JP5285419B2 - One-component heat curing epoxy resin adhesive - Google Patents

Description

  The present invention relates to a one-component heat-curable epoxy resin adhesive, and more particularly to a one-component heat-curable epoxy resin adhesive excellent in adhesiveness and heat resistance.

  Conventionally, epoxy resins, unsaturated polyester resins, polyimide resins, phenol resins, polybismaleimide resins, and the like have been used as resins used for adhesives. Among them, epoxy resins are excellent in many respects such as small cure shrinkage, excellent dimensional stability, and strong mechanical strength, and strong adhesion, adhesion and mechanical strength to metals, porcelain, concrete, etc. , It has the characteristics of excellent shear strength, tensile strength and the like. However, since the epoxy resin has insufficient flexibility, there is a problem that the peel strength and impact strength are very low, and cracks, peel, and the like are likely to occur.

As a method for improving impact resistance with respect to an epoxy resin adhesive, Patent Document 1 discloses an epoxy resin, a core-shell type powder polymer in which a core and a shell are made of a (meth) acrylate polymer, and a latent for epoxy resin. An epoxy resin-based adhesive composition containing an adhesive curing agent is disclosed, and specifically, an adhesive composition comprising a bisphenol A type epoxy resin, dicyandiamide, and a core-shell type polymer is described. However, when high heat resistance such as adhesion of electronic parts is required, the above-described adhesive composition has a problem that heat resistance is not sufficient.
JP-A-5-65391

  In order to obtain an adhesive excellent in shear strength and peel strength and excellent in heat resistance, the present inventors are composed of an epoxy resin, a curing agent, and core-shell type acrylic particles, and excellent in heat resistance as an epoxy resin. An attempt was made to produce an adhesive composition using a naphthalene type epoxy resin. However, the adhesive composition using both the naphthalene type epoxy resin and the core-shell type acrylic particles improves the peel adhesive strength but deteriorates the heat resistance, and has an excellent peel adhesive strength and an excellent heat resistance. Could not get.

  An object of the present invention is to provide a one-component heat-curable epoxy resin adhesive having excellent adhesiveness in both shear strength and peel strength and excellent heat resistance.

  In order to solve the above problems, the present inventors have conducted intensive research. As a result, in addition to epoxy resin having a naphthalene skeleton and / or biphenyl skeleton, a curing agent, and core-shell acrylic particles, resin acid-treated calcium carbonate and / or Alternatively, a one-component heat-curable epoxy resin containing aluminum hydroxide and having excellent adhesiveness in both shear strength and peel strength and excellent heat resistance by using imidazoles, dicyandiamide and adipic acid dihydrazide as a curing agent. It has been found that an adhesive can be obtained.

That is, the one-component heat-curable epoxy resin adhesive of the present invention includes (A) at least one epoxy resin selected from the group consisting of an epoxy resin having a naphthalene skeleton and an epoxy resin having a biphenyl skeleton, and (B) imidazole. And one or more imidazoles selected from the group consisting of imidazole derivatives, (C) dicyandiamide, (D) organic acid dihydrazide compounds, (E) resin acid-treated calcium carbonate and metal hydroxides. It is a one-component heat-curable epoxy resin adhesive comprising one or more compounds and (F) core-shell acrylic particles, and the content of the (A) epoxy resin is the total amount of epoxy resin contained in the adhesive. 10 mass% or more and 100 mass% or less with respect to 100 mass parts of epoxy resin contained in the adhesive. (B) 0.1-20 parts by mass of imidazoles, 0.1-30 parts by mass of (C) dicyandiamide, 0.1-20 parts by mass of (D) organic acid dihydrazide compound, (E) compound 10 to 200 parts by mass, and 3 to 100 parts by mass of the (F) core-shell acrylic particles .

The organic acid dihydrazide compound is preferably adipic acid dihydrazide.
It is preferable that the metal hydroxide is aluminum hydroxide.

  According to the one-component heat-curable epoxy resin adhesive of the present invention, the peel adhesive strength by the T-type peel method is 5 kgf / 25 mm or more, and the tensile shear adhesive strength at 23 ° C. when cured at 150 ° C. for 30 minutes. The tensile shear bond strength at 140 ° C. after curing at 150 ° C. for 30 minutes and after heat treatment at 140 ° C. for 15 minutes is 80% or higher than the tensile shear bond strength at 23 ° C. Can have.

