Polyolefin-based resin composition, film, and packaging bag

Abstract

To provide a polyolefin-based resin composition capable of producing film with relatively excellent hiding properties, a film including the polyolefin-based resin composition, and a packaging bag including the film.SOLUTION: A polyolefin-based resin composition (A) according to the present invention comprises a polyolefin-based resin and aluminum atoms existing in the form of flake-like particles with an average thickness of 10 nm or more and 1,000 nm or less, and an aspect ratio of 3 or more. The content of the aluminum atoms is 100 wt. ppm or more and 10,000 wt. ppm or less based on the entire polyolefin-based resin composition (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyolefin resin composition, a film containing the polyolefin resin composition, and a packaging bag containing the film. [Background technology]

[0002] Packaging materials used in food packaging bags and the like are in demand for raw materials with adequate hiding power in order to improve the visibility of printing on the surface. Examples of such raw materials include films with a thin printed layer on the surface, and films containing a polyolefin resin composition containing an inorganic substance such as aluminum.

[0003] For example, Patent Document 1 discloses a film made from pellets obtained by blending a laminated film having an aluminum vapor-deposited layer with a thermoplastic resin film or pulverized thermoplastic resin that does not have an aluminum vapor-deposited layer, and melt-kneading the resulting pellets using a melt-kneading extruder.

[0004] Furthermore, for example, Patent Document 2 discloses a resin film material that uses a resin material containing a laminate with a resin layer having a metal vapor-deposited layer as a raw material, and contains the metal as particles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-035272 [Patent Document 2] International Publication No. 2022 / 124146 Summary of the Invention [Problem to be solved by the invention]

[0006] However, neither the film nor the resin film material has sufficient hiding power, and there is room for improvement.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a polyolefin-based resin composition that can produce a film with relatively excellent concealment properties, a film containing the polyolefin-based resin composition, and a packaging bag containing the film. [Means for solving the problem]

[0008] The polyolefin resin composition (A) according to the present invention is a polyolefin resin composition (A) comprising a polyolefin resin and aluminum atoms present in the form of flaky particles having an average thickness of 10 nm or more and 1,000 nm or less and an aspect ratio of 3 or more, and the content of the aluminum atoms is 100 wtppm or more and 10,000 wtppm or less based on the entire polyolefin resin composition (A).

[0009] The film of the present invention comprises a polyolefin resin composition (A) that contains a polyolefin resin and aluminum atoms that are present in the form of flaky particles having an average thickness of 10 nm or more and 1,000 nm or less and an aspect ratio of 3 or more, the content of the aluminum atoms being 100 wtppm or more and 10,000 wtppm or less based on the entire film, and the aluminum atoms are derived from an aluminum-based vapor-deposited film.

[0010] The film according to the present invention is a film containing a resin composition obtained by mixing a polyolefin-based resin composition (A) and a polyolefin-based resin composition (B), wherein the polyolefin-based resin composition (A) is the above-mentioned polyolefin-based resin composition (A), and the polyolefin-based resin composition (B) contains a polyolefin-based resin and does not contain aluminum atoms.

[0011] The film according to the present invention is a film in which a layer containing a polyolefin-based resin composition (A) and a layer containing a polyolefin-based resin composition (B) are laminated together, the polyolefin-based resin composition (A) being the above-mentioned polyolefin-based resin composition (A), and the polyolefin-based resin composition (B) containing a polyolefin-based resin and not containing aluminum atoms.

[0012] The packaging bag according to the present invention includes the above-described film. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a polyolefin resin composition that can produce a film with relatively excellent hiding properties, a film containing the polyolefin resin composition, and a packaging bag containing the film. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0015] (Polyolefin Resin Composition (A)) The polyolefin resin composition (A) according to this embodiment contains a polyolefin resin and aluminum atoms.

[0016] [Polyolefin resin] The polyolefin resin is a resin containing an olefin polymer.

[0017] Examples of the polyolefin resin contained in the polyolefin resin composition (A) include polyethylene resins, polypropylene resins, etc. Among these, the polyolefin resin is preferably at least one of polyethylene resins and polypropylene resins, from the viewpoint of obtaining a film with relatively excellent hiding power.

[0018] <Polypropylene resin> The polypropylene resin is a resin containing a propylene polymer.

[0019] A propylene-based polymer is a polymer containing more than 50% by mass of monomer units derived from propylene. Examples of propylene-based polymers include propylene homopolymers, random copolymers of propylene and monomers other than propylene, and heterophasic propylene polymer materials. A polypropylene-based resin may contain only one type of propylene-based polymer, or may contain two or more types of propylene-based polymers.

[0020] From the viewpoint of improving the rigidity and impact resistance of the molded article, the polypropylene-based resin preferably contains, as a propylene-based polymer, at least one selected from the group consisting of a propylene homopolymer, a random copolymer of propylene and a monomer other than propylene, and a heterophasic propylene polymer material, and more preferably contains a random copolymer of propylene and a monomer other than propylene.

[0021] The propylene homopolymer can be produced, for example, by carrying out a polymerization step in which propylene is polymerized using a polymerization catalyst.

[0022] Examples of the polymerization catalyst include Ziegler catalysts; Ziegler-Natta catalysts; catalysts containing a compound of a transition metal of Group 4 of the periodic table having a cyclopentadienyl ring and an alkylaluminoxane; catalysts containing a compound of a transition metal of Group 4 of the periodic table having a cyclopentadienyl ring, a compound that reacts with the transition metal compound to form an ionic complex, and an organoaluminum compound; and modified catalysts in which a catalyst component (a compound of a transition metal of Group 4 of the periodic table having a cyclopentadienyl ring, a compound that forms an ionic complex, an organoaluminum compound, etc.) is supported on inorganic particles (silica, clay minerals, etc.).

[0023] Examples of the polymerization catalyst include catalysts described in JP-A-61-218606, JP-A-5-194685, JP-A-7-216017, JP-A-9-316147, JP-A-10-212319, JP-A-2004-182981, JP-A-2010-168545, and JP-A-2011-246699.

[0024] Furthermore, a polymer obtained by prepolymerizing propylene in the presence of the above polymerization catalyst can also be used as the polymerization catalyst.

[0025] Examples of polymerization methods include bulk polymerization, solution polymerization, and gas phase polymerization. Here, bulk polymerization refers to a method in which polymerization is carried out using an olefin that is liquid at the polymerization temperature as a medium. Solution polymerization refers to a method in which polymerization is carried out in an inert hydrocarbon solvent such as propane, butane, isobutane, pentane, hexane, heptane, or octane. Gas phase polymerization refers to a method in which gaseous monomers are used as a medium and the gaseous monomers are polymerized in the medium.

[0026] The polymerization method may be, for example, a batch method, a continuous method, or a combination thereof. The polymerization method may be a multi-stage method in which a plurality of polymerization reactors are connected in series.

[0027] From the viewpoint of industrial and economical excellence, the polymerization method is preferably a continuous gas phase polymerization method or a bulk-gas phase polymerization method in which bulk polymerization and gas phase polymerization are carried out continuously.

[0028] Various conditions in the polymerization step (polymerization conditions such as polymerization temperature, polymerization pressure, monomer concentration, catalyst input amount, and polymerization time) may be appropriately determined depending on the molecular structure of the target polymer.

