JP3730529B2 - Method and apparatus for coating porous material - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for applying a paint to the surface of a porous material having irregularities and bubbles on its surface (for example, lightweight cellular concrete, hereinafter also referred to simply as an ALC plate or an ALC outer wall material). And its device In particular, a coating method for preventing air from being trapped in the bubbles existing on the surface of the ALC plate (generation of air reservoir) and forming a coating film by causing the paint to flow into the entire inner peripheral surface of the bubbles as well as It relates to a painting device.
[0002]
[Prior art]
Conventionally, as the outer wall of a building, there were many outer walls to be constructed at the construction site, such as a soil wall coated with soil, but recently, the outer wall material was produced at a factory etc., and this outer wall material was used as the outer wall of the building. The outer wall attached to the part has become widespread because it can be constructed quickly, homogeneously and with good appearance. As the outer wall material produced in the factory, there are many ALC (Autoclaved Light-weight Concrete) outer wall materials, precast concrete outer wall materials, hard wood cement board outer wall materials, and the like.
[0003]
In particular, many ALC outer wall materials are produced because they are similar in appearance to precast concrete outer wall materials and are light and easy to construct. And, as an outer wall material of a building such as a house, a recently provided concavo-convex pattern is favored by the construction owner because of its gorgeous appearance.
[0004]
In such an outer wall material, a coating is usually applied to the surface in order to improve the appearance and prevent moisture from being absorbed. Conventionally, there are a brush coating method, a spray coating method, a roll coater, a flow coater, a dipping method and the like as a coating method for applying a paint to the surface of such an outer wall material.
[0005]
The brush coating method is a method in which the surface of the outer wall material is stroked and applied with a brush to which a paint is applied, and is the most primitive method. This brush application method is suitable for repairing the coating surface of small-scale production outer wall materials and outer wall materials because the brush is put in the paint reservoir, the paint is attached to the brush, and this brush is applied by stroking the outer wall material surface. However, since it is not suitable for mass production, it is not adopted in the mass production process of outer wall materials.
[0006]
On the other hand, the spray coating method is a method of spraying paint from a nozzle at the tip of the spray and spraying the sprayed paint on the surface of the outer wall material, and there are an air spray method and an airless spray method. The air spray system is composed of a compressed air passage that leads to the nozzle at the tip of the spray gun and a passage that leads from the paint reservoir to this compressed air passage. When compressed air is passed through the nozzle at the tip, the compressed air passage is depressurized, the paint in the paint reservoir is sucked through the passage that leads to the compressed air passage, and the sucked paint and air are combined. It is a method of painting out the nozzle.
[0007]
The airless spray system has a passage from the paint reservoir to the nozzle at the tip of the spray gun. When compressed air is introduced into the paint reservoir, the pressure of the compressed air causes the paint in the paint reservoir to enter the passage. In this method, the paint is extruded and sprayed from the nozzle at the tip of the spray gun. Since this spray coating method can spray paint on the surface of the outer wall material, it can be applied to a deeply carved outer wall material, and is used for coating various outer wall materials.
[0008]
In addition, after airless spray painting, combination painting such as a method of scraping off excess paint with an air knife etc. that produces an air jet in a slit shape, a method of applying an air jet in a pressure booth after passing through a decompression booth after spray coating, etc. It has been adopted.
[0009]
[Problems to be solved by the invention]
However, even with the conventional spray coating method, which is considered to be the most effective method for coating the surface of the outer wall material, many problems have arisen when coating the outer wall material made of ALC that is deeply carved. It was. That is, when there is a deep carving such as a groove, there is a problem that the amount of paint applied by spraying differs between the groove and the non-groove.
[0010]
In addition, when the outer wall material made of ALC is manufactured, many bubbles appear on the surface and become fine holes (irregularities). After the formation of the coating film, the air reservoir breaks and the portion is not painted or the coating film is thin. In addition, the paint scraping with an air knife after spray coating and the method of reducing the paint thickness to a uniform thin film by using a decompression booth + pressurization booth reduces the amount of paint remaining in the grooves, but prevents the coating from being formed inside the bubbles. is there.
