JPH0578395B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an apparatus for applying a desired coating material to the surface of a base material such as a plate or a rod and adjusting the thickness of the coating film.

<Prior art and its problems> For painting base materials such as board materials (e.g. decorative boards, shelf boards, etc.), bar materials (e.g. baseboards, surrounding edges, etc.), processed materials (e.g. window frames, doors, etc.) Various methods and devices have been used in the past.

One such device is a so-called dipping coating device. This has the advantage that even if the surface of the base material is uneven, coating can be easily performed with a simple operation.

However, dip coating is mainly applied to sheet-like objects, and it has been impossible to continuously apply dip coating to the above-mentioned substrates. Furthermore, when using dipping coating, not only does the amount of coating generally tend to be excessive, but it is also difficult to adjust the amount of coating. This is because, although the amount of coating is highly correlated with the viscosity of the paint, it is extremely difficult to maintain the viscosity of the paint strictly constant. The viscosity of the paint also affects the penetration of the paint components into the base material, and in order to achieve a uniform coating, it is necessary to increase the viscosity of the paint to a certain extent and apply thickly, so adjusting the amount of application is difficult. It becomes even more difficult. Furthermore, it is necessary to support the substrate for a while after removing it from the paint tank in order to allow excess paint adhering to it to flow down, but this process takes extra time and also reduces the amount of paint. Uneven application occurs due to sharpness and sag.

Spray painting equipment is also known. However, this results in a large amount of paint loss, and the nozzle is easily clogged due to dust and paint scum in the paint. Therefore, paint management and nozzle maintenance and inspection must be carried out frequently, which reduces work efficiency. However, it has the disadvantage of increasing costs.

The present applicant has repeatedly conducted experiments and considerations from the viewpoint of solving the drawbacks of the conventional coating equipment described above, and has developed a coating box that has a supply port for supplying the base material to be coated with paint and an outlet for taking out the coated product. Then, while supplying paint into the paint box beyond the level of the supply port and take-out port, the pressure inside the paint box is reduced and the paint overflows from the supply port and take-out port due to the vacuum suction force. The paint is applied to the entire surface or a desired surface portion of the substrate while the substrate is moving from the supply port to the take-out port, and the base material is removed by a high-speed air flow at the take-out port caused by suction. The company has already filed several patent applications for coating equipment and coating methods whose main feature is to remove excess paint adhering to materials.

The coating technology proposed by the applicant maintains the inside of the coating box in a reduced pressure state, and uses this reduced pressure suction force to prevent paint from overflowing from the supply and removal ports, so that it is continuously applied to the substrate. In addition to making it possible to apply coating by dip coating, the excess amount of paint applied to the substrate is wiped away by the high-speed air flow that flows into the paint box from the outlet due to this reduced pressure suction force. However, it is possible to form a coating film with a desired thickness. An auxiliary opening adjustment plate member is attached to the openings of the supply port and the extraction port so that the size and shape of the substrate can be adjusted. By adjusting the gap formed, the flow velocity of the air flow flowing in from the outlet is adjusted, and the coating film thickness can be arbitrarily adjusted.

By the way, flow coaters and roll coaters are known as other conventionally known coating devices.
These methods do not require a large amount of paint to be constantly filled in the paint box as is the case with the dipping method, so there is less risk of quality deterioration or contamination of the paint over time. However, when painting with only a flow coater, it is possible to form a thick coating film by increasing the amount applied to the base material, but when the base material has minute irregularities such as pinholes, the paint bridging phenomenon may occur. Therefore, the paint does not fully enter into the minute recesses, causing color unevenness. On the other hand, roll coaters apply paint by press-fitting the paint onto the surface of the base material, so even if there are minute irregularities on the base material, the paint can penetrate into the recesses. It is difficult to increase the amount of coating applied to the material, and it is not possible to form a thick coating film. In view of these circumstances, coating equipment that combines these flow coaters and roll coaters has been proposed, but since the roll coater performs press-fitting, it is still difficult to increase the coating amount. Ta.

<Means for solving the problems> The present invention has been devised by further devising in consideration of the above-mentioned circumstances, and has been devised by taking full advantage of the advantages of the coating technology proposed by the applicant. It is an object of the present invention to provide a new coating device that can simultaneously achieve the advantages of conventional roll coaters and flow coaters.

