KR20150018771A - Curing agent for anionically curable compounds, curable composition, cured product, novel imidazole-based compound and use of same - Google Patents

Abstract

A는 50℃ 이상의 온도 조건하에서 이탈 가능한 보호기이다.
R¹∼R³는 각각 독립하여 수소 원자, 탄소수 1∼15의 알킬기, 또는, 페닐기이다.The present invention relates to a curing agent for an anion-curable compound comprising an imidazole-based compound protected at a first position on the imidazole skeleton by a protecting group A which is removable under a temperature condition of 50 ° C or higher, a curable composition comprising the curing agent and an anion- A cured product obtained by curing, and a novel imidazole-based compound and its use. The present invention provides a novel imidazole-based curing agent having excellent storage stability and good curability even when used as a one-pack type curing agent and being easy to handle. As such imidazole-based compounds, imidazole-based compounds represented by the following formula (1) are exemplified.
[Chemical Formula 1]

A is a protecting group capable of leaving 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.

Description

[0001] The present invention relates to a curing agent for an anion-curable compound, a curable composition, a cured product, and a novel imidazole-based compound,

The present invention relates to a curing agent for an anion curing compound for curing an anion curing compound such as an epoxy compound or an episulfide compound, a curing composition containing the curing agent and an anion curing compound, a cured product obtained by curing the composition, To a novel imidazole-based compound useful as a curing agent for a compound. The present invention also relates to the use of the novel imidazole-based compound as a curing agent for an anion-curable compound.

A curing agent for an anion curing compound (hereinafter also referred to as an imidazole curing agent) made of an imidazole-based compound is used as a curing agent for curing an anion curing compound such as an epoxy compound or an episulfide compound. However, when a 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.

It is known to use an epoxy-imidazole radical-type curing agent as a means for improving the storage stability of an imidazole-based curing agent (see, for example, Patent Document 1). However, this curing agent has a problem of "complicated mixing work is required", "there is a problem in dispersion stability", "curing agent does not reach every detail of the substrate, and curing failure occurs".

On the other hand, as an anion generating type curing agent having both a curing property and a storage stability, a ketting agent type latent curing agent is known which generates primary amine as a curing active species by water (see, for example, Patent Document 2). However, this mechanism can not be applied to an imidazole-based curing agent that can generate only primary amine in a mechanism that has potential for the curing agent and does not have a primary amine. This curing agent also has the problem that outgas is generated at the time of curing.

Therefore, development of a novel imidazole-based curing agent having excellent storage stability and good curability even when used as a one-pack type curing agent has been desired.

JP 2000-1526 A JP 2002-249544A

It is an object of the present invention to provide a novel imidazole-based curing agent having excellent storage stability and good curability even when used as a one-pack type curing agent and being easy to handle, a curing composition containing the above-mentioned curing agent and an anion curing compound, And a novel imidazole compound useful as a curing agent for the anion curing compound.

As a result of intensive studies, the present inventors have found that an imidazole-based curing agent that solves the above problems can be obtained by protecting the first position of the imidazole skeleton with a predetermined protecting group.

That is, the present invention provides a curing agent for curing an anion-curable compound, which comprises a curing agent for an anion-curable compound comprising an imidazole-based compound protected at the first position of imidazole skeleton by a protective group A .

The present invention also provides a curable composition containing the curing agent for an anion curable compound and an anion curable 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 . The present invention also provides use of the novel imidazole-based compound as a curing agent for an anion-curable compound.

The imidazole compound of the present invention is designed so that the C-N bond between the protecting group A and the nitrogen atom at the first position of the imidazole skeleton is cleaved by heat to generate a curing agent active species. That is, the imidazole-based compound in the present invention is a structure in which the CN bond is easily cleaved by heat. For example, a group which is prone to form a conjugated double bond by heat is a nitrogen atom at the first position of the imidazole skeleton To be connected to the other.

The curing agent for an anion-curable compound of the present invention has good curability and has higher storage stability than a conventional imidazole-based curing agent, so that storage stability can be improved even when used as a one-pack type curing agent. Further, since the curing agent for an anion curing compound of the present invention is usually a liquid in a state, it does not require a dissolving operation and is excellent in uniform mixing property, so that it is easy to handle.

FIG. 1 is a graph showing the results of a comparison between the yield of 2 - [(2,4-dimethoxyphenyl) - (4-phenylimidazol-1-yl) -methyl] malonate bis H-NMR spectrum of the ^1-hexyl).

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail, but these are only examples of preferred embodiments. Further, in the present invention, the curing agent for an anion curing compound includes not only a function as a curing agent but also a function as a curing accelerator (curing auxiliary).

The curing agent for an anion curing compound of the present invention is a curing agent for curing an anion curing compound, wherein the first position of the imidazole skeleton is composed of an imidazole compound protected with a protecting group A capable of releasing under a temperature condition of 50 ° C or higher. In the present invention, the protecting group A is a protecting group which does not escape at a temperature lower than 50 deg. C under atmospheric pressure but leaves at a temperature of 50 deg. C or higher, and the curing reaction proceeds due to removal of the protecting group.

The protecting group A is a protecting group which can be released at a temperature of 50 ° C or higher, preferably 55 ° C or higher, particularly preferably 60 ° C or higher. From the viewpoint of the temperature condition at the time of curing, the protecting group A is desirably removable under a temperature condition of 300 DEG C or less, particularly 295 DEG C or less.

