Polyolefin adhesive composition, laminate, and packaging material for lithium ion battery

Abstract

The present invention provides an adhesive composition having good pot life, adhesiveness, heat resistance, chemical resistance to an electrolyte and moldability. The present invention specifically provides an adhesive composition comprising an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organic aluminum compound (C), wherein the acid-modified polyolefin (A) has a weight average molecular weight (Mw) in the range of 10,000-200,000.

Description

Polyolefin adhesive composition, laminate, and packaging material for lithium-ion batteries

[0001] The present invention relates to a polyolefin-based adhesive composition, a laminate, and a packaging material for lithium-ion batteries.

[0002] In recent years, lithium ion batteries (hereinafter also referred to as "LiBs") that can be made ultra-thin and compact have been actively developed as batteries for use in personal computers, portable terminal devices such as mobile phones, video cameras, satellites, etc. Unlike the conventionally widely known metal cans, the packaging materials for these LiBs have come to use laminates with a multilayer structure such as a substrate layer / barrier layer / sealant layer, because of their advantages of being lightweight and allowing for flexible selection of the battery shape.

[0003] LiBs contain, as their battery contents, cathode and anode materials, as well as an electrolyte solution containing a lithium salt dissolved in an aprotic solvent such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate, or an electrolyte layer composed of a polymer gel impregnated with the electrolyte. It is known that when such a highly permeable electrolyte solution passes through the sealant layer, it reduces the laminate strength between the barrier layer and the sealant layer, causing delamination and ultimately electrolyte leakage. Furthermore, while substances such as LiPF6 and LiBF4 are used as lithium salts for battery electrolytes, these salts generate hydrofluoric acid upon hydrolysis with water, which corrodes the barrier layer and reduces laminate strength. LiB adhesives must be durable against the electrolyte solution and electrolyte. LiB adhesives must also exhibit adhesive performance when bonded together at temperatures below 120°C.

[0004] Furthermore, LiBs must be durable, assuming they will be used in a variety of environments. For example, when LiBs are used in mobile devices, they must be leak-resistant in environments of around 80°C. In-vehicle LiBs are expected to be used in higher-temperature environments than typical small LiBs, so LiB adhesives must be heat-resistant to around 80°C.

[0005] Under these circumstances, adhesives for lithium ion batteries have been proposed that aim to improve heat resistance and chemical resistance to the electrolyte, and an adhesive composition using an acid-modified polyolefin and an isocyanate curing agent has been disclosed (for example, Patent Document 1).

[0006] Furthermore, in order to improve chemical resistance to the electrolyte solution over a long period of time, a battery packaging material containing an acid-modified polyolefin, a polyfunctional isocyanate curing agent, and an organometallic catalyst such as tin, titanium, or zirconium has been proposed (for example, Patent Document 2).

[0007] International Publication No. 2021 / 106849 Japanese Patent Application Laid-Open No. 2018-49849

[0008] However, in Patent Document 1, a long curing time of 5 days at 40° C. is required to sufficiently promote the curing reaction.

[0009] In the lithium battery casing material containing an organometallic catalyst described in Patent Document 2, the organotin compound accelerates the curing reaction by its catalytic function, but prolonged stirring causes significant thickening and gelation, so the pot life is not fully satisfied. Furthermore, the lithium battery casing material described in Patent Document 2 is poor in heat resistance and chemical resistance to the electrolyte.

[0010] Furthermore, in recent years, the toxicity of organotin compounds has been pointed out, and tributyltin (TBT) contained in dibutyltin compounds in particular is also a concern as an endocrine disruptor, so there are restrictions on their use. Furthermore, with regard to organotitanium compounds and organozirconium compounds, the effect of accelerating the hardening reaction was insufficient when the curing time was short.

[0011] The present invention has been made in view of the above, and an object of the present invention is to provide an adhesive composition that is excellent in pot life, adhesion, heat resistance, chemical resistance to an electrolytic solution, and moldability.

[0012] As a result of extensive research into achieving the above object, the present inventors have found that the above object can be achieved by containing an acid-modified polyolefin having a weight-average molecular weight within a specific range, a polyfunctional polyisocyanate curing agent, and an organoaluminum compound, and have thus completed the present invention.

[0013] The present invention encompasses, for example, the subject matter described in the following items: Item 1. An adhesive composition comprising an acid-modified polyolefin (A), a multifunctional polyisocyanate curing agent (B), and an organoaluminum compound (C), wherein the weight average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000.

[0014] The adhesive composition of the present invention is excellent in pot life, adhesion, heat resistance, chemical resistance to the electrolyte, and moldability. Because the adhesive composition of the present invention has these properties, it can be suitably used as a packaging material for lithium-ion batteries.

[0015] Preferred embodiments of the present invention will be described in detail below. The following description of the components may be based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

[0016] In this specification, the expressions "contain" and "comprise" include the concepts of "contain," "include," "consist essentially of," and "consist only of."

[0017] In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example. Furthermore, in this specification, a numerical value connected with "to" means a numerical range that includes the numbers before and after "to" as the upper and lower limits.

[0018] In this specification, "A and / or B" means "one of A and B" or "both A and B," and specifically means "A," "B," or "A and B."

[0019] As used herein, "n-" means "normal," "iso-" means "iso," "sec-" means "secondary," and "tert-" or "t-" means "tertiary."

[0020] In this specification, room temperature means a temperature within the range of 20°C to 25°C.

[0021] 1. Adhesive Composition The adhesive composition of this embodiment has the following components (I) and (II): (I) Contains an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organoaluminum compound (C). (II) The weight-average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000.

[0022] The adhesive composition of the present embodiment has the above-described configurations (I) and (II), and therefore has good pot life, adhesion, heat resistance, chemical resistance to the electrolyte, and moldability.

[0023] <Acid-Modified Polyolefin (A)> The present invention contains an acid-modified polyolefin (A) as an essential component. In one embodiment, the acid-modified polyolefin (A) is preferably a polymer obtained by grafting at least one of an α,β-unsaturated carboxylic acid and an acid anhydride thereof onto a polyolefin. In other words, in one embodiment, the acid-modified polyolefin (A) is preferably a graft polymer having a structure in which at least one of an α,β-unsaturated carboxylic acid and an acid anhydride thereof is grafted onto a polyolefin.

[0024] Examples of polyolefins include homopolyethylene (a homopolymer of ethylene), homopolypropylene (a homopolymer of propylene), and propylene-α-olefin copolymers. These polyolefins can be used alone or in combination of two or more. In one embodiment, among these polyolefins, homopolypropylene and / or propylene-α-olefin copolymers are preferred.

[0025] In one embodiment, the acid-modified polyolefin (A) is more preferably a graft polymer having a structure in which an α,β-unsaturated carboxylic acid or an acid anhydride thereof is grafted onto a homopolypropylene or a propylene-α-olefin copolymer.

[0026] Propylene-α-olefin copolymers are copolymers of propylene as a main component with an α-olefin. Examples of α-olefins include ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, and vinyl acetate. These α-olefins can be used alone or in combination of two or more. In one embodiment, the α-olefin in the propylene-α-olefin copolymer is preferably ethylene and / or 1-butene, and more preferably 1-butene.

[0027] In one embodiment, the content of the propylene component in the propylene-α-olefin copolymer is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more. When the content of the propylene component in the propylene-α-olefin copolymer is 50 mol% or more, the adhesive strength of the adhesive composition to polyolefin substrates (particularly polypropylene substrates) becomes even better.

[0028] Examples of the α,β-unsaturated carboxylic acid and / or its acid anhydride to be graft polymerized onto the polyolefin include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, mesaconic acid, citraconic acid, citraconic anhydride, aconitic acid, aconitic anhydride, etc. Among these, acid anhydrides of α,β-unsaturated carboxylic acids are preferred, and maleic anhydride is more preferred.

[0029] Specific examples of the acid-modified polyolefin (A) include maleic anhydride-modified homopolypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-1-butene copolymer, maleic anhydride-modified propylene-ethylene-1-butene copolymer, etc., and these acid-modified polyolefins can be used alone or in combination of two or more. In one embodiment, the acid-modified polyolefin (A) is preferably maleic anhydride-modified homopolypropylene and / or maleic anhydride-modified propylene-1-butene copolymer, and more preferably maleic anhydride-modified homopolypropylene or maleic anhydride-modified propylene-1-butene copolymer.

[0030] A wide variety of known methods can be used to graft polymerize an α,β-unsaturated carboxylic acid or anhydride onto a polyolefin, including, for example, a melting method in which a polyolefin is heated to a temperature equal to or higher than its melting point in the presence of a radical generator to react with the α,β-unsaturated carboxylic acid or anhydride, and a solution method in which a polyolefin is dissolved in an organic solvent and then heated and stirred in the presence of a radical generator to react with the α,β-unsaturated carboxylic acid or anhydride.

[0031] As the radical generator, an organic peroxide is preferably used. Examples of the organic peroxide include peroxides such as di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexanoate, tert-butyl peroxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, and lauroyl peroxide; and azonitriles such as azobisisobutyronitrile and azobisisopropionitrile.

[0032] The acid-modified polyolefin (A) is preferably non-chlorinated. Specifically, the chlorine content is preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, and most preferably 0% by mass. A chlorine content of 3% by mass or less can reduce the environmental load. Furthermore, even when used as a packaging material for lithium-ion batteries, no chlorine or hydrogen chloride is emitted, and battery corrosion can be suppressed.

[0033] In one embodiment, the content of the acid-modified chlorinated polyolefin in the adhesive composition is preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, still more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0% by mass.

[0034] In one embodiment, the acid value of the acid-modified polyolefin (A) is preferably 2 to 50 mgKOH / g, more preferably 3 to 45 mgKOH / g, even more preferably 5 to 40 mgKOH / g, and particularly preferably 7 to 35 mgKOH / g. When the acid value of the acid-modified polyolefin (A) is 2 to 50 mgKOH / g, the compatibility between the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) is improved, and the crosslinking density tends to be good. As a result, the adhesion, heat resistance, and chemical resistance to the electrolytic solution tend to be more excellent.

[0035] The acid value of the acid-modified polyolefin (A) can be adjusted by the amounts of the α,β-unsaturated carboxylic acid, the acid anhydride of the α,β-unsaturated carboxylic acid, and the radical generator used.

[0036] In one embodiment, the acetone extractable component ratio in the acid-modified polyolefin (A) is preferably 0.01% by mass to 2% by mass, more preferably 0.03% by mass to 1.7% by mass, even more preferably 0.05% by mass to 1.4% by mass, even more preferably 0.07% by mass to 1.2% by mass, and particularly preferably 0.1% by mass to 1.0% by mass. When the acetone extractable component ratio in the acid-modified polyolefin (A) is 0.01 to 2% by mass, the production efficiency of the adhesive composition is further improved, the adhesive composition exhibits better cohesive strength, and tends to have better adhesion, chemical resistance to electrolytes, and moldability. The acetone extractable component ratio in the acid-modified polyolefin (A) is a value measured using a Soxhlet extractor after refluxing with acetone for 2 hours. Specific measurement methods are described in the Examples below.

