METHOD FOR MANAGING THE GLOSS OF AN ORGANIC COATING AND COATING LINE ON A COIL

Description

1 / 47 “METHOD FOR MANAGING THE GLOSS OF AN ORGANIC COATING AND COATING LINE ON A COIL” Field of invention

[001] 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. In particular, the moving strip is a steel strip with a metallic coating. Background of the Invention

[002] Coil coating is a continuous, automated process for coating metals prior to manufacturing into finished products. The steel or aluminum substrate is delivered in coil form from the rolling mills. The metal coil is positioned at the beginning of the coil coating line and, in a continuous process, the coil is unwound, pre-cleaned, pre-treated, pre-primed, and pre-painted before being rewound at the other end and packaged for shipment.

[003] The product obtained by this process is a pre-painted metal, also known as coil-coated metal, pre-finished metal, or pre-coated metal. It is commonly used in construction applications as well as in household appliances.

[004] The inks traditionally used for coil coating are solvent-based inks. However, there has been recent interest in radiation curing, which is the curing of materials using ultraviolet (UV processes) or electron beam (EB curing processes). The corresponding inks, known as energy-cured inks, are solvent-free, and the curing process is triggered by exposure to high-energy UV light, possibly in conjunction with suitable photoinitiators, or by exposure to accelerated electrons. The photoinitiators absorb UV light and generate free radicals. These react with double bonds of monomers, Petition 870250099327, dated 10 / 30 / 2025, page 10 / 120 2 / 47 causing a chain reaction and polymerization. For UV-C and electron beam (EB) curing, initiators are not required. The high radiant energy produces enough reactive species (radicals) for polymerization to occur spontaneously.

[005] One of the specificities of energy-cured paints is that they generate organic coatings with high gloss due to the high surface tension of the coating. To reduce this gloss and meet the requirements of the pre-painting market (gloss typically between 15 and 30 GU for the construction market), paint suppliers add matting agents, as is the case with solvent-based paints. However, since energy-cured paints are quite viscous due to the absence of solvent, only small amounts of matting agent can be added, which does not allow for low gloss levels. Furthermore, the migration of matting agents to the coating surface to achieve the desired gloss level is also very limited due to the speed of the curing process of energy-cured paints compared to solvent-based paints (12 seconds versus 12-25 seconds).

[006] One way to mitigate this problem is known from document WO81 / 00683, which describes a curing process in which the coating is first irradiated with curing radiation at wavelengths to which the coating responds, but without substantial distribution below about 300 nm (such as UV), and subsequently irradiated with curing radiation at wavelengths to which the coating responds, including substantial radiation at wavelengths below 300 nm (such as EB). This double curing is known as double curing. Gloss control is achieved by adjusting parameters online, including the spectral distribution, the intensity or dose of the initial radiation, or the time interval between the initial and subsequent irradiation steps. Petition 870250099327, dated 10 / 30 / 2025, page 11 / 120 3 / 47

[007] However, it was observed that these online parameters are not sufficient to manage brightness efficiently and reproducibly. Brief Description of the Invention

[008] The objective of the present invention is, therefore, to remedy the disadvantages of the prior art process by providing a method for efficiently and reproducibly managing the gloss of an organic coating formed by applying and curing a wet film of energy-cured ink on a moving strip in a coil coating line.

[009] To that end, a first object of the present invention consists of a method for managing the gloss of an organic coating formed by applying and curing a wet film of radiant-curing ink on a moving strip in a coil coating line, comprising, sequentially along the path (P) of the moving strip, an ink applicator, a heating device comprising a heating module, an ultraviolet curing device and an electron beam curing device, the method comprising the steps of: - Define a defined gloss value (Gs) for the organic coating and a defined gloss range (Rs) for the gloss of the organic coating. - Collect the gloss (G) measurement of the organic coating on at least one width portion downstream of the electron beam curing device. - Correcting a deviation of the measured brightness (G) beyond the defined brightness range (Rs), this correction step comprising a sub-step of calculating the correction (CP) to be applied to the power of the heating module, taking into account (Gs) and the measured brightness (G), with a closed-loop controller and a sub-step of adjusting a coil coating setting in line, taking into account the calculated correction (CP). Petition 870250099327, dated 10 / 30 / 2025, page 12 / 120 4 / 47

[010] The method according to the invention may also have the optional features listed below, considered individually or in combination: The closed-loop controller is a proportional-integral-derivative controller. - the correction (CP) is a function of the difference between (Gs) and the measured brightness (G), - The correction (CP) to be applied to the heating module power is calculated according to equation 1: CP(t) = Kpei(t) + KtJ0 ei(τ)άτ -^^- (1) where Kp is the proportional gain, Ki is the integral gain, Kd is the derivative gain and e1 is the difference between (Gs) and the measured brightness (G).

[011] The method also includes an initial line adjustment step in which: • A plurality of process parameters and / or strip specifications are collected, • At least one initial line condition between the initial power PW0 of the heating module, the initial UV dose D0 of the ultraviolet curing device, and the initial length L0 between the ultraviolet curing device and the electron beam curing device is defined, taking into account the process parameters and / or strip specifications that were collected, - the collection stage also includes collecting the temperature (T) measurement of the wet film in at least one portion of the width of the moving strip upstream of the ultraviolet curing device, - The correction stage also includes a sub-stage for calculating the corrected temperature (Tc) to be reached by the wet film, in at least a portion of the width downstream of the heating module and upstream of the Petition 870250099327, dated 10 / 30 / 2025, page 13 / 120 5 / 47 ultraviolet curing device, - the corrected temperature (Tc) is calculated according to the equation 2: Tc = f1 (T, G, Gs) (2) where the function (f1) is a predefined mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing, - The corrected temperature (Tc) is calculated according to equation 3: Tc = T + K (G - Gs) (3) - the correction (CP) is a function of the difference between (Tc) and the measured temperature (T), - The correction (CP) to be applied to the heating module power is calculated according to equation 4: CP(t) = K'pe2(t) + K'tJ0 β2(τ)άτ + K'di-~- (4) where K'p is the proportional gain, K'i is the integral gain, K'd is the derivative gain and e2 is the difference between (Tc) and the measured temperature (T); - the sub-step of adjusting a coil coating line configuration comprises adjusting the heating module power by correction (CP), - The ultraviolet curing device comprises a UV module, The adjustment stage also includes setting a maximum temperature, Tmax, for the UV curing ink. - the collection stage also includes collecting the UV dose (D) from the UV module, - The sub-step of adjusting a coil coating line configuration comprises: • Assess whether Tc is greater than Tmax, Petition 870250099327, dated 10 / 30 / 2025, page 14 / 120 6 / 47 • Otherwise, adjust the heating module power using the correction (CP), • If Tc is greater than Tmax: □ Calculate the correction (CD) to be applied to the UV dose to which the wet film, at least partly in width, must be exposed in the UV modulus, according to equation 5: CD = f2 (G, Gs) (5) □ adjustment of a coil coating line configuration different from the heating module power, taking into account the calculated correction (CD), - The sub-step of adjusting a coil coating line configuration, other than the heating module power, comprises adjusting the UV module power so that the wet film in at least a portion of the moving strip width is exposed to the corrected UV dose Dc = D + CD, - the UV module is mobile along the path (P), The adjustment step also includes setting a maximum UV dose, Dmax, to which the wet film can be exposed in the UV module. - the collection stage also includes collecting the length (L) between the UV module and the electron beam curing device, - The sub-step of adjusting a coil coating line configuration, other than the heating module power, comprises: - Assess whether D + CD is greater than Dmax, Otherwise, adjust the UV module power so that the wet film in at least a portion of the width of the moving strip is exposed to the corrected UV dose Dc = D + CD. - If D + CD is greater than Dmax: Petition 870250099327, dated 10 / 30 / 2025, page 15 / 120 7 / 47 • Calculate the correction (CL) to be applied to the length between the UV module and the electron beam curing device, according to equation 6: CL = f3 (G, Gs) (6) • adjustment of a coil coating line configuration different from the heating module power and UV module power, taking into account the calculated correction (CL), - The sub-step of adjusting a coil coating line configuration different from the heating module power and the UV module power comprises adjusting the length between the UV module and the electron beam curing device to the corrected length Lc = L + CL, so that the gloss value (Gs) is obtained in the organic coating in at least a portion of the width of the moving strip downstream of the electron beam curing device.

