TW201400463A - Curing agent for anionically curable compounds, curable composition, cured product, novel imidazole-based compound and use of same - Google Patents

Abstract

The present invention provides: a curing agent for anionically curable compounds, which is composed of an imidazole-based compound wherein the 1-position of the imidazole skeleton is protected with a protecting group (A) that can be eliminated at a temperature of 50 DEG C or more; a curable composition which contains the curing agent and an anionically curable compound; a cured product which is obtained by curing the composition; the above-mentioned novel imidazole-based compound; and use of the imidazole-based compound. The present invention provides a novel imidazole-based curing agent which is easily handled and has excellent storage stability and good curability even in cases where the curing agent is used as a one-pack type curing agent. This imidazole-based compound is exemplified by an imidazole-based compound represented by general formula (1). In formula (1), A represents a protecting group that can be eliminated at a temperature of 50 DEG C or more; and each of R1-R3 independently represents a hydrogen atom, an alkyl group having 1-15 carbon atoms or a phenyl group.

Description

Hardener, curable composition, cured product and novel imidazole compound for anion curable compound and use thereof

The present invention relates to a curing agent for an anion curable compound used for curing an anion curable compound such as an epoxide or an episulfide compound, and a curable composition containing the curing agent and the anionic curable compound, and The cured product obtained by curing the composition is a novel imidazole compound which is useful as a curing agent for the anion-curable compound. Further, the present invention relates to the use of the novel imidazole compound as a curing agent for an anionic curing compound.

A curing agent for an anion-curable compound (hereinafter also referred to as an imidazole-based curing agent) composed of an imidazole-based compound is generally used as a curing agent for curing an anion-curable compound such as an epoxide or an episulfide. However, when the liquid imidazole-based curing agent is used as a one-pack type curing agent, there is a problem that the storage stability is remarkably low.

A curing agent using an epoxy-imidazole adduct type is known as a method for improving the storage stability of an imidazole-based curing agent (for example, see Patent Document 1). However, such a hardening agent has problems such as "a complicated mixing step", "a problem of dispersion stability", and "the hardening agent does not reach the details of the base material and causes hardening failure".

On the other hand, as an anion-generating curing agent which simultaneously satisfies both hardenability and storage stability, a ketimine which forms a primary amine as a hardening active material by moisture is known. A latent type hardener (for example, refer to Patent Document 2). However, in terms of the potential mechanism of this hardener, only a primary amine can make it happen, and for an imidazole hardener without a primary amine, this mechanism cannot be applied. Moreover, such hardeners also have the problem of producing outgas when hardened.

Therefore, it has been desired to develop a novel imidazole-based hardener which can have excellent storage stability and good hardenability when used as a one-pack type hardener.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1]: JP-A-2000-1526

[Patent Document 2]: JP-A-2002-249544

An object of the present invention is to provide a novel imidazole hardener which is excellent in storage stability and good hardenability and which is easy to use as a one-part curing agent, and which is hardened by the hardening agent and an anionic hardening compound. A composition: a cured product obtained by curing the composition; and a novel imidazole compound which is useful as a curing agent for the anion-curable compound.

As a result of the ingenuity of the inventors of the present invention, it was found that an imidazole-based curing agent which solves the above problems can be obtained by protecting the position of the imidazole skeleton number 1 with a predetermined protecting group.

That is, the present invention provides a curing agent for an anionic curing compound which is formed by curing an anionic curing compound, and is composed of an imidazole compound, and the position of the imidazole skeleton No. 1 of the imidazole compound is at 50 ° C. Protected by the protecting group A which is detached under the above temperature conditions.

Moreover, the present invention also provides a hardener and an anion hard containing the anion hardening compound. A curable composition of the compound, a cured product obtained by curing the curable composition, and a novel imidazole compound useful as a curing agent for the anion curable compound. Moreover, the present invention also provides the use of the aforementioned novel imidazole compound as a hardener for an anionic hardening compound.

The imidazole-based compound of the present invention is designed such that the C-N bond between the protecting group A and the nitrogen atom of the imidazole skeleton number 1 is broken by heat to form a hardener active material. That is, the imidazole-based compound of the present invention is designed according to the following technical idea: constructing a structure in which a CN bond is easily broken by heat, for example, a group which is apt to form a conjugated double bond by heat as a protective group A, and is bonded to an imidazole Skeleton number 1 on the nitrogen atom.

The curing agent for an anionic curing compound of the present invention has good storage stability, and has higher storage stability than a conventional imidazole curing agent, so that it can be stored as a one-liquid curing agent. Increased stability. Further, the curing agent for an anionic curing compound of the present invention is usually a liquid in a normal state, and requires a dissolution step, and has excellent mixing uniformity, so that it is easy to use.

Figure 1 is a 2-((2,4-dimethoxyphenyl)-(4-benzimidazol-1-yl)-methyl]malonic acid bis(2-isopropyl-5) obtained in Synthesis Example 8. ¹ H-NMR spectrum of -methylhexyl).

The invention is described in detail below, but such descriptions are illustrative of one embodiment of the preferred embodiments. Further, in the present invention, the curing agent for an anionic curing compound includes not only a function as a curing agent but also a function as a curing accelerator (hardening aid).

The hardening agent for an anionic hardening compound of the present invention is an anionic hardening compound hard The hardener used for the chemical conversion is composed of an imidazole compound, and the position of the imidazole skeleton number 1 of the imidazole compound is protected by the protective group A which can be detached at a temperature of 50 ° C or higher.

In the present invention, the protective group A is a protective group which is not desorbed when the temperature is less than 50 ° C under normal pressure conditions, and is desorbed at a temperature of 50 ° C or more; the hardening reaction is started by the detachment of the protective group.

The protecting group A can be detached at a temperature of 50 ° C or higher, preferably 55 ° C or higher, and particularly preferably at a temperature of 60 ° C or higher. Further, from the viewpoint of temperature conditions at the time of curing, the protective group A is preferably detachable at 300 ° C or lower, particularly at a temperature of 295 ° C or lower.

