JP2020105294A - Polyurethane polyol and adhesive composition - Google Patents

Abstract

To obtain an adhesive which has excellent adhesive strength between a metal foil and a resin film and has electrolyte resistance and heat resistance.SOLUTION: A polyurethane polyol has: a polyol-derived structural unit containing at least one of a structural unit derived from a polyolefin polyol (a1) and a structural unit derived from a polyester polyol (a2); a structural unit derived from a polyisocyanate (b); and two or more hydroxyl groups. The polyolefin polyol (a1) contains no alicyclic structure. The polyester polyol (a2) has a structural unit derived from a hydrogenated dimer acid and a structural unit derived from a hydrogenated dimer diol. The polyisocyanate (b) has a saturated crosslinked alicyclic structure.SELECTED DRAWING: None

Description

The present invention relates to a polyurethane polyol and an adhesive composition, and more particularly to a polyurethane polyol having a structural unit derived from a polyol and a structural unit derived from a polyisocyanate, and an adhesive composition containing the polyurethane polyol.

2. Description of the Related Art In recent years, lithium-ion secondary batteries have become widespread as power sources for electronic devices such as laptop computers and mobile phones, and transportation equipment such as automobiles. There is an increasing demand for miniaturization, weight reduction, and thinning of these devices. In order to meet these demands, a small, lightweight, and large capacity secondary battery is required.

In a general lithium ion secondary battery, a compound containing lithium is used as a positive electrode material, and a carbon material such as graphite or coke is used as a negative electrode material. Further, between the positive electrode and the negative electrode, an electrolytic solution in which a lithium salt such as LiPF ₆ or LiBF ₄ is dissolved as an electrolyte in an aprotic solvent having a penetrating power such as propylene carbonate or ethylene carbonate, or an electrolytic solution thereof is used. An electrolyte layer of impregnated polymer gel is provided. These components are packaged and protected by the battery case packaging material.

An example of the structure of the packaging material for the battery case is a laminate material in which a heat-resistant resin stretched film layer as an outer layer, an aluminum foil layer, and a thermoplastic resin unstretched film layer as an inner layer are sequentially laminated. .. In the case of a battery case obtained using the battery case packaging material having such a structure, it is necessary to sufficiently seal the electrolytic solution. Therefore, between the aluminum foil layer and the inner layer, a resin containing a functional group having reactivity with isocyanate such as a carboxy group or an anhydride thereof, a hydroxyl group, and an adhesive layer containing a polyfunctional isocyanate compound are interposed. A battery case wrapping material that can be bonded together has been developed.

For example, in Patent Document 1, a modified polyolefin resin obtained by graft-polymerizing an ethylenically unsaturated carboxylic acid or an anhydride thereof to a propylene homopolymer or a copolymer of propylene and ethylene, and a polyfunctional isocyanate compound are organic. A method for forming an adhesive layer using a solvent-type adhesive dissolved or dispersed in a solvent is described.

Patent Document 2 describes an adhesive composition in which a polyolefin polyol and a polyfunctional isocyanate curing agent are essential components, and further a thermoplastic elastomer and/or a tackifier is added.

Patent Document 3 discloses a polyester polyol having a hydrophobic unit derived from a dimer fatty acid or a hydrogenated product thereof, and at least one main agent selected from the group consisting of isocyanate extended products of the polyester polyol, and crude tolylene diisocyanate, An adhesive composition containing a curing agent composed of one or more polyisocyanate compounds selected from the group consisting of crude diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate is described, respectively.

In Patent Document 4, a polyester polyol having a structural unit derived from a chain polyolefin polyol and/or a hydrogenated dimer acid and a structural unit derived from a hydrogenated dimer diol, a saturated or unsaturated cyclic hydrocarbon structure, and two or more A polyurethane polyol obtained by polyadding a hydroxyl group-containing hydrocarbon compound (b) having a hydroxyl group together and a component containing a polyisocyanate (c) is described. Further, as the hydroxyl group-containing hydrocarbon compound (b), a polyol containing a saturated alicyclic structure having a crosslinked structure is described.

JP, 2010-92703, A JP, 2005-63685, A JP, 2011-187385, A International Publication No. 2016/21279

However, the modified polyolefin resin of Patent Document 1 has a change over time during long-term storage and after dissolution in a solvent, and sometimes the operability during coating may become unstable, resulting in a decrease in yield and an increase in cost. ..

Further, in the cases of Patent Document 2 and Patent Document 3, it is necessary to provide a sealant layer capable of sufficiently suppressing contact between the adhesive layer and the electrolytic solution, which is a factor of cost increase for maintaining quality. ..

When the polyurethane polyol described in Patent Document 4 is used as an adhesive for an exterior material of a secondary battery such as a lithium ion secondary battery, there is room for further improvement in electrolytic solution resistance and heat resistance.

The present invention provides a polyurethane polyol and an adhesive composition having excellent adhesive strength between a metal foil and a resin film, and an adhesive having electrolytic solution resistance and heat resistance can be obtained. With the goal.

The configuration of the present invention for solving the above problems is as follows.
[1] A structural unit derived from a polyol containing at least one of a structural unit derived from a polyolefin polyol (a1) and a structural unit derived from a polyester polyol (a2), a structural unit derived from a polyisocyanate (b), and two or more units. It has a hydroxyl group, the polyolefin polyol (a1) does not contain an alicyclic structure, the polyester polyol (a2) has a structural unit derived from hydrogenated dimer acid and a structural unit derived from hydrogenated dimer diol, and polyisocyanate (B) is a polyurethane polyol having a saturated crosslinked alicyclic structure.
[2] The total content of the structural units derived from the polyolefin polyol (a1) and the structural units derived from the polyester polyol (a2) is 40% by mass or more and 95% by mass or less, and the content of the structural units derived from the polyisocyanate (b) is Is 5% by mass or more and 60% by mass or less, the polyurethane polyol according to [1].
[3] The polyurethane polyol according to [1] or [2], which contains a structural unit derived from the polyolefin polyol (a1), and the bonds between carbon atoms contained in the polyolefin polyol (a1) are all single bonds.
[4] The polyurethane polyol according to any one of [1] to [3], which contains a structural unit derived from the cyclic polyol (a3) having a cyclic hydrocarbon structure and two or more hydroxyl groups.
[5] The polyurethane polyol according to [4], which comprises at least one of the structural unit derived from the polyolefin polyol (a1) and the structural unit derived from the polyester polyol (a2), and the structural unit derived from the cyclic polyol (a3). ..
[6] The polyurethane polyol according to [4] or [5], wherein the cyclic polyol (a3) is a polyol containing a saturated crosslinked alicyclic structure.
[7] The polyurethane polyol according to [4] or [5], wherein the cyclic polyol (a3) is a bisphenol compound.
[8] The content of the cyclic polyol (a3) is 5 to 60 parts by mass with respect to 100 parts by mass of the total amount of the polyolefin polyol (a1) and the polyester polyol (a2), and Polyurethane polyol.
[9] Curing containing the polyurethane polyol (A) according to any one of [1] to [8] and at least one of saturated aliphatic polyisocyanate, saturated alicyclic polyisocyanate, and aromatic polyisocyanate An adhesive composition containing the agent (B).
[10] The adhesive composition according to [9], wherein the amount of the isocyanato group contained in the curing agent (B) is 1 to 20 molar equivalents per 1 molar equivalent of the hydroxyl group contained in the polyurethane polyol (A).
[11] The adhesive composition according to [9] or [10], which further contains a solvent (C).
[12] A first base material, a second base material, and an adhesive layer provided between the first base material and the second base material, wherein the adhesive layer is [9 ]-[11] Laminated material containing the hardened|cured material of the adhesive composition in any one.
[13] The laminate material according to [12], wherein the first base material is a metal foil and the second base material is a resin film.
[14] A lithium ion secondary battery including a packaging material for a battery exterior, which comprises the laminate material according to [13].

