Method for preventing surface delamination of composite sheets, laminates, and structures.

Abstract

To provide a composite sheet capable of forming an anti-peeling layer with excellent strength, elongation and substrate visibility.SOLUTION: A composite sheet for preventing delamination, which is placed on the surface of a structure, includes a cured adhesive and a glass fiber sheet. The cured adhesive has a tensile modulus of 150 to 2700 MPa and the glass fiber sheet has a basis weight of 150 to 350 g / m2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a composite sheet for preventing delamination, a laminate containing the same, and a method for preventing surface delamination of a structure using the same. [Background technology]

[0002] Conventionally, various measures have been taken to prevent material spalling from structures such as tunnels and bridges. For example, Patent Document 1 describes a method for preventing concrete spalling, characterized by forming a high-strength coating on the concrete surface. Patent Document 2 describes a reinforcing coating method for strengthening the surface of a concrete structure by forming a coating layer containing a continuous glass fiber sheet. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2005-15329 [Patent Document 2] Japanese Patent Publication No. 2010-1707 [Overview of the project] [Problems that the invention aims to solve]

[0004] The spalling prevention layer formed on a structure requires sufficient strength and elongation from the standpoint of retaining spalled fragments and facilitating detection when spalling occurs.

[0005] On the other hand, the spalling prevention layer is also required to have a certain degree of transparency in order to observe deformation, cracks, etc., on the surface of the structure. However, if the amount of reinforcing fibers such as glass fibers is increased to improve strength and elasticity, the transparency of the spalling prevention layer decreases, making it difficult to see the surface of the structure beneath the spalling prevention layer.

[0006] Therefore, the present invention aims to provide a composite sheet capable of forming a peeling prevention layer with excellent strength, elongation, and substrate visibility. Furthermore, the present invention aims to provide a laminate containing the composite sheet, and a method for preventing surface peeling of a structure using the composite sheet. [Means for solving the problem]

[0007] One aspect of the present invention is a composite sheet for preventing delamination, which is placed on the surface of a structure, comprising a cured adhesive body and a glass fiber sheet, wherein the tensile modulus of the cured adhesive body is 150 to 2700 MPa, and the basis weight of the glass fiber sheet is 150 to 350 g / m². 2 This concerns composite sheets.

[0008] In one embodiment, the adhesive may be an epoxy adhesive.

[0009] A composite sheet according to one embodiment may include the glass fiber sheet and a cured body of the adhesive impregnated into the glass fiber sheet.

[0010] In one embodiment, the adhesive may be a two-component adhesive comprising a first component containing an epoxy compound and a second component containing a curing agent, and the cured body may be a cured body of a mixture of the first component and the second component.

[0011] A composite sheet according to one embodiment may have a spectral transmittance of 30% or more in the range of 380 to 780 nm.

[0012] Another aspect of the present invention relates to a laminate for preventing delamination, which is disposed on the surface of a structure, and comprises a primer layer formed by a primer and the composite sheet described above.

[0013] In one embodiment, the primer has a flexural strength of 2 N / mm² measured in accordance with the NEXCO test method for crack-impregnating materials. 2 Any primer meeting the above criteria is acceptable.

[0014] Another aspect of the present invention relates to a method for preventing surface peeling of a structure, comprising the step of arranging the composite sheet described above on the surface of the structure.

[0015] In one embodiment, the arrangement step may include a coating film forming step of forming a coating film containing the adhesive and the glass fiber sheet on the surface of the structure, and a sheet forming step of curing the coating film to form the composite sheet on the surface of the structure.

[0016] A method according to one embodiment may further include a pretreatment step of applying a primer to the surface of a structure to form an undercoat layer, in which case the arrangement step may be a step of placing the composite sheet described above on the undercoat layer.

[0017] The present invention, for example, includes the following: <1> ~ <10> Regarding. <1> A composite sheet for preventing spalling, which is placed on the surface of a structure, It includes a cured adhesive and a glass fiber sheet. The tensile modulus of the hardened material is 150 to 2700 MPa. The basis weight of the aforementioned glass fiber sheet is 150-350 g / m². 2 It is a composite sheet. <2> The adhesive is an epoxy adhesive. <1> The composite sheet described above. <3> The glass fiber sheet and the cured body of the adhesive impregnated into the glass fiber sheet are included. <1> or <2> The composite sheet described above. <4> The adhesive is a two-component adhesive comprising a first component containing an epoxy compound and a second component containing a curing agent. The cured body is a cured body of a mixture of the first agent and the second agent. <1> ~ <3> A composite sheet as described in any of the following. <5> The spectral transmittance in the 380-780 nm range is 30% or higher. <1> ~ <4> A composite sheet as described in any of the following. <6> A laminate for preventing spalling, which is placed on the surface of a structure, The undercoat layer formed by the primer, <1> ~ <5> A laminate comprising a composite sheet as described in any of the above. <7> The aforementioned primer has a flexural strength of 2 N / mm² measured in accordance with the NEXCO test method for crack-impregnating materials. 2 The above are the primers. <6> The laminate described above. <8> on the surface of the structure <1> ~ <5> A method for preventing surface peeling of a structure, comprising a placement step of arranging a composite sheet as described in any of the above. <9> The aforementioned arrangement step is A coating film forming step of forming a coating film containing the adhesive and the glass fiber sheet on the surface of the structure, A sheet forming step in which the coating film is cured to form the composite sheet on the surface of the structure, including, <8> Methods used. <10> The process further includes a pretreatment step of applying a primer to the surface of the structure to form an undercoat layer. The above placement step is performed on the undercoat layer <1> ~ <5> The process involves arranging the composite sheet described in any of the following: <8> or <9> Methods used. [Effects of the Invention]

[0018] The present invention provides a composite sheet capable of forming a delamination-preventing layer with excellent strength, elongation, and substrate visibility. The present invention also provides a laminate containing the composite sheet, and a method for preventing surface delamination of a structure using the composite sheet. [Modes for carrying out the invention]

[0019] Preferred embodiments of the present invention will be described in detail below.

