JP2011168440A - Method of protecting surface of concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of protecting the surface of a concrete structure by which the whole surface of the concrete having recessed parts or the projecting parts uniformly and easily coated and which does not need power, does not need strict measurement and mixture, and does not need specific material and equipment except for an aerosol product. <P>SOLUTION: In the method of protecting the surface of the concrete structure, a two component type (metha)acryl based curable composition comprising an aerosol A agent having a composition prepared by mixing a (metha)acryl based resin composition containing (metha) acrylic ester and an organic peroxide with a jetting agent as an aerosol and an aerosol B agent having a composition prepared by mixing a (metha) acryl based resin composition containing (metha) acrylic ester and a reducing material capable of degrading the organic peroxide with the jetting agent as an aerosol is blown on the surface of the concrete structure to obtain a cured coating film of the (metha) acryl based curable resin composition on the surface of the concrete structure. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a surface protection method for spraying a (meth) acrylic curable resin composition comprising two aerosols onto the surface of a concrete structure to form an organic coating on the surface of the concrete structure.

In the daily inspection, the concrete part of the tunnel is peeled off and peeled off unstable parts such as joints and junkers and small floats. However, the part once knocked down often becomes a part that needs to be knocked down again after the next inspection, and the range of the knocked down gradually increases. Therefore, if a strong adhesive can be applied to such locations, it is considered that a sufficient effect can be exerted for the present anti-peeling measures.
However, currently widely used countermeasures have the following problems.
(1) There are many cases where it is not possible to cope immediately even if a point requiring countermeasures is found by daily inspection.
(2) The handling of repair materials requires a certain level of expertise such as weighing, mixing, and application.
(3) In the case of using a commercially available repair material, in addition to a normal protective curing material, a measuring machine, a mixing machine, a mixing container, a roller, a brush, and the like are necessary, and a large amount of luggage is carried for inspection.
(4) Although spraying is preferable to apply the repair material evenly on the uneven surface, since it requires power, the cost for ordering the construction is high.

On the other hand, aerosols in which a large number of fine particles are floated in a gas are widely used in household products, paints, insecticides, industrial products, and the like.
And as a cement application surface protection reinforcement material containing a thickener, the cement spray coating material which uses aerosol is proposed by patent document 1. FIG.

  However, cement spray coating materials have the problem of contaminating the surrounding area with dust due to rebounding from the spray target, and are also included in the cement coated surface protection reinforcing material containing the thickener previously applied to the target. As a result, the degree of hydration and condensation of the cement spray coating material and the adhesion to the target are unstable.

Further, Patent Document 2 and Patent Document 3 are known as conventional techniques related to a curable resin composition comprising two aerosols filled with two reactive substances in different aerosol containers.
These are epoxy resins or urethane resins in which the curable resin composition is composed of a main agent and a curing agent, and the epoxy resin and the urethane resin are atomic groups involved in the polymerization reaction of each resin composition constituting the two components in the polymerization reaction. If the stoichiometric ratio is not matched to 1: 1, a tough cured product may not be obtained, and there is a problem that such an aerosol product is difficult to adjust.
Furthermore, if the respective curable resin compositions constituting the two components are not mixed uniformly, a non-cured part will be formed. Therefore, in addition to the aerosol product, a dedicated nozzle and a mixer are required. There was a need to wash.

There are Patent Document 4 and Patent Document 5 as techniques for aerosolizing (meth) acrylic resins.
These are aerosols of a polymer obtained by copolymerizing multiple types of (meth) acrylic acid ester, or a dissolved solution dissolved in an organic solvent or a turbid liquid dispersed in water. There was a problem that it was not high.

JP 2007-008801 A JP 49-051615 A Japanese Patent Application Laid-Open No. 07-313910 JP-A-60-137970 Japanese Patent Application Laid-Open No. 07-070531

  For peeling and peeling of concrete pieces from the surface of concrete structures, during daily inspections, unstable parts such as joints and junkers and small floats are knocked down, and then the surface is protected. An organic coating is formed on the surface to prevent further deterioration.

