Methods for preventing rail corrosion, rail repair structures

Abstract

This invention provides a method for preventing rail corrosion in which the fiber-reinforced prepreg sheet is less likely to lift from the rail and is easy to install. [Solution] A method for preventing rail corrosion, comprising covering the bottom 13 of the rail 10 with a fiber-reinforced prepreg sheet 20, and covering both sides of the body 12 of the rail 10 that is continuous with the bottom 13 of the rail 10 with the fiber-reinforced prepreg sheet 20.

Description

[Technical Field]

[0001] This invention relates to a method for preventing corrosion of rails and a repair structure for rails. [Background technology]

[0002] Electricity, which powers trains, flows through the rails. As a result, the rails are prone to corrosion. Even slight corrosion can cause the rails to break. Therefore, methods to prevent rail corrosion include, for example, the tape method, which involves wrapping tape around the bottom of the rail to prevent corrosion, and the aramid fiber method, which involves wrapping aramid fibers around the bottom of the rail and then impregnating the aramid fibers with resin to further prevent corrosion (see Patent Document 1).

[0003] However, the tape method has the drawback of having low abrasion resistance, and when the tape is used on-site, it deteriorates and corrodes the rails.

[0004] The aramid fiber method is a construction method in which resin is impregnated into aramid fibers on-site, which presents challenges in terms of workability. The aramid fiber method involves a surface preparation step, a primer application step, an epoxy resin application step, an aramid fiber attachment step, a top coat epoxy resin application step, an impregnation step of the aramid fibers with the aforementioned resin, and a curing step of the aforementioned resin, making it a complicated process that requires skilled resin impregnation techniques from the workers.

[0005] One known method for solving the problem of ease of construction is the fiber-reinforced prepreg sheet method. The fiber-reinforced prepreg sheet method involves attaching a fiber-reinforced prepreg sheet, in which reinforcing fibers are impregnated with resin, to the object. The fiber-reinforced prepreg sheet method includes a surface preparation step, a primer application step, an adhesive application step, a fiber-reinforced prepreg sheet attachment step, and a hardening step for the resin contained in the fiber-reinforced prepreg sheet. The fiber-reinforced prepreg sheet method is used for steel structures such as steel pipes and pedestrian bridges. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2019-108768 [Overview of the project] [Problems that the invention aims to solve]

[0007] For the above-mentioned fiber-reinforced prepreg sheet to be applied to rail corrosion, the fiber-reinforced prepreg sheet needs to be able to conform to the complex shape of a rail and be adhered to that complex shape.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a method for preventing corrosion of rails and a rail repair structure that makes it difficult for fiber-reinforced prepreg sheets to lift from the rails and is easy to install. [Means for solving the problem]

[0009] The present invention has the following aspects. [1] A method for preventing corrosion of a rail, comprising covering the bottom of the rail with a fiber-reinforced prepreg sheet and covering both sides of the rail's body, which is continuous with the bottom of the rail, with the fiber-reinforced prepreg sheet. [2] A step of applying primer to the bottom and sides of the rail, The process involves applying adhesive to the bottom and sides of the rail via the primer, A step of attaching a fiber-reinforced prepreg sheet to the adhesive-coated surface at the bottom and underside of the rail, A method for preventing corrosion of rails according to [1], comprising the step of curing the fiber-reinforced prepreg sheet by ultraviolet irradiation. [3] A step of applying primer to the bottom and underside of the rail, The process involves applying adhesive to a fiber-reinforced prepreg sheet, The process of attaching the adhesive-coated surface of the fiber-reinforced prepreg sheet to the bottom and underside of the rail via the primer, A method for preventing corrosion of rails according to [1], comprising the step of curing the fiber-reinforced prepreg sheet by ultraviolet irradiation. [4] The method for preventing corrosion of rails according to any one of [1] to [3], wherein the fiber-reinforced prepreg sheet comprises glass fibers and a curable resin. [5] The method for preventing corrosion of rails according to any one of [1] to [4], wherein the thickness of the fiber-reinforced prepreg sheet is 3.0 mm or less. [6] The method for preventing corrosion of rails according to [4], wherein the curable resin is a photocurable vinyl ester resin. [7] The fiber-reinforced prepreg sheet has flame retardancy or better as determined by a flammability test for railway vehicles, as described in any of [1] to [6] for the method of preventing corrosion of rails. [8] A method for preventing corrosion of a rail according to any one of [1] to [7], wherein a plurality of fiber-reinforced prepreg sheets are used, and a portion of the plurality of fiber-reinforced prepreg sheets overlap each other in the longitudinal direction of the rail. [9] A rail repair structure comprising a rail and a fiber-reinforced prepreg sheet covering both sides of the bottom of the rail and the body of the rail continuous with the bottom. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a rail corrosion prevention method and a rail repair structure in which a fiber-reinforced prepreg sheet is less likely to lift off the rail and construction is easy. [Brief Description of the Drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view showing a rail corrosion prevention method and a rail repair structure according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing a flammability test of a fiber-reinforced prepreg sheet used in the rail corrosion prevention method according to an embodiment of the present invention. [Figure 3] FIG. 3 is a perspective view showing a method of attaching a fiber-reinforced prepreg sheet used in the rail corrosion prevention method according to an embodiment of the present invention. [Figure 4] FIG. 4 is a cross-sectional view showing a method of attaching a fiber-reinforced prepreg sheet used in the rail corrosion prevention method according to an embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view showing a method for measuring the bending strength of a laminate including a steel plate and a fiber-reinforced prepreg sheet in Examples 5 to 8. [Figure 6] FIG. 6 is a cross-sectional view showing a method for measuring the bending strength of a laminate including a steel plate and a fiber-reinforced prepreg sheet in Examples 5 to 10. [Figure 7] FIG. 7 is a cross-sectional view showing a method for measuring the bending strength of a laminate including a steel plate and a fiber-reinforced prepreg sheet in Example 9. [Figure 8] FIG. 8 is a cross-sectional view showing a method for measuring the bending strength of a laminate including a steel plate and a fiber-reinforced prepreg sheet in Example 10. [Mode for Carrying Out the Invention]

