JP7706980B2 - Epoxy resin composition - Google Patents

Description

The present invention relates to an epoxy resin composition.

Epoxy resins are used in a wide range of applications, including civil engineering, casting materials, and adhesives, due to their excellent chemical and physical properties.
For example, in the civil engineering and construction field, it is used as an adhesive for post-installed anchors, and is used when drilling holes in concrete structures to fix anchor bolts, etc. Since it is applied on-site, there are cases where the adhesive is used in a state where the adhesive surface is wet due to rainfall, etc. However, when water is present at the interface between the epoxy resin and the adherend, the wetting of the epoxy resin to the adherend surface is hindered, and there is a problem that the adhesive strength is significantly reduced.
Known techniques for improving adhesion to wet surfaces include a method of improving adhesion to water-wet surfaces by blending cement with an epoxy resin mixture consisting of a liquid epoxy resin and an amine hardener (Patent Document 1), a method of adding an aromatic alcohol to an epoxy resin, an epoxy hardener, and an inorganic filler (Patent Document 2), and a method of adding a silane coupling agent (Patent Document 3).
However, the method of adding cement or aromatic alcohol has a problem of insufficient adhesive strength with the adherend, and the method of adding a silane coupling agent has a problem of insufficient adhesive strength if a gap occurs between the adhesive and the adherend due to shrinkage during curing.

Japanese Unexamined Patent Publication No. 57-12024 JP 2002-338662 A JP 2014-19631 A

The present invention aims to provide an epoxy resin composition that can suppress volumetric shrinkage during curing, and can provide a cured product that has excellent adhesion to wet surfaces and excellent mechanical strength.

As a result of investigations aimed at achieving the above object, the present inventors arrived at the present invention.
That is, the present invention relates to an epoxy resin composition containing a polyepoxide (A), a polyamine (B) having 2 to 50 active hydrogen atoms directly bonded to N atoms, an expanding agent (C), water (D) and a silane coupling agent (E), wherein the expanding agent (C) contains calcium oxide, the silane coupling agent (E) is a compound having at least one alkoxy group bonded to a silicon atom and at least one functional group selected from the group consisting of an amino group, a mercapto group and an epoxy group, and the molar ratio (CaO/alkoxy group) of calcium oxide in the expanding agent (C) to the alkoxy group bonded to a silicon atom in the silane coupling agent (E) is 1 to 40; and a cured product obtained by curing the epoxy resin composition.

The epoxy resin composition of the present invention has the following effects.
(1) The composition exhibits extremely little volumetric shrinkage during curing or moderate expansion during curing, and is therefore excellent in suppressing volumetric shrinkage, which can be evaluated by the volume change (%) before and after curing, as described below.
(2) Excellent adhesion to wet surfaces.
(3) The deterioration of physical properties caused by the incorporation of silane coupling agents is minimal, and a cured product having excellent mechanical strength is obtained.

The epoxy resin composition of the present invention is an epoxy resin composition containing a polyepoxide (A), a polyamine (B) having 2 to 50 active hydrogen atoms directly bonded to N atoms, an expanding agent (C), water (D) and a silane coupling agent (E), in which the expanding agent (C) contains calcium oxide, the silane coupling agent (E) is a compound having at least one alkoxy group bonded to a silicon atom and at least one functional group selected from the group consisting of an amino group, a mercapto group and an epoxy group, and the molar ratio (CaO/alkoxy group) of calcium oxide in the expanding agent (C) to the alkoxy group bonded to a silicon atom in the silane coupling agent (E) is 1 to 40.

[Polyepoxide (A)]
The polyepoxide (A) in the present invention has two or more epoxy groups in the molecule and has no alkoxy groups bonded to silicon atoms. From the viewpoints of the physical properties (mechanical strength, etc.) of the cured product and the handleability of the epoxy resin composition, the number of epoxy groups is preferably 2 to 10, more preferably 2 to 6.
The polyepoxide (A) may be used alone or in combination of two or more kinds.

The number average molecular weight of (A) [hereinafter abbreviated as Mn. Measurement is performed by gel permeation chromatography (GPC) under conditions described below] is preferably 100 to 10,000, more preferably 160 to 3,000, from the viewpoints of the physical properties (mechanical strength, etc.) of the cured product and the handleability of the epoxy resin composition.
The epoxy equivalent of (A) (the molecular weight per epoxy group) is preferably 50 to 1,000, and more preferably 80 to 500, from the viewpoints of the physical properties (mechanical strength, etc.) of the cured product and the handleability of the epoxy resin composition.

(A) includes the following (A1) to (A4), and mixtures of two or more of these.

(A1) Polyglycidyl Ethers (A11) Diglycidyl Ethers of Dihydric Phenols [having 6 to 30 Carbon Atoms (hereinafter abbreviated as C)] Diglycidyl ethers of bisphenols (such as bisphenol-F, -A, -B, -AD or S), diglycidyl ethers of halogenated bisphenol A (such as tetrachlorobisphenol A), diglycidyl ethers of monocyclic dihydric phenols (catechol, resorcinol, hydroquinone, etc.), diglycidyl ethers of condensed polycyclic dihydric phenols (1,5-dihydroxynaphthalene, dihydroxybiphenyl, octachloro-4,4'-dihydroxybiphenyl, 9,9'-bis(4-hydroxyphenyl)fluorene, etc.), diglycidyl ethers obtained by reacting 2 moles of bisphenol A with 3 moles of epichlorohydrin, etc.;