Further, the detachment temperature of the protecting group A can be determined by DSC (Wide Differential Scanning Thermal Analysis); whether the protecting group A has been detached from the position of the imidazole skeleton number 1, by NMR (nuclear magnetic resonance) or GC (gas chromatography) ) Analysis, etc. to confirm.

When the imidazole-based compound is liberated from the protective group A, if it is present alone, it is mostly in a crystalline state; however, in the present invention, after the protective group A is detached, a compound derived from the imidazole-based compound and the liberated protecting group A is formed. In a mixed state, a state in which an imidazole-based compound is dissolved in a compound derived from the protective group A which has been removed is formed. Therefore, in the present invention, it is usually used in a liquid form.

As the imidazole-based compound, an imidazole-based compound represented by the following formula (1) can be exemplified.

In the formula, A is a protecting group which can be detached at a temperature of 50 ° C or higher. R ¹ to R ³ are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or a phenyl group.

The alkyl group having 1 to 15 carbon atoms is chain-like or branched, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a decyl group, an eleven group, and a tenth group. Three bases, fourteen bases, fifteen bases, and the like. In terms of the carbon number of the alkyl group, the carbon number is preferably from 1 to 14, more preferably from 1 to 13. The alkyl group and the phenyl group may have a substituent, and examples thereof include a halogen atom, a hydroxyl group, an alkoxy group, an amine group, a sulfanyl group, an aryl group, a heteroaryl group and the like.

Further, an imidazole compound which is not substituted with a protective group at the position of the imidazole skeleton No. 1 is known to be used as a curing agent for an anion-curable resin such as an epoxy resin; and in the general formula (1), an imidazole moiety other than the protective group A In the present invention, the curing agent for an anionic curing compound of the present invention is not limited to the imidazole compound represented by the formula (1), and the substituents R ¹ to R in the formula (1) are not limited thereto. ³ is a substituent which is used in the imidazole-based curing agent which is known in the art, and may be a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or a phenyl group.

The protecting group A in the present invention is preferably, for example, a group which forms a conjugated double bond by heat, as described above. In order to construct a group which is heated to easily form a conjugated double bond, an effective method is to introduce a pull electron group into the protecting group A. Further, even in the case where only one electron-withdrawing group is introduced into the protective group A, the reaction of the CN bond by thermal cleavage (protective group detachment reaction) proceeds; however, by introducing two or more electron-withdrawing groups, the detachment reaction is carried out. It tends to proceed at a slightly higher temperature, but the storage stability tends to increase.

In the present invention, the molecular weight of the protecting group A is preferably from 100 to 1,000, more preferably from 200 to 900. When the molecular weight is too large, the anion hardening compound tends to be difficult to be crosslinked intensively, so that a cured product having a high glass transition temperature is obtained, and when such an imidazole compound is used as a curing agent, the effect is less likely to be manifested.

As the relevant protecting group A, the protecting group A1 represented by the following formula (2) can be exemplified.

In the formula, R ⁴ to R ⁶ are each independently a hydrogen atom or a pull electron group, and at least two of R ⁴ to R ⁶ are a pull electron group. However, R ⁴ may be an alkyl group having 1 to 15 carbon atoms or an aromatic ring residue having 6 to 18 carbon atoms. In this case, each of R ⁵ and R ⁶ is a electron withdrawing group.

The alkyl group having 1 to 15 carbon atoms is chain-like or branched, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a decyl group, a thirteen group, and a tenth group. Four bases, fifteen bases, etc. In terms of the carbon number of the alkyl group, the carbon number is preferably from 1 to 13, more preferably from 1 to 10. The alkyl group and the aromatic ring residue may have a substituent, and examples thereof include a halogen atom, a hydroxyl group, an alkoxy group, an amine group, a sulfanyl group, an aryl group, and a heteroaryl group as a substituent.

The aromatic ring residue having 6 to 18 carbon atoms is preferably one having electron withdrawing property, for example, a methoxy group, a phenoxy group, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or a dialkylamine group. Aromatic residues are preferred.

As the electron withdrawing group, it is preferred to use a pull electron group which does not form a hydrogen bond. If the electron group contains a functional group that forms a hydrogen bond (for example, a carboxylic acid group, an aldehyde group, a guanamine group, etc.), since a hydrogen bond is formed in or between molecules, it is easily crystallized, and it is difficult to obtain. The tendency of liquid latent hardeners.

Examples of the electron withdrawing group include a nitro group; a cyano group; a functional group containing a halogen atom such as a bromine atom, a chlorine atom, an iodine atom or a fluorine atom; and a functional group having a carbonyl group, for example, a saturated group having a carbon number of 1 to 20 or An ester group of an unsaturated hydrocarbon group, a thioester group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, a sulfhydryl group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, or a saturated or non-carbon number of 1 to 20 carbon atoms a hydrocarbyl group of a saturated hydrocarbyl group, a carbonyloxy group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, a thiocarbonyloxy group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms; containing a sulfonyl group or a sub a functional group of a sulfonyl group, for example, an alkylsulfonyl group having 1 to 20 carbon atoms, an arylsulfonyl group having 6 to 18 carbon atoms, an alkylsulfinyl group having 1 to 20 carbon atoms, and a carbon number of 1 to 20 An alkylsulfonyloxy group, an alkylsulfinyloxy group having 1 to 20 carbon atoms; an aryl group having a functional group, for example, containing a chlorine atom, a bromine atom, an iodine atom, and a fluorine atom An aryl group of 1 to 5 halogen atoms in the group, and an aryl group having 1 to 5 electron withdrawing groups selected from the group consisting of a cyano group and a nitro group.

As the alkyl group in the above alkylsulfonyl group, alkylsulfinyl group, alkylsulfonyloxy group, and alkylsulfinyloxy group, the above chain or branch having a carbon number of 1 to 15 can be exemplified. Alkyl group. Further, examples of the saturated or unsaturated hydrocarbon group having 1 to 15 carbon atoms include the above-mentioned chain-like or branched alkyl group having 1 to 15 carbon atoms and a chain-like or branched alkenyl group having 2 to 15 carbon atoms. Examples of the aryl group in the arylsulfonyl group and the aryl group in the aryl group having a vinyl group include a phenyl group, a benzyl group, a tolyl group, a xylyl group, and a naphthyl group.

