JP2014185190A - Adhesive composition for battery exterior material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition being processable in dry lamination and being usable in application of a battery exterior material required to be excellent in electrolyte resistance and heat resistance.SOLUTION: An adhesive composition for a battery exterior material comprises a reactive functional group-containing styrenic elastomer (A) having at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group and a hydroxyl group; and a compound (B) having two or more isocyanate groups in 1 molecule.

Description

  The present invention relates to an adhesive composition for battery exterior materials that can be used for bonding an olefin-based resin film layer and an aluminum foil layer constituting a battery exterior material.

  Currently, electronic devices such as notebook computers, video cameras, and mobile phones are becoming smaller, lighter, and thinner. With the reduction in size and weight of electronic devices, there is a demand for higher performance, lighter weight, and improved movement performance of secondary storage batteries and capacitors for electronic devices. In order to meet such a demand, the mainstream of secondary storage batteries has been changed from a conventional lead storage battery to a lithium ion battery having a high energy density, and the development thereof is being carried out rapidly. Furthermore, a lithium ion battery having a high volume energy density that can be used for a power source of an electric vehicle or a hybrid vehicle, a high current charge / discharge cycle, and a charge / discharge cycle is being put into practical use.

Lithium-ion batteries use a compound containing lithium as the positive electrode material, and have a penetrability such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate together with carbon such as graphite and coke as the negative electrode material. In the solvent, an electrolyte layer made of an electrolytic solution in which a lithium salt such as LiPF ₆ or LiBF ₄ is dissolved as an electrolyte or a polymer gel impregnated with the electrolytic solution is included. When the solvent having such penetrating power passes through the film layer serving as a sealant, there is a problem that the laminate strength between the aluminum foil layer and the film layer is lowered and the electrolyte solution leaks out. Therefore, at present, in a battery case packaging material including a laminate in which a heat-resistant resin stretched film layer, an aluminum foil layer as an outer layer, and a thermoplastic resin unstretched film layer as an inner layer are sequentially laminated, the aluminum foil layer and the inner layer Batteries for battery cases that are bonded via an adhesive layer containing a polyolefin resin having a hydroxyl group or a carboxyl group and a polyfunctional isocyanate compound between the layers (see, for example, Patent Document 1 and Patent Document 2) have been developed. Has been. However, it is insufficient for use in heat-resistant battery exterior materials such as electric vehicles and hybrid vehicles.

  There are two methods of laminating the olefin resin film layer and the aluminum foil layer constituting the battery exterior material: a heat lamination method and a dry lamination method. The resin used in the heat lamination method is excellent in the electrolyte solution resistance required for the battery outer packaging material, but has a disadvantage of high cost and inferior moldability. On the other hand, the resin used in the dry lamination method is low in cost and excellent in moldability, but has a disadvantage inferior in electrolytic solution resistance.

Japanese Patent Laid-Open No. 2005-63685 JP 2010-92703 A

  An object of the present invention is to provide an adhesive composition for battery exterior materials that can be processed by a dry lamination method and can be used for battery exterior materials having excellent electrolytic solution resistance and heat resistance. .

  As a result of investigations to solve the above-mentioned problems, the present inventors have found that a reactive functional group-containing styrenic elastomer having at least one reactive functional group from the group consisting of a carboxyl group, an amino group, and a hydroxyl group. And it discovered that the adhesive composition which mix | blended the compound which has a 2 or more isocyanate group in 1 molecule can solve the said subject, and came to complete this invention.

  The present invention is shown by (1) to (11) below.

  (1) A reactive functional group-containing styrene elastomer (A) having at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group, and a hydroxyl group, and two or more isocyanate groups in one molecule An adhesive composition for battery outer packaging materials, comprising a compound (B) having the formula:

  (2) The molar ratio of the isocyanate groups of the compound (B) having two or more isocyanate groups in one molecule to the reactive functional groups of the reactive functional group-containing styrenic elastomer (A) is 0.5 to The adhesive composition for battery exterior materials according to (1), which is 10.0.

  (3) Adhesion for battery exterior materials according to (1) or (2), wherein the reactive functional group-containing styrenic elastomer (A) has a reactive functional group content of 0.01 to 4.0% by mass. Agent composition.

  (4) The adhesive composition for battery exterior materials according to any one of (1) to (3), wherein the weight average molecular weight of the reactive functional group-containing styrene elastomer (A) is 50,000 to 700,000.

