Device and method for applying and curing a polymer layer on a cylindrical body

Abstract

The invention relates to a layer producing system for producing a polymer layer on a cylindrical substrate (1), comprising a coating device (2) for coating the cylindrical substrate (1) with a flowable polymer and producing a still flowable polymer layer; a curing device (20) for curing the still flowable polymer layer on the substrate (1); a substrate receiving area for supporting the cylindrical substrate; a coating translation device for producing a translational movement of the coating device (2) relative to the substrate (1) in a longitudinal direction (X) of the substrate; a curing translation device for producing a translational movement of the curing device (20) relative to the substrate in the longitudinal direction (X) of the substrate; a rotational device for moving the substrate (1) supported in the substrate receiving area in a rotational direction (R); and a movement controller which is designed to coordinate the movements carried out by the two translation devices with the movement of the rotational device.

Description

[0001] Device and method for applying and curing a polymer layer on a cylindrical body

[0002] The invention relates to a device and a method for producing a polymer layer on a cylindrical substrate. In particular, the invention relates to a device and a method for applying and curing such a polymer layer on the substrate.

[0003] Such a substrate can be, for example, a printing form that can be coated with a polymeric coating material. The term "substrate" or "printing form" is used below as a generic term for gravure printing forms, relief printing forms, or structural forms for embossing, but also for coating rollers or inking rollers.

[0004] WO 2021 / 052641 A1 discloses a printing form and a polymeric coating material therefor. The coating material is a polymeric nanocomposite that can be built up as a single layer for printing forms. The polymeric nanocomposite is applied in flowable form to the cylindrical outer surface of the printing form and subsequently cured by irradiation with UV light. The resulting polymer layer can be structured, for example, using infrared lasers to create a surface structure that has, for example, cells or structures for ink absorption or embossing, as also described in WO 2021 / 052641 A1.

[0005] Applying and curing a still-flowing polymer, such as the nanocomposite mentioned above, is complex. Curing is primarily achieved with UV light. To achieve efficient and low-emission (i.e., ozone-free) curing, UV LEDs are increasingly being used. These LEDs rely on surface inerting due to the predominant oxygen inhibition of the surface during radical polymerization.

[0006] The surface quality requirements of the polymer coating are high, as this can directly impact print quality when the cylindrical substrate is a printing cylinder, such as a gravure cylinder. An uneven polymer surface would result in a poor print image.

[0007] Coating a substrate with a polymer therefore requires, on the one hand, a high degree of precision to produce the polymer layer with the appropriate quality. This is especially true when the polymer layer is applied to a printing form, such as a gravure cylinder, because the quality of the polymer layer also influences the quality of the subsequent print. On the other hand, the coating must be efficient and cost-effective to be used, for example, in a printing company.

[0008] This also applies to the curing of the polymer after the coating process. Curing must be efficient and rapid.

[0009] Therefore, the object of the invention is to provide a layer production system for producing a polymer layer on a cylindrical substrate, with which flowable polymer can be applied to the substrate and subsequently cured.

[0010] This object is achieved according to the invention by a layer production system having the features of claim 1. A method for producing a cured polymer layer is specified in the independent claim. Advantageous embodiments are specified in the dependent claims.

[0011] A layer production system for producing a polymer layer on a cylindrical substrate is specified, comprising a coating device for coating the cylindrical substrate with a flowable polymer and producing the still-flowable polymer layer; a curing device for curing a still-flowable polymer layer on the substrate; a substrate holder for supporting the cylindrical substrate; a coating translation device for generating a translational movement of the coating device relative to the substrate in a longitudinal direction of the substrate; a curing translation device for generating a translational movement of the curing device relative to the substrate in a longitudinal direction of the substrate; a rotation device for moving the substrate supported in the substrate holder in a rotational direction.and with a motion controller configured to coordinate the movements by the two translation devices with the movement of the rotation device;

[0012] In particular, coordination allows for a spiral relative movement of the coating device or curing device relative to the substrate surface. The layer generation system makes it possible to first coat the outer surface of the substrate with a polymer layer. To do this, the coating device moves relative to the substrate surface along a spiral path.