  In general, the organic coating film is formed by applying a room temperature curable two-component resin composition. The method mainly involves spraying and spraying a mixture of a room temperature curable two-component resin composition with (1) application with hair and rollers, (2) a high-pressure pump using power such as a compressor, and (3) Patent Document 1. The spraying by aerosol products as shown in ˜5.

  However, (1) Application with a brush or a roller is difficult to apply evenly over the entire surface, particularly in unstable parts of joints and junkers, and concrete concave parts and convex parts after being knocked down by small floats. The surface protection performance such as the neutralization prevention performance and chloride ion blocking performance of the concrete is not sufficient.

  In addition, (2) spraying and spraying with a high-pressure pump that uses power such as a compressor can be applied uniformly over the entire surface, such as concrete recesses and protrusions, but it requires power, so daily inspections are required. It is unsuitable for small-scale responses in Japan.

  Furthermore, (3) the aerosol products as disclosed in Patent Documents 1 to 5 have the problems described above.

  The present invention can easily apply uniform coating over the entire surface of the concave and convex portions of the concrete structure, does not require power, does not require strict metering and mixing, and is not limited to aerosol products. An object of the present invention is to provide a surface protection method in which an unnecessary (meth) acrylic curable resin composition composed of two aerosols is sprayed to form an organic coating on the surface of a concrete structure.

That is, the present invention relates to an aerosol A agent in which a composition obtained by mixing a (meth) acrylic resin composition containing a (meth) acrylic acid ester and an organic peroxide and a propellant is used as an aerosol, 2 agents comprising an aerosol B agent in which a composition obtained by mixing a (meth) acrylic resin composition containing an acrylic ester and a reducing substance capable of decomposing the organic peroxide and a propellant is used as an aerosol. A (meth) acrylic curable composition of a mold is sprayed onto the surface of a concrete structure to obtain a cured film of the (meth) acrylic curable resin composition on the surface of the concrete structure. It is a surface protection method, and the (meth) acrylic resin composition contained in the agent A and agent B has a viscosity measured under conditions of 23 ° C. and 20 min ⁻¹ based on JIS K 7117-1: 1999. 50-6,000mPa The method for protecting a surface of a concrete structure according to claim 1, wherein the propellant is dimethyl ether or liquefied natural gas. Is sprayed on the surface of the concrete structure first with the aerosol A agent, and then the aerosol B agent is sprayed on the surface of the concrete structure, or the aerosol B agent is sprayed on the surface of the concrete structure first, and then the aerosol A agent is sprayed thereon. Alternatively, the aerosol A agent and the aerosol B agent are simultaneously sprayed on the surface of the concrete structure, and the (meth) acrylic resin composition contained in the aerosol A agent and the aerosol B agent is collided and mixed to obtain a cured film. The surface protection method of the concrete structure to be A protection has been concrete structure.

  According to the present invention, for peeling or peeling off of concrete pieces from the surface of a concrete structure, instability, such as joints or junkers, and small floats are struck down during daily inspection. When forming an organic coating to protect the surface, it is easy to apply uniformly over the entire surface of concrete depressions and protrusions, etc., no power is required, strict weighing and mixing are not required, and other than aerosol products Can protect the surface by spraying a (meth) acrylic curable resin composition composed of two aerosols, which does not require materials and equipment, and forming an organic coating on the surface of the concrete structure.

  The present invention provides an aerosol A agent in which a (meth) acrylic resin composition (A agent) containing a (meth) acrylic acid ester and an organic peroxide is mixed with a propellant, a (meth) acrylic acid ester, A two-component (meth) acrylic curable composition comprising an aerosol B agent obtained by mixing a (meth) acrylic resin composition (agent B) containing a reducing substance capable of decomposing an organic peroxide with a propellant. This is a method for protecting the surface of a concrete structure sprayed with water.

  As the (meth) acrylic acid ester which is a component of the aerosol used in the method for protecting the surface of a concrete structure of the present invention, monofunctional (meth) acrylate containing one (meth) acrylic group in one molecule or 1 The polyfunctional (meth) acrylate which contains two or more (meth) acryl groups in a molecule | numerator is mentioned, These 1 type (s) or 2 or more types can be used.

