WO2017030024A1

WO2017030024A1 - Packaging material for lithium-ion battery

Info

Publication number: WO2017030024A1
Application number: PCT/JP2016/073141
Authority: WO
Inventors: 坂田　秀行; 健二柏原
Original assignee: 東洋紡株式会社
Priority date: 2015-08-19
Filing date: 2016-08-05
Publication date: 2017-02-23
Also published as: JPWO2017030024A1; TW201710074A; JP6733674B2

Abstract

The objective of the present invention is to provide: a packaging material for a battery, said packaging material having excellent resistance against electrolyte solutions, and having no problems due to limitations of pot life or production conditions; and a battery in which said packaging material is used. Specifically, the present invention provides a packaging material for a battery, said packaging material being formed by laminating, in the following order, a barrier layer, an adhesion layer, and a sealant layer, wherein the packaging material is characterized in that the adhesion layer includes: an acid-modified polyolefin (A) having an acid value of 5-50mg KOH/g resin; and a reaction product of a glycidyl amine type epoxy resin (B1) and a glycidyl ether type epoxy resin (B2).

Description

Lithium-ion battery packaging materials

The present invention relates to a battery packaging material and a battery using the packaging material.

In recent years, lithium batteries that can be made ultra-thin and miniaturized have been actively developed as batteries for use in mobile terminal devices such as personal computers and mobile phones, video cameras, and satellites. This lithium battery packaging material, unlike metal cans that have been used in the past, is a laminate having a structure such as a base layer / barrier layer / sealant layer because of its advantage of being lightweight and allowing the battery shape to be freely selected. Has come to be used.

Lithium battery is impregnated with electrolyte solution or lithium electrolyte dissolved in aprotic solvent such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate together with positive electrode material and negative electrode material as battery contents And an electrolyte layer made of a polymer gel. When such a strong permeable solvent passes through the sealant layer, the laminate strength between the aluminum foil layer and the sealant layer is lowered to cause delamination, and finally the electrolyte leaks. Lithium salt, which is the battery electrolyte, uses LiPF ₆ , LiBF _4, etc., but these salts generate hydrofluoric acid by hydrolysis with water, and the hydrofluoric acid corrodes the aluminum foil. By doing so, the laminate strength is lowered. Thus, the battery packaging material needs to have resistance to the electrolyte.

Furthermore, it is necessary for lithium batteries to have more severe resistance, assuming that they are used in various environments. For example, when used in a mobile device, liquid leakage resistance in a high temperature environment of 60 to 70 ° C. such as in a car is required. In addition, water resistance is also required to prevent moisture from entering, assuming that it was used in a mobile phone and accidentally dropped into water.

Under such circumstances, various packaging materials for lithium batteries with improved electrolyte resistance have been proposed (see, for example, Patent Documents 1 to 6).

Japanese Patent Laid-Open No. 2001-243928 JP 2004-42477 A JP 2004-142302 A JP 2009-238475 A JP 2010-086744 A Japanese Patent No. 5670803

However, the proposed packaging material for lithium batteries is still insufficient in terms of resistance to electrolyte. Moreover, even if the improvement of the electrolytic solution resistance was large, there was a problem.

Specifically, it is difficult to ensure pot life after the curing agent is blended with the pot life and the resistance to electrolyte solution (Patent Document 1), and the adhesive layer is an extruded resin. (2) Patent Documents 2, 3 and 5 cause the heat shrinkage of the polyolefin base material to be pasted together, and because the polyolefin base material is aqueous, the drying time is long and the production conditions are limited (Patent Documents 4 and 6). , Etc. were seen.

An object of the present invention is to provide a battery packaging material excellent in electrolytic solution resistance and a battery using the packaging material without problems such as pot life and production condition limitations.

In order to achieve the above-mentioned problems, the present inventors have intensively studied and have come up with the following inventions.

A battery packaging material in which a barrier layer, an adhesive layer and a sealant layer are laminated in this order, wherein the adhesive layer is an acid-modified polyolefin (A) having an acid value of 5 to 50 mgKOH / g-resin, a glycidylamine type A battery packaging material comprising a reaction product of an epoxy resin (B1) and a glycidyl ether type epoxy resin (B2).

The glycidylamine type epoxy resin (B1) is preferably an epoxy resin having two or more glycidyl groups in one molecule.

The glycidylamine type epoxy resin (B1) is preferably a compound represented by the general formula (1).

(In the general formula (1), R is an aryl group which may have a substituent, and A1 and A2 are each independently an alkylene group which may have a substituent having 1 to 5 carbon atoms, m is 1 or 2, and n is 1 or 2.)
The glycidyl ether type epoxy resin (B2) is preferably an epoxy resin having two or more glycidyl groups in one molecule and containing no nitrogen atom.

The adhesive layer comprises 0.01 to 20 parts by mass of glycidylamine type epoxy resin (B1) and 1 to 20 parts by mass of glycidyl ether type epoxy resin (B2) with respect to 100 parts by mass of acid-modified polyolefin (A). It is preferable to contain a reactant.

