Adhesive composition, laminate, packaging material, and packaging material for battery case

Abstract

An adhesive composition according to the present invention includes: a main agent containing a crystalline modified olefin polymer and an unmodified hydrogenated styrene-based elastomer; and a curing agent containing a crosslinking agent. The crystalline modified olefin polymer is obtained by modifying a crystalline C2-C20 α-olefin polymer by using a monomer having a functional group that is capable of reacting with an epoxy group, oxazoline group, or isocyanate group. The weight average molecular weight of the unmodified hydrogenated styrene-based elastomer is 10,000-80,000.

Description

Adhesive composition, laminate, packaging material, and packaging material for battery case

[0001] The present invention relates to an adhesive composition, a laminate, a packaging material, and a packaging material for battery cases; more specifically, to an adhesive composition, a laminate including an adhesive layer made of a dried product of the adhesive composition, a packaging material including the laminate, and a packaging material for battery cases including the packaging material.

[0002] In recent years, from the viewpoint of achieving thinner designs, lithium batteries have been used as batteries for personal computers, portable terminal devices, etc. The lithium batteries are sealed in, for example, packaging.

[0003] Such a packaging material can be obtained, for example, by bonding an aluminum foil layer and a polypropylene film with an adhesive.

[0004] As such an adhesive, for example, an adhesive composition containing a modified polyolefin and a styrene-ethylene-propylene-styrene resin (Kraton G1730, weight average molecular weight 93,000) has been proposed (see, for example, Example 7 of Patent Document 1).

[0005] International Publication No. 2019 / 188283 Pamphlet

[0006] On the other hand, adhesives used in packaging materials for lithium batteries are required to be resistant to electrolyte.

[0007] The present invention provides an adhesive composition having excellent electrolyte resistance, a laminate including an adhesive layer made of a dried product of the adhesive composition, a packaging material including the laminate, and a packaging material for battery cases including the packaging material.

[0008] The present invention [1] is an adhesive composition comprising a base agent containing a crystalline modified olefin polymer and an unmodified hydrogenated styrene-based elastomer, and a curing agent containing a crosslinking agent, wherein the crystalline modified olefin polymer is obtained by modifying a crystalline α-olefin polymer having 2 to 20 carbon atoms with a monomer having a functional group reactive with an epoxy group, an oxazoline group, or an isocyanate group, and the weight average molecular weight of the unmodified hydrogenated styrene-based elastomer is 10,000 or more and 80,000 or less.

[0009] The present invention [2] includes the adhesive composition according to the above [1], wherein the acid value of the base agent is 10 mgKOH / g or more and 30 mgKOH / g or less.

[0010] The present invention [3] includes the adhesive composition according to the above [1] or [2], wherein the crystalline α-olefin polymer having 2 to 20 carbon atoms contains a structural unit derived from propylene.

[0011] The present invention [4] includes the adhesive composition according to the above [3], wherein the content of the propylene-derived structural units is 40 mol % or more and 95 mol % or less relative to the crystalline α-olefin polymer having 2 to 20 carbon atoms.

[0012] The present invention [5] includes the adhesive composition according to the above [4], wherein the crystalline polymer of an α-olefin having 2 to 20 carbon atoms comprises structural units derived from propylene and structural units derived from an α-olefin having 4 to 20 carbon atoms.

[0013] The present invention [6] includes the adhesive composition according to any one of the above [1] to [5], wherein the functional group is a carboxyl group or an acid anhydride group.

[0014] The present invention [7] includes the adhesive composition according to any one of the above [1] to [6], wherein the crosslinking agent is at least one selected from the group consisting of an epoxy compound, an oxazoline compound, and an isocyanate compound.

[0015] The present invention [8] includes the adhesive composition according to any one of the above [1] to [7], further comprising a catalyst, wherein the catalyst comprises an amine compound or a phosphine compound.

[0016] The present invention [9] comprises the adhesive composition according to any one of the above [1] to [8], wherein the content of the crystalline modified olefin polymer is 70 parts by mass or more and 95 parts by mass or less, relative to 100 parts by mass of the total amount of the crystalline modified olefin polymer and the unmodified hydrogenated styrene-based elastomer, and the content of the unmodified hydrogenated styrene-based elastomer is 5 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the total amount of the crystalline modified olefin polymer and the unmodified hydrogenated styrene-based elastomer.

[0017] The present invention

[10] includes a laminate including a first adhesive layer made of a dried product of the adhesive composition according to any one of the above [1] to [9] and a substrate, arranged in this order toward one side in the thickness direction.

[0018] The present invention

[11] includes a packaging material including an inner layer and the laminate described in the above

[10] in that order toward one side in the thickness direction.

[0019] The present invention

[12] includes a packaging material for a battery case, which comprises the packaging material according to the above

[11] , a second adhesive layer, and an outer layer, arranged in this order toward one side in the thickness direction.

[0020] The adhesive composition of the present invention contains an unmodified hydrogenated styrene elastomer having a weight average molecular weight of 10,000 or more and 80,000 or less, and therefore can improve resistance to electrolyte.

[0021] The laminate of the present invention includes a first adhesive layer made of a dried product of the adhesive composition of the present invention, which can improve electrolyte resistance.

[0022] The packaging material of the present invention includes the laminate of the present invention, and therefore can improve resistance to an electrolyte solution.

[0023] The battery case packaging material of the present invention includes the packaging material of the present invention, and therefore can improve electrolyte resistance.

[0024] Fig. 1 is a schematic diagram showing one embodiment of a laminate of the present invention. Fig. 2A and Fig. 2B show one embodiment of a method for producing a laminate of the present invention. Fig. 2A shows a first step of preparing a substrate. Fig. 2B shows a second step of arranging (forming) a first adhesive layer on the other surface in the thickness direction of the substrate. Fig. 3 is a schematic diagram showing one embodiment of a packaging material of the present invention. Fig. 4 is a schematic diagram showing one embodiment of a packaging material for a battery case of the present invention and a battery using this packaging material for a battery case.

[0025] The adhesive composition includes a base agent containing a crystalline modified olefin polymer and an unmodified hydrogenated styrene-based elastomer, and a curing agent containing a crosslinking agent.

[0026] <<Main Agent>> The main agent contains a crystalline modified olefin polymer and an unmodified hydrogenated styrene-based elastomer.

[0027] <Crystalline Modified Olefin Polymer> The crystalline modified olefin polymer is obtained by modifying a crystalline α-olefin polymer having 2 to 20 carbon atoms with a monomer having a functional group reactive with an epoxy group, an oxazoline group, or an isocyanate group.

[0028] [Crystalline α-olefin polymer having 2 to 20 carbon atoms] A crystalline α-olefin polymer having 2 to 20 carbon atoms is an olefin polymer containing structural units derived from an α-olefin having 2 to 20 carbon atoms, which can form a crystalline polymer. In other words, a crystalline α-olefin polymer having 2 to 20 carbon atoms is obtained by polymerizing an α-olefin having 2 to 20 carbon atoms. Note that crystalline is defined as a solid state at 23°C and having a melting point at which the heat of fusion is 1 J / g or more.

