JPH11209459A - Epoxy resin curing agent, resin composition, preparation of cured product and cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve mechanical strength, chemical resistance and water resistance by admixing a specific curing agent for an epoxy resin with a polyepoxy compound. SOLUTION: A curing agent (A) for an epoxy resin comprising a mercapto compound having a mercaptan equivalent of 10-1,000, preferably 100-400, of the formula (wherein n is not less than 5; X is a residue obtained by removal of n active hydrogen atoms from a compound having five or more active hydrogen atoms selected from polyglycerols and compounds obtained by the addition of not more than 10 monoepoxy compounds per hydroxyl group to a part or all of the hydroxyl groups of a polyglycerol) is admixed with a polyepoxy compound (B), a basic material and/or a compound having a phenolic hydroxyl group, if necessary, as a curing accelerator (C) and a pot life adjusting agent (D) selected from a compound having at least one carboxyl group in the molecule and a Lewis acid (an amine complex salt), in an amount such that the ratio of mercaptan equivalent of the component A to the epoxy equivalent of the component B is 1/(0.5-2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin curing agent, an epoxy resin composition, a method for producing an epoxy resin cured product, and an epoxy resin cured product. More specifically, an epoxy resin curing agent that quickly cures at room temperature, has good low-temperature curability, and has excellent mechanical properties, chemical resistance and water resistance of the cured product, and an epoxy resin composition using the curing agent And a method for producing a cured product using the composition and a cured product.

[0002]

2. Description of the Related Art For repair work in the field of civil engineering and construction, it is often necessary to accelerate the construction period or work under cold conditions.
Often requires fast curability. As an epoxy resin curing agent used for curing a polyepoxy compound, a mercapto-based curing agent having low-temperature curability and high-speed curability has attracted attention and has been gradually put into practical use. As the mercapto-based curing agent, for example, the following are known. Polymercaptocarboxylic acid esters of polyhydric alcohols such as trimethylolpropane (JP-A-61-16251)
7 etc.) Polymercaptan derived from di- or triglycidyl ether of oxyalkylene ether of trimethylolpropane (JP-B-47-48279 etc.) Tetrafunctional polymercaptan derived from diaminetetraglycidylated product (US Pat. No. 4,879,414, U.S. Pat.
(SP4927902 specification etc.)

[0003]

However, there is a problem that the ester group in the molecule deteriorates the chemical resistance of the cured product, especially the alkali resistance. There is a problem that physical properties such as water resistance and water resistance are insufficient, so that the use of mercapto-based curing agents is still limited in physical properties.

[0004]

Means for Solving the Problems The present inventors have maintained the low-temperature curability and high-speed curability of a mercapto-based curing agent at levels higher than those of conventional products, and have obtained the mechanical strength, chemical resistance, and water resistance of a cured resin. As a result of diligent studies in order to obtain a mercapto-based curing agent having improved properties, the present invention has been achieved. That is, the present invention provides an epoxy resin curing agent comprising a mercapto compound (A) represented by the following general formula (1);
An epoxy resin composition comprising the curing agent and the polyepoxy compound (B); a method for producing a cured epoxy resin characterized by curing the composition; and an epoxy produced by curing the composition. It relates to a cured resin. [In the formula, n is an integer of 5 or more, X is selected from the following (a1) and (a2), and a residue obtained by removing n active hydrogens from a compound (a) having 5 or more active hydrogens. Represent. (A1) Polyglycerin (a2) Compound in which not more than 10 monoepoxy compounds (b) have been added to some or all of the hydroxyl groups of (a1)]

In the above general formula (1), n is 5 or more;
It preferably represents an integer of 5 to 12. When n is less than 5, tensile strength, compression strength, mechanical strength such as bending strength, water resistance and acid resistance, alkali resistance of the epoxy resin cured product,
Insufficient chemical resistance such as solvent resistance and oil resistance. X is n
Since it is a residue obtained by removing n active hydrogens from the compound (a) having at least active hydrogens, the compound (a) has at least 5 active hydrogens.

