JP2024089905A - Adhesives, laminates, battery packaging materials and batteries - Google Patents

Abstract

The present invention provides an adhesive that has excellent adhesion and heat resistance between a non-polar substrate such as an olefin resin and a metal substrate even when aged at low temperatures, a laminate obtained using the adhesive, and a battery packaging material.
[Solution] A two-component curing adhesive for lithium-ion battery exterior materials, comprising a composition (X) containing a hydroxyl-modified polyolefin (A) and a composition (Y) containing a polyisocyanate compound (B), wherein the hydroxyl-modified polyolefin (A) has crystallinity and is a polymer of an α-olefin having 2 to 20 carbon atoms, a laminate obtained using the adhesive, and a battery packaging material.
[Selection diagram] None

Description

The present invention relates to an adhesive, more specifically, an adhesive suitable for bonding a resin substrate and a metal substrate, a laminate obtained using the adhesive, an exterior material for a secondary battery, and a battery.

A secondary battery, such as a lithium-ion battery, is configured with a positive electrode, a negative electrode, and an electrolyte or the like sealed between them. It is also known to use a heat seal layer made of an olefin resin and a laminate made of a metal foil such as aluminum foil or a metal deposition layer and a metal base material and a plastic laminate as a sealing bag for enclosing the lead wires for taking out electricity from the positive and negative electrodes (Patent Documents 1 and 2).

Japanese Patent Application Laid-Open No. 09-283101 JP 2007-294381 A

When bonding a heat seal layer made of an olefin resin to a metal substrate via an adhesive, a so-called aging process is generally performed in which the adhesive is heated to promote hardening. The aging temperature and aging time in the aging process can be selected as appropriate, but as an example, it is preferable to perform the aging process at 80°C or less, where the thermal shrinkage effect of the olefin resin is small. On the other hand, the lower the aging temperature and the shorter the aging time, the less likely the adhesive properties will be exhibited.

The present invention has been made in view of these circumstances, and aims to provide an adhesive that has excellent adhesion between a non-polar substrate such as an olefin resin and a metal substrate, even when aged at low temperatures. It also aims to provide a laminate obtained using such an adhesive, and a secondary battery exterior material and a battery obtained using the laminate.

The present invention relates to a two-component curing adhesive for lithium-ion battery exterior materials, which comprises a composition (X) containing a hydroxyl-modified polyolefin (A) and a composition (Y) containing a polyisocyanate compound (B), in which the hydroxyl-modified polyolefin (A) is crystalline and is a polymer of an α-olefin having 2 to 20 carbon atoms.

The adhesive of the present invention has excellent adhesion between non-polar substrates such as olefin resins and metal substrates even when aged at low temperatures, and maintains its adhesion even when immersed in a solvent. Furthermore, the laminate of the present invention has excellent adhesion and solvent resistance.

<Adhesive>
The two-component adhesive of the present invention comprises a composition (X) containing a hydroxyl-modified polyolefin (A) and a composition (Y) containing a polyisocyanate compound (B), and the hydroxyl-modified polyolefin (A) has crystallinity and is a crystalline polymer of an α-olefin having from 2 to 20 carbon atoms. Each component of the adhesive of the present invention will be described in detail below.

(Composition (X))
(Hydroxyl Group-Modified Polyolefin (A))
The composition (X) contains a hydroxyl-modified polyolefin (A). The hydroxyl-modified polyolefin (A) is a resin in which a polymer of an α-olefin having 2 to 20 carbon atoms is modified with a hydroxyl-containing polymerizable monomer. This makes it possible to obtain an adhesive having excellent adhesion, solvent resistance, electrolyte resistance, and the like.

Examples of α-olefins having 2 to 20 carbon atoms include α-olefins having 2 or 3 carbon atoms, such as ethylene and propylene, and α-olefins having 4 to 20 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. It is preferable to use at least one selected from ethylene, propylene, and 1-butene, and it is preferable to use at least one selected from propylene and 1-butene, and it is preferable to include propylene and 1-butene.

The polymer of an α-olefin having 2 to 20 carbon atoms may be a homopolymer or a copolymer. The copolymer may be a block copolymer or a random copolymer. A copolymer of an α-olefin having 2 to 20 carbon atoms is preferable.

Polymers of α-olefins having 2 to 20 carbon atoms may be made from polymerizable monomers other than α-olefins having 2 to 20 carbon atoms. Examples of such polymerizable monomers include conjugated polyenes such as butadiene and isoprene, and non-conjugated polyenes such as 1,4-hexadiene, 1,7-octadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-vinyl-2-norbornene, 5-methylene-2-norbornene, and 2,5-norbornadiene.

Examples of hydroxyl group-containing polymerizable monomers include hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, glycerin mono(meth)acrylate, pentaerythritol mono(meth)acrylate, trimethylolpropane mono(meth)acrylate, tetramethylolethane mono(meth)acrylate, butanediol mono(meth)acrylate, acrylate, polyethylene glycol mono(meth)acrylate, 2-(6-hydrohexanoyloxy)ethyl acrylate, 2-(meth)acryloyloxyethyl acid phosphate and other hydroxyl group-containing (meth)acrylic acid esters; 10-undecen-1-ol, 1-octene-3-ol, 2-methanol norbornene, hydroxystyrene, N-methylolacrylamide, glycerin monoallyl ether, allyl alcohol, allyloxyethanol, 2-butene-1,4-diol, and glycerin monoalcohol.

The hydroxyl-modified polyolefin (A) may be prepared, for example, by subjecting a composition containing an α-olefin having 2 to 20 carbon atoms and a hydroxyl-containing polymerizable monomer to a polymerization reaction, or by synthesizing a polymer of an α-olefin having 2 to 20 carbon atoms in advance and reacting the polymer with a hydroxyl-containing polymerizable monomer. Examples of the method for reacting a polymer of an α-olefin having 2 to 20 carbon atoms with a hydroxyl-containing polymerizable monomer include the following:
(1) A method in which a polymer of an α-olefin having 2 to 20 carbon atoms is dissolved in a solvent, a hydroxyl group-containing polymerizable monomer and a radical polymerization initiator are added, and the mixture is heated and stirred to react the polymer of an α-olefin having 2 to 20 carbon atoms with the hydroxyl group-containing polymerizable monomer.
(2) A method in which a polymer of an α-olefin having 2 to 20 carbon atoms is heated and melted, and then a hydroxyl group-containing polymerizable monomer and a radical polymerization initiator are added to the melt obtained by stirring, thereby reacting the polymer of an α-olefin having 2 to 20 carbon atoms with the hydroxyl group-containing polymerizable monomer.
(3) A method in which a polymer of an α-olefin having 2 to 20 carbon atoms is mixed with a hydroxyl group-containing polymerizable monomer and a radical polymerization initiator, and the resulting mixture is fed into an extruder and heated and kneaded while reacting the polymer of an α-olefin having 2 to 20 carbon atoms with the hydroxyl group-containing polymerizable monomer.
(4) A method in which a polymer of an α-olefin having 2 to 20 carbon atoms is immersed in a solution in which a hydroxyl group-containing polymerizable monomer and a radical polymerization initiator are dissolved in an organic solvent, and then the solution is heated to a temperature at which the polymer of the α-olefin having 2 to 20 carbon atoms does not dissolve, thereby reacting the polymer of the α-olefin having 2 to 20 carbon atoms with the hydroxyl group-containing polymerizable monomer.
etc.

