Curable adhesive composition

Abstract

To provide a new curable adhesive composition capable of maintaining high peel strength to a polyolefin-based resin film from room temperature to high temperature.SOLUTION: The curable adhesive composition of the present disclosure contains (1) at least one cationically polymerizable component selected from the group consisting of cationically polymerizable monomers, cationically polymerizable oligomers, and cationically polymerizable polymers, and (2) at least one radically polymerizable component selected from the group consisting of radically polymerizable monomers, radically polymerizable oligomers, and radically polymerizable polymers, wherein the radically polymerizable component contains at least an alicyclic (meth) acrylate, and the alicyclic (meth) acrylate is a polyfunctional (meth) acrylate having at least two (meth) acryloyl groups.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Typical packaging materials for energy storage devices used in laminated batteries have a three-layer structure centered around metal foil, with adhesive between each layer. The three layers are the base layer, which becomes the outer layer of the laminated battery after it is formed; the barrier layer, made of metal foil such as aluminum foil or stainless steel foil, which prevents the penetration of moisture and air; and the sealant layer, which serves to insulate the barrier layer from contact with the electrodes and electrolyte and to heat-seal the outer periphery. Each layer may consist of two or more layers. Of these, the sealant layer, which comes into contact with the electrolyte, is typically made of a polyolefin resin film such as polypropylene film.

[0003] An adhesive containing an acid-modified polyolefin and a crosslinking agent is generally used to bond a sealant layer to a metal foil. For example, Patent Document 1 describes a laminating adhesive composition containing a modified polyolefin resin (A), an alcohol-based epoxy compound (B), and a polyfunctional isocyanate compound (C). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-059200 Summary of the Invention [Problem to be solved by the invention]

[0005] Adhesives based on acid-modified polyolefins are commonly used to bond polyolefin-based resin films. However, adhesives using acid-modified polyolefins are used together with crosslinking agents, and there is a problem in that it takes time for the crosslinking agent to form crosslinks. For example, the adhesive described in Patent Document 1 takes time to harden and requires an aging process of several days to achieve high adhesive strength. There is a demand for new adhesives that can quickly demonstrate adhesive performance as adhesives for polyolefin-based resin films.

[0006] An object of one embodiment of the present invention is to provide a new curable adhesive composition that can maintain high peel strength from polyolefin-based resin films at room temperature to high temperatures. [Means for solving the problem]

[0007] The means for solving the above problems include the following aspects. [1] A curable adhesive composition comprising: (1) at least one cationically polymerizable component selected from the group consisting of cationically polymerizable monomers, cationically polymerizable oligomers, and cationically polymerizable polymers; and (2) at least one radically polymerizable component selected from the group consisting of radically polymerizable monomers, radically polymerizable oligomers, and radically polymerizable polymers, wherein the radically polymerizable component contains at least an alicyclic (meth)acrylate, and the alicyclic (meth)acrylate is a polyfunctional (meth)acrylate having at least two (meth)acryloyl groups, and the curable adhesive composition contains a cationic polymerization initiator and may further contain a radical polymerization initiator as an optional component, with the proviso that the content of the radical polymerization initiator in the curable adhesive composition is 4% by weight or less. [2] The curable adhesive composition according to [1], wherein the total amount of the cationically polymerizable component and the radically polymerizable component is 80% by weight or more, and the ratio of the cationically polymerizable component to the radically polymerizable component is 20 / 80 to 70 / 30. [3] The curable adhesive composition according to [2], wherein the content of the alicyclic (meth)acrylate in the radical polymerizable component is 80% by weight or more. [4] The curable adhesive composition according to any one of [1] to [4], wherein the content of the radical polymerization initiator in the curable adhesive composition is 0.5 wt % or less. [5] The curable adhesive composition according to claim 1, wherein the cationically polymerizable component comprises at least one selected from the group consisting of an aliphatic epoxy compound and an alicyclic epoxy compound. [6] The curable adhesive composition according to [5], which contains the alicyclic epoxy compound, and the alicyclic epoxy compound is an epoxy monomer or epoxy oligomer containing an alicyclic group that forms an epoxide between two adjacent carbon atoms that constitute an aliphatic ring. [7] The aliphatic epoxy compound is an epoxy monomer or an epoxy oligomer having epoxy groups bonded to two or more ends of an aliphatic group, and the aliphatic group is -(CH2) n -, where n is an integer from 1 to 15, provided that -(CH2) n The curable adhesive composition according to [6], wherein at least one linking group selected from the group consisting of -O-, -COO-, -CO-, and -OCO- may be inserted between some of the carbon-carbon bonds. [Effects of the Invention]

[0008] According to the present invention, a new curable adhesive composition can be obtained that can maintain high peel strength from polyolefin-based resin films at temperatures ranging from room temperature to high temperatures. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view showing an example of a heat-fusible member of the present invention. [Figure 2] FIG. 2 is a schematic perspective view showing another example of the heat-fusible member of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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 symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0011] In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples. Furthermore, in the present invention, a combination of two or more of the preferred embodiments described below is also a preferred embodiment.

