Curable adhesive composition

Abstract

To provide an active energy ray-curable adhesive composition for bonding a metal and a resin, which enables the bonding process to be shortened and is capable of sustaining high peel strength even at high temperature.SOLUTION: The present invention provides a curable adhesive composition for bonding a metal and a resin, wherein the curable adhesive composition includes at least one cationically polymerizable component selected from the group consisting of a cationically polymerizable monomer, a cationically polymerizable oligomer, and a cationically polymerizable polymer, and wherein the cured product of the composition exhibits a storage elastic modulus of 100 MPa or more at 80°C.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a curable adhesive composition, which can be used in various industrial product fields such as the electrical field, the automotive field, and the industrial field, and belongs to these technical fields.

Background Art

[0002] A general packaging material for power storage devices used in laminated batteries has a three-layer structure centered on a metal foil, and an adhesive is used between each layer. The three layers are a base material layer that becomes the outside of the battery after the laminated battery is formed, a barrier layer formed from a metal foil such as aluminum foil or stainless steel foil that prevents the penetration of moisture, air, etc., and a sealant layer for the purpose of insulating so that the barrier layer does not come into contact with the electrodes and electrolytes and heat-sealing and bonding the outer peripheral portion. In some cases, each layer may be formed of two or more layers. Among these, a polyolefin-based resin film such as a polypropylene film is usually used for the sealant layer in contact with the electrolyte.

[0003] For the adhesion between the sealant layer and the metal foil, an adhesive containing an acid-modified polyolefin and a crosslinking agent is generally used. For example, Patent Document 1 describes a laminating adhesive composition characterized by containing a modified polyolefin resin (A), an alcohol-based epoxy compound (B), and a polyfunctional isocyanate compound (C). Further, for example, Patent Document 2 describes an exterior material for a power storage device in which an adhesive layer between the sealant layer and the metal foil is a crosslinked layer having a crosslinked structure in which a polyolefin resin or an acid-modified polyolefin resin is crosslinked via a structure derived from a compound having a (meth)acryloxy group or an allyl group.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] For adhesives that bond adherends of different materials such as metal and resin, like those used for packaging materials for power storage devices, adhesives mainly composed of acid-modified polyolefins are often used. However, there are still problems to be solved in adhesives mainly composed of acid-modified polyolefins.

[0006] The adhesive described in Patent Document 1 takes a long time to cure and requires an aging process of about several days to obtain high adhesive strength.

[0007] The adhesive described in Patent Document 2 can be adhered without an aging process and the adhesion time can be shortened compared to the adhesive of Patent Document 1. However, the adhesive described in Patent Document 2 contains a high content of acid-modified polyolefin. In the adhesive described in Patent Document 2, the acid-modified polyolefin is dissolved in a solvent to be applied to the adherend, and it is necessary to provide a drying process for removing the solvent after application. Further shortening of the adhesion process requires the development of a new adhesive with a reduced amount of solvent used.

[0008] On the other hand, the performance required for adhesives conventionally used for packaging materials for power storage devices, which can maintain high peel strength even at high temperatures in preparation for heat generation during battery abnormalities, is also necessary.

[0009] An object of one embodiment of the present invention is to provide a curable adhesive composition that can shorten the adhesion process and maintain high peel strength even at high temperatures.

MEANS FOR SOLVING THE PROBLEMS

[0010] Means for solving the above problems include the following aspects. [1] A curable adhesive composition for bonding a metal and a resin, comprising: at least one cationic polymerizable component selected from the group consisting of a cationic polymerizable monomer, a cationic polymerizable oligomer, and a cationic polymerizable polymer, and having a storage modulus at 80 °C of 100 MPa or more for the cured product of the composition. A curable adhesive composition. [2] The curable adhesive composition according to [1], wherein the storage modulus at 120 °C of the cured product of the composition is 10 MPa or more. [3] The curable adhesive composition according to [1] or [2], further comprising at least one radical polymerizable component selected from the group consisting of a radical polymerizable monomer, a radical polymerizable oligomer, and a radical polymerizable polymer. [4] The curable adhesive composition according to [3], containing 40% by mass or more and 80% by mass or less of the radical polymerizable component. [5] The curable adhesive composition according to [3] or [4], wherein the radical polymerizable component is an alicyclic polyfunctional acrylate. [6] The curable adhesive composition according to any one of [1] to [5], wherein the resin is a polyolefin. [7] The curable adhesive composition according to any one of [1] to [6], which is an active energy ray curable adhesive composition. [8] The curable adhesive composition according to any one of [1] to [6], which is an adhesive composition for a power storage device packaging material. [Advantages of the Invention]

[0011] According to the present invention, a curable adhesive composition for bonding a metal and a resin can be obtained, which can shorten the bonding process and maintain a high peel strength even at high temperatures. [Brief Description of the Drawings]

[0012]

Figure 1

Figure 2

Best Mode for Carrying Out the Invention

[0013] The description of the constituent elements given below may be based on representative embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, "~" is used to mean including the numerical values described before and after it as the lower limit value and the upper limit value.

[0014] In the numerical ranges described step by step in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0015] In this specification, an oligomer and a polymer are compounds having a linear structural part in which a plurality of monomer units are continuously bonded in the molecule, and a monomer is a compound that does not contain such a structural part. The oligomer and the polymer may be a homopolymer or a copolymer. The number of monomer units contained in the oligomer and the polymer is preferably 5 or more, more preferably 10 or more. The weight average molecular weight of the oligomer and the polymer is preferably more than 1500, more preferably 2000 or more. The oligomer and the polymer are distinguished by the weight average molecular weight, and the oligomer is defined as having a weight average molecular weight of less than 10000, and the polymer is defined as having a weight average molecular weight of 10000 or more. Here, the value of the weight average molecular weight means the value obtained by converting the molecular weight measured by gel permeation chromatography (hereinafter also referred to as "GPC") into polystyrene. For example, the values measured under the following apparatus and conditions can be used. Apparatus: Model name "HLC-8320" manufactured by Tosoh Corporation Column: Three TSKgel-SuperMultipore HZ-M (4.6 mm ID × 15 cm) manufactured by Tosoh Corporation Solvent: Tetrahydrofuran Column temperature: 40°C Detector: RI (Differential refractive index detector) Flow rate: 350 μL / min

[0016] Hereinafter, the curable adhesive composition of the present invention will be described for each constituent component. In the following, the "curable adhesive composition" may be abbreviated as "adhesive composition".

[0017] The storage modulus at 25°C of the cured product of the adhesive composition is preferably 2000 MPa or more, more preferably 2500 MPa or more, and particularly preferably 2800 MPa or more. The storage modulus at 25°C of the cured product is preferably 4000 MPa or less, more preferably 3500 MPa or less, and particularly preferably 3300 MPa or less. By having the storage modulus at 25°C of the cured product within these ranges, the peel strength at elevated temperatures is improved.

[0018] The storage modulus at 80°C of the cured product of the adhesive composition is 100 MPa or more, preferably 200 MPa or more, and more preferably 300 MPa or more. The storage modulus at 80°C of the cured product is preferably 1000 MPa or less, more preferably 800 MPa or less, and particularly preferably 750 MPa or less. By having the storage modulus at 80°C of the cured product within these ranges, the peel strength at elevated temperatures is improved.

[0019] The storage modulus at 120°C of the cured product of the adhesive composition is 10 MPa or more, preferably 50 MPa or more, and more preferably 100 MPa or more. The storage modulus at 80°C of the cured product is preferably 500 MPa or less, more preferably 300 MPa or less, and particularly preferably 250 MPa or less. By having the storage modulus at 120°C of the cured product within these ranges, the peel strength at elevated temperatures is improved.