[0037] The ratio of acetone extractable components in the acid-modified polyolefin (A) can be adjusted by reprecipitation with methyl ethyl ketone and purifying unreacted monomers, low-molecular-weight components, etc. Examples of the low-molecular-weight components include low-molecular-weight polyolefins having a weight-average molecular weight (Mw) of 100 to 10,000.

[0038] In one embodiment, the storage modulus (E') at 25°C of the acid-modified polyolefin (A) is preferably 10 to 2500 MPa, more preferably 15 to 2000 MPa, even more preferably 20 to 1500 MPa, particularly preferably 25 to 1100 MPa, and most preferably 30 to 800 MPa, from the viewpoint of further improving adhesiveness and chemical resistance to the electrolyte. When the storage modulus (E') at 25°C of the acid-modified polyolefin (A) is 10 to 2500 MPa, the adhesiveness and substrate conformability of the adhesive composition are further improved, and the moldability of the laminate is further improved. The storage modulus (E') at 25°C of the acid-modified polyolefin (A) can be measured in accordance with the test method of JIS K7244-4 (1999). Specific measurement methods will be described in the examples below.

[0039] In one embodiment, the tensile break elongation (Eb) of the acid-modified polyolefin (A) at 25°C is preferably 50% to 1000%, more preferably 80% to 900%, even more preferably 120% to 800%, particularly preferably 160% to 700%, and most preferably 200% to 600%. When the tensile break elongation (Eb) of the acid-modified polyolefin (A) at 25°C is 50% to 1000%, the adhesive properties and substrate conformability of the adhesive composition are further improved, and the moldability of the laminate is further improved. The tensile break elongation (Eb) of the acid-modified polyolefin (A) at 25°C can be measured in accordance with the test method of JIS K7161 (2014). Specific measurement methods will be described in the examples below.

[0040] The weight average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000. The Mw of the acid-modified polyolefin (A) is preferably in the range of 20,000 to 180,000, more preferably in the range of 30,000 to 160,000, particularly preferably in the range of 40,000 to 140,000, and most preferably in the range of 50,000 to 110,000. If the Mw of the acid-modified polyolefin (A) is less than 10,000, the cohesive strength of the acid-modified polyolefin (A) is weakened, resulting in poor adhesion of the adhesive composition. If the Mw of the acid-modified polyolefin (A) is more than 200,000, the fluidity of the acid-modified polyolefin (A) is reduced, resulting in a reduced pot life of the adhesive composition and problems with operability during bonding. When the Mw of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000, the acid-modified polyolefin (A) has good cohesive strength and good fluidity, and therefore the adhesive composition has good pot life, heat resistance, and chemical resistance to the electrolyte. The weight average molecular weight (Mw) of the acid-modified polyolefin (A) can be measured by gel permeation chromatography (GPC). Specific measurement methods will be described in the examples below.

[0041] In one embodiment, the acid-modified polyolefin (A) is preferably crystalline. In this specification, crystalline refers to a polyolefin that shows a clear melting peak during heating from -100°C to 250°C at a rate of 20°C / min using a differential scanning calorimeter (DSC). When the acid-modified polyolefin (A) is crystalline, the cohesive strength of the acid-modified polyolefin (A) is further improved, thereby further improving the adhesive properties, heat resistance, and chemical resistance to electrolytes of the adhesive composition.

[0042] In one embodiment, the melting point (Tm) of the acid-modified polyolefin (A) is preferably in the range of 50°C to 120°C, more preferably in the range of 60°C to 100°C, and most preferably in the range of 70°C to 90°C. The melting point (Tm) of the acid-modified polyolefin (A) can be measured using a differential scanning calorimeter (DSC). When the melting point (Tm) of the acid-modified polyolefin (A) is in the range of 50°C to 120°C, the cohesive strength of the acid-modified polyolefin (A) is further improved, and the adhesive composition therefore has even better pot life, adhesion, heat resistance, and chemical resistance to electrolytes.

[0043] In one embodiment, the heat of fusion (ΔH) of the acid-modified polyolefin (A) is preferably in the range of 1 J / g to 60 J / g, more preferably in the range of 3 J / g to 50 J / g, and most preferably in the range of 5 J / g to 40 J / g. When the heat of fusion (ΔH) of the acid-modified polyolefin (A) is in the range of 1 J / g to 60 J / g, the cohesive force derived from the crystals of the acid-modified polyolefin (A) is further improved, and the pot life, adhesive properties, heat resistance, and chemical resistance to electrolytes of the adhesive composition are further improved.

[0044] <Polyfunctional Polyisocyanate Curing Agent (B)> The present invention contains a polyfunctional polyisocyanate curing agent (B) as an essential component. The polyfunctional polyisocyanate curing agent (B) is usually a polyisocyanate compound having two or more isocyanate groups in one molecule.

[0045] In one embodiment, the multifunctional polyisocyanate curing agent (B) is preferably a diisocyanate compound or a derivative thereof, more preferably a derivative of a diisocyanate compound, from the viewpoint of further improving the heat resistance and chemical resistance to the electrolytic solution of the adhesive composition.

[0046] Examples of the diisocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, bis(4-isocyanatocyclohexyl)methane, and hydrogenated diphenylmethane diisocyanate. The diisocyanate compounds can be used alone or in combination of two or more. Of the diisocyanate compounds, hexamethylene diisocyanate is particularly preferred.

[0047] Examples of the derivatives of the diisocyanate compounds include isocyanurate-modified diisocyanate compounds, adduct-modified diisocyanate compounds, biuret-modified diisocyanate compounds, uretdione-modified diisocyanate compounds, allophanate-modified diisocyanate compounds, and prepolymers having an isocyanate residue (low polymers (molecular weight 300 g / mol to 4,000 g / mol) obtained from diisocyanate compounds and polyol compounds). The derivatives of the diisocyanate compounds can be used either alone or in combination of two or more.

[0048] In one embodiment, from the viewpoint of further improving the heat resistance and chemical resistance to the electrolyte of the adhesive composition, the derivative of the diisocyanate compound is preferably at least one selected from the group consisting of an isocyanurate-modified product of hexamethylene diisocyanate, an adduct-modified product of hexamethylene diisocyanate, a biuret-modified product of hexamethylene diisocyanate, a uretdione-modified product of hexamethylene diisocyanate, and an allophanate-modified product of hexamethylene diisocyanate.

[0049] In one embodiment, from the viewpoint of further improving the heat resistance and chemical resistance to the electrolyte of the adhesive composition, the polyfunctional polyisocyanate curing agent (B) is preferably an isocyanurate-modified diisocyanate compound and / or a biuret-modified diisocyanate compound, more preferably at least one selected from the group consisting of an isocyanurate-modified hexamethylene diisocyanate, an adduct-modified hexamethylene diisocyanate, a biuret-modified hexamethylene diisocyanate, a uretdione-modified hexamethylene diisocyanate, and an allophanate-modified hexamethylene diisocyanate, and particularly preferably an isocyanurate-modified hexamethylene diisocyanate and / or a biuret-modified hexamethylene diisocyanate.

[0050] Furthermore, a compound obtained by reacting some of the isocyanate groups of the above isocyanate compounds with a compound reactive with the isocyanate groups may be used as a polyfunctional polyisocyanate curing agent. Examples of the compound reactive with an isocyanate group include compounds containing an amino group such as butylamine, hexylamine, octylamine, 2-ethylhexylamine, dibutylamine, ethylenediamine, benzylamine, and aniline; compounds containing a hydroxyl group such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, octanol, 2-ethylhexyl alcohol, dodecyl alcohol, ethylene glycol, propylene glycol, benzyl alcohol, and phenol; compounds containing an epoxy group such as allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and cyclohexanedimethanol diglycidyl ether; and compounds containing a carboxylic acid such as acetic acid, butanoic acid, hexanoic acid, octanoic acid, succinic acid, adipic acid, sebacic acid, and phthalic acid.

[0051] In one embodiment, the content of the polyfunctional polyisocyanate curing agent (B) is preferably 0.5 to 70 parts by mass, more preferably 1 to 65 parts by mass, even more preferably 2 to 60 parts by mass, even more preferably 3 to 55 parts by mass, even more preferably 6 to 50 parts by mass, particularly preferably 10 to 45 parts by mass, and most preferably 15 to 40 parts by mass, relative to 100 parts by mass of the acid-modified polyolefin (A). When the content of the polyfunctional polyisocyanate curing agent (B) is 0.5 to 70 parts by mass relative to 100 parts by mass of the acid-modified polyolefin (A), the adhesive composition cures better, the adhesive composition has better conformability to the substrate, and is even more excellent in adhesion, heat resistance, chemical resistance to electrolytic solutions, and moldability.

[0052] <Organoaluminum Compound> The present invention contains an organoaluminum compound (C) as an essential component. By containing the organoaluminum compound (C), the curing reaction of the adhesive composition is accelerated in a short curing period, and the adhesive composition can be cured well by the aging step after lamination. Furthermore, by containing the organoaluminum compound (C), the adhesive composition has good pot life, heat resistance, and chemical resistance to electrolytes.

[0053] In one embodiment, the organoaluminum compound (C) is preferably an aluminum alcoholate compound and / or an aluminum chelate compound, more preferably an aluminum chelate compound.

[0054] Examples of aluminum alcoholate compounds include aluminum ethylate, aluminum isopropylate, aluminum diisopropylate monosec-butylate, and aluminum sec-butylate, and these can be used either alone or in combination of two or more.

[0055] An aluminum chelate compound is usually a compound in which one or more polydentate ligands L are bound to a central aluminum atom. The aluminum chelate compound may or may not have one or more monodentate ligands X bound to the aluminum atom.

[0056] For example, when the general formula of an aluminum chelate compound containing one aluminum atom is represented by Al(L)m(X)n, m is an integer of 1 or more, and n is an integer of 0 or more. When m is 2 or more, the m Ls may be the same ligand or different ligands. When n is 2 or more, the n Xs may be the same ligand or different ligands.

[0057] Examples of the multidentate ligand L include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate, as well as keto-enol tautomer-forming compounds such as acetylacetone (2,4-pentanedione), 2,4-hexanedione, and benzoylacetone. A keto-enol tautomer-forming compound refers to a compound that can form a keto-enol tautomer. In the multidentate ligand L, these keto-enol tautomer-forming compounds may be enolates (e.g., acetylacetonate) in which the enol is deprotonated.

[0058] Examples of the monodentate ligand X include halogen atoms such as chlorine and bromine atoms, acyloxy groups such as pentanoyl, hexanoyl, 2-ethylhexanoyl, octanoyl, nonanoyl, decanoyl, dodecanoyl, and octadecanoyl groups, and alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, and butoxy groups.

[0059] In one embodiment, from the viewpoint of further accelerating the curing reaction of the adhesive composition and providing the adhesive composition with better pot life, heat resistance, and chemical resistance to the electrolyte, the organoaluminum compound (C) is preferably an aluminum chelate compound in which a keto-enol tautomer is coordinated.

