JP2021038314A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition capable of achieving both low-temperature curing and enhancing stability during heating. An epoxy resin composition containing an epoxy resin (A), a thiol curing agent (B), and a curing accelerator (C), wherein the hard (C) is a compound of formula (1) and an epoxy. An epoxy resin composition containing a reaction product with a resin. (R1 and R2 are independently alkyl groups having 1 or more and 8 or less carbon atoms, cycloalkyl groups having 4 or more and 10 or less carbon atoms, or benzyl groups, and X and Z are independently hydrogen atoms and having 1 or more carbon atoms. It is an alkyl group of 8 or less, an aryl group, a cycloalkyl group having 4 or more and 10 or less carbon atoms, or a benzyl group, and the alkyl group and the cycloalkyl group aryl group may be substituted. N is an integer of 0 or more and 8 or less. , M is an integer of 0 or more and 4 or less.) [Selection diagram] None

Description

The present invention relates to epoxy resin compositions.

Epoxy resins and epoxy resin compositions are used in a wide range of applications such as insulating materials for electronic devices and electrical and electronic parts, sealing materials, adhesives, and conductive materials. In particular, electronic devices have become more sophisticated, smaller, and thinner, and along with the miniaturization of semiconductor chips and higher density of circuits, the productivity has been greatly improved, and the portability and reliability of electronic devices in mobile applications. Is required to be improved.

In a so-called two-component epoxy resin composition (hereinafter, may be referred to as "two-component epoxy resin composition") in which two components of an epoxy resin and a curing agent are mixed and cured at the time of use, the epoxy is said. As a method of curing the resin composition, there is a method of using a liquid amine-based curing agent.

When a liquid amine-based curing agent is used in the two-component epoxy resin composition, it can be cured well at a low temperature. However, it is necessary to store the epoxy resin and the curing agent separately, and it is necessary to weigh them at the time of use and mix them quickly and uniformly. Further, once the epoxy resin and the curing agent are mixed, the usable time after that is limited, so that both cannot be mixed in a large amount in advance. Further, the conventionally known two-component epoxy resin composition can meet the requirements at a practical level in all aspects of ease of storage, handleability, compounding frequency (manufacturing efficiency), curability, and physical properties of the cured product. It is difficult and there is still room for improvement.

In order to satisfy these requirements, a one-component epoxy resin composition (hereinafter, may be referred to as "one-component epoxy resin composition") has been proposed. As one-pack type epoxy resin composition, for example, dicyandiamide, BF ₃ - amine complex, amine salt, a latent curing agent and modified imidazole compounds, one-component epoxy resin composition containing the epoxy resin. Such a one-component epoxy resin composition is excellent in storage stability. However, the one-component epoxy resin composition tends to be inferior in curability, or even if it is excellent in curability, it tends to be inferior in storage stability.

Further, as an amine-based curing agent used in the epoxy resin composition, a microcapsule-type curing agent in which a core containing an amine-based curing agent is coated with a specific shell has been proposed (see, for example, Patent Document 1). Further, in order to improve storage stability and enable low-temperature short-time curing, an epoxy resin composition in which a microcapsule type curing agent and a thiol curing agent are used in combination has also been proposed (see, for example, Patent Document 2). ..
The epoxy resin composition of Patent Document 1 is said to be able to obtain a cured product having excellent light transmission and less cracking. It is said that the epoxy resin composition of Patent Document 2 can be cured at a low temperature for a short time, and is further excellent in adhesive strength and pot life.

Japanese Unexamined Patent Publication No. 2016-130287 International Publication 2017/057019 Pamphlet

However, it is difficult to realize low-temperature curing with the epoxy resin composition described in Patent Document 1, and it cannot be used for bonding heat-sensitive electronic parts and the like.
Further, it is said that the epoxy resin composition described in Patent Document 2 can be cured at a low temperature, but the stability at the time of heating is poor, and the epoxy resin composition is heated in order to increase the fluidity. The viscosity cannot be reduced.

Therefore, an object of the present invention is to provide an epoxy resin composition capable of achieving both low-temperature curing and enhancing stability during heating.

As a result of intensive studies to solve the above problems, the present inventors have added a curing accelerator containing a reaction product of a predetermined amine compound and an epoxy resin to an epoxy resin composition containing an epoxy resin and a thiol curing agent. It has been found that the epoxy resin composition containing the epoxy resin composition can be cured at a low temperature and has high stability during heating, and has completed the present invention.

That is, the present invention is as follows.
[1]
An epoxy resin composition containing an epoxy resin (A), a thiol curing agent (B), and a curing accelerator (C).
An epoxy resin composition in which the curing accelerator (C) contains a reaction product of a compound represented by the formula (1) and an epoxy resin.
(In the formula (1), R ¹ and R ² are independently substituted alkyl groups having 1 or more and 8 or less carbon atoms, and optionally substituted cycloalkyl groups having 4 or more and 10 or less carbon atoms. A group or a optionally substituted benzyl group,
Each of X and Z is independently a hydrogen atom, an alkyl group having 1 or more and 8 or less carbon atoms which may be substituted, an aryl group which may be substituted, and 4 or more and 10 or less carbon atoms which may be substituted. Cycloalkyl group, or optionally substituted benzyl group,
n is an integer of 0 or more and 8 or less.
m is an integer of 0 or more and 4 or less. )
[2]
The curing accelerator (C) is a latent curing agent having a core-shell structure.
The epoxy resin composition according to [1].
[3]
The curing accelerator (C) contains an amine compound (D) different from the compound represented by the formula (1).
The epoxy resin composition according to [1] or [2].
[4]
The molecular weight of the amine compound (D) is
50 g / mol or more and 250 g / mol or less,
Containing at least one tertiary amino group,
The epoxy resin composition according to [3].
[5]
The content of the amine compound (D) is 5 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the reaction product of the compound represented by the formula (1) and the epoxy resin.
The epoxy resin composition according to [3] or [4].
[6]
The tertiary amine concentration is 0.01% by mass or more and 0.4% by mass or less.
The epoxy resin composition according to any one of [1] to [5].
[7]
The thiol curing agent (B) contains a primary thiol.
The epoxy resin composition according to any one of [1] to [6].

According to the present invention, it is possible to provide an epoxy resin composition capable of achieving both low-temperature curing and enhancing stability during heating.

Hereinafter, a mode for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present embodiment is an example for explaining the present invention, and the present invention is not intended to be limited to the following contents. The present invention can be implemented with various modifications within the scope of the gist thereof.

[Epoxy resin composition]
The epoxy resin composition of the present embodiment contains an epoxy resin (A), a thiol curing agent (B), and a curing accelerator (C).
Further, the curing accelerator (C) contained in the epoxy resin composition of the present embodiment contains a reaction product of the compound represented by the formula (1) and the epoxy resin.

