Film formation method

Abstract

To provide a coating film forming method and a coating film forming agent capable of suppressing a surfing phenomenon of wiring / piping materials, and facilitating the extracting the wiring / piping materials from an underground pipe.SOLUTION: A coating film forming method with respect to an underground pipe 11 embedded in the ground UG and wiring 12 inserted in the underground pipe 11, includes: an adhering step for adhering a coating film forming agent 14 including a resin dispersion liquid in which water-insoluble resin is dispersed to an inner surface 11c of the underground pipe 11 and an outer surface 12a of the wiring 12; and a drying step for drying the adhered coating film forming agent 14. The resin dispersion liquid can form a resin coating with adhesion strength which can be peeled when film forming temperature is 0 degree or more and the adhesion between the underground pipe 11 and the wiring 12 is 2 N / cm or less.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a method for forming a coating on an underground pipe and a wiring / piping material inserted into the underground pipe. By law Regarding. [Background technology]

[0002] In recent years, for the purpose of improving safety and improving the beauty of towns, underground buried boxes are connected by underground buried pipes buried underground, and wiring and piping materials are inserted into the underground buried pipes. The surf-riding phenomenon is a problem with wiring and piping materials inserted into underground buried pipes. The surf-riding phenomenon is a phenomenon in which wiring and piping materials in underground buried pipes move in the direction of travel of a vehicle when the vehicle runs on the ground. If tension is applied to the wiring and piping materials or the wiring and piping materials are bent due to the surf-riding phenomenon, the wiring and piping materials may be damaged. In order to restrain the movement of the wiring and piping materials due to the surf-riding phenomenon, in Patent Document 1, the wiring and piping materials are clamped by a cleat in the underground buried box on the side where the wiring and piping materials are pulled.

[0003] In addition, problems may occur in that small animals such as termites and mice chew on underground pipes and wiring / piping materials, causing damage to the underground pipes and wiring / piping materials. In order to suppress damage to underground pipes and wiring / piping materials, small animals are controlled. In Patent Document 2, small animals are controlled by filling a water-absorbent polymer that has absorbed a water-soluble anti-termite agent between an underground pipe and a wiring / piping material. In Patent Document 3, small animals are controlled by pouring a soft polyvinyl chloride resin material containing a rodent repellent and / or an anti-termite agent into a gap through which mice and termites enter, and then solidifying the material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-39402 A [Patent Document 2] JP 2009-011128 A [Patent Document 3] Japanese Patent Application Publication No. 3-109301 Summary of the Invention [Problem to be solved by the invention]

[0005] However, since underground pipes are generally several tens to several hundreds of meters long, even if the wiring and piping materials are clamped inside an underground buried box, it is difficult to fully suppress the surfing phenomenon of the wiring and piping materials inside the underground pipes.

[0006] Incidentally, during renovation work, wiring and piping materials may be pulled out from underground pipes. When small animals are controlled by the method disclosed in Patent Document 2 or Patent Document 3, it is necessary to remove the water-absorbent polymer or soft polyvinyl chloride resin material filled between the underground pipe and the wiring and piping material before pulling out the wiring and piping material from the underground pipe. The water-absorbent polymer or soft polyvinyl chloride resin material must be removed over a length of several tens to several hundreds of meters, which is the length of the underground pipe. Removing the water-absorbent polymer or soft polyvinyl chloride resin material over a long distance has been an obstacle to the progress of construction work. [Means for solving the problem]

[0007] The coating forming method for solving the above problems is a coating forming method for an underground pipe buried in the ground and for wiring and piping material inserted into the underground pipe, and includes an attachment step of attaching a coating forming agent containing a resin dispersion liquid in which a water-insoluble resin is dispersed to the inner surface of the underground pipe and the outer surface of the wiring and piping material, and a drying step of drying the coating forming agent attached to the inner surface of the underground pipe and the outer surface of the wiring and piping material, wherein the resin dispersion liquid is capable of forming a resin coating having a film-forming temperature of 0 degrees or higher and an adhesive strength of 2 N / cm or less that allows the underground pipe and the wiring and piping material to be peeled off.

