Sheet for reinforcing buildings, method for manufacturing sheet for reinforcing buildings, and method for reinforcing buildings

Abstract

The present invention addresses the problem of improving a building reinforcement sheet and a building reinforcement method. Provided is a sheet for building reinforcement, which is formed from a prepreg containing a polyphenylene sulfide resin and carbon fibers, and which has a water contact angle of 50 degrees or less. It is desirable to achieve a tensile strength of 3400 MPa or more and a tensile modulus of elasticity (JSCE-E 541-2013) of 210 GPa to 280 GPa (inclusive), a joint strength of 3400 MPa or more and a test piece breakage (JSCE-E 542-2018) at locations other than an adhesive surface, and an adhesive strength of 1.5 MPa or more and a substrate breakage (JSCE-E 545-2018).

Description

Technical Field

[0001] The present invention relates to a sheet for building reinforcement, a building reinforcement method, and a method for manufacturing a sheet for building reinforcement. The sheet for building reinforcement of the present invention is formed of a sheet obtained by hydrophilizing a prepreg containing an engineering plastic and carbon fiber, and the engineering plastic is formed of one or more selected from polyphenylene sulfide resin, polycarbonate, and polyether ether ketone. The building reinforcement method of the present invention is characterized by using the above-mentioned sheet for building reinforcement. In the method for manufacturing a sheet for building reinforcement of the present invention, the above-mentioned sheet for building reinforcement is fixed to the building surface via an adhesive. Background Art

[0002] It is inevitable that time-dependent aging such as cracks or peeling occurs on the concrete surface in buildings such as bridges or roads. Aging buildings must be repaired regularly. Conventionally, a repair method of protecting the surface of an aging building with a reinforcing material has been adopted.

[0003] In an example of a building reinforcement method described in Patent Document 1, the method includes the following steps: a step of forming an elastic layer on the building surface; and an impregnation step of using a fiber sheet produced by aligning reinforcing fibers in one direction, and by applying an epoxy-based adhesive on the above elastic layer, impregnating epoxy resin into the above fiber sheet and bonding the above fiber sheet to the above elastic layer. In the case of adopting this reinforcement method, in order to impregnate epoxy resin into the fiber sheet at the construction site, careful rolling and curing are required. In the case of laminating multiple fiber sheets, impregnation and bonding operations are required for each formation of a fiber sheet layer. Therefore, there are problems in terms of efficiency with this kind of reinforcement method. Patent Document 1 also describes an example of constructing a board instead of the above fiber sheet, and this board is obtained by impregnating resin into reinforcing fibers. However, this plate-shaped reinforcing material is not easily conformable to a curved surface, and the construction site is limited. Therefore, in actual building reinforcement construction, it is necessary to use the above fiber sheet and the above board together or separately, resulting in an increase in the number of processes and the types of materials, and the construction becomes complicated.

[0004] In the building reinforcement method described in Patent Document 2, the following steps are required: a step of coating a curable polymer on the building surface; a step of curing the above curable polymer to form a first layer; a step of heating the open surface of the first layer; and a step of bonding a second layer containing reinforcing fibers and a thermoplastic base material on the surface of the heated first layer. In this kind of reinforcement method, it is necessary to heat the surface of the cured first layer at the construction site, so a large amount of equipment and labor are required.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Publication No. 5380551

[0008] Patent Document 2: Japanese Patent Publication No. 6043485 SUMMARY OF THE INVENTION

[0009] TECHNICAL PROBLEM TO BE SOLVED BY THE INVENTION

[0010] In Japan, due to the shortage of civil engineering workers accompanied by the decline in the birth rate and the aging of the population, and the fact that many buildings such as bridges or roads are simultaneously entering the repair period, there is a strong demand for the simplification of the construction method when using reinforcing fiber materials to reinforce buildings. Therefore, the present inventor has sought a building reinforcement material that can be constructed with fewer processes and simpler operations.

[0011] MEANS FOR SOLVING THE TECHNICAL PROBLEM

[0012] As a result, the present inventor has solved the above problems with a sheet for building reinforcement formed of a new material and having excellent properties. That is, the present invention is as follows.

