Olefin polymer composition and film

Abstract

To provide an olefinic polymer composition enabling formation of a film which is heat sealable at comparatively low temperature, and has good anti-blocking property, and to provide a film containing the olefinic polymer composition.SOLUTION: The olefinic polymer composition contains an olefinic polymer, and satisfies the following requirements (1)-(3). Requirement (1): The elution amount measured at 70°C-95°C of the olefinic polymer composition using a gel permeation chromatograph comprising a graphite-packed column is 10.0 mass%-28.0 mass% with respect to 100 mass% of an elution amount measured at up to 160°C by a temperature gradient interaction chromatography. Requirement (2): The amount of cold xylene-soluble portion is 20.0 mass%. Requirement (3): The melting point is 150°C or lower.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an olefin-based polymer composition and a film containing the olefin-based polymer composition. [Background technology]

[0002] Multilayer films comprising a base film and a sealant film laminated on the base film are widely known as films used in various packaging materials. Specifically, films using various biaxially oriented films as the base film and polypropylene-based biaxially oriented films or unstretched films as the sealant film are known. Films with such configurations are widely used as materials for forming various packaging bags. When forming a packaging bag using such a film (performing a bag manufacturing process), the edges of the films are overlapped so that the sealant films face each other, and the edges are heated and heat-sealed to form the packaging bag. This allows for the formation of a sealed packaging bag.

[0003] In recent years, bag-making speeds have been increasing and heating times for heat sealing have been shortened, leading to a demand for materials that can form sealant films that can be heat-sealed at relatively low temperatures. For example, Patent Document 1 discloses that a sealant film made of a resin composition containing a propylene polymer and a specific ethylene-α-olefin copolymer has excellent low-temperature sealing properties. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-161840 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the sealant film that can be heat-sealed at a relatively low temperature is wound into a roll or stacked as a sheet, the films may become difficult to peel from each other or may have poor sliding properties against each other, which is called blocking. If such blocking occurs, it becomes difficult to smoothly process the film.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an olefin polymer composition that can form a heat-sealable film at a relatively low temperature and that has good blocking resistance in the film, and a film containing the olefin polymer composition. [Means for solving the problem]

[0007] The olefin polymer composition according to the present invention contains an olefin polymer and satisfies the following requirements (1) to (3). Requirement (1): In temperature gradient interaction chromatography of the olefin polymer composition measured using a gel permeation chromatograph equipped with a graphite-packed column, the elution amount measured at 70°C to 95°C is 10.0% by mass to 28.0% by mass relative to 100% by mass up to 160°C. Requirement (2): The amount of cold xylene solubles is 20.0% by mass or less. Requirement (3): The melting point is below 150°C.

[0008] The film according to the present invention contains the above-mentioned olefin polymer composition. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an olefin polymer composition that can form a heat-sealable film at a relatively low temperature and that has good blocking resistance in the film, and a film containing the olefin polymer composition. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the olefin polymer composition and film according to the embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0011] The olefin polymer composition according to the present embodiment contains an olefin polymer, and preferably contains at least two kinds of olefin polymers. Examples of the olefin polymer include a propylene polymer, an ethylene polymer, and an α-olefin polymer.

[0012] In this specification, the propylene polymer is a propylene homopolymer or a propylene copolymer containing 50% by mass or more of monomer units derived from propylene. The ethylene polymer is an ethylene homopolymer or an ethylene copolymer containing 50% by mass or more of monomer units derived from ethylene. The α-olefin polymer is an α-olefin homopolymer or an α-olefin copolymer containing 50% by mass or more of monomer units derived from α-olefin.

[0013] The olefin polymer composition according to this embodiment satisfies requirement (1). That is, in temperature gradient interaction chromatography of the olefin polymer composition measured using a gel permeation chromatograph equipped with a graphite-packed column, the elution amount measured at 70°C to 95°C is 10.0% by mass to 28.0% by mass relative to 100% by mass of the elution amount measured up to 160°C. By adjusting the elution amount measured at 70°C to 95°C to fall within the above range, the olefin polymer composition can be formed into a film that can be heat-sealed at a relatively low temperature. The elution amount of the olefin polymer composition measured at 70°C to 95°C is preferably 15.0% by mass to 28.0% by mass, and more preferably 20.0% by mass to 28.0% by mass.

[0014] In requirement (1), the olefin polymer composition preferably has an elution amount of 3.0% by mass to 7.0% by mass at 70°C to 75°C, and more preferably 3.0% by mass to 6.2% by mass. The olefin polymer composition preferably has an elution amount of 2.0% by mass to 18.0% by mass at 90°C to 95°C, and more preferably 4.0% by mass to 10.0% by mass. In one aspect, the olefin polymer composition according to this embodiment preferably has an elution amount of 3.0% by mass to 7.0% by mass at 70°C to 75°C and an elution amount of 2.0% by mass to 18.0% by mass at 90°C to 95°C.

[0015] The amount of elution from the olefin polymer composition can be adjusted to the above range by selecting the type of olefin polymer contained in the olefin polymer composition and controlling the composition ratio thereof within a predetermined range. The amount of elution from the olefin polymer composition within a predetermined temperature range can be determined by the method described in the Examples below.

[0016] The olefin polymer composition according to this embodiment satisfies requirement (2). That is, the amount of cold xylene solubles is 20.0% by mass or less. By adjusting the amount of cold xylene solubles in the above range, the olefin polymer composition can form a film having good blocking resistance. The amount of cold xylene solubles in the olefin polymer composition is preferably 8.0% by mass to 20.0% by mass, and more preferably 8.0% by mass to 16.0% by mass.

[0017] The amount of the cold xylene solubles in the olefin polymer composition can be adjusted to the above range by selecting the type of olefin polymer contained in the olefin polymer composition and controlling the composition ratio thereof within a predetermined range. The amount of the cold xylene solubles can be determined by the method described in the examples below.

