JP3270775B2 - Improved latent curing agent for epoxy resin and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to an improved latent hardener fine powder for epoxy resin and a method for producing the same. More specifically, the present invention relates to a latent curing agent for an epoxy resin or a latent curing agent for a high-temperature curing type, which has a low-temperature fast-curing property and is excellent in storage stability at room temperature, solvent resistance and cured physical properties. The present invention relates to a curing accelerator particle and a method for producing the same.

(Prior art) Epoxy resin cured products are excellent in adhesiveness, mechanical properties, thermal properties and electrical properties, so that they are widely used as paints, adhesives, and electrical / electronic insulating materials. It is used for Epoxy resin formulations used for these applications are broadly divided into one-component and two-component systems.

[0003] The most commonly used epoxy resin formulations are of the two-component type. The two-component compound is composed of an epoxy resin compound and a curing agent or a compound thereof, and these are stored separately, and both are measured and mixed as necessary for use. Such disadvantages are pointed out. (1) It is difficult to always obtain a homogeneous cured composition by avoiding measurement errors. (2) Variations in performance due to imperfect mixing and defoaming are likely to occur. (3)
The reaction between the epoxy resin and the curing agent starts at the same time as mixing,
The viscosity of the system gradually increases until it hardens through gelation. The viscosity of the formulation changes over time, making its application to automation impossible. (4) The pot life of the compound is determined by the chemical structure and composition of the epoxy resin and the curing agent. Generally, the faster the curing speed, the shorter the pot life. If the cure rate is the main focus, room-temperature or low-temperature curing compounding is possible, but the working time is inevitably shortened, and it is unavoidable that the working efficiency is greatly reduced, such as the necessity of frequently compounding a small amount.

On the other hand, in the case of the one-component system, since the curing agent is previously added to the epoxy resin, all problems associated with the two-component system are eliminated. However, in order to prepare a one-component epoxy resin composition having good storage stability at room temperature, a latent curing agent is required as a curing agent. Several latent curing agents have been proposed for this purpose. The simplest latent curing agents are solid at room temperature and do not dissolve in the epoxy resin, but disperse latent curing agents that dissolve when heated to near the melting point and start the reaction rapidly, such as dicyandiamide, phenol novolak, and adipin Acid dihydrazide, diallyl melamine, diamino maleonitrile, boron trifluoride-amine complex,
Examples include amine salts and imidazole derivatives. Although they are excellent in storage stability at room temperature, most of them are high-temperature curing types, and have a drawback that they require high-temperature curing at 160 ° C. or higher for a long time. Similarly, an acid anhydride curing agent, for example, methylhexahydrophthalic anhydride liquid at room temperature is also a kind of high-temperature curing type curing agent, reflecting its curing reaction mechanism, having a low hydroxyl group concentration. The compound with the liquid epoxy resin is relatively stable at room temperature, but has a disadvantage that the reaction rate is extremely slow, and the reaction hardly proceeds even when heated to about 160 ° C.

When using these high-temperature curing type curing agents,
Usually, tertiary amines represented by tris (dimethylaminomethyl) phenol,
It is known to use a curing accelerator such as an imidazole compound represented by ethyl-4-methylimidazole in combination. However, when a curing accelerator is added, the curing temperature becomes 12
Although it is possible to lower the temperature to 0 to 150 ° C., on the other hand, the storage stability is significantly impaired, and the potential advantage of the high-temperature curing type curing agent cannot be exhibited.

Other latent curing agents include, for example, amine imide compounds activated by thermal decomposition, ketimine compounds activated by contact with moisture, aromatic diazonium salt compounds activated by light irradiation, diallyliodonium Salt compounds, triallylsulfonium salts or selenium salt compounds, hardeners microencapsulated with materials that are destroyed by mechanical pressure or heat, and the like. Among them, the most advanced is a curing agent in which solid particles of an amine compound / epoxy compound adduct are treated with a polyfunctional isocyanate compound in the presence of a liquid epoxy resin to greatly improve the potential thereof. These techniques are disclosed in Japanese Unexamined Patent Publication No. 64-70523 and Japanese Unexamined Patent Publication No. Hei 1-113480. In this case, it is presumed that an encapsulation film is formed on the surface of the hardener particles.

The amine compound / epoxy compound adduct is
It is obtained by reacting an amine compound and an epoxy compound.The disadvantages of amine compound curing agents, such as volatility, which is a problem in handling, as well as hygroscopicity that greatly affects curability and compatibility with epoxy resins, etc. Not only is it significantly improved, but also control of the melting point is possible. In terms of performance,
Anionic polymerization catalyzed curing agents, such as tertiary amine adducts, which are not susceptible to metal corrosion, are preferred. Particularly suitable for this purpose in practical use is an imidazole compound / epoxy resin adduct, as disclosed in JP-A-58-13623 and JP-A-61-1986.
No. 268721.

[0008] According to these conventional methods, the amine compound / epoxy compound adduct is first obtained as a mass by reacting the amine compound with the epoxy resin in an organic solvent and then removing the solvent from the system. Next, this is pulverized and classified to take out hardener particles of a desired size. In this case, the size of the adduct curing agent particles is important, and the smaller the size, the higher the curing speed but the lower the storage stability. Conversely, as the particle size increases, the storage stability is improved, but the low-temperature curability tends to be impaired, and it is difficult to obtain a curing agent that is sufficiently satisfactory in both curability and storage stability.

It is also known that when an amine compound and an epoxy compound are reacted with each other, an excess amount of a polyfunctional epoxy compound as an epoxy compound relative to the amine compound improves the storage stability of the resulting adduct. ing. This is thought to be because the excess polyfunctional epoxy compound causes a polymerization reaction, the polymerized epoxy resin is mixed in the adduct particles, and the concentration of the reactive group on the adduct particle surface is diluted. ing. However, according to such a method, the storage stability is improved and, at the same time, the melting point of the adduct increases, so that the low-temperature curability is lost. Although storage stability is improved, direct contact between the reactive group and the compounded resin is unavoidable, so that it has not reached a practical level.

[0010] Further, in order to impart a potential to the pulverized and classified adduct particles having a small average particle diameter, which is considered to have a high curing speed, conventionally, the adduct particles are dispersed in a liquid epoxy resin and heated to a multifunctional state. By adding and reacting a reactive isocyanate compound, a master batch of a desired curing agent is produced. However, in this state, a side reaction such as polymerization of the dispersion medium epoxy resin inevitably occurs, so that the obtained curing agent master batch often has a very high viscosity, is difficult to handle, and has an epoxy resin cured composition. It is not preferable because it lowers the degree of freedom in the formulation design.

Recently, some application fields related to epoxy resins, such as solder resist inks for electronic materials,
In fields such as conductive paints / adhesives, prepregs for lamination, and metal anticorrosion primers, organic solvents and reactive diluents are often incorporated into cured compositions in order to reduce the viscosity of the cured compositions. Has become. In this case, in order to prepare a one-component epoxy resin cured composition having excellent storage stability, the solvent resistance of the latent curing agent to be added becomes important. Further, in the application field of electronic materials, a one-component epoxy resin cured composition excellent in low-temperature fast-curing and excellent in storage stability is strongly desired for reasons such as energy saving, improvement of line productivity and protection of electronic parts. Although it is rare, at present there is little known that meets all the above requirements.

(Problems to be Solved by the Invention) As described above, the amine compound / epoxy compound adduct particles are
In spite of having excellent advantages as a curing agent for epoxy resins, the one-component epoxy resin cured composition has not been fully utilized due to the above-mentioned various problems.

In order to take advantage of the one-component epoxy resin cured composition, the production process is simplified, the production cost is low, the particle size can be easily controlled, the solvent resistance is high, and There is a great demand for a latent hardener fine powder having excellent low-temperature fast-curing properties, storage stability, and physical properties of the resulting cured product.

(Means for Solving the Problems) From the above viewpoint, the present inventors have overcome the problems of the prior art amine compound / epoxy compound adduct particles and have achieved a one-component epoxy resin cured composition. As a result of intensive research to develop a curing agent that can make full use of the advantages of the product, the carboxylic acid compound acts on the amine compound / epoxy compound adduct particles to allow the adduct particles to react rapidly and at low temperatures as a curing agent. And a latent curing agent for the epoxy resin of the adduct particles by excessively using the polyfunctional epoxy compound or by reacting the adduct particles with the polyfunctional isocyanate compound. In combination with techniques to improve the potential as a low-temperature fast curing, storage stability, solvent resistance, etc. all greatly It found that Dekiru good, has been led to completion of the present invention.

That is, in one aspect, the present invention provides:
In reacting the amine compound and the epoxy compound to form adduct particles, an excess amount of the polyfunctional epoxy compound is used as the epoxy compound with respect to the amine compound. Compound containing a polymer portion therein /
Producing an epoxy compound adduct, grinding the adduct to form amine compound / epoxy compound adduct particles,
Thereafter, a polyfunctional isocyanate compound is further reacted with the adduct particles, before or after formation of the amine compound / epoxy compound adduct and before pulverization of the adduct or pulverization of the adduct At any time after and before the reaction with the polyfunctional isocyanate compound,
The present invention relates to a method for producing latent curing agent particles for an epoxy resin, which comprises reacting a carboxylic acid compound.

In another aspect, the present invention provides an adduct formed by reacting an amine compound with an epoxy compound to form an adduct, pulverizing the adduct to form adduct particles, and further adding a polyfunctional compound. A method of further reacting a reactive epoxy compound followed by a further reaction with a polyfunctional isocyanate compound, before or after formation of the amine compound / epoxy compound adduct and before pulverization of the adduct or the adduct A method for producing latent curing agent particles for an epoxy resin, characterized in that a carboxylic acid compound is reacted at an arbitrary point after the pulverization of a polyfunctional isocyanate compound with the polyfunctional isocyanate compound.

Further, the idea of the present invention is obtained by applying the amine compound and the epoxy compound as an organic solvent during the addition reaction of the amine compound and the epoxy compound in an organic solvent in the prior art, which was previously filed by the present applicant. The adduct obtained is selected from those that do not dissolve, and a suitable dispersion stabilizer coexists to stably disperse the resulting adduct particles without agglomeration, thereby being extremely useful as a curing agent for a latent epoxy resin. The method can also be improved by applying to a method of obtaining spherical amine compound / epoxy compound adduct particles having a controlled particle diameter in one step (Japanese Patent Application No. 2-138176 of the present applicant). In this case,
Disadvantages due to the above-mentioned pulverization method, that is, pulverization is limited, it is extremely difficult to produce fine particles having a Stokes diameter of 3 μm or less industrially, removal of solvent, fine pulverization / classification, etc. It takes a lot of energy and the production process is very expensive due to the long and complicated production process.
It is bulky and inconvenient for packaging and transportation due to the pulverized form, disadvantages such as a large contribution to the viscosity of the epoxy resin cured composition are further eliminated, and compared with the case where the carboxylic acid compound is not reacted. Thus, storage stability, low-temperature quick-curability, cured physical properties, and solvent resistance can all be greatly improved, and therefore, latent curing agent particles for epoxy resins having even higher industrial value are provided.

In other words, in another embodiment, the present invention dissolves both an amine compound and an epoxy compound in the presence of a dispersion stabilizer, and dissolves the amine compound and the epoxy compound together. In producing an adduct particle having a spherical shape by reacting in an organic solvent that does not dissolve, an additional polyfunctional epoxy compound may be further present during the reaction between the amine compound and the epoxy compound, or After completion, an additional polyfunctional epoxy compound is added and further reacted to form an amine compound / epoxy compound adduct spherical particle having an encapsulating layer formed on the surface by the polyfunctional epoxy compound. By reacting the obtained adduct spherical particles with a polyfunctional isocyanate compound, the amine compound and the epoxy compound The shape synthesized from the surface of the spherical adduct further has an encapsulation layer formed of an epoxy resin, further encapsulation layer formed by a polyfunctional isocyanate compound on the epoxy encapsulation layer, or A method for producing a spherical adduct particle having a mixed encapsulating layer of the above two, wherein the spherical adduct particle is formed by a polyfunctional epoxy compound before or after the formation of the amine compound / epoxy compound spherical adduct particle or on the surface thereof. Amine compound having encapsulating layer /
The present invention relates to a method characterized by reacting a carboxylic acid compound with the adduct particles at any time after the formation of the epoxy compound spherical adduct particles and before the reaction of the polyfunctional isocyanate compound.

According to this aspect of the present invention, in addition to the above-mentioned advantages, operations such as fine pulverization, classification and kneading of high viscosity can be performed as compared with the conventional method of preparing a latent curing agent by a pulverization / master batch method. Is unnecessary, the manufacturing process is considerably simplified, and the manufacturing cost can be greatly reduced. In addition, spherical adduct particles have advantages such as a higher bulk density than pulverized particles and a small contribution to the viscosity of the epoxy resin compound. Further, according to the present invention, the latency of the amine compound / epoxy compound adduct spherical particles as a latent curing agent for an epoxy resin, the low-temperature rapid curing property, and the solvent resistance are all determined by the reaction between the amine compound and the epoxy compound. By using only the above-mentioned treatment in the process of the above, the curing performance and the cured physical properties of the epoxy resin composition are greatly improved without impairing.

