JP2009102610A - Microcapsule type latent curing agent for epoxy resin, method for producing the same, one-component epoxy resin composition, and epoxy resin cured product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curing agent for an epoxy resin satisfying both of low temperature curing property and storage stability, to provide a method for manufacturing the curing agent for an epoxy resin, to provide a one-component epoxy resin composition using the curing agent for an epoxy resin, and to provide an epoxy resin cured product. <P>SOLUTION: The microcapsule type latent curing agent for an epoxy resin comprises: a core including an amine adduct of 60 to 99.99 mass% and at least one kind of nitrogen-containing compound of 0.01 to 40 mass% selected from a compound having a primary amino group and/or a secondary amino group and an imidazole compound; and a capsule which is disposed so as to cover the core and is formed to cause the core to react with an isocyanate and water and/or a compound having an active hydrogen group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Epoxy resin has excellent performance in terms of mechanical properties, electrical properties, thermal properties, chemical resistance, adhesiveness, etc., and it can be used for paints, insulating materials for electrical and electronic materials, adhesives, etc. It is used for a wide range of applications.

  The epoxy resin composition generally used conventionally is a so-called two-component type in which two components of an epoxy resin and a curing agent are mixed at the time of use. The two-part epoxy resin composition can be cured at room temperature, but it is necessary to store the epoxy resin and the curing agent separately and weigh and mix them as necessary. It is. In addition, since the usable time is limited, it cannot be mixed in a large amount in advance, the blending frequency increases, and a reduction in efficiency is inevitable.

Therefore, several one-component epoxy resin compositions have been proposed so far in order to solve the problem of the two-component epoxy resin blended product. For example, there is an epoxy resin blended with a latent curing agent such as dicyandiamide, BF ₃ -amine complex, amine salt, or modified imidazole compound.

  However, in the case of these latent curing agents, there is room for improvement in terms of achieving both high curability and excellent storage stability. That is, those having excellent storage stability have low curability and require high temperature or a long time for curing. On the other hand, those having high curability have low storage stability and need to be stored at a low temperature such as -20 ° C. More specifically, the storage stability of the dicyandiamide compound is 6 months or more when stored at room temperature, but a curing temperature of 170 ° C. or more is required. When a curing accelerator is used in combination to lower the curing temperature, for example, curing at 130 ° C. is possible, but on the other hand, storage stability at room temperature becomes insufficient, and storage at low temperature is unavoidable. .

  Moreover, when obtaining a film-shaped molded product or a product in which a base material is impregnated with an epoxy resin, it is often a compounded product containing a solvent, a reactive diluent and the like. Therefore, when a conventional latent curing agent is used as a curing agent for such a blended product, the storage stability is extremely lowered and it is necessary to make it substantially two-component.

  Under such a background, studies have been made to react the surface of a powdered amine compound with an isocyanate compound to inactivate the surface of the amine compound and impart a latent property (see, for example, Patent Documents 1 to 5). ).

In addition, studies have been made to encapsulate a powdered amine compound by reacting with an isocyanate in an epoxy compound to form a single component (see, for example, Patent Documents 6 to 8).
Japanese Patent Publication No.58-55970 JP 59-27914 A JP 59-59720 A European Patent Publication No. 193,068 JP-A-61-190521 JP-A-1-70523 JP 2004-269721 A JP 2005-344046 A

  However, even the methods described in Patent Documents 1 to 8 still have room for improvement in order to be put to practical use.

  First, the methods described in Patent Documents 1 to 5 are surface treatment of a powdered amine compound, and the storage stability is not sufficient. In addition, when the amine compound after the surface treatment is uniformly dispersed in the epoxy resin, there is a problem that a shearing force is received by an apparatus such as a roll, the surface layer is destroyed, and storage stability is impaired.

  In recent years, in order to improve productivity in electronic material applications, further improvements in curing characteristics and storage stability have been demanded for one-part resin compositions. Even with this method, it is not always easy to meet such a requirement. In the methods of Patent Documents 6 to 8, it is possible to improve the curing characteristics by increasing the amount of the microcapsule-type latent curing agent (F). However, in order to increase the amount of the microcapsule-type latent curing agent, it is necessary to add a large amount of a powdery amine compound in the epoxy, and it becomes difficult to perform a uniform encapsulation reaction as the viscosity increases. For this reason, there is a problem that the variation in characteristics between lots becomes large and the defect rate of the product becomes high, and the encapsulation does not proceed sufficiently and cannot be compatible with the storage stability.

  As another method, it is conceivable to increase the reactivity with the epoxy resin in order to enhance the curing characteristics of the component that becomes the core. However, in this case as well, there is a problem that the curing reaction proceeds in the epoxy resin and a latent curing agent having sufficient characteristics cannot be synthesized.

  The present invention has been made in view of such circumstances, and uses a curing agent for epoxy resins capable of achieving both low-temperature curability and storage stability, a method for producing the same, and the curing agent for epoxy resins. It is an object of the present invention to provide a one-component epoxy resin composition and a cured epoxy resin.

  In order to solve the above-mentioned problems, the present invention provides at least one nitrogen-containing compound selected from amine adducts 60 to 99.99% by mass, a compound having a primary amino group and / or a secondary amino group, and an imidazole compound. A core containing 0.01 to 40% by mass; a capsule provided so as to cover the core; and a capsule formed by reacting the core with isocyanate and water and / or a compound having an active hydrogen group A microcapsule type latent curing agent for epoxy resin (hereinafter, sometimes referred to as “the curing agent of the present invention”).

