JPS63229170A - Coating system - Google Patents

Abstract

PURPOSE:To achieve the miniaturization of the title system and high speed continuous operation and to form a coating film having good quality, in a defoaming treatment apparatus, by allowing paint to be treated to flow down in a curtain form to increase the surface area and reducing its pressure to apply defoaming treatment to the paint in a membrane state. CONSTITUTION:A defoaming treatment apparatus 4 is evacuated to be reduced to desired atmospheric pressure and, after the opening degrees of valves 20a, 20c are appropriately set, a pressure feed pump 20b is operated to introduce the new paint in a paint tank 2 into an upper chamber 14 from piping 20. This paint to be treated passes through a slit-like through-hole plate on the way to fall in a lower chamber 16 and, at this time, the paint becomes the membrane form corresponding to the arrangement pattern of slits and the surface area of the paint is sufficiently enlarged to fall in the lower chamber 16 while the tinning of the paint is promoted. Therefore, the air bubbles in the paint to be treated are rapidly and easily broken under reduced pressure to discharge air and the defoamed paint is accumulated in the lower part of a container before supply to the flow coater head 16 of a painting apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coating system, and particularly to a coating system in which defoamed paint is supplied to a coating device.

[Prior Art] It is widely practiced to machine metal plates by cutting, drilling, bending, etc. into components of desired shapes and dimensions for various types of equipment.

Many of these parts are painted for reasons such as appearance or to prevent rust.

Conventionally, such metal parts have been painted after the material metal plate has been machined into a predetermined shape and size.

However, since the metal parts after machining generally have a complicated three-dimensional shape, painting work is extremely troublesome, and there is also a lot of wasted paint, causing an increase in manufacturing costs.

Therefore, in recent years, it has become common to manufacture metal plates whose entire surfaces are coated in advance (pre-coated metal: PCM) and to manufacture parts by machining the PCM. According to this, PCM manufacturing can apply high-quality coating uniformly to the entire surface with less paint waste, so the process can be shortened even from the perspective of manufacturing a single part as a whole, and labor and resource conservation can be achieved. Can be done.

When producing PCM as described above, curtain flow coater coating and roll coater coating are preferred, which have high coating efficiency and can form a coating film continuously at high speed.

By the way, paints generally have a high viscosity and often contain air bubbles during the manufacturing process. If a paint containing air bubbles is used for painting, pinholes may occur in the formed coating film, or curtain damage may occur. When painting with a flow coater, curtain breakage occurs and stable and good painting cannot be achieved.For this reason, a defoaming process is required to remove air bubbles from the paint prior to painting.

This type of defoaming treatment is generally carried out by reducing the pressure in the sealed container containing the paint, causing the air bubbles in the paint to expand and float to the free surface, then crushing the floating bubble film and releasing it into the air. .

However, since the viscosity of the paint is quite high, simple depressurization treatment as described above cannot achieve sufficient defoaming treatment in a short time.
Because of this, fast! 1! It becomes difficult to supply a sufficient amount of degassed paint to be used in the coating equipment where coating is carried out. Therefore, conventionally, in order to increase the speed of vacuum degassing treatment, for example, (1) the paint to be treated is forcibly stirred,
(2) Creating high-speed eddy currents in the paint to be treated; and (3) Transmitting ultrasonic waves to the paint to be treated.

[Problems to be Solved by the Invention] However, in the case of defoaming treatment that adopts the acceleration method described in (1) above, the defoaming treatment speed cannot be sufficiently shortened, and furthermore, since it is a batch process, continuous processing is required. In the case of defoaming treatment that adopts the acceleration method described in (2) above, solids such as pigments tend to separate due to the centrifugal force of the eddy current, and furthermore, continuous processing is difficult. In the case of defoaming treatment using this method, solids such as pigments tend to aggregate due to the action of overlapping waves, making continuous treatment difficult. Furthermore, each of the above-mentioned means also had problems such as low efficiency of crushing floating bubbles.

Therefore, if you try to configure a coating system for PCM production etc. by combining a conventional degassing treatment device and a coating device, since degassing is a batch process as described above, it will not be possible to perform continuous coating. It is necessary to defoam the paint in advance using a sufficiently large degassing device and store the defoamed paint.
As a result, degassing equipment and paint storage containers have become significantly larger.
There was a problem in that the entire coating system could not be downsized. Furthermore, when using a conventional defoaming treatment device, there is also a problem that the quality of the paint deteriorates depending on the defoaming treatment method, resulting in a decrease in the quality of the formed coating film.

