WO2024135755A1 - Curable adhesive agent composition - Google Patents

Abstract

A curable adhesive agent composition according to the present invention is for the adhesion of a metal and a resin and is characterized in that the curable adhesive agent composition contains (1) a cation-polymerizable component containing a cation-polymerizable monomer and (2) a radical-polymerizable component containing a radical-polymerizable monomer, and the cation-polymerizable component includes an epoxy monomer having two or more epoxy groups.

Description

Curable adhesive composition

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

　General packaging materials for power storage devices used in laminated batteries have a three-layer structure with metal foil at the center, and adhesive is used between each layer. The three layers are the base layer that becomes the outside of the battery after the laminated battery is formed, the barrier layer that is made of metal foil such as aluminum foil or stainless steel foil and prevents the penetration of moisture and air, and the sealant layer that serves the purpose of insulating the barrier layer from contact with the electrodes and electrolyte and of heat fusing the outer periphery to bond them together, and each layer may be formed in two or more layers. Of these, a polyolefin resin film such as polypropylene film is usually used for the sealant layer that comes into contact with the electrolyte.

An adhesive containing an acid-modified polyolefin and a crosslinking agent is generally used to bond the sealant layer and the metal foil. For example, Patent Document 1 describes an adhesive composition for lamination that contains a modified polyolefin resin (A), an alcohol-based epoxy compound (B), and a polyfunctional isocyanate compound (C). Also, for example, Patent Document 2 describes an exterior material for a storage battery device in which the 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.

JP 2015-059200 A JP 2017-201580 A

Adhesives based on acid-modified polyolefins are often used to bond adherends made of different materials, such as metal and resin, such as adhesives used in packaging materials for energy storage devices. However, adhesives based on acid-modified polyolefins also have issues that need to be addressed.

The adhesive described in Patent Document 1 had the problem that it took a long time to harden, and an aging process of several days was required to achieve high adhesive strength.

The adhesive described in Patent Document 2 is capable of bonding without an aging step, and can shorten the bonding time compared to the adhesive in 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 in order to be applied to the adherend, and a drying step must be provided to remove the solvent after application. To further shorten the bonding process, it is necessary to develop a new adhesive that uses less solvent.

On the other hand, the adhesive must also be able to maintain high peel strength even at high temperatures in preparation for heat generation caused by abnormal conditions in the battery, a performance that has traditionally been required of adhesives used in packaging materials for energy storage devices.

The objective of one embodiment of the present invention is to provide a curable adhesive composition for bonding metals and resins that can shorten the bonding process and maintain high peel strength even at high temperatures.

Means for solving the above problems include the following aspects.
<1> A curable adhesive composition for bonding metal and resin, the curable adhesive composition comprising: (1) a cationically polymerizable component containing a cationically polymerizable monomer; and (2) a radically polymerizable component containing a radically polymerizable monomer, the cationically polymerizable component comprising an epoxy monomer having two or more epoxy groups.
<2> The curable adhesive composition according to <1>, wherein the epoxy monomer comprises at least one epoxy monomer selected from the group consisting of aliphatic epoxy monomers and alicyclic epoxy monomers.
<3> The curable adhesive composition according to <1> or <2>, wherein the epoxy monomer includes an aliphatic epoxy monomer, and the aliphatic epoxy monomer has an aliphatic carbon chain having 3 to 20 carbon atoms.
<4> The curable adhesive composition according to any one of <1> to <3>, wherein the total content of the cationically polymerizable component and the radically polymerizable component is 60% by weight or more.
<5> The curable adhesive composition according to any one of <1> to <4>, further comprising a crosslinking agent (provided that the crosslinking agent is different from the cationically polymerizable component and the radically polymerizable component).
<6> The curable adhesive composition according to <5>, wherein the crosslinking agent is a polyfunctional isocyanate compound.
<7> The curable adhesive composition according to any one of <1> to <6>, wherein the resin is a polyolefin.
<8> The curable adhesive composition according to any one of <1> to <7>, which is an active energy ray-curable adhesive composition.
<9> The curable adhesive composition according to any one of <1> to <8>, which is an adhesive composition for use in a packaging material for a storage battery device.

Means for solving the above problems include the following aspects.
<2-1> A curable adhesive composition for bonding metal and resin, the curable adhesive composition containing (1) a cationically polymerizable component containing a cationically polymerizable monomer, and (2) a radically polymerizable component containing a radically polymerizable monomer, the radically polymerizable monomer having at least two ethylenically unsaturated bonds in the molecule, and a monomer content in the curable adhesive composition of 60% by weight or more.
<2-2> The curable adhesive composition according to <2-1>, wherein the radical polymerizable monomer is a (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule.
<2-3> The curable adhesive composition according to <2-1> or <2-2>, in which the (meth)acrylate compound has an aliphatic ring.
<2-4> The curable adhesive composition according to <2-3>, in which the (meth)acrylate compound has a plurality of aliphatic rings.
<2-5> The curable adhesive composition according to any one of <2-1> to <2-4>, in which the content of the radical polymerizable monomer is 30% by weight or more.
<2-6> The curable adhesive composition according to any one of <2-1> to <2-5>, further comprising a crosslinking agent (provided that the crosslinking agent is different from the cationically polymerizable component and the radically polymerizable component).
<2-7> The curable adhesive composition according to <2-6>, wherein the crosslinking agent is a polyfunctional isocyanate compound.
<2-8> The curable adhesive composition according to any one of <2-1> to <2-7>, wherein the resin is a polyolefin.
<2-9> The curable adhesive composition according to any one of <2-1> to <2-8>, which is an active energy ray-curable adhesive composition.
<2-10> The curable adhesive composition according to any one of <2-1> to <2-9>, which is an adhesive composition for a packaging material for an electricity storage device.

The present invention provides a curable adhesive composition for bonding metals and resins that can shorten the bonding process and maintain high peel strength even at high temperatures.

1 is a schematic perspective view showing an example of a heat-fusible member of the present invention. FIG. 2 is a schematic perspective view showing another example of the heat-fusible member of the present invention.

The following description of the constituent elements may be based on a representative embodiment of the present invention, but the present invention is not limited to such an embodiment. In this specification, the word "~" is used to mean that the numerical values before and after it are included as the lower and upper limits.

In the numerical ranges described in this specification in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in this specification, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples.

