Two-part adhesive composition, bonded laminate, and motor

Abstract

Provided are: a two-part adhesive composition that includes a first liquid and a second liquid, wherein the first liquid contains a (meth)acrylate compound and an organic peroxide, the second liquid contains a (meth)acrylate compound and an anaerobic curing accelerator that contains vanadium, and at least one of the first liquid and the second liquid contains a polymer that has a weight average molecular weight of 5,000 or more and includes at least one radically polymerizable group; a bonded laminate which is obtained by laminating and bonding two or more steel sheets by means of the two-part adhesive composition; and a motor which is provided with the bonded laminate.

Description

Two-component adhesive composition, adhesive laminate, and motor

[0001] The present disclosure relates to a two-component adhesive composition, an adhesive laminate, and a motor.

[0002] To reduce the weight of automobiles and electronic devices, there is a demand for adhesives to assemble components. Adhesives of various curing types are used, including heat-curing, ultraviolet (UV)-curing, moisture-curing (including instant adhesives), and anaerobic-curing.

[0003] Examples of conventional adhesive compositions include those described in Patent Documents 1 to 3. Patent Document 1 describes the curing of a substrate pre-coated with a metal catalyst using an anaerobic adhesive. Patent Document 2 describes anaerobic curing that involves the application and drying of a primer containing an organic solvent. Patent Document 3 describes a two-component anaerobic adhesive that cures at room temperature by mixing a component containing a metal complex with a component containing an organic peroxide.

[0004] JP 2016-117851 A International Publication No. 2019 / 123885 Japanese Patent Application Laid-Open No. 59-4667

[0005] Anaerobic adhesives can be cured at room temperature and have attracted attention for applications such as laminating electromagnetic steel sheets during motor core manufacturing. In electromagnetic steel sheet lamination applications, steel sheets coated with a large amount of processing oil must be bonded together to achieve strength. Furthermore, solvent-free adhesives are desirable from the perspectives of low environmental impact, fire safety, and health and safety. The adhesive composition described in Patent Document 1 requires prior application of an organic solvent-containing curing accelerator to the substrate, and the curing is described only for mating applications, with no mention or description of bonding laminates. Furthermore, the adhesive composition described in Patent Document 2 requires a primer treatment containing an organic solvent and a drying process for the processing oil on the steel sheet, making it unsuitable for bonding oily surfaces. Furthermore, Patent Document 3 discloses an adhesive composition that does not contain organic solvents, but its composition and metal components are extremely limited, and its adhesion to oily surfaces is insufficient.

[0006] The problem to be solved by the present disclosure is to provide a two-component adhesive composition that has an excellent curing rate at room temperature (25°C) and excellent adhesion to oily surfaces. Another problem to be solved by the present disclosure is to provide an adhesive laminate and a motor that use the two-component adhesive composition.

[0007] Means for solving the above problems include the following aspects. <1> A two-component adhesive composition comprising a first liquid and a second liquid, wherein the first liquid contains a (meth)acrylate compound and an organic peroxide, the second liquid contains a (meth)acrylate compound and an anaerobic curing accelerator containing vanadium, and at least one of the first liquid and the second liquid contains a polymer having a weight-average molecular weight of 5,000 or more and having at least one radically polymerizable group. <2> The two-component adhesive composition according to <1>, wherein both the first liquid and the second liquid contain a polymer having a weight-average molecular weight of 5,000 or more and having at least one radically polymerizable group. <3> The two-component adhesive composition according to <1> or <2>, wherein the polymer has two or more radically polymerizable groups per molecule. <4> The two-component adhesive composition according to any one of <1> to <3>, wherein the polymer has a urethane bond in its molecular skeleton. <5> The two-component adhesive composition according to any one of <1> to <4>, wherein the glass transition temperature of the polymer is less than 25°C. <6> The two-component adhesive composition according to any one of <1> to <5>, wherein the anaerobic curing accelerator is a compound in which at least one compound selected from the group consisting of ethylhexanoic acid, acetylacetone, and dibutyl phosphate is bonded to or coordinated with vanadium. <7> The two-component adhesive composition according to any one of <1> to <6>, wherein either the first component or the second component further contains a phenylhydrazine compound and a benzsulfonimide compound. <8> The two-component adhesive composition according to any one of <1> to <7>, wherein the first component and the second component each contain an organic solvent in an amount of less than 0.1% by mass, relative to the total mass of the first component or the second component. <9> An adhesive laminate obtained by bonding and laminating two or more steel sheets with the two-component adhesive composition according to any one of <1> to <8>. <10> A motor comprising the adhesive laminate according to <9>.

[0008] According to the present disclosure, it is possible to provide a two-component adhesive composition that has an excellent curing rate at room temperature (25° C.) and excellent adhesion to oily surfaces. Furthermore, according to the present disclosure, it is possible to provide an adhesive laminate and a motor that use the two-component adhesive composition.

[0009] The following description of the constituent elements may be based on representative embodiments of the present disclosure, but the present disclosure is not limited to such embodiments. In this specification, the term "to" is used to mean that the numerical values ​​before and after it are included as upper and lower limits. In numerical ranges described in stages in this specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with a value shown in an example. In this disclosure, "mass %" and "wt %" are synonymous, and "parts by mass" and "parts by weight" are synonymous. In this disclosure, a combination of two or more preferred aspects is a more preferred aspect. The contents of this disclosure will be described in detail below.

[0010] (Two-component adhesive composition) The two-component adhesive composition according to the present disclosure comprises a first component and a second component, wherein the first component contains a (meth)acrylate compound and an organic peroxide, the second component contains a (meth)acrylate compound and an anaerobic curing accelerator containing vanadium, and at least one of the first component and the second component contains a polymer having a weight-average molecular weight of 5,000 or more and having at least one radically polymerizable group. Furthermore, the two-component adhesive composition according to the present disclosure is an anaerobic curing adhesive composition and can be suitably used as an anaerobic curing adhesive composition for steel sheets.

[0011] The two-component adhesive composition according to the present disclosure is a two-component adhesive composition, containing a (meth)acrylate compound in both the first and second components, an organic peroxide in the first component, and an anaerobic curing accelerator containing vanadium in the second component, and at least one of the first and second components contains a polymer having a weight-average molecular weight of 5,000 or more and at least one radically polymerizable group. While the precise mechanism is unclear, the adhesive performance is not affected even in the presence of oils, and the adhesive is capable of curing at room temperature (25°C) in a short time. Therefore, it is presumed that the adhesive exhibits excellent adhesion even on oil-adhered surfaces. Furthermore, the two-component adhesive composition according to the present disclosure has an excellent curing rate (fast curing) at room temperature, and does not require a drying process to dry the oil adhering to the adhesive surface, enabling the production of adhesive products with high production efficiency.