The removal temperature of the protecting group A can be measured by DSC (Differential Scanning Calorimetry). Whether the protecting group A is deviated from the first position of the imidazole skeleton can be determined by NMR (nuclear magnetic resonance) or GC (gas chromatography) .

The imidazole compound after leaving protective group A is often a crystal, but in the present invention, after elimination of protecting group A, the imidazole compound is in a mixed state with the compound derived from the leaving protecting group A , The imidazole-based compound is dissolved in the compound derived from the leaving protective group A. Therefore, in the present invention, it can usually be handled as a liquid.

Examples of such imidazole-based compounds include imidazole-based compounds represented by the following formula (1).

Wherein A is a protecting group which can be removed under a temperature condition of 50 캜 or more. 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 an alkyl group in a chain form or a branched form and includes, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, A tetradecyl group, and a pentadecyl group. The number of carbon atoms in the alkyl group is preferably 1 to 14 carbon atoms, more preferably 1 to 13 carbon atoms. The alkyl group and the phenyl group may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an alkoxy group, an amino group, a sulfanyl group, an aryl group, and a heteroaryl group.

The imidazole compound in which the first position of the imidazole skeleton is not substituted with a protecting group is already known as a curing agent for an anion curing resin such as an epoxy resin. The imidazole structure portion other than the protecting group A in the formula The curing agent for the anion-curable compound of the present invention is not limited to the imidazole-based compound represented by the general formula (1), and the substituents R ¹ to R ³ in the general formula (1) may be a known imidazole-based curing agent May be a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, and a phenyl group.

In the present invention, as described above, the protecting group A is preferably a group which easily forms a conjugated double bond by heat, for example. It is effective to introduce an electron-attracting group into the protecting group A in order to form a group which is likely to form a conjugated double bond by heat. In addition, even when only one electron-attracting group is introduced into the protecting group A, the reaction (cleavage reaction of the protecting group) to cleave the CN bond by heat proceeds, but the elimination reaction tends to proceed in a slightly higher temperature region , Storage stability tends to be enhanced.

In the present invention, the molecular weight of the protecting group A is preferably 100 to 1000, more preferably 200 to 900. If the molecular weight is too large, it tends to be difficult for the anion-curing compound to be densely crosslinked, so that it is difficult to obtain the effect when the imidazole-based compound is used as a curing agent that a cured product having a high glass transition temperature can be obtained There is a tendency to lose.

Examples of such a protecting group A include a protecting group A1 represented by the following general formula (2).

In the formula, R ⁴ to R ⁶ are each independently a hydrogen atom or an electron-withdrawing group, and at least two of R ⁴ to R ⁶ are electron-attracting groups. 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 that case, R ⁵ and R ⁶ are each an electron-withdrawing group.

The alkyl group having 1 to 15 carbon atoms is an alkyl group in a chain form or a branched form and includes, for example, a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, pentyl group, decyl group, A decyl group, and a pentadecyl group. The number of carbon atoms of the alkyl group is preferably from 1 to 13, more preferably from 1 to 10, carbon atoms. The alkyl group and the aromatic ring residue may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an alkoxy group, an amino group, a sulfanyl group, an aryl group, and a heteroaryl group.

The aromatic ring residue having 6 to 18 carbon atoms is preferably an electron-withdrawing residue, and it is preferable that the aromatic residue has a methoxy group, a phenoxy group, a hydroxyl group, an alkyl group having 1 to 6 carbon atoms, or a dialkylamino group.

As the electron-attracting group, an electron-attracting group which does not form a hydrogen bond is preferable. In electron-donating groups having a functional group (for example, a carboxylic acid group, a formyl group, an amide group, etc.) forming a hydrogen bond, hydrogen bonds are formed in the molecule or between molecules, It tends to be difficult to obtain.

Examples of the electron attractive group include a nitro group, a cyano group, a functional group having a halogen atom such as a bromine atom, a chlorine atom, an oxo atom and a fluorine atom, an ester group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, A thioester group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, an acyl group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, a carbamoyl group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, A carbonyloxy group having a saturated or unsaturated hydrocarbon group, a functional group having a carbonyl group such as a thiocarbonyloxy group having a saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, an alkylsulfonyl group having 6 to 18 carbon atoms An arylsulfonyl group having 1 to 20 carbon atoms, an alkylsulfinyl group having 1 to 20 carbon atoms, an alkylsulfonyloxy group having 1 to 20 carbon atoms, an alkylsulfinyloxy group having 1 to 20 carbon atoms An aryl group containing 1 to 5 halogen atoms selected from the group consisting of a chlorine atom, a bromine atom, an oxo atom and a fluorine atom, a cyano group and a nitro group, And an aryl group having a functional group such as an aryl group containing 5 electron-attracting groups.

Examples of the alkyl group in the above alkylsulfonyl group, alkylsulfinyl group, alkylsulfonyloxy group and alkylsulfinyloxy group include the above-mentioned alkyl group of chain or branched type having 1 to 15 carbon atoms. Examples of the saturated or unsaturated hydrocarbon group having 1 to 15 carbon atoms include the above-described chain-like or branched-chain alkyl group having 1 to 15 carbon atoms, and the branched or branched alkenyl group having 2 to 15 carbon atoms. Examples of the aryl group in the aryl group including an aryl group and an electron-withdrawing group in the arylsulfonyl group include a phenyl group, a benzyl group, a tolyl group, a xylyl group and a naphthyl group.