In this specification, oligomers and polymers are compounds having a linear structural portion formed by consecutively bonding a plurality of monomer units in a molecule, and monomers are compounds not containing such a structural portion. The oligomers and polymers may be homopolymers or copolymers. The number of monomer units contained in the oligomers and polymers is preferably 5 or more, more preferably 10 or more. The weight average molecular weight of the oligomers and polymers is preferably more than 1500, more preferably 2000 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 equivalent. For example, the value measured using the following apparatus and conditions can be used.
Equipment: Tosoh Corporation, model name "HLC-8320"
Column: Tosoh Corporation TSKgel-SuperMultipore HZ-M (4.6 mm ID x 15 cm) x 3 Solvent: Tetrahydrofuran Column temperature: 40°C
Detector: RI (Differential Refractive Index Detector)
Flow rate: 350μL/min

Hereinafter, the curable adhesive composition of the present invention will be described in detail with respect to each of its constituent components. Note that hereinafter, the term "curable adhesive composition" may be abbreviated to "adhesive composition".

1. Cationic Polymerizable Component The cationic polymerizable component contains a cationic polymerizable monomer. The number of cationic polymerizable groups in the cationic polymerizable monomer is not particularly limited, and the cationic polymerizable monomer may be a monofunctional cationic polymerizable monomer or a polyfunctional cationic polymerizable monomer. The number of cationic polymerizable groups contained in the cationic polymerizable monomer is preferably 1 to 10, more preferably 2 to 6, because this can increase heat resistance and adhesiveness.

The content 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.

The content of the cationic polymerizable monomer in the cationic 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.

As the cationic polymerizable monomer, a low molecular weight compound is preferred because it allows for low viscosity. The molecular weight of the cationic polymerizable monomer is preferably 50 to 1500, more preferably 100 to 1000, and particularly preferably 200 to 500.

Cationically polymerizable monomers that can be used as the cationic polymerizable component are not particularly limited, but examples 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.

Preferred examples of the epoxy compound include a compound having one epoxy group in the molecule (hereinafter referred to as a "monofunctional epoxy compound") and a compound having two or more epoxy groups in the molecule (hereinafter referred to as a "polyfunctional epoxy compound").
Examples of epoxy compounds include 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"), and compounds other than the above-mentioned "alicyclic epoxy compounds" that have an epoxy group and do not contain an aromatic ring (hereinafter referred to as "aliphatic epoxy compounds"). 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 from 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. In addition, the aliphatic epoxy compound may also contain an aliphatic ring like the alicyclic epoxy compound (however, no epoxy group is present between two adjacent carbon atoms constituting the aliphatic ring).

Examples of aromatic epoxy compounds include bisphenol-type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of bisphenol S, diglycidyl ether of brominated bisphenol A, diglycidyl ether of brominated bisphenol F, diglycidyl ether of brominated bisphenol S, diglycidyl ether of rubber-modified bisphenol A, and di- or polyglycidyl ether of bisphenol fluorene or its alkylene oxide adduct; phenol Novolac type epoxy resins such as phenol novolac type epoxy resins, brominated phenol novolac type epoxy resins, and dicyclopentadiene-phenol novolac type epoxy resins; naphthalene type epoxy resins; alkyl diphenol type epoxy resins; naphthol type epoxy resins; biphenyl type epoxy resins; hydroquinone diglycidyl ether; resorcinol diglycidyl ether; terephthalic acid diglycidyl ether; phthalic acid diglycidyl ether; N,N,N',N'-tetraglycidyl-m-xylylenediamine, etc.

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

Specific examples of aliphatic epoxy compounds 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; polyglycidyl ethers of polyhydric alcohols such as di- or triglycidyl ethers of trimethylolethane, trimethylolpropane, glycerin, and its alkylene oxide adducts, and di-, tri-, or tetraglycidyl ethers of pentaerythritol and its alkylene oxide adducts; di- or polyglycidyl ethers of hydrogenated bisphenol A and its alkylene oxide adducts; tetrahydrophthalic acid diglycidyl ether; and hydroquinone diglycidyl ether.

The number of epoxy groups contained in the epoxy compound is preferably 1 to 10, and more preferably 2 to 6, because this increases heat resistance and adhesiveness.

Only one type of epoxy compound can be used, or two or more types can be used in combination.

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. Preferred examples of the oxetane compound include compounds having one oxetanyl group in the molecule (hereinafter referred to as "monofunctional oxetanes") and compounds having two or more oxetanyl groups in the molecule (hereinafter referred to as "polyfunctional oxetanes").

Preferred examples of monofunctional oxetanes include monofunctional oxetanes containing an alkoxyalkyl group, such as 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, monofunctional oxetanes containing an aromatic group, such as 3-ethyl-3-phenoxymethyloxetane, and monofunctional oxetanes containing a hydroxyl group, such as 3-ethyl-3-hydroxymethyloxetane.

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.

From the viewpoint of coatability and adhesion to substrates, the oxetane compound is preferably one having a molecular weight of 500 or less and being liquid at room temperature. Furthermore, in terms of the excellent durability of the cured product, monofunctional oxetanes having an aromatic ring in the molecule or polyfunctional oxetanes are 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.

Oxetane compounds can be used alone or in combination of two or more types.

Specific examples of vinyl ether compounds include cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol divinyl ether, and cyclohexanedimethanol divinyl ether.

Cyclic ether compounds other than epoxy compounds and oxetane compounds are not particularly limited, but examples include compounds having a cyclic ether with a 5- to 10-membered ring. More specifically, cyclic ether compounds such as tetrahydrofuran and 2,3-dimethyltetrahydrofuran are preferably used.

Cyclic acetal compounds are not particularly limited, but examples include compounds having a cyclic acetal with a 4- to 10-membered ring. More specifically, cyclic acetal compounds such as trioxane, 1,3-dioxolane, and 1,3,6-trioxanecyclooctane are preferably used.

Cyclic iminoether compounds are not particularly limited, but examples include compounds having a cyclic iminoether with a 4- to 10-membered ring. More specifically, cyclic iminoether compounds such as 2-oxazoline, 1,2-oxazine, and 1,3-oxazine are preferably used.