  In the hardening | curing agent of this invention, it is preferable that melting | fusing point of the said nitrogen-containing compound is 40 to 200 degreeC.

  Moreover, it is preferable that the hardening | curing agent of this invention contains the aromatic amine which has a primary and / or a secondary amino group as a nitrogen-containing compound. Furthermore, the aromatic amine is preferably at least one selected from diaminodiphenylmethane and metaphenylenediamine.

  In the dispersion medium having a boiling point of 150 ° C. or less at 1 atm and a viscosity of 1000 mPa · s or less at 25 ° C., the amine adduct is 60 to 99.99% by mass, and a primary amino group and / or secondary. A core containing 0.01 to 40% by mass of at least one nitrogen-containing compound selected from a compound having an amino group and an imidazole compound, an isocyanate and a compound having water and / or an active hydrogen group are reacted with each other. A method for producing a microcapsule-type latent curing agent for epoxy resin is provided, which includes a step of forming a capsule covering the substrate and removing a dispersion medium to obtain a microcapsule-type latent curing agent for epoxy resin.

  The present invention also provides a one-component epoxy resin composition containing the microcapsule-type latent curing agent of the present invention and an epoxy resin.

  In the one-component epoxy resin composition of the present invention, the microcapsule-type latent curing agent is preferably one that has been heated in the epoxy resin at a temperature equal to or lower than the melting point or softening point of the core component.

  Moreover, this invention provides the epoxy resin hardened | cured material obtained by heating the said one-component epoxy resin composition of this invention.

  ADVANTAGE OF THE INVENTION According to this invention, the hardening | curing agent for epoxy resins which can make low temperature curability and storage stability compatible, its manufacturing method, and the one-pack epoxy resin composition and epoxy resin using this hardening | curing agent for epoxy resins A cured product is provided. The curing agent and the production method thereof, the one-part epoxy resin composition, and the epoxy resin cured product of the present invention are useful from the viewpoint of improving productivity in fields such as electronic material applications.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The curing agent of the present invention contains at least one nitrogen-containing compound 0.01 to 40 selected from amine adducts 60 to 99.99% by mass, a compound having a primary amino group and / or a secondary amino group, and an imidazole compound. A core containing mass% and a capsule formed so as to cover the core and formed by reacting the core with an isocyanate and water and / or a compound having an active hydrogen group are provided.

  The content of the amine adduct in the core is 60 to 99.99% by mass, preferably 70 to 99% by mass, and more preferably 80 to 97% by mass. When the content of the amine adduct in the core is less than 60%, it is difficult to achieve both curing characteristics and storage stability.

  An amine adduct is a compound having an amino group obtained by reacting an epoxy resin with an amine compound.

  As the epoxy resin constituting the amine adduct, either a monoepoxy compound, a polyvalent epoxy compound, or a mixture thereof is used. Monoepoxy compounds include butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, para-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, paraxyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl Examples include hexoate and glycidyl benzoate. Examples of the polyvalent epoxy compound include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol F, tetramethyl bisphenol AD, tetramethyl bisphenol S, tetrabromobisphenol A, and tetrachlorobisphenol A. Bisphenol-type epoxy resin obtained by glycidylation of bisphenols such as tetrafluorobisphenol A; epoxy obtained by glycidylation of other dihydric phenols such as biphenol, dihydroxynaphthalene and 9,9-bis (4-hydroxyphenyl) fluorene Resin; 1,1,1-tris (4-hydroxyphenyl) methane, 4,4- (1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl ) Ethylidene) Epoxy resin glycidylated trisphenols such as bisphenol; Epoxy resin glycidylated tetrakisphenols such as 1,1,2,2, -tetrakis (4-hydroxyphenyl) ethane; Phenol novolac, Cresol novolac , Novolak-type epoxy resins obtained by glycidylating novolaks such as bisphenol A novolak, brominated phenol novolak, brominated bisphenol A novolak, etc .; epoxy resins obtained by glycidylating polyhydric phenols, polyhydric alcohols such as glycerin and polyethylene glycol Glycidylated aliphatic ether type epoxy resin; ether ester type epoxy resin obtained by glycidylation of hydroxycarboxylic acid such as p-oxybenzoic acid and β-oxynaphthoic acid; phthalic acid, Glycidyl type, such as ester type epoxy resin obtained by glycidylation of polycarboxylic acid such as phthalic acid; Glycidylated product of amine compound such as 4,4-diaminodiphenylmethane and m-aminophenol, and amine type epoxy resin such as triglycidyl isocyanurate Examples include epoxy resins and alicyclic epoxides such as 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate.

  As an epoxy resin, since the storage stability of an epoxy resin composition can be improved, a polyvalent epoxy compound is preferable. As the polyvalent epoxy compound, a glycidyl type epoxy resin is preferable because the productivity of the amine compound is overwhelmingly high, and an epoxy resin obtained by glycidylating polyhydric phenols is more preferable because the cured product has excellent adhesion and heat resistance. Preferably, a bisphenol type epoxy resin is more preferable, an epoxy resin obtained by glycidylation of bisphenol A and an epoxy resin obtained by glycidylation of bisphenol F are more preferable, and an epoxy resin obtained by glycidylation of bisphenol A is particularly preferable. These epoxy resins may be used alone or in combination.

  As the amine compound constituting the amine adduct, (a1) a compound having at least one primary amino group and / or secondary amino group and having no tertiary amino group (hereinafter referred to as “amine compound (a1) And (a2) a compound having at least one tertiary amino group and at least one active hydrogen group (hereinafter referred to as “amine compound (a2)”).

