Method for repairing a structure using a hardening composition and a structure repaired thereby

Abstract

To overcome the drawback of the conventional repair methods that have limited environmental conditions.SOLUTION: A repair method has the steps of mixing (1) (meth) acrylate, (2) organic peroxide with a one hour half-life temperature of 90-185°C, and (3) curing accelerator, to obtain a curable composition, and of applying the obtained curable composition to a structure.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for repairing a structure using a curable composition. More specifically, for example, the present invention relates to a method for repairing a structure using a curable composition that is used in the field of civil engineering and construction, is used in the atmosphere outdoors or the like, has a sufficiently long curing rate at room temperature, is easy to mix and apply the adhesive manually, and the coating film surface hardens promptly after the work is completed.

Background Art

[0002] Conventionally, when repairing a structure in the field of civil engineering and construction, an epoxy-based adhesive has been used. However, the epoxy-based adhesive has drawbacks such as poor low-temperature curability and causing mutations and swelling to the human body. As a solution to these drawbacks, adhesives using acrylic resins have been developed. (Patent Documents 1 to 3)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, although conventional acrylic resins as described in Patent Documents 1 to 3 mentioned above are superior in low-temperature curability compared to epoxy resins, they have the drawback that curing becomes rapid in the temperature range above room temperature, and when performing manual mixing and coating operations, they will cure before the completion of construction. Therefore, when using such conventional acrylic resins in the atmosphere outdoors or the like, when mainly used in an environment with a low temperature, or when used in a high-temperature environment such as in summer, it is necessary to take measures such as curing the resin in a refrigerator or a temperature-controlled low-temperature room for a certain period of time in advance to lower the temperature of the resin itself and then using it immediately. As a result, the usage conditions are extremely restricted. There is a need for a new repair method that can overcome the drawbacks of such conventional repair methods using conventional acrylic resins.

Means for Solving the Problems

[0005] The present inventor has found that by using a specific organic peroxide, a curable composition can be obtained in which the curing time at room temperature is sufficiently long and even when applied in a thin film, it cures promptly without causing poor curing, and has thus completed the present invention that can solve the above-mentioned problems.

[0006] That is, in an embodiment of the present invention, the following can be provided.

[0007] [1] (1) (Meth)acrylate, (2) an organic peroxide having a 1-hour half-life temperature of 90 to 185°C, and (3) a curing accelerator are mixed to obtain a curable composition, The step of applying the obtained curable composition to a structure and a repair method including the same.

[0008] [2] The curable composition is of a two-component type, the first component contains at least (2) an organic peroxide having a 1-hour half-life temperature of 90 to 185°C, the second component contains at least (3) a curing accelerator, the curable composition cures within 6 hours after mixing the first component and the second component, and it takes 60 minutes or more after mixing the first component and the second component until the curable composition gels The repair method according to [1], characterized in that...

[0009] [3] (2) The repair method according to [1] or [2], wherein the organic peroxide having a half-life temperature of 90 to 185°C for 1 hour contains 1,1,3,3-tetramethylbutyl hydroperoxide.

[0010] [4] In the curable composition, (2) 0.1 to 10 parts by mass of an organic peroxide having a half-life temperature of 90 to 185°C for 1 hour is contained with respect to 100 parts by mass of (1) (meth)acrylate. The repair method according to any one of [1] to [3].

[0011] [5] The step of applying the obtained curable composition is performed under the atmosphere. The repair method according to any one of [1] to [4].

[0012] [6] A structure repaired by the repair method according to any one of [1] to [5]. [Effect of the Invention]

[0013] According to the embodiment of the present invention, by applying a curable composition containing a specific organic peroxide to a structure, the curing time of the curable composition at room temperature can be made sufficiently long, and even when applied in a thin film, it can be cured promptly without causing curing failure. Therefore, the repair of the structure can be performed efficiently. [Embodiments for Carrying Out the Invention]

[0014] Hereinafter, the present invention will be described in detail. The numerical ranges described in this specification include the upper and lower limit values unless otherwise specified. Also, in this specification, unless otherwise specified, the following definitions are made. (Meth)acrylate represents acrylate or methacrylate, and notations such as "(meth)acryloyloxy" and "(meth)acrylamide" have the same meaning.