[0008] Regarding the coating forming method, the adhesion process may include a filling process of filling the coating forming agent between the inner surface of the underground buried pipe and the outer surface of the wiring / piping material, and a discharging process of discharging the coating forming agent filled in the filling process from between the inner surface of the underground buried pipe and the outer surface of the wiring / piping material.

[0009] Regarding the coating method, in the adhesion step, the coating agent may be in the form of a foam and applied to the inner surface of the underground buried pipe and the outer surface of the wiring / piping material. Regarding the coating film forming method, the coating step may involve coating the coating film forming agent containing water-insoluble microcapsules in which a small animal control component is encapsulated and the resin dispersion.

[0010] The coating agent for solving the above problems is a coating agent for underground pipes buried in the ground and for wiring and piping materials inserted into the underground pipes, which contains a resin dispersion liquid in which a water-insoluble resin is dispersed, and is attached to the inner surface of the underground pipe and the outer surface of the wiring and piping materials, and the resin dispersion liquid is capable of forming a resin coating having a film-forming temperature of 0 degrees or higher and an adhesive strength of 2 N / cm or less between the underground pipe and the wiring and piping materials that allows peeling.

[0011] Regarding the film-forming agent, the viscosity of the resin dispersion may be 10 mPa·s or more and 400 mPa·s or less. Regarding the film-forming agent, said film-forming agent may be in the form of a foam.

[0012] Regarding the film-forming agent, the film-forming agent may also include water-insoluble microcapsules in which the small animal control component is encapsulated. For the film-forming agent, the microcapsules may have a diameter of 1 μm to 10 μm. Effect of the Invention

[0013] According to the present invention, the surfing phenomenon of wiring and piping materials can be suppressed, and the work of pulling out wiring and piping materials from underground buried pipes becomes easier. [Brief description of the drawings]

[0014] [Figure 1] (a) is a diagram of the underground power line, and (b) is an enlarged view of a part of it. [Diagram 2] Cross-sectional view showing the maintenance process. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] (a) is a cross-sectional view showing the underground pipes and wiring after the discharge process, and (b) is an enlarged view of a part of it. [Figure 6] (a) is a cross-sectional view showing the drying process, and (b) is an enlarged view of a part of it. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, one embodiment of the coating film forming method and coating film forming agent will be described with reference to Figs. <Configuration of underground power lines> First, an underground electric line formed by an underground burial box, an underground buried pipe, and wiring will be described.

[0016] As shown in FIG. 1(a), a plurality of underground burial boxes 10 are buried in the ground UG. The underground burial boxes 10 are, for example, hand holes or manholes. The plurality of underground burial boxes 10 are buried in the ground UG at intervals. Two underground burial boxes 10 are illustrated in FIG. 1(a). Hereinafter, when it is necessary to distinguish between the two underground burial boxes 10, one of the underground burial boxes 10 will be referred to as the first underground burial box 10a, and the other underground burial box 10 will be referred to as the second underground burial box 10b. Each underground burial box 10 has a communication hole 10c that opens to the ground G. When construction or inspection is not being performed, the communication hole 10c is closed by a lid (not shown). In addition, each underground burial box 10 has an insertion hole 10d in the side wall.

[0017] An underground buried pipe 11 is buried in the ground UG. The underground buried pipe 11 in this embodiment is made of concrete. A first end 11a of the underground buried pipe 11 is inserted into the insertion hole 10d of the first underground buried box 10a, and a second end 11b opposite to the first end 11a of the underground buried pipe 11 is inserted into the insertion hole 10d of the second underground buried box 10b. That is, the underground buried pipe 11 is provided so as to connect the first underground buried box 10a and the second underground buried box 10b.