A solution containing acid-modified polyolefin (A), glycidylamine type epoxy resin (B1), glycidyl ether type epoxy resin (B2) and organic solvent (C) is applied to the surface of the barrier layer and dried to form an adhesive layer. Then, the method for producing a battery packaging material according to any one of the above, wherein a sealant layer is laminated on the surface of the adhesive layer.

A battery using the battery packaging material described above.

The organic solvent (C) is a mixed liquid of a solvent (C1) and a solvent (C2), and the solvent (C1) is composed of an aromatic hydrocarbon, an aliphatic hydrocarbon, an alicyclic hydrocarbon, and a halogenated hydrocarbon. One or more solvents selected from the group consisting of one or more solvents selected from the group consisting of alcohol solvents, ketone solvents, ester solvents and glycol ether solvents. It is preferable that the solvent (C1) / solvent (C2) = 50 to 97/50 to 3 (mass ratio).

The battery packaging material of the present invention uses a composition comprising a specific resin and a specific cross-linking agent in the battery packaging material in which a barrier layer, an adhesive layer, and a sealant layer are sequentially laminated. For this reason, when it uses as a packaging material of a battery, the outstanding electrolyte solution resistance is exhibited, As a result, the lifetime of a battery extends, the safety | security in handling also increases, and industrial utility value is very high.

Further, the production method according to the present invention is preferable in that it can easily adjust the basis weight of the adhesive layer, can easily control the thickness, and is a solvent system, so that the drying conditions are not limited and the packaging material can be produced efficiently. .

Hereinafter, embodiments of the present invention will be described in detail.

<< Adhesive layer >>
The adhesive layer must contain a reaction product of an acid-modified polyolefin (A) having an acid value of 5 to 50 mgKOH / g-resin, a glycidylamine type epoxy resin (B1), and a glycidyl ether type epoxy resin (B2). is there. The adhesive layer is not particularly limited, but an adhesive composition containing an acid-modified polyolefin (A), a glycidyl amine type epoxy resin (B1), a glycidyl ether type epoxy resin (B2) and an organic solvent (C) is used as a barrier layer. A layer of an adhesive composition obtained by applying and drying on the surface to remove the organic solvent (C) and then aging (curing reaction) is preferable.

The thickness of the adhesive layer is not particularly limited, but is preferably 1 μm or more, more preferably 2 μm or more, further preferably 3 μm or more, preferably 20 μm or less, more preferably 15 μm or less, and further preferably 10 μm or less. If the thickness is less than the thickness, adhesiveness may not be expressed. If the thickness exceeds the thickness, the workability may be reduced, and in addition, the efficiency may be reduced in terms of manufacturing cost.

<Acid-modified polyolefin (A)>
The acid-modified polyolefin (A) used in the present invention is not limited, but at least one of polyethylene, polypropylene, and propylene-α-olefin copolymer includes at least α, β-unsaturated carboxylic acid and acid anhydride thereof. What is obtained by grafting 1 type is preferable.

The propylene-α-olefin copolymer is a copolymer in which α-olefin is copolymerized mainly with propylene. As the α-olefin, for example, ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate or the like can be used. Of these α-olefins, ethylene and 1-butene are preferred. The ratio of the propylene component to the α-olefin component of the propylene-α-olefin copolymer is not limited, but the propylene component is preferably 50 mol% or more, and more preferably 70 mol% or more.

Examples of at least one of α, β-unsaturated carboxylic acid and acid anhydrides thereof include maleic acid, itaconic acid, citraconic acid, and acid anhydrides thereof. Among these, acid anhydrides are preferable, and maleic anhydride is more preferable. Specific examples include maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, maleic anhydride-modified propylene-ethylene-butene copolymer, and the like. These acid-modified polyolefins can be used alone or in combination of two or more.

The acid value of the acid-modified polyolefin (A) is required to be 5 mg KOH / g-resin or more, preferably 10 mg KOH / g-resin or more, from the viewpoint of pot life and adhesion between the barrier layer and the sealant layer. More preferably 14 mg KOH / g-resin or more, still more preferably 16 mg KOH / g-resin or more, particularly preferably 18 mg KOH / g-resin or more, most preferably 20 mg KOH / g-resin or more. . If it is less than the above value, the compatibility with the epoxy resin is low, the adhesive strength may not be exhibited, the crosslinking density is low, and the chemical resistance may be poor. The upper limit needs to be 50 mgKOH / g-resin or less, preferably 48 mgKOH / g-resin or less, more preferably 46 mgKOH / g-resin or less, still more preferably 44 mgKOH / g-resin or less. Preferably it is 42 mgKOH / g-resin or less, Most preferably, it is 40 mgKOH / g-resin or less. When the above value is exceeded, the viscosity and stability of the solution may decrease, and the pot life may decrease. Furthermore, it is not preferable because the production efficiency is also lowered.

