JP7488609B1 - Method and device for removing asbestos-containing exterior wall paint - Google Patents

Abstract

[Problem] To provide a method for removing asbestos-containing exterior wall coatings, which prevents the exterior wall coating from scattering as dust into the atmosphere during the work of removing the exterior wall coatings of buildings, which is a pre-process of building demolition work, and which can completely remove all of the exterior wall coating from the building body. [Solution] For asbestos-containing exterior wall coating 1 formed on the surface Ca of the concrete C of the building body, the elastic properties of this exterior wall coating 1 are utilized, and the peeling tool 2 is subjected to continuous striking motions while the cutting edge 3 of the peeling tool 2 is abutted against the exterior wall coating 1 at a predetermined inclination angle, thereby continuously peeling the exterior wall coating 1 from the surface Ca of the concrete C. This makes it possible to completely remove all of the exterior wall coating 1 from the building body while preventing the exterior wall coating 1 from scattering as dust into the atmosphere. [Selected Figure] Figure 1

Description

The present invention relates to a method and device for removing asbestos-containing exterior wall paint, and more specifically, to a paint removal technology for removing asbestos-containing exterior wall paint applied as a finishing coating to the exterior walls of buildings during demolition work on old buildings, etc.

During demolition work on old, dilapidated buildings, etc., strict regulations are stipulated under the Air Pollution Control Act to prevent the dispersion of asbestos dust, which is harmful to the human body, and asbestos-containing exterior wall paints applied as finishing coatings to the exterior walls of buildings are also subject to these regulations.

In order to comply with this regulation, when demolishing a building, demolition companies do not immediately demolish the building, but instead remove the exterior paint from the building as a preliminary step. This prevents asbestos contained in the exterior paint from scattering during the demolition work, and also takes measures to ensure that no asbestos remains in the concrete blocks after the building is demolished.

The most common method for removing conventional exterior wall paint is to use a paint stripper.

In this method, before removing the exterior wall paint, a stripping agent is first applied to the entire exterior wall paint. This stripping agent then penetrates the exterior wall paint, moistening and softening it, causing it to swell and float outward from the exterior concrete surface of the building body, making it easier to peel off from the exterior concrete surface. The exterior wall paint that has floated off from the exterior concrete surface is then manually scraped off with a stripping tool such as a scraper or spatula to remove it. This work is carried out over the entire surface of the building that has been treated with the asbestos-containing exterior wall paint.

With this removal method, the exterior wall paint containing asbestos is moistened and softened by the action of the stripping agent, so when it is removed, the exterior wall paint does not turn into dust and fly up into the atmosphere, but can be peeled off and removed from the building itself.

However, in the conventional methods for removing exterior wall paint as described above, the moistened and softened exterior wall paint becomes easier to peel and remove from the building body, but the action of the stripping agent creates new problems, such as the following:

In other words, the exterior concrete surface of the building itself is not flat and smooth, but rather rough and uneven. This is because when a building is newly constructed, a rough, uncoated plywood is used to ensure that the exterior concrete and the exterior paint adhere closely together, intentionally creating an uneven, rough surface for the exterior concrete.

Because of this, the exterior wall paint, which has become moist and softened by the action of the stripping agent, is mostly removed from the exterior wall concrete surface by the stripping work using a stripping tool, but on the other hand, the part of the exterior wall paint that is in contact with the exterior wall concrete surface is also moist and soft, so it is pressed against the exterior wall concrete surface by the pressure of the stripping work using the stripping tool. As a result, part of the exterior wall paint penetrates and clogs small depressions in the rough exterior wall concrete surface, and as a result, the asbestos contained in this exterior wall paint also remains on the building surface.

If the asbestos remaining on the surface of buildings is not completely removed, it will turn into dust and spread into the atmosphere during demolition work, not only posing a health hazard to construction workers and surrounding residents, but will also remain in the concrete blocks after demolition. Such concrete blocks will be processed into recycled crushed stone as a recycled material and reused, which will create new problems with asbestos contamination of the recycled crushed stone.

Therefore, in order to prevent such new problems from occurring, it was necessary to completely remove all of the asbestos-containing paint remaining on the exterior concrete walls of the above buildings before the buildings were demolished.

For this purpose, conventionally, the concrete surface of the exterior wall from which the exterior paint has been removed as described above has been further polished with a polishing device such as an electric grinder to polish and remove any remaining exterior paint on the concrete surface, or a high-pressure washer has been used to spray high-pressure water to wash and remove the exterior paint remaining on the concrete surface of the exterior wall. As with the removal work using the stripping agent described above, these remaining exterior paint removal operations are carried out on the entire surface of the building on which the asbestos-containing exterior wall paint has been applied.

To the best of the applicant's knowledge, there are no patent documents or other documents disclosing these conventional techniques for removing asbestos-containing exterior wall paint.

none

However, all of these asbestos removal methods have the following problems, and there is a strong demand for the development of a new method for removing exterior wall paint.

In other words, the former polishing and removal work is slow and must be done at least twice for the entire surface of the building that has been coated with asbestos-containing exterior paint. For this reason, the polishing and removal work requires more time and effort than the previous peeling and removal work described above, which leads to a significant increase in work costs.

