KR101243511B1 - Microcapsule-type latent curing agent for epoxy resin and process for production thereof, and one-pack-type epoxy resin composition and cured product thereof - Google Patents

Abstract

The present invention relates to a microcapsule type latent curing agent having a core and a capsule covering the same. In the microcapsule type curing agent according to the invention, the core comprises an amine adduct and the capsule comprises the reaction product of an isocyanate with a compound having active hydrogen groups and / or water. At least some of the reaction products are bound to the core by reaction with an amine adduct.

Description

MICROCAPSULE-TYPE LATENT CURING AGENT FOR EPOXY RESIN AND PROCESS FOR PRODUCTION THEREOF, AND ONE-PACK-TYPE EPOXY RESIN COMPOSITION AND CURED PRODUCT THEREOF}

The present invention relates to a microcapsule-type latent curing agent for epoxy resins and a method for producing the same, and a one-component epoxy resin composition and an epoxy resin cured product.

Epoxy resins are used in a wide range of applications, such as paints, electrical and electronic insulating materials, adhesives, and the like because their cured products have excellent performance in terms of mechanical properties, electrical properties, thermal properties, chemical resistance, adhesiveness, and the like. Most of the epoxy resin compositions which are generally used at present are so-called two-liquid substances in which the two liquids of the epoxy resin and the curing agent are mixed at the time of use.

While the two-component epoxy resin composition can be cured at room temperature, storage and handling are complicated because it is necessary to store the epoxy resin and the curing agent separately and use them after weighing and mixing both as necessary. In addition, since the pot life is limited, it is not possible to mix in large quantities in advance, so that the mixing frequency increases, so that the efficiency decrease cannot be avoided.

In order to solve the problem of such a two-component epoxy resin composition, several one-component epoxy resin compositions have been proposed so far. For example, dicyandiamide, BF ₃ - there is an amine complex, amine salts and modified imidazole compounds, such as the latent curing agent already incorporated in the epoxy resin.

Moreover, the study which reacts the surface of a powdery amine compound with an isocyanate, inactivates the surface of an amine compound, and gives potential to a hardening | curing agent is performed (patent documents 1-5). Moreover, the microcapsule type hardening | curing agent encapsulated by making a powdery amine compound react with an isocyanate in an epoxy resin is proposed (patent documents 6-8). For example, Patent Document 6 discloses a master batch type curing agent obtained by a method of dispersing an amine curing agent as a core in an epoxy resin and adding an isocyanate and water thereto to form a shell. Other methods include a method of mixing an epoxy resin and an amine curing agent, immediately freezing to stop the progress of the reaction, microencapsulating the amine curing agent, and adsorbing the curing agent to the molecular sieve.

Japanese Patent Publication (Small) 58-55970 Japanese Patent Laid-Open No. 59-27914 Japanese Patent Publication No. 59-59720 European Patent Application Publication No. 193068 Japanese Patent Laid-Open No. 61-190521 Japanese Patent Laid-Open No. 1-70523 Japanese Patent Laid-Open No. 2004-269721 Japanese Patent Laid-Open No. 2005-344046

However, in the case of conventional latent curing agents, those having excellent storage stability have low curing properties and require high temperature or a long time for curing. On the other hand, high hardenability is low in storage stability, and needs to be stored at low temperature, for example, -20 degreeC. For example, the one-component epoxy resin composition blended with dicyandiamide has a storage stability of 6 months or more in the case of normal temperature storage, but requires a curing temperature of 170 ° C or higher. When using a hardening accelerator together in order to reduce this hardening temperature, hardening at 130 degreeC-150 degreeC is possible, for example. In this case, however, storage stability at room temperature is insufficient, and storage at low temperature is inevitable, and the pot life (photo life) is shortened. As a result, the potential of dicyandiamide is not fully utilized. The epoxy resin composition used when producing a film-shaped molded article or a product impregnated with an epoxy resin composition is often used as a compound containing a solvent, a reactive diluent, and the like. The use of a curing agent leads to extremely low storage stability. Therefore, it is necessary to make a compounded product substantially two-component, and the improvement was calculated | required.

As in Patent Literature 3, the method of blocking the surface functional group of the amine compound is not necessarily sufficient in view of the properties required as the one-component epoxy resin composition, particularly in terms of storage stability. Moreover, the uniformity is also important in actually using a one-component epoxy resin composition. Therefore, generally, it is necessary to disperse | distribute powdery hardening | curing agent uniformly in an epoxy resin with a roll or other apparatus. By the way, any of the methods disclosed in Patent Literatures 1 to 4 are used to destroy the inert surface layer once formed by the mechanical shearing force accompanying the dispersion operation at room temperature, resulting in sufficient storage stability to withstand practical use. There is also the problem of not losing.

On the other hand, according to the above-mentioned method of freezing, microencapsulation, or molecular sieve, relatively good storage stability is obtained, but the reality is that practical use is hardly achieved because of insufficient performance, especially hardened product characteristics.

As described above, there is a strong demand for a one-component epoxy resin composition capable of achieving both high curability and excellent storage stability. In particular, in recent years, the improvement of the hardening characteristic and storage stability is calculated | required further with respect to the one-component resin composition for the productivity improvement in an electronic material use.

Therefore, an object of this invention is to provide the hardening | curing agent which enables both the low temperature curability of the one-component epoxy resin composition, and the outstanding storage stability, and its manufacturing method. Moreover, an object of this invention is to provide the one-component epoxy resin composition and its hardened | cured material which used such a hardening | curing agent.

In one aspect, the invention relates to a microcapsule type latent curing agent having a core and a capsule covering the same. In the microcapsule type curing agent according to the invention, the core comprises an amine adduct and the capsule comprises the reaction product of an isocyanate with a compound having active hydrogen groups and / or water. At least some of the reaction products are bound to the core by reaction with an amine adduct. The microcapsule type curing agent according to the present invention is used to cure an epoxy resin. The microcapsule type latent curing agent according to the present invention may be in powder form.

According to the microcapsule type curing agent according to the present invention, both low-temperature curability and excellent storage stability of the one-component epoxy resin composition is possible.

In order to make the effect by this invention further remarkable, it is preferable that the said core contains 50 to 100% of amine adduct by mass ratio.

It is preferable that the ratio of a capsule is 5-80 mass% based on the total mass of this microcapsule type latent hardener. Thereby, it becomes possible to make both low temperature hardenability and storage stability compatible with a higher level.

The ratio of the capsule may be 40 to 80 mass%. Accordingly, the latent curing agent may have very good storage stability and solvent resistance. In addition, better low temperature curability is also achieved. Therefore, even when the latent curing agent is mixed with a solvent and left for a long time, the core component of the microcapsule-type latent curing agent does not elute with the solvent, and thus the low-temperature curing property can be maintained.

The proportion of the capsules may be 15 to 40 mass%. Accordingly, the latent curing agent may have better storage stability and solvent resistance, and may also have better low temperature curing properties, and may combine these characteristics at a very high level. Therefore, even when, for example, the latent curing agent is mixed with the epoxy resin and left for one week in a heated state such as about 40 ° C., the reaction with the epoxy resin proceeds, the viscosity rises, and the low temperature curing characteristics are lost. There is no case, and good storage stability and good low temperature hardenability can be expressed.

The proportion of the capsules may be 5 to 15 mass%. Thereby, the latent curing agent may have better storage stability and solvent resistance while having very good low temperature curing properties.

In another aspect, the present invention relates to a method for producing a microcapsule type latent curing agent for epoxy resins. The production method according to the present invention includes a step of forming a capsule covering the core by reacting an amine adduct contained in the core with a compound having an active hydrogen group and an isocyanate and / or water in a dispersion medium. The manufacturing method which concerns on this invention may further be equipped with the process of taking out the powdery microcapsule type latent hardener which has a core and a capsule from the mixture after reaction.

According to the production method according to the present invention, it is possible to obtain a microcapsule type curing agent that enables both low-temperature curability and excellent storage stability of the one-component epoxy resin composition while suppressing variations in properties. The microcapsule-type latent curing agent according to the present invention may be one obtained by the manufacturing method according to the present invention.