[0020] (Composite sheet) The composite sheet of this embodiment is a composite sheet for preventing delamination, which is placed on the surface of a structure, and includes a cured adhesive body and a glass fiber sheet. In the composite sheet of this embodiment, the tensile modulus of the cured body is 150 to 2700 MPa, and the basis weight of the glass fiber sheet is 150 to 350 g / m². 2 That is the case.

[0021] According to the composite sheet of this embodiment, a peeling prevention layer with excellent strength, elongation, and substrate visibility can be formed.

[0022] The reasons why the composite sheet of this embodiment provides the above effects are not particularly limited, but the following reasons are possible. The composite sheet of this embodiment has a glass fiber sheet basis weight of 150 g / m². 2 Therefore, it has excellent strength. Furthermore, in this embodiment, by deliberately using an adhesive with a low tensile modulus of elasticity in the cured form, the composite sheet reduces stress propagation and can bear the load over a wide area (i.e., the load per unit circumference can be kept low), so the basis weight of the glass fiber sheet is 350 g / m². 2 Even when kept below this level, excellent elongation is ensured. Furthermore, the composite sheet of this embodiment has a glass fiber sheet basis weight of 350 g / m². 2 Therefore, sufficient visibility of the underlying surface is ensured.

[0023] In the composite sheet of this embodiment, examples of adhesives include epoxy adhesives, urethane adhesives, silicone adhesives, and acrylic adhesives. Of these, epoxy adhesives are preferred from the viewpoint of superior adhesion to concrete surfaces, primer layers, glass fiber sheets, etc.

[0024] The form of the adhesive is not particularly limited, but for example, it may be a two-component adhesive. A preferred embodiment of a two-component adhesive will be described below.

[0025] <Two-part adhesive> A two-component adhesive according to one preferred embodiment comprises a first component containing an epoxy compound and a second component containing a curing agent.

[0026] Two-component adhesives can form a cured body by mixing a first component and a second component. That is, when using a two-component adhesive, the cured body of the adhesive can be said to be a cured body of a mixture of the first component and the second component. Two-component adhesives may be provided as a two-component adhesive kit comprising, for example, a first component, a first container containing the first component, a second component, and a second container containing the second component, or as a two-component adhesive kit comprising a first component, a second component, and containers in which the first and second components are individually contained.

[0027] Two-part adhesives may be room-temperature curing type.

[0028] When using a two-component adhesive, it is preferable to mix the first and second components so that the ratio of the epoxy equivalent of the epoxy compound to the active hydrogen equivalent of the curing agent is 1:1, but the mixing ratio is not limited to this. For example, the first and second components may be mixed so that the ratio of the active hydrogen equivalent of the curing agent to the epoxy equivalent of the epoxy compound is 0.5 to 1.5 (preferably 0.8 to 1.2). That is, the ratio of the active hydrogen equivalent of the curing agent to the epoxy equivalent of the epoxy compound may be, for example, 0.5 to 1.5, 0.5 to 1.2, 0.8 to 1.5, or 0.8 to 1.2.

[0029] Epoxy compounds may be used individually or in combination of two or more. Examples of epoxy compounds include compounds having one epoxy group and compounds having two or more epoxy groups. Preferably, the epoxy compound contains at least one compound having two or more epoxy groups.

[0030] As for epoxy compounds, compounds having a glycidyl group as the epoxy group are preferred. That is, epoxy compounds preferably contain compounds having a glycidyl group, and preferably contain compounds having two or more glycidyl groups.

[0031] Examples of the epoxy compound include, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A bis(polypropylene glycol glycidyl ether) ether, bisphenol A bis(polyethylene glycol glycidyl ether) ether, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, biphenyl type epoxy resin, urethane-modified epoxy resin, rubber-modified epoxy resin, alkyl glycidyl ether, cresyl glycidyl ether, phenyl glycidyl ether, alkyl diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether and the like.

[0032] As a preferred example of the epoxy compound, a compound represented by the following formula (1-1) can be mentioned. [Chemical formula]

[0033] In formula (1-1), p represents an integer of 0 or more, and R 11 and R 12 each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms which may have a substituent, or a phenyl group which may have a substituent. When a plurality of R 11 exist, the plurality of R 11 may be the same as or different from each other. When a plurality of R 12 exist, the plurality of R 12 may be the same as or different from each other.

[0034] Examples of the substituent which the alkyl group having 1 to 5 carbon atoms in R 11 and R 12 may have include, for example, a fluorine atom, an alkoxy group (for example, an alkoxy group having 1 to 5 carbon atoms), etc., and a fluorine atom is preferable.

[0035] R 11 and R 12Examples of substituents that the phenyl group may have include a fluorine atom, an alkyl group (e.g., an alkyl group having 1 to 5 carbon atoms), an alkoxy group (e.g., an alkoxy group having 1 to 5 carbon atoms), and so on.

[0036] R 11 The group is preferably selected from the group consisting of a hydrogen atom, a methyl group, a phenyl group, and a trifluoromethyl group, more preferably selected from the group consisting of a hydrogen atom and a methyl group, and even more preferably a methyl group. 11 When there are multiple R 11 They may be the same or different from each other, but it is preferable that they be the same.

