the movements caused by the rotation device.

[0013] In particular, the control allows for a helical motion of the coating or curing device relative to the substrate surface.

[0014] In this layer-forming system, it is possible to first coat the curved surface area of ​​the substrate with a polymer layer, by moving the coating device relative to the surface of the substrate in a spiral path.

[0015] After the polymer is coated, curing is performed by a curing device that also moves in a spiral path relative to the surface of the substrate. This process does not require the substrate to be re-clamped. Rather, the substrate can remain in the substrate receptacle, which rotates the substrate throughout the coating and subsequent curing steps.

[0016] The coating and curing devices move only in the longitudinal or translational direction, and each functional head (the nozzle for coating the fluid polymer in the coating device and the UV irradiation device in the curing device) can also be moved in terms of distance from the substrate or polymer surface, i.e., in the radial direction of the substrate, as will be explained later.

[0017] Thus, the coating device can be moved relative to the rotating substrate. In particular, the translation direction can be, for example, the longitudinal direction of the substrate, i.e., the central axis of the substrate, while the substrate itself is rotated around its main or central axis. The desired relative helical motion is achieved by combining the rotation of the substrate with the translation of the coating device. This allows the flowable material to be evenly coated on the surface of the substrate. In this process, a helical path is formed, and the path elements are arranged adjacent to each other without any gaps. Any remaining small gaps can then be easily closed by the action of a blade, such as a smoothing blade, as described below. Ideally, the helical motion is precisely set so that there are essentially no gaps between adjacent layers.

[0018] Thus, the curing device for curing the polymer can also be moved relative to the rotating substrate. In particular, the translation direction can be, for example, the longitudinal direction of the substrate, i.e., its central axis, while the substrate itself rotates around its main or central axis. The desired relative helical motion is achieved by a combined rotation of the substrate and translation of the curing device. This allows for uniform curing of the polymer on the substrate surface. In particular, the resulting helical path of the ultraviolet light allows for effective, gap-free curing of the polymer.

[0019] The coating device has a supply nozzle for coating a material onto a substrate, a smoothing blade arranged downstream of the supply nozzle and designed to smooth the surface of the material coated on the substrate, and a force generating device for applying a force to the smoothing blade, wherein the force that can be applied to the smoothing blade by the force generating device is variable, and the force generating device can have a force control unit for setting the force that can be applied to the smoothing blade by the force generating device.

[0020] The cylindrical substrate to be coated can be any kind of roller, in particular a printing plate, such as a gravure plate or gravure cylinder, a patterning plate or patterning cylinder, an embossing plate or embossing cylinder, and also a letterpress plate or letterpress cylinder, or a coating roller, and also an inking roller, for example for flexographic printing.

[0021] The flowable material may in particular be a flowable polymeric material.

[0022] It may be, for example, a polymer coating material as described in WO 2021 / 052641 A1. In particular, the polymer may be a coating material for coating a printing plate, comprising a liquid starting material that is polymerizable by UV light to form a polymer matrix and a filler having a sub-microscale size, wherein the coating material comprises an additional filler in addition to the sub-microscale filler. Here, the sub-microscale filler is in the form of particles and has a size ranging between 100 nm and 999 nm. Here, the additional filler is a nanoscale filler having filler particles with a nanoscale size ranging between 1 nm and 99 nm. The sub-microscale filler may be a metal oxide-coated mica, TiO (2) or (Sn,Sb)O (2 ) and the nanoscale filler is composed of at least one metal oxide and / or semi-metal oxide selected from Al (2) O (3) , SiO (2) , TiO (2) , ZrO (2) The sub-microscale fillers may be covalently integrated into the polymer matrix of the starting material, and may be metal oxides and / or semi-metal oxides selected from organometallic particles. Nanoscale fillers may be covalently integrated into the polymer matrix of the starting material and may be included to enhance wear resistance. The sub-microscale fillers in the starting material may result in higher absorption of IR radiation than without the filler.