The aryl group in the above arylsulfonyl group is a monocyclic chain, a bicyclic ring or a cyclized aryl group having 6 to 18 carbon atoms. For example, a phenyl group, a benzyl group, a tolyl group, a xylyl group, and a naphthyl group are mentioned as an aryl group.

Among them, from the viewpoint of simple synthesis or the availability of a liquid compound, it is preferred to use an ester group, a cyano group, an alkylsulfonyl group or an aryl group as a pull electron group; A cyano group or an aryl group is used as a pull electron group.

Further, as the related protective group A, the protective group A2 represented by the following formula (3) can also be exemplified.

In the formula, R ⁷ is an alkyl group having 1 to 15 carbon atoms or an aromatic ring residue having 6 to 18 carbon atoms; and each of R ⁸ and R ⁹ is an electron-withdrawing group.

The alkyl group having 1 to 15 carbon atoms and the electron withdrawing group can be exemplified by the same as the above. The aromatic ring residue having 6 to 18 carbon atoms may, for example, be a residue of a monocyclic aromatic derivative such as a phenyl group, a benzyl group, a tolyl group or a xylyl group; naphthalene, anthracene, sapotalin, oxime, and ethyl A residue of a polycyclic aromatic derivative such as an alkylene naphthalene or a biphenyl group.

The aromatic ring residue having 6 to 18 carbon atoms is preferably one having electron withdrawing property, for example, a methoxy group, a phenoxy group, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or a dialkylamine group. Aromatic residues are preferred.

Further, as the related protective group A, the protective group A3 represented by the following formula (4) can also be exemplified.

In the formula, R ¹⁰ and R ¹¹ are each independently an alkyl group having 1 to 15 carbon atoms. Examples of the alkyl group having 1 to 15 carbon atoms are the same as those described above.

Further, in the formula, R ¹⁰ and R ¹¹ are preferably an alkyl group having the same carbon number from the viewpoint that the raw material is easily obtained and can be easily and inexpensively synthesized.

Specific examples of the protective group represented by the formula (4) include a dimethyl succinate residue, a di(2-isopropyl-5-methylhexyl) succinate residue, and 2-[ Residue of bis(2-isopropyl-5-methylhexyl) ester of 1-(2,4-dimethoxyphenyl)ethyl]malonate.

The imidazole compound represented by the formula (1) can be produced according to the synthesis conditions well known in the art.

The present invention further provides the novel imidazole compound represented by the above formula (5).

In the formula, R ¹² and R ¹³ are each independently an alkyl group having 1 to 15 carbon atoms; and R ¹⁴ to R ¹⁶ are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or a phenyl group, and an Ar system. An aromatic ring residue having 6 to 18 carbon atoms. Examples of the aromatic ring residue having an alkyl group having 1 to 15 carbon atoms and 6 to 18 carbon atoms are the same as those described above.

From the viewpoints of easy availability of raw materials, easy and inexpensive synthesis, and the like, R ¹² and R ¹³ are preferably an alkyl group having the same carbon number.

Further, R ¹⁴ to R ^{16 are} preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an undecyl group or a phenyl group; and as Ar, a preferred one is a phenyl group or a 4-methoxyphenyl group. , 3-methoxyphenyl, 2-methoxyphenyl, 2,4-dimethoxyphenyl, 2,3-dimethoxyphenyl, 2,5-dimethoxyphenyl, 2,6-di Methoxyphenyl, 3,4-dimethoxyphenyl, 3,5-dimethoxyphenyl, 2,3,4-trimethoxyphenyl, 2,4,5-trimethoxyphenyl, 2,4 ,6-trimethoxyphenyl, 3,4,5-trimethoxyphenyl, 2-hydroxyphenyl, 3-hydroxyphenyl, 4-hydroxyphenyl, 2,3-dihydroxyphenyl, 2,4- Dihydroxyphenyl, 2,5-dihydroxyphenyl, 3,4-dihydroxyphenyl, 3-phenoxyphenyl, 4-phenoxyphenyl, o-tolyl, m-tolyl, p-tolyl, 2 , 3-dimethylphenyl, 2,4-dimethylphenyl, 2,6-dimethylphenyl, 3,4-xylyl, 3,5-dimethylphenyl, 2,4,5-trimethylphenyl, 2 4,6-trimethylphenyl, 4-tris-butylphenyl, 4-dimethylaminephenyl, 4-diethylaminephenyl.