The compound (a) is a compound of the above (a1) and (a)
2). Polyglycerin (a1)
In the above, since polyglycerin having 3 repeating units has 5 active hydrogens, it is necessary to use polyglycerin having 3 or more repeating units as (a1). Therefore,
As polyglycerin (a1), as long as it has a repeating unit of 3 or more, it can be a commonly available one,
It is not affected by its manufacturing method or structure. The repeating unit of polyglycerin (a1) is usually 3 to 14, preferably 4 to 10. Since polyglycerol having 10 repeating units has 12 active hydrogens, for example, in order to obtain a compound of general formula (1) in which n is 12, use is made of (a1) using polyglycerin having 10 or more repeating units. (A
As 2), a compound in which a monoepoxy compound (b) is added to polyglycerin having 10 or more repeating units may be used.

Examples of the monoepoxy compound (b) in (a2) include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, α-olefin oxide, epichlorohydrin,
Examples include alkylene (arylene) oxides such as epibromohydrin, and monoglycidyl ether compounds such as butyl glycidyl ether, phenyl glycidyl ether, and 2-ethylhexyl glycidyl ether. Two or more monoepoxy compounds may be used in combination, and the addition form may be either block or random.

The number of monoepoxy compounds (b) to be added to a part or all of the hydroxyl groups of (a1) to give (a2) is not more than 10 on average per one hydroxyl group. , And the number added to one is 10 on average
If the number exceeds the above, the crosslinked structure of the cured product becomes loose, the hydrophilicity of the cured product increases, the molecular weight between crosslink points increases, etc., so that the mechanical properties, chemical resistance, water resistance, etc. of the cured product Physical properties are deteriorated. By changing the type, addition form and amount of the monoepoxy compound (b), the viscosity of the mercapto compound (A), the compatibility with the polyepoxy compound (B) used as the main ingredient, the flexibility of the cured product, the hardness, etc. Properties can be controlled.

As a method for adding the monoepoxy compound (b) to the hydroxyl group of the polyglycerin (a1), the monoepoxy compound (b) is stirred with stirring in the presence of the polyglycerin (a1) and an alkali catalyst in an autoclave. The method of putting in is taken. Temperature is usually 100-200
° C, preferably from 120 to 170 ° C. Pressure is usually 1
10 to 10 kg / cm ² , preferably 3 to 7 kg / cm ² . After the introduction of the monoepoxy compound (b), the mixture is aged, filtered using activated clay or the like, and the remaining alkali catalyst is adsorbed and removed for purification.

The mercapto compound (A) is prepared, for example, by adding n or more epichlorohydrins to the compound (a) in the presence of an alkali catalyst and subjecting the polyepoxy compound obtained by dehydrochlorination to an addition reaction with hydrogen sulfide. Can be synthesized by As a method of converting the compound (a) into a polyepoxy compound, a method of dropping granular caustic soda while mixing and stirring the compound (a), epihalohydrin, and a phase transfer catalyst is usually employed. As the epihalohydrin, epichlorohydrin or epibromohydrin is usually used, and preferably epichlorohydrin. As the phase transfer catalyst, ordinary quaternary ammonium salts can be used. The molar ratio of the compound (a) to the epihalohydrin is such that the hydroxyl group of the compound (a) /epihalihydrin=1.0/1.0-1.0/5.0, more preferably 1.0 / 1.5-1. 0.0 / 3.0. The reaction temperature is usually 20-40 ° C, preferably 25-35 ° C. After the completion of the dropwise addition and the ripening, the excess alkali and by-produced salts are removed by washing with water, and the excess epihalohydrin is distilled off.
Further, a trace amount of the remaining alkali is subjected to adsorption treatment with activated clay or the like, followed by filtration and purification to obtain the polyepoxy compound of the compound (a).

As a specific method for obtaining a mercapto compound (A) by adding hydrogen sulfide to a polyepoxy compound of compound (a), a part of hydrogen sulfide in a total amount used in an autoclave and a solvent and a catalyst Are charged in advance, and the polyepoxy compound of the compound (a) and the remaining hydrogen sulfide are charged with stirring. The amount of hydrogen sulfide to be used is usually 100 to 200 mol%, preferably 101 to 110 mol%, in mol% based on the epoxy group of the polyepoxy compound of compound (a). When the amount is less than 100 mol%, the amount of cross-linked products increases due to the reaction between the generated mercapto compound (A) and the polyepoxy compound of the remaining compound (a), and when it exceeds 200 mol%, excess hydrogen sulfide is removed. Requires high cost. The amount of hydrogen sulfide charged in advance should be set to approximately 80% of the upper pressure limit,
The remainder is charged within the pressure and temperature control ranges.