[0012] The two-component adhesive composition according to the present disclosure has excellent adhesion to oily surfaces and can therefore be suitably used in the production of adhesive laminates in which steel sheets are bonded together, motor cores, motors, etc.

[0013] <First Liquid> The first liquid contains a (meth)acrylate compound and an organic peroxide.

[0014] <<(Meth)acrylate Compound>> The (meth)acrylate compound in the present disclosure is a compound other than a polymer having a weight-average molecular weight of 5,000 or more and having at least one radically polymerizable group. The (meth)acrylate compound may be a monofunctional (meth)acrylate compound or a bifunctional or higher polyfunctional (meth)acrylate compound, but is preferably a monofunctional (meth)acrylate compound from the viewpoints of curing speed and adhesion to oily surfaces.

[0015] Examples of the monofunctional (meth)acrylate compound include lauryl (meth)acrylate, stearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, nonylphenoxytetraethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, butoxytriethylene glycol (meth)acrylate, 2-ethylhexyl ... xyl polyethylene glycol (meth)acrylate, nonylphenyl polypropylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, glycerol (meth)acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, modified butyl (meth)acrylate, epichlorohydrin-modified phenoxy (meth)acrylate, ethylene oxide-modified phthalic acid (meth)acrylate, ethylene oxide-modified succinic acid (meth)acrylate, 2-acryloyloxyethyl phthalic acid, caprolactone-modified 2-hydroxyethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, morpholino (meth)acrylate, and the like.

[0016] Of these, from the viewpoint of adhesive strength to metal materials, it is preferable to contain at least one compound selected from the group consisting of 2-hydroxyethyl (meth)acrylate, isobornyl (meth)acrylate, morpholino (meth)acrylate, N-phenylmaleimide, and tetrahydrofurfuryl (meth)acrylate, and it is more preferable to contain at least two compounds selected from the group consisting of 2-hydroxyethyl (meth)acrylate, isobornyl (meth)acrylate, morpholino (meth)acrylate, N-phenylmaleimide, and tetrahydrofurfuryl (meth)acrylate.

[0017] Furthermore, from the viewpoints of adhesive strength and adhesion to metal materials, the monofunctional ethylenically unsaturated compound preferably includes a monofunctional ethylenically unsaturated compound having a hydroxy group, and more preferably includes a monofunctional (meth)acrylate compound having a hydroxy group. Preferred examples of the monofunctional ethylenically unsaturated compound having a hydroxy group include the monofunctional ethylenically unsaturated compounds described above that have a hydroxy group. The first liquid may contain one or more of the monofunctional ethylenically unsaturated compounds having a hydroxy group. From the viewpoints of anaerobic curability and adhesive strength, the content of the monofunctional ethylenically unsaturated compound (particularly the monofunctional ethylenically unsaturated compound having a hydroxy group) is preferably 1% by mass to 90% by mass, more preferably 5% by mass to 85% by mass, even more preferably 10% by mass to 80% by mass, and particularly preferably 15% by mass to 75% by mass, relative to the total mass of the first liquid. Furthermore, from the viewpoints of the viscosity of the composition, the adhesion of the cured product, and the adhesive strength, the content of the monofunctional ethylenically unsaturated compound (particularly the monofunctional ethylenically unsaturated compound having a hydroxy group) is preferably 15% by mass or more, and more preferably 40% by mass or more, relative to the total mass of the first liquid.

[0018] The polyfunctional (meth)acrylate compound is not particularly limited, and examples thereof include 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, ethylene oxide-modified neopentyl glycol di(meth)acrylate, propylene oxide-modified neopentyl glycol di(meth)acrylate, hydroxypivalic acid ester neopentyl glycol diacrylate, caprolactone-modified hydroxypivalic acid ester neopentyl glycol diacrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, stearic acid-modified pentaerythritol di(meth)acrylate, and dicyclopentenyl di(meth)acrylate. , ethylene oxide modified dicyclopentenyl di(meth)acrylate, di(meth)acryloyl isocyanurate, dimethylol tricyclodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene oxide modified trimethylolpropane tri(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, epichlorohydrin modified trimethylolpropane tri(meth)acrylate acrylate, epichlorohydrin-modified glycerol tri(meth)acrylate, tris(acryloyloxyethyl)isocyanurate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, alkyl-modified dipentaerythritol pentaacrylate, dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0019] The polyfunctional (meth)acrylate compound preferably contains a tri- or higher functional polyfunctional (meth)acrylate compound from the viewpoints of curability and adhesive strength. Furthermore, the number of functionalities in the polyfunctional ethylenic compound is not particularly limited, but from the viewpoints of curability and adhesive strength, it preferably contains a tri- to 10-functional ethylenically unsaturated compound, more preferably a tri- to 9-functional ethylenically unsaturated compound, even more preferably a tri- to 8-functional ethylenically unsaturated compound, and particularly preferably a tri- to 6-functional ethylenically unsaturated compound.

[0020] The molecular weight of the (meth)acrylate compound is preferably less than 5,000, more preferably less than 3,000, even more preferably less than 1,000, and particularly preferably 100 or more and less than 1,000. Furthermore, from the viewpoints of curability and adhesion speed, the (meth)acrylate compound is preferably a methacrylate compound.

[0021] The first liquid may contain one type of (meth)acrylate compound alone or two or more types, but from the viewpoint of adhesive strength, it is preferable to contain two or more types, and more preferably two types. From the viewpoints of anaerobic curing property and adhesive speed, the content of the (meth)acrylate compound is preferably 1% by mass to 90% by mass, more preferably 5% by mass to 85% by mass, even more preferably 10% by mass to 80% by mass, and particularly preferably 15% by mass to 75% by mass, relative to the total mass of the first liquid.

[0022] <<Organic Peroxides>> Examples of organic peroxides include hydroperoxides such as cumene hydroperoxide, t-butyl hydroperoxide, p-methane hydroperoxide, methyl ethyl ketone peroxide, cyclohexane peroxide, dicumyl peroxide, and diisopropylbenzene hydroperoxide, as well as other organic peroxides such as ketone peroxides, diallyl peroxides, and peroxy esters. Of these, hydroperoxides are preferably used from the viewpoint of storage stability.

