JP7183580B2 - Concrete protection material - Google Patents

Description

The present invention relates to concrete protection materials.

Waterproofing materials for outdoor concrete structures require fast-curing properties that allow construction to be completed in a short period of time, as well as coating film flexibility that conforms to the base material. Such materials include urethane (meth)acrylate having a weight average molecular weight in the range of 5,000 to 200,000, (meth)acrylic monomer, and active energy ray-curable concrete containing a photopolymerization initiator. A protective material has been proposed (see, for example, Patent Document 1).

However, since this material is an ultraviolet-curing type, there is a problem that the deep-part curability of the thick film portion is insufficient.

Therefore, there has been a demand for a material that can provide a coating film that is excellent in rapid curability, flexibility, and deep curability.

JP 2018-3357 A

The problem to be solved by the present invention is to provide a concrete protective material that provides a coating film that is excellent in quick-curing properties, flexibility, and deep curing properties.

As a result of intensive research to solve the above problems, the present inventors have found that a specific urethane (meth)acrylate, a (meth)acrylic monomer (B), an organic peroxide (C), and a curing accelerator The inventors have found that by using a concrete protective material containing (D), it is possible to obtain a coating film which is excellent in rapid curing property, flexibility and deep-part curability, and completed the present invention.

That is, a concrete protective material containing urethane (meth)acrylate (A), (meth)acrylic monomer (B), organic peroxide (C), and curing accelerator (D), wherein the urethane ( Provided is an active energy ray-curable concrete protection material characterized in that the meth)acrylate (A) has a weight average molecular weight in the range of 5,000 to 50,000.

The active energy ray-curable concrete protective material of the present invention is excellent in quick-curing properties and provides a coating film with excellent flexibility and deep-curing properties. It can be suitably used during construction.

The concrete protective material of the present invention is a concrete protective material containing urethane (meth)acrylate (A), (meth)acrylic monomer (B), organic peroxide (C), and curing accelerator (D). The urethane (meth)acrylate (A) has a weight average molecular weight in the range of 5,000 to 50,000.

In the present invention, "(meth)acrylate" refers to one or both of methacrylate and acrylate, and "(meth)acrylic monomer" refers to one or both of an acrylic monomer and a methacrylic monomer. and "(meth)acrylic compound" refers to one or both of an acrylic compound and a methacrylic compound.

Examples of the urethane (meth)acrylate (A) include those obtained by reacting a polyol (a1), a polyisocyanate (a2), and a (meth)acrylic compound (a3) having a hydroxyl group or an isocyanate group. can be used.

As the polyol (a1), for example, polyether polyol, polyester polyol, polycarbonate polyol, acrylic polyol, butadiene polyol and the like can be used. These polyols may be used alone or in combination of two or more. Among these, it is preferable to use a polyether polyol from the viewpoint of improving flexibility and workability.

Examples of the polyether polyol include products obtained by addition polymerization of one or more alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide to a compound having two or more active hydrogens, and tetrahydrofuran. Polytetramethylene glycol obtained by ring-opening polymerization, modified polytetramethylene glycol obtained by copolymerizing tetrahydrofuran and alkyl-substituted tetrahydrofuran, modified polytetramethylene glycol obtained by copolymerizing neopentyl glycol and tetrahydrofuran, etc. can be used. can.

Examples of the compound having two or more active hydrogens include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1 , 2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2, 5-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl -1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-propanediol, 3 -Methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, hydroquinone, resorcinol, bisphenol A, bisphenol F, 4,4'-bisphenol, etc. Relatively low molecular weight dihydroxy compounds; 1,2-cyclobutanediol, 1,3-cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, 1,4-cyclohexanedimethanol, hydroxypropylcyclohexanol , tricyclo[5,2,1,0,2,6]decane-dimethanol, bicyclo[4,3,0]-nonanediol, dicyclohexanediol, tricyclo[5,3,1,1]dodecanediol, bicyclo [4,3,0]nonanedimethanol, tricyclo[5,3,1,1]dodecane-diethanol, hydroxypropyltricyclo[5,3,1,1]dodecanol, spiro[3,4]octanediol, butyl Alicyclic polyols such as cyclohexanediol, 1,1'-bicyclohexylidenediol, cyclohexanetriol, hydrogenated bisphenol A, and 1,3-adamantanediol; polyethers such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol Polyol; polyester polyol such as polyhexamethylene adipate, polyhexamethylene succinate, polycaprolactone, etc. can be

The number average molecular weight of the polyol (a1) is preferably in the range of 200 to 10,000, more preferably in the range of 400 to 5,000, since the flexibility and the like are further improved.