[0012] In this specification, oligomers and polymers are compounds having a linear structural portion in which multiple monomer units are bonded consecutively in the molecule. 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. The molecular weight of the monomer is preferably 1500 or less, more preferably 1000 or less. Oligomers and polymers are distinguished by their weight-average molecular weight, with oligomers being those with a weight-average molecular weight of less than 10,000 and polymers being those with a weight-average molecular weight of 10,000 or more. Here, the weight-average molecular weight refers to the value obtained by converting the molecular weight measured by gel permeation chromatography (hereinafter also referred to as "GPC") into polystyrene equivalents. For example, values ​​measured using the following apparatus and conditions can be used. Device: 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℃ Detector: RI (differential refractive index detector) Flow rate: 350μL / min

[0013] 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."

[0014] 1. Cationic polymerizable component 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, cationically polymerizable monomers are particularly preferred from the viewpoint of coatability. The number of cationically polymerizable groups in one 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, because this can improve heat resistance and adhesiveness.

[0015] 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.

[0016] The content of the cationically polymerizable monomer in the cationically polymerizable component is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and may be 100% by weight.

[0017] The cationically polymerizable monomer is preferably a low-molecular-weight compound because it allows for a low viscosity. The molecular weight of the cationically polymerizable monomer is preferably 50 to 1,500, more preferably 100 to 1,000, and particularly preferably 200 to 500.

[0018] 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 iminoether compounds.

[0019] 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 refers to an alicyclic group in which an epoxy group is directly bonded to 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 but do not contain an aromatic ring (hereinafter referred to as "aliphatic epoxy compounds"). The number of carbon atoms in the alicyclic 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. Aliphatic epoxy compounds preferably have 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 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. The aliphatic epoxy compound may also contain an aliphatic ring (however, no epoxy group is directly bonded to the aliphatic ring) in the same manner as the alicyclic epoxy compound.

[0020] 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 ethers of bisphenol fluorene or its alkylene oxide adduct; 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; alkyldiphenol-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; and N,N,N',N'-tetraglycidyl-m-xylylenediamine.

[0021] The alicyclic epoxy compound may contain, for example, any of the following alicyclic epoxy groups:

[0022] [ka]

[0023] Examples of the alicyclic epoxy compound include dicyclopentadiene dioxide, limonene dioxide, 4-vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl(3,4-epoxy)cyclohexanecarboxylate, dicyclopentadiene diepoxide, bis(3,4-epoxycyclohexylmethyl)adipate, and the like.

[0024] 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.

[0025] The number of epoxy groups contained in the epoxy compound is preferably 1 to 10, and more preferably 2 to 6, because this allows for increased heat resistance and adhesiveness.

[0026] The epoxy compounds can be used alone or in combination of two or more.

[0027] 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 a compound having one oxetanyl group in the molecule (hereinafter referred to as a "monofunctional oxetane") and a compound having two or more oxetanyl groups in the molecule (hereinafter referred to as a "polyfunctional oxetane").

[0028] 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, and hydroxyl group-containing monofunctional oxetanes such as 3-ethyl-3-hydroxymethyloxetane.

[0029] Examples of polyfunctional oxetanes 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.

[0030] From the viewpoints 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 order to obtain a cured product with excellent durability, monofunctional oxetanes having an aromatic ring in the molecule or polyfunctional oxetanes are more preferred. Examples of particularly preferred 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.

[0031] The oxetane compounds may be used singly or in combination of two or more.

[0032] 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, and cyclohexanedimethanol divinyl ether.

[0033] The cyclic ether compounds other than the epoxy compounds and the oxetane compounds are not particularly limited, but examples thereof 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.

[0034] The cyclic acetal compound is not particularly limited, but examples thereof include compounds having a cyclic acetal of 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.

[0035] The cyclic iminoether compound is not particularly limited, but examples thereof 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.

[0036] Examples of cationically polymerizable oligomers and polymers include those having a cationically polymerizable group at the end of the oligomer or polymer (e.g., diglycidyl ethers of hydroxyl-terminated oligomers and polymers such as polyalkylene glycols and polyalkylene polyols), and those having a linear structural portion formed by successively bonding monomer units having a cationically polymerizable group (e.g., phenol novolac epoxy resins, cresol novolac epoxy resins).

[0037] The cationically 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 cationically 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.

[0038] The cationically polymerizable component preferably contains an aliphatic epoxy compound or an alicyclic epoxy compound, and particularly preferably contains both an aliphatic epoxy compound and an alicyclic epoxy compound. The adhesive composition contains an aliphatic epoxy compound or an alicyclic epoxy compound, which can improve peel strength. The total amount of the aliphatic epoxy compound and the alicyclic epoxy compound in the cationically polymerizable component is preferably 30% by weight or more, more preferably 50% by weight or more, and particularly preferably 70% by weight or more, and may be 100% by weight.

[0039] The cationically polymerizable component preferably contains an epoxy monomer, and the content of the epoxy monomer in the cationically 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.

[0040] The cationically polymerizable component preferably contains an aliphatic epoxy compound, particularly an aliphatic epoxy monomer, and an alicyclic epoxy compound, particularly an alicyclic epoxy monomer. The aliphatic epoxy compound and the alicyclic epoxy compound are preferably polyfunctional epoxy compounds, and particularly preferably bifunctional epoxy compounds having two epoxy groups in the molecule. In particular, the alicyclic epoxy compound preferably contains an alicyclic group that forms an epoxide between two adjacent carbon atoms constituting the alicyclic ring, and particularly preferably contains multiple (specifically, two) alicyclic groups. The adhesive composition contains an aliphatic epoxy compound and an alicyclic epoxy compound, thereby improving peel strength. The total amount of the aliphatic epoxy compound, particularly the aliphatic epoxy monomer, and the alicyclic epoxy compound, particularly the alicyclic epoxy monomer, in the cationically 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 even be 100% by weight.

