JP6435092B2 - Modified polyolefin resin - Google Patents

Description

  The present invention provides a modified polyolefin for battery exterior material adhesive that has excellent adhesion between a metal foil and a resin film constituting a lithium ion battery exterior, has durability against an electrolyte, and is excellent in low-temperature storage stability of a solution. A resin is provided.

  A typical lithium ion secondary battery includes a positive electrode, a negative electrode, a non-aqueous electrolyte, and a separator. The outer packaging material that wraps these products has been made of pressed steel plates and metal cans made of aluminum plates. In recent years, however, the use of aluminum laminate films that can reduce battery weight and provide a high degree of freedom in shape has expanded. Yes.

  Batteries with aluminum laminate film as exterior materials are portable electronic devices such as mobile phones, high-performance mobile phones (smartphones), notebook computers, tablet computers, digital cameras, e-books, electric vehicles, and hybrids. Widely used in electric vehicles such as electric cars.

  This aluminum laminate film generally has a laminated structure comprising an outer layer made of heat-resistant polyester resin or polyamide resin, an intermediate layer made of aluminum foil or the like (barrier layer) and an inner layer made of polyolefin resin or the like. The inner layer is required to have heat sealability in order to heat-bond the inner layers to each other and seal the battery in a pouch shape.

  For adhesion between the outer layer and the intermediate layer, a general adhesive such as a polyester-based adhesive, a polyurethane-based adhesive, or an acrylic adhesive is used. On the other hand, it is known that an acid-modified polypropylene adhesive is used for adhesion between the intermediate layer and the inner layer (Patent Documents 1 and 2).

  In some cases, an acid-modified polyolefin resin is used as an inner layer and directly laminated on the barrier layer.

JP 2011-256339 A JP 2010-086744 A

  However, the acid-modified polypropylene adhesives disclosed in Patent Documents 1 and 2 (random polypropylene containing a comonomer during polymerization) have a melting point or softening point in the range of 110 ° C to 165 ° C. When acid-modified polypropylene is laminated and used as an adhesive between the intermediate layer and the inner layer, it is necessary to heat and dissolve it above the melting point of the polyolefin resin used for the inner layer. When the acid-modified polypropylene adhesives of Patent Documents 1 and 2 are used, there arises a problem that the shape of the inner layer (polyolefin resin) substrate is deformed by heating.

  In addition, since conventional acid-modified polypropylene adhesives have poor solvent solubility, they are difficult to apply and use, and have problems such as poor solution stability (especially stability at low temperatures). Yes.

  On the other hand, when an acid-modified polypropylene adhesive having a melting point of 110 ° C. or higher is used instead of an acid-modified polypropylene adhesive having a melting point of 110 ° C. or higher, the inner layer base material is deformed, the solvent is soluble, and the solution is stable. However, new problems such as a decrease in resistance to electrolytic solution occur.

  Therefore, the present invention is a modified polyolefin-based lithium ion battery exterior material adhesive that has excellent adhesion to each layer constituting the lithium ion battery exterior material, has durability against an electrolytic solution, and is excellent in solution stability. The object is to provide a resin.

The present invention provides the following [1] to [4].
[1] Modified polyolefin system in which component (A): polyolefin resin is graft-modified with component (B): α, β-unsaturated carboxylic acid or derivative thereof, and component (C): (meth) acrylic acid ester Containing resin,
The modified polyolefin resin has a melting point of 70 ° C. to 90 ° C. by a differential scanning calorimeter (DSC) and a weight average molecular weight of 100,000 to 200,000.
Modified polyolefin resin with solvent resistance.
[2] The modified polyolefin resin according to the above [1], wherein the component (C) contains at least a compound represented by the general formula (I).
CH ₂ = CR ₁ COOR ₂ (I)
(In the formula (I), R ₁ = H or _{CH 3, R 2 = C n} H 2n + 1, n = 8~18 integer)
[3] The above [1], wherein the component (A) contains at least one selected from the group consisting of an ethylene-propylene copolymer, a propylene-1-butene copolymer, and an ethylene-propylene-1-butene copolymer. Or the modified polyolefin resin as described in [2].
[4] Any one of [1] to [3] above, wherein at least one of the graft weight of component (B) and the graft weight of component (C) in the modified polyolefin resin is 0.1 to 10% by weight. The modified polyolefin resin according to one item.

  According to the present invention, it is possible to provide a modified polyolefin resin having excellent adhesiveness, durability against an electrolytic solution, and excellent solution stability.