  (5) Modified styrenic elastomer in which carboxyl group is introduced by modifying reactive functional group-containing styrenic elastomer (A) using ethylenically unsaturated carboxylic acid and / or ethylenically unsaturated carboxylic acid anhydride The adhesive composition for battery exterior materials according to any one of (1) to (4).

  (6) The adhesive composition for battery exterior materials according to any one of (1) to (5), further comprising a compound (C) having a functional group capable of reacting with the reactive functional group.

  (7) After reacting the reactive functional group-containing styrene elastomer (A) and the compound (C) at 40 to 80 ° C., compounding the compound (B) having two or more isocyanate groups in one molecule. (6) The adhesive composition for battery exterior materials as described in (6).

  (8) The molar ratio of the functional group of the compound (C) to the reactive functional group of the reactive functional group-containing styrenic elastomer (A) is 0.1 to 2.0 (6) or (7 ) Adhesive composition for battery outer packaging material according to.

  (9) A reactive functional group-containing styrene elastomer (A) having at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group, and a hydroxyl group, and a functional group capable of reacting with the reactive functional group The manufacturing method of the adhesive composition for battery exterior materials which mix | blends the compound (B) which has a 2 or more isocyanate group in 1 molecule, after making the compound (C) which has this react at 40-80 degreeC.

  (10) A battery exterior material obtained by using the adhesive composition for battery exterior materials according to any one of (1) to (8).

  (11) A battery exterior material obtained by laminating an olefin resin film and an aluminum foil using the adhesive composition for battery exterior materials according to any one of (1) to (8).

  ADVANTAGE OF THE INVENTION By this invention, the adhesive composition for battery exterior materials which can be processed by a dry lamination system and can be used for the battery exterior material use calculated | required the outstanding electrolyte solution resistance and heat resistance can be provided.

  Hereinafter, the present invention will be described in detail.

  The reactive functional group-containing styrenic elastomer (A) having at least one group out of the group consisting of a carboxyl group, an amino group, and a hydroxyl group used in the adhesive composition for battery exterior materials according to the present invention includes styrene. And block copolymers having structural units selected from ethylene, propylene, butylene, etc., such as styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers Polymer, styrene-butadiene diblock copolymer, styrene-isoprene diblock copolymer, styrene-ethylene-butylene diblock copolymer, styrene-ethylene-propylene diblock copolymer, styrene-ethylene-propylene-styrene block Copolymer A modified styrenic elastomer obtained by graft-polymerizing an ethylenically unsaturated carboxylic acid, its acid anhydride, an amino group-containing unsaturated compound, or a hydroxyl group-containing ethylenically unsaturated compound to a styrene-butadiene-butylene-styrene block copolymer or the like Can be mentioned. The content of styrene units in the reactive functional group-containing styrene elastomer (A) is 5 to 70% by mass and 30 to 50% by mass with respect to the reactive functional group-containing styrene elastomer (A). preferable. When the content of the styrene unit in the reactive functional group-containing styrene elastomer (A) is less than 5% by mass, the glass transition temperature of the reactive functional group-containing styrene elastomer (A) is lowered, so that the heat resistance is excellent. It becomes difficult to obtain an adhesive composition, and when it is more than 70% by mass, the adhesion to the substrate is lowered.

  The content of the reactive functional group-containing styrenic elastomer (A) in the adhesive composition for battery exterior materials is preferably 5 to 20% by mass, and more preferably 10 to 15% by mass. If the content of the reactive functional group-containing styrene-based elastomer (A) in the battery exterior material adhesive composition is less than 5% by mass, it will be difficult to develop adhesive performance, and if it is more than 20% by mass, the adhesive composition. The viscosity of the product tends to increase, and the coatability and workability tend to decrease.

  Examples of the ethylenically unsaturated carboxylic acid used for graft polymerization include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, and itaconic acid. These ethylenically unsaturated carboxylic acids may be used alone or in combination of two or more.

  Examples of the ethylenically unsaturated carboxylic acid anhydride used for graft polymerization include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like. These ethylenically unsaturated carboxylic acid anhydrides may be used alone or in combination of two or more.