[0041] Aliphatic epoxy compounds, particularly aliphatic epoxy monomers, are preferably those in which an epoxy group is bonded to the end of an aliphatic group. The end of the aliphatic group is not particularly limited, and may be, for example, both terminal carbons if the aliphatic group has a linear structure, or may be, for example, a terminal carbon of any aliphatic chain if the aliphatic group has a branched chain structure, or may be two or more terminal carbons, or may be all terminal carbons. The aliphatic group may be, for example, -(CH2) n - and can be expressed as -(CH2) n A linking group selected from the group consisting of -O-, -COO-, -CO-, and -OCO- may be inserted between some of the carbon-carbon bonds of -. n is an integer of 1 to 15, preferably 1 to 10, and more preferably 2 to 6. -(CH2) nAn aliphatic epoxy monomer can be obtained by attaching epoxy groups to both ends of -. A more specific aliphatic epoxy monomer is -CH2O-(CH2) n It has an aliphatic group represented by -OCH2-, and n is an integer of 1 to 15, preferably 1 to 10, and more preferably 2 to 6, as above.

[0042] The alicyclic epoxy compound, particularly the alicyclic epoxy monomer, may contain multiple aliphatic rings, and the multiple aliphatic rings may be directly bonded, and the —(CH) n They may be bonded via a linking group selected from the group consisting of - (n is an integer selected from 1 to 10), -O-, -COO-, -CO-, -OCO- and combinations thereof. Here, examples of the combined linking group include -(CH2) n It is a linking group in which multiple linking groups are bonded, such as -COO-. The aliphatic ring contained in the alicyclic group is preferably not a bridged fused ring, and is particularly preferably composed of a single aliphatic ring. A bridged fused ring is an aliphatic ring in which two non-adjacent carbon atoms are bridged. The number of carbon atoms in the aliphatic ring is not particularly limited, but is preferably 3 to 20, more preferably 4 to 10, and particularly preferably 5 to 8.

[0043] The weight ratio of the aliphatic epoxy compound to the alicyclic epoxy compound (aliphatic epoxy compound / alicyclic epoxy compound) is preferably 20 / 80 to 80 / 20, more preferably 30 / 70 to 70 / 30, and particularly preferably 40 / 60 to 60 / 40.

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

[0045] The number of ethylenically unsaturated bonds contained in one type of radically polymerizable component is preferably 1 to 10, and more preferably 2 to 6, because this allows for increased heat resistance and adhesiveness.

[0046] 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.

[0047] The content of the radically polymerizable monomer in the radically polymerizable component is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and may be 100% by weight.

[0048] The radical polymerizable monomer is preferably a low molecular weight compound because it can reduce 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.

[0049] Examples of radical polymerizable monomers 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 a (meth)acryloyl group.

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

[0051] di(meth)acrylates having an aliphatic ring, such as tricyclodecanedimethylol di(meth)acrylate, 1,4-cyclohexanedimethylol di(meth)acrylate, norbornanedimethylol 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, and 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.

[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, and ethylenebis(meth)acrylamide.

[0053] The monofunctional (meth)acrylate compound is not particularly limited, but 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; 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 diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, tripropylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate; 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 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.

[0056] In one embodiment, the radical polymerizable compound, particularly the radical polymerizable monomer, preferably has an aliphatic structure. The aliphatic structure is a structure formed from a saturated carbon-carbon bond that does not contain an aromatic carbon. For example, the radical polymerizable monomer may have an ethylenically unsaturated bond and an aliphatic structure that are directly or via -(CH2) nThe aliphatic structure may be a compound bonded via a linking group selected from the group consisting of - (n is an integer selected from 1 to 10), -O-, -COO-, -CO-, -OCO-, and combinations thereof. 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 may be formed solely from an aliphatic ring. Although not particularly limited, the radical polymerizable compound, particularly the radical polymerizable monomer, preferably contains 2 to 5 aliphatic rings, more preferably 2 to 3 aliphatic rings. The radical polymerizable compound, particularly the radical polymerizable monomer, may contain a crosslinked condensed ring, and the crosslinked condensed ring may contain multiple aliphatic rings. For example, the radical polymerizable compound, particularly the radical 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 radical polymerizable compound, particularly the radical polymerizable monomer, the content of the radical polymerizable compound 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 radical polymerizable compound, particularly the radical polymerizable monomer, the content of the radical polymerizable compound 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, the radical polymerizable compound preferably has no reactive groups other than the ethylenically unsaturated bond. In particular, it is preferable that the radical polymerizable monomer does not contain a hydroxy 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 hydroxy 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 even be 0% by weight.

[0060] Examples of radically polymerizable oligomers and polymers include those having an ethylenically unsaturated bond at the end of the oligomer or polymer, particularly those having a (meth)acryloyl group at the end of the oligomer or polymer (e.g., urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate).

[0061] The weight ratio of the cationically polymerizable component to the radically polymerizable component in the adhesive composition (cationically polymerizable component / radical polymerizable component) 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 70% by weight or more, more preferably 80% by weight or more, and particularly preferably 90% by weight or more. There is no particular upper limit to the total content of the cationically polymerizable component and the radically polymerizable component in the adhesive composition, but the total content may be, for example, 99.9% by weight or less.