[0037] R 12 The group is preferably selected from the group consisting of a hydrogen atom, a methyl group, a phenyl group, and a trifluoromethyl group, more preferably selected from the group consisting of a hydrogen atom and a methyl group, and even more preferably a methyl group. 12 When there are multiple R 12 They may be the same or different from each other, but it is preferable that they be the same.

[0038] R 11 and R 12 They may be the same or different from each other, but it is preferable that they be the same.

[0039] p is preferably 0 to 30, more preferably 0 to 20, and even more preferably 0 to 2.

[0040] Another suitable example of an epoxy compound is the compound represented by the following formula (2-1). [ka]

[0041] In equation (2-1), n ​​and m each independently represent an integer greater than or equal to 0 (preferably an integer greater than or equal to 1), and R 1 and R 2 Each of these independently represents a hydrogen atom or a methyl group, and R3 and R 4 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms which may have substituents, or an optionally substituted phenyl group which may have substituents.

[0042] R 1 R is preferably a methyl group. 1 When there are multiple R 1 They may be the same or different from each other, but it is preferable that they be the same.

[0043] R 2 R is preferably a methyl group. 2 When there are multiple R 2 They may be the same or different from each other, but it is preferable that they be the same.

[0044] R 3 and R 4 Examples of substituents that the C1-C5 alkyl group may have include a fluorine atom and an alkoxy group (e.g., an alkoxy group having C1-C5), with a fluorine atom being preferred.

[0045] R 3 and R 4 Examples of substituents that the phenyl group may have include a fluorine atom, an alkyl group (e.g., an alkyl group having 1 to 5 carbon atoms), an alkoxy group (e.g., an alkoxy group having 1 to 5 carbon atoms), and so on.

[0046] R 3 Preferably, the group is selected from the group consisting of a hydrogen atom, a methyl group, a phenyl group, and a trifluoromethyl group, more preferably a group selected from the group consisting of a hydrogen atom and a methyl group, and even more preferably a methyl group.

[0047] R 4 Preferably, the group is selected from the group consisting of a hydrogen atom, a methyl group, a phenyl group, and a trifluoromethyl group, more preferably a group selected from the group consisting of a hydrogen atom and a methyl group, and even more preferably a methyl group.

[0048] R 3 and R 4 They may be the same or different from each other, but it is preferable that they be the same.

[0049] n and m are preferably n+m = 2 to 20, and more preferably n+m = 2 to 11.

[0050] The curing agent may be any component that reacts with the epoxy compound and can cure the mixture of the first and second components. For example, the curing agent may be a compound having two or more reaction sites that can react with the epoxy groups in the epoxy compound. One type of curing agent may be used alone, or two or more types may be used in combination.

[0051] As a curing agent, an amine-based curing agent is preferred.

[0052] As an amine-based curing agent, an amine compound having a group selected from the group consisting of a primary amino group and a secondary amino group is preferred. The primary amino group of the amine compound is a group represented by -NH2. The secondary amino group of the amine compound is a group represented by -NH-. The amine-based curing agent may be, for example, a compound having one or more primary amino groups, or a compound having two or more secondary amino groups, etc.

[0053] The amine-based curing agent may be at least one selected from the group consisting of, for example, aliphatic amines, alicyclic amines, modified aliphatic polyamines, modified alicyclic amines, and polyamidoamines, and is preferably at least one selected from the group consisting of modified aliphatic polyamines, modified alicyclic amines, and polyamidoamines.

[0054] The active hydrogen equivalent of the amine-based curing agent may be, for example, 20 or more, preferably 50 or more, and more preferably 70 or more. This makes it easier to reduce the amount of nitrogen element in the adhesive, and makes it easier to obtain a cured product with a low nitrogen element content. Alternatively, the active hydrogen equivalent of the amine-based curing agent may be, for example, 200 or less, preferably 150 or less, more preferably 120 or less, and may even be 100 or less. This tends to form a denser crosslinked structure, further improving the heat resistance and durability of the cured product. In other words, the active hydrogen equivalent of the amine-based curing agent may be, for example, 20-200, 20-150, 20-120, 20-100, 50-200, 50-150, 50-120, 50-100, 70-200, 70-150, 70-120, or 70-100.

[0055] The active hydrogen equivalent of an amine-based curing agent is expressed as the mass (g) of the amine-based curing agent per mole of active hydrogen. When two or more amine-based curing agents are used in combination, the amine equivalent of the amine-based curing agents is calculated from the total amount of amine-based curing agents and the total number of active hydrogen atoms.

[0056] Two-part adhesives may contain a filler in at least one of the first and second components. The inclusion of a filler improves the viscosity of the mixture of the first and second components, thereby suppressing dripping during film formation.

[0057] Any known filler used in two-component adhesives can be used as the filler without any particular limitations. Examples of fillers include organic fillers and inorganic fillers. Furthermore, the filler may be one of these fillers that has been subjected to surface treatment such as hydrophobic treatment.

[0058] The shape of the filler is not particularly limited and may be, for example, granular, flake-like, fibrous, or emulsion-like.

[0059] Examples of organic fillers include resin particles. Resin particles may be solid, porous, or hollow. Examples of resin particles include (meth)acrylic acid ester particles and polystyrene particles.

[0060] Examples of inorganic fillers include fumed silica, calcium carbonate, talc, clay, metal oxides, metal hydroxides, and silica. The inorganic fillers may be hollow particles, fibrous particles, solid particles, or porous particles.

[0061] Inorganic fillers are preferred as fillers. Examples of inorganic fillers include fumed silica. Fumed silica has a specific surface area of ​​70 g / m². 2 (preferably 80-400 g / m²) 2 Fumed silica of the following type is preferred. Note that the specific surface area refers to the BET specific surface area. The BET specific surface area is a value measured by the gas phase adsorption method, in which gas molecules (nitrogen molecules) with a known occupied area are adsorbed onto the surface of the inorganic filler, and the specific surface area is determined from the amount of adsorbed gas molecules.