[0060] Examples of aluminum chelate compounds include aluminum acetoacetate diisopropylate, aluminum ethyl acetoacetate diisopropylate, aluminum tris(ethyl acetoacetate), aluminum alkyl acetate diisopropylate, aluminum bis(ethyl acetoacetate) monoacetylacetonate, and aluminum tris(acetylacetonate), and these can be used either alone or in combination of two or more.

[0061] In one embodiment, the content of the organoaluminum compound (C) is preferably 0.01 to 2 parts by mass, more preferably 0.05 to 1.5 parts by mass, even more preferably 0.1 to 1.25 parts by mass, even more preferably 0.2 to 1.0 part by mass, and particularly preferably 0.3 to 0.95 parts by mass, relative to 100 parts by mass of the acid-modified polyolefin (A). When the content of the organoaluminum compound (C) is 0.01 to 2 parts by mass relative to 100 parts by mass of the acid-modified polyolefin (A), the curing reaction of the adhesive composition is further accelerated, and the pot life, heat resistance, and chemical resistance to electrolytes of the adhesive composition are further improved.

[0062] In one embodiment, the content of the organoaluminum compound (C) is preferably 0.05 to 30 parts by mass, more preferably 0.25 to 20 parts by mass, even more preferably 0.5 to 16 parts by mass, still more preferably 0.9 to 12 parts by mass, still more preferably 1.0 to 10 parts by mass, particularly preferably 1.1 to 8 parts by mass, and most preferably 1.2 to 6 parts by mass, relative to 100 parts by mass of the polyfunctional polyisocyanate curing agent (B).

[0063] <Organic Solvent (D)> The adhesive composition of the present embodiment may further contain an organic solvent (D). Examples of the organic solvent (D) include aromatic hydrocarbon solvents such as benzene, toluene, and xylene; aliphatic hydrocarbon solvents such as hexane, heptane, octane, and decane; alicyclic hydrocarbon solvents such as cyclohexane, cyclohexene, methylcyclohexane, and ethylcyclohexane; halogenated hydrocarbon solvents such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform; alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; and acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanone, hexanone, cyclohexanone, isophorone, and acetophenone. Ketone-based solvents include cellosolve-based solvents such as methyl cellosolve and ethyl cellosolve; ester-based solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate and butyl formate; and glycol ether-based solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso-butyl ether, triethylene glycol mono-n-butyl ether and tetraethylene glycol mono-n-butyl ether, and the like. These may be used either alone or in combination of two or more.

[0064] In one embodiment, the content of the organic solvent (D) is preferably 80 to 2000 parts by mass, more preferably 100 to 1600 parts by mass, even more preferably 150 to 1200 parts by mass, even more preferably 200 to 1000 parts by mass, still more preferably 300 to 950 parts by mass, particularly preferably 400 to 900 parts by mass, and most preferably 425 to 800 parts by mass, relative to 100 parts by mass of the acid-modified polyolefin (A). When the content of the organic solvent (D) is 80 to 2000 parts by mass relative to 100 parts by mass of the acid-modified polyolefin (A), the solution state of the base agent and the pot life of the adhesive composition are improved.

[0065] In one embodiment, from the viewpoint of further improving the solution state of the main component and the pot life of the adhesive composition, the organic solvent (D) preferably comprises a solvent (D1) and a solvent (D2), the solvent (D1) being at least one solvent (D1) selected from the group consisting of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and halogenated hydrocarbon solvents, and the solvent (D2) being at least one solvent selected from the group consisting of alcohol solvents, ketone solvents, ester solvents, and glycol ether solvents.

[0066] In one embodiment, from the viewpoint of further improving the solution state of the main component and the pot life of the adhesive composition, the organic solvent (D) comprises a solvent (D1) and a solvent (D2), and it is more preferred that the solvent (D1) is an aromatic hydrocarbon solvent or an alicyclic hydrocarbon solvent, and the solvent (D2) is a ketone solvent.

[0067] In one embodiment, from the viewpoint of further improving the solution state of the main component and the pot life of the adhesive composition, the organic solvent (D) comprises a solvent (D1) and a solvent (D2), and it is particularly preferred that the solvent (D1) is an alicyclic hydrocarbon solvent and the solvent (D2) is a ketone solvent.

[0068] In one embodiment, the mass ratio of solvent (D1) to solvent (D2) (solvent (D1) / solvent (D2)) is, from the viewpoint of further improving the solution state of the main component and the pot life of the adhesive composition, preferably solvent (D1) / solvent (D2)=50 / 50 to 97 / 3, more preferably solvent (D1) / solvent (D2)=55 / 45 to 95 / 5, even more preferably solvent (D1) / solvent (D2)=60 / 40 to 90 / 10, and particularly preferably solvent (D1) / solvent (D2)=70 / 30 to 80 / 20.

[0069] <Acid anhydride group-containing monomer (E)> The adhesive composition of the present embodiment may further contain an acid anhydride group-containing monomer (E). By containing the acid anhydride group-containing monomer (E), heat resistance is further improved.

[0070] In one embodiment, the molecular weight of the acid anhydride group-containing monomer (E) is preferably 100 g / mol or more and 500 g / mol or less. The molecular weight of the acid anhydride group-containing monomer (E) is more preferably 150 g / mol or more, and even more preferably 200 g / mol or more. The molecular weight of the acid anhydride group-containing monomer (E) is more preferably 450 g / mol or less, and even more preferably 400 g / mol or less. When the molecular weight of the acid anhydride group-containing monomer (E) is 500 g / mol or less, the compatibility between the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) is improved, and the adhesive properties of the adhesive composition are further improved. When the molecular weight of the acid anhydride group-containing monomer (E) is 100 g / mol or more, the acid anhydride group-containing monomer (E) does not bleed out, and the adhesive properties and heat resistance of the adhesive composition tend to be further improved.

[0071] In one embodiment, the acid value of the acid anhydride group-containing monomer (E) is preferably 150 mgKOH / g or more and 800 mgKOH / g or less. The acid value of the acid anhydride group-containing monomer (E) is more preferably 250 mgKOH / g or more, even more preferably 300 mgKOH / g or more. The acid value of the acid anhydride group-containing monomer (E) is more preferably 600 mgKOH / g or less, even more preferably 500 mgKOH / g or less. When the acid value of the acid anhydride group-containing monomer (E) is 800 mgKOH / g or less, the acid anhydride group-containing monomer (E) does not bleed out before the adhesive composition cures, and the adhesive properties and heat resistance of the adhesive composition tend to be even better. Furthermore, when the acid value of the acid anhydride group-containing monomer (E) is 150 mgKOH / g or more, the chemical resistance of the adhesive composition to the electrolyte solution is even better.

[0072] The acid anhydride group-containing monomer (E) usually has one or more acid anhydride groups per molecule, preferably one acid anhydride group per molecule. In one embodiment, the acid anhydride group contained in the acid anhydride group-containing monomer (E) is preferably an acid anhydride group having a cyclic structure, more preferably a group derived from succinic anhydride, a group derived from maleic anhydride, or a group derived from glutaric anhydride, and even more preferably a group derived from succinic anhydride. In this specification, the group derived from acid anhydride usually means a monovalent group having a structure in which one hydrogen atom (a hydrogen atom possessed by a hydrocarbon group) has been removed from an acid anhydride, and for example, the group derived from succinic anhydride means a monovalent group having a structure in which one hydrogen atom has been removed from succinic anhydride.

[0073] Examples of the acid anhydride group-containing monomer (E) include succinic anhydride, maleic anhydride, glutaric anhydride, butylsuccinic anhydride, hexylsuccinic anhydride, octylsuccinic anhydride, dodecylsuccinic anhydride, dodecenylsuccinic anhydride, tetrapropenylsuccinic anhydride, butylmaleic anhydride, pentylmaleic anhydride, hexylmaleic anhydride, octylmaleic anhydride, decylmaleic anhydride, dodecylmaleic anhydride, butylglutamic anhydride, hexylglutamic anhydride, heptylglutamic anhydride, and octylglutamic anhydride. Examples of suitable anhydride-containing compounds include compounds having an alkyl chain and an acid anhydride group, such as hydrate, decyl glutamic anhydride, and dodecyl glutamic anhydride; and compounds having an alicyclic structure or an aromatic ring structure and an acid anhydride group, such as pyromellitic anhydride, trimellitic anhydride, benzophenone tetracarboxylic dianhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylpentahydrophthalic anhydride, methyltrihydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexene dicarboxylic anhydride, HET anhydride, and tetrabromophthalic anhydride. These compounds may be used alone or in combination of two or more. Among these, dodecenyl succinic anhydride is particularly preferred from the viewpoint of ease of handling. Dodecenyl succinic anhydride is usually liquid at room temperature.

[0074] In one embodiment, the acid anhydride group-containing monomer (E) preferably has a hydrocarbon group, and more preferably the hydrocarbon group is bonded to an acid anhydride group. The hydrocarbon group is more preferably linear. When the acid anhydride group-containing monomer (E) contains a hydrocarbon group, the compatibility between the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) is further improved, and the adhesive composition tends to have particularly good pot life, adhesion, heat resistance, and chemical resistance to electrolytes.

[0075] When the acid anhydride group-containing monomer (E) has a hydrocarbon group, the hydrocarbon group preferably has 3 or more and 20 or less carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), more preferably 5 or more and 18 or less (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18), even more preferably 8 or more and 16 or less (8, 9, 10, 11, 12, 13, 14, 15, or 16), and particularly preferably 11 or more and 15 or less (11, 12, 13, 14, or 15). When the hydrocarbon group has 3 or more and 20 carbon atoms, the compatibility with the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) is further improved, and the adhesive composition is further improved in pot life, adhesion, and chemical resistance to electrolytic solutions.

[0076] In one embodiment, the acid anhydride group-containing monomer (E) is preferably a linear alkyl group having 3 to 20 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), more preferably a linear alkyl group having 5 to 18 carbon atoms (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18), still more preferably a linear alkyl group having 8 to 16 carbon atoms (8, 9, 10, 11, 12, 13, 14, 15, or 16), particularly preferably a linear alkyl group having 11 to 15 carbon atoms (11, 12, 13, 14, or 15).

[0077] In one embodiment, the content of the acid anhydride group-containing monomer (E) is preferably 0.1 parts by mass or more per 100 parts by mass of the acid-modified polyolefin (A). When the content of the acid anhydride group-containing monomer (E) is 0.1 parts by mass or more per 100 parts by mass of the acid-modified polyolefin (A), the synergistic effect of the polyfunctional polyisocyanate curing agent (B) and the acid anhydride group-containing monomer (E) further improves the heat resistance and chemical resistance to the electrolyte of the adhesive composition. The content of the acid anhydride group-containing monomer (E) is more preferably 0.3 parts by mass or more, even more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more per 100 parts by mass of the acid-modified polyolefin (A).

