Sealant film, laminate, and production method thereof

Abstract

To provide a sealant film and a laminate having high heat seal strength and high peeling energy.SOLUTION: A sealant film comprises a heat fusion layer and an adjacent layer laminated adjacent to the heat fusion layer. The sealant film satisfies the following requirements (1) and (2). The heat fusion layer contains a specific amount of a propylene-based polymer (AH) satisfying the following requirement (4) and a specific amount of an olefin-based polymer (BH) satisfying the following requirement (3). The adjacent layer contains a specific amount of a propylene-based polymer (AA) satisfying the following requirement (4) and a specific amount of an olefin-based polymer (BA) satisfying the following requirement (3). Requirement (1): at least one outermost layer in the sealant film is the heat fusion layer. Requirement (2): the sealant film is an unstretched film. Requirement (3): the melting point is less than 120°C or unobservable. Requirement (4): the melting point is 120°C or more and 170°C or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a sealant film, a laminate, and a method for producing the same.

Background Art

[0002] As films for heat-seal packaging, crystalline polypropylene films such as biaxially stretched films (OPP films) and unstretched films (CPP films) made of crystalline polypropylene are widely used. Crystalline polypropylene films are excellent in rigidity, heat resistance, etc., but since the heat-seal temperature during adhesion is high, the heat-sealability is usually improved by laminating a sealant layer. The heat-seal strength of a crystalline polypropylene film laminated with a sealant layer is usually 20 to 30 N / 15 mm, but there are problems such as peeling marks remaining due to the film tearing when peeling, and the peeling energy being small.

[0003] As a method for solving the problem of remaining peeling marks, there is a method of using a composition in which an ethylene-based copolymer is blended with a propylene-based copolymer or a film using only an ethylene-based copolymer. For example, Patent Document 1 describes a laminate having a sealant film containing a polypropylene resin, an ethylene·α-olefin random copolymer, and a 1-butene·α-olefin random copolymer, and excellent in low-temperature heat-sealability. On the other hand, Patent Document 2 describes a sealant film composed of a heat-fusion layer and an adjacent layer adjacent to the heat-fusion layer, and containing an olefin-based polymer and a propylene-based polymer having a melting point in a specific range, and a laminate having the sealant film, and it is described that the laminate is excellent in low-temperature heat-sealability and peeling energy.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] For a laminate using a composition of an ethylene-based polymer and polypropylene, after adhesion by heat sealing, the peeling form during peeling is cohesive peeling, which is a stable peeling form, but the heat seal strength is weak, and there is a possibility that the seal part peels off when a strong force is continuously applied. In addition, for the laminates described in Patent Document 1 and Patent Document 2, when heat sealing is performed under high-temperature conditions, there is room for improvement from the viewpoint of peeling energy. Heat sealing may be performed at a high temperature, for example, when manufacturing a package from a laminate in a short time. Therefore, an object of the present invention is to provide a sealant film and a laminate having high heat seal strength and high peeling energy. In particular, an object of the present invention is to provide a sealant film and a laminate having high heat seal strength and high peeling energy when heat sealed at a high temperature. Means for Solving the Problems

[0006] The present invention relates to, for example, the following [1] to

[11] .

[0007] [1] A sealant film including a heat-sealing layer and an adjacent layer laminated adjacent to the heat-sealing layer, wherein the sealant film satisfies the following requirements (1) and (2), the heat-sealing layer contains 30 to 90 parts by mass of a propylene-based polymer (AH) that satisfies the following requirement (4) and 10 to 70 parts by mass of an olefin-based polymer (BH) that satisfies the following requirement (3) (however, the total of the propylene-based polymer (AH) and the olefin-based polymer (BH) is 100 parts by mass).), The adjacent layer contains 45 to 85 parts by mass of a propylene-based polymer (AA) that satisfies the following requirement (4) and 15 to 55 parts by mass of an olefin-based polymer (BA) that satisfies the following requirement (3) (however, the total of the propylene-based polymer (AA) and the olefin-based polymer (BA) is 100 parts by mass). Sealing film. Requirement (1) At least one of the outermost layers in the sealing film is the heat-sealing layer. Requirement (2) The sealing film is an unstretched film. Requirement (3) The melting point is less than 120 °C or not observed. Requirement (4) The melting point is 120 °C or higher and 170 °C or lower.

[0008] [2] The olefin-based polymer (BH) contains at least one polymer selected from the group consisting of an ethylene polymer (BH1), a propylene polymer (BH2), and a 1-butene polymer (BH3). The sealing film according to [1], wherein the olefin-based polymer (BA) contains at least one polymer selected from the group consisting of an ethylene polymer (BA1), a propylene polymer (BA2), and a 1-butene polymer (BA3).

[0009] [3] The sealing film according to [2], wherein the olefin-based polymer (BA) is the ethylene polymer (BA1), and the ethylene polymer (BA1) is at least one polymer selected from the group consisting of high-pressure low-density polyethylene, linear low-density polyethylene, and an ethylene / α-olefin copolymer.

[0010] [4] The sealing film according to any one of [1] to [3], wherein the heat-sealing strength when the heat-sealing layers are heat-sealed at 140 °C is 15 N / 15 mm or more.

[0011] [5] A laminate comprising a sealant film according to any one of [1] to [4] and a base film, wherein the heat-sealing layer, the adjacent layer, and the base film are laminated in this order, and at least one outermost layer of the laminate is the heat-sealing layer. Laminate.

[0012] [6] The laminate according to [5], wherein the laminate includes at least one layer selected from the group consisting of a printing layer, a barrier layer, and an embossing layer.

[0013] [7] A package formed of the laminate according to [5] or [6].

[0014] [8] A method for manufacturing a sealant film according to any one of [1] to [4], the method including a step of laminating the heat-sealing layer and the adjacent layer adjacent to each other.

