WO2011111723A1 - Resin composition - Google Patents

Abstract

Disclosed is an epoxy resin composition that can be used for an extended period of time, does not burn, and forms a hardened material with excellent adhesive strength. The resin composition is characterized by including an epoxy resin, an onium salt in which the anion is a cyclic borate tetraoxy-anion, and a blocked isocyanate.

Description

Resin composition

The present invention relates to a resin composition that has a long usable time, does not burn, and has excellent adhesive strength.

Epoxy resins have excellent performance in terms of mechanical properties, electrical properties, thermal properties, chemical resistance, adhesion, etc. It is used for purposes. The epoxy resin composition used to be a “two-component” epoxy resin composition in the past, but due to the inconvenience and inconvenience that the main agent and the curing agent must be mixed immediately before use, One-part epoxy resin compositions have been developed.

Patent Document 1 discloses the most typical “one-pack” epoxy resin composition having dicyandiamide, a dihydrazide compound, and an amine adduct compound as a “solid dispersion type curing accelerator”.

In recent years, studies have been made to use onium salts as curing catalysts for thermosetting resins, particularly epoxy resins. Onium salts are ionic organic compounds composed of cations and anions. Patent Document 2 describes that when an onium salt is blended in an epoxy resin, it has a low catalytic activity at low temperatures, but dissociates into anions and cations at high temperatures and becomes a catalyst for a curing reaction.

As an approach to liquefy (lower melting point) onium salts, which are originally high melting point compounds, ionic bonds between anions and cations can be achieved by sterically increasing the anion or cation or delocalizing electrons. The measures such as weakening are taken. In Non-Patent Document 1, an onium salt having a melting point of 100 ° C. or lower is particularly defined as an ionic liquid. An onium salt having a low melting point (hereinafter sometimes referred to as an ionic liquid) is more likely to dissociate than a normal one having a high melting point, and is expected to have high catalytic activity of the thermosetting resin.

For example, Non-Patent Document 2 reports that 1-butyl-3-methylimidazolium tetrafluoroborate, which is an onium salt (ionic liquid) having a low melting point, can be used as a curing agent for an epoxy resin. However, the curing temperature is as high as 190 ° C or higher, and even if 1 to 5 parts by weight is added to 100 parts by weight of the epoxy resin, the curing reaction takes 6.5 to 7 hours, which is very practical. Was not a callable level. Non-Patent Document 3 reports that 1-ethyl-3-methylimidazolium dicyanamide is excellent as a curing catalyst for epoxy resin as a result of studying several ionic liquids. However, since the catalyst activity is weak to completely cure the epoxy resin, it has been necessary to cure at a high temperature for a long time.

In Patent Document 3, an ionic liquid is examined as a curing catalyst for epoxy resin. By using an ionic liquid having a carboxylate (carboxylate ion) as an anion, it has succeeded in obtaining an epoxy resin composition having a long pot life and fast curing. However, since the activity as a catalyst is high and the curing progresses at a stretch by heating, there is a problem that the heat of reaction is accumulated in the thick film curing, and the cured product is observed to be burnt.

On the other hand, blocked isocyanate is a general term for compounds synthesized from active hydrogen compounds and isocyanates, and is a compound in which active hydrogen moieties involved as reaction points in the polymerization reaction are protected from reacting before curing. . This compound decomposes when heated to a high temperature to regenerate the original active hydrogen compound and isocyanate. From this, it is known that a “one-pack type” resin composition can be obtained by blending with a thermosetting resin such as an epoxy resin. For example, Patent Document 4 proposes an epoxy resin composition in which an isocyanate compound and a blocked isocyanate obtained by reacting an imidazole as an active hydrogen compound are blended as a curing agent. However, there is a limit to extending the pot life with molecular design of blocked isocyanate alone. Therefore, there has been a demand for a method for stabilizing the blocked isocyanate and extending the pot life by some method.

Japanese Patent Laid-Open No. 06-211969 JP 11-209583 A WO2009 / 014270 pamphlet JP 59-227925 A

The problem to be solved by the present invention is to provide an epoxy resin composition that has a long usable time and does not cause scorching of the cured product and has excellent adhesion.

As a result of diligent research to solve the above-mentioned problems, the present inventors have found that an onium salt whose anion is a tetraoxycyclic borate anion (hereinafter also simply referred to as “onium salt having a tetraoxycyclic borate anion”). The epoxy resin composition containing a blocked isocyanate has been found to have a longer usable time and to exhibit a mild curing reactivity, thereby completing the present invention.

That is, the present invention has the following features.
[1] A resin composition comprising (A) an epoxy resin, (B) an onium salt whose anion is a tetraoxycyclic borate anion, and (C) a blocked isocyanate.
[2] The resin according to [1] above, wherein the (B) tetraoxy cyclic borate anion is a tetraoxy cyclic borate anion in which at least one molecule of hydroxy acid or dicarboxylic acid is chelate-coordinated to a boron atom. Composition.
[3] (B) The tetraoxy cyclic borate anion is represented by the general formula (I):

(Wherein R ₁ is an organic group, and —O—R ₁ —O— represents a residue of a hydroxy acid or a dicarboxylic acid bonded to a boron atom by releasing two protons.)
Or a bicyclic tetraoxycyclic borate anion represented by the general formula (II):

(Wherein R _1, —O—R ₁ —O— are as defined above, R ₂ is an alkoxy group, and n is 1 or 2.) The resin composition as described in [1] above, wherein
[4] The above [1] to [3], wherein the cation of the onium salt is a secondary or tertiary ammonium cation containing a protonated nitrogen atom or a quaternary phosphonium cation containing a protonated phosphorus atom. ] The resin composition in any one of.
[5] The resin composition as described in any one of [1] to [4] above, wherein the melting point or softening point of the onium salt is 200 ° C. or lower.
[6] The above-mentioned [1] to [5], wherein the blocked isocyanate is a compound obtained by reacting an isocyanate compound with a compound in which an active hydrogen atom is bonded to a nitrogen atom. The resin composition as described.
[7] An adhesive comprising the resin composition according to any one of [1] to [6].
[8] The anion is represented by the general formula (Ia):

(In the formula, —O—R ₃ —O— is a residue of oxalic acid in which two carboxyl groups each release a proton and bonded to a boron atom, or one hydroxyl group and one carboxyl group. Each group releases a proton, indicating a residue of lactic acid or salicylic acid bonded to a boron atom.)
A bicyclic tetraoxycyclic borate anion represented by:
In the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia), when —O—R ₃ —O— is a residue of oxalic acid, the cation is an ammonium cation or a phosphonium cation. Or a sulfonium-based cation,
When —O—R ₃ —O— in the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia) is a residue of lactic acid, the cation is a phosphonium cation or a sulfonium cation. Yes,
When the —O—R ₃ —O— in the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia) is a salicylic acid residue, the cation is a sulfonium cation. An onium salt.
[9] The anion is represented by the general formula (II):

(Wherein R _1, —O—R ₁ —O—, R ₂ , and n are as defined above), a monocyclic tetraoxycyclic borate anion,
An onium salt, wherein the cation is an ammonium cation, a phosphonium cation or a sulfonium cation.

In the resin composition of the present invention, by allowing the onium salt having a tetraoxycyclic borate anion and the blocked isocyanate to coexist, the decomposition of the blocked isocyanate is suppressed during storage or curing, and the usable time is extended. The curing reaction shows mild reactivity, does not cause burning of the cured product, and further reduces the internal stress of the cured product, thereby forming a cured product with excellent adhesion.
Therefore, the resin composition of the present invention is suitably used for structural materials such as prepregs where the resin scoring during curing is a problem, and for applications such as adhesives, adhesive sheets, and sealants in which adhesiveness is particularly important. Furthermore, since it is excellent in preservability, deterioration can be minimized even after a long distribution process.

It is a DSC chart of the resin composition of an Example (Examples 1 and 13) and a comparative example (Comparative Examples 1, 10, and 11). 3 is a DSC chart of resin compositions of Examples (Examples 15 to 19) and Comparative Example (Comparative Example 12).

Hereinafter, the present invention will be described with reference to preferred embodiments thereof.
The resin composition of the present invention contains (A) an epoxy resin, (B) an onium salt having a tetraoxycyclic borate anion, and (C) a blocked isocyanate.

[(A) Epoxy resin]
The epoxy resin used in the present invention is not particularly limited, but those having an average of 2 or more epoxy groups per molecule are preferable. For example, bisphenol A type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, phenol aralkyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy Resin, aromatic glycidylamine type epoxy resin (for example, tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyltoluidine, diglycidylaniline, etc.), alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac Type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, epoxy resin having butadiene structure, dicyclopentadiene Epoxy resin having a structure, diglycidyl etherification product of bisphenol, diglycidyl etherification product of naphthalenediol, glycidyl etherification product of phenols, and diglycidyl etherification product of alcohols, and alkyl-substituted products, halides and the like of these epoxy resins Examples thereof include hydrogenated products. These may use 1 type (s) or 2 or more types.