[0018] The olefin polymer composition according to this embodiment satisfies requirement (3). That is, the melting point is 150°C or less. By adjusting the melting point of the olefin polymer composition to fall within the above range, it is possible to form a film that can be heat-sealed at a relatively low temperature. The melting point of the olefin polymer composition is preferably 110°C to 150°C, and more preferably 110°C to 135°C.

[0019] The melting point of the olefin polymer composition can be adjusted to the above range by selecting the type of olefin polymer contained in the olefin polymer composition and controlling the composition ratio thereof within a predetermined range. The melting point of the olefin polymer composition can be determined by the method described in the examples below.

[0020] From the viewpoint of improving the low-temperature heat sealability and blocking resistance of the film, the olefin polymer composition according to this embodiment preferably contains, as one aspect, a propylene-ethylene copolymer (A) containing monomer units derived from propylene and monomer units derived from ethylene, a propylene-α-olefin copolymer (B) containing monomer units derived from propylene and monomer units derived from an α-olefin having 4 to 12 carbon atoms, an ethylene-α-olefin copolymer containing monomer units derived from ethylene and monomer units derived from an α-olefin having 4 to 12 carbon atoms, and at least one polymer (C) selected from the group consisting of α-olefin polymers containing 50% by mass or more of monomer units derived from an α-olefin having 4 to 12 carbon atoms.

[0021] The propylene-ethylene copolymer (A) is a propylene-based copolymer containing 50% by mass or more of monomer units derived from propylene. The content of the monomer units derived from propylene in the propylene-ethylene copolymer (A) is preferably 90% by mass to 99% by mass, more preferably 95% by mass to 99% by mass. The content of the monomer units derived from ethylene in the propylene-ethylene copolymer (A) is preferably 1% by mass to 10% by mass, more preferably 1% by mass to 5% by mass.

[0022] The propylene-α-olefin copolymer (B) is a propylene-based copolymer containing 50% by mass or more of monomer units derived from propylene. The content of the monomer units derived from propylene in the propylene-α-olefin copolymer (B) is preferably 70% by mass to 99% by mass, more preferably 75% by mass to 99% by mass. The content of the monomer units derived from an α-olefin having 4 to 12 carbon atoms in the propylene-α-olefin copolymer (B) is preferably 1% by mass to 30% by mass, more preferably 1% by mass to 25% by mass. Examples of the α-olefin having 4 to 12 carbon atoms include 1-butene, 1-hexene, and 1-octene, and 1-butene is preferred. When the α-olefin having 4 to 12 carbon atoms is 1-butene, the propylene-α-olefin copolymer (B) preferably contains 3% by mass to 30% by mass of monomer units derived from 1-butene.

[0023] The olefin polymer composition according to the present embodiment is not limited to a composition containing the propylene-ethylene copolymer (A) and the propylene-α-olefin copolymer (B) as the propylene polymer, and may contain other propylene polymers. In addition, in the olefin polymer composition, one type of propylene polymer may be used alone, or two or more types may be used in combination.

[0024] The melt flow rate (MFR) of the propylene polymer measured at a temperature of 230°C under a load of 2.16 kg is preferably 0.001 g / 10 min to 10 g / 10 min, more preferably 0.01 g / 10 min to 10 g / 10 min, and even more preferably 0.01 g / 10 min to 5 g / 10 min, from the viewpoint of improving the processability and hygienic properties of the film. The MFR is measured according to Method A specified in JIS K7210-1.

[0025] Examples of methods for producing propylene polymers include homopolymerization of propylene in the presence of a Ziegler-Natta catalyst, a metallocene catalyst, or the like, and copolymerization of propylene with an olefin other than propylene. Examples of Ziegler-Natta catalysts include catalysts that use a combination of a titanium-containing solid transition metal component and an organometallic component. Examples of metallocene catalysts include catalysts that use a combination of a transition metal compound of Groups 4 to 6 of the periodic table having at least one cyclopentadienyl skeleton and a cocatalyst component.

[0026] Examples of polymerization methods for propylene-based polymers include a method of polymerizing in an inert solvent such as hexane, heptane, toluene, or xylene, a method of polymerizing in liquid propylene or ethylene, a method of polymerizing in a gas phase by adding a catalyst to gaseous propylene or ethylene, or a method of polymerizing in a combination of these.

[0027] From the viewpoint of improving productivity, a method of carrying out a plurality of polymerization steps in multiple stages (multistage polymerization method) can be used as a method for polymerizing a propylene-based polymer. The multistage polymer obtained by such a multistage polymerization method may contain at least two types of propylene-based polymers, or may contain one type of propylene-based polymer. Therefore, when the multistage polymerization method is used as a method for polymerizing a propylene-based polymer, the propylene-based polymer contained in the olefin-based polymer composition according to this embodiment may constitute a multistage polymer. In other words, the olefin-based polymer composition according to this embodiment may contain a multistage polymer.

[0028] The multistage polymer is preferably a propylene-based multistage polymer composed of a propylene-ethylene copolymer (A) and a propylene-α-olefin copolymer (B). Such a propylene-based multistage polymer can be produced by carrying out a first step of polymerizing propylene and ethylene substantially in the absence of an inert solvent to produce a propylene-ethylene copolymer (A), and then carrying out a second step of polymerizing propylene and an α-olefin having 4 to 12 carbon atoms in a gas phase in the presence of the propylene-ethylene copolymer (A) to produce a propylene-α-olefin copolymer (B).

[0029] The content of the propylene-ethylene copolymer (A) is preferably 1% by mass to 80% by mass, more preferably 1% by mass to 50% by mass, relative to 100% by mass of the propylene-based multistage polymer. The content of the propylene-α-olefin copolymer (B) is preferably 20% by mass to 99% by mass, more preferably 50% by mass to 99% by mass, relative to 100% by mass of the propylene-based multistage polymer.