[0023] From the viewpoint of excellent anaerobic curing properties, the organic peroxide is preferably an organic peroxide having a one-hour half-life temperature in the range of 80° C. to 300° C., more preferably an organic peroxide having a one-hour half-life temperature in the range of 100° C. to 200° C. The one-hour half-life temperature is a value measured by thermal decomposition in benzene at a peroxide concentration of 0.1 mol / L.

[0024] Examples of the organic peroxides having a one-hour half-life temperature in the range of 80° C. to 300° C. include hydroperoxides. Specific examples of the hydroperoxides include p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, and t-butyl hydroperoxide.

[0025] The first liquid may contain one organic peroxide alone or two or more organic peroxides. From the viewpoints of anaerobic curability and adhesive strength, the content of the organic peroxide is preferably 0.01% by mass to 10.0% by mass, more preferably 0.1% by mass to 8.0% by mass, and particularly preferably 0.5% by mass to 5.0% by mass, relative to the total mass of the first liquid.

[0026] <<Polymer having a weight-average molecular weight of 5,000 or more and having at least one radically polymerizable group>> At least one of the first and second liquids contains a polymer having a weight-average molecular weight of 5,000 or more and having at least one radically polymerizable group. It is preferable that both the first and second liquids contain the polymer, as this allows the first and second liquids to have similar viscosities and thereby enhance miscibility. The weight-average molecular weight of the polymer is 5,000 or more, and from the viewpoint of adhesion to oily surfaces, it is preferably 7,000 to 100,000, more preferably 10,000 to 90,000, and particularly preferably 10,000 to 80,000. In the present invention, the term "molecular weight" refers to the weight-average molecular weight measured by GPC (gel permeation chromatography) and converted using polystyrene as a standard substance.

[0027] The radical polymerizable group in the polymer is preferably an ethylenically unsaturated group from the viewpoints of curability and adhesion speed. Examples of the ethylenically unsaturated group include a (meth)acryloxy group, a (meth)acrylamide group, a vinyl group, a vinyl ester group, and a vinyl ether group. Among these, from the viewpoints of curability and adhesion speed, a (meth)acryloxy group is preferred, and a methacryloxy group is more preferred.

[0028] From the viewpoints of curability and adhesion speed, the polymer preferably has two or more radically polymerizable groups in one molecule, more preferably has two to eight radically polymerizable groups in one molecule, even more preferably has two to five radically polymerizable groups in one molecule, and particularly preferably has two radically polymerizable groups in one molecule.

[0029] The polymer is not particularly limited, but from the viewpoint of adhesion to oily surfaces, it is preferably at least one compound selected from the group consisting of urethane (meth)acrylate, epoxy (meth)acrylate, ester (meth)acrylate, isoprene-based (meth)acrylate, hydrogenated isoprene-based (meth)acrylate, and (meth)acrylic group-containing acrylic polymer, more preferably urethane (meth)acrylate or epoxy (meth)acrylate, even more preferably urethane (meth)acrylate, and particularly preferably urethane methacrylate. Furthermore, from the viewpoint of adhesion to oily surfaces, it is preferable that the polymer has a urethane bond in its molecular skeleton.

[0030] The structure of the urethane (meth)acrylate is not particularly limited, and for example, an aliphatic urethane (meth)acrylate that does not have a monomer structural unit having an aromatic structure, an aromatic urethane (meth)acrylate that has a monomer structural unit having an aromatic structure, etc. Examples of monomers that can be used to prepare the urethane (meth)acrylate are shown below, and these monomers may be combined to form the desired urethane (meth)acrylate.

[0031] The urethane (meth)acrylate may be a reaction product of a polyhydric alcohol, a polyisocyanate, and a hydroxy(meth)acrylate compound, or a reaction product of a polyisocyanate and a hydroxy(meth)acrylate compound without using a polyhydric alcohol. Specific examples of the polyhydric alcohol include polyether polyols such as polypropylene glycol and polytetramethylene glycol, polyester polyols obtained by reacting a polyhydric alcohol with a polybasic acid, caprolactone polyols obtained by reacting a polyhydric alcohol with a polybasic acid and ε-caprolactone, and polycarbonate polyols (e.g., polycarbonate polyols obtained by reacting 1,6-hexanediol with diphenyl carbonate). Specific examples of organic polyisocyanates include alicyclic isocyanates such as isophorone diisocyanate and dicyclopentanyl diisocyanate, aliphatic isocyanates such as hexamethylene diisocyanate, and aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, and diphenylmethane-4,4'-diisocyanate. As the urethane (meth)acrylate, those produced from polyether polyol, polyester polyol, or polycarbonate polyol as the raw polyol are preferred because of their excellent weather resistance, transparency, and adhesive strength. As the raw organic polyisocyanate, those produced from isophorone diisocyanate, hexamethylene diisocyanate, or xylene diisocyanate are preferred because of their excellent weather resistance.

[0032] Examples of the urethane (meth)acrylate include urethane (meth)acrylates having a polybutadiene skeleton, urethane (meth)acrylates having a hydrogenated polybutadiene skeleton, urethane (meth)acrylates having a polycarbonate skeleton, urethane (meth)acrylates having a hydrogenated bisphenol A skeleton, urethane (meth)acrylates having a polyether skeleton, urethane (meth)acrylates having a polyester skeleton, and urethane (meth)acrylates having a castor oil skeleton.

[0033] Examples of epoxy (meth)acrylates include (meth)acrylates obtained by reacting a conventionally known epoxy resin, such as an aromatic epoxy resin, an alicyclic epoxy resin, or an aliphatic epoxy resin, with (meth)acrylic acid.