  Examples of the amino group-containing unsaturated compound used for graft polymerization include 2-aminoethyl (meth) acrylate and 2-aminopropyl (meth) acrylate. These unsaturated amino compounds may be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing ethylenically unsaturated compound used for graft polymerization include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, N-methylol acrylamide, and ethylene glycol mono (Meth) acrylate, diethylene glycol (meth) acrylate, etc. are mentioned. These unsaturated hydroxyl group-containing compounds may be used alone or in combination of two or more.

  Although the graft modification was exemplified as a method of introducing the reactive functional group into the reactive functional group-containing styrene elastomer (A) used in the adhesive composition according to the present invention, the reaction was performed by other known methods such as a copolymerization method. It is also possible to introduce a functional group.

The reactive functional group content of the reactive functional group-containing styrene elastomer (A) is 0.1 to 4.0% by mass, more preferably 0.5 to 3.0% by mass, and still more preferably. Is 2.0-3.0 mass%. When the reactive functional group content is less than 0.1% by mass, the crosslinking density due to the isocyanate group-containing compound (B) is lowered, making it difficult to obtain an adhesive composition excellent in electrolytic solution resistance. When the amount is more than 4.0% by mass, the pot life of the battery exterior material adhesive composition is shortened, and the battery exterior material tends to be difficult to process. Here, the reactive functional group content refers to the carboxyl group (chemical formula: —COOH), amino in the reactive functional group-containing styrene elastomer with respect to the total mass of the reactive functional group-containing styrene elastomer (A). group (formula: -NH ₂₎ and a hydroxyl group (chemical formula: -OH) illustrates a ratio of the mass of a portion corresponding to a mass%.

  When the reactive functional group of the reactive functional group-containing styrene elastomer (A) of the present invention is a carboxylic acid, the acid value of the reactive functional group-containing styrene elastomer (A) is preferably 0.1 to 50. It is 0 mgKOH / g, More preferably, it is 0.5-30.0 mgKOH / g, More preferably, it is 1.0-10.0 mgKOH / g. When the acid value of the reactive functional group-containing styrenic elastomer (A) is lower than 0.1 mgKOH / g, an adhesive composition excellent in electrolytic solution resistance is obtained because the crosslinking density due to the isocyanate group-containing compound (B) decreases. When it becomes difficult to obtain and the acid value is higher than 50.0 mgKOH / g, the pot life of the adhesive composition for battery exterior materials is shortened, and it becomes difficult to process the battery exterior materials. As will be described later, when the reactive functional group-containing styrene elastomer (A) is reacted with the compound (C), the acid value of the compound obtained by the reaction is preferably 0.1 to 30.0 mgKOH. / G, more preferably 0.5 to 20.0 mgKOH / g, still more preferably 1.0 to 10.0 mgKOH / g. When the acid value of the compound resulting from the reaction is lower than 0.1 mg KOH / g, the crosslinking density due to the isocyanate group-containing compound (B) is lowered, making it difficult to obtain an adhesive composition excellent in electrolytic solution resistance, When the acid value is higher than 30.0 mgKOH / g, the pot life of the battery exterior material adhesive composition is shortened, making it difficult to process the battery exterior material. These acid values are values measured in accordance with JIS K0070. For example, measurement is performed as follows.

About 2 g of sample is precisely weighed into a 100 ml Erlenmeyer flask with a precision balance, and 10 ml of tetrahydrofuran is added to dissolve it. Further, 1 to 3 drops of BTB solution (bromothymol blue solution) is added as an indicator to this container, and the sample is sufficiently stirred until it becomes uniform. This is titrated with a 0.1N potassium hydroxide-ethanol solution, and when the indicator light yellow color changes to blue and the blue state of the solution continues for 30 seconds, the end point of neutralization is set. The value obtained from the result using the following calculation formula (1) is taken as the acid value of the sample.

  The weight average molecular weight of the reactive functional group-containing styrene-based elastomer (A) is 50,000 to 700,000, more preferably 100,000 to 500,000, and further preferably 150,000 to 400,000. When the weight average molecular weight is lower than 50,000, the peel strength under each condition decreases due to a decrease in the cohesive strength of the elastomer. It tends to be.