[0012] Hereinafter, embodiments of the rail corrosion prevention method and rail repair structure of the present invention will be described with reference to embodiments. However, the present invention is not limited to the following embodiments.

[0013] Figure 1 is a cross-sectional view showing a method for preventing rail corrosion and a rail repair structure according to one embodiment of the present invention. Please note that the drawings used in the following explanation may be enlarged for clarity, highlighting key features, and therefore the dimensional ratios of each component may differ from those of the actual components.

[0014] [Methods for preventing rail corrosion] The method for preventing rail corrosion in this embodiment involves covering the bottom of the rail with a fiber-reinforced prepreg sheet, and covering both sides of the rail's body, which is continuous with the bottom of the rail, with the same fiber-reinforced prepreg sheet.

[0015] The rail corrosion prevention method of this embodiment preferably comprises the steps of: applying a primer to the bottom and sides of the rail (hereinafter referred to as "step A1"), applying an adhesive to the bottom and sides of the rail via the primer (hereinafter referred to as "step B1"), attaching a fiber-reinforced prepreg sheet to the adhesive-coated surfaces on the bottom and sides of the rail (hereinafter referred to as "step C1"), and curing the fiber-reinforced prepreg sheet by ultraviolet irradiation (hereinafter referred to as "step D1").

[0016] As shown in Figure 1, the rail 10 has a head 11, a body 12, and a bottom 13. The rail 10 has a bottom 13, a body 12, and a head 11 that are continuous in order from vertically downward to upward. The base portion 13 has a roughly triangular cross-sectional shape. The base portion 13 has a base surface 13a that contacts the installation surface such as the surface of the sleeper, and one base upper surface 13b and the other base upper surface 13c that are continuous with the base surface 13a and rise from one end 13d and the other end 13e of the base portion 13. The abdomen 12 has a roughly rectangular cross-sectional shape. The abdomen 12 has two sides (one abdominal side 12a and the other abdominal side 12b) that are continuous with one bottom upper surface 13b and the other bottom upper surface 13c of the bottom 13. The head 11 has a roughly rectangular cross-sectional shape.

[0017] In the rail corrosion prevention method of this embodiment, it is preferable to perform surface preparation (priming) on ​​the surface of the rail 10, particularly both sides of the belly 12 of the rail 10 (one belly side 12a and the other belly side 12b), the bottom surface 13a of the bottom 13 of the rail 10, and one bottom upper surface 13b and the other bottom upper surface 13c of the bottom 13 of the rail 10, in order to remove rust before step A1.

[0018] Methods for surface preparation include, for example, scraping with a grinder or sandpaper.

[0019] "Process A1" In step A1, primer is applied to the bottom 13 and belly 12 of the rail 10. Specifically, primer is applied to both sides of the belly 12 of the rail 10 (one belly side 12a and the other belly side 12b), one boundary 12c and the other boundary 12d between the belly 12 and the bottom 13, the bottom surface 13a of the bottom 13 of the rail 10, one bottom upper surface 13b and the other bottom upper surface 13c of the bottom 13 of the rail 10, and one end 13d and the other end 13e of the bottom 13 of the rail 10.

[0020] The method for applying the primer to the bottom 13 and side 12 of the rail 10 is not particularly limited, but for example, a brush application method, a roller application method, a spray application method, etc., can be used.

[0021] The amount of primer applied is 0.05 kg / m² per unit area of ​​the surface of the bottom 13 and side 12 of the rail 10. 2 More than 0.25kg / m 2 Preferably, it is 0.1 kg / m 2 More than 0.2kg / m 2 The following is more preferable: If the amount of primer applied is equal to or greater than the lower limit, the adhesion between the bottom 13 and the surface of the underside 12 of the rail 10 and the adhesive can be improved. If the amount of primer applied is equal to or less than the upper limit, the primer can be applied uniformly to the object.

[0022] Examples of primers include epoxy resin primers, urethane resin primers, polyester resin primers, and polypropylene resin primers. Among these, urethane resin primers are preferred from the viewpoint of workability.

[0023] After applying the primer, allow it to cure until the tackiness (stickiness) disappears.