[0029] Examples of α-olefins having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

[0030] The crystalline α-olefin polymer having 2 to 20 carbon atoms preferably contains a structural unit derived from propylene, from the viewpoint of improving adhesive strength.

[0031] From the viewpoint of further improving adhesive strength, the crystalline α-olefin polymer having 2 to 20 carbon atoms more preferably contains structural units derived from propylene and structural units derived from an α-olefin having 4 to 20 carbon atoms. The crystalline α-olefin polymer having 2 to 20 carbon atoms is even more preferably composed of structural units derived from propylene and structural units derived from an α-olefin having 4 to 20 carbon atoms. In other words, the crystalline α-olefin polymer having 2 to 20 carbon atoms is even more preferably a propylene / α-olefin copolymer having 4 to 20 carbon atoms.

[0032] Furthermore, the crystalline α-olefin polymer having 2 to 20 carbon atoms particularly preferably comprises structural units derived from propylene and structural units derived from 1-butene. That is, the crystalline α-olefin polymer having 2 to 20 carbon atoms particularly preferably is a propylene / 1-butene copolymer.

[0033] The type and content of the structural unit derived from an α-olefin having 2 to 20 carbon atoms are selected so that the olefin polymer is crystalline.

[0034] Specifically, when a crystalline C2-C20 α-olefin polymer contains structural units derived from propylene and structural units derived from 1-butene, the content of the structural units derived from propylene is, for example, 40 mol% to 95 mol%, preferably 50 mol% to 80 mol%, and more preferably 60 mol% to 70 mol%, relative to the crystalline C2-C20 α-olefin polymer. Furthermore, the content of the structural units derived from 1-butene is, for example, 5 mol% to 60 mol%, preferably 20 mol% to 50 mol%, and more preferably 30 mol% to 40 mol%, relative to the crystalline C2-C20 α-olefin polymer.

[0035] When the content ratio of the structural unit derived from propylene and the content ratio of the structural unit derived from 1-butene are equal to or greater than the above lower limit and equal to or less than the above upper limit, the adhesive strength can be improved.

[0036] The above content ratio may be, for example, １３This can be confirmed by known means such as C-NMR measurement (the same applies below).

[0037] Crystalline α-olefin polymers having 2 to 20 carbon atoms can be obtained by, for example, the methods described in Japanese Patent No. 3939464 and International Publication No. 2004 / 87775. Specifically, crystalline α-olefin polymers having 2 to 20 carbon atoms can be obtained by polymerizing an α-olefin having 2 to 20 carbon atoms in the presence of a metallocene catalyst.

[0038] The heat of fusion of the crystalline α-olefin polymer having 2 to 20 carbon atoms, measured in accordance with JIS K7122, is, for example, 1 J / g to 50 J / g, preferably 10 J / g to 40 J / g, more preferably 20 J / g to 40 J / g, and even more preferably 20 J / g to 30 J / g.

[0039] When the heat of fusion is equal to or greater than the above lower limit and equal to or less than the above upper limit, the adhesive strength can be improved.

[0040] The melting point of the crystalline α-olefin polymer having 2 to 20 carbon atoms is, for example, 40°C to 100°C, preferably 50°C to 95°C, more preferably 60°C to 90°C, even more preferably 70°C to 90°C, and particularly preferably 70°C to 80°C.

[0041] The melting point can be measured by a differential scanning calorimeter (the same applies hereinafter).

[0042] The crystalline α-olefin polymer having 2 to 20 carbon atoms has a weight average molecular weight (polystyrene equivalent) measured by gel permeation chromatography (GPC) of, for example, 100,000 to 1,000,000, preferably 200,000 to 500,000, and more preferably 300,000 to 400,000.

[0043] The crystalline α-olefin polymers having 2 to 20 carbon atoms can be used alone or in combination of two or more kinds.

[0044] [Monomer] The monomer has a functional group that can react with an epoxy group, an oxazoline group, or an isocyanate group.

[0045] Such functional groups include, for example, a hydroxyl group, an amino group, a carboxyl group, an acid anhydride group, an ester group, and a thiol group.

[0046] The monomer is a compound having the above-mentioned functional group, and examples thereof include hydroxyl group-containing ethylenically unsaturated compounds, amino group-containing ethylenically unsaturated compounds, unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, vinyl ester compounds, and thiol group-containing ethylenically unsaturated compounds.

[0047] The hydroxyl group-containing ethylenically unsaturated compound has a hydroxyl group as the functional group. Examples of the hydroxyl group-containing ethylenically unsaturated compound include hydroxyl group-containing (meth)acrylic acid esters. Examples of the hydroxyl group-containing (meth)acrylic acid esters include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate.

[0048] The amino group-containing ethylenically unsaturated compound has an amino group as the functional group. Examples of the amino group-containing ethylenically unsaturated compound include aminomethyl (meth)acrylate and propylaminoethyl (meth)acrylate.

[0049] The unsaturated carboxylic acid has a carboxyl group as the functional group. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, norbornene dicarboxylic acid, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic acid.

[0050] The unsaturated carboxylic acid anhydride has an acid anhydride group as the functional group. Examples of the unsaturated carboxylic acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylic anhydride.

[0051] The vinyl ester compound has an ester group as the functional group, and examples of the vinyl ester compound include vinyl acetate, vinyl propionate, and vinyl n-butyrate.

[0052] The thiol group-containing ethylenically unsaturated compound has a thiol group as the functional group, and examples of the thiol group-containing ethylenically unsaturated compound include allyl mercaptan and 2-vinylbenzyl mercaptan.

[0053] The monomer preferably includes a carboxyl group-containing monomer and an acid anhydride group-containing monomer. That is, the functional group preferably includes a carboxyl group and an acid anhydride group. If the functional group is a carboxyl group or an acid anhydride group, the adhesive strength can be improved.

[0054] More preferably, the monomer is an unsaturated carboxylic acid anhydride, and even more preferably, the monomer is maleic anhydride.

[0055] The monomers can be used alone or in combination of two or more kinds.

[0056] [Production of Crystalline Modified Olefin Polymer] The crystalline modified olefin polymer can be obtained by modifying a crystalline α-olefin polymer having 2 to 20 carbon atoms with a monomer.

[0057] To modify a crystalline α-olefin polymer having 2 to 20 carbon atoms with a monomer, for example, the crystalline α-olefin polymer having 2 to 20 carbon atoms is first dissolved in a known organic solvent (for example, toluene).

[0058] Next, the monomer and the radical polymerization initiator are added, and the mixture is heated and stirred.

[0059] The modification amount (introduction amount) of a monomer in a crystalline polymer of an α-olefin having 2 to 20 carbon atoms, i.e., the content ratio of structural units derived from the monomer in a crystalline polymer of an α-olefin having 2 to 20 carbon atoms, is, for example, 0.1% by mass to 5.0% by mass, preferably 0.4% by mass to 3.0% by mass, more preferably 0.6% by mass to 2.0% by mass, even more preferably 1.0% by mass to 1.8% by mass, particularly preferably 1.2% by mass to 1.5% by mass, and most preferably 1.3% by mass to 1.4% by mass, relative to the crystalline polymer of an α-olefin having 2 to 20 carbon atoms.