  Examples of the amine compound (a1) include methylamine, ethylamine, propylamine, butylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, ethanolamine, propanolamine, cyclohexylamine, isophoronediamine, aniline, toluidine, diamino. Primary amines having no tertiary amino group such as diphenylmethane and diaminodiphenylsulfone; dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dimethanolamine, diethanolamine, dipropanolamine, dicyclohexylamine , Piperidine, piperidone, diphenylamine, phenylmethylamine, phenylethylamine, etc. And the like secondary amine having no grade amino group.

  In the amine compound (a2), examples of the active hydrogen group include a primary amino group, a secondary amino group, a hydroxyl group, a thiol group, a carboxylic acid, and a hydrazide group.

  Examples of the amine compound (a2) include 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol, 1-butoxymethyl-2-dimethyl. Amino alcohols such as aminoethanol, methyldiethanolamine, triethanolamine, N-β-hydroxyethylmorpholine; 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-methylimidazole, 1- (2-hydro Ci-3-phenoxypropyl) -2-methylimidazole, 1- (2-hydroxy-3-phenoxypropyl) -2-ethyl-4-methylimidazole, 1- (2-hydroxy-3-butoxypropyl) -2- Imidazoles such as methylimidazole and 1- (2-hydroxy-3-butoxypropyl) -2-ethyl-4-methylimidazole; 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, 1,3,3-trimethyl-1,4-tetramethylene-bis-4-methylimidazoline, 1,2-phenylene-bis-imidazoline, 1,3 -Imazolines such as phenylene-bis-imidazoline, 1,4-phenylene-bis-imidazoline, 1,4-phenylene-bis-4-methylimidazoline, dimethylaminopropylamine, diethylaminopropylamine, dipropylaminopropylamine, dibutyl Aminopropylamine, dimethylaminoethylamine, diethylamino Tertiary amines such as tilamine, dipropylaminoethylamine, dibutylaminoethylamine, N-methylpiperazine, N-aminoethylpiperazine, diethylaminoethylpiperazine; 2-dimethylaminoethanethiol, 2-mercaptobenzimidazole, 2-mercaptobenzo Amino mercaptans such as thiazole, 2-mercaptopyridine, 4-mercaptopyridine; aminocarboxylic acids such as N, N-dimethylaminobenzoic acid, N, N-dimethylglycine, nicotinic acid, isonicotinic acid, picolinic acid; N, Examples thereof include aminohydrazides such as N-dimethylglycine hydrazide, nicotinic acid hydrazide, and isonicotinic acid hydrazide.

  The amine compound constituting the amine adduct is preferably an amine compound (a2), more preferably an imidazole, and 2-methylimidazole, 2-ethyl-4-, because of its excellent balance between storage stability and curability. Methylimidazole is more preferred.

  In addition to the amine adduct, the core contains 0.01 to 40% by mass of at least one nitrogen-containing compound selected from a compound having a primary and / or secondary amino group and an imidazole compound. When the core contains 0.01 to 40% by mass of the nitrogen-containing compound, both low-temperature curability and storage stability can be achieved.

  The content of the nitrogen-containing compound in the core is more preferably 0.1 to 30% by mass, still more preferably 0.5 to 20% by mass, and most preferably 1 to 15% by mass. The core may simultaneously contain two or more selected from a compound having a primary and / or secondary amino group and an imidazole compound.

  The melting point of the nitrogen-containing compound is preferably 40 ° C to 200 ° C. Below 40 ° C., encapsulation is difficult, and even if encapsulation is possible, there is a possibility that the storage stability of a one-part epoxy resin may be impaired. Above 200 ° C., there is little contribution to low-temperature curability as an epoxy resin curing agent. A more preferable range of the melting point is 60 ° C to 180 ° C, still more preferably 60 ° C to 160 ° C, and most preferably 60 ° C to 150 ° C.

  Examples of the compound having a primary and / or secondary amino group (the temperature in parentheses represents the melting point) are 4,4′-diaminodiphenylmethane (89 ° C.), 3,3′-diaminodiphenylmethane (86 ° C.), 3 , 4′-diaminodiphenylmethane (86 ° C.), 2,2-bis (4- [4-aminophenoxy] phenyl) propane, 3,3′- or 4,4′-diaminodiphenyl sulfone (170-180 ° C.), 3,3′- or 4,4′-diaminodiphenyl ether (180-190 ° C.), 3,3′- or 4,4′-diaminodiphenyl sulfide (108 ° C.), 3,3′- or 4,4′- Diaminodiphenyl ketone (245 ° C), 2,4-toluenediamine (98 ° C), 1,3-phenylenediamine (65 ° C), 1,4-phenylenediamine (142 ° C), 2,2-bis (4-aminophenyl) hexafluoropropane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 9,9-bis (4-aminophenyl) fluorene, o-toluidine Sulfone, 4,4′-diaminobenzanilide (215 ° C.), 9,10-bis (4-aminophenyl) anthracene, 2,2-bis (4- [3-aminophenoxy] phenyl) sulfone, 2,2- Bis (4- [4-aminophenoxy] phenyl) sulfone, 1,4-bis (4-aminophenoxy) biphenyl, bis (4- [4-aminophenoxy] phenyl) ether, 2,2-bis ([4- (4-Amino-2-trifluorophenoxy)] phenyl) hexafluoropropane, 4,4 ′-[1,4-phenylene (1-methyl ester) Isopropylidene)] - bis (benzenamine) and the like. Also suitable are amino and hydroxyl terminated polyarylene oligomers in which the repeating phenyl groups are separated by ethers, sulfides, carbonyls, sulfones, carbonates or similar groups. Examples of such curing agents are amino- and hydroxyl-terminated polyarylene sulfones, polyarylene ether sulfones, polyether ketones, polyether ether ketones and similar variants.