  The compound (B) having an isocyanate group is not particularly limited as long as it has two or more isocyanate groups in one molecule. Examples include aliphatic isocyanates such as hexamethylene diisocyanate, m- and p-phenylene diisocyanates, tolylene-2, 4- and -2, 6-diisocyanate, diphenylmethane-4, 4'-diisocyanate, diphenylene-4, 4 '. Aromatic isocyanates such as diisocyanate, 4,4′-diisocyanate-3,3′-dimethyldiphenyl, 3-methyl-diphenylmethane-4,4′-diisocyanate, diphenyl ether diisocyanate, and cyclohexane-2, 4- and −2. Alicyclic isocyanates such as 3-diisocyanate and isophorone diisocyanate, or isocyanurate-modified products and burette-modified products of these diisocyanate compounds. Among these, it is particularly preferable to use hexamethylene diisocyanate in terms of workability and pot life. Moreover, the compound which has an isocyanate group can be used individually or in mixture of 2 or more types.

  The molar ratio of the isocyanate group of the compound (B) having an isocyanate group to the reactive functional group of the reactive functional group-containing styrene elastomer (A) is 0.5 to 10.0, more preferably 1. It is 0-4.0, More preferably, it is 1.0-3.0. When the molar ratio of the isocyanate group of the compound (B) having an isocyanate group to the reactive functional group of the reactive functional group-containing styrene-based elastomer (A) is less than 0.5, the crosslink density decreases, so On the other hand, when it exceeds 10.0, the pot life is shortened, and the adhesion between the olefin-based resin film layer and the aluminum foil layer tends to be difficult.

  The compound (C) is crosslinked by adding the compound (C) having a functional group capable of reacting with the reactive functional group of the reactive functional group-containing styrenic elastomer (A) in the adhesive composition for battery exterior materials. Acting as a regulator, it becomes possible to control the pot life of the adhesive composition for battery exterior materials.

  Examples of the compound (C) capable of reacting with a carboxyl group include compounds having an isocyanate group, an epoxy group, a carbodiimide group, a hydroxyl group, a methylol group, a cyclic carbonate group, an aziridinyl group, an oxazoline group, and the like. As long as it has a group, there is no particular limitation. These can be used alone or in combination of two or more, and the use of a compound having an epoxy group and a carbodiimide group is desirable. In addition, when using the compound containing an isocyanate group as a compound (C), the isocyanate group contained in 1 molecule is one.

  Examples of the compound (C) capable of reacting with an amino group include compounds having an isocyanate group, an epoxy group, a carbodiimide group, an acetoacetoxy group, a methylol group, etc., and those having a group capable of reacting with an amino group. If there is, there is no particular limitation. These can be used alone or in combination of two or more, and the use of a compound having an epoxy group and a carbodiimide group is desirable. In addition, when using the compound containing an isocyanate group as a compound (C), the isocyanate group contained in 1 molecule is one.

  Examples of the compound (C) capable of reacting with a hydroxyl group include compounds having an isocyanate group, an epoxy group, a carbodiimide group, a methylol group, and the like. No. These can be used alone or in combination of two or more, and the use of a compound having an epoxy group and a carbodiimide group is desirable. In addition, when using the compound containing an isocyanate group as a compound (C), the isocyanate group contained in 1 molecule is one.

  The adhesive composition for battery exterior materials containing the compound (C) first reacts the reactive functional group-containing styrene elastomer (A) with the compound (C) having a functional group capable of reacting with the reactive functional group. It is manufactured by blending a compound (B) having two or more isocyanate groups in one molecule. Thereby, a part of the reactive functional group of the reactive functional group-containing styrenic elastomer (A) is protected by reacting with the compound (C), so the pot life of the adhesive composition for battery exterior materials can be reduced. It becomes possible to control.

  The reactive functional group-containing styrenic elastomer (A) and the compound (C) are preferably reacted at 40 to 80 ° C, more preferably 50 to 70 ° C. When the reaction temperature of the reactive functional group-containing styrene elastomer (A) and the compound (C) is lower than 40 ° C., the compound (C) protects the reactive functional group of the reactive functional group-containing styrene elastomer (A). In order to protect the reactive functional group of the reactive functional group-containing styrenic elastomer (A) at an amount higher than 80 ° C., the compound having an isocyanate group ( The part which crosslinks with B) tends to decrease and the physical properties tend to decrease.

