Method for managing gloss of coating on web coating production line

Abstract

The invention relates to a method for managing the gloss of an organic coating formed on a moving strip on a coil coating production line comprising, in order: a coating applicator, a heating device comprising a heating module, an ultraviolet curing device and an electron beam curing device, the method comprises correcting the deviation of the measured glossiness G beyond a set glossiness range Rs, the correction comprising: a sub-step of calculating, using a closed-loop controller, a correction value CP of the power to be applied to the heating module in consideration of Gs and the measured glossiness G; and a sub-step of adjusting the setting of the coil coating production line in consideration of the calculated correction value CP.

Description

Technical Field

[0001] This invention relates to a method for managing the gloss of an organic coating applied to a moving strip on a coil coating production line. Specifically, the moving strip is a metal-coated steel strip. Background Technology

[0002] Coil coating is a continuous, automated process for coating metals before they are manufactured into a final product. Steel or aluminum substrates are fed from a rolling mill in coil form. The metal coil is positioned at the start of the coil coating line, and in a continuous process, the coil is unwound, pre-cleaned, pre-treated, pre-primed, and pre-sprayed before being rewound and packaged at the other end for transport.

[0003] The product obtained through this process is pre-coated metal, also known as coil-coated metal, pre-treated metal, or pre-coated metal. It is commonly used in construction applications and equipment.

[0004] Traditionally, coatings used for roll-to-roll coatings are solvent-based. However, there has recently been interest in radiation curing, which uses ultraviolet light (UV process) or electron beam (EB curing process) to cure materials. Corresponding coatings known to be radiation-curable are solvent-free, and the curing process is triggered by exposure to high-energy UV light, which may bind with a suitable photoinitiator, or by exposure to accelerated electrons. The photoinitiator absorbs UV light and generates free radicals. These free radicals react with the double bonds of the monomers, initiating a chain reaction and polymerization. For both UV curing and electron beam (EB) curing, no initiator is required. The high radiation energy generates sufficient active material (free radicals) to allow polymerization to proceed spontaneously.

[0005] One characteristic of radiation-cured coatings is the high gloss produced by the high surface tension of the coating. With solvent-based coatings, to reduce this gloss and meet the requirements of the pre-painting market (for the construction market, gloss is typically between 15 GU and 30 GU), coating suppliers add matting agents. However, radiation-cured coatings, being very viscous due to the absence of solvents, allow for the addition of only small amounts of matting agents, and these agents do not permit low gloss levels. Furthermore, because the curing process of radiation-cured coatings is much faster than that of solvent-based coatings (1 to 2 seconds vs. 12 to 25 seconds), the migration of matting agents to the coating surface to achieve the desired gloss level is also very limited.

[0006] A method to mitigate this problem is known from WO81 / 00683, which discloses a curing process in which the coating is first irradiated with curing radiation of wavelengths that respond to the coating but have essentially no distribution below about 300 nm (e.g., UV), and subsequently irradiated with curing radiation of wavelengths that respond to the coating, including a large amount of radiation with wavelengths below 300 nm (e.g., EB). This dual curing is called dual curing. Gloss control is achieved by adjusting online parameters, including spectral distribution, intensity or dose of the initial radiation, or the time interval between the initial irradiation step and the subsequent irradiation step.

[0007] However, it has been observed that these online parameters are insufficient to manage gloss in an effective and reproducible manner. Summary of the Invention

[0008] Therefore, the object of the present invention is to overcome the shortcomings of the prior art process by providing a method for managing the gloss of an organic coating in an effective and reproducible manner, the organic coating being formed by applying a wet film of a radiation-cured coating onto a moving strip on a coil coating production line and curing the wet film of the radiation-cured coating.

[0009] For this purpose, the first subject of the present invention is a method for managing the gloss of an organic coating formed by applying a wet film of radiation-curable coating onto a moving strip on a coil coating line and curing the wet film of radiation-curable coating, the coil coating line comprising, in sequence along a path P of the moving strip: a coating applicator, a heating device including a heating module, an ultraviolet curing device, and an electron beam curing device, the method comprising the following steps:

[0010] - Set the gloss value G for the organic coating. s And the setting of the gloss range R for organic coatings. s ,

[0011] -Measurements of the gloss G of the organic coating are collected downstream of the electron beam curing apparatus in at least one width portion.

[0012] - For measured glossiness G that exceeds the set glossiness range R s The deviation is corrected, and the correction steps include: using a closed-loop controller, considering G s The measured gloss level G is used to calculate the correction value C for the power to be applied to the heating module. P The sub-steps; and considering the already calculated correction value C. P This is a sub-step to adjust the settings of the roll coating production line.

[0013] The method according to the invention may also have the following optional features, considered individually or in combination:

[0014] - This closed-loop controller is a proportional-integral-derivative (PID) controller.

[0015] -Correction value C P It is G s A function of the difference between the measured gloss level G and the actual gloss level G.

[0016] - Calculate the correction value C for the power to be applied to the heating module according to Equation 1. P :

[0017]

[0018] Among them, K p It is the proportional gain, K i It is the integral gain, K d It is the differential gain, and e1 is G s The difference between the measured gloss level G and the measured gloss level G.

[0019] -The method also includes an initial production line setup step, wherein:

[0020] ○ Collect multiple process parameters and / or strip specifications.

[0021] ○ Considering the collected process parameters and / or strip specifications, set at least one of the following initial production line conditions: initial power PW0 of the heating module, initial UV dose D0 of the UV curing unit, and initial length L0 between the UV curing unit and the electron beam curing unit.

[0022] The collection step further includes collecting a measurement of the temperature T of the wet film in at least one width portion upstream of the moving strip in the UV curing apparatus.

[0023] The calibration step further includes calculating the calibrated temperature T that the wet film will reach in at least one width portion downstream of the heating module and upstream of the UV curing apparatus. c Sub-steps,

[0024] - Calculate the corrected temperature T according to Equation 2. c :

[0025] T c = f1 (T, G, G) s (2)

[0026] Here, function f1 is a predetermined mathematical relationship between the temperature of the wet film before UV curing and the gloss of the organic coating after electron beam curing.

[0027] - Calculate the corrected temperature T according to Equation 3.c :

[0028] T c = T + K (G - G) s (3)

[0029] -Correction value C P It is T c A function of the difference between the measured temperature T and the actual temperature T.

[0030] - Calculate the correction value C for the power to be applied to the heating module according to Equation 4. P :

[0031]

[0032] Among them, K' p It is the proportional gain, K' i It is the integral gain, K' d It is the differential gain, and e2 is T c The difference between the measured temperature T and the measured temperature T.

[0033] - The sub-step of adjusting the settings of the coil coating production line includes adjusting the calibration value C. P To adjust the power of the heating module:

[0034] - The ultraviolet curing device includes a UV module.

[0035] - The setup steps also include setting the maximum temperature T for radiation-cured coatings. max ,

[0036] - The collection step also includes collecting the UV dose D from the UV module.

[0037] - The sub-steps for adjusting the settings of the coil coating production line include:

[0038] ○Assessment T c Does it exceed T? max ,

[0039] ○If T c Not exceeding T max Then through the correction value C P To adjust the power of the heating module,

[0040] ○If T c More than T max ,but:

[0041] ■ Calculate the correction value C for the UV dose that the wet film must be exposed to in at least one width portion of the UV module, according to Equation 5. D :

[0042] CD =f2(G,G s (5)

[0043] ■ Considering the calculated correction value C D The settings of the roll coating production line, excluding the power of the heating module, are adjusted.

[0044] - The sub-step of adjusting the settings of the roll coating production line, excluding the power of the heating module, includes adjusting the power of the UV module such that the wet film is exposed to a corrected UV dose D in at least one width portion of the moving strip. c =D+C D ,

[0045] - The UV module can move along path P.

[0046] - The setup process also includes setting the maximum UV dose D that the wet film can be exposed to in the UV module. max ,

[0047] The collection step also includes collecting the length L between the UV module and the electron beam curing device.

[0048] - The sub-steps for adjusting the settings of the roll coating production line, excluding the power of the heating module, include:

[0049] ■Assess D+C D Does it exceed D? max ,

[0050] ■If D+C D Not exceeding D max Then, adjust the power of the UV module so that the wet film is exposed to a corrected UV dose D in at least one width portion of the moving strip. c =D+C D ,

[0051] ■If D+C D More than D max ,but:

[0052] ●Calculate the correction value C for the length to be applied between the UV module and the electron beam curing device according to Equation 6. L :

[0053] C L = f3 (G, G s (6)

[0054] ● Consider the calculated correction value C L The settings for the roll coating production line, excluding the power of the heating module and the UV module, are adjusted.