[0078] In one embodiment, the content of the acid anhydride group-containing monomer (E) is preferably 20 parts by mass or less relative to 100 parts by mass of the acid-modified polyolefin (A). When the content of the acid anhydride group-containing monomer (E) is 20 parts by mass or less relative to 100 parts by mass of the acid-modified polyolefin (A), the adhesive composition tends to have good heat resistance and chemical resistance to the adhesive electrolyte, and particularly tends to exhibit excellent chemical resistance to the electrolyte over a long period of time. More preferably, it is 10 parts by mass or less, even more preferably 8 parts by mass or less, and particularly preferably 5 parts by mass or less.

[0079] In one embodiment, from the viewpoint of further improving the adhesive properties, heat resistance, and chemical resistance to the electrolyte of the adhesive composition, the content of the acid anhydride group-containing monomer (E) is preferably 0.1 parts by mass or more and 20 parts by mass or less, more preferably 0.3 parts by mass or more and 10 parts by mass or less, and even more preferably 0.5 parts by mass or more and 8 parts by mass or less, or 1 part by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the acid-modified polyolefin (A).

[0080] The adhesive composition of this embodiment contains, as essential components, an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organoaluminum compound (C). When the adhesive composition of this embodiment contains an organic solvent (D), the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) may be dissolved or dispersed in the organic solvent (D), and are preferably dissolved in the organic solvent (D) in order to further improve pot life.

[0081] The adhesive composition of the present embodiment may contain, in addition to the acid-modified polyolefin (A), the polyfunctional polyisocyanate curing agent (B), and the organoaluminum compound (C), various tackifiers, thermoplastic elastomers, and plasticizers, as long as the properties of the present invention are not impaired. These may be used alone or in combination of two or more.

[0082] The tackifier is not particularly limited, but examples thereof include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymer petroleum resins, and hydrogenated petroleum resins, and these may be used either alone or in combination of two or more.

[0083] Examples of the thermoplastic elastomer include styrene-based elastomers such as styrene-ethylene-butylene-styrene copolymer resin and styrene-ethylene-propylene-styrene; and olefin-based elastomers such as ethylene-propylene copolymer resin, ethylene-butene copolymer resin, ethylene-vinyl acetate copolymer resin and ethylene-ethyl acrylate copolymer resin, and the like. These may be used either alone or in combination of two or more.

[0084] Examples of the plasticizer include liquid rubbers such as polyisoprene and polybutene; and process oils, which may be used either alone or in combination of two or more.

[0085] The adhesive composition of this embodiment can be used in combination with the polyfunctional polyisocyanate curing agent (B) and various curing agents other than the polyfunctional polyisocyanate curing agent (B), as long as the performance of the present invention is not impaired. Examples of curing agents other than the polyfunctional polyisocyanate curing agent (B) include curing agents having a functional group that reacts with the acid-modified polyolefin (A). Examples of curing agents other than the polyfunctional polyisocyanate curing agent (B) include epoxy resins, carbodiimide compounds, oxazoline compounds, coupling agents, etc.

[0086] Examples of epoxy resins include glycidyl ester types such as hexahydrophthalic acid glycidyl ester and dimer acid glycidyl ester; alicyclic or aliphatic epoxides such as triglycidyl isocyanurate, 3,4-epoxycyclohexylmethylcarboxylate, epoxidized polybutadiene and epoxidized soybean oil; glycidyl ether type epoxy resins; and glycidyl amine type epoxy resins.

[0087] Examples of the carbodiimide compound include monocarbodiimide compounds such as dimethylcarbodiimide, diisopropylcarbodiimide, dicyclohexylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, and di-β-naphthylcarbodiimide; and polycarbodiimide compounds obtained by carrying out a decarboxylation condensation reaction of an organic diisocyanate such as an aliphatic diisocyanate, an aromatic diisocyanate, or an alicyclic diisocyanate in the presence of a condensation catalyst in the absence of a solvent or in an inert solvent.

[0088] Examples of the oxazoline compound include monooxazoline compounds such as 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, and 2,4-diphenyl-2-oxazoline; and dioxazoline compounds such as 2,2'-(1,3-phenylene)-bis(2-oxazoline), 2,2'-(1,2-ethylene)-bis(2-oxazoline), 2,2'-(1,4-butylene)-bis(2-oxazoline), and 2,2'-(1,4-phenylene)-bis(2-oxazoline).

[0089] Examples of the coupling agent include a silane coupling agent and a titanate coupling agent.

[0090] The adhesive composition of the present embodiment may contain a keto-enol tautomer compound in addition to the acid-modified polyolefin (A), the polyfunctional polyisocyanate curing agent (B), and the organoaluminum compound (C), as long as the performance of the present invention is not impaired.

[0091] Examples of keto-enol tautomer compounds include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate, and β-diketones such as acetylacetone, 2,4-hexanedione, and benzoylacetone. These compounds can protect the isocyanate groups of the polyfunctional polyisocyanate curing agent (B), suppress a significant increase in viscosity and gelation of the adhesive composition, and further improve the pot life of the adhesive composition.

[0092] When a keto-enol tautomer compound is contained, the content of the keto-enol tautomer compound is preferably 0.1 parts by mass or more and 3 parts by mass or less per 100 parts by mass of the polyfunctional polyisocyanate (B).

[0093] In addition to the acid-modified polyolefin (A), the polyfunctional polyisocyanate curing agent (B), and the organoaluminum compound (C), the adhesive composition of this embodiment may contain various additives, such as flame retardants, pigments, antiblocking agents, and fillers, as long as the additives do not impair the performance of the present invention.

[0094] In one embodiment, the content of the organozirconium compound or organotin compound in the adhesive composition of the present embodiment is preferably less than 0.5 parts by mass, more preferably 0.3 parts by mass or less, even more preferably 0.1 parts by mass or less, still more preferably 0.05 parts by mass or less, particularly preferably 0.01 parts by mass or less, and most preferably 0 part by mass, per 100 parts by mass of the acid-modified polyolefin (A).

[0095] 2. Laminate The laminate of this embodiment can be obtained by bonding a polyolefin resin substrate and a metal substrate with the adhesive composition of this embodiment.

[0096] The laminate of this embodiment can be manufactured using conventionally known laminate manufacturing techniques. For example, the adhesive composition of this embodiment is applied to the surface of a metal substrate using a roll coater, bar coater, or the like, and then dried. After drying, while the layer of the adhesive composition of this embodiment (adhesive layer) formed on the surface of the metal substrate is in a molten state, a polyolefin resin substrate is laminated (laminated) to the surface of the adhesive layer to obtain a laminate. The thickness of the adhesive layer formed using the adhesive composition of this embodiment is preferably 0.5 μm to 10 μm, more preferably 0.8 μm to 9.5 μm, and even more preferably 1.0 μm to 9 μm.

[0097] <Polyolefin Resin Substrate> As the polyolefin resin substrate, a wide variety of known polyolefin resins commonly used in this field can be used. Examples of polyolefin resin substrates include polyethylene, polypropylene, and ethylene-propylene copolymers. Among these, the polyolefin resin substrate is preferably polypropylene, and more preferably unstretched polypropylene (cast polypropylene) film. The thickness of the polyolefin resin substrate is preferably 20 μm to 100 μm, more preferably 25 μm to 95 μm, and even more preferably 30 μm to 90 μm. Note that the polyolefin resin substrate may be blended with pigments or various additives as needed, or may be subjected to a surface treatment.

[0098] <Metal Substrate> As the metal substrate, various metals and alloys thereof, such as aluminum, copper, steel, chromium, zinc, duralumin, and die-cast metals, can be used. The metal substrate may be in the form of a metal foil, a rolled steel plate, a panel, a pipe, a can, a cap, or the like. From the viewpoint of workability, aluminum foil is preferred as the metal substrate. Although it varies depending on the intended use, the metal substrate can be used in the form of a sheet, typically having a thickness of 0.01 to 10 mm, preferably 0.02 to 5 mm. The surface of the metal substrate may be previously surface-treated or may remain untreated.

[0099] 3. Packaging Material for Lithium-ion Batteries The packaging material for lithium-ion batteries of this embodiment includes the laminate of this embodiment. The packaging material for lithium-ion batteries is an exterior body that packages the lithium-ion battery body.

[0100] In one embodiment, the content of the laminate in the packaging material for lithium ion batteries is usually more than 50% by mass, preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more.

[0101] In one embodiment, the packaging material for lithium ion batteries is most preferably made of a laminate.

