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

Abstract

Provided is a binder composition having good pot life performance, adhesiveness, heat resistance, chemical resistance to an electrolyte solution, and moldability. Specifically, the present invention provides an adhesive composition containing an acid-modified polyolefin (A) having a weight average molecular weight (Mw) in the range of 10,000-200,000, a polyfunctional polyisocyanate curing agent (B), and an organoaluminum compound (C).

Description

Technical Field

[0001] This invention relates to polyolefin adhesive compositions, laminates, and packaging materials for lithium-ion batteries. Background Technology

[0002] In recent years, lithium-ion batteries (hereinafter referred to as "LiB"), which can be made ultra-thin and miniaturized, are being widely developed for use in personal computers, mobile phones and other mobile terminal devices, cameras, satellites, etc. Unlike the metal cans that were previously widely known, LiB packaging materials have begun to use multi-layered laminates consisting of a substrate layer, a barrier layer, and a sealing layer, due to their advantages of being lightweight and allowing for free selection of battery shape.

[0003] As a component of the battery, besides the positive and negative electrode materials, LiB also includes an electrolyte layer composed of an electrolyte solution containing lithium salts dissolved in a non-protic solvents such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate, or a polymer gel impregnated with such an electrolyte. It is known that when such highly permeable electrolytes pass through the sealing layer, they reduce the lamination strength between the barrier layer and the sealing layer, causing delamination and ultimately leading to electrolyte leakage. Furthermore, while lithium salts such as LiPF6 and LiBF4 are used as electrolytes in batteries, these salts produce hydrofluoric acid through hydrolysis with water. Hydrofluoric acid corrodes the barrier layer, reducing lamination strength. Therefore, adhesives for LiB need to possess durability against both the electrolyte and the electrolyte solution. In addition, adhesives for LiB are required to exhibit adhesive properties when bonded at temperatures below 120°C.

[0004] Furthermore, considering the use of LiB in various environments, durability is required. For example, when LiB is used in mobile devices, leak-proof performance is required in environments around 80°C. In automotive applications, considering the use in environments with higher temperatures than typical small LiB applications, LiB adhesives are required to have heat resistance of around 80°C.

[0005] In this context, an adhesive for lithium-ion batteries has been proposed with the aim of improving heat resistance and chemical resistance to electrolytes, 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 the chemical resistance to electrolytes in the long term, battery packaging materials containing acid-modified polyolefins, polyfunctional isocyanate curing agents and organometallic catalysts such as tin, titanium, and zirconium have been proposed (e.g., Patent Document 2).

[0007] Existing technical documents

[0008] Patent documents

[0009] [Patent Document 1] International Publication No. 2021 / 106849

[0010] [Patent Document 2] Japanese Patent Application Publication No. 2018-49849 Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, in Patent Document 1, a long curing time of 5 days at 40°C is required to fully promote the curing reaction.

[0013] In the lithium battery outer packaging material containing an organometallic catalyst described in Patent Document 2, although the organotin compound promotes the curing reaction due to its catalytic function, it also causes significant thickening and gelation due to prolonged stirring, thus failing to fully meet the pot life requirement. Furthermore, the lithium battery outer packaging material described in Patent Document 2 exhibits poor heat resistance and chemical resistance to the electrolyte.

[0014] Furthermore, in recent years, organotin compounds have been found to be toxic, particularly tributyltin (TBT) in dibutyltin compounds, which has raised concerns as an endocrine disruptor, leading to restrictions on its use. Additionally, for organotitanium and organozirconium compounds, the curing reaction is not sufficiently promoted under short curing times.

[0015] In view of the above, the present invention aims to provide an adhesive composition with good pot life performance, adhesion, heat resistance, chemical resistance to electrolytes and formability.

[0016] Methods for solving problems

[0017] In order to achieve the above objectives, the inventors conducted in-depth research and found that the above objectives could be achieved by using acid-modified polyolefins, polyfunctional polyisocyanate curing agents and organoaluminum compounds containing a specific range of weight-average molecular weights, and thus completed the present invention.

[0018] This invention, for example, includes the subject matter described in the following items.

[0019] Item 1.

[0020] An adhesive composition comprising an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organoaluminum compound (C).

[0021] The weight-average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000.

[0022] Invention Effects

[0023] The adhesive composition of the present invention exhibits excellent pot life performance, adhesion, heat resistance, chemical resistance to electrolytes, and formability. Due to these properties, the adhesive composition of the present invention is preferably used as a packaging material for lithium-ion batteries. Detailed Implementation

[0024] Hereinafter, preferred embodiments of the present invention will be described in detail. The description of the configuration conditions described below is sometimes based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

[0025] In this specification, expressions consisting of "containing" and "including" include the concepts of "containing", "including", "substantially constituted by", and "consisting solely of".

[0026] In this specification, the upper or lower limit of the numerical range described in stages can be arbitrarily combined with the upper or lower limits of the numerical ranges in other stages. Furthermore, the upper or lower limit of the numerical range described in this specification can also be replaced with the values ​​shown in the embodiments or values ​​explicitly derived from the embodiments. Further, in this specification, numerical values ​​connected by "~" represent a numerical range including the values ​​before and after "~" as both the lower and upper limits.

[0027] In this specification, "A and / or B" means "one of A and B" or "both of A and B", specifically, "A", "B" or "A and B".

[0028] In this manual, "n-" means "positive", "iso-" means "different", "sec-" means "secondary", and "tert-" or "t-" means "uncle".

[0029] In this instruction manual, room temperature refers to a temperature within the range of 20℃ to 25℃.

[0030] 1. Adhesive composition

[0031] The adhesive composition of this embodiment has the following components (I) and (II):

[0032] (I) Contains acid-modified polyolefin (A), polyfunctional polyisocyanate curing agent (B) and organoaluminum compound (C).

[0033] (II) The weight-average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000.

[0034] Since the adhesive composition of this embodiment has the above-described components (I) and (II), it has good pot life performance, adhesion, heat resistance, chemical resistance to electrolyte, and formability.

[0035] <Acid-modified polyolefin (A)>

[0036] This invention contains an acid-modified polyolefin (A) as an essential component. As one embodiment, the acid-modified polyolefin (A) is preferably a polymer obtained by grafting a polyolefin with at least one of α,β-unsaturated carboxylic acids and their anhydrides. In other words, as one embodiment, the acid-modified polyolefin (A) is preferably a grafted polymer having a structure of at least one α,β-unsaturated carboxylic acid and its anhydride grafted onto a polyolefin.

[0037] Examples of polyolefins include homopolymer polyethylene (a homopolymer of ethylene), homopolymer polypropylene (a homopolymer of propylene), and propylene-α-olefin copolymers. These polyolefins can be used individually or in combination of two or more. As one embodiment, homopolymer polypropylene and / or propylene-α-olefin copolymers are preferred among these polyolefins.

[0038] As one embodiment, the acid-modified polyolefin (A) is more preferably a grafted polymer having a structure of homopolymer polypropylene or propylene-α-olefin copolymer grafted with α,β-unsaturated carboxylic acid or its anhydride.

[0039] A propylene-α-olefin copolymer is a substance in which propylene is used as the main component and copolymerized with α-olefins. 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 individually or in combination of two or more. As one embodiment, the α-olefin in the propylene-α-olefin copolymer is preferably ethylene and / or 1-butene, more preferably 1-butene.

[0040] As one embodiment, the propylene content 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 propylene content in the propylene-α-olefin copolymer is 50 mol% or more, the adhesive composition exhibits even better adhesion strength to the polyolefin substrate (especially the polypropylene substrate).

[0041] Examples of α,β-unsaturated carboxylic acids and / or their anhydrides that can be grafted onto polyolefins include, for example, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citric acid, citraconic acid, citraconic anhydride, aconitic acid, and aconitic anhydride. Among these, anhydrides of α,β-unsaturated carboxylic acids are preferred, and maleic anhydride is more preferred.

[0042] Specifically, examples of acid-modified polyolefins (A) include maleic anhydride-modified homopolymer polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-1-butene copolymer, and maleic anhydride-modified propylene-ethylene-1-butene copolymer. One or more of these acid-modified polyolefins can be used in combination. As one embodiment, the acid-modified polyolefin (A) is preferably maleic anhydride-modified homopolymer polypropylene and / or maleic anhydride-modified propylene-1-butene copolymer, more preferably maleic anhydride-modified homopolymer polypropylene or maleic anhydride-modified propylene-1-butene copolymer.

[0043] As a method for grafting polyolefins with α,β-unsaturated carboxylic acids or their anhydrides, well-known methods can be widely employed. Examples of such methods include, for instance, heating the polyolefin above its melting point in the presence of a free radical initiator to melt it and reacting it with α,β-unsaturated carboxylic acids or their anhydrides (melt method); and dissolving the polyolefin in an organic solvent and then heating and stirring it in the presence of a free radical initiator to react it with α,β-unsaturated carboxylic acids or their anhydrides (solution method), etc.

[0044] Organic peroxides are preferably used as free radical initiators. Examples of organic peroxides include di-tert-butyl peroxide phthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxide, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxypentanoate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauroyl peroxide, etc.; and azo nitrile compounds such as azobisisobutyronitrile and azobisisopropionitrile, etc.

[0045] The acid-modified polyolefin (A) is preferably unchlorinated. Specifically, the chlorine content is preferably 3% by mass or less, more preferably 2% by mass or less, further preferably 1% by mass or less, and most preferably 0% by mass. When the chlorine content is 3% by mass or less, the environmental impact can be reduced. Furthermore, even when the adhesive composition of the present invention is used in packaging materials for lithium-ion batteries, it can prevent the emission of chlorine and hydrogen chloride, thus inhibiting battery corrosion.

[0046] As one embodiment, the content of 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.

[0047] As one embodiment, the acid value of the acid-modified polyolefin (A) is preferably 2-50 mg KOH / g, more preferably 3-45 mg KOH / g, even more preferably 5-40 mg KOH / g, and particularly preferably 7-35 mg KOH / g. When the acid value of the acid-modified polyolefin (A) is 2-50 mg KOH / g, the compatibility between the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) becomes better, and it tends to have a good crosslinking density. As a result, the adhesion, heat resistance, and chemical resistance to electrolytes tend to be more excellent.

[0048] The acid value of acid-modified polyolefin (A) can be adjusted by the amount of α,β-unsaturated carboxylic acid, the anhydride of α,β-unsaturated carboxylic acid, and the amount of free radical initiator used.