[0029] In the method for producing a propylene homopolymer, other steps may be carried out before or after the polymerization step. For example, after the polymerization step, the polymer may be dried at a temperature equal to or lower than the melting point of the polymer, as necessary, to remove residual solvent contained in the polymer and ultralow molecular weight oligomers produced as by-products during the production. Examples of drying methods include those described in JP-A-55-75410 and JP-A-2565753.

[0030] The random copolymer of propylene and a monomer other than propylene contains monomer units derived from propylene and monomer units derived from a monomer other than propylene. In the random copolymer, the content of the monomer units derived from a monomer other than propylene is preferably 0.01% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, relative to the total mass of the copolymer (100% by mass).

[0031] Examples of monomers other than propylene include ethylene and α-olefins having 4 to 12 carbon atoms. In this specification, α-olefins are aliphatic unsaturated hydrocarbons having a carbon-carbon unsaturated double bond at the α-position. Examples of α-olefins having 4 to 12 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 4-methyl-1-hexene.

[0032] The monomer other than propylene is preferably at least one selected from the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms, more preferably at least one selected from the group consisting of ethylene, 1-butene, 1-hexene, and 1-octene, and even more preferably at least one selected from the group consisting of ethylene and 1-butene.

[0033] Examples of random copolymers of propylene and a monomer other than propylene include propylene-ethylene random copolymers, propylene-1-butene random copolymers, propylene-1-hexene random copolymers, propylene-1-octene random copolymers, propylene-ethylene-1-butene random copolymers, propylene-ethylene-1-hexene random copolymers, and propylene-ethylene-1-octene random copolymers.

[0034] A random copolymer of propylene and a monomer other than propylene can be produced, for example, by polymerizing propylene and a monomer other than propylene in accordance with the polymerization catalyst, polymerization method, polymerization system, and polymerization conditions that can be used in the production of the above-mentioned propylene homopolymer.

[0035] The heterophasic propylene polymer material is a mixture containing a polymer I containing monomer units derived from propylene, and a polymer II containing monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms and monomer units derived from propylene.

[0036] The heterophasic propylene polymer material can be produced, for example, by carrying out a first polymerization step of polymerizing polymer I and a second polymerization step of polymerizing polymer II. These polymerization steps can be carried out using the same polymerization catalyst, polymerization method, polymerization system, and polymerization conditions as those usable in the production of the above-mentioned propylene homopolymer.

[0037] The heterophasic propylene polymer material may be such that the sum of polymer I and polymer II contained in the heterophasic propylene polymer material is 100% by mass relative to the total mass of the heterophasic propylene polymer material (100% by mass).

[0038] Polymer I may contain 70% by mass or more of monomer units derived from propylene (where the total mass of Polymer I is 100% by mass). Polymer I may be, for example, a propylene homopolymer, or may contain monomer units derived from a monomer other than propylene. When Polymer I contains monomer units derived from a monomer other than propylene, the content thereof is usually 0.01% by mass or more and 30% by mass or less, relative to the total mass of Polymer I (100% by mass).

[0039] Examples of the monomer other than propylene include ethylene and α-olefins having 4 or more carbon atoms. Examples of the α-olefins having 4 or more carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 4-methyl-1-hexene.

[0040] The monomer other than propylene is preferably at least one selected from the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms, more preferably at least one selected from the group consisting of ethylene, 1-butene, 1-hexene, and 1-octene, and even more preferably at least one selected from the group consisting of ethylene and 1-butene.

[0041] Examples of polymer I containing monomer units derived from a monomer other than propylene include propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, and propylene-ethylene-1-octene copolymer.

[0042] Polymer I is preferably a propylene homopolymer, a propylene-ethylene copolymer, a propylene-1-butene copolymer, or a propylene-1-hexene copolymer, and more preferably a propylene homopolymer.

[0043] The content of polymer I is usually 30% by mass or more and 99% by mass or less, preferably 50% by mass or more and 95% by mass or less, and more preferably 60% by mass or more and 90% by mass or less, based on the total mass of the heterophasic propylene polymerization material (100% by mass).

[0044] As described above, polymer II contains monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms, and monomer units derived from propylene. Examples of α-olefins having 4 to 12 carbon atoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 4-methyl-1-hexene.

[0045] Polymer II preferably contains 30% by mass or more of monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms, and also contains monomer units derived from propylene (where the total mass of Polymer II is taken as 100% by mass).

[0046] In polymer II, the content of monomer units derived from at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms is usually 1% by mass or more and 80% by mass or less, preferably 20% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 60% by mass or less (where the total mass of polymer II is taken as 100% by mass).

[0047] In Polymer II, the at least one α-olefin selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms is preferably at least one selected from the group consisting of ethylene and α-olefins having 4 to 10 carbon atoms, more preferably at least one selected from the group consisting of ethylene, 1-butene, 1-hexene, 1-octene, and 1-decene, and even more preferably at least one selected from the group consisting of ethylene and 1-butene.

[0048] Examples of polymer II include propylene-ethylene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, propylene-ethylene-1-octene copolymer, propylene-ethylene-1-decene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, propylene-1-decene copolymer, etc. Among these, polymer II is preferably a propylene-ethylene copolymer, a propylene-1-butene copolymer, or a propylene-ethylene-1-butene copolymer, and more preferably a propylene-ethylene copolymer.

[0049] The content of polymer II is usually 1% by mass or more and 70% by mass or less, preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less, relative to the total mass of the heterophasic propylene polymerization material (100% by mass).

[0050] Examples of heterophasic propylene polymer materials include (propylene)-(propylene-ethylene) polymer materials, (propylene)-(propylene-ethylene-1-butene) polymer materials, (propylene)-(propylene-ethylene-1-hexene) polymer materials, (propylene)-(propylene-ethylene-1-octene) polymer materials, (propylene)-(propylene-1-butene) polymer materials, (propylene)-(propylene-1-hexene) polymer materials, (propylene)-(propylene-1-octene) polymer materials, and (propylene)-(propylene-1-decene) polymer materials. materials, (propylene-ethylene)-(propylene-ethylene) polymerization materials, (propylene-ethylene)-(propylene-ethylene-1-butene) polymerization materials, (propylene-ethylene)-(propylene-ethylene-1-hexene) polymerization materials, (propylene-ethylene)-(propylene-ethylene-1-octene) polymerization materials, (propylene-ethylene)-(propylene-ethylene-1-decene) polymerization materials, (propylene-ethylene)-(propylene-1-butene) polymerization materials, (propylene-ethylene)-(propylene-1-hexene) polymerization materials, (propylene-ethylene) (propylene)-(propylene-1-octene) polymerization materials, (propylene-ethylene)-(propylene-1-decene) polymerization materials, (propylene-1-butene)-(propylene-ethylene) polymerization materials, (propylene-1-butene)-(propylene-ethylene-1-butene) polymerization materials, (propylene-1-butene)-(propylene-ethylene-1-hexene) polymerization materials, (propylene-1-butene)-(propylene-ethylene-1-octene) polymerization materials, (propylene-1-butene)-(propylene-ethylene-1-decene) polymerization materials, (propylene-1-butene)-(propylene-ethylene-1-decene) polymerization materials, (propylene-1-butene)-( (propylene-1-butene) polymerization materials, (propylene-1-butene)-(propylene-1-hexene) polymerization materials, (propylene-1-butene)-(propylene-1-octene) polymerization materials, (propylene-1-butene)-(propylene-1-decene) polymerization materials, (propylene-1-hexene)-(propylene-1-hexene) polymerization materials, (propylene-1-hexene)-(propylene-1-octene) polymerization materials, (propylene-1-hexene)-(propylene-1-decene) polymerization materials, (propylene-1-octene)-(propylene-1-octene) polymerization materials,(propylene-1-octene)-(propylene-1-decene) polymer materials, etc.

