JPH10237264A - Grout for concrete structure and method of repairing the structure by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grout which is remarkably improved in flowability and can easily be penetrated into the voids of a cement structure, by using as the constituent an acrylic micro-polymer emulsion having a mean particle diameter for 30-200nm and obtained by the emulsion polymerization of a (meth) acrylic ester and at least one unsaturated monomer having at least one organic group selected from a carboxyl (carboxylate) group and a sulfo (sulfonate) group, and provide a method of repair by using the grout. SOLUTION: The acrylic micro-polymer emulsion is an emission containing a core-shell type heterogeneous layered acrylic micro-polymer emulsion, wherein the shell part of the microparticle comprises a copolymer obtained by the emulsion polymerization of a monomer mixture containing an unsaturated (meth) acrylic ester monomer, an unsaturated monomer having carboxyl (carboxylate) groups, and an unsaturated monomer having sulfo (sulfoante) groups. The grout 30 is injected into the hair crack 32 of a concrete structure 31 by using an injection gun 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete structure injection material used for repairing a crack in a concrete structure and a repair method using the same. For more information,
The present invention relates to an injection material for concrete structures which can be suitably used for repairing a so-called hairline crack having a crack width of about 0.2 mm or less, and a repair method using the same.

[0002]

2. Description of the Related Art Eliminating cracks in concrete structures is an eternal theme. This problem has become more acute in the context of recent concrete trends, which tend to increase the amount of cement to increase concrete strength. When a structural crack is generated outside, water penetrates into the crack and causes collapse (efflorescence, hereinafter sometimes abbreviated as “Efro”). That is, water such as rainwater is generally carbon dioxide (CO ₂ )
It is acidic including sulfuric acid (H ₂ SO ₄ ) or nitric acid sometimes. When such acidic water penetrates into the hairline crack of concrete, it dissolves calcium (Ca), etc., which is an alkaline substance in the concrete, elutes on the concrete surface in this state, and the moisture is dried, and Ca etc. becomes solid. It is a phenomenon that is accumulated on the concrete surface. It is similar to the principle of stalactite formation. This not only affects the strength of the structure in the long run, but also significantly impairs its appearance. Therefore, various repair methods have been conventionally proposed. In particular, it was difficult to repair so-called hairline cracks having a crack width of about 0.2 mm or less. The most common repair method for hairline cracks is a method of cutting, hanging or drilling hairline cracks, and filling the hairline cracks with resin. However, this method has a problem in that cutting, hanging, or drilling work is required, which requires man-hours, time, and cost. In order to improve this problem, a method has been proposed in which a specific resin sealing liquid is filled in a cartridge and injected into a hairline crack without V-cut (Japanese Patent Laid-Open No. 24366/1992).

[0003]

However, according to the method disclosed in the above-mentioned conventional Japanese Patent Application Laid-Open No. 4-24366, the injection material has a high viscosity of, for example, 1000 cps or more, has poor fluidity, and penetrates into narrow voids of the cement structure. However, there is a problem that it is difficult to efficiently repair hairline cracks because of the difficulty.

[0004] The present invention solves the above-mentioned conventional problems, has good fluidity, can easily penetrate into the voids of the cement structure, and can efficiently repair even small hairline cracks. It is possible to obtain a stable workability irrespective of the working conditions, and to reduce the fluidity due to temperature change, and to finely disperse the cement composition particles in the cement slurry. In addition, the present invention provides an injection material for a concrete structure having improved bending strength and a repair method using the same.

[0005]

In order to achieve the above-mentioned object, an injection material for concrete structure of the present invention has at least one organic group selected from a carboxylic acid (salt) group and a sulfonic acid (salt) group. The composition includes an acrylic micropolymer emulsion having an average particle diameter of 30 nm to 200 nm obtained by emulsion polymerization of one or more unsaturated monomers and (meth) acrylic acid ester.

In the injection material, the acrylic micropolymer emulsion has an average particle diameter of 30 nm to 20 nm.
An emulsion containing a core-shell type layered acrylic micropolymer emulsion having a thickness of 0 nm, wherein said core particle of said core-shell type layered acrylic micropolymer emulsion has a (meth) acrylate unsaturated monoester. It is preferably a copolymer obtained by emulsion polymerization of a monomer mixture containing a monomer, a carboxylic acid (salt) group-containing unsaturated monomer, and a sulfonic acid (salt) group-containing unsaturated monomer. .

In the above-mentioned injection material, it is preferable that the microparticle shell of the core-shell type hetero-layered acrylic micropolymer emulsion contains a crosslinked acrylic polymer. In the injection material, the acrylic micropolymer emulsion is an aqueous dispersion, and the ratio of the acrylic micropolymer is 30% by weight in terms of solid content.
To 70% by weight, and the proportion of water is 70% to 3% by weight.
It is preferably in the range of 0% by weight. This is because the stability as an emulsion and the viscosity are kept low. A more desirable ratio of the acrylic micropolymer is in the range of 30% by weight to 50% by weight. Further, in the injection material, a hydraulic composition may be further contained in the acrylic micropolymer emulsion. Here, the hydraulic composition refers to, for example, cement and the like.