[0018] The underground buried pipe 11 is inserted with a wiring 12 as a wiring / piping material. The wiring 12 in this embodiment is a power cable. The sheath of the wiring 12 in this embodiment is made of polyvinyl chloride. The length of the wiring 12 is about several tens to several hundreds of meters. Since the wiring 12 is subjected to gravity, a lower part of the inner surface 11c of the underground buried pipe 11 in the direction of gravity abuts a lower part of the outer surface 12a of the wiring 12 in the direction of gravity. In addition, the lower part of the inner surface 11c of the underground buried pipe 11 in the direction of gravity and the lower part of the outer surface 12a of the wiring 12 in the direction of gravity face each other via a coating 13 described later. The upper part of the inner surface 11c of the underground buried pipe 11 in the direction of gravity and the upper part of the outer surface 12a of the wiring 12 in the direction of gravity are spaced apart. In addition, the wiring 12 is supported by a support not shown in the underground buried box 10.

[0019] An underground electric line is formed by an underground burying tool including an underground burying box 10, an underground burying pipe 11, and wiring 12. As shown in FIG. 1(b), a coating 13 is formed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. In the drawing, the ratio of the thickness of the coating 13 to the diameter of the underground pipe 11 and the wiring 12 is illustrated higher than the actual ratio. The coating 13 includes a water-insoluble resin. The water-insoluble resin in this embodiment is an ether-based polyurethane. The coating 13 in this embodiment also includes microcapsules in which a small animal control component is encapsulated. That is, the coating 13 in this embodiment is a small animal control coating capable of small animal control of the underground pipe 11 and the wiring 12. In this embodiment, termite control is assumed as the small animal control. For this reason, the small animal control component in this embodiment is a neonicotinoid compound. The microcapsules in this embodiment are fine particles having a diameter of 1 to 10 μm. A detailed method for forming the coating 13 will be described later.

[0020] The underground pipe 11 and the wiring 12 are bonded together by a coating 13. More specifically, a portion of the inner surface 11c of the underground pipe 11 that is on the lower side in the direction of gravity and a portion of the outer surface 12a of the wiring 12 that is on the lower side in the direction of gravity are bonded together by a resin contained in the coating 13. The underground pipe 11 and the wiring 12 are bonded together with an adhesive strength that allows the underground pipe 11 and the wiring 12 to be peeled off at 2 N / cm or less. In this embodiment, the underground pipe 11 and the wiring 12 are bonded together with an adhesive strength that allows the underground pipe 11 and the wiring 12 to be peeled off at 1.96 N / cm.

[0021] 2 N / cm is the upper limit of the adhesive strength that can be pulled out by a towing machine of 8 t, assuming that the wiring 12 of the largest diameter generally used is laid over a maximum distance of 200 m between the underground buried boxes 10. In addition, the strength of the underground buried pipe 11 may decrease due to deterioration of the underground buried pipe 11 or multiple operations of recovering the wiring 12, and if the adhesive strength is too high, the underground buried pipe 11 may be damaged, so the adhesive strength is preferably 2 N / cm or less.

[0022] <Film formation method> Next, a method for forming the coating 13 on the inner surface 11c of the underground buried pipe 11 and the outer surface 12a of the wiring 12 will be described.

[0023] Before starting the formation of the coating 13, a preparation step is carried out to prepare the underground buried pipe 11. As shown in FIG. 2, the maintenance process is a process of checking whether or not there is a blockage in the underground pipe 11, and removing the blockage if there is a blockage in the underground pipe 11. In this embodiment, the presence or absence of a blockage in the underground pipe 11 is checked by blowing air into the underground pipe 11. Specifically, after inserting a blower 20 into the first end 11a of the underground pipe 11, air is blown from the blower 20. As a result, air is blown from the first end 11a to the second end 11b in the underground pipe 11. When forming the coating 13 on an already formed underground electric cable line, a sealing material such as mortar may be filled between the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 at the first end 11a and the second end 11b of the underground pipe 11. In this case, the sealing material is removed, and then air is blown by the blower 20.