[0060] Specifically, the modification amount (introduction amount) of the monomer in the crystalline α-olefin polymer having 2 to 20 carbon atoms is, from the viewpoint of heat resistance, for example, 0.1 mass% or more, preferably 0.4 mass% or more, more preferably 0.6 mass% or more, even more preferably 1.0 mass% or more, particularly preferably 1.2 mass% or more, and most preferably 1.3 mass% or more, and from the viewpoint of pot life, for example, 5.0 mass% or less, preferably 3.0 mass% or less, more preferably 2.0 mass% or less, even more preferably 1.8 mass% or less, particularly preferably 1.5 mass% or less, and most preferably 1.4 mass% or less.

[0061] The above-mentioned modification amount is, for example, １ This can be confirmed by known means such as H-NMR measurement (the same applies below).

[0062] Examples of the radical polymerization initiator include organic peroxides and organic peresters.

[0063] Examples of organic peroxides include dicumyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate)hexyne-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxide)hexane, and tert-butyl peroxybenzoate. Examples of organic peresters include tert-butyl peracetate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl persec-octoate, tert-butyl perpivalate, cumyl perpivalate, tert-butyl perdiethyl acetate, etc. Furthermore, examples of radical polymerization initiators include other azo compounds such as azobis-isobutylnitrile and dimethylazoisobutylnitrile.

[0064] As the radical polymerization initiator, preferably, an organic peroxide is used, and more preferably, di-tert-butyl peroxide is used.

[0065] The mixing ratio of the radical polymerization initiator is, for example, 0.001 to 10 parts by mass with respect to 100 parts by mass of the crystalline α-olefin polymer having 2 to 20 carbon atoms.

[0066] The radical polymerization initiators can be used alone or in combination of two or more kinds.

[0067] The heating temperature is, for example, 50° C. to 250° C., preferably 80° C. to 200° C., and more preferably 120° C. to 180° C. The reaction time is, for example, 1 minute to 10 hours.

[0068] In this way, the crystalline α-olefin polymer having 2 to 20 carbon atoms is modified with the monomer, and a crystalline modified olefin polymer (a crystalline modified olefin polymer varnish) is obtained.

[0069] The weight average molecular weight (polystyrene equivalent) of the crystalline modified olefin polymer measured by GPC is, for example, 500,000 to 500,000, preferably 80,000 to 300,000, more preferably 100,000 to 150,000, even more preferably 110,000 to 130,000, and particularly preferably 115,000 to 125,000.

[0070] The melting point of the crystalline modified olefin polymer is, for example, 40°C to 100°C, preferably 70°C to 90°C, and more preferably 70°C to 80°C.

[0071] The heat of fusion of the crystalline modified olefin polymer, measured in accordance with JIS K7122, is, for example, 1 J / g to 50 J / g, preferably 10 J / g to 45 J / g, more preferably 20 J / g to 40 J / g, and even more preferably 22 J / g to 30 J / g.

[0072] When the heat of fusion is equal to or greater than the above lower limit and equal to or less than the above upper limit, the adhesive strength can be improved.

[0073] The content of the crystalline modified olefin polymer is, for example, 70 parts by mass to 95 parts by mass, preferably 75 parts by mass to 85 parts by mass, per 100 parts by mass of the total amount of the crystalline modified olefin polymer and the unmodified hydrogenated styrene-based elastomer.

[0074] The content of the crystalline modified olefin polymer relative to the base resin is, for example, 70 to 95% by mass, or preferably 75 to 85% by mass.

[0075] The content of the crystalline modified olefin polymer relative to the adhesive composition is, for example, 70 to 95% by mass, or preferably 75 to 85% by mass.

[0076] When the content of the crystalline modified olefin polymer is equal to or more than the above lower limit and equal to or less than the above upper limit, the electrolyte resistance can be improved.

[0077] The crystalline modified olefin polymers may be used alone or in combination of two or more kinds.

[0078] <Unmodified hydrogenated styrene-based elastomer> The unmodified hydrogenated styrene-based elastomer is a polymer containing structural units derived from hydrogenated styrene. Specifically, the unmodified hydrogenated styrene-based elastomer contains only structural units derived from hydrogenated styrene and structural units derived from an α-olefin having 2 to 20 carbon atoms, and does not contain structural units derived from the above monomers.

[0079] Specific examples of the unmodified hydrogenated styrene elastomer include hydrogenated styrene-ethylene-butene-styrene copolymer and hydrogenated styrene-ethylene-propylene-styrene copolymer. From the viewpoint of adhesive strength, hydrogenated styrene-ethylene-butene-styrene copolymer is preferred as the unmodified hydrogenated styrene elastomer.

[0080] Commercially available unmodified hydrogenated styrene elastomers may also be used, such as Kraton G1726VS (hydrogenated styrene-ethylene-butene-styrene copolymer, manufactured by Kraton Corporation) and Septon 2002NT (hydrogenated styrene-ethylene-propylene-styrene copolymer, manufactured by Kuraray Co., Ltd.).

[0081] The weight average molecular weight (polystyrene equivalent) of the unmodified hydrogenated styrene elastomer measured by GPC is 10,000 to 80,000, preferably 30,000 to 60,000, more preferably 45,000 to 55,000, and even more preferably 48,000 to 53,000.

[0082] Specifically, the weight average molecular weight of the unmodified hydrogenated styrene-based elastomer is 10,000 or more, preferably 30,000 or more, more preferably 45,000 or more, even more preferably 48,000 or more, and is 80,000 or less, preferably 60,000 or less, more preferably 55,000 or less, even more preferably 53,000 or less.

[0083] When the weight average molecular weight of the unmodified hydrogenated styrene elastomer is equal to or greater than the lower limit, the electrolyte resistance is improved.

[0084] On the other hand, if the weight average molecular weight of the unmodified hydrogenated styrene elastomer is less than the lower limit, the electrolyte resistance decreases.

[0085] Furthermore, when the weight average molecular weight of the unmodified hydrogenated styrene elastomer is equal to or less than the upper limit, the electrolyte resistance is improved.

[0086] On the other hand, if the weight average molecular weight of the unmodified hydrogenated styrene elastomer exceeds the upper limit, the electrolyte resistance decreases.

[0087] The method for measuring the weight average molecular weight will be described in detail in the Examples below.

[0088] In the unmodified hydrogenated styrene elastomer, the content of the six-membered ring component as a monomer is, for example, 35 mass % or less.

[0089] When the content of the six-membered ring component is equal to or less than the upper limit, the compatibility tends not to decrease.

[0090] The content of the unmodified hydrogenated styrene-based elastomer is, for example, 5 parts by mass to 30 parts by mass, or preferably 15 parts by mass to 25 parts by mass, per 100 parts by mass of the total amount of the crystalline modified olefin polymer and the unmodified hydrogenated styrene-based elastomer.

[0091] The content of the unmodified hydrogenated styrene-based elastomer relative to the base resin is, for example, 5% by mass to 30% by mass, or preferably 15% by mass to 25% by mass.