[0024] "Process B1" In step B1, adhesive is applied to the bottom 13 and side 12 of the rail 10 via the primer applied in step A1. Specifically, adhesive is applied via the primer to both sides of the side 12 of the rail 10 (one side 12a and the other side 12b), the bottom surface 13a of the bottom 13 of the rail 10, and one top bottom surface 13b and the other top bottom surface 13c of the bottom 13 of the rail 10.

[0025] The method for applying adhesive to the bottom 13 and side 12 of the rail 10 is not particularly limited, but for example, a brush application method, a spray application method, etc., can be used.

[0026] The amount of adhesive to be applied is 0.05 kg / m² per unit area of ​​the surface of the bottom 13 and underside 12 of the rail 10. 2 More than 0.25kg / m 2 Preferably, it is 0.1 kg / m 2 More than 0.2kg / m 2 The following is more preferable: If the amount of adhesive applied is equal to or greater than the lower limit, the bottom 13 and the surface of the body 12 of the rail 10 can be sufficiently bonded to the fiber-reinforced prepreg sheet 20. If the amount of adhesive applied is equal to or less than the upper limit, workability is improved.

[0027] As the adhesive, a two-part adhesive is preferred. Examples of two-part adhesives include epoxy resin adhesives and vinyl ester resin adhesives. Among these, vinyl ester resin adhesives are preferred from the viewpoint of corrosion resistance.

[0028] "Process C1" In step C1, first, the fiber-reinforced prepreg sheet 20 is attached to one abdominal side surface 12a of the rail 10 to which the adhesive has been applied. Next, the fiber-reinforced prepreg sheet 20 is folded at the boundary 12c between the abdominal part 12 and the bottom part 13 and attached to one upper bottom surface 13b of the bottom part 13 of the rail 10. Next, the fiber-reinforced prepreg sheet 20 is folded at one end 13d of the bottom part 13 of the rail 10 and attached to the bottom surface 13a of the bottom part 13 of the rail 10. Next, the fiber-reinforced prepreg sheet 20 is folded at the other end 13e of the bottom part 13 of the rail 10 and attached to the other upper bottom surface 13c of the bottom part 13 of the rail 10. Next, the fiber-reinforced prepreg sheet 20 is folded at the boundary 12d between the abdominal part 12 and the bottom part 13 and attached to the other abdominal side surface 12b of the rail 10.

[0029] The fiber-reinforced prepreg sheet 20 is an uncured resin sheet containing a reinforcing member and a curable resin. The curable resin is impregnated into the reinforcing member.

[0030] Examples of reinforcing materials include inorganic fibers such as glass fibers, organic fibers such as vinylon fibers, and metallic fibers such as carbon fibers and steel fibers. Among these, glass fibers are preferred from a cost viewpoint.

[0031] The form of the fibers is not particularly limited, and examples include: a form in which fibers such as tow, cross, chop diver, and continuous fibers are aligned in one direction; a form in which continuous fibers are used as warp and weft to form a woven fabric; a form in which tow fibers are aligned in one direction and held in place by auxiliary weft threads; a form of multiaxial warp knit in which multiple fiber sheets with fibers aligned in one direction are overlapped so that the direction of each fiber is different and stitched together with auxiliary threads; and a form of nonwoven fabric of fibers. Among these, nonwoven fabrics are preferred from the viewpoint of the isotropically arranged fibers.

[0032] Examples of curable resins include photocurable vinyl ester resins, photocurable unsaturated polyester resins, and photocurable epoxy resins. Among these, photocurable vinyl ester resins are preferred from the viewpoint of corrosion resistance.

[0033] The fiber-reinforced prepreg sheet 20 has a basis weight of 450 g / m 2 or more and 1050 g / m 2 or less, more preferably 600 g / m 2 or more and 900 g / m 2 or less. When the basis weight is equal to or more than the above lower limit, the fiber-reinforced prepreg sheet 20 is excellent in corrosion resistance. When the basis weight is equal to or less than the above upper limit, the fiber-reinforced prepreg sheet 20 is excellent in flexibility, and can be easily deformed along and attached to both side surfaces of the web 12 of the rail 10 (one web side surface 12a and the other web side surface 12b), one boundary 12c and the other boundary 12d between the web 12 and the base 13, the bottom surface 13a of the base 13 of the rail 10, one base upper surface 13b and the other base upper surface 13c of the base 13 of the rail 10, and one end 13d and the other end 13e of the base 13 of the rail 10.

[0034] The fiber-reinforced prepreg sheet 20 preferably has a thickness of 3.0 mm or less, more preferably 2.0 mm or less. When the thickness is equal to or less than the above upper limit, the fiber-reinforced prepreg sheet 20 is excellent in flexibility, and can be easily deformed along and attached to both side surfaces of the web 12 of the rail 10 (one web side surface 12a and the other web side surface 12b), one boundary 12c and the other boundary 12d between the web 12 and the base 13, the bottom surface 13a of the base 13 of the rail 10, one base upper surface 13b and the other base upper surface 13c of the base 13 of the rail 10, and one end 13d and the other end 13e of the base 13 of the rail 10.