[0020] The adhesive composition contains a curable component composed of a compound having a polymerizable group. Examples of the curable component include a cationic polymerizable component and a radical polymerizable component. Hereinafter, additives such as curable components and initiators that can be used in the adhesive composition will be exemplified.

[0021] 1. Cationic polymerizable component The adhesive composition contains a cationically polymerizable component. By including a cationically polymerizable component in the adhesive composition, the curing time can be shortened. The cationically polymerizable component is not particularly limited and may be at least one selected from the group consisting of cationically polymerizable monomers, cationically polymerizable oligomers, and cationically polymerizable polymers. Among these, a cationically polymerizable monomer is particularly preferred from the viewpoint of coatability. The number of cationically polymerizable groups in one kind of cationically polymerizable component is not particularly limited and may be a monofunctional cationically polymerizable monomer or a polyfunctional cationically polymerizable monomer. The number of cationically polymerizable groups contained in the cationically polymerizable monomer is preferably 1 to 10, more preferably 2 to 6, for the reason that heat resistance and adhesiveness can be enhanced.

[0022] The content ratio of the cationically polymerizable component in the adhesive composition is preferably 5 to 95% by weight, more preferably 30 to 70% by weight, and particularly preferably 40 to 60% by weight.

[0023] The content ratio of the cationically polymerizable monomer in the cationically polymerizable component is preferably 30% by mass or more, more preferably 50% by mass or more, particularly preferably 70% by mass or more, and may be 100% by mass.

[0024] As the cationically polymerizable monomer, a low-molecular-weight compound is preferred because the viscosity can be reduced. The molecular weight of the cationically polymerizable monomer is preferably 50 to 1500, more preferably 100 to 1000, and particularly preferably 200 to 500.

[0025] The cationically polymerizable monomer that can be used as the cationically polymerizable component is not particularly limited, and examples thereof include epoxy compounds, oxetane compounds, vinyl ether compounds, cyclic ether compounds other than epoxy compounds and oxetane compounds, cyclic acetal compounds, and cyclic imino ether compounds.

[0026] As epoxy compounds, compounds having one epoxy group in the molecule (hereinafter referred to as "monofunctional epoxy compounds") and compounds having two or more epoxy groups in the molecule (hereinafter referred to as "polyfunctional epoxy compounds") can be cited as preferred examples. Examples of epoxy compounds include, for example, compounds having an epoxy group and an aromatic ring skeleton (hereinafter referred to as "aromatic epoxy compounds"), compounds having an alicyclic epoxy group (here, the alicyclic epoxy group represents an alicyclic group that forms an epoxide between two adjacent carbon atoms constituting an aliphatic ring.) (hereinafter referred to as "alicyclic epoxy compounds"), compounds having an epoxy group and not containing an aromatic ring, other than the above "alicyclic epoxy compounds" (hereinafter referred to as "aliphatic epoxy compounds"), and the like. The number of carbon atoms in the aliphatic ring contained in the alicyclic epoxy compound is not particularly limited, but is preferably 3 to 20, more preferably 4 to 10, and particularly preferably 5 to 8. The aliphatic epoxy compound preferably has a linear or branched aliphatic carbon chain. Here, the aliphatic carbon chain is a carbon chain formed only of saturated carbon-carbon bonds. In terms of improving the peel strength, the number of carbon atoms in the aliphatic carbon chain is preferably 3 to 20, more preferably 4 to 15, and particularly preferably 4 to 10. Note that the aliphatic epoxy compound may also contain an aliphatic ring (however, there is no epoxy group between two adjacent carbon atoms constituting the aliphatic ring), similar to the alicyclic epoxy compound.

[0027] Examples of aromatic epoxy compounds include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, rubber-modified bisphenol A diglycidyl ether, bisphenol fluorene or its alkylene oxide adduct di- or polyglycidyl ethers, etc., bisphenol-type epoxy resins; novolak-type epoxy resins such as phenol novolak-type epoxy resins, brominated phenol novolak-type epoxy resins, dicyclopentadiene-phenol novolak-type epoxy resins; naphthalene-type epoxy resins; alkyldiphenol-type epoxy resins; naphthol-type epoxy resins; biphenyl-type epoxy resins; hydroquinone diglycidyl ether; resorcin diglycidyl ether; terephthalic acid diglycidyl ether; phthalic acid diglycidyl ether; N,N,N’,N’-tetraglycidyl-m-xylenediamine and the like.

[0028] Examples of alicyclic epoxy compounds include dicyclopentadiene dioxide, limonene dioxide, 4-vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl) adipate and the like.

[0029] Specific examples of the aliphatic epoxy compound include diglycidyl ethers of alkylene glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol; diglycidyl ethers of neopentyl glycol, dibromoneopentyl glycol, and their alkylene oxide adducts; di- or triglycidyl ethers of trimethylolethane, trimethylolpropane, glycerin, and their alkylene oxide adducts, and polyglycidyl ethers of polyhydric alcohols such as pentaerythritol and its alkylene oxide adducts, di-, tri- or tetraglycidyl ethers; di- or polyglycidyl ethers of hydrogenated bisphenol A and its alkylene oxide adducts; diglycidyl ether of tetrahydrophthalic acid; hydroquinone diglycidyl ether and the like.

[0030] The number of epoxy groups contained in the epoxy compound is preferably 1 to 10, more preferably 2 to 6, for the reason that heat resistance and adhesiveness can be enhanced.

[0031] Only one kind of epoxy compound can be used, or two or more kinds can be used in combination.

[0032] The oxetane compound is not particularly limited as long as it has at least one oxetanyl group in the molecule, and various compounds having an oxetanyl group can be used. As the oxetane compound, compounds having one oxetanyl group in the molecule (hereinafter referred to as "monofunctional oxetane") and compounds having two or more oxetanyl groups in the molecule (hereinafter referred to as "polyfunctional oxetane") are preferably exemplified.

[0033] Preferred examples of the monofunctional oxetane include alkoxyalkyl group-containing monofunctional oxetanes such as 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, aromatic group-containing monofunctional oxetanes such as 3-ethyl-3-phenoxymethyloxetane, hydroxyl group-containing monofunctional oxetanes such as 3-ethyl-3-hydroxymethyloxetane, and the like.

[0034] Examples of the polyfunctional oxetane include the following compounds. 3-Ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane, 1,4-Bis[(3-ethyloxetan-3-yl)methoxymethyl]benzene, 1,4-Bis[(3-ethyloxetan-3-yl)methoxy]benzene, 1,3-Bis[(3-ethyloxetan-3-yl)methoxy]benzene, 1,2-Bis[(3-ethyloxetan-3-yl)methoxy]benzene, 4,4’-Bis[(3-ethyloxetan-3-yl)methoxy]biphenyl, 2,2’-Bis[(3-ethyloxetan-3-yl)methoxy]biphenyl, 3,3’,5,5’-Tetramethyl-4,4’-bis[(3-ethyloxetan-3-yl)methoxy]biphenyl, 2,7-Bis[(3-ethyloxetan-3-yl)methoxy]naphthalene, Bis[4-{(3-ethyloxetan-3-yl)methoxy}phenyl]methane, Bis[2-{(3-ethyloxetan-3-yl)methoxy}phenyl]methane, 2,2-Bis[4-{(3-ethyloxetan-3-yl)methoxy}phenyl]propane, 3(4),8(9)-Bis[(3-ethyloxetan-3-yl)methoxymethyl]-tricyclo[5.2.1.02,6]decane, 2,3-Bis[(3-ethyloxetan-3-yl)methoxymethyl]norbornane, 1,1,1-Tris[(3-ethyloxetan-3-yl)methoxymethyl]propane, 1-Butoxy-2,2-bis[(3-ethyloxetan-3-yl)methoxymethyl]butane, 1,2-Bis[{2-(3-ethyloxetan-3-yl)methoxy}ethylthio]ethane, Bis[{4-(3-ethyloxetan-3-yl)methylthio}phenyl]sulfide, 1,6-bis[(3-ethyloxetan-3-yl)methoxy]-2,2,3,3,4,4,5,5-octafluorohexane and the like.