[0049] As one embodiment, the acetone-extractable component ratio in the acid-modified polyolefin (A) is preferably 0.01% to 2% by mass, more preferably 0.03% to 1.7% by mass, even more preferably 0.05% to 1.4% by mass, even more preferably 0.07% to 1.2% by mass, and particularly preferably 0.1% 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 manufacturing efficiency of the adhesive composition is further improved, the adhesive composition exhibits better cohesiveness, and the adhesion, chemical resistance to electrolyte, and formability tend to be more superior. The acetone-extractable component ratio in the acid-modified polyolefin (A) is measured using a Soxhlet extractor after reflux with acetone for 2 hours. Specific measurement methods are described in the examples described later.

[0050] The acetone-extractable component ratio of acid-modified polyolefin (A) can be adjusted by reprecipitating with methyl ethyl ketone to purify unreacted monomers, low molecular weight components, etc. Examples of such low molecular weight components include low molecular weight polyolefins with a weight-average molecular weight (Mw) of 100 to 10,000.

[0051] As one embodiment, to further improve adhesion and chemical resistance to electrolytes, the storage modulus (E') of the acid-modified polyolefin (A) at 25°C is preferably 10-2500 MPa, more preferably 15-2000 MPa, further preferably 20-1500 MPa, particularly preferably 25-1100 MPa, and most preferably 30-800 MPa. When the storage modulus (E') of the acid-modified polyolefin (A) at 25°C is 10-2500 MPa, the adhesion and substrate conformability of the adhesive composition are further improved, and the formability of the laminate becomes better. The storage modulus (E') of the acid-modified polyolefin (A) at 25°C can be determined according to the test method of JIS K7244-4 (1999). Specific determination methods are described in the examples described later.

[0052] As one embodiment, the elongation at break (Eb) of the acid-modified polyolefin (A) at 25°C is preferably 50% to 1000%, more preferably 80% to 900%, further preferably 120% to 800%, particularly preferably 160% to 700%, and most preferably 200% to 600%. When the elongation at break (Eb) of the acid-modified polyolefin (A) at 25°C is 50% to 1000%, the adhesiveness and substrate conformability of the adhesive composition are further improved, and the formability of the laminate becomes better. The elongation at break (Eb) of the acid-modified polyolefin (A) at 25°C can be determined according to the test method of JIS K7161 (2014). Specific measurement methods are described in the examples described later.

[0053] The weight-average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000. Preferably, the Mw of the acid-modified polyolefin (A) is 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. When the Mw of the acid-modified polyolefin (A) is less than 10,000, the cohesive force of the acid-modified polyolefin (A) weakens, and the adhesive composition exhibits poor adhesion. When the Mw of the acid-modified polyolefin (A) is greater than 200,000, the flowability of the acid-modified polyolefin (A) decreases, the pot life performance of the adhesive composition deteriorates, and operational problems arise during bonding. Because the weight-average molecular weight (Mw) of acid-modified polyolefin (A) is in the range of 10,000 to 200,000, it exhibits good cohesive strength and flowability, thus resulting in good pot life performance, heat resistance, and chemical resistance to electrolytes in the adhesive composition. The weight-average molecular weight (Mw) of acid-modified polyolefin (A) can be determined by gel permeation chromatography (GPC). Specific determination methods are described in the examples described later.

[0054] As one embodiment, the acid-modified polyolefin (A) is preferably crystalline. In this specification, crystallinity means that, when heated from -100°C to 250°C at a rate of 20°C / min using a differential scanning calorimeter (DSC), a distinct melting peak is observed during this heating process. When the acid-modified polyolefin (A) is crystalline, its cohesive strength is further enhanced, thus further improving the adhesive properties, heat resistance, and chemical resistance to electrolytes in the adhesive composition.

[0055] As 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 determined 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, thus further improving the pot life performance, adhesion, heat resistance, and chemical resistance to electrolytes of the adhesive composition.

[0056] As 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 of the acid-modified polyolefin (A) due to crystallization is further improved, thus further improving the pot life performance, adhesion, heat resistance and chemical resistance to electrolyte of the adhesive composition.

[0057] <Multifunctional Polyisocyanate Curing Agent (B)>

[0058] This invention contains a polyfunctional polyisocyanate curing agent (B) as an essential component. The polyfunctional polyisocyanate curing agent (B) is typically a polyisocyanate compound having two or more isocyanate groups per molecule.

[0059] As one embodiment, in order to further improve the heat resistance and chemical resistance of the adhesive composition to the electrolyte, the multifunctional polyisocyanate curing agent (B) is preferably a diisocyanate compound and its derivatives, more preferably a derivative of a diisocyanate compound.

[0060] Examples of the aforementioned diisocyanate compounds include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, phenylenediamine diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, bis(4-isocyanatecyclohexyl)methane, and hydrogenated diphenylmethane diisocyanate. These diisocyanate compounds can be used individually or in combination of two or more. Among the aforementioned diisocyanate compounds, hexamethylene diisocyanate is particularly preferred.

[0061] Examples of derivatives of the aforementioned diisocyanate compounds include isocyanurate-modified forms of diisocyanate compounds, adduct-modified forms of diisocyanate compounds, biuret-modified forms of diisocyanate compounds, urea-dione-modified forms of diisocyanate compounds, urea-formate-modified forms of diisocyanate compounds, and prepolymers having isocyanate residues (oligopolymers (molecular weight 300 g / mol to 4,000 g / mol) obtained from diisocyanate compounds and polyol compounds). These derivatives of diisocyanate compounds can be used individually or in combination of two or more.

[0062] As one embodiment, to further improve the heat resistance and chemical resistance of the adhesive composition to the electrolyte, the derivative of the diisocyanate compound is preferably at least one selected from the group consisting of isocyanurate modified form of hexamethylene diisocyanate, adduct modified form of hexamethylene diisocyanate, biuret modified form of hexamethylene diisocyanate, urea diketone modified form of hexamethylene diisocyanate, and urethane modified form of hexamethylene diisocyanate.

[0063] As one embodiment, to further improve the heat resistance and chemical resistance of the adhesive composition to the electrolyte, the multifunctional polyisocyanate curing agent (B) is preferably an isocyanurate modified form of a diisocyanate compound and / or a biuret modified form of a diisocyanate compound, more preferably at least one selected from the group consisting of an isocyanurate modified form of hexamethylene diisocyanate, an adduct modified form of hexamethylene diisocyanate, a biuret modified form of hexamethylene diisocyanate, a urea diketone modified form of hexamethylene diisocyanate, and a urea carbamate modified form of hexamethylene diisocyanate, particularly preferably an isocyanurate modified form of hexamethylene diisocyanate and / or a biuret modified form of hexamethylene diisocyanate.

[0064] In addition, the product obtained by reacting a portion of the isocyanate groups in the above-mentioned isocyanate compounds with compounds that have isocyanate group reactivity can also be used as a multifunctional polyisocyanate curing agent. Examples of compounds that have isocyanate group reactivity include, for example, compounds containing amino groups such as butylamine, hexylamine, octylamine, 2-ethylhexylamine, dibutylamine, ethylenediamine, benzylamine, and aniline; compounds containing hydroxyl groups such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, octanol, 2-ethylhexanol, dodecyl alcohol, ethylene glycol, propylene glycol, benzyl alcohol, and phenol; compounds containing epoxy groups such as allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and cyclohexanediethanol diglycidyl ether; and compounds containing carboxyl groups such as acetic acid, butyric acid, hexanoic acid, octanoic acid, succinic acid, adipic acid, sebacic acid, and phthalic acid.

[0065] As one embodiment, the content of the multifunctional polyisocyanate curing agent (B) relative to 100 parts by weight of the acid-modified polyolefin (A) is preferably 0.5 to 70 parts by weight, more preferably 1 to 65 parts by weight, even more preferably 2 to 60 parts by weight, further preferably 3 to 55 parts by weight, even more preferably 6 to 50 parts by weight, particularly preferably 10 to 45 parts by weight, and most preferably 15 to 40 parts by weight. When the content of the multifunctional polyisocyanate curing agent (B) relative to 100 parts by weight of the acid-modified polyolefin (A) is 0.5 to 70 parts by weight, the adhesive composition cures better, the adhesive composition has better substrate conformability, and the adhesion, heat resistance, chemical resistance to electrolyte, and formability are all better.

[0066] <Organoaluminum compounds>

[0067] This invention contains an organoaluminum compound (C) as an essential component. Due to the presence of organoaluminum compound (C), the curing reaction of the adhesive composition can be promoted within a shorter curing period, thus enabling the adhesive composition to cure well through a post-bonding curing process. Furthermore, the presence of organoaluminum compound (C) improves the pot life, heat resistance, and chemical resistance to electrolytes of the adhesive composition.

[0068] As one embodiment, the organoaluminum compound (C) is preferably an aluminum alkoxide compound and / or an aluminum chelate, more preferably an aluminum chelate.

[0069] Examples of aluminum alkoxide compounds include aluminum ethoxide, aluminum isopropoxide, aluminum diisopropoxy monosec-butoxide, and aluminum sec-butoxide, which can be used individually or in combination of two or more.

[0070] Aluminum chelates are typically compounds in which a central aluminum atom is bonded to one or more polydentate ligands L. Aluminum chelates may or may not have one or more monodentate ligands X bonded to the aluminum atom.

[0071] For example, when the general formula of an aluminum chelate with one aluminum atom is represented by Al(L)m(X)n, m is an integer greater than or equal to 1, and n is an integer greater than or equal to 0. When m is 2 or more, the m L atoms can be the same ligand or different ligands. When n is 2 or more, the n X atoms can be the same ligand or different ligands.

[0072] Examples of polydentate ligands L include β-keto esters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate, as well as keto-enol tautomers such as acetylacetone (2,4-pentanedione), 2,4-hexanedione, and benzoylacetone. Keto-enol tautomers refer to compounds capable of forming keto-enol tautomers. Among polydentate ligands L, these keto-enol tautomers can also be enol salts after deprotonation of the enol (e.g., acetylacetone salts).

[0073] As a monodentate ligand X, examples include halogen atoms such as chlorine and bromine; acyloxy groups such as valeryl, hexanoyl, 2-ethylhexanoyl, octanoyl, nonanoyl, decanoyl, dodecanoyl, octadecanoyl, etc.; and alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, butoxy, etc.