  The one-component heat-curable epoxy resin adhesive of the present invention has a remarkable effect that it is excellent in both shear strength and peel strength adhesiveness and heat resistance. Furthermore, the one-component heat-curable epoxy resin adhesive of the present invention is a one-component type, and has an effect of being excellent in workability.

  Embodiments of the present invention will be described below, but these are exemplarily shown, and it goes without saying that various modifications are possible without departing from the technical idea of the present invention.

  The one-component heat-curable epoxy resin adhesive of the present invention includes (A) one or more epoxy resins selected from the group consisting of an epoxy resin having a naphthalene skeleton and an epoxy resin having a biphenyl skeleton, (B) imidazole and imidazole One or more imidazoles selected from the group consisting of derivatives, (C) dicyandiamide, (D) organic acid dihydrazide compounds, (E) one selected from the group consisting of resin acid-treated calcium carbonate and metal hydroxides The above compound and (F) core-shell acrylic particles are contained as essential components.

  The epoxy resin (A) used in the present invention is not particularly limited as long as it has at least one epoxy ring (glycidyl group) in one molecule and has a naphthalene skeleton or a biphenyl skeleton. Although a thing can be used, the thing of epoxy equivalent 90-2000 is suitable.

  Examples of the naphthalene skeleton include 1-glycidylnaphthalene, 2-glycidylnaphthalene, 1,2-diglycidylnaphthalene, 1,5-diglycidylnaphthalene, 1,6-diglycidylnaphthalene, 1,7-diglycidylnaphthalene, A naphthalene skeleton such as 2,7-diglycidylnaphthalene, triglycidylnaphthalene, 1,2,5,6-tetraglycidylnaphthalene is preferable.

  As the epoxy resin having a biphenyl skeleton, one or more of phenols having a biphenyl skeleton, amines having a biphenyl skeleton, or carboxylic acids having a biphenyl skeleton and an epihalohydrin are subjected to a condensation reaction in the presence of an alkali. An epoxy resin obtained by reacting a phenol having a biphenyl skeleton with an epihalohydrin is more preferable.

  Examples of the phenols having a biphenyl skeleton include 4,4′-biphenol, 3,3′-dimethyl-4,4′-biphenol, 3,5-dimethyl-4,4′-biphenol, and 3,3 ′. -Dibutyl-4,4'-biphenol, 3,5-dibutyl-4,4'-biphenol, 3,3'-diphenyl-4,4'-biphenol, 3,3'-dibromo-4,4'-biphenol 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol, 3,3′-dimethyl-5,5′-dibutyl-4,4′-biphenol, 3,3 ′, 5,5 4,4'-dihydroxybiphenyls such as '-tetrabutyl-4,4'-biphenol, 3,3', 5,5'-tetrabromo-4,4'-biphenol; these various 4,4'-dihydroxys Biphenyl Polyhydric resins obtained by condensation reaction of aldehydes with various aldehydes such as formaldehyde, acetaldehyde, propyl aldehyde, butyraldehyde, benzaldehyde, hydroxybenzaldehyde, crotonaldehyde, glyoxal; phenol, cresol, xylenol, propylphenol, bromophenol Bisphenol A, bisphenol F, bisphenol AD, hydroquinone, methylhydroquinone, dimethylhydroquinone, dibutylhydroquinone, resorcin, methylresorcin, biphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, phenol novolac resin, cresol novolac resin, bisphenol A novolac resin, dicyclopentadiene Phenolic resin, te Various phenols such as penphenol resin, phenol aralkyl resin, naphthol novolak resin, and aldehydes containing various biphenyl skeletons such as biphenyl-4,4′-dialdehyde and 4-hydroxybiphenyl-4′-aldehyde Polyhydric phenol resins obtained by condensation reaction; polyhydric phenol resins obtained by condensation reaction of the above various phenols with 4,4′-dihydroxymethylbiphenyl, 4,4′-diisopropenylbiphenyl, etc. Can be mentioned.

