JP6912836B1 - A method of applying a foaming airless coating agent on an existing coating film to peel it off. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the release agent from scattering when the release agent is applied, and to prevent the release agent applied on the surface of an existing coating film from dripping from the existing coating film. It is possible to increase the coating film thickness and thus the coating amount at the same time. By using an airless spray gun 50 having a nozzle 92, the release agent 20 itself is pressurized and the release agent 20 is ejected from the nozzle 92 without using compressed air, whereby a plurality of release agents 20 are used. Divide into droplets. The sprayed release agent 20 is applied onto the coating film surface 14, and upon the application, a plurality of droplets of the release agent 20 collide with the coating film surface, whereby the plurality of droplets are each in the atmosphere. Air is entrained and foamed, whereby the release agent 20 is applied onto the coating film surface 14 in a foamed state. After the required time has elapsed from the completion of the coating, the existing coating film 14 softened by the release agent 20 is physically peeled from the structure 12. [Selection diagram] Fig. 1

Description

The present invention relates to a technique for wet-peeling an existing coating film from a structure using a release agent, and in particular, preventing the release agent from scattering when the release agent is applied and the surface of the existing coating film. The present invention relates to a technique that enables the release agent applied above to simultaneously increase the coating film thickness and thus the coating amount of the release agent without dripping from the existing coating film.

Conventionally, in order to repaint the surface of structures such as buildings (houses, buildings, etc.), civil engineering structures (bridges, etc.), ships, vehicles (automobiles, trains, etc.), airplanes, etc., they have already been adhered to the surface. A type of construction is performed in which the existing coating film is peeled off from the surface of the structure and then a new paint is applied on the same surface of the structure.

Here, as a method for peeling off the existing coating film, for example, as described in Patent Document 1, there are a physical method and a chemical method. The physical method is a method in which an operator uses a hand tool such as a scraper, an electric tool or a rotary tool such as a wire brush, a peeling machine such as a high-pressure water injector, or the like to peel off an existing coating film from a structure.

On the other hand, the chemical method is a method in which a release agent containing a chemical is applied to an existing coating film to dissolve or swell the existing coating film, thereby peeling the existing coating film from the structure. This method is also referred to as a wet coating film removing method using a coating film removing agent, that is, a wet peeling method, as described in Patent Document 1, for example.

There are various demands for the wet peeling method. For example, a request that the release agent has a small adverse effect on the environment (improvement of environmental response ability), a request that the release agent has a small adverse effect on the health of the worker (prevention of damage to the health of the worker), work There is a demand for high efficiency when a person performs a peeling work (improvement of the peeling work of a worker), a demand for a high ability of a peeling agent to peel an existing coating film (improvement of peeling performance of a peeling agent), etc. do.

Regarding the wet peeling method, Patent Document 1 describes the film thickness of the peeling agent layer (hereinafter, also referred to as “peeling agent layer” or “peeling agent coating film”) to be adhered on the existing coating film (hereinafter, “removing agent coating film”). For the purpose of increasing the "coating film thickness"), a surfactant is added to the release agent as a foaming agent before dipping the release agent, and the release agent is stirred in that state to form a release agent. It discloses a technique for mixing minute bubbles. If the coating thickness of the release agent applied on the existing coating film is increased by dipping and the coating amount is increased, there is a possibility that the demands for improving the efficiency of the peeling work and the peeling performance may be satisfied.

Further, Patent Document 2 discloses a technique of using an airless spray coating machine in order to expand the coating area of the release agent. However, Patent Document 2 does not disclose or suggest that it is useful to use an airless spray coating machine to increase the coating thickness of the release agent.

Japanese Unexamined Patent Publication No. 62-20575 Japanese Patent No. 6442101

Against the background of the above-mentioned prior art, the present inventor has the above-mentioned four requests, that is, a request for improving the environmental response ability, a request for preventing health damage to the worker, and a request for improving the efficiency of the peeling work. In order to simultaneously achieve at least two of the demands for improving the peeling performance of the release agent, the release agent should not be scattered when the release agent is applied, and the release agent is applied on the surface of the existing coating film. I realized that it is important to increase the coating film thickness and thus the coating amount of the release agent without dripping from the existing coating film at the same time.

Then, the present inventor uses the wet release agent coating technique to prevent the release agent from scattering when the release agent is applied, and to allow the release agent applied on the surface of the existing coating film to drip from the existing coating film. Research and development was carried out to make it possible to maximize the coating film thickness of the release agent and increase the coating amount and thus the coating amount at the same time.

Against these circumstances, the present invention is a wet release agent coating technique, which prevents the release agent from scattering when the release agent is applied and a release agent applied on the surface of an existing coating film. However, it has been an object of the present invention to provide a material capable of simultaneously increasing the coating film thickness and the coating amount of the release agent without dripping from the existing coating film.

In order to solve the problem , according to the first aspect of the present invention, it is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle, whereby the release agent is divided into a plurality of droplets and collides with the surface of the coating film. Injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
A coating film peeling method including the above is provided.
Further, according to the second aspect of the present invention, it is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle, whereby the release agent is divided into a plurality of droplets and collides with the surface of the coating film. Injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
Including
The spraying step provides a coating film peeling method in which the release agent is sprayed from the nozzle so that the average particle size of the plurality of droplets when colliding with the surface of the coating film is larger than 50 μm.
Further, according to the third aspect of the present invention, it is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle, whereby the release agent is divided into a plurality of droplets and collides with the surface of the coating film. Injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
Including
The viscosity of the release agent, the injection pressure when the release agent is ejected from the nozzle, and the average diameter of the nozzle are the average particle diameters of the plurality of droplets when they collide with the coating film surface. A coating film peeling method set to be larger than 50 μm is provided.
Further , according to the first aspect of the present invention, it is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle, whereby the release agent is divided into a plurality of droplets and collides with the surface of the coating film. Injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
The release agent is applied to at least one of the viscosity of the release agent, the injection pressure when the release agent is ejected from the nozzle, and the average diameter of the nozzle using the airless spray gun. Provided is a coating film peeling method including a condition setting step of setting the atomizing property of the stripping agent to be poor.

Further, according to the second aspect of the present invention, it is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
An injection step of injecting the release agent using an airless spray gun to divide it into a plurality of droplets.
The smaller the surface roughness of the existing coating film, the smaller the surface roughness of the coating film to be formed by applying the sprayed release agent onto the surface of the coating film and the coating agent on the surface of the coating film. A coating film peeling method including a coating step of coating so as to have a large coating film thickness is provided.