[0074] As one embodiment, from the viewpoint of further promoting the curing reaction of the adhesive composition and the adhesive composition having better pot life performance, heat resistance and chemical resistance to electrolyte, the organoaluminum compound (C) is preferably an aluminum chelate having ketone-enol tautomer coordination.

[0075] Examples of aluminum chelates include aluminum diisopropyl acetoacetate, ethyl aluminum diisopropyl acetoacetate, tris(ethylacetoacetyl)aluminum, alkylacetate aluminum diisopropyl ester, bis(ethylacetoacetyl)monoacetylacetonate aluminum, and tris(acetylacetonate)aluminum, which can be used alone or in combination of two or more.

[0076] As one embodiment, the content of the organoaluminum compound (C) relative to 100 parts by weight of the acid-modified polyolefin (A) is preferably 0.01 to 2 parts by weight, more preferably 0.05 to 1.5 parts by weight, even more preferably 0.1 to 1.25 parts by weight, even more preferably 0.2 to 1.0 parts by weight, and particularly preferably 0.3 to 0.95 parts by weight. When the content of the organoaluminum compound (C) relative to 100 parts by weight of the acid-modified polyolefin (A) is 0.01 to 2 parts by weight, the curing reaction of the adhesive composition is further promoted, and the pot life performance, heat resistance, and chemical resistance to electrolyte of the adhesive composition are further improved.

[0077] As one embodiment, the content of the organoaluminum compound (C) relative to 100 parts by weight of the polyfunctional polyisocyanate curing agent (B) is preferably 0.05 to 30 parts by weight, more preferably 0.25 to 20 parts by weight, even more preferably 0.5 to 16 parts by weight, even more preferably 0.9 to 12 parts by weight, even more preferably 1.0 to 10 parts by weight, particularly preferably 1.1 to 8 parts by weight, and most preferably 1.2 to 6 parts by weight.

[0078] <Organic Solvents (D)>

[0079] The adhesive composition of this embodiment may further contain an organic solvent (D). Examples of organic solvents (D) include, for example, 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, isopropanol, butanol, pentanol, hexanol, propylene glycol, and phenol; and acetone, methyl isobutyl ketone, methyl ethyl ketone, pentanol, hexanol, and cyclohexanol. Ketone solvents such as hexanone, isophorone, and acetophenone; cellosol solvents such as methyl cellosol and ethyl cellosol; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl propionate, and butyl formate; and glycol ether solvents such as ethylene glycol mono-n-butyl ether, ethylene glycol mono-isobutyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-isobutyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether, can be used individually or in combination of two or more.

[0080] As one embodiment, the content of organic solvent (D) relative to 100 parts by weight of acid-modified polyolefin (A) is preferably 80 to 2000 parts by weight, more preferably 100 to 1600 parts by weight, even more preferably 150 to 1200 parts by weight, even more preferably 200 to 1000 parts by weight, even more preferably 300 to 950 parts by weight, particularly preferably 400 to 900 parts by weight, and most preferably 425 to 800 parts by weight. When the content of organic solvent (D) relative to 100 parts by weight of acid-modified polyolefin (A) is 80 to 2000 parts by weight, the solution state of the main agent and the pot life performance of the adhesive composition become better.

[0081] As one embodiment, for further improving the solution state of the main agent and the pot life performance of the adhesive composition, preferably, the organic solvent (D) is composed of solvent (D1) and solvent (D2), wherein solvent (D1) is 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 solvent (D2) is at least one solvent (D2) selected from the group consisting of alcohol solvents, ketone solvents, ester solvents and glycol ether solvents.

[0082] As one embodiment, more preferably, for the purpose of further improving the solution state of the main agent and the pot life performance of the adhesive composition, the organic solvent (D) is composed 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.

[0083] As one embodiment, for the purpose of further improving the solution state of the main agent and the pot life performance of the adhesive composition, it is particularly preferred that the organic solvent (D) is composed of solvent (D1) and solvent (D2), wherein solvent (D1) is an alicyclic hydrocarbon solvent and solvent (D2) is a ketone solvent.

[0084] As one embodiment, in order to further improve the solution state of the main agent and the pot life performance of the adhesive composition, the mass ratio of solvent (D1) to solvent (D2) (solvent (D1) / solvent (D2)) is 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.

[0085] <Monomers containing anhydride groups (E)>

[0086] The adhesive composition of this embodiment may further contain a monomer (E) containing an anhydride group. Due to the presence of a monomer (E) containing an anhydride group, the heat resistance is further improved.

[0087] As one embodiment, the molecular weight of the anhydride-containing monomer (E) is preferably 100 g / mol or more and 500 g / mol or less. More preferably, the molecular weight of the anhydride-containing monomer (E) is 150 g / mol or more, and even more preferably 200 g / mol or more. Furthermore, the molecular weight of the anhydride-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 anhydride-containing monomer (E) is 500 g / mol or less, the compatibility between the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) becomes better, and the adhesiveness of the adhesive composition is further improved. Furthermore, when the molecular weight of the anhydride-containing monomer (E) is 100 g / mol or more, the anhydride-containing monomer (E) is less prone to exudation, and the adhesiveness and heat resistance of the adhesive composition tend to become even better.

[0088] As one embodiment, the acid value of the monomer (E) containing anhydride groups is preferably 150 mg KOH / g or more and 800 mg KOH / g or less. More preferably, the acid value of the monomer (E) containing anhydride groups is 250 mg KOH / g or more, and even more preferably 300 mg KOH / g or more. Furthermore, the acid value of the monomer (E) containing anhydride groups is more preferably 600 mg KOH / g or less, and even more preferably 500 mg KOH / g or less. When the acid value of the monomer (E) containing anhydride groups is 800 mg KOH / g or less, the monomer (E) containing anhydride groups is less likely to ooze out before the adhesive composition cures, and the adhesive properties and heat resistance of the adhesive composition tend to improve further. Furthermore, when the acid value of the monomer (E) containing anhydride groups is 150 mg KOH / g or more, the chemical resistance of the adhesive composition to the electrolyte becomes even better.

[0089] The monomer (E) containing an anhydride group typically has one or more anhydride groups per molecule, preferably one anhydride group per molecule. As one embodiment, the anhydride group contained in the monomer (E) is preferably an anhydride group with 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, a group derived from an anhydride generally refers to a monovalent group having a structure in which one hydrogen atom (the hydrogen atom present in a hydrocarbon group) is removed from the anhydride; for example, a group derived from succinic anhydride represents a monovalent group having a structure in which one hydrogen atom is removed from succinic anhydride.

[0090] Examples of monomers (E) containing an anhydride group include, for example, succinic anhydride, maleic anhydride, glutaric anhydride, butyl succinic anhydride, hexyl succinic anhydride, octyl succinic anhydride, dodecyl succinic anhydride, dodecenyl succinic anhydride, tetrapropylene succinic anhydride, butyl maleic anhydride, pentyl maleic anhydride, hexyl maleic anhydride, octyl maleic anhydride, decyl maleic anhydride, dodecyl maleic anhydride, butyl glutamic anhydride, hexyl glutamic anhydride, heptyl glutamic anhydride, octyl glutamic anhydride, decyl glutamic anhydride, and dodecyl glutamic anhydride. Compounds containing anhydride groups, such as anhydrides with alkyl chains and anhydride groups; monomers containing anhydride groups, such as pyromellitic anhydride, trimellitic anhydride, benzophenone tetracarboxylic dianhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltrihydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexene dianhydride, hysteretic anhydride, and tetrabromophthalic anhydride, which have alicyclic or aromatic ring structures and anhydride groups, etc., can be used alone or in combination of two or more. From a processability point of view, dodecenylsuccinic anhydride is particularly preferred. Dodecenylsuccinic anhydride is usually liquid at room temperature.

[0091] As one embodiment, the monomer (E) containing an anhydride group preferably has a hydrocarbon group, more preferably the hydrocarbon group is bonded to the anhydride group. Furthermore, the hydrocarbon group is more preferably linear. When the monomer (E) containing an anhydride group contains a hydrocarbon group, the compatibility between the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) is improved, and the pot life performance, adhesion, heat resistance, and chemical resistance to electrolytes of the adhesive composition are particularly easily improved.

[0092] When the monomer (E) containing an anhydride group has a hydrocarbon group, the number of carbon atoms in the hydrocarbon group is preferably 3 or more and 20 or less (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 number of carbon atoms in the hydrocarbon group is 3 or more but less than 20, the compatibility with acid-modified polyolefin (A) and polyfunctional polyisocyanate curing agent (B) is further improved, and the pot life performance, adhesion and chemical resistance to electrolyte of the adhesive composition become even better.

[0093] As one embodiment, the monomer (E) containing an anhydride group preferably has a straight-chain alkyl group with 3 or more but less than 20 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20), more preferably has a straight-chain alkyl group with 5 or more but less than 18 carbon atoms (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18), even more preferably has a straight-chain alkyl group with 8 or more but less than 16 carbon atoms (8, 9, 10, 11, 12, 13, 14, 15 or 16), and particularly preferably has a straight-chain alkyl group with 11 or more but less than 15 carbon atoms (11, 12, 13, 14 or 15).

[0094] As one embodiment, the content of the anhydride-containing monomer (E) is preferably 0.1 parts by mass or more relative to 100 parts by mass of the acid-modified polyolefin (A). When the content of the anhydride-containing monomer (E) is 0.1 parts by mass or more relative to 100 parts by mass of the acid-modified polyolefin (A), the heat resistance and chemical resistance to the electrolyte of the adhesive composition are further improved due to the synergistic effect of the polyfunctional polyisocyanate curing agent (B) and the anhydride-containing monomer (E). The content of the anhydride-containing monomer (E) is more preferably 0.3 parts by mass or more relative to 100 parts by mass of the acid-modified polyolefin (A), more preferably 0.5 parts by mass or more, and particularly preferably 1 part by mass or more.

[0095] As one embodiment, the content of the anhydride-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 anhydride-containing monomer (E) is 20 parts by mass or less relative to 100 parts by mass of the acid-modified polyolefin (A), the heat resistance, adhesion, and chemical resistance to the electrolyte of the adhesive composition become good, and in particular, it tends to exhibit excellent long-term chemical resistance to the electrolyte. More preferably, it is 10 parts by mass or less, further preferably 8 parts by mass or less, and particularly preferably 5 parts by mass or less.

[0096] As one embodiment, in order to further improve the adhesiveness, heat resistance and chemical resistance to electrolyte of the adhesive composition, the content of the anhydride-containing monomer (E) is preferably 0.1 parts by mass or more and 20 parts by mass or less relative to 100 parts by mass of the acid-modified polyolefin (A), 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 1 part by mass or 5 parts by mass or less.