[0062] Furthermore, hydrophilic silica can be suitably used as the inorganic filler. Hydrophilic fumed silica is preferred as the hydrophilic silica.

[0063] The average particle size of the hydrophilic silica may be, for example, 1 nm or more, preferably 5 nm or more, more preferably 7 nm or more, and may also be 9 nm or more or 10 nm or more. Alternatively, the average particle size of the hydrophilic silica may be, for example, 15 nm or less, and may also be 14 nm or less. By using such hydrophilic silica, it is possible to improve the viscosity of the mixture of the first and second agents while maintaining the high transparency of the cured product, and to efficiently suppress dripping during coating film formation. That is, the average particle size of the hydrophilic silica may be, for example, 1 to 15 nm, 1 to 14 nm, 5 to 15 nm, 5 to 14 nm, 7 to 15 nm, 7 to 14 nm, 9 to 15 nm, 9 to 14 nm, 10 to 15 nm, or 10 to 14 nm.

[0064] Hydrophilic silica preferably has a degree of hydrophobicity of 30 or less, more preferably 20 or less, and even more preferably 10 or less, based on methanol wettability. Here, the degree of hydrophobicity refers to the volume fraction of methanol in the methanol-water mixture when silica is dispersed in water and methanol is added dropwise, at which point all of the suspended silica settles. The measurement can be performed, for example, by adding 0.2 g of silica to 50 ml of deionized water and adding methanol dropwise from a burette while stirring with a magnetic stirrer. The volume fraction of methanol in the methanol-water mixture at the point where all of the suspended silica has settled is the degree of hydrophobicity.

[0065] Commercially available hydrophilic silica can be used. Examples of commercially available hydrophilic silica include AEROSIL 150, 200, 300, 380 (manufactured by Evonik), RHEOROSIL QS-10, QS-102, CP-102, QS-20, QS-20L, QS-30, QS-40 (manufactured by Tokuyama Corporation), and WACKER HDK V15, N20, N20P, T30, T40 (manufactured by Asahi Kasei Wacker Silicone Co., Ltd.).

[0066] The filler content in the two-part adhesive may be, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and even more preferably 1.5% by mass or more, when the total amount of solids in the first and second components is taken as 100% by mass. This results in a more pronounced thickening effect that suppresses dripping. Alternatively, the filler content in the two-part adhesive may be, for example, 5.5% by mass or less, preferably 5.0% by mass or less, and more preferably 4.0% by mass or less, when the total amount of solids in the first and second components is taken as 100% by mass. This tends to further improve the transparency of the cured product. In other words, the filler content in a two-component adhesive may be, for example, 0.1 to 5.5% by mass, 0.1 to 5.0% by mass, 0.1 to 4.0% by mass, 0.5 to 5.5% by mass, 0.5 to 5.0% by mass, 0.5 to 4.0% by mass, 1.0 to 5.5% by mass, 1.0 to 5.0% by mass, 1.0 to 4.0% by mass, 1.5 to 5.5% by mass, 1.5 to 5.0% by mass, or 1.5 to 4.0% by mass, when the total amount of solids in the first and second components is taken as 100% by mass.

[0067] In two-part adhesives, it is preferable that at least a portion of the first and second components contains a curing accelerator. The inclusion of a curing accelerator may further improve the curability of the mixture of the first and second components.

[0068] The curing accelerator can be any agent capable of promoting the reaction between the epoxy compound and the curing agent, and any known curing accelerator can be used without particular limitation. For example, monophenol compounds are preferably used as curing accelerators. Among monophenol compounds, 4-tert-butylphenol is preferred.

[0069] The content of the curing accelerator in the two-part adhesive may be, for example, 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 1.0% by mass or more, when the total amount of solids in the first and second components is taken as 100% by mass. This tends to further improve the curability of the mixture of the first and second components. Alternatively, the content of the curing accelerator in the two-part adhesive may be, for example, 5.5% by mass or less, preferably 5.0% by mass or less, and more preferably 4.5% by mass or less, when the total amount of solids in the first and second components is taken as 100% by mass. This tends to suppress the residue of unreacted substances and improve durability. In other words, the content of the curing accelerator in the two-component adhesive may be, for example, 0.1 to 5.5% by mass, 0.1 to 5.0% by mass, 0.1 to 4.5% by mass, 0.5 to 5.5% by mass, 0.5 to 5.0% by mass, 0.5 to 4.5% by mass, 1.0 to 5.5% by mass, 1.0 to 5.0% by mass, or 1.0 to 4.5% by mass, when the total amount of solids in the first and second components is taken as 100% by mass.

[0070] The two-part adhesive may further contain other components besides those mentioned above. Examples of other components include curing retarders, light stabilizers, light absorbers, antioxidants, degradation inhibitors, pigments, dyes, silane coupling agents, defoamers, leveling agents, dispersants, rheology control agents, waxes, solvents, and water. Among these, rheology control agents are preferred.

[0071] Rheology control agents suppress dripping and improve the workability of two-part adhesives. A rheology control agent is preferably an amide. Examples of amides include higher fatty acid amides, polyamides, and amide oligomers. Polyaminoamides are preferred as the amide.