According to the present invention, there is provided a polyurethane polyol and an adhesive composition which have an excellent adhesive force between a metal foil and a resin film, and which can obtain an adhesive having electrolytic solution resistance and heat resistance. You can

Hereinafter, embodiments of the present invention will be described in detail. A preferred application of the polyurethane polyol and the adhesive composition described here is an adhesive for laminating a metal foil and a resin film, and a particularly preferred application is a metal foil and a resin film for a battery exterior packaging material. It is an adhesive for lamination, but is not limited to these.

Unless otherwise specified, "-" means not less than the value before the description "-" and not more than the value after the description "-". For example, "1-2" means 1 or more and 2 or less. Means that.

"Number average molecular weight" and "weight average molecular weight" are standard polystyrene conversion values measured by size exclusion chromatography (SEC), for example, gel permeation chromatography (GPC).

The bond derived from an isocyanato group and a hydroxyl group is referred to as an isocyanato-hydroxyl bond, and a polyol-derived structural unit is a structure derived from a polyol between adjacent isocyanato-hydroxyl bonds, or an isocyanato-hydroxyl bond, It has a structure derived from a polyol between the terminal hydroxyl group or a group to be a derivative thereof. The polyol is a compound having two or more hydroxyl groups, and examples thereof include a polyolefin polyol (a1), a polyester polyol (a2), and a cyclic polyol (a3) described later.

The structural unit derived from polyisocyanate is a structure derived from polyisocyanate between adjacent isocyanato-hydroxyl bonds, or isocyanato-hydroxyl bond, and polyisocyanate derived from the terminal isocyanato group or a group to be a derivative thereof. The structure of The polyisocyanate is a compound having two or more isocyanato groups including the polyisocyanate (b) described below.

The isocyanato-hydroxyl bond is preferably a urethane bond formed by the reaction of one isocyanato group and one hydroxyl group, but for example, a bond formed by two isocyanato groups and one hydroxyl group, etc. Good.

The “ethylenic double bond” means a double bond between carbon atoms excluding carbon atoms forming an aromatic ring.

The "crosslinked alicyclic structure" means a structure in which carbon atoms forming an alicycle are bridged between carbon atoms which are not adjacent to each other, and examples thereof include norbornene and adamantane. The “saturated crosslinked alicyclic structure” means a structure having no unsaturated bond in the crosslinked alicyclic structure. The "unsaturated crosslinked alicyclic structure" means a structure having an unsaturated bond in the crosslinked alicyclic structure.

"Hydrogenation" used as a prefix of an unsaturated compound name means a hydrogenated product of the unsaturated compound.

<1. Polyurethane polyol (A)>
The polyurethane polyol (A) according to the present embodiment comprises a polyol-derived structural unit containing at least one of a structural unit derived from a polyolefin polyol (a1) and a structural unit derived from a polyester polyol (a2), and a polyisocyanate (b)-derived structural unit. And a structural unit of 2 or more and two or more hydroxyl groups. Further, the polyurethane polyol (A) preferably contains a structural unit derived from the cyclic polyol (a3).

The polyurethane polyol (A) may include a structural unit derived from a polyol other than the polyolefin polyol (a1), the polyester polyol (a2), and the cyclic polyol (a3) (hereinafter sometimes referred to as “other polyol”). Good. However, in the polyurethane polyol (A), the structural unit derived from the polyol is at least one of the structural unit derived from the polyolefin polyol (a1) and the structural unit derived from the polyester polyol (a2), and the structural unit derived from the cyclic polyol (a3). It is preferably composed only of units. That is, it is preferable that the polyurethane polyol (A) does not contain structural units derived from other polyols.

As described below, the polyisocyanate (b) is a compound having two or more isocyanato groups and a saturated crosslinked alicyclic structure, but the polyurethane polyol (A) is a polyisocyanate other than the polyisocyanate (b) (hereinafter , Sometimes referred to as “other polyisocyanate”), that is, the polyurethane polyol (A) has a structural unit derived from a compound having two or more isocyanato groups but not a saturated cross-linked alicyclic structure. May be included. However, in the polyurethane polyol (A), the structural unit derived from polyisocyanate is preferably a structural unit derived from polyisocyanate (b). That is, it is preferable that the polyurethane polyol (A) does not contain a structural unit derived from other polyisocyanate.

Hereinafter, each structural unit contained in the polyurethane polyol (A) will be described in detail, and then the content of each structural unit will be described.

[1-1. Polyolefin polyol (a1)]
The polyolefin polyol (a1) is a compound containing a polyolefin skeleton, which is a polymer or copolymer of one or more olefins, and two or more hydroxyl groups, and having no alicyclic structure. Specific examples thereof include polydiene polyols such as polybutadiene polyol and polyisoprene polyol, and graft copolymers of polydiene polyol and polyolefin. These polymers may contain only 1 type, and may contain 2 or more types. From the viewpoint of the electrolytic solution resistance of the adhesive layer obtained from the polyurethane polyol (A), it is preferable that the polyolefin polyol (a1) does not contain an unsaturated hydrocarbon structure in the structure. That is, in the polyolefin polyol (a1), it is preferable that all carbon atoms have single bonds. Examples of the polyolefin polyol (a1) containing no unsaturated hydrocarbon structure include the above-mentioned hydrogenated polydiene polyols and hydrogenated graft copolymers of polydiene polyols and polyolefins. Examples of these commercially available products include GI-1000, GI-2000, GI-3000 (all manufactured by Nippon Soda Co., Ltd.), and Epol (registered trademark, manufactured by Idemitsu Kosan Co., Ltd.).

