Resin composition, film containing the same, and use thereof

Abstract

This invention relates to a resin composition wherein the content of a propylene polymer (A) satisfying specified conditions is 10 to 99.9 parts by mass, the content of a propylene polymer (B) satisfying specified conditions is 0 to 40 parts by mass, the content of a polyolefin (C) containing structural units derived from unsaturated carboxylic acids and / or their derivatives is 0.1 to 20 parts by mass, and the content of an ethylene polymer (D) satisfying specified conditions is 0 to 40 parts by mass (wherein, the total content of components (A), (B), (C) and (D) is set to 100 parts by mass).

Description

Technical Field

[0001] This invention relates to resin compositions, films containing the resin compositions, and their uses. Background Technology

[0002] Polypropylene has long been widely used as a thermoplastic molding material with excellent rigidity, heat resistance, and transparency. However, because polypropylene is a non-polar material, it exhibits poor adhesion to polar materials such as metals like aluminum and ethylene-vinyl alcohol copolymers. To improve adhesion, techniques for modifying polypropylene using unsaturated carboxylic acids or their derivatives are widely known. Furthermore, due to polypropylene's poor flexibility, it is typically combined with a soft rubber component when used as an adhesive resin. A polypropylene-based adhesive resin has been proposed that improves adhesion by combining a soft rubber component with polypropylene (Patent Document 1).

[0003] Furthermore, due to the high permeability of polypropylene, it is often laminated with polar resins such as ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA), and polyester (e.g., polyethylene terephthalate (PET)) to maintain the freshness of the contents and extend the shelf life when used as a food packaging material. This multilayer film is then processed into container shapes such as cups and trays through secondary processing such as deep drawing. For example, a multilayer film for deep drawing is proposed in Patent Document 2, etc.

[0004] Furthermore, polypropylene, due to its moderate flexibility, abrasion resistance, scratch resistance, heat resistance, chemical resistance, and post-processing properties, can also be used as a building or industrial material. Examples of building or industrial materials include decorative films that are bonded to the surface of wood-based panels, inorganic panels, metal sheets, etc., using adhesives, and used as decorative panels. Patent document 3, etc., discloses a technique for bonding a pattern layer on a substrate film constituting a decorative film to a polypropylene protective layer for protecting the pattern layer, separated by a polypropylene adhesive resin layer.

[0005] On the other hand, metal cans have traditionally been used in secondary batteries, such as lithium-ion batteries. However, in recent years, to meet the demands for thinner and more diverse products, a shift has occurred towards pouch-like laminated packaging materials made by laminating a resin film onto aluminum foil. For the extraction of electricity, metal lead substrates, such as aluminum or nickel, are installed on the metal substrates of the positive and negative electrodes of the lithium-ion battery. To prevent short circuits between the lead substrates and the aluminum foil of the laminated packaging material, and to improve the sealing strength between the lead substrates and the innermost resin layer (sealing layer) of the laminated packaging material, a film-like insulator (tab membrane) is typically sandwiched between the sealed portion of the lead substrates. Such tab membranes and other tab sealing materials have been proposed in patent documents such as 4-6.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 04-300933

[0009] Patent Document 2: Japanese Patent Application Publication No. 2000-301675

[0010] Patent Document 3: Japanese Patent No. 4803441

[0011] Patent Document 4: Japanese Patent Application Publication No. 2014-210841

[0012] Patent Document 5: Japanese Patent Application Publication No. 2014-225378

[0013] Patent Document 6: International Publication No. 2014-106887 Summary of the Invention

[0014] The technical problem that the invention aims to solve

[0015] In recent years, for adhesive films, there has been a demand for improving low-temperature adhesion, which allows for bonding with less heat, in order to increase productivity. Furthermore, for food packaging films used in the form of containers such as cups and trays, as well as building or industrial materials such as decorative films, and secondary battery components such as outer packaging materials for lithium-ion batteries, secondary processing such as deep drawing or bending is often performed. Therefore, it is also necessary to prevent whitening during secondary processing. However, existing technologies such as Patent Documents 2-6 are insufficient to meet this requirement.

[0016] The present invention addresses the aforementioned technical problems and aims to provide an adhesive resin composition capable of forming food packaging materials, building or industrial materials, and secondary battery components with excellent low-temperature adhesion and whitening prevention, a film containing the composition, and food packaging materials, building or industrial materials, and secondary battery components containing the film.

[0017] Technical solutions for solving technical problems

[0018] The inventors of this invention conducted research to solve the aforementioned technical problems. As a result, they discovered that the above-mentioned technical problems could be solved through the following methods, thus completing this invention.

[0019] [1] A resin composition wherein the content of an propylene polymer (A) satisfying (a) below is 10 to 99.9 parts by mass, the content of an propylene polymer (B) satisfying (b) below is 0 to 40 parts by mass, the content of a polyolefin (C) containing structural units derived from unsaturated carboxylic acids and / or their derivatives is 0.1 to 20 parts by mass, and the content of an ethylene polymer (D) satisfying (d) below is 0 to 40 parts by mass (wherein the total content of components (A), (B), (C) and (D) is set to 100 parts by mass).

[0020] (a) The melting point (Tm) observed in differential scanning calorimetry is above 100°C and below 120°C;

[0021] (b) The MFR measured according to ASTM D1238 at 230°C and 2.16 kg load is in the range of 0.01 to 100 g / 10 minutes, and meets the following conditions (b-1) and (b-2):

[0022] (b-1) The melting point (Tm) observed in differential scanning calorimetry is below 100°C or the melting point (Tm) cannot be observed.

[0023] (b-2) Contains structural units derived from propylene and structural units derived from at least one olefin selected from ethylene and α-olefins having 4 to 20 carbon atoms, wherein the content of structural units derived from ethylene and at least one α-olefin having 4 to 20 carbon atoms is less than 40 mol%.

[0024] (d) is an ethylene homopolymer or a copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms, with an MFR in the range of 0.1 to 10 g / 10 minutes as measured by ASTM D1238 at 190°C and a load of 2.16 kg.

