Adhesive resin composition and film

Abstract

The adhesive resin composition of the present invention contains 50 to 89.9 parts by mass of a propylene polymer (A) satisfying the following (a1) and (a2), 0.1 to 20 parts by mass of a modified polyolefin (B), and 10 to 30 parts by mass of an ethylene polymer (C) satisfying the following (c1) to (c3) (total of (A) to (C) is 100 parts by mass). (a1) contains a propylene polymer (a-1) having a melting point of ≥ 120°C and a propylene polymer (a-2) having a melting point of < 120°C. (a2) the proportion of (a-1) in (A) is 50 to 70.0 mass%. (c1) contains an ethylene homopolymer (c-1) and an ethylene-α-olefin copolymer (c-2). (c2) MFR = 0.1 to 10 g / 10 minutes. (c3) the proportion of (c-1) in (C) is 40 to 100 mass%.

Description

Technical Field

[0001] This invention relates to adhesive resin compositions and films using the adhesive resin compositions. Background Technology

[0002] In recent years, the application of lithium-ion batteries has gradually expanded to portable electronic devices, automobiles, and other fields. Unlike the metal cans used in the past, lithium-ion battery packaging materials utilize laminated packaging materials—composite materials in which a resin film is layered onto lightweight aluminum foil to create a bag-like shape—in order to accommodate the greater freedom in battery shape and miniaturization.

[0003] In addition, in lithium-ion batteries, the metal foils are bonded together by heat-sealing the ends of the metal foils with an adhesive polyolefin film, thus ensuring insulation.

[0004] Patent Document 1 describes a battery packaging material comprising, in sequence, at least a substrate layer, a metal foil layer having a chemically treated surface layer on at least one side, an acid-modified polyolefin layer, and a heat-sealing layer composed of a high-melting-point polypropylene layer and an ethylene-propylene random copolymer layer, wherein the high-melting-point polypropylene layer is disposed on the side closer to the metal foil layer than the ethylene-propylene random copolymer layer, and has a melting point of 150°C or higher.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2007-273398 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] The packaging film for lithium-ion batteries has a problem where the adhesive strength between the adhesive polyolefin film and the metal foil decreases when immersed in electrolyte. It is necessary to maintain this adhesive strength (hereinafter referred to as "electrolyte resistance"). However, the electrolyte resistance is insufficient when using the packaging film for batteries described in Patent Document 1.

[0010] In addition, lithium-ion batteries have an adhesive polyolefin film, known as an electrode sealing material, which bonds the electrodes together. This adhesive polyolefin film also needs to be resistant to electrolytes.

[0011] The purpose of this invention is to provide an adhesive resin composition capable of forming battery packaging films and lithium-ion battery electrode sealing materials with excellent electrolyte resistance, as well as a single-layer or multi-layer film that exhibits excellent electrolyte resistance when used in battery packaging films and lithium-ion battery electrode sealing materials.

[0012] Technical solutions for solving technical problems

[0013] This invention relates, for example, to the following [1] to

[11] .

[0014] [1] An adhesive resin composition comprising:

[0015] 50 to 89.9 parts by weight of propylene polymer (A) that meets the following (a1) and (a2);

[0016] 0.1–20 parts by mass of modified polyolefin (B) obtained by modifying polyolefin (b) with unsaturated carboxylic acids and / or their derivatives; and

[0017] 10 to 30 parts by mass of ethylene polymer (C) that satisfies (c1) to (c3) below (wherein, the total of (A), (B) and (C) is taken as 100 parts by mass).

[0018] (a1) contains propylene polymers with a melting point (Tm) above 120°C as observed in differential scanning calorimetry (a-1) and propylene polymers with a melting point (Tm) below 120°C or whose melting point is not observed (a-2).

[0019] (a2) The proportion of the above-mentioned propylene polymer (a-1) in the above-mentioned propylene polymer (A) is 50 to 70.0% by mass.

[0020] (c1) A copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms (c-1), and optionally an ethylene homopolymer (c-2).

[0021] (c2) The melt flow rate, measured according to ASTM D1238 at 190°C and 2.16 kg load, is 0.1 to 10 g / 10 minutes.

[0022] (c3) The copolymer (c-1) accounts for 40 to 100% of the total mass of the ethylene polymer (C).

[0023] [2] The adhesive resin composition as described in [1] above, wherein the content of the ethylene polymer (C) is 12.5 to 30 parts by weight.

[0024] [3] The adhesive resin composition as described in [1] or [2] above, wherein the melt flow rate (MFR) of the copolymer (c-1) as measured according to ASTM D1238 at 230°C and 2.16 kg load is less than 6.0 g / 10 min.

[0025] [4] The adhesive resin composition as described in any one of [1] to [3] above, wherein the polyolefin (B) contains 0.01 to 5% by mass of structures derived from the unsaturated carboxylic acid and / or its derivatives, converted to structures derived from maleic anhydride, and the polyolefin (b) contains 90 to 100 mol% of structural units derived from propylene.