[0008] Next, the method for repairing a concrete structure according to the present invention is to repair and inject the above-mentioned injection material for a concrete structure into a hairline crack generated in the concrete structure without cutting, hanging or drilling. Features. The above-described injection material of the present invention can also be used after being filled in a cartridge. Further, the cartridge can be used by being mounted on an injection gun.

[0009]

According to a preferred embodiment of the present invention described above, there is provided a core-shell type hetero-layered acrylic micropolymer emulsion having an average particle diameter of 30 nm to 200 nm, wherein the shell portion of the emulsion particles is provided. Prepares an emulsion composed of a copolymer obtained by emulsion polymerization of a predetermined monomer mixture such as a (meth) acrylate unsaturated monomer, and adds the emulsion as it is or to a cement slurry Thereby, the filling rate of the cement slurry can be increased, the change in the flow characteristics of the cement slurry due to the temperature change can be prevented, and the obtained cement slurry can form a hardened body having high strength. The reason why the polymer emulsion exerts such an effect is that the microparticles of the polymer emulsion are stably dispersed by the steric repulsion effect of the cement composition particles, so that the viscosity of the cement slurry is remarkably improved, and the open particle size asphalt is reduced. This is because the filling rate of the mixture into the voids is improved. Also, since the cement particles are finely dispersed,
This is because the hydration reaction is efficiently promoted, and the obtained cured product has a dense structure, and various properties such as compressive strength, bending strength, and wear resistance are improved.

Therefore, a preferred embodiment of the present invention is:
A polymer emulsion for an injection material for a cement structure, comprising a core-shell type layered acrylic micropolymer emulsion having an average particle diameter of 30 nm to 200 nm, wherein the core-shell type layered acrylic micropolymer emulsion ( The shell portion of the microparticles of the core-shell type emulsion is hereinafter referred to as a (meth) acrylate unsaturated monomer, a carboxylic acid (salt) group-containing unsaturated monomer and a sulfonic acid (salt) group-containing unsaturated monomer. Polymer for injection material for cement structure composed of a copolymer obtained by emulsion polymerization of a monomer mixture containing a saturated monomer and, if necessary, a hydroxyl group-containing unsaturated monomer. It is an emulsion. Since the shell part (surface part) of the emulsion is water-soluble, the shell part (surface part) easily penetrates and adheres to the concrete surface, and after adhering, moisture is adsorbed by the concrete and the core part of the emulsion is exposed.
In addition, since the average particle diameter is small, it can easily penetrate into small gaps. Furthermore, the core part (center part) of the emulsion
Since it is oily, it adheres to the concrete surface and forms a film to exhibit water repellency. This makes it possible to keep the hairline crack surface water-repellent, prevent further penetration of rainwater, and prevent efflorescence. Hereinafter, the present invention will be described in detail.

First, in the present invention, the copolymer forming the microparticle shell will be described. When forming the microparticle shell portion, the monomer is not particularly limited as long as it is a monomer that forms a micropolymer emulsion that stably disperses the cement particles and improves the strength of the cured cement slurry. Acid ester unsaturated monomers, carboxylic acid (salt) group-containing unsaturated monomers, sulfonic acid (salt) group-containing unsaturated monomers, and hydroxyl group-containing unsaturated monomers can be used.

Examples of the (meth) acrylate unsaturated monomer used in the present invention include methyl acrylate,
Ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, alkyl acrylates having an alkyl group having 1 to 8 carbon atoms such as octyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, etc. There are alkyl methacrylates having 1 to 8 carbon atoms in the alkyl group, and these esters can be used alone or in combination of two or more. If the alkyl group in these esters has more than 8 carbon atoms, the copolymerizability with other unsaturated monomers will be poor, and a desired polymer emulsion cannot be obtained.

The unsaturated monomer (meth) acrylate is the remainder of the copolymer constituting the shell of the microparticle except for the other unsaturated monomer and the crosslinking agent,
Therefore, it is appropriate to contain 60 to 99.8% by weight, preferably 79 to 98.4% by weight. When the alkyl acrylate containing a C ₁ -C ₈ alkyl group and the alkyl methacrylate containing a C ₁ -C ₄ alkyl group are used in combination, the former constituting the copolymer constituting the microparticle shell portion may be used. The ester is 0.
Suitably, it is 1 to 49.8% by weight, preferably 10 to 40% by weight, and the latter ester is 50.0 to 99.7% by weight, preferably 60 to 90% by weight.

