JP2020026482A - Structure repair method using curable composition, and structure repaired therewith - Google Patents

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

  The present invention relates to a method for repairing a structure using a curable composition. More specifically, for example, in the field of civil engineering and construction, the present invention is used under the atmosphere such as outdoors, the curing speed is sufficiently long at room temperature, the mixing and application of the adhesive by hand is easy, and the work is quickly performed. The present invention relates to a method for repairing a structure using a curable composition that cures a coating film surface.

  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 a drawback that it is inferior in low-temperature curability and causes mutagenicity and rash on the human body. To solve these drawbacks, an adhesive using an acrylic resin has been developed. (Patent Documents 1 to 3)

Japanese Patent No. 3580681 Japanese Patent No. 6030400 Patent No. 5570867

  However, conventional acrylic resins as described in Patent Documents 1 to 3 described above are excellent in low-temperature curability as compared with epoxy resins, but have a disadvantage that curing is accelerated in a temperature range of room temperature or higher. If the mixing and coating operations are performed, they will be cured before the completion of the application. Therefore, when using such conventional acrylic resin in the atmosphere such as outdoors, mainly used in low temperature environment, or when used in high temperature environment such as summer, the resin was previously refrigerator or temperature controlled By curing the resin in a low-temperature room for a certain period of time, it is necessary to reduce the temperature of the resin itself and to use the resin immediately, for example, and the use conditions have been severely restricted. There is a need for a new repair method that can overcome the disadvantages of the conventional repair method using the conventional acrylic resin.

  The present inventor has found that by using a specific organic peroxide, a curable composition can be obtained which has a sufficiently long curing time at room temperature and which cures quickly without causing curing failure even when applied in a thin film form. And completed the present invention which can solve the above-mentioned problems.

  That is, the following can be provided in the embodiment of the present invention.

[1]
(1) mixing (meth) acrylate, (2) an organic peroxide having a one-hour half-life temperature of 90 to 185 ° C., and (3) a curing accelerator to obtain a curable composition;
Applying the obtained curable composition to a structure.

[2]
The curable composition is a two-part composition, wherein the first part contains at least (2) an organic peroxide having a one-hour half-life temperature of 90 to 185 ° C, and the second part contains at least (3) ) Containing a curing accelerator,
The curable composition is cured within 6 hours after mixing the first agent and the second agent, and the first agent and the second agent until the curable composition gels. The method according to [1], wherein it takes 60 minutes or more after mixing.

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

[4]
The curable composition contains (1) 100 parts by mass of (meth) acrylate and (2) 0.1 to 10 parts by mass of an organic peroxide having a one-hour half-life temperature of 90 to 185 ° C. The repair method according to any one of [1] to [3].

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

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

  According to the embodiment of the present invention, by applying a curable composition containing a specific organic peroxide to the structure, the curing time of the curable composition at room temperature is sufficiently long, and furthermore, the thin film Even if it is applied to the surface, it can be cured promptly without causing curing failure, so that the structure can be repaired efficiently.

  Hereinafter, the present invention will be described in detail. Unless otherwise specified, numerical ranges described in this specification include upper and lower limits. In this specification, the following definitions are used unless otherwise specified. (Meth) acrylate represents acrylate or methacrylate, and the notation such as "(meth) acryloyloxy" or "(meth) acrylamide" has the same meaning.

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

  (1) Among the (meth) acrylates, in terms of the large effect, (1-1) di (meth) acrylate having a bisphenol skeleton, (1-2) dicyclopentenyloxyalkylene (meth) acrylate, and (1-) 3) It preferably contains one or more components of hydroxyalkyl (meth) acrylate.

  As the (1-1) di (meth) acrylate having a bisphenol skeleton, a di (meth) acrylate represented by the following general formula (A) is preferable. As (1-2) dicyclopentenyloxyalkylene (meth) acrylate, dicyclopentenyloxyalkylene (meth) acrylate represented by the following general formula (a) is preferable. As the (1-3) hydroxyalkyl (meth) acrylate, a (meth) acrylate represented by the following general formula (C) is preferable.