The number average molecular weight of the polyolefin polyol (a1) is preferably 500 or more. This is because when the polyurethane polyol (A) is used as an adhesive for laminating a metal foil and a resin film, the electrolytic solution resistance of the adhesive layer is improved. From this point of view, the number average molecular weight of the polyolefin polyol (a1) is more preferably 1,000 or more, further preferably 1200 or more.

The number average molecular weight of the polyolefin polyol (a1) is preferably 10,000 or less. Further, in order to improve the solubility of the polyurethane polyol (A) in a solvent, and when the polyurethane polyol (A) is used as an adhesive for laminating a metal foil and a resin film, when the adhesive is applied to a substrate. This is because the operability of is improved. From this viewpoint, the number average molecular weight of the polyolefin polyol (a1) is more preferably 5,000 or less, further preferably 3,000 or less.

[1-2. Polyester polyol (a2)]
The polyester polyol (a2) has a structural unit derived from hydrogenated dimer acid and a structural unit derived from hydrogenated dimer diol. This is because when the polyurethane polyol (A) is used as an adhesive for laminating a metal foil and a resin film, the electrolytic solution resistance of the bonded portion is improved.

Hydrogenated dimer acid is a saturated dicarboxylic acid obtained by hydrogenating the ethylenic double bond of dimer acid. Examples of commercially available hydrogenated dimer acid include EMPOL1008 and EMPOL1062 (both manufactured by BASF), PRIPOL1009 (registered trademark, manufactured by Croda), and the like.

Dimer acid is a dimer acid obtained by reacting fatty acids having an ethylenic double bond and having 14 to 22 carbon atoms (hereinafter, sometimes referred to as “unsaturated fatty acid”) with an ethylenic double bond. Is. The dimer acid is preferably one obtained by reacting an unsaturated fatty acid having 2 to 4 ethylenic double bonds with an unsaturated fatty acid having 1 to 4 ethylenic double bonds, and an ethylenic double bond. More preferred is one obtained by reacting an unsaturated fatty acid having two of the above with an unsaturated fatty acid having one or two ethylenic double bonds.

Examples of unsaturated fatty acids include tetradecenoic acid (tuduic acid, mackouic acid, myristooleic acid), hexadecenoic acid (palmitoleic acid, etc.), octadecenoic acid (oleic acid, elaidic acid, vaccenic acid, etc.), eicosenoic acid (gadrain). Acid, etc.), docosenoic acid (erucic acid, cetrainic acid, brassic acid, etc.), tetradecadienoic acid, hexadecadienoic acid, octadecadienoic acid (linoleic acid, etc.), eicosadienoic acid, docosadienoic acid, octadecatrienoic acid (linolene) Acid etc.), and eicosatetraenoic acid (arachidonic acid etc.). As the unsaturated fatty acid used as a raw material of dimer acid, oleic acid, linoleic acid or a mixture thereof is particularly preferable.

The dimer acid may produce a mixture of dimer acids having different structures due to different double bond sites or isomerization. As the dimer acid, only the necessary one may be separated from these mixtures and used, but it may be used as a mixture containing two or more kinds. Further, as an unreacted raw material or by-product, a monomer acid may be contained, or a polymer acid of trimer acid or more may be contained. However, the content of the monomer acid with respect to the total amount of the dimer acid, the monomer acid, and the polymer acid is preferably 6% by mass or less, and more preferably 4% by mass or less. Further, the content of the polymer acid is preferably 6% by mass or less, and more preferably 4% by mass or less, based on the total amount of the dimer acid, the monomer acid and the polymer acid.

The hydrogenated dimer diol is a compound in which the carboxy group of hydrogenated dimer acid is replaced with a hydroxyl group. The hydrogenated dimer diol can be obtained, for example, by reducing hydrogenated dimer acid or a lower alcohol ester thereof in the presence of a catalyst, but is not limited thereto. Also, for example, the raw material may be dimer acid, and hydrogenated after reduction. Examples of commercially available hydrogenated dimer diols include Sovermol 908 (manufactured by BASF) and PRIPOL 2033 (registered trademark, manufactured by Croda).

The polyester polyol (a2) can be produced by subjecting hydrogenated dimer acid and hydrogenated dimer diol to a condensation reaction in the presence of an esterification catalyst. Alternatively, the polyester polyol (a2) can also be produced by subjecting a lower alkyl ester of hydrogenated dimer acid and a hydrogenated dimer diol to a transesterification reaction in the presence of a transesterification catalyst.

[1-3. Cyclic polyol (a3)]
The cyclic polyol (a3) is a compound having a cyclic hydrocarbon structure and two or more hydroxyl groups. The cyclic polyol (a3) may be composed of a single compound or may be composed of two or more compounds. The cyclic hydrocarbon structure may be either an alicyclic structure or an aromatic ring structure, but is preferably an alicyclic structure, and more preferably a saturated alicyclic structure. When the polyurethane polyol (A) is used as an adhesive for laminating a metal foil and a resin film, the cyclic polyol (a3) is unsaturated or saturated alicyclic carbonized in order to enhance the electrolytic solution resistance of the bonded portion. It is preferable that the compound has a hydrogen structure and two or more hydroxyl groups, and the structure of the other part is a hydrocarbon.

Examples of the saturated cyclic structure include a cycloalkane skeleton such as a cyclopentane skeleton, a cyclohexane skeleton, and a cycloheptane skeleton. Examples of the cyclic polyol (a3) having such a structure include cyclopentanediol, cyclohexanediol, cyclohexanedimethanol and the like. Examples of the saturated cyclic structure include crosslinked alicyclic structures such as a norbornane skeleton, an adamantane skeleton, and a tricyclodecane skeleton. Examples of the cyclic polyol (a3) having such a structure include norbornane diol, adamantane diol, tricyclodecane dimethanol and the like.

As the cyclic polyol (a3), those having a saturated crosslinked alicyclic structure are preferable. Preferred examples of the compound having a saturated crosslinked alicyclic structure include norbornanediol, adamantanediol, tricyclodecanedimethanol and the like. Examples of commercially available products thereof include adamantane triol (manufactured by Idemitsu Kosan Co., Ltd., Mitsubishi Gas Chemical Co., Inc.) and TCD alcohol DM (manufactured by Oxea Co.).

Further, the cyclic polyol (a3) may have an unsaturated cyclic structure. Examples of the unsaturated cyclic structure include cyclopentene skeleton, cyclohexene skeleton, cycloheptene skeleton, cycloalkene skeleton such as [4n]annulene skeleton, benzene skeleton, naphthalene skeleton, anthracene skeleton, azulene skeleton, and conjugated ring structure such as [4n+2]annulene skeleton. And an unsaturated alicyclic structure having a crosslinked structure such as dicyclopentadiene skeleton. Examples of the cyclic polyol (a3) having such a structure include cyclohexene diol, biphenol, bisphenol, naphthalene diol, dicyclopentadienyl dimethanol and the like. These may be used alone or in combination of two or more.

