Adhesive polymer composition, monolayer film, laminate, method for producing laminate, and lithium ion battery packaging material

Abstract

To provide an adhesive polymer composition whose adhesive strength at high temperature markedly decreases in comparison with its adhesive strength at normal temperature.SOLUTION: Provided is an adhesive polymer composition, which comprises, as polymer components, at least components (A) to (C), wherein, when the combined content of component (B) and component (C) is set as 100 pts.mass, the proportion of component (B) falls within 30 to 77 pts.mass. Component (A): a modified polypropylene in which at least one unsaturated carboxylic acid and / or a derivative thereof has been grafted onto a propylene-based polymer. Component (B): an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer having an α-olefin content of 5.8 mol% or more. Component (C): either a propylene homopolymer, or a propylene-α-olefin copolymer having an α-olefin content of less than 5.8 mol%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive polymer composition, a monolayer film, a laminate, a method for producing a laminate, and an exterior material for a lithium ion battery. [Background technology]

[0002] Lithium ion batteries, including lithium ion secondary batteries, are widely used as power sources for devices such as laptop computers, video cameras, mobile phones, and electric vehicles. These lithium ion batteries have a structure in which a battery body (a body containing a positive electrode, a negative electrode, and an electrolyte) is enclosed in a case. Known examples of the case material (exterior material) include an outer layer made of a heat-resistant polymer film, an aluminum foil layer, and an inner layer made of a thermoplastic polymer film, which are bonded together in this order.

[0003] However, in lithium-ion batteries, gas is likely to be generated in the battery body during overcharging or excessive temperature rise, and as a result, the gas gradually accumulates in the internal space covered by the exterior material, which can cause an increase in the internal pressure of the exterior material.If the increase in internal pressure becomes excessive, the exterior material may burst, raising concerns that the contents inside may be scattered.Therefore, technologies have been proposed to prevent such rupture of the exterior material.

[0004] For example, Patent Document 1 discloses the use of an adhesive polymer composition that has adhesive properties to metals, polymers, etc. and excellent low-temperature processability between the tab lead and the exterior material. A structure has been studied that prevents an abnormal increase in internal pressure by reducing the adhesive strength of the adhesive polymer composition as the temperature rises and releasing pressure from between the tab lead and the exterior material. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-29260 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the adhesive polymer composition described in Patent Document 1 does not provide sufficient effects, and there is room for improvement in the area of ​​the decrease in adhesive strength due to temperature rise. Therefore, an object of the present invention is to provide an adhesive polymer composition whose adhesive strength at high temperatures is significantly reduced compared to its adhesive strength at room temperature. [Means for solving the problem]

[0007] The present inventors have conducted extensive research to solve the above-mentioned problems, and have found that the above-mentioned problems can be solved by providing an adhesive polymer composition containing at least the following components (A) to (C) as polymer components, in which the content of component (B) is 30 to 77 parts by mass when the total content of components (B) and (C) is 100 parts by mass, and have thus completed the present invention. Component (A): Modified polypropylene in which at least one unsaturated carboxylic acid or its derivative, or both, is grafted onto a propylene polymer. Component (B): Ethylene / α-olefin copolymer or propylene / α-olefin copolymer with an α-olefin content of 5.8 mol% or more Component (C): Propylene homopolymer or propylene-α-olefin copolymer with an α-olefin content of less than 5.8 mol%

[0008] That is, the present invention provides the following.

[0009] Aspect 1 of the present invention is The polymer component contains at least the following components (A) to (C): The adhesive polymer composition relates to a composition in which the content of the component (B) is 30 to 77 parts by mass when the total content of the component (B) and the component (C) is 100 parts by mass. Component (A): Modified polypropylene in which at least one unsaturated carboxylic acid or its derivative, or both, is grafted onto a propylene polymer. Component (B): Ethylene / α-olefin copolymer or propylene / α-olefin copolymer with an α-olefin content of 5.8 mol% or more Component (C): Propylene homopolymer or propylene-α-olefin copolymer with an α-olefin content of less than 5.8 mol%

[0010] A second aspect of the present invention is the adhesive polymer composition of the first aspect, The adhesive polymer composition has a maleic acid modification amount of 0.05 to 0.25% by mass, which is represented by the following formula (X): [Maleic Acid Modification Amount (% by Mass) of Adhesive Polymer Composition] = [amount of maleic acid modification of component (A) (mass%)] × [mass of component (A) (g)] / [mass of polymer component (g)] Formula (X)

[0011] A third aspect of the present invention relates to the adhesive polymer composition of the first or second aspect, The adhesive polymer composition has a content of the component (A) of 1 to 30 parts by mass when the total content of the component (B) and the component (C) is taken as 100 parts by mass.

[0012] A fourth aspect of the present invention is The present invention relates to a monolayer film comprising the adhesive polymer composition according to any one of the first to third embodiments.

[0013] A fifth aspect of the present invention is The present invention relates to a laminate comprising an adhesive layer containing the adhesive polymer composition according to any one of Embodiments 1 to 3, and a substrate layer.

[0014] A sixth aspect of the present invention relates to the laminate of the fifth aspect, The present invention relates to a laminate, wherein the substrate layer is made of a metal material or a composite material of a metal and a polymer.

[0015] A seventh aspect of the present invention is The present invention relates to a method for producing a laminate, which includes a step of sandwiching the monolayer film of embodiment 4 and a substrate between heated rolls and thermocompressing them together.

[0016] Aspect 8 of the present invention is the production method of aspect 7, further comprising: The present invention relates to a manufacturing method in which the substrate is made of a metal material or a composite material of a metal and a polymer.