According to the present invention, the following aspects can be obtained. Each aspect shall be divided into sections, each section shall be numbered, and the numbers of other sections shall be cited as necessary. This is to facilitate understanding of some of the technical features that can be adopted by the present invention and combinations thereof, and the technical features that can be adopted by the present invention and combinations thereof are limited to the following aspects. Should not be interpreted as. That is, it should be interpreted that it is not hindered from appropriately extracting and adopting the technical features described in the present specification as the technical features of the present invention, which are not described in the following aspects.

Furthermore, describing each section in the form of quoting the numbers of the other sections does not necessarily prevent the technical features described in each section from being separated and independent from the technical features described in the other sections. It does not mean, and it should be interpreted that the technical features described in each section can be made independent as appropriate according to their properties.

(1) A method of wet-peeling an existing coating film from a structure using a release agent.
By using airless spray gun having a nozzle, the release agent itself pressurized by injecting the release agent from the nozzle, whereby the injection step of dividing the release agent into a plurality of droplets,
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the release agent is applied on the surface of the coating film in a foamed state.
A coating film peeling method including a peeling step of physically peeling an existing coating film softened by the release agent from the structure after a lapse of a required time from the completion of the coating.

(2) The coating film peeling method according to item (1), wherein the release agent has a high viscosity.

(3) The coating film peeling method according to item (1) or (2), wherein the stripping agent is an aqueous stripping agent emulsion in which a main component and water are emulsified using a surfactant.

(4) The coating film peeling method according to item (1) or (2), wherein the release agent is a solvent-based release agent.

(5) In the coating step, the release agent is applied to the surface of the coating film so that the release agent in the foamed state has a plurality of bubbles having an average diameter in the range of about 0.1 mm to about 0.5 mm. The coating film peeling method according to any one of (1) to (4), which is applied above.

(6) In the coating step, the release agent is applied to the surface of the coating film so that the average coating film thickness of the coating film formed by applying the release agent onto the surface of the coating film is about 1 mm. The coating film peeling method according to any one of (1) to (5), which is applied above.

(7) In the coating step, the coating film is formed by applying the release agent onto the surface of the coating film so that the average coating film thickness is in the range of about 2 mm to about 5 mm. The coating film peeling method according to any one of (1) to (5), wherein the release agent is applied onto the surface of the coating film.

(8) In the coating step, the coating film formed by the release agent being applied onto the surface of the coating film has a larger coating film thickness as the surface roughness of the existing coating film is smaller. The coating film peeling method according to any one of (1) to (7), wherein the release agent is applied onto the surface of the coating film.

(9) In the injection step, the release agent is pressurized with an injection pressure having a height that changes according to the viscosity of the release agent and the discharge amount of the release agent from the nozzle, and the release agent is injected from the nozzle. The coating film peeling method according to any one of 1) to (8).

(10) The release agent is volatile and has
The coating film peeling method further
After the application of the release agent is completed, the coating film surface is wrapped with a protective sheet that is impermeable to the release agent, whereby the vaporized gas generated from the release agent is released from the coating film surface to the atmosphere. Includes a wrapping process to prevent
The coating film peeling method according to any one of (1) to (9), wherein the peeling step includes a step of peeling the protective sheet from the existing coating film after the required time has elapsed.

(11) The injection step does not include a step of bringing the release agent into contact with the flow of compressed air and atomizing the release agent by the principle of spraying, and further, the release agent is said before being injected from the nozzle. The method for removing a coating film according to any one of (1) to (10), which does not include a step of foaming a release agent.

(21) A method of wet-peeling an existing coating film from a structure using a release agent.
The release agent has a high viscosity of more than 0.1 Pa · s and has a high viscosity.
The method is
By using airless spray gun having a nozzle, the release agent itself pressurized by injecting the release agent from the nozzle, whereby said release agent is impinging on the coating film surface is divided into a plurality of droplets Injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. A coating film peeling method comprising a method in which each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.

(22) The coating film peeling method according to item (21), wherein the peeling agent has a viscosity not exceeding 16 Pa · s (20 ° C.).

(23) The coating film peeling method according to (21) or (22), wherein the release agent is an aqueous release agent emulsion in which a main component and water are emulsified using a surfactant.

(24) The coating film peeling method according to item (21) or (22), wherein the stripping agent is a solvent-based stripping agent.

(25) The coating film peeling method according to any one of (21) to (24), wherein the injection step injects the release agent from the nozzle at an ^{injection pressure not exceeding 80 kg / cm 2.}

(26) In the coating step, the peeling is performed so that the average coating film thickness of the coating film formed by the release agent being applied onto the surface of the coating film without recoating is not less than about 1 mm. The coating film peeling method according to any one of (21) to (25), wherein the agent is applied onto the surface of the coating film.

(27) In the coating step, the average coating film thickness of the coating film formed by applying the release agent onto the coating film surface without recoating is within the range of about 2 mm to about 5 mm. The coating film peeling method according to any one of (21) to (25), wherein the release agent is applied onto the surface of the coating film.

(28) The coating film peeling according to any one of (21) to (27), wherein in the coating step, the release agent is applied onto the coating film surface so as to have a coating amount of ^{1.0 kg / m 2.} Method.

(29) In the injection step, the release agent is pressurized with an injection pressure having a height that changes according to the viscosity of the release agent and the discharge amount of the release agent from the nozzle, and the release agent is injected from the nozzle (29). 21) The coating film peeling method according to any one of items (28) to (28).

(30) The release agent is volatile and has
The coating film peeling method further
After the application of the release agent is completed, the coating film surface is wrapped with a protective sheet that is impermeable to the release agent, whereby the vaporized gas generated from the release agent is released from the coating film surface to the atmosphere. The wrapping process to prevent it from being done,
Any of (21) to (29), which includes a peeling step of peeling the protective sheet from the existing coating film after a lapse of a predetermined time, and further peeling the existing coating film softened by the release agent from the structure. The coating film peeling method described in Crab.

(31) The injection step does not include a step of bringing the release agent into contact with the flow of compressed air and atomizing the release agent by the principle of spraying, and further, before injecting the release agent from the nozzle. The coating film peeling method according to any one of (21) to (30), which does not include a step of foaming the release agent.