The aryl group in the arylsulfonyl group is a monocyclic chain, bicyclic or tricyclic aryl group having 6 to 18 carbon atoms. Examples of the aryl group include a phenyl group, a benzyl group, a tolyl group, a xylyl group and a naphthyl group.

Among them, the electron donor group is preferably an ester group, a cyano group, an alkylsulfonyl group or an aryl group in view of obtaining a point that can be easily synthesized or a liquid compound, and particularly preferably an ester group, a cyano group or an aryl group.

As such a protecting group A, for example, a protecting group A2 represented by the following general formula (3) is also exemplified.

Wherein R ⁷ is an alkyl group having 1 to 15 carbon atoms or an aromatic ring residue having 6 to 18 carbon atoms, and R ⁸ and R ⁹ are each an electron-withdrawing group.

The alkyl group having 1 to 15 carbon atoms and the electron-withdrawing group may be the same as those described above. Examples of the aromatic ring residue having 6 to 18 carbon atoms include residues of monocyclic aromatic derivatives such as phenyl group, benzyl group, tolyl group and xylyl group, naphthalene, azene, sapotalin, anthracene, acenaphthylene, And residues of polycyclic aromatic derivatives such as biphenyl.

As the aromatic ring residue having 6 to 18 carbon atoms, it is preferable to have an electron-donating group. For example, it is preferable that the aromatic residue has a methoxy group, phenoxy group, hydroxyl group, alkyl group having 1 to 6 carbon atoms or dialkylamino group.

As such a protecting group A, for example, a protecting group A3 represented by the following general formula (4) is also exemplified.

In the formulas, R ¹⁰ and R ¹¹ each independently represent an alkyl group having 1 to 15 carbon atoms. Examples of the alkyl group having 1 to 15 carbon atoms include those described above.

R ¹⁰ and R ¹¹ in the formulas are preferably alkyl groups having the same carbon number since raw materials are easy to obtain and synthesize and can be inexpensive.

Specific examples of the protecting group represented by the general formula (4) include, for example, dimethyl succinate residue, di (2-isopropyl-5-methylhexanoate) residue, 2- [1- (2,4-dimethoxyphenyl) ethyl] Lauric acid bis (2-isopropyl-5-methylhexyl) residue.

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

The present invention also provides a novel imidazole-based compound represented by the following general formula (5).

Wherein R < ¹² > And R ¹³ is an alkyl group of 1 to 15 carbon atoms independently, R ¹⁴ ~R ¹⁶ is each independently an alkyl group, or a phenyl group of a hydrogen atom, a 1 to 15 carbon atoms, Ar is an aromatic ring residue having a carbon number of 6-18 . Examples of the alkyl group having 1 to 15 carbon atoms and the aromatic ring residue having 6 to 18 carbon atoms include those described above.

R ¹² And R < ¹³ > are preferably alkyl groups having the same number of carbon atoms since the raw materials can be easily obtained and synthesized at low cost.

As R ¹⁴ to R ¹⁶ , a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an undecyl group, and a phenyl group are preferable, and as the Ar, a phenyl group, a 4-methoxy group, 2, 3-dimethoxyphenyl, 2,5-dimethoxyphenyl, 2,6-dimethoxyphenyl, 3,4-dimethoxyphenyl, 3,5-dimethoxyphenyl, A 2-hydroxyphenyl group, a 3-hydroxyphenyl group, a 2-hydroxyphenyl group, a 2-hydroxyphenyl group, a 3,3,3-trimethoxy group, Dihydroxyphenyl, 2,3-dihydroxyphenyl, 2,4-dihydroxyphenyl, 2,5-dihydroxyphenyl, 3,4-dihydroxyphenyl, 3-phenoxyphenyl, 4- A p-tolyl group, a 2,3-xylyl group, a 2,4-xylyl group, a 2,6-xylyl group, a 3,4-xylyl group , A 3,5-xylyl group, a 2,4,5-mesyl group, a 2,4,6-mesyl group, a 4-t-butylphenyl group, a 4-dimethylaminophenyl group and a 4-diethylaminophenyl group.

Specific examples of the compound of formula (5) of the present invention include, for example, 2 - [(2,4-dimethoxyphenyl) -5-methylhexyl), 2 - [(2,4-dimethoxyphenyl) - (2-undecylimidazol- (2-isopropyl-5-methylhexyl), 2 - [(2, 3-dimethoxyphenyl) (4-dimethoxyphenyl) - (4-phenylimidazol-1-yl) -methyl] malonic acid bis (2-ethyl-4-methylimidazol-1-yl) methyl] malonic acid bis (2-isopropyl-5-methylhexyl) -Methyl] malonic acid bis (2-isopropyl-5-methylhexyl), 2 - [(2,4-dimethoxyphenyl) Methyl] malonic acid bis (2-isopropyl-5-methylhexyl), 2 - [(4-phenylimidazol-1-yl) - (2,4,6-trimethoxyphenyl) (2-isopropyl-5-methylhexyl), 2 - [(4-phenylimidazol-1-yl) - (3,4,5-trimethoxyphenyl) 2-isopropyl-5-methylhexyl), 2 - [(2,4-dimethoxyphenyl) - (4-phenylimidazol- (4-phenylimidazol-1-yl) -methyl] malonate was obtained in the same manner as in Example 1, except that 2 - [(2,4-dimethoxyphenyl) (2-isopropyl-5-methylhexyl), 2 - [(4-methoxyphenyl) 2-methoxyphenyl) - (4-phenylimidazol-1-yl) -methyl] malonic acid bis (2-isopropyl-5-methylhexyl) Methyl] malonic acid bis (2-isopropyl-5-methylhexyl), 2 - [(4-phenylimidazol- (2-isopropyl-5-methylhexyl), 2- [phenyl- (4-phenylimidazol-1-yl) -methyl] malonic acid bis have.