FIG. 1 is a diagram schematically showing a cross-sectional view of a first example of a lithium ion battery exterior material of the present invention. FIG. 2 is a diagram schematically showing a cross-sectional view of a second example of the lithium ion battery exterior material of the present invention.

  In the modified polyolefin resin of the present invention, component (A): polyolefin resin is graft-modified with component (B): α, β-unsaturated carboxylic acid or a derivative thereof, and component (C): (meth) acrylic ester. It contains modified polyolefin resin. The melting point of the modified polyolefin resin by differential scanning calorimeter (DSC) is 70 ° C. to 90 ° C., and the weight average molecular weight is 100,000 to 200,000.

  The reason why the modified polyolefin resin of the present invention exhibits an excellent effect is presumed as follows. In general, if the weight average molecular weight of the modified polyolefin resin is small, sufficient durability (solvent resistance) against a solvent such as an electrolytic solution is difficult to obtain, whereas if the weight average molecular weight is large, good adhesion is obtained. It becomes difficult to obtain. In addition, when the molecular weight distribution of the modified polyolefin resin is wide, both the influence when the weight average molecular weight is small and the influence when the weight average molecular weight are large may occur. Furthermore, when the melting point of the modified polyolefin resin is low, it is difficult to obtain sufficient durability (solvent resistance) against a solvent such as an electrolytic solution. On the other hand, when the melting point is high, the shape of the base material is not deformed. There is a tendency that adhesion at a relatively low temperature, good solvent solubility, and solution stability at a low temperature are difficult to obtain.

  On the other hand, the modified polyolefin resin of the present invention contains a graft component derived from components (B) and (C), and has a melting point and a weight average molecular weight within a predetermined range, and thus exhibits an excellent effect. It is thought that.

  The modified polyolefin resin of the present invention can be obtained by graft polymerization of the component (B) and the component (C) to the component (A). The method for synthesizing the modified polyolefin resin can be carried out by a known method, and component (D): radical generator may be used in the production. For example, a solution method in which a mixture of components (A), (B) and (C) is dissolved in an organic solvent such as toluene by heating and a component (D): radical generator is added, or a Banbury mixer, kneader, extrusion Examples include a method of adding a component (A), (B), (C) and (D) using a kneader such as a machine and obtaining a modified polyolefin resin by a melt kneading reaction under heating. Components (A), (B), (C) and (D) may be added all at once or sequentially.

  In the present invention, the weight average molecular weight of the modified polyolefin resin is 100,000 to 200,000, preferably 110,000 to 190,000, more preferably 120,000 to 180,000. When the weight average molecular weight is 100,000 or more, sufficient durability against the electrolytic solution of the battery can be obtained. By being 200,000 or less, sufficient solvent solubility can be obtained when the adhesive is used. The weight average molecular weight in the present invention including the examples is a value calculated by measuring with gel permeation chromatography (standard substance: polystyrene).

  In this invention, melting | fusing point (henceforth, Tm) by a differential scanning calorimeter (henceforth, DSC) of modified polyolefin resin is 70 to 90 degreeC, It is preferable that it is 71 to 89 degreeC, More preferably 73 to 87 ° C. When the melting point is 70 ° C. or higher, sufficient adhesive strength can be obtained. On the other hand, when the melting point is 90 ° C. or lower, the adhesiveness at a relatively low temperature that does not cause deformation of the shape of the base material is good, the solution stability is good, and sufficient storage stability at a low temperature is achieved. Can be obtained.

  The measurement of Tm by DSC in the present invention can be performed, for example, under the following conditions. In accordance with JIS K7121-1987, using a DSC measuring apparatus (manufactured by Seiko Denshi Kogyo), about 5 mg of sample is kept in a heated and melted state at 150 ° C. for 10 minutes, and then cooled at a rate of 10 ° C./min to −50 ° Then, the melting peak temperature at the time of melting at 150 ° C. at 10 ° C./min is measured, and the temperature is evaluated as Tm. In the examples described later, Tm is measured under the conditions described above.

  The polyolefin resin as the component (A) is not particularly limited, but a homopolymer of ethylene or propylene, ethylene or propylene and another comonomer (for example, butene-1, pentene-1, hexene-1, butene-1, heptene- Examples thereof include comonomers having 2 or more carbon atoms, such as 1, octene-1, etc. Preferably, random copolymers or block copolymers of 2 to 6 α-olefin comonomers, copolymers obtained by polymerizing two or more types of comonomers, and the like. And ethylene-propylene copolymer, propylene-1-butene copolymer, and ethylene-propylene-1-butene copolymer are more preferable.