Among these, the epoxy resin is bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, biphenyl aralkyl type from the viewpoint of maintaining the high heat resistance and low moisture permeability of the resin composition of the present invention. Epoxy resins, phenol aralkyl type epoxy resins, aromatic glycidyl amine type epoxy resins, epoxy resins having a dicyclopentadiene structure are preferred, bisphenol A type epoxy resins and bisphenol F type epoxy resins are more preferred, and bisphenol A type epoxy resins are preferred. Most preferred.

The epoxy resin may be liquid, solid, or both liquid and solid. Here, “liquid” and “solid” are states of the epoxy resin at normal temperature (25 ° C.). From the viewpoint of coatability, workability, and adhesiveness, it is preferable that at least 10% by weight or more of the entire epoxy resin to be used is liquid. As a specific example of such a liquid epoxy resin, “Epicoat 828EL” manufactured by liquid bisphenol A type epoxy resin (Japan Epoxy Resin Co., Ltd. (註: Japan Epoxy Resin Co., Ltd. was merged with Mitsubishi Chemical Co., Ltd. in April 2010)). ”,“ Epicoat 827 ”), liquid bisphenol F type epoxy resin (“ Epicoat 807 ”manufactured by Japan Epoxy Resin Co., Ltd.), naphthalene type bifunctional epoxy resin (“ HP4032 ”manufactured by DIC Corporation,“ HP4032D]), There are liquid bisphenol AF type epoxy resins (“ZXl O59” manufactured by Tohto Kasei Co., Ltd.) and epoxy resins having a hydrogenated structure (“Epicoat YX8000” manufactured by Japan Epoxy Resin Co., Ltd.). Among them, “Epicoat 828EL”, “Epicoat 827” and “Epicoat 807” manufactured by Japan Epoxy Resins Co., Ltd., which have high heat resistance and low viscosity, are preferable, and “Epicoat 828EL” is most preferable. Specific examples of the solid epoxy resin include naphthalene type tetrafunctional epoxy resin (“HP4700” manufactured by DIC Corporation), dicyclopentadiene type polyfunctional epoxy resin (“HP7200” manufactured by DIC Corporation), and naphthol type epoxy resin. (“ESN-475V” manufactured by Toto Kasei Co., Ltd.), epoxy resin having a butadiene structure (“PB-3600” manufactured by Daicel Chemical Industries, Ltd.), epoxy resin having a biphenyl structure (manufactured by Nippon Kayaku Co., Ltd.) NC3000H "," NC3000L "," YX4000 "manufactured by Japan Epoxy Resin Co., Ltd.) and the like.

In the resin composition of the present invention, the content of the epoxy resin is preferably 20% by weight or more, more preferably 40% by weight or more, and further preferably 60% by weight or more with respect to 100% by weight of the nonvolatile content in the resin composition. Preferably, 70% by weight or more is even more preferable, 80% by weight or more is particularly preferable, and 90% by weight or more is particularly preferable. Further, it is preferably 99.0% by weight or less, more preferably 98.5% by weight or less, further preferably 98.0% by weight or less, still more preferably 97.5% by weight or less, and particularly preferably 97.0% by weight or less. Preferably, 96.5% by weight or less is particularly preferable.

[(B) Onium salt having tetraoxycyclic borate anion]
In the present invention, the “onium salt” means an ionic organic compound composed of a cation and an anion. The onium salt used in the present invention is an onium salt whose anion is a tetraoxycyclic borate anion.

In the present invention, “tetraoxy cyclic borate anion” means a tetraoxy cyclic borate anion in which at least one molecule of hydroxy acid or dicarboxylic acid is chelate-coordinated to a boron atom.

Specifically, the general formula (I):

(Wherein R ₁ is an organic group, and —O—R ₁ —O— represents a residue of a hydroxy acid bonded to a boron atom by releasing one proton from each hydroxyl group and one carboxyl group, respectively. Alternatively, two carboxyl groups each release a proton to indicate a dicarboxylic acid residue bonded to a boron atom.)
Or a bicyclic tetraoxycyclic borate anion represented by the general formula (II):

(Wherein R ₁ , —O—R ₁ —O— are as defined above, R ₂ is an alkoxy group, and n is 1 or 2.) Anions can be mentioned.

Particularly, the cyclic borate anion of the formula (II) is generated by adding a trialkyl borate to an onium salt having a hydroxy acid anion or a dicarboxylic acid monoanion. From this, the onium salt having a cyclic borate anion of formula (II) is typically provided as a mixture having a plurality of cations.

The hydroxy acid forming —O—R ₁ —O— in formula (I) and formula (II) is not particularly limited as long as it is an α-hydroxy acid or a β-hydroxy acid. Gluconic acid, citric acid, isocitric acid, alloisocitric acid, lactic acid, phenyllactic acid, hydroxyacetic acid, malic acid, tartaric acid and other α-hydroxy acids, salicylic acid, substituted salicylic acid, 3-hydroxybutyric acid, 3-hydroxyvaleric acid, 3- Examples thereof include β-hydroxy acids such as hydroxycaproic acid. From the viewpoint of high solubility in the epoxy resin, lactic acid, tartaric acid, salicylic acid, hydroxyacetic acid and the like are preferable, and lactic acid, tartaric acid and salicylic acid are particularly preferable.

As the α-hydroxy acid, any of D-form, L-form, racemate and meso form can be used, and there is no particular limitation. Moreover, a hydroxy acid may be used individually by 1 type, or 2 or more types may be mixed and used for it.

Further, the dicarboxylic acid forming —O—R ₁ —O— in the formulas (I) and (II) is not particularly limited as long as it has coordination ability with boron, but 1,2- Benzene dicarboxylic acid, maleic acid, succinic acid, malonic acid, oxalic acid and the like are preferable because they can be expected to have a chelating effect, and oxalic acid is particularly preferable.

In addition, the alkoxy group represented by R ₂ in the formula (II) includes an alkyloxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an aralkyloxy group having 7 to 20 carbon atoms, and a carbon number Is an aminoalkoxy group having 1 to 4 or the like.

Specific examples of the alkyloxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, pentyloxy group, allyloxy group, cyclohexyloxy group, nonyloxy group, dodecyloxy group, hexadecyl group. Oxy group, octadecyloxy group, 2-ethylhexyloxy group, 1,4,7,10-tetraoxaundecyloxy group, 1,4,7,10,13-pentaoxatetradecyl group, 1,4,7 -Trioxaundecyl group and the like. Specific examples of the aryloxy group having 6 to 20 carbon atoms include phenoxy group, naphthyloxy group, o-tolyloxy group, m-tolyloxy group and the like. Specific examples of -20 aralkyloxy groups include benzyloxy group, phenethyloxy group, and 1-naphthylmethyl group. Alkoxy group, 2-naphthylmethyl group, and the like. Specific examples of the aminoalkoxy group having 1 to 4 carbon atoms include 2-aminoethoxy.

The cation that forms an onium salt with the tetraoxycyclic borate anion represented by the formula (I) or the formula (II) is not particularly limited, but an ammonium cation, a phosphonium cation, a sulfonium cation (for example, Triethylsulfonium ion etc.) and the like. From the viewpoint of effectively suppressing the decomposition of the blocked isocyanate, an ammonium cation and a phosphonium cation are preferable.

Examples of ammonium cations include pyrrolium ions (eg, pyrrolium, 2H-pyrrolium, 1-methylpyrrolium, 2,4-dimethylpyrrolium, 2,5-dimethylpyrrolium, N-methylpyrrolium, etc.); oxazolium ions (Eg, oxazolium, isoxazolium, etc.); thiazolium ions (eg, thiazolium, isothiazolium, etc.); imidazolium ions (eg, imidazolium, 2-methylimidazolium, 4-methylimidazolium, 2-methyl-4-ethyl) Imidazolium, 2-ethyl-4-methylimidazolium, 4-methyl-2-phenylimidazolium, 1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-propyl-3-methyl Imidazoli Piperidinium ions, pyrrolidinium ions (for example, pyrrolidinium, 2-methyl-1-pyrrolidinium, pyrrolidinonium, N-methylpyrrolidonium, etc.); pyrazonium ions; guanidinium ions; pyridinium ions; DBU (1 , 8-diazabicyclo [5,4,0] -7-undecene) and DBN (1,5-diazabicyclo [4,3,0] -5-nonene) and other heterocyclic compounds having a partial structure of amidine skeleton Examples include proton adducts. Of these, secondary or tertiary ammonium cations containing protonated nitrogen atoms such as imidazolium ions, proton adducts of heterocyclic compounds having a partial structure of an amidine skeleton, piperidinium cations, and pyrrolidinium cations are preferred. Particularly preferred is a proton adduct of a heterocyclic compound having a partial structure of an imidazolium ion or amidine skeleton.