[0024] When no blockage occurs in the underground pipe 11, wind comes out from the second end 11b of the underground pipe 11. When no blockage occurs in the underground pipe 11 but water W accumulates in the underground pipe 11, the water W in the underground pipe 11 may be discharged from the second end 11b of the underground pipe 11 by the air blown from the blower 20. The discharged water W accumulates in the second underground buried box 10b. When wind comes out from the second end 11b of the underground pipe 11, it is determined that no blockage occurs in the underground pipe 11, and coating formation is started. On the other hand, when a blockage occurs in the underground pipe 11, wind does not come out from the second end 11b of the underground pipe 11. When wind does not come out from the second end 11b of the underground pipe 11, the blockage in the underground pipe 11 is removed. Then, after it is confirmed that air is coming out of the second end 11b of the underground buried pipe 11, the film formation is started.

[0025] The coating forming method includes a kneading step, an adhesion step, and a drying step. The kneading step is a step of preparing the film-forming agent 14 containing a resin dispersion liquid in which a water-insoluble resin is dispersed. In the kneading step of this embodiment, the film-forming agent 14 is prepared by kneading the water-insoluble microcapsules in which the small animal control component is encapsulated and the resin dispersion liquid in which the water-insoluble resin is dispersed. That is, the film-forming agent 14 of this embodiment contains the water-insoluble microcapsules in which the small animal control component is encapsulated and the resin dispersion liquid in which the water-insoluble resin is dispersed. In this embodiment, since termite control is assumed, the small animal control component is a neonicotinoid compound. The resin dispersion liquid of this embodiment is a polyurethane emulsion made of ether-based polyurethane and water. In this embodiment, the resin content in the resin dispersion liquid is 1%. The viscosity of the resin dispersion liquid of this embodiment is 20 mPa·s. The film-forming temperature of the resin dispersion liquid of this embodiment is 0 degrees or higher.

[0026] The adhering step is a step of adhering the coating agent 14 to the inner surface 11 c of the underground buried pipe 11 and the outer surface 12 a of the wiring 12 . As shown in FIG. 3, the adhering step of this embodiment includes a filling step of filling an underground buried pipe 11 with a coating agent 14.

[0027] Before starting to fill the underground pipe 11 with the coating agent 14, cement 21 is filled as a temporary blocking member between the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 at the first end 11a and the second end 11b of the underground pipe 11. As a result, both ends of the underground pipe 11 are blocked.

[0028] A first air vent pipe 22 and an injection pipe 23 are inserted into the cement 21 filled in the first end 11a of the underground pipe 11. A first air vent valve 22a is provided on the end of the first air vent pipe 22 that protrudes into the first underground box 10a. When the first air vent valve 22a is open, the underground pipe 11 communicates with the first underground box 10a. A first opening / closing valve 23a is provided on the end of the injection pipe 23 that protrudes into the first underground box 10a. A container 24 is prepared on the ground G in which the coating agent 14 is stored. A submersible pump 25 is provided in the container 24. The submersible pump 25 and the injection pipe 23 are connected by a hose 26. When the first on-off valve 23a is in an open state, the coating agent 14 in the container 24 is sent by the submersible pump 25 through the hose 26 into the underground pipe 11. When the first on-off valve 23a is in a closed state, the coating agent 14 is not sent into the underground pipe 11.

[0029] A second air vent pipe 27 and a discharge pipe 28 are inserted into the cement 21 filled in the second end 11b of the underground pipe 11. A second air vent valve 27a is provided on the end of the second air vent pipe 27 that protrudes into the second underground buried box 10b. When the second air vent valve 27a is open, the inside of the underground pipe 11 communicates with the inside of the second underground buried box 10b. A second opening / closing valve 28a is provided on the end of the discharge pipe 28 that protrudes into the second underground buried box 10b.

[0030] In the filling step, the first opening / closing valve 23a, the first air vent valve 22a, and the second air vent valve 27a are opened, and the second opening / closing valve 28a is closed. Then, the underwater pump 25 is operated to fill the film forming agent 14 in the container 24 into the underground pipe 11. As a result, the film forming agent 14 is sequentially filled into the space partitioned by the inner surface 11c of the underground pipe 11 and the cement 21. That is, the film forming agent 14 is filled between the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. Then, when the space partitioned by the inner surface 11c of the underground pipe 11 and the cement 21 is filled with the film forming agent 14, the film forming agent 14 is sprayed from the second air vent pipe 27. When the coating agent 14 is sprayed out from the second air vent pipe 27, it is determined that the filling of the underground buried pipe 11 with the coating agent 14 is complete, and the first opening / closing valve 23a is closed.