The reaction temperature in the above (1) to (4) is, for example, 50°C or higher and 300°C or lower, and more preferably 80°C or higher and 300°C or lower. The reaction temperature in the above (1) to (4) is, for example, 1 minute to 10 hours. Reaction methods include batch and continuous methods, and the batch method is preferred to carry out the modification reaction uniformly.

Examples of radical polymerization initiators include organic peroxides such as dicumyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate)hexyne-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane;
organic peresters such as tert-butyl peracetate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl persec-octoate, tert-butyl perpivalate, cumyl perpivalate, tert-butyl perdiethyl acetate, and tert-butyl peroxybenzoate;
Examples of the initiator include azo compounds such as azobisisobutyronitrile and dimethylazoisobutyronitrile, and other initiators. The mixing ratio of the radical polymerization initiator is, for example, 0.001 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the polymer of the olefin having 2 to 20 carbon atoms.

In order to obtain good adhesion, the weight average molecular weight of the hydroxyl-modified polyolefin (A) used in the present invention is preferably 10,000 or more. In addition, in order to ensure appropriate fluidity, the weight average molecular weight of the hydroxyl-modified polyolefin (A) is preferably 500,000 or less. In the present invention, two or more types of hydroxyl-modified polyolefins (A) having different weight average molecular weights can be used in combination. In this case, it is preferable that the weight average molecular weight of all hydroxyl-modified polyolefins (A) is 10,000 or more and 500,000 or less, but hydroxyl-modified polyolefins (A) having a weight average molecular weight of less than 10,000 or more and more than 500,000 may be included. Of the hydroxyl-modified polyolefins (A) used in the adhesive of the present invention, those having a weight average molecular weight of 10,000 or more and 500,000 or less are preferably 50% by mass or more, more preferably 80% by mass or more, and more preferably 90% by mass or more.

In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values measured by gel permeation chromatography (GPC) under the following conditions:

Measuring device: Tosoh Corporation HLC-8320GPC
Column: TSKgel 4000HXL, TSKgel 3000HXL, TSKgel 2000HXL, TSKgel 1000HXL manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Data processing: Multistation GPC-8020 model II manufactured by Tosoh Corporation
Measurement conditions: Column temperature: 40°C
Solvent Tetrahydrofuran
Flow rate: 0.35 ml/min. Standard: Monodisperse polystyrene Sample: 100 μl of a tetrahydrofuran solution containing 0.2% by mass of resin solids filtered through a microfilter

The hydroxyl-modified polyolefin (A) used in the present invention is crystalline. In this specification, the presence or absence of crystallinity is judged based on the presence or absence of a melting point (peak) measured by the method described below.
The melting point of the hydroxyl-modified polyolefin (A) is preferably 40° C. or higher, more preferably 50° C. or higher, and even more preferably 60° C. or higher. The melting point of the hydroxyl-modified polyolefin (A) is preferably 100° C. or lower, more preferably 95° C. or lower, and even more preferably 90° C. or lower.

The melting point of the hydroxyl-modified polyolefin (A) is measured by DSC (differential scanning calorimetry). Specifically, the temperature is raised at 10°C/min from the cooling temperature to the heating temperature, then cooled at 10°C/min to the cooling temperature to remove the thermal history, and then heated again at 10°C/min to the heating temperature. The peak temperature at the second heating is taken as the melting point. The cooling temperature is set to a temperature 50°C or more lower than the crystallization temperature, and the heating temperature is set to a temperature 30°C or more higher than the melting point temperature. The cooling temperature and heating temperature are determined by trial measurements.

Two or more hydroxyl-modified polyolefins (A) having different melting points can be used in combination. In this case, it is preferable that all the hydroxyl-modified polyolefins (A) have melting points of 40°C or more and 100°C or less, but hydroxyl-modified polyolefins (A) having melting points less than 40°C or more and exceeding 100°C may be included. Of the hydroxyl-modified polyolefins (A) used in the adhesive of the present invention, those having melting points of 40°C or more and 100°C or less preferably account for 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

The hydroxyl-modified polyolefin (A) preferably has a heat of fusion of 0 J/g or more and 50 J/g or less. This allows for an adhesive with excellent adhesive strength, solvent resistance, and electrolyte resistance. The heat of fusion of the hydroxyl-modified polyolefin (A) can be measured by the method described in JIS-K-7122.

It is preferable to use a hydroxyl-modified polyolefin (A) having a heat of crystallization of 1 J/g or more, more preferably 10 J/g or more, and 100 J/g or less, more preferably 60 J/g or less. This makes it possible to provide a laminate that has excellent solvent resistance and electrolyte resistance and maintains adhesive strength even when used in applications that contain heat-generating contents or in environments where the surrounding temperature is likely to rise. The heat of crystallization can be measured by the method described in JIS-K-7122.

The hydroxyl value of the solid content of the hydroxyl-modified polyolefin (A) is preferably 0.1 mgKOH/g or more and 30 mgKOH/g or less. This allows the adhesive to have excellent adhesion, solvent resistance, electrolyte resistance, etc. The hydroxyl value of the hydroxyl-modified polyolefin (A) can be calculated, for example, from the weight average molecular weight of the hydroxyl-modified polyolefin (A) and the amount of added hydroxyl-containing polymerizable monomer.

(Acid Group-Modified Polyolefin (C))
The composition (X) may contain an acid group-modified polyolefin (C) in addition to the hydroxyl group-modified polyolefin (A). The acid group-modified polyolefin (C) is a resin in which a polymer of an α-olefin having 2 to 20 carbon atoms is modified with an acid group-containing polymerizable monomer.
The same materials as those exemplified as the raw material for the α-olefin hydroxyl group-modified polyolefin (A) having a carbon number of 2 to 20 can be used. It is preferable to use at least one selected from propylene and 1-butene, and it is preferable to include propylene and 1-butene.

