JP7021140B2 - Paint peeling method and paint peeling device - Google Patents

Description

The present invention is a rust preventive layer or coating applied to the surface of steel structures, steel materials, steel parts, etc. (hereinafter referred to as "steel materials") in various fields such as bridges, elevated roads, power transmission towers, radio towers, and steel-framed buildings. The present invention relates to a method for peeling films and a peeling device used for peeling them.

The surface of the steel material is painted. Normally, for painting, a rust preventive is applied to the surface of the steel material, and an outer coating layer (coating film) is applied on top of the rust preventive. The coating systems used for steel materials include A-based coatings and B-based coatings that use lead-tan or lead-based rust-preventing paints for rust prevention, and C-based coatings that use inorganic zinc rich paint (hereinafter referred to as "inorganic zinc") for rust prevention. There is. Names such as A-based coating, B-based coating, and C-based coating are described in the standard called "Steel Road Bridge Anticorrosion Handbook" by the Japan Road Association.

In A-based coating and B-based coating, as shown in FIG. 4A, an etching primer is applied to the surface of the blasted steel material X, and lead tan or lead-based rust preventive paint (hereinafter referred to as lead rust preventive paint) is applied to the outside (top) of the etching primer. A "lead tan paint") is applied to form the rust preventive layer 1. A resin paint such as a phthalic acid resin paint is applied to the outside of the lead tan paint to form an outer coating layer (coating film) 2.

In C-based coating, as shown in FIG. 4 (b), an inorganic zinc for rust prevention is applied to the surface of the blasted steel material X, and a mist-like mist coat is sprayed from the outside (top) of the blasted steel material X to provide air in the inorganic zinc. The holes are filled to form the rust preventive layer 1. An outer coating layer 2 made of an epoxy resin, a fluororesin, a polyurethane resin, or the like is formed on the outside of the mist coat.

The coating of steel materials needs to be repainted regularly because it is corroded and deteriorated due to various factors such as wind and rain and ultraviolet rays. In this case, when a lead-containing paint is used as the rust preventive material such as A-based paint and B-based paint, it is preferable to remove all the paint on the surface of the steel material in terms of rust prevention. In the case of C-based coating, since the inorganic zinc in the rust preventive layer exerts a sacrificial anticorrosion effect, it is considered desirable to repaint while leaving the rust preventive layer as long as it is sound.

Conventionally, as a method of peeling off the paint on the surface of a steel material, a method of scraping off the paint with a grinder, a sander, or a cup brush, a method of scraping off the paint with sandblast (mechanical method: Patent Document 1), or a chemical method of applying a release agent. A construction method (chemical construction method: Patent Document 2) and a construction method in which coating is peeled off by electromagnetic induction heating (IH construction method: Patent Documents 3 to 5) have been proposed. In the IH method of Patent Document 5, the coating film softened by heating is peeled off in the form of a sheet or a mass that does not become dust by a tool, and the rust preventive paint remaining on the steel surface of the peeling mark is scraped by scraping with a scraper. Dropped (peeled).

When the paint is peeled off by the mechanical method or the scraper, the paint powder is scattered on the work site. Not only the rust preventive paint (lead tan paint) contains lead components and heavy metals, but also the paint of the outer coating layer may contain PCB (polychlorinated biphenyl). Since lead components and PCBs are harmful components to the human body, when the worker inhales the powder scattered on the work site and the harmful substances are ingested from the respiratory and digestive organs, some of them are mixed in the blood. accumulate. In particular, in the case of lead components, there is a risk of lead poisoning or health problems if the accumulated amount increases. In order to prevent the suction of lead components, the current situation is that workers always wear a full-face mask with a filter on their face.

(Health disorders caused by inhalation of lead components)
Aging infrastructure facilities such as highways and river bridges built during the period of high economic growth, the generation of lead components during rebuilding and repairs, and health problems caused by suction of lead components are major social solutions. be.

(Problems with lead and health problems)
The Civil Engineering Data 55-2 (2013) contains a report entitled "Removal of Lead-Containing Paints When Repainting Steel Road Bridges", which addresses the issues of lead and health problems.