In another aspect, the present invention relates to a one-component epoxy resin composition. The one-component epoxy resin composition according to the present invention contains the microcapsule-type latent curing agent for epoxy resin and the epoxy resin according to the present invention.

The one-component epoxy resin composition according to the present invention has low temperature curability and excellent storage stability.

The microcapsule-type latent curing agent for epoxy resins may be heat treated in an epoxy resin. The one-component epoxy resin composition according to the present invention preferably contains 5 to 70 parts by mass of the microcapsule type latent curing agent with respect to 100 parts by mass of the total amount of the epoxy resin and the microcapsule type latent curing agent.

In another aspect, the present invention relates to a cured product of the epoxy resin composition. The cured product according to the present invention is formed by curing the one-component epoxy resin composition according to the present invention by heating. The cured product according to the present invention is particularly excellent in terms of electrical properties (insulation).

According to the microcapsule type curing agent according to the present invention, both low-temperature curability and excellent storage stability of the one-component epoxy resin composition are possible. For this reason, the microcapsule type hardening | curing agent which concerns on this invention is used suitably in order to improve productivity in electronic material use etc.

The powdery microcapsule-type latent curing agent according to the present invention also has excellent effect in the following aspects.

(1) Since it is powdery, it can disperse | distribute easily and uniformly to the epoxy resin according to the objective in consideration of hardening characteristics, the physical property of hardened | cured material, etc. Moreover, the degree of freedom of the compounding ratio of the hardening | curing agent in an epoxy resin composition is also high.

(2) Since the capsule portion can be easily controlled, a latent curing agent having good curing properties and good storage stability can be easily achieved in accordance with the purpose.

(3) Since the one-component epoxy resin composition can be easily produced, workability at the time of use is improved, and high reliability of the product is obtained.

The microcapsule-type latent curing agent according to the present invention also has an effect that the change in performance is small by the mechanical shear force applied when producing the one-component epoxy resin composition.

According to the production method according to the present invention, a microcapsule type curing agent which enables both low-temperature curability and excellent storage stability of a one-component epoxy resin composition can be obtained while suppressing fluctuations in characteristics. In the conventional manufacturing method of reacting a powdered amine compound with an isocyanate in an epoxy resin, a large amount of powdered amine compound is added to the epoxy resin in order to increase the amount of the microcapsule-type latent curing agent, for example, for the purpose of improving low temperature curing properties. Needs to be. When the amount of the powdered amine compound increases, the viscosity increases, making it difficult to perform a uniform encapsulation reaction. As a result, the variation of the properties between lots becomes large, the defective rate of a product becomes high, or the degree of capsule formation is insufficient, and sufficient storage stability is not obtained. Moreover, when using the component highly reactive with an epoxy resin as a core material in order to improve hardening characteristic, there exists also a problem that hardening reaction advances in an epoxy resin, and the latent hardening | curing agent which has sufficient characteristic cannot be synthesized. According to the production method according to the present invention, since the reaction between the core and the epoxy resin which causes the viscosity increase and the reaction between the isocyanate, water and the epoxy resin can be suppressed, a high-liquid one-component epoxy resin can be obtained. . In these respects, the production method according to the present invention has an advantageous effect compared with the conventional method.

According to the method for producing a microcapsule-type latent curing agent according to the present invention, compared to the method of forming a shell after blending a powdered amine compound as a curing agent in an epoxy resin, since the curing reaction and viscosity increase are small, it is more easily and uniformly. The reaction can proceed. As a result, the characteristic variation between lots becomes small. It is also easy to remove byproducts. Furthermore, since it is not necessary to make a hardening | curing agent different for every kind of epoxy resin to combine, work efficiency is favorable and the range of selection of an epoxy resin is also wide.

Although the viscosity of the conventional master batch type hardener is high, it was difficult for the epoxy resin composition to achieve sufficient fluidity, but according to the present invention, it is possible to obtain a one-component epoxy resin composition having sufficiently high fluidity. In recent years, especially in the field of electronic devices, in order to cope with higher density of circuits and improved connection reliability, the one-component epoxy resin composition used as one of the connection materials has a high fluidity because filling into a narrow gap is more important. It is.

In the case of forming a shell on the surface of the powdered amine curing agent by adding isocyanate and water in the epoxy resin, a side reaction in which the primary amine produced by the reaction of the isocyanate with water is likely to react with the epoxy resin as a side reaction. The reproducibility of the product is difficult to be obtained. Moreover, since a hardening | curing agent is obtained in the state of the compound (master batch) with a specific epoxy resin, there also existed a problem that the degree of freedom of compounding was limited. The present invention is also advantageous in solving these problems.

Taking advantage of the above effects, the microcapsule-type latent curing agent and the one-component epoxy resin composition according to the present invention can be used in a wide range of applications. For example, as an adhesive, headlights, gasoline tanks in automobiles, hemming flanges in bonnets, etc., joining of steel plates in bode and roof sections, speaker magnets in electrical fields, impregnation and adhesion of motor coils, tape Use of die bonding adhesive, IC chip sealant, chip coating material, chip mount material, printing substrate adhesive, film adhesive, anisotropic conductive film, anisotropic conductive paste, etc. As the one-component epoxy resin composition according to the present invention can be used. As another use, powder coating material, soldering resist ink, electroconductive paint, etc. are mentioned in the coating field. Moreover, this invention can also be used for an electrical insulation material, laminated structure, etc. In particular, in recent years, further improvement of the curing properties and storage stability has been required for the one-component resin composition in order to improve productivity in electronic material applications.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, this invention is not limited to the following embodiment.

The microcapsule-type latent curing agent according to the present embodiment has a particulate core and a capsule covering the same. The capsule is a film covering at least a portion of the core surface.

The core contains the amine adduct as the main component. More specifically, the core usually contains 50 to 100%, preferably 60 to 100%, of amine adducts by mass ratio. When the mass ratio of the amine adduct is less than 50%, it is relatively difficult to achieve both curing characteristics and storage stability.

An amine adduct is a compound which has an amino group obtained by reaction of an epoxy resin and an amine compound.

As the epoxy resin used for obtaining the amine adduct, any one or a mixture of a mono epoxy compound and a polyvalent epoxy compound can be used. As a monoepoxy compound, for example, butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-tert- butylphenyl glycidyl ether, ethylene oxide, propylene oxide, for example And paraxylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexate and glycidyl benzoate. Examples of the polyvalent epoxy compound include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrabromobisphenol A and tetrachlorobisphenol A, tetrafluoro Bisphenol-type epoxy resins obtained by glycidylating bisphenols such as lobbyisphenol A; Epoxy resins obtained by glycidylating other divalent phenols such as biphenols, dihydroxynaphthalene and 9,9-bis (4-hydroxyphenyl) fluorene; 1,1,1-tris (4-hydroxyphenyl) methane, 4,4- (1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl) ethylidene) bisphenol Epoxy resins obtained by glycidylating trisphenols; Epoxy resins obtained by glycidylating tetrakisphenols such as 1,1,2,2, -tetrakis (4-hydroxyphenyl) ethane; Novolak-type epoxy resin obtained by glycidylating novolaks, such as a phenol novolak, a cresol novolak, a bisphenol A novolak, a brominated phenol novolak, and a bisphenol A novolak; Epoxy resins obtained by glycidylating polyhydric phenols, aliphatic ether type epoxy resins obtained by glycidylating polyhydric alcohols such as glycerin and polyethylene glycol; ether ester epoxy resins obtained by glycidylating hydroxycarboxylic acids such as p-oxybenzoic acid and β-oxynaphthoic acid; Ester type epoxy resin obtained by glycidylating polycarboxylic acid, such as phthalic acid and terephthalic acid; Glycidyl epoxy resins such as glycidylated compounds of amine compounds such as 4,4-diaminodiphenylmethane and m-aminophenol and amine epoxy resins such as triglycidyl isocyanurate, and 3,4- Alicyclic epoxides, such as epoxycyclohexylmethyl-3 ', 4'- epoxycyclohexane carboxylate, are illustrated.