[0015] In the repair method according to an embodiment of the present invention, a curable composition can be obtained by mixing three components: (1) (meth)acrylate, (2) an organic peroxide having a half-life temperature of 90 to 185°C for 1 hour, and (3) a curing accelerator.

[0016] Among (1) (meth)acrylates, it is preferable to contain one or more components selected from (1-1) di(meth)acrylate having a bisphenol skeleton, (1-2) dicyclopentenyl oxyalkylene (meth)acrylate, and (1-3) hydroxyalkyl (meth)acrylate in terms of large effect.

[0017] As the di(meth)acrylate having a bisphenol skeleton in (1-!1), the di(meth)acrylate represented by the following general formula (a) is preferable. As the dicyclopentenyl oxyalkylene (meth)acrylate in (1-2), the dicyclopentenyl oxyalkylene (meth)acrylate represented by the following general formula (i) is preferable. As the hydroxyalkyl (meth)acrylate in (1-3), the (meth)acrylate represented by the following general formula (u) is preferable.

[0018] Formula (a)

Chemical formula

[0019] Formula (i)

Chemical formula

[0020] Formula (u) CH2=CR5-O-(R6O) , , , , ,

[0019] , , , , , ,

[0020] , , , , q , , , -H (In the formula, R5 represents a hydrogen or methyl group, R6 represents an alkylene group having 1 to 12 carbon atoms, and q represents an integer in the range of 1 to 20)

[0021] In the general formula (a) of the component (1-1), from the viewpoint of storage stability, it is preferable that R2 and R2' in the general formula (a) are alkylene groups having no hydroxyl group. As the alkylene group having no hydroxyl group, an ethylene group is preferable.

[0022] Examples of the component (1-1) in which R2 and R2' are alkylene groups having no hydroxyl group include polyethylene glycol-modified bisphenol A di(meth)acrylate, polypropylene glycol-modified bisphenol A di(meth)acrylate, 2,2-bis(4-(meth)acryloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloxypropoxyphenyl)propane, 2,2-bis(4-(meth)acryloxytetraethoxyphenyl)propane, and the like. One or more of these can be used. Further, among these, it is preferable that R1 and R1' are protons (hydrogen atoms) in terms of high resin strength. The sum of m + n is preferably 1 or more, more preferably 2 or more, and most preferably 3 or more from the viewpoints of the resin properties and flame resistance of the cured product. The sum of m + n is preferably 30 or less, more preferably 20 or less, and most preferably 6 or less from the viewpoints of the resin properties and flame resistance of the cured product. m and n are preferably 1 or more, more preferably 2 or more from the viewpoints of the resin properties and flame resistance of the cured product. Also, since the physical properties of the desired cured product are stably exhibited, it is preferable that m = n.

[0023] The amount of the component (1-1) used is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, per 100 parts by mass in total of the (meth)acrylate. When the amount of the component (1-1) used is 80 parts by mass or less, the surface curability can be enhanced. When the amount of the component (1-1) used is 20 parts by mass or more, the resin strength of the cured product can be improved.

[0024] Component (1-2) Dicyclopentenyl oxyalkylene (meth)acrylate refers to those represented by the general formula (a). Component (1-2) has low odor and has the effect of improving surface curability.

[0025] In the general formula (a) of component (1-2), from the viewpoint of storage stability, R4 in the general formula (a) is preferably an alkylene group having no hydroxyl group. As the alkylene group having no hydroxyl group, an ethylene group is preferable.

