Method for repairing resin structure

Abstract

This method for repairing a resin structure includes: a pretreatment agent application step for applying a pretreatment agent onto a surface (12) to be repaired, which includes a repair section (11), of a resin structure (10) made of dicyclopentadiene resin in order to suppress deterioration of adhesive performance; and a repair material bonding step for bonding a repair material (30) made of fiber-reinforced plastic to the surface (12) to be repaired of the resin structure (10) after the pretreatment agent application step.

Description

Method for Repairing Resin Structure

[0001] The present disclosure relates to a method for repairing a resin structure.

[0002] Conventionally, as disclosed in Patent Document 1 below, a repair method for repairing corrosion and deterioration of a fiber-reinforced plastic storage tank is well-known. This repair method aims to improve adhesion, and includes a polishing step, a solvent application step, a scratching step, a cleaning step, and an adhesion step on the surface portion of the storage tank. In the adhesion step, a repair material, which is the adherend, is finally adhered to the surface portion of the storage tank.

[0003] Japanese Patent Application Laid-Open No. 2018-178376

[0004] Generally, a resin structure such as a storage tank is composed of fiber-reinforced plastic, but dicyclopentadiene resin has attracted attention as an alternative to fiber-reinforced plastic. Dicyclopentadiene resin has an advantage of being less likely to crack compared to fiber-reinforced plastic. Dicyclopentadiene resin can be suitably used for large resin structures such as, for example, the tank body of a septic tank or a storage tank, and the body of a large vehicle.

[0005] On the other hand, it is known that a resin structure made of dicyclopentadiene resin has poor adhesion performance of the repair material and is difficult to adhere compared to one made of fiber-reinforced plastic. Therefore, it is difficult to directly adopt the repair method of Patent Document 1 for repairing a resin structure made of dicyclopentadiene resin. Thus, it has been considered to adopt a repair method in which a surface modification treatment such as plasma surface treatment is performed in advance on the repair location of the resin structure and then the repair material is adhered.

[0006] However, even with the above surface modification treatment, while some improvement in adhesive performance can be expected, it is difficult to satisfy the desired adhesive strength of the repair material to the resin structure. Therefore, for example, a repair method can be adopted in which a backing plate is made to match the shape of the repair area, silicone or adhesive is placed between the backing plate and the repair area, and the backing plate is fixed with fixing members such as rivets or bolts and nuts. This repair method has the problem of being time-consuming because it requires the backing plate to be made in advance and fixing members are necessary. In addition, surface modification treatments such as plasma surface treatment are disadvantageous in that they require large-scale processing equipment.

[0007] This disclosure has been made in view of the above issues and aims to provide a simple method for repairing resin structures made of dicyclopentadiene resin.

[0008] One aspect of the present disclosure is a method for repairing a resin structure made of dicyclopentadiene resin, comprising: a pretreatment agent application step of applying a pretreatment agent to the surface to be repaired, including the repair area of ​​the resin structure, for suppressing a decrease in adhesive performance; and a repair material bonding step of bonding a repair material made of fiber-reinforced plastic to the surface to be repaired of the resin structure after the pretreatment agent application step.

[0009] In the repair method described above, first, in the pretreatment agent application step, a pretreatment agent is applied to the surface of the resin structure made of dicyclopentadiene resin, including the area to be repaired, in order to suppress the deterioration of adhesive performance. Then, in the repair material bonding step, a repair material made of fiber-reinforced plastic is bonded to the surface of the resin structure to be repaired. As a result, the repair material is bonded to the resin structure in a state where the deterioration of adhesive performance is suppressed by the effect of the pretreatment agent, and the repair area is covered with this repair material.

[0010] This repair method allows for good adhesion of the repair material to the surface of the resin structure, even to difficult-to-bond materials such as resin structures made of dicyclopentadiene resin, by pre-applying a pre-treatment agent to the surface to be repaired. Furthermore, it eliminates the need for large-scale equipment required for surface modification treatments such as plasma surface treatment, and allows for simple repair of the repaired area of ​​the resin structure.

[0011] As described above, according to the above embodiment, a simple method for repairing a resin structure made of dicyclopentadiene resin can be provided.