The latter cleaning and removal work using high-pressure water is also carried out on the entire surface of a building that has been coated with asbestos-containing exterior paint, but it takes less time than the above-mentioned polishing and removal work. However, the high-pressure cleaner used is a very expensive device, which also leads to a rise in work costs.

The present invention was made in consideration of these conventional problems, and its purpose is to provide a method for removing asbestos-containing exterior wall paint that prevents the exterior wall paint from turning into dust and scattering into the atmosphere during the work of removing the exterior wall paint, which is a pre-process before the demolition of a building, and that can completely remove all of the exterior wall paint from the main body of the building, while also requiring a short work time and low work costs.

Another object of the present invention is to provide an asbestos-containing exterior paint removal device that can be suitably used in the above-mentioned exterior paint removal method.

The present invention was made as a result of various experimental research conducted by the inventors based on the following viewpoints:

In other words, the inventors have focused on the fact that in the method of removing exterior wall paint using the above-mentioned paint stripper, when the asbestos-containing exterior wall paint is moistened and softened, it becomes easier to peel and remove from the main body of the building, but because some of the exterior wall paint remains on the surface of the building, additional removal work is required to completely remove this remaining exterior wall paint, and as a result, a large-scale exterior wall paint removal work spanning two stages is indispensable.

Specifically, in light of the fact that the main purpose and effect of the stripping agent used in the first exterior paint removal work, which is to moisten and soften the exterior paint, was causing a new problem of asbestos-containing exterior paint penetrating and remaining on the exterior concrete surface of the building itself, in order to reduce the amount of work required for the large-scale exterior paint removal work that previously took place in two stages and to cut work costs, we focused on the need to prevent the exterior paint from turning into dust and scattering into the atmosphere, while at the same time completely removing all of the exterior paint from the building itself, without using the stripping agent.

In order to realize such a removal method, the inventors conducted various tests and research, and also analyzed and examined the structural characteristics of asbestos-containing exterior wall paints. As a result, they noticed that typical asbestos-containing exterior wall paints are made of elastic paints, which are highly stretchable, resilient, and waterproof, and that exterior wall paints made of such elastic paints do not lose the properties of the elastic paint significantly even with deterioration over time, and are particularly resistant to tearing. Then, based on the knowledge thus obtained, they conducted further tests and research, which led to the completion of this invention.

That is, in order to achieve the above-mentioned object, the method for removing asbestos-containing exterior wall paint of the present invention is a method for continuously peeling off the asbestos-containing exterior wall paint formed on the exterior concrete surface of a building body by utilizing the elastic properties of the exterior wall paint and performing continuous striking operations of a removing tool while the tip of the tool is abutted against the exterior wall paint at a predetermined inclination angle, and is characterized in that the removing tool is a tip tool provided at the tip of a hand-held electric impact device and is configured to perform striking operations by forward and backward vibrations applied from the impact device .

As a preferred embodiment, the following configuration is adopted.
(1) When the exterior wall paint has a thickness equal to or greater than a predetermined standard thickness, the elastic properties of the exterior wall paint itself are utilized to perform the striking action by the peeling tool.

(2) If the exterior wall paint has a thickness less than the predetermined standard thickness, as a pre-process, an additional elastic paint is applied to the surface of the exterior wall paint to give the exterior wall paint a thickness equal to or greater than the predetermined standard thickness, and then the elastic properties of the exterior wall paint itself that has been given this thickness are utilized to perform the striking action with the peeling tool.

(3) The peeling tool is a tip tool attached to the tip of a handheld electric impact device, and is configured to perform impact operations using forward and backward vibrations applied by the impact device.

(4) The peeling tool is structured so that it can be attached to the tip of the electric impact device in a removable and replaceable manner, and multiple types of peeling tools having cutting edges of different shapes and dimensions can be prepared as replacement attachments.

(5) The inclination angle θ of the cutting edge of the removing tool when the cutting edge is in contact with the exterior wall paint is set to 15°≦θ≦45°.

(6) The above-mentioned predetermined reference thickness is set to a size that allows the cutting edge of the above-mentioned removal tool to engage with the cross-sectional portion of the above-mentioned exterior wall paint.

The asbestos-containing exterior wall paint removal device of the present invention is a device for removing asbestos-containing exterior wall paint formed on the exterior concrete surface of a building body, and is characterized in that it is equipped with a removal tool at the tip of a hand-held electric impact device, and that this removal tool is configured to perform an impact operation by forward and backward vibrations applied from the impact device.

In a preferred embodiment, the peeling tool is structured to be detachably and replaceably attached to the tip of the electric impact device, and multiple types of peeling tools with cutting edges of different shapes and dimensions are prepared as replacement attachments.

The method for removing asbestos-containing exterior wall paint of the present invention utilizes the elastic properties of the exterior wall paint, and by abutting the tip of a removing tool against the exterior wall paint at a predetermined inclination angle and performing continuous impact operations with the removing tool, the removing tool being a tip tool attached to the tip of a hand-held electric impact device and configured to perform impact operations by forward and backward vibrations applied from the impact device, it is possible to obtain the unique effects listed below, and during the work of removing the exterior wall paint of a building, it is possible to prevent the exterior wall paint from turning into dust and scattering into the atmosphere, and it is possible to completely remove all of the exterior wall paint from the building body, and it is possible to provide a method for removing asbestos-containing exterior wall paint which requires short working hours and low working costs.

