JP6628089B2 - Curable composition and adhesive - Google Patents

Description

  The present invention relates to a curable composition having high toughness in a cured product and excellent adhesion to a metal substrate, and a cured product, an adhesive, and a structure thereof.

  In recent years, lightweight materials such as aluminum, magnesium, and plastic have been adopted as automobile body materials from the viewpoint of energy saving, and adhesives have been increasingly used in assembling instead of welding. The characteristics of automotive adhesives are that they are used for bonding between different materials and that the temperature of the operating environment changes very sharply.Currently, epoxy resin adhesives with excellent heat resistance and mechanical properties are mainly used. ing. However, conventional epoxy resin-based adhesives have insufficient flexibility and toughness in the cured product and cannot follow the thermal deformation of the member, so that there is a problem that distortion and peeling are likely to occur in high-temperature and low-temperature environments. In particular, when different materials such as a metal material and a non-metal material are bonded, the difference in thermal expansion coefficient between the two materials is large, and the problems of distortion and peeling have been remarkable.

  Conventionally known epoxy resin-based adhesives include, for example, an adhesive containing a bisphenol A type epoxy resin, a urethane-modified epoxy resin, a rubber-modified epoxy resin, and a monofunctional aliphatic epoxy resin as an epoxy resin component (Patent There is known an adhesive (see Patent Document 2) using a bisphenol A type epoxy resin, a urethane-modified epoxy resin, or a rubber-modified epoxy resin as an epoxy resin component, and further adding various rubber particles. All of these adhesives impart toughness to the cured product by using the urethane-modified epoxy resin or rubber-modified epoxy resin as an epoxy resin component, but do not satisfy the current market demand level and are higher. An epoxy resin-based adhesive having both toughness and adhesiveness has been demanded.

JP 2009-108278 A JP 2010-185034 A

  Accordingly, an object of the present invention is to provide a curable composition having high toughness in a cured product and excellent adhesion to a metal substrate, a cured product thereof, and an adhesive.

  The present inventors have conducted intensive studies to solve the above problems, and as a result, in a curable composition containing an epoxy resin and a curing agent, as the epoxy resin, a polyester-modified epoxy resin and a polyglycidyl ether of an aliphatic hydrocarbon. It has been found that the combination of (1) and (2) significantly improves the toughness of the cured product and also has excellent adhesion to the metal substrate, and has completed the present invention.

  That is, the present invention comprises an epoxy resin (A) and a curing agent or a curing accelerator (B), wherein the epoxy resin (A) is a polyester-modified epoxy resin (A1) and a polyglycidyl ether of an aliphatic hydrocarbon ( And A2) as an essential component.

  The present invention further relates to a cured product obtained by curing the curable composition.

  The present invention further relates to an adhesive comprising the curable composition.

  The present invention further relates to a structure using the adhesive.

  ADVANTAGE OF THE INVENTION According to this invention, the toughness in a hardened | cured material is high, and the curable composition excellent in the adhesiveness with respect to a metal base material, its hardened | cured material, an adhesive, and the structure using the same can be provided.

FIG. 1 is a GPC chart of the polyester-modified epoxy resin (A1-1) obtained in Production Example 1. FIG. 2 is a GPC chart of the polyester-modified epoxy resin (A1-2) obtained in Production Example 2.

Hereinafter, the present invention will be described in detail.
The curable composition of the present invention contains an epoxy resin (A) and a curing agent or a curing accelerator (B), wherein the epoxy resin (A) is a polyester-modified epoxy resin (A1) and an aliphatic hydrocarbon polyglycidyl. And ether (A2) as an essential component.

  The specific structure of the polyester-modified epoxy resin (A1) is not particularly limited as long as it has a polyester chain structure and an epoxy group in the resin structure. Among them, a bifunctional epoxy resin having two epoxy groups in one molecule is preferable because of its excellent toughness in the cured product. Further, as a cured product having particularly high toughness, the following general formula (1)

［式中Ｒ^１は水素原子又はポリエステル構造部位であり、Ｘはそれぞれ独立に下記一般式（２−１）〜（２−８）

[Wherein R ¹ is a hydrogen atom or a polyester structure site, and Xs are each independently the following general formulas (2-1) to (2-8)

（式中、Ｒ^２はそれぞれ独立に水素原子、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、Ｒ^３はそれぞれ独立に炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、ｎは０又は１以上の整数である。）
の何れかで表される構造部位である。］
で表される樹脂構造を有し、樹脂中に存在する前記Ｒ^１の少なくとも一つはポリエステル構造部位であるものが挙げられる。

(Wherein, R ² is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, and R ³ is each independently a group having 1 to 4 carbon atoms. Is an alkyl group or an alkoxy group having 1 to 4 carbon atoms, and n is 0 or an integer of 1 or more.)
Is a structural part represented by ]
Wherein at least one of the R ¹ present in the resin is a polyester structure site.

