JP2012006006A - Continuous coating treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous coating treatment method which is capable of acquiring both a desired film thickness and a good coating appearance with constant stabilization in conducting the continuous coating treatment to the substrate using a roll coater.SOLUTION: In performing the film thickness control by the feedback control that adjusts the peripheral velocity Vp of a pick-up roll 4, the peripheral velocity Vd of a doctor roll 5 and the peripheral velocity Va of an applicator roll 6 automatically in accordance with the difference between the measured value of a film thickness meter 11 installed at the downstream side of the roll coater 1A and the set value of the film thickness that is set previously, the continuous coating treatment method comprises setting the upper and lower limits about the peripheral velocities Vp, Vd, Va of each roll 4, 5, 6 and performing the film thickness control by only the adjustment of the peripheral velocity Vd of the doctor roll 5 when the feedback control is initiated, and performing the film thickness control by the adjustment of the peripheral velocity Vp of the pick-up roll 4 and/or the peripheral velocity Va of the applicator roll 6 after the peripheral velocity Vd of the doctor roll 5 reaches the upper and lower limits.

Description

  The present invention relates to a continuous coating treatment method in which a coating treatment is continuously performed on a substrate.

  Conventionally, in order to impart performance such as corrosion resistance, workability, aesthetics, insulation, etc. to a continuously running substrate (for example, a steel plate), various coating films are formed on the substrate surface (continuous coating treatment) )It is carried out. In this continuous coating method, a roll coater method is generally used, and a two-roll coater using two rolls or a three-roll coater using three rolls is widely used. In particular, the 3-roll coater has a mainstream roll coater system because it has excellent controllability of the coating film thickness and has a relatively beautiful surface appearance.

  This three-roll coater method is a pickup roll that draws up the coating liquid from the coater pan filled with the coating liquid, a doctor roll that adjusts the amount of the coating liquid drawn up by the pickup roll, and the adjusted amount of the coating liquid that is picked up by the roll. It is comprised by the applicator roll transcribe | transferred to a base material. The rotation direction of each roll may be the reverse rotation that rotates in the opposite direction to the natural rotation that rotates in the same direction at the proximity point between the rolls or the contact point, but in general the reverse rotation is compared In many cases, a reverse rotation is used because it is easy to obtain a smooth coating surface. The applicator roll uses a rubber roll in which rubber is lined on a steel roll so as not to damage the surface of the substrate.

  In the case of a coating liquid having a relatively low viscosity, the amount of liquid passing through between the pickup roll and the doctor roll is reduced, and therefore a gravure roll having a groove surface on the roll surface is often used for the pickup roll. Gravure patterns include diagonal V-groove patterns and patterns in which the apexes of the quadrangular pyramids become groove troughs. The type of gravure pattern and groove size depend on the type of coating solution and the required film thickness. As appropriate.

  In order to keep a constant film thickness against changes in the running speed of the substrate, changing the peripheral speed of each coater roll is the quickest method, so changing the peripheral speed of each coater roll, In many cases, the thickness is controlled. When controlling the film thickness, measure the film thickness with a film thickness meter installed on the downstream side of the roll coater. Is adjusted (see, for example, Patent Document 1).

JP-A-3-177578

  However, in the continuous coating process by the roll coater method, even if the film thickness is simply within the control range, the appearance may be poor due to coating defects. That is, even if the target film thickness is obtained by performing automatic film thickness control, the appearance may be defective.

  The present invention has been made in view of the circumstances as described above. When a coating process is continuously performed on a substrate using a roll coater, the coating film is always stably provided with a desired film thickness and a good coating appearance. It aims at providing the continuous application | coating processing method which can obtain both.

  In order to solve the above problems, the present invention has the following features.