[0026] [5] The adhesive resin composition as described in any one of [1] to [4] above, wherein the melt flow rate, as measured according to ASTM D1238 at 230°C and 2.16 kg load, is less than 7.0 g / 10 min.

[0027] [6] A single-layer or multi-layer film comprising at least one layer containing the adhesive resin composition described in any one of [1] to [5] above.

[0028] [7] A multilayer film comprising at least one layer containing the adhesive resin composition described in any one of [1] to [5] above, and at least one other layer other than the layer containing the adhesive resin composition, wherein the layer containing the adhesive resin composition is in contact with the other layers.

[0029] [8] A multilayer film comprising at least one layer containing the adhesive resin composition described in any one of [1] to [5] above, and at least one layer selected from the metal layer, the polyolefin layer and the polar resin layer, wherein the layer containing the adhesive resin composition is in contact with the layer selected from the metal layer, the polyolefin layer and the polar resin layer.

[0030] [9] A single-layer or multi-layer film as described in any one of [6] to [8] above, which is a film for battery packaging.

[0031]

[10] A single-layer or multi-layer film as described in any one of [6] to [8] above, which is an electrode sealing material for lithium-ion batteries.

[0032]

[11] A method for manufacturing a single-layer or multi-layer film, comprising a step of melt extruding the adhesive resin composition described in any one of [1] to [5] above.

[0033] The effects of the invention

[0034] According to the adhesive resin composition of the present invention, it is possible to form battery packaging films and electrode sealing materials for lithium-ion batteries with excellent electrolyte resistance.

[0035] The single-layer or multi-layer films involved in this invention exhibit excellent electrolyte resistance when used in battery packaging films and electrode sealing materials for lithium-ion batteries. Detailed Implementation

[0036] The present invention will now be described in more detail.

[0037] [Adhesive Resin Composition]

[0038] The adhesive resin composition involved in this invention contains a propylene polymer (A), a modified polyolefin (B), and an ethylene polymer (C).

[0039] <Propylene Polymer (A)>

[0040] The aforementioned propylene polymer (A) is a propylene polymer that satisfies conditions (a1) and (a2) described below.

[0041] Condition (a1) is that the above-mentioned propylene polymer (A) contains propylene polymers (a-1) with a melting point (Tm) of 120°C or higher as observed in differential scanning calorimetry, and propylene polymers (a-2) with a melting point (Tm) of less than 120°C or whose melting point is not observed.

[0042] (propylene polymer (a-1))

[0043] Examples of the aforementioned propylene-based polymers (a-1) include propylene homopolymers and copolymers of propylene with at least one α-olefin other than propylene having 2 to 20 carbon atoms. Among these, examples of α-olefins other than propylene having 2 to 20 carbon atoms include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene, with ethylene or α-olefins having 4 to 10 carbon atoms being preferred.

[0044] The copolymers of propylene and these α-olefins can be random copolymers or block copolymers. The structural units derived from these α-olefins may be present in the copolymer of α-olefins and propylene at a proportion of 35 mol% or less, preferably 30 mol% or less, more preferably 10 mol% or less, and even more preferably 5 mol% or less. Furthermore, the structural units may be present in the copolymer of α-olefins and propylene at a proportion of 1 mol% or more, more preferably 2 mol% or more.

[0045] The melting point (Tm) of the above-mentioned propylene polymer (a-1) was observed to be above 120°C in differential scanning calorimetry under the following conditions.

[0046] The melting point (Tm) is preferably 120–170°C, and more preferably 130–165°C.

[0047] (Measurement conditions)

[0048] The melting point (Tm) was determined using a differential scanning calorimeter (DSC) (e.g., a PerkinElmer DSC8500). Approximately 5 mg of sample was sealed in an aluminum dish to prepare the sample. The temperature profile was obtained by heating from room temperature to 230°C at a rate of 10°C / min, holding at 230°C for 10 minutes, then cooling to 30°C at a rate of 10°C / min, holding at 30°C for 1 minute, and then heating back to 230°C at a rate of 10°C / min. The peak temperature at the second heating (or the highest peak temperature in the case of multiple peak temperatures) was taken as the melting point (Tm).

[0049] The aforementioned propylene polymer (a-1) can be either isotactic or synisotactic.

[0050] That is, as forms of the aforementioned propylene polymer (a-1), isotactic propylene polymer (a-11) and syndiotactic propylene polymer (a-12) can be listed.

[0051] Examples of isotactic propylene polymers (a-11) include: homopolymers with excellent heat resistance, such as known homopolymers with a copolymer content other than propylene of 3 mol% or less; block polypropylenes with an excellent balance between heat resistance and flexibility, such as known block polypropylenes with a rubber component of 3 to 30 wt% n-decane dissolution; and atactic polypropylenes with an excellent balance between flexibility and transparency, such as known atactic polypropylenes with a melting peak of 120°C or higher, preferably in the range of 130°C to 150°C, as measured by differential scanning calorimetry (DSC). To obtain the desired physical properties, appropriate selections can be made from these, or two or more of the above-mentioned polypropylene components with different melting points or rigidities can be used together.