[0034] From the viewpoint of adhesion to oily surfaces, the glass transition temperature of the polymer is preferably less than 25°C, more preferably 10°C or lower, particularly preferably 0°C or lower, and may be -15°C or lower. The lower limit of the glass transition temperature of the polymer is not particularly limited, but may be, for example, -80°C. The glass transition temperature (Tg) of the polymer can be determined from the intersection of the baseline of a heat flux curve obtained using a differential scanning calorimeter and the tangent at the inflection point. The measurement may be performed using the following measuring equipment and conditions. The heat flux curve is obtained by heating approximately 5 mg of a sample to 70°C at 20°C / min, holding it for 5 minutes, cooling it to -150°C at -20°C / min, holding it for 5 minutes, and then heating it again to 70°C at 20°C / min. <Measurement Equipment and Measurement Conditions> Measurement equipment: DSC 214 Polymer manufactured by NETZSCH Measurement atmosphere: Nitrogen atmosphere

[0035] The first liquid may contain one or more polymers having a weight-average molecular weight of 5,000 or more and at least one radically polymerizable group. From the viewpoint of adhesion to oily surfaces, the content of the polymer having a weight-average molecular weight of 5,000 or more and at least one radically polymerizable group is preferably 5% by mass to 90% by mass, more preferably 10% by mass to 80% by mass, and particularly preferably 20% by mass to 70% by mass, relative to the total mass of the first liquid. From the viewpoint of viscosity adjustment, the content of the polymer having a weight-average molecular weight of 5,000 or more and at least one radically polymerizable group is preferably 50% by mass or less.

[0036] <<Other Anaerobic Curing Accelerators>> From the viewpoints of anaerobic curability and curing rate, it is preferable that the first liquid further contains an anaerobic curing accelerator other than the vanadium-containing anaerobic curing accelerator. The other anaerobic curing accelerator is a compound that can activate the vanadium-containing anaerobic curing accelerator contained in the second liquid. Such other anaerobic curing accelerators are usually organic compounds. Examples of the other anaerobic curing accelerators include benzsulfimide compounds, amine compounds, azole compounds, mercaptan compounds, hydrazine compounds, and salts thereof. Among these, from the viewpoints of anaerobic curability and curing rate, a combination of a benzsulfimide compound and a hydrazine compound is preferable, and a combination of a benzsulfimide compound and a phenylhydrazine compound is more preferable.

[0037] Examples of the benzsulfimide compound include saccharin (o-benzsulfimide) and N-methylsaccharin.

[0038] Examples of the amine compound include heterocyclic secondary amines such as 1,2,3,4-tetrahydroquinoline and 1,2,3,4-tetrahydroquinaldine, heterocyclic tertiary amines such as quinoline, methylquinoline, quinaldine and quinoxalinephenazine, and aromatic tertiary amines such as N,N-dimethyl-anisidine, N,N-dimethylaniline and N,N'-dimethyl-p-toluidine.

[0039] Examples of the azole compounds include 1,2,4-triazole, oxazole, oxadiazole, thiadiazole, benzotriazole, hydroxybenzotriazole, benzoxazole, 1,2,3-benzothiadiazole, and 3-mercaptobenzotriazole.

[0040] Examples of the mercaptan compound include linear mercaptans such as n-dodecyl mercaptan, ethyl mercaptan, and butyl mercaptan.

[0041] Examples of the hydrazine compounds include 1-acetyl-2-phenylhydrazine, 1-acetyl-2(p-tolyl)hydrazine, 1-benzoyl-2-phenylhydrazine, 1-(1',1',1'-trifluoro)acetyl-2-phenylhydrazine, 1,5-diphenyl-carbohydrazine, 1-formyl-2-phenylhydrazine, 1-acetyl-2-(p-bromophenyl)hydrazine, 1-acetyl-2-(p-nitrophenyl)hydrazine, 1-acetyl-2-(2'-phenylethylhydrazine), p-nitrophenylhydrazine, p-trisulfonylhydrazide, etc. Furthermore, examples of salts of the hydrazine compounds include 4-methylsulfonylphenylhydrazine hydrochloride, hydrazine monohydrochloride, p-tolylhydrazine hydrochloride, etc.

[0042] The first liquid may contain one or more of the other anaerobic curing accelerators. From the viewpoints of anaerobic curability and adhesive strength, the content of the other anaerobic curing accelerator(s) is preferably 0.01% by mass to 30% by mass, more preferably 0.05% by mass to 10% by mass, and particularly preferably 0.05% by mass to 1% by mass, relative to the total mass of the first liquid.

[0043] <<Adhesion Promoter>> From the viewpoint of adhesive strength, it is preferable that the first liquid further contains an adhesion promoter. The adhesion promoter does not directly cure the anaerobic adhesive, but is a component that improves the adhesive strength of the anaerobic adhesive. The adhesion promoter may be a compound containing a functional group or element that can chemically or physically interact with the metal contained in the adherend. Specific examples of adhesion promoters include unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, silane coupling agents, etc. Examples of unsaturated carboxylic acids include (meth)acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and monoalkyl esters of unsaturated dicarboxylic acids (monoalkyl esters of maleic acid, fumaric acid, itaconic acid, citraconic acid, etc.). Examples of unsaturated carboxylic acid anhydrides include maleic anhydride, itaconic anhydride, citraconic anhydride, 4-methylphthalic anhydride, etc. Among these, (meth)acrylic acid is preferred from the viewpoints of heat resistance and adhesion to metal materials.

[0044] Examples of the silane coupling agent include, but are not limited to, γ-chloropropyltrimethoxysilane, octenyltrimethoxysilane, glycidoxyoctyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, p-styryltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, and 3-aminopropyltrimethoxysilane.

[0045] The first liquid may contain one adhesion promoter alone or two or more adhesion promoters, but from the viewpoints of adhesive strength, heat resistance, and adhesion to metal materials, it preferably contains an unsaturated carboxylic acid and a silane coupling agent. From the viewpoints of anaerobic curing property and adhesive strength, the content of the adhesion promoter is preferably 0.01% by mass to 15% by mass, more preferably 0.05% by mass to 10% by mass, and particularly preferably 0.1% by mass to 5% by mass, relative to the total mass of the first liquid.

[0046] <<Organic Solvent>> From the viewpoint of adhesion to oily surfaces, the first liquid preferably contains an organic solvent in an amount of less than 0.1% by mass, and more preferably does not contain an organic solvent, relative to the total mass of the first liquid. Specific examples of the organic solvent include aromatic organic solvents such as toluene and xylene, aliphatic organic solvents such as n-hexane, alicyclic organic solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane, ketone organic solvents such as acetone and methyl ethyl ketone, alcohol organic solvents such as methanol and ethanol, ester organic solvents such as ethyl acetate and butyl acetate, and propylene glycol ether organic solvents such as propylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol t-butyl ether.

[0047] <<Other Components>> The first liquid may contain, as other components in addition to those described above, additives such as fillers, various elastomers, storage stabilizers, antioxidants, light stabilizers, heavy metal deactivators, tackifiers, plasticizers, antifoaming agents, pigments, rust inhibitors, leveling agents, dispersants, rheology modifiers, and flame retardants, within the scope of the present disclosure.