[0055] - The sub-step of adjusting the settings of the roll-to-roll coating production line, excluding the power of the heating module and the UV module, includes adjusting the length between the UV module and the electron beam curing unit to the calibrated length L. c =L+C L In order to obtain a gloss value G on the organic coating in at least one width portion of the moving strip downstream of the electron beam curing apparatus. s .

[0056] The second subject of the present invention includes a roll-to-roll coating production line, which sequentially comprises: a coating applicator, a heating device including a heating module, an ultraviolet curing device, and an electron beam curing device. The roll-to-roll coating production line also includes a gloss management tool for managing the gloss of an organic coating formed by applying a wet film of radiation-cured coating onto a moving strip on the roll-to-roll coating production line and curing the wet film of the radiation-cured coating. The gloss management tool includes:

[0057] - Setting module, which sets the set gloss value G of the organic coating. s And the setting of the gloss level of the organic coating, the gloss range R s ,

[0058] - A data acquisition module that collects measurements of the gloss G of the organic coating in at least one width portion downstream of the electron beam curing apparatus.

[0059] - Correction module, the correction module corrects for measured gloss G that exceeds the set gloss range R. s The deviation is corrected, and this correction includes: using a closed-loop controller, taking into account G. s The measured gloss level G is used to calculate the correction value C for the power to be applied to the heating module. P The sub-steps; and considering the already calculated correction value C. P This is a sub-step to adjust the settings of the roll coating production line.

[0060] Other features and advantages of the present invention will be described in more detail in the following description. Attached Figure Description

[0061] The invention will be better understood by referring to the following figures and reading the following description, which is provided for illustrative purposes only and is in no way intended to be restrictive:

[0062] - Figure 1 This is a schematic diagram of a coil coating production line.

[0063] - Figure 2 This is a flowchart of a first embodiment of the method according to the present invention.

[0064] - Figure 3 This is a flowchart of a second embodiment of the method according to the present invention.

[0065] - Figure 4 This is a flowchart of a third embodiment of the method according to the present invention. Detailed Implementation

[0066] It should be noted that spatial relative terms used in this application, such as “upstream,” “downstream,” “lower,” “upper,” “above,” “below,” “before,” “after,” etc., refer to the position and orientation of different components of the roll coating production line.

[0067] The method according to the invention is intended for use with strip materials, such as metal strip materials. Steel, i.e., carbon steel or stainless steel, aluminum, and copper are examples of metal strip materials. Specifically, the steel strip may be bare or coated with a metallic coating on one or both sides. Possible examples of metal-coated steel include: galvanized steel; steel coated with a zinc alloy containing 5 wt.% aluminum. Steel coated with a zinc alloy comprising 55 wt.% aluminum, approximately 1.5 wt.% silicon, the remainder consisting of zinc and unavoidable impurities due to processing. Steel coated with an aluminum alloy comprising 8 wt.% to 11 wt.% silicon and 2 wt.% to 4 wt.% iron, with the remainder consisting of aluminum and unavoidable impurities due to processing. Steel coated with aluminum Steel coated with a zinc alloy comprising 0.5% to 20% aluminum, 0.5% to 10% magnesium, and the remainder consisting of zinc and unavoidable impurities due to processing; steel coated with an alloy comprising aluminum, magnesium, silicon, possible additional elements, and the remainder consisting of zinc and unavoidable impurities due to processing.

[0068] The method according to the invention is also intended for use in radiation-cured coatings. The term "radiation-cured coating" refers to a radiation-curable composition that is "cured" or dried using short-wavelength ultraviolet (UV) light and / or high-energy electrons from an electron beam (EB) source. Radiation-cured coatings typically contain liquid monomers and oligomers, and pigments, fillers, additives, and photoinitiators can be dispersed within the liquid monomers and oligomers, generally without the need for solvents or water. Therefore, radiation-cured coatings are essentially solvent-free. Radiation-cured coatings for dual curing preferably contain acrylate or methacrylate monomers and a photoinitiator.

[0069] Reference Figure 1 According to the present invention, the roll coating production line 1 mainly includes, along the path P of the moving strip, a coating applicator 2, a heating device 3 including a heating module, an ultraviolet curing device 4, and an electron beam curing device 5.

[0070] Path P is the path that the strip S follows from its inlet to its outlet in the coil coating line. Path P has a width and a length. Multiple pieces of equipment are positioned along this path to perform operations on the strip.

[0071] The paint applicator 2 is a device for applying a wet film of paint to one or both sides of a strip, the wet film having a predetermined paint thickness. Specifically, the purpose of the paint applicator 2 is to apply a wet film of radiation-cured paint. In the context of this invention, the technology of the paint applicator is not limited.

[0072] According to a variation of the invention, the paint applicator 2 is a paint roller coating machine. It is an automated machine that applies paint to one or both sides of a strip using a rotating roller. The paint applicator 2 is designed such that the strip passes through the machine to apply a paint layer to one or both sides of the strip. Paint roller coating machines have various designs, depending on the configuration of the roll coating line, the type of paint to be used, and the type of strip to be coated. Those skilled in the art will know which design is best suited for each situation. Generally, a paint roller coating machine includes a paint tray, a steel or ceramic pick-up roller, and a rubber-covered coating roller. The purpose of the paint tray is to hold the paint, circulate the paint, and preferably heat the paint. The pick-up roller may be partially immersed in the paint and may rotate clockwise or counterclockwise to pick up the paint and transfer it to the coating roller. The coating roller transfers the paint to the strip.

[0073] According to another variation of the invention, the paint applicator 2 is a curtain coating machine. In this case, a paint curtain is applied to a horizontal strip that is typically transverse to the curtain. As the strip is supported on support rollers, the paint falls from a height under gravity from the curtain die or waterfall. This method enables high production line speeds and multi-layer coatings.

[0074] Other examples of coating applicators are blade coaters, dip coaters or meniscus coaters, trough coaters, lever coaters, and sliding coaters.

[0075] Coatings are typically applied across the entire width of the strip using a coating applicator. By default, the width of the wet coating film, and therefore the width of the organic coating, is the same as the width of the strip.

[0076] The paint applicator 2 is preferably equipped with at least one paint heating device suitable for heating the paint and maintaining it at a set temperature. Heating the paint facilitates its application. Heating the paint also further simplifies gloss management because it minimizes the energy demand at the horizontal level of the heating module and thus minimizes the inertia of the heating module. In the case of a roller coater, the paint heating device can be a disc heater, i.e., a heater positioned in or around the paint disc. The paint heating device can also be a temperature-controlled roller, particularly a temperature-controlled pickup roller, which can be combined with a disc heater. In the case of a curtain coater, the paint heating device can be a heater located upstream of the curtain die. The paint heating device can also be a temperature-controlled support roller, which can be combined with a heater.

[0077] The paint applicator 2 is preferably equipped with a temperature measuring device for measuring the paint temperature and / or wet film temperature at the horizontal position of the paint applicator. The temperature device may be, for example, a temperature sensor, a pyrometer, or a thermal imager.

[0078] The roll coating production line 1 also includes a heating device 3, which comprises a heating module positioned downstream of the coating applicator 2 and upstream of the ultraviolet (UV) curing unit 4 along the path P of the moving strip. The purpose of the heating device 3 is to heat the wet film of the radiation-cured coating. The heating device further improves temperature control of the wet film on its surface before curing in the UV curing unit. Because the temperature of the strip leaving the coating applicator decreases at a rate depending on many parameters (strip properties, strip width, strip thickness, production line speed, etc.), the temperature of the wet film entering the UV curing unit can change significantly from time to time, which will adversely affect gloss. With the aid of the heating device, the temperature of the wet film can be adjusted very quickly.

[0079] The heating device is preferably selected from the following: infrared heater, induction heater, convection heater, forced air heater, water spray heater, water-air spray heater, and heating roller. Preferably, the heating device is an infrared heater. In the case of a water-based heater, since the wet film of the radiation-cured coating is applied to the top side of the strip, the water preferably only contacts the back side of the strip.

[0080] According to one variation, the heating device is made of a heating module that covers the entire width of the path P of the moving strip. In this case, the wet film is uniformly heated along the width of the wet film as it passes through the heating device.

[0081] According to another variation, the heating device 3 includes a plurality of heating modules distributed along the width of the path P. In other words, the plurality of heating modules form a row substantially parallel to the width of the path P, i.e., perpendicular to the direction of movement of the strip. For clarity, the heating modules described herein are positioned independently and adjacent to each other, but these heating modules may be physically inseparable from each other. These heating modules may be individually controllable parts of a single heating device.