The weight average molecular weight (Mw) of the acid-modified polyolefin (A) is preferably in the range of 40,000 to 180,000. More preferably, it is in the range of 50,000 to 160,000, more preferably in the range of 60,000 to 150,000, particularly preferably in the range of 70,000 to 140,000, and most preferably 80. , 13,000 to 130,000. If it is less than the above value, the cohesive force becomes weak and the adhesiveness may be inferior. On the other hand, when the above value is exceeded, there may be a problem in operability when bonding due to low fluidity. If it is in the said range, since hardening reaction with an epoxy resin is utilized, it is preferable.

The acid-modified polypropylene (A) is preferably a crystalline acid-modified polypropylene (A). The crystalline acid-modified polyolefin (A) referred to in the present invention means that the temperature is raised from −100 ° C. to 250 ° C. at 20 ° C./min using a differential scanning calorimeter (DSC). It refers to those showing a melting peak.

It is advantageous to make the acid-modified polyolefin crystalline, because it has a stronger cohesive force and superior adhesion and chemical resistance than amorphous.

The melting point (Tm) of the acid-modified polyolefin (A) is preferably in the range of 50 ° C to 120 ° C. More preferably, it is in the range of 60 ° C to 100 ° C, and most preferably in the range of 70 ° C to 90 ° C. If it is less than the above value, the cohesive force derived from crystals becomes weak, and the adhesiveness and chemical resistance may be inferior. On the other hand, when the above value is exceeded, the solution stability and fluidity are low, and there may be a problem in operability when bonding.

The heat of fusion (ΔH) of the acid-modified polyolefin (A) is preferably in the range of 5 J / g to 60 J / g. A range of 10 J / g to 50 J / g is more preferable, and a range of 20 J / g to 40 J / g is most preferable. If it is less than the above value, the cohesive force derived from crystals becomes weak, and the adhesiveness and chemical resistance may be inferior. On the other hand, when the above value is exceeded, the solution stability and fluidity are low, and there may be a problem in operability when bonding.

The method for producing the acid-modified polyolefin (A) is not particularly limited, and for example, radical graft reaction (that is, generating radical species for the polymer to be the main chain, and using the radical species as a polymerization initiation point, the unsaturated carboxylic acid and Examples include a reaction of graft polymerization of an acid anhydride.

Although it does not specifically limit as a radical generator, It is preferable to use an organic peroxide. The organic peroxide is not particularly limited, but di-tert-butyl peroxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxy- Peroxides such as 2-ethylhexanoate, tert-butyl peroxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide, lauroyl peroxide; azobisisobutyronitrile, azobisisopropionitrile, etc. And azonitriles

<Glycidylamine type epoxy resin (B1)>
The glycidylamine type epoxy resin (B1) used for this invention will not be specifically limited if it is an epoxy resin which has one glycidyl group in 1 molecule. It is preferable to have two or more glycidyl groups in one epoxy resin molecule, more preferably three or more glycidyl groups in one molecule of epoxy resin, and four or more glycidyl groups in one molecule of epoxy resin. More preferably, it has.

Also, the glycidylamine type epoxy resin (B1) is preferable because the chemical resistance is further improved by using a compound represented by the following general formula (1).

In general formula (1), R is an aryl group which may have a substituent, and preferably a phenyl group which may have a substituent. The substituent of the aryl group is not particularly limited, and examples thereof include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a hydroxyl group, an amino group, a glycidyl group, a glycidylamino group, and a glycidyl ether group. Can be mentioned. A1 and A2 are each independently a linear alkylene group which may have a substituent having 1 to 5 carbon atoms, preferably 4 or less, more preferably 3 or less, and still more preferably Is 2 or less. Although it does not specifically limit as a substituent of the said alkylene group, A C1-C5 alkyl group, a C1-C5 alkoxy group, or an amino group is mentioned. m is 1 or 2, and n is 1 or 2. Preferably, either m or n is 2, more preferably m and n are both 2.

Specific examples of the glycidylamine type epoxy resin (B1) are not particularly limited, but include tetraglycidyldiaminodiphenylmethane, triglycidylparaaminophenol, tetraglycidylbisaminomethylcyclohexanone, N, N, N ′, N′-tetraglycidyl-m. -Glycidylamine type such as xylenediamine. Of these, N, N, N ′, N′-tetraglycidyl-m-xylenediamine is preferred. These glycidylamine type epoxy resins (B1) can be used alone or in combination of two or more.

The blending amount of the glycidylamine type epoxy resin (B1) is preferably 0.01 parts by mass or more and more preferably 0.05 parts by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A). The content is more preferably 0.1 parts by mass or more, particularly preferably 1 part by mass or more, and most preferably 2 parts by mass or more. Further, it is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, further preferably 16 parts by mass or less, particularly preferably 14 parts by mass or less, and 12 parts by mass or less. Most preferably it is. If it is less than the above range, the catalytic action is not exhibited, and there are cases where adhesion at 80 ° C. or lower and aging adhesion and chemical resistance are low. Above the range, the crosslinking reaction proceeds excessively, the rigidity becomes high, and the adhesiveness tends to be lowered. Further, the crosslinking reaction tends to proceed during storage of the adhesive composition solution, and the pot life tends to be reduced.

