JP2008246297A - Continuous application method and continuous application equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous application method capable of suppressing the generation of application defects while adjusting the amount of deposit after drying within a range required from points of corrosion resistance or the like, and continuous application equipment. <P>SOLUTION: The continuous application method includes the step of depositing paint 2 in a coater pan 3 on the surface of a continuously conveying body to be applied 1 by transfer, using an applicator roll 6. The amount of deposit is adjusted so that the amount of deposit Dd after drying becomes within a range of the target amount of dried deposit, and the amount of deposit of the paint applied on the surface of the body to be applied 1 before drying becomes within a range of the preset amount of the target amount of deposit before drying. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a continuous coating processing method and a continuous coating processing facility for performing coating processing using an applicator roll on the surface of an object to be continuously conveyed.

  Conventionally, continuous coating treatment to form various coating films to impart performance such as corrosion resistance, workability, aesthetics, insulation, etc. to the surface of the object to be plated such as steel plates that are continuously conveyed. Is going. As this processing method, for example, as described in Patent Document 1 and Patent Document 2, a roll coater that transfers and applies the coating material transferred to the applicator roll to the object to be plated is used. A two-roll coater that uses this or a three-roll coater that uses three rolls is widely used. In particular, the three-roll coater is a mainstream coating method because it has excellent controllability of the coating film thickness and has a relatively beautiful surface appearance.

  In general, this method consists of a pick-up roll that draws paint from a coater pan filled with paint, a metering roll that adjusts the amount of paint drawn by the pick-up roll, and a transfer of the adjusted amount of paint from the pick-up roll to the steel plate. It is comprised by the applicator roll. 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 the steel roll so as not to damage the steel sheet surface.

  In the case of a paint having a relatively low viscosity, the amount of liquid passing through between the pickup roll and the mitering roll is reduced, so that a gravure roll having a groove surface on the roll surface is used as the pickup roll. Gravure patterns include diagonal V-groove patterns and patterns in which the apexes of the quadrangular pyramids become troughs of the grooves, but the gravure pattern type and groove size depend on the type of paint and the amount of adhesion required. It is decided appropriately.

  Factors that determine the amount of adhesion include the roll peripheral speed, nip pressure between rolls, roll gap, and coating concentration. Of these, roll peripheral speed, nip pressure between rolls, and gaps can always be measured as operating conditions. However, paint concentration is usually measured manually before starting application, and then manually measured by sampling the paint. If the concentration of the paint is out of the control range, the adjustment is made as appropriate.

In addition, the film thickness after coating of the applied paint (equivalent to the amount of adhesion) is measured by a film thickness meter installed on the downstream side of the roll coater, and the film thickness after drying within the target range by feedback control, The factors that determine the amount of adhesion described above, that is, the roll peripheral speed and the like are adjusted.
JP 2005-169317 A Japanese Patent Laid-Open No. 10-249262

However, even if the film thickness of the paint after drying is within the target range, the appearance may be NG due to a coating defect.
In addition, although the wet film thickness is adjusted in the technique of patent document 2, this is for adjusting the range of the film thickness after drying with high precision, and has a different purpose from the present invention.
The present invention has been made paying attention to such points, and is a continuous coating process capable of suppressing the occurrence of coating defects while adjusting the amount of adhesion after drying required from the viewpoint of corrosion resistance and the like. It is an object to provide a method and a continuous coating treatment facility.

  As a result of inventor's earnest study, the amount of wet paint (film thickness, etc.) in the wet state before drying is set within a predetermined range, apart from the amount of paint paint (dry film thickness, etc.) after drying set based on corrosion resistance. The knowledge that the defect of an application | coating external appearance can be suppressed by suppressing was acquired. In particular, when the wet adhesion amount immediately after coating increases, the coating appearance often deteriorates. The present invention is based on such knowledge.

In order to solve the above-described problems, the invention described in claim 1 of the present invention is based on the object to be coated which is continuously conveyed using the applicator roll for the paint in the paint container. Continuous application processing method for adjusting the amount of coating applied so that the amount of adhesion after drying of the paint applied to the surface of the object to be coated falls within the range of the target dry adhesion amount In
The adhesion amount after the drying is within the range of the target dry adhesion amount, and the adhesion amount before drying of the paint applied to the surface of the object to be coated is within the preset target adhesion amount range before the drying. The present invention provides a continuous coating treatment method characterized by adjusting the coating amount.
The application amount may be adjusted by adjusting the factors that determine the known adhesion amount as described above.