[0051] Here, the expression "(propylene)-(propylene-ethylene) polymer material" means "a heterophasic propylene polymer material in which polymer I is a propylene homopolymer and polymer II is a propylene-ethylene copolymer." The same applies to other similar expressions.

[0052] The heterophasic propylene polymeric material is preferably a (propylene)-(propylene-ethylene) polymeric material, a (propylene)-(propylene-ethylene-1-butene) polymeric material, a (propylene-ethylene)-(propylene-ethylene) polymeric material, a (propylene-ethylene)-(propylene-ethylene-1-butene) polymeric material, or a (propylene-1-butene)-(propylene-1-butene) polymeric material, and more preferably a (propylene)-(propylene-ethylene) polymeric material.

[0053] From the viewpoint of improving the molding processability of the polypropylene resin composition, the melt flow rate (MFR) of the propylene polymer is preferably 1 g / 10 min or more and 300 g / 10 min or less, and more preferably 10 g / 10 min or more and 200 g / 10 min or less.

[0054] The melt flow rate (MFR) of a propylene polymer is measured by Method A under conditions of a temperature of 230°C and a load of 2.16 kg in accordance with the method specified in JIS K7210-1:2014 and K7210-2:2014.

[0055] <Polyethylene resin> The polyethylene resin is a resin containing an ethylene polymer.

[0056] An ethylene-based polymer is a polymer containing more than 50% by mass of monomer units derived from ethylene. Examples of ethylene-based polymers include ethylene homopolymers, copolymers of ethylene and α-olefins, and copolymers of ethylene and α-olefins substituted with alicyclic compounds. The ethylene-based polymer may also be a mixture of an ethylene homopolymer and a copolymer of ethylene and α-olefins. The amount of monomer units derived from α-olefins in the ethylene-based polymer is not particularly limited and may be, for example, 4.0% by mass or more and 20% by mass or less.

[0057] Examples of ethylene homopolymers include high-pressure low-density polyethylene (LDPE), which is produced by high-pressure radical polymerization using a radical initiator. High-pressure low-density polyethylene (LDPE) is a polymer in which repeating ethylene units are randomly bonded to form a branched structure. High-pressure low-density polyethylene (LDPE) has a density of, for example, 910 to 935 kg / m 3 may be.

[0058] Examples of copolymers of ethylene and α-olefins include linear low-density polyethylene having crystallinity, and elastomers of copolymers of ethylene and α-olefins having low crystallinity and rubber-like elastic properties.

[0059] The density of the linear low-density polyethylene is, for example, 900 to 940 kg / m 3 The density of the elastomer of the copolymer of ethylene and α-olefin may be, for example, 860 to 900 kg / m 3 may be.

[0060] Examples of the α-olefin include α-olefins having 3 to 10 carbon atoms. Examples of the α-olefins having 3 to 10 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, and 3-methyl-1-butene. Preferred are α-olefins having 4 to 10 carbon atoms, and more preferred are 1-butene, 1-hexene, and 1-octene.

[0061] Examples of copolymers of ethylene and α-olefins include ethylene-1-butene copolymers, ethylene-1-hexene copolymers, ethylene-1-octene copolymers, ethylene-1-decene copolymers, ethylene-(3-methyl-1-butene) copolymers, etc. The copolymer of ethylene and α-olefins may be one of these copolymers alone or a mixture of two or more thereof.

[0062] Examples of α-olefins substituted with alicyclic compounds include vinylcyclohexane.

[0063] The melt flow rate (MFR) of the ethylene polymer is preferably 0.5 g / 10 min or more and 50 g / 10 min or less, more preferably 1 g / 10 min or more and 30 g / 10 min or less, and even more preferably 1 g / 10 min or more and 20 g / 10 min or less.

[0064] The melt flow rate (MFR) of an ethylene polymer is measured by Method A under conditions of a temperature of 190°C and a load of 2.16 kg in accordance with the method specified in JIS K7210-1:2014 and K7210-2:2014.

[0065] The ethylene polymer can be produced by a known polymerization method using a known polymerization catalyst.

[0066] Examples of polymerization catalysts include homogeneous catalyst systems such as metallocene catalysts, Ziegler catalyst systems, and Ziegler-Natta catalyst systems. Examples of homogeneous catalyst systems include a catalyst system consisting of a Group 4 transition metal compound having a cyclopentadienyl ring and an alkylaluminoxane, a catalyst system consisting of a Group 4 transition metal compound having a cyclopentadienyl ring, a compound that reacts with the metal compound to form an ionic complex, and an organoaluminum compound, a catalyst system in which inorganic particles such as silica or clay minerals are supported and modified with catalytic components such as a Group 4 transition metal compound having a cyclopentadienyl ring, a compound that forms an ionic complex, and an organoaluminum compound, and a prepolymerization catalyst system prepared by prepolymerizing ethylene or an α-olefin in the presence of the above catalyst system.

[0067] Furthermore, a radical initiator can be used as a polymerization catalyst for high-pressure low-density polyethylene (LDPE).

[0068] [Aluminum atom] The aluminum atoms contained in the polyolefin resin composition (A) are present in the form of flaky particles having an average thickness of 10 nm or more and 1,000 nm or less and an aspect ratio of 3 or more.

[0069] From the viewpoint of obtaining a film with relatively excellent hiding power, the average thickness of the flaky particles is 10 nm to 1,000 nm, preferably 50 nm to 1,000 nm, more preferably 100 nm to 500 nm. The average thickness of the flaky particles is obtained by observing and photographing the cross section of a single flaky particle using an electron microscope such as a scanning electron microscope or a transmission electron microscope, measuring the minor axes of any seven points of the flaky particle in the image, and calculating the average value.

[0070] From the viewpoint of obtaining a film with relatively excellent hiding power, the aspect ratio of the flaky particles is 3 or more, preferably 5 or more, and more preferably 10 or more. The aspect ratio of the flaky particles is obtained by observing and photographing the cross section of one flaky particle using an electron microscope such as a scanning electron microscope or a transmission electron microscope, and dividing the major axis of the cross section of the flaky particle in the image obtained by photographing the image by the average thickness of the flaky particles.

[0071] The average thickness of the flaky particles can be reduced by, for example, reducing the thickness of the vapor-deposited layer of the aluminum-based vapor-deposited film in the method for producing the polyolefin-based resin (A) described below, or can be increased by, for example, increasing the thickness of the vapor-deposited layer of the aluminum-based vapor-deposited film. The aspect ratio of the flaky particles can be reduced by, for example, increasing the shear force applied to the resin during melt-kneading in the method for producing the polyolefin-based resin (A) described below, or can be increased by, for example, increasing the kneading speed or lowering the kneading temperature during melt-kneading.

[0072] From the viewpoint of obtaining a film with relatively excellent hiding power, the content of the aluminum atoms is 100 wtppm or more and 10,000 wtppm or less, preferably 300 wtppm or more and 5,000 wtppm or less, and more preferably 500 wtppm or more and 3,000 wtppm or less, based on the entire polyolefin resin composition (A).