[0063] As described above, the radical polymerizable component can contain various constituents, but it contains at least a polyfunctional alicyclic (meth)acrylate. This alicyclic (meth)acrylate is a polyfunctional (meth)acrylate having at least two (meth)acryloyl groups. The alicyclic (meth)acrylate may be any of a radical polymerizable monomer, a radical polymerizable oligomer, and a radical polymerizable polymer, but is preferably a radical polymerizable monomer.

[0064] The alicyclic (meth)acrylate preferably contains 2 to 5 aliphatic rings, more preferably 2 to 3 aliphatic rings. The alicyclic (meth)acrylate may contain a crosslinked condensed ring, and the crosslinked condensed ring may contain multiple aliphatic rings. For example, the alicyclic (meth)acrylate 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, more preferably 4 to 10.

[0065] In the alicyclic (meth)acrylate, the (meth)acryloyloxy group may be directly bonded to the aliphatic ring, or the (meth)acryloyloxy group may be bonded to the aliphatic ring via a linking group. n - (n is an integer selected from 1 to 10), -O-, -COO-, -CO-, -OCO-, etc., and an alkylene group (-(CH2) n In the alkylene group (-(CH2)), n is preferably 1 to 6, more preferably 1 to 4, and particularly preferably 1 or 2. When the number of carbon atoms is 2 or more, ... and particularly preferably 1 or 2. When the number of carbon atoms is 2 or more, n is preferably 1 to 6, n A linking group such as -O-, -COO-, -CO-, or -OCO- may be inserted between the carbon-carbon bonds of (-).

[0066] In the radical polymerizable component, the content of the polyfunctional alicyclic (meth)acrylate is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and may be 100% by weight.

[0067] 3. Isocyanate compounds The adhesive composition containing an isocyanate compound can improve peel strength and further improve solvent resistance of the adhesive composition.

[0068] 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.

[0069] The isocyanate compound is not particularly limited, and various aromatic, aliphatic, and alicyclic isocyanate compounds can be used. Examples of monofunctional isocyanate compounds include ethyl isocyanate, propyl isocyanate, cyclohexyl isocyanate, and phenyl isocyanate. 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.

[0070] In this specification, the term "isocyanate compound" encompasses not only isocyanate compounds but also derivatives formed from isocyanate compounds, unless otherwise specified. Derivatives of isocyanate compounds are compounds in which an isocyanate group is converted to an isocyanurate bond, a biuret bond, a urethane bond, an allophanate bond, a urea bond, or a uretdione bond through a chemical reaction. Compounds containing an isocyanurate bond are particularly preferred because they are highly effective in improving adhesion to an adherend and can improve room-temperature peel strength and electrolyte resistance. The number of isocyanate groups contained in the derivative is at least one, and derivatives in which two or more isocyanate groups remain unreacted are particularly preferred.

[0071] The derivative may be formed from two or more of the same or different isocyanate compounds. Specific examples of such isocyanate compound derivatives include multimers of polyfunctional isocyanate compounds. Multimers of isocyanate compounds may be formed via the above-mentioned bonds, such as uretdione bonds, isocyanurate bonds, and allophanate bonds. The isocyanate compounds forming the multimer are usually all the same type of isocyanate compound, but they may be different types of isocyanate compounds. The use of multimers formed from different types of isocyanate compounds may improve the peel strength of the adhesive composition. The number of 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 formed from a polyfunctional isocyanate compound.

[0072] When present, the total amount of isocyanate compounds and derivatives thereof 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.

[0073] 4. Polymerization initiator The adhesive composition includes a cationic polymerization initiator, which may be selected from the group consisting of photocationic polymerization initiators and thermal cationic polymerization initiators.

[0074] The cationic photopolymerization initiator generates cationic species or Lewis acids upon irradiation with active energy rays such as visible light, ultraviolet light, X-rays, and electron beams, and initiates the polymerization reaction of cationically polymerizable components such as epoxy groups and oxetanyl groups.

[0075] The incorporation of a cationic photopolymerization initiator enables curing at room temperature and provides excellent adhesion to adherends such as metals and resins. Furthermore, because the cationic photopolymerization initiator acts catalytically upon irradiation with active energy rays, it offers excellent storage stability and workability even when mixed with a cationic polymerizable component. Examples of cationic photopolymerization 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-allene complexes.

[0076] Examples of aromatic diazonium salts include the following compounds: benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, Benzenediazonium hexafluoroborate, etc.

[0077] Examples of aromatic iodonium salts include the following compounds: diphenyliodonium tetrakis(pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, Di(4-nonylphenyl)iodonium hexafluorophosphate, etc.

[0078] Examples of 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-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.

[0079] Examples of iron-allene complexes include the following compounds: Xylene-cyclopentadienyl iron(II) hexafluoroantimonate, Cumene-cyclopentadienyliron(II) hexafluorophosphate, Xylene-cyclopentadienyliron(II)-tris(trifluoromethylsulfonyl)methanide, etc.

[0080] These cationic photopolymerization initiators may be used singly 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 region of 300 nm or more, and therefore can provide cured products with excellent curability and good mechanical strength and adhesive strength.