[0035] From the viewpoints of coatability and adhesion to a substrate, an oxetane compound that is liquid at room temperature and has a molecular weight of 500 or less is preferable. Further, in terms of the cured product having excellent durability, if it is a monofunctional oxetane, an oxetane having an aromatic ring in the molecule, or a polyfunctional oxetane is more preferable. Examples of such particularly preferable oxetane compounds include 3-ethyl-3-phenoxymethyloxetane, 3-ethyl-3-[(3-ethyloxetan-3-yl)methoxymethyl]oxetane, and 1,4-bis[(3-ethyloxetan-3-yl)methoxymethyl]benzene and the like.

[0036] An oxetane compound can be used alone or in combination of two or more.

[0037] Specific examples of the vinyl ether compound include cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, cyclohexanedimethanol divinyl ether and the like.

[0038] The cyclic ether compound other than the epoxy compound and the oxetane compound is not particularly limited, and examples thereof include a compound having a 5- to 10-membered cyclic ether. More specifically, cyclic ether compounds such as tetrahydrofuran and 2,3-dimethyltetrahydrofuran are preferably used.

[0039] The cyclic acetal compound is not particularly limited, and examples thereof include a compound having a 4- to 10-membered cyclic acetal. More specifically, cyclic acetal compounds such as trioxane, 1,3-dioxolane, and 1,3,6-trioxane cyclooctane are preferably used.

[0040] The cyclic imino ether compound is not particularly limited, and examples thereof include compounds having a 4- to 10-membered cyclic imino ether. More specifically, cyclic imino ether compounds such as 2-oxazoline, 1,2-oxazine, and 1,3-oxazine are preferably used.

[0041] Examples of the cationic polymerizable oligomer and the cationic polymerizable polymer include those having a cationic polymerizable group at the terminals of the oligomer and the polymer (for example, hydroxyl-terminated oligomers and polymers such as polyalkylene glycol and polyalkylene polyol, and diglycidyl ethers thereof), and those having a linear structural portion formed by continuously bonding monomer units having a cationic polymerizable group (for example, phenol novolak type epoxy resins, cresol novolak type epoxy resins), and the like.

[0042] The cationic polymerizable component preferably contains an epoxy compound selected from the group consisting of epoxy monomers, epoxy oligomers, and epoxy polymers. The content ratio of the epoxy compound in the cationic polymerizable component is preferably 30% by mass or more, more preferably 50% by mass or more, particularly preferably 70% by mass or more, and may be 100% by mass.

[0043] The cationic polymerizable component preferably contains an aliphatic epoxy compound or an alicyclic epoxy compound. By including an aliphatic epoxy compound or an alicyclic epoxy compound in the adhesive composition, the peel strength can be improved. The total amount of the aliphatic epoxy compound and the alicyclic epoxy compound in the cationic polymerizable component is preferably 30% by mass or more, more preferably 50% by mass or more, particularly preferably 70% by mass or more, and may be 100% by mass.

[0044] 2. Radical polymerizable component The radically polymerizable component is an unsaturated compound having at least one ethylenically unsaturated bond in the molecule. The radically polymerizable component is not particularly limited and may be at least one selected from the group consisting of radically polymerizable monomers, radically polymerizable oligomers, and radically polymerizable polymers. Among these, a radically polymerizable monomer is particularly preferred from the viewpoint of coatability.

[0045] The number of ethylenically unsaturated bonds contained in one kind of radically polymerizable component is preferably 1 to 10, more preferably 2 to 6, because the heat resistance and adhesiveness can be increased.

[0046] The content ratio of the radically polymerizable component in the adhesive composition is preferably 5 to 95% by weight, more preferably 30 to 70% by weight, and particularly preferably 40 to 60% by weight.

[0047] The content ratio of the radically polymerizable monomer in the radically polymerizable component is preferably 30% by weight or more, more preferably 50% by weight or more, particularly preferably 70% by weight or more, and may be 100% by weight.

[0048] As the radically polymerizable monomer, a low molecular weight compound is preferred because the viscosity can be reduced. The molecular weight of the radically polymerizable monomer is preferably 50 to 1500, more preferably 100 to 1000, and particularly preferably 200 to 500.

[0049] Examples of the radically polymerizable monomer include (meth)acrylate compounds having two or more (meth)acryloyl groups in the molecule (hereinafter referred to as polyfunctional (meth)acrylate compounds), (meth)acrylate compounds having one (meth)acryloyl group in the molecule (hereinafter referred to as monofunctional (meth)acrylate compounds), and compounds having an ethylenically unsaturated bond other than the (meth)acryloyl group.

[0050] The polyfunctional (meth)acrylate compound is not particularly limited, and examples thereof include the following compounds.

[0051] Di(meth)acrylates having an aliphatic ring, such as tricyclodecane dimethylol di(meth)acrylate, 1,4-cyclohexane dimethylol di(meth)acrylate, norbornane dimethylol di(meth)acrylate, and di(meth)acrylate of hydrogenated bisphenol A; Di(meth)acrylates having an aromatic ring, such as di(meth)acrylate of bisphenol A ethylene oxide adduct, di(meth)acrylate of bisphenol A propylene oxide adduct including di(meth)acrylate of bisphenol A alkylene oxide adduct, and di(meth)acrylate of bisphenol A diglycidyl ether; Di(meth)acrylates of alkylene glycols, such as ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, pentanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and hexanediol di(meth)acrylate; Di(meth)acrylates of alkylene glycols, such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and dipropylene glycol di(meth)acrylate; Di- or tri-(meth)acrylates of glycerins, such as di- or tri-(meth)acrylate of glycerin, and di- or tri-(meth)acrylate of diglycerin; Di- or tri-(meth)acrylates of alkylene oxide adducts of glycerins; Di(meth)acrylates of bisphenol alkylene oxide adducts, such as di(meth)acrylate of bisphenol A alkylene oxide adduct, and di(meth)acrylate of bisphenol F alkylene oxide adduct; Polyol poly(meth)acrylates such as trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; Poly(meth)acrylates of alkylene oxide adducts of these polyols; Di- or tri(meth)acrylates of alkylene oxide adducts of isocyanuric acid; 1,3,5-tri(meth)acryloylhexahydro-s-triazine and the like.

[0052] Examples of (meth)acrylamides include (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-methylol(meth)acrylamide, N-(3-N,N-dimethylaminopropyl)(meth)acrylamide, methylenebis(meth)acrylamide, ethylenebis(meth)acrylamide and the like.

[0053] The monofunctional (meth)acrylate compounds are not particularly limited, and examples thereof include the following compounds.

