JP2017105949A - Method for producing aluminium chelate-based latent curing agent and thermosetting epoxy resin composition - Google Patents

Abstract

An aluminum chelate-based latent curing agent in which an aluminum chelating agent is held in porous resin particles obtained by interfacial polymerization of a polyfunctional isocyanate compound is mixed with an epoxy resin and a silane compound together with an organic solvent such as PGMEA. Aluminum that, when blended to prepare a one-component thermosetting epoxy resin composition, can exhibit good storage stability at room temperature without impairing the low-temperature rapid curing property of the resin composition. A chelate latent curing agent is provided. An aluminum chelate-based latent curing agent for curing a thermosetting epoxy resin contains a volatile organic solvent in which an aluminum chelating agent is held in a porous interfacial polymer of a polyfunctional isocyanate compound. The aluminum chelating agent solution is added to the porous interfacial polymer by removing the volatile organic solvent, and then the alumina chelating agent is formed on the surface of the porous interfacial polymer. is there. [Selection] Figure 1

Description

  The present invention relates to a method for producing an aluminum chelate-based latent curing agent for curing a thermosetting epoxy resin, a thermosetting urea resin, a thermosetting melamine resin, a thermosetting phenol resin, or the like.

  A particulate aluminum chelate-based latent curing agent in which an aluminum chelating agent is held in a porous resin particle derived from a polyfunctional isocyanate compound has been put to practical use as a curing agent that exhibits low-temperature rapid curing activity for an epoxy resin. Such an aluminum chelate-based latent curing agent is an oil obtained by dissolving or dispersing a polyfunctional isocyanate compound and an aluminum chelating agent having a property capable of curing an epoxy resin (epoxy curing ability) in a poorly water-soluble organic solvent. It is manufactured by introducing the phase into an aqueous phase containing a dispersant and interfacial polymerization.

  Recently, in order to improve the curing speed of a thermosetting epoxy resin composition containing an aluminum chelate-based latent curing agent, the aluminum chelate-based latent curing agent once obtained is dissolved in an organic solvent. Immersion in an aluminum chelating agent solution, impregnating the solution into the porous resin constituting the aluminum chelating latent curing agent, thereby additionally filling the aluminum chelating latent curing agent with the aluminum chelating agent Has been proposed (Patent Document 1).

JP 2008-156570 A

  However, as described in Patent Document 1, in the case of an aluminum chelate-based latent curing agent additionally filled with an aluminum chelating agent having an epoxy curing ability, the content of the aluminum chelating agent in the curing agent increases. However, the concentration of the aluminum chelating agent in the aluminum-based latent curing agent cannot be increased above the concentration of the aluminum chelating agent in the aluminum chelating agent solution, and the curing rate of the thermosetting epoxy resin composition cannot be increased. There is a problem that it is not possible to sufficiently meet the demand of the industry for further improvement.

  In addition, in the case of an aluminum chelate-based latent curing agent additionally filled with an aluminum chelating agent, even if the aluminum chelating agent present on the surface is removed by washing with an organic solvent such as cyclohexane, active aluminum is present in the vicinity of the surface. The chelating agent is present at a relatively high concentration. For this reason, such an aluminum chelate-based latent curing agent is blended with an epoxy resin and a silane compound together with an organic solvent such as propylene glycol monomethyl ether acetate (PGMEA) to form a one-component thermosetting epoxy resin composition. In the case where the aluminum chelating agent is dissolved in the organic solvent, the curing reaction proceeds, and the storage stability at room temperature cannot be said to be sufficient.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and an aluminum chelate-based latent curing in which an aluminum chelating agent is held in porous resin particles obtained by interfacial polymerization of a polyfunctional isocyanate compound. Content of the aluminum chelating agent in excess of the aluminum chelating agent concentration of the aluminum chelating agent solution prepared when the aluminum chelating agent is additionally filled in the aluminum chelating latent curing agent by immersing the agent in the aluminum chelating agent solution It is to be able to produce an aluminum chelate-based latent curing agent with increased slag. At the same time, a one-component thermosetting type prepared by blending an aluminum chelate latent curing agent additionally filled with an aluminum chelating agent with an epoxy resin and a silane compound together with an organic solvent such as PGMEA. It is to be able to produce an aluminum chelate-based latent curing agent that enables an epoxy resin composition to exhibit good storage stability at room temperature.

  The present inventor immerses the aluminum chelate-based latent curing agent in the aluminum chelating agent solution, so that when the aluminum chelate-based latent curing agent is additionally filled with the aluminum chelating agent, the immersion is performed in the aluminum chelating agent. It was found that the aluminum chelating agent concentration in the aluminum chelating agent solution increases when the solvent is removed from the solution, and as a result, the aluminum chelating agent can be highly filled with the aluminum chelating latent curing agent. In addition, the present inventor performs surface activity suppression treatment by forming an alumina coating on the surface of the particulate curing agent highly filled with the aluminum chelating agent, thereby substantially reducing the aluminum chelating agent present on the surface. An aluminum chelate-based latent curing agent that can be completely deactivated and latentized, and that has been subjected to such surface activity suppression treatment, is blended with an epoxy resin and a silane compound together with an organic solvent such as PGMEA. The liquid thermosetting epoxy resin composition has been found to exhibit good storage stability at room temperature without impairing the low temperature rapid curability, and has led to the completion of the present invention.

  That is, this invention is a manufacturing method of the aluminum chelate type | system | group latent hardening | curing agent currently hold | maintained at the porous resin obtained by interfacially polymerizing a polyfunctional isocyanate compound, Comprising: The following process (A) It is a manufacturing method characterized by having-(C).

(Process A: Particulate curing agent preparation process)
An oil phase obtained by dissolving or dispersing an aluminum chelating agent and a polyfunctional isocyanate compound in a volatile organic solvent is subjected to interfacial polymerization of the polyfunctional isocyanate compound by stirring while heating in an aqueous phase containing the dispersant. And a step of preparing a particulate curing agent by holding an aluminum chelating agent in the porous resin obtained thereby.

(Process B: Aluminum chelating agent additional filling process)
The particulate curing agent obtained in step A is dispersed and mixed in an aluminum chelating agent solution in which an aluminum chelating agent is dissolved in a volatile organic solvent, and the volatile organic solvent is removed while stirring the obtained dispersion mixture. The step of additionally filling an aluminum chelating agent into the particulate curing agent.

(Process C: Surface activity suppression treatment process)
An alumina coating is formed on the surface of the particulate curing agent additionally filled with the aluminum chelating agent, and the surface activity of the particulate curing agent is suppressed, thereby obtaining a latent aluminum chelate-based latent curing agent. Process.