[0073] The content of aluminum atoms can be calculated using the following formula (III). Aluminum atom content = Ta × {Da / (Ta·Da+Tcpp·Dcpp)} ×{Mvmcpp / (Mopp+Mvmcpp)} (III) Here, Ta is the thickness (cm) of the vapor-deposited layer of the aluminum-based vapor-deposited polyolefin-based film described below, Da is the density of aluminum (g / mL), Tcpp is the thickness (cm) of the polyolefin-based film described below, Dcpp is the density (g / mL) of the polyolefin-based resin composition (A), Mvmcpp is the blend amount (parts by mass) of the aluminum-based vapor-deposited polyolefin-based film, and Mopp is the blend amount (parts by mass) of the polyolefin-based film.

[0074] The polyolefin resin composition (A) according to this embodiment may contain aluminum atoms in a form other than the flaky particles, to the extent that the effect is not impaired. Examples of the form other than the flaky particles include spherical particles. The content of the aluminum atoms in a form other than the flaky particles can be, for example, 100 wtppm or less based on the entire polyolefin resin composition (A).

[0075] Examples of aluminum atoms contained in the polyolefin resin composition (A) include those derived from aluminum-based vapor-deposited films, aluminum foils, etc. Among these, the aluminum atoms are preferably derived from aluminum-based vapor-deposited films, from the viewpoint of obtaining a film with relatively excellent hiding properties. Examples of aluminum-based vapor-deposited films include aluminum vapor-deposited films and alumina vapor-deposited films. The aluminum-based vapor-deposited film is preferably an aluminum vapor-deposited film.

[0076] The aluminum-based vapor-deposited film is a laminated film composed of at least two layers. At least one of the at least two layers constituting the aluminum-based vapor-deposited film is an aluminum-based inorganic vapor-deposited layer containing aluminum atoms. Furthermore, at least one layer of the aluminum-based vapor-deposited film contains at least one resin selected from the group consisting of polyolefin-based resins, polyamide-based resins, and polyester-based resins. Furthermore, the polyolefin-based resin may be any of the above-mentioned polyolefin-based resins, or may be a polyolefin-based resin other than the above-mentioned polyolefin-based resins.

[0077] From the viewpoint of obtaining a film with relatively excellent hiding properties, the content of aluminum atoms contained in the aluminum-based inorganic vapor deposition layer is preferably 50 wt% or more, and more preferably 80 wtppm or more and 80 wt% or less, relative to the entire aluminum-based inorganic vapor deposition layer.

[0078] From the viewpoint of obtaining a film with relatively excellent hiding power, the thickness of the aluminum-based vapor-deposited film is preferably 20 μm or more and 300 μm or less, and more preferably 50 μm or more and 200 μm or less.

[0079] The thickness of the aluminum-based inorganic vapor deposition layer constituting the aluminum-based vapor deposition film is preferably 10 nm or more and 1,000 nm or less, more preferably 20 nm or more and 500 nm or less, from the viewpoint of obtaining a film with relatively excellent hiding properties.

[0080] The aluminum-based inorganic vapor deposition layer may contain, in addition to aluminum atoms, oxygen atoms, for example.

[0081] The aluminum-based inorganic vapor deposition layer is generally formed by a vacuum deposition method, a sputtering method, an ion plating method, etc. From the viewpoints of operability and economy, the aluminum-based inorganic vapor deposition layer is preferably formed by a vacuum deposition method.

[0082] The aluminum-based inorganic vapor deposition layer may be formed, for example, by subjecting one surface of the film to a corona discharge treatment and then vapor-depositing aluminum atoms onto the corona discharge-treated surface using a vacuum vapor deposition device.

[0083] [Other additives] The polyolefin resin composition (A) according to the present embodiment may contain other additives as needed, such as pigments, dyes, inorganic fillers, neutralizing agents, antioxidants, lubricants, copper inhibitors, antifogging agents, antistatic agents, processing stabilizers, UV absorbers, light stabilizers, nucleating agents, clarifying nucleating agents, processing aids, metal soaps, foaming agents, antibacterial agents, plasticizers, flame retardants, flame retardant aids, polyolefin crosslinking agents, polyolefin crosslinking aids, brightness enhancers, flowability modifiers, and crystallization retarders.

[0084] The polyolefin resin composition (A) according to this embodiment can be produced, for example, by melt-kneading the aluminum-based vapor-deposited film, the polyolefin-based film, and, if necessary, other additives. Examples of kneaders used for melt-kneading include single-screw extruders, twin-screw extruders, Banbury mixers, and heated rolls. The aluminum-based vapor-deposited film and the polyolefin-based film may be crushed before use, if necessary.

[0085] The melt-kneading temperature is preferably 160° C. or higher and 230° C. or lower, and the melt-kneading time is preferably 1 minute or higher and 15 minutes or lower. The melt-kneading of the components may be carried out simultaneously or sequentially.

[0086] The polyolefin resin composition (A) according to this embodiment preferably satisfies the following physical property (1). (1) For a film (A) having a thickness of 110 μm obtained by molding a polyolefin resin composition (A) under press conditions of a temperature of 230°C and a pressure of 5 MPa, the CIE1976L * a * b * a defined by the color space * The value is between -3.5 and 3.5, and b * The value is between -3.0 and 4.0 inclusive.

[0087] As used herein, L * , a *, and , b * are CIE1976L, respectively. * a * b * Lightness L defined in the color space * , chromaticity a * , chromaticity b * In addition, CIE1976L * a * b * In color space, a * is red direction, -a * is the green direction, b * is yellow direction, -b * indicates blue, and the smaller the value, the less color there is. * , a * , b * is measured by the SCE method using a spectrophotometer and calculated based on the standard of JIS Z 8729.

[0088] a in (1) above * value and b * The values ​​are those when the background color of film (A) is white. The white color here refers to the color obtained when two sheets of white neutral paper (Askul multi-paper Super White J A4, thickness 90 μm / sheet) are stacked together and used as the background.

[0089] The above a * From the viewpoint of obtaining a film having relatively excellent hiding power, the value of a is preferably −3.5 or more and 3.5 or less, more preferably −2.0 or more and 1.0 or less, and particularly preferably −1.5 or more and −1.0 or less. * The value can be decreased by increasing the amount of aluminum atoms, adding a green pigment, or the like, and can be increased by decreasing the amount of aluminum atoms, adding a red pigment, or the like.

[0090] The above b *From the viewpoint of obtaining a film having relatively excellent hiding power, the value of b is preferably −3.0 or more and 4.0 or less, more preferably −1.0 or more and 2.0 or less, and particularly preferably 0 or more and 1.5 or less. * The value can be decreased by increasing the amount of aluminum atoms, suppressing oxidation of the resin by lowering the processing temperature, adding a blue pigment, etc., and can be increased by decreasing the amount of aluminum atoms, promoting oxidation of the resin by raising the processing temperature, adding a yellow pigment, etc.

[0091] The polyolefin resin composition (A) according to this embodiment preferably satisfies the following physical property (2). (2) When the color difference between when the background color of the film is white and when it is black is ΔE, the following formula (I) holds true. 3≦(ΔE of film (B))-(ΔE of film (A))≦60 (I) Here, the film (B) is a film obtained by molding the polyolefin resin composition (B) under the same pressing conditions as in (1) above, and the polyolefin resin composition (B) does not contain aluminum atoms.