(In the formula (1), R ¹ and R ² are independently substituted alkyl groups having 1 or more and 8 or less carbon atoms, and optionally substituted cycloalkyl groups having 4 or more and 10 or less carbon atoms. A group or a optionally substituted benzyl group,
Each of X and Z is independently a hydrogen atom, an alkyl group having 1 or more and 8 or less carbon atoms which may be substituted, an aryl group which may be substituted, and 4 or more and 10 or less carbon atoms which may be substituted. Cycloalkyl group, or optionally substituted benzyl group,
n is an integer of 0 or more and 8 or less.
m is an integer of 0 or more and 4 or less. )

By providing the above-mentioned structure, the epoxy resin composition of the present embodiment can be cured at a low temperature and is excellent in stability at the time of heating. This factor can be considered as follows, but the factor is not limited to this.
The curing accelerator having a reaction product of the compound represented by the formula (1) and an epoxy resin has a large temperature dependence of solubility in an epoxy resin composition containing an epoxy resin and a thiol curing agent. When the heating temperature is low, the curing accelerator does not dissolve in the resin composition, so that the stability during heating is excellent. Further, when the heating temperature becomes high, the curing accelerator dissolves in the resin composition and cures in a short time.

(Epoxy resin (A))
The epoxy resin composition of the present embodiment contains an epoxy resin. In this specification, the epoxy resin is also referred to as the epoxy resin (A). The epoxy resin (A) is not limited to the following as long as the effects of the present invention can be exhibited, but for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, tetrabromo bisphenol A Type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, tetrabromobiphenyl type epoxy resin, diphenyl ether type epoxy resin, benzophenone type epoxy resin, phenylbenzoate type epoxy resin, diphenyl sulfide type epoxy resin, diphenyl sulfoxide type epoxy resin , Diphenylsulfone type epoxy resin, diphenyldisulfide type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, hydroquinone type epoxy resin, methylhydroquinone type epoxy resin, dibutylhydroquinone type epoxy resin, resorcin type epoxy resin, methylresorcin type epoxy resin , Catecol type epoxy resin, bifunctional epoxy resin such as N, N-diglycidyl aniline type epoxy resin; N, N-diglycidyl aminobenzene type epoxy resin, o- (N, N-diglycidyl amino) toluene type Trifunctional epoxy resins such as epoxy resins and triazine epoxy resins; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane epoxy resins and diaminobenzene epoxy resins; phenol novolac epoxy resins, cresol novolac epoxy resins, Polyfunctional epoxy resins such as triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, dicyclopentadiene type epoxy resin, naphthol aralkyl type epoxy resin, bromoized phenol novolac type epoxy resin; and alicyclic epoxy resin , Epoxy resins obtained by modifying these epoxy resins with isocyanate or the like.
These epoxy resins may be used alone or in combination of two or more.

(Thiol hardener (B))
The epoxy resin composition of the present embodiment contains a thiol curing agent. In the present specification, the thiol curing agent is also referred to as a thiol curing agent (B). The thiol curing agent (B) is a thiol compound having two or more thiol groups in the molecule.
The thiol curing agent is not particularly limited, and for example, trimethyl propanthris (thioglycolate), pentaerythritol tetrakis (thioglycolate), ethylene glycol dithioglycolate, trimethyl propanthris (β-thiopropionate), and the like. Pentaerythritol A thiol compound obtained by an esterification reaction of a polyol such as tetrakis (β-thiopropionate) or dipentaerythritol poly (β-thiopropionate) with a thiol organic acid; 1,4-butanedithiol, 1 , 6-Hexandithiols, 1,10-decandithiols and other alkyl polythiol compounds, terminal thiol group-containing polyethers, terminal thiol group-containing polythioethers, thiol compounds obtained by the reaction of epoxy compounds with hydrogen sulfide; A thiol compound having a terminal thiol group obtained by the above reaction; and the like.
Specific examples of the thiol curing agent (B) include pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexasis (3-mercaptopropionate), and trimethylolpropane tris (3-mercaptopropionate). Nate) and the like.
These curing agents may be used alone or in combination of two or more.
Among the thiol curing agents (B), primary thiols are preferable from the viewpoint of quick curing at low temperatures.

(Curing accelerator (C))
The epoxy resin composition of the present embodiment further contains a curing accelerator.
The curing accelerator contains a reaction product of an epoxy resin and a compound represented by the following formula (1). The reaction product preferably contains an amine adduct having an amino group.

In the formula (1), R ¹ and R ² are independently substituted alkyl groups having 1 or more and 8 or less carbon atoms, and optionally substituted cycloalkyl groups having 4 or more and 10 or less carbon atoms. A group or a optionally substituted benzyl group,
Each of X and Z is independently a hydrogen atom, an alkyl group having 1 or more and 8 or less carbon atoms which may be substituted, an aryl group which may be substituted, and 4 or more and 10 or less carbon atoms which may be substituted. Cycloalkyl group, or optionally substituted benzyl group,
n is an integer of 0 or more and 8 or less.
m is an integer of 0 or more and 4 or less.

^{Examples of the alkyl group having 1 to 8 carbon atoms which may be substituted in R 1} and R ² in the formula (1) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and a cyclopropyl group. n-Butyl group, sec-butyl group, tert-butyl group, isobutyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group. Group etc. can be mentioned.

^{Examples of the cycloalkyl group having 4 or more and 10 or less carbon atoms which may be substituted in R 1} and R ² in the formula (1) include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like. Can be mentioned.

The alkyl group having 1 to 8 carbon atoms which may be substituted and the cycloalkyl group having 4 to 10 carbon atoms which may be substituted in X and Z in the formula (1) are R. ^{Examples of 1} and R ² include alkyl groups having 1 to 8 carbon atoms which may be substituted and cycloalkyl groups having 4 to 10 carbon atoms which may be substituted, as in the examples.

Examples of the aryl group which may be substituted in X and Z in the formula (1) include a phenyl group, a tolyl group, an o-xylyl group and the like.

In the epoxy resin composition of the present embodiment, from the viewpoint of curability and physical properties of the cured product, the compounds represented by the formula (1) include N, N-dimethylaminopropylamine and N, N-diethylaminopropylamine. , N, N-dibutylaminopropylamine, N, N-dimethylaminoethylamine, N, N-diethylethylenediamine, N, N-diisopropylethylenediamine, N, N-dibutylethylenediamine, N, N-dimethylaminobutylamine, N, N -Dipropylaminopropylamine, N, N-diisopropylaminopropylamine, 4-amino-1-diethylaminopentane, N, N-dimethyl-methanediamine, N, N-bis (1-methylethyl) -1,3- It is preferably one or more selected from the group consisting of propanediamine, N, N-dimethyl-1,2-propanediamine, and N, N-dimethyl-1,1-propanediamine.

The amine adduct is a reaction product of an epoxy resin and a compound represented by the formula (1), and preferably has an amino group. Examples of the epoxy resin include the same as the above-mentioned example of the epoxy resin (A).
The method for producing the amine adduct is not particularly limited, and suitable conditions can be appropriately selected in consideration of the desired structure of the amine adduct and the like.