The polymer of an α-olefin having 2 to 20 carbon atoms may be a homopolymer or a copolymer. The copolymer may be a block copolymer or a random copolymer. A copolymer of an α-olefin having 2 to 20 carbon atoms is preferable.
The polymer of an α-olefin having 2 to 20 carbon atoms may be prepared from a polymerizable monomer other than an α-olefin having 2 to 20 carbon atoms. The same materials as those exemplified as the raw materials for the hydroxyl group-modified polyolefin (A) can be used.

Examples of acid group-containing polymerizable monomers include acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, 1,2,3,4,5,8,9,10-octahydronaphthalene-2,3-dicarboxylic anhydride, 2-octa- Examples include 1,3-diketospiro[4.4]non-7-ene, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, methyl-norbornene-5-ene-2,3-dicarboxylic anhydride, and norborn-5-ene-2,3-dicarboxylic anhydride.

The synthesis method of the acid-modified polyolefin (C) is not particularly limited, and it can be synthesized by a conventionally known method. As an example, it can be synthesized by a method similar to that exemplified for the hydroxyl-modified polyolefin (A).

The weight average molecular weight of the acid group-modified polyolefin (C) is preferably 10,000 or more. In order to ensure appropriate fluidity, the weight average molecular weight of the acid group-containing polyolefin (C) is preferably 500,000 or less.

The acid-modified polyolefin (C) is preferably crystalline. The melting point of the acid-modified polyolefin (C) is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher. The melting point of the acid-modified polyolefin (C) is preferably 100°C or lower, more preferably 95°C or lower, and even more preferably 90°C or lower.

The acid-modified polyolefin (C) preferably has a heat of fusion of 0 J/g or more and 50 J/g or less. The acid-modified polyolefin (C) preferably has a heat of crystallization of 1 J/g or more, more preferably 10 J/g or more, and 100 J/g or less, more preferably 60 J/g or less.

The acid value of the acid-modified polyolefin (C) is preferably 0.1 mgKOH/g or more, since this provides good adhesion to metal substrates. On the other hand, although this depends on the structure of the olefin chain, if the acid value is high, the olefin chains tend to be difficult to crystallize due to the large number of crosslinking points in the cured coating film. Therefore, from the viewpoint of solvent resistance and electrolyte resistance, it is preferably 50 mgKOH/g or less. More preferably, it is 5 mgKOH/g or more and 40 mgKOH/g or less, and 5 mgKOH/g or more and 30 mgKOH/g or less.

The acid value of the acid group-modified polyolefin (C) can be calculated, for example, using an FT-IR (FT-IR4200, manufactured by JASCO Corporation) according to the following formula using the coefficient (f) obtained from a calibration curve prepared using a chloroform solution of maleic anhydride, the absorbance (I) of the stretching peak (1780 cm ^- 1) of the anhydride ring of maleic anhydride in the maleic anhydride-modified polyolefin solution, and the absorbance (II) of the stretching peak (1720 cm ^-1 ) of the carbonyl group of maleic acid, where the molecular weight of maleic anhydride is 98.06 and the molecular weight of potassium hydroxide is 56.11.

When composition (X) contains acid-modified polyolefin (C), its amount can be adjusted as appropriate. The content of acid-modified polyolefin (C) in the total solid content of hydroxyl-modified polyolefin (A) and acid-modified polyolefin (C) is, for example, 90 mass% or less, in another embodiment 15 mass% or less, in another embodiment 10 mass% or less, and in another embodiment 5 mass% or less. This makes it possible to obtain an adhesive with excellent adhesion and storage stability.

(Polyolefin (D))
The composition (X) may contain a polyolefin (D) having no reactive functional group in addition to the hydroxyl group-modified polyolefin (A). The polyolefin (D) is preferably a crystalline olefin resin. When the polyolefin (D) is a crystalline olefin resin, the polarity of the cured coating film of the adhesive is reduced, and the resistance to the electrolyte is improved.

Examples of polyolefins (D) include homopolymers and copolymers of olefins having 2 to 8 carbon atoms, such as ethylene, propylene, isobutylene, 1-butene, 4-methyl-1-pentene, hexene, and vinylcyclohexane, as well as copolymers of olefins having 2 to 8 carbon atoms with other monomers. Specific examples include polyethylenes such as high density polyethylene (HDPE), low density polyethylene (LDPE), and linear low density polyethylene resins, polypropylene, polyisobutylene, poly(1-butene), poly(4-methyl-1-pentene), polyvinylcyclohexane, α-olefin copolymers such as ethylene-propylene block copolymers, ethylene-propylene random copolymers, ethylene-1-butene copolymers, ethylene-4-methyl-1-pentene copolymers, and ethylene-hexene copolymers, ethylene-methyl methacrylate copolymers, and propylene-1-butene copolymers. Among these, homopolymers of olefins having 3 to 8 carbon atoms and copolymers of two or more types of olefins having 3 to 8 carbon atoms are preferred because they provide particularly good adhesive strength, and homopolymers or copolymers of propylene are more preferred, with propylene homopolymers being even more preferred.

Polyolefin (D) has high solubility in solvents and improves coatability, so it is preferable that the weight average molecular weight is 2000 to 300,000. The weight average molecular weight of polyolefin (D) is more preferably 20,000 to 250,000, and even more preferably 40,000 to 250,000.

Two or more polyolefins (D) having different weight average molecular weights can be used in combination. In this case, it is preferable that the weight average molecular weight of all polyolefins (D) is 2,000 or more and 300,000 or less, but polyolefins (D) having a weight average molecular weight of less than 2,000 or more and exceeding 300,000 may be included. When polyolefins (D) are used, it is preferable that those having a weight average molecular weight of 2,000 or more and 300,000 or less account for 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

The melting point of polyolefin (D) is preferably 50°C to 100°C. A melting point of 50°C or higher can more reliably improve electrolytic resistance, while a melting point of 100°C or lower can maintain good coatability. The melting point of polyolefin (D) is more preferably 50°C to 95°C, and even more preferably 60°C to 90°C.

Two or more polyolefins (D) having different melting points can also be used in combination. In this case, it is preferable that all polyolefins (D) have melting points of 50°C or more and 100°C or less, but polyolefins (D) having melting points less than 50°C or more and exceeding 100°C may be included. Of the polyolefins (D), those having melting points of 50°C or more and 100°C or less preferably account for 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

When composition (X) contains polyolefin (D), its amount can be adjusted as appropriate. The mass ratio (A):(D) of the hydroxyl-modified polyolefin (A) to the polyolefin (D) is, for example, 100:0 to 10:90, in another embodiment, 100:1 to 15:85, and in another embodiment, 75:25 to 15:85. This makes it possible to obtain an adhesive that has excellent storage stability in addition to solvent resistance and electrolyte resistance.