The average molecular weight in the present invention indicates a value measured by a gel permeation chromatography (GPC) method.

Examples of the polyisocyanate (a2) include aromatic diisocyanates such as xylylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate and naphthalene diisocyanate; hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, 4,4' -aliphatic such as dicyclohexylmethane diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, tetramethylxylylene diisocyanate Alternatively, a diisocyanate having an alicyclic structure can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, it is preferable to use a diisocyanate having an aliphatic or alicyclic structure because it is resistant to yellowing.

The (meth)acrylic compound (a3) having a hydroxyl group or an isocyanate group is used for the purpose of introducing a (meth)acryloyl group into the urethane (meth)acrylate (A).

(Meth)acrylic compounds having a hydroxyl group that can be used as the compound (a3) include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, (meth)acrylic acid alkyl ester having a hydroxyl group such as hydroxyethylacrylamide; trimethylolpropane di(meth) Polyfunctional (meth)acrylates having a hydroxyl group such as acrylates, pentaerythritol tri(meth)acrylate, and dipentaerythritol penta(meth)acrylate; polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, and the like can be used. Among these, acrylic acid alkyl esters having a hydroxyl group are preferably used, and 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, and hydroxyethyl acrylamide are more preferably used because of their excellent reactivity.

Examples of the (meth)acrylic compound having an isocyanate group that can be used as the compound (a3) include 2-(meth)acryloyloxyethyl isocyanate, 2-(2-(meth)acryloyloxyethyloxy)ethyl Isocyanate, 1,1-bis((meth)acryloyloxymethyl)ethyl isocyanate, and the like can be used. Among these, 2-(meth)acryloyloxyethyl isocyanate is preferably used, and 2-acryloyloxyethyl isocyanate is more preferable, because the reactivity and photocurability of the isocyanate are further improved.

As the method for producing the urethane (meth)acrylate (A) when a (meth)acrylic compound having a hydroxyl group is used as the compound (a3), for example, the polyol (a1) and the (meth)acrylic After charging the acrylic compound (a3) into the reaction system, the polyisocyanate (a2) is supplied, mixed and reacted, or a method of producing the polyol (a1) and the polyisocyanate in the absence of a solvent (a2) to obtain a urethane prepolymer having an isocyanate group, then supply the (meth)acrylic compound (a3) having a hydroxyl group, mix, and react to use a manufacturing method or the like. can be done. In any case, the reaction is preferably carried out at 20 to 120° C. for 30 minutes to 24 hours.

Further, as the method for producing urethane (meth)acrylate (A) when using a (meth)acrylic compound having an isocyanate group as the compound (a3), for example, under no solvent, the polyol (a1) and the poly An isocyanate (a2) is charged and reacted to obtain a urethane prepolymer having a hydroxyl group, and then the (meth)acrylic compound (a3) having an isocyanate group is supplied, mixed and reacted, and the like. can be used. In any case, the reaction is preferably carried out at 20 to 120° C. for 30 minutes to 24 hours.

The urethane (meth)acrylate (A) may be produced in the presence of an organic solvent.

When a (meth)acrylic compound having a hydroxyl group is used as the compound (a3), the reaction between the polyol (a1), the polyisocyanate (a2), and the (meth)acrylic compound (a3) is the polyisocyanate ( The number of equivalents of hydroxyl groups (NCO) in a2), the number of equivalents of hydroxyl groups in the polyol (a1), and the number of equivalents of hydroxyl groups in the (meth)acrylic compound (a3) ( OH) equivalent ratio [(NCO)/(OH)] is preferably in the range of 0.75 to 1 for controlling the molecular weight of the resulting urethane (meth)acrylate (A). It is more preferable to carry out in the range of 9 to 1. Further, when the equivalent ratio [(NCO)/(OH)] exceeds 1, it is preferable to use an alcohol such as methanol for the purpose of deactivating the isocyanate group of the urethane (meth)acrylate (A). .

Moreover, when manufacturing urethane (meth)acrylate (A), you may use a polymerization inhibitor, a urethanization catalyst, etc. as needed.