Monofunctional (meth) acrylates include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) ) Acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, phenyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, methoxylation Cyclodecatriene (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydride Xylbutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, alkyloxypolyethylene glycol mono (meth) acrylate, alkyloxypolypropylene glycol mono (meth) acrylate, phenoxypolyethylene glycol mono (meth) acrylate , Phenoxy polypropylene glycol mono (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, glycidyl (meth) acrylate, caprolactone modified tetrahydrofurfuryl (meth) acrylate, 3-chloro 2-hydroxypropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) Acrylate, N, N-diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, morpholine (meth) acrylate, ethoxycarbonylmethyl (meth) acrylate, ethylene oxide modified phthalic acid (meth) acrylate, ethylene oxide modified succinic acid It has an allyl group such as (meth) acrylate, trifluoroethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, 2-hydroxy-3- (meth) acryloyloxypropyltrimethylammonium chloride, allyl (meth) acrylate (meta ) Acrylate and (meth) acrylate having a dicyclopentenyl group. Among these, 2-hydroxyethyl (meth) acrylate and / or dicyclopentenyloxyethyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate and dicyclopentenyloxyethyl (meth) acrylate are used in combination. Is more preferable. When used together, the mixing ratio is a mass ratio, preferably 2-hydroxyethyl (meth) acrylate: dicyclopentenyloxyethyl (meth) acrylate = 20-50: 80-50, more preferably 30-40: 70-60. .
Polyfunctional (meth) acrylates include polyethylene glycol di (meth) acrylate, polyglycerol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polybutylene glycol di (meth) acrylate, ethylene glycol di (meth) acrylate, Propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris (meth) acryloyloxyethyl isocyanurate, 2,2-bis (4- (me ) Acryloxyphenyl) propane, 2,2-bis (4- (meth) acryloxyethoxyphenyl) propane, 2,2-bis (4- (meth) acryloxydiethoxyphenyl) propane, 2,2-bis ( 4- (meth) acryloxypropoxyphenyl) propane, 2,2-bis (4- (meth) acryloxytetraethoxyphenyl) propane, epoxy (meth) acrylate, trade name “Biscoat # 540” (Osaka Organic Chemical Industry Co., Ltd.) Product name, “epoxy ester 3000M” (manufactured by Kyoeisha Chemical Co., Ltd.), polyester (meth) acrylate, product name “Aronix M-6100” (manufactured by Toagosei Co., Ltd.) and urethane (meth) acrylate, product name “Aronix M- 1100 "(manufactured by Toa Gosei Co., Ltd.), methacryl-modified liquid polybutadiene at both ends, trade name "TE-2000" (manufactured by Nippon Soda Co., Ltd.), both end acrylic modified liquid polyacrylonitrile butadiene, trade name "HycarVTBNX" (manufactured by Ube Industries), both end methacryl modified liquid partially hydrogenated polybutadiene, trade name "TEAI-1000" ( Nippon Soda Co., Ltd.), both-end acrylic modified liquid polybutadiene, trade name “BAC-45” (manufactured by Osaka Organic Chemical Co., Ltd.) and the like.
Among these, one or more of the group consisting of methacrylic modified liquid polybutadiene, epoxy (meth) acrylate, and ethylene glycol di (meth) acrylate at both ends are preferred, and methacrylic modified liquid polybutadiene and / or epoxy at both ends are preferred. (Meth) acrylate is more preferred.
In (meth) acrylic acid ester, it is preferable to use monofunctional (meth) acrylate and polyfunctional (meth) acrylate together. When used together, the mixing ratio is a mass ratio, and monofunctional (meth) acrylate: polyfunctional (meth) acrylate = 30 to 90:70 to 10 is preferable, and 40 to 80:60 to 20 is more preferable.