(51) A method of wet-peeling an existing coating film from a structure using a release agent.
The method is
By using airless spray gun having a nozzle, the release agent itself pressurized by injecting the release agent from the nozzle, whereby said release agent is impinging on the coating film surface is divided into a plurality of droplets Injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
At least one of the viscosity of the release agent, the injection pressure when the release agent is ejected from the nozzle, and the average diameter of the nozzle is sprayed with the release agent using the airless spray gun. A coating method that is set so that the atomizing property of the release agent is deteriorated.

(52) The coating according to item (51), wherein at least one of the viscosity, the injection pressure, and the average diameter is set so that the average particle size of each of the plurality of droplets is larger than 50 μm. Film peeling method.

(53) The coating film peeling method according to item (51) or (52), wherein the viscosity is set to a value higher than 0.1 Pa · s (20 ° C.).

(54) The coating film peeling method according to any one of (51) to (53), wherein the injection pressure is ^{set to a height not exceeding 80 kg / cm 2.}

(55) The coating film peeling method according to any one of (51) to (54), wherein the equivalent diameter is set to a value of 0.4 mm or more.

(56) The coating film peeling method according to any one of (51) to (55), wherein the viscosity is set to a value not exceeding 16 Pa · s (20 ° C.).

(57) In the coating step, the peeling is performed so that the average coating film thickness of the coating film formed by the release agent being applied onto the surface of the coating film without recoating is not less than about 1 mm. The coating film peeling method according to any one of (51) to (56), wherein the agent is applied onto the surface of the coating film.

(58) In the coating step, the average coating film thickness of the coating film formed by applying the release agent onto the coating film surface without recoating is within the range of about 2 mm to about 5 mm. The coating film peeling method according to any one of (51) to (57), wherein the release agent is applied onto the surface of the coating film.

(59) The coating film peeling according to any one of (51) to (58), wherein in the coating step, the release agent is applied onto the coating film surface so as to have a coating amount of ^{1.0 kg / m 2.} Method.

(60) In the injection step, the release agent is pressurized with an injection pressure having a height that changes according to the viscosity of the release agent and the discharge amount of the release agent from the nozzle, and the release agent is injected from the nozzle (60). 51) The method for peeling a coating film according to any one of items (59) to (59).

(61) The release agent is volatile and has
The coating film peeling method further
After the application of the release agent is completed, the coating film surface is wrapped with a protective sheet that is impermeable to the release agent, whereby the vaporized gas generated from the release agent is released from the coating film surface to the atmosphere. The wrapping process to prevent it from being done,
After a lapse of a predetermined time, any of (51) to (60) including a peeling step of peeling the protective sheet from the existing coating film and further peeling the existing coating film softened by the release agent from the structure. The coating film peeling method described in Crab.

(62) The injection step does not include a step of bringing the release agent into contact with the flow of compressed air and atomizing the release agent by the principle of spraying, and further, before injecting the release agent from the nozzle. The method for removing a coating film according to any one of (51) to (61), which does not include a step of foaming a release agent.

(63) A method of wet-peeling an existing coating film from a structure using a release agent.
The method is
An injection step of injecting the release agent using an airless spray gun to divide it into a plurality of droplets.
The smaller the surface roughness of the existing coating film, the smaller the surface roughness of the coating film to be formed by applying the sprayed release agent onto the surface of the coating film and the coating agent on the surface of the coating film. A coating film peeling method including a coating step of applying so as to have a large coating film thickness.

(64) In the coating step, the release agent is made to collide with the coating film surface as the plurality of droplets, whereby the plurality of droplets are entrained with air in the atmosphere and foamed, whereby the plurality of droplets are foamed. The coating film peeling method according to item (63), wherein the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
(65) A method of wet-peeling an existing coating film from a structure using a release agent.
The release agent has a high viscosity of more than 0.1 Pa · s and has a high viscosity.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle, whereby the release agent is divided into a plurality of droplets and collides with the surface of the coating film. Injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
Coating film peeling method including.

FIG. 1 is a system diagram conceptually representing an exemplary airless coating machine used to carry out a coating film stripping method according to an exemplary embodiment of the present invention. FIG. 2 is a table showing the composition and operating temperature of each of a plurality of types of release agents, that is, removers, which are selectively used in the airless coating machine shown in FIG. FIG. 3 is a process diagram showing an exemplary preparatory step in the coating film peeling method. FIG. 4 is a process diagram showing an exemplary construction process in the coating film peeling method. FIG. 5 is a diagram conceptually showing the temporal transition of the properties of the remover ejected from the nozzle of the airless spray gun shown in FIG. FIG. 6 is a diagram showing the test results of the coatability of a remover applied on an existing coating film according to an embodiment of the present invention in comparison with a comparative example. FIG. 7A shows the viscosity of the release agent before being sprayed from the airless spray gun when the liquid release agent is airlessly applied, and the particle size of each of the plurality of droplets in which the release agent is divided by the spray. It is a graph conceptually showing a general relationship established between (for example, average diameter) and atomization property of a release agent by an airless spray gun, and FIG. 3B is an airless graph in the same spray environment. 6 is a graph conceptually showing a general relationship established between the injection pressure of a release agent from a spray gun and the particle size of each of the droplets. FIG. 8 shows an average coating which is the thickness of the film to which the release agent should be applied on the surface of the existing coating film according to the surface roughness of the existing coating film when the coating film peeling method according to the above embodiment is carried out. It is a graph which conceptually shows an example of the process which determines the film thickness.

Hereinafter, a more specific exemplary embodiment of the present invention will be described in detail with reference to the drawings.

An exemplary embodiment of the present invention relates to a wet peeling method for stripping an existing coating film from a structure (or a structure) using a stripping agent (hereinafter, also referred to as “remover”). Specifically, the wet peeling method is a foaming airless coating peeling method in which a peeling agent is applied onto an existing coating film by foaming airless (airless injection, airless spraying) to peel off.

An example of the foaming type airless coating peeling method is a method of applying a foaming airless coating on an existing coating film and peeling.

Here, "high viscosity" means, for example, a viscosity higher than the viscosity limit (for example, 0.1 Pa · s (20 ° C.)) at which general coating is possible when expressed in terms of paint viscosity. For example, "high viscosity" means a viscosity corresponding to gel coat paint (3 Pa · s (20 ° C.)) or higher, or a viscosity corresponding to mayonnaise (23 ° C.) (8 Pa · s (20 ° C.)). )) Or higher viscosity may be meant.