(Documents on lead and health problems in the Safety and Health Department, Labor Standards Bureau, Ministry of Health, Labor and Welfare)
On May 30, 2014, a document entitled "Preventing Workers' Health Disorders in Peeling and Scraping of Paints Containing Hazardous Substances such as Lead" was published by the Health and Safety Department, Occupational Health Division, Labor Standards Bureau, Ministry of Health, Labor and Welfare. It is sent to the Chief of Health Affairs Section, Labor Standards Department, Prefectural Labor Bureau under the name of the Chief of Chemical Substance Countermeasures Section. According to this document
"(About those who order work such as paint peeling)
1 Those who place an order for work such as peeling off paint applied to construction such as bridges should inform the enforcer of information that they are aware of the presence or absence of harmful chemical substances such as lead and chromium in the applied paint. , Consider the necessary expenses for investigation of harmful substances in paint and measures to prevent exposure. ".
again,
"4 Work such as peeling off paint containing harmful substances such as lead is referred to as a work site that has been isolated in consideration of the surrounding environment or a work site that is closed in a narrow space such as indoors (hereinafter referred to as" work site in an isolated area, etc. " When working in.), The concentration of dust of harmful substances such as lead in the area will be extremely high, so the following measures should be taken.
(1) Peeling, etc. Workers must be wet. If moistening is extremely difficult, take measures to reduce the dust concentration to the same level as when moistening in the work environment before carrying out the work. ".

(Disaster investigation report of National Institute of Occupational Safety and Health)
In December 2014, the National Institute of Occupational Safety and Health issued the "Disaster Investigation Report" A-2014-04 (open to the public). Regarding the case that was investigated by ..., it was estimated.
Generally, paints containing harmful substances such as lead are expected for the purpose of preventing rust, but the concentration of dust such as lead is extremely high when peeling paints in a closed space, especially when dry. Since the concentration will be high, it is necessary to make a drastic review of the construction method, such as always performing the work in a wet manner and sufficiently collecting and exhausting dust in the work area. ".

(Basic knowledge of work environment measurement)
In the "Working environment measurement" of "Basic knowledge of working environment measurement" published by the Japan Working Environment Measurement Association, "If there is a harmful factor in the working environment, do you remove the harmful factor? If the reduction to a certain limit, or if these measures alone cannot reduce the worker's exposure to harmful factors to a sufficient degree, personal protective equipment, protective clothing, etc. It is necessary to prevent health problems caused by the harmful factors by using measures to prevent exposure. "
Furthermore, according to the "measurement target substance and control temperature (working environment evaluation standard attached table)" of this basic knowledge, the control concentration when the substance is "lead and its compounds" is "0.05 mg / m ³ as lead". Are listed.

As described above, the harmfulness of components harmful to the human body, especially lead components (health disorders), has become a problem and is an urgent issue to be solved.

(Peeling of coating film by IH method)
The inventor of the present invention has previously developed a "painting and repainting method for steel members" (IH method) by high-frequency induction heating, and obtained a patent (Patent Document 5). In the IH method, an IH heater is applied on the coating film to heat the coating film, soften it, float it from the undercoat layer (rust preventive layer), and push a peeling tool such as a stephanolepis crab or scraper under the coating film to apply the coating film. It is a method of peeling off. At this time, since the coating film is peeled off in the form of a sheet or as a lump that does not easily become dust, the dust of the coating film and the dust of the undercoat layer that adheres to the coating film and is peeled off from the surface of the steel material are also difficult to scatter. However, since the rust preventive layer remaining on the surface of the steel material is peeled off after the coating film is peeled off, the peeling tool is pressed against the remaining rust preventive layer and rubbed, so that it is unavoidable to generate dust in the rust preventive layer. Since the rust preventive layer contains lead components, lead tan paint, and other harmful substances (hereinafter referred to as "hazardous substances"), workers wear a full-face mask with a filter during the work. However, it is not possible to completely prevent the suction of dust containing harmful substances.

In order to suppress the generation of dust containing harmful substances, conventionally, while rubbing the surface of the steel material with a scraper held in one hand to peel off the coating film, the suction device (vacuum) is operated with the other hand, and it is generated at the time of peeling. Dust is sucked with a vacuum nozzle. However, in general, since the work space is not sucked under a negative pressure, the suction effect by the vacuum is only near the tip of the nozzle, and the generated dust cannot be sufficiently sucked. Moreover, in order to suck the dust, it is necessary to always bring the tip of the scraper close to the suction nozzle, which is quite difficult. The vacuum used is a vacuum with a filter used in clean rooms of electronic parts and hospitals, and the exhaust does not contain dust components, so the exhaust is on the floor so as not to fly up dust. It is designed not to hit.