[0092] The content of the unmodified hydrogenated styrene elastomer relative to the adhesive composition is, for example, 5% by mass to 30% by mass, or preferably 15% by mass to 25% by mass.

[0093] When the content of the unmodified hydrogenated styrene elastomer is equal to or greater than the above lower limit and equal to or less than the above upper limit, the electrolyte resistance can be improved.

[0094] The unmodified hydrogenated styrene elastomers can be used alone or in combination of two or more kinds.

[0095] <Other Resins> The base resin may also contain other resins.

[0096] Other resins include amorphous modified olefin polymers and unmodified olefin polymers.

[0097] The content of the other resin relative to the base resin is, for example, 10% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, and even more preferably 0% by mass. That is, more preferably, the base resin does not contain any other resin and is composed of a crystalline modified olefin polymer and an unmodified hydrogenated styrene-based elastomer.

[0098] The other resins may be used alone or in combination of two or more kinds.

[0099] <Preparation of Base Component> To prepare the base component, a crystalline modified olefin polymer, an unmodified hydrogenated styrene-based elastomer, and other resins that may be blended as required are mixed together.

[0100] The base agent can also be diluted with a known organic solvent (for example, a mixed solvent of methylcyclohexane and ethyl acetate).

[0101] When the base agent is diluted, the solid content concentration is, for example, 10% by mass to 60% by mass, or preferably 15% by mass to 40% by mass.

[0102] The acid value of the base agent (solid matter) is, for example, 1 mgKOH / g to 40 mgKOH / g, preferably 10 mgKOH / g to 30 mgKOH / g, and more preferably 13 mgKOH / g to 25 mgKOH / g.

[0103] Specifically, the acid value of the base agent is, for example, 1 mgKOH / g or more, preferably 10 mgKOH / g or more, more preferably 13 mgKOH / g or more, from the viewpoint of heat resistance, and is 40 mgKOH / g or less, preferably 30 mgKOH / g or less, more preferably 25 mgKOH / g or less, from the viewpoint of pot life.

[0104] The method for measuring the acid value will be described in detail in the Examples below.

[0105] <<Curing Agent>> The curing agent includes a crosslinking agent. The curing agent is preferably made of a crosslinking agent. <Crosslinking Agent> The crosslinking agent is preferably at least one selected from the group consisting of an epoxy compound, an oxazoline compound, and an isocyanate compound.

[0106] Examples of epoxy compounds include bisphenol-type epoxy resins (e.g., bisphenol A-type epoxy resins, bisphenol F-type epoxy resins), novolac-type epoxy resins (e.g., phenol novolac-type epoxy resins, cresol novolac-type epoxy resins), aliphatic-type epoxy resins, alicyclic-type epoxy resins, hydrogenated bisphenol-type epoxy resins, and amine-type epoxy resins. Preferred examples of epoxy compounds include novolac-type epoxy resins. More preferred examples of epoxy compounds include phenol novolac-type epoxy resins.

[0107] Examples of the oxazoline compound include an oxazoline group-containing polymer, such as a homopolymer of an oxazoline group-containing monomer and a copolymer of an oxazoline group-containing monomer and another monomer copolymerizable with the oxazoline group-containing monomer.

[0108] Examples of oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-2-oxazoline, and 2-isopropenyl-4,4-dimethyl-2-oxazoline.

[0109] Examples of other monomers copolymerizable with the oxazoline group-containing monomer include (meth)acrylic acid alkyl esters, unsaturated carboxylic acids (e.g., acrylic acid, methacrylic acid), unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile), unsaturated amides (e.g., (meth)acrylamide), vinyl esters (e.g., vinyl acetate, vinyl propionate), vinyl ethers (e.g., methyl vinyl ether, ethyl vinyl ether), α-olefins (e.g., ethylene, propylene), and unsaturated aromatic monomers (e.g., styrene, α-methylstyrene).

[0110] The oxazoline compound is preferably a copolymer of an oxazoline group-containing monomer and another monomer copolymerizable with the oxazoline group-containing monomer, and more preferably an oxazoline group-containing polystyrene.

[0111] Examples of the isocyanate compound include alicyclic polyisocyanates, aliphatic polyisocyanates, aromatic polyisocyanates, araliphatic polyisocyanates, and derivatives thereof. Preferably, the isocyanate compound is aliphatic polyisocyanates and derivatives thereof.

[0112] Examples of aliphatic polyisocyanates include aliphatic diisocyanates. Examples of aliphatic diisocyanates include 1,6-hexamethylene diisocyanate (1,6-HDI), 1,5-pentamethylene diisocyanate (1,5-PDI), tetramethylene diisocyanate, trimethylene diisocyanate, 1,2-, 2,3-, or 1,3-butylene diisocyanate, and 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate. Preferably, 1,5-PDI is used as the aliphatic polyisocyanate.

[0113] Examples of the derivatives of aliphatic polyisocyanates include isocyanurate derivatives, allophanate derivatives, polyol derivatives, biuret derivatives, urea derivatives, oxadiazinetrione derivatives, carbodiimide derivatives, uretdione derivatives, and uretonimine derivatives of the above-mentioned aliphatic polyisocyanates.

[0114] As the isocyanate compound, preferably, an isocyanurate derivative of 1,5-PDI is used.

[0115] From the viewpoint of electrolyte resistance, the crosslinking agent is preferably an epoxy compound, and more preferably an epoxy compound.

[0116] The content of the crosslinking agent is, for example, 0.1 to 5.0 parts by mass, preferably 0.7 to 3.0 parts by mass, more preferably 0.9 to 2.0 parts by mass, even more preferably 1.0 to 1.5 parts by mass, and particularly preferably 1.1 to 1.3 parts by mass, relative to 100 parts by mass of the total amount of the crystalline modified olefin polymer and the unmodified hydrogenated styrene-based elastomer.

[0117] The content of the crosslinking agent relative to 100 parts by mass of the main agent is, for example, 0.1 parts by mass to 5.0 parts by mass, preferably 0.7 parts by mass to 3.0 parts by mass, more preferably 0.9 parts by mass to 2.0 parts by mass, even more preferably 1.0 parts by mass to 1.5 parts by mass, and particularly preferably 1.1 parts by mass to 1.3 parts by mass.

[0118] The content of the crosslinking agent relative to the adhesive composition is, for example, 0.1 mass % to 5.0 mass %, preferably 0.7 mass % to 3.0 mass %, more preferably 0.9 mass % to 2.0 mass %, even more preferably 1.0 mass % to 1.5 mass %, and particularly preferably 1.1 mass % to 1.3 mass %.

[0119] The crosslinking agents can be used alone or in combination of two or more.

[0120] <Catalyst> The adhesive composition preferably contains a catalyst from the viewpoint of promoting the crosslinking reaction of the crosslinking agent.

[0121] Examples of the catalyst include amine compounds and phosphine compounds.

[0122] Examples of the amine compound include strongly basic tertiary amines. Examples of the strongly basic tertiary amine include 1,8-diazabicyclo[5.4.0]undecene-7-ene (DBU) and 1,6-diazabicyclo[3.4.0]-5-nonene (DBN). From the viewpoints of adhesive strength and electrolyte resistance, DBU is preferably used as the amine compound.