(A12) Polyglycidyl ethers of polyhydric (trihydric to hexahydric or higher) phenols Polyglycidyl ethers of polyhydric phenols (C6 or higher and Mn 5,000 or lower), such as triglycidyl ether of trihydric phenols (pyrogallol, dihydroxynaphthyl cresol, tris(hydroxyphenyl)methane, dinaphthyltriol, p-glycidylphenyldimethyltriyl bisphenol A, etc.), tetraglycidyl ether of tetrahydric phenols (tetrakis(4-hydroxyphenyl)ethane, 4,4'-oxybis(1,4-phenylethyl)tetracresol, bis(dihydroxynaphthalene), etc.), polyglycidyl ethers of terephthalic acid, phenol or cresol novolac resins (Mn 400 to 5,000), polyglycidyl ethers of limonene phenol novolac resins (Mn 400 to 5,000), polyglycidyl ethers of polyphenols (Mn 400 to 5,000) obtained by the condensation reaction of phenol with glyoxal, glutaraldehyde or formaldehyde, and polyglycidyl ethers of polyphenols (Mn 400 to 5,000) obtained by the condensation reaction of resorcinol with acetone;

(A13) Diglycidyl ethers of aliphatic diols (C2 or more and Mn 5,000 or less) Diglycidyl ethers of aliphatic diols [dihydric alcohols [e.g., ethylene glycol, propylene glycol, tetramethylene glycol, neopentyl glycol, 1,6-hexanediol (hereinafter abbreviated as EG, PG, TMG, NPG, and 1,6-HD, respectively), polyalkylene glycols [e.g., polyethylene glycol (hereinafter abbreviated as PEG, molecular weight 106 or more and Mn 4,000 or less), polypropylene glycol (hereinafter abbreviated as PPG, molecular weight 134 or more and Mn 5,000 or less), polytetramethylene glycol (hereinafter abbreviated as PTMG, molecular weight 162 or more and Mn 5,000 or less)], etc.];

(A14) Polyglycidyl ethers of aliphatic poly(tri- to hexahydric or higher)ols (C6 or higher and Mn 10,000 or lower) Polyglycidyl ethers of aliphatic polyols (polyhydric (tri- to hexahydric) alcohols [trimethylolpropane, glycerin, pentaerythritol, sorbitol (hereinafter abbreviated as TMP, GR, PE, SO, etc.)], intramolecular or intermolecular dehydration products of polyhydric alcohols [poly(n=2-5)GR], and alkylene oxide [hereinafter abbreviated as AO, C2-6, for example, ethylene oxide, 1,2-propylene oxide (hereinafter abbreviated as EO, PO, etc.)] adducts of these polyhydric alcohols, etc.);

(A15) Polyglycidyl ethers of alicyclic ring-containing poly(dihydric to tetrahydric or higher)ols Those having C3 or more and Mn of 5,000 or less, for example, polyglycidyl ethers of 1,2-cyclopropanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 1,4-cyclohexanediol, hydrogenated bisphenol A, 1,2,3-cyclopropanetriol, 1,3,5-cyclohexanetriol, sucrose, and AO (1 to 20 mol) adducts thereof;

(A16) Polyglycidyl ethers of aromatic ring-containing polyhydric (dihydric to tetrahydric or higher) alcohols, such as polyglycidyl ethers having C8 or more and Mn of 5,000 or less, AO (1 to 20 mol) adducts of bisphenol A, m- or p-xylylene glycol, benzenediethanol, 1,2-diphenylethane-1,2-diol, 1,1,2,2,-tetraphenylethane-1,2-diol, and AO (1 to 20 mol) adducts thereof;

(A2) Polyglycidyl esters (A21) Glycidyl esters of aromatic polyvalent (divalent to hexavalent or higher) carboxylic acids Polyglycidyl esters of aromatic polyvalent carboxylic acids (C6 to C20 or higher), such as diglycidyl esters of aromatic dicarboxylic acids (such as ortho-, iso-, or terephthalic acid), triglycidyl esters of aromatic tricarboxylic acids (such as trimellitic acid);
(A22) Polyglycidyl esters of aliphatic or alicyclic polycarboxylic acids (C6 to C20 or more), such as diglycidyl esters of aliphatic dicarboxylic acids (oxalic acid, maleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, etc.), triglycidyl esters of aliphatic tricarboxylic acids (tricarballylic acid, etc.), (co)polymers of glycidyl (meth)acrylate (degree of polymerization: 2 to 10), polyglycidyl esters of alicyclic polycarboxylic acids (dimer acid, etc.), and nuclear hydrogenated products of the above (A21);

(A3) Glycidyl amines of polyamines (C6 to C20 or more and having 2 to 10 or more active hydrogen atoms directly bonded to nitrogen atoms) (A31) Polyglycidyl amines of aromatic amines, such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, N,N,N',N'-tetraglycidyldiaminodiphenylmethane, N,N,N',N'-tetraglycidyldiaminodiphenylsulfone, N,N,N',N'-tetraglycidyldiaminoethylphenylmethane, and N,N,O-triglycidylaminophenol;
(A32) Polyglycidyl amines of aliphatic amines, for example, N,N,N',N'-tetraglycidylxylylenediamine, N,N,N',N'-tetraglycidylhexamethylenediamine;
(A33) Polyglycidyl amines of alicyclic or heterocyclic amines (C6 to C20 or more and having 2 to 10 or more active hydrogens directly bonded to nitrogen atoms) Polyglycidyl amines of alicyclic amines (e.g., hydrogenated N,N,N',N'-tetraglycidylxylylenediamine), polyglycidyl amines of heterocyclic amines (e.g., trisglycidylmelamine);

(A4) Other polyepoxides (A41) Aliphatic poly(2-6 or more)epoxides having C6 or more and Mn of 2,500 or less, such as epoxidized polybutadiene and epoxidized soybean oil;
(A42) Alicyclic poly(dihydric to tetrahydric or higher) epoxides Those having a C of 6 or more and a Mn of 2,500 or less, such as vinylcyclohexene dioxide, limonene dioxide, dicyclopentadiene dioxide, bis(2,3-epoxycyclopentyl)ether, ethylene glycol bisepoxydicyclopentyl ether, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexanecarboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, and bis(3,4-epoxy-6-methylcyclohexylmethyl)butylamine.