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

The curable composition of the present invention comprises a curing agent for an anion curing compound of the present invention and an anion curing compound for curing. As the anion curing compound, for example, an epoxy compound or an episulfide compound can be mentioned.

The epoxy compound has two or more epoxy groups in an average of one molecule. Representative epoxy compounds include bisphenols such as bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol F, tetramethyl bisphenol AD, tetramethyl bisphenol S and tetrabromobisphenol A glycidyl Epoxy resins obtained by glycidylating other divalent phenols such as a bisphenol type epoxy resin, biphenol, dihydroxynaphthalene and 9,9-bis (4-hydroxyphenyl) fluorene, 1,1,1-tris (4-hydroxyphenyl) methane and 4,4- (1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl) ethylidene) bisphenol are glycidylated Epoxy resins, epoxy resins obtained by glycidylating tetrakisphenols such as 1,1,2,2-tetraquis (4-hydroxyphenyl) ethane, phenol novolak, cresol novolak, bisphenol A novolac, Novolak obtained by glycidylation of phenol novolac, An epoxy ester, an aliphatic ether type epoxy resin obtained by glycidylating a polyhydric alcohol such as glycerin or polyethylene glycol, an ether ester type epoxy resin obtained by glycidylating a hydroxycarboxylic acid such as p-oxybenzoic acid or? Ester type epoxy resins obtained by glycidylating a polycarboxylic acid such as a resin, phthalic acid and terephthalic acid, glycidyl compounds of amine compounds such as 4,4-diaminodiphenylmethane and m-aminophenol, and glycidyl derivatives of triglycidyl isocyanurate Amide-type epoxy resins such as 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate and the like, and the like. One or a mixture of two or more of these epoxy compounds may be used.

The episulfide compound is a compound having a complex ternary ring containing a sulfur atom. Representative episulfide compounds include, for example, cyclohexene sulfamide, propylene sulfide, 2,2-bis (4- (2,3-epithiopropoxy) Epithiopropoxy) phenyl) methane, 1,6-di (2,3-epithiopropoxy) naphthalene, 1,1,1-tris (4- Bis (4- (2,3-epithiopropoxy) phenyl) ethane, 1,1,2,2-tetra (4- (2,3-epithiopropoxy) phenyl) ethane, and the like. Further, it is also possible to use 2,2-bis (4- (2,3-epithiopropoxy) cyclohexyl) propane, bis (4- (2,3-epithiopropoxy) cyclohexyl) Tricyclo [5.2.1.0 ^2.6 ] decane, 3,9-bis (4- (2,3-epithiopropoxymethyl) -tricyclo [5.2.1.0 ^2.6 ] decane, 3,8-bis (4- (2,3-epithiopropoxymethyl) -tricyclo [5.2.1.0 ^2.6 ] decane, propoxy) - tricyclo [5.2.1.0 ^2.6] decane, 3,9-bis (4- (2,3-epithio-propoxy) - tricyclo [5.2.1.0 ^2.6] decane, 3,8- bis (4- (2,3- epithiopropoxy) ethane, 1- (2, 3-epithiopropoxy) -tricyclo [5.2.1.0 ^2.6 ] decane, 1,1,1- - (2,3- epithiopropoxy) cyclohexyl) -1,1-bis- (4- (2,3-epithiopropoxy) cyclohexyl) ethane, 1,1,2,2- (4- (2,3-epithiopropoxy) cyclohexyl) ethane, etc. These episulfide compounds Or a mixture of two or more of them may be used.

The epoxy compound and the episulfide compound may be used in combination.

The curable composition of the present invention usually contains 0.1 to 50 parts by weight, preferably 0.2 to 45 parts by weight, particularly preferably 0.3 to 40 parts by weight, of the curing agent of the present invention per 100 parts by weight of the anion curing compound. If the content of the curing agent is too large, the physical properties of the cured product tend to decrease. If the content is too small, the curing reaction tends to be difficult to proceed.

The curable composition of the present invention may contain various additives such as a diluent, a flexibility imparting agent, a silane coupling agent, a defoaming agent, a labeling agent, a reinforcing agent, a filler, a flame retardant, a colorant, a pigment and a dye.

Examples of the diluent include n-butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether allyl glycidyl ether, styrene oxide,? -Pinene oxide, Vinyl-3,4-epoxycyclohexane, or a reactive diluent such as methyl ethyl ketone, cyclohexanone, toluene, xylene, cyclohexane, methanol, isopropanol, methyl cellosolve, Non-reactive diluents, and the like.

Examples of the flexibility-imparting agent include phthalic acid esters such as dioctyl phthalate and diisopropyl phthalate, and polypropylene glycol.

Examples of the silane-based coupling agent include imidazole-based silane coupling agents, amine-based silane coupling agents, and mercapto-based silane coupling agents.

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

Examples of the labeling agent include an acrylic labeling agent and a silicone-based labeling agent.