（式中、Ｒ₁及びＲ₁’はそれぞれ独立に水素又はメチル基を表し、Ｒ₂及びＲ₂’はそれぞれ独立に１〜１２個の炭素原子を有するアルキレン基を表し、ｍ及びｎはそれぞれ独立に１〜２０の範囲の整数を表す）、 Expression (A)

(Wherein, R ₁ and R ₁ ′ each independently represent hydrogen or a methyl group, R ₂ and R ₂ ′ each independently represent an alkylene group having 1 to 12 carbon atoms, and m and n each represent Independently represents an integer in the range of 1 to 20),

（式中、Ｒ₃は水素又はメチル基を表し、Ｒ₄は１〜１２個の炭素原子を有するアルキレン基を表し、ｐは１〜２０の範囲の整数を表す） Expression (a)

(Wherein, R ₃ represents hydrogen or a methyl group, R ₄ represents an alkylene group having 1 to 12 carbon atoms, and p represents an integer in the range of 1 to 20)

Expression (C)
_{CH 2 = CR 5 -O- (R} 6 O) q -H
(Wherein, R ₅ represents hydrogen or a methyl group, R ₆ represents an alkylene group having 1 to 12 carbon atoms, and q represents an integer in the range of 1 to 20)

In the general formula (A) of the component (1-1), R ₂ and R ₂ ′ in the general formula (A) are preferably an alkylene group having no hydroxyl group from the viewpoint of storage stability. As the alkylene group having no hydroxyl group, an ethylene group is preferable.

Examples of the component (1-1) in which R ₂ and R ₂ ′ are an alkylene group having no hydroxyl group include polyethylene glycol-modified bisphenol A di (meth) acrylate, polypropylene glycol-modified bisphenol A di (meth) acrylate, and , 2-Bis (4- (meth) acryloxydiethoxyphenyl) propane, 2,2-bis (4- (meth) acryloxypropoxyphenyl) propane, 2,2-bis (4- (meth) acryloxytetra Ethoxyphenyl) propane and the like. One or more of these can be used. Further, among these, it is preferable that R ₁ and R ₁ ′ are protons (hydrogen atoms) from the viewpoint 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 viewpoint 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 viewpoint of the resin properties and burning resistance of the cured product. m and n are preferably 1 or more, and more preferably 2 or more, from the viewpoint of the resin properties and flame resistance of the cured product. In addition, it is preferable that m = n because the desired properties of the cured product are stably exhibited.

  The amount of the component (1-1) to be used is preferably 20 to 80 parts by mass, more preferably 30 to 70 parts by mass, based on 100 parts by mass of the total of (1) (meth) acrylate. When the amount of the component (1-1) is at most 80 parts by mass, the surface curability can be enhanced. When the amount of the component (1-1) is at least 20 parts by mass, the resin strength of the cured product can be improved.

  The component (1-2) dicyclopentenyloxyalkylene (meth) acrylate refers to one represented by the general formula (A). Component (1-2) has a low odor and has an effect of improving surface curability.

In the general formula (A) of the component (1-2), R ₄ in the general formula (A) is preferably an alkylene group having no hydroxyl group from the viewpoint of storage stability. As the alkylene group having no hydroxyl group, an ethylene group is preferable.

The component (1-2) includes dicyclopentenyloxyethyl (meth) acrylate, dicyclopentenyloxyethylene glycol (meth) acrylate, dicyclopentenyloxytriethylene glycol (meth) acrylate, and dicyclopentenyloxypropylene glycol (meth) A) acrylate and the like. Among them, dicyclopentenyloxyethyl (meth) acrylate is preferred because it has good surface curability and is easily available. R ₃ in the general formula (A) is preferably a methyl group from the viewpoint of safety for human bodies. p is preferably 1 to 3, and more preferably 1 in that the resin strength is large.