[0097] The adhesive composition of this embodiment contains an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organoaluminum compound (C) as essential components. When the adhesive composition of this embodiment contains an organic solvent (D), the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B) can be dissolved or dispersed in the organic solvent (D), and preferably dissolved in the organic solvent (D) for further improving pot life performance.

[0098] Without impairing the performance of the present invention, in addition to acid-modified polyolefin (A), polyfunctional polyisocyanate curing agent (B), and organoaluminum compound (C), the adhesive composition of this embodiment may also contain various adhesive additives, thermoplastic elastomers, and plasticizers. These may be used individually or in combination of two or more.

[0099] As an adhesive agent, there are no particular limitations. Examples include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymer petroleum resins, and hydrogenated petroleum resins. These can be used individually or in combination of two or more.

[0100] As thermoplastic elastomers, examples include styrene-based elastomers such as styrene-ethylene-butene-styrene copolymer resin and styrene-ethylene-propylene-styrene copolymer resin; olefin-based elastomers such as ethylene-propylene copolymer resin, ethylene-butene copolymer resin, ethylene-vinyl acetate copolymer resin, and ethylene-ethyl acrylate copolymer resin. These can be used individually or in combination of two or more.

[0101] As plasticizers, examples include liquid rubbers such as polyisoprene and polybutene; processing oils, etc., which can be used individually or in combination of two or more.

[0102] Within the scope of not impairing the performance of the present invention, the adhesive composition of this embodiment may incorporate both a polyfunctional polyisocyanate curing agent (B) and various curing agents other than the polyfunctional polyisocyanate curing agent (B). Examples of curing agents other than the polyfunctional polyisocyanate curing agent (B) include, for example, curing agents having functional groups that react with acid-modified polyolefins (A). Examples of curing agents other than the polyfunctional polyisocyanate curing agent (B) include, for example, epoxy resins, carbodiimide compounds, oxazoline compounds, coupling agents, etc.

[0103] Examples of epoxy resins include glycidyl hexahydrophthalic acid glycidyl ester type, such as dimeric glycidyl ester; alicyclic or aliphatic epoxides such as triglycidyl isocyanurate, 3,4-epoxycyclohexyl methyl methacrylate, epoxidized polybutadiene, and epoxidized soybean oil; glycidyl ether type epoxy resin, glycidyl amine type epoxy resin, etc.

[0104] Examples of carbodiimide compounds include, for instance, monocarbodiimide compounds such as dimethylcarbodiimide, diisopropylcarbodiimide, dicyclohexylcarbodiimide, tert-butylisopropylcarbodiimide, diphenylcarbodiimide, and di-β-naphthylcarbodiimide; and polycarbodiimide compounds obtained by decarboxylation condensation reactions of organic diisocyanates such as aliphatic diisocyanates, aromatic diisocyanates, and alicyclic diisocyanates in the presence of a condensation catalyst in a solvent-free or inert solvent.

[0105] Examples of oxazoline compounds include, for example, monooxazoline compounds such as 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, or 2,4-diphenyl-2-oxazoline; and bisoxazoline 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), or 2,2'-(1,4-phenylene)-bis(2-oxazoline).

[0106] Examples of coupling agents include silane coupling agents and titanate coupling agents.

[0107] Without impairing the performance of the present invention, in addition to acid-modified polyolefin (A), polyfunctional polyisocyanate curing agent (B), and organoaluminum compound (C), the adhesive composition of this embodiment may also contain ketone-enol tautomer compounds.

[0108] Examples of β-keto esters that are keto-enol tautomers include methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate; as well as β-diketones such as acetylacetone, 2,4-hexanedione, and benzoylacetone. These compounds can protect the isocyanate groups of the multifunctional polyisocyanate curing agent (B), inhibit significant viscosity increases and gelation of the adhesive composition, and further improve the pot life performance of the adhesive composition.

[0109] When the compound contains a keto-enol tautomer, the content of the keto-enol tautomer is preferably 0.1 parts by mass or more and 3 parts by mass or less relative to 100 parts by mass of the polyfunctional polyisocyanate curing agent (B).

[0110] Within the scope of not impairing the performance of the present invention, various additives may be used in combination with the adhesive composition of this embodiment, in addition to acid-modified polyolefin (A), polyfunctional polyisocyanate curing agent (B), and organoaluminum compound (C). Examples of such additives include flame retardants, pigments, anti-caking adhesives, and fillers.

[0111] As one embodiment, in the adhesive composition of this embodiment, the content of organozirconium compound or organotin compound is preferably less than 0.5 parts by mass relative to 100 parts by mass of acid-modified polyolefin (A), more preferably less than 0.3 parts by mass, even more preferably less than 0.1 parts by mass, even more preferably less than 0.05 parts by mass, particularly preferably less than 0.01 parts by mass, and most preferably 0 parts by mass.

[0112] 2. Laminated body

[0113] The laminate of this embodiment can be obtained by bonding a polyolefin resin substrate to a metal substrate via the adhesive composition of this embodiment.

[0114] As a method for manufacturing the laminate according to this embodiment, conventionally known lamination techniques can be used. For example, the adhesive composition of this embodiment is applied to the surface of a metal substrate using a roller coater, bar coater, or the like, and then dried. After drying, while the adhesive composition layer (adhesive layer) formed on the surface of the metal substrate is in a molten state, a polyolefin resin substrate is laminated (laminated) onto the surface of the adhesive layer to obtain the laminate. The thickness of the adhesive layer formed by 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.

[0115] <Polyolefin resin substrate>

[0116] As the polyolefin resin substrate, well-known polyolefin resins commonly used in the art can be widely used. Examples of polyolefin resin substrates include polyethylene, polypropylene, and ethylene-propylene copolymers. Among these, polypropylene is preferred, and unstretched polypropylene (cast polypropylene) film is more preferred. 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. Furthermore, pigments and various additives can be blended into the polyolefin resin substrate as needed, and surface treatment can also be applied.

[0117] <Metal substrate>

[0118] As the metal substrate, various metals and their alloys, such as aluminum, copper, steel, chromium, zinc, duralumin, and die-casting alloys, can be used. Furthermore, the shapes of the metal substrate can include metal foil, rolled steel sheet, panel, pipe, can, and lid. From the viewpoint of processability, aluminum foil is preferred as the metal substrate. Although it varies depending on the intended use, the metal substrate can generally be used in sheet form with a thickness of 0.01 to 10 mm, preferably 0.02 to 5 mm. Furthermore, the surface of the metal substrate can be pre-treated or left untreated.

[0119] 3. Packaging materials for lithium-ion batteries

[0120] The packaging material for lithium-ion batteries according to this embodiment includes the laminate of this embodiment. The packaging material for lithium-ion batteries is the outer packaging for the lithium-ion battery body.

[0121] As one embodiment, the content of laminates in the packaging material for lithium-ion batteries is generally greater 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.

[0122] As one embodiment, the packaging material for lithium-ion batteries is preferably composed of a laminate.

[0123] The present invention provides an invention in the form shown below.

[0124] Item 1.

[0125] An adhesive composition comprising an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organoaluminum compound (C).

[0126] The weight-average molecular weight (Mw) of the acid-modified polyolefin (A) is in the range of 10,000 to 200,000.

[0127] Item 2.

[0128] According to the adhesive composition of claim 1, the content of the polyfunctional polyisocyanate curing agent (B) is 0.5 to 70 parts by weight relative to 100 parts by weight of the acid-modified polyolefin (A).

[0129] Item 3.

[0130] According to the adhesive composition of item 1 or 2, the content of the organoaluminum compound (C) is 0.01 to 2 parts by weight relative to 100 parts by weight of the acid-modified polyolefin (A).

[0131] Item 4.

[0132] The adhesive composition according to any one of claims 1 to 3, wherein the acid-modified polyolefin (A) is a graft polymer having a structure of a polyolefin grafted with at least one selected from α,β-unsaturated carboxylic acids and their anhydrides.

[0133] Item 5.

[0134] The adhesive composition according to any one of items 1 to 4, wherein the acid value of the acid-modified polyolefin (A) is 2 to 50 mg KOH / g.

[0135] Item 6.

[0136] The adhesive composition according to any one of items 1 to 5, wherein the organoaluminum compound (C) is an aluminum alkoxide compound and / or an aluminum chelate.

[0137] Item 7.

[0138] The adhesive composition according to any one of items 1 to 6 further comprises an organic solvent (D).

[0139] Item 8.

[0140] According to the adhesive composition of item 7, the organic solvent (D) is composed of solvent (D1) and solvent (D2).

[0141] 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.

[0142] The solvent (D2) is at least one solvent selected from the group consisting of alcohol solvents, ketone solvents, ester solvents and glycol ether solvents.

[0143] Item 9.

[0144] According to the adhesive composition of item 8, the mass ratio of solvent (D1) to solvent (D2) (solvent (D1) / solvent (D2)) is 50 / 50 to 97 / 3.

[0145] Item 10.

[0146] The adhesive composition according to any one of items 1 to 9 further comprises a monomer (E) containing an anhydride group.

[0147] Item 11.

[0148] According to the adhesive composition of item 10, the content of the anhydride-containing monomer (E) is 0.1 to 20 parts by weight relative to 100 parts by weight of the acid-modified polyolefin (A).

[0149] Item 12.

[0150] According to the adhesive composition of item 10 or 11, wherein the anhydride-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).

[0151] Item 13

[0152] The adhesive composition according to any one of claims 1 to 12, wherein the content of the polyfunctional polyisocyanate curing agent (B) is more preferably 1 to 65 parts by weight relative to 100 parts by weight of the acid-modified polyolefin (A), even more preferably 2 to 60 parts by weight, even more preferably 3 to 55 parts by weight, even more preferably 6 to 50 parts by weight, particularly preferably 10 to 45 parts by weight, and most preferably 15 to 40 parts by weight.

[0153] Item 14.

[0154] The adhesive composition according to any one of claims 1 to 13, wherein the content of the organoaluminum compound (C) is more preferably 0.05 to 1.5 parts by weight relative to 100 parts by weight of the acid-modified polyolefin (A), even more preferably 0.1 to 1.25 parts by weight, even more preferably 0.2 to 1.0 parts by weight, and particularly preferably 0.3 to 0.95 parts by weight.

[0155] Item 15.

