Method for controlling coating glossy on coating line for rolling products

Abstract

FIELD: automated processes for continuous application.SUBSTANCE: automated processes for the continuous application of a coating to metal before the manufacture of the final product. Invention concerns a method for controlling the gloss of an organic coating formed on a moving strip on a coil coating line. The coating line comprises a paint application device, a heating device containing a heating module, an ultraviolet curing device and an electron beam curing device, arranged sequentially along the path P of the moving strip. The method includes correcting the deviation of the measured gloss G beyond the specified gloss range RS, wherein this correction step includes the sub-step of calculating the corrected temperature TC, which the wet film must reach at least in the width section upstream from the ultraviolet curing device, in accordance with the equation TC = T + K (G - GS) and the sub-step of adjusting the setting parameter of the coil coating line taking into account the calculated corrected temperature TC.EFFECT: invention provides a method for efficient and reproducible control of the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip on a coil coating line.14 cl, 4 dwg

Description

[0001] The present invention relates to a method for controlling the gloss of an organic coating applied to a moving strip in a coil coating line. Specifically, the moving strip is a steel strip with a metallic coating.

[0002] Coil coating is a continuous automated process for applying a coating to metal before manufacturing finished products. Steel or aluminum substrates arrive in coils from rolling mills. The metal coil is positioned at the beginning of the coil coating line. In a single, continuous process, the coil is unwound, pre-cleaned, treated, primed, and painted, then wound at the other end and packaged for shipping.

[0003] The product obtained through this process is pre-painted metal, also known as coiled metal, pre-finished metal, or pre-coated metal. It is widely used in construction and electrical equipment.

[0004] Solvent-based paints have traditionally been used to coat coiled products. However, there has been recent interest in radiation curing, which involves curing materials using ultraviolet radiation (UV processes) or electron beams (EB processes). These paints, known as radiation-curable paints (radcure), are solvent-free, and the curing process is initiated either by exposure to high-energy UV radiation, possibly in combination with suitable photoinitiators, or by exposure to accelerated electrons. Photoinitiators absorb UV radiation and generate free radicals. These free radicals react with the double bonds of the monomers, causing a chain reaction and polymerization. Curing using ultraviolet C (UV-C) and electron beam curing (EB) does not require initiators.High radiation energy ensures the formation of a sufficient number of reactive particles (radicals) for the spontaneous polymerization process.

[0005] One of the characteristics of radiation-curable paints is the formation of high-gloss organic coatings due to the high surface tension of the coating. To reduce this gloss and meet the requirements of the pre-painted market (gloss is typically 15-30 gloss units (GU) for the building materials market), paint suppliers add matting agents, as with solvent-based paints. However, radiation-curable paints are quite viscous due to the lack of solvent, so only a small amount of matting agent can be added, which prevents low gloss levels from being achieved. Furthermore, the migration of matting agents to the coating surface to achieve the desired gloss level is also very limited due to the high curing speed of radiation-curable paints compared to solvent-based paints (1-2 seconds versus 12-25 seconds).

[0006] One method for mitigating this problem is described in WO81 / 00683, which discloses a curing process in which the coating is first irradiated with curing radiation at wavelengths to which it responds but which have virtually no distribution below approximately 300 nm (e.g., UV radiation), and then irradiated with curing radiation at wavelengths to which the coating responds, including significant radiation at wavelengths below 300 nm (e.g., an electron beam). This curing method is known as dual curing. Gloss control is achieved through real-time adjustment of parameters including the spectral distribution, intensity or dose of the initial radiation, or the time interval between the initial and subsequent irradiation steps.

[0007] However, these real-time parameters were found to be insufficient for effective and reproducible gloss control.

[0008] Therefore, the object of the present invention is to eliminate the disadvantages of the prior art process by providing a method for efficiently and reproducibly controlling the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip on a coil coating line.

[0009] To achieve this object, the first object of the present invention is a method for controlling the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip on a coil coating line comprising a paint application device, a heating device comprising a heating module, an ultraviolet curing device and an electron beam curing device arranged sequentially along the path P of the moving strip, wherein the method includes the following steps:

[0010] - Setting the specified Gs value of organic coating gloss, specified R range S gloss of the organic coating and the proportionality coefficient K in a predetermined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing,

[0011] - Collecting the measurement data of the temperature T of the wet film at least in a section of the width of the moving strip upstream of the ultraviolet curing device and collecting the measurement data of the gloss G of the organic coating at least in a section of the width downstream of the electron beam curing device,

[0012] - Correction of the deviation of the measured gloss G beyond the specified range R S shine, while this stage of correction includes a sub-stage of calculating the corrected temperature T C, which the wet film must reach at least in the width section upstream of the UV curing device, according to equation 1:

[0013] T C = T + K (G - G S ) (1)

[0014] and the sub-step of adjusting the setting parameter of the coil coating line taking into account the calculated corrected temperature T C .

[0015] The method according to the invention may also include additional features listed below, considered individually or in combination:

[0016] - the heating device does not contain an infrared heater,

[0017] -The heating device is selected from induction heater, convector, forced air heater, water spray heater, air-water mist heater and heated roller.

[0018] - The method further includes a line initial setup step in which:

[0019] ○ collect data on process parameters and / or strip characteristics,

[0020] ○ set at least one initial condition for the line from the initial power PW0 of the heating module, the initial UV dose D0 of the ultraviolet curing device, and the initial distance L0 between the ultraviolet curing device and the electron beam curing device, taking into account the collected process parameters and / or strip characteristics,

[0021] - The sub-step of adjusting the setting parameter of the coil coating line includes adjusting the power of the heating module so that the wet film reaches the adjusted temperature T C at least in the section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device,

[0022] - the roll coating line additionally contains an inductor upstream of the paint application device,

[0023] - The sub-step of adjusting the setting parameter of the coil coating line includes adjusting the power of the inductor so that the wet film reaches the adjusted temperature T C at least in the section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device,

[0024] - UV curing device contains UV module,

[0025] - the installation stage additionally includes setting the maximum temperature T max for radiation-curing paint,

[0026] - the data collection stage additionally includes collecting data on the ultraviolet radiation dose D of the UV module,

[0027] - the sub-step of adjusting the setting parameter of the coil coating line includes:

[0028] ○ assess whether the value of T exceeds C value of T max ,

[0029] ○ If not, adjust the power of the heating module so that the wet film reaches the adjusted temperature T C at least in the section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device,

[0030] ○ if the value of T C exceeds the value T max :

[0031] ■ Calculate the corrected UV dose D to which the wet film should be exposed over at least the width portion in the UV module, according to equation 2:

[0032] D C = f1(D, G, G S ) (2)

[0033] ■ Adjust the setting parameter of the coil coating line other than the heating device power, taking into account the calculated adjusted dose D C UV radiation,

[0034] - the sub-step of adjusting the setting parameter of the coil coating line, which is not the power of the heating module, includes adjusting the power of the UV module so that the wet film at least in a section of the width of the moving strip is exposed to the adjusted dose D C UV radiation,

[0035] - The UV module is movable along the path P,

[0036] - the installation stage additionally includes setting the maximum dose D max UV radiation to which the wet film can be exposed in the UV module,

[0037] - the data collection step further includes collecting data on the distance L between the UV module and the electron beam curing device,

[0038] - the sub-step of adjusting the setting parameter of the coil coating line, which is not the power of the heating module, includes:

[0039] ■ assess whether the value of D exceeds C value D max ,

[0040] ■ If not, adjust the power of the UV module so that the wet film over at least a portion of the width of the moving strip is exposed to the adjusted dose D C UV radiation,

[0041] ■ if the value is D C exceeds the value of D max :

[0042] ● Calculate the adjusted distance L C between the UV module and the electron beam curing device according to equation 3:

[0043] L C = f2(L, G, G S ) (3)

[0044] ● Adjust the setting parameter of the coil coating line, which is not the power of the heating module and not the power of the UV module, taking into account the calculated adjusted distance L C ,

[0045] - the sub-step of adjusting the setting parameter of the coil coating line other than the power of the heating module and other than the power of the UV module includes adjusting the distance between the UV module and the electron beam curing device to the adjusted distance L C in such a way that at least in the section of the width of the moving strip downstream of the electron beam curing device, a gloss with a value of G is obtained on the organic coating S .