In order to carry out the present invention more effectively,
In the (meth) acrylic acid ester unsaturated monomer, the glass transition temperature (hereinafter referred to as Tg) obtained from the Fox formula (Equation 1) shown below is 285 to 335 ° K.
Is preferable, and the temperature is particularly preferably 300 to 320 ° K. The reason for limiting the value of Tg in this way is that 28
If the temperature is lower than 5 ° K, the viscosity of the cement slurry is affected by the temperature, which is not preferable. If the temperature is higher than 335 ° K, the film-forming property is deteriorated.

[0015]

(Equation 1)

Examples of the unsaturated monomer having a carboxylic acid (salt) group (hereinafter referred to as a carboxylic acid group-containing unsaturated monomer) used in the present invention include acrylic acid, methacrylic acid and crotonic acid. Monocarboxylic acids and salts thereof,
Examples include dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, and half esters or half amides thereof, and salts thereof, and methacrylic acid is particularly preferable. In the polymer emulsion of the present invention, the carboxylic acid group-containing unsaturated monomer plays a role of stabilizing the cement slurry by a steric repulsion effect.

The unsaturated monomer having a carboxylic acid group is contained in the copolymer constituting the microparticle shell portion in an amount of 0.1 to 15%.
%, Preferably 0.5 to 10% by weight, particularly preferably 0.5 to 6% by weight. When the content in the copolymer is limited as described above, the stabilization effect of the cement slurry is not seen when the content is less than 0.1% by weight, and the hydration reaction of the cement slurry is inhibited when the content exceeds 15% by weight. And adversely affect the curing reaction.

Examples of the unsaturated monomer having a sulfonic acid (salt) group (hereinafter, referred to as a sulfonic acid group-containing unsaturated monomer) used in the present invention include styrene sulfonic acid and α-styrene.
Methylstyrenesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, 2-methacrylamide-2-methylpropanesulfonic acid, 2-acrylamide-2-butanesulfonic acid, 2-acrylamide-2-sulfonic acid and salts thereof And the like. Particularly preferred is
2-acrylamido-2-methylpropanesulfonic acid. The role of the sulfonic acid group-containing unsaturated monomer is not fully understood, but by adding the unsaturated monomer, cement particles are finely dispersed in a cement slurry, and the structure of the slurry cured body is reduced. It is considered to be dense and improve the strength.

The sulfonic acid group-containing unsaturated monomer is contained in the copolymer constituting the microparticle shell portion in an amount of 0.1 to 10%.
%, Preferably 0.1 to 6% by weight, particularly preferably 0.5 to 3% by weight. When the content is limited as described above, if it is less than 0.1% by weight, the fine dispersion effect of the cement is not observed. If it exceeds 10% by weight, the fine dispersion of the cement particles in the cement slurry proceeds. This is because the slurry viscosity is undesirably increased.

Examples of the unsaturated monomer having a hydroxyl group (hereinafter, referred to as hydroxyl group-containing unsaturated monomer) used in the present invention include allyl alcohol, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate. , 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, monoallyl ether of polyhydric alcohol, N-methylol acrylamide, N-methylol methacrylamide, etc., with N-methylol acrylamide being particularly preferred. The acrylic micropolymer particles of the present invention containing the unsaturated monomer lower the viscosity of the cement slurry, thereby improving the penetration of the cement slurry into the cement structure.

The hydroxyl group-containing unsaturated monomer includes:
0 to 10% by weight, preferably 0.5 to 6% by weight, preferably 0.5% by weight in the copolymer constituting the microparticle shell portion.
Suitably, it is contained up to 3% by weight. The upper limit of the content of the unsaturated monomer is specified because if it exceeds 10% by weight, the hydrophilic-hydrophobic balance of the surface of the acrylic micropolymer particles is lost, and the viscosity of the cement slurry is increased.

In the present invention, non-acrylic monomers such as styrenes such as styrene and α-methylstyrene, dienes such as butadiene and isoprene, and the like, as long as the performance of the acrylic micropolymer emulsion is not impaired. Vinyl esters such as vinyl acetate and vinyl propionate, and nitriles such as acrylonitrile and α-methylacrylonitrile can be added. The content of these monomers is preferably 0 to 20% by weight in the copolymer constituting the microparticle shell.

Furthermore, in the present invention, in order to improve the performance of the cured cement slurry, it is preferable to use a crosslinking agent having a plurality of functional groups in one molecule. Examples of these crosslinking agents include trimethylolpropane trimethacrylate, glycidyl acrylate, glycidyl methacrylate, bisphenol A polyoxyethylene adduct di (meth) acrylate, triallyl isocyanurate, and N-methylol (meth) acrylamide. Particularly, trimethylolpropane trimethacrylate is preferred. The content of the crosslinking agent is suitably 0 to 5% by weight, preferably 0.1 to 1% by weight in the copolymer constituting the shell of the microparticles. The reason why the upper limit of the amount used is set to 5% by weight is that if the amount exceeds 5% by weight, the polymerization stability becomes poor when preparing the polymer emulsion, and the film formability of the obtained polymer emulsion deteriorates. Because you do.