[0013] (Invention 1)

[0014] A sheet for building reinforcement formed of a prepreg containing an engineering plastic and carbon fiber, the engineering plastic being formed of one or more selected from polyphenylene sulfide resin, polycarbonate, and polyether ether ketone,

[0015] The sheet for building reinforcement has at least one surface showing a water contact angle of 50 degrees or less.

[0016] (Invention 2)

[0017] The sheet for building reinforcement according to Invention 1, wherein in the adhesion test according to JSCE-E 545-2018, it shows an adhesion strength of 1.5 MPa or more and substrate failure.

[0018] (Invention 3)

[0019] The sheet for building reinforcement according to Invention 1, wherein in the tensile test according to JSCE-E 541-2013, it shows a tensile strength of 3400 MPa or more and a tensile elastic modulus of 210 GPa or more and 280 GPa or less.

[0020] (Invention 4)

[0021] The sheet for building reinforcement according to Invention 1, wherein in the joint test according to JSCE-E 542-2018, it shows a joint strength of 3400 MPa or more and test piece failure at locations other than the adhesion surface.

[0022] (Invention 5)

[0023] The sheet for building reinforcement according to Invention 1, wherein the above-mentioned engineering plastic is formed of polyphenylene sulfide resin.

[0024] (Invention 6)

[0025] The sheet for building reinforcement according to Invention 1, wherein the weight per unit area of the above-mentioned carbon fiber is 150 g / m 2 or more.

[0026] (Invention 7)

[0027] A manufacturing method, which is a manufacturing method of a sheet for building reinforcement including the following processes 1 and 2, and these processes are as follows:

[0028] · Process 1: Manufacturing a prepreg by impregnating carbon fiber with an engineering plastic formed of one or more selected from polyphenylene sulfide resin, polycarbonate, and polyether ether ketone.

[0029] · Process 2: Making at least one surface of the above-mentioned prepreg hydrophilic.

[0030] The sheet for building reinforcement has at least one surface showing a water contact angle of 50 degrees or less.

[0031] (Invention 8)

[0032] According to the manufacturing method of Invention 7, wherein the sheet for building reinforcement shows an adhesive strength of 1.5 MPa or more and substrate failure in the adhesion test according to JSCE-E 545-2018.

[0033] (Invention 9)

[0034] According to the manufacturing method of Invention 7, wherein the sheet for building reinforcement shows a tensile strength of 3400 MPa or more and a tensile elastic modulus of 210 GPa or more and 280 GPa or less in the tensile test according to JSCE-E 541-2013.

[0035] (Invention 10)

[0036] According to the manufacturing method of Invention 7, wherein the sheet for building reinforcement shows a joint strength of 3400 MPa or more and test piece failure at locations other than the bonding surface in the joint test according to JSCE-E 542-2018.

[0037] (Invention 11)

[0038] According to the manufacturing method of Invention 7, wherein the above-mentioned engineering plastic is formed of polyphenylene sulfide resin.

[0039] (Invention 12)

[0040] According to the manufacturing method of Invention 7, in Step 2, at least one surface of the above prepreg is hydrophilized by plasma treatment.

[0041] (Invention 13)

[0042] A method for strengthening a building, the method comprising the step of bonding the sheet for strengthening a building according to any one of Inventions 1 to 6 to the surface of the building.

[0043] (Invention 14)

[0044] According to the method for strengthening a building of Invention 13, wherein the sheet for strengthening a building according to any one of Inventions 1 to 6 is bonded to the surface of the building via a curable adhesive.