[0023] The smoothing blade is positioned downstream of the delivery nozzle and is suitable for smoothing the layer of material coated on the substrate, particularly for sealing cracks and gaps formed between adjacent layers of material as the material is coated.

[0024] For this purpose, the smoothing blade is pressed against the material layer by a force generator, and the contact pressure is adjusted to the ideal pressure. If the contact pressure is too high, the layer thickness distribution will change significantly, while if the contact pressure is too low, the transition gap between adjacent layers will not close. Different viscosities, surface tensions, and other material variables require different surface pressures to be applied by the smoothing blade.

[0025] The smoothing blade can be made of a thin plastic sheet that can be deformed in an appropriate manner to fit the surface of the material to be smoothed.

[0026] The force generator is designed to deflect and deform the smoothing blade from a rest position, which at this point is the initial position. The force generator and a force control unit coupled thereto allow the force applied by the force generator to the smoothing blade to be precisely set so that the smoothing blade is pressed against the material to be smoothed with the appropriate force.

[0027] The layer thickness of the material may be, for example, a target layer thickness of 10 to 500 μm, in particular 10 to 250 μm, with the deviation from the target layer thickness preferably being minimal, for example within a range of maximum ±5% or maximum ±3%.

[0028] The curing device may include a UV illuminator for generating UV light and supplying the UV light to the light opening, a curing gap disposed in front of the light opening, an inert gas supply device for supplying inert gas to the curing gap above the light opening, an inert gas flow through the curing gap, and an oxygen measuring device for measuring the oxygen content in the inert gas downstream of the light opening.

[0029] The polymer material is coated onto the outer surface of the substrate in a suitable manner prior to the curing step and remains fluid in this state, i.e., before curing.

[0030] The UV illuminator generates UV light that exits through a light aperture, from which it can be directly irradiated onto the polymer layer to be cured on the substrate. For this purpose, a curing gap is positioned in front of the light aperture, forming a narrow, inert irradiation channel. The formation of the curing gap or channel is ensured by precise positioning of the curing device relative to the polymer surface (and thus the substrate surface), as will be explained later.

[0031] The curing gap is at least partially open toward the polymer layer to be cured. In particular, the curing gap has at least a partial opening on the side facing the substrate. The curing gap has a gas inlet for introducing an inert gas and a gas outlet for discharging the inert gas. Within the curing gap, a light opening is positioned opposite the polymer layer to perform curing of the polymer layer by irradiation with UV light.

[0032] The oxygen measuring device serves to measure the oxygen content of the inert gas discharged from the optical aperture. This process, in particular, measures the amount of residual oxygen in the inert gas. To achieve the desired protective effect of the inert gas on the polymer layer, the inert gas must be at a specific concentration, which can be indirectly detected by measuring the residual oxygen content in the inert gas flow. For this purpose, the oxygen measuring device may include a λ probe. Based on the residual oxygen measurement result, the required amount of inert gas is set and supplied to the upstream end via the inert gas supply device. This ensures that sufficient inert gas is always supplied to the curing gap during UV irradiation. Meanwhile, excessive consumption of inert gas can be prevented, enabling economical and resource-saving curing.

[0033] As the inert gas, nitrogen is particularly suitable as it provides a sufficient inert effect.

[0034] This curing device allows the polymer layer to be cured regardless of the shape or format of the cylindrical substrate.

[0035] As noted above, the coating device and, optionally, the curing device, can move longitudinally along the curved region of the cylindrical substrate, parallel to the major axis of the substrate.

[0036] The coating device and / or curing device can each perform a helical motion relative to the substrate. This is because the substrate can be rotated in a rotational direction while the coating device and curing device perform a translational motion along the longitudinal direction of the substrate. The resulting relative motion corresponds to a helical motion. This helical motion allows both the coating device, when coating the flowable polymer, and the curing device, when curing the polymer layer formed on the substrate, to conform to the desired cylindrical surface of the substrate.

[0037] A coating positioning device for the coating device may be provided for positioning the coating device relative to the substrate in a radial direction of the substrate.