  X in the general formula (1) is a structural part represented by any of the general formulas (2-1) to (2-8). A plurality of Xs present in the resin may be the same structural part or different structural parts. Among them, a structural part represented by the general formula (2-1) or (2-2) is preferable because the polyester-modified epoxy resin (A1) having high toughness in a cured product is obtained.

R ¹ in the general formula (1) is a hydrogen atom or a hydrogen atom or a polyester structure site, and at least one of the R ¹ present in the resin is the polyester structure site. Among them, the content of the polyester structural site in the resin is preferably in the range of 25 to 45% by mass because the polyester-modified epoxy resin (A1) having high toughness in the cured product is obtained.

  Further, the epoxy group equivalent of the polyester-modified epoxy resin (A1) is preferably in the range of 400 to 1200 g / equivalent, and more preferably in the range of 500 to 1000 g / equivalent, because the toughness of the cured product is excellent. preferable.

  The method for producing the polyester-modified epoxy resin (A1) is not particularly limited. When the polyester-modified epoxy resin (A1) is represented by the general formula (1), for example, the following general formula (3)

［式中Ｘはそれぞれ独立に下記一般式（２−１）〜（２−８）

[Wherein X is independently the following general formulas (2-1) to (2-8)

（式中、Ｒ^２はそれぞれ独立に水素原子、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、Ｒ^３はそれぞれ独立に炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、ｎは０又は１以上の整数である。）
の何れかで表される構造部位である。］
で表される樹脂構造を有する水酸基含有エポキシ樹脂（ｃ）とラクトン化合物（ｄ）とを反応させる方法が挙げられる。

(Wherein, R ² is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, and R ³ is each independently a group having 1 to 4 carbon atoms. Is an alkyl group or an alkoxy group having 1 to 4 carbon atoms, and n is 0 or an integer of 1 or more.)
Is a structural part represented by ]
And a method of reacting a hydroxyl group-containing epoxy resin (c) having a resin structure represented by the following formula with a lactone compound (d).

The hydroxyl group-containing epoxy resin (c) is prepared, for example, by reacting bisphenol or biphenol type compound (c1) with these diglycidyl ether compounds (c2) (method 1), or bisphenol or bisphenol type compound (c1). And epihalohydrin (method 2). Above all, method 1 is preferable because the reaction is easily controlled and the epoxy equivalent of the obtained ester-modified epoxy resin (A1) is easily controlled to the preferable value.

  Regarding the method 1, the reaction ratio between the bisphenol or biphenol type compound (c1) and the diglycidyl ether compound (c2) is such that the mass ratio of both ((c1) / (c2)) is 10/90 to 30 /. It is preferably in the range of 70. The reaction temperature is preferably about 120 to 160 ° C., and a reaction catalyst such as tetramethylammonium chloride may be used.

  The epoxy group equivalent of the hydroxyl group-containing epoxy resin (c) is in the range of 300 to 600 g / equivalent because it is easy to adjust the epoxy group equivalent of the obtained polyester-modified epoxy resin (A1) to the preferred range. Preferably, there is.

  The lactone compound (d) is not particularly limited as long as it has a cyclic ester structure. For example, β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, 7-hydroxyheptanoic lactone, 4- to 10-membered lactones such as 8-hydroxyoctanoic acid lactone and 9-hydroxynonanoic acid lactone. Among them, ε-caprolactone is preferable because it becomes a polyester-modified epoxy resin (A1) having high toughness in a cured product.

  The reaction between the hydroxyl group-containing epoxy resin (c) and the lactone compound (d) may be carried out, for example, in the presence of a suitable reaction catalyst at a temperature of about 100 to 130 ° C. The mass ratio [(c) / (d)] of both is preferably a ratio in the range of 55/45 to 75/25, since the polyester-modified epoxy resin (A1) has high toughness in the cured product. .