[0025] [2] The resin composition as described in [1], wherein the content of the propylene polymer (A) is 10 to 94.9 parts by mass, the content of the propylene polymer (B) is 5 to 40 parts by mass, the content of the polyolefin (C) is 0.1 to 20 parts by mass, and the content of the ethylene polymer (D) is 0 to 40 parts by mass (wherein the total content of components (A), (B), (C) and (D) is set to 100 parts by mass).

[0026] [3] The resin composition as described in [1], wherein the content of the propylene polymer (A) is 10 to 94.9 parts by mass, the content of the propylene polymer (B) is 0 to 40 parts by mass, the content of the polyolefin (C) is 0.1 to 20 parts by mass, and the content of the ethylene polymer (D) is 5 to 40 parts by mass (wherein the total content of components (A), (B), (C) and (D) is set to 100 parts by mass).

[0027] [4] The resin composition as described in [3], wherein the density of the ethylene polymer (D) is 0.87 g / cm³. 3 the following.

[0028] [5] A single-layer or multi-layer film, wherein it comprises at least one layer containing the resin composition described in any one of [1] to [4].

[0029] [6] A multilayer film comprising at least one layer containing a resin composition as described in any one of [1] to [4], and at least two other layers besides the layer containing the above composition, wherein two sides of the layer containing the above composition are in contact with the other layers.

[0030] [7] A multilayer film comprising at least one layer containing a resin composition as described in any one of [1] to [4], and at least one layer selected from a metal layer, a polyolefin layer and a polar resin layer, wherein the layer containing the above composition is in contact with at least one of the metal layer, the polyolefin layer and the polar resin layer.

[0031] [8] A food packaging material comprising the single-layer or multi-layer film of [5], or the multi-layer film of [6] or [7].

[0032] [9] A building or industrial material comprising a single-layer or multi-layer film as described in [5], or a multi-layer film as described in [6] or [7].

[0033]

[10] A component for a secondary battery, comprising a single-layer or multi-layer film as described in [5], or a multi-layer film as described in [6] or [7].

[0034]

[11] The secondary battery component as described in

[10] , wherein the secondary battery component is an outer packaging material for lithium-ion batteries.

[0035]

[12] The secondary battery component as described in

[10] is a tab membrane for a lithium-ion battery.

[0036]

[13] A method for manufacturing a single-layer or multi-layer film, wherein the resin composition described in any one of [1] to [4] is melt-extruded into shape.

[0037] Invention Effects

[0038] According to the present invention, it is possible to provide an adhesive resin composition capable of forming food packaging materials, building or industrial materials, and secondary battery components with excellent low-temperature adhesion and whitening prevention, a film containing the composition, and food packaging materials, building or industrial materials, and secondary battery components containing the film. Detailed Implementation

[0039] In this specification, the numerical range indicated by “~” means the range including the values ​​recorded before and after “~” as the lower and upper limits.

[0040] The resin composition of the present invention may contain an propylene polymer (A) and a polyolefin (C) containing structural units derived from unsaturated carboxylic acids and / or their derivatives, and may also contain an propylene polymer (B) or an ethylene polymer (D), or contain an propylene polymer (B) and an ethylene polymer (D).

[0041] Propylene polymers (A)

[0042] Examples of propylene-based polymers (A) include propylene homopolymers and copolymers of propylene with at least one α-olefin having 2 to 20 carbon atoms other than propylene. Examples of α-olefins having 2 to 20 carbon atoms other than propylene 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.

[0043] The copolymers of propylene with these α-olefins can be random copolymers or block copolymers. The proportion of structural units from these α-olefins in the copolymer of α-olefins and propylene can be less than 35 mol%, preferably less than 30 mol%.

[0044] The propylene polymer (A) satisfies the following condition (a).

[0045] (a) The melting point (Tm) observed in differential scanning calorimetry is above 100°C and below 120°C. Because the melting point (Tm) is within the above range, the resin composition of the present invention exhibits excellent whitening resistance and excellent low-heat adhesion.

[0046] The melting point (Tm) is preferably 100-115°C, more preferably 100-110°C.

[0047] The propylene polymer (A) preferably has a melt flow rate (MFR) of 0.01 to 1000 g / 10 min, preferably 0.1 to 100 g / 10 min, as measured according to ASTM D1238 at 230°C and a load of 2.16 kg.

[0048] The aforementioned propylene polymer (A) can be any structure of isotactic or syndiotactic, and any structure can be selected as described later, taking into account compatibility with the propylene polymer (B).

[0049] That is, as forms of the aforementioned propylene polymer (A), isotactic propylene polymer (A1) and syndiotactic propylene polymer (A2) can be cited.

[0050] Examples of isotactic propylene polymers (A1) include homopolymer polypropylene with excellent heat resistance, such as known homopolymer polypropylene with a copolymer content other than propylene typically below 3 mol%; block polypropylene with excellent balance between heat resistance and flexibility, such as known block polypropylene typically containing 3 to 30 wt% n-decane-eluting rubber components; and atactic polypropylene with excellent balance between flexibility and transparency, such as known atactic polypropylene whose melting peak measured by differential scanning calorimetry (DSC) is typically in the range of 100°C or higher and below 120°C, preferably in the range of 100 to 110°C. To obtain the desired physical properties, appropriate selection can be made from these, or two or more of the above-mentioned polypropylene components with different melting points and rigidities can be used together.

[0051] Such isotactic propylene polymers (A1) can be manufactured, for example, by polymerizing propylene using a Ziegler catalyst system consisting of a solid catalyst component containing magnesium, titanium, halogens and electron donors as necessary components, an organoaluminum compound and an electron donor, or a metallocene catalyst system using a metallocene compound as one component of the catalyst, or by copolymerizing propylene with other α-olefins.