As the reaction conditions (method for producing amine adduct) of the epoxy resin and the compound represented by the formula (1), the reaction is carried out at a temperature of 50 to 250 ° C. for 0.1 to 10 hours in the presence of a solvent, if necessary. Is preferable.
Solvents include, but are not limited to, hydrocarbons such as benzene, toluene, xylene, cyclohexane, mineral spirit, and naphtha; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); ethyl acetate. , Esters such as acetate-n-butyl, propylene glycol monomethyl ether acetate; alcohols such as methanol, isopropanol, n-butanol, butyl cellosolve, butyl carbitol; water; and the like. These solvents may be used alone or in combination of two or more. After the reaction is completed, the solvent is preferably removed from the reaction system by distillation or the like.

The curing accelerator (C) is not limited to the following as long as the effect of the present invention can be exhibited, but from the viewpoint of stability during heating, a latent curing agent having a core-shell structure (hereinafter, "microcapsule type"). It is also referred to as "latent curing agent").

Here, it is preferable that the core of the microcapsule type latent curing agent contains an amine compound (D) different from the compound represented by the formula (1). The epoxy resin composition of the present embodiment has high low temperature curability by containing the amine compound (D).

As the amine compound (D), it is preferable to use a low molecular weight amine compound containing at least one tertiary amino group from the viewpoint of improving the effect promoting action of the thiol curing agent.
The molecular weight of the amine compound (D) is preferably 50 g / mol or more and 250 g / mol or less, more preferably 80 g / mol or more and 220 g / mol or less, and further preferably 100 g / mol or more and 180 g / mol or less. is there. When the molecular weight is 50 g / mol or more, stability during heating can be maintained, and when it is 250 g / mol or less, the reactivity can be further enhanced.

The amine compound (D) preferably has a molecular weight of 50 g / mol or more and 250 g / mol or less and contains at least one tertiary amino group from the viewpoint of improving the effect promoting action of the thiol curing agent.

The low molecular weight amine compound having a tertiary amino group is not limited to the following, and is, for example, trimethylamine, triethylamine, benzyldimethylamine, N, N-dimethyl-ethylamine, N, N-dimethyl-butylamine. , N, N-dimethyldecylamine, N, N-dimethyl-m-toluidine, N, N-dimethyl-p-toluidine, 2,6,10-trimethyl-2,6,10-triazaundecan, N, N '-Dimethylpiperazin, 1,4-diazabicyclo [2.2.2] octane, 1-azabicyclo [2.2.2] octane-3-one, 1,8-diazabicyclo (5,4,0) -undecene- Tertiary amines such as 7,1,5-diazabicyclo (4,3,0) -nonen-5, hexamethylenetetramine; 1-methylimidazole, 1,2-dimethylimidazole, 1-vinyl imidazole, 1-allyl imidazole , 2-Methyl-1-vinylimidazole, N-acetylimidazole and other imidazoles; dimethylaminobenzhydrol, bis [4- (dimethylamino) phenyl] methane, 4,4'-bis (dimethylamino) benzophenone, 2 Aromatic tertiary amines such as −diethylamino-N- (2,6-dimethylphenyl) acetamide; aminopyridines having a tertiary amino group such as 2-dimethylaminopyridine and 4-dimethylaminopyridine can be mentioned. These amine compounds may be used alone or in combination of two or more.

The concentration of the amine compound (D) is preferably 2 wt% or more and 20 wt% or less, more preferably 3 wt% or more and 15 wt% or less, and further preferably 5 wt% or more and 13 wt% or less in the curing accelerator (C). The amine compound (D) is preferably contained in the core of the microcapsule type latent curing agent, and the ratio of the amine compound (D) in the core is 2 wt% or more and 20 wt% or less, thereby adding curability. It tends to be compatible with warm stability.

From the viewpoint of stability during heating and low-temperature curability, the tertiary amine concentration in the epoxy resin composition is preferably 0.01% by mass or more and 0.4% by mass or less, and more preferably 0.015% by mass or more. It is 0.38% by mass or less, more preferably 0.04% by mass or more and 0.37% by mass or less. The concentration of the tertiary amine can be measured by the method described in Examples.

The average particle size of the core of the microcapsule type latent curing agent is preferably more than 0.3 μm and 12 μm or less. When the average particle size of the core of the microcapsule type latent curing agent exceeds 0.3 μm, the aggregation of the microcapsule type latent curing agents can be further prevented, and the formation of the microcapsule type latent curing agent becomes easier. , The storage stability of the epoxy resin composition tends to be obtained. When the average particle size of the core of the microcapsule type latent curing agent is 12 μm or less, a homogeneous cured product tends to be obtained. Further, since the average particle size of the core of the microcapsule type latent curing agent is 12 μm or less, a diluent, a filler, a pigment, a dye, a flow conditioner, a thickener, a strengthening agent, a mold release agent, and a wetting agent are used. , Stabilizers, flame retardants, surfactants, organic solvents, conductive fine particles, crystalline alcohols, other resins, etc. can prevent the formation of large particle size agglomerates, and the cured product can be used for a sufficiently long period of time. It tends to be reliable.

The average particle size referred to here means an average particle size defined by the median diameter. More specifically, the average particle size refers to the Stokes diameter measured by a laser diffraction / light scattering method using a particle size distribution meter (“HORIBA LA-920” manufactured by HORIBA, Ltd.).

The method for controlling the average particle size of the core is not particularly limited, and for example, a method for precisely controlling the core crushing step of the massive microcapsule type latent curing agent, a method for controlling the massive microcapsule type latent curing agent, A method of performing a coarse crushing step and a fine crushing step as a crushing step of the core of the above, and further classifying and obtaining a solution having a desired average particle size using a precision classification device, a core of a massive microcapsule type latent curing agent. Examples thereof include a method of spray-drying a core solution of a microcapsule type latent curing agent in which the above-mentioned substance is dissolved in a solvent.

The apparatus used for pulverization is not particularly limited, and for example, a ball mill, an attritor, a bead mill, a jet mill and the like can be adopted as needed, and it is preferable to use an impact pulverizer. Examples of the impact type crusher include jet mills such as a swirl type flow powder collision type jet mill and a powder collision type counter jet mill. A jet mill is a device that collides solid materials with each other to form fine particles by a high-speed jet flow using air or the like as a medium.

The precise control method of pulverization is not particularly limited, and examples thereof include a method of controlling temperature, humidity, pulverization amount per unit time, and the like at the time of pulverization.

The method for precisely classifying the pulverized product is not particularly limited. For example, after pulverization, a sieve (for example, a standard sieve such as 325 mesh or 250 mesh) is used to obtain powder particles having a predetermined average particle size by classification. And a method of classifying using a classifier, a method of classifying by wind power according to the specific gravity of particles, and the like. The classifier to be used is not particularly limited, and examples thereof include a wet classifier and a dry classifier, but a dry classifier is generally preferable. Examples of dry classifiers include "Elbow Jet" manufactured by Nittetsu Mining Co., Ltd., "Fine Sharp Separator" manufactured by Hosokawa Micron Co., Ltd., "Variable Impactor" manufactured by Sankyo Electric Co., Ltd., and "Spedic Classifier" manufactured by Seishin Enterprise Co., Ltd. "Donna Celec" manufactured by Donaldson Japan, "YM Microcassette" manufactured by Yasukawa Shoji, "Turbo Classifier" manufactured by Nisshin Engineering, and other dry classifiers such as various air separators, micron separators, microbrex, and AccuCut. Etc., but are not limited to these.