(Composition (Y))
(Polyisocyanate Compound (B))
The composition (Y) contains a polyisocyanate compound (B). As the polyisocyanate compound (B), a conventionally known compound can be used, for example, aromatic diisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, and 1,5-naphthalene diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate, and hydrogenated diphenylmethane diisocyanates. Examples of the diisocyanate include isocyanates, alicyclic diisocyanates such as hydrogenated xylylene diisocyanate, and aliphatic diisocyanates such as pentamethylene diisocyanate and hexamethylene diisocyanate, and compounds derived therefrom, that is, isocyanurates, adducts, biuret types, uretdione types, allophanate types, prepolymers having an isocyanate residue (low polymers obtained from diisocyanates and polyols), and complexes thereof.

As the polyisocyanate compound (B), a compound obtained by reacting some of the isocyanate groups of the polyfunctional isocyanate compound described above with a compound reactive with the isocyanate groups may be used. Examples of compounds reactive with isocyanate groups include 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-ethylhexyl alcohol, 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 glycidyl ether, and cyclohexanedimethanol diglycidyl ether; and compounds containing carboxylic acids such as acetic acid, butanoic acid, hexanoic acid, octanoic acid, succinic acid, adipic acid, sebacic acid, and phthalic acid.

The polyisocyanate compound (B) preferably contains at least one selected from an aliphatic polyisocyanate and an alicyclic polyisocyanate. The content of the aliphatic polyisocyanate and/or the alicyclic polyisocyanate in the polyisocyanate compound (B) is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 95% by mass or more. The entire amount of the polyisocyanate compound (B) may be an aliphatic polyisocyanate and/or an alicyclic polyisocyanate.

The polyisocyanate compound (B) may be a mixture of at least one selected from a derivative of an aliphatic diisocyanate and/or an alicyclic diisocyanate (isocyanurate, adduct, biuret, uretdione, allophanate, prepolymer having an isocyanate residue) and an aliphatic diisocyanate and/or an alicyclic diisocyanate. In this case, the content of the aliphatic diisocyanate and/or the alicyclic diisocyanate is 0.0.1% by mass or more and 1% by mass or less.

It is preferable that composition (X) and composition (Y) are used in such a range that the ratio of the number of moles of isocyanate groups [NCO] contained in composition (Y) to the number of moles of hydroxyl groups [OH] contained in composition (X), [NCO]/[OH], is 0.5 or more and 5.0 or less.

(Additive (E))
The adhesive of the present invention may contain an additive (E). As the additive (E), various additives such as a silane coupling agent (E-1), a urethane catalyst (E-2), a tackifier (E-3), a thermoplastic elastomer (E-4), an epoxy resin (E-5), a monomer having a functional group reactive with isocyanate (E-6), an acid anhydride, a plasticizer, a phosphoric acid compound, a reactive elastomer, etc. can be used. The content of these additives (E) may be appropriately adjusted within a range that does not impair the function of the adhesive of the present invention.

Examples of silane coupling agents (E-1) include aminosilanes such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane, and N-phenyl-γ-aminopropyltrimethoxysilane; epoxysilanes such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane; vinylsilanes such as vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrimethoxysilane, and γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane, γ-mercaptopropyltrimethoxysilane, and the like.

As the urethane catalyst (E-2), metal catalysts, amine catalysts, aliphatic cyclic amide compounds, titanium chelate complexes, organophosphorus compounds, and other catalysts can be used.

Metal catalysts include metal complexes, inorganic metals, and organic metals. Specific examples of metal complexes include acetylacetonate salts of metals selected from the group consisting of Fe (iron), Mn (manganese), Cu (copper), Zr (zirconium), Th (thorium), Ti (titanium), Al (aluminum), and Co (cobalt). Examples include iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, and zirconia acetylacetonate. Of these, iron acetylacetonate (Fe(acac)3) or manganese acetylacetonate (Mn(acac)2) are preferred in terms of toxicity and catalytic activity.

Examples of inorganic metal catalysts include catalysts selected from Fe, Mn, Cu, Zr, Th, Ti, Al, Co, etc.

Examples of organometallic catalysts include stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dioctyltin dilaurate, nickel octylate, nickel naphthenate, cobalt octylate, cobalt naphthenate, bismuth octylate, and bismuth naphthenate. Among these, preferred compounds are organotin catalysts, and more preferred are stannous dioctoate and dibutyltin dilaurate.

Amine catalysts include triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methylquinuclidine, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropylenediamine, N,N,N',N",N"-pentamethyldiethylenetriamine, N,N,N',N",N"-pentamethyl-(3-aminopropyl)ethylenediamine, N,N,N',N",N"-pentamethyldipropylenetriamine, N,N,N',N'-tetramethyl n-hexamethylenediamine, bis(2-dimethylaminoethyl)ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethanol, N,N-dimethyl-N'-(2-hydroxyethyl)ethylenediamine, N,N-dimethyl-N'-(2-hydroxyethyl)propanediamine, bis(dimethylaminopropyl)amine, bis(dimethylaminopropyl)isopropanolamine, 3-quinuclidinol, N,N,N',N'-tetramethylguanidine , 1,3,5-tris(N,N-dimethylaminopropyl)hexahydro-S-triazine, 1,8-diazabicyclo[5.4.0]undecene-7, 1,5-diazabicyclo[4.3.0]nonene-5, N-methyl-N'-(2-dimethylaminoethyl)piperazine, N,N'-dimethylpiperazine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethyl Examples of tertiary amines include tertiary amines such as 1-(2-hydroxyethyl)imidazole, N,N-dimethylhexanolamine, N-methyl-N'-(2-hydroxyethyl)piperazine, 1-(2-hydroxyethyl)imidazole, 1-(2-hydroxypropyl)imidazole, 1-(2-hydroxyethyl)-2-methylimidazole, and amine salts of these tertiary amines with phenol, octylic acid, quaternized tetraphenylborate salts, etc.

Examples of aliphatic cyclic amide compounds include δ-valerolactam, ε-caprolactam, ω-enantholactam, η-capryllactam, and β-propiolactam. Among these, ε-caprolactam is preferred because of its excellent curing acceleration effect.