[0035] The fiber-reinforced prepreg sheet 20 preferably has a thickness of 1 mm or more, more preferably 1.5 mm or more. When the thickness is equal to or more than the above lower limit, the fiber-reinforced prepreg sheet 20 is excellent in corrosion resistance. Furthermore, the fiber-reinforced prepreg sheet 20 that is attached to the adhesive-coated surfaces of the bottom 13 and body 12 of the rail 10 may be a single continuous sheet or a combination of two or more sheets. In order to simplify the process of attaching it to the rail 10, a single continuous sheet of fiber-reinforced prepreg sheet 20 is preferred.

[0036] The fiber-reinforced prepreg sheet 20 preferably has flame retardancy as determined by flammability tests for railway vehicles. More preferably, it is non-flammable. During maintenance and inspection, the rails are subjected to a grinding machine that grinds the rail heads, causing sparks to fly onto the fiber-reinforced prepreg sheets. Therefore, the fiber-reinforced prepreg sheets 20 must be flame-retardant or better (they must not burn once the source of the fire is removed) when attached to the iron (rails).

[0037] This section explains flammability testing for railway vehicles. Flammability tests for railway vehicles shall be conducted in accordance with the methods described in "Guidance on Flammability Testing of Materials for Railway Vehicles: Combustion Tests, JRMA (Japan Railway Rolling Stock and Machinery Technology Association)." The combustion test (non-metallic material for railway vehicles) method is as shown in Figure 2. A B5 test specimen (182 mm x 257 mm) 110 is held at a 45° incline, and placed on a stand 130 made of a material with low thermal conductivity, such as cork, so that the center of the bottom of the fuel container 120 is 25.4 mm (1 inch) vertically below the center of the underside (combustion surface) of the test specimen 110. 0.5 mL of pure ethyl alcohol is poured into the fuel container 120 and ignited, and left until the pure ethyl alcohol burns out. Combustion is evaluated separately during and after the combustion of pure ethyl alcohol. During the combustion of pure ethyl alcohol, ignition, flame formation, smoke emission, and flame condition of the test material 110 are observed. After the combustion of pure ethyl alcohol, the afterflame, residue, carbonization, and deformation are investigated. For the pre-test treatment of the test specimen 110, if the test specimen 110 is made of a hygroscopic material, it is prepared to the specified dimensions and left in a well-ventilated room away from direct sunlight and at least 1 meter from the floor for at least 5 days. The conditions inside the test chamber are: temperature: 15°C to 30°C, humidity: 60% to 75%, and no airflow.

[0038] Furthermore, in step C1, it is preferable to use multiple fiber-reinforced prepreg sheets 20, with the multiple fiber-reinforced prepreg sheets 20 partially overlapping each other in the longitudinal direction of the rail 10. For example, as shown in Figures 3 and 4, a case in which a first fiber-reinforced prepreg sheet 21 and a second fiber-reinforced prepreg sheet 22 are used as the fiber-reinforced prepreg sheets 20 will be described. For example, a case in which the first fiber-reinforced prepreg sheet 21 and the second fiber-reinforced prepreg sheet 22 are attached to one bottom upper surface 13b, the other end 13e of the bottom 13, and the bottom surface 13a of the bottom 13 of the rail 10 will be described. Primer 40 is applied to one upper bottom surface 13b of the bottom 13 of the rail 10, the other end 13e of the bottom 13, and the bottom surface 13a of the bottom 13. Next, adhesive 50 is applied via primer 40 to one top surface 13b of the bottom 13 of the rail 10, the other end 13e of the bottom 13, and the bottom surface 13a of the bottom 13. Next, the first fiber-reinforced prepreg sheet 21 is attached to one top surface 13b of the bottom 13 of the rail 10, the other end 13e of the bottom 13, and the bottom surface 13a of the bottom 13 via adhesive 50. Next, the second fiber-reinforced prepreg sheet 22 is attached to one upper bottom surface 13b, the other end 13e, and the bottom surface 13a of the bottom 13 of the rail 10 via adhesive 50. At this time, one end 22a of the second fiber-reinforced prepreg sheet 22 in the longitudinal direction of the rail 10 is overlapped with one end 21a of the first fiber-reinforced prepreg sheet 21 in the longitudinal direction of the rail 10. In this case, it is preferable that one end 21a of the first fiber-reinforced prepreg sheet 21 and one end 22a of the second fiber-reinforced prepreg sheet 22 are bonded together, for example, via a primer and adhesive applied to one end 21a of the first fiber-reinforced prepreg sheet 21. In this way, after attaching the fiber-reinforced prepreg sheet 20 to the rail 10, the shielding between the external environment and both sides of the abdominal portion 12 of the rail 10 (one abdominal side 12a and the other abdominal side 12b), one boundary 12c and the other boundary 12d between the abdominal portion 12 and the bottom portion 13, the bottom surface 13a of the bottom portion 13 of the rail 10, one bottom upper surface 13b and the other bottom upper surface 13c of the bottom portion 13 of the rail 10, and one end 13d and the other end 13e of the bottom portion 13 of the rail 10 can be maintained.