As an epoxy resin, since the storage stability of an epoxy resin composition can be improved, a polyhydric epoxy compound is preferable. The polyvalent epoxy compound is preferably a glycidyl epoxy resin because of the overwhelming productivity of the amine compound. Since the adhesiveness and heat resistance of hardened | cured material are excellent, it is more preferable that a polyhydric epoxy compound is glycidylated polyhydric phenols, and its bisphenol type epoxy resin is still more preferable. In particular, the bisphenol A type epoxy resin which is an epoxy resin which glycidylated bisphenol A, and the bisphenol F type epoxy resin which is an epoxy resin which glycidylated bisphenol F are preferable, and bisphenol A type epoxy resin is the most preferable among these. These epoxy resins may be used alone or in combination.

The amine compound used to obtain the amine adduct is preferably selected from compounds having a primary amino group and / or secondary amino group and no tertiary amino group, and compounds having a tertiary amino group and an active hydrogen group. As a compound which has a primary amino group and / or a secondary amino group, and does not have a tertiary amino group, For example, methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, First amines such as triethylenetetramine, ethanolamine, propanolamine, cyclohexylamine, isophoronediamine, aniline, toluidine, diaminodiphenylmethane and diaminodiphenylsulfone, and dimethylamine, diethylamine, dipropyl Amine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine, dicyclohexylamine, piperidine, piperidone, diphenylamine, phenylmethylamine and phenylethylamine The same 2nd amine is mentioned.

In the compound having a tertiary amino group and an active hydrogen group, examples of the active hydrogen group include primary amino groups, secondary amino groups, hydroxyl groups, thiol groups, carboxylic acids and hydrazide groups. Examples of the compound having a tertiary amino group and an active hydrogen group include 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol, 1 Aminoalcohols such as butoxymethyl-2-dimethylaminoethanol, methyldiethanolamine, triethanolamine and N-β-hydroxyethyl morpholine; Aminophenols such as 2- (dimethylaminomethyl) phenol and 2,4,6-tris (dimethylaminomethyl) phenol; 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-aminoethyl-2-methyl Midazole, 1- (2-hydroxy-3-phenoxypropyl) -2-methylimidazole, 1- (2-hydroxy-3-phenoxypropyl) -2-ethyl-4-methylimidazole Such as 1- (2-hydroxy-3-butoxypropyl) -2-methylimidazole and 1- (2-hydroxy-3-butoxypropyl) -2-ethyl-4-methylimidazole Imidazoles; 1- (2-hydroxy-3-phenoxypropyl) -2-phenylimidazoline, 1- (2-hydroxy-3-butoxypropyl) -2-methylimidazoline, 2-methylimidazoline , 2,4-dimethylimidazoline, 2-ethylimidazoline, 2-ethyl-4-methylimidazoline, 2-benzylimidazoline, 2-phenylimidazoline, 2- (o-tolyl)- Imidazoline, tetramethylene-bis-imidazoline, 1,1,3-trimethyl-1,4-tetramethylene-bis-imidazoline, 1,3,3-trimethyl-1,4-tetramethylene-bis Imidazoline, 1,1,3-trimethyl-1,4-tetramethylene-bis-4-methylimidazoline, 1,2-phenylene-bis-imidazoline, 1,3-phenylene-bis Imidazolines such as -imidazoline, 1,4-phenylene-bis-imidazoline, 1,4-phenylene-bis-4-methylimidazoline; Dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, dipropylaminoethylamine, dibutylaminoethylamine, N-methylpipepe Tertiary aminoamines such as razin, N-aminoethylpiperazine and diethylaminoethylpiperazine; Aminomercaptans such as 2-dimethylaminoethanethiol, 2-mercaptobenzoimidazole, 2-mercaptobenzothiazole, 2-mercaptopyridine and 4-mercaptopyridine; Aminocarboxylic acids such as N, N-dimethylaminobenzoic acid, N, N-dimethylglycine, nicotinic acid, isnicotinic acid and picolinic acid; And amino hydrazides such as N, N-dimethylglycine hydrazide, nicotinic acid hydrazide and isnicotinic acid hydrazide.

As the amine compound, a compound having a tertiary amino group and an active hydrogen group is preferable because of excellent balance between storage stability and curability. Especially, imidazoles are more preferable, and 2-methylimidazole and 2-ethyl-4-methylimidazole are further more preferable.

The core may contain one or two or more other components in addition to the amine adduct. By adding other components, desired characteristics can be imparted. For example, the core may contain a compound having a higher reactivity with an epoxy resin or a curing accelerator than the amine adduct in order to enable curing at a lower temperature or in a shorter time. The additive necessary for hardened | cured material can also be previously added to a core.

It is preferable that the other component is solid at normal temperature (25 degreeC). Preferably it is a solid phase at 40 degreeC, More preferably, it is a solid phase at 60 degreeC. If a component that is liquid at room temperature is used, encapsulation becomes difficult or the storage stability of the one-component epoxy resin composition tends to be lowered.

It is preferable that the amine adduct and the other components are uniformly mixed in the core. As a method of realizing uniform mixing, by heating and melting the amine adduct and the other components together, and after sufficiently mixing, cooling to pulverization to room temperature, or pulverizing one of them, by dispersing the other and uniformly dispersing the other There is a method of forming water, cooling to room temperature and grinding.

It is preferable that a core is particulate form which has an average particle diameter of 0.1-50 micrometers. The average particle diameter of the core is more preferably 0.5 to 10 m, still more preferably 0.5 to 5 m. If the average particle diameter of the core is less than 0.1 µm, both the curing properties and the storage stability tend to be relatively difficult. Moreover, if an average particle diameter of a core is 50 micrometers or less, it will become easy to obtain a homogeneous hardened | cured material. The average particle diameter refers to the median diameter. The average particle diameter of the core can be measured by a laser diffraction particle size distribution measuring device.

The shape of the core is not particularly limited and may be either spherical or indefinite. However, spherical shape is preferable for reducing the viscosity of the one-component epoxy resin composition. Here, the term spherical includes not only a spherical shape but also a shape in which an indefinite angle has a rounded shape.

The microcapsule-type latent curing agent is formed by reacting, for example, an amine adduct contained in the core with a compound having an active hydrogen group and an isocyanate and / or water in a dispersion medium to form a capsule covering the core, and from the mixture after the reaction. It can obtain by the manufacturing method provided with the process of taking out the microcapsule type hardening | curing agent which has a core and a capsule.

Isocyanates are compounds having at least one isocyanate group, preferably at least two isocyanate groups. Preferred isocyanates include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, low molecular triisocyanates and polyisocyanates. Examples of the aliphatic diisocyanate include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate and trimethylhexamethylene diisocyanate. Examples of the alicyclic diisocyanate include isophorone diisocyanate, 4-4'-dicyclohexyl methane diisocyanate, norbornane diisocyanate, 1,4-isocyanate cyclohexane, 1,3-bis (isocyanate methyl) -cyclohexane and And 1,3-bis (2-isocyanatepropyl-2yl) -cyclohexane. Examples of the aromatic diisocyanate include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate and 1,5-naphthalene diisocyanate. As an example of low molecular triisocyanate, 1,6,11- undecane triisocyanate, 1,8- diisocyanate-4-isocyanate methyl octane, 1,3,6-hexamethylene triisocyanate, 2,6- diisocyanate hexanoic acid- Alicyclic triisocyanate compounds, such as aliphatic triisocyanate compound of 2-isocyanate ethyl, 2, 6- diisocyanate hexanoate 1-methyl-2-isocyanate ethyl, tricyclohexyl methane triisocyanate, and bicycloheptane triisocyanate, and triphenyl Aromatic triisocyanate compounds, such as methane triisocyanate and a tris (isocyanate phenyl) thiophosphate, are mentioned. Examples of the polyisocyanate include polymethylene polyphenylpolyisocyanate, polyisocyanate derived from the diisocyanate and low molecular triisocyanate. Examples of the polyisocyanate derived from the diisocyanate and the triisocyanate include isocyanurate polyisocyanate, biuret polyisocyanate, urethane polyisocyanate, allophanate polyisocyanate and carbodiimide polyisocyanate. These isocyanates can be used individually or in combination of 2 or more types.