[0048] The first liquid may contain a filler to the extent that it does not impair storage stability, for the purpose of improving the elastic modulus, flowability, etc. of the cured product. Specific examples of the filler include organic powders and inorganic powders.

[0049] The inorganic powder filler is not particularly limited, but examples thereof include glass, fumed silica, alumina, mica, ceramics, silicone rubber powder, calcium carbonate, aluminum nitride, carbon powder, kaolin clay, dried clay minerals, dried diatomaceous earth, etc. The content of the inorganic powder is preferably 0.1 parts by mass to 100 parts by mass per 100 parts by mass of the polymerization components (the total content of the (meth)acrylate compound, the polymer, and other ethylenically unsaturated compounds; the same applies hereinafter).

[0050] Fumed silica is blended for the purpose of adjusting viscosity or improving the mechanical strength of the cured product. Preferably, fumed silica surface-treated with dimethylsilane, trimethylsilane, alkylsilane, methacryloxysilane, organochlorosilane, polydimethylsiloxane, hexamethyldisilazane, or the like is used. Commercially available fumed silica products include, for example, Aerosil (registered trademark) R972, R972V, R972CF, R974, R976, R976S, R9200, RX50, NAX50, NX90, RX200, RX300, R812, R812S, R8200, RY50, NY50, RY200S, RY200, RY300, R104, R106, R202, R805, R816, T805, R711, RM50, and R7200 (all manufactured by Nippon Aerosil Co., Ltd.).

[0051] The organic powder filler is not particularly limited, but examples thereof include polyethylene, polypropylene, nylon (registered trademark), cross-linked acrylic, cross-linked polystyrene, polyester, polyvinyl alcohol, polyvinyl butyral, polycarbonate, etc. The content of the organic powder is preferably 0.1 to 100 parts by mass per 100 parts by mass of the polymerizable components.

[0052] The first liquid may contain a storage stabilizer. Examples of storage stabilizers that can be added include radical polymerization inhibitors such as benzoquinone, hydroquinone, and hydroquinone monomethyl ether, and metal chelating agents such as ethylenediaminetetraacetic acid or its disodium salt, oxalic acid, acetylacetone, and o-aminophenol. From the viewpoint of storage stability, the first liquid preferably contains a radical polymerization inhibitor, and more preferably contains at least one selected from the group consisting of hydroquinone and hydroquinone monomethyl ether. The content of the storage stabilizer is preferably 0.0001 to 1 part by mass per 100 parts by mass of the polymerization components.

[0053] The first liquid may contain an antioxidant, such as quinone compounds such as β-naphthoquinone, 2-methoxy-1,4-naphthoquinone, methylhydroquinone, hydroquinone, hydroquinone monomethyl ether, mono-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, and 2,5-di-tert-butyl-p-benzoquinone; phenothiazine, 2,2-methylene-bis(4-methyl-6-tert-butylphenol), catechol, and tert-butylcatechol. , 2-butyl-4-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate, 4,4'-butylidenebis(6-tert-butyl-3-methylphenol), 4,4'-thiobis(6-tert-butyl-3-methylphenol), 3,9- Bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N, N'-Hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, C7-C9 side chain alkyl ester, 2,4-dimethyl-6-(1-methylpentadecyl)phenol, diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6-tolyl)tri-p-cresol, calcium diethyl bis[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonate, 4,6-bis(octylthiomethyl)-o-cresol, ethylene bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate], hexamethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-tris(3, 5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, reaction products of N-phenylbenzenamine and 2,4,6-trimethylpentene, 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazine phenols such as tris(2,4-di-tert-butylphenyl)phosphite, tris[2-[[2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphen-6-yl]oxy]ethyl]amine, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl phosphorus compounds such as diester phosphorous acid, tetrakis(2,4-di-tert-butylphenyl)[1,1-bisphenyl]-4,4'-diylbisphosphonite, 6-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-tert-butyldibenz[d,f][1,3,2]dioxaphosphine; dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,Examples of suitable compounds include sulfur compounds such as 3'-thiodipropionate, pentaerythrityl tetrakis(3-laurylthiopropionate), and 2-mercaptobenzimidazole; amine compounds such as phenothiazine; lactone compounds; and vitamin E compounds. Among these, phenolic compounds are preferred.

[0054] The viscosity of the first liquid at 25°C is preferably 10,000 mPa·s or less, more preferably 5 mPa·s to 9,000 mPa·s, even more preferably 10 mPa·s to 8,000 mPa·s, and particularly preferably 15 mPa·s to 7,000 mPa·s, from the viewpoint of the ease with which the first liquid applied to the metal material spreads and the first liquid does not excessively spill out from the bonding surface during lamination. From the viewpoint of the curing rate, the viscosity is preferably 3,000 Pa·s or less. The viscosity measurement method in the present disclosure is as follows: A specified amount of the first liquid or the second liquid is sampled and dispensed into a measuring cup. The viscosity is measured using an EHD viscometer (manufactured by Toki Sangyo Co., Ltd.) at 25°C and a shear rate of 76.6 (1 / s).

[0055] <Second Liquid> The second liquid contains a (meth)acrylate compound and an anaerobic curing accelerator containing vanadium. Like the first liquid, the second liquid may contain a polymer having a weight-average molecular weight of 5,000 or more and at least one radically polymerizable group. Except as described below, the (meth)acrylate compound, polymer having a weight-average molecular weight of 5,000 or more and at least one radically polymerizable group, adhesion promoter, organic solvent, and other components in the first liquid are synonymous with the (meth)acrylate compound, polymer having a weight-average molecular weight of 5,000 or more and at least one radically polymerizable group, adhesion promoter, organic solvent, and other components in the second liquid, and preferred embodiments are also the same. Unless otherwise specified, these common components that can be blended into the first and second liquids may be the same or different in the first and second liquids, and may be blended in both the first and second liquids, or only in the first or second liquid. It is preferable that a component that is blended as an essential component in only one of the first and second liquids is not blended in the other. For example, the first liquid may contain an organic peroxide, but the second liquid preferably does not contain an organic peroxide. Also, for example, the second liquid may contain an anaerobic curing accelerator containing vanadium, but the first liquid preferably does not contain an anaerobic curing accelerator containing vanadium. In addition, other anaerobic curing accelerators that are optional components of the first liquid, such as benzsulfimide compounds and hydrazine compounds, activate the anaerobic curing accelerator containing vanadium in the second liquid and shorten the curing time, so from the perspective of handling the adhesive, it is preferable that they are not blended in the second liquid.