[0031] 4, the attachment step of this embodiment includes a discharge step of discharging the coating forming agent 14 filled in the filling step from the underground pipe 11. Before starting to discharge the coating forming agent 14 from the underground pipe 11, a container 24 is placed in the second underground buried box 10b, and a submersible pump 25 is provided in the container 24. In addition, a recovery bottle 29 is provided on the ground G. The submersible pump 25 and the recovery bottle 29 are connected by a hose 26.

[0032] In the discharge step, the first opening / closing valve 23a, the first air vent valve 22a, and the second air vent valve 27a are closed, and the second opening / closing valve 28a is opened. Then, the coating agent 14 filled in the space partitioned by the inner surface 11c of the underground buried pipe 11 and the cement 21 is discharged through the discharge pipe 28. That is, the coating agent 14 is discharged from between the inner surface 11c of the underground buried pipe 11 and the outer surface 12a of the wiring 12. Then, the coating agent 14 discharged from the discharge pipe 28 is accumulated in the container 24. The coating agent 14 accumulated in the container 24 is collected by the underwater pump 25 through the hose 26 into the collection bottle 29.

[0033] Fig. 5(a) shows the underground pipe 11 and the wiring 12 after the discharging step. As shown in Fig. 5(b), the coating agent 14 is attached to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 after the discharging step. More specifically, the coating agent 14 is present between the lower portion of the inner surface 11c of the underground pipe 11 in the direction of gravity and the lower portion of the outer surface 12a of the wiring 12 in the direction of gravity. In addition, although the coating agent 14 is attached to the upper portion of the inner surface 11c of the underground pipe 11 in the direction of gravity and the upper portion of the outer surface 12a of the wiring 12 in the direction of gravity, they are separated from each other.

[0034] As shown in FIG. 6(a), the drying step is a step of drying the coating agent 14 attached to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. Specifically, after removing the cement 21 filled in the first end 11a and the second end 11b of the underground pipe 11, a blower 20 is inserted into the first end 11a of the underground pipe 11 and air is blown from the blower 20. As a result, air is blown from the first end 11a to the second end 11b inside the underground pipe 11. The coating agent 14 is dried by the air blown from the blower 20. More specifically, the resin contained in the coating agent 14 is hardened.

[0035] 6(b), by drying the coating agent 14 in the drying step, a coating 13 containing microcapsules encapsulating small animal control ingredients and a water-insoluble resin is formed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. In addition, the lower portion of the inner surface 11c of the underground pipe 11 in the direction of gravity and the lower portion of the outer surface 12a of the wiring 12 in the direction of gravity are bonded together by the hardened resin.

[0036] The operation and effects of this embodiment will be described. (1) The coating agent 14 applied to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 is dried, whereby the resin contained in the coating agent 14 is hardened. As a result, the coating 13 is formed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12.

[0037] The inner surface 11c of the underground buried pipe 11 and the outer surface 12a of the wiring 12 are bonded with the hardened resin, thereby restricting the movement of the wiring 12. This makes it possible to suppress the occurrence of the surfing phenomenon of the wiring 12.

[0038] The coating agent 14 uses a resin dispersion capable of forming a resin coating having an adhesive strength that allows the underground buried pipe 11 and the wiring 12 to be peeled off at 2 N / cm or less. Therefore, the part that bonds the inner surface 11c of the underground buried pipe 11 and the outer surface 12a of the wiring 12 also has an adhesive strength that allows the wiring 12 to be peeled off at 2 N / cm or less. This allows the wiring 12 to be peeled off from the underground buried pipe 11 simply by towing the wiring 12 with a towing machine 8t that is generally used in the construction of underground electric power lines. This makes it easier to pull out the wiring 12 from the underground buried pipe 11.