[0011]
For example, as shown in FIG. 8 (a), a part of an ALC plate having a coating film formed on a conventional surface is schematically illustrated, and the coating is applied to the surface of the ALC plate 1 using a waterproof coating device. When 2 was formed, the air reservoir 5 was formed in a state where air was sealed by the coating film 2 inside the numerous bubbles 3 present on the surface of the ALC plate 1.
[0012]
However, if the hole diameter of the bubble 3 is large, as shown in FIG. 8 (b), when time passes and the atmospheric pressure changes, the air reservoir 5 in the bubble 3 expands and repels. There was a problem that pinholes 4 were formed in the film 2.
[0013]
FIG. 9A is a micrograph of the surface of the ALC plate 1 and shows a state where pinholes 4 are formed in the coating film 2 as shown in FIG. 8B. FIG. 9B is a photomicrograph of the longitudinal section of the ALC plate 1, and shows a state in which the coating film 2 is not formed without the paint being pushed into the bubbles 3 existing on the surface side of the ALC plate 1. Show.
[0014]
One way to solve this problem is to apply a thick coating, but this requires a large amount of paint (coating composition), which is still insufficient as a solution. There were some problems. FIG. 10 schematically shows a state in which a very thick coating film 2 is formed on the surface of the ALC plate 1.
[0015]
Coating method according to the present invention And its device Is a completely new invention developed in view of the above-mentioned many problems. In particular, the porous material is pressurized and sprayed onto the surface of the porous material, and the paint is pushed into the bubbles provided on the surface. The invention provides a completely new coating method and coating device apparatus in which a coating film is formed by expanding and rupturing an air reservoir confined in bubbles by reducing the pressure of the surface of a coating liquid film of a material.
[0016]
[Means for Solving the Problems]
The coating method according to the present invention is an invention that has fundamentally improved the above-mentioned many problems, and the gist of the invention of the coating method is that a waterproof coating film is formed on the surface of a porous material in which a large number of bubbles are present. In the coating method of forming a coating film on the surface of the porous material, the coating material is pressed into the bubbles of the porous material to form a coating liquid film having a predetermined thickness, The excess paint on the surface of the porous material is removed by removing means, The paint liquid film surface of the porous material is depressurized to expand and rupture air pockets in the bubbles confined by the formation of the paint liquid film to form a coating film on the paint liquid film surface. A coating method for a porous material, characterized in that a coating liquid is formed by injecting a coating liquid into the entire surface of the bubbles by blowing air. It is.
[0017]
Book In the coating method of the invention, since the paint is sprayed onto the surface of the porous material, the entire surface of the porous material is coated by pushing the paint into the bubbles existing on the surface of the porous material. A coating liquid film having a predetermined thickness can be formed.
[0018]
Also book In the coating method of the invention, after the coating material is pressurized and sprayed onto the surface of the porous material, the coating material is applied to the surface, and then the excess coating material adhering to the surface is applied. Blowing air Since it is removed, the thickness of the paint formed on the surface of the porous material can be kept constant, and the removed paint can be reused, which is extremely economical.
[0019]
Also Book In the coating method of the invention, since the coating liquid film surface of the porous material is decompressed after the coating liquid film having a predetermined thickness is formed on the surface of the porous material, the coating liquid film is confined by the formation of the coating liquid film. The air reservoir in the bubbles can be expanded and ruptured, and the air in the bubbles that causes a large generation of pinholes can be discharged and removed in advance.
[0020]
Also book In the coating method of the invention, the air reservoir in the bubbles confined by the formation of the coating liquid film is expanded and ruptured by decompression of the coating liquid film surface of the porous material, and then the air is applied to the surface of the coating liquid film. As a result, the paint liquid film that forms a paint liquid film and still has fluidity is allowed to flow into the entire surface of the bubbles to form a coating film, thereby preventing an unpainted portion from being provided in the bubbles.
