RU2846030C2 - Method of coating gloss monitoring on coil rolling coating application line - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to automated processes for continuous application of coating on metal before making finished product and a method of controlling lustre of an organic coating formed on a moving strip of a coil coating application line. Proposed method comprises the following stages: 1) installation of specified value G_s of lustre of organic coating, specified range R_s lustre and constants K of proportionality to preset linear mathematical relationship between wet film temperature before ultraviolet curing and lustre, wherein constant K is obtained during preliminary calibration; 2) collecting data for measuring temperature T of the wet film on at least a portion of the width of the moving strip upstream of the ultraviolet curing device and acquisition of organic coating gloss measurement data G; 3) correcting the deviation of the measured gloss G beyond the specified gloss range R_s, this step includes a sub-step of calculating the corrected temperature T_c, which must reach the wet film in said width section upstream of the ultraviolet curing device, according to the equation T_c = T + K (G – G_s). Any deviation of gloss after electron-beam curing is reproducibly corrected by controlling the temperature of the wet film before UV curing.

EFFECT: efficient and reproducible correction of lustre of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip of a coating application line for rolled metal.

21 cl, 5 dwg

Description

The present invention relates to a method for monitoring the gloss of an organic coating applied to a moving strip on a coil coating line. In particular, the moving strip is a steel strip with a metallic coating.

Coil coating is a continuous automated process for coating metal prior to manufacturing the final product. The steel or aluminum base material is supplied in coils from rolling mills. The metal coil is positioned at the start of the coating line and in one continuous process the coil is unwound, pre-cleaned, pre-treated, pre-primed and pre-painted before being wound at the other end and packaged for shipment.

The product obtained from this process is pre-painted metal, also called coil coated metal, pre-finished metal, or pre-coated metal. It is widely used in construction as well as in home appliances.

The paints traditionally used for coating coils are solvent-based. However, interest has recently been gained in radiation curing, which is the curing of materials using ultraviolet light (UV processes) or electron beam (electron beam curing processes). The corresponding paints, known as radiation-curable paints, are solvent-free and the curing process is initiated either by exposure to high-energy UV radiation, possibly in combination with suitable photoinitiators, or by exposure to accelerated electrons. Photoinitiators absorb the UV radiation and generate free radicals. The latter react with the double bonds of the monomers, causing a chain reaction and polymerization. UV-C and electron beam (EB, electron beam) curing do not require initiators. The energy of the high-energy radiation produces sufficient reactive species (radicals) for polymerization to occur spontaneously.

One of the characteristics of radiation-cured paints is the formation of organic coatings with high gloss due to the high surface tension of the coating. In order to reduce this gloss and meet the requirements of the pre-coated market (gloss is usually between 15 and 30 gloss units (GU) for the construction market), paint suppliers add matting agents, as in solvent-based paints. However, since radiation-cured paints are quite viscous due to the absence of solvent, only a small amount of matting agent can be added, which does not allow a low gloss level to be achieved. In addition, 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 radiation-cured paints compared to solvent-based paints (1-2 seconds versus 12-25 seconds).

One way to mitigate this problem is known from WO 81/00683, which discloses a curing process in which the coating is first irradiated with curing radiation of wavelengths to which the coating responds, but which substantially does not have wavelengths below about 300 nm (e.g. UV), and then irradiated with curing radiation of wavelengths to which the coating responds and which includes substantial radiation of wavelengths below 300 nm (e.g. EB - electron beam). Such a dual curing process is known as dual curing. Gloss control is achieved by adjusting on-line parameters including the spectral distribution, intensity, or dose of the initial radiation, or the time interval between the initial and subsequent irradiation steps.

However, it was observed that these online parameters are not sufficient to effectively control gloss in a reproducible manner.

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

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

- set the specified value G _s of the gloss of the organic coating, the specified range R _s of the gloss of the organic coating and the constant K of proportionality of the specified linear mathematical relationship between the temperature of the wet film before ultraviolet curing and the gloss of the organic coating after electron beam curing,

- collecting the results of measuring the temperature T of the wet film at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, and collecting the results of measuring the gloss G of the organic coating in at least said section of the width downstream of the electron beam curing device,

- correcting the deviation of the measured gloss G outside the specified gloss range _Rs , wherein this correction step includes a sub-step of calculating the corrected temperature _Tc that must be achieved for the wet film in at least the specified width section downstream of the infrared heater and upstream of the ultraviolet curing device, according to equation 1:

T _s = T + K (G - G _s ) ... (1)

The method according to the invention may also have the optional features listed below, considered individually or in combination:

- calculation of the corrected temperature T _c , which is a sub-stage of the correction stage,

- the adjustment stage includes a sub-stage of adjusting the settings of the coating line on the rolled metal product taking into account the calculated adjusted temperature T _c ,

- the method includes the initial line setup stage, during which:

- collect a set of process parameters and/or technical characteristics of the strip,

- at least one initial condition for the line is established from the following conditions: the initial power PW ₀ of the infrared heater, the initial dose D ₀ of the UV radiation of the ultraviolet curing device and the initial length L ₀ between the ultraviolet curing device and the electron beam curing device, taking into account the specified collected process parameters and/or technical characteristics of the strip,

- the adjustment step includes adjusting the power of the infrared heater so that the wet film reaches the adjusted temperature T _c on at least the specified section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device,

- a line for applying a coating to a rolled product includes an inductor upstream of the paint application device, wherein the correction step includes adjusting the power of the inductor so that the wet film reaches a corrected temperature T _c on at least the specified section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device,

- the ultraviolet curing device contains a UV radiation module,

- the installation stage also includes setting the maximum temperature T _max for the specified radiation-curable paint,

- the data collection stage also includes the collection of data on the UV dose D of the UV module,

- the adjustment stage also includes sub-stages, in which:

evaluate whether T _c exceeds T _max ,

if not exceeded, adjust the power of the infrared heater so that the wet film reaches the corrected temperature T _c over at least the specified portion of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device,

if T _c exceeds T _max :

• calculate the corrected UV dose D _c that the wet film over at least the specified width section should receive in the UV module according to equation 2:

D _c = f ₁ (D, G, G _s ) ... (2)

- the adjustment stage also includes a sub-stage of adjusting the setting of the coating line on the rolled product, other than the power of the infrared heater, taking into account the calculated adjusted dose D _of UV radiation,

- the adjustment step also includes adjusting the power of the UV radiation module in such a way that the wet film on at least said portion of the width of the moving strip is exposed to irradiation until an adjusted dose D _c of UV radiation is obtained,

- the UV radiation module can move along the path P,

- the installation stage also includes setting the maximum dose D _max of UV radiation that the wet film can receive in the UV module,

- the collection step additionally includes collection of the length value L between the UV radiation module and the electron beam curing device,

- the adjustment stage also includes sub-stages, in which:

if T _c exceeds T _max :

• evaluate whether D _c exceeds the value of D _max ,

• if it does not exceed, adjust the power of the UV radiation module so that the wet film at least over a section of the width of the moving strip receives the corrected dose D _c of UV radiation,

• if D _c exceeds D _max , calculate the corrected length L _c between the UV module and the electron beam curing device according to equation 3:

L _c = f ₂ (L, G, G _s ) ... (3)

- the adjustment stage also includes a sub-stage of adjusting the setting of the coating line on the rolled product, other than the power of the infrared heater and the power of the UV radiation module, taking into account the calculated adjusted length L _c ,

- the adjustment step also includes adjusting the length between the UV radiation module and the electron beam curing device to the adjusted length L _c so that a gloss with a value of G _s is obtained on the organic coating on at least the specified section of the width of the moving strip downstream of the electron beam curing device,

- the heating device comprises a set of infrared heaters IR, IR', IR''…IR ⁱ , forming a row essentially parallel to the width of the path P,

- the data collection step includes collecting measurements of the temperature T, T', T'' … T ^{i of} the wet film in a set of sections P, P', P'' … P ⁱ of the width of the moving strip downstream of the infrared heaters and upstream of the ultraviolet curing device, as well as collecting measurements of the gloss G, G', G'' … G ⁱ of the organic coating in the specified set of sections P, P', P'' … P ⁱ of the width downstream of the electron beam curing device,

- the correction step includes, for any section P ⁱ of width, independently of other sections, the correction of the deviation of the measured gloss G ⁱ beyond the specified gloss range R _s by calculating the corrected temperature T _c ⁱ , which must be achieved by the wet film in the section P ⁱ of width downstream of the infrared heater IR ⁱ and upstream of the ultraviolet curing device, in accordance with the equation:

T _c ⁱ = T ⁱ + K (G ⁱ - G _s ) … (1 ⁱ )

- the adjustment stage also includes a sub-stage of adjusting the settings of the coating line on the rolled metal product taking into account the calculated adjusted temperature T _c ⁱ ,

- the correction step includes adjusting the power of the infrared heater IR ⁱ in such a way that the wet film reaches the corrected temperature T _c ⁱ in the section P ⁱ of the width of the moving strip downstream from the infrared heater IR ⁱ and upstream from the ultraviolet curing device.