Examples of the phosphonium-based cation include a quaternary phosphonium cation containing a protonated phosphorus atom, and tetraalkylphosphonium cations such as tetrabutylphosphonium ion and tributylhexylphosphonium ion are particularly preferable.

The onium salt containing the tetraoxy cyclic borate anion represented by general formula (I) and the tetraoxy cyclic borate anion represented by general formula (II) used for the resin composition of the present invention described above Onium salts include novel compounds, and the present invention also provides novel onium salts.

That is, as the first novel onium salt,
The anion is represented by the general formula (Ia):

(In the formula, —O—R ₃ —O— is a residue of oxalic acid in which two carboxyl groups each release a proton and bonded to a boron atom, or one hydroxyl group and one carboxyl group. Each group releases a proton, indicating a residue of lactic acid or salicylic acid bonded to a boron atom.)
A bicyclic tetraoxycyclic borate anion represented by:
When —O—R ₃ —O— in the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia) is an oxalic acid residue, the cation is an ammonium cation, a phosphonium cation or A sulfonium-based cation,
In the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia), when —O—R ₃ —O— is a residue of lactic acid, the cation is a phosphonium cation or a sulfonium cation. ,
When the —O—R ₃ —O— in the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia) is a salicylic acid residue, the cation is a sulfonium cation. Is mentioned.

As a second new onium salt,
The anion is represented by the general formula (II):

(Wherein R _1, —O—R ₁ —O—, R ₂ , and n are as defined above), a monocyclic tetraoxycyclic borate anion,
An onium salt in which the cation is an ammonium cation, a phosphonium cation, or a sulfonium cation.

Typical examples of the onium salt having a tetraoxycyclic borate anion contained in the resin composition of the present invention include the following compounds (1) to (10).
Compound (1): Tetrabutylphosphonium (T-4) -bis [(2S) -2- (hydroxy-kO) propanoate-kO] borate (abbreviation: TBP [(LA) 2B])

Compound (2): Tetrabutylphosphonium (T-4) -bis [ethanedioate-kO, -kO] borate (abbreviation: TBP [(OXA) 2B])

Compound (3): 1,8-diazabicyclo [5,4,0] -7-undecenium (T-4) -bis [ethanedioate-kO, -kO] borate (abbreviation: DBU [(OXA) 2B])

Compound (4): 1,8-diazabicyclo [5,4,0] -7-undecenium (T-4) -bis [(2S) -2- (hydroxy-kO) propanoate-kO] borate (abbreviation: DBU [ (LA) 2B])

Compound (5): 1,8-diazabicyclo [5,4,0] -7-undecenium (T-4) -bis [2- (hydroxy-kO) benzoate-kO] borate (abbreviation: DBU [(SA) 2B ])

Compound (6): 2-methylimidazolium (T-4) -bis [ethanedioate-kO, -kO] borate (abbreviation: 2MZ [(OXA) 2B])

Compound (7): 2-ethyl-4-methylimidazolium (T-4) -bis [(2S) -2- (hydroxy-kO) propanoate-kO] borate (abbreviation: 2E4MZ [(LA) 2B])

Compound (8): Tetrabutylphosphonium (T-4) -bis [2- (hydroxy-kO) benzoate-kO] borate (abbreviation: TBP [(SA) 2B])

Compound (9): Di-1,8-diazabicyclo [5,4,0] -7-undecenium [2,3-dihydroxybutanedioate] diethyl diborate (abbreviation: DBU2TA-TEB mixture)

Compound (10): 2-ethyl-4-methylimidazolium (T-4)-[(2S) -2- (hydroxy-kO) propanoate-kO] diethyl borate (abbreviation: 2E4MZLA-TEB mixture)

As the onium salt having a tetraoxycyclic borate anion used in the present invention, an optimal onium salt can be properly used depending on the application. However, in applications such as prepregs for preventing burns due to heat generation, DBU having a small calorific value is used. [(SA) 2B], DBU [(OXA) 2B], TBP [(SA) 2B], and the like are preferable, and DBU [(SA) 2B] is particularly preferable. For bonding applications, TBP [(SA) 2B], TBP [(LA) 2B], 2E4MZ-TEB mixture and the like having high tensile shear adhesive strength are preferable, and TBP [(SA) 2B] is particularly preferable among them. . In coating applications, 2E4MZ [(LA) 2B] and TBP [(LA) 2B] are preferable, and 2E4MZ [(LA) 2B] is particularly preferable in that the gel time is short and the composition can be cured in a short time. For applications that require a long usable time, such as continuous application of resin, such as film application, adhesion, and coating, TBP [(LA) 2B], TBP [(OXA) 2B], 2MZ [ (OXA) 2B], 2E4MZ-TEB mixture, and the like are preferable, and TBP [(LA) 2B] is particularly preferable because of its good balance with curability.

As a method for synthesizing an onium salt having a tetraoxycyclic borate anion according to the present invention,
(A) By reacting a precursor composed of a desired cation moiety and an anion moiety composed of halogen or a hydroxyl group, a hydroxy acid or a dicarboxylic acid, and boric acid in a solvent, the boron atom is reacted with a hydroxy acid or dicarboxylic acid. Acid ester method in which an anion with a chelate coordination becomes a counter anion,
(B) Hydroxy acid or dicarboxylic acid and boric acid are uniformly dissolved in a solvent capable of dissociating protons to form hydroxy acid or dicarboxylic acid with a boron atom of boric acid to form a chelate structure; A method comprising reacting a precursor composed of a desired cation moiety and a halogen-containing anion moiety for neutralization, and (c) comprising a desired cation moiety and an anion moiety containing a hydroxy acid or dicarboxylic acid. For example, after preparing an onium salt to be prepared, a boric acid triester is added to the onium salt to prepare it by ligand exchange.

An onium salt having a bicyclic tetraoxycyclic borate anion of formula (I) is obtained by the above methods (a) and (b), and a monocyclic tetravalent compound of formula (II) is obtained by the above method (c). An onium salt having an oxycyclic borate anion is obtained.

Of the three alcohol residues (alkoxy groups) of the boric acid triester used in the method of (c) above, two alcohol residues (alkoxy groups) are monocyclic tetraoxy of formula (2) Ligand exchange with a moiety represented by R ₂ in the cyclic borate anion. Therefore, as the boric acid triester used in the method (c), boric acid triesters whose alcohol residues correspond to the alkoxy groups mentioned as specific examples of R ₂ are used. Trimethyl borate, triethyl borate, tri-n-propyl borate, triisopropyl borate, tri-n-butyl borate, tripentyl borate, triallyl borate, trihexyl borate, tricyclohexyl borate, trioctyl borate, trinonyl borate, Tridodecyl borate, trihexadecyl borate, trioctadecyl borate, tribenzyl borate, triphenyl borate, tri-O-tolyl borate, tri-m-tolyl borate, triethanolamine borate and the like are used.

As the solvent used in the above production methods (a) to (c), polar solvents such as alcohol solvents, ketone solvents, aprotic polar solvents, water, etc. are preferable. Uniform mixed solvents of other organic solvents can also be used. In addition, when the melting points of the raw material and the product are low, it is possible to carry out the reaction without solvent.

Specific examples of these solvents include alcohol solvents such as methanol, ethanol, propanol, isopropanol, butanol, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-butoxyethanol, ethylene glycol. , Propylene glycol, glycerin and the like. Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl propyl ketone, diethyl ketone, butyl methyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of aprotic polar solvents include acetonitrile, dioxane, trioxane, methylfuran, tetrahydrofuran, tetrahydropyran, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, Examples include hexamethylphosphoamide and sulfolane. In the present invention, these solvents can be particularly preferably used, but are not limited thereto.

The reaction conditions for obtaining the onium salt by the above methods (a) to (c) vary depending on the conditions such as the raw material, solvent, and charged amount. For example, in the case of the method (a) or (b), the ratio x of hydroxy acid or dicarboxylic acid to boric acid is in the range of 1.5 <x <2.5 in terms of molar ratio (hydroxy acid or dicarboxylic acid / boric acid). And the ratio y of the precursor containing a cation moiety to boric acid or boric acid triester is in the range of 0.5 <y <1.5 in terms of molar ratio (precursor / boric acid or boric acid triester). It is preferable to charge. In the case of the method (c), the ratio z of boric acid triester to onium salt is 0.5 <z <1.5 in terms of molar ratio (boric acid triester / onium salt).

In the case of using a solvent, it is preferable that the solid content concentration with respect to the solvent is charged in the range of 5 to 50 wt% and the reaction is performed at a temperature in the range of about 0 to 100 ° C. for about 1 to 8 hours. In the case where water is produced, it is preferable to perform a dehydration operation during or after the reaction, and the dehydration operation is preferably, for example, dehydration distillation or vacuum concentration.