[0052] Such isotactic propylene polymers (a-11) can be manufactured, for example, by polymerizing propylene or copolymerizing propylene with other α-olefins in a Ziegler catalyst system consisting of a solid catalyst component containing magnesium, titanium, halogens and electron donors as essential components, and an organoaluminum compound and electron donors, or in a metallocene catalyst system using a metallocene compound as one component of the catalyst.

[0053] The isotactic propylene polymer (a-12) comprises 90 mol% or more of structural units derived from propylene and 10 mol% or less of one or more structural units derived from ethylene and α-olefins having 4 to 20 carbon atoms, preferably comprising 91 mol% or more of structural units derived from propylene and 9 mol% or less of one or more structural units derived from ethylene and α-olefins having 4 to 20 carbon atoms (wherein the total of the two structural units is taken as 100 mol%).

[0054] Examples of α-olefins with 4 to 20 carbon atoms include 1-butene, 3-methyl-1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

[0055] The isotactic propylene polymer (a-12) can be manufactured, for example, by the method described in International Publication No. WO2011 / 078054.

[0056] (propylene polymers (a-2))

[0057] The aforementioned propylene polymer (a-2) is a propylene polymer whose melting point (Tm) is below 120°C as observed in differential scanning calorimetry under the above conditions, or whose melting point cannot be observed in differential scanning calorimetry.

[0058] The aforementioned propylene-based polymer (a-2) has structural units derived from propylene and structural units derived from at least one olefin selected from α-olefins with 2 to 20 carbon atoms other than propylene. The content of the structural units derived from at least one α-olefin selected from 2 to 20 carbon atoms other than propylene is generally 30 mol% or less, preferably 5 to 30 mol%, more preferably 7 to 26 mol%, and even more preferably 10 to 20 mol%. The content of the structural units derived from propylene is preferably 74 to 93 mol%, more preferably 80 to 90 mol%.

[0059] The passage of the above-mentioned propylene polymer (a-2) 13 The isotactic ternary component percentage (mm fraction) measured by C-NMR is typically 80% or more, preferably 85% or more. A isotactic ternary component percentage (mm) within the above range is preferred in terms of maintaining mechanical properties.

[0060] Examples of α-olefins other than propylene with 2 to 20 carbon atoms include ethylene, 3-methyl-1-butene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are particularly preferred as at least one olefin selected from α-olefins other than propylene with 2 to 20 carbon atoms.

[0061] (Other conditions)

[0062] The intrinsic viscosity [η] of the propylene copolymer (a-2) measured in decahydronaphthalene at 135°C is preferably 0.1 to 10 dL / g, and more preferably 0.5 to 10 dL / g. The crystallinity of the propylene copolymer (a-2) as measured by X-ray diffraction is preferably 20% or less, and more preferably 0 to 15%.

[0063] The propylene copolymer (a-2) has a single glass transition temperature, which, when measured by differential scanning calorimetry (DSC), is typically in the range of -50°C to 10°C, preferably -40°C to 0°C, and more preferably -35°C to 0°C.

[0064] Furthermore, the molecular weight distribution (Mw / Mn, polystyrene conversion, Mw: weight-average molecular weight, Mn: number-average molecular weight) of the propylene copolymer (a-2) as measured by GPC is preferably 3.5 or less, more preferably 3.0 or less, and even more preferably 2.5 or less. Additionally, the lower limit is, for example, 1.5 or more.

[0065] Condition (a2) is that the proportion of the above-mentioned propylene polymer (a-1) in the above-mentioned propylene polymer (A) is 50 to 70.0% by mass. If the proportion of polymer (a-1) is within the above range, a composition with excellent whitening resistance can be obtained.

[0066] The melt flow rate (MFR) of the aforementioned propylene polymer (A), measured according to ASTM D1238 at 230°C and a load of 2.16 kg, is preferably in the range of 0.01 to 1000 g / 10 min, and more preferably 0.05 to 100 g / 10 min.

[0067] <Modified Polyolefin (B)>

[0068] The modified polyolefin (B) described above is obtained by modifying polyolefin (b) with unsaturated carboxylic acids and / or their derivatives.

[0069] As the polyolefin (b) mentioned above, polypropylene (b1) is preferably listed.

[0070] Polypropylene (b1) is, for example, a homopolymer of propylene and / or a propylene-α-olefin copolymer. The α-olefin is not limited, but ethylene and α-olefins having 4 to 20 carbon atoms are preferred; these α-olefins can be a single type or two or more types. Preferred α-olefins are ethylene and α-olefins having 4 to 10 carbon atoms, with ethylene and α-olefins having 4 to 8 carbon atoms being particularly suitable. The content of propylene-derived structural units in the propylene-α-olefin copolymer is at least 50 mol% and less than 100%.