  Component (B) is an α, β-unsaturated carboxylic acid or derivative thereof. α, β-unsaturated carboxylic acid and its derivatives include maleic acid, maleic anhydride, fumaric acid, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, hymic anhydride Examples include acid, (meth) acrylic acid, (meth) acrylic acid ester, etc., and maleic anhydride is preferred. Component (B) may be one or more compounds selected from α, β-unsaturated carboxylic acids and derivatives thereof, a combination of one or more α, β-unsaturated carboxylic acids and one or more derivatives thereof, A combination of two or more α, β-unsaturated carboxylic acids or a combination of two or more derivatives of α, β-unsaturated carboxylic acids may be used.

  The graft weight of the component (B) in the modified polyolefin resin is preferably 0.1 to 10% by weight, more preferably 0.5 to 4% by weight when the modified polyolefin resin is 100% by weight. is there. When the graft weight is 0.1% by weight or more, the adhesion of the resulting modified polyolefin resin to a material such as a metal adherend can be maintained. When the graft weight is 10% by weight or less, generation of unreacted grafts can be prevented, and sufficient adhesion to the resin adherend can be obtained.

  The graft weight% of component (B) can be measured by a known method. For example, it can be determined by alkali titration or Fourier transform infrared spectroscopy.

  Component (C) is a (meth) acrylic acid ester. (Meth) acrylic acid ester is an ester of acrylic acid or methacrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, hydroxyethyl (meth) acrylate, Isobornyl (meth) acrylate, glycidyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenyl ( (Meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N, N-dimethylamino Ethyl (meth) acrylate, acetoacetoxyethyl (meth) acrylate.

The component (C) preferably contains a (meth) acrylic acid ester represented by the general formula (I), and more preferably a (meth) acrylic acid ester represented by the general formula (I).
CH ₂ = CR ₁ COOR ₂ (I)

  This suppresses molecular weight reduction from the polyolefin resin (A) when synthesizing the modified polyolefin resin, and narrows the molecular weight distribution. Solvent solubility of the modified polyolefin resin, low temperature stability of the solution, adhesion Compatibility with other resins in the agent composition and adhesion can be improved. The (meth) acrylic acid ester represented by the general formula (I) can be used alone or in a mixture of plural kinds at an arbitrary ratio.

In the general formula (I), R ₁ represents H or CH ₃ and is preferably CH ₃ . R ₂ represents C _n H _{2n + 1} . n represents an integer of 8 to 18, and n is preferably 8 to 15, more preferably 8 to 14, and still more preferably 8 to 13. As the compound represented by the formula (I), lauryl (meth) acrylate and octyl (meth) acrylate are preferable, and lauryl methacrylate and octyl methacrylate are more preferable.

  The graft weight of the component (C) in the modified polyolefin resin is preferably 0.1 to 10% by weight, more preferably 0.5 to 4% by weight, when the modified polyolefin resin is 100% by weight. is there. When the graft weight is 0.1% by weight or more, the molecular weight distribution of the modified polyolefin resin can be kept in a sufficiently narrow range. That is, the adverse effect of the high molecular weight portion can be prevented, and the solvent solubility, the low temperature stability of the solution, and the compatibility with other resins can be maintained well. Moreover, the bad influence of a low molecular weight part can be prevented and adhesive force can be improved. When the graft weight is 10% by weight or less, the generation of unreacted grafts can be prevented, and the adhesion to the resin adherend can be maintained well.

The graft weight% of component (C) can be measured by a known method. For example, it can be determined by Fourier transform infrared spectroscopy or ¹ H-NMR.

  It is preferable that either the graft weight of the component (B) and the graft weight of the component (C) in the modified polyolefin-based resin is 0.1 to 10% by weight, and both are 0.1 to 10% by weight. More preferably.

  In the present invention, graft components other than the components (B) and (C) can be used in combination within the range not impairing the characteristics of the present invention, depending on the application and purpose. Examples of graft components that can be used include (meth) acrylic acid, (meth) acrylic acid derivatives other than component (C) (for example, N-methyl (meth) acrylamide, hydroxyethyl (meth) acrylamide, (meth) acryloyl). Morpholine and the like). The graft components other than the components (B) and (C) in the modified polyolefin resin may be used alone or in combination of a plurality of types, and the total graft weight is the component (B), It is preferable not to exceed the total graft weight of (C).