[0046] A second object of the invention is a coil coating line comprising a sequentially arranged: a paint application device, a heating device comprising a heating module, an ultraviolet curing device and an electron beam curing device, wherein the coil coating line also comprises a gloss control tool for controlling the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip on the coil coating line, wherein the gloss control tool comprises:

[0047] - setting module that sets the set value of G S gloss of organic coating, specified range R Sgloss of the organic coating and the proportionality coefficient K in a predetermined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing,

[0048] - a data receiving module that collects measurement data of the temperature T of the wet film at least in a section of the width of the moving strip upstream of the ultraviolet curing device and collects measurement data of the gloss G of the organic coating at least in a section of the width downstream of the electron beam curing device,

[0049] - correction module that corrects the deviation of the measured gloss G beyond the specified range R S gloss, while the correction includes the calculation of the corrected temperature T C, which the wet film must reach at least in the width section upstream of the UV curing device, according to equation 1:

[0050] T C = T + K (G - G S ) (1)

[0051] and adjust the setting parameter of the coil coating line taking into account the calculated corrected temperature T C .

[0052] The coil coating line according to the invention may also include the additional features listed below, considered individually or in combination:

[0053] - the heating device does not contain an infrared heater,

[0054] - The heating device is selected from an induction heater, a convector, a forced-air heater, a water spray heater, an air-water mist heater and a heated roller.

[0055] Other characteristics and advantages of the invention will be described in more detail in the following description.

[0056] The invention will be better understood by reading the following description, which is provided for purposes of explanation only and is in no way limiting, with reference to:

[0057] Fig. 1, which is a schematic representation of a coil coating line,

[0058] Fig. 2 is a block diagram of the first embodiment of the method, in accordance with the invention,

[0059] Fig. 3 is a block diagram of a second embodiment of the method, in accordance with the invention,

[0060] Fig. 4 is a block diagram of a third embodiment of the method, in accordance with the invention.

[0061] It should be noted that the terms relating to spatial orientation such as "upstream", "downstream", "downstream", "upper", "above", "below", "before", "after" ..., used in this description, refer to the positions and orientations of the various constituent elements of the coil coating line.

[0062] The method according to the invention is intended for strips, such as metal strips. Examples of metal strips are strips of steel, both carbon and stainless, aluminum, copper. In particular, the steel strips can be made without a coating or can be coated with a metallic coating on one or both sides of the strip. Examples of possible steels with a metallic coating are galvanized steel, steels coated with a zinc alloy containing 5 wt. % aluminum (Galfan®), steels coated with a zinc alloy containing 55 wt. % aluminum, approximately 1.5 wt. % silicon, the rest is zinc and unavoidable impurities due to the technology (Aluzinc®, Galvalume®), steels coated with an aluminum alloy containing 8-11 wt. % silicon and 2-4 wt.% iron, the rest is aluminum and inevitable impurities due to technology (Alusi®), steels coated with a layer of aluminum (Alupur®), steels coated with a zinc alloy containing 0.5-20% aluminum, 0.5-10% magnesium, the rest is zinc and inevitable impurities due to technology, steels coated with an alloy containing aluminum, magnesium, silicon, possible additional elements, the rest is zinc and inevitable impurities due to technology.

[0063] The method according to the invention is also intended for radiation-curable paints. The term "radiation-curable paints" refers to radiation-curable compositions that are "cured" or dried using short-wave ultraviolet (UV) radiation and / or high-energy electrons from electron beam (EB) sources. They typically include liquid monomers and oligomers into which pigments, fillers, additives, and photoinitiators can be dispersed, typically without the need for solvent or water. Thus, they are substantially solvent-free. Radiation-curable paints suitable for dual curing preferably include acrylate or methacrylate monomers and photoinitiators.

[0064] As shown in Fig. 1, the coil coating line 1, according to the invention, mainly comprises a paint application device 2, a heating device 3 containing a heating module, an ultraviolet curing device 4 and an electron beam curing device 5, arranged sequentially along the path P of the moving strip.

[0065] Path P is the path along which strip S moves from the entrance to the coil coating line to its exit. It is characterized by its width and length. Equipment for strip operations is located along this path.

[0066] Paint applicator 2 is a device that applies a wet film of paint to one or both sides of a strip at a predetermined paint thickness. Specifically, its purpose is to apply a wet film of radiation-curable paint. Within the context of the invention, the technology of the paint applicator is not limited.

[0067] According to an embodiment of the invention, the paint applicator 2 is a roller applicator. This is an automatic machine that coats one or both sides of a strip using rotating rollers. It is designed such that the strip passes through the machine, which applies a layer of paint to one or both sides of the strip. There are many designs of roller applicators, depending on the configuration of the coil coating line, the types of paints used, and the types of strips to be coated. A person skilled in the art will know which design is best suited for each case. Generally, a roller applicator includes a paint tray, a steel or ceramic pickup roller, and a rubber-coated coating roller. The purpose of the paint tray is to contain, transport, and, preferably, heat the paint.The pickup roller can be partially immersed in the ink and can rotate clockwise or counterclockwise to pick up the ink and transfer it to the coating roller. The coating roller then transfers the ink to the strip.

[0068] According to another embodiment of the invention, the paint application device 2 is a curtain coating machine. In this case, paint is applied to a horizontally positioned strip in the form of a curtain, which forms from above, typically perpendicular to the paint curtain. The paint flows under gravity from a die or cascade, while the strip is supported on a support roller. This method is capable of high line speeds and multi-layer coatings.

[0069] Examples of other paint applicator devices include knife applicators, dip or meniscus applicators, slot applicators, metering bar applicators, and sliding applicators.

[0070] Paint is typically applied by a paint applicator across the entire strip width. By default, the wet film width of the paint, and therefore the organic coating, is the same as the strip width.

[0071] The paint application device 2 is preferably equipped with at least one paint heating device suitable for heating and maintaining the paint at a predetermined temperature. Heating the paint facilitates its application. It also further facilitates gloss control, since it minimizes the energy requirements at the heating module level and, thus, minimizes the inertia of the heating module. In the case of a paint application device with a roller, the paint heating device may be a tray heater, i.e., a heater located in or around the paint tray. It may also be a temperature-controlled roller, in particular a temperature-controlled pickup roller, possibly in combination with a tray heater. In the case of a curtain coating machine, the paint heating device may be a heater located upstream of the die.It can also be a temperature controlled backing roller, possibly in combination with a heater.

[0072] Paint applicator 2 is preferably equipped with a temperature measuring device for measuring the temperature of the paint and / or wet film at the applicator. The temperature measuring device may be, for example, a temperature sensor, a pyrometer, or a thermal camera.

[0073] The coil coating line 1 further comprises a heating device 3 comprising a heating module arranged along the strip path P downstream of the paint applicator 2 and upstream of the ultraviolet curing device 4. Its purpose is to heat the wet film of radiation-curable paint. The heating device further improves the temperature control of the wet paint film before its surface is cured in the ultraviolet curing device. Since the temperature of the strip exiting the paint applicator decreases at a rate depending on a number of parameters (strip properties, strip width, strip thickness, line speed, etc.), the temperature of the wet film entering the ultraviolet curing device may vary significantly from time to time, which will adversely affect the gloss.Thanks to the heating device, the temperature of the wet film can be adjusted.