[0015] [9] A method for manufacturing a laminate according to [5] or [6], the method including a step of laminating the sealant film and the base film in the order of the heat-sealing layer / the adjacent layer / the base film.

[0016]

[10] wherein at least one layer selected from the group consisting of the printing layer, the barrier layer, and the embossing layer is the barrier layer, and the method for manufacturing a laminate according to [6] includes a step of laminating the sealant film and the base film in the order of the heat-sealing layer / the adjacent layer / the base film and forming the barrier layer as one layer of the laminate by a metal vapor deposition method, a coating method, or a coextrusion method.

[0017]

[11] A laminate including a heat-sealing layer and an adjacent layer laminated adjacent to the heat-sealing layer, and a base film, The heat-sealing layer, the adjacent layer, and the base film are laminated in this order. At least one of the outermost layers in the laminate is the heat-sealing layer. When heat-sealing the heat-sealing layers at 140 °C, the heat-sealing strength is 15 N / 15 mm or more, and the peel energy is 100 mJ or more. Laminate.

Advantages of the Invention

[0018] The sealant film and laminate of the present invention have high heat-sealing strength and high peel energy. In particular, the sealant film and laminate of the present invention have high heat-sealing strength and high peel energy when heat-sealing is performed under high-temperature conditions.

Embodiments for Carrying Out the Invention

[0019] In this specification, unless otherwise specified, the homopolymer and copolymer may be described as "polymer" without particular distinction.

[0020] [Sealant Film] The sealant film according to the present invention is a sealant film including a heat-sealing layer and an adjacent layer laminated adjacent to the heat-sealing layer, The sealant film satisfies the following requirements (1) and (2), The heat-sealing layer contains 30 to 90 parts by mass of a propylene-based polymer (AH) that satisfies the following requirement (4) and 10 to 70 parts by mass of an olefin-based polymer (BH) that satisfies the following requirement (3) (however, the total of the propylene-based polymer (AH) and the olefin-based polymer (BH) is 100 parts by mass).), The adjacent layer contains 45 to 85 parts by mass of a propylene-based polymer (AA) that satisfies the following requirement (4) and 15 to 55 parts by mass of an olefin-based polymer (BA) that satisfies the following requirement (3) (however, the total of the propylene-based polymer (AA) and the olefin-based polymer (BA) is 100 parts by mass).). Requirement (1) At least one of the outermost layers in the sealant film is the heat-sealing layer. Requirement (2) The sealant film is an unstretched film. Requirement (3) The melting point is less than 120°C or not observed. Requirement (4) The melting point is 120°C or higher and 170°C or lower.

[0021] In the present invention, the melting point of the polymer is the melting point measured by the following method. <Measurement method of melting point> Using a differential scanning calorimeter (DSC, for example, DSC7020 manufactured by SII), about 10 mg of the sample is heated from 30°C to 200°C at a heating rate of 10°C / min in a nitrogen atmosphere and held at that temperature for 10 minutes. Then, it is cooled to 30°C at a cooling rate of 10°C / min and held at that temperature for 5 minutes, and then heated to 200°C at a heating rate of 10°C / min. The endothermic peak observed during this second heating is taken as the melting peak, and the temperature at which the melting peak appears is taken as the melting point (Tm). When there are multiple melting peaks, the melting peak with the highest temperature is adopted. Also, "the melting point is not observed" means that no melting peak with a heat of fusion of 1 J / g or more is observed.

[0022] The measurement methods of the heat seal strength and the peel energy, and the determination method of the peel form will be described in detail in the Examples section. Usually, the peel energy is obtained as the area of the peel curve (S-S curve) at the time of peeling. That is, when the heat seal strength is high and the tensile distance (strain amount) from the start of peeling to the occurrence of breakage is long, the peel energy tends to be high.

[0023] When the heat-sealing layers are heat-sealed at 140°C under the conditions described in the Examples section below, the heat seal strength is preferably 10 N / 15 mm or more, more preferably 15 N / 15 mm or more. When heat-sealing the heat-sealing layers together and then peeling them off, the peeling mode is preferably cohesive peeling. When the peeling mode is cohesive peeling, the tensile distance (strain amount) from the start of peeling to the occurrence of breakage tends to be long, and the peeling energy of the sealant film tends to be high.

[0024] When the heat-sealing layers are heat-sealed at 140 °C under the conditions described in the Examples section below, the peeling energy is preferably 50 mJ or more, more preferably 70 mJ or more, still more preferably 80 mJ or more, even more preferably 90 mJ or more, and particularly preferably 100 mJ or more. When the heat-sealing strength of the sealant film is high and / or the peeling mode is cohesive peeling, the peeling energy tends to be high. When the heat-sealing strength and the peeling energy are within the above ranges, the burst resistance of the package produced from the laminate is improved.

[0025] When the heat-sealing layers are heat-sealed with contaminants at 160 °C under the conditions described in the Examples section below, the contaminant heat-sealing strength is preferably 5 N / 15 mm or more, more preferably 7 N / 15 mm or more, and still more preferably 10 N / 15 mm or more. When the contaminant heat-sealing strength is within the above range, the contaminant peeling energy tends to be high.

[0026] When the heat-sealing layers are heat-sealed with contaminants at 160 °C under the conditions described in the Examples section below, the contaminant peeling energy is preferably 30 mJ or more, more preferably 50 mJ or more, and still more preferably 100 mJ or more. A sealant film or laminate in which the contaminant heat-sealing strength in the sealant film is high and the peeling mode is cohesive peeling tends to have a high contaminant peeling energy.