  As the surface activity suppression treatment in Step C, it is preferable to stir the particulate curing agent in the hydrous alumina sol dispersion. As such a hydrous alumina sol dispersion, a mixture of 1 to 70 parts by mass of alumina sol and 30 to 99 parts by mass of a hydrous medium is preferable. The alumina sol generally corresponds to a 1-50% colloidal aqueous solution of boehmite alumina fibers. Specifically, the alumina has an average fiber length of 1 to 10,000 nm and an aspect ratio (average fiber length / average fiber width) of 30 to 5000. Those in which fibers are dispersed in a water-containing medium are preferred. Here, the alumina fiber content in the alumina sol is preferably 1 to 30% by mass. Examples of the water-containing medium include water and a mixed solvent with an organic solvent (methanol, ethanol, acetone, THF, etc.) miscible with water. The content of water in the mixed solvent is preferably 20 to 100% by mass or more, more preferably 50 to 100% by mass.

  Moreover, this invention provides the thermosetting epoxy resin composition containing the aluminum chelate type | system | group latent hardening | curing agent manufactured by the above-mentioned manufacturing method, an epoxy resin, and a silane type compound.

  In the method for producing an aluminum chelate-based latent curing agent of the present invention, an aluminum chelating agent having epoxy curing ability is held in a porous resin obtained by interfacial polymerization of a polyfunctional isocyanate compound, and then the porosity is further increased. The resin is additionally filled with an aluminum chelating agent. For this reason, the obtained aluminum chelate-based latent curing agent can rapidly cure the epoxy resin, and can exhibit sharp thermal responsiveness in a low temperature region. In addition, an alumina coating is formed on the surface of the particulate curing agent and the surface activity of the particulate curing agent is suppressed, whereby the activity of the aluminum chelating agent remaining on the surface is suppressed. Therefore, the aluminum chelate-based latent curing agent produced by the production method of the present invention exhibits excellent solvent resistance, and is obtained by blending it with an organic solvent such as an epoxy resin, a silane compound and PGMEA. Even for the thermosetting epoxy resin composition, good storage stability can be realized at room temperature.

FIG. 1 is a DSC chart of a thermosetting epoxy resin composition using the particulate curing agent or aluminum chelate-based latent curing agent prepared in Control Example, Examples 1 and 2 and Comparative Examples 1 and 2. FIG. 2 is an electron micrograph (5000 magnifications) of the aluminum chelate-based latent curing agent of Example 2. 3 is an electron micrograph (15000 times) of the aluminum chelate-based latent curing agent of Example 2. FIG.

<< Production method of aluminum chelate-based latent curing agent >>
The method for producing an aluminum chelate-based latent curing agent of the present invention in which an aluminum chelating agent is held in a porous resin obtained by interfacial polymerization of a polyfunctional isocyanate compound includes the following steps (A) to (C). Have Hereinafter, it demonstrates in detail for every process.

<Step A: Particulate curing agent preparation step>
First, an oil phase obtained by dissolving or dispersing an aluminum chelating agent and a polyfunctional isocyanate compound in a volatile organic solvent is heated while being added to an aqueous phase containing a dispersant (usually the mixture becomes 30 to 90 ° C). In this way, the polyfunctional isocyanate compound is interfacially polymerized by stirring while heating), and the porous chelate obtained thereby holds the aluminum chelating agent to prepare a particulate curing agent. The particulate curing agent can be pulverized into primary particles by a known pulverizer after being filtered, washed and dried as necessary.

  A porous resin derived from a polyfunctional isocyanate compound that constitutes such a particulate curing agent is a part of the isocyanate group that undergoes hydrolysis during the interfacial polymerization to become an amino group, which reacts with the amino group. Thus, a urea bond is produced and polymerized, and can be regarded as porous polyurea. When the particulate curing agent comprising such a porous resin and the aluminum chelating agent held in the pores is heated, the clear reason is unknown, but the aluminum chelating agent held in the porous resin is unknown. However, it can come into contact with a silane compound such as a silane coupling agent or a silanol compound existing outside the porous resin to initiate cationic polymerization of the epoxy resin.

(Preparation of oil phase in interfacial polymerization)
In this production method, first, an aluminum chelating agent and a polyfunctional isocyanate compound are dissolved or dispersed in a volatile organic solvent to prepare an oil phase in interfacial polymerization.

  The blending ratio of the aluminum chelating agent and the polyfunctional isocyanate compound is that if the blending amount of the aluminum chelating agent is too small, the curability of the epoxy resin to be cured is lowered. Therefore, the aluminum chelating agent is preferably 10 to 500 parts by mass, more preferably 10 to 300 parts by mass with respect to 100 parts by mass of the polyfunctional isocyanate compound constituting the porous resin.

  In this oil phase, a silane compound may be blended in order to improve fast curability.

  When mix | blending a silane type compound with an oil phase, Preferably it is 1-300 mass parts with respect to 100 mass parts of aluminum chelating agents, More preferably, it mix | blends by 1-200 mass parts. If it is this range, favorable quick-cure property is realizable.

  Moreover, in order to improve low temperature curability, you may mix | blend a radically polymerizable compound and a radical polymerization initiator with this oil phase.

  Moreover, when mix | blending a radically polymerizable compound and a radical polymerization initiator with an oil phase, Preferably it is 1-70 mass parts with respect to 100 mass parts of polyfunctional isocyanate compounds, More preferably, 1-50 masses. Blend in parts. If it is this range, favorable low-temperature curability can be implement | achieved. In this case, the radical polymerization initiator is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the radical polymerizable compound in order to realize smooth radical polymerization. Blend.

  When dissolving or dispersing an aluminum chelating agent and a polyfunctional isocyanate compound, a silane compound, a polyfunctional radical polymerizable compound, and a radical polymerization initiator, which are blended as necessary, in a volatile organic solvent, it is performed at room temperature under atmospheric pressure. May be mixed and stirred, but may be heated if necessary.

  Here, the reason for using the volatile organic solvent is as follows. That is, when a high boiling point solvent having a boiling point exceeding 300 ° C. as used in a normal interfacial polymerization method is used, the organic solvent does not volatilize during the interfacial polymerization, so the contact probability with isocyanate-water does not increase. This is because the degree of progress of interfacial polymerization between them becomes insufficient. Therefore, it is difficult to obtain a polymer having good shape retention even when interfacial polymerization is performed, and even when it is obtained, when the high boiling point solvent is still taken into the polymer and it is blended in a thermosetting resin composition In addition, the high boiling point solvent adversely affects the physical properties of the cured product of the thermosetting resin composition. For this reason, in this manufacturing method, it is preferable to use a volatile thing as an organic solvent used when preparing an oil phase.