Moreover, the invention described in claim 2 transfers the paint in the application container to the applicator roll, and transfers the paint transferred to the applicator roll onto the surface of the object to be continuously conveyed, In continuous application processing equipment that applies paint by applying paint to the object to be coated,
A dry adhesion amount detection means for detecting an adhesion amount after drying of the paint applied to the surface of the object to be coated; a wet adhesion amount detection means for detecting an adhesion amount of the paint applied to the surface of the object to be coated before drying;
Based on the detection information of the dry adhesion amount detection means and the wet adhesion amount detection means, the adhesion amount after drying falls within the predetermined target dry adhesion amount range, and the adhesion amount before drying falls within the target drying amount range. And adjusting means for adjusting at least one of the transfer amount of the paint to the applicator roll, the peripheral speed of the applicator roll, the gap between the applicator roll and the object to be coated, and the concentration of the paint. It is.

  Next, the invention described in claim 3 is the construction described in claim 2, wherein the wet adhesion amount detection means is based on the adhesion amount after drying detected by the dry adhesion amount detection means and the concentration of the paint. The amount of adhesion before drying is obtained.

According to the first or second aspect of the invention, it is possible to always obtain a stable desired adhesion amount and a good coating appearance.
Moreover, according to the invention which concerns on Claim 3, the adhesion amount before drying can be detected actually, and the adhesion amount in the wet state before drying corresponding to the adhesion amount after drying can be calculated | required.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an example of a continuous coating treatment facility in the present embodiment.
(Constitution)
First, the structure will be described. As shown in FIG. 1, the coating is applied to the surface of the object 1 to be continuously passed by a roll coater. In FIG. 1, the case where it applies only to one side of the article 1 is illustrated, but it may be configured to apply to both sides.

The roll coater includes a pick-up roll 4 for picking up the paint 2 from the coater pan 3 which is a paint 2 containing portion containing the paint 2, a mitering roll 5 for adjusting the amount of the paint 2 on the pick-up roll 4, and an adjustment. And an applicator roll 6 that transfers the paint 2 on the pick-up roll 4 to the surface of the body 1 to be coated. Reference numeral 7 denotes a blade for scraping off the paint 2 on the mitering roll.
Here, in this embodiment, the rotation directions of the rolls 4 to 6 are opposite to each other between the rolls 4 to 6 or between the applicator roll 6 and the object 1 to be coated. When the object 1 is a metal plate such as a steel plate, the applicator roll 6 may be a rubber roll lined with rubber. The pickup roll 4 may be a gravure roll having a groove formed on the roll surface.

  Further, FIG. 1 shows a case where the object to be coated 1 is applied in a state of being wound around the backup roll 8, but the backup roll 8 in which roll coaters are arranged on both sides of the object to be coated 1 is illustrated. It is also possible to carry out a double-sided simultaneous coating process that does not require the above. Further, the plate-passing direction of the object 1 may be either a horizontal pass or a vertical pass. Further, in FIG. 1, a three-roll coater type is shown, but a two-roll coater type may be used, and a one-roll coater type may be used in some cases.

Further, the inside of the coater pan 3 and the inside of the supply tank 12 containing the paint 2 are a return path 20 for returning the surplus paint 2 from the coater pan 3 into the supply tank 12, and the coater 2 with the paint 2 in the supply tank 12. The paint 2 can be circulated by being connected by a circulation system including a supply path 21 that supplies the pan 3, and the liquid surface height and concentration of the paint 2 in the coater pan 3 can be adjusted. Yes. Reference numeral 13 denotes a pump interposed in the return path, which pumps the paint 2 in the supply tank 12 toward the coater pan 3.
Reference numeral 17 denotes a dilution tank containing the dilution liquid 16, and the concentration of the paint 2 in the supply tank 12 can be adjusted by appropriately supplying the dilution liquid 16 in the dilution tank 17 to the supply tank 12. It has become. Reference numeral 18 denotes a pump for pumping the diluent 16 to the supply tank 12.

Further, on the downstream side of the roll coater 3, an oven 9 for drying and baking the paint 2 attached to the object to be coated 1 and a cooling zone 10 for cooling the object to be coated 1 after heating are installed.
Further, an adhesion amount meter 11 for detecting the adhesion amount of the paint 2 after drying attached to the surface of the object 1 is set downstream of the cooling zone 10. The adhesion amount meter 11 outputs the detected adhesion amount to the adhesion amount control unit 15. The adhesion amount meter 11 includes, for example, an infrared adhesion amount meter and constitutes a dry adhesion amount detection means.