The copolymer constituting the microparticle core of the core-shell emulsion of the present invention is also an acrylic polymer. As the monomer constituting the copolymer, the same monomer as the alkyl (meth) acrylate constituting the shell of the microparticle of the present invention can be used. The Examples of the composition of the copolymer constituting the microparticle core unit, C ₁ -C ₈ 55-99.8 wt% acrylic acid alkyl ester containing an alkyl group, preferably 70-9
0 wt%, and C ₁ -C from 0.1 to 44.9 wt% methacrylic acid alkyl esters containing _alkyl group, preferably 10 to 30 wt%, a crosslinking agent 0-5% by weight, preferably 0 0.1-1% by weight.

In order to carry out the present invention more effectively,
In the (meth) acrylic acid ester unsaturated monomer, the glass transition temperature (hereinafter referred to as Tg) determined from the Fox equation is preferably 285 ° K or less, particularly preferably 248 ° K or less. . The reason why the upper limit of Tg is limited in this way is that if the temperature is higher than 285 K, the film-forming property is reduced.

In the present invention, non-acrylic monomers such as styrenes such as styrene and α-methylstyrene, dienes such as butadiene and isoprene, and the like, as long as the performance of the acrylic micropolymer emulsion is not impaired. Vinyl esters such as vinyl acetate and vinyl propionate, and nitriles such as acrylonitrile and α-methylacrylonitrile can be added. The content of these monomers is preferably 0 to 40% by weight in the copolymer constituting the microparticle core.

The weight ratio of the copolymer forming the core-shell type hetero-layered structure in the core portion and the shell portion is 2/3.
２７27/3, preferably 3/3 to 12/3. The reason for limiting the weight ratio of the copolymer of the core portion and the shell portion is that when the ratio of the shell portion is increased and the weight ratio of the core portion / shell portion is smaller than 2/3, the performance of the core portion is reduced. Is not reflected in the polymer emulsion particles, and the film formability is deteriorated. On the other hand, when the ratio of the core portion is increased and the weight ratio is larger than 27/3, the performance of the shell portion is not reflected, and the cement slurry is not reflected. The reason for this is that the viscosity increases and the fluidity decreases due to a change in temperature. In the present invention, an anionic emulsifier and a nonionic emulsifier for emulsion polymerization are used for preparing an acrylic micropolymer emulsion. Next, representative emulsifiers used in the present invention will be described.

[Anionic emulsifier] (1) Polyoxyalkylene alkylaryl ether sulfonate sulfate salt of formula (1)

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(2) Polyoxyalkylene alkyl ether sulfate salt of the formula (2)

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(3) Polyoxyethylene alkylaryl ether ether salt of the formula (3)

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(4) Compound of formula (4)

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(5) Compound of formula (5)

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(6) Compound of formula (6)

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(7) Compound of formula (7)

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(8) Compound of formula (8)

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(9) Compound of formula (9)

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[Representative Examples of Nonionic Emulsifiers] (10) Polyoxyalkylene alkyl aryl ether of formula (10)

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(11) Polyoxyalkylene alkyl ether of the formula (11)

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These anionic emulsifiers and nonionic emulsifiers can be used alone or in combination of two or more. When used in combination, it is preferable to use one or more emulsifiers having ethylene oxide and propylene oxide groups in the molecule,
In particular, it is desirable to use one or more of the anionic emulsifier (1) and the nonionic emulsifiers (10) and (11). These emulsifiers are used in an amount of 0.5 to 15% by weight, preferably 1 to 10% by weight, based on the monomer mixture used for producing the copolymer.

Examples of the polymerization initiator used in the present invention include: hydrogen peroxide; a combination of hydrogen peroxide and a carboxylic acid such as tartaric acid, citric acid, and ascorbic acid; hydrogen peroxide and oxalic acid, sulfinic acid, and the like. Salts or oxyaldehydes; combinations of water-soluble iron salts and the like; peroxides such as persulfates, percarbonates and perborates; 2,2′-azobis (2-aminodipropane) and its salts, 2 There are water-soluble azo initiators such as 2,2'-azobis (N, N'-dimethylene-isobutylamidine) and its salts, and 4,4'-azobis (4-cyanovaleric acid) and its salts. Azo-based initiators are preferred. These polymerization initiators, based on the unsaturated monomer mixture constituting the core or shell of the present invention,
It is preferably used in the range of 0.1 to 3% by weight.