[0017] A ninth aspect of the present invention is The present invention relates to an exterior material for a lithium ion battery, including the laminate of embodiment 6. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide an adhesive polymer composition whose adhesive strength at high temperatures is significantly reduced compared to its adhesive strength at room temperature. DETAILED DESCRIPTION OF THE INVENTION

[0019] The following describes in detail the embodiments of the present invention, but the following embodiments are merely examples of the present invention and the present invention is not limited thereto. The present invention can be carried out in any modified form without departing from the gist of the present invention. In this specification, when "~" is used to express a numerical value or a physical property value, the values ​​before and after the "~" are included.

[0020] [Adhesive polymer composition] The adhesive polymer composition according to the present embodiment contains at least the following components (A) to (C) as polymer components, and the content of the component (B) is 30 to 77 parts by mass when the total content of the component (B) and the component (C) is 100 parts by mass. Component (A): Modified polypropylene in which at least one unsaturated carboxylic acid or its derivative, or both, is grafted onto a propylene polymer. Component (B): Ethylene / α-olefin copolymer or propylene / α-olefin copolymer with an α-olefin content of 5.8 mol% or more Component (C): Propylene homopolymer or propylene-α-olefin copolymer with an α-olefin content of less than 5.8 mol%

[0021] <Mechanism> In the adhesive polymer composition according to this embodiment, it is believed that the effects of the present invention are achieved by components (A) to (C) each fulfilling the following roles: Component (A) exhibits a reactive adhesive mechanism; Component (B) imparts flexibility and contributes to stress relaxation, improving adhesive strength, and contributes to a decrease in crystallinity, thereby reducing adhesiveness in high-temperature environments; and Component (C) provides mechanical strength and heat resistance.

[0022] Conventional adhesive polymer compositions used for laminates include those containing an appropriate blend of the above-mentioned components (A) to (C), etc. In contrast, the adhesive polymer composition according to the present embodiment, which contains a predetermined amount of component (B), has been able to achieve a property in which the adhesive strength at high temperatures is significantly reduced compared to the adhesive strength at room temperature.

[0023] The reason for this effect is unclear, but it is thought to be as follows: Component (B), in combination with components (A) and (C), can impart flexibility to the adhesive polymer composition, and furthermore, it is thought that the breakdown of crystallinity can bring about a rapid decrease in adhesiveness in a high-temperature atmosphere.

[0024] <Component (A)> Component (A) in this embodiment is a modified polypropylene in which at least one unsaturated carboxylic acid or a derivative thereof, or both of these (hereinafter also referred to as "unsaturated carboxylic acid and / or a derivative thereof") is grafted onto polypropylene. Here, "grafting" can also be referred to as "graft modification," and means bonding an unsaturated carboxylic acid and / or a derivative thereof to a propylene-based polymer. The bonding position of the unsaturated carboxylic acid and / or a derivative thereof in the modified propylene-based polymer is not particularly limited, as long as it is introduced into at least one of the main chain terminal and the side chain of the propylene-based polymer.

[0025] The propylene polymer used as the raw material for component (A) according to this embodiment is not limited as long as it has a propylene unit content of more than 50% by mass, i.e., a content of monomer units other than propylene of less than 50% by mass. The propylene monomer unit content is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0026] The propylene polymer is not particularly limited as long as it has a propylene unit content of more than 50% by mass, and examples thereof include propylene homopolymers, propylene-ethylene copolymers, propylene-1-butene copolymers, propylene-ethylene-1-butene copolymers, propylene-4-methyl-1-pentene copolymers, copolymers of propylene with ethylene and / or other α-olefins, and copolymers of propylene with other vinyl monomers. The other α-olefins, i.e., α-olefins other than propylene, are not particularly limited, but typically include hydrocarbons having 4 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and having a double bond. The "other vinyl monomers" are also not particularly limited, but examples thereof include vinyl acetate, vinyl alcohol, (meth)acrylic acid, (meth)acrylic acid alkyl esters, styrene, and styrene derivatives. The propylene polymer may be one of the above polymers or a mixture of two or more of them.

[0027] The copolymers may be any of block copolymers, graft copolymers, random copolymers, and the like. Among these, the propylene-based polymer is preferably a propylene homopolymer, a propylene-ethylene copolymer, or a blend thereof, and more preferably a propylene homopolymer.

[0028] The density of the propylene polymer measured by the underwater displacement method in accordance with JIS K 7112:1999 is 0.860 to 0.910 g / cm in order to obtain excellent moldability and strength. 3is preferable, and 0.861 to 0.909 g / cm 3 More preferably, 0.862 to 0.908 g / cm 3 is more preferable. The density of propylene polymer is 0.860 g / cm 3 A density of 0.910 g / cm or more is preferable for maintaining heat resistance and material strength. 3 It is preferable that the thickness is not more than this in order to ensure moldability and flexibility.

[0029] The MFR (230°C, load 21.2 N, orifice diameter 2 mm) of the propylene polymer measured in accordance with JIS K 7210:2014 is not particularly limited, but from the viewpoints of uniform mixing with other components and high-speed moldability, it is usually 0.5 to 50 g / 10 min, preferably 1 to 30 g / 10 min, and more preferably 2 to 25 g / 10 min.

[0030] The flexural modulus of the propylene polymer is not particularly limited, but is usually in the range of 30 to 2000 MPa, and is preferably 500 MPa or more in order to maintain mechanical strength and make the material less susceptible to fracture. Furthermore, the flexural modulus is preferably 2000 MPa or less in order to ensure adequate wettability at the bonding surface and make the adhesion less likely to decrease.