[0081] The cationic photopolymerization initiator is readily available as a commercially available product, and examples thereof include, by trade name, "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 Co., Ltd.), "CPI-10 Examples of suitable cationic surfactants include "UVI-6992" manufactured by The Dow Chemical Company, and "CPI-100P", "CPI-101A", "CPI-200K", and "CPI-210S" (all manufactured by San-Apro Ltd.), which contain diphenyl[4-(phenylthio)phenyl]sulfonium as a cationic component. Particularly preferred are "UVI-6992" manufactured by The Dow Chemical Company, and "CPI-100P", "CPI-101A", "CPI-200K", and "CPI-210S" manufactured by San-Apro Ltd.

[0082] A thermal cationic polymerization initiator is activated by heating and induces ring-opening polymerization of a cationic polymerizable group contained in a cationic polymerizable compound such as an epoxy compound or an oxetane compound. Examples of the thermal cationic polymerization initiator include benzylsulfonium salts, thiophenium salts, thioranium salts, benzylammonium salts, pyridinium salts, hydrazinium salts, carboxylic acid esters, sulfonic acid esters, and amine imides. These thermal cationic polymerization initiators are readily available commercially, and examples of such initiators include "ADEKAOPTON CP77" and "ADEKAOPTON CP66" (both manufactured by ADEKA Corporation), "CI-2639" and "CI-2624" (both manufactured by Nippon Soda Co., Ltd.), and "SAN-AID SI-60L," "SAN-AID SI-80L," and "SAN-AID SI-100L" (all manufactured by Sanshin Chemical Industry Co., Ltd.).

[0083] The adhesive composition may contain a radical polymerization initiator in addition to the cationic polymerization initiator. A photoradical polymerization initiator is preferred as the radical polymerization initiator. The photoradical polymerization initiator generates radical species upon irradiation with active energy rays such as visible light, ultraviolet light, X-rays, and electron beams, and initiates a polymerization reaction of the radically polymerizable compound.

[0084] Specific examples of the photoradical polymerization initiator are not particularly limited, but include the following compounds:

[0085] 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, methyl o-benzoylbenzoate, 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 photoinitiators such as 1,2-octanedione, 1-[4-(phenylthiophenyl)]-, 2-(O-benzoyloxime); Camphorquinone, etc.

[0086] The polymerization initiator can be used alone or in combination of two or more depending on the desired performance. The content of the polymerization initiator in the adhesive composition is preferably 0.1 to 10 wt %, more preferably 0.5 to 5 wt %, and particularly preferably 1 to 3 wt %. When the amount of the polymerization initiator is within these ranges, the adhesive strength of the adhesive composition can be increased.

[0087] Alicyclic (meth)acrylates contained in the radically polymerizable component tend to have a high storage modulus even without a high degree of polymerization. Therefore, to maintain the storage modulus within an appropriate range and improve adhesive strength, it is preferable to reduce the content of the radical polymerization initiator. The content of the radical polymerization initiator in the adhesive composition is preferably 6 wt% or less, more preferably 4 wt% or less, even more preferably 2 wt% or less, and particularly preferably 1 wt% or less, and may even be 0.5 wt% or less. The radical polymerization initiator is an optional component and does not necessarily need to be added. Alicyclic (meth)acrylates can be cured well using the radicals generated in trace amounts by the cationic polymerization initiator, even without the radical polymerization initiator. Furthermore, the addition of a radical polymerization initiator can increase the curing reaction rate and internal stress, and reducing the amount of radical initiator can improve adhesive strength.

[0088] 5. Other ingredients Furthermore, the adhesive composition may optionally contain other components different from the above components, provided that the effects of the present invention are not impaired.

[0089] Other components include hydroxyl-containing compounds such as water and alcohols. Alcohols are preferably compounds with multiple hydroxyl groups, and compounds with 2 to 4 hydroxyl groups are preferred. Specific alcohols include aliphatic alcohols with 2 to 6 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, and glycerin. Water is particularly preferred as the hydroxyl-containing compound from the viewpoint of improving adhesive strength. When present, the content of the hydroxyl-containing compound in the adhesive composition is preferably 0.05 to 5 wt %, more preferably 0.5 to 4 wt %, and particularly preferably 0.8 to 3 wt %. The water content in the adhesive composition can be measured by Karl Fischer titration in accordance with JIS K 0113 (2005).

[0090] Another type of other component is a photosensitizer. The incorporation of a photosensitizer improves reactivity and can improve the mechanical strength and adhesive strength of the cured product. Examples of photosensitizers include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreducible dyes.

[0091] Specific photosensitizers are not particularly limited, and examples thereof 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; Other examples include α,α-diethoxyacetophenone, benzil, fluorenone, xanthone, uranyl compounds, and halogen compounds.

[0092] 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 combination of two or more.

[0093] The photosensitizer is preferably contained in an amount of 0.1 to 20 parts by weight, based on 100 parts by weight of the total amount of cationically polymerizable components in the adhesive composition.

[0094] Polyols have the property of accelerating cationic polymerization and can be blended into the adhesive composition. Preferred polyols are those that do not contain acidic groups other than phenolic hydroxyl groups, and examples thereof include polyol compounds that do not contain functional groups other than hydroxyl groups, polyester polyol compounds, polycaprolactone polyol compounds, polyol compounds that contain phenolic hydroxyl groups, and polycarbonate polyol compounds.