The cationic polymerizable component may further include a cationic polymerizable compound other than the cationic polymerizable monomer. That is, the cationic polymerizable compound may include at least one selected from the group consisting of cationic polymerizable oligomers and cationic polymers in addition to the cationic polymerizable monomer. Examples of cationic polymerizable oligomers and cationic polymers include oligomers and polymers having cationic polymerizable groups at their terminals (e.g., diglycidyl ethers of hydroxyl-terminated oligomers and polymers such as polyalkylene glycols and polyalkylene polyols), and those having a linear structure formed by successively bonding monomer units having cationic polymerizable groups (e.g., phenol novolac type epoxy resins, cresol novolac type epoxy resins).

The cationic polymerizable component preferably contains an epoxy compound selected from the group consisting of epoxy monomers, epoxy oligomers, and epoxy polymers, and the content of the epoxy compound in the cationic 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. When the cationic polymerizable component is composed only of an epoxy compound, the cationic polymerizable component contains at least an epoxy monomer as a cationic polymerizable monomer.

The cationic polymerizable component preferably contains an aliphatic epoxy compound or an alicyclic epoxy compound. By containing 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 weight or more, more preferably 50% by weight or more, particularly preferably 70% by weight or more, and may be 100% by weight.

1-2. Form containing polyfunctional epoxy monomer In one embodiment of the present invention, the cationic polymerizable component preferably contains an epoxy monomer having two or more epoxy groups in the molecule (hereinafter referred to as "polyfunctional epoxy monomer") as a cationic polymerizable monomer. The number of epoxy groups contained in the polyfunctional epoxy monomer is preferably 2 to 10, more preferably 2 to 6, because this can increase heat resistance and adhesiveness.

The content of the polyfunctional epoxy monomer in the cationic 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.

As the polyfunctional epoxy monomer, a low molecular weight compound is preferred because it allows for low viscosity. The molecular weight of the polyfunctional epoxy monomer is preferably 50 to 1500, more preferably 100 to 1000, and particularly preferably 200 to 500.

The polyfunctional epoxy monomer may be an aromatic epoxy monomer, an alicyclic epoxy monomer, an aliphatic epoxy monomer, or the like. The number of carbon atoms in the aliphatic ring contained in the alicyclic epoxy monomer is not particularly limited, but is preferably 3 to 20, more preferably 4 to 10, and particularly preferably 5 to 8. The aliphatic epoxy monomer preferably has a linear or branched aliphatic carbon chain. Here, the aliphatic carbon chain is a carbon chain formed only from 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, no epoxy group exists between two adjacent carbon atoms constituting the aliphatic ring) like the alicyclic epoxy compound. Specific examples of polyfunctional epoxy monomers are the same as those described above.

The polyfunctional epoxy monomer preferably contains an aliphatic epoxy monomer or an alicyclic epoxy monomer. By containing an aliphatic epoxy monomer or an alicyclic epoxy monomer in the adhesive composition, the peel strength can be improved. The total amount of the aliphatic epoxy monomer and the alicyclic epoxy monomer in the cationic 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.

Multifunctional epoxy monomers can be used as a single compound or as a combination of two or more compounds.

In addition to the polyfunctional epoxy monomer, the adhesive composition may further contain an epoxy monomer having one epoxy group in the molecule (hereinafter referred to as a "monofunctional epoxy monomer").

The cationic polymerizable component may contain a cationic polymerizable monomer other than an epoxy monomer. The cationic polymerizable monomer that can be used as the cationic polymerizable component is not particularly limited, but examples include oxetane compounds, vinyl ether compounds, epoxy compounds, and cyclic ether compounds other than oxetane compounds, cyclic acetal compounds, and cyclic imino ether compounds. Specific examples of these cationic polymerizable monomers are the same as those described above.

2. Radically Polymerizable Component The radically polymerizable component is an unsaturated compound having at least one ethylenically unsaturated bond in the molecule. The radically polymerizable component includes a radically polymerizable monomer.

The number of ethylenically unsaturated bonds contained in the radical polymerizable monomer is preferably 1 to 10, and more preferably 2 to 6, because this increases heat resistance and adhesiveness.

The content 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.

The content 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.

The radical polymerizable monomer is preferably a low molecular weight compound because it allows for low viscosity. The molecular weight of the radical polymerizable monomer is preferably 50 to 1500, more preferably 100 to 1000, and particularly preferably 200 to 500.

Radically polymerizable monomers include, for example, (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 a (meth)acryloyl group.

The polyfunctional (meth)acrylate compound is not particularly limited, but examples thereof include the following compounds:

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 an ethylene oxide adduct of bisphenol A, di(meth)acrylate of an alkylene oxide adduct of bisphenol A including di(meth)acrylate of a propylene oxide adduct of bisphenol A, 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 glycerin;
di(meth)acrylates of bisphenol alkylene oxide adducts, such as di(meth)acrylate of bisphenol A alkylene oxide adducts, and di(meth)acrylate of bisphenol F alkylene oxide adducts;
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 isocyanuric acid alkylene oxide adducts;
1,3,5-tri(meth)acryloylhexahydro-s-triazine, and the like.

(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, etc.

　Monofunctional (meth)acrylate compounds are not particularly limited, but examples include the following compounds:

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;
alicyclic monofunctional (meth)acrylates such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, 1,4-cyclohexanedimethylol mono(meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate;
Monofunctional (meth)acrylates having an aromatic ring, such as benzyl (meth)acrylate, (meth)acrylate of a p-cumylphenol alkylene oxide adduct, (meth)acrylate of an o-phenylphenol alkylene oxide adduct, (meth)acrylate of a phenol alkylene oxide adduct, and (meth)acrylate of a nonylphenol alkylene oxide adduct (here, examples of the alkylene oxide include ethylene oxide and propylene oxide);
alkoxyalkyl (meth)acrylates such as 2-methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and (meth)acrylate of an alkylene oxide adduct of 2-ethylhexyl alcohol;
Mono(meth)acrylates of dihydric alcohols such as ethylene glycol mono(meth)acrylate, propylene glycol mono(meth)acrylate, pentanediol mono(meth)acrylate, and hexanediol mono(meth)acrylate;
mono(meth)acrylates of polyalkylene glycols, such as 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;
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, and the like.

Compounds having an ethylenically unsaturated bond other than a (meth)acryloyl group can also be used as the radical polymerizable component. Examples of compounds having an ethylenically unsaturated bond other than a (meth)acryloyl group include compounds having a vinyl group, compounds having an allyl group, and unsaturated carboxylic acids. Specific examples of compounds having a vinyl group include 1,4-butanediol divinyl ether, N-vinyl-2-pyrrolidone, divinyl adipate, and divinyl sebacate. Specific examples of 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 unsaturated carboxylic acids include maleic acid and itaconic acid.