  Examples of such volatile organic solvents include aluminum chelating agents and polyfunctional isocyanate compounds, silane-based compounds and polyfunctional radical polymerizable compounds and radical polymerization initiators that are blended as necessary (respective solubility). Is preferably 0.1 g / ml (organic solvent) or more) and does not substantially dissolve in water (the solubility of water is 0.5 g / ml (organic solvent) or less) at atmospheric pressure. Those having a boiling point of 100 ° C. or lower are preferred. Specific examples of such volatile organic solvents include alcohols, acetate esters, ketones and the like. Among these, ethyl acetate is preferable in terms of high polarity, low boiling point, and poor water solubility.

  The amount of the volatile organic solvent used is small relative to 100 parts by mass of the total amount of the aluminum chelating agent and the polyfunctional isocyanate compound, and the silane compound, polyfunctional radical polymerizable compound and radical polymerization initiator to be blended as necessary. If the amount is too large, the particle size and the curing characteristics are polydispersed. If the amount is too large, the curing characteristics are lowered.

  Note that the viscosity of the oil phase solution can be lowered by using a relatively large amount of the volatile organic solvent within the range of the volatile organic solvent used. As a result, the oil phase droplets in the reaction system can be made finer and more uniform, and the resulting latent hardener particle size can be controlled to submicron to several microns. The particle size distribution can be monodispersed. The viscosity of the solution that becomes the oil phase is preferably set to 1 to 500 mPa · s.

(Preparation of aqueous phase in interfacial polymerization)
The aqueous phase is obtained by dissolving a dispersant in water. As the dispersant, a known dispersant used for interfacial polymerization can be used. For example, polyvinyl alcohol (PVA), carboxymethyl cellulose, gelatin and the like, among which polyvinyl alcohol (PVA) can be preferably used. The usage-amount of a dispersing agent is 0.1-10.0 mass% of an aqueous phase normally. Moreover, the desalted water can be preferably used as the water.

  When PVA is used as a dispersing agent, the polyfunctional isocyanate compound and the like are emulsified and dispersed in the aqueous phase, so that the hydroxyl group of PVA reacts with the polyfunctional isocyanate compound. It may adhere to the periphery of the particle, or the particle shape itself may be deformed. In order to prevent this phenomenon, the reactivity between the polyfunctional isocyanate compound and water is promoted, or the reactivity between the polyfunctional isocyanate compound and PVA is suppressed.

  In order to promote the reactivity between the polyfunctional isocyanate compound and water, the blending amount of the aluminum chelating agent is preferably ½ or less, more preferably ３ or less, based on the weight of the polyfunctional isocyanate compound. Thereby, the probability that a polyfunctional isocyanate compound and water will contact increases, and it becomes easy for a polyfunctional isocyanate compound and water to react before PVA contacts an oil phase droplet surface.

  Moreover, in order to suppress the reactivity of a polyfunctional isocyanate compound and PVA, increasing the compounding quantity of the aluminum chelating agent in an oil phase is mentioned. Specifically, the blending amount of the aluminum chelating agent is preferably at least equal to, more preferably 1.0 to 2.0 times, based on the weight of the polyfunctional isocyanate compound. Thereby, the isocyanate density | concentration in the oil phase droplet surface falls. Furthermore, since the polyfunctional isocyanate compound has a higher reaction rate (interfacial polymerization) with the amine formed by hydrolysis than the hydroxyl group, the reaction probability between the polyfunctional isocyanate compound and PVA can be lowered.

(Implementation of interfacial polymerization)
Next, in this manufacturing method, the interfacial polymerization is performed by putting the oil phase into the aqueous phase and stirring with heating. When a polyfunctional radically polymerizable compound and a radical polymerization initiator are blended in the oil phase, radical polymerization is simultaneously performed. Thereby, the porous resin derived from a polyfunctional isocyanate compound is produced, and the aluminum chelating agent is retained therein, and a particulate curing agent is obtained.

  This holding mode is not a microcapsule having a simple structure in which the core of the aluminum chelating agent is covered with a porous resin shell, but the aluminum chelating agent is present in many fine pores existing in the porous resin matrix. It has a structure that is captured and held.

  The shape of the particulate curing agent obtained by interfacial polymerization is spherical, and its particle size (which can be regarded as the particle size of the aluminum chelate-based latent curing agent) is preferably 0 from the viewpoint of curability and dispersibility. In addition, the pore size is preferably 5 to 150 nm from the viewpoint of curability and latency.

  In addition, when the degree of cross-linking of the porous resin to be used is too small, the potential of the particulate curing agent decreases, and when it is too large, the thermal response tends to decrease. Therefore, it is preferable to adjust the degree of cross-linking with the number of isocyanate functional groups, etc., according to the intended use of the particulate curing agent. Here, the degree of crosslinking of the porous resin can be measured by a micro compression test.

  The blending amount of the oil phase with respect to the aqueous phase in the interfacial polymerization is polydispersed when the oil phase is too small, and agglomeration occurs when the amount is too large. 70 parts by mass.

  As the emulsification conditions in the interfacial polymerization, stirring conditions (stirring device homogenizer; stirring speed of 6000 rpm or more) such that the size of the oil phase is preferably 0.5 to 100 μm are usually obtained at a temperature of 30 to 80 ° C. under atmospheric pressure. The conditions of stirring with heating for 2 to 12 hours can be mentioned.

  After the completion of the interfacial polymerization (radical polymerization performed as necessary), the particulate polymer can be obtained by filtering the polymer fine particles, followed by natural drying or vacuum drying.

  Type and amount of polyfunctional isocyanate compound, type and amount of aluminum chelating agent, interfacial polymerization conditions, or type and amount of silane compound, polyfunctional radical polymerizable compound and radical polymerization initiator, radical polymerization conditions By changing the value, it is possible to control the curing characteristics of the aluminum chelate-based latent curing agent that is the production target. For example, if the polymerization temperature is lowered, the curing temperature can be lowered, and conversely, if the polymerization temperature is raised, the curing temperature can be raised.

(Aluminum chelating agent)
As an aluminum chelating agent mix | blended with an oil phase, the complex compound which three (beta) -ketoenolate anions represented by Formula (1) coordinated to aluminum is mentioned.

Here, R ¹ , R ² and R ³ are each independently an alkyl group or an alkoxyl group. Examples of the alkyl group include a methyl group and an ethyl group. Examples of the alkoxyl group include a methoxy group, an ethoxy group, and an oleyloxy group.

  Specific examples of the aluminum chelating agent represented by the formula (1) include aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum monoacetylacetonate Examples thereof include bisoleyl acetoacetate, ethyl acetoacetate aluminum diisopropylate, and alkyl acetoacetate aluminum diisopropylate.