  Examples of the compound having a primary and / or secondary amino group include 4,4′-diaminodiphenylmethane (89 ° C.), 2,4-toluenediamine (98 ° C.) 1,3-phenylenediamine (65 ° C.), 1,4 -Phenylenediamine (142 ° C.), 3,3′- or 4,4′-diaminodiphenyl sulfide (108 ° C.) is preferable from the viewpoint of achieving both low-temperature curability and storage stability, and has been produced as an epoxy resin curing agent. 4,4′-diaminodiphenylmethane (89 ° C.) and 1,3-phenylenediamine (65 ° C.) are most preferable from the viewpoints of achieving both low-temperature curability and storage stability and reducing production costs.

  Examples of the imidazole compound include 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-aminoethyl-2-methylimidazole, 1- (2 -Hydroxy-3-phenoxypropyl) -2-methylimidazole, 1- (2-hydroxy-3-phenoxypropyl) -2-ethyl-4-methylimidazole, 1- (2-hydroxy-3-butoxypropyl) -2 -Methylimidazole, 1- (2-hydroxy-3-butoxypropyl) -2-ethyl-4-methylimidazole.

  As the imidazole compound, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, and 2-phenylimidazole are preferable from the viewpoint of achieving both low-temperature curability and storage stability, and 2-methylimidazole is most preferable.

  The method for producing the core is not particularly limited, but the amine adduct, the compound having a primary and / or secondary amino group, and at least one nitrogen-containing compound selected from imidazole compounds are uniformly present in the core. It is preferable. As a method for realizing such a distribution, the amine adduct and the nitrogen-containing compound are heated and melted together, mixed well, then cooled to room temperature and pulverized, either one is heated and melted, and the other is dispersed. A method of forming a uniform dispersion, cooling to room temperature, and pulverizing can be applied.

  The powder is preferably in the form of a powder having an average particle diameter of 0.1 to 50 μm, and the average particle diameter is more preferably 0.5 to 10 μm, and further preferably 0.5 to 5 μm. If the average particle size is less than 0.1 μm, it becomes difficult to achieve both curability and storage stability. Moreover, a homogeneous hardened | cured material can be obtained by setting it as 50 micrometers or less. The average particle diameter in the present invention refers to the median diameter. The shape thereof is not particularly limited, and may be either spherical or indeterminate, and spherical is preferable for reducing the viscosity of the one-component epoxy resin composition. Here, the term “spherical” includes not only a true sphere but also a shape in which an irregular corner is rounded. The average particle diameter can be measured with a laser diffraction particle size distribution measuring apparatus.

  In the curing agent of the present invention, a capsule formed by reacting a core, an isocyanate, water, and / or a compound having an active hydrogen group is provided so as to cover the core. By encapsulating in this way, it becomes possible to achieve both storage stability and curing characteristics as a curing agent for epoxy resins.

  The isocyanate may be a compound having one or more isocyanate groups in one molecule, but it is preferable to use a compound having two or more isocyanate groups in one molecule. 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 alicyclic diisocyanates include isophorone diisocyanate, 4-4′-dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1,4-isocyanatocyclohexane, 1,3-bis (isocyanatomethyl) -cyclohexane, 1,3-bis. (2-isocyanatopropyl-2-yl) -cyclohexane and the like can be mentioned. Examples of the aromatic diisocyanate include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, 1,5-naphthalene diisocyanate, and the like. Examples of low molecular weight triisocyanates include 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 1,3,6-hexamethylene triisocyanate, 2,6-diisocyanatohexane Aliphatic triisocyanate compounds such as acid-2-isocyanatoethyl and 2,6-diisocyanatohexanoic acid-1-methyl-2-isocyanatoethyl, alicyclic triisocyanates such as tricyclohexylmethane triisocyanate and bicycloheptane triisocyanate Examples thereof include aromatic triisocyanate compounds such as isocyanate compounds, triphenylmethane triisocyanate, and tris (isocyanatephenyl) thiophosphate. Examples of the polyisocyanate include polymethylene polyphenyl polyisocyanate, polyisocyanate derived from the above diisocyanate, and low molecular triisocyanate. Examples of the polyisocyanate derived from the diisocyanate and triisocyanate include isocyanurate type polyisocyanate, burette type polyisocyanate, urethane type polyisocyanate, allophanate type polyisocyanate, carbodiimide type polyisocyanate and the like. These isocyanate compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the reaction between the core and the isocyanate, the product can be coated on the core surface by the reaction between the active hydrogen group contained in the core and the isocyanate. However, sufficient storage stability cannot be expressed only by the surface coating of the core. During this reaction, by making the compound having water and / or active hydrogen groups present, a surface film is grown to obtain a microcapsule type latent curing agent in which a capsule having sufficient storage stability is formed. it can.