The reaction between the active hydrogen group and the isocyanate of the amine adduct causes the amine adduct and the isocyanate to bond to form a film by the product on the surface of the core. Then, the presence of a compound having an active hydrogen group and / or water in the reaction system causes the film containing the reaction product of these and isocyanate to grow to form a capsule. At least some of the reaction products contained in the capsule are bound to the core by urethane bonds produced by the reaction of the isocyanate with the amine adduct. It is thought that sufficient storage stability of the one-component epoxy resin composition is obtained by using the microcapsule-type latent curing agent in which the film has grown in this way.

In the microcapsule latent curing agent, the ratio of the capsule (inert film) is preferably 5 to 80% by mass based on the total mass of the microcapsule latent curing agent. The ratio of the capsule may be 40 to 80 mass%, 15 to 40 mass%, or 5 to 15 mass%, depending on the desired use or purpose.

The ratio of the capsule is, for example, by dispersing a microcapsule-type latent curing agent of mass M1 in a solvent that selectively dissolves a portion of the core, measuring the mass M2 of the solid content of the undissolved solution at that time, and the following formula: It can obtain | require by the method of calculating the ratio of a capsule from ratio (mass%) = (M2 / M1) * 100. As a solvent for selectively dissolving the core, for example, methanol is used.

As an active hydrogen group of the compound used for forming a capsule, a primary amino group, a secondary amino group, a hydroxyl group, a thiol group, a carboxylic acid, and a hydrazide group are illustrated. The compound having one or more active hydrogen groups in one molecule may be used. Preferably, the compound having two or more active hydrogen groups in one molecule is used. By using a compound having two or more active hydrogen groups, the coating on the surface of the core can be efficiently grown to produce a microcapsule-type latent curing agent having particularly excellent storage stability. The compound which has an active hydrogen group can be used individually by 1 type or in combination of 2 or more type.

Reaction of capsule formation can be performed in the reaction liquid which disperse | distributed the core in a dispersion medium. It is preferable to perform reaction at the temperature below melting | fusing point or softening point of the component (especially amine adduct) which comprises a core.

The boiling point of the dispersion medium is preferably 150 ° C. or lower at 1 atmosphere. If the boiling point of a dispersion medium is 150 degreeC or more, it will become difficult to remove a dispersion medium from a reaction liquid. In addition, the viscosity of the dispersion medium is preferably 1000 mPa · s or less at 25 ° C. If the viscosity of a dispersion medium is 1000 mPa * s or more, uniform reaction will become difficult, and the microcapsule type latent hardening | curing agent obtained may aggregate and may fall remarkably deteriorate hardening characteristic. From the same viewpoint, More preferably, the boiling point of a dispersion medium is 50-120 degreeC, and the viscosity of a dispersion medium is 0.2-10 mPa * s.

It is preferable that a dispersion medium does not have substituents, such as an active hydrogen group and an epoxy group which reacts with an amine adduct. These substituents may possibly inhibit the reaction of capsule formation. As a specific example of a preferable dispersion medium, cyclohexane (boiling point 80.7 degreeC, viscosity 0.898 mPa * s: 25 degreeC) and hexane (boiling point 69 degreeC, viscosity 0.299 mPa * s: 25 degreeC) are mentioned.

After the capsule is formed, the dispersion medium is removed from the mixture including the microcapsular latent curing agent, the dispersion medium and the like. In the dispersion medium, an unreacted isocyanate or by-product, water and / or a compound having an active hydrogen group may remain, but the microcapsule-type latent curing agent can be taken out from the residue in the dispersion medium by removing the dispersion medium. If unreacted material is contained in the microcapsule latent curing agent, there is a possibility that the storage stability is lowered.

Although the method of removing a dispersion medium is not specifically limited, It is preferable to remove the remainder, such as an unreacted isocyanate or a by-product, water, and a compound which has an active hydrogen group with a dispersion medium. Filtration is mentioned as a preferable method. After removing a dispersion medium by filtration etc., it is preferable to wash | clean a microcapsule type latent hardening | curing agent. Although the method of washing | cleaning is not specifically limited, After filtration, it can wash | clean using the solvent which does not melt | dissolve a microcapsule type latent hardener. As such a solvent, ones similar to the dispersion medium may be used. By washing, unreacted compounds attached to the surface of the microcapsule type latent curing agent can be removed. The filtered microcapsule latent curing agent becomes powdery by drying. Although the method of drying is not specifically limited, It is preferable to dry at the temperature below melting | fusing point or softening point of a core. Pressure drying may be mentioned as such a method. The powdery microcapsule type curing agent can be easily applied for a wide variety of formulations in the one-component epoxy resin composition.

In the case of the method of encapsulating in an epoxy resin, the storage stability decreases as a result of unreacted isocyanate or by-product, water and / or a compound having an active hydrogen group remaining in the one-component epoxy resin composition. In addition, when powdered amine adduct particles are added to the epoxy resin at a high concentration, the viscosity becomes remarkably high, so that a uniform reaction cannot be performed, the difference in properties between the lots becomes large, and the encapsulation reaction itself is impossible. There is also a problem. In order to enhance the reactivity, encapsulation is performed using a core containing a compound having a high reactivity with an epoxy resin or a highly reactive epoxy resin as a dispersion medium. Production of a curing agent or one-component epoxy resin composition becomes difficult.

The reaction of capsule formation may be performed two or more times as necessary. In this case, at least one reaction may be performed between the amine adduct, the isocyanate and the compound having an active hydrogen group and / or water, and in addition to this, any one selected from the compound having an isocyanate and an active hydrogen group and / or water is used. The reaction can also be carried out. 5 times or less of reaction of capsule formation is preferable at the point which suppresses manufacturing cost, More preferably, it is 3 times or less.

The one-component epoxy resin composition according to the present embodiment contains a microcapsule latent curing agent and an epoxy resin. Although the quantity of a microcapsule type latent hardener is not specifically limited, Usually, it is about 5-70 mass parts with respect to 100 mass parts of total amounts of an epoxy resin and a microcapsule type latent hardener. If this amount is less than 5 parts by mass, the epoxy resin tends to be hard to be cured sufficiently or a long time is required for curing. If it exceeds 70 parts by mass, the fluidity of the epoxy resin composition tends to be lowered.

As an epoxy resin used for the one-component epoxy resin composition, an epoxy compound having an average of two or more epoxy groups can be preferably used. Specifically, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrabromobisphenol A, tetrachlorobisphenol A and tetrafluorobisphenol Bisphenol-type epoxy resin obtained by glycidylating bisphenols, such as A; Epoxy resins obtained by glycidylating other divalent phenols such as biphenols, dihydroxynaphthalene and 9,9-bis (4-hydroxyphenyl) fluorene; 1,1,1-tris (4-hydroxyphenyl) methane and 4,4- (1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl) ethylidene) bisphenol Epoxy resins obtained by glycidylating trisphenols; Epoxy resins obtained by glycidylating tetrakisphenols such as 1,1,2,2, -tetrakis (4-hydroxyphenyl) ethane; Novolak-type epoxy resins obtained by glycidylating novolaks such as phenol novolak, cresol novolak, bisphenol A novolak, brominated phenol novolak, and brominated bisphenol A novolak; Epoxy resins obtained by glycidylating polyhydric phenols, aliphatic ether type epoxy resins obtained by glycidylating polyhydric alcohols such as glycerin and polyethylene glycol; ether ester epoxy resins obtained by glycidylating hydroxycarboxylic acids such as p-oxybenzoic acid and β-oxynaphthoic acid; Ester type epoxy resin obtained by glycidylating polycarboxylic acid, such as phthalic acid and terephthalic acid; Glycidyl epoxy resins such as glycidylated compounds of amine compounds such as 4,4-diaminodiphenylmethane and m-aminophenol and amine epoxy resins such as triglycidyl isocyanurate, and 3,4- Alicyclic epoxides, such as an epoxy cyclohexyl methyl-3 ', 4'- epoxycyclohexane carboxylate, etc. are illustrated. Other examples of the epoxy resins include modified epoxy resins such as urethane-modified epoxy resins, rubber-modified epoxy resins, and alkyd-modified epoxy resins. These epoxy resins may be used independently or may be used together 2 or more types.