[0123] An example of the phosphine compound is triphenylphosphine.

[0124] From the viewpoint of heat resistance, the catalyst preferably contains an amine compound or a phosphine compound. From the viewpoint of electrolyte resistance, the catalyst does not contain a phosphine compound and is composed of an amine compound.

[0125] The catalyst content is, for example, 0.01 to 5.0 parts by mass, preferably 0.05 to 1.0 part by mass, and more preferably 0.1 to 0.5 parts by mass, relative to 100 parts by mass of the total amount of the crystalline modified olefin polymer and the unmodified hydrogenated styrene-based elastomer.

[0126] The catalyst content is, for example, 0.01 to 5.0 parts by mass, preferably 0.05 to 1.0 part by mass, and more preferably 0.1 to 0.5 parts by mass, relative to 100 parts by mass of the base agent.

[0127] The catalyst content relative to the adhesive composition is, for example, 0.01 to 5.0 mass %, preferably 0.05 to 1.0 mass %, and more preferably 0.1 to 0.5 mass %.

[0128] The catalysts can be used alone or in combination of two or more kinds.

[0129] <Preparation of Adhesive Composition> To prepare the adhesive composition, the base agent, the curing agent (crosslinking agent), and the catalyst that is added as needed are mixed together.

[0130] In the above mixing, additives may be blended into the adhesive composition in an appropriate ratio, such as leveling agents, antifoaming agents, antioxidants, heat stabilizers, ultraviolet absorbers, plasticizers, surfactants, pigments, thixotropic agents, thickeners, tackifiers, surface conditioners, antisettling agents, weathering agents, pigment dispersants, antistatic agents, fillers, antifungal agents, and silane coupling agents.

[0131] This prepares an adhesive composition.

[0132] The adhesive composition may also be diluted with a known organic solvent (for example, a mixed solvent of methylcyclohexane and ethyl acetate) during and / or after the preparation.

[0133] When the adhesive composition is diluted, the solid content concentration is, for example, 10% by mass to 70% by mass.

[0134] <Effects> The adhesive composition contains an unmodified hydrogenated styrene-based elastomer having a weight average molecular weight of 10,000 or more and 80,000 or less, which can improve the electrolyte resistance.

[0135] The adhesive composition has excellent electrolyte resistance and can therefore be suitably used, for example, as an adhesive for packaging materials for battery cases.

[0136] In the following description, a laminate having an adhesive layer made of a dried product of the adhesive composition, a packaging material having the laminate, and a packaging material for a battery case having the packaging material will be described in detail.

[0137] <Laminate> One embodiment of the laminate of the present invention will be described with reference to FIG.

[0138] In Figure 1, the up-down direction of the paper surface is the up-down direction (thickness direction), and the upper side of the paper surface is the upper side (one side in the thickness direction), and the lower side of the paper surface is the lower side (the other side in the thickness direction). The left-right direction and the depth direction of the paper surface are surface directions perpendicular to the up-down direction. Specifically, they correspond to the directional arrows in each figure.

[0139] The laminate 10 has a film shape (including a sheet shape) with a predetermined thickness. The laminate 10 extends in a plane direction perpendicular to the thickness direction. The laminate 10 has a flat upper surface and a flat lower surface.

[0140] The laminate 10 includes a first adhesive layer 1 and a substrate 2 in this order toward one side in the thickness direction. Specifically, the laminate 10 includes the first adhesive layer 1 and the substrate 2 that is placed directly on the upper surface (one side in the thickness direction) of the first adhesive layer 1.

[0141] There is no particular limitation on the thickness of the laminate 10. The thickness of the laminate 10 is, for example, 10 μm to 150 μm.

[0142] [First Adhesive Layer] The first adhesive layer 1 is an adhesive layer for bonding any adherend to a substrate 2. The first adhesive layer 1 is made of a dried adhesive composition.

[0143] Next, to arrange (form) the first adhesive layer 1, an adhesive composition (varnish of the adhesive composition) is applied to the other surface in the thickness direction of the substrate 2, and if necessary, heated and dried, as described in detail below. In this way, the first adhesive layer 1 is arranged (formed).

[0144] The thickness of the first adhesive layer 1 is, for example, 1 μm to 50 μm.

[0145] [Substrate 2] The substrate 2 has a film shape (including a sheet shape) with a predetermined thickness.

[0146] The material of the substrate 2 is not particularly limited. Examples of the material of the substrate 2 include polymeric materials and metal materials. Examples of the polymeric materials include olefin resins (e.g., polyethylene and polypropylene), acrylic resins, polyester resins, polycarbonate resins, acrylonitrile-styrene-butadiene copolymer resins (ABS resins), polyamide resins (e.g., nylon), and polyphenylene sulfide resins. Examples of the metal materials include aluminum, gold, silver, copper, nickel, zinc, titanium, cobalt, indium, and chromium.

[0147] There is no particular limitation on the thickness of the substrate 2. The thickness of the substrate 2 is, for example, 10 μm to 100 μm.

[0148] [Manufacturing of Laminate] One embodiment of a method for manufacturing a laminate will be described with reference to FIGS. 2A and 2B.

[0149] The manufacturing method of the laminate 10 includes a first step of preparing a substrate 2, and a second step of applying an adhesive composition (varnish of the adhesive composition) to the other thickness-wise surface of the substrate 2 and arranging (forming) a first adhesive layer 1 on the other thickness-wise surface of the substrate 2.

[0150] In the first step, a substrate 2 is prepared as shown in FIG. 2A.

[0151] In the second step, as shown in FIG. 2B, the first adhesive layer 1 is disposed (formed) on the other surface in the thickness direction of the substrate 2.

[0152] To dispose (form) the first adhesive layer 1 on the other surface in the thickness direction of the substrate 2, an adhesive composition (varnish of the adhesive composition) is applied to the other surface in the thickness direction of the substrate 2.

[0153] In order to apply the adhesive composition (varnish of the adhesive composition) to the other surface in the thickness direction of the substrate 2, first, the other surface in the thickness direction of the substrate 2 is subjected to a surface treatment, if necessary.

[0154] Examples of the surface treatment include corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, and saponification treatment, and preferably corona treatment.

[0155] Next, the adhesive composition (varnish of the adhesive composition) is applied to the other surface in the thickness direction of the substrate 2 by a known method, and is dried by heating if necessary.

[0156] The heating temperature is, for example, 50° C. to 150° C., preferably 90° C. to 130° C. The heating time is, for example, 10 seconds to 120 seconds.

[0157] As a result, the first adhesive layer 1, which is a dried product of the adhesive composition, is disposed (formed) on the other surface in the thickness direction of the substrate 2. In this way, the laminate 10 is produced.

[0158] Such a laminate 10 includes a first adhesive layer 1 made of a dried adhesive composition. Therefore, when this laminate 10 is bonded to any adherend via the first adhesive layer 1, the electrolyte resistance can be improved.

[0159] <Packaging Material> One embodiment of the packaging material of the present invention will be described with reference to FIG.

