JP2020152818A - Epoxy resin composition - Google Patents

Abstract

To provide an epoxy resin composition having excellent adhesiveness.SOLUTION: An epoxy resin composition has an epoxy resin and an epoxy resin curing agent, and has the ratio between a gelation time at 70°C (GT70) and a gelation time at 80°C (GT80), (GT70/GT80), of 2.5 or more.SELECTED DRAWING: 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.

An epoxy resin 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. Examples of the method of curing the composition include a method of using a liquid amine-based curing agent.

The two-component epoxy resin composition can be satisfactorily cured at a low temperature by using a liquid amine-based curing agent as described above. 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, a large amount of both cannot be mixed in advance because the pot life after that is limited. 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, such a 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.

On the other hand, 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 enable storage stability and 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).

Japanese Unexamined Patent Publication No. 2016-130287 Public Relations 2017/057019

Patent Document 1 describes an epoxy resin composition capable of obtaining a cured product having excellent light transmission and less cracking. Patent Document 2 describes an epoxy resin composition that can be cured at a low temperature for a short time and has excellent adhesive strength and pot life. However, the epoxy resin compositions disclosed in these documents are required to further improve the adhesiveness.

Therefore, an object of the present invention is to provide an epoxy resin composition having excellent adhesiveness.

As a result of intensive studies to solve the above problems, the present inventors have found that an epoxy resin composition having a gelation time ratio of 70 ° C. and 80 ° C. or more can solve the above problems. The present invention has been completed.

That is, the present invention is as follows.
[1]
Contains epoxy resin and epoxy resin curing agent
An epoxy resin composition in which the ratio (GT70 / GT80) of the gelation time at 70 ° C. (GT70) to the gelation time at 80 ° C. (GT80) is 2.5 or more.
[2]
The epoxy resin curing agent is a polythiol curing agent.
The epoxy resin composition according to [1], further comprising a curing accelerator.
[3]
The epoxy resin composition according to [1], wherein the gelation time at 70 ° C. (GT70) is 10 minutes or more, and the gelation time at 80 ° C. (GT80) is 5 minutes or less.
[4]
The epoxy resin composition according to [1], wherein the ratio (GT70 / GT80) of the gelation time at 70 ° C. (GT70) to the gelation time at 80 ° C. (GT80) is 10.0 or less.
[5]
The epoxy resin composition according to [2], wherein the curing accelerator is a latent curing agent having a core-shell structure.
[6]
The epoxy resin composition according to [5], which has a low molecular weight amine compound in the core of the curing accelerator.
[7]
The epoxy resin composition according to [5], which has a reaction product of an amine compound represented by the following structural formula (1) and an epoxy resin in the core of the curing accelerator.
(In the formula (1), R ₁ and R ₂ are independently substituted alkyl groups having 1 or more and 8 or less carbon atoms, optionally substituted cycloalkyl groups, or substituted. Benzyl groups may be indicated, and X and Z are independently hydrogen atoms, alkyl groups having 1 or more and 8 or less carbon atoms which may be substituted, aryl groups which may be substituted, and substituted. It indicates a cycloalkyl group which may be used, or a benzyl group which may be substituted, n indicates an integer of 0 or more and 8 or less, and m indicates an integer of 0 or more and 4 or less.)

According to the present invention, it is possible to provide an epoxy resin composition having excellent shear adhesiveness.

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 in various modifications within the scope of the gist thereof.

[Epoxy resin composition]
The epoxy resin composition of the present embodiment contains an epoxy resin and an epoxy resin curing agent. Further, in the epoxy resin composition of the present embodiment, the ratio (GT70 / GT80) of the gelation time at 70 ° C. (GT70) to the gelation time at 80 ° C. (GT80) is 2.5 or more.

The epoxy resin composition of the present embodiment is excellent in adhesiveness by having the above structure. This factor can be considered as follows, but the factor is not limited to this. That is, when the ratio (GT70 / GT80) of the gelation time at 70 ° C. (GT70) to the gelation time at 80 ° C. (GT80) is 2.5 or more, the curing at low temperature is slow and the curing at high temperature is high. It means that it cures quickly. Since curing at a low temperature is slow, the temperature of the formulation rises, the viscosity of the formulation decreases, and the curing agent component easily diffuses into the formulation, so that a uniform cured product can be easily obtained. Therefore, the stress can be uniformly relaxed, and the adhesive strength is increased. In addition, since the curing rate is high at high temperatures, it is considered that the curing progresses sufficiently at high temperatures and the cohesive force is exhibited, so that the adhesive force becomes high.