[0092] ΔE in (2) above is the colorimetric value (L1 * value,a1 * value,b1 * value) and the color measurement value when black (L2 * ,a2 * ,b2 * ) and is defined as the hiding power in this specification. ΔE={(L2 * -L1 * ) 2 +(a2 * -a1 * ) 2 +(b2 * -b1 * ) 2} 0.5 (II) The white color referred to here is the same as the white color described above, and the black color is the color obtained when black paper (A4 light black color paper, thickness 0.08 mm, manufactured by Nagatoya Shoten Co., Ltd.) is used as the background. The ΔE can be reduced by reducing the amount of aluminum atoms, and can be increased by increasing the amount of aluminum atoms or adding a pigment.

[0093] In the above (2), from the viewpoint of obtaining a film with relatively excellent hiding power, (ΔE of film (B)) - (ΔE of film (A)) is preferably 3 ≦ (ΔE of film (B)) - (ΔE of film (A)) ≦ 60, preferably 15 ≦ (ΔE of film (B)) - (ΔE of film (A)) ≦ 58, and more preferably 25 ≦ (ΔE of film (B)) - (ΔE of film (A)) ≦ 55.

[0094] The film (B) is a film obtained by molding a polyolefin resin composition (B) described below under the same press conditions as those in the above (1).

[0095] The polyolefin resin composition (B) contains a polyolefin resin and does not contain aluminum atoms. The polyolefin resin contained in the polyolefin resin composition (B) may be the same as the polyolefin resin (A).

[0096] In one aspect, the polyolefin resin composition (A) according to this embodiment satisfies the physical properties (1) and (2) above.

[0097] (film) <Film i> In one aspect, the film according to this embodiment is a film comprising a polyolefin resin composition (A) containing a polyolefin resin and aluminum atoms present in the form of flaky particles having an average thickness of 10 nm to 1,000 nm and an aspect ratio of 3 or more, the aluminum atoms being derived from an aluminum-based vapor-deposited film in an amount of 100 wtppm to 10,000 wtppm based on the total film. Hereinafter, this film will be referred to as film i.

[0098] Examples of the polyolefin resin contained in the polyolefin resin composition (A) include polyethylene resins, polypropylene resins, etc. Among these, the polyolefin resin is preferably at least one of polyethylene resins and polypropylene resins from the viewpoint of obtaining a film with relatively excellent hiding power. Note that the polyolefin resin may be the same polyolefin resin as the polyolefin resin composition (A) according to this embodiment.

[0099] The aluminum atom can be the same as that in the polyolefin resin composition (A) according to this embodiment.

[0100] As the aluminum-based vapor-deposited film, the same aluminum-based vapor-deposited film as that of the polyolefin-based resin composition (A) according to this embodiment can be used.

[0101] From the viewpoint of obtaining a film with relatively excellent hiding power, the content of aluminum atoms is 100 wtppm or more and 10,000 wtppm or less, preferably 300 wtppm or more and 5,000 wtppm or less, and more preferably 500 wtppm or more and 3,000 wtppm or less, relative to the entire film i.

[0102] The polyolefin resin composition (A) may be the polyolefin resin composition (A) according to the present embodiment described above.

[0103] From the viewpoint of obtaining a film with relatively excellent hiding power, the thickness of the film i is preferably 20 μm or more and 300 μm or less, and more preferably 50 μm or more and 200 μm or less.

[0104] The film i may be a single-layer film or a multi-layer film including at least one layer containing the polyolefin resin composition (A).

[0105] When film i is a single-layer film, it can be produced by, for example, inflation molding, T-die molding, calendar molding, blow molding, sheet molding, etc. When film i is a multilayer film, it can be produced by, for example, a multilayer film formation method such as coextrusion, extrusion lamination, thermal lamination, or dry lamination.

[0106] <Film II> In another aspect, the film according to the present embodiment is a film containing a resin composition obtained by mixing a polyolefin-based resin composition (A) and a polyolefin-based resin composition (B), The polyolefin resin composition (A) is the polyolefin resin composition (A) according to the present embodiment described above, The polyolefin resin composition (B) contains a polyolefin resin and does not contain aluminum atoms. Hereinafter, the film according to this embodiment will be referred to as film ii.

[0107] Examples of the polyolefin resin contained in the polyolefin resin composition (B) include polyethylene resins, polypropylene resins, etc. Among these, the polyolefin resin is preferably at least one of polyethylene resins and polypropylene resins from the viewpoint of obtaining a film with relatively excellent hiding power. The polyolefin resin may be the same polyolefin resin as the polyolefin resin composition (A) according to this embodiment.

[0108] The polyolefin resin composition (B) may be the polyolefin resin composition (B) described above.

[0109] In the resin composition contained in film ii, the ratio of the polyolefin resin composition (A) to the polyolefin resin composition (B) is preferably 20-80:80-20, more preferably 40-60:60-40, from the viewpoint of obtaining a film with relatively excellent hiding properties.

[0110] From the viewpoint of obtaining a film with relatively excellent hiding power, the thickness of film ii is preferably 20 μm or more and 300 μm or less, and more preferably 50 μm or more and 200 μm or less.

[0111] Film ii may be a single-layer film or a multi-layer film including at least one layer containing a resin composition obtained by mixing polyolefin-based resin composition (A) and polyolefin-based resin composition (B).

[0112] Film ii can be produced in the same manner as film i above.

[0113] <Film III> In yet another aspect, the film according to the present embodiment is a film in which a layer containing the polyolefin resin composition (A) and a layer containing the polyolefin resin composition (B) are laminated together, The polyolefin resin composition (A) is the polyolefin resin composition (A) according to the present embodiment, and the polyolefin resin composition (B) contains a polyolefin resin but does not contain aluminum atoms. Hereinafter, the film according to this embodiment will be referred to as film iii.

[0114] Examples of the polyolefin resin contained in the polyolefin resin composition (B) include polyethylene resins, polypropylene resins, etc. Among these, the polyolefin resin is preferably at least one of polyethylene resins and polypropylene resins from the viewpoint of obtaining a film with relatively excellent hiding power. The polyolefin resin may be the same polyolefin resin as the polyolefin resin composition (A) according to this embodiment.

[0115] The polyolefin resin composition (B) may be the polyolefin resin composition (B) described above.

[0116] From the viewpoint of obtaining a film with relatively excellent hiding power, the thickness of film iii is preferably 20 μm or more and 300 μm or less, and more preferably 50 μm or more and 200 μm or less.

[0117] The thickness of the layer containing the polyolefin resin composition (A) is preferably 20 μm or more and 300 μm or less, more preferably 50 μm or more and 200 μm or less, from the viewpoint of obtaining a film with relatively excellent hiding power.

[0118] The film iii may be a multilayer film including at least one layer containing the polyolefin resin composition (A) and at least one layer containing the polyolefin resin composition (B).

[0119] The film iii can be produced in the same manner as in the case where the film i is a multilayer film.

[0120] The film according to this embodiment may be subjected to a surface treatment such as corona discharge treatment, flame treatment, plasma treatment, or ozone treatment by a method generally employed industrially.

[0121] (packaging bag) The packaging bag according to this embodiment includes any one of the above films.

[0122] The packaging bag according to this embodiment may be in any known form, such as a pillow package, a three-side sealed package, a four-side sealed package, a gusset package, or a standing pouch.

[0123] The packaging bag according to this embodiment can be produced by a known method. For example, the film can be folded into a bag shape and heat-sealed to form a food packaging bag.

[0124] The packaging bag according to this embodiment is used for packaging any object to be packaged, such as food, clothing, miscellaneous goods, etc.