The core-shell type emulsion of the present invention comprises:
The emulsion is prepared by preparing an emulsion containing the microparticle core, and then forming a shell on the surface of the microparticle core. Preferred production methods include a monomer dropping method and a pre-emulsification method. In the monomer dropping method, first, an emulsifier is dissolved in an aqueous phase, added to a part of an unsaturated monomer mixture mainly composed of an acrylic monomer for core preparation, emulsified and solubilized, and then polymerization is started. Agent, and then the remaining unsaturated monomer mixture for core preparation is dropped for a predetermined time to form an emulsion containing microparticle cores.
The unsaturated monomer mixture for shell part preparation is added dropwise. Here, the composition of the monomer mixture for preparing the microparticle shell portion was determined to be 60% of the (meth) acrylate unsaturated monomer.
９９99.8% by weight, preferably 79-98.4% by weight,
The carboxylic acid (salt) group-containing unsaturated monomer is 0.1 to 15% by weight, preferably 0.5 to 10% by weight, and the sulfonic acid (salt) group-containing unsaturated monomer is 0.1 to 10% by weight. %, Preferably 0.1 to 6% by weight, the hydroxyl group-containing unsaturated monomer is 0 to 10% by weight, preferably 0.5 to 6% by weight,
And the amount of the crosslinking agent is 0 to 5% by weight, preferably 0.5 to 1% by weight. Further, the composition of the monomer mixture for preparing the microparticle core is adjusted so that the acrylate unsaturated monomer is 55 to 99.8% by weight, preferably 70 to 9% by weight.
0% by weight, 0.1% by weight of methacrylate unsaturated monomer
-44.9% by weight, preferably 10-30% by weight, and the crosslinker is 0-5% by weight, preferably 0.1-1% by weight.

In the pre-emulsification method, the unsaturated monomer mixture is previously mixed and emulsified with a part of the emulsifier and water used. Next, the remaining emulsifier is dissolved in the remaining aqueous phase, a part of the pre-emulsion containing the acrylic monomer for core preparation as a main component is added, and after uniform emulsification and solubilization, polymerization is started. An agent is added, and the remaining pre-emulsion for core preparation is dropped for a predetermined time to form an emulsion containing a microparticle core, and then,
The pre-emulsion for shell part preparation is added dropwise to obtain the desired micropolymer emulsion. Here, the composition of the monomer mixture for preparing the microparticle shell portion and the core portion has the same composition ratio as in the monomer dropping method, but in order to pre-emulsify the unsaturated monomer for shell portion preparation. The emulsifier used is 0.1 to 11% by weight, preferably 2 to 6% by weight, based on the unsaturated monomer in the shell portion, and the amount of water used is 20 to 100% by weight, preferably, in the unsaturated monomer in the shell portion. It is adjusted to be 20 to 50% by weight. The amount of the emulsifier used to obtain the pre-emulsion for preparing the core is 0.1 to 11% by weight, preferably 2 to 11% by weight, based on the unsaturated monomer in the core.
3% by weight, the amount of water used is 2
The content is 0 to 80% by weight, preferably 20 to 50% by weight.

The emulsion can be prepared by either the monomer dropping method or the pre-emulsification method. However, the pre-emulsification method is more preferable in order to reduce the amount of the copolymer adhering to a polymerization vessel or a stirring blade, which is a disadvantage of emulsion polymerization.

It should be noted that, when producing the core-shell emulsion of the present invention, it is preferable to carry out aging for several minutes after the completion of the polymerization of the core. The reason is that if the shell part is dropped immediately after the core part dropping, the unreacted core part unsaturated monomer and the shell part unsaturated monomer are mixed, and an intermediate composition layer of the core part and the shell part is generated. This is because the effect of the shell cannot be efficiently exhibited. However, if the ripening time is too long, the activity of the initiator may be reduced, resulting in poor polymerization of the shell part. Therefore, it is necessary to determine the ripening time in consideration of the half-life of the initiator.

In the polymer emulsion for an injection material for a cement structure of the present invention, it can be used in an amount of 30 to 70% by weight, preferably 30 to 50% by weight in terms of solid content. When the viscosity measured by a Brookfield viscometer is 10 to 500 cP, workability is improved. When the viscosity is low, the solid content may be 50% by weight or more.

The core-shell type emulsion of the present invention has an average particle size of 30 nm to 200 nm, preferably 30 nm.
To 150 nm, particularly preferably 30 to 100 nm. When the average particle size is larger than 200 nm, the total surface area of the polymer particles decreases, and the effect of each functional group such as a sulfonic acid (salt) group, a hydroxyl group, and a carboxylic acid (salt) group that modify the particle surface decreases. This is not preferable because it significantly lowers the fluidity of the cement slurry. On the other hand, if the average particle size is smaller than 30 nm, the viscosity of the resulting polymer emulsion increases, which causes inconvenience in handling during production and use, which is not preferable.