[0026] Examples of component (1-2) include dicyclopentenyl oxyethyl (meth)acrylate, dicyclopentenyl oxyethylene glycol (meth)acrylate, dicyclopentenyl oxytriethylene glycol (meth)acrylate, and dicyclopentenyl oxypropylene glycol (meth)acrylate. Among these, dicyclopentenyl oxyethyl (meth)acrylate is preferable in terms of good surface curability and easy availability. R3 in the general formula (a) is preferably a methyl group from the viewpoint of safety to the human body. p is preferably 1 to 3, more preferably 1, in terms of high resin strength.

[0027] The amount of component (1-2) used is preferably 10 to 50 parts by mass, more preferably 20 to 45 parts by mass, per 100 parts by mass of the total (meth)acrylate. When the amount of component (1-2) used is 10 parts by mass or more, the surface curability and water resistance at high temperature can be improved. When the amount of component (1-2) used is 50 parts by mass or less, the resin strength of the cured product can be increased.

[0028] Examples of (1-3) hydroxyalkyl (meth)acrylate include 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and glycerol mono (meth)acrylate. Since component (1-3) has a hydroxyl group, it exhibits the effect of being less susceptible to adhesion to a wet surface and curing inhibition by an alkaline compound such as calcium hydroxide.

[0029] In the general formula (c) of component (1-3), from the viewpoint of storage stability, R6 in the general formula (a) is preferably an alkylene group having no hydroxyl group. As the alkylene group having no hydroxyl group, an ethylene group is preferable. R5 in the general formula (c) is preferably a methyl group from the viewpoint of safety to the human body. q is preferably 1 to 3, more preferably 1, from the viewpoint of high resin strength.

[0030] Among components (1-3), 2-hydroxyethyl (meth) acrylate is preferable because of its low odor, and 2-hydroxyethyl methacrylate is particularly preferable from the viewpoint of safety.

[0031] The amount of component (1-3) used is preferably 5 to 40 parts by mass, more preferably 10 to 35 parts by mass, per 100 parts by mass of the total of (1) (meth) acrylates. When the amount of component (1-3) used is 5 parts by mass or more, satisfactory adhesion to the wet surface can be obtained. When the amount of component (1-3) used is 40 parts by mass or less, the water resistance can be improved.

[0032] As the organic peroxide which is component (2) contained in the curable composition according to the embodiment of the present invention, those having a half-life temperature of 90 to 185°C for 1 hour are preferably used. When the half-life temperature of the organic peroxide for 1 hour is 90°C or higher, the activity does not become too high, and the effect of appropriately ensuring the handling time can be obtained. When the half-life temperature of the organic peroxide for 1 hour is 185°C or lower, the surface curability when the curable composition is applied to the object to be repaired is enhanced.

[0033] As component (2), 1,1,3,3 - tetramethylbutyl hydroperoxide (1 - hour half - life temperature 182.4 °C), 1,1 - bis(tert - butylperoxy)cyclohexane (1 - hour half - life temperature 116 °C), normal butyl - 4,4 - bis(tert - butylperoxy)valerate (1 - hour half - life temperature 129 °C), 2,2 - bis(tert - butylperoxy)butane (1 - hour half - life temperature 127 °C), diisopropylbenzene hydroperoxide (1 - hour half - life temperature 172.8 °C), paramethane hydroperoxide (1 - hour half - life temperature 151.1 °C), di - tert - butyl peroxide (1 - hour half - life temperature 149 °C), tert - butyl cumyl peroxide (1 - hour half - life temperature 137.3 °C), dicumyl peroxide (1 - hour half - life temperature 135.7 °C), 2,5 - dimethyl - 2,5 - di(tert - butylperoxy)hexane (1 - hour half - life temperature 140 °C), 2,5 - dimethyl - 2,5 - di(tert - butylperoxy)hex - 3 - yne (1 - hour half - life temperature 152 °C), dibenzoyl peroxide (1 - hour half - life temperature 92 °C), tert - butyl peroxyacetate (1 - hour half - life temperature 123 °C), tert - butyl peroxyisobutyrate (1 - hour half - life temperature 93 °C), tert - butyl peroxy - 2 - ethylhexanoate (1 - hour half - life temperature 95 °C), tert - butyl peroxylaurate (1 - hour half - life temperature 118.2 °C), tert - butyl peroxybenzoate (1 - hour half - life temperature 124.7 °C), 2,5 - dimethyl - 2,5 - di(benzoylperoxy)hexane (1 - hour half - life temperature 118.8 °C), tert - butyl peroxymaleic acid (1 - hour half - life temperature 119.0 °C), tert - butyl peroxyisopropyl monocarbonate (1 - hour half - life temperature 118.4 °C), etc. can be mentioned. These other organic peroxides can be used singly or in combination of two or more kinds.