The viscosity of the (meth) acrylic resin composition is JIS K from the viewpoint of impregnation and film formation of the (meth) acrylic resin composition when the aerosol is sprayed and cured on the surface of the concrete structure.
7117-1: 1999 "Plastics-Liquid, emulsion or dispersion resin-Method of measuring apparent viscosity with Brookfield rotary viscometer", viscosity measured under conditions of 23 ° C and 20min ^-1 50 to 6,000 mPa · s is preferable, and 200 to 4,500 mPa · s is more preferable.
When the (meth) acrylic resin composition is sprayed at a viscosity of less than 50 mPa · s, the (meth) acrylic resin composition is almost impregnated and diffused into the concrete and does not coat the surface of the concrete structure. In addition to the risk of reducing the blocking properties of deterioration factors such as chlorinated compounds such as concrete and reinforcing bars, the spraying and spraying forms become mist-like, and the concrete surface is scattered for other than the intended purpose, surrounding contamination, and work. There is a risk of health damage due to contact with the elderly. If the (meth) acrylic resin composition exceeds 6,000 mPa · s, mixing of the A agent and the B agent may be insufficient.
Therefore, in order to set the viscosity of the (meth) acrylic resin composition to 50 to 6,000 mPa · s, it is preferable to use a plurality of (meth) acrylic acid esters by selecting a low viscosity compound and a high viscosity compound.

  The organic peroxide contained in the aerosol A agent of the present invention refers to what has a function of a so-called radical polymerization initiator, and examples thereof include the following, and use one or more of these. Can do.

  (1) Ketone peroxides: methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, methyl acetoacetate peroxide, and acetylacetone peroxide.

  (2) Peroxyketals: 1,1-bis (tertiary butyl peroxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tertiary butyl peroxy) cyclohexane, 2,2-bis ( Tertiary butyl peroxy) octane, normal butyl-4,4-bis (tertiary butyl peroxy) valerate, 2,2-bis (tertiary butyl peroxy) butane, and the like.

  (3) Hydroperoxides: Tertiary butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, and 1 1,3,3-tetramethylbutyl hydroperoxide and the like.

  (4) Dialkyl peroxides: ditertiary butyl peroxide, tertiary butyl cumyl peroxide, dicumyl peroxide, α, α'-bis (tertiary butyl peroxy-meta-isopropyl) benzene, 2,5-dimethyl -2,5-di (tertiary butyl peroxy) hexane, 2,5-dimethyl-2,5-di (tertiary butyl peroxy) hexyne-3, and the like.

  (5) Diacyl peroxides: acetyl peroxide, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide, laurinoyl peroxide, 3,3,5-trimethylhexanoyl peroxide, succinic acid peroxide, benzoyl Peroxide, 2,4-dichlorobenzoyl peroxide, meta-toluoyl peroxide and the like.

  (6) Peroxydicarbonates: diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, dinormalpropyl peroxydicarbonate, bis (4-tertiarybutylcyclohexyl) peroxydicarbonate, di-2 -Ethoxyethyl peroxydicarbonate, dimethoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, diallyl peroxydicarbonate, and the like.

  (7) Peroxyesters: tertiary butyl peroxyacetate, tertiary butyl peroxyisobutyrate, tertiary butyl peroxypivalate, tertiary butyl peroxyneodecanoate, cumyl peroxyneodecanoate, Tertiary butyl peroxy-2-ethylhexanoate, tertiary butyl peroxy-3,3,5-trimethylhexanoate, tertiary butyl peroxylaurate, tertiary butyl peroxybenzoate, ditertiary butyl peroxy Isophthalate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, tertiary butyl peroxymaleic acid, tertiary butyl peroxyisopropyl carbonate, cumyl peroxy Toeto, tertiary hexyl peroxyneodecanoate, tert-hexyl peroxypivalate, tert-butyl peroxy hexanoate, tertiary-hexyl peroxy hexanoate, and the like cumylperoxy neo hexanoate.

Among organic peroxides, hydroperoxides are preferable and cumene hydroperoxide is more preferable in that the decomposition rate at normal temperature is slow and the storage stability of the aerosol is excellent.
0.2-10 mass parts is preferable with respect to 100 mass parts of (meth) acrylic acid ester in A agent, and, as for the usage-amount of an organic peroxide, 0.5-3.0 mass parts is more preferable.

  The reducing substance capable of decomposing an organic peroxide contained in the aerosol B agent of the present invention is a compound that promotes the decomposition of the organic peroxide, and examples thereof include the following, Or 2 or more types can be used.