Therefore, the purpose of the present invention is to solve the above-mentioned problems with conventional coating systems, and to provide a coating system that is compact, capable of high-speed continuous operation, and capable of forming a coating film of better quality. do.

SUMMARY OF THE INVENTION According to the present invention, one or more of the following objects: a new paint container;
A defoaming treatment device comprising an upper chamber and a lower chamber disposed below the upper chamber through a slit-like through-hole plate, and a means for reducing the pressure in the chamber is connected to the lower chamber; A first paint introducing means for introducing the new paint from the new paint container into the upper chamber of the defoaming treatment device: a coating device to which the defoamed paint is supplied from the lower chamber of the defoaming treatment device. ; a recovery means for recovering paint that did not contribute to the formation of a coating film in the coating device; A means for introducing the paint:
This is achieved by a painting system.

[Example] A specific example of the present invention will be described below with reference to one drawing.

FIG. 1 is a schematic diagram showing an embodiment of a coating system according to the present invention.

In Fig. 1, 2 is a paint tank that can contain new paint, 4 is a paint defoaming treatment device, and 6 is a paint! 8 is a recovery means for recovering paint that did not contribute to coating film formation in the coating apparatus.

The new paint tank 2 is provided with stirring means 2a for stirring the contained paint to make it uniform.

The paint defoaming treatment device M4 has a configuration as shown in FIGS. 2 and 3.

FIG. 2 is a longitudinal cross-sectional view of the defoaming treatment device 4, and FIG. 3 is a cross-sectional view taken along the line AA.

In FIGS. 2 and 3(a), 12 is a cylindrical container, and the inside of the container is divided into an upper chamber 14 and a lower chamber 16.

Reference numeral 18 denotes a slit-like through-hole plate that partitions the upper chamber 14 and the lower chamber 16. As shown in FIG. 1, the through-hole plate has a plurality of slots 7) 18a arranged at appropriate intervals.

The width of each slit is appropriately set according to the viscosity of the paint to be treated so that the paint passes through as an S film at an appropriate speed. For example, the slit width is between 20 and 2000 lm, preferably between 50 and 300 Bm. The interval between each slit, the thickness of the slit-like through-hole plate 18, etc. can be determined as appropriate depending on the desired setting processing conditions. Incidentally, FIG. 3(b) shows an example of the slit pattern of the slit-like through-hole plate when the container 12 is in the shape of a rectangular tube. This is a pipe for introducing the treated paint, and as shown in FIG. 1, a flow rate control pulp 20a, a pressure pump 20b, and a flow rate control pulp 20c are interposed in the middle of the pipe.

21 is a pipe for introducing the paint to be treated from the paint recovery means 8 into the upper chamber 14, and as shown in FIG. 1, a pressure pump 21a and a flow control valve 21b are installed in the middle of the pipe. Intervening.

22 is a level meter for detecting the height of the liquid level of the paint to be treated introduced into the E-side chamber 14, and the opening degree of the flow control valve 21b of the piping 21 is determined based on the detection result of the level meter 22. Set based on

Reference numeral 24 denotes a means for adjusting the airtightness of the upper and lower parts of the upper chamber 14, and the airtightness adjusting means has a corresponding opening lever pattern in the upper chamber 14, and the two parts are closely attached to each other so as to be relatively movable in the horizontal direction. It consists of two panels 24a, 24b and a driving means 24c for setting the relative positions of the panels in the horizontal direction. The two panels 24 are driven by the driving means 24c.
At least one of panels a and 24b is moved in the horizontal direction, and a ventilating space lobe pattern is formed at the position where the openings of both panels overlap, and by appropriately setting the area of the opening, the airtightness is adjusted to iA. can do. The airtight adjustment means 24 also has the function of uniformly introducing the paint to be treated onto the surface of the slit-like through-hole plate 18.

Note that the airtight adjustment means can also be omitted.

26 is a pipe for exhausting the air in the lower chamber 16 and reducing the pressure in the lower chamber, and is connected to a pressure reduction source such as the vacuum pump 2.
7, and a pressure regulating valve 26a is interposed in the middle of the pipe.

Reference numeral 28 denotes a partition wall disposed in the lower chamber opposite to the opening of the pipe 26 in the container 12, which separates the pipe opening and the paint film falling from the slit portion of the slit-like through-hole plate 18. Separated.