[0034] Particularly, as component (2), it is preferable to contain 1,1,3,3-tetramethylbutyl hydroperoxide from the viewpoint of easily controlling the curing time at normal temperature and having good surface curability. 1,1,3,3-tetramethylbutyl hydroperoxide can be used alone or in combination with other organic peroxides.

[0035] The usage amount of component (2) is preferably 0.1 to 10 parts by mass, more preferably 1.0 to 5.0 parts by mass, based on 100 parts by mass in total of component (1). When the usage amount of component (2) is 0.1 part by mass or more, it is difficult to cause curing defects. Also, when the usage amount of component (2) is 10 parts by mass or less, the storage stability can be improved.

[0036] Component (3) the curing accelerator reacts with (2) the organic peroxide to generate radicals and promote the polymerization of the monomer. Examples include diethylthiourea, dibutylthiourea, ethylenethiourea, tetramethylthiourea, acetylthiourea, mercaptobenzimidazole, benzoylthiourea, N,N-diethyl-p-toluidine, N,N-dimethyl-p-toluidine, N,N-diisopropanol-p-toluidine, triethylamine, tripropylamine, ethyldiethanolamine, N,N-dimethylaniline, ethylenediamine and triethanolamine, cobalt naphthenate, copper naphthenate, zinc naphthenate, cobalt octylate, iron octylate, copper neodecanoate, copper acetylacetonate, titanium acetylacetonate, manganese acetylacetonate, chromium acetylacetonate, iron acetylacetonate, vanadyl acetylacetonate, cobalt acetylacetonate, etc. Among these, metal soaps are preferable from the viewpoint of good surface curability. As the metal soap, organic cobalt soap is preferable. As the organic cobalt soap, cobalt octylate is preferable.

[0037] The amount of component (3) used is preferably 0.1 to 10 parts by mass, more preferably 1.0 to 5.0 parts by mass, based on 100 parts by mass in total of component (1). When the amount of component (3) used is 0.1 part by mass or more, it is difficult to cause poor curing. Also, when the amount of component (3) used is 10 parts by mass or less, sufficient resin strength can be obtained.

[0038] For the curable composition according to an embodiment of the present invention, a polymerization inhibitor may be added for the purpose of improving long-term storage stability. Examples of the polymerization inhibitor include methylhydroquinone, hydroquinone, methoquinone, 2,2 - methylenebis(6 - tertiarybutyl - p - cresol), catechol, hydroquinone monomethyl ether, monoteritiarybutylhydroquinone, 2,5 - ditertiarybutylhydroquinone, p - benzoquinone, 2,5 - diphenyl - p - benzoquinone, 2,5 - ditertiarybutylcatechol, picric acid, citric acid, phenothiazine, tertiarybutylcatechol, 2 - butyl - 4 - hydroxyanisole, and 2,6 - ditertiarybutyl - p - cresol.

[0039] The amount of the polymerization inhibitor used is preferably 0.001 to 3 parts by mass, more preferably 0.01 to 2 parts by mass, based on 100 parts by mass in total of component (1).