Hereinafter, the present invention will be described in more detail.

First, an amine compound and an epoxy compound which are raw materials of an adduct constituting the latent curing agent of the present invention are selected in consideration of the properties of the adduct as a curing agent. Important are the chemical structure that promotes anionic polymerization curing, the melting point, the excellent compatibility with the compounded epoxy resin to be cured in the molten state, the rapid curing properties, and the effect of addition (high curing reactivity with a small amount of addition).

Although all types of amine compounds can be used for this purpose, they are restricted by the type of epoxy compound to be combined therewith. because,
This is because, in order to synthesize a pure adduct, it is necessary to avoid polymerization and stop the addition reaction.

Although it is possible to combine all types of amine compounds with the monofunctional epoxy compound, the combination with the polyfunctional epoxy compound is as follows.
Only amine compounds having only one active hydrogen contributing to the reaction with the epoxy group are obtained. In any case, it is desirable to include a tertiary amino group having no active hydrogen. This is preferable because it increases the concentration of amino groups that contribute to the curing reaction of the adduct, that is, enhances the effect of addition as a curing agent. Furthermore, if the conditions for this combination are satisfied, one or more amine compounds may be used in combination.

Specific examples of the amine compound which can be combined with the polyfunctional epoxy compound include imidazole compounds represented by 2-methylimidazole and 2,4-dimethylimidazole, imidazoline compounds represented by imidazoline and 2-methylimidazoline, and the like. Piperazine compounds represented by N-methylpiperazine and N-hydroxyethylpiperazine, anabasin compounds represented by anabasin,
Examples include pyrazole compounds represented by 3,5-dimethylpyrazole, purine compounds represented by tetramethylguanidine and purine, and triazole compounds represented by 1,2,4-triazole.

All kinds of epoxy compounds as the other raw material can be used. For example, monofunctional epoxy compounds include n-butyl glycidyl ether, styrene oxide, phenylglycidyl ether, and bifunctional epoxy compounds include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl. ether,
Phthalic acid diglycidyl ester, trifunctional epoxy compound as triglycidyl isocyanurate, triglycidyl paraaminophenol, tetrafunctional epoxy compound as tetraglycidyl metaxylenediamine,
Tetraglycidyl diaminodiphenylmethane and epoxy compounds having a higher functional group include cresol novolak polyglycidyl ether and phenol novolak polyglycidyl ether. However, it is the same as described for the amine compound that it is restricted by the type of the amine compound to be combined. That is,
An amine compound having only one active hydrogen can be combined with all kinds of epoxy compounds, but an amine compound having two or more active hydrogens can be combined only with a monofunctional epoxy compound. is there.

The epoxy compound is selected in consideration of the melting point of the adduct to be produced and the compatibility with the epoxy resin to be cured in the molten state. Bisphenol A diglycidyl ether occupies an overwhelming amount as the epoxy resin to be cured. Therefore, as an epoxy compound as a raw material of the adduct, this epoxy compound has excellent compatibility with the epoxy compound and is advantageous in cost. Compounds are commonly used.
In an epoxy compound, the epoxy concentration is represented by the reciprocal of the epoxy equivalent (grams per equivalent). The lower the epoxy equivalent, the higher the epoxy group concentration. A high epoxy group concentration is desirable in order to increase the concentration of the tertiary amino group contained in the adduct formed by the addition reaction with the amine as much as possible to enhance the effect of addition as a curing agent. Therefore, it is desired that the epoxy equivalent of the epoxy compound be as small as possible. Usually, 1000 or less, preferably 500 or less epoxy compounds are used.

The melting point of the amine compound / epoxy compound adduct is determined by the chemical structure of the raw materials used, the mode of addition, the structure of the adduct, and the ratio of the epoxy resin to the amine compound added. With their proper choice,
According to the purpose, it is possible to synthesize an adduct having a low melting point to a high melting point. The higher the melting point, the easier it is to handle,
Conversely, the curing reaction initiation temperature of the formulation increases. Therefore, although the melting point has not been lowered from the viewpoint of curability, a melting point of at least 50 ° C. is required in consideration of handleability, especially handling in summer.

The amine compound / epoxy compound adduct is
Usually, it is synthesized under the condition of equivalence or amine excess,
When a monofunctional epoxy compound is used, the melting point of the resulting adduct decreases when the epoxy content is excessive. Conversely, when a polyfunctional epoxy compound is used, if the epoxy content is excessive, the addition reaction and the polymerization reaction occur competitively, and the melting point of the adduct increases. The reaction equivalent ratio between the epoxy compound and the amine compound in producing the amine compound / epoxy compound adduct in the present invention is not particularly limited, but is based on the stoichiometric amount.

In the case of obtaining pulverized adduct particles according to one embodiment of the present invention, when reacting the amine compound with the epoxy compound in the absence or presence of a solvent, a further excess amount may be used based on the above-mentioned ratio. After reacting the polyfunctional epoxy compound to form an amine compound / epoxy compound adduct in which the portion of the polymerized epoxy resin formed by the polyfunctional epoxy compound is mixed,
The solvent is removed from the reaction system, and the obtained adduct is pulverized and classified to obtain desired adduct particles. In the case of obtaining pulverized adduct particles according to another embodiment, after the amine compound / epoxy compound adduct is generated, the adduct obtained by removing the solvent from the reaction system is pulverized and classified. Adduct particles are obtained, and the obtained particles are further redispersed in a solvent and reacted with a further polyfunctional epoxy compound to form a polymer formed by the polyfunctional epoxy compound on the surface of the adduct particles. An encapsulation layer is formed.

The amount of the additional polyfunctional epoxy compound varies depending on the particle size of the adduct particles to be finally formed, but is generally 1 to 100 parts by weight based on 100 parts by weight of the adduct. Parts by weight, preferably 5 to 50 parts by weight. When the amount is less than 1 part by weight, the potential as a latent curing agent for epoxy resin is not sufficient, and the storage stability of the one-pack type epoxy resin curable composition to which such a curing agent is added becomes insufficient. On the other hand, if it exceeds 100 parts by weight, the low-temperature curability is impaired, which is not practical.

Such a further multifunctional epoxy compound which forms a mixed portion or an encapsulating layer by a polymerized epoxy resin may be a polyfunctional one, and many epoxy compounds which react with an amine compound to form an adduct. When it is a functional epoxy compound, it may be the same as the epoxy compound forming the adduct, or may be a different type. As described above, the time at which such a further polyfunctional epoxy compound is added is, as described above, before the start of the adduct formation reaction (that is, the step of charging the reaction raw materials), during the adduct formation reaction, after the end of the adduct formation reaction, The adduct formed by removing the solvent may be taken out, pulverized and classified to form particles having a desired particle size.

The reaction between the amine compound and the epoxy compound is carried out without a solvent or in a reaction solvent. However, from the viewpoint of removal of heat of reaction and uniform reaction, a method performed in a solvent is desirable. The solvent used for such purpose is well known in the art, and may be any single or mixed solvent in which both the amine compound and the epoxy compound are soluble. For example,
Examples include ethanol, n-butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, ethyl acetate, n-butyl acetate, cellosolve, benzene, toluene, xylene and the like.

By removing the reaction solvent after completion of the adduct formation reaction, the formed adduct is first obtained in the form of a mass. The removal of the solvent is performed by a vacuum evaporation method under heating. Next, the obtained bulk adduct is pulverized and classified to obtain adduct particles having a predetermined particle size.
The pulverization of the adduct is performed by first pulverizing with a cutter mill or a pin mill, and then finely pulverizing with a jet pulverizer or a centrifugal classification mill to a particle diameter of several μm. The classification of the adduct particles is performed by a dry centrifugal air classifier such as a sieve or an air separator or a micron separator,
The desired average particle size is taken out. The solvent used when the adduct particles pulverized and classified in this step are further redispersed in a solvent may be the same as or different from the solvent used in the adduct formation reaction. As such a solvent for redispersion, a solvent that does not show solubility in the adduct is used. For example, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, ethyl acetate, n-butyl acetate, benzene, toluene, xylene, cyclohexane, n-hexane and the like can be used. Further, in the solvent, the adduct particles may be subjected to mechanical high-speed stirring in order to stably redisperse avoiding sedimentation / aggregation, or to appropriately add a polymer dispersion stabilizer described below. Good.

The most important feature of the present invention resides in reacting a carboxylic acid compound with the formed amine compound / epoxy compound adduct. The carboxylic acid compound may act at any stage as long as it is before the polyfunctional isocyanate described below reacts with the adduct particles. For example, when a carboxylic acid compound is allowed to act after formation of an amine compound / epoxy compound adduct,
After completion of the adduct formation reaction and before removing the reaction solvent used in the reaction, a carboxylic acid compound can be added to the reaction system to further perform the reaction. Alternatively, after removing the solvent, removing the adduct, pulverizing and classifying the adduct, the adduct is redispersed in a solvent, and the reaction can be carried out by adding a carboxylic acid compound thereto. Further, after the pulverized and classified adduct particles are redispersed in a solvent to react with a further polyfunctional epoxy compound, a carboxylic acid compound may be added to the reaction system to cause a reaction.

By such a reaction, the curing reaction starting temperature of the obtained curing agent particles can be lowered, and low-temperature rapid curability can be provided. As the carboxylic acid compound used for this purpose, all kinds can be used. Any of a monofunctional carboxylic acid compound and a polyfunctional carboxylic acid compound can be used, and any of an aliphatic, alicyclic and aromatic carboxylic acid compound can be used. As specific examples, monofunctional aliphatic carboxylic acid compounds include acetic acid, trimethylacetic acid, propionic acid, n-butyric acid, isobutyric acid, 2-methylbutyric acid, n-valeric acid, isovaleric acid, and 3-methyl Valeric acid, hexanoic acid, 2-ethylhexanoic acid, octanoic acid, n-decanoic acid, lauric acid, and bifunctional aliphatic carboxylic acid compounds include tartaric acid, malonic acid, methylmalonic acid, dimethylmalonic acid, and succinic acid. , Methyl succinic acid,
2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, glutaric acid, 2-methylglutaric acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, monofunctional alicyclic carboxylic acid compounds include , Cyclopropane carboxylic acid,
Examples of 1-methylcyclopropanecarboxylic acid, cyclobutanecarboxylic acid, cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cycloheptanecarboxylic acid, and bifunctional alicyclic carboxylic acid compounds include 1,1-cyclobutanedicarboxylic acid, -Cyclohexanedicarboxylic acid,
1,4-cyclohexanedicarboxylic acid, hexahydro-
4-Methylphthalic acid and aromatic carboxylic acid compounds include benzoic acid, pt-butylbenzoic acid, o-benzoylbenzoic acid, toluic acid, phthalic acid, isophthalic acid, salicylic acid, phenylacetic acid, diphenylacetic acid, p-methoxy Phenylacetic acid, phenoxyacetic acid, protocatechuic acid,
Benzic acid, trimellitic anhydride and the like. One or two or more of these can be used in combination, but those which are soluble in the solvent used in the reaction system to be added must be selected. The amount of the carboxylic acid compound added to the adduct depends on the types of the adduct and the carboxylic acid compound, but is generally 1 to 200% by weight, preferably 5 to 100% by weight.

When the above treatment is carried out, the amine compound / epoxy compound treated with a carboxylic acid compound and having a polymerized epoxy resin portion or a polymerized epoxy resin encapsulating layer formed by an excess amount of a polyfunctional epoxy compound Adduct particles are obtained.

After the particles have been formed, a polyfunctional isocyanate compound is further reacted to form an encapsulating layer on the surface of the formed particles with the polyfunctional isocyanate compound, or to form a mixed layer with the polymerized epoxy resin. A wrapping layer is formed. Unless such an encapsulation layer is formed,
The potential of hardener particles cannot be expected.

Examples of the polyfunctional isocyanate compound used for this purpose include mononuclear and polynuclear products of toluene diisocyanate and methylene diphenyl diisocyanate, hydrogenated methylene diphenyl diisocyanate, 1,5-naphthalenediisocyanate, isophorone diisocyanate and hexamethylene diisocyanate. , Xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethyl xylylene diisocyanate, 1,3,6-hexamethylene triisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanatephenyl) thiophosphate, and other activities Examples include a polyfunctional isocyanate compound generated by an addition reaction with a hydrogen-containing compound.
Such an isocyanate compound is selected from those which dissolve in a solvent used when the adduct particles are redispersed, and one type or a combination of two or more types is used. The amount added to the adduct particles depends on the particle size of the adduct particles,
For particles having a volume average particle diameter in the range of 0.05 μm to 100 μm, 0.1 to 100 parts by weight of the adduct particles are used.
100 parts by weight, preferably 1 to 50 parts by weight. If the amount is less than 0.1 part by weight, sufficient storage stability cannot be obtained. If the amount exceeds 100 parts by weight, a considerably long reaction time is required, and the curing reactivity is lowered.