[0071] The intrinsic viscosity [η] of polypropylene (b1) is preferably 0.1 to 10 dl / g. If the intrinsic viscosity [η] is within this range, a composition with excellent moldability and mechanical strength can be obtained.

[0072] There are no particular limitations on the manufacturing method of polypropylene (b1), and known methods using known catalysts such as Ziegler-Natta catalysts and metallocene catalysts can be cited.

[0073] As polypropylene (b1), a crystalline polymer is preferred; in the case of a copolymer, it can be a random copolymer or a block copolymer. Polypropylene (b1) can be a commercially available product.

[0074] Polypropylene (b1) is, for example, homopolymer polypropylene or a random copolymer of propylene and α-olefin. Alternatively, it may contain several different isotactic polypropylenes.

[0075] Examples of unsaturated carboxylic acids and / or their derivatives include unsaturated compounds having one or more carboxyl groups in one molecule, esters of compounds having carboxyl groups and alkyl alcohols, and unsaturated compounds having one or more structures represented by R-CO-O-CO-R′ (where R and R′ are each independently a hydrocarbon group) in one molecule. Examples of unsaturated groups in unsaturated compounds include vinyl groups, vinylidene groups, and unsaturated cyclic hydrocarbon groups. Unsaturated carboxylic acids and / or their derivatives may be used alone or in combination of two or more. Among these, unsaturated dicarboxylic acids and their anhydrides are preferred, and maleic acid, norbornyl edodecanic acid, and their anhydrides are particularly preferred.

[0076] The amount of structures derived from unsaturated carboxylic acids and / or their derivatives in the modified polyolefin (B) described above, converted to the amount of structures derived from maleic anhydride (i.e., assuming the unsaturated carboxylic acids and / or their derivatives are maleic anhydride), is preferably 0.01 to 5% by mass, more preferably 0.05 to 3.5% by mass. If the amount of structures derived from unsaturated carboxylic acids and / or their derivatives is within the above range, a resin composition with a good balance between moldability and adhesion can be obtained.

[0077] In the modified polyolefin (B) described above, the polyolefin (b) preferably contains 50 to 100 mol% of propylene-derived structural units. If the content of propylene-derived structural units is within the above range, a resin composition with excellent heat resistance can be obtained.

[0078] There are no particular limitations on the method for modifying the above-mentioned polyolefin (b) with unsaturated carboxylic acids and / or their derivatives, and existing known graft polymerization methods such as solution polymerization and melt mixing can be used. For example, methods include: melting the above-mentioned polyolefin (b) and adding unsaturated carboxylic acids and / or their derivatives thereto to cause a grafting reaction; or dissolving the above-mentioned polyolefin (b) in a solvent to prepare a solution and adding unsaturated carboxylic acids and / or their derivatives thereto to cause a grafting reaction, etc.

[0079] <Ethylene-based polymers (C)>

[0080] The ethylene polymer (C) mentioned above is an ethylene polymer that satisfies the following conditions (c1) to (c3).

[0081] Condition (c1) is that the above-mentioned ethylene polymer (C) contains a copolymer (c-1) of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms, and optionally an ethylene homopolymer (c-2).

[0082] Examples of the aforementioned α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene, among which propylene, 1-butene, 1-hexene, and 1-pentene are preferred.

[0083] The above-mentioned α-olefins can be one type or two or more types.

[0084] The copolymer (c-1) preferably contains 30 to 99 mol% of structural units derived from ethylene, preferably 50 to 99 mol%, and 1 to 70 mol% of structural units derived from α-olefins selected from α-olefins with 3 to 20 carbon atoms, preferably 1 to 50 mol% (wherein the total of the two is taken as 100 mol%).

[0085] In addition, the melt flow rate (MFR) of the above copolymer (c-1) measured according to ASTM D1238 at 230°C and 2.16 kg load is preferably less than 6.0 g / 10 min, more preferably 0.5 to 5.5 g / 10 min, and even more preferably 0.5 to 2.0 g / 10 min.

[0086] Furthermore, the melt flow rate (MFR) of the copolymer (c-1) measured according to ASTM D1238 at 190°C and 2.16 kg load is preferably less than 4.5 g / 10 min, more preferably 0.3 to 4.1 g / 10 min, and even more preferably 0.3 to 1.5 g / 10 min.

[0087] Condition (c2) is that the melt flow rate (MFR) of the above-mentioned vinyl polymer (C) is 0.1 to 10 g / 10 min, as measured according to ASTM D1238 at 190°C and 2.16 kg load.

[0088] The MFR is preferably 0.3 to 8 g / 10 minutes, more preferably 0.5 to 6 g / 10 minutes. If the MFR is within the above range, the composition of the present invention has a good and excellent balance between softness and mechanical strength, and has high adhesive force.

[0089] On the other hand, if the MFR exceeds 10 g / 10 min, the thickness reduction of the composition during heat sealing increases, the adhesive layer formed by the composition becomes thinner, and thus its adhesive strength decreases. If the MFR is less than 0.1 g / 10 min, the wettability to the adherend decreases, and thus the adhesive strength decreases.