[0052] The syndiotactic propylene polymer (A2) contains at least 90 mol% of structural units from propylene and at least 10 mol% of one or more structural units selected from ethylene and α-olefins having 4 to 20 carbon atoms, preferably containing at least 91 mol% of structural units from propylene and at least 9 mol% of one or more structural units selected from ethylene and α-olefins having 4 to 20 carbon atoms (wherein the total of the two structural units is set to 100 mol%).

[0053] 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.

[0054] The melting peak of the syndiotactic propylene polymer (A2), as measured by differential scanning calorimetry (DSC), is typically in the range of above 100°C and below 120°C, preferably in the range of 100–110°C.

[0055] Syndiotactic propylene polymers (A2) can be manufactured using, for example, the methods described in International Publication No. WO2011 / 078054.

[0056] (B) Acrylic polymers

[0057] The propylene polymer (B) satisfies the following condition (b).

[0058] (b) The MFR measured according to ASTM D1238 at 230°C and 2.16 kg load is in the range of 0.01 to 100 g / 10 min and meets the following conditions (b-1) and (b-2).

[0059] (b-1) Melting point (Tm) below 100℃ or no melting point can be observed.

[0060] (b-2) has structural units derived from propylene and structural units derived from at least one olefin selected from ethylene and α-olefins having 4 to 20 carbon atoms, wherein the content of structural units derived from ethylene and at least one α-olefin selected from 4 to 20 carbon atoms is less than 40 mol%.

[0061] The following is a detailed explanation of condition (b), etc.

[0062] Condition (b)

[0063] The melt flow rate (MFR; ASTM D1238, 230°C, 2.16 kg load) of the propylene polymer (B) is 0.01–100 g / 10 min, preferably 0.1–30 g / 10 min.

[0064] Furthermore, the propylene polymer (B) satisfies conditions (b-1) and (b-2).

[0065] (Condition (b-1))

[0066] The melting point (Tm) observed in differential scanning calorimetry is below 100°C or not observed at all. "Not observed melting point" means that, in the differential scanning calorimetry range of -150 to 200°C, no melting peak with a heat of fusion greater than 1 J / g is observed. Details of the melting point determination conditions are described in the following examples.

[0067] The melting point (Tm) is preferably below 90°C, more preferably below 80°C. When the melting point (Tm) meets the above conditions, it is preferred in terms of compatibility with propylene-based polymers and low-temperature adhesion.

[0068] (Condition (b-2))

[0069] It has structural units derived from propylene and structural units derived from at least one olefin selected from ethylene and α-olefins having 4 to 20 carbon atoms, wherein the content of structural units derived from ethylene and at least one α-olefin selected from 4 to 20 carbon atoms is less than 40 mol%.

[0070] Examples of α-olefins having 4 to 20 carbon atoms include 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 ethylene and α-olefins having 4 to 20 carbon atoms.

[0071] The content of structural units derived from ethylene and at least one α-olefin selected from carbon atoms numbered 4 to 20 is preferably 40 mol% or less, more preferably 35 mol% or less.

[0072] (Other conditions)

[0073] The density of the propylene polymer (B), as measured according to JIS K7112 (density gradient tube method), is preferably 0.85–0.89 g / cm³. 3 More preferably, it is 0.86–0.88 g / cm³. 3 .

[0074] The intrinsic viscosity [η] of the propylene polymer (B) measured in decahydronaphthalene at 135°C is preferably 0.1 to 10 dL / g, more preferably 0.5 to 10 dL / g.

[0075] The propylene polymer (B) has a single glass transition temperature, which, as determined by differential scanning calorimetry (DSC), is typically in the range of -50°C to 10°C, preferably -45°C to 5°C, and more preferably -40°C to 0°C. The propylene polymer (B) is preferred when its glass transition temperature (Tg) is within the above range due to its excellent cold resistance and low-temperature properties.

[0076] Differential scanning calorimetry (DSC) measurements were performed, for example, as follows: Approximately 10.00 mg of sample was placed in a dedicated aluminum dish. Using a Seiko Instruments DSCRDC220, the temperature was increased from 30°C to 200°C at a rate of 200°C / min, held at 200°C for 5 minutes, then decreased from 200°C to -100°C at a rate of 10°C / min, held at -100°C for another 5 minutes, and then increased at a rate of 10°C / min. The glass transition temperature (Tg) was then determined based on the endothermic curve observed at this point.

[0077] Furthermore, the molecular weight distribution (Mw / Mn, polystyrene conversion, Mw: weight-average molecular weight, Mn: number-average molecular weight) of the propylene polymer (B), as measured by GPC, is preferably 3.5 or less, more preferably 3.0 or less. Additionally, the lower limit is, for example, 1.5 or more.

[0078] Regarding the propylene polymer (B), a portion of it can be graft-modified with polar monomers. Examples of polar monomers include hydroxyl-containing olefinic unsaturated compounds, amino-containing olefinic unsaturated compounds, epoxy-containing olefinic unsaturated compounds, aromatic vinyl compounds, vinyl ester compounds, and vinyl chloride. The modified propylene polymer (B) can be obtained by grafting polar monomers onto the aforementioned propylene polymer (B). When grafting the aforementioned polar monomers onto the propylene polymer (B), the polar monomer is typically used in an amount of 0.1 to 10 parts by mass, preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the propylene polymer (B). This graft polymerization is usually carried out in the presence of a free radical initiator. Organic peroxides or azo compounds can be used as free radical initiators. The free radical initiator can be directly mixed with the propylene polymer (B) and the polar monomer, or it can be used after being dissolved in a small amount of organic solvent. As for the organic solvent, any organic solvent capable of dissolving the free radical initiator can be used without particular restriction. Furthermore, reducing agents can also be used when grafting polar monomers onto propylene-based polymers (B). Using reducing agents can increase the grafting amount of polar monomers.

