JP2013123799A - Resin coating film forming method, lid body for underground structure, and lid body-receiving frame for under ground structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin coating film forming method by which a resin coating film having a desired thickness is easily formed.SOLUTION: The resin coating film forming method by which the resin coating film 12 is formed on an iron lid body 11 using resin impregnated fibers 41 formed by impregnating the gap between the fibers with resin, includes: a preparation step of preparing an iron lid body 11' with fiber, which is provided with the resin impregnated fibers 41 between a resin film 42 and the iron lid body 11; an embedding step of embedding the iron lid body 11' with the fibers prepared in the preparation step into a granular material; a pressing step of pressing the resin impregnated fibers 41 to the iron lid body 11 side by pressurizing the granular material; and a curing step of curing the resin with which the resin impregnated fibers 41 provided to the iron lid body 11' with the fiber embedded in the granular material pressurized in the pressing step is impregnated.

Description

  The present invention relates to a resin film forming method for forming a resin film on a structure using a resin-impregnated fiber in which a resin is impregnated between fibers, a lid for an underground structure that closes an opening connected to the underground structure, and the same The present invention relates to a cover receiving frame for an underground structure that supports the cover.

  Covers for underground structures that close the openings that lead to underground and underground facilities or underground structures in sewers and waterworks, electric power, gas, communications, etc., and lids for underground structures that support the cover The structure may be provided with a resin coating on the surface for the purpose of improving waterproofness, corrosion resistance or strength. In addition, a resin film may be provided on the surface of the structure in order to repair a crack or the like generated in the structure. As a method for performing this repair, a film forming method for forming a resin film on the inner peripheral surface of a tubular structure has been proposed (for example, see Patent Document 1). In addition, techniques disclosed in Patent Document 2 and Patent Document 3 are generally known as techniques related to resin molding. Also known is a method of forming a resin film on the surface of a structure by a method such as brushing.

  For example, a structure such as a cover for an underground structure that closes an opening of the underground structure or a cover for an underground structure that supports the cover has a complicated shape having protrusions or recesses such as ribs. There is something. In recent years, there is a demand for forming a resin film having a desired thickness on such a complex-shaped structure.

JP 2011-140221 A JP 2002-254446 A JP 2001-260239 A

  However, the resin paint may hang down on the side portion of the protrusion or the recess until the applied resin paint is cured. When the resin coating hangs down, the resin coating film formed on the sagging portion tends to be thin, and the resin coating formed on the sagging tip portion tends to become thick. For this reason, there exists a problem that it is difficult to obtain a desired resin film especially in the structure of a complicated shape which has the side part of a protrusion part or a recessed part.

  In view of the above circumstances, the present invention provides a resin film forming method capable of easily forming a resin film having a desired thickness, a lid for an underground structure provided with a resin film having a desired thickness, and a desired thickness. It aims at providing the cover frame for underground structures provided with the resin film.

The resin film forming method of the present invention for solving the above-described object is a resin film forming method in which a resin film is formed on a structure using a resin-impregnated fiber in which a resin is impregnated between fibers.
A preparation step of preparing a fiber-attached structure including the resin-impregnated fibers between a resin film and the structure;
An burying step of burying the structure with fibers prepared in the preparation step in a granular material;
A pressing step of pressing the resin-impregnated fiber against the structure side by pressurizing the granular material;
And a curing step of curing the resin impregnated in the resin-impregnated fiber provided in the structure with fiber embedded in the granular material pressurized in the pressing step.

  According to the resin film forming method of the present invention, a resin coating having a desired thickness along the surface shape of the structure is obtained by pressing the resin-impregnated fiber against the structure by pressurizing the granular material. A film can be easily formed.

  In the resin film forming method of the present invention, the preparation step includes the step of preparing the structure having the resin-impregnated fibers between the resin films that are divided and arranged so that the respective end portions overlap. It is preferable that

  By using the resin film divided | segmented into plurality, each resin film can be easily made to follow the surface shape of a structure. In addition, since the resin films are arranged so that the respective end portions overlap each other, even when air enters between the structure and the resin-impregnated fiber, in the resin-impregnated fiber, or between the resin-impregnated fiber and the resin film. In the pressing step, the air is likely to be pushed out from the overlapping portion of the end portions of the resin film.

  Moreover, in the resin film formation method of this invention, it is preferable that the said preparatory process is a process of preparing the said structure which has the said sheet-like resin impregnated fiber cut | judged into plurality.

  Since the resin-impregnated fiber is divided into a plurality of parts, the resin-impregnated fiber is easily aligned with the surface shape of the structure.

The lid for an underground structure of the present invention that solves the above-mentioned object is a lid for an underground structure that closes an opening connected to the underground structure,
A metal lid body;
A lower surface resin coating provided on the lower surface of the lid body that becomes the underground side,
The lower surface resin coating is characterized in that at least a part thereof is formed by a sheet-like resin-impregnated fiber in which a resin is impregnated between fibers.

  According to the lid for an underground structure of the present invention, the resin is retained between the fibers even in a portion where it is difficult to form a thick film such as a side surface of the rib that causes liquid resin to flow down during molding. By using the sheet-shaped resin-impregnated fibers, a film having a desired thickness can be easily obtained.

The underground structure lid receiving frame of the present invention that solves the above-mentioned object is an underground structure lid receiving frame that supports an underground structure lid that closes an opening connected to the underground structure,
A metal receiving frame body formed in a cylindrical shape;
An inner peripheral resin film provided on the inner peripheral surface of the receiving frame body,
The inner peripheral resin coating is characterized in that at least a part thereof is formed by a sheet-like resin-impregnated fiber in which a resin is impregnated between fibers.

  According to the underground structure lid body receiving frame of the present invention, even if it is difficult to form a thick film such as an inner peripheral surface of the receiving frame body that causes liquid resin to flow down during molding, By using a sheet-like resin-impregnated fiber in which a resin is held, a film having a desired thickness can be easily obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the resin film formation method which can form the resin coating film of desired thickness easily, the cover for underground structures provided with the resin film of desired thickness, and the resin film of desired thickness The cover frame for underground structures provided with can be provided.