[0160] The packaging material 20 has a film shape (including a sheet shape) with a predetermined thickness. The packaging material 20 extends in a plane direction perpendicular to the thickness direction. The packaging material 20 has a flat upper surface and a flat lower surface.

[0161] The packaging material 20 includes an inner layer 3 and a laminate 10 (the laminate 10 including a first adhesive layer 1 and a base material 2 in that order toward one side in the thickness direction) in that order toward one side in the thickness direction. Specifically, the packaging material 20 includes the inner layer 3 and the laminate 10 disposed directly on the upper surface (one side in the thickness direction) of the inner layer 3.

[0162] There are no particular limitations on the thickness of the packaging material 20. The thickness of the packaging material 20 is, for example, 15 μm to 300 μm.

[0163] [Inner Layer] The inner layer 3 is a layer that becomes the inside when the packaging material 20 is made into a bag shape.

[0164] The material of the inner layer 3 is appropriately selected depending on whether the packaging material 20 has heat sealing properties and the type of contents to be contained in the bag when the packaging material 20 is formed into a bag. As will be described in detail later, when the contents to be contained are an electrolyte solution, a polyolefin film is selected.

[0165] There is no particular limitation on the thickness of the inner layer 3. The thickness of the inner layer 3 is, for example, 30 μm to 600 μm.

[0166] [Manufacturing of Packaging Material] To manufacture the packaging material 20, the inner layer 3 is placed on the other thickness-wise surface of the laminate 10 (the other thickness-wise surface of the first adhesive layer 1), and the first adhesive layer 1 is aged. This hardens the first adhesive layer 1, bonding the inner layer 3 and the laminate 10 together. In this manner, the packaging material 20 is manufactured.

[0167] The aging temperature is, for example, 20° C. to 90° C., or preferably 40° C. to 80° C. The aging time is, for example, 1 to 7 days, or preferably 2 to 5 days.

[0168] The packaging material 20 includes the laminate 10. Therefore, the resistance to the electrolyte can be improved.

[0169] <Battery Case Packaging Material and Battery> With reference to FIG. 4, one embodiment of the battery case packaging material of the present invention and a battery using this battery case packaging material will be described.

[0170] The battery 30 includes a battery case packaging material 31 and an electrolyte 32 packaged in the battery case packaging material 31. The battery 30 also includes a positive electrode 33, a negative electrode 34, and a separator 35 housed in the battery case packaging material 31.

[0171] [Battery Case Packaging Material] The battery case packaging material 31 is configured in a bag shape so that the inner layer 3 of the battery case packaging material 31 comes into contact with the electrolyte solution 32. Specifically, the battery case packaging material 31 packages the electrolyte solution 32 so that the inner layer 3 comes into contact with the electrolyte solution 32.

[0172] 4A, the battery case packaging material 31 includes a packaging material 20 (the packaging material 20 including an inner layer 3, a first adhesive layer 1, and a substrate 2, in that order toward one side in the thickness direction), a second adhesive layer 4, and an outer layer 5, in that order toward one side in the thickness direction. Specifically, the battery case packaging material 31 includes the packaging material 20, the second adhesive layer 4 disposed directly on the upper surface (one side in the thickness direction) of the packaging material 20, and the outer layer 5 disposed directly on the upper surface (one side in the thickness direction) of the second adhesive layer 4.

[0173] As described above, the packaging material 20 includes the inner layer 3, the first adhesive layer 1, and the substrate 2, arranged in this order toward one side in the thickness direction. In the battery case packaging material 31, a polyolefin film is selected for the inner layer 3 from the viewpoint of chemical resistance (electrolyte resistance) to the electrolyte 32. Examples of polyolefin films include polyethylene-based films and polypropylene-based films. Examples of polyethylene-based films include low-density polyethylene films (LDPE) and linear low-density polyethylene films (LLDPE). Examples of polypropylene-based films include oriented polypropylene films (CPP films), uniaxially oriented polypropylene films, and biaxially oriented polypropylene films (OPP films). The polyolefin film is preferably a polypropylene-based film, more preferably an oriented polypropylene film (CPP film).

[0174] In the battery case packaging material 31, the material of the substrate 2 is preferably a metal material, more preferably aluminum.

[0175] The second adhesive layer 4 is formed from a known adhesive. Alternatively, the above adhesive composition may be used instead of the known adhesive.

[0176] There are no particular limitations on the thickness of the second adhesive layer 4. The thickness of the second adhesive layer 4 is, for example, 1 μm to 50 μm.

[0177] The outer layer 5 is a layer that forms the outside of the battery case packaging material 31 .

[0178] Examples of materials for the outer layer 5 include the polymer materials exemplified for the substrate 2 described above, preferably polyamide resin, and more preferably nylon.

[0179] There is no particular limitation on the thickness of the outer layer 5. The thickness of the outer layer 5 is, for example, 10 μm to 100 μm.

[0180] The battery case packaging material 31 is manufactured by placing an outer layer 5 on one thickness-wise surface of the packaging material 20 (one thickness-wise surface of the substrate 2) via a second adhesive layer 4 formed by applying a known adhesive (or adhesive composition).

[0181] The battery case packaging material 31 includes the packaging material 20. Therefore, the resistance to the electrolyte can be improved.

[0182] In FIG. 4, both ends of the battery case packaging material 31 (opposing inner layers 3) are sealed by heat sealing to form a bag.

[0183] [Electrolyte Solution] The electrolyte solution 32 is not particularly limited, and may contain, for example, ethylene carbonate, diethyl carbonate, dimethyl carbonate, and a lithium salt such as lithium hexafluorophosphate.

[0184] The positive electrode 33 and the negative electrode 34 are disposed facing each other with a gap therebetween and in contact with the electrolyte solution 32. The separator 35 is disposed so as to be sandwiched between the positive electrode 33 and the negative electrode 34.

[0185] The battery 30 is used as, for example, a lithium ion secondary battery. In such a case, the battery case packaging material 31 is used as a lithium ion secondary battery case packaging material.

[0186] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be substituted with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention."

[0187] <Details of Components> The trade names and abbreviations of the components used in each Production Example, each Example, and each Comparative Example are described in detail below. Kraton G1726VS: hydrogenated styrene-ethylene-butene-styrene copolymer, weight average molecular weight 50,000, manufactured by Kraton Corporation Septon 2002NT: hydrogenated styrene-ethylene-propylene-styrene copolymer, weight average molecular weight 55,000, manufactured by Kuraray Co., Ltd. Kraton G1730VO: hydrogenated styrene-ethylene-propylene-styrene copolymer, weight average molecular weight 93,000, manufactured by Kraton Corporation Kraton D1162PT: unsaturated styrene-isoprene-styrene copolymer, weight average molecular weight 86,000, manufactured by Kraton Corporation Kraton D1117PT: unsaturated styrene-isoprene-styrene copolymer, weight average molecular weight 130,000, manufactured by Kraton Corporation Kraton D1171PT: unsaturated styrene-isoprene-butadiene-styrene copolymer, weight average molecular weight 145,000, manufactured by Kraton Corporation Kraton G1652MU, hydrogenated styrene-ethylene-butene-styrene copolymer, manufactured by Kraton Corporation; jER152: phenol novolac resin, manufactured by Mitsubishi Chemical Corporation; RPS-1005: oxazoline group-containing polystyrene, trade name "Epocross RPS-1005", manufactured by Nippon Shokubai Co., Ltd.; Epocross Co., Ltd.; Stabio D370N: isocyanurate of 1,5-pentamethylene diisocyanate; DBU: 1,8-diazabicyclo[5.4.0]undecene-7, manufactured by Wako Co., Ltd.; DBN: 1,6-diazabicyclo[3.4.0]-5-nonene, manufactured by Tokyo Chemical Industry Co., Ltd.; TPP: triphenylphosphine, manufactured by Wako Co., Ltd.