[0030] Methods for adjusting the ethylene or α-olefin content in the propylene-ethylene copolymer (A) and the propylene-α-olefin copolymer (B) include adding an appropriate amount of a molecular weight regulator such as hydrogen gas or a metal compound, and an appropriate amount of ethylene or α-olefin, in each step of the polymerization, and adjusting the temperature, pressure, etc. during the polymerization.

[0031] The production ratio of the propylene-ethylene copolymer (A) and the propylene-α-olefin copolymer (B) can be controlled by the polymerization time in the first and second steps, the size of the polymerization vessel, the amount of polymer held in the polymerization vessel, the polymerization temperature, the polymerization pressure, etc. If necessary, drying may be carried out at a temperature below the melting point of the polypropylene to remove residual solvent in the polypropylene and ultralow molecular weight oligomers produced as by-products during production. Examples of drying methods include those described in JP-A-55-75410 and JP-A-2565753.

[0032] In the polymer (C), the ethylene-α-olefin copolymer containing monomer units derived from ethylene and monomer units derived from an α-olefin having 4 to 12 carbon atoms is an ethylene-based copolymer containing 50% by mass or more of monomer units derived from ethylene.

[0033] The content of monomer units derived from ethylene in the ethylene-α-olefin copolymer is preferably 70% by mass to 95% by mass, more preferably 75% by mass to 95% by mass, and even more preferably 80% by mass to 95% by mass. The content of monomer units derived from α-olefin in the ethylene-α-olefin copolymer is preferably 5% by mass to 30% by mass, more preferably 5% by mass to 25% by mass, and even more preferably 5% by mass to 20% by mass.

[0034] In polymer (C), the α-olefin polymer containing 50% by mass or more of monomer units derived from an α-olefin having 4 to 12 carbon atoms is an α-olefin homopolymer or an α-olefin copolymer containing 50% by mass or more of monomer units derived from an α-olefin having 4 to 12 carbon atoms. Examples of the monomer units other than the α-olefin having 4 to 12 carbon atoms contained in the α-olefin copolymer include ethylene and propylene.

[0035] The content of the monomer units derived from the α-olefin having 4 to 12 carbon atoms in the α-olefin copolymer is preferably 60% by mass to 100% by mass, and more preferably 75% by mass to 100% by mass.

[0036] Examples of the α-olefin having 4 to 12 carbon atoms in the polymer (C) include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 4-methyl-1-pentene, and 4-methyl-1-hexene. The monomer units derived from the α-olefin having 4 to 12 carbon atoms may be monomer units derived from a single type of α-olefin, or may be monomer units derived from two or more types of α-olefins. From the viewpoint of improving heat seal strength, the α-olefin having 4 to 12 carbon atoms is preferably 1-hexene.

[0037] The polymer (C) is preferably an ethylene-α-olefin copolymer containing monomer units derived from ethylene and monomer units derived from an α-olefin having 4 to 6 carbon atoms. The polymer (C) is also preferably a homopolymer of an α-olefin having 4 to 6 carbon atoms.

[0038] The olefin polymer composition according to this embodiment is not limited to a composition containing an ethylene-α-olefin copolymer containing, as the ethylene polymer, monomer units derived from ethylene and monomer units derived from an α-olefin having 4 to 12 carbon atoms, and may contain other ethylene polymers. Furthermore, the olefin polymer composition according to this embodiment is not limited to a composition containing, as the α-olefin polymer, an α-olefin polymer containing 50% by mass or more of monomer units derived from an α-olefin having 4 to 12 carbon atoms, and may contain other α-olefin polymers.

[0039] The density of the polymer (C) is preferably 850 kg / m 3 ~950kg / m 3 and more preferably 850 kg / m 3 ~930kg / m 3 and more preferably 880 kg / m 3 ~930kg / m 3 The density of the polymer (C) is 850 kg / m 3 By satisfying the above conditions, a film excellent in terms of rigidity can be obtained, and the film strength is 950 kg / m3 By satisfying the following conditions, a film having excellent impact resistance at low temperatures can be obtained.

[0040] The polymer (C) preferably has a melt flow rate (MFR) measured at a temperature of 190°C under a load of 2.16 kg of 0.1 g / 10 min to 50 g / 10 min, more preferably 0.1 g / 10 min to 10 g / 10 min, and even more preferably 1 g / 10 min to 5 g / 10 min. The MFR is measured according to Method A specified in JIS K7210-1.

[0041] The molecular weight distribution of polymer (C) is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, and even more preferably 2 or more and 4 or less. When the molecular weight distribution of polymer (C) is 1 or more, the extrusion load is reduced and processability is improved. Furthermore, when the molecular weight distribution of polymer (C) is 5 or less, a film with excellent impact resistance at low temperatures can be obtained. Here, the "molecular weight distribution" refers to the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by gel permeation chromatography (hereinafter sometimes referred to as "GPC").

[0042] As a method for adjusting the molecular weight distribution of the polymer (C) to the above range, for example, a metallocene catalyst may be used to copolymerize ethylene with an α-olefin having 4 to 12 carbon atoms, or an α-olefin having 4 to 12 carbon atoms with another olefin, or to homopolymerize an α-olefin, to adjust the density of the polymer (C) to 850 kg / m 3 ~950kg / m 3 The following method can be mentioned.

[0043] The polymer (C) can be produced, for example, using a metallocene catalyst, such as a catalyst for olefin polymerization that uses a transition metal compound having a group with a cyclopentadiene-type anion skeleton (hereinafter, sometimes referred to as a "metallocene-based transition metal compound").