Examples of the polymerization inhibitor include 3,5-bistertiarybutyl-4-hydroxytoluene, hydroquinone, methylhydroquinone, hydroquinone monomethyl ether (methoquinone), 4-tertiarybutylcatechol methoxyphenol, 2,6-ditertiarybutyl Cresol, phenothiazine, tetramethylthiuram disulfide, diphenylamine, dinitrobenzene and the like can be used.

Examples of the urethanization catalyst include nitrogen-containing compounds such as triethylamine, triethylenediamine and N-methylmorpholine; metal salts such as potassium acetate, zinc stearate and tin octylate; dibutyltin laurate, zirconium tetraacetylacetonate and the like. and the like can be used.

The urethane (meth)acrylate (A) has a (meth)acryloyl group that promotes radical polymerization. The (meth)acryloyl group equivalent of the urethane (meth)acrylate (A) is preferably in the range of 3,000 to 40,000 g/eq, and 5,000 to 21, from the viewpoint of achieving both curability and flexibility. ,000 g/eq range is more preferred. The (meth)acryloyl group equivalent is the total mass of the polyol (a-1), the polyisocyanate (a-2) and the (meth)acrylic compound (a-3), and the urethane (meth)acrylate ( A) indicates a value divided by the equivalent weight of (meth)acrylic groups present in A).

The weight average molecular weight of the urethane (meth)acrylate (A) is in the range of 5,000 to 50,000. A range of 30,000 is more preferred.

Examples of the (meth)acrylic monomer (B) include isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, ) acrylate, dicyclopentenyloxyethyl (meth) acrylate and other (meth) acrylic monomers having an alicyclic structure; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate , butyl (meth)acrylate, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate ) acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, nonyl (meth)acrylate, dodecyl (meth)acrylate, 3-methylbutyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, tridecyl Aliphatic (meth) acrylic monomers such as (meth) acrylate, stearyl (meth) acrylate, neopentyl (meth) acrylate, hexadecyl (meth) acrylate, isoamyl (meth) acrylate; 3-methoxybutyl (meth) acrylate), 2-Methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-methoxybutyl (meth) acrylate, methoxypolyethylene glycol acrylate having an added mole number of oxyethylene in the range of 1 to 15, ethoxy-diethylene glycol (meth) ) acrylate, ethyl carbitol (meth) acrylate and other ether group-containing (meth) acrylic monomers; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate (Meth) acrylic monomers having a hydroxyl group such as; benzyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy polyethylene glycol acrylate, phenyl (meth) acrylate, 2-hydroxy-3-phenoxy Aromatic (meth) acrylic monomers such as propyl (meth) acrylate; (meth) acrylamide, dimethyl (meth) acrylamide, Using a (meth)acrylic monomer having a nitrogen atom such as cryloylmorpholine, dimethylaminopropyl (meth)acrylamide, isopropyl (meth)acrylamide, diethyl (meth)acrylamide, diacetone (meth)acrylamide, hydroxyethylacrylamide, etc. be able to. These (meth)acrylic monomers may be used alone or in combination of two or more.

The amount of the (meth)acrylic monomer (B) used is 30 to 30 parts per 100 parts by mass of the urethane (meth)acrylate (A), since the balance between curability and coating flexibility is further improved. It is preferably in the range of 200 parts by mass, more preferably in the range of 50 to 150 parts by mass.

Examples of the organic peroxide (C) include diacyl peroxide compounds, peroxyester compounds, hydroperoxide compounds, dialkyl peroxide compounds, ketone peroxide compounds, peroxyketal compounds, alkyl perester compounds, and percarbonates. compounds and the like can be used. More preferably, compounds are used. These compounds may be used alone or in combination of two or more.

As the diacyl peroxide compound, for example, benzoyl peroxide, toluyl peroxide, acetyl peroxide, lauroyl peroxide and the like can be used. Among these, benzoyl peroxide is preferably used. These compounds may be used alone or in combination of two or more.

Examples of the hydroperoxide compound include cumene hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, tetramethylbutyl hydroperoxide, t-hexyl hydroperoxide, and t-butyl hydroperoxide. Among these, cumene hydroperoxide and diisopropylbenzene hydroperoxide are preferably used, and cumene hydroperoxide is more preferably used, because of their superiority in coating film curability. These compounds may be used alone or in combination of two or more.