(1) By performing continuous striking motions with the peeling tool while the tip of the peeling tool is pressed against the exterior wall paint at a predetermined inclination angle, the exterior wall paint is smoothly and reliably peeled and removed continuously from the exterior concrete surface of the building body by the tip of the peeling tool due to its own elastic properties.

In other words, unlike the use of conventional paint removers, the inherent properties of the exterior wall paint are not changed, and as a result, the inherent elastic properties of the exterior wall paint, particularly its stretchability and resilience, are effectively utilized, and even with the peeling force of the peeling tool, the paint is not broken down or crushed into small pieces, but is smoothly and reliably peeled off from the exterior concrete surface of the building body in a continuous connected state, and the exterior wall paint does not break into dust and scatter into the air during the peeling work.

Furthermore, as mentioned above, the exterior wall paint is peeled off in one piece without tearing due to its elastic properties, so it can be completely removed without remaining on the exterior wall concrete surface.

(2) By performing continuous striking motions with the peeling tool while the tip of the peeling tool is pressed against the exterior wall paint at a predetermined inclination angle, the exterior wall paint is forcibly and continuously peeled off from the exterior wall concrete surface due to its integrity based on its inherent elastic properties, against its adhesive force to the exterior wall concrete surface.

(3) By striking the exterior wall paint with a thickness equal to or greater than a predetermined standard thickness, specifically a thickness that the cutting edge of the peeling tool being used can engage, the peeling force of the cutting edge can be applied reliably and effectively to the exterior wall paint, thereby more effectively achieving the effect of (2) above.

(4) By setting the thickness of the exterior wall paint to a standard thickness or greater that allows the cutting edge of the removal tool to engage with the cross-sectional portion of the exterior wall paint, the cutting edge of the removal tool can securely grip the exterior wall paint, effectively removing it from the exterior wall concrete surface.

(5) The above-mentioned peeling tool is a tip tool attached to the tip of a hand-held electric impact device, and is configured to perform an impact action by the forward and backward vibrations applied by the impact device. This allows the large impact force of the tip tool to act on the exterior wall paint, effectively exerting the effect of the cooperative action with the elastic properties of the exterior wall paint, allowing the exterior wall paint to be peeled off smoothly and reliably from the exterior wall concrete surface.

(6) According to the asbestos-containing exterior wall paint removal device of the present invention, the asbestos-containing exterior wall paint removal method of the present invention can be carried out reliably and effectively, and the unique effects of (1) to (5) above can be achieved.

1A and 1B show the state of carrying out a method for removing asbestos-containing exterior wall coating according to a first embodiment of the present invention, with FIG. 1A showing the state of removing upward, and FIG. 1B showing the state of removing downward. The relationship between the cutting edge of the peeling tool and the exterior wall paint when the removal method is being implemented is shown diagrammatically. Figure 2(a) shows the initial state in which the cutting edge of the peeling tool is thrust into the exterior wall paint, and Figure 2(b) shows the state in which the exterior wall paint is peeled off and removed by the impact motion of the cutting edge of the peeling tool. FIG. 2 is a front cross-sectional view showing an enlarged cross-sectional structure of an exterior wall coating to which the removal method is applied. FIG. 4(b) is a perspective view of a peeling tool used in the removal method, and FIG. 4(c) is a perspective view of a peeling tool used in the removal method, in which FIG. 4(a) is an overall perspective view, FIG. 4(b) is a perspective view of a peeling tool having a single-edged tip, and FIG. 4(c) is a perspective view of a peeling tool having a double-edged tip. 5(a) to (c) are perspective views showing different shapes of the cutting edge of the peeling tool. FIG. 2 is a perspective view showing an electric impact device equipped with the peeling tool as an end tool. FIG. 1 is a perspective view showing an example of an old and dilapidated building prior to demolition work, which is the subject of the method for removing asbestos-containing exterior wall paint of the present invention. FIG. 8 is an enlarged front cross-sectional view corresponding to FIG. 3, showing the cross-sectional structure of the exterior wall paint that is the target of the method for removing asbestos-containing exterior wall paint in accordance with embodiment 2 of the present invention. FIG. 8(a) shows the current cross-sectional structure of the exterior wall paint, and FIG. 8(b) shows the cross-sectional structure after an elastic paint has been applied over it prior to carrying out this removal method. Figure 9(b) is a photograph of the exterior concrete surface after the exterior wall paint has been peeled off and removed with a stripping tool using a conventional method for removing asbestos-containing exterior wall paint, and Figure 9(a) is an enlarged view of a portion of the exterior concrete surface from which the exterior wall paint has been peeled off. 1 is a photograph showing the state when the method for removing asbestos-containing exterior wall paint according to the first embodiment of the present invention is carried out. This is a photograph taken of the state of an exterior wall coating made of elastic lysine, which is the target for removal by the method for removing asbestos-containing exterior wall coating according to embodiment 2 of the present invention, when successive striking operations are applied with a removal tool. This is a photograph showing the state of the exterior wall paint when an additional elastic paint is applied to the surface of the exterior wall paint formed from the same elastic lysine, and the thick exterior wall paint is subjected to successive striking motions with a removal tool.