In the epoxy resin composition of the present embodiment, the lower limit of GT70 / GT80 is 2.5, preferably 3.0 or more, more preferably 3.5 or more, and 4.0 or more. It is more preferable to have. The upper limit of the GT70 / GT80 is not particularly limited, but is preferably 10.0 or less, more preferably 9.5 or less, and further preferably 9.0 or less. The epoxy resin composition of the present embodiment is excellent in adhesiveness because the GT70 / GT80 is in the above range. The method for controlling the GT70 / GT80 within the above range is not particularly limited, but for example, a method using a latent curing agent such as an amine salt or an imidazole derivative, or a method using a curing agent or a curing catalyst having a core-shell structure. , And a method of adjusting the amount of the curing agent and / or the curing catalyst used. As one embodiment, as a method of increasing the value of GT70, from the viewpoint of suppressing the reaction at a low temperature, a method of using a latent curing agent as a curing agent or a curing catalyst, and stabilization of suppressing the reaction of the curing agent or the curing catalyst. Examples thereof include a method of adding an agent, and examples of a method of reducing the value of GT80 include a method of using a curing agent or a curing catalyst having high reactivity at around 80 ° C. from the viewpoint of increasing reactivity.

In the epoxy resin composition of the present embodiment, the gelation time (GT70) at 70 ° C. is preferably 10 minutes or longer, more preferably 12 minutes or longer, and even more preferably 14 minutes or longer. The upper limit of the gelation time (GT70) at 70 ° C. is preferably 60 minutes or less, more preferably 50 minutes or less, and even more preferably 40 minutes or less. The epoxy resin composition of the present embodiment tends to be more excellent in adhesiveness when the gelation time at 70 ° C. is within the above range. Further, in the epoxy resin composition of the present embodiment, the gelation time (GT80) at 80 ° C. is preferably 5 minutes or less, more preferably 4 minutes or less, and further preferably 3 minutes or less. preferable. The lower limit of the gelation time (GT80) at 80 ° C. is preferably 0.3 minutes or more, more preferably 0.5 minutes or more, and more preferably 1 minute or more. The epoxy resin composition of the present embodiment tends to be more excellent in adhesiveness when the gelation time at 80 ° C. is within the above range.
In this embodiment, the gelation time of the epoxy resin composition can be measured by the method described in Examples described later.

(Epoxy resin)
The epoxy resin composition of the present embodiment contains an epoxy resin. The epoxy resin 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, diphenyl Sulfonate 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, catechol Bifunctional epoxy resins such as type epoxy resins and N, N-diglycidyl aniline type epoxy resins; N, N-diglycidyl aminobenzene type epoxy resins, o- (N, N-diglycidyl amino) toluene type epoxy resins , Trifunctional epoxy resins such as triazine type epoxy resin; tetrafunctional epoxy resins such as tetraglycidyldiaminodiphenylmethane type epoxy resin, diaminobenzene type epoxy resin; phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenyl Polyfunctional epoxy resins such as methane 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, these Examples thereof include epoxy resins obtained by modifying the epoxy resin of the above with isocyanate or the like. These epoxy resins may be used alone or in combination of two or more.

(Epoxy resin hardener)
The epoxy resin composition of the present embodiment contains an epoxy resin curing agent (hereinafter, also simply referred to as "curing agent"). The curing agent is not limited to the following as long as the effects of the present invention can be exhibited, but a polythiol curing agent (a thiol compound having two or more thiol groups in the molecule) is preferable from the viewpoint of low temperature curability. The polythiol curing agent is not particularly limited, and for example, trimethylolpropanthris (thioglycolate), pentaerythritol tetrakis (thioglycolate), ethylene glycol dithioglycolate, trimethylolpropanthris (β-thiopropionate), etc. Pentaerythritol tetrakis (β-thiopropionate), dipentaerythritol poly (β-thiopropionate) and other polyols and thiol compounds obtained by the esterification reaction of thiol organic acids, 1,4-butanedithiol, Alkyl polythiol compounds such as 1,6-hexanedithiol and 1,10-decandithiol, terminal thiol group-containing polyethers, terminal thiol group-containing polythioethers, thiol compounds obtained by the reaction of epoxy compounds with hydrogen sulfide, polythiols and epoxy compounds. Examples thereof include a thiol compound having a terminal thiol group obtained by the reaction with. Specifically, but not particularly limited, for example, pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexasis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate). And so on. These hardeners may be used alone or in combination of two or more.