[0027] At least one of the outermost layers in the sealant film is the heat-sealing layer. The laminate containing the sealant film is used, for example, in a package produced by heat-sealing or contaminant heat-sealing the heat-sealing layers together. As a method for heat-sealing the heat-sealing layers to each other, for example, there is a method in which two sealant films or laminates are prepared, the heat-sealing layer surfaces are opposed to each other, or the sealant film or laminate is bent and arranged so that the heat-sealing layers face each other, and then heat-sealed.

[0028] The thickness of the sealant film is usually 5 to 100 μm, preferably 7.5 to 75 μm, more preferably 10 to 50 μm, and particularly preferably 10 to 30 μm. When there are a plurality of sealant films, it is preferable that each sealant film has the above thickness.

[0029] The thickness of the heat-sealing layer is usually 2.5 to 50 μm. The lower limit value of the above range is preferably 3 μm, more preferably 4 μm, and particularly preferably 5 μm. Also, the upper limit value of the above range is preferably 30 μm, more preferably 20 μm, and particularly preferably 15 μm.

[0030] The thickness of the adjacent layer is usually 2.5 to 50 μm. The lower limit value of the above range is preferably 3 μm, more preferably 4 μm, and particularly preferably 5 μm. Also, the upper limit value of the above range is preferably 30 μm, more preferably 20 μm, and particularly preferably 15 μm.

[0031] The total thickness of the sealant film is usually 50% or less, preferably 40% or less, based on the total thickness of the laminate including the base material layer described later. The sealant film is an unstretched film. Since the sealant film is an unstretched film, the heat shrinkage of the sealant film tends to be suppressed even when the heat-sealing layers are heat-sealed at a high temperature.

[0032] The sealant film may, within a range not impairing the object of the present invention, contain, as necessary, resins other than the polymers (AH), (BH), (AA), and (BA) described later, tackifiers, weather stabilizers, heat stabilizers, antistatic agents, slip agents, antiblocking agents, lubricants, pigments, dyes, plasticizers, antioxidants, hydrochloric acid absorbers, and antioxidants and other additives.

[0033] 《Heat-sealing layer》 The sealant film includes a heat-sealing layer. The heat-sealing layer contains a propylene-based polymer (AH) and an olefin-based polymer (BH).

[0034] 〈Propylene-based polymer (AH)〉 The propylene-based polymer (AH) is not particularly limited as long as its melting point is 120°C or higher and 170°C or lower. By including the propylene-based polymer (AH) in the heat-sealing layer, the sealant film has excellent heat-seal strength. Examples of the propylene-based polymer (AH) include a homopolymer of propylene [also referred to as homopolymer PP: hPP], a random copolymer of propylene and ethylene and / or an α-olefin having 4 to 20 carbon atoms [also referred to as random PP: rPP], and a block copolymer [also referred to as block PP: bPP].

[0035] Examples of the α-olefin having 4 to 20 carbon atoms include 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-nonadecene, and 1-eicosene. Among them, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene are preferred, and 1-butene is more preferred. The α-olefin having 4 to 20 carbon atoms may be one kind or two or more kinds.

[0036] The propylene-based polymer (AH) is preferably a random copolymer obtained by copolymerizing propylene with ethylene and / or an α-olefin having 4 or more carbon atoms. From the viewpoint of the balance between the blocking property and the heat-sealing property of the sealant film, the propylene-based polymer (AH) is preferably a copolymer of propylene, ethylene, and an α-olefin having 4 or more carbon atoms, and particularly preferably a propylene-ethylene-1-butene copolymer. When the propylene-based polymer (AH) is a copolymer, it usually contains 85 to 99 mol%, preferably 90 to 99 mol%, of the structural units derived from propylene based on all the structural units.

[0037] As the propylene, ethylene, and / or α-olefin having 4 to 20 carbon atoms, which are the raw materials of the propylene-based polymer (AH), for example, monomers derived from fossil fuels may be used, monomers derived from biomass may be used, or monomers derived from fossil fuels and monomers derived from biomass may be used. These monomers may be used alone or in combination of two or more.

[0038] The melting point of the propylene-based polymer (AH) is preferably 120°C or higher and 155°C or lower, more preferably 130°C or higher and 150°C or lower.

[0039] The MFR of the propylene-based polymer (AH) measured under the conditions of 230°C and a load of 2.16 kg in accordance with ASTM D1238 is preferably in the range of 0.1 to 100 g / 10 min, more preferably 0.5 to 50 g / 10 min, and even more preferably 1 to 20 g / 10 min.

[0040] The propylene-based polymer (AH) can be produced by polymerizing a monomer in the presence of a known catalyst such as a Ziegler-Natta catalyst and a metallocene catalyst by a known polymerization method such as a gas phase method, a bulk method, and a slurry method. As a method for setting the melting point of the propylene-based polymer (AH) to 120°C or higher and 170°C or lower, for example, when polymerizing with a Ziegler-Natta catalyst, the comonomer content is controlled to less than 20 mol%, and when polymerizing with a metallocene catalyst, the comonomer content is controlled to less than 10 mol%. Examples of such methods include controlling polymerization conditions such as the monomer feed amount.

[0041] The propylene-based polymer (AH) contained in the heat-sealing layer may be the same as or different from the propylene-based polymer (AA) contained in the adjacent layer. The propylene-based polymer (AH) may be a single polymer or two or more polymers.

[0042] 〈Olefin-based polymer (BH)〉 The olefin-based polymer (BH) is not particularly limited as long as it is an olefin-based polymer having a melting point of less than 120°C or not observable. When the heat-sealing layer contains the olefin-based polymer (BH), the sealant film has excellent heat-sealability.

[0043] Examples of the olefin-based polymer (BH) include homopolymers of α-olefins, copolymers of two or more α-olefins, and copolymers of α-olefins and monomers other than α-olefins.