Specific examples of the compound of the formula (5) of the present invention include, for example, 2-[(2,4-dimethoxyphenyl)-(2-methylimidazol-1-yl)-methyl]malonic acid bis (2) -isopropyl-5-methylhexyl)ester, 2-[(2,4-dimethoxyphenyl)-(2-undecyl imidazol-1-yl)-methyl]malonic acid bis (2 -isopropyl-5-methylhexyl)ester, 2-[(2,4-dimethoxyphenyl)-(2-benzimidazol-1-yl)-methyl]malonic acid bis (2-iso Propyl-5-methylhexyl)ester, 2-[(2,4-dimethoxyphenyl)-(4-benzimidazol-1-yl)-methyl]malonic acid bis(2-isopropyl -5-Methylhexyl)ester, 2-[(2,4-dimethoxyphenyl)-imidazol-1-yl-methyl]malonic acid bis(2-isopropyl-5-methylhexyl) Ester, 2-[(2,4-dimethoxyphenyl)-(2-ethyl-4-methylimidazol-1-yl)-methyl]malonic acid bis(2-isopropyl-5-- Ethyl) ester, 2-[(2,4-dimethoxyphenyl)-(4,5-dibenzimidazole-1-yl)-methyl]malonic acid bis(2-isopropyl-5-) Methylhexyl)ester, 2-[(4-benzimidazol-1-yl)-(2,4,6-trimethoxyphenyl)-methyl]malonic acid bis(2-isopropyl-5-- Ethyl) ester, 2-[(4-benzimidazol-1-yl)-(3,4,5-trimethoxyphenyl)-methyl]malonic acid bis(2-isopropyl-5-methyl Hexyl)ester, 2-[(2,4-dimethoxyphenyl)-(4-benzimidazol-1-yl) -methyl]dihexyl malonate, 2-[(2,4-dimethoxyphenyl)-(4-benzimidazol-1-yl)-methyl]malonate dibutyl ester, 2-[ (2,4-Dimethoxyphenyl)-(4-benzimidazol-1-yl)-methyl]malonic acid dipropyl ester, 2-[(4-methoxyphenyl)-(4-benzimidazole -1-yl)-methyl]malonic acid bis(2-isopropyl-5-methylhexyl) ester, 2-[(2-methoxyphenyl)-(4-benzimidazol-1-yl) -methyl] bis(2-isopropyl-5-methylhexyl)malonate, 2-[(4-benzimidazol-1-yl)-p-tolyl-methyl]malonic acid bis (2 -isopropyl-5-methylhexyl)ester, 2-[(4-benzimidazol-1-yl)-o-tolyl-methyl]malonic acid bis(2-isopropyl-5-methylhexyl) Ester, 2-[phenyl-(4-benzimidazol-1-yl)-methyl]malonic acid bis(2-isopropyl-5-methylhexyl) ester.

The imidazole-based compound represented by the above formula can also be produced according to the well-known synthesis conditions.

The curable composition of the present invention contains the curing agent for an anionic curing compound of the present invention and an anion curable compound as a curing target. The anion hardening compound may, for example, be an epoxide or an episulfide compound.

The epoxide group has an average of two or more epoxy groups in one molecule. Typical examples of the epoxide include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol F, and tetramethyl bisphenol AD. Bisphenol type epoxy resin obtained by epoxypropylation of bisphenols such as tetramethylbisphenol S and tetrabromobisphenol A; biphenol, dihydroxynaphthalene, 9,9-bis (4-hydroxyl) Epoxy resin obtained by epoxy propylation of other dihydric phenols such as phenyl) hydrazine; 1,1,1-paraxyl (4-hydroxyphenyl)methane, 4,4-(1-(4-(1) Epoxy resin obtained by epoxy-propylation of -(4-hydroxyphenyl)-1-methylethyl)phenyl)ethylidene bisphenol and other phenols; 1,1,2,2- Epoxy resin obtained by epoxy propylation of hydrazine phenol such as hydrazine (4-hydroxyphenyl)ethane; phenol novolac, cresol novolac, bisphenol A novolac, brominated phenol novolac, bromination A novolac type epoxy resin obtained by epoxy propylation of a bisphenol A novolak or the like; an aliphatic ether type epoxy resin obtained by epoxypropylating a polyhydric alcohol such as glycerol or polyethylene glycol An ether ester type epoxy resin obtained by epoxy-propylating a hydroxycarboxylic acid such as p-hydroxybenzoic acid or β-hydroxynaphthoic acid; An ester type epoxy resin obtained by epoxy-propylating a polycarboxylic acid such as phthalic acid or citric acid; an epoxy propyl compound of an amine compound such as 4,4'-diamine diphenylmethane or m-aminophenol; Or an amine type epoxy resin such as triglycidyl isocyanurate; an alicyclic epoxide such as 3,4-epoxycyclohexylmethyl-3', 4'-epoxycyclohexylcarboxylate. One type or a mixture of two or more types of these epoxides may be used.

Further, the episulfide compound is a compound having a three-membered heterocyclic structure including a sulfur atom. Typical cyclosulfides include, for example, cyclohexyl sulfide, episulfide, 2,2-bis(4-(2,3-cyclosulfoxy)phenyl)propane, and bis(4-( 2,3-Cyclothiopropoxy)phenyl)methane, 1,6-bis(2,3-cyclothiopropoxy)naphthalene, 1,1,1-para-(4-(2,3-ring) Thiopoxy)phenyl)ethane, 1-(2-(2,3-cyclothiopropoxy)phenyl)-1,1-bis-(4-(2,3-cyclothiopropoxy) Phenyl)ethane, 1,1,2,2-indolyl-(4-(2,3-cyclosulfoxy)phenyl)ethane, and the like.

Further, examples thereof include: 2,2-bis(4-(2,3-cyclothiopropoxy)cyclohexyl)propane, bis(4-(2,3-cyclothiopropoxy)cyclohexyl)methane, 4,8-bis(4-(2,3-cyclosulfoxymethyl)-shencyclo [5.2.1.0 ^2.6 ]decane, 3,9-bis(4-(2,3-cyclosulfoxy) Methyl)-Shenmene [5.2.1.0 ^2.6 ]decane, 3,8-bis(4-(2,3-cyclosulfoxymethyl)-shencyclo [5.2.1.0 ^2.6 ]decane, 4 , 8-bis(4-(2,3-cyclothiopropoxy)-shencyclo [5.2.1.0 ^2.6 ]decane, 3,9-bis(4-(2,3-cyclothiopropoxy)- Cyclone [5.2.1.0 ^2.6 ] decane, 3,8-bis(4-(2,3-cyclothiopropoxy)-septene [5.2.1.0 ^2.6 ]decane, 1,1,1-parameter- (4-(2,3-Cyclothiopropoxy)cyclohexyl)ethane, 1-(2-(2,3-cyclothiopropoxy)cyclohexyl)-1,1-bis-(4-( 2,3-Cyclothiopropoxy)cyclohexyl)ethane, 1,1,2,2-indolyl-(4-(2,3-cyclothiopropoxy)cyclohexyl)ethane, etc. One or a mixture of two or more kinds of cyclic sulfides.

Further, the above epoxide and episulfide may be used in combination.