Titanium chelate complexes are compounds whose catalytic activity is enhanced by exposure to ultraviolet light, and titanium chelate complexes having an aliphatic or aromatic diketone as a ligand are preferred because of their excellent curing acceleration effect. In addition, in the present invention, those having an alcohol with 2 to 10 carbon atoms as a ligand in addition to an aromatic or aliphatic diketone are preferred because the effects of the present invention are more pronounced.

When the composition (X) contains an acid group-modified polyolefin (C), it is also preferable to use an organic phosphorus compound such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tris(4-methylphenyl)phosphine, tris(4-butylphenyl)phosphine, diphenylphosphine, or phenylphosphine in addition to the urethane catalyst (E-2).

Examples of tackifiers (E-3) include rosin-based or rosin ester-based tackifiers, terpene-based or terpene phenol-based tackifiers, saturated hydrocarbon resins, coumarone-based tackifiers, coumarone-indene-based tackifiers, styrene resin-based tackifiers, xylene resin-based tackifiers, phenol resin-based tackifiers, and petroleum resin-based tackifiers. These may be used alone or in combination of two or more.

As the thermoplastic elastomer (E-4), for example, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, styrene-ethylene-propylene copolymer, styrene-isoprene-styrene copolymer, styrene-ethylene-(ethylene-propylene)-styrene copolymer, styrene-isobutylene-styrene copolymer, and modified products thereof, hydrogenated products, graft copolymers having a styrene structure in the side chain, core-shell type multi-layer structure rubber having a styrene structure in the shell, etc. can be suitably used, and a blend of two or more types may also be used. Among them, styrene-ethylene-butylene-styrene copolymer, styrene-ethylene-propylene-styrene copolymer, styrene-ethylene-(ethylene-propylene)-styrene copolymer, etc. can be mentioned.

The thermoplastic elastomer (E-4) may have a reactive functional group. Examples of such functional groups include hydroxyl groups, carboxyl groups, carbonyl groups, thiocarbonyl groups, acid halide groups, acid anhydride groups, thiocarboxylic acid groups, aldehyde groups, thioaldehyde groups, carboxylate groups, amide groups, sulfonic acid groups, sulfonate groups, phosphoric acid groups, phosphoric acid ester groups, amino groups, imino groups, nitrile groups, pyridyl groups, quinoline groups, epoxy groups, thioepoxy groups, sulfide groups, isocyanate groups, isothiocyanate groups, silicon halide groups, alkoxy silicon groups, tin halide groups, boronic acid groups, boron-containing groups, boronate salt groups, alkoxy tin groups, and phenyl tin groups.

Epoxy resins (E-5) include bisphenol type epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins; biphenyl type epoxy resins such as biphenyl type epoxy resins and tetramethylbiphenyl type epoxy resins; dicyclopentadiene-phenol addition reaction type epoxy resins, etc. It is preferable to use epoxy resins (E-5) with a number average molecular weight (Mn) of 300 to 2,000. It is also preferable to use epoxy resins with an epoxy equivalent of 150 to 1,000 g/equivalent.

Examples of the monomer (E-6) having a functional group reactive with isocyanate include hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, glycerin mono(meth)acrylate, pentaerythritol mono(meth)acrylate, trimethylolpropane mono(meth)acrylate, tetramethylolethane mono(meth)acrylate, butanediol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, 2-(6-hydrohexanoyloxy)ethyl acrylate, and 2-(meth)acryloyloxyethyl acid phosphate; 10-undecene-1-ol, 1-octen-3-ol, 2-methanol norbornene, hydroxystyrene, and N-methylol a Monomers having a hydroxyl group such as acrylamide, glycerin monoallyl ether, allyl alcohol, allyloxyethanol, 2-butene-1,4-diol, and glycerin monoalcohol, acrylic acid, methacrylic acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, maleic anhydride, 4-methylcyclohex-4-ene-1,2-dicarboxylic anhydride, bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, 1,2,3,4,5,8,9,10-octahydro Examples of monomers having an acid group include 2-octa-1,3-diketospiro[4.4]non-7-ene, bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, maleopimaric acid, tetrahydrophthalic anhydride, methyl-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride, methyl-norbornene-5-ene-2,3-dicarboxylic anhydride, and norborn-5-ene-2,3-dicarboxylic anhydride. The content of the monomer (E-6) having a functional group reactive with isocyanate is, for example, 5% by mass or less of the solid content of the composition (X).

Examples of acid anhydrides include cyclic aliphatic acid anhydrides, aromatic acid anhydrides, and unsaturated carboxylic acid anhydrides, and these may be used alone or in combination of two or more. More specifically, for example, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic acid anhydride, dodecenylsuccinic anhydride, polyadipic anhydride, polyazelaic anhydride, polysebacic anhydride, poly(ethyloctadecanedioic acid) anhydride, poly(phenylhexadecanedioic acid) anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methylhimic anhydride, trialkyltetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhimic anhydride, trialkyltetrahydrophthalic anhydride, methylhexa ... Examples of such anhydrides include ethylcyclohexene dicarboxylic anhydride, methylcyclohexene tetracarboxylic anhydride, ethylene glycol bistrimellitate dianhydride, HET anhydride, Nadic anhydride, methylnadic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexane-1,2-dicarboxylic anhydride, 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride, and 1-methyl-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride.

The above-mentioned compounds may also be modified with glycols as acid anhydrides. Examples of glycols that can be used for modification include alkylene glycols such as ethylene glycol, propylene glycol, and neopentyl glycol; and polyether glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Furthermore, copolymer polyether glycols of two or more of these glycols and/or polyether glycols may also be used.

The amount of acid anhydride blended is preferably 0.01 parts by mass or more, and more preferably 0.8 parts by mass or more, per 100 parts by mass of resin (A). The amount of acid anhydride blended is preferably 10 parts by mass or less, and more preferably 8 parts by mass or less, and even more preferably 1.5 parts by mass or less, per 100 parts by mass of resin (A). This improves the adhesion between the adhesive and the metal, and makes it possible to obtain an adhesive with excellent initial adhesive strength and adhesive strength after heat sealing.

The reason why the use of acid anhydrides gives adhesives superior adhesion and heat resistance is unclear, but it is speculated as follows. Acid anhydrides have polar groups and have excellent affinity for metal substrates. In addition, because they have a relatively small molecular weight, they are relatively easy to move. It is thought that the applied adhesive migrates to the metal substrate before it completely hardens, and acts like an anchor agent, thereby contributing to improved adhesion and heat resistance.

Examples of plasticizers include polyisoprene, polybutene, and procell oil. Examples of thermoplastic elastomers include styrene-butadiene copolymer (SBS), hydrogenated styrene-butadiene copolymer (SEBS), SBBS, hydrogenated styrene-isoprene copolymer (SEPS), styrene block copolymer (TPS), and olefin elastomer (TPO). Examples of reactive elastomers include acid-modified versions of these elastomers.