[0038] The coating positioning device may have a distance adjusting device, which may have a distance measuring device for measuring the distance between the coating device and the substrate, and may further have a distance setting device for setting the distance of the coating device relative to the substrate so that the distance corresponds to a predetermined value.

[0039] Distance measurements can be inductive, capacitive, or laser-assisted, and the distance can be variably adjusted with mechanical precision. In this respect, the distance measuring device is a distance sensor.

[0040] Additionally, the curing device may be provided with a curing positioning device for positioning the UV lighting device.

[0041] The curing positioning device, like the coating positioning device, may have a distance adjusting device, which may have a distance measuring device for measuring the distance between the curing device and the substrate, and may further have a distance setting device for setting the distance of the curing device relative to the substrate to correspond to a predetermined value.

[0042] The distance measurement of the curing device can be inductive, capacitive or laser-assisted, and the distance can be variably adjusted with mechanical precision. In this case, the distance measuring device also serves as a distance sensor.

[0043] The method for producing a polymer layer on a cylindrical substrate comprises: coating a cylindrical substrate with a flowable polymer to form a flowable polymer layer; curing the flowable polymer layer on the substrate; securing a cylindrical substrate to a substrate receptacle; translating the coating device relative to the substrate in the longitudinal direction of the substrate during coating; translating the curing device relative to the substrate in a longitudinal direction of the substrate during curing; rotating the substrate contained within the substrate receptacle in a rotational direction during coating and curing; It involves coordinating two translational movements and a rotational movement of the substrate.

[0044] During coating of the cylindrical substrate and curing of the polymer layer, the substrate needs to be held in a suitable manner in the substrate receptacle so that the substrate surface is easily accessible.

[0045] These and further features and advantages of the present invention are explained in more detail below on the basis of examples and with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0046] [Figure 1] Diagram showing a coating system for coating a polymer layer onto a cylindrical substrate. [Figure 2] Figure 1. Diagram showing a coating apparatus for coating a polymer onto a cylindrical substrate as part of a coating system. [Figure 3] FIG. 3 is a cross-sectional side view of the device of FIG. 2. [Figure 4] FIG. 3 is a diagram showing details of part “C” in FIG. 2. [Figure 5] FIG. 1 illustrates a curing system for curing a polymer layer on a cylindrical substrate. [Figure 6] 6 shows a curing device as part of the curing system of FIG. 5. [Figure 7] 7 is a detailed enlarged view of the curing device of FIG. 6. [Figure 8] FIG. 7 is a cross-sectional partial side view of the curing apparatus of FIG. 6.

[0047] FIG. 1 is a perspective view of a coating system as part of a layer production system for producing polymer layers on a cylindrical substrate 1 .

[0048] In the illustrated example, the substrate 1 is a printing plate, i.e., a gravure cylinder used in gravure printing. The gravure cylinder is coated with a flowable polymer. This can be, for example, a nanocomposite as known from WO 2021 / 052641 A1. The polymer coating of the gravure cylinder is suitable for forming small depressions, so-called cells, by laser treatment, in particular with a near-infrared laser (NIR). The near-infrared laser (NIR) absorbs the printing ink and allows it to be transferred to the printing object. For this, the polymer layer must have a relatively small thickness (layer thickness), for example, between 10 μm and 500 μm, in particular between 10 μm and 250 μm.

[0049] The substrate 1 or the gravure cylinder is held so as to be rotatable in a rotation direction R in a receptacle (not shown).

[0050] A coating device 2 is provided on the outer surface of the substrate 1, and is movable in a translation direction X along the outer surface of the substrate 1. The coating device 2 serves to coat the cylindrical curved surface region of the substrate 1 with a flowable polymer material.