The method of directly granulating the particles instead of pulverization is not particularly limited, and for example, a core solution of the microcapsule type latent curing agent in which the core of the massive microcapsule type latent curing agent is dissolved in a solvent is used. A method of spray drying can be mentioned. Specific examples of the method for directly granulating the particles include a method in which the core is uniformly dissolved in an appropriate organic solvent, sprayed as fine droplets in a solution state, and then dried with hot air or the like. The drying device in this case is not particularly limited, and examples thereof include a normal spray drying device. Further, although not particularly limited, for example, after the core is uniformly dissolved in an appropriate organic solvent, the core is precipitated in the form of fine particles by adding a poor solvent for the core while stirring the uniform solution strongly. After the particles are separated by filtration, the solvent can be dried and removed at a low temperature equal to or lower than the melting point of the core to obtain a core having a desired particle size range.

The method of adjusting the average particle size of the core in the particle state by a method other than classification is not particularly limited, and for example, a method of adjusting the average particle size by mixing a plurality of particles having different average particle sizes. And so on. Further, for example, in the case of a core of a microcapsule type latent curing agent having a large particle size that is difficult to grind or classify, another core of a microcapsule type latent curing agent having a small particle size is added and mixed. Therefore, it can also be used as a core of a microcapsule type latent curing agent having an average particle size in the above range. The core of the microcapsule type latent curing agent thus obtained may be further classified if necessary. The mixer used for the purpose of mixing such powders is not particularly limited, and for example, a container rotary mixer that rotates a container body containing the powder to be mixed, and a container body containing the powder are used. Examples thereof include a container fixed type mixer that mixes by mechanical stirring or air flow stirring without rotating, and a composite type mixer that rotates a container containing powder and mixes by using other external force.

The shape of the core may be, for example, spherical, granular, powdery, amorphous, or the like, and is not particularly limited. Among these, the shape of the core is preferably spherical from the viewpoint of reducing the viscosity of the epoxy resin composition. The term "spherical" includes not only a true sphere but also an amorphous shape with rounded corners.

The microcapsule-type latent curing agent preferably has a core having an average particle size of more than 0.3 μm and 12 μm or less, and a structure in which the surface of the core is coated with a shell containing a resin and / or an inorganic oxide. It is preferable that it is a thing. Among these, it is preferable that the shell contains a resin from the viewpoint of the stability of the film constituting the shell, the ease of breaking during heating, and the uniformity of the cured product.

The resin constituting the shell is not limited to the following, and examples thereof include epoxy resin, phenol resin, polyester resin, polyethylene resin, nylon resin, polystyrene resin, urethane resin and the like. .. Among these, the resin is preferably an epoxy resin, a phenol resin, or a urethane resin.

The epoxy resin constituting the shell is not limited to the following, but includes, for example, an epoxy resin having two or more epoxy groups, an epoxy resin having two or more epoxy groups, and a compound having two or more active hydrogens. Examples thereof include a reaction product of a resin produced by the above reaction and a compound having two or more epoxy groups and a compound having one active hydrogen and a carbon-carbon double bond. Among these, from the viewpoint of stability and low-temperature rapid curing, a resin produced by the reaction of a compound having two or more epoxy groups and a compound having two or more active hydrogens, particularly an amine-based curing agent and two or more. A reaction product with an epoxy resin having an epoxy group is preferable. Among these, a reaction product of an amine-based curing agent and an epoxy resin is preferable from the viewpoint of film stability and low-temperature quick-curing property. The epoxy resin constituting the shell may be an epoxy resin that reacts with the compound represented by the above-mentioned formula (1), and the same epoxy resin as that exemplified in the epoxy resin (A) is used. You can also do it.

The phenolic resin constituting the shell is not limited to the following, but for example, phenol / formaldehyde polycondensate, cresol / formaldehyde polycondensate, resorcinol / formaldehyde polycondensate, bisphenol A / formaldehyde polycondensate. , Polyethylene polyamine modified product of phenol / formaldehyde polycondensate, and the like.

The polyester-based resin constituting the shell is not limited to the following, but is, for example, ethylene glycol / terephthalic acid / polypropylene glycol polycondensate, ethylene glycol / butylene glycol / terephthalic acid polycondensate, terephthalic acid / ethylene. Examples thereof include glycol / polyethylene glycol polycondensate.

The polyethylene-based resin constituting the shell is not limited to the following, but is, for example, an ethylene / propylene / vinyl alcohol copolymer, an ethylene / vinyl acetate copolymer, or an ethylene / vinyl acetate / acrylic acid copolymer. And so on.

The nylon-based resin constituting the shell is not limited to the following, but is an adipic acid / hexamethylenediamine polycondensate, a sebacic acid / hexamethylenediamine polycondensate, and a p-phenylenediamine / terephthalic acid polycondensate. And so on.

The polystyrene-based resin constituting the shell is not limited to the following, but for example, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, acrylonitrile-styrene-divinylbenzene copolymer, styrene-. Examples thereof include propenyl alcohol copolymers.

The urethane-based resin constituting the shell is not limited to the following, but is, for example, butyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate, phenyl isocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone. Examples thereof include isocyanate monomers such as diisocyanate, trizine diisocyanate, naphthalenediocyanate, and triphenylmethane triisocyanate, condensates thereof, and polycondensates thereof with monoalcohol and polyhydric alcohol. Among these, a monoalcohol or a polyhydric alcohol and a urethane resin which is an addition product of the monoisocyanate or the polyisocyanate are preferable.

The inorganic oxide constituting the shell is not limited to the following, and examples thereof include boron compounds such as boron oxide and boric acid ester, silicon dioxide, and calcium oxide. Among these, boron oxide is preferable from the viewpoint of film stability and easiness of breaking during heating.

The shell constituting the microcapsule type latent curing agent is any two of an isocyanate compound, an active hydrogen compound, a compound represented by the formula (1), an epoxy resin (A), and an amine compound (D). It is preferable to include the above reaction products.

Examples of the active hydrogen compound include, but are not limited to, water, a compound having at least one primary amino group and / or a secondary amino group, a compound having at least one hydroxyl group, and the like. .. Further, the active hydrogen compound is used alone or in combination of two or more.

The compound having at least one primary amino group and / or secondary amino group is not particularly limited, and examples thereof include aliphatic amines, alicyclic amines, and aromatic amines.

The aliphatic amine is not limited to the following, but is, for example, an alkylamine such as methylamine, ethylamine, propylamine, butylamine and dibutylamine, and an alkylenediamine such as ethylenediamine, propylenediamine, butylenediamine and hexamethylenediamine. Polyalkylene polyamines such as diethylenetriamine, triethylenetetramine and tetraethylenepentamine; polyoxyalkylene polyamines such as polyoxypropylenediamine and polyoxyethylenediamine can be mentioned.