The one-component epoxy resin composition may further contain at least one curing agent selected from the group consisting of acid anhydrides, phenols, hydrazides, and guanidines, in addition to the microcapsule-type latent curing agent. Moreover, the one-component epoxy resin composition may contain extenders, reinforcing materials, fillers, conductive fine particles, pigments, organic solvents, reactive diluents, non-reactive diluents, resins, crystalline alcohols, coupling agents, and the like, as desired.

Examples of the filler include coal tar, glass fiber, asbestos fiber, boron fiber, carbon fiber, cellulose, polyethylene powder, polypropylene powder, quartz powder, mineral silicate, mica, asbestos powder, slate powder, kaolin, aluminum oxide trihydrate , Aluminum hydroxide, chalk powder, gypsum, calcium carbonate, antimony trioxide, fenton, silica, aerosol, lithopone, barite, titanium dioxide, carbon black, graphite, carbon nanotube, fullerene, iron oxide, gold, silver, aluminum powder, Iron, nano-sized metal crystals, intermetallic compounds, and the like. These are all used effectively according to the use.

Examples of the conductive fine particles include, for example, solder particles, nickel particles, nano-sized metal crystals, particles coated with metals on the surface of metals, inclined particles of copper and silver, for example styrene resins, urethane resins, The particle | grains which coat | covered resin particle | grains, such as a melamine resin, an epoxy resin, an acrylic resin, a phenol resin, and a styrene butadiene resin, with conductive thin films, such as gold, nickel, silver, copper, and solder, etc. are mentioned.

As an organic solvent, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and butyl acetate are mentioned, for example.

Examples of the reactive diluent include butylglycidyl ether, N, N'-glycidyl-o-toluidine, phenylglycidyl ether, styrene oxide, ethylene glycol diglycidyl ether, and propylene glycol diglycidyl. Ether and 1,6-hexanediol diglycidyl ether. Examples of the non-reactive diluent include dioctyl phthalate, dibutyl phthalate, dioctyl adate and a petroleum solvent.

As resin, a polyester resin, a polyurethane resin, an acrylic resin, a polyether resin, a melamine resin, and a phenoxy resin are mentioned, for example.

Examples of the crystalline alcohol include 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, pentaerythritol, sorbitol, sucrose and trimethylolpropane.

The one-component epoxy resin composition preferably includes a step of dispersing the microcapsule-type latent curing agent in a mixture mixed with the microcapsule-type latent curing agent and an epoxy resin, and a step of heat treating the dispersed microcapsule-type latent curing agent. It can obtain by the manufacturing method.

The microcapsule-type latent curing agent can be dispersed in the epoxy resin by stirring the mixture of the microcapsule-type latent curing agent and the epoxy resin using a mixer or a roll.

The storage stability is further improved because the epoxy resin is blown into the capsule by heat-treating the microcapsule-type latent curing agent in the epoxy resin. The temperature of heat processing is higher than normal temperature (25 degreeC), and below melting | fusing point or softening point of the amine adduct which comprises a core is preferable. The storage stability improvement effect tends to become small at temperature lower than normal temperature, and the characteristic of a hardening | curing agent tends to fall by reaction with an epoxy resin at temperature higher than melting | fusing point or softening point of an amine adduct. The treatment time is preferably 5 minutes to 72 hours in terms of productivity.

The one-component epoxy resin composition according to the present embodiment is cured by heating to form a cured product. Such one-component epoxy resin compositions are useful as conductive materials, anisotropic conductive materials, insulating materials, sealants, coating materials, coating compositions, prepregs, thermal conductive materials, and the like, in addition to adhesives and / or bonding pastes and bonding films.

[Example]

Hereinafter, an Example is given and this invention is demonstrated more concretely. However, the present invention is not limited to this.

(Review 1)

1-1. Synthesis of Amine Adduct Particles

Amine Adduct Particles 1

2-methylimidazole 288.2 g of a solution containing 1-butanol and toluene mixed at 1/1 (wt / wt) in a 3000 mL three-neck separable flask equipped with a cooling tube, an isostatic dropping funnel and a stirring device. g was added and heated to 80 ° C. in an oil bath while stirring to dissolve 2-methylimidazole. Next, a solution in which 946 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolysis chlorine amount 0.01% by weight) was dissolved in 300 g of a mixed solvent in which 1-butanol and toluene were mixed at 1/1 (wt / wt). Was added dropwise for 90 minutes using an isostatic dropping funnel. After completion of dropwise addition, heating was performed at 80 ° C for 5 hours. Then, it heated up to 180 degreeC and pressure-reduced the inside of an apparatus until finally pressure became 10 mmHg or less. After the pressure became 10 mmHg or less, the solvent was further distilled off by heating under reduced pressure for 2 hours to obtain a dark red brown viscous liquid. This viscous liquid was cooled to room temperature to obtain a dark reddish brown solid amine adduct. This amine adduct was ground with a jet mill to obtain amine adduct particles 1 having an average particle size of 1.96 탆.

Amine Adduct Particles 2

Amine adduct having an average particle diameter of 1.88 占 퐉 in the same manner as in Amine Adduct Particle 1, except that the bisphenol A type epoxy resin was changed to 874 g of a bisphenol F type epoxy resin (160 g / eq of epoxy equivalent, 0.007% by weight of hydrolyzed chlorine). Particle 2 was obtained.

1-2. Synthesis of Microcapsule-type Latent Curing Agent

Microcapsule latent hardeners 1

45.0 g of amine adduct particles 1 and 171.0 g of cyclohexane were added to a 500 mL three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 40 ° C., followed by 1.2 g of water. After stirring for 10 minutes, 3.0 g of 4,4'- diphenylmethane diisocyanate was added and it reacted at 40 degreeC for 2 hours. Then, it heated up at 50 degreeC and made it react for 6 hours. After the reaction was completed, the dispersion was filtered, and the recovered powder was washed with cyclohexane heated to 50 ° C. The solvent was removed from the obtained powder by the pressure reduction drying for 24 hours at the pressure of 10 mmHg or less, and the microcapsule type latent hardener 1 was obtained.

Microencapsulated Latent Curing Agent 2

The microcapsule-type latent curing agent 2 was obtained like Example 1 except having used the amine adduct particle 2 instead of the amine adduct particle 1.

Microencapsulated latent curing agent 3 (recapsulation of microencapsulated latent curing agent 1)

146.3 g of toluene and 2.5 g of 4,4'-diphenylmethane diisocyanate were added to a 500 mL three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 50 ° C in an oil bath. Subsequently, 15.0 g of microcapsule-type latent curing agents (F) 1 were added, and reacted at 50 degreeC for 3 hours. After completion of the reaction, the dispersion was filtered and the recovered powder was washed with toluene heated to 50 ° C. The solvent was removed from the obtained powder by pressure-drying for 24 hours at the pressure of 10 mmHg or less, and the microcapsule type latent hardener 3 was obtained.

Microcapsules latent curing agent 4 (with ethylene glycol)

45.0 g of amine adduct particles 1 and 171.0 g of cyclohexane were added to a 500 mL three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 40 ° C. Next, 2.0 g of tolylene diisocyanate was added and it heated at 40 degreeC for 2 hours. Furthermore, it heated up at 50 degreeC and added 3.0 g of ethylene glycol over 6 hours. After the reaction was completed, the dispersion was filtered, and the recovered powder was washed with cyclohexane heated to 50 ° C. The solvent was removed from the obtained powder by pressure-drying for 24 hours at the pressure of 10 mmHg or less, and the microcapsule type latent hardener 4 was obtained.