That is, the present invention that can achieve such objects is as follows:
a coating box having at least one pair of a supply port for supplying a base material to be coated and a take-out port for taking out a coated product; a paint tank provided at a lower part of the paint box; a coater head provided at the top of the coating box for flowing the coating material down onto the substrate being transported; a coating supply means for supplying the coating material from the coating tank to the coater head; a depressurizing means for reducing the pressure inside the box to cause an air flow to flow into the painting box from the outlet and removing an excess amount of the paint adhering to the base material by the air flow; By changing the opening area of at least one of the supply port and the take-out port,
The coating adjustment device is characterized in that it has an opening adjustment means for adjusting the amount of paint applied by adjusting the area between the openings and changing the flow rate of the air flow.

<Function> While the substrate is being transported from the supply port to the take-out port of the coating box, the paint flowing down from the coater head provided at the top of the coating box adheres to the surface of the substrate and is coated. A portion of the paint flowing down from the coater head falls to the bottom of the coating box without adhering to the surface of the substrate and stays there, and is supplied to the coater head by a pump or the like and used for circulation. however,
Since the pressure inside the coating box is reduced, a portion of the paint falling from the coater head is caught in the turbulent airflow generated within the coating box due to the reduced pressure and gradually falls while floating. Therefore, the surface of the base material is not only directly coated with the paint flowing down from the flow coater, but also indirectly coated with the paint floating inside the paint box. Paint is continuously deposited while being conveyed from the supply port to the take-out port.

Due to the reduced pressure inside the paint box, air flows in at high speed from the supply and outlet ports, thereby preventing floating paint from flowing out of the paint box.

Moreover, the air flow flowing into the coating box from the outlet removes excess paint adhered to the surface of the substrate, and adjusts the coating thickness to a predetermined thickness.

The amount of paint applied to the surface of the substrate depends on factors such as the viscosity of the paint, the reduced pressure inside the coating box (negative pressure), and the conveyance speed of the substrate. The amount of application can be adjusted by appropriately combining and adjusting the amounts. In addition to the pressure reduction means, a secondary air intake is attached to the painting box.
By adjusting the amount of air taken in from this secondary air intake port, it is possible to finely adjust the negative pressure inside the coating box, thereby achieving fine and precise adjustment of the amount of coating. .

In addition, the relationship between the dimensions and shape of the outlet and the cross-sectional dimensions of the substrate, that is, the area between the two and Since this is a factor that determines the flow rate of the high-speed air flow, the amount of coating can be adjusted by adjusting the area between the ends. This adjustment of the opening according to the cross-sectional size and shape of the base material is possible by providing an opening adjustment plate at the supply port and the take-out port. Furthermore, by appropriately adjusting the positional relationship between the openings of the supply and outlet ports and the substrate, coating films of different thicknesses can be formed on each side of the substrate.

In order to prevent the substrate from vibrating vertically and horizontally during transportation within the coating box due to the turbulence generated within the coating box due to the reduced pressure, provide appropriate guide support means between the supply port and the outlet. be able to. Furthermore, if a coating surface is formed on this guide support means to cover a part of the surface of the substrate over the entire length in the substrate conveyance direction, paint adhesion to the portion covered by the coating surface is prevented, and the substrate The paint can be applied only to a desired surface portion or a desired surface.

The movable shield plate may be installed at either or both of the supply port and the take-out port of the paint box. The movable shielding plate is opened and closed in synchronization with the conveyance of the substrate, and maintains the substantial opening area of these openings approximately constant whether or not the substrate is present in these openings,
The scraping of excess paint achieved by the airflow flowing into the paint box from the outlet can be accomplished with a relatively small vacuum suction force. From this point of view, when the movable shielding plate is installed in only one of these openings, it is desirable to install it at the outlet.

The coating roll that can be installed in the coating box is in pressure contact with the surface of the base material, and even when the surface of the base material has minute irregularities,
The paint is press-fitted into the minute recesses to achieve an even coating. The applicator roll is made of any elastic material necessary to achieve this effect, such as rubber or sponge. One or more coating rolls are installed as necessary so as to be in pressure contact with a desired surface onto which the paint is to be press-fitted, such as the front side, back side, or side side of the base material.