(Polyfunctional isocyanate compound)
The polyfunctional isocyanate compound blended in the oil phase is preferably a compound having two or more isocyanate groups, preferably three isocyanate groups in one molecule. As a more preferred example of such a trifunctional isocyanate compound, a TMP adduct of formula (2) obtained by reacting 3 mol of a diisocyanate compound with 1 mol of trimethylolpropane, and a formula (3) obtained by self-condensing 3 mol of a diisocyanate compound. An isocyanurate of formula (4) and a biuret of formula (4) obtained by condensing the remaining 1 mol of diisocyanate with diisocyanate urea obtained from 2 mol of 3 mol of diisocyanate compound.

  In the above formulas (2) to (4), the substituent R is a portion excluding the isocyanate group of the diisocyanate compound. Specific examples of such diisocyanate compounds include toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, m-xylylene diisocyanate, hexamethylene diisocyanate, hexahydro-m-xylylene diisocyanate, isophorone diisocyanate, methylene diphenyl-4. , 4'-diisocyanate and the like.

(Silane compounds)
As described in paragraphs 0007 to 0010 of JP-A No. 2002-212537, the silane compound that can be blended in the oil phase is the same as the aluminum chelate agent held in the aluminum chelate latent curing agent. And has a function of initiating cationic polymerization of a thermosetting resin (for example, thermosetting epoxy resin). Therefore, the effect of promoting the curing of the epoxy resin can be obtained by using such a silane compound together. Examples of such silane compounds include highly sterically hindered silanol compounds and silane coupling agents having 1 to 3 lower alkoxy groups in the molecule. In the silane coupling agent molecule, a group having reactivity to the functional group of the thermosetting resin, for example, vinyl group, styryl group, acryloyloxy group, methacryloyloxy group, epoxy group, amino group, mercapto group However, since the latent curing agent of the present invention is a cationic curing agent, the amino group or the mercapto group substantially generates the generated cationic species. Can be used when not captured.

  When a highly sterically hindered silanol compound is contained as a silane compound in the oil phase, if the amount of the highly sterically hindered silanol compound is too small, the curing rate will be slow, and if it is too large, the potential will be lowered. The silanol compound is preferably 10 to 300 parts by weight, more preferably 10 to 150 parts by weight with respect to 100 parts by weight of the chelating agent.

  Unlike a conventional silane coupling agent having a trialkoxy group, a highly sterically hindered silanol compound that can be blended in an oil phase is an arylsilaneol having a chemical structure of the following formula (A).

  In the formula, m is 2 or 3, preferably 3, provided that the sum of m and n is 4. Therefore, the silanol compound of the formula (A) becomes a mono or diol form. “Ar” is an aryl group which may be substituted, and examples of the aryl group include a phenyl group, a naphthyl group (for example, 1 or 2-naphthyl group), an anthracenyl group (for example, 1, 2, or 9-anthracenyl group). Benz [a] -9-anthracenyl group), phenaryl group (eg 3 or 9-phenaryl group), pyrenyl group (eg 1-pyrenyl group), azulenyl group, fluorenyl group, biphenyl group (eg 2,3 Or 4-biphenyl group), thienyl group, furyl group, pyrrolyl group, imidazolyl group, pyridyl group, and the like. Of these, a phenyl group is preferable from the viewpoint of availability and cost. The m Ars may be the same or different, but are preferably the same from the viewpoint of availability.

  These aryl groups can have 1 to 3 substituents, such as halogen such as chloro and bromo; trifluoromethyl; nitro; sulfo; carboxyl; alkoxycarbonyl such as methoxycarbonyl and ethoxycarbonyl; Electron-withdrawing groups; alkyl such as methyl, ethyl and propyl; alkoxy such as methoxy and ethoxy; hydroxy; amino; monoalkylamino such as monomethylamino; and electron-donating groups such as dialkylamino such as dimethylamino. In addition, the acidity of the hydroxyl group of silanol can be increased by using an electron withdrawing group as a substituent, and conversely, the acidity can be lowered by using an electron donating group, so that the curing activity can be controlled. Become. Here, the substituents may be different for each of the m Ars, but the substituents are preferably the same for the m Ars from the viewpoint of availability. Further, only some Ar may have a substituent, and other Ar may not have a substituent. Specific examples of the phenyl group having a substituent include 2, 3, or 4-methylphenyl group; 2,6-dimethyl, 3,5-dimethyl, 2,4-dimethyl, 2,3-dimethyl, 2,5- Examples include dimethyl or 3,4-dimethylphenyl group; 2,4,6-trimethylphenyl group; 2 or 4-ethylphenyl group.

  Among the silanol compounds of the formula (A), preferred are triphenylsilanol and diphenylsilanediol. Particularly preferred is triphenylsilanol.

  On the other hand, when a silane coupling agent having 1 to 3 lower alkoxy groups in the molecule is used as the silane compound, if the amount of the silane coupling agent in the oil phase is too small, the addition effect cannot be expected, and the amount is too large. Since the influence of the interfacial polymerization inhibition reaction by silanol generated from the silane coupling agent occurs, it is preferably 1 to 50 parts by mass, more preferably 1 to 30 parts by mass with respect to 100 parts by mass of the aluminum chelating agent.

  Specific examples of silane coupling agents that can be incorporated into the oil phase include vinyl tris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-styryltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane. , Γ-acryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β- (Aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltri Examples include methoxysilane and γ-chloropropyltrimethoxysilane.

(Radically polymerizable compound)
Further, the radically polymerizable compound that can be blended in the oil phase simultaneously undergoes radical polymerization during the interfacial polymerization of the polyfunctional isocyanate compound, thereby improving the mechanical properties of the porous resin that becomes the microcapsule wall. Thereby, the thermal responsiveness at the time of epoxy resin hardening, especially a sharp thermal responsiveness in a low-temperature area | region is realizable. The reason for this is not clear, but interfacial polymerization and radical polymerization occur at the same time, and a phase separation structure is formed in the porous resin. As a result, the crosslink density of the polyurea-urethane moiety is smaller than the homopolymerization system of the isocyanate compound. This is considered to be because.

  Such radically polymerizable compounds preferably have one or more carbon-carbon unsaturated bonds in the molecule, and include so-called monofunctional radically polymerizable compounds and polyfunctional radically polymerizable compounds. In the invention, the radical polymerizable compound preferably contains a polyfunctional radical polymerizable compound. This is because by using a polyfunctional radically polymerizable compound, it becomes easier to realize sharp thermal responsiveness in a low temperature region. Also in this sense, the radical polymerizable compound preferably contains a polyfunctional radical polymerizable compound at least 30% by mass or more, more preferably at least 50% by mass or more.