32 is a level meter for detecting the height of the liquid level of the paint introduced into the lower chamber 16, and the opening degree of the flow control valve 20c of the piping 20 is set based on the detection result of the level meter 32. .

A piping 34 is connected to the lower part of the lower chamber 16 and is used to transfer the defoamed paint to the coating device 6, and a pressure pump 34a and a flow control valve 34b are interposed in the piping.

The paint bag g26 and the paint collecting means 8 have a structure as shown in FIG.

Figure 4 shows painting 6 when using a curtain flow coater! FIG. 4 is a vertical cross-sectional view showing a specific configuration of a housing 6 and a paint recovery means 8. FIG.

The coating bag 226 consists of a flow coater head 6a and a belt conveyor 6b disposed below the head, and the metal plate P to be coated is conveyed on the belt conveyor in the direction of the arrow.

The paint recovery device 8 is directly below the flow coater head 6a and below the cut of the belt conveyor 6b KA'!
It consists of a gutter 8a and a receiver 8b for receiving the paint in the gutter. The pipe 21 is connected to the receiver. Although one drawing shows a case where the coating device is a curtain flow coater, the present invention can be similarly applied to a case where the coating device is a roll coater or the like.

Next, the operation of the coating system of this embodiment will be explained.

First, the valves of each pipe leading to the paint degassing treatment device 4 are
The valve 26a is closed, and the vacuum pump 27 is operated to evacuate the inside of the degassing treatment device 4, thereby reducing the pressure to a desired atmospheric pressure. The degree of pressure reduction varies depending on the viscosity of the paint, etc., but it is usually 1.
Approximately 0 to 50 Torr is appropriate.

Next, the two panels 24a and 24b of the airtight adjustment means 24
A desired airtight state is achieved by appropriately adjusting the arrangement between the spaces using the drive means 24c (note).

The airtightness adjustment means 24 is not necessarily necessary, and in that case, the airtightness operation described above is omitted).

Next, after appropriately setting the opening degrees of the valves 20a and 20c, the pressure pump 20b is operated to introduce the new paint in the paint tank 2 into the upper chamber 14 through the pipe 20. The paint to be treated introduced into the upper chamber 14 passes through the slit-like through-hole plate 18 and falls into the lower chamber 16. At this time, the inflow speed of the paint into the lower chamber 16 is determined by the atmospheric pressure in the lower chamber,
Opening area and airtightness m of the slit-like through-hole plate 18! !
! ! It is determined according to the airtightness set by means 24, paint feeding conditions, paint viscosity, etc.

Thus, the paint flowing into the lower chamber 16 from the slits 18a forms a film (curtain shape) corresponding to the arrangement pattern of the slits 18a, so that the surface area is sufficiently expanded and the paint flows into the lower chamber in a state in which N11g4 conversion is progressing. do.

For this reason, the bubbles in the paint to be treated expand under reduced pressure, and the bubble film portions on both sides of the bubbles expand and are easily and quickly crushed to release the air in the bubbles.

Note that the exhaust from the lower chamber 16 through the piping 26 is carried out through the partition wall 28.
Since this is done at a distance from the paint flow down position, the flow of paint is not disturbed and the paint does not enter the pipe.

As described above, the paint forms a thin film in the lower chamber 16, flows down while being degassed, and accumulates at the bottom of the container.

The defoamed paint thus obtained is supplied to the flow coater head 6a of the coating apparatus by operating the pressure pump 34a after appropriately setting the opening of the valve 34b.

The metal plate P is coated with the paint that flows down like a curtain from the flow coater head F6a, and the paint that does not contribute to the formation of the paint film falls into the gutter 8a and is further collected in the receiver 8b.

The paint collected in the receiver 8b is introduced into the paint chamber 14 through the piping 1 by appropriately setting the opening degree of the valve 21b and operating the pressure pump 21a, and is then introduced into the paint chamber 14 to create a new paint. It is subjected to defoaming treatment in the same manner as above.

Incidentally, when the level meter 22 detects that the paint liquid level in the upper chamber 14 has reached a predetermined height, the piping 21
The flow rate control valve 21b attached to the upper chamber 14 is automatically controlled to restrict the flow of recovered paint into the upper chamber 14.

Furthermore, when the level meter 32 detects that the paint liquid level in the lower chamber 16 has reached a predetermined height, the flow rate control valve 20c attached to the pipe 20 is automatically controlled to allow the liquid to flow into the upper chamber 14. The influx of new paints will be restricted.