[0056] From the viewpoints of curability and adhesion speed, it is preferable that the polymers contained in the first liquid and the second liquid each have two or more radically polymerizable groups in one molecule. Also, from the viewpoint of oily surface adhesion, it is preferable that the polymers contained in the first liquid and the second liquid each have a urethane bond in their molecular skeleton. Furthermore, from the viewpoint of oily surface adhesion, it is preferable that the glass transition temperatures of the polymers contained in the first liquid and the second liquid each be less than 25°C. From the viewpoint of oily surface adhesion, it is preferable that the content of organic solvents in both the first liquid and the second liquid is less than 0.1% by mass relative to the total mass of the first liquid or the second liquid.

[0057] <<Vanadium-Containing Anaerobic Curing Accelerator>> Examples of vanadium-containing anaerobic curing accelerators can be selected from compounds such as inorganic compounds, organic compounds, and complexes containing vanadium. Examples of inorganic compounds include vanadium oxides such as vanadium dioxide and vanadium pentoxide, and mineral acid salts such as vanadyl sulfate, vanadyl nitrate, vanadium trichloride, vanadium tetrachloride, vanadyl dichloride, vanadyl trichloride, vanadium tribromide, and vanadium triiodide. Examples of vanadates include sodium vanadate and ammonium vanadate. Examples of organic compounds include organic acid salts such as vanadium oxalate, vanadium ethylhexanoate, and vanadium dibutyl phosphate, and alkoxides such as vanadium triethoxide. Examples of the complexes include vanadium acetylacetonate, vanadyl acetylacetonate, bis(cyclopentadienyl)vanadium, bis(cyclopentadienyl)vanadium chloride, cyclopentadienylvanadium tetracarbonyl, vanadium hexacarbonyl, and the like, as well as vanadium complexes in which various ligands are coordinated to vanadium.

[0058] Among these, from the viewpoints of oily surface adhesion and curing rate, the vanadium-containing anaerobic curing accelerator is preferably a compound in which at least one compound selected from the group consisting of organic acids and 1,3-diketones (preferably acetylacetone) is bonded to or coordinated with vanadium, preferably a compound in which at least one compound selected from the group consisting of carboxylic acids, dialkyl phosphates, and acetylacetone is bonded to or coordinated with vanadium, and particularly preferably a compound in which at least one compound selected from the group consisting of ethylhexanoic acid, acetylacetone, and dibutyl phosphate is bonded to or coordinated with vanadium. That is, from the viewpoints of oily surface adhesion and curing rate, the vanadium-containing anaerobic curing accelerator is preferably a vanadium organic acid salt or vanadium acetylacetonate, more preferably a vanadium carboxylate, vanadium dialkyl phosphate, or vanadium acetylacetonate, and particularly preferably vanadium ethylhexanoate, vanadium dibutyl phosphate, or vanadium acetylacetonate.

[0059] The second liquid may contain one or more vanadium-containing anaerobic curing accelerators. From the viewpoints of adhesion to oily surfaces and curing speed, the content of the vanadium-containing anaerobic curing accelerator is preferably 0.006% by mass to 15% by mass, more preferably 0.008% by mass to 10% by mass, and particularly preferably 0.1% by mass to 5% by mass, relative to the total mass of the second liquid.

[0060] The vanadium-containing anaerobic curing accelerator has the function of initiating a curing reaction upon contact with the organic peroxide contained in the first liquid. Metals other than vanadium can also function as anaerobic curing accelerators, and the second liquid may contain an anaerobic curing accelerator containing a metal other than vanadium (particularly, transition metal elements such as Cu, Mn, Co, etc.). To ensure uniform mixing of the second liquid, the content of the anaerobic curing accelerator containing a metal other than vanadium (particularly, transition metal elements such as Cu, Mn, Co, etc.) may be reduced, and may be less than 0.01% by mass, more specifically, less than 0.006% by mass, relative to the total mass of the second liquid. Furthermore, like the vanadium-containing anaerobic curing accelerator, the anaerobic curing accelerator containing a metal other than vanadium is preferably not contained in the first liquid, as is the case with the second liquid.

[0061] The viscosity of the second liquid at 25°C is preferably 10,000 mPa·s or less, more preferably 5 to 9,000 mPa·s, even more preferably 10 to 8,000 mPa·s, and particularly preferably 15 to 7,000 mPa·s, from the viewpoints of the ease with which the second liquid applied to the metal material spreads and the second liquid does not excessively spill out from the bonding surface during lamination. From the viewpoint of curing speed, the viscosity is preferably 3,000 Pa·s or less. Furthermore, the viscosity of the second liquid at 25°C is preferably 0.5 to 2.0 times the viscosity of the first liquid at 25°C, and more preferably 0.7 to 1.5 times the viscosity of the first liquid at 25°C.

[0062] The ratio of the first liquid to the second liquid used is not particularly limited as long as adhesion is possible, but is preferably 20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30, and particularly preferably 40 / 60 to 60 / 40 in mass ratio.

[0063] The method for producing the two-component adhesive composition according to the present disclosure is not particularly limited, and the composition can be produced by a known method. For example, the first and second components can be produced by blending predetermined amounts of each component and mixing them using a mixing means such as a mixer at a temperature of preferably 10°C to 100°C for preferably 0.1 to 5 hours.

[0064] (Adhesive Laminate) The adhesive laminate according to the present disclosure may be any adhesive laminate formed by bonding using the two-component adhesive composition according to the present disclosure. Preferably, the adhesive laminate is formed by bonding and laminating two or more metal materials using the two-component adhesive composition according to the present disclosure. More preferably, the adhesive laminate is formed by bonding and laminating two or more steel sheets using the two-component adhesive composition according to the present disclosure. Other suitable examples include adhesive laminates formed by bonding two or more threaded members (e.g., screws and threaded holes) or two or more interlocking members (e.g., protruding members and recessed members, rod members and hole members, etc.) using the two-component adhesive composition according to the present disclosure. Among metal materials, the two-component adhesive composition according to the present disclosure is suitable for bonding steel sheets. The steel sheet is not particularly limited, and preferred examples include electrical steel sheets and cold-rolled steel sheets. The electrical steel sheet may be either oriented or non-oriented, but non-oriented electrical steel sheets are preferred when used for motor cores, rotors, stators, etc., as described below.