Examples of the reinforcing agent and filler include metal oxides such as aluminum oxide and magnesium oxide; metal carbonates such as calcium carbonate and magnesium carbonate; diatomaceous earth powder; magnesium alkaline earth silicate; calcined clay; fine powder silica; And metal hydroxides such as aluminum hydroxide, and fibrous materials such as glass fibers, ceramic fibers, carbon fibers, alumina fibers, silicon carbide fibers, boron fibers, and polyester fibers.

Examples of the flame retardant include halogen compounds such as tetrabromobisphenol A, tribromophenol and hexabromobenzene, phosphorus compounds such as triphenyl phosphate and polyphosphate, metal hydroxides such as aluminum hydroxide and magnesium hydroxide, Antimony compounds such as antimony, antimony and antimony pentoxide, and the like.

Examples of the colorants, pigments and dyes include titanium dioxide, iron black, molybdate orange, tungsten blue, cadmium yellow, cadmium red steel, antimony trioxide, red phosphorus and the like. .

The curing agent for an anion curing compound of the present invention may be used alone or in combination with a commonly used curing agent such as amines, polyamines, hydrazines, acid anhydrides, dicyandiamides, onium salts, polythiols, phenols, Or may be used in combination. It is also possible to use a known or general curing accelerator for an anion curing compound (curing aid) in combination. The curing agent for an anion curing compound of the present invention can be used to catalytically accelerate curing performance in combination with the curing agent of the present invention.

As a method for mixing the curing agent for an anion curing compound and an anion curing compound of the present invention, for example, a curing composition containing a predetermined amount of a curing agent and an anion curing compound is kneaded using a roll kneader, a kneader, an extruder or the like . Subsequently, by heating the kneaded curable composition, a cured product of the anion curable compound can be obtained. As the heating conditions, the heating temperature and the heating time can be appropriately selected in consideration of the kind of the anion curing compound, the kind of the curing agent, the kind of the additive, the blending amount of each component, and the like.

(Example)

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

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

9.5 g (0.06 mol) of diazabicyclo-undecene (DBU), 18 ml of acetonitrile and 17.1 g (0.14 mol) of 2-butylimidazole were placed in a flask having a volume of 100 ml and a nitrogen inlet at 25 ° C. Thereto, 18.0 g (0.12 mol) of dimethyl fumarate was added dropwise, and the mixture was reacted at 25 DEG C for 3 hours. After completion of the reaction, the solvent was removed under reduced pressure, followed by extraction with 70 ml of methylene chloride and 50 ml of water. The separated organic layer was concentrated, and the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/1) to obtain liquid 2- (2-butylimidazol-1-yl) succinate dimethyl. The obtained dimethyl 2- (2-butylimidazol-1-yl) succinate was 13.1 g, and the yield was 39%.

2- (2-Butylimidazol-1-yl) succinate dimethyl initiates the elimination reaction of the protecting group under a temperature condition of 179 DEG C, and the succinic acid in 2- (2-butylimidazol- The disappearance of dimethyl could be confirmed by NMR analysis. It was also confirmed by GC analysis that dimethyl fumarate originating from the leaving protective group A was produced.

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

7.9 g (0.05 mol) of DBU, 15 ml of acetonitrile and 25.5 g (0.11 mol) of 2-undecylimidazole were placed in a 100-ml flask having an inlet of four and stirred at 25 ° C. Thereto, 15.0 g (0.10 mol) of dimethyl fumarate was added dropwise, and the mixture was reacted at 25 DEG C for 3 hours. After completion of the reaction, the solvent was removed under reduced pressure, followed by extraction with 70 ml of methylene chloride and 50 ml of water. The collected organic layer was concentrated, and the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 3/2) to obtain liquid 2- (2-undecylimidazol-1-yl) succinic acid dimethyl. The obtained dimethyl 2- (2-undecylimidazol-1-yl) succinate was 12.1 g, and the yield was 32%.

Dimethyl succinate in dimethyl 2- (2-undecylimidazol-1-yl) initiates the elimination reaction of the protecting group under the temperature condition of 194 ° C to give dimethyl 2- (2-undecylimidazol- The separation was confirmed by NMR analysis. It was also confirmed by GC analysis that dimethyl fumarate originating from the leaving protective group A was produced.

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

3.8 g (0.03 mol) of DBU, 20 ml of acetonitrile, and 3.8 g (0.06 mol) of imidazole were added to a flask having a volume of 100 ml and an inlet of 4. The mixture was stirred at 25 캜. Then, 20.0 g (0.05 mol) of bis (2-isopropyl-5-methylhexyl) fumarate was added dropwise and reacted at 25 ° C for 2 hours. After completion of the reaction, the solvent was removed under reduced pressure, and extraction was carried out with 60 ml of methylene chloride and 40 ml of water. The collected organic layer was concentrated and the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 2/3) to obtain a liquid 2-imidazol-1-yl succinic acid bis (2-isopropyl-5-methylhexyl) . The obtained 2-imidazol-1-yl-succinic acid bis (2-isopropyl-5-methylhexyl) was 9.4 g, and the yield was 40%.

The 2-imidazol-1-yl-succinic acid bis (2-isopropyl-5-methylhexyl) initiated the elimination reaction of the protecting group under temperature conditions of 259 ° C, The disappearance of succinic acid bis (2-isopropyl-5-methylhexyl) in 2-isopropyl-5-methylhexyl could be confirmed by NMR analysis.