The solvent is not particularly limited as long as it dissolves the polyepoxy compound of compound (a), hydrogen sulfide, and the catalyst and does not inhibit the reaction. Alcohols, ketones, and esters are usually usable. Preferably alcohols, among which methanol, ethanol,
Isopropyl alcohol and the like are preferred. The amount of the solvent to be used is generally 50 to 500%, preferably 100 to 300% by weight based on the polyepoxy compound of the compound (a). A part of the solvent may be used for reducing the viscosity of the polyepoxy compound of the compound (a) to be dropped. As the catalyst, tertiary amines, caustic soda, caustic potash and the like are usually used, and tertiary amines are preferable, and among them, trimethylamine, triethylamine and the like are preferable from the viewpoint of easy removal. The amount used is usually 0.05 to 5.0% by weight based on the polyepoxy compound of compound (a).
Preferably it is 0.1-3.0%.

[0013] The reaction temperature is usually 0 to 50 ° C, preferably 20 to 30 ° C. If the temperature falls below 0 ° C., the reaction slows down.
When the temperature exceeds 50 ° C., side reactions increase. The reaction pressure is usually 1 to 10 kg / cm ² , preferably 1.5 to 5 kg / c.
m ² . The reaction time is not particularly limited as long as the setting range of the reaction temperature and the reaction pressure can be maintained. After completion of the reaction, excess hydrogen sulfide is expelled from the reaction vessel using a nitrogen solution or the like into an alkaline aqueous solution to be absorbed and removed. Then, methanol and the catalyst are distilled off under reduced pressure, and the resultant is filtered through a wire mesh to remove the mercapto compound (A). obtain.

For preservation of the mercapto compound (A), it is preferable to remove the dissolved oxygen as much as possible by bubbling with nitrogen or reducing the pressure, and then to replace the inside of the container with nitrogen.

When the curing agent of the present invention comprising the mercapto compound (A) is used, the mechanical strength of the cured epoxy resin,
Physical properties such as water resistance and chemical resistance are particularly good. The reason for this is not necessarily clear, but is presumed to be due to the following structural features in addition to the following. Compound (A) has as many as 5 or more thiol groups. There is no ester bond in (A). (A) is a structure having a chain structure and / or a repeating unit, and thus has a structural feature in which thiol-containing groups are present at different positions in the main chain. By this action,
(A) and the polyepoxy compound (B), the number of crosslinking points in the cured resin having a three-dimensional network structure increases,
A dense crosslinked structure is formed.

When producing the mercapto compound (A),
The mercaptan equivalent (molecular weight / the number of thiol groups) can be easily adjusted by changing the type of the compound (a) and the thiolation rate of the hydrogen sulfide addition reaction. The mercaptan equivalent of the compound (A) is preferably from 100 to 1,000, and particularly preferably from 100 to 400. When the mercaptan equivalent is more than 1000, the physical properties of the cured epoxy resin composition such as hardness and water resistance are deteriorated, while it is difficult to synthesize a product having a mercaptan equivalent smaller than 100. As a component in the curing agent of the present invention,
Other known polythiol compounds may be used in combination as long as the properties of the mercapto compound (A) are not hindered.

The epoxy resin composition of the present invention comprises the curing agent of the present invention comprising the mercapto compound (A) and the polyepoxy compound (B). It is a two-part with the polyepoxy compound (B) -containing main ingredient, and both parts are mixed at the time of use.

Examples of the polyepoxy compound (B) include the following (B1) to (B6), but there is no particular limitation as long as the epoxy compound has an epoxy group capable of reacting with active hydrogen of a thiol group. Absent. (B1) bisphenol A, halogenated bisphenol A, bisphenol B, bisphenol AD, bisphenol F, halogenated bisphenol F, resorcinol, hydroquinone, pyrogallol, catechol, 4,
Epichlorohydrin is added to polyhydric phenols such as 4'-dihydroxybiphenyl, 1,5-hydroxynaphthalene, etc.
(B2) polyglycidyl ester compound type polyepoxy compound, (B3) polyglycidylamine, a polyepoxy compound obtained by adding an equivalent amount or more, or a polyphenol type epoxy resin compound such as a phenol novolak type, a brominated novolak type, a cresol novolak type Compound type polyepoxy resin compound, (B4) hydrogenated bisphenol A, ethylene glycol, propylene glycol, tetramethylene glycol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, 2,2
A polyepoxy compound obtained by adding epichlorohydrin to a polyhydric alcohol such as dimethylolpropane, trimethylolpropane, pentaerythritol, dipentaerythritol, or sorbitol in an amount of at least 2 equivalents; Heterocyclic polyepoxy compound