  Examples of the monofunctional radically polymerizable compound include monofunctional vinyl compounds such as styrene and methylstyrene, and monofunctional (meth) acrylate compounds such as butyl acrylate. Examples of the polyfunctional radical polymerizable compound include polyfunctional vinyl compounds such as divinylbenzene, and polyfunctional (meth) acrylate compounds such as 1,6-hexanediol diacrylate and trimethylolpropane triacrylate. Of these, polyfunctional vinyl compounds, particularly divinylbenzene, can be preferably used from the viewpoints of latency and heat responsiveness.

  The polyfunctional radical polymerizable compound may be composed of a polyfunctional vinyl compound and a polyfunctional (meth) acrylate compound. By using together in this way, the effect that a thermal responsiveness is changed or a reactive functional group can be introduce | transduced is acquired.

(Radical polymerization initiator)
The radical polymerization initiator that can be blended in the oil phase is one that can initiate radical polymerization under the interfacial polymerization conditions of the polyfunctional isocyanate compound. For example, a peroxide initiator, an azo initiator An agent or the like can be used.

<Process B: Aluminum chelating agent additional filling process>
Next, the particulate curing agent obtained in Step A is dispersed and mixed in an aluminum chelating agent solution in which an aluminum chelating agent is dissolved in a volatile organic solvent, and the volatile organic solvent is stirred while stirring the obtained dispersion mixture. By removing, an aluminum chelating agent is additionally filled in the particulate curing agent. By removing the volatile solvent, the concentration of the aluminum chelating agent in the aluminum chelating agent solution increases, resulting in an increase in the amount of aluminum chelating agent retained in the pores of the porous resin of the particulate curing agent. To do. The particulate curing agent additionally filled with an aluminum chelating agent can be pulverized into primary particles by a known pulverizer after filtering, washing and drying as necessary.

  As the aluminum chelating agent used in the step B, an aluminum chelating agent different from that used in the step A can be used, but it is preferable to use the same one from the viewpoint of management of the amount used. Moreover, as a volatile organic solvent which melt | dissolves an aluminum chelating agent, the volatile organic solvent used with the oil phase of the process A can be used.

  The aluminum chelating agent concentration in the aluminum chelating agent solution is preferably 5 to 80% by mass, more preferably 20 to 60% by mass. If it is this range, favorable permeability to an aluminum chelating agent solution to a particulate hardening agent is realizable.

  The blending amount of the particulate curing agent with respect to 100 parts by weight of the aluminum chelating agent solution is preferably 1 to 70 parts by weight, more preferably 10 to 50 parts by weight. Within this range, good dispersion stability of the particulate curing agent can be realized.

  Known techniques can be used for the dispersing and mixing operation of the particulate curing agent in the aluminum chelating agent solution and the stirring operation of the dispersion mixture.

  Removal of the volatile organic solvent from the dispersion mixture is an operation of increasing the concentration of the aluminum chelating agent in the dispersion mixture, and an operation of removing the aluminum chelating agent by any method can be adopted as long as the aluminum chelating agent is not decomposed. For example, heating the dispersion mixture to a temperature higher than the boiling point of the volatile organic solvent used, depressurizing the stirring system of the dispersion mixture, or air blowing the surface of the dispersion mixture, etc. It is done.

  Regarding the removal of the volatile organic solvent, the degree of removal is such that preferably 40 to 100% of the input volatile organic solvent is removed. Within this range, the aluminum chelating agent can be highly filled in the particulate curing agent. The removal rate is preferably 100 to 1000 mL / hour. Within this range, the aluminum chelating agent can be captured at a high concentration in the particulate curing agent.

<Process C: Surface activity suppression treatment process>
Next, an alumina coating is formed on the surface of the particulate curing agent additionally filled with the aluminum chelating agent, and the surface activity of the particulate curing agent is suppressed, thereby making the latent aluminum chelate latent curing agent latent. To get. Preferred conditions for the surface activity suppression treatment include stirring the particulate curing agent in a hydrous alumina sol dispersion, preferably at a temperature of 10 to 80 ° C. for 1 to 20 hours at 50 to 300 rpm.

  Examples of the hydrous alumina sol dispersion include a mixture of 1 to 70 parts by mass of alumina sol and preferably 30 to 99 parts by mass of a hydrous medium. Here, examples of the water-containing medium include water and a mixed solvent with an organic solvent (methanol, ethanol, acetone, THF, etc.) miscible with water. The content of water in the mixed solvent is preferably 20 to 100% by mass, more preferably 50 to 100% by mass.

  As the alumina sol, a known alumina sol can be used. The average fiber length is preferably 1 to 10000 nm, more preferably 100 to 8000 nm, and the aspect ratio (average fiber length / average fiber width) is preferably 30. ˜5000, more preferably 100 to 3000 alumina fibers dispersed in a water-containing medium can be preferably used. The average fiber length and average fiber width can be obtained from the average values measured from electron micrographs. The “average” is an arithmetic average. The alumina fiber content in such an alumina sol is preferably 1 to 50% by mass, more preferably 1 to 30% by mass.

  The obtained aluminum chelate-based latent curing agent can be centrifuged while being washed with distilled water as necessary, dried at 10 to 100 ° C., and further crushed with a known crushing apparatus. .

  From the viewpoint of curing stability, the aluminum chelate-based latent curing agent is preferably substantially free of the organic solvent used in Steps A to C, specifically 1 ppm or less.

<< Thermosetting epoxy resin composition >>
By adding the aluminum chelate-based latent curing agent of the present invention to an epoxy resin and a silane-based compound, a low-temperature fast-curing thermosetting epoxy resin composition can be provided. Such a thermosetting epoxy resin composition is also part of the present invention.

  If the content of the aluminum chelate-based latent curing agent in the thermosetting epoxy resin composition of the present invention is too small, it will not be cured sufficiently, and if it is too large, the resin properties of the cured product of the composition (for example, acceptable (Flexibility) is lowered, and is 1 to 70 parts by mass, preferably 1 to 50 parts by mass with respect to 100 parts by mass of the epoxy resin.

  The epoxy resin constituting the thermosetting epoxy resin composition of the present invention is used as a film forming component. As such an epoxy resin, not only an alicyclic epoxy resin but also a glycidyl ether type epoxy resin that could not be conventionally used in a mixed system of an aluminum chelate-based latent curing agent and a silanol compound can be used. . Such a glycidyl ether type epoxy resin may be liquid or solid, and preferably has an epoxy equivalent of usually about 100 to 4000 and having two or more epoxy groups in the molecule. For example, bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, ester type epoxy resin and the like can be mentioned. Among these, bisphenol A type epoxy resins can be preferably used from the viewpoint of resin characteristics. These epoxy resins also include monomers and oligomers.