[0021]
The gist of the invention of the coating apparatus according to the present invention is that the coating apparatus forms a waterproof coating on the surface of the porous material in which a large number of bubbles are present, and the paint is sprayed on the surface of the porous material. A pressure spraying device that pushes the paint into the large number of bubbles, a removal device that removes excess paint, and a pressure reduction of the coating liquid film surface of the porous material to reduce the coating liquid film into the large number of bubbles. It is characterized by comprising a combination of a decompression device for expanding and rupturing an air reservoir confined by formation and an air spraying device for injecting coating liquid into the bubbles by spraying air onto the surface of the coating liquid film. This is a porous material coating device.
[0022]
In the above-described invention of the coating apparatus, a pressure spraying apparatus capable of strongly spraying the paint onto the surface of the porous material is provided, so that the paint can be pushed into the bubbles existing on the surface of the porous material by this apparatus. I can do it. In addition, the excess paint applied to the surface of the porous material can be removed by the removing device.
[0023]
In addition, since the coating device is provided with a pressure reducing device, the pressure of the coating material liquid film surface of the porous material is reduced by this device, so that the air confined by the formation of the coating liquid film in many bubbles is formed. The reservoir can be removed from the bubbles by expanding and bursting.
[0024]
further, In the coating apparatus of the present invention, Since an air spraying device is provided, air is strongly blown onto the coating liquid film applied to the surface of the porous material with this device, so that a large number of bubbles existing in the surface of the porous material can be applied to the coating material. It can be made to flow in and a coating film can be formed in a bubble.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Drawing method according to the present invention And its FIG. 1 is a simplified illustration of an apparatus for carrying out the coating method of the present invention, FIG. 2 is a sectional view of a filter attached to the apparatus of FIG. 1, and FIG. FIGS. 4A, 4B, 4C, and 4D are cross-sectional explanatory views showing steps of forming a coating film in bubbles on the surface of the ALC plate, respectively. .
[0026]
FIG. 5 is a cross-sectional enlarged explanatory view of the main part of the ALC plate of the present invention, and FIG. Manufactured by method FIG. 6 (b) is a micrograph of a longitudinal section of the main part of FIG. 6, and FIGS. 7 (a) and 7 (b) are vertical sections of the main part of FIG. 6 (a). FIG.
[0027]
The method and apparatus according to the present invention will be described with reference to FIG. In the figure, reference numeral 10 denotes the entire coating apparatus according to the present invention. A preheating portion 25 that preheats the ALC plate 11 and a coating that applies a paint to the surface of the ALC plate 11 with respect to the ALC plate 11 that is the target of the apparatus. Part 30.
[0028]
The aforementioned ALC plate 11 is preheated to, for example, 40 to 50 ° C. in the preheating unit 25. Next, the ALC plate 11 placed on the transport rollers 72 and 73 is sent in the direction of the arrow a in the figure by the rotation of the transport rollers 72 and 73, whereby each process by the coating unit 30 is sequentially performed on the ALC plate 11. It is made to be done.
[0029]
The coating apparatus 10 is provided with a control unit 22, and the control unit 22 controls each part of the coating apparatus 10 according to the input command.
[0030]
As described above, the ALC plate 11 heated to a predetermined temperature in the preheating unit 25 is sent to the coating unit 30. A sensor 26 for detecting the presence or absence of the ALC plate 11 is provided in the vicinity of the carry-in entrance of the ALC plate 11 of the coating unit 30. The sensor 26 may be a sensor that irradiates a carry-in path of the ALC plate 11 and detects the presence or absence of the ALC plate 11 based on the intensity of the reflected light.
[0031]
The control unit 22 constantly monitors the detection result of the sensor 26. When the control unit 22 detects that the ALC plate 11 has been carried in, the control unit 22 operates each part of the coating unit 30 to perform the coating process on the carried ALC plate 11. The painting unit 30 is made to execute.