Synthesis Example 4: Synthesis of 2- (4-phenylimidazol-1-yl) succinic acid bis (2-isopropyl-5-methylhexyl)

1.7 g (0.01 mol) of DBU, 10 ml of acetonitrile and 3.3 g (0.02 mol) of 4-phenylimidazole were placed in a flask having a volume of 50 ml and a nitrogen inlet at 25 ° C. Then, 9.0 g (0.02 mol) of bis (2-isopropyl-5-methylhexyl) fumarate was added dropwise and reacted at 25 ° C for 30 minutes. After completion of the reaction, the solvent was removed under reduced pressure, followed by extraction with 30 ml of methylene chloride and 20 ml of water. The collected organic layer was concentrated, and the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/4) to obtain a liquid 2- (4-phenylimidazol-1-yl) succinic acid bis Propyl-5-methylhexyl). The yield of the obtained 2- (4-phenylimidazol-1-yl) succinic acid bis (2-isopropyl-5-methylhexyl) was 6.9 g and the yield was 56%.

2- (4-Phenylimidazol-1-yl) succinic acid bis (2-isopropyl-5-methylhexyl) initiates the elimination reaction of the protecting group under temperature conditions of 292 캜, 1-yl) succinic acid bis (2-isopropyl-5-methylhexyl) escape of bis (2-isopropyl-5-methylhexyl) succinate was confirmed by NMR analysis.

[Synthesis Example 5: Synthesis of 2- (4-phenylimidazol-1-yl) succinic acid bis (2-ethylhexyl)]

2.6 g (0.02 mol) of DBU, 15 ml of acetonitrile and 5.0 g (0.04 mol) of 4-phenylimidazole were placed in a flask having a volume of 100 ml and a nitrogen inlet at 25 ° C. Thereto, 11.8 g (0.04 mol) of bis (2-ethylhexyl) fumarate was added dropwise and reacted at 25 ° C for 30 minutes. After completion of the reaction, the solvent was removed under reduced pressure, and extraction was carried out with 60 ml of methylene chloride and 40 ml of water. The separated organic layer was concentrated and the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/4) to obtain a liquid 2- (4-phenylimidazol-1-yl) succinic acid bis Hexyl). The yield of the obtained 2- (4-phenylimidazol-1-yl) succinic acid bis (2-ethylhexyl) was 10.8 g and the yield was 64%.

2- (4-Phenylimidazol-1-yl) succinic acid bis (2-ethylhexyl) undergoes a leaving reaction of the protecting group under temperature conditions of 287 ° C to give 2- ) It was confirmed by NMR analysis that escape of succinic acid bis (2-ethylhexyl) in succinic acid bis (2-ethylhexyl).

[Synthesis Example 6: Synthesis of dibutyl 2- (4-phenylimidazol-1-yl) zirconate]

5.0 g (0.03 mol) of DBU, 15 ml of acetonitrile and 9.5 g (0.06 mol) of 4-phenylimidazole were placed in a flask having a volume of 100 ml and a nitrogen inlet at 25 ° C. Thereto, 15.0 g (0.07 mol) of dibutyl fumarate was added dropwise, and the mixture was reacted at 25 DEG C for 30 minutes. After completion of the reaction, the solvent was removed under reduced pressure, and extraction was carried out with 60 ml of methylene chloride and 40 ml of water. The separated organic layer was concentrated, and the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/4) to obtain a liquid dibutyl 2- (4-phenylimidazol-1-yl) succinate. The obtained dibutyl 2- (4-phenylimidazol-1-yl) amic acid was 12.6 g, and the yield was 51%.

The dibutyl 2- (4-phenylimidazol-1-yl) zirconium salt initiated the elimination reaction of the protecting group under temperature conditions of 254 ° C to give dibutyl 2- (4-phenylimidazol-1-yl) NMR spectroscopy.

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

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 added to a flask having a volume of 50 ml and a nitrogen inlet at 25 ° C. 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 completion of the reaction, the solvent was removed under reduced pressure, followed by extraction with 30 ml of methylene chloride and 20 ml of water. The collected organic layer was concentrated, and the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 2/3) to obtain a liquid 2- (2-ethyl-4-methylimidazol-1-yl) succinic acid bis 2-isopropyl-5-methylhexyl). The obtained 2- (2-ethyl-4-methylimidazol-1-yl) succinic acid bis (2-isopropyl-5-methylhexyl) was 5.5 g and the yield was 54%.

(2-ethyl-4-methylimidazol-1-yl) succinic acid bis (2-isopropyl-5-methylhexyl) undergoes a leaving reaction of the protecting group under temperature conditions of 284 ° C to give 2- (2-ethyl-4-methylimidazol-1-yl) succinic acid bis (2-isopropyl-5-methylhexyl) I could confirm.

Synthesis Example 8 Synthesis of 2 - [(2,4-dimethoxyphenyl) - (4-phenylimidazol-1-yl) -methyl] malonic acid bis (2-isopropyl-5-methylhexyl)

2.7 g (0.02 mol) of 4-phenylimidazole, 50 ml of THF and 0.4 g (3.6 mmol) of potassium t-butoxide were added to a flask having a volume of 200 ml and the mixture was stirred at 25 ° C. Then, 10.0 g (0.02 mol) of 2- (2,4-dimethoxybenzylidene) malonic acid bis (2-isopropyl-5-methylhexyl) was added dropwise and reacted at 25 ° C for 30 minutes. After completion of the reaction, the solvent was removed under reduced pressure, followed by extraction with 100 ml of methylene chloride and 50 ml of water. The collected organic layer was concentrated and the obtained concentrate was purified by silica gel column chromatography (ethyl acetate / hexane = 1/4) to obtain a liquid 2 - [(2,4-dimethoxyphenyl) - (4-phenylimidazole -1-yl) -methyl] malonic acid bis (2-isopropyl-5-methylhexyl). 5.8 g of the obtained 2 - [(2,4-dimethoxyphenyl) - (4-phenylimidazol-1-yl) -methyl] malonate bis (2-isopropyl-5-methylhexyl) 45%.