[012] A second object of the invention consists of a coil coating line comprising sequentially an ink applicator, a heating device comprising a heating module, an ultraviolet curing device and an electron beam curing device, the coil coating line further comprising a gloss management tool for managing the gloss of an organic coating formed by applying and curing a wet film of an energy-cured ink on a moving strip in the coil coating line, the gloss management tool comprising: - a configuration module that defines a defined gloss value (Gs) for the organic coating and a defined gloss range (Rs) for the organic coating gloss, - an acquisition module that collects gloss (G) measurements of the organic coating over at least a downstream width portion of the Petition 870250099327, dated 10 / 30 / 2025, page 16 / 120 8 / 47 electron beam healing device, - a correction module that corrects a deviation of the measured brightness (G) beyond the defined brightness range (Rs), the correction comprising a sub-step of calculating the correction (CP) to be applied to the power of the heating module, taking into account (Gs) and the measured brightness (G), with a closed-loop controller and a sub-step of adjusting a coil coating line configuration, taking into account the calculated correction (CP).

[013] Other features and advantages of the invention will be described in greater detail in the following description. Brief Description of the Figures

[014] The invention will be better understood by reading the following description, provided for explanatory purposes only and not intended in any way to be restrictive, with reference to: Figure 1, which is a schematic representation of a coiled coating line, Figure 2, which is a flowchart of a first embodiment of the method according to the invention, Figure 3, which is a flowchart of a second embodiment of the method according to the invention, Figure 4, which is a flowchart of a third embodiment of the method according to the invention. Detailed Description of the Invention

[015] It should be noted that spatially relative terms, such as upstream, downstream, lower, upper, above, below, before, after... as used in this application, refer to the positions and orientations of the different constituent elements of the coiled sheathing line. Petition 870250099327, dated 10 / 30 / 2025, page 17 / 120 9 / 47

[016] The method according to the invention is intended for strips, such as metal strips. Steel, whether carbon steel or stainless steel, aluminum and copper are examples of metal strips. In particular, steel strips can be bare or coated with a metallic coating on one or both sides of the strip.Examples of possible steels with metallic coating are galvanized steel, steels coated with a zinc alloy comprising 5% by weight of aluminum (Galfan®), steels coated with a zinc alloy comprising 55% by weight of aluminum, about 1.5% by weight of silicon, the remainder consisting of zinc and unavoidable impurities due to processing (Aluzinc®, Galvalume®), steels coated with an aluminum alloy comprising 8 to 11% by weight of silicon and 2 to 4% by weight of iron, the remainder consisting of aluminum and unavoidable impurities due to processing (Alusi®), steels coated with a layer of aluminum (Alupur®), steels coated with a zinc alloy comprising 0.5 to 20% aluminum, 0.5 to 10% magnesium, the remainder consisting of zinc and unavoidable impurities due to processing, steels coated with an alloy comprising aluminum, magnesium, silicon, Possible additional elements, the remainder consisting of zinc and unavoidable impurities due to processing.

[017] The method according to the invention also applies to dual-cure inks. The term dual-cure inks refers to radiation-curable compositions that are cured, or dried, using short-wavelength ultraviolet (UV) light and / or high-energy electrons from electron beam (EB) sources. They generally comprise liquid monomers and oligomers in which pigments, fillers, additives, and photoinitiators can be dispersed, generally without the need for solvent or water. Therefore, they are substantially solvent-free. Dual-cure inks preferably comprise acrylate or methacrylate monomers and photoinitiators.

[018] With reference to Figure 1, the coating line in Petition 870250099327, dated 10 / 30 / 2025, page 18 / 120 10 / 47 coil (1), according to the invention, comprises mainly, sequentially along the path (P) of the moving strip, an ink applicator (2), a heating device (3) comprising a heating module, an ultraviolet curing device (4) and an electron beam curing device (5).

[019] The path (P) is the route followed by the strip S from its entry into the coil coating line to its exit. It has a width and a length. Equipment is positioned along this path to perform operations on the strip.

[020] An ink applicator (2) is a device that applies a wet ink film to one or both sides of a strip with a defined ink thickness. In particular, its purpose is to apply the energy-cured wet ink film. In the context of the invention, the ink applicator technology is not limited.

[021] According to a variant of the invention, the paint applicator (2) is a paint roller applicator. This is an automated machine that coats one or both sides of a strip with rotating rollers. It is designed so that the strip passes through the machine which applies a layer of paint to one or both sides of the strip. There are several models of paint roller applicators, depending on the configuration of the coil coating line, the types of paint used and the types of strips to be coated. The specialist in the field will know which model is most suitable for each case. In general terms, the paint roller applicator comprises a paint tray, a steel or ceramic collector roller and a rubber-coated coating roller. The paint tray is intended to contain, circulate and preferably heat the paint.The pickup roller can be partially immersed in the ink and can rotate clockwise or counterclockwise to collect the ink and transfer it to the coating roller. The latter transfers the ink to the strip. Petition 870250099327, dated 10 / 30 / 2025, p. 19 / 120 11 / 47

[022] According to another variant of the invention, the paint applicator (2) is a curtain applicator. In this case, a curtain of paint is applied to the horizontal strip normally transverse to the curtain. The paint falls from a height, under the action of gravity, from a curtain or cascade matrix, while the strip is supported on a support roller. This method is capable of achieving high line speeds and multilayer coatings.

[023] Examples of other paint applicators are the knife applicator, the dip or meniscus applicator, the slot applicator, the rod applicator and the slide applicator.

[024] The paint is generally applied with the paint applicator across the entire width of the strip. By default, the width of the wet paint film and, consequently, of the organic coating, is equal to the width of the strip.

[025] The paint applicator (2) is preferably equipped with at least one paint heating device suitable for heating and maintaining the paint at a defined temperature. Heating the paint facilitates its application. It also further facilitates gloss management as it minimizes energy requirements at the heating module level and therefore minimizes heating module inertia. In the case of a paint roller applicator, the paint heating device may be a pan heater, i.e., a heater positioned within or around the paint pan. It may also be a temperature-controlled roller, in particular a temperature-controlled pickup roller, possibly in combination with the pan heater. In the case of a curtain applicator, the paint heating device may be a heater positioned upstream of the curtain matrix.It could also be a temperature-controlled support roller, possibly in combination with the heater.

[026] The paint applicator (2) is preferably equipped with a temperature measuring device to measure the temperature of the paint and / or Petition 870250099327, dated 10 / 30 / 2025, p. 20 / 120 12 / 47 the temperature of the wet film at the level of the paint applicator. The temperature device can be, for example, a temperature sensor, a pyrometer, or a thermal camera.

[027] The coil coating line (1) further comprises a heating device (3), which comprises a heating module, positioned along the path (P) of the moving strip, downstream of the ink applicator (2) and upstream of the ultraviolet (UV) curing device (4). Its purpose is to heat the wet film of the energy-cured ink. The heating device further improves the temperature control of the wet ink film before its surface is cured in the UV curing device. As the temperature of the strip exiting the ink applicator decreases at a rate that depends on several parameters (nature of the strip, width of the strip, thickness of the strip, line speed...), the temperature of the wet film entering the UV curing device can vary significantly from time to time, which would impair gloss. Thanks to the heating device, the temperature of the wet film can be adjusted very quickly.

[028] The heating device is preferably chosen from among an infrared heater, an induction heater, a convector, a forced-air heater, a water spray heater, a water-air mist spray heater, and a heated roller. Preferably, the heating device is an infrared heater. In the case of water-based heaters, as the wet film of energy-cured ink is applied to the top of the strip, the water is preferably placed in contact only with the back of the strip.

[029] According to one variant, the heating device consists of a heating module that covers the entire width of the path (P) of the moving strip. In this case, the wet film is heated uniformly along its width as it passes (through) the heating device. Petition 870250099327, dated 10 / 30 / 2025, p. 21 / 120 13 / 47

[030] According to another variant, the heating device (3) comprises a plurality of heating modules distributed along the width of the path (P). In other words, the plurality of heating modules forms a row substantially parallel to the width of the path (P), that is, perpendicular to the direction of movement of the strip. For clarity, the heating modules described here are independent of each other and positioned adjacent, but may be physically inseparable. They may be individually controllable parts of a single heating device.

[031] The heating modules are preferably chosen from among an infrared heater, an induction heater, a convector, a forced air heater, a water spray heater, a water-air spray heater and a portion of the width of a heated roller. Preferably, the heating modules are infrared heaters.

[032] Thanks to this design, temperature variations across the strip width can be corrected and minimized. Preferably, the temperature variation of the wet film across the strip width at the heating device outlet is less than 1 °C. This improves the homogeneity of the coating gloss across the strip width.

[033] According to another variant, the heating device (3) comprises sequentially along the path of the moving strip a base heater covering the entire width of the path (P) and the plurality of heating modules described above. The base heater can be an infrared heater or an inductor. Thanks to this design, part of the energy required to achieve the correct temperature of the wet film at the output of the heating device is supplied by the base heater. Each heating module of the plurality of heating modules independently supplies the remaining part of the energy and can adjust it accordingly. Petition 870250099327, dated 10 / 30 / 2025, page 22 / 120 14 / 47 required.