Examples of phosphoric acid compounds include phosphoric acids such as hypophosphorous acid, phosphorous acid, orthophosphoric acid, and hypophosphoric acid; condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and ultraphosphoric acid; monomethyl orthophosphate, monoethyl orthophosphate, monopropyl orthophosphate, monobutyl orthophosphate, mono-2-ethylhexyl orthophosphate, monophenyl orthophosphate, monomethyl phosphite, monoethyl phosphite, monopropyl phosphite, monobutyl phosphite, mono-2-ethylhexyl phosphite, monophenyl phosphite, and o Examples include mono- and diesters of di-2-ethylhexyl orthophosphate, diphenyl orthophosphate, dimethyl phosphite, diethyl phosphite, dipropyl phosphite, dibutyl phosphite, di-2-ethylhexyl phosphite, diphenyl phosphite, etc., mono- and diesters of condensed phosphoric acid and alcohols, for example, products obtained by adding epoxy compounds such as ethylene oxide and propylene oxide to the above phosphoric acids, and epoxy phosphoric acid esters obtained by adding the above phosphoric acids to aliphatic or aromatic diglycidyl ethers.

(Organic solvent)
The adhesive of the present invention can ensure flowability and exhibit appropriate coatability by further blending an organic solvent in addition to the above-mentioned components. Such organic solvents are not particularly limited as long as they can be removed by volatilization by overheating in the drying step when the adhesive is applied. Examples of such organic solvents include aromatic organic solvents such as toluene and xylene; aliphatic organic solvents such as n-hexane and n-heptane; alicyclic organic solvents such as cyclohexane and methylcyclohexane; halogen-based organic solvents such as trichloroethylene, dichloroethylene, chlorobenzene and chloroform; ketone-based solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ester-based solvents such as ethyl acetate and butyl acetate; ether-based solvents such as diisopropyl ether, butyl cellosolve, tetrahydrofuran, dioxane and butyl carbitol; glycol ether-based solvents such as diethylene glycol monomethyl ether, triethylene glycol monomethyl ether and propylene glycol monomethyl ether; and glycol ester-based solvents such as ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate and diethylene glycol monoethyl ether acetate. These may be used alone or in combination of two or more.

Since this provides an adhesive with excellent solubility of the hydroxyl-modified polyolefin (A) and excellent coating suitability, it is preferable to use a mixed solvent of at least one selected from alicyclic organic solvents and aromatic organic solvents and at least one selected from ester solvents and ketone solvents. The amount of these solvents is appropriately adjusted according to the desired balance between the solubility of the hydroxyl-modified polyolefin (A) and the coating suitability. It is preferable to use methylcyclohexane as the alicyclic organic solvent, and it is preferable to use toluene as the aromatic organic solvent. It is preferable to use ethyl acetate as the ester solvent, and it is preferable to use methyl ethyl ketone as the ketone solvent.

The amount of organic solvent used is preferably such that the solid content of composition (X) is 5 to 30 mass %. Also, it is preferably such that the solid content of composition (Y) is 10 to 100 mass %. This allows for an adhesive with excellent coatability and wettability to metal films.

The adhesive of the present invention has excellent adhesion and heat resistance between non-polar substrates such as olefin resins and metal substrates.

<Laminate>
The laminate of the present invention includes a first substrate, a second substrate, and an adhesive layer disposed between the first substrate and the second substrate and bonding the first substrate and the second substrate. The adhesive layer is a cured coating of the adhesive described above. In addition to the first substrate and the second substrate, the laminate may further include another substrate. The adhesive layer bonding the first substrate and the other substrate, and the second substrate and the other substrate may or may not be a cured coating of the adhesive of the present invention.

Examples of the first substrate, second substrate, and other substrates that can be used include paper, olefin resins, acrylonitrile-butadiene-styrene copolymers (ABS resins), polyvinyl chloride resins, fluorine resins, poly(meth)acrylic resins, carbonate resins, polyamide resins, polyimide resins, polyphenylene ether resins, polyphenylene sulfide resins, and synthetic resin films made from polyester resins, and metal foils such as copper foil and aluminum foil.

The adhesive of the present invention has excellent adhesion between non-polar substrates such as olefin resins and metal substrates, so it is preferable that one of the first substrate and the second substrate is a non-polar substrate and the other is a metal substrate, but this is not limited thereto.

The laminate of the present invention is obtained by applying the adhesive of the present invention to one of a first substrate and a second substrate, laminating the other substrate, and curing the adhesive. After applying the adhesive, it is preferable to provide a drying step before laminating the first substrate and the second substrate.
The adhesive can be applied by a gravure coater, microgravure coater, reverse coater, bar coater, roll coater, die coater, etc. The amount of adhesive applied is preferably adjusted so that the applied weight after drying is 0.5 to 20.0 g/ ^m2 . If the amount is less than 0.5 g/ ^m2 , the continuous uniform application is likely to decrease, and if the amount is more than 20.0 g/ ^m2 , the solvent removal after application is also likely to decrease, leading to decreased workability and problems with residual solvent.

When laminating the first substrate and the second substrate, the temperature of the laminating roll is preferably 25 to 120° C., and the pressure is preferably 3 to 300 kg/cm ² .
After the first substrate and the second substrate are bonded together, an aging step is preferably performed, preferably at 25 to 100° C. for 12 to 240 hours.

In particular, the adhesive of the present invention exhibits good initial adhesive strength and solvent resistance even when aged at relatively low temperatures of 60°C or less, and even 55°C or less. When aging is performed at 60°C or less, the aging time is preferably 72 hours or more. There is no particular upper limit to the aging time, but a sufficient effect is achieved at about 168 hours. From the viewpoint of the balance between the aging temperature and the aging time, it is preferable to perform the aging process at 40 to 60°C for 24 to 168 hours.

<Battery packaging material>
The battery packaging material of the present invention includes, as an example, a first substrate, a second substrate, a third substrate, a first adhesive layer for bonding the first substrate and the second substrate, and a second adhesive layer for bonding the second substrate and the third substrate. The first substrate is a polyolefin film, and the second substrate is a metal foil. The third substrate is a resin film such as nylon or polyester. The first adhesive layer is a cured coating film of the adhesive of the present invention. The second adhesive layer may or may not be a cured coating film of the adhesive of the present invention. On the opposite side of the third substrate to the side on which the second adhesive layer is provided, another substrate may be disposed with or without an adhesive layer, or a coating layer may be provided. Other substrates or coating layers may not be provided.