  The compounding amount of the compound (C) capable of reacting with a carboxyl group, an amino group, or a hydroxyl group is such that the moles of the functional group of the compound (C) with respect to the reactive functional group of the reactive functional group-containing styrene elastomer (A). The ratio is 0.1 to 2.0, more preferably 0.1 to 1.0, and still more preferably 0.1 to 0.5. When the molar ratio of the functional group of the compound (C) to the reactive functional group of the reactive functional group-containing styrenic elastomer (A) is less than 0.1, it is difficult to extend the pot life. When it is more than 0.0, the electrolytic solution resistance and the heat resistance are lowered.

  The organic solvent used in the adhesive composition according to the present invention is not particularly limited as long as it can dissolve or disperse the reactive functional group-containing styrene-based elastomer (A). Among these, an organic solvent capable of dissolving the reactive functional group-containing styrene elastomer (A) is preferable. Examples include aromatic organic solvents such as toluene and xylene, and aliphatic organic solvents such as n-hexane. And alicyclic organic solvents such as cyclohexane and methylcyclohexane, and ketone organic solvents such as methyl ethyl ketone. These can be used individually or in mixture of 2 or more types.

  In the present invention, additives such as a reaction accelerator, a tackifier, and a plasticizer can be used in combination with the adhesive composition. These additives can be used alone or in combination of two or more.

  Examples of the reaction accelerator for promoting the reaction between the reactive functional group-containing styrene elastomer (A) and the compound (B) having an isocyanate group include dioctyltin dilaurate, dioctyltin diacetate and tertiary amine which are organotin compounds. 2,4,6-tris (dimethylaminomethyl) phenol, dimethylaniline, dimethylparatoluidine, N, N-di (β-hydroxyethyl) -P-toluidine and the like. These reaction accelerators can be used alone or in combination of two or more.

  Examples of the tackifier include petroleum resin-based and rosin-based, rosin derivative-based, terpene-based, terpene derivative-based natural resin-based tackifiers. These tackifiers can be used alone or in combination of two or more.

  As the plasticizer, liquid rubber such as polyisoprene and polybutene, dibutyl phthalate, dioctyl phthalate, texanol, DBE (dibasic acid ester) and the like are appropriately used.

  The battery exterior material is a laminate in which an outer layer, an aluminum foil layer, and an inner layer are sequentially laminated. The outer layer is not particularly limited in order to ensure good moldability, puncture resistance and dimensional stability against heat during thermal bonding as an exterior material, but it is a polyamide film or a polyester film stretched in a biaxial direction. A heat-resistant resin stretched film made of, etc. is used. The inner layer has excellent chemical resistance against highly corrosive electrolytes used in lithium ion batteries, etc., and can provide heat sealability and case sealability to the exterior material An unstretched film made of a thermoplastic resin such as polyethylene, polypropylene, maleic acid-modified polypropylene, ethylene-acrylate copolymer or ionomer resin is used. Both the outer and inner film layers may be a single layer or multiple layers. In addition, polyvinylidene chloride, vinylidene chloride-vinyl chloride co-polymerized on the surface side of the heat-resistant resin stretched film of the outer layer so that there is no risk of poor appearance or corrosion even if electrolyte solution adheres to the outermost side of one side of the aluminum foil. At least one coating layer selected from a coalescence, maleic anhydride-modified polypropylene, polyester resin, epoxy resin, phenol resin, fluororesin, cellulose ester, urethane resin, and acrylic resin may be formed. The adhesive composition for battery exterior materials of this invention is used suitably for bonding of the olefin resin film layer and aluminum foil layer of the battery exterior material which has electrolyte solution resistance and heat resistance.

  Although the adhesive composition for battery exterior materials of this invention is used suitably for battery exterior materials which have electrolyte solution resistance and heat resistance, it is not specifically limited to such a use. For example, when the covering film is bonded to the lead terminal of the battery, the lead terminal and the resin film can be bonded using the adhesive composition of the present invention.

  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,% in an Example and a comparative example is a mass reference | standard.

Example 1
In a 1 liter separable flask equipped with a stirrer, a thermometer, and a reflux condenser, a maleic acid-modified styrene-ethylene-butylene-styrene block copolymer a (maleic acid modification rate: 3.0 mass) as a styrene-based elastomer having a carboxyl group %, Styrene unit content 30% by mass, carboxyl group content 2.3% by mass, acid value 25 mg KOH / g, weight average molecular weight 300,000) 150 g, toluene 1033 g, methyl ethyl ketone 67 g, Main agent A (viscosity 400 mPa · s: BM viscometer, 60 rotations, 30 ° C.) was prepared. To 100 g of main agent A, 1.5 g of Duranate TKA-100 (produced by Asahi Kasei Chemicals Corporation, hexamethylene diisocyanate, isocyanate group content 21.7% by mass), which is a compound containing isocyanate, is added and mixed thoroughly. The performance of the adhesive composition of Example 1 was evaluated.