[0072] The content of the rheology control agent in the two-part adhesive may be, for example, 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, and even more preferably 1.0% by mass or more, when the total amount of solids in the first and second components is taken as 100% by mass. This results in a more pronounced thickening effect that suppresses dripping. The content of the rheology control agent may be, for example, 7.0% by mass or less, preferably 5.0% by mass or less, and more preferably 3.0% by mass or less, when the total amount of solids in the first and second components is taken as 100% by mass. This tends to further improve the tensile properties. In other words, the content of the rheology control agent in the two-component adhesive may be, for example, 0.01 to 7.0% by mass, 0.01 to 5.0% by mass, 0.01 to 3.0% by mass, 0.05 to 7.0% by mass, 0.05 to 5.0% by mass, 0.05 to 3.0% by mass, 0.1 to 7.0% by mass, 0.1 to 5.0% by mass, 0.1 to 3.0% by mass, 0.5 to 7.0% by mass, 0.5 to 5.0% by mass, 0.5 to 3.0% by mass, 1.0 to 7.0% by mass, 1.0 to 5.0% by mass, or 1.0 to 3.0% by mass, when the total amount of solids in the first and second components is taken as 100% by mass.

[0073] The first agent comprises an epoxy compound, may optionally contain a filler, and may further contain other components as needed.

[0074] The epoxy compound content in the first component may be, for example, 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, and may also be 100% by mass, based on the total amount of solids in the first component.

[0075] The second agent contains an amine-based curing agent, may optionally contain a filler, and may further contain other components as needed.

[0076] The content of the amine-based curing agent in the second component may be, for example, 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and may also be 100% by mass, based on the total amount of solids in the second component.

[0077] In a two-component adhesive, it is preferable that the mixture of the first and second components exhibits a viscosity of 2,000 mPa·s to 100,000 mPa·s (more preferably 4,000 mPa·s to 50,000 mPa·s, i.e., for example, 2,000 to 100,000 mPa·s, 2,000 to 50,000 mPa·s, 4,000 to 100,000 mPa·s, or 4,000 to 50,000 mPa·s) and a thixotropic index of 2.0 or higher (more preferably 3.0 to 8.0, i.e., for example, 2.0 or higher, 2.0 to 8.0, or 3.0 to 8.0). Note that the viscosity and thixotropic index of the mixture of the first and second components change over time due to the reaction between the epoxy compound and the curing agent. That is, the above specification means that the mixture of the first and second components exhibits the above viscosity and thixotropic index for a certain period after mixing.

[0078] In this specification, the viscosity of the mixture of the first and second components is expressed as the viscosity at 23°C and 20 rpm, as measured by a cone-plate rotary viscometer. The thixotropic index is expressed as the ratio (V2 / V1) of the viscosity V2 at 23°C and 20 rpm to the viscosity V1 at 23°C and 20 rpm, as measured by a cone-plate rotary viscometer.

[0079] The cured adhesive preferably has a spectral transmittance of 30% or more in the visible light region (380-780 nm) per 1 mm thickness. In this specification, the spectral transmittance of the cured adhesive is measured using a Shimadzu Corporation SolidSpec-3700i UV-VIS-NIR spectrophotometer. This makes it easier to obtain a peel-resistant layer with superior substrate visibility.

[0080] The tensile modulus of the cured adhesive is 150 MPa or higher, preferably 300 MPa or higher, more preferably 500 MPa or higher, even more preferably 700 MPa or higher, and even more preferably 1000 MPa or higher. This tends to further improve the heat resistance of the cured adhesive. Alternatively, the tensile modulus of the cured adhesive is 2700 MPa or lower, preferably 2500 MPa or lower, and more preferably 2200 MPa or lower. This results in a more pronounced effect than described above, and particularly tends to improve elongation at low temperatures. In other words, the tensile modulus of the cured adhesive may be, for example, 150-2700 MPa, 150-2500 MPa, 150-2200 MPa, 300-2700 MPa, 300-2500 MPa, 300-2200 MPa, 500-2700 MPa, 500-2500 MPa, 500-2200 MPa, 700-2700 MPa, 700-2500 MPa, 700-2200 MPa, 1000-2700 MPa, 1000-2500 MPa, or 1000-2200 MPa.

[0081] The tensile strength of the cured adhesive is not particularly limited and may be, for example, 5 MPa or more, preferably 10 MPa or more, and more preferably 20 MPa or more. This tends to further improve the heat resistance of the cured adhesive. The tensile strength of the cured adhesive may also be, for example, 80 MPa or less, 60 MPa or less, or 40 MPa or less. That is, the tensile strength of the cured adhesive may be, for example, 5 to 80 MPa, 5 to 60 MPa, 5 to 40 MPa, 10 to 80 MPa, 10 to 60 MPa, 10 to 40 MPa, 20 to 80 MPa, 20 to 60 MPa, or 20 to 40 MPa.

[0082] <Glass fiber sheet> The composite sheet of this embodiment includes a glass fiber sheet.

[0083] The composition of the glass constituting the glass fiber sheet is not particularly limited and may be, for example, E glass, AR glass, S glass, C glass, D glass, ECR glass, etc.

[0084] The fineness of the glass fiber sheet may be, for example, 50 tex or more, preferably 70 tex or more, and more preferably 130 tex or more. This makes it easier for openings to form between the fibers, allowing the adhesive to penetrate more easily and improving workability during the manufacture of the composite sheet. Alternatively, the fineness of the glass fiber sheet may be, for example, 1500 tex or less, preferably 1000 tex or less, and more preferably 500 tex or less. This increases the density of the fibers and improves handling. In other words, the fineness of the glass fiber sheet may be, for example, 50-1500 tex, 50-1000 tex, 50-500 tex, 70-1500 tex, 70-1000 tex, 70-500 tex, 130-1500 tex, 130-1000 tex, or 130-500 tex.