[0054] Alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate; Hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; Cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 1,4-cyclohexanedimethanol mono (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, and other alicyclic monofunctional (meth)acrylates; Benzyl (meth)acrylate, (meth)acrylate of p-cumylphenol alkylene oxide adduct, (meth)acrylate of o-phenylphenol alkylene oxide adduct, (meth)acrylate of phenol alkylene oxide adduct, and (meth)acrylate of nonylphenol alkylene oxide adduct, and other monofunctional (meth)acrylates having an aromatic ring (wherein, examples of the alkylene oxide include ethylene oxide, propylene oxide, etc.); 2-methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and (meth)acrylate of alkylene oxide adduct of 2-ethylhexyl alcohol, and other alkoxyalkyl (meth)acrylates; Ethylene glycol mono (meth)acrylate, propylene glycol mono (meth)acrylate, pentanediol mono (meth)acrylate, and hexanediol mono (meth)acrylate, and other monofunctional (meth)acrylates of dihydric alcohols; Mono (meth)acrylate of diethylene glycol, mono (meth)acrylate of triethylene glycol, mono (meth)acrylate of tetraethylene glycol, mono (meth)acrylate of polyethylene glycol, mono (meth)acrylate of dipropylene glycol, mono (meth)acrylate of tripropylene glycol, and mono (meth)acrylate of polypropylene glycol, and other monofunctional (meth)acrylates of polyalkylene glycols; Glycidyl (meth)acrylate; Tetrahydrofurfuryl (meth)acrylate; Tetrahydrofurfuryl (meth)acrylates such as caprolactone-modified tetrahydrofurfuryl (meth)acrylate; 3,4-Epoxycyclohexylmethyl (meth)acrylate; N,N-Dimethylaminoethyl (meth)acrylate; 2-(Meth)acryloyloxyethyl isocyanate, etc.

[0055] Compounds having an ethylenically unsaturated bond other than the (meth)acryloyl group can also be used as a radically polymerizable component. Examples of the compounds having an ethylenically unsaturated bond other than the (meth)acryloyl group include compounds having a vinyl group, compounds having an allyl group, and unsaturated carboxylic acids. Specific examples of the compounds having a vinyl group include 1,4-butanediol divinyl ether, N-vinyl-2-pyrrolidone, divinyl adipate, and divinyl sebacate. Specific examples of the compounds having an allyl group include allyl (meth)acrylate, N,N-diallyl (meth)acrylamide, triallyl isocyanurate, tetraallyl pyromellitate, N,N,N',N'-tetraallyl-1,4-diaminobutane, tetraallyl ammonium salt, and allylamine. Examples of the unsaturated carboxylic acids include maleic acid and itaconic acid.

[0056] In one embodiment, the radically polymerizable monomer preferably has an aliphatic structure. The aliphatic structure is a structure formed from saturated carbon-carbon bonds that do not contain aromatic carbon. For example, the radically polymerizable monomer may be a compound in which an ethylenically unsaturated bond and an aliphatic structure are bonded directly or via a linking group such as O, COO, CO, or OCO. The number of carbon atoms in the aliphatic structure is not particularly limited, but is preferably 3 to 20, more preferably 4 to 15. The aliphatic structure may be linear or branched. The aliphatic structure preferably has an aliphatic ring, and the aliphatic structure may be formed only from aliphatic rings. Although not particularly limited, the radically polymerizable monomer preferably contains 2 to 5 aliphatic rings, more preferably 2 to 3 aliphatic rings. The radically polymerizable monomer may contain a crosslinked condensed ring and may contain a plurality of aliphatic rings within the crosslinked condensed ring. For example, the radically polymerizable monomer may contain two aliphatic rings sharing two or more carbon atoms. The number of carbon atoms in the aliphatic ring is not particularly limited, but is preferably 3 to 20, more preferably 4 to 10.

[0057] In the radically polymerizable monomer, the content of the radically polymerizable monomer having an aliphatic structure is preferably 30% by weight or more, more preferably 50% by weight or more, particularly preferably 70% by weight or more, and may be 100% by weight.

[0058] In the radically polymerizable monomer, the content of the radically polymerizable monomer having an aliphatic ring is preferably 30% by weight or more, more preferably 50% by weight or more, particularly preferably 70% by weight or more, and may be 100% by weight.

[0059] In one embodiment, it is preferable that the radically polymerizable monomer has no reactive group other than the ethylenically unsaturated bond. In particular, it is preferable that the radically polymerizable monomer does not contain a hydroxyl group or a phosphate group. In the radically polymerizable monomer, the content ratio of the radically polymerizable monomer having a reactive group selected from the group consisting of a hydroxyl group and a phosphate group is preferably 30% by weight or less, more preferably 20% by weight or less, particularly preferably 10% by weight or less, and may be 0% by weight.

[0060] Examples of the cationically polymerizable oligomer and the radically polymerizable polymer include those having an ethylenically unsaturated bond at the terminals of the oligomer and the polymer, particularly those having an acryloyl group at the terminals of the oligomer and the polymer (for example, urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate).

[0061] The weight ratio (cationically polymerizable component / radically polymerizable component) of the cationically polymerizable component and the radically polymerizable component in the adhesive composition is preferably 5 / 95 to 95 / 5, more preferably 30 / 70 to 70 / 30, and particularly preferably 40 / 60 to 60 / 40.

[0062] The total content of the cationically polymerizable component and the radically polymerizable component in the adhesive composition is preferably 60% by weight or more, more preferably 70% by weight or more, and particularly preferably 80% by weight or more. The upper limit of the total content of the cationically polymerizable component and the radically polymerizable component in the adhesive composition is not particularly limited, but the total content may be, for example, 99.9% by weight or less.

[0063] 3. Other Components Furthermore, other components different from the above components can be arbitrarily blended in the adhesive composition as long as the effects of the present invention are not impaired.

[0064] The adhesive composition may contain a polyfunctional isocyanate compound. By including an isocyanate compound in the adhesive composition, the peel strength can be improved. Furthermore, the solvent resistance of the adhesive composition can be improved by the isocyanate compound. For example, even after contact with an electrolyte solvent such as ethylene carbonate or diethylene carbonate, the adhesive composition containing the isocyanate compound can maintain a higher peel strength.

[0065] The isocyanate compound may be a monofunctional isocyanate compound or a polyfunctional isocyanate compound. That is, in the present invention, the number of isocyanate groups contained in the isocyanate compound is not particularly limited. A polyfunctional isocyanate compound is a compound having two or more isocyanate groups, and particularly preferably a compound having two isocyanate groups.

[0066] The isocyanate compound is not particularly limited, and various isocyanate compounds of aromatic, aliphatic, and alicyclic types can be used. Examples of the monofunctional isocyanate compound include ethyl isocyanate, propyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, and the like. Examples of the polyfunctional isocyanate compound include pentamethylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornane diisocyanate, and the like.

[0067] In this specification, unless otherwise specified, the term "isocyanate compound" includes derivatives formed from isocyanate compounds in addition to isocyanate compounds. Derivatives of isocyanate compounds are compounds in which the isocyanate group has been changed by a chemical reaction to an isocyanurate bond, a biuret bond, a urethane bond, an allophanate bond, a urea bond, a uretdione bond, or the like. Compounds containing an isocyanurate bond are particularly preferred in that they have a high effect of improving adhesion to a substrate and can improve the peel strength at room temperature and the electrolyte resistance. The number of isocyanate groups contained in the derivative is at least 1 or more, and derivatives in which two or more isocyanate groups are retained unreacted are particularly preferred.

[0068] Derivatives may be formed from two or more of the same or different isocyanate compounds. Specific examples of such derivatives of isocyanate compounds include multimers of polyfunctional isocyanate compounds. Multimers of isocyanate compounds may be formed via the bonds listed above, such as uretdione bonds, isocyanurate bonds, allophanate bonds, etc. The isocyanate compounds forming the multimer are usually all of the same type of isocyanate compound, but may also be different types of isocyanate compounds. Using multimers formed from different types of isocyanate compounds may improve the peel strength of the adhesive composition in some cases. The number of isocyanate compounds constituting the multimer is not particularly limited and may be a general multimer of an isocyanate compound. Specifically, the multimer may be a dimer, trimer, or tetramer formed from a polyfunctional isocyanate compound, etc.