[0013] After the polymer is applied, curing occurs using the curing device, which also moves along a spiral path relative to the substrate surface. Re-clamping the substrate is not necessary. Instead, the substrate can remain in the substrate holder, which rotates it during the coating process and subsequently during the curing process.

[0014] The coating device and the curing device, for their part, are moved only in the longitudinal and translational directions, respectively. In addition, the respective functional heads (nozzle for dispensing the flowable polymer in the coating device; UV light device in the curing device) can also be moved with respect to their distance from the substrate or polymer surface, i.e., in the radial direction relative to the substrate, as will be explained later.

[0015] The coating device can therefore be moved relative to the rotating substrate. The direction of translation can in particular be the longitudinal direction of the substrate, for example its central axis, while the substrate itself is rotated about its main axis or central axis. The desired relative spiral movement can be achieved through the superimposed movement of the rotation of the substrate and the translation of the coating device. This allows the flowable material to be applied evenly to the surface of the substrate, taking a spiral path. The path elements should be placed next to one another without gaps so that the remaining small gap can be easily closed by the action of a doctor blade, e.g. a smoothing doctor blade (described later). Ideally, the spiral movement can be adjusted so precisely that practically no gaps arise between the adjacent layers.

[0016] Accordingly, the curing device for curing the polymer can also be moved relative to the rotating substrate. The translation direction can be, in particular, the longitudinal direction of the substrate, e.g., its central axis, while the substrate itself is rotated about its main axis or central axis. The desired relative spiral movement can be achieved through the superimposed movement of the rotation of the substrate and the translation of the curing device. This allows the polymer to be cured evenly on the surface of the substrate. In particular, the polymer can be cured seamlessly and effectively due to the resulting spiral path of the UV radiation.

[0017] The coating device may comprise: a feed nozzle for applying the material to a substrate; a smoothing blade arranged downstream of the feed nozzle and configured to smooth a surface of the material applied to 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 can be variable; and wherein the force generating device can comprise a force control for adjusting the force that can be applied to the smoothing blade by the force generating device.

[0018] The cylindrical substrate to be coated can be rollers of all kinds, in particular printing forms such as gravure forms or cylinders, structural forms or cylinders, embossing forms or cylinders and relief printing forms or cylinders or coating rollers and inking rollers, e.g. for flexographic printing.

[0019] The flowable material can in particular be a flowable polymer material.

[0020] For example, it can be a polymeric coating material, as described, for example, in WO 2021 / 052641 A1. In particular, the polymer can be a coating material for coating a printing form, comprising a liquid starting material that is polymerizable by UV light to form a polymer matrix, a filler that has a sub-microscale size, wherein the coating material contains, in addition to the sub-microscale filler, a further filler, wherein the sub-microscale filler is in particle form and whose size is in a range between 100 nm and 999 nm, wherein the further filler is a nanoscale filler, such that the further filler has filler particles with a nanoscale size in a range between 1 nm and 99 nm, wherein the sub-microscale filler consists of at least one metal oxide and / or a semimetal oxide selected from metal oxide-coated mica,TiCu or (Sn, Sb)O2, wherein the nanoscale filler comprises metal and / or semi-metal oxides selected from Al2O3, SiO2, TiO2, ZrO2, or organometallic particles, wherein the sub-microscale filler is covalently incorporated into a polymer matrix of the starting material, wherein the nanoscale filler is included to increase wear resistance and is covalently incorporated into the polymer matrix of the starting material, and wherein the sub-microscale filler in the starting material can cause an absorption of IR radiation that is higher than an absorption without filler.

[0021] The smoothing blade is arranged downstream of the feed nozzle and is suitable for smoothing the layer of material applied to the substrate and, in particular, for closing gaps and gaps that have arisen between adjacent layers of material when the material was applied.