[0090] From the viewpoint of flexibility, the density of the aforementioned vinyl polymer (C) is preferably between 0.855 and 0.970 g / cm³. 3 More preferably 0.860~0.940g / cm³ 3 Further optimization is needed, with a concentration of 0.865–0.930 g / cm³. 3 The range.

[0091] Condition (c3) is that the proportion of the above copolymer (c-1) in the above ethylene polymer (C) is 40 to 100% by mass. From the viewpoint of electrolyte resistance, the above proportion is preferably 45 to 100% by mass, and more preferably 50 to 100% by mass.

[0092] There are no particular limitations on the manufacturing method of the copolymer (c-1) and homopolymer (c-2) described above. They can be manufactured using a high-pressure process or a known method using known catalysts such as Ziegler-Natta catalysts or metallocene catalysts. The copolymer (c-1) and homopolymer (c-2) described above can also be commercially available products.

[0093] Vinyl polymers (C) can also be polymers grafted with a small amount of maleic anhydride, provided that the above conditions are met. In addition, provided that the above conditions are met, the grafted monomer can be further modified with diamines, carbodiimides, etc. after grafting with a small amount of maleic anhydride, etc.

[0094] <Any ingredient>

[0095] The adhesive resin composition of the present invention may contain additives without impairing the effects of the present invention. Examples of additives include antioxidants, ultraviolet absorbers, neutralizers, nucleating agents, light stabilizers, antistatic agents, anti-blocking agents, lubricants, odor absorbers, antibacterial agents, hygroscopic agents, pigments, inorganic or organic fillers, and polymers other than propylene polymers (A), modified polyolefins (B), and ethylene polymers (C).

[0096] (Adhesive resin composition)

[0097] Regarding the content of propylene polymer (A), modified polyolefin (B), and ethylene polymer (C) in the adhesive resin composition of the present invention, the total content of these three components is taken as 100 parts by mass, which is 50-89.9 parts by mass, 0.1-20 parts by mass, and 10-30 parts by mass, respectively. Preferably, it is 50-87.5 parts by mass, 0.5-20 parts by mass, and 12-30 parts by mass, respectively. More preferably, it is 50-84 parts by mass, 1-20 parts by mass, and 15-30 parts by mass, respectively.

[0098] If the content of the above-mentioned components is within the above-mentioned range, the resin composition of the present invention has high adhesiveness, especially after electrolyte impregnation, and the film containing the layer obtained by the composition of the present invention is not prone to a decrease in adhesiveness due to impregnation in the electrolyte.

[0099] If the content of the propylene polymer (A) is less than 50 parts by weight, the desired initial adhesion cannot be obtained.

[0100] A content of 12.5 to 30 parts by weight or 13 to 30 parts by weight of vinyl polymer (C) is also preferred. If the content of vinyl polymer (C) is within the above range, the adhesiveness of the adhesive resin composition is less likely to decrease due to impregnation in the electrolyte, and the stability during film formation is excellent.

[0101] The MFR (Mean Factor Friction) of the adhesive resin composition of the present invention (according to ASTM D1238, at 190°C and 2.16 kg load) is preferably less than 7.0 g / 10 min, more preferably more than 3.0 g / 10 min and less than 7.0 g / 10 min. If the MFR is within the above range, the adhesive resin composition of the present invention has a good and excellent balance between moldability (resistance to thickness reduction) and adhesion.

[0102] The amount of the structure derived from the above-mentioned unsaturated carboxylic acid and / or its derivatives in the adhesive resin composition of the present invention, converted into the amount of the structure derived from maleic anhydride (i.e., assuming that the unsaturated carboxylic acid and / or its derivatives are maleic anhydride), is preferably 0.03 to 0.30% by mass, more preferably 0.06 to 0.20% by mass.

[0103] The adhesive resin composition of the present invention can be manufactured by conventionally known methods, except that the above-mentioned propylene polymer (A), modified polyolefin (B), and ethylene polymer (C) are used as raw materials. For example, it can be manufactured by melt-blending the above-mentioned components.

[0104] <Island Structure>

[0105] The adhesive resin composition of the present invention forms a finely dispersed structure (so-called island structure) containing the aforementioned propylene polymer (A) in a continuous phase and the aforementioned ethylene copolymer (C) dispersed in the aforementioned continuous phase in a dispersed phase. By forming such a structure, the electrolyte resistance of the layer containing the adhesive resin composition is improved. The reason for this is not yet certain, but it can be speculated that it is because the electrolyte is trapped by the dispersed phase, thereby preventing the electrolyte from penetrating to the interface between the layer containing the adhesive resin composition and the metal (hereinafter also referred to as the "adhesive interface").

[0106] The average particle size of the dispersed phase, as measured by the following method, is preferably 0.001 to 10 μm. The upper limit of the average particle size of the dispersed phase is more preferably 8 μm, further preferably 6 μm, particularly preferably 5 μm, and the lower limit is preferably 0.09 μm.