(A) is a cross-sectional view of a manhole iron cover corresponding to an embodiment of a cover for an underground structure of the present invention and a receiving frame corresponding to an embodiment of a cover receiving frame for an underground structure of the present invention; (B) is a top view of the manhole iron cover and receiving frame shown to the same figure (a). It is a figure which shows a mode that the manhole iron cover shown in FIG. 1 was rotated and the manhole iron cover was opened. It is a bottom view of the manhole iron cover shown to Fig.1 (a). It is BB sectional drawing of the manhole iron cover shown in FIG. It is a flowchart which shows the preparation method of a lower surface resin film. (A) is sectional drawing of rib vicinity which shows an example of the positional relationship of the resin impregnation fiber affixed in an affixing operation | work, and the film affixed in the covering operation | movement mentioned later, (b) is a modification of a film It is sectional drawing shown. It is an enlarged view which expands and shows the D section of Fig.2 (a). It is sectional drawing of a locking piece vicinity which shows an example of the positional relationship of the resin impregnating fiber for receiving frames stuck in a sticking operation | work, and the film for receiving frames stuck in a covering operation | work.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1A is a cross-sectional view of a manhole iron lid corresponding to one embodiment of a cover for an underground structure and a receiving frame corresponding to one embodiment of a cover receiving frame for an underground structure. ) Is a plan view of the manhole cover and the receiving frame shown in FIG. The cross-sectional view shown in FIG. 1A is a cross-sectional view taken along the line AA in FIG.

  FIG. 1 shows a manhole iron lid 1 and a receiving frame 5 formed in an annular shape to support the manhole iron lid 1. A sewer drain pipe, which is an underground buried object, is buried at a predetermined depth from the ground surface, and a manhole is provided as an underground facility in the middle of the sewer drain pipe. The manhole is formed as a vertical hole from the sewer drain pipe to the surface of the earth by using a box made of ready-made concrete moldings. The receiving frame 5 is provided on the housing and defines an opening H (see FIG. 2) connected to a manhole that is an underground structure. A sewer drain pipe and a manhole correspond to an example of a structure (more specifically, an underground structure). You may form the resin film mentioned later with respect to these structures.

  The manhole iron cover 1 has a circular shape in a top view so as to freely open and close the opening H connected to the manhole, and the manhole iron cover 1 shown in FIG. 1 closes the opening H. In FIG. 1A, the upper side of the figure is the ground side, and the lower side of the figure is the underground side (the sewer drain pipe side). A manhole iron lid 1 shown in FIG. 1 has an iron lid body 11 made of cast iron and a lower surface resin coating 12 formed by casting. The iron lid main body 11 may be made of iron other than cast iron or may be made of metal other than iron. The iron lid body 11 corresponds to an example of a lid body in the present invention, and also corresponds to an example of a structure.

  The iron lid main body 11 includes a disk part 111 and a rib 112 protruding downward from the disk part 111. The rib 112 is formed integrally with the disk portion 111 when the iron lid body 11 is cast for the purpose of increasing the strength of the manhole iron lid 1. The lower surface 30 of the iron lid body 11 is formed by a flat portion 31 on the surface of the disk portion 111 and a rib surface portion 32 on the surface of the rib 112. The lower surface resin film 12 is provided on the entire lower surface 30 of the iron lid body 11. In FIG. 1A, the lower surface resin film 12 is shown by a thick solid line. The lower surface resin film 12 will be described in detail later.

  The receiving frame 5 includes a receiving frame body 51 made of cast iron and an inner peripheral resin coating 52 formed by casting. The receiving frame main body 51 of the present embodiment also corresponds to an example of a structure in the present invention. The receiving frame main body 51 may be made of iron other than cast iron, or may be made of metal other than iron. The receiving frame main body 51 has a cylindrical shape formed in an annular shape in a top view having an inner peripheral surface 61. The receiving frame main body 51 is formed with a hinge seat 62 and a locking piece 63. The inner peripheral resin coating 52 is provided on the entire inner peripheral surface 61 of the receiving frame main body 51. In FIG. 1A, the inner peripheral resin film 52 is shown by a thick solid line. The inner peripheral resin film 52 will be described in detail later.

  As shown to Fig.1 (a), the hinge member 33 is connected with the one end side peripheral part in the lower surface 30 of the iron cover main body 11 so that rotation is possible. The hinge seat 62 formed in the receiving frame main body 51 is provided with a through hole 621 through which the hinge member 33 penetrates in the vertical direction. At the lower end of the hinge member 33 that has passed through the through hole 621 of the hinge seat 62, a protrusion 331 for preventing the protrusion is provided that protrudes in a direction perpendicular to the paper surface in FIG. On the other hand, a key hole 14 is provided on the peripheral edge of the other end side of the manhole cover 1. Further, a lock member 34 is provided on the other end side of the lower surface 30 so as to be rotatable about a rotation shaft 340. The lock member 34 includes a valve body 341 and a locking claw 342. The lock member 34 is biased by a spring 343 so that when the manhole iron cover 1 is lifted, the locking claw 342 is hooked on the locking piece 63 formed on the receiving frame main body 51. FIG. 1A shows the lock member 34 in the posture. In the posture of the lock member 34 shown in FIG. 1A, the valve body 341 enters the key hole 14 and closes the key hole 14.

  In order to open the manhole iron lid 1 with the opening closed as shown in FIG. 1, a rod-like opening / closing tool (not shown) is used. By inserting the tip of the opening / closing tool into the keyhole 14, the other end side of the manhole iron lid 1 can be lifted without the locking claw 342 being locked to the locking piece 63. The manhole iron cover 1 whose other end is lifted can be rotated together with the hinge member 33 with the hinge member 33 as a fulcrum. When the manhole iron cover 1 is opened and closed, the manhole iron cover 1 is turned in a substantially horizontal direction with the hinge member 33 as a fulcrum. During the turning, the lower surface 30 of the manhole iron cover 1 and the ground G (see FIG. 2) may be rubbed and the lower surface resin film 12 may be scraped off. By forming the lower surface resin coating 12 thick, it is possible to reduce the possibility that the entire lower surface resin coating 12 is scraped off.

  FIG. 2 is a view showing a state where the manhole iron cover shown in FIG. 1 is turned and the manhole iron cover is opened. Fig.2 (a) is sectional drawing which shows the mode, FIG.2 (b) is a top view of the manhole iron cover shown to the figure (a).

