Film formation agent

Abstract

To provide a film formation agent which can suppress a surfing phenomenon of a wiring / piping material, and facilitates preparation work when the wiring / piping material is pulled out from an underground buried pipe.SOLUTION: A film formation agent 14 for an underground buried pipe 11 buried in the underground UG and wiring 12 inserted into the underground buried pipe 11 is composed of resin dissolution liquid in which a water-soluble resin is dissolved in an aqueous solution, and is attached to the inner surface 11c of the underground buried pipe 11 and the outer surface 12a of the wiring 12.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a coating agent for underground pipes and wiring / piping materials inserted into underground pipes. [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 boxes. 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, a preparatory work is required to remove the water-absorbent polymer or soft polyvinyl chloride resin material filled between the underground pipe and the wiring and piping materials before pulling them out 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 as a preparatory work has been an impediment to the progress of construction work. [Means for solving the problem]

[0007] 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, and is composed of a resin solution in which a water-soluble resin is dissolved in an aqueous solution, and is attached to the inner surface of the underground pipes and the outer surface of the wiring and piping materials.

[0008] Regarding the coating agent, the resin solution may contain 8% by mass or less of the water-soluble resin having a saponification degree of 86.5 to 89.0% and a polymerization degree of 300 to 400. Regarding the coating agent, the viscosity of the resin solution at 25 degrees may be 8 mPa·s or more and 400 mPa·s or less.

[0009] The film-forming agent may also include water-insoluble microcapsules in which the small animal control component is encapsulated. 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, and is a solid made of a water-soluble resin that is dissolved in water and attached to the inner surface of the underground pipes and the outer surface of the wiring and piping materials.

[0010] Regarding the film-forming agent, the water-soluble resin may be in the form of a film. Regarding the film-forming agent, the water-soluble resin may contain water-insoluble microcapsules in which a small animal control component is encapsulated. Effect of the Invention

[0011] According to the present invention, the surfing phenomenon of wiring and piping materials can be suppressed, and preparation work for pulling out wiring and piping materials from underground buried pipes can be facilitated. [Brief description of the drawings]

[0012] [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 coating agent 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

[0013] A first embodiment of the coating film forming method and coating film forming agent will be described below with reference to Figs. (First embodiment) <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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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-soluble resin. The water-soluble resin in this embodiment is PVA: polyvinyl alcohol. 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.

[0018] The underground pipe 11 and the wiring 12 are bonded together by a coating 13. More specifically, a lower portion of the inner surface 11c of the underground pipe 11 in the direction of gravity and a lower portion of the outer surface 12a of the wiring 12 in the direction of gravity are bonded together by a resin contained in the coating 13.

[0019] <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.

[0020] 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.

[0021] 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.

[0022] The coating forming method includes a kneading step, an adhesion step, and a drying step. The kneading step is a step of preparing a liquid film-forming agent 14 by dissolving a water-soluble resin in an aqueous solution. In the kneading step of this embodiment, a water-insoluble microcapsule in which a small animal control component is encapsulated and a resin solution in which a water-soluble resin is dissolved in an aqueous solution are kneaded to prepare a liquid film-forming agent 14. That is, the film-forming agent 14 of this embodiment includes a water-insoluble microcapsule in which a small animal control component is encapsulated and a water-soluble resin. In this embodiment, since termite control is assumed, the small animal control component is a neonicotinoid compound. The water-soluble resin of this embodiment is PVA: polyvinyl alcohol. The resin solution of this embodiment contains 8 mass % or less of a water-soluble resin having a saponification degree of 86.5 to 89.0% and a polymerization degree of 300 to 400. The viscosity of the resin solution of this embodiment is 20 mPa·s at 25 degrees.

[0023] The adhering step is a step of adhering a liquid coating-forming 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 film-forming agent filling step of filling the underground buried pipe 11 with a film-forming agent 14 .

[0024] 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.

[0025] 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.

[0026] 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.

[0027] In the coating agent 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. Next, the underwater pump 25 is operated to fill the coating agent 14 in the container 24 into the underground pipe 11. As a result, the coating agent 14 is filled sequentially into the space partitioned by the inner surface 11c of the underground pipe 11 and the cement 21. That is, the coating 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 coating agent 14, the coating 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.

[0028] 4, the attachment step of this embodiment includes a film-forming agent discharging step as a discharging step for discharging the film-forming agent 14 filled in the filling step from the underground buried pipe 11. Before starting to discharge the film-forming agent 14 from the underground buried 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.

[0029] In the coating agent 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.

[0030] 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.

[0031] 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.

[0032] 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-soluble 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.

[0033] Incidentally, in repair work for an underground electric cable, the wiring 12 may be pulled out from the underground pipe 11. A towing machine 8t is generally used to pull out the wiring 12 from the underground pipe 11. If the adhesive strength between the underground pipe 11 and the wiring 12 is high, the wiring 12 will not peel off from the underground pipe 11 even if the wiring 12 is pulled by the towing machine 8t, and the wiring 12 cannot be pulled out from the underground pipe 11. Therefore, as a preparatory work for pulling out the wiring 12 from the underground pipe 11, it is necessary to weaken the adhesive strength between the underground pipe 11 and the wiring 12.