(Curing accelerator)
The epoxy resin composition of the present embodiment preferably further contains a curing accelerator. The curing accelerator is not limited to the following as long as the effect of the present invention can be exhibited, but from the viewpoint of storage stability, a latent curing agent having a core-shell structure (hereinafter, "microcapsule type latent curing agent"). It is also described as.).

Here, it is preferable to have a low molecular weight amine compound in the core of the microcapsule type latent curing agent. As a result, the epoxy resin composition of the present embodiment has high curability and can exhibit sufficient cohesive force, so that the shear adhesive force is further improved.

The low molecular weight amine compound is not particularly limited, and examples thereof include a low molecular weight amine compound containing a tertiary amino group. The low molecular weight amine compound having a tertiary amino group is not limited to the following, and 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 low molecular weight amine compound contained in the core of the microcapsule type latent curing agent is preferably 2 to 15% by mass, more preferably 3 to 14% by mass, further preferably 4 to 10% by mass, and 4 to 7%. Mass% is even more preferred. When the proportion of the low molecular weight amine compound contained in the core of the microcapsule type latent curing agent is 2 to 15% by mass, it tends to be possible to achieve both curability and storage stability.

The core of the microcapsule type latent curing agent is not limited to the following, as long as the effect of the present invention can be exhibited, but the reaction between the epoxy resin and the amine compound represented by the following structural formula (1). It is a substance, and 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, optionally substituted cycloalkyl groups, or substituted. X and Z each independently represent a good benzyl group, an alkyl group having 1 or more and 8 or less carbon atoms which may be substituted, an aryl group which may be substituted, or an substituted aryl group. It represents a good cycloalkyl group or a optionally substituted benzyl group, where n represents an integer of 0 or more and 8 or less, and m represents an integer of 0 or more and 4 or less.

In R ₁ and R ₂ in the formula (1), the alkyl group having 1 or more and 8 or less carbon atoms which may be substituted is not particularly limited, but for example, a methyl group, an ethyl group, an n-propyl group, and the like. Isopropyl group, 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 and the like can be mentioned. The cycloalkyl group which may be substituted is not particularly limited, and examples thereof include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like.

The alkyl group having 1 or more and 8 or less carbon atoms which may be substituted and the cycloalkyl group which may be substituted, which are represented as X and Z in the formula (1), are not particularly limited. Examples thereof include alkyl groups having 1 or more and 8 or less carbon atoms which may be substituted, and cycloalkyl groups which may be substituted, which are represented as R ₁ and R ₂ , respectively. The aryl group that may be substituted is not particularly limited, and examples thereof include a phenyl group, a tolyl group, and an o-xylyl group.

In the epoxy resin composition of the present embodiment, from the viewpoint of curability and physical properties of the cured product, the amine compound represented by the above formula (1) is N, N-dimethylaminopropylamine, N, N-diethylaminopropyl. Amine, 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 at least one 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 an amine compound represented by the formula (1), and preferably has an amino group. The epoxy resin is not particularly limited, and examples thereof include those exemplified as the above-mentioned epoxy resin. 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.

Regarding the method for producing an amine adduct, the reaction conditions between the epoxy resin and the amine compound represented by the formula (1) are, if necessary, in the presence of a solvent at a temperature of 50 to 250 ° C. for 0.1 to 10 hours. It is preferable to react. 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); 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 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 effect that the storage stability of the epoxy resin composition is practically sufficient can be obtained. When the average particle size of the core of the microcapsule type latent curing agent is 12 μm or less, a more homogeneous cured product can be obtained. In addition, 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 , 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. Reliability is obtained.