[0069] When present, the total amount of the isocyanate compound and its derivatives in the adhesive composition is preferably 1 to 40% by weight, more preferably 2 to 20% by weight, and particularly preferably 3 to 8% by weight.

[0070] The adhesive composition may contain a polymerization initiator. Since the polymerizable compound can initiate polymerization even without the presence of a polymerization initiator depending on the curing means such as active energy rays to be applied, the polymerization initiator is an optional component, and the adhesive composition may not contain a polymerization initiator.

[0071] The polymerization initiator can be selected from the group consisting of a photo cationic polymerization initiator, a thermal cationic polymerization initiator, and a photo radical polymerization initiator.

[0072] The photo cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates the polymerization reaction of cationically polymerizable components such as epoxy groups and oxetanyl groups.

[0073] By blending a photo cationic polymerization initiator, curing at room temperature becomes possible, and good adhesion between metal and resin can be achieved. Also, since the photo cationic polymerization initiator acts catalytically upon irradiation with active energy rays, it has excellent storage stability and workability even when mixed with the cationically polymerizable component. Examples of photo cationic polymerization initiators that generate cationic species or Lewis acids upon irradiation with active energy rays include onium salts such as aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts, and iron-allyl complexes.

[0074] Examples of aromatic diazonium salts include the following compounds. Benzene diazonium hexafluoroantimonate, Benzene diazonium hexafluorophosphate, Benzene diazonium hexafluoroborate, etc.

[0075] Examples of aromatic iodonium salts include the following compounds. Diphenyliodonium tetrakis(pentafluorophenyl)borate, Diphenyliodonium hexafluorophosphate, Diphenyliodonium hexafluoroantimonate, Di(4-nonylphenyl)iodonium hexafluorophosphate and the like.

[0076] Examples of the aromatic sulfonium salts include the following compounds. Triphenylsulfonium hexafluorophosphate, Triphenylsulfonium hexafluoroantimonate, Triphenylsulfonium tetrakis(pentafluorophenyl)borate, Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate, Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate, 4,4'-Bis(diphenylsulfonio)diphenyl sulfide bishexafluorophosphate, 4,4'-Bis[di(β-hydroxyethoxy)phenylsulfonio]diphenyl sulfide bishexafluoroantimonate, 4,4'-Bis[di(β-hydroxyethoxy)phenylsulfonio]diphenyl sulfide bishexafluorophosphate, 7-[Di(p-tolyl)sulfonio]-2-isopropylthioxanthone hexafluoroantimonate, 7-[Di(p-tolyl)sulfonio]-2-isopropylthioxanthone tetrakis(pentafluorophenyl)borate, 4-Phenylcarbonyl-4'-diphenylsulfonio-diphenyl sulfide hexafluorophosphate, 4-(p-tert-Butylphenylcarbonyl)-4'-diphenylsulfonio-diphenyl sulfide hexafluoroantimonate, 4-(p-tert-Butylphenylcarbonyl)-4'-di(p-tolyl)sulfonio-diphenyl sulfide tetrakis(pentafluorophenyl)borate and the like.

[0077] Examples of the iron-arene complexes include the following compounds. Xylene-cyclopentadienyliron(II) hexafluoroantimonate, Cumene-cyclopentadienyliron(II) hexafluorophosphate, Xylene-cyclopentadienyliron(II)-tris(trifluoromethylsulfonyl)methanide, etc.

[0078] These photo cationic polymerization initiators may be used individually, one type at a time, or in combination of two or more types. Among these, aromatic sulfonium salts are particularly preferred because they have ultraviolet absorption characteristics even in the wavelength region of 300 nm or more, are excellent in curability, and can provide a cured product having good mechanical strength and adhesive strength.

[0079] Photo cationic polymerization initiators can be easily obtained as commercial products. For example, under their respective trade names, there are "Kayrad PCI-220", "Kayrad PCI-620" (both manufactured by Nippon Kayaku Co., Ltd.), "UVI-6992" (manufactured by Dow Chemical Company), "Adeka Optomer SP-150", "Adeka Optomer SP-170" (both manufactured by ADEKA Corporation), "CI-5102", "CIT-1370", "CIT-1682", "CIP-1866S", "CIP-2048S", "CIP-2064S" (all manufactured by Nippon Soda Co., Ltd.), "DPI-101", "DPI-102", "DPI-103", "DPI-105", "MPI-103", "MPI-105", "BBI-101", "BBI-102", "BBI-103", "BBI-105", "TPS-101", "TPS-102", "TPS-103", "TPS-105", "MDS-103", "MDS-105", "DTS-102", "DTS-103" (all manufactured by Midori Chemical Co., Ltd.), "PI-2074" (manufactured by Rhodia), "Irgacure 250", "Irgacure PAG103", "Irgacure PAG108", "Irgacure PAG121", "Irgacure PAG203" (all manufactured by Ciba), "CPI-100P", "CPI-101A", "CPI-200K", "CPI-210S" (all manufactured by San-Apro Ltd.), etc. Particularly preferred are "UVI-6992" manufactured by Dow Chemical Company, "CPI-100P", "CPI-101A", "CPI-200K", "CPI-210S" manufactured by San-Apro Ltd., which contain diphenyl [4-(phenylthio)phenyl] sulfonium as the cation component.

[0080] Photo radical polymerization initiators generate radical species upon irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiate the polymerization reaction of radically polymerizable compounds.

[0081] Specific examples of photo radical polymerization initiators are not particularly limited, but for example, the following compounds can be mentioned.

[0082] Acetophenone-based photoinitiators such as 4'-phenoxy-2,2-dichloroacetophenone, 4'-tert-butyl-2,2-dichloroacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 1-hydroxycyclohexyl phenyl ketone, α,α-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methylpropan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one; Benzoin ether-based photoinitiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; Benzophenone-based photoinitiators such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 2,4,6-trimethylbenzophenone; Thioxanthone-based photoinitiators such as 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propoxythioxanthone; Acylphosphine oxide-based photoinitiators such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide; Oxime ester-based photoinitiators such as 1,2-octanedione, 1-[4-(phenylthiophenyl)]-, 2-(O-benzoyloxime); Camphorquinone and the like.

[0083] A thermal cationic polymerization initiator is activated by heating and induces ring-opening polymerization of cationic polymerizable groups contained in cationic polymerizable compounds such as epoxy compounds and oxetane compounds. Examples of the thermal cationic polymerization initiator include benzylsulfonium salts, thiophenium salts, thianium salts, benzylammonium salts, pyridinium salts, hydrazinium salts, carboxylic acid esters, sulfonic acid esters, amine imides, and the like. These thermal cationic polymerization initiators can be easily obtained as commercial products. For example, all of them are indicated by their trade names, such as "Adeka Opton CP77" and "Adeka Opton CP66" (both manufactured by ADEKA CORPORATION), "CI-2639" and "CI-2624" (both manufactured by Nippon Soda Co., Ltd.), "Sun-Aid SI-60L", "Sun-Aid SI-80L", and "Sun-Aid SI-100L" (all manufactured by Sanshin Chemical Industry Co., Ltd.).

[0084] The polymerization initiator can be used alone or in combination of two or more types according to the desired performance. When present, the content of the polymerization initiator in the adhesive composition is preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight, and particularly preferably 1 to 3% by weight.