The method for recovering the produced onium salt from the reaction solution varies depending on the melting point of the produced onium salt. Examples thereof include, but are not particularly limited to, recovery as an oily substance by concentration, recovery as a solid substance by drying under reduced pressure, and recovery by crystallization by cooling the reaction solution below the melting point. The yield can be further increased by adding an alcohol-based poor solvent such as water or 2-propanol to the reaction solution for precipitation. If the collected onium salt has a problem of the presence of a small amount of impurities depending on the application, a product having a desired purity can be prepared by washing with an organic solvent or pure water.

In the present invention, the onium salt having a tetraoxycyclic borate anion preferably has a melting point or softening point of 200 ° C. or lower, more preferably 180 ° C. or lower, still more preferably 150 ° C. or lower, and still more. Preferably it is 100 degrees C or less, Most preferably, it is 50 degrees C or less. Those having such a low melting point or low softening point have a more prominent effect of inhibiting the decomposition of the blocked isocyanate during storage or curing of the resin composition, extending the pot life of the resin composition, and scoring the cured product. It works better by prevention.
The softening point of an onium salt having a tetraoxycyclic borate anion refers to a temperature at which a solid state is lost by heating when onium salts having different melting points are mixed.

In the resin composition of the present invention, the content of the onium salt having a tetraoxycyclic borate anion in the resin composition is (A) component 100 in the resin composition from the viewpoint of obtaining a cured product having a sufficiently high adhesive strength. 0.5 weight part or more is preferable with respect to a weight part, 1 weight part or more is more preferable, and 1.5 weight part or more is still more preferable. On the other hand, from the viewpoint of preventing rapid curing, the upper limit is preferably 10 parts by weight or less, more preferably 8 parts by weight or less, and still more preferably 6 parts by weight or less.

The content of the onium salt having a tetraoxycyclic borate anion is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, based on 100% by weight of the nonvolatile content in the resin composition. 0.5% by weight or more is more preferable, 1.0% by weight or more is further more preferable, 1.5% by weight or more is particularly preferable, and 2.9% by weight or more is particularly preferable. Further, it is preferably 9.0% by weight or less, more preferably 8.0% by weight or less, still more preferably 7.0% by weight or less, still more preferably 6.0% by weight or less, and particularly preferably 5.0% by weight or less. preferable.

[(C) Block isocyanate]
The blocked isocyanate used in the resin composition of the present invention is a reaction between an isocyanate group (—NCO) of an isocyanate compound having at least one isocyanate group (—NCO) in the molecule and an active hydrogen atom of the active hydrogen compound. A compound having at least one binding site represented by —NH—CO—X— (wherein X represents an atom to which an active hydrogen atom of the active hydrogen compound was bonded) in the molecule. Yes, it may be either a low molecular compound or a high molecular compound.

The active hydrogen compound is not particularly limited as long as it has an active hydrogen atom. For example, a compound in which an active hydrogen atom is bonded to an oxygen atom, a compound in which an active hydrogen atom is bonded to a nitrogen atom, or a sulfur atom. The compound etc. which the active hydrogen atom has couple | bonded can be mentioned, Preferably they are the compound which the active hydrogen atom has couple | bonded with the oxygen atom, and the compound which the active hydrogen atom has couple | bonded with the nitrogen atom.

Compounds having an active hydrogen atom bonded to an oxygen atom (that is, an active hydrogen compound in which X in the above formula is an oxygen atom) include alcohols having 1 to 20 carbon atoms (aliphatic, aromatic or alicyclic) Monohydric or dihydric or higher alcohols), compounds having a phenolic hydroxyl group, polyol resins, and the like, preferably compounds having a phenolic hydroxyl group, and polyol resins. Examples of the compound having a phenolic hydroxyl group include a phenol resin and a phenol novolac resin. Examples of the polyol resin include acrylic polyol resin, polyester polyol resin, polyurethane polyol resin, polyvinyl butyral resin, cellulose acetate propionate, and cellulose acetate butyrate. Rate and the like. Among these, from the viewpoint of the solubility of the obtained blocked isocyanate in the epoxy resin, a phenol novolac resin and a polyol resin having a molecular weight of 20,000 or less are particularly preferable. In addition, although the minimum of the said molecular weight is not specifically limited, 80 or more is suitable.

Examples of the compound in which an active hydrogen atom is bonded to a nitrogen atom (that is, an active hydrogen compound in which X in the above formula is a nitrogen atom) include N-substituted amines, preferably having 1 to 4 carbon atoms. Examples include lower dialkylamines, alicyclic amines having 4 to 20 carbon atoms, and imidazoles. Preferred lower dialkylamines include dimethylamine, diethylamine, di-n-propylamine and the like. Preferred examples of the alicyclic amines include piperidine, pyrrolidine, morpholine, and lower alkyl substituted products thereof. Examples of imidazoles remain active hydrogen groups such as imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, etc. An imidazole compound is mentioned. Among these, dimethylamine, diethylamine, di-n-propylamine, piperidine, pyrrolidine, morpholine, 2-ethyl-4-methylimidazole, 2-ethyldiamine, diethylamine, di-n-propylamine, piperidine, morpholine, 2-ethyl-4-methylimidazole from the viewpoint of solubility in an epoxy resin when the obtained blocked isocyanate is obtained. Phenyl imidazole, 2-undecyl imidazole and the like are preferable. From the viewpoint of stability when a blocked isocyanate is used, dimethylamine, diethylamine, di-n-propylamine, piperidine, pyrrolidine, morpholine, 2-ethyl-4-methylimidazole Is particularly preferred, and most preferred is dimethylamine.

Compounds having an active hydrogen atom bonded to a sulfur atom (that is, an active hydrogen compound in which X in the above formula is a sulfur atom) include thiols having 1 to 10 carbon atoms and aromatic mercapto having 1 to 10 carbon atoms. Examples thereof include compounds.

The isocyanate compound is not particularly limited, but monoisocyanates such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, isobutyl isocyanate, hexyl isocyanate, phenyl isocyanate, etc .; methane diisocyanate, 1,2-ethylene diisocyanate 1,3-trimethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,8-octamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene Alkylene diisocyanates such as diisocyanates; aliphatic diisocyanates such as 3,3′-diisocyanate dipropyl ether and similar alkylene diisocyanates Cycloaliphatic diisocyanates such as cyclopentane diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate; 2,4-tolylene diisocyanate (toluene-2,4-diisocyanate), phenylene diisocyanate, xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate , Aromatic diisocyanates such as diphenyl ether diisocyanate, naphthalene diisocyanate, full orange isocyanate, 4,4′-biphenyl diisocyanate and the like, and prepolymers that are both terminal isocyanates. Among these, alicyclic diisocyanates and aromatic diisocyanates are preferable from the viewpoints of solubility and reactivity.

In the present invention, the blocked isocyanate is preferably a compound obtained by reacting an isocyanate compound with a compound in which an active hydrogen atom is bonded to a nitrogen atom, particularly preferably tolylene diisocyanate and dimethylamine. An aromatic dimethylurea compound represented by the following formula obtained by reacting

Block isocyanate can be obtained by a known method, and can be produced by either a solvent-free system or a solvent system. In the case of a solvent system, an aprotic solvent inert to the isocyanate group, such as toluene, hexane, chloroform, methylene chloride, tetrahydrofuran, acetone, methyl ethyl ketone, γ-butyrolactone, N-methylpyrrolidone, dimethylacetamide, etc. is used. Is preferred. The amount of the active hydrogen compound used is preferably from 0.1 to 3 equivalents, more preferably from 0.2 to 2 equivalents in terms of active hydrogen functional group, with respect to 1 equivalent of isocyanate group in the isocyanate compound. Unreacted isocyanate compound and active hydrogen compound may be removed by a method such as filtration and recrystallization after the reaction is completed. In addition, when the reaction is completed, there is no particular problem even if it is added to the resin without purification.

In the reaction of an isocyanate compound and an active hydrogen compound when synthesizing a blocked isocyanate, a reaction catalyst can be used for the purpose of promoting the reaction. As the reaction catalyst, those having basicity are generally preferred, specifically, tetraalkylammonium hydroxide such as tetramethylammonium, organic weak acid salts such as acetic acid, metal salts such as tin, zinc and lead of alkylcarboxylic acid. And metal alcoholates such as sodium and potassium, aminosilyl group-containing compounds such as hexamethyldisilazane, and phosphorus compounds such as tributylphosphine. These may use 1 type (s) or 2 or more types.

The amount of catalyst is usually preferably 10 to 10,000 ppm, more preferably 20 to 5000 ppm based on the total weight of the isocyanate compound and the active hydrogen compound.