Examples of the alicyclic amine include, but are not limited to, cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, isophoronediamine and the like.

Examples of the aromatic amine include, but are not limited to, aniline, toluidine, benzylamine, naphthylamine, diaminodiphenylmethane, and diaminodiphenylsulfone.

The compound having at least one hydroxyl group is not particularly limited, and examples thereof include alcohol compounds and phenol compounds.

Alcohol compounds include, but are not limited to, methyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, and lauryl alcohol. , Dotesyl alcohol, stearyl alcohol, eikosyl alcohol, allyl alcohol, crotyl alcohol, propargyl alcohol, cyclopentanol, cyclohexanol, benzyl alcohol, cinnamyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol Monoalcohols such as monobutyl; ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-butanediol, 1,4-butanediol, hydrogenated bisphenol A, neopentyl glycol, glycerin, trimethylolpropane, penta Polyhydric alcohols such as erythritol; obtained by reacting a compound having at least one epoxy group with a compound having at least one hydroxyl group, carboxyl group, primary amino group, secondary amino group, or thiol group. Examples thereof include polyhydric alcohols such as compounds having two or more secondary hydroxyl groups in one molecule. These alcohol compounds may be primary alcohols, secondary alcohols, or tertiary alcohols.

The phenolic compound is not limited to the following, but is not limited to, for example, monophenols such as coalic acid, cresol, xylenol, carbachlor, motil, and naphthol, catechol, resorcin, hydroquinone, bisphenol A, bisphenol F, pyrogallol, and fluorochlorsin. , 2- (Dimethylaminomethyl) phenol, polyhydric phenols such as 2,4,6-tris (dimethylaminomethyl) phenol and the like.

The compound having at least one hydroxyl group is preferably a polyhydric alcohol or a polyhydric phenol, and more preferably a polyhydric alcohol, from the viewpoint of potential and solvent resistance.

It produces a reactant of any two or more of the above-mentioned isocyanate compound, active hydrogen compound, amine compound represented by the formula (1), epoxy resin (A), and low molecular weight amine compound (D). The reaction conditions are not particularly limited, but are usually 10 minutes or more and 12 hours or less in a temperature range of −10 ° C. or higher and 150 ° C. or lower.

When the isocyanate compound and the active hydrogen compound are used, the compounding ratio is preferably (isocyanate group in the isocyanate compound): (active hydrogen in the active hydrogen compound) (equivalent ratio), preferably 1: 0.1 to 1: 1000. Is the range of.

The reaction can be carried out in a predetermined dispersion medium, if necessary. The dispersion medium is not particularly limited, and examples thereof include solvents, plasticizers, resins, and the like. The solvent is not limited to the following, but for example, hydrocarbons such as benzene, toluene, xylene, cyclohexane, mineral spirit, and naphtha; ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK). Classes; esters such as ethyl acetate, -n-butyl acetate, propylene glycol monomethylethyl ether acetate; alcohols such as methanol, isopropanol, n-butanol, butyl cellosolve, butyl carbitol; water and the like. The plasticizer is not particularly limited, and is, for example, a phthalic acid diester-based plasticizer such as dibutyl phthalate and di (2-ethylhexyl) phthalate; an aliphatic dibasic acid ester-based plasticizer such as di (2-ethylhexyl) adipate. Plasticizers: Phthalic acid triester-based plasticizers such as tricresyl phosphate; Glycolester-based plasticizers such as polyethylene glycol esters and the like can be mentioned. The resins are not limited to the following, and examples thereof include silicone resins, epoxy resins, and phenol resins.

Among the above, the reaction between the epoxy resin and the epoxy resin curing agent is usually in the temperature range of −10 ° C. or higher and 150 ° C. or lower, preferably 0 ° C. or higher and 100 ° C. or lower, for 10 minutes or longer and 12 hours or shorter, preferably 30 minutes or longer. The reaction time is 8 hours or less. The dispersion medium is preferably a solvent or a plasticizer.
The proportion of the reaction product as described above in the shell is usually 1% by mass or more, preferably 50% by mass or more, and may be 100% by mass.

In the microcapsule type latent curing agent, the method for forming the shell covering the surface of the core is not particularly limited, and examples thereof include the following methods (1) to (3).
(1) After dissolving or dispersing the shell component and the core particles of the microcapsule type latent curing agent in the solvent which is the dispersion medium, the solubility of the shell component in the dispersion medium is lowered to microcapsule. A method of depositing a shell on the surface of particles in the core of a mold latent curing agent.
(2) A method in which particles of the core of a microcapsule type latent curing agent are dispersed in a dispersion medium, and the above-mentioned material for forming a shell is added to the dispersion medium to precipitate the particles of the curing agent for epoxy resin.
(3) A method in which the above-mentioned raw material component for forming a shell is added to a dispersion medium, and the surface of the particles of the core of the microcapsule type latent curing agent is used as a reaction field, and a shell forming material is produced there.
Here, the methods (2) and (3) are preferable because the reaction and the coating can be carried out at the same time.

Examples of the dispersion medium include solvents, plasticizers, resins and the like.
The solvent, plasticizer, and resin are not particularly limited, and for example, any two or more reactions of the above-mentioned isocyanate compound, active hydrogen compound, epoxy resin curing agent, epoxy resin, and amine compound, or more. Examples of solvents, plasticizers, and resins that can be used to obtain the product can be used.

The method for separating the microcapsule-type latent curing agent from the dispersion medium after forming the shell by the methods (2) and (3) above is not particularly limited, but the unreacted raw material after forming the shell is not particularly limited. , It is preferable to separate and remove it together with the dispersion medium. Examples of such a method include a method of removing the dispersion medium and the unreacted shell-forming material by filtration.
After removing the dispersion medium, it is preferable to wash the microcapsule type latent curing agent. Cleaning of the microcapsule latent curing agent can remove the material forming an unreacted shell adhering to the surface of the microcapsule latent curing agent.
The washing method is not particularly limited, but the residue by filtration can be washed with a solvent that does not dissolve the dispersion medium or the microcapsule type latent curing agent. By drying the microcapsule type latent curing agent after filtering and washing, the microcapsule type latent curing agent can be obtained in a powder form. The method of drying is not particularly limited, but it is preferable to dry at a temperature equal to or lower than the melting point of the microcapsule type latent curing agent or the softening point, and examples thereof include vacuum drying. By powdering the microcapsule type latent curing agent, the compounding work with the epoxy resin can be easily applied. Further, when an epoxy resin is used as the dispersion medium, a liquid resin composition containing the epoxy resin and the microcapsule type latent curing agent can be obtained at the same time as the shell is formed, which is preferable.

The shell formation reaction is usually carried out in a temperature range of −10 ° C. or higher and 150 ° C. or lower, preferably 0 ° C. or higher and 100 ° C. or lower, and a reaction time of 10 minutes or longer and 72 hours or shorter, preferably 30 minutes or longer and 24 hours or shorter. ..