  The specific structure of the aliphatic hydrocarbon polyglycidyl ether (A2) is not particularly limited as long as it has an aliphatic hydrocarbon group as a basic skeleton and has an epoxy group. Among them, a bifunctional compound having two epoxy groups in one molecule is preferable because of its excellent toughness in the cured product. Specifically, the following structural formula (4)

（Ｙは炭素原子数４〜２０の脂肪族炭化水素基である。）
で表される分子構造を有するものが好ましい。

(Y is an aliphatic hydrocarbon group having 4 to 20 carbon atoms.)
Those having a molecular structure represented by

  As the polyglycidyl ether (A2) of the aliphatic hydrocarbon, one type may be used alone, or two or more types may be used in combination. Further, Y in the general formula (3) is preferably a linear alkylene group, since the polyglycidyl ether (A2) of an aliphatic hydrocarbon having excellent adhesion to a metal substrate is obtained. More preferably, it is a linear alkylene group having the number of 4 to 10.

  In the present invention, as the epoxy resin (A), other epoxy resins may be used in addition to the polyester-modified epoxy resin (A1) and the polyglycidyl ether of the aliphatic hydrocarbon (A2). Other epoxy resins include, for example, urethane-modified epoxy resin (A3), rubber-modified epoxy resin (A4), bisphenol type epoxy resin, phenol novolak type, naphthol novolak type, cresol novolak type, phenol-cresol co-condensed novolak type and the like. Novolak-type epoxy resins, triphenylmethane-type epoxy resins, and the like.

  Above all, it is preferable to use a urethane-modified epoxy resin (A3) or a rubber-modified epoxy resin (A4), since a cured product having excellent toughness and excellent adhesion to a metal substrate is obtained.

  Since the content of the polyester-modified epoxy resin (A1) in the epoxy resin (A) is a curable composition having an excellent balance between toughness in a cured product and adhesion to a metal substrate, the epoxy resin (A) Is preferably the polyester-modified epoxy resin (A1), and more preferably 40 to 80% by mass is the polyester-modified epoxy resin (A1).

  The content of the aliphatic hydrocarbon polyglycidyl ether (A2) in the epoxy resin (A) is a curable composition having an excellent balance between toughness in a cured product and adhesion to a metal substrate. Preferably, 5 to 40% by mass of the resin (A) is the polyglycidyl ether of the aliphatic hydrocarbon (A2), and 10 to 30% by mass is the polyglycidyl ether of the aliphatic hydrocarbon (A2). Is more preferred.

  When the epoxy resin (A) contains the urethane-modified epoxy resin (A3), the content thereof is a curable composition having an excellent balance between toughness in a cured product and adhesion to a metal substrate. Preferably, 5 to 30% by mass of the epoxy resin (A) is the urethane-modified epoxy resin (A3), and more preferably, 5 to 20% by mass is the urethane-modified epoxy resin (A3).

  When the epoxy resin (A) contains the rubber-modified epoxy resin (A4), the content is a curable composition having an excellent balance between toughness in a cured product and adhesion to a metal substrate. Preferably, 5 to 30% by mass of the epoxy resin (A) is the rubber-modified epoxy resin (A4), and more preferably, 5 to 20% by mass is the rubber-modified epoxy resin (A4).

  The specific structure of the urethane-modified epoxy resin (A3) is not particularly limited as long as the resin structure has a urethane structure and an epoxy group. Among them, those obtained by reacting a hydroxyl group-containing epoxy resin (e) having a resin structure represented by the general formula (3) with an isocyanate group-containing urethane resin (f), as those having particularly high toughness in a cured product. Is mentioned.

  Since the hydroxyl group-containing epoxy resin (e) becomes a urethane-modified epoxy resin (A2) having high toughness in a cured product, X in the structural formula (3) is represented by the structural formulas (2-1) to (2-). Preferred is a structural site represented by any of 8). The hydroxyl group-containing epoxy resin (e) is obtained by the same method as that for the hydroxyl group-containing epoxy resin (c), and its epoxy equivalent is preferably in the range of 120 to 450 g / equivalent.

  The isocyanate group-containing urethane resin (f) is not particularly limited as long as it has an isocyanate group and a urethane binding site in the molecular structure. Specifically, the polyisocyanate compound (f1) and the polyol compound (f2) are mixed under the condition that the number of isocyanate groups contained in the polyisocyanate compound (f1) is excessive with respect to the number of hydroxyl groups contained in the polyol compound (f2). What is obtained by making it react is mentioned.

  Examples of the polyisocyanate compound (f1) include various diisocyanate monomers and modified forms thereof such as a nurate modified form, an adduct modified form and a biuret modified form. One type may be used alone, or two or more types may be used in combination. May be.