  In addition to such a glycidyl ether type epoxy resin, the thermosetting epoxy resin composition of the present invention can be used in combination with an oxetane compound in order to sharpen the exothermic peak. Preferred oxetane compounds include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 4,4′-bis [(3-ethyl- 3-Oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylic acid bis [(3-ethyl-3-oxetanyl)] methyl ester, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- ( 2-ethylhexyloxymethyl) oxetane, di [1-ethyl (3-oxetanyl)] methyl ether, 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane, oxetanylsilsesquioxane, Phenol novolac oxetane and the like can be mentioned. When using an oxetane compound, the usage-amount is with respect to 100 mass parts of epoxy resins, Preferably it is 10-100 mass parts, More preferably, it is 20-70 mass parts.

  As described in paragraphs 0007 to 0010 of JP-A No. 2002-212537, the silane compound to be blended in the thermosetting epoxy resin composition of the present invention was held in the aluminum chelate latent curing agent. It has a function of starting cationic polymerization of a thermosetting resin (for example, thermosetting epoxy resin) in cooperation with an aluminum chelating agent. Therefore, the effect of promoting the curing of the epoxy resin can be obtained by using such a silane compound together. Examples of such silane compounds include highly sterically hindered silanol compounds and silane coupling agents having 1 to 3 lower alkoxy groups in the molecule. In the silane coupling agent molecule, a group having reactivity to the functional group of the thermosetting resin, for example, vinyl group, styryl group, acryloyloxy group, methacryloyloxy group, epoxy group, amino group, mercapto group However, since the latent curing agent of the present invention is a cationic curing agent, the amino group or the mercapto group substantially generates the generated cationic species. Can be used when not captured.

  When a highly sterically hindered silanol compound is used as the silane compound, if the amount of the highly sterically hindered silanol compound in the aluminum chelate latent curing agent of the present invention is too small, it will be insufficiently cured, and if too large, it will be cured. Since the later resin characteristics deteriorate, the silanol compound is preferably 1 to 50 parts by mass, more preferably 1 to 30 parts by mass with respect to 100 parts by mass of the thermosetting epoxy resin.

  Unlike the conventional silane coupling agent having a trialkoxy group, the highly sterically hindered silanol compound used in the thermosetting epoxy resin composition of the present invention has a chemical structure of the following formula (A): Arylsilaneol.

  In the formula, m is 2 or 3, preferably 3, provided that the sum of m and n is 4. Therefore, the silanol compound of the formula (A) becomes a mono or diol form. “Ar” is an aryl group which may be substituted, and examples of the aryl group include a phenyl group, a naphthyl group (for example, 1 or 2-naphthyl group), an anthracenyl group (for example, 1, 2, or 9-anthracenyl group). Benz [a] -9-anthracenyl group), phenaryl group (eg 3 or 9-phenaryl group), pyrenyl group (eg 1-pyrenyl group), azulenyl group, fluorenyl group, biphenyl group (eg 2,3 Or 4-biphenyl group), thienyl group, furyl group, pyrrolyl group, imidazolyl group, pyridyl group, and the like. Of these, a phenyl group is preferable from the viewpoint of availability and cost. The m Ars may be the same or different, but are preferably the same from the viewpoint of availability.

  These aryl groups can have 1 to 3 substituents, such as halogen such as chloro and bromo; trifluoromethyl; nitro; sulfo; carboxyl; alkoxycarbonyl such as methoxycarbonyl and ethoxycarbonyl; Electron-withdrawing groups; alkyl such as methyl, ethyl and propyl; alkoxy such as methoxy and ethoxy; hydroxy; amino; monoalkylamino such as monomethylamino; and electron-donating groups such as dialkylamino such as dimethylamino. In addition, the acidity of the hydroxyl group of silanol can be increased by using an electron withdrawing group as a substituent, and conversely, the acidity can be lowered by using an electron donating group, so that the curing activity can be controlled. Become. Here, the substituents may be different for each of the m Ars, but the substituents are preferably the same for the m Ars from the viewpoint of availability. Further, only some Ar may have a substituent, and other Ar may not have a substituent. Specific examples of the phenyl group having a substituent include 2, 3, or 4-methylphenyl group; 2,6-dimethyl, 3,5-dimethyl, 2,4-dimethyl, 2,3-dimethyl, 2,5- Examples include dimethyl or 3,4-dimethylphenyl group; 2,4,6-trimethylphenyl group; 2 or 4-ethylphenyl group.

  Among the silanol compounds of the formula (A), preferred are triphenylsilanol and diphenylsilanediol. Particularly preferred is triphenylsilanol.

  On the other hand, when a silane coupling agent having 1 to 3 lower alkoxy groups in the molecule is used as the silane compound, the amount of the silane coupling agent in the aluminum chelate latent curing agent of the present invention is too small. The addition effect cannot be expected, and if it is too much, an influence of a polymerization termination reaction caused by a silanolate anion generated from the silane coupling agent occurs, so 1 to 300 parts by mass, preferably 100 parts by mass of the aluminum chelate-based latent curing agent Is 1 to 100 parts by mass.

  Specific examples of the silane coupling agent that can be used in the thermosetting epoxy resin composition of the present invention include vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-styryltrimethoxysilane, γ -Methacryloxypropyltrimethoxysilane, γ-acryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldi Ethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ -Aminopropyltrimeth Shishiran, .gamma.-mercaptopropyltrimethoxysilane, mention may be made of .gamma.-chloropropyl trimethoxysilane.

  The thus obtained thermosetting epoxy resin composition of the present invention is additionally filled with an aluminum chelating agent as a curing agent, and is subjected to a surface activity suppression treatment by forming an alumina coating on the surface. It uses an aluminum chelate-based latent curing agent with improved properties, so it has excellent solvent resistance and excellent storage stability despite being a one-part type containing an organic solvent such as PGMEA. . In addition, although it contains a glycidyl ether epoxy resin that could not be sufficiently cured with an aluminum chelate-based latent curing agent, a highly sterically hindered silanol compound is a cationic polymerization catalyst in the epoxy resin. Since it is contained without impairing the accelerating ability, the thermosetting epoxy resin composition can be cationically polymerized by low temperature rapid curing.

  The aluminum chelate-based latent curing agent of the present invention can further contain a filler such as silica and mica, a pigment, an antistatic agent and the like, if necessary.

  Hereinafter, the present invention will be specifically described.

Control Example <Step A: Particulate Curing Agent Preparation Step>
(Preparation of aqueous phase)
800 parts by mass of distilled water, 0.05 part by mass of a surfactant (Nurex RT, NOF Corporation), and 4 parts by mass of polyvinyl alcohol (PVA-205, Kuraray Co., Ltd.) as a dispersant. Into a 3 liter interfacial polymerization vessel equipped with a thermometer, the mixture was uniformly mixed to prepare an aqueous phase.