A mixture of the acrylic micropolymer emulsion of the present invention and a hydraulic composition can also be used as an injection material for concrete structures. When preparing a cement slurry using the acrylic micropolymer emulsion of the present invention, based on 100 parts by weight of the cement composition,
The solid content of the core-shell emulsion of the present invention is 0.5
The amount may be 10 to 10 parts by weight, preferably 2 to 7 parts by weight. When the solid content is less than 0.5 part by weight, the properties of the cement slurry are insufficient to improve the physical properties, and when it exceeds 10 parts by weight, the compressive strength is remarkably reduced, so that it is not practical.

Examples of hydraulic compositions (cement compositions) that can be used in the present invention include Portland cement, fly ash cement, silica cement, blast furnace cement, cements such as alumina cement and gypsum cement, and semi-hardened cements. There are gypsums such as water, dihydrate and hexahydrate gypsum, and cements are particularly preferable. In addition, the cements may be any of normal, fast-strength, fast-hardening, ultra-fast-hardening, and white.

Further, various additives can be added to the cement slurry prepared from the core-shell type emulsion and the cement composition of the present invention, if necessary.
Examples of the additives include silica fume, fly ash, blast furnace slag, fine sand, mica, stone powder, glass powder, aluminum powder, inorganic pigments and other cement admixtures; lignin sulfonic acid (salt), fatty acid (salt) , Higher fatty acid (salt), naphthalene sulfonic acid (salt), formalin condensate, aromatic aminosulfonic acid (salt) compound, polystyrene sulfonic acid (salt), poly (meth) acrylic acid (salt) compound, poly Alkylene glycol, methyl cellulose, hydroxyethyl cellulose, nitrite, 1-
There are chemical admixtures for cement such as hydroxyethane-1,1-diphosphonic acid (salt), organic pigments, AE agents, water reducing agents, fluidizing agents, defoamers, humectants, rust inhibitors, and coloring agents. These cement admixtures and chemical admixtures for cement may be separately added at the time of mixing. You may mix and use.

[0050]

Next, the present invention will be described in detail with reference to examples and comparative examples. Unless otherwise specified, parts and%
Are based on weight. [Preparation of Acrylic Micropolymer Emulsion (Injection Material)] (1) Acrylic Micropolymer Emulsion 1 A glass reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen inlet pipe, and a dropping funnel was charged as shown in Table 2 1.0 part of the emulsifier of composition No. 1 was added and dissolved together with 70.0 parts of water, and the air in the container was replaced with nitrogen gas. Polymer emulsion of Table 1
70.3 parts of the core unsaturated monomer mixture shown in No. 1, 2.1 parts of the emulsifier of composition No. 1 in Table 2, and 28.0 parts of water were emulsified and mixed,
Of these, 7.5 parts were added to the reaction vessel and the temperature was raised to 60 ° C. After raising the temperature, a solution containing 0.3 part of 2,2'-azobis (2-aminodipropane) dihydrochloride and 12.0 parts of water was added to the reaction vessel, and then the remaining unsaturated monomer in the core was added. The emulsion was continuously dropped into the reaction vessel over 90 minutes, and polymerization was carried out at 60 ° C. After completion of the dropwise addition, the mixture was aged at 60 ° C. for 5 minutes. Subsequently, 32.5 parts of the shell unsaturated monomer mixture shown in the polymer emulsion No. 1 of Table 1 and 0.9% of the emulsifier of the composition No. 1 shown in Table 2
Part and 10.0 parts of water were successively added dropwise over 30 minutes to a shell portion unsaturated monomer emulsion, and polymerization was carried out at 60 ° C. After completion of the dropwise addition, aging was performed at 60 ° C. for 1 hour to complete the polymerization reaction. After cooling the obtained polymer to room temperature, the solid content was reduced to 40%.
No. 1 acrylic micropolymer emulsion
And This acrylic micropolymer emulsion N
The viscosity of o.1 was in the range of 2-3 cps. This was used as an injection material for repairing hairline cracks generated in concrete structures. (2) Acrylic micropolymer emulsion No. 2 to N
o.5 An acrylic micropolymer emulsion No. 1 was prepared using the unsaturated monomers shown in Table 1 and the emulsifier shown in Table 2. Here, the amounts of the emulsifier and water distributed to the core portion and the shell portion were distributed according to the core / shell ratio. The viscosities of the acrylic micropolymer emulsions No. 2 to No. 5 were in the range of 2 to 3 cps. (3) Polymer emulsion No. 6 A commercially available SBR-based polymer emulsion (styrene-butadiene copolymer AI 40%) was used. (4) Polymer emulsion No. 7 A commercially available EVA-based polymer emulsion (ethylene-vinyl acetate copolymer AI 40%) was used.