Microcapsule Type Potential Curing Agent 6

45.0 g of amine adduct particles 1 and 171.0 g of cyclohexane were added to a 500 mL three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 40 ° C., followed by 1.2 g of water. After stirring for 10 minutes, 3.0 g of polymer MDI (manufactured by Nippon Polyurethane Co., Ltd., trade name: Milionate MR-200) was added, and the mixture was reacted at 40 ° C for 2 hours. Then, it heated up at 50 degreeC and made it react for 6 hours. After the reaction was completed, the dispersion was filtered, and the recovered powder was washed with cyclohexane heated to 50 ° C. The solvent was removed from the obtained powder by pressure-drying for 24 hours at the pressure of 10 mmHg or less, and the microcapsule type latent hardener 6 was obtained.

1-3. Preparation of One-Component Epoxy Resin Compositions

Examples 1 to 3

33 g of the microcapsule-type latent curing agent 1, 2 or 3 and 67 g of a bisphenol F-type epoxy resin (epoxy equivalent 160 g / eq, amount of hydrolyzed chlorine 0.007% by weight) were mixed to form the one-component epoxy of Examples 1 to 3. The resin composition was obtained.

Example 4

33 g of the microcapsule latent curing agent 4 and 67 g of a bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolysis chlorine amount 0.01 wt%) were blended to obtain a one-component epoxy resin composition.

Example 5

45 g of microcapsule-type latent curing agents 3 and 55 g of bisphenol F-type epoxy resin (160 equivalents of epoxy equivalent, 0.007% by weight of hydrolyzed chlorine) were blended to obtain a one-component epoxy resin composition.

Example 6

35 g of microcapsule latent curing agents 3, 25 g of bisphenol A type epoxy resin (160 g / eq of epoxy equivalent, 0.007 wt% of hydrolyzed chlorine), resorcin diglycidyl ether (117 g / eq of epoxy equivalent), 40 g of hydrolyzed chlorine amount 0.7 wt%) was blended to obtain a one-component epoxy resin composition.

Example 7

33 g of microcapsule-type latent curing agent 1 was added to a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and a bisphenol F-type epoxy resin (160 g / eq epoxy equivalent, 0.007 wt% of hydrolyzed chlorine) was added. 67 g was added and stirred at 50 degreeC for 24 hours, and the one-component epoxy resin composition was obtained.

Example 8

A one-component epoxy resin composition was obtained in the same manner as in Example 7 except that the microcapsule latent curing agent 2 was used instead of the microcapsule latent curing agent 1.

1-4. Characterization of Microcapsule-type Latent Curing Agent

The hardening characteristic and storage stability of the one-component epoxy resin composition of Examples 1-8, and the average particle diameter of the amine adduct particle 1, 2 were evaluated by the following method. The results are summarized in Table 1.

Curing properties

About the one-component epoxy resin composition, the effect characteristic was measured in the temperature increase rate of 10 degree-C / min, the measurement temperature range of 30 degreeC-300 degreeC, and nitrogen atmosphere using the DSC7 differential calorimeter by a Perkin-Elmer company. If the temperature of the maximum point of the peak resulting from hardening exotherm is less than 115 degreeC, it is determined as "AA", if it is 115 degreeC or more and less than 120 degreeC, "A", if it is 120 degreeC or more and less than 130 degreeC, it will be determined as "C". It was. The lower the temperature of the maximum point of the peak resulting from hardening heat generation means that the resin composition has excellent low temperature hardenability.

Storage stability

Bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolysis chlorine amount 0.01 weight%) of the same weight was added to the one-component epoxy resin composition, and it stored in the 40 degreeC thermostat. Initially and after 30 days, the viscosity at 25 ° C. of the one-component epoxy resin composition was measured using an E-type viscometer. Storage stability was judged by the rate of viscosity increase from the beginning after 30 days. Viscosity measurement is performed using a cone of 3 ° (angle), 10 rpm when the viscosity is 3 to 40 Pa · s, 2.5 rpm when the viscosity is 40 to 200 Pa · s, 0.5 rpm when the viscosity is 200 to 1000 Pa · s The rotation was performed at. It was determined that "AA" if the viscosity increase rate after 30 days was 25% or less, "A" if 50% or less, "B" if less than 100%, and "C" if 100% or more.

Average particle diameter

The average particle diameter of amine adduct particle | grains was measured 3 times using the laser diffraction type particle size distribution measuring apparatus (Master sizer 2000: dry measuring unit Scirocco 2000) by Malvern. The average value of the 50% diameter (median diameter) at this time was made into the average particle diameter.

Hereinafter, a microcapsule-type latent curing agent and a one-component epoxy resin composition for a comparative example were prepared.

Synthesis of Microencapsulated Latent Curing Agent 5

45.0 g of amine adduct particles 1 and 171.0 g of cyclohexane were added to a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 40 ° C., followed by stirring for 10 minutes. Then, 3.0 g of 4,4'- diphenylmethane diisocyanate was added and it reacted at 40 degreeC for 2 hours. Then, it heated up at 50 degreeC and made it react for 6 hours. After the reaction was completed, the dispersion was filtered, and the recovered powder was washed with cyclohexane heated to 50 ° C. The solvent was removed from the obtained powder by pressure-drying for 24 hours at the pressure of 10 mmHg or less, and the microcapsule type latent hardener 5 was obtained.

Comparative Example 1

33 g of the microcapsule-type latent curing agent 5 and 67 g of bisphenol F-type epoxy resin (epoxy equivalent 160 g / eq, amount of hydrolyzed chlorine) were combined to obtain a one-component epoxy resin composition.

Comparative Example 2

45 g of amine adduct particles 1 and 55 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolysis chlorine amount 0.01% by weight) were added to a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, After heating to 40 ° C., 0.5 g of water were added. After stirring for 10 minutes, 4.0 g of 4,4'-diphenylmethane diisocyanate was added and it heated at 40 degreeC for 2 hours. Subsequently, when heated up at 50 degreeC and heated for 6 hours, hardening reaction advanced in the flask and the one-component epoxy resin composition was not obtained.

Comparative Example 3

To a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, 33 g of amine adduct particles 1 and 67 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolysis chlorine amount 0.01 wt%) were added thereto. After heating to 40 ° C., 0.5 g of water were added. After stirring for 10 minutes, 4.0 g of 4,4'-diphenylmethane diisocyanate was added and it heated at 40 degreeC for 2 hours. Subsequently, it heated up at 50 degreeC and heated for 6 hours, and obtained one-component epoxy resin composition.

The curing characteristics and storage stability of the one-component epoxy resin compositions of Comparative Examples 1 and 3 and the microcapsule-type latent curing agent 5 were evaluated by the same method as described above.

Comparison of characteristic changes between lots

About the epoxy resin composition of Example 1, 3 and the comparative example 1, the same experiment was repeated 5 times from the synthesis | combination of a microcapsule type latent hardener to manufacture of a resin composition, and the variation of initial viscosity was examined. As the one-component epoxy resin composition of Example 1, the value obtained by dividing the maximum value of the initial viscosity by the minimum value was 1.3, and the standard deviation when the minimum viscosity value was 1 was 0.012 with little variation and was good. In the one-component epoxy composition of Example 3, the value obtained by dividing the maximum value of the initial viscosity by the minimum value was 1.2, and the standard deviation when the minimum viscosity value was 1 was 0.007, which was small and good. On the other hand, in the one-component epoxy resin composition of Comparative Example 3, the value obtained by dividing the maximum value of the initial viscosity by the minimum was 3.6, and the standard deviation when the minimum viscosity value was 1 was largely 0.78.

The above evaluation results were put together in Table 1 and shown.

As is clear from the results shown in Table 1, it was confirmed that by using the microcapsule-type latent curing agent according to the present invention, a one-component epoxy resin composition having sufficient low temperature curing characteristics and excellent storage stability was obtained.

Example 9

30 g of microcapsule latent curing agent 1, 50 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq., Hydrolyzable chlorine amount 0.01 mass%) and bisphenol F type epoxy resin (epoxy equivalent 160 g / eq., 20 g of hydrochloric acid amount 0.007 mass%) was blended to obtain a one-component epoxy resin composition of Example 9.

Example 10, 11

30 g of microcapsule-type latent curing agents 3 or 6, 50 g of bisphenol F-type epoxy resin (160 g / eq of epoxy equivalent, 0.007 mass% of hydrolyzed chlorine), and bisphenol A type epoxy resin (173 g / eq of epoxy equivalent). And 20 g of hydrolyzable chlorine amount (0.01% by mass) were combined to obtain the one-component epoxy resin compositions of Examples 10 and 11.