[1] The coating liquid is pumped up by a pickup roll, the amount of the coating liquid on the pickup roll is adjusted by a doctor roll, and the coating liquid is applied from the pickup roll to an applicator roll that rotates in a reverse direction at a point close to the doctor roll. In the continuous coating treatment method by a roll coater that transfers and further transfers the coating liquid from the applicator roll to the substrate that runs continuously,
When performing film thickness control by feedback control that automatically adjusts the peripheral speed of each roll according to the difference between the measured value of the film thickness meter installed downstream of the roll coater and the preset film thickness setting value The upper and lower limits are set for the peripheral speed of each roll, and when starting the feedback control, the film thickness is controlled by adjusting only the peripheral speed of the doctor roll, and the peripheral speed of the doctor roll is After reaching the lower limit, the film thickness is controlled by adjusting the peripheral speed of the pickup roll and / or adjusting the peripheral speed of the applicator roll.

[2] The coating liquid is pumped up by the pickup roll, the amount of the coating liquid on the pickup roll is adjusted by the doctor roll, and the coating liquid is applied from the pickup roll to the applicator roll that rotates in the same direction at a point close to the doctor roll. In the continuous coating treatment method by a roll coater that transfers and further transfers the coating liquid from the applicator roll to the substrate that runs continuously,
When performing film thickness control by feedback control that automatically adjusts the peripheral speed of each roll according to the difference between the measured value of the film thickness meter installed downstream of the roll coater and the preset film thickness setting value The upper and lower limit values are set for the peripheral speed of the pickup roll and the peripheral speed of the applicator roll, and the film thickness is controlled by adjusting the peripheral speed of the pick-up roll and / or adjusting the peripheral speed of the applicator roll. A continuous coating treatment method characterized by the above.

  [3] The continuous coating treatment method according to [1] or [2], wherein an alarm is output when any of the peripheral speeds of the rolls reaches an upper and lower limit value.

  In the present invention, when the coating treatment is continuously performed on the substrate, it is always possible to stably obtain both a desired film thickness and a good coating appearance.

It is a side view of the continuous application processing line in Embodiment 1 of the present invention. It is a side view of the continuous application | coating process line in Embodiment 2 of this invention. It is the figure which compared this invention example 3 and comparative example 3 in Example 1 of this invention. It is the figure which compared this invention example 4 and comparative example 4 in Example 1 of this invention.

  Embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
FIG. 1 is a side view showing a continuous coating treatment line in Embodiment 1 of the present invention.

  As shown in FIG. 1, a reverse rotation type three-roll coater 1 </ b> A is installed in this continuous coating treatment line in order to apply a coating solution to the surface of the substrate S that runs continuously.

  The three-roll coater 1A includes a pickup roll 4 that draws up the coating liquid 3 from the coater pan 2, a doctor roll 5 that adjusts the amount of the coating liquid 3 on the pickup roll 4, and the adjusted coating liquid on the pickup roll 4. An applicator roll 6 for transferring 3 to the substrate S is provided. The substrate S is applied in a state of being wound around the backup roll 8.

  And the rotation direction of each roll (pickup roll 4, doctor roll 5, applicator roll 6) is mutually opposite between each roll or between the applicator roll 6 and the base material S. A blade 7 that scrapes the coating solution 3 is installed on the doctor roll 5.

  When the substrate S is a metal plate such as a steel plate, the applicator roll 6 uses a rubber roll lined with rubber. The pick-up roll 4 uses a gravure roll that is grooved on the roll surface.

  On the downstream side of the 3-roll coater 1A, an oven 9 for drying and baking the coating liquid 3 and a cooling zone 10 for cooling after heating are installed.

  A film thickness meter 11 is installed on the downstream side of the cooling zone 10, and the output of the film thickness meter 11 is input to the arithmetic unit 12, and the peripheral speed control device 13 is set so as to have a preset target film thickness. The peripheral speed of each roll (the pickup roll 4, the doctor roll 5, and the applicator roll 6) is automatically adjusted by automatic control (feedback control).