[0045] Advantages of the Invention

[0046] The sheet for strengthening a building of the present invention (hereinafter, also referred to as "the sheet of the present invention") has high strength and excellent adhesion to a building. In the method for strengthening a building using the sheet of the present invention (hereinafter, also referred to as "the strengthening method of the present invention"), a resin impregnation step is not required at the construction site for strengthening. Also, since the sheet of the present invention can be easily cut, the strengthening method of the present invention can be applied to various building surfaces. According to the present invention, a building can be strengthened with fewer steps and simpler operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a view schematically showing a construction example of the sheet for strengthening a building of the present invention. DETAILED DESCRIPTION

[0048] [1. Sheet for Strengthening a Building]

[0049] [Prepreg]

[0050] The sheet of the present invention is formed from a prepreg which is a prepreg containing an engineering plastic formed from one or more selected from polyphenylene sulfide resin, polycarbonate and polyether ether ketone and carbon fiber, that is, a prepreg in which an engineering plastic formed from one or more selected from polyphenylene sulfide resin, polycarbonate and polyether ether ketone is impregnated between fibers of carbon fiber aligned in a flat long strip shape. In the present invention, it is preferable to use polyphenylene sulfide resin as the above engineering plastic.

[0051] ​The sheet of the present invention has at least one surface with a water contact angle of 50 degrees or less. This indicates that at least one surface of the above prepreg has sufficient hydrophilicity. By chemically modifying or subjecting at least one surface of the above prepreg to plasma irradiation to generate hydrophilic groups such as -OH and -COOH on the same surface, the above hydrophilicity is exhibited.

[0052] Since the sheet of the present invention is mainly composed of a sheet obtained by impregnating a resin usually selected from polyphenylene sulfide resin, polycarbonate, and polyether ether ketone as an engineering plastic into carbon fiber as a reinforcing material, it has excellent mechanical strength and heat resistance. Since the sheet of the present invention contains a thermoplastic resin, it can also be constructed on curved surfaces and details in a state where the flexibility is improved by heating.

[0053] [Polyphenylene sulfide resin]

[0054] As the above polyphenylene sulfide resin, known linear polyphenylene sulfide resins can be used without limitation. "Linear polyphenylene sulfide resin" is widely known in the technical field as a representative type of polyphenylene sulfide. The above linear polyphenylene sulfide resin is a linear polymer substantially formed by p-phenylene sulfide units in which p-phenylene units and thioether bond units are alternately bonded, and as long as a substantially linear structure is adopted, a small amount of m-phenylene sulfide units can be included. The manufacturing method of linear polyphenylene sulfide resin is also widely known. Industrially, the Phillips method of carrying out condensation polymerization of p-dichlorobenzene and sodium sulfide in N-methyl-2-pyrrolidone at 200°C to 250°C and the Dow Chemical method of carrying out self-condensation polymerization of p-bromophenylmetal salt are representative.

[0055] [Polycarbonate]

[0056] As the above polycarbonate, known polycarbonates can be used without limitation. Typically, it is manufactured by the polycondensation reaction of bisphenol A and carbonyl chloride (phosgene method) or by the transesterification method of diphenyl carbonate.

[0057] [Polyether ether ketone]

[0058] The polyether ether ketone resin is a resin formed by the following repeating structure.

[0059] [Chemical formula 1]

[0060]

[0061] [Carbon fiber]

[0062] As the above carbon fiber, the carbon fiber used in fiber-reinforced plastics (FRP) can be used without limitation. As the carbon fiber that can be used, PAN-based carbon fiber and pitch-based carbon fiber are generally used.

[0063] Regarding the ratio (weight or volume) of polyphenylene sulfide resin to carbon fiber, the thickness of one prepreg sheet, etc., they are appropriately set within the range where the sheet of the present invention has all of the following tensile properties, joint properties, and adhesion properties. When the sheet of the present invention is used for reinforcing a curved surface, the sheet can be thinned or the carbon fiber content can be reduced to improve flexibility within the range where all of the above tensile properties, joint properties, and adhesion properties are achieved.

[0064] From the viewpoint of the balance of tensile properties, joint properties, adhesion properties, and flexibility, the weight per unit area of carbon fiber in the sheet of the present invention is generally 150 g / m 2 Above, preferably 150 g / m 2 Above and 400 g / m 2 Below, more preferably 150 g / m 2 Above and 300 g / m 2 Below, the carbon fiber content of the sheet of the present invention is 20% or more and 80% or less, preferably 30% or more and 70% or less, more preferably 40% or more and 60% or less.