These epoxy resins (A) may be used independently and may be used together 2 or more types. When two or more types of epoxy resins (A) are used in combination, the combination is not particularly limited, and two or more types of epoxy resins having a naphthalene skeleton may be used in combination, or two or more types of epoxy resins having a biphenyl skeleton may be used in combination. Alternatively, one or more epoxy resins having a naphthalene skeleton and one or more epoxy resins having a biphenyl skeleton may be used in combination.
The epoxy resin (A) is preferably liquid, but a liquid epoxy resin and a solid epoxy resin may be used in combination.

  An epoxy resin other than the epoxy resin (A) described above may be further added to the one-component heat-curable epoxy resin adhesive of the present invention. In the adhesive of the present invention, the epoxy resin (A) is 10% by mass or more based on the total amount of epoxy resins (that is, the epoxy resin (A) and other epoxy resins) contained in the adhesive of the present invention. It is preferable that the content is 100% by mass or less. Heat resistance can be remarkably improved by including 10 mass% or more of epoxy resins (A). From the viewpoint of workability, another epoxy resin may be added as a diluent.

The imidazole (B) used in the present invention is one or more selected from the group consisting of imidazole and imidazole derivatives.
Examples of the imidazole and imidazole derivatives include imidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-undecylimidazole, and 2-dimethylimidazole. 2-heptadecylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl 2-undecylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 1-cyanoethyl-2-methylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-S-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1')]- Ethyl-S-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1 ')]-ethyl-S-triazine, 1-cyanoethyl-2-ethyl-4-methylimidazole Trimellitate, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-dodecyl-2-methyl-3-benzoylimidazolium chloride, 1,3-dibenzyl-2-methylimidazolium chloride, 2,4-diamino Imidazole derivatives such as -6- [2'-methylimidazole- (1 ')]-ethyl-s-triazine and isocyanuric acid adducts are preferred.

  The blending ratio of the imidazoles (B) is not particularly limited, but is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 18 parts by mass with respect to 100 parts by mass of the epoxy resin contained in the adhesive of the present invention. Parts, more preferably 0.5 to 15 parts by mass.

Examples of the dicyandiamide (C) include dicyandiamide and derivatives thereof. As the dicyandiamide derivative, a polyepoxide addition-modified product, an amidation-modified product, a Mannich-modified product, or a Michael addition-modified product can be used.
The blending ratio of the dicyandiamide (C) is not particularly limited, but is preferably 0.1 to 30 parts by mass, more preferably 0.2 to 28 parts by mass with respect to 100 parts by mass of the epoxy resin contained in the adhesive of the present invention. More preferably, it is blended at a ratio of 0.5 to 25 parts by mass.

  As said organic acid dihydrazide compound (D), a carboxylic acid dihydrazide compound or a dibasic acid dihydrazide compound is preferable, and a carboxylic acid dihydrazide compound is more preferable. As the carboxylic acid dihydrazide, dicarboxylic acid dihydrazides such as adipic acid dihydrazide, succinic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide and octadecadiene-dicarbohydrazide are preferable, and adipic acid dihydrazide is more preferable.

  The organic acid dihydrazide compound (D) is preferably in the form of particles. By using a particulate organic acid dihydrazide compound, it is easy to raise the temperature at the time of heat-curing, and when it reaches a predetermined temperature, it can be easily dissolved in the epoxy resin and the curing reaction can proceed. The average particle diameter of the organic acid dihydrazide compound (D) is preferably 100 μm or less, and more preferably 5 to 50 μm. By making the average particle diameter 100 μm or less, it is preferable that the temperature is easily raised during the curing and the dissolution becomes easy. Fine particles having an average particle size of 100 μm or less can be appropriately obtained from commercially available products. Furthermore, in order to obtain fine particles, it is preferable to make them fine by an impact pulverization method or a spray drying method. In the present specification, the “average particle size” means a value obtained by measuring the particle size and frequency distribution of the pulverized particles and calculating those values as a mass average.

  The organic acid dihydrazide compound (D) may be used alone or in combination of two or more. The blending ratio of the organic acid dihydrazide compound (D) is not particularly limited, but is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 0.2 parts by weight with respect to 100 parts by weight of the epoxy resin contained in the adhesive of the present invention. 18 parts by mass, more preferably 0.5 to 15 parts by mass.