As described above, in another embodiment, the present invention dissolves both the amine compound and the epoxy compound in the presence of a dispersion stabilizer, and dissolves both the amine compound and the epoxy compound. When the adduct to be produced is reacted in an organic solvent that does not dissolve to produce adduct particles having a spherical shape, is a further polyfunctional epoxy compound present during the reaction between the amine compound and the epoxy compound? Alternatively, after the completion of the reaction, a further polyfunctional epoxy compound is added to further react,
After forming an amine compound / epoxy compound adduct spherical particle having an encapsulating layer formed by a polyfunctional epoxy compound on its surface, a further polyfunctional isocyanate compound acts on the resulting adduct spherical particle. In this case, the shape synthesized from the amine compound and the epoxy compound has a spherical encapsulant, and further has an encapsulating layer formed of an epoxy resin on the surface of the adduct, and further has a polyfunctional isocyanate compound on the epoxy encapsulating layer. A method for producing spherical adduct particles having an encapsulating layer formed by the above, or a mixed encapsulating layer of the both, wherein at any time before reacting the polyfunctional isocyanate compound, the adduct particles The present invention relates to a method characterized by reacting a carboxylic acid compound.

The amine compound, epoxy compound, further polyfunctional epoxy compound, polyfunctional isocyanate compound and carboxylic acid compound used in this embodiment of the present invention include those used in the production of the above-mentioned pulverized adduct particles. Can be used in an amount ratio equivalent to the amount used in the case of producing the pulverized adduct particles.

The formation of the amine compound / epoxy compound spherical adduct particles in this embodiment of the present invention can be realized only by the precipitation or dispersion addition reaction proposed by the present inventors in Japanese Patent Application No. 2-138176. is there. That is, the formation of the spherical adduct particles in such an embodiment of the present invention is carried out by selecting an amine compound and an epoxy compound as an organic solvent and dissolving the amine compound and the epoxy compound but not dissolving the obtained adduct. A stable dispersion without coagulation of the resulting adduct particles without causing agglomeration of the resulting adduct particles to obtain spherical amine compound / epoxy compound adduct particles having a controlled particle diameter by such a method. Can be. The most important factor in carrying out this reaction is the selection of a solvent used in the reaction. Basically, an amine compound and an epoxy compound as raw materials of the adduct and a dispersion stabilizer described below are dissolved,
It is necessary to use a solvent that precipitates the addition product as particles without dissolving it. Generally speaking, substances dissolve in solvents of similar polarity. Solubility parameter (unit: [cal / cm ³ ] ^1/2 ) as a measure of solvent polarity
Is often used. According to this display method, the epoxy compound, the amine compound, and the amine compound / epoxy compound adduct have solubility parameters of 8 to 11, 8 respectively.
It dissolves in the above and 11-16 solvents. Therefore, to carry out the precipitation or dispersion addition reaction of the present invention, a solvent having a solubility parameter of 8 to 11 is suitable.

Examples of the solvent used for the formation reaction of the spherical adduct particles in this embodiment of the present invention include methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, acetone, n-butyl acetate, isobutyl acetate, ethyl acetate, methyl acetate, and the like. Examples include tetrahydrofuran, 1,4-dioxane, cellosolve, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, anisole, toluene, p-xylene, benzene, cyclohexane, methylene chloride, chloroform, trichloroethylene, chlorobenzene, pyridine and the like. These are used alone or in combination of two or more. Even if the solubility parameter of the solvent is out of the range of 8 to 11, it is also possible to use the solvent after adjusting the solubility parameter within the range specified by a combination of two or more kinds. However, since a suitable solvent naturally differs somewhat depending on the chemical structures of the amine compound and the epoxy compound, it is important to select strictly according to each case.

In the precipitation or dispersion addition reaction in such an embodiment of the present invention, in order to stably disperse the precipitated adduct particles in a solvent to obtain spherical particles, it is necessary to coexist an appropriate dispersion stabilizer. If such a dispersion stabilizer is not present, the generated adduct particles will aggregate with each other during the reaction to cause phase separation, and the desired spherical particles cannot be obtained. As the dispersion stabilizer for this purpose, an amphiphilic polymer compound having a high affinity for both the formed adduct and the organic solvent is suitable. Alternatively, a polymer compound which does not initially show amphipathic properties but can be converted to amphiphilicity by a functional group conversion reaction may be used. In terms of chemical structure, it may be any of a graft copolymer, a block copolymer, a random copolymer, and another polymer.

Examples of the graft copolymer include poly ((methyl methacrylate-co-methacrylic acid) -g
-Styrene), poly ((methyl methacrylate-co-)
2-hydroxyethyl methacrylate) -g-styrene), poly ((methyl methacrylate-co-glycidyl methacrylate) -g-styrene), poly ((styrene-co-glycidyl methacrylate) -g-styrene), poly (2-hydroxy Ethyl methacrylate-g
-Styrene), poly (2,3-dihydroxypropyl methacrylate-g-styrene), poly (acrylamide-2-methylpropanesulfonic acid-g-styrene), poly (vinyl acetate-g-styrene), poly (methacrylic acid- g-styrene), poly (acrylamide-g-styrene), poly (ethylene oxide-g-styrene), poly (4-vinyl-N-ethylpyridium bromide-g-styrene), poly ((methyl methacrylate-co-methacryl) Acid) -g-alkyl methacrylate (R = C ₁ -C
₁₂ )), poly ((methyl methacrylate-co-fluoroalkyl acrylate) -g-methyl methacrylate), poly ((methyl methacrylate-co-glycidyl methacrylate) -g-methyl methacrylate), poly ((styrene-co-glycidyl methacrylate) )-
g-methyl methacrylate), poly (vinyl alcohol-g-methyl methacrylate), poly ((methyl methacrylate-co-glycidyl methacrylate) -g-methacrylic acid), poly (butadiene-g-methacrylic acid), poly (methyl methacrylate) g-2-hydroxyethyl methacrylate), poly (methyl methacrylate-gN-methylolacrylamide), poly (2-
Hydroxyethyl methacrylate-g-N-methylolacrylamide), poly (methyl methacrylate-g-)
12-hydroxystearic acid), poly ((ethyl acrylate-co-methacrylic acid) -g-12-hydroxystearic acid), poly ((methyl acrylate-co
-Methacrylic acid) -g-12-hydroxystearic acid), poly ((styrene-co-methacrylic acid) -g-
12-hydroxystearic acid), poly ((ethyl acrylate-co-methacrylic acid) -g-lauryl methacrylate), poly (vinyl acetate-g-2-ethylhexyl acrylate), poly (chloroprene-g-2-ethylhexyl acrylate) and the like Is mentioned.

Examples of the block copolymer include poly (vinyl acetate-b-styrene) and poly (styrene-b-styrene).
Dimethylsiloxane), poly (styrene-b-methacrylic acid), poly (lauryl methacrylate-b-methacrylic acid), poly (ethylene oxide-b-styrene-b-
Ethylene oxide), poly (12-hydroxystearic acid-b-ethylene oxide-b-12-hydroxystearic acid) and the like.

Examples of the random copolymer include poly (vinyl acetate-co-vinyl alcohol), poly (N-vinyl pyrrolidone-co-vinyl acetate), poly (N-vinyl pyrrolidone-co-methyl methacrylate), Poly (long chain methacrylate or acrylate-c
o-N-vinylpyrrolidone) and the like. Furthermore,
Examples of other polymers include carboxylic acid-modified polyphthalic acid glycol ester and quaternized amine-modified polyester.

As described above, there are various types of dispersion stabilizers used in this embodiment of the present invention in terms of structure, and there are various types of molecular weights from low molecular weight to high molecular weight.
The dispersion stabilizing effect on the generated adduct particles is, of course,
It depends on the chemical structure of the amine compound / epoxy compound and the nature of the solvent. In practice, it requires trial and error selection. Of course, these dispersion stabilizers may be used alone or in combination of two or more depending on the purpose.

In this embodiment of the present invention, first, in the spherical adduct particle forming reaction between the amine compound and the epoxy compound, the presence of a further excess of the multifunctional epoxy compound causes the multifunctional epoxy compound to be present on the surface thereof. An amine compound / epoxy compound spherical adduct particle having an encapsulating layer of a polymerized epoxy resin formed by an epoxy compound is obtained.

The further polyfunctional epoxy compound forming the encapsulating layer may be a polyfunctional epoxy compound, and the epoxy compound which reacts with an amine compound to form an adduct is a polyfunctional epoxy compound. May be the same as or different from the epoxy compound forming the adduct. As described above, the timing of adding the further polyfunctional epoxy compound is, as described above, before the start of the spherical adduct particle formation reaction (that is, the step of charging the reaction raw materials), during the spherical adduct particle formation reaction, during the spherical adduct particle formation reaction. Any of after the completion of the particle forming reaction may be used. When the epoxy compound for forming an adduct and the multifunctional epoxy compound for forming an encapsulation are the same, the encapsulating layer of the present invention can also be formed by using an excess amount of the epoxy compound in advance in the reaction between the amine compound and the epoxy compound. Can be produced.

The timing of reacting the resulting amine compound / epoxy compound spherical adduct particles with the carboxylic acid compound may be any stage before the reaction between the polyfunctional isocyanate compound and the spherical adduct particles. Is also good. For example, as an epoxy compound to be reacted with an amine compound to form an adduct, a reaction is carried out using an excess amount of a polyfunctional epoxy compound, and a polymerization formed by an excess of the polyfunctional epoxy compound on its surface. When forming amine compound / epoxy compound spherical adduct particles having an encapsulating layer of an epoxy resin, the carboxylic acid compound is added to the reaction system before the reaction of the amine compound and the epoxy compound is started or after the reaction is completed by 100%. It can be added and reacted. Further, when an amine compound and an epoxy compound are reacted to form spherical adduct particles, and then a polyfunctional epoxy compound is added and reacted to form an encapsulating layer of a polymerized epoxy resin on the spherical particles. The carboxylic acid compound may be added and reacted either after the formation of the particles or after the formation of the encapsulating layer.

By such a reaction, the curing reaction starting temperature of the obtained spherical curing agent particles can be lowered, and low-temperature rapid curability can be imparted.

In this embodiment of the present invention, as in the case of obtaining the above-mentioned pulverized adduct particles, the polyfunctional isocyanate compound is further reacted with the adduct spherical particles after the above steps are completed. Then, an encapsulating layer is formed on the surface of the generated particles with a polyfunctional isocyanate compound, or a mixed encapsulating layer with a polymerized epoxy resin is formed. Unless such an encapsulating layer is formed, the potential of the curing agent particles cannot be expected.

The polyfunctional isocyanate compound used here may be the same as that used to obtain the above-mentioned pulverized adduct particles, and may be used in the same quantitative ratio.

In the formation reaction of the spherical adduct and the hardener particles according to the embodiment of the present invention, the addition reaction and the modification reaction with the carboxylic acid compound are avoided by selecting an appropriate solvent and a dispersion stabilizer to avoid the formation of aggregates. And the encapsulating layer forming reaction by the polyfunctional epoxy compound or the polyfunctional isocyanate compound can smoothly proceed up to a reaction rate of 100%, but a stable progression in which no aggregate is formed and the adduct formed Control of the particle size of the curing agent particles is important.

First, the stable reaction is governed by the concentration of the starting material, the concentration of the dispersion stabilizer, the reaction temperature, the stirring conditions and the reaction rate or the reaction time. In the formation reaction of the adduct particles, it is necessary to add an appropriate dispersion stabilizer in order to form a stable dispersion. The addition amount of the dispersion stabilizer is usually 1 to 40% by weight, preferably 5 to 30% by weight, based on the total amount of the amine compound and the epoxy compound. Even if a sufficient dispersion stabilizer is present, when the concentration of the raw material and the reaction temperature are increased, the rate of the addition reaction is increased, but aggregates are easily formed, and the system becomes unstable. Therefore, the concentration of the raw material is usually 2 to 40% by weight, preferably 5 to 30% by weight in the solvent, whereby a necessary amount of the above-mentioned solvent is added. The reaction temperature is usually 40 to 90 ° C, preferably 50 to 70 ° C.

The stability of the reaction system is further related to the stirring conditions and the reaction rate. The appropriate stirring speed differs depending on the composition, reaction conditions and the shape of the stirring blade, and cannot be stated unconditionally.However, too fast stirring promotes the formation of aggregates, while too slow stirring results in spherical particles. Not suitable for Trial and error experiments are required for each system, but usually 50 to 1000 rpm, preferably 100 to 1000 rpm.
Use 500 rpm. Although depending on the reaction conditions, in general, aggregates tend to be generated as the reaction rate increases. As described above, as described above, the higher the raw material concentration and the reaction temperature, the lower the concentration of the dispersion stabilizer, and the smaller the size of the adduct particles to be formed, the lower the reaction rate at which aggregates are formed. start. By adjusting the conditions, 1
It is possible to reach a conversion of 00%.