[0031] The unsaturated carboxylic acid used for graft-modifying the propylene polymer is preferably an α,β-ethylenically unsaturated carboxylic acid, such as acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, tetrahydrofumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, etc. Derivatives of unsaturated carboxylic acids include acid anhydrides and carboxylic acid esters of these unsaturated carboxylic acids, and may also be derivatives such as acid halides, amides, and imides. Of these derivatives, acid anhydrides are preferred.

[0032] Among these, maleic acid and / or its anhydride are particularly suitable. A plurality of these compounds may be used in combination. Furthermore, vinyl silanes such as vinyltrimethoxysilane may also be used in combination with the unsaturated carboxylic acid and / or its derivative.

[0033] The graft modification to obtain the modified polypropylene of component (A) according to this embodiment can be carried out by a known method. For example, the modified polypropylene can be obtained by a reaction using heat alone, or an organic peroxide or the like that generates radicals during the reaction can be added as a radical generator. Examples of reaction methods include a solution modification method in which the reaction is carried out in a solvent, and a melt modification method that does not use a solvent. Furthermore, other methods such as a suspension dispersion reaction method can also be used.

[0034] Examples of melt modification methods that can be used include a method in which a propylene polymer, an unsaturated carboxylic acid and / or a derivative thereof, and, if necessary, a radical generator described below are mixed in advance and then melt-kneaded in a kneader to cause a reaction, and a method in which a mixture of a radical generator and an unsaturated carboxylic acid and / or a derivative thereof is added to a propylene polymer molten in a kneader through an inlet to cause a reaction, etc. A Henschel mixer, ribbon blender, V-type blender, etc. can be used for mixing, and a single-screw or twin-screw extruder, roll, Banbury mixer, kneader, Brabender mixer, etc. can be used for melt-kneading.

[0035] The solution modification method may involve dissolving a propylene polymer in an organic solvent or the like, adding a radical generator and an unsaturated carboxylic acid and / or a derivative thereof, and graft-copolymerizing the resulting solution. The organic solvent is not particularly limited, and examples of the organic solvent that may be used include alkyl-substituted aromatic hydrocarbons and halogenated hydrocarbons.

[0036] The blending ratio of the propylene-based polymer and the unsaturated carboxylic acid and / or derivative thereof is not particularly limited, but it is desirable to blend the unsaturated carboxylic acid and / or derivative thereof in an amount of usually 0.01 to 30 parts by mass, preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 5 parts by mass per 100 parts by mass of the propylene-based polymer.

[0037] The radical generator is not particularly limited, and examples thereof include dialkyl peroxides such as di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, 1,4-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, 2,2-bis(4,4-t-butylperoxycyclohexyl)propane, 2,2-bis(t-butylperoxy)butane, and 1,1-bis(t-butylperoxy)cyclododecane, t-butyl peroxyacetate, t-butylperoxy-2-ethylhexanoate, t-butyl peroxypivalate, t-butyl peroxylaurate, t-butyl peroxybenzoate, and t-butyl peroxybenzoate. Examples of the peroxyesters include ethyl peroxyisopropyl carbonate, t-butyl peroxymaleic acid, di-t-butyl peroxyisophthalate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di(benzoylperoxy)hexyne-3, and 2,5-dimethyl-2,5-di(toluylperoxy)hexane; diacyl peroxides such as di-3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, and dibenzoyl peroxide; hydroperoxides such as t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, and 2,5-dimethyl-2,5-di(hydroperoxy)hexane; and ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide. These may be used alone or in combination of two or more.

[0038] These radical generators can be appropriately selected depending on the type and MFR of the raw propylene polymer, the type of unsaturated carboxylic acid and / or its derivative, the reaction conditions, etc., and two or more types may be used in combination. The amount of the radical generator to be added is not particularly limited, but is usually 0.001 to 20 parts by mass, preferably 0.005 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and particularly preferably 0.01 to 3 parts by mass, per 100 parts by mass of the propylene polymer.

[0039] The amount of modification (graft rate) with unsaturated carboxylic acid and / or its derivative in the modified polypropylene of component (A) in this embodiment is not particularly limited, but from the viewpoint of adhesion to the base layer, it is usually 0.01 mass% or more, preferably 0.1 mass% or more, and more preferably 0.3 mass% or more, while from the viewpoint of thermal stability and compatibility with other components, it is usually 10 mass% or less, preferably 7 mass% or less, and more preferably 5 mass% or less.

[0040] Here, the modification amount (graft ratio) means the content of unsaturated carboxylic acid and / or its derivative components when measured with an infrared spectrometer. For example, the absorption specific to carboxylic acid and / or its derivatives in a sample press-molded into a sheet having a thickness of about 100 μm, specifically, 1900 to 1600 cm -1 The mass of the grafted portion structure is calculated from the measured value thus obtained, and the graft ratio is the proportion of the mass of the grafted portion structure when the modified polypropylene is taken as 100% by mass. In addition, in the modification with the unsaturated carboxylic acid and / or its derivative, 100% may not be subjected to the reaction, and unsaturated carboxylic acid and / or its derivative that has not reacted with the propylene polymer may remain in the modified polypropylene. However, the modification amount (graft ratio) in this embodiment means the value measured by the above method.

[0041] Furthermore, component (A) according to this embodiment can be treated to remove unreacted unsaturated carboxylic acid and / or its derivatives. While the method for this treatment is not particularly limited, a specific example is a method in which the modified polypropylene is placed in a storage tank configured to allow gas to be blown in from the bottom of the device, the device is heated to about 100°C using a heater or thermal oil, and an inert gas such as nitrogen or air is blown in from the bottom of the device for 6 to 24 hours.