[0074] The heating device is preferably selected from an induction heater, a convector, a forced-air heater, a water spray heater, an air-water mist heater, and a heated roller. Preferably, the heating device does not include an infrared heater. In the case of water heaters, since a wet film of radiation-curable paint is applied to the top side of the strip, the water preferably only contacts the back side of the strip.

[0075] According to one embodiment, the heating device consists of a single heating module covering the entire width of the strip moving along the path P. In this case, the wet film is heated uniformly across its entire width as it passes through the heating device.

[0076] According to another embodiment, heating device 3 comprises multiple heating modules distributed across the width of path P. In other words, multiple heating modules form a row substantially parallel to the width of path P, i.e., perpendicular to the direction of strip movement. For clarity, the heating modules described herein are independent of each other and arranged adjacent to each other, but they may be physically inseparable. They may be individually controllable parts of a single heating device.

[0077] The heating modules are preferably selected from an induction heater, a convector, a forced-air heater, a water spray heater, an air-water mist heater, and a heated roller. Preferably, the heating modules do not include an infrared heater.

[0078] This design allows temperature variations across the stripe width to be corrected and minimized. Preferably, the wet film temperature variation across the stripe width at the heater outlet should be less than 1°C. This improves the uniformity of coating gloss across the stripe width.

[0079] According to another embodiment, heating device 3 comprises a base heater, spanning the entire width of path P, and multiple heating modules, as described above, arranged sequentially along the moving strip path. With this design, part of the energy required to achieve the desired wet film temperature at the outlet of the heating device is provided by the base heater. Each heating module independently provides the remaining energy and can regulate it as needed.

[0080] Heating device 3 is preferably located above path P to directly heat the wet film applied to the upper side of the strip. The heating device may also be located above and below path P to minimize temperature gradients.

[0081] Roll coating line 1 additionally includes an ultraviolet curing unit 4. This equipment is designed to cure the surface of the wet film of radiation-curable paint. It has been found that this surface curing creates a very fine texture on the film surface, which, in combination with matting agents and other additives, contributes to the gloss of the organic coating after the wet film is fully cured by the electron beam.

[0082] According to one embodiment, the ultraviolet curing device 4 covers the entire width of the moving strip path P. In this case, the wet film surface is uniformly cured across the entire width of the strip when exposed to UV radiation.

[0083] According to another embodiment, the ultraviolet curing device 4 comprises multiple UV modules distributed across the width of the path P. In other words, multiple UV modules form a row substantially parallel to the width of the path P, i.e., perpendicular to the direction of strip movement. For clarity, the UV modules described herein are independent of each other and arranged adjacent to each other, but they may be physically inseparable. They may be individually controllable parts of a single ultraviolet curing device.

[0084] This design allows different sections of the path / strip width to be exposed to different UV doses. This helps correct and minimize gloss variations across the strip width. Accordingly, the heating device preferably comprises multiple heating modules arranged in a row substantially parallel to the path width P. Each heating module is designed to heat a section of the strip width, which is then exposed to the UV radiation of a single UV module. In other words, each section of the width covered by a given UV module corresponds to the section of the width covered by the corresponding heating module.

[0085] UVA and UVB radiation are preferred. UVA is long-wave UV radiation in the range of 320-400 nm. UVB is short-wave UV radiation in the range of 280-320 nm. They can be obtained with conventional UV arc lamps.

[0086] UV curing device 4 is preferably movable along the path P of the moving strip. This allows the distance between the UV curing device and the electron beam curing device to be adjusted, i.e., increased or decreased. Indeed, it has been found that wrinkles or surface roughness initiated during UV curing further develop during the time interval between UV curing and electron beam curing, affecting the gloss of the organic coating.

[0087] In the case of multiple UV modules, each UV module can preferably move along the trajectory P independently of the others.

[0088] Roll coating line 1 additionally includes an electron beam curing unit 5. This equipment is designed to cure the wet film of radiation-curable paint, i.e., throughout its entire thickness. It also records the surface roughness that appears on the wet film surface during UV curing and that further develops during the time interval between UV curing and electron beam curing. The electron beam curing unit typically operates under the following conditions: 100-200 kV, 20-50 kGy, in an inert atmosphere with nitrogen and an O2 concentration below 200 ppm.

[0089] The coil coating line 1 further comprises a wet film temperature measuring device 6, located downstream of the heating device 3 and upstream of the ultraviolet curing device 4. This wet film temperature measuring device measures the temperature of the wet film before it enters the ultraviolet curing device. It can measure the wet film temperature across the entire width of the path P of the moving strip or can measure the temperature only over a section of the width. Examples of wet film temperature measuring devices include a pyrometer, a thermal chamber, and a thermocouple. The measured temperature can be expressed in °C, °F, or K.

[0090] In the case where the wet film temperature measuring device measures the temperature only in a width section, the measurement in this section can be considered as sufficiently applicable to the gloss control of the entire width of the strip.

[0091] Alternatively, multiple wet film temperature measuring devices are arranged downstream of the heating device 3 and upstream of the ultraviolet curing device to cover the entire width of the path P of the moving strip. They form a row substantially parallel to the width of the path P. Accordingly, the heating device preferably comprises multiple heating modules forming a row substantially parallel to the width of the path P, wherein each heating module is designed to heat a section of the strip width, the temperature of which is then measured by one wet film temperature measuring device.

[0092] In order to further improve the control of the wet film temperature in the ultraviolet curing device, the wet film temperature measuring device 6 and the ultraviolet curing device 4 are separated by no more than 2 meters, preferably no more than 1 meter, or the wet film temperature is measured no more than 4 seconds before the wet film is cured in the ultraviolet curing device, preferably no more than 2 seconds. Alternatively or additionally, the section of the path P of the moving strip between the wet film temperature measuring device and the ultraviolet curing device can be thermally insulated to maintain the wet film at the measured temperature before it is cured in the ultraviolet curing device.

[0093] The coil coating line 1 further comprises a gloss measuring device 7 located downstream of the electron beam curing device 5. This gloss measuring device measures the gloss of the organic coating after electron beam curing. It can measure the gloss of the organic coating over the entire width of the path P of the moving strip or can measure the gloss only over a section of the width. Examples of gloss measuring devices are glossometers. The measured gloss is preferably expressed in GU (gloss units). Gloss is preferably measured in accordance with ISO 2813:2014 and EN 13523-2:2021 standards. Preferably, the gloss is measured with a geometry of 20°, 60°, or 85°, i.e., the reflection angle is either 20°, 60°, or 85°. More preferably, the gloss is measured with a geometry of 60°.

[0094] In the case where the gloss measuring device measures the gloss only in a width section, the measurement in this section can be considered sufficiently applicable to the gloss control of the entire width of the strip.

[0095] Alternatively, multiple gloss measuring devices are arranged downstream of the electron beam curing device to cover the entire width of the path P. They form a row substantially parallel to the width of the path P. Accordingly, the heating device preferably comprises multiple heating modules forming a row substantially parallel to the width of the path P, wherein each heating module is designed to heat a portion of the strip width, the gloss of which is then measured by a single gloss measuring device. Accordingly, the ultraviolet curing device preferably comprises multiple UV modules forming a row substantially parallel to the width of the path P, wherein each UV module is designed to expose a portion of the strip width, the gloss of which is then measured by a single gloss measuring device, to UV radiation.

[0096] Roll coating line 1 is preferably equipped with a strip speed measuring device, preferably located at the guide roller level. An example of a strip speed measuring device is a tachometer mounted on the roller axis.