- the ultraviolet curing device comprises a set of UV, UV', UV'' … UV ⁱ UV radiation modules forming a row essentially parallel to the path width P,

- the installation stage also includes setting the maximum temperature T _max for the specified radiation-curable paint,

- the data collection stage contains the collection of data on the doses D, D', D'' … D ⁱ of UV radiation of the UV radiation modules,

- the adjustment stage also includes sub-stages, in which:

evaluate whether T _c ⁱ exceeds T _max ,

if it does not exceed, adjust the power of the infrared heater IR ⁱ so that the wet film reaches the corrected temperature T _c ⁱ in the section P ⁱ of the width of the moving strip downstream of the infrared heater IR ⁱ and upstream of the ultraviolet curing device,

if T _c ⁱ exceeds T _max :

• calculate the corrected dose D _c ⁱ of UV radiation that the wet film should receive in a section P ⁱ of width in the UV ⁱ module, according to equation 2 ⁱ :

D _c ⁱ = f ₁ (D ⁱ , G ⁱ , G _s ) … (2 ⁱ )

- the adjustment stage also includes a sub-stage of adjusting the setting of the coating line on the rolled product, different from the power of the infrared heater IR ⁱ , taking into account the calculated adjusted dose D _c ⁱ of UV radiation,

- the correction stage includes adjusting the power of the UV ⁱ UV radiation module in such a way that the wet film in the section P ⁱ of the width of the moving strip receives the corrected dose D _c ⁱ of UV radiation,

- UV radiation modules can move along the path P independently of each other,

- the installation stage includes setting the maximum dose D _max of UV radiation that the wet film can receive in the UV radiation modules,

- the data collection stage includes the collection of length values L, L', L'' … L ⁱ between the UV radiation modules and the electron beam curing device,

- the adjustment stage includes sub-stages, at which:

if T _c ⁱ exceeds T _max :

• evaluate whether D _c ⁱ exceeds the value D _max ,

• if it does not exceed, adjust the power of the UV ⁱ UV radiation module so that the wet film in the section P ⁱ of the width of the moving strip receives a dose D _c ⁱ of UV radiation in the UV ⁱ UV radiation module,

• if D _c ⁱ exceeds D _max , the corrected length L _c ⁱ between the ^UV module and the electron beam curing device is calculated according to equation 3 ⁱ :

L _c ⁱ = f ₂ (L ⁱ , G ⁱ , G _s ) ... (3 ⁱ )

- the adjustment step includes adjusting the length between the UV ⁱ UV radiation module and the electron beam curing device in such a way that a gloss with a value of G _s is obtained on the organic coating in a section of width P ⁱ downstream of the electron beam curing device.

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

- a module for setting a given value of the gloss G _s of the organic coating, a given range R _s of the gloss of the organic coating and a proportionality constant K of a given linear mathematical relationship between the temperature of the wet film before ultraviolet curing and the gloss of the organic coating after electron beam curing,

- a data collection module for collecting data on the measurement of the temperature T of the wet film at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, as well as data on the measurement of the gloss G of the organic coating in said at least section of the width downstream of the electron beam curing device,

- a correction module for correcting the deviation of the measured gloss G outside the specified gloss range _Rs , wherein the correction includes calculating the corrected temperature _Tc that the wet film must reach in at least said width section downstream of the infrared heater and upstream of the ultraviolet curing device, according to equation 1:

T _s = T + K (G - G _s ) ... (1)

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

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

Fig. 1, which is a schematic representation of a line for applying coating to rolled metal;

Fig. 2 is a block diagram of the sequence of execution of the first embodiment of the method according to the invention;

Fig. 3 is a block diagram of the sequence of execution of the second embodiment of the method according to the invention;

Fig. 4 is a block diagram of the sequence of execution of the third embodiment of the method according to the invention;

Fig. 5 is a block diagram of the sequence of execution of the fourth embodiment of the method according to the invention.

It should be noted that relative spatial location terms such as "upstream", "downstream", "lower", "upper", "above", "below", "before", "after" ... in this application refer to the positions and orientations of the various components of the coil coating line.

The method according to the invention is intended for strips, for example metal strips. Steel, carbon or stainless steel, aluminum, copper are examples of materials of said metal strips. In particular, steel strips can be uncoated or coated with a metal coating on one or both sides of the strip. Examples of possible metallic coated steels are hot-dip galvanized steel, steels coated with a zinc alloy containing 5% by weight of aluminum (Galfan®), steels coated with a zinc alloy containing 55% by weight of aluminum, about 1.5% by weight of silicon, the remainder consisting of zinc and unavoidable impurities from processing (Aluzinc®, Galvalume®), steels coated with an aluminum alloy containing 8 to 11% by weight of silicon and 2 to 4% by weight of iron, the remainder consisting of aluminum and unavoidable impurities from processing (Alusi®), steels coated with a layer of aluminum (Alupur®), steels coated with a zinc alloy containing 0.5 to 20% of aluminum, 0.5 to 10% of magnesium, the remainder consisting of zinc and unavoidable impurities from processing, steels coated with an alloy containing aluminum, magnesium, silicon, possible additional elements, the rest consists of zinc and inevitable impurities resulting from processing.

The method according to the invention is also intended for radiation-curable paints. The term "radiation-curable paints" refers to radiation-curable compositions that are "cured" or dried using short-wave ultraviolet (UV) light or high-energy electrons from electron beam (EB) sources. They typically contain liquid monomers and oligomers in which pigments, fillers, additives, photoinitiators can be dispersed, generally without the need for solvent or water. Thus, they are essentially solvent-free.

As shown in Fig. 1, the coil coating line 1 according to the invention mainly comprises, in series along the path P of the moving belt, a paint application device 2, a heating device 3 containing an infrared heater, a device 4 for ultraviolet curing and a device 5 for electron beam curing.

Path P is the path along which the strip S runs from the entrance to the coil coating line to its exit. It has a width and a length. Along this path, units of equipment are positioned to perform operations on the strip.

The paint application device 2 is a device that allows a wet paint film to be applied to one or both sides of a strip with a given paint thickness. In particular, its purpose is to apply a wet film of radiation-curable paint. In the context of the invention, the paint application technology is not limited.

According to an embodiment of the invention, the paint application device 2 is a roller paint application device. This is an automated machine that coats one or both sides of the strip with rotating rollers. It is designed in such a way that the strip passes through the machine that applies a layer of paint to one or both sides of the strip. There are many designs of roller paint application devices depending on the configuration of the coil coating line, the types of paints used and the types of strips to be coated. A person skilled in the art knows which design is best suited for each case. Generally speaking, a roller paint application device consists of a paint pan, a steel or ceramic pick-up roller and a rubber-coated coating roller. The purpose of the paint pan is to contain, pump and, preferably, heat the paint. The pick-up roller can be partially immersed in the paint and can rotate clockwise or counterclockwise to pick up the paint and transfer it to the coating roller. The latter transfers the paint onto the strip.

According to another embodiment of the invention, the paint application device 2 is a device for applying a curtain coating. In this case, a curtain of paint is applied to a horizontal strip, usually transverse to the curtain. The paint falls from a height under the action of gravity from a hanging matrix or cascade, while the strip is supported by a support roller. This method allows high line speeds and multilayer coatings to be achieved.

Examples of other paint applicators include knife coaters, dip coaters, meniscus coaters, slot coaters, metering rod coaters, and sliding coaters.

The paint is usually applied by a paint applicator over the entire width of the strip. By default, the width of the wet paint film and therefore the organic coating is equal to the width of the strip.

The paint application device 2 is preferably equipped with at least one paint heating device suitable for heating and maintaining the paint at a given temperature. Heating the paint facilitates its application. This also further simplifies the gloss control, since it minimizes the energy consumption of the process at the level of the infrared heater and thus minimizes the inertia of the infrared heater. In the case of a paint application device using a roller, the paint heating device may be a tray heater, i.e. a heater positioned in or around the paint tray. This may also be a temperature-controlled roller, in particular a temperature-controlled pick-up roller, possibly in combination with a tray heater. In the case of a curtain coating device, the paint heating device may be a heater positioned upstream of the hanging die. This may also be a temperature-controlled support roller, possibly in combination with a heater.

The paint application device 2 is preferably equipped with a temperature measuring device for measuring the paint temperature and/or the wet film temperature at the level of the paint application device. The temperature measuring device may be, for example, a temperature sensor, a pyrometer, a thermal imaging camera.

The coil coating line 1 further comprises a heating device 3 comprising an infrared heater positioned along the path P of the moving belt downstream of the paint application device 2 and upstream of the ultraviolet (UV) curing device 4. Its purpose is to heat the wet film of radiation-curable paint. The heating device further improves the control of the temperature of the wet film of paint before its curing in the UV curing device. Since the temperature of the strip leaving the paint application device decreases at a rate that depends on a number of parameters (strip nature, strip width, strip thickness, line speed, etc.), the temperature of the wet film entering the UV curing device may vary significantly from case to case, which may have a negative effect on the gloss. Thanks to the infrared radiation, which directly heats the wet film, the temperature of the wet film can be adjusted very quickly.

According to one variant, the infrared heater covers the entire width of the path P of the moving strip. In this case, the wet film is heated uniformly across its width as it passes (through) the infrared heater.