The polyolefin film may be appropriately selected from conventionally known olefin resins. For example, polyethylene, polypropylene, ethylene-propylene copolymer, etc. may be used, but are not particularly limited thereto. A non-stretched film is preferable. The thickness of the polyolefin film is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 25 μm or more. In addition, it is preferably 100 μm or less, more preferably 95 μm or less, and even more preferably 90 μm or less.
The first base material functions as a sealant layer when pieces of the battery packaging material of the present invention are heat-sealed and bonded together during the production of a battery, which will be described later.

Metal foils include aluminum, copper, nickel, etc. These metal foils may be subjected to surface treatments such as sandblasting, polishing, degreasing, etching, surface treatment by immersion or spraying with an anti-rust agent, trivalent chromium conversion treatment, phosphate conversion treatment, sulfide conversion treatment, anodized film formation, and fluororesin coating. Among these, those subjected to trivalent chromium conversion treatment are preferred from the viewpoints of excellent adhesion retention performance (resistance to environmental deterioration) and corrosion resistance. In addition, the thickness of this metal film is preferably in the range of 10 to 100 μm from the viewpoint of corrosion prevention.

Examples of resin films that can be used as the third substrate include resin films of polyester resin, polyamide resin, epoxy resin, acrylic resin, fluororesin, polyurethane resin, silicone resin, phenol resin, and mixtures and copolymers thereof. Among these, polyester resin and polyamide resin are preferred, and biaxially oriented polyester resin and biaxially oriented polyamide resin are more preferred. Specific examples of polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymer polyester, polycarbonate, etc. Specific examples of polyamide resin include nylon 6, nylon 6,6, copolymer of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), etc.

The coating layer can be formed from, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, etc. It is preferable to form it from a two-component curing resin. Examples of the two-component curing resin that forms the coating layer include two-component curing urethane resin, two-component curing polyester resin, and two-component curing epoxy resin. In addition, a matting agent may be blended into the coating layer.

Examples of matting agents include fine particles with a particle size of about 0.5 nm to 5 μm. The material of the matting agent is not particularly limited, but examples include metals, metal oxides, inorganic substances, and organic substances. The shape of the matting agent is also not particularly limited, but examples include spherical, fibrous, plate-like, amorphous, and balloon-like. Specific examples of matting agents include talc, silica, graphite, kaolin, montmorillonite, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, carbon black, carbon nanotubes, high melting point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. These matting agents may be used alone or in combination of two or more. Among these matting agents, silica, barium sulfate, and titanium oxide are preferred from the viewpoints of dispersion stability, cost, and the like. In addition, the matting agent may be subjected to various surface treatments such as insulation treatment and high dispersibility treatment.

When such a laminate is made into a battery, it is molded so that the polyolefin film, which is the first substrate, is located inside the third substrate, resulting in the secondary battery exterior material of the present invention. There are no particular limitations on the molding method, and the following method is one example.

- Hot and compressed air molding method: A method in which battery packaging material is sandwiched between a lower mold with holes through which high-temperature, high-pressure air is supplied and an upper mold with pocket-shaped recesses, and the recesses are formed by supplying air while heating and softening the material.
Preheater flat plate compressed air molding method: This method involves heating and softening the battery packaging material, then sandwiching it between a lower mold with holes through which high-pressure air is supplied and an upper mold with pocket-shaped recesses, and supplying air to form the recesses.
Drum vacuum molding method: A method in which battery packaging material is partially heated and softened in a heating drum, and then the pocket-shaped recesses of a drum are vacuumed to form the recesses.
・Pin molding method: A method in which the base sheet is heated and softened, and then compressed using a pocket-shaped, concave-convex mold.
Pre-heater plug-assisted compressed air molding method: This method involves heating and softening battery packaging material, then sandwiching it between a lower mold having a hole through which high-pressure air is supplied and an upper mold having a pocket-shaped recess, and supplying air to form the recess. During molding, a convex plug is raised and lowered to assist the molding.

The preheater plug assisted compressed air molding method, which is a heating vacuum molding method, is preferred because the thickness of the base material after molding is uniform.
The battery packaging material of the present invention thus obtained can be suitably used as a battery container for hermetically housing battery elements such as a positive electrode, a negative electrode, and an electrolyte.

<Batteries>
The battery of the present invention can be obtained by covering a battery element including a positive electrode, a negative electrode, and an electrolyte with the battery packaging material of the present invention in such a manner that a flange portion (a region where the sealant layers come into contact with each other) is formed around the periphery of the battery element, with metal terminals connected to each of the positive electrode and negative electrode protruding outward, and then heat-sealing the sealant layers of the flange portion to form a hermetic seal.

The battery obtained using the battery packaging material of the present invention may be either a primary battery or a secondary battery, but is preferably a secondary battery. There are no particular limitations on the secondary battery, and examples include lithium ion batteries, lithium ion polymer batteries, lead acid batteries, nickel-hydrogen batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, condensers, and capacitors. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications of the battery packaging material of the present invention.

The present invention will be explained below using examples and comparative examples, but the present invention is not limited to these. The compounding composition and other numerical values are based on mass unless otherwise specified.

<Adjustment of adhesive>
Example 1
The adhesive of Example 1 was prepared by thoroughly stirring 100 parts of hydroxyl-modified polyolefin (A-2), 3.8 parts of polyisocyanate compound (B-2), and 40 parts of toluene.

(Examples 2 to 4)
Adhesives of Examples 2 to 4 were prepared in the same manner as in Example 1, except that the formulations were changed as shown in Table 1.
(Comparative Examples 1 to 4)
Adhesives of Comparative Examples 1 to 4 were prepared in the same manner as in Example 1, except that the formulations were changed as shown in Table 2.