[0097] The coil coating line 1 may further comprise an inductor 8 located upstream of the paint applicator 2. It can heat the strip before it reaches the paint applicator. The presence of a warm strip in the paint applicator facilitates paint application. Furthermore, the temperature reached by the strip in the inductor can be adjusted to correct for possible gloss variations, as will be described in detail later.

[0098] The coil coating line 1 may further comprise an input section with an unwinding device 9 for unwinding the strip to be coated on the line. The unwinding device may be combined with a welding machine or a stitching machine such that the leading end of the strip to be coated can be attached to the trailing end of the preceding strip.

[0099] Alternatively, the coil coating line can be connected to the galvanizing line so that the strip coated with metal alloys contained in the galvanizing line's bath can be directly coated with an organic coating without the need to first coil it and then uncoil it.

[0100] The coil coating line 1 may additionally include an input accumulator 10, located in the input section of the line, downstream of the unwinding device, if used. The accumulator is a piece of equipment that "accumulates" a certain amount of strip. It consists of a set of upper and lower roller groups through which the metal strip is passed in a serpentine pattern, and accumulates a strip of metal of a certain length by moving two rows of rollers apart. The total length of the stored metal depends on the design speed of the coil coating line, which is typically 60 seconds under steady-state metal processing conditions. After the input section of the coil coating line stops, the roller groups move toward each other, and the metal accumulated in the accumulator continues to be fed to the rest of the coil coating line.

[0101] The coil coating line 1 may further comprise a cleaning section 11 positioned downstream of the input section, in particular downstream of the input accumulator, if used. In this section, the strip undergoes a surface preparation step. This preparation includes at least one step selected from the following: washing, degreasing, and conversion treatment. The purpose of washing is to remove loose dirt particles, possible residues of conversion solutions, and soap that may have previously formed, and to obtain a clean and chemically active surface. The purpose of degreasing is to clean the surface by removing all traces of organic contaminants, metal particles, and dust. Preferably, degreasing is carried out in an alkaline environment.Conversion treatment involves applying a conversion solution to the strip, which reacts chemically with the surface, thereby forming a conversion layer. This layer improves paint adhesion and corrosion resistance. Conversion treatment is preferably performed with a chromium-free acid solution. More preferably, the conversion treatment is based on hexafluorotitanic or hexafluorozirconic acid.

[0102] The coil coating line 1 may further comprise a primer section located upstream of the paint applicator 2 and downstream of the cleaning section, if used. In this section, a first coat of paint may be applied to the strip to form a primer coating. The primer section may comprise a primer applicator and curing equipment. Depending on the type of primer, the curing equipment may be an oven, such as a convection oven, an infrared (or near-infrared) oven, or an induction oven, a UV curing device, and / or an electron beam curing device.

[0103] The coil coating line 1 may further comprise an output accumulator 12 located in the output section of the line, downstream of the electron beam curing device. The output accumulator is similar to the input accumulator described above.

[0104] The coil coating line 1 may further comprise a coiling device 13 for coiling the strip that has been coated on the line. The coiling device may be combined with a cutting device to separate one strip from the next strip processed on the line.

[0105] The invention also relates to a gloss control tool for controlling the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip on a coil coating line 1 comprising, arranged sequentially along the path P of the moving strip S: a paint application device 2, a heating device 3 containing a heating module, an ultraviolet curing device 4 and an electron beam curing device 5.

[0106] The Gloss Control Tool contains a setting module for setting the target G value S gloss of the organic coating, given range R S gloss of the organic coating and the proportionality coefficient K in a predetermined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing.

[0107] The gloss control tool further comprises a data collection module configured to collect measurement data of the temperature T of the wet film at least in a section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device and to collect measurement data of the gloss G of the organic coating at least in a section of the width downstream of the electron beam curing device.

[0108] The gloss control tool further comprises a correction module configured to correct the deviation of the measured gloss G beyond a specified range R S gloss, while the correction includes the calculation of the corrected temperature T C, which the wet film must reach at least over a portion of the width of the moving strip downstream of the heating module and upstream of the UV curing device, in accordance with equation 1:

[0109] T C = T + K (G - G S ) (1)

[0110] and adjust the setting parameter of the coil coating line based on the calculated adjusted temperature T C .

[0111] The gloss control instrument may comprise a data processing unit formed, for example, by a memory module and a processor connected to the memory module. The electronic monitoring device may also comprise a display screen and input / output means, such as a keyboard and a mouse, each of which is connected to the data processing unit. Each module, including the setting module, data collection module, and adjustment module, may be implemented as software executed by the processor.

[0112] The coil coating line is preferably equipped with a gloss control tool to facilitate the gloss control on the coil coating line.

[0113] From a process perspective, gloss control of the organic coating formed by wet-film coating and curing of a radiation-curable paint on a moving strip in the above-described coil coating line is primarily based on the discovery that the wet-film temperature before ultraviolet curing plays a key role. Specifically, the inventors observed that, in dual-curing coil coating, a linear relationship exists between the wet-film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing. Therefore, any deviation in gloss after electron beam curing can be effectively and reproducibly corrected by adjusting the wet-film temperature before ultraviolet curing.

[0114] The method is applied to a moving strip. The strip may be a single roll unwound at the entrance of a coil coating line. More commonly, the strip consists of multiple rolls connected end to end. The rolls form a single, substantially continuous strip whose properties and specifications, to be achieved at the exit of the coil coating line, change over time. The strip moves along path P of the coil coating line so that a wet film of radiation-curable paint is applied, preferably heated, and cured twice.Specifically, the strip moves along path P of the coil coating line such that a wet film of radiation-curable paint is first applied to the strip by a paint applicator, then heated by a heating module, then exposed to UV radiation in an ultraviolet curing device, and finally cured in an electron beam curing device. Optionally, the strip can be preheated using an inductor 8 located upstream of the paint applicator 2. Optionally, the radiation-curable paint can be heated in the paint applicator.

[0115] The first embodiment of the method is described with reference to Fig. 2.

[0116] The first step of 100 gloss control method is to set the target values ​​required for proper adjustment.

[0117] Set the set value G first SOrganic coating gloss. This value corresponds to the gloss requested by the customer or the coil coating line operator. For practical purposes, it can be manually entered into the gloss management tool, specifically the installation module. Alternatively, it can be automatically retrieved from the coil coating line order book, specifically from the planning tool.

[0118] Since slight variations in gloss along the strip length are generally acceptable from a quality standpoint, a specified R range is also set S gloss of an organic coating. It can be entered directly as a range—minimum and maximum gloss—or it can be entered as a standard deviation from the specified gloss value Gs. Of course, if for some reason small deviations are unacceptable, the specified gloss value Gs Scan be entered as either the minimum or maximum gloss, or the standard deviation can be set to zero. From a practical standpoint, the specified range R S The gloss value can be manually entered into the gloss management tool, specifically the installation module. Alternatively, it can be automatically obtained from the coil coating line management tool or from the coil coating line order book, specifically from the planning tool. The specified range R S Gloss can also be obtained from standards such as EN10169:2013.

[0119] Also, since the gloss control is based on the linear mathematical relationship between the wet film temperature before UV curing and the gloss of the organic coating after electron beam curing, it is necessary to set the proportionality coefficient K in this linear mathematical relationship in order for the adjustment to be correct.

[0120] The proportionality factor K can be obtained during the calibration step performed before the installation step. During this calibration step, wet films of radiation-curable paint to be used on the coil coating line are heated at different temperatures, cured using dual curing under standard curing conditions, and the gloss of the organic coatings is measured. This allows the proportionality factor K to be derived. It is preferably expressed in °C / GU, °F / GU, or K / GU, depending on the temperature unit. This calibration step can be performed once and for all and does not need to be repeated each time the method according to the invention is implemented.