[0102] The present invention provides the following aspects of the invention. Item 1. An adhesive composition comprising an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organoaluminum compound (C), wherein the weight average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000. Item 2. The adhesive composition according to Item 1, wherein the content of the polyfunctional polyisocyanate curing agent (B) is 0.5 to 70 parts by mass per 100 parts by mass of the acid-modified polyolefin (A). Item 3. The adhesive composition according to Item 1 or 2, wherein the content of the organoaluminum compound (C) is 0.01 to 2 parts by mass per 100 parts by mass of the acid-modified polyolefin (A). Item 4. The adhesive composition according to any one of Items 1 to 3, wherein the acid-modified polyolefin (A) is a graft polymer having a structure in which at least one selected from an α,β-unsaturated carboxylic acid and an acid anhydride thereof is grafted to a polyolefin. Item 5. Item 6. The adhesive composition according to any one of Items 1 to 4, wherein the acid-modified polyolefin (A) has an acid value of 2 to 50 mgKOH / g. Item 7. The adhesive composition according to any one of Items 1 to 5, wherein the organoaluminum compound (C) is an aluminum alcoholate compound and / or an aluminum chelate compound. Item 8. The adhesive composition according to any one of Items 1 to 6, further comprising an organic solvent (D). Item 9. The adhesive composition according to Item 7, wherein the organic solvent (D) consists of solvent (D1) and solvent (D2), wherein solvent (D1) is at least one solvent selected from the group consisting of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and halogenated hydrocarbon solvents, and solvent (D2) is at least one solvent selected from the group consisting of alcohol solvents, ketone solvents, ester solvents, and glycol ether solvents. Item 10. Item 10. The adhesive composition according to any one of Items 1 to 9, further comprising an acid anhydride group-containing monomer (E).Item 11. The adhesive composition according to Item 10, wherein the content of the acid anhydride group-containing monomer (E) is 0.1 to 20 parts by mass relative to 100 parts by mass of the acid-modified polyolefin (A). Item 12. The adhesive composition according to Item 10 or 11, wherein the acid anhydride group-containing monomer (E) contains a hydrocarbon group having 3 to 20 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20). Item 13. The adhesive composition according to any one of Items 1 to 12, wherein the content of the polyfunctional polyisocyanate curing agent (B) relative to 100 parts by mass of the acid-modified polyolefin (A) is more preferably 1 to 65 parts by mass, even more preferably 2 to 60 parts by mass, even more preferably 3 to 55 parts by mass, even more preferably 6 to 50 parts by mass, particularly preferably 10 to 45 parts by mass, and most preferably 15 to 40 parts by mass. Item 14. The adhesive composition according to any one of Items 1 to 13, wherein the content of the organoaluminum compound (C) per 100 parts by mass of the acid-modified polyolefin (A) is more preferably 0.05 to 1.5 parts by mass, even more preferably 0.1 to 1.25 parts by mass, even more preferably 0.2 to 1.0 part by mass, and particularly preferably 0.3 to 0.95 parts by mass. Item 15. The adhesive composition according to any one of Items 4 to 14, wherein the polyolefin is usually at least one selected from the group consisting of homopolyethylene, homopolypropylene, and propylene-α-olefin copolymer, preferably homopolypropylene and / or propylene-α-olefin copolymer, more preferably propylene-α-olefin copolymer. Item 16. The adhesive composition according to Item 15, wherein the α-olefin in the propylene-α-olefin copolymer is preferably ethylene and / or 1-butene, more preferably 1-butene. Item 17. Item 17. The adhesive composition according to item 15 or 16, wherein the content of the propylene component in the propylene-α-olefin copolymer is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% or more.Item 18. The adhesive composition according to any one of Items 4 to 17, wherein the α,β-unsaturated carboxylic acid and its acid anhydride are typically maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, mesaconic acid, citraconic acid, citraconic anhydride, aconitic acid, or aconitic anhydride, and preferably maleic anhydride. Item 19. The adhesive composition according to any one of Items 1 to 18, wherein the Mw of the acid-modified polyolefin (A) is preferably in the range of 20,000 to 180,000, more preferably 30,000 to 160,000, particularly preferably 40,000 to 140,000, and most preferably 50,000 to 110,000. Item 20. Item 21. The adhesive composition according to any one of Items 1 to 20, wherein the content of the acid-modified chlorinated polyolefin in the adhesive composition is preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, and most preferably 0% by mass. Item 22. The adhesive composition according to any one of Items 1 to 20, wherein the acid-modified polyolefin (A) is preferably maleic anhydride-modified homopolypropylene and / or maleic anhydride-modified propylene-1-butene copolymer, more preferably maleic anhydride-modified homopolypropylene or maleic anhydride-modified propylene-1-butene copolymer. Item 22. The adhesive composition according to any one of Items 1 to 21, wherein the content of the polyfunctional polyisocyanate curing agent (B) relative to 100 parts by mass of the acid-modified polyolefin (A) is more preferably 1 to 65 parts by mass, even more preferably 2 to 60 parts by mass, even more preferably 3 to 55 parts by mass, even more preferably 6 to 50 parts by mass, particularly preferably 10 to 45 parts by mass, and most preferably 15 to 40 parts by mass. Item 23. The adhesive composition according to any one of Items 1 to 22, wherein the content of the organoaluminum compound (C) relative to 100 parts by mass of the acid-modified polyolefin (A) is more preferably 0.05 to 1.5 parts by mass, even more preferably 0.1 to 1.25 parts by mass, even more preferably 0.2 to 1.0 parts by mass, and particularly preferably 0.3 to 0.95 parts by mass.Item 24. The adhesive composition according to any one of Items 1 to 23, wherein the acid value of the acid-modified polyolefin (A) is more preferably 3 to 45 mgKOH / g, even more preferably 5 to 40 mgKOH / g, and particularly preferably 7 to 35 mgKOH / g. Item 25. The adhesive composition according to any one of Items 1 to 24, wherein the polyfunctional polyisocyanate curing agent (B) is preferably a diisocyanate compound or a derivative of a diisocyanate compound, more preferably a derivative of a diisocyanate compound. Item 26. Item 26. The adhesive composition according to any one of Items 1 to 24, wherein the polyfunctional polyisocyanate curing agent (B) is preferably an isocyanurate-modified diisocyanate compound and / or a biuret-modified diisocyanate compound, more preferably at least one selected from the group consisting of an isocyanurate-modified hexamethylene diisocyanate, an adduct-modified hexamethylene diisocyanate, a biuret-modified hexamethylene diisocyanate, a uretdione-modified hexamethylene diisocyanate, and an allophanate-modified hexamethylene diisocyanate, and particularly preferably an isocyanurate-modified hexamethylene diisocyanate and / or a biuret-modified hexamethylene diisocyanate. Item 27. The adhesive composition according to any one of Items 6 to 26, wherein the aluminum alcoholate compound is at least one selected from the group consisting of aluminum ethylate, aluminum isopropylate, aluminum diisopropylate monosec-butylate, and aluminum sec-butylate. Item 28. The adhesive composition according to any one of Items 6 to 27, wherein the organoaluminum compound (C) is an aluminum chelate compound. Item 29. The adhesive composition according to Item 28, wherein the aluminum chelate compound is at least one selected from the group consisting of aluminum acetoacetate diisopropylate, aluminum ethyl acetoacetate diisopropylate, aluminum tris(ethyl acetoacetate), aluminum alkyl acetate diisopropylate, aluminum bis(ethyl acetoacetate) monoacetylacetonate, and aluminum tris(acetylacetonate).Item 30. The adhesive composition according to any one of Items 1 to 29, wherein the content of the organoaluminum compound (C) per 100 parts by mass of the acid-modified polyolefin (A) is more preferably 0.05 to 1.5 parts by mass, even more preferably 0.1 to 1.25 parts by mass, even more preferably 0.2 to 1.0 parts by mass, and particularly preferably 0.3 to 0.95 parts by mass. Item 31. The adhesive composition according to any one of Items 1 to 30, wherein the content of the organoaluminum compound (C) per 100 parts by mass of the polyfunctional polyisocyanate curing agent (B) is preferably 0.05 to 30 parts by mass, more preferably 0.25 to 20 parts by mass, even more preferably 0.5 to 16 parts by mass, even more preferably 0.9 to 12 parts by mass, even more preferably 1.0 to 10 parts by mass, particularly preferably 1.1 to 8 parts by mass, and most preferably 1.2 to 6 parts by mass. Item 32. Item 32. The adhesive composition according to any one of Items 7 to 31, wherein the content of the organic solvent (D) relative to 100 parts by mass of the acid-modified polyolefin (A) is preferably 80 to 2,000 parts by mass, more preferably 100 to 1,600 parts by mass, even more preferably 150 to 1,200 parts by mass, even more preferably 200 to 1,000 parts by mass, still more preferably 300 to 950 parts by mass, particularly preferably 400 to 900 parts by mass, and most preferably 425 to 800 parts by mass. Item 33. The adhesive composition according to any one of Items 7 to 32, wherein the organic solvent (D) consists of solvent (D1) and solvent (D2), wherein solvent (D1) is an aromatic hydrocarbon solvent or an alicyclic hydrocarbon solvent, and solvent (D2) is a ketone solvent. Item 34. Item 35. The adhesive composition according to any one of Items 8 to 34, wherein the mass ratio of the solvent (D1) to the solvent (D2) (solvent (D1) / solvent (D2)) is more preferably 55 / 45 to 95 / 5, even more preferably 60 / 40 to 90 / 10, and particularly preferably 70 / 30 to 80 / 20.Item 36. The adhesive composition according to any one of Items 10 to 35, wherein the content of the acid anhydride group-containing monomer (E) is more preferably 0.3 parts by mass to 10 parts by mass, even more preferably 0.5 parts by mass to 8 parts by mass, or 1 part by mass to 5 parts by mass, per 100 parts by mass of the acid-modified polyolefin (A). Item 37. The adhesive composition according to any one of Items 10 to 36, wherein the acid anhydride group contained in the acid anhydride group-containing monomer (E) is preferably an acid anhydride group having a cyclic structure, more preferably a group derived from succinic anhydride, a group derived from maleic anhydride, or a group derived from glutaric anhydride, and even more preferably a group derived from succinic anhydride. Item 38. Item 39. The adhesive composition according to any one of Items 10 to 38, wherein the molecular weight of the acid anhydride group-containing monomer (E) is preferably 100 g / mol or more and 500 g / mol or less, more preferably 150 g / mol or more and 450 g / mol or less, and even more preferably 200 g / mol or more and 400 g / mol or less. Item 39. The adhesive composition according to any one of Items 10 to 38, wherein the acid value of the acid anhydride group-containing monomer (E) is preferably 150 mgKOH / g or more and 800 mgKOH / g or less, more preferably 250 mgKOH / g or more and 600 mgKOH / g or less, and even more preferably 300 mgKOH / g or more and 500 mgKOH / g or less. Item 40. Item 40. The adhesive composition according to any one of Items 10 to 39, wherein the acid anhydride group-containing monomer (E) preferably has a linear alkyl group having 3 to 20 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20), more preferably a linear alkyl group having 5 to 18 carbon atoms (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18), even more preferably a linear alkyl group having 8 to 16 carbon atoms (8, 9, 10, 11, 12, 13, 14, 15, or 16), and particularly preferably a linear alkyl group having 11 to 15 carbon atoms (11, 12, 13, 14, or 15).Item 41. The acid anhydride group-containing monomer (E) is succinic anhydride, maleic anhydride, glutaric anhydride, butylsuccinic anhydride, hexylsuccinic anhydride, octylsuccinic anhydride, dodecylsuccinic anhydride, dodecenylsuccinic anhydride, tetrapropenylsuccinic anhydride, butylmaleic anhydride, pentylmaleic anhydride, hexylmaleic anhydride, octylmaleic anhydride, decylmaleic anhydride, dodecylmaleic anhydride, butylglutamic anhydride, hexylglutamic anhydride, heptylglutamic anhydride, octylglutamic anhydride, Item 41. The adhesive composition according to any one of Items 10 to 40, wherein the acid anhydride group-containing monomer (E) is at least one selected from the group consisting of phthalic anhydride, methyltetrahydrophthalic anhydride, methylpentahydrophthalic anhydride, methyltrihydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexene dicarboxylic anhydride, HET anhydride, and tetrabromophthalic anhydride. Item 42. The adhesive composition according to any one of Items 10 to 40, wherein the acid anhydride group-containing monomer (E) is dodecenylsuccinic anhydride. Item 43. Item 43. The adhesive composition according to any one of items 1 to 42, wherein the content of the organozirconium compound or organotin compound in the adhesive composition is preferably less than 0.5 parts by mass, more preferably 0.3 parts by mass or less, even more preferably 0.1 parts by mass or less, even more preferably 0.05 parts by mass or less, particularly preferably 0.01 parts by mass or less, and most preferably 0 parts by mass, per 100 parts by mass of the acid-modified polyolefin (A). Item 44. The adhesive composition according to any one of items 1 to 43, which is used for bonding a polyolefin resin substrate and a metal substrate. Item 45. A laminate obtained by bonding a polyolefin resin substrate and a metal substrate with the adhesive composition according to any one of items 1 to 43. Item 46. A packaging material for lithium ion batteries, comprising the laminate according to item 45.

[0103] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. Hereinafter, "room temperature" means a temperature within the range of 20°C to 25°C.

[0104] Measurement of Acid Value The acid value (mg KOH / g) of the acid-modified polyolefin (A) refers to the amount of KOH required to neutralize 1 g of the acid-modified polyolefin (A). The acid value of the acid-modified polyolefin (A) was measured in accordance with the test method of JIS K 0070 (1992). Specifically, 1 g of the acid-modified polyolefin (A) was dissolved in 100 g of xylene adjusted to 100 ° C., and then titrated with a 0.1 mol / L potassium hydroxide ethanol solution (trade name "0.1 mol / L ethanolic potassium hydroxide solution", manufactured by Wako Pure Chemical Industries, Ltd.) at 100 ° C. using phenolphthalein as an indicator. At this time, the amount of potassium hydroxide required for the titration was converted into mg to calculate the acid value (mg KOH / g) of the acid-modified polyolefin (A).