Shell, from the viewpoint of balance between reactivity and storage stability, and urea bond group that absorbs infrared wave number 1630～1680Cm ^-1, and biuret bond group that absorbs infrared wave number 1680～1725Cm ^-1, wave number 1730 It is preferable to have a urethane bonding group that absorbs infrared rays of ~ 1755 cm ^-1. The urea-binding group, burette-binding group, and urethane-binding group can be measured using a Fourier transform infrared spectrophotometer (hereinafter, may be referred to as "FT-IR"). Further, it can be confirmed by microscopic FT-IR that the shell has a urea-binding group, a bullet-binding group, and a urethane-binding group. Specifically, the liquid epoxy resin composition of the present embodiment is cured with a modified aliphatic amine curing agent at 40 ° C. for 12 hours, and then the liquid epoxy resin is further cured at 120 ° C. for 24 hours. The composition is completely cured. Then, using an ultramicrotome, a sample having a thickness of 5 to 20 μm is prepared from the obtained cured product, and the depth direction of the shell is analyzed by FT-IR. By observing the vicinity of the surface of the shell, the presence of urea-binding groups, bullet-binding groups, and urethane-binding groups can be observed.

The thickness of the shell is preferably 5 nm or more and 1000 nm or less, and more preferably 10 nm or more and 100 nm or less. By setting the thickness of the shell to 5 nm or more, the storage stability of the epoxy resin composition of the present embodiment tends to be improved. By setting the thickness of the shell to 1000 nm or less, the curability tends to be improved. The thickness referred to here is an average layer thickness and can be measured with a transmission electron microscope.

The epoxy resin composition of the present embodiment may contain a stabilizer. By containing a stabilizer, the ratio (GT70 / GT80) of the gelation time at 70 ° C. (GT70) to the gelation time at 80 ° C. (GT80) tends to be controlled. The stabilizer is not particularly limited, but preferably contains one or more selected from the group consisting of a borate compound, a titanate compound, an aluminate compound, a zirconate compound, an isocyanate compound, a carboxylic acid, and an acid anhydride.

The borate compound is not particularly limited, but for example, trimethylborate, triethyl borate (triethyl borate), tripropyl borate, triisopropyl borate, tributyl borate (tributyl borate), tripentyl borate, triallyl borate, trihexyl borate. , Tricyclohexylborate, trioctylborate, trinonylborate, tridecylborate, tridodecylborate, trihexadecylborate, trioctadecylborate, tris (2-ethylhexyloxy) borate, bis (1,4,7,10- Tetraoxaundecyl) (1,4,7,10,13-pentaoxatetradecyl) (1,4,7-trioxaundecyl) borate, tribenzylborate, triphenylborate, tri-o-tolylborate, Examples thereof include trim-trilborate and triethanolamine borate.
Further, as the borate compound, a cyclic borate ester having a cyclic structure in the molecule can also be used. Examples of the cyclic borate include tris-o-phenylene bisborate, bis-o-phenylene pyroborate, bis-2,3-dimethylethylenephenylene pyroborate, bis-2,2-dimethyltrimethylene pyroborate and the like. ..
Examples of the cyclic borate ester include "Cure Duct" (registered trademark) L-01B (Shikoku Kasei Kogyo Co., Ltd.) and "Cure Duct" (registered trademark) L-07N (Shikoku Kasei Kogyo Co., Ltd.). Commercially available products can be used.

The titanate compound is not particularly limited, and examples thereof include tetraethyl titanate, tetrapropyl titanate, tetraisoproprutitanate, tetrabutyl titanate, and tetraoctyl titanate.

The aluminate compound is not particularly limited, and examples thereof include triethylaluminate, tripropylaluminate, triisopropylaluminate, tributylaluminate, and trioctylaluminate.

The zirconate compound is not particularly limited, and examples thereof include tetraethyl zirconate, tetrapropyl zirconate, tetraisopropyl zirconate, and tetrabutyl zirconate.

The isocyanate compound is not particularly limited, and is, for example, butyl isocyanate, isopropyl isocyanate, 2-chloroethyl isocyanate, phenyl isocyanate, p-chlorophenyl isocyanate, benzyl isocyanate, hexamethylene diisocyanate, 2-ethylphenyl isocyanate, 2,6-dimethyl. Phenylisocyanate, tolylene diisocyanate (eg 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate), 1,5-naphthalenedi isocyanate, diphenylmethane-4,4'-diisocyanate, trizine diisocyanate, isophorone diisocyanate, xylylene Examples thereof include isocyanate, paraphenylenediocyanate, and bicycloheptanetriisocyanate.

The carboxylic acid is not particularly limited, but for example, a saturated aliphatic monobasic acid such as formic acid, acetic acid, propionic acid, butyric acid, caproic acid and capric acid, and an unsaturated aliphatic monoacid such as acrylic acid, methacrylic acid and crotonic acid. Halogenized fatty acids such as basic acid, monochloroacetic acid and dichloroacetic acid, monobasic hydroxy acids such as glycolic acid, lactic acid and grape acid, aliphatic aldehyde acids such as glyoxylic acid and ketone acids, oxalic acids, malonic acids and succinic acids. Aliper polybasic acids such as maleic acid, benzoic acid halogenated benzoic acid, toluic acid, phenylacetic acid, cinnamic acid, mandelic acid and other aromatic monobasic acids, phthalic acid, trimesic acid and other aromatic polybasic acids, etc. Can be mentioned.

The acid anhydride is not particularly limited, and is, for example, an aliphatic such as succinic anhydride, dodecynyl succinic anhydride, maleic anhydride, additions of methylcyclopentadiene and maleic anhydride, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. Examples thereof include polybasic acid anhydrides; aromatic polybasic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyrrolimellitic anhydride.

In the epoxy resin composition of the present embodiment, the content of the epoxy resin (A) and the thiol curing agent (B) is not particularly limited, and the thiol curing agent (B) is relative to the epoxy equivalent of the epoxy resin (A). ) Is preferably 0.5 to 3.0 equivalents, more preferably 0.7 to 2.0 equivalents, and even more preferably 0.8 to 1.5 equivalents. ..

In the epoxy resin composition of the present embodiment, the content of the thiol curing agent (B) is preferably 30 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A), preferably 40 parts by mass. It is more preferably 150 parts by mass or less, and further preferably 55 parts by mass or more and 120 parts by mass or less.

In the epoxy resin composition of the present embodiment, the content of the curing accelerator (C) is preferably 0.1 part by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A). It is more preferably 1 part by mass or more and 70 parts by mass or less, and further preferably 1 part by mass or more and 60 parts by mass or less.

In the epoxy resin composition of the present embodiment, the content of the curing accelerator (C) is preferably 0.5 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the thiol curing agent (B). It is more preferably 5 parts by mass or more and 80 parts by mass or less, and further preferably 5 parts by mass or more and 50 parts by mass or less.