The average particle size referred to here means an average particle size defined by the median diameter. More specifically, it 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.). Here, the method for controlling the average particle size of the core is not particularly limited, and some methods can be mentioned. Examples of such a method include a method of performing precise control in the crushing step of the core of the massive microcapsule type latent curing agent, and a coarse crushing step as a crushing step of the core of the massive microcapsule type latent curing agent. A method of performing a fine pulverization step and further classifying and obtaining a desired average particle size using a precision classifying device, a microcapsule type latent in which a core of a massive microcapsule type latent curing agent is dissolved in a solvent. Examples thereof include a method of spray-drying the core solution of the sex hardening agent. The apparatus used for pulverization is not particularly limited, and for example, a ball mill, an tryter, a bead mill, a jet mill and the like can be adopted as needed, but it is preferable to use an impact type pulverizer. Examples of the impact type crushing device include jet mills such as a swirling 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 a powder or granular material having a predetermined average particle size. And a method of classifying using a classifier, and a method of classifying by wind force according to the specific gravity of particles. The classifying machine to be used is not particularly limited, and examples thereof include a wet classifying machine and a dry classifying machine, but a dry classifying machine is generally preferable. Examples of such classifiers include "Elbow Jet" manufactured by Nittetsu Mining Co., Ltd., "Fine Sharp Separator" manufactured by Hosokawa Micron, "Variable Impactor" manufactured by Sankyo Electric Co., Ltd., and "Spedic Classifier" manufactured by Seishin Enterprise Co., Ltd. , Nippon Donaldson's "Donna Celec", Yasukawa Shoji's "YM Microcassette", Nisshin Engineering's "Turbo Classifier", and other various air separators, micron separators, microbrex, Accucut, etc. Examples include, but are not limited to, classifiers.

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. Specifically, the present invention is not particularly limited, and examples thereof 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. Another method is to obtain a core having a desired particle size range by filtering and separating the particles and then drying and removing the solvent at a low temperature below the melting point of the core. 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 pulverize 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 rotating 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 is not limited to the following, and may be, for example, spherical, granular, powdery, amorphous, or the like. 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 irregular 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 synthetic resin and / or an inorganic oxide. It is preferable to have. Among these, it is preferable to contain a synthetic resin from the viewpoints of the stability of the film constituting the shell, the ease of breaking during heating, and the uniformity of the cured product.

Examples of the synthetic resin include, but are not limited to, epoxy resins, phenol resins, polyester resins, polyethylene resins, nylon resins, polystyrene resins, urethane resins and the like. Among these, the synthetic resin is preferably an epoxy resin, a phenol resin, or a urethane resin.

The epoxy resin used for 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 resin produced by the above reaction, a compound having two or more epoxy groups, and a reaction product of 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, the reaction product of the amine-based curing agent and the epoxy resin is preferable from the viewpoint of film stability and low-temperature quick-curing property.

The phenolic resin is not limited to the following, but for example, phenol / formaldehyde polycondensate, cresol / formaldehyde polycondensate, resorcinol / formaldehyde polycondensate, bisphenol A / formaldehyde polycondensate, phenol / formaldehyde. Examples thereof include a modified polyethylene polyamine of a polycondensate.

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

Examples of the polyethylene-based resin include, but are not limited to, ethylene / propylene / vinyl alcohol copolymers, ethylene / vinyl acetate copolymers, ethylene / vinyl acetate / acrylic acid copolymers, and the like. ..

Nylon-based resins include, but are not limited to, adipic acid / hexamethylenediamine polycondensate, sebacic acid / hexamethylenediamine polycondensate, p-phenylenediamine / terephthalic acid polycondensate, and the like. ..

The polystyrene-based resin is not limited to the following, but is, for example, a styrene-butadiene copolymer, a styrene-butadiene-acrylonitrile copolymer, an acrylonitrile-styrene-divinylbenzene copolymer, and a styrene-propenyl alcohol copolymer. Things etc. can be mentioned.

The urethane-based resin is not limited to the following, but for example, butyl isocyanate, cyclohexyl isocyanate, octadecyl isocyanate, phenyl isocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, trizine diisocyanate. , Naphthalene diisocyanate, triphenylmethane triisocyanate and other isocyanate monomers, or condensates thereof, polymers thereof, and polycondensates of monoalcohols and polyhydric alcohols. Among these, monoalcohol or polyhydric alcohol and urethane resin which is an addition product of monoisocyanate or polyhydric isocyanate are preferable.