(Example 2)
Except having changed Duranate TKA-100 into 0.5 g, operation similar to Example 1 was performed and the adhesive composition of Example 2 was obtained.

(Example 3)
Except having changed Duranate TKA-100 into 0.7 g, operation similar to Example 1 was performed and the adhesive composition of Example 3 was obtained.

Example 4
The adhesive composition of Example 4 was obtained by performing the same operation as in Example 1 except that Duranate TKA-100 was changed to 10.0 g.

(Example 5)
The adhesive composition of Example 5 was obtained by performing the same operation as in Example 1 except that Duranate TKA-100 was changed to 13.0 g.

(Example 6)
Maleic acid-modified styrene-ethylene-butylene-styrene block copolymer a was converted to maleic acid-modified styrene-ethylene-butylene-styrene block copolymer b (maleic acid modification rate 5.5% by mass, styrene unit content 30% by mass, By changing the carboxyl group content to 4.3 mass%, the acid value of 50 mgKOH / g, and the weight average molecular weight of 30,000, the same operation as in the main agent preparation method of Example 1 was performed, and the main agent B (viscosity 300 mPa · s: BM) Type viscometer, 60 rotations, 30 ° C.). The adhesive composition of Example 6 was obtained by adding 3.0 g of Duranate TKA-100 to 100 g of the main agent B and mixing them well.

(Example 7)
Maleic acid-modified styrene-ethylene-butylene-styrene block copolymer a was converted to maleic acid-modified styrene-ethylene-butylene-styrene block copolymer c (maleic acid modification ratio 1.0%, styrene unit content 35% by mass, carboxyl The base content was 0.78% by mass, the acid value was 10 mg KOH / g, and the weight average molecular weight was 600,000. The same operation as in the main agent preparation method of Example 1 was performed, and the main agent C (viscosity 500 mPa · s: BM type) Viscometer, 60 rotations, 30 ° C.). To 100 g of the main agent C, 0.5 g of Duranate TKA-100 was added and mixed well to obtain an adhesive composition of Example 7.

(Example 8)
In a 1-liter separable flask equipped with a stirrer, a thermometer, and a reflux condenser, a maleic acid-modified styrene-ethylene-butylene-styrene block copolymer a (maleic acid modification rate 3.0%) as a styrene-based elastomer having a carboxyl group Styrene unit content 30% by mass, carboxyl group content 2.3% by mass, acid value 25 mgKOH / g, weight average molecular weight 300,000) 150 g, toluene 1033 g, methyl ethyl ketone 67 g were charged, and the mixture was raised to 60 ° C. and dissolved. And 20.09 g of compound K having a carbodiimide group (Nisshinbo Chemical Co., Ltd., product name: Carbodilite V-05, active ingredient 100%, carbodiimide equivalent 262 (chemical formula amount per 1 mol of carbodiimide group)) and 147 g of toluene were added. Stir at 60 ° C for 3 hours This produced the main agent A1 (viscosity 500 mPa · s: BM viscometer, 60 rotations, 30 ° C.). 1.5 g of Duranate TKA-100, which is a compound containing an isocyanate group, was added to 100 g of the main agent A1 and mixed well to evaluate the performance as an adhesive composition of Example 8.

Example 9
The same operation as in the method for preparing the main agent of Example 8 was performed except that 4.02 g of the compound K having a carbodiimide group was added and 29.5 g of toluene added together with the compound K having a carbodiimide group was changed to 29.5 g. The main agent A2 (viscosity 450 mPa · s: BM viscometer, 60 revolutions, 30 ° C.) was produced. An adhesive composition of Example 9 was obtained by adding 1.5 g of Duranate TKA-100 to 100 g of the main agent A2 and mixing well.