[0044] Examples of the metallocene transition metal compound include a compound represented by the formula MLaXn-a (where M is a transition metal atom of Group 4 of the periodic table of elements or a lanthanide series, L is a group having a cyclopentadiene-shaped anion skeleton or a group containing a hetero atom, at least one of which is a group having a cyclopentadiene-shaped anion skeleton, and a plurality of Ls may be crosslinked to each other, X is a halogen atom, a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, n represents the valence of the transition metal atom, and a is an integer satisfying 0 < a ≤ n).

[0045] Examples of the metallocene transition metal compound represented by the above formula include bis(1,3-n-butylmethylcyclopentadienyl)zirconium dichloride, bis(1,3-n-propylmethylcyclopentadienyl)zirconium dichloride, bis(n-butylcyclopentadienyl)zirconium dichloride, bis(1,3-dimethylcyclopentadienyl)zirconium dichloride, bis(1,3-diethylcyclopentadienyl)zirconium dichloride, ethylenebis(indenyl)zirconium dichloride, ethylenebis(4-methyl-1-indenyl)zirconium dichloride, ethylenebis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride, and the like.

[0046] The above metallocene transition metal compound is preferably used in contact with an activating cocatalyst. Examples of the activating cocatalyst include an aluminoxane compound, and an activating cocatalyst obtained by using an organoaluminum compound in combination with a boron compound such as trityl borate or anilinium borate. Further, it may be used in combination with a particulate carrier containing an inorganic carrier such as SiO2 or Al2O3, or an organic carrier such as a polymer of ethylene, styrene or the like.

[0047] The olefin polymer composition according to the present embodiment preferably further contains a monomer unit derived from ethylene and an ethylene-based polymer (D) having a density of 940 kg / m 3 ~970 kg / m 3 and is contained.

[0048] The ethylene polymer (D) is an ethylene homopolymer or an ethylene copolymer containing 50% by mass or more of monomer units derived from ethylene, and is preferably an ethylene homopolymer. The content of the monomer units derived from ethylene in the ethylene copolymer is preferably 70% by mass to 95% by mass, more preferably 75% by mass to 95% by mass, and even more preferably 80% by mass to 95% by mass.

[0049] The density of the ethylene polymer (D) is 940 kg / m from the viewpoint of improving blocking resistance and transparency. 3 ~970kg / m 3 and preferably 940 kg / m 3 ~960kg / m 3 and more preferably 950 kg / m 3 ~960kg / m 3 be.

[0050] The ethylene polymer (D) preferably has a melt flow rate (MFR) measured at a temperature of 190°C under a load of 2.16 kg of 0.1 g / 10 min to 50 g / 10 min, more preferably 0.1 g / 10 min to 10 g / 10 min, and even more preferably 1 g / 10 min to 5 g / 10 min. The MFR is measured according to Method A specified in JIS K7210-1.

[0051] The molecular weight distribution of the ethylene polymer (D) is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, and even more preferably 2 or more and 4 or less. When the ethylene polymer (D) has a molecular weight distribution of 1 or more, the extrusion load is reduced, resulting in good processability. Furthermore, when the ethylene copolymer (D) has a molecular weight distribution of 5 or less, a film with excellent impact resistance at low temperatures can be obtained. Here, the "molecular weight distribution" refers to the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), measured under the following conditions using gel permeation chromatography (hereinafter sometimes referred to as "GPC"). The baseline on the chromatogram was defined as a straight line connecting the points in a stable, flat region with a retention time sufficiently shorter than that at which the sample elution peak appears and the points in a stable, flat region with a retention time sufficiently longer than that at which the solvent elution peak is observed. Apparatus: Waters 150C Separation column: TOSOH TSK-GEL GMH6-HT Measurement temperature: 140℃ Carrier: Orthodichlorobenzene Flow rate: 1.0mL / min Injection volume: 500μL Detector: Differential refraction Molecular weight standards: Standard polystyrene

[0052] As a method for adjusting the molecular weight distribution of the ethylene polymer (D) to the above range, for example, a method for adjusting the density of the ethylene polymer (D) to 940 kg / m or more by homopolymerizing ethylene or copolymerizing ethylene with an olefin other than ethylene using a metallocene catalyst is used. 3 ~970kg / m 3 The following method can be mentioned.

[0053] Examples of methods for producing the ethylene polymer (D) include polymerization methods using a Ziegler-Natta catalyst, such as solution polymerization, slurry polymerization, and gas phase polymerization. Examples of Ziegler-Natta catalysts include catalysts comprising a solid catalyst component for olefin polymerization containing a titanium atom, a magnesium atom, or a halogen atom, and an organometallic compound. More specifically, the catalysts described in JP-A-11-322833 are included.

[0054] The content of the propylene copolymer (A) is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 20% by mass, based on 100% by mass of the olefin polymer composition. The content of the propylene copolymer (B) is preferably 50% by mass to 95% by mass, more preferably 50% by mass to 75% by mass, based on 100% by mass of the olefin polymer composition. The content of the polymer (C) is preferably 2% by mass to 40% by mass, more preferably 5% by mass to 30% by mass, based on 100% by mass of the olefin polymer composition. The content of the ethylene polymer (D) is preferably 0.1% by mass to 10% by mass, more preferably 1% by mass to 8% by mass, based on 100% by mass of the olefin polymer composition.

[0055] The olefin polymer composition according to this embodiment may contain additives or other resins as needed. Examples of additives include antioxidants, neutralizing agents, UV absorbers, antistatic agents, lubricants, nucleating agents, adhesives, antifogging agents, antiblocking agents, and melt flow rate modifiers. Examples of antioxidants include phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. Hybrid antioxidants containing units that combine both phenolic and phosphorus-based antioxidant mechanisms in a single molecule can also be used. Other resins include elastomers such as styrene-based copolymer rubbers obtained by hydrogenating styrene-butadiene-styrene copolymers and styrene-isoprene-styrene copolymers.