  Examples of the active hydrogen group of the compound having an active hydrogen group include a primary amino group, a secondary amino group, a hydroxyl group, a thiol group, a carboxylic acid, and a hydrazide group. The compound having an active hydrogen group may be a compound having one or more active hydrogen groups in one molecule, but it is preferable to use a compound having two or more active hydrogen groups in one molecule. By using a compound having two or more active hydrogen groups in one molecule, a surface coating can be more reliably grown, and a microcapsule type latent curing agent having a higher level of storage stability is produced. I can do it. Such compounds include hexamethylenediamine, diethylenetriamine, triethylenetetramine, ethanolamine, metaxylenediamine, 1,3-bis (aminomethyl) cyclohexane, isophoronediamine, diaminocyclohexane, phenylenediamine, toluylenediamine, diaminodiphenylmethane, Amines such as diaminodiphenylsulfone, piperazine, benzylamine, cyclohexylamine, polyhydric phenols such as bisphenol A, bisphenol F, bisphenol S, hydroquinone, catechol, resorcinol, pyrogallol, phenol novolac resin, and polyvalents such as trimethylolpropane Polyhydric carboxylic acids such as alcohols, adipic acid and phthalic acid, 1,2-dimercaptoethane, 2-mercaptoethane Lumpur, 1-mercapto-3-phenoxy-2 propanol, mercaptoacetic acid, anthranilic acid, can be exemplified lactic acid and the like. Is mentioned. These can be used in combination.

  The dispersion medium used for the capsule forming reaction is not particularly limited as long as the core does not dissolve, but a dispersion medium having a boiling point of 150 ° C. or less at 1 atm and a viscosity of 1000 mPa · s or less at 25 ° C. is used. preferable. When the boiling point of the dispersion medium exceeds 150 ° C., it becomes difficult to remove the dispersion medium after the capsule forming reaction. Moreover, when the viscosity of a dispersion medium exceeds 1000 mPa * s at 25 degreeC, the viscosity at the time of encapsulation will become high and uniform reaction will become difficult. The capsule forming reaction is preferably performed at a temperature below the melting point or softening point of the core component. The dispersion medium preferably does not contain a substituent having an active hydrogen group or an epoxy group that reacts with an amine adduct. These substituents can inhibit the encapsulation reaction. Preferred examples of the dispersion medium include cyclohexane, hexane, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, isopropyl acetate, and butyl acetate.

  In the dispersion medium, unreacted isocyanate and by-products, water and / or compounds having active hydrogen groups remain and cause a decrease in storage stability of the curing agent. Therefore, the dispersion medium is removed after the capsule formation reaction. It is preferable to do. The method for removing the dispersion medium is not particularly limited, but it is preferable to remove residual substances such as unreacted isocyanate and by-products, water and / or a compound having an active hydrogen group together with the dispersion medium. An example of such a method is removal of the dispersion medium by filtration. Moreover, after removing the dispersion medium, the microcapsule-type latent curing agent is preferably subjected to treatment such as washing and drying. The washing method is not particularly limited, but when removing the residue by filtration, the dispersion medium of the same type as the dispersion medium used for the capsule formation reaction or the curing agent of the present invention (encapsulated adduct obtained by the capsule formation reaction) is not dissolved. It can be washed with other solvents. By such washing, unreacted compounds and the like attached to the surface of the microcapsule type latent curing agent can be removed. The drying method is not particularly limited, but it is preferable to dry at a temperature below the melting point or softening point of the core. Such a method includes drying under reduced pressure. The microcapsule-type latent curing agent after filtration and drying is usually in a powder form. By making it into a powder form, a wide variety of compounds can be blended as the one-component epoxy resin composition (J).

  In the method of encapsulating in an epoxy resin, unreacted isocyanate and by-products, water and / or a compound having an active hydrogen group remain, and storage stability is lowered. Moreover, when powdery amine adduct particles are added at a high concentration, the viscosity becomes remarkably high, a uniform reaction cannot be performed, a difference in characteristics between lots becomes large, and an encapsulation reaction itself cannot be performed. In order to increase the reactivity, if the core is added with a compound that is highly reactive with the epoxy resin or the highly reactive epoxy resin is used as a dispersion medium, the reaction between the core and the epoxy resin will occur. Advances preferentially, making it difficult to produce a microcapsule-type latent curing agent or a one-part epoxy resin composition.

  The encapsulation process may be performed twice or more if necessary. At this time, the core, the isocyanate, and water and / or a compound having an active hydrogen group may be reacted at least once. In other processes, the isocyanate or the compound having water and / or an active hydrogen group is used. You may process using either of these. Encapsulation is preferably performed 5 times or less because the production cost is reduced, and more preferably 3 times or less.

  Next, the one-component epoxy resin composition of the present invention will be described. The one-component epoxy resin composition of the present invention contains the microcapsule-type latent curing agent of the present invention and an epoxy resin.

  As an epoxy resin used for the one-component epoxy resin composition of the present invention, one having an average of two or more epoxy groups in one molecule is preferable. Specifically, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrabromobisphenol A, tetrachlorobisphenol A, tetrafluorobisphenol Bisphenol-type epoxy resin obtained by glycidylation of bisphenols such as A; Epoxy resin obtained by glycidylation of other dihydric phenols such as biphenol, dihydroxynaphthalene and 9,9-bis (4-hydroxyphenyl) fluorene; 1,1-tris (4-hydroxyphenyl) methane, 4,4- (1- (4- (1- (4-hydroxyphenyl) -1-methylethyl) phenyl) ethylidene) bispheno Epoxy resin obtained by glycidylation of trisphenols such as sulfur; epoxy resin obtained by glycidylation of tetrakisphenol such as 1,1,2,2, -tetrakis (4-hydroxyphenyl) ethane; phenol novolak, cresol novolak, bisphenol A Novolac type epoxy resin obtained by glycidylation of novolaks such as novolak, brominated phenol novolak, brominated bisphenol A novolak, etc .; epoxy resin obtained by glycidylation of polyhydric phenols, polyhydric alcohol such as glycerin and polyethylene glycol, etc. Aliphatic ether type epoxy resins; ether ester type epoxy resins obtained by glycidylation of hydroxycarboxylic acids such as p-oxybenzoic acid and β-oxynaphthoic acid; polycarbonates such as phthalic acid and terephthalic acid An ester type epoxy resin obtained by glycidylation of rubonic acid; a glycidyl type epoxy resin such as a glycidated product of an amine compound such as 4,4-diaminodiphenylmethane or m-aminophenol, or an amine type epoxy resin such as triglycidyl isocyanurate; Examples include alicyclic epoxides such as 4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate.