[0095] Furthermore, as long as the effects of the present invention are not impaired, a silane coupling agent, an ion trapping agent, an antioxidant, a light stabilizer, a chain transfer agent, a sensitizer, a tackifier, a thermoplastic resin, a filler, a flow adjuster, a plasticizer, an antifoaming agent, a leveling agent, a dye, a solvent, etc. may also be blended.

[0096] 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, the adhesive composition can be easily applied. 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.

[0097] In this embodiment, the adhesive composition preferably has a reduced solvent content. 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 less. The solvent content 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. The adhesive composition may not contain a solvent.

[0098] 6. 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 components of the adhesive composition used, the substrate, the purpose, etc., but is preferably 30 to 80°C.

[0099] The viscosity of the adhesive composition at 25° C. is preferably 10 to 1,000 mPa·s in terms of excellent coatability onto substrates.

[0100] The storage modulus of the cured product of the adhesive composition at 25°C is preferably 2000 MPa or more, more preferably 2500 MPa or more, and particularly preferably 2800 MPa or more. The storage modulus of the cured product at 25°C is preferably 4000 MPa or less, more preferably 3500 MPa or less, and particularly preferably 3300 MPa or less. When the storage modulus of the cured product at 25°C falls within these ranges, the peel strength at high temperatures is improved.

[0101] The storage modulus of the cured product of the adhesive composition at 80°C is preferably 100 MPa or more, more preferably 200 MPa or more, and particularly preferably 300 MPa or more. The storage modulus of the cured product at 80°C is preferably 1000 MPa or less, more preferably 800 MPa or less, and particularly preferably 750 MPa or less. When the storage modulus of the cured product at 80°C falls within these ranges, the peel strength at high temperatures is improved.

[0102] The storage modulus of the cured product of the adhesive composition at 120°C is preferably 10 MPa or more, more preferably 50 MPa or more, and particularly preferably 100 MPa or more. The storage modulus of the cured product at 80°C is preferably 500 MPa or less, more preferably 300 MPa or less, and particularly preferably 250 MPa or less. When the storage modulus of the cured product at 120°C falls within these ranges, the peel strength at high temperatures is improved.

[0103] The storage modulus of the adhesive composition can be measured by the following method. A cycloolefin polymer film (0.1 mmt x 100 mm x 150 mm, ZF-14-100 manufactured by Zeon Corporation) and a 5 x 50 mm cutout of silicone rubber (0.5 mmt x 90 mm x 140 mm) are placed in that order on a glass plate (1.6 mmt x 120 mm x 170 mm). The cutout is filled with the adhesive composition, and the plate is sandwiched between cycloolefin polymer films of the same size to prevent air bubbles from forming. A glass plate of the same size is then placed on top, and the plate is clamped and fixed on all four sides with clips. A high-pressure mercury lamp is used, and the temperature is 50 mW / cm. 2 The adhesive is temporarily cured by irradiating each side with UV for 30 seconds. Next, the temporarily cured adhesive is removed from the mold and irradiated with 50mW / cm 2 The adhesive is cured by directly irradiating the front and back sides with UV light for 2 minutes, then burrs are removed and strip-shaped test specimens measuring 0.5mm x 5mm x 50mm are prepared. The test specimens are then left in an environment of 23°C x 55% RH for at least 24 hours to condition them before being used to measure dynamic viscoelasticity. Using a Hitachi High-Tech Science DMS6100, measurements are taken from at least -20°C to 130°C at a heating rate of 2°C / min and a frequency of 1Hz, and the storage modulus is confirmed at each temperature.

[0104] 7.How to use The adhesive composition of the present invention can be used for bonding resins, and can be used for bonding resins to resins. The adhesive composition of the present invention can be used for bonding metals, and can be used for bonding metals to metals. Furthermore, the adhesive composition of the present invention can also be used for bonding different materials, such as metal and resin. Specific examples of usage 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. As such, the adhesive composition may be active energy ray-curable or heat-curable, but active energy ray-curable adhesive compositions are particularly preferred.

[0105] 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. Among these, polyolefin is particularly preferred. The resin to be bonded is preferably processed into a film, and particularly preferably a non-stretched resin film.

[0106] Specific examples of metals include gold, silver, copper, aluminum, iron, nickel, titanium, stainless steel, chrome molybdenum steel, etc. The metal to be bonded is preferably processed into a metal plate, a metal flat plate, a metal foil, or the like.

[0107] Coating onto the substrate may be carried out according to a conventionally known method, and examples thereof include methods using 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.

[0108] Examples of active energy rays include visible light, ultraviolet light, X-rays, and electron beams, but ultraviolet light is preferred because inexpensive equipment can be used.

[0109] When curing with ultraviolet light, various light sources can be used, including 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 irradiation dose of ultraviolet light is 200 to 2,000 mJ / cm in the UV-A region (near 365 nm). 2 It is preferable that the concentration is 300 to 1,500 mJ / cm 2 is more preferred.

[0110] When curing with electron beams, various electron beam irradiation devices can be used, such as Cockcroft-Wartsin, Van de Graaff, and resonant transformer devices. 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 within a 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 preferred. The oxygen concentration of the electron beam irradiation atmosphere is preferably 500 ppm or less, more preferably 300 ppm or less.

[0111] 8.Heat-sealable materials The adhesive composition can be used to produce a heat-sealable member. The heat-sealable member 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-sealable resin layer bonded to the other side of the adhesive layer.