[0085] The composite sheet of this embodiment can be manufactured, for example, by a manufacturing method comprising a coating step of applying an adhesive (for example, a mixture of a first agent and a second agent) to a glass fiber sheet to form a coating film, and a curing step of curing the coating film.

[0086] Furthermore, the composite sheet of this embodiment can also be manufactured by a manufacturing method comprising, for example, a placement step of placing a glass fiber sheet on an adhesive coating and a curing step of curing the coating.

[0087] In the coating process, some or all of the adhesive may be impregnated into the fiberglass sheet. Alternatively, the coating process may be a process of applying the adhesive to a fiberglass sheet placed on the surface of a structure.

[0088] In the coating process, the amount of adhesive applied is, for example, 200 g / m². 2 The amount may be greater than or equal to 400 g / m², preferably 400 g / m². 2 Above, a comfortable 500g / m 2 That concludes the explanation. Furthermore, the amount of adhesive to be applied should be, for example, 1500 g / m². 2 The following may be true, preferably 1000 g / m² 2 More preferably, 700g / m² 2The following applies. This makes it easier to obtain a composite sheet in which the content of the cured adhesive is within the preferred range described later. That is, the amount of adhesive applied is, for example, 200 to 1500 g / m². 2 200-1000g / m 2 200-700g / m 2 400-1500g / m 2 400-1000g / m 2 400-700g / m 2 500-1500g / m 2 500-1000g / m 2 , or 500-700g / m 2 That's fine.

[0089] In the placement process, some or all of the adhesive may be impregnated into the glass fiber sheet. Alternatively, the placement process may be a process of placing the glass fiber sheet on an adhesive coating formed on the surface of the structure.

[0090] The curing step may be, for example, a step of curing the adhesive coating by heating. The heating temperature may be set appropriately depending on the type of adhesive and curing agent, etc.

[0091] In the composite sheet of this embodiment, the basis weight of the glass fiber sheet is 150 g / m². 2 The above is preferable, preferably 170 g / m² 2 Above, 200g / m² is more comfortable. 2 That concludes the explanation. This makes it easier to obtain a peel-resistant layer with superior strength and elongation. The basis weight of the glass fiber sheet is 350 g / m². 2 The following, preferably 300 g / m² 2 More preferably, 250 g / m² 2 The following applies. This makes it easier to obtain a peel-resistant layer with superior visibility of the substrate. Specifically, the basis weight of the glass fiber sheet is, for example, 150-350 g / m². 2 150-300g / m 2 150-250g / m 2 , 170~350g / m 2 , 170~300g / m 2 , 170~250g / m2 , 200 to 350 g / m 2 , 200 to 300 g / m 2 , or 200 to 250 g / m 2 may be.

[0092] In the composite sheet of this embodiment, the content of the cured body of the adhesive is, for example, 200 g / m 2 or more, preferably 400 g / m 2 or more, more preferably 500 g / m 2 or more. Thereby, the surface smoothness of the composite sheet is further improved, and it becomes easier to obtain a peeling prevention layer with more excellent base visibility. The content of the cured body of the adhesive is, for example, 1500 g / m 2 or less, preferably 1000 g / m 2 or less, more preferably 700 g / m 2 or less. Thereby, the generation amount of harmful components during combustion of the cured body tends to be reduced. That is, the content of the cured body of the adhesive is, for example, 200 to 1500 g / m 2 , 200 to 1000 g / m 2 , 200 to 700 g / m 2 , 400 to 1500 g / m 2 , 400 to 1000 g / m 2 , 400 to 700 g / m 2 , 500 to 1500 g / m 2 , 500 to 1000 g / m 2 , or 500 to 700 g / m 2 may be.

[0093] The thickness of the composite sheet is not particularly limited, but may be, for example, 0.25 mm or more, preferably 0.4 mm or more, more preferably 0.5 mm or more. Also, the thickness of the composite sheet may be, for example, 1.6 mm or less, preferably 1.2 mm or less, more preferably 0.8 mm or less. That is, the thickness of the composite sheet may be, for example, 0.25 to 1.6 mm, 0.25 to 1.2 mm, 0.25 to 0.8 mm, 0.4 to 1.6 mm, 0.4 to 1.2 mm, 0.4 to 0.8 mm, 0.5 to 1.6 mm, 0.5 to 1.2 mm, or 0.5 to 0.8 mm.

[0094] The spectral transmittance of the composite sheet in the visible light region (380-780 nm) of this embodiment is, for example, 30% or more, preferably 40% or more, more preferably 50% or more, even more preferably 60% or more, and even more preferably 70% or more. This makes it easier to obtain a peel-resistant layer with superior visibility of the substrate. In this specification, the spectral transmittance of the composite sheet is measured using a Shimadzu Corporation SolidSpec-3700i UV-VIS-NIR spectrophotometer.

[0095] The composite sheet of this embodiment is placed on the surface of a structure to prevent concrete fragments and other materials from peeling off from the structure's surface. Further layers other than the composite sheet may be formed on the surface of the structure. That is, a laminate of the composite sheet and other layers may be formed on the surface of the structure.

[0096] Examples of laminates include those comprising a primer-formed undercoat layer and a composite sheet.

[0097] The primer has a flexural strength of 2 N / mm², measured according to the NEXCO test method for crack-impregnating materials. 2 Any primer meeting the above criteria is acceptable.

[0098] The viscosity of the primer is not particularly limited, but may be, for example, 100 mPa·s or more, preferably 200 mPa·s or more, and more preferably 400 mPa·s or more. This tends to prevent absorption into the substrate and facilitate coating film formation. Alternatively, the viscosity of the primer may be, for example, 4000 mPa·s or less, preferably 2000 mPa·s or less, and more preferably 1000 mPa·s or less. This tends to further improve impregnation into cracks on the surface of the structure. In other words, the viscosity of the primer may be, for example, 100-4000 mPa·s, 100-2000 mPa·s, 100-1000 mPa·s, 200-4000 mPa·s, 200-2000 mPa·s, 200-1000 mPa·s, 400-4000 mPa·s, 400-2000 mPa·s, or 400-1000 mPa·s.