[0012] The above-mentioned objectives and other objectives, features and advantages of this disclosure will become clearer from the following detailed description, which will be explained with reference to the attached drawings. The drawings are as follows: Figure 1 is a diagram showing the cross-sectional structure of a resin structure according to Embodiment 1; Figure 2 is a flowchart showing the flow of the repair method for the resin structure according to Embodiment 1; Figure 3 is a view from inside the tank of the repair area of ​​the resin structure in Figure 1 before the repair material is bonded; Figure 4 is a view from inside the tank of the resin structure in Figure 3 after the surface to be repaired has been polished; Figure 5 is a view from inside the tank of the resin structure in Figure 4 after a halogen-based surface modifier has been applied to the surface to be repaired; and Figure 6 is a view from inside the tank of the resin structure in Figure 5 after an adhesive primer has been applied to the surface to be repaired. Figure 7 is a view from the side, showing the state after the repair material has been bonded to the surface of the resin structure to be repaired in Figure 6, as seen from inside the tank; Figure 8 is a plan view of the molded body in the evaluation test; Figure 9 is a view of the cross section along line IX-IX in Figure 8; Figure 10 is a diagram showing the classification of the workpieces for evaluation; Figure 11 is a diagram showing the classification of the processing conditions; Figure 12 is a plan view showing the tensile measurement of the workpieces for evaluation; Figure 13 is a diagram showing the evaluation results for the workpieces for evaluation in the example and comparative example; and Figure 14 is a flowchart showing the flow of the resin structure repair method in Embodiment 2.

[0013] Preferred embodiments of the above-described aspects are described below.

[0014] In the above-described method for repairing a resin structure, in the pretreatment agent application step, it is preferable to use a halogen-based surface modifier and a carbon-containing adhesive primer as pretreatment agents, and to apply the halogen-based surface modifier to the surface to be repaired, followed by the adhesive primer. The halogen-based surface modifier has the function of suppressing the release of unreacted monomers that contribute to a decrease in adhesive performance. The carbon-containing adhesive primer, in addition to functioning as an adhesive for the repair material, also has the function of shielding unreacted monomers that contribute to a decrease in adhesive performance with carbon. With this repair method, by sequentially applying the halogen-based surface modifier and the carbon-containing adhesive primer to the surface to be repaired of the resin structure, it becomes possible to reliably adhere the repair material to the surface to be repaired of the resin structure.

[0015] In the above-described method for repairing a resin structure, it is preferable to use a chlorine-based halogenated surface modifier containing halogenated isocyanuric acid in the pretreatment agent application step. Halogenated isocyanuric acid is highly effective in suppressing the release of unreacted monomers that contribute to a decrease in adhesive performance. With this repair method, by using a halogenated surface modifier containing halogenated isocyanuric acid, it is possible to increase the adhesive strength of the repair material to the repair target surface of the resin structure.

[0016] The above-described method for repairing a resin structure preferably includes a post-treatment step that performs a post-treatment to increase the adhesive strength of the repair material to the resin structure compared to immediately after the bonding process. With this repair method, by performing the post-treatment step following the repair material bonding step, it becomes possible to improve the adhesive strength of the repair material to the surface of the resin structure to be repaired to a desired level.

[0017] In the above-described method for repairing a resin structure, when a resin structure made of dicyclopentadiene resin is used as the first resin structure and a resin structure made of fiber-reinforced plastic is used as the second resin structure, it is preferable to use post-treatment conditions in the post-treatment step such that the adhesive strength of the repair material to the first resin structure exceeds the adhesive strength of the repair material to the second resin structure. This repair method makes it possible to obtain an adhesive strength that exceeds that of a resin structure made of fiber-reinforced plastic.

[0018] In the above-described method for repairing a resin structure, the resin structure is the tank body of a septic tank or storage tank used for buried purposes, and it is preferable that in the pretreatment agent application step, the pretreatment agent is applied to the surface to be repaired from inside the tank body, and in the repair material bonding step, the repair material is bonded to the surface to be repaired from inside the tank body. With this repair method, if the tank body of a septic tank or storage tank used for buried purposes is a resin structure made of dicyclopentadiene resin, it becomes possible for an operator to enter the resin structure and repair the target area with relatively simple work.