  Examples of the diisocyanate monomer include butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, and m-tetramethylxylylene. Aliphatic diisocyanate such as diisocyanate; alicyclic ring such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate Formula diisocyanate: 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-bi (Paraphenyl isocyanate) Aromatic diisocyanates such as propane, 4,4'-dibenzyl diisocyanate, dialkyl diphenyl methane diisocyanate, tetraalkyl diphenyl methane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and tolylene diisocyanate. Can be

  Among the polyisocyanate compounds (f1), the diisocyanate monomer is preferable, and an alicyclic diisocyanate or an aromatic diisocyanate is more preferable because the urethane-modified epoxy resin (A2) having high toughness in a cured product is obtained.

  The polyol compound (f2) is not particularly limited as long as it is a compound having two or more hydroxyl groups in a molecular structure, and any of various diol compounds, triol compounds, and tetrafunctional or higher polyol compounds can be used. Among them, a diol compound is preferable because it becomes a urethane-modified epoxy resin having excellent flexibility and toughness in a cured product.

  Examples of the diol compound include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, and 1,5. Aliphatic diols such as -pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol and 1,6-hexanediol; hydroquinone, 2-methylhydroquinone, 1,4-benzenedimethanol, 3,3 ′ -Biphenyldiol, 4,4'-biphenyldiol, biphenyl-3,3'-dimethanol, biphenyl-4,4'-dimethanol, bisphenol A, bisphenol B, bisphenol F, bisphenol S, 1,4-naphthalenediol , 1,5-naphthalene diol, 2 Aromatic ring-containing diols such as 6-naphthalene diol and naphthalene-2,6-dimethanol; various types such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether and allyl glycidyl ether Ring-opening polymerization of a cyclic ether compound, or a polyether-modified diol obtained by polymerization of the aliphatic or aromatic ring-containing diol with these cyclic ether compounds; ring-opening polymerization of a lactone compound such as ε-caprolactone; -Modified diol obtained by polymerization of an aromatic or aromatic ring-containing diol with a lactone compound: the aliphatic or aromatic ring-containing polyol, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli Polyester diols obtained by reacting an aliphatic dicarboxylic acid such as an acid, phthalic acid, phthalic anhydride, terephthalic acid, isophthalic acid, an aromatic dicarboxylic acid such as orthophthalic acid, or an anhydride thereof; Polycarbonate diol obtained by reacting an aromatic ring-containing polyol with a carbonylating agent such as phosgene, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, and the like. These may be used alone or in combination of two or more.

  Among them, a polyether-modified diol is preferable because it becomes a urethane-modified epoxy resin (A3) having high toughness in a cured product. Moreover, it is preferable that the weight average molecular weight (Mw) is in the range of 1,000 to 4,000.

In the present invention, the weight average molecular weight (Mw) is a value measured by gel permeation chromatography (GPC) under the following conditions.

Measurement device: Tosoh Corporation HLC-8220GPC
Column: TSK-GUARDCOLUMN SuperHZ-L manufactured by Tosoh Corporation
+ TSK-GEL SuperHZM-M x 4 manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Data processing: Multi-station GPC-8020 model II manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40 ° C
Solvent Tetrahydrofuran
Flow rate: 0.35 ml / min Standard: Monodisperse polystyrene sample: 0.2% by mass of resin in solid tetrahydrofuran solution filtered through a microfilter (100 μl)

  The method for producing the isocyanate group-containing urethane resin (f) by reacting the polyisocyanate compound (f1) with the polyol compound (f2) includes, for example, an isocyanate group contained in the polyisocyanate compound (f2) and a polyol The molar ratio [(NCO) / (OH)] with respect to the hydroxyl group of the compound (f2) is in the range of 1.5 / 1 to 4.5 / 1, and both are used. Among them, a method using a known and commonly used urethanization catalyst may be mentioned as needed. The isocyanate content of the obtained isocyanate group-containing urethane resin (f) is preferably in the range of 2 to 4% by mass.

  The method of reacting the hydroxyl-containing epoxy resin (e) with the isocyanate-containing urethane resin (f) to obtain a urethane-modified epoxy resin (A3) may be performed, for example, within a temperature range of 20 to 120 ° C. And a method in which a known and commonly used urethane-forming catalyst is used and the mass ratio [(e) / (f)] of both is reacted at a ratio of 85/15 to 55/45.

  The epoxy group equivalent of the urethane-modified epoxy resin (A3) is preferably in the range of 200 to 600 g / equivalent because the toughness of the cured product is excellent.