[0039] The overlapping length (W shown in Figure 4) between one end 21a of the first fiber-reinforced prepreg sheet 21 and one end 22a of the second fiber-reinforced prepreg sheet 22 is preferably 0 mm or more, and more preferably 10 mm or more. However, the most preferable is to attach the entire length of the rail with a single prepreg sheet. When the length W is within the above range, after the fiber-reinforced prepreg sheet 20 is attached to the rail 10, the prepreg sheet is less likely to peel off the rail in the portion of the rail 10 to which the fiber-reinforced prepreg sheet 20 is attached, thus maintaining isolation from the external environment.

[0040] "Process D1" In process D1, the fiber-reinforced prepreg sheet 20 is cured by ultraviolet irradiation. In step D1, the amount of ultraviolet irradiation is not particularly limited and is adjusted as appropriate depending on the type and amount of curable resin contained in the fiber-reinforced prepreg sheet 20.

[0041] Through the above process, the bottom 13 of the rail 10 is covered with the fiber-reinforced prepreg sheet 20, and both sides of the body 12 of the rail 10 that is continuous with the bottom 13 of the rail 10 are also covered with the fiber-reinforced prepreg sheet 20, thereby completing the work to prevent corrosion of the rail.

[0042] According to the rail corrosion prevention method of this embodiment, the fiber-reinforced prepreg sheet attached to the rail is less likely to lift, and rail corrosion prevention can be easily implemented. Therefore, it is possible to prevent electrolytic corrosion of the rail caused by leakage current from contact points between the rail fixing jig and the rail, the bottom of the rail, etc.

[0043] [Repair structure for rails] The rail repair structure of this embodiment comprises a rail and a fiber-reinforced prepreg sheet that covers both sides of the bottom of the rail and the body of the rail that is continuous with the bottom.

[0044] The rail repair structure of this embodiment is a structure obtained by repairing the rail using the rail corrosion prevention method of the above-described embodiment. As shown in Figure 1, the rail repair structure 30 of this embodiment includes a rail 10 and a fiber-reinforced prepreg sheet 20 that covers both sides of the bottom 13 of the rail 10 and the body 12 of the rail 10 that is continuous with the bottom 13. The fiber-reinforced prepreg sheet 20 covering the bottom 13 and body 12 of the rail 10 may be a single continuous sheet or a combination of two or more sheets. To prevent tearing at the joints between the fiber-reinforced prepreg sheets, a single continuous sheet of fiber-reinforced prepreg sheet 20 is preferable.

[0045] According to the rail repair structure of this embodiment, since the bottom and both sides of the rail are covered with a fiber-reinforced prepreg sheet, it is possible to prevent electrolytic corrosion of the rail caused by leakage current from contact points between the rail fixing jig and the rail, the bottom of the rail, etc.

[0046] [Other embodiments] However, the present invention is not limited to the embodiments described above.

[0047] For example, the following modified versions may be adopted.

[0048] [Methods for preventing rail corrosion] The rail corrosion prevention method of this embodiment comprises the steps of: applying a primer to the bottom and sides of the rail (hereinafter referred to as "step A2"), applying an adhesive to a fiber-reinforced prepreg sheet (hereinafter referred to as "step B2"), attaching the adhesive-coated side of the fiber-reinforced prepreg sheet to the bottom and sides of the rail via the primer (hereinafter referred to as "step C1"), and curing the fiber-reinforced prepreg sheet by ultraviolet irradiation (hereinafter referred to as "step D2").

[0049] In the rail corrosion prevention method of this embodiment, it is preferable to perform surface preparation (priming) on ​​the surface of the rail 10 to remove rust before step A2.

[0050] "Process A2" In step A2, a primer is applied to the bottom 13 and underside 12 of the rail 10, similar to step A1 described above.

[0051] "Process B2" In step B2, an adhesive is applied to the fiber-reinforced prepreg sheet 20. The method for applying the adhesive to the fiber-reinforced prepreg sheet 20 is not particularly limited, but for example, a brush application method, a spray application method, a dipping method, etc., can be used. The same adhesive used in step B1 described above is used.

[0052] The amount of adhesive to be applied is 0.5 kg / m² per unit area of ​​the surface of the fiber-reinforced prepreg sheet 20. 2 More than 2.0kg / m 2 Preferably, it is 0.7 kg / m 2 More than 1.2kg / m 2 The following is more preferable: If the amount of adhesive applied is equal to or greater than the lower limit, the bottom 13 and the surface of the body 12 of the rail 10 can be sufficiently bonded to the fiber-reinforced prepreg sheet 20. If the amount of adhesive applied is equal to or less than the upper limit, workability is improved. Furthermore, the fiber-reinforced prepreg sheet 20 may be a single continuous sheet or a combination of two or more sheets. In order to simplify the process of attaching it to the rail 10, a single continuous sheet of fiber-reinforced prepreg sheet 20 is preferable.

[0053] "Process C2" In step C2, the adhesive-coated side of the fiber-reinforced prepreg sheet 20 is attached to the bottom 13 and underside 12 of the rail 10 via a primer, in the same manner as in step C1 above.

[0054] "Process D2" In process D2, the fiber-reinforced prepreg sheet 20 is cured by ultraviolet irradiation.