In one embodiment, the radical polymerizable monomer preferably has an aliphatic structure. The aliphatic structure is a structure formed from saturated carbon-carbon bonds that do not contain aromatic carbons. For example, the radical 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, and more preferably 4 to 15. The aliphatic structure may be a straight chain or a branched chain. The aliphatic structure preferably has an aliphatic ring, and the aliphatic structure may be formed only from an aliphatic ring. Although not particularly limited, the radical polymerizable monomer preferably contains 2 to 5 aliphatic rings, and more preferably has 2 to 3 aliphatic rings. The radical polymerizable monomer may contain a bridged condensed ring and may contain multiple aliphatic rings within the bridged condensed ring. For example, the radical polymerizable monomer may contain two aliphatic rings that share two or more carbon atoms. The number of carbon atoms in the aliphatic ring is not particularly limited, but is preferably 3 to 20, and more preferably 4 to 10.

In the radical polymerizable monomer, the content of the radical 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.

In the radical polymerizable monomer, the content of the radical 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.

In one embodiment, it is preferable that the radical polymerizable monomer does not have any reactive groups other than the ethylenically unsaturated bond. In particular, it is preferable that the radical polymerizable monomer does not contain a hydroxyl group or a phosphate group. In the radical polymerizable monomer, the content ratio of the radical 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.

The radically polymerizable component may further include a radically polymerizable compound other than the radically polymerizable monomer. That is, the radically polymerizable component may include at least one selected from the group consisting of radically polymerizable oligomers and radically polymerizable polymers in addition to the radically polymerizable monomer. Examples of the radically polymerizable oligomers and radically polymerizable polymers include those having an ethylenically unsaturated bond at the end of the oligomer or polymer, particularly those having an acryloyl group at the end of the oligomer or polymer (e.g., urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate).

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

The total content of the cationically polymerizable components and the radically polymerizable components 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. There is no particular upper limit to the total content of the cationically polymerizable components and the radically polymerizable components in the adhesive composition, but the total content may be, for example, 99.9% by weight or less.

2-2. Form containing unsaturated compound having at least two ethylenically unsaturated bonds in the molecule In one embodiment of the present invention, the radical polymerizable component contains a radical polymerizable monomer having at least two ethylenically unsaturated bonds in the molecule (hereinafter, also referred to as a polyfunctional (meth)acrylate compound). The number of ethylenically unsaturated bonds contained in the radical polymerizable monomer is preferably 2 to 10, more preferably 2 to 6, because this can increase heat resistance and adhesiveness.

Radically polymerizable monomers having at least two ethylenically unsaturated bonds in the molecule include, for example, (meth)acrylate compounds having two or more (meth)acryloyl groups in the molecule and compounds having two or more ethylenically unsaturated bonds other than (meth)acryloyl groups in the molecule.

The (meth)acrylate compound having two or more (meth)acryloyl groups in the molecule is not particularly limited, and specific examples are the same as those described above.

Examples of compounds having two or more ethylenically unsaturated bonds other than (meth)acryloyl groups in the molecule include compounds having two or more vinyl groups in the molecule and compounds having two or more allyl groups in the molecule. There are no particular limitations on the compounds having two or more ethylenically unsaturated bonds other than (meth)acryloyl groups in the molecule, and specific examples are the same as those described above.

The radically polymerizable component may contain a radically polymerizable monomer having one ethylenically unsaturated bond in the molecule. Examples of radically polymerizable monomers having one ethylenically unsaturated bond in the molecule include (meth)acrylate compounds having one (meth)acryloyl group in the molecule, and compounds having one ethylenically unsaturated bond other than a (meth)acryloyl group in the molecule. Specific examples of these are the same as those described above.

3. Polymerization initiator The adhesive composition may contain a polymerization initiator. Note that, depending on the applied curing means such as active energy rays, even in the absence of a polymerization initiator, the polymerizable compound can initiate polymerization, so the polymerization initiator is an optional component, and the adhesive composition does not need to contain a polymerization initiator.

The polymerization initiator can be selected from the group consisting of photocationic polymerization initiators, thermal cationic polymerization initiators, and photoradical polymerization initiators.

A photocationic polymerization initiator generates cationic species or Lewis acids when exposed to active energy rays such as visible light, ultraviolet light, X-rays, or electron beams, and initiates the polymerization reaction of cationic polymerizable components such as epoxy groups and oxetanyl groups.

By incorporating a cationic photopolymerization initiator, curing at room temperature becomes possible, and good adhesion can be achieved between metal and resin. In addition, since cationic photopolymerization initiators act catalytically when irradiated with active energy rays, they have excellent storage stability and workability even when mixed with cationic polymerizable components. Examples of cationic photopolymerization initiators that generate cationic species or Lewis acids when irradiated with active energy rays include onium salts such as aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts, and iron-allene complexes.

Examples of aromatic diazonium salts include the following compounds.
benzenediazonium hexafluoroantimonate,
benzenediazonium hexafluorophosphate,
Benzenediazonium hexafluoroborate and the like.

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.

Examples of the aromatic sulfonium salt 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)diphenylsulfide bishexafluorophosphate,
4,4'-bis[di(β-hydroxyethoxy)phenylsulfonio]diphenyl sulfide bishexafluoroantimonate,
4,4'-bis[di(β-hydroxyethoxy)phenylsulfonio]diphenyl sulfide bishexafluorophosphate,
7-[di(p-toluyl)sulfonio]-2-isopropylthioxanthone hexafluoroantimonate,
7-[di(p-toluyl)sulfonio]-2-isopropylthioxanthone tetrakis(pentafluorophenyl)borate,
4-phenylcarbonyl-4'-diphenylsulfonio-diphenylsulfide hexafluorophosphate,
4-(p-tert-butylphenylcarbonyl)-4'-diphenylsulfonio-diphenylsulfide hexafluoroantimonate,
4-(p-tert-butylphenylcarbonyl)-4'-di(p-toluyl)sulfonio-diphenylsulfide tetrakis(pentafluorophenyl)borate, and the like.

Examples of the iron-allene complex include the following compounds.
xylene-cyclopentadienyliron(II) hexafluoroantimonate,
cumene-cyclopentadienyliron(II) hexafluorophosphate,
Xylene-cyclopentadienyliron(II)-tris(trifluoromethylsulfonyl)methanide, and the like.