[0079] Graft modification of propylene polymer (B) using polar monomers can be carried out by conventionally known methods. For example, the propylene polymer (B) can be dissolved in an organic solvent, and then a polar monomer and a free radical initiator can be added to the solution. The reaction can then be carried out at a temperature of 70–200°C, preferably 80–190°C, for 0.5–15 hours, preferably 1–10 hours. Alternatively, the modified propylene polymer (B) can be produced by reacting the propylene polymer (B) with a polar monomer under solvent-free conditions using an extruder or the like. This reaction is typically carried out at a temperature above the melting point of the propylene polymer (B), specifically 120–250°C, for a typical duration of 0.5–10 minutes.

[0080] The amount of modification (grafting of polar monomers) in the resulting modified propylene polymer is typically 0.1 to 10% by mass, preferably 0.1 to 5% by mass, and more preferably 0.5 to 5% by mass.

[0081] When the propylene polymer composition of the present invention contains the above-mentioned modified propylene polymer, it exhibits excellent adhesion and compatibility with other resins, and can sometimes improve the wettability of the molded surface.

[0082] Acrylic polymers (B) can be manufactured, for example, by the method described in International Publication No. WO2004 / 087775.

[0083] Preferred embodiments of the aforementioned propylene-based polymers (B) include propylene-1-butene copolymers (B1), propylene-ethylene copolymers (B2), propylene-ethylene-1-butene copolymers (B3), and random propylene homopolymers (B4).

[0084] Regarding the propylene-1-butene copolymer (B1) mentioned above, in the propylene polymer (B) mentioned above, the content of structural units from propylene is 60 to 90 mol%, preferably 70 to 85 mol%.

[0085] The propylene-1-butene copolymer (B1) having this composition has good compatibility with the aforementioned propylene polymer (A).

[0086] Regarding the propylene-ethylene copolymer (B2), in the above-mentioned propylene polymer (B), the content of structural units derived from propylene is 60-95 mol%, preferably 75-90 mol%.

[0087] Regarding the propylene-ethylene-1-butene copolymer (B3), in the above-mentioned propylene polymer (B), the content of structural units from propylene is 60-95 mol%, preferably 70-90 mol%, the content of structural units from ethylene is 2-25 mol%, preferably 5-20 mol%, and the content of structural units from 1-butene is 3-30 mol%, preferably 5-25 mol%.

[0088] Regarding the random propylene homopolymer (B4), in the above-mentioned propylene polymer (B), the isotactic pentad fraction is 20-80%, preferably 30-60%.

[0089] Polyolefins (C) containing structural units derived from unsaturated carboxylic acids and / or their derivatives

[0090] Polyolefin (C) is obtained by modifying polyolefin with unsaturated carboxylic acids and / or their derivatives, containing structural units derived from the unsaturated carboxylic acids and / or their derivatives.

[0091] Examples of modified polyolefins include polypropylene (c1), ethylene-propylene-α-olefin copolymer (c2), and ethylene-α-olefin copolymer (c3).

[0092] The polyolefin (C) can be a single type or a mixture of two or more types. For example, it can be any one or a mixture of two or more types of modified polypropylene (C1), modified ethylene-propylene-α-olefin copolymer (C2), and modified ethylene-α-olefin copolymer (C3).

[0093] Polypropylene (C1) 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 may be one or more. 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 preferred. The content of propylene-derived structural units in the propylene-α-olefin copolymer is at least 50 mol% and less than 100%.

[0094] The intrinsic viscosity [η] of polypropylene (C1) is preferably 0.1 to 10 dl / g. When the intrinsic viscosity [η] is within this range, a composition with excellent moldability and mechanical strength can be obtained.

[0095] There are no particular limitations on the manufacturing method of polypropylene (C1). Known methods using known catalysts such as Ziegler-Natta catalysts and metallocene catalysts can be cited as examples.

[0096] As for polypropylene (C1), a crystalline polymer is preferred. In the case of copolymers, it can be a random copolymer or a block copolymer. Moreover, as long as it meets the requirements of moldability and has the strength to withstand use after being molded, there are no particular restrictions on its stereotype and molecular weight. Commercially available resins can also be used directly.

[0097] Ethylene-propylene-α-olefin copolymer (c2) is specified, for example, by (i) and (ii) below.

[0098] (i) Contains 45–90 mol% structural units from propylene, 2–25 mol% structural units from ethylene, and 3–30 mol% structural units from α-olefins with 4–20 carbon atoms. (ii) The intrinsic viscosity [η] of decahydronaphthalene at 135 °C is in the range of 0.1–10 dl / g.

[0099] As the aforementioned α-olefin, an α-olefin with 4 to 10 carbon atoms can be appropriately used, and it can be a single type or two or more types. Regarding the ratio of structural units from each monomer, it is preferably 60 to 95 mol% propylene, 2 to 25 mol% ethylene, and 3 to 30 mol% α-olefin, more preferably 70 to 90 mol% propylene, 5 to 20 mol% ethylene, and 5 to 25 mol% α-olefin.

[0100] Regarding (ii), the intrinsic viscosity [η] is more preferably in the range of 0.5 to 8, and even more preferably in the range of 0.8 to 6. When the intrinsic viscosity [η] is in the above range, an adhesive with excellent balance between flexibility and mechanical strength and high adhesion can be obtained.

[0101] There are no particular limitations on the method for manufacturing ethylene-propylene-α-olefin copolymer (c2), and it can be manufactured by known methods using known catalysts such as Ziegler-Natta catalysts and metallocene catalysts.

[0102] Ethylene-propylene-α-olefin copolymer (c2) only needs to meet the requirements of moldability and have the strength to withstand use after molding; there are no particular restrictions on its stereoregularity and molecular weight. Commercially available resins can also be used directly.

[0103] Ethylene-α-olefin copolymer (c3) is specified, for example, by (iii) and (iv) below.

[0104] (iii) Contains 50–99 mol% structural units from ethylene and 1–50 mol% structural units from α-olefins with 3–20 carbon atoms.

[0105] (iv) The intrinsic viscosity [η] in decahydronaphthalene at 135 °C is in the range of 0.1 to 10 dl / g.