Examples of the inorganic oxide include, but are not limited to, boron oxide, boron compounds such as boric acid ester, silicon dioxide, calcium oxide and the like. Among these, boron oxide is preferable from the viewpoint of film stability and easiness of breaking during heating.

Further, the shell constituting the microcapsule type latent curing agent preferably contains any two or more reaction products of an isocyanate compound, an active hydrogen compound, an epoxy resin curing agent, an epoxy resin, and an amine compound. ..

The isocyanate compound may be one contained in the core of the microcapsule type latent curing agent.
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. Be done. In addition, 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.

The alicyclic amine is not limited to the following, and examples thereof include cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine, and isophoronediamine.

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 any of primary alcohols, secondary alcohols and 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.

The reaction conditions for producing any two or more of the above-mentioned isocyanate compounds, active hydrogen compounds, epoxy resin curing agents, epoxy resins, and amine compounds are not particularly limited, but are usually used. The reaction time is 10 minutes to 12 hours in the temperature range of -10 ° C to 150 ° C.

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: Phosphate 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. to 150 ° C., preferably 0 ° C. to 100 ° C. for 1 hour to 168 hours, preferably 2 hours to 72 hours. It takes place in reaction time. The dispersion medium is preferably a solvent or a plasticizer.
The proportion of the reaction product as described above in the shell (S) is usually 1% by mass or more, preferably 50% by mass or more, and may be 100% by mass.

The method for forming the shell that covers the surface of the core in the microcapsule type latent curing agent is not particularly limited, and examples thereof include the following methods (1) to (3).
(1) After dissolving and dispersing the shell components and the core particles of the microcapsule type latent curing agent having an average particle size of more than 0.3 μm and 12 μm or less in the solvent which is the dispersion medium, the dispersion medium A method of lowering the solubility of the components of the shell inside to deposit the shell on the surface of the particles of the core of the microcapsule type latent curing agent.
(2) Particles of the core of the microcapsule type latent curing agent having an average particle size of more than 0.3 μm and 12 μm or less are dispersed in a dispersion medium, and the material for forming the above shell is added to the dispersion medium to make an epoxy. A method of depositing on particles of a resin curing agent.
(3) The above-mentioned raw material components forming the shell are added to the dispersion medium, and the surface of the core particles of the microcapsule type latent curing agent having an average particle size of more than 0.3 μm and 12 μm or less is used as a reaction field. Therefore, a method of producing a shell-forming material.
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) 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 the 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 dispersion medium or a solvent that does not dissolve 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, it is preferable to use an epoxy resin as the dispersion medium because a liquid resin composition composed of the epoxy resin and the microcapsule type latent curing agent can be obtained at the same time as the shell is formed.

The shell formation reaction is usually carried out in a temperature range of −10 ° C. to 150 ° C., preferably 0 ° C. to 100 ° C., for a reaction time of 10 minutes to 72 hours, preferably 30 minutes to 24 hours.

Further, the shell, in view of the balance between the 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, It is preferable to have a urethane bonding group that absorbs infrared rays having a wave number of 1730 to 1755 cm- ¹ . The urea bond group, the bullet bond group, and the urethane bond 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 burette-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 group, burette-binding group, and urethane-binding group can be observed.

The thickness of the shell is preferably 5 nm to 1000 nm, more preferably 10 nm to 100 nm. By setting the thickness of the shell to 5 nm or more, the storage stability of the epoxy resin composition of the present embodiment can be further improved. Further, by setting the thickness of the shell to 1000 nm or less, the curability can be further 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) can 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-trilborate , Tri-m-tolylborate, triethanolamine borate and the like. Further, as the borate compound, a cyclic borate ester having a cyclic structure in the molecule can also be used. The cyclic borate ester is not particularly limited, and is, for example, tris-o-phenylene bisborate, bis-o-phenylene pyroborate, bis-2,3-dimethylethylenephenylene pyroborate, bis-2,2-dimethyltri. Methylenepyroborate and the like can be mentioned.
The product containing such boric acid ester is not particularly limited, but for example, "Cure Duct" (registered trademark) L-01B (Shikoku Kasei Kogyo Co., Ltd.), "Cure Duct" (registered trademark) L-07N (Shikoku). Kasei Kogyo Co., Ltd. can be mentioned.