Examples of the ketone peroxide compound include acetylacetone peroxide, methyl ethyl ketone peroxide, diethyl ketone peroxide, methyl propyl ketone peroxide, methyl isobutyl peroxide, methyl acetoacetate peroxide, ethyl acetate peroxide, cyclohexanone peroxide, methyl Cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide and the like can be used, but among these, methyl ethyl ketone peroxide and acetylacetone peroxide are preferably used because of their superiority in coating film curing. More preferably, methyl ethyl ketone peroxide is used. These compounds may be used alone or in combination of two or more.

The amount of the organic peroxide (C) used is 0.01 part per 100 parts by mass in total of the urethane (meth)acrylate (A) and the acrylic monomer (B) in terms of room temperature curing. It is preferably in the range of up to 10 parts by mass, more preferably in the range of 0.1 to 5 parts by mass.

The curing accelerator (D) is preferably a substance that decomposes the organic peroxide of the curing agent (C) by a redox reaction to facilitate the generation of active radicals. , cobalt salts of organic acids such as cobalt octylate; organic acid salts such as zinc octylate, vanadium octylate, copper naphthenate and barium naphthenate; metal chelate compounds such as vanadium acetylacetate, cobalt acetylacetate and iron acetylacetonate ; aniline, N,N-dimethylaniline, N,N-diethylaniline, 4-(N,N-dimethylamino)benzaldehyde, 4-[N,N-bis(2-hydroxyethyl)amino]benzaldehyde, 4-( N-methyl-N-hydroxyethylamino)benzaldehyde, N-ethyl-m-toluidine, triethanolamine, m-toluidine, diethylenetriamine, pyridine, phenylmorpholine, piperidine, N,N-bis(hydroxyethyl)aniline, diethanol N,N-substituted anilines such as aniline, N,N-substituted-p-toluidine, 4-(N,N-substituted amino)benzaldehyde, p-toluidine, N,N-dimethyl-p-toluidine, N,N- Ethylene oxide adduct of dimethyl-p-toluidine, N,N-bis(2-hydroxyethyl)-p-toluidine, N,N-bis(2-hydroxypropyl)-p-toluidine, N-ethyl-m-toluidine An amine compound such as can be used. These compounds may be used alone or in combination of two or more. Cobalt salts of organic acids and amine compounds are preferably used, and more preferably used in combination, because they are superior in coating film curability. Preferred organic acid cobalt salts are cobalt naphthenate and cobalt octylate, and preferred amine compounds are toluidine compounds.

The amount of the curing accelerator (D) used is 0.00 parts per 100 parts by mass in total of the radically polymerizable resin (A) and the radically polymerizable monomer (B) from the standpoint of room temperature curing. 001 to 5 parts by mass, more preferably 0.01 to 3 parts by mass.

The concrete protective material of the present invention contains the urethane (meth)acrylate (A), the (meth)acrylic monomer (B), the organic peroxide (C), and the curing accelerator (D). However, other additives and the like may be contained as necessary.

Examples of the other additives include petroleum wax, pigments, thixotropic agents, antioxidants, solvents, fillers, reinforcing agents, flame retardants, and the like. These additives may be used alone or in combination of two or more. Among these, petroleum wax is preferably used in order to obtain excellent surface drying properties of the concrete protective material.

The petroleum wax segregates on the surface of the coating film of the radically polymerizable resin composition and prevents inhibition of curing of radical polymerization by oxygen. For example, paraffin wax, microcrystalline wax, petrolactam, etc. can be used. . These petroleum waxes may be used alone or in combination of two or more. The melting point of the petroleum wax is preferably in the range of 42 to 73°C, more preferably in the range of 46 to 66°C. The melting point of the petroleum wax is a value measured according to JISK2235:2009.

The protective material for concrete of the present invention can be suitably used as a protective material for concrete such as cement concrete, asphalt concrete, mortar concrete, resin concrete, permeable concrete, and ALC (Autoclaved Lightweight Aerated Concrete) plates.

The concrete protective material of the present invention has a sufficient pot life, is excellent in rapid curing, and provides a coating film excellent in flexibility and deep curing. can be suitably used during construction.

The present invention will be described in more detail below with specific examples. The average molecular weight is measured under the following GPC measurement conditions.

[GPC measurement conditions]
Measuring device: high-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8mm I.D. x 30cm) x 1 "TSKgel G4000" (7.8mm I.D. x 30cm) x 1 "TSKgel G3000" (7.8mm I.D. x 30cm) x 1 Book "TSKgel G2000" (7.8 mm I.D. x 30 cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40°C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 4 mg/mL)
Standard sample: A calibration curve was created using the following monodisperse polystyrene.