[0065] The sheet of the present invention can contain other thermoplastic resins as resin components in addition to the above polyphenylene sulfide resin within the range that does not impair the performance. And the sheet of the present invention can contain reinforcing fibers other than carbon fiber within the range that does not impair the performance.

[0066] [Adhesion properties]

[0067] The sheet of the present invention preferably shows an adhesion strength of 1.5 MPa or more and substrate failure in the adhesion test according to JSCE-E 545-2018 (the test method for the adhesion of continuous fiber sheets to concrete specified in the standard specification for concrete formulated by the Japan Society of Civil Engineers in 2018). The sheet of the present invention having such adhesion strength can be firmly adhered to the surfaces of various outdoor buildings such as bridges, roads, and harbors, so it is suitable for repairing these outdoor buildings.

[0068] [Tensile properties]

[0069] The sheet of the present invention preferably exhibits a tensile strength of 3400 MPa or more and a tensile elastic modulus of 210 GPa or more and 280 GPa or less in a tensile test conducted in accordance with JSCE-E 541-2013 (the tensile test method for continuous fiber sheets specified in the Standard Specifications for Concrete established by the Japan Society of Civil Engineers in 2013). The sheet of the present invention having such tensile properties can maintain and improve the strength of various outdoor structures such as bridges, roads, and harbors.

[0070] [Joint Performance]

[0071] The sheet of the present invention preferably exhibits a joint strength of 3400 MPa or more and failure of the test piece at locations other than the bonding surface in a joint test conducted in accordance with JSCE-E 542-2018 (the joint test method for continuous fiber sheets specified in the Standard Specifications for Concrete established by the Japan Society of Civil Engineers in 2018). The sheet of the present invention having such joint performance can resist pressing, vibration, torsion, etc. on the surfaces of various outdoor structures such as bridges, roads, and harbors, and thus can reinforce these outdoor structures in the long term.

[0072] By specifying the above-mentioned tensile strength, tensile elastic modulus, joint strength, and adhesiveness, the sheet of the present invention is defined as a reinforcing material for structures such as bridges or roads that has tensile strength, tensile elastic modulus, joint strength, and adhesiveness in a specific balance. The reinforcing material having such a specific balance is effective in the reinforcement construction of many structures such as bridges or roads in Japan at present.

[0073] The sheet of the present invention can be, for example, a sheet that satisfies two or more of the above-mentioned adhesiveness, tensile properties, and joint performance conditions. The sheet of the present invention can be a sheet that satisfies all of the above-mentioned adhesiveness, tensile properties, and joint performance, that is, the following sheet: it exhibits an adhesive strength of 1.5 MPa or more and failure of the base material in an adhesion test conducted in accordance with JSCE-E 545-2018 (the adhesion test method between continuous fiber sheets and concrete specified in the Standard Specifications for Concrete established by the Japan Society of Civil Engineers in 2018), a tensile strength of 3400 MPa or more and a tensile elastic modulus of 210 GPa or more and 280 GPa or less in a tensile test conducted in accordance with JSCE-E 541-2013 (the tensile test method for continuous fiber sheets specified in the Standard Specifications for Concrete established by the Japan Society of Civil Engineers in 2013), and a joint strength of 3400 MPa or more and failure of the test piece at locations other than the bonding surface in a joint test conducted in accordance with JSCE-E 542-2018 (the joint test method for continuous fiber sheets specified in the Standard Specifications for Concrete established by the Japan Society of Civil Engineers in 2018).

[0074] The sheet of the present invention has excellent mechanical strength and high adhesiveness to concrete by itself. The surface of the concrete building covered with the sheet of the present invention is firmly reinforced for a long time.