The curable composition of the present invention usually contains 0.1 to 50 parts by weight of the curing agent of the present invention, preferably 0.2 to 45 parts by weight, and particularly preferably 0.3 to 40 parts by weight, based on 100 parts by weight of the anionic curing compound. . When the content of the curing agent is too large, the physical properties of the curing agent tend to be lowered. When the content is too small, the curing reaction tends to be difficult to proceed.

In the curable composition of the present invention, a diluent, a toughening agent, a decane coupling agent, an antifoaming agent, a leveling agent, a reinforcing agent, a filler, a flame retardant, a coloring agent, a pigment, and the like may be added as needed. Various additives such as dyes.

Examples of the diluent include n-butyl epoxypropyl ether, 2-ethylhexyl epoxypropyl ether, phenylepoxypropyl ether, allyl epoxypropyl ether, and styrene oxide. a reactive diluent such as α-pinene oxide, glycidyl methacrylate, 1-vinyl-3,4-epoxycyclohexane, or methyl ethyl ketone, cyclohexanone, toluene, xylene, A non-reactive diluent such as cyclohexane, methanol, isopropanol, acesulfame, ethyl acetate or butyl acetate.

Examples of the toughening agent include ortho-nonanoic acid esters such as dioctyl phthalate or diisopropyl ortho-nonanoate, and polypropylene glycol.

Examples of the decane coupling agent include an imidazole decane coupling agent, an amine decane coupling agent, and an oxime olefin coupling agent.

Examples of the antifoaming agent include an alcohol defoaming agent, a metal soap defoaming agent, a phosphate antifoaming agent, a fatty acid ester defoaming agent, a polyether antifoaming agent, an anthrone defoaming agent, and a fluorine defoaming agent. , mineral oil defoamer, acrylic defoamer, etc.

Examples of the leveling agent include an acrylic leveling agent and an anthrone-based leveling agent.

Examples of the reinforcing agent and the filler include metal oxides such as alumina or magnesia; metal carbonates such as calcium carbonate and magnesium carbonate; diatomaceous earth powder, basic magnesium citrate, calcined clay, and fine powder of cerium oxide. a cerium compound such as molten cerium oxide or crystalline cerium oxide; a powder material such as a metal hydroxide such as aluminum hydroxide; or a fiber such as glass fiber, ceramic fiber, carbon fiber, alumina fiber, cerium carbide fiber, boron fiber or polyester fiber. Material, etc.

Examples of the flame retardant include halides such as tetrabromobisphenol A, tribromophenol, and hexabromobenzene; phosphides such as triphenyl phosphate and polyphosphate; and metal hydrogen such as aluminum hydroxide and magnesium hydroxide. Oxide; lanthanide such as antimony trioxide or antimony pentoxide.

Examples of the above-mentioned coloring agent, pigment, and dye include titanium dioxide, iron ink, molybdenum red, indigo, ultramarine blue, cadmium yellow, cadmium red, antimony trioxide, and red phosphorus.

The curing agent for an anionic curing compound of the present invention may be used singly or in combination with an amine, a polyamine, an anthracene, an acid anhydride, a dicyandiamide, a phosphonium salt, a polythiol, a phenol or a ketimine. The hardener used is used in combination. Further, a curing accelerator (hardening aid) for an anionic curing compound which is known or even general can be used in combination. Further, the curing agent for an anion-curable compound of the present invention can be used in combination with a general curing agent known in the art for catalyzing the promotion of the curing property.

In the method for mixing the curing agent for an anionic curing compound of the present invention with an anionic curing compound, for example, a roller kneader, a kneader, an extruder, or the like is used, and a specified amount is contained. The hardening agent and the curable composition of the anion curable compound are kneaded. Next, by heating the kneaded composition after kneading, a cured product of the anion curable compound can be obtained. In the heating conditions, the type of the anion curable compound, the type of the curing agent, the type of the additive, the blending amount of each component, and the like can be considered, and the heating temperature and the heating time can be appropriately selected.

[Examples]

Hereinafter, the present invention will be more specifically described by way of examples, but the invention is not limited to the examples below, without departing from the spirit thereof.

[Synthesis Example 1: Synthesis of dimethyl 2-(2-butyrazole-1-yl)succinate]

1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) 9.5 g (0.06 mol), acetonitrile 18 ml, 2-butyrazole 17.1 g (0.14 mol) were charged in 100 ml of four The flask was stirred at 25 ° C. Here, 18.0 g (0.12 mol) of dimethyl fumarate was added dropwise, and the mixture was reacted at 25 ° C for 3 hours. After the completion of the reaction, the solvent was removed under reduced pressure, and then extracted with dichloromethane (70 ml) and 50 ml of water. The obtained organic layer was concentrated, and then the obtained concentrate was purified by silica gel column chromatography (ethyl acetate/hexane = 1/1) to give liquid 2-(2- Dimethyl imidazol-1-yl)succinate. The obtained dimethyl 2-(2-butylimid-1-yl)succinate was 13.1 g, and the yield was 39%.

The deprotection reaction of the protecting group of dimethyl 2-(2-butyrazole-1-yl)succinate starts at a temperature of 179 ° C. It can be confirmed by NMR analysis that 2-(2-butyrazole-1 Decomposition of dimethyl succinate in dimethyl succinate. Further, it was confirmed by GC analysis that dimethyl fumarate derived from the protective group A which had been removed was produced.

[Synthesis Example 2: Synthesis of dimethyl 2-(2-undecyl imidazol-1-yl) succinate]

DBU 7.9 g (0.05 mol), acetonitrile 15 ml, and 2-undecylimid 25.5 g (0.11 mol) were placed in a 100 ml four-necked flask and stirred at 25 °C. Here, 15.0 g (0.10 mol) of dimethyl fumarate was added dropwise, and the mixture was reacted at 25 ° C for 3 hours. After the completion of the reaction, the solvent was removed under reduced pressure, and then extracted with dichloromethane (70 ml) and 50 ml of water. The obtained organic layer was concentrated, and then the obtained concentrate was purified by silica gel column chromatography (ethyl acetate/hexane = 3/2) to give liquid 2-(2- Dimethyl decyl imidazol-1-yl)succinate. The obtained dimethyl 2-(2-undecidazol-1-yl)succinate was 12.1 g, and the yield was 32%.