According to another embodiment, the heating device 3 comprises a plurality of infrared heaters distributed along the width of the path P. In other words, the plurality of infrared heaters form a row substantially parallel to the width of the path P, i.e. perpendicular to the direction of movement of the strip. For the sake of clarity, the infrared heaters described here are independent of each other and are positioned next to each other, but they may be physically inseparable from each other. They may represent individually controllable parts of a single heating device.

With this design, the temperature variations of the strip width can be corrected and minimized. It is preferable that the change in the temperature of the wet film across the strip width at the outlet of the heating device is less than 1°C. This improves the uniformity of the coating gloss across the strip width.

According to another variant, the heating device 3 comprises a base heater sequentially along the strip movement path, covering the entire width of the path P, and a plurality of infrared heaters described above. The base heater can be an infrared heater or an inductor. Due to this design, part of the energy required to achieve the correct temperature of the wet film at the outlet of the heating device is provided by the base heater. Each infrared heater of the plurality of infrared heaters independently provides the remaining part of the energy and can regulate it as required.

The heating device 3 is preferably positioned above the path P, whereby the wet film applied to the upper side of the strip is heated directly. The heating device can also be positioned above and below the path P in order to minimize temperature gradients.

The coil coating line 1 additionally includes an ultraviolet (UV) curing device 4. The purpose of this equipment is to cure the surface of the wet film of the radiation-curable paint. It has been observed that such surface curing creates a very fine texture on the surface of the film, which, in combination with the binding agents and possible other fillers, is one of the causal factors of the gloss of the organic coating after the wet film has been completely cured by the electron beam.

According to one embodiment, the UV curing device 4 covers the entire width of the path P of the moving strip. In this case, the surface of the wet film is cured uniformly across the width of the strip under the influence of UV radiation.

According to another embodiment, the UV curing device 4 comprises a plurality of UV radiation modules distributed over the width of the path P. In other words, the plurality of UV radiation 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 the sake of clarity, the UV radiation modules described herein are independent of each other and are positioned next to each other, but they may be physically inseparable from each other. They may be individually controllable parts of a single UV curing device.

This design allows different widths of track/lane to be exposed to different doses of UV radiation. This helps to correct and minimize gloss variations across the lane width.

UVA and UVB are preferred. UVA is long-wave UV radiation with a wavelength of 320 to 400 nm. UVB is short-wave UV radiation with a wavelength of 280 to 320 nm. These types of radiation can be produced with traditional UV arc lamps.

The UV curing device 4 can preferably move along the path P of the moving belt. This allows the length between the UV curing device and the electron beam curing device to be adjusted, i.e. lengthened or shortened. Indeed, it has been observed that wrinkles or surface roughness that have arisen during UV curing further develop during the time interval between UV curing and electron beam curing, which has an effect on the gloss of the organic coating.

In the case of a plurality of UV radiation modules, each UV radiation module can preferably move along the path P independently of the others.

The coil coating line 1 additionally includes an electron beam curing device 5. The purpose of this equipment is to cure the wet film of radiation-curable paint, i.e. over its entire thickness. It additionally 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 electron beam curing. The electron beam curing device typically operates under the following conditions: 100-200 kV, 20-50 kilogray (kGy), nitrogen inertization at an O ₂ concentration below 200 ppm.

The coil coating line 1 additionally includes a wet film temperature measuring device 6, 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. It can measure the temperature of the wet film over the entire width of the path P of the moving strip or only over a part of the width. Examples of devices for measuring the temperature of the wet film are a pyrometer, a thermal imaging camera, a thermocouple. The measured temperature can be expressed in °C, °F or K.

In the case where the wet film temperature measuring device measures the temperature only in a width section, the measurement in this section can be considered sufficiently representative for gloss control of the entire width of the strip.

Alternatively, a plurality of wet film temperature measuring devices are positioned downstream of the heating device 3 and upstream of the UV curing device in such a way that the entire width of the path P of the moving strip is covered. They form a row substantially parallel to the width of the path P. Accordingly, the heating device preferably comprises a plurality of infrared heaters forming a row substantially parallel to the width of the path P, each infrared heater being intended to heat a section of the width of the strip, the temperature of which is then measured by one wet film temperature measuring device.

In order to further improve the control of the wet film temperature in the UV curing device, the wet film temperature measuring device 6 and the UV curing device 4 are separated by a distance exceeding 2 meters, preferably not more than 1 meter, or the wet film temperature is measured not more than 4 seconds before the curing of the wet film in the UV curing device, preferably not more than 2 seconds. Alternatively or in addition, the section of the path P of the moving strip between the wet film temperature measuring device and the UV curing device can be thermally insulated in order to maintain the measured temperature of the wet film until it is cured in the UV curing device.

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 electron beam curing. It can measure the gloss of the organic coating along the entire width of the path P of the moving strip, or can measure the gloss only on a part of the width. Examples of gloss measuring devices are gloss measuring devices. The measured gloss is preferably expressed in GU (gloss units). The gloss is preferably measured in accordance with the standards ISO 2813:2014 and EN 13523-2:2021. Preferably, the gloss is measured with a 20° geometry, a 60° geometry or an 85° geometry, i.e. the reflection angle is 20°, 60° or 85°. More preferably, the gloss is measured using a 60° geometry.

In the case where the gloss measuring device measures gloss only in a width section, the measurement in this section can be considered sufficiently representative for gloss control over the entire width of the strip.

Alternatively, a plurality of gloss measuring devices are positioned downstream of the electron beam curing device in such a way that the entire width of the path P of the moving strip is covered. They form a row substantially parallel to the width of the path P. Accordingly, the heating device preferably comprises a plurality of infrared heaters forming a row substantially parallel to the width of the path P, each infrared heater being intended to heat a section of the width of the strip, the gloss of which is then measured by one gloss measuring device.

The coil coating line 1 is preferably equipped with a strip speed measuring device, more preferably positioned at the level of the guide roller. An example of a strip speed measuring device is a tachometer built into the roller axis.

The coil coating line 1 may further comprise an inductor 8 upstream of the paint application device 2. It may heat the strip before it reaches the paint application device. The presence of a warm strip in the paint application device facilitates the application of paint. In addition, the temperature reached by the strip in the inductor may be adjusted to correct possible deviations in gloss, as will be described in detail later.

The coil coating line 1 may additionally comprise an input section with an uncoiler 9 for uncoiling the strip to be coated on the line. The uncoiler may be combined with a welding machine or a stapler so that the front end of the strip to be coated can be attached to the rear end of the previous strip.

Alternatively, the coil coating line can be connected to the electroplating line, whereby the strip coated with metal alloys, located in the bath of the electroplating line, is sent already coated with an organic coating without the need to first wind it up and then unwind it.

The coil coating line 1 may further comprise an input accumulator 10 located at the input section of the line downstream of the uncoiler, if required. The accumulator is a piece of equipment that "accumulates" a certain amount of strip. It is a set of upper and lower roller accumulators through which the metal strip is threaded in a serpentine manner, and it stores lengths of metal when two roller accumulators are moved apart. The total length of metal stored depends on the design speed of the line, typically 60 seconds of steady-state metal processing time. When the input section of the coil coating line stops, the rollers move towards each other, and the metal stored in the accumulator continues to feed the rest of the coil coating line.

The coil coating line 1 may further comprise a cleaning section 11 positioned downstream of the input section, in particular downstream of the input accumulator, if applicable. In this section, the strip undergoes a surface preparation step. This type of preparation includes at least one step selected from the following types of treatment: washing, degreasing and conversion treatment. The purpose of washing is to remove loose dirt particles, possible residues of conversion solutions and soap that may have formed on the strip, as well as to achieve a clean and reactive surface. The purpose of degreasing is to clean the surface by removing all traces of organic contaminants, metal particles and dust from the surface. Preferably, degreasing is performed in an alkaline environment. Conversion treatment includes applying a conversion solution to the strip, which chemically reacts with the surface and thereby allows the formation of a conversion layer. The latter increases paint adhesion and corrosion resistance. Conversion treatment preferably uses an acid solution that does not contain chromium. More preferably, the conversion treatment is based on the use of hexafluorotitanic acid or hexafluorozirconic acid.

The coil coating line 1 may further comprise a primer section upstream of the roller coating device 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 application device and curing equipment. Depending on the nature of the primer, the curing equipment may be an oven, such as a convection oven, an infrared (or near infrared) oven or an induction oven, a UV curing device and/or an electron beam curing device.

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

The coil coating line 1 may further comprise a device 13 for rewinding the strip that has been coated on the line into a roll. The rewinding device may be combined with a cutting device to separate the strip from the next strip processed on the line.

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

The gloss control tool comprises a setting module for setting a specified organic coating gloss value G _s , a specified organic coating gloss range R _s , and a proportionality constant K of a preset linear mathematical relationship between the wet film temperature before ultraviolet curing and the organic coating gloss after electron beam curing.

The gloss control tool further comprises a data collection module configured to collect data for measuring the temperature T of the wet film, at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, and also for collecting data for measuring the gloss G of the organic coating, at least in a section of the width downstream of the electron beam curing device.

The gloss control tool further comprises a correction module configured to correct the deviation of the measured gloss G beyond a specified gloss range _Rs , wherein the correction includes calculating a corrected temperature _Tc that the wet film must reach, at least in the width section downstream of the infrared heater and upstream of the ultraviolet curing device according to equation 1:

T _s = T + K (G - G _s ) ... (1)

The gloss control instrument may include a data processing unit formed, for example, by a memory and a processor connected to the memory. The electronic control and measuring device may also include a display screen and input/output means, such as a keyboard and a mouse-type coordinate manipulator, each of which is connected to the data processing unit. Each module from the installation module, the data collection module and the adjustment module may be implemented as software executed by the processor.