[0056] As one aspect, the olefin polymer composition according to the present embodiment preferably contains a propylene polymer material (I) containing at least one propylene polymer and having a melting point of more than 120°C, and an olefin polymer material (II) containing at least one olefin polymer and having a melting point of 120°C or lower.

[0057] The propylene polymer material (I) may be a material containing a multistage propylene polymer composed of a propylene copolymer (A) and a propylene copolymer (B). The melting point of the propylene polymer material (I) is above 120°C, preferably 121°C to 150°C, more preferably 121°C to 140°C.

[0058] The olefin polymer material (II) may be a material containing a polymer (C). The melting point of the olefin polymer material (II) is 120° C. or lower, preferably 80° C. to 120° C., and more preferably 80° C. to 115° C. The melting point of the olefin polymer material (II) in the range of 120° C. or lower may include cases where no melting point is observed.

[0059] The propylene polymer material (I) and the olefin polymer material (II) may contain the above-mentioned additives and other resins.

[0060] The film according to this embodiment contains the above-mentioned olefin polymer composition.

[0061] The film according to this embodiment has a Young's modulus in the MD direction of preferably 400 MPa to 500 MPa, more preferably 420 MPa to 480 MPa. The Young's modulus in the MD direction of the film can be determined by the method described in the examples below.

[0062] The film according to this embodiment can be formed, for example, by melt-kneading the propylene copolymer (A), the propylene copolymer (B), the polymer (C), and, if necessary, the ethylene polymer (D) and various additives.

[0063] The melt-kneading method can be carried out using a conventionally known method and apparatus. For example, the above materials are mixed using a mixing apparatus such as a Henschel mixer, a ribbon blender, or a tumble mixer, and then melt-kneaded. Alternatively, the above materials are continuously fed at a constant rate using a constant feeder to obtain a homogeneous mixture, and then the mixture is melt-kneaded using a single-screw or twin-screw or more extruder, a Banbury mixer, a roll kneader, or the like.

[0064] The melt-kneading temperature is preferably 190°C to 320°C, and more preferably 210°C to 280°C.

[0065] The film thus formed can be used as a sealant film. The film according to the present embodiment may be laminated with other films such as a substrate film to form a multilayer film. Examples of the substrate film include films made of biaxially oriented polyester resins, biaxially oriented polyamide resins, biaxial polyolefin resins, etc.

[0066] The multilayer film can be produced by known film production methods such as the T-die method and the tubular method, with the T-die method being preferred.

[0067] Methods for laminating each film include a method using a feedblock die, in which molten resin flowing into the die from multiple extruders is combined in layers within the die, and a method using a multi-manifold die, in which molten resin flowing into the die from multiple extruders is sent to separate manifolds and combined in layers just before the lip of the die.

[0068] The thickness of the film according to this embodiment is preferably 10 μm to 100 μm, and more preferably 10 μm to 50 μm.

[0069] When the film according to this embodiment is used as a sealant film and laminated with a base film to form a multilayer film, the thickness of the sealant film is preferably 10% to 30%, more preferably 15% to 30%, and even more preferably 15% to 25%, of the thickness of the multilayer film (defined as 100%). Furthermore, the thickness of the base film is preferably 70% to 90%, more preferably 70% to 85%, and even more preferably 75% to 85%, of the thickness of the multilayer film (defined as 100%). Having the thicknesses of the sealant film and base film within the above ranges makes it difficult for peeling to occur between the base film and the sealant film, resulting in a multilayer film with excellent heat seal strength and bag drop strength, and also suppressing the occurrence of unevenness (orange peel) on the surface of the multilayer film when heated.

[0070] The thickness of the multilayer film is preferably 5 μm to 500 μm, and more preferably 30 μm to 150 μm.

[0071] The multilayer film can be used for packaging (specifically, for packaging heavy items), for example, for packaging food, textiles, miscellaneous goods, etc. Preferably, the multilayer film is used for packaging retort food. The multilayer film may also be used as a material for forming packaging bags.

[0072] The olefin polymer composition and film according to this 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. [Example]

[0073] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to these examples.

[0074] The measured values ​​of each item in the examples and comparative examples were measured by the following methods.

[0075] (1) Temperature Gradient Interaction Chromatography 40 mg of the composition was added to 20 ml of orthodichlorobenzene containing 0.05% by mass of BHT, followed by heating and stirring at 150°C for 60 minutes to obtain a sample solution with a concentration of 2.0 mg / ml. 0.5 ml of the resulting sample solution was injected into a graphite-packed column (Thermo Fisher Scientific Hypercurve Column, high temperature, 10 mm inner diameter x 50 mm length, 35005-059046) maintained at 150°C in a CFC apparatus (cross-fractionation chromatograph, PolymerChart Automated 3D analyzer CFC-2) and held for 10 minutes. The sample solution was then cooled to 30°C at a rate of 40°C / min and held at 30°C for 30 minutes. The elution volume of the sample solution at 30°C was then measured using a gel permeation chromatograph (GPC) (Tosoh TSKgel GMHHR-H(S)HT, three tubes) equipped with an infrared spectrophotometer built into the CFC system. The sample solution was then heated to 35°C at a rate of 40°C / min and held at that temperature for approximately 36 minutes. The elution volume of the sample solution at 35°C was then measured using a GPC equipped with an infrared spectrophotometer built into the CFC system. As in the previous procedure, the sample solution was then heated to 160°C in 5°C increments at a rate of 40°C / min and held at that temperature. The elution volume of the sample solution at each temperature was then measured using a GPC equipped with an infrared spectrophotometer built into the CFC system. For the GPC measurements, an octyldichlorobenzene solution containing 0.05% by mass of BHT was used as the mobile phase, and the flow rate of the mobile phase was 1.0 mL / min.