[0082] The heating module is preferably selected from the following: an infrared heater, an induction heater, a convection heater, a forced air heater, a water spray heater, a water-air spray heater, and the width portion of a heating roller. Preferably, the heating module is an infrared heater.

[0083] Due to this design, temperature variations across the strip width can be corrected and minimized. Preferably, the temperature variation of the wet film at the outlet of the heating device across the strip width is less than 1°C. This improves the gloss uniformity of the coating across the strip width.

[0084] According to another variation, the heating device 3 sequentially includes a base heater covering the entire width of path P and the aforementioned plurality of heating modules along the path of the moving strip. The base heater can be an infrared heater or a sensor. Due to this design, a portion of the energy required for the wet film to reach the correct temperature at the outlet of the heating device is provided by the base heater. Each of the plurality of heating modules independently provides the remaining energy and can be adjusted as needed.

[0085] The heating device 3 is preferably positioned above the path P to directly heat the wet film applied to the top side of the strip. The heating device may also be positioned above or below the path P to minimize the thermal gradient.

[0086] The coil coating production line 1 also includes an ultraviolet (UV) curing unit 4. The purpose of this unit is to cure the surface of the wet film of the radiation-cured coating. It has been observed that this surface curing produces very fine textures on the film surface, and once the wet film has been fully cured by the electron beam, these textures, combined with the cooperating agents and possibly other charges, contribute to the gloss of the organic coating.

[0087] In one variant, the UV curing apparatus 4 covers the entire width of the path P of the moving strip. In this case, upon exposure to UV, the surface of the wet film is uniformly cured along the width of the strip.

[0088] According to another variation, the UV curing apparatus 4 includes a plurality of UV modules distributed along the width of the path P. In other words, the plurality of UV modules form a row substantially parallel to the width of the path P, i.e., perpendicular to the direction of movement of the strip. For clarity, the UV modules described herein are positioned independently and adjacent to each other, but these UV modules may be physically inseparable from each other. These UV modules may be individually controllable parts of a single UV curing apparatus.

[0089] Due to this design, different widths of the path / strip can be exposed to different UV doses. This helps to correct for and minimize gloss variations across the strip width. Therefore, the heating device preferably comprises multiple heating modules arranged in a row substantially parallel to the width of the path P, each module adapted to heat a width of the strip that is then exposed to the UV light of a UV module. In other words, each width covered by a given UV module corresponds to a width covered by the corresponding heating module.

[0090] UVA and UVB are preferred. UVA is long-range UV radiation between 320 nm and 400 nm. UVB is short-wave UV radiation between 280 nm and 320 nm. Both UVA and UVB can be obtained using conventional arc UV lamps.

[0091] The UV curing unit 4 is preferably movable along the path P of the moving strip. This allows the length between the UV curing unit and the EB curing unit to be adjusted, i.e., extended or shortened. It has been observed that wrinkles or surface roughness induced during UV curing further develop during the time interval between UV curing and EB curing, which affects the gloss of the organic coating.

[0092] In the case of multiple UV modules, each UV module is preferably able to move independently of the other UV modules along path P.

[0093] The coil coating line 1 also includes an electron beam curing unit 5. The purpose of this unit is to cure the wet film of the radiation-curable coating, i.e., to cure along the entire thickness of the wet film. The electron beam curing unit 5 further freezes the surface roughness that appears on the surface of the wet film during UV curing and that further develops during the time interval between UV curing and EB curing. The EB unit typically operates under the following conditions: 100 kV to 200 kV, 20 kGy to 50 kGy, inertized with nitrogen gas at less than 200 ppm O2.

[0094] Preferably, the roll coating line 1 further includes a wet film temperature measuring device 6, which is positioned downstream of the heating device 3 and upstream of the UV curing device 4. This wet film temperature measuring device measures the temperature of the wet film before it enters the UV curing device. The wet film temperature measuring device 6 can measure the temperature of the wet film along the entire width of the path P of the moving strip, or it can measure the temperature over only a portion of the width. Examples of wet film temperature measuring devices include pyrometers, thermal imagers, and thermocouples. The measured temperature can be expressed in °C, °F, or K.

[0095] When a wet film temperature measuring device measures the temperature on only a portion of the width, the measurement results on that portion can be considered relevant enough to manage the gloss across the entire strip width.

[0096] Alternatively, multiple wet film temperature measuring devices are positioned downstream of the heating device 3 and upstream of the UV curing device to cover the entire width of the path P of the moving strip. The multiple wet film temperature measuring devices form a row substantially parallel to the width of the path P. Therefore, the heating device preferably comprises multiple heating modules forming a row substantially parallel to the width of the path P, each heating module being adapted to heat a portion of the strip across a width, the temperature of which is then measured by a wet film temperature measuring device.

[0097] To further improve temperature control of the wet film in the UV curing apparatus, the wet film temperature measuring device 6 and the UV curing apparatus 4 are separated by no more than 2 meters, preferably no more than 1 meter, or the time for measuring the wet film temperature before the wet film is cured in the UV curing apparatus is no more than 4 seconds, preferably no more than 2 seconds. Alternatively or additionally, a portion of the path P of the moving strip located between the wet film temperature measuring device and the UV curing apparatus may be insulated to maintain the wet film at the measuring temperature before it is cured in the UV curing apparatus.

[0098] The roll coating line 1 also includes a gloss measuring device 7 located downstream of the electron beam curing unit 5. This gloss measuring device measures the gloss of the organic coating after EB curing. The gloss measuring device can measure the gloss of the organic coating over the entire width of the moving strip path P, or it can measure the gloss over only a portion of the width. An example of the gloss measuring device is a gloss meter. The measured gloss is preferably expressed in GU (gloss unit). The gloss is preferably measured according to ISO 2813:2014 and EN 13523-2:2021 standards. Preferably, the gloss is measured using a 20° geometry, a 60° geometry, or an 85° geometry, i.e., a reflection angle of 20°, 60°, or 85°. More preferably, the gloss is measured using a 60° geometry.

[0099] When a gloss measuring device measures the gloss on only a portion of the width, the measurement result for that portion can be considered relevant enough to manage the gloss across the entire strip width.

[0100] Alternatively, multiple gloss measuring devices are positioned downstream of the EB curing apparatus to cover the entire width of the path P of the moving strip. These multiple gloss measuring devices form a row substantially parallel to the width of path P. Therefore, the heating apparatus preferably comprises multiple heating modules forming a row substantially parallel to the width of path P, each adapted to heat a width portion of the strip, the gloss of which is then measured by a gloss measuring device. Similarly, the UV curing apparatus preferably comprises multiple UV modules forming a row substantially parallel to the width of path P, each adapted to expose a width portion of the strip to UV light, the gloss of which is then measured by a gloss measuring device.

[0101] The roll coating production line 1 is preferably equipped with a strip speed measuring device, which is more preferably positioned at the level of the guide roller. An example of the strip speed measuring device is a speedometer attached to the roller shaft.

[0102] The roll coating line 1 may also include a sensor 8 upstream of the coating applicator 2. The sensor 8 can heat the strip before it reaches the coating applicator. Warming the strip in the coating applicator facilitates coating application. Furthermore, the temperature reached by the strip in the sensor can be adjusted to correct for possible gloss deviations, as will be described in detail later.

[0103] The roll coating production line 1 may also include an inlet section with an uncoiler 9 for unwinding the strip to be coated on the production line. The uncoiler may be combined with a welding machine or a sewing machine so that the front end of the strip to be coated can be attached to the tail end of the previous strip.

[0104] Alternatively, the coil coating line can be connected to the galvanizing line, so that the strip coated with the metal alloy contained in the galvanizing solution of the galvanizing line is directly coated with the organic coating, without having to first wind the strip and then unwind it.

[0105] The coil coating line 1 may also include an inlet accumulator 10, located in the inlet section of the line, downstream of the uncoiler if applicable. An accumulator is a device that "accumulates" a certain amount of strip. An accumulator is a set of upper and lower rollers through which the metal strip passes in a serpentine manner, and the accumulator stores the length of metal when the two roller rows are separated. The total stored length of metal depends on the design speed of the line, typically a steady-state metal processing time of 60 seconds. When the inlet section of the coil coating line stops, the roller rows move toward each other, and the metal stored in the accumulator continues to supply the remainder of the coil coating line.

