JPH06210238A - Coating method using a roll coater type coating device - Google Patents

Abstract

(57) [Summary] [Objective] To establish a means for stably forming a coating film having a uniform film thickness in the width direction by using a roll coater type coating device. [Structure] When coating with a roll coater type coating device,
Between the pickup roll 1 and the applicator roll 2, between the backup roll 3 and the applicator roll 2, or a separate paint adhesion amount control roll (metering roll, doctor roll). Roll roller, etc.) and the amount of pressing force between the roll and the roll that it is in contact with can be independently controlled at both ends of the roll shaft.
A roll type coating device is used, and the distance between rolls formed on the coating film formed on the applicator roll 2 or the strip-shaped coating material 6 is measured online with a distance meter 8 or the like, and the roll is measured. The pressing amount between the rolls is independently finely adjusted at both ends of the roll shaft in accordance with the difference in the eye spacing near both ends of the roll.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous coating method for applying a uniform coating film of a coating material (including a functional material etc.) to a strip-shaped coating material such as a steel plate using a roll coater type coating device. It relates to the coating method.

[0002]

2. Description of the Related Art Conventionally, a roll coater type coating apparatus has been widely used for continuous coating of strip-shaped materials such as steel plates, synthetic resin films and papers. For example, Japanese Patent Publication No. 60-56552 shows a typical example of this roll coater type coating apparatus. The apparatus is, as schematically shown in FIG. 7, a pickup roll 1 and an applicator. It has a tawl roll 2 and a backup roll 3, and the paint 5 in the paint pan 4 attached to the rotating pickup roll 1 is transferred to the applicator roll 2 and further backed up roll. It is configured to be applied to the belt-shaped object to be coated 5 that is wound around 3. There is also known a device in which a metering roll, a doctor roll or the like is attached to an applicator roll or the like in order to control the adhesion amount of the coating film.

By the way, in continuous coating by such a roll coater, due to the imbalance of the pressing amount at the bearing portions at both ends of the roll, the material width is often applied to the coating film formed on the strip-shaped material to be coated. There was a tendency to cause a difference in film thickness in the direction.

For this reason, film thickness meters (infrared, γ
"Line thickness gauge" is used to measure the "thickness difference in the plate width direction" of the coating film formed on the strip-shaped coating material online, and the pressure is applied to the bearings at both ends of the roll according to this measurement result. Adjust the amount or visually observe the dispersion of the coating amount on the roll by the operator, and based on this, finely adjust the pressing amount of the roll so that the coating amount becomes uniform. Therefore, attempts have been made to maintain the uniformity of the coating film thickness in the material width direction.

However, in the method of measuring the non-uniformity of the coating film thickness by the film thickness meter, it is necessary to correct the film thickness meter for each kind of paint, and in the case of small lot production of a large number of products. It was pointed out that the maintenance required a lot of work. Further, in the method of monitoring the unevenness of the coating film thickness by visual inspection of the operator, it is very inefficient because manpower is required every time the operating conditions change, and extremely high skill is required for the operator. There was a problem with being.

In view of the above, the object of the present invention is that the amount of pressing between the rolls becomes unbalanced at both ends of the roll during coating by the roll coater type coating device. Stable and stable coating material with a uniform coating thickness, by simply and accurately detecting the "unevenness of coating film thickness in the width direction of the coating material" that occurs, without requiring special labor or skillful operators. To provide a manufacturable means.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the inventors of the present invention have found that "it is often temporary when coating is performed by a roll coater type coating device". A ridge pattern called "roll" that is parallel to the width direction of the coating material is generated on the surface of the coating film. The interval of the rolls in the width direction of the coating material is the change in the coating film thickness in that direction. It is possible to accurately grasp the variation of the coating film thickness in the width direction of the material to be coated by "measuring the distance between rolls". By adjusting the pressing amount of each of them independently at both ends of the roll shaft to make them uniform, the unevenness of the coating film thickness in the width direction can be appropriately and easily corrected. I was able to.

The present invention has been completed based on the above findings and the like, "When coating with a roll coater type coating device, between the pickup roll and the applicator roll, the backup roll is used. The amount of pressing between the roll and the applicator roll, or between the separately installed paint adhesion control roll (metering roll, doctor roll, etc.) and the roll in contact with it, is set at both ends of the roll shaft. Using a roll coater type coating device of a type that can be independently controlled by the control section, and online measuring the spacing between rolls formed on the paint roll formed on the applicator roll or strip-shaped coating material. Then, the applied amount between the rolls is finely adjusted independently at both ends of the roll shaft according to the difference in the roll spacing near the both ends of the roll. Is that it enables stable manufacturing of coating materials that are uniform in the width direction. " It has a butterfly.