[0051] The translational movement of the coating device 2 in the X direction and the rotation of the substrate 1 in the R direction are superimposed, causing the coating device 2 to perform a relative spiral motion relative to the outer surface of the substrate 1, as shown by the arrow S in Figure 1. This allows the coating device 2 to coat the outer surface of the substrate 1 with a flowable polymer material, e.g., a width of several millimeters, e.g., 5 mm to 30 mm. This relative spiral motion allows one polymer layer to be coated helically or spirally next to another polymer layer, ultimately resulting in a uniform coating of the entire curved surface of the substrate or a portion thereof. With the aid of a smoothing element, as described later, gaps that arise between adjacent polymer layers during this process can be uniformly filled to form a uniform, homogeneous polymer layer.

[0052] To coat the polymer material, the coating device 2 must maintain a uniform, very close distance to the substrate surface. For this purpose, the coating device 2 can be moved in the radial direction Z of the substrate 1 by a coating positioning device (not shown). For this purpose, the coating positioning device can have a distance adjustment device with a distance measuring device 3. Depending on the design, the distance measuring device 3 can operate as an inductive, capacitive, or laser-assisted distance sensor to support the distance adjustment.

[0053] 2 to 4 show the coating apparatus 2 in detail. Fig. 2 shows the main part, Fig. 3 is a cross-sectional side view of Fig. 2, and Fig. 4 is a detailed enlarged view of part C of Fig. 2.

[0054] The coating device 2 comprises a carrier body 5. A supply nozzle 6 is fixed to the carrier body 5, to which the coating material 7 is supplied in the form of a flowable polymer material. The coating material 7 is transported and supplied continuously, vibration-free and precisely by means of, for example, a syringe pump or an eccentric screw pump (dispenser).

[0055] The feed nozzle 6 has a cylindrical material supply portion 8 which tapers conically to an exit opening 9. The exit opening 9 may have a depth T of, for example, 1-3 mm and a width B of 5-30 mm, although other dimensions are also possible.

[0056] Additionally, the delivery nozzle 6 may be tapered at a taper angle towards the outlet opening 9 (material outlet). For example, a taper angle α of 1° to 7° will result in laminar flow and increase the flow velocity of the coating material 7 just before the material is discharged.

[0057] A distance from the delivery nozzle 6, in particular the outlet opening 9 of the delivery nozzle 6, to the substrate 1 in the range of 1×S to 4×S results in a sufficiently large meniscus or a sufficiently large heel at the nozzle outlet, so that the entire nozzle width is completely filled with flowable material, where S is the desired layer thickness on the substrate 1. A constant distance results in a constant layer thickness.

[0058] As seen from the downstream side in the direction of rotation of the supply nozzle 6, a smoothing blade 10 is fixed to the carrier body 5 in order to smooth the surface of the polymer material coated on the substrate 1. The smoothing blade 10 is, for example, a plastic sheet. The plastic surface of the smoothing blade 10 is suitable for achieving the desired surface quality of the smoothed polymer.

[0059] A support blade 11 is arranged on the rear side of the smoothing blade 10 over the entire rear surface of the smoothing blade 10. The support blade 11 may be made of spring steel and therefore supports the shape of the smoothing blade 10 and ensures that the smoothing blade 10 applies a sufficiently high pressure to the polymer being smoothed or spread.

[0060] FIG. 4 is an enlarged view of the smooth blade 10 and the support blade 11.

[0061] A reset blade 12, also made of steel or spring steel, is provided in front of the smooth blade 10 and extends across part of the surface of the smooth blade 10 (FIG. 4). For example, the reset blade 12 may extend over half or one-third of the surface of the smooth blade 10.

[0062] The blades 10, 11, 12 are fixed laterally to blade fixing portions 13 provided on the carrier body 5.

[0063] A pressure piston 14 is provided on the rear side of the smoothing blade 10, and this pressure piston 14 is actuated and moved by a pneumatic cylinder 15, which is controlled with compressed air via an air pressure supply device 16. The compressed air in the pneumatic cylinder 15 is used to press the pressure piston 14 downward against the support blade 11 and thus the smoothing blade 10, thereby pressing the support blade 11 together with the smoothing blade 10 against the reset blade 12. The reset blade 12 exerts a counterforce against the action of the pressure piston 14, so that a force balance is established depending on the applied air pressure. This makes it possible to accurately set the contact pressure of the smoothing blade 10 against the polymer material to be smoothed.