The cleavage reaction of the protecting group of dimethyl 2-(2-undecyl imidazol-1-yl)succinate will start at a temperature of 194 ° C, and it can be confirmed by NMR analysis that 2-(2-Eleven Detachment of dimethyl benzoate in dimethyl imidazol-1-yl)succinate. Further, it was confirmed by GC analysis that dimethyl fumarate derived from the protective group A which had been removed was produced.

[Synthesis Example 3: Synthesis of 2-imidazol-1-ylsuccinic acid bis(2-isopropyl-5-methylhexyl) ester]

DBU 3.8 g (0.03 mol), acetonitrile 20 ml, and imidazole 3.8 g (0.06 mol) were placed in a 100 ml four-necked flask and stirred at 25 °C. Here, 20.0 g (0.05 mol) of bis(2-isopropyl-5-methylhexyl) fumarate was added dropwise, and the mixture was reacted at 25 ° C for 2 hours. After the completion of the reaction, the solvent was removed under reduced pressure, and then extracted with dichloromethane (60 ml) and water 40 ml. The obtained organic layer was concentrated, and then the obtained concentrate was purified by silica gel column chromatography (ethyl acetate /hexane = 2 / 3) to give liquid 2-imidazole-1. - bis(2-isopropyl-5-methylhexyl) succinate. The obtained 2-imidazol-1-ylsuccinic acid bis(2-isopropyl-5-methylhexyl) ester was 9.4 g in a yield of 40%.

The deprotection reaction of the protecting group of 2-imidazol-1-ylsuccinate bis(2-isopropyl-5-methylhexyl) ester starts at a temperature of 259 ° C, and can be confirmed by NMR analysis. Detachment of bis(2-isopropyl-5-methylhexyl) succinate in bis(2-isopropyl-5-methylhexyl) imidazole-1-ylsuccinate.

[Synthesis Example 4: Synthesis of bis(2-isopropyl-5-methylhexyl) 2-(4-benzimidazole-1-yl)succinate]

DBU 1.7 g (0.01 mol), acetonitrile 10 ml, and 4-benzimidazole 3.3 g (0.02 mol) were placed in a 50 ml four-necked flask, and stirred at 25 °C. Here, 9.0 g (0.02 mol) of bis(2-isopropyl-5-methylhexyl) fumarate was added dropwise thereto, and the mixture was reacted at 25 ° C for 30 minutes. After the completion of the reaction, the solvent was removed under reduced pressure, and then extracted with 30 ml of dichloromethane and 20 ml of water. The obtained organic layer was concentrated, and then the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/4) to give liquid 2-(4- Benzimidazol-1-yl)succinic acid bis(2-isopropyl-5-methylhexyl) ester. The obtained bis(2-isopropyl-5-methylhexyl) 2-(4-benzimidazole-1-yl)succinate was 6.9 g in a yield of 56%.

The deprotection reaction of the protecting group of 2-(4-benzimidazole-1-yl)succinic acid bis(2-isopropyl-5-methylhexyl) ester starts at a temperature of 292 ° C and can be obtained by NMR Analysis to confirm bis(2-isopropyl-5-methylhexyl) succinate in bis(2-isopropyl-5-methylhexyl) 2-(4-benzimidazole-1-yl)succinate Ester separation.

[Synthesis Example 5: Synthesis of bis(2-ethylhexyl) 2-(4-benzimidazole-1-yl)succinate]

DBU 2.6 g (0.02 mol), acetonitrile 15 ml, and 4-phenylimidazole 5.0 g (0.04 mol) were placed in a 100 ml four-necked flask and stirred at 25 °C. Here, 11.8 g (0.04 mol) of bis(2-ethylhexyl) fumarate was added dropwise, and the mixture was reacted at 25 ° C for 30 minutes. After the completion of the reaction, the solvent was removed under reduced pressure, and then extracted with dichloromethane (60 ml) and water 40 ml. The obtained organic layer was concentrated, and then the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/4) to give liquid 2-(4- Bis(2-ethylhexyl) ester of benzimidazole-1-yl)succinate. The obtained bis(2-ethylhexyl) 2-(4-benzimidazole-1-yl)succinate was 10.8 g in a yield of 64%.

The deprotection reaction of the protecting group of 2-(4-benzimidazole-1-yl)succinic acid bis(2-ethylhexyl) acrylate starts at a temperature of 287 ° C, and can be confirmed by NMR analysis to confirm 2-( Detachment of bis(2-ethylhexyl) succinate in bis(2-ethylhexyl) 4-benzimidazol-1-yl)succinate.

[Synthesis Example 6: Synthesis of dibutyl 2-(4-benzimidazol-1-yl)succinate]

5.0 g (0.03 mol) of DBU, 15 ml of acetonitrile, and 9.5 g (0.06 mol) of 4-benzimidazole were placed in a 100 ml four-necked flask, and stirred at 25 °C. Here, 15.0 g (0.07 mol) of dibutyl fumarate was added dropwise, and the mixture was reacted at 25 ° C for 30 minutes. After the completion of the reaction, the solvent was removed under reduced pressure, and then extracted with dichloromethane (60 ml) and water 40 ml. The obtained organic layer was concentrated, and then the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/4) to give liquid 2-(4- Dibutyl imidazole-1-yl)succinate. The obtained dibutyl 2-(4-benzimidazole-1-yl)succinate was 12.6 g, and the yield was 51%.

The deprotection reaction of the protecting group of 2-(4-benzimidazol-1-yl)succinate is started at a temperature of 254 ° C, and it can be confirmed by NMR analysis that 2-(4-benzimidazole-1 Separation of dibutyl succinate in di-butyl succinate.