Among these compounds having an unsaturated cyclic structure, bisphenol is preferable as the cyclic polyol (a3), and bisphenols such as bisphenol A, bisphenol B, bisphenol C, bisphenol E, bisphenol F, bisphenol G, and bisphenol Z. And preferably contains bisphenol A.

[1-4. Polyisocyanate (b)]
Polyisocyanate (b) is a compound having two or more isocyanato groups and a saturated crosslinked alicyclic structure. Examples of the polyisocyanate (b) include 1,3-diisocyanatoadamantane, 3(4),8(9)-bis(isocyanatomethyl)tricyclo[5.2.1.0(2,6)]decane. , Norbornane diisocyanate, allophanated multimers, isocyanurates, and biuret modified products thereof.

The polyisocyanate (b) is preferably one in which the portion other than the isocyanato group is composed of hydrocarbon. Examples of such compounds include 1,3-diisocyanatoadamantane, 3(4),8(9)-bis(isocyanatomethyl)tricyclo[5.2.1.0(2,6)]decane and norbornane. Examples thereof include diisocyanate, and examples of commercially available products include Cosmonate NBDI (manufactured by Mitsui Chemicals, Inc.). It also includes a saturated cross-linked alicyclic structure such as 1,3-diaminoadamantane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0(2,6)]decane. It can also be synthesized from polyamine by the phosgenation method. Examples of the phosgenation method include an amine hydrochloride phosgenation method and a cold two-stage phosgenation method.

[1-5. Content of Each Structural Unit of Polyurethane Polyol (A)]
The total content of the structural units derived from the polyolefin polyol (a1) and the structural units derived from the polyester polyol (a2) in the polyurethane polyol (A) is preferably 40% by mass or more, and more preferably 50% by mass or more. It is more preferably 60% by mass or more. The total content of the structural units derived from the polyolefin polyol (a1) and the polyester polyol (a2) in the polyurethane polyol (A) is preferably 95% by mass or less, and 90% by mass or less. More preferably, it is even more preferably 80% by mass or less.

When the polyurethane polyol (A) contains a structural unit derived from the cyclic polyol (a3), the cyclic unit based on 100 parts by mass of the total amount of the structural unit derived from the polyolefin polyol (a1) and the structural unit derived from the polyester polyol (a2). The content of the structural unit derived from the polyol (a3) is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and further preferably 10 parts by mass or more. This is because when the polyurethane polyol (A) is used as an adhesive for laminating a metal foil and a resin film, the electrolytic solution resistance of the bonded portion is improved.

When the polyurethane polyol (A) contains a structural unit derived from the cyclic polyol (a3), the cyclic unit based on 100 parts by mass of the total amount of the structural unit derived from the polyolefin polyol (a1) and the structural unit derived from the polyester polyol (a2). The content of the structural unit derived from the polyol (a3) is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and further preferably 45 parts by mass or less. This is because the solubility of the polyurethane polyol (A) in the solvent and the operability at the time of applying the adhesive composition described later are improved.

The content of the structural unit derived from the polyisocyanate (b) in the polyurethane polyol (A) is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 12% by mass or more. preferable. The content of the structural unit derived from the polyisocyanate (b) in the polyurethane polyol (A) is preferably 60% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. preferable.

<2. Method for producing polyurethane polyol (A)>
The method for producing the polyurethane polyol (A) is not particularly limited, but is, for example, in the presence or absence of a urethane-forming catalyst such as dibutyltin dilaurate, dioctyltin dilaurate, bismuth tris 2-ethylhexanoate, zirconium tetraacetylacetonate. In the following, it is possible to carry out a polyaddition reaction between at least one of the polyolefin polyol (a1) and the polyester polyol (a2) and the polyisocyanate (b). Further, as the component to be polymerized, the cyclic polyol (a3) and other copolymerizable compounds can be contained. Here, the “component to be polymerized” refers to a component which can be a structural unit of the polyurethane polyol (A) by polyaddition reaction, that is, urethanization.

The urethanization catalyst is preferably used because it can shorten the polymerization time. Further, the urethanization catalyst can also act as a curing accelerator when the polyurethane polyol (A) and the curing agent (B) described later react and cure. However, the amount of the urethanization catalyst used is preferably 0.001 to 1 part by mass, more preferably 0.005 to 0.5 part by mass, and 0.1. 01 to 0.3 parts by mass is more preferable. In the polyaddition reaction, the order of adding the components to be polymerized is not particularly limited, but the components to be polymerized may be reacted all at once, and after reacting each polyol with the polyisocyanate (b), All components may be mixed and further reacted. Further, for example, after the cyclic polyol (a3) is reacted with the polyisocyanate (b) to obtain a prepolymer, at least one of the polyolefin polyol (a1) and the polyester polyol (a2) is reacted to produce a polyurethane polyol ( The method of obtaining A) is mentioned.

In addition, this polyaddition reaction may be carried out in a solvent. The solvent to be used is not particularly limited, but if the solvent (C) described later is used, steps such as solvent distillation can be omitted, and the production can be performed at a lower cost.

The ratio NCO/OH [mol/mol] of the number of isocyanato groups to the number of hydroxyl groups contained in the polyol in the component to be polymerized during the production of the polyurethane polyol (A) is preferably 0.5 or more. This is because when the polyurethane polyol (A) is used as an adhesive for laminating a metal foil and a resin film, an excellent adhesive force can be obtained even when it comes into contact with an electrolytic solution. From this viewpoint, the NCO/OH in the component to be polymerized is more preferably 0.7 or more, further preferably 0.8 or more.

The NCO/OH in the component to be polymerized is preferably 1.3 or less, more preferably 1.2 or less, and further preferably 1.1 or less. This is because gelling during the production of the polyurethane polyol (A) is suppressed and the operability during application of the adhesive composition is improved.

The NCO/OH in the component to be polymerized is particularly preferably 0.95 or less. This is because the amount of hydroxyl groups at the molecular ends of the product is increased, that is, the polyurethane polyol (A) is efficiently produced.

The amount of hydroxyl groups contained in each polyol is the amount determined by the titration method of JIS K 1557-1. The amount of isocyanato group contained in each isocyanate component is the amount determined by the titration method of JIS K 6806.

<3. Adhesive composition>
The adhesive composition according to this embodiment contains a polyurethane polyol (A) and a curing agent (B). The adhesive composition may contain the solvent (C) and other components. The details of the polyurethane polyol (A) are as described above.