  The specific structure of the rubber-modified epoxy resin (A4) is not particularly limited as long as the resin structure has a rubber chain structure and an epoxy group. Specific examples include those obtained by reacting a bifunctional epoxy resin with a carboxyl group-terminated butadiene rubber having a copolymer of butadiene and acrylonitrile as a main skeleton and having carboxyl groups at both ends.

  Although the specific structure of the bifunctional epoxy resin is not particularly limited, it is preferably a bisphenol-type epoxy resin because it is a rubber-modified epoxy resin (A4) having high toughness and high adhesion to a metal substrate. More preferably, it is an A-type epoxy resin.

  The epoxy group equivalent of the rubber-modified epoxy resin (A4) is preferably in the range of 200 to 600 g / equivalent because the rubber-modified epoxy resin (A4) has high toughness and high adhesion to a metal substrate. .

  The curable composition of the present invention contains the epoxy resin (A) and a curing agent or a curing accelerator (B).

  As the curing agent or the curing accelerator (B), those generally used for curing the epoxy resin (A) can be widely used, one kind may be used alone, or two or more kinds may be used in combination. You may. Specific examples of the curing agent or curing accelerator (B) include polyamine compounds, amide compounds, acid anhydrides, phenolic hydroxyl group-containing resins, phosphorus compounds, imidazole compounds, imidazoline compounds, urea compounds, and organic acid metals. Salts, Lewis acids, amine complex salts and the like.

  Examples of the polyamine compound include trimethylenediamine, ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, pentamethyldiethylenetriamine, triethylenediamine, dipropylenediamine, N, N, N ′, N′-tetramethyl. Propylene diamine, tetramethylene diamine, pentane diamine, hexamethylene diamine, trimethyl hexamethylene diamine, N, N, N ', N'-tetramethyl hexamethylene diamine, N, N-dimethylcyclohexylamine, diethylene triamine, triethylene tetramine, tetraethylene Ethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, 1,4-diazabicyclo (2,2,2) octane (triethylene Amine), polyoxyethylene diamine, polyoxypropylene diamine, bis (2-dimethylaminoethyl) ether, dimethylaminoethoxy ethoxyethanol, triethanolamine, aliphatic amine compounds such as dimethylamino hexanol;

  Piperidine, piperazine, menthanediamine, isophoronediamine, methylmorpholine, ethylmorpholine, N, N ', N "-tris (dimethylaminopropyl) hexahydro-s-triazine, 3,9-bis (3-aminopropyl) -2, 4,8,10-tetraoxyspiro (5,5) undecane adduct, N-aminoethylpiperazine, trimethylaminoethylpiperazine, bis (4-aminocyclohexyl) methane, N, N'-dimethylpiperazine, 1,8-diazabicyclo Alicyclic and heterocyclic amine compounds such as-[5.4.0] -undecene (DBU);

  aromatic amines such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, benzylmethylamine, dimethylbenzylamine, m-xylenediamine, pyridine, picoline and α-methylbenzylmethylamine Compound;

  Epoxy compound added polyamine, Michael added polyamine, Mannich added polyamine, thiourea added polyamine, ketone-blocked polyamine, dicyandiamide, guanidine, organic acid hydrazide, diaminomaleonitrile, amine imide, boron trifluoride-piperidine complex, boron trifluoride-mono Modified amine compounds such as an ethylamine complex are exemplified.

  Examples of the amide compound include dicyandiamide and polyamidoamine. The polyamidoamine is, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, aliphatic dicarboxylic acids such as azelaic acid, fatty acids, carboxylic acid compounds such as dimer acid, and aliphatic polyamines and polyoxyalkylenes Those obtained by reacting a polyamine having a chain and the like can be mentioned.

  Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydro. And phthalic anhydride.

  Examples of the phenolic hydroxyl group-containing resin include phenol novolak resin, cresol novolak resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin (Xyloc resin), naphthol aralkyl resin, Trimethylolmethane resin, tetraphenylolethane resin, naphthol novolak resin, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin (polyphenol compound with phenol nucleus linked by bismethylene group) , Biphenyl-modified naphthol resin (a polyvalent naphthol compound having a phenol nucleus linked by a bismethylene group), aminotriazine-modified phenol resin (melamine, benzol Polyhydric phenol compounds such as a polyphenol compound in which a phenol nucleus is linked with an anamine or the like and an aromatic ring-modified novolak resin containing an alkoxy group (a polyphenol compound in which a phenol nucleus and an alkoxy group-containing aromatic ring are linked in formaldehyde) are used. No.