[0099] Examples of primers include epoxy primers, urethane primers, and acrylic primers. Of these, epoxy primers are preferred from the viewpoint of excellent adhesion to the surface of structures.

[0100] Furthermore, the surface of the structure may have layers formed from impregnation reinforcing materials, cross-sectional repair agents, unevenness leveling materials, etc. In other words, the laminate may further include layers formed from impregnation reinforcing materials, cross-sectional repair agents, unevenness leveling materials, etc.

[0101] The composite sheet of this embodiment can form a peeling prevention layer with excellent strength, elongation, and substrate visibility. The peeling prevention layer may be, for example, a layer made of the above-mentioned laminate.

[0102] (Methods to prevent surface spalling of structures) A method for preventing surface peeling of a structure may include a placement step of placing the composite sheet described above on the surface of the structure.

[0103] The arrangement step may include a coating film forming step of forming a coating film containing an adhesive and a glass fiber sheet on the surface of the structure, and a sheet forming step of curing the coating film to form a composite sheet on the surface of the structure.

[0104] The coating film formation process may be, for example, a process of placing a glass fiber sheet on the surface of a structure and applying an adhesive to the glass fiber sheet to form a coating film.

[0105] Alternatively, the coating film formation process may involve applying an adhesive to the surface of the structure, and then placing a glass fiber sheet on the applied adhesive to form a coating film.

[0106] The above method may further include a pretreatment step of applying a primer to the surface of the structure to form an undercoat layer. If a pretreatment step is included, the coating film formation step may be a step of forming a coating film on the undercoat layer.

[0107] The above method may further include a topcoat step of forming a topcoat layer on the composite sheet. Any topcoat layer used for known peeling prevention layers can be used without particular limitation as the topcoat layer. The topcoat layer may be, for example, a protective coating, a topcoat layer, etc.

[0108] The surface of the structure is not particularly limited, but a concrete surface or a mortar surface is preferred from the viewpoint of obtaining a significant effect in preventing material spalling.

[0109] Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. [Examples]

[0110] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0111] The abbreviations for each component used in the examples and comparative examples, as well as the test methods performed in the examples and comparative examples, are as follows.

[0112] <Epoxy compounds> • Adeka Resin EP-4100 (EP4100 in the table): An epoxy compound having the structure of formula (1-1) (manufactured by Adeka, epoxy equivalent 190, R 11 and R 12 (This is a methyl group) • Adeka Resin EP-4005 (EP4005 in the table): An epoxy compound having the structure of formula (2-2) (manufactured by Adeka, epoxy equivalent 510) • Adeka Resin EP-4000 (referred to as "EP4000" in the table): An epoxy compound having the structure of formula (2-2) (manufactured by Adeka, epoxy equivalent 320) • SY-OCG: Orthocresyl glycidyl ether (manufactured by Sakamoto Pharmaceutical Co., Ltd., epoxy equivalent 180) [ka] [In the formula, n and m each represent an integer greater than or equal to 1.]

[0113] <Filler> ·AEROSIL 200 (AS200 in the table): Hydrophilic fumed silica (primary particle diameter 12 nm, BET specific surface area 200 g / m 2 (Hydrophobicity 0%, manufactured by Evonik)

[0114] <Amine-based curing agent> • Tomid 235-A (235A in the table): Polyamidoamine (manufactured by T&K TOKA, active hydrogen equivalent 95) • Fujicure 8116 (8116 in the table): Modified alicyclic polyamine (manufactured by T&K TOKA, active hydrogen equivalent 72) • Tomid 245-S (245-S in the table): Polyamidoamine (manufactured by T&K TOKA, active hydrogen equivalent 80)

[0115] <Other ingredients> • BYK R607: Polyaminoamide (Rheology control agent (RC agent in the table), manufactured by BYK Chemie Co., Ltd.)

[0116] <Glass fiber sheet> ·G1 (basis weight: 200 g / m 2 , fineness: 135 tex) ·G2 (basis weight: 184 g / m 2 , fineness: 70 tex) ·G3 (basis weight: 256 g / m 2 , fineness: 135 tex) ·G4 (basis weight: 300 g / m 2 , fineness: 400 tex) ·G5 (basis weight: 400 g / m 2 , fineness: 600 tex)

[0117] <Primer> ·P1 (epoxy primer, viscosity: 676 mPa·s, flexural strength measured in accordance with the test method for cracked impregnated materials of the NEXCO test method: 2.2 N / mm 2 ) ·P2 (epoxy primer, viscosity: 700 mPa·s, flexural strength measured in accordance with the test method for cracked impregnated materials of the NEXCO test method: 3.3 N / mm 2 ) ·P3 (epoxy primer, viscosity: 275 mPa·s, flexural strength measured in accordance with the test method for cracked impregnated materials of the NEXCO test method: 3.1 N / mm 2 )

[0118] <Tensile test of cured adhesive> The first agent (in the table, (1)) and the second agent (in the table, (2)) were weighed and mixed as described in Table 1, Table 2, or Table 3. Next, the mixture was poured into a mold, cured at 23°C for 7 days, demolded, and tested using a universal testing machine manufactured by A&D Company, Ltd. in accordance with JIS K7161 (Method for determining plastic tensile properties -) at an environmental temperature of 23°C and a tensile speed of 5 mm / min.