[3-1. Curing agent (B)]
The curing agent (B) contains at least one of saturated aliphatic polyisocyanate, saturated alicyclic polyisocyanate, and aromatic polyisocyanate. The curing agent (B) is a component other than the polyisocyanate (b) used when producing the polyurethane polyol (A).

Examples of the curing agent (B) include aliphatic diisocyanates such as hexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexane methylene diisocyanate, 1,4-cyclohexane diisocyanate, and isophorone diisocyanate. A saturated alicyclic diisocyanate such as methylene bis(4-cyclohexyl isocyanate), 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, norbornane diisocyanate, 2,4-tolylene diisocyanate Aromatic diisocyanates such as 2,6-tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate (monomeric MDI), 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, polymethylene polyphenyl polyisocyanate (Polymeric MDI), and allophanated polymers, isocyanurates, and biuret modified products thereof. These may be used alone or in combination of two or more. A combination of a saturated aliphatic diisocyanate and a saturated alicyclic diisocyanate from the viewpoint of the electrolytic solution resistance of an adhesive layer obtained from an adhesive for laminating a metal foil using a polyurethane polyol (A) and a resin film, and, A combination of a saturated aliphatic diisocyanate and a polymeric MDI and a combination of a saturated aliphatic diisocyanate, a saturated alicyclic diisocyanate and a polymeric MDI are more preferable.

The amount of the isocyanato group contained in the curing agent (B) is preferably 1 molar equivalent or more based on 1 molar equivalent of the hydroxyl group contained in the polyurethane polyol (A). This is because the adhesive strength of the adhesive layer obtained from the adhesive composition using the polyurethane polyol (A), particularly to the resin film, becomes good. The content of the isocyanato group contained in the curing agent (B) is preferably 20 molar equivalents or less, more preferably 15 molar equivalents or less, and even more preferably 13 molar equivalents or less based on 1 molar equivalent of the hydroxyl group contained in the polyurethane polyol (A). preferable. This is because the adhesive force of the adhesive layer obtained from the adhesive composition using the polyurethane polyol (A) is less likely to decrease even when contacted with the electrolytic solution.

[3-2. Solvent (C)]
The solvent (C) is not particularly limited as long as it can dissolve or disperse the polyurethane polyol (A) and the curing agent (B). Examples of the solvent (C) include aromatic organic solvents such as toluene and xylene, alicyclic organic solvents such as cyclohexane, methylcyclohexane and ethylcyclohexane, and aliphatic organic solvents such as n-hexane and n-heptane. Examples thereof include ester-based organic solvents such as ethyl acetate, propyl acetate and butyl acetate, and ketone-based organic solvents such as acetone, methyl ethyl ketone and methyl butyl ketone. These may be used alone or in combination of two or more.

From the viewpoint of the solubility of the polyurethane polyol (A), the solvent (C) is preferably used alone or in combination of two or more of ethyl acetate, propyl acetate, butyl acetate, toluene, methylcyclohexane, and methyl ethyl ketone. It is more preferable to use one of the above, toluene, and methyl ethyl ketone, or a mixture of two of them.

The content of the solvent (C) is 40 parts by mass with respect to 100 parts by mass of the total amount ((A)+(B)+(C)) of the polyurethane polyol (A), the curing agent (B) and the solvent (C). It is preferably at least 50 parts by mass, more preferably at least 50 parts by mass, still more preferably at least 80 parts by mass. This is because operability at the time of applying the adhesive composition is improved.

The content of the solvent (C) is 95 parts by mass or less based on 100 parts by mass of the total amount ((A)+(B)+(C)) of the polyurethane polyol (A), the curing agent (B) and the solvent (C). The amount is preferably 90 parts by mass or less, and more preferably 90 parts by mass or less. This is because the thickness controllability of the adhesive layer obtained by curing the adhesive composition is improved.

[3-3. Other ingredients]
The adhesive composition may contain a reaction accelerator, a tackifier, a plasticizer, a thermoplastic resin, a thermoplastic elastomer, etc., if necessary and within the range in which the effects of the present invention can be obtained.

The reaction accelerator is for accelerating the reaction between the polyurethane polyol (A) and the curing agent (B), and includes, for example, dioctyltin dilaurate, dioctyltin diacetate, and tertiary amine which are organic tin compounds. 2,4,6-tris(dimethylaminomethyl)phenol, dimethylaniline, dimethylparatoluidine, N,N-di(β-hydroxyethyl)-p-toluidine and the like can be mentioned. These reaction accelerators can be used alone or in combination of two or more kinds.

The tackifier is not particularly limited, but examples of the natural resin include polyterpene resin and rosin resin. The tackifier may be a petroleum-based resin, for example, an aliphatic (C5)-based resin obtained from a cracked oil fraction of naphtha, an aromatic (C9)-based resin, a copolymer (C5/C9)-based resin, a fat. Examples thereof include cyclic resins. Further, the tackifier may be a hydrogenated resin obtained by hydrogenating the double bond portion of the resin mentioned above. The tackifier may consist of only one kind of compound or may contain two or more kinds of compounds.

The plasticizer is not particularly limited, but examples thereof include liquid rubber such as polyisoprene and polybutene, process oil, and the like. The plasticizer may consist of only one type of compound or may contain two or more types of compounds.

Examples of the thermoplastic resin and the thermoplastic elastomer include acid-modified polyolefin resin. Examples of the thermoplastic resin and the thermoplastic elastomer include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, SEBS (styrene-ethylene-butylene-styrene copolymer), SEPS (styrene-ethylene). -Propylene-styrene copolymer) and the like.

<4. Laminate material>
The laminating material according to the present embodiment includes a first base material, a second base material, and an adhesive layer provided between the first base material and the second base material. The layer comprises a cured product of the above adhesive composition. Here, the cured product of the adhesive composition is not limited to the cured product of the resin component, and includes an initiator used in the synthesis of the resin contained, various additives, or components derived from these components. Good.

The first base material and the second base material may be made of the same material or different materials. The material of the first base material and the second base material is preferably a metal foil or a resin film. As a preferable constitution of the laminate material, for example, the first base material is a metal foil and the second base material is a resin film, and the first base material and the second base material are both resin films. , And the first base material and the second base material are both metal foils. Among these configurations, the adhesive composition of the present embodiment has a configuration in which the first base material is a metal foil and the second base material is a resin film, that is, for bonding between the metal foil and the resin film. It is very effective against it.

Examples of the method for joining the metal foil and the resin film using the adhesive composition according to this embodiment include a heat laminating method, an extrusion laminating method, and a dry laminating method. Examples of the heat laminating method include a method of heating and melting the adhesive composition on the coated surface thereof. Examples of the extrusion laminating method include a method in which a molten adhesive composition is poured between a metal foil and a resin film and then extruded. As the dry laminating method, a method of applying an adhesive composition containing a solvent (C) to at least one of a metal foil and a resin film, drying the same, and then laminating the metal foil and the resin film and press-bonding the same. ..