[0156] The adhesive composition according to any one of claims 4 to 14, wherein the polyolefin is generally at least one selected from the group consisting of homopolymer polyethylene, homopolymer polypropylene, and propylene-α-olefin copolymers.

[0157] Preferably, homopolymer polypropylene and / or propylene-α-olefin copolymer,

[0158] More preferably, it is a propylene-α-olefin copolymer.

[0159] Item 16.

[0160] According to the adhesive composition of item 15, the α-olefin in the propylene-α-olefin copolymer is preferably ethylene and / or 1-butene, more preferably 1-butene.

[0161] Item 17.

[0162] According to the adhesive composition of item 15 or 16, the propylene content 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.

[0163] Item 18.

[0164] The adhesive composition according to any one of items 4 to 17, wherein the α,β-unsaturated carboxylic acid and its anhydride are generally maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, succinic acid, citraconic acid, citraconic anhydride, aconitic acid or aconitic anhydride, preferably maleic anhydride.

[0165] Item 19.

[0166] The adhesive composition according to any one of claims 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 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.

[0167] Item 20.

[0168] The adhesive composition according to any one of items 1 to 19, wherein the content of 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.

[0169] Item 21.

[0170] The adhesive composition according to any one of items 1 to 20, wherein the acid-modified polyolefin (A) is preferably maleic anhydride-modified homopolymer polypropylene and / or maleic anhydride-modified propylene-1-butene copolymer, more preferably maleic anhydride-modified homopolymer polypropylene or maleic anhydride-modified propylene-1-butene copolymer.

[0171] Item 22.

[0172] The adhesive composition according to any one of claims 1 to 21, wherein the content of the polyfunctional polyisocyanate curing agent (B) is more preferably 1 to 65 parts by weight relative to 100 parts by weight of the acid-modified polyolefin (A), even more preferably 2 to 60 parts by weight, even more preferably 3 to 55 parts by weight, even more preferably 6 to 50 parts by weight, particularly preferably 10 to 45 parts by weight, and most preferably 15 to 40 parts by weight.

[0173] Item 23.

[0174] The adhesive composition according to any one of claims 1 to 22, wherein the content of the organoaluminum compound (C) is more preferably 0.05 to 1.5 parts by weight relative to 100 parts by weight of the acid-modified polyolefin (A), even more preferably 0.1 to 1.25 parts by weight, even more preferably 0.2 to 1.0 parts by weight, and particularly preferably 0.3 to 0.95 parts by weight.

[0175] Item 24.

[0176] The adhesive composition according to any one of claims 1 to 23, wherein the acid value of the acid-modified polyolefin (A) is more preferably 3 to 45 mg KOH / g, further preferably 5 to 40 mg KOH / g, and particularly preferably 7 to 35 mg KOH / g.

[0177] Item 25.

[0178] The adhesive composition according to any one of items 1 to 24, wherein the multifunctional polyisocyanate curing agent (B) is preferably a diisocyanate compound or a derivative of a diisocyanate compound, more preferably a derivative of a diisocyanate compound.

[0179] Item 26.

[0180] The adhesive composition according to any one of claims 1 to 24, wherein the multifunctional polyisocyanate curing agent (B) is preferably an isocyanurate modified form of a diisocyanate compound and / or a biuret modified form of a diisocyanate compound.

[0181] More preferably, it is at least one selected from the group consisting of isocyanurate modified forms of hexamethylene diisocyanate, adduct modified forms of hexamethylene diisocyanate, biuret modified forms of hexamethylene diisocyanate, urea diketone modified forms of hexamethylene diisocyanate, and urethane modified forms of hexamethylene diisocyanate.

[0182] Particularly preferred are isocyanurate modified forms of hexamethylene diisocyanate and / or biuret modified forms of hexamethylene diisocyanate.

[0183] Item 27.

[0184] The adhesive composition according to any one of items 6 to 26, wherein the aluminum alkoxide compound is at least one selected from the group consisting of aluminum ethoxide, aluminum isopropoxide, aluminum diisopropoxy monosec-butoxide, and aluminum sec-butoxide.

[0185] Item 28.

[0186] The adhesive composition according to any one of items 6 to 27, wherein the organoaluminum compound (C) is an aluminum chelate.

[0187] Item 29.

[0188] According to the adhesive composition of item 28, wherein the aluminum chelate is at least one selected from the group consisting of aluminum diisopropyl acetoacetate, ethyl aluminum diisopropyl acetoacetate, tri(ethylacetoacetyl)aluminum, alkylacetate aluminum diisopropyl ester, bis(ethylacetoacetyl)monoacetylacetonate aluminum and tri(acetylacetonate) aluminum.

[0189] Item 30.

[0190] The adhesive composition according to any one of claims 1 to 29, wherein the content of the organoaluminum compound (C) is more preferably 0.05 to 1.5 parts by weight relative to 100 parts by weight of the acid-modified polyolefin (A), even more preferably 0.1 to 1.25 parts by weight, even more preferably 0.2 to 1.0 parts by weight, and particularly preferably 0.3 to 0.95 parts by weight.

[0191] Item 31.

[0192] According to any one of claims 1 to 30, the content of the organoaluminum compound (C) relative to 100 parts by weight of the polyfunctional polyisocyanate curing agent (B) is preferably 0.05 to 30 parts by weight, more preferably 0.25 to 20 parts by weight, even more preferably 0.5 to 16 parts by weight, even more preferably 0.9 to 12 parts by weight, even more preferably 1.0 to 10 parts by weight, particularly preferably 1.1 to 8 parts by weight, and most preferably 1.2 to 6 parts by weight.

[0193] Item 32.

[0194] The adhesive composition according to any one of claims 7 to 31, wherein the content of the organic solvent (D) relative to 100 parts by weight of the acid-modified polyolefin (A) is preferably 80 to 2000 parts by weight, more preferably 100 to 1600 parts by weight, even more preferably 150 to 1200 parts by weight, even more preferably 200 to 1000 parts by weight, even more preferably 300 to 950 parts by weight, particularly preferably 400 to 900 parts by weight, and most preferably 425 to 800 parts by weight.

[0195] Item 33.

[0196] The adhesive composition according to any one of items 7 to 32, wherein the organic solvent (D) comprises solvent (D1) and solvent (D2),

[0197] The solvent (D1) is an aromatic hydrocarbon solvent or an alicyclic hydrocarbon solvent.

[0198] The solvent (D2) is a ketone solvent.

[0199] Item 34.

[0200] The adhesive composition according to any one of items 7 to 33, wherein the organic solvent (D) comprises solvent (D1) and solvent (D2),

[0201] The solvent (D1) is an alicyclic hydrocarbon solvent.

[0202] The solvent (D2) is a ketone solvent.

[0203] Item 35.

[0204] The adhesive composition according to any one of items 8 to 34, wherein the mass ratio of solvent (D1) to 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.

[0205] Item 36.

[0206] According to any one of claims 10 to 35, the content of the anhydride-containing monomer (E) is more preferably 0.3 parts by mass or more to 10 parts by mass or less, and even more preferably 0.5 parts by mass or more to 8 parts by mass or 1 part by mass or less to 5 parts by mass or less, relative to 100 parts by mass of the acid-modified polyolefin (A).

[0207] Item 37.

[0208] According to any one of items 10 to 36, the adhesive composition wherein the anhydride group contained in the monomer (E) containing the anhydride group is preferably an 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.

[0209] Item 38.

[0210] The adhesive composition according to any one of items 10 to 37, wherein the molecular weight of the anhydride-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.

[0211] Item 39.

[0212] The adhesive composition according to any one of claims 10 to 38, wherein the acid value of the monomer (E) containing the anhydride group is preferably 150 mg KOH / g or more and 800 mg KOH / g or less, more preferably 250 mg KOH / g or more and 600 mg KOH / g or less, and even more preferably 300 mg KOH / g or more and 500 mg KOH / g or less.

[0213] Item 40.

[0214] The adhesive composition according to any one of items 10-39, wherein the monomer (E) containing the anhydride group preferably has a straight-chain alkyl group having 3 or more but less than 20 carbon atoms (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20).

[0215] More preferably, it has a straight-chain alkyl group with 5 or more but less than 18 carbon atoms (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18).

[0216] More preferably, it has a straight-chain alkyl group having 8 or more but less than 16 carbon atoms (8, 9, 10, 11, 12, 13, 14, 15 or 16).

[0217] Particularly preferred are straight-chain alkyl groups having 11 or more but less than 15 carbon atoms (11, 12, 13, 14 or 15).

[0218] Item 41.

[0219] The adhesive composition according to any one of claims 10 to 40, wherein the monomer (E) containing an anhydride group is selected from succinic anhydride, maleic anhydride, glutaric anhydride, butyl succinic anhydride, hexyl succinic anhydride, octyl succinic anhydride, dodecyl succinic anhydride, dodecenyl succinic anhydride, tetrapropylene succinic anhydride, butyl maleic anhydride, pentyl maleic anhydride, hexyl maleic anhydride, octyl maleic anhydride, decyl maleic anhydride, dodecyl maleic anhydride, butyl glutaryl maleic anhydride, etc. At least one of the following groups: amino acid anhydride, hexylglutamic acid anhydride, heptylglutamic acid anhydride, octylglutamic acid anhydride, decylglutamic acid anhydride, dodecylglutamic acid anhydride, pyromellitic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltrihydrophthalic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexenedicarboxylic anhydride, hysteretic anhydride, and tetrabromophthalic anhydride.

[0220] Item 42.

[0221] The adhesive composition according to any one of items 10 to 40, wherein the monomer (E) containing the anhydride group is dodecenyl succinic anhydride.

[0222] Item 43.

[0223] According to any one of claims 1 to 42, the adhesive composition wherein the content of the organozirconium compound or organotin compound in the adhesive composition is preferably less than 0.5 parts by mass relative to 100 parts by mass of the acid-modified polyolefin (A), more preferably less than 0.3 parts by mass, even more preferably less than 0.1 parts by mass, even more preferably less than 0.05 parts by mass, particularly preferably less than 0.01 parts by mass, and most preferably 0 parts by mass.

[0224] Item 44.

[0225] The adhesive composition according to any one of items 1 to 43 is used for bonding a polyolefin resin substrate to a metal substrate.

[0226] Item 45.

[0227] A laminate formed by bonding a polyolefin resin substrate to a metal substrate via an adhesive composition as described in any one of claims 1 to 43.

[0228] Item 46.

[0229] A packaging material for lithium-ion batteries comprising the laminate described in item 45.