[034] The heating device (3) is preferably positioned above the path (P) so that the wet film applied to the top of the strip is heated directly. The heating device can also be positioned above and below the path (P) to minimize thermal gradients.

[035] The coil coating line (1) further comprises an ultraviolet (UV) curing device (4). The purpose of this equipment is to cure the surface of the wet film of UV-cured ink. It has been observed that this surface curing generates a very fine texture on the surface of the film which, combined with coupling agents and possible other fillers, contributes to the gloss of the organic coating after complete curing of the wet film by electron beam.

[036] According to one variant, the ultraviolet curing device (4) covers the entire path width (P) of the moving strip. In this case, the wet film surface is cured uniformly along the width of the strip when exposed to UV.

[037] According to another variant, the ultraviolet curing device (4) comprises a plurality of UV modules distributed along the path width (P). In other words, the plurality of UV modules forms a row substantially parallel to the path width (P), i.e., perpendicular to the direction of movement of the strip. For clarity, the UV modules described here are independent of each other and positioned adjacent, but may be physically inseparable. They may be individually controllable parts of a single UV curing device.

[038] Thanks to this design, different portions of the path / strip width can be exposed to different doses of UV. This helps to correct and minimize brightness variations across the strip width. Consequently, the Petition 870250099327, dated 10 / 30 / 2025, page 23 / 120 15 / 47 The heating device preferably comprises a plurality of heating modules forming a row substantially parallel to the width of the path (P), each heating module being suitable for heating a portion of the width of the strip, which is then exposed to UV radiation from a UV module. In other words, each portion of the width covered by a given UV module corresponds to the portion of the width covered by a corresponding heating module.

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

[040] The ultraviolet curing device (4) is preferably mobile along the path (P) of the moving strip. It allows the length between the UV curing device and the EB curing device to be adjusted, i.e., extended or shortened. In fact, it has been observed that the surface wrinkles or roughness initiated during UV curing develop further during the time interval between UV curing and EB curing, which affects the gloss of the organic coating.

[041] In the case of a plurality of UV modules, each UV module is preferentially mobile along the path (P), independently of the others.

[042] The coil coating line (1) further comprises an electron beam curing device (5). The purpose of this equipment is to cure the wet film of the radiantly curing ink, i.e., its full thickness. It also freezes the surface roughness that appears on the surface of the wet film during UV curing and that develops further during the time interval between UV curing and EB curing. The EB device is generally operated under the following conditions: 100-200 kV, 20-50 kGy, inerting with nitrogen below 200 ppm O2. Petition 870250099327, dated 10 / 30 / 2025, p. 24 / 120 16 / 47

[043] Preferably, the coil coating line (1) further comprises a wet film temperature measuring device (6) positioned downstream of the heating device (3) and upstream of the ultraviolet curing device (4). This wet film temperature measuring device measures the wet film temperature before it enters the UV curing device. It can measure the wet film temperature along the entire width (P) of the moving strip or it can measure the temperature in only a part of the width. Examples of wet film temperature measuring devices are pyrometers, thermal cameras and thermocouples. The measured temperature can be expressed in °C, °F or K.

[044] In the case where the wet film temperature measuring device measures the temperature in only a part of the width, the measurement in that part can be considered relevant enough to manage the brightness of the entire width of the strip.

[045] Alternatively, a plurality of wet film temperature measuring devices is positioned downstream of the heating device (3) and upstream of the UV curing device, so that the entire path width (P) of the moving strip is covered. They form a row substantially parallel to the path width (P). Consequently, the heating device preferably comprises a plurality of heating modules forming a row substantially parallel to the path width (P), each heating module being suitable for heating a portion of the strip width, the temperature of which is then measured by a wet film temperature measuring device.

[046] To further increase the control of the wet film temperature in the UV curing device, the wet film temperature measuring device (6) and the ultraviolet curing device (4) should not be separated by more than 2 meters, preferably not more than 1 meter, or Petition 870250099327, dated 10 / 30 / 2025, page 25 / 120 17 / 47 The wet film temperature should not be measured for more than 4 seconds before curing the wet film in the UV curing device, preferably no more than 2 seconds. Alternatively or additionally, the portion of the path (P) of the moving strip between the wet film temperature measuring device and the UV curing device can be thermally insulated to maintain the wet film at the measured temperature before being cured in the UV curing device.

[047] The coil coating line (1) further comprises a gloss measuring device (7) positioned downstream of the electron beam curing device (5). This gloss measuring device measures the gloss of the organic coating after EB curing. It can measure the gloss of the organic coating along the entire path width (P) of the moving strip or it can measure the gloss in only a part of the width. Examples of gloss measuring devices are gloss meters. The measured gloss is preferably expressed in GU (Gloss Units). The 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 20°, 60° or 85°. More preferably, the gloss is measured with a geometry of 60°.

[048] In the case where the brightness measuring device measures brightness in only a part of the width, the measurement in that part can be considered relevant enough to manage the brightness of the entire width of the strip.

[049] Alternatively, a plurality of brightness measuring devices is positioned downstream of the EB curing device so that the entire path width (P) of the moving strip is covered. They form a row substantially parallel to the path width (P). Consequently, the heating device preferably comprises a plurality of heating modules forming a row substantially parallel to the Petition 870250099327, dated 10 / 30 / 2025, page 26 / 120 18 / 47 path width (P), each heating module being suitable for heating a portion of the strip width, the brightness of which is then measured by a brightness measuring device. Consequently, the UV curing device preferably comprises a plurality of UV modules forming a row substantially parallel to the path width (P), each UV module being suitable for UV exposing a portion of the strip width, the brightness of which is then measured by a brightness measuring device.

[050] The coil coating line (1) is preferably equipped with a strip speed measuring device, most preferably positioned at the level of a guide roller. An example of a strip speed measuring device is a tachometer integrated into the roller shaft.

[051] The coil coating line (1) may further comprise an inductor (8) upstream of the paint applicator (2). It may heat the strip before it reaches the paint applicator. Having a heated strip in the paint applicator favors paint application. Furthermore, the temperature reached by the strip in the inductor may be adjusted to correct possible gloss deviations, as will be described in detail later.

[052] The coil coating line (1) may further comprise an entry section with an unwinder (9) for unwinding the strip to be coated onto the line. The unwinder may be combined with a welding machine or a sewing machine, so that the front end of the strip to be coated can be fixed to the rear end of the previous strip.

[053] Alternatively, the coil coating line can be coupled to a galvanizing line, so that the strip coated with the metal alloys contained in the galvanizing line bath is directly coated with the organic coating, without the need for first Petition 870250099327, dated 10 / 30 / 2025, p. 27 / 120 19 / 47 roll it up and then unroll it.

[054] The coil coating line (1) may further comprise an input accumulator (10) located in the line's input section, downstream of the uncoiler, if applicable. The accumulator is equipment that accumulates a certain amount of strip. This is a set of upper and lower banks of rollers, through which the metal strip is passed in a serpentine shape, and stores pieces of metal as the two banks of rollers move apart. The total length of metal stored depends on the line's design speed, generally 60 seconds of steady-state metal processing time. When the input section of the coil coating line stops, the roller banks move towards each other, and the metal stored in the accumulator continues to feed the remainder of the coil coating line.

[055] The coil coating line (1) may further comprise a cleaning section (11), positioned downstream of the inlet section, in particular downstream of the inlet accumulator, if applicable. In this section, the strip is subjected to a surface preparation step. This type of preparation comprises at least one step selected from rinsing, degreasing and a conversion treatment. The aim of rinsing is to remove loose dirt particles, potential residues of conversion solutions, soaps that may have formed and to obtain a clean and reactive surface. The aim of degreasing is to clean the surface, removing all traces of organic dirt, metallic particles and dust from the surface. Preferably, degreasing is carried out in an alkaline environment. The conversion treatment includes the application to the strip of a conversion solution that reacts chemically with the surface and thus enables the formation of a conversion layer.This last step increases paint adhesion and corrosion resistance. Conversion treatment is preferred. Petition 870250099327, dated 10 / 30 / 2025, p. 28 / 120 20 / 47 an acidic solution that does not contain chromium. More preferably, the conversion treatment is based on hexafluorotitanic acid or hexafluorozirconic acid.

[056] The coil coating line (1) may further comprise a primer section, upstream of the paint applicator (2) and downstream of the cleaning section, if applicable. 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 paint applicator and a curing apparatus. Depending on the nature of the primer, the curing apparatus 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 EB curing device.

[057] The coil coating line (1) may further comprise an output accumulator (12) located in the line's output section, downstream of the EB curing device. The output accumulator is similar to the input accumulator described above.