  In addition, in the reverse rotation type three-roll coater 1A as described above, the following knowledge was obtained as a result of detailed examination of the generation mechanism of the coating defect that deteriorates the coating appearance.

  That is, the location where the coating defect occurs is a meniscus portion between the pickup roll 4 and the applicator roll 6 and between the applicator roll 6 and the substrate S. As for the former, when the peripheral speed Va of the applicator roll 6 becomes too high with respect to the peripheral speed Vp of the pickup roll 4, a coating defect occurs. Also in the latter case, when the traveling speed (line speed) LS of the base material S becomes too high with respect to the peripheral speed Va of the applicator roll 6, a coating defect occurs.

  Therefore, in order not to cause a coating defect, both the peripheral speed Vp of the pickup roll 4 and the peripheral speed Va of the applicator roll 6 must be within an appropriate peripheral speed range. That is, the upper and lower limit values of the peripheral speed Va of the applicator roll 6 are set with respect to the traveling speed LS of the substrate S, and the peripheral speed of the pickup roll 4 is set in accordance with the upper and lower limit values of the peripheral speed Va of the applicator roll 6. Set upper and lower limits of speed Vp. Specifically, for the peripheral speed Va of the applicator roll 6 and the peripheral speed Vp of the pickup roll 4, the lower limit value is determined under conditions that do not cause coating defects, and the upper limit value is determined by the maximum peripheral speed of each roll.

  On the other hand, the peripheral speed Vd of the doctor roll 5 does not cause any coating defects, and therefore there is no need to particularly define the upper and lower limit range. Therefore, the upper limit value may be the maximum peripheral speed of the doctor roll 5, and the lower limit value may be the minimum peripheral speed of the doctor roll 5.

  The change in the peripheral speed of the doctor roll 5 is most suitable for controlling the film thickness because it does not affect the coating appearance unlike the applicator roll 6 and the pickup roll 4.

  Therefore, immediately after the start of the automatic control (feedback control), the film thickness is first controlled by changing / adjusting the peripheral speed Vd of the doctor roll 5, and when the film thickness cannot be controlled only by the peripheral speed Vd of the doctor roll 5, That is, when the peripheral speed Vd of the doctor roll 5 reaches the upper and lower limit values, the control is switched to film thickness control for changing / adjusting the peripheral speed Vp of the pickup roll 4 and / or the peripheral speed Va of the applicator roll 6. As described above, the coating appearance is further stabilized by performing the film thickness adjustment by changing or adjusting the peripheral speed Vd of the doctor roll 5 to the maximum extent.

  In this way, in the first embodiment, when the coating process is continuously performed on the substrate S, both a desired film thickness and a good coating appearance can be obtained stably.

  That is, in the first embodiment, the film thickness can be controlled in the peripheral speed range of each roll so as not to cause a coating defect, and variations in the film thickness can be reduced. A manufacturing method has been established in which a desired film thickness can be obtained and the film thickness target value can be reduced. Therefore, according to the first embodiment, stable quality can always be obtained without operator intervention, labor saving can be achieved, and the manufacturing cost can be reduced.

[Embodiment 2]
FIG. 2 is a side view showing a continuous coating treatment line in Embodiment 2 of the present invention.

  As shown in FIG. 2, this continuous coating treatment line is basically the same as the continuous coating treatment line shown in FIG. 1, but a part of the continuous coating treatment line is natural instead of the reverse rotation type three-roll coater 1A. A three-roll coater 1B that is rotating is installed.

  That is, the three-roll coater 1B is a three-roll coater in which the rotation direction of the doctor roll 5 is opposite to that of the three-roll coater 1A, and the pickup roll 4 and the doctor roll 5 rotate in the same direction at the proximity point.