[0055] Through the above process, the bottom 13 of the rail 10 is covered with the fiber-reinforced prepreg sheet 20, and both sides of the body 12 of the rail 10 that is continuous with the bottom 13 of the rail 10 are also covered with the fiber-reinforced prepreg sheet 20, thereby completing the work to prevent corrosion of the rail.

[0056] According to the rail corrosion prevention method of this embodiment, the adhesive can be applied to the bonding surface of the fiber-reinforced prepreg sheet 20 by utilizing the primer curing time, thereby reducing the construction time.

[0057] While embodiments of this invention have been described in detail with reference to the drawings above, these embodiments are merely illustrative examples of the invention. Therefore, this invention is not limited to the configurations of the embodiments, and any design changes, etc., that do not depart from the gist of this invention are also included. Furthermore, for example, if each embodiment includes multiple configurations, it goes without saying that possible combinations of these configurations are included, even if not specifically stated. Also, if multiple examples or variations are disclosed as part of this invention within an embodiment, it goes without saying that possible combinations of configurations spanning these are included, even if not specifically stated. Moreover, configurations depicted in the drawings are included, even if not specifically stated. Furthermore, where the term "etc." is used, it means that equivalent items are included. [Examples]

[0058] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0059] [Example 1] The surfaces of the rail's underside, the bottom of the rail, and the top of the rail's bottom were prepared with sandpaper to remove rust. Next, I wiped off the rust particles from the surface of the rails with a cloth soaked in acetone. Next, a urethane primer (product name: Sinkbond Primer U-100, manufactured by Sekisui Chemical Co., Ltd.) was applied to the bottom and sides of the rails and allowed to cure until the tackiness disappeared. Next, an adhesive mixture of vinyl ester adhesive (product name: Adhesive Primer V200 (main component), manufactured by Sekisui Chemical Co., Ltd.) and a hardener (product name: Mepox D, manufactured by Sekisui Chemical Co., Ltd.) was applied to the bottom and sides of the rail via a urethane primer. Next, fiber-reinforced prepreg sheets were attached to the vinyl ester adhesive-coated surfaces of the bottom and sides of the rail. When attaching the fiber-reinforced prepreg sheets, they were pressed against the rail to push out the vinyl ester adhesive between the rail and the prepreg sheet along with any air bubbles, ensuring no air bubbles remained between the rail and the prepreg sheet. The fiber-reinforced prepreg sheet contained glass mat and vinyl ester resin, with a basis weight of 600 g / m². 2 A sheet measuring 1.5 mm thick, 400 mm long, and 400 mm wide was used. The presence or absence of lifting or peeling of the fiber-reinforced prepreg sheet was visually inspected immediately after (0 minutes) of attaching the fiber-reinforced prepreg sheet to the rail, 5 minutes after attaching the fiber-reinforced prepreg sheet to the rail, and 10 minutes after attaching the fiber-reinforced prepreg sheet to the rail. The results are shown in Table 1. In addition, the time required to attach the fiber-reinforced prepreg sheet to the rail (construction time) was measured. The results are shown in Table 2.

[0060] [Example 2] Except for using a fiber-reinforced prepreg sheet with a thickness of 3.0 mm, the procedure was the same as in Example 1, and the fiber-reinforced prepreg sheet was attached to the vinyl ester adhesive-coated surfaces at the bottom and sides of the rail. In the same manner as in Example 1, the presence or absence of lifting or peeling of the fiber-reinforced prepreg sheet was visually inspected. The results are shown in Table 1.

[0061] [Example 3] Except for using a fiber-reinforced prepreg sheet with a thickness of 4.5 mm, the procedure was the same as in Example 1, and the fiber-reinforced prepreg sheet was attached to the vinyl ester adhesive-coated surfaces at the bottom and sides of the rail. In the same manner as in Example 1, the presence or absence of lifting or peeling of the fiber-reinforced prepreg sheet was visually inspected. The results are shown in Table 1.

[0062] [Comparative Example 1] The surfaces of the rail's underside, the bottom of the rail, and the top of the rail's bottom were prepared with sandpaper to remove rust. Next, I wiped off the rust particles from the surface of the rails with a cloth soaked in acetone. Next, a mixture of vinyl ester primer (product name: Lipoxy CP-819B, manufactured by Showa Denko Corporation) and hardener (product name: Percadox B-40ES, manufactured by Nippon Special Paint Co., Ltd.) was applied to the bottom and sides of the rails, and cured until the tackiness disappeared. Next, a mixture of vinyl ester resin (product name: Lipoxy R-804, manufactured by Showa Denko Corporation) and a hardening agent (product name: Kayamec M, manufactured by Kayaku Nurion Co., Ltd.) was applied as a reinforcing layer. Subsequently, a 400mm x 400mm glass mat (product name: MC450A, manufactured by Nitto Boseki Co., Ltd.) was attached to the reinforcing layer. After that, the glass mat was impregnated with the vinyl ester resin mentioned above, and then degassed. Next, a mixture of vinyl ester resin (product name: Lipoxy R-804B, Showa Denko Corporation) and a hardener (product name: Kayamec M, manufactured by Kayaku Nurion Co., Ltd.) was applied as a topcoat. The rail surface was treated as described above. The time required to attach the glass mat to the rail (installation time) was measured. The results are shown in Table 2.