After the formation of the adduct particles has proceeded at a yield of 100%, the above-mentioned addition is carried out in the encapsulation layer forming reaction with a further polyfunctional epoxy compound or polyfunctional isocyanate compound and the modification reaction with a carboxylic acid compound. The reaction conditions (raw material concentration, reaction temperature) and stirring conditions used for the body formation reaction can be applied. However, since the encapsulating layer forming reaction with the polyfunctional isocyanate compound and the modification reaction with the carboxylic acid compound occur even at a low temperature, the reaction temperature is from room temperature to 90 ° C, preferably from 50 to 70 ° C. The reaction time of the encapsulating layer forming reaction and the modification reaction with the carboxylic acid compound varies depending on the amount of the polyfunctional epoxy compound, the polyfunctional isocyanate compound and the carboxylic acid compound used and the reaction temperature, and generally, the recovered curing agent The time required for the particle yield to reach 100% is defined as the end point of the reaction. Also, the reaction solution was analyzed by infrared spectroscopy,
The end point of the reaction can also be determined by quantifying the remaining amount of the unreacted substance. These reaction conditions can be applied to the case of the pulverized adduct particles.

The particle size of the resulting hardener particles is governed by the particle size of the adduct particles used and the amount of polyfunctional epoxy compound or polyfunctional isocyanate compound added.

The particle size of the adduct particles is governed by the types of the raw materials and the solvent, the reaction conditions, the chemical structure and molecular structure of the dispersion stabilizer, and the amount added. Critical of these factors are the chemical and molecular structure of the dispersion stabilizer. For example, in a precipitation or dispersion addition reaction of 2-methylimidazole and bisphenol A diglycidyl ether in methyl isobutyl ketone, poly ((methyl methacrylate-co-methacrylic acid) -g-styrene)
When the graft copolymer is used as a dispersion stabilizer, micron-sized particles are provided, whereas a quaternized amine-modified polyester dispersion stabilizer provides submicron-sized particles. Further, although depending on the chemical structure of the dispersion stabilizer, generally, the smaller the molecular weight of the dispersion stabilizer, the larger the particle size of the obtained adduct particles. Next, the reaction conditions have a great influence on the formation of particles. Generally speaking, the higher the concentration of the dispersion stabilizer, the higher the reaction temperature and the higher the stirring speed, and the lower the concentration of the raw material and the conversion, the smaller the particles produced. When these factors are appropriately combined, the volume average particle diameter of the adduct particles to be formed is set to 0.1.
It can be controlled from 0.05 to 100 μm.

After the formation of the adduct particles having a desired particle size, an encapsulating layer is formed on the surface of the adduct particles by further adding a polyfunctional epoxy compound and a polyfunctional isocyanate compound. The polyfunctional epoxy compound is polymerized on the particle surface by the catalytic action of the adduct to form a polymerized epoxy resin film. In addition, the polyfunctional isocyanate compound reacts with hydroxyl groups, adsorbed moisture and other active hydrogen functional groups present on the surface of the adduct particles to be converted into a polymer such as polyurethane or polyurea to form an encapsulated film. It is thought that. Therefore, by forming these encapsulating layers, the volume average particle diameter of the obtained latent curing agent becomes larger than the volume average particle diameter of the original adduct particles.

Since the thickness of the encapsulating layer is determined by the volume average particle diameter of the adduct particles before the reaction and the amount of the polyfunctional epoxy compound or the polyfunctional isocyanate compound used for the surface reaction, the final thickness is obtained. The volume average particle size of the obtained curing agent is also controlled by these factors. For the range of the volume average particle diameter of the adduct particles, the excess addition amount of the polyfunctional epoxy compound and the addition amount of the polyfunctional isocyanate compound, the volume average particle diameter of the obtained curing agent of the present invention is: 0.1 to 200 μm.

The volume average particle diameter referred to here is the value described in “6.3.
It refers to the volume-based mean Stokes diameter of particles obtained by gravity or centrifugal sedimentation method shown in Section 4 and Sections 6 ・ 3 ・ 6 (hereinafter simply referred to as “volume-average particle diameter”).

A predetermined amount of a solvent was charged into a reactor, and the selected amine compound, epoxy compound and dispersion stabilizer were dissolved therein. The mixture was heated to a predetermined temperature while stirring and continued to be heated. The reaction solution becomes opaque with the formation of the adduct particles. As the reaction proceeds, the opacity of the system gradually increases, and the milky white color peculiar to the dispersion comes to appear. At this stage, when the amount ratio of the amine compound to the epoxy compound is equivalent, the amine compound / epoxy compound adduct spherical particles are formed, and the polyfunctional epoxy compound is used for the amine compound. In addition, when the equivalent of the polyfunctional epoxy compound is in excess, the spherical adduct particles having an encapsulating layer formed by the polyfunctional epoxy compound on the surface of the amine compound / epoxy compound adduct spherical particles are formed. It is formed. In the former case, the encapsulation layer of the polyfunctional epoxy compound can be formed on the surface of the adduct particles by adding and mixing a further polyfunctional epoxy compound at this point and continuing the reaction. . Further, after the formation of the adduct and the formation of the encapsulating layer, a polyfunctional isocyanate compound is added to continue the reaction, whereby the encapsulating layer of the polyfunctional epoxy compound is coated on the encapsulating layer of the polyfunctional epoxy compound. An encapsulating layer or a mixed encapsulating layer of the both can be further formed. By adding the carboxylic acid compound at any stage before or after the adduct particle formation reaction or before the formation reaction of the encapsulating layer with the polyfunctional isocyanate compound, the carboxylic acid compound can be added to the surface of the adduct particle or the polyfunctional isocyanate compound. From the surface of the encapsulating layer with the conductive epoxy compound, it penetrates into the particles on a molecular level and undergoes a modification reaction with the adduct (which is considered to form an ion complex), lowering the melting point of the curing agent particles, It is considered that quick curing can be provided. In addition, it contributes to the formation reaction of the encapsulating layer by the subsequent polyfunctional isocyanate compound, and can form a stronger encapsulating layer, and can further improve the solvent resistance and the potential of the curing agent particles.

After the completion of these reactions, the dispersion is cooled to room temperature and spray-dried with a spray drier for an organic solvent, or is collected by forced sedimentation and dried to obtain the desired powder of spherical hardener particles. Is obtained immediately.

Recovery of hardener particles by spray drying is most efficient. By using a cooling device attached to the spray dryer, almost 100% of the solvent used in the reaction can be recovered and can be recycled for the next reaction. Therefore, one of the major features of this process is that almost no solvent is used for the raw material cost. When a spray dryer is not used, the hardener particles are dispersed quite stably in the solvent and the particle size is small, so that it is extremely difficult to recover the particles by a normal filtration method or a natural sedimentation method. In this case, a hardening agent particle can be separated from the solvent by adding a solvent exhibiting an aggregating action to the dispersion system, coagulating and sedimenting the dispersed particles, and filtering or centrifuging. Further drying at a predetermined temperature can recover almost 100% of the particles. The solvent used can be reused by fractional distillation in the same manner as in the spray drying method.

Hereinafter, the present invention will be described in more detail with reference to Comparative Examples and Examples.

The fine particles of the hardener particles used in Comparative Examples and Examples were prepared by the following method. In order to examine the properties of the obtained curing agent particles as an epoxy resin curing agent, it was blended with Epicoat 828, which is a general-purpose epoxy resin, so as to have substantially the same amine concentration, and was uniformly kneaded in a mortar to obtain a cured composition. In order to examine the properties of the high-temperature curing type curing agent as a curing accelerator, Epicoat 828 was used.
To prepare a cured composition. At that time, dicyandiamide (Dicy) and methylhexahydrophthalic anhydride (MHHPA) were used as a high-temperature curing type curing agent,
The amounts added were 8 phr and 85 phr, respectively.

For the cured composition, the initial viscosity at 25 ° C.
The curing time at each temperature and the viscosity increase factor after storage at 40 ° C. for one week were measured. Further, a part of the cured composition was heated and cured at 100 ° C. for 1 hour and then at 150 ° C. for 3 hours to prepare a cured product, and its glass transition temperature (Tg) and water absorption in boiling water were measured. Further, a part of the sample was applied to an adherend aluminum, and the tensile shear adhesive strength after curing at 80 ° C. for 600 minutes was measured.

The measuring method or the apparatus used was as follows.

Viscosity : B type viscometer (Tokyo Keiki Co., Ltd.).

Curing time : The sample was placed on an aluminum plate for about 0.
1 g of the mixture was dropped, placed in a ventilation circulation oven previously adjusted to a predetermined temperature, heated and cured, and the time required to develop a hardness of H or more in a pencil hardness test was measured.

Tg : Measured by a penetration method using a thermomechanical analyzer (TMA, manufactured by Seiko Denshi Kogyo KK).

Boiling water absorption : about 40 mm in diameter and about 4 m in thickness
m was immersed in boiling water at 100 ° C. for 1 hour, and the weight increase was measured.

Tensile shear adhesive strength : Measured according to JIS-K6850.

Comparative Example 1 600 g of xylene and 300 g of 2-methylimidazole (2MZ) were placed in a 3,000 ml four-necked round bottom flask equipped with a thermometer, a reflux condenser, a dropping funnel and a steel propeller type stirring device. (3.654 eq.), And the temperature was increased to 120 ° C. while stirring to completely dissolve 2MZ. Then, while stirring, 68 g of xylene was added to 300 g of xylene.
A solution of 0 g of a bisphenol A diglycidyl ether type epoxy resin having an epoxy equivalent of 186 (manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat 828, abbreviated as “EP828”, 3.656 equivalents) was dissolved at a temperature of 120 ° C.
Was added from the dropping funnel over 90 minutes. Since the produced adduct was insoluble in xylene, it was deposited as a viscous candy with the progress of the reaction. The reaction was continued for another 2 hours, and the conversion reached almost 98% or more. Next, the temperature of the content was lowered to room temperature to stop stirring, the xylene in the upper layer was removed by a gradient method, and then the content of the flask was heated to 140 ° C. to remove residual xylene by 10 mm.
Distilled off under reduced pressure of Hg. Next, the molten adduct was poured into a shallow dish and cooled at room temperature to obtain a red-brown adduct mass. This was crushed with a hammer, crushed repeatedly with a jet mill, and finally classified to obtain a yellow fine powder. The volume average particle diameter of the fine powder was measured by an ultracentrifugal automatic particle size distribution analyzer (manufactured by HORIBA, Ltd., CAPA-700), and it was 2.9 μm.

Comparative Example 2 325 g of methyl isobutyl ketone (MIBK) was placed in a 1,000-ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel and a steel propeller-type stirrer.
And 162.5 g of 2-phenylimidazole (2PZ)
(0.4514 equivalents) and the temperature was increased to 10 while stirring.
The temperature was raised to 0 ° C. to completely dissolve 2PZ. Next, a solution prepared by dissolving 195.2 g of bisphenol A diglycidyl ether having an epoxy equivalent of 173 (manufactured by Dow Chemical Co., Ltd., DER332, 0.4514 equivalent) in 195 g of MIBK while stirring was added while maintaining the temperature at 100 ° C.
Added via dropping funnel over 0 minutes. Since the produced adduct was insoluble in MIBK, it was precipitated as a viscous candy with the progress of the reaction. The reaction was continued for another 4 hours, and the conversion reached almost 98% or more. Next, the temperature of the contents was lowered to room temperature to stop stirring, and the upper MIB
After removing K by a decanting method, the content of the flask was
The mixture was heated to 140 to 140 ° C., and the remaining MIBK was distilled off under a reduced pressure of 10 mmHg. Next, the molten adduct was poured into a shallow dish and cooled at room temperature to obtain a brown adduct mass. This was ground and classified in the same manner as in Comparative Example 1 to obtain a yellow fine powder, and the volume average particle diameter of the particles was 4.5 μm.

Comparative Example 3 In a 500 ml beaker equipped with a thermometer, a band heater and a steel propeller type stirring device, 276.8 g was placed.
Of DER332 (1.60 equivalents) was heated with a band heater while stirring the contents. Content temperature is 7
When the temperature reaches 0 to 75 ° C, the heating is stopped and the liquid 2-
Ethyl-4-methylimidazole (EMI-24) 17
6.3 g (1.60 equivalents) are added at once, and 500 rpm
The contents were uniformly mixed while stirring at a high speed. The temperature of the contents once dropped to about 60 ° C., but shortly thereafter, heat generation due to the addition reaction was observed, and the temperature rapidly increased to 23 ° C.
The temperature reached about 0 ° C. When the temperature was lowered gradually to 140 ° C while stirring the contents, the adduct formed became a viscous candy, which was poured into a shallow dish and cooled to room temperature to obtain a red-brown adduct mass. Was. This was ground and classified in the same manner as in Comparative Example 1 to obtain a yellow fine powder, and the volume average particle diameter of the particles was 4.3 μm.

In the reactions of Comparative Examples 1 to 3, the amine compound / epoxy compound adduct particles are synthesized stoichiometrically in a solvent or in a solvent-free state, and subsequently obtained by solvent removal, pulverization, and classification. It is a crushed product and has not undergone any modification reaction.