The details of the compounds used in the examples and comparative examples are as follows: The solid content of ε-caprolactam and triphenylphosphine is 100%.
Hydroxyl-modified polyolefin (A-1): Hydroxyl-modified copolymer of an α-olefin having 2 to 20 carbon atoms, crystalline (melting point 73°C, heat of fusion 38 J/g, heat of crystallization 35 J/g), weight average molecular weight 181,700, hydroxyl value in solution state 1.28 mgKOH/g (5.06 mgKOH/g in terms of solid content), solid content 25.3%.
Hydroxyl-modified polyolefin (A-2): Hydroxyl-modified copolymer of an α-olefin having 2 to 20 carbon atoms, crystalline (melting point 74°C, heat of fusion 36 J/g, heat of crystallization 31 J/g), weight average molecular weight 202,400, hydroxyl value in solution state 5.25 mgKOH/g (20.75 mgKOH/g in terms of solid content), solid content 25.3%.
Hydroxyl-modified polyolefin (A-3): Hydroxyl-modified copolymer of α-olefin having 2 to 20 carbon atoms, crystalline (melting point 96°C, heat of fusion 45 J/g, heat of crystallization 2 J/g), weight average molecular weight 172,000, hydroxyl value in solution state 4.16 mgKOH/g (hydroxyl value of solid content 20.8 mgKOH/g), solid content 20%.
HARDLEN N2002: Acid group modified olefin resin, crystalline, solids content 20%.
Unistol P-901: Hydroxyl-modified olefin resin, non-crystalline, hydroxyl value in solution state is 11.0 mg KOH/g (50.0 mg KOH/g in terms of solid content), solid content is 22%.
Unistol P-902: Acid group modified olefin resin, non-crystalline, solids content is 22%.
Unistol P-802: Acid-modified olefin, solids content 22%.
Polyisocyanate compound (B-1): nurate form of hexamethylene diisocyanate, NCO% 21.8%, solid content 100%.
Polyisocyanate compound (B-2): Biuret form of hexamethylene diisocyanate, NCO% 20.7%, solid content 90%.
Denacol EX-321L: manufactured by Nagase ChemteX Corporation, trimethylolpropane polyglycidyl ether type epoxy resin, epoxy equivalent 130, solid content 100%.

The presence or absence of crystallinity of the hydroxyl-modified polyolefin (A) used in the examples and comparative examples was determined by DSC (differential scanning calorimetry) by heating from -50°C to 200°C at 10°C/min, cooling to -50°C at 10°C/min to remove the thermal history, and then heating again to 200°C at 10°C/min, and determining whether a peak was observed during the second heating.

<Laminate>
Example 1
The adhesive of Example 1 was applied to the glossy surface of a chromate-treated aluminum foil (film thickness: 40 μm) with a bar coater at a coating amount of 4 g/m ² (dry), dried at 80° C. for 1 minute, and then laminated to an unstretched polyolefin film (film thickness: 40 μm) at 100° C. Next, an adhesive was applied to the matte surface of the aluminum foil with a coating amount of 4 g/m 2 (dry) with a bar coater, the adhesive being a base agent "Dick Dry LX-906" (manufactured by DIC Corporation) and a hardener "KW- ⁷⁵ " (manufactured by DIC Corporation) mixed so that the weight ratio of base agent/hardener was 100/10, and then a stretched polyamide film having a thickness of 25 μm was laminated thereon. Then, the laminate was aged at 40° C. for 5 days to obtain the laminate of Example 1.

(Examples 2 to 4)
An adhesive was prepared and a laminate was obtained in the same manner as in Example 1, except that the adhesive used for bonding the aluminum foil and the unstretched polyolefin film was changed.

(Comparative Examples 1 to 4)
An adhesive was prepared and a laminate was obtained in the same manner as in Example 1, except that the adhesive used for bonding the aluminum foil and the unstretched polyolefin film was changed.

<Evaluation>
(Measurement of initial adhesive strength)
Using an Autograph AGS-J made by Shimadzu Corporation, the adhesive strength between the aluminum foil and the unstretched polyolefin film of the laminate was evaluated under the conditions of a peel speed of 50 mm/min, a peel width of 15 mm, and a peel shape of 180°. The unit is N/15 mm.

(Solvent resistance (wet))
The aged laminate was immersed in 30 g of a mixed solvent of ethylene carbonate/dimethyl carbonate/ethyl methyl carbonate = 1/1/1 for 1 day at 50 ° C. The laminate was removed and before the solvent dried, the adhesive strength between the aluminum foil and the unstretched polyolefin film of the laminate was measured under the conditions of a peel speed of 50 mm / min, a peel width of 15 mm, and a peel shape of 180 °. The unit is N / 15 mm.

As is clear from Tables 1 and 2, the adhesive of the present invention has better initial adhesive strength and solvent resistance than the adhesive of the comparative example.

The adhesive of the present invention has excellent adhesion and heat resistance between non-polar substrates such as olefin resins and metal substrates, and laminates obtained using the adhesive of the present invention can be suitably used, for example, as packaging materials for batteries. Furthermore, the applications of the adhesive of the present invention are not limited to battery packaging materials and laminates therefor, but can be widely used in fields requiring adhesion between non-polar substrates and metal substrates, such as outer panels for home appliances, furniture materials, and building interior components.

Claims (19)

A two-component curing adhesive for lithium-ion battery exterior materials, comprising a composition (X) containing a hydroxyl-modified polyolefin (A) and a composition (Y) containing a polyisocyanate compound (B), wherein the hydroxyl-modified polyolefin (A) is crystalline and is a polymer of an α-olefin having 2 to 20 carbon atoms. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the solid content hydroxyl value of the hydroxyl-modified polyolefin (A) is 0.1 mg KOH/g or more and 30 mg KOH/g or less. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the melting point of the hydroxyl-modified polyolefin (A) is 40°C or higher and 100°C or lower. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the heat of fusion of the hydroxyl-modified polyolefin (A) is 0 J/g or more and 50 J/g or less. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the weight average molecular weight of the hydroxyl-modified polyolefin (A) is 10,000 or more and 500,000 or less. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the hydroxyl-modified polyolefin resin (A) contains structural units derived from propylene. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the hydroxyl-modified polyolefin resin (A) contains a structural unit derived from 1-butene. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the polyisocyanate compound (B) contains at least one selected from aliphatic polyisocyanates and alicyclic polyisocyanates. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the content of at least one selected from the group consisting of aliphatic polyisocyanates and alicyclic polyisocyanates in the polyisocyanate compound (B) is 50 mass% or more. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, wherein the molar ratio [NCO]/[OH] of the isocyanate groups contained in the composition (Y) to the hydroxyl groups contained in the composition (X) is 0.5 or more and 5.0 or less. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, which contains an acid-modified polyolefin (C). The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, which contains a polyolefin (D) that does not have a reactive functional group. The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, which contains a silane coupling agent (E-1). The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, which contains a urethane catalyst (E-2). The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, which contains a tackifier (E-3). The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, which contains a thermoplastic elastomer (E-4). The two-component curing adhesive for lithium-ion battery exterior materials according to claim 1, which contains an epoxy resin (E-5). A laminate for use as an exterior material for lithium-ion batteries, comprising a first substrate, a second substrate, and an adhesive layer for bonding the first substrate and the second substrate, the adhesive layer being a cured coating of the two-component curing adhesive according to any one of claims 1 to 17. A packaging material for lithium ion batteries formed by molding the laminate according to claim 18.