In the epoxy resin composition of the present embodiment, when the curing accelerator (C) contains an amine compound (D) different from the compound represented by the formula (1), the compound represented by the formula (1) and the epoxy resin The content of the amine compound (D) with respect to 100 parts by mass of the reaction product is preferably 5 parts by mass or more and 25 parts by mass or less, more preferably 7 parts by mass or more and 22 parts by mass or less, and 8 parts by mass or more and 17 parts by mass or less. More preferred. By setting the content of the amine compound (D) to 5 parts by mass or more, the curability tends to be further improved. By setting the content of the amine compound (D) to 25 parts by mass or less, the stability during heating tends to be further improved.

Hereinafter, the present embodiment will be described with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples. The measurement methods applied in Examples and Comparative Examples are shown below. In the following, unless otherwise specified, "parts" are based on mass.

(Content of tertiary amino group nitrogen in epoxy resin composition)
The content of tertiary amino group nitrogen in the epoxy resin composition was measured by a method based on JIS K7245: 2000.
Specifically, a sample solution was prepared in which the epoxy resin composition was dissolved in a mixed solution of toluene: 1-butanol = 1: 1. The appropriate amount of sample solution, with the required amount pre-calculated according to the sample, was precisely weighed into a 100 mL beaker to the order of 0.0001 g. 10 mL of acetic acid was added to the weighed sample solution so that the amino group nitrogen was 1 mmol and the titration amount was about 10 mL. Further, 10 mL of acetic anhydride was added, and the mixture was allowed to stand at room temperature for 15 to 30 minutes to amidate the primary and secondary amino groups. Further, 40 mL of acetic acid was added and set in a potentiometric titrator, and potentiometric titration was performed with a 0.1 mol / L perchloric acid / acetic acid solution to determine the titration amount at the end of the titration.
The content of tertiary amino group nitrogen can be calculated by the following formula.
Content of tertiary amino group nitrogen (wt%) = {0.014 × 0.1 × (v−v0) × f × 100} / W
W; Mass of amine adduct sample (g)
v; Titration (mL)
v0; Blank titration (mL)
f; Perchloric acid / acetic acid solution factor

(Low temperature curability)
When the epoxy resin compositions obtained in Examples and Comparative Examples were heated at 80 ° C., the time required until no tack was generated on the surface was measured.
◎ indicates that it was less than 5 minutes.
〇 indicates that it was 5 minutes or more and less than 30 minutes.
Δ indicates that it was 30 minutes or more and less than 60 minutes.
X indicates that it was 60 minutes or more.

(Stability when heated)
The viscosities of the epoxy resin compositions obtained in Examples and Comparative Examples before and after being stored in an oven heated to 40 ° C. for a predetermined time were measured using an E-type viscometer (25 ° C.).
The ratio of the viscosity of the epoxy resin composition after storage to the viscosity of the epoxy resin composition before storage (viscosity increase ratio) (= viscosity after storage / viscosity before storage) was calculated and evaluated.
When the viscosity exceeded the measurement limit, gelled, or hardened, the viscosity could not be measured, so it was marked as x.

[Production Example 1-1: Production of core (C-1) of microcapsule type latent curing agent]
To 738 g of a solution prepared by mixing 1-butanol and toluene at a ratio of 1/1 (mass ratio), 492 g of N, N-dimethylaminopropylamine (molecular weight 102 g / mol) as an amine compound was added, and the mixture was stirred to make a uniform solution. Was produced.
Next, 400 g of a bisphenol A type epoxy resin (Mitsubishi Chemical Corporation product "jER828") having an epoxy equivalent of 186 g / eq was added to 400 g of a solution prepared by mixing 1-butanol and toluene at a ratio of 1/1 (mass ratio). An epoxy resin solution was prepared by dissolving 1200 g of a bisphenol A type epoxy resin (Mitsubishi Chemical Co., Ltd. product "jER1055") having an epoxy equivalent of 815 g / eq.
An epoxy resin solution was added dropwise to the N, N-dimethylaminopropylamine solution at an internal temperature of 70 to 80 ° C. over 3 hours, and then the obtained reaction solution was heated at 100 ° C. for 2 hours. The molecular weight distribution was adjusted to obtain a block-shaped epoxy resin curing agent.
Next, the block-shaped epoxy resin curing agent was jet-milled to obtain a microencapsulated curing accelerator core (C-1) having an average particle size of 4.5 μm.

[Production Example 1-2: Production of core (C-2) of microcapsule type latent curing agent]
900 g of the block-shaped epoxy resin curing agent obtained in Production Example 1-1 is heated to 160 ° C., 110 g of DABCO (1,4-diazabicyclo [2.2.2] octane manufactured by Tokyo Kasei Co., Ltd., molecular weight 112 g / mol). ) Was stirred and mixed at 60 rpm at 160 ° C. for 1 hour and discharged from the flask to obtain a block-shaped epoxy resin curing agent.
Next, the obtained epoxy resin curing agent was jet-milled to obtain a microencapsulated curing agent core (C-2) having an average particle size of 3.0 μm.

[Production Example 1-3: Production of core (C-3) of microcapsule type latent curing agent]
N, N-dimethylaminopropylamine in Production Example 1-2 was 513 g of N, N-diethylaminopropylamine (molecular weight 130 g / mol), and DABCO was BDMA (manufactured by Tokyo Kasei Co., Ltd., N, N-dimethylbenzylamine, molecular weight 135 g). It was prepared in the same procedure as the microcapsule type latent curing agent core (C-2) except that it was changed to / mol), and the microcapsule type latent curing agent core (C-) having an average particle size of 4.5 μm was prepared. 3) was obtained.

[Production Example 1-4: Production of core (C-4) of microcapsule type latent curing agent]
N, N-dimethylaminopropylamine of Production Example 1-2 was added to 347 g of N, N-dimethylaminoethylamine (molecular weight 88 g / mol), and DABCO of Production Example 1-2 was added to DBU (manufactured by Tokyo Kasei Co., Ltd., 1,8-). It was prepared in the same procedure as the core (C-2) of the microcapsule type latent curing agent except that it was changed to diazabicyclo [5.4.0] -7-undecene, molecular weight 152 g / mol), and the average particle size was 4 A 0.0 μm microcapsule-type latent curing agent core (C-4) was obtained.

[Production Example 1-5: Production of core (C-5) of microcapsule type latent curing agent]
After dissolving 110 g of 2-ethyl-4-methylimidazole (molecular weight 110 g / mol) as an amine compound in a mixed solution of 100 g of xylene and 100 g of isopropyl alcohol, a bisphenol A type epoxy resin (Asahi Kasei) as an epoxy resin at 60 to 100 ° C. "AER2603" manufactured by E-Materials, epoxy equivalent 189, m) 189 g was added and reacted.
Then, by heating and reducing the pressure of the reaction solution, xylene and isopropyl alcohol, which are solvents, were distilled off from the reaction solution, and the content of unreacted 2-ethyl-4-methylimidazole was reduced to less than 0.01% by mass. I decided to stay until it became. After distilling off the solvent, the mixture is further heated to 160 ° C., and 34 g of DABCO (1,4-diazabicyclo [2.2.2] octane manufactured by Tokyo Kasei Co., Ltd.) is stirred and mixed at 60 rpm at 160 ° C. for 1 hour to obtain a flask. A block-shaped amine adduct mixture was obtained by dispensing from.
The amine adduct produced by the above procedure was pulverized in the same procedure as the core (C-1) of the microcapsule type latent curing agent to obtain a core (C-5) of the microcapsule type latent curing agent.