[0040] For the curable composition according to an embodiment of the present invention, fillers such as fine powder silica, fine powder calcium carbonate, etc., which do not inhibit storage stability, may be added as needed for the purpose of improving fluidity, workability, etc. Further, a silane coupling agent or the like can be blended for improving adhesion.

[0041] The curable composition according to an embodiment of the present invention can further improve surface curability by blending paraffin. Paraffin wax is preferred as the paraffin. This effect is considered to be due to the action of alleviating the polymerization inhibition by oxygen during the radical polymerization curing of (meth)acrylate, so-called anaerobicity.

[0042] The amount of paraffin used is preferably 0.1 to 5 parts by mass, more preferably 0.3 to 2.5 parts by mass, based on 100 parts by mass in total of component (1).

[0043] Further, a colorant such as a pigment or a dye may be added as necessary, or a fragrance or the like may be used. Furthermore, the filler may be used alone, the amount may be changed, or a plurality of fillers may be used in combination, depending on the purpose.

[0044] In the repair method according to the embodiment of the present invention, the curable composition can usually be prepared by stirring and mixing components (1) to (3). Also, when using components that are solid at room temperature, such as paraffin wax, it is possible to heat and dissolve these liquids to a predetermined temperature. When the curable composition is of a two-component type, component (1) is divided into two and added to the first component and the second component, component (2) is added to the first component, and component (3) is added to the second component. For example, when used as a cement concrete repair agent, the two components may be mixed. The curable composition prepared in this way can preferably be applied, for example, by coating, spraying, or spraying on the surface of the structure under the atmosphere, and can repair defects such as cracks and fissures existing on the surface of the structure. The amount of the curable composition to be applied, sprayed, or sprayed is preferably 0.01 to 5 kg / m 2 is preferable, and 0.05 to 0.5 kg / m 2 is more preferable. Note that cement concrete is a concept including cement paste, mortar, and concrete.

Examples

[0045] Based on the following Examples 1 to 5 and Comparative Examples 1 to 2, the embodiments of the present invention will be described in detail. The unit of the amount of each substance is shown in parts by mass unless otherwise specified.

[0046] (Production of curable composition) Raw materials of the types shown in Table 1 were stirred and mixed in the composition shown in Table 1 to prepare a curable composition. For the obtained curable composition, the gelation time and the surface curing time were measured. These results are described in Table 1. As the component (1-1), bisphenol A type ethylene oxide modified dimethacrylate (in the general formula (a), R1 and R1' are methyl groups, R2 and R2' are ethylene groups, and m + n = 4), as the component (1-2), dicyclopentenyl oxyethyl methacrylate, as the component (1-3), 2-hydroxyethyl methacrylate, as the component (2), 1,1,3,3-tetramethylbutyl hydroperoxide, and as the component (3), cobalt octylate were used. Also, as the paraffin, paraffin wax (melting point 46 °C) and paraffin wax (melting point 57 °C) were used, as the polymerization inhibitor, hydroquinone, and as the other reference organic peroxide, cumene hydroperoxide was used.

[0047] (Measurement method of gelation time) The time until the curable composition gelled was measured. 50 g of a two-component curable resin composition cured for 24 hours or more in a 23 °C environment was placed in a 100 ml disposable cup and mixed well. Immediately, a K-type thermocouple (0.3×1P K-S, manufactured by Ninomiya Electric Wire Industry Co., Ltd.) was inserted, and the temperature change was measured at 1-minute intervals. The time from mixing the curable composition until it showed an exothermic peak was defined as the gelation time and described in Table 1 in minutes.

[0048] (Measurement method of surface curing time) The time until the coating film surface hardened when the curable composition was applied in a thin film was measured. In a 23 °C environment, the curable composition was applied with a brush while weighing so that the coating amount was 0.2 kg / m 2 onto a mortar test plate (dimensions: 10 mm × 70 mm × 150 mm) prepared by the method specified in JIS R 5201:2015 to obtain a test piece. The test piece was left standing in a 23 °C environment as it was, and after a certain time described later, the coating film surface was touched with a fingertip, and the time until there was no stickiness was defined as the surface curing time and described in Table 1 in time units.