The coil coating line is preferably equipped with a gloss control device to facilitate gloss control in the coil coating line.

From a technological point of view, the gloss control of the organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip of coil coating described above is primarily based on the discovery that the wet film temperature before UV curing is a key point. In particular, the inventors found that in dual curing for coil coating, there is a linear relationship between the wet film temperature before UV curing and the gloss of the organic coating after electron beam curing. Therefore, any deviation in gloss after electron beam curing can be effectively and reproducibly corrected by adjusting the wet film temperature before UV curing.

The method is applied on a moving strip. The strip may be a single roll which is unwound at the entrance to the coil coating line. More generally, the strip consists of various rolls attached to each other at their ends. The rolls form essentially one continuous strip, the features and technical characteristics of which, achieved at the exit from the coil coating line, change over time. The strip moves along the path P of the coil coating line in such a way that a wet film of radiation-curable paint, preferably heated and twice cured, is applied. In particular, the strip moves along the path P of the coil coating line in such a way that a wet film of radiation-curable paint is first applied to the strip by means of a paint applicator, then heated by an infrared heater, and then exposed to UV radiation in an ultraviolet curing device, and the final curing occurs in an electron beam curing device. Optionally, the strip can be preheated by means of an inductor 8 positioned upstream of the paint application device 2. Optionally, the paint cured by radiation exposure can be heated in the paint application device.

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

The first step in the 100 method of gloss control is to set some target values necessary for proper control.

First, the target value G _s for the gloss of the organic coating is set. This value corresponds to the gloss requested by the customer or the operator of the coil coating line. From a practical point of view, it can be entered manually in the gloss control tool, in particular in the setup module. Alternatively, it can be automatically retrieved from the order book of the coil coating line, in particular from the planning tool.

Since small deviations in gloss along the strip length are generally acceptable from a quality point of view, a target gloss range R _s of the organic coating is also defined. It can be entered as a range as such, with a minimum and maximum gloss value, or it can be entered as a standard deviation of the target gloss value G _s . Of course, if for some reason small deviations are to be avoided, the target gloss value G _s can be entered as a minimum gloss and the maximum gloss or standard deviation can be set to zero. From a practical point of view, the target gloss range R _s can be entered manually in the gloss control tool, in particular in the setup module. Alternatively, it can be automatically obtained from the coil coating line control tool or from the coil coating line order book, in particular from the planning tool. The target gloss range R _s can also be obtained from standards such as EN10169:2013.

In addition, since gloss control is based on a linear mathematical relationship between the wet film temperature before UV curing and the gloss of the organic coating after electron beam curing, it is necessary to establish a constant K proportionality to this linear mathematical relationship so that the control is performed correctly.

The proportionality constant K can be obtained in a calibration step performed before the adjustment step. During this calibration step, wet films of radiation-curable paint to be used in a coil coating line are heated at different temperatures, cured by a dual-curing process under standard curing conditions, and then the gloss of the organic coatings is measured. In this way, the proportionality constant K can be derived. Preferably, it is expressed in units of °C/GU, °F/GU or K/GU, depending on the unit of measurement of the temperature. This calibration step can be performed once and for all, and it is not necessary to perform it every time the method according to the invention is implemented.

From a practical point of view, the proportionality constant K is obtained from a predetermined linear mathematical relationship between the wet film temperature before UV curing and the gloss of the organic coating after electron beam curing, wherein the predetermined linear mathematical relationship is available to the operator of the coil coating line. By "predetermined" it is meant that a calibration step, preferably as described above, has been carried out before the implementation of the method on the coil coating line. The proportionality constant K can be entered manually in the gloss control tool, in particular in the setup module. Alternatively, it can be obtained automatically by intersecting the predetermined linear mathematical relationships entered in the gloss control tool, possibly in the form of a table, with a reference to the paint from the order book of the coil coating line, in particular from the planning tool.

For example, it has been observed that for radiation curing paints commercially available for coating steel coils, the K constant is typically in the range of 0.3 to 1.2.

In the second step 120 of the gloss control method, the results of measuring the temperature T of the wet film are collected, at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, and the results of measuring the gloss G of the organic coating are collected, at least in a section of the width downstream of the electron beam curing device.

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

Preferably, both measurements are performed at sufficiently short intervals to ensure proper gloss control. Examples of time intervals are: less than 30 s, less than 20 s, less than every 10 s, less than every 5 s, less than every 2 s, less than every second. More preferably, both measurements are continuous or substantially continuous. Preferably, both measurements are collected at sufficiently short intervals to ensure proper gloss control. 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, both measurements are collected continuously or substantially continuously. Preferably, the measurements are collected in the gloss control instrument, in particular in the data acquisition module, more preferably automatically using an appropriate interface.

By "a section of width" it is meant that the moving strip is conceptually divided into parts adjacent to each other along the width of the strip. This may be one section along the width or multiple sections. Therefore, the wet film and the organic coating may also be conceptually divided into sections of the same width. By the expression "at least a section of width" it is meant that the method is implemented either on one section of width, or on multiple sections of width, or on the entire width of the moving strip. In the event that this is not implemented across the entire width, it is thus possible to measure and collect:

- the temperature T of the wet film over one section of the width, if the measurement over this section of the width is considered sufficiently representative of the average temperature over the entire width of the strip, or,

- wet film temperatures over multiple width sections, so that the temperature over each width section can be controlled independently of other sections.

Similarly, it is possible to measure and collect:

- the gloss G of the organic coating in one section of the width, if the measurement in this section of the width is considered sufficiently characteristic to control the gloss over the entire width of the strip, or,

- gloss values of the organic coating in a plurality of width regions, whereby the gloss in each width region can be controlled independently of the other regions. Details on how to control the gloss in this case are presented later with reference to Fig. 5.

In one embodiment, the collection step is performed after the installation step.

In another embodiment, in particular during continuous operation of the coil coating line, the data acquisition step can be performed in parallel with the setup step. In such a case of continuous operation, since the strip consists of different rolls attached to each other at their ends, changes in the strip features and the strip technical characteristics often occur. While the data acquisition step is performed, any of the set parameters, in particular any value from the specified gloss value G _s , the specified gloss range R _s and/or the constant K, may have to be changed for some reason, such as a change in the specified gloss or a change in the paint cured by exposure to radiation. Therefore, the setup step is performed.

In the third step 130 of the gloss control method, a possible deviation of the measured gloss G outside the specified gloss range R _s is corrected. First, a possible deviation of the gloss is estimated by comparing the measured gloss G with the specified gloss value G _s and/or with the specified gloss range R _s . If the measured gloss G is still within the specified gloss range R _s , the settings are saved. If the measured gloss G deviates from the specified gloss range R _s , then the corrected temperature T _c , which must be reached by the wet film, at least in the section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, is calculated according to equation 1:

T _s = T + K (G - G _s ) ... (1)

The evaluation of the gloss deviation may be performed at any time. Preferably, it may be performed at sufficiently short intervals to ensure proper gloss control. Examples of time intervals are: less than 30 s, less than 20 s, less than every 10 s, less than every 5 s, less than every 2 s, less than every second. More preferably, the evaluation is continuous or substantially continuous.

After the corrected temperature has been calculated, the calculation result, i.e. the corrected temperature T _c , is preferably made available to the line operator. The latter can make the necessary adjustments.

Generally speaking, the line setting is adjusted taking into account the calculated corrected temperature T _c , as a result of which a gloss with a value of G _s is obtained on the organic coating, at least in a portion of the width of the moving strip downstream of the electron beam curing device. In particular, the line setting is adjusted so that the wet film reaches the corrected temperature T _c , at least in a portion of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device.

In the first embodiment illustrated in Fig. 2, after calculating the corrected temperature, the power of the infrared heater is adjusted so that the wet film reaches the corrected temperature T _c , at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device. Adjusting the power of the infrared heater includes turning the infrared heater on or off. By adjusting the infrared heater, the temperature of the wet film is adjusted in a section of the width downstream of the infrared heater and upstream of the ultraviolet curing device, and a gloss with a value of G _s downstream of the electron beam curing device is obtained on the organic coating in the section of the width. Adjusting the power of the infrared heater can be performed either manually by the operator or automatically using a gloss control tool, in particular a correction module.

Alternatively, in the case where the coil coating line is equipped with an inductor upstream of the paint applicator, after calculating the corrected temperature, the power of the inductor is adjusted so that the strip temperature is at the temperature level of the paint applicator, which is adjusted so that the wet film reaches the corrected temperature T _c at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device. This alternative method of gloss adjustment is particularly useful in the case where the infrared heater is already operating at maximum power and the wet film temperature upstream of the ultraviolet curing device needs to be increased further. Due to the additional heating of the strip in the inductor, the overheating created by the infrared heater is reduced.