(1) Thiourea derivatives: diethylthiourea, dibutylthiourea, ethylenethiourea, tetramethylthiourea, mercaptobenzimidazole, benzoylthiourea and the like. (2) Amines: N, N-diethyl-p-toluidine, N, N-dimethyl-p-toluidine, N, N-diisopropanol-p-toluidine, triethylamine, tripropylamine, ethyldiethanolamine, N, N- Dimethylaniline, ethylenediamine, and triethanolamine. (3) Metal salt of organic acid: cobalt naphthenate, copper naphthenate, zinc naphthenate, cobalt octylate, iron octylate and the like. (4) Organometallic chelate compounds: copper acetylacetonate, titanium acetylacetonate, manganese acetylacetonate, chromium acetylacetonate, iron acetylacetonate, vanadyl acetylacetonate, cobalt acetylacetonate and the like.
In these, the transition metal salt and / or organic metal chelate compound of an organic acid are preferable at the point which can improve the adhesiveness to the cement concrete surface, The transition metal salt of an organic acid is more preferable, and cobalt octylate is more preferable.
The amount of the reducing substance that can decompose the organic peroxide is preferably 0.01 to 5.0 parts by mass, more preferably 0.5 to 2.0 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester in the agent B.

In addition, the (meth) acrylic resin composition, which is a component of the aerosol of the present invention, can contain a small amount of a polymerization inhibitor in order to improve its storage stability.
Examples of the polymerization inhibitor include methyl hydroquinone, hydroquinone, catechol, hydroquinone monomethyl ether, monotertiary butyl hydroquinone, 2,5-ditertiary butyl hydroquinone, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, 2,5. -Ditertiary butyl-p-benzoquinone, picric acid, phenothiazine, tertiary butyl catechol, 2-butyl-4-hydroxyanisole, 2,6-ditertiary butyl-p-cresol and the like. Of these, hydroquinone is preferred.
The amount of the polymerization inhibitor used is preferably 0.0001 to 1.0 part by mass and more preferably 0.001 to 0.1 part by mass with respect to 100 parts by mass of the (meth) acrylic acid ester in the agent A or the agent B.

  Furthermore, the (meth) acrylic resin composition which is a component of the aerosol has various elastomers, colorants, rust inhibitors, solvents, extenders and reinforcing materials that are generally used within the range not impairing the object of the present invention. Additives such as plasticizers, paraffins, thickeners, thixotropic agents, silane coupling agents, titanate coupling agents, chelating agents, dyes, pigments, flame retardants, surfactants, and thermoplastic polymers Can be contained.

  Examples of the propellant to be filled in the aerosol of the present invention include dimethyl ether and liquefied natural gas. The propellant is sealed in an aerosol container such as an aerosol can together with the (meth) acrylic resin composition, and sprayed and sprayed. It is a liquefied gas having a gauge pressure of 0.3 MPa at 20 ° C., which is a pressure source at the time.

The mixing ratio of the (meth) acrylic resin composition and the propellant contained in the aerosol A agent or the aerosol B agent is preferably 30 to 70% by mass: 70 to 30% by mass, and 40 to 60% by mass: 60 to 40% by mass. % Is more preferable. When the (meth) acrylic resin composition is less than 30% by mass, the (meth) acrylic resin composition that is a coating film forming component is small, the economy is inferior, and when it exceeds 70% by mass, the (meth) acrylic There is a possibility that the viscosity of the resin-based resin composition becomes too high, and spraying and spraying cannot be performed well.
The mixing ratio of the aerosol A agent and the aerosol B agent is quantitatively controlled by reducing the mass of the aerosol product before and after use, spraying time, etc., and can be used in the range of 2: 8 to 8: 2 by mass ratio. .

  There are the following three types of mixing methods of the two-component (meth) acrylic curable composition aerosol in the surface protection method of a concrete structure.

(1) Aerosol A agent is sprayed on the concrete structure surface first, then aerosol B agent is sprayed on it, and (meth) acrylic resin composition contained in Aerosol A agent or Aerosol B agent is collided and cured. A coating is obtained.
(2) Aerosol B agent is sprayed on the concrete structure surface first, then aerosol A agent is sprayed thereon, and (meth) acrylic resin composition contained in Aerosol B agent or Aerosol A agent is collided and cured. A coating is obtained.
(3) The aerosol A agent and the aerosol B agent are simultaneously sprayed on the surface of the concrete structure, and the (meth) acrylic resin composition contained in the aerosol A agent or the aerosol B agent is collided and mixed in the air to obtain a cured film. .

