JPH01189366A - Controller for roll coater - Google Patents

Abstract

PURPOSE:To obtain a coating having uniform thickness by supplying a paint into the gap formed by a doctor roll and a coating roll from a paint feeder, detecting the amt. of the paint supplied with a sensor, and keeping the amt. at a practically constant value. CONSTITUTION:The doctor roll 10, the coating roll 11, and a backup roll 12 are provided in the roll coater 1. A paint is supplied into the gap 14 formed by the rollers 10 and 11 from the paint feeder 2. The amt. of paint stored in the gap 14 is detected by the sensor 3. The amt. of paint to be supplied from the feeder 2 is controlled by the control part 4 in accordance with the signal from the sensor 3, and the amt. of paint stored in the gap 14 can be kept at a practically constant value. As a result, a paste dish is dispensed with, the frequency of changing stages can be reduced, and coating can be carried out in uniform thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for coating with a uniform thickness in roll coater coating. The present invention is useful when painting with a paint having a short pot life.

[Prior Art] Reverse roll coater painting is known as an example of mechanical painting. This reverse roll coater coating allows easy control of coating film thickness and is widely used in various fields.

For example, the surfaces of automobile weather strips and the like have recently been coated with urethane paint. This coating is generally performed using a reverse roll coater as shown in FIG. This conventional reverse roll coater paint machine includes a doctor roll 100, a coating roll 101, and a backup roll 102. The doctor roll 100 is located within the regulator 103, and coating N104 is placed inside the regulator 103.

In this reverse roll coater painting machine, paint 104 is applied to the doctor roll 100 by rotation of the doctor roll 100.
The image is transferred onto the coating roll 101 and transferred onto the coating roll 101. Note that the amount of paint that adheres to the circumferential surface of the coating roll 101 is controlled by the clearance between the doctor roll 100 and the coating roll 101. Then, at the same time as the object to be coated 200 is fed by the backup roll 102, the coating roll 101
The paint adhering to the surface is applied to the surface of the object 200.

The paint overflowing from both sides of the coating roll 101 is collected into the control device 103 by a side doctor 105.

[Problems to be Solved by the Invention] However, due to the performance of the coating film, the paint applied to the surface of Uninar Strip etc. is not usable, for example, the viscosity increases to the point that it cannot be painted after 20 minutes at 25°C. A two-component reaction curing type (urethane) paint is used, which takes an extremely short time.

Therefore, the paint in the control device must be used up within its pot life. However, since the area to be painted with weather strips etc. is extremely small, the amount of paint used is approximately 40cc per minute.
The following are extremely rare. Therefore, a problem arises in that the viscosity of the paint in the control device gradually increases, and the thickness of the coated film gradually increases. In addition, for urethane resin paints,
Reactions between the isocyanate used and moisture in the air also occur, resulting in poor coating performance.

Therefore, it is possible to reduce the opening area of the regulator to reduce its volume, reduce the contact area between the paint and air, and frequently supply new paint into the regulator to suppress the increase in viscosity. However, in this case, the number of changes in paint supply increases, which increases the number of man-hours.

The present invention has been made in view of the above problems, and
The present invention provides a roll coater coating control device that eliminates the need for a controller, reduces the number of setup changes, and can coat a film with uniform thickness.

[Means for Solving the Problems] The roll coater coating control device of the present invention includes a roll coater coating machine equipped with a doctor roll, a coating roll, and a backup roll, and a doctor roll and a coating roll of Roll Coater Coating i HJI. A paint supply device that supplies paint to the gap formed, a sensor that detects the amount of paint stored in the gap, and a control that controls the amount of paint supplied by the paint supply device in accordance with a signal from the sensor. It is characterized in that the amount of paint stored in the gap can be maintained at a substantially constant amount.

A conventional roll coater can be used, and either a natural roll coater or a reverse roll coater can be used.

The paint supply device is a device that supplies paint to the gap formed between the doctor roll and the coating roll. The thickness of the film applied to the object to be coated can be regulated by the clearance of this gap.

When paint is supplied to this gap, the paint is smoothly supplied to the surface of the coating roll by the rotation of the coating roll and doctor roll, making it possible to paint.