(Example 10)
The procedure was the same as in the method for producing the main agent of Example 8, except that 50.22 g of the compound K having a carbodiimide group was added and the toluene added together with the compound K having a carbodiimide group was changed to 368.28 g. The main agent A3 (viscosity 400 mPa · s: BM viscometer, 60 revolutions, 30 ° C.) was produced. An adhesive composition of Example 10 was obtained by adding 1.5 g of Duranate TKA-100 to 100 g of the main agent A3 and mixing them well.

(Comparative Example 1)
In place of the reactive functional group-containing styrene elastomer a having a carboxyl group, 150 g of unmodified styrene-ethylene-butylene-styrene block copolymer d (weight average molecular weight 300,000) is used. The same operation was performed to prepare a base agent D (viscosity 300 mPa · s: BM viscometer, 60 revolutions, 30 ° C.), and an adhesive composition of Comparative Example 1 was obtained. In Comparative Example 1, unlike Example 1, Duranate TKA-100 is not used.

(Comparative Example 2)
To 100 g of the main agent D prepared in Comparative Example 1, 1.5 g of Duranate TKA-100 was added and mixed well to obtain an adhesive composition of Comparative Example 2.

(Comparative Example 3)
Instead of the reactive functional group-containing styrenic elastomer a having a carboxyl group, a maleic acid-modified polypropylene resin e (maleic acid modification rate 1.5% by mass, carboxyl group content 1.2% by mass, acid value 12 mgKOH / g, 150 g of a weight average molecular weight 150,000) was used, and the same operation as the main agent preparation method of Example 1 was performed to prepare a main agent E (viscosity 400 mPa · s: BM viscometer, 60 rotations, 30 ° C.). To 100 g of the main agent E, 1.5 g of Duranate TKA-100 was added and mixed well to obtain an adhesive composition of Comparative Example 3.

(Comparative Example 4)
The adhesive composition of Comparative Example 4 was prepared in the same manner as in Example 1 except that 1.5 g of Denacol EX-810 (manufactured by Nagase ChemteX Corporation), which is an epoxy compound, was used instead of Duranate TKA-100. Got.

  Using the adhesive compositions obtained in the above Examples and Comparative Examples, the following property measurement and physical property evaluation were performed. The results are shown in Tables 1 and 2.

<Property measurement>
(1) Nonvolatile content It calculated by measuring the mass of the residue, after drying the reactive functional group containing styrene-type elastomer adhesive composition which has a carboxyl group for 5 hours at 110 degreeC.

(2) Viscosity The viscosity was measured at 60 rpm using a BM viscometer under the condition of 30 ° C.

(3) Acid value About 2 g of each sample is precisely weighed in a 100 ml Erlenmeyer flask with a precision balance, and 10 ml of tetrahydrofuran is added to dissolve it. Further, 1 to 3 drops of BTB solution (bromothymol blue solution) is added as an indicator to this container, and the sample is sufficiently stirred until it becomes uniform. This is titrated with a 0.1N potassium hydroxide-ethanol solution, and when the indicator light yellow color changes to blue and the blue state of the solution continues for 30 seconds, the end point of neutralization is set. The value obtained from the result using the above formula (1) is defined as the acid value of the main agent.

(4) Molecular weight measurement Shodex GPC System-11 manufactured by Showa Denko KK (column temperature: 40 ° C., sample concentration and solvent: a sample diluted to 0.2% with tetrahydrofuran, flow rate: 2.0 ml / min, eluent: tetrahydrofuran, detector: packed column Shodex GPC KF-806L manufactured by Showa Denko KK).

<Preparation of test piece>
Base material: Aluminum-iron alloy aluminum foil (AA standard 8079, O material, thickness 40 μm) / unstretched polypropylene film (thickness 40 μm)
Application amount: Pre-drying applied to the surface of the aluminum foil so that the thickness after drying becomes 2 μm: 80 ° C. × 10 seconds Pressing condition: Roll press 80 ° C. × 25 kg / cm ² × 1 time curing: 60 ° C. × 1 Daily processing method: applied to the aluminum foil surface so that the thickness after drying becomes 2 μm, dried at 80 ° C. for 10 seconds with a dryer, and then bonded with an unstretched polypropylene film using a roll press, at 60 ° C. Cured for 1 day under atmosphere.

<Measurement of physical properties>
(1) Normal T-shaped peel strength A test piece was cut into a width of 15 mm, and a 90 ° peel strength was obtained at a peel rate of 100 mm / min using Tensilon (made by Orientec Co., Ltd.) in an atmosphere of 23 ° C. × 50% RH. It was measured.