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

[059] The invention also relates to a gloss management tool for managing the gloss of an organic coating formed by applying and curing a wet film of energy-cured ink on a moving strip in a coil coating line (1), comprising, sequentially along the path (P) of the moving strip (S), an ink applicator (2), a heating device (3), comprising a heating module, an ultraviolet curing device (4) and an electron beam curing device (5).

[060] The brightness management tool comprises a Petition 870250099327, dated 10 / 30 / 2025, page 29 / 120 21 / 47 adjustment module to define a gloss value (Gs) for the organic coating and a gloss range (Rs) for the organic coating.

[061] The gloss management tool further comprises an acquisition module configured to collect the gloss (G) measurement of the organic coating in at least a portion of the width downstream of the electron beam curing device. Preferably, the acquisition module is further configured to collect the temperature (T) measurement of the wet film in at least a portion of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device.

[062] The brightness management tool further comprises a correction module configured to correct a deviation of the measured brightness (G) beyond the defined brightness range (Rs), the correction comprising a sub-step of calculating the correction (CP) to be applied to the power of the heating module, taking into account (Gs) and the measured brightness (G), with a closed-loop controller and a sub-step of adjusting a coil coating line configuration, taking into account the calculated correction (CP).

[063] The brightness management tool may include a processing unit consisting, for example, of a memory and a processor coupled to the memory. The electronic monitoring device may also include a display screen and input / output means, such as a keyboard and a mouse, each connected to the processing unit. Each configuration module, acquisition module and correction module may be implemented as executable software by the processor.

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

[065] From a process point of view, brightness management of Petition 870250099327, dated 10 / 30 / 2025, page 30 / 120 22 / 47 An organic coating formed by applying and curing a wet film of radiant-curing ink on a moving strip in the coil coating line described above is primarily based on the discovery that the temperature of the wet film before UV curing is critical. In particular, the inventors observed that, in double curing for coil coating, there can be a relationship between the temperature of the wet film before UV curing and the gloss of the organic coating after EB curing. Consequently, any deviation in gloss after EB curing can be efficiently and reproducibly corrected by adjusting the power of the heating module and, therefore, the temperature of the wet film before UV curing.

[066] The method is applied to a moving strip. The strip may be a single coil unwound at the entrance of the coil coating line. More generally, the strip is composed of different coils connected to each other end to end. The coils form an essentially continuous strip, whose characteristics and technical specifications to be achieved at the exit of the coil coating line vary over time. The strip is moved along the path (P) of the coil coating line so that the wet film of energy-cured ink is applied, preferably heated, and double-cured. In particular, the strip is moved along the path (P) of the coil coating line so that the wet film of energy-cured ink is first applied to the strip by the ink applicator, then heated by the heating module, then exposed to UV light in the ultraviolet curing device, and finally cured in the electron beam device.Optionally, the strip can be preheated with an inductor (8) positioned upstream of the ink applicator (2). Optionally, the energy-cured ink can be heated in the ink applicator.

[067] A first embodiment of the method is described with reference to Figure 2. Petition 870250099327, dated 10 / 30 / 2025, p. 31 / 120 23 / 47

[068] The first step (100) of the method for brightness management is the definition of some values ​​necessary for correct regulation.

[069] The defined gloss value (Gs) of the organic coating is initially defined. This value corresponds to the gloss requested by the customer or the coil coating line operator. From a practical point of view, it can be entered manually in the gloss management tool, in particular in the configuration module. Alternatively, it can be obtained automatically from the coil coating line order book, in particular in the scheduling tool.

[070] Since small deviations in gloss along the length of the strip are generally acceptable from a quality standpoint, a defined gloss range (Rs) of the organic coating gloss is also defined. It can be entered as a range, with a minimum and a maximum gloss, or it can be entered as a standard deviation of the defined gloss value (Gs). Naturally, if, for some reason, it is necessary to avoid small deviations, the defined gloss value (Gs) can be entered as minimum and maximum gloss, or the standard deviation can be set to zero. From a practical standpoint, the defined gloss range (Rs) can be entered manually in the gloss management tool, in particular in the configuration module. Alternatively, it can be obtained automatically in the coil coating line management tool or in the coil coating line order book, in particular in the scheduling tool.The defined gloss range (Rs) of the gloss can also be obtained from standards such as EN10169:2013.

[071] In a second step (120) of the gloss management method, the gloss (G) measurement of the organic coating in at least a portion of the downstream width of the electron beam curing device is collected. Petition 870250099327, dated 10 / 30 / 2025, page 32 / 120 24 / 47

[072] Preferably, the temperature (T) of the wet film is also measured in at least a portion of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device. More preferably, the temperature is measured with a wet film temperature measuring device as described above, and the gloss is measured with a gloss measuring device as described above.

[073] Preferably, measurements are taken at time intervals short enough for adequate brightness management. Examples of time intervals are: less than 30 s, less than 20 s, less than 10 s, less than 5 s, less than 2 seconds. More preferably, the measurement is substantially continuous or continuous. Preferably, measurements are collected at time intervals short enough for adequate brightness management. Examples of time intervals are less than every 10 s, less than every 5 s, less than every 2 s, less than every second. More preferably, the measurement is collected substantially continuously or continuous. Preferably, measurements are collected in the brightness management tool, in particular in the acquisition module, more preferably automatically with the appropriate interface.

[074] By width portion, it is understood that the moving strip is conceptually divided into adjacent portions across the width of the strip. There may be a single width portion or several. Consequently, the wet film and the organic coating may also be conceptually divided into the same width portions. By at least one width portion, it is understood that the method is implemented on one width portion, on several width portions, or across the entire width of the moving strip. If it is not implemented across the entire width, it is possible to measure and collect: - the gloss (G) of the organic coating in a single portion of Petition 870250099327, dated 10 / 30 / 2025, page 33 / 120 25 / 47 width, if the measurement at that width portion is considered relevant enough to manage the brightness across the entire width of the strip, or, - the sheens of the organic coating in a plurality of width portions, so that the sheen in each width portion can be managed independently of the other portions. [ 075] Similarly, it is optionally possible to measure and collect: - the temperature (T) of the wet film in a single width portion, if the measurement in that width portion is considered sufficiently representative of the average temperature across the entire width of the strip, or, - the temperatures of the wet film in a plurality of width portions, so that the temperature in each width portion can be adjusted independently of the other portions.

[076] In one variant, the collection step is performed after the adjustment step.

[077] In another variant, particularly during continuous operation of the coil coating line, the collection step can be performed in parallel with the adjustment step. In the case of continuous operation, as the strip is composed of different coils connected to each other end-to-end, changes in the strip characteristics and technical specifications frequently occur. While the collection step is in progress, any of the defined parameters, in particular any of the defined gloss values ​​(Gs) and / or the defined gloss range (Rs), may need to be modified for some reason, such as a change in the specified gloss or a change in the energy-cured ink. Consequently, the configuration step is performed.

[078] Preferably, in this second stage (120) of the brightness management method, the PW power of the heating module is also collected. Petition 870250099327, dated 10 / 30 / 2025, page 34 / 120 26 / 47

[079] In a third step (130) of the brightness management method, a possible deviation of the measured brightness (G) beyond the defined brightness range (Rs) is corrected. First, a possible brightness deviation is evaluated by comparing the measured brightness (G) with the defined brightness value (Gs) and / or with the defined brightness range (Rs). If the measured brightness (G) is still within the defined brightness range (Rs), the settings are maintained. If the measured brightness (G) has deviated beyond the defined brightness range (Rs), the correction (CP) to be applied to the heating module power is calculated, taking into account (Gs) and the measured brightness (G), with a closed-loop controller.

[080] The brightness deviation assessment can be performed at any time. Preferably, at time intervals short enough to allow for proper brightness management. Examples of time intervals are: less than 30 s, less than 20 s, less than 10 s, less than 5 s, less than 2 and less than 2 seconds. More preferably, the assessment is substantially continuous or continuous.

[081] The calculation of the correction (CP) to be applied to the heating module power is performed with a closed-loop controller. Preferably, this controller is a proportional-integral-derivative controller. Since, in some cases, only one or two terms of the controller may provide adequate control, some controller parameters may be zeroed to disable some terms. In particular, at least one of the integral and derivative terms of the proportional-integral-derivative controller is active. By active, it is understood that the term is not zeroed / that it is used for the calculation. In other words, the proportional-integral-derivative controller is preferably a PI controller, a PD controller, an I controller, a D controller, or a PID controller.