The following basic substance (C) and / or compound (D) having a phenolic hydroxyl group may be added to the composition of the present invention as a curing reaction accelerator. Basic substance (C): Basic substance selected from the group consisting of amines (C1), compounds (C2) having a protected amino group which can be converted to a free amino group by hydrolysis, and phosphines (C3). The following are specific examples of ()). -N-butylamine, isobutylamine, ethylenediamine, propylenediamine, hexamethylenediamine,
Aliphatic amines such as 2,5-dimethylhexamethylenediamine, trimethylhexamethylenediamine, diethylaminopropylamine, methyliminobispropylamine, dimethylaminopropylamine, diethylaminopropylamine, tri (methylamino) hexane or polyetherdiamine・ Polyethylenepolyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, etc. ・ Mensenediamine, bis (aminomethyl) cyclohexane, bis (4-amino-3-methyldicyclohexyl) methane, diaminodicyclohexylmethane, isophorone Alicyclic amines such as diamine, norbornanediamine, N-aminoethylpiperazine, etc. ・ aniline, diaminodiphenylmethane, dia Aromatic amines such as nodiphenylsulfone and diaminodiethyldiphenylmethane. Aliphatic aromatic amines such as m-xylylenediamine. Cyclic amines such as piperazine and piperidine. Condensation of polyethylenepolyamines with polymerized fatty acids (dimer acid). Polyamidoamines such as reaction products Triethylamine, tributylamine, diethylbutylamine, N, N-dimethylpropylamine, N, N,
Aliphatic tertiary amines such as N ′, N′-tetramethylhexamethylenediamine ・ N-methylpyridine, N-methylpyrrolidine, N,
Cyclic tertiary amines such as N'-dimethylpiperazine 1,8-diazabicyclo (5,40) undecene-
7,1,5, -diazabicyclo (4,3,0) nonene-
Alicyclic tertiary amines such as 5,6-dibutylamino-1,8-diazabicyclo (5,4,0) undecene-7 ・ benzyldimethylamine, dimethylaminomethylphenol, 2,4,6-tris (dimethyl Aminomethyl)
Aliphatic aromatic tertiary amines such as phenol

Compound (C2) having the above protected amino group
Examples thereof include ketimine compounds and oxazolidine compounds. The ketimine compound is synthesized by a known method of reacting an amine having a primary amino group with a ketone or aldehyde such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, acetaldehyde, propionaldehyde under dehydration conditions. Can be. Oxazolidines can be synthesized by a known method of reacting amines having a hydroxyalkylamino group with ketones or aldehydes such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, acetaldehyde, and propionaldehyde under dehydration conditions. it can. Specific examples of the phosphines (C3) include triethylphosphine, tributylphosphine, triphenylphosphine and the like.

When the basic substance (C) is added for the purpose of increasing the curing speed, various tertiary amines having a strong basicity in the above (C1) are preferable, and the mechanical properties of the cured product,
In order not to reduce physical properties such as water resistance and chemical resistance, amines having a primary or secondary amino group having an active hydrogen capable of reacting with an epoxy group are preferred. When it is desired to extend the pot life of the composition after blending the main component and the curing agent component, the polyamideamines (C1), the compound (C2) having a protected amino group, the phosphines ( C3) is preferred. When an unprotected primary or secondary amino group is present in the compound (C2) having a protected amino group, the amino group is converted into a monoepoxy compound, an isocyanate compound, an acid anhydride, acrylonitrile, acrylic It is preferable to react with an acid, an acrylic acid ester or the like in order to extend the pot life. The composition to which the compound (C2) having a protected amino group is added as a curing accelerator is used to convert the mercapto compound (A) in the curing agent component after a free amino group is generated by hydrolysis with moisture in the atmosphere at the time of use. Since activation activates and delays the start of the curing reaction by the time required for the hydrolysis reaction, the pot life of the composition can be adjusted.