[0106] The roll coating line 1 may also include a cleaning section 11, located downstream of the inlet section, particularly downstream of the inlet accumulator, if applicable. In this section, the strip undergoes a surface preparation step. This type of preparation includes at least one step selected from rinsing, degreasing, and conversion treatment. Rinsing aims to remove loose dirt particles, potential residues of the conversion solution, and any soap residues that may have formed, to obtain a clean and reactive surface. Degreasing aims to clean the surface by removing all traces of organic dirt, metal particles, and dust. Preferably, degreasing is performed in an alkaline environment. Conversion treatment involves applying a conversion solution to the strip, which chemically reacts with the surface, thereby allowing the formation of a conversion layer. The conversion layer increases the adhesion and corrosion resistance of the coating. Conversion treatment is preferably an acidic solution that does not contain chromium. More preferably, the conversion treatment is based on hexafluorotitanic acid or hexafluorozirconic acid.

[0107] The coil coating line 1 may also include a primer section, if applicable, located upstream of the coating applicator 2 and downstream of the cleaning section. In this section, a first layer of coating may be applied to the strip to form a primer coating. The primer section may include a primer coating applicator and a curing device. Depending on the nature of the primer, the curing device may be an oven, such as a convection oven, an infrared (or near-infrared) oven, an induction oven, a UV curing device, and / or an EB curing device.

[0108] The roll coating production line 1 may also include an outlet accumulator 12, which is located in the outlet section of the production line and downstream of the EB curing unit. The outlet accumulator is similar to the inlet accumulator described above.

[0109] The coil coating production line 1 may also include a rewinder 13, which rewinds the strip that has already been coated on the production line. The rewinder may be used in conjunction with a cutter to separate the strip from the next strip being processed on the production line.

[0110] The present invention also relates to a gloss management tool for managing the gloss of an organic coating formed by applying a wet film of radiation-curable coating onto a moving strip on a roll coating line 1 and curing the wet film of radiation-curable coating. The roll coating line 1 includes, in sequence along the path P of the moving strip S: a coating applicator 2, a heating device 3 including a heating module, an ultraviolet curing device 4, and an electron beam curing device 5.

[0111] The gloss management tool includes a setting module for setting the gloss value G of organic coatings. s And the setting of the gloss range R for organic coatings. s .

[0112] The gloss management tool also includes a collection module configured to collect measurements G of the gloss of the organic coating in at least one width portion downstream of the electron beam curing apparatus. Preferably, the collection module is further configured to collect measurements T of the temperature of the wet film in at least one width portion downstream of the heating module and upstream of the UV curing apparatus along the moving strip.

[0113] The gloss management tool also includes a calibration module configured to correct measured gloss G that exceeds a set gloss range R. s The deviation is corrected, and this correction includes: using a closed-loop controller, taking into account G. s The measured gloss level G is used to calculate the correction value C for the power to be applied to the heating module. P The sub-steps; and considering the already calculated correction value C. P This is a sub-step to adjust the settings of the roll coating production line.

[0114] Gloss management tools may include a processing unit, which may consist of, for example, a memory and a processor connected to the memory. The electronic monitoring device may also include a display screen and input / output devices, such as a keyboard and mouse, each connected to the processing unit. Each of the setting module, acquisition module, and calibration module can be implemented as processor-executable software.

[0115] The roll coating production line is preferably equipped with a gloss management tool to facilitate the management of gloss on the roll coating production line.

[0116] From a process perspective, managing the gloss of an organic coating formed by applying a wet film of radiation-cured coating to a moving strip on the aforementioned coil coating production line and curing the wet film is primarily based on the finding that the temperature of the wet film prior to UV curing is critical. Specifically, the inventors have observed a potential relationship between the temperature of the wet film prior to UV curing and the gloss of the organic coating after EB curing in the dual-curing process of coil coating. Therefore, by adjusting the power of the heating module and thus the temperature of the wet film prior to UV curing, any deviations in gloss after EB curing can be effectively and repeatably corrected.

[0117] This method is applied to a moving strip. The strip can be a single, unwound roll at the entrance of the roll coating line. More generally, the strip consists of different rolls attached end-to-end. These rolls form a substantially continuous strip whose characteristics and specifications change over time at the exit of the roll coating line. The strip moves along path P of the roll coating line to apply a wet film of radiation-curable coating, preferably subjecting the wet film of radiation-curable coating to heating and double curing. Specifically, the strip moves along path P of the roll coating line such that the wet film of radiation-curable coating is first applied to the strip by a coating applicator, then heated by a heating module, then exposed to UV in an ultraviolet curing apparatus, and finally cured in an electron beam apparatus. Optionally, the strip can be preheated by an inductor 8 located upstream of the coating applicator 2. Optionally, the radiation-curable coating can be heated in the coating applicator.

[0118] Reference Figure 2 A first implementation of the method is described.

[0119] The first step 100 in the method for managing gloss is to set some settings required for proper adjustment.

[0120] First, set the gloss value G for the organic coating. s This value corresponds to the gloss level required by the customer or the roll coating line operator. From a practical standpoint, the set gloss level value G can be manually entered in the gloss management tool, particularly in the setting module. s Alternatively, this value can be automatically obtained from the order book of the roll coating production line, particularly from the scheduling tool.

[0121] Since slight deviations in gloss along the strip length are generally acceptable from a quality perspective, a set gloss range R for the organic coating gloss has also been established. s The set gloss range can be input as a range with minimum and maximum gloss, or it can be used as a set gloss value G.s The standard deviation input. Of course, if slight deviations must be avoided for some reason, then the gloss value G should be set. s This can be used as the minimum and maximum gloss input, or the standard deviation can be set to zero. From a practical point of view, this setting represents the gloss range R. s The gloss range can be manually entered in the gloss management tool, particularly in the settings module. Alternatively, this gloss range can be automatically obtained from the roll coating line's management tool or the roll coating line's order book, especially from the scheduling tool. The gloss setting range R s It can also be obtained from standards such as EN10169:2013.

[0122] In the second step 120 of the method for managing gloss, a measurement value G of the gloss of the organic coating is collected downstream of an electron beam curing apparatus in at least one width portion.

[0123] Preferably, a temperature measurement T of the wet film is also collected downstream of the heating module and in at least one width portion upstream of the moving strip in the UV curing apparatus. More 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.

[0124] Preferably, the measurements are performed within sufficiently short time intervals to allow for proper management of gloss. Examples of time intervals are less than 30 seconds, less than 20 seconds, less than every 10 seconds, less than every 5 seconds, less than every 2 seconds, and less than per second. More preferably, the measurements are substantially continuous or continuous. Preferably, the measurements are collected at sufficiently short time intervals to allow for proper management of gloss. Examples of time intervals are less than every 10 seconds, less than every 5 seconds, less than every 2 seconds, and less than per second. More preferably, the measurements are collected substantially continuously or continuously. Preferably, the measurements are collected in a gloss management tool, particularly in the acquisition module, and more preferably automatically through a suitable interface.

[0125] In the context of "width portion," it means that the moving strip is conceptually divided into portions that are adjacent to each other across the width of the strip. There can be a single width portion or multiple width portions. Therefore, the wet film and the organic coating can also be conceptually divided into the same width portions. In the context of "at least one width portion," it means that the method is implemented over one or more width portions or the entire width of the moving strip. If the method is not implemented over the entire width, then the following can be measured and collected:

[0126] - The gloss G of the organic coating in a single width segment, if the measurement in that width segment is considered relevant enough to manage the gloss across the entire strip width, or

[0127] - The gloss of the organic coating across multiple widths allows the gloss in each width to be managed independently of the others.

[0128] Alternatively, the following can also be measured and collected:

[0129] - The temperature T of the wet film in a single width segment, if the measurement in that width segment is considered sufficient to represent the average temperature over the entire strip width, or

[0130] - The temperature of the wet film in multiple width sections allows the temperature in each width section to be adjusted independently of the other sections.

[0131] In one variant, the collection step is performed after the setting step.

[0132] In another variation, particularly during continuous operation in a coil coating production line, the collection step can be performed concurrently with the setup step. In this continuous operation scenario, variations in strip characteristics and specifications frequently occur because the strip consists of different coils attached end-to-end. While the collection step is underway, any of the setup parameters, especially the gloss value G, are being set. s And / or set the gloss range R s Any of these may need to be modified for some reason—such as a change in the specified gloss level or a change in the radiation-cured coating. Therefore, perform the setup steps.

[0133] Preferably, in the second step 120 of the method for managing gloss, the power PW of the heating module is also collected.

[0134] In the third step 130 of the method for managing gloss, if the measured gloss G exceeds the set gloss range R... s The possible deviations are corrected. First, the measured gloss G is compared with the set gloss value G. s And / or set the gloss range R s Compare the values ​​to assess potential deviations in gloss. If the measured gloss G is still within the set gloss range R... s If the measured gloss level G has deviated from the set gloss level R, then the set value will remain. s Then, using a closed-loop controller, considering G s The measured gloss level G is used to calculate the correction value C for the power to be applied to the heating module. P .

