JP-2026514458-A - Method for controlling the gloss of the coating on a coil coating line

JP2026514458AJP 2026514458 AJP2026514458 AJP 2026514458AJP-2026514458-A

Abstract

The present invention relates to a method for managing the gloss of an organic coating formed on a moving strip on a coil coating line which sequentially comprises a paint applicator, a cooling device with a cooling module, an ultraviolet curing device, and an electron beam curing device, wherein the method includes correcting a deviation of the measured gloss G that exceeds a set gloss range R s , and the correction method includes a sub-step of calculating a correction CP to be applied to the output of the cooling module, taking into account G s and the measured gloss G using a closed-loop controller, and a sub-step of adjusting the settings of the coil coating line taking into account the calculated correction CP .

Inventors

ファリーナ，ファブリス
マレゴール，ジャッキー
アンケ，シャルル
デファイズ，トーマス
アルバラシン，マリア
ルウェット，バンサン

Assignees

アルセロールミタル

Dates

Publication Date: 20260511
Application Date: 20240327
Priority Date: 20230406

Claims (15)

A method for controlling the gloss of an organic coating formed by sequentially applying and curing a RadCure coating onto a wet film on a moving strip on a coil coating line, which comprises a coating applicator, a cooling device with a cooling module, an ultraviolet curing device, and an electron beam curing device, along a path P of the moving strip, A step of setting the set gloss value G s and the set gloss range R s of the organic coating, A step of collecting measurements of the gloss G of an organic coating in at least one width portion downstream of an electron beam curing device, A process for correcting a deviation of measured gloss G that exceeds a set gloss range R s , the correction process comprising: a sub-step of calculating a corrective CP applied to the output of a cooling module, taking into account G s and the measured gloss G using a closed-loop controller; and a sub-step of adjusting the coil coating line settings, taking into account the calculated corrective CP . A method for controlling the gloss of organic coatings, including
The method according to claim 1, wherein the closed-loop controller is a proportional-integral-derivative controller.
The method according to any one of claims 1 or 2, wherein the corrected CP is a function of the difference between Gs and the measured gloss G.
The correction CP applied to the output of the cooling module is given by Equation 1 It is calculated according to the following formula, where Kp is the proportional gain, Ki is the integral gain, Kd is the differential gain, and e1 is the difference between Gs and the measured gloss G. The method according to any one of claims 1 to 3.
The method according to any one of claim 1 or 2, wherein the collection step further includes collecting measured values of the temperature T of a wet film in at least one width portion of a moving strip downstream of a cooling module and upstream of an ultraviolet curing device, and the correction step further includes a sub-step of calculating a corrected temperature Tc reached by the wet film in at least one width portion downstream of a cooling module and upstream of an ultraviolet curing device.
The corrected temperature Tc is given by Equation 2: T c = f 1 (T, G, G s ) (2) The calculation is performed according to the formula, where the function f₁ is a function of a predetermined mathematical relationship between the temperature of the wet film before UV curing and the gloss of the organic coating after electron beam curing. The method according to claim 5.
The corrected temperature Tc is given by equation 3: T c = T + K (GG s ) (3) The method according to claim 5, calculated according to the method described in claim 5.
The method according to any one of claims 5 to 7, wherein the correction CP is a function of the difference between Tc and the measured temperature T.
The correction CP applied to the output of the cooling module is given by Equation 4 It is calculated according to the following formula, where K'p is the proportional gain, K'i is the integral gain, K'd is the differential gain, and e² is the difference between Tc and the measured temperature T. The method according to any one of claims 5 to 7.
The method according to any one of claims 1 to 9, wherein a sub-step for adjusting the coil coating line settings includes adjusting the output of the cooling module by a corrective CP .
The UV curing device is equipped with a UV module. The setup process further includes setting the minimum temperature T min of the Radcure paint. The collection process further includes the step of collecting the UV dose D of the UV module, The sub-process for adjusting the coil coating line settings is: Evaluate whether Tc is less than Tmin , If it does not fall below this level, the output of the cooling module is adjusted by the correction Cp . If TC is less than T min : Formula 5: C D = f 2 (G, G s ) (5) Accordingly, calculate the corrected CD applied to the UV dose to which the wet film within at least one width portion in the UV module must be exposed. This includes adjusting the settings of the coil coating lines other than the cooling module output, taking into account the calculated correction C/ D . The method according to any one of claims 5 to 9.
The method according to claim 11, wherein a sub-step for adjusting the settings of the coil coating line other than the output of the cooling module includes adjusting the output of the UV module so that the wet film of at least one width portion of the moving strip is exposed to a corrected UV dose D c = D + C D.
The UV module is movable along path P. The setup step further includes setting the minimum UV dose D min to which the wet film can be exposed in the UV module. The collection step further includes a step of collecting the length L between the UV module and the electron beam curing device, The sub-process for adjusting the coil coating line settings other than the output of the cooling device is: Evaluate whether D + C D is less than D min . If it does not fall below this value, adjust the output of the UV module so that the wet film within at least one width portion of the moving strip is exposed to the corrected UV dose D c = D + C D. If D + C and D is less than D min : Formula 6: C L = f 3 (G, G s ) (6) The correction CL applied to the length between the UV module and the electron beam curing device is calculated accordingly. This includes a sub-process to adjust the settings of the coil coating lines other than the output of the cooling module and the output of the UV module, taking into account the calculated correction CL . The method according to claim 11.
The method according to claim 13, wherein a sub-step for adjusting the settings of coil coating lines other than the output of the cooling module and the output of the UV module includes adjusting the length between the UV module and the electron beam curing device to a corrected length L c = L + C L , thereby obtaining a gloss of value G s on the organic coating in at least one width portion of the moving strip downstream of the electron beam curing device.
A coil coating line comprising, in sequence, a paint applicator, a cooling device with a cooling module, an ultraviolet curing device, and an electron beam curing device, wherein the coil coating line further comprises a gloss control tool for controlling the gloss of an organic coating formed by the application and curing of Radcure paint onto a wet film on a moving strip on the coil coating line, and the gloss control tool is A setting module for setting the gloss value G s and the gloss range R s of the organic coating, An acquisition module for collecting measurements of gloss G of an organic coating in at least one width portion downstream of an electron beam curing device, A correction module for correcting deviations in measured gloss G that exceed a set gloss range R s , wherein the correction includes a sub-step of calculating a correction CP applied to the output of a cooling module, taking into account G s and the measured gloss G using a closed-loop controller, and a sub-step of adjusting the coil coating line settings, taking into account the calculated correction CP , A coil coating line equipped with this feature.