These cationic photopolymerization initiators may be used alone or in combination of two or more. Among these, aromatic sulfonium salts are particularly preferred because they have ultraviolet absorption properties even in the wavelength range of 300 nm or more, and therefore have excellent curing properties and can give cured products with good mechanical strength and adhesive strength.

Cationic photopolymerization initiators are readily available commercially, for example, under the trade names "Kayarad PCI-220", "Kayarad PCI-620" (both manufactured by Nippon Kayaku Co., Ltd.), "UVI-6992" (manufactured by The 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” (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 Chiba Corporation), "CPI-100 P", "CPI-101A", "CPI-200K", "CPI-210S" (all manufactured by San-Apro Co., Ltd.), etc. are included, and in particular, "UVI-6992" manufactured by Dow Chemical Company, and "CPI-100P", "CPI-101A", "CPI-200K", and "CPI-210S" manufactured by San-Apro Co., Ltd., which contain diphenyl[4-(phenylthio)phenyl]sulfonium as a cationic component, are preferred.

Photoradical polymerization initiators generate radical species when exposed to active energy rays such as visible light, ultraviolet light, X-rays, and electron beams, and start the polymerization reaction of radically polymerizable compounds.

Specific examples of photoradical polymerization initiators include, but are not limited to, the following compounds:

acetophenone-based photopolymerization initiators 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 photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;
Benzophenone-based photopolymerization initiators such as benzophenone, o-benzoylmethylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 2,4,6-trimethylbenzophenone;
Thioxanthone-based photopolymerization initiators such as 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propoxythioxanthone;
acylphosphine oxide photopolymerization initiators 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 photopolymerization initiators such as 1,2-octanedione, 1-[4-(phenylthiophenyl)]-, and 2-(O-benzoyloxime);
Camphorquinone, etc.

Thermal cationic polymerization initiators are activated by heating and induce ring-opening polymerization of cationic polymerizable groups contained in cationic polymerizable compounds such as epoxy compounds and oxetane compounds. Examples of thermal cationic polymerization initiators include benzylsulfonium salts, thiophenium salts, thiolanium salts, benzylammonium salts, pyridinium salts, hydrazinium salts, carboxylate esters, sulfonate esters, and amine imides. These thermal cationic polymerization initiators are readily available commercially, and examples of these, all of which are listed by trade name, include "ADEKAOPTON CP77" and "ADEKAOPTON CP66" (both manufactured by ADEKA Corporation), "CI-2639" and "CI-2624" (both manufactured by Nippon Soda Co., Ltd.), "SAN-AID SI-60L", "SAN-AID SI-80L", and "SAN-AID SI-100L" (both manufactured by Sanshin Chemical Industry Co., Ltd.), etc.

The polymerization initiator may be used alone or in combination of two or more types depending on 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.

Different types of initiators may be used in combination. For example, the peel strength of the adhesive composition may be improved by using a photocationic polymerization initiator in combination with a photoradical polymerization initiator.

4. Other Components The adhesive composition may further contain any other components different from the above-mentioned components, provided that the effects of the present invention are not impaired.

Another type of other component is a crosslinking agent capable of crosslinking at least one of the cationic polymerizable component and the radical polymerizable component. There are no particular limitations on the crosslinking agent, and it may be a crosslinking agent that reacts with the cationic polymerizable component and/or the radical polymerizable component during or after polymerization to form crosslinks, depending on conditions such as heat and moisture. Note that the crosslinking agent here is different from the cationic polymerizable component and the radical polymerizable component.

In one embodiment, it is preferable to use a polyfunctional isocyanate compound as a crosslinking agent. The isocyanate groups contained in the polyfunctional isocyanate compound can react with functional groups such as hydroxyl groups contained in the polymerization product of the cationic polymerizable component to crosslink the polymerization products. The high-temperature peel strength of the adhesive composition can be improved by the polyfunctional isocyanate compound forming crosslinks. Furthermore, the solvent resistance of the adhesive composition can be improved by the polyfunctional isocyanate compound forming crosslinks. For example, even after contact with an electrolyte solvent such as ethylene carbonate or diethylene carbonate, an adhesive composition containing a polyfunctional isocyanate compound can maintain a higher peel strength.

A polyfunctional isocyanate compound is a compound having two or more isocyanate groups, and is particularly preferably a compound having two isocyanate groups.

The polyfunctional isocyanate compound is not particularly limited, and various polyfunctional isocyanate compounds of aromatic, aliphatic, and alicyclic types can be used. Examples of polyfunctional isocyanate compounds include pentamethylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and norbornane diisocyanate.

In this specification, the term "polyfunctional isocyanate compound" includes not only polyfunctional isocyanate compounds but also derivatives formed from polyfunctional isocyanate compounds, unless otherwise specified. Derivatives of polyfunctional isocyanate compounds are compounds in which isocyanate groups are changed to isocyanurate bonds, biuret bonds, urethane bonds, allophanate bonds, urea bonds, uretdione bonds, or the like through chemical reactions. Compounds containing isocyanurate bonds are particularly preferred in that they are highly effective in improving adhesion to adherends and can improve room temperature peel strength and electrolyte resistance. The derivatives may be derivatives in which all isocyanate groups have been chemically changed, but are preferably derivatives in which one or more, more preferably two or more, isocyanate groups remain unreacted.

The derivative may be formed from two or more of the same or different polyfunctional isocyanate compounds. Specific examples of such derivatives of polyfunctional isocyanate compounds include multimers of polyfunctional isocyanate compounds. Multimers of polyfunctional isocyanate compounds may be formed through the bonds listed above, such as uretdione bonds, isocyanurate bonds, and allophanate bonds. The polyfunctional isocyanate compounds forming the multimer are usually all the same type of polyfunctional isocyanate compound, but may be different types of polyfunctional isocyanate compounds. The peel strength of the adhesive composition may be improved by using a multimer formed from different types of polyfunctional isocyanate compounds. The number of polyfunctional isocyanate compounds constituting the multimer is not particularly limited, and may be a multimer of a general isocyanate compound. Specifically, the multimer may be a dimer, trimer, tetramer, or the like.

When present, the total amount of polyfunctional isocyanate compounds and their derivatives in the adhesive composition is preferably 1 to 40% by weight, more preferably 2 to 30% by weight, and particularly preferably 3 to 20% by weight.