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

  (1-3) Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and glycerol mono (meth) acrylate. Can be Component (1-3) has an effect of having a hydroxyl group, and thus has an effect of being hardly hindered by adhesion to a wet surface and hardening by an alkaline compound such as calcium hydroxide.

In the general formula (C) of the component (1-3), R ₆ in the general formula (A) is preferably an alkylene group having no hydroxyl group from the viewpoint of storage stability. As the alkylene group having no hydroxyl group, an ethylene group is preferable. R ₅ in the general formula (C) is preferably a methyl group from the viewpoint of safety for human bodies. q is preferably 1 to 3, and more preferably 1 in that the resin strength is large.

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

  The amount of the component (1-3) to be used is preferably 5 to 40 parts by mass, more preferably 10 to 35 parts by mass, based on 100 parts by mass of the total of (1) (meth) acrylate. When the use amount of the component (1-3) is 5 parts by mass or more, satisfactory adhesion to a wet surface can be obtained. The water resistance in which the amount of the component (1-3) used is 40 parts by mass or less can be improved.

  As the component (2) organic peroxide contained in the curable composition according to the embodiment of the present invention, one having a one-hour half-life temperature of 90 to 185 ° C is suitably used. When the one-hour half-life temperature of the organic peroxide is 90 ° C. or higher, the effect is obtained that the activity does not become too high and the handling time can be appropriately secured. When the one-hour half-life temperature of the organic peroxide is 185 ° C. or lower, the effect of increasing the surface curability when the curable composition is applied to the repair target can be obtained.

  Component (2) includes 1,1,3,3-tetramethylbutyl hydroperoxide (1 hour half-life temperature 182.4 ° C.) and 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), paramenthane hydroperoxide (1 hour half-life temperature 151.1 ° C), ditertiary butyl peroxide (1 hour half-life temperature 149 ° C), tertiary Butylcumyl 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) hexyne-3 (1 hour half-life temperature 152 ° C), dibenzoyl peroxide (1 hour half-life temperature 92 ° C), tertiary butyl peroxyacetate (1 hour half-life temperature 123 ° C), tertiary butyl peroxyisobutyrate (1 hour) 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.), tertiary butyl peroxymaleic acid (1 hour half-life temperature 119.0 ° C.), tertiary butyl peroxyisopropyl monocarbonate (1 hour half-life temperature 118.4 ° C.) and the like. One or more of these other organic peroxides can be used.

  In particular, it is preferable to include 1,1,3,3-tetramethylbutyl hydroperoxide as the component (2) from the viewpoint that the curing time at normal temperature can be easily controlled and the surface curability is good, 1,1,3,3-tetramethylbutyl hydroperoxide may be used alone or in combination with other organic peroxides.

  The amount of the component (2) to be 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 of the total of the component (1). If the amount of the component (2) is 0.1 parts by mass or more, poor curing is unlikely to occur. When the amount of the component (2) is 10 parts by mass or less, storage stability can be improved.

  The component (3) curing accelerator reacts with (2) an organic peroxide to generate a radical and promotes polymerization of a monomer, and is composed of diethylthiourea, dibutylthiourea, ethylenethiourea, tetramethylthiourea, and 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 acetyl Setoneto, chromium acetylacetonate, iron acetylacetonate, vanadyl acetylacetonate, cobalt acetylacetonate, and the like. Of these, metal soaps are preferred from the viewpoint of good surface curability. As the metal soap, an organic cobalt soap is preferable. As the organic cobalt soap, cobalt octylate is preferable.

  The amount of the component (3) to be used is preferably 0.1 to 10 parts by mass, more preferably 1.0 to 5.0 parts by mass, per 100 parts by mass of the total of the component (1). If the amount of the component (3) is 0.1 parts by mass or more, poor curing is unlikely to occur. When the amount of the component (3) is 10 parts by mass or less, a sufficient resin strength can be obtained.