[Synthesis Example 7: Synthesis of 2-(2-ethyl-4-methylimidazol-1-yl)succinic acid bis(2-isopropyl-5-methylhexyl) ester]

1.5 g (0.01 mol) of DBU, 10 ml of acetonitrile, and 2.2 g (0.02 mol) of 2-ethyl-4-methylimidazole were placed in a 50 ml four-necked flask, and stirred at 25 °C. Here, 8.0 g (0.02 mol) of bis(2-isopropyl-5-methylhexyl) fumarate was added dropwise thereto, and the mixture was reacted at 25 ° C for 20 hours. After the end of the reaction, The solvent was removed by pressing, and then extracted with 30 ml of dichloromethane and 20 ml of water. The obtained organic layer was concentrated, and then the obtained concentrate was purified by silica gel column chromatography (ethyl acetate /hexane = 2 / 3) to give liquid 2-(2- Ethyl-4-methylimidazol-1-yl)succinic acid bis(2-isopropyl-5-methylhexyl) ester. The obtained bis(2-isopropyl-5-methylhexyl) 2-(2-ethyl-4-methylimidazol-1-yl)succinate was 5.5 g, and the yield was 54%.

The deprotection reaction of the protecting group of 2-(2-ethyl-4-methylimidazol-1-yl)succinic acid bis(2-isopropyl-5-methylhexyl) succinate starts at 284 ° C The succinic acid bis(2- in 2-(2-ethyl-4-methylimidazol-1-yl)succinic acid bis(2-isopropyl-5-methylhexyl) ester can be confirmed by NMR analysis. Detachment of isopropyl-5-methylhexyl) ester.

[Synthesis Example 8: 2-[(2,4-Dimethoxyphenyl)-(4-benzimidazol-1-yl)-methyl]malonic acid bis(2-isopropyl-5-methylhexyl) ) Synthesis of esters]

2.7 g (0.02 mol) of 4-benzimidazole, 50 ml of THF, and 0.4 g of potassium tertiary butylate (3.6 mmol) were placed in a 200 ml four-necked flask, and stirred at 25 °C. Here, 10.0 g (0.02 mol) of 2-(2,4-dimethoxyphenylene)malonate bis(2-isopropyl-5-methylhexyl) ester was added dropwise, and the reaction was carried out at 25 ° C. 30 minutes. After the completion of the reaction, the solvent was removed under reduced pressure, and then extracted with 100 ml of dichloromethane and 50 ml of water. The obtained organic layer was concentrated, and then the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/4) to obtain a liquid 2-[(2) , 4-Dimethoxyphenyl)-(4-benzimidazol-1-yl)-methyl]malonic acid bis(2-isopropyl-5-methylhexyl) ester. 2-[(2,4-Dimethoxyphenyl)-(4-benzimidazol-1-yl)-methyl]malonic acid bis(2-isopropyl-5-methylhexyl) ester was obtained 5.8 g, yield 45%.

Protected groups of 2-[(2,4-dimethoxyphenyl)-(4-benzimidazole-1-yl)-methyl]malonic acid bis(2-isopropyl-5-methylhexyl) ester The detachment reaction starts at a temperature of 130 ° C, and it can be confirmed by NMR analysis that 2-[(2,4-dimethoxyphenyl)-(4-benzimidazole-1-yl)-methyl] 2-[1-(2,4-Dimethoxyphenyl)ethyl]malonic acid bis(2-isopropyl-) in bis(2-isopropyl-5-methylhexyl) malonate Detachment of 5-methylhexyl) ester.

Further, 2-[(2,4-dimethoxyphenyl)-(4-benzimidazol-1-yl)-methyl]malonic acid bis(2-isopropyl-5-) obtained in Synthesis Example 8 ¹ H-NM spectrogram of methylhexyl) ester (using "Ascend 400" manufactured by Bruker, internal standard substance: tetramethoxysilane, solvent: CDCl ₃ ) as shown in Fig. 1, which belongs to the following.

7.70 ppm (d, 2H, Ar-H)

7.61 ppm(s,1H,N-C(H)=N)

7.17-7.33 ppm(m,5H,Ar-H,N-C(CH)=C)

6.41-6.42 ppm(m, 2H, Ar-H)

6.17 ppm(d,1H,-CH-)

4.60 ppm(d,1H,-CH-)

3.92-3.96 ppm(m,4H,-OCH2-)

3.80 ppm(s,3H,-OCH3)

3.78 ppm(s,3H,-OCH3)

0.72-1.60 ppm (m, 38H, -CH- -CH2-, -CH3)

The determination of the protection group detachment temperature, the confirmation of the detachment of the protecting group, and the analysis of the product after detachment were carried out by the following methods.

[Measurement of detachment temperature]

The hardener synthesized according to the synthesis example was placed in a covered aluminum pan for differential scanning calorimetry (DSC), and the temperature range was measured using a "Diamond DSC" type differential scanning pyrolyzer manufactured by Parkin Elmer. : 30 ° C ~ 350 ° C, heating rate: 10 ° C / min).

[Analysis of the confirmation of the detachment of the protective group and the analysis of the product after the detachment]

The hardener synthesized according to the synthesis example was placed in a round bottom flask (with a piston), and then the round bottom flask was immersed in an oil bath heated to a separation start temperature close to the protective group, and heated for 10 minutes, and then returned. ¹ H-NMR (using "Ascend 400" manufactured by Bruker, internal standard substance: tetramethoxysilane, solvent: CDCl ₃ ) and GC (using "GCMS-GP2010" manufactured by Shimadzu Corporation) at room temperature analysis.

[Examples 1 to 8, Comparative Examples 1 to 6]

Each of the compounds obtained in Synthesis Examples 1 to 8 was used as Examples 1 to 8, and an imidazole compound (Comparative Examples 1 to 4 and 6) and a conventional imidazole of the active materials of each compound obtained in the synthesis example were used. A latent hardener fine powder (trade name: 2MI-AZ, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) (Comparative Example 5) was used as a comparative example, and the following evaluation was performed.