The following describes in detail an embodiment of the present invention with reference to the drawings. Note that the same reference numerals throughout the drawings indicate the same components or elements.

EMBODIMENT 1
The method for removing asbestos-containing exterior wall coating according to the present invention is shown in Figs. 1 to 7. Specifically, this removal method is for removing the exterior wall coating 1 of a building B as a pre-process in the demolition work of an old and deteriorated building B as shown in Fig. 7.

The above-mentioned exterior wall coating 1 is applied to the exterior wall of an old building B, that is, the surface Ca of the exterior concrete wall C. Most exterior wall coatings 1 contain asbestos, which has excellent fire resistance, heat resistance, soundproofing, etc. However, since this asbestos dust is harmful to the human body, it is necessary to prevent the asbestos dust from scattering into the air even during the removal work.

The method for removing the exterior wall paint 1 in this embodiment utilizes the elastic properties of the exterior wall paint 1, and when carrying out this method, a removal tool 2 that performs a striking motion is preferably used, as shown in Figure 1.

This peeling tool 2 is rod-shaped as shown in Figure 4, with a cutting edge 3 at its tip and a shank 4 at its rear end, and is in the form of a tip tool that can be detachably and replaceably attached to the tip 6 of an electric impact device 5 as shown in Figure 6.

Specifically, the shank portion 4 of the peeling tool 2 and the tip portion 6 of the electric impact device 5 are connected to each other in a corresponding manner, and the shank portion 4 is removably inserted and fixed to the tip portion 6.

The cutting edge 3 of the peeling tool 2 is in the form of a wide, flat chisel as shown in the figure. The tip 3a of the cutting edge 3 can be either a single-edged tip as shown in FIG. 4(a) or a double-edged tip as shown in FIG. 4(b). In the illustrated embodiment, a peeling tool 2 having a single-edged cutting edge 3 as shown in FIG. 4(a) is used.

The electric impact device 5 has a shape and dimensions that allow it to be operated by hand, and although not specifically shown, the device body 7 has a drive unit such as an electric motor and a drive mechanism built in, and is equipped with a conventionally known electric mechanical structure that applies a striking action by forward and backward vibration to the peeling tool 2 attached to the tip 6. In FIG. 6, 8 indicates a grip that is held by the user, 9 indicates a drive switch, and 10 indicates a power cord.

In other words, the electric impact device 5 can be replaced by an electric impact device such as a conventional commercially available electric hammer or electric hammer driver, and in that case, the connection structure of the shank portion 4 of the stripping tool 2 is appropriately designed and set to correspond to the connection structure of the tip portion 6 of the electric impact device 5 to be used.

As described below, the specific shape and structure of the peeling tool 2 is not particularly limited as long as the cutting edge 3 can effectively peel off the exterior wall paint 1 by the impact action provided by the electric impact device 5. For example, as shown in Figures 5(a) to (c), it is effective to prepare multiple types of peeling tools 2A, 2B, and 2C having cutting edges 3A, 3B, and 3C of different shapes and dimensions according to the location and purpose of use as replacement attachments, and to use these peeling tools 2A, 2B, and 2C interchangeably as appropriate.

When using the peeling tool 2, as shown in FIG. 2, the cutting edge 3 of the peeling tool 2 is pressed against the exterior wall paint 1 (as shown in FIG. 2(a)), and the electric impact device 5 is driven. At this time, the inclination angle θ of the cutting edge 3 is preferably set to 15°≦θ≦45°, as described below.

The inclination angle θ of the cutting edge 3 is set so as to effectively utilize the elastic properties of the exterior wall paint 1, since the asbestos-containing exterior wall paint 1 is made of an elastic paint, and the exterior wall paint 1 formed from such an elastic paint maintains its elastic properties even when deteriorated over time.

In other words, the cross-sectional structure of a typical exterior wall coating 1 has a cross-sectional structure consisting of multiple elastic coatings (elastic paint layers) 11, as shown in Figure 3, for example. Specifically, the surface Ca of the exterior wall concrete C is coated in layers with a base preparation paint 11a, a primer 11b, a main material (base layer) 11c, a main material (pattern) 11d, and a topcoat 11e in that order.

The cross-sectional structure of the exterior wall coating 1 shown in Figure 3 is an example of the exterior wall coating 1 applied to the exterior concrete C of an old building B. Other exterior wall coatings 1 have different specific cross-sectional structures, but all exterior wall coatings 1 are essentially the same in that they are made up of multiple elastic paint layers 11, do not lose their elastic paint properties significantly even with deterioration over time, and have elastic properties that make them particularly resistant to tearing.

The inventors have found through repeated testing that the elastic properties of the exterior wall coating 1 can be utilized to perform successive striking operations with the peeling tool 2, thereby allowing the exterior wall coating 1 to be continuously peeled off from the surface Ca of the exterior wall concrete C.

Next, we will explain in detail the specific conditions for effectively peeling and removing the exterior wall coating 1 from the surface Ca of the exterior wall concrete C using the above-mentioned peeling tool 2.