The present invention includes one or more compounds (E) selected from the group consisting of resin acid-treated calcium carbonate and metal hydroxide as the inorganic filler.
The compounding ratio of the compound (E) is not particularly limited, but the resin acid-treated calcium carbonate and the metal hydroxide are used with respect to 100 parts by mass of the epoxy resin contained in the adhesive of the present invention in terms of heat resistance and workability. The total amount of the product is preferably 10 to 200 parts by mass.

  The resin acid-treated calcium carbonate is calcium carbonate obtained by surface-treating resin acids. The resin acid-treated calcium carbonate may have a structure that covers all or part of the surface of the raw material calcium carbonate particles or the treated calcium carbonate particles with resin acids, and it is necessary to continuously cover the entire surface. There is no. Further, the processing order is not limited.

Known calcium carbonate, synthetic (precipitating) calcium carbonate, or the like can be used as the calcium carbonate that is a raw material for the resin acid-treated calcium carbonate.
Examples of the resin acids include abietic acids such as abietic acid, dehydroabietic acid, and dihydroabietic acid or polymers thereof, disproportionated rosin, hydrogenated rosin, polymerized rosin, and salts thereof (for example, alkali metal salts, alkalis) Earth metal salts) or esters.

There is no restriction | limiting in particular in the surface treatment method of the calcium carbonate by a resin acid, A well-known processing method can be used. Although there is no restriction | limiting in particular in the adhesion amount of resin acid, 0.5-20 mass parts is preferable with respect to 100 mass parts of calcium carbonate used as a raw material, and 1-15 mass parts is more preferable.
The average particle diameter of the resin acid-treated calcium carbonate is preferably 0.01 to 20 μm, and more preferably 0.02 to 15 μm.

Although there is no restriction | limiting in particular as said metal hydroxide, For example, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, a composite metal hydroxide, etc. are mentioned, From a heat resistant and flame-retardant viewpoint, aluminum hydroxide From the viewpoint of moisture resistance in addition to heat resistance, magnesium hydroxide and composite metal hydroxide are preferred. These metal hydroxides may be used without surface treatment, or may be used after surface treatment with a treatment agent such as a coupling agent, a fatty acid and a resin acid. Moreover, you may use what was coat | covered with resin, such as a thermosetting resin.
The average particle size of the metal hydroxide is preferably 0.50 to 60 μm, and more preferably 0.70 to 30 μm.

When magnesium hydroxide is used as the metal hydroxide, the higher the purity and the more regular crystal structure is preferable, and the hexagonal plate shape is more preferable.
Although there is no restriction | limiting in particular as a composite metal hydroxide, The compound shown by the following compositional formula (I) is preferable.
^{_{p (M 1 a O b)}} · q (M 2 c O d) · r (M 3 c O d) · mH 2 O ··· (I)
(Here, M ¹ , M ² and M ³ represent different metal elements, a, b, c, d, p, q and m are positive numbers, and r is 0 or a positive number.)
M ¹ , M ² and M ^{3 in the} composition formula (I) are not particularly limited as long as they are different metal elements, but from the viewpoint of flame retardancy, M ¹ is a metal element of the third period, group IIA Preferably selected from metal elements belonging to the alkaline earth metal elements, group IVB, group IIB, group VIII, group IB, group IIIA and group IVA, and M ² is selected from transition metal elements of groups IIIB to IIB, More preferably, M ¹ is selected from magnesium, calcium, aluminum, tin, titanium, iron, cobalt, nickel, copper and zinc, and M ² is selected from iron, cobalt, nickel, copper and zinc. From the viewpoint of fluidity, it is preferable that M ¹ is magnesium, M ² is zinc or nickel, and r = 0. The molar ratio of p, q and r is not particularly limited, but preferably r = 0 and p / q is 1/99 to 1/1.

  As the core-shell acrylic particles (F), core-shell (meth) acrylate polymer particles having a core and a shell made of a (meth) acrylate polymer are used. As the core-shell acrylic particles (F), known core-shell type (meth) acrylate polymer particles can be used. The (meth) acrylate polymer forming the core has a glass transition temperature of −30 ° C. or lower. It is preferable that the (meth) acrylate polymer comprising the rubber-like polymer and forming the shell comprises a glass-like polymer having a glass transition temperature of 70 ° C. or higher.