[0135] The evaluation of gloss deviation can be performed at any time. Preferably, the evaluation of gloss deviation is performed over sufficiently short time intervals to allow for proper management of gloss. Examples of time intervals are less than 30 seconds, less than 20 seconds, less than every 10 seconds, less than every 5 seconds, less than every 2 seconds, and less than per second. More preferably, the evaluation is substantially continuous or continuous.

[0136] Calculate the correction value C for the power to be applied to the heating module. P This is accomplished using a closed-loop controller. Preferably, this controller is a proportional-integral-derivative (PI) controller. Since in some cases only one or two terms of the controller can provide adequate control, some parameters of the controller can be set to zero to disable some terms. In particular, at least one of the integral and derivative terms of the PI controller is active. "Active" means that the term is not set to zero or that the term is used for calculation. In other words, the PI controller is preferably a PI controller, PD controller, I controller, D controller, or PID controller.

[0137] Therefore, the correction value C can be calculated using the following general formula. P :

[0138]

[0139] or

[0140]

[0141] Where e is the error, i.e., the difference between the desired setpoint and the measured process variable, t is time or instantaneous time, and τ is the integral variable. Other control functions are well known to those skilled in the art and can be used to control the gloss of organic coatings.

[0142] At the correction value C P In the first variation of the calculation, closed-loop control is directly based on the gloss of the organic coating. In other words, the measured process variable is the measured gloss, and the desired setpoint is G. s In this case, the correction value C P It is G s A function of the difference between the measured gloss level G and the gloss level G.

[0143] Specifically, the correction value C for the power to be applied to the heating module can be calculated according to Equation 1. P :

[0144]

[0145] Among them, K p It is the proportional gain, K i It is the integral gain, Kd It is the differential gain, and e1 is G s The difference between the measured gloss level G and the measured gloss level G.

[0146] In particular, K i >0 and / or K d >0.

[0147] For K p K i and K d The good practices for the initial selection and adjustment of K are well known to those skilled in the art. Therefore, K can be easily selected and adjusted as needed. p K i and K d The initial gain K can be manually entered in the gloss management tool. p K i and K d In particular, these initial gains are manually entered in the setup module. These initial gains can be set during the setup process.

[0148] Alternatively, the correction value C for the power to be applied to the heating module can be calculated according to the following equation. P :

[0149]

[0150] Among them, K p It is the proportional gain, T i It is the integration time, T d It is the differential time, and e1 is G. s The difference between the measured gloss level G and the measured gloss level G.

[0151] Specifically, 1 / T i >0 and / or T d >0.

[0152] For K p T i and T d The good practices for the initial selection and adjustment of K are well known to those skilled in the art. Therefore, K can be easily selected and adjusted as needed. p T i and T d The initial value K can be manually entered in the gloss management tool. p T i and T d In particular, these initial items can be manually entered in the setup module. These initial items can be set during the setup process.

[0153] In the second variation, the collection step further includes collecting a measurement T of the wet film temperature in at least one width of the moving strip downstream of the heating module and upstream of the UV curing apparatus. Since a relationship has been observed between the wet film temperature before UV curing and the gloss of the organic coating after EB curing, closed-loop control of the heating module's power is based on the wet film temperature in at least one width of the moving strip downstream of the heating module and upstream of the UV curing apparatus. In other words, the measured process variable is the measured temperature, and the desired setpoint is the corrected temperature T that the wet film will reach in at least one width of the moving strip downstream of the heating module and upstream of the UV curing apparatus. c To obtain the set gloss value G s .

[0154] Therefore, in the first sub-step of the calibration step, the calibrated temperature T that the wet film will reach in at least one width portion downstream of the heating module and upstream of the UV curing apparatus is calculated. c .

[0155] Generally, the corrected temperature T is calculated according to Equation 2. c :

[0156] T c = f1 (T, G, G) s (2)

[0157] Here, function f1 represents a predetermined mathematical relationship between the temperature of the wet film before UV curing and the gloss of the organic coating after electron beam curing. "Predetermined" means that a calibration step, preferably the calibration step described above, has been performed before implementing the method on the roll-to-roll coating production line.

[0158] The function f1 can be obtained in a calibration step performed before the setup step. During this calibration step, the wet film of the radiation-cured coating used on the coil coating line is heated at different temperatures, cured by double curing under standard curing conditions, and the gloss of the organic coating is measured. Therefore, the function f1 can be derived. This calibration step can be completed in one go and does not need to be performed every time the method according to the invention is implemented. The function f1 can be manually entered in the gloss management tool, particularly in the setup module. Alternatively, the function f1 can be automatically obtained by cross-referencing a predetermined mathematical relationship, possibly tabular in form, entered in the gloss management tool with coating reference values ​​from the order book of the coil coating line, particularly from the scheduling tool. The function f1 can be set during the setup step.

[0159] In particular, it has been observed that for certain commercially available radiation-cured coatings used for coil coating of steel, a linear mathematical relationship exists between the temperature of the wet film before UV curing and the gloss of the organic coating after electron beam curing, as expressed by the following equation:

[0160] T = T0 – KG

[0161] Where K is a proportionality constant.

[0162] In this case, the corrected temperature T is calculated according to Equation 3. c :

[0163] T c = T + K (G – G) s (3)

[0164] The proportionality constant K can be obtained in a calibration step performed prior to the setup step. During this calibration step, the wet film of the radiation-cured coating used on the roll coating line is heated at different temperatures, cured under standard curing conditions via double curing, and the gloss of the organic coating is measured. The proportionality constant K can thus be derived. Depending on the temperature unit, this proportionality constant is preferably expressed in °C / GU, °F / GU, or K / GU. This calibration step can be completed in one step and does not need to be performed every time the method according to the invention is implemented.

[0165] From a practical perspective, during the calibration step, the proportionality constant K is obtained from a predetermined linear mathematical relationship between the temperature of the wet film before UV curing and the gloss of the organic coating after electron beam curing. This predetermined linear mathematical relationship is available to the operators of the coil coating production line. "Predetermined" means that a calibration step, preferably as described above, has been performed before implementing the method on the coil coating production line. The proportionality constant K can be manually entered in a gloss management tool, particularly in the setting module. Alternatively, the proportionality constant can be automatically obtained by cross-referencing the predetermined linear mathematical relationship, possibly in tabular form, entered in the gloss management tool with paint reference values ​​from the coil coating production line order book, particularly from the scheduling tool.

[0166] For example, it has been observed that for some commercially available radiation-cured coatings used for coil coating of steel, K typically ranges between 0.3 and 1.2. More generally, K > 0.

[0167] Once the corrected temperature T has been calculated c According to T c The difference between the measured temperature T and the calculated value C is used to correct the power of the heating module. P .

[0168] In particular, in the case of a parallel proportional-integral-derivative controller, the correction value C can be calculated according to Equation 4. P :

[0169]

[0170] Among them, K' p It is the proportional gain, K' i It is the integral gain, K' d It is the differential gain, and e2 is T c The difference between the measured temperature T and the measured temperature T.

[0171] In particular, K' i >0 and / or K' d >0.

[0172] For K' p K' i and K' d The good practices for the initial selection and adjustment of K' are well known to those skilled in the art. Therefore, K' can be easily selected and adjusted as needed. p K' i and K' d The initial gain K' can be manually entered in the gloss management tool, especially in the settings module. p K' i and K' d These initial gains can be set during the setup process.

[0173] Alternatively, in the case of a standard proportional-integral-derivative controller, the correction value C for the power to be applied to the heating module can be calculated according to the following equation. P :

[0174]

[0175] Among them, K' p It is the proportional gain, T' i It is the integration time, T' d It is the differential time, and e2 is T. c The difference between the measured temperature T and the measured temperature T.

[0176] Specifically, 1 / T' i >0 and / or T' d >0.

[0177] For K' p 、T' i and T' dThe good practices for the initial selection and adjustment of K' are well known to those skilled in the art. Therefore, K' can be easily selected and adjusted as needed. p 、T' i and T' d The initial value K' can be manually entered in the gloss management tool, especially in the settings module. p 、T' i and T' d These initial settings can be configured during the setup process.

[0178] Correction value C P The calculation of this second variation is very convenient, thus avoiding the juxtaposition of interdependent closed-loop controls and controlling the temperature of the wet film to not exceed the maximum temperature T that would degrade the radiation-cured coating. max As will be described in detail later.