Another example of the foaming airless coating peeling method is a method in which a highly viscous and emulsified stripping agent is coated on an existing coating film by foaming airless coating and peeled. An example of a highly viscous and emulsified release agent is the first remover shown in FIG. 2, as will be described later.

The above-mentioned foaming airless coating peeling method (hereinafter, referred to as “main peeling method”) includes a foaming airless coating step S201 as a chemical peeling step and a physical method, as will be described in detail later with reference to FIG. The peeling step S203 as a specific (mechanical) peeling step is provided as a plurality of steps carried out in the order thereof.

FIG. 1 conceptually shows an exemplary airless coating machine 10 used for carrying out the foam-type airless coating step S201 described above in a system diagram.

The airless coating machine 10 includes a tank 30 for storing a release agent 20 applied on the existing coating film 14 in order to wetly peel the existing coating film 14 from the structure 12, and an airless type pump 40 (pumping machine). And an airless spray gun (hereinafter, simply referred to as "spray gun") 50, and an air compressor 60 as a drive source of the pressure feed pump 40.

Specifically, the air compressor 60 applies a high pressure to the pressurizing chamber 76 located behind the plunger or piston, which will be described later, thereby causing a discharge chamber (high viscosity to be discharged) located in front of the plunger or piston. 20 is used to pressurize the room 80 from which the release agent 20 is fed from the tank 30.

The airless spray method using the spray gun 50 will be described in detail later with reference to FIG. 5, but briefly explained, a high pressure is applied to the release agent 20 to form a liquid film, and the liquid film is formed into the atmosphere (static air). This is a method of atomizing the release agent 20 into droplets.

The tank 30 is connected to the supply port 72 of the pump 40 via a hose 70. The supply port 72 is fluidly connected to the discharge port 80. The air compressor 60 is connected to the pressurizing chamber 76 of the pressure feed pump 40 via the air hose 74. The spray gun 50 is connected to the discharge chamber 80 of the pressure feed pump 40 via a high pressure hose 78. In the airless coating machine 10, the hose 70 constitutes a supply line, the air hose 74 constitutes a compressed air line, and the high pressure hose 78 constitutes a pumping line.

The spray gun 50 pressurizes the release agent 20 itself by the plunger or the piston and injects the release agent 20 from the nozzle without bringing the compressed air into direct contact with the release agent 20, thereby causing the release agent 20 to be plurality. It is configured to be divided into droplets of.

<Setting of spray factor>

In the present embodiment, the spray factor, that is, the viscosity of the release agent 20, the injection pressure when the release agent 20 is ejected from the nozzle (“atomization pressure”), and the average diameter of the nozzle. At least one is set so that the atomizing property of the release agent 20 when the release agent 20 is sprayed using the airless spray gun 50 is deteriorated.

The reason for setting the spray factor so that the atomizing property of the release agent 20 is deteriorated will be described in detail later, but will be briefly described as follows.

That is, when the atomizing property of the release agent 20 is deteriorated, the average particle size of each of the plurality of droplets in which the release agent 20 is divided by spraying is good in atomizing property. Become larger. On the other hand, the larger the average particle size, the larger the momentum (= mv) of each droplet when each droplet flies in the static air, and the higher the ability to penetrate the static air, and as a result, each liquid. The flight speed of the droplets is faster than when each droplet is small. As a result, the impact energy (collision energy) when each droplet collides with the surface of the existing coating film 14 becomes larger than when the atomization property is good.

FIG. 7A shows the viscosity of the release agent 20 before being sprayed from the airless spray gun 50 when the liquid release agent 20 is airlessly applied, and the plurality of droplets in which the release agent 20 is divided by the spray. The general relationship established between each particle size (for example, the average diameter) and the atomization property of the release agent 20 by the airless spray gun 50 is conceptually represented by a graph.

Specifically, the higher the viscosity, the larger the particle size, which results in poor atomization. In one example, it is defined that the atomizing property is good in the region where the particle size is 50 μm or less, whereas the atomizing property is poor in the region where the particle size is larger than 50 μm.

Further, in FIG. 3B, a general relationship established between the injection pressure of the release agent 20 from the airless spray gun 50 and the particle size of each of the droplets is conceptualized in a graph in the same spray environment. Is represented as. Specifically, the lower the injection pressure, the larger the particle size, which results in poor atomization. Similar to the above, in one example, the atomizing property is good in the region where the particle size is 50 μm or less, whereas the atomizing property is poor in the region where the particle size is larger than 50 μm. Defined.

Then, in the present embodiment, the viscosity of the release agent 20 is set to a value higher than 0.1 Pa · s (20 ° C.) in order to deteriorate the atomization property. However, the higher the viscosity, the more desirable it is, and there is an upper limit. The upper limit is, for example, 16 Pa · s (20 ° C.). The upper limit is necessary because if the viscosity is too high, the release agent 20 may not atomize at all.

Further, in the present embodiment, the injection pressure is set to a height not exceeding ^{80 kg / cm 2 in order to deteriorate the atomization property.}

Further, in the present embodiment, the equivalent diameter of the nozzle (hereinafter, also referred to as “nozzle diameter”) is set to a value of 0.4 mm or more in order to deteriorate the atomization property. This is because the smaller the equivalent diameter, the easier it is for the release agent 20 to atomize, whereas the larger the nozzle diameter, the more the release agent 20 is maintained in a liquid state and less likely to be atomized.

Furthermore, the spraying conditions that deteriorate the atomization property will be extended.

In the spray gun 50, the pressure acting on the release agent 20 (for example, the injection pressure described later) is usually ^{about 80-200 kg / cm 2} , but in the present embodiment, as described later, for example, 30 The pressure is lower than the normal value, such as -40 kg / cm ^2.

The spray gun 50 may adopt either a diaphragm type, a plunger pump type using a plunger, or a piston pump type using a piston as a method for discharging the release agent 20 as a material from the nozzle of the spray gun 50. However, when the release agent 20 has a high viscosity, it is desirable to adopt a plunger pump type or a piston pump type.