Of these (A), from the viewpoint of the physical properties (mechanical strength, etc.) of the cured product, preferred are (A1) and (A2), more preferred are (A11) and (A12), and particularly preferred are glycidyl ether of bisphenol F, diglycidyl ether of bisphenol A, polyglycidyl ether of phenol novolac resin, and polyglycidyl ether of cresol novolac resin.

[Polyamine (B)]
The polyamine (B) in the present invention has 2 to 50, preferably 2 to 10, and more preferably 3 to 8 active hydrogen atoms directly bonded to N atoms. If the number is less than 2, the physical properties (mechanical strength, etc.) of the cured product will be poor, and if the number exceeds 50, the handleability of the epoxy resin composition will be poor.
The polyamine (B) may be used alone or in combination of two or more kinds.

The Mn of (B) is preferably 30 to 25,000, more preferably 45 to 1,600, from the viewpoints of the physical properties (mechanical strength, etc.) of the cured product and the handleability of the epoxy resin composition.

The active hydrogen equivalent of (B) (the molecular weight per active hydrogen) is preferably 15 to 500, more preferably 20 to 200, from the viewpoint of the physical properties (mechanical strength, etc.) of the cured product and from the viewpoint of industrial applications.

(B) includes the following (B1) to (B9), and mixtures of two or more of these.

(B1) Aliphatic poly(di-hepta)amines having C2 or more and Mn of 500 or less, such as C2-10 alkylenediamines (ethylenediamine, propylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.), polyalkylene (C2-10) poly(tri- to hexavalent or higher)amines [diethylenetriamine, iminobispropylamine, bis(hexamethylene)triamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, etc.], as well as their alkyl (C1-4) or hydroxyalkyl (C2-4) substituted derivatives, such as dialkyl (C1-3) aminopropylamine, trimethylhexamethylenediamine, aminoethylethanolamine, 2,5-dimethyl-2,5-hexamethylenediamine, methyliminobispropylamine, N,N'-di-n-butyl-1,6-hexanediamine;

(B2) Alicyclic ring-containing poly(di- to trivalent)amines having C4 to C15, for example, 1,3-diaminocyclohexane, 1,3-bisaminomethylcyclohexane, isophoronediamine, menthenediamine, 4,4'-methylenedicyclohexanediamine (hydrogenated methylenedianiline);

(B3) Heterocycle-containing poly(di- to tri-valent)amines having C4 to C15, for example, piperazine, N-aminoethylpiperazine, 1,4-diaminoethylpiperazine, 1,4-bis(2-amino-2-methylpropyl)piperazine;

(B4) Aromatic ring-containing polyamines having C8 to C15, such as xylylenediamine, tetrachloro-p-xylylenediamine;

(B5) Polyamide polyamines: those having a molecular weight of 200 or more and Mn of 1,000 or less, such as polyamide polyamines obtained by condensation of a dicarboxylic acid (dimer acid, etc.) with an excess of [2 or more equivalents of the above (B1) or the like per equivalent of carboxyl group];

(B6) Polyether polyamines Those having a molecular weight of 100 or more and an Mn of 1,000 or less, such as hydrogenated products of cyanoethylated polyether polyols [such as the above-mentioned polyalkylene glycols];

(B7) Epoxy-added polyamines: those with a molecular weight of 100 or more and Mn of 1,000 or less, such as a reaction product of 1 mole of an epoxy compound with 1 to 30 moles of the above (B1) [a reaction product of 1 mole of an epoxy compound [the above polyepoxide (A) and monoepoxide (butyl glycidyl ether, phenyl glycidyl ether, etc.)] with 1 to 30 moles of the above aliphatic polyamine (B1) (molecular weight of 100 or more and Mn of 1,000 or less), etc.];

(B8) Cyanoethylated polyamines having a molecular weight of 100 or more and Mn of 500 or less, such as a mixture of acrylonitrile and the above (B1)
(e.g., biscyanoethyldiethylenetriamine);

(B9) Other polyamines (B91) Hydrazine compounds (those with a molecular weight of 32 or more and Mn of 500 or less, such as hydrazine and monoalkylhydrazine)
(B92) Dihydrazide compounds [those with a molecular weight of 74 or more and Mn of 1,000 or less, such as acid (succinic acid, adipic acid, isophthalic acid, terephthalic acid, etc.) dihydrazides]
(B93) Guanidine compounds (those having a molecular weight of 59 or more and Mn of 500 or less, such as butylguanidine and 1-cyanoguanidine).

Of the above (B), from the viewpoint of the physical properties (mechanical strength, etc.) of the cured product, preferred are (B1) to (B5), more preferred are (B1), (B4) and (B5), and particularly preferred are (B1) and (B4).

[Expansion agent (C)]
The expanding agent (C) in the present invention expands upon reaction with water and contains calcium oxide.

The shape of (C) is preferably a powder from the viewpoint of handling properties of the epoxy resin composition.
The volume average particle size of (C) is preferably 0.1 to 800 μm, and more preferably 0.5 to 250 μm, from the viewpoints of the viscosity and workability of the epoxy resin composition.

Examples of (C) that are commercially available include products under the trade names "Taiheiyo Hyper Expan (for structural use)", "Taiheiyo Hyper Expan M (for structural use, hydration heat suppression type)", "Taiheiyo Expan (for structural use)", and "Taiheiyo Expan (for product use)", all manufactured by Taiheiyo Materials Co., Ltd., and products under the trade names "Denka Power CSA Type S", "Denka Power CSA Type R", "Denka Power CSA Type T", "Denka CSA #10", and "Denka CSA #20", all manufactured by Denki Kagaku Kogyo Co., Ltd.

[Water (D)]
Examples of the water (D) in the present invention include ion-exchanged water, ultrapure water, distilled water, tap water, city water, industrial water, and a mixture of two or more of these. From the viewpoint of the physical properties (mechanical strength, etc.) of the cured product and industrial viewpoints, ion-exchanged water, ultrapure water, and distilled water are preferred, and ion-exchanged water is more preferred.