  In the present embodiment, a densitometer 14 for detecting the concentration of the paint 2 in the coater pan 3 is provided, and the densitometer 14 outputs the detected density information to the adhesion amount control unit 15. Although FIG. 1 illustrates the case where the densitometer 14 is arranged in the circulation path, of course, the concentration of the paint 2 in the coater pan 3 may be directly detected. As the densitometer 14 for measuring the concentration of the paint 2, the amount of the substance may be directly measured, or a physical property value or the like having a large change according to the concentration change may be used. For example, a refractometer, a viscometer, a hydrometer, a spectrophotometer, or the like can be used, and a suitable measuring device may be selected depending on the type of the paint 2. Further, the relationship between these measured values and the concentration of the paint 2 may be calibrated in advance, and is not particularly limited.

As shown in FIG. 2, the adhesion amount control unit 15 includes a wet adhesion amount determination unit 15A and an adhesion amount adjustment unit 15B.
The wet adhesion amount determination unit 15A obtains a wet adhesion amount Dw that is an adhesion amount before drying, based on the acquired adhesion amount Dd after drying and the concentration C of the paint 2. The wet adhesion amount determination unit 15A constitutes a wet adhesion amount detection unit.
For example, when the film thickness is selected as the adhesion amount Dd and the wet adhesion amount Dw after drying, the wet adhesion amount Dw is obtained from the adhesion amount Dd after drying by the following equation, for example.
Dw = Dd ÷ C × K1
Here, K1 is a proportional coefficient according to the specific gravity of the paint 2.
Moreover, you may use the adhesion mass of the coating material 2 per unit area. In this case, correction by specific gravity is unnecessary.

The target dry adhesion amount range (target dry adhesion amount range) of the dry adhesion amount Dd and the target wet adhesion amount range of wet adhesion amount Dw (range of target pre-drying adhesion amount) are input in advance to the adhesion amount adjusting unit 15B. Is done.
Here, the upper and lower limit values of the target dry adhesion amount range are set from the viewpoints of corrosion resistance, workability, and insulation required for the object 1 to be coated. On the other hand, the upper and lower limits of the target wet adhesion amount range are values obtained from experiments and empirical values irrespective of the target dry adhesion amount, and are necessary for obtaining a good coating appearance without causing coating defects. It is set within the range of the adhesion amount in the wet state.

  Then, the adhesion amount adjusting unit 15B sets the acquired dry adhesion amount Dd to be an adhesion amount that falls within the target dry adhesion amount range, and the calculated wet adhesion amount Dw becomes an adhesion amount that falls within the target wet adhesion amount range. In addition, by adjusting the roll peripheral speed, the nip pressure between the rolls, the gap between the rolls, or the concentration of the coating material 2, the amount of coating applied is adjusted.

  For example, as shown in FIG. 3, a dead zone is set in the central region of the target dry adhesion amount range, and the current dry adhesion amount Dd is located within the dead zone. As shown in FIG. 4, based on, for example, a deviation Δw between the median value Pw and the current wet adhesion amount Dw within the target wet adhesion amount range, the circumferential speed of the roll or between the rolls in the direction in which the deviation Δw decreases. Adjust the nip pressure or the gap between rolls. On the other hand, when the current dry adhesion amount Dd is located outside the dead zone, the deviation Δd is based on, for example, the deviation Δd between the median value Pd within the target dry adhesion amount range and the current dry adhesion amount Dd. The roll peripheral speed, the nip pressure between rolls, or the gap between rolls is adjusted in the decreasing direction.

As another example of the control of the adhesion amount adjusting unit 15B, a deviation Δw between, for example, the median value Pw within the target wet adhesion amount range and the current wet adhesion amount Dw, and, for example, the median value Pd within the target dry adhesion amount range. And the current dry adhesion amount Dd based on the ratio (Δw / Δd) to the deviation Δd, etc., the roll peripheral speed in the direction where the deviation Δw or Δd on the side where the deviation from the median is larger becomes smaller, or between the rolls Adjust the nip pressure or the gap between rolls.
Further, when it is determined that the dry adhesion amount Dd and the wet adhesion amount Dw are not compatible at the roll peripheral speed, the nip pressure between the rolls, and the gap between the rolls, the dry adhesion amount is adjusted by adjusting the concentration of the paint 2. Dd and wet adhesion amount Dw are kept within the target values.

(Function and effect)
For example, even if the dry adhesion amount Dd is within the target dry adhesion amount range, the liquid between the rolls or between the applicator roll 6 and the object to be coated 1 in the state where the concentration of the paint 2 is low and the wet adhesion amount Dw is excessive. The pool portion is likely to vibrate due to the influence of rotation of the roll and the like, and coating defects are likely to occur. Since the adjustment of the density is not responsive, there is a possibility that a coating defect may occur even if feedback control is performed so that the dry adhesion amount Dd becomes the target value.