  The particle diameter of the core-shell acrylic particles (F) is preferably 30 μm or less. By using core-shell acrylic particles having a particle size of 30 μm or less, the stress relaxation property can be remarkably improved. Core-shell acrylic particles obtained using a core having a mass average particle diameter of 0.1 to 3.0 μm are more preferable. Although there is no restriction | limiting in the composition ratio of the core in a core-shell acrylic particle (F), It is suitable that a core shall be 20-80 mass% and a shell shall be 80-20 mass%.

  The production method of the core-shell acrylic particles (F) is not particularly limited, and a known production method can be used. For example, it is preferably produced by a continuous multi-stage seed emulsion polymerization method having two or more stages. Alternatively, the seed latex prepared in the first stage may be partially agglomerated by solvent coagulation or the like, and then graft polymerized thereon to form a shell.

An example of a method for producing the core-shell acrylic particles (F) will be described below.
First, a (meth) acrylate monomer is polymerized with other monomers that can be copolymerized as necessary to prepare (meth) acrylate polymer particles that serve as a core.
The (meth) acrylate monomer is preferably a (meth) acrylate monomer having an alkyl group having 2 to 8 carbon atoms, such as ethyl acrylate, propyl acrylate, n-butyl acrylate, cyclohexyl acrylate, 2 -Ethyl hexyl acrylate, ethyl methacrylate, butyl methacrylate, etc. are mentioned, These may be used independently and may be used in combination of 2 or more type.
Examples of the other copolymerizable monomer include compounds having an unsaturated bond, specifically, compounds having two or more double bonds, such as ethylene glycol diacrylate and ethylene glycol dimethacrylate. , Butylene glycol diacrylate, butylene glycol dimethacrylate, trimethylolpropane diacrylate, trimethylolpropane dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, hexanediol diacrylate, hexanediol methacrylate, oligoethylenediacrylate, oligo Ethylene dimethacrylate, divinyl benzene, trimellitic acid triallyl and triallyl isocyanurate, etc .; styrene, vinyl toluene, α-methyls Aromatic vinyl compounds such as len; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; and vinylidene cyanide, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxybutyl acrylate, 2-hydroxyethyl fuma Rate, hydroxybutyl vinyl ether, monobutyl maleate, glycidyl methacrylate, butoxyethyl methacrylate, and the like can be suitably used, and compounds having two or more double bonds are more preferable. These may be used alone or in combination of two or more. The amount used is preferably in the range of 50% by mass or less with respect to the total mass of the monomers.

The obtained (meth) acrylate polymer particles are used as a core, and a (meth) acrylate monomer is graft-copolymerized with other copolymerizable monomers as described above, if necessary. By carrying out emulsion polymerization to form a shell, a latex containing a core-shell type (meth) acrylate polymer is obtained. By spray-drying the latex, a core-shell type (meta-methacrylate) having excellent dispersibility in an epoxy resin is obtained. ) Acrylate polymer particles can be obtained.
Alternatively, it may be prepared by partially aggregating a seed latex containing the obtained (meth) acrylate polymer to be the core, and then graft-polymerizing the seed latex. A wet cake prepared by coagulating and separating latex particles by freezing and dehydrating can be dried in a fluidized bed or the like to obtain aggregated particles.

  As the (meth) acrylate monomer used for forming the shell, a (meth) acrylate monomer having an alkyl group having 1 to 4 carbon atoms is preferable, for example, ethyl acrylate, n-butyl acrylate, Examples thereof include methyl methacrylate and butyl methacrylate, and these may be used alone or in combination of two or more.

  The core-shell acrylic particles (F) may be used alone or in combination of two or more. The blending ratio of the core-shell acrylic particles (F) is not particularly limited, but is preferably 3 to 100 parts by weight, and preferably 5 to 80 parts by weight with respect to 100 parts by weight of the epoxy resin contained in the adhesive of the present invention. It is more preferable that 8 to 50 parts by mass is more preferable.