  In FIG. 2, the hinge member 33 and the lock member 34 are not shown. Moreover, the ground G is shown by Fig.2 (a). A manhole cover 1 shown in FIG. 2 is placed on the ground G. In the state before turning shown in FIG. 1, the manhole iron cover 1 can be lifted until the projection 331 (see FIG. 1A) of the hinge member 33 contacts the hinge seat 62 of the receiving frame main body 51. Further, when the manhole iron cover is turned approximately 90 degrees as shown in FIG. 2, the projection 331 of the hinge member 33 can pass through the through hole 621 of the hinge seat 62, and is lifted upward. The manhole iron cover 1 can be removed from the receiving frame 5.

  FIG. 3 is a bottom view of the manhole cover shown in FIG.

As shown in FIG. 3, the ribs 112 are arranged in a cross beam shape. An information display of the manhole iron lid 1 is cast out in a rectangular central region 300C surrounded by a part of the ribs 112 arranged in a cross pattern. That is, as shown in FIG. 3, “FCD 700” and “T-25 600” are represented in two stages. “FCD” is information representing the material of the manhole iron lid 1, “700” is information representing the tensile strength (N / mm ² ) of the manhole iron lid 1, and “T-25”. Is information representing the load resistance of the manhole iron cover 1, and "600" is information representing the diameter (nominal diameter) of the manhole iron cover 1. Such information can be said to be a kind of identification information for identifying the manhole iron cover 1. Note that the information displayed in the central area 300C is not limited to the information described here.

  4 is a BB cross-sectional view of the manhole iron cover shown in FIG. 3. In FIG. 4, the thickness of the lower surface resin coating 12 is exaggerated. In FIG. 4, only a part of the manhole cover is shown, but the lower surface resin film 12 is provided on the entire lower surface 30.

  As shown in FIG. 4, the lower surface resin coating 12 is composed of an electrodeposition coating 121 and a fiber-containing resin coating 123. The electrodeposition coating film 121 is a coating film formed by electrodeposition coating using a paint mainly composed of an epoxy resin. The film thickness of this electrodeposition coating film 121 is about 20 μm. In this embodiment, a general cationic electrodeposition coating is adopted as the electrodeposition coating, but anion electrodeposition coating may be adopted. By applying electrodeposition coating, an electrodeposition coating 121 that is firmly adhered to the cast skin of the iron lid body 11 and is difficult to peel is obtained. The electrodeposition coating 121 is formed not only on the lower surface 30 of the iron lid body 11 but also on the entire surface of the iron lid body 11 including the upper surface, but even if the electrodeposition coating 121 is formed only on the lower surface 30. Good. In FIG. 4, the thickness of the electrodeposition coating 121 applied to the upper surface of the iron lid body 11 is also exaggerated.

  The fiber-containing resin coating 123 is a coating that is in close contact with the electrodeposition coating 121. This fiber-containing resin coating 123 is formed by curing an epoxy resin of a resin-impregnated fiber 41 (see FIG. 6) in which a liquid epoxy resin is impregnated with a chopped strand mat that is a nonwoven fabric in which reinforcing fibers are arranged in random directions. It is the coating film formed by doing. The resin-impregnated fiber 41 is in a sheet shape cut into a plurality of pieces, and is arranged so that the respective end portions thereof are overlapped. For this reason, a thick portion 123 a is formed in the overlapping portion of the resin-impregnated fiber 41 in the fiber-containing resin coating film 123 formed by the resin-impregnated fiber 41. The fiber-containing resin coating film 123 is formed to have a thickness of about 1 mm except for the overlapping portion. The film thickness of the fiber-containing resin coating film 123 can be set to a desired thickness by adjusting the thickness of the resin-impregnated fiber 41.

  The resin impregnated in the resin-impregnated fiber 41 is mainly composed of an epoxy resin that is a thermosetting resin similar to the resin used in the electrodeposition coating film 121. By using the same resin as the main component, the fiber-containing resin coating 123 and the electrodeposition coating 121 are easily compatible, and the electrodeposition coating 121 and the fiber-containing resin coating 123 are in close contact with each other. . However, another coating film may be formed between the electrodeposition coating film 121 and the fiber-containing resin coating film 123. Further, as the resin impregnated in the resin-impregnated fiber 41, a thermosetting resin such as a urethane resin may be used in addition to the epoxy resin. Further, any fiber material other than the chopped strand mat may be used as long as the fiber material can impregnate a liquid resin between the fibers. In the present embodiment, glass fibers are used as the reinforcing fibers used for the resin-impregnated fibers 41, but other fibers such as chemical fibers and natural fibers other than glass fibers may be used.

  Then, the formation method of the lower surface resin film 12 is demonstrated.

  FIG. 5 is a flowchart showing a method of creating the bottom resin film.

  First, electrodeposition coating is performed on the entire surface of the iron lid body 11 including the lower surface 30 (step S1). Note that only the lower surface 30 may be electrodeposited. An electrodeposition coating 121 is formed by this electrodeposition coating. Next, a sticking operation for sticking the sheet-like resin-impregnated fiber 41 to the surface of the electrodeposition coating film 121 provided on the lower surface 30 is performed (step S2).

  FIG. 6A is a cross-sectional view in the vicinity of the ribs showing an example of the positional relationship between a resin-impregnated fiber to be attached in the attaching operation and a film to be attached in the covering operation described later. In FIG. 6A, the resin-impregnated fiber 41 is indicated by a thick solid line.

  The resin-impregnated fiber 41 includes a sheet-shaped flat portion resin-impregnated fiber 411 cut larger than the flat portion 31, and a sheet-shaped rib-shaped resin impregnated fiber 412 cut slightly smaller than the rib surface portion 32. Are divided in advance. In the pasting operation, the resin impregnated fiber 411 for the flat portion and the resin impregnated fiber 412 for the rib are pasted on the surface of the electrodeposition coating film 121 provided on the lower surface 30 of the iron lid body 11. In this pasting operation, first, the resin impregnated fiber 412 for ribs is pasted on the surface of the electrodeposition coating film 121 provided on the rib surface portion 32. That is, the rib resin-impregnated fiber 412 is affixed so as to cover the entire surface of the rib 112 excluding the root portion of the surface of the rib 112. Subsequently, the resin impregnated fiber 411 for the flat part is attached to the surface of the electrodeposition coating film 121 provided on the flat part 31. The edge part of the resin impregnated fiber 411 for flat part is affixed so that the standing part (root part) of the rib 112 may be covered. Since the resin impregnated fiber 411 for the flat portion and the resin impregnated fiber 412 for the rib are formed in a sheet shape, they can be easily attached along the shape of the lower surface 30.