Note that it is desirable that the amount of paint supplied to this gap be kept to the minimum necessary, preferably to the same level as the amount to be painted. When the amount of paint increases, the rate of reaction with moisture in the air increases in the case of urethane paints, and the amount of solvent volatilized increases in the case of solvent-based paints. Therefore, various conventional means such as pumps can be used as the paint supply device, but it is preferable to use a device that can finely adjust the amount of paint supplied. For example, as shown in the examples below, a sealed container containing paint, a supply pipe that supplies the paint from the container to the gap,
It is preferable to use a device comprising a pressure variable device that varies the pressure inside the container within a range of 0.1 to 0.2 kg/cm 2 . In this way, the amount of paint supplied from the supply pipe can be controlled to 55 CC/min or less using the pressure variable device, making it possible to finely adjust the supply ω. In addition, in the case of a paint supply device having such a container, it is preferable that the container is provided with a temperature control device for adjusting the temperature of the paint inside. This temperature control device can be a cooling pipe or the like through which cooling water flows. In this way, the viscosity of the paint contained in the container can be kept constant, and fluctuations in the supply amount can be suppressed. In addition, by setting the temperature control temperature low, the reaction rate can be reduced, and the pot life is increased, so the number of stage changes can be reduced.

In the case of a two-component paint, it is possible to prepare two containers, put gold waves in each container, mix them with a static mixer, etc. immediately before the gap, and supply the mixture.

In this way, there is no need to worry about pot life, and there is no need to change parts.

The sensor has the function of detecting the amount of paint stored in the gap. Although various conventionally known sensors can be used as this sensor, it is preferable to use a non-contact displacement meter. In this way, the trouble of cleaning the sensor, etc. can be saved, and the amount of paint can be easily detected based on the height of the liquid level.

The control section controls the supply period of the paint supply device according to the signal from the sensor. This control section can be formed using various conventionally known digital circuits.

"Actions and Effects of the Invention" In the roll coater painting control device of the present invention, 1 ton of paint is supplied.
tt supplies the paint to the gap formed between the doctor roll and the coating roll. The amount of paint stored in the gap is then detected by a sensor. Here, if the amount of paint is less than a predetermined amount, the control unit controls the paint supply device to increase the supply amount. Further, when the sensor detects that the amount of paint in the gap exceeds a predetermined amount, the controller controls the paint supply device to reduce the amount of paint supplied. As a result, the amount of paint stored in the gap is controlled to be approximately constant a.

In other words, according to the roll coater coating control device of the present invention,
Since there is no need to use a width gauge as in the past, thickening of the paint inside the gauge, reaction with moisture in the air on the surface of the gauge, and continuous failure of the solvent can be prevented. Furthermore, since it is possible to supply an amount of paint close to that of the seedlings to be painted, the residence time of the paint in the gap can be extremely shortened. These actions can suppress an increase in the viscosity of the paint, allowing it to be coated with a uniform film thickness.

Furthermore, if the temperature of the paint container in the paint supply device is cooled to a low temperature, or if two containers are used to supply the paint, the number of changeovers can be significantly reduced.

[Example] This will be explained in detail below using examples.

FIG. 1 shows a roll coater coating control device according to an embodiment of the present invention. This control fi 11 device includes a reverse roll coater coating machine 1, a paint supply device 2, a sensor 3, and a control section 4.
It consists of

As shown in FIG. 2, the reverse roll coater coating machine 1 includes a doctor roll 10, a coating roll 11,
Backup role 12 and a pair of side doctors 13
It consists of The coating roll 11 and the backup roll 12 are rotating in the same direction, and the doctor roll 10 is rotating in the opposite direction to the coating roll 11 and the backup roll 12. The backup roll 12 has the function of conveying the weather strip 5 (hereinafter referred to as a work), and is usually coated with rubber. The coating roll 11 is usually made of metal such as stainless steel, and has the function of transferring paint onto the surface of the workpiece 5. The thickness of the paint adhering to the surface of the coating roll 11 is determined by the clearance of the gap 14 formed between the doctor roll 10 and the coating roll 11, and the thickness of the paint is transferred onto the workpiece 5. Note that the side doctor 13 is urged toward each other by a spring 15 and is pressed against the end surfaces of the doctor roll 10 and the coating roll 11, thereby preventing paint from leaking from the gap 14.

The paint supply device 2 includes a heat retention tank 2 having a temperature control jacket 21.
0, a polyethylene tank 22 placed in the heat retention tank 20, and a supply pipe 23 extending from the tank 22 to the gap 14.
and a pressure vR24 communicating with the tank 22 and supplying pressurized air into the tank 22. pressure tube 24
is supplied with air from a compressor 26 via a precision regulator 27 and a solenoid valve 28. Also, inside the tank 22 is a two-component reaction-curing urethane resin W1 paint 25.
is filled. The darkness of the paint supplied from the supply pipe 23 to the gap 14 can be varied by the pressure of pressurized air supplied from the pressure pipe 24.