[0112] Schematic diagrams of heat-sealable members are shown in Figures 1 and 2. That is, the heat-sealable member 1 in Figure 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 Figure 2 sequentially comprises a heat-sealable resin layer 11, an adhesive layer 12, a metal layer 13, and another layer 14.

[0113] The shape of the heat-sealable member may be appropriately determined depending on the application, etc., and is not particularly limited, but examples thereof include a film, a sheet, a plate, etc.

[0114] The heat-sealable resin layer is a layer containing a resin that melts with heat and can fuse the material constituting one layer with the material constituting the other layer. The 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, preferred polyolefin resins are polyethylene and polypropylene. In particular, when the heat-sealable member is used to integrate with other members, the resin is preferably unstretched because it causes little dimensional change (shrinkage), and unstretched polyethylene and unstretched polypropylene are more preferred.

[0115] The above-mentioned heat-fusible resin layer may be a layer containing additives such as a lubricant, a filler, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a flame retardant, a colorant, a dispersant, and an adhesion imparting agent, as necessary.

[0116] The thickness of the heat-sealable resin layer is not particularly limited and depends on the resin material, etc., but for example, when 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.

[0117] The 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, and particularly preferably 2 μm to 10 μm. If the thickness of the adhesive layer is 1 μm to 20 μm, the heat-fusible member can be easily processed, for example, by bending, when it is in the form of a sheet.

[0118] 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 because of 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.

[0119] 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 to protect the metal layer. 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-sealable composite product is made into a sealed container or the like. The other layer may have a multilayer 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, particularly preferably 30 μm to 50 μm.

[0120] When the heat-sealable member is used in a lithium-ion battery packaging material, the adhesive performance can be maintained even if there are temperature changes in the battery storage or usage environment, and in particular, the adhesive performance can be maintained in a temperature range higher than normal temperature in summer or inside a car, and lower than the ambient temperature in cold regions, due to the chemical temperature increase in the battery constituent materials that accompanies charging or discharging.

[0121] 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 together, and then irradiated with active energy rays.

[0122] (2) A method in which an adhesive composition is applied to the surface of a heat-fusible 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, pressed together, and then irradiated with active energy rays.

[0123] 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 a 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, pressed together, and irradiated with active energy rays.

[0124] (4) A method in which an adhesive composition is applied to the surface of a heat-fusible 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 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, etc., and pressed together, and then irradiated with active energy rays.

[0125] (5) A method in which a film for forming another layer 14 is extruded onto the surface of the metal layer 13 in the laminate obtained by the above method (1) or (2).

[0126] The adhesive composition is often applied to a material for forming a metal layer, such as a metal foil, or to the surface of a metal layer in a composite film comprising a metal layer and another layer (a resin layer), but is not particularly limited thereto. When a metal foil is used, 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 that is less susceptible to breakage. When a composite film is used, it is preferable that the metal layer contains aluminum and that the other layer (the resin layer) contains a polyamide resin, a polyester resin, or the like. Furthermore, when producing the heat-sealable member shown in FIG. 2 without using a composite film, i.e., when using the method (5) above, it is preferable to use a film containing a polyamide resin, a polyester resin, or the like as the film for forming the other layer 14.

[0127] Examples of heat-sealable resin films include polyolefin resin films, polyamide resin films, and polyester resin films. These resin films can be obtained by film-forming methods such as extrusion, cast molding, T-die molding, and inflation. The thickness of the heat-sealable resin film is usually 10 to 200 μm.

[0128] 9. Packaging materials for energy storage devices The heat-sealable member can be used in various industrial product fields, including the electrical, automotive, industrial, and other fields. The heat-sealable member is particularly preferably used as a packaging material for an electricity storage device, due to its high hot peel strength, excellent adhesiveness, and high electrolyte resistance. Examples of electricity storage devices for which the packaging material for an electricity storage device can be used include secondary batteries such as lithium-ion batteries and lithium-ion polymer batteries. [Example]

[0129] EXAMPLES The present invention will be explained in more detail below by showing examples and comparative examples, but the present invention is not limited to these examples.

[0130] (Preparation of Adhesive Composition) The components shown in the table below were blended in the amounts shown in the table for each example, and mixed by stirring to prepare adhesive compositions. Details of the abbreviations used in the table are as follows. The amount of each component in the table represents the weight ratio, and blank spaces mean that the component was not used. <Cationic polymerizable compound> Epogose BD: 1,4-butanediol diglycidyl ether, "Epogose BD(D)" manufactured by Yokkaichi Chemical Co., Ltd. Epogose HD: 1,6-hexanediol diglycidyl ether, "Epogose HD" manufactured by Yokkaichi Chemical Co., Ltd. jER1004: Bisphenol A type solid epoxy resin, "jER 1004" manufactured by Mitsubishi Chemical Corporation Celloxide 2021P: 3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexanecarboxylate, manufactured by Daicel Corporation "Celloxide 2021P" R-45EPT: Polybutadiene diglycidyl ether, "Denalex 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. <Radical polymerizable compound> Light Acrylate DCP-A: Tricyclodecanedimethylol diacrylate, "Light Acrylate DCP-A" manufactured by Kyoeisha Chemical Co., Ltd. Light Acrylate 1,9ND-A: 1,9-nonanediol diacrylate, "Light Acrylate 1,9ND-A" manufactured by Kyoeisha Chemical Co., Ltd. Light Ester MPD-A: 3-methyl-1,5 pentanediol diacrylate, "Light Acrylate MPD-A" manufactured by Kyoeisha Chemical Co., Ltd. ·LA: Lauryl acrylate Light Acrylate IBX-A: Isobornyl acrylate, "Light Acrylate IB-XA" manufactured by Kyoeisha Chemical Co., Ltd. <Other ingredients> BHT: 2,6-di-tert-butyl-p-cresol, "BHT" manufactured by Nikki Universal Co., Ltd. CPI-110P: Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluorophosphate, manufactured by San-Apro Co., Ltd. "CPI-110P" Omnirad 184D: 1-hydroxycyclohexyl phenyl ketone, manufactured by IGM Resins.