As described above, in the present invention, the pressing amount between the backup roll and the applicator roll or between the pickup roll and the applicator roll can be controlled independently at both ends of the roll shaft. Type roll coater type coating device or a metering roller for controlling the amount of paint film adhered.
A multi-roll type roll coater equipped with a roll, a doctor roll or the like, and the pressing amount of the roll contacting the roll can be independently controlled at both ends of the roll shaft. A mold coating device is used, and such a roll coater type coating device itself is conventionally known as described above.

However, the present invention is characterized by the use of the roll coater type coating device of the above-mentioned type and the "coating material formed on the material to be coated (steel plate or the like) or the applicator roll. Online the distance between rolls generated on the membrane
By measuring at multiple points or at multiple points, the difference in the roll spacing near both ends of the roll is detected, and the pressing amount between the rolls is determined at each roll end according to the difference. The point is that fine adjustments were separately made to correct the non-uniformity of the roll pressing amount and to make the coating film uniform. The reason why the coating film in the width direction of the material to be coated is made uniform by such a method is as follows.

[0011]

That is, as described above, when the belt-shaped coating material is continuously coated by the roll coater type coating apparatus, the portion A (applicator roll 2 and pickup roll 1 in FIG. 1 is coated. Between)
In this case, due to instability of paint flow, ridge-like irregularities called "roll eyes" occur. Incidentally, in the roll coater type coating apparatus additionally provided with the metering roll 7 as shown in FIG. 2, the part B (applicator roll 2 and the metering roll) is used.
Similar irregularities (roll eyes) occur between the rolls 7.

FIG. 3 is a schematic diagram of the above-mentioned "roll eyes". These roll eyes have the same intervals under the same conditions, and the intervals are governed by the following mathematical formulas.

[0013]

[Equation 1]

Therefore, when coating is carried out at a certain line speed and roll peripheral speed ratio, the average value U of roll peripheral speed, the average value R of roll radius, the viscosity of paint, the surface tension σ of paint. If does not change, then at some point
The change in the roll spacing λ in the roll width direction is determined by the minimum gap h ₀ between the rolls.

In other words, if there is a difference in the roll spacing between the two end positions of the roll, this difference occurs because the amount of pressing the roll is unbalanced at both end positions of the roll. The degree of the difference corresponds to the minimum gap h ₀ between the rolls at the position (that is, the roll pressing amount).

Therefore, by detecting the "difference in roll eye gaps at both ends of the roll", "the imbalance of the roll pressing amount at both ends of the roll" can be accurately detected. . Then, depending on this difference, if the amount of roll pressing at the end of the roll shaft is finely adjusted independently of both ends to eliminate the imbalance, the minimum gap h ₀ between the rolls is in the width direction of the roll. It is made uniform, and the unevenness of the coating film thickness in the width direction of the material to be coated is corrected. It should be noted that "roll eyes" generated in the coating film
Has a leveling effect due to the surface tension of the paint and is hardly noticeable before drying and baking. However, in some cases, measures for strengthening the leveling effect (such as maintaining low temperature in the drying and baking furnace) are taken.

Hereinafter, the present invention will be described more specifically by way of examples.

【Example】

<Embodiment 1> As shown in FIG. 1, a pickup roll 1 (diameter 300 mm), an applicator roll 2 (diameter 25)
In a roll coater type coating apparatus comprising a 0 mm steel roll with a 20 mm thick rubber lining) and a backup roll 3 (700 mm), an applicator roll 2 or a strip-shaped coating is used. Coating material 6 (1000m wide in this example)
m, using a 0.5 mm thick plated steel plate),
A non-contact type distance meter 8 (in this example, a laser distance meter is used) for measuring the roll distance generated in the paint film is installed, and a control system as shown in FIG. 4 is constructed. .

In this control system, first, the distance meter 8 installed above the applicator roll 2 or the plated steel plate is scanned at both ends of the roll in the direction of the roll axis to determine the roll eye distance. The measurement is performed, and the calculator 9 obtains the "deviation of the roll gap" at both ends of the roll with reference to the average value of the gap in the width direction. Then, in response to this, the computer 9 independently operates the roll support base driving motor 11 installed on the roll support base 10 of the pickup roll 1 so that the pickup roll 1 and the application roll can be operated. -The pressing amount between the rolls 2 is controlled, and the pressing amount balance in the roll axial direction (the minimum gap between the rolls in the roll axial direction) is adjusted. Note that FIG.
Reference numeral 12 in the figure indicates a pickup roll driving motor.

Now, using the above-mentioned roll coater type coating device, a high molecular polyester paint (viscosity: 1.0 Pa · s, surface tension: 3) is applied to a plated steel plate (width: 1000 mm, thickness: 0.5 mm).
0 dyn / cm) continuous coating test was carried out. In this case, the roll peripheral speed ratio is constant and the line speed condition is shown in Table 1.
As shown in FIG. The distance between the rolls was measured by the distance meter 8 at either the upper position of the applicator roll 2 or the upper position of the plated steel plate.