[0075] [2. Manufacturing method of sheet for building reinforcement]

[0076] The manufacturing method of the sheet of the present invention includes: Step 1 of impregnating an engineering plastic formed of one or more selected from polyphenylene sulfide resin, polycarbonate, and polyether ether ketone into carbon fiber to manufacture a prepreg; and Step 2 of hydrophilizing at least one surface of the prepreg. In the manufacturing method of the sheet of the present invention, it is preferable to use polyphenylene sulfide resin as the engineering plastic.

[0077] [Step 1]

[0078] In the above Step 1, known methods and equipment that can be used in the manufacture of prepregs obtained by impregnating a thermoplastic resin into fibers can be used without limitation. In Step 1 of the present invention, either a compression molding method or a roll pressing method can also be used. For example, a laminated sheet (Semi-preg) is manufactured, and then the above semi-preg is passed between rolls and pressed to impregnate the engineering plastic into the carbon fiber. The sheet-like carbon fiber impregnated with the engineering plastic is cooled and dried, thereby obtaining a prepreg as the raw material of the sheet of the present invention. The laminated sheet is formed of carbon fiber continuously conveyed in a straightened state and a heated engineering plastic sheet material formed of one or more selected from polyphenylene sulfide resin, polycarbonate, and polyether ether ketone.

[0079] The number of carbon fiber layers and engineering plastic layers in the semi-preg is not limited. In Step 1 of the present invention, a semi-preg in which two surface layers are formed of engineering plastic layers, and a total of n layers (n is an integer of 1 or more) of carbon fiber layers and a total of (n + 1) layers of engineering plastic layers are alternately laminated is used. Usually, a semi-preg with 1 ≤ n ≤ 5 is used, and preferably a semi-preg with 1 ≤ n ≤ 3 is used.

[0080] [Step 2]

[0081] In Step 2, it is preferable to hydrophilize at least one surface of the prepreg obtained in Step 1 by plasma treatment. Regarding the plasma treatment device and the conditions of plasma treatment, as long as the water contact angle of the above one surface becomes 50 degrees or less, preferably becomes 45 degrees or less, and more preferably becomes 35 degrees or less, there is no limitation.

[0082] Regarding the above plasma treatment, typically, the prepreg obtained in Step 1 is introduced into a drum-type plasma irradiation device or a flat-plate type plasma irradiation device, and plasma is irradiated onto at least one surface of the prepreg in the above device. It is speculated that reactive groups such as hydroxyl groups (-OH) or carboxyl groups (-COOH) are generated on the above surface through these plasma treatments. Therefore, the plasma treatment in the present invention can also be positioned as a kind of hydrophilic treatment. The sheet of the present invention obtained exhibits high adhesiveness to adhesives such as concrete or epoxy-based adhesives.

[0083] The above plasma irradiation voltage using a drum-type plasma irradiation device is usually 1.0 kV or more and 4.0 kV or less, preferably 1.5 kV or more and 3.5 kV or less, and more preferably 1.5 kV or more and 3.0 kV or less. Under the condition of obtaining an equivalent plasma irradiation intensity, plasma treatment can be performed in other ways such as a flat-plate type plasma irradiation device. In addition, plasma irradiation conditions are sometimes specified by power (W).

[0084] The sheet of the present invention has at least one surface with a water contact angle of 50 degrees or less. As the plasma irradiation condition in Step 2, it is set to a condition that the water contact angle of the surface after plasma irradiation is maintained at 50 degrees or less for at least 60 days from the end of plasma irradiation. For each type of plasma irradiation device, conditions are set such that at least one surface with a water contact angle of 50 degrees or less can be formed on the sheet of the present invention.

[0085] [3. Building reinforcement method]

[0086] The reinforcement method of the present invention includes the step of bonding the sheet of the present invention to the surface of a building. An adhesive can be used in the above bonding. In the reinforcement method of the present invention, the adhesive is not limited, and any one of inorganic adhesives such as silicon-based or cement-based adhesives, curable adhesives such as epoxy-based, amine-ester-based, acrylic-based, and silicon-based adhesives, and hot-melt adhesives can also be used. Generally, curable adhesives such as epoxy-based adhesives can be used.