[0121] From a practical standpoint, the proportionality coefficient K is obtained from a predetermined linear mathematical relationship between the wet-film temperature before UV curing and the gloss of the organic coating after electron beam curing. This predetermined linear mathematical relationship is available to the coil coating line operator. Specifically, K is the proportionality coefficient in the linear mathematical relationship T = T0 - K G. By "predetermined" is meant that the calibration step, preferably as described above, was performed before implementing the method on the coil coating line. The proportionality coefficient K can be manually entered into the gloss control tool, particularly the installation module.Alternatively, it can be obtained automatically by matching pre-defined linear mathematical relationships entered into the gloss management tool, perhaps in a table, with a paint reference value from the coil coating line order book, in particular from a planning tool.

[0122] For example, it has been found that for commercially available radiation curable paints for steel coil coating, K is typically in the range of 0.3-1.2.

[0123] In the second step 120 of the gloss control method, the measurement data of the temperature T of the wet film is collected at least in a section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device, and the measurement data of the gloss G of the organic coating is collected at least in a section of the width downstream of the electron beam curing device.

[0124] Preferably, the temperature is measured using the wet film temperature measuring device as described above, and the gloss is measured using the gloss measuring device as described above.

[0125] Preferably, both measurements are performed at sufficiently short time intervals to ensure correct gloss control. Examples of time intervals: more often than every 30 seconds, 20 seconds, 10 seconds, 5 seconds, 2 seconds, or less than every second. More preferably, both measurements are continuous or substantially continuous. Preferably, both measurements are performed at sufficiently short time intervals to ensure correct gloss control. Examples of time intervals: more often than every 30 seconds, 20 seconds, 10 seconds, 5 seconds, 2 seconds, or less than every second. More preferably, both measurements are continuous or substantially continuous. Preferably, the measurement data is collected in the gloss control tool, in particular in the data collection module, more preferably automatically using an appropriate interface.

[0126] By "width section" is meant that the moving strip is conceptually divided into sections adjacent to each other across the width of the strip. There may be a single width section or multiple sections. Consequently, the wet film and organic coating may also be conceptually divided into the same width sections. By the phrase "at least a width section" is meant that the method is implemented either over a single width section, or over multiple width sections, or over the entire width of the moving strip. If it is not implemented over the entire width, data can be measured and collected for:

[0127] - the wet film temperature T over a single width section, if the measurement over that width section is considered to be reasonably representative of the average temperature over the entire width of the strip, or

[0128] - wet film temperature in several width sections so that the temperature in each width section can be controlled independently from other sections.

[0129] Similarly, data can be measured and collected on:

[0130] - the gloss G of the organic coating over one single width section, if the measurement over that width section is considered sufficiently representative to control the gloss of the entire strip width, or

[0131] - the shine of the organic coating in several width sections so that the shine in each width section can be adjusted independently from other sections.

[0132] In one embodiment, the data collection step is performed after the installation step.

[0133] In another embodiment, particularly during continuous operation of a coil coating line, the data collection step can be performed in parallel with the installation step. In this case of continuous operation, since the strip consists of different coils connected end to end, changes in strip properties and changes in strip specifications frequently occur. While the data collection step is in progress, any of the specified parameters, in particular any values ​​from the specified G value, S brightness, given range R S gloss and / or K-value may change for some reason, such as due to a change in said gloss or a change in the radiation-curable paint. Therefore, the installation stage is performed.

[0134] In the third step 130 of the gloss control method, the possible deviation of the measured gloss G beyond the specified range R is corrected Sgloss. First, the possible gloss deviation is estimated by comparing the measured gloss G with the specified gloss value G S and / or with a given range R S gloss. If the measured gloss value G is still within the specified range R S gloss, the settings are saved. If the measured gloss value G deviates outside the specified range R S gloss, the corrected temperature T is calculated C , which the wet film must reach at least over a portion of the width of the moving strip downstream of the heating module and upstream of the UV curing device, in accordance with equation 1:

[0135] T C = T + K (G - G S ) (1)

[0136] Gloss deviation evaluation can be performed at any time. Preferably, it is performed at sufficiently short time intervals to ensure correct gloss control. Examples of time intervals: more frequently than every 30 seconds, 20 seconds, 10 seconds, 5 seconds, 2 seconds, or less than every second. More preferably, the evaluation is continuous or substantially continuous.

[0137] After the corrected temperature has been calculated, the calculation result, i.e., the corrected temperature T C , preferably provided to the line operator, who can make any necessary adjustments.

[0138] In general, the line settings are adjusted based on the calculated corrected temperature T C, in order to obtain a gloss with a value of G on the organic coating at least in a section of the width of the moving strip downstream of the electron beam curing device SIn particular, the line settings are adjusted so that the wet film reaches the corrected temperature T C at least in the section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device.

[0139] In the first embodiment illustrated in Fig. 2, after the corrected temperature has been calculated, the power of the heating module is adjusted so that the wet film reaches the corrected temperature T Cat least over a section of the moving strip width downstream of the heating module and upstream of the UV curing device. Adjusting the heating module power involves turning the heating module on or off. By adjusting the heating module, the wet film temperature over a section of the width downstream of the heating module and upstream of the UV curing device is adjusted, and a gloss value of G is achieved on the organic coating over a section of the width downstream of the electron beam curing device. S The power adjustment of the heating module can be performed either manually by the operator or automatically using the gloss control tool, in particular the correction module.

[0140] Alternatively, in the case where the coil coating line is equipped with an inductor located upstream of the paint applicator, after the corrected temperature has been calculated, the power of the inductor is adjusted so that the strip temperature at the paint applicator level is adjusted so that the wet film reaches the corrected temperature T CAt least across the width of the moving strip downstream of the heating module and upstream of the UV curing unit. This alternative gloss adjustment method is particularly useful when the heating module is already operating at maximum power and the wet film temperature upstream of the UV curing unit needs to be further increased. Additional strip heating in the inductor reduces the required superheating provided by the heating module.

[0141] In one embodiment, the adjusting step 130 is performed after the data collection step 120.

[0142] In another embodiment, particularly during continuous operation of a coil coating line, the correction step can be performed in parallel with the data collection step. In continuous operation, since the strip consists of different coils connected end-to-end, changes in strip properties and strip specifications frequently occur. These changes can cause gloss to deviate from the specified value. While the data collection step is in progress, the correction step is performed to correct the measured gloss.

[0143] Optionally, the method further includes step 110, during which initial line conditions are established. This step is called the initial line setup step. As explained above, the method is such that any deviation of the measured gloss outside a predetermined range R is corrected. Sgloss. However, at the beginning of a production campaign on a coil coating line or after an important change, such as strip format, paint thickness, paint color, or line speed, line conditions may shift from those suitable for achieving the specified G value. S shine. In this case, the heating module may not perform heating properly and / or it may take some time to reach the power corresponding to the corrected temperature T C , and / or the power may not be sufficient for the wet film to reach the corrected temperature T CConsequently, a section of the coated strip may be rejected because the gloss does not meet the required specifications. Furthermore, the UV dose required to create a surface roughness that achieves the required gloss level may be inappropriate. In this case, the heating module must compensate for the deviation from the correct UV dose, possibly by applying more heat, which takes time. Here again, a section of the coated strip may be rejected because the gloss does not meet the required specifications. To minimize the length of the coated strip that does not meet the required specifications, it is useful to establish initial line conditions.