[0019] The following describes specific examples of the resin structure repair method according to the above-described embodiment, with reference to the drawings.

[0020] (Embodiment 1) 1. Resin structure 10 As shown in Figure 1, the resin structure 10 used in Embodiment 1 is the tank body of a septic tank or storage tank. This resin structure 10 has a manhole 10a and an internal space 10b. This resin structure 10 is generally used by being buried underground (it may also be used by being installed above ground if necessary). The manhole 10a is the part of the resin structure 10 that allows workers to enter the internal space 10b, and is basically used when maintaining and inspecting the resin structure 10. The internal space 10b is a space in which inflowing water from the outside is temporarily stored.

[0021] The resin structure 10 is made of dicyclopentadiene resin. This resin structure 10 has the physical property of being less prone to cracking compared to those made of fiber-reinforced plastic. The resin structure 10 is molded using a method called "RIM (Reaction Injection Molding) molding". Although a detailed explanation will be omitted, RIM molding is a well-known injection molding method in which material is injected into a sealed mold. In general injection molding, materials that need to be melted by heat and injected into the mold at high pressure are used, whereas in RIM molding, materials that need to be reacted by mixing and collision are used. For this reason, the raw material can be injected into the mold at a lower pressure and molded at a lower pressure compared to injection molding. Therefore, RIM molding has the advantage that it can be made using inexpensive equipment and the injection time can be extended by arbitrarily adjusting the reaction time, making it easier to mold large products.

[0022] Repair points 11 may be formed in the resin structure 10 (see Figure 3). Although dicyclopentadiene resin is inherently a crack-resistant material, cracks may occur in the repair points 11 due to various reasons. Also, although dicyclopentadiene resin is a material that does not easily deteriorate over time, deterioration may occur in the repair points 11. When repairing such repair points 11, it is required to keep maintenance costs low.

[0023] Attempting to repair the resin structure 10 from the outside would require removing backfill soil, upper slab concrete, etc., which would be extremely time-consuming and result in high maintenance costs. Therefore, to keep maintenance costs low, it is effective to perform repair work on-site by having a worker enter the internal space 10b through the manhole 10a of the resin structure 10 and carry out the repairs in a tank. This repair work is made possible by having a worker adhere the repair material 30 to the repair target surface 12, including the repair area 11 of the resin structure 10, from inside the tank (see Figure 1).

[0024] 2. Repair Material 30 In this embodiment, the repair material 30 is a sheet-like overlay resin material having a generally constant thickness. This repair material 30 is made of fiber-reinforced plastic in which unsaturated polyester resin is reinforced with glass fibers. This type of fiber-reinforced plastic is generally called "FRP (Fiber-Reinforced Plastics)". If necessary, fiber-reinforced plastics that combine fibers such as glass fibers or carbon fibers with reactive resins or thermoplastic resins such as unsaturated polyester resin or epoxy resin may be used. The planar shape of the repair material 30 is appropriately changed according to the shape of the repair area 11.

[0025] 3. Repair Method The repair method for the fiber structure of Embodiment 1 (hereinafter simply referred to as the "repair method") will be described with reference to Figures 1 to 7. This repair method is made possible by sequentially executing each step from step S101 to step S104 in Figure 2. If necessary, one or more steps may be added to these steps, or at least one step may be divided into multiple steps.

[0026] 3-1. Preparation Step S101 in Diagram 2 is a preparation step for the pretreatment agent application step. In the preparation step, the repair target surface 12 (see Figure 4) of the resin structure 10 and its surroundings are washed with water. Then, the repair target surface 12 is polished using abrasive means such as sandpaper or a grinder wheel. This polishing process is also called "sanding". Furthermore, the repair target surface 12 after polishing is degreased with a solvent such as acetone.