[0230]

Example

[0231] The present invention will be further described in detail below with reference to specific embodiments. However, the present invention is not limited to these embodiments. Hereinafter, "room temperature" refers to a temperature in the range of 20°C to 25°C.

[0232] Determination of acid value

[0233] The acid value (mgKOH / g) of acid-modified polyolefin (A) indicates the amount of KOH required to neutralize 1g of acid-modified polyolefin (A). The acid value of acid-modified polyolefin (A) is determined according to the test method of JIS K 0070 (1992). Specifically, 1g of acid-modified polyolefin (A) is dissolved in 100g of xylene adjusted to 100°C, and titrated at 100°C with phenolphthalein as an indicator using a 0.1mol / L potassium hydroxide ethanol solution [trade name "0.1mol / L ethanolic potassium hydroxide solution", manufactured by Wasoku Chunqiu Co., Ltd.]. At this time, the amount of potassium hydroxide required for titration is converted to mg, and the acid value (mgKOH / g) of acid-modified polyolefin (A) is calculated.

[0234] Determination of the ratio of acetone extract components

[0235] Using a Soxhlet extractor, the acetone extraction ratio (mass%) of acid-modified polyolefin (A) was determined after reflux with acetone for 2 hours. Specifically, 50 g of acid-modified polyolefin (A) was weighed into a Soxhlet extraction tube, and a condenser was assembled into a flat-bottomed flask containing 1100 mL of acetone. The mixture was then refluxed in a 90°C water bath for 2 hours to extract acetone. The filter paper was then removed, and the acetone extract in the flat-bottomed flask was distilled off. The weight (g) of the residue after drying under reduced pressure at 100°C for 1 hour was further measured. The acetone extraction ratio of acid-modified polyolefin (A) was calculated using the following formula.

[0236] The acetone extract ratio (mass%) of acid-modified polyolefin (A) = (weight of extract residue / sample size) × 100

[0237] Determination of storage modulus (E') at 25℃

[0238] The storage modulus (E') (MPa) of acid-modified polyolefin (A) was determined according to the test method of JIS K 7244-4 (1999). Specifically, 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 coated onto TEFLON (registered trademark) sheets to a thickness of approximately 50 μm and then dried to obtain a dried coating. The coating was cut into pieces 5 mm wide and 25 mm long to serve as test pieces. For these test pieces, the storage modulus (E') (MPa) at 25 °C was measured using a dynamic viscoelasticity measuring device (manufactured by IT Measurement Control Co., Ltd., "DVA-200") at a frequency of 10 Hz, heated from -50 °C to 80 °C at a rate of 5 °C / min.

[0239] Determination of tensile elongation at break (Eb) at 25℃

[0240] The tensile elongation at break (Eb) (%) of acid-modified polyolefin (A) was determined according to the test method of JIS K 7161 (2014). Specifically, 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 coated onto TEFLON (registered trademark) sheet to a thickness of 50 μm and dried to obtain a dried coating film. The coating film was cut into pieces 15 mm wide and 70 mm long to serve as test pieces. Tensile tests were performed on the obtained test pieces using a tensile testing machine (TENSILON RTM-100 manufactured by Orient Corporation) at 25°C, with a clamp spacing of 40 mm and a tensile speed of 50 mm / min. The tensile elongation at break (%) of the test piece was calculated using the following formula.

[0241] The tensile elongation at break (Eb) (%) of acid-modified polyolefin (A) = [(length of the test piece at fracture - length of the test piece before the test) / length of the test piece at fracture] × 100

[0242] Determination of weight-average molecular weight (Mw)

[0243] The weight-average molecular weight (Mw) of the acid-modified polyolefin (A) was measured using a gel permeation chromatograph Alliance e2695 manufactured by Waters K.K. of Japan. The measurement conditions for gel permeation chromatography (GPC) were set as follows. Standard curves were obtained by separately dissolving “Molecular weight standard substance (liposoluble polymer) MW500: model 2012-2”, “Molecular weight standard substance (liposoluble polymer) MW 2,000: model 2012-5”, “Molecular weight standard substance (liposoluble polymer) MW10,000: model 2012-9”, “Molecular weight standard substance (liposoluble polymer) MW20,000: model 2013-1”, “Molecular weight standard substance (liposoluble polymer) MW50,000: model 2013-3”, and “Molecular weight standard substance (liposoluble polymer) MW200,000: model 2013-7” manufactured by GL Sciences Inc. at a concentration of 0.5% each to prepare tetrahydrofuran solutions, filtering them, filling them into sample bottles, and measuring them.

[0244] <GPC measurement conditions>

[0245] · Standard substance: Polystyrene resin (weight-average molecular weights 500, 2,000, 50,000, 200,000)

[0246] · Concentration of acid-modified polyolefin (A): 0.5% by mass

[0247] · Mobile phase: Tetrahydrofuran (THF)

[0248] · Column: Shodex KF-806 + KF-803

[0249] · Column temperature: 40 °C

[0250] · Flow rate: 1.0 ml / minute

[0251] · Detector: Photodiode array detector (wavelength 254 nm = ultraviolet light)

[0252] Determination of melting point (Tm) and heat of fusion (ΔH)

[0253] The melting point of the acid-modified polyolefin (A) was measured as described below (Tm)(°C) and the heat of fusion ( △H(J / g). Specifically, using a differential scanning calorimeter (DSC) (manufactured by TA Instruments Japan, Q-2000), approximately 5 mg of acid-modified polyolefin (A) as the sample was heated from -50°C to 250°C at a rate of 20°C / min, held in a molten state for 5 minutes, then cooled at a rate of 5°C / min, held at -50°C for 5 minutes, and then further heated from -50°C to 250°C at a rate of 5°C / min. The temperature at which the peak of the melt occurs during melting was taken as the melting point (Tm). Furthermore, the heat of fusion (ΔH) was calculated based on the integral value of this melting peak. In addition, when multiple peaks were detected during the measurement, the temperature of the peak detected at the highest temperature side and the integral value of the peak were taken as the melting point (Tm) and heat of fusion (ΔH) of the acid-modified polyolefin (A), respectively.

[0254] <Example of manufacturing acid-modified polyolefin (A)>

[0255] Manufacturing Example 1

[0256] Add 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 elongation at break 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 to a 1L autoclave. Heat to 140°C and stir for 1 hour (here, "reaction" refers to 1 hour). Then, cool the resulting reaction solution to 100°C and, while stirring, pour it into a container containing 717 parts by mass of toluene and 950 parts by mass of methyl ethyl ketone preheated to 40°C. Cool to 40°C, stir for 30 minutes, and then further cool to 25°C to allow resin precipitation (here, the operation of injecting the reaction solution into a solvent such as methyl ethyl ketone while stirring and then cooling to allow resin precipitation is called "reprecipitation"). Then, the acid-modified propylene-1-butene copolymer grafted with maleic anhydride is separated from the (poly)maleic anhydride and low molecular weight compounds by centrifugation of the slurry containing the resin. Further, while stirring, the centrifuged acid-modified propylene-1-butene copolymer is added to a new container containing 2000 parts by weight of methyl ethyl ketone (MEK) preheated to 25°C, and stirring is continued for 1 hour. Then, the acid-modified propylene-1-butene copolymer is further separated from the (poly)maleic anhydride and low molecular weight compounds by centrifugation of the slurry. This process is repeated twice to complete the purification (here, the process of adding the centrifuged acid-modified propylene-1-butene copolymer to MEK while stirring, and then centrifuging again to enhance purification, is called "reslurry"). After purification, the product was dried at 70°C under reduced pressure for 5 hours to obtain an acid-modified polyolefin maleic anhydride-modified propylene-1-butene copolymer A-1 (propylene content 78 mol%, 1-butene content 22 mol%, acid value 2 mg KOH / g, acetone extract ratio 0.1 mass, storage modulus (E') 300 MPa at 25°C, tensile elongation at break (Eb) 600% at 25°C, weight-average molecular weight (Mw) 190,000, melting point (Tm) 78°C, heat of fusion (ΔH) 37 J / g).

[0257] Manufacturing Example 2

[0258] Except for changing the amount of maleic anhydride to 3 parts by mass, changing the number of re-slurrying times to 1, and changing the amount of methyl ethyl ketone added during re-slurrying to 1000 parts by mass, the same as in Manufacturing Example 1, maleic anhydride modified propylene-1-butene copolymer A-2 (propylene content 78 mol%, 1-butene content 22 mol%, acid value 5 mg KOH / g, acetone extraction ratio 1.8 wt%, storage modulus (E') 280 MPa at 25°C, tensile elongation at break (Eb) 650% at 25°C, weight-average molecular weight (Mw) 180,000, melting point (Tm) 78°C, heat of fusion (ΔH) 36 J / g) was obtained.

[0259] Manufacturing Example 3

[0260] Except for changing the amount of toluene to 150 parts by mass, the amount of maleic anhydride to 40 parts by mass, the amount 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 re-slurrying times to 5, the same as in Manufacturing Example 1, maleic anhydride modified propylene-1-butene copolymer A-3 was obtained (propylene content 78 mol%, 1-butene content 22 mol%, acid value 48 mg KOH / g, acetone extraction ratio 0.1 mass, storage modulus (E') at 25°C 180 MPa, tensile elongation at break (Eb) at 25°C 350%, weight-average molecular weight (Mw) 31,000, melting point (Tm) 75°C, heat of fusion (ΔH) 31 J / g).

[0261] Manufacturing Example 4

[0262] Except for changing the amount of toluene to 150 parts by mass, the amount of maleic anhydride to 40 parts by mass, the amount 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, the solvent used for re-slurrying to 1000 parts by mass of methyl ethyl ketone, and the number of re-slurrying times to 3 times, the same as in Manufacturing Example 1, maleic anhydride modified propylene-1-butene copolymer A-4 (propylene content 78 mol%, 1-butene content 22 mol%, acid value 48 mg KOH / g, acetone extraction ratio 1.8 wt%, storage modulus (E') at 25°C 150 MPa, tensile elongation at break (Eb) at 25°C 300%, weight-average molecular weight (Mw) 27,000, melting point (Tm) 75°C, heat of fusion (ΔH) 30 J / g) was obtained.