Another type of component is photosensitizers. By adding a photosensitizer, reactivity is improved, and the mechanical strength and adhesive strength of the cured product can be improved. Examples of photosensitizers include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreducible dyes.

Specific photosensitizers are not particularly limited, and include, for example, 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;
Other examples include α,α-diethoxyacetophenone, benzil, fluorenone, xanthone, uranyl compounds, and halogen compounds.

The photosensitizer functions as a sensitizer for the photocationic polymerization initiator or the photoradical polymerization initiator, and can be appropriately selected and used depending on the polymerization initiator contained in the adhesive composition. These may be used alone or in a mixture of two or more types.

The photosensitizer is preferably contained in the range of 0.1 to 20 parts by weight, based on 100 parts by weight of the total amount of cationic polymerizable components in the adhesive composition.

Polyols have the property of promoting cationic polymerization and can be incorporated into the adhesive composition. Polyols that do not contain any acidic groups other than phenolic hydroxyl groups are preferred, and examples include polyol compounds that do not contain any functional groups other than hydroxyl groups, polyester polyol compounds, polycaprolactone polyol compounds, polyol compounds that contain phenolic hydroxyl groups, polycarbonate polyol compounds, etc.

　Furthermore, as long as the effect of the present invention is not impaired, silane coupling agents, ion trapping agents, antioxidants, light stabilizers, chain transfer agents, sensitizers, tackifiers, thermoplastic resins, fillers, flow control agents, plasticizers, defoamers, leveling agents, pigments, solvents, etc. may also be added.

In this embodiment, it is preferable that the content of oligomers and polymers is reduced. By reducing the content 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, and particularly preferably 90% by weight or more, and may be 100% by weight.

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 components described above, and although it is not particularly limited, the boiling point of the solvent may be, for example, 120°C or less. The content of the solvent in the adhesive composition is preferably 30% by weight or less, more preferably 20% by weight or less, and particularly preferably 10% by weight or less, and the adhesive composition may not contain a solvent.

5. Curable Adhesive Composition The adhesive composition can be produced by mixing the above-mentioned components, optionally further mixing other components, and stirring in a conventional manner.
In this case, heating may be performed as necessary. The heating temperature may be appropriately set depending on the adhesive composition used, the substrate, the purpose, etc., but is preferably 30 to 80°C.

The viscosity of the adhesive composition at 25°C is preferably 10 to 1,000 mPa·s, as this provides excellent coating properties for substrates.

6. Method of Use The adhesive composition of the present invention can be used to bond different materials such as metal and resin. Specific examples of the method of use include a method in which the adhesive composition is applied to a substrate, then laminated to another substrate, and cured by irradiation with active energy rays or heating. Thus, the adhesive composition may be of the active energy ray curing type or the heat curing type, but the active energy ray curing type is particularly preferred.

The resin is not particularly limited, and examples thereof include 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 in particular, a non-stretched resin film is preferable.

Specific examples of metals include gold, silver, copper, aluminum, iron, nickel, titanium, stainless steel, and chrome molybdenum steel. The metal to be bonded is preferably processed into a metal plate, a flat metal plate, or a metal foil.

Coating of the substrate may be performed according to a conventionally known method, and examples of such methods include a natural coater, knife belt coater, floating knife, knife over roll, 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.
The coating thickness of the adhesive composition of the present invention may be selected depending on the substrate and application, but is preferably 0.1 to 100 μm, more preferably 1 to 25 μm.

Activin energy rays include visible light, ultraviolet light, X-rays, and electron beams, but ultraviolet light is preferred because inexpensive equipment can be used.

When curing with ultraviolet light, various light sources can be used, such as pressurized or high-pressure mercury lamps, metal halide lamps, xenon lamps, electrodeless discharge lamps, carbon arc lamps, and LEDs. Among these, high-pressure mercury lamps and metal halide lamps are preferred, and metal halide lamps are particularly preferred. The amount of ultraviolet light irradiation is preferably 200 to 2,000 mJ/ ^cm2 , more preferably 300 to 1,500 mJ/ ^cm2 in the UV-A region (near 365 nm).

When curing with electron beams, various types of electron beam irradiation equipment can be used, such as Cockcroft-Waldsing type, Van de Graaff type, and resonant transformer type equipment. The absorbed dose of the electron beam is preferably 1 to 200 kGy, more preferably 10 to 100 kGy. The acceleration voltage of the electron beam may be appropriately set in the range of 80 to 300 kV depending on the film thickness of the substrate. For example, if the film thickness of the substrate is 100 μm, 200 kV is preferable. The oxygen concentration of the electron beam irradiation atmosphere is preferably 500 ppm or less, more preferably 300 ppm or less.

7. Heat-sealable members Heat-sealable members can be produced using the adhesive composition.
The heat-fusible member of the present invention comprises an adhesive layer formed by curing the adhesive composition of the present invention, a metal layer bonded to one side of the adhesive layer, and a heat-fusible resin layer bonded to the other side of the adhesive layer.

Schematic diagrams of the heat-sealable member are shown in Fig. 1 and Fig. 2. That is, the heat-sealable member 1 in Fig. 1 sequentially comprises a heat-sealable resin layer 11, an adhesive layer 12, and a metal layer 13. Also, the heat-sealable member 1 in Fig. 2 sequentially comprises a heat-sealable resin layer 11, an adhesive layer 12, a metal layer 13, and another layer 14.

The shape of the heat-sealable member can be set appropriately depending on the application, etc., and is not particularly limited, but examples include a film, sheet, plate, etc.

The above-mentioned heat-sealable resin layer is a layer containing a resin that can melt by heat and fuse the material constituting the layer on one side with the material constituting the layer on the other side. 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. Furthermore, as polyolefin resins, polyethylene and polypropylene are preferred. In particular, when the heat-sealable member is used to integrate with other members, it is preferred that the resin is unstretched because there is little dimensional change (shrinkage), and unstretched polyethylene and unstretched polypropylene are more preferred.

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

The thickness of the above-mentioned heat-sealable resin layer is not particularly limited and depends on the resin material, but for example, if the layer contains unstretched polypropylene, it is preferably 10 μm to 200 μm, more preferably 20 μm to 100 μm. If the thickness of the layer containing unstretched polypropylene is 10 μm to 200 μm, it is possible to obtain a heat-sealed composite product such as a sealed container that is not easily broken and has high durability.