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

In another embodiment, in particular during continuous operation of the coil coating line, the adjustment step can be carried out in parallel with the collection step. In the case of continuous operation, since the strip consists of different rolls attached to each other at the ends, changes in the strip features and technical characteristics of the strip often occur. These can lead to changes in gloss. While the collection step is in progress, the adjustment step is carried out to adjust the measured gloss.

Optionally, the method further comprises a step 110, during which the initial conditions of the line are set. This step is called the initial line setup step. As explained above, the method is carried out in such a way that any deviation of the measured gloss outside the specified gloss range R _s is corrected. However, at the beginning of a production campaign on a coil coating line or after an important change, for example, of the strip format, paint thickness, paint color or line speed, the line conditions may be offset from the line conditions suitable for achieving the specified gloss value G _s . In such a case, the infrared heater may not heat up properly and/or it may take some time to reach the power corresponding to the corrected temperature T _c . Consequently, a portion of the coated strip may have to be disposed of, since the gloss does not meet the specifications. In addition, the UV dose to which the wet film must be exposed in order to cause a surface roughness that will lead to the specified gloss value may be inappropriate. In this case, the infrared heater needs to compensate for the UV dose shift, possibly by heating up more, which takes time. And here, part of the coated strip may have to be rejected because the gloss is not within specification. In order to minimize the length of the coated strip that is outside specification, it is preferable to set the initial conditions of the line.

In order to achieve this, a plurality of process parameters and/or technical characteristics of the coated strip are collected in a first sub-step. An example of a process parameter is the initial line speed LS ₀ . It is preferable to use the parameter that is recommended for coating the next roll on the coil coating line. Another example is the initial thickness FTh ₀ of the wet film applied to the strip by the paint applicator. The initial film thickness is preferably a thickness that corresponds to the thickness of the organic coating determined for the next roll to be coated on the coil coating line. Another example is the temperature of the moving strip in front of the paint applicator, preferably in front of the inductor. Examples of technical characteristics are the initial strip thickness STh ₀ , the initial strip width SWd ₀ , the paint color. Preferably, the initial line speed LS ₀ , the initial thickness FTh ₀ , the initial strip thickness STh ₀ , the initial strip width SWd _{0 ,} and the paint color are collected. From a practical point of view, the process parameters and/or technical data can be entered manually in the gloss control tool, in particular in the setup module. Alternatively, they can be automatically retrieved from the order book of the coil coating line, in particular from the planning tool, and/or derived from the order book. For example, the initial film thickness FTh ₀ can be derived from the organic coating thickness specified in the order book.

Once the process parameters and/or specifications have been collected, the second sub-step is to set the initial line conditions, taking into account the collected process parameters and/or specifications. In particular, they are calculated based on the collected process parameters and/or specifications. The following initial line conditions can be set:

- initial power PW ₀ of the infrared heater,

- the initial dose D ₀ of UV radiation from the UV curing device or UV module, if applicable,

- the initial length L ₀ between the UV curing device or UV module, if applicable, and the electron beam curing device.

The initial power PW ₀ can be set if the mass flow rate of the moving strip, the specific heat capacity of the strip and the infrared radiation output are known. The initial dose D ₀ of UV radiation can be set based on the data obtained in the calibration step performed before the initial line setup step. The initial length L ₀ can be set based on the data obtained in the calibration step performed before the initial line setup step.

From a practical point of view, the initial line conditions can be manually entered into the coil coating line control tool. Alternatively, they can be automatically inserted using the gloss control tool in the coil coating line control tool.

In one embodiment, the initial line setup step 110 is performed before the setup step 100. This helps to start production with line conditions that are already optimized for the first roll of the production campaign, in addition to the initial combination of the gloss target value G _s , the gloss target range R _s and the constant K. During production, a collection step and an adjustment step can be performed to control the gloss. When any of the specified parameters, in particular any parameter from the gloss target value G _s , the gloss target range R _s and/or the constant K, needs to be changed for any reason, such as when a specific gloss target changes or when the degree of cure of the radiation-curable paint changes, then based on the data collection step 120 and the adjustment step 130 it is necessary to maintain the measured gloss within the gloss target range R _s .

In another embodiment, the initial line setup step 110 is performed after the setup step 100, as illustrated in Fig. 2. In this way, the initial line conditions can be adjusted taking into account the specified gloss value G _s . In this way, the line conditions are better optimized for the first roll of a production campaign. In addition, during production, when any of the specified parameters, in particular any parameter from the specified gloss value G _s , the specified gloss range R _s , and/or the constant K, need to be changed for any reason, the initial line settings can be reset to help minimize the transition period.

In another embodiment, the initial line setup step 110 is performed before and after the installation step 100 to take advantage of the benefits of both options described above.

In another embodiment, particularly during continuous operation of the coil coating line, the initial setup stage of the line can be carried out in parallel with the collection stage. In such a case of continuous operation, since the strip consists of different rolls attached to each other at their ends, changes in the strip characteristics and the technical characteristics of the strip often occur. Re-initialization of the line conditions when one of these changes occurs helps to achieve the specified gloss value as quickly as possible.

The second embodiment of the method will now be described with reference to Fig. 3.

This embodiment differs mainly from the first in that the adjustment step contains additional sub-steps in order to:

- ensure that the calculated corrected temperature T _c does not exceed the maximum temperature T _max , which could lead to deterioration in the quality of the radiation-cured paint, and,

- adjust the deviation of the measured gloss G accordingly.

Due to this configuration, the method additionally prevents thermal degradation of the wet film when heated in an infrared heater.

The details provided in the description of the first embodiment of the invention are also applicable to the second embodiment. Additional steps and corresponding features are described in detail below.

The setting step 100 further comprises setting the maximum temperature T _max for the radiation-cured paint. This temperature may be the one recommended by the paint supplier. Alternatively, this temperature may be identified by the operator of the coil coating line, in particular by measuring the monomer emissions of the paint as a function of temperature, this measurement being carried out offline or possibly online at the level of the infrared heater. From a practical point of view, the maximum temperature T _max may be entered manually in the gloss control tool, in particular in the setting module. Alternatively, the temperature value may be obtained automatically by intersecting the various maximum temperatures entered in the gloss control tool with reference to the paint from the order book of the coil coating line, in particular from the planning tool.

The data collection step 120 further includes collecting data on the UV dose D of the UV module. The power of the UV module is usually known from the operator, possibly from the control instrument of the coil coating line, but for a given power, the actual UV dose to which the wet film is exposed varies depending on the line speed LS. Accordingly, the UV dose is calculated based on the power of the UV module and the line speed and the resulting data is collected. The line speed itself is usually known from the operator, possibly from the control instrument of the coil coating line.

Preferably, the UV dose is recalculated and the resulting data is collected each time the UV module power and/or the line speed is adjusted. More preferably, the UV dose data collection is substantially continuous. Preferably, the UV dose data is collected in the gloss control instrument, in particular in the data collection module, more preferably automatically by means of an appropriate interface.

In the correction step 130, once the corrected temperature T _c has been calculated, it is compared with the maximum temperature T _max . If T _c is lower than T _max , the power of the infrared heater is adjusted so that the wet film reaches the corrected temperature T _c at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, as in the first embodiment of the invention. Alternatively, in the case where the coil coating line is equipped with an inductor upstream of the paint applicator, once the corrected temperature has been calculated, the power of the inductor is adjusted so that the strip temperature is at the level of the paint applicator, and is also adjusted so that the wet film reaches the corrected temperature T _c at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device.

If T _c exceeds T _max , the gloss must be adjusted without further increasing the power of the infrared heater or the power of the inductor. One way to do this is to adjust the power of the UV module. Indeed, it has been observed that this has an effect on the gloss of the organic coating. The more the UV dose on the wet film increases, the more the gloss decreases. Therefore, the adjustment step 130 further comprises calculating the adjusted UV dose D _c to which the wet film must be exposed, at least in a portion of the width of the moving strip in the UV module, according to equation 2:

D _c = f ₁ (D, G, G _s ) ... (2)

Equation (2) can be obtained in a calibration step performed before the adjustment step, preferably before the setting step. In this calibration step, wet films of radiation-curable paint to be used in a coil coating line are exposed to different doses of UV radiation, cured by electron beam curing under standard curing conditions, and then the gloss of the organic coating is measured. In this way, the function f ₁ can be derived for each radiation-curable paint. This calibration step can be performed once and for all, and it is not necessary to perform it every time the method according to the invention is implemented.

Preferably, during the setup step, a function f ₁ of a predetermined mathematical relationship between the UV dose received by the wet film of the radiation-curable paint and the gloss of the organic coating after electron beam curing is specified. By "predetermined" is meant that a calibration step, preferably as described above, has been carried out before the implementation of the method on the coil coating line. The function f ₁ can be entered manually in the gloss control tool, in particular in the setup module. Alternatively, it can be obtained automatically by intersecting the predetermined mathematical relationships entered in the gloss control tool with a reference to the paint from the order book of the coil coating line, in particular from the planning tool.

For example, it has been observed that for radiation curable paints and those commercially available for coating steel coils, the f ₁ function is typically associated with a gloss curve that decreases towards an asymptote as the UV dose increases.

After calculating the corrected UV dose, the calculation result, i.e. the corrected UV dose D _c , is preferably made available to the line operator. The latter can make the necessary adjustments.