Comparative Example 4 275 g of MIBK and 137.5 g of 2phenylimidazole (2PZ , 0.382 equivalents), and the temperature was increased to 100 ° C. with stirring to completely dissolve 2PZ. Then, 137.5 g of a 30% MIBK solution of 2-ethylhexanoic acid was added dropwise from the funnel while stirring was continued, and after the addition was completed, the mixture was further stirred at the same temperature for 30 minutes. In addition, 1
655.2 g of DER332 (0.
(382 equivalents) was added from a dropping funnel over 30 minutes while maintaining the temperature at 100 ° C. Since the produced adduct was insoluble in MIBK, it was precipitated as a viscous candy with the progress of the reaction. The reaction was continued for another 4 hours, and the conversion reached almost 98% or more.
Next, the temperature of the content was lowered to room temperature to stop stirring, and the MIBK in the upper layer was removed by a gradient method.
Distilled off under reduced pressure of mHg. Next, the molten adduct was poured into a shallow dish and cooled at room temperature to obtain a tan adduct mass. This was ground and classified in the same manner as in Comparative Example 1 to obtain a yellow fine powder, and the volume average particle diameter of the particles was 5.2 μm.

In this reaction, 2PZ / DER33
The di-adduct particles were synthesized stoichiometrically in a solvent in the same manner as in Comparative Example 2, and subsequently obtained by removing the solvent, pulverizing, and classifying. However, the adduct was modified by adding 14% by weight of the carboxylic acid compound to the adduct before starting the addition reaction.

Comparative Example 5 210.6 g of a beaker having an internal volume of 500 ml equipped with a thermometer, a band heater and a steel propeller type stirring device were added.
Of DER332 (1.2173 equivalents) was heated with a band heater while stirring the contents. When the temperature of the contents reached 70-75 ° C., stop heating and add 89.4 g of EMI-24 (0.8115 equivalent) at once, add 4
The contents were uniformly mixed with high-speed stirring at 00 rpm. The temperature of the contents once dropped to about 60 ° C., but shortly thereafter, heat generation due to the addition reaction was observed, and the temperature rapidly rose to reach about 240 ° C. The adduct formed at the point when the temperature was gradually lowered to 170 ° C. while stirring the contents became a viscous candy, which was poured into a shallow dish, cooled to room temperature, and a yellow-brown adduct mass was formed. Obtained. This was ground and classified in the same manner as in Comparative Example 1 to obtain a yellow fine powder, and the volume average particle diameter of the particles was 5.4 μm.

In this reaction, EMI-24 / DE
The R332 adduct particles were synthesized in the same manner as in Comparative Example 3 in the absence of a solvent in the presence of an excess of a polyfunctional epoxy compound (31% by weight with respect to the stoichiometric adduct). It was obtained by classification.

Comparative Example 6 A beaker equipped with a thermometer, a band heater, and a steel propeller type stirring device having a capacity of 500 ml contained 210.6 g.
Of DER332 (1.2173 equivalents) was heated with a band heater while stirring the contents. When the temperature of the contents reaches 70 to 75 ° C, the heating is stopped and 2-ethyl-
89.4 g of 4-methylimidazole (EMI-24)
(0.8115 equivalents) was added all at once, and the contents were uniformly mixed with high-speed stirring at 400 rpm. The temperature of the contents once dropped to about 60 ° C., but shortly thereafter heat generation due to the addition reaction was observed, and the temperature rose rapidly to 240 ° C.
Rank has been reached. While stirring the content, the temperature was gradually lowered to 190 ° C., and 46.8 g of 2-ethylhexanoic acid was slowly dropped from the dropper. At 140 ° C., the adduct became a viscous candy. Was poured into a shallow dish and cooled to room temperature to obtain a tan adduct mass. This was ground and classified in the same manner as in Comparative Example 1 to obtain a yellow fine powder, and the volume average particle diameter of the particles was 5.8 μm.

In this reaction, EMI-24 / DE
The R332 adduct particles were synthesized in the same manner as in Comparative Example 3 in the absence of a solvent in the presence of an excess of a polyfunctional epoxy compound (31% by weight based on the stoichiometric adduct), and the addition reaction was terminated. Later, a carboxylic acid compound is added to the adduct for 2 hours.
The adduct was modified by adding 0% by weight, and finally pulverized and classified.

Comparative Example 7 A 1,000-ml three-necked round-bottomed flask equipped with a thermometer, a reflux condenser and a Teflon half-moon stirring device was charged with 2
8.0 g of 2-methylimidazole (2MZ, 0.34
Equivalent) and poly ((styrene-co-
4.54 g of glycidyl methacrylate) -g-methyl methacrylate) graft copolymer (Reseda GP-300, manufactured by Toagosei Co., Ltd.) was charged, and
After adding 3 g of MIBK, the temperature was raised to 70 ° C. to completely dissolve. Then 50% MIB of Epikote 828
125.60 g (0.34 equivalent) of the K solution was added, and the contents were reacted at 70 ° C. for 9 hours while stirring at a speed of 300 rpm. The reaction solution, which was initially colorless and transparent, gradually changed to a milky white and opaque liquid as the reaction time elapsed,
At the end of the reaction, a creamy milky white dispersion was obtained.

When the reaction rate reached 100% in the reaction at 70 ° C. for 9 hours, the reaction mixture was cooled to room temperature, spray-dried with a spray dryer for organic solvent system (manufactured by Yamato Scientific Co., Ltd., model GS-31), and cured. The particles were collected. The spray drying conditions were as follows.

Drying chamber inlet temperature: 100 ° C. Drying chamber outlet temperature: 74 ° C. Condenser outlet temperature: 16 ° C. Spray nozzle diameter: 0.4 mm Spray pressure: 1.2 kg / cm ² Hot air flow rate: 0.5 m ³ / min Rate: 10 g / min This spray drying yielded almost the theoretical amount of hardener particles as a white dry powder. Observation with a scanning electron microscope revealed that the hardener particles were recovered as almost primary particles. The volume average particle diameter of the obtained hardener particles was 2.8 μm as measured by an ultracentrifugal automatic particle size distribution analyzer (CAPA-700, manufactured by Horiba, Ltd.).
Met. The recovery rate of MIBK as a solvent is 99.
2%.

Comparative Example 8 A 1,000-ml three-necked round-bottomed flask equipped with a thermometer, a reflux condenser and a Teflon half-moon stirring device was prepared.
40.37 g of 2-phenylimidazole (2PZ,
0.280 equiv.) And 4.44 g of Reseda GP-300.
And then add 543.6 g of MIBK to it,
The temperature was raised to 70 ° C. to completely dissolve. Then DER3
96.88 g (0.280 equivalent) of a 50% MIBK solution of 32 was added, and the contents were reacted at 70 ° C. for 15 hours with stirring at a speed of 300 rpm. The initially colorless and transparent reaction liquid gradually turned into a milky white and opaque liquid as the reaction time passed, and became a creamy uniform and stable dispersion at the end of the reaction. The dispersion of the hardener particles thus synthesized was transferred to a 2,000 ml beaker, and about 50 ml of n-hexane was gradually added while stirring the contents.
The dispersed particles were coagulated and settled. The particles were separated by filtration through a glass filter and further dried under vacuum at 50 ° C. for 2 days to obtain a creamy white powder in a yield of 95.5%. The volume average particle diameter of the obtained curing agent particles was 3.8 μm.

In the reactions of Comparative Examples 7 and 8, the amine compound / epoxy compound adduct particles were spherical in a stoichiometric manner synthesized by precipitation or dispersion addition reaction in an organic solvent. No modification reaction was performed.

Comparative Example 9 A 1,000-ml three-necked round-bottomed flask equipped with a thermometer, a reflux condenser, and a Teflon half-moon type stirring device was prepared.
24.0 g of 2-methylimidazole and 3.90 g of Reseda GP-300 were charged into which 465.03 g of M were added.
After IBK was added, the temperature was raised to 70 ° C. to completely dissolve. Next, a 50% MIBK solution 1 of Epikote 828
07.66 g was added, and the contents were reacted at 70 ° C. for 9 hours while stirring at a speed of 300 rpm. To this, 51.01 g of a 50% MIBK solution of Epicoat 828 and 21.43 g of MIBK for washing were added, and further reacted at the same temperature for 4 hours to reach a reaction rate of almost 100%. At the end of the reaction, a uniform and stable dispersion that was almost the same in appearance as Comparative Example 7 was obtained. The dispersion of the curing agent particles thus synthesized was spray-dried under the same conditions as in Comparative Example 7 to quantitatively obtain a dried white powder. The volume average particle diameter of the obtained curing agent particles was 3.0 μm.

In this reaction, the hardening agent particles contained 100% of the same 2MZ / EP828 adduct particles as in Comparative Example 7.
, And then the polyfunctional epoxy compound was added in an amount of 33% by weight based on the adduct, and synthesized by a two-step method.

Comparative Example 10 A 1,000-ml three-necked round-bottomed flask equipped with a thermometer, a reflux condenser and a Teflon half-moon type stirring device was prepared.
40.37 g of 2-phenylimidazole (2PZ,
0.280 equiv.) And 4.44 g of Reseda GP-300.
And then add 543.6 g of MIBK to it,
The temperature was raised to 70 ° C. to completely dissolve. Then DER3
96.88 g (0.280 equivalents) of a 50% MIBK solution of 32 was added, and the contents were reacted at 70 ° C. for 18 hours with stirring at a speed of 300 rpm. The initially colorless and transparent reaction liquid gradually changed to a milky white and opaque liquid as the reaction time elapsed, and became a creamy uniform and stable dispersion. Add 50% MIBK solution 4 of Epikote 828
4.50 g and 20.0 g of MIBK for washing were added secondarily, and further reacted at the same temperature for 6 hours. At the end of the reaction, a cream-colored uniform and stable dispersion was obtained. The dispersion of the hardener particles thus synthesized was subjected to coagulation sedimentation and recovery of the dispersed particles with n-hexane in the same manner as in Comparative Example 8, the particles were separated by filtration through a glass filter, and further dried in vacuo at 50 ° C. for 2 days to form a cream. A colored white powder was obtained almost quantitatively. The volume average particle diameter of the obtained curing agent particles is 4.0.
μm.

In this reaction, the curing agent particles contained almost the same 2PZ / DER332 adduct particles as in Comparative Example 8,
After the synthesis with a yield of 00%, the polyfunctional epoxy compound was added in an amount of 25% by weight with respect to the adduct and synthesized by a two-step method.

Comparative Example 11 In a 1,000 ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon stirring device, 24.0 g of 2-methylimidazole (2M) was added.
Z, 0.29 eq) and 3.90 g of Reseda GP-30
0 was added, and 465.03 g of MIBK was added thereto, and then the temperature was increased to 70 ° C. to completely dissolve. Then, 107.66 g of a 50% MIBK solution of Epikote 828
(0.29 equivalents) was added, and the contents were reacted at 70 ° C. for 9 hours with stirring at a speed of 300 rpm. To this, 51.01 g of a 50% MIBK solution of Epicoat 828 and 21.43 g of MIBK for washing were added secondarily, and further reacted at the same temperature for 4 hours to reach a reaction rate of almost 100%. To this, 35.77 g of a 30% MIBK solution of 2-ethylhexanoic acid was slowly added dropwise from the funnel, and after the completion of the addition, the mixture was further reacted at the same temperature for 3 hours. At the end of the reaction,
The degree of whiteness increased in comparison with Comparative Example 7 in appearance, and a uniform and stable dispersion was obtained. The dispersion of the hardener particles thus synthesized was subjected to coagulation sedimentation and recovery of the dispersed particles with n-hexane in the same manner as in Comparative Example 8, the particles were separated by filtration through a glass filter, and further dried in vacuo at 40 ° C. for 2 days to obtain white. Powder was obtained. The volume average particle diameter of the obtained curing agent particles is 3.0 μm.
Met.

In this reaction, as in Comparative Example 9, the curing agent particles were prepared by adding a polyfunctional epoxy compound to 2MZ / EP8
After adding 33% by weight to 28 adducts and reacting in a two-stage method, a modification reaction of adduct particles with a carboxylic acid compound was performed. The amount of the carboxylic acid compound added was 14% by weight based on the adduct.

Comparative Example 12 In a 1,000 ml four-necked round bottom flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon stirring device, 40.37 g of 2-phenylimidazole (2PZ, 0.280 equiv.) And 4.44 g Reseda G
P-300 was charged, 543.6 g of MIBK was added thereto, and the temperature was increased to 70 ° C. to dissolve completely. Then, while stirring, 30% MIBK solution of isobutyric acid 4
0.37 g was added dropwise from the funnel, and after completion of the addition, the mixture was further stirred at the same temperature for 30 minutes. 50% MIB of DER332
96.88 g (0.280 equivalents) of the K solution was added, and the contents were reacted at 70 ° C. for 18 hours while stirring at a speed of 300 rpm. The initially colorless and transparent reaction liquid gradually changed to a milky white and opaque liquid as the reaction time elapsed, and became a creamy uniform and stable dispersion. To this, 44.50 g of a 50% MIBK solution of Epikote 828 and 20.0 g of MIBK for cleaning were added secondarily, and further added at the same temperature for 5 minutes.
Allowed to react for hours. At the end of the reaction, a creamy milky white uniform and stable dispersion was obtained. The dispersion of the hardener particles synthesized in this manner was treated with n-
The dispersed particles were subjected to coagulation sedimentation and recovery with hexane, the particles were separated by filtration through a glass filter, and further vacuum-dried at 45 ° C. for 2 days to obtain a creamy white powder almost quantitatively. The volume average particle diameter of the obtained curing agent particles is 4.2 μm.
Met.