[0022] To do this, the smoothing blade is pressed onto the material layer using the force-generating device, with the contact pressure ideally being regulated. Excessive contact force leads to a significant change in the layer thickness distribution, while insufficient contact force prevents the transition gap between the adjacent layers from closing. It has been shown that, due to different viscosities, surface tensions, and other material variables, different surface pressures should be achievable with the smoothing blade.

[0023] The smoothing blade can consist of a thin plastic sheet that can be deformed in a suitable manner so that it adapts to the surface of the material to be smoothed.

[0024] The force-generating device is designed to deflect and move the smoothing blade from its rest position. The rest position is, in this respect, a starting position. Using the force-generating device and the associated force control, the force applied to the smoothing blade by the force-generating device can be precisely adjusted so that the smoothing blade, in turn, is pressed onto the material to be smoothed with the appropriate force.

[0025] The material layer thickness can be, for example, 10 to 500 µm, especially 10 to 250 µm as the target layer thickness. Deviations from the target layer thickness should be minimal, e.g., within a range of up to ±5% or up to ±3%.

[0026] The curing device may comprise: a UV light device for generating UV light and providing the UV light at a light opening; a curing gap arranged in front of the light opening; an inert gas supply device for supplying inert gas to the curing gap upstream of 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.

[0027] The polymer material was applied to the outer surface of the substrate in a suitable manner before the curing process and is still flowable in this state, i.e. before curing.

[0028] The UV light device generates UV light, which exits the light aperture and from there can be applied directly to the polymer layer to be cured on the substrate. For this purpose, the curing gap is positioned in front of the light aperture and forms a narrow inerting and irradiation channel. The formation of the curing gap or channel can be ensured by precisely positioning the curing device relative to the polymer surface (and thus the substrate surface), as will be explained later.

[0029] The curing gap is at least partially open to the polymer layer to be cured. In particular, the curing gap is at least partially open on its side facing the substrate. The curing gap can have a gas inlet for admitting the inert gas and a gas outlet for discharging the inert gas. In the curing gap itself, the light opening is arranged opposite the polymer layer to enable curing of the polymer layer by irradiation with UV light.

[0030] The oxygen measuring device is used to measure the oxygen content in the inert gas discharged from the light opening. In particular, the residual oxygen content in the inert gas is measured. To achieve the desired protective effect of the inert gas on the polymer layer, the inert gas must have a specific concentration, which can be determined indirectly by measuring the residual oxygen content in the inert gas stream. For this purpose, the oxygen measuring device can be equipped with a lambda probe (X-probe). Based on the results of the residual oxygen measurement, the required amount of inert gas can be adjusted and supplied at the upstream end via the inert gas supply device. This ensures a constant supply of inert gas in the curing gap during UV irradiation. At the same time, excessive inert gas consumption can be prevented, allowing the curing process to be carried out economically and in a resource-efficient manner.Nitrogen is particularly suitable as an inert gas, as it provides sufficient inerting effect.

[0031] The curing device allows curing of a polymer layer on a cylindrical substrate, regardless of the shape or format of the substrate.

[0032] As explained above, the coating device and optionally the curing device can move longitudinally along the lateral surface of the substrate parallel to the main axis of the cylindrical substrate.

[0033] The coating device and / or the curing device can each perform a spiral movement relative to the substrate. This results from the fact that the substrate can be rotated in the direction of rotation, while the coating device and the curing device perform a translational movement along the long side of the substrate. The resulting relative movement then corresponds to a spiral movement. The spiral movement enables both the coating device, when applying the flowable polymer, and the curing device, when curing the polymer layer created on the substrate, to cover the desired cylindrical surface of the substrate.

[0034] A coating positioning device may be provided for the coating device for positioning the coating device relative to the substrate in the radial direction of the substrate.