[0032]
The coating unit 30 has a casing 31 that shields an internal coating processing space from an external space. This coating processing space is divided into four processing spaces by partition walls 42, 43 and 44. Among these four processing spaces, the first processing space provided on the carry-in side of the ALC plate 11 is a pressurizing spray chamber for pressurizing and spraying the paint, and is applied to the surface of the ALC plate 11. There is a spray coating unit 32 for hitting the paint (coating composition) 12 at a high pressure, and the paint 12 is supplied from the pump 52 to the spray nozzle 54 via the pipe 51.
[0033]
At this time, the coating 12 has a coating striking force of 2 g / cm on the surface of the ALC plate 11 while the pressure is controlled by the hydraulic pressure gauge 53. ² Or more (preferably 10 g / cm ² This is sprayed onto the surface of the ALC plate 11 with such pressure. As a result, the paint is almost pushed into the fine holes on the surface of the ALC plate 11. Incidentally, a shutter 41 for preventing the paint 12 from leaking outside from the carry-in port of the ALC plate 11 is provided in the first processing space constituting the spray coating section 32.
[0034]
The ALC plate 11 on which the lump of the paint 12 is sprayed on the surface of the spray coating unit 32 by high-pressure spray is fed into the second processing space by the rotation of the transport rollers 72 and 73. This second processing space is an air blowing chamber that removes excess paint by air blowing. By blowing air to the paint 12 in a state of being piled up on the surface of the ALC plate 11, An air blow part 33 for scraping off excess paint from the surface is provided. Air is supplied to the air cutter 65 provided in the air blow part 33 from the blower part 61 via the air distribution chamber 62, and the supplied air is a pair of air cutters 65. Are supplied to the air blow plates 65A and 65B, and high-pressure air is blown against the coating material of the ALC plate 11 from their tip portions.
[0035]
In this way, the ALC plate is sent in the direction of arrow a by the rotation of the transport rollers 72 and 73 while air is blown by the air cutter 65, so that excess paint is removed from the paint on the surface. Is done. The removed paint flows down from both sides of the ALC plate 11 to the collection tank 46. The paint 12 collected in the collection tank 46 is sent to the pipe 75 by the pump 74 and supplied to the filter provided at the end of the pipe 75.
[0036]
FIG. 2 is a cross-sectional view showing the filter 90 provided at the end of the pipe 75 (FIG. 1). As shown in FIG. 2, the filter 90 is for removing impurities (ALC powder and the like) from the paint 12 discharged from the collection tank 46 (FIG. 1). A wire mesh 92 is provided for passing and filtering. The recovered paint that has passed through the wire mesh 92 is removed from the impurities and stored in the tank 96. The filtered paint collected in the tank 96 is returned again to the coating apparatus 10 (FIG. 1) by the pump 97 and spray-painted on the ALC plate 11 in the spray-coating part 32 in the same manner as described above with reference to FIG. The
[0037]
Further, impurities such as ALC powder removed from the recovered paint in the filter 90 (FIG. 2) are stored in the waste tank 95. As described above, in the coating apparatus 10, excess paint that has been scraped off by the air cutter 65 is collected in the collection tank 46 and then reused through the filter 90, thereby increasing the use efficiency of the paint. It is made to become.
[0038]
The ALC plate 11 from which excess paint has been removed in the air blow section 33 of the coating apparatus 10 shown in FIG. 1 is fed into the third processing space by the rotation of the transport rollers 72 and 73. This third processing space is a processing space for depressurizing the surface of the coating liquid film applied to the surface of the ALC plate 11, and is a bubble in which the coating material 12 has not completely entered the surface of the ALC plate 11, that is, the coating material. This is a decompression chamber 34 for expanding and rupturing an air reservoir in the state of air confined in the remaining bubbles by forming a liquid film. By drawing out air by the blower unit 61, the pressure inside the decompression chamber 34 is maintained at a pressure lower than the atmospheric pressure by 1.5 KPa or more, so that the air in the air reservoir in the bubbles expands. At this time, if there is little removal of the excess paint in the air blow section, the coating liquid film on the bubble inlet becomes thick and cannot be repelled due to the expansion of the air in the bubbles, resulting in unpainted areas.