[0087] In the case of using the reinforcement method of the present invention, at the construction site, an adhesive is applied to the surface of the building to be reinforced, and the sheet of the present invention is closely attached to the adhesive surface. Preferably, before the above application, the above surface is appropriately cleaned and polished. Further, it is preferable to apply a primer to the surface after the cleaning and polishing to improve the adhesion between the above surface and the above adhesive. When closely attaching the sheet of the present invention, generally, the sheet of the present invention is pressed with a roller, a brush, a trowel (scraper), etc. in such a manner that no air remains between the above adhesive and the above sheet. If the reinforced surface to which the sheet of the present invention is closely attached is dried and the above adhesive is cured, the sheet of the present invention is firmly adhered to the surface of the above building, thereby reinforcing and protecting the above surface. Thus, the reinforcement method of the present invention does not include the step of impregnating a resin into reinforcing fibers at the construction site. Therefore, compared with the conventional method, the reinforcement method of the present invention has fewer steps and does not require large equipment and complicated operations at the construction site.

[0088] In actual reinforcement construction, after the sheet of the present invention is adhered to the surface of a building, in order to further improve anti-aging property, waterproof property, antifouling property and / or in order to improve display and appearance, sometimes the outermost surface is finely coated.

[0089] In Figure 1 is schematically shown the surface of a building reinforced with the sheet of the present invention. On the surface of a concrete wall (1), a primer (2), an adhesive (3) and the sheet of the present invention (4) are laminated in sequence. In Figure 1 the example shown, the surface of the sheet of the present invention (4) is coated and processed to form a coating layer (5).

[0090] In the case where the reinforcement method of the present invention is applied to a large-area construction surface, a plurality of sheets of the present invention can be prepared and the sheets of the present invention are adhered in sequence in such a manner that the ends of the sheets overlap. Further, according to the shape and surface state of the building, it is also possible to laminate a plurality of sheets of the present invention at one part. At this time, a laminated sheet prepared by previously laminating a plurality of sheets of the present invention with the above adhesive can be prepared and the laminated sheet can be adhered to the surface to be reinforced at the construction site.

[0091] Examples

[0092] [Manufacture of Sheet for Building Reinforcement]

[0093] As the polyphenylene sulfide resin, “FORTRON” manufactured by KUREHA CORPORATION was used. Carbon fiber “TORAYCA (registered trademark) T700” manufactured by TORAY INDUSTRIES, INC. was sliced to produce carbon fiber sheets. Molten polyphenylene sulfide resin was extruded onto the above carbon fiber sheets from a T-die so that the outermost layer was a polyphenylene sulfide resin layer and the total thickness of the polyphenylene sulfide resin layer was 100 μm and the total thickness of the carbon fiber layer was 100 μm, thereby producing a prepreg. The prepreg was conveyed on a conveyor belt and heated and pressed between rollers so that the polyphenylene sulfide resin layer was impregnated into the carbon fiber. As a result, a prepreg containing carbon fiber and containing 50% by volume of carbon fiber was obtained at a basis weight of 200 g / m 2 A prepreg containing carbon fiber and containing 50% by volume of carbon fiber was obtained.

[0094] One side of the prepreg was subjected to vacuum plasma treatment to obtain the sheet of the present invention. In addition, the water contact angle was measured at five randomly selected points on the surface after plasma irradiation at regular intervals immediately after plasma irradiation, and the values of the five points were averaged. As a result, the average value of the water contact angle was maintained below 40 degrees until the 60th day after plasma irradiation.

[0095] [Manufacture of comparative sheet]

[0096] The prepreg obtained by the above method was used as a comparative sheet without plasma treatment.

[0097] [Tensile test]

[0098] Regarding the test pieces (Examples 1 to 4) obtained from the sheet of the present invention, the results of the tensile test conducted in accordance with JSCE-E 541-2013 are shown in Table 1. As shown in Table 1, the sheet of the present invention has sufficient tensile properties required for building repair materials. That is, the sheet of the present invention has achieved the goals that should be achieved in the current reinforcement of bridges or roads: the tensile strength is 3400 MPa or more and the tensile elastic modulus is 210 GPa or more and 280 GPa or less in accordance with JSCE-E 541-2013. According to the results of this tensile test, it can be said that the sheet of the present invention forms a firm reinforcement surface on the building surface and can show strong resistance to building strain, vibration, and surface cracks.