First, as described above, when using the stripping tool 2 to remove the exterior wall paint 1, the electric impact device 5 is driven while the cutting edge 3 of the stripping tool 2 is abutted against the surface 1a of the exterior wall paint 1, as shown in FIG. 2(a). At this time, the inclination angle θ of the cutting edge 3 must be in the range of 15°≦θ≦45°.

This inclination angle θ is the condition for smoothly and reliably peeling the elastic exterior wall coating 1 from the surface Ca of the exterior wall concrete C by the striking force of the cutting edge 3 of the peeling tool 2. When the peeling tool 2 performs continuous striking operations under this condition, as shown in FIG. 2(b), the cutting edge 3 bites into the boundary between the exterior wall coating 1 and the surface Ca of the exterior wall concrete C, and the exterior wall coating 1 is smoothly and reliably peeled off from the surface Ca of the exterior wall concrete C without being crushed due to its elasticity (see exterior wall coating 12). Moreover, the peeled exterior wall coating 12 is peeled off in a continuous strip shape without breaking due to its elasticity (see FIG. 1(a) or FIG. 1(b)), and does not disperse into the atmosphere due to dusting. In addition, it is preferable to use the uneven pattern formed by the main material (pattern) 11d as a trigger for the cutting edge 3 to enter the exterior wall coating 1, as this makes it easier for the cutting edge 3 to enter.

On the other hand, if the inclination angle θ of the cutting edge 3 is less than 15°, the cutting edge 3 will not bite into the boundary between the exterior wall paint 1 and the surface Ca of the exterior wall concrete C, and will escape to the exterior wall paint 1 side, resulting in the exterior wall paint 1 being broken into pieces despite its elastic properties, with the risk of the powder dispersing into the atmosphere.

Conversely, if the inclination angle θ of the cutting edge 3 is greater than 45°, the cutting edge 3 will directly strike the exterior wall concrete C, cutting and destroying the exterior wall concrete C itself as in general chipping work, resulting in more work time than necessary being required to peel and remove the exterior wall paint 1, resulting in extremely poor work efficiency.

Next, the above-mentioned exterior wall coating 1 must have a thickness _T1 equal to or greater than a predetermined standard thickness _T0 . This condition is essential so that the impact force of the peeling tool 2 can effectively act on the exterior wall coating 1 to reliably peel the exterior wall coating 1 from the surface Ca of the exterior wall concrete C.

Specifically, the predetermined reference thickness _T0 is set to a size at which the cutting edge 3 of the peeling tool 2 to be used engages with the cross-sectional portion of the exterior wall coating 1. In other words, the predetermined reference thickness T0 is set to a size at which an engagement state is obtained in which the cutting edge 3 of the peeling tool 2 effectively applies its impact force to the exterior wall coating 1.

In other words, since the thickness _T1 of the exterior wall coating 1 of most conventional buildings B is generally about 1.0 to 2.0 mm, conversely, if the tip thickness of the blade 3 of the removing tool 2 is set to a size that allows it to engage with the cross-sectional portion of the exterior wall coating ₁ of thickness T1 in the above-mentioned engagement state, then in principle, the impact force of the removing tool 2 will effectively act on all general exterior wall coating 1, and it will be possible to reliably remove it from the surface Ca of the exterior wall concrete C.

On the other hand, when the thickness T1 of the exterior wall coating ₁ is smaller than the reference thickness _T0 , it is peeled off and removed by the removal method of the second embodiment described later.

In the method for removing exterior wall paint configured as described above, the electric impact device 5 is driven to perform an impact motion of the stripping tool 2, while the cutting edge 3 is thrust against the exterior wall paint 1 as shown in FIG. 2(a) and then moved forward, so that the cutting edge 3 continues to perform an impact motion, thereby continuously peeling off the exterior wall paint 1 from the surface Ca of the exterior wall concrete C of the building B body.

Specifically, as shown in Figure 2(b), the cutting edge 3 of the removing tool 2 bites into the adhesive boundary between the exterior wall coating 1 and the surface Ca of the exterior wall concrete C, and the continuous impact force caused by the back and forth vibration smoothly and reliably removes the exterior wall coating 1 from the surface Ca of the exterior wall concrete C. At the same time, the removed exterior wall coating 12 is peeled off in a continuous strip as shown in the figure without breaking due to its elastic properties, and is not dispersed into the atmosphere by turning into dust.

When the cutting edge 3 of the removing tool 2 bites into the adhesive boundary between the exterior wall coating 1 and the surface Ca of the exterior wall concrete C, the cutting edge 3 actually peels off and removes the entire exterior wall coating 1 while slightly scraping off the surface Ca of the exterior wall concrete C at the adhesive boundary between the exterior wall coating 1 and the surface Ca of the exterior wall concrete C. As a result, the entire elastic coating layer 11 including the base preparation coating 11a shown in FIG. 3 is reliably peeled off and removed from the surface Ca of the exterior wall concrete C, and no exterior wall coating 1 remains on the surface Ca of the exterior wall concrete C.

This situation is not like conventional chipping work, in which the cutting edge 3 directly strikes the exterior wall concrete C, cutting and destroying the exterior wall concrete C itself, but rather peels off and removes the entire exterior wall coating film 1 while slightly chipping off the surface Ca of the exterior wall concrete C at the adhesive boundary between the exterior wall coating 1 and the surface Ca of the exterior wall concrete C. Therefore, the load on the peeling tool 2 at this time is much smaller than the load applied during conventional chipping, the burden on the worker is not that great, the work time is short, and the work efficiency is very good.

