JP2000044365A - Coating of surface of aerated lightweight concrete - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for coating the surface of aerated lightweight concrete(ALC), capable of saving the wasteful use of a coating and allowing the applied coating to exhibit a high adhesive force to the ALC substrate. SOLUTION: Water is sprayed on an ALC substrate 1 having designed grooves 1a, 1b and countless depressions and projections on the surface by the use of a spray gun 3. A curtain-like coating having a uniform thickness is allowed to flow down on the surface of the ALC substrate 1 by the use of a curtain flow coater 4 to coat the surface with the coating. The excessive coating on the surface is moved into the grooves 1a, 1b with air blow from nozzles 5 to form the uniform coating film. When a wind-wrought pattern is generated by the air blow, the surface is again coated using the curtain flow coater after the air blow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for coating a lightweight cellular concrete surface, which can improve the performance of a coating film including appearance when painting the surface of the lightweight cellular concrete.

[0002]

2. Description of the Related Art Lightweight cellular concrete (hereinafter "ALC")
Panels and precast concrete (P
C) Panels are increasingly used as panels for building outer walls. Since the panels for these outer walls are directly affected by the weather and the temperature, when they are used in a building, their surfaces are generally painted with a predetermined water permeability.

[0003] When coating the surface of ALC or PC, there is a method of spraying and applying the paint with a spray gun. According to this method, the particles of the coating material can enter into the countless irregularities formed on the surface of the ALC substrate to form a coating film having a high adhesive force. However, in gun spray painting,
There is a problem that the coating efficiency of the paint is low and the amount of paint consumed per unit area increases.

[0004] A coating method called a curtain flow coater is also practiced in which a panel made of ALC or PC is laid flat and an emulsion type paint is freely dropped in a curtain form from above to paint. In this method, since the emulsion type paint is applied in a thin film form to the panel surface, it is excellent in concealment of the surface, and the amount of paint used to obtain the necessary water permeability is smaller than that of the spray gun coating method. It has the advantage of being significantly less.

[0005]

The surface of the ALC substrate is formed with innumerable fine irregularities of about 0.5 mm. Since the paint naturally falls by the coating method using the curtain flow coater, the paint has a small irregularity. It does not penetrate inside (poor wettability) and cannot be said to have high adhesion. For this reason,
When expansion and contraction repeatedly act on the ALC substrate, there is a possibility that the coating film may be cracked or peeled off.

In a curtain flow coater, the amount of paint supplied per unit length is constant. For this reason, when the design grooves are formed on the surface of the ALC base material, for example, vertically and horizontally, the amount of the paint supplied to the inclined surface forming the grooves is determined by the amount of the paint supplied to the flat surface. And there is a problem that it is difficult to form a coating film having a uniform thickness on the entire surface.

[0007] An object of the present invention is to provide a method for coating an ALC surface capable of realizing high adhesion to the surface of the ALC substrate and forming a coating film having a uniform thickness on the surface of the ALC substrate. Is to do.

[0008]

In order to solve the above-mentioned problems, a method for coating an ALC surface according to the present invention comprises applying an aqueous paint using a curtain flow coater after the ALC surface is wetted with water. It is a feature.

In the above-mentioned coating method, the ALC surface is wetted with water prior to coating the ALC surface with the curtain flow coater, so that the water can be used as a medium to apply the paint even with the curtain flow coater. It sufficiently enters and attaches to the myriad of irregularities formed on the ALC surface. As a result, the formed coating film can exhibit high adhesion to the surface of the ALC.

In the above method for coating the surface of ALC, AL
When a groove is formed on the C surface, it is preferable to blow air on the surface of the paint applied by the curtain flow coater to make the coating film of the groove uniform, and after air blowing,
Further, it is preferable to apply a paint by a curtain flow coater.

In the above-mentioned coating method, when grooves are formed on the ALC surface, air is blown onto the grooves where there is a risk that the curtain flow coater alone may cause unpainted portions and insufficient film thickness, so that the surface is excessively blown. Since the paint is supplied, it is possible to form a coating film having a sufficient thickness on the groove, particularly on the inclined surface, and having the same thickness as the flat portion.
For this reason, A with a design consisting of deeply carved grooves on the surface
Even with LC, sufficiently high water permeability can be obtained with a small amount of paint.

[0012] Further, after air is blown onto the ALC surface to remove excess paint, a coating film is formed again by a curtain flow coater, so that even when a wind ripple is formed by air blowing, the wind ripple is reduced. A good surface can be obtained by concealment.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the method for coating the surface of an ALC will be described below with reference to the drawings. FIG.
FIG. 2 is a perspective view illustrating an example of an apparatus for realizing an ALC surface coating method according to the present invention, and FIG. 2 illustrates a state of a coating film when the ALC surface is wetted with water and then coated by a curtain flow coater. FIG.

According to the method for coating the ALC surface according to the present invention, first, the ALC surface is wetted with water, and then the coating is performed with a curtain flow coater, thereby forming a unique fine surface formed on the surface of the ALC substrate. Fill the paint into the irregularities (about 0.5mm)
This achieves an improvement in the adhesion to the C base material and further satisfies predetermined water permeability.

In this embodiment, as shown in FIG.
The LC base material 1 is formed in a panel shape and has grooves 1a and 1b on the surface. This ALC substrate 1
Is placed on the roller conveyor 2 and transported at a predetermined speed in the direction of arrow a.

A spray gun 3 is arranged upstream of the ALC substrate 1 in the transport direction, a curtain flow coater 4 is arranged downstream of the spray gun 3, and a nozzle 5 for air blowing is arranged further downstream. I have. Accordingly, a series of operations including the spraying of water by the spray gun 3, the coating by the curtain flow coater 4, and the air blowing by the nozzle 5 are performed in the process of transporting the ALC substrate 1.

In the first step of spraying water on the ALC substrate 1 by the spray gun 3, water supplied at a predetermined pressure to the spray gun 3 is atomized by a spray nozzle provided on the spray gun 3. By spraying while forming fine water droplets, the entire surface including the grooves 1a and 1b and the uneven portion 1c of the surface formed on the surface of the ALC substrate 1 is uniformly wetted.

ALC sprayed by the spray gun 3
Water adhering to the surface of the substrate 1 immediately permeates into the ALC substrate 1. For this reason, it is necessary to manage conditions such as the amount of water sprayed and the time from when the water is sprayed to when the coating is performed by the curtain flow coater 4, together with the transport speed by the roller conveyor 2.

In the experiments of the present inventor, the amount of water sprayed was preferably about 0.1 kg to 0.8 kg per square meter.
If the amount is smaller than the above-mentioned amount, the effect of mediating the adhesion of the paint applied by the curtain flow coater 4 is reduced, that is, the applied paint can enter the uneven portion 1c formed on the surface of the ALC substrate 1. There is no case. If the amount is larger than the above-mentioned amount, the coating material applied by the curtain flow coater 4 penetrates into the ALC substrate 1 together with water, and it becomes impossible to obtain the desired coating performance.

It is preferable that the time from spraying the water to coating with the curtain flow coater 4 is about 0 minute (painting immediately after water spraying) to several minutes. If the time is longer than the above, the water sprayed on the surface of the ALC substrate 1 permeates into the inside, and the water spraying effect is lost. However, it is possible to extend the time to some extent by increasing the amount of water sprayed.

The curtain flow coater 4 is an ALC substrate 1
The second step in the surface coating is carried out, and the water-based paint is caused to flow down from the coater head 4a in a curtain shape having a uniform thickness. As shown in FIG. 2, a coating film 6 having a uniform thickness is formed on the upper surface of the water film sprayed by the gun 3.

The aqueous paint flowing down from the coater head 4a of the curtain flow coater 4 includes acrylic emulsion paints such as acrylic resin, vinyl acetate emulsion paints, urethane emulsion paints, olefin emulsion paints and the like. It is possible to use paint selectively. The water-based paint used for the curtain flow coater 4 needs to have high fluidity.

The water-based paint flowing down from the coater head 4a is immersed in the surface of the ALC
And flows down from both sides of the roller conveyor 2 and is stored in a paint tank 8 through a paint receiving gutter 7 arranged below the roller conveyor 2. A circulation pump 9 is connected to the paint tank 8, and the circulation pump 9 and the coater head 4a are connected to a filter.
It is connected by a pipe 12 having 11.

In the curtain flow coater 4, AL
When the coating on the C base material 1 is performed, when the circulation pump 9 is driven, the water-based paint stored in the paint tank 8 is pumped and passed through the filter 11 to remove impurities such as dust, and then, from the coater head 4a. The A that has flowed down to the surface of the ALC substrate 1 and is wet by the water already sprayed.
A coating film 6 having a uniform thickness is formed on the surface of the LC substrate 1. At this time, the grooves 1a, 1a formed in the ALC substrate 1
The water-based paint flows down in a curtain shape having a uniform thickness also in b, and the coating film 6 is also formed on the slopes forming the grooves 1a and 1b.

In the curtain flow coater 4, since the paint flows down in the state of a liquid film without spraying, the paint does not scatter at the time of painting. Therefore, it is possible to recover 90% to 100% of the supplied water-based paint without any loss due to the scattering of the paint.

The water-based paint that has flowed down from the coater head 4a is not urged and does not forcibly collide with the surface of the ALC substrate 1. Therefore, the water-based paint may normally enter a concave portion formed on the surface of the ALC substrate 1. Absent. However, since the surface of the concave portion is wet with the water already sprayed, it becomes possible to form the coating film 6 having a high adhesive force by entering the concave portion through the water.

The surface of the ALC substrate 1 has grooves 1a,
1b, the first surface does not have the first surface.
Through the step and the second step, it is possible to realize a coating having a high adhesive force on the surface of the ALC substrate 1. However, the grooves 1a,
In the case where the groove 1b is formed, there is a possibility that, in particular, the groove 1a or 1b may be left uncoated or the coating film thickness may be insufficient.

Therefore, the ALC substrate 1 on which the coating film 6 is formed by the curtain flow coater 4 as described above.
Then, the third step of the painting operation is performed. In this step, excess paint on the surface of the ALC substrate 1 is removed by compressed air injected from the nozzle 5 and supplied to the grooves 1a and 1b. The coated film 6 is finished to a smooth surface without excess paint stagnation.

The air blow nozzles 5 are arranged in two rows in a direction transverse to the roller conveyor 2, and each row has a predetermined angle with respect to the direction of transport of the ALC substrate 1 by the roller conveyor 2. ing. The nozzles 5 in each row are configured so that the height, position, and the like can be adjusted according to the shape and depth (design) of the grooves 1a and 1b formed on the surface of the ALC substrate 1. The compressed air supplied from a compressed air supply source such as an air compressor (not shown) is equalized in pressure in the air blow header 5a, and is injected from the nozzle 5 attached to the air blow header 5a under uniform pressure. You.

The entire surface of the ALC substrate 1 including the grooves 1a and 1b on the design is continuously applied to the surface of the ALC substrate 1 by the coating and air blowing of the first to third steps. Coating film 6 with high adhesion and uniform thickness
It is possible to obtain a predetermined water permeability with the coating film 6 with a small amount of paint.

When the compressed air is sprayed on the surface of the ALC substrate 1, the paint on the surface of the ALC substrate 1 is immediately after being applied, so that excess paint on the surface is removed.
A streamline (wind ripple) of the paint may be formed due to the injection of the compressed air. In this case, drying in the above state, ALC
There is a possibility that the appearance of the painted surface of the base material 1 is impaired.

For this reason, after air blowing with the nozzle 5, an aqueous paint having a uniform thickness and flowing down in a curtain shape is applied again to the surface of the ALC substrate 1 by a curtain flow coater (not shown) (fourth step). )are doing. In this embodiment, it was possible to obtain a sufficient aesthetic appearance by applying 0.4 kg of the water-based paint per square meter.

In particular, when the water-based paint is caused to flow down on the surface of the ALC substrate 1 by the curtain flow coater after air blowing with the nozzle 5, as described above, the water-based paint that has flowed down is forcibly applied to the surface of the ALC substrate 1. Since it does not collide with the ALC substrate 1, it does not enter into the concave portion formed on the surface of the ALC substrate 1. For this reason, it becomes possible to cover the upper part of the countless irregularities 1c formed on the surface of the ALC substrate 1 flat, and to conceal the irregularities 1c simultaneously with the concealment of the wind ripples.

As described above, the coating film cannot exert a sufficiently high adhesive force to ALC only by coating with a normal curtain flow coater. On the other hand, in the present invention, the ALC substrate 1 is sprayed with water in advance. By using the water as a medium, it is possible to realize a high adhesion of the coating film 6 made of the water-based paint flowing down from the curtain flow coater 4.

[0035]

As described in detail above, in the method for coating the ALC surface according to the present invention, first, water is sprayed on the entire surface including the myriad of irregularities formed on the ALC surface, whereby the ALC surface is sprayed. Wet and apply the water-based paint in a curtain with a uniform thickness using a curtain flow coater.
High adhesion to the C base material can be realized.

When a design groove is formed on the surface of the ALC, compressed air is blown in a subsequent step of the curtain flow coater, so that the curtain flow coater does not have a sufficient coating film to form a sufficient groove. A paint can be supplied to form a required coating film.

Further, after the compressed air is blown on the ALC surface, by applying the coating again by the curtain flow coater, the wind ripple which may be generated by the air blow can be eliminated, and the ALC surface is formed. Innumerable irregularities can be hidden.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an example of an apparatus that realizes a method for coating an ALC surface according to the present invention.

FIG. 2 is a view for explaining a state of a coating film when coating with a curtain flow coater is performed subsequent to water spraying with a spray gun.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ALC base material 1a, 1b Groove 1c Concavo-convex part 2 Roller conveyor 3 Spray gun 4 Curtain flow coater 4a Coater head 5 Nozzle 5a Air blow header 6 Coating film 7 Paint trough 8 Paint tank 9 Circulation pump 11 Filter 12 Piping

Claims (3)

[Claims] 1. A method for coating a lightweight cellular concrete surface, which comprises applying a water-based paint with a curtain flow coater after the surface of the lightweight cellular concrete is wetted with water. 2. The groove according to claim 1, wherein a groove is formed on the surface of the lightweight cellular concrete, and air is blown onto the surface of the paint applied by the curtain flow coater to make the coating film in the groove uniform. How to paint lightweight cellular concrete surface. 3. A paint is further applied by a curtain flow coater after air blowing.
The method for coating the lightweight cellular concrete surface described in the above.