On the other hand, in the present embodiment, the wet deposition amount Dw is also obtained from the viewpoint of coating appearance while adjusting the coating conditions so that the dry deposition amount Dd is within the target dry deposition amount range determined from corrosion resistance and the like. As a result of adjusting the application conditions so as to be within the target wet adhesion amount range, it is possible to satisfy the required requirements such as corrosion resistance and insulation and to make the application appearance good.
(application)
Here, although the case where automatic adjustment is illustrated in the above embodiment, the roll peripheral speed, the nip pressure between rolls, and the gap between rolls may be adjusted by an operator.

Using the equipment described in the above embodiment, a water-based paint 2 having a viscosity of 1 cp and a surface tension of 40 dyn / cm at a liquid temperature of 25 ° C. is applied to a coil of a galvanized steel sheet as the object 1 did. A saccharimeter using refractive index measurement was used as the densitometer 14, and the supply of dilution water was controlled so that the management range of saccharities was in the range of 2.50 to 2.80. The wet adhesion amount Dw is calculated from the adhesion amount measured by the sugar content meter and the adhesion amount meter 11, and the target wet adhesion amount range of the adhesion amount is within a predetermined wet adhesion amount range of 6.5 to 8.5 μm. Feedback control was performed to change the applicator roll 6 peripheral speed so as to be inside.
As a comparative example, the concentration of the paint 2 is measured offline, which is a conventional method, the operator adjusts it so that it is within the concentration management range of the paint 2, and the conditions such as the roll peripheral speed are set so that the adhesion amount is within the management range. Set and apply. The concentration adjustment of the paint 2 was performed by the operator before it seemed that it would be out of the control range of the amount of adhesion even if the roll peripheral speed or the like was changed.

In the examples, while being always within the management range of the adhesion amount and controlling the wet adhesion amount Dw, the coating appearance is good and stable quality is obtained, whereas in the comparative example, Although it was within the target dry adhesion amount range of the dry adhesion amount Dd, there may be a coating defect caused by the increase in the wet adhesion amount Dw, and stable quality could not always be maintained. Further, in the comparative example, the concentration adjustment of the paint 2 and the change of the roll peripheral speed cannot be performed without the intervention of the operator, whereas in the example, all can be automatically controlled during the operation, so that labor saving is possible. .
In addition, although the steel plate was used as a to-be-coated body in the said Example, it is not limited to a steel plate in particular, It applies to other metal plates, such as aluminum, paper, and a film.

It is a schematic diagram which shows the installation structure which concerns on embodiment based on this invention. It is a figure which shows the structural example of an adhesion amount control part. It is a figure explaining the dry adhesion amount. It is a figure explaining the amount of wet adhesion.

Explanation of symbols

1 Coated body 2 Paint 3 Coater pan (coating container)
6 Applicator Roll 11 Adhesion Meter 14 Densitometer 15 Adhesion Amount Control Unit 15A Wet Adhesion Amount Determination Unit 15B Adhesion Amount Adjustment Unit 16 Diluent 17 Dilution Tank Dd Dry Adhesion Amount Dw Wet Adhesion Amount

Claims (3)

The applicator roll is used to apply and apply the paint in the paint container to the surface of the object to be continuously conveyed by transfer, and the paint applied to the object surface is attached after drying. In the continuous coating treatment method for adjusting the coating amount to adhere so that the amount is within the range of the target dry deposition amount,
The adhesion amount after the drying is within the range of the target dry adhesion amount, and the adhesion amount before drying of the paint applied to the surface of the object to be coated is within the preset target adhesion amount range before the drying. A continuous coating treatment method, wherein the coating amount is adjusted. The paint in the coating container is transferred to the applicator roll, and the paint transferred to the applicator roll is transferred to the surface of the object to be continuously conveyed, thereby applying the paint to the object to be coated. In continuous coating treatment equipment that performs
A dry adhesion amount detection means for detecting an adhesion amount after drying of the paint applied to the surface of the object to be coated; a wet adhesion amount detection means for detecting an adhesion amount of the paint applied to the surface of the object to be coated before drying;
Based on the detection information of the dry adhesion amount detection means and the wet adhesion amount detection means, the adhesion amount after drying falls within the predetermined target dry adhesion amount range, and the adhesion amount before drying falls within the target drying amount range. And adjusting means for adjusting at least one of the transfer amount of the paint to the applicator roll, the peripheral speed of the applicator roll, the gap between the applicator roll and the object to be coated, and the concentration of the paint. Application processing equipment.   3. The continuous coating process according to claim 2, wherein the wet adhesion amount detection means obtains the adhesion amount before drying from the adhesion amount after drying detected by the dry adhesion amount detection means and the concentration of the paint. Facility.

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