  In addition, as a result of detailed examination of the generation mechanism of the coating defect that deteriorates the coating appearance in the partial natural rotation type 3 roll coater 1B as described above, the partial natural rotation type 3 roll coater 1B also has a result. It has been found that the occurrence location of the coating defect is a meniscus portion between the pickup roll 4 and the applicator roll 6 and between the applicator roll 6 and the substrate S. As for the former, when the peripheral speed Va of the applicator roll 6 becomes too high with respect to the peripheral speed Vp of the pickup roll 4, a coating defect occurs. Also in the latter case, when the traveling speed (line speed) LS of the base material S becomes too high with respect to the peripheral speed Va of the applicator roll 6, a coating defect occurs.

  Therefore, in order not to cause a coating defect, both the peripheral speed Vp of the pickup roll 4 and the peripheral speed Va of the applicator roll 6 must be within an appropriate peripheral speed range. That is, the upper and lower limit values of the peripheral speed Va of the applicator roll 6 are set with respect to the traveling speed LS of the substrate S, and the peripheral speed of the pickup roll 4 is set in accordance with the upper and lower limit values of the peripheral speed Va of the applicator roll 6. Set upper and lower limits of speed Vp. Specifically, for the peripheral speed Va of the applicator roll 6 and the peripheral speed Vp of the pickup roll 4, the lower limit value is determined under conditions that do not cause coating defects, and the upper limit value is determined by the maximum peripheral speed of each roll.

  On the other hand, the influence of the peripheral speed Vd of the doctor roll 5 on the film thickness is small, and the film thickness control by changing or adjusting the peripheral speed Vd of the doctor roll 5 is not appropriate.

  Therefore, the film thickness is controlled by changing / adjusting the peripheral speed Vp of the pickup roll 4 and the peripheral speed Va of the applicator roll 6. At that time, similarly to Embodiment 1, upper and lower limits are provided for each roll (pickup roll 4 and applicator roll 6).

  As described above, in the second embodiment, when the coating process is continuously performed on the substrate S, both a desired film thickness and a good coating appearance can be obtained stably.

  That is, in the second embodiment, the film thickness can be controlled in the peripheral speed range of each roll so as not to cause a coating defect, and the variation in the film thickness can be reduced. A manufacturing method has been established in which a desired film thickness can be obtained and the film thickness target value can be reduced. Therefore, according to the second embodiment, stable quality is always obtained even without operator intervention, labor saving is possible, and the manufacturing cost is reduced.

  Further, in the first embodiment and the second embodiment, when any of the peripheral speeds Vp, Vd, Va of the rolls 4, 5, 6 reaches the upper and lower limit values of the roll, an alarm is output, and the operator By making it known, it is urged that the peripheral speed of each roll is out of the proper range and there is a possibility that a coating defect may occur, and the continuous generation of coating defects can be prevented.

  In the first and second embodiments, as shown in FIGS. 1 and 2, the base material S is applied to one side in a state of being wound around the backup roll 8. It can also be applied to double-sided simultaneous coating in which a three-roll coater is disposed on both sides with no backup roll required. Further, the plate-passing direction of the substrate S may be either a horizontal pass or a vertical pass.

  In the first and second embodiments, the roll coater using three rolls has been described. However, one or more intermediate rolls may be sandwiched between the pick-up roll and the applicator roll.

  In the first and second embodiments, the supply of the coating liquid to the pickup roll is described as the coating liquid being scraped from the coater pan, but other coating liquid supply methods such as spraying and extrusion may be used.

  Furthermore, in the first and second embodiments, the example in which the film thickness meter installed on the downstream side of the roll coater is installed at the position after drying is shown, but the present invention is not limited to this and is measured in a liquid film state. In the case of a film thickness meter to be used, it may be installed at a position before drying and converted into a film thickness after drying. Further, the film thickness meter is not particularly limited as long as the film thickness or the adhesion amount can be measured.

  The present invention will be described in detail by the following examples (invention examples and comparative examples).