In addition, since such a reaction catalyst may deteriorate the storage stability and cured product characteristics of the resin composition, the catalyst may be neutralized with an acidic compound or the like. Examples of acidic compounds in this case include inorganic acids such as hydrochloric acid and phosphoric acid, sulfonic acids such as p-toluenesulfonic acid and p-toluenesulfonic acid methyl ester, and derivatives thereof, and ethyl phosphate. These may use 1 type (s) or 2 or more types. This neutralization reaction is preferably performed in the range of −20 ° C. to 150 ° C., more preferably 0 ° C. to 100 ° C. If it exceeds 150 ° C, side reactions may occur, and if it is less than -20 ° C, the reaction tends to be slow.

In the resin composition of the present invention, the content of the blocked isocyanate in the resin composition is from the viewpoint of obtaining a cured product having a sufficiently high adhesive strength to 0. 0 parts by weight relative to 100 parts by weight of the component (A) in the resin composition. 5 parts by weight or more is preferable, 1 part by weight or more is more preferable, and 1.5 parts by weight or more is still more preferable. On the other hand, from the viewpoint of preventing rapid curing, the upper limit is preferably 10 parts by weight or less, more preferably 8 parts by weight or less, still more preferably 6 parts by weight or less, and particularly preferably 3 parts by weight or less.

Further, the content of the blocked isocyanate is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, and further preferably 0.5% by weight or more with respect to 100% by weight of the nonvolatile content in the resin composition. Preferably, 1.0% by weight or more is even more preferable, 1.5% by weight or more is particularly preferable, and 1.9% by weight or more is particularly preferable. Further, it is preferably 9.0% by weight or less, more preferably 8.0% by weight or less, further preferably 7.0% by weight or less, still more preferably 6.0% by weight or less, and particularly preferably 5.0% by weight or less. Preferably, 3.0 weight% or less is particularly preferable.

As described in the background art section, conventionally, attempts have been made to use a urea compound (block isocyanate) obtained by reacting an isocyanate compound with imidazoles as a curing agent for an epoxy resin. In general, the gelation time (gel time) required for curing tends to be relatively long.

On the other hand, the resin composition of the present invention has a longer usable time and suppresses a rapid reaction by the presence of an onium salt having a blocked isocyanate and a tetraoxycyclic borate anion in the resin composition. Therefore, it is possible to form a cured product that does not burn and exhibits good adhesion.

Accordingly, in the resin composition of the present invention, the amount of (B) the onium salt having a tetraoxycyclic borate anion is determined for the purpose of effectively inhibiting the decomposition of the blocked isocyanate during storage or curing of the resin composition. It is preferably 0.3 or more, more preferably 0.5 or more in terms of functional group equivalent molar ratio to the blocked isocyanate. On the other hand, if the addition amount is too large, the physical properties of the cured product tend to be lowered. Therefore, the upper limit is preferably 5 or less, and more preferably 2 or less.

Also, (B) an onium salt having a tetraoxycyclic borate anion and (C) a blocked isocyanate can be blended separately in the resin composition. Moreover, it can also mix | blend with an epoxy resin after mixing beforehand. When mixed in advance with an epoxy resin, the decomposition of the blocked isocyanate in the resin composition is more effectively suppressed.

In the resin composition of the present invention, an appropriate amount of a known additive in an adhesive such as an inorganic filler, rubber particles, a thermoplastic resin, a coupling agent, or a sealing agent can be blended as necessary.

The inorganic filler is blended for the purpose of improving moisture permeability and adhesion of the cured product. Specifically, silica, alumina, barium sulfate, talc, clay, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate , Magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate and the like, and one kind or two or more kinds are used in combination. When the inorganic filler is used, the amount of the inorganic filler is suitably about 5 to 60% by weight with respect to 100% by weight of the nonvolatile content in the resin composition.

Rubber particles are blended for the purpose of improving the mechanical strength and stress relaxation of the cured product. Specific examples include core-shell type rubber particles, cross-linked acrylonitrile butadiene rubber particles, cross-linked styrene butadiene rubber particles, acrylic rubber particles, and the like, and one or more types are used in combination. The core-shell type rubber particles are rubber particles having a core layer and a shell layer. For example, the outer shell layer is a glassy polymer and the inner core layer is a rubbery polymer. Examples include a three-layer structure in which the shell layer is a glassy polymer, the intermediate layer is a rubbery polymer, and the core layer is a glassy polymer. When rubber particles are used, the blending amount of the rubber particles is suitably about 5 to 20% by weight with respect to 100% by weight of the nonvolatile content in the resin composition. A rubber particle-containing epoxy resin in which rubber particles are contained in an epoxy resin is commercially available (Kaneka Corporation “MX-120”, “MX-130”, etc.), and such a rubber particle-containing epoxy resin. May be used.

Thermoplastic resin is blended for the purpose of imparting flexibility to the cured product. Specific examples include phenoxy resin, polyvinyl acetal resin, polyimide resin, polyamideimide resin, polyethersulfone resin, polysulfone resin, and the like, and one or more types are used in combination. Among them, the phenoxy resin is preferable because it has good compatibility with the “epoxy resin” and has little influence on the adhesiveness of the cured product, and the phenoxy resin is a bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol. Those having one or more skeletons selected from acetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton and trimethylcyclohexane skeleton are preferred. Specific examples of the phenoxy resin include 1256, 4250 (bisphenol A skeleton-containing phenoxy resin) manufactured by Japan Epoxy Resin Co., Ltd., YX8100 (bisphenol S skeleton-containing phenoxy resin) manufactured by Japan Epoxy Resin Co., Ltd., Japan Epoxy Resin Co., Ltd. YX6954 (bisphenolacetophenone skeleton-containing phenoxy resin), Union Carbide PKHH (weight average molecular weight (Mw) 42600, number average molecular weight (Mn) 11200), Toto Kasei Co., Ltd. FX280, FX293, Japan Epoxy Resin Co., Ltd. YL7553BH30, YL6794, YL7213, YL7290, YL7482 etc. are mentioned. When the thermoplastic resin is used, the content of the thermoplastic resin is suitably about 1 to 50% by weight with respect to 100% by weight of the nonvolatile content in the resin composition.

The coupling agent is blended for the purpose of improving adhesiveness (adhesion with the adherend) and improving moisture resistance of the cured product. Examples of such coupling agents include titanium coupling agents, aluminum coupling agents, silane coupling agents, and the like. Among these, a silane coupling agent is preferable. A coupling agent can be used 1 type or in combination of 2 or more types. When a coupling agent is used, the content of the coupling agent is suitably about 0.5 to 10% by weight with respect to 100% by weight of the nonvolatile content in the resin composition.

The resin composition of the present invention may further contain various resin additives other than the components described above. Examples of such resin additives include organic fillers such as silicone resin powder, nylon resin powder, and fluororesin powder, thickeners such as olben and benton, silicone-based, fluorine-based, and polymer-based antifoaming agents. Etc.

The resin composition of the present invention has low-temperature curability and is generally not more than 60 minutes, preferably not more than 30 minutes in a low temperature range of 120 ° C. or less, preferably 100 ° C. or less, more preferably 80 ° C. or less. More preferably, it can be cured in a short time of 15 minutes or less. The lower limit of the curing temperature and the curing time is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and more preferably 60 ° C. or higher, from the viewpoint of ensuring sufficiently satisfactory adhesion of the cured product. Is preferably 5 minutes or longer.

The method for preparing the resin composition of the present invention is not particularly limited, and examples thereof include a method of mixing compounding components using a known rotary mixer or the like.

The resin composition of the present invention is suitable for use in structural materials such as prepregs where resin scoring during curing is a problem, and adhesives, adhesive sheets, sealants and the like in which adhesiveness is particularly important. can do.

When used for an adhesive sheet, it is used as a sheet of the resin composition of the present invention alone or as an adhesive sheet with a support in which a layer (adhesive layer) of the resin composition of the present invention is formed on a support. be able to.

The adhesive sheet is prepared by a method known to those skilled in the art, for example, by preparing a varnish in which the resin composition is dissolved in an appropriate organic solvent, applying the varnish on the support, and further heating or blowing hot air to the organic solvent. It can manufacture by making it dry and forming a resin composition layer. There are no particular restrictions on the drying conditions, but a temperature of 40 to 130 ° C. and about 1 to 60 minutes are suitable.

Examples of the support include polyolefins such as polyethylene, polypropylene and polyvinyl chloride, polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”), polyesters such as polyethylene naphthalate, plastic films such as polycarbonate and polyimide. The support may be subjected to a release treatment in addition to a mat treatment and a corona treatment. Examples of the release treatment include a release treatment with a release agent such as a silicone resin release agent, an alkyd resin release agent, and a fluororesin release agent. When the adhesive sheet is a sheet made of a resin composition alone, an adhesive sheet can be obtained by forming the resin composition layer on a release-treated support and then peeling the resin composition layer.

The thickness of the adhesive sheet (the thickness of the resin composition layer after drying) is preferably about 5 to 200 μm. Further, the thickness of the support in the adhesive sheet with the support is not particularly limited, but is preferably about 10 to 150 μm from the viewpoint of the handleability of the adhesive sheet.