The use of the laminate material according to this embodiment is not particularly limited, but is preferably used for packaging. The contents packaged in this laminate material include liquid substances containing acids, alkalis, organic solvents, etc., such as putty (thick putty, thin putty, etc.), paint (oil-based paint, etc.), lacquer ( Clear lacquer, etc.) and solvent-based compounds such as automobile compounds. This laminate material has a particularly preferable application as an outer packaging material for a lithium ion secondary battery.

<5. Battery packaging material>
The above-mentioned laminate material is used for the battery exterior packaging material of the present embodiment. A preferred configuration of the laminate material used for the battery exterior packaging material of the present embodiment is a resin film layer, an adhesive layer, and a metal foil layer provided to face the resin film with the adhesive layer sandwiched therebetween, An outer layer is provided facing the surface of the metal foil layer opposite to the adhesive layer.

As another configuration, for example, a first intermediate resin layer may be included between the metal foil layer and the outer layer in order to improve properties such as mechanical strength and resistance to electrolytic solution, and the metal foil layer and the adhesive layer may be included. A second intermediate resin layer may be included between and. Further, for example, a coat layer may be provided on the surface of the outer layer opposite to the metal foil layer. The following configurations (1) to (8) are specifically considered as preferable forms of the battery outer packaging material. Although not shown below, the layers other than the metal foil layer and the resin film layer may be bonded with an adhesive.

(1) Outer layer/metal foil layer/adhesive layer/resin film layer (2) Outer layer/first intermediate resin layer/metal foil layer/adhesive layer/resin film layer (3) Outer layer/metal foil layer/second intermediate Resin layer/adhesive layer/resin film layer (4) outer layer/first intermediate resin layer/metal foil layer/second intermediate resin layer/adhesive layer/resin film layer (5) coat layer/outer layer/metal foil layer/ Adhesive layer/resin film layer (6) coat layer/outer layer/first intermediate resin layer/metal foil layer/adhesive layer/resin film layer (7) coat layer/outer layer/metal foil layer/second intermediate resin layer/ Adhesive layer/resin film layer (8) coat layer/outer layer/first intermediate resin layer/metal foil layer/second intermediate resin layer/adhesive layer/resin film layer

[5-1. Resin film layer)
The resin film layer has a heat-sealing property and improves the chemical resistance of the battery exterior packaging material against the electrolytic solution of the lithium-ion secondary battery. The film constituting the resin film layer is preferably a heat-fusible resin film such as polypropylene, polyethylene, maleic acid-modified polypropylene, ethylene-acrylate copolymer or ionomer resin.

The thickness of the resin film layer is preferably 9 μm or more. This is because the packaging material for battery exterior has sufficient heat sealing strength and good corrosion resistance to the electrolytic solution and the like. From this viewpoint, the thickness of the resin film layer is more preferably 20 μm or more, further preferably 40 μm or more. The thickness of the resin film layer is preferably 100 μm or less. This is because the strength of the battery outer packaging material is improved and the moldability is improved. From this viewpoint, the thickness of the resin film layer is more preferably 80 μm or less.

[5-2. Adhesive layer]
The adhesive layer is a layer containing a cured product of the adhesive composition according to the present embodiment, and the detailed configuration of the adhesive composition is as described above.

[5-3. Metal foil layer)
The metal foil layer serves as a barrier layer that prevents the ingress of oxygen and moisture into the package. The material of the metal foil layer is preferably pure aluminum (1000 series) or O material (soft material) of aluminum-iron alloy. The thickness of the metal foil layer is preferably 10 μm or more. This is for suppressing the breakage of the metal foil layer and the generation of pinholes when the laminate material is formed. From this viewpoint, the thickness of the metal foil layer is preferably 30 μm or more, and more preferably 40 μm or more.

The thickness of the metal foil layer is preferably 100 μm or less. This is to reduce the size and weight of the battery, improve the volume and mass energy density, and suppress an increase in the manufacturing cost of the battery. From this viewpoint, the thickness of the metal foil layer is preferably 50 μm or less. The metal foil layer is subjected to a chemical conversion treatment such as an undercoat treatment with a silane coupling agent or a titanium coupling agent or a chromate treatment in order to improve the adhesiveness with the resin film and the corrosion resistance of the metal foil. Preferably.

[5-4. Outer layer)
A resin film is preferably used for the outer layer. The resin film used as the outer layer preferably has excellent heat resistance, moldability, insulation properties, and the like, and it is preferable to use a stretched film of polyamide (nylon) resin or polyester resin. The thickness of this outer layer is preferably 9 μm or more. This is to prevent necking of the outer layer and molding failure of the laminate material when the laminate material is molded. From this viewpoint, the thickness of the outer layer is more preferably 10 μm or more, further preferably 20 μm or more.

The thickness of the outer layer is preferably 50 μm or less. This is to reduce the size and weight of the battery, improve the volume and mass energy density, and suppress an increase in the manufacturing cost of the battery. From this viewpoint, the thickness of the outer layer is more preferably 40 μm or less, further preferably 30 μm or less.

When a stretched film is used as the outer layer, the tensile strength in each of the three directions of 0°, 45°, and 90° is preferably 150 N/mm ² or more when the stretching direction is 0°, and 200 N/mm ² or more. mm ² or more is more preferable, and 250 N/mm ² or more is still more preferable. Further, the elongation due to the above-mentioned three-direction tension is preferably 80% or more, more preferably 100% or more, and further preferably 120% or more. This is because it is possible to obtain a molded product having a portion with a high curvature. The values of the tensile strength and the elongation due to the tensile are values up to breakage in the tensile test of the film (length of test piece 150 mm×width 15 mm×thickness 30 μm, pulling speed 100 mm/min). The test piece is cut out in each of the above three directions, and the test is performed.

[5-6. Coat layer)
Examples of the coating layer include those coated with a polymer having a gas barrier property, those deposited with an inorganic oxide such as aluminum metal and silicon oxide/aluminum oxide, and the coating of a thin film of a metal and an inorganic material thereon. By providing the coat layer, it is possible to obtain a laminate material having more excellent water vapor and other gas barrier properties.