[0049]

Table 1

[0050] Generally, the rate of the polymerization reaction depends on the type and amount of the initiator. The lower the activity of the initiator or the smaller the amount of the initiator, the slower the polymerization reaction. In the prior art, for the purpose of slowing down the polymerization reaction assuming use in a high-temperature environment, the type of organic peroxide has been changed to reduce the activity, or the amount of organic peroxide has been reduced to adjust the polymerization reaction of (meth)acrylate. However, for the reaction in which the polymerization is inhibited by oxygen in the air and dissolved oxygen, as the activity of the organic peroxide decreases or the amount of the organic peroxide decreases and the radical concentration decreases, the influence of the polymerization inhibition by oxygen becomes greater, and there has been a problem that the curability of the overhang portion, the coating film surface, etc. decreases. As a result of intensive studies, the present inventor has found a curable composition having good surface curability by reducing the influence of polymerization inhibition by oxygen while adjusting the polymerization reaction of (meth)acrylate by using an organic peroxide having a half-life temperature of 90 to 185°C for 1 hour.

[0051] Furthermore, among organic peroxides having a half-life temperature of 90 to 185°C for 1 hour, if they have high symmetry, the generated radicals efficiently react with the dissolved oxygen in the (meth)acrylate solution in parallel with the polymerization reaction with (meth)acrylate, so that the dissolved oxygen concentration in the system decreases, and it is presumed that the polymerization rapidly proceeds to the vicinity of the surface in the coating film. Therefore, it is considered that the surface curability becomes better. Examples of such organic peroxides include 1,1,3,3-tetramethylbutyl hydroperoxide having high symmetry in the 1,1,3,3-tetramethylbutyl structure.

Industrial Applicability

[0052] By using a curable composition having a long gelation time, excellent handleability, and good surface curability, there are the following excellent effects particularly in the repair of structures under the atmosphere. Therefore, the industrial applicability of the present invention is great. (1) Since the gelling time of the curable composition can be ensured to be 60 minutes or more, manual mixing and application operations are possible. (2) It is not necessary to use the curable composition after cooling it, and the seasons and regions where it is used are less restricted, and repair under a wide range of environmental conditions is possible. (3) Since the surface hardens within 6 hours after applying the curable composition, it leads to shortening the construction period in repair work and is efficient.

Claims

1. (1) A step of mixing a curing accelerator containing (meth)acrylate, (2) 1,1,3,3 - tetramethylbutyl hydroperoxide, and (3) metal soap to obtain a curable composition; A step of applying the obtained curable composition to a structure; comprising; (1) The (meth)acrylate contains 30 to 70 parts by mass of dimethacrylate having a bisphenol skeleton, 20 to 45 parts by mass of dicyclopentenyl oxyalkylene (meth)acrylate, and 10 to 35 parts by mass of hydroxyalkyl (meth)acrylate with respect to 100 parts by mass of the total (meth)acrylate. A repair method characterized by the above.

2. The curable composition is of a two - component type, the first component contains at least (2) 1,1,3,3 - tetramethylbutyl hydroperoxide, and the second component contains at least (3) the curing accelerator. The curable composition cures within 6 hours after mixing the first component and the second component, and it takes 60 minutes or more after mixing the first component and the second component until the curable composition gels. The repair method according to Claim 1, characterized by the above.

3. In the curable composition, 0.1 to 10 parts by mass of (2) 1,1,3,3 - tetramethylbutyl hydroperoxide is contained with respect to 100 parts by mass of (1) (meth)acrylate. The repair method according to Claim 1 or 2.

4. The step of applying the obtained curable composition is performed under the atmosphere. The repair method according to any one of Claims 1 to 3. A structure in the field of civil engineering having the curable composition applied by the repair method according to any one of Claims 1 to 4.

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