[0020]

[Table 1]

Then, the coating film thickness control was carried out according to the correction curve shown in FIG. 5 while measuring the roll-to-roll spacing online, and as a result, as shown in Table 1, the conventional (film from the roll-to-roll) The variation of the film thickness at the both ends of the steel sheet was about 5 to 6% (without thickness control), but was suppressed to about 2% or less.

<Embodiment 2> As shown in FIG. 2, pickup roll 1 (diameter 300 mm), applicator roll 2 (steel roll 250 mm in diameter, 20 mm thick rubber lining) ), Metering roll 7 (diameter 150 mm
Steel roll) and backup roll 3 (700 m
m) in a roll coater type coating device, above the applicator roll 2 or the strip-shaped coated material 6 (also in this example, a plated steel sheet having a width of 1000 mm and a thickness of 0.5 mm) is used. A non-contact type distance meter 8 (a laser distance meter is also used in this example) for measuring the roll-to-roll distance generated in the paint film is installed at the position. -Taro-
A control system was constructed so as to adjust the pressing amount of the metering roll 7 against the rule 2.

Also in this control system, first, the distance meter 8 installed at the upper position on the downstream side of the metering roll of the applicator roll 2 or on the upper position of the plated steel plate is in the axial direction of the roll at both end positions of the roll. Scan to measure the roll spacing,
A computer calculates the "roller gap deviation" at both ends of the roll with reference to the average value of the gap in the width direction. Then, in response to this, the motor for driving the roll support base of the metering roll 7 is operated to control the amount of pressing between the metering roll 7 and the applicator roll 2 to make the roll. Finely adjust the balance of pressing amount in the axial direction.

Now, using the above roll coater type coating apparatus, a high molecular polyester coating (viscosity: 1.0 Pa.s, surface tension: 3) is applied to a plated steel plate (width: 1000 mm, thickness: 0.5 mm).
0 dyn / cm) continuous coating test was carried out. Also in this case, the roll peripheral speed ratio was kept constant, and the line speed conditions were changed in four ways as shown in Table 2. The distance between the rolls was measured by the distance meter 8 either above the applier roll 2 or downstream of the metering roll or above the plated steel plate.

[0025]

[Table 2]

Table 2 also shows the results obtained by finely adjusting the pressing amount of the metering roll according to the correction curve shown in FIG. As described above, the variation of the film thickness at the both ends of the steel sheet was suppressed to 2% or less, which was about 5% in the related art (without controlling the film thickness from the roll eye).

[0027]

[Summary of Effects] As described above, according to the present invention, it is possible to easily and stably suppress the unevenness of the coating film thickness in the plate width direction, which tends to occur in the coating using the roll coater type coating device. It is possible to achieve the above, and it is possible to bring about useful effects in industry, such as making a great contribution to improving the performance of coating materials.

[Brief description of drawings]

FIG. 1 is an explanatory view of a roll coater coating method according to the present invention.

FIG. 2 is an explanatory diagram related to another example of the roll coater coating method according to the present invention.

FIG. 3 is a schematic view of a roll eye.

FIG. 4 is a block diagram showing an example of a “control system for a roll coater type coating apparatus” according to the present invention.

FIG. 5 is a schematic diagram of “a graph showing the relationship between the line speed, the roll gap and the coating film thickness” used for controlling the roll coater type coating apparatus in the examples.

FIG. 6 is a schematic view of another example of “a graph showing the relationship between the line speed, the roll gap and the coating film thickness” used for controlling the roll coater type coating apparatus in the examples.

FIG. 7 is a schematic explanatory view of a roll coater type coating device.

[Explanation of symbols]

 1 Pick-up roll 2 Applicator roll 3 Backup roll 4 Paint pan 5 Paint 6 Strip-shaped coated material 7 Metering roll 8 Distance meter 9 Calculator 10 Pickup roll support stand 11 Pickup roll Motor for driving the roll support base of the roll 12 Motor for driving the pickup roll

Claims (1)

[Claims] 1. A pickup roll and an applicator roll.
Between the rolls, between the backup rolls and the applicator rolls, or between the rolls for controlling the amount of paint adhered separately and the rolls that are in contact with the paint rolls can be independently controlled at both ends of the roll shaft. While using the roll coater type coating apparatus of No. 1, the spacing between rolls formed on the paint roll formed on the applicator roll or the strip-shaped coating material is measured online, and the spacing between the rolls is measured. The roll coater type coating apparatus is characterized in that the pressing amount between the rolls is finely adjusted independently at both ends of the roll shaft according to the difference in the vicinity of both ends of the roll. How to paint.