[0063] [Table 1]

[0064] The results in Table 1 confirm that in Examples 1 and 2, no lifting or peeling of the fiber-reinforced prepreg sheet occurred even 10 minutes after application.

[0065] [Table 2]

[0066] The results in Table 2 show that the prepreg sheet construction method using fiber-reinforced prepreg sheets in Example 1 can be completed in 1 hour, while the hand lay-up method using glass mats in Comparative Example 1 can be completed in 6 hours.

[0067] [Example 4] [Evaluation of the flammability of fiber-reinforced prepreg sheets] The flammability of fiber-reinforced prepreg sheets was evaluated using the following method. On one side of a steel plate (SS400, 4.5mm thick, 257mm long, 182mm wide), apply urethane primer (product name: Sinkbond Primer U-100, manufactured by Sekisui Chemical Co., Ltd.) at a rate of 0.15 kg / m². 2 The coating was applied and allowed to cure until the tackiness (stickiness) disappeared. Next, a mixture of vinyl ester adhesive (product name: Adhesive Primer V200 (main component), manufactured by Sekisui Chemical Co., Ltd.) and hardener (product name: Mepox D, manufactured by Sekisui Chemical Co., Ltd.) is applied to one side of the steel plate via a urethane primer at a rate of 0.15 kg / m². 2 It was applied. Next, a fiber-reinforced prepreg sheet was attached to one side of the steel plate where vinyl ester adhesive had been applied. When attaching the fiber-reinforced prepreg sheet, the sheet was pressed against the steel plate to push out the vinyl ester adhesive between the rail and the fiber-reinforced prepreg sheet along with any air bubbles, ensuring that no air bubbles remained between the rail and the fiber-reinforced prepreg sheet. The fiber-reinforced prepreg sheet contained glass mat and vinyl ester resin, with a basis weight of 600 g / m². 2 A sheet measuring 1.6 mm thick, 257 mm long, and 182 mm wide was used. The flammability of the fiber-reinforced prepreg sheet was evaluated through the above-mentioned flammability test for railway vehicles. The temperature in the test room was set to 21°C and the humidity to 60%. The burning time of the alcohol was set to 1 minute and 48 seconds. The results are shown in Table 3. The criteria for determining flammability are shown in Table 4.

[0068] [Table 3]

[0069] [Table 4]

[0070] The following are important points to consider when making your decision. Based on the combustion results, the grade of the test material will be determined according to the evaluation criteria, with the lowest grade corresponding to the evaluation of all elements during and after the combustion of alcohol being used. In this case, if abnormal smoke is emitted, the grade will be lowered by one level according to the remarks. Abnormal smoke emission refers to a condition where flammable gas generated inside the test specimen due to heating is ejected, ignited, and the flames continuously erupt almost perpendicularly to the surface of the specimen for several seconds. If the flames are weak and only momentarily below perpendicular to the surface, it is considered "weak abnormal smoke emission" and does not affect the evaluation. Regarding the non-flammable smoke, "little" refers to smoke about the same amount as cigarette smoke, which dissipates without exceeding the top of the test specimen. In the smoke section, "a lot" refers to smoke that exceeds the top of the test specimen. The intensity of the flame is judged by whether the flame rising horizontally above the top of the test specimen clearly exceeds the line of sight. If this occurs for a short period of about one second, it is treated as "momentarily exceeding" the line of sight, and this does not result in a lower grade. In the section on carbonization, discoloration refers to slight, superficial discoloration that does not result in carbonization, while carbonization refers to a clear alteration of the material.

[0071] Based on the results shown in Table 3, the fiber-reinforced prepreg sheet was determined to be non-combustible.

[0072] [Example 5] [Evaluation of the barrier properties of fiber-reinforced prepreg sheets] The barrier properties of fiber-reinforced prepreg sheets were evaluated using the following method. Example 5 will be explained using Figure 5. In Figure 5, the urethane primer and vinyl ester adhesive are not shown. On one side 210a of a steel plate (SS400, 4.5mm thick, 220mm long, 15mm wide) 210, apply 0.15 kg / m² of urethane primer (product name: Sinkbond Primer U-100, manufactured by Sekisui Chemical Co., Ltd.). 2 The coating was applied and allowed to cure until the tackiness (stickiness) disappeared. Next, a mixture of vinyl ester adhesive (product name: Adhesive Primer V200 (main component), manufactured by Sekisui Chemical Co., Ltd.) and hardener (product name: Mepox D, manufactured by Sekisui Chemical Co., Ltd.) is applied to one side 210a of the steel plate 210 via a urethane primer at a rate of 0.15 kg / m². 2 It was applied. Next, a fiber-reinforced prepreg sheet 220 was attached to one side 210a of the steel plate 210 where vinyl ester adhesive had been applied. Specifically, a first fiber-reinforced prepreg sheet 221 and a second fiber-reinforced prepreg sheet 222 were used as the fiber-reinforced prepreg sheet 220, with one end 221a of the first fiber-reinforced prepreg sheet 221 overlapping one end 222a of the second fiber-reinforced prepreg sheet 222 in the longitudinal direction. The overlapping length (W shown in Figure 5) between one end 221a of the first fiber-reinforced prepreg sheet 221 and one end 222a of the second fiber-reinforced prepreg sheet 222 in the longitudinal direction was 10 mm. As shown in Figure 6, the fiber-reinforced prepreg sheet 220 was positioned below, and both ends of the laminate, including the steel plate 210 and the fiber-reinforced prepreg sheet 220, were supported by columnar support points 311 and 312 so as to be in contact with the fiber-reinforced prepreg sheet 220. In this state, a universal testing machine (device name: Tensilon, manufactured by A&D Co., Ltd.) was used to apply a force downward in the thickness direction of the laminate to the center of the laminate using a pressure member 320, and the bending strength of the displacement at which the laminate peeled off from the base material was measured. The displacement at which the bending strength decreased was used as the displacement at which the laminate peeled off from the base material. The results are shown in Table 5.