In addition to the above components, the one-component heat-curable epoxy resin adhesive of the present invention may contain various additives as necessary.
Examples of the additive include plasticizers, softeners, thixotropic agents, pigments, dyes, anti-aging agents, antioxidants, antistatic agents, flame retardants, dispersants, solvents, and the like.
Examples of the plasticizer or softener include epoxy-based reactive plasticizers such as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and glycidyl methacrylate. Examples of the thixotropic property-imparting agent include dry silica, white carbon, hydrogenated castor oil, and the like. Examples of the pigment include inorganic pigments such as titanium dioxide, zinc oxide, ultramarine, bengara, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride and sulfate; organic pigments such as azo pigments and copper phthalocyanine pigments. Can be mentioned. Examples of the anti-aging agent include hindered phenol compounds and hindered amine compounds. Examples of the antioxidant include butylhydroxytoluene and butylhydroxyanisole. Examples of the antistatic agent include quaternary ammonium salts; hydrophilic compounds such as polyglycols and ethylene oxide derivatives. Examples of the flame retardant include chloroalkyl phosphate, dimethyl methylphosphonate, bromine, phosphorus compound, ammonium polyphosphate, neopentyl bromide-polyether, brominated polyether, and the like.

  The one-component heat-curable epoxy resin adhesive of the present invention has excellent T-type peel strength without impairing heat resistance and mechanical properties, so that it can be used in aerospace fields, advanced technology fields such as electronics, It can be used for a wide range of applications such as automobiles and in-vehicle applications.

  The present invention will be described more specifically with reference to the following examples. However, it is needless to say that these examples are shown by way of illustration and should not be construed in a limited manner.

Example 1
Naphthalene type epoxy resin (trade name “EPICLON (registered trademark) HP-4032”, manufactured by DIC Corporation) 80 parts by mass, dicyclopentadiene type epoxy resin as a diluent (trade name “Adeka Resin EP-4088S”, manufactured by ADEKA Corporation) ) 20 parts by weight, dicyandiamide (trade name “Dyhard (registered trademark) 100SH”, manufactured by Degussa Japan Co., Ltd.) 8 parts by weight, adipic acid dihydrazide (trade name “ADH”, manufactured by Nippon Kasei Co., Ltd.), 2 parts by weight, modified imidazole 3 parts by mass (trade name “Adeka Hardener EH3366S”, manufactured by ADEKA Corporation) and 50 parts by mass of resin acid-treated synthetic calcium carbonate (trade name “NEOLIGHT SA-100”, manufactured by Takehara Chemical Industries, Ltd.) Evenly dispersed. Next, 10 parts by mass of bisphenol F type epoxy resin (trade name “jER (registered trademark) 807”, manufactured by Japan Epoxy Resin Co., Ltd.), 20 parts by mass of core shell type acrylic rubber particles (trade name “Zephiac F351”, manufactured by Gantz Kasei) Part, and 1 part by mass of a silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd.) as an adhesion-imparting agent, and mixing with a vacuum planetary stirrer, paste-like one-component heat curing Type epoxy resin adhesive composition was prepared. The composition of the adhesive composition is shown in Table 1.

The following test was done with respect to the obtained adhesive composition. The results are shown in Table 2.
1. Adhesion Test (1-1) Peel Adhesion Strength Using the obtained adhesive composition, the peel adhesion strength by the T-type peeling method was measured according to JIS K6854-3. Adhesion conditions and measurement conditions are as follows.
・ Substrate 0.5 mm thick mild steel plate 25 mm × 200 mm
・ Adhesion condition Apply the adhesive composition on the surface of the adherend, spread it thinly, bond it under the conditions of a temperature of 23 ° C. and a relative humidity of 50%, and the width of the adhesive layer after bonding is 0.2 mm. Two places were clamped with a pinch of 30 mm. The bonding area was 2.5 mm × 160 mm. The bonded adherend was allowed to stand at 150 ° C. for 30 minutes to obtain a T-type peel test specimen.
-Measurement conditions About the obtained test body, according to JISK6854-3, the T-type peeling adhesive strength was measured with the holding | grip movement speed of 50 mm / min.