[0105] Measurement of Acetone Extractable Component Ratio The acetone extractable component ratio (mass%) of the acid-modified polyolefin (A) was measured by refluxing with acetone for 2 hours using a Soxhlet extractor. Specifically, 50 g of the acid-modified polyolefin (A) was weighed into a cylindrical filter paper and placed in a Soxhlet extraction tube. After that, a condenser was attached to a flat-bottom flask containing 1100 mL of acetone, and the tube was assembled and refluxed in a water bath at 90 ° C for 2 hours to perform acetone extraction. The cylindrical filter paper was then removed, the acetone extract in the flat-bottom flask was distilled off, and the weight (g) of the residue after further drying under reduced pressure at 100 ° C for 1 hour was measured, and the acetone extractable component ratio of the acid-modified polyolefin (A) was calculated using the following formula: Acetone extractable component ratio (mass%) of the acid-modified polyolefin (A) = (weight of extracted residue / sample amount) × 100

[0106] Measurement of Storage Modulus (E') at 25°C The storage modulus (E') (MPa) of the acid-modified polyolefin (A) was measured in accordance with the test method of JIS K 7244-4 (1999). Specifically, the acid-modified polyolefin (A) was dissolved in a mixed solvent of cyclohexane / methyl ethyl ketone in a ratio of 80% by mass / 20% by mass to obtain a solution. The obtained solution was applied to a Teflon (registered trademark) sheet to a film thickness of approximately 50 μm, and then dried to obtain a dried coating film. The coating film was cut into a width of 5 mm and a length of 25 mm to obtain a test specimen. The test specimen was heated from -50°C to 80°C at a rate of 5°C / min using a dynamic viscoelasticity measuring device (manufactured by IT Measurement & Control Co., Ltd., "DVA-200") at a frequency of 10 Hz, and the storage modulus (E') value (MPa) of the test specimen at 25°C was measured.

[0107] Measurement of Tensile Breaking Elongation (Eb) at 25°C The tensile breaking elongation (Eb) (%) of the acid-modified polyolefin (A) was measured in accordance with the test method of JIS K 7161 (2014). Specifically, the acid-modified polyolefin (A) was dissolved in a mixed solvent of cyclohexane and methyl ethyl ketone in a ratio of 80% by mass and 20% by mass to obtain a solution. The obtained solution was applied to a Teflon (registered trademark) sheet to a film thickness of 50 μm and dried to obtain a dried coating film. The coating film was cut into a width of 15 mm and a length of 70 mm to obtain a test specimen. The obtained test specimen was subjected to a tensile test using a tensile tester (Tensilon RTM-100 manufactured by Orientec Corporation) at 25°C, with a chuck distance of 40 mm and a pulling rate of 50 mm / min. The tensile breaking elongation (%) at which the test specimen broke was calculated using the following formula: Tensile elongation at break (Eb) (%) of acid-modified polyolefin (A) = [(length of test piece at break - length of test piece before test) / length of test piece at break] x 100

[0108] Measurement of Weight Average Molecular Weight (Mw) The weight average molecular weight (Mw) of the acid-modified polyolefin (A) was measured using a gel permeation chromatograph Alliance e2695 manufactured by Nippon Waters Co., Ltd. The measurement conditions for gel permeation chromatography (GPC) were as follows: The calibration curve was obtained by dissolving each of the following standard polystyrenes, manufactured by GL Sciences: "Molecular weight standard (lipid-soluble polymer) MW 500: Model 2012-2," "Molecular weight standard (lipid-soluble polymer) MW 2,000: Model 2012-5," "Molecular weight standard (lipid-soluble polymer) MW 10,000: Model 2012-9," "Molecular weight standard (lipid-soluble polymer) MW 20,000: Model 2013-1," "Molecular weight standard (lipid-soluble polymer) MW 50,000: Model 2013-3," and "Molecular weight standard (lipid-soluble polymer) MW 200,000: Model 2013-7," at a concentration of 0.5% to prepare a tetrahydrofuran solution, filtering the solution, placing it in a vial, and measuring the solution. <GPC measurement conditions> Standard substance: polystyrene resin (weight average molecular weight 500, 2,000, 50,000, 200,000) Concentration of acid-modified polyolefin (A): 0.5 mass% Mobile phase: tetrahydrofuran (THF) Column: Shodex KF-806 + KF-803 Column temperature: 40°C Flow rate: 1.0 ml / min Detector: photodiode array detector (wavelength 254 nm = ultraviolet light)

[0109] Measurement of Melting Point (Tm) and Heat of Fusion (ΔH) The melting point (Tm) (°C) and heat of fusion (ΔH) (J / g) of the acid-modified polyolefin (A) were measured as follows. Specifically, using a differential scanning calorimeter (DSC) (manufactured by TA Instruments Japan, Q-2000), approximately 5 mg of the acid-modified polyolefin (A) as a sample was heated from -50°C to 250°C at a rate of 20°C / min, maintained in a molten state for 5 minutes, cooled at a rate of 5°C / min, maintained at -50°C for 5 minutes, and further heated from -50°C to 250°C at a rate of 5°C / min. The temperature at which the apex of the melting peak appeared when melted was taken as the melting point (Tm). The heat of fusion (ΔH) was calculated from the integrated value of this melting peak. When multiple peaks were detected during the measurement, the temperature of the peak detected on the highest temperature side and the integrated value of the peaks were taken as the melting point (Tm) and the heat of fusion (ΔH) of the acid-modified polyolefin (A), respectively.

[0110] <Production Examples of Acid-Modified Polyolefin (A)> Production Example 1 To a 1 L autoclave were added 100 parts by mass of propylene-1-butene copolymer (propylene component content 78 mol%, 1-butene component content 22 mol%, storage modulus at 25°C 320 MPa, tensile break elongation at 25°C 760%), 233 parts by mass of toluene, 1 part by mass of maleic anhydride, and 0.5 parts by mass of di-tert-butyl peroxide, and the mixture was heated to 140°C and then stirred for an additional 1 hour (here, this is referred to as "reacting" for 1 hour). The resulting reaction solution was then cooled to 100°C and poured with stirring into a container containing 717 parts by mass of toluene and 950 parts by mass of methyl ethyl ketone that had been preheated to 40°C. The mixture was then cooled to 40°C, stirred for an additional 30 minutes, and further cooled to 25°C to precipitate a resin (here, the process of pouring the reaction solution into a solvent such as methyl ethyl ketone with stirring and cooling to precipitate a resin is referred to as "reprecipitation"). The resin-containing slurry was then centrifuged to separate the acid-modified propylene-1-butene copolymer graft-polymerized with maleic anhydride, (poly)maleic anhydride, and low-molecular-weight substances. The acid-modified propylene-1-butene copolymer removed by centrifugation was then poured with stirring into a container containing 2,000 parts by mass of methyl ethyl ketone that had been preheated to 25°C, and stirring was continued for 1 hour. The slurry was then centrifuged to further separate the acid-modified propylene-1-butene copolymer, (poly)maleic anhydride, and low-molecular-weight substances. This procedure was repeated twice for purification (here, the procedure of adding the acid-modified propylene-1-butene copolymer extracted by centrifugation to methyl ethyl ketone with stirring and centrifuging again to enhance the purification is referred to as "reslurry"). After purification, the mixture was dried under reduced pressure at 70°C for 5 hours to obtain an acid-modified polyolefin, maleic anhydride-modified propylene-1-butene copolymer A-1 (propylene component content 78 mol%, 1-butene component content 22 mol%, acid value 2 mgKOH / g, acetone extractable component ratio 0.1 mass%, storage modulus at 25°C (E') 300 MPa, tensile elongation at break at 25°C (Eb) 600%, weight average molecular weight (Mw) 190,000, melting point (Tm) 78°C, heat of fusion (ΔH) 37 J / g).

[0111] Production Example 2 The same procedures as in Production Example 1 were carried out except that the amount of maleic anhydride charged was changed to 3 parts by mass, the number of reslurries was 1, and the amount of methyl ethyl ketone added during reslurry was changed to 1000 parts by mass, to obtain an acid-modified polyolefin maleic anhydride-modified propylene-1-butene copolymer A-2 (propylene component content 78 mol%, 1-butene component content 22 mol%, acid value 5 mg KOH / g, acetone extractable component ratio 1.8 mass%, storage modulus at 25 ° C. (E') 280 MPa, tensile elongation at break at 25 ° C. (Eb) 650%, weight average molecular weight (Mw) 180,000, melting point (Tm) 78 ° C., heat of fusion (ΔH) 36 J / g).

[0112] Production Example 3 The same procedures as in Production Example 1 were carried out except that the charged amounts of toluene were changed to 150 parts by mass, the charged amounts of maleic anhydride to 40 parts by mass, the charged amounts of di-tert-butyl peroxide to 8 parts by mass, the reaction time to 3 hours, the solvent used for reprecipitation to 700 parts by mass of methyl ethyl ketone, and the number of reslurries to 5, to obtain an acid-modified polyolefin, maleic anhydride-modified propylene-1-butene copolymer A-3 (propylene component content 78 mol%, 1-butene component content 22 mol%, acid value 48 mg KOH / g, acetone extractable component ratio 0.1 mass%, storage modulus at 25°C (E') 180 MPa, tensile break elongation at 25°C (Eb) 350%, weight average molecular weight (Mw) 31,000, melting point (Tm) 75°C, and heat of fusion (ΔH) 31 J / g).

[0113] Production Example 4 The amount of toluene charged was 150 parts by mass, the amount of maleic anhydride charged was 40 parts by mass, the amount of di-tert-butyl peroxide charged was 8 parts by mass, the reaction time was 3 hours, the solvent used for reprecipitation was 700 parts by mass of methyl ethyl ketone, the solvent used for reslurry was 1000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to 3. By the same procedure as in Production Example 1, except for changing the amount of reslurrying to 3, an acid-modified polyolefin, maleic anhydride-modified propylene-1-butene copolymer A-4 (propylene component content 78 mol%, 1-butene component content 22 mol%, acid value 48 mg KOH / g, acetone extractable component ratio 1.8 mass%, storage modulus at 25 ° C. (E') 150 MPa, tensile elongation at break at 25 ° C. (Eb) 300%, weight average molecular weight (Mw) 27,000, melting point (Tm) 75 ° C., heat of fusion (ΔH) 30 J / g) was obtained.