[Storage Stability Test (Applicable Period Test)]

The curing agents of Examples 1 to 8 and Comparative Examples 1 to 6 were added to a bisphenol A type epoxy resin (trade name: jER828, manufactured by Japan Epoxy Resin Co., Ltd.) and mixed to prepare an epoxy resin composition. . Further, the amount of the curing agent added in Examples 1 to 8 was 5 parts by weight based on 100 parts by weight of the bisphenol A type epoxy resin; or the amount of the curing agent added was 30 mmol based on 100 g of the resin. The amount of the hardener added in Comparative Examples 1 to 6 was equivalent to the same amount of the hardener added to the corresponding Examples 1 to 8.

These compositions were placed in a closable 150 ml glass vessel and subjected to a pot life test at 23 °C. The viscosity is measured by a Brookfield viscometer, and the time required to reach the initial viscosity of the just-formed composition to twice the viscosity is taken as the pot life value. The results of the storage stability test are shown in Tables 1 to 5.

[Sclerosing test]

The epoxy resin composition was prepared by using the curing agents of Examples 1 to 8 and Comparative Examples 1 to 6 in the same manner as the storage stability test described above. The curability test was carried out at 150 ° C for these compositions. The sclerosing test was carried out by using 2 g of each composition and measuring the gelation time using a gelation time tester (manufactured by Yasuda Seiki Co., Ltd.). The results of the sclerosing test are shown together in Tables 1 to 5.

From the results shown in Tables 1, 2, 4 and 5, it is understood that Examples 1, 2 and 4 are used as compared with the hardeners of Comparative Examples 1, 2, 4 and 6 which correspond to the active sites of the respective hardeners. In the case of the hardener of 8, the gelation time is somewhat long, but it is the same as the hardening time required for the usual epoxy resin, and can be sufficiently applied to practical use. Further, the hardeners of Examples 1, 2, and 4 to 8 have a longer pot life than the hardeners of Comparative Examples 1, 2, 4, and 6, so that even when used as a one-pack type hardener, Has excellent storage stability.

Further, as is clear from the results shown in Table 3, the storage stability and the hardening performance of the curing agent of Example 3 were superior to those of Comparative Example 3.

Further, as is apparent from the results shown in Table 4, when the hardening agent of the examples 4 to 6 was used as compared with the fine powdery latent imidazole of Comparative Example 5, although the gelation time was somewhat long, it was usual. The hardening time required for the epoxy resin is relatively the same, and can be sufficiently applied to practical use; further, the hardeners of Examples 4 to 6 have the same excellent storage stability as compared with the hardener of Comparative Example 5. . Further, since the curing agent in Comparative Example 5 is in the form of a powder, there is a case where a complicated mixing step is required, or a problem that hardening is not caused by uniform mixing is caused; in contrast, Examples 4 to 6 Since the hardener is liquid, it has excellent mixing uniformity and is easy to use.

From the above, it can be seen that the curing agent for an anionic curing compound of the present invention is used as a one-pack type hard. When used, the agent also has excellent storage stability and good hardenability. Further, since the curing agent for an anion-curable compound of the present invention is usually a liquid in a normal state, it does not require a dissolution step, and the mixing uniformity is also excellent, so that it is easy to use.

Further, the present application is based on Japanese Patent Application No. 2012-108169, filed on May 10, 2012, the content of which is hereby incorporated by reference.

[Industrial use]

The curing agent for an anionic curing compound of the present invention has excellent storage stability and good curability when used as a one-part curing agent, and thus can be used as a curing agent for an anionic curing compound such as an epoxy resin or an episulfide resin. It is particularly useful as a hardener for an anionic hardening compound in the field of electronic materials.

Claims (11)

A curing agent for an anionic curing compound is composed of an imidazole compound, and the position of the imidazole skeleton number 1 of the imidazole compound is protected by a protecting group A which can be detached at a temperature of 50 ° C or higher. The sclerosing agent for an anionic curing compound according to the first aspect of the invention, wherein the imidazole compound is an imidazole compound represented by the following formula (1); (A is a protecting group which can be detached at a temperature of 50 ° C or higher; R ¹ to R ³ are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or a phenyl group). The hardening agent for an anionic hardening compound according to claim 1 or 2, wherein the detachable protecting group A is a protecting group A1 represented by the following formula (2); (R ⁴ to R ⁶ are each independently a hydrogen atom or a electron withdrawing group, and at least two of R ⁴ to R ⁶ are an electron withdrawing group; however, R ⁴ may also be an aromatic ring residue having a carbon number of 6 to 18. Or an alkyl group having 1 to 15 carbon atoms, in which case R ⁵ and R ⁶ each are an electron-donating group). The curing agent for an anionic hardening compound according to claim 1 or 2, wherein the detachable protecting group A is a protecting group A2 represented by the following formula (3); (R ⁷ is an alkyl group having 1 to 15 carbon atoms or an aromatic ring residue having 6 to 18 carbon atoms, and each of R ⁸ and R ⁹ is an electron-donating group). The sclerosing agent for an anionic hardening compound according to claim 1 or 2, wherein the detachable protecting group A is a protecting group A3 represented by the following formula (4); (R ¹⁰ and R ¹¹ are each independently an alkyl group having 1 to 15 carbon atoms). A curing agent for an anionic curing compound according to the first or second aspect of the invention, wherein the anionic curing compound is an epoxide or an episulfide compound. A curable composition containing the curing agent for an anionic curing compound and the anionic curing compound according to Item 1 or Item 2 of the patent application. A cured product obtained by hardening a hardenable composition according to item 7 of the patent application. An application of the imidazole-based compound according to the first or second aspect of the patent application is as a curing agent for an anionic curing compound. An imidazole compound represented by the following formula (5); (R ¹² and R ¹³ are each independently an alkyl group having 1 to 15 carbon atoms; and R ¹⁴ to R ¹⁶ are each independently a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or a phenyl group; 6~18 aromatic ring residue). An application of the imidazole-based compound according to claim 10 of the patent application is as a curing agent for an anionic curing compound.