[0042] The modified polypropylene of component (A) according to the present embodiment may be used alone, or two or more types may be mixed and used, which differ in the monomer composition or physical properties of the propylene polymer, the type of unsaturated carboxylic acid and / or its derivative used for graft modification, or the degree of modification.

[0043] In this embodiment, when the total content of component (A) and components (B) to (C) described below is taken as 100 parts by mass, the content of component (A) is preferably 0.5 to 35% by mass, more preferably 1 to 25% by mass, and even more preferably 2 to 20% by mass. When the total content of components (A) to (C) is taken as 100 parts by mass, the content of component (A) is preferably 0.5% by mass or more, since a sufficient adhesive reaction can be expected, and if it is 35% by mass or less, inhibition of required properties other than adhesiveness can be avoided.

[0044] In addition, when unsaturated carboxylic acid and / or derivative thereof that has not reacted with the propylene polymer remains in component (A), the content of component (A) and the total content of components (A) to (C) are values ​​including the remaining unsaturated carboxylic acid and / or derivative thereof. The same applies to the content of component (A) and the total content of components (A) to (C) discussed hereinafter in this specification.

[0045] Furthermore, when the total content of components (B) and (C) is taken as 100 parts by mass, the content of component (A) is preferably 1 to 30 parts by mass, more preferably 2 to 25 parts by mass, and even more preferably 3 to 20 parts by mass. When the total content of components (B) and (C) is 100 parts by mass, it is preferable that the content of component (A) is 1 part by mass or more, since a sufficient adhesive reaction can be expected, and it is preferable that the content is 30 parts by mass or less, since it avoids the inhibition of desired properties other than adhesiveness.

[0046] <Ingredient (B)> Component (B) according to this embodiment is an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer having an α-olefin content of 5.8 mol % or more.

[0047] In the ethylene-α-olefin copolymer or propylene-α-olefin copolymer of component (B) according to this embodiment, the α-olefin content is 5.8 mol% or more, preferably 5.9 mol% or more, and more preferably 6.0 mol% or more. There is no upper limit to the α-olefin content, but it is preferably 25 mol% or less, and more preferably 24 mol% or less. Furthermore, if the content of α-olefin is 25 mol % or less, an excessive decrease in adhesive strength at room temperature is desired, which is preferable.

[0048] When the total content of components (B) and (C) is 100 parts by mass, the content of component (B) is 30 to 77 parts by mass, preferably 31 to 76 parts by mass, and more preferably 33 to 75 parts by mass. When the total content of components (B) and (C) is 100 parts by mass, the content of component (B) is 30 parts by mass or more, which is expected to result in a sufficient decrease in adhesion in a high-temperature atmosphere. Furthermore, when the content of component (B) is 77 parts by mass or less, excessive decrease in adhesion at room temperature can be prevented.

[0049] (Ethylene-α-olefin copolymer) The α-olefins other than ethylene that can be used as raw materials for the ethylene-α-olefin copolymer of component (B) according to this embodiment are not limited, but examples include α-olefins having approximately 3 to 10 carbon atoms, such as propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene. The ethylene-α-olefin copolymer may contain other monomer units, such as vinyl acetate, vinyl alcohol, (meth)acrylic acid, (meth)acrylic acid alkyl ester, styrene, and styrene derivatives.

[0050] The melt flow rate (230°C, load 2.12 N, orifice diameter: 2 mm) of the ethylene-α-olefin copolymer of component (B) according to this embodiment is not limited, but is typically 0.5 g / 10 min or more, preferably 1 g / 10 min or more, and more preferably 2 g / 10 min or more. On the other hand, it is typically 50 g / 10 min or less, preferably 35 g / 10 min or less, and more preferably 25 g / 10 min or less. A melt flow rate of 0.5 g / 10 min or more of the ethylene-α-olefin copolymer is preferred because it ensures a certain degree of compatibility with other components. Furthermore, a melt flow rate of 50 g / 10 min or less is preferred because it ensures a certain degree of moldability.

[0051] In this embodiment, the density of the ethylene-α-olefin copolymer is not limited, but is usually 0.895 g / cm 3 or less, preferably 0.880 g / cm 3 The density of the ethylene-α-olefin copolymer is preferably 0.895 g / cm or less. 3 A density of 0.860 g / cm or less is preferable because flexibility is imparted and a decrease in adhesion in a high-temperature atmosphere is expected. Although there is no lower limit for the density, it is usually 0.860 g / cm 3 That's all.

[0052] As such an ethylene-α-olefin copolymer, a commercially available product can be used, and for example, one having the above-mentioned properties can be appropriately selected from the TAFMER series manufactured by Mitsui Chemicals, Inc.

[0053] (propylene-α-olefin copolymer) The α-olefin constituting the propylene-α-olefin copolymer is not limited, but specific examples include 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, etc. Among these, α-olefins having 4 to 8 carbon atoms are preferred. Furthermore, the propylene-α-olefin copolymer may contain other monomer units, specifically the same monomer units as those mentioned for the ethylene-α-olefin copolymer.

[0054] Other preferable properties of the propylene-α-olefin copolymer are the same as those described for the ethylene-α-olefin copolymer.

[0055] As such a propylene-α-olefin copolymer, a commercially available product can be used, and for example, one having the above-mentioned properties can be appropriately selected from Vistamax manufactured by Exxon Corporation.

[0056] <Ingredient (C)> Component (C) according to this embodiment is a propylene homopolymer or a propylene-α-olefin copolymer having an α-olefin content of less than 5.8 mol %.