The time for spraying the aerosol B agent after spraying the aerosol A agent and the time for spraying the aerosol A agent after spraying the aerosol B agent are not particularly limited, but 0-6 About hours are preferred.
Moreover, it is preferable to spray the aerosol A agent and the aerosol B agent at right angles to the concrete structure surface from the surface which suppresses scattering to the circumference.

  The present invention will be specifically described below with reference to examples.

Experimental example 1
A (meth) acrylic resin composition containing (meth) acrylic acid ester, organic peroxide and polymerization inhibitor as shown in Table 1 and contained in agent A, (meth) acrylic acid ester, Six kinds of (meth) acrylic resin compositions containing a reducing substance and a polymerization inhibitor as shown in Table 1 and contained in the B agent were prepared.
A total of 12 types of these (meth) acrylic resin compositions and 50 parts by mass of propellant (i) were sealed in 180 ml in a 200 ml capacity aerosol can to make an aerosol product. -6 types of aerosols A of aerosol No. 1-6A and 6 types of aerosols B of aerosol No. 1-1B to aerosol No. 1-6B were obtained.
As shown in Table 3, aerosol A agent and aerosol B agent are combined, and three types of spraying methods are used, and aerosol A agent and aerosol B agent are mixed and sprayed, and the sprayed state, the state of coating on the concrete surface, and the aerosol product The film cured state of the (meth) acrylic curable composition encapsulated in was evaluated. The results are also shown in Table 3.
As the concrete to be sprayed, the type N300 (300 × 300 mm) of a pavement flat plate in a precast unreinforced concrete product specified in JIS A 5371 was used, and the surface was sandblasted. The test was conducted in an atmosphere at a temperature of 20 ° C. and a relative humidity of 60%.

<Materials used>
(Meth) acrylic ester a: methacryl-modified liquid polybutadiene at both ends, manufactured by Nippon Soda Co., Ltd., trade name “TE-2000”
(Meth) acrylic acid ester b: epoxy acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name “Biscoat # 540”
(Meth) acrylic acid ester c: 2-hydroxyethyl methacrylate, commercial product (meth) acrylic acid ester d: dicyclopentenyloxyethyl methacrylate, commercial product (meth) acrylic acid ester e: ethylene glycol dimethacrylate, commercial product Oxide: cumene hydroperoxide, manufactured by NOF Corporation, trade name “Park Mill H-80”
Reducing substance: Cobalt octylate, Commercial product polymerization inhibitor: Hydroquinone, Commercial product propellant A: Dimethyl ether, Commercial product

<Blowing method>
Spraying method α: Method α, aerosol A agent is first sprayed onto the surface of the concrete structure for 20 seconds, and then aerosol B agent is sprayed thereon for 20 seconds, and (meth) acrylic resin contained in aerosol A agent and aerosol B agent The composition is impact mixed to obtain a cured coating.
Spraying method β: Method β, aerosol B agent is first sprayed onto the surface of the concrete structure for 20 seconds, and then aerosol A agent is sprayed thereon for 20 seconds, and (meth) acrylic resin contained in aerosol B agent and aerosol A agent The composition is impact mixed to obtain a cured coating.
Spraying method γ: Method γ, aerosol A agent and aerosol B agent are simultaneously sprayed onto the concrete structure surface for 20 seconds, and the (meth) acrylic resin composition contained in aerosol A and aerosol B agent is collided in the air. Thus, a cured film is obtained.