[0085] Different types of initiators may be used in combination. For example, the peel strength of the adhesive composition may be improved by using a photo cationic polymerization initiator and a photo radical polymerization initiator in combination.

[0086] Examples of components belonging to other components include water and hydroxy group-containing compounds such as alcohol. As the alcohol, compounds having a plurality of hydroxy groups are preferred, and for example, compounds having 2 to 4 hydroxy groups can be preferably used. Specific examples of the alcohol include aliphatic alcohols having 2 to 6 carbon atoms such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, and glycerin. By adding a small amount of the hydroxy group-containing compound to the adhesive composition, the reactivity of the isocyanate compound can be controlled, and a cured product having high adhesive performance can be obtained even under drying conditions. From the viewpoint of improving the electrolyte resistance, water is particularly preferred as the hydroxy group-containing compound. When present, the content of the hydroxy group-containing compound in the adhesive composition is preferably 0.05 to 5% by weight, more preferably 0.5 to 4% by weight, and particularly preferably 0.8 to 3% by weight. The water content in the adhesive composition can be measured by the Karl Fischer titration method in accordance with JIS K 0113 (2005).

[0087] Another type belonging to other components includes a photosensitizer. By blending a photosensitizer, the reactivity can be improved, and the mechanical strength and adhesive strength of the cured product can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreductive dyes, and the like.

[0088] Specific photosensitizers are not particularly limited, and examples include the following compounds. Benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and α,α-dimethoxy-α-phenylacetophenone; Benzophenone derivatives such as benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis(dimethylamino)benzophenone, and 4,4'-bis(diethylamino)benzophenone; Thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; Anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone; Acridone derivatives such as N-methylacridone and N-butylacridone; Others, such as α,α-diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compounds, halogen compounds, etc.

[0089] The photosensitizer functions as a sensitizer for a cationic photopolymerization initiator or a radical photopolymerization initiator and can be appropriately selected and used according to the polymerization initiator contained in the adhesive composition. These may be used alone or in combination of two or more.

[0090] The photosensitizer is preferably contained in the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the total amount of the cationically polymerizable components in the adhesive composition.

[0091] Polyols have the property of promoting cationic polymerization and can be incorporated into the adhesive composition. As polyols, those having no acidic groups other than phenolic hydroxyl groups are preferred, and examples include polyol compounds having no functional groups other than hydroxyl groups, polyester polyol compounds, polycaprolactone polyol compounds, polyol compounds having phenolic hydroxyl groups, polycarbonate polyol compounds, and the like.

[0092] Furthermore, as long as the effects of the present invention are not impaired, a silane coupling agent, an ion trap agent, an antioxidant, a light stabilizer, a chain transfer agent, a sensitizer, a tackifier, a thermoplastic resin, a filler, a flow regulator, a plasticizer, an antifoaming agent, a leveling agent, a pigment, a solvent, etc. can also be incorporated.

[0093] In this embodiment, it is preferable that the contents of oligomers and polymers are reduced. By reducing the contents of oligomers and polymers such as polyolefins and polyurethanes, it becomes possible to easily apply the adhesive composition. The total content of monomers in the adhesive composition is preferably 60% by weight or more, more preferably 80% by weight or more, particularly preferably 90% by weight or more, and may be 100% by weight.

[0094] In this embodiment, it is preferable that the content of the solvent in the adhesive composition is reduced. Here, the solvent is a volatile component other than the curable component described above, and is not particularly limited, but the boiling point of the solvent may be, for example, 120°C or lower. The content of the solvent in the adhesive composition is preferably 30% by weight or less, more preferably 20% by weight or less, particularly preferably 10% by weight or less, and the adhesive composition may not contain a solvent.

[0095] 4. Curable Adhesive Composition As a method for producing the adhesive composition, the above-described components can be mixed, and if necessary, other components can be further mixed, and the mixture can be produced by stirring according to a conventional method. In this case, heating can also be performed if necessary. The heating temperature may be appropriately set according to the adhesive composition, substrate, purpose, etc. used, but 30 to 80°C is preferable.

[0096] The viscosity of the adhesive composition at 25°C is preferably 10 to 1,000 mPa·s in terms of excellent coatability on the substrate.

[0097] 5. Usage Method The adhesive composition of the present invention can be used for bonding different materials such as metal and resin. Specific examples of the usage method include a method in which after applying to a substrate, it is bonded to the other substrate, and the adhesive composition is cured by irradiation with active energy rays or heating. Thus, the adhesive composition may be an active energy ray curable type or a heat curable type, but is particularly preferably an active energy ray curable type.

[0098] The resin is not particularly limited. For example, hydrophilic resins such as polyvinyl alcohol and cellulose ester; and hydrophobic resins such as polycarbonate, polyethylene terephthalate, polyethylene naphthalate, acrylic, acrylic / styrene, aliphatic polyamide (nylon), aromatic polyamide, polyarylate, polyethersulfone, polyurethane, polyimide, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyolefin (e.g., polyethylene, polypropylene, propylene-butene copolymer, etc.), polycycloolefin, polystyrene, and ABS resin. The resin to be adhered is preferably processed into a film, and particularly preferably an unstretched resin film.

[0099] Specific examples of the metal include gold, silver, copper, aluminum, iron, nickel, titanium, stainless steel, and chromium molybdenum steel. The metal to be adhered is preferably processed into a metal plate, a metal flat plate, or a metal foil.

[0100] Coating on the substrate may be carried out according to a conventionally known method, and examples of the method include a natural coater, a knife belt coater, a floating knife, a knife over roll, a knife on blanket, spray, dip, kiss roll, squeeze roll, reverse roll, air blade, curtain flow coater, comma coater, gravure coater, microgravure coater, die coater, and curtain coater. In addition, the coating thickness of the adhesive composition of the present invention may be selected according to the substrate and application to be used, but is preferably 0.1 to 100 μm, more preferably 1 to 25 μm.

[0101] Examples of the active energy ray include visible light, ultraviolet ray, X-ray, and electron beam. Since an inexpensive device can be used, ultraviolet ray is preferable.

[0102] As the light source for curing by ultraviolet rays, various ones can be used. For example, a pressurized or high-pressure mercury lamp, a metal halide lamp, a xenon lamp, an electrodeless discharge lamp, a carbon arc lamp, an LED, etc. can be mentioned. Among these, a high-pressure mercury lamp and a metal halide lamp are preferable, and a metal halide lamp is particularly preferable. The irradiation amount of ultraviolet rays is preferably 200 to 2,000 mJ / cm 2 in the UV-A region (near 365 nm), and more preferably 300 to 1,500 mJ / cm 2 .

[0103] When curing by electron beam, various devices can be used as the electron beam irradiation device. For example, a Cockcroft-Walton type, a Van de Graaff type, a resonant transformer type device, etc. can be mentioned. As the absorbed dose of the electron beam, 1 to 200 kGy is preferable, and 10 to 100 kGy is more preferable. As the acceleration voltage of the electron beam, it can be appropriately set in the range of 80 to 300 kV according to the film thickness of the substrate. For example, when the film thickness of the substrate is 100 μm, 200 kV is preferable. As the oxygen concentration in the electron beam irradiation atmosphere, 500 ppm or less is preferable, and 300 ppm or less is more preferable.

[0104] 6. Heat-sealable member A heat-sealable member can be manufactured using the adhesive composition. The heat-sealable member of the present invention includes an adhesive layer formed by curing the adhesive composition of the present invention, a metal layer joined to one surface side of the adhesive layer, and a heat-sealable resin layer joined to the other surface side of the adhesive layer.