  A polymerization inhibitor may be added to the curable composition according to the embodiment of the present invention for the purpose of improving long-term storage stability. Examples of the polymerization inhibitor include methylhydroquinone, hydroquinone, methoquinone, 2,2-methylenebis (6-tert-butyl-p-cresol), catechol, hydroquinone monomethyl ether, mono-tert-butyl hydroquinone, and 2,5-di-tert-butyl hydroquinone. , P-benzoquinone, 2,5-diphenyl-p-benzoquinone, 2,5-di-tert-butylcatechol, picric acid, citric acid, phenothiazine, tert-butylcatechol, 2-butyl-4-hydroxyanisole and 2,6- Ditertiary butyl-p-cresol and the like.

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

  In the curable composition according to the embodiment of the present invention, for the purpose of improving fluidity and workability, a filler that does not impair storage stability, for example, fine powder silica, fine powder calcium carbonate, and the like, You may add as needed. Further, a silane coupling agent or the like can be blended for improving the adhesion.

  The curable composition according to the embodiment of the present invention can further improve surface curability by blending paraffin. As the paraffin, paraffin wax is preferable. This effect is considered to be caused by inhibition of polymerization by oxygen at the time of radical polymerization curing of (meth) acrylate, that is, an effect of relieving anaerobicity.

  The amount of paraffin to be 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 of the component (1) in total.

  If necessary, a coloring agent such as a pigment or a dye may be added, or a fragrance or the like may be used. Further, the filler may be used alone, may be varied in amount, or may be used in combination with a plurality of fillers, depending on the purpose.

In the repair method according to the embodiment of the present invention, the curable composition can be usually prepared by stirring and mixing components (1) to (3). When a component that is solid at room temperature, for example, paraffin wax, is used, these liquids can be heated to a predetermined temperature and dissolved. When the curable composition is of a two-part type, component (1) is divided into two parts and added to the first part and the second part. Component (2) is added to the first part and component (3) is added to the second part. ) May be added and, for example, when used as a cement concrete repair agent, two agents may be mixed. The curable composition thus prepared can be applied to the surface of the structure by applying, spraying, spraying, or the like, preferably in the atmosphere, and removes defects such as cracks and cracks present on the surface of the structure. Can be repaired. The curable composition coating, the amount of spraying or spraying is preferably ^{0.01~5kg / m 2, 0.05~0.5kg / m} 2 is more preferable. Note that cement concrete is a concept that includes cement paste, mortar, and concrete.

  Embodiments of the present invention will be described in detail based on the following Examples 1 to 5 and Comparative Examples 1 and 2. The unit of the amount of each substance used is shown in parts by mass unless otherwise specified.

(Production of curable composition)
Raw materials of the types shown in Table 1 were stirred and mixed with the compositions shown in Table 1 to prepare a curable composition, and the gelling time and surface curing time of the obtained curable composition were measured. Table 1 shows the results. As the component (1-1), bisphenol A type ethylene oxide-modified dimethacrylate (in the general formula (A), R ₁ and R ₁ ′ are methyl groups, R ₂ and R ₂ ′ are ethylene groups, and m + n = 4) And dicyclopentenyloxyethyl methacrylate as component (1-2), 2-hydroxyethyl methacrylate as component (1-3), and 1,1,3,3-tetramethylbutyl as component (2). Hydroperoxide and cobalt octylate were used as the component (3). Paraffin wax (melting point 46 ° C.) and paraffin wax (melting point 57 ° C.) were used as paraffin, hydroquinone as a polymerization inhibitor, and cumene hydroperoxide as other control organic peroxide.

(Method of measuring gel time)
The time until the curable composition gelled was measured. 50 g of a two-part curable resin composition aged 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 Co., Ltd.) was inserted, and the temperature change was measured at one-minute intervals. The time from when the curable composition was mixed until the exothermic peak was shown was defined as the gel time, and is shown in Table 1 in minutes.