[Silane coupling agent (E)]
The silane coupling agent (E) in the present invention is a compound having at least one alkoxy group bonded to a silicon atom and at least one functional group selected from the group consisting of an amino group, a mercapto group, and an epoxy group.
The silane coupling agent (E) has at least one functional group selected from the group consisting of an amino group, a mercapto group, and an epoxy group, and is therefore capable of reacting with (A) or (B) in the epoxy resin composition, thereby imparting adhesion to a wet surface of the epoxy resin composition.
In addition, the alkoxy group bonded to silicon in the silane coupling agent (E) is hydrolyzed by the water (D) in the epoxy resin composition or the water attached to the adhesive surface in a wet state to generate an alcohol. This alcohol acts as a plasticizer in the cured product of the epoxy resin composition, which has the problem of reducing the mechanical strength, but in the present invention, it is presumed that by including calcium oxide as the expanding agent (C), the generated alcohol reacts with calcium oxide to obtain an epoxy resin composition that can obtain a cured product with excellent adhesion to wet surfaces without impairing the mechanical strength.

Examples of the silane coupling agent (E) include those having an amino group {aminoalkyl (preferably having 2 to 10 carbon atoms) trialkoxy (preferably having an alkoxy group with 1 to 10 carbon atoms) silanes (specifically, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, etc.), N-substituted aminoalkyl (preferably having 2 to 10 carbon atoms) trialkoxy (preferably having an alkoxy group with 1 to 10 carbon atoms) silanes (specifically, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, etc.), dimethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-(methylamino)propyltrimethoxysilane, 3-(methylamino)propyltriethoxysilane, etc.)}, those having a mercapto group {mercaptoalkyl (preferably having 2 to 10 carbon atoms) trialkoxy (preferably having 1 to 10 carbon atoms in the alkoxy group) silane (specifically, 3-mercapto silanes having an epoxy group {glycidoxyalkyl (preferably having 2 to 10 carbon atoms) trialkoxy (preferably having 1 to 10 carbon atoms in the alkoxy group) silanes (specifically, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltriethoxysilane, etc.), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 5,6-epoxyhexyltrimethoxysilane, 5,6-epoxyhexylmethyldimethoxysilane, 5,6-epoxyhexylmethyldiethoxysilane, 5,6-epoxyhexyltriethoxysilane, and the like}.
Among these, from the viewpoints of reactivity with the expanding agent (C) and adhesiveness, the alkoxy group preferably has 1 to 5 carbon atoms, and more preferably has 1 to 3 carbon atoms.
From the viewpoint of the volume change rate, those having an amino group are preferred.

[Epoxy resin composition]
The epoxy resin composition of the present invention contains the above-mentioned (A), (B), (C), (D) and (E), and the molar ratio (CaO/alkoxy group) of calcium oxide in the expanding agent (C) to the alkoxy group bonded to a silicon atom in the silane coupling agent (E) is 1 to 40. If the molar ratio (CaO/alkoxy group) is less than 1, the mechanical strength tends to be inferior, and if it exceeds 40, the adhesive strength tends to decrease.
The molar ratio (CaO/alkoxy group) is preferably 2-30, and more preferably 4-15, from the viewpoints of mechanical strength and adhesiveness.

The contents of (A), (B), (C), (D) and (E) in the composition are as follows, based on the total weight of (A), (B), (C), (D) and (E):
From the viewpoints of the handleability of the composition and the physical properties (mechanical strength, etc.) of the cured product, the content of (A) is preferably 40 to 80% by weight, more preferably 45 to 70% by weight, and particularly preferably 50 to 65% by weight.
From the viewpoints of the handleability of the composition and the physical properties (mechanical strength, etc.) of the cured product, the amount of (B) is preferably 10 to 50% by weight, more preferably 15 to 45% by weight, and particularly preferably 20 to 40% by weight.
From the viewpoints of the volume change rate and handleability, the content of (C) is preferably 3 to 40% by weight, more preferably 5 to 30% by weight, and particularly preferably 7 to 20% by weight.
From the viewpoints of volume change rate and physical properties (mechanical strength, etc.), (D) is preferably 0.5 to 7% by weight, more preferably 1 to 6% by weight, and particularly preferably 1.5 to 5% by weight.
From the viewpoint of adhesive strength (particularly adhesive strength on a wet surface), (E) is preferably 0.5 to 5% by weight, more preferably 1 to 4% by weight, and particularly preferably 2 to 3% by weight.

The molar ratio of the epoxy groups in (A) to the active hydrogens in (B) [active hydrogens/epoxy groups] is preferably 0.4 to 2.5, more preferably 0.5 to 2.0, and particularly preferably 0.6 to 1.5, from the viewpoint of the physical properties (mechanical strength) of the cured product.
From the viewpoint of the volume change rate, the weight ratio of (C) to (D) (C/D) is preferably 30/70 to 98/2, more preferably 75/25 to 95/5, still more preferably 80/20 to 92/8, and particularly preferably 85/15 to 90/10.
The molar ratio of calcium oxide to water (D) in the epoxy resin composition (CaO/water) is preferably 0.1 to 5, and more preferably 1 to 4, from the viewpoints of volume change rate and physical properties (mechanical strength).
The weight ratio of (C) to (E) (C/E) is preferably from 1 to 50, more preferably from 2 to 30, and particularly preferably from 6 to 15, from the viewpoints of adhesive strength (particularly adhesive strength on a wet surface) and mechanical strength.

[Ethylene oxide and/or alkylene oxide adduct having 3 to 6 carbon atoms of polyol (F)]
The epoxy resin composition of the present invention may further contain (F) an ethylene oxide (hereinafter abbreviated as EO) and/or alkylene oxide (hereinafter abbreviated as AO) adduct of a polyol. By containing (F), the thixotropy of the epoxy resin composition can be enhanced. Furthermore, the dispersion stability of water (D) in the polyepoxide (A) can be enhanced, and the temporal stability of the epoxy resin composition tends to be improved.
The polyols include dihydric to octahydric or higher polyhydric alcohols (C2-30), dihydric to octahydric or higher polyhydric phenols (C6-40), and mixtures thereof.