By the way, the precision regulator 27 lowers the pressure inside the tank 5 to 0.
．． 1 to 0.2 to 9/c1 (D pressure internal variable, supply pipe 2
3 to the gap 14 at a rate of 55 cc or less per minute. The adjustment range is 0゜02kll/C
The sensor 3 is composed of a non-contact displacement meter, and detects the height of the paint level in the gap 14 by reflecting light.

The control unit 4 receives the signal from the sensor 3 and controls the paint supply amount W2.
The solenoid valve 28 and precision regulator 27 of ill a
It has the function of ll, and is composed of a digital circuit using a microcomputer or the like.

A method of using the roll coater coating control device of this embodiment configured as described above will be described below.

Urethane paint with a viscosity of 200 cps (20°C) is stored in the tank, and the temperature is adjusted to 25°C by the temperature control jack ↑rket 21.
has been adjusted to. Pressurized air at a constant pressure of 0.12 kp/cm2 (1) is supplied from the pressure pipe 24 into the tank 22 by the precision regulator 27, and the inner diameter is 6 mm.
The gap portion 14 is supplied from the supply pipe 23 at a supply rate of 35 cc/min.
paint is supplied to. Approximately 200 C of paint is present in the gap 14. And backup roll 1
2 conveys the workpiece 5, and a coating roll 11 applies paint to the workpiece 5 with a predetermined film thickness.

However, due to reasons such as clogging of the supply pipe 23, the gap 14
When the amount of paint supplied to the gap 14 decreases, the liquid level in the gap 14 decreases. Then, the sensor 3 detects that the liquid level has decreased and sends a signal to the control section 4. The control unit 4 then controls the precision regulator 27 of the paint supply device 2 to increase the pressure inside the tank 22 and increase the amount of paint supplied.

On the other hand, if the supply amount increases for some reason and the liquid level in the gap 14 becomes high, the control unit 4 turns off the solenoid valve 28 for a certain period of time based on the signal from the sensor 3 to lower the tank 22 pressure. (As a result, the amount of paint supplied from the supply pipe 23 decreases, and the height of the liquid level decreases.The precision regulator 27 controls the pressure inside the tank 22 with a width of 0.02 kQ/c1. At this time, the supply amount from the supply pipe 23 is increased to 111II at a rate of 5 cc/min.

In other words, according to the roll coater painting system of this embodiment, the paint placed in the tank 22 is transferred to the temperature control jacket 21.
Since the temperature is controlled at about 25° C. even in summer, the pot life is extended and the viscosity of the paint supplied from the supply pipe 23 can be maintained constant. This allows the number of stage changes to be reduced. Further, the paint supply device 2 can be minutely adjusted and can supply a small amount of paint to the gap 14. Therefore, the necessary minimum amount of paint is always present in the gap 14 and is quickly used, so thickening can be prevented. Thereby, the workpiece 5 can always be coated with a uniform film thickness. By the way, conventionally the film thickness varied from 30μ to 110μ within 1 hour, but according to the roll coater coating control device of this embodiment, the variation in film thickness varies from 30μ to 110μ within 4 hours.
The variation was extremely small, ranging from 5μ to 45μ.

[Brief explanation of the drawing]

FIGS. 1 and 2 relate to a roll coater coating control device according to an embodiment of the present invention, with FIG. 1 being an explanatory diagram of the overall configuration thereof, and FIG. 2 being an enlarged perspective view of essential parts of the roll coater painting machine. FIG. 3 is a perspective view of the main parts of a conventional reverse roll coater coating machine. 1... Reverse roll coater coating machine 2... Paint supply device 3... Sensor 4... Control WJ device 5... Workpiece 10... Doctor [1-ru 11... Coating roll 12... ...Backup roll 13...Side doctor 14...Gap 22...Tank 26...
・Compressor 27...Precision regulator 28...Solenoid valve Fig. 1/-

Claims (1)

[Claims] (1) A roll coater paint machine including a doctor roll, a coating roll, and a backup roll; a paint supply device that supplies paint to a gap formed by the doctor roll and the coating roll of the roll coater paint machine; , a sensor that detects the amount of the paint stored in the gap, and a control unit that controls the amount of paint supplied by the paint supply device in accordance with a signal from the sensor; A roll coater coating control device characterized in that the amount of paint can be maintained at a substantially constant amount.