Description

This invention relates to a method for controlling the gloss of an organic coating applied to a moving strip on a coil coating line. In particular, the moving strip is a metal-coated steel strip. Coil coating is a continuous, automated process for coating metal before manufacturing the final product. Steel or aluminum substrates are delivered from a rolling mill in coil form. The metal coil is placed at the beginning of the coil coating line, and in one continuous process, the coil is unwound, pre-cleaned, pre-treated, pre-primed, pre-painted, then wound around the other end and packaged for shipment. The product obtained through this process is pre-coated metal, also known as coil-coated metal, pre-finished metal, or pre-coated metal. It is commonly used in building applications and fixtures. The paints conventionally used for coil coatings are solvent-based. Nevertheless, recently, there has been growing interest in radiation curing, which involves curing materials using ultraviolet (UV) or electron beam (EB) curing processes. Corresponding paints, known as RadCure paints, are solvent-free, and the curing process is induced by either exposure to high-energy UV light, sometimes combined with a suitable photoinitiator, or exposure to accelerated electrons. The photoinitiator absorbs UV light and generates free radicals. The latter react with the double bonds of monomers, causing chain reactions and polymerization. For UV-C and electron beam (EB) curing, initiators are not required. The high radiant energy generates enough reactive species (radicals) for polymerization to proceed spontaneously. One of the unique characteristics of Radocure paints is that they produce an organic coating with high gloss due to the high tension of the coating surface. To reduce this gloss and meet the requirements of the pre-coating market (in the construction market, gloss is typically 15 GU to 30 GU), paint suppliers add matting agents, similar to those used with solvent-based paints. However, because Radocure paints are highly viscous due to the absence of solvents, only small amounts of matting agents can be added, and low gloss levels are not tolerable. Furthermore, the migration of matting agents to the coating surface to achieve the desired gloss level is also severely limited compared to solvent-based paints due to the curing process speed of Radocure paints (1-2 seconds vs. 12-25 seconds). One method to mitigate this challenge is known from International Publication No. 81/00683, which discloses a curing process in which the coating is first irradiated with curing radiation (such as UV) at a wavelength to which the coating responds, substantially lacking a distribution below approximately 300 nm, and then irradiated with curing radiation at a wavelength to which the coating responds, including substantially radiation (such as EB) with wavelengths below 300 nm. This double curing is known as dual curing. Gloss control is achieved by adjusting online parameters including the spectral distribution, intensity, or dose of the initial radiation, or the time interval between the initial and subsequent irradiation steps. Nevertheless, it has been observed that these online parameters are insufficient for controlling gloss in an efficient and reproducible manner. International Publication No. 81/00683 This is a schematic diagram of the coil coating line.This is a flowchart of a first embodiment of the method according to the present invention.This is a flowchart of a second embodiment of the method according to the present invention.This is a flowchart of a third embodiment of the method according to the present invention. Please note that the spatially relative terms used in this application, such as "upstream," "downstream," "lower," "upper," "upper," "downward," "before," and "after," refer to the positions and orientations of different components of the coil coating line. The method according to the present invention applies to strips such as metal strips. Examples of metal strips include steel, carbon steel, or stainless steel, as well as aluminum and copper. In particular, steel strips may be exposed, or they may be coated with a metal coating on one or both sides. Examples of possible metal-coated steels include galvanized steel, steel coated with a zinc alloy containing 5% by weight of aluminum (Galfan®), steel coated with a residue consisting of 55% by weight of aluminum, approximately 1.5% by weight of silicon, zinc, and unavoidable impurities resulting from processing (Aluzinc®, Galvalume®), steel coated with aluminum containing 8–11% by weight of silicon and 2–4% by weight of iron, aluminum, and unavoidable impurities resulting from processing (Alusi®), steel coated with an aluminum layer (Alupur®), steel coated with a zinc alloy containing 0.5–20% aluminum and 0.5–10% magnesium, zinc, and unavoidable impurities resulting from processing, and steel coated with an alloy containing aluminum, magnesium, silicon, potent