[0076] (2) Cold xylene solubles (unit: mass%) 0.1 g to 1 g of the composition was mixed with 100 ml of xylene, and the resulting mixture was boiled and then refluxed for 30 minutes to dissolve the composition. The resulting solution was cooled in ice water for 20 minutes and then stirred for 1 hour while maintaining the temperature at 20°C. The resulting mixture was filtered through No. 50 filter paper. The filtrate was analyzed using liquid chromatography to measure the cold xylene-soluble portion of the composition. Column: SHODEX GPC KF-801 Eluent: tetrahydrofuran Column oven temperature: 40°C Sample injection volume: 130 μL Flow rate: 1mL / min Detector: differential refractometer

[0077] (3) Melting point Using a differential scanning calorimeter (Discovery DSC 250 manufactured by TA Instruments), approximately 5 mg of the composition was melted at 230°C under a nitrogen gas atmosphere (nitrogen gas flow rate 50 ml / min), held for 5 minutes, and cooled to 0°C at a rate of 5°C / min. Next, the composition was held at 0°C for 5 minutes, heated at a rate of 5°C / min, and measured up to 230°C. The temperature of the maximum peak of the obtained melting endothermic curve was taken as the melting temperature (Tm). Using the same differential scanning calorimeter, approximately 5 mg of indium (In) was held at 110°C for 2 minutes under a nitrogen gas atmosphere (nitrogen gas flow rate 50 ml / min), and then heated at a rate of 5°C / min up to 180°C.The temperature of the maximum peak of the obtained melting endothermic curve was measured as the melting temperature (Tm), which was 156.6°C.

[0078] (4) Content of monomer units derived from ethylene (unit: mass%) It was determined by the IR spectrum measurement method described on page 256 of Polymer Analysis Handbook (published by Asakura Publishing, 1985).

[0079] (5) Content of monomer units derived from α-olefins having 4 to 12 carbon atoms (unit: mass%) It was determined by the IR spectrum measurement method described on page 619 of Polymer Analysis Handbook (published by Kinokuniya Shoten in 1995).

[0080] (6) Ratio of propylene-ethylene copolymer (A) to propylene-α-olefin copolymer (B) (unit: mass%) It was determined by material balance in each step during polymerization.

[0081] (7) Melt flow rate (unit: g / 10 min) The MFR of propylene polymers and propylene polymer materials was measured at a temperature of 230°C and a load of 2.16 kg according to Method A of JIS K7210-1. The MFR of ethylene polymers and α-olefin polymers was measured at a temperature of 190°C and a load of 2.16 kg according to Method A of JIS K7210-1.

[0082] (8) Minimum sealable temperature (unit: °C) After overlapping the two films, a heat sealer manufactured by Toyo Seiki Co., Ltd. was used to seal the film at a specified temperature and 1 kg / cm. 2 The heat-sealed sample was then held at a temperature of 23°C and humidity of 50% for 24 hours, and then the sealing temperature at which the peel resistance reached 300 g / 15 mm when peeled using a tensile tester at a temperature of 23°C, humidity of 50%, a peel speed of 200 mm / min, and a peel angle of 180° was determined, and this was taken as the minimum temperature at which sealing was possible.

[0083] (9) Blocking strength (unit: N / 12cm 2 ) After the two films were placed face-to-face, a 40mm x 30mm weight with a weight of 500g was placed on top of them, and then the samples were heat-treated in an oven at 60°C for 24 hours. The heat-treated samples were left at a temperature of 23°C and a humidity of 50% for at least 30 minutes, after which the shear peel strength was measured at a pulling rate of 200mm / min using a tensile tester, and this was taken as the blocking strength.

[0084] (10) Young's modulus (unit: MPa) Test pieces 120 mm long (MD) and 20 mm wide (TD) were cut from the film. The test pieces were subjected to a benchtop tensile test using an A&D Co., Ltd. benchtop tensile tester with a chuck spacing of 60 mm and a tensile speed of 5 mm / min to obtain stress-strain curves and measure the initial elastic modulus (Young's modulus).

[0085] The components used in the examples and comparative examples are as follows.

[0086] [Propylene-based polymer materials (1)] Using a Ziegler-Natta catalyst, propylene and ethylene were copolymerized in the liquid phase in the first step, followed by copolymerization of propylene and 1-butene in the gas phase in the second step, resulting in a propylene-based multistage polymer consisting of a propylene-ethylene copolymer (A-1) and a propylene-1-butene copolymer (B-1). The propylene-ethylene copolymer (A-1) contained 4% by mass of ethylene-derived monomer units, and the propylene-1-butene copolymer (B-1) contained 25% by mass of 1-butene-derived monomer units. The resulting propylene-based multistage polymer contained 19% by mass of propylene-ethylene copolymer (A-1) and 81% by mass of propylene-1-butene copolymer (B-1). 100 parts by mass of the obtained propylene-based multistage polymer was mixed with 0.01 part by mass of hydrotalcite (Kyowa Chemical Industry Co., Ltd.), 0.15 part by mass of Irganox 1010 (BASF), and 0.03 part by mass of Sumilizer GP (Sumitomo Chemical Co., Ltd.), and then melt-kneaded to obtain a propylene-based polymer material (1) having a melt flow rate of 7 g / 10 min measured at 230°C. The melting point of the propylene-based polymer material (1) was 130.1°C.

[0087] [Propylene-based polymer materials (2)] Using a Ziegler-Natta catalyst, propylene and ethylene were copolymerized in the liquid phase in the first step, followed by copolymerization in the gas phase in the second step to obtain propylene-ethylene copolymer (A-2). The content of ethylene-derived monomer units in propylene-ethylene copolymer (A-2) was 4% by mass. 100 parts by mass of the resulting propylene-ethylene copolymer (A-2) was mixed with 0.045 parts by mass of calcium stearate (Sakai Chemical Industry Co., Ltd.), 0.2 parts by mass of Irganox 1010 (BASF), and 0.03 parts by mass of Irgafos 168 (BASF), followed by melt-kneading to obtain propylene-based polymer material (2). The melting point of propylene-based polymer material (2) was 142.0°C.