[0044] Examples of the olefin-based polymer (BH) include Ethylene-based polymers containing more than 50 mol% and up to 100 mol% of structural units derived from ethylene, such as homopolymers of ethylene and ethylene-α-olefin copolymers (ethylene-α-olefin copolymers) of ethylene and α-olefins having 3 or more carbon atoms [hereinafter, in the present invention, may sometimes be referred to as "ethylene polymer (BH1)"]. A propylene-based polymer containing more than 50 mol% and 100 mol% or less of a structural unit derived from propylene such as a copolymer of propylene with ethylene and / or an α-olefin having 4 or more carbon atoms (propylene-α-olefin copolymer) [hereinafter, in the present invention, may be referred to as "propylene polymer (BH2)"], and A 1-butene-based polymer containing more than 50 mol% and 100 mol% or less of a structural unit derived from 1-butene such as a homopolymer of 1-butene and a copolymer of 1-butene with ethylene, propylene and / or an α-olefin having 5 or more carbon atoms (1-butene-α-olefin copolymer) [hereinafter, in the present invention, may be referred to as "1-butene polymer (BH3)"], and the like.

[0045] 〈Ethylene polymer (BH1)〉 When the ethylene polymer (BH1) is a copolymer, examples of the α-olefin having 3 or more carbon atoms copolymerized with ethylene include α-olefins having 3 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and 1-tetradecene. A sealant film containing an ethylene polymer (BH1) in which the α-olefin is 1-butene, 1-hexene or 1-octene is excellent in the balance of strength, flexibility and heat sealability.

[0046] The α-olefin copolymerized with ethylene is not limited to one kind and may be two or more kinds. When the ethylene polymer (BH1) is a copolymer, it usually contains more than 50 mol% and 99 mol% or less, preferably 70 to 95 mol%, of the structural unit derived from ethylene with respect to all the structural units.

[0047] 〈Propylene polymer (BH2)〉 When the propylene polymer (BH2) is a copolymer, examples of the α-olefin having 4 or more carbon atoms copolymerized with propylene include the above α-olefins other than propylene. The α-olefin copolymerized with propylene may be one kind or two or more kinds (including ethylene). As the propylene polymer (BH2), a propylene / ethylene copolymer and a propylene / 1-butene copolymer are preferable, and a propylene / 1-butene copolymer is more preferable. The propylene / ethylene copolymer and the propylene / 1-butene copolymer are excellent in flexibility and can promote stress relaxation of the sealant film. The propylene / 1-butene copolymer has high crystallinity even with a low melting point and is less likely to deteriorate the film blocking property. When the propylene polymer (BH2) is a copolymer, it usually contains 55 to 99 mol%, preferably 60 to 90 mol%, of the structural units derived from propylene based on all the structural units.

[0048] 〈1-Butene polymer (BH3)〉 When the 1-butene polymer (BH3) is a copolymer, examples of the α-olefin having 5 or more carbon atoms copolymerized with 1-butene include the above-mentioned α-olefins other than propylene and 1-butene. The α-olefin copolymerized with 1-butene may be one kind or two or more kinds (including ethylene and propylene).

[0049] As the 1-butene polymer (BH3), a 1-butene / ethylene copolymer and a 1-butene / propylene copolymer are preferable. Since the 1-butene / ethylene copolymer and the 1-butene / propylene copolymer have a low melting point, a sealant film containing these copolymers is excellent in heat sealability and is less likely to deteriorate the film blocking property. When the 1-butene polymer (BH3) is a copolymer, it usually contains 55 to 99 mol%, preferably 60 to 98 mol%, of the structural units derived from 1-butene based on all the structural units.

[0050] The olefin polymer (BH) preferably contains at least one polymer selected from the group consisting of an ethylene polymer (BH1), a propylene polymer (BH2), and a 1-butene polymer (BH3). The olefin polymer (BH) contained in the heat-sealing layer preferably contains a propylene polymer (BH2) and / or a 1-butene polymer (BH3), more preferably is a propylene polymer (BH2) and / or a 1-butene polymer (BH3), and even more preferably is a propylene-1-butene copolymer and / or a 1-butene-propylene copolymer. Even if the melting points of the propylene polymer (BH2) and the 1-butene polymer (BH3) are low, it is difficult to deteriorate the film blocking property of the sealant film. The sealant film containing the propylene polymer (BH2) and / or the 1-butene polymer (BH3) tends to have excellent heat-sealing properties.

[0051] As the monomer that is the raw material of the olefin polymer (BH), for example, a monomer derived from fossil fuel may be used, a monomer derived from biomass may be used, or a monomer derived from fossil fuel and a monomer derived from biomass may be used. These monomers may be used alone or in combination of two or more.

[0052] The melting point of the olefin polymer (BH) is preferably less than 120°C, more preferably less than 110°C. The MFR of the olefin polymer (BH) measured under the conditions of 230°C and a load of 2.16 kg in accordance with ASTM D1238 is preferably in the range of 0.1 to 100 g / 10 min, more preferably in the range of 1 to 20 g / 10 min.

[0053] The MFR of the olefin polymer (BH) measured under the conditions of 190°C and a load of 2.16 kg in accordance with ASTM D1238 is preferably in the range of 0.1 to 100 g / 10 min, more preferably in the range of 0.5 to 50 g / 10 min, and even more preferably in the range of 1 to 20 g / 10 min.

[0054] The olefin polymer (BH) contained in the heat-sealing layer may be the same as or different from the olefin polymer (BA) contained in the adjacent layer. The olefin polymer (BH) contained in the heat-sealing layer may be one type or two or more types.