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, phenylisocyanate, p-chlorophenylisocyanate, benzylisocyanate, hexamethylenediisocyanate, 2-ethylphenylisocyanate, 2,6-. Dimethylphenyl isocyanate, tolylene diisocyanate (eg 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate), 1,5-naphthalenedi isocyanate, diphenylmethane-4,4'-diisocyanate, trizine diisocyanate, isophorone diisocyanate, xylyl Examples thereof include range isocyanate, paraphenylene diisocyanate, and bicycloheptane triisocyanate.

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 acid such as acrylic acid, methacrylic acid and crotonic acid. Halogenized fatty acids such as monobasic 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. , An aliphatic polybasic acid such as maleic acid, an aromatic monobasic acid such as benzoic acid halogenated benzoic acid, toluic acid, phenylacetic acid, cinnamic acid, and mandelic acid, and an aromatic polybasic acid such as phthalic acid and trimesic acid. And so on.

The acid anhydride is not particularly limited, and is, for example, a fat such as succinic anhydride, dodecynyl succinic anhydride, maleic anhydride, an adduct of methylcyclopentadiene and maleic anhydride, hexahydrophthalic anhydride, and methyltetrahydrophthalic anhydride. Group polybasic acid anhydrides; aromatic polybasic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyrrolimellitic anhydride; can be mentioned.

The content of the epoxy resin and the epoxy resin curing agent is not particularly limited, and the active hydroxyl equivalent of the epoxy resin curing agent is preferably 0.5 to 3.0 equivalents, preferably 0.7 to 3.0 equivalents, with respect to the epoxy equivalent of the epoxy resin. It is more preferably 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 curing accelerator is preferably 0.1 to 80 parts by mass, more preferably 1 to 70 parts by mass with respect to 100 parts by mass of the epoxy resin. It is preferably 1 to 60 parts by mass, and more preferably 1 to 60 parts by mass.

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.

(Measurement of gelation time)
The gelation time of the epoxy resin compositions of Examples and Comparative Examples was measured by a method based on JIS K6910. Weigh 0.5 ± 0.05 g of the sample on a hot plate with a dent that has been warmed to a predetermined temperature in advance, inject it into the dent with a syringe, press the stopwatch, and stir the sample using a pointed stick. The point at which the thread did not pull when the rod was lifted was defined as the gelling time at that temperature. The gelation time at 70 ° C. (GT70) and the gelation time at 80 ° C. (GT80) were measured, and the ratio (GT70 / GT80) was calculated.

(Shear adhesive strength)
Using the epoxy resin compositions of Examples and Comparative Examples, test pieces were prepared in accordance with JIS K6850. Further, as the adherend, an adherend (cold-rolled steel plate) having a width of 25 mm, a length of 100 mm, and a thickness of 1.6 mm conforming to JIS C3141 was used. An uncured test piece was placed in a small high-temperature chamber ST-110B2 manufactured by ESPEC Co., Ltd., whose internal temperature was stable at 80 ° C., and heated for 60 minutes to obtain a shear bond strength measurement test piece. After 60 minutes, the structure was removed from the small high temperature chamber and left in a room temperature environment to cool to room temperature. After cooling to room temperature, using AGX-5kNX manufactured by Shimadzu Corporation, the adhesive surface of the test piece broke at a load cell of 5 kN and a speed of 5 mm / min, and the maximum load at which the test piece separated was measured and separated. The value obtained by dividing the maximum load by the bonding area was defined as the shear bonding strength. From the obtained shear adhesive strength, the shear adhesiveness was evaluated based on the following criteria.
⊚: When the shear adhesive strength is 20 MPa or more.
◯: When the shear adhesive strength is 18 MPa or more and less than 20 MPa.
X: When the shear adhesive strength is less than 18 MPa.