Examples of the compound (D) include phenol,
Octylphenol, nonylphenol, bisphenol A, bisphenol B, bisphenol AD, bisphenol F, resorcinol, hydroquinone, pyrogallol, catechol, naphthol, cresol, 4,
Examples include 4′-dihydroxybiphenyl, 1,5-hydroxynaphthalene, and the like, and compounds obtained by condensing these compounds with formalin. By changing the type and amount of the basic substance (C), the curing speed, pot life, physical properties of the cured product, and the like can be controlled in accordance with the use, purpose of use, and use conditions. These basic substances may be used in combination.

Basic substance (C) and / or compound (D)
May be added to the curing agent component in advance, or may be added as a third component at the time of use. When added to the curing agent component in advance, the curing speed generally becomes the highest, and when added as a third component at the time of use, the pot life can be prolonged by an amount corresponding to the delay in the activation of the thiol group. (C) and (D) can be used alone or in combination, but it is preferable to use them together in order to further increase the curing speed.

In the composition of the present invention, if necessary, the compound (E1) having one or more carboxyl groups in the molecule and the Lewis acids (E2) are adjusted to prevent the pot life of the composition from becoming too short. ) And amine complex salts of Lewis acids (E3). Compound (E1) includes formic acid, acetic acid, propionic acid, butyric acid, lactic acid, acrylic acid, methacrylic acid, octylic acid, oleic acid, linoleic acid, stearic acid, oxalic acid, malonic acid, succinic acid, benzoic acid, and phthalic acid , Trimellitic acid, pyromellitic acid, salicylic acid, tartaric acid, sebacic acid, citric acid, dimer acid,
Examples thereof include acid anhydrides and mercaptoalkyl acids.
Examples of the Lewis acids (E2) include boron trifluoride, aluminum trichloride, iron trichloride and the like. Examples of the Lewis acid amine complex salts (E3) include complex salts of (E2) with triethylamine, tributylamine and the like. The method of adding the pot life regulator (E) to the composition and the method of using the same are the same as in (C) and / or (D). or,
(E) may be used in combination with (C) and / or (D).

For preservation of the curing agent of the present invention comprising the mercapto compound (A), it is preferable to remove as much dissolved oxygen as possible by a method such as nitrogen bubbling or reduced pressure, and then to replace the inside of the container with nitrogen.

The proportion of each component in the composition of the present invention is usually 5 to 200 parts by weight, preferably 100 parts by weight of the mercapto compound (A), preferably 100 parts by weight of the polyepoxy compound (B). It is 30 to 100 parts by mass. When the basic substance (C) is added, the amount is usually not more than 100 parts by mass, preferably 0.5 to 50 parts by mass, and the compound (D)
Is usually not more than 50 parts by mass, preferably 0.1 to 40 parts by mass, and the amount of the pot life modifier (E) is usually not more than 10 parts by mass, preferably not more than 10 parts by mass. Is 0.01 to 5 parts by mass.

In the composition of the present invention, a curing agent component or a main component component may contain a dehydrating agent, a filler, a plasticizer, an antioxidant, an ultraviolet absorber, an adhesion improver, if necessary, depending on the purpose and use. , Thixotropic agent, filler, coupling agent,
Various additives such as a solvent, a reactive diluent, a pigment, a dispersant, a flame retardant, a conductivity-imparting agent, and a thickener may be arbitrarily compounded.