  The radical generator as the component (D) can be appropriately selected from known radical generators, and organic peroxide compounds are preferred. Examples of organic peroxide compounds include di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, benzoyl peroxide, dilauryl peroxide, cumene hydroperoxide, and t-butyl hydroperoxide. 1,4-bis [(t-butylperoxy) isopropyl] benzene, 1,1-bis (t-butylperoxy) -3,5,5-trimethylcyclohexane, 1,1-bis (t-butylper) Oxy) -cyclohexane, cyclohexanone peroxide, t-butylperoxybenzoate, t-butylperoxyisobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxy-2- Ethyl hexanoate, t-butyl peroxyisop Pills carbonate, include cumylperoxy octoate, etc., di -t- butyl peroxide, dicumyl peroxide and dilauryl peroxide are preferred. Component (D) may be a single radical generator or a combination of a plurality of radical generators.

  The addition amount of the component (D) in the graft polymerization reaction is preferably 1 to 100% by weight, more preferably, based on the total amount (weight) of the addition amount of the component (B) and the addition amount of the component (C). 10 to 50% by weight. By being 1% by weight or more, sufficient graft efficiency can be maintained. By being 100 weight% or less, the fall of the weight average molecular weight of modified polyolefin resin can be prevented.

  The modified polyolefin resin of the present invention may be used as a composition in combination with a curing agent. Examples of the curing agent include a polyisocyanate compound, an epoxy compound, a polyamine compound, a polyol compound, or a crosslinking agent whose functional group is blocked with a protective group. A hardening | curing agent may be individual and may be a combination of multiple types. The blending amount of the curing agent can be appropriately selected depending on the content of the α, β-unsaturated carboxylic acid or derivative thereof in the modified polyolefin resin of the present invention. Moreover, when mix | blending a hardening | curing agent, according to the objective, catalysts, such as an organotin compound and a tertiary amine compound, can be used together. The adhesive of the present invention may be blended with known adhesives such as polyester adhesives, polyurethane adhesives, acrylic adhesives and the like as long as the desired effects are not impaired.

  In the present invention, the solvent resistance means that performance (for example, adhesiveness) is not lost even in contact with other solvents. Since the modified polyolefin resin of the present invention has the above structure, it has solvent resistance in a wide temperature range (for example, −30 ° C. to 90 ° C.) including normal temperature. Therefore, when used as an adhesive for battery exterior materials, temperature changes in the battery storage or use environment, especially chemical temperature rise of battery constituent materials accompanying charging or discharging, temperatures higher than room temperature in summer, automobiles, etc. Adhesiveness etc. can be maintained in the range.

  The modified polyolefin resin of the present invention has solvent resistance. The solvent is preferably a solvent used in the electrolytic solution, and more preferably an organic solvent used in the electrolytic solution. Examples of the organic solvent used in the electrolytic solution include carbonate solvents such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. The electrolytic solution may contain an inorganic solid electrolyte such as lithium hexafluorophosphate in addition to the solvent. The electrolytic solution may be one type of solvent or a mixed solution of two or more types of solvents.

  The modified polyolefin-based resin of the present invention can exhibit stability as a solution, particularly stability at low temperatures, by having the above structure. Moreover, the modified polyolefin resin of the present invention can exhibit excellent adhesion to both metals and resins, and the adhesion can be exhibited even at high temperatures. These points are also useful as an adhesive for battery exterior materials.

  The modified polyolefin resin of the present invention is excellent in metal foil and film (polyolefin resin film, etc.), metal foils, adhesion between films (particularly adhesion at low temperatures), solution stability and durability against electrolytes, It is useful as an adhesive in laminated films such as aluminum laminated films. The laminate film can be used as a battery exterior material for a lithium ion secondary battery. Moreover, it has the same electrochemical cell structure as a lithium ion secondary battery, and can be used as exterior materials, such as a capacitor | condenser and an electric double layer capacitor, for which equivalent performance is required.

  As a first example of the lithium ion battery exterior material of the present invention, an outer layer, an intermediate layer and an inner layer are provided in this order, and an adhesive containing the modified polyolefin resin of the present invention is included between the intermediate layer and the inner layer. The aspect which has a laminated body which has an contact bonding layer is mentioned. FIG. 1 is a diagram schematically showing a cross-sectional view of a first example of a lithium ion battery exterior material of the present invention. In the lithium ion battery exterior material 100 of FIG. 1, an outer layer 11, an adhesive layer 12, an intermediate layer (barrier layer) 13, an adhesive layer 14 and an inner layer 15 are sequentially laminated.