Further, since the spray gun 50 has a low injection pressure as described above, a pressure feeding type (release agent 20 is added) as a method of feeding the release agent 20 as a material into the discharge chamber inside the spray gun 50. Rather than pressing and pushing out), a gravity type (using free fall to inject the release agent 20) or a blow-up type (using the air flow to blow up and inject the release agent 20) may be adopted. However, a pumping type may be adopted.

Regardless of which method is adopted, the spray gun 50 is configured to have a main body 90 and a nozzle tip 92 that is detachably attached to the main body 90. The main body 90 is configured to include a grip 94 gripped by the operator and a trigger 96 operated by the operator.

The nozzle tip 92 has a nozzle into which the release agent 20 is sprayed. The cross-sectional shape of the nozzle can be, for example, circular, elliptical, or slit. In the present embodiment, the cross-sectional shape of the nozzle is elliptical, and the equivalent diameter of the nozzle is 0.59 mm (within the range of 0.4-0.8 mm). Here, the "equivalent diameter" means the outer diameter of the circular region when the opening region of the nozzle opening is replaced with a circular region having the same area.

The discharge amount of the release agent 20 from the spray gun 50 (also referred to as the ejection amount, defined as, for example, the weight of the release agent 20 discharged from the nozzle per fixed time) and the spraying pattern depend on the shape of the nozzle.

In the present embodiment, when the target spraying pattern of the release agent 20 from the elliptical nozzle of the spray gun 50 is viewed from the side (the direction perpendicular to the long axis of the cross-sectional shape of the elliptical nozzle), for example, It is an isosceles triangle (fan shape) that widens as it progresses in the injection direction. In that triangle, for example, the height (spray distance) is about 25 cm and the base length (pattern width) is about 15-20 cm. be.

Further, in the present embodiment, when the elliptical nozzle is adopted, when the injection pressure is 60 kg / cm ² , the ejection amount is 1490 mL / min, and the injection pressure is 30-40 kg / cm ² . When the ejection volume is 750-1000 mL / min.

Features of the spray gun 50

The spray gun 50 applies pressure to the release agent 20 itself by forcibly ejecting the release agent 20 from the nozzle without depending on air blowing.

To explain the principle that the release agent 20 is atomized by the airless spray method using the spray gun 50, first, as shown in FIG. 5, the release agent 20 is sprayed from the nozzle as a liquid film at high pressure. The tip of the liquid film collides with the surrounding static air, which gradually reduces the velocity of the tip of the liquid film. On the other hand, since the pressure for ejecting the release agent 20 is constant, the liquid film becomes wavy. As the wavy liquid film travels in the static air, it receives resistance from the static air, and the wavy liquid film splits into a plurality of parts arranged in the traveling direction of the liquid film.

After that, each of the split liquid films extends in a direction intersecting the traveling direction, and is formed into a concavo-convex string so that the concave portion and the convex portion are repeated in the extending direction.

The uneven string-shaped portion is then divided into a plurality of droplets arranged in the extending direction of the concave-convex string portion, whereby the release agent 20 is formed into droplets.

By the way, since the spray gun 50 directly sprays the high-pressure release agent 20, the amount of the release agent 20 scattered is smaller than that of the air spray gun, and the coating efficiency (for example, with respect to the total weight We of the sprayed release agent 20). Of the sprayed release agent 20, the portion coated on the existing coating film 14 (excluding the scattered portion) is defined as the ratio of the amount W).

That is, since the spray gun 50 atomizes and applies the release agent 20 without using air, the amount of the release agent 20 atomized and scattered in the air is small, which causes health hazards to the environment and workers. The amount is small, and the coating efficiency of the release agent 20 (for example, coating efficiency) is high.

Further, since the release agent 20 can be applied while supplying the release agent 20 to the spray gun 50, it is suitable for streamlining the release work.

Since the spray gun 50 can apply the release agent 20 on the existing coating film 14 at a higher pressure than the air spray gun, a thick film of the release agent 20 can be formed on the existing coating film 14.

However, since the spray gun 50 ejects a larger amount of the release agent 20 than the air spray gun, the release agent 20 applied on the existing coating film 14 is likely to drip unless additional measures are taken. ..

Therefore, in the present embodiment, some measures have been added in order to improve the adhesiveness (adhesiveness, adhesiveness, etc.) of the release agent 20 on the existing coating film 14.

(1) Foaming of the release agent 20 by optimizing the injection factor

In comparison with the air spray gun, according to the experiment of the present inventor, the higher the injection pressure of the release agent 20 from the spray gun 50 (for example, the higher the pressure acting on the spray gun 50 from the air compressor 60). It has been found that the spraying speed of the release agent 20 from the spray gun 50 is increased and the cross-sectional diameter (spraying diameter) of the spraying pattern (for example, conical shape) is reduced.

Further, as described above, by optimizing the injection factor, that is, by combining the high viscosity of the release agent 20, the low injection pressure, and the large nozzle diameter, the particle size of each droplet of the release agent 20 can be increased. The diameter is increased, which increases the flight speed of each droplet as it flies in static air.

As described above, in the present embodiment, by optimizing such an injection factor, each droplet is speeded up in combination with the adoption of the airless spray gun 50 instead of the air spray gun.

Due to the high speed of each droplet, the impact energy when each of the above-mentioned droplets collides with the existing coating film 14 increases, and each droplet becomes finer due to the collision, and the total number of droplets increases, and as a result, The surface area of the droplets as a whole, that is, the contact area with static air, increases. As a result, the droplets entrain more static air and foam. As a result, each droplet becomes finer, and as a whole, a larger number of bubbles (air bubbles) are formed in the release agent 20.

On the other hand, in the release agent 20 having the same coating film thickness, the larger the number of air bubbles, the lighter the weight of each air bubble, and the more difficult it is for each air bubble to flow on the existing coating film 14 due to its own weight. As a result, it is estimated that the adhesiveness of the release agent 20 on the existing coating film 14 is improved, and as a result, the coating film thickness of the release agent 20 on the existing coating film 14 is increased. Further, the thicker the coating film thickness of the release agent 20, the more the release agent 20 is applied to the existing coating film 14 (also referred to as the coating amount, for example, the release agent 20 applied per fixed area (or fixed time)). (Defined as weight) increases.