[0114] Production Example 5 The amount of toluene charged was 150 parts by mass, the amount of maleic anhydride charged was 20 parts by mass, the amount of di-tert-butyl peroxide charged was 6 parts by mass, the reaction time was 3 hours, the solvent used for reprecipitation was 700 parts by mass of methyl ethyl ketone, the solvent used for reslurry was 1000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to 2. By the same procedure as in Production Example 1, except for changing the amount of toluene charged to 150 parts by mass, the amount of maleic anhydride charged to 20 parts by mass of di-tert-butyl peroxide charged to 6 parts by mass, the reaction time was 3 hours, the solvent used for reprecipitation was 700 parts by mass of methyl ethyl ketone, the solvent used for reslurry was 1000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to 2. The same procedure was followed as in Production Example 1 to obtain an acid-modified polyolefin, maleic anhydride-modified propylene-1-butene copolymer A-5 (propylene component content 78 mol%, 1-butene component content 22 mol%, acid value 25 mg KOH / g, acetone extractable component ratio 0.9 mass%, storage modulus at 25 ° C. (E') 400 MPa, tensile elongation at break at 25 ° C. (Eb) 500%, weight average molecular weight (Mw) 60,000, melting point (Tm) 77 ° C., heat of fusion (ΔH) 35 J / g).

[0115] Production Example 6 A mixture of 100 parts by mass of propylene-1-butene copolymer (propylene content 70 mol%, 1-butene content 30 mol%, storage modulus at 25°C 52 MPa, tensile break elongation at 25°C 1050%), 150 parts by mass of toluene, 30 parts by mass of maleic anhydride, 6 parts by mass of di-tert-butyl peroxide, 700 parts by mass of methyl ethyl ketone as the solvent for reprecipitation, 1000 parts by mass of methyl ethyl ketone as the solvent for reslurry, and 1000 parts by mass of methyl ethyl ketone was used for the reaction. The same procedures as in Production Example 1 were carried out except that the number of times of rumbling was changed to two, thereby obtaining an acid-modified polyolefin, maleic anhydride-modified propylene-1-butene copolymer A-6 (propylene component content 70 mol%, 1-butene component content 30 mol%, acid value 25 mgKOH / g, acetone extractable component ratio 1.0 mass%, storage modulus at 25°C (E') 12 MPa, tensile break elongation at 25°C (Eb) 900%, weight average molecular weight (Mw) 60,000, melting point (Tm) 58°C, heat of fusion (ΔH) 7 J / g).

[0116] Production Example 7: 100 parts by mass of homopolypropylene (propylene homopolymer, storage modulus at 25°C 2100 MPa, tensile elongation at break at 25°C 900%), 150 parts by mass of toluene, 30 parts by mass of maleic anhydride, 6 parts by mass of di-tert-butyl peroxide, reaction time 3 hours, 700 parts by mass of methyl ethyl ketone as the solvent used for reprecipitation, 1000 parts by mass of methyl ethyl ketone as the solvent used for reslurry The same procedures as in Production Example 1 were carried out except that the amount of the olefin polymer was changed to 2, and the number of reslurries was changed to two. This resulted in an acid-modified polyolefin, maleic anhydride-modified homopolypropylene A-7 (acid value 25 mg KOH / g, acetone extractable component ratio 0.9 mass%, storage modulus at 25°C (E') 1800 MPa, tensile break elongation at 25°C (Eb) 60%, weight average molecular weight (Mw) 60,000, melting point (Tm) 75°C, heat of fusion (ΔH) 5 J / g).

[0117] Production Example 8 A mixture of 100 parts by mass of propylene-1-butene copolymer (propylene content 90 mol%, 1-butene content 10 mol%, storage modulus at 25°C 2720 MPa, tensile elongation at break at 25°C 400%), 186 parts by mass of toluene, 20 parts by mass of maleic anhydride, and 6 parts by mass of di-tert-butyl peroxide was used for the reaction. The reaction time was 3 hours. The solvent used for reprecipitation was 700 parts by mass of methyl ethyl ketone, and the solvent used for reslurry was 1000 parts by mass of methyl ethyl ketone. The same procedures as in Production Example 1 were carried out except that the number of times was changed to two, thereby obtaining an acid-modified polyolefin, maleic anhydride-modified propylene-1-butene copolymer A-8 (propylene component content 90 mol%, 1-butene component content 10 mol%, acid value 25 mg KOH / g, acetone extractable component ratio 1.0 mass%, storage modulus at 25°C (E') 2350 MPa, tensile break elongation at 25°C (Eb) 38%, weight average molecular weight (Mw) 60,000, melting point (Tm) 125°C, heat of fusion (ΔH) 63 J / g).

[0118] Production Example 9 A reaction mixture containing 100 parts by mass of propylene-1-butene copolymer (propylene content 78 mol%, 1-butene content 22 mol%, storage modulus at 25°C 320 MPa, tensile break elongation at 25°C 760%), 186 parts by mass of toluene, 0.5 parts by mass of maleic anhydride, and 0.1 parts by mass of di-tert-butyl peroxide was reacted for 3 hours. The reaction time was 3 hours, and the solvent used for reprecipitation was 700 parts by mass of methyl ethyl ketone. The solvent used for reslurrying was 1,000 parts by mass of methyl ethyl ketone. The same procedures as in Production Example 1 were carried out except that the polymer was changed to a maleic anhydride-modified propylene-1-butene copolymer A-9 (propylene component content 78 mol%, 1-butene component content 22 mol%, acid value 1 mgKOH / g, acetone extractable component ratio 0.1 mass%, storage modulus at 25°C (E') 290 MPa, tensile break elongation at 25°C (Eb) 700%, weight average molecular weight (Mw) 210,000, melting point (Tm) 78°C, heat of fusion (ΔH) 40 J / g), which is an acid-modified polyolefin.

[0119] Production Example 10 A mixture of 100 parts by mass of propylene-1-butene copolymer (propylene content 90 mol%, 1-butene content 10 mol%, storage modulus at 25°C 2720 MPa, tensile break elongation at 25°C 400%), 186 parts by mass of toluene, 25 parts by mass of maleic anhydride, and 9 parts by mass of di-tert-butyl peroxide was used for 5 hours. The solvent used for reprecipitation was 700 parts by mass of methyl ethyl ketone, and the solvent used for reslurry was 1000 parts by mass of methyl ethyl ketone. The same procedures as in Production Example 1 were carried out except that the number of repetitions was changed to two, thereby obtaining an acid-modified polyolefin, maleic anhydride-modified propylene-1-butene copolymer A-10 (propylene component content 90 mol%, 1-butene component content 10 mol%, acid value 25 mg KOH / g, acetone extractable component ratio 1.0 mass%, storage modulus at 25°C (E') 200 MPa, tensile break elongation at 25°C (Eb) 35%, weight average molecular weight (Mw) 9,000, melting point (Tm) 75°C, heat of fusion (ΔH) 35 J / g).

[0120] (Preparation of Main Agent 1) A 500 ml four-neck flask equipped with a water-cooled reflux condenser and a stirrer was charged with 100 parts by mass of the maleic anhydride-modified propylene-1-butene copolymer (A-1) obtained in Production Example 1, 5 parts by mass of (E-1) as the acid anhydride group-containing monomer (E), and 417 parts by mass of solvent (D1) (methylcyclohexane) and 179 parts by mass of solvent (D2) (methyl ethyl ketone) as the organic solvent (D), and the mixture was heated to 80 ° C. with stirring, and stirring was continued at 80 ° C. for 1 hour, followed by cooling to room temperature to obtain Main Agent 1. The blending amount of Main Agent 1 and the solution state of Main Agent 1 are shown in Table 1.

[0121] (Preparation of Main Agents 2 to 19) Main agents 2 to 19 were prepared in the same manner as main agent 1, except that the acid-modified polyolefin (A), organic solvent (D), and acid anhydride group-containing monomer (E) were changed as shown in Table 1. The blending amounts of main agents 2 to 19 and the solution states of main agents 2 to 19 are shown in Table 1.

[0122]

[0123] The materials used in the examples and comparative examples are as follows. <Multifunctional polyisocyanate curing agent (B)> B-1: Isocyanurate-modified hexamethylene diisocyanate, Sumidur (registered trademark) N-3300 (manufactured by Bayer) B-2: Biuret-modified hexamethylene diisocyanate, Duranate (registered trademark) 24A-100 (manufactured by Asahi Kasei Chemicals Corporation) <Organoaluminum compound (C)> C-1: Aluminum bis(ethylacetoacetate) monoacetylacetonate ("Aluminum Chelate D" manufactured by Kawaken Fine Chemicals Co., Ltd.) <Other metal organic compounds X> X-1: Organic zirconium compound (zirconium tetraacetylacetonate) ("Orgatix ZC700" manufactured by Matsumoto Fine Chemicals Co., Ltd.) X-2: Organic tin compound (dibutyltin dilaurate) (industrial reagent manufactured by Tokyo Kogyo Kasei Co., Ltd.) <Acid anhydride group-containing monomer (E)> E-1: Dodecenylsuccinic anhydride ("Rikacid DDSA" manufactured by New Japan Chemical Co., Ltd., molecular weight 266 g / mol, acid value 417 mgKOH / g)

[0124] Example 1 667 parts by mass of the main component 1, 35 parts by mass of Sumidur (registered trademark) N-3300 (B-1) as the polyfunctional polyisocyanate curing agent (B), and 0.5 parts by mass of (C-1) as the organoaluminum compound (C) were blended, and the mixture was stirred with a magnetic stirrer in an atmosphere of 25°C for 10 minutes to obtain an adhesive composition.

[0125] (Examples 2 to 22, Comparative Examples 1 to 6) Adhesive compositions were obtained in the same manner as in Example 1, except that the main components 2 to 19, the polyfunctional polyisocyanate curing agent (B), and the organoaluminum compound (C) were changed as shown in Tables 2 and 3.

[0126]

[0127]

[0128] Evaluation of Solution State The solution viscosity (mPa·s) of the solution states of main components 1 to 19 was measured at 25°C using a Brookfield viscometer TVB-10M (hereinafter sometimes referred to as a B-type viscometer) manufactured by Toki Sangyo Co., Ltd. The measured solution viscosity (mPa·s) at 25°C was evaluated according to the following evaluation criteria, and this was used as an evaluation of the solution state. The evaluation results are shown in Table 1. <Evaluation criteria> ◎ (Excellent for practical use): Less than 200 mPa·s ○ (Practical): 200 mPa·s or more but less than 1000 mPa·s × (Not practical): 1000 mPa·s or more, or viscosity measurement impossible due to gelation

[0129] Pot life evaluation refers to the composition stability of an adhesive composition. When the pot life is good, the viscosity of the composition increases little, allowing for long-term storage. When the pot life is poor, the viscosity of the composition increases. If the increase in viscosity is significant, gelation occurs, making long-term storage impossible and application to a substrate difficult. The pot life of the adhesive compositions obtained in Examples 1 to 22 and Comparative Examples 1 to 6 was evaluated based on the viscosity increase (%) shown below. Specifically, the solution viscosity at 25°C was measured using a Brookfield viscometer immediately after blending each base material, the polyfunctional polyisocyanate curing agent (B), and the organoaluminum compound (C) in the ratios shown in Tables 2 and 3, and after storing the compositions in an agitated state at 25°C for 8 hours. The viscosity increase was calculated using the following formula (1). The calculated viscosity increase was evaluated according to the following evaluation criteria, and this was used to evaluate pot life. The evaluation results are shown in Tables 2 and 3. Viscosity increase rate (%) = {(solution viscosity of adhesive composition at 25°C after stirring for 8 hours - solution viscosity of adhesive composition at 25°C immediately after blending) / solution viscosity of adhesive composition at 25°C immediately after blending} x 100 (Equation 1) <Evaluation criteria> ◎ (Excellent for practical use): Less than 50% ○ (Suitable for practical use): 50% or more but less than 200% × (Unsuitable for practical use): 200% or more or viscosity measurement impossible due to gelation

[0130] Preparation of a Laminate of a Metal Substrate and a Polyolefin Resin Substrate Aluminum foil (8079-0, 40 μm thick, manufactured by Sumikei Aluminum Foil Co., Ltd.) was used as the metal substrate, and an unstretched polypropylene film (Pylen (registered trademark) Film CT, 40 μm thick, manufactured by Toyobo Co., Ltd.) (hereinafter also referred to as CPP film) was used as the polyolefin resin substrate. The adhesive compositions obtained in Examples 1 to 22 and Comparative Examples 1 to 6 were applied to the metal substrate using a bar coater so that the adhesive layer would have a thickness of 3 μm after drying. The coated surface was dried in a hot air dryer in an atmosphere of 100°C for 1 minute to obtain a metal substrate laminated with a 3 μm thick adhesive layer. A polyolefin resin substrate was placed on the surface of the adhesive layer, and the laminate was laminated using a small desktop test laminator (SA-1010-S) manufactured by Tester Sangyo Co., Ltd. at a lamination temperature of 80°C or 120°C, a pressure of 0.3 MPa, and a speed of 1 m / min. The laminate was then aged for 96 hours at 40°C and 50% RH to obtain a laminate.