Generally speaking, the line setting, other than the infrared heater power setting and the inductor power, if applicable, is adjusted taking into account the calculated corrected UV dose D _c , resulting in a gloss of G _s value being produced on the organic coating, at least over a portion of the width of the moving strip downstream of the electron beam curing device.

In the embodiment illustrated in Fig. 3, after the corrected UV dose has been calculated, the power of the UV module is adjusted so that the wet film, at least in a section of the width of the moving strip, is exposed to a dose D _c of UV radiation in the UV module. By adjusting the UV module, the UV dose acting on the wet film in a section of the width of the UV module is adjusted, and a gloss with a value G _s is achieved on the organic coating in a section of the width downstream of the electron beam curing device. The adjustment of the power of the UV module can be carried out either manually by the operator or automatically by means of a gloss control tool.

The third embodiment of the method will now be described with reference to Fig. 4.

This embodiment differs mainly from the second embodiment in that the adjustment step contains additional sub-steps in order to:

- ensure that the calculated adjusted UV dose D _c does not exceed the maximum UV dose D _max to which the wet film may be exposed,

- adjust the deviation of the measured gloss G accordingly.

Due to this configuration, the method additionally prevents excessive curing of the wet film in the UV curing device, which can negatively affect the gloss.

The details provided in the description of the first and second embodiments of the invention are also applicable to the third embodiment. Additional steps and corresponding features are described in detail below.

In this embodiment, the UV module of the ultraviolet curing device of the coil coating line can move along the path P. Accordingly, the length L between the UV module and the electron beam curing device can be adjusted.

The setting step 100 further comprises setting the maximum UV dose D _max that the wet film can receive in the UV module. This UV dose can be the dose recommended by the paint supplier. Alternatively, it can be identified by the operator of the coil coating line, in particular in the calibration step. From a practical point of view, the maximum UV dose D _max can be entered manually in the gloss control tool, in particular in the setting module. Alternatively, it can be obtained automatically by intersecting the different maximum UV doses entered in the gloss control tool with reference to the paint from the order book of the coil coating line, in particular from the planning tool.

The data collection step 120 includes collecting data on the length L between the UV module and the electron beam curing device. This length is usually known to the operator, possibly known from the control tool of the coil coating line. This value can be collected manually. Preferably, this value is collected in the gloss control tool, more preferably automatically using an appropriate interface. Preferably, it is collected only when the length L changes.

During the adjustment step 130, after the adjusted UV dose D _c has been calculated, it is compared with the maximum UV dose D _max . If D _c is lower than D _max , the power/setting of the UV module is adjusted so that the wet film, at least in a section of the width of the moving strip, is exposed to the UV dose D _c in the UV module. By adjusting the UV module, the UV dose to which the wet film is exposed in a section of the width of the UV module is adjusted, and a gloss with the value G _s is achieved on the organic coating in a section of the width downstream of the electron beam curing device, as in the second embodiment of the invention.

If D _c exceeds D _max , the gloss must be adjusted without further increasing the UV dose of the UV module. One way to do this is to adjust the distance between the UV module and the electron beam curing device. Indeed, it has been observed that this affects the gloss of the organic coating. The longer the time between UV curing and electron beam curing, the lower the gloss. Therefore, the adjustment step 130 further includes calculating the adjusted length L _c between the UV module and the electron beam curing device, according to equation 3:

L _c = f ₂ (L, G, G _s ) ... (3)

Equation (3) can be obtained in a calibration step performed before the adjustment step, preferably before the setting step. In this calibration step, wet films of radiation-curable paint to be used in a coil coating line are successively UV-cured and electron-beam-cured under standard curing conditions with different times between the two curing processes, and then the gloss of the organic coating is measured. In this way, the function f ₂ can be derived for each radiation-curable paint. This calibration step can be performed once and for all, and it is not necessary to perform it every time the method according to the invention is implemented.

Preferably, during the setup step, a function f ₂ of a predetermined mathematical relationship between two values is specified: the distance between the UV module and the electron beam curing device, and the gloss of the organic coating after electron beam curing. By "predetermined" is meant that a calibration step, preferably as described above, was carried out before the implementation of the method on the coil coating line. The function f ₂ can be entered manually in the gloss control tool, in particular in the setup module. Alternatively, it can be obtained automatically by intersecting the predetermined mathematical relationships entered in the gloss control tool with a reference to the paint from the order book of the coil coating line, in particular from the planning tool.

For example, it has been observed that for radiation curable paints commercially available for coating rolled steel products, the f ₂ function is typically associated with a gloss curve that decreases towards an asymptote as L increases.

After calculating the corrected length, the result of the calculation, i.e. the corrected length L _c , is preferably made available to the line operator. The latter can make the necessary adjustments.

Generally speaking, the line setting, other than the setting of the infrared heater power, the inductor power, if applicable, and the UV module power, is adjusted taking into account the calculated corrected length L _c , as a result of which a gloss with a value G _s is obtained on the organic coating, at least in a portion of the width of the moving strip downstream of the electron beam curing device.

In the embodiment illustrated in Fig. 4, after the corrected length has been calculated, the distance between the UV radiation module and the electron beam curing device is adjusted so that a gloss with a value of G _s is obtained on the organic coating over at least a portion of the width of the moving strip downstream of the electron beam curing device. The adjustment of the length can be performed either manually by the operator or automatically by means of a gloss control tool.

Alternatively, especially if the distance between the UV module and the electron beam curing device cannot be further increased or shortened, the line speed can be adjusted. In this case, the initial line adjustment is performed again to adjust it according to the new line speed, the initial power PW ₀ of the infrared heater, the initial UV dose D ₀ of the UV curing device and the initial length L ₀ between the UV curing device and the electron beam curing device.

A fourth embodiment of the method will now be described with reference to Fig. 5. This embodiment differs mainly from the first, second and third embodiments in that the gloss is controlled at each section of the width of the moving strip independently of the other parts. Thanks to this configuration, it is possible to reduce temperature deviations along the width of the strip, which lead to deviations in gloss along the width, by adjusting the power of each infrared heater of the heating device independently of the other infrared heaters. The details provided in the description of the first, second and third embodiments are applicable to the fourth embodiment. The differences are described in detail below.

To implement the fourth embodiment of the method, the line for applying coating to rolled metal additionally includes (in comparison with the line for applying coating to rolled metal used to implement the first embodiment of the method) a heating device 3 containing a plurality of infrared heaters, designated below as IR, IR', IR''... IR ⁱ , forming a row essentially parallel to the width of the path P.

In this case, the second step 120 includes collecting the results of measuring the temperature of the wet film at a plurality of width sections downstream of the infrared heaters and upstream of the ultraviolet curing device. In this case, each section P, P', P''… P ⁱ of the width of the moving strip downstream of the infrared heaters and upstream of the ultraviolet curing device is assigned one measurement value T, T', T''… T ⁱ at each time t. This assignment can be performed by a plurality of wet film temperature measuring devices. This can also be performed by a single wet film temperature measuring device capable of measuring the temperature of the wet film over its entire width, such as, for example, a thermal imaging camera.

Similarly, the second step includes collecting the results of measurements of the gloss values of the organic coating at a plurality of width sections downstream of the electron beam curing device. In this case, each section P, P', P'' … P ⁱ of the moving strip downstream of the electron beam curing device is assigned at each time t a single measurement value G, G', G'' … G ⁱ . This assignment can be performed by a plurality of gloss measuring devices. It can also be performed by a single gloss measuring device capable of measuring the gloss of the organic coating over its entire width, such as an oscillating gloss meter

In this embodiment of the invention, the step 130 of correcting includes correcting a possible deviation of the measured gloss values outside the specified gloss range R _s in each width section, independently of the others. First, a possible deviation of the gloss values is estimated by comparing the measured gloss values G, G', G'' ... ^Gi with the specified gloss value G _s and/or with the specified gloss range R _s . For any width section P ⁱ , independently of the other sections, if the measured gloss value ^Gi is still within the specified gloss range R _s , the setting of the infrared heater IR ⁱ is maintained. If the measured gloss value ^Gi deviates outside the specified gloss range R _s , the corrected temperature T _c ⁱ , the value of which the wet film must reach in the width section P ⁱ downstream of the infrared heater IR ⁱ and upstream of the ultraviolet curing device, is calculated in accordance with equation 1 ⁱ .

T _c ⁱ = T ⁱ + K (G ⁱ - G _s ) … (1 ⁱ )

For any section P ⁱ of width in the correction step S ^{i ,} after the corrected temperature has been calculated in the calculation substep C ⁱ , the result of the calculation, i.e. the corrected temperature T _c ⁱ , is preferably made available to the line operator. The latter can make the necessary corrections.

In general, the line setting is adjusted based on the calculated corrected temperature T _c ⁱ , resulting in a gloss of value G _s being produced on the organic coating in a region P ⁱ of the moving strip width downstream of the electron beam curing device.

In the first embodiment illustrated in Fig. 5, for any width section P ⁱ , after the corrected temperature calculations have been performed, the line setting is adjusted so that the wet film reaches the corrected temperature T _c ⁱ in the width section P ⁱ of the moving strip downstream of the infrared heater IR ⁱ and upstream of the ultraviolet curing device. In particular, the power of the infrared heater IR ⁱ is adjusted so that the wet film reaches the corrected temperature T _c ⁱ in the width section P ⁱ downstream of the infrared heater IR ⁱ and upstream of the ultraviolet curing device. Consequently, a gloss of value G _s is obtained on the organic coating in the width section P ⁱ downstream of the electron beam curing device.