(1-2) Tensile shear bond strength Tensile shear bond strength was measured at a test speed of 2.5 mm / min according to JISK6850 using the obtained adhesive composition. Adhesion conditions and measurement conditions are as follows.
・ Exhibiting body 1.5mm thick mild steel plate 25mm × 100mm
・ Adhesion condition Apply the adhesive composition on the surface of the body and stretch it thinly, and paste it under the conditions of a temperature of 23 ° C. and a relative humidity of 50%. The width of the adhesive layer after bonding is 0.2 mm. 8 places were clamped with 30mm pinches. The bonding area was 2.5 mm × 25 mm. The bonded adherend was allowed to stand at 150 ° C. for 30 minutes to obtain a tensile shear test specimen.
-Measurement conditions About the obtained test body, according to JISK6850, the test speed | rate 2.5 mm / min and the tensile shear bond strength in 23 degreeC were measured. The measured values are shown in the table as before heat treatment.

2. Heat Resistance Test Using the obtained adhesive composition, the tensile shear bond strength at 140 ° C. was measured. First, the test body was produced by the same method as the tensile shear bond strength test. Each specimen was left in an atmosphere of 140 ° C. for 15 minutes, and then the tensile shear bond strength was measured under the condition of 140 ° C. The measured values are shown in the table after heat treatment.

Furthermore, the intensity | strength retention calculated by following formula (1) was shown in the table | surface.
Strength retention (%) = S ₁ / S ₂ × 100 (1)
In the formula (1), S ₁ is a measured value of shear bond strength at 140 ° C. after heat treatment at 140 ° C. for 15 minutes, and S ₂ is a measured value of shear bond strength at 23 ° C. before heat treatment. It is.

(Examples 2 to 20 and Comparative Examples 1 to 10)
As shown in Tables 1, 3, 5, 7, and 9, an adhesive composition was prepared in the same manner as in Example 1 except that the blended materials were changed. The measurement was performed in the same manner as in Example 1 for the obtained adhesive composition. The results are shown in Tables 2, 4, 6, 8, and 10.

The blending ratio in Table 1 is shown in parts by mass, and the contents of each component are as follows.
* 1) Epoxy resin 1: Naphthalene type epoxy resin (trade name “EPICLON (registered trademark) HP-4032”, manufactured by DIC Corporation)
* 2) Epoxy resin 2: Biphenyl type epoxy resin (trade name “jER (registered trademark) YL6677”, manufactured by Japan Epoxy Resin Co., Ltd.)
* 3) Imidazoles B1: Modified imidazole (trade name “ADEKA HARDNER EH3366S”, manufactured by ADEKA Corporation)
* 4) Imidazoles B2: Modified imidazole (trade name “ADEKA HARDNER EH4346S”, manufactured by ADEKA Corporation)
* 5) Imidazoles B3: 2-Phenyl-4,5-dihydroxymethylimidazole (trade name “Cureazole (registered trademark) 2PHZ-PW”, manufactured by Shikoku Kasei Kogyo Co., Ltd.)
* 6) Dicyandiamide: Trade name “Dyhard (registered trademark) 100SH” manufactured by Degussa Japan * 7) Adipic acid dihydrazide: Trade name “ADH”, manufactured by Nippon Kasei Co., Ltd. * 8) Calcium carbonate E1: Resin acid treatment synthesis Calcium carbonate (trade name “NEOLIGHT SA-100”, manufactured by Takehara Chemical Industries, Ltd.)
* 9) Core-shell acrylic particles: Core-shell type acrylic rubber particles (trade name “Zefiac F351”, manufactured by Ganz Kasei Co., Ltd.)
* 10) Epoxy resin 1: dicyclopentadiene type epoxy resin (trade name “ADEKA RESIN EP-4088S”, manufactured by ADEKA Corporation)
* 11: Epoxy resin 2: Bisphenol F type epoxy resin (trade name “jER (registered trademark) 807”, manufactured by Japan Epoxy Resin Co., Ltd.)
* 12) Epoxy resin 3: bisphenol A type epoxy resin (trade name “Epototo YD-8125”, manufactured by Tohto Kasei Co., Ltd.)
* 13) Epoxy resin 4: bisphenol F type epoxy resin (trade name “Epototo YD-8170C”, manufactured by Toto Kasei Co., Ltd.)
* 14) Adhesion imparting agent: Silane coupling agent (trade name “KBM-403”, manufactured by Shin-Etsu Chemical Co., Ltd., epoxy silane)