  In a state where the resin-impregnated fiber 41 is attached to the surface of the electrodeposition coating 121 provided on the lower surface 30, the end portion of the flat portion resin-impregnated fiber 411 is overlapped with the end portion of the rib-impregnated resin impregnated fiber 412. Arranged. The fiber-containing resin coating 123 shown in FIG. 4 covers the entire lower surface 30 via the electrodeposition coating 121 by arranging the ends of the resin-impregnated fibers 411 for the flat portion and the resin-impregnated fibers 412 for the ribs so as to overlap each other. Can be reliably formed. Moreover, the adhesive strength of the resin impregnated fiber 411 for flat parts and the resin impregnated fiber 412 for ribs increases because edge parts have overlapped. Further, by using the resin-impregnated fiber 41 cut to a size that allows the end portions to overlap each other, the bottom surface can be moved even if the application positions of the flat-portion resin-impregnated fiber 411 and the rib-impregnated fiber-impregnated fiber 412 are slightly shifted. The entire 30 can be covered with the resin-impregnated fiber 41.

  In the pasting operation, the resin impregnated fiber 411 for the flat portion may be pasted first, and then the resin impregnated fiber 412 for the rib may be pasted. Further, the resin impregnated fiber 411 for the flat part cut slightly smaller than the flat part 31 and the resin impregnated fiber 412 for the rib cut larger than the rib surface part 32 are used, and the resin impregnated fiber 411 for the flat part is used. You may overlap the edge part of the resin impregnation fiber 412 for ribs to an edge part. Alternatively, a flat portion resin-impregnated fiber 411 cut to approximately the same size as the flat portion 31 and a rib resin-impregnated fiber 412 cut to approximately the same size as the rib surface portion 32 may be used. When using the rib-impregnated fiber impregnated fiber 412 cut to approximately the same size as the flat portion 31 and the rib surface portion 32, the end surfaces of the flat portion-impregnated fiber 411 and the rib-impregnated fiber 412 are attached to each other. That's fine. Further, for example, resin impregnated fibers 41 that are finely cut for each corner formed on the lower surface 30 such as a corner of the tip of the rib 112 or a corner of the base of the rib 112 may be used. In short, as long as the entire lower surface 30 of the iron lid body 11 provided with the electrodeposition coating film 121 can be covered, the resin-impregnated fiber 41 may be cut into an arbitrary size. Further, a single resin-impregnated fiber 41 that is not cut may be used. However, when one resin-impregnated fiber 41 is used, when the resin-impregnated fiber 41 is affixed to the surface of the electrodeposition coating 121 provided on the lower surface 30, the corner of the tip of the rib 112 or the root of the rib 112 is used. There is a problem that wrinkles are likely to occur in the resin-impregnated fiber 41 at the corners and the like. Further, when one resin-impregnated fiber 41 is used, there is a problem that it is difficult to match the resin-impregnated fiber 41 with the three-dimensional surface shape of the iron lid body 11. By using the resin-impregnated fibers 41 divided into a plurality, the resin-impregnated fibers 41 can be easily attached to the surface shape of the iron lid body 11 and attached. Moreover, by using the resin-impregnated fibers 41 divided into a plurality, it is possible to suppress the occurrence of wrinkles that are likely to occur when the resin-impregnated fibers 41 are attached to the surface of the electrodeposition coating 121 provided on the lower surface 30.

  Thereafter, a film obtained by cutting the surface of the resin-impregnated fiber 41 opposite to the surface of the resin-impregnated fiber 41 attached to the electrodeposition coating film 121 (hereinafter sometimes referred to as an anti-adhesion surface) into a plurality of pieces. The covering operation for covering with 42 is performed (step S3). By the electrodeposition coating, the pasting operation, and the covering operation described above, the fiber-covered iron lid body 11 ′ shown in FIG. 6A having the resin-impregnated fiber 41 between the film 42 and the iron lid body 11 is obtained. It is done. The fiber-attached iron lid body 11 ′ of this embodiment corresponds to an example of a fiber-attached structure in the present invention. In FIG. 6A, a gap is shown between the film 42 and the resin-impregnated fiber 41, and between the electrodeposition coating film 121 provided on the lower surface 30 and the resin-impregnated fiber 41. A fiber-attached iron lid body 11 'is formed by attaching the film 42 without a gap, the resin-impregnated fiber 41, and the electrodeposition coating 121 to each other. The film 42 is a polyethylene resin sheet having a thickness of 0.15 mm. The film 42 is divided into a flat part film 421 that has been cut in advance to be slightly larger than the flat part resin-impregnated fiber 411 and a rib film 422 that has been cut into approximately the same size as the rib resin-impregnated fiber 412. ing. In the covering operation, the flat part film 421 and the rib film 422 are attached to the non-sticking surface. In this covering operation, first, the flat portion film 421 is attached to the opposite side of the flat portion resin-impregnated fiber 411. Subsequently, a rib film 422 is attached to the opposite side of the rib resin-impregnated fiber 412. The film 42 can be attached to the resin-impregnated fiber 41 by the adhesive force of the epoxy resin impregnated in the resin-impregnated fiber 41. At the stage where the covering operation is completed, the opposite side of the resin-impregnated fiber 41 is covered with the film 42.

  As shown in FIG. 6A, the flat part film 421 is arranged so that the end part thereof overlaps with the end part of the rib film 422. By arranging the end portions of the flat portion film 421 and the rib film 422 so as to overlap each other, the entire anti-sticking surface of the resin-impregnated fiber 41 can be reliably covered with the film 42. In addition, by using the film 42 that is cut to a size that allows the end portions to overlap each other, the resin impregnated fibers 41 are not affected even if the positions where the flat portion film 421 and the rib film 422 are attached are slightly shifted. The entire pasting surface can be covered with the film 42.

  The covering operation may be performed by first attaching the rib film 422 to the opposite surface of the rib resin-impregnated fiber 412 and then attaching the flat portion film 421 to the opposite surface of the flat portion resin-impregnated fiber 411. Good. Moreover, as long as the edge part of the flat part film 421 and the edge part of the rib film 422 overlap, the flat part film 421 and the rib film 422 may be of any size. .

  FIG.6 (b) is sectional drawing which shows the modification of a film. In FIG.6 (b), the resin impregnation fiber 41 is shown by the thick continuous line.