According to a second variant of this embodiment, the ultraviolet curing device of the coil coating line comprises a plurality of independently controlled UV, UV', UV'' … UV ⁱ UV radiation modules forming a row substantially parallel to the path width P, and the data collection step 120 further includes collecting the UV radiation dose D, D', D'' … D ⁱ of the UV radiation modules.

In this embodiment, for any width section P ⁱ after the corrected temperature T _c ⁱ has been calculated, it is compared with the maximum temperature T _max . If T _c ⁱ is lower than T _max , then the power of the infrared heater IR ⁱ is adjusted so that the wet film reaches the corrected temperature T _c ⁱ in the width section P ⁱ downstream of the infrared heater IR ⁱ and upstream of the ultraviolet curing device, as in the first embodiment.

If T _c i exceeds T _max , and as described in the second embodiment, the adjustment step 130 further includes calculating an adjusted UV radiation dose D _c ⁱ to which the wet film in the moving strip width section P ⁱ in the UV radiation module UV ⁱ is to be exposed, in accordance with equation 2 ⁱ :

D _c ⁱ = f ₁ (D ⁱ , G ⁱ , G _s ) ... (2 ⁱ )

Once the corrected UV dose has been calculated, the result of the calculation, i.e. the corrected UV dose D _c ⁱ , is preferably made available to the line operator. The latter can make the necessary adjustments.

In general, the line setting, other than the setting of the infrared heater power IR ⁱ and the inductor power, if applicable, is adjusted taking into account the calculated corrected UV dose D _c ⁱ , resulting in a gloss of G _s value being obtained on the organic coating in a section P ⁱ of the width of the moving strip downstream of the electron beam curing device.

In this embodiment of the invention, after the corrected UV dose D _c ⁱ has been calculated, the power of the UV module UV ⁱ is adjusted so that the wet film in the section Pi of the width of the moving strip is exposed to the dose D _c ⁱ of UV radiation in the UV module UV ⁱ . Consequently, a gloss with the value G _s is obtained on the organic coating in the section P ⁱ of the width downstream of the electron beam curing device.

According to a third embodiment of the invention and in comparison with the second embodiment, each UV radiation module can move along the path P independently of the others, and the collecting step further includes collecting the length values L, L', L'' … L ⁱ between the UV modules and the electron beam curing device.

In this variant, for any section Pi of width after calculating the adjusted UV dose D _c ⁱ , it is compared with the maximum UV dose D _max . If D _c ⁱ is less than D _max , then the power of the UV ⁱ module is adjusted so that the wet film in the section Pi of width of the moving strip is exposed to the UV dose D _c ⁱ in the UV ⁱ module, as in the second variant.

If D _c ⁱ exceeds D _max , and as described in the third embodiment, the correction step 130 further includes calculating a corrected length L _c ⁱ between the UV irradiation module UV ⁱ and the electron beam curing device, according to equation 3 ⁱ :

L _c ⁱ = f ₂ (L ⁱ , G ⁱ , G _s ) ... (3 ⁱ )

Once the adjusted length has been calculated, the result of the calculation, i.e. the adjusted length L _c ⁱ , is preferably made available to the line operator. The latter can make the necessary adjustments.

In this embodiment of the invention, after the corrected length L _c ⁱ has been calculated, the length between the UV ⁱ UV radiation module and the electron beam curing device is adjusted such that a gloss with a value G _s is obtained on the organic coating in the width section P ⁱ downstream of the electron beam curing device.

Optionally, the initial line setup step 110 differs from the step described in the first embodiment in that, in its second sub-step, the following initial line conditions are set taking into account the process parameters and/or technical characteristics that were collected during the first sub-step:

- initial power PW0, PW0', PW0'' … PW0 ⁱ of infrared heaters IR, IR', IR'' … IR ⁱ ,

- initial dose D0, D0', D0'' … D0 ⁱ of UV radiation of modules UV, UV', UV'' … UV ⁱ of UV radiation,

- initial length L ₀ , L ₀ ', L ₀ '' … L ₀ ⁱ between UV, UV', UV'' … UV ⁱ UV radiation modules and the electron beam curing device.

The invention also relates to a method for forming an organic coating on a moving strip on a line for applying coating to rolled metal, which includes, sequentially along the path P of the moving belt, a device for applying paint, a heating device containing an infrared heater, an ultraviolet curing device and an electron beam curing device, wherein the method includes the steps of:

- application of a wet film of radiation-curable paint to a moving strip using a paint application device,

- heating a wet film of radiation-cured paint in an infrared heater,

- the effect of UV radiation on a wet film of radiation-curable paint in a UV curing device,

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

The gloss of the organic coating is controlled by:

- setting a given value G _s of the gloss of the organic coating, a given range R _s of the gloss in relation to the gloss of the organic coating and a constant K of proportionality of a predetermined linear mathematical relationship between the temperature of the wet film before ultraviolet curing and the gloss of the organic coating after electron beam curing,

- collecting data on the measurement of the temperature T of the wet film, at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, as well as collecting data on the measurement of the gloss G of the organic coating, at least in a section of the width downstream of the electron beam curing device,

- correcting the deviation of the measured gloss G outside the specified gloss range R _s , wherein this correction step includes the sub-step of calculating the corrected temperature T _c , which the wet film must reach, at least in the width section downstream of the infrared heater and upstream of the ultraviolet curing device, according to equation 1:

T _s = T + K (G- G _s ) ... (1)

All the details given regarding the gloss control method and all the details given regarding the coil coating line also apply to the organic coating formation method.

The invention also relates to a method for producing a pre-painted metal, including a metal strip and an organic coating, on a line for applying a coating to a rolled metal product, which includes, sequentially along the path P of the moving metal strip, a device for applying paint, a heating device containing an infrared heater, an ultraviolet curing device and an electron beam curing device, wherein the method includes the following steps:

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

- heating a wet film of radiation-cured paint in an infrared heater,

- exposure of a wet film of radiation-curable paint to UV radiation in a UV curing device,

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

The gloss of the organic coating is controlled by:

- setting a given value G _s of the gloss of the organic coating, a given range R _s of the gloss in relation to the gloss of the organic coating and a constant K of proportionality of a predetermined linear mathematical relationship between the temperature of the wet film before ultraviolet curing and the gloss of the organic coating after electron beam curing,

- collecting data on the measurement of the temperature T of the wet film, at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, as well as collecting data on the measurement of the gloss G of the organic coating, at least in a section of the width downstream of the electron beam curing device,

- correcting the deviation of the measured gloss G outside the specified gloss range R _s , wherein this correction step includes the sub-step of calculating the corrected temperature T _c , which the wet film must reach, at least in the width section downstream of the infrared heater and upstream of the ultraviolet curing device, according to equation 1:

T _s = T + K (G - G _s ) ... (1)

All details given regarding the gloss control method and all details given regarding the coil coating line apply to the pre-painted metal manufacturing method.

Claims (82)