Comparative Example 4

30 g of amine adduct particle 1 and 50 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq., Hydrolyzable chlorine amount 0.01 mass%) and bisphenol in a three-neck separable flask equipped with a cooling tube, a thermocouple and a stirring device. 20 g of an F-type epoxy resin (160 g / eq epoxy equivalent, 0.007 mass% of hydrolyzed chlorine) was added thereto, and the mixture was heated to 40 ° C and 0.5 g of water was added thereto. After stirring for 10 minutes, 3.0 g of 4,4'-diphenylmethane diisocyanate was added and it heated at 40 degreeC for 2 hours. Subsequently, it heated up at 50 degreeC and heated for 6 hours, and obtained one-component epoxy resin composition.

Comparative Example 5

30 g of amine adduct particle 1, 50 g of bisphenol F type epoxy resin (epoxy equivalent 160 g / eq, hydrochloric acid amount 0.007 mass%) and bisphenol A in a three-neck separable flask equipped with a cooling tube, a thermocouple and a stirring device. 20 g of a type epoxy resin (epoxy equivalent 173 g / eq., Hydrolyzable chlorine amount 0.01 mass%) was added, and after heating to 40 degreeC, 0.5 g of water was added. After stirring for 10 minutes, 3.0 g of polymeric MDI (manufactured by Nippon Polyurethane Co., Ltd., trade name: Milionate MR-200) was added thereto, and the mixture was heated at 40 ° C for 2 hours. Subsequently, it heated up at 50 degreeC and heated for 6 hours, and obtained one-component epoxy resin composition.

As is clear from the results shown in Table 2, not only sufficient low-temperature curing characteristics and excellent storage stability are obtained by using the microcapsule-type latent curing agent according to the present invention, but also when compared with epoxy resins of the same composition, It was confirmed that a lower viscosity is achieved than the adduct particles, that is, higher fluidity is achieved.

(Review 2)

2-1. Synthesis of Amine Adduct Particles

Amine Adduct Particles 3

336.4 g of 2-methylimidazole in 824.2 g of a solution of 1-butanol and toluene mixed at 1/1 (wt / wt) in a 3000 mL three-neck separable flask equipped with a cooling tube, an isostatic dropping funnel and a stirring device. Was added and heated to 80 ° C. in an oil bath while stirring to dissolve 2-methylimidazole. Subsequently, a solution obtained by dissolving 945.8 g of a bisphenol A-type epoxy resin (epoxy equivalent 173 g / eq, hydrochloric acid amount 0.01 mass%) in 300 g of 1-butanol and toluene 1/1 (wt / wt) solution was subjected to an isostatic dropping funnel. It was dripped over 90 minutes. After completion of dropwise addition, heating was performed at 80 ° C for 5 hours. Then, it heated up to 180 degreeC and pressure-reduced the inside of an apparatus until the pressure finally became 10 mmHg or less. The solvent was distilled off. After the pressure became 10 mmHg or less, the solvent was further distilled off by heating under reduced pressure for 2 hours to obtain a dark red brown viscous liquid. This viscous liquid was cooled to room temperature to obtain a dark reddish brown solid amine adduct. This amine adduct was ground with a jet mill to obtain amine adduct particles 3 having an average particle diameter of 2.50 탆.

Amine Adduct Particles 4

Amine adduct having an average particle size of 3.14 μm in the same manner as in Amine Adduct Particle 1, except that the bisphenol A type epoxy resin was changed to 874 g of a bisphenol F type epoxy resin (160 g / eq of epoxy equivalent, 0.007 mass% of hydrolyzed chlorine). Particle 4 was obtained.

2-2. Synthesis of Microcapsule-type Latent Curing Agent

Microencapsulated Latent Curing Agents 7

45.0 g of amine adduct particles 1 and 171.0 g of cyclohexane were added to a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 40 ° C., and then 1.1 g of water was added thereto. After stirring for 10 minutes, 6.0 g of 4,4'- diphenylmethane diisocyanate was added and it reacted at 40 degreeC for 2 hours. Then, it heated up at 50 degreeC and made it react for 6 hours. After the reaction was completed, the dispersion was filtered, and the recovered powder was washed with cyclohexane heated to 50 ° C. The solvent was removed from the obtained powder by the pressure reduction drying for 24 hours at the pressure of 10 mmHg or less, and powdery microcapsule type latent hardener 7 was obtained. The ratio of the capsule in the obtained microcapsule latent curing agent 7 was 14 mass%.

Microencapsulated Latent Curing Agents 8

45.0 g of amine adduct particles 1 and 171.0 g of cyclohexane were added to a 500 mL three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 40 ° C., and then 1.1 g of water was added thereto. Next, 3.0 g of 4,4'- diphenylmethane diisocyanate was added and it reacted at 40 degreeC for 2 hours. Furthermore, it heated up at 50 degreeC and made it react for 6 hours. After the reaction was completed, the dispersion was filtered, and the recovered powder was washed with toluene. The solvent was removed from the obtained powder by the pressure reduction drying for 24 hours at the pressure of 10 mmHg or less, and the powdery microcapsule type latent hardener 8 was obtained. The ratio of the capsule in the obtained microcapsule latent curing agent 8 was 9 mass%.

Microencapsulated Latent Curing Agent 9

45.0 g of amine adduct particles 2 and 171.0 g of cyclohexane were added to a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 40 ° C., and then 1.1 g of water was added thereto. After stirring for 10 minutes, 6.0 g of 4,4'- diphenylmethane diisocyanate was added and it reacted at 40 degreeC for 2 hours. Then, it heated up at 50 degreeC and made it react for 6 hours. After the reaction was completed, the dispersion was filtered, and the recovered powder was washed with cyclohexane heated to 50 ° C. The solvent was removed from the obtained powder by pressure-drying for 24 hours at the pressure of 10 mmHg or less, and the powdery microcapsule type latent hardener 9 was obtained. The ratio of the capsule in the obtained microcapsule latent curing agent 9 was 15 mass%.

Microencapsulated latent curing agent 10 (recapsulation of microencapsulated latent curing agent 7)

146.3 g of toluene and 3.7 g of 4,4'-diphenylmethane diisocyanate were added to a 500 mL three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 50 ° C in an oil bath. Subsequently, 15.0 g of microcapsule latent curing agents 7 were added, and the mixture was reacted at 50 ° C for 3 hours. After completion of the reaction, the dispersion was filtered and the recovered powder was washed with toluene heated to 50 ° C. The solvent was removed by drying under reduced pressure for 24 hours at a pressure of 10 mmHg or less to obtain a powdery microcapsule-type latent curing agent 10. The ratio of the capsule in the obtained microcapsule latent curing agent 10 was 45 mass%.

Microencapsulated latent curing agent 11 (recapsulation of microencapsulated latent curing agent 7)

146.3 g of toluene and 1.8 g of 4,4'-diphenylmethane diisocyanate were added to a 500 mL three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 50 ° C in an oil bath. Subsequently, 15.0 g of microcapsule latent curing agents 7 were added, and the mixture was reacted at 50 ° C for 3 hours. After completion of the reaction, the dispersion was filtered and the recovered powder was washed with toluene heated to 50 ° C. The solvent was removed from the obtained powder by the pressure reduction drying for 24 hours at the pressure of 10 mmHg or less, and the powdery microcapsule type latent hardener 11 was obtained. The ratio of the capsule of the obtained microcapsule latent curing agent 11 was 28 mass%.

2-3. Preparation of One-Component Epoxy Resin Compositions

Examples 12-16

33 g of microcapsule-type latent curing agents 7 to 11 and 67 g of bisphenol F type epoxy resin (160 g / eq of epoxy equivalent, 0.007 mass% of hydrolyzed chlorine) were mixed together to form the one-component epoxy resin of Examples 12 to 16. A composition was obtained.

Example 17

33 g of the microcapsule-type latent curing agent 10 and 67 g of a bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolysis chlorine amount 0.01 mass%) were blended to obtain a one-component epoxy resin composition of Example 17.