(Preparation of oil phase)
Next, 80 parts by mass of a 24% isopropanol solution of aluminum monoacetylacetonate bis (ethylacetoacetate) (aluminum chelate D, Kawaken Fine Chemical Co., Ltd.) and methylenediphenyl-4,4′-diisocyanate as a polyfunctional isocyanate compound 80 parts by mass of (3 mol) of trimethylolpropane (1 mol) adduct (D-109, Mitsui Chemicals, Inc.) and 80 parts by mass of triphenylsilanol (Tokyo Chemical Industry Co., Ltd.) An oil phase dissolved in parts by mass was prepared.

(Interfacial polymerization)
The prepared oil phase is put into the previously prepared aqueous phase, and after emulsifying and mixing with a homogenizer (1000 rpm / 5 minutes: T-50, IKA Japan Co., Ltd.), the interface is stirred at 70 ° C. for 6 hours at 200 rpm. Polymerization was performed. After completion of the reaction, the polymerization reaction solution is allowed to cool to room temperature, and the generated interfacially polymerized resin particles are filtered off, washed by filtration with distilled water, and air-dried at room temperature for surface activity suppression treatment. No bulky curing agent was obtained. The bulk curing agent was pulverized into primary particles using a pulverizer (A-O jet mill, Seisin Corporation) to obtain a particulate curing agent.

<Process B: Aluminum chelating agent additional filling process>
15 parts by mass of the particulate curing agent obtained in Step A was mixed with 12.5 parts by mass of an aluminum chelating agent (Aluminum Chelate D, Kawaken Fine Chemical Co., Ltd.) and another aluminum chelating agent (ALCH-TR, Kawaken Fine Chemical ( Co.) 25 parts by mass was put into an aluminum chelate solution dissolved in 62.5 parts by mass of ethyl acetate, and stirred at 80 ° C. for 9 hours at a stirring speed of 200 rpm while volatilizing ethyl acetate. After the stirring, the mixture was filtered and washed with cyclohexane to obtain a bulky curing agent. This bulk curing agent is vacuum-dried at 30 ° C. for 4 hours, and then pulverized into primary particles using a pulverizer (A-O jet mill, Seishin Enterprise Co., Ltd.). 11 parts by weight of a particulate curing agent was obtained. The amount of ethyl acetate in the filtrate was the amount from which the original 95% by mass was removed.

  In this step, the reason why the acquisition amount of the particulate curing agent was reduced from 11 parts by mass and 15 parts by mass of the charged amount was considered that triphenylsilanol in the curing agent was eluted into ethyl acetate. It is done. As a result, it is considered that the portion where triphenylsilanol in the curing agent has eluted (that is, the portion capable of holding the aluminum chelating agent) increases, and the aluminum chelating agent is additionally filled therein.

Examples 1 and 2
The system particulate curing agent additionally filled with an aluminum chelating agent obtained by repeating Step A and Step B of the control example was added to Step C below.

<Process C: Surface activity suppression treatment process>
20 parts by mass of the particulate curing agent additionally filled with an aluminum chelating agent obtained in Step B was used as an alumina sol (F-1000, Kawasaki), a 5% colloidal aqueous solution of boehmite alumina fibers having an average fiber length of 1400 nm and an average fiber width of 4 nm. The mixture was added to 180 parts of Ken Fine Chemical Co., Ltd. and stirred at 30 ° C. for 6 hours at 200 rpm. After the stirring, the mixture was centrifuged while washing with distilled water, and vacuum-dried at 30 ° C. (Example 1) or 60 ° C. (Example 2) for 4 hours to obtain a bulky curing agent. This bulk curing agent is pulverized into primary particles using a pulverizer (A-O jet mill, Seishin Enterprise Co., Ltd.), so that an aluminum chelating agent is additionally filled and surface activity is suppressed by forming an alumina coating. The obtained aluminum chelate-based latent curing agent was obtained.

Comparative Examples 1 and 2
The system particulate curing agent additionally filled with an aluminum chelating agent obtained by repeating Step A and Step B of the control example was added to Step C below.

<Process C: Surface activity suppression treatment process>
20 parts by mass of a particulate curing agent additionally filled with an aluminum chelating agent obtained in Step B was used as an ethylene-acrylic acid (EAA) copolymer emulsion (Bettersol, Seishin Enterprise Co., Ltd.) having a resin content of 20% by mass. It put into 180 mass parts and stirred at 200 rpm for 6 hours at 30 degreeC. After completion of stirring, the mixture was centrifuged while being washed with distilled water, and vacuum-dried at 30 ° C. (Comparative Example 1) or 60 ° C. (Comparative Example 2) for 4 hours to obtain a bulky curing agent. This bulk curing agent is crushed into primary particles using a crushing apparatus (A-O jet mill, Seishin Enterprise Co., Ltd.), so that an aluminum chelating agent is additionally filled and the surface is formed by forming an EAA copolymer film. An aluminum chelate-based latent curing agent subjected to activity suppression treatment was obtained.

(Differential scanning calorimetry (DSC) of particulate curing agent)
4 parts by mass of the particulate curing agent of Comparative Example, Examples 1-2 and Comparative Examples 1-2, 80 parts by mass of bisphenol A type epoxy resin (EP828, Mitsubishi Chemical Corporation) and triphenylsilanol (Tokyo Chemical Industry Co., Ltd.) )) A thermosetting epoxy resin composition for DSC measurement was obtained by uniformly mixing 8 parts by mass.

  This thermosetting epoxy resin composition was subjected to thermal analysis (DSC) using a differential scanning calorimeter (DSC6200, Hitachi High-Tech Science Co., Ltd.) with an evaluation amount of 5 mg and a heating rate of 10 ° C./min. The obtained results are shown in Table 1, and the DSC chart is shown in FIG.

  As can be seen from Table 1 and FIG. 1, the thermosetting epoxy resin composition using the aluminum chelate-based latent curing agent on which the alumina coating of Examples 1 and 2 was formed uses the particulate curing agent of the control example. Compared with the thermosetting epoxy resin composition, the exothermic peak temperature was shifted to the high temperature side, but since the alumina coating is porous, the exothermic start temperature is in the range of 98 to 105 ° C., and the heat responsiveness Was maintained. In addition, since the low temperature activity increases when the vacuum drying temperature of the aluminum chelate detergent hardener increases from 30 ° C. (Example 1) to 60 ° C. (Example 2), the heat generation start temperature and the heat generation peak temperature are on the low temperature side. Shifted.

  In contrast, the thermosetting epoxy resin composition using the aluminum chelate-based latent curing agent on which the EAA copolymer film of Comparative Examples 1 and 2 was formed is due to the influence of acid residues derived from acrylic acid, Compared with the control example, the heat generation start temperature was lowered, and the heat resistance improvement effect due to film formation was not obtained.