[0039] (2) In this embodiment, the film-forming agent 14 is filled in the underground pipe 11, and then the filled film-forming agent 14 is discharged from the underground pipe 11, thereby attaching the film-forming agent 14 to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. Therefore, compared to the case where the film-forming agent 14 is sprayed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 by a sprayer, for example, the film-forming agent 14 can be easily attached to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. In particular, when an underground electric line has already been formed, it is difficult to insert a sprayer into the underground pipe 11 that is tens to hundreds of meters long, and therefore the method of this embodiment is effective.

[0040] Furthermore, since the application of the coating film forming agent 14 to the underground buried pipe 11 and the application of the coating film forming agent 14 to the wiring 12 can be performed simultaneously, the coating film 13 can be formed efficiently. Furthermore, when forming an underground electric wire after applying the coating film forming agent 14 to the underground pipe 11 and the wiring 12, it is necessary to carefully insert the wiring 12 into the underground pipe 11 so that the coating film forming agent 14 formed on the outer surface 12a of the wiring 12 does not fall off. In contrast, in this embodiment, since the coating film forming agent 14 is applied after the underground electric wire is formed, there is no need to worry about the coating film forming agent 14 falling off from the outer surface 12a of the wiring 12.

[0041] (3) The viscosity of the resin dispersion contained in the coating agent 14 is 20 mPa·s. Therefore, the coating agent 14 can be pumped into the underground pipe 11 by the submersible pump 25.

[0042] (4) The coating agent 14 contains microcapsules in which small animal control components are encapsulated. Therefore, the coating 13 formed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 also contains microcapsules in which small animal control components are encapsulated. This enables small animal control of the underground pipe 11 and the wiring 12. In addition, the resin hardens to prevent the small animal control components from leaking out, so the small animal control effect can be maintained.

[0043] (5) When the resin dispersion alone is applied to the outer surface 12a of the wiring 12, the resin dispersion drips from the wiring 12 because the resin dispersion is water-repellent to the outer surface 12a of the wiring 12. In contrast, in this embodiment, the resin dispersion is mixed with microcapsules in the form of fine particles of 1 to 10 μm and applied to the outer surface 12a of the wiring 12. In this case, the microcapsules are attached to the outer surface 12a of the wiring 12, so that the resin dispersion can be prevented from dripping from the wiring 12.

[0044] (6) When the wiring 12 is a power transmission cable, the heat resistance temperature of the wiring 12 is set on the assumption that the temperature will rise to around 60 degrees. In addition, water may enter the underground buried pipe 11. For this reason, if an ester-based polyurethane that starts hydrolysis at 65 degrees or higher is used as the water-insoluble resin, there is a possibility that it will hydrolyze. The amine generated by hydrolysis may damage the sheath of the wiring 12. In contrast, ether-based polyurethane has a hydrolysis start temperature of about 150 degrees and is water resistant. In this embodiment, since an ether-based polyurethane is used as the water-insoluble resin, damage to the sheath of the wiring 12 due to hydrolysis can be suppressed.

[0045] (7) In the prior art, for example, when an inspection device needs to be inserted between the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 in the inspection of the underground pipe 11 or the wiring 12, the water-absorbent polymer or the soft polyvinyl chloride material must be removed. In contrast, in the present embodiment, the upper part of the inner surface 11c of the underground pipe 11 in the direction of gravity is separated from the upper part of the outer surface 12a of the wiring 12 in the direction of gravity. Therefore, during the inspection, the inspection device can be inserted between the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 without removing the water-absorbent polymer or the soft polyvinyl chloride material. Therefore, the inspection can be performed smoothly.

[0046] (8) The cost can be reduced compared to the case where the wiring 12 is protected against termites by an anti-termite cable covered with an anti-termite layer made of nylon. (9) In the drying process of this embodiment, the coating film forming agent 14 is dried by air blown from the blower 20. Therefore, the coating film 13 can be formed more quickly compared to the case where the coating film forming agent 14 is dried by natural drying.

[0047] This embodiment can be modified as follows: The embodiment and the modified examples can be combined with each other to the extent that there is no technical contradiction. A piping material serving as wiring and piping material may be inserted into the underground buried pipe 11.