[0027] 3-2. Pretreatment Agent Application Process Step S102 in Figure 2 is the pretreatment agent application process. In the pretreatment agent application process, a pretreatment agent 20 (see Figure 1) is applied to the repair target surface 12 of the resin structure 10 to suppress the decrease in adhesive performance. In this embodiment, with good ventilation maintained in the tank, the worker applies the pretreatment agent 20 to the repair target surface 12 of the resin structure 10 from inside the tank. In this embodiment, two types of pretreatment agents 20 are used: a halogen-based surface modifier 20A and an adhesive primer 20B. First, the halogen-based surface modifier 20A is applied to the repair target surface 12 of the resin structure 10 and then dried for a predetermined time. Subsequently, the adhesive primer 20B is applied to the repair target surface 12 and then dried for a predetermined time. Note that, if necessary, the halogen-based surface modifier 20A may be changed to another surface modifier that has the same function as the halogen-based surface modifier 20A.

[0028] 3-3. Repair Material Bonding Process Step S103 in Figure 2 is the repair material bonding process. In the repair material bonding process, after the pretreatment agent application process, the repair material 30 is bonded to the repair target surface 12 of the resin structure 10. In this embodiment, with good ventilation maintained inside the tank, the worker bonds the repair material 30 to the repair target surface 12 of the resin structure 10 from inside the tank. The process of bonding the repair material 30 is also called "overlay". According to this repair material bonding process, the repair area 11 of the resin structure 10 is sealed with the repair material 30.

[0029] 3-4. Post-treatment process Step S104 in Diagram 2 is a post-treatment process performed after the completion of the repair material bonding process. In the post-treatment process, post-treatment is performed to increase the adhesive strength of the repair material 30 to the resin structure 10 compared to immediately after the bonding process. For example, post-treatment conditions such as leaving the bonded area at room temperature for a long period of time (condition B described later) or post-treatment conditions such as maintaining the bonded area heated to a predetermined temperature for a predetermined time (condition C described later) can be adopted. Heating of the bonded area can be performed, for example, by introducing a heating means such as a heater (not shown) into the tank of the resin structure 10. According to this post-treatment process, the adhesive strength is increased by the thermosetting action of the bonded area. This post-treatment is also called "after-cure".

[0030] 4. Halogenated Surface Modifier 20A The halogenated surface modifier 20A used in this embodiment is a mixture of halogenated isocyanuric acid and a solvent. This halogenated surface modifier 20A has the function of suppressing the release of unreacted monomers that contribute to a decrease in adhesive performance.

[0031] As an example of halogenated isocyanuric acid, chlorine-based trichloroisocyanuric acid can be used. However, the type and number of halogen substituents are not limited to this. For example, the chlorine in trichloroisocyanuric acid may be replaced with fluorine or bromine. Also, the number of halogen substituents may be reduced from three to two. Ethyl acetate and toluene can be used as examples of solvents. Alternatively, similar solvents such as butyl acetate or xylene may be used in addition to these.

[0032] For example, when using trichloroisocyanuric acid, the volume ratio of trichloroisocyanuric acid in the halogenated surface modifier 20A can be set to, for example, about 3%. This volume ratio is not particularly limited and is preferably set appropriately depending on the combination of halogenated isocyanuric acid and solvent.

[0033] 5. Adhesive Primer 20B The adhesive primer 20B is a primer that is also used as an adhesive for the repair material 30. While general primers assist the function of adhesives, the adhesive primer 20B differs in that the primer itself has an adhesive-like function. In this embodiment, the adhesive primer 20B is a primer for urethane-based adhesives. Alternatively, a primer for adhesives other than urethane-based adhesives may be used. For example, urethane-based adhesives contain ethyl acetate, toluene, carbon black, butyl acetate, and chlorobenzene. Thus, the adhesive primer 20B containing carbon performs a function not only as an adhesive but also as a shielding against unreacted monomers that contribute to a decrease in adhesive performance. In other words, this adhesive primer 20B performs a function of suppressing a decrease in adhesive performance, similar to the halogen-based surface modifier 20A.

[0034] Therefore, the adhesive primer 20B, in cooperation with the halogen-based surface modifier 20A, exhibits the function of increasing the adhesive strength of the repair material 30 to the repair target surface 12 of the resin structure 10. The adhesive primer 20B may contain carbon or it may not contain carbon. If the desired effect of suppressing the release of unreacted monomers (desired adhesive strength) can be obtained with the halogen-based surface modifier 20A alone, an adhesive primer 20B that does not contain carbon can be used.

[0035] 6. Evaluation Test The inventor conducted the following evaluation test to confirm the effectiveness of the repair method described above.