1. A method for controlling the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip on a coil coating line, comprising, sequentially arranged along the path P of the moving strip: a paint application device, a heating device containing an infrared heater, an ultraviolet curing device and an electron beam curing device, comprising the steps of: - set the specified value G _s of the gloss of the organic coating, the specified range R _s of the gloss of the organic coating and the constant K of proportionality of the specified linear mathematical relationship between the temperature of the wet film before ultraviolet curing and the gloss of the organic coating after electron beam curing, wherein the constant K is obtained by preliminary calibration; - collecting the results of measuring the temperature T of the wet film at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, and collecting the results of measuring the gloss G of the organic coating in at least the specified section of the width downstream of the electron beam curing device; - correcting the deviation of the measured gloss G outside the specified gloss range R _s , wherein this correction step includes a sub-step in which the corrected temperature T _c is calculated, which must be achieved for the wet film in at least the specified width section downstream of the infrared heater and upstream of the ultraviolet curing device, according to equation 1 T _s = T + K (G - G _s ) ... (1). 2. The method according to item 1, also comprising a step of initial line setup, in which: - collect a set of process parameters and/or technical characteristics of the strip; - at least one initial condition for the line is established from the following conditions: the initial power PW ₀ of the infrared heater, the initial dose D ₀ of the UV radiation of the ultraviolet curing device and the initial length L ₀ between the ultraviolet curing device and the electron beam curing device, taking into account the specified collected process parameters and/or technical characteristics of the strip. 3. The method according to claim 1 or 2, wherein the adjustment step also comprises adjusting the power of the infrared heater so that the wet film reaches the said adjusted temperature T _c on at least the said portion of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device. 4. The method according to claim 1 or 2, wherein said line for applying coating to rolled metal also comprises an inductor upstream of the paint application device, wherein the correction step also comprises adjusting the power of the inductor so that the wet film reaches the corrected temperature T _c on at least said section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device. 5. The method according to item 1 or 2, wherein: - the ultraviolet curing device contains a UV radiation module; - at the installation stage, the maximum temperature T _max for the specified radiation-curing paint is also set; - at the data collection stage, data on the UV radiation dose D of the UV radiation module are also collected; - the adjustment stage also contains sub-stages, in which: evaluate whether T _c exceeds T _max , if not superior, adjusting the power of the infrared heater so that the wet film reaches the corrected temperature T _c at least over the specified portion of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, if T _c exceeds T _max , determining the corrected UV dose D _c that the wet film over at least the specified width section is to receive in the UV module, taking into account the collected UV dose D data, the measured gloss G and the specified gloss value G _s , based on the preliminary calibration. 6. The method according to claim 5, wherein the adjustment step also comprises adjusting the power of the UV radiation module so that the wet film on at least the specified section of the width of the moving strip is exposed to irradiation until an adjusted dose D _c of UV radiation is obtained. 7. The method according to paragraph 5, wherein: - the UV radiation module is movable along the path P; - at the installation stage, the maximum dose D _max of UV radiation that the wet film can receive in the UV radiation module is also set; - the collection step additionally includes the collection of the length values L between the UV radiation module and the electron beam curing device; - the adjustment stage also includes sub-stages, in which: if T _c exceeds T _max , evaluate whether D _c exceeds the value of D _max , if not superior, adjusting the power of the UV radiation module so that the wet film at least over a section of the width of the moving strip receives a corrected dose D _c of UV radiation, if D _c exceeds D _max , The corrected length L _c between the UV module and the electron beam curing device is determined taking into account the collected values of the length L, the measured gloss G and the specified gloss value G _s , based on the preliminary calibration. 8. The method according to claim 7, wherein the adjustment step also comprises adjusting the length between the UV radiation module and the electron beam curing device to the adjusted length L _c so that a gloss with a value of G _s is obtained on the organic coating on at least the specified section of the width of the moving strip downstream of the electron beam curing device. 9. The method according to item 1, wherein: - the heating device comprises a set of infrared heaters IR, IR', IR'' … IR ⁱ , forming a row essentially parallel to the width of the path P; - at the data collection stage, measurements of the temperatures T, T', T'' … T ^{i of} the wet film are collected in a set of sections P, P', P'' … P ⁱ of the width of the moving strip downstream of the infrared heaters and upstream of the ultraviolet curing device, and measurements of the gloss G, G', G'' … G ⁱ of the organic coating are collected in the specified set of sections P, P', P'' … P ⁱ of the width downstream of the electron beam curing device; - at the correction stage for any section P ⁱ of width, independently of other sections, the deviation of the measured gloss G ⁱ beyond the specified gloss range R _s is corrected, wherein this correction stage S ⁱ includes the sub-stage C ⁱ of calculating the corrected temperature T _c ⁱ , which must be achieved by the wet film in the section P ⁱ of width downstream of the infrared heater IR ⁱ and upstream of the ultraviolet curing device, in accordance with the equation T _c ⁱ = T ⁱ + K (G ⁱ - G _s ) ... (1 ⁱ ). 10. The method according to claim 9, wherein at the correction stage the power of the infrared heater IR ⁱ is also adjusted so that the wet film reaches the corrected temperature T _c ⁱ in the section P ⁱ of the width of the moving strip downstream from the infrared heater IR ⁱ and upstream from the ultraviolet curing device. 11. The method according to paragraph 9, wherein: - the ultraviolet curing device comprises a set of UV, UV', UV'' … UV ⁱ UV radiation modules, forming a row essentially parallel to the path width P; - at the installation stage, the maximum temperature T _max is set for the specified radiation-curing paint; - at the data collection stage, data on the doses D, D', D'' … D ⁱ of UV radiation of the UV radiation modules are collected; - the adjustment stage includes sub-stages, at which: evaluate whether T _c ⁱ exceeds T _max , if not superior, adjusting the power of the infrared heater IR ⁱ so that the wet film reaches the corrected temperature T _c ⁱ in the section P ⁱ of the width of the moving strip downstream of the infrared heater IR ⁱ and upstream of the ultraviolet curing device, if T _c ⁱ exceeds T _max , The corrected UV dose D _c ⁱ to be delivered to the wet film in the width section P ⁱ in the UV ⁱ module is determined, taking into account the collected UV dose data D ⁱ , the measured gloss G ⁱ and the specified gloss value G _s , based on the preliminary calibration. 12. The method according to claim 11, wherein at the correction stage the power of the UV ⁱ UV radiation module is adjusted in such a way that the wet film in the section P ⁱ of the width of the moving strip receives a corrected dose D _c ⁱ of UV radiation. 13. The method according to paragraph 11, wherein: - UV radiation modules are movable along the path P independently of each other; - at the installation stage, the maximum dose D _max of UV radiation that the wet film can receive in the UV radiation modules is set; - at the data collection stage, data of lengths L, L', L'' … L ⁱ between the UV radiation modules and the electron beam curing device are collected; - the adjustment stage includes sub-stages, at which: if T _c ⁱ exceeds T _max : evaluate whether D _c ⁱ exceeds the value D _max , if it does not exceed, adjust the power of the UV ⁱ UV radiation module so that the wet film in the section P ⁱ of the width of the moving strip receives a dose D _{c i} ^of UV radiation in the UV ⁱ UV radiation module, if D _c ⁱ exceeds D _max , the corrected length L _c ⁱ between the UV ⁱ UV radiation module and the electron beam curing device is determined taking into account the collected values of the length L ⁱ , the measured gloss G ⁱ and the specified gloss value G _s , based on the preliminary calibration. 14. The method according to claim 13, wherein at the adjustment stage the length between the UV ⁱ UV radiation module and the electron beam curing device is adjusted in such a way that a gloss with a value of G _s is obtained on the organic coating in a section of width P ⁱ downstream of the electron beam curing device. 15. A coil coating line comprising a sequentially arranged paint application device, a heating device comprising an infrared heater, an ultraviolet curing device and an electron beam curing device, wherein the coil coating line also comprises a gloss control tool for controlling the gloss of an organic coating formed by applying and curing a wet film of radiation-curable paint on a moving strip of the coil coating line, wherein the gloss control tool comprises: - a module for setting a given value of the gloss G _s of the organic coating, a given range R _s of the gloss of the organic coating and a proportionality constant K of a given linear mathematical relationship between the temperature of the wet film before ultraviolet curing and the gloss of the organic coating after electron beam curing, wherein the constant K is obtained by preliminary calibration; - a data collection module for collecting data on the measurement of the temperature T of the wet film at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, as well as data on the measurement of the gloss G of the organic coating in at least the specified section of the width downstream of the electron beam curing device; - a correction module for correcting the deviation of the measured gloss G outside the specified gloss range R _s , wherein the correction includes calculating the corrected temperature T _c , which the wet film must reach in at least the specified width section downstream of the infrared heater and upstream of the ultraviolet curing device, according to equation 1 T _s = T + K (G - G _s ) ... (1). 16. The method according to claim 1, wherein the adjustment step includes a sub-step in which the settings of the coating line for the rolled metal are adjusted taking into account the calculated adjusted temperature T _c . 17. The method according to claim 5, wherein the adjustment step includes a sub-step in which the setting of the coating line on the rolled product is adjusted, other than the power of the infrared heater, taking into account the calculated adjusted dose D _c of UV radiation. 18. The method according to claim 7, wherein the adjustment step includes a sub-step in which the setting of the coating line on the rolled product is adjusted, other than the power of the infrared heater and the power of the UV radiation module, taking into account the calculated adjusted value of the length L _c . 19. The method according to claim 9, wherein the adjustment step includes a sub-step in which the adjustment of the line for applying the coating to the rolled product is adjusted taking into account the calculated adjusted temperature T _c ⁱ . 20. The method according to claim 11, wherein the adjustment step includes a sub-step in which the setting of the coating line on the rolled product is adjusted, different from the power of the infrared heater IR ⁱ , taking into account the calculated adjusted dose D _c ⁱ of UV radiation. 21. A method for forming an organic coating on a moving strip on a line for applying coating to rolled metal, comprising, sequentially arranged along the path P of the moving belt: a device for applying paint, a heating device containing an infrared heater, an ultraviolet curing device and an electron beam curing device, comprising the steps of: - apply a wet film of radiation-curable paint to a moving strip using a paint application device; - heat the wet film of radiation-curable paint in an infrared heater; - apply UV radiation to a wet film of radiation-curable paint in a UV curing device; - harden a wet film of radiation-curable paint in an electron beam curing device to form an organic coating; In this case, the gloss of the organic coating is controlled by means of the following: - set the specified value G _s of the gloss of the organic coating, the specified range R _s of the gloss for the organic coating and the constant K of proportionality of the specified linear mathematical relationship between the temperature of the wet film before ultraviolet curing and the gloss of the organic coating after electron beam curing, wherein the constant K is obtained by preliminary calibration; - collecting data on the measurement of the temperature T of the wet film at least in a section of the width of the moving strip downstream of the infrared heater and upstream of the ultraviolet curing device, and also collecting data on the measurement of the gloss G of the organic coating in at least the specified section of the width downstream of the electron beam curing device; - correcting the deviation of the measured gloss G beyond the specified gloss range R _s , wherein this correction step includes a sub-step in which the corrected temperature T _c , which the wet film must reach in at least the specified width section downstream of the infrared heater and upstream of the ultraviolet curing device, is calculated according to equation 1 T _s = T + K (G - G _s ) ... (1).