[0106] As an α-olefin, it is more suitable to be an α-olefin with 3 to 10 carbon atoms, which can be a single type or two or more types. Regarding the ratio of structural units from each monomer, it is preferably 55 to 98 mol% ethylene and 2 to 45 mol% α-olefin, more preferably 60 to 95 mol% ethylene and 5 to 40 mol% α-olefin.

[0107] Regarding (iv), the intrinsic viscosity [η] is more preferably in the range of 0.5 to 8, and even more preferably in the range of 0.8 to 6. When the intrinsic viscosity [η] is in the above range, a composition with excellent balance between softness and mechanical strength and high adhesive strength can be obtained.

[0108] There are no particular limitations on the method for manufacturing ethylene-α-olefin copolymer (C3), and known methods using known catalysts such as Ziegler-Natta catalysts and metallocene catalysts can be cited.

[0109] Ethylene-α-olefin copolymers (C3) only require excellent moldability to ensure the strength required for use in the molded product; there are no particular limitations on molecular weight. Commercially available resins can also be used directly with ethylene-α-olefin copolymers (C3).

[0110] Examples of unsaturated carboxylic acids and / or their derivatives used to modify these polyolefins include unsaturated compounds having one or more carboxylic acid groups, esters of compounds having carboxylic acid groups with alkyl alcohols, and unsaturated compounds having one or more carboxylic anhydride groups. Examples of unsaturated groups in unsaturated compounds include vinyl groups, vinylidenes, 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 or their anhydrides are preferred, and maleic acid, nadic acid, or their anhydrides are particularly preferred.

[0111] Regarding the amount of structural units derived from unsaturated carboxylic acids and / or their derivatives contained in the polyolefin (C), calculated in terms of structural units derived from maleic anhydride, it is preferably 0.01 to 10% by mass, more preferably 0.1 to 5% by mass. When the amount of structural units derived from unsaturated carboxylic acids and / or their derivatives is within the above range, a resin composition with an excellent balance between moldability and adhesion can be obtained.

[0112] In the polyolefin (C), the content ratio of structural units derived from propylene, excluding those derived from the above-mentioned unsaturated carboxylic acids and / or their derivatives, is preferably 80 to 100 mol%, more preferably 90 to 100 mol%. When the content ratio of structural units derived from propylene is within the above range, a resin composition with excellent heat resistance can be obtained.

[0113] There are no particular limitations on the method for grafting unsaturated carboxylic acids and / or their derivatives. Commonly known graft polymerization methods such as solution polymerization and melt mixing can be used. For example, methods include melting a polyolefin and then adding unsaturated carboxylic acids and / or their derivatives to it for grafting, or dissolving a polyolefin in a solvent to form a solution and then adding unsaturated carboxylic acids and / or their derivatives to it for grafting.

[0114] Vinyl polymers (D)

[0115] The ethylene polymer (D) satisfies the following condition (d).

[0116] (d) is an ethylene homopolymer or a copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms, with an MFR in the range of 0.1 to 10 g / 10 minutes as measured by ASTM D1238 at 190°C and a load of 2.16 kg.

[0117] The MFR is preferably in the range of 0.1 to 8 g / 10 minutes, more preferably in the range of 0.1 to 6 g / 10 minutes. When the MFR is in the above range, a composition with excellent balance between softness and mechanical strength and high adhesive strength can be obtained.

[0118] The preferred copolymer is an ethylene-α-olefin copolymer containing 50 to 99 mol% of structural units from ethylene and 1 to 50 mol% of structural units from α-olefins selected from α-olefins with 3 to 20 carbon atoms.

[0119] Regarding the aforementioned copolymer, α-olefins with 3 to 10 carbon atoms are more suitable as α-olefins. Within this range, one or more monomers can be used alone. The preferred ratio of each monomer component is ethylene: 55 to 98 mol%, α-olefin: 2 to 45 mol%, more preferably ethylene: 60 to 95 mol%, α-olefin: 5 to 40 mol%.

[0120] There are no particular limitations on the manufacturing method of vinyl polymer (D). It can be manufactured using known methods with known catalysts such as high-pressure processes or using Ziegler-Natta catalysts or metallocene catalysts. Furthermore, as long as it satisfies the requirement of moldability and has the strength to withstand use after molding, there are no particular limitations on the molecular weight. Commercially available resins can also be used directly. Vinyl polymer (D) can also be a substance grafted with a small amount of maleic anhydride, etc., provided that the above conditions are met. Additionally, it can also be a substance that has been further modified with diamines, carbodiimides, etc., after grafting with a small amount of maleic anhydride, etc., provided that the above conditions are met.

[0121] Other ingredients

[0122] In the resin composition of the present invention, other components such as propylene-ethylene block copolymers, propylene homopolymers, propylene-ethylene random copolymers, propylene-1-butene random copolymers, propylene-ethylene-1-butene random copolymers, styrene-based elastomers, and polyethylene may be appropriately contained, without impairing the effects of the present invention. The proportion of other components in the resin composition of the present invention is preferably 20% by mass or less.

[0123] In addition, it may contain known additives such as antioxidants, ultraviolet absorbers, neutralizers, nucleating agents, light stabilizers, antistatic agents, antiblocking agents, lubricants, odor absorbers, antibacterial agents, pigments, inorganic and organic fillers, and various synthetic resins, as needed.

[0124] Resin Composition

[0125] The resin composition of the present invention can be manufactured using conventionally known methods. For example, it can be manufactured by melt-blending the above-mentioned components.