(monodispersed polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

(Synthesis Example 1: Synthesis of urethane (meth)acrylate (A-1))
288.1 parts by mass of polytetramethylene glycol having a number average molecular weight of 1,000 (hereinafter abbreviated as "PTMG1000"), 2-hydroxy 4.2 parts by mass of ethyl acrylate (hereinafter abbreviated as “HEA”), 1.7 parts by mass of 2,6-di-tert-butyl-cresol, and 0.3 parts by mass of p-methoxyphenol were added. After raising the temperature in the reaction vessel to 40° C., 106.5 parts by mass of isophorone diisocyanate (hereinafter abbreviated as “IPDI”) was added. Therefore, 0.06 parts by mass of dioctyltin dineodecanate was added, and the temperature was raised to 80° C. over 1 hour. After that, hold at 80 ° C. for 12 hours, cool after confirming that all isocyanate groups have disappeared, and urethane (meth) acrylate (A- 1) was obtained.

(Synthesis Example 2: Synthesis of urethane (meth)acrylate (A-2))
465.9 parts by mass of PTMG1000, 9.6 parts by mass of HEA, and 1.7 parts by mass of 2,6-di-tert-butyl-cresol were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer. , and 0.3 parts by mass of p-methoxyphenol were added. After raising the temperature in the reaction vessel to 40° C., 101.5 parts by mass of IPDI was added. Therefore, 0.06 parts by mass of dioctyltin dineodecanate was added, and the temperature was raised to 80° C. over 1 hour. After that, hold at 80 ° C. for 12 hours, cool after confirming that all isocyanate groups have disappeared, and urethane (meth) acrylate (A- 2) was obtained.

(Synthesis Example 3: Synthesis of urethane (meth)acrylate (A-3))
85.5 parts by mass of polyoxypropylene glycol having a number average molecular weight of 3,000 (hereinafter abbreviated as "PPG3000") and PTMG1000 400 were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer. .2 parts by mass, 103.0 parts by mass of polyethylene glycol having a number average molecular weight of 400 (hereinafter abbreviated as "PEG400"), 8.5 parts by mass of HEA, and 2,6-di-tert-butyl-cresol. 5 parts by mass and 0.2 parts by mass of p-methoxyphenol were added. After the temperature inside the reaction vessel was raised to 40° C., 98.8 parts by mass of IPDI was added. Therefore, 0.01 part by mass of dioctyltin dineodecanate was added, and the temperature was raised to 80° C. over 1 hour. After that, hold at 80 ° C. for 12 hours, cool after confirming that all isocyanate groups have disappeared, and urethane (meth) acrylate (A- 3) was obtained.

(Synthesis Example 4: Synthesis of urethane (meth)acrylate (A-4))
288.1 parts by mass of PTMG1000, 5.0 parts by mass of HEA, and 1.7 parts by mass of 2,6-di-tert-butyl-cresol were placed in a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, and a thermometer. , and 0.3 parts by mass of p-methoxyphenol were added. After raising the temperature in the reaction vessel to 40° C., 106.5 parts by mass of IPDI was added. Therefore, 0.06 parts by mass of dioctyltin dineodecanate was added, and the temperature was raised to 80° C. over 1 hour. After that, hold at 80 ° C. for 12 hours, cool after confirming that all isocyanate groups have disappeared, and urethane (meth) acrylate (A- 4) was obtained.

(Synthesis Example 5: Synthesis of urethane (meth)acrylate (RA-1))
A four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, an air inlet and a reflux condenser was charged with 500 parts by mass of PTMG1000 and 172 parts by mass of tolylene diisocyanate (hereinafter abbreviated as "TDI"), The reaction was carried out at 80° C. for 2 hours under a nitrogen stream. Since the NCO equivalent became 600, which is almost the theoretical equivalent value, it was cooled to 50°C. Under an air stream, 0.07 parts by mass of hydroquinone was added, 65 parts by mass of 2-hydroxyethyl methacrylate (hereinafter abbreviated as "HEMA") was added, and the mixture was reacted at 90°C for 4 hours. When the NCO% became 0.1% or less, 0.07 parts by mass of 4-tertiarybutylcatechol (hereinafter abbreviated as "TBC") was added, and a urethane (meth) with a weight average molecular weight of 1,500 was added. Acrylate (RA-1) was obtained.