[0028]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. Parts and% represent parts by mass and% by mass, respectively. Synthesis Example 1 An autoclave was charged with 1000 parts of polyglycerin tetramer (manufactured by Daicel Chemical; glycerin 04) and 0.20 part of caustic potassium, and after dehydration at 100 ° C. × 10 mmHg × 2 hours, propylene oxide (hereinafter abbreviated as PO) 1330
150 ° C × while maintaining the pressure of 4-5 kg / cm ²
Charged over 5 hours. After charging, aged for 4 hours at the same temperature, then cooled to 40 ° C and Kyoward 600
(Manufactured by Kyowa Chemical Industry Co., Ltd.) was charged in an amount of 10 parts, subjected to an adsorption treatment, and purified by filtration to obtain a PO adduct of polyglycerin POA-1. POA-1 has a hydroxyl value of 465 and a number average molecular weight of 74.
2. The viscosity was 2,800 cP (measured at 25 ° C. with a B-type viscometer). After 1,000 parts of POA-1, 1897 parts of epichlorohydrin, and 30 parts of benzyltrimethylammonium chloride are charged into a reaction vessel, 820 parts of granular sodium hydroxide is added thereto over 5 hours while maintaining the temperature at 30 ° C. or lower. Aged for hours. The contents were transferred to a separatory funnel and washed three times with 1,000 parts of water. Then, the remaining epichlorohydrin was distilled off under reduced pressure, 15 parts of Kyoward 600 was added, the mixture was subjected to adsorption treatment, and the intermediate product was filtered. POA
GE-1 was obtained. The intermediate product POAGE-1 has an epoxy equivalent of 166, a number average molecular weight of 933, and a viscosity of 1900 cP.
(Measured by a B-type viscometer at 25 ° C.). After 800 parts of methanol, 20 parts of triethylamine and 68 parts of hydrogen sulfide are charged into an autoclave purged with nitrogen, 1000 parts of an intermediate POAGE-1 and 80 parts of methanol are added.
0 parts of the melt and 159 parts of hydrogen sulfide were charged from different inlets while stirring at a reaction temperature of 25 ° C. and a pressure of 4 kg / cm ² . After adding, 3 more at the same temperature
After aging for 30 hours, the remaining hydrogen sulfide in the container is
% Caustic soda aqueous solution and removed. Further, methanol and triethylamine were distilled off under flowing nitrogen at 100 ° C. × 20 mmHg × 4 hours, and filtered through a 200-mesh stainless steel wire mesh to obtain a polymercaptan compound [1]. The polymercaptan compound [1] was a yellow-brown viscous liquid having a number average molecular weight of 1125, a viscosity of 34000 cP (measured with a B-type viscometer) and a mercaptan equivalent of 205.

Synthesis Example 2 An autoclave was charged with 1000 parts of polyglycerin (hexamer; manufactured by Sakamoto Yakuhin Kogyo; polyglycerin # 500) and 0.20 part of caustic potash, dehydrated at 100 ° C. × 10 mmHg × 2 hours, and then propylene oxide. 1105 parts (hereinafter abbreviated as PO) were charged at 150 ° C. × 5 hours while maintaining a pressure of 4 to 5 kg / cm ² . After charging, the mixture was aged at the same temperature for 4 hours, cooled to 40 ° C., charged with 10 parts of Kyoward 600 (manufactured by Kyowa Chemical Industry Co., Ltd.), adsorbed, filtered and purified, and PO adduct of polyglycerin PO was added.
A-2 was obtained. POA-2 had a hydroxyl value of 455, a number average molecular weight of 980, and a viscosity of 4,200 cP (measured at 25 ° C. using a B-type viscometer). After 1000 parts of POA-2, 2283 parts of epichlorohydrin and 30 parts of benzyltrimethylammonium chloride are charged into a reaction vessel, 987 parts of granular sodium hydroxide is added thereto over 5 hours while maintaining the temperature at 30 ° C or lower, and 3 hours at 30 ° C. Aged for hours. The contents were transferred to a separatory funnel and washed three times with 1000 parts of water. Then, the remaining epichlorohydrin was distilled off under reduced pressure, 15 parts of Kyoward 600 was charged, the mixture was subjected to adsorption treatment, and the mixture was filtered. POAGE-2 was obtained. Intermediate product POAGE-2
Was a compound having an epoxy equivalent of 167, a number average molecular weight of 1,264, and a viscosity of 3,200 cP (measured at 25 ° C. with a B-type viscometer). In a nitrogen-purged autoclave, add methanol 8
After charging 00 parts, 20 parts of triethylamine, and 57 parts of hydrogen sulfide, 1000 parts of the intermediate POAGE-2, 800 parts of methanol, and 171 parts of hydrogen sulfide were charged through separate inlets at a reaction temperature of 25 ° C. and a pressure of 25 parts. 4 kg / cm ²
Was added while stirring. After charging, the mixture was aged for 3 hours at the same temperature, and the remaining hydrogen sulfide in the container was removed by introducing into a 30% aqueous solution of sodium hydroxide with nitrogen. Further, nitrogen is passed through the liquid at 100 ° C. × 20 mmHg ×
Over 4 hours, methanol and triethylamine are distilled off,
The polymercaptan compound [2] was obtained by filtration through a 200 mesh stainless steel wire mesh. The polymercaptan compound [2] has a number average molecular weight of 1500 and a viscosity of 42,000 cP
(Measured with a B-type viscometer at 25 ° C.), mercaptan equivalent 20
7 was a yellowish brown viscous liquid.