[0036] 6-1. Preparation of evaluation workpieces As shown in Figures 8 and 9, for the evaluation test, two flat test pieces 41 corresponding to the resin structure 10 and a sheet-like test piece 42 corresponding to the repair material 30 were prepared. Then, the same procedure as the repair method in Figure 2 was carried out. In these drawings, the thickness direction of the test piece 41 is denoted by arrow X, and the width direction and depth direction, which are perpendicular to the thickness direction X and mutually perpendicular, are denoted by arrows Y and Z, respectively.

[0037] First, as a process corresponding to step S101 (preparation step) in Figure 2, each surface 41a of the two test pieces 41 was polished, with each surface 41a designated as the repair target surface. Furthermore, each surface 41a was degreased with a solvent. After that, with the two test pieces 41 butted together in the width direction Y, masking tape 43 was applied to the two test pieces 41 to seal the gap between them. This masking tape 43 was used to prevent the pretreatment agent 20 from entering the gap between the two test pieces 41.

[0038] Next, as a process corresponding to step S102 (pretreatment agent application step) in Figure 2, halogen-based surface modifier 20A was first applied to each surface 41a of the two test pieces 41, and then dried for a predetermined time (for example, about 10 minutes). Subsequently, adhesive primer 20B was applied to each surface 41a of the two test pieces 41, and then dried for a predetermined time (for example, about 10 minutes).

[0039] Next, as a process corresponding to step S103 (repair material bonding process) in Figure 2, test piece 42 was bonded to each surface 41a of the two test pieces 41 by overlapping them in the thickness direction X. The bonding function of the bonding primer 20B was utilized for bonding test piece 41 and test piece 42. In this way, a molded body W, which is an adhesive body formed by bonding test piece 42 to the two test pieces 41, was produced.

[0040] Furthermore, by performing a post-processing step corresponding to step S104 (post-processing step) in Figure 2 on the molded body W, for example, the evaluation workpiece W1 shown in Figure 12 was produced. In this embodiment, as shown in Figure 10, six types of evaluation workpieces W1 to W6, including the evaluation workpiece W1, were produced.

[0041] 6-2. Each of the tensile measurement evaluation workpieces W1 to W6 was sequentially set in a known universal testing machine (not shown), and tensile measurements were performed by pulling the two test pieces 41 of the evaluation workpiece apart from each other in the width direction Y at a constant speed. Figure 12 shows the tensile measurement of one evaluation workpiece W1. The stress measured at this time was defined as the adhesive strength S of the bond between test piece 41 and test piece 42 in the evaluation workpiece W1.

[0042] 6-3. Classification of Evaluation Workpieces The three evaluation workpieces W1 to W3 were all prepared as examples and consist of dicyclopentadiene resin. In contrast, the remaining three evaluation workpieces W3 to W6 were all prepared as comparative examples and consist of fiber-reinforced plastic. Evaluation workpieces W1 and W4 were subjected to condition A, which does not involve a post-treatment process. In contrast, evaluation workpieces W2 and W5 were subjected to condition B, which involves a post-treatment process, and evaluation workpieces W3 and W6 were subjected to condition C, which involves a post-treatment process.

[0043] 6-4. Classification of Processing Conditions As shown in the classification diagram of processing conditions in Fig. 11, Condition A is a processing condition in which the standing time t1 from immediately after the adhesion treatment of the test piece 41 and the test piece 42 to the above-described tensile test is set to a short time of about 2 hours, for example. Therefore, Condition A does not substantially correspond to a post-treatment condition. Condition B is a processing condition in which the test piece 41 and the test piece 42 are left at room temperature for d days from immediately after the adhesion treatment to the above-described tensile test, and corresponds to a post-treatment condition. In this Condition B, the standing time of the evaluation work is significantly longer than that of Condition A. Condition C is a processing condition in which an after-cure time for maintaining the temperature condition of T [°C] for t2 hours is provided from immediately after the adhesion treatment of the test piece 41 and the test piece 42, and then left at room temperature for d days until the above-described tensile test, and corresponds to a post-treatment condition.