[082] Consequently, he can calculate the correction (CP) according to a general formula equation: Petition 870250099327, dated 10 / 30 / 2025, page 35 / 120 27 / 47 Cp(t) = Kpe(t) + Kt&(τ)άτ + (7) Or CP(t) = Kp(e(t) +1- £ e(r)dr + Td^) (8) 1 j Utz where e is the error, i.e., the difference between a desired setpoint and a measured process variable, t is the time or instantaneous time, and τ is the integration variable. Other control functions are well known to experts in the field and can be used to control the gloss of the organic coating.

[083] In a first variant of the correction calculation (CP), the closed-loop control is based directly on the gloss of the organic coating. In other words, the measured process variable is the measured gloss and the desired setpoint is (Gs). In this case, the correction (CP) is a function of the difference between (Gs) and the measured gloss (G).

[084] In particular, the correction (CP) to be applied to the power of the heating module can be calculated according to equation 1: CP(t) = Kpei(t) + Kt £ ef(r)dr + ÃuU~L(1) where Kp is the proportional gain, Ki is the integral gain, Kd is the derivative gain and e1 is the difference between (Gs) and the measured brightness (G).

[085] In particular, Ki > 0 and / or Kd > 0.

[086] The rules of good practice for the initial selections of Kp, Ki and Kd and their adjustment are well known to experts in the field. Kp, Ki and Kd can therefore be easily selected and adjusted as needed. The initial gains Kp, Ki and Kd can be entered manually in the brightness management tool, in particular in the configuration module. They can be set during the configuration step.

[087] Alternatively, the correction (CP) to be applied to the heating module power can be calculated according to the following equation: Petition 870250099327, dated 10 / 30 / 2025, page 36 / 120 28 / 47 Cp(t) = K„(e 1 (t) +1 jje, WA + Tu^2) (9) 1 j Utz where Kp is the proportional gain, Ti is the integration time, Td is the derivation time and e1 is the difference between (Gs) and the measured brightness (G).

[088] In particular, 1 / Ti > 0 and / or Td > 0.

[089] The rules of good practice for the initial selections of Kp, Ti and Td and their adjustment are well known to experts in the field. Kp, Ti and Td can therefore be easily selected and adjusted as needed. The initial terms Kp, Ti and Td can be entered manually into the brightness management tool, in particular in the configuration module. They can be set during the configuration step.

[090] In a second variant, where the collection step also includes collecting the temperature (T) measurement of the wet film in at least a portion of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device, as it has been observed that there is a relationship between the temperature of the wet film before UV curing and the gloss of the organic coating after EB curing, the closed-loop control of the heating module power is based on the temperature of the wet film in at least a portion of the width downstream of the heating module and upstream of the UV curing device. In other words, the measured process variable is the measured temperature and the desired setpoint is the corrected temperature (Tc) to be reached by the wet film, in at least a portion of the width downstream of the heating module and upstream of the UV curing device, to obtain the defined gloss value (Gs).

[091] Thus, in a first sub-step of the correction step, the corrected temperature (Tc) to be reached by the wet film is calculated in at least a portion of the width downstream of the heating module and upstream of the UV curing device.

[092] In general, the corrected temperature (Tc) is calculated from Petition 870250099327, dated 10 / 30 / 2025, page 37 / 120 29 / 47 according to equation 2: Tc = fl (T, G, Gs) (2) where the function (f1) is a predefined mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing. By predefined, it is understood that a calibration step, preferably as described below, was performed before implementing the method on the coil coating line.

[093] The function (f1) can be obtained in a calibration step performed before the configuration step. During this calibration step, wet films of the double-cure ink to be used in the coil coating line are heated to different temperatures, double-cured under standard curing conditions, and the gloss of the organic coatings is measured. The function (f1) can therefore be deduced. This calibration step can be performed once and for all and does not need to be performed every time the method according to the invention is implemented. The function (f1) can be manually entered into the gloss management tool, in particular in the configuration module.Alternatively, it can be obtained automatically by cross-referencing the predefined mathematical relationships entered in the gloss management tool, possibly in the form of a table, with the ink reference from the coil coating line order book, in particular from the scheduling tool. The function (f1) can be defined during the setup step.

[094] In particular, it has been observed that, for some commercially available energy-cured paints for coating steel coils, there is a linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing, as expressed by the following equation: Petition 870250099327, dated 10 / 30 / 2025, page 38 / 120 30 / 47 T = T0 - KG (10) where K is the constant of proportionality.

[095] In this case, the corrected temperature (Tc) is calculated according to equation 3: Tc = T + K (G - Gs) (3).

[096] The proportionality constant (K) can be obtained in a calibration step performed before the setup step. During this calibration step, wet films of the energy-cured ink to be used in the coil coating line are heated to different temperatures, double-cured under standard curing conditions, and the gloss of the organic coatings is measured. The proportionality constant (K) can therefore be deduced. 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 does not need to be performed every time the method according to the invention is implemented.

[097] From a practical standpoint, during the correction stage, the proportionality constant (K) is obtained from a predefined linear mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing, with the predefined linear mathematical relationship available to the coil coating line operator. By predefined, it is understood that a calibration step, preferably as described above, was performed before the method was implemented on the coil coating line. The proportionality constant (K) can be manually entered into the gloss management tool, in particular in the configuration module. Alternatively, it can be obtained automatically by cross-referencing the predefined linear mathematical relationships entered into the gloss management tool, possibly in the form of a table, with the ink reference from the book. Petition 870250099327, dated 10 / 30 / 2025, p. 39 / 120 31 / 47 of orders for the coil coating line, in particular for the programming tool.

[098] For example, it has been observed that, for some commercially available energy-cured paints for coating steel coils, K is generally between 0.3 and 1.2. More generally, K > 0.

[099] Once the corrected temperature (Tc) has been calculated, the correction (CP) to be applied to the power of the heating module is calculated as a function of the difference between (Tc) and the measured temperature (T).

[0100] In particular, in the case of a proportional integral derivative controller in parallel form, the correction (CP) can be calculated according to equation 4: CP(t) = K'pe2(t) + K'tJ0 β2(τ)άτ + K'dd-2~L- (4) where K'p is the proportional gain, K'i is the integral gain, K'd is the derivative gain and e2 is the difference between (Tc) and the measured temperature (T).

[0101] In particular, K'i > 0 and / or K'd > 0.

[0102] The rules of good practice for the initial selections of K'p, K'i and K'd and their adjustment are well known to experts in the field. K'p, K'i and K'd can therefore be easily selected and adjusted as needed. The initial gains K'p, K'i and K'd can be entered manually in the brightness management tool, in particular in the configuration module. They can be set during the configuration step.

[0103] Alternatively, in the case of a proportional-integral-derivative controller in standard form, the correction (CP) to be applied to the heating module power can be calculated according to the following equation: CP(t) = K1p(e2(t) + 1 J e2(T)dT + T'd) (11) where K'p is the proportional gain, T'i is the integration time, T'd is the derivation time and e2 is the difference between (Tc) and the measured temperature (T). Petition 870250099327, dated 10 / 30 / 2025, page 40 / 120 32 / 47

[0104] In particular, 1 / T'i > 0 and / or T'd > 0.

[0105] The best practice rules for the initial selections of K'p, T'i and T'd and their adjustment are well known to experts in the field. K'p, T'i and T'd can therefore be easily selected and adjusted as needed. The initial terms K'p, T'i and T'd can be entered manually into the brightness management tool, in particular in the configuration module. They can be set during the configuration step.

[0106] This second variant of the correction calculation (CP) is very convenient for avoiding the juxtaposition of interdependent closed-loop controls and for controlling that the wet film temperature does not exceed a maximum temperature Tmax that would degrade the energy-cured ink, as will be described in detail later.

[0107] Once the correction (CP) to be applied to the heating module power has been calculated, a line configuration is adjusted taking into account the correction (CP), so that the measured brightness deviation is corrected.

[0108] In particular, once the correction (CP) has been calculated, the power of the heating module is adjusted by the correction (CP). Adjusting the power of the heating module includes switching it on or off. Thanks to the adjustment of the heating module, the temperature of the wet film in the width portion downstream of the heating module and upstream of the ultraviolet curing device is corrected, and a gloss value (Gs) is obtained in the organic coating in the width portion downstream of the electron beam curing device. The adjustment of the heating module power can be done manually by an operator or automatically with the aid of the gloss management tool, in particular the correction module.

[0109] Alternatively, in the case where the coil coating line is equipped with an inductor upstream of the applicator of Petition 870250099327, dated 10 / 30 / 2025, p. 41 / 120 33 / 47 paint, once the correction (CP) has been calculated, the inductor power is adjusted so that the strip temperature at the paint applicator level is adjusted so that the gloss value (Gs) is obtained in the organic coating in at least a portion of the width of the moving stream downstream of the electron beam curing device. If the corrected temperature (Tc) has been calculated before the correction (CP) calculation, the inductor power is adjusted so that the wet film reaches the corrected temperature (Tc) in at least a portion of the width of the moving strip downstream of the cooling module / heating module and upstream of the ultraviolet curing device. This alternative way of correcting gloss is particularly useful in the case where the heating module is already at maximum capacity and the wet film temperature upstream of the ultraviolet curing device needs to be increased further.By further heating the strip on the inductor, the overheating provided by the heating module is reduced.