As a measure against dust, in addition to the method of sucking dust with a vacuum as described above, there is also a method of humidifying. As an example of the method by humidification, there is an example of sprinkling water at a building demolition site or a construction site. In this case, the sprinkled water collects on the scaffolding and it becomes difficult to work, or the work site becomes excessively humid and the work environment deteriorates.

Japanese Unexamined Patent Publication No. 2011-0563333 Japanese Patent No. 3985966 U.S. Pat. No. 7857914 Japanese Unexamined Patent Publication No. 2014-014933 Japanese Unexamined Patent Publication No. 2017-124391

An object of the present invention is to suppress or prevent the generation and scattering of dust when the coating film on the surface of a steel material is peeled off or when the rust preventive layer is peeled off (hereinafter, both are collectively referred to as "prevention").

The paint peeling method of the present invention is a paint that peels off a coating film coated on the surface of a steel material and a rust preventive layer containing lead tan or lead (hereinafter referred to as "hazardous substance-containing paint") under the coating film . It is a peeling method, in which the steel material is heated by lead heating to soften the coating film on the surface of the steel material so that it emerges from the toxic substance-containing paint, and the coating film that softens and rises from the toxic substance-containing paint is in the form of a sheet or in a mass. While turning up from the surface of the toxic substance-containing paint, the coating film is sprayed (sprayed) with high-temperature steam (hereinafter referred to as "steam") between the sheet-like or lumpy coating film and the toxic substance-containing paint. The toxic substance-containing paint adhering to the back surface of the steel material and the toxic substance-containing paint remaining on the surface of the steel material after the coating film is turned up are moistened , and the sheet-like or lumpy state is caused by the heat of the sprayed steam. This is a method of re-softening the coating film and peeling off the wet toxic substance-containing paint remaining on the surface of the steel material with a peeling tool to prevent the generation of dust of the toxic substance-containing paint at the time of peeling.

The paint peeling method of the present invention can also inject steam between the coating film turned up from the harmful substance-containing paint and the peeling tool .

The paint peeling device of the present invention is a device that peels lead tan or a harmful substance-containing paint containing lead under a coating film that is peeled from the surface of a steel material in the form of a sheet or in a mass, and is a steam injector. The steam injector is provided with a release tool , a one-handed handle, an injection portion provided at the tip of the one-handed handle, a nozzle provided at the tip of the injection section, and the one-handed handle. A switch is provided, the release tool is provided with a handle fixed to the injection portion and a rubbing portion provided on the tip of the handle, and the steam injector and the release tool are closer to the coating film when the coating film is peeled off. The release tool is provided under the steam injector so that the release tool is located and the steam injector is located at a position farther from the coating film than the release tool, and the release tool is the tip of the rubbing portion. Is provided in the injection portion so as to project toward the tip of the nozzle . The release tool can also be detachably provided on the injection portion.

The paint peeling method of the present invention has the following effects.
(1) Since the toxic substance-containing paint is scraped off after moistening with steam, it is possible to prevent the generation of dust in the toxic substance-containing paint and prevent the health hazard of the worker due to the toxic substance-containing paint.
(2) When water is sprinkled on paint containing harmful substances, the work platform becomes flooded and it becomes difficult to work, the work site becomes excessively watery, the work environment deteriorates, and the accumulated water is discharged to the outside. However, in the present invention, steam is injected, so that there is no such problem.
(3) Since it is possible to prevent the generation of dust in the paint containing harmful substances, it is not necessary to surround the work site with a cover for preventing dust diffusion. Therefore, the work site is not restricted by the cover and becomes narrow, which makes it difficult to perform the peeling work.
(4) Since it is possible to prevent the generation of dust in the paint containing harmful substances, it is not necessary to enclose the work site with a cover for preventing dust diffusion and apply negative pressure. Therefore, it is not necessary to introduce a device that applies negative pressure.
(5) Since steam is applied to the peeled portion, the temperature rises and the coating film softens, making it easier to peel.

The paint peeling device of the present invention has the following effects.
(1) Since steam can be injected from the steam injector to scrape off the toxic substance-containing paint while moistening it, it is possible to prevent the generation of dust in the toxic substance-containing paint.
(2) Regardless of whether the steam injector is integrated with or separated from the release tool, it is possible to scrape off the harmful substance-containing paint with the release tool while injecting steam from the steam injector. It is possible to prevent the generation of dust in the contained paint.