<Glycidyl ether type epoxy resin (B2)>
The glycidyl ether type epoxy resin (B2) used for this invention will not be specifically limited if it is an epoxy resin which has a glycidyl ether group in a molecule | numerator. Preferably, it is an epoxy resin having two or more glycidyl groups in one molecule of the epoxy resin, and more preferably an epoxy resin having two or more glycidyl groups in one molecule of the epoxy resin and containing no nitrogen atom. .

The blending amount of the glycidyl ether type epoxy resin (B2) is preferably 1 part by mass or more, more preferably 2 parts by mass or more, with respect to 100 parts by mass of the acid-modified polyolefin (A). More preferably, it is more preferably 4 parts by mass or more, and most preferably 5 parts by mass or more. Further, it is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, further preferably 16 parts by mass or less, particularly preferably 14 parts by mass or less, and 12 parts by mass or less. Most preferably it is. By setting it in the above range, excellent adhesiveness and chemical resistance can be expressed.

Specific examples of the glycidyl ether type epoxy resin (B2) are not particularly limited, and examples thereof include a phenol novolac type epoxy resin and a cresol novolac type epoxy resin. From the viewpoint of adhesion to the barrier layer and chemical resistance. preferable. These glycidyl ether type epoxy resins (B2) can be used alone or in combination of two or more.

In the present invention, two types of epoxy resins, the glycidylamine type epoxy resin (B1) and the glycidyl ether type epoxy resin (B2), are used in combination as essential components. By using the glycidylamine type epoxy resin (B1) and the glycidyl ether type epoxy resin (B2) in combination, excellent adhesiveness and chemical resistance can be expressed. That is, the glycidylamine type epoxy resin (B1) has a reaction and curing action between the acid-modified polyolefin (A) and the glycidyl ether type epoxy resin (B2). Furthermore, the glycidylamine type epoxy resin (B1) includes acid-modified polyolefin (A) and glycidylamine type epoxy resin (B1), glycidylamine type epoxy resin (B1), glycidyl ether type epoxy resin (B2), and glycidylamine. Type epoxy resin (B1) and glycidyl ether type epoxy resin (B2) have a reaction and curing catalytic action, so that they can be combined to bond at 80 ° C. or lower, adhesion to the barrier layer during aging, and chemical resistance Property can be improved.

The total amount of the glycidylamine type epoxy resin (B1) and the glycidyl ether type epoxy resin (B2) is preferably 2 to 40 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin (A). The amount is more preferably 20 parts by mass, and most preferably 10 to 16 parts by mass. If it is less than the above range, a sufficient curing effect may not be obtained and the adhesiveness and chemical resistance may be low, and if it exceeds the above range, it is not preferable from the viewpoint of reduction in adhesiveness between the pot life and the sealant layer and cost.

The blending amount of the glycidylamine type epoxy resin (B1) is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, and most preferably 3 to 10% by mass of the entire epoxy resin. . If the blending amount is less than the above, the catalytic action does not appear and the adhesion and chemical resistance in low temperature bonding and aging may be low. If it exceeds the above, the crosslinking reaction proceeds excessively and the rigidity becomes high. The adhesiveness tends to decrease. Further, the crosslinking reaction tends to proceed during storage of the adhesive composition solution, and the pot life tends to be reduced.

Other epoxy resins can be used in combination as the epoxy resin used in the present invention. For example, glycidyl ester type such as hexahydrophthalic acid glycidyl ester, dimer acid glycidyl ester, triglycidyl isocyanurate, or 3,4-epoxycyclohexylmethylcarboxylate, epoxidized polybutadiene, epoxidized soybean oil, etc. Group epoxides and the like, and may be used alone or in combination of two or more.

<Organic solvent (C)>
The organic solvent (C) used in the present invention is not particularly limited as long as it dissolves the acid-modified polyolefin (A), the glycidylamine type epoxy resin (B1), and the glycidyl ether type epoxy resin (B2). Specifically, for example, aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as hexane, heptane, octane and decane, and alicyclic carbons such as cyclohexane, cyclohexene, methylcyclohexane and ethylcyclohexane Halogenated hydrocarbons such as hydrogen, trichloroethylene, dichloroethylene, chlorobenzene, chloroform, alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, phenol, acetone, methyl isobutyl ketone, Ketone solvents such as methyl ethyl ketone pentanone, hexanone, cyclohexanone, isophorone, acetophenone, cellsolves such as methyl cellosolve, ethyl cellosolve, methyl acetate, ethyl acetate, acetic acid Ester solvents such as chill, methyl propionate, butyl formate, ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso- Glycol ether solvents such as butyl ether, triethylene glycol mono-n-butyl ether, and tetraethylene glycol mono-n-butyl ether can be used, and one or more of these can be used in combination.

The organic solvent (C) is preferably 80 parts by mass or more, more preferably 90 parts by mass or more, and further preferably 100 parts by mass or more with respect to 100 parts by mass of the acid-modified polyolefin (A). Preferably, it is 110 parts by mass or more. Further, it is preferably 1000 parts by mass or less, more preferably 900 parts by mass or less, still more preferably 800 parts by mass or less, and particularly preferably 700 parts by mass or less. If it is less than the said range, liquid state and pot life property may fall, and when it exceeds the said range, it may become disadvantageous from the surface of manufacturing cost and transport cost.