[0110] In one variant, the correction step (130) is performed after the collection step (120).

[0111] In another variant, particularly during continuous operation of the coil coating line, the correction step can be performed in parallel with the collection step. In this case of continuous operation, as the strip is composed of different coils connected to each other end-to-end, changes in the strip's characteristics and technical specifications frequently occur. These changes can cause deviations in gloss. While the collection step is in progress, the correction step is performed to correct the measured gloss.

[0112] Optionally, the method also includes a step (110) during which the initial line conditions are defined. This step is called the initial line adjustment step. As explained above, the method is such that any deviation of the measured brightness beyond the brightness range Petition 870250099327, dated 10 / 30 / 2025, page 42 / 120 The defined gloss value (Rs) is corrected. That said, at the start of a production campaign on the roll coating line or after a significant change, for example, in strip format, ink thickness, ink color, or line speed, line conditions may change from the conditions suitable for achieving the defined gloss value (Gs). In this case, the heating module may not heat up adequately and / or may need some time to reach the power corresponding to the CT correction and / or may not be powerful enough to allow the wet film to reach the corrected temperature (Tc). Consequently, a portion of the coated strip may have to be discarded because the gloss is out of specification. Furthermore, the UV dose to which the wet film must be exposed to initiate the surface roughness that will result in the defined gloss value may not be adequate.In this case, the heating module needs to compensate for the altered UV dose, possibly through intense heating, which takes time. Again, a portion of the coated strip may have to be discarded because the brightness is out of specification. To minimize the length of the coated strip that is out of specification, it is advantageous to define the initial conditions of the line.

[0113] To this end, in a first sub-step, several process parameters and / or specifications of the coated strip are collected. An example of a process parameter is the initial line speed LS0. Preferably, this is the 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 ink applicator. The initial film thickness is preferably that which 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 before the ink applicator, preferably before the inductor. Examples of specifications are the initial strip thickness STh0, the initial strip width SWd0, and the color of the Petition 870250099327, dated 10 / 30 / 2025, page 43 / 120 35 / 47 ink. Preferably, the initial line speed LS0, initial thickness FTh0, initial strip thickness STh0, initial strip width SWd0, and ink color are collected. From a practical point of view, the process parameters and / or specifications can be manually entered into the gloss management tool, in particular in the configuration module. Alternatively, they can be automatically obtained from the order book of the coil coating line, in particular from the programming tool, and / or deduced from the order book. For example, the initial film thickness FTh0 can be deduced from the organic coating thickness specified in the order book.

[0114] Once the process parameters and / or specifications have been collected, in a second sub-step, the initial line conditions are defined taking into account the collected process parameters and / or specifications. In particular, they are calculated from the collected process parameters and / or specifications. The following initial line conditions can be defined: - the initial power PW0 of the heating module, - the initial UV dose D0 of the ultraviolet curing device or UV module, if applicable, - the initial length L0 between the ultraviolet curing device, or the UV module if applicable, and the electron beam curing device.

[0115] The initial power PW0 can be defined by knowing the mass flow rate of the moving strip, the specific heat of the strip, and the heating efficiency. The initial UV dose D0 can be defined based on data obtained in a calibration step performed before the initial line setup step. The initial length L0 can be defined based on data obtained in a calibration step performed before the setup step. Petition 870250099327, dated 10 / 30 / 2025, page 44 / 120 36 / 47 initial of the line.

[0116] From a practical standpoint, the initial line conditions can be manually entered into the coil coating line management tool. Alternatively, they can be automatically injected by the gloss management tool into the coil coating line management tool.

[0117] In one variant, the initial line setting step (110) is performed before the setting step (100). This helps to start production with line conditions already optimized for the first coil of the production campaign, as well as an initial combination of the defined gloss value (Gs) and the defined gloss range (Rs). During production, the collection step and the correction step can be performed to manage gloss. When any of the defined parameters, in particular any of the defined gloss values ​​(Gs) and / or the defined gloss range (Rs), needs to be modified for some reason, such as a change in the specified gloss or a change in the energy-cured ink, the performance of the collection step (120) and the correction step (130) is relied upon to keep the measured gloss within the defined gloss range (Rs).

[0118] In another variant, the initial line definition step (110) is performed after the definition step (100), as illustrated in Figure 2. In this way, the configuration of the initial line conditions can be done taking into account the defined brightness value (Gs). The line conditions are therefore better optimized for the first reel of the production campaign. Furthermore, during production, when any of the defined parameters, in particular any of the defined brightness values ​​(Gs) and / or the defined brightness range (Rs), needs to be modified for any reason, the initial line settings can be reset to help minimize the transition period. Petition 870250099327, dated 10 / 30 / 2025, page 45 / 120 37 / 47

[0119] In another variant, the initial line definition step (110) is performed before and after the definition step (100) to take advantage of both variants described above.

[0120] In another variant, particularly during continuous coil coating line operation, the initial line setup step can be performed in parallel with the take-up step. In this continuous operation case, since the strip is composed of different coils connected end-to-end, changes in the strip characteristics and technical specifications frequently occur. Resetting the line conditions when one of these changes occurs helps to achieve the defined gloss value as quickly as possible.

[0121] A second embodiment of the method is now described with reference to Figure 3.

[0122] This implementation differs primarily from the first, as the correction stage includes additional sub-stages for: - ensure that the temperature of the wet film upstream of the UV curing device does not exceed a maximum temperature Tmax that would degrade the UV curing ink and, - correct the deviation of the measured brightness (G) accordingly.

[0123] Thanks to this configuration, the method further prevents thermal degradation of the wet film when heated in the heating module.

[0124] The details provided in the description of the first embodiment apply to the second embodiment. The additional steps and corresponding resources are described in detail below.

[0125] The definition step (100) also includes setting a maximum temperature Tmax for the energy-cured ink. This temperature may be the one recommended by the ink supplier. In this way Petition 870250099327, dated 10 / 30 / 2025, page 46 / 120 38 / 47 Alternatively, it can be identified by the coil coating line operator, notably by measuring the ink monomer emissions as a function of temperature, this measurement being performed offline or possibly online in the heating module. From a practical point of view, the maximum temperature Tmax can be manually entered into the gloss management tool, in particular in the configuration module. Alternatively, it can be obtained automatically by cross-referencing the different maximum temperatures entered into the gloss management tool with the ink reference from the coil coating line order book, in particular in the programming tool.

[0126] The collection step (120) comprises collecting the temperature (T) measurement of the wet film in at least one portion of the width of the moving strip downstream of the heating module and upstream of the ultraviolet curing device.

[0127] The collection stage (120) further comprises the collection of the UV dose (D) from the UV module. The power of the UV module is generally known to the operator, possibly by the roll coating line management tool, but, for a given power, the actual UV dose to which the wet film is exposed varies with the LS line speed. Consequently, the UV dose is calculated based on the power of the UV module and the line speed and collected. The line speed itself is generally known to the operator, possibly by the roll coating line management tool.

[0128] Preferably, the UV dose is recalculated and collected each time the UV module power and / or line speed are adjusted. More preferably, the UV dose collection is substantially continuous. Preferably, the UV dose is collected in the brightness management tool, in particular in the acquisition module, more preferably Petition 870250099327, dated 10 / 30 / 2025, page 47 / 120 39 / 47 automatically with the appropriate interface.

[0129] During the correction step (130), if the corrected temperature (Tc) has been calculated before the correction calculation (CP), it is compared with the maximum temperature Tmax. Otherwise, the correction step may include a sub-step of calculating the corrected temperature (Tc) to be reached by the wet film, in at least a portion of the width downstream of the heating module and upstream of the ultraviolet curing device. This sub-step may be performed after the correction calculation (CP) or at any other appropriate time. Once this sub-step is completed, Tc may be compared to the maximum temperature Tmax. Alternatively, T may be compared to the maximum temperature Tmax.

[0130] If Tc (or T) is less than Tmax, the power of the heating module is adjusted by the correction (CP), as detailed in the first embodiment.

[0131] If Tc (or T) is greater than Tmax, the gloss must be corrected without further increasing the power of the heating module. One way to do this is to adjust, in particular by increasing, the power of the UV module. In fact, it has been observed that this affects the gloss of the organic coating. The more the UV dose on the wet film increases, the more the gloss decreases. Consequently, the correction step (130) further comprises the calculation of the correction (CD) to be applied to the UV dose to which the wet film, in at least a portion of the width of the moving strip, must be exposed in the UV module, according to equation 5: CD = f2(G, Gs) (5).