In this reaction, as in Comparative Example 10, the curing agent particles were prepared by converting the polyfunctional epoxy compound to 2PZ / DE
It is obtained by adding 25% by weight to the R332 adduct and reacting in a two-stage method. However, before synthesizing the adduct particles, the adduct was modified by adding 14% by weight of the carboxylic acid compound to the adduct.

Example 1 A 1,000-ml four-necked round-bottom flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon stirring device was charged with an average particle diameter of 2 prepared in Comparative Example 1. 8.9 μm of 2MZ / EP828 adduct fine particles (80.0 g) were charged, and 530.03 g of cyclohexane and 6.0 g of a dispersion stabilizer Hypermer LP8 (40% of quaternized amine-modified polyester) were used as a dispersion stabilizer. % Toluene solution), the content was stirred at a speed of 400 rpm, the temperature was raised to 60 ° C., and the content was completely dispersed.
Add 50% MIBK solution 52.5 of Epikote 828
0 g was added dropwise from the funnel over a period of 60 minutes, and after the completion of the addition, the mixture was further reacted at the same temperature for 8 hours. To this, 36.80 g of a 30% cyclohexane solution of 2-ethylhexanoic acid was slowly added dropwise from the funnel, and after completion of the addition, the mixture was further reacted at the same temperature for 4 hours. Finally, a 10% cyclohexane solution of methylene diphenyl diisocyanate (MDI, manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MT) 82.7.
0 g is dropped from the funnel over a period of 120 minutes.
Further, the reaction was carried out at the same temperature for 20 hours, and the reaction rate was almost 100%.
Reached. At the end of the reaction, a uniform dispersion having a cream color was obtained. The dispersion of the hardener particles thus synthesized was transferred to a 2,000 ml beaker, allowed to settle overnight, and the particles were separated by filtration through a glass filter.
Vacuum drying at 5 ° C. for 2 days gave a pale yellow powder. The volume average particle diameter of the obtained curing agent particles was 3.2 μm.

In this example, the stoichiometric 2MZ / EP828 crushed adduct particles produced by the solution addition reaction of Comparative Example 1 followed by solvent removal, pulverization and classification were redispersed in a solvent. Then, a polyfunctional epoxy compound (33% by weight), a carboxylic acid compound (14% by weight) and a polyfunctional isocyanate compound (10% by weight) were added in this order to further carry out a reaction. Example 2 A 1,000-ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel, and a Teflon crescent-shaped stirring device was prepared to have an average particle size of 4.5 μm produced in Comparative Example 2. 80.0 g of fine powder of 2PZ / DER332 adduct particles was charged, 530.0 g of cyclohexane and 6.0 g of Hypermer LP8 were added as a dispersion stabilizer, and then the content was stirred at a speed of 400 rpm. Was raised to 50 ° C. and completely dispersed. To this, 36.34 g of a 30% solution of 2-ethylhexanoic acid in cyclohexane was slowly dropped from the funnel.
Allowed to react for hours. 50% MI of Epicoat 828
40.0 g of the BK solution was added dropwise from the funnel over a period of 60 minutes, and after the completion of the addition, the mixture was further reacted at the same temperature for 15 hours. Next, the temperature of the contents was raised to 60 ° C., and 10 g of methylene diphenyl diisocyanate (MDI, millionate MT) was added.
88.0 g of a% cyclohexane solution was added dropwise from the funnel over 120 minutes, and after the completion of the addition, the mixture was further reacted at the same temperature for 20 hours to reach a reaction rate of almost 100%. At the end of the reaction, a light yellow-brown homogeneous dispersion was obtained. The dispersion of the hardener particles thus synthesized was transferred to a 2,000 ml beaker, allowed to stand still overnight, the particles were filtered off with a glass filter, and further vacuum-dried at 45 ° C. for 2 days to obtain a pale yellow powder. Obtained. The volume average particle diameter of the obtained curing agent particles was 4.9 μm.

In this example, the stoichiometric 2PZ / DER332 crushed adduct particles produced by the solution addition reaction of Comparative Example 2, followed by solvent removal, pulverization and classification were redispersed in a solvent. Then, a carboxylic acid compound (14% by weight), a polyfunctional epoxy compound (25% by weight) and a polyfunctional isocyanate compound (11% by weight) were added in this order to further carry out a reaction.

Example 3 A 1,000-ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel, and a Teflon half-moon stirring device was charged with an average particle size of 5 produced in Comparative Example 4. 90.9 g of 2PZ / DER332 / 2-ethylhexanoic acid adduct fine particles of 9.
Of cyclohexane and 6.8 g of Hypermer LP8 as a dispersion stabilizer were added, and then the content was stirred at a speed of 400 rpm and the temperature was raised to 50 ° C. to completely disperse the contents. Add 50% MIBK solution 4 of Epikote 828
0.0 g was added dropwise from the funnel over a period of 60 minutes, and after the completion of the addition, the mixture was further reacted at the same temperature for 15 hours. Next, the temperature of the content was raised to 60 ° C., and 88.0 g of a 10% cyclohexane solution of methylene diphenyl diisocyanate (MDI, millionate MT) was added dropwise from the funnel over 120 minutes, and after the addition was completed, the reaction was continued at the same temperature for 20 hours. The reaction rate reached almost 100%. At the end of the reaction,
A uniform dispersion having a pale yellowish brown color was obtained. The dispersion of the hardener particles thus synthesized was transferred to a 2,000 ml beaker, allowed to stand still overnight, the particles were filtered off with a glass filter, and further vacuum-dried at 45 ° C. for 2 days to obtain a pale yellow powder. Obtained. The volume average particle diameter of the obtained curing agent particles is 5.4 μm.
m.

In this example, the curing agent particles were prepared by adding 14% by weight of a carboxylic acid compound before the synthesis of the stoichiometric 2PZ / DER332 adduct in a solvent, and removing the solvent, pulverizing after completion of the addition reaction. A product prepared by redispersing the crushed adduct particles produced by classification in a solvent, and further adding and reacting 25 wt% of a polyfunctional epoxy compound and 11 wt% of a polyfunctional isocyanate compound in this order. It is.

Example 4 275 g of MIBK and 2-phenylimidazole 1 were placed in a 1,000 ml four-neck round bottom flask equipped with a thermometer, a reflux condenser, a dropping funnel and a steel propeller-type stirrer.
37.5 g (2PZ, 0.382 equivalent) was charged, and the temperature was increased to 100 ° C. with stirring to completely dissolve 2PZ. Then, while stirring, 165 g of MIBK
A solution prepared by dissolving 165.2 g of DER332 (0.382 equiv.) Was added from the dropping funnel over 30 minutes while maintaining the temperature at 100 ° C. The generated adduct is MI
Due to insolubility in BK, it precipitated as a viscous candy with the progress of the reaction. The reaction was continued for another 4 hours, and the conversion reached almost 98% or more. To this, 41.3 g of 2-ethylhexanoic acid was added dropwise from the funnel, and after completion of the addition, the mixture was further stirred at the same temperature for 3 hours. Next, the temperature of the contents was lowered to room temperature to stop stirring, the MIBK in the upper layer was removed by a gradient method, and then the contents of the flask were heated to 100 to 140 ° C., and the remaining MIBK was reduced under a reduced pressure of 10 mmHg. Was distilled off. Next, the molten adduct was poured into a shallow dish and cooled to room temperature to obtain a tan adduct mass. Comparative Example 1
The powder was pulverized and classified in the same manner as described above to obtain a yellow fine powder, and the volume average particle diameter of the particles was 4.6 μm.

Fine powder 9 of the adduct particles produced above
0.9 g was again filled with a thermometer, a reflux condenser, a dropping funnel and a Teflon crescent-shaped stirring device having an internal volume of 1,000 m.
l to a four-necked round-bottomed flask,
Of cyclohexane and 6.8 g of Hypermer LP8 as a dispersion stabilizer were added, and then the content was stirred at a speed of 400 rpm and the temperature was raised to 50 ° C. to completely disperse the contents. Add 50% MIBK solution 4 of Epikote 828
0.0 g was added dropwise from the funnel over a period of 60 minutes, and after the completion of the addition, the mixture was further reacted at the same temperature for 15 hours. Next, the temperature of the content was raised to 60 ° C., and 88.0 g of a 10% cyclohexane solution of methylene diphenyl diisocyanate (MDI, millionate MT) was added dropwise from the funnel over 120 minutes, and after the addition was completed, the reaction was continued at the same temperature for 20 hours. The reaction rate reached almost 100%. At the end of the reaction,
A uniform dispersion having a pale yellowish brown color was obtained. The dispersion of the hardener particles thus synthesized was transferred to a 2,000 ml beaker, allowed to stand still overnight, the particles were filtered off with a glass filter, and further vacuum-dried at 45 ° C. for 2 days to obtain a pale yellow powder. Obtained. The volume average particle diameter of the obtained curing agent particles is 4.8 μm.
m.

In this example, the curing agent particles were reacted by adding 14% by weight of a carboxylic acid compound after the synthesis of the stoichiometric 2PZ / DER332 adduct in a solvent, followed by removal of the solvent, pulverization, A product prepared by redispersing the crushed adduct particles produced by classification in a solvent, further adding 25% by weight of a polyfunctional epoxy compound and 11% by weight of a polyfunctional isocyanate compound in order, and reacting. It is.

Example 5 A 1,000-ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel, and a Teflon half-moon stirring device was charged with an average particle size of 5 produced in Comparative Example 6. 20.0 μm of EMI-24 / DER332 / 2-ethylhexanoic acid adduct particles (100.0 g) were charged.
After adding 0.0 g of n-hexane, the content was
The temperature was raised to 40 ° C. while stirring at a high speed at a speed of rpm to completely disperse. To this, 69.0 g of 10% n-hexane of methylene diphenyl diisocyanate (MDI, millionate MT) was slowly added dropwise from a funnel over 4 hours. %. At the end of the reaction, a light yellow-brown homogeneous dispersion was obtained. The dispersion of the hardener particles thus synthesized was transferred to a 2,000 ml beaker, allowed to stand still overnight, the particles were filtered off with a glass filter, and further vacuum-dried at 45 ° C. for 2 days to obtain a pale yellow powder. Obtained. The volume average particle diameter of the obtained curing agent particles is 5.
It was 5 μm.

In this example, when the EMI-24 / DER332 adduct was synthesized in the absence of a solvent, the curing agent particles were used under conditions of an excess of 31% by weight of the polyfunctional epoxy compound. 20 carboxylic acid compounds
% By weight, followed by re-dispersing the crushed adduct particles produced by pulverization and classification in a solvent, and further adding and reacting 10% by weight of a polyfunctional isocyanate compound. It is something.

Example 6 A 1,000-ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon stirring device was charged with an average particle size of 5 produced in Comparative Example 5. Fine powder 8 of 4 μm EMI-24 / DER332 adduct particles
After 6.5 g was charged and 580.0 g of n-hexane was added thereto, the contents were completely dispersed by raising the temperature to 40 ° C. while stirring the contents at a high speed of 500 rpm. To this, 45.0% of 30% n-hexane of 2-ethylhexanoic acid.
g was slowly added dropwise from the funnel, and after completion of the addition, the mixture was further reacted at the same temperature for 5 hours. Next, 10% n of methylene diphenyl diisocyanate (MDI, millionate MT)
69.0 g of a hexane solution was slowly dropped from the funnel over 4 hours, and after the completion of the dropping, the mixture was further reacted at the same temperature for 24 hours to reach a reaction rate of almost 100%. At the end of the reaction, a light yellow-brown homogeneous dispersion was obtained. The dispersion of the hardener particles thus synthesized was transferred to a 2,000 ml beaker, allowed to stand still overnight, the particles were filtered off with a glass filter, and further vacuum-dried at 45 ° C. for 2 days to obtain a pale yellow powder. Obtained. The volume average particle diameter of the obtained curing agent particles was 5.8 μm.

In this example, the hardener particles were prepared by synthesizing an EMI-24 / DER332 adduct under a condition of an excess of 31% by weight of the polyfunctional epoxy compound in the absence of a solvent.
Subsequently, the crushed adduct particles produced by pulverization and classification are redispersed in a solvent, and 20% by weight of a carboxylic acid compound and 10% by weight of a polyfunctional isocyanate compound are sequentially added and reacted. It is something.

Example 7 In a 1,000 ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon stirring device, 24.0 g of 2-methylimidazole (2M) was added.
Z, 0.29 eq) and 3.90 g of Reseda GP-30
0 was added, and 465.03 g of MIBK was added thereto, and then the temperature was increased to 70 ° C. to completely dissolve. Then, 107.66 g of a 50% MIBK solution of Epikote 828
(0.29 equivalents) was added, and the contents were reacted at 70 ° C. for 9 hours with stirring at a speed of 300 rpm. To this, 51.01 g of a 50% MIBK solution of Epicoat 828 and 21.43 g of MIBK for cleaning were added secondarily, and the mixture was further reacted at the same temperature for 4 hours. To this, 3-ethylhexanoic acid 3
35.77 g of a 0% MIBK solution was slowly added dropwise from the funnel, and after completion of the addition, the mixture was further reacted at the same temperature for 3 hours. Finally, methylene diphenyl diisocyanate (MDI,
64.34 g of a 10% MIBK solution of (Millionate MT)
Was dropped from the funnel over 40 minutes, and after the completion of the dropping, the mixture was further reacted at the same temperature for 8 hours to reach a reaction rate of almost 100%. At the end of the reaction, a uniform creamy milky white dispersion was obtained. The dispersion liquid of the curing agent particles synthesized in this manner was treated with n-
The particles were subjected to coagulation sedimentation recovery with hexane and vacuum drying to obtain a dried white powder almost quantitatively. The volume average particle diameter of the obtained curing agent particles was 3.1 μm.