  The one-component epoxy resin composition of the present invention is a combination of the curing agent of the present invention and at least one curing agent selected from the group consisting of acid anhydrides, phenols, hydrazides, and guanidines. can do.

In addition, the one-part epoxy resin composition of the present invention can be used as required by a filler, reinforcing material, filler, conductive fine particles, pigment, organic solvent, reactive diluent, non-reactive diluent, resins, crystallinity. Alcohol, a coupling agent, etc. can further be contained. Examples of the filler include, for example, 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, penton, silica, aerosol, lithopone, barite, titanium dioxide, carbon black, graphite, carbon nanotube, fullerene, iron oxide , Gold, silver, aluminum powder, iron powder, nano-sized metal crystals, intermetallic compounds, and the like, all of which are effectively used depending on the application. Examples of the conductive fine particles include, for example, solder particles, nickel particles, nano-sized metal crystals, metal particles coated with other metals, metal particles such as copper and silver inclined particles, and styrene resin, Examples thereof include particles obtained by coating resin particles such as urethane resin, melamine resin, epoxy resin, acrylic resin, phenol resin, and styrene-butadiene resin with a conductive thin film such as gold, nickel, silver, copper, and solder.
Examples of the organic solvent include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate and the like. Examples of the reactive diluent include butyl glycidyl ether, N, N′-glycidyl-o-toluidine, phenyl glycidyl ether, styrene oxide, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and 1,6-hexanediol diester. A glycidyl ether etc. are mentioned. Examples of non-reactive diluents include dioctyl phthalate, dibutyl phthalate, dioctyl adipate, and petroleum solvents.
Examples of resins include polyester resins, polyurethane resins, acrylic resins, polyether resins, melamine resins, phenoxy resins, urethane-modified epoxy resins, rubber-modified epoxy resins, alkyd-modified epoxy resins, and other modified epoxy resins.
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 of the present invention can be obtained by mixing the curing agent of the present invention, an epoxy resin, and the other components described above with a mixer or a roll.

  In the production of the one-component epoxy resin composition of the present invention, it is preferable that the curing agent of the present invention is preliminarily subjected to a heating treatment in the epoxy resin at the melting point or softening point of the core component. By performing such heat treatment, the epoxy resin (I) is taken into the capsule layer, and the storage stability can be further improved.

  The treatment temperature when the curing agent of the present invention is heat-treated in an epoxy resin is more preferably higher than normal temperature and lower than the melting point (softening point) of the amine adduct. When the temperature is lower than room temperature, there is almost no effect of improving storage stability, and when the temperature is higher than the melting point (softening point) of the amine adduct, the characteristics are likely to deteriorate due to reaction with the epoxy resin. The treatment time is preferably 5 minutes to 72 hours from the viewpoint of productivity.

  The epoxy resin composition of the present invention includes a conductive material, an anisotropic conductive material, an insulating material, a sealing material, a coating material, a coating composition, a prepreg, a heat, in addition to an adhesive and / or a bonding paste and a bonding film. It is useful as a conductive material.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Example 1]
(Synthesis of amine adduct particles (1))
Add 288 g of 2-methylimidazole to 824.2 g of 1-butanol and toluene mixed in 1/1 (mass ratio) in a 3000 ml three-necked separable flask equipped with a condenser, isostatic dropping funnel and stirring device. The mixture was heated to 80 ° C. in an oil bath with stirring to dissolve 2-methylimidazole. Next, a solution obtained by dissolving 946 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolyzed chlorine content 0.01% by mass) in 300 g of 1-butanol and toluene 1/1 (mass ratio) was added with an isobaric dropping funnel. And dropped over 90 minutes. After completion of dropping, the mixture was heated at 80 ° C for 5 hours. Then, it heated up to 180 degreeC and distilled the solvent off. The temperature was kept at 180 ° C., the pressure inside the apparatus was reduced until the pressure finally reached 10 mmHg or less, and the solvent was distilled off. After the pressure became 10 mmHg or less, the heated solvent was distilled off under reduced pressure for 2 hours to obtain a dark reddish brown viscous liquid. After the pressure was brought to normal pressure and the viscous liquid was brought to 100 ° C., 168.3 g of 2-methylimidazole was added and further stirred for 2 hours. The viscous liquid was cooled to room temperature to obtain a dark red-brown solid amine adduct 2. The amine adduct 2 was pulverized with a jet mill to obtain amine adduct particles (1) having an average particle size of 2.10 μm (2-methylimidazole content: 12% by mass). The average particle size of the amine adduct particles was measured three times using a laser diffraction particle size distribution analyzer (Mastersizer 2000: dry measurement unit Scirocco 2000) manufactured by Malvern, and the average value of 50% diameter (median diameter). Was the average particle size (hereinafter the same).
(Preparation of microcapsule type latent curing agent (1))
45.0 g of amine adduct particles (1) and 171.0 g of cyclohexane were added to a three-necked separable flask equipped with a condenser, a thermocouple, and a stirring device, heated to 40 ° C., and then 1.2 g of water was added. After stirring for 10 minutes, 3.0 g of 4,4′-diphenylmethane diisocyanate was added and reacted at 40 ° C. for 2 hours. Subsequently, it heated up at 50 degreeC and made it react for 6 hours. After completion of the reaction, the dispersion was filtered and washed with cyclohexane heated to 50 ° C. The obtained powder was dried under reduced pressure for 24 hours at a pressure of 10 mmHg or less, and the solvent was removed to obtain a microcapsule-type latent curing agent (1).
(Preparation of one-component epoxy resin composition (1))
Microcapsule type latent curing agent (1) 33 g is blended with bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolyzed chlorine content 0.01 mass%) 67 g to form a one-part epoxy resin composition (1) Got.