By performing the above steps, the exterior wall paint 12 (see Figures 1(a) and (b)) with a width dimension corresponding to the tip width of the blade 3 of the peeling tool 2 is peeled off and removed. By repeating the same steps while sequentially shifting the blade 3 of the peeling tool 2 in the width direction, all of the exterior wall paint 1 of building B is peeled off and removed.

As described above in detail, the exterior wall paint removal method of this embodiment provides the unique effects listed below.

(a) With the cutting edge 3 of the peeling tool 2 pressed against the exterior wall coating 1 at a predetermined inclination angle θ (15°≦θ≦45°), the peeling tool 2 performs continuous striking motions, and the exterior wall coating 1 is smoothly and reliably peeled and removed continuously from the surface Ca of the exterior wall concrete C of the building B body by the cutting edge 3 of the peeling tool 2 due to its own elastic properties.

In other words, unlike the use of conventional paint strippers, the inherent properties of the exterior wall coating 1 are not changed, and as a result, the inherent elastic properties of the exterior wall coating 1, which is made of an elastic paint, particularly its resistance to tearing due to its stretchability and resilience, are effectively utilized, and the coating is smoothly and reliably peeled off from the surface Ca of the exterior wall concrete C of the building B body in a continuous connected state (exterior wall coating 12) without being broken into small pieces or crushed by the peeling force (impact force) of the peeling tool 2, and the exterior wall coating 1 does not break down into dust and scatter into the air during the peeling operation.

Moreover, as described above, the exterior wall coating 1 can be peeled off in one piece without breaking due to its elastic properties, and can therefore be completely removed without remaining on the surface Ca of the exterior wall concrete C.

(b) With the cutting edge 3 of the peeling tool 2 pressed against the exterior wall coating 1 at a predetermined inclination angle θ, the peeling tool 2 is subjected to continuous striking motions, whereby the exterior wall coating 1 is forcibly and continuously peeled off and removed from the surface Ca of the exterior wall concrete C, due to its integrity based on its inherent elastic properties, against the adhesive force to the surface Ca of the exterior wall concrete C.

(c) By performing an impact operation with the peeling tool 2 against the exterior wall paint 1 having a predetermined reference thickness _T0 , specifically a thickness that is large enough for the cutting edge 3 of the peeling tool 2 to engage, the peeling force of the cutting edge 3 acts reliably and effectively on the exterior wall paint 1, thereby making it possible to more effectively achieve the effect of (b) above.

(d) By setting the thickness T1 of the exterior wall coating ₁ to be equal to or greater than the reference thickness _T0 at which the cutting edge 3 of the peeling tool 2 to be used engages with the cross-sectional portion of the exterior wall coating 1, the cutting edge 3 of the peeling tool 2 can securely grip the exterior wall coating 1, effectively exerting the peeling action from the surface Ca of the exterior wall concrete C.

(e) The peeling tool 2 is a tip tool attached to the tip 6 of a handheld electric impact device 5, and is configured to perform an impact action by the forward and backward vibrations applied by the impact device 5. As a result, the large impact force of the peeling tool 2 acts on the exterior wall paint 1, and the effect of the cooperative action with the elastic properties of the exterior wall paint 1 is exerted, so that the exterior wall paint 1 is smoothly and reliably peeled off from the surface Ca of the exterior wall concrete C.

(f) According to the removal device 5 of this embodiment, the removal of the asbestos-containing exterior wall paint 1 of this embodiment can be carried out reliably and effectively, and the unique effects of (a) to (e) above can be achieved.

EMBODIMENT 2
This embodiment is shown in FIG. 8 and is a method for peeling and removing an exterior wall coating 21 having a thickness T2 that does not have the standard thickness _T0 required for the exterior wall coating ₁ described in embodiment 1, using the peeling tool 2 described above.

As described above, most of the exterior wall coatings 1 of the old building B have a thickness _T1 that is equal to or greater than the standard thickness _T0 , and can be peeled off and removed from the surface Ca of the exterior wall concrete C by the method for removing the exterior wall coating of embodiment 1. However, some exterior wall coatings 21 are thinner than the standard thickness _T0 .

For example, an exterior wall coating formed with lysine (elastic lysine) of elastic paint corresponds to the above-mentioned exterior wall coating 21. Since elastic lysine is applied directly to the surface Ca of the exterior wall concrete C without a base coat or the like, its thickness _T2 is inevitably thin (the thickness _T2 of the exterior wall coating 21 actually applied to the building B is about 0.8 mm). Therefore, the exterior wall coating formed with elastic lysine does not meet the essential conditions described in the first embodiment as it is, and the exterior wall coating removal method of the first embodiment cannot be carried out.

In other words, when the above-mentioned exterior wall paint 21 is subjected to continuous striking motions by the stripping tool 2, the exterior wall paint 21 is not peeled off from the surface Ca of the exterior wall concrete C, but is broken and crushed by the striking force of the stripping tool 2, and it was found that the exterior wall paint removal method of embodiment 1 cannot be carried out at all.