Since the paint gets caught up in the turbulence and stays in the paint box, the paint still adheres to the base material even after the paint is press-fitted by the paint roll. Therefore,
Regardless of the presence or absence of a coating roll, the amount of paint deposited on the substrate depends solely on the air flow rate determined by the vacuum suction force of the pressure reducing means and the opening area of the outlet (the area between the opening and the substrate). to be controlled.

<Example> FIGS. 1 and 2 schematically show an example of a coating apparatus according to the present invention. The coating box 10 has a supply port 11 for supplying the base material to be coated (FIG. 2) and an outlet 1 for taking out the coated base material.
A pair with 2 is formed. These supply ports 11
In order to make this device applicable to substrates having various cross-sectional dimensions and shapes, the opening area of the outlet 12 is determined in advance to correspond to the maximum dimension and shape of the substrate assumed, and as necessary. An adjustable or replaceable aperture regulating plate is provided to limit the size and shape of the apertures accordingly. In the illustrated embodiment, an opening adjustment plate 11' is provided at the supply port 11.
In addition, an opening adjustment plate 12' is provided at each outlet 12, and functions to limit the area of these openings depending on the cross-sectional size and shape of the substrate to be coated. In order to limit the opening area, a plurality of aperture plates having different aperture dimensions and shapes may be prepared and used interchangeably, or an adjustment plate for adjusting the vertical dimension and shape and a horizontal dimension may be used. An adjustment plate for adjusting the shape may be provided, and the overall size and shape may be adjusted by combining and adjusting the position of a plurality of adjustment plates.

The base material is conveyed in the direction of the arrow by a conveyor such as a roller or conveyor 19a, introduced into the coating box 10 from the supply port 11, guided on the guide bar member 13 inside the coating box, passed through the take-out port 12, and is coated. The product is taken out of the box and further transported in the direction of the arrow by a transport means such as rollers or a conveyor 19b. In the illustrated embodiment, the guide bar member 13 is simply shown as a roll bar that supports the lower surface of the base material, but as will be described later, the pressure inside the painting box 10 is reduced by a pressure reducing means, and the pressure generated by this is reduced. Since turbulence may vibrate the substrate being conveyed through the coating box 10, the guide bar member 13 may
Alternatively, a damping member for preventing vibration in the vertical direction can be optionally installed.

A lid 14 is provided to close the open top surface of the coating box 10 for cleaning, maintenance, inspection, etc. inside the coating box 10. Since the pressure inside the painting box 10 is reduced as will be described later, the lid 14 has a structure that allows the painting box to be hermetically sealed.

The lower part of the paint box 10 serves as a paint tank 15. The paint in the paint tank 15 is supplied via a pipe 16 and a pump 17 to a coater head 18 provided along almost the entire width at the top of the paint box 10. These paint tank 15, piping 16, and pump 17 constitute paint supply means for the coater head 18.

The coater head 18 has a slit 18a formed along its entire width at the bottom so that the coating material flows down onto the substrate conveyed from the supply port 11 toward the take-out port 12. Thus, according to the conventional flow coater method, coating is performed on the substrate in the same manner.

The pressure reducing means 30 includes a vacuum pump 31 and piping 32, and reduces the pressure inside the coating box 10.

The baffle plates 20, 20, which project diagonally toward the paint tank 15 inside the paint box 10, allow the paint that is about to be sucked in along with the air due to the reduced pressure inside the paint box to adhere there, as shown by the arrows in the figure. By allowing the paint to drip naturally and collecting it in the paint tank 15, it constitutes a gas-liquid separation means that functions so that only air is sucked through the piping 32. At this time, in order to return the paint adhering to the baffle plate 20 to the paint tank 21 without drying it, it is desirable to coat the surface of the baffle plate 20 with a resin, or to pour or spray a solvent on the surface of the baffle plate 20.