The adhesive layer is a layer formed by curing the adhesive composition. The thickness of the adhesive layer is not particularly limited, but is preferably 1 μm to 20 μm, and particularly preferably 2 μm to 10 μm. If the thickness of the adhesive layer is 1 μm to 20 μm, the heat-sealable member can be easily processed, for example, by bending, when it is in the form of a sheet.

The metal layer is a layer containing a metal or an alloy. Examples of metals or alloys include aluminum, iron, titanium, magnesium, copper, nickel, chromium, and other metals, as well as alloys thereof. Among these, aluminum is preferred due to its excellent workability. The thickness of the metal layer is not particularly limited, depending on the 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.

When the heat-sealable member includes a metal layer, another layer 14 can be provided on the surface of the metal layer 13 as shown in FIG. 2. The material constituting the other layer preferably includes a resin from the viewpoint of protecting the metal layer. That is, the other layer is preferably a resin layer. This resin is not particularly limited and can be polyamide resin, polyester resin, etc. 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 it is made into a sealed container as a heat-sealed composite product. The other layer may have a multi-layer structure, and may include, for example, 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.

When heat-sealable materials are used in lithium-ion battery packaging materials, their adhesive performance can be maintained even if there are temperature changes during battery storage or use, and in particular, their adhesive performance can be maintained during chemical temperature increases in the battery constituent materials that accompany charging or discharging, in temperature ranges higher than normal temperatures such as in summer or inside a car, and in temperature ranges lower than the outside air temperature in cold regions.

The method for producing the heat-fusible member shown in FIG. 1 is as follows.
(1) A method in which an adhesive composition is applied to the surface of a metal foil or the like for forming a metal layer 13 to form an adhesive layer 12, and then a resin film for forming a heat-fusible resin layer 11 (hereinafter referred to as a "heat-fusible resin film") is brought into contact with the surface on which the adhesive layer 12 is formed, pressed against the surface, and then exposed to active energy rays.

(2) A method in which an adhesive composition is applied to the surface of a heat-sealable resin film to form an adhesive layer 12, and then a metal foil or the like for forming a metal layer 13 is brought into contact with the surface on which the adhesive layer 12 is formed, pressure-bonded, and active energy rays are irradiated.

The method for producing the heat-fusible member shown in FIG. 2 is as follows.
(3) A method in which an adhesive composition is applied to the surface of metal layer 13 in a composite film having a resin layer constituting another layer 14 and a metal layer 13 formed on one side of the resin layer by lamination, vapor deposition, or the like to form an adhesive layer 12, and then the surface on which the adhesive layer 12 is formed is brought into contact with a heat-fusible resin film, pressure-bonded, and irradiated with active energy rays.

(4) A method in which an adhesive composition is applied to the surface of a heat-sealable resin film to form an adhesive layer 12, and then the surface on which the adhesive layer 12 is formed is brought into contact with the surface on which the metal layer 13 is formed of a composite film having a resin layer constituting another layer 14 and a metal layer 13 formed on one side of the resin layer by lamination, vapor deposition, or the like, and pressure-bonded, and then exposed to active energy rays.

(5) A method of extruding a film for forming another layer 14 onto the surface of the metal layer 13 in the laminate obtained by the method (1) or (2) above.

The adhesive composition is often applied to the surface of a metal layer forming material such as metal foil, or a metal layer in a composite film comprising a metal layer and another layer (resin layer), but is not particularly limited thereto. When using a metal foil, it is preferable to use an aluminum foil having a thickness of 20 μm to 100 μm. This makes it possible to easily form a heat-sealable member in which damage is suppressed. When using a composite film, it is preferable that the metal layer contains aluminum, and the other layer (resin layer) contains polyamide resin, polyester resin, etc. Furthermore, when manufacturing the heat-sealable member shown in FIG. 2 without using a composite film, that is, when the above method (5) is adopted, it is preferable to use a film containing polyamide resin, polyester resin, etc. as the film for forming the other layer 14.

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

8. Packaging material for power storage device The heat-sealable member can be used in various industrial product fields such as the electrical field, the automotive field, the industrial field, and other fields. The heat-sealable member is particularly preferably used as a packaging material for power storage devices because it has high hot peel strength, excellent adhesion, and high electrolyte resistance. Examples of the power storage device packaging material that can be used include secondary batteries such as lithium ion batteries and lithium ion polymer batteries.

The present invention will be explained in more detail below with examples and comparative examples, but the present invention is not limited to these examples.