  Examples of the phosphorus compound include: alkyl phosphines such as ethyl phosphine and butyl phosphine; first phosphines such as phenyl phosphine; dialkyl phosphines such as dimethyl phosphine and dipropyl phosphine; second phosphines such as diphenyl phosphine and methyl ethyl phosphine; trimethyl phosphine And tertiary phosphines such as triethylphosphine and triphenylphosphine.

  Examples of the imidazole compound include imidazole, 1-methylimidazole, 2-methylimidazole, 3-methylimidazole, 4-methylimidazole, 5-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 3-ethylimidazole, -Ethylimidazole, 5-ethylimidazole, 1-n-propylimidazole, 2-n-propylimidazole, 1-isopropylimidazole, 2-isopropylimidazole, 1-n-butylimidazole, 2-n-butylimidazole, 1-isobutyl Imidazole, 2-isobutylimidazole, 2-undecyl-1H-imidazole, 2-heptadecyl-1H-imidazole, 1,2-dimethylimidazole, 1,3-dimethylimidazole, 2,4-dimethyl Luimidazole, 2-ethyl-4-methylimidazole, 1-phenylimidazole, 2-phenyl-1H-imidazole, 4-methyl-2-phenyl-1H-imidazole, 2-phenyl-4-methylimidazole, 1-benzyl- 2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl- 2-phenylimidazole, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, - include cyanoethyl-2-phenyl-4,5-di (2-cyanoethoxy) methylimidazole, 1-dodecyl-2-methyl-3-benzyl-imidazolium chloride, 1-benzyl-2-phenylimidazole hydrochloride etc.

  Examples of the imidazoline compound include 2-methylimidazoline and 2-phenylimidazoline.

  Examples of the urea compound include p-chlorophenyl-N, N-dimethylurea, 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -N, N-dimethylurea, and N- (3 -Chloro-4-methylphenyl) -N ', N'-dimethylurea and the like.

  In the present invention, the compounding amount of the epoxy resin component and the curing agent or the curing accelerator is such that when a curing agent having a functional group capable of reacting with an epoxy group is used, the curing is performed with respect to 1 mol of the epoxy group in the epoxy resin component. It is preferable to mix the functional groups in the agent at a ratio of 0.3 to 1.1 mol. When a curing accelerator is used, it is preferable to mix the curing accelerator in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin component.

  The curable composition of the present invention further comprises an organic solvent, an ultraviolet absorber, an antioxidant, a silicon-based additive, a fluorine-based additive, a flame retardant, a plasticizer, a silane coupling agent, organic fine particles, an inorganic filler, It may contain a rheology control agent, a defoaming agent, an anti-fogging agent, a coloring agent and the like. These various components may be added in optional amounts depending on the desired performance.

  The organic fine particles include, for example, polymethyl methacrylate fine particles, polycarbonate fine particles, polystyrene fine particles, polyacrylstyrene fine particles, silicone fine particles, glass fine particles, acrylic fine particles, benzoguanamine-based resin fine particles, melamine-based resin fine particles, polyolefin-based resin fine particles, and polyester-based fine particles. Resin fine particles, polyamide resin fine particles, polyimide resin fine particles, polyfluoroethylene resin fine particles, polyethylene resin fine particles, and the like can be given. These may be used alone or in combination of two or more.

  The inorganic filler, for example, silica, alumina, zirconia, titania, barium titanate, antimony trioxide, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, clay, pyrophyllite, bentonite, sericite, zeolite, mica, Examples include mica, talc, attapulgite, and ferrite. These may be used alone or in combination of two or more. These inorganic fillers preferably have an average particle size in the range of 0.1 to 100 μm.

  The curable composition of the present invention is obtained by mixing the epoxy resin (A), the curing agent or the curing accelerator (B), and the various optional components with a planetary mixer, a pot mill, a ball mill, a bead mill, a roll mill, a homogenizer, and a super mill. , A homodisper, a universal mixer, a Banbury mixer, a kneader, or the like, and uniformly mixed.

  The use of the curable composition of the present invention is not particularly limited, and the curable composition can be used for various uses such as a paint, a coating agent, a molding material, an insulating material, a sealant, a sealant, and a fiber binding agent. Among them, the cured product can be suitably used as an adhesive for structural members in the fields of automobiles, trains, civil engineering, electronics, aircraft, and the space industry, taking advantage of its characteristics of excellent toughness and excellent adhesion to metal substrates. The adhesive of the present invention can maintain a high adhesiveness without being affected by a change in the temperature environment, for example, even when used for bonding different materials such as between a metal and a nonmetal. hard. In addition, the adhesive of the present invention can be used as an adhesive for general office work, medical use, carbon fiber, electronic materials, and the like in addition to structural member applications. Adhesives for interlayer of multi-layer substrates such as substrates, adhesives for bonding optical components, adhesives for bonding optical discs, adhesives for mounting printed wiring boards, die bonding adhesives, adhesives for semiconductors such as underfills, BGA reinforcement unders An adhesive for mounting such as a fill, an anisotropic conductive film, and an anisotropic conductive paste may be used.