[0034] Since the resin contained in the coating 13 is water-soluble, the coating 13 dissolves in water. Therefore, when water is run through the underground pipe 11, at least a part of the coating 13 formed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 dissolves in the water. As a result, the adhesive strength between the underground pipe 11 and the wiring 12 is weakened, and the wiring 12 becomes easily peeled off from the underground pipe 11.

[0035] Here, an example of a procedure for dissolving the coating 13 in water will be described. First, water is filled into the underground pipe 11. The method for filling the underground pipe 11 with water is the same as the method for filling the underground pipe 11 with the coating forming agent 14 in the above-mentioned coating forming agent filling step, and therefore a description thereof will be omitted. At least a part of the coating 13 formed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 dissolves in the water filled into the underground pipe 11.

[0036] Next, the water in the underground pipe 11 is discharged. The method for discharging the water from the underground pipe 11 is the same as the method for discharging the coating agent 14 from the underground pipe 11 in the above-mentioned coating agent discharging step, and therefore the explanation will be omitted. The water in which the coating agent 14 is dissolved is discharged from the underground pipe 11.

[0037] In this manner, by dissolving at least a portion of the coating 13 formed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 in water, the adhesive strength between the underground pipe 11 and the wiring 12 can be weakened.

[0038] In this embodiment, before the underground pipe 11 is filled with water, the underground pipe 11 and the wiring 12 are bonded with an adhesive strength of about 5.88 to 7.84 N / cm, which allows the underground pipe 11 and the wiring 12 to be peeled off. The resin dissolving solution of this embodiment contains 8 mass % or less of a water-soluble resin with a saponification degree of 86.5 to 89.0% and a polymerization degree of 300 to 400. Therefore, when the underground pipe 11 is filled with water, the coating 13 dissolves in water in about 1 to 3 hours. After at least a part of the coating 13 dissolves in water, the adhesive strength between the underground pipe 11 and the wiring 12 decreases to an adhesive strength of 2 N / cm or less, which allows the underground pipe 11 and the wiring 12 to be peeled off. 2N / cm is the upper limit of the adhesive strength that can be pulled out by the towing machine 8t when it is assumed that the wiring 12 of the maximum diameter generally used is wired over a maximum distance of 200m 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 due to repeated collection of the wiring 12, and the underground buried pipe 11 may be damaged if the adhesive strength is too high. Therefore, the wiring 12 can be peeled off from the underground buried pipe 11 simply by pulling the wiring 12 with the towing machine 8t.

[0039] The operation and effects of the first embodiment will be described. (1-1) 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.

[0040] 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.

[0041] On the other hand, since the underground pipe 11 and the wiring 12 are bonded by resin, when the wiring 12 is pulled out from the underground pipe 11, it is necessary to peel off the wiring 12 from the underground pipe 11. Since the resin contained in the coating agent 14 is water-soluble, the coating 13 dissolves in water. Therefore, when water is poured into the underground pipe 11, at least a part of the coating 13 formed on the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 dissolves in water. As a result, the adhesive strength between the underground pipe 11 and the wiring 12 is weakened, so that the wiring 12 can be easily peeled off from the underground pipe 11. In other words, the preparation work for pulling out the wiring 12 from the underground pipe 11 is only required to pour water into the underground pipe 11. Therefore, the preparation work is easier than that in the prior art, in which the water-absorbent polymer or soft polyvinyl chloride material is removed over a length of several tens to several hundreds of meters as preparation work for pulling out the wiring 12 from the underground buried pipe 11.

[0042] (1-2) 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 with 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.

[0043] 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.

[0044] (1-3) The resin dissolving solution of the present embodiment contains 8 mass % or less of a water-soluble resin having a saponification degree of 86.5 to 89.0% and a polymerization degree of 300 to 400, so that the coating 13 dissolves in water in about 1 to 3 hours. This allows smooth preparation work for pulling out the wiring 12 from the underground buried pipe 11.

[0045] (1-4) The viscosity of the resin solution contained in the coating agent 14 is 20 mPa·s at 25 degrees. Therefore, the coating agent 14 can be pumped into the underground buried pipe 11 by the submersible pump 25.

[0046] (1-5) 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 that the small animal control effect can be maintained.

[0047] (1-6) 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.

[0048] (1-7) 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. (1-8) In the drying step 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.

[0049] Second embodiment A second embodiment that embodies the coating method and coating agent will be described below. Note that, regarding the coating method, only the differences from the first embodiment will be described.

[0050] In the first embodiment, a liquid film-forming agent 14 made of a resin solution in which a water-soluble resin is dissolved in an aqueous solution is used, whereas in the second embodiment, a solid film-forming agent 14 is used.