[0099] [Table 1]

[0100]

[0101] [Joint test]

[0102] For the groups consisting of two test pieces obtained from the sheets of the present invention (Examples 5 to 8) and the groups consisting of two test pieces obtained from the comparative sheets (Comparative Examples 1 to 3), the results of the joint tests conducted in accordance with JSCE-E 542-2018 are shown in Table 2. As the joint strength testing machine, AG-100KNplus manufactured by SHIMADZU CORPORATION was used. A two-component mixed epoxy adhesive manufactured by ALTECO co.,ltd. was used for joint bonding.

[0103] [Table 2]

[0104]

[0105] From the results shown in Table 2, it can be seen that the sheets of the present invention have achieved the goals that should be achieved in building repair materials: the joint strength in accordance with JSCE-E 542-2018 is 3400 MPa or more and the failure occurs at locations other than the bonding surface. Based on the results of such joint tests, it can be said that when the cut sheets of the present invention are joined to the surface of a building, the joined portion has no vulnerability and the entire surface of the building covered by the sheets of the present invention is firmly reinforced.

[0106] In contrast, the joined portions of the sheets of Comparative Examples 1 to 3 are fragile, presenting practical problems.

[0107] [Adhesion Test]

[0108] Precast reinforced concrete slabs based on JIS A 5371 were prepared. One surface of the concrete was ground with a #60 rotary grinding wheel. An epoxy resin "heat-resistant primer" manufactured by NIPPON STEEL Chemical&Material Co.,Ltd. was applied to the ground surface in an amount of 0.2 kg / m 2 and allowed to dry. A two-component mixed epoxy resin "F-30" manufactured by ALTECO co.,ltd. was applied to the surface of the dried primer in an amount of 0.6 kg / m 2 . The sheet of the present invention was attached to the applied surface and allowed to air-dry for 1 day, thereby fabricating reinforced concrete slabs (Examples 9 to 11). Also, a comparative sheet was attached to the applied surface, and reinforced concrete slabs (Comparative Examples 4 to 6) were fabricated in the same manner as in Examples 9 to 11. For the reinforced concrete slabs, the results of the adhesion tests conducted in accordance with JSCE-E 545-2018 are shown in Table 3. A Kenken-type adhesion testing machine LPT-1500 manufactured by OXJACK co.,ltd. was used for measuring the adhesion strength.

[0109] [Table 3]

[0110]

[0111] Based on the results shown in Table 3, it can be seen that the sheet of the present invention has achieved the goals that should be achieved in building repair materials: the adhesive strength is 1.5 MPa or more and the substrate is damaged in accordance with JSCE-E 545-2018. According to the results of this adhesion test, it can be said that the sheet of the present invention is not easily peeled off from the surface of the building after adhesion and exhibits a reinforcement effect for a long time.

[0112] In contrast, the sheets of Comparative Examples 4 to 6 have weak adhesion to the concrete slab and poor reinforcement effect.

[0113] [Weather resistance test]

[0114] Under the conditions based on JIS A 1415, the sheet of the present invention obtained by the above manufacturing method was exposed to a laboratory light source. This exposure is a simulation test of direct outdoor exposure. In this exposure, an Open Flame Carbon Arc Lamp (WS-A) was used as the light source, and the detailed conditions of Test Method WS-A were in accordance with those specified in JIS A 1415 (6.2 Table 5).

[0115] The tensile strength and tensile elastic modulus of the test pieces (Examples 12, 13, 14, 15) obtained from the sheet of the present invention after exposure were measured. The results of the tensile test conducted in accordance with JSCE-E 541-2013 are shown in Table 4. The results of Examples 1, 2, 3, and 4 are also shown in Table 4 for reference.