[0105] A schematic view of the heat-sealable member is shown in FIGS. 1 and 2. That is, the heat-sealable member 1 in FIG. 1 sequentially includes a heat-sealable resin layer 11, an adhesive layer 12, and a metal layer 13. Further, the heat-sealable member 1 in FIG. 2 sequentially includes a heat-sealable resin layer 11, an adhesive layer 12, a metal layer 13, and another layer 14.

[0106] The shape of the heat-sealable member may be appropriately set according to the use, etc., and is not particularly limited, but examples include a film shape, a sheet shape, a plate shape, etc.

[0107] The above-mentioned heat-sealable resin layer is a layer containing a resin that can be melted by heat and fuse the material constituting the layer on one side and the material constituting the layer on the other side. And this heat-sealable resin layer is preferably a layer containing a resin that melts at a temperature of 50°C to 200°C. Examples of resins having such properties include polyolefin resins, polyamide resins, and polyester resins. Among these, polyolefin resins are preferred because they can be heat-sealed with sufficient strength. Further, as the polyolefin resin, polyethylene and polypropylene are preferred. In particular, when using a heat-sealable member to integrate with other members, since there is little dimensional change (shrinkage), it is preferably a non-stretched resin, and non-stretched polyethylene and non-stretched polypropylene are more preferred.

[0108] The above-mentioned heat-sealable resin layer may, if necessary, be a layer containing additives such as lubricants, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, colorants, dispersants, and adhesion promoters.

[0109] The thickness of the above-mentioned heat-sealable resin layer is not particularly limited and depends on the material of the resin, etc. For example, when it is a layer containing non-stretched polypropylene, it is preferably 10 μm to 200 μm, more preferably 20 μm to 100 μm. If the thickness of the layer containing non-stretched polypropylene is 10 μm to 200 μm, it will not be easily damaged, and a heat-sealed composite product such as a highly durable sealed container can be obtained.

[0110] The above-mentioned adhesive layer is a layer formed by curing an adhesive composition. The thickness of the adhesive layer is not particularly limited, but is preferably 1 μm to 20 μm, particularly preferably 2 μm to 10 μm. If the thickness of the adhesive layer is 1 μm to 20 μm, processing such as bending is easy when the heat-sealable member is, for example, in the form of a sheet.

[0111] The above metal layer is a layer containing a metal or an alloy. Examples of the metal or alloy include aluminum, iron, titanium, magnesium, copper, nickel, chromium, and other metals, as well as their alloys. Among these, aluminum is preferred because of its excellent workability. The thickness of the metal layer is not particularly limited and depends on its material and other factors. When the metal layer is made of aluminum, for example, it is preferably 20 μm to 100 μm, more preferably 20 μm to 80 μm, and particularly preferably 30 μm to 60 μm.

[0112] When the heat-sealable member includes a metal layer, as shown in FIG. 2, another layer 14 can be provided on the surface of the metal layer 13. From the perspective of protecting the metal layer, the material constituting the other layer preferably contains a resin. That is, the other layer is preferably a resin layer. This resin is not particularly limited and can be a polyamide resin, a polyester resin, or the like. The transparency of the resin layer is not particularly limited, but when this resin layer is transparent or translucent, an excellent appearance can be obtained when the heat-sealed composite product is used as a sealed container or the like. The other layer may have a multilayer structure. For example, it may include an adhesive layer for bonding the resin layer and the metal layer. The adhesive layer in the other layer may be the same as or different from the adhesive layer provided between the heat-sealable resin layer and the metal layer. The thickness of the other layer is not particularly limited and is preferably 30 μm to 60 μm, and particularly preferably 30 μm to 50 μm.

[0113] When the heat-sealable member is used as a lithium-ion battery packaging material, the adhesive performance can be maintained even in the presence of temperature changes in the battery storage or usage environment. In particular, the adhesive performance can be maintained in the chemical temperature rise of the battery constituent materials accompanying charging or discharging, in a temperature range higher than the normal temperature in summer or inside a vehicle, and in a temperature range lower than the outside air temperature in cold regions.

[0114] The manufacturing method of the heat-sealable member shown in FIG. 1 is as follows. (1) Apply the adhesive composition onto the surface of a metal foil or the like for forming the metal layer 13 to form the adhesive layer 12. Then, bring a resin film for forming the heat-sealable resin layer 11 (hereinafter referred to as "heat-sealable resin film") into contact with the surface on which the adhesive layer 12 is formed, press-bond them, and irradiate with active energy rays.

[0115] (2) Apply the adhesive composition onto the surface of the heat-sealable resin film to form the adhesive layer 12. Then, bring a metal foil or the like for forming the metal layer 13 into contact with the surface on which the adhesive layer 12 is formed, press-bond them, and irradiate with active energy rays.

[0116] Also, the method for manufacturing the heat-sealable member shown in FIG. 2 is as follows. (3) Apply the adhesive composition onto the surface of the metal layer 13 in a composite film having a resin layer constituting the other layer 14 and a metal layer 13 formed by lamination, vapor deposition, or the like on one side of this resin layer to form the adhesive layer 12. Then, bring the surface on which the adhesive layer 12 is formed into contact with the heat-sealable resin film, press-bond them, and irradiate with active energy rays.

[0117] (4) Apply the adhesive composition onto the surface of the heat-sealable resin film to form the adhesive layer 12. Then, bring the surface on which the adhesive layer 12 is formed into contact with the surface on which the metal layer 13 is formed in a composite film having a resin layer constituting the other layer 14 and a metal layer 13 formed by lamination, vapor deposition, or the like on one side of this resin layer, press-bond them, and irradiate with active energy rays.

[0118] (5) A method of extrusion-molding a film for forming the other layer 14 onto the surface of the metal layer 13 in the laminate obtained by the method of (1) or (2) above.

[0119] The adhesive composition is often applied to a material for forming a metal layer such as a metal foil, or to the surface of the metal layer in a composite film including a metal layer and another layer (resin layer), but is not particularly limited. When using a metal foil, it is preferable to use an aluminum foil with a thickness of 20 μm to 100 μm. Thereby, a heat-sealable member with suppressed breakage can be easily formed. When using a composite film, it is preferable that the metal layer contains aluminum and the other layer (resin layer) contains a polyamide resin, a polyester resin, etc. Further, when manufacturing the heat-sealable member shown in FIG. 2 without using a composite film, that is, when adopting the method of (5) above, it is preferable to use a film containing a polyamide resin, a polyester resin, etc. as the film for forming the other layer 14.

[0120] As the heat-sealable resin film, a polyolefin resin film, a polyamide resin film, a polyester resin film, etc. can be used. These resin films can be films obtained by a film-forming method such as an extrusion method, a cast molding method, a T-die method, and an inflation method. The thickness of the heat-sealable resin film is usually 10 to 200 μm.

[0121] 7. Packaging Material for Energy Storage Devices The heat-sealable member can be used in various industrial product fields in the electrical field, automotive field, industrial field, and other fields. As the use of the heat-sealable member, since it has a high hot peel strength, excellent adhesiveness, and high electrolyte resistance, a packaging material for energy storage devices is particularly preferable. Examples of the energy storage device for which the packaging material for energy storage devices is used include secondary batteries such as lithium-ion batteries and lithium-ion polymer batteries.

Examples

[0122] Hereinafter, examples and comparative examples will be shown to more specifically explain the present invention, but the present invention is not limited by these examples.