[0088] [Ethylene-α-olefin copolymer (C-1)] Sumikathene E FV401 (trade name) (manufactured by Sumitomo Chemical Co., Ltd.), an ethylene-1-hexene copolymer, was used. The content of ethylene-derived monomer units in Sumikathene E FV401 was 88% by mass. The melt flow rate measured at 190°C was 3.8 g / 10 min, and the density was 903 kg / m 3 and the melting point was 112°C.

[0089] [Ethylene-α-olefin copolymer (C-2)] An ethylene-butene copolymer, Tafmer A4085s (trade name) (manufactured by Mitsui Chemicals, Inc.), was used. The content of ethylene-derived monomer units in Tafmer A4085s was 80% by mass. The melt flow rate measured at 190°C was 3.6 g / 10 min, and the density was 885 kg / m 3 and no melting point was observed.

[0090] [Butene homopolymer (C-3)] The butene homopolymer, Tafmer BL4000 (product name) (manufactured by Mitsui Chemicals, Inc.), was used. The melt flow rate measured at 190°C was 1.8 g / 10 min, and the density was 915 kg / m 3 and the melting point was 112°C.

[0091] [Ethylene-propylene copolymer (C-4)] Vistamaxx 6102FL (trade name) (manufactured by ExxonMobil Japan Co.) was used, which is an ethylene-propylene copolymer. The content of ethylene-derived monomer units in Vistamaxx 6102FL was 16% by mass. The melt flow rate measured at 190 °C was 1.3 g / 10 min, and the density was 862 kg / m 3 and no melting point was observed.

[0092] [Ethylene homopolymer (D-1)] An ethylene homopolymer, G1801 (trade name) (manufactured by Keiyo Polyethylene Co., Ltd.), was used. The melt flow rate measured at 190°C was 7 g / 10 min, and the density was 961 kg / m 3 and the melting point was 130°C.

[0093] [Antiblocking agent masterbatch] As the antiblocking agent masterbatch, a 10 mass % masterbatch of Sylysia 550 (manufactured by Fuji Silysia Chemical Ltd.) described in Example 4 of JP-A No. 2003-170420 was used, which will hereinafter be referred to as AB.

[0094] [Example 1] A composition was obtained by pellet-blending 78% by mass of a propylene-based polymer material (1), 20% by mass of an ethylene-α-olefin copolymer (C-1), and 2% by mass of an antiblocking agent masterbatch. The blending ratio of the composition is shown in Table 1. The obtained composition was analyzed by temperature gradient interaction chromatography. The elution amount measured up to 160°C was 100% by mass, while the elution amount measured between 70 and 95°C was 24% by mass. The cold xylene soluble content was 12.1% by mass, and the melting point was 133.1°C. The resulting composition was melt-extruded at a resin temperature of 250°C using a 50mm T-die film-forming device (Tanabe Plastics Co., Ltd., Model V-50-F600 film-forming device with a 400mm wide T-die). The extrusion was then cooled and solidified while being wound up on a chill roll through which 40°C cooling water was passed, yielding a 30µm-thick film. The resulting film was used to measure the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0095] [Example 2] A composition was obtained by pellet-blending 74% by mass of a propylene-based polymer material (1), 19% by mass of an ethylene-α-olefin copolymer (C-1), 5% by mass of an ethylene homopolymer (C-3), and 2% by mass of an antiblocking agent masterbatch. The composition's blending ratios are shown in Table 1. Temperature gradient interaction chromatography of the obtained composition showed that the elution amount measured up to 160°C was 100% by mass, while the elution amount measured between 70 and 95°C was 23% by mass, the cold xylene soluble content was 11.6% by mass, and the melting point was 136.4°C. The resulting composition was used to produce a 30 μm thick film in the same manner as in Example 1. The resulting film was used to measure the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0096] [Example 3] A composition was obtained by pellet-blending 78% by mass of a propylene-based polymer material (1), 20% by mass of a butene homopolymer (C-3), and 2% by mass of an antiblocking agent masterbatch. The blending ratio of the composition is shown in Table 1. The obtained composition was measured by temperature gradient interaction chromatography. The elution amount measured up to 160°C was 100% by mass, while the elution amount measured between 70 and 95°C was 25% by mass. The cold xylene soluble content was 11.6% by mass, and the melting point was 115.6°C. The resulting composition was used to produce a 30 μm thick film in the same manner as in Example 1. The resulting film was used to measure the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0097] [Example 4] A composition was obtained by pellet-blending 78% by mass of a propylene-based polymer material (1), 20% by mass of an ethylene-α-olefin copolymer (C-2), and 2% by mass of an antiblocking agent masterbatch. The composition ratios are shown in Table 1. The obtained mixture was analyzed by temperature gradient interaction chromatography. The elution amount measured up to 160°C was 100% by mass, while the elution amount measured between 70 and 95°C was 27% by mass. The cold xylene soluble content was 13.8% by mass, and the melting point was 132.2°C. The resulting composition was used to produce a 30 μm thick film in the same manner as in Example 1. The resulting film was used to measure the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0098] [Comparative Example 1] A composition was obtained by pellet-blending 98% by mass of the propylene polymer material (1) and 2% by mass of the antiblocking agent masterbatch. The blending ratio of the composition is shown in Table 1. The obtained composition had an elution amount of 100% by mass measured up to 160°C, an elution amount of 30% by mass measured between 70 and 95°C, a cold xylene soluble content of 14.1% by mass, and a melting point of 134.1°C. The resulting composition was used to produce a 30 μm thick film in the same manner as in Example 1. The resulting film was used to measure the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0099] Comparative Example 2 A composition was obtained by pellet-blending 93% by mass of a propylene-based polymer material (1), 5% by mass of an ethylene homopolymer (D-1), and 2% by mass of an antiblocking agent masterbatch. The blending ratio of the composition is shown in Table 1. The obtained composition was measured by temperature gradient interaction chromatography. The elution amount measured up to 160°C was 100% by mass, while the elution amount measured between 70 and 95°C was 29% by mass. The cold xylene soluble content was 13.0% by mass, and the melting point was 128.3°C. The resulting composition was used to produce a 30 μm thick film in the same manner as in Example 1. The resulting film was used to measure the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0100] Comparative Example 3 A composition was obtained by pellet-blending 78% by mass of a propylene-based polymer material (2), 20% by mass of an ethylene-α-olefin copolymer (C-2), and 2% by mass of an antiblocking agent masterbatch. The blending ratio of the composition is shown in Table 1. The obtained composition was measured by temperature gradient interaction chromatography. The elution amount measured up to 160°C was 100% by mass, while the elution amount measured between 70 and 95°C was 48% by mass. The cold xylene soluble content was 7.6% by mass, and the melting point was 139.9°C. The resulting composition was used to produce a 30 μm thick film in the same manner as in Example 1. The resulting film was used to measure the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0101] Comparative Example 4 A composition was obtained by pellet-blending 78% by mass of a propylene-based polymer material (2), 20% by mass of an ethylene-α-olefin copolymer (C-1), and 2% by mass of an antiblocking agent masterbatch. The blending ratio of the composition is shown in Table 1. The obtained composition was measured by temperature gradient interaction chromatography. The elution amount measured up to 160°C was 100% by mass, while the elution amount measured between 70 and 95°C was 44% by mass. The cold xylene soluble content was 5.2% by mass, and the melting point was 140.3°C. The resulting composition was used to produce a 30 μm thick film in the same manner as in Example 1. The resulting film was used to measure the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0102] Comparative Example 5 A composition was obtained by pellet-blending 78% by mass of propylene-based polymer material (1), 20% by mass of ethylene-propylene copolymer (C-4), and 2% by mass of an antiblocking agent masterbatch. The blending ratio of the composition is shown in Table 1. The obtained composition was measured by temperature gradient interaction chromatography. The elution amount measured up to 160°C was 100% by mass, while the elution amount measured between 70 and 95°C was 25% by mass. The cold xylene soluble content was 30.9% by mass, and the melting point was 132.2°C. The resulting composition was used to produce a film having a thickness of 30 μm in the same manner as in Example 1. The resulting film was measured for the minimum sealable temperature, blocking strength, and Young's modulus. The measurement results are shown in Table 2.