[0126] Regarding the content of propylene polymer (A), propylene polymer (B), polyolefin (C), and ethylene polymer (D) in the resin composition of the present invention, when the total content of propylene polymer (A), propylene polymer (B), polyolefin (C), and ethylene polymer (D) is set to 100 parts by mass, the content of propylene polymer (A) is 10 to 99.9 parts by mass, the content of propylene polymer (B) is 0 to 40 parts by mass, the content of polyolefin (C) is 0.1 to 20 parts by mass, and the content of ethylene polymer (D) is 0 to 40 parts by mass; preferably, the content of propylene polymer (A) is 10 to 94.9 parts by mass. The propylene polymer (B) comprises 5 to 40 parts by mass, the polyolefin (C) comprises 0.1 to 20 parts by mass, and the ethylene polymer (D) comprises 0 to 40 parts by mass; more preferably, the propylene polymer (A) comprises 10 to 89.5 parts by mass, the propylene polymer (B) comprises 5 to 40 parts by mass, the polyolefin (C) comprises 0.5 to 20 parts by mass, and the ethylene polymer (D) comprises 5 to 40 parts by mass; even more preferably, the propylene polymer (A) comprises 20 to 84 parts by mass, the propylene polymer (B) comprises 10 to 35 parts by mass, the polyolefin (C) comprises 1 to 20 parts by mass, and the ethylene polymer (D) comprises 5 to 35 parts by mass.

[0127] Furthermore, it is preferred that the propylene polymer (A) comprises 10 to 94.9 parts by mass, the propylene polymer (B) comprises 0 to 40 parts by mass, the polyolefin (C) comprises 0.1 to 20 parts by mass, and the ethylene polymer (D) comprises 5 to 40 parts by mass, wherein the density of the ethylene polymer (D) is 0.87 g / cm³. 3 The following is also a more preferred method. The density of the above-mentioned ethylene polymer (D) is 0.87 g / cm³.3 In the following cases, the density is further preferably 0.80 g / cm³. 3 above.

[0128] When the content of the above-mentioned components in the resin composition of the present invention is within the above-mentioned range, the adhesiveness, especially the adhesiveness at low heat, specifically the adhesiveness at 140°C or below, is high, and the film containing the layer obtained by the present composition is not prone to whitening even during deformation processing.

[0129] The resin composition of the present invention preferably has a molecular weight filtration rate (MFR) of 0.1 g / 10 min or more and 30 g / 10 min or less, more preferably 1 g / 10 min or more and 20 g / 10 min or less, as measured according to ASTM D1238 at 230°C and 2.16 kg load. When the MFR is within the above range, a resin composition suitable for various film forming processing methods such as casting, blow molding, and extrusion lamination can be obtained. Furthermore, even when film forming is performed under high-speed molding conditions, the orientation of the molecular chains is easily relaxed, suppressing whitening during subsequent deformation processing.

[0130] Regarding whitening during deformation processing, it occurs when microcracks are generated. When microcracks are generated in the film, it can be considered that the insulation of the battery packaging material deteriorates.

[0131] Single-layer or multi-layer film

[0132] The single-layer and multi-layer films of the present invention are single-layer or multi-layer films comprising at least one layer containing the above-described resin composition. That is, the single-layer film of the present invention is a film composed of a layer containing the above-described resin composition, and the multi-layer film is a multi-layer film comprising at least one layer containing the above-described resin composition.

[0133] The single-layer and multi-layer films of the present invention exhibit excellent resistance to whitening during deformation processing. Therefore, when the single-layer and multi-layer films of the present invention are used as food packaging materials, building or industrial materials, or components for secondary batteries such as lithium-ion batteries, whitening is less likely to occur during secondary processing of the film, such as deep drawing and bending. Therefore, the single-layer and multi-layer films of the present invention can be suitable for use as food packaging materials, building or industrial materials, and components for secondary batteries.

[0134] In particular, polypropylene resins have been conventionally used as packaging materials for forming the outer packaging of lithium-ion batteries. However, by using a specific combination of the aforementioned propylene polymer (A), propylene polymer (B), polyolefin (C), and ethylene polymer (D), the present invention is able to prevent whitening, which is unavoidable with conventional polypropylene resins.

[0135] The multilayer film of the present invention, for example, comprises at least one layer containing the above-described resin composition, and one or both sides of the layer containing the above-described composition are in contact with other layers contained in the multilayer film. Examples of other layers in contact with the layer containing the above-described composition include metal layers, polyolefin layers, and polar resin layers. Examples of metal layers include aluminum layers, copper layers, and stainless steel layers; examples of polyolefin layers include polypropylene layers, poly(4-methylpentene) layers, and polyethylene layers; and examples of polar resin layers include polyamide layers, EVOH layers, PET layers, and PBT layers.

[0136] The single-layer and multi-layer films of the present invention can be obtained by melt extrusion molding, and can be manufactured by industrially common methods such as casting, blow molding, and extrusion lamination.

[0137] <Components for secondary batteries>

[0138] Examples of secondary battery components for which the membrane of the present invention is used include tab membranes for lithium-ion batteries (hereinafter also referred to as "tab membranes") and outer packaging materials for lithium-ion batteries (hereinafter also referred to as "outer packaging materials"). The tab is a terminal for electrical input and output between the battery's electrodes and the outside, and has a metal layer as a lead substrate and a tab membrane formed on at least one side of the lead substrate.

[0139] In the tab film of the present invention, a layer (film) formed by the composition of the present invention is bonded to the lead substrate, and other layers may be provided as needed. The tab film covers a portion of the lead substrate (lead conductor) and is formed for bonding to the inner surface of the outer packaging material of the lithium-ion battery. The tab film of the present invention has excellent low-temperature adhesion, therefore, the bonding temperature with the lead substrate can be lower than that of the prior art. As a result, the heat load during bonding can be reduced, and productivity can be improved. The bonding temperature with the lead substrate is not particularly limited as long as it is a temperature that can melt the tab film, but is preferably 100-200°C, more preferably 130-180°C. Furthermore, the heating time is not particularly limited, but is preferably 1 second to 10 minutes, more preferably 1 second to 1 minute.

[0140] As one embodiment of the tab membrane of the present invention, a laminated membrane having an adhesive layer comprising the composition of the present invention and a heat-resistant layer can be cited. In a lithium-ion battery, the adhesive layer is bonded to a lead substrate, and the heat-resistant layer is bonded to the inner surface of an outer packaging material.