In this reaction, as in Comparative Example 11, 33% by weight of a polyfunctional epoxy compound was further added to the stoichiometric spherical particles of the 2MZ / EP828 adduct after completion of the addition reaction in the same manner as in Comparative Example 11. After reacting in a two-stage method, a carboxylic acid compound was added in an amount of 14% by weight to modify the adduct particles. However, finally, a treatment reaction was carried out with 8% by weight of a polyfunctional isocyanate compound.

Example 8 In a 1,000 ml four-neck round bottom flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon stirring device, 24.0 g of 2-methylimidazole and 3.
90 g of Reseda GP-300 was charged, and 465.
After adding 03 g of MIBK, the temperature was raised to 70 ° C. to completely dissolve. Then 50% MI of Epicoat 828
107.66 g of the BK solution was added, and the content was adjusted to 300 rpm.
The reaction was carried out at 70 ° C. for 9 hours while stirring at a speed of. Add 51.01 g of 50% MIBK solution of Epikote 828 to this
Then, MIBK 21.43 g for washing was added secondarily, and further reacted at the same temperature for 4 hours. To this, 71.50 g of a 30% MIBK solution of 2-ethylhexanoic acid was slowly added dropwise from the funnel, and after completion of the addition, the mixture was further reacted at the same temperature for 3 hours. Finally, methylene diphenyl diisocyanate (M
DI, millionate MT) in 10% MIBK 85.
80 g is dropped from the funnel over 60 minutes, and after the dropping is completed,
Further, the reaction was carried out at the same temperature for 9 hours to reach a reaction rate of almost 100%. At the end of the reaction, a uniform and stable dispersion which was almost the same in appearance as in Example 7 was obtained. The dispersion liquid of the curing agent particles synthesized in this manner was treated with n
-Coagulation sedimentation and recovery of particles with hexane and vacuum drying were performed to obtain a dried white powder almost quantitatively. The volume average particle diameter of the obtained curing agent particles was 3.2 μm.

In this reaction, the stoichiometric 2MZ
After synthesizing spherical particles of the adduct / EP828, 33% by weight of a polyfunctional epoxy compound was added to the adduct and reacted in a two-stage method.
The reaction was carried out with 11% by weight of a polyfunctional isocyanate compound.

Example 9 In a 1,000 ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon stirring device, 24.0 g of 2-methylimidazole (0. 2
92 eq.) And 3.90 g of Reseda GP-300 were added, and 528.52 g of MIBK was added thereto, and the temperature was increased to 70 ° C. to completely dissolve. Then, 158.67 g of a 50% MIBK solution of Epikote 828 (0.42
7 equivalents) and reacted at 70 ° C. for 10 hours while stirring the content at a speed of 300 rpm. To this, 71.50 g of a 30% MIBK solution of 2-ethylhexanoic acid was slowly added dropwise from the funnel, and after completion of the addition, the mixture was further reacted at the same temperature for 3 hours. Finally, 85.80 g of a 10% MIBK solution of methylene diphenyl diisocyanate (MDI, millionate MT) was added dropwise from the funnel over 60 minutes, and after completion of the addition, the mixture was further reacted at the same temperature for 9 hours.
00%. At the end of the reaction, a uniform and stable dispersion which was almost the same in appearance as in Example 8 was obtained. In the same manner as in Comparative Example 8, the dispersion liquid of the curing agent particles thus synthesized was subjected to coagulation sedimentation and recovery with n-hexane and vacuum drying to obtain a dried white powder almost quantitatively. The volume average particle diameter of the obtained curing agent particles is 3.2 μm.
Met.

In this reaction, 2MZ / EP828
When synthesizing spherical particles of the adduct, 33% by weight of a polyfunctional epoxy compound is added to the stoichiometric adduct and reacted in a one-step method.
% Of the polyfunctional isocyanate compound, and finally a treatment reaction was performed with 11% by weight of the polyfunctional isocyanate compound.

Example 10 In a 1,000 ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon stirring device, 24.0 g of 2-methylimidazole and 3.
90 g of Reseda GP-300 was charged, and 465.
After adding 03 g of MIBK, the temperature was raised to 70 ° C. to completely dissolve. Then 50% MI of Epicoat 828
107.66 g of the BK solution was added, and the content was adjusted to 300 rpm.
The reaction was carried out at 70 ° C. for 9 hours while stirring at a speed of. Add 51.01 g of 50% MIBK solution of Epikote 828 to this
Then, MIBK 21.43 g for washing was added secondarily, and further reacted at the same temperature for 4 hours. To this, 142.97 g of a 30% MIBK solution of 2-ethylhexanoic acid was slowly added dropwise from the funnel, and after completion of the addition, the mixture was further reacted at the same temperature for 3 hours. Finally, a 10% MI of a formalin condensate of methylene diphenyl diisocyanate (p-MDI, manufactured by Nippon Polyurethane Industry Co., Ltd., Millionate MR-300) is used.
107.20 g of the BK solution was added dropwise from the funnel over 2 hours, and after completion of the addition, the mixture was further reacted at the same temperature for 10 hours to reach a reaction rate of almost 100%. At the end of the reaction, a uniform and stable dispersion which was almost the same in appearance as in Example 7 was obtained. In the same manner as in Comparative Example 8, the dispersion liquid of the curing agent particles thus synthesized was subjected to coagulation sedimentation and recovery with n-hexane and vacuum drying to obtain a dried white powder.
The volume average particle diameter of the obtained curing agent particles was 3.3 μm.

In this reaction, the stoichiometric 2MZ
After synthesizing spherical particles of the adduct / EP828, 33% by weight of a polyfunctional epoxy compound was further added to the adduct and reacted in a two-stage method.
Then, the reaction was carried out with 14% by weight of the polyfunctional isocyanate compound.

Example 11 40.37 g of 2-phenylimidazole (2
PZ, 0.280 equivalents) and 4.44 g of Reseda GP-
300 were added, and 543.6 g of MIBK was added thereto, and the temperature was increased to 70 ° C. to completely dissolve. Then, while stirring, 30% MIBK solution of isobutyric acid 4
0.37 g was added dropwise from the funnel, and after completion of the addition, the mixture was further stirred at the same temperature for 30 minutes. 50% MIB of DER332
96.88 g (0.280 equivalents) of the K solution was added, and the contents were reacted at 70 ° C. for 18 hours while stirring at a speed of 300 rpm. 50% MIBK of Epicoat 828
44.50 g of the solution and 20.0 g of MIBK for washing
Next, the mixture was added and reacted at the same temperature for 5 hours. Finally, 10% MIBK of tolylene diisocyanate (TDJ, manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate T-100)
88.81 g of the solution was added dropwise from the funnel over a period of 60 minutes, and after completion of the addition, the mixture was further reacted at the same temperature for 10 hours to reach a reaction rate of almost 100%. At the end of the reaction, a creamy milky white uniform and stable dispersion was obtained. In the same manner as in Comparative Example 8, the dispersion of the hardener particles thus synthesized was subjected to coagulation, sedimentation and collection of the dispersed particles with n-hexane, and the particles were separated by filtration through a glass filter.
For 2 days to obtain a creamy white powder almost quantitatively. The volume average particle diameter of the obtained curing agent particles was 4.3 μm.

In this reaction, stoichiometric 2PZ
When synthesizing spherical particles of the / DER332 adduct, a carboxylic acid compound is added to the adduct at 14% by weight before the addition reaction is started, and a polyfunctional epoxy compound is further added at 25% by weight after the end of the addition reaction. Finally, a treatment reaction was performed with 10% by weight of the polyfunctional isocyanate compound.

Example 12 40.37 g of 2-phenylimidazole (2) was placed in a 1,000 ml four-necked round-bottomed flask equipped with a thermometer, a reflux condenser, a dropping funnel and a Teflon half-moon type stirring device.
PZ, 0.280 equivalents) and 4.44 g of Reseda GP-
300 were added, and 543.6 g of MIBK was added thereto, and the temperature was increased to 70 ° C. to completely dissolve. Next, 96.88 g (0.280 equivalent) of a 50% MIBK solution of DER332 was added while stirring was continued, and the content was reduced to 30%.
The reaction was carried out at 70 ° C. for 18 hours while stirring at a speed of 0 rpm. Next, a 30% MIBK solution of isobutyric acid 40.37
g was slowly added dropwise from the funnel, and after the completion of the addition, the mixture was further reacted at the same temperature for 3 hours. 50% M of Epikote 828
44.50 g of IBK solution and MIBK 20.0 for washing
g was added secondarily, and further reacted at the same temperature for 5 hours. Finally, tolylene diisocyanate (TDJ, Coronate T-
88.81 g of a 10% MIBK solution of 100) was added dropwise from the funnel over a period of 60 minutes.
The reaction was allowed to proceed for a period of time to reach a reaction rate of almost 100%.
At the end of the reaction, a uniform and stable dispersion was obtained which was almost the same in appearance as in Example 11. The dispersion of the hardener particles thus synthesized was subjected to coagulation sedimentation and recovery of the dispersed particles with n-hexane in the same manner as in Comparative Example 8, the particles were separated by filtration through a glass filter, and further vacuum-dried at 45 ° C. for 2 days to form a cream. A colored white powder was obtained almost quantitatively. The volume average particle diameter of the obtained curing agent particles was 4.3 μm.

In this reaction, 2PZ / DER33
Spherical particles of the di-adduct are synthesized stoichiometrically, a carboxylic acid compound is added at 14% by weight to the adduct after completion of the addition reaction, and a polyfunctional epoxy compound is further added at 25% after completion of the reaction.
Then, the reaction was carried out with 10% by weight of a polyfunctional isocyanate compound.

[0122]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8] The latent curing agent for an epoxy resin of the present invention can be used in a method of reacting an excess polyfunctional epoxy compound and a polyfunctional isocyanate compound in the course of a reaction when synthesizing an amine compound / epoxy compound adduct. At any point before the addition of the isocyanate compound, the carboxylic acid compound is added to the reaction system and reacted, and the effects are shown in Tables 1 to 8.

Tables 1 and 2 show the pulverized molds synthesized by the conventional solution addition reaction (synthesis in a solvent, Examples 1 to 4) and the bulk addition reaction (synthesis without a solvent, Examples 5 and 6), respectively. Comparative examples of preparation conditions and results of hardener particles and spherical hardener particles synthesized by precipitation or dispersion addition reaction (Examples 7 to 12) in an organic solvent proposed by the present applicant, and properties as a hardener are comparative examples. Are shown together with Dicyandiamide (Dicy) and acid anhydride (MHHPA)
Are shown in Tables 3, 4 and 5 and Table 6, respectively.

As is clear from Table 1, the conventional solution addition reaction (Comparative Examples 1 and 2) and the bulk addition reaction (Comparative Example 3), followed by the solvent removal, pulverization and classification method (“pulverization method”)
Epoxy resin cured composition prepared from crushed curing agent particles of an amine compound / epoxy compound adduct that has been stoichiometrically synthesized and has not been subjected to any treatment at low temperature (80 to 100 ° C.). Although the curability is good, there is a disadvantage that the storage stability is extremely poor. Table 2
As shown in Table 2, in the case of spherical hardener particles synthesized by precipitation or dispersion addition reaction (referred to as "precipitation method") in an organic solvent (Comparative Examples 7 and 8), storage stability is slightly improved. Is not enough. Further, those obtained by excessively adding the polyfunctional epoxy compound during the course of the reaction (Comparative Examples 9 and 10) have considerably improved the potential,
Curability at low temperatures of ° C. is impaired.

The present inventors have found that when a carboxylic acid compound acts on an amine compound / epoxy compound adduct, the reactivity of the adduct at a low temperature can be significantly increased. The effect of promoting the curing reaction is considered to be due to the fact that the carboxylic acid compound forms an ionic complex with the tertiary amino group of the adduct to increase the reactivity, but also causes a decrease in the melting point of the adduct. It is considered to be. For example, the melting point of a stoichiometrically synthesized 2-phenylimidazole (2PZ) / bisphenol A diglycidyl ether (DER332) adduct of Comparative Example 2 measured by DSC (differential scanning calorimetry) is about 82 ° C. The melting point of the product (Comparative Example 4) obtained by adding 14% of 2-ethylhexanoic acid and reacting is lowered to about 55 ° C. This effect is also observed when other amine compound / epoxy compound adducts and other carboxylic acid compounds are used. Therefore, when this effect is applied to the above-mentioned system, and a carboxylic acid compound is added and further reacted (Comparative Example 6 in Table 1 and Comparative Examples 11 and 12 in Table 2), rapid curability at low temperatures is a problem. But the potential is lost because the reactivity is too high.