<Evaluation method>
Viscosity: Measured spraying conditions at 23 ° C and 20min- ¹ based on JIS K 7117-1999, "Plastics-Resin in liquid, emulsion or dispersion-Measuring method of apparent viscosity with Brookfield rotary viscometer" Evaluation criteria: When the sprayed (meth) acrylic resin composition is remarkably mist and contaminates the periphery of the specimen, it is not possible, the sprayed (meth) acrylic resin composition is somewhat mist, or (meth) Because the viscosity of the acrylic resin composition is high, it is necessary to make the aerosol injection port close to within 20 cm from the concrete surface. The sprayed (meth) acrylic resin composition hardly becomes mist, and The case where spraying can be performed even if the spray port is separated from the concrete surface by 20 cm or more was considered good.
Evaluation criteria of film formation state: 7 days after spraying, the film formation of the (meth) acrylic resin composition sprayed onto a 300 × 300 mm concrete plate is less than 75% of the entire surface area, 75 % Or more and less than 90% is acceptable, and 90% or more is considered good.
Criteria for evaluating the cured film state: 7 days after spraying, the (meth) acrylic resin composition in the liquid state is not fully or partially cured at the part where the film is formed, and cannot be completely cured. The case of (tack-free) was considered good.
Comprehensive evaluation criteria: “No” in the above evaluation, “No”, “No”, “Yes”, and “Good” for all items.

  From Table 3, it can be seen that the viscosity of the (meth) acrylic resin composition encapsulated in the aerosol product is preferably 50 to 6,000 mPa · s, and within this viscosity range, mixing of the two aerosols of the present invention is 3 It has been found that different spraying methods are applicable.

Experimental example 2
In the proportion shown in Table 4, A agent No. 3A, B agent No. 3B and propellant were used, and 180 ml was sealed in an aerosol can with a capacity of 200 ml to obtain an aerosol product, and the aerosol A agent and aerosol B agent shown in Table 4 were obtained. It was. As shown in Table 5, an aerosol A agent and an aerosol B agent were combined, and the same test as in Experimental Example 1 was performed.
The aerosol was sprayed by method α. The results are also shown in Table 5.

<Materials used>
Propellant B: Liquefied carbon dioxide, commercial product

  From Table 5, the mixing ratio of the (meth) acrylic resin composition and the dimethyl ether of the propellant was found to be preferably 30 to 70 parts by mass of the (meth) acrylic resin composition and 70 to 30 parts by mass of the propellant. .

Experimental example 3
Commercially available room temperature curing type epoxy resin (main agent viscosity 800mPa · s for curing cracking application, hardener viscosity 600mPa · s, mass ratio specified by the manufacturer: main agent: hardener = 2: 1) As shown in Table 6, the curing agent (B agent) was filled in an aerosol can together with propellant A to obtain an epoxy resin main agent aerosol (3-1A) and an epoxy resin curing agent aerosol (3-1B).
As shown in Table 7, aerosol A agent and aerosol B agent were combined, and the aerosol was sprayed on the same pavement flat plate as in Experimental Example 1 by spraying method α. After 7 days of spraying, the adhesion strength of the coating to the concrete and the curing of the coating The condition was observed. The results are also shown in Table 7.
In addition, in spraying method (alpha), the spraying time of the aerosol A agent and the aerosol B agent was changed.

<Evaluation method>
Evaluation criteria for bond strength: Compliant with JSCE-K 531-1999, Japan Society of Civil Engineers standard, “Adhesion test method for surface coating materials”. Adhesion strength is 1.5N / mm ² or more. Adhesion strength is 1.5. The case where it was less than N / mm ² was made impossible. In addition, the adhesion strength is an average value of three measurement points. Evaluation standard of film cured state: 7 days after spraying, when a resin composition in a liquid state is present in which the film is completely or partially cured at a portion where the film is formed. The case where the whole was completely cured (tack-free) was considered good.
Comprehensive evaluation criteria: The case where there was an impossibility in the top two evaluations was judged as impossible, and the case where there was no impossibility was judged as good.

  From Table 7, the coating of the curable resin composition is completely cured even when the spraying amount of the aerosol A agent and the aerosol B agent is slightly shifted by the surface protection method of the concrete structure of the present invention, and the concrete adheres sufficiently. It has been confirmed that it has sex.