Examples of the polyhydric alcohol include dihydric alcohols [e.g., EG, PG, 1,3- or 1,4-butanediol, 1,6-HD, 3-methylpentanediol, diEG, NPG, 1,4-bis(hydroxymethyl)cyclohexane, 1,4-bis(hydroxyethyl)benzene, 2,2-bis(4,4′-hydroxycyclohexyl)propane], trihydric alcohols [e.g., GR, TMP], and tetrahydric to octahydric alcohols [e.g., PE, diGR, α-methylglucoside, SO, xylitol, mannitol, diPE, glucose, fructose, sucrose].
Examples of the polyhydric phenol include dihydric phenols [e.g., hydroquinone, catechol, bisphenol-A, -F and S, naphthalenediol, anthracenediol], trihydric to octahydric or higher phenols [e.g., hydroxyquinol, pyrogallol, trishydroxyphenylisopropylbenzene [trade name "Trisphenol PA", manufactured by Mitsui Petrochemical Co., Ltd.], phenol novolac, cresol novolac], and the like.

Of these polyols, from the viewpoint of the thixotropy of the epoxy resin composition, preferred are polyhydric alcohols, more preferred are di- to tetrahydric C2-10 polyhydric alcohols, and particularly preferred are di- to trihydric C3-6 polyhydric alcohols.
Examples of the AO include 1,2-propylene oxide (hereinafter abbreviated as PO), 1,3-propylene oxide, 1,2-, 2,3- or 1,3-butylene oxide, and 1,2-hexylene oxide. From the viewpoint of the thixotropy of the epoxy resin composition, PO is preferred.

Among (F), from the viewpoint of thixotropy, preferred is a compound obtained by adding both EO and AO (C3-6) to the polyol. When both EO and AO (C3-6) are added, the addition may be in the form of random addition or block addition, but from the viewpoint of thixotropy, random addition is preferred.
The average total number of moles of EO and AO (C3-6) added to the polyol is preferably 3 to 150, and more preferably 15 to 130, from the viewpoints of the thixotropy and handleability of the epoxy resin composition.
The molar ratio of EO to AO (C3-6) added (EO/AO) is preferably 0.2-10, more preferably 0.3-8, and particularly preferably 0.5-7, from the viewpoints of the thixotropy of the composition and the water resistance of the cured product.
From the viewpoints of the thixotropy and handling properties of the epoxy resin composition, the Mn of (F) is preferably from 200 to 10,000, and more preferably from 1,000 to 8,000.

The production of (F), which is an EO and/or AO (C3-6) adduct of polyol, can be carried out by a known method in the presence of a catalyst (alkali catalyst, amine catalyst, acid catalyst) at normal pressure or elevated pressure in one or multiple stages.

The conditions for measuring Mn in the present invention by GPC are as follows.
Equipment: Tosoh Corporation HLC-802A
Column: TSK gel GMH6 x 2 Measurement temperature: 40°C
Sample solution: 0.5% by weight THF solution Injection amount: 200 μl
Detector: Refractive index detector Standard: Polystyrene

The amount of (F) used is preferably 0.1 to 5% by weight, more preferably 0.2 to 3% by weight, and particularly preferably 0.5 to 2% by weight, based on the total weight of the (A), (B), (C), (D) and (E), from the viewpoints of the thixotropy of the epoxy resin composition and the physical properties (mechanical strength, etc.) of the cured product.
The weight ratio (D/F) of (D) to (F) is preferably 0.5 to 14 from the viewpoint of the temporal stability of solution A when the two solutions are stored separately as described below.

[Inorganic filler (G)]
The epoxy resin composition of the present invention may contain an inorganic filler (G) as necessary in order to adjust the physical properties of the cured product (improving the compressive yield strength, compressive elastic modulus, etc.). The (G) is other than the above-mentioned (C), and includes the following (G1) to (G7) and mixtures of two or more of these.
(G1) Silicates (e.g. talc, clay, mica, glass);
(G2) Oxides other than (C) [e.g. titanium oxide, alumina, silica];
(G3) Carbonates (e.g., calcium carbonate, magnesium carbonate, hydrotalcite);
(G4) hydroxides (e.g., aluminum hydroxide, magnesium hydroxide, calcium hydroxide);
(G5) Sulfites (e.g., barium sulfate, calcium sulfate, calcium sulfite);
(G6) Borates (e.g., zinc borate, barium metaborate, aluminum borate, calcium borate, sodium borate);
(G7) Nitrides (e.g., aluminum nitride, boron nitride, silicon nitride).

Of these (G), from the viewpoints of the physical properties (mechanical strength, etc.) of the cured product and from the industrial viewpoint, preferred are (G1), (G2), (G3) and (G4), more preferred are (G1), (G2) and (G3), and particularly preferred are silica and calcium carbonate.

The shape of (G) is preferably a powder from the viewpoint of the handleability of the epoxy resin composition. In addition, the volume average particle size of (G) is preferably 0.1 to 800 μm, more preferably 0.5 to 250 μm, from the viewpoint of the viscosity and handleability of the epoxy resin composition.

The amount of (G) used is preferably 5 to 200% by weight, more preferably 10 to 190% by weight, and particularly preferably 20 to 180% by weight, based on the total weight of (A), (B), (C), (D), and (E), from the viewpoint of the physical properties and handling properties of the cured product.