For example, the organic EL element can be sealed by transferring and curing the adhesive sheet on the substrate on which the organic EL element is formed, and the adhesive sheet in the present invention is used as a sealing agent. You can also.

When the resin composition of the present invention is used for a prepreg, a composite of the resin composition of the present invention and a sheet-like fiber substrate may be formed according to a conventional method such as a hot melt method or a solvent method. Moreover, a prepreg can also be produced by thermally laminating the above-mentioned adhesive sheet from both sides of a sheet-like fiber base material under heating and pressure conditions. The sheet-like fiber base material used for a prepreg is not specifically limited, What is used normally as base materials for prepregs, such as a glass cloth, an aramid nonwoven fabric, a liquid crystal polymer nonwoven fabric, can be used.

Hereinafter, the present invention will be described more specifically with reference to production examples and examples, but the present invention is not limited to the following examples.

In the production example, the purity was calculated by subtracting the moisture value obtained by Karl Fischer from 100% as shown in the following formula.
Purity (%) = 100-moisture value (%)
¹ H-NMR was measured by “AVANCE” 400 manufactured by Bruker.
The melting point was measured with a melting point measuring device MP-500D (manufactured by Yanaco Device Development Laboratory Co., Ltd.).

[Synthesis of Onium Salts Containing Tetraoxycyclic Borate Anions]
Production Example 1
Synthesis example of tetrabutylphosphonium (T-4) -bis [(2S) -2- (hydroxy-kO) propanoate-kO] borate (abbreviation: TBP [(LA) 2B]) (compound (1)) L-lactic acid (60.16 g, 0.60 mol, purity 89.7%) was added to a 41.4 wt% hydroxide aqueous solution (200.00 g, 0.30 mol, Hokuko Chemical TBPH-40) at room temperature, and then boric acid (18.61 g, 0.30 mol, purity 99.5%) was added, and the mixture was stirred at 90 ° C. for 2 hours. After concentration at a bath temperature of about 80 ° C. (water aspirator) for 2 hours, the solution was changed to an ultra-high vacuum pump and further concentrated at 80 ° C. for 2 hours. TBP [(LA) 2B] was obtained as 133.91 g (purity: 98.173 wt%, moisture value: 1.827 wt%) as an oily substance. The yield was 100%. The molar ratio of TBP [(LA) 2B] and H ₂ O was 2: 1.
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 4.42-4.26 (2H, m), 2.29-2.12 (m, 8H), 1.59-1.35 (m, 22H), 1.01-0.95 (m, 14H)

Production Example 2
Synthesis example of tetrabutylphosphonium (T-4) -bis [ethanedioate-kO, -kO] borate (abbreviation: TBP [(OXA) 2B]) (compound (2)) Tetrabutylphosphonium hydroxide 41.4wt% aqueous solution (800.00g, 1.20mol), oxalonic acid (222.43g, 2.40mol, purity 97%) was added at room temperature, then boric acid (74.45g, 1.20mol, purity 99.5%) was added, and at room temperature Stir overnight. The obtained emulsion-like aqueous solution was concentrated at a bath temperature of about 60-80 ° C. (15 mmHg) for 2 hours, further increased to 90 ° C. and further concentrated for 2 hours. TBP [(OXA) 2B] was obtained as 541.19 g (purity: 99.267 wt%, moisture value: 0.733 wt%) as an oily substance. The yield was 100%. The molar ratio of TBP [(OXA) 2B] and H ₂ O was 1: 5.5.
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 2.21-2.09 (8H, m), 1.60-1.45 (m, 16H), 1.00-0.94 (m, 12H)

Production Example 3
1,8-diazabicyclo [5,4,0] -7-undecenium (T-4) -bis [ethanedioate-kO, -kO] borate (abbreviation: DBU [(OXA) 2B]) (compound (3) ) To DBU (50.00 g, 0.32 mol, purity 98 wt%), 100 ml of methyl alcohol and oxalic acid (59.75 g, 0.64 mol, purity 97%) were added at room temperature, and then boric acid (20.00 g, 0.32 mol, purity 99.5%) was added and stirred for 2 hours. Concentration at a bath temperature of 60-90 ° C. (15 mmHg) for 4 hours gave a white solid. Recrystallization from 100 ml of isopropanol gave 71.13 g (98.722 wt%, moisture value; 1.278 wt%) of DBU [(OXA) 2B] as a white solid. The yield was 64.15%, and the molar ratio of DBU [(OXA) 2B] to H ₂ O was 4: 1. The melting point was 107-109 ° C.
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 8.33-8.18 (1H, m), 3.63-3.54 (4H, m), 3.50-3.43 (2H, m), 2.77-2.67 (2H, m), 2.14 -2.03 (2H, m), 1.84-1.67 (6H, m)

Production Example 4
1,8-diazabicyclo [5,4,0] -7-undecenium (T-4) -bis [(2S) -2- (hydroxy-kO) propanoate-kO] borate (abbreviation: DBU [(LA) 2B] ) (Compound (4)) Synthesis Example After adding 200 ml of isopropanol and L-lactic acid (58.57 g, 0.55 mol, purity 85%) to DBU (50.00 g, 0.32 mol, purity 98 wt%) at room temperature, Boric acid (20.00 g, 0.32 mol, purity 99.5%) was added and stirred for 2 hours. By concentrating at a bath temperature of 60 ° C. (35-15 mmHg) for 4 hours, DBU [(LA) 2B] was obtained as 111.70 g (95.808 wt%, moisture value: 4.192 wt%) as an oily substance. DBU [(LA) 2B] and H ₂ O molar ratio of about 1: 1.
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 4.41-4.30 (m, 2H), 3.59-3.50 (m, 4H), 3.42 (brt, 2H), 2.79-2.74 (m, 2H), 2.09-2.02 (m, 2H), 1.82-1.67 (m, 6H), 1.41 (d, 3H), 1.38 (d, 3H)

Production Example 5
1,8-diazabicyclo [5,4,0] -7-undecenium (T-4) -bis [2- (hydroxy-kO) benzoate-kO] borate (abbreviation: DBU [(SA) 2B]) (compound ( Synthesis Example 5)) To DBU (50.00 g, 0.32 mol, purity 98 wt%), 200 ml of isopropyl alcohol was added and then cooled in a water bath. Salicylic acid (89.81 g, 0.64 mol, purity 99%) was added at room temperature, boric acid (20.00 g, 0.32 mol, purity 99.5%) was added, and the mixture was stirred for 3 hours. The obtained slurry was separated and dried under reduced pressure to obtain 128.02 g (purity: 100%, moisture value: 425 ppm) of DBU [(SA) 2B] as a white solid. The molar ratio of DBU [(SA) 2B] and H ₂ O was 1: 0. The melting point was 116-123 ° C.
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 9.61 (1H, brs), 7.87 (2H, dd), 7.43-7.37 (2H, m), 6.95-6.85 (4H, m), 3.39-3.33 (2H , m), 3.33-3.27 (2H, m), 3.18-3.12 (2H, m), 2.58-2.53 (2H, m), 1.80-1.72 (2H, m), 1.64-1.47 (6H, m)

Production Example 6
Synthesis example of 2-methylimidazolium (T-4) -bis [ethanedioate-kO, -kO] borate (abbreviation: 2MZ [(OXA) 2B]) (compound (6)) Oxalic acid (50.00g, 0.54 mol, purity 97 wt%) was added 100 ml of water and boric acid (16.74 g, 0.27 mol, purity 99.5%) and stirred for 1 hour. 2-Methylimidazole (22.56 g, 0.27 mol, purity 98%) was added at room temperature, followed by stirring at 70 ° C. for 2 hours, and further stirring for 2 days. The solvent was distilled off at a bath temperature of 60 ° C. (20 mmHg), 200 ml of isopropyl alcohol was added, and the mixture was stirred at 60 ° C. for 2 hours. After cooling to room temperature over 2 hours, the mixture was further stirred at room temperature for 4 hours. The obtained crystals were filtered and dried under reduced pressure to obtain 32.15 g (purity: 98.310 wt%, moisture: 1.690 wt%) of 2MZ [(OXA) 2B] as a white solid. The yield was 43.47%. The molar ratio of 2MZ [(OXA) 2B] to H ₂ O in the solid was about 4: 1. The melting point was 182-185 ° C.
¹ H-NMR (400 MHz, DMSO-d ₆ ) δ: 7.52 (2H, s), 2.58 (3H, s)