<6. Battery case>
The battery case according to the present embodiment is obtained by molding the above-mentioned laminate material (battery exterior packaging material). Examples of the molding method include drawing and blow molding. The laminate material according to the present embodiment has excellent electrolytic solution resistance, heat resistance, and further excellent gas barrier properties against water vapor, oxygen, etc., and is suitable as a battery case for a non-aqueous secondary battery, particularly a lithium ion secondary battery. Used. Moreover, since the laminate material according to the present embodiment has very good moldability, it is possible to obtain battery cases of various shapes having deep irregularities, high curvature, or the like. The forming method is not particularly limited, but when formed by deep drawing or stretch forming, a battery case having a complicated shape and high dimensional accuracy can be manufactured.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

In addition, unless otherwise specified, the number average molecular weights in the following examples use gel permeation chromatography (Showa Denko Co., Ltd., Shodex GPC System-11, "Shodex" (registered trademark)), and the following conditions. It is a value obtained by measuring at room temperature at, and using a standard polystyrene calibration curve.
Column: Showa Denko KK, KF-806L
Column temperature: 40°C
Sample: 0.2 mass% tetrahydrofuran solution of sample polymer Flow rate: 2 ml/min Eluent: Tetrahydrofuran Detector: Differential refractometer (RI)

<1. Synthesis of polyisocyanate (b)>
[1-1. Polyisocyanate (b-1)]
Polyisocyanate (b-1) containing a saturated alicyclic structure having a crosslinked structure was obtained by a cold two-stage phosgenation method using 1,3-diaminoadamantane as a raw material. The specific synthesis method is as follows.

After dissolving 33.2 g of 1,3-diaminoadamantane (manufactured by Tokyo Chemical Industry Co., Ltd.) in 200 ml of o-dichlorobenzene, a four-necked flask equipped with a stirrer, a cooler, a thermometer and a hydrogen chloride gas introduction tube While stirring, dry hydrogen chloride gas was introduced. Then, the temperature was raised to 130° C., phosgene was introduced at a rate of 40 g per hour for 5 hours, then the reaction temperature was set to 180° C., and phosgene was introduced at a rate of 20 g per hour for 5 hours, and further at the same temperature for 1 hour. Hold for time to complete reaction. After distilling off o-dichlorobenzene from the obtained mixture under reduced pressure, 21.0 g of polyisocyanate (b-1) (NCO content of 38.50) was obtained as a transparent liquid fraction having a boiling point of 169 to 173° C./0.4 mmHg. 4% by mass) was obtained.

[1-2. Polyisocyanate (b-2)]
Saturated alicyclic structure having a crosslinked structure by a cold two-stage phosgenation method using 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0(2,6)]decane as a raw material A polyisocyanate containing was obtained. In a four-necked flask equipped with a stirrer, a cooler, a thermometer and a hydrogen chloride gas introduction tube, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0(2. 6)] Decane (manufactured by Xuzhou Dewei Chemical Technology Co., Ltd.) (38.8 g) was dissolved in 200 ml of o-dichlorobenzene, and then dry hydrogen chloride gas was introduced while stirring. After that, the temperature was raised to 130° C., phosgene was introduced at a rate of 40 g per hour for 5 hours, then the reaction temperature was set to 180° C., and phosgene was introduced at a rate of 20 g per hour for 5 hours, and at the same temperature for 1 hour. Hold for time to complete reaction. After distilling off o-dichlorobenzene from the obtained mixture under reduced pressure, 26.2 g of polyisocyanate (b-2) (NCO content of 34.30) was obtained as a transparent liquid fraction having a boiling point of 169 to 173° C./0.4 mmHg. 1% by mass) was obtained.

<2. Synthesis of polyester polyol (a2)>
In a reaction vessel equipped with a stirrer and a water separator, 220 g of "Sovermol 908" (manufactured by BASF) as hydrogenated dimer diol, 230 g of "EMPOL1008" (manufactured by BASF) as hydrogenated dimer acid, and "KS" as butyltin dilaurate as a catalyst. -1260" (manufactured by Sakai Chemical Industry Co., Ltd.) was charged in an amount of 0.10 g, and the pressure was reduced to 150 mmHg in 60 minutes while allowing the condensed water to flow out at 240° C. under atmospheric pressure. , Polyester polyol (a2-1) was obtained.

<3. Synthesis of Polyurethane Polyisocyanate>
[3-1. Polyurethane polyisocyanate (1)]
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 23.29 g of bisphenol A (produced by Nippon Steel Chemical Co., Ltd., compound name 2,2-bis(4-hydroxyphenyl)propane), "KS-1260" ( 0.01 g of dibutyltin dilaurate manufactured by Sakai Chemical Industry, 31.50 g of “Cosmonate NBDI” (norbornane diisocyanate isocyanate manufactured by Mitsui Chemicals) and 113 g of methyl ethyl ketone were charged, and the mixture was stirred at 85-90 using an oil bath. The temperature was raised to. Then, the reaction was continued while stirring for 2.5 hours to obtain a methyl ethyl ketone solution of polyurethane polyisocyanate (1).

[3-2. Polyurethane polyisocyanate (2)]
A methyl ethyl ketone solution of polyurethane polyisocyanate (2) was obtained in the same manner as in the synthesis method of polyurethane polyisocyanate (1) except that 20 g of bisphenol F (manufactured by Honshu Chemical Industry Co., Ltd.) was used instead of bisphenol A.

<4. Synthesis of Polyurethane Polyol (A)>
Into a reaction vessel equipped with a stirrer, a thermometer, and a condenser, the components to be polymerized, the catalyst, and the amount of the antioxidant shown in Table 1 and 70 g of the solvent shown in Table 1 were charged and stirred. The temperature was raised to 85 to 90° C. using an oil bath. The solvent used in the polyurethane polyols (A-5) and (CA-2) was a mixed solvent of toluene and methyl ethyl ketone in a mass ratio of 1:1. Other than that, toluene was used. Then, the reaction was continued while stirring for 2.5 hours. The infrared absorption spectrum was measured, the absorption of the isocyanato group was confirmed to have disappeared, the reaction was terminated, and the amount of the solvent shown in Table 1 was added together with 70 g of the solvent previously charged to give the amount shown in Table 1. Thus, the mixture was stirred and dissolved to obtain a solution (solid content concentration 18% by mass) of polyurethane polyols (A-1) to (A-10) and polyurethane polyols (CA-1) to (CA-3).

<4. Preparation of adhesive composition>
The composition of each example and comparative example is shown in Table 2.

33.33 g of a solution of polyurethane polyols (A-1) to (A-10) and (CA-1) to (CA-2) (polyurethane polyol (A): 6.00 g, solvent (C): 27.33 g) Then, the amounts of the curing agent (B) and the solvent (C) shown in Table 2 were added together with the amount contained in the above solution so as to obtain the amounts shown in Table 2 to prepare an adhesive composition. In Examples 3 and 6 and Comparative Examples 1 and 2, the solvent used was a mixed solvent of toluene and methyl ethyl ketone in a mass ratio of 1:1.

<5. Evaluation method>
[5-1. Preparation of laminate material]
Using the respective adhesive compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 3, the structure of outer layer/adhesive layer for outer layer/metal foil layer/adhesive layer/resin film was formed as follows. The laminated material was prepared by a dry lamination method.