Explanatory drawing of an example of the paint peeling method of this invention. (A) is an explanatory view of a steam injector in the paint peeling device of the present invention, and (b) is an explanatory view of a peeling tool. Explanatory drawing of the induction heating apparatus used in this invention. (A) is a schematic explanatory view of A-based coating using lead tan as a rust-preventive material, and (b) is an schematic explanatory view of C-based coating using inorganic zinc as a rust-preventive material.

(Embodiment of paint peeling method)
An embodiment of the paint peeling method of the present invention will be described with reference to the drawings. The paint peeling method of the present invention comprises an outer coating layer (coating film) 2 applied to the surface of a steel material X (FIGS. 4A and 4B) such as an elevated road, a bridge, and a steel frame of a building, and a rust preventive layer under the outer coating layer (coating film) 2. It is a method of peeling off (hazardous substance-containing paint) 1, and can be applied as follows.

After the coating film 2 on the surface of the steel material X is heated by a heating device to be softened, the coating film 2 is peeled off in the form of a sheet or in a mass, and the coating film 2 is peeled off during or after the coating film is peeled off. Steam is sprayed onto the toxic substance-containing paint 1 below to humidify the toxic substance-containing paint 1, moisten it, and then peel it off.

The heating device is not particularly limited as long as it can heat and soften the coating film 2 and can be lifted from the steel material X or the surface of the toxic substance-containing paint 1, but it is not particularly limited, but an induction heating device (IH (induction)). heating) heating device) is suitable. The IH heating device will be described later.

[Steam type]
The steam to be sprayed is not particularly limited as long as it can wet the toxic substance-containing paint 1, but it may be either saturated steam, superheated steam, or the like.

[Steam injection point]
When the steam is injected, it evaporates in a short time, for example, instantly or in a few seconds after the injection. Therefore, it is desirable that the injection location is a location where the toxic substance-containing paint 1 can be efficiently wetted. Whether sprayed during or after the paint film is peeled off, it is directed directly toward at least the toxic substance-containing paint 1 or its surroundings, or both the toxic substance-containing paint 1 and its surroundings. It is desirable to spray on. The tip of the stripper 3 (FIG. 1) such as a scraper or its surroundings is desirable. If the vapor is sprayed during the peeling of the coating film after heating, steam is sprayed into the space 4 (FIG. 1) between the back surface of the peeled coating film 2 and the toxic substance-containing paint 1 as shown in FIG. It is desirable to simultaneously spray both the toxic substance-containing paint 1 adhering to the back surface of the coating film 2 and the toxic substance-containing paint 1 remaining on the surface of the steel material X. In this case, both the coating film 2 and the toxic substance-containing paint 1 can be peeled off at the same time while injecting steam.

By injecting steam into the space 4 between the coating film 2 and the steel sheet X during peeling, the steam that has come into contact with the cold steel material X and the coating film 2 efficiently condenses (liquefies) and contains harmful substances on the surface of the steel material. When the paint film 1 is scraped off by the release tool 3, it surely becomes wet. By scraping off the toxic substance-containing paint 1 while moistening it, it is possible to prevent the generation and scattering of dust of the toxic substance-containing paint 1.

After peeling off the coating film, the harmful substance-containing paint 1 remaining on the surface of the steel material X is peeled off by the peeling tool 3, and then the tip surface (scraped surface) of the peeling tool 3 or the harmful substance-containing paint 1 around it is peeled off. Steam is sprayed toward the paint to moisten and peel off the toxic substance-containing paint 1.

Unlike watering, steam injection is an amount that volatilizes immediately even at room temperature, so water accumulates at the work site like when watering, making the scaffolding worse and making it difficult to work. There is no need to drain the accumulated water.

[Steam injection amount, injection pressure]
Both the steam injection amount (discharge amount) and the steam injection pressure are set to an amount that can wet the toxic substance-containing paint 1, and a pressure that is easy to wet.

[Peeling of coating film]
The coating film 2 on the surface of the steel material X is softened by heating with a heating device, and is easily lifted from the steel material X or the toxic substance-containing paint 1 and easily peeled off. In addition, the heat of the injected steam also softens and easily peels off. However, since the coating film 2 becomes hard and difficult to peel off when the temperature drops, it is desirable to peel off the coating film 2 before the coating film temperature drops while heating.