[0035] The coating positioning device may comprise a distance control device, wherein the distance control device may comprise a distance measuring device for measuring the distance between the coating device and the substrate, and wherein the distance control device may comprise a distance setting device for adjusting the distance of the coating device to the substrate such that the distance corresponds to a predetermined value.

[0036] The distance measurement can be performed inductively, capacitively, or laser-assisted, allowing the distance to be adjusted variably and with mechanical precision. The distance measuring device thus represents a distance sensor.

[0037] Furthermore, a curing positioning device can be provided for the curing device for positioning the UV light device. The curing positioning device can—like the coating positioning device—have a distance control device. The distance control device can have a distance measuring device for measuring the distance between the curing device and the substrate, and the distance control device can have a distance setting device for adjusting the distance of the curing device from the substrate such that the distance corresponds to a predetermined value.

[0038] The distance measurement for the curing device can also be performed inductively, capacitively, or laser-assisted, allowing the distance to be adjusted variably and with mechanical precision. Here, too, the distance measuring device represents a distance sensor.

[0039] A method for producing a polymer layer on a cylindrical substrate is provided, comprising the steps:

[0040] Coating the cylindrical substrate with a flowable polymer and creating a flowable polymer layer;

[0041] Curing the flowable polymer layer on the substrate;

[0042] Carrying the cylindrical substrate in a substrate holder;

[0043] Moving the coating device in a translational movement relative to the substrate in a longitudinal direction of the substrate during coating;

[0044] Moving the curing device in a translational motion relative to the substrate in a longitudinal direction of the substrate during curing;

[0045] Moving the substrate supported in the substrate holder in a rotational direction during coating and during curing; and coordinating the two translational movements with the rotational movement of the substrate.

[0046] During coating of the cylindrical substrate and during curing of the polymer layer, the substrate should be supported in a suitable manner in the substrate holder so that the substrate surface is easily accessible.

[0047] These and other features and advantages of the invention are explained in more detail below using examples with the aid of the accompanying figures. They show:

[0048] Fig. 1 shows a coating system for applying a polymer layer to a cylindrical substrate; Fig. 2 shows a coating device as part of the coating system of Fig. 1, for coating a cylindrical substrate with a polymer;

[0049] Fig. 3 is a sectional side view of the device of Fig. 2;

[0050] Fig. 4 is an enlarged detail “C” from Fig. 2;

[0051] Fig. 5 shows a curing system for curing a polymer layer on a cylindrical substrate;

[0052] Fig. 6 shows a curing device as part of the curing system of Fig. 5;

[0053] Fig. 7 is an enlarged detail of the hardening device of Fig. 6; and

[0054] Fig. 8 is a sectional side view of the hardening device of Fig- 6 -

[0055] Fig. 1 shows a perspective view of a coating system as part of a layer production system for producing a polymer layer on a cylindrical substrate 1.

[0056] In the example shown, the substrate 1 is a printing form, namely a gravure cylinder for use in gravure printing. The gravure cylinder is to be coated with a flowable polymer. This can be, for example, the nanocomposite known from WO 2021 / 052641 A1. The polymer coating of the gravure cylinder is suitable for laser treatment, in particular with a near-field infrared (NIR) laser, to create small depressions, so-called cells, which can absorb the printing ink and transfer it to the object to be printed. For this purpose, the polymer layer must have a relatively small thickness (layer thickness), e.g. 10 μm to 500 μm, in particular 10 μm to 250 μm.

[0057] The substrate 1 or the gravure cylinder is rotatably mounted in a holder (not shown) in a rotational direction R. A coating device 2 is provided on the outside of the substrate 1, which can be moved in a translational direction X along the outside of the substrate 1. The coating device 2 serves to apply the still-flowable polymer material to the cylindrical outer surface of the substrate 1.