[0103] [Table 1]

[0104] [Table 2]

[0105] As can be seen from the results in Table 2, the olefin polymer compositions of the examples which satisfy all of the constituent requirements of the present invention can form films which can be heat-sealed at relatively low temperatures, and the films have good blocking resistance.

Claims

1. Satisfy the following requirements (1) to (3), A propylene-based polymer material (I) containing at least one propylene-based polymer and having a melting point of more than 120°C; an olefin polymer material (II) containing at least one olefin polymer and having a melting point of 120°C or less; Contains The propylene-based polymer material (I) comprises a propylene-ethylene copolymer (A) containing a monomer unit derived from propylene and a monomer unit derived from ethylene; a propylene-α-olefin copolymer (B) containing a monomer unit derived from propylene and a monomer unit derived from an α-olefin having 4 to 12 carbon atoms; Contains the olefin polymer material (II) is at least one polymer (C) selected from the group consisting of ethylene-α-olefin copolymers containing monomer units derived from ethylene and monomer units derived from an α-olefin having 4 to 12 carbon atoms, and α-olefin polymers containing 50 mass% or more of monomer units derived from an α-olefin having 4 to 12 carbon atoms; An olefin polymer composition comprising: Requirement (1): In temperature gradient interaction chromatography of the olefin polymer composition measured using a gel permeation chromatograph equipped with a graphite-packed column, the elution amount measured at 70°C to 95°C is 10.0% by mass to 28.0% by mass relative to 100% by mass of the elution amount measured up to 160°C. Requirement (2): The amount of cold xylene solubles is 20.0 mass % or less. Requirement (3): The melting point is 150°C or less.

2. 2. The olefin polymer composition according to claim 1, wherein, in the requirement (1), the elution amount at 70°C to 75°C is 3.0% by mass to 7.0% by mass and the elution amount at 90°C to 95°C is 2.0% by mass to 18.0% by mass.

3. 3. The olefin polymer composition according to claim 1, wherein, in the requirement (3), the melting point is 110°C to 135°C.

4. The olefin polymer composition according to any one of claims 1 to 3, wherein the propylene-α-olefin copolymer (B) contains 3% by mass to 30% by mass of monomer units derived from 1-butene.

5. The olefin polymer composition according to any one of claims 1 to 4, wherein the polymer (C) is an ethylene-α-olefin copolymer containing a monomer unit derived from ethylene and a monomer unit derived from an α-olefin having 4 to 6 carbon atoms.

6. The olefin polymer composition according to any one of claims 1 to 4, wherein the polymer (C) is a homopolymer of an α-olefin having 4 to 6 carbon atoms.

7. Furthermore, it contains a monomer unit derived from ethylene and has a density of 940 kg / m ３ ~970 kg / m ３ The olefin polymer composition according to any one of claims 1 to 6, comprising an ethylene polymer (D) represented by the formula:

8. A film comprising the olefin polymer composition according to any one of claims 1 to 7.

9. The film according to claim 8, wherein the Young's modulus in the MD direction of the film is 400 MPa to 500 MPa.

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