[0051]

[Table 1]

[0052]

[Table 2]

The average particle size of the acrylic polymer emulsion was measured using a Coulter submicron particle analyzer (Coulter Mode N4, manufactured by US Electronics Co., Ltd.).
Was measured by

[Preparation of Polymer Cement Slurry] JI
The ordinary portland cement and the acrylic micropolymer emulsion shown in Table 1 were kneaded using a kneader specified in SR5201 (physical test method of cement) to prepare a polymer cement slurry. At this time, the polymer cement ratio (%) was adjusted to 25.0 and the water cement ratio (%) was adjusted to 33.0.

[Evaluation of fluidity of polymer cement slurry] The polymer slurry was evaluated for fluidity by measuring the following free flow value and flow time. Free Flow Value A flow value (mm) was measured 30 minutes and 1 hour immediately after the preparation of the polymer cement slurry according to JIS R5201. Flow time Standard of Japan Society of Civil Engineers [PC grout test method (JSCE-198
6)], the falling time (second) of the polymer cement slurry was measured using a J14 funnel.

[Evaluation of Cured Product Performance of Polymer Cement]
The polymer cement cured body measured the following performance,
evaluated. . The cured product was cured under a humid air condition at 20 ° C. and a relative humidity of 80%, and was then air-dried at 20 ° C. and a relative humidity of 65% for 26 days. Compressive strength, thermoelastic coefficient Standard of Japan Society of Civil Engineers [PC grout test method (JSCE-198
6)], and a compression strength test was performed. In addition, a wire strain gauge having a gauge length of 20 mm was attached to the height, the center, and a symmetrical position of the side surface of the test specimen for compressive strength test, the compressive strain was measured, and the thermoelastic coefficient was obtained. Compressive strength, tensile strain A tensile strength test was performed according to ASTM C190. A gauge length of 20 mm at the center of the stress concentration part of the specimen for tensile test
And a tensile strain was measured. Table 3 shows the above results.

From Table 3, it can be seen that the polymer cement slurries No. C1 to No. C5 of the present invention using the emulsions Nos. 1 to 5 have remarkably good fluidity and hardened body performance, and have been compared with those conventionally used. It can be seen that the physical properties of the polymer cements No. C6 to No. C7 using the emulsions No. 6 to No. 7 of the example were greatly improved.

[0058]

[Table 3]

[Repair of Hairline Cracks Generated in Concrete Structure] The hairline cracks of 0.1 to 0.2 mm generated on the condominium veranda, corridor, and roof shown in Table 4 were cut without V / U cuts. .1 to N
The emulsion of No. 7 and the cement slurries of Sample Nos. C1 to C7 were injected using the apparatus shown in FIGS.

FIG. 1 is a front view of an injection gun 1 which can be suitably used in the present invention. The injection gun 1 has a loading section 2 for loading a cartridge of an infusion solution. The loading section 2 has windows 3, 3 'for observing the liquid inside the cartridge, and a fixing section for fixing the cartridge to the gun body. A fixing section 4 is provided. The injection gun 1 also includes a fixed grip 6 and a trigger 7 for holding by hand.
The one-way fixing unit 12 sends the shaft 5 forward by the length of the stroke (for example, 1 cm). As a result, the shaft 5 described later
The extruded part at the tip of the cartridge is sent forward, and the injection liquid is discharged from the nozzle 25 at the tip of the cartridge. Reference numeral 8 denotes a stopper releasing portion for pulling the shaft 5 to the right, which is normally pressed to the right by a spring 9 to fix the shaft, but necessary for loading the cartridge. Reference numeral 10 denotes a spring for applying a constant force to the trigger portion 7. Reference numeral 11 denotes a connection unit for connecting a cartridge. Note that the right end of the shaft 5 is bent so that it can be easily pulled on a finger.

FIG. 2 is an explanatory diagram for loading the injection liquid cartridge 20 into the injection gun 1. First, the shaft 5 is pulled to the right end while the stopper release portion 8 of the injection gun 1 is pressed by hand. In this state, the extruded portion 13 at the left end of the shaft 5
Is in the most retracted position. That is, the shaft 5 'is the shortest. Next, the injection liquid cartridge 20 provided with the injection nozzle 25 at the distal end portion 24 and the movable packing 22 having the seal portions 23 and 23 ′ at the bottom portion is put into the loading portion 2, and is connected to the connection portion 11 of the gun 1. By inserting and rotating the fixing portions 4 and 4 ', the whole is integrated. 21
Is a body part of the infusion solution cartridge 20.

Next, FIG. 3 shows that the cartridge 20 is
FIG. 3 is a partially cut-away view showing a state where the push-out unit 13 has been pushed into the tip end of the movable packing 22 as a whole and integrated with the gun 1. Next, FIG. 4 is a front view of the cartridge 20. Before use, a cap 26 is attached to the distal end 24 of the cartridge 20 and hermetically sealed. In addition, a movable packing 22 is provided on the bottom part, and is similarly sealed.