In this way, with the exterior wall paint 21 having a thin thickness _T2 , the impact force of the blade 3 of the peeling tool 2 cannot be used effectively to peel it off from the surface Ca of the exterior wall concrete C. Furthermore, since the thickness _T2 of the exterior wall paint 21 is thinner than the above-mentioned standard thickness _T0 , it has poor elastic properties and is easily torn, so that the exterior wall paint 21 is broken into pieces by the impact force of the blade 3 of the peeling tool 2, which causes the exterior wall paint 21 to disperse into dust and be dispersed into the atmosphere.

As a result of further testing and research on this point, the inventors have discovered that even with the above-mentioned exterior wall coating 21, by applying an additional elastic coating 22 to the surface 21a to increase the thickness, as shown in Figure 8 (b), and imparting this exterior wall coating 21 with a thickness _T3 equal to or greater than the above-mentioned reference thickness _T0 , the exterior wall coating 23 imparted with this thickness can have elastic properties equivalent to the elastic properties of general exterior wall coating 1 (embodiment 1), and have completed the exterior wall coating removal method of this embodiment.

That is, in this embodiment, as a pre-step before carrying out the removal work by the peeling tool 2, as shown in FIG. 8(b), an additional elastic paint 22 is applied once again to the surface 21a of the exterior wall paint 21, thereby giving the exterior wall paint 21 a thickness _T3 equal to or greater than the reference thickness _T0 , so that the impact force of the cutting edge 3 of the peeling tool 2 acts effectively on the exterior wall paint 21 and the exterior wall paint 21 has sufficient elastic properties. Then, the elastic properties of the thickly applied exterior wall paint 23 itself are utilized to perform the impact operation by the peeling tool 3.

As described above, the desired results can be obtained by applying additional elastic paint 22 to the surface 21a of the exterior wall paint 21 only once, and even if it is applied twice or more, the effect is the same as that obtained by applying only one coat. In conclusion, it has been found that a single coat as described above is sufficient.

According to the method for removing exterior wall paint of this embodiment, similarly to the removal method in embodiment 1, the exterior wall paint 23 (exterior wall paint 21 + elastic paint 22) can be continuously peeled off and removed from the surface Ca of the exterior wall concrete C of the building B body by using the peeling tool 2 of the electric impact device 5, and the peeled exterior wall paint 23 (exterior wall paint 21 + elastic paint 22) is peeled off in a continuous band shape without breaking due to its elastic properties, and is not dispersed into the atmosphere by turning into dust.
The other configurations and operations are the same as those of the first embodiment.

The present invention will be described in more detail below with reference to examples and comparative examples, but these are not intended to limit the scope of the present invention in any way.

Example 1
Fig. 9 is a photograph of the exterior concrete surface when the exterior wall paint is peeled off with a peeling tool in the method of removing asbestos-containing exterior wall paint using the conventional paint peeling agent mentioned in the background art of the present invention. The exterior wall paint 1a peeled off with the peeling agent is the paint that bulges outward from the exterior wall concrete surface Ca of the building body when the peeling agent penetrates the exterior wall paint and the exterior wall paint 1 becomes moist and soft, and is peeled off. The masking tape M was used to divide the areas of the exterior wall used in the study of this example, and the same applies to the following examples.

Figure 9 (b) is a photograph of an enlarged portion of the exterior wall concrete surface from which the exterior wall paint in Figure 9 (a) has been peeled off. Although there are some areas where the concrete surface Ca is exposed, as shown in the area circled in the enlarged photograph, with this removal method, even after the exterior wall paint 1a has been peeled off with a peeling tool, some of the asbestos-containing exterior wall paint 1b has penetrated and become clogged in small depressions on the exterior wall concrete surface Ca, and the asbestos contained in this exterior wall paint also remains on the building surface.

In addition, when the asbestos content near the surface Ca of the exterior wall concrete C after removing the exterior wall coating 1a peeled off with the stripping agent in Figure 9 was analyzed (analysis method: JIS A1481-1), the analysis results showed that the estimated asbestos mass fraction was greater than 0.1% and less than 5.0%. In other words, it was found that the asbestos could not be removed because the exterior wall coating 1a remained in the small depressions on the exterior wall concrete surface Ca and had penetrated and clogged them. In addition, it is difficult to manually scrape off and remove the exterior wall coating 1a that had penetrated and clogged the small depressions on the exterior wall concrete surface Ca, and the remaining asbestos could not be removed without using the method of grinding with a grinding device such as the electric grinder mentioned above, or a high-pressure washer that sprays high-pressure water.

In contrast, Figure 10 is a photograph of the state when the asbestos-containing exterior wall paint removal method according to embodiment 1 of the present invention was applied to the same exterior wall paint. As is clear from this photograph, the exterior wall paint 1 is reliably peeled off from the surface Ca of the exterior wall concrete C by the continuous impact force of the blade 3 of the peeling tool 2, and the peeled exterior wall paint 12 is peeled off in a continuous band as shown in the photograph without breaking due to its elastic properties.

Example 2
Figure 11 is a photograph taken of the state when a stripping tool 2 is applied with successive striking operations to an exterior wall coating 21 formed from elastic lysine, which is an example of an exterior wall coating to be removed by the method for removing asbestos-containing exterior wall coating according to embodiment 2 of the present invention. As is clear from this photograph, not only can the exterior wall coating 21 not be peeled off from the surface Ca of the exterior wall concrete C, but as shown by the oval circle, the exterior wall coating 21 is broken into pieces, turns into dust and scatters.