(2-isopropyl-5-methylhexyl) 2 - [(2,4-dimethoxyphenyl) - (4-phenylimidazol- (2-isopropyl-5-methylhexyl) -methyl] malonic acid bis (2-isopropyl-5-methylhexyl) It was confirmed by NMR analysis that the 2- [1- (2,4-dimethoxyphenyl) ethyl] malonic acid bis (2-isopropyl-5-methylhexyl)

(2-isopropyl-5-methyl) -methyl] malonic acid was obtained in the same manner as in Synthesis Example 8, except that 2 - [(2,4-dimethoxyphenyl) ¹ H-NMR spectrum (using "Ascend 400" manufactured by Bruker, internal reference material: tetramethoxysilane, solvent: CDCl ₃ ) of hexyl is shown in FIG. 1, and its attribution is as follows.

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)

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, -CH2-, -CH2-, -CH3)

The measurement of the leaving temperature of the protecting group, the confirmation of whether or not the protecting group was released, and the analysis of the product after the leaving were carried out as follows.

[Measurement of Discharge Temperature]

The curing agent synthesized according to Synthesis Example was placed in an aluminum pan of a lid part and subjected to DSC measurement ("Diamond DSC" manufactured by Parkin Elmer Co., measurement temperature range: 30 to 350 ° C, temperature rise rate: 10 ° C / min).

[Confirmation of whether or not the protecting group is released and analysis of the products after leaving]

After thus a composite curing agent floor is put into a round bottom flask (valve) in a oil bath heated at exit start temperature of the protective group to soak the flask bottom round heated for 10 minutes in the Synthesis Example, it returned to room temperature, ¹ H-NMR (Using "Ascend 400" manufactured by Bruker, internal reference material: tetramethoxysilane, solvent: CDCl ₃ ) and GC (using GCMS-GP2010 manufactured by Shimadzu Seisakusho).

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

Each of the compounds obtained in Synthesis Examples 1 to 8 was used as Examples 1 to 8, and the imidazole compounds (Comparative Examples 1 to 4 and 6) corresponding to the active species of each compound obtained as a comparative example Imidazole-based latent curing agent (trade name: 2MI-AZ, manufactured by Nippon Gohsei Kagaku Kogyo Kabushiki Kaisha) (Comparative Example 5) in the form of a fine powder was used and the following evaluations were carried out.

[Storage stability test (Port life test)]

To the bisphenol A type epoxy resin (trade name: jER828, manufactured by Japan Epoxy Resins Co., Ltd.), the curing agents of Examples 1 to 8 and Comparative Examples 1 to 6 were added and mixed to prepare an epoxy resin composition. The amount of the curing agent added in Examples 1 to 8 was 5 parts by weight per 100 parts by weight of the bisphenol A type epoxy resin or 30 parts by weight with respect to 100 g of the resin and the addition amounts of the curing agents of Comparative Examples 1 to 6 (Moles) of the curing agent of Examples 1 to 8.

These compositions were put into a hermetically sealable 150 ml glass container and subjected to a pot life test at 23 캜. The viscosity was measured with a Brookfield clay system, and the time required for the initial viscosity of the composition immediately after preparation to become twice the viscosity was defined as the pot life value. The results of the storage stability test are shown in Tables 1 to 5.

[Curability test]

An epoxy resin composition was prepared using the curing agents of Examples 1 to 8 and Comparative Examples 1 to 6 in the same manner as in the above storage stability test. These compositions were subjected to a curing test at 150 占 폚. The curability test was conducted by measuring the gelation time using a gel time tester (manufactured by Yasuda Seimitsu Co., Ltd.) using 2 g of each composition. The results of the curability test are shown together in Tables 1-5.

Compound name Amount of hardener Portlife Gel time Example 1 2- (2-butylimidazol-1-yl) succinic acid dimethyl 5.0
Weight portion 18.6 mmol 3 days 5 minutes 5 seconds Comparative Example 1 2-butylimidazole 2.3
Weight portion 18.6 mmol Less than 1 day 1 min 56 sec

Compound name Amount of hardener Portlife Gel time Example 2 2- (2-undecylimidazol-1-yl) succinic acid dimethyl 5.0
Weight portion 13.6 mmol 5 days 13 minutes Comparative Example 2 2-undecylimidazole 3.0
Weight portion 13.6 mmol 2 days 8 minutes 57 seconds

Compound name Amount of hardener Portlife Gel time Example 3 2-imidazol-1-yl-succinic acid bis (2-isopropyl-5-methylhexyl) 5.0
Weight portion 10.8 mmol 2 days 13 minutes 19 seconds Comparative Example 3 Imidazole 0.7
Weight portion 10.8 mmol Less than 1 day 18 minutes 12 seconds