[0131] The laminate obtained as described above was evaluated for adhesiveness, heat resistance at 80° C., resistance to electrolyte, and moldability by the following methods.

[0132] Evaluation of Adhesion The laminate obtained above was cut into a size of 100 mm x 15 mm to prepare a test piece, and the adhesion of the test piece was evaluated by the following T-peel test.

[0133] <T-peel test> In accordance with the test method of ASTM-D1876-61, the peel strength (N / cm) was measured five times at a tensile speed of 50 mm / min in an environment of 25°C using a Tensilon RTM-100 manufactured by Orientec Corporation, and the average value was taken as the peel strength (N / cm) of the test piece. The peel strength (N / cm) of the obtained test piece was evaluated according to the following evaluation criteria, and this was used to evaluate the adhesion. The evaluation results are shown in Tables 2 and 3.

[0134] <Evaluation Criteria> ☆ (Excellent for practical use): 12.0 N / cm or more ◎ (Excellent for practical use): 10.0 N / cm or more and less than 12.0 N / cm ○ (Suitable for practical use): 7.0 N / cm or more and less than 10.0 N / cm × (Not suitable for practical use): Less than 7.0 N / cm

[0135] The laminate obtained above was cut into 100 mm x 15 mm pieces to prepare test pieces, and the heat resistance of the test pieces was evaluated by a T-peel test in a thermostatic chamber at 80°C. Specifically, using an AG-IS manufactured by Shimadzu Corporation equipped with a thermostatic chamber, the test pieces were placed in the thermostatic chamber heated to 80°C. After maintaining the temperature inside the chamber at 80°C for 5 minutes, the peel strength (N / cm) was measured five times at a tensile speed of 50 mm / min in an 80°C environment, and the average value was used as the peel strength (N / cm) of the test piece. The peel strength (N / cm) of the obtained test piece was evaluated according to the following evaluation criteria, and this was used to evaluate heat resistance. The evaluation results are shown in Tables 2 and 3. (Evaluation criteria) ☆ (particularly excellent for practical use): 6.0 N / cm or more ◎ (excellent for practical use): 4.5 N / cm or more and less than 6.0 N / cm ○ (practical use possible): 3.0 N / cm or more and less than 4.5 N / cm × (not practical use): less than 3.0 N / cm

[0136] Evaluation of Electrolyte Resistance To examine the usability as a packaging material for LiB, the electrolyte resistance (chemical resistance to the electrolyte) was evaluated using the peel strength (N / cm) shown below. First, the laminate obtained above was cut into 100 mm x 15 mm pieces to prepare test specimens, which were then immersed in an electrolyte solution [ethylene carbonate: diethyl carbonate: dimethyl carbonate == 1:1:1 (volume ratio) to which lithium hexafluorophosphate had been added] at 85 ° C for 7 days. The test specimens were then removed from the electrolyte solution, washed with ion-exchanged water, wiped with a paper wiper, and thoroughly dried. Next, a T-peel test was performed on the dried test specimens using the same procedure as the above <T-peel test>. The peel strength (N / cm) of the test specimens obtained was evaluated according to the following evaluation criteria, and this was used to evaluate the electrolyte resistance. The evaluation results are shown in Tables 2 and 3.

[0137] <Evaluation criteria> ☆ (particularly excellent for practical use): 8.0 N / cm or more ◎ (excellent for practical use): 6.5 N / cm or more and less than 8.0 N / cm ○ (practical use possible): 5.0 N / cm or more and less than 6.5 N / cm × (not practical use): less than 5.0 N / cm

[0138] Evaluation of formability To examine the usability as a packaging material for LiB, the formability was evaluated using a deep drawing tester. First, the laminate obtained above was cut into a size of 80 mm x 120 mm to form test pieces, which were then cold-formed. Specifically, using a deep drawing tester, a stretch forming machine (product number: TP-25C-X2) manufactured by Amada Co., Ltd., a forming mold (female mold) having a diameter of 55 mm x 35 mm, and a corresponding forming mold (male mold), cold forming was performed on 10 test pieces at each forming depth, changing the forming depth in 0.5 mm increments from a forming depth of 0.5 mm, under a pressure of 0.4 MPa in an atmosphere of 25 ° C. The test pieces after cold forming were evaluated as the limit forming depth (mm) of the test piece at which wrinkles, pinholes in the aluminum foil, cracks, etc. did not occur in all 10 test pieces. The limit forming depth (mm) of the obtained test pieces was evaluated according to the following evaluation criteria, and this was used to evaluate formability. The evaluation results are shown in Tables 2 and 3. <Evaluation criteria> ☆ (particularly excellent for practical use): limit forming depth of 6.0 mm or more ◎ (excellent for practical use): limit forming depth of 4.0 mm or more and less than 6.0 mm ○ (practical use): limit forming depth of 2.0 mm or more and less than 4.0 mm × (not practical use): limit forming depth less than 2.0 mm

[0139] [Discussion of the results in Tables 2 and 3] The adhesive compositions obtained in Examples 1 to 22 had good pot life. Furthermore, laminates of metal substrates and polyolefin resin substrates obtained using the adhesive compositions obtained in Examples 1 to 22 by laminating the substrates at a lamination temperature of 80°C or 120°C and then curing them at a low temperature of 40°C for a short period of time, such as 96 hours, had good adhesion, heat resistance, electrolyte resistance (chemical resistance to electrolyte), and formability.

[0140] On the other hand, the adhesive composition obtained in Comparative Example 1 did not contain the multifunctional polyisocyanate curing agent (B), and therefore showed extremely poor adhesion, heat resistance, and moldability. Note that the electrolyte resistance of Comparative Example 1 could not be measured because the CPP film and aluminum foil peeled off while the test piece was immersed in the electrolyte.

[0141] The adhesive composition obtained in Comparative Example 2 did not contain the organoaluminum compound (C), and therefore had extremely poor heat resistance.

[0142] In the adhesive composition obtained in Comparative Example 3, the organozirconium compound (X-1) was used instead of the organoaluminum compound (C), and as a result, the heat resistance was extremely poor.

[0143] In the adhesive composition obtained in Comparative Example 4, the organotin compound (X-2) was used instead of the organoaluminum compound (C), and as a result, the pot life was extremely poor.

[0144] In the adhesive composition obtained in Comparative Example 5, the base agent 18 was prepared using A-9, which had a large weight average molecular weight of 210,000, and as a result, the heat resistance and electrolyte resistance were extremely poor.

[0145] In the adhesive composition obtained in Comparative Example 6, the base agent 19 was prepared using A-10, which had a small weight average molecular weight of 9,000, and as a result, the heat resistance and moldability were extremely poor.

[0146] The adhesive composition of this embodiment is excellent in pot life, adhesion, heat resistance, chemical resistance to electrolytes, and moldability. Therefore, laminates of polyolefin resin substrates and metal substrates formed from the adhesive composition of this embodiment can be widely used not only in fields such as outer panels of home appliances, furniture materials, and building interior components, but also as packaging materials (in the form of pouches) for lithium batteries used in personal computers, mobile phones, video cameras, etc.

Claims

1. An adhesive composition comprising an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B) and an organoaluminum compound (C), wherein the weight average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000.

2. The adhesive composition according to claim 1, wherein the content of the multifunctional polyisocyanate curing agent (B) is 0.5 to 70 parts by mass per 100 parts by mass of the acid-modified polyolefin (A).

3. The adhesive composition according to claim 1, wherein the content of the organoaluminum compound (C) is 0.01 to 2 parts by mass per 100 parts by mass of the acid-modified polyolefin (A).

4. The adhesive composition according to claim 1, wherein the acid-modified polyolefin (A) is a graft polymer having a structure in which at least one member selected from the group consisting of α,β-unsaturated carboxylic acids and acid anhydrides thereof is grafted to a polyolefin.

5. The adhesive composition according to claim 1, wherein the acid-modified polyolefin (A) has an acid value of 2 to 50 mgKOH / g.

6. The adhesive composition according to claim 1, wherein the organoaluminum compound (C) is an aluminum alcoholate compound and / or an aluminum chelate compound.

7. The adhesive composition according to claim 1, further comprising an organic solvent (D).

8. The adhesive composition according to claim 7, wherein the organic solvent (D) comprises a solvent (D1) and a solvent (D2), the solvent (D1) is at least one solvent selected from the group consisting of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and halogenated hydrocarbon solvents, and the solvent (D2) is at least one solvent selected from the group consisting of alcohol solvents, ketone solvents, ester solvents, and glycol ether solvents.

9. The adhesive composition according to claim 8, wherein the mass ratio of the solvent (D1) to the solvent (D2) (solvent (D1) / solvent (D2)) is 50 / 50 to 97 / 3.

10. The adhesive composition according to claim 1, further comprising an acid anhydride group-containing monomer (E).

11. The adhesive composition according to claim 10, wherein the content of the acid anhydride group-containing monomer (E) is 0.1 to 20 parts by mass per 100 parts by mass of the acid-modified polyolefin (A).

12. The adhesive composition according to claim 10, wherein the acid anhydride group-containing monomer (E) contains a hydrocarbon group having 3 to 20 carbon atoms.

13. The adhesive composition according to any one of claims 1 to 12, which is used for bonding a polyolefin resin substrate to a metal substrate.

14. A laminate comprising a polyolefin resin substrate and a metal substrate bonded together with the adhesive composition according to any one of claims 1 to 12.

15. A packaging material for a lithium ion battery comprising the laminate of claim 14.