The epoxy resin composition may further contain, as necessary, (1) curing accelerators (tertiary amino compounds, alkali compounds other than (C) above, Lewis base compounds, etc.), (2) adhesion promoters (titanium coupling agents, etc.), (3) antioxidants (hindered amines, hydroquinones, hindered phenols, sulfur-containing compounds, etc.), (4) ultraviolet absorbers (benzophenones, benzotriazoles, salicylic acid esters, metal complex salts, etc.), (5) plasticizers (phthalates, phosphates, fatty acid esters, epoxidized soybean oil, castor oil, liquid paraffin alkyl polycyclic aromatic hydrocarbons, etc.), (6) waxes (paraffin wax, microcrystalline wax, polymerized wax, beeswax, spermaceti, low molecular weight polyolefins, etc.), and (7) non-reactive agents. (8) reactive diluents (benzyl alcohol, tar, picumen, etc.), (9) organic fillers [aramid fiber powder, nylon fiber powder, acrylic fiber powder, acrylic resin powder, phenolic resin powder, etc.], (10) deodorants [activated carbon, zeolite, etc.], (11) pigments or dyes [carbon black, red lead, para red, Prussian blue, etc.], (12) thixotropic agents [bentonite, hydrogenated castor oil wax, calcium stearate, etc.], (13) solvents (ethyl acetate, toluene, alcohol, ether, ketone, etc.), (14) foaming agents, (15) defoamers, (16) antistatic agents, (17) antibacterial agents, (18) fungicides, (19) viscosity modifiers, (20) fragrances, (21) flame retardants, and other additives (H).

The epoxy resin composition of the present invention is produced by the following method (1) or (2).
(1) (A), (B), (C), (D), (E), and, if necessary, (F), (G), and (H) are mixed together immediately before use to form a composition.
(2) Two liquids [Liquid A containing (A) and Liquid B containing (B)] are separately prepared and mixed at the time of use to form a composition. (C), (D) and (E) are preferably mixed in Liquid A or Liquid B in advance, and more preferably (C) and (E) are mixed in Liquid B and (D) is mixed in Liquid A. In addition, (F) to be added as needed may be mixed in Liquid A and/or Liquid B in advance or at the time of use, but from the viewpoint of thixotropy and handling properties, it is preferable to mix it in Liquid A and/or Liquid B, and from the viewpoint of dispersion stability of water (D) and stability over time of Liquid A, it is preferable to mix it in Liquid A in advance. (G) and (H) to be added as needed are also preferably mixed in Liquid A and/or Liquid B in advance from the same viewpoint.
Of these composition forms, form (2) is preferred from the industrial viewpoint.
In both cases (1) and (2), it is desirable to use (A) and (B), (C) and (D), and (D) and (E) promptly after mixing, because the reaction proceeds after mixing. The pot life of (A), (B), (C), (D), and (E) after mixing is preferably 5 to 180 minutes, more preferably 10 to 90 minutes, when the temperature of each of (A), (B), (C), (D), and (E) is 15 to 35° C.
In this specification, the pot life refers to the time from the start of mixing of each component (total amount 120 g) adjusted to 25° C. until the viscosity of the mixture reaches 100 (Pa s) in a thermostatic chamber at 25° C. after uniform mixing.

In the present invention, examples of a method for mixing (A), (B), (C), (D), and (E), and optionally containing (F), (G), and (H), include a method using a mixer such as a universal mixer and a method using a mixer described later.
The viscosity (Pa·s) of the epoxy resin composition at 25° C. is preferably 20 to 90, more preferably 30 to 85, and particularly preferably 40 to 80, from the viewpoints of preventing dripping and improving handleability.

The viscosity is measured, for example, under the following conditions.
Equipment: BH type viscometer [model number "TVB-22H", manufactured by Toki Sangyo Co., Ltd.]
Rotation speed: 20 rpm
Spindle No.: No. 7

The epoxy resin composition of the present invention has excellent handling properties and excellent physical properties of the cured product, and exhibits very little volume shrinkage or moderate volume expansion during curing. For this reason, it can be used in various applications, such as adhesives, molded products, and grout materials for reinforcing bar joints, and is particularly suitable as a grout material for reinforcing bar joints. The volume shrinkage and volume expansion can be evaluated by the volume change rate (%) before and after curing, which will be described later. The volume change rate is preferably 97 to 110%, more preferably 98 to 105%, and particularly preferably 99 to 103%.
In applications where dimensional stability is particularly desired, the volume change rate is preferably 99 to 101%.

The epoxy resin composition of the present invention has extremely small volumetric shrinkage during curing or moderate expansion during curing, so that it can suppress volumetric shrinkage and has excellent adhesion to wet surfaces. In addition, the effect of the deterioration of physical properties due to the incorporation of silane coupling is small, and a cured product with excellent mechanical strength can be obtained, so it can be preferably used as a civil engineering and construction adhesive (repair and reinforcement work for structures such as concrete structures and steel structures, crack injection, and post-installed anchor adhesive) that may be used in a state where the adhesive surface is wet due to rainfall, etc., and is particularly useful as a post-installed anchor adhesive.
"Post-installed anchor" refers to a construction method used in the fields of civil engineering, architecture, machinery, etc., in which an anchor member such as an anchor bolt or a reinforcing bar is embedded in an already manufactured concrete structure (hereinafter referred to as the base material). The epoxy resin composition of the present invention can be used as an adhesive between the base material and a metal anchor member when embedding the metal anchor member in the base material. Specifically, the anchor member is inserted into a hole drilled in the base material, and the epoxy resin composition of the present invention is poured into the hole, thereby firmly bonding the hole wall and the anchor member.

In addition, since the epoxy resin composition of the present invention has excellent adhesion to wet surfaces, the effect of the moisture content of wood on the adhesive strength is small, and therefore the composition can be preferably used as an adhesive for wood, and is particularly useful as an adhesive for the GIR method.
The "GIR method" is a construction method in which holes are drilled into wood and adhesive is injected and filled into the gap between the holes and a rod-shaped connecting metal fitting inserted into the holes.

The present invention will be further described below with reference to examples, but the present invention is not limited to these. The parts in the examples are by weight.