  As Example 1 of the present invention, a line speed LS of 40 to 40 is used for a coil of a galvanized steel sheet having a thickness of 0.4 to 1.2 mm and a width of 900 to 1400 mm using the continuous coating treatment line shown in FIG. Coating was performed in the range of 120 mpm, and the coating appearance after drying was evaluated and the film thickness was measured by fluorescent X-rays. The appearance of the coating after drying was evaluated by visual observation under a sufficiently bright fluorescent lamp.

  At that time, the three-roll coater 1A of FIG. 1 is a rubber roll in which the applicator roll 6 and the doctor roll 5 line a rubber with a steel roll, and the pickup roll 4 is a metal roll and rolls on the roll surface. The gravure roll was subjected to V-shaped groove processing (pitch 0.2 mm, depth 0.1 mm) at an angle of 45 degrees with respect to the circumferential direction. The roll diameters of the rolls 4, 5, and 6 were all 300 mm, and the pressing load between the rolls and between the applicator roll 6 and the steel sheet S was 200 kg. A coating solution having a viscosity of 1 cp and a surface tension of 40 dyn / cm at a liquid temperature of 20 ° C. was used.

  The upper and lower limit values are set for the peripheral speeds Vp, Vd, and Va of the rolls 4, 5, and 6, and automatic control is performed so that the measured value of the film thickness meter 11 becomes the film thickness setting value ( Feedback control) was performed. At that time, at the start of automatic control, only the peripheral speed Vd of the doctor roll 5 is changed / adjusted. When the peripheral speed Vd of the doctor roll 5 reaches the upper and lower limit values, the peripheral speed Vp of the pickup roll 4 is The peripheral speed Va of the applicator roll 6 is simultaneously changed and adjusted.

  Table 1 shows the upper and lower limit values set for the peripheral speeds Vp, Vd, and Va of the rolls 4, 5, and 6, respectively. Note that an alarm is output when any of the peripheral speeds Vp, Vd, and Va of the rolls 4, 5, and 6 reaches the upper and lower limit values.

  On the other hand, as a comparative example 1, under the same conditions as in the present invention example 1, the operator can change the circumferential speed Vp of each of the rolls 4, 5, and 6 with respect to the change of the line speed LS as in the prior art. , Vd, and Va were changed and adjusted to control the film thickness.

  In addition, as Example 2 of the present invention, a coil of a galvanized steel sheet having the same size as described above was applied using a continuous coating treatment line shown in FIG. 2 in a range of a line speed LS of 40 to 120 mpm and dried. Evaluation of the subsequent coating appearance and film thickness measurement by fluorescent X-ray were performed. The appearance of the coating after drying was evaluated by visual observation under a sufficiently bright fluorescent lamp.

  At that time, the material of each roll of the 3-roll coater 1B in FIG. 2 was a rubber roll in which the applicator roll 6 and the doctor roll 5 lined rubber on a steel roll, and the pickup roll 4 was a mirror-like metal roll. The roll diameter of each roll was 300 mm, and the pressing load between each roll and between the applicator roll 6 and the steel sheet S was 200 kg. A coating solution having a viscosity of 8 cp and a surface tension of 40 dyn / cm at a solution temperature of 20 ° C. was used.

  The upper and lower limit values are set for the peripheral speeds Vp and Va of the rolls 4 and 6, and automatic control (feedback control) is performed so that the measured value of the film thickness meter 11 becomes the film thickness setting value. Carried out. At that time, the automatic control changes and adjusts the peripheral speed Vp of the pickup roll 4 and the peripheral speed Va of the applicator roll 6 at the same time.

  Table 2 shows the upper and lower limit values set for the peripheral speeds Vp and Va of the rolls 4 and 6. Note that an alarm is set to be output when either of the peripheral speeds Vp and Va of the rolls 4 and 6 reaches the upper and lower limit values.