Production Example 7
2-Ethyl-4-methylimidazolium (T-4) -bis [(2S) -2- (hydroxy-kO) propanoate-kO] borate (abbreviation: 2E4MZ [(LA) 2B]) (compound (7)) Synthesis example of 2-ethyl-4-methylimidazole (80.00g, 0.70mol, purity 98%, Shikoku Chemicals 2E4MZ) after adding L-lactic acid (141.64 g, 1.40mol, purity 88.9%) at room temperature Boric acid (43.43 g, 0.70 mol, purity 99.5%) was added and stirred for 2 hours. By concentrating at a bath temperature of 60 ° C. (15-35 mmHg) for 2 hours, 215.62 g (purity: 95.144 wt%, moisture value: 4.856 wt%) of 2E4MZ [(LA) 2B] was obtained as an oily substance. The molar ratio of 2E4MZ [(LA) 2B] and H ₂ O was about 1: 1.
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 6.83 (1H, d), 4.49-4.30 (2H, m), 2.94 (2H, q), 2.29 (3H, s), 1.55-1.30 (9H, m )

Production Example 8
Synthesis example of tetrabutylphosphonium (T-4) -bis [2- (hydroxy-kO) benzoate-kO] borate (abbreviation: TBP [(SA) 2B]) (compound (8)) tetrabutylphosphonium hydroxide 41.4wt % Aqueous solution (500.00g, 0.75mol, Hokuko Chemical TBPH-40) was added salicylic acid (208.94g, 1.50mol, purity 99%) at room temperature, and boric acid (46.53g, 0.75mol, purity 99.5%) was added. In addition, the mixture was stirred at room temperature for 8 hours. The resulting slurry was separated and dried under reduced pressure at 60-70 ° C. for 10 hours to obtain 406.68 g (purity: 98.423%, moisture value: 1.577 wt%) of TBP [(SA) 2B] as a white solid It was. The yield was 98.54%. The molar ratio of TBP [(SA) 2B] and H ₂ O was 2: 1. The melting point was 89-92 ° C.
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 7.90-7.84 (m, 2H), 7.39-7.33 (m, 2H), 6.90-6.81 (m, 4H), 2.13-1.98 (m, 8H), 1.45 -1.30 (m, 16H), 0.91-0.79 (m, 12H)

Production Example 9
Synthesis example of di-1,8-diazabicyclo [5,4,0] -7-undecenium [2,3-dihydroxybutanedioate] diethyl diborate (abbreviation: DBU2TA-TEB mixture) (compound (9)) DBU ( L-tartaric acid (48.55 g, 0.32 mol, purity 99.5%) was added at room temperature, and then 6.25 ml of water and 30 ml of methyl alcohol were added to 100.00 g, 0.64 mol, purity 98 wt%). After intense exotherm, a homogeneous solution was formed. The solution was concentrated at a bath temperature of 60 ° C. (successive pressure) for 4 hours. Triethyl borate (108.82 g, 0.72 mol, purity 99.5%) was added and stirred for 2 hours. DBU2TA-TEB mixture was obtained as 241.41 g, yellow low viscosity oil. The water content was measured and found to be 1.512 wt%. When IR was measured, a strong peak was observed around 1716 cm ⁻¹ , which is characteristic of cyclic borate ester.

Production Example 10
Synthesis example of 2-ethyl-4-methylimidazolium (T-4)-[(2S) -2- (hydroxy-kO) propanoate-kO] diethyl borate (abbreviation: 2E4MZLA-TEB mixture) (compound (10))
To 2-ethyl-4-methylimidazole (60.00 g, 0.55 mol, Shikoku Kasei 2E4MZ), L-lactic acid (58.44 g, 0.55 mol, purity 85%) was added at room temperature. After the exotherm subsided, at room temperature, triethyl borate (105.77 g, 0.70 mol, purity 99.5%) was added and stirred for 2 hours. 216.80 g of 2E4MZLA-TEB mixture was obtained as a yellow low viscosity oil. The water content was measured and found to be 3.706 wt%. When IR was measured, a strong peak was observed in the vicinity of the peak of 1724 cm ⁻¹ characteristic of the cyclic borate ester.

Production Example 11 (Synthesis of Comparative Onium Salt)
Synthesis example of N-acetylglycine tetrabutylphosphonium salt (abbreviation: TBP-N-Ac-Gly) N-acetylglycine (177.19g, 1.50) against 41.4wt% tetrabutylphosphonium hydroxide aqueous solution (1000.28g, 1.50mol) mol, purity 99%) was added at room temperature, followed by stirring for 10 minutes. The solution was concentrated for 4 hours at a bath temperature of 50-90 ° C. (pressure reduction: 13-20 mmHg). The obtained residue was returned to room temperature, and 700 ml of ethyl acetate was added and dissolved uniformly. The obtained solution was concentrated at a bath temperature of 50-90 ° C. (decompression degree: 40-20 mmHg), 573.19 g of TBP-N-Ac-Gly (purity: 98.294 wt%, moisture value: 1.71 wt%), oil Obtained as a substance. The yield was 100%. The molar ratio of TBP [(LA) 2B] to H ₂ O was about 3: 1.
¹ H-NMR (400 MHz, CDCl ₃ ) δ: 6.65 (brs, 1H), 3.62 (d, 2H), 2.33-2.19 (m, 8H), 1.88 (s, 3H), 1.51-1.39 (m, 16H ), 0.94-0.85 (m, 12H)

[Examples and Comparative Examples]
The materials used in the examples and comparative examples will be described.
(A) Epoxy resin Liquid bisphenol A type epoxy resin (“Epicoat 828EL” manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent (184 to 194 g / eq))
Liquid bisphenol F type epoxy resin (“Epicoat 807” manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent (160 to 170 g / eq))
Liquid bisphenol A type epoxy resin (“Epicoat 827” manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent (180 to 190 g / eq))
(B) Onium salt Onium salt of Production Examples 1 to 11 (C) Blocked isocyanate Aromatic dimethylurea compound (“U-3502T” manufactured by San Apro Co., Ltd.)
(D) Storage stabilizer Triethyl borate (TEB, triethyl borate) (Tokyo Chemical Industry “B0520” purity> 97.0%)
(E) Antifoaming agent Silicone paint additive (Toray Dow Corning Co., Ltd., ST86PA)
BYK-1790 manufactured by Big Chemie Japan KK
(F) Rubber particle-containing epoxy resin Kaneace MX-120 manufactured by Kaneka Corporation (SBR 25% by weight Bisphenol A type epoxy resin 75% by weight)
Kaneka Corporation MX-130 (SBR 25% by weight Bisphenol F type epoxy resin 75% by weight) manufactured by Kaneka Corporation

[Measurement and evaluation method]
Evaluation (test) of the properties and physical properties of the resin compositions of Examples and Comparative Examples was performed by the following method.
1. Viscosity RE80 type viscometer (Toki Sangyo Co., Ltd.) is equipped with a cone rotor (rotor code No. 6; 3 ° x R9.7), and 0.2 to 0.3 ml of the resin composition to be measured is placed in the measurement chamber. Weighed with a syringe. During measurement, the temperature of the viscometer measurement chamber was controlled at 25.0 ° C. in an external circulation thermostat. The rotational speed of the rotor was set to 2, 5, and 20 rpm, and the viscosity after 120 seconds at each rotational speed was measured (unit: Pa · s).

2. Thixo ratio The thixo ratio was determined by the following formula based on the above viscosity measurement results.
(Thixotropic ratio) = (Viscosity Pa · s at 2 rpm) / (Viscosity Pa · s at 20 rpm)

3. Gel time (gelation time)
Using a hot plate type gelation tester (GT-D: manufactured by Nisshin Kagaku Co., Ltd.), the time during which the resin composition stopped drawing at 150 ° C. was measured. Specifically, about 0.5 g of a sample (resin composition) is placed on a hot plate type gelation tester, a stopwatch is started at 150 ° C., and a contact circular motion is repeated with a spatula having a tip width of 5 mm, The time until conversion was measured. The contact circular motion is such that the resin is within a range of 25 mm in diameter, the spatula is not lifted while the viscosity of the resin is low, it is at a speed of one revolution per second, and sometimes from the hot plate as the viscosity increases. This vertical movement was repeated until it was lifted 30 mm vertically and the thread-like material was cut.

4). Storage stability (usable time)
The resin composition was placed in a 5 mL polypropylene container (Plasto made by Umano Chemical Container Co., Ltd.), and the time (days) until gelation at 40 ° C. (until the fluidity was lost) was measured.