[Peeling of paint containing harmful substances]
The toxic substance-containing paint 1 moistened with steam is softened by the heat of the steam, but when the steam evaporates and the temperature drops, it becomes hard and difficult to peel off. Is desirable.

A peeling tool 3 is used for peeling the coating film 2 and the harmful substance-containing paint 1. The peeling tool 3 is a tool such as a scraper or a kawaski. The toxic substance-containing paint 1 is scraped off (peeled) by manually rubbing or automatically rubbing those tools.

(Embodiment of Paint Remover)
An example of the paint peeling apparatus of the present invention will be described below. This paint peeling device includes a peeling tool 3 that rubs and peels the coating film 2 and the toxic substance-containing paint 1, and a steam injector 5 that injects steam directly to or around the toxic substance-containing paint 1 (FIG. 2A). ). The release tool 3 and the nozzle 6 of the steam injector 5 may be an integrated type or a separate type.

(Embodiment of Integrated Paint Remover)
As shown in FIG. 1, the integrated paint peeling device is a device in which a peeling tool 3 is fixed to a nozzle 6 of a steam injector 5. It is desirable that the steam injector 5 is provided with an ON-OFF switch 7 for starting / stopping steam injection, an injection amount adjusting unit capable of adjusting the steam injection amount, an injection intensity adjusting unit capable of adjusting the injection intensity, and the like. An existing commercial steam cleaner (steam injector) can be used for the steam injector 5. For example, a commercial steam cleaner sold by Karcher Japan Co., Ltd. is suitable. This commercial steam cleaner is a model that can be used continuously for a long time, unlike household steam cleaners. You need to supply water, but you don't have to wait for the boiler to cool down for water supply.

Various devices can be used for the release tool 3. As an example, an existing metal plate-shaped scraper (FIG. 2 (b)) can be used. The scraper is suitable for an integrated type (FIG. 1) attached to the tip of the nozzle 6 of the steam injector 5 so as to protrude from the tip. In FIG. 1, the scraper is used as a peeling tool 3, and it is attached under the injection portion 9 with a string or other binding tool 8. The attachment may be something other than a string, or may be an adhesive. The release tool 3 can be mounted on the injection portion 9 or in the nozzle 6. The nozzle 6 may be detachable from the injection unit 9. In either case, it is desirable that the release tool 3 is fixed so as not to wobble even if it is rubbed when the coating film 2 is peeled off or the harmful substance-containing paint 1 is peeled off.

(Embodiment of Separable Paint Remover)
The peeling device may be a separate type in which the steam injector 5 and the peeling tool 3 are separated. In this case as well, an existing commercial steam cleaner (steam injector) can be used for the steam injector 5, and an existing metal plate-shaped scraper or other tool can be used for the release tool 3. The steam injector 5 and the release tool 3 may be removable. In this case, the steam injector 5 and the release tool 3 are provided with detachable portions that can be attached to and detached from each other. The coating film 2 can be peeled off or the harmful substance-containing paint 1 can be scraped off with the peeling tool 3 while spraying. When not in use, the steam injector 5 and the release tool 3 can be separated and stored in a storage box or carried.

(Example of using the integrated paint peeling device)
As shown in FIG. 1, the integrated paint peeling device inserts the tip (rubbing surface) of the peeling tool 3 into the back side of the coating film 2 while holding the handle of the steam injector 5 in one hand and injecting steam. Is peeled off into a sheet. At this time, steam is sprayed into the space 4 between the peeled coating film 2 and the harmful substance-containing paint 1 remaining on the surface of the steel material X, and the harmful substances adhering to the back surface of the peeled coating film 2 are sprayed. Both the contained paint 1 and the harmful substance-containing paint 1 remaining on the surface of the steel material X are moistened. In this case, it is desirable that the steam is injected from the nozzle 6 of the steam injector 5 toward the dust generation location. The dust generation location is usually the toxic substance-containing paint 1 near or beyond the tip of the release tool 3. Since the steam easily evaporates, the injected steam hits the tip of the steel plate-shaped scraper and is cooled and evaporated, but the toxic substance-containing paint 1 can be humidified (wet) before evaporating. In this humidified state, the release tool 3 is pressed against the harmful substance-containing paint 1 remaining on the surface of the steel material X, the harmful substance-containing paint 1 is rubbed, and the harmful substance-containing paint 1 is scraped off from the steel material surface. By scraping off in this way, the toxic substance-containing paint 1 can be peeled off while it is soft, and it becomes easy to peel off. In addition, the dust of the toxic substance-containing paint 1 is less likely to scatter. Since the operator can peel off the coating film 2 and scrape off the toxic substance-containing paint 1 with the peeling tool 3 while pressing the switch 7 of the steam injector 5, the worker is distracted by the humidifying work. You can concentrate on the peeling work without having to.