[0107] (Method for determining average particle size)

[0108] The test specimens were ground using a microtome or similar equipment. Then, arbitrary cross-sections of approximately 45 μm × 75 μm or larger were magnified up to 3000 times and analyzed using a transmission electron microscope (e.g., Hitachi High Technology H-7650). The analysis was performed using image processing software (e.g., ImageJ) for binarization.

[0109] The occupied areas of the continuous phase and the dispersed phase were determined based on the TEM images.

[0110] When the dispersed phase is circular, the diameter is used as the particle size; when the dispersed phase is elliptical, the length of the major axis is used as the particle size. Furthermore, for shapes other than circular or elliptical, the area of ​​the dispersed phase is calculated, and the diameter of a circle with an area equal to that area is determined and used as the particle size.

[0111] If the average particle size of the dispersed phase is above 0.001 μm, sufficient cavitation effect can be obtained, and good resistance to electrolyte can be achieved.

[0112] If the average particle size of the dispersed phase is less than 10 μm, the presence of the dispersed phase at the bonding interface will not hinder the adhesion of the continuous phase, and the composition of the present invention can exhibit good adhesion.

[0113] In a randomly selected 10μm × 10μm region of the cross section of the test piece used to determine the average particle size of the dispersed phase in the adhesive resin composition of the present invention, the proportion of dispersed phase with a particle size of 0.001 to 5μm that accounts for more than 80% of the total dispersed phase is preferably 80% or more, more preferably 85% or more, further preferably 90% or more, particularly preferably 95% or more, and most preferably 100%. If the above proportion is 80% or more, the adhesive properties of the composition are excellent.

[0114] [Single-layer or multi-layer film]

[0115] The single-layer or multi-layer film of the present invention is characterized in that it comprises at least one layer containing the adhesive resin composition of the present invention described above.

[0116] Examples of specific embodiments of the single-layer or multi-layer film of the present invention can be listed as follows:

[0117] A multilayer film comprising at least one layer containing the adhesive resin composition of the present invention, and at least one other layer besides the layer containing the adhesive resin composition, wherein the layer containing the adhesive resin composition is in contact with the other layers; and

[0118] A multilayer film comprising at least one layer containing the adhesive resin composition of the present invention, and at least one layer selected from the metal layer, polyolefin layer and polar resin layer, wherein the layer containing the adhesive resin composition is in contact with the layer selected from the metal layer, polyolefin layer and polar resin layer.

[0119] Other layers mentioned above may include metal layers, polyolefin layers, and polar resin layers.

[0120] Examples of metal-containing layers mentioned above include aluminum layers (e.g., aluminum foil), copper layers, and stainless steel layers.

[0121] Examples of the aforementioned polyolefin layers include polypropylene layers, poly4-methylpentene layers, and polyethylene layers.

[0122] Examples of polar resin layers include polyamide layers, EVOH layers, PET layers, and PBT layers.

[0123] Layers containing the adhesive resin composition of the present invention can be manufactured by molding the adhesive resin composition of the present invention, for example, by melt extrusion molding. Therefore, single-layer or multi-layer films of the present invention can be manufactured by casting, blow molding, extrusion lamination, etc.

[0124] The single-layer or multi-layer film of the present invention is preferably used as a battery packaging film such as a lithium battery packaging film, or as an electrode sealing material for lithium-ion batteries.

[0125] Example

[0126] The present invention will now be described in more detail based on embodiments, etc., but the present invention is not limited to these embodiments in any way.

[0127] [Methods for determining physical properties]

[0128] <Mel Flow Rate (MFR)>

[0129] The MFR of propylene polymers and compositions was determined according to ASTM D1238 at a temperature of 230°C and a load of 2.16 kg.

[0130] The MFR of vinyl polymers is determined according to ASTM D1238 at a temperature of 190°C and a load of 2.16 kg or at a temperature of 230°C and a load of 2.16 kg. When the vinyl polymer contains two or more copolymers (c-1) and ethylene homopolymers (c-2), the "MFR of vinyl polymer" refers to the value calculated from the MFRs of each vinyl polymer using the logarithmic addition rule.

[0131] <Density>

[0132] Density was determined according to JIS K7112 (density gradient tube method).

[0133] <Proportion of structural units>

[0134] The quantitative determination of the proportion of ethylene or propylene-derived structural units in a polymer by means of... 13 C-NMR is performed using the following apparatus and conditions.

[0135] A JECX400P nuclear magnetic resonance (NMR) instrument manufactured by NJE Ltd was used under the following conditions: a mixed solvent of deuterated o-dichlorobenzene / deuterated benzene (80 / 20 volume %) was used; the sample concentration was 60 mg / 0.6 mL; the measurement temperature was 120 °C; and the observed nuclei were... 13 C (100MHz), the sequence is a single-pulse proton decoupled sequence with a pulse width of 4.62μs (45° pulse), a repetition time of 5.5 seconds, and a cumulative count of 8000 times. 29.73ppm is used as the reference value for chemical shift.