[0044] Note that the specific numerical values in each processing condition in Fig. 11 are not particularly limited, but as an example, t1 = 2, t2 = 6, d = 4, and T = 75 can be set. Other numerical values may be appropriately adopted as needed.

[0045] 6-5. Evaluation Results The evaluation results in Fig. 13 are about the relationship between the processing conditions and the adhesive strength. In these evaluation results, the plots indicated by the symbol "〇" are for the three evaluation works W1 to W3 of the example (in the case of the first resin structure 10 using a dicyclopentadiene resin). Also, the plots indicated by the symbol "△" are for the three evaluation works W4 to W6 of the comparative example (in the case of the second resin structure 10' using a fiber-reinforced plastic).

[0046] In the case of the embodiment, the adhesive strength S of the evaluation work W2 (condition B) exceeded that of the evaluation work W1 (condition A), and it was confirmed that the adhesive strength S of the evaluation work W3 (condition C) exceeded that of the evaluation work W2 (condition B). Similarly, in the case of the comparative example, the adhesive strength S of the evaluation work W5 (condition B) exceeded that of the evaluation work W4 (condition A), and it was confirmed that the adhesive strength S of the evaluation work W6 (condition C) exceeded that of the evaluation work W5 (condition B). Based on these results, in order to increase the adhesive strength S of the adhesive part, it is preferable to adopt the post-treatment conditions of condition B, and it can be evaluated that the post-treatment conditions of condition C are superior to those of condition B.

[0047] When comparing the embodiment and the comparative example, it was confirmed that the adhesive strength S of the evaluation work W5 (condition B) of the comparative example was lower than that of the evaluation work W1 (condition A) of the embodiment. Also, it was confirmed that the adhesive strength S of the evaluation work W6 (condition C) of the comparative example exceeded that of the evaluation work W1 (condition A) of the embodiment and was lower than that of the evaluation work W2 (condition B) of the embodiment. Based on these results, if the adhesive strength S of the evaluation work W6 of the comparative example is used as the management reference value Th and post-treatment conditions (for example, condition B or condition C) that exceed the management reference value Th are adopted, it is possible to obtain a higher adhesive strength S than in the comparative example.

[0048] 7. Operational Effects According to the above-described Embodiment 1, the following operational effects are achieved

[0049] In the repair method of Embodiment 1, first, in the pretreatment agent application step, a pretreatment agent 20 for suppressing a decrease in adhesive performance is applied to a repair target surface 12 including a repair location 11 of a resin structure 10 made of dicyclopentadiene resin. Then, in the repair material adhesion step, a repair material 30 made of fiber-reinforced plastic is adhered to the repair target surface 12 of the resin structure 10. As a result, the repair material 30 is adhered to the resin structure 10 in a state where a decrease in adhesive performance is suppressed by the effect of the pretreatment agent, and the repair location 11 is covered with this repair material 30.

[0050] With this repair method, by pre-applying a pre-treatment agent 20 to the repair target surface 12 of the resin structure 10 to suppress the deterioration of adhesive performance, it becomes possible to properly adhere the repair material 30 to the repair target surface 12, even for resin structures 10 made of dicyclopentadiene resin, which are difficult to adhere to. Furthermore, it eliminates the need for large-scale equipment required for surface modification treatments such as plasma surface treatment, and allows for simple repair of the repair area 11 of the resin structure 10.

[0051] Therefore, according to the above-described embodiment 1, a simple method for repairing a resin structure 10 made of dicyclopentadiene resin can be provided.

[0052] Furthermore, according to the repair method of Embodiment 1, by sequentially applying a halogen-based surface modifier 20A and an adhesive primer 20B containing carbon to the repair target surface 12 of the resin structure 10, it becomes possible to reliably adhere the repair material 30 to the repair target surface 12 of the resin structure 10.

[0053] Furthermore, according to the repair method of Embodiment 1, by using a halogenated surface modifier 20A containing halogenated isocyanuric acid, it is possible to increase the adhesive strength S of the repair material 30 to the repair target surface 12 of the resin structure 10.

[0054] Furthermore, according to the repair method of Embodiment 1, by performing a post-treatment step to increase the adhesive strength S following the repair material bonding step, it becomes possible to improve the adhesive strength S of the repair material 30 to the repair target surface 12 of the resin structure 10 to a desired level.