Next, FIG. 5 is an explanatory view showing a portion where a hair crack of a concrete structure is actually repaired by using the injection gun 1. The injection liquid 1 of the present invention is injected into the hair crack 32 of the concrete structure 31 using the injection gun 1.
Inject by.

The injection properties (workability) of the emulsion and the polymer cement slurry and the follow-up after half a year from the injection were visually evaluated for waterproofness, re-generation of Eflo, and the like. Table 4 shows the results. Sample Nos. 1 to 5 and Sample Nos. C1 to C5 are examples of the present invention, and Sample Nos. 6 to 7 and Sample Nos. C6 to C7 are comparative examples. Table 4 also confirms that the acrylic micropolymer emulsion and the polymer cement slurry of the present invention are suitable for repairing hair cracks in concrete structures, and that the method according to the present invention is effective for repair work.

[0065]

[Table 4]

As described above, according to the embodiment of the present invention, since the injection liquid of the present invention has a low viscosity, it penetrates to cracks in small gaps and can be repaired efficiently. In addition, there was little decrease in fluidity due to temperature change, and stable workability was obtained irrespective of construction conditions.

[0067]

As described above, the polymer slurry prepared using the polymer emulsion for cement structure of the present invention has remarkably improved fluidity and can be easily penetrated into the voids of the cement structure. In addition, since there is little decrease in fluidity due to a temperature change, stable workability can be obtained regardless of construction conditions. Furthermore, since the cement composition particles in the cement slurry are finely dispersed, the compressive strength and bending strength of the obtained hardened slurry are improved.

[Brief description of the drawings]

FIG. 1 is a front view of an injection gun according to an embodiment that can be suitably used in the present invention.

FIG. 2 is an explanatory view for loading an infusion liquid cartridge of one embodiment that can be suitably used in the present invention into an infusion gun.

FIG. 3 is a partially cutaway view of an injection gun according to an embodiment that can be suitably used in the present invention.

FIG. 4 is a front view of a cartridge according to an embodiment that can be suitably used in the present invention.

FIG. 5 is an explanatory view showing a part where a hair crack of a concrete structure is actually repaired by using the injection gun of one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection gun 2 Loading part 3, 3 'window part 4 Fixed part 5, 5' shaft 6 Fixed holding part 7 Trigger part 8 Stopper release part 9, 10 Spring 11 Connection part 12 One-way fixed part 13 Extruded part 20 Injection liquid cartridge DESCRIPTION OF SYMBOLS 21 Body part of cartridge 22 Moving packing 23 23 'seal part 24 Tip part 25 Injection nozzle 26 Cap 30 Injection liquid 31 Concrete structure 32 Hair crack

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Morita 1-3-7 Honcho, Sumida-ku, Tokyo Inside Lyon Co., Ltd. (72) Inventor Takashi Yoshida 26, Sakuragicho, Hirano, Kita-ku, Kyoto, Kyoto Prefecture

Claims (6)

[Claims] 1. An emulsion polymerization of at least one unsaturated monomer having at least one organic group selected from a carboxylic acid (salt) group and a sulfonic acid (salt) group with a (meth) acrylic ester. Average particle diameter of 30 nm to 2
An injection material for concrete structures containing an acrylic micropolymer emulsion of 00 nm. 2. The emulsion according to claim 1, wherein the acrylic micropolymer emulsion comprises a core-shell type layered acrylic micropolymer emulsion having an average particle diameter of 30 nm to 200 nm. The shell portion of the microparticle of the polymer emulsion contains a monomer containing a (meth) acrylate unsaturated monomer, a carboxylic acid (salt) group-containing unsaturated monomer, and a sulfonic acid (salt) group-containing unsaturated monomer. The injection material for concrete structures according to claim 1, which is a copolymer obtained by emulsion polymerization of a monomer mixture. 3. The injection material for concrete structure according to claim 2, wherein the microparticle shell portion of the core-shell type layered acrylic micropolymer emulsion contains a crosslinked acrylic polymer. 4. The acrylic micropolymer emulsion is an aqueous dispersion, wherein the proportion of the acrylic micropolymer is in the range of 30% by weight to 70% by weight in terms of solid content, and the proportion of water is 70% by weight to 30% by weight. %.
4. The injection material for concrete structures according to any one of items 3 to 3. 5. An injection material for a concrete structure, which further comprises (a) the acrylic micropolymer emulsion according to any one of claims 1 to 4, and (b) a hydraulic composition. 6. A method for repairing a pouring material according to any one of claims 1 to 5, wherein the pouring material is injected into a hairline crack generated in the concrete structure without cutting, hanging or drilling. Repair method of concrete structure.