[0058] When the translational movement of the coating device 2 in the translation direction X and the rotation of the substrate 1 in the rotation direction R are superimposed, the coating device 2 performs a spiral movement relative to the outside of the substrate 1, as shown in Fig. 1 by an arrow S. As a result, flowable polymer material with a width of, for example, a few millimeters, for example 5 mm to 30 mm, can be applied to the outside of the substrate 1 using the coating device 2. Due to the spiral relative movement, one polymer layer can be applied next to the other in a spiral or helical manner, so that ultimately the entire outer surface of the substrate or part of it is uniformly covered with a polymer layer.With the help of smoothing elements, which will be explained later, a gap that arises between the adjacent polymer layers can be closed uniformly, so that a uniform, homogeneous polymer layer is created.

[0059] To apply the polymer material, the coating device 2 must maintain a uniform, very close distance from 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 comprise a distance control device with a distance measuring device 3. Depending on the embodiment, the distance measuring device 3 can operate as an inductive, capacitive, or laser-based distance sensor and support the distance control.

[0060] Figs. 2 to 4 show the coating device 2 in detail, wherein Fig. 2 represents a main section, Fig. 3 a sectional side view of Fig. 2 and Fig. 4 an enlarged detail C of Fig. 2.

[0061] The coating device 2 has a carrier body 5. A feed nozzle 6 is held in the carrier body 5, to which coating material 7 in the form of flowable polymer material is fed. The coating material 7 can be fed by a continuous, pulsation-free, and precise material feed, e.g., with the aid of syringe pumps or eccentric screw pumps (dispensers). The feed nozzle 6 has a cylindrical material feed 8 that tapers conically toward an outlet opening 9. The outlet opening 9 can have a depth T of, e.g., 1 to 3 mm and a width B of 5 to 30 mm, although other dimensions are also possible.

[0062] In addition, the feed nozzle 6 can taper toward the outlet opening 9 (material outlet) at a taper angle. A taper angle a of, for example, 1° to 7° ensures laminar flow and an increasing fluid velocity of the coating material 7 shortly before the material exits.

[0063] It has been found that at distances between the feed nozzle 6, or in particular the outlet opening 9 of the feed nozzle 6, and the substrate 1 in the range of 1xS to 4xS, where S is the desired layer thickness on the substrate 1, a sufficiently large meniscus or heel is created at the nozzle outlet, ensuring complete wetting across the entire nozzle width. A constant distance thus also results in a constant layer thickness.

[0064] Downstream of the feed nozzle 6, viewed in the direction of rotation, a smoothing blade 10 is attached to the carrier body 5 to smooth the surface of the polymer material applied to the substrate 1. The smoothing blade 10 can be, for example, a plastic sheet. The plastic surface of the smoothing blade 10 is well suited to achieving the desired surface quality on the smoothed polymer.

[0065] A support squeegee 11 is arranged on the back of the smoothing squeegee 10, extending over the entire back surface of the smoothing squeegee 10. The support squeegee 11 can be made of spring steel. The support squeegee 11 thus supports the shape of the smoothing squeegee 10 and ensures a sufficiently large pressing force of the smoothing squeegee 10 on the polymer to be smoothed or spread.

[0066] Fig. 4 shows the smoothing squeegee 10 and the supporting squeegee 11 in an enlarged view.

[0067] On the front side of the smoothing squeegee 10, a return squeegee 12, also made of steel or spring steel, is provided, which extends over a partial surface of the smoothing squeegee 10 (Fig. 4). For example, the return squeegee 12 can extend over half or one-third of the surface of the smoothing squeegee 10. The squeegees 10, 11, 12 are jointly attached laterally to a squeegee attachment 13 on the carrier body 5.

[0068] Located at the rear of the smoothing squeegee 10 is a pressure piston 14, which is actuated and moved by a pneumatic cylinder 15, which in turn is controlled by compressed air via a pneumatic supply 16. The compressed air in the pneumatic cylinder 15 can press the pressure piston 14 downward against the support squeegee 11 and thus the smoothing squeegee 10, thus pressing the support squeegee 11 with the smoothing squeegee 10 against the return squeegee 12. The return squeegee 12 exerts a counterforce against the action of the pressure piston 14, so that a force equilibrium is established depending on the applied air pressure. This allows the contact force of the smoothing squeegee 10 against the polymer material to be smoothed to be precisely adjusted.