[0055] The heat-sealing layer contains 30 to 90 parts by mass of a propylene-based polymer (AH) and 10 to 70 parts by mass of an olefin-based polymer (BH), preferably 35 to 85 parts by mass of a propylene-based polymer (AH) and 15 to 65 parts by mass of an olefin-based polymer (BH), more preferably 40 to 80 parts by mass of a propylene-based polymer (AH) and 20 to 60 parts by mass of an olefin-based polymer (BH) (however, the total of the propylene-based polymer (AH) and the olefin-based polymer (BH) is 100 parts by mass). When the contents of the propylene-based polymer (AH) and the olefin-based polymer (BH) in the heat-sealing layer are within the above ranges, the sealant film has high heat-sealing strength and a tendency of high peel energy even when heat-sealed at a high temperature.

[0056] 《Adjacent layer》 The sealant film includes an adjacent layer laminated adjacent to the heat-sealing layer. That is, the adjacent layer is laminated adjacent to the heat-sealing layer which is at least one outermost layer of the sealant film. The adjacent layer is a layer that controls the peeling form when peeling the sealant film after heat-sealing the heat-sealing layers together.

[0057] The adjacent layer contains a propylene-based polymer (AA) that satisfies the above requirement (4) and an olefin-based polymer (BA) that satisfies the above requirement (3).

[0058] 〈Propylene-based polymer (AA)〉 The propylene-based polymer (AA) is not particularly limited as long as its melting point is 120°C or higher and 170°C or lower. Examples of the propylene-based polymer (AA) include the same polymers as the propylene-based polymer (AH). As the propylene-based polymer (AA), a random copolymer obtained by copolymerizing propylene with ethylene and / or an α-olefin having 4 or more carbon atoms is preferred. From the viewpoint of the balance between the blocking property and the heat sealability of the sealant film, the propylene-based polymer (AA) is preferably a copolymer of propylene, ethylene, and an α-olefin having 4 or more carbon atoms, and particularly preferably a propylene-ethylene-1-butene copolymer. When the propylene-based polymer (AA) is a copolymer, it usually contains 85 to 99 mol%, preferably 90 to 99 mol%, of the structural units derived from propylene based on all the structural units.

[0059] As the propylene, ethylene, and / or α-olefin having 4 to 20 carbon atoms, which are the raw materials of the propylene-based polymer (AA), for example, monomers derived from fossil fuels, monomers derived from biomass, or a combination of monomers derived from fossil fuels and monomers derived from biomass may be used. These monomers may be used alone or in combination of two or more.

[0060] The melting point of the propylene-based polymer (AA) is preferably 120°C or higher and 155°C or lower, more preferably 130°C or higher and 150°C or lower. The MFR of the propylene-based polymer (AA) measured under the conditions of 230°C and a load of 2.16 kg in accordance with ASTM D1238 is preferably in the range of 0.1 to 100 g / 10 min, more preferably 0.5 to 50 g / 10 min, and even more preferably 1 to 20 g / 10 min.

[0061] The propylene-based polymer (AA) can be produced by polymerizing a monomer in the presence of a known catalyst such as a Ziegler-Natta catalyst and a metallocene catalyst by a known polymerization method such as a gas phase method, a bulk method, and a slurry method. As a method for setting the melting point of the propylene-based polymer (AA) to 120°C or higher and 170°C or lower, for example, when polymerizing with a Ziegler-Natta catalyst, the comonomer content is controlled to less than 20 mol%, and when polymerizing with a metallocene catalyst, the comonomer content is controlled to less than 10 mol%. Examples of such methods include controlling polymerization conditions such as the monomer feed amount. The propylene-based polymer (AA) may be a single polymer or two or more polymers.

[0062] 〈Olefin-based polymer (BA)〉 The olefin-based polymer (BA) is not particularly limited as long as it is an olefin-based polymer having a melting point of less than 120°C or not observed. When the olefin-based polymer (BA) having a melting point within the above range is included, the peeling form of the sealant film when the heat-fused layers are heat-sealed and then peeled tends to be cohesive peeling.

[0063] Examples of the olefin-based polymer (BA) include homopolymers of α-olefins, copolymers of two or more α-olefins, and copolymers of α-olefins and monomers other than α-olefins.

[0064] The olefin-based polymer (BA) preferably contains at least one polymer selected from the group consisting of an ethylene polymer (BA1), a propylene polymer (BA2), and a 1-butene polymer (BA3). Examples of the ethylene polymer (BA1) include polymers similar to the ethylene polymer (BH1). Examples of the propylene polymer (BA2) include polymers similar to the propylene polymer (BH2). Examples of the 1-butene polymer (BA3) include polymers similar to the 1-butene polymer (BH3).

[0065] The olefin polymer (BA) preferably contains an ethylene polymer (BA1), and more preferably is an ethylene polymer (BA1). The ethylene polymer (BA1) is preferably at least one polymer selected from the group consisting of high-pressure low-density polyethylene, linear low-density polyethylene, and ethylene / α-olefin copolymer, more preferably an ethylene / α-olefin copolymer, and even more preferably an ethylene / 1-butene copolymer. When the olefin polymer (BA) contains an ethylene polymer (BA1), the peeling form of the sealant film tends to be cohesive peeling due to the dispersion of the ethylene polymer (BA1) in the propylene polymer (AA). When the ethylene polymer (BA1) contains a structural unit derived from an α-olefin, the compatibility between the ethylene polymer (BA1) and the propylene polymer (AA) is excellent.

[0066] As the monomer that is a raw material of the olefin polymer (BA), for example, a monomer derived from fossil fuel, a monomer derived from biomass, or a combination of a monomer derived from fossil fuel and a monomer derived from biomass may be used. These monomers may be used alone or in combination of two or more.

[0067] The melting point of the olefin polymer (BA) is preferably less than 120°C, more preferably less than 110°C. The MFR of the olefin polymer (BA) measured under the conditions of 230°C and 2.16 kg load in accordance with ASTM D1238 is preferably in the range of 0.1 to 100 g / 10 min, more preferably in the range of 1 to 20 g / 10 min.