  As a second example of the lithium ion battery exterior material of the present invention, the outer layer, the intermediate layer, and the inner layer are provided in this order, the inner layer includes the adhesive of the present invention, and the inner layer is laminated on the intermediate layer. An embodiment is mentioned. FIG. 2 is a diagram schematically showing a cross-sectional view of a second example of the lithium ion battery exterior material of the present invention. In the lithium ion battery exterior material 200 of FIG. 2, an outer layer 21, an adhesive layer 22, an intermediate layer (barrier layer) 23, and an inner layer 24 are sequentially laminated.

  The outer layer 11 is preferably composed of an insulating resin, and examples thereof include polyester and polyamide. The outer layer 11 may be a single layer or may be composed of two or more layers.

  The adhesive layer 12 is a layer that adheres the outer layer 11 and the intermediate layer 13. The adhesive contained in the adhesive layer 12 is not particularly limited, and examples thereof include an adhesive containing the modified polyolefin resin of the present invention, a polyester adhesive, a polyurethane adhesive, and an acrylic adhesive.

  The intermediate layer (barrier layer) 13 is preferably made of a metal foil. As metal foil, metal foil containing metals, such as aluminum, aluminum alloy, nickel, stainless steel, is illustrated, and metal foil containing aluminum and aluminum alloy is preferable. The intermediate layer 13 may be a single layer or may be composed of two or more layers.

  The adhesive layer 14 is a layer that adheres the intermediate layer 13 and the inner layer 15 and includes an adhesive containing the modified polyolefin resin of the present invention.

  The inner layer 15 is preferably a resin having heat weldability. Examples of such resins include polyolefin resins. The inner layer 15 may be a single layer or may be composed of two or more layers.

  The definitions and examples of the outer layer 21, the adhesive layer 22, and the intermediate layer 23 are the same as the definitions and examples of the outer layer 11, the adhesive layer 12, and the intermediate layer 13, respectively. The inner layer 24 includes an adhesive containing the modified polyolefin resin of the present invention, and is directly laminated on the intermediate layer 23. The inner layer 24 may be a single layer or may be composed of two or more layers.

  The lithium ion secondary battery of this invention contains the lithium ion battery exterior material of this invention. The lithium ion secondary battery using the battery exterior material containing the modified polyolefin resin of the present invention may have a structure in which, for example, a positive electrode, a negative electrode, a nonaqueous electrolyte, and a separator are packaged with the battery exterior material of the present invention. That's fine.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to these.

Example 1
Propylene-ethylene copolymer (propylene component 88 mol%, ethylene component 12 mol%, weight average molecular weight 150,000, Tm = 74 ° C.) 100 in a four-necked flask equipped with a stirrer, a condenser, and a dropping funnel After dissolving the parts by weight in 400 g of toluene, while maintaining the temperature in the system at 110 ° C. and stirring, 1.5 parts by weight of maleic anhydride, 1.8 parts by weight of lauryl methacrylate, di-t-butyl 1 part by weight of peroxide was added dropwise over 3 hours, and the reaction was further continued for 1 hour. After the reaction, after cooling to room temperature, the reaction product was poured into a large excess of acetone for purification, the weight average molecular weight was 125,000, Tm = 74 ° C., the graft weight of maleic anhydride was 1.3% by weight, A modified polyolefin resin having a graft weight of lauryl methacrylate of 1.6% by weight was obtained.

The graft weight of maleic anhydride was measured by an alkali titration method, and the graft weight of lauryl methacrylate was measured by ¹ H-NMR.

(Example 2)
Propylene-butene copolymer (propylene component 80 mol%, butene component 20 mol%, weight average molecular weight 250,000, Tm = 88 ° C) 100 parts by weight, maleic anhydride 3.5 parts by weight, octyl methacrylate 3.5 parts by weight Part and 2 parts by weight of dilauryl peroxide were subjected to a kneading reaction using a twin screw extruder set at 170 ° C. Degassing under reduced pressure in the extruder to remove the remaining unreacted materials, the weight average molecular weight is 180,000, Tm = 88 ° C., the graft weight of maleic anhydride is 3.1% by weight, the graft weight of octyl methacrylate Of 3.0% by weight was obtained.

(Comparative Example 1)
The propylene-ethylene copolymer of Example 1 was modified in the same manner as in Example 1 except that the weight average molecular weight was 90,000. The resulting modified polyolefin resin had a weight average molecular weight of 75,000, Tm = 74 ° C., a graft weight of maleic anhydride of 1.3% by weight, and a graft weight of lauryl methacrylate of 1.5% by weight.