[Manufacturing Example 1-1]
(Manufacture of core (C-1) of microcapsule type latent curing agent)
To 605 g of a solution prepared by mixing 1-butanol and toluene at a ratio of 1/1 (mass ratio), 403 g of N, N-dimethylaminopropylamine (molecular weight 102) was added as an amine compound, and the mixture was stirred to prepare a uniform solution. did.
Next, 800 g of a bisphenol A type epoxy resin (Mitsubishi Chemical Corporation product "jER828") having an epoxy equivalent of 189 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). 800 g of a bisphenol A type epoxy resin (Mitsubishi Chemical Co., Ltd. product "jER1001") having an epoxy equivalent of 475 g / eq was dissolved to obtain a bisphenol A type epoxy resin solution.
In a reaction vessel equipped with a stirrer, a condenser, and an OIL bath for temperature control, the internal temperature of the bisphenol A type epoxy resin solution is 50 to 90 to the N, N-dimethylaminopropylamine solution using an isobaric dropping funnel. It was added dropwise over 5 hours in the range of ° C.
After completion of the dropping, the obtained reaction solution was heated at 80 ° C. for 2 hours.
Then, the temperature of the reaction solution was further raised to 150 ° C., and then the pressure was gradually reduced to distill off a part of the solvent from the reaction solution. At this stage, the content of N, N-dimethylaminopropylamine was 0.1% by mass.
After distilling off the solvent, the reaction solution is further heated at 165 ° C., and 220 g of DABCO (1,4-diazabicyclo [2.2.2] octane manufactured by Tokyo Kasei Co., Ltd.) is stirred and mixed at 60 rpm at 165 ° C. for 1 hour. The mixture was discharged from the flask to obtain a block-shaped amine adduct mixture.
The amine adduct mixture prepared by the above procedure was coarsely crushed by a crusher "Rohtoplex" (manufactured by Hosokawa Micron Co., Ltd.) until the average particle size became about 0.1 to 2 mm to obtain a coarse powder. The obtained pyroclastic material was supplied to an air-flow jet mill (“CJ25 type” manufactured by Nisshin Engineering Co., Ltd.) at a supply amount of 8.0 kg / hour, and crushed twice at a crushing pressure of 0.6 MPa · s. Repeatedly, after that, classification is performed by an air classifier (manufactured by Nisshin Engineering Co., Ltd., "Turboclassifier") to remove coarse particles, and the core of a microcapsule type latent curing agent having an average particle size of 5.0 μm ( C-1) was obtained.

[Manufacturing Example 1-2]
(Manufacture of core (C-2) of microcapsule type latent curing agent)
N, N-dimethylaminopropylamine of Production Example 1-1 was added to 513 g of N, N-diethylaminopropylamine (molecular weight 130), and DABCO was added to DBU (manufactured by Tokyo Kasei Co., Ltd., 1,8-diazabicyclo [5.4.0]. It was prepared in the same procedure as the microcapsule type latent curing agent core (C-1) except that it was changed to -7-undecene), and the microcapsule type latent curing agent core (C-) having an average particle size of 4.5 μm was prepared. 2) was obtained.

[Manufacturing Example 1-3]
Except for changing N, N-dimethylaminopropylamine of Production Example 1-1 to 347 g of N, N-dimethylaminoethylamine (molecular weight 88) and DABCO to BDMA (manufactured by Tokyo Kasei Co., Ltd., N, N-dimethylbenzylamine). Was prepared in the same procedure as the microcapsule type latent curing agent core (C-1) to obtain a microcapsule type latent curing agent core (C-3) having an average particle size of 4.0 μm.

[Manufacturing Example 1-4]
(Manufacture of microcapsule type latent curing agent core (C-4))
After dissolving 110 g of 2-ethyl-4-methylimidazole (molecular weight 110) 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 E-Material) as an epoxy resin at 60 to 100 ° C. 189 g of "AER2603" manufactured by Zu Co., Ltd., epoxy equivalent 189, total chlorine amount 1800 ppm, hydrolyzable chlorine 50 ppm) was added and reacted.
Then, by heating and reducing the pressure of the reaction solution, xylene and isopropyl alcohol as solvents are distilled off from the reaction solution, and the unreacted diethylenetriamine is distilled off until the content is less than 0.01% by mass. , 263 g of amine adduct was obtained.
The amine adduct produced by the above procedure was pulverized in the same procedure as the microcapsule type latent curing agent core (C-1) to obtain a microcapsule type latent curing agent core (C-4).