[0136] <Grafting Modification Quantity>

[0137] The amount of structure derived from maleic anhydride (grafted modification amount) was determined using an infrared absorption analyzer at 1790 cm⁻¹. －1 The intensity of the peak was quantified using a pre-prepared standard curve.

[0138] [raw material]

[0139] The polyolefins used in the examples and comparative examples are represented below. These polyolefins were all polymerized according to conventional methods and optionally grafted with maleic anhydride.

[0140] Propylene polymers (A)

[0141] • PP-1: Random polypropylene (propylene content 96 mol%, ethylene content 4 mol%, MFR = 7.0 g / 10 min, density = 0.91 g / cm³) 3 Melting point = 138℃, isotactic structure)

[0142] • PP-2: Random polypropylene (propylene content 96 mol%, ethylene content 4 mol%, MFR = 29.0 g / 10 min, density = 0.90 g / cm³) 3 Melting point = 138℃, isotactic structure)

[0143] • PER-1: Propylene-ethylene copolymer (propylene content 87 mol%, ethylene content 13 mol%, MFR = 8.0 g / 10 min, density = 0.88 g / cm³) 3 Melting point = 79℃

[0144] Polyolefin (B)

[0145] • Modified PP-1: Modified homopolymer polypropylene (the amount of structure derived from maleic anhydride (graft modification amount) 3.0% by mass)

[0146] Vinyl polymers (C)

[0147] • EPR-1: Ethylene-propylene copolymer (ethylene content 80 mol%, propylene content 20 mol%, temperature 190℃, MFR at 2.16 kg load = 0.6 g / 10 min; temperature 230℃, MFR at 2.16 kg load = 0.8 g / 10 min, density = 0.87 g / cm³) 3 )

[0148] • PE-1: Low-density polyethylene (MFR = 7.0 g / 10 min at 190°C and 2.16 kg load, MFR = 17.8 g / 10 min at 230°C and 2.16 kg load, density = 0.91 g / cm³) 3 )

[0149] [Example 1]

[0150] <Preparation of Composition 1>

[0151] Composition 1 was obtained by melt-blending 48 parts by weight of PP-1, 25 parts by weight of PER-1, 5 parts by weight of modified PP-1, 15 parts by weight of EPR-1 and 7 parts by weight of PE-1 at 230°C using a single screw extruder.

[0152] <Manufacturing of Composites>

[0153] A 100 μm thick film was formed from composition 1 obtained in Example 1 using an extruder with a T-die. The resulting film was overlapped with a 200 μm thick aluminum foil and heat-sealed for 5 seconds at 160°C and 0.1 MPa. The resulting composite was cut into 15 mm wide pieces as samples for testing.

[0154] <Electrolyte impregnation of the complex>

[0155] One sample for determination was immersed in an electrolyte containing 1 mol / L LiPF6, with ethyl carbonate: diethyl carbonate = 3:7 and 1000 ppm water added, and allowed to stand at 85°C for 1 week.

[0156] <Determination of the adhesive strength of composites>

[0157] For the other test samples (freshly manufactured composites) and the test samples after electrolyte impregnation (electrolyte-impregnated composites), the adhesion strength (unit: N / 15 mm) between the aluminum foil and the film formed from composition 1 was measured using a tensile testing machine and the T-peel method at room temperature (23°C). The crosshead speed was set to 300 mm / min. Scores were given and recorded in Table 1 based on the ratio of the adhesion strength of the electrolyte-impregnated composite (hereinafter also referred to as "adhesion strength after electrolyte impregnation") to the adhesion strength of the freshly manufactured composite (hereinafter also referred to as "initial adhesion strength"). The evaluation criteria are as follows.

[0158] (Initial adhesion)

[0159] CC: Less than 8N / 15mm

[0160] BB: 8N / 15mm or higher but less than 10N / 15mm

[0161] AA: 10N / 15mm or more

[0162] (Electrolyte resistance)

[0163] CC: Adhesion strength after electrolyte impregnation / initial adhesion strength less than 10%.

[0164] BB: The adhesion strength after electrolyte impregnation / initial adhesion strength is 10% or more but less than 15%.

[0165] AA: Adhesion strength after electrolyte impregnation / initial adhesion strength is 15% or more.

[0166] In addition, "-" indicates that electrolyte resistance was not evaluated.

[0167] <Evaluation of the wall thinning properties of the composition>

[0168] A 100 μm thick film was formed from composition 1 obtained in Example 1 using an extrusion molding machine with a T-die. Two films were overlapped and heat-sealed for 3 seconds at 170°C and 0.2 MPa. The cross-section of the heat-sealed portion was observed under a microscope, and the thickness of the thinnest part was measured as the heat-sealed thickness. The residual rate after heat sealing was calculated as (heat-sealed thickness) / (initial thickness of the two films). Based on the residual rate, a score was given and recorded in Table 1. The evaluation criteria are as follows.