Experimental Example 4
A commercially available 10 x 10 x 60 cm curb concrete was ruptured by a bisection load using a tensile and compression test (Autograph AG-300KNG, manufactured by Shimadzu Corporation), and the irregularities of the fractured surface were checked daily. This was used in the following test, imitating the knock-off surface.
As the aerosol of the present invention, 1-3A and 1-3B shown in Table 3 were sprayed onto the concrete fracture surface by the spraying method α to obtain test specimens. As a comparative example, (meth) acrylic curable resin 3A and (meth) acrylic curable resin 3B shown in Table 1 are weighed and mixed at a mass ratio of 3A: 3B = 1: 1, and 0.2% with respect to the concrete fracture surface. Rollers were applied at a coating weight of kg / m ² to obtain test specimens.
Seven days after spraying or roller coating, the test specimens were carbon dioxide under the conditions of carbon dioxide gas / 5%, atmospheric pressure / 1 atm, temperature / 20 ° C., relative humidity / 60% so that the spraying surface or roller coating surface would be upward. It was placed in a gas tank and allowed to stand for 30 days.
Thereafter, the test specimen was taken out from the carbon dioxide tank, cut with a diamond cutter in a direction perpendicular to the sprayed surface or the roller coated surface, and the cut surface was thoroughly washed with running tap water and dried for 24 hours. Thereafter, an alcohol solution of 1% phenolphthalein was sprayed on the cut surface, and the degree of neutralization by carbon dioxide gas was examined for a red coloring state.
As a result, the neutralization depth was zero in the specimens sprayed with aerosols 1-3A and 1-3B, but in the specimens applied with rollers of (meth) acrylic curable resins 3A and 3B, partially Neutralization up to 2.7mm was observed. This was conspicuous in the concave portion of the fracture surface.

  From Experimental Example 4, according to the method for protecting a surface of a concrete structure of the present invention, it is possible to form an organic coating evenly on an uneven surface such as a struck surface by daily inspection of the concrete structure. It can be seen that the deterioration factors of steel bars and reinforcing bars can be cut off, and excellent neutralization characteristics can be obtained.

  According to the present invention, for peeling and peeling of concrete pieces from the surface of a concrete structure, during the daily inspection, the unstable part of the joint part or the junker part or a small float is knocked down, and then When forming an organic coating to protect the surface, it can be uniformly applied over the entire surface of concrete concave and convex parts, requires no power, and does not require any materials or equipment other than aerosol. Protection is possible.

Claims (7)

  Aerosol A agent in which a (meth) acrylic resin composition containing (meth) acrylic acid ester and an organic peroxide and a mixture of a propellant are used as an aerosol, (meth) acrylic acid ester and the above A two-component (meth) acrylic comprising an aerosol B agent in which a composition obtained by mixing a (meth) acrylic resin composition containing a reducing substance capable of decomposing an organic peroxide and a propellant is used as an aerosol. A method for protecting a surface of a concrete structure, comprising spraying a curable composition on the surface of a concrete structure to obtain a cured coating of a (meth) acrylic curable resin composition on the surface of the concrete structure. The viscosity of the (meth) acrylic resin composition contained in the agent A and the agent B measured under conditions of 23 ° C. and 20 min ⁻¹ based on JIS K 7117-1: 1999 is 50 to 6,000 mPa · s. The method for protecting a surface of a concrete structure according to claim 1, wherein:   The method for protecting a surface of a concrete structure according to claim 1 or 2, wherein the propellant is dimethyl ether or liquefied natural gas.   In the spraying method, the aerosol A agent is sprayed on the concrete structure surface first, then the aerosol B agent is sprayed thereon, and the (meth) acrylic resin composition contained in the aerosol A agent and the aerosol B agent is collided and mixed. The method for protecting a surface of a concrete structure according to any one of claims 1 to 3, wherein a cured coating is obtained.   In the spraying method, the aerosol B agent is first sprayed on the surface of the concrete structure, then the aerosol A agent is sprayed thereon, and the (meth) acrylic resin composition contained in the aerosol B agent and the aerosol A agent is collided and mixed. The method for protecting a surface of a concrete structure according to any one of claims 1 to 3, wherein a cured coating is obtained.   In the spraying method, the aerosol A agent and the aerosol B agent are simultaneously sprayed on the surface of the concrete structure, and the (meth) acrylic resin composition contained in the aerosol A agent and the aerosol B agent is collided and mixed in the air to form a cured film. The method for protecting a surface of a concrete structure according to any one of claims 1 to 3, wherein:   The concrete structure surface-protected by the surface protection method of the concrete structure of any one of Claims 1-6.