[0069] The contact pressure of the smoothing blade 10 on the applied polymer layer can be adjusted using a control system. Excessive contact pressure leads to a significant change in the layer thickness distribution, while insufficient contact pressure prevents the transition gap between the individual spiral coatings from closing. It has been shown that, due to different viscosities, surface tensions, and other material variables, a range of surface pressures of the smoothing blade 10 on the polymer material must be feasible.

[0070] The width of the smoothing blade 10 can be two to three times, up to five times, or up to ten times the width of a spiral layer in order to ensure a large contact surface and uniform layer homogenization.

[0071] Fig. 5 shows a curing system as a further part of the layer production system for producing a polymer layer on a cylindrical substrate. The components shown in Fig. 5 can, in particular, represent a supplement to the components shown in Fig. 1, so that the entire layer production system combines the components of Figs. 1 and 5, i.e., first applying a layer of a flowable polymer to the substrate 1 and then curing the polymer layer on the substrate 1.

[0072] Accordingly, the curing system of Fig. 5 assumes that the substrate 1 is already covered with a flowable polymer layer, which now needs to be cured to become dimensionally stable and serve its intended purpose, e.g., as a gravure printing roller. The substrate 1, e.g., the gravure printing roller, continues to be held in the holder (not shown) and rotated in the direction of rotation R, as in the system of Fig. 1.

[0073] A curing device 20 is arranged on the circumference of the substrate 1, which cures the polymer layer using UV light.

[0074] The entire layer generation system formed with components from Figs. 1 and 5 can thus comprise the coating device 2 shown in Fig. 1 and the curing device 20. This allows a polymer layer to be first applied to the outer surface of the substrate 1 by the coating device 2 and subsequently cured by the curing device 20 using UV light irradiation. In both process steps, the substrate 1 can be rotated about its main or longitudinal axis, while the coating device 2 and the curing device 2 are moved along the outer surface.

[0075] When UV curing polymers using LEDs, there is a risk that the free radicals of the photoinitiator released by the UVA radiation from the LED will be bound by atmospheric oxygen, thus preventing complete surface curing. Therefore, UV irradiation must be carried out in an inert gas atmosphere. To achieve this, the curing device 20 comprises not only a UV light device 21 but also an inert gas supply device 22.

[0076] Analogous to the coating device 2 in Fig. 1, the curing device 20 also has a curing translation device (not shown) with which the curing device 20 can be moved in a translation direction X along the longitudinal axis of the substrate 1. Parallel to this, the substrate rotates in the rotation direction R, resulting in the spiral movement S. In this way, the curing device 20 can cover the entire surface of the polymer layer applied to the outer surface of the substrate 1 with the UV light device 21 and thus cure the polymer.

[0077] Similar to the coating device 2 described above, the curing device 20 also has a curing positioning device (not shown) with a distance control device for adjusting the distance of the curing device 20 in the Z direction, i.e., in the direction of the surface of the substrate 1 (radial direction of the substrate 1). A distance measuring device 23 is provided for this purpose. Precise maintenance of the distance is important for achieving a satisfactory curing result.

[0078] Fig. 6 shows the curing device 20 in an enlarged sectional view. The curing device 20 is shown in relation to two substrates 1a, 1b of different sizes to illustrate that the curing device 20 can be used for substrates 1 with significantly different diameters.

[0079] Approximately in the middle, the curing device 20 has the UV light device 21, which is arranged vertically in the example shown and at the bottom of which the UV light can emerge via a light opening 21a (Fig. 7), as will be explained later.

[0080] The inert gas supply device 22, located to the right of the UV light device 21 in Fig. 6, has a gas supply line 24 through which inert gas is supplied from a storage device, e.g., a gas cylinder or a gas tank. Nitrogen is particularly suitable as an inert gas. The flow of the inert gas to the light opening 21a of the UV light device 21 is controlled by a mass flow controller 25. This will be explained in more detail later.