The vacuum pump 31 reduces the pressure inside the coating box 10 to a predetermined level. With this pressure reduction, supply port 1
Atmospheric air is sucked in at high speed through the openings of 1 and the outlet 12 to prevent the paint from flowing out from the coating box 10, and to retain the paint in the resulting turbulence, thereby preventing the paint from flowing into the coating box 10. Provides continuous paint adhesion. The paint floating in the turbulence gradually falls and is collected in the paint tank 15 for circulation. The partition wall 21 provided in the paint box 10 to isolate the paint box 10 facilitates the recovery of floating paint, and forms an air communication path 22 here by narrowing the distance from the inner wall of the paint box. This serves to enhance the depressurizing effect at the top of the painting box.

When the substrate 1 approaches the outlet 13, it is coated directly with the paint flowing down from the coater head 18 and then indirectly coated with the paint floating in the coating box. From there, it encounters a high-speed suction air stream that blows away the paint that has adhered to the surface of the base material in excess, drying it to the point where it is dry to the touch.

FIG. 3 schematically shows a coating device according to another embodiment of the invention. The same parts and elements as those of the apparatus shown in FIGS. 1 and 2 are given the same reference numerals, and detailed explanation thereof will be omitted.

In the apparatus according to the embodiment shown in FIG.
3 is provided. This movable shielding plate 23 is constructed of a single plate member or an assembly of a plurality of divided plate pieces, and is moved vertically or horizontally by a known drive mechanism (not shown) such as a cylinder or gear. The opening area of the outlet 12 can be adjusted as desired.

In the apparatus of this example in which a movable shielding plate 23 is installed at the outlet 12, when there is no base material in the coating box 10, the movable shielding plate 23 is placed in a position that narrows the opening area of the outlet 12 (hereinafter referred to as a closed position). When the base material passes through the outlet, it forms an opening area that can be slightly larger than the cross-sectional dimensions and shape of the base material (hereinafter referred to as the "opening position").
The movable shield plate is actuated and held in this open position during passage of the substrate. In this case, a formation is formed between the narrowed opening area of the outlet 12 when the movable shielding plate is in the closed position and the cross section of the base material passing through the outlet when the movable shielding plate is in the open position. Consideration will be given so that the area between the two areas is approximately the same.

In this way, by providing the movable shielding plate 23 at the outlet 12 and operating in synchronization with the conveyance of the substrate,
Whether the base material passes through the outlet or not, the actual opening area can be kept almost constant at all times.
The flow rate of the air flow sucked from the base material 2 is always kept constant, and the coating film on the base material can be precisely adjusted. Furthermore, since the narrowed opening area is maintained in this manner, the vacuum suction force in the pressure reducing means 30 may be relatively small.

It is preferable that the movable shielding plate 23 is configured to be automatically operated in synchronization with the conveyance of the base material, and for this purpose, a detection device for detecting the presence or absence of the base material is provided behind the supply port 11 in the direction of conveyance of the base material. 24 will be installed. Any type of detection device known in the art can be used, and includes a detection sensor such as a phototube, a limit switch, a proximity switch, a linear transformer, or the like. When the detection device 24 detects the arrival of the tip of the substrate immediately below the movable shielding plate 23 in the above-mentioned closed position with no substrate present in the apparatus, the detection device 24 and the extraction port 12 and the substrate conveyance speed, the movable shielding plate 23 is automatically activated to move the opening position This allows the base material to be carried out from the outlet. Thereafter, when the rear end of the base material is detected by the detection device 24, the movable shielding plate 23 is moved after a certain period of time (that is, immediately after the rear end of the base material passes the outlet 12).
It automatically operates and moves to the closed position, and the outlet 12
The opening area is narrowed. In this way, the opening area of the outlet 12 is always automatically adjusted to be substantially constant. In order to operate the movable shielding plate 23 after a certain period of time has passed after detection by the detection device 24,
A known timer, pulse generator, etc. may be used as appropriate.