[0048] The wiring 12 may be a communication cable such as an optical fiber cable. When the only objective is to suppress the surfing phenomenon of the wiring 12, the coating agent 14 does not need to contain microcapsules containing small animal control ingredients. In this case, the coating 13 will be a simple resin coating rather than a small animal control coating.

[0049] In this case, the coating 13 may be formed on the lower portion of the inner surface 11c of the underground pipe 11 in the direction of gravity and on the lower portion of the outer surface 12a of the wiring 12 in the direction of gravity so that the underground pipe 11 and the wiring 12 are bonded by the resin. In other words, the coating 13 may not be formed on the entire inner surface 11c of the underground pipe 11 and the entire outer surface 12a of the wiring 12. Therefore, in the filling step, the coating forming agent 14 may be filled into the underground pipe 11 up to a water level at which the lower portion of the inner surface 11c of the underground pipe 11 in the direction of gravity and the lower portion of the outer surface 12a of the wiring 12 in the direction of gravity are immersed in the coating forming agent 14.

[0050] In this way, when it is not necessary to fill the underground pipe 11 to the full with the coating agent 14, the maintenance process can be omitted. For example, if the coating agent 14 does not flow out from the second end 11b when the coating agent 14 is filled from the first end 11a of the underground pipe 11, it is determined that a blockage has occurred in the underground pipe 11, and the coating agent 14 is then filled from the second end 11b as well. In addition, the amount of coating agent 14 used can be reduced.

[0051] In the above embodiment, termites are assumed to be small animals that cause damage to the underground pipes 11 and the wiring 12. However, small animals such as cockroaches and mice may also cause damage to the underground pipes 11 and the wiring 12. In other words, small animal control is not limited to termite control, but also includes cockroach control and mouse control.

[0052] The small animal control ingredient for termite control is not limited to a neonicotinoid compound, but may be a pyrethroid. The small animal control ingredient may be changed depending on the small animal to be controlled. For example, capsaicin may be used as the small animal control ingredient for rat control.

[0053] The water-insoluble resin is not limited to polyurethane, but may be acrylic, epoxy, or silicone. Since acrylic, epoxy, and silicone are water-resistant, the small animal control effect of the coating 13 is likely to be maintained even if water flows into the underground buried pipe 11.

[0054] The viscosity of the resin dispersion may be changed as appropriate. However, the higher the viscosity of the resin dispersion, the greater the amount of the film-forming agent 14 adhering to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12, i.e., the greater the amount of resin adhering to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. Therefore, the higher the viscosity of the resin dispersion, the greater the adhesive strength between the underground pipe 11 and the wiring 12. On the other hand, the lower the viscosity of the resin dispersion, the smaller the amount of the film-forming agent 14 adhering to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. For example, if the viscosity of the resin dispersion is lower than 10 mPa·s, the film-forming agent 14 will flow down from the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12, and the microcapsules will not be retained on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. Therefore, the viscosity of the resin dispersion is set so that a resin coating is formed that can retain the microcapsules on the underground pipe 11 and the wiring 12 and has an adhesive strength that allows the adhesion between the underground pipe 11 and the wiring 12 to be peeled off at a tensile speed of 2 N / cm or less.

[0055] Furthermore, if the viscosity of the resin dispersion is 400 mPa·s or less, the coating agent 14 can be sent into the underground pipe 11 using a submersible pump 25, or the coating agent 14 can be sprayed onto the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 using a high-pressure sprayer.

[0056] In addition to the resin dispersion, the coating agent 14 may contain, for example, a thickener for increasing the viscosity of the coating agent 14 . The resin content in the resin dispersion may be changed as appropriate. However, if the resin content in the resin dispersion is less than 1%, there is a risk that the coating agent 14 will not adhere to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. Also, the higher the resin content in the resin dispersion, the higher the adhesive strength between the underground pipe 11 and the wiring 12. For this reason, the resin content in the resin dispersion is set so that a resin coating having an adhesive strength of 2 N / cm or less that allows the adhesion between the underground pipe 11 and the wiring 12 to be peeled off is formed.