[Example 2]
(Synthesis of amine adduct particles (2))
Amine adduct particles (2) (average particle size: 2) were prepared in the same manner as the synthesis of amine adduct particles (1) except that 64.4 g of 4,4′-diaminodiphenylmethane was used instead of 168.3 g of 2-methylimidazole. .21 μm, 4,4′-diaminodiphenylmethane content: 5% by mass).
(Preparation of microcapsule type latent curing agent (2))
45.0 g of amine adduct particles (2) and 171.0 g of cyclohexane were added to a three-necked separable flask equipped with a condenser, a thermocouple, and a stirrer, heated to 40 ° C., and then 1.2 g of water was added. After stirring for 10 minutes, 3.0 g of polymeric MDI (Nippon Polyurethane Corporation: product name MR-200) was added and reacted at 40 ° C. for 2 hours. Subsequently, it heated up at 50 degreeC and made it react for 6 hours. After completion of the reaction, the dispersion was filtered and washed with cyclohexane heated to 50 ° C. The obtained powder was dried under reduced pressure for 24 hours at a pressure of 10 mmHg or less, and the solvent was removed to obtain a microcapsule-type latent curing agent (2).
(Preparation of one-part epoxy resin composition (2))
Microcapsule type latent curing agent (2) 33 g is mixed with 67 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolyzed chlorine content 0.01% by mass) to form a one-part epoxy resin composition (2) Got.

[Example 3]
(Preparation of one-part epoxy resin composition (3))
The one-component epoxy resin composition (2) prepared in the same manner as in Example 2 was stirred at 50 ° C. for 24 hours in a nitrogen atmosphere to obtain a one-component epoxy resin composition (3).

[Comparative Example 1]
(Synthesis of amine adduct particle (3))
In a 3000 ml three-necked separable flask equipped with a condenser, an isostatic dropping funnel, and a stirrer, 144.0 g of 2-methylimidazole was added to 412.1 g of a solution in which 1-butanol and toluene were mixed at a 1/1 (mass ratio). The mixture was heated to 80 ° C. in an oil bath with stirring to dissolve 2-methylimidazole. Next, a solution obtained by dissolving 473 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, amount of hydrolyzed chlorine 0.01% by mass) in 150 g of 1-butanol and toluene 1/1 (mass ratio) solution was added at a constant pressure dropping funnel. Was added dropwise over 90 minutes. After completion of dropping, the mixture was heated at 80 ° C. for 5 hours. Then, it heated up to 180 degreeC and distilled the solvent off. The temperature was kept at 180 ° C., the pressure inside the apparatus was reduced until the pressure finally reached 10 mmHg or less, and the solvent was distilled off. After the pressure became 10 mmHg or less, the heated solvent was distilled off under reduced pressure for 2 hours to obtain a dark reddish brown viscous liquid. After the pressure was brought to normal pressure and the viscous liquid was brought to 100 ° C., 617 g of 2-methylimidazole was added and further stirred for 2 hours. The viscous liquid was cooled to room temperature to obtain a dark reddish brown solid amine adduct 4. The amine adduct 4 was pulverized with a jet mill to obtain amine adduct particles (3) having an average particle size of 2.05 μm.
(Preparation of microcapsule type latent curing agent (3))
A microcapsule-type latent curing agent (3) was obtained in the same manner as in Example 1 except that the amine adduct particle (3) was used instead of the amine adduct particle (1).
(Preparation of one-part epoxy resin composition (4))
A one-part epoxy resin composition (4) is prepared in the same manner as in Example 1 except that the microcapsule type latent curing agent (3) is used instead of the microcapsule type latent curing agent (1). did.

[Comparative Example 2]
(Synthesis of amine adduct particles (4))
Add 288 g of 2-methylimidazole to 824.2 g of 1-butanol and toluene mixed in 1/1 (mass ratio) in a 3000 ml three-necked separable flask equipped with a condenser, isostatic dropping funnel and stirring device. The mixture was heated to 80 ° C. in an oil bath with stirring to dissolve 2-methylimidazole. Next, a solution obtained by dissolving 946 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolyzed chlorine content 0.01% by mass) in 300 g of 1-butanol and toluene 1/1 (mass ratio) was added with an isobaric dropping funnel. Used and dropped in 90 minutes. After completion of dropping, the mixture was heated at 80 ° C. for 5 hours. Then, it heated up to 180 degreeC and distilled the solvent off. The temperature was kept at 180 ° C., the pressure inside the apparatus was reduced until the pressure finally reached 10 mmHg or less, and the solvent was distilled off. After the pressure became 10 mmHg or less, the heated solvent was distilled off under reduced pressure for 2 hours to obtain a dark reddish brown viscous liquid. The viscous liquid was cooled to room temperature to obtain a dark reddish brown solid amine adduct 1. The amine adduct 1 was pulverized with a jet mill to obtain amine adduct particles (4) having an average particle size of 1.96 μm.
(Preparation of microcapsule type latent curing agent (4))
A microcapsule-type latent curing agent (4) was obtained in the same manner as in Example 2 except that the amine adduct particle (4) was used instead of the amine adduct particle (1).
(Preparation of one-part epoxy resin composition (5))
A one-part epoxy resin composition (5) was prepared in the same manner as in Example 1 except that the microcapsule type latent curing agent (4) was used instead of the microcapsule type latent curing agent (1). did.