(Comparative Example 2)
The propylene-ethylene copolymer of Example 1 was modified in the same manner as in Example 1 except that the propylene component was 92 mol%, the ethylene component was 8 mol%, the weight average molecular weight was 220,000, and Tm was 120 ° C. The resulting modified polyolefin resin had a weight average molecular weight of 165,000, Tm = 120 ° C., a maleic anhydride graft weight of 1.1% by weight, and a lauryl methacrylate graft weight of 1.3% by weight.

(Comparative Example 3)
Modification was performed in the same manner as in Example 2 except that 0 part by weight of octyl methacrylate in Example 2 was used. The resulting modified polyolefin resin had a weight average molecular weight of 88,000, Tm = 88 ° C., and a maleic anhydride graft weight of 2.9% by weight.

(Evaluation test)
About the modified polyolefin resin obtained in Examples 1-2 and Comparative Examples 1-3, a cyclohexane solution sample was prepared so that it might become 15 weight%, respectively, In Example 1 and Comparative Examples 2-3, hexamethylene diisocyanate (Containing 1 wt% dibutyltin dilaurate) was uniformly mixed so that the equivalent ratio [isocyanate group / carboxyl group] = 1.5. In Example 2 and Comparative Example 1, isophorone diamine was equivalent to [amino group / carboxyl group]. ] Uniform mixing so as to be 1.5. Table 1 shows the results of performance evaluation of the obtained solution samples according to the following procedure.

<Test 1: Solution stability test>
The solution sample was put in a sealed glass bottle and stored at 5 ° C. for 7 days, and then visually evaluated for appearance.

<Test 2: Laminate adhesive strength test>
The solution sample was applied as an adhesive with a # 16 Meyer bar so that the resin dry film thickness was 2 μm on the aluminum foil and dried at 180 ° C. for 10 seconds. The coated aluminum foil was bonded to an unstretched polypropylene (CPP) sheet and thermocompression bonded under conditions of 200 kPa at 120 ° C. for 3 seconds to prepare a test piece cut out to a width of 15 mm. After the test piece was stored at 23 ° C. and 50% relative humidity for 24 hours at constant temperature and humidity, the laminate adhesive strength was measured under the conditions of 180-degree direction peeling and peeling speed of 100 mm / min.

<Test 3: Electrolytic solution resistance test>
The electrolytic solution used was ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1: 1: 1 (weight ratio) to which lithium hexafluorophosphate was added at a concentration of 1 mol / L. A test piece prepared in the same manner as in Test 1 was immersed in the electrolyte solution at 70 ° C. for 7 days, and the laminate adhesive strength was measured in the same manner as in Test 1.

  As is apparent from Table 1, the modified polyolefin resin provided by the present invention is excellent in the adhesion between the metal foil and the resin film constituting the lithium ion battery exterior, has durability against the electrolyte, It has low-temperature storage stability at the same time.

100, 200 Battery exterior material 11, 21 Outer layer 12, 22 Adhesive layer 13, 23 Intermediate layer (barrier layer)
14 Adhesive layers 15, 24 Inner layer

Claims (3)

Component (A): Polyolefin resin contains component (B): α, β-unsaturated carboxylic acid or derivative thereof, and component (C): modified polyolefin resin graft-modified with (meth) acrylic acid ester And
The melting point of the modified polyolefin resin by differential scanning calorimeter (DSC) is 74 ° C. to 88 ° C., and the weight average molecular weight is 125,000 to 180,000,
When the grafted weight of component (B) is 100% by weight of the modified polyolefin resin, it is 1.3 to 3.1% by weight, and
When the graft weight of the component (C) is 100% by weight of the modified polyolefin resin, it is 1.6 to 3.0% by weight.
Having solvent resistance, aluminum member coated and / or aluminum member modified polyolefin resin for lamination. Component (C) is a modified polyolefin resins according to claim 1 comprising a compound represented by at least the formula (I).
CH ₂ = CR ₁ COOR ₂ (I)
(In the formula (I), R ₁ = H or _{CH 3, R 2 = C n} H 2n + 1, n = 8~18 integer)   The component (A) includes at least one selected from the group consisting of an ethylene-propylene copolymer, a propylene-1-butene copolymer, and an ethylene-propylene-1-butene copolymer. Modified polyolefin resin.

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