[0179] Once the correction value C for the power to be applied to the heating module has been calculated... P Then consider the correction value C. P This is used to adjust the production line settings in order to correct for deviations in the measured gloss.

[0180] Specifically, once the correction value C has been calculated... P Then through the correction value C P The power of the heating module is adjusted. Adjusting the power of the heating module includes turning the heating module on or off. Due to the adjustment of the heating module, the temperature of the wet film downstream of the heating module and upstream of the UV curing apparatus in the width portion is corrected, and a gloss value G on the organic coating is obtained downstream of the electron beam curing apparatus in the width portion. s The power adjustment of the heating module can be done manually by the operator or automatically with the help of gloss management tools, especially the calibration module.

[0181] Alternatively, in the case where a sensor is installed upstream of the coating applicator on the coil coating line, once the correction value C has been calculated... P The power of the sensor is adjusted to regulate the temperature of the strip at the level of the coating applicator, so that a gloss value G on the organic coating is obtained in at least one width of the moving flow downstream of the electron beam curing apparatus. s If in calculating the correction value C p The corrected temperature T has already been calculated. c Then, the power of the sensor is adjusted so that the wet film reaches a calibrated temperature T in at least one width of the moving strip downstream of the cooling / heating module and upstream of the UV curing apparatus. cThis alternative method for correcting gloss is particularly useful when the heating module is already at maximum capacity and the temperature of the wet film upstream of the UV curing unit must be further increased. The overheating provided by the heating module is reduced by further heating the strip in the inductor.

[0182] In one variant, a correction step 130 is performed after the collection step 120.

[0183] In another variation, particularly during continuous operation in a coil coating production line, the calibration step can be performed concurrently with the collection step. In this continuous operation scenario, variations in strip characteristics and specifications frequently occur because the strip consists of different coils attached end-to-end. These variations can cause deviations in gloss. The calibration step is performed simultaneously with the collection step to correct the measured gloss.

[0184] Optionally, the method further includes step 110, during which initial production line conditions are set. This step is referred to as the initial production line setup step. As described above, the method causes the measured gloss to exceed a set gloss range R. s Any deviations are corrected. That is, at the start of production on the coil coating line or after significant changes, such as in strip specifications, coating thickness, coating color, or line speed, the line conditions may deviate from what is suitable for achieving the set gloss value G. s The production line conditions may vary. In such cases, the heating module may not heat properly and / or it may take some time to reach the calibration value C. T The corresponding power and / or the power of the heating module may be insufficient to bring the wet film to the corrected temperature T. c Therefore, a portion of the coated strip may have to be scrapped due to gloss exceeding specifications. Furthermore, the UV dose required to achieve the set gloss value for the wet film's surface roughness may not be suitable. In this case, the heating module needs to compensate for the offset UV dose, which can be done through intense heating, but this takes time. Similarly, a portion of the coated strip may have to be scrapped due to gloss exceeding specifications. To minimize the length of coated strip exceeding specifications, it is advantageous to set initial production line conditions.

[0185] Therefore, in the first sub-step, multiple process parameters and / or specifications of the coated strip are collected. Examples of process parameters include the initial line speed LS0. This initial line speed is preferably the recommended speed for the next roll to be coated on the roll coating line. Another example is the initial thickness FTh0 of the wet film applied to the strip by the paint applicator. This initial film thickness is preferably a thickness corresponding to the specified organic coating thickness for the next roll to be coated on the roll coating line. Another example is the temperature of the moving strip before the paint applicator, preferably before the sensor. Examples of specifications include the initial strip thickness STh0, the initial strip width SWd0, and the paint color. Preferably, the initial line speed LS0, initial thickness FTh0, initial strip thickness STh0, initial strip width SWd0, and paint color are collected. From a practical perspective, process parameters and / or specifications can be manually entered in the gloss management tool, particularly in the settings module. Alternatively, process parameters and / or specifications can be automatically obtained from the order book of the roll coating line, particularly from the scheduling tool and / or inferred from the order book. For example, the initial film thickness FTh0 can be inferred from the organic coating thickness specified in the order book.

[0186] Once the process parameters and / or specifications have been collected, the initial production line conditions are set in the second sub-step, taking into account the collected process parameters and / or specifications. Specifically, the initial production line conditions are calculated based on the collected process parameters and / or specifications. The following initial production line conditions can be set:

[0187] -The initial power PW0 of the heating module,

[0188] - Initial UV dose D0 of the UV curing device or UV module (if applicable),

[0189] - The initial length L0 between the UV curing unit or UV module (if applicable) and the electron beam curing unit.

[0190] Given the mass flow rate of the moving strip, the specific heat capacity of the strip, and the heating output, the initial power PW0 can be set. The initial UV dose D0 can be set based on data obtained from a calibration step performed prior to the initial production line setup step. The initial length L0 can be set based on data obtained from a calibration step performed prior to the initial production line setup step.

[0191] From a practical standpoint, initial production line conditions can be manually entered in the management tools for coil coating production lines. Alternatively, initial production line conditions can be automatically added using the gloss management tool within the coil coating production line management tools.

[0192] In one variation, the initial production line setup step 110 is performed before setup step 100. This includes setting the gloss value G.s and setting the gloss range R s In addition to the initial combination, the initial production line setup step 110 also helps to start production under production line conditions that have already been optimized for the first roll of material for the production activity. During production, collection and correction steps can be performed to manage gloss. When setting any of the parameters, particularly setting the gloss value G... s And / or set the gloss range R s If either of these must be modified for any reason—such as a change in the specified gloss or a change in the radiation-cured coating—then the execution of the collection step 120 and the correction step 130 is relied upon to maintain the measured gloss within the set gloss range R. s Inside.

[0193] In another variation, such as Figure 2 As illustrated, initial production line setup step 110 is performed after setup step 100. This allows for consideration of setting the gloss value G. s This completes the initial production line conditions setup. Therefore, the production line conditions are better optimized for the first roll of material produced. Furthermore, during production, when any of the settings parameters are set, particularly the gloss value G... s And / or set the gloss range R s If any of them must be modified for any reason, the initial production line settings can be reset to help minimize the transition period.

[0194] In another variation, the initial production line setup step 110 is performed before and after the setup step 100 to take advantage of the advantages of the two variations described above.

[0195] In another variation, particularly during continuous operation of a coil coating production line, the initial line setup step can be performed in parallel with the collection step. In this continuous operation scenario, because the strip consists of different coils attached end-to-end, variations in strip characteristics and specifications frequently occur. When one of these variations occurs, re-initializing the line conditions helps to reach the set gloss value as quickly as possible.

[0196] Now refer to Figure 3 A second embodiment of the method is described.

[0197] The main difference between this implementation and the first implementation is that the correction step includes additional sub-steps so as to:

[0198] - Ensure that the temperature of the wet film upstream of the UV curing unit does not exceed the highest temperature (T) that would degrade the radiation-cured coating. max ,and

[0199] - Correct the deviation of the measured gloss G accordingly.

[0200] This configuration further prevents thermal degradation of the wet film when it is heated in the heating module.

[0201] The details provided in describing the first embodiment apply to the second embodiment. The additional steps and corresponding features will now be described in detail.

[0202] Setting step 100 also includes setting the maximum temperature T for the radiation-cured coating. max This temperature can be the one recommended by the paint supplier. Alternatively, it can be determined by the operator of the coil coating line, particularly by measuring the functional relationship between paint monomer emission and temperature. This measurement can be performed offline or at the level of the heating module on the production line. From a practical standpoint, the maximum temperature T can be manually entered in the gloss management tool, especially in the settings module. max Alternatively, the maximum temperature T can be automatically obtained by cross-referencing different maximum temperatures entered in the gloss management tool with coating reference values ​​from the order book of the coil coating production line, particularly from the scheduling tool. max .

[0203] Step 120 includes collecting a measurement of the temperature T of the wet film in at least one width portion downstream of the heating module and upstream of the UV curing apparatus and on the moving strip.

[0204] Step 120 also includes collecting the UV dose D of the UV module. The power of the UV module is typically known to the operator and can be obtained from the roll-to-roll coating line's management tools; however, for a given power, the actual UV dose exposed to the wet film varies with the line speed LS. Therefore, the UV dose is calculated and collected based on the UV module's power and the line speed. The line speed itself is typically known to the operator and can be obtained from the roll-to-roll coating line's management tools.

[0205] Preferably, the UV dose is recalculated and collected each time the power of the UV module and / or the production line speed is adjusted. More preferably, the collection of the UV dose is substantially continuous. Preferably, the UV dose is collected in a gloss management tool, particularly in a collection module, and more preferably automatically through a suitable interface.