[0132] Equation (5) can be obtained in a calibration step performed before the correction step, preferably before the setting step. During this calibration step, the wet films of the energy-cured ink to be used in the roll coating line are exposed to Petition 870250099327, dated 10 / 30 / 2025, page 48 / 120 40 / 47 different UV doses, cured by EB under standard curing conditions, and the gloss of the organic coating is measured. The function (f2) can therefore be deduced for each energy-cured ink. This calibration step can be performed once and does not need to be performed every time the method according to the invention is implemented. Alternatively, the function (f2) can be a PID function of the difference between (Gs) and the measured gloss (G).

[0133] Preferably, the function (f2) of the predefined mathematical relationship between the UV dose to which the wet film of the energy-cured ink is exposed and the gloss of the organic coating after electron beam curing is defined during the configuration step. By predefined, it is understood that a calibration step, preferably as described above, has been performed before the implementation of the method on the coil coating line. The function (f2) can be entered manually in the gloss management tool, in particular in the configuration module. Alternatively, it can be obtained automatically by cross-referencing the predefined mathematical relationships entered in the gloss management tool with the ink reference from the coil coating line order book, in particular in the programming tool.

[0134] For example, it has been observed that, for commercially available UV curing inks for coating steel coils, f2 is generally related to a gloss curve that decreases towards an asymptote as the UV dose increases.

[0135] Once the correction (CD) to be applied to the UV dose has been calculated, a line configuration different from the power of the heating module and, if applicable, the power of the inductor, is adjusted taking into account the calculated correction (CD), so that the deviation of the measured brightness is corrected.

[0136] In the variant illustrated in Figure 3, once the correction (CD) to be applied to the UV dose has been calculated, the power of the UV module is Petition 870250099327, dated 10 / 30 / 2025, p. 49 / 120 41 / 47 adjusted, in particular increased, so that the wet film in at least a portion of the width of the moving strip is exposed to the UV dose Dc = D + CD in the UV module. Thanks to the adjustment of the UV module, the UV dose to which the wet film is exposed in the portion of the width of the UV module is corrected and a brightness value (Gs) is obtained in the organic coating in the portion of the width downstream of the electron beam curing device. The adjustment of the UV module power can be done manually by an operator or automatically with the help of the brightness management tool.

[0137] A third embodiment of the method is described below with reference to Figure 4.

[0138] This implementation differs from the second mainly because the correction stage includes additional sub-stages for: - ensure that the UV dose does not exceed the maximum UV dose Dmax to which the wet film can be exposed, - Correct the deviation of the measured brightness (G) accordingly.

[0139] Thanks to this configuration, the method further prevents over-curing of the wet film in the UV curing device, which can impair gloss.

[0140] The details provided in the description of the first and second embodiments apply to the third embodiment. The additional steps and corresponding resources are described in detail below.

[0141] In this embodiment, the UV module of the coil coating line ultraviolet curing device is movable along the path (P). Consequently, the length (L) between the UV module and the electron beam curing device can be adjusted.

[0142] The definition step (100) also includes setting a maximum UV dose Dmax to which the wet film can be exposed in the UV module. This UV dose may be the one recommended by the ink supplier. Petition 870250099327, dated 10 / 30 / 2025, page 50 / 120 42 / 47 Alternatively, it can be identified by the coil coating line operator, mainly during a calibration step. From a practical point of view, the maximum UV dose Dmax can be manually entered into the gloss management tool, particularly in the configuration module. Alternatively, it can be obtained automatically by cross-referencing the different maximum UV doses entered into the gloss management tool with the ink reference from the coil coating line order book, particularly from the programming tool.

[0143] The collection step (120) further comprises collecting the length (L) between the UV module and the electron beam curing device. This length is generally known to the operator, possibly by the coil coating line management tool. It can be collected manually. Preferably, it is collected in the gloss management tool, more preferably automatically with the appropriate interface. Preferably, it is collected only when the length (L) is modified.

[0144] During the correction step (130), once the correction (CD) to be applied to the UV dose has been calculated, the sum D + CD (referred to below as Dc) is compared to the maximum UV dose Dmax. If Dc is less than Dmax, the power / adjustment of the UV module is adjusted so that the wet film in at least a portion of the width of the moving strip is exposed to the UV dose Dc in the UV module. Thanks to the adjustment of the UV module, the UV dose to which the wet film is exposed in the portion of the width of the UV module is corrected and a brightness value (Gs) is obtained in the organic coating in the portion of the width downstream of the electron beam curing device, as in the second embodiment.

[0145] If Dc is greater than Dmax, the brightness must be corrected without further increasing the UV dose of the UV module. One way to do this is Petition 870250099327, dated 10 / 30 / 2025, page 51 / 120 43 / 47 adjust, in particular to extend, the length between the UV module and the electron beam curing device. In fact, it has been observed that this affects the gloss of the organic coating. The longer the time between UV curing and EB curing, the lower the gloss. Consequently, the correction step (130) further comprises the calculation of the correction (CL) to be applied to the length (L) between the UV module and the electron beam curing device, according to equation 6: CL = f3 (G, Gs) (6).

[0146] Equation (6) can be obtained in a calibration step performed before the correction step, preferably before the curing step. During this calibration step, wet films of the UV curing ink to be used in the coil coating line are sequentially exposed to UV curing and EB curing under standard curing conditions, with varying time between the two cures, and the gloss of the organic coating is measured. The function (f3) can therefore be deduced for each energy-cured ink. This calibration step can be performed once and does not need to be performed every time the method according to the invention is implemented. Alternatively, the function (f3) can be a PID function of the difference between (Gs) and the measured gloss (G).

[0147] Preferably, the function (f3) of the predefined mathematical relationship between the length between the UV module and the electron beam curing device and the gloss of the organic coating after electron beam curing is defined during the configuration step. By predefined, it is understood that a calibration step, preferably as described above, has been performed before the implementation of the method on the coil coating line. The function (f3) can be entered manually in the gloss management tool, in particular in the configuration module. Alternatively, it can be obtained automatically by crossing the relationships Petition 870250099327, dated 10 / 30 / 2025, page 52 / 120 44 / 47 predefined mathematical functions entered into the gloss management tool with the ink reference from the coil coating line order book, specifically in the scheduling tool.

[0148] For example, it has been observed that, for commercially available radioactive curing paints for coating steel coils, f3 is generally related to a decreasing brightness curve towards an asymptote as L increases.

[0149] Once the correction (CL) to be applied to the length between the UV module and the electron beam curing device has been calculated, a line configuration different from the power of the heating module, and different from the power of the inductor, if applicable, and different from the power of the UV module, is adjusted taking into account the calculated correction (CL), so that the deviation of the measured brightness is corrected.

[0150] In the variant illustrated in Figure 4, once the correction (CL) is calculated, the length between the UV module and the electron beam curing device is adjusted, in particular extended, to the corrected length Lc = L + CL, so that the gloss value (Gs) is obtained on the organic coating in at least a portion of the width of the moving strip downstream of the electron beam curing device. The length adjustment can be done manually by an operator or automatically with the aid of the gloss management tool.

[0151] Alternatively, especially if the length between the UV module and the electron beam curing device cannot be extended or shortened, the line speed can be adjusted. In this case, the initial line configuration can be performed again to adjust the new line speed, the initial power PW0 of the heating module, the initial UV dose D0 of the ultraviolet curing device, and the initial length L0 between the ultraviolet curing device and the electron beam curing device. Petition 870250099327, dated 10 / 30 / 2025, page 53 / 120 45 / 47 electrons.

[0152] The invention also relates to a method for forming an organic coating on a moving strip in a coil coating line, comprising, sequentially along the path (P) of the moving strip, an ink applicator, a heating device comprising a heating module, an ultraviolet curing device and an electron beam curing device, the method comprising the steps of: - Apply a wet film of energy-cured ink to the moving strip using the ink applicator. - heating the wet, energy-cured ink film in the heating module, - Exposing the wet, energy-cured ink film to UV radiation in the ultraviolet curing device, - Curing of the reverse-curing wet film of ink in the electron beam device to form the organic coating, the gloss of the organic coating being managed by: - Defining a gloss value (Gs) for the organic coating and a gloss range (Rs) for the gloss of the organic coating. - Collection of gloss (G) measurements of the organic coating in at least one width portion downstream of the electron beam curing device. - Correction of a deviation from the measured brightness (G) beyond the brightness range (Rs), this correction step consisting of a sub-step of calculating the correction (CP) to be applied to the power of the heating module, taking into account (Gs) and the measured brightness (G), with a closed-loop controller, and a sub-step of adjusting the configuration of the coil coating line, taking into account the calculated correction (CP).