[0141] As a lead substrate connected to the positive electrode of a lithium-ion battery, a lead conductor made of aluminum, titanium, or an alloy containing at least one of these materials can be used, for example. Furthermore, as a lead substrate connected to the negative electrode of a lithium-ion battery, a lead conductor made of copper, nickel, or an alloy containing at least one of these materials can be used, for example.

[0142] Examples of heat-resistant layers include those comprising polyolefin resins. Examples of such polyolefin resins include thermoplastic polyolefin resins such as polyethylene and polypropylene. Only one type or more types may be used. From the viewpoint of heat resistance, polypropylene resin is preferred. Furthermore, the polyolefin resin may undergo cross-linking.

[0143] As for the outer packaging material of the present invention, there is no particular limitation as long as it has an adhesive layer containing the composition of the present invention. For example, a laminated film consisting of a substrate layer, an aluminum foil layer, an adhesive layer, and a sealing layer can be cited.

[0144] Example

[0145] The present invention will now be described in more detail with reference to embodiments, but the present invention is not limited to these embodiments in any way.

[0146] [Conditions for determining physical properties]

[0147] Melt Flow Rate (MFR)

[0148] According to ASTM D1238, the MFR of propylene polymers was determined at 230°C and 2.16 kg load, and the MFR of ethylene polymers was determined at 190°C and 2.16 kg load.

[0149] <Density>

[0150] Density was determined according to JIS K7112 (density gradient tube method).

[0151] Composition of Polyolefins

[0152] Regarding the content ratio of structural units from α-olefins and structural units from ethylene in polyolefins, through... 13 C-NMR quantification is performed using the following apparatus and conditions.

[0153] A JECX400P nuclear magnetic resonance (NMR) instrument manufactured by NEC Corporation was used. 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 The conditions are: C (100MHz), single-pulse proton decoupling sequence, pulse width of 4.62μs (45° pulse), repetition time of 5.5 seconds, cumulative number of times of 8000, and chemical shift reference value of 29.73ppm.

[0154] Melting point

[0155] The melting point was determined using a differential scanning calorimeter (DSC) as described below. Approximately 5 mg of the sample was sealed in an aluminum dish and heated from room temperature to 230°C at a rate of 10°C / min. The sample was held at 230°C for 10 minutes to completely melt it. It was then cooled to -20°C at a rate of 10°C / min, allowed to stand at -20°C for 10 minutes, and then reheated to 230°C at a rate of 10°C / min. The peak temperature obtained from this second heating test was taken as the melting point (Tm).

[0156] <Grafting Modification Quantity>

[0157] The amount of structural units derived from unsaturated carboxylic acids and / or their derivatives (grafting modification amount) was determined by infrared absorption analysis of the peaks from the aforementioned structural units (1790 cm⁻¹ when using maleic anhydride). ﹣1 The intensity of the ) is quantified using a pre-made standard curve.

[0158] <Whitening resistance>

[0159] Using an extrusion molding machine with a T-die and a screw with a diameter of 50 mm and an effective length L / D = 28, the adhesive obtained in the examples and comparative examples was extruded at 240°C to produce a single-layer film with a thickness of 100 μm.

[0160] Along a direction parallel to the flow direction of the monolayer film, JIS K6251 No. 2 dumbbell plates were punched from the obtained monolayer film. The hue L value was determined using a Konica Minolta CM-3700A spectrophotometer employing the specular reflection elimination method. Further, the hue L value of the JIS K6251 No. 2 dumbbell plates, exhibiting elongation deformation of 5 mm, 10 mm, or 20 mm at a crosshead speed of 200 mm / min, was determined using a tensile testing machine. The change in hue L value after 5 mm elongation was defined as ΔL(5 mm), the change after 10 mm elongation as ΔL(10 mm), and the change after 20 mm elongation as ΔL(20 mm).

[0161] <Membrane Formability>

[0162] The adhesives obtained in the examples and comparative examples were extruded using an extruder with a T-die, employing a screw with a diameter of 50 mm and an effective length L / D = 28 at 240°C. The extrusion was collected using a cooling roller set to 25°C to form a single-layer 100 μm film. Single-layer films were formed under three conditions: collection speeds of 5 m / min, 10 m / min, and 20 m / min. The film formability of the single-layer films obtained under each condition was evaluated according to the following criteria.

[0163] Formability ○: No peel marks are produced on the film surface when passing through the cooling roller.

[0164] Formability △: Slight peel marks were produced on the film surface when passing through the cooling roller.

[0165] Formability ×: Obvious peel marks were produced on the film surface when passing through the cooling roller.

[0166] <Adhesion>

[0167] The adhesive obtained in the examples and comparative examples and commercially available polypropylene (F327, MFR: 7 manufactured by Priman Polymers Co., Ltd.) were co-extruded at 240°C using an extruder with a T-die and a screw with a diameter of 50 mm and an effective length L / D = 28. The extruded adhesive and polypropylene were then laminated in the feed block with the adhesive as the inner layer and the polypropylene as the outer layer to produce a multilayer film with both the inner and outer layers being 50 μm thick and 100 μm thick.

[0168] The inner layer of the obtained multilayer film is overlapped with the aluminum foil layer of a commercially available aluminum laminate film (aluminum foil / polyethylene terephthalate: 20 / 12μm), and the composite is produced by heat sealing using a heat sealer under the conditions of sealing temperature of 120℃, 130℃ or 140℃, sealing pressure of 0.1MPa and sealing time of 10 seconds.

[0169] The adhesive strength (in N / 15 mm) of the composites obtained at various sealing temperatures was determined using a tensile testing machine at room temperature (23°C) via the T-peel method. The crosshead speed was set to 300 mm / min.

[0170] [The polyolefin used]

[0171] The polyolefins used in the examples and comparative examples are shown below. Furthermore, unless otherwise specified, these polyolefins were prepared by polymerization using conventional methods.