[Production of EO and/or AO (C3-6) adduct of polyol (F)]
Production Example 1
An autoclave was charged with 30 parts of propylene glycol and 0.15 parts of potassium hydroxide as a catalyst, and a mixture of 693 parts of EO and 277 parts of PO was blown in and reacted at 110° C. After aging at 130° C., the catalyst was removed by adsorption treatment with a magnesium oxide-based adsorbent [product name "Kyoward 600", manufactured by Kyowa Chemical Industry Co., Ltd.] to obtain 992 parts of propylene glycol EO and PO adduct (F-1) (Mn 3,000, average number of moles of EO and PO added 52, EO/PO addition molar ratio = 3.3).

Production of Solution A (Production Examples 2 to 7)
A universal mixer [product name "Universal Mixer 5DMV-01-r", manufactured by Dalton Co., Ltd.] was used to mix according to Table 1 to obtain solution A. 30 g of the obtained solution A was placed in a centrifuge tube (50 mL) and an accelerated test was performed using a centrifuge (2000 rpm x 30 minutes x 4 times, total of 2 hours). The state of the solution after centrifugation was visually confirmed and evaluated according to the following evaluation criteria. The results are shown in Table 1.
○: No separation even after 2 hours △: No separation after 1 hour, but separation after 2 hours ×: Separation after 30 minutes or 1 hour

表１の結果から重量比（Ｄ／Ｆ）が０．７～１４である製造例２～４は、分離しにくく、経日安定性が良好であることが分かる。

The results in Table 1 show that Production Examples 2 to 4, in which the weight ratio (D/F) is 0.7 to 14, are less susceptible to separation and have good stability over time.

Examples 1 to 13 and Comparative Examples 1 to 5
Using a universal mixer [product name "Universal Mixer 5DMV-01-r", manufactured by Dalton Co., Ltd.], liquids A and B were blended according to Table 2 and mixed while degassing under reduced pressure (temperature 25°C, mixing time 5 minutes, pressure 4 kPa) to obtain liquids A and B. Furthermore, using a centrifugal degassing machine [product name "Awatori Rentaro ARV930TWIN", manufactured by Thinky Corporation], liquids A and B were mixed in the weight ratios shown in Table 2 (temperature 25°C, mixing time 3 minutes, rotation speed 1400 rpm) to obtain epoxy resin compositions. The performance of the compositions was evaluated using the following test methods. The results are shown in Table 2.

The abbreviations in Table 2 are as follows.
A-1: Bisphenol F diglycidyl ether [product name "JER807", manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 175]
A-2: Neopentyl glycol diglycidyl ether [product name: "Ex-211", manufactured by Nagase ChemteX Corporation,
Epoxy equivalent 138]
B-1: Xylylenediamine [product name "Ancamine 2422", manufactured by Air Products Japan Co., Ltd.,
Active hydrogen equivalent: 34, number of active hydrogen atoms directly bonded to N atoms: 4]
B-2: 1,3-bisaminomethylcyclohexane [product name "1-3BAC", manufactured by Mitsubishi Gas Chemical Company, Inc.,
Active hydrogen equivalent: 36, number of active hydrogen atoms directly bonded to N atoms: 4]
C-1: Calcium oxide [product name "Taiheiyo Hyper Expan (for structural use)",
Manufactured by Pacific Materials Co., Ltd., calcium oxide content 70% by weight,
Volume average particle diameter 50 μm]
C-2: Calcium sulfoaluminate [product name "Denka Power CSA Type S", manufactured by Denki Kagaku Kogyo Co., Ltd.,
Calcium oxide content: 50% by weight, volume average particle size: 60 μm]
D-1: Ion-exchanged water E-1: N-2-(aminoethyl)-3-aminopropyltrimethoxysilane [product name "KBM-603", manufactured by Shin-Etsu Chemical Co., Ltd.]
E-2: 3-aminopropyltrimethoxysilane [product name "KBM-903", manufactured by Shin-Etsu Chemical Co., Ltd.]
E-3: 3-glycidoxypropyltrimethoxysilane [product name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.]
E-4: 3-mercaptopropyltrimethoxysilane [product name "KBM-803", manufactured by Shin-Etsu Chemical Co., Ltd.]
F-1: Propylene glycol EO/PO random adduct [obtained in Production Example 1, Mn 3,000, average number of moles of EO and PO added 52,
EO / PO addition molar ratio = 3.3]
G-1: Calcium carbonate [product name "Softon 1500", manufactured by Shiraishi Calcium Co., Ltd.,
Volume average particle diameter 1.5 μm]
G-2: Silica [product name: HS-106, manufactured by Micron Co., Ltd., volume average particle diameter 20 μm]

<Test Method>
[Volume change rate before and after curing] (unit: %)
(1) The specific gravity of an epoxy resin composition adjusted to a temperature of 25°C was measured by a pycnometer method in accordance with JIS K0061 using a high-precision electronic specific gravity meter [model number "SD-200L", manufactured by Alpha Mirage Co., Ltd.], and this was recorded as the specific gravity (d1) before curing.
(2) The obtained epoxy resin composition was molded into a plate having a thickness of about 10 mm, and after curing at 25°C for 5 days, a rectangular test piece having a size of about 10 x 10 x 30 mm was cut out. The specific gravity of the test piece, whose temperature had been adjusted to 25°C, was measured by a high-precision electronic specific gravity meter [model number "SD-200L", manufactured by Alpha Mirage Co., Ltd.] according to JIS K0061 using a balance method, and this was recorded as the specific gravity after curing (d2).
(3) The volume change rate was calculated from the specific gravity before curing (d1) and the specific gravity after curing (d2) according to the following formula (1). If the volume change rate is less than 100%, the composition has shrunk, and if it is greater than 100%, the composition has expanded.
[Volume change rate before and after curing (%)] = (1/d2) × 100/(1/d1) (1)
d1: Specific gravity before curing d2: Specific gravity after curing

[Compressive yield strength (compressive yield stress), compressive elastic modulus (compressive elastic modulus)] (units: N/mm ² for both)
The kneaded epoxy resin composition was molded into a plate having a thickness of about 10 mm, and cured by aging at 25° C. for 5 days. A rectangular test piece having a thickness of about 10 mm, a width of about 10 mm, and a length of about 30 mm was cut out, and measurements were performed in accordance with JIS K7181, except that the test speed was changed to 2 mm/min.