[0064] The contact pressure of the smoothing blade 10 on the polymer layer can be set using an adjustment unit. Too high a contact pressure will result in a large change in the layer thickness distribution, while too low a contact pressure will prevent the transition gaps between the individual spiral coatings from closing. Due to different viscosities, surface tensions, and other material variables, the surface pressure of the smoothing blade 10 on the polymer material must be variable.

[0065] The width of the smoothing blade 10 may be 2 to 3 times, or 5 to 10 times the width of the spiral layer to ensure a large support surface and uniform layer homogenization.

[0066] Figure 5 shows a curing system as an additional part of a layer production system for producing a polymer layer on a cylindrical substrate. In particular, the components shown in Figure 5 complement the components shown in Figure 1, so that the overall layer production system combines the components of Figures 1 and 5, i.e., first coating a layer of a flowable polymer on substrate 1 and then curing the polymer layer on substrate 1.

[0067] Thus, in the curing system of Figure 5, it is assumed that the substrate 1 is already covered with a flowable polymer layer, which must be cured in order to be dimensionally stable and able to serve its practical purpose, e.g., as a gravure roller.

[0068] A substrate 1, for example a gravure roller, is held in a receptacle, also not shown, and rotated in a rotational direction R, similar to the system of FIG.

[0069] A curing device 20 is disposed around the periphery of the substrate 1, and uses ultraviolet light to cure the polymer layer.

[0070] 1 and 5, the entire layer manufacturing system includes the coating device 2 and the curing device 20 shown in FIG. 1. That is, a polymer layer can be first coated on the curved area of ​​the substrate 1 by the coating device 2, and then cured by the curing device 20 through ultraviolet radiation. In both steps, the substrate 1 can be rotated about its main or longitudinal axis, and the coating device 2 and the curing device 2 can be moved along the curved area.

[0071] When using LEDs to UV-cure polymers, there is a risk that the free radicals of the photopolymerization initiator released by the LED's UVA radiation will combine with oxygen in the air, preventing complete curing of the surface. For this reason, UV irradiation must be carried out in an inert gas atmosphere. For this reason, the curing device 20 is equipped not only with a UV irradiation device 21 but also with an inert gas supply device 22.

[0072] 1, the curing device 20 also includes a curing translation device (not shown) that allows the curing device 20 to move in a translation direction X along the longitudinal axis of the substrate 1. Similarly, the substrate rotates in a rotation direction R, resulting in a helical movement S. In this way, the curing device 20, equipped with the UV illumination device 21, can cover the entire surface of the polymer layer coated on the curved area of ​​the substrate 1 and thus cure the polymer.

[0073] Like the coating device 2 described above, the curing device 20 also comprises a curing positioning device (not shown) with a distance adjustment device for setting the position of the curing device 20 relative to direction Z, i.e. the direction of the surface of the substrate 1 (radial direction of the substrate 1). For this purpose, a distance measuring device 23 is further provided. It is important to maintain the distance accurately in order to obtain satisfactory curing results.

[0074] 6 is an enlarged cross-sectional view of the curing device 20. The curing device 20 is depicted for two substrates 1a, 1b of different sizes. In this way, the curing device 20 can be used for substrates 1 having significantly different diameters.

[0075] The curing device 20 has a UV lighting device 21 located approximately in the center, which is arranged vertically in the illustrated example, and at its bottom, as will be described later, is able to emit UV light through a light opening 21a (FIG. 7).

[0076] The inert gas supply device 22, located to the right of the UV illumination device 21 in Fig. 6, includes a gas supply line 24 through which an inert gas is supplied from a storage tank, such as a gas cylinder or gas tank. Nitrogen is particularly preferred as the inert gas. The flow rate of the inert gas to the optical opening 21a of the ultraviolet illumination device 21 is adjusted by a mass flow adjustment unit 25, which will be described in detail later.