As described above, when the amine compound / epoxy compound adduct is reacted stoichiometrically, or when the adduct particles obtained by such a reaction are reacted with only a further polyfunctional epoxy compound, Alternatively, when the adduct is reacted under the condition of excess polyfunctional epoxy compound,
Alternatively, when further reacting two components of a polyfunctional epoxy compound and a carboxylic acid compound, hardener particles satisfying both the low-temperature curability and the potential could not be obtained. On the other hand, as shown in Examples 1 to 6 in Table 1 and Examples 7 to 12 in Table 2, in the present invention, regardless of the preparation method of the adduct particles, further multifunctional epoxy compound, By acting three components of an acid compound and a polyfunctional isocyanate compound as essential components,
The potential of the obtained curing agent particles could be greatly improved while maintaining the low-temperature curability. It was observed that the epoxy resin cured composition to which the curing agent particles prepared according to the present invention had been added had almost no increase in viscosity even after being stored at 40 ° C. for one week, and had excellent storage stability. Furthermore,
The storage stability and low-temperature quick-curing property were further improved by adjusting the addition amount of the used polyfunctional epoxy compound, carboxylic acid compound and polyfunctional isocyanate compound (Examples 2, 3, 8, 9, 10 and 12) were also possible. These curing agents can cure the epoxy resin cured composition in about 30 minutes at 80 ° C., and the original adducts (Comparative Examples 2, 7, and 8)
It showed better curing performance and potential.

Tables 1 and 2 show the cured properties of the cured products prepared from the respective cured compositions. Regarding the boiling water absorption, there is almost no difference between each of Examples and Comparative Examples, and both are at low levels. On the other hand, glass transition temperature (Tg)
As for, it can be seen that the examples of the present invention show higher Tg as compared with the comparative examples, and are excellent in heat resistance. Furthermore,
Regarding the adhesive strength, as shown in the table, the examples of the present invention showed the same or better performance as the comparative example, and exhibited a considerably high level of tensile shear adhesive strength only by heating at a low temperature of 80 ° C. for 60 minutes. We were able to.

Example 1 concerning the method of preparing the curing agent particles
As can be seen from the comparison between Examples 7 and 7 and Examples 4 and 12, spherical adduct particles obtained by the precipitation method were used as compared with the case where the crushed adduct particles obtained by the pulverization method were used. In such a case, it is possible to obtain a composition having a low viscosity of the epoxy resin cured composition, and further having excellent low-temperature rapid curability and storage stability.

Regarding the addition timing of each component, the addition timing of the polyfunctional epoxy compound may be determined in a one-step method in which an excess amount is added at the beginning of the reaction when synthesizing the amine compound / epoxy compound adduct, or during the reaction. Alternatively, any of a two-stage method in which an excess amount is added after the end of the adduct formation reaction may be used, but from a comparison between Examples 8 and 9, the two-stage method has higher reactivity at low temperatures than the one-stage method, and It can be seen that the storage stability is also excellent. The addition time of the carboxylic acid compound may be at any stage before or after the reaction of forming the adduct, or after the treatment with a further polyfunctional epoxy compound, as long as it is before the treatment with the polyfunctional isocyanate compound. Good. In the case of the pulverization type curing agent particles, when compared with the same addition amount of the same amine-based adduct, when the adduct formation reaction is completed, the pulverized and classified and then added after redispersion in a solvent (for example, Example 2) In comparison, when added immediately after the adduct formation reaction (for example, Example 4), the reactivity of the obtained curing agent is further increased. This tendency is also seen in other amine-based (Examples 5 and 6) and spherical particles (Examples 11 and 12). When the reactivity of the curing agent becomes high, it often has a bad influence on the potential, so that it is necessary to appropriately adjust the addition amount of the polyfunctional isocyanate compound as the third component.

Tables 3 and 5 and Tables 4 and 6 show comparative examples of the properties of the pulverized and spherical hardener particles obtained in the examples when used as a hardening accelerator of a high-temperature hardener. Shown in comparison with. From the table, the curing agent particles prepared in the present invention are composed of dicyandiamide (Dicy) and acid anhydride (MH).
When used as a curing accelerator for HPA), the curing temperature could be further lowered to 100 ° C. as well as 120 ° C. or higher. At 100 ° C., all showed the same or higher curing performance as the comparative example, and it was possible to cure the epoxy resin in a short time of about 15 minutes. Also,
It was found that the prepared epoxy resin composition hardly increased in viscosity even when stored at 40 ° C. for 1 hour, and that the storage stability was considerably excellent. Furthermore, it is shown that the curing accelerator obtained according to the present invention gives considerably better cured physical properties than the comparative examples.

Tables 7 and 8 show the pulverized hardener particles prepared in the present invention (Examples 1, 2, 5) and spherical hardener particles (Examples 7, 8, 9, 10, 11, 11). 12) shows the solubility in various solvents in comparison with the original adduct particles (Comparative Examples 1, 2, 3 and Comparative Examples 7, 8). As shown in the table, the amine compound / epoxy compound adduct particles have high polarity and do not dissolve in a hydrophobic solvent, but show solubility in a polar solvent such as alcohol. Further, spherical adduct particles synthesized by precipitation or dispersion addition reaction,
While it is insoluble in many general-purpose organic solvents, the crushed adduct particles obtained by solution and bulk addition reactions, followed by milling and classification differ depending on the type of amine. Shows lubricity. In the case of the former spherical particles, the polymer dispersion stabilizer used in the reaction is probably fixed on the surface of the particles to form a kind of encapsulated film,
It is thought that it works to prevent the intrusion of the solvent. In each case, the hardener particles prepared according to the present invention show a significant improvement in solvent resistance.
In particular, when a large amount of the polyfunctional isocyanate compound is added (Example 10), the compound is not dissolved in all general-purpose solvents, and it can be understood that the solvent resistance is extremely excellent. This property is considered to be extremely advantageous when used in one-part epoxy resin cured compositions for inks, paints and adhesives containing an organic solvent or a reactive diluent as a component.

(Effect of the Invention) As described above, when synthesizing the particles of the amine compound / epoxy compound adduct, (a) excess polyfunctional epoxy compound, (b) carboxylic acid compound and (c) polyfunctional The three components of the isocyanate compound are allowed to act in the above-described manner, thereby improving the solvent resistance, latency, and low-temperature fast-curing properties of the resulting adduct particles without impairing any properties. Can be.
Therefore, the adduct particles obtained by the method of the present invention are extremely useful as a latent curing agent for an epoxy resin, and by using such a curing agent, are excellent in storage stability, low-temperature rapid curing property, and cured physical properties. Epoxy resin cured composition can be prepared. Further, when the adduct particles are used in combination as a high-temperature curing type curing agent, for example, a curing accelerator for dicyandiamide or acid anhydride, an epoxy resin composition having excellent low-temperature fast-curing properties, storage stability and curing properties is obtained. It is also possible to give. The effect of the present invention is that the carboxylic acid compound acts on the amine compound / epoxy compound adduct to form an ion complex, thereby lowering the melting point of the adduct and improving its low-temperature rapid-curing property. The epoxy resin polymer portion is mixed in the adduct particles by the functional epoxy compound, or the encapsulating layer of the epoxy resin polymer is formed on the surface of the adduct particles, and furthermore, the polyfunctional isocyanate compound By forming an encapsulating layer of polyurethane or polyurethane, or by forming a mixed encapsulating layer of both, the potential and solvent resistance of the adduct particles are improved, and both effects are synergistically combined. It is considered to be achieved by

Further, such a technique is described in Japanese Patent Application No.
By applying the method for producing an amine compound / epoxy compound adduct spherical particle described in JP-B-138176,
Further, it is possible to produce a curing agent for an epoxy resin having a low production cost and excellent properties. Since the curing agent particles obtained by such a method is a spherical fine powder,
In addition to the above advantages, (1) high bulk density contributes to reduction of packaging and transportation costs; (2) good dispersibility in epoxy resin, giving a more uniform cured structure;
(3) The viscosity rise of the compound is small, and the degree of freedom of the compound design can be increased. (4) The curing agent itself is a fine powder, so that it does not deteriorate even when stored for a long time at room temperature. Therefore, it is considered that the advantages of the one-component epoxy resin cured composition can be fully utilized.

Taking advantage of this property, the latent curing agent obtained by the method of the present invention makes it possible to provide a one-component epoxy resin cured composition to a wide range of fields. Expected fields of application include structural adhesives, such as adhesives for assembling vehicles, adhesives for assembling optical machines, adhesives for assembling electronic and electrical equipment, etc .; paints, such as powder paints, baking paints, etc .; Fields, such as printed wiring board glass cloth impregnating material, IC chip sealing material, conductive paint, solder resist ink, adhesive for die bonding, printed board adhesive, conductive adhesive, etc .; Examples include coil impregnating materials, battery case adhesives, and tape head adhesives.

Continuation of front page (56) References JP-A-47-33200 (JP, A) JP-A-58-13623 (JP, A) JP-A-61-268721 (JP, A) JP-A-59-49223 (JP, A) JP-A-1-113480 (JP, A) Patent 3098760 (JP, B2) Patent 3168016 (JP, B2) Patent 2914390 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) C08G 59/50 C08G 59/40

Claims (7)

(57) [Claims] 1. An adduct is produced by reacting an amine compound with an excess amount of a polyfunctional epoxy compound with respect to the amine compound in a solvent or in a solvent to form an adduct. By obtaining an adduct particle having a predetermined particle size, redispersing the particle in a solvent and further reacting the polyfunctional isocyanate compound, an encapsulating layer formed on the surface by the polyfunctional isocyanate compound is formed. In the production of amine compound / epoxy compound adduct particles having
At an arbitrary time before the start of the reaction between the polyfunctional isocyanate compound and the adduct particles, a carboxylic acid compound is added to the reaction system and reacted with the adduct, and has a low-temperature fast-curing property and room temperature. For producing latent curing agent particles for epoxy resins having excellent storage stability, solvent resistance and cured physical properties at room temperature. 2. An amine compound and an epoxy compound are reacted with or without a solvent to form an amine compound / epoxy compound adduct, and the obtained adduct is pulverized to obtain adduct particles having a predetermined particle size. The particles are redispersed in a solvent to react with a further polyfunctional epoxy compound, and then further reacted with a polyfunctional isocyanate compound, thereby forming a polyfunctional epoxy compound on the surface thereof. In the production of an amine compound / epoxy compound adduct particle having an encapsulating layer formed thereon and an encapsulating layer formed of a polyfunctional isocyanate compound thereon, or a mixed encapsulating layer of the two, a polyfunctional isocyanate compound is added. Characterized in that a carboxylic acid compound is added to the reaction system and reacted with the adduct at any time before the start of the reaction with the body particles, A method for producing latent curing agent particles for epoxy resins, which has curability and is excellent in storage stability at room temperature, solvent resistance and cured physical properties. 3. An amine compound and an excess amount of a polyfunctional epoxy compound with respect to the amine compound are dissolved together with the amine compound and the epoxy compound in the presence of a dispersion stabilizer. After reacting in an organic solvent that does not dissolve, by adding a polyfunctional isocyanate compound and further reacting, having an encapsulating layer formed by a polyfunctional epoxy resin on its surface, Further, in the production of spherical particles of an amine compound / epoxy compound adduct having an encapsulating layer formed of a polyfunctional isocyanate compound on the epoxy encapsulating layer or a mixed encapsulating layer of both, the addition of a polyfunctional isocyanate compound At any time before, the carboxylic acid compound is added to the reaction system and reacted, having a low-temperature rapid-curing property and at room temperature. A method for producing a latent curing agent spherical particle for an epoxy resin having excellent storage stability, solvent resistance and cured physical properties. 4. An amine compound and an epoxy compound are reacted in the presence of a dispersion stabilizer in an organic solvent in which both the amine compound and the epoxy compound are dissolved but an adduct formed from both is insoluble. During or after the completion of the reaction, a further polyfunctional epoxy compound is added to cause a further reaction, and then a further polyfunctional isocyanate compound is added to cause a further reaction. Addition of an amine compound / epoxy compound having an encapsulation layer formed of a functional epoxy resin and further having an encapsulation layer formed of a polyfunctional isocyanate compound on the epoxy encapsulation layer or a mixed encapsulation layer of both. In the production of spherical particles, at any time before the addition of the polyfunctional isocyanate compound, the carboxylic acid compound may be added to the reaction system and reacted. A method for producing a latent curing agent spherical particle for an epoxy resin, which has a low-temperature fast-curing property, and has excellent storage stability at room temperature, solvent resistance and cured physical properties. 5. Latent curing agent particles for an epoxy resin produced by the method according to claim 1. 6. A one-component thermosetting composition comprising the latent curing agent particles for epoxy resin according to claim 5 and an epoxy resin as main components. 7. A one-pack type thermosetting composition comprising an epoxy resin and a high-temperature curing type curing agent as main constituents, and the latent curing agent particles for epoxy resin according to claim 5 added as a curing accelerator. .