[0039]
In the decompression chamber 34, the ALC plate 11 in which the air reservoir in the air bubbles in the coating portion has burst is sent to the fourth processing space that continues as the transport rollers 72 and 73 rotate. This fourth processing space is a pressurizing chamber that blows air onto the coating liquid film applied to the surface of the ALC 11, and the paint is pressurized inside the bubbles where the air reservoirs in the bubbles are opened. A pressurizing chamber 35 is provided for flowing in by the flow of air. Pressurized air is supplied to the pressurizing chamber 35 from the blower portion 61 through the air distribution chamber 62. An air flow as indicated by an arrow b in the figure is generated in the decompression chamber 34 adjacent to the pressurization chamber 35, and the surface of the ALC plate 11 is sent through the air flow. The paint part of the paint is smoothly stretched and the paint also flows into the bubbles.
[0040]
Thus, the coating liquid film 20 is formed on the surface of the ALC plate 11 so that the inside of the bubbles is coated and there is no unpainted portion.
[0041]
Incidentally, FIG. 3 is a flowchart showing a coating processing procedure of the coating apparatus 10 described above with reference to FIG. As shown in FIG. 2, when the coating apparatus 10 enters the processing procedure from step A1, the ALC plate 11 to be coated moves to step A2.
[0042]
In step A2, the coating apparatus 10 heats the ALC plate 11 by the preheating unit 25, and then proceeds to step A3. From step A3, a coating process is started in the coating unit 30. In step A3, the coating apparatus 10 injects a lump of paint onto the surface of the ALC plate 11 at a high pressure by the spray coating unit 32. Then, the process proceeds to step A4, where an excess of paint is removed by the air cutter 65 in the air blow section 33 to form the paint liquid film 20. Further, the process proceeds to step A5, where the decompression chamber 34 is in a state where there is air that is not completely contained in the paint on the surface of the ALC plate 11, that is, air that is trapped in the air bubbles remaining due to the formation of the paint liquid film 20. The air reservoir in the bubble is expanded by expansion, and the process proceeds to step A6.
[0043]
In step A <b> 6, the coating apparatus 10 sends the ALC plate 11 in a state where the air pockets are repelled in the bubbles and the pinholes are formed to the pressurizing chamber 35, thereby forming the coating liquid film 20 formed on the surface of the ALC plate 11. The air is blown onto the surface of the coating liquid film 20 so that the paint on the surface of the coating liquid film 20 flows into the bubbles to close the pinhole, and the coating liquid film 20 is smoothly stretched. Thus, the coating apparatus 10 dries and cools the coating liquid film in step A7, and ends the coating process for the ALC11.
[0044]
Next, in FIGS. 4 (a), (b), (c), (d) and FIG. 5, the state in which the coating film is formed in the bubbles provided on the surface of the ALC plate 1 will be described in the order of steps. To do. That is, a large amount of coating material 12 is mounted on the surface of the ALC plate 11 by high pressure spraying in the pressure spraying chamber of FIG. 4A (step A3). At that time, the coating material 12 is pushed into the bubbles 3 existing on the surface of the ALC plate 11 from the inlet thereof, and the air is confined inside the bubbles 3 to form the air reservoir 5. In the air blowing chamber of FIG. 5B, high pressure air is ejected from the nozzle, and the excess of the paint 12 mounted on the surface of the ALC plate 11 is removed, and the surface of the ALC plate 11 is removed. A coating liquid film 20 is formed (step A4).
[0045]
Subsequently, since the surface of the coating liquid film 20 applied to the ALC plate 11 is decompressed in the decompression chamber of FIG. 4C, the air reservoir 5 confined in the bubbles 3 as described above. The air expands and ruptures the paint liquid film 20 made of the paint that has been pushed into the inlet in the bubble 3 and is discharged outward. A pinhole 4 is formed in a predetermined portion of the coating liquid film 20 from which the air has been released (step A5).