  The film 42 of this modified example includes a flat part film 421 cut smaller than the flat part resin-impregnated fiber 411, a rib film 422 cut smaller than the rib resin-impregnated fiber 412, and a gap It is divided into a film 423. The gap film 423 is disposed between the flat portion film 421 and the rib film 422. Further, the end portions of the flat portion film 421 and the rib film 422 are arranged so as to overlap the end portion of the gap film 423. Further, for example, a film 42 that is finely cut for each corner formed on the lower surface 30 such as a corner at the tip of the rib 112 or a corner at the base of the rib 112 may be used. In short, as long as the entire surface of the resin-impregnated fiber 41 can be covered, the film 42 may be cut into an arbitrary size. Further, a single film 42 that is not cut may be used. However, when a single film 42 is used, there is a problem that wrinkles are likely to occur in the film 42 at the corner of the tip of the rib 112 or the corner of the base of the rib 112 when the film 42 is attached. Further, when one film 42 is used, there arises a problem that it is difficult to match the film 42 to the complicated shape of the lower surface 30. These problems may be solved if the film 42 is formed into a complicated shape in accordance with the protrusions such as the ribs 112. However, in order to obtain a complicated shape, it is necessary to use a mold or the like. Becomes expensive. By using the film 42 divided into a plurality, the film 42 can be easily attached along the resin-impregnated fiber 41 attached to the lower surface 30. In addition, by using the film 42 divided into a plurality, it is possible to suppress the occurrence of wrinkles that are likely to occur when the film 42 is attached to the resin-impregnated fiber 41. Furthermore, by using the divided film 42, even if air enters between the electrodeposition coating film 121 and the film 42, the effect that the air can easily escape can be expected. This effect will be described later.

  The epoxy resin impregnated in the resin-impregnated fiber 41 is cured in a state where the film 42 is adhered by a curing process described later. When the epoxy resin is cured, the surface roughness on the application surface of the film 42 is easily transferred to the surface of the fiber-containing resin coating 123. For this reason, in order to obtain the fiber-containing resin coating film 123 having a smooth surface, it is desirable to use a film having a smooth surface with a low surface roughness value. The film 42 may be thick or thin, but preferably has a certain degree of elasticity in the thickness direction. The film 42 is preferably made of a material having a good peelability with respect to the cured epoxy resin. For example, a thermoplastic resin film such as a polyethylene resin film, a polypropylene resin film, a fluorine resin film, or a nylon resin film may be used as the film 42.

  When the fiber-covered iron lid body 11 ′ having the resin-impregnated fibers 41 is prepared between the film 42 and the iron lid body 11, an burying operation for burying the fiber-covered iron lid body 11 ′ in sand is performed (step S4). ). In this embodiment, sand having an average particle size of about 0.3 mm is used, but the particle size of the sand may be large or small. In the burying operation, with the lower surface 30 of the iron lid body 11 facing upward, the fiber-covered iron lid body 11 ′ is placed in a container, and the container is filled with sand so that the fiber-covered iron lid body 11 ′ is sanded. To be buried in. The fiber-covered iron lid body 11 ′ may be buried in sand by pushing the fiber-covered iron lid body 11 ′ into a container filled with sand. Moreover, you may use granular materials, such as clay other than sand.

  Subsequently, by pressing the sand, the film 42 is pressed against the iron lid main body 11 side, and the pressing operation of pressing the resin-impregnated fiber 41 against the iron lid main body 11 side through the film 42 is performed (step S5). In the pressing work, for example, pressure may be applied to the sand by poking the sand with a heavy object or the like, or pressure may be applied to the sand using a pressure vibration device that vibrates at a predetermined frequency. The resin-impregnated fiber 41 is pressed against the iron lid main body 11 side by the pressed sand by the substantially uniform pressing force. In the state before the pressing operation, the surface of the electrodeposition coating 121 provided on the lower surface 30 of the iron lid body 11 and the resin-impregnated fiber 41, the resin-impregnated fiber 41, or the resin-impregnated fiber 41 and the film 42. Air may have entered. Even in this case, the air can be easily pushed out from the overlapping portion of the end portions of the film 42 by the pressing operation. In addition, since the electrodeposition coating 121 is formed on a rough surface to which the irregularities of the cast skin are transferred when viewed microscopically, there is a minute space between the electrodeposition coating 121 and the resin-impregnated fiber 41. ing. By the pressing operation, the resin impregnated in the resin-impregnated fiber 41 oozes out to the electrodeposition coating film 121 side, and the space can be filled with the resin oozed out from the resin-impregnated fiber 41. Moreover, since the resin-impregnated fiber 41 is pressed against the iron lid main body 11 side using sand, the air pushed out from the overlapping portion at the end of the film 42 is discharged to the outside of the container through the sand gap. Further, since the resin-impregnated fiber 41 is pressed against the iron lid main body 11 side by pressurizing sand which is a granular material having fluidity, a portion of the resin-impregnated fiber 41 attached to the side surface of the rib 112 or the like is also present. The rib 112 can be pressed with substantially the same pressing force as the flat portion 31. A wedge-shaped instrument may be inserted on the side of the rib 112. By doing so, the sand is strongly pressed toward the side surface of the rib 112, and the resin-impregnated fiber 41 can be pressed more strongly against the side surface of the rib 112. Although it is conceivable to use liquid or gas as the film 42 that presses the iron lid main body 11 side, facilities such as a pump and a compressor for sending out the liquid and gas are required. In addition, when liquid or gas is used, it is necessary to make the resin-impregnated fiber 41 airtight with the film 42 so that the liquid or gas does not enter the resin-impregnated fiber 41 side. If one undivided film 42 is used, the resin-impregnated fiber 41 can be easily airtight. However, as described above, when one film 42 is used, there is a problem that the film 42 needs to be formed in accordance with the complicated shape of the lower surface 30. By using the sand which is a granular material, there exists an advantage that it is not necessary to make the resin impregnation fiber 41 into an airtight state.

  Thereafter, until the epoxy resin impregnated in the resin-impregnated fiber 41 is cured, a curing process is performed in which the fiber-covered iron lid body 11 ′ is left buried in the sand (step S <b> 6). The sand once pressurized is maintained in its pressurized shape, and even when the pressure is stopped and left, the state where the resin-impregnated fiber 41 is pressed against the iron lid main body 11 side is maintained. However, you may continue pressurization to sand during a hardening process. In addition, in order to make it easy to maintain the shape of the pressurized sand, sand mixed with a binder may be used as sand used in the burying operation. In this embodiment, the epoxy resin impregnated in the resin-impregnated fiber 41 is cured by leaving it at room temperature for 12 to 24 hours. When it is desired to shorten the curing time, the resin-impregnated fiber 41 may be warmed by applying heat to the sand to accelerate the curing of the epoxy resin that is a thermosetting resin.