[0123] (Preparation of Adhesive Composition) In each example, the respective components shown in the following table were blended in the amounts described in the table, and stirred and mixed to prepare an adhesive composition. The details of the abbreviations described in the table are as follows. The amounts of each component in the table represent weight ratios. <Cationic polymerizable component> · Epoxy Go-Say BD: 1,4-butanediol diglycidyl ether, "Epoxy Go-Say BD (D)" manufactured by Yokkaichi Gosei Co., Ltd. · Epoxy Go-Say HD: 1,6-hexanediol diglycidyl ether, "Epoxy Go-Say HD" manufactured by Yokkaichi Gosei Co., Ltd. · jER1004: Polycondensate (solid) of 4,4'-isopropylidenediphenol and 1-chloro-2,3-epoxypropane, "jER1004" manufactured by Mitsubishi Chemical Corporation · Celoxide 2021P: 3,4-Epoxycyclohexylmethyl (3,4-epoxy) cyclohexanecarboxylate, "Celoxide 2021P" manufactured by Daicel Corporation · R-45EPT: Polybutadiene diglycidyl ether, "Denarex R-45EPT" manufactured by Nagase ChemteX Corporation · OXT-221: 3-Ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane, "Aronix (registered trademark) OXT-221" manufactured by Toagosei Co., Ltd. · EXA-850CRP: Bisphenol A diglycidyl ether, "Epiclon EXA-850CRP" manufactured by DIC Corporation <Radical polymerizable component> · Light Acrylate DCP-A: Tricyclodecane dimethylol diacrylate, "Light Acrylate DCP-A" manufactured by Kyoeisha Chemical Co., Ltd. · Biscoat 190: Ethyl carbitol acrylate, "Biscoat 190" manufactured by Osaka Organic Chemical Industry Co., Ltd. · Aronix OT-1001: 50 wt% diluted product of isobornyl acrylate (hereinafter referred to as "IBXA") of non-yellowing polyester skeleton urethane acrylate (Mw 40,000), "Aronix (registered trademark) OT-1001" manufactured by Toagosei Co., Ltd. · HPA: 2-Hydroxypropyl acrylate, "Light Ester HOP-A" manufactured by Kyoeisha Chemical Co., Ltd. · 4HBA: 4-Hydroxybutyl acrylate, "Biscoat 4-HBA" manufactured by Osaka Organic Chemical Industry Co., Ltd. · ACMO: Acryloylmorpholine, "ACMO" manufactured by KJ Chemicals Co., Ltd. <Other components> · BHT: 2,6-Di-tert-butyl-p-cresol, "BHT" manufactured by JGC Universal Co., Ltd. · CPI-110P: Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate, "CPI-110P" manufactured by San-Apro Ltd. · Omnirad184D: 1-Hydroxycyclohexyl phenyl ketone, "Omnirad184D" manufactured by IGM Resins · OmniradTPO: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, "OmniradTPO" manufactured by IGM Resins · Irgacure 250: 4-Isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate, "Irgacure 250" manufactured by BASF · DETX-S: 2,4-Diethylthioxanthone, "DETX-S" manufactured by Nippon Kayaku Co., Ltd. · TPA-100: Polyisocyanate of hexamethylene diisocyanate, "Duranate TPA-100" manufactured by Asahi Kasei Co., Ltd. · CM03: 2-Hydroxy-3-(methacryloyloxy)propyl-3,4-dihydroxybenzoate, "CM03" manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0124] (Preparation of test pieces for peel strength evaluation) An adhesive composition was applied to the surface of an aluminum foil that had been subjected to a chemical conversion treatment with a thickness of 40 μm, and a corona discharge treatment was performed on a 80-μm-thick CPP (cast polypropylene) film. The corona discharge-treated surface of the CPP film was overlapped with the adhesive-coated surface facing each other. The laminated film was sandwiched between two sheets of copy paper, top and bottom, and passed through a room-temperature roll laminator so that the average thickness of the adhesive was 2 μm to 4 μm. When measuring the peel strength to be performed later, the part to be clamped by the gripping tool of the tensile testing machine was not coated with the adhesive. The laminated film was taken out, and then, from the CPP film side of the laminated film, ultraviolet irradiation was performed using a conveyor-type ultraviolet irradiation device (high-pressure mercury lamp, irradiation intensity in the UV-A region of 280 mW / cm 2 , integrated light quantity of 600 mJ / cm 2 , both measured values of UV POWER PUCK II manufactured by Heraeus Co., Ltd.), and the adhesive composition was cured to prepare test pieces. The next day, it was cut into strips with a width of 15 mm to obtain test pieces for peel strength evaluation.

[0125] (Measurement of peel strength) Using a tensile testing machine with a thermostat (Autograph AGS-X manufactured by Shimadzu Corporation), a T-peel test was conducted at a pulling speed of 100 mm / min until the gripping tool moved 100 mm. The peel strength from a moving distance of 40 mm to 100 mm was averaged to obtain the peel strength (N / 15 mm). The peel test was performed at two temperatures: 80°C and 120°C.

[0126] (Measurement of storage modulus) The storage modulus of the adhesive composition was measured by the following method. A cycloolefin polymer film (0.1 mm t × 100 mm × 150 mm, ZF-14-100 manufactured by Nippon Zeon Co., Ltd.) and a silicone rubber (0.5 mm t × 90 mm × 140 mm) cut out in a size of 5 × 50 mm were placed in order on a glass plate (1.6 mm t × 120 mm × 170 mm). The cut-out part was filled with the adhesive composition and sandwiched with a cycloolefin polymer film of the same size so that no bubbles were introduced. Further, with a glass plate of the same size placed on top, the four sides were clamped with clips and fixed. Using a high-pressure mercury lamp, 50 mW / cm 2The UV on one side was irradiated for 30 seconds each to temporarily cure the adhesive. Next, the temporarily cured product of the adhesive was taken out of the mold, and the UV of 50 mW / cm 2 was directly irradiated on the front and back for 2 minutes each to cure the adhesive, and burrs were removed to obtain strip-shaped test pieces of 0.5 mm t × 5 mm × 50 mm. The test pieces were left in an environment of 23°C × 55% RH for more than 24 hours for conditioning and then used for the measurement of dynamic viscoelasticity. Using DMS6100 manufactured by Hitachi High-Technologies Corporation, the temperature was measured from at least -20°C to 130°C at a heating rate of 2°C / min and a frequency of 1 Hz, and the storage modulus (E') at 80°C and 120°C was confirmed.

[0127]

Table 1

[0128] In the examples using the adhesive composition with a storage modulus of 100 MPa or more at 80°C, the peel strength was higher at both 80°C and 120°C than in the comparative examples.

Claims

1. A curable adhesive composition for bonding a metal and a resin, comprising at least one cationic polymerizable component selected from the group consisting of a cationic polymerizable monomer, a cationic polymerizable oligomer, and a cationic polymerizable polymer, The curable adhesive composition, wherein the storage elastic modulus of the cured product of the composition at 80 ° C is 100 MPa or more.

2. The curable adhesive composition according to claim 1, wherein the storage elastic modulus of the cured product of the composition at 120 ° C is 10 MPa or more.

3. The curable adhesive composition according to claim 1 or 2, further comprising at least one radical polymerizable component selected from the group consisting of a radical polymerizable monomer, a radical polymerizable oligomer, and a radical polymerizable polymer.

4. The curable adhesive composition according to claim 3, comprising 40% by mass or more and 80% by mass or less of the radical polymerizable component.

5. The curable adhesive composition according to claim 3, wherein the radical polymerizable component is an alicyclic polyfunctional acrylate.

6. The curable adhesive composition according to claim 1 or 2, wherein the resin is a polyolefin.

7. The curable adhesive composition according to claim 1 or 2, which is an active energy ray curable adhesive composition.

8. The curable adhesive composition according to claim 1 or 2, which is an adhesive composition for a power storage device packaging material.

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