[0116] [Table 4]

[0117]

[0118] There was no significant difference in the measurement results of the tensile strength and tensile elastic modulus between the group consisting of Examples 12 to 15 and the group consisting of Examples 1 to 4. The sheet of the present invention has excellent weather resistance, and its strength is not easily reduced even when placed outdoors for a long time. Thus, it can be known that the outdoor building reinforced with the sheet of the present invention maintains good strength for a long time.

[0119] Industrial applicability

[0120] The sheet for building reinforcement of the present invention can improve the efficiency and labor-saving of building reinforcement construction. The sheet for building reinforcement of the present invention is expected to become a high-quality civil engineering building material. In particular, the sheet for building reinforcement of the present invention using polyphenylene sulfide as an engineering plastic is useful as a new and high-quality civil engineering building material.

[0121] Moreover, the sheet for building reinforcement of the present invention has good weather resistance. The sheet for building reinforcement of the present invention is effective for repairing outdoor buildings.

[0122] Symbol Explanation

[0123] 1 - Concrete wall (building), 2 - Primer, 3 - Adhesive, 4 - Sheet for building reinforcement of the present invention, 5 - Coating layer.

Claims

1. A sheet for building reinforcement, which is formed from a prepreg containing an engineering plastic and carbon fiber, and the engineering plastic is formed from one or more selected from polyphenylene sulfide resin, polycarbonate, and polyether ether ketone. The sheet for building reinforcement has at least one surface showing a water contact angle of 50 degrees or less.

2. The sheet for building reinforcement according to claim 1, wherein In the adhesion test according to JSCE-E 545-2018, it shows an adhesion strength of 1.5 MPa or more and substrate failure.

3. The sheet for building reinforcement according to claim 1, wherein In the tensile test according to JSCE-E 541-2013, it shows a tensile strength of 3400 MPa or more and a tensile elastic modulus of 210 GPa or more and 280 GPa or less.

4. The sheet for building reinforcement according to claim 1, wherein In the joint test according to JSCE-E 542-2018, it shows a joint strength of 3400 MPa or more and test piece failure at locations other than the bonding surface.

5. The sheet for building reinforcement according to claim 1, wherein The engineering plastic is formed from polyphenylene sulfide resin.

6. The sheet for building reinforcement according to claim 1, wherein The weight per unit area of the carbon fiber is 150 g / m 2 or more.

7. A manufacturing method, which is a manufacturing method of a sheet for building reinforcement including the following steps 1 and 2, and the steps are as follows: · Step 1: Impregnate carbon fiber with an engineering plastic formed from one or more selected from polyphenylene sulfide resin, polycarbonate, and polyether ether ketone to manufacture a prepreg; and · Step 2: Hydrophilize at least one surface of the prepreg, The sheet for building reinforcement has at least one surface showing a water contact angle of 50 degrees or less.

8. The manufacturing method according to claim 7, wherein The sheet for building reinforcement shows an adhesion strength of 1.5 MPa or more and substrate failure in the adhesion test according to JSCE-E 545-2018.

9. The manufacturing method according to claim 7, wherein The sheet for building reinforcement shows a tensile strength of 3400 MPa or more and a tensile elastic modulus of 210 GPa or more and 280 GPa or less in the tensile test according to JSCE-E 541-2013.

10. The manufacturing method according to claim 7, wherein The sheet for building reinforcement shows a joint strength of 3400 MPa or more and test piece failure at locations other than the bonding surface in the joint test according to JSCE-E 542-2018.

11. The manufacturing method according to claim 7, wherein The engineering plastic is formed from polyphenylene sulfide resin.

12. The manufacturing method according to claim 7, wherein In Step 2, at least one surface of the prepreg is hydrophilized by plasma treatment.

13. A building reinforcement method, which includes the step of bonding the sheet for building reinforcement according to any one of claims 1 to 6 to the surface of a building.

14. The building reinforcement method according to claim 13, wherein The sheet for building reinforcement according to any one of claims 1 to 6 is adhered to the surface of a building via a curable adhesive.

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