  When the curing process is completed, an extraction process for removing the fiber-covered iron lid body 11 'from the sand is performed (step S7). In this extraction process, the sand in the container may be removed to take out the fiber-attached iron lid body 11 ′, or the fiber-attached iron lid body 11 ′ buried in the sand may be grasped and pulled out from the container. When removing the sand, the sand may be sucked with a suction machine, the sand may be scooped out with a scoop or the like, and the sand may be discharged by turning the container upside down.

  When the take-out process is completed, a peeling operation for peeling the adhered film 42 from the fiber-containing resin coating film 123 is performed (step S8). In addition, although the film 42 of this embodiment uses the thing made from a polyethylene resin with high peelability with respect to the fiber-containing resin coating film 123, the thing of a material with high adhesiveness with respect to the fiber-containing resin coating film 123 is used. May be used. Moreover, when the film 42 of a material with especially high adhesiveness is used, you may leave the film 42, without peeling the film 42 from the fiber-containing resin coating film 123. FIG. By leaving the film 42, the waterproofness, corrosion resistance, and strength of the lower surface resin coating 12 can be further enhanced. Further, another coating film may be formed on the surface of the fiber-containing resin coating film 123 by brushing or the like.

  The bottom surface of the manhole cover 1 may cause condensation of a corrosive solution such as hydrogen sulfide due to the temperature difference between the basement and the manhole cover 1 and the humidity in the basement. Corrosive solution may adhere. The corrosive solution adhering to the manhole cover 1 may remain on the manhole cover 1 for a long time without dripping down due to the surface tension. If the corrosive solution remains on the manhole iron cover 1 for a long time, the corrosive solution may erode the lower surface resin film 12 or penetrate the lower surface resin film 12 and reach the iron cover body 11. The reached corrosive solution may cause rust on the iron lid main body 11.

  If the thickness of the lower surface resin coating 12 is less than 400 μm, the corrosive solution remaining on the surface of the lower surface resin coating 12 may erode all of the lower surface resin coating 12, or may penetrate into the lower surface resin coating 12 and iron There is a possibility of reaching the lid body 11. Moreover, when the impact and load from the outside are applied to the lower surface resin film 12, possibility that the lower surface resin film 12 will be destroyed increases. By setting the thickness of the lower surface resin coating 12 to 400 μm or more, the corrosive solution erodes the lower surface resin coating 12 or penetrates into the lower surface resin coating 12, and there is almost no possibility that the corrosive solution reaches the iron lid body 11.

  When a thick liquid resin is applied, the liquid resin tends to flow down by gravity on the side surfaces of the rib 112 before the resin is cured. According to the present embodiment, by using the resin-impregnated fiber 41, even if it is a portion where the resin easily flows down, such as the side surface of the rib 112, it is liquid between the reinforcing fiber and the reinforcing fiber provided in the resin-impregnated fiber 41. Therefore, the lower surface resin film 12 having a desired thickness can be easily formed. The film formation using the resin-impregnated fiber 41 may be performed a plurality of times. However, according to the present embodiment, a film having a desired thickness can be obtained even by a single film formation operation. Can be formed. Furthermore, since the resin-impregnated fiber 41 containing reinforcing fibers is used, durability against cracking and abrasion of the lower surface resin coating 12 is increased.

  Furthermore, since the resin-impregnated fiber 41 is pressed against the iron lid main body 11 side through the film 42 and the resin is cured in this state, the surface of the film 42 can be transferred to the opposite side of the resin-impregnated fiber 41. . In this embodiment, since the film 42 having a smooth surface is used, the fiber-containing resin coating film 123 having a smooth surface can be obtained. In addition, since the film 42 that is elastic in the thickness direction is used, even if the film 42 is pressed against the resin-impregnated fiber 41 using sand from the opposite side of the film 42, the shape of sand particles is applied to the surface of the film 42. Will not appear. By using such a film 42, a fiber-containing resin coating film 123 having a smooth surface according to the surface roughness of the sticking surface of the film 42 can be obtained. In addition, when the iron lid body with fiber 11 ′ is buried in sand, if fine sand having a particle size is disposed in the vicinity of the film 42, the film 42 can be used even if a thin film having low elasticity in the thickness direction is used. It is possible to prevent the shape of sand particles from appearing on the pasting surface. Since the surface of the fiber-containing resin coating 123 is smooth, the corrosive solution adhering to the fiber-containing resin coating 123 is likely to drip, and the corrosive solution is suppressed from remaining on the manhole iron lid 1 for a long time. Since the corrosive solution is prevented from remaining for a long time, the corrosive solution erodes the lower resin coating 12 or penetrates into the lower resin coating 12 to reach the iron lid main body 11 and the iron lid main body 11 is rusted. The possibility can be reduced.

  Next, the inner peripheral resin film 52 provided on the receiving frame 5 will be described.

  FIG. 7 is an enlarged view showing a D portion in FIG. In FIG. 7, the thickness of the inner peripheral resin film 52 is exaggerated. In FIG. 7, only the D portion is shown, but the inner peripheral resin film 52 is provided on the entire inner peripheral surface 61 of the receiving frame main body 51.

  As shown in FIG. 7, an inner peripheral resin film 52 is provided on the inner peripheral surface 61 of the receiving frame main body 51. The inner peripheral resin coating 52 is composed of an electrodeposition coating 521 and a fiber-containing resin coating 522. The inner peripheral resin film 52 is a resin film having the same structure as the lower surface resin film 12 provided on the manhole iron lid 1 described above. In the following description, the description which overlaps with the lower surface resin film 12 already demonstrated may be abbreviate | omitted.

  The electrodeposition coating film 521 is a coating film formed by applying electrodeposition coating using a paint mainly composed of an epoxy resin to the casting surface of the receiving frame main body 51. In addition, although the electrodeposition coating film 521 is formed not only on the inner peripheral surface 61 of the receiving frame main body 51 but also on the entire surface of the receiving frame main body 51, the electrodeposition coating film 121 may be formed only on the inner peripheral surface 61. . In FIG. 7, the thickness of the electrodeposition coating film 521 applied to other than the inner peripheral surface 61 is also exaggerated.