[0144] For this purpose, in the first sub-step, data on the process parameters and / or characteristics of the coated strip are collected. An example of a process parameter is the initial line speed LS0. Preferably, this is the line speed recommended for the next coil to be coated on the coil coating line. Another example is the initial thickness FTh0 of the wet film applied to the strip by the paint applicator. The initial film thickness is preferably one that corresponds to the thickness of the organic coating specified for the next coil to be coated on the coil coating line. Another example is the temperature of the moving strip in front of the paint applicator, preferably in front of the inductor. Examples of characteristics are the initial strip thickness STh0, the initial strip width SWd0, and the paint color.Preferably, data on the initial line speed LS0, initial thickness FTh0, initial strip thickness STh0, initial strip width SWd0, and paint color are collected. From a practical standpoint, process parameters and / or characteristics can be manually entered into the gloss management tool, in particular the installation module. Alternatively, they can be automatically retrieved from the coil coating line order book, in particular from the planning tool, and / or output from the order book. For example, the initial film thickness FTh0 can be derived from the organic coating thickness specified in the order book.

[0145] After the process parameter and / or characteristic data has been collected, the second sub-step involves setting the initial line conditions based on the collected process parameters and / or characteristics. Specifically, these initial line conditions are calculated based on the collected process parameters and / or characteristics. The following initial line conditions can be set:

[0146] - initial power PW0 of the heating module,

[0147] - the initial dose D0UV of the UV curing device or UV module, if used,

[0148] - the initial distance L0 between the UV curing device or UV module, if used, and the electron beam curing device.

[0149] The initial power PW0 can be set based on the mass flow rate of the moving strip, the strip's specific heat capacity, and the heating coefficient. The initial UV dose D0 can be set based on the data obtained during the calibration stage performed before the initial line setup. The initial distance L0 can be set based on the data obtained during the calibration stage performed before the initial line setup.

[0150] From a practical standpoint, the initial line conditions can be manually entered into the coil coating line management tool. Alternatively, they can be entered automatically using the gloss control tool in the coil coating line management tool.

[0151] In one embodiment, the initial line setup step 110 is performed before the setup step 100. This helps to start production with line conditions that are already optimized for the first roll of the production campaign, in addition to the initial combination of the set value G S brightness, given range R S gloss and K-factor. During production, a data collection step and an adjustment step can be performed to control gloss. When any of the specified parameters, in particular any parameter from the specified G-value S brightness, given range R Sgloss and / or K-factor, should be changed for some reason, for example, due to a change in said gloss or a change in radiation curing paint, then the capabilities of the data collection step 120 and the adjustment step 130 are used in order to keep the measured gloss within the specified range R S shine.

[0152] In another embodiment, the initial line setting step 110 is performed after the setting step 100, as illustrated in Fig. 2. Thus, the setting of the initial conditions of the line can be performed taking into account the specified value G S gloss. Line conditions are thus better optimized for the first roll of a production campaign. Moreover, during production, when any of the specified parameters, in particular any parameter from the specified gloss value G, the specified range R Sgloss and / or K-factor must be changed for some reason, the initial line settings can be reset to help minimize the transition period.

[0153] In another embodiment, the initial line setup step 110 is performed before and after the setup step 100 in order to take advantage of both of the above embodiments.

[0154] In another embodiment, particularly during continuous operation of a coil coating line, the line setup phase can be performed in parallel with the data collection phase. In this case of continuous operation, since the strip consists of different coils connected end-to-end, changes in strip properties and strip specifications frequently occur. Re-initializing the line conditions when one of these changes occurs helps achieve the specified gloss value as quickly as possible.

[0155] Next, a second embodiment of the method is described with reference to Fig. 3.

[0156] This embodiment differs from the first mainly in that the adjusting step includes additional sub-steps for:

[0157] - ensuring that the calculated corrected temperature T C did not exceed the maximum temperature T max which could cause degradation of the radiation cured paint, and

[0158] - the corresponding correction of the deviation of the measured gloss value G.

[0159] Thanks to this configuration, the method additionally prevents thermal degradation of the wet film when heated in the heating module.

[0160] The details provided in the description of the first embodiment apply to the second embodiment. Additional steps and corresponding features are described in detail below.

[0161] Step 100 of the installation additionally includes setting the maximum temperature T max for radiation-curing paint. This temperature may be recommended by the paint supplier. Alternatively, it can be determined by the coil coating line operator, in particular by measuring paint monomer evaporation as a function of temperature, which is measured offline or, possibly, in real time, at the heating module level. From a practical standpoint, the maximum temperature T max can be manually entered into the gloss management tool, specifically the installation module. Alternatively, it can be determined automatically by comparing various maximum temperature values ​​entered into the gloss management tool with paint reference values ​​from the line order book, specifically from the planning tool.

[0162] Step 120 data collection further includes collecting data on the UV dose D of the UV module. The UV module power is typically known to the operator, perhaps from the roll coating line control instrument, but for a given power, the actual UV dose to which the wet film is exposed varies with the line speed L. S Accordingly, the UV dose is calculated based on the UV module power and line speed and stored in the system. The line speed itself is typically known to the operator, perhaps from a coil coating line control system.

[0163] Preferably, the UV dose is recalculated and stored in the system each time the UV module power and / or line speed are adjusted. More preferably, UV dose data collection is substantially continuous. Preferably, UV dose data is collected in the gloss management tool, particularly in the data collection module, preferably automatically via an appropriate interface.

[0164] At the adjustment step 130, after the adjusted temperature T C was calculated, it is compared with the maximum temperature T max . If the value of T C below the value of T max , then the power of the heating module is adjusted so that the wet film reaches the adjusted temperature T Cat least over a section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device, as in the first embodiment. Alternatively, in the case where the coil coating line is equipped with an inductor upstream of the paint applicator, after the corrected temperature has been calculated, the power of the inductor is adjusted such that the strip temperature at the level of the paint applicator is adjusted such that the wet film reaches the corrected temperature T C at least in the section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device.

[0165] If the value of T C exceeds the value T max, then the gloss should be adjusted without further increasing the power of the heating module or the power of the inductor. One way to achieve this is to adjust, in particular increase, the power of the UV module. Indeed, it has been observed that this affects the gloss of the organic coating. The higher the UV dose on the wet film, the lower the gloss. Therefore, the adjustment step 130 additionally includes calculating the adjusted dose D C The UV radiation to which the wet film must be exposed over at least the width of the moving strip in the UV module, according to equation 2:

[0166] D C = f1(D, G, G S ) (2)

[0167] Equation (2) can be obtained in a calibration step performed before the adjustment step, preferably before the setup step. During this calibration step, wet films of radiation-curable paint to be used on a coil coating line are exposed to different doses of UV radiation, cured with an electron beam under standard curing conditions, and the gloss of the organic coating is measured. Thus, the function f1 can be derived for each radiation-curable paint. This calibration step can be performed once and for all, and does not need to be performed each time the method according to the invention is implemented.

[0168] Preferably, function f1 of the predetermined mathematical relationship between the UV dose to which the wet film of the radiation-curable paint is exposed and the gloss of the organic coating after electron beam curing is established during the setup step. The term "predetermined" means that the calibration step, preferably as described above, was performed before implementing the method on the coil coating line. Function f1 can be manually entered into the gloss management tool, in particular the setup module. Alternatively, it can be obtained automatically by comparing the predetermined mathematical relationships entered into the gloss management tool with the paint reference values ​​from the coil coating line order book, in particular from the planning tool.

[0169] For example, it has been found that for commercially available radiation-curable paints intended for coating steel coil, the f1 function typically follows a gloss curve that decreases with increasing UV dose and tends to an asymptote.

[0170] After the adjusted UV dose has been calculated, the calculation result, i.e., the adjusted dose D C UV radiation is preferably provided to the line operator, who can make any necessary adjustments.

[0171] In general, the line settings that are different from the power of the heating module and different from the power of the inductor, if used, are adjusted based on the calculated adjusted dose D C UV radiation to achieve a gloss of G value on the organic coating at least over a section of the width of the moving strip downstream of the electron beam curing device. S .