The inventor's experiment, as the injection pressure, it was found that the range or scope of 30-40kg / cm ² of 30-60kg / cm ² is desirable. The numerical value is that the pattern in which the release agent 20 is sprayed from the spray gun 50 is the above-mentioned target spraying pattern, and the release agent 20 is not sufficiently atomized from the spray gun 50 (without being atomized). It is desirable to set it so that it reaches on the film 14.

(2) Additional effect of increasing the viscosity of the release agent 20

Generally, when a high-viscosity release agent is applied, unlike the case where a low-viscosity release agent is used, when the coating film of the release agent requires a thickness, the release agent flows in the coating film. It is prevented from dripping.

Experiments by the present inventor have revealed that the higher the viscosity of the release agent 20, the better the adhesiveness of the release agent 20 on the existing coating film 14.

Further, the experiment of the present inventor has revealed that it is desirable that the paint viscosity of the release agent 20 is as high as about 5 to about 16 Pa · s (20 ° C.).

(3) High degree of emulsification of release agent 20

According to the experiment of the present inventor, as the degree of emulsification of the release agent 20 is higher, the number of bubbles generated in the release agent 20 due to the collision with the existing coating film 14 increases and the bubbles become finer, and as a result, the existing coating film 14 The fact that the adhesiveness of the release agent 20 on the top is improved has been found.

Based on this finding, an emulsion, that is, an aqueous release agent (for example, the first remover in FIG. 2) was adopted as the release agent 20.

However, according to the experiments of the present inventor, even if the release agent 20 is a non-emulsion, that is, a solvent-based release agent (for example, the second to fourth removers in FIG. 2), the coating thickness of the release agent 20 is conventionally determined. It was found that the coating method, that is, the method using an air spray gun or the method using a brush coating, is thicker.

<Component composition of release agent 20>

The release agent 20 contains a main component, an auxiliary agent, and a thickener regardless of the type.

The main component contains an organic solvent in order to swell the existing coating film 14 and easily peel it off from the surface of the structure 12. Examples of the organic solvent include an alcohol-based high boiling point solvent, an ester-based organic solvent, and a complex cyclic organic solvent.

The auxiliary agent exists for stabilizing the properties of the release agent 20, and includes, for example, aromatic hydrocarbon solvents, terpenes and the like.

The thickener is present so that the release agent 20 can be applied on the existing coating film 14 in a predetermined amount to prevent dripping, and examples thereof include silicate compounds and organic bentonite.

<Variation of composition of release agent 20>

As shown in FIG. 2, in the present embodiment, there are four types of release agents 20 that can be applied onto the existing coating film 14 by the spray gun 50, such as the first to fourth removers.

Among them, the first remover is a water-based release agent (emulsion), while the second-fourth remover is a solvent-based release agent (non-emulsion).

Furthermore, the 1st and 2nd removers show normal reactivity in the high temperature period when the average temperature is higher than about 10 ° C, and their use is recommended, whereas the 3rd remover has an average temperature of less than about 10 ° C. Even in the low temperature period, it shows normal reactivity and its use is recommended.

Since the fourth remover contains dichloromethane, safety management measures are required to prevent health damage to workers, but it dries faster than other removers and exhibits strong peeling power. It is recommended that this fourth remover be used for partial repair.

1. 1. Solvent-based release agent

It contains an organic solvent as the main component (20-90%), and also contains an auxiliary agent, a thickener and the like as an auxiliary component.

2. Water-based release agent

It contains an organic solvent as a main component (30-50%), and also contains an auxiliary agent, a thickener and the like and water (35-50%) as auxiliary components.

In general, water-based strippers are less hazardous than solvent-based strippers.

An aqueous release agent is an emulsion in which a main component and water are emulsified using a surfactant.

<Foam type airless coating peeling method>

The foaming type airless coating peeling method according to the present embodiment has the preparation step S100 shown in FIG. 3 and the construction step S200 shown in FIG. 4 in that order.

<Preparation process>

As shown in FIG. 3, first, in step S101, the operator investigates the existing coating film 14 to be peeled off. Specifically, the existing coating film factors such as the material, coating film thickness, and surface texture (for example, surface roughness μmRmax) of the existing coating film 14 and the structure factors such as the structure and shape of the structure 12 are investigated.

Next, in step S102, the operator selects the construction time for peeling off the existing coating film 14. If the construction time is selected, the average temperature of the environment at that construction time is predicted. The average temperature is referred to to determine which of the four types of removers described above is optimal.

Subsequently, in step S103, the operator selects the peeling condition. Specifically, based on the above-mentioned existing coating film factor and / or structure factor for the existing coating film 14, any one of the first to fourth removers in FIG. 2 is selected as the release agent 20 to be used this time. .. At this time, as described above, the release agent 20 used this time is selected so as to have a viscosity suitable for deteriorating the atomization property of the release agent 20 in airless coating.

Further, it is determined how many times the peeling operation using the peeling agent 20 this time is repeated according to the factor including the investigated coating thickness. Further, the target coating film thickness of the release agent 20 in each peeling operation is determined based on the existing coating film factor and / or the structure factor described above.

Specifically, among the existing coating film factors, the release agent 20 is formed by being adhered to the surface of the existing coating film 14 according to the surface roughness (for example, unit: μmRmax) of the existing coating film 14. Determine the target coating film thickness (average coating film thickness, etc.) of the coating film to be applied.

More specifically, according to a predetermined relationship, the target coating film thickness of the release agent 20 is determined according to the surface roughness of the existing coating film 14, so that the smaller the surface roughness, the thicker the target coating film. ..

FIG. 8 conceptually shows an example of the relationship between the surface roughness of the existing coating film 14 and the target coating film thickness of the release agent 20 in a graph. The lower the surface roughness, that is, the higher the surface smoothness, the more the total area in which the release agent 20 contacts the microscopic surface of the existing coating film 14 when the release agent 20 is applied to the surface of the existing coating film 14. (It is the total area of the microscopic surface in consideration of the surface unevenness, hereinafter referred to as "microscopic total contact area") is narrow.

The larger the total microscopic contact area for the projected area of the surface of the existing coating film 14 (that is, the total area of the macroscopic surface ignoring the surface unevenness), the more the release agent 20 can apply the existing coating film 14 at once. While the peeling speed is high, the narrower the total microscopic contact area is, the lower the speed at which the peeling agent 20 peels off the existing coating film 14 at one time, so that the peeling agent 20 takes more time. It is desirable to keep in contact with the existing coating film 14.