5. Tensile shear adhesive strength A test piece of a mild steel plate (JISG3141, SPCCD) was wiped with Kimwipe (paper waste made by Nippon Paper Crecia Co., Ltd.) moistened with acetone, and the oil was wiped off. Furthermore, the surface of the bonding surface was polished with an endless belt. At this time, first, about 30 to 40 mm from the end of the mild steel plate was uniformly polished from one direction, and then the second polishing was performed at an angle of 90 ° with respect to the initial polishing mark. Polishing was terminated when the initial and second polishing marks became uniform, and the metal powder was washed with an air brush. The resin composition was uniformly applied to the polished surface of the mild steel sheet in a range of about 12 mm from the end to a thickness of about 1 mm. The coated surface was bonded with two clips with an overlap of about 12 mm and pressed. At this time, the exuded resin composition was immediately wiped off with Kimwipe. The test pieces were evenly arranged in an oven and cured by heating at 130 ° C. for 3 hours to be bonded. Three test pieces were prepared for the same resin. The tensile strength of the obtained test piece was measured with a Tensilon universal testing machine (UTM-5T manufactured by TOYO BALDWIN) (measuring environment: temperature 25 ° C./humidity 40%, tensile speed: 5 mm / min).
Based on the maximum load (N) at which the test piece was broken, the adhesion area (mm ² ) was measured, and the tensile shear bond strength was calculated from the following formula.
Tensile shear bond strength (N / mm ² ) = Maximum load (N) / bond area (mm ² )

6). Measurement of curing calorific value A differential scanning calorimeter (DSC; DSC823e manufactured by METTLER TOLEDO) was used. A 5 mg resin composition was weighed into a special aluminum pan at a temperature rising speed of 5 ° C./min and a temperature measurement range of 25-200 ° C. or 25-250 ° C. to obtain a heat generation chart during resin curing. The calorific value was obtained as the area (mW ° C.) of the exothermic peak of each sample using the dedicated software “STARe Software version 9.01”.

(Examples 1 to 14, 20 to 23, Comparative Examples 1 to 11)
Each resin composition having the composition shown in Tables 1, 2, and 3 below was prepared. Weigh out the specified amount of materials shown in Tables 1, 2, and 3 in a dedicated plastic container, and then use a rotating / revolving vacuum mixer Awatori Rentaro (Sinky Corporation; ARE-250) at room temperature and 2000 rpm Mix for 1 minute and degas for another 1 minute. In addition, the numerical value of the compounding quantity of each material shown to Table 1, 2, 3 is a weight part. Tables 1, 2 and 3 also show the evaluation results of the properties and physical properties of the resin composition.

(Examples 15 to 19, Comparative Example 12)
Each resin composition having the composition shown in Table 4 below was prepared in the same manner as described above, and the viscosity change of the resin composition when stored at 40 ° C. was measured with an E-type viscometer. The results are shown in Table 4. From Table 4, tetrabutylphosphonium (T-4) -bis [ethanedioate-kO, -kO] borate (TBP [(OXA) 2B]), which is an onium salt having a tetraoxycyclic borate anion, is blended even in a small amount. As a result, it can be seen that the increase in viscosity becomes extremely small and the usable time can be extended.

FIG. 1 is a DSC chart obtained by a measurement test of the amount of heat generated by curing the resin compositions of Examples 1 and 13 and Comparative Examples 1, 10, and 11. From the figure, it can be seen that the curing in Comparative Example 11 in which N-acetylglycine tetrabutylphosphonium salt (TBP-N-Ac-Gly) was blended without block isocyanate proceeded at a stretch. Moreover, it turns out that the comparative examples 1 and 10 using TBP [(LA) 2B] and 2E4MZ [(LA) (EtO) 2B] which are onium salts which have a tetraoxy cyclic borate anion cure very slowly. In contrast, Example 1 using TBP [(LA) 2B], which is an onium salt having a tetraoxycyclic borate anion, and blocked isocyanate (U-3502T), and 2E4MZ, which is an onium salt having a tetraoxycyclic borate anion. In Example 13 using [(LA) (EtO) 2B] and blocked isocyanate (U-3502T) in combination, it can be seen that the curing reaction is mild and the reaction is completed relatively quickly.

FIG. 2 is a DSC chart in heat curing of the resin compositions of Examples 15 to 19 and Comparative Example 12. The measurement conditions are the same as those for the curing heat generation measurement test.
From the figure, compared to Comparative Example 12 containing only blocked isocyanate (U-3502T), TBP [(OXA) 2B], which is an onium salt having a tetraoxycyclic borate anion, and blocked isocyanate (U-3502T) were blended. In Examples 15 to 19, it can be seen that the decomposition of the blocked isocyanate (U-3502T) is suppressed on the low temperature side (that is, the curing reaction does not occur), and the curing reaction proceeds and completes rapidly in the high temperature region.

The above evaluation (test) results are summarized in the following considerations.

The N-acetylglycine tetrabutylphosphonium salt (TBP-N-Ac-Gly) used in Comparative Example 11 can be a curing agent for the epoxy resin by itself. However, the period of storage without gelation at a temperature of 40 ° C. is one day, which is problematic in terms of storage stability (usable time). Further, the amount of heat generated by the curing reaction of the epoxy resin is large, and there is a problem in that the cured product is burnt.

From the comparison between Examples 1 to 14 and Comparative Examples 1 to 10 and the comparison between Examples 15 to 19 and Comparative Example 12, an onium salt having a tetraoxycyclic borate anion alone does not function as a curing agent for an epoxy resin. Mixing with an epoxy resin together with a block isocyanate provides a resin composition that is excellent in preservability (longer usable time), and can be cured to increase the curing speed and form a cured product with moderate adhesive strength during heat curing. I was able to confirm that it was possible. Moreover, the calorific value accompanying the curing reaction of the epoxy resin was sufficiently small, and it was confirmed that the resin composition was free from the concern of the problem of occurrence of burnt of the cured product.

The resin composition of the present invention is excellent in preservability (longer usable time), and does not cause a problem of burning of the cured product. Therefore, it can be suitably used for structural material applications such as prepregs where resin scoring during curing is a problem, and adhesives, adhesive sheets, sealants and the like in which adhesiveness is particularly important.
The onium salt of the present invention can be used as an epoxy resin composition containing a blocked isocyanate as a curing agent, acting as a decomposition inhibitor for the blocked isocyanate, and used as a curing retarder that acts to extend usable time or suppress rapid curing. it can. In addition, for example, as a resin additive, an antistatic effect, a filler dispersion effect, a leveling effect, a wettability improving effect, etc. can be expected. As other uses, it is used as an electrolyte for a secondary battery, an additive to a lubricating oil, etc. I can expect to do it.
This application is based on Japanese Patent Application No. 2010-053849 filed in Japan, the contents of which are incorporated in full herein.

Claims (9)

1. (A) An epoxy resin, (B) an onium salt whose anion is a tetraoxycyclic borate anion, and (C) a blocked isocyanate.
2. 2. The resin composition according to claim 1, wherein the (B) tetraoxy cyclic borate anion is a tetraoxy cyclic borate anion in which at least one molecule of hydroxy acid or dicarboxylic acid is chelate-coordinated to a boron atom.
3. (B) The tetraoxy cyclic borate anion is represented by the general formula (I):
   

   

   (Wherein R ₁ is an organic group, and —O—R ₁ —O— represents a residue of a hydroxy acid bonded to a boron atom by releasing one proton from each hydroxyl group and one carboxyl group, respectively. Alternatively, two carboxyl groups each release a proton to indicate a dicarboxylic acid residue bonded to a boron atom.)
   Or a bicyclic tetraoxycyclic borate anion represented by the general formula (II):
   

   

   (Wherein R _1, —O—R ₁ —O— are as defined above, R ₂ is an alkoxy group, and n is 1 or 2.) The resin composition according to claim 1, wherein:
4. The cation of the onium salt is a secondary or tertiary ammonium cation containing a protonated nitrogen atom or a quaternary phosphonium cation containing a protonated phosphorus atom. The resin composition as described.
5. The resin composition according to any one of claims 1 to 4, wherein the melting point or softening point of the onium salt is 200 ° C or lower.
6. 6. The resin composition according to claim 1, wherein the blocked isocyanate is a compound obtained by reacting an isocyanate compound with a compound in which an active hydrogen atom is bonded to a nitrogen atom. .
7. An adhesive comprising the resin composition according to any one of claims 1 to 6.
8. The anion is represented by the general formula (Ia):
   

   

   (In the formula, —O—R ₃ —O— is a residue of oxalic acid in which two carboxyl groups each release a proton and bonded to a boron atom, or one hydroxyl group and one carboxyl group. Each group releases a proton, indicating a residue of lactic acid or salicylic acid bonded to a boron atom.)
   A bicyclic tetraoxycyclic borate anion represented by:
   In the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia), when —O—R ₃ —O— is a residue of oxalic acid, the cation is an ammonium cation or a phosphonium cation. Or a sulfonium-based cation,
   When —O—R ₃ —O— in the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia) is a residue of lactic acid, the cation is a phosphonium cation or a sulfonium cation. Yes,
   When the —O—R ₃ —O— in the formula of the bicyclic tetraoxycyclic borate anion represented by the general formula (Ia) is a salicylic acid residue, the cation is a sulfonium cation. An onium salt.
9. The anion is represented by the general formula (II):
   

   

   (Wherein R _1, —O—R ₁ —O—, R ₂ , and n are as defined above), a monocyclic tetraoxycyclic borate anion,
   An onium salt, wherein the cation is an ammonium cation, a phosphonium cation or a sulfonium cation.

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