Example 18

33 g of the microcapsule latent curing agent 10 and 67 g of a naphthalene type epoxy resin (epoxy equivalent 142 g / eq, hydrolysis chlorine amount 0.017 mass%) were blended to obtain the one-component epoxy resin composition of Example 18.

Example 19

35 g of microcapsule latent curing agents 10, 25 g of bisphenol F-type epoxy resin (160 g / eq of epoxy equivalent, 0.007 mass% of hydrolyzed chlorine), and resorcindiglycidyl ether (117 g of epoxy equivalent) 40 g of eq and 0.7 mass% of hydrolyzed chlorine) were mix | blended, and the one-component epoxy resin composition of Example 19 was obtained.

2-4. Microcapsule type latent curing agent and one-component epoxy resin composition for comparison

Synthesis of Microencapsulated Latent Curing Agent 12

45.0 g of amine adduct particles 1 and 171.0 g of cyclohexane were added to a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, and heated to 40 ° C., followed by stirring for 10 minutes. Thereafter, 1.0 g of 4,4'-diphenylmethane diisocyanate was added and reacted at 40 ° C for 2 hours. Then, it heated up at 50 degreeC and made it react for 6 hours. After the reaction was completed, the dispersion was filtered, and the recovered powder was washed with cyclohexane heated to 50 ° C. The solvent was removed from the obtained powder by pressure-drying for 24 hours at the pressure of 10 mmHg or less, and the microcapsule type latent hardener 12 was obtained. The ratio of the capsule of the obtained microcapsule latent curing agent 12 was 3 mass%.

Comparative Example 6

33 g of the microcapsule-type latent curing agent 12 and 67 g of a bisphenol F-type epoxy resin (160 equivalents of epoxy equivalent, 0.007 mass% of hydrolyzed chlorine) were blended to obtain a one-component epoxy resin composition of Comparative Example 6.

Comparative Example 7

45 g of amine adduct particles 1 and 55 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolysis chlorine amount 0.01 mass%) were added to a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device, After heating to 40 ° C., 0.5 g of water were added. After stirring for 10 minutes, 4.0 g of 4,4'-diphenylmethane diisocyanate was added and it heated at 40 degreeC for 2 hours. Subsequently, when heated up at 50 degreeC and heated for 6 hours, hardening reaction advanced in the flask and the one-component epoxy resin composition was not obtained.

Comparative Example 8

45 g of amine adduct particle 1 and 55 g of bisphenol F-type epoxy resin (160 g / eq epoxy equivalent, 0.007 mass% of hydrolyzed chlorine) were added to a three-neck separable flask equipped with a cooling tube, a thermocouple, and a stirring device. The hardening reaction advanced in the flask and the one-component epoxy resin composition was not obtained.

2-5. Characterization of Microcapsule-type Latent Curing Agent

The hardening characteristic and storage stability of the one-component epoxy resin composition of an Example and a comparative example and the average particle diameter of amine adduct particle 3, 4 were evaluated by the following method. The results are summarized in Table 3.

Curing properties

About one-component epoxy resin composition, hardening characteristic was measured in the temperature increase rate of 10 degree-C / min, the measurement temperature range of 30 degreeC-300 degreeC, and nitrogen atmosphere using the Perkin-Elmer DSC7 differential calorimeter. If the temperature of the maximum point of the peak resulting from hardening exotherm is less than 110 degreeC, it is determined as "AA", if it is 110 degreeC or more and less than 125 degreeC, "A", if it is 125 degreeC or more and less than 135 degreeC, it will be determined as "C". It was.

Storage stability

The storage stability of the epoxy resin composition and the average particle diameter of the amine adduct particles were measured in accordance with the same measurement conditions and criteria as in the case of study 1.

Ratio of capsules

The dispersion prepared by adding a sufficient amount of methanol to the microcapsule latent curing agent was stirred at room temperature for 6 hours to dissolve the portion derived from the amine adduct particles in the microcapsule latent curing agent in methanol. The dispersion was filtered and the filtrate was dried at a temperature below 50 ° C. to remove methanol completely. The weight of the filtrate after drying was measured. The ratio of the weight of the filtrate to the total weight of the curing agent for the microcapsule type epoxy resin was regarded as the ratio of the capsules.

Content-based

A mixture of one-component epoxy resin composition / solvent = 15 g / 3.5 g was maintained in a water bath at 40 ° C. using toluene / ethyl acetate = 1/1 (wt / wt) as a solvent, and the viscosity change of the mixture at that time was observed. Observed. It was determined that the time when the fluidity disappeared was "C" for 0 to 3 hours, "B" for 3 to 6 hours, "A" for 6 to 10 hours, and "AA" for 10 hours or more.

2-6. result

The evaluation result of an Example and a comparative example was put together in following Table 3, and was shown. In the table | surface, the numerical value in parentheses is a compounding ratio (weight part) of a one-component epoxy resin composition. The content of the symbol in a table | surface is as follows.

BisA: bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolysis chlorine amount 0.01 mass%)

BisF: bisphenol F type epoxy resin (epoxy equivalent 160 g / eq, hydrolysis chlorine amount 0.007 mass%)

Nap: naphthalene type epoxy resin (epoxy equivalent 142 g / eq, hydrolysis chlorine amount 0.017 mass%)

Res: Resorcin diglycidyl ether (epoxy equivalent 117 g / eq, hydrolyzed chlorine amount 0.7 mass%)

Also from the above experimental results, it was confirmed that according to the present invention, a powdery microcapsule-type latent curing agent and production method for epoxy resins compatible with low temperature curability and storage stability and a one-component epoxy resin composition can be obtained.

Claims (13)

A microcapsule type latent curing agent having a core and a capsule covering the same,
The core comprises 50 to 100% of the amine adduct by mass ratio,
The capsule comprises a reaction product of an isocyanate with a compound having an active hydrogen group and / or water, at least a portion of the reaction product being bound to the core by reaction with the amine adduct,
The said amine adduct is obtained by reaction of a polyhydric epoxy compound and an amine compound,
The amine compound is selected from the group consisting of a compound having a primary amino group and / or a secondary amino group and not having a tertiary amino group, a compound having a tertiary amino group and an active hydrogen group,
The isocyanate is selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, low molecular triisocyanates, and polyisocyanates,
A microcapsule-type latent curing agent for epoxy resin in powder form, wherein the ratio of the capsule is 5 to 40% by mass based on the total mass of the microcapsule-type latent curing agent. And reacting the amine adduct contained in the core with the isocyanate compound having an active hydrogen group and / or water in a dispersion medium to form a capsule covering the core.
The core comprises 50 to 100% of the amine adduct in a mass ratio,
The said amine adduct is obtained by reaction of a polyhydric epoxy compound and an amine compound,
The amine compound is selected from the group consisting of a compound having a primary amino group and / or a secondary amino group and not having a tertiary amino group, a compound having a tertiary amino group and an active hydrogen group,
The isocyanate is selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, low molecular triisocyanates, and polyisocyanates,
A method for producing a microcapsule latent curing agent for an epoxy resin in powder form, wherein the capsule is formed so that the ratio of the capsule is 5 to 40% by mass based on the total mass of the microcapsule latent curing agent. The manufacturing method of Claim 2 which further includes the process of taking out the powder-like microcapsule type latent hardener which has a core and a capsule from the mixture after reaction. The microcapsule-type latent hardener for epoxy resins which are powder form obtained by the manufacturing method of Claim 2. The one-pack epoxy resin composition containing the microcapsule type latent hardening | curing agent for epoxy resins of Claim 1, and an epoxy resin. The one-component epoxy resin composition according to claim 5, wherein the powdered microcapsule-type latent curing agent for epoxy resin is heat-treated in the epoxy resin. The one-component epoxy resin composition according to claim 5, which contains 5 to 70 parts by mass of the microcapsule-type latent curing agent based on 100 parts by mass of the total amount of the epoxy resin and the microcapsule-type latent curing agent. Hardened | cured material formed by hardening | curing the one-component epoxy resin composition of Claim 5 by heating. delete delete delete delete delete