The organic solvent (C) is one selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons and halogenated hydrocarbons from the viewpoint of the liquidity and pot life properties of the adhesive composition. A mixed liquid of at least one solvent (C2) selected from the group consisting of the above solvent (C1), alcohol solvent, ketone solvent, ester solvent and glycol ether solvent is preferable. The mixing ratio is preferably solvent (C1) / solvent (C2) = 50 to 97/50 to 3 (mass ratio), more preferably 55 to 95/45 to 5 (mass ratio), The ratio is more preferably 60 to 90/40 to 10 (mass ratio), and particularly preferably 70 to 80/30 to 20 (mass ratio). If it is out of the above range, the liquid state and pot life of the adhesive composition may be lowered. Moreover, it is especially preferable that the solvent (C1) is an aromatic hydrocarbon or an alicyclic hydrocarbon, and the solvent (C2) is a ketone solvent.

<Adhesive composition>
The adhesive composition according to the present invention is a mixture of the acid-modified polyolefin (A), the glycidylamine type epoxy resin (B1), the glycidyl ether type epoxy resin (B2) and the organic solvent (C). The acid-modified polyolefin (A), glycidylamine type epoxy resin (B1) and glycidyl ether type epoxy resin (B2) may be dissolved or dispersed in the organic solvent (C). It is preferably dissolved from the viewpoint of pot life.

In addition to the acid-modified polyolefin (A), glycidylamine-type epoxy resin (B1), glycidyl ether-type epoxy resin (B2), and organic solvent (C), the adhesive composition can be used in various ways as long as the performance of the present invention is not impaired. These additives can be blended and used. Although it does not specifically limit as an additive, It is preferable to use a flame retardant, a pigment, an antiblocking agent, etc.

<< Sealant layer >>
The sealant layer used in the present invention is not particularly limited, but it is preferable to use polyolefin from the viewpoints of leakage resistance and heat resistance. The polyolefin may be appropriately selected from conventionally known polyolefin resins. For example, although not particularly limited, polyethylene, polypropylene, ethylene-propylene copolymer, and the like can be used. Among these, polypropylene is preferably used, and polypropylene may be appropriately selected from random propylene, homopropylene, and block propylene.

The sealant layer in the present invention may be multilayered by combining the above-mentioned types of polypropylene layers as appropriate. The thickness is not particularly limited, but is preferably 20 to 100 μm, more preferably 25 to 95 μm, and even more preferably 30 to 90 μm. In addition, you may mix | blend a pigment and various additives with a polyolefin resin base material as needed.

<< Barrier layer >>
The barrier layer used in the present invention is a layer having a barrier property that prevents entry of oxygen, moisture, or the like into the lithium ion battery. Although not particularly limited, metal foils such as pure aluminum, aluminum-iron alloy, copper, nickel, and stainless steel, and vapor deposition films such as aluminum, nickel, silica, and alumina are preferable. It is preferable to use an aluminum foil from the viewpoint of barrier properties. In order to improve corrosion resistance and adhesion, the barrier layer is preferably subjected to a surface treatment such as chromate treatment. Specifically, chromate chromate treatment, phosphoric acid chromate treatment, and coating type chromate treatment. Or a non-chromium (coating type) chemical conversion treatment using zirconium, titanium, zinc phosphate or the like. These treatments may be carried out alone or appropriately in combination with an organic binder component.

When aluminum foil is used, a soft aluminum foil with a thickness of 9 to 200 μm, particularly a soft aluminum foil with an iron content of 0.1 to 9.0% by mass, is resistant to pinholes and is easy to stretch during molding. Is preferable. When the iron content is less than 0.1% by mass, sufficient pinhole resistance and spreadability cannot be imparted, and when it exceeds 9.0% by mass, flexibility may be impaired.

When using a soft aluminum foil, it is preferable to perform a known surface treatment on the surface on which the adhesive layer is laminated in order to improve the adhesion to the adhesive layer in addition to the improvement in corrosion resistance.

<< Battery packaging materials >>
As described above, the battery packaging material of the present invention is formed by laminating a barrier layer, an adhesive layer, and a sealant layer in this order.

Next, an example of the method for producing the battery packaging material of the present invention will be described.

In the present invention, an adhesive layer is first provided on the surface of the barrier layer. In the present invention, the method for providing the adhesive layer is not particularly limited, but includes the acid-modified polypropylene resin (A), the glycidylamine type epoxy resin (B1), the glycidyl ether type epoxy resin (B2), and the organic solvent (C). The adhesive composition to be applied is applied to the surface of the barrier layer, the organic solvent (C) is removed by drying, and then a curing reaction is performed. Further, there may be mentioned a method in which an adhesive composition is applied on release paper, the organic solvent (C) is dried and subjected to a curing reaction to once peel the adhesive layer, and then transferred to the barrier layer or sealant layer. Among these, from the viewpoint of performance, the former method is preferable from the viewpoint of easily controlling the thickness of the adhesive layer, and among them, the method of applying the adhesive composition to the surface of the barrier layer is preferable in practice.