[0125] When the object to be packaged is food, the packaging bag according to this embodiment is suitable for packaging food such as candy, snacks, rice crackers, etc.

[0126] The polyolefin resin composition, film, and packaging bag according to the present embodiment are not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. In addition, the configurations, methods, etc. of embodiments other than those described above may be arbitrarily adopted and combined, and the configurations, methods, etc. of one embodiment described above may be applied to the configurations, methods, etc. of other embodiments described above.

[0127] The present invention includes the following aspects. [1] A polyolefin resin, aluminum atoms present in the form of flaky particles having an average thickness of 10 nm or more and 1,000 nm or less and an aspect ratio of 3 or more; A polyolefin resin composition (A) comprising: The polyolefin resin composition (A) has an aluminum atom content of 100 wtppm or more and 10,000 wtppm or less based on the entire polyolefin resin composition (A). [2] The polyolefin resin composition (A) according to [1], which satisfies the following physical properties (1) and (2): (1) For a film (A) having a thickness of 110 μm obtained by molding a polyolefin resin composition (A) under press conditions of a temperature of 230°C and a pressure of 5 MPa, the CIE1976L * a * b * a defined by the color space * The value is between -3.5 and 3.5, and b * The value is between -3.0 and 4.0 inclusive. (2) When the color difference between when the background color of the film is white and when it is black is ΔE, the following formula (I) holds true. 3≦(ΔE of film (B))-(ΔE of film (A))≦60 (I) Here, the film (B) is a film obtained by molding a polyolefin-based resin composition (B) containing a polyolefin-based resin under the same press conditions as in (1), and the polyolefin-based resin composition (B) does not contain aluminum atoms. [3] The polyolefin-based resin composition (A) according to [1] or [2], wherein the polyolefin-based resin contained in the polyolefin-based resin composition (A) is at least one of a polyethylene-based resin and a polypropylene-based resin. [4] The polyolefin resin composition (A) according to any one of [1] to [3], wherein the aluminum atoms contained in the polyolefin resin composition (A) are derived from an aluminum-based vapor-deposited film. [5] The polyolefin resin composition (A) according to [4], wherein the thickness of the aluminum-based inorganic vapor-deposited layer contained in the aluminum-based vapor-deposited film is 10 nm or more and 1,000 nm or less. [6] a polyolefin resin; aluminum atoms present in the form of flaky particles having an average thickness of 10 nm or more and 1,000 nm or less and an aspect ratio of 3 or more; A film comprising a polyolefin resin composition (A) comprising: The content of the aluminum atoms is 100 wtppm or more and 10,000 wtppm or less with respect to the entire film, The aluminum atoms are derived from an aluminum-based vapor-deposited film. [7] The film according to [6], wherein the polyolefin resin is at least one of a polyethylene resin and a polypropylene resin. [8] A film containing a resin composition obtained by mixing a polyolefin-based resin composition (A) and a polyolefin-based resin composition (B), The polyolefin resin composition (A) is the polyolefin resin composition (A) according to any one of [1] to [5], The polyolefin resin composition (B) is a film containing a polyolefin resin and not containing aluminum atoms. [9] A film in which a layer containing a polyolefin resin composition (A) and a layer containing a polyolefin resin composition (B) are laminated, The polyolefin resin composition (A) is the polyolefin resin composition (A) according to any one of [1] to [5], The polyolefin resin composition (B) is a film containing a polyolefin resin and not containing aluminum atoms.

[10] The film according to [8] or [9], wherein the polyolefin resin contained in the polyolefin resin composition (B) is at least one of a polyethylene resin and a polypropylene resin.

[11] A packaging bag comprising the film according to any one of [6] to

[10] . [Example]

[0128] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples. The measured values ​​of each item in the examples and comparative examples were measured by the following methods.

[0129] (Method of measuring physical properties) [Melt flow rate (MFR, unit: g / 10 min)] Measurement was performed using Method A in accordance with JIS K7210-1:2014 and K7210-2:2014 under conditions of a temperature of 230°C and a load of 2.16 kg.

[0130] [Film thickness (unit: μm)] The thickness was measured using a contact type film thickness meter according to Method A described in JIS K7130-1999.

[0131] [Tone (L) * ,a * ,b * )] CIE1976L * a * b * Based on the color space, a film sample described below was placed on a white background and measured using a colorimeter (spectro-guide 45 / 0 gloss manufactured by BYK-Gardner GmbH). For the white background, two sheets of white neutral paper (Askul multi-paper Super White J A4, thickness 90 μm / sheet) were used. * , a * , b * were 95.1, -0.7, and 0.75, respectively.

[0132] [Opacity (ΔE)] The film sample described below was measured in the same manner as the above color tone, and the color measurement value (L1 * ,a1 * ,b1 * ) and the color measurement value (L2 * ,a2 * ,b2 * ) was used to calculate using the following formula (II), and the color difference between the two points obtained was determined as the hiding power ΔE. ΔE={(L2 * -L1 * ) 2 +(a2 * -a1 * ) 2 +(b2 * -b1 * ) 2}0.5 (II) For the black background, black paper (A4 light black color paper manufactured by Nagatoya Shoten Co., Ltd., thickness 0.08 mm) was used. * , a * , b * were 26.2, 0.3, and 1.4, respectively.

[0133] [Density (unit: kg / m 3 )] Measurement was carried out in accordance with Method A described in JIS K7112-1980.

[0134] [Thickness of aluminum-based inorganic vapor deposition layer (unit: nm)] Pt-Pd vapor deposition (about 6 nm) was performed on the non-vapor-deposited side of an aluminum-based vapor-deposited polyolefin film described below, the resulting film was embedded in epoxy, and the resulting sample was cut using a microtome in a direction perpendicular to the film-forming direction to obtain a cross section of the sample. The cross section of the sample was then observed using a scanning electron microscope under the following observation conditions, and the thickness of the aluminum-based inorganic vapor-deposited layer on the sample was measured. Observation conditions Equipment used: Hitachi High-Tech Corporation HITACHI SU8020 Accelerating voltage: 3 kV Photography mode: Backscattered electron image by upper detector

[0135] [Average thickness of flaky particles (unit: nm)] For the films (A)-1 to (A)-5 of each example and the film (A')-1 of Comparative Example 1 described below, the samples were first observed using the same method as used to measure the thickness of the aluminum-based inorganic vapor deposition layer. Next, the samples were observed at a magnification of 10,000x. If flaky particles could be confirmed within the field of view, the magnification was increased to 18,000 to 70,000x so that the flaky particles fit within the field of view, and the cross-sections of the flaky particles were observed and photographed. If the flaky particles could not fit within the field of view at 10,000x magnification, the magnification was reduced to a minimum of 2,500x, and the cross-sections of the flaky particles were photographed so that the flaky particles fit within the field of view. Two fields of view were photographed for the sample.

[0136] In the images of the two fields of view obtained by the photographing, the minor axis was measured at seven arbitrary points per flaky particle using the two-point distance measurement function of the image analysis software "WinROOF2018" (manufactured by Mitani Shoji Co., Ltd.), and the average value was taken as the average thickness of the flaky particle. The thickness of all flaky particles included in the two fields of view was measured, and the results are shown in Table 2. In Table 2, N1 to N4 represent the respective flaky particles included in the two fields of view.