[Manufacturing Example 2-1]
(Manufacture of microcapsule type latent curing agent (H-1) having a core-shell structure)
Finely pulverized the core (C-1) of the microcapsule type latent curing agent obtained in Production Example 1-1 in 100 g of a bisphenol A type epoxy resin (Mitsubishi Chemical Corporation product "jER828", epoxy equivalent 189 g / eq). After 120 g of the product was added and dispersed, 1.0 g of water and 5.5 g of tolylene diisocyanate were added and reacted at 40 ° C. to 50 ° C. for 2 hours to have a core-shell structure, and the core had a core. A microcapsule type latent curing agent (H-1) which is (C-1) was obtained.

[Manufacturing Example 2-2]
(Manufacture of microcapsule type latent curing agent (H-2) having a core-shell structure)
300 g of n-hexane was used as the dispersion medium. To the dispersion medium, 100 g of a finely pulverized product of the epoxy resin curing agent (C-2) is added and dispersed, and then 1.0 g of water and 4.5 g of hexamethylene diisocyanate are added and the temperature is 40 ° C. for 2 hours. , Reacted. After completion of the reaction, 100 g of bisphenol A type epoxy resin (Mitsubishi Chemical Corporation 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-). 2) was obtained.

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

[Manufacturing Example 2-4]
(Manufacture of hardener (H-4) having a core-shell structure)
Microcapsule type obtained in Production Example 1-2 in 200 g of bisphenol A type epoxy resin (Asahi Kasei Ematerials 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-4) 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-4) having a core-shell structure and having a core (C-4) was obtained.

[Examples 1 to 13 and Comparative Examples 1 to 10]
A 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 gelation time and adhesiveness of the obtained epoxy resin composition were measured by the above methods. The measurement results are shown in Tables 2-5.

(Epoxy resin)
BE-186EL: Bisphenol A type epoxy resin manufactured by Changchun Artificial Resin Co., Ltd., epoxy equivalent 189 g / eq

(Hardener)
PEMP: SC Organic Chemistry, Pentaerythritol Tetrakis (3-mercaptopropionate), SH equivalent 122 g / eq
DPMP: SC Organic Chemistry, dipentaerythritol hexasis (3-mercaptopropionate), SH equivalent 131 g / eq
TMTP: Trimethylolpropanetris (3-mercaptopropionate) SH equivalent 140 g / eq manufactured by Yodo Chemical 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 2MZ: 2-Methylimidazole (reagent)
BDMA: benzyldimethylamine (reagent)
2E4MZ: 2-Ethyl4-methylimidazole (reagent)

(Stabilizer)
L-07N: Boric acid ester compound (Shikoku Chemicals Corporation)
TBB: Tributyl Borate (Reagent)
TEB: Triethyl borate (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)

Contains epoxy resin and epoxy resin curing agent
An epoxy resin composition in which the ratio (GT70 / GT80) of the gelation time at 70 ° C. (GT70) to the gelation time at 80 ° C. (GT80) is 2.5 or more. The epoxy resin curing agent is a polythiol curing agent.
The epoxy resin composition according to claim 1, further comprising a curing accelerator. The epoxy resin composition according to claim 1, wherein the gelation time (GT70) at 70 ° C. is 10 minutes or more, and the gelation time (GT80) at 80 ° C. is 5 minutes or less. The epoxy resin composition according to claim 1, wherein the ratio (GT70 / GT80) of the gelation time at 70 ° C. (GT70) to the gelation time at 80 ° C. (GT80) is 10.0 or less. The epoxy resin composition according to claim 2, wherein the curing accelerator is a latent curing agent having a core-shell structure. The epoxy resin composition according to claim 5, which has a low molecular weight amine compound in the core of the curing accelerator. The epoxy resin composition according to claim 5, which comprises a reaction product of an amine compound represented by the following structural formula (1) and an epoxy resin in the core of the curing accelerator.
(In the formula (1), R ₁ and R ₂ are independently substituted alkyl groups having 1 or more and 8 or less carbon atoms, optionally substituted cycloalkyl groups, or substituted. Benzyl groups may be indicated, and X and Z are independently hydrogen atoms, alkyl groups having 1 or more and 8 or less carbon atoms which may be substituted, aryl groups which may be substituted, and substituted. It indicates a cycloalkyl group which may be used, or a benzyl group which may be substituted, n indicates an integer of 0 or more and 8 or less, and m indicates an integer of 0 or more and 4 or less.)