(Method of measuring surface hardening time)
When the curable composition was applied in the form of a thin film, the time until the surface of the coating film was cured was measured. In a 23 ° C. environment, a curable composition was weighed onto a mortar test plate (dimensions: 10 mm × 70 mm × 150 mm) prepared by a method specified in JIS R 5201: 2015 so that the coating amount was 0.2 kg / m ^2. The sample was applied with a brush while preparing a test sample. The test specimen was allowed to stand still in an environment of 23 ° C., and after a certain time described later, the surface of the coating film was touched with a fingertip, and the time until the tackiness disappeared was defined as a surface hardening time.

  In general, the rate of the polymerization reaction depends on the type of the initiator and the 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 conventional technology, in order to slow down the polymerization reaction assuming use in a high-temperature environment, the activity is reduced by changing the type of organic peroxide, or the amount of organic peroxide is reduced. And the polymerization reaction of (meth) acrylate. However, in parallel with this, for the reaction in which the polymerization is inhibited by oxygen and dissolved oxygen in the air, the activity of the organic peroxide decreases, or the amount of the organic peroxide decreases and the radical concentration decreases, There is a problem that the effect of polymerization inhibition by oxygen becomes large, and the curability of the protruding portion, the coating film surface, and the like is reduced. The present inventors have conducted intensive studies and have found that the use of an organic peroxide having a one-hour half-life temperature of 90 to 185 ° C. reduces the influence of polymerization inhibition by oxygen while adjusting the polymerization reaction of (meth) acrylate. A curable composition having good surface curability was found.

  Furthermore, among the organic peroxides having a one-hour half-life temperature of 90 to 185 ° C., those having a high symmetry, the radicals generated are generated in parallel with the polymerization reaction with (meth) acrylate (meth). ) By efficiently reacting with the dissolved oxygen in the acrylate liquid, the concentration of dissolved oxygen in the system is reduced, and it is presumed that the polymerization proceeds rapidly to near the surface of the coating film. Conceivable. As such an organic peroxide, for example, 1,1,3,3-tetramethylbutyl hydroperoxide having high symmetry in a 1,1,3,3-tetramethylbutyl structure can be given.

The use of a curable composition having a long gelation time, excellent handling properties, and good surface curability has the following excellent effects particularly in the repair of a structure under the atmosphere. The applicability is great.
(1) Since the gelation time of the curable composition can be secured for 60 minutes or more, manual mixing and coating can be performed.
(2) The curable composition does not need to be cooled and used, and the season and region in which the curable composition is used are not easily restricted, and repair under a wide range of environmental conditions is possible.
(3) The surface hardens within 6 hours after application of the curable composition, leading to a shortened construction period in repair work, which is efficient.

Claims (6)

(1) mixing (meth) acrylate, (2) an organic peroxide having a one-hour half-life temperature of 90 to 185 ° C., and (3) a curing accelerator to obtain a curable composition;
Applying the obtained curable composition to a structure. The curable composition is a two-part composition, wherein the first part contains at least (2) an organic peroxide having a one-hour half-life temperature of 90 to 185 ° C, and the second part contains at least (3) ) Containing a curing accelerator,
The curable composition is cured within 6 hours after mixing the first agent and the second agent, and the first agent and the second agent until the curable composition gels. The method according to claim 1, wherein it takes 60 minutes or more after mixing.   (2) The repair method according to claim 1 or 2, wherein the organic peroxide having a one-hour half-life temperature of 90 to 185 ° C contains 1,1,3,3-tetramethylbutyl hydroperoxide.   The curable composition contains (1) 100 parts by mass of (meth) acrylate and (2) 0.1 to 10 parts by mass of an organic peroxide having a one-hour half-life temperature of 90 to 185 ° C. The repair method according to any one of claims 1 to 3.   The repair method according to any one of claims 1 to 4, wherein the step of applying the obtained curable composition is performed in the atmosphere.   A structure repaired by the repair method according to claim 1.