Therefore, in order to maximize the peeling speed of the release agent 20, the lower the surface roughness of the existing coating film 14, the thicker the coating film of the release agent 20 is, thereby making each part of the surface of the existing coating film 14 thicker. In addition, it is desirable that the release agent 20 laminated in the film thickness direction keeps contacting one after another from the portion close to the surface.

In addition, it may be assumed that the relationship between the surface roughness of the existing coating film 14 and the target coating film thickness of the release agent 20 is the opposite of that described above.

Specifically, the higher the surface roughness of the existing coating film 14, the larger the total microscopic contact area for the macroscopic total area. Therefore, the coating film of the release agent 20 is thickened to match it. It is also assumed that it is effective to increase the total coating amount by increasing the amount of the release agent 20 in contact with each part of the microscopic surface of the existing coating film 14 among all the parts. Can be done.

Further, the target coating amount is determined from the target coating thickness determined as described above. Further, the target discharge amount of the release agent 20 from the spray gun 50 is determined according to the determined target coating amount, and in some cases, the nozzle tip 92 to be used this time is selected. However, at this time, as described above, the nozzle tip 92 used this time is selected so as to have an equivalent diameter suitable for deteriorating the atomization property of the release agent 20 in airless coating.

Further, the injection pressure when the spray gun 50 pressurizes the release agent 20 this time and injects it from the nozzle is determined according to the viscosity of the release agent 20 this time and the target discharge amount of the release agent 20 from the nozzle. do. However, at this time, as described above, the injection pressure is selected so as to have a height suitable for deteriorating the atomization property of the release agent 20 in the airless coating.

<Construction process>

As shown in FIG. 4, first, in step S201, the operator implements the above-mentioned foam-type airless coating method on the existing coating film 14.

The foaming airless coating method includes a preparatory step in which the worker prepares or procures the release agent 20 and puts it into the tank 30, and the worker activates the pump 40. It has a pumping step of pumping the release agent 20 from the tank 30 to the spray gun 50 in an airless state.

In the foam type airless coating method, the operator further grasps the spray gun 50 and aims at the target, that is, the existing coating film 14, and pulls the trigger 96 in that state, whereby a plurality of release agents 20 are removed from the spray gun 50. It has an injection step of dividing into droplets and injecting them toward a target.

The injection step does not include a step of bringing the release agent 20 into contact with the flow of compressed air and atomizing the release agent 20 by the principle of atomization, and further, the release agent 20 is made before the release agent 20 is injected from the nozzle 92. Does not include the step of foaming.

The foam-type airless coating method further includes a coating step in which the operator applies the sprayed release agent 20 on the surface of the existing coating film 14.

In the coating step, during the coating, the plurality of droplets of the release agent 20 collide with the surface of the existing coating film 14, whereby the plurality of droplets entrain air in the atmosphere and foam. As a result, the release agent 20 is applied onto the surface of the existing coating film 14 in a foamed state.

In one example, the release agent 20 is previously applied so that the coating step has a plurality of bubbles in which the foamed release agent 20 has an average diameter in the range of about 0.1 mm to about 0.5 mm. It is carried out so as to be applied on the surface of the film 14.

In another example, the release agent 20 is such that in the coating step, the average coating film thickness of the coating film formed by the release agent 20 being applied onto the surface of the existing coating film 14 is about 1 mm. Is applied onto the surface of the existing coating film 14.

In yet another example, in the coating step, the average coating film thickness of the coating film formed by the release agent 20 being applied onto the surface of the existing coating film 14 is within the range of about 2 mm to about 5 mm. As shown in the above, the release agent 20 is applied onto the surface of the existing coating film 14.

In any of the examples, the existing coating film 14 is swollen and softened by the release agent 20, and the adhesive force of the structure 12 to the surface is reduced, and as a result, the existing coating film 14 is lifted from the surface of the structure 12.

Next, in step S202, after the application of the release agent 20 is completed, the operator wraps the surface of the existing coating film 14 with a protective sheet having impermeable to the release agent 20, whereby the release agent 20 ( It prevents the vaporized gas generated from (when it is volatile) from being released into the atmosphere from the surface of the existing coating film 14. The protective sheet is, for example, a flexible polyethylene sheet, a polypropylene sheet, or the like.

According to the experiment of the present inventor, as an effect of the wrapping, the release of vapor (vaporization gas) from the release agent 20 applied on the existing coating film 14 is prevented, whereby about 90% of the vapor is released from the existing coating film. It was confirmed that it penetrated into 14 and promoted the efficiency of the peeling work.

Subsequently, in step S203, after the required time (for example, 16-48 hours) has elapsed from the completion of the coating, the operator peels off the protective sheet from the existing coating film 14 and removes it. After that, the operator physically peels off the existing coating film 14 that has been lifted from the surface of the structure 12 due to the adhesive force reduced by the release agent 20 from the structure 12 and removes it.

In order to physically peel off the existing coating film 14 from the structure 12, the operator may use a scraper as a hand tool.

Further, in order to remove the coating film residue which is a part of the existing coating film 14 remaining on the surface of the structure 12 after the first peeling operation, a wire brush as an electric rotary tool (for example, a cup-shaped wire brush) is used. ) Or an air grinder may be used.

Since this removal work imposes a heavy burden on the operator, it is important that the electric rotary tool is as light as possible and that the peeled coating film residue does not scatter. Therefore, it is desirable that the electric rotary tool is small and the rotating portion rotates at a lower speed than usual.

In addition, if desired, the operator may use an additional or alternative high pressure washer to remove the existing coating film 14 and / or coating film residue.

According to the present embodiment, in order to achieve the target coating thickness of the release agent 20, a brush or a roller requires a plurality of coating operations, but the target coating thickness is set to once. This can be achieved by coating work, and work efficiency is improved.

Further, in the present embodiment, the release agent 20 is installed in-line from the installation location (in FIG. 1, the main body portion of the airless coating machine 10 excluding the spray gun 50 is fixedly installed) (work with the main body portion). The spray gun 50, which is a place, can be fed to the work place (in a state of being connected to each other by a continuous pumping line 78).

Specifically, the main body of the airless coating machine 10 (particularly, the pressure pump 40) and the spray gun 50 are connected to each other by a hose (line) 78 that serves as both a pressure transmission path and a material supply path. .. As a result, unlike the case of air coating (spray coating), the main body (particularly, the pressure pump 40) and the spray gun 50 can be connected to each other by both a pressure transmission path and a material supply path that are independent of each other. It becomes unnecessary.