[0172] In the embodiment illustrated in Fig. 3, after the adjusted UV dose has been calculated, the power of the UV module is adjusted, in particular, increased so that the wet film at least in a portion of the width of the moving strip is exposed to the dose D C UV radiation in the UV module. By adjusting the UV module, the UV dose to which the wet film is exposed in the width section of the UV module is adjusted, resulting in a G-value gloss on the organic coating in the width section downstream of the electron beam curing unit. S The UV module power can be adjusted either manually by the operator or automatically using the gloss control tool.

[0173] Next, a third embodiment of the method is described with reference to Fig. 4.

[0174] This embodiment differs from the second one mainly in that the adjusting step includes additional sub-steps for:

[0175] - ensuring that the calculated adjusted dose D C UV radiation did not exceed the maximum dose D max UV radiation to which the wet film may be exposed,

[0176] - the corresponding correction of the deviation of the measured gloss G.

[0177] By this configuration, the method further prevents excessive curing of the wet film in the UV curing device, which may adversely affect the gloss.

[0178] The details provided in the description of the first and second embodiments apply to the third embodiment. Further steps and corresponding features are described in detail below.

[0179] In this embodiment, the UV module of the ultraviolet curing device of the coil coating line can move along the trajectory P. Accordingly, the distance L between the UV module and the electron beam curing device can be adjusted.

[0180] Step 100 of the installation further includes setting the maximum dose D max The UV radiation to which the wet film can be exposed in the UV module. This UV dose may be recommended by the paint supplier. Alternatively, it can be determined by the coil coating line operator, particularly during the calibration stage. From a practical standpoint, the maximum dose D maxUV radiation can be manually entered into the gloss management tool, specifically the installation module. Alternatively, it can be generated automatically by comparing the various maximum UV doses entered into the gloss management tool with the paint reference values ​​in the coil coating line order book, specifically the planning tool.

[0181] Data collection step 120 further includes collecting data on the distance L between the UV module and the electron beam curing device. This distance is typically known to the operator, possibly from a coil coating line control tool. This data can be collected manually. Preferably, it is collected in a gloss control tool, more preferably automatically via an appropriate interface. Preferably, it is collected only when the distance L changes.

[0182] At the adjustment step 130, after the adjusted dose D CUV radiation was calculated and compared with the maximum dose D max UV radiation. If the D value C below the value of D max , then the power / settings of the UV module are adjusted in such a way that the wet film at least over a section of the width of the moving strip is exposed to a dose of D C UV radiation in the UV module. By adjusting the UV module, the UV dose to which the wet film is exposed in the width section of the UV module is adjusted, resulting in a G-value gloss on the organic coating in the width section downstream of the electron beam curing unit. S , as in the second embodiment.

[0183] If the value of D C exceeds the value of D max, then the gloss should be adjusted without further increasing the UV dose of the UV module. One way to achieve this is to adjust, specifically increase, the distance between the UV module and the electron beam curing device. Indeed, this has been found to affect the gloss of the organic coating. The longer the time between UV curing and electron beam curing, the lower the gloss. Therefore, adjustment step 130 further includes calculating the adjusted distance L. C between the UV module and the electron beam curing device, according to equation 3:

[0184] L C = f2(L, G, G S ) (3)

[0185] Equation (3) can be obtained in a calibration step performed before the adjustment step, preferably before the installation step. In this calibration step, wet films of the radiation-curable paint to be used on the coil coating line are sequentially cured by UV and electron beam under standard curing conditions with different times between the two curing processes, and the gloss of the organic coating is measured. Thus, the function f2 can be derived for each radiation-curable paint. This calibration step can be performed once and for all, and does not need to be performed each time the method according to the invention is implemented.

[0186] Preferably, the function f2 of the predetermined mathematical relationship between the distance from the UV module to the electron beam curing device and the gloss of the organic coating after electron beam curing is established during the setup stage. By "predetermined" is meant that the calibration stage, preferably as described above, was performed before implementing the method on the coil coating line. The function f2 can be manually entered into the gloss management tool, in particular the setup module. Alternatively, it can be obtained automatically by comparing the predetermined mathematical relationships entered into the gloss management tool with the paint reference values ​​from the coil coating line order book, in particular from the planning tool.

[0187] For example, it has been found that for radiation-curable paints commercially available for coil coating, the f2 function is typically described by a light curve that decreases with increasing L and tends to an asymptote.

[0188] After the adjusted distance has been calculated, the calculation result, i.e. the adjusted distance L C , preferably provided to the line operator, who can make any necessary adjustments.

[0189] In general, the line settings, which are different from the power of the heating module and different from the power of the inductor, if used, and different from the power of the UV module, are adjusted taking into account the calculated adjusted distance L C in such a way that a gloss with a value of G is obtained on the organic coating at least in a section of the width of the moving strip downstream of the electron beam curing device S .

[0190] In the embodiment illustrated in Fig. 4, after the adjusted distance has been calculated, the distance between the UV module and the electron beam curing device is adjusted, in particular, increased, so that a gloss with a G value is obtained on the organic coating at least in a portion of the width of the moving strip downstream of the electron beam curing device. S Distance adjustment can be performed either manually by the operator or automatically using the gloss control tool.

[0191] Alternatively, particularly if the distance between the UV module and the electron beam curing device cannot be further increased or decreased, the line speed can be adjusted. In this case, the initial line setup can be performed again to adjust the initial power PW0 of the heating module, the initial UV dose D0 of the UV curing device, and the initial distance L0 between the UV curing device and the electron beam curing device according to the new line speed.

[0192] The invention also relates to a method for forming an organic coating on a moving strip on a coil coating line comprising, arranged sequentially along the path P of the moving strip: a paint application device, a heating device containing a heating module, an ultraviolet curing device and an electron beam curing device, wherein the method includes the steps of:

[0193] - applying a wet film of radiation-curable paint to a moving strip using a paint application device,

[0194] - heating a wet film of radiation-curable paint in a heating module,

[0195] - the effect of UV radiation on a wet film of radiation-curable paint in an ultraviolet curing device,

[0196] - curing a wet film of radiation-curable paint in an electron beam curing device to form an organic coating,

[0197] The gloss of the organic coating is adjusted by:

[0198] - setting the set value G S gloss of the organic coating, given range R S gloss of the organic coating and the proportionality coefficient K in a predetermined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing,

[0199] - collecting data on measuring the temperature T of the wet film at least in a section of the width of the moving strip upstream of the ultraviolet curing device and collecting data on measuring the gloss G of the organic coating at least in a section of the width downstream of the electron beam curing device,

[0200] - correction of the deviation of the measured gloss G beyond the specified range R Sgloss, and this stage of correction includes a sub-stage of calculating the corrected temperature T C , which the wet film must reach at least in the width section upstream of the UV curing device, according to equation 1:

[0201] T C = T + K (G - G S ) (1)

[0202] All the details provided regarding the gloss control method and all the details provided regarding the coil coating line are applicable to the organic coating formation method.

[0203] The invention also relates to a method for producing a pre-painted metal containing a metal strip and an organic coating on a coil coating line comprising, arranged sequentially along the path P of the moving metal strip: a paint application device, a heating device containing a heating module, an ultraviolet curing device and an electron beam curing device, wherein the method includes the steps of:

[0204] - applying a wet film of radiation-curable paint to a moving metal strip using a paint application device,

[0205] - heating a wet film of radiation-curable paint in a heating module,

[0206] - the effect of UV radiation on a wet film of radiation-curable paint in an ultraviolet curing device,

[0207] - curing a wet film of radiation-curable paint in an electron beam curing device to form an organic coating,

[0208] The gloss of the organic coating is adjusted by:

[0209] - setting the set value G S gloss of the organic coating, given range R S gloss of the organic coating and the proportionality coefficient K in a predetermined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing,

[0210] - collecting data on measuring the temperature T of the wet film at least in a section of the width of the moving strip upstream of the ultraviolet curing device and collecting data on measuring the gloss G of the organic coating at least in a section of the width downstream of the electron beam curing device,

[0211] - correction of the deviation of the measured gloss G beyond the specified range R S gloss, and this stage of correction includes a sub-stage of calculating the corrected temperature T C , which the wet film must reach at least in the width section upstream of the UV curing device, according to equation 1:

[0212] T C = T + K (G - G S ) (1)

[0213] All the details provided regarding the gloss control method and all the details provided regarding the coil coating line are applicable to the production method of pre-painted metal.