[0057] (propylene homopolymer) As the propylene homopolymer of component (C) according to this embodiment, a commercially available product can be used, and for example, one having the above-mentioned properties can be appropriately selected from the Novatec series manufactured by Japan Polypropylene Corporation.

[0058] The melt flow rate (MFR) of the propylene homopolymer of component (C) according to this embodiment is not particularly limited, but is typically 0.5 to 50 g / 10 min, preferably 1 to 30 g / 10 min, and more preferably 2 to 25 g / 10 min, under conditions of 230°C, a load of 2.12 N, and an orifice diameter of 2 mm. An MFR of 0.5 g / 10 min or more is preferred because it ensures a certain degree of compatibility with other components. An MFR of 50 g / 10 min or less is also preferred because it ensures a certain degree of moldability.

[0059] Other preferred properties of the propylene homopolymer are the same as those described for the ethylene-α-olefin copolymer.

[0060] (propylene-α-olefin copolymer) In the propylene-α-olefin copolymer of component (C) according to this embodiment, the α-olefin content is less than 5.8 mol %, preferably 5.7 mol % or less, and more preferably 5.6 mol % or less.

[0061] The preferred properties of the propylene-α-olefin copolymer of component (C) according to this embodiment are the same as those described for the ethylene-α-olefin copolymer of component (B).

[0062] <Other ingredients> The adhesive polymer composition according to the present embodiment may contain additives, polymers, etc. (hereinafter, sometimes referred to as "other components") in addition to the components described above, as long as the effects of the present invention are not significantly impaired. The other components may be used alone or in any combination and ratio of two or more.

[0063] The additives that can be used in the adhesive polymer composition according to the present embodiment are not particularly limited, but specific examples include heat stabilizers, weather stabilizers (antioxidants, light stabilizers, UV absorbers, etc.), flame retardants, antiblocking agents, slip agents, antistatic agents, fillers (inorganic and / or organic fillers, etc.), processing aids, plasticizers, nucleating agents, impact modifiers, compatibilizers, neutralizers for catalyst residues, carbon black, colorants (pigments, dyes, etc.), etc. When these additives are used, their content is not particularly limited, but it is desirable that they be contained in an amount of typically 0.01% by mass or more, preferably 0.2% by mass or more, and typically 5% by mass or less, preferably 2% by mass or less, of the total amount of the adhesive polymer composition.

[0064] The polymer used as the other component is not particularly limited, but examples thereof include polyphenylene ether; polycarbonate; polyamides such as nylon 66 and nylon 11; polyesters such as polyethylene terephthalate and polybutylene terephthalate; styrene-based polymers such as polystyrene; and acrylic / methacrylic polymers such as polymethyl methacrylate-based polymers.

[0065] <Preferred Embodiments of Adhesive Polymer Composition> (Maleic acid modification amount) In the adhesive polymer composition according to this embodiment, the amount of maleic acid modification represented by the following formula (X) is preferably 0.05 to 0.25 mass %, more preferably 0.06 to 0.24 mass %, and even more preferably 0.07 to 0.23 mass %. [Maleic Acid Modification Amount (% by Mass) of Adhesive Polymer Composition] = [amount of maleic acid modification of component (A) (mass%)] × [mass of component (A) (g)] / [mass of polymer component (g)] Formula (X)

[0066] The term "polymer component" as used herein means a polymer component contained in the adhesive polymer composition, and includes the above components (A) to (C) as well as the polymers listed as the other components.

[0067] The maleic acid modification amount represented by the formula (X) is preferably 0.05% by mass or more, since sufficient adhesive strength is desired to be exhibited, and is preferably 0.25% by mass or less, since poor appearance of the molded article can be avoided.

[0068] (peel strength retention rate) The adhesive polymer composition according to this embodiment exhibits a characteristic in which the adhesive strength under high temperature conditions is significantly reduced compared to the adhesive strength at room temperature. Such a characteristic can be evaluated, for example, by the ratio of the peel strength at room temperature to the peel strength in a high-temperature atmosphere. The adhesive polymer composition according to this embodiment has a low ratio of the peel strength in a high-temperature atmosphere to the peel strength at room temperature (peel strength retention rate).

[0069] <Method for producing adhesive polymer composition> The adhesive polymer composition according to this embodiment can be obtained by mixing the above-mentioned components in a predetermined ratio. The mixing method is not particularly limited as long as the raw material components are uniformly dispersed. That is, the raw material components described above can be mixed simultaneously or in any order to obtain a composition in which the components are uniformly dispersed.

[0070] For more uniform mixing and dispersion, it is preferable to melt-mix predetermined amounts of the raw material components. For example, the raw material components of the adhesive polymer composition according to the present embodiment may be mixed in any order and then heated, or all of the raw material components may be mixed while melting sequentially, or a mixture of the raw material components may be pelletized or melt-mixed during molding to produce the desired molded product.

[0071] The adhesive polymer composition according to the present embodiment can be prepared by various known methods, such as mixing predetermined amounts of the above-mentioned raw material components using a tumbler blender, V blender, ribbon blender, Henschel mixer, etc., and then melt-kneading and granulating or pulverizing the mixture using a single-screw extruder, twin-screw extruder, Banbury mixer, kneader, etc. The temperature during melt-kneading may be any temperature at which at least one of the raw material components is in a molten state, but a temperature at which all of the components used are melted is usually selected, and is generally in the range of 150 to 300°C.

[0072] [Laminate and method for manufacturing laminate] <Molded articles and monolayer films obtained from adhesive polymer compositions> There is no limitation on the molded article obtained from the adhesive polymer composition according to the present embodiment, and various extrusion molded articles and injection molded articles can be obtained. Specifically, a monolayer film containing the adhesive polymer composition according to the present embodiment can be mentioned.