[0077] 7 shows an enlarged view of the lower part of the UV illumination device 21 compared to FIG. 6. The light opening 21a, which functions as the exit opening of the UV illumination device 21 and through which UV light for irradiating the polymer material is emitted, is covered with a UV light-transmitting quartz glass cover 26.

[0078] The curing gap 27 is formed between the UV illuminator 21 or the quartz glass cover 26 and the polymer layer-covered surface of the substrate 1, which is located a short distance away. Above the quartz glass cover 26 and the curing gap 27, the inert gas supply device 22 has a flushing nozzle 28, through which an inert gas can be introduced from a gas inlet 29 into the curing gap 27. As shown in FIG. 8, the flushing nozzle 28 is located at the tip of a flushing funnel 30 to which a flushing flow path 31 is connected.

[0079] FIG. 8 shows a cross section through the flushing channel 31 of FIG. 7. It clearly shows that the inert gas supplied from the mass flow control unit 25 via the gas line 32 is turbulent in the flushing funnel 30 and then calms down within the narrow flushing channel 31. The inert gas flow is essentially laminarized within the flushing channel 31, which also functions as a calming section, allowing the inert gas to be discharged across the entire width of the flushing nozzle 28. During this process, the polymer material on the substrates 1a and 1b is covered with inert gas before it reaches the optical opening 21a of the quartz glass cover 26 within the curing gap 27 where UV illumination occurs, thereby protecting the polymer material.

[0080] After being ejected from the flushing nozzle 28, the inert gas is expected to partially mix with atmospheric oxygen because the area of ​​the gas inlet 29 into the curing gap 27 cannot be completely sealed from the environment. Therefore, the curing gap 27 does not pass through pure inert gas, but rather a mixture of inert gas and residual oxygen. The sealing measures taken to reduce the intrusion of ambient air and the measures taken to ensure a predetermined proportion of inert gas in the mixture are described below.

[0081] Downstream of the quartz glass cover 26 or the curing gap 27, i.e., after UV irradiation, the curing gap 27 terminates in a gas outlet 33. A gas outlet 34 is provided therein, which has a downstream measuring chamber 35. The gas outlet 34 can be specifically designed as a gap, establishing a communication path from the end of the curing gap 27 (gas outlet 33) to the measuring chamber 35. Thus, part of the inert gas is discharged via the gas outlet 34 or into the measuring chamber 35, while another part of the inert gas not captured by the gas outlet 34 can escape into the environment.

[0082] To reduce leakage or loss of the inert gas into the environment, the hardening gap 27 is sealed on all sides, i.e. on all four sides, by contactless seals specially designed in the form of blade seals 36. The blade seals 36 are arranged in a staggered arrangement and comprise one or more sheet metal elements that act as flow obstacles to prevent the inert gas from flowing outwards. In this way, in combination with the gas conveying device described below, it is possible to ensure that only a relatively small portion of the inert gas escapes into the environment, while the other portion is removed via the measurement chamber.

[0083] The measuring chamber 35 is equipped with a λ probe 37 as part of an oxygen measuring device. This oxygen measuring device can be used to measure the (residual) oxygen content of the inert gas downstream of the UV irradiation point at the optical opening 21a. In this way, the inlet gas flow rate or the ratio of inert gas to oxygen can be adjusted using the mass flow control unit 25 to maintain the residual oxygen content and the inert gas content within a predetermined range and ensure effective protection against oxidation of the polymer surface during UV irradiation. Here, a residual oxygen content of 0.1% to 10%, especially 0.5% to 5%, has proven to be desirable depending on the curing behavior of the polymer mixture.

[0084] The inert gas flow is generated by a gas conveying device 38 having an extraction fan 39. The extraction fan 39 creates a vacuum, and the mixed gas is extracted from the inert gas supply device 22 through the hardening gap 27. The gas thus flows through the gas supply line 24, the mass flow control unit 25, the gas line 32, the flushing funnel 30, the flushing nozzle 28, the hardening gap 27, the gas ejector 34, the measuring chamber 35, and the extraction fan 39.