[0068] The MFR of the olefin polymer (BA) measured under the conditions of 190°C and 2.16 kg load in accordance with ASTM D1238 is preferably in the range of 0.1 to 100 g / 10 min, more preferably in the range of 0.5 to 50 g / 10 min, and even more preferably in the range of 1 to 20 g / 10 min. The density of the olefin polymer (BA) is preferably 850 to 900 kg / m 3 and more preferably 860 to 895 kg / m3 、 More preferably, it is 870 to 890 kg / m 3 . The olefin polymer (BA) may be one type or two or more types.

[0069] The adjacent layer contains 45 to 85 parts by mass of the propylene polymer (AA) and 15 to 55 parts by mass of the olefin polymer (BA). Preferably, it contains 45 to 70 parts by mass of the propylene polymer (AA) and 30 to 55 parts by mass of the olefin polymer (BA). More preferably, it contains 45 to 65 parts by mass of the propylene polymer (AA) and 35 to 55 parts by mass of the olefin polymer (BA). Particularly preferably, it contains 50 to 65 parts by mass of the propylene polymer (AA) and 35 to 50 parts by mass of the olefin polymer (BA) (however, the total of the propylene polymer (AA) and the olefin polymer (BA) is 100 parts by mass). When the contents of the propylene polymer (AA) and the olefin polymer (BA) in the adjacent layer are within the above ranges, even when the heat-sealing layers are heat-sealed at a high temperature, the peeling form of the sealant film is cohesive peeling, and the peeling energy tends to be high.

[0070] The sealant film can be produced, for example, by laminating the heat-sealing layer and the adjacent layer adjacent to each other. The heat-sealing layer and the adjacent layer may be laminated by a coextrusion method, or may be laminated by a general lamination method such as extrusion lamination, melt extrusion lamination, and dry lamination.

[0071] [Laminate] The first laminate of the present invention is a laminate including the sealant film according to the present invention and a base film, wherein the heat-sealing layer, the adjacent layer, and the base film are laminated in this order, and at least one outermost layer in the laminate is the heat-sealing layer. The second laminate of the present invention is a laminate including a sealant film containing a heat-sealing layer and an adjacent layer laminated adjacent to the heat-sealing layer, and a base film, wherein the heat-sealing layer, the adjacent layer, and the base film are laminated in this order, at least one outermost layer in the laminate is the heat-sealing layer, and when the heat-sealing layers are heat-sealed at 140°C, the heat-sealing strength is 15 N / 15 mm or more and the peel energy is 100 mJ or more.

[0072] Hereinafter, unless there are special circumstances, the first laminate and the second laminate will be described without particularly distinguishing them. Also, the first laminate and the second laminate may be described as "laminate" without particularly distinguishing them. The sealant film is a film that imparts heat-sealability to the laminate, and the base film is a film that supports the sealant film.

[0073] <Base film> The base film is usually at least one selected from a uniaxially stretched polypropylene film and an unstretched polypropylene film, preferably an unstretched polypropylene film. The base film usually has a thickness in the range of 10 to 200 μm, preferably 15 to 150 μm, more preferably 20 to 100 μm.

[0074] Examples of the polypropylene forming the base film include a homopolymer of propylene and a copolymer mainly containing a structural unit derived from propylene. The copolymer may be a random copolymer or a block copolymer. Examples of the monomer copolymerized with propylene include α-olefins other than propylene and diene compounds. The propylene content (content of structural units derived from propylene) in the polypropylene is usually 85 to 100 mol%, preferably 90 to 99.5 mol% in 100 mol% of all structural units derived from the comonomer, and the content of structural units derived from monomers other than propylene is usually 0 to 15 mol%, preferably 0.5 to 10 mol%.

[0075] Examples of α-olefins other than propylene include α-olefins having 2 or 4 to 20 carbon atoms such as ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and 1-tetradecene. The α-olefin may be used alone or in combination of two or more.

[0076] The MFR of the polypropylene measured under the conditions of 230 °C and 2.16 kg load in accordance with ASTM D1238 is preferably 0.1 to 10 g / 10 min, more preferably 0.5 to 8.0 g / 10 min, and the melting point (Tm) is preferably 120 to 165 °C, more preferably 135 to 150 °C.

[0077] Examples of the polypropylene include a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-1-butene random copolymer, a propylene-1-butene-ethylene random copolymer, a propylene-1-hexene random copolymer, a propylene-3-methyl-1-butene random copolymer, and a propylene-4-methyl-1-pentene random copolymer.

[0078] The polypropylene may be used alone or in combination of two or more. As the raw material of the polypropylene, for example, a monomer derived from fossil fuel, a monomer derived from biomass, or a combination of a monomer derived from fossil fuel and a monomer derived from biomass may be used. These monomers may be used alone or in combination of two or more.

[0079] The polypropylene can be produced, for example, by polymerizing a monomer by a known polymerization method such as a gas phase method, a bulk method, and a slurry method in the presence of a known catalyst such as a Ziegler-Natta catalyst and a metallocene catalyst.

[0080] The polypropylene may be the same polymer as the propylene-based polymer (AH), propylene-based polymer (AA), propylene polymer (BH2), or propylene polymer (BA2), or it may be a different polymer.

[0081] The base film is usually at least one selected from an unstretched polypropylene film (CPP film) that has not been subjected to a stretching treatment on a film formed from the polypropylene and a uniaxially stretched polypropylene film (MDOPP film) obtained by subjecting it to a uniaxial stretching treatment. Examples of the stretching method include known methods for manufacturing stretched films. Examples of the stretching method include roll stretching, tenter stretching, tubular stretching, and combinations of the above stretching methods. Since the sealant film is an unstretched film, when the base film is an unstretched polypropylene film (CPP film), the thermal shrinkage of the laminate tends to be suppressed even when the heat-sealing layers are heat-sealed at a high temperature.