[Adhesive strength between steel plates (lap shear adhesive strength)] (unit: N/mm ² )
A cold-rolled steel plate of about 1.6 mm thick, about 25 mm wide, and about 100 mm long as specified in JIS G3141 was washed with acetone, and two cold-rolled steel plates were bonded together with a kneaded epoxy resin composition so that the overlap length was 12.5 mm and the thickness of the adhesive layer was 0.2 mm to obtain a test piece. The test piece was aged at 25°C for 5 days, and then the adhesive strength of the normal surface (lap shear adhesive strength) was measured at a test speed of 10 mm/min in accordance with JIS K6850.
The adhesive strength of the wet surface (lap shear adhesive strength) was measured in the same manner as for the normal surface, except that two cold-rolled steel sheets, which had been washed with acetone and then placed overnight in a high-temperature, high-humidity chamber (75°C, 95%), were bonded with an epoxy resin composition immediately after removal from the chamber to obtain a test piece. The lap shear adhesive strength values shown in Table 2 are the average values of the results of five tests.

[Adhesive strength between wood pieces (compressive shear adhesive strength)] (unit: N/mm ² )
<Normal Test>
A test piece was obtained by bonding two 25mm x 30mm x 15mm thick white wood sheets to each other with a kneaded epoxy resin composition so that the thickness of the adhesive layer was 0.2mm. After curing at 25°C for 5 days, the compressive shear bond strength was measured at a test speed of 2mm/min according to JIS K6852. In addition, the state of breakage in the adherend when the test piece broke was examined, and the percentage of the broken area relative to the shear area was read to obtain the wood breakage rate (unit: %), which is shown in parentheses. The values of compressive shear bond strength and wood breakage rate shown in Table 2 are the average values of the results of five tests.
<Hot water resistance test>
Test pieces were obtained in the same manner as in the normal test and aged for 5 days at 25° C. The test pieces were immersed in warm water at 60° C. for 3 hours, and then immersed in water at room temperature until they cooled, and tested in the wet state.
<Repeated boiling test>
Test pieces were obtained in the same manner as in the normal test and aged at 25°C for 5 days. The test pieces were immersed in boiling water for 4 hours, then dried in air at 60°C for 20 hours, and then immersed in boiling water for another 4 hours. After this treatment, they were immersed in water at room temperature until they cooled, and tested in a wet state.

From the results in Table 2, it is understood that the epoxy resin compositions of Examples 1 to 13 can suppress volumetric shrinkage during curing, and can give cured products having excellent adhesion to wet surfaces and excellent mechanical strength.
On the other hand, when comparing Comparative Example 1, which is the same except that the expansion agent (C) is not used, with Example 1, it is found that the volume change due to curing is large, the adhesion is low, and the adhesion is particularly poor under wet conditions. When comparing Comparative Example 2, which is the same except that the silane coupling agent (E) is not used, with Example 1, it is found that the volume change due to curing is large, the adhesion is low, and the adhesion is particularly poor under wet conditions. In addition, Comparative Example 3, which uses a large amount of silane coupling agent (E), has the same or higher adhesion compared to Example 7, which is the same except that the expansion agent (C) is used, but the volume change due to curing is large and the mechanical strength (compressive yield strength, compressive elastic modulus) is extremely low. In addition, Comparative Example 4, which has a molar ratio (CaO/alkoxy group) of less than 1, has the same volume shrinkage as Example 1, but has poor adhesion and extremely poor mechanical strength. In addition, Comparative Example 5, which has a molar ratio (CaO/alkoxy group) of more than 40, has the same mechanical strength as Example 6, but has a large volume change and extremely low adhesion.

The epoxy resin composition of the present invention can suppress the volumetric shrinkage of the epoxy resin composition when cured, and can obtain a cured product having excellent adhesion to wet surfaces and excellent mechanical strength, and therefore can be used for repair and reinforcement of structures such as concrete structures and steel structures, crack injection, and post-installed anchor adhesives, and is particularly useful as a post-installed anchor adhesive. It can also be preferably used as a wood adhesive, and is particularly useful as an adhesive for the GIR method.

Claims (6)

1. An epoxy resin composition comprising a polyepoxide (A), a polyamine (B) having 2 to 50 active hydrogen atoms directly bonded to N atoms, an expanding agent (C), water (D) and a silane coupling agent (E), wherein the expanding agent (C) contains calcium oxide, the silane coupling agent (E) is a compound having at least one alkoxy group bonded to a silicon atom and at least one functional group selected from the group consisting of an amino group, a mercapto group and an epoxy group, and the molar ratio (CaO/alkoxy group) of the calcium oxide in the expanding agent (C) to the alkoxy group bonded to a silicon atom in the silane coupling agent (E) is 1 to 40, and the epoxy resin composition is an adhesive for civil engineering and construction . The epoxy resin composition according to claim 1, wherein the content of the silane coupling agent (E) is 0.5 to 5% by weight based on the total weight of (A), (B), (C), (D) and (E). The epoxy resin composition according to claim 1 or 2, which contains (F) an ethylene oxide and/or alkylene oxide adduct having 3 to 6 carbon atoms of a polyol. The epoxy resin composition according to claim 3, wherein the weight ratio (D/F) of the water (D) to the alkylene oxide adduct (F) is 0.5 to 14. The epoxy resin composition according to any one of claims 1 to 4, wherein the molar ratio (CaO/water) of calcium oxide to water (D) in the epoxy resin composition is 0.1 to 5. A cured product obtained by curing the epoxy resin composition according to any one of claims 1 to 5 .