[0206] During correction step 130, if the correction value C is calculated... p The corrected temperature T has already been calculated. c , then T c With the highest temperature T maxA comparison is then made. Alternatively, the correction step may include calculating the corrected temperature T that the wet film will reach in at least one width portion downstream of the heating module and upstream of the UV curing apparatus. c This is a sub-step that can be used to calculate the correction value C. p Then, or at any other appropriate time, complete it. Once this sub-step is complete, T can be... c With the highest temperature T max Comparison. Alternatively, T can be compared with the highest temperature T. max Compare them.

[0207] If T c (or T) is lower than T max The power of the heating module is adjusted by the correction value C. P Adjustments are made as detailed in the first embodiment.

[0208] If T c (or T) is higher than T max Therefore, gloss must be corrected without further increasing the power of the heating module. One approach to this is to adjust the power of the UV module, particularly by increasing it. It has been observed that the power of the UV module affects the gloss of the organic coating. The greater the increase in the UV dose on the wet film, the greater the decrease in gloss. Therefore, correction step 130 also includes calculating, according to Equation 5, a correction value C for the UV dose that must be exposed to the wet film in at least one width of the moving strip within the UV module. D :

[0209] C D = f2 (G, G s (5)

[0210] Equation (5) can be obtained in a calibration step performed before the calibration step, preferably before the setup step. During this calibration step, the wet film of the radiation-cured coating to be used on the roll coating line is exposed to different UV doses, cured by EB under standard curing conditions, and the gloss of the organic coating is measured. Therefore, function f2 can be deduced for each radiation-cured coating. This calibration step can be completed in one go and does not need to be performed every time the method according to the invention is implemented. Alternatively, function f2 can be G s A PID function for the difference between the measured gloss level G and the measured gloss level G.

[0211] Preferably, during the setup step, a function f2 is set to establish a predetermined mathematical relationship between the UV dose exposed to the wet film of the radiation-cured coating and the gloss of the organic coating after electron beam curing. "Predetermined" means that a calibration step, preferably as described above, has been performed before implementing the method on the coil coating production line. The function f2 can be manually entered in the gloss management tool, particularly in the setup module. Alternatively, the function f2 can be automatically obtained by cross-referencing the predetermined mathematical relationship entered in the gloss management tool with coating reference values ​​from the order book of the coil coating production line, particularly from the scheduling tool.

[0212] For example, it has been observed that for commercially available radiation-cured coatings used for coil coating of steel, f2 is typically associated with a gloss profile that tends to decrease asymptotically with increasing UV dose.

[0213] Once the correction value C to be applied to the UV dose has been calculated... D Considering the already calculated correction value C D Adjust production line settings, except for the power of the heating module and the sensor (if applicable), to correct for deviations in the measured gloss.

[0214] exist Figure 3 In the variant illustrated, once the correction value C to be applied to the UV dose has been calculated... D Adjusting the power of the UV module, particularly increasing the power of the UV module, so that the wet film is exposed to a UV dose D in at least one width portion of the moving strip within the UV module. c =D+C D Due to the adjustment of the UV module, the UV dose exposed to the wet film in the width portion of the UV module is corrected, and a gloss value G on the organic coating is obtained in the width portion downstream of the electron beam curing apparatus. s The UV module power can be adjusted manually by the operator or automatically using gloss management tools.

[0215] Now refer to Figure 4 A third embodiment of the method is described.

[0216] The main difference between this embodiment and the second embodiment is that the correction step includes an additional sub-step so that:

[0217] - Ensure the UV dose does not exceed the maximum UV dose that the wet film can be exposed to. max ,

[0218] - Correct the deviation of the measured gloss G accordingly.

[0219] This configuration further prevents the wet film from being over-cured in the UV curing apparatus, which could adversely affect gloss.

[0220] The details provided in describing the first and second embodiments apply to the third embodiment. The additional steps and corresponding features will now be described in detail.

[0221] In this embodiment, the UV module of the UV curing unit in the roll coating production line can move along path P. Therefore, the length L between the UV module and the electron beam curing unit can be adjusted.

[0222] Setting step 100 also includes setting the maximum UV dose D that the wet film can be exposed to in the UV module. max The UV dose can be the dose recommended by the coating supplier. Alternatively, the UV dose can be determined by the operator of the coil coating production line, particularly during the calibration step. From a practical standpoint, the maximum UV dose D can be manually entered in the gloss management tool, especially in the settings module. max Alternatively, the maximum UV dose D can be automatically obtained by cross-referencing different maximum UV doses entered in the gloss management tool with coating reference values ​​from the order book of the roll coating production line, particularly from the scheduling tool. max .

[0223] Step 120 also includes collecting the length L between the UV module and the electron beam curing device. This length is typically known to the operator or can be determined by management tools on the roll-to-roll coating line. This length can be collected manually. Preferably, this length is collected in a gloss management tool, more preferably automatically through a suitable interface. Preferably, the length L is collected only when it is modified.

[0224] During correction step 130, once the correction value C to be applied to the UV dose has been calculated... D Then D+C D The sum (hereinafter referred to as D) c ) and maximum UV dose D max Compare. If D c Below D max Then adjust the power / setting of the UV module so that the wet film is exposed to UV dose D in at least one width portion of the moving strip within the UV module. c Due to the adjustment of the UV module, the UV dose exposed to the wet film in the width portion of the UV module is corrected, and a gloss value G on the organic coating is obtained in the width portion downstream of the electron beam curing apparatus. s As in the second embodiment.

[0225] If Dc Higher than D max Therefore, gloss must be corrected without further increasing the UV dose of the UV module. One approach to this is to adjust the length between the UV module and the electron beam curing device, particularly by extending this length. It has been observed that this length affects the gloss of the organic coating. The longer the time between UV curing and EB curing, the lower the gloss. Therefore, correction step 130 also includes calculating a correction value C to be applied to the length L between the UV module and the electron beam curing device according to Equation 6. L :

[0226] C L = f3 (G, G s (6)

[0227] Equation (6) can be obtained in a calibration step performed before the calibration step, preferably before the setup step. During this calibration step, the wet film of the radiation-cured coating to be used on the roll coating production line is sequentially exposed to UV curing and EB curing under standard curing conditions, with different times between the two curing processes, and the gloss of the organic coating is measured. Therefore, a function f3 can be deduced for each radiation-cured coating. This calibration step can be completed in one go and does not need to be performed every time the method according to the invention is implemented. Alternatively, the function f3 can be G s A PID function for the difference between the measured gloss level G and the measured gloss level G.

[0228] Preferably, during the setup step, a function f3 is set to represent a predetermined mathematical relationship between the length between the UV module and the electron beam curing apparatus and the gloss of the organic coating after electron beam curing. "Predetermined" means that a calibration step, preferably as described above, has been performed before implementing the method on the roll-to-roll coating production line. The function f3 can be manually entered in the gloss management tool, particularly in the setup module. Alternatively, the function f3 can be automatically obtained by cross-referencing the predetermined mathematical relationship entered in the gloss management tool with coating reference values ​​from the roll-to-roll coating production line's order book, particularly from the scheduling tool.

[0229] For example, it has been observed that for commercially available radiation-cured coatings used for coil coating of steel, f3 is generally associated with a gloss profile that tends to decrease asymptotically as L increases.

[0230] Once the correction value C to be applied to the length between the UV module and the electron beam curing device has been calculated... L Considering the already calculated correction value C L Adjust production line settings, except for the power of the heating module, the sensor (if applicable), and the UV module, to correct for deviations in the measured gloss.

[0231] exist Figure 4 In the variant illustrated, once the correction value C has been calculated... L The length between the UV module and the electron beam curing device is adjusted, especially extended to the calibrated length L. c =L+C L Thus, a gloss value G is obtained on the organic coating in at least one width portion downstream of the moving strip in the electron beam curing apparatus. s The length can be adjusted manually by the operator or automatically using a gloss management tool.

[0232] Alternatively, particularly if the length between the UV module and the electron beam curing unit cannot be further increased or decreased, the production line speed can be adjusted. In this case, the initial production line settings can be executed again to adjust to the new production line speed, the initial power PW0 of the heating module, the initial UV dose D0 of the UV curing unit, and the initial length L0 between the UV curing unit and the electron beam curing unit.

[0233] The present invention also relates to a method for forming an organic coating on a moving strip in a roll coating production line, the roll coating production line comprising, in sequence along the path P of the moving strip: a coating applicator, a heating device including a heating module, an ultraviolet curing device, and an electron beam curing device, the method comprising the following steps:

[0234] - Apply a wet film of radiation-cured coating onto the moving strip using a coating applicator.