[Production Example 2-1: Production of microcapsule-type latent curing agent (H-1) having a core-shell structure]
300 g of n-hexane was used as the dispersion medium. 100 g of a finely pulverized epoxy resin curing agent (C-1) was added to the dispersion medium and dispersed, and then 1.0 g of water and 2.0 g of isophorone diisocyanate were added at 50 ° C. for 2 hours. It was reacted. After completion of the reaction, 100 g of bisphenol A type epoxy resin (Mitsubishi Chemical Co., Ltd. product "jER828") was added to the obtained reaction solution, and the mixture was filtered, washed and dried to obtain a microcapsule type curing agent for epoxy resin (H-). 1) was obtained.

[Production Example 2-2: Production of microcapsule-type latent curing agent (H-2) having a core-shell structure]
A microcapsule type latent curing agent for epoxy resin H-2 was obtained in the same order except that the epoxy resin curing agent C-1 of Production Example 2-1 was changed to C-2.

[Production Example 2-3: Production of microcapsule-type latent curing agent (H-3) having a core-shell structure]
To 200 g of bisphenol A type epoxy resin (Mitsubishi Chemical Co., Ltd. product "jER828"), 120 g of a finely pulverized microcapsule type latent curing agent core (C-3) obtained in Production Example 1-3 was added. After dispersion, 1.0 g of water and 5.5 g of hexane diisocyanate are added and reacted at 45 ° C. for 3 hours to have a core-shell structure, and the core is a core (C-3). A latent curing agent (H-3) was obtained.

[Production Example 2-4: Production of microcapsule-type latent curing agent (H-4) having a core-shell structure]
Epoxy was treated in the same procedure as in Production Example 2-3 except that the micropulverized product of the epoxy resin curing agent (C-3) in Production Example 2-3 was changed to the epoxy resin curing agent (C-4). A microcapsule type curing agent for resin (H-4) was obtained.

[Production Example 2-5: Production of microcapsule-type latent curing agent (H-5) having a core-shell structure]
Microcapsule type obtained in Production Example 1-5 in 200 g of bisphenol A type epoxy resin (Asahi Kasei E-Materials product "AER2603", epoxy equivalent 189 g / eq, total chlorine amount 1800 ppm, hydrolyzable chlorine amount 50 ppm) After adding 100 g of a micropulverized product of the core (C-5) of the latent curing agent and dispersing it, 1.0 g of water and 2.0 g of isophorone diisocyanate were added, and the reaction was carried out at 40 ° C. to 50 ° C. for 2 hours. A microcapsule type latent curing agent (H-5) having a core-shell structure and having a core (C-5) was obtained.

[Examples 1 to 22 and Comparative Examples 1 to 9]
A polypropylene (PP) container was attached to Shinky's product "Awatori Rentaro ARE-310". The epoxy resin, curing agent, and curing accelerator (curing catalyst) were blended in the blending amounts shown in Tables 2 to 5, and the mixture was stirred at 2000 rpm for 3 minutes for stirring and 2 minutes for defoaming. An epoxy resin composition was obtained by visually confirming that each formulation was mixed. The obtained epoxy resin composition was measured for the content of tertiary amino group nitrogen in the epoxy resin composition, low temperature curability, and stability during heating by the above-mentioned methods. The measurement results are shown in Tables 2-5.

(Epoxy resin (A))
BE-186EL: Bisphenol A type epoxy resin manufactured by Changchun Artificial Resin Co., Ltd., epoxy equivalent 181 g / eq

(Thiol hardener (B))
PEMP: SC Organic Chemical Co., Ltd., pentaerythritol tetrakis (3-mercaptopropionate), SH equivalent 122 g / eq
DPMP: SC Organic Chemical Co., Ltd., dipentaerythritol hexasis (3-mercaptopropionate), SH equivalent 131 g / eq
TMTP: Trimethylolpropanetris (3-mercaptopropionate) SH equivalent 140 g / eq manufactured by Yodo Kagaku Co., Ltd.

(Curing accelerator (curing catalyst))
H-1: Microcapsule type epoxy resin curing agent produced in Production Example 2-1 H-2: Microcapsule type epoxy resin curing agent produced in Production Example 2-2 H-3: Manufactured in Production Example 2-3 Microcapsule type epoxy resin curing agent H-4: Microcapsule type epoxy resin curing agent produced in Production Example 2-4 H-5: Microcapsule type epoxy resin curing agent produced in Production Example 2-5 BDMA: benzyldimethylamine (reagent)
DABCO: 1,4-diazabicyclo [2.2.2] Octane 2E4MZ: 2-Ethyl4-methylimidazole (reagent)

The epoxy resin composition of the present invention has industrial applicability in a wide range of applications such as insulating materials for electronic devices and electrical and electronic parts, sealing materials, adhesives, and conductive materials.

Claims (7)

An epoxy resin composition containing an epoxy resin (A), a thiol curing agent (B), and a curing accelerator (C).
An epoxy resin composition in which the curing accelerator (C) contains a reaction product of a compound represented by the formula (1) and an epoxy resin.
(In the formula (1), R ¹ and R ² are independently substituted alkyl groups having 1 or more and 8 or less carbon atoms, and optionally substituted cycloalkyl groups having 4 or more and 10 or less carbon atoms. A group or a optionally substituted benzyl group,
Each of X and Z is independently a hydrogen atom, an alkyl group having 1 or more and 8 or less carbon atoms which may be substituted, an aryl group which may be substituted, and 4 or more and 10 or less carbon atoms which may be substituted. Cycloalkyl group, or optionally substituted benzyl group,
n is an integer of 0 or more and 8 or less.
m is an integer of 0 or more and 4 or less. ) The curing accelerator (C) is a latent curing agent having a core-shell structure.
The epoxy resin composition according to claim 1. The curing accelerator (C) contains an amine compound (D) different from the compound represented by the formula (1).
The epoxy resin composition according to claim 1 or 2. The molecular weight of the amine compound (D) is
50 g / mol or more and 250 g / mol or less,
Containing at least one tertiary amino group,
The epoxy resin composition according to claim 3. The content of the amine compound (D) is 5 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the reaction product of the compound represented by the formula (1) and the epoxy resin.
The epoxy resin composition according to claim 3 or 4. The tertiary amine concentration is 0.01% by mass or more and 0.4% by mass or less.
The epoxy resin composition according to any one of claims 1 to 5. The thiol curing agent (B) contains a primary thiol.
The epoxy resin composition according to any one of claims 1 to 6.