(Synthesis Example 6: Synthesis of urethane (meth)acrylate (RA-2))
A four-necked flask equipped with a thermometer, a stirrer, an inert gas inlet, an air inlet and a reflux condenser was charged with 500 masses of polytetramethylene glycol having a number average molecular weight of 2,000 (hereinafter abbreviated as "PTMG2000"). parts and 87 parts by mass of TDI were charged and reacted at 80° C. for 2 hours under a nitrogen stream. Since the NCO equivalent became 600, which is almost the theoretical equivalent value, it was cooled to 50°C. 0.07 parts by mass of hydroquinone and 65 parts by mass of HEMA were added under an air stream, and the mixture was reacted at 90° C. for 4 hours. When the NCO% became 0.1% or less, 0.07 parts by mass of TBC was added to obtain urethane (meth)acrylate (RA-2) having a weight average molecular weight of 2,500.

(Example 1: Preparation and evaluation of concrete protective material (1))
100 parts by mass of urethane (meth)acrylate (A-1) obtained in Synthesis Example 1, 60 parts by mass of normal octyl acrylate (hereinafter abbreviated as "nOA"), acryloylmorpholine (hereinafter abbreviated as "ACMO". ) 40 parts by weight, p-toluidine ethylene oxide 2 mol adduct (hereinafter abbreviated as "PTD-2EO") 0.4 parts by weight, cobalt octylate 0.5 parts by weight, 130 ° F paraffin wax 0.4 parts Mixture (1) was obtained by mixing 4 parts by mass and stirring until uniform.
To 100 parts by mass of this mixture (1), 2 parts by mass of "Niper NS" (40% benzoyl peroxide) manufactured by NOF Corporation was added to prepare a concrete protection material (1).

[Curability evaluation]
In an environment of 23° C., the concrete protective material (1) obtained above was applied to the surface of a 50 μm-thick polyethylene terephthalate film (hereinafter abbreviated as “release PET50”) whose surface was subjected to release treatment. It was applied so that the film thickness was 500 μm, the time until the coating film was cured was measured, and the curability was evaluated according to the following criteria. The surface of the coating film was touched with a finger, and the absence of adhesion of the resin was determined as curing.
○: Less than 60 minutes ×: 60 minutes or more

[Evaluation of Deep Curability]
In an environment of 23° C., the concrete protective material (1) obtained above was applied to the surface of the release PET 50 so as to have a film thickness of 3 mm. After 60 minutes, the release film was peeled off, and the lower surface of the coating film was touched with a finger to evaluate deep-part curability according to the following criteria.
○: Resin does not adhere to fingers ×: Resin adheres to fingers

[Evaluation of coating film flexibility]
The 3 mm thick coating film obtained above was subjected to a tensile test according to JIS K 6911, and the flexibility of the coating film was evaluated according to the following criteria.
○: Elongation is 1,000% or more ×: Elongation is less than 1,000%

(Examples 2 to 4: Preparation and evaluation of concrete protective materials (2) to (4))
Concrete protective material in the same manner as in Example 1, except that the urethane (meth)acrylate (A-1) used in Example 1 was changed to urethane (meth)acrylates (A-2) to (A-4). After preparing (2) to (4), each physical property was evaluated.

(Example 5: Preparation and evaluation of concrete protection material (5))
After preparing concrete protective material (5) in the same manner as in Example 1, except that the amount of PTD-2EO used in Example 1 was changed from 0.4 parts by mass to 0.6 parts by mass, each physical property was measured. evaluated.

(Example 6: Preparation and evaluation of concrete protection material (6))
Concrete protection material (6) was prepared in the same manner as in Example 1, except that 60 parts by mass of nOA used in Example 1 was changed to 60 parts by mass of normal butyl acrylate (hereinafter abbreviated as "nBA"). After that, each physical property was evaluated.

(Comparative Example 1: Preparation and Evaluation of Concrete Protective Material (R1))
100 parts by mass of urethane (meth)acrylate (A-1), 60 parts by mass of nOA, 40 parts by mass of ACMO, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide (hereinafter abbreviated as "TPO")1. A concrete protection material (R1) was prepared by mixing 4 parts by mass and stirring until uniform.