[0169] (Thickness reduction resistance)

[0170] CC: Thickness after heat sealing / initial thickness less than 30%.

[0171] BB: The thickness after heat sealing / initial thickness is 30% or more but less than 60%.

[0172] AA: The thickness after heat sealing / initial thickness is 60% or more.

[0173] <Evaluation of the whitening resistance of the composition>

[0174] PP-2 and Composition 1 were co-extruded at 290°C using a screw with a diameter of 50 mm and an effective length L / D = 28. The extruded PP-2 and Composition 1 were then laminated within a feed block with PP-2 as the outer layer and Composition 1 as the inner layer, creating a film-like laminate with both outer and inner layers being 20 μm thick and approximately 40 μm thick. The die temperature was 290°C. This laminate was brought into contact with the surface of an aluminum foil (20 μm thick) in a molten state, and then pulled at a speed of 50 m / min while being cooled using a cooling roller with pinch rollers. The resulting multilayer film was deep-drawn using a die with a 5 mm engagement depth. The degree of whitening on the wall surface of the resulting molded body was evaluated visually according to the following criteria.

[0175] AA: No albinism

[0176] BB: Mild albinism

[0177] CC: Obvious whitening

[0178] [Examples 2 and 3, Comparative Examples 1 to 6]

[0179] Compositions were prepared according to the formulations shown in Table 1. Alternatively, compositions were prepared using the same method as in Example 1. The resulting compositions were used to manufacture composites, and the results were evaluated. The results are presented in Table 1.

[0180] [Table 1]

[0181]

Claims

1. An adhesive resin composition, characterized in that, contain: 50 to 89.9 parts by weight of propylene polymer (A) that meets the following (a1) and (a2); Modified polyolefin (B) obtained by modifying polyolefin (b) with unsaturated carboxylic acids and / or their derivatives, comprising 0.1 to 20 parts by mass, wherein the derivatives of unsaturated carboxylic acids refer to esters of compounds having carboxyl groups and alkyl alcohols, or unsaturated compounds having one or more structures represented by R-CO-O-CO-R′ in one molecule, wherein R and R′ are each independently a hydrocarbon group; and 10-30 parts by weight of ethylene-based polymer (C) satisfying (c1) to (c3) below, The total of (A), (B), and (C) is taken as 100 parts by weight. The melt flow rate of the adhesive resin composition, as measured according to ASTM D1238 at 230°C and a 2.16 kg load, is less than 7.0 g / 10 min. (a1) Contains propylene polymers with a melting point (Tm) above 120°C as observed in differential scanning calorimetry (a-1), and propylene polymers with a melting point (Tm) below 120°C or whose melting point is not observed (a-2). (a2) The propylene polymer (a-1) accounts for 50 to 70.0% by mass of the propylene polymer (A); (c1) Contains a copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms (c-1), and optionally an ethylene homopolymer (c-2). (c2) The melt flow rate, measured according to ASTM D1238 at 190°C and a load of 2.16 kg, is 0.1–10 g / 10 min; (c3) The copolymer (c-1) accounts for 40 to 100% by mass of the ethylene polymer (C).

2. The adhesive resin composition according to claim 1, characterized in that: The content of the ethylene polymer (C) is 12.5 to 30 parts by mass.

3. The adhesive resin composition according to claim 1 or 2, characterized in that: The melt flow rate (MFR) of the copolymer (c-1), as measured according to ASTM D1238 at 230°C and 2.16 kg load, is less than 6.0 g / 10 min.

4. The adhesive resin composition according to claim 1 or 2, characterized in that: The polyolefin (B) contains 0.01 to 5% by mass of a structure derived from the unsaturated carboxylic acid and / or its derivatives, converted to a structure derived from maleic anhydride. The polyolefin (b) contains 90-100 mol% of propylene-derived structural units.

5. A single-layer or multi-layer film, characterized in that: It comprises at least one layer containing the adhesive resin composition of claim 1 or 2.

6. A multilayer film, characterized in that: The material comprises at least one layer containing the adhesive resin composition of claim 1 or 2, and at least one other layer other than the layer containing the adhesive resin composition, wherein the layer containing the adhesive resin composition is in contact with the other layer.

7. A multilayer film, characterized in that: The material comprises at least one layer containing the adhesive resin composition of claim 1 or 2, and at least one layer selected from the metal-containing layer, the polyolefin layer, and the polar resin layer, wherein the layer containing the adhesive resin composition is in contact with the layer selected from the metal-containing layer, the polyolefin layer, and the polar resin layer.

8. The single-layer or multi-layer film as described in claim 5, characterized in that: It is a film used for battery packaging.

9. The single-layer or multi-layer film as described in claim 5, characterized in that: It is an electrode sealing material for lithium-ion batteries.

10. A method for manufacturing a single-layer or multi-layer film, characterized in that: The process includes the process of melt-extruding the adhesive resin composition according to claim 1 or 2.

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