[0073] The monolayer film according to this embodiment may be a monolayer film (I) made of the adhesive polymer composition according to this embodiment, or a monolayer film (II) containing the adhesive polymer composition according to this embodiment and other components. Here, the other components optionally include an olefin-based polymer different from the components of the adhesive polymer composition according to this embodiment. For example, the monolayer film (II) may contain the adhesive polymer composition according to this embodiment and an olefin-based polymer different from the components of the adhesive polymer composition according to this embodiment.

[0074] The monolayer film (II) may be obtained by molding a mixture obtained by dry-mixing the adhesive polymer composition according to this embodiment with other components. Such a monolayer film (II) can be obtained, for example, by a method for producing a monolayer film, which includes a step of dry-mixing the adhesive polymer composition according to this embodiment with other components to form a dry mixture, and a step of molding the mixture to obtain a monolayer film.

[0075] There is no particular limitation on the thickness of such a single layer film (I) or a single layer film (II), but it is usually about 5 to 500 μm.

[0076] [Laminate and method for manufacturing laminate] The laminate according to this embodiment can be a laminate including an adhesive layer containing the adhesive polymer composition according to this embodiment described above and a substrate layer. Examples of the laminate include laminates having two or more layers stacked together, and specific examples include laminate sheets, laminate films, and laminate tubes. Here, the terms "sheet" and "film" both mean planar molded articles and are synonymous.

[0077] The material constituting the base layer of the laminate according to this embodiment is not particularly limited, but is preferably a polymer layer, a metal material, or a composite material of metal and polymer, and more preferably a metal material or a composite material of metal and polymer.

[0078] The adhesive layer made of the adhesive polymer composition according to this embodiment and the substrate layer are preferably adjacent to each other.

[0079] As a method for producing the laminate according to the present embodiment, various known methods can be adopted, but extrusion lamination is particularly suitable. Extrusion lamination is a molding method in which a melt of an adhesive polymer composition is extruded into a film shape, cast onto a substrate, and then sandwiched between rolls to bond the film under pressure.

[0080] As the monolayer film of the adhesive polymer composition for forming the adhesive layer, a monolayer film (I) made of the adhesive polymer composition according to the present embodiment described above, or a monolayer film (II) obtained from a mixture obtained by dry-mixing the adhesive polymer composition according to the present embodiment with other components can be used. The method for producing a laminate according to the present embodiment may include, for example, a step of sandwiching the monolayer film and a substrate between heated rolls and thermocompressing them together. The substrate may be made of a metal material or a composite material of a metal and a polymer.

[0081] When the substrate layer is a polymer layer, the polymer layer is preferably obtained as a polymer film or sheet. The polymer constituting the polymer film or sheet is not particularly limited, but specifically, thermoplastic polymers such as olefin-based polymers and olefin-based elastomers including ethylene-vinyl alcohol copolymers, ethylene-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride, polyethylene, polypropylene, poly-4-methyl-1-pentene, polycarbonate, polyamides such as polyamide 6, polyamide 66, polyamide 6-66, and polyamide 12, polyesters and polyester-based elastomers such as polyethylene terephthalate and polybutylene terephthalate, styrene-based polymers and styrene-based elastomers, and acrylic polymers are preferably used. Among these, when used as a material for food or medical applications, it is preferable to have at least a polyester layer, an ethylene-vinyl alcohol copolymer layer, or a polyamide layer, and more preferably to have at least a polyester layer. These polymer layers may be laminated with two or more types of polymer layers.

[0082] When the substrate layer is made of a metal material or a composite material of a metal and a polymer, the metal layer is preferably obtained as a film or sheet made of a metal material or a composite material of a metal and a polymer. Suitable metals include aluminum, stainless steel, copper, and titanium. Suitable polymers include propylene polymers, ethylene polymers, ester polymers, and nylon polymers.

[0083] The form of the substrate is not limited to a film or a sheet, and may be a woven fabric or a nonwoven fabric. The substrate may have a single-layer structure or a multi-layer structure. The method for producing a multi-layer substrate is not particularly limited, and examples thereof include a co-extrusion film method, a dry lamination method, a wet lamination method, a hot-melt lamination method, an extrusion lamination method, and a thermal lamination method.

[0084] There is no particular limitation on the thickness of such a substrate layer, but it is usually about 5 to 150 μm.

[0085] The thickness of each layer of the laminate according to this embodiment is not limited and can be set arbitrarily depending on the layer configuration, application, shape of the final product, required physical properties, etc. The total thickness of the laminate is usually 5 to 400 μm, preferably 10 to 300 μm, and more preferably 20 to 200 μm. The thickness of the adhesive layer made of the adhesive polymer composition according to this embodiment that constitutes the laminate is usually 0.1 to 300 μm, preferably 1 to 250 μm, and more preferably 5 to 200 μm.

[0086] The laminate thus produced can be further subjected to various film processing treatments such as metal deposition, corona discharge treatment, and printing.

[0087] [Application] The adhesive polymer composition of this embodiment exhibits excellent adhesive strength properties to metal layers and polymer films, and therefore, a laminate of this embodiment using this composition is suitable for packaging various foods and beverages, pharmaceuticals and medical products, cosmetics, clothing, stationery, and other industrial materials such as batteries.