Even if the coating film 2 is heated and softened at the time of peeling, the coating film 2 returns to its original hardness when it cools. However, by injecting high-temperature steam, the coating film 2 is softened again, so that it is easily peeled off by the scraper. Therefore, it is not necessary to rub the surface of the toxic substance-containing paint 1 many times in an attempt to forcibly peel it off, and it is possible to prevent dust generation and scattering of the toxic substance-containing paint 1. Since the toxic substance-containing paint 1 can be humidified while rubbing, the generation and scattering of dust of the toxic substance-containing paint 1 can be prevented.

(Example of using a separate paint peeling device)
In the separable paint peeling device, the handle of the steam injector 5 is held in one hand to inject steam toward the toxic substance-containing paint 1, while the peeling tool 3 is held in the other hand to coat the peeling tool 3. It is inserted into the back surface of 2 and the coating film 2 is peeled off. While peeling, the tip (rubbing surface) of the peeling tool 3 is pressed against the harmful substance-containing paint 1, and the harmful substance-containing paint 1 is rubbed with the peeling tool 3 to scrape off the harmful substance-containing paint 1 from the surface of the steel material X. In this case as well, the steam is sprayed on or around the tip of the release tool 3. The paint is softened by heating with steam and easily peeled off, and the wet lead-tan paint is heated and easily scraped off.

[Heating device]
An IH heating device, a heater, and various other heating devices can be used as the heating device used in the present invention. As an example, the IH heating device 10 (FIG. 3), which the applicant has previously applied for a patent, is used. Suitable. The IH heating device 10 includes a heating head 11, a current transformer CT, a high frequency power supply 12, a handle 13, a protective hose 14, a cable 15, an amplifier 16, a refrigerant circulation device (not shown), and the like. When the heating head 11 is placed on the coating on the surface of the steel material X, the surface of the steel material is heated by induction heating, and the coating film 2 on the surface of the steel material is softened so as to float from the surface of the steel material.

The heating temperature of the surface of the steel material to be coated is preferably 100 ° C. or higher and lower than 250 ° C., particularly about 150 ° C. to 200 ° C. If the heating temperature exceeds 250 ° C, harmful components may be generated from the coating due to overheating, and if it is less than 100 ° C, the separation of the coating may be incomplete due to insufficient heating. However, these numerical values are examples, and the optimum conditions may be selected according to various conditions such as the type of coating, atmospheric temperature, humidity, and weather. As the IH heating device 10, an existing one can be used.

[Experiment using IH heating device]
Using the above-mentioned IH heating device 10, the heating head 11 is placed on the coating film 2 on the surface of the steel material, the surface of the steel material is heated by induction heating, and the coating film 2 is softened and lifted from the surface of the steel material. The tip (rubbing surface) of the peeling tool 3 of the integrated paint peeling device of the above-described embodiment was inserted into the back side of the coating film 2 to peel the coating film 2 into a sheet shape. The total amount of dust generated at this time was 0.63 mg / m ³ , and the amount of lead contained in the dust was 0.17 mg / m ³ .

[Suction experiment with suction tool]
Using the above-mentioned IH heating device 10, the heating head 11 is placed on the coating film 2 on the surface of the steel material, the surface of the steel material is heated by induction heating, and the coating film 2 is softened and lifted from the surface of the steel material. The tip (rubbing surface) of the peeling tool 3 of the integrated paint peeling device of the above-described embodiment was inserted into the back side of the coating film 2 to peel the coating film 2 into a sheet shape. Further, the toxic substance-containing paint 1 remaining on the surface of the steel material X was scraped off by rubbing with the tip of the release tool 3. The dust generated at this time was sucked by an existing vacuum cleaner. The total amount of dust generated at this time was 0.75 mg / m ³ , and the amount of lead contained in the dust was 0.070 mg / m ³ .