Incidentally, in the above explanation, the case where the paint collected in the receiver 8b is directly introduced into the defoaming treatment device 4 has been explained, but depending on the situation, the recovered paint may be introduced into the new paint container 2. , may be further processed separately.

As described above, according to this embodiment, the necessary and sufficient amount of paint can be continuously defoamed according to the amount of paint consumed by the coating device 6, and the coating system can be operated continuously. is sufficiently usable.

Next, an example will be shown in which the characteristics of the above embodiment system were investigated.

Example 1: White polyester resin liquid paint with a viscosity of 3.2 voids (
Product name "V Knit #1500J, manufactured by Dainippon Toyo Co., Ltd.)" was used for 30 minutes. Using the system shown in Figures 1 to 4, the paint flowing down from the coating equipment was removed without the presence of the object to be coated. The entire amount was collected and subjected to defoaming treatment, and the paint was recycled in the same manner thereafter.

Here, the conditions of the defoaming treatment equipment were as follows.

Convergence of slit-like through-hole: 0.2 mm Height of slit-like through-hole: 80 mm Total opening area of slit-like through-hole: 1.28 crn' Degree of reduced pressure = 30 Torr Paint flow Et: 10.7 Jl/min Paint in coating equipment When the condition of the curtain was observed, it was found that the curtain did not break at all even after 2 hours of continuous operation and was in a stable condition.

Example 2 (comparative example): Continuous operation was carried out in the same manner as in Example 1 above, except that the degassing device was not depressurized.

When the condition of the paint curtain in the coating equipment was observed, curtain breakage occurred at a rate of once per minute for the first 10 minutes, and thereafter curtain breakage occurred frequently.

In the above embodiments, a curtain flow coater was used as an example of the coating device, but other appropriate devices may be used as the coating device in the present invention.

[Effects of the Invention] According to the present invention as described above, the paint to be treated is caused to flow down in a curtain-like manner in the degassing treatment device to increase the surface area and reduce the pressure in a thin film state, so that air bubbles in the paint are easily removed. In addition, the air can be quickly expanded and crushed to dissipate the air outside of the paint, allowing for efficient defoaming treatment.For this reason, even if the degassing treatment equipment is small, the paint to be treated can be continuously introduced into the painting equipment, allowing continuous processing. It is possible to supply a defoamed paint that satisfactorily meets the paint consumption of the market, and thus a coating system that is compact and capable of high-speed continuous operation to form a coating film of better quality can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a coating system according to the present invention. FIG. 2 is a longitudinal cross-sectional view showing the defoaming treatment device, and FIG. 3 is a cross-sectional view taken along the line AA. FIG. 4 is a longitudinal sectional view showing the specific structure of the coating device and paint recovery means during coating. 2: New paint tank, 4: Defoaming treatment equipment. 6: Painting device, 8: Paint collection means, 12: Container,
14: Upper chamber. 16: Lower chamber, 18 Nislit-like through-hole plate, 18a Nislit, 20.21, 26.34 = Piping, 22, 32 Nirepel meter. 24: Airtight 7A adjustment means, 28: Partition wall. 2nd S1

Claims (5)

[Claims] (1) Container for new paint; has an upper chamber and a lower chamber disposed below the upper chamber through a slit-like through-hole plate, and a means for reducing the pressure in the chamber is connected to the lower chamber. a defoaming treatment device; a first paint introducing means for introducing the new paint from the new paint container into the upper chamber of the degassing treatment device; defoaming treatment from the lower chamber of the defoaming treatment device; A coating device to which the finished paint is supplied; a recovery means for recovering paint that did not contribute to the formation of a coating film in the coating device; and, if necessary, the recovered paint is transferred from the recovery device to a chamber above the defoaming treatment device. a second paint introducing means for introducing the paint into the paint system. (2) The first paint introduction means is attached with a first paint introduction amount adjusting means, and the defoaming treatment device is attached with means for detecting the height of the paint liquid level in the lower chamber, and the detection 2. The coating system according to claim 1, wherein said first paint introduction amount adjusting means is operated in accordance with the paint liquid level detected by said means. (3) The second paint introduction means is attached with a second paint introduction amount adjusting means, and the defoaming treatment device is attached with means for detecting the height of the paint liquid level in the upper chamber, and the detection 2. The coating system according to claim 1, wherein said second paint introduction amount adjusting means is operated in accordance with the paint liquid level detected by said means. (4) The coating system according to claim 1, wherein the coating device is a curtain flow coater. (5) The coating system according to claim 1, wherein the coating device is a roll coater.