[0065] The adhesive laminate according to the present disclosure can be used for various purposes without any particular limitation. Among these, the adhesive laminate according to the present disclosure is suitably used for motor cores and the like because it is insulated by the cured product of the two-component adhesive composition according to the present disclosure, has low current loss, high performance and high reliability, and distributes stress over a surface, preventing stress concentration and strain concentration.

[0066] The method for producing the adhesive laminate according to the present disclosure is not particularly limited, but preferably includes the steps of applying the two-component adhesive composition according to the present disclosure to at least one of the adherends to be bonded, and laminating another adherend to the adherend to which the two-component adhesive composition has been applied. The application of the two-component adhesive composition according to the present disclosure to the adherends may involve applying the first and second components to only one of the adherends, or applying the first component to one of the adherends and the second component to the other adherend, or discharging the components while mixing them using a mixing device such as a screw just before use and applying them to the adherends. From the viewpoint of further demonstrating the effects of the present disclosure, the adherends are preferably made of a metal material.

[0067] After the step of laminating another adherend, the two-component adhesive composition can be heated to cure in a shorter time. The heating method is not particularly limited, but examples include a thermostatic bath and a far-infrared heater. The temperature and time during heating may be any conditions that allow sufficient curing, but heating is preferably performed at a temperature of 40°C to 300°C, more preferably 60°C to 150°C, for 10 seconds to 3 hours, more preferably 20 seconds to 60 minutes. When placing the adhesive laminate in the thermostatic chamber, it is preferable to fix it in advance with a fixture or the like to prevent misalignment.

[0068] The method for applying the two-component adhesive composition is not particularly limited, and known methods can be used, such as roller application, dispensing, spraying, inkjet application, and dipping.

[0069] An example of a method for producing an adhesive laminate using the two-component adhesive composition will be described below.

[0070] Unless otherwise specified, the manufacturing method described below may be carried out by appropriately changing the order of steps and conditions depending on the adhesive laminate to be manufactured, and further steps may be added.

[0071] The number of layers of the adhesive laminate obtained in the manufacturing method described below is not particularly limited. When an adhesive laminate having three or more layers is manufactured in the manufacturing method described below, the adhesive laminate can be manufactured by sequentially stacking and adhering metal adherends. An unfinished adhesive laminate that has not reached the desired number of layers has layers including already-adhered metal adherends, and an adhesive laminate can be manufactured by stacking and adhering an unlaminated metal adherend to the uppermost or lowermost layer. When such metal adherends are sequentially stacked and adhered, the uppermost or lowermost layer of the unfinished adhesive laminate can be considered to be the metal adherend.

[0072] In one embodiment, a method for manufacturing an adhesive laminate includes the steps of preparing a first metal substrate having a first liquid and a second liquid applied to at least one surface thereof, and superimposing the surface of the first metal substrate to which the first liquid and the second liquid have been applied onto a second metal substrate.

[0073] In one embodiment, a method for manufacturing an adhesive laminate includes the steps of preparing a first metal substrate having a first liquid applied to at least one surface thereof, preparing a second metal substrate having a second liquid applied to at least one surface thereof, and overlapping the surface of the first metal substrate having the first liquid applied thereto with the surface of the second metal substrate having the second liquid applied thereto.

[0074] In one embodiment, a method for producing an adhesive laminate includes the steps of: (1) preparing a plurality of metal substrates each having a first liquid and a second liquid applied to one side thereof; and (2) stacking the plurality of metal substrates prepared in step (1) so that the surfaces coated with the first liquid and the second liquid come into contact with the surfaces not coated with the first liquid and the second liquid.

[0075] In one embodiment, a method for manufacturing an adhesive laminate includes the steps of (1) preparing a plurality of first adherend metals, (2) preparing a plurality of second adherend metals having a first liquid and a second liquid applied to both sides thereof, and (3) alternately stacking the first adherend metals and the second adherend metals so that the first adherend metals come into contact with the surfaces of the second adherend metals coated with the first liquid and the second liquid.

[0076] Alternatively, a laminate of the metal substrates may be formed before applying at least one of the first liquid and the second liquid to the metal substrates, and then the first liquid or the second liquid that has not been applied may be provided between the metal substrates to bond the metal substrates that form the laminate.

[0077] Simply laminating the metal substrates may leave gaps large enough to allow the two-component adhesive composition to penetrate between them. Therefore, the two-component adhesive composition can be permeated into the laminate by spraying the two-component adhesive composition onto the side of the laminate or by impregnating the laminate with the first and second components, respectively. Alternatively, an injection nozzle can be inserted between the metal substrates, and the two-component adhesive composition (first and second components) can be injected directly between the metal substrates. When applying the two-component adhesive composition between the metal substrates, it is desirable to physically fix the laminate from the outside.

[0078] In one embodiment, a method for producing an adhesive laminate includes the steps of: (1) preparing a laminate in which at least two or more metal substrates are stacked; (2) supplying a first liquid between the metal substrates of the laminate; and (3) supplying a second liquid between the metal substrates of the laminate.

[0079] In one embodiment, a method for producing an adhesive laminate includes a step (1) of laminating metal substrates to prepare a laminate, and a step (2) of providing a two-component adhesive composition (first and second components) between the metal substrates of the laminate.

[0080] When an adhesive laminate is produced using an electromagnetic steel sheet as the adherend metal, a method is generally used in which a hoop material is continuously or intermittently fed and the adherend metal obtained by punching is sequentially laminated. Using any of the above-mentioned adhesive laminate production methods, it is possible to continuously laminate and adhere electromagnetic steel sheets from the hoop material.

[0081] For example, an adhesive laminate of magnetic steel sheets can be produced by a method for producing an adhesive laminate including the steps of: (1) applying a two-component adhesive composition (first and second components) to one side of a hoop material; (2) punching the hoop material to produce a metal substrate of a predetermined shape; and (3) sequentially stacking the resulting metal substrates. In this method, the step of (4) applying a press working oil to at least one side of the hoop material may be carried out before punching.

[0082] The present disclosure will be specifically described below based on examples. However, the present disclosure is not limited to these examples. In the following, "parts" and "%" mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0083] (Examples 1 to 8 and Comparative Examples 1 to 5) The components shown in Table 1 were mixed in the amounts shown in Table 1 using a mixer at room temperature (25°C) for 60 minutes to obtain the first and second liquids (two-part adhesive compositions) of Examples 1 to 8 and Comparative Examples 1 to 5, respectively.