[0088] <Lithium-ion battery exterior materials> The adhesive polymer composition according to this embodiment further exhibits the property that the adhesive strength under high temperature conditions is significantly reduced compared to the adhesive strength at room temperature, and therefore the laminate according to this embodiment using this composition is particularly suitable for use as an exterior material for lithium ion batteries, where there is a concern that the exterior material may burst due to an excessive increase in internal pressure.

[0089] In one aspect, a lithium-ion battery exterior material includes the laminate according to the present embodiment. In one aspect, the laminate includes an adhesive layer containing the adhesive polymer composition according to the present embodiment and a substrate layer. The substrate layer is preferably made of a metal material or a composite material of a metal and a polymer.

[0090] An embodiment of such a lithium ion battery may have a laminated structure in which a layer having a laminated structure in which the lithium ion battery exterior material according to this embodiment and a metal tab lead are laminated, and a polar material layer are laminated. In such a lithium ion battery, the packaging material according to this embodiment can be used as a secondary battery member, for example, as a secondary battery packaging material. [Example]

[0091] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Note that the values ​​of various production conditions and evaluation results in the following examples represent preferred upper or lower limit values ​​in the embodiments of the present invention, and a preferred range may be defined by a combination of the above-mentioned upper or lower limit values ​​and the values ​​in the following examples or values ​​between the examples.

[0092] [Measurement and evaluation method] The raw materials used in the following examples and comparative examples, and the methods for measuring and evaluating the resulting adhesive polymer compositions and laminates are as follows.

[0093] (1) Melt flow rate (MFR) The MFR of the raw materials was measured in accordance with JIS K 7210:2014 under the conditions of a temperature of 230°C or 190°C, a load of 21.2N, and an orifice diameter of 2mm.

[0094] (2) Content of unsaturated carboxylic acid components The contents of the unsaturated carboxylic acid component in the modified polypropylene and adhesive polymer composition were determined as follows. Pellets of the modified polypropylene or adhesive polymer composition were press-molded (200°C) into a film having a thickness of 100 μm to prepare a sample. The prepared sample was subjected to infrared absorption spectroscopy using an FT-IR device (JASCOFT / IR610, manufactured by JASCO Corporation) to measure the absorption characteristic of carboxylic acid and / or its derivatives in the sample, specifically, the absorption band between 1900 and 1600 cm. -1 The content of unsaturated carboxylic acid components was calculated from the peak of the carbonyl characteristic absorption (C=O stretching vibration band) measured.

[0095] (3) Density Measurement was carried out by the water displacement method in accordance with JIS K 7112:1999.

[0096] (4) Measurement of comonomer content NMR measurement was carried out, and the comonomer content was calculated from the peak area corresponding to the comonomer.

[0097] [raw materials] In the following examples and comparative examples, the raw materials used in the production of adhesive polymer compositions are as follows:

[0098] <Component (A): Modified polypropylene> a-1 Modified polypropylene a-1 is a propylene-ethylene copolymer (density 0.874 g / cm 3 The modified polypropylene used was obtained by graft-modifying α-olefin ethylene unit (16 mol%) with maleic anhydride, MFR (230°C, load 21.2 N, orifice diameter: 2 mm): 2 g / 10 min, flexural modulus: 60 MPa, α-olefin ethylene unit content: 16 mol%). a-2 Modified polypropylene a-2 is a propylene-ethylene copolymer (density 0.890 g / cm 3 The modified polypropylene obtained by graft-modifying a terpolymer of 1,2-dimethyl-2,3-dimethyl-1,3-dimethyl-2 ... a-3 As modified polypropylene a-3, commercially available propylene homopolymer (density: 0.900 g / cm 3 The modified polypropylene obtained by graft-modifying a propylene copolymer (MFR: 230°C, load: 21.2N, orifice diameter: 2mm): 10g / 10min, flexural modulus: 1500MPa) with maleic anhydride was used.

[0099] <Component (B): Ethylene-α-olefin copolymer, propylene-α-olefin copolymer> b-1 As the ethylene-α-olefin copolymer b-1, an ethylene-propylene copolymer, TAFMER® P0775 (MFR (230°C, load 21.2 N, orifice diameter: 2 mm): 0.6 g / 10 min, density: 0.860 g / cm), manufactured by Mitsui Chemicals, Inc., was used. 3 The content of propylene units as α-olefin was 21.5 mol%. b-2 As the ethylene-α-olefin copolymer b-2, an ethylene-propylene copolymer, TAFMER® P0180 (MFR (230°C, load 21.2 N, orifice diameter: 2 mm): 8.1 g / 10 min, density: 0.870 g / cm), manufactured by Mitsui Chemicals, Inc., was used. 3 The content of propylene units as α-olefin was 18.6 mol%. b-3 As the ethylene-α-olefin copolymer b-3, an ethylene-propylene copolymer, TAFMER® P0280 (MFR (230°C, load 21.2 N, orifice diameter: 2 mm): 5.4 g / 10 min, density: 0.870 g / cm), manufactured by Mitsui Chemicals, Inc., was used. 3 The content of propylene units as α-olefin was 18.4 mol%. b-4 As the ethylene-α-olefin copolymer b-4, ENGAGE® 8480 (MFR (190°C, load 21.2 N, orifice diameter: 2 mm): 1.0 g / 10 min, density: 0.902 g / cm), an ethylene-octene copolymer manufactured by Dow, was used. 3 The content of octene units as α-olefin was 6.0 mol%.