(Solvent resistance)
6 parts by mass of the particulate curing agent of Examples 1-2 and Comparative Examples 1-2, 60 parts by mass of bisphenol A type epoxy resin (EP828, Mitsubishi Chemical Corporation), triphenylsilanol (Tokyo Chemical Industry Co., Ltd.) 6 A thermosetting epoxy resin composition for evaluating solvent resistance was obtained by uniformly mixing 40 parts by mass of propylene glycol monomethyl ether acetate (PGMEA).

  The obtained thermosetting epoxy resin composition was allowed to stand at room temperature (aging), and after a predetermined time elapsed, a viscosity of 20 ° C. was used using a vibration viscometer (SV-10, A & D Co., Ltd.). Was measured. Table 2 shows the obtained results.

  From the results in Table 2, the viscosity change of the thermosetting epoxy resin composition using the aluminum chelate-based latent curing agent of Examples 1 and 2 on which an alumina coating was formed was substantially observed even after 4 hours. Was not.

  On the other hand, the thermosetting epoxy resin composition using the aluminum chelate-based latent curing agent of Comparative Examples 1 and 2 in which an ethylene-acrylic acid copolymer film was formed was 12 to 13% after 4 hours. An increase in viscosity was observed.

(Electron microscope observation)
An electron micrograph of the aluminum chelate-based latent curing agent of Example 2 was obtained using a scanning electron microscope (JSM-6510A, JEOL Ltd.). FIG. 2 shows a SEM photograph of 5000 times and FIG. 3 of a 15000 times. From these photographs, it can be seen that a good particle state free from foreign matters and aggregates is maintained even after the surface activity suppression treatment.

Comparative Example 3
Instead of 80 parts by mass of alumina sol (F-1000, Kawaken Fine Chemical Co., Ltd.), a 5% colloidal aqueous solution of boehmite alumina fibers having an average fiber length of 1400 nm and an average fiber width of 4 nm, an average fiber length of 3000 nm and an average fiber width of 4 nm By repeating Example 1 except that alumina sol (F-3000, Kawaken Fine Chemical Co., Ltd.), which is a 5% colloidal aqueous solution of boehmite alumina fiber, is used, an aluminum chelating agent is additionally filled and the surface is formed by forming an alumina coating. An aluminum chelate-based latent curing agent subjected to activity suppression treatment was obtained. The resulting aluminum chelate-based latent curing agent became a gel-like aggregate, probably because the condensation reaction between the boehmite alumina fibers was prioritized over the aluminum chelate-based latent curing agent of Example 1 or 2.

  Since the aluminum chelate-based latent curing agent of the present invention is additionally filled with an aluminum chelating agent and is subjected to surface activity suppression treatment, it exhibits excellent low-temperature rapid curing properties, one-part storage stability, and solvent resistance. . In particular, it can be applied to epoxy compounds that require solvent resistance. Moreover, although it is excellent in low-temperature rapid-curing property as a cationic curing catalyst, it is excellent in liquid life with one liquid in the presence of an alicyclic epoxy compound. Since a large amount of the aluminum chelating agent can be held inside the curing agent, the amount added to the resin composition to be cured can be reduced. Therefore, it is useful as a curing agent for a thermosetting epoxy resin composition.

Claims (17)

The aluminum chelating agent is a method for producing an aluminum chelate-based latent curing agent held in a porous resin obtained by interfacial polymerization of a polyfunctional isocyanate compound, and the following steps (A) to (C)
(Process A: Particulate curing agent preparation process)
An oil phase obtained by dissolving or dispersing an aluminum chelating agent and a polyfunctional isocyanate compound in a volatile organic solvent is subjected to interfacial polymerization of the polyfunctional isocyanate compound by stirring while heating in an aqueous phase containing the dispersant. A step of preparing a particulate curing agent by holding an aluminum chelating agent in the porous resin obtained thereby;
(Process B: Aluminum chelating agent additional filling process)
The particulate curing agent obtained in step A is dispersed and mixed in an aluminum chelating agent solution in which an aluminum chelating agent is dissolved in a volatile organic solvent, and the volatile organic solvent is removed while stirring the obtained dispersion mixture. A step of additionally filling an aluminum chelating agent into the particulate curing agent; and (step C: surface activity suppression treatment step)
An alumina coating is formed on the surface of the particulate curing agent additionally filled with the aluminum chelating agent, and the surface activity of the particulate curing agent is suppressed, thereby obtaining a latent aluminum chelate-based latent curing agent. The manufacturing method characterized by having a process.   2. The production method according to claim 1, wherein the surface activity suppressing treatment in Step C is stirring the particulate curing agent in a hydrous alumina sol dispersion.   The production method according to claim 2, wherein the hydrous alumina sol dispersion is obtained by mixing 30 to 99 parts by mass of a hydrous medium with 1 to 70 parts by mass of alumina sol.   The method according to claim 3, wherein the alumina sol is obtained by dispersing alumina fibers having an average fiber length of 1 to 10,000 nm and an aspect ratio (average fiber length / average fiber width) of 30 to 5000 in a water-containing medium.   The production method according to claim 3 or 4, wherein the alumina fiber content in the alumina sol is 1 to 30% by mass.   The production method according to any one of claims 1 to 5, wherein a silane compound is mixed in the oil phase in step A.   The production method according to claim 6, wherein the silane compound is triphenylsilanol.   The method according to any one of claims 1 to 7, wherein the removal of the volatile organic solvent in the step B is performed by heating the dispersion mixture to the boiling point of the volatile organic solvent or higher.   The manufacturing method in any one of Claims 1-8 by which the radically polymerizable compound and the radical polymerization initiator are mix | blended with the oil phase in the process A.   The manufacturing method of Claim 9 in which a radically polymerizable compound contains a polyfunctional radically polymerizable compound.   The manufacturing method of Claim 10 in which a radically polymerizable compound contains a polyfunctional radically polymerizable compound at least 50 mass% or more.   The method according to claim 10 or 11, wherein the polyfunctional radically polymerizable compound is a polyfunctional vinyl compound.   The production method according to claim 12, wherein the polyfunctional vinyl compound is divinylbenzene.   The manufacturing method in any one of Claims 10-13 in which a polyfunctional radically polymerizable compound contains a polyfunctional (meth) acrylate type compound further.   The production method according to any one of claims 1 to 14, wherein the content of the aluminum chelating agent in the oil phase in Step A is 10 to 500 parts by mass with respect to 100 parts by mass of the polyfunctional isocyanate compound.   The thermosetting epoxy resin composition containing the aluminum chelate type | system | group latent hardening | curing agent manufactured by the manufacturing method in any one of Claims 1-15, an epoxy resin, and a silane type compound.   The thermosetting epoxy resin composition according to claim 16, wherein the silane compound is triphenylsilanol.