[0046]
Further, in the pressurizing chamber shown in FIG. 4 (d), high-pressure air is blown from the nozzle onto the coating liquid film 20 on the surface of the ALC plate 11, so that the air confined in the bubbles 3 as described above is released. Then, a part of the coating liquid film 20 around the pinhole 4 flows into the pinhole 4 to close the pinhole 4, and the coating liquid film 20 is formed in this portion. At the same time, the surface of the coating liquid film 20 can be smoothly extended by this air blowing (step A6). Therefore, by carrying out the method of the present invention, as shown in FIGS. 4D and 5, the coating liquid film 20 can be formed so that there is no portion that is not painted on the entire inner surface of the bubble 3. I can do it.
[0047]
FIG. 6A shows a state where the surface of the ALC plate manufactured by carrying out the method of the present invention as described above is photographed with a micrograph. As is apparent from this photograph, it is clear that the coating is filled in the entire surface of many bubbles existing on the surface of the ALC plate, and the coating is also deeply penetrated into the inner wall following the inner peripheral wall of the bubble.
[0048]
6 (b), 7 (a), and 7 (b) are micrographs obtained by photographing the ALC plate cut in the longitudinal direction, respectively, and the inner wall surface of the bubble on the surface of the ALC plate is obtained by this photograph. It is clear that a coating film is formed on the entire surface. In particular, even in the case of the inner bubbles that are separated from the surface of the ALC plate, that is, in the inside of the ALC plate, if the inner bubbles communicate with the bubbles on the surface side, the inner bubbles are also exposed on the entire inner surface of the inner bubbles. It is clear that the paint has penetrated and a coating film has been formed.
[0049]
The paint used for carrying out the above-described apparatus method according to the present invention will be described as follows. That is, the water-based paint that is the undercoat coating composition used in the present embodiment is resin / pigment = 1/10 to 10/10 (solid content weight ratio), and the non-volatile content during coating is 50% or more, # 4 The primer coating composition has a viscosity of 10 to 50 seconds / 25 by a Ford cup and a lamellar length of 3 mm or less. For that purpose, (A) resin, (B) pigment and (C) are dispersed in a solvent, and an acrylic emulsion resin is preferably used as the resin.
[0050]
Examples of the resin that forms the resin coating include water-soluble, water-dispersed (emulsion) -type aqueous resins such as acrylic resins and silicon-modified acrylic resins. Particularly preferred are emulsion resins of acrylic resins or silicon-modified acrylic resins. Used. It can also be used by mixing with a crosslinking material such as hydrazide, glycidyl methacrylate, silanol, oxazoline, metal oxide. Further, these resins are not limited to one type and can be used in combination of two or more types.
[0051]
The undercoat coating composition of the present embodiment preferably has a lamella length of 3 mm or less. The lamella length indicates the degree of liquid breakage in a liquid film such as paint. The smaller the measured value, the easier the liquid film of the paint breaks and the easier it is to remove excess paint by air blowing. When the lamella length exceeds 3 mm, the liquid film of the paint does not break well, and it tends to be difficult to remove the excess paint by air blowing. More preferably, it is 0.1-2 mm.
[0052]
Incidentally, the coating amount and the water permeation amount were compared using an acrylic emulsion type sealer (Audataite 155, manufactured by Nippon Paint Co., Ltd.) as a waterproof coating composition. When a pressure spray shower and an air knife are used according to the method of the present invention (twice treatment), the coating amount of the sealer is 750 to 850 g / m. ² The water permeability was 2 cc / 24 hours or less. On the other hand, in the conventional two-spray spray method, the application amount of the sealer is 2100 g / m. ² Even so, the water permeability was about 4 cc / 24 hours or less. As a method for measuring the water permeability, a method was used in which the funnel was turned upside down and placed on the ALC surface, and the funnel circumference was stopped with a sealer and water was injected.