[0081] Fig. 7 shows the area below the UV light device 21 in an enlarged view compared to Fig. 6. The light opening 21a, which serves as the exit opening of the UV light device 21 and through which the UV light exits to irradiate the polymer material, is covered by a UV-transparent quartz glass cover 26.

[0082] A curing gap 27 is formed between the UV light device 21 or the quartz glass cover 26 on the one hand and the surface of the substrate 1 covered with the polymer layer, spaced therefrom, on the other hand. Upstream of the quartz glass cover 26 and the curing gap 27, the inert gas supply device 22 has a dispensing nozzle 28, through which the inert gas can be introduced into the curing gap 27 via a gas inlet 29. The dispensing nozzle 28 is arranged at the end of a dispensing funnel 30, which is followed by a dispensing channel 31, as shown in Fig. 8.

[0083] Fig. 8 shows a section through the induction channel 31 of Fig. 7. It can be clearly seen that the inert gas supplied via a gas line 32 from the mass flow controller 25 is fanned out in the induction funnel 30 and subsequently calmed in the narrow induction channel 31. In the induction channel 31, which also serves as a calming section, a substantially laminar flow of the inert gas can be achieved, so that the inert gas is discharged over the entire width of the induction nozzle 28 and can cover polymer material on the substrates 1a, 1b before this area of ​​the polymer material, which is then protected by inert gas, reaches the light opening 21a on the quartz glass cover 26 in the curing gap 27, where the UV irradiation takes place.

[0084] After leaving the injection nozzle 28, it is to be expected that the inert gas will partially mix with atmospheric oxygen, since the area of ​​the gas inlet 29 into the curing gap 27 cannot be completely sealed from the environment. Thus, the curing gap 27 is not flowed through by pure inert gas, but rather by a gas mixture that, in addition to inert gas, will also contain residual oxygen components. The sealing measures provided to reduce the ingress of ambient air, as well as the measures to achieve a specified proportion of inert gas in the gas mixture, will be explained later.

[0085] Downstream of the quartz glass cover 26 or the curing gap 27, i.e., after UV irradiation, the curing gap 27 ends at a gas outlet 33. A gas discharge device 34 with a downstream measuring chamber 35 is provided there. The gas discharge device 34 can, in particular, be designed as a gap and create a connecting channel from the end of the curing gap 27 (gas outlet 33) to the measuring chamber 35. A portion of the inert gas is thus discharged via the gas discharge device 34 or to the measuring chamber 35, while another portion of the inert gas, not captured by the gas discharge device 34, can escape to the environment.

[0086] To reduce inert gas leaks or losses into the environment, the curing gap 27 is sealed on all sides, i.e., on all four sides, by non-contact seals, which are designed, in particular, as doctor blade seals 36. The doctor blade seals 36 comprise one or more sheet metal elements arranged in staggered rows and representing flow obstructions, so that the inert gas cannot flow out unhindered. This, and in conjunction with a gas conveying device (described later), ensures that only a relatively small portion of the inert gas escapes into the environment, while the remaining portion is extracted via the measuring chamber.

[0087] A lambda probe (X-probe) 37 is provided in the measuring chamber 35 as part of an oxygen measuring device. With the help of the oxygen measuring device, the (residual) oxygen content in the inert gas downstream of the location of the UV irradiation at the light opening 21a can be measured. This allows the inflow of inert gas or the ratio of inert gas to oxygen to be regulated using the mass flow controller 25 in order to, on the one hand, keep the residual oxygen content within a predetermined range and, on the other hand, also keep the inert gas content within a predetermined range in order to ensure effective protection of the polymer surface from oxidation during UV irradiation. A residual oxygen content of 0.1% to 10%, in particular of 0.5% to 5%, depending on the curing behavior of the polymer mixture, has proven suitable. The inert gas flow is effected by means of a gas conveying device 38, which has an exhaust fan 39.The exhaust fan 39 creates a negative pressure with which the gas mixture is extracted from the inert gas supply device 22 via the curing gap 27. The gas flow thus occurs via the gas supply line 24, the mass flow regulator 25, the gas line 32, the induction funnel 30, the induction nozzle 28, the curing gap 27, the gas discharge device 34, the measuring chamber 35, and the exhaust fan 39.