As an application method of the adhesive composition, known methods such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, brush coating method, etc. Uniformly coat the surface of the barrier layer or sealant layer, set it at room temperature as necessary, and then subject it to a drying treatment or a heat treatment for drying to form a uniform adhesive layer in close contact with the coated surface can do.

) After providing the adhesive layer, provide the sealant layer. The method of providing the sealant layer is not particularly limited, but a method of bonding the sealant film made of the above-described sealant resin and the adhesive layer by heat (thermal lamination, dry lamination), or extruding and pasting the resin melted in the adhesive layer. A method of matching (extrusion lamination) and the like can be mentioned.

The battery packaging material of the present invention can be produced by the above method, and according to such a method, the thickness of the adhesive layer can be easily adjusted, so that the packaging material can be produced efficiently.

The battery packaging material of the present invention has a structure in which a barrier layer, an adhesive layer, and a sealant layer are laminated in this order in the thickness direction, and a base layer made of a single-layer or multilayer heat-resistant polymer film is further provided. May be.

The base layer may be, for example, a single film such as a stretched or unstretched film such as a polyester film, a polyamide film, or a polypropylene film, or a multilayer film in which the single films are laminated.

A primer layer can be provided between the base material layer and the barrier layer as necessary. For the primer layer, a polyurethane adhesive mainly composed of a silane coupling agent, polyester polyol, polyether polyol, or acrylic polyol can be used.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples. In the examples and comparative examples, “parts” simply means “parts by mass”.

Production Example 1
In a 1 L autoclave, 100 parts by mass of a propylene-butene copolymer (“Tafmer (registered trademark) XM7080” manufactured by Mitsui Chemicals), 150 parts by mass of toluene and 25 parts by mass of maleic anhydride, 6 parts by mass of di-tert-butyl peroxide Was added, and the temperature was raised to 140 ° C., followed by further stirring for 3 hours. Then, after cooling the obtained reaction liquid, it poured into the container containing a lot of methyl ethyl ketone, and resin was deposited. Thereafter, the liquid containing the resin was centrifuged to separate and purify an acid-modified propylene-butene copolymer grafted with maleic anhydride, (poly) maleic anhydride and a low molecular weight product. Thereafter, by drying at 70 ° C. under reduced pressure for 5 hours, a maleic anhydride-modified propylene-butene copolymer (PO-1, acid value 48 mgKOH / g-resin, weight average molecular weight 50,000, Tm 75 ° C., ΔH25J / g) was obtained.

Production Example 2
A maleic anhydride-modified propylene-butene copolymer (PO-2, acid value 25 mgKOH / g-resin, weight average) was obtained in the same manner as in Production Example 1 except that the amount of maleic anhydride charged was changed to 20 parts by mass. Molecular weight 80,000, Tm 75 ° C., ΔH 30 J / g) was obtained.

Production Example 3
A maleic anhydride-modified propylene-butene copolymer (with the same procedure as in Production Example 1 except that the amount of maleic anhydride charged was changed to 3 parts by mass and the amount of di-tert-butyl peroxide was changed to 0.5 parts by mass ( PO-3, acid value 5 mg KOH / g-resin, weight average molecular weight 180,000, Tm 80 ° C., ΔH 25 J / g).

Production Example 4
A maleic anhydride-modified propylene-butene copolymer (PO-4, acid value 55 mgKOH / g-resin, weight average) was obtained in the same manner as in Production Example 1 except that the amount of maleic anhydride charged was changed to 30 parts by mass. Molecular weight 40,000, Tm 70 ° C., ΔH 25 J / g) was obtained.

Production Example 5
A maleic anhydride-modified propylene-butene copolymer was prepared in the same manner as in Production Example 1 except that the amount of maleic anhydride charged was changed to 2 parts by mass and the amount of di-tert-butyl peroxide was changed to 0.5 parts by mass. PO-5, acid value 3 mg KOH / g-resin, weight average molecular weight 200,000, Tm 80 ° C., ΔH 25 J / g).

(Preparation of main agent 1)
In a 500 ml four-necked flask equipped with a water-cooled reflux condenser and a stirrer, 100 parts by mass of maleic anhydride-modified propylene-butene copolymer (PO-1) obtained in Production Example 1 and 280 parts by mass of methylcyclohexane 120 parts by mass and methyl ethyl ketone were charged, the temperature was raised to 80 ° C. while stirring, and stirring was continued for 1 hour to obtain main agent 1. The solution state is shown in Table 1.

(Preparation of main ingredients 2-12)
The acid-modified polyolefin and the organic solvent were changed as shown in Table 1, and main agents 2 to 12 were produced in the same manner as main agent 1. Table 1 shows the blending amount and the solution state.