[0053]
Further, the operation of the coating method of the present invention will be described as follows. That is, in the coating apparatus 10 according to the present invention having the functions and configurations as described above, excess paint is squeezed out of the paint struck by high pressure on the surface of the ALC plate 11 by the air cutter 65. Scrape off. Here, a coating liquid film 20 having a sufficient thickness to secure the properties such as waterproofness inherent to the coating material (coating composition) is secured on the surface of the ALC plate 11. Compared to the case where the extra thickness is secured in response to the occurrence of unpainted bubbles after the air bubbles under the paint liquid film are broken after coating and drying, as in the conventional case. Thin film thickness.
[0054]
The coating liquid film formed with such a thickness is in a state where bubbles in which the paint is not completely contained are generated in the bubbles on the surface of the porous material. By placing the ALC plate 11 formed with a coating liquid film in which bubbles are generated in the decompression chamber 34, the pressure inside the bubbles 3 becomes higher than the pressure in the decompression chamber 34 and is trapped in the bubbles 3. The air in the air reservoir 5 is expanded and repelled.
[0055]
In this way, the surface of the coating liquid film 20 where the air reservoir 5 has repelled is in a state having irregularities such as pinholes 4 at the repelled portion, but such a coating film has not yet been cured. By entering the subsequent pressurizing chamber 35 in such a state, the surface of the coating liquid film 20 is smoothed by the flow of the pressurized air by blowing air, the coating liquid flows into the bubbles, and the coating liquid film 20 with no unpainted remains. It becomes. Thus, on the surface of the ALC plate 11, there is no unpainted bubble 3 that has sufficiently spread over the irregularities (fine holes), and a coating film having a necessary and sufficient thickness is formed.
[0056]
In the above-described embodiment, the ALC plate 11 on which the coating liquid film 20 is formed is placed in the pressurizing chamber 35 in a state where the air reservoir 5 of the bubbles 3 is repelled by the decompression chamber 34. Although the coating liquid film 20 is stretched by the air flowing into the chamber 34, the present invention is not limited to this. For example, air may be blown onto the surface of the coating liquid film 20 using an injection nozzle. The surface of the coating liquid film 20 may be exposed to the air flow.
[0057]
In the above-described embodiment, the case where the recovered paint is filtered using the filter 90 having the configuration shown in FIG. 2 is described, but the present invention is not limited to this, and a filter that filters the recovered paint while stirring, You may make it use the filter of other various structures, such as a filter which makes it easy to filter by adding water to collected paint before filtration.
[0058]
Further, in the above-described embodiment, the flow of air is generated from the pressurizing chamber 35 to the decompression chamber 34 so that the surface of the coating liquid film 20 is uniformly extended. Without providing the chamber 35, the surface of the paint may be extended by the flowing air by allowing the air to flow into the decompression chamber 34 from the external space.
[0059]
【The invention's effect】
In the coating method of the present invention, since the coating material is pressurized and sprayed on the surface of the porous material, the surface of the porous material is coated by pushing the coating material into the bubbles present in the surface of the porous material. The coating liquid film can be formed on the entire surface. In addition, since the coating liquid film surface of the porous material is depressurized after the coating liquid film having a predetermined thickness is formed on the surface of the porous material, the air pool in the bubbles confined by the formation of the coating liquid film is reduced. Is expanded and ruptured, and the air in the bubbles, which is a major cause of the generation of pinholes later, can be discharged and removed in advance.
[0060]
In the method of the present invention, After the paint is sprayed on the surface of the porous material and the paint is applied to the surface, the excess paint adhering to the surface is removed by the removing means. Because Since the thickness of the coating material formed on the surface of the porous material can be kept constant, and the removed coating material can be reused, it has an extremely economical effect. And after expanding and rupturing the air reservoir in the bubbles confined by the formation of the coating liquid film by reducing the pressure of the coating liquid film surface of the porous material, air is sprayed on the surface of the coating liquid film Because The coating liquid film which forms a coating liquid film and still has fluidity is allowed to flow into the entire surface of the bubbles to form a coating film, thereby preventing an unpainted portion from being provided in the bubbles.