[0119] <Transmittance of composite sheet> The first agent and the second agent were weighed and mixed as described in Table 1, Table 2, or Table 3 to obtain an adhesive composition. The first agent and the second agent were mixed so that the ratio of the epoxy equivalent weight to the active hydrogen equivalent weight was 1:1. Next, apply the specified amount (0.6 kg / m²) onto the PET sheet. 2 The adhesive composition was applied to the PET film, and immediately after application, a fiber sheet was placed on top. The adhesive composition was then impregnated into the fiber sheet using a roller. After curing at 23°C for 7 days, the PET film was peeled off to obtain a composite sheet with a thickness of 0.6 mm. The spectral transmittance of the obtained composite sheet was measured in the range of 380 to 780 nm using a Shimadzu Corporation SolidSpec-3700i UV-VIS-NIR spectrophotometer. The lowest value among the measured transmittances is listed in the table.

[0120] <Penetration test of composite sheet> A core drill was performed in the center of a U-shaped side ditch (lid) of the type specified in JIS A5372 Annex E (400 x 600 x 60 mm) (hereinafter referred to as "U-shaped lid") using a concrete core drill to create a φ100 mm core. The core drilling was performed to a depth of 55 ± 3.0 mm from the opposite side of the construction surface. Under 23°C conditions, after scraping and degreasing the application surface with a disc sander, measure the specified amounts of the first and second components of the primer, mix them, and apply the specified amount (0.15 kg / m²) using a roller. 2 The mixture was applied and left to cure for one day. After curing, measure the specified amounts of the first and second components of the adhesive, mix them, and apply the specified amount (0.60 kg / m²) using a rubber spatula. 2 The material was applied, a fiber sheet was immediately attached, impregnated with a roller, the surface was smoothed with a rubber spatula, and then it was left to cure for 7 days. After curing, a load of 1 mm / min was applied to the center of the core in accordance with JSCE-K533. After the core fractured, a load of 5 mm / min was applied, and the maximum load and the displacement at that time were measured.

[0121] <Visibility of the base surface> A crack scale simulating a 0.5 mm wide crack was applied to a mortar (70 x 150 x 10 mm) prepared according to JIS R5201. Then, the specified amounts of the first and second components of the primer were measured, mixed, and applied using a roller to the specified application rate (0.15 kg / m²). 2 The mixture was applied and left to cure for one day. After curing, measure the specified amounts of the first and second components of the adhesive, mix them, and apply the specified amount (0.60 kg / m²) using a rubber spatula. 2 The material was applied, a fiber sheet was immediately attached, impregnated with a roller, the surface was smoothed with a rubber spatula, and then it was left to cure for 7 days. After curing, the presence or absence of cracks in the crack scale was evaluated visually. If the cracks were visible, it was classified as A; if they were not visible, it was classified as B.

[0122] (Example 1) An adhesive composition was obtained by mixing the first and second components, which have the compositions listed in Table 1. A tensile test was performed on the cured adhesive composition using the method described above. Next, a composite sheet was prepared and evaluated using the glass fiber sheet shown in Table 1, using the method described above. The results are shown in Table 1.

[0123] (Examples 2-12, Comparative Examples 1-2) Adhesive compositions were prepared in the same manner as in Example 1, except that the compositions of the first and second components were changed as shown in Tables 1, 2, or 3, and a tensile test of the cured product was performed using the method described above. Next, composite sheets were prepared and evaluated in the same manner as in Example 1, except that the glass fiber sheets and primers shown in Tables 1, 2, or 3 were used with the obtained adhesive compositions. The results are shown in Tables 1, 2, or 3.

[0124] [Table 1]

[0125] [Table 2]

[0126] [Table 3]

Claims

1. A composite sheet for preventing spalling, which is placed on the surface of a structure, It includes a cured adhesive and a glass fiber sheet. The tensile modulus of the hardened body is 150 to 2700 MPa. The basis weight of the aforementioned glass fiber sheet is 150 to 350 g / m². ２ And, The adhesive is a two-component adhesive comprising a first component containing an epoxy compound and a second component containing a curing agent. The cured body is a cured body of a mixture of the first agent and the second agent. A composite sheet wherein the epoxy compound comprises at least one selected from the group consisting of compounds represented by formula (1-1) and compounds represented by formula (2-1). 【Chemistry 1】 【Chemistry 2】 [In formula (1-1), p represents an integer of 0 or more, and R11 and R12 each independently represent a hydrogen atom, an optionally substituted C1-C5 alkyl group, or an optionally substituted phenyl group. In formula (2-1), n ​​and m each independently represent an integer of 0 or more, R1 and R2 each independently represent a hydrogen atom or a methyl group, and R3 and R4 each independently represent a hydrogen atom, an optionally substituted C1-C5 alkyl group, or an optionally substituted phenyl group.]

2. The composite sheet according to claim 1, comprising the glass fiber sheet and a cured body of the adhesive impregnated into the glass fiber sheet.

3. A laminate for preventing spalling, which is placed on the surface of a structure, A laminate comprising a primer layer formed by a primer and a composite sheet according to claim 1 or 2.

4. A method for preventing surface peeling of a structure, comprising the step of placing the composite sheet described in claim 1 or 2 on the surface of the structure.

5. The aforementioned arrangement step is A coating film forming step of forming a coating film containing the adhesive and the glass fiber sheet on the surface of the structure, A sheet forming step in which the coating film is cured to form the composite sheet on the surface of the structure, The method according to claim 4, including the method described in claim 4.

6. The process further includes a pretreatment step of applying a primer to the surface of the structure to form an undercoat layer. The method according to claim 4, wherein the arrangement step is the step of arranging the composite sheet on the undercoat layer.

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