In the embodiment shown in FIG. 3, an aperture adjusting plate 12' and a movable shielding plate 23 are provided with respect to the outlet 12. Before using this device, the aperture adjusting plate 12' is operated as appropriate depending on the cross-sectional size and shape of the base material to be coated, and is fixed at a position where a desired opening area is formed, and the aperture adjusting plate 12' is fixed at a position where a desired opening area is formed, and the aperture adjusting plate 12' is operated as appropriate depending on the cross-sectional size and shape of the base material to be coated, and is fixed at a position where a desired opening area is formed. It will remain in that position as long as it continues. As a result, the distance between the opening area and the base material when the base material passes through the outlet is adjusted to a predetermined area, and an air flow velocity that provides the desired coating film thickness can be obtained. During operation of this device, the movable shielding plate 23 is reciprocated between an open position and a closed position depending on the presence or absence of a base material at the outlet, and changes the area of the opening when no base material is present at the outlet. The area is controlled to be approximately equal to the predetermined interspace area.

The apparatus according to the embodiment shown in FIG. 3 is further provided with an applicator roll 25 in the coating box 10 adapted to press against the surface of the substrate. In some cases, a plurality of application rolls may be provided along the substrate conveyance direction, and may be configured to come into pressure contact with a desired surface of the substrate. The coating roll 25 is attached to the coating box 10 so as to be in pressure contact with the entire width of the surface of the base material.
It will be suspended horizontally between the walls on both sides.

Although not shown, it is preferable to provide an elevating means that allows the application roll 25 to move in the vertical direction. In this embodiment, the supply port 11
and the opening area of the outlet 12 is the opening adjustment plate 11',
12' is required in order to be able to press the applicator roll against substrates of different thicknesses. In addition, when coating a base material with a smooth surface without minute irregularities or a base material with a relatively large irregular surface, the coating roll 25
Since there is no need to try to press-fit the coating material by using the coating roll 25, it is advantageous to provide a means for raising and lowering the coating roll 25 for this purpose as well.

As described with respect to the embodiment shown in FIGS. 1 and 2, a turbulent air flow is generated in the coating box 10 as a result of the reduced pressure, and a portion of the paint flowing down from the coater head 18 is trapped in this turbulent air flow. paint box 10
Floating throughout the interior. Therefore, the coating roll 25
Although the coating film thickness on the base material is once reduced to a considerable extent due to the pressure applied thereto, floating paint adheres to the base material until it reaches the outlet 12, increasing the coating film thickness. Final thickness adjustment is then performed by the suction air flow at the outlet 12.

<Effects of the invention> In the same manner as the conventional flow coater method, paint can be applied by flowing the paint onto the base material, and high-speed air flow from the base material outlet obtained by vacuum suction inside the paint box When the paint is taken out from the outlet, the paint excessively adhered to the surface of the base material is blown away, and by utilizing this phenomenon, the thickness of the paint film can be easily adjusted.

If a coating roll is provided in the coating box and is configured to be brought into pressure contact with the surface of the substrate coated with the flow coater, effective coating can be achieved even on porous substrates having minute irregularities. Moreover, in this case as well, the coating film thickness is adjusted by the air flow rate sucked from the outlet, and a relatively large amount of coating material can be deposited, which was not possible with the conventional roll coater method.

[Brief explanation of the drawing]

FIG. 1 is a plan view schematically showing one embodiment of a coating device according to the present invention, FIG. 2 is a sectional view taken along the line of FIG. 1, and FIG. FIG. 2 is a plan view schematically shown in the same manner as FIG. 1; Explanation of symbols, 10... Paint box, 11... Supply port, 12... Outlet, 11', 12'... Opening adjustment plate, 15... Paint tank, 18... Coater head, 23... Movable shield Board, 24...Detection device, 2
5... Application roll, 30... Pressure reduction means, 31...
Vacuum pump.

Claims (1)

[Claims] 1. A coating box having at least one pair of a supply port for supplying the base material to be painted and a take-out port for taking out the coated product, a paint tank provided at the bottom of the paint box, and a supply port from the supply port to the take-out port. a coater head provided at the top of the paint box for flowing the paint onto the substrate being conveyed; a paint supply means for supplying the paint from the paint tank to the coater head; a depressurizing means for reducing the pressure inside the painting box and causing an air flow to flow into the painting box from the outlet, and removing an excess amount of the paint adhering to the substrate by the air flow;
By changing the opening area of at least one of the supply port and the take-out port of the paint box to adjust the area between the paint box and the base material, and by changing the flow rate of the air flow, the paint adheres. A coating adjustment device characterized by having an opening adjustment means for adjusting the amount.