Claims

Patent claims Layer production system for producing a polymer layer on a cylindrical substrate (1), with a coating device (2) for coating the cylindrical substrate (1) with a flowable polymer and producing a still flowable polymer layer; a curing device (20) for curing the still flowable polymer layer on the substrate (1); a substrate holder for carrying the cylindrical substrate; a coating translation device for generating a translational movement of the coating device (2) relative to the substrate (1) in a 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 for moving the substrate (1) carried in the substrate holder in a rotational direction (R);and with a motion controller configured to coordinate the movements by the two translation devices with the movement of the rotation device. The layer production system according to claim 1, wherein the coating device (2) comprises: a feed nozzle (6) for applying the material to the substrate (1); a smoothing blade (10) arranged downstream of the feed nozzle (6) and configured to smooth a surface of the material applied to the substrate (1); and a force generating device (14, 15) for applying a force to the smoothing blade (10); wherein the force that can be applied to the smoothing blade (10) by the force generating device (14, 15) is variable.and wherein the force generating device (14, 15) has a force control for adjusting the force that can be applied to the smoothing blade (10) by the force generating device. The layer production system according to claim 1 or 2, wherein the curing device (20) comprises: a UV light device (21) for generating UV light and providing the UV light at a light opening (21a); ​​a curing gap (27) arranged in front of the light opening; an inert gas supply device (22) for supplying inert gas to the curing gap (27) upstream of the light opening (21a); ​​an inert gas flow through the curing gap (27); and an oxygen measuring device (37) for measuring the oxygen content in the inert gas downstream of the light opening (21a).

4. Layer production system according to one of the preceding claims, wherein by coordinating the translational movement of the coating device (2) and / or the curing device (20) with the rotational movement of the substrate (1) a spiral movement (S) is effected as a relative movement.

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

6. Layer production system according to 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. A layer production system according to any one of the preceding claims, wherein the coating positioning device comprises a distance control device; the distance control device comprises a distance measuring device for measuring the distance between the coating device (2) and the substrate (1); and wherein the distance control device comprises a distance setting device for adjusting the distance of the coating device (2) from the substrate (1) such that the distance corresponds to a predetermined value.

8. Layer production system according to one of the preceding claims, wherein a curing positioning device is provided for the curing device (20) for positioning the UV light device (21).

9. Layer generation system according to one of the preceding claims, wherein The curing positioning device for the curing device (20) comprises a distance control device; the distance control device comprises a distance measuring device for measuring the distance between the UV light device (21a) and a surface of the polymer layer and / or a surface of the substrate (1); the distance control device comprises a distance setting device for adjusting the distance of the UV light device (21a) to the surface of the polymer layer and / or the surface of the substrate (1) such that the distance corresponds to a predetermined value. A method for producing a polymer layer on a cylindrical substrate (1), comprising the steps: Coating the cylindrical substrate (1) with a flowable polymer and producing a flowable polymer layer; Curing the flowable polymer layer on the substrate ( 1 ); Carrying the cylindrical substrate (1) in a substrate holder; Moving the coating device (2) in a translational movement relative to the substrate (1) in a longitudinal direction (X) of the substrate (1) during coating; Moving the curing device (20) in a translational movement relative to the substrate (1) in a longitudinal direction (X) of the substrate (1) during curing; Moving the substrate (1) carried in the substrate holder in a direction of rotation (R) during coating and during curing; and Coordinating the two translational movements with the rotational movement of the substrate.

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