(2) T-peel strength after immersion in electrolyte solution Cut the test piece into 15 mm width, soak in electrolyte solution propylene carbonate / diethyl carbonate (50/50 parts by weight), and leave for 1 day in an atmosphere of 80 ° C. In a 23 ° C. × 50% RH atmosphere, 90 ° peel strength was measured at a peel rate of 100 mm / min using Tensilon (manufactured by Orientec Co., Ltd.).

(3) Peel strength in an 80 ° C. atmosphere A test piece was cut to a width of 15 mm, and autograph AG-X (manufactured by Shimadzu Corporation) was used in an 80 ° C. atmosphere at a peel rate of 100 mm / min. The peel strength was measured.

(4) Pot life time Under a 23 ° C. × 50% RH atmosphere, a compound of a reactive functional group-containing styrene elastomer (A) having a carboxyl group and a compound (B) having an isocyanate group was mixed with a TK homomixer (specialized mechanized With TK ROBO MICS, manufactured by Kogyo Co., Ltd., the mixture was stirred at 500 rpm for 5 minutes, and the time until it could not be processed under the test piece preparation conditions was measured.

Calculation of isocyanate group / carboxyl group molar ratio and carbodiimide group / carboxyl group molar ratio, molar amount of isocyanate group, and molar amount of carbodiimide group in the above Examples and Comparative Examples The method is shown in the following calculation formulas (2) to (4).

  The isocyanate group content referred to here is the ratio of the mass of the portion corresponding to the isocyanate group (chemical formula: —NCO) of the compound having an isocyanate group to the total mass of the compound having an isocyanate group expressed in mass%. It is.

  Since the adhesive composition of the present invention can be processed by a dry lamination method and has excellent electrolytic solution resistance and heat resistance, it is useful as an adhesive composition that can be used for battery exterior materials.

Claims (11)

A reactive functional group-containing styrene elastomer (A) having at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group, and a hydroxyl group, and a compound having two or more isocyanate groups in one molecule The adhesive composition for battery exterior materials containing (B). The molar ratio of the isocyanate group of the compound (B) having two or more isocyanate groups in one molecule is 0.5 to 10.0 with respect to the reactive functional group of the reactive functional group-containing styrenic elastomer (A). The adhesive composition for battery exterior materials according to claim 1. The adhesive composition for battery exterior materials according to claim 1 or 2, wherein the reactive functional group-containing styrenic elastomer (A) has a reactive functional group content of 0.01 to 4.0 mass%. The adhesive composition for battery exterior materials according to any one of claims 1 to 3, wherein the reactive functional group-containing styrene elastomer (A) has a weight average molecular weight of 50,000 to 700,000. The reactive functional group-containing styrenic elastomer (A) is a modified styrenic elastomer having a carboxyl group introduced by modification using an ethylenically unsaturated carboxylic acid and / or an ethylenically unsaturated carboxylic acid anhydride. Item 5. The adhesive composition for battery exterior materials according to any one of Items 1 to 4. Furthermore, the adhesive composition for battery exterior materials in any one of Claims 1-5 containing the compound (C) which has a functional group which can react with the said reactive functional group. After reacting the reactive functional group-containing styrene elastomer (A) and the compound (C) at 40 to 80 ° C., it is obtained by blending the compound (B) having two or more isocyanate groups in one molecule. The adhesive composition for battery exterior materials of Claim 6. The molar ratio of the functional group capable of reacting with the reactive functional group of the compound (C) to the reactive functional group of the reactive functional group-containing styrenic elastomer (A) is 0.1 to 2.0. Item 8. The adhesive composition for battery exterior materials according to Item 6 or 7. A reactive functional group-containing styrene elastomer (A) having at least one reactive functional group selected from the group consisting of a carboxyl group, an amino group, and a hydroxyl group, and a compound having a functional group capable of reacting with the reactive functional group A method for producing an adhesive composition for battery exterior materials, in which (C) is reacted at 40 to 80 ° C., and then compound (B) having two or more isocyanate groups in one molecule is blended. The battery exterior material obtained using the adhesive composition for battery exterior materials in any one of Claims 1-8. The battery cladding | exterior_material obtained by bonding an olefin resin film and aluminum foil using the adhesive composition for battery cladding | exterior_materials in any one of Claims 1-8.