[0100] <Component (C): Propylene homopolymer, propylene-α-olefin copolymer> c-1 As the propylene homopolymer c-1, Waymax (registered trademark) MFX8 (MFR (230°C, load 21.2 N, orifice diameter: 2 mm): 1.0 g / 10 min, density: 0.900 g / cm) manufactured by Japan Polyethylene Corporation was used. 3 ) was used. c-2 Propylene-α-olefin copolymer c-2 was prepared from propylene-ethylene copolymer (MFR (230°C, load 21.2 N, orifice diameter: 2 mm): 7.0 g / 10 min, density: 0.900 g / cm). 3 The content of ethylene units as α-olefin was 5.5 mol%. c-3 Propylene-α-olefin copolymer c-3 was prepared from propylene-ethylene copolymer (MFR (230°C, load 21.2 N, orifice diameter: 2 mm): 2.0 g / 10 min, density: 0.900 g / cm). 3 The content of ethylene units as α-olefin was 4.1 mol%.

[0101] [Example 1] <Production of Adhesive Polymer Composition> 15 parts by mass of a-1, 45 parts by mass of b-2, and 40 parts by mass of c-3 were dry blended and mixed, and the mixture was melt-kneaded using a twin-screw extruder (manufactured by The Japan Steel Works, Ltd., TEX25, D=25 mmφ, L / D=43) at a set temperature of 180 to 210°C, a screw rotation speed of 250 to 350 rpm, and an extrusion rate of 15 to 40 kg / h, and then strand cut to obtain a pellet-shaped adhesive polymer composition.

[0102] <Preparation of laminated film> The adhesive polymer composition in pellet form was charged into a monolayer T-die film molding machine manufactured by GSI Creos Co., Ltd., and molded at an extrusion molding temperature of 200 to 220° C. to a thickness of 100 μm to obtain a monolayer film. Using a heat seal testing machine manufactured by Sagawa Corporation, aluminum foil (25 μm) and the monolayer film (100 μm) obtained above were stacked together and thermally laminated at a temperature of 155°C for a compression time of 10 seconds to obtain a laminated film with an adhesive layer of 100 μm and a metal layer of 25 μm.

[0103] <Measurement of adhesive strength> The laminated film obtained above was cut into 10 mm wide strips to prepare test pieces, which were then held for 2 minutes at room temperature and in a thermostatic oven at temperatures ranging from 65°C to 105°C in 10°C increments, and then subjected to a peel test at a speed of 300 mm / min to measure the adhesive strength. The results are shown in Table 1.

[0104] [Examples 2 to 8, Comparative Examples 1 to 6] As shown in Table 1, components (A), (B), and (C) were melt-kneaded in the same manner as in Example 1 to obtain adhesive polymer compositions of Examples 2 to 8 and Comparative Examples 1 to 6, respectively.

[0105] Laminated films were produced from the adhesive polymer compositions of Examples 2 to 8 and Comparative Examples 1 to 6, respectively, in the same manner as in Example 1, and the adhesive strength was measured. The results are shown in Table 1.

[0106] [Table 1]

[0107] As can be seen from Table 1, the adhesive strength at high temperatures was significantly lower than the adhesive strength at room temperature in the adhesive polymer compositions of Examples 1 to 8. On the other hand, the adhesive polymer compositions of Comparative Examples 1 to 6 did not show a sufficient decrease in adhesive strength at high temperatures compared to the adhesive strength at room temperature. [Industrial Applicability]

[0108] The adhesive polymer composition according to this embodiment exhibits excellent adhesive strength properties to metal layers and polymer films, and therefore, a laminate according to this embodiment using this composition can be used for packaging various foods and beverages, pharmaceuticals and medical products, cosmetics, clothing, stationery, and other industrial materials, including batteries. Furthermore, the adhesive polymer composition according to this embodiment also exhibits a property in which the adhesive strength at high temperatures is significantly reduced compared to the adhesive strength at room temperature, and therefore, a laminate according to this embodiment using this composition can be particularly suitably used as an exterior material for lithium-ion batteries, where there is a concern that the exterior material may rupture due to an excessive increase in internal pressure.

Claims

1. The polymer component contains at least the following components (A) to (C): The adhesive polymer composition has a content of the component (B) of 30 to 77 parts by mass when the total content of the components (B) and (C) is 100 parts by mass. Component (A): Modified polypropylene obtained by grafting at least one unsaturated carboxylic acid or its derivative, or both, onto a propylene polymer. Component (B): an ethylene / α-olefin copolymer or a propylene / α-olefin copolymer having an α-olefin content of 5.8 mol % or more Component (C): Propylene homopolymer or propylene / α-olefin copolymer having an α-olefin content of less than 5.8 mol %

2. 2. The adhesive polymer composition according to claim 1, wherein the amount of maleic acid modification represented by the following formula (X) is 0.05 to 0.25% by mass: [Maleic Acid Modification Amount (% by Mass) of Adhesive Polymer Composition] = [Amount of maleic acid modification of component (A) (mass%)] × [Mass of component (A) (g)] / [Mass of polymer component (g)] Formula (X)

3. 2. The adhesive polymer composition according to claim 1, wherein the content of the component (A) is 1 to 30 parts by mass when the total content of the component (B) and the component (C) is 100 parts by mass.

4. A monolayer film comprising the adhesive polymer composition according to any one of claims 1 to 3.

5. A laminate comprising an adhesive layer containing the adhesive polymer composition according to any one of claims 1 to 3 and a substrate layer.

6. The laminate according to claim 5 , wherein the substrate layer is made of a metal material or a composite material of a metal and a polymer.

7. A method for producing a laminate, comprising a step of sandwiching the monolayer film according to claim 4 and a substrate between heated rolls and thermocompressing them.

8. The manufacturing method according to claim 7, wherein the substrate is made of a metal material or a composite material of a metal and a polymer.

9. A lithium ion battery exterior material comprising the laminate according to claim 6.

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