[0153] All details provided regarding the method of Petition 870250099327, dated 10 / 30 / 2025, page 54 / 120 46 / 47 gloss management and all details provided regarding the coil coating line apply to the organic coating formation method.

[0154] The invention also relates to a method for manufacturing a pre-painted metal, comprising a metal strip and an organic coating, in a coil coating line comprising, sequentially along the path (P) of the moving metal strip, a paint applicator, a heating device comprising a heating module, an ultraviolet curing device and an electron beam curing device, the method comprising the steps of: - Apply a wet film of energy-cured ink to the moving metal strip using the ink applicator. - heating the wet, energy-cured ink film in the heating module, - Exposing the wet, energy-cured ink film to UV radiation in the ultraviolet curing device, - Curing the wet film of energy-cured ink in the electron beam device to form the organic coating, the gloss of the organic coating being managed by: - Define a gloss value (Gs) for the organic coating and a gloss range (Rs) for the gloss of the organic coating. - collect the gloss (G) measurement of the organic coating on at least a width portion downstream of the electron beam curing device, - Correcting a deviation in measured brightness (G) beyond the defined brightness range (Rs), this correction step consisting of a sub-step for calculating the correction (CP) to be applied to the heating module power, taking into account (Gs) and the measured brightness (G), with a controller of Petition 870250099327, dated 10 / 30 / 2025, page 55 / 120 47 / 47 closed loop, and a sub-step of adjusting the coating line on the coil, taking into account the calculated correction (CP).

[0155] All details provided regarding the gloss management method and all details provided regarding the coil coating line apply to the prepainted metal manufacturing method. Petition 870250099327, dated 10 / 30 / 2025, page 56 / 120

Claims

1 / 5 Claims 1. METHOD FOR MANAGING THE GLOSS OF AN ORGANIC COATING formed by applying and curing a wet film of energy-cured ink on a moving strip (S) in a coil coating line (1), comprising, sequentially along the path (P) of the moving strip (S), an ink applicator (2), a heating device (3) comprising a heating module, an ultraviolet curing device (4) and an electron beam curing device (5), the method characterized by comprising the steps of: - defining (100) a defined gloss value (Gs) for the organic coating and a defined gloss range (Rs) for the gloss of the organic coating, - collecting (120) the gloss measurement (G) of the organic coating in at least a width portion downstream of the electron beam curing device (5), - correcting (130) a deviation of the measured gloss (G) beyond the defined gloss range (Rs),This correction step comprises a sub-step for calculating the correction (CP) to be applied to the heating module power, taking into account (Gs) and the measured brightness (G), with a closed-loop controller, and a sub-step for adjusting a coil coating line configuration (1), taking into account the calculated correction (CP).

2. METHOD, according to claim 1, characterized in that the closed-loop controller is a proportional-integral-derivative controller.

3. METHOD, according to any one of claims 1 to 2, characterized in that the correction (CP) is a function of the difference between (Gs) and the measured brightness (G).

4. METHOD, according to any of the claims Petition 870250099327, of 10 / 30 / 2025, p. 57 / 120 2 / 5 1 to 3, characterized by the correction (CP) to be applied to the power of the heating module being calculated according to equation 1: CP(t) = Kpei(t) + Kt J0 e 1 (τ)άτ + ^^- (1) where Kp is the proportional gain, Ki is the integral gain, Kd is the derivative gain and e1 is the difference between (Gs) and the measured brightness (G).

5. METHOD, according to any one of claims 1 to 2, characterized in that the collection step (120) further comprises collecting the temperature measurement (T) of the wet film in at least one portion of the width of the moving strip (S) downstream of the heating module and upstream of the ultraviolet curing device (4), and in that the correction step (130) further comprises a sub-step of calculating the corrected temperature (Tc) to be reached by the wet film, in at least one portion of the width downstream of the heating module and upstream of the ultraviolet curing device (4).

6. METHOD, according to claim 5, characterized in that the corrected temperature (Tc) is calculated according to equation 2: Tc = f1 (T, G, Gs) (2) wherein the function (f1) is a predefined mathematical relationship between the wet film temperature before ultraviolet curing and the gloss of the organic coating after electron beam curing.

7. METHOD, according to claim 5, characterized in that the corrected temperature (Tc) is calculated according to equation 3: Tc = T + K (G - Gs) (3).

8. METHOD, according to any one of claims 5 to 7, characterized in that the correction (CP) is a function of the difference between (Tc) and the measured temperature (T).

9. METHOD, according to any one of claims 5 to 7, characterized by the correction (CP) to be applied to the power of the heating module being calculated according to equation 4: Petition 870250099327, 10 / 30 / 2025, p. 58 / 120 3 / 5 CP(t) = Κ'ρβ2(t) + Κ'f £ β2(τ')άτ + Κ'd ~~2~ (4) where K'p is the proportional gain, K'i is the integral gain, K'd is the derivative gain and e2 is the difference between (Tc) and the measured temperature (T).

10. METHOD, according to any one of claims 1 to 9, characterized by the substep of adjusting a coil coating line configuration (1) comprising adjusting the heating module power by correction (CP).

11. METHOD, according to any one of claims 5 to 9, characterized by: - ​​the ultraviolet curing device (4) comprising a UV module, - the setting step (100) further comprising setting a maximum temperature (Tmax) for the energy-cured ink, - the collection step (120) further comprising collecting the UV dose (D) from the UV module, - the sub-step of setting a coil coating line configuration (1) comprising: • assessing whether Tc is greater than Tmax, • otherwise, adjusting the power of the heating module by correction (CP), • if Tc is greater than Tmax: - calculating the correction (CD) to be applied to the UV dose to which the wet film in at least a portion of the width must be exposed in the UV module, according to equation 5: CD = f2 (G, Gs) (5) - setting a coil coating line configuration (1) different from the power of the heating module, taking into account the calculated correction (CD).

12. METHOD, according to claim 11, characterized Petition 870250099327, of 10 / 30 / 2025, page 59 / 120 4 / 5 by the substep of adjusting a coil coating line configuration (1) different from the heating module power comprising adjusting the UV module power so that the wet film in at least a portion of the moving strip width (S) is exposed to the corrected UV dose Dc = D + CD.

13. METHOD, according to claim 11, characterized by: - ​​the UV module being mobile along the path (P), - the setting step (100) further comprising the adjustment of a maximum UV dose (Dmax) to which the wet film is exposed in the UV module, - the collection step (120) further comprising the collection of the length (L) between the UV module and the electron beam curing device (5), - the sub-step of adjusting a coil coating line configuration (1), different from the power of the heating module, comprising: - evaluating whether D + CD is greater than Dmax, - otherwise, adjusting the power of the UV module so that the wet film in at least a portion of the width of the mobile strip (S) is exposed with the corrected UV dose Dc = D + CD, - if D + CD is greater than Dmax: • calculating the correction (CL) to be applied to the length between the UV module and the electron beam curing device (5) according to equation 6: CL = f3 (G,Gs) (6) • adjust a coil coating line setting (1) in addition to the power of the heating module and UV module, taking into account the calculated correction (CL)., 14. METHOD, according to claim 13, characterized by the substep of adjusting a coil coating line configuration (1), different from the power of the heating module and the UV module, comprising Petition 870250099327, 10 / 30 / 2025, page 60 / 120 5 / 5 adjusting the length between the UV module and the electron beam curing device (5) to the corrected length Lc = L + CL, so that the gloss value (Gs) is obtained in the organic coating in at least a portion of the width of the moving strip (S) downstream of the electron beam curing device (5).

15. COIL COATING LINE (1), characterized by sequentially comprising an ink applicator (2), a heating device (3) comprising a heating module, an ultraviolet curing device (4) and an electron beam curing device (5), the coil coating line (1) further comprising a gloss management tool for managing the gloss of an organic coating formed by applying and curing a wet film of an energy-cured ink on a moving strip (S) in the coil coating line (1), the gloss management tool comprising: - a configuration module that defines a defined gloss value (Gs) of the organic coating and a defined gloss range (Rs) of the organic coating gloss, - an acquisition module that collects the gloss measurement (G) of the organic coating in at least a downstream width portion of the electron beam curing device (5),- a correction module that corrects a deviation of the measured brightness (G) beyond the defined brightness range (Rs), the correction comprising a sub-step of calculating the correction (CP) to be applied to the power of the heating module, taking into account (Gs) and the measured brightness (G), with a closed-loop controller and a sub-step of adjusting a coil coating line configuration (1) taking into account the calculated correction (CP). Petition 870250099327, dated 10 / 30 / 2025, p. 61 / 120,

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