[0082] The base film may be a single layer or may include a plurality of layers. The base film may contain additives such as resins other than polypropylene, tackifiers, weather stabilizers, heat stabilizers, antistatic agents, slip agents, antiblocking agents, lubricants, pigments, dyes, plasticizers, antioxidants, hydrochloric acid absorbers, and antioxidants.

[0083] Examples of the form of the laminate include a two-layer structure of a sealant film / base film and a three-layer structure of a sealant film / base film / sealant film. In the laminate, an adhesive layer can also be provided between the sealant film and the base film, such as a sealant film / adhesive layer / base film. When the laminate includes a plurality of layers made of a sealant film as in the three-layer structure, the plurality of sealant films may be the same as or different from each other.

[0084] The laminate may include only the sealant film and the base film, or may include, as a functional material layer, for example, films other than the sealant film and the base film. Examples of the functional material layer include a printing layer, a barrier layer, and an embossing layer. Examples of the barrier layer include a resin film vapor-deposited with an inorganic compound or inorganic oxide, and a metal foil. Examples of the embossing layer include a coating film of a resin having a special function. Examples of the printing layer include a resin film printed with a pattern. Examples of the resin film used for the functional material layer include resin films similar to the polypropylene film mentioned as the base film. Also, plastic compounding agents and additives similar to the additives that the base film may contain can be added to the functional material layer in any amount according to the purpose, as long as they do not adversely affect other properties.

[0085] The resin film is made using, for example, one or more resins selected from the same group of resins as the resin for the base film, and is manufactured by a conventionally used film-forming method such as an extrusion method, a casting method, a T-die method, a cutting method, and an inflation method, or by a multi-layer co-extrusion film-forming method using two or more resins. Furthermore, from the viewpoints of the strength, dimensional stability, and heat resistance of the film, for example, the resin film can be uniaxially stretched using a tenter method or a tubular method.

[0086] The laminate preferably includes at least one layer selected from the group consisting of a printing layer, a barrier layer, and an embossing layer, and more preferably includes a barrier layer.

[0087] The laminate can be manufactured, for example, by laminating the sealant film and the base film in the order of the heat-fusion layer / the adjacent layer / the base film.

[0088] The sealant film and the base film may be laminated by a coextrusion method, or may be laminated by common lamination methods such as extrusion lamination and dry lamination. After coextruding the sealant film and the base film, the base film may be further laminated.

[0089] The laminate may be manufactured by laminating the sealant film and the base film via an adhesive layer by dry lamination, non-solvent lamination, sand lamination, etc., or may be manufactured by laminating the sealant film and the base film by melt extrusion lamination. A method of manufacturing the laminate by dry lamination or melt extrusion lamination is preferred.

[0090] When the laminate includes a barrier layer, examples of its manufacturing method include a manufacturing method including a step of laminating the sealant film and the base film in the order of the heat-sealing layer / the adjacent layer / the base film, and forming the barrier layer as one layer of the laminate by a metal vapor deposition method, a coating method, or a coextrusion method.

[0091] The laminate manufactured by the above method can be stretched. As the stretching method, a known method for manufacturing a stretched film can be used. Examples of the stretching method include roll stretching, tenter stretching, tubular stretching, and combinations of the above stretching methods.

[0092] The laminate has high heat-sealing strength and high peel energy. A package can be obtained from the laminate. The package formed from the laminate is excellent in heat-sealing property and is difficult to break.

[0093] The package can be manufactured by combining a step of forming a bag-like container and a step of filling the contents. The bag-shaped container can be manufactured, for example, by facing the heat-sealing layers in the sealant film in the laminate to each other, or by facing the heat-sealing layer of the sealant film in the laminate and a film other than the sealant film, and then heat-sealing at least a part of the periphery thereof so as to have the shape of a desired container from the outer surface side. Also, a sealed bag-shaped container can be manufactured by heat-sealing the entire periphery. The package can be manufactured by heat-sealing the bottom and side portions of the bag-shaped container, filling the contents, and then heat-sealing the top. The package can be used in an automatic packaging apparatus for solid materials such as snack foods and bread, powders, or liquid materials.

[0094] A container obtained by previously forming the laminate into a cup shape by vacuum forming or pressure air forming, etc., a container obtained by injection molding, etc., or a container formed from a paper base material is filled with contents, the laminate is used as a lid material to cover the container, and the upper or side portion of the container is heat-sealed to obtain a container in which the contents are packaged. This container is suitably used for packaging instant noodles, miso, jelly, pudding, and snack foods, etc.

[0095] Recycled products of the laminate or the package can also be effectively utilized. Since the molded body that is a recycled product of the laminate or the package can reduce the amount of newly polymerized plastic used, it can contribute to reducing the environmental load.

Examples

[0096] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Each physical property shown in this example was measured by the following method.

[0097] [Heat-sealing strength and peeling form] Two laminates were arranged such that the heat-sealing layers of the sealant films faced each other, and heat-sealed at a heat-sealing temperature of 100 °C, 120 °C, 140 °C, 160 °C or 180 °C, a pressure of 0.2 MPa, a pressure application time of 1.0 second, and a seal bar width of 5 mm, and then allowed to cool. Next, test pieces with a width of 15 mm were cut from each of the specimens obtained by heat-sealing, and for each test piece, the peel strength when peeling the heat-sealed portion at a crosshead speed of 300 mm / min was measured, and the maximum value of the peel strength was taken as the heat-sealing strength.

[0098] Furthermore, the peel morphology after peeling the heat-sealed portion was confirmed, and the occurrence of cohesive peeling, film breakage, and film tearing was confirmed. Those that peeled only at the interface (cohesive peeling) were designated as "Peel", those in which the edge of the fused surface was broken (film breakage or film tearing) were designated as "Tear", and those in which "Peel" and "Tear" were mixed were designated as "Mixed".