[0057] In the above embodiment, the underground pipe 11 is made of concrete and the sheath of the wiring 12 is made of polyvinyl chloride, but the material of the underground pipe 11 and the material of the sheath of the wiring 12 may be changed as appropriate. The resin content, etc. in the resin dispersion is set according to the material of the underground pipe 11 and the material of the wiring 12 so that a resin coating having an adhesive strength of 2 N / cm or less that allows the adhesion between the underground pipe 11 and the wiring 12 to be peeled off is formed.

[0058] In the maintenance process, the method of checking for the presence or absence of a clog in the underground pipe 11 may be changed as appropriate. For example, the presence or absence of a clog in the underground pipe 11 may be checked by flowing water into the underground pipe 11. In this case, if there is a clog in the underground pipe 11, the clog may be washed away by the water, and the clog in the underground pipe 11 may be removed. Also, the presence or absence of a clog in the underground pipe 11 may be checked by inserting a camera into the underground pipe 11.

[0059] The kneading step may be carried out before the conditioning step or simultaneously with the conditioning step. The coating film forming method may further include a foaming step of foaming the liquid coating film forming agent 14 to form a foamed coating film forming agent 14. The foaming step may be performed after the kneading step or simultaneously with the kneading step.

[0060] In this case, in the adhesion step, the foamed film-forming agent 14 is filled into the underground pipe 11. The foamed film-forming agent 14 defoams inside the underground pipe 11, and adheres to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12. By using the foamed film-forming agent 14, the amount of the film-forming agent 14 used can be reduced compared to when a liquid film-forming agent 14 is used.

[0061] The coating agent 14 may be filled in the underground pipe 11 in a liquid state and then allowed to foam naturally within the underground pipe 11 . In the adhering step, the method of adhering the coating agent 14 to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 may be changed as appropriate. For example, the coating agent 14 may be adhered to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 by spraying the coating agent 14 with a high-pressure sprayer.

[0062] In the filling step, the coating agent 14 may be filled into the underground pipe 11 from both ends of the underground pipe 11 . The coating agent 14 uses a resin dispersion liquid with a film-forming temperature of 0° C. or higher. Therefore, the method of drying the coating agent 14 in the drying step is not limited to blowing air with the blower 20, and natural drying may also be used. [Explanation of symbols]

[0063] 11...underground buried pipe, 11c...inner surface, 12...wiring as wiring / piping material, 12a...outer surface, 13...coating, 14...coating forming agent.

Claims

1. A method for forming a coating on an underground buried pipe buried in the ground and a wiring / piping material inserted into the underground buried pipe and disposed within the underground buried pipe so as to abut against an inner surface of the underground buried pipe, comprising the steps of: a coating process for coating an inner surface of the underground buried pipe and an outer surface of the wiring / piping material with a coating agent containing a resin dispersion liquid in which a water-insoluble resin is dispersed; a drying step of drying the coating agent adhered to the inner surface of the underground buried pipe and the outer surface of the wiring / piping material; Including, The coating method is characterized in that the resin dispersion is capable of forming a resin coating having a film-forming temperature of 0 degrees or higher and an adhesive strength of 2 N / cm or less that allows the adhesion between the underground buried pipe and the wiring / piping material to be peeled off.

2. The attachment step includes: a filling step of filling the film-forming agent between the inner surface of the underground buried pipe and the outer surface of the wiring / piping material; a discharge step of discharging the coating agent filled in the filling step from between the inner surface of the underground buried pipe and the outer surface of the wiring / piping material; The method for forming a coating according to claim 1, comprising the steps of:

3. 3. The method for forming a coating according to claim 1, wherein the coating agent is in a foam form and is applied to the inner surface of the underground buried pipe and to the outer surface of the wiring / piping material in the application step.

4. The coating method according to any one of claims 1 to 3, wherein the coating agent is applied to the substrate, the coating agent comprising a water-insoluble microcapsule containing a small animal control component and the resin dispersion in the adhesion step.

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