In contrast, Fig. 12 is a photograph of the state when an additional elastic paint 22 is applied once to the surface 21a of the above-mentioned exterior wall paint 21 as shown in Fig. 8(b), and the thickly applied exterior wall paint 23 is subjected to continuous impact motions by the stripper 2. As is clear from this photograph, by performing impact motions with the stripper tool 2, the exterior wall paint 23 (exterior wall paint 21 + elastic paint) is peeled off and removed from the surface Ca of the exterior wall concrete C by the stripper tool 2 of the electric impact device 5, as in the removal method in embodiment 1, and the peeled exterior wall paint 23 (exterior wall paint 21 + elastic paint) is peeled off in a continuous strip shape without breaking due to its elastic properties.

Example 3
When the asbestos concentration in the air in the work environment at the work site was actually measured when the asbestos-containing exterior wall paint removal methods of embodiment 1 and embodiment 2 were applied to asbestos-containing exterior wall paint, it was found that the asbestos dust concentration was 0.3 f/L or less and was unmeasurable, which was equivalent to the asbestos concentration in general air (approximately 0.1 to 0.3 f/L) and was significantly below the permissible limit for air pollution (10 f/L) under the Air Pollution Control Act.

Example 4
When the asbestos-containing exterior wall paint removal methods according to embodiment 1 and embodiment 2 were applied to asbestos-containing exterior wall paint, the asbestos content near the surface Ca of the exterior wall concrete C from which the exterior wall paint had been peeled off and removed was analyzed (analysis method: JIS A1481-1).The analysis results showed that the estimated asbestos mass fraction was 0.1% or less, meaning that there was essentially no remaining asbestos.

The above-described embodiment merely shows a preferred embodiment of the present invention, and the present invention is not limited to this embodiment, and various design changes are possible within the scope of the embodiment.

For example, in the illustrated embodiment, in addition to the peeling tool 2, the peeling tools 2A, 2B, and 2C illustrated in Figures 5(a) to (c) are prepared as replacement attachments, and are used interchangeably as appropriate. However, as described above, as long as the same function can be achieved, that is, as long as the impact action provided by the impact device 5 can effectively peel the exterior wall paint 1 with the cutting edge of the peeling tool, the specific shape and structure are not particularly limited, and the design can be changed to a peeling tool having a cutting edge with a shape and dimensions other than those of the illustrated embodiment.

B Building C Exterior wall concrete Ca Surface of exterior wall concrete _T1 , _T2 , _T3 Thickness of exterior wall paint _T0 Reference thickness of exterior wall paint t Tip thickness of peeling tool blade 1 Exterior wall paint 2, 2A, 2B, 2C Peeling tool 3, 3A, 3B, 3C Tip of peeling tool 4 Shank of peeling tool 5 Electric impact device 6 Tip of electric impact device 7 Body of electric impact device 12 Peeled exterior wall paint 21 Exterior wall paint 22 Additional overcoat elastic paint 23 Thickly applied exterior wall paint

Claims (6)

A method for continuously peeling off an asbestos-containing exterior wall paint formed on the concrete surface of a building body, by utilizing the elastic properties of the exterior wall paint and performing continuous striking operations of a peeling tool while a cutting edge of the peeling tool is abutted against the exterior wall paint at a predetermined inclination angle, comprising:
The peeling tool is a tip tool provided at the tip of a hand-held electric impact device, and is configured to perform an impact operation by forward and backward vibrations applied from the impact device ,
The striking action causes the cutting edge to slightly scrape the concrete at the adhesion boundary between the exterior wall coating and the concrete surface while peeling and removing the exterior wall coating.
A method for removing asbestos-containing exterior wall paint. A method for removing asbestos-containing exterior wall paint, as described in claim 1, characterized in that when the exterior wall paint has a thickness equal to or greater than a predetermined standard thickness, the elastic properties of the exterior wall paint itself are utilized to perform the striking action with the peeling tool. The method for removing asbestos-containing exterior wall paint described in claim 1, characterized in that, when the exterior wall paint has a thickness smaller than a predetermined standard thickness, as a pre-step, an additional elastic paint is applied to the surface of the exterior wall paint to give the exterior wall paint a thickness equal to or greater than the predetermined standard thickness, and then the striking action is performed with the peeling tool by utilizing the elastic properties of the exterior wall paint itself that has been given this thickness. The method for removing asbestos-containing exterior wall paint as described in claim 1, characterized in that the removal tool is structured to be removable and replaceable at the tip of the electric impact device, and multiple types of the removal tool having cutting edges of different shapes and dimensions are prepared as replacement attachments. A method for removing asbestos-containing exterior wall paint as described in claim 1, characterized in that the inclination angle θ of the cutting edge of the removing tool when the cutting edge is pressed against the exterior wall paint is set to 15°≦θ≦45°. A method for removing asbestos-containing exterior wall paint as described in claim 2 or 3, characterized in that the specified standard thickness is set to a size such that the cutting edge of the peeling tool used engages with the cross-sectional portion of the exterior wall paint.

Images