[0055] Furthermore, according to the repair method of Embodiment 1, it becomes possible to obtain an adhesive strength S for a resin structure made of dicyclopentadiene resin (i.e., the first resin structure 10) that is greater than that for a resin structure made of fiber-reinforced plastic (i.e., the second resin structure 10').

[0056] Furthermore, according to the repair method of Embodiment 1, if the tank body of the septic tank or storage tank is a resin structure 10 made of dicyclopentadiene resin, it becomes possible for an operator to enter the resin structure 10 and repair the repair area 11 with relatively simple work.

[0057] Hereinafter, other embodiments related to Embodiment 1 described above will be explained with reference to the drawings. In the other embodiments, the same reference numerals are used as in Embodiment 1 described above, and the explanation of such identical elements will be omitted.

[0058] (Embodiment 2) The repair method of Embodiment 2 is made possible by sequentially executing each step from step S201 to step S203 in Figure 14. Steps S201, S202 and S203 are the same as steps S101, S102 and S103 of Embodiment 1 (see Figure 2). In other words, in Embodiment 2, the post-processing step of Embodiment 1 (step S104 in Figure 2) is omitted.

[0059] Based on the evaluation results in Figure 13, it was confirmed that even with the evaluation workpiece W1 (Condition A) of the embodiment, that is, without performing any post-treatment on the molded body W, a higher adhesive strength S can be obtained than with the evaluation workpiece W5 (Condition B) of the comparative example. Therefore, in Embodiment 2, the post-treatment step is omitted based on these evaluation results.

[0060] According to Embodiment 2, by omitting the post-processing step, it becomes possible to reduce the time required for repairing the resin structure 10.

[0061] This disclosure is described in accordance with the embodiments described above, but it is understood that this disclosure is not limited to such forms or structures. This disclosure also includes various modifications and variations within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and idea of ​​this disclosure. For example, the following forms can be implemented by applying each of the forms described above.

[0062] In the above-described embodiment, the example given was the use of a halogen-based surface modifier 20A as a pretreatment agent, but potassium nitrate, potassium permanganate, or the like may be used instead.

[0063] While the above-described examples illustrate repair methods for the tank body of a septic tank or storage tank, the resin structures to be repaired are not limited to the tank body. The methods can also be applied to repair components other than the tank body of a septic tank or storage tank, or to resin structures used in fields other than septic tanks or storage tanks (for example, the body of a large vehicle).

Claims

1. A method for repairing a resin structure made of dicyclopentadiene resin, comprising: a pretreatment agent application step of applying a pretreatment agent to the surface to be repaired, including the repair area of ​​the resin structure, to suppress a decrease in adhesive performance; and a repair material bonding step of bonding a repair material made of fiber-reinforced plastic to the surface to be repaired of the resin structure after the pretreatment agent application step.

2. The method for repairing a resin structure according to claim 1, wherein in the pretreatment agent application step, a halogen-based surface modifier and an adhesive primer containing carbon are used as the pretreatment agent, and the halogen-based surface modifier is applied to the surface to be repaired, and then the adhesive primer is applied.

3. The method for repairing a resin structure according to claim 2, wherein in the pretreatment agent application step, a chlorine-based halogenated surface modifier containing halogenated isocyanuric acid is used.

4. A method for repairing a resin structure according to any one of claims 1 to 3, further comprising a post-treatment step of performing a post-treatment to increase the adhesive strength of the repair material to the resin structure compared to immediately after the bonding treatment.

5. The method for repairing a resin structure according to claim 4, wherein the resin structure made of dicyclopentadiene resin is the first resin structure and the resin structure made of fiber-reinforced plastic is the second resin structure, and in the post-treatment step, post-treatment conditions are used such that the adhesive strength of the repair material to the first resin structure exceeds the adhesive strength of the repair material to the second resin structure.

6. The method for repairing a resin structure according to any one of claims 1 to 3, wherein the resin structure is the tank body of a septic tank or storage tank used for buried purposes, the pretreatment agent is applied to the surface to be repaired from inside the tank body in the pretreatment agent application step, and the repair material is bonded to the surface to be repaired from inside the tank body in the repair material bonding step.

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