  On the other hand, as a comparative example 2, under the same conditions as in the present invention example 2, the peripheral speed Vp of each of the rolls 4, 5, 6 is changed by the operator with respect to the change of the line speed LS as in the past. , Vd, and Va were changed and adjusted to control the film thickness.

  In addition, as Example 3 of the present invention, a coil of a galvanized steel sheet having the same size as described above was applied using a continuous coating treatment line shown in FIG. 1 in a range of a line speed LS of 40 to 120 mpm and dried. Evaluation of the subsequent coating appearance and film thickness measurement by fluorescent X-ray were performed. The appearance of the coating after drying was evaluated by visual observation under a sufficiently bright fluorescent lamp.

  At that time, the three-roll coater 1A of FIG. 1 is a rubber roll in which the applicator roll 6 and the doctor roll 5 line a rubber with a steel roll, and the pickup roll 4 is a metal roll and rolls on the roll surface. The gravure roll was subjected to V-shaped groove processing (pitch 0.2 mm, depth 0.1 mm) at an angle of 45 degrees with respect to the circumferential direction. The roll diameters of the rolls 4, 5, and 6 were all 300 mm, and the pressing load between the rolls and between the applicator roll 6 and the steel sheet S was 70 kg. A coating solution having a viscosity of 24 cp and a surface tension of 40 dyn / cm at a solution temperature of 20 ° C. was used.

  The upper and lower limit values are set for the peripheral speeds Vp, Vd, and Va of the rolls 4, 5, and 6, and automatic control is performed so that the measured value of the film thickness meter 11 becomes the film thickness setting value ( Feedback control) was performed. At that time, at the start of automatic control, only the peripheral speed Vd of the doctor roll 5 is changed / adjusted. When the peripheral speed Vd of the doctor roll 5 reaches the upper and lower limit values, the peripheral speed Vp of the pickup roll 4 is The peripheral speed Va of the applicator roll 6 is simultaneously changed and adjusted.

  Table 3 shows the upper and lower limit values set for the peripheral speeds Vp, Vd, and Va of the rolls 4, 5, and 6, respectively. Note that an alarm is output when any of the peripheral speeds Vp, Vd, and Va of the rolls 4, 5, and 6 reaches the upper and lower limit values.

  On the other hand, as a comparative example 3, under the same conditions as in the present invention example 3, the operator can change the circumferential speed Vp of each of the rolls 4, 5, 6 with respect to the change of the line speed LS as in the past. , Vd, and Va were changed and adjusted to control the film thickness.

  In addition, as Example 4 of the present invention, a coil of a galvanized steel sheet having the same size as described above was applied using a continuous coating treatment line shown in FIG. 2 in a range of a line speed LS of 40 to 120 mpm, and dried. Evaluation of the subsequent coating appearance and film thickness measurement by fluorescent X-ray were performed. The appearance of the coating after drying was evaluated by visual observation under a sufficiently bright fluorescent lamp.

  At that time, the material of each roll of the 3-roll coater 1B in FIG. 2 was a rubber roll in which the applicator roll 6 and the doctor roll 5 lined rubber on a steel roll, and the pickup roll 4 was a mirror-like metal roll. The roll diameter of each roll was 300 mm, and the pressing load between each roll and between the applicator roll 6 and the steel sheet S was 70 to 100 kg. A coating solution having a viscosity of 40 cp and a surface tension of 40 dyn / cm at a solution temperature of 20 ° C. was used.

  The upper and lower limit values are set for the peripheral speeds Vp and Va of the rolls 4 and 6, and automatic control (feedback control) is performed so that the measured value of the film thickness meter 11 becomes the film thickness setting value. Carried out. At that time, the automatic control changes and adjusts the peripheral speed Vp of the pickup roll 4 and the peripheral speed Va of the applicator roll 6 at the same time.

  Table 4 shows the upper and lower limit values set for the peripheral speeds Vp and Va of the rolls 4 and 6. Note that an alarm is set to be output when either of the peripheral speeds Vp and Va of the rolls 4 and 6 reaches the upper and lower limit values.