(Preparation of Adhesive Composition)
The components shown in the following table were blended in the amounts shown in the table for each example, and mixed by stirring to prepare an adhesive composition. Details of the abbreviations in the table are as follows. The amount of each component in the table represents the weight ratio.
<Epoxy Monomer>
Epogosey BD: 1,4-butanediol diglycidyl ether, "Epogosey BD (D)" manufactured by Yokkaichi Chemical Co., Ltd.
EX-211: Neopentyl glycol diglycidyl ether, "Denacol EX-211" manufactured by Nagase ChemteX Corporation
EX-212: 1,6-hexanediol diglycidyl ether, "Denacol EX-212" manufactured by Nagase ChemteX Corporation
Celloxide 2021P: 3,4-epoxycyclohexylmethyl (3,4-epoxy)cyclohexanecarboxylate, "Celloxide 2021P" manufactured by Daicel Corporation
EX-252: Hydrogenated bisphenol A diglycidyl ether, "Denacol EX-252" manufactured by Nagase ChemteX Corporation
EX-321: Trimethylolpropane polyglycidyl ether, "Denacol EX-321" manufactured by Nagase ChemteX Corporation
EX-121: 2-ethylhexyl glycidyl ether, "Denacol EX-121" manufactured by Nagase ChemteX Corporation
<Epoxy Oligomer>
jER828: Bisphenol A diglycidyl ether, "jER828" manufactured by Mitsubishi Chemical Corporation
R-45EPT: Polybutadiene diglycidyl ether, "Denalex R-45EPT" manufactured by Nagase ChemteX Corporation
<Oxetane Monomer>
OXT-221: 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane, "Aronix (registered trademark) OXT-221" manufactured by Toagosei Co., Ltd.
<Vinyl ether monomer>
BDVE: 1,4-butanediol divinyl ether, "BDVE" manufactured by Nippon Carbide Industries Co., Ltd.
CHDVE: 1,4-cyclohexanedimethanol divinyl ether, "CHDVE" manufactured by Nippon Carbide Industries Co., Ltd.
<Acrylic Monomer>
Light Acrylate DCP-A: Tricyclodecane dimethylol diacrylate, "Light Acrylate DCP-A" manufactured by Kyoeisha Chemical Co., Ltd.
M-215: Isocyanuric acid EO-modified diacrylate, "Aronix (registered trademark) M-215" manufactured by Toagosei Co., Ltd.
Light Acrylate NP-A: Neopentyl glycol di(meth)acrylate, "Light Acrylate NP-A" manufactured by Kyoeisha Chemical Co., Ltd.
M-211B: Bisphenol A EO-modified (n≒2) diacrylate, "Aronix (registered trademark) M-211B" manufactured by Toagosei Co., Ltd.
M-240: Polyethylene glycol (n≒4) diacrylate, "Aronix (registered trademark) M-240" manufactured by Toagosei Co., Ltd.
IPEMA: isoprenyl methacrylate, "IPEMA" manufactured by Kuraray Co., Ltd.
M-305: Pentaerythritol tri- and tetraacrylate, "Aronix (registered trademark) M-305" manufactured by Toagosei Co., Ltd.
M-313: Isocyanuric acid EO-modified di- and triacrylate, "Aronix (registered trademark) M-313" manufactured by Toagosei Co., Ltd.
M-315: Isocyanuric acid EO-modified di- and triacrylate, "Aronix (registered trademark) M-315" manufactured by Toagosei Co., Ltd.
M-120: 2-ethylhexyl EO-modified (n≒2) acrylate, "Aronix (registered trademark) M-120" manufactured by Toagosei Co., Ltd.
M-5700: 2-hydroxy-3-phenoxypropyl acrylate, "Aronix (registered trademark) M-5700" manufactured by Toagosei Co., Ltd.
<Acrylic Oligomer>
M-1200: urethane acrylate (bifunctional), "Aronix (registered trademark) M-1200" manufactured by Toagosei Co., Ltd.
<Polymerization inhibitor>
BHT: 2,6-di-tert-butyl-p-cresol, "BHT" manufactured by Nikki Universal Co., Ltd.
<Photocationic Polymerization Initiator>
CPI-110P: diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate, "CPI-110P" manufactured by San-Apro Co., Ltd.
IK-1: diaryliodonium salt, "IK-1" manufactured by San-Apro Co., Ltd.
<Photoradical polymerization initiator>
Omnirad 184D: 1-hydroxycyclohexyl phenyl ketone, "Omnirad 184D" manufactured by IGM Resins
<Isocyanate Compound>
TPA-100: Polyisocyanate of hexamethylene diisocyanate, "Duranate TPA-100" manufactured by Asahi Kasei Corporation
NBDI: 2,5(2,6)-bis(isocyanatomethyl)bicyclo[2.2.1]heptane, "Cosmonate NBDI" manufactured by Mitsui Chemicals, Inc.
H ₆ -XDI: 1,3-bis(isocyanatomethyl)cyclohexane, "Takenate 600" manufactured by Mitsui Chemicals, Inc.

(Preparation of test pieces for evaluating peel strength)
An adhesive composition was applied to the chemically treated surface of an aluminum foil having a thickness of 40 μm, and a corona discharge-treated CPP (cast polypropylene) film having a thickness of 80 μm was superimposed on the surface coated with the adhesive. The laminated film was sandwiched between two sheets of copy paper on the top and bottom, and passed through a roll laminator at room temperature so that the average thickness of the adhesive was 2 μm to 4 μm. When measuring the peel strength to be performed later, the adhesive was not applied to the part that was clamped by the gripping tool of the tensile tester. The laminated film was removed, and then ultraviolet light was irradiated from the CPP film side of the laminated film using a conveyor-type ultraviolet irradiator manufactured by Eye Graphics Co., Ltd. (high pressure mercury lamp, irradiation intensity in the UV-A region 280 mW/cm ² , accumulated light amount 600 mJ/cm ² , all measured values of UV POWER PUCK II manufactured by Heraeus Co., Ltd.) to cure the adhesive composition and prepare a test piece. The next day, the sample was cut into a 15 mm wide rectangular piece to prepare a test piece for evaluating peel strength.

(Measurement of Peel Strength)
Using a thermostatic tensile tester (Autograph AGS-X manufactured by Shimadzu Corporation), a T-peel test was performed at a pulling speed of 100 mm/min until the gripper moved 100 mm, and 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: room temperature (rt, 23°C) and 80°C.

 

 

 

 

 

The Examples containing a radically polymerizable component together with a cationic polymerizable component had higher peel strengths at both room temperature and 80° C. than Comparative Examples 1 to 5 not containing a cationic polymerizable compound, Comparative Example 6 not containing a radically polymerizable compound, and Comparative Example 7 not containing an epoxy monomer. Furthermore, the Examples in which a polyfunctional isocyanate compound was added had improved peel strengths at both room temperature and 80° C. compared to the other Examples.

Claims (9)

A curable adhesive composition for bonding metal and resin, comprising:
The curable adhesive composition is
(1) a cationically polymerizable component including a cationically polymerizable monomer;
(2) a radically polymerizable component including a radically polymerizable monomer;
Contains
The curable adhesive composition, wherein the cationically polymerizable component comprises an epoxy monomer having two or more epoxy groups. The curable adhesive composition according to claim 1, wherein the epoxy monomer comprises at least one epoxy monomer selected from the group consisting of aliphatic epoxy monomers and cycloaliphatic epoxy monomers. The curable adhesive composition according to claim 1, wherein the epoxy monomer comprises an aliphatic epoxy monomer, and the aliphatic epoxy monomer has an aliphatic carbon chain having 3 to 20 carbon atoms. The curable adhesive composition according to claim 1, wherein the total content of the cationically polymerizable component and the radically polymerizable component is 60% by weight or more. The curable adhesive composition of claim 1 further comprising a crosslinking agent (wherein the crosslinking agent is different from the cationically polymerizable component and the radically polymerizable component). The curable adhesive composition according to claim 5, wherein the crosslinking agent is a polyfunctional isocyanate compound. The curable adhesive composition according to claim 1, wherein the resin is a polyolefin. The curable adhesive composition according to claim 1, which is an active energy ray curable adhesive composition. The curable adhesive composition according to claim 1 , which is an adhesive composition for use as a packaging material for an electricity storage device.