[0235] - The wet film of the radiation-cured coating is heated in the heating module.

[0236] - Expose the wet film of the radiation-curable coating to UV light in an ultraviolet curing device.

[0237] - The wet film of the radiation-curable coating is cured in an electron beam device to form an organic coating.

[0238] The gloss of organic coatings is managed through the following methods:

[0239] - Set the gloss value G for the organic coating. s And the setting of the gloss range R for organic coatings. s ,

[0240] -Measurements of the gloss G of the organic coating are collected downstream of the electron beam curing apparatus in at least one width portion.

[0241] - For measured glossiness G that exceeds the set glossiness range R s The deviation is corrected, and the correction steps include: using a closed-loop controller, considering Gs The measured gloss level G is used to calculate the correction value C for the power to be applied to the heating module. P The sub-steps; and considering the already calculated correction value C. P This is a sub-step to adjust the settings of the roll coating production line.

[0242] All the details provided regarding the methods for managing gloss and all the details provided regarding the roll coating production line are applicable to methods for forming organic coatings.

[0243] The present invention also relates to a method for manufacturing pre-coated metal on a coil coating production line, the pre-coated metal comprising a metal strip and an organic coating, the coil coating production line comprising, in sequence along a path P of moving metal strip: a coating applicator, a heating device including a heating module, an ultraviolet curing device, and an electron beam curing device, the method comprising the following steps:

[0244] - Apply a wet film of radiation-cured coating onto a moving metal strip using a coating applicator.

[0245] - The wet film of the radiation-cured coating is heated in the heating module.

[0246] - Expose the wet film of the radiation-curable coating to UV light in an ultraviolet curing device.

[0247] - The wet film of the radiation-curable coating is cured in an electron beam device to form an organic coating.

[0248] The gloss of organic coatings is managed through the following methods:

[0249] - Set the gloss value G for the organic coating. s And the setting of the gloss range R for organic coatings. s ,

[0250] -Measurements of the gloss G of the organic coating are collected downstream of the electron beam curing apparatus in at least one width portion.

[0251] - For measured glossiness G that exceeds the set glossiness range R s The deviation is corrected, and the correction steps include: using a closed-loop controller, considering G s The measured gloss level G is used to calculate the correction value C for the power to be applied to the heating module. P The sub-steps; and considering the already calculated correction value C. P This is a sub-step to adjust the settings of the roll coating production line.

[0252] All the details provided regarding the methods for managing gloss and all the details provided regarding the coil coating production line are suitable for methods for manufacturing pre-coated metal.

Claims

1. A method for managing the gloss of an organic coating, said organic coating being formed by applying a wet film of a radiation-cured coating onto a moving strip on a coil coating line and curing said wet film of the radiation-cured coating, said coil coating line comprising, sequentially along a path P of said moving strip: The method comprises the following steps: a coating applicator, a heating device including a heating module, an ultraviolet curing device, and an electron beam curing device; the coating applicator includes a heating device including a heating module; an ultraviolet curing device; and an electron beam curing device. - Set the set gloss value G of the organic coating. s And the set gloss range R of the gloss of the organic coating. s , - The gloss measurement value G of the organic coating is collected downstream of the electron beam curing apparatus in at least one width portion. - The measured gloss level G exceeds the set gloss level range R. s The deviation is corrected, and the correction step includes: using a closed-loop controller, considering G... s The measured gloss level G is used to calculate the correction value C for the power to be applied to the heating module. P The sub-steps; and considering the already calculated correction value C. P This is a sub-step to adjust the settings of the roll coating production line.

2. The method according to claim 1, wherein, The closed-loop controller is a proportional-integral-derivative controller.

3. The method according to any one of claims 1 or 2, wherein, The correction value C P It is G s A function of the difference between the measured gloss level G and the gloss level G.

4. The method according to any one of claims 1 to 3, wherein, The correction value C to be applied to the power of the heating module is calculated according to Equation 1. P : Among them, K p It is the proportional gain, K i It is the integral gain, K d It is the differential gain, and e1 is G s The difference between the measured gloss level G and the value of the ...

5. The method according to any one of claims 1 or 2, wherein, The collection step further includes collecting a temperature measurement T of the wet film in at least one width portion downstream of the heating module and upstream of the UV curing apparatus and above the moving strip, wherein the correction step further includes calculating a corrected temperature T that the wet film will reach downstream of the heating module and upstream of the at least one width portion and above the UV curing apparatus. c Sub-steps.

6. The method according to claim 5, wherein, The corrected temperature T is calculated according to Equation 2. c : T c =f1(T,G,G s ) (2) Wherein, function f1 is a predetermined mathematical relationship between the temperature of the wet film before UV curing and the gloss of the organic coating after electron beam curing.

7. The method according to claim 5, wherein, The corrected temperature T is calculated according to Equation 3. c : T c =T+K(G-G s ) (3) 8. The method according to any one of claims 5 to 7, wherein, The correction value C P It is T c A function of the difference between the measured temperature T and the actual temperature T.

9. The method according to any one of claims 5 to 7, wherein, The correction value C to be applied to the power of the heating module is calculated according to Equation 4. P : Among them, K' p It is the proportional gain, K' i It is the integral gain, K' d It is the differential gain, and e2 is T c The difference between the measured temperature T and the measured temperature T.

10. The method according to any one of claims 1 to 9, wherein, The sub-step of adjusting the settings of the coil coating production line includes using the correction value C. P To adjust the power of the heating module.

11. The method according to any one of claims 5 to 9, wherein: - The ultraviolet curing device includes a UV module. The setting step also includes setting the maximum temperature T for the radiation-cured coating. max , The collection step further includes collecting the UV dose D of the UV module. - The sub-step of adjusting the settings of the roll coating production line includes: ○Assessment T c Does it exceed T? max , ○If T c Not exceeding T max Then, through the correction value C P To adjust the power of the heating module, ○If T c More than T max ,but: ■ Calculate the correction value C for the UV dose that the wet film must be exposed to in at least one width portion of the UV module according to Equation 5. D : C D =f2(G,G s ) (5) ■ Considering the calculated correction value C D The settings of the roll coating production line, excluding the power of the heating module, are adjusted.

12. The method according to claim 11, wherein, The sub-step of adjusting the settings of the roll coating line, other than the power of the heating module, includes adjusting the power of the UV module such that the wet film is exposed to a corrected UV dose D in at least one width portion of the moving strip. c =D+C D .

13. The method according to claim 11, wherein: - The UV module is capable of moving along the path P. The setting step also includes setting the maximum UV dose D that the wet film can be exposed to in the UV module. max , The collection step further includes collecting the length L between the UV module and the electron beam curing device. - The sub-step of adjusting the settings of the roll coating production line, excluding the power of the heating module, includes: ■Assess D+C D Does it exceed D? max , ■If D+C D Not exceeding D max Then the power of the UV module is adjusted so that the wet film is exposed to the corrected UV dose D in at least one width portion of the moving strip. c =D+C D , ■If D+C D More than D max ,but: ●Calculate the correction value C for the length to be applied between the UV module and the electron beam curing device according to Equation 6. L : C L =f3(G,G s ) (6) ●Consider the calculated correction value C L The settings of the roll coating production line, except for the power of the heating module and the power of the UV module, are adjusted.

14. The method according to claim 13, wherein, The sub-step of adjusting the settings of the roll coating production line, excluding the power of the heating module and the UV module, includes adjusting the length between the UV module and the electron beam curing device to a calibrated length L. c =L+C L In order to obtain a gloss value G on the organic coating in at least one width portion of the moving strip downstream of the electron beam curing apparatus. s .

15. A coil coating production line, the coil coating production line comprising, in sequence: The coil coating line includes a coating applicator, a heating device including a heating module, an ultraviolet curing device, and an electron beam curing device. It also includes a gloss management tool for managing the gloss of an organic coating formed by applying a wet film of radiation-cured coating onto a moving strip on the coil coating line and curing the wet film. The gloss management tool includes: - Setting module, the setting module sets the set gloss value G of the organic coating. s And the set gloss range R of the gloss of the organic coating. s , - A data acquisition module that collects a measurement value G of the gloss of the organic coating in at least one width portion downstream of the electron beam curing apparatus. - A calibration module, which corrects for measured gloss levels G that exceed the set gloss range R. s The deviation is corrected, the correction including: using a closed-loop controller, considering G... s The measured gloss level G is used to calculate the correction value C for the power to be applied to the heating module. P The sub-steps; and considering the already calculated correction value C. P This is a sub-step to adjust the settings of the roll coating production line.

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