[0188] <Production of Crystalline α-Olefin Polymer Having 2 to 20 Carbon Atoms> Production Example 1-1 (Production of Propylene / 1-Butene Copolymer) A 2-liter autoclave purged with nitrogen was charged with 900 ml of hexane and 90 g of 1-butene, and 1 mmol of triisobutylaluminum was added, followed by heating to 70° C. Thereafter, propylene was supplied to the autoclave under a total pressure of 7 kg / cm. ２G, 0.30 mmol of methylaluminoxane and 0.001 mmol of rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride (calculated as Zr atom) were added, and propylene was continuously supplied to maintain the total pressure at 7 kg / cm ２ Polymerization was carried out for 30 minutes while maintaining the temperature at 50°C. After polymerization, the polymer was degassed and recovered in a large amount of methanol, and then dried under reduced pressure at 110°C for 12 hours. This yielded a crystalline α-olefin polymer having 2 to 20 carbon atoms (propylene / 1-butene copolymer). The crystalline α-olefin polymer having 2 to 20 carbon atoms had a melting point of 78.3°C, a heat of fusion of 29.2 J / g, a weight-average molecular weight of 330,000, and a propylene content of 67.2 mol%.

[0189] Production Example 1-2 (Production of Propylene / 1-Butene Copolymer) A 2-liter autoclave purged with nitrogen was charged with 900 ml of hexane and 80 g of 1-butene, and 1 mmol of triisobutylaluminum was added thereto, followed by heating to 70° C. Thereafter, propylene was supplied to the autoclave under a total pressure of 7 kg / cm. ２ G, 0.30 mmol of methylaluminoxane and 0.001 mmol of rac-dimethylsilylene-bis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride (calculated as Zr atom) were added, and propylene was continuously supplied to maintain the total pressure at 7 kg / cm ２ Polymerization was carried out for 30 minutes while maintaining the temperature at 50°C. After polymerization, the polymer was degassed and recovered in a large amount of methanol, and then dried under reduced pressure at 110°C for 12 hours. This yielded a crystalline α-olefin polymer having 2 to 20 carbon atoms (propylene / 1-butene copolymer). The crystalline α-olefin polymer having 2 to 20 carbon atoms had a melting point of 86°C, a heat of fusion of 36 J / g, a weight-average molecular weight of 330,000, and a propylene content of 73.5 mol%.

[0190] <Production of Crystalline Modified Olefin Polymer> Production Example 2-1 (Production of Maleic Anhydride-Modified Propylene / 1-Butene Copolymer) 3 kg of the crystalline C2-20 α-olefin polymer (propylene / 1-butene copolymer) of Production Example 1-1 was added to 10 L of toluene, and the temperature was raised to 145°C under a nitrogen atmosphere to dissolve in toluene. Furthermore, 764 g of maleic anhydride and 350 g of di-tert-butyl peroxide were added over 4 hours with stirring, and then the mixture was stirred at 145°C for 2 hours. After cooling, a large amount of acetone was added, followed by filtration, washing with acetone, and vacuum drying. This gave a crystalline modified olefin polymer (maleic anhydride-modified propylene / 1-butene copolymer). Furthermore, the crystalline modified olefin polymer had a melting point of 75.5°C, a heat of fusion of 26.0 J / g, and a weight average molecular weight of 120,000, and the amount of maleic anhydride modification in the crystalline α-olefin polymer having 2 to 20 carbon atoms was 1.4% by mass.

[0191] Production Examples 2-2 to 2-6 (Production of Maleic Anhydride-Modified Propylene / 1-Butene Copolymers) Crystalline modified olefin polymers (maleic anhydride-modified propylene / 1-butene copolymers) were produced according to the same procedure as in Production Example 2-1, except that the blending ratio of maleic anhydride and the blending ratio of di-tert-butyl peroxide were changed based on the description in Table 1.

[0192] <Preparation of Acid-Modified Styrenic Elastomer> Preparation Example 3: 3 kg of Kraton G1652MU (hydrogenated styrene-ethylene-butene-styrene copolymer) was added to 10 L of toluene and heated to 145°C under a nitrogen atmosphere to dissolve in toluene. Furthermore, 840 g of maleic anhydride and 175 g of di-tert-butyl peroxide were added over 4 hours with stirring, followed by stirring at 145°C for 2 hours. After cooling, a large amount of acetone was added, followed by filtration, washing with acetone, and vacuum drying. This yielded an acid-modified styrene-based elastomer. The acid-modified styrene-based elastomer had no observed melting point or heat of fusion, a weight-average molecular weight of 100,000, and the amount of maleic anhydride modification in the hydrogenated styrene-ethylene-butene-styrene copolymer was 2.0% by mass.

[0193] <Production of Adhesive Compositions> Examples 1 to 12 and Comparative Examples 1 to 9 According to the formulations shown in Tables 2 to 5, a crystalline modified olefin polymer, an unmodified hydrogenated styrene-based elastomer, and other styrene-based elastomers were mixed in a nitrogen-purged 1-liter flask equipped with a stirring blade, and then 400 g of a solvent (a mixed solvent of methylcyclohexane / ethyl acetate=240 / 160) was added, followed by stirring at 60° C. for 3 hours to dissolve the components. This prepared the main components.

[0194] Next, a crosslinking agent (curing agent) and a catalyst were added to the base resin, and the mixture was further diluted with the mixed solvent to produce an adhesive composition (solid content concentration: 12.5% ​​by mass).

[0195] <Evaluation> [Content of structural units derived from propylene] The content of structural units derived from propylene in the crystalline α-olefin polymers having 2 to 20 carbon atoms in each production example was evaluated as follows: １３ Measurement was performed by C-NMR.

[0196] [Heat of Fusion] The heat of fusion of the crystalline α-olefin polymer having 2 to 20 carbon atoms and the crystalline modified olefin polymer of each Production Example was measured in accordance with JIS K7122.