[0051] The film-forming agent 14 of the second embodiment is made of a water-soluble resin. The water-soluble resin of this embodiment is PVA: polyvinyl alcohol. The water-soluble resin of this embodiment is in the form of a film. The water-soluble resin of this embodiment includes water-insoluble microcapsules in which a small animal control component is encapsulated. The small animal control component of this embodiment is a neonicotinoid compound.

[0052] Since the solid film-forming agent 14 cannot be attached to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12, in the kneading step of the second embodiment, the solid film-forming agent 14 is kneaded with water to create a liquid film-forming agent 14. As a result, in the attachment step, the solid film-forming agent 14 is attached to the inner surface 11c of the underground pipe 11 and the outer surface 12a of the wiring 12 in a state dissolved in water.

[0053] The effects of the second embodiment will be described below. In the second embodiment, in addition to the effects (1-1), (1-2), and (1-5) to (1-8) of the first embodiment, the following effects can be obtained.

[0054] (2-1) The coating agent 14 of this embodiment is a solid, and is dissolved in water before being applied to the inner surface 11c of the underground buried pipe 11 and the outer surface 12a of the wiring 12. Therefore, it is easier to carry than the coating agent 14 made of a resin solution as in the first embodiment. Also, the storage space for the coating agent 14 can be reduced.

[0055] (2-2) The water-soluble resin of the present embodiment is in the form of a film, and therefore is more easily dissolved in water than, for example, a water-soluble resin in the form of a block. The above embodiment may be modified as follows: The above embodiment and modifications may be combined with each other to the extent that no technical contradiction occurs.

[0056] A piping material serving as wiring and piping material may be inserted into the underground buried pipe 11. 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The water-soluble resin is not limited to PVA (polyvinyl alcohol) and may be changed as appropriate. The viscosity of the resin solution may be changed as appropriate. However, the higher the viscosity of the resin solution, 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 solution, 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 solution, 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 solution is lower than 8 mPa·s at 25 degrees, the film-forming agent 14 will flow off 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.

[0062] Furthermore, if the viscosity of the resin solution is 400 mPa·s or less at 25 degrees, the coating agent 14 can be sent into the underground pipe 11 using an underwater 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.

[0063] The film-forming agent 14 may be a resin solution containing a high proportion of water-soluble resin, i.e., a high-concentration resin solution, which is diluted with water to reduce the concentration. In the above embodiment, the underground pipe 11 is made of concrete and the sheath of the wiring 12 is made of polyvinyl chloride. However, the materials of the underground pipe 11 and the sheath of the wiring 12 may be changed as appropriate.

[0064] 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.

[0065] The kneading step may be carried out before the conditioning step or simultaneously with the conditioning step. 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.

[0066] 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 technical ideas that can be understood from the above-described embodiment and modified examples will be described.

[0067] <Appendix 1> A method for forming a coating on an underground pipe buried in the ground and wiring / piping material inserted into the underground pipe, comprising the steps of: a coating process for coating a liquid coating agent, which is a water-soluble resin dissolved in an aqueous solution, on the inner surface of the underground buried pipe and the outer surface of the wiring / piping material; 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.

[0068] <Appendix 2> The attachment step includes: 2. The coating method according to claim 1, further comprising: a filling step of filling the gap between the inner surface of the underground pipe and the outer surface of the wiring / piping material with the coating agent; and a discharging step of discharging the coating agent filled in the filling step from the gap between the inner surface of the underground pipe and the outer surface of the wiring / piping material.

[0069] <Appendix 3> The coating method according to claim 1 or 2, wherein the coating step comprises coating the coating-forming agent containing water-insoluble microcapsules encapsulating a small animal control component and the water-soluble resin. [Explanation of symbols]

[0070] 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 coating agent for an underground buried pipe buried in the ground and for wiring / piping materials inserted into the underground buried pipe, comprising: It consists of a resin solution in which a water-soluble resin is dissolved in an aqueous solution, A coating agent which is applied to the inner surface of the underground buried pipe and the outer surface of the wiring / piping material.

2. 2. The coating agent according to claim 1, wherein the resin solution contains 8% by mass or less of the water-soluble resin having a saponification degree of 86.5 to 89.0% and a polymerization degree of 300 to 400.

3. 3. The coating agent according to claim 1, wherein the viscosity of the resin solution is 8 mPa·s or more and 400 mPa·s or less at 25 degrees.

4. The coating agent according to any one of claims 1 to 3, further comprising water-insoluble microcapsules in which a small animal control component is encapsulated.

5. A coating agent for an underground buried pipe buried in the ground and for wiring / piping materials inserted into the underground buried pipe, comprising: It is a solid material made of a water-soluble resin, A film-forming agent which is dissolved in water and applied to the inner surface of the underground buried pipe and the outer surface of the wiring / piping material.

6. The coating composition according to claim 5, wherein the water-soluble resin is in the form of a film.

7. 7. The film-forming agent according to claim 5, wherein the water-soluble resin contains water-insoluble microcapsules in which a small animal control component is encapsulated.

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