Example 1
500 parts by mass of main agent 1, 19.8 parts by mass of phenol novolac type epoxy resin as glycidyl ether type epoxy resin (B2) as curing agent, and TETRAD (registered trademark) -X as glycidylamine type epoxy resin (B1) 0.2 mass part was mix | blended and the adhesive composition was obtained. Table 2 shows the evaluation results of pot life, adhesiveness and chemical resistance.

Examples 2 to 15 and Comparative Examples 1 to 6
The main agents 1 to 12 and the respective curing agents were changed as shown in Tables 2 and 3, and Examples 2 to 15 and Comparative Examples 1 to 6 were performed in the same manner as in Example 1. Tables 2 and 3 show the blending amount, pot life property, adhesiveness and chemical resistance.

The curing agents used in Tables 2 and 3 are as follows.
<Glycidylamine type epoxy resin (B1)>
N, N, N ′, N′-tetraglycidyl-m-xylenediamine: TETRAD (registered trademark) -X (manufactured by Mitsubishi Gas Chemical Company)
<Glycidyl ether type epoxy resin (B2)>
Phenol novolac type epoxy resin: jER (registered trademark) 152 (manufactured by Mitsubishi Chemical Corporation)
o-Cresol novolac type epoxy resin: YDCN-700-3 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.)
<Other curing agents>
Polyisocyanate: Duranate (registered trademark) TPA-100 (manufactured by Asahi Kasei Corporation)
Silane coupling agent: KBM-403 (manufactured by Shin-Etsu Silicone)

Analytical measurement and evaluation were performed on each acid-modified polyolefin, main agent, and adhesive composition obtained as described above based on the following methods.

Measurement of Acid Value The acid value (mgKOH / g-resin) in the present invention was prepared with a chloroform solution of maleic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) using FT-IR (manufactured by Shimadzu Corporation, FT-IR8200PC). Using the coefficient (f) obtained from the calibration curve and the absorbance (I) of the stretching peak (1780 cm ⁻¹ ) of the carbonyl (C═O) bond of maleic anhydride in the crystalline maleic anhydride-modified polyolefin solution, the following formula is used. It is the value.
Acid value (mgKOH / g-resin) = [absorbance (I) × (f) × 2 × molecular weight of potassium hydroxide × 1000 (mg) / molecular weight of maleic anhydride]
Molecular weight of maleic anhydride: 98.06 Molecular weight of potassium hydroxide: 56.11

Measurement of weight average molecular weight (Mw) The weight average molecular weight in the present invention is a gel permeation chromatograph Alliance e2695 (hereinafter referred to as GPC, standard substance: polystyrene resin, mobile phase: tetrahydrofuran, column: Shodex KF-806 + KF manufactured by Nippon Waters Co., Ltd.). -803, column temperature: 40 ° C., flow rate: 1.0 ml / min, detector: photodiode array detector (wavelength 254 nm = ultraviolet)).

Measurement of melting point and heat of fusion The melting point and heat of fusion in the present invention are increased at a rate of 20 ° C./minute using a differential scanning calorimeter (hereinafter DSC, manufactured by TA Instruments Japan, Q-2000). It is a value measured from the top temperature and area of the melting peak when heated and melted into a cooled resin and then heated and melted again.

Evaluation of the main agent solution state The solution states of the main agents 1 to 12 were evaluated by measuring the solution viscosity at 25 ° C. using a Brookfield viscometer TVB-10M (hereinafter referred to as B type viscometer) manufactured by Toki Sangyo Co., Ltd. did.
<Evaluation criteria>
○ (Excellent in practical use): Less than 500 mPa · s Δ (Practical use): 500 mPa · s or more and less than 1000 mPa · s × (Unusable): 1000 mPa · s or more or viscosity measurement is impossible due to gelation

Evaluation of pot life property Pot life property refers to the stability of the solution immediately after the compounding or after a certain time has elapsed after the compounding with the acid-modified polyolefin. If the pot life is good, it means that the viscosity of the solution is small and can be stored for a long time. If the pot life is poor, the viscosity of the solution increases (thickens). It means that gelation occurs, application to a substrate becomes difficult, and long-term storage is impossible. The pot life properties of the adhesive compositions obtained in Examples 1 to 15 and Comparative Examples 1 to 6 were stored at 25 ° C. and 40 ° C. for 24 hours, and then the solution viscosity at 25 ° C. using a B-type viscometer. It was evaluated by measuring.
<Evaluation criteria>
○ (Excellent in practical use): Less than 500 mPa · s Δ (Practical use): 500 mPa · s or more and less than 1000 mPa · s × (Unusable): 1000 mPa · s or more or viscosity measurement is impossible due to gelation

Preparation of packaging material for lithium ion battery Aluminum foil (UACJ, 8079-0 material, thickness 40 μm) is used for the barrier layer, and unstretched polypropylene film (Toyobo Pyrene (registered trademark) film CT, thickness is used for the sealant) 40 μm) (hereinafter also referred to as CPP). The adhesive compositions obtained in Examples 1 to 15 and Comparative Examples 1 to 6 were applied on the surface of the barrier layer using a bar coater so that the thickness of the adhesive layer after drying was adjusted to 3 μm. Subsequently, it was dried for 1 minute in a 100 ° C. atmosphere using a warm air dryer to obtain a 3 μm thick adhesive layer. A sealant layer is overlaid on the surface of the adhesive layer, and bonded at 80 ° C., 0.3 MPa, 1 m / min using a small desktop test laminator (SA-1010-S) manufactured by Tester Sangyo Co., Ltd., 40 ° C., 50% The lithium ion battery packaging material was obtained by aging for 120 hours with RH.