  The fiber-containing resin coating 522 is a coating that is in close contact with the electrodeposition coating 521. The fiber-containing resin coating 522 is a coating formed by curing the epoxy resin of the resin-impregnated fiber 71 for a receiving frame (see FIG. 8) in which a chopped strand mat is impregnated with an epoxy resin. This resin-impregnated fiber 71 for receiving frames is a sheet-like thing divided | segmented into plurality, and is arrange | positioned so that each edge part may overlap. For this reason, the fiber-filled resin coating film 522 constituted by the resin-impregnated fibers 71 for receiving frames has a thick portion 522 a formed at the overlapping portion of the resin-impregnated fibers 71 for receiving frames.

  The method for creating the inner peripheral resin coating 52 is the same as the method for creating the lower resin coating 12. In the following description, the description which overlaps with the preparation method of the lower surface resin film 12 already demonstrated may be abbreviate | omitted. First, electrodeposition coating is applied to the entire surface of the receiving frame main body 51, and then a pasting operation is performed. In the pasting operation, resin impregnated fibers 71 for receiving frames that are finely cut according to the shape of the inner peripheral surface 61 are used. The portion of the receiving frame resin-impregnated fiber 71 that is affixed to the hinge 62 side is also finely cut in the same manner as the portion that is affixed to the locking piece 63, but here the locking piece 63 is used. The part affixed on the side will be described, and the description of the part affixed on the hinge 62 side will be omitted.

  FIG. 8 is a cross-sectional view of the vicinity of the locking piece, showing an example of the positional relationship between the resin-impregnated fiber for receiving frame to be attached in the attaching operation and the film for receiving frame to be attached in the covering operation. In FIG. 8, the resin-impregnated fiber 71 for receiving frames is shown by a thick solid line.

  As shown in FIG. 8, the resin-impregnated fiber 71 for receiving frames is divided in the vicinity of a portion where the inner peripheral surface 61 is changed to an acute angle. In the vicinity of the locking piece 63, the resin-impregnated fiber 71 for receiving frames is divided into an upper-side resin-impregnated fiber 711, an intermediate-portion resin-impregnated fiber 712, and a lower-side resin-impregnated fiber 713. In the pasting operation, first, the lower resin-impregnated fiber 713 is pasted, then the intermediate resin-impregnated fiber 712 is pasted, and then the upper resin-impregnated fiber 711 is pasted. Since the upper resin-impregnated fiber 711, the intermediate resin-impregnated fiber 712, and the lower resin-impregnated fiber 713 are formed in a sheet shape, they can be easily attached along the shape of the inner peripheral surface 61. . The order in which the lower resin-impregnated fiber 713, the intermediate resin-impregnated fiber 712, and the upper resin-impregnated fiber 711 are attached is not limited to the above order, and may be any order.

  When the upper resin impregnated fiber 711, the intermediate resin impregnated fiber 712, and the lower resin impregnated fiber 713 are attached to the electrodeposition coating 521 provided on the inner peripheral surface 61, the respective end portions overlap each other. It is cut to a size that can be matched. As long as the entire inner peripheral surface 61 can be covered, the receiving frame resin-impregnated fiber 71 may be cut into an arbitrary size. Further, the upper resin-impregnated fiber 711, the intermediate resin-impregnated fiber 712, and the lower resin-impregnated fiber 713, and the upper resin-impregnated fiber 711, which are cut to a size that can be attached to each other, are attached. Resin-impregnated fibers 712 and lower resin-impregnated fibers 713 may be used.

  In the covering operation, a receiving frame is formed on the surface of the receiving frame resin-impregnated fiber 71 (hereinafter sometimes referred to as the opposite surface) opposite to the application surface of the receiving frame resin-impregnated fiber 71 bonded to the electrodeposition coating film 521. A film 72 is pasted. By electrodeposition coating, pasting work, and covering work, a fiber-attached receiving frame main body 51 ′ shown in FIG. 8 provided with a receiving frame resin-impregnated fiber 71 between the receiving frame film 72 and the receiving frame main body 51 is obtained. The fiber-attached receiving frame main body 51 ′ of this embodiment corresponds to an example of a fiber-attached structure in the present invention. In FIG. 8, a gap is shown between the film 72 for the receiving frame and the resin-impregnated fiber 71 for the receiving frame, and between the electrodeposition coating film 521 provided on the inner peripheral surface 61 and the resin-impregnated fiber 71 for the receiving frame. However, the frame-receiving frame main body 51 ′ to which the frame-receiving film 72 without gaps, the resin-impregnated fiber 71 for frame, and the electrodeposition coating film 521 are attached. The frame film 72 is a polyethylene resin sheet having a thickness of 0.15 mm. The receiving frame film 72 includes an upper film 721 cut to be approximately the same size as the upper resin-impregnated fiber 711, an intermediate film 722 cut to be slightly larger than the intermediate-part resin-impregnated fiber 712, and a lower side. It is divided in advance into a lower film 723 cut to substantially the same size as the resin impregnated fiber 713. In the covering operation, first, the intermediate film 722 is attached to the opposite surface of the intermediate resin impregnated fiber 712, then the upper film 721 is attached to the opposite surface of the upper resin impregnated fiber 711, and then the lower film. 723 is attached to the opposite surface of the lower resin impregnated fiber 713. The order in which the upper film 721, the intermediate film 722, and the lower film 723 are attached is not limited to the above order, and may be any order. When the covering operation is completed, the entire opposite surface of the receiving frame resin-impregnated fiber 71 is covered with the receiving frame film 72.

  As shown in FIG. 8, the end portions of the upper film 721, the intermediate film 722, and the lower film 723 are arranged so as to overlap each other. By arranging the end portions of the upper film 721, the intermediate film 722, and the lower film 723 so as to overlap each other, the entire opposite surface of the frame-impregnated resin-impregnated fiber 71 can be reliably covered with the frame film 72. it can.

  When the covering operation is completed, the burying operation of burying the fiber receiving frame main body 51 ′ in the sand is performed with the posture reversed from the posture arranged on the upper part of the manhole shown in FIG. 1. Then, the receiving frame 5 provided with the inner peripheral resin film 52 is obtained by sequentially performing the pressing work, the curing process, the removing process, and the peeling work.