[0099] [Peel Energy] Based on Kazuo Hishinuma, "Proposal of a method for measuring and evaluating the peel energy on the welded surface of thermal welding (heat sealing)", Journal of the Welding Society of Japan, 2006, Vol. 42, No. 4, P. 146-152., the peel energy S was calculated by the following formula.

[0100] [Equation] S: Peel energy (mJ) F: Tensile strength at each peel distance point (N) Δl: Unit distance for energy calculation (mm) Lt: Tensile distance at the time of fracture occurrence (mm)

[0101] [Foreign Matter Heat-Sealing Strength] Test specimens for measuring the foreign matter (powder) heat-sealing strength were prepared according to the following procedure. (1) Two samples were prepared by cutting the laminate produced in the examples and the like into a size of 120 mm in length and 120 mm in width. The two samples were overlapped so that their heat-sealing layers were on the inside, and one side at the longitudinal end and two sides at both transverse ends were heat-sealed over a width of 5 mm under the conditions of 200 °C, 0.2 MPa, and 1.0 second to produce a pouch with one side at the longitudinal end open. (2) 30 mg of creaming powder (trade name "Bright", manufactured by Nestle) was introduced through the opening of the pouch. Thereafter, the opening was heat-sealed over a width of 5 mm under the conditions of 200 °C, 0.2 MPa, and 1.0 second to seal the pouch. (3) The pouch was shaken to uniformly disperse the creaming powder inside the pouch, and it was used as the test piece. The heat-seal strength of the inclusion (powder) was evaluated by the same measurement method as the heat-seal strength. The minimum set temperature was 100 °C or 120 °C, and the subsequent set temperatures were 140 °C, 160 °C, and 180 °C, and the same measurement as the heat-seal strength was performed. For the test piece made of the laminate produced in the comparative example, only the measurement with the set temperature of 160 °C was performed.

[0102] [Inclusion peeling energy] The inclusion peeling energy S was calculated from the measurement results of the inclusion heat-seal strength by the same method as in the section of [Peeling energy].

[0103] The following polymers were used in the examples and comparative examples. [Heat-sealing layer] [Propylene-based polymer (AH)] As the propylene-based polymer (AH), the following rPP (AH-1) was used. · rPP (AH-1): Random propylene polymer having the following physical properties (Prime Polypro (registered trademark) F-724NPC manufactured by Prime Polymer Co., Ltd.) MFR (230 °C, 2.16 kg load, conforming to ASTM D1238): 7.0 g / 10 min, melting point: 146 °C

[0104] [Olefin-based polymer (BH)] As the olefin polymer (BH), the following BPR (BH3-1) and the following PBR (BH2-1) were used. ·BPR (BH3-1): 1-butene·propylene copolymer having the following physical properties MFR (230 °C, 2.16 kg load, conforming to ASTM D1238): 9.0 g / 10 min, MFR (190 °C, 2.16 kg load, conforming to ASTM D1238): 4.0 g / 10 min, melting point: 100 °C ·PBR (BH2-1): Propylene·1-butene copolymer having the following physical properties MFR (230 °C, 2.16 kg load, conforming to ASTM D1238): 7.0 g / 10 min, MFR (190 °C, 2.16 kg load, conforming to ASTM D1238): 3.0 g / 10 min, melting point: 75 °C

[0105] <Adjacent layer> 〈Propylene polymer (AA)〉 As the propylene polymer (AA), the following rPP (AA-1) was used. ·rPP (AA-1): The same random propylene polymer as the above rPP (AH-1)

[0106] 〈Olefin polymer (BA)〉 As the olefin polymer (BA), the following EBR (BA1-1) was used. ·EBR (BA1-1): Ethylene·1-butene copolymer having the following physical properties MFR (190 °C, 2.16 kg load, conforming to ASTM D1238): 1.2 g / 10 min, density (conforming to ASTM D1505): 885 kg / m 3 , melting point: 66 °C, ethylene content: 89 mol%

[0107] <Base film> As the polypropylene for forming the base film, the same random propylene polymer as the above rPP (AH-1) was used.

[0108] [Example 1] 70 parts by mass of rPP(AH-1) and 30 parts by mass of BPR(BH3-1) were blended to prepare a composition for producing a heat-sealing layer, and 55 parts by mass of rPP(AA-1) and 45 parts by mass of EBR(BA1-1) were blended to prepare a composition for producing an adjacent layer. Using three extruders connected with a T-die, the composition for producing a heat-sealing layer, the composition for producing an adjacent layer, and a random propylene polymer corresponding to a base film were co-extruded to obtain an unstretched laminate in which the sealant film and the base film were laminated in the order of sealant film (heat-sealing layer 10 μm / adjacent layer 10 μm) / base film 30 μm.

[0109] [Example 2] A laminate was obtained in the same manner as in Example 1, except that 40 parts by mass of rPP(AH-1) and 60 parts by mass of BPR(BH3-1) were blended to prepare a composition for producing a heat-sealing layer.

[0110] [Example 3] A laminate was obtained in the same manner as in Example 1, except that 40 parts by mass of rPP(AH-1), 30 parts by mass of PBR(BH2-1), and 30 parts by mass of BPR(BH3-1) were blended to prepare a composition for producing a heat-sealing layer.

[0111] [Comparative Example 1] A laminate was obtained in the same manner as in Example 1, except that only rPP(AH-1) was used in the heat-sealing layer and only rPP(AA-1) was used in the adjacent layer.

[0112] [Comparative Example 2] A laminate was obtained in the same manner as in Example 1, except that only rPP(AH-1) was used in the heat-sealing layer. The physical property evaluation results of the laminates of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1.

[0113]

Table 1

Claims

1. A sealant film comprising