[0263] Manufacturing Example 5

[0264] Except for changing the amount of toluene to 150 parts by mass, the amount of maleic anhydride to 20 parts by mass, the amount of di-tert-butyl peroxide to 6 parts by mass, the reaction time to 3 hours, the solvent used for reprecipitation to 700 parts by mass of methyl ethyl ketone, the solvent used for re-slurrying to 1000 parts by mass of methyl ethyl ketone, and the number of re-slurrying times to 2, the same as in Manufacturing Example 1, maleic anhydride modified propylene-1-butene copolymer A-5 (propylene content 78 mol%, 1-butene content 22 mol%, acid value 25 mg KOH / g, acetone extraction ratio 0.9 mass), storage modulus (E') at 25°C 400 MPa, tensile elongation at break (Eb) at 25°C 500%, weight-average molecular weight (Mw) 60,000, melting point (Tm) 77°C, heat of fusion (ΔH) 35 J / g.

[0265] Manufacturing Example 6

[0266] Except for changing the amount of propylene-1-butene copolymer (propylene content 70 mol%, 1-butene content 30 mol%, storage modulus at 25℃ 52 MPa, tensile elongation at break at 25℃ 1050%) to 100 parts by mass, the amount of toluene to 150 parts by mass, the amount of maleic anhydride to 30 parts by mass, the amount of di-tert-butyl peroxide to 6 parts by mass, the reaction time to 3 hours, the solvent for reprecipitation to 700 parts by mass of methyl ethyl ketone, and the solvent for re-slurrying to 1000 parts by mass of methyl ethyl ketone. Except for changing the number of acetone and re-slurrying times to 2, the same as in Manufacturing Example 1, maleic anhydride modified propylene-1-butene copolymer A-6 was obtained (propylene content 70 mol%, 1-butene content 30 mol%, acid value 25 mg KOH / g, acetone extraction ratio 1.0 mass%, storage modulus (E') at 25°C 12 MPa, tensile elongation at break (Eb) at 25°C 900%, weight-average molecular weight (Mw) 60,000, melting point (Tm) 58°C, heat of fusion (ΔH) 7 J / g).

[0267] Manufacturing Example 7

[0268] Except for changing the amount of homopolymer polypropylene (propylene homopolymer, storage modulus of 2100 MPa at 25°C, elongation at break of 900% at 25°C) to 100 parts by mass, the amount of toluene to 150 parts by mass, the amount of maleic anhydride to 30 parts by mass, the amount of di-tert-butyl peroxide to 6 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 solvent used for re-slurrying to 1000 parts by mass... Except for changing the amount of methyl ethyl ketone and the number of re-slurrying times to 2, the same as in Manufacturing Example 1, maleic anhydride modified homopolymer polypropylene A-7 was obtained (acid value 25 mg KOH / g, acetone extract ratio 0.9% by mass, storage modulus (E') 1800 MPa at 25°C, elongation at break (Eb) 60% at 25°C, weight-average molecular weight (Mw) 60,000, melting point (Tm) 75°C, heat of fusion (ΔH) 5 J / g).

[0269] Manufacturing Example 8

[0270] Except for changing the amount of propylene-1-butene copolymer (propylene content 90 mol%, 1-butene content 10 mol%, storage modulus at 25℃ 2720 MPa, tensile elongation at break at 25℃ 400%) to 100 parts by mass, the amount of toluene to 186 parts by mass, the amount of maleic anhydride to 20 parts by mass, the amount of di-tert-butyl peroxide to 6 parts by mass, the reaction time to 3 hours, the solvent for reprecipitation to 700 parts by mass of methyl ethyl ketone, and the solvent for re-slurrying to 1000 parts by mass of methyl ethyl ketone. Except for changing the number of ketones and re-slurrying times to 2, the same as in Manufacturing Example 1, maleic anhydride modified propylene-1-butene copolymer A-8 was obtained (propylene content 90 mol%, 1-butene content 10 mol%, acid value 25 mg KOH / g, acetone extraction ratio 1.0 mass%, storage modulus (E') 2350 MPa at 25°C, tensile elongation at break (Eb) 38% at 25°C, weight-average molecular weight (Mw) 60,000, melting point (Tm) 125°C, heat of fusion (ΔH) 63 J / g).

[0271] Manufacturing Example 9

[0272] Except for changing the amount of propylene-1-butene copolymer (propylene content 78 mol%, 1-butene content 22 mol%, storage modulus at 25℃ 320 MPa, tensile elongation at break at 25℃ 760%) to 100 parts by mass, the amount of toluene to 186 parts by mass, the amount of maleic anhydride to 0.5 parts by mass, the amount of di-tert-butyl peroxide to 0.1 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 solvent used for re-slurrying to 10 parts by mass. Apart from 0.00 parts by mass of methyl ethyl ketone, in the same manner as in Manufacturing Example 1, maleic anhydride modified propylene-1-butene copolymer A-9 (propylene content 78 mol%, 1-butene content 22 mol%, acid value 1 mg KOH / g, acetone extract ratio 0.1 mol% by mass, storage modulus (E') 290 MPa at 25°C, elongation at break (Eb) 700% at 25°C, weight-average molecular weight (Mw) 210,000, melting point (Tm) 78°C, heat of fusion (ΔH) 40 J / g) was obtained.

[0273] Manufacturing Example 10

[0274] Except for changing the amount of propylene-1-butene copolymer (propylene content 90 mol%, 1-butene content 10 mol%, storage modulus at 25℃ 2720 MPa, tensile elongation at break at 25℃ 400%) to 100 parts by mass, the amount of toluene to 186 parts by mass, the amount of maleic anhydride to 25 parts by mass, the amount of di-tert-butyl peroxide to 9 parts by mass, the reaction time to 5 hours, the solvent used for reprecipitation to 700 parts by mass of methyl ethyl ketone, and the solvent used for re-slurrying to 1000 parts by mass of methyl ethyl ketone. Except for changing the number of acetone and re-slurrying times to 2, the same as in Manufacturing Example 1, maleic anhydride modified propylene-1-butene copolymer A-10 (propylene content 90 mol%, 1-butene content 10 mol%, acid value 25 mg KOH / g, acetone extraction ratio 1.0 mass%, storage modulus (E') 200 MPa at 25°C, tensile elongation at break (Eb) 35% at 25°C, weight-average molecular weight (Mw) 9,000, melting point (Tm) 75°C, heat of fusion (ΔH) 35 J / g) was obtained.

[0275] (Preparation of Main Agent 1)

[0276] To a 500 ml four-necked flask equipped with a water-cooled reflux condenser and a stirrer, add 100 parts by mass of the maleic anhydride-modified propylene-1-butene copolymer (A-1) obtained in Manufacturing Example 1, 5 parts by mass of (E-1) as the anhydride-containing monomer (E), 417 parts by mass of solvent (D1) (methylcyclohexane), and 179 parts by mass of solvent (D2) (methyl ethyl ketone) as the organic solvent (D). While stirring, the mixture is heated to 80°C and stirred continuously at 80°C for 1 hour. Then, it is cooled to room temperature to obtain main agent 1. The mixing amount and solution state of main agent 1 are shown in Table 1.

[0277] (Preparation of main agents 2~19)

[0278] Except for the changes to the acid-modified polyolefin (A), organic solvent (D), and anhydride-containing monomer (E) as shown in Table 1, main agents 2-19 were prepared using the same method as main agent 1. The mixing amounts and solution states of main agents 2-19 are shown in Table 1.

[0279] Table 1

[0280]

[0281] The materials used in the embodiments and comparative examples are described below.

[0282] <Multifunctional Polyisocyanate Curing Agent (B)>

[0283] B-1: Isocyanurate modified form of hexamethylene diisocyanate, SUMIDUR (registered trademark) N-3300 (manufactured by Bayer AG).

[0284] B-2: Biuret modified form of hexamethylene diisocyanate, DURANATE (registered trademark) 24A-100 (manufactured by Asahi Kasei Chemicals Co., Ltd.)

[0285] <Organoaluminum compounds (C)>

[0286] C-1: Di(ethylacetoacetyl)aluminum monoacetylacetonate (manufactured by Kawaken Fine Chemicals Co., Ltd., "Alumichelate D")

[0287] <Other organometallic compounds X>

[0288] X-1: Organozirconium compound (Zirconium tetraacetylacetonate) (manufactured by Matsumoto Fine Chemicals Co., Ltd., "ORGATIX ZC700")

[0289] X-2: Organotin compound (dibutyltin dilaurate) (manufactured by Tokyo Kogyo Kasei Co., Ltd., industrial reagent)

[0290] <Monomers containing anhydride groups (E)>

[0291] E-1: Dodecenylsuccinic anhydride (RIKACID DDSA manufactured by Shin Nippon Rikka Co., Ltd., molecular weight 266 g / mol, acid value 417 mg KOH / g)

[0292] (Example 1)

[0293] Mix 667 parts by weight of the main agent 1, 35 parts by weight of SUMIDUR (registered trademark) N-3300 (B-1) as a polyfunctional polyisocyanate curing agent (B), and 0.5 parts by weight of (C-1) as an organoaluminum compound (C), and stir with a magnetic stirrer for 10 minutes in an atmosphere of 25°C to obtain an adhesive composition.

[0294] (Examples 2-22, Comparative Examples 1-6)

[0295] Except for the main agents 2-19, the polyfunctional polyisocyanate curing agent (B), and the organoaluminum compound (C) as shown in Tables 2 and 3, the adhesive composition was obtained using the same method as in Example 1.

[0296] Table 2

[0297]

[0298] Table 3

[0299]

[0300] Evaluation of solution state

[0301] Regarding the solution state of main agents 1-19, the solution viscosity (mPa·s) at 25°C was measured using a Brookfield TVB-10M viscometer (hereinafter sometimes referred to as a Type B 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 used as an evaluation of the solution state. The evaluation results are shown in Table 1.

[0302] <Evaluation Criteria>

[0303] ◎ (Excellent in practical application): Less than 200 mPa·s

[0304] ○ (Applicable to): 200 mPa·s and above, less than 1000 mPa·s

[0305] × (Not applicable): Viscosity above 1000 mPa·s or where gelation makes viscosity impossible to measure.

[0306] Evaluation of service life performance

[0307] Pot life performance refers to the stability of the adhesive composition. When the pot life performance is good, the viscosity of the composition increases less and it can be stored for a long time. When the pot life performance is poor, the viscosity of the composition increases, and if the increase is large, gelation occurs, making it impossible to store for a long time and difficult to coat onto the substrate. The pot life performance of the adhesive compositions obtained in Examples 1-22 and Comparative Examples 1-6 was evaluated according to the thickening rate (%) shown below. Specifically, each main agent, polyfunctional polyisocyanate curing agent (B) and organoaluminum compound (C) were mixed at the ratios shown in Tables 2-3 and stored in a stirred state for 8 hours immediately and in an atmospheric atmosphere at 25°C. The solution viscosity at 25°C was measured using a type B viscometer, and the thickening rate was calculated according to the following formula (1). The calculated thickening rate was evaluated according to the following evaluation criteria and used as the evaluation of the pot life performance. The evaluation results are shown in Tables 2-3.