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

Production Example 1 Production of Polyester-Modified Epoxy Resin (A1-1) In a flask equipped with a thermometer, a stirrer, and a reflux condenser, a bisphenol A type epoxy resin ("EPICLON 850" manufactured by DIC Corporation, epoxy equivalent: 188 g / equivalent) 48 parts by mass, 12 parts by mass of bisphenol A, and 0.002 parts by mass of tetramethylammonium chloride as a catalyst are charged, and the mixture is heated to 140 ° C. and stirred, and reacted until the epoxy equivalent becomes 400 g / equivalent. Resin (c-1) was obtained. Then, the temperature in the reaction system was lowered to 110 ° C., and 40 parts by mass of ε-caprolactone and 0.05 parts by mass of dioctyltin catalyst (“Neostan U-830” manufactured by Nitto Kasei Co., Ltd.) were added. The reaction was performed until the nonvolatile content became 99% by mass or more to obtain a polyester-modified epoxy resin (A1-1), and the obtained polyester-modified epoxy resin (A1-1) had an epoxy equivalent of 670 g / equivalent.

Production Example 2 Production of Polyester-Modified Epoxy Resin (A1-2) In a flask equipped with a thermometer, a stirrer, and a reflux condenser, a bisphenol F type epoxy resin (“EPICLON 830” manufactured by DIC Corporation, epoxy equivalent 170 g / equivalent) 49 parts by mass, 11 parts by mass of bisphenol F, and 0.002 parts by mass of tetramethylammonium chloride as a catalyst are charged, and the mixture is heated to 140 ° C. and stirred until the epoxy equivalent becomes 340 g / equivalent. Resin (c-2) was obtained. Then, the temperature in the reaction system was lowered to 110 ° C., and 40 parts by mass of ε-caprolactone and 0.05 parts by mass of dioctyltin catalyst (“Neostan U-830” manufactured by Nitto Kasei Co., Ltd.) were added. The reaction was performed until the nonvolatile content became 99% by mass or more to obtain a polyester-modified epoxy resin (A1-2) .The obtained polyester-modified epoxy resin (A1-2) had an epoxy equivalent of 590 g / equivalent.

Production Example 3 Production of Polyester-Modified Epoxy Resin (A1-3) In a flask equipped with a thermometer, a stirrer, and a reflux condenser, a bisphenol A-type epoxy resin ("EPICLON 850" manufactured by DIC Corporation, epoxy equivalent: 188 g / equivalent) 46.5 parts by mass, 13.5 parts by mass of bisphenol A, and 0.002 parts by mass of tetramethylammonium chloride as a catalyst were charged, and reacted until the epoxy equivalent reached 470 g / equivalent while heating and stirring to 140 ° C. Thus, a hydroxyl group-containing epoxy resin (c-3) was obtained. Then, the temperature in the reaction system was lowered to 110 ° C., and 40 parts by mass of ε-caprolactone and 0.05 parts by mass of dioctyltin catalyst (“Neostan U-830” manufactured by Nitto Kasei Co., Ltd.) were added. The reaction was performed until the nonvolatile content became 99% by mass or more to obtain a polyester-modified epoxy resin (A1-3) The epoxy equivalent of the obtained polyester-modified epoxy resin (A1-3) was 800 g / equivalent.

Production Example 4 Production of Urethane-Modified Epoxy Resin (A3-1) In a flask equipped with a thermometer, a stirrer, and a reflux condenser, polypropylene glycol (“Actocol D-3000” manufactured by Mitsui Chemicals, Inc.) with a hydroxyl value of 37.5 mgKOH / g) 26.1 parts by mass, 3.9 parts by mass of isophorone diisocyanate, and 0.002 parts by mass of dioctyltin catalyst ("Neostan U-830" manufactured by Nitto Kasei Co., Ltd.) as a catalyst. The reaction was continued until the isocyanate group content reached 2.3% by mass, and then 55.9 parts by mass of a bisphenol A type epoxy resin ("EPICLON 850" manufactured by DIC Corporation, epoxy equivalent: 188 g / equivalent), and bisphenol A type epoxy Resin (DIC Corporation "EPICLON 1050" epoxy equivalent 470g / equivalent) Were charged 14.1 parts by weight, and heated to 80 ° C., reacted until the isocyanate content is 0 mass% to obtain a polyurethane-modified epoxy resin (A3-1).