[0172] PP-1: Metallocene-based random polypropylene

[0173] (MFR: 8g / 10 minutes, density: 0.89g / cm³) 3 Propylene content: 94 mol%, ethylene content: 6 mol%, melting point: 105℃

[0174] PP-2: Metallocene-based random polypropylene

[0175] (MFR: 7g / 10 minutes, density: 0.90g / cm³) 3 Propylene content: 96 mol%, Ethylene content: 4 mol%, Melting point: 125℃

[0176] PP-3: Metallocene-based random polypropylene

[0177] (MFR: 7g / 10 minutes, density: 0.89g / cm³)3 Propylene content: 85 mol%, 1-Butene content: 15 mol%, Melting point: 98℃

[0178] PBR: Propylene-1-butene random copolymer

[0179] (MFR: 7g / 10 minutes, density: 0.88g / cm³) 3 Propylene content: 74 mol%, 1-Butene content: 26 mol%, Melting point: 75℃

[0180] PER: Propylene-ethylene random copolymer

[0181] (MFR: 7g / 10 minutes, density: 0.87g / cm³) 3 Propylene content: 84 mol%, Ethylene content: 16 mol%, Melting point: 60℃

[0182] • Modified PP: Modified homopolymer polypropylene

[0183] (MFR: 100g / 10 minutes, density: 0.90g / cm³) 3 Maleic anhydride grafting amount: 1.5% by mass

[0184] • EPR: Ethylene-propylene random copolymer

[0185] (MFR: 0.6g / 10min, density: 0.87g / cm³) 3 Ethylene content: 80 mol%, propylene content: 20 mol%.

[0186] [Example 1]

[0187] <Adhesive Manufacturing>

[0188] A resin composition was obtained by melt-blending 80 parts by weight of PP-1, 10 parts by weight of EPR, and 10 parts by weight of modified PP at 230°C using a single-screw extruder. This composition was used as adhesive 1.

[0189] [Examples 2-4, Comparative Examples 1-5]

[0190] In Examples 2-4 and Comparative Examples 1-5, resin compositions were manufactured according to the formulations shown in Table 1 using the same method as in Example 1. The composition obtained in Example 2 was used as adhesive 2, the composition obtained in Example 3 was used as adhesive 3, the composition obtained in Example 4 was used as adhesive 4, the composition obtained in Comparative Example 1 was used as adhesive 5, the composition obtained in Comparative Example 2 was used as adhesive 6, the composition obtained in Comparative Example 3 was used as adhesive 7, the composition obtained in Comparative Example 4 was used as adhesive 8, and the composition obtained in Comparative Example 5 was used as adhesive 9.

[0191] The MFR and density of the adhesives obtained in the examples and comparative examples, the whitening resistance and formability evaluation results of the monolayer films obtained by the adhesives, and the adhesion evaluation results of the multilayer films obtained by the adhesives are shown in Table 1. Furthermore, regarding adhesive 9, since surface roughness of the film caused by peel marks occurred during the fabrication of the multilayer film, adhesion strength was not measured.

[0192] [Table 1]

[0193]

Claims

1. A resin composition, characterized in that: The content of propylene polymer (A) satisfying condition (a) below is 10 to 89.5 parts by weight. The content of the propylene polymer (B) that satisfies condition (b) below is 5 to 40 parts by weight. The content of polyolefin (C) containing structural units derived from unsaturated carboxylic acids and / or their derivatives is 0.5 to 20 parts by weight. The content of the vinyl polymer (D) that satisfies the following condition (d) is 5 to 40 parts by mass. The total content of components (A), (B), (C), and (D) is set at 100 parts by mass. The unsaturated carboxylic acid and / or its derivatives are unsaturated compounds having one or more carboxylic acid groups, esters of compounds having carboxylic acid groups and alkyl alcohols, or unsaturated compounds having one or more carboxylic anhydride groups. (a) The melting point (Tm) observed in differential scanning calorimetry is between 100 °C and 115 °C; (b) The MFR measured according to ASTM D1238 at 230°C and a load of 2.16 kg is in the range of 0.01 to 100 g / 10 minutes, and meets the following conditions (b-1) and (b-2): (b-1) The melting point (Tm) observed in differential scanning calorimetry is below 100°C or the melting point (Tm) cannot be observed. (b-2) Contains structural units derived from propylene and structural units derived from at least one olefin selected from ethylene and α-olefins having 4 to 20 carbon atoms, wherein the total content of structural units derived from at least one olefin selected from ethylene and α-olefins having 4 to 20 carbon atoms is less than 40 mol%. (d) is an ethylene homopolymer or a copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms, with an MFR in the range of 0.1 to 10 g / 10 minutes as measured by ASTM D1238 at 190°C and a load of 2.16 kg.

2. The resin composition according to claim 1, characterized in that: The density of the ethylene polymer (D) is 0.87 g / cm³. 3 the following.

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

4. A multilayer film, characterized in that: It comprises at least one layer containing the resin composition of claim 1 or 2, and at least two other layers besides the layer containing the resin composition, wherein two sides of the layer containing the resin composition are in contact with the other layers.

5. A multilayer film, characterized in that: The material comprises at least one layer containing the 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 resin composition is in contact with at least one of the metal-containing layer, the polyolefin layer, and the polar resin layer.

6. A food packaging material, characterized in that: It includes the single-layer or multi-layer film as described in claim 3, or the multi-layer film as described in claim 4 or 5.

7. A building or industrial material, characterized in that: It includes the single-layer or multi-layer film as described in claim 3, or the multi-layer film as described in claim 4 or 5.

8. A component for a secondary battery, characterized in that: It includes the single-layer or multi-layer film as described in claim 3, or the multi-layer film as described in claim 4 or 5.

9. The component for a secondary battery as described in claim 8, characterized in that: The secondary battery component is the outer packaging material for lithium-ion batteries.

10. The component for a secondary battery as described in claim 8, characterized in that: The secondary battery component is a tab diaphragm for lithium-ion batteries.

11. A method for manufacturing a single-layer or multi-layer film, characterized in that: The resin composition according to claim 1 or 2 is melt-extruded into shape.

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