Claims

1. A method for controlling the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip on a coil coating line comprising, arranged sequentially along the path P of the moving strip: a device for applying paint, a heating device containing a heating module, an ultraviolet curing device and an electron beam curing device, comprising the steps of: - set the specified value of G S gloss of organic coating, specified range R S gloss of the organic coating and the proportionality coefficient K in a predetermined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing; - collecting data on the measurement of the temperature T of the wet film over at least a section of the width of the moving strip upstream of the ultraviolet curing device and collecting data on the measurement of the gloss G of the organic coating over at least said section of the width downstream of the electron beam curing device; - correct the deviation of the measured gloss G beyond the specified range R S shine, and at this stage of correction a sub-stage is performed in which the corrected temperature T is calculated C , which the wet film must reach at least in the width section upstream of the UV curing device, in accordance with equation (1) T C = T + K (G - G S ), (1) and a sub-stage in which the setting parameter of the rolled metal coating line is adjusted taking into account the calculated corrected temperature T C .

2. The method according to claim 1, wherein the heating device does not comprise an infrared heater.

3. The method according to claim 1, wherein the heating device is selected from an induction heater, a convector, a forced air heater, a water spray heater, an air-water mist heater, and a heated roller.

4. The method according to any one of paragraphs 1-3, which also comprises a step of initial line setup, in which: - collect data on process parameters and / or strip characteristics; - at least one initial line condition is established from the initial power PW0 of the heating module, the initial dose D0 of UV radiation of the ultraviolet curing device and the initial distance L0 between the ultraviolet curing device and the electron beam curing device taking into account the collected process parameters and / or strip characteristics.

5. The method according to any one of paragraphs 1-4, in which at the sub-step of adjusting the setting parameter of the coil coating line, the power of the heating module is adjusted so that the wet film reaches the adjusted temperature T C at least in the section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device.

6. The method according to any one of paragraphs 1-4, in which the coil coating line further comprises an inductor upstream of the paint application device, wherein at the sub-step of adjusting the setting parameter of the coil coating line, the power of the inductor is adjusted so that the wet film reaches the adjusted temperature T C at least in the section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device.

7. The method according to any one of paragraphs 1-4, in which: - the ultraviolet curing device contains a UV module; - at the installation stage, the maximum temperature T is additionally set max for radiation-curing paint; - at the data collection stage, additional data on the dose D of UV radiation from the UV module is collected; - at the sub-stage of adjusting the setting parameter of the rolled metal coating line evaluate whether the value T exceeds C value of T max , If not, adjust the power of the heating module so that the wet film reaches the corrected temperature T C at least in the section of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device, if the value of T C exceeds the value T max : calculate the adjusted dose DC UV radiation to which the wet film must be exposed over at least a width section in the UV module, according to equation (2) D C = f1(D, G, G S ), (2) adjust the setting parameter of the rolled metal coating line, which is not the power of the heating device, taking into account the calculated adjusted dose D C UV radiation.

8. The method according to claim 7, in which, at the sub-step of adjusting the setting parameter of the coil coating line, which is not the power of the heating module, the power of the UV module is adjusted in such a way that the wet film at least in a section of the width of the moving strip is exposed to the adjusted dose D C UV radiation.

9. The method according to paragraph 7, wherein: - The UV module is movable along the path P; - at the installation stage, the maximum dose D is additionally set maxUV radiation to which the wet film in the UV module may be exposed; - at the data collection stage, additional data is collected on the distance L between the UV module and the electron beam curing device; - at the sub-stage of adjusting the setting parameter of the rolled metal coating line, which is not the power of the heating module, evaluate whether the value of D exceeds C value D max , if not, adjust the power of the UV module so that the wet film over at least a portion of the width of the moving strip is exposed to the adjusted dose D C UV radiation, if the value of D C exceeds the value of D max : calculate the adjusted distance L C between the UV module and the electron beam curing device in accordance with equation (3) L C = f2(L, G, G S ), (3) adjust the installation parameter of the coil coating line, which is not the power of the heating module and is not the power of the UV module, taking into account the calculated adjusted distance L C .

10. The method according to claim 9, in which, at the sub-step of adjusting the setting parameter of the coil coating line, which is not the power of the heating module and is not the power of the UV module, the distance between the UV module and the electron beam curing device is adjusted to the adjusted distance L C in such a way that a gloss with a value of G is obtained on the organic coating at least in a section of the width of the moving strip downstream of the electron beam curing device S .

11. A coil coating line comprising a sequentially arranged paint application device, a heating device comprising a heating module, an ultraviolet curing device and an electron beam curing device, wherein the coil coating line also comprises a gloss control tool for controlling the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip on the coil coating line, wherein the gloss control tool comprises: - a setting module configured to set a given gloss value G S organic coating, specified range R Sgloss of the organic coating and the proportionality coefficient K in a predetermined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing; - a data collection module configured to collect data on the measurement of the temperature T of the wet film at least in a section of the width of the moving strip upstream of the ultraviolet curing device and to collect data on the measurement of the gloss G of the organic coating in at least said section of the width downstream of the electron beam curing device; - a correction module designed with the ability to correct the deviation of the measured glare G beyond a specified range R S gloss, while the correction includes the calculation of the corrected temperature T C, which the wet film must reach at least in the width section upstream of the UV curing device, in accordance with equation (1) T C = T + K (G - G S ) (1) and adjustment of the installation parameter of the rolled metal coating line taking into account the calculated corrected temperature T C .

12. A coil coating line according to claim 11, wherein the heating device does not contain an infrared heater.

13. A coil coating line according to claim 11, wherein the heating device is selected from an induction heater, a convector, a forced air heater, a water spray heater, an air-water mist heater, and a heated roller.

14. A method for forming an organic coating on a moving strip on a coil coating line comprising, sequentially arranged along the path P of the moving strip: a device for applying paint, a heating device containing a heating module, an ultraviolet curing device and an electron beam curing device, comprising the steps of: - apply a wet film of radiation-curable paint to a moving strip using a paint application device; - heat the wet film of radiation-curable paint in a heating module; - act on a wet film of radiation-curable paint with UV radiation in an ultraviolet curing device; - harden a wet film of radiation-curable paint in an electron beam curing device to form an organic coating, in this case, to adjust the gloss of the organic coating: - set the specified value Gs of the organic coating gloss, the specified range R S gloss of the organic coating and the proportionality coefficient K in a predetermined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing; - collecting data on the temperature T of the wet film over at least a portion of the width of the moving strip upstream of the ultraviolet curing device and collecting data on the gloss G of the organic coating over at least a portion of the width downstream of the electron beam curing device; - correct the deviation of the measured gloss G beyond the specified range R S shine, and at this stage of the correction, the sub-stage of calculating the corrected temperature T is performed C, which the wet film must reach at least in the width section upstream of the UV curing device, in accordance with equation (1) T C = T + K (G – G S ) (1) and a sub-stage of adjusting the setting parameter of the rolled metal coating line taking into account the calculated corrected temperature T C .

Images