[0061]
In the coating apparatus according to the present invention, a pressure spraying apparatus capable of strongly spraying the paint onto the surface of the porous material is provided. Can be pushed in. And it has the effect which can remove the excess coating material apply | coated to the surface of the porous raw material by the removal apparatus. In addition, since a pressure reducing device is provided, the pressure of the surface of the porous material coating liquid film is reduced by this device, so that the air reservoir confined by the formation of the coating liquid film in a large number of bubbles expands and bursts. It also has the effect of being able to be removed from within the bubbles.
[0062]
further, In the device of the present invention, Since an air spraying device is provided separately from the above-mentioned device, the coating liquid is sprayed onto the surface of the porous material by strongly blowing air onto the coating liquid film applied to the surface of the porous material with this device. In addition, it has an effect that a coating film can be formed in the bubbles by flowing into a large number of bubbles.
[Brief description of the drawings]
FIG. 1 is a simplified explanatory view of an apparatus for carrying out a coating method of the present invention.
FIG. 2 is a cross-sectional view of a filter attached to the apparatus of FIG.
FIG. 3 is a flow chart illustrating the method of the present invention.
4 (a), (b), (c), and (d) are cross-sectional explanatory views showing a process of forming a coating film in bubbles on the surface of the ALC plate, respectively.
FIG. 5 shows the present invention. Manufactured by method It is a cross-sectional enlarged explanatory drawing of the principal part of an ALC board.
FIG. 6 (a) shows FIG. FIG. 6B is a micrograph of a longitudinal section of the main part of the ALC plate.
7 (a) and 7 (b) are micrographs of longitudinal sections of main parts of FIG. 6 (a), respectively.
FIG. 8 is an enlarged longitudinal sectional view of the surface of a coated ALC plate of a conventional example.
FIG. 9 (a) is a photomicrograph of the surface of a painted ALC plate of a conventional example. FIG. 9B is a photomicrograph of a longitudinal section on the surface side of a coated ALC plate of a conventional example.
FIG. 10 is an enlarged explanatory view of a longitudinal section of a conventional ALC plate with a large amount of paint applied on the surface thereof.
[Explanation of symbols]
1 ... ALC board
2 ... coating film
3 ... Bubble
4… pinhole
5 ... Air reservoir
10 ... painting equipment
11 ... ALC board
12 ... Paint
20 ... Paint liquid film
22 ... Control unit
25 ... Preheat section
26 ... Sensor
30 ... painted part
32 ... spray painting part
33 ... Air blow part
34 ... decompression chamber
35 ... pressurization chamber
41 ... Shutter
42 ... partition wall
43 ... Bulkhead
44: Bulkhead
46… Recovery tank
51… Piping
52… Pump
53… Hydraulometer
54: Injection nozzle
61… Blower part
62 ... Air distribution chamber
65 ... Air cutter
72: Conveying roller
73 ... Conveying roller
90 ... Filter
91… Case
92 ... wire mesh
95 ... Waste tank
96 ... tank

Claims (2)

In a coating method in which a waterproof coating is formed on the surface of a porous material in which a large number of bubbles are present, the coating material is pressurized and sprayed on the surface of the porous material to apply the coating material in the bubbles of the porous material. Forming a paint liquid film of a predetermined thickness by pressing, removing excess paint on the surface of the porous material with a removing means, and reducing the pressure of the paint liquid film surface of the porous material to form a paint liquid film Forming a coating film by expanding and rupturing the air reservoir in the bubble confined by the above, and blowing the air onto the surface of the coating liquid film to cause the coating liquid to flow into the entire surface of the bubble to form a coating film. A characteristic method of painting porous materials.   In a coating device that forms a waterproof coating on the surface of a porous material containing a large number of bubbles, pressure is applied to the surface of the porous material by spraying the coating material into the bubbles. A spraying device, a removing device that removes excess paint, and a vacuum that expands and ruptures an air reservoir confined by the formation of a coating liquid film in the bubbles by depressurizing the surface of the porous material coating liquid film A porous material coating apparatus comprising a combination of an apparatus and an air spraying apparatus for causing a coating liquid to flow into the bubbles by spraying air onto the surface of the coating liquid film.

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