Claims

1. A layer production system for producing a polymer layer on a cylindrical substrate (1), said system comprising: a coating device (2) for coating the cylindrical substrate (1) with a fluid polymer to form a fluid polymer layer; a curing device (20) for curing the flowable polymer layer on the substrate (1); a substrate receptacle for supporting the cylindrical substrate; a coating translation device for generating a translational movement of the coating device (2) relative to the substrate (1) in the longitudinal direction (X) of the substrate; a curing translation device for generating a translational movement of the curing device (20) relative to the substrate in the longitudinal direction (X) of the substrate; a rotation device that rotates the substrate (1) accommodated in the substrate receptacle in a rotation direction (R); Controlling the movements performed by the two translational devices and the movements performed by the rotational device and a motion control unit designed to:

2. The coating device (2) comprises: a supply nozzle (6) for coating the substrate (1) with a material; a smoothing blade (10) disposed downstream of the supply nozzle (6) for smoothing the surface of the material coated on the substrate (1); and a force generating device (14, 15) for applying a force to the smoothing blade (10), The force applied by the force generating device (14, 15) to the smoothing blade (10) is variable; 2. The layer manufacturing system according to claim 1, wherein the force generating devices (14, 15) comprise a force control unit for setting the force applied by the force generating devices to the smoothing blade (10).

3. The curing device (20) is a layer production system according to claim 1 or 2: a UV lighting device (21) for generating UV light and supplying said UV light to a light opening (21 a); a curing gap (27) located in front of the light opening; an inert gas supply device (22) for supplying an inert gas to the curing gap (27) upstream of the light opening (21 a); a flow of inert gas through said curing gap (27); 3. A layer production system according to claim 1 or 2, further comprising an oxygen measuring device (37) for measuring the oxygen content in the inert gas downstream of the optical opening (21a).

4. 10. A layer production system according to any one of the preceding claims, wherein a combination of the translational movement of the coating device (2) and / or the curing device (20) and the rotational movement of the substrate (1) in each case results in a helical movement (S) as relative movement.

5. 10. A layer production system according to any one of the preceding claims, wherein the coating device (2) and / or the curing device (20) each perform a helical movement (S) relative to the substrate (1).

6. 10. A layer manufacturing system according to any one of the preceding claims, wherein a coating positioning device is provided for the coating device (2) for positioning the coating device (2) relative to the substrate (1) in the radial direction of the substrate (1).

7. the coating positioning device has a distance adjustment device; the distance adjusting device has a distance measuring device for measuring the distance between the coating device (2) and the substrate (1); 10. The layer production system according to any one of the preceding claims, wherein the distance adjusting device further comprises a distance setting device for setting the distance of the coating device (2) to the substrate (1) so that said distance corresponds to a predetermined value.

8. 10. A layer production system according to any one of the preceding claims, wherein a curing positioning device is provided for positioning the UV lighting device (21) relative to the curing device (20).

9. The curing positioning device of the curing device (20) has a distance adjustment device, the distance adjusting device has a distance measuring device for measuring the distance between the UV illumination device (21 a) and the surface of the polymer layer and / or the surface of the substrate (1); 10. The layer manufacturing system according to any one of the preceding claims, wherein the distance adjusting device further comprises a distance setting device for setting the distance of the UV illumination device (21 a) to the surface of the polymer layer and / or to the surface of the substrate (1) so that said distance corresponds to a predetermined value.

10. A method for producing a polymer layer on a cylindrical substrate (1), said method comprising the steps of: A step of coating a cylindrical substrate (1) with a flowable polymer to form a flowable polymer layer; curing the flowable polymer layer on the substrate (1); Fixing the cylindrical substrate (1) in a substrate receptacle; During coating, translating the coating device (2) relative to the substrate (1) in the longitudinal direction (X) of the substrate (1); During curing, translating a curing device (20) relative to the substrate (1) in the longitudinal direction (X) of the substrate (1); rotating the substrate (1) held in the substrate receptacle in a rotational direction (R) during coating and curing; controlling the two translational movements and the rotational movement of the substrate.

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