[0137] [Aspect ratio of flaky particles] In the images obtained by photographing the above-mentioned maximum thickness measurement of the flaky particles, the length from one end to the other end of each flaky particle (hereinafter referred to as the major axis) was measured using the polygon distance measurement function of the image analysis software "WinROOF2018" (Mitani Shoji Co., Ltd.). The aspect ratio of the flaky particles was calculated by dividing the obtained major axis by the average thickness of the flaky particles. The aspect ratios of all flaky particles contained in the two fields of view were measured, and the results are shown in Table 2. In Table 2, N1 to N4 refer to the flaky particles contained in the two fields of view.

[0138] [Aluminum foil thickness (unit: μm)] The thickness was measured using a contact type film thickness meter according to Method A described in JIS K7130-1999.

[0139] Example 1 [Production of propylene polymers] Propylene and ethylene were copolymerized in the gas phase in the presence of a Ziegler-Natta catalyst to obtain a powder of propylene-ethylene random copolymer with a melting point of 139°C and a melting rate of 6.0 g / 10 min measured at 230°C. The content of ethylene-derived monomer units in the propylene-ethylene random copolymer was 3.9% by mass, based on 100% by mass of the total mass of the copolymer. Hereinafter, the obtained propylene-ethylene random copolymer will be referred to as a propylene-based polymer.

[0140] [Production of Propylene-Based Polymer Composition] For 100 parts by mass of propylene polymer, 0.05 parts by mass of calcium stearate (neutralizer, manufactured by Kyodo Pharmaceutical Co., Ltd.), 0.175 parts by mass of IRGANOX 1010 (manufactured by BASF Japan Ltd.), 0.075 parts by mass of IRGANOX 3114 (manufactured by BASF Japan Ltd.), G1900 (high-density polyethylene, melt flow rate: 17.0 g / 10 min at 190°C, density: 0.956 g / cm 3 The resulting mixture was melt-extruded to obtain a pellet-shaped propylene polymer composition. The specific gravity of the propylene polymer composition was 0.9 g / mL.

[0141] [Preparation of undeposited polyolefin film] Using a T-die film-forming machine equipped with an extruder with a screw diameter of 50 mm, the propylene polymer composition was heated and melted at a resin temperature of 260°C and extruded onto a cooling roll at 50°C to form a film. One side of the obtained film was subjected to a corona discharge treatment to obtain an undeposited polyolefin film. The thickness of the undeposited polyolefin film was 30 μm.

[0142] [Preparation of aluminum-based vapor-deposited polyolefin film] Using a vacuum deposition apparatus (P-59 model manufactured by Sato Vacuum Machinery Co., Ltd.), aluminum was deposited on the corona discharge-treated surface of the undeposited polyolefin film to obtain an aluminum-based deposited polyolefin film. The thickness of the aluminum-based inorganic deposited layer was 430 angstroms (43 nm).

[0143] [Production of Polyolefin Resin Composition (A)-1] 30 parts by mass of aluminum-based vapor-deposited polyolefin-based film was mixed with 20 parts by mass of polyolefin-based film (biaxially oriented polypropylene film, product name: P2102, thickness 20 μm, manufactured by Toyobo Co., Ltd.), and the resulting mixture was melt-kneaded for 5 minutes using a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) under a nitrogen atmosphere at a set temperature of 230°C and a screw rotation speed of 60 rpm, to obtain polyolefin-based resin composition (A)-1. No abnormalities were observed during melt-kneading, and no phenomena such as the aluminum-based inorganic vapor-deposited layer concentrating and adhering to the screw of the Labo Plastomill were visually observed.

[0144] The aluminum atom content in the polyolefin resin composition (A)-1 was 2,600 wtppm. The aluminum atom content was calculated using the following formula (III), where the density of aluminum was 2.7 g / mL and the density of the polyolefin resin composition (A) was 0.9 g / mL. Aluminum atom content = Ta × {Da / (Ta·Da+Tcpp·Dcpp)} ×{Mvmcpp / (Mopp+Mvmcpp)} (III) where: Ta: Thickness of the aluminum-based vapor-deposited polyolefin film layer (cm) Da: density of aluminum (g / mL) Tcpp: Polyolefin film thickness (cm) Dcpp: density of polyolefin resin composition (A) (g / mL) Mvmcpp: Amount of aluminum-based vapor-deposited polyolefin film (parts by mass) Mopp: Polyolefin film blend amount (parts by mass) When film (A)-1 described below was observed using an electron microscope, almost all aluminum atoms were found to be in the form of flaky particles, and therefore the content of aluminum atoms in polyolefin resin composition (A)-1 corresponds to the content of aluminum atoms forming the flaky particles. The content of aluminum atoms and the blending ratios of each material used to produce polyolefin resin composition (A)-1 are shown in Table 1.

[0145] [Preparation of Film (A)-1] The polyolefin resin composition (A)-1 was pressure-molded at a temperature of 230°C and a pressure of 5 MPa to obtain a film (A)-1 having a thickness of 110 μm. Visual inspection of the appearance of the obtained film (A)-1 confirmed that the particles containing aluminum atoms contained in the film (A)-1 were uniformly dispersed. The color tone of the film (A)-1 was also measured using a colorimeter. The results are shown in Table 3.

[0146] Examples 2 to 5 [Production of Polyolefin Resin Compositions (A)-2 to -5] Polyolefin resin compositions (A)-2 to (A)-5 were obtained in the same manner as in Example 1, except that 75, 200, 450, or 950 parts by mass of a propylene polymer composition was added to and mixed with 30 parts by mass of an aluminum-based vapor-deposited polyolefin film and 20 parts by mass of a biaxially stretched polypropylene film. As in Example 1, no abnormalities were observed during melt-kneading, and no phenomena such as the aluminum-based inorganic vapor-deposited layer concentrating and adhering to the screw of the Labo Plastomill were visually observed.

[0147] The aluminum atom contents in polyolefin resin compositions (A)-2 to 5 and the blending ratios of the materials used in producing polyolefin resin compositions (A)-2 to 5 are shown in Table 1. The aluminum atom contents were calculated using the following formula (IV). As in Example 1, the density of aluminum was 2.7 g / mL, and the density of polyolefin resin composition (A) was 0.9 g / mL. Aluminum atom content = Ta × {Da / (Ta·Da+Tcpp·Dcpp)} ×{Mvmcpp / (Mopp+Mvmcpp+M')} (IV) where: Ta: Thickness of the aluminum-based vapor-deposited polyolefin film layer (cm) Da: density of aluminum (g / mL) Tcpp: Polyolefin film thickness (cm) Dcpp: density of polyolefin resin composition (A) (g / mL) Mvmcpp: Amount of aluminum-based vapor-deposited polyolefin film (parts by mass) Mopp: Polyolefin film blend amount (parts by mass) M': Amount of propylene polymer composition (parts by mass) When films (A)-2 to (A)-5 described below were observed using an electron microscope, it was found that, similar to film (A)-1, almost all of the aluminum atoms were in the form of flaky particles. Therefore, the content of aluminum atoms in polyolefin resin compositions (A)-2 to (A)-5 corresponds to the content of aluminum atoms forming the flaky particles, similar to the content of aluminum atoms in polyolefin resin composition (A)-1.

[0148] [Preparation of Films (A)-2 to 5] Films (A)-2 to 5 were also produced in the same manner as in Example 1. Visual inspection of the appearances of the resulting films (A)-2 to 5 confirmed that the particles containing aluminum atoms contained in the films (A)-2 to 5 were uniformly dispersed. The color tones of the films (A)-2 to 5 were also measured using a colorimeter. The results are shown in Table 3.