Compound name Amount of hardener Portlife Gel time Example 4 2- (4-phenylimidazol-1-yl) succinic acid bis (2-isopropyl-5-methylhexyl) 16.2
Weight portion 30.0 mmol More than 14 days 11 minutes 56 seconds Example 5 2- (4-phenylimidazol-1-yl) succinic acid bis (2-ethylhexyl) 14.5
Weight portion 30.0 mmol More than 14 days 11 minutes 12 seconds Example 6 2- (4-Phenylimidazol-1-yl) dibutyrate 11.2
Weight portion 30.0 mmol More than 14 days 8 minutes 57 seconds Example 8 (2-isopropyl-5-methylhexyl) -2 - [(2,4-dimethoxyphenyl) 20.3
Weight portion 30.0 mmol 6 days 11 minutes 22 seconds Comparative Example 4 4-phenylimidazole 4.3
Weight portion 30.0 mmol Less than 1 day 4 minutes 5 seconds Comparative Example 5 2,4-diamino-6- [2- (2-methyl-1-imidazolyl) ethyl] -3,4,5-triazine 6.6
Weight portion 30.0 mmol More than 14 days 2 minutes 45 seconds

Compound name Amount of hardener Portlife Gel time Example 7 2- (2-ethyl-4-methylimidazol-1-yl) succinic acid bis (2-isopropyl-5-methylhexyl) 15.2
Weight portion 30.0 mmol 6 days 4 minutes 26 seconds Comparative Example 6 2-ethyl-4-methylimidazole 3.3
Weight portion 30.0 mmol Less than 1 day 1 minute 34 seconds

From the results shown in Tables 1, 2, 4 and 5, when the curing agents of Examples 1, 2 and 4 to 8 were used, the curing agents of Comparative Examples 1, 2, 4 and 6 corresponding to the active sites of the respective curing agents The gelation time is slightly longer than that of the conventional epoxy resin. However, it can be understood that the gelation time can be sufficiently applied to practical use to the same extent as the time required for curing the usual epoxy resin. Further, since the curing agents of Examples 1, 2 and 4 to 8 have an increased pot life value as compared with the curing agents of Comparative Examples 1, 2, 4 and 6, the curing agent having extremely excellent storage stability even when used as a one- .

From the results shown in Table 3, it can be seen that the curing agent of Example 3 is superior to both the curing agent of Comparative Example 3 in terms of storage stability and curing performance.

From the results shown in Table 4, the gelation time was slightly longer than that at the time of using the latent imidazole in the form of fine powder in Comparative Example 5 at the time of using the curing agents of Examples 4 to 6. However, It is understood that the curing agent of Examples 4 to 6 is a curing agent having excellent storage stability equivalent to that of Comparative Example 5. In addition, since Comparative Example 5 is in the form of a powder, troubles such as a troublesome mixing operation, poor uniformity of mixing, and poor curing may occur, whereas the curing agents of Examples 4 to 6 are liquid , It is excellent in uniform mixing property and is easy to handle.

From the above, it can be seen that the curing agent for an anion curing compound of the present invention has excellent storage stability and good curability even when used as a one-pack type curing agent. Further, since the curing agent for an anion curing compound of the present invention is usually a liquid in a state, it does not require a dissolving operation and is excellent in uniform mixing property, so that it is easy to handle.

(Industrial availability)

The curing agent for an anion curing compound of the present invention is useful as a curing agent for an anion curing compound such as an epoxy resin or an episulfide resin because it has excellent storage stability and good curability even when used as a one-pack type curing agent. In particular, it is useful as a curing agent for an anion curing compound in the field of electronic materials.

Claims (11)

A curing agent for an anion curable compound comprising an imidazole-based compound protected at a first position of the imidazole skeleton by a protecting group A which is removable under a temperature condition of 50 캜 or more. The method according to claim 1,
Wherein the imidazole-based compound is an imidazole-based compound represented by the following formula (1).
[Chemical Formula 1]

(A is a protecting group which can be released at a temperature of 50 ° C or higher, and 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 method according to claim 1 or 2,
Wherein the removable protecting group A is a protecting group A1 represented by the following general formula (2).
(2)

(R ⁴ to R ⁶ are each independently a hydrogen atom or an electron-withdrawing group, and R ⁴ to R ⁶ At least two of them are electron gun units. Provided that when R ⁴ is an aromatic ring residue having 6 to 18 carbon atoms or an alkyl group having 1 to 15 carbon atoms, R ⁵ and R ⁶ are each an electron-withdrawing group. The method according to claim 1 or 2,
Wherein the removable protecting group A is a protecting group A2 represented by the following general formula (3).
(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 R ⁸ and R ⁹ are each an electron-withdrawing group) The method according to claim 1 or 2,
Wherein said removable protecting group A is a protecting group A3 represented by the following general formula (4).
[Chemical Formula 4]

(R ¹⁰ and R ¹¹ each independently represent an alkyl group having 1 to 15 carbon atoms) 6. The method according to any one of claims 1 to 5,
Wherein the anion-curable compound is an epoxy compound or an episulfide compound. A curable composition comprising the curing agent for an anion curable compound and an anion curable compound according to any one of claims 1 to 6. A cured product obtained by curing the curable composition of claim 7. Use of the imidazole compound according to claim 1 or 2 as a curing agent for an anion curable compound. An imidazole compound represented by the following formula (5).
[Chemical Formula 5]

(Wherein 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, Ar is a group having 6 to 18 carbon atoms Ring residue.) Use of the imidazole compound according to claim 10 as a curing agent for an anion curing compound.

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