[0084] The units of each value shown in Table 1 are parts by mass.

[0085] Details of the abbreviations used in Table 1 are as follows: UMA-1: Aliphatic difunctional urethane methacrylate (weight average molecular weight: 11,000, glass transition temperature: -19°C) UMA-2: Aliphatic difunctional urethane methacrylate (weight average molecular weight: 3,200, glass transition temperature: 8°C) EMA-1: Difunctional epoxy methacrylate (weight average molecular weight: 700, glass transition temperature: 114°C) UMA-3: Aliphatic difunctional urethane methacrylate (weight average molecular weight: 12,000, glass transition temperature: -10°C) UMA-4: Aromatic trifunctional urethane methacrylate (weight average molecular weight: 42,000, glass transition temperature: -34°C) IBXMA: Isobornyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd. HEMA: 2-hydroxyethyl methacrylate, manufactured by Mitsubishi Gas Chemical Company, Inc. AA: Acrylic acid, manufactured by Toagosei Co., Ltd. KBM-503: 3-methacryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. KBM-403: 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd. Saccharin: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. AcPh: acetylphenylhydrazine, manufactured by Tokyo Chemical Industry Co., Ltd. MQ: 4-methoxyphenol, manufactured by Kawaguchi Chemical Industry Co., Ltd. CHP: cumene hydroperoxide, manufactured by NOF Corporation, Percumyl H80 DBP-V: vanadium dibutyl phosphate (reaction product of vanadium pentoxide and dibutyl phosphate) Vacac: vanadium acetylacetonate, manufactured by Aldrich Cu-EHA: copper 2-ethylhexanoate, manufactured by Strem Chemicals Mn-EHA: manganese 2-ethylhexanoate, manufactured by Strem Chemicals Co-EHA: Cobalt 2-ethylhexanoate, manufactured by Strem Chemicals

[0086] <Preparation of Adhesive Laminate> Two electromagnetic steel sheets (35H300L manufactured by Nippon Steel Corporation) were prepared. Both electromagnetic steel sheets were degreased with acetone. Processing oil was applied to one side of one electromagnetic steel sheet, and processing oil was applied to one side of the other electromagnetic steel sheet. Equal amounts of the first and second two-component adhesive compositions were applied to separate electromagnetic steel sheets in this order, so that the total film thickness after curing was 10 μm or less. Immediately after applying the second component, the two electromagnetic steel sheets were bonded together, clamped with double clips, and left to stand at 25°C for 2 minutes, 5 minutes, or 24 hours to prepare test specimens. A tensile shear test was performed on the test specimens according to the method described below, and shear strength was measured. Test specimens were also prepared in the same manner as above, except that processing oil was not applied to the two electromagnetic steel sheets. A tensile shear test was performed on the test specimens according to the method described below, and shear strength was measured.

[0087] <Tensile shear test> Using a Strograph 20-C manufactured by Toyo Seiki Seisakusho, Ltd., the shear strength was measured by pulling the test piece at 10 mm / min at room temperature (25°C), and the measurement results are shown in Table 1. The higher the shear strength value after 24 hours in the presence of processing oil, the better the adhesion to oily surfaces. Furthermore, the higher the shear strength value after standing for 2 minutes and 5 minutes, especially after 2 minutes, the better the curing speed at room temperature. The evaluation criteria for curing speed at room temperature are as follows: A: Adhesion strength after 2 minutes is 1 MPa or more B: Adhesion strength after 5 minutes is 0.5 MPa or more and adhesion strength after 2 minutes is less than 1 MPa C: Adhesion strength after 5 minutes is less than 0.5 MPa

[0088]

[0089] The numerical values ​​of each raw material in Table 1 are in parts by mass. The symbol "-" in the tensile shear test indicates that the test was not performed. In Comparative Example 1, insoluble matter was generated in the second liquid, making it impossible to measure the viscosity or perform the tensile shear test.

[0090] The two-component adhesive compositions of Examples 1 to 8 were superior to the two-component adhesive compositions of Comparative Examples 1 to 5 in both curing speed at room temperature (25°C) and adhesion to oily surfaces.

[0091] The disclosure of Japanese Patent Application No. 2023-218084, filed on December 25, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

[0092] The present disclosure is extremely effective and can be utilized in a wide range of products and technical fields, and is industrially useful because it can provide, for example, two-component adhesive compositions for metal bonding applications, two-component adhesive compositions for preventing loosening of screws, two-component adhesive compositions for fitting, and the like, and can also provide adhesive laminates that contribute to improving the performance and reliability of motor rotors and stators.

Claims

1. A two-component adhesive composition comprising a first liquid and a second liquid, wherein the first liquid contains a (meth)acrylate compound and an organic peroxide, the second liquid contains a (meth)acrylate compound and an anaerobic curing accelerator containing vanadium, and at least one of the first liquid and the second liquid contains a polymer having a weight average molecular weight of 5,000 or more and at least one radical polymerizable group.

2. The two-component adhesive composition according to claim 1, wherein both the first liquid and the second liquid contain a polymer having a weight average molecular weight of 5,000 or more and at least one radical polymerizable group.

3. The two-component adhesive composition according to claim 1, wherein the polymer has two or more radical polymerizable groups in one molecule.

4. The two-component adhesive composition according to claim 1, wherein the polymer has a urethane bond in the molecular skeleton.

5. The two-component adhesive composition according to claim 1, wherein the glass transition temperature of the polymer is less than 25°C.

6. The two-component adhesive composition according to claim 1, wherein the anaerobic curing accelerator is a compound in which at least one compound selected from the group consisting of ethylhexanoic acid, acetylacetone, and dibutyl phosphate is bonded or coordinated to vanadium.

7. The two-component adhesive composition according to claim 1, further comprising a phenylhydrazine compound and a benzenesulfonimide compound in either the first liquid or the second liquid.

8. The two-component adhesive composition according to claim 1, wherein both the first liquid and the second liquid have an organic solvent content of less than 0.1% by mass based on the total mass of the first liquid or the second liquid.

9. An adhesive laminate obtained by bonding and laminating two or more steel plates with the two-component adhesive composition according to any one of claims 1 to 8.

10. A motor comprising the adhesive laminate according to claim 9.

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