Synthesis Example 3 In an autoclave, 1000 parts of polyglycerin (10-mer; manufactured by Asahi Denka; K-COL-IV700) and 0.1 part of potassium hydroxide were added.
20 parts were charged and dehydrated at 100 ° C. × 10 mmHg × 2 hours, and then propylene oxide (hereinafter abbreviated as PO) 1
836 parts while maintaining a pressure of 4-5 kg / cm ²
Charged at 0 ° C. × 5 hours. After charging, the mixture was aged at the same temperature for 4 hours, cooled to 40 ° C., charged with 10 parts of Kyoward 600 (manufactured by Kyowa Chemical Industry Co., Ltd.), adsorbed, filtered and purified, and polyglycerin PO adduct POA-3 was added.
I got POA-3 had a hydroxyl value of 310, a number average molecular weight of 2,200, and a viscosity of 6,300 cP (at 25 ° C., measured with a B-type viscometer). After charging 1000 parts of POA-3, 1807 parts of epichlorohydrin, and 30 parts of benzyltrimethylammonium chloride into a reaction vessel, 781 parts of granular sodium hydroxide is added over 5 hours while keeping the temperature at 30 ° C or less, and 3 hours at 30 ° C. Aged for hours. The contents were transferred to a separatory funnel and washed three times with 1000 parts of water, and the remaining epichlorohydrin was distilled off under reduced pressure.
00, and the mixture was subjected to adsorption treatment and filtration to obtain an intermediate product POAGE-3. The intermediate product POAGE-3 is
Epoxy equivalent 229, number average molecular weight 2550, viscosity 4
The compound had a cP of 900 cP (measured at 25 ° C. with a B-type viscometer). In a nitrogen-purged autoclave, add methanol 80
After charging 0 parts, 20 parts of triethylamine and 58 parts of hydrogen sulfide, 1000 parts of the intermediate POAGE-3, 800 parts of methanol and a solution of 108 parts of hydrogen sulfide, and 108 parts of hydrogen sulfide were charged through separate inlets at a reaction temperature of 25 ° C. and pressure. It was charged under stirring while maintaining 4 kg / cm ² . After the addition, the mixture was aged for 3 hours at the same temperature, and the remaining hydrogen sulfide in the container was introduced into a 30% aqueous sodium hydroxide solution with nitrogen to remove the remaining hydrogen sulfide.
Further, methanol and triethylamine were distilled off at 100 ° C. × 20 mmHg × 4 hours under flowing nitrogen in the liquid, and 20
The mixture was filtered through a 0-mesh stainless steel wire mesh to obtain a polymercaptan compound [3]. The polymercaptan compound [3] has a number average molecular weight of 2930 and a viscosity of 65,000 cP.
(Measured with a B-type viscometer at 25 ° C.), mercaptan equivalent 27
It was a yellow-brown viscous liquid of 2. In addition, the number average number of functional groups is the number average of the number of functional groups contained in one compound molecule.

Examples 1 to 3, Comparative Examples 1 and 2 As Examples 1 to 3, polymercaptan compounds [1] to
[3] A bisphenol A type polyepoxy compound: Epicoat 828 (epoxy equivalent: 190; manufactured by Yuka Shell Epoxy Co., Ltd.) and a curing accelerator: 2,4,6-
The working life, curability, mechanical properties, chemical resistance and water resistance of the mixture when mixed with tris (dimethylaminomethyl) phenol were evaluated by the following methods. Comparative Example 1 used dipentaerythritol hexathioglycolate (comparative polymercaptan compound [4]; manufactured by Nagase Kasei Kogyo; mercaptan equivalent 122) instead of polymercaptan compounds [1] to [3]. In Example 2, the same evaluation was performed using Cup Cure 3-800 (comparative polymercaptan compound [5], manufactured by Hoechst, mercaptan equivalent 280). The mixing ratio is 1: 1 in equivalent ratio.
With respect to epicoat 828: 190 parts, polymercaptan compounds [1] to [5] are respectively 205, 207 and 27.
2,122,280 parts and 2,4,6-tris (dimethylaminomethyl) phenol 5 parts. Table 1 shows the evaluation results of the polymercaptan compounds [1] to [5]. <Evaluation method> Pot life: Immediately after compounding 100 g of each compound, put it in a thermostat at the test temperature, record the temperature rise due to the curing reaction with a thermometer, and set the test temperature to To ° C and the maximum temperature to Tm ° C. The center temperature of the formulation is ΔTo + (Tm−To) /
The time to reach 3 ° C was defined as the pot life. Curability: 300 μm of the compound immediately after compounding on a glass plate
, The test temperature was kept constant, and the time when the surface was free of tack was defined as the touch dry time. Mechanical properties: According to JIS K-7113, the above composition was cured at room temperature for 7 days, and the tensile strength was measured at room temperature. Chemical resistance and water resistance: The above-mentioned composition was cast into a disc having a radius of 12 mm and a thickness of 8 mm, and cured at room temperature for 7 days. It was immersed for 7 days and its mass change was measured. The mass change is
Unless otherwise indicated, it represents an increase in mass.