  On the other hand, as a comparative example 4, under the same conditions as in the above-described invention example 4, the operator can change the circumferential speed Vp of each of the rolls 4, 5, 6 with respect to the change of the line speed LS as in the prior art. , Vd, and Va were changed and adjusted to control the film thickness.

  As a result, in Examples 1 and 2 of the present invention, even when the speed (line speed) LS of the steel sheet S is changed, a good appearance and a stable film thickness are always obtained. Since the deviation could be reduced to 5.8%, the target film thickness that does not fall below the lower limit within the film thickness control range can be lowered, and the average film thickness is lowered by 7.5% compared to the conventional film thickness. I was able to.

  On the other hand, in Comparative Examples 1 and 2, in order to make the film thickness within the control range, a good appearance may not always be obtained, and the standard deviation of the film thickness variation with respect to the film thickness average value is 8.3. It was as big as%. Further, immediately after the change of the line speed LS, the film thickness may be out of the management range.

  Furthermore, FIG. 3 shows a comparison result between Example 3 of the present invention and Comparative Example 3.

  Further, FIG. 4 shows a comparison result between the inventive example 4 and the comparative example 4.

  In Invention Example 4, even in the high-viscosity paint, even if the speed (line speed) LS of the steel sheet S is changed, a stable film thickness with a good appearance can always be obtained. 70%.

  In addition, although the steel plate was used as a base material in this Example, this invention is not specifically limited to a steel plate, It applies to other metal plates, such as aluminum, paper, and a film.

S base material 1A 3 roll coater (reverse rotation type 3 roll coater)
1B 3 roll coater (some natural rotating 3 roll coaters)
2 Coater Pan 3 Coating Liquid 4 Pickup Roll 5 Doctor Roll 6 Applicator Roll 7 Blade 8 Backup Roll 9 Oven 10 Cooling Zone 11 Film Thickness Meter 12 Arithmetic Unit 13 Peripheral Speed Controller

Claims (3)

The application liquid is pumped up by a pickup roll, the amount of the application liquid on the pickup roll is adjusted by a doctor roll, and the application liquid is transferred from the pickup roll to an applicator roll that rotates in a reverse direction at a point close to the doctor roll, Furthermore, in the continuous coating treatment method by the roll coater that transfers the coating liquid from the applicator roll to the substrate that runs continuously,
When performing film thickness control by feedback control that automatically adjusts the peripheral speed of each roll according to the difference between the measured value of the film thickness meter installed downstream of the roll coater and the preset film thickness setting value The upper and lower limits are set for the peripheral speed of each roll, and when starting the feedback control, the film thickness is controlled by adjusting only the peripheral speed of the doctor roll, and the peripheral speed of the doctor roll is After reaching the lower limit, the film thickness is controlled by adjusting the peripheral speed of the pickup roll and / or adjusting the peripheral speed of the applicator roll. The application liquid is pumped up by a pickup roll, the amount of the application liquid on the pickup roll is adjusted by a doctor roll, and the application liquid is transferred from the pickup roll to an applicator roll that rotates in the same direction at a point close to the doctor roll, Furthermore, in the continuous coating treatment method by the roll coater that transfers the coating liquid from the applicator roll to the substrate that runs continuously,
When performing film thickness control by feedback control that automatically adjusts the peripheral speed of each roll according to the difference between the measured value of the film thickness meter installed downstream of the roll coater and the preset film thickness setting value The upper and lower limit values are set for the peripheral speed of the pickup roll and the peripheral speed of the applicator roll, and the film thickness is controlled by adjusting the peripheral speed of the pick-up roll and / or adjusting the peripheral speed of the applicator roll. A continuous coating treatment method characterized by the above.   The continuous coating treatment method according to claim 1, wherein an alarm is output when any of the peripheral speeds of the rolls reaches an upper and lower limit value.

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