On one side of a stretched polyamide film (thickness: 25 μm) as an outer layer, a urethane-based dry laminating adhesive (AD502/CAT10L manufactured by Toyo Morton Co., Ltd.) as an outer layer adhesive was applied at a coating amount of 3 g/m ² (when applied). Applied. An aluminum-iron alloy aluminum foil (AA standard 8079-O material, thickness 40 μm) was laminated as a metal foil layer on the surface of the outer layer on which the adhesive was applied. The surface of the laminated aluminum foil (the surface opposite to the outer layer) was coated with one of the adhesive compositions prepared in Examples and Comparative Examples so that the thickness after drying was 2 μm. An unstretched polypropylene film (thickness 30 μm) as a resin film was laminated on the surface of the aluminum foil coated with the adhesive composition.

The laminate material obtained through the above steps was cured at a temperature of 40° C. and a humidity of 5% RH for 5 days.

[5-2. Evaluation methods for various peel strengths)
With respect to the obtained packaging material for a battery case, the normal T-shaped peel strength, the T-shaped peel strength after immersion in an electrolytic solution and the T-shaped peel strength in an atmosphere of 85° C. were measured. The measurement conditions and method are as follows (1) to (3). Each test was performed with n=2, and the average value was taken. The results are shown in Table 2.

(1) Normal T-shaped peel strength Measured based on JIS K 6854-2 (1999). The produced laminate material was cut out into a test piece having a length of 150 mm and a width of 15 mm. At the end of the test piece, the aluminum foil layer and the resin film are partially peeled, and the peeled portion is grasped by an apparatus and an Autograph AG-X (manufactured by Shimadzu Corporation) is used to obtain an atmosphere of 23° C. and 50% RH. It was peeled underneath at a peeling speed of 100 mm/min, and the 180° peel strength between the metal foil layer and the resin film layer was measured.

(2) T-shaped peel strength after immersion in electrolytic solution solvent A test piece having a length of 150 mm and a width of 15 mm was immersed in an electrolytic solution solvent (ethylene carbonate/diethyl carbonate, mass ratio 50/50), and kept in an atmosphere of 85° C. for 1 day. After leaving it for a while, it was taken out and the 180° peel strength between the aluminum foil layer and the unstretched polypropylene film layer was measured using the test piece in the same manner as in (1) above. The measuring method is based on JIS K 6854-2 (1999) as above.

(3) T-shaped peeling strength in an atmosphere of 85° C. A test piece having a length of 150 mm and a width of 15 mm was left in an atmosphere of 85° C., and after the temperature of the test piece reached 85° C., peeling was performed at a peeling speed of 100 mm/min. The 180° peel strength between the aluminum foil layer and the unstretched polypropylene film layer was measured. Based on JIS K 6854-2 (1999).

<6. Evaluation results>
From the results shown in Table 2, the adhesives for laminating metal foil and resin film of the present invention (Examples 1 to 10) exhibited normal T-shaped peel strength, T-shaped peel strength after immersion in an electrolytic solution solvent, and 85°C atmosphere. It can be seen that each of the T-shaped peel strengths of No. 1 is excellent.

On the other hand, an adhesive composition according to Comparative Example 2 using a polyurethane polyol (CA-2) containing neither a structural unit derived from the polyolefin polyol (a1) nor a structural unit derived from the polyester polyol (a2) is used. The peel strength is low after immersion in the electrolyte solvent and in an atmosphere of 85°C. With polyurethane polyols (CA-1) and (CA-3) that do not contain structural units derived from polyisocyanate (b) having a saturated cross-linked alicyclic structure, peel strength after immersion in an electrolyte solution solvent and under an atmosphere of 85°C. Is low.

According to the adhesive composition containing the polyurethane polyol (A) according to the present invention, an adhesive having excellent adhesive force between the metal foil and the resin film, and having electrolytic solution resistance and heat resistance Is obtained.

Claims (14)

A structural unit derived from a polyol containing at least one of a structural unit derived from the polyolefin polyol (a1) and a structural unit derived from the polyester polyol (a2);
A structural unit derived from polyisocyanate (b),
Have two or more hydroxyl groups,
The polyolefin polyol (a1) does not contain an alicyclic structure,
The polyester polyol (a2) has a structural unit derived from hydrogenated dimer acid and a structural unit derived from hydrogenated dimer diol,
The polyisocyanate (b) has a saturated crosslinked alicyclic structure,
Polyurethane polyol. The total content of the structural units derived from the polyolefin polyol (a1) and the structural units derived from the polyester polyol (a2) is 40% by mass or more and 95% by mass or less, and the content of the structural units derived from the polyisocyanate (b) is 5% by mass. % Or more and 60 mass% or less, The polyurethane polyol of Claim 1. The polyurethane polyol according to claim 1 or 2, comprising a structural unit derived from the polyolefin polyol (a1), and all bonds between carbon atoms contained in the polyolefin polyol (a1) are single bonds. The polyurethane polyol according to any one of claims 1 to 3, comprising a structural unit derived from a cyclic polyol (a3) having a cyclic hydrocarbon structure and two or more hydroxyl groups. The structural unit derived from a polyol comprises at least one of a structural unit derived from a polyolefin polyol (a1) and a structural unit derived from a polyester polyol (a2), and a structural unit derived from a cyclic polyol (a3). The described polyurethane polyol. The polyurethane polyol according to claim 4 or 5, wherein the cyclic polyol (a3) is a polyol having a saturated crosslinked alicyclic structure. The polyurethane polyol according to claim 4 or 5, wherein the cyclic polyol (a3) is a bisphenol compound. The polyurethane polyol according to any one of claims 4 to 7, wherein the content of the cyclic polyol (a3) is 5 to 60 parts by mass based on 100 parts by mass of the total amount of the polyolefin polyol (a1) and the polyester polyol (a2). A polyurethane polyol (A) according to any one of claims 1 to 8,
A curing agent (B) containing at least one of saturated aliphatic polyisocyanate, saturated alicyclic polyisocyanate, and aromatic polyisocyanate;
An adhesive composition comprising: The adhesive composition according to claim 9, wherein the amount of isocyanato groups contained in the curing agent (B) is 1 to 20 molar equivalents relative to 1 molar equivalent of hydroxyl group contained in the polyurethane polyol (A). The adhesive composition according to claim 9 or 10, further comprising a solvent (C). A first base material, a second base material, and an adhesive layer provided between the first base material and the second base material,
The said adhesive layer is a laminated material containing the hardened|cured material of the adhesive composition of any one of Claims 9-11. The laminate material according to claim 12, wherein the first base material is a metal foil, and the second base material is a resin film. A lithium ion secondary battery comprising the packaging material for a battery exterior, which comprises the laminate material according to claim 13.