Other components used in Examples: Polyglycidyl ether of aliphatic hydrocarbon (A2-1): 1,6-hexanediol diglycidyl ether / rubber-modified epoxy resin (A4-1): "EPICLON TSR" manufactured by DIC Corporation -601 "Epoxy group equivalent 475g / equivalent rubber-modified epoxy resin (A4-2): DIC Corporation" EPICLON TSR-930 "Epoxy group equivalent 190g / equivalent. Other epoxy resin (1): Bisphenol A type epoxy resin ("EPICLON 850" epoxy equivalent, 188 g / equivalent, manufactured by DIC Corporation)
-Other epoxy resin (2): Glycidyl ether of neodecanoic acid ("Kajura E-10P" manufactured by Hexion Specialty Chemicals Japan Co., Ltd.)
-Other epoxy resin (3): bisphenol A bis (polyoxyethylene glycol glycidyl ether) ether (Shin Nihon Rika "Likaresin BEO-60E" epoxy group equivalent 351 g / equivalent)
Curing agent / curing accelerator (B-1): dicyandiamide Curing agent / curing accelerator (B-2): 3- (3,4-dicyclophenyl) -1,1-dimethylurea (DCMU)
・ Silica: RY-200S manufactured by Nippon Aerosil Co., Ltd.
・ Acrylic fine particles: “ZEFIAC F351” manufactured by Aika Kogyo Co., Ltd.

Examples 1 to 6, Comparative Examples 1 and 2
A curable composition was manufactured in the following manner, and various evaluation tests were performed. Table 1 shows the results.

◆ Production of curable composition Each component was blended at the ratios shown in Tables 1 and 2, and dispersed with a disper to obtain a curable composition.

◆ Evaluation of Toughness The curable composition obtained above was poured into a mold having a thickness of 2 mm and cured at 170 ° C. for 30 minutes. A No. 1 dumbbell-type sample was cut out from the cured product, and a tensile test was performed using “AUTOGRAPH AG-IS 1 kN” manufactured by Shimadzu Corporation to evaluate elongation (%).

◆ Evaluation of adhesiveness to metal substrate Using zinc phosphate treated steel plate SPCC-SB (200 × 25 × 0.5 mm) manufactured by TP Giken Co., Ltd. as a substrate, first set the cured coating film thickness to 200 μm. The obtained curable composition was applied and cured at 170 ° C. for 30 minutes. According to JIS K6854-S, a T-shaped peel test of the cured coating film was performed using "AUTOGRAPH AG-IS 10 kN" manufactured by Shimadzu Corporation, and evaluated by average peel strength (N / mm).

Claims (7)

The epoxy resin (A) contains an epoxy resin (A) and a curing agent or a curing accelerator (B), and the epoxy resin (A) has the following general formula (1)

[Wherein R ¹ is a hydrogen atom or a polyester structure site, and Xs are each independently the following general formulas (2-1) to (2-8)

(Wherein, R ² is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, and R ³ is each independently a group having 1 to 4 carbon atoms. Is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 or more.)
Is a structural part represented by ]
Wherein at least one of R ¹ present in the resin is a polyester structure site, and the content of the polyester structure site in the resin is in the range of 25 to 45% by mass. A curable composition comprising a polyester-modified epoxy resin (A1) and a polyglycidyl ether of an aliphatic hydrocarbon (A2) as essential components. The curable composition according to claim 1, wherein an epoxy group equivalent of the polyester-modified epoxy resin (A1) is in a range of 400 to 1200 g / equivalent. The aliphatic hydrocarbon polyglycidyl ether (A2) has the following general formula (4)

(Y is an aliphatic hydrocarbon group having 4 to 20 carbon atoms.)
The curable composition according to claim 1, having a molecular structure represented by the following formula. The epoxy resin (A) contains a urethane-modified epoxy resin (A3) or a rubber-modified epoxy resin (A4) in addition to the polyester-modified epoxy resin (A1) and the polyglycidyl ether of an aliphatic hydrocarbon (A2). The curable composition according to any one of claims 1 to 3. A cured product obtained by curing the curable composition according to claim 1. An adhesive comprising the curable composition according to claim 1. A structure comprising the adhesive according to claim 6.

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