The blending ratio in Table 3 is shown in parts by mass, * 1, 3, 6 to 11 and 14 are the same as in Table 1, and * 15 to 17 are as follows.
* 15) Calcium carbonate E2: Resin acid treated synthetic calcium carbonate
* 16) Calcium carbonate E3: Resin acid treated synthetic calcium carbonate
* 17) Aluminum hydroxide: trade name “Hijilite H-43”, manufactured by Showa Denko KK

  The blending ratio in Table 5 is shown in parts by mass, * 1 to 3, 6 to 11 and 14 are the same as Table 1, and * 17 is the same as Table 3.

The blending ratio in Table 7 is shown in parts by mass, * 1, 3, 6-11 and 14 are the same as in Table 1, and * 18-23 are as follows.
* 18) Epoxy resin 5: bisphenol A type epoxy resin (trade name “jER (registered trademark) 828”, manufactured by Japan Epoxy Resin Co., Ltd.)
* 19: Curing agent 1: Modified polyamine (trade name “FXR-1081”, manufactured by Tohto Kasei Co., Ltd.)
* 20: Inorganic filler 1: Fatty-treated heavy calcium carbonate (trade name “Ryton A5”, manufactured by Shiroishi Calcium Co., Ltd.)
* 21: Inorganic filler 2: Untreated heavy calcium carbonate (trade name “Whiteon SB”, manufactured by Shiraishi Calcium Co., Ltd.)
* 22: Inorganic filler 3: crystalline silica (trade name “Crystallite AA”, manufactured by Tatsumori Co., Ltd.)
* 23: Inorganic filler 4: Alumina (trade name “Alumina AS-50”, manufactured by Showa Denko KK)

  The blending ratio in Table 9 is shown in parts by mass, and * 1, 3, 6-11 and 14 are the same as in Table 1.

  As shown in Tables 2, 4 and 6, the adhesive compositions of Examples 1 to 20 had a peel adhesion strength of 5 kgf / 25 mm or more, and a shear bond strength at 23 ° C. of 16 MPa or more. The adhesive strength was excellent in any of the adhesive strengths, and the shear adhesive strength at 140 ° C. after the heat treatment was 80% or higher than that before the heat treatment, and the heat resistance was also excellent.

Claims (4)

(A) one or more epoxy resins selected from the group consisting of epoxy resins having a naphthalene skeleton and epoxy resins having a biphenyl skeleton,
(B) one or more imidazoles selected from the group consisting of imidazole and imidazole derivatives,
(C) dicyandiamide,
(D) an organic acid dihydrazide compound,
(E) One or more compounds selected from the group consisting of resin acid-treated calcium carbonate and metal hydroxide, and (F) a one-component heat-curable epoxy resin adhesive containing core-shell acrylic particles ,
The content of the (A) epoxy resin is 10% by mass or more and 100% by mass or less with respect to the total amount of the epoxy resin contained in the adhesive,
0.1 to 20 parts by mass of (B) imidazoles, 0.1 to 30 parts by mass of (C) dicyandiamide, and (D) organic acid with respect to 100 parts by mass of epoxy resin contained in the adhesive A one-component heat-curable epoxy resin comprising 0.1 to 20 parts by mass of a dihydrazide compound, 10 to 200 parts by mass of the (E) compound, and 3 to 100 parts by mass of the (F) core-shell acrylic particles. adhesive.   The one-component heat-curable epoxy resin adhesive according to claim 1, wherein the organic acid dihydrazide compound is adipic acid dihydrazide.   The one-component heat-curable epoxy resin adhesive according to claim 1 or 2, wherein the metal hydroxide is aluminum hydroxide.   The peel adhesion strength by T-type peeling method is 5 kgf / 25 mm or more, the tensile shear bond strength at 23 ° C. when cured at 150 ° C. for 30 minutes is 16 MPa or more, and after curing at 150 ° C. for 30 minutes, at 140 ° C. The tensile shear bond strength at 140 ° C after heat treatment for 15 minutes has a strength retention of 80% or more with respect to the tensile shear bond strength at 23 ° C. One-component heat-curable epoxy resin adhesive according to item.