[Comparative Example 3]
In a three-neck separable flask equipped with a condenser, a thermocouple, and a stirrer, 33 g of amine adduct particles (1) and 67 g of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, amount of hydrolyzed chlorine 0.01% by mass) And was heated to 40 ° C., and then 0.5 g of water was added. After stirring for 10 minutes, 4.0 g of 4,4′-diphenylmethane diisocyanate was added and heated at 40 ° C. for 2 hours. Next, when the temperature was raised to 50 ° C. and heated for 6 hours, the curing reaction proceeded in the flask, and a one-component epoxy resin composition could not be obtained.

  Examples 1 to 3 and Comparative Examples 1 to 3 Composition of one-part epoxy resin composition, core composition, type of encapsulating raw material, presence or absence of heat treatment of microcapsule type latent curing agent in epoxy resin Shown in Tables 1 and 2. In Tables 1 and 2, “BisA” represents bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolyzed chlorine content 0.01 mass%), “MDI” represents 4,4′-diphenylmethane diisocyanate, “2MZ” means 2-methylimidazole, “PMDI” means polymeric MDI, and “DDM” means 4,4′-diaminodiphenylmethane.

  Moreover, about the one-component epoxy resin composition of Examples 1-3 and the comparative examples 1 and 2, hardening characteristics and storage stability were evaluated with the following method. The results are shown in Tables 1 and 2. In Comparative Example 3, since the one-component epoxy resin composition was not obtained as described above, the curing characteristics and the storage stability could not be evaluated.

[Evaluation of curing characteristics]
DSC measurement was performed on the one-component epoxy resin composition under the following conditions to evaluate the curing characteristics.
Using a Perkin-Elmer DSC7 differential calorimeter, the heating rate was 10 ° C./min, the measurement temperature range was 30 ° C. to 300 ° C., and the nitrogen atmosphere was used. When the obtained peak top temperature was less than 115 ° C, it was A, when it was 115 ° C or more and less than 120 ° C, it was B, and when it was 120 ° C or more, C.

[Evaluation of storage stability]
A sample obtained by adding the same weight of bisphenol A type epoxy resin (epoxy equivalent 173 g / eq, hydrolyzed chlorine content 0.01% by mass) to the one-part epoxy resin composition was stored in a constant temperature bath at 40 ° C. for 30 days. . For each of the sample before storage and the sample after storage for 30 days, the viscosity at 25 ° C. was measured using an E-type viscometer, and the storage stability was evaluated based on the rate of increase in viscosity after 30 days. When measuring viscosity, use a cone at 3 ° C, measure at 10 rpm for 3-40 Pa · s, 2.5 rpm for 40-200 Pa · s, and 0.5 rpm for 200-1000 Pa · s. did. If the rate of increase in viscosity after 30 days is 50% or less, it is A, if it is less than 100%, it is B, and if it is 100% or more, it is C.

Claims (8)

A core containing 60 to 99.99% by mass of an amine adduct and 0.01 to 40% by mass of at least one nitrogen-containing compound selected from a compound having a primary amino group and / or a secondary amino group and an imidazole compound; ,
A capsule that is provided so as to cover the core, and is formed by reacting the core with isocyanate and water and / or a compound having an active hydrogen group;
A microcapsule type latent curing agent for epoxy resin.   The microcapsule-type latent curing agent for epoxy resins according to claim 1, wherein the melting point of the nitrogen-containing compound is 40 ° C to 200 ° C.   The microcapsule type latent curing agent for epoxy resins according to claim 1 or 2, comprising an aromatic amine having a primary and / or secondary amino group as the nitrogen-containing compound.   The microcapsule-type latent curing agent (F) for epoxy resins according to claim 3, wherein the aromatic amine is at least one selected from diaminodiphenylmethane and metaphenylenediamine. In a dispersion medium having a boiling point of 150 ° C. or less at 1 atm and a viscosity of 1000 mPa · s or less at 25 ° C.,
A core containing 60 to 99.99% by mass of an amine adduct and 0.01 to 40% by mass of at least one nitrogen-containing compound selected from a compound having a primary amino group and / or a secondary amino group and an imidazole compound; ,
Isocyanate,
A process for forming a capsule covering the core by reacting with a compound having water and / or an active hydrogen group, and removing a dispersion medium to obtain a microcapsule type latent curing agent for an epoxy resin. A method for producing a capsule-type latent curing agent.   The one-pack type epoxy resin composition containing the microcapsule type | mold latent hardening | curing agent of any one of Claims 1-4, and an epoxy resin.   The one-component epoxy resin composition according to claim 6, wherein the microcapsule-type latent curing agent is subjected to a heating treatment at a temperature equal to or lower than a melting point or a softening point of the core component in the epoxy resin.   The epoxy resin hardened | cured material obtained by heating the one-component epoxy resin composition of Claim 6 or 7.