[0149] (Comparative Example 1) [Production of Polyolefin Resin Composition (A')-1] A polyolefin resin composition (A')-1 was obtained in the same manner as in Example 1, except that 4,950 parts by mass of a propylene polymer composition was added to and mixed with 30 parts by mass of an aluminum-based vapor-deposited polyolefin film and 20 parts by mass of a biaxially oriented polypropylene film. Using the formula (IV) above, no abnormalities were observed during melt-kneading, as in Example 1, and no visual observations were made of the aluminum-based inorganic vapor-deposited layer concentrating and adhering to the screw of the Labo Plastomill. Furthermore, when film (A')-1, described below, was observed using an electron microscope, it was found that, similar to film (A)-1, almost all of the aluminum atoms were in the form of flaky particles. Therefore, the content of aluminum atoms in polyolefin resin composition (A')-1 corresponds to the content of aluminum atoms forming the flaky particles, as with the content of aluminum atoms in polyolefin resin composition (A')-1. Table 1 shows the aluminum atom concentration contained in the polyolefin resin composition (A')-1 and the blending ratio of each material used to produce the polyolefin resin composition (A')-1.

[0150] [Preparation of Film (A')-1] Film (A')-1 was produced in the same manner as in Example 1. Visual inspection of the appearance of the obtained film (A')-1 confirmed that the particles containing aluminum atoms contained in the film (A')-1 were uniformly dispersed. Furthermore, the color tone of the film (A')-1 was measured using a colorimeter. The results are shown in Table 3.

[0151] (Comparative Examples 2 to 4) [Production of Polyolefin Resin Compositions (A')-2 to -4] Polyolefin resin compositions (A')-2 to (A')-4 were obtained in the same manner as in Example 1, except that 30 parts by mass of the undeposited polyolefin film and 20 parts by mass of the polyolefin film were further mixed with 30 parts by mass of aluminum foil (10 μm thick, sold by Daiwa Bussan Co., Ltd.) and 450, 4950, and 12450 parts by mass of a propylene polymer composition. It was confirmed that none of the polyolefin resin compositions (A')-2 to (A')-4 were sufficiently mixed, and the aluminum foil was attached to the screw of the Labo Plastomill. Furthermore, when the films (A')-2 to (A')-4 described below were observed using an electron microscope, the flaky particles could not be confirmed, and therefore the aluminum atom content in Table 1 is entered as "-". The blending ratios of the materials used to produce the polyolefin resin compositions (A')-2 to (A')-4 are shown in Table 1.

[0152] [Preparation of Films (A')-2 to 4] Films (A')-2 to 4 were also produced in the same manner as in Example 1. Visual inspection of the appearances of the resulting films (A')-2 to 4 confirmed that a portion of the aluminum foil remaining in the polyolefin resin compositions (A')-2 to 4 remained in each of the films (A')-2 to 4, and that light was transmitted through only a portion of the entire film. The color tones of the films (A')-2 to 4 were also measured using a colorimeter. The results are shown in Table 3. The results for the films (A')-2 to 4 were measured only in the light-transmitted portion of the entire film, and the values ​​obtained were used as reference values.

[0153] (Reference example) [Production of polyolefin resin composition (B)] A polyolefin resin composition (B) was obtained in the same manner as in Example 1, except that 100 parts by mass of the propylene polymer composition was used. As in Example 1, no abnormalities were observed during melt-kneading, and no phenomena such as the aluminum-based inorganic vapor deposition layer concentrating and adhering to the screw of the Labo Plastomill were visually confirmed. The blending ratios of the materials used to produce the polyolefin resin composition (B) are shown in Table 1.

[0154] [Preparation of film (B)] Film (B) was produced in the same manner as in Example 1. The appearance of the obtained film (B) was visually inspected and confirmed to be uniform. The color tone of the film (B) was also measured using a colorimeter. The results are shown in Table 3.

[0155] [Table 1]

[0156] [Table 2]

[0157] [Table 3]

[0158] From Tables 2 and 3, it was found that the films of the examples, which satisfied all of the constituent requirements of the present invention, were superior in formability and hiding power compared to the films of the comparative examples.

Claims

1. A polyolefin resin, aluminum atoms present in the form of flaky particles having an average thickness of 10 nm or more and 1,000 nm or less and an aspect ratio of 3 or more; A polyolefin resin composition (A) comprising: The polyolefin resin composition (A) has a content of aluminum atoms of 100 wtppm or more and 10,000 wtppm or less based on the entire polyolefin resin composition (A).

2. The polyolefin resin composition (A) according to claim 1, which satisfies the following physical properties (1) and (2): (1) For a film (A) having a thickness of 110 μm obtained by molding the polyolefin resin composition (A) under press conditions of a temperature of 230° C. and a pressure of 5 MPa, the CIE 1976L ＊ a ＊ b ＊ a defined by the color space ＊ The value is -3.5 or more and 3.5 or less, and b ＊ The value is between -3.0 and 4.

0. (2) When the color difference between when the background color of the film is white and when it is black is ΔE, the following formula (I) holds true. 3≦(ΔE of film (B))−(ΔE of film (A))≦60 (I) Here, the film (B) is a film obtained by molding a polyolefin-based resin composition (B) containing a polyolefin-based resin under the same press conditions as in (1) above, and the polyolefin-based resin composition (B) does not contain aluminum atoms.

3. The polyolefin-based resin composition (A) according to claim 1 or 2, wherein the polyolefin-based resin contained in the polyolefin-based resin composition (A) is at least one of a polyethylene-based resin and a polypropylene-based resin.

4. The polyolefin resin composition (A) according to claim 1 or 2, wherein the aluminum atoms contained in the polyolefin resin composition (A) are derived from an aluminum-based vapor-deposited film.

5. The polyolefin resin composition (A) according to claim 4, wherein the thickness of the aluminum-based inorganic vapor-deposited layer contained in the aluminum-based vapor-deposited film is 10 nm or more and 1,000 nm or less.

6. A polyolefin resin, aluminum atoms present in the form of flaky particles having an average thickness of 10 nm or more and 1,000 nm or less and an aspect ratio of 3 or more; A film comprising a polyolefin resin composition (A) comprising: the content of the aluminum atoms is 100 wtppm or more and 10,000 wtppm or less with respect to the entire film, The aluminum atoms are derived from an aluminum-based vapor-deposited film.

7. The film according to claim 6 , wherein the polyolefin resin is at least one of a polyethylene resin and a polypropylene resin.

8. A film containing a resin composition obtained by mixing a polyolefin-based resin composition (A) and a polyolefin-based resin composition (B), The polyolefin-based resin composition (A) is the polyolefin-based resin composition (A) according to claim 1, The polyolefin resin composition (B) of the film contains a polyolefin resin and does not contain aluminum atoms.

9. a film in which a layer containing the polyolefin resin composition (A) and a layer containing the polyolefin resin composition (B) are laminated together, The polyolefin-based resin composition (A) is the polyolefin-based resin composition (A) according to claim 1, The polyolefin resin composition (B) of the film contains a polyolefin resin and does not contain aluminum atoms.

10. The film according to claim 8 or 9, wherein the polyolefin resin contained in the polyolefin resin composition (B) is at least one of a polyethylene resin and a polypropylene resin.

11. A packaging bag comprising the film according to any one of claims 6 to 9.

12. A packaging bag comprising the film of claim 10.

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