[0073] [Example 6] [Evaluation of the sustained barrier properties of fiber-reinforced prepreg sheets] Except for setting the overlap length W between one longitudinal end 221a of the first fiber-reinforced prepreg sheet 221 and one longitudinal end 222a of the second fiber-reinforced prepreg sheet 222 to 25 mm, the bending strength of the laminate was measured in the same manner as in Example 5, at which point it peeled off from the base material. The results are shown in Table 5.

[0074] [Example 7] [Evaluation of the sustained barrier properties of fiber-reinforced prepreg sheets] Except for setting the overlap length W between one longitudinal end 221a of the first fiber-reinforced prepreg sheet 221 and one longitudinal end 222a of the second fiber-reinforced prepreg sheet 222 to 50 mm, the bending strength of the laminate was measured in the same manner as in Example 5, at which point it peeled off from the base material. The results are shown in Table 5.

[0075] [Example 8] [Evaluation of the sustained barrier properties of fiber-reinforced prepreg sheets] Except for setting the overlapping length W between one longitudinal end 221a of the first fiber-reinforced prepreg sheet 221 and one longitudinal end 222a of the second fiber-reinforced prepreg sheet 222 to 75 mm, the bending strength of the laminate was measured in the same manner as in Example 5, at which point it peeled off from the base material. The results are shown in Table 5.

[0076] [Example 9] [Evaluation of the sustained barrier properties of fiber-reinforced prepreg sheets] As shown in Figure 7, the bending strength of the laminate was measured in the same manner as in Example 5, except that one end face 221b in the longitudinal direction of the first fiber-reinforced prepreg sheet 221 and one end face 222b in the longitudinal direction of the second fiber-reinforced prepreg sheet 222 were butted together. The results are shown in Table 5.

[0077] [Example 10] [Evaluation of the sustained barrier properties of fiber-reinforced prepreg sheets] As shown in Figure 8, the bending strength of the laminate was measured in the same manner as in Example 5, except that a single fiber-reinforced prepreg sheet 220 was attached to one surface 210a of the steel plate 210. The results are shown in Table 5.

[0078] [Table 5]

[0079] As shown in Table 5, the durability of the fiber-reinforced prepreg sheet 220 was improved in Examples 5 to 8 compared to Examples 9 and 10. [Explanation of Symbols]

[0080] 10 rails 11 Head 12 Abdomen 13 Bottom 20 Fiber-reinforced prepreg sheets 30. Rail repair structure

Claims

1. A repair structure provided on a rail, The rail has a fiber-reinforced prepreg sheet covering both sides of the bottom and the body of the rail that is continuous with the bottom, The aforementioned fiber-reinforced prepreg sheet has a basis weight of 450 g / m². ２ More than 1050g / m ２ The following: The aforementioned fiber-reinforced prepreg sheet includes glass fibers and a curable resin. The aforementioned curable resin is a light-curing resin, in a rail repair structure.

2. The rail repair structure according to claim 1, wherein the thickness of the fiber-reinforced prepreg sheet is 3.0 mm or less.

3. The aforementioned fiber-reinforced prepreg sheet has flame retardancy equal to or better than that determined by a flammability test for railway vehicles, as described in claim 1 or 2, for the rail repair structure.

4. A rail repair structure according to any one of claims 1 to 3, wherein a plurality of the fiber-reinforced prepreg sheets partially overlap each other in the longitudinal direction of the rail.

5. The system comprises a rail and a fiber-reinforced prepreg sheet covering both sides of the bottom of the rail and the body of the rail that is continuous with the bottom, The aforementioned fiber-reinforced prepreg sheet has a basis weight of 450 g / m². ２ More than 1050g / m ２ The following: The aforementioned fiber-reinforced prepreg sheet includes glass fibers and a curable resin. The aforementioned curable resin is a light-curing resin, and the rail has a repair structure.

6. The rail with repair structure according to claim 5, wherein the thickness of the fiber-reinforced prepreg sheet is 3.0 mm or less.

7. The aforementioned fiber-reinforced prepreg sheet has flame retardancy equal to or better than that determined by a flammability test for railway vehicles, as described in claim 5 or 6, for a rail with a repair structure.

8. A rail with a repair structure according to any one of claims 5 to 7, wherein multiple sheets of the fiber-reinforced prepreg sheet partially overlap each other in the longitudinal direction of the rail.

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