  The thickness of the inner peripheral resin film 52 is desirably 400 μm or more, like the lower surface resin film 12. Further, in order to make the corrosive solution sag easily, it is desirable that the surface of the inner peripheral resin film 52 be a smooth surface. According to the method for producing the inner peripheral resin coating 52 of the present embodiment, the lower surface resin coating 12 having a desired thickness can be easily formed. In addition, a fiber-containing resin coating 522 having a smooth surface can be obtained.

  As described above, according to the present embodiment, by using sand, the fiber-containing resin coating film 123 and the fiber-containing resin coating film are in close contact with the shape of the iron lid main body 11 and the receiving frame main body 51 without using a mold. 522 can be formed. Further, since the resin-impregnated fiber 41 and the resin-impregnated fiber 71 for receiving frames are used, the resin coatings 12 and 52 having a desired thickness can be easily formed on portions such as the side surfaces of the rib 112 where liquid resin is likely to sag. Since the resin coatings 12 and 52 having a desired thickness can be easily formed on a structure having protrusions or recesses on the surface of the manhole iron lid 1 or the receiving frame 5 without using a mold, even in the case of producing a variety of products in small quantities. A structure including the resin coatings 12 and 52 having a desired thickness can be produced at low cost. Although it is conceivable to form a resin film by vacuum forming or thermal spraying, a large facility is required to perform vacuum forming or thermal spraying, and the structure provided with the resin film is expensive. Become. According to this embodiment, the resin coatings 12 and 52 can be easily formed without a large facility. Furthermore, since the resin-impregnated fibers 41 and the resin-impregnated fibers 71 for receiving frames are pressed through the film 42 and the film 72 for receiving frames, smooth surfaces can be formed on the surfaces of the resin coatings 12 and 52. Since the resin films 12 and 52 having a large film thickness and a smooth surface can be formed, the corrosive solution is likely to sag as described above, and the possibility that rust is generated in the iron lid body 11 and the receiving frame body 51 is suppressed. . Moreover, possibility that the metal which comprises the iron cover main body 11 and the receiving frame main body 51 will be melt | dissolved by corrosive solution is also suppressed.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the claims. For example, in this embodiment, the resin-impregnated fiber 41 is attached to the iron lid body 11 provided with the electrodeposition coating film 121, and then covered with the film 42. The resin-impregnated fiber 41 covered with the film 42 and covered with the film 42 may be attached to the iron lid main body 11. Similarly, the resin-impregnated fiber 71 for receiving frame covered with the film 72 for receiving frame may be attached to the receiving frame main body 51. Moreover, in this embodiment, although the lower surface resin film 12 was formed in the whole lower surface 30 of the manhole iron lid 1, you may form the lower surface resin film 12 in the part of the lower surface 30 which is especially worried about rust. Similarly, the inner peripheral resin film 52 may be formed only on a part of the inner peripheral surface 61 where rust is particularly concerned. Further, the fiber-containing resin coating film 123 may be formed on the entire surface of the iron lid main body 11, or the fiber-containing resin coating film 522 may be formed on the entire surface of the receiving frame main body 51. Alternatively, the electrodeposition coating 121 may be omitted, and the fiber-containing resin coating 123 may be formed directly on the casting surface of the iron lid body 11. Similarly, the electrodeposition coating film 521 may be omitted, and the fiber-filled resin coating film 522 may be formed directly on the casting surface of the receiving frame main body 51. Further, in the present embodiment, the cast iron manhole iron lid 1 has been described, but the present invention may be applied to a plastic lid body. Moreover, although the example which forms a resin film in the manhole iron lid 1 and the receiving frame 5 was demonstrated in this embodiment, for example in structures, such as an underground structure other than the manhole iron cover 1 and the receiving frame 5, a house veranda, or a ship. A resin film may be formed. Furthermore, the structure forming the resin film may be made of plastic or wood, and the material is not limited.

  Even if the configuration requirement or the creation method is included only in the description of each modification described above, the configuration requirement or the creation method may be applied to another modification.

DESCRIPTION OF SYMBOLS 1 Manhole iron lid 5 Receiving frame 11 Iron lid main body 11 'Iron lid main body with fiber 12 Lower surface resin coating 30 Lower surface 41 Resin-impregnated fiber 42 Film 51 Receiving frame main body 51' Receiving frame main body with fiber 52 Inner peripheral resin coating 61 Inner peripheral surface 71 For receiving frame Resin-impregnated fiber 72 Film for receiving frame 123, 522 Fiber-coated resin coating 411 Resin-impregnated fiber for flat part 412 Resin-impregnated fiber for rib 421 Film for flat part 422 Film for rib 423 Film for gap 711 Upper part resin-impregnated fiber 712 Intermediate part Resin-impregnated fiber 713 Lower resin-impregnated fiber 721 Upper film 722 Middle film 723 Lower film

Claims (5)

In a resin film forming method of forming a resin film on a structure using a resin-impregnated fiber in which a resin is impregnated between fibers,
A preparation step of preparing a fiber-attached structure including the resin-impregnated fibers between a resin film and the structure;
An burying step of burying the structure with fibers prepared in the preparation step in a granular material;
A pressing step of pressing the resin-impregnated fiber against the structure side by pressurizing the granular material;
And a curing step of curing the resin impregnated in the resin-impregnated fiber provided in the structure with fiber embedded in the granular material pressurized in the pressing step. Forming method.   The preparation step is a step of preparing the structure having the resin-impregnated fibers between a plurality of the resin films arranged so as to be overlapped with each other. 2. The method for forming a resin film according to 1.   The resin film forming method according to claim 1, wherein the preparing step is a step of preparing the structure having the resin-impregnated fibers cut into a plurality of sheets. In the cover for the underground structure that closes the opening that leads to the underground structure,
A metal lid body;
A lower surface resin coating provided on the lower surface of the lid body that becomes the underground side,
The lower surface resin coating is a cover for an underground structure, wherein at least a part thereof is formed by a sheet-like resin-impregnated fiber impregnated with a resin between fibers. In the underground structure lid receiving frame that supports the underground structure lid that closes the opening connected to the underground structure,
A metal receiving frame body formed in a cylindrical shape;
An inner peripheral resin film provided on the inner peripheral surface of the receiving frame body,
A cover frame for an underground structure, wherein the inner peripheral resin coating is at least partly formed of a sheet-like resin-impregnated fiber in which a resin is impregnated between fibers.

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