[0308] Thickening rate (%) = {(viscosity of the adhesive composition at 25°C after 8 hours of stirring - viscosity of the adhesive composition at 25°C immediately after mixing) / viscosity of the adhesive composition at 25°C immediately after mixing} × 100……(Equation 1)

[0309] <Evaluation Criteria>

[0310] ◎ (Excellent in practical application): Less than 50%

[0311] ○ (Practical): 50% or more, less than 200%

[0312] × (Not applicable): Viscosity exceeding 200% or unmeasurable due to gelation.

[0313] Fabrication of metal substrate and polyolefin resin substrate laminate

[0314] Aluminum foil (manufactured by Sumitomo Aluminum Foil Co., Ltd., 8079-0, 40 μm thick) was used as the metal substrate, and unstretched polypropylene film (PYLEN Firm CT manufactured by Toyobo Co., Ltd., 40 μm thick) (hereinafter also referred to as CPP film) was used as the polyolefin resin substrate. The adhesive compositions obtained in Examples 1-22 and Comparative Examples 1-6 were coated onto the metal substrate using a bar coater, so that the film thickness of the dried adhesive layer was 3 μm. The coated surface was dried in a 100°C atmosphere for 1 minute using a hot air dryer to obtain a metal substrate with an adhesive layer laminated with a film thickness of 3 μm. The polyolefin resin substrate was overlapped with the surface of the above adhesive layer, and the laminate was obtained by laminating at a lamination temperature of 80°C or 120°C, a pressure of 0.3 MPa, and a speed of 1 m / min using a small benchtop test laminator (SA-1010-S) manufactured by Testech Industries Co., Ltd., and curing at 40°C and 50% RH for 96 hours.

[0315] For the laminate obtained as described above, evaluate the adhesiveness, heat resistance at 80°C, electrolyte resistance, and formability respectively according to the following methods.

[0316] Evaluation of adhesiveness

[0317] Cut the laminate obtained above into a size of 100 mm × 15 mm to make a test piece, and evaluate the adhesiveness of this test piece through the following T-peel test.

[0318] <T-peel test>

[0319] According to the test method of ASTM-D1876-61, use TENSILON RTM-100 manufactured by Orient Corporation to measure the peel strength (N / cm) 5 times at a tensile speed of 50 mm / min in an environment of 25°C, and take the average value as the peel strength (N / cm) of the above test piece. Evaluate the peel strength (N / cm) of the obtained test piece according to the following evaluation criteria, and use it as the evaluation of adhesiveness. The evaluation results are shown in Tables 2 to 3.

[0320] <Evaluation criteria>

[0321] ☆ (Particularly excellent in practical use): 12.0 N / cm or more

[0322] ◎ (Excellent in practical use): 10.0 N / cm or more and less than 12.0 N / cm

[0323] ○ (Practicable): 7.0 N / cm or more and less than 10.0 N / cm

[0324] × (Not practicable): Less than 7.0 N / cm

[0325] Evaluation of heat resistance

[0326] Cut the laminate obtained above into a size of 100 mm × 15 mm to make a test piece, and evaluate the heat resistance of this test piece through the T-peel test in a constant temperature bath at 80°C. Specifically, use AG-IS manufactured by Shimadzu Corporation equipped with a constant temperature bath, install the above test piece in the constant temperature bath heated to 80°C, maintain the temperature in the bath at 80°C for 5 minutes, and then measure the peel strength (N / cm) 5 times at a tensile speed of 50 mm / min in an environment of 80°C, and take the average value as the peel strength (N / cm) of the above test piece. Evaluate the peel strength (N / cm) of the obtained test piece according to the following evaluation criteria, and use it as the evaluation of heat resistance. The evaluation results are shown in Tables 2 to 3.

[0327] (Evaluation criteria)

[0328] ☆ (Particularly excellent in practical use): 6.0 N / cm or more

[0329] ◎ (Excellent in practical use): 4.5 N / cm or more and less than 6.0 N / cm

[0330] ○ (Practicable): 3.0 N / cm or more and less than 4.5 N / cm

[0331] × (Not practicable): Less than 3.0 N / cm

[0332] Evaluation of electrolyte resistance

[0333] In order to discuss the usability as a packaging material for LiB, the electrolyte resistance (chemical resistance to the electrolyte) was evaluated by the peel strength (N / cm) shown below. First, the laminate obtained above was cut into a size of 100 mm × 15 mm to prepare a test piece, which was immersed in an electrolyte [lithium hexafluorophosphate added to ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 (volume ratio)] at 85°C for 7 days. Then, the test piece was taken out from the electrolyte, washed with ion-exchanged water, wiped with a paper towel to remove water, and dried sufficiently. Next, a T-peel test was performed on the dried test piece according to the same procedure as the above <T-peel test>, and the peel strength (N / cm) of the obtained test piece was evaluated based on the following evaluation criteria, which was used as the evaluation of the electrolyte resistance. The evaluation results are shown in Tables 2 to 3.

[0334] <Evaluation criteria>

[0335] ☆ (Particularly excellent in practical use): 8.0 N / cm or more

[0336] ◎ (Excellent in practical use): 6.5 N / cm or more and less than 8.0 N / cm

[0337] ○ (Practicable): 5.0 N / cm or more and less than 6.5 N / cm

[0338] × (Not practicable): Less than 5.0 N / cm

[0339] Evaluation of formability

[0340] To discuss its applicability as a packaging material for LiB, a formability evaluation based on a deep-drawing testing machine was conducted. First, the laminate obtained above was cut to a size of 80mm × 120mm and used as test pieces for cold forming. Specifically, using a stretch forming machine (model: TP-25C-X2) manufactured by Amada Corporation (a deep-drawing testing machine), a forming die (concave die) with a diameter of 55mm × 35mm, and a corresponding forming die (convex die), 10 test pieces were cold-formed at various forming depths, starting from 0.5mm and changing the forming depth in 0.5mm increments, in a 25°C atmosphere with a pressure bar of 0.4MPa. For the cold-formed test pieces, the deepest forming depth (mm) among the 10 test pieces where no wrinkles, aluminum foil pinholes, cracks, etc., were produced was defined as the limit forming depth (mm) of that test piece. The limit forming depth (mm) of the obtained test pieces was evaluated according to the following evaluation criteria and used as the formability evaluation. The evaluation results are shown in Tables 2-3.

[0341] <Evaluation Criteria>

[0342] ☆ (Exceptionally excellent in practical use): Maximum forming depth of 6.0mm or more

[0343] ◎ (Excellent in practical application): Limit forming depth of 4.0mm or more, less than 6.0mm

[0344] ○ (Practical): Maximum forming depth ≥2.0mm, <4.0mm

[0345] × (Not applicable): Limit forming depth less than 2.0mm

[0346] [Analysis of Results in Tables 2 and 3]

[0347] The adhesive compositions obtained in Examples 1-22 exhibit good pot life performance. Furthermore, the metal substrate-polyolefin resin substrate laminates obtained using the adhesive compositions obtained in Examples 1-22, after lamination at lamination temperatures of 80°C or 120°C and followed by low-temperature, short-time curing at 40°C for 96 hours, demonstrate good adhesion, heat resistance, electrolyte resistance (chemical resistance to electrolyte), and formability.

[0348] On the other hand, the adhesive composition obtained in Comparative Example 1, lacking a polyfunctional polyisocyanate curing agent (B), exhibited extremely poor adhesion, heat resistance, and formability. Furthermore, regarding the electrolyte resistance of Comparative Example 1, it could not be determined because the CPP film peeled off from the aluminum foil when the test piece was immersed in the electrolyte.

[0349] The adhesive composition obtained in Comparative Example 2 had extremely poor heat resistance because it did not contain organoaluminum compound (C).

[0350] In the adhesive composition obtained in Comparative Example 3, the heat resistance was extremely poor because an organozirconium compound (X-1) was used instead of an organoaluminum compound (C).

[0351] In the adhesive composition obtained in Comparative Example 4, the pot life performance was extremely poor because an organotin compound (X-2) was used instead of an organoaluminum compound (C).

[0352] In the adhesive composition obtained in Comparative Example 5, the heat resistance and electrolyte resistance were extremely poor because the main agent 18 was made from A-9 with a weight-average molecular weight of up to 210,000.

[0353] In the adhesive composition obtained in Comparative Example 6, the heat resistance and formability were extremely poor because the main agent 19 was made using A-10 with a weight-average molecular weight as low as 9000.

[0354] [Industry Applicability]

[0355] The adhesive composition of this embodiment exhibits excellent pot life performance, adhesion, heat resistance, chemical resistance to electrolytes, and formability. Therefore, the polyolefin resin substrate and metal substrate laminate formed from the adhesive composition of this embodiment can be used not only in the fields of appliance outer panels, furniture materials, and building interior components, but also widely in packaging materials (soft-pack form) for lithium batteries used in personal computers, mobile phones, cameras, etc.

Claims

1. An adhesive composition, characterized in that, It contains acid-modified polyolefin (A), polyfunctional polyisocyanate curing agent (B), and organoaluminum compound (C). 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 weight relative to 100 parts by weight 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 relative to 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 of polyolefin grafted with at least one of α,β-unsaturated carboxylic acids and their anhydrides.

5. The adhesive composition according to claim 1, wherein, The acid value of the acid-modified polyolefin (A) is 2~50 mg KOH / g.

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

7. The adhesive composition according to claim 1, wherein, It further contains organic solvents (D).

8. The adhesive composition according to claim 7, wherein, The organic solvent (D) is composed of solvent (D1) and 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. 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 solvent (D1) to solvent (D2), i.e., solvent (D1) / solvent (D2), is 50 / 50 to 97 / 3.

10. The adhesive composition according to claim 1, wherein, It further contains monomers (E) containing an anhydride group.

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

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

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

14. A laminate formed by bonding a polyolefin resin substrate to a metal substrate via an adhesive composition according to any one of claims 1 to 12.

15. A packaging material for lithium-ion batteries comprising the laminate of claim 14.

Images