[Dust generation experiment by steam injection]
Using the above-mentioned IH heating device, the heating head 11 is placed on the coating film 2 on the surface of the steel material, the surface of the steel material is heated by induction heating, the coating film 2 is softened and lifted from the surface of the steel material. The tip (rubbing surface) of the peeling tool 3 of the integrated paint peeling device of the above-described embodiment was inserted into the back side of the coating film 2 to peel the coating film 2 into a sheet shape. At this time, steam is injected from the nozzle 6 of the steam injector 5 of the integrated peeling device into the space 4 between the peeled coating film 2 and the toxic substance-containing paint 1 remaining on the surface of the steel material X. Both the toxic substance-containing paint 1 adhering to the back surface of the peeled coating film 2 and the toxic substance-containing paint 1 remaining on the surface of the steel material X are moistened, and the harmful substances remaining on the surface of the steel material X in this humidified state. The release tool 3 was pressed against the substance-containing paint 1 and the toxic substance-containing paint 1 was rubbed to scrape off the toxic substance-containing paint 1 from the surface of the steel material. The total amount of dust generated at this time was 0.51 mg / m ³ , and the amount of lead contained in the dust was 0.032 mg / m ³ . In any of the above experiments, m ³ indicates a volume at 25 ° C. and 101.3 kPa. In this experiment, when the coating film 2 and the toxic substance-containing paint 1 are peeled off by the paint peeling method of the present invention using the integrated paint peeling device of the present invention, the total amount of dust generated is also the amount of the toxic substance-containing paint contained therein. The amount was also less than the peeling by the conventional method. This value is the "lead and its compounds" described in "Measurement Target Substances and Control Temperatures (Working Environment Evaluation Criteria Appendix)" in "Basic Knowledge of Working Environment Measurement" published by the Japan Working Environment Measurement Association. It was confirmed that the control concentration was much lower than the control concentration of "0.05 mg / m ³ as lead".

Both the paint peeling method and the paint peeling device of the present invention can be applied to repainting of various steel materials, and heavy anticorrosion coating such as steel girders of steel bridges, marine structures, tanks, water gates, plants, and various steel towers is adopted. Especially suitable for repainting various steel members.

1 Anti-rust layer (paint containing harmful substances)
2 Outer coating layer (coating film)
3 Peeling tool 4 Space 5 Steam injector 6 Nozzle 7 Switch 8 Bundling tool 9 Injection part 10 IH heating device (induction heating device)
11 Heating head 12 High frequency power supply 13 Handle 14 Protective hose 15 Cable 16 Amplifier CT Current transformer X Steel material

Claims (4)

It is a paint peeling method that peels lead tan or lead-containing toxic substance-containing paint under the paint film on the steel surface.
The steel material is heated by induction heating to soften the coating film on the surface of the steel material so that it emerges from the toxic substance-containing paint.
While turning up the coating film that has softened and lifted up from the toxic substance-containing paint from the surface of the toxic substance-containing paint in the form of a sheet or lump, between the coating film in the form of the sheet or lump and the toxic substance-containing paint . By injecting steam into , the toxic substance-containing paint adhering to the back surface of the coating film and the toxic substance-containing paint remaining on the surface of the steel material after the coating film was turned up were moistened and sprayed. The heat of the steam resoftens the coating film in the form of a sheet or a mass ,
The wet toxic substance-containing paint remaining on the surface of the steel material is rubbed with a peeling tool to peel it off.
A paint peeling method characterized by this. In the paint peeling method according to claim 1,
Spray steam between the paint film turned up from the toxic substance-containing paint and the release tool.
A paint peeling method characterized by this. A paint peeling device that peels lead-tan or lead-containing toxic substance-containing paint under a coating film that is peeled from the surface of steel in the form of a sheet or in a mass .
Equipped with a steam injector and a stripper,
The steam injector includes a one-handed handle, an injection portion provided at the tip of the one-handed handle, a nozzle provided at the tip of the injection section, and a switch provided at the one-handed handle.
The release tool includes a handle fixed to the injection portion and a rubbing portion provided on the tip of the handle.
The steam injector and the release tool are such that the release tool is located closer to the coating film when the coating film is peeled off, and the steam injector is located at a position farther from the coating film than the release tool. The release tool is provided under the machine,
The peeling tool is provided on the injection portion so that the tip of the rubbing portion projects toward the tip of the nozzle.
It is a paint peeling device that features. In the paint peeling apparatus according to claim 3,
The release tool is provided on the injection part so that it can be attached and detached.
It is a paint peeling device that features.

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