[0197] [Weight-average molecular weight] The weight-average molecular weight was measured for the crystalline α-olefin polymer having 2 to 20 carbon atoms, the crystalline modified olefin polymer, the unmodified hydrogenated styrene-based elastomer, and other styrene-based elastomers of each Production Example. Specifically, GPC measurement was carried out under the following conditions, and the weight-average molecular weight was determined from a calibration curve using a commercially available monodisperse standard polystyrene. {Conditions} Apparatus: GPC-101 (manufactured by Showa Denko Co., Ltd.) Mobile phase: tetrahydrofuran Column: KF-806L x 3 + KF-803L x 3 (manufactured by Shodex Co., Ltd.) Flow rate: 1 ml / min Sample concentration: 3,000 ppm Column temperature: 40°C Injection volume: 300 μl Detector: differential refractometer Sampling time interval: 0.1 second

[0198] [Amount of modification with maleic anhydride] For the crystalline modified olefin polymers of each Production Example and the acid-modified styrene-based elastomer of Production Example 3, １ The amount of modification by maleic anhydride was measured by H-NMR, and the results are shown in Table 1.

[0199] [Acid Value of Base Component] 35 ml of toluene and 15 ml of n-butanol were added to an Erlenmeyer flask, and 0.8 g of a diluted solution prepared by diluting 0.1 g of special-grade bromothymol blue with 100 ml of 19% ethanol was added to prepare a solution. Next, N / KOH-ethanol solution was added to this solution until the solution turned green, and then 5 g of the base component from each Example and Comparative Example was added and completely dissolved. This solution was then titrated with N / KOH-ethanol solution until the solution turned blue, the titration amount was measured, and the acid value was calculated based on the following formula (1). The results are shown in Tables 2 to 5. Acid value (mg KOH / g) = (sample titration amount × factor × 5.61) / sample weight (1)

[0200] [Stability of base agent] The base agents in each Example and Comparative Example were stored at 22°C for 7 days. The stability of the base agents was evaluated based on the following criteria. The results are shown in Tables 2 to 5. {Criteria} ◯: The base agent was a homogeneous liquid. ×: Separation and / or precipitation was observed in the base agent.

[0201] [Adhesive Strength] (Production of Packaging Material) The adhesive composition of each Example and Comparative Example was applied to the other surface of aluminum foil in the thickness direction using a bar coater, and dried at 120°C for 30 seconds (dry film thickness: approximately 3.0 to 3.5 µm), thereby disposing (forming) a first adhesive layer on the other surface of the aluminum foil in the thickness direction.

[0202] Next, an 80 μm thick CPP film (one side corona treated) was placed on the other side of the first adhesive layer in the thickness direction (the other side of the first adhesive layer in the thickness direction and the corona treated side of the CPP film were bonded together). After that, it was aged at 80° C. for 3 days. In this way, a packaging material was manufactured. In Examples 3 to 5, it was aged at 60° C. for 3 days.

[0203] (Measurement of adhesive strength (22°C)) The obtained packaging material was cut into a width of 15 mm to prepare a test piece, and a 180° peel test was performed on this test piece using a universal tensile tester at 22°C and a crosshead speed of 50 mm / min to measure the peel strength of the aluminum foil / CPP. The results are shown in Tables 2 to 5.

[0204] [Heat Resistance] (Measurement of Adhesion Strength (80°C)) The obtained packaging material was cut into a width of 15 mm to prepare a test piece, and a 180° peel test was performed on this test piece using a universal tensile tester at 80°C and a crosshead speed of 50 mm / min to measure the peel strength of the aluminum foil / CPP. The results are shown in Tables 2 to 5.

[0205] (Measurement of adhesive strength (120°C)) The obtained packaging material was cut into a width of 15 mm to prepare a test piece, and a 180° peel test was performed on this test piece using a universal tensile tester at 120°C and a crosshead speed of 50 mm / min to measure the peel strength of the aluminum foil / CPP. The results are shown in Tables 2 to 5.

[0206] [Electrolyte Resistance] The obtained packaging material was cut into a size of 15 mm in width to prepare a test piece. ６ The aluminum foil was immersed in an electrolyte (a 3:7 volume% mixture of ethylene carbonate and diethyl carbonate with 1000 ppm water added) at 85°C for 7 days. Then, a 180° peel test was performed at 22°C and a crosshead speed of 50 mm / min using a universal tensile tester to measure the aluminum foil / CPP peel strength. The results are shown in Tables 2 to 5.

[0207]

[0208]

[0209]

[0210]

[0211]

[0212] The above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and should not be interpreted as limiting. Modifications of the present invention that are obvious to those skilled in the art are intended to be included in the scope of the following claims.

[0213] The adhesive composition, laminate, packaging material, and battery case packaging material of the present invention are suitably used, for example, in the production of lithium batteries.

[0214] 1 First adhesive layer 2 Base material 3 Inner layer 4 Second adhesive layer 5 Outer layer 10 Laminated body 20 Packaging material 31 Packaging material for battery case

Claims

1. An adhesive composition comprising: a base material containing a crystalline modified olefin polymer and an unmodified hydrogenated styrene-based elastomer; and a curing agent containing a crosslinking agent; wherein the crystalline modified olefin polymer is a crystalline α-olefin polymer having 2 to 20 carbon atoms modified with a monomer having a functional group reactive with an epoxy group, an oxazoline group, or an isocyanate group; and wherein the weight average molecular weight of the unmodified hydrogenated styrene-based elastomer is 10,000 or more and 80,000 or less.

2. The adhesive composition according to claim 1, wherein the acid value of the base agent is 10 mgKOH / g or more and 30 mgKOH / g or less.

3. The adhesive composition according to claim 1, wherein the crystalline α-olefin polymer having 2 to 20 carbon atoms contains structural units derived from propylene.

4. The adhesive composition according to claim 3, wherein the content of the propylene-derived structural units is 40 mol % or more and 95 mol % or less relative to the crystalline α-olefin polymer having 2 to 20 carbon atoms.

5. The adhesive composition according to claim 4, wherein the crystalline polymer of an α-olefin having 2 to 20 carbon atoms comprises structural units derived from propylene and structural units derived from an α-olefin having 4 to 20 carbon atoms.

6. The adhesive composition according to claim 1, wherein the functional group is a carboxyl group or an acid anhydride group.

7. The adhesive composition according to claim 1, wherein the crosslinking agent is at least one selected from the group consisting of epoxy compounds, oxazoline compounds, and isocyanate compounds.

8. The adhesive composition according to claim 1, further comprising a catalyst, wherein the catalyst comprises an amine compound or a phosphine compound.

9. The adhesive composition according to claim 1, wherein the content of the crystalline modified olefin polymer is 70 parts by mass or more and 95 parts by mass or less, relative to 100 parts by mass of the total amount of the crystalline modified olefin polymer and the unmodified hydrogenated styrene-based elastomer, and the content of the unmodified hydrogenated styrene-based elastomer is 5 parts by mass or more and 30 parts by mass or less, relative to 100 parts by mass of the total amount of the crystalline modified olefin polymer and the unmodified hydrogenated styrene-based elastomer.

10. A laminate comprising, in order toward one side in the thickness direction, a first adhesive layer made of a dried product of the adhesive composition according to any one of claims 1 to 9 and a substrate.

11. A packaging material comprising an inner layer and the laminate according to claim 10 in this order towards one side in the thickness direction.

12. A packaging material for a battery case, comprising the packaging material according to claim 11, a second adhesive layer, and an outer layer, arranged in this order toward one side in the thickness direction.

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