[0131] (Preparation of test pieces for peel strength evaluation) An adhesive composition was applied to the chemically treated surface of a 40 μm thick aluminum foil that had been subjected to a chemical conversion treatment, and an 80 μm thick CPP (cast polypropylene) film that had been corona discharge treated was placed on top of it with the corona discharge treated surface facing the adhesive-coated surface. This laminated film was sandwiched between two sheets of copy paper on 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. Note that when measuring the peel strength, which will be performed later, no adhesive was applied to the part that would be clamped by the gripping tools of the tensile tester. The laminated film was removed, and then irradiated from the CPP film side of the laminated film with a conveyor-type ultraviolet irradiation device (high-pressure mercury lamp, UV-A region irradiation intensity 280 mW / cm) manufactured by iGraphics Co., Ltd. 2 , cumulative light intensity 600mJ / cm 2 The adhesive composition was cured by ultraviolet irradiation using a UV POWER PUCK II (all values ​​measured by Heraeus Co., Ltd.), and a test piece was prepared. The next day, the adhesive composition was cut into a 15 mm wide strip to prepare a test piece for evaluating peel strength.

[0132] (Peel strength measurement) Using a thermostatically controlled tensile testing machine (Shimadzu Corporation, Autograph AGS-X), a T-peel test was performed at a pulling rate of 100 mm / min until the gripper had traveled 100 mm, and the average peel strength from a travel distance of 40 mm to 100 mm was taken as the peel strength (N / 15 mm). The peel test was performed at three temperatures: room temperature (rt, 23°C), 80°C, and 120°C.

[0133] The results of the peel strength measurements are shown in Table 1 together with the formulation of the adhesive composition.

[0134] [Table 1]

[0135] The examples containing cycloaliphatic acrylate had higher peel strengths at all temperatures than the comparative examples without cycloaliphatic acrylate, demonstrating the effectiveness of using cycloaliphatic acrylate in the adhesive composition.

[0136] (Evaluation on other substrates) The adhesive composition used was the same as that used in Example 3. Test pieces for evaluating peel strength were prepared and evaluated in the same manner as in Example 3, except that the CPP film was changed to the film shown in the table below. The results are shown in the table below.

[0137] [Table 2] From the results in Tables 1 and 2, it can be said that the adhesive composition has excellent adhesion to polyolefins (excluding cycloolefin polymers), and in particular to polypropylene.

Claims

1. (1) at least one cationically polymerizable component selected from the group consisting of cationically polymerizable monomers, cationically polymerizable oligomers, and cationically polymerizable polymers; (2) at least one radically polymerizable component selected from the group consisting of radically polymerizable monomers, radically polymerizable oligomers, and radically polymerizable polymers; A curable adhesive composition comprising: the radical polymerizable component contains at least an alicyclic (meth)acrylate, and the alicyclic (meth)acrylate is a polyfunctional (meth)acrylate having at least two (meth)acryloyl groups; Contains a cationic polymerization initiator, A curable adhesive composition which may further contain a radical polymerization initiator as an optional component, provided that the content of the radical polymerization initiator in the curable adhesive composition is 4 wt % or less.

2. 2. The curable adhesive composition according to claim 1, wherein the total amount of the cationically polymerizable component and the radically polymerizable component is 80% by weight or more, and the ratio of the cationically polymerizable component to the radically polymerizable component is 20 / 80 to 70 / 30.

3. The curable adhesive composition according to claim 2 , wherein the content of the alicyclic (meth)acrylate in the radically polymerizable component is 80% by weight or more.

4. The curable adhesive composition according to claim 1 , wherein the content of the radical polymerization initiator in the curable adhesive composition is 0.5% by weight or less.

5. The curable adhesive composition according to claim 1, wherein the cationically polymerizable component comprises at least one selected from the group consisting of an aliphatic epoxy compound and an alicyclic epoxy compound.

6. 6. The curable adhesive composition according to claim 5, comprising the alicyclic epoxy compound, wherein the alicyclic epoxy compound is an epoxy monomer or epoxy oligomer containing an alicyclic group that forms an epoxide between two adjacent carbon atoms that constitute an aliphatic ring.

7. The aliphatic epoxy compound is an epoxy monomer or an epoxy oligomer having epoxy groups bonded to two or more ends of an aliphatic group, and the aliphatic group is —(CH ２ ) ｎ -, where n is an integer from 1 to 15, provided that -(CH ２ ) ｎ The curable adhesive composition according to claim 6, wherein at least one linking group selected from the group consisting of -O-, -COO-, -CO-, and -OCO- may be inserted between some of the carbon-carbon bonds.

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