[Curability evaluation (UV irradiation)]
In an environment of 23° C., the concrete protective material (R1) was applied to the surface of the release PET50 so that the film thickness after UV irradiation would be 500 μm. After that, UV irradiation is performed with a UV irradiation device so that the integrated light amount of the wavelength in the UV-A region is 10 kJ / m ² , and then the time until the coating film is cured is measured, and the curability is evaluated according to the following criteria. evaluated. The surface of the coating film was touched with a finger, and the absence of adhesion of the resin was determined as curing.
○: Less than 60 minutes ×: 60 minutes or more

[Evaluation of deep part curability (UV irradiation)]
In an environment of 23° C., the concrete protective material (R1) was applied to the surface of the release PET50 so that the film thickness after UV irradiation would be 3 mm. After that, UV irradiation was performed using a UV irradiation device so that the integrated amount of light with a wavelength in the UV-A region was 10 kJ/m ² . The bottom surface of the coating film was touched with a finger to evaluate deep-part curability according to the following criteria.
○: Resin does not adhere to fingers ×: Resin adheres to fingers

[Evaluation of coating film flexibility (UV irradiation)]
The 3 mm thick coating film obtained above was subjected to a tensile test according to JIS K 6911 to measure the tensile elongation.

(Comparative Example 2: Preparation and evaluation of concrete protection material (R2))
After preparing the concrete protective material (R2), each physical property was evaluated in the same manner as in Comparative Example 1, except that the amount of TPO used in Comparative Example 1 was changed from 1.4 parts by mass to 0.5 parts by mass. .

(Comparative Examples 3 to 6: Preparation and evaluation of concrete protective materials (R3) to (R6))
After preparing the concrete protective materials (R3) to (R6) in the same manner as in Example 1, except that the urethane (meth)acrylate (A-1) used in Example 1 was changed as shown in Table 2, each Physical properties were evaluated.

Tables 1 and 2 show the compositions and evaluation results of concrete protective materials (1) to (6) and concrete protective materials (R1) to (R6) obtained above.

It was confirmed that the concrete protective materials of the present invention of Examples 1 to 6 are excellent in fast curing property and deep curing property, and that coating films having excellent coating film flexibility can be obtained.

Comparative Examples 1 and 2 are examples of UV-curable concrete protective materials, but it was confirmed that deep-part curability was insufficient.

Comparative Examples 3 and 4 are examples in which a urethane (meth)acrylate having a weight average molecular weight lower than 5,000, which is the lower limit of the present invention, was used. One thing has been confirmed.

Claims (3)

A concrete protective material containing a urethane (meth)acrylate (A), a (meth)acrylic monomer (B), an organic peroxide (C), and a curing accelerator (D), wherein the (meth)acrylic Monomer (B) is methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, sec-butyl (meth) acrylate, isobutyl (meth) Acrylate, 2-ethylbutyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, n-octyl (meth)acrylate, nonyl ( meth)acrylate, dodecyl (meth)acrylate, 3-methylbutyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, neopentyl (meth)acrylate, hexadecyl ( meth) acrylate, and one or more aliphatic (meth) acrylic monomers selected from the group consisting of isoamyl (meth) acrylate, (meth) acrylamide, dimethyl (meth) acrylamide, acryloylmorpholine, dimethylaminopropyl (meth) and a (meth)acrylic monomer having one or more nitrogen atoms selected from the group consisting of acrylamide, isopropyl (meth)acrylamide, diethyl (meth)acrylamide, diacetone (meth)acrylamide, and hydroxyethylacrylamide. Yes, the amount of the (meth)acrylic monomer (B) used is in the range of 50 to 150 parts by mass with respect to 100 parts by mass of the urethane (meth)acrylate (A), and the organic peroxide ( The amount of C) used is in the range of 0.01 to 10 parts by mass with respect to a total of 100 parts by mass of the urethane (meth)acrylate (A) and the (meth) acrylic monomer (B), The amount of the curing accelerator (D) used is 0.001 to 5 parts by mass with respect to a total of 100 parts by mass of the urethane (meth)acrylate (A) and the (meth)acrylic monomer (B). range, and the urethane (meth)acrylate (A) is obtained by reacting a polyether polyol, a polyisocyanate (a2), and a (meth)acrylic compound (a3) having a hydroxyl group or an isocyanate group. and wherein the urethane (meth)acrylate (A) has a weight average molecular weight in the range of 5,000 to 50,000.
The concrete protection material according to claim 1, wherein the urethane (meth)acrylate (A) has a (meth)acryloyl group equivalent in the range of 3,000 to 40,000. 3. The concrete protection material according to claim 1, wherein said hardening accelerator (D) is a cobalt salt of an organic acid and/or an amine compound.