The lithium ion battery packaging material obtained as described above was evaluated by the following method.

Evaluation of Adhesiveness The battery packaging material was cut into a size of 100 mm × 15 mm, and the adhesiveness was evaluated by a T-type peel test. The evaluation results are shown in Tables 2 and 3.

<T-type peel test>
Based on the test method of ASTM-D1876-61, the peel strength at a tensile speed of 50 mm / min was measured in a 25 ° C environment using Tensilon RTM-100 manufactured by Orientec Corporation. The peel strength (N / cm) between the barrier layer (aluminum foil) / sealant layer (CPP) was the average of five test values.

<Evaluation criteria>
☆ (Particularly excellent in practical use): 8.0 N / cm or more or CPP breaks material (hereinafter also simply referred to as “material breakage”). Material breakage is aluminum that does not peel at the aluminum foil / CPP interface. Foil or CPP is destroyed.
◎ (Excellent in practical use): 7.5 N / cm or more and less than 8.0 N / cm ○ (Practical use): 7.0 N / cm or more and less than 7.5 N / cm × (Not practical): Less than 7.0 N / cm

Evaluation of Electrolytic Solution Resistance The battery packaging material was cut into a size of 100 mm × 15 mm, and the electrolyte [ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (volume ratio) lithium hexafluorophosphate Were added at 85 ° C. for 3 days. Thereafter, the laminate was taken out, washed with ion-exchanged water, wiped off with water with a paper wiper, and evaluated for electrolyte resistance by a T-type peel test.

<Evaluation criteria>
☆ (Particularly excellent in practical use): 8.0 N / cm or more or material breakage ◎ (Excellent in practical use): 7.5 N / cm or more and less than 8.0 N / cm ○ (Practical use): 7.0 N / cm or more Less than 5 N / cm x (impractical): less than 7.0 N / cm

The battery packaging material of the present invention uses a composition comprising a specific resin and a specific cross-linking agent in the battery packaging material in which a barrier layer, an adhesive layer, and a sealant layer are sequentially laminated. For this reason, it exhibits excellent electrolyte resistance when used as a battery packaging material. As a result, the life of the battery is extended and the safety in handling is increased, and lithium used in personal computers, mobile phones, video cameras, etc. It can be widely used as a battery packaging material (pouch form).

Claims

A battery packaging material in which a barrier layer, an adhesive layer and a sealant layer are laminated in this order, wherein the adhesive layer is an acid-modified polyolefin (A) having an acid value of 5 to 50 mgKOH / g-resin, a glycidylamine type A battery packaging material comprising a reaction product of an epoxy resin (B1) and a glycidyl ether type epoxy resin (B2).
The battery packaging material according to claim 1, wherein the glycidylamine type epoxy resin (B1) is an epoxy resin having two or more glycidyl groups in one molecule.
The battery packaging material according to claim 1 or 2, wherein the glycidylamine type epoxy resin (B1) is a compound represented by the general formula (1).

(In the general formula (1), R is an aryl group which may have a substituent, and A1 and A2 are each independently an alkylene group having 1 to 5 carbon atoms which may have a substituent, m is 1 or 2, and n is 1 or 2.)
The battery packaging material according to any one of claims 1 to 3, wherein the glycidyl ether type epoxy resin (B2) is an epoxy resin having two or more glycidyl groups in one molecule and containing no nitrogen atom. .
The adhesive layer comprises 0.01 to 20 parts by mass of glycidylamine type epoxy resin (B1) and 1 to 20 parts by mass of glycidyl ether type epoxy resin (B2) with respect to 100 parts by mass of acid-modified polyolefin (A). The battery packaging material according to any one of claims 1 to 4, comprising a reactant.
A battery using the battery packaging material according to any one of claims 1 to 5.
An adhesive composition containing acid-modified polyolefin (A), glycidylamine type epoxy resin (B1), glycidyl ether type epoxy resin (B2) and organic solvent (C) is applied to the surface of the barrier layer, dried and bonded. 6. The method for producing a battery packaging material according to claim 1, wherein a layer is formed, and then a sealant layer is laminated on the surface of the adhesive layer.
The organic solvent (C) is a mixed liquid of a solvent (C1) and a solvent (C2), and the solvent (C1) is composed of an aromatic hydrocarbon, an aliphatic hydrocarbon, an alicyclic hydrocarbon, and a halogenated hydrocarbon. One or more solvents selected from the group consisting of one or more solvents selected from the group consisting of alcohol solvents, ketone solvents, ester solvents and glycol ether solvents. The method for producing a battery packaging material according to claim 7, wherein solvent (C1) / solvent (C2) = 50 to 97/50 to 3 (mass ratio).