[0032]

[Table 1]

Examples 5 to 10 Using the polymercaptan compound [2] and Epicoat 828, replacing the 2,4,6-tris (dimethylaminomethyl) phenol used in Examples 1 to 4 with the respective curing accelerations shown in Table 2 When a test was carried out using an agent and a formulation using acetic acid (pot life regulator) and Nicanol Y-50 (manufacturable by Mitsubishi Gas Chemical Company, a formalin condensate of xylene). Table 2 shows the results of evaluating the curability of the obtained cured product, and the pot life, mechanical properties, chemical resistance, and water resistance of the obtained cured product.

[0034]

[Table 2] Note) Versamine K-13: manufactured by Henkel Japan, obtained by adding an epoxy compound to a secondary amino group in a ketimine compound of polyethylene polyamine.

[0035]

The curing agent of the present invention and the composition of the present invention
Not only has excellent high-speed and low-temperature curability than conventional thiol-based curing agents, but also the mechanical properties and water resistance of cured products, which were disadvantages of conventional thiol-based curing agents The thiol-based curing agent can be used at room temperature or at low temperatures, because it greatly improves the physical properties such as chemical resistance. It is suitable for use in required applications. Because of the above effects, the curing agent and the composition of the present invention are useful for the following applications. Binder application: Binder for FRP for seismic reinforcement or joining concrete and steel plate for seismic reinforcement in concrete structure, resin for road pavement material, resin for water-permeable pavement material, etc. Use of coating agent, sealing agent, etc .: concrete repair Agent, waterproofing agent for concrete, sealing agent, potting agent, anticorrosive coating agent, floor coating agent, primer, electrical application (laminated board for printed circuit board, semiconductor encapsulant,
Insulating agent, etc.) Use of molding resin: For molding resin molds, resin models, etc.

Claims (9)

[Claims] 1. An epoxy resin curing agent comprising a mercapto compound (A) represented by the following general formula (1). [In the formula, n is an integer of 5 or more, X is selected from the following (a1) and (a2), and a residue obtained by removing n active hydrogens from a compound (a) having 5 or more active hydrogens. Represent. (A1) Polyglycerin (a2) Compound in which not more than 10 monoepoxy compounds (b) have been added to some or all of the hydroxyl groups of (a1)] 2. The epoxy resin curing agent according to claim 1, wherein (a1) is at least one member selected from glycerin 3 to 10-mers, and n is 5 to 12. 3. The mercaptan equivalent of (A) is 100-1.
The curing agent according to claim 1, wherein the curing agent is 000. 4. An epoxy resin composition comprising the curing agent according to claim 1 and a polyepoxy compound (B). 5. [Mercaptan equivalent of (A)] /
The epoxy resin composition according to claim 4, wherein [Epoxy equivalent of (B)] is 1 / (0.5 to 2). 6. The composition according to claim 4, wherein the curing accelerator contains the following basic substance (C) and / or compound (D) having a phenolic hydroxyl group. Basic substance (C): a basic substance selected from the group consisting of amines (C1), compounds (C2) having a protected amino group which can be converted to a free amino group by hydrolysis, and phosphines (C3). 7. A pot life regulator (E) selected from the group consisting of a compound (E1) having one or more carboxyl groups, a Lewis acid (E2) and an amine complex salt of a Lewis acid (E3). 7. The composition according to any one of 4 to 6. 8. A method for producing a cured epoxy resin, comprising curing the composition according to claim 4. Description: 9. An epoxy resin cured product obtained by subjecting the composition according to claim 4 to a curing reaction.