As a result, the release agent 20 can be reliably supplied to the spray gun 50. Specifically, the release agent 20 is unplanned while the release agent 20 is being supplied from the main body to the spray gun 50. It will not leak to the work floor or the like and the part will not be contaminated with the release agent 20.

<Adhesiveness test>

Types of release agent 20 used in the adhesiveness test

The type of the release agent 20 used in the coatability test is the first remover (high viscosity emulsion) shown in FIG. A specific example of the first remover has the following component composition.

Moisture: 40-50% by weight
Alcohol solvent: 40-50% by weight
Petroleum solvent: 1-5% by weight
Surfactant: 1-5% by weight
Thickener: 1-5% by weight
Rust prevention: less than 1% by weight Waxes: less than 1% by weight

Moreover, the specific example has the following properties.

Appearance: Viscous liquid showing white or pale yellow Viscosity: 5-16 Pa · s (20 ° C)

Example

260 g of release agent 20 and a spray gun 50 were airlessly applied to a 500 × 500 mm steel sheet for coating as a test piece, whereby ^{a coating amount of 1.0 kg / m 2} (coating density, spraying density) was applied to the test piece. Was realized.

After the application, the test piece was hung vertically, and the test piece was photographed after 5 minutes in order to observe the dripping condition of the release agent 20. The photograph is attached to the upper part of FIG.

Comparative example

260 g of release agent 20 and a brush (not shown) are applied to a 500 × 500 mm steel sheet for coating as a test piece, whereby ^{a coating amount of 1.0 kg / m 2} (coating density, spraying) is applied to the test piece. Density) has been achieved.

After the application, the test piece was hung vertically, and the test piece was photographed after 5 minutes in order to observe the dripping condition of the release agent 20. The photograph is attached to the bottom of FIG.

Contrast observation

In the examples, dripping of the release agent 20 (for example, unplanned behavior of the release agent 20 due to gravity such as traces of the release agent 20 flowing and dropping of the release agent 20) could not be observed at all. The surface of the release agent 20 applied to the test piece was smooth.

As is clear from the upper photograph of FIG. 6, in the examples, it was confirmed that the release agent 20 applied to the test piece did not flow down from the test piece at all.

Further, the average coating thickness of the release agent 20 adhered to and fixed to the test piece without dripping from the test piece (for example, the coating thickness when applied only once without recoating) is about 2 mm to about. It was also confirmed that it was within the range of up to 5 mm.

Furthermore, it was also confirmed that the release agent 20 in a foamed state on the test piece had a plurality of bubbles having an average diameter in the range of about 0.1 mm to about 0.5 mm.

On the other hand, in the comparative example, dripping (or flow, flow line) of the release agent 20 was observed over the entire test piece. Further, on the surface of the release agent 20 applied to the test piece, a material flow occurred and a streak-like uneven pattern was present.

As is clear from the photograph at the bottom of FIG. 6, in the comparative example, it was confirmed that a part of the release agent 20 applied to the test piece flowed down from the test piece.

In addition, in order to confirm the effect of the present embodiment, the present inventor has described a steel tower as a building having a surface on which the release agent is difficult to spread due to its complicated shape. The peeling work was actually performed using the foaming type (foaming promotion type) airless coating peeling method according to the embodiment. As a result, it was confirmed that the peeling work was ensured, that is, the existing coating film was peeled to every corner, and that the efficiency was improved, that is, the time for the peeling work was shortened.

Further, in the above description of the present embodiment, the phenomenon that the release agent 20 foams is referred to as static air in the process in which the release agent 20 ejected from the spray gun 50 flies in the static air. The plurality of droplets split from the release agent 20 do not become air bubbles due to the collision with the existing coating film 14, and only when the plurality of droplets collide with the existing coating film 14, the plurality of droplets become air bubbles and the release agent 20 foams on the existing coating film 14. It was described as an aspect of doing so.

However, in the process in which a plurality of droplets of the release agent 20 fly in static air, the present invention may be carried out in such a manner that at least a part of the droplets becomes air bubbles due to collision with static air. Do not exclude.

As described above, some of the exemplary embodiments of the present invention have been described in detail with reference to the drawings, but these are examples, and those skilled in the art, including the embodiments described in the [Summary of Invention] column. It is possible to carry out the present invention in other forms with various modifications and improvements based on knowledge.

Claims (7)

It is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle, whereby the release agent is divided into a plurality of droplets and collides with the surface of the coating film. Injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. A coating film peeling method comprising a method in which each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles. The coating film peeling method according to claim 1, wherein the spraying step sprays the release agent from the nozzle so that the average particle size of the plurality of droplets when colliding with the surface of the coating film is larger than 50 μm. The coating film peeling method according to claim 1 or 2, wherein the equivalent diameter of the nozzle is set to a value of 0.4 mm or more. The injection process according to claim 1 wherein said release agent pressurized by the viscosity and injection pressure with a height that varies in accordance with the discharge amount and from the nozzle of the release agent in the release agent that be injected from the nozzle The coating film peeling method according to any one of 3 to 3. The release agent is volatile and has
The coating film peeling method further
After the application of the release agent is completed, the coating film surface is wrapped with a protective sheet that is impermeable to the release agent, whereby the vaporized gas generated from the release agent is released from the coating film surface to the atmosphere. The wrapping process to prevent it from being done,
After a lapse of a predetermined time, a peeling step of peeling the protective sheet from the existing coating film and further peeling the existing coating film softened by the release agent from the structure.
Coating peeling method according to any one of claims 1 to 4 comprising. It is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
An injection step of injecting the release agent using an airless spray gun to divide it into a plurality of droplets.
The smaller the surface roughness of the existing coating film, the smaller the surface roughness of the coating film to be formed by applying the sprayed release agent onto the surface of the coating film and the coating agent on the surface of the coating film. With the coating process of applying so as to have a large coating film thickness
Coating film peeling method including. In the coating step, the release agent is made to collide with the coating film surface as the plurality of droplets, whereby the plurality of droplets are entrained with air in the atmosphere and foamed, whereby the plurality of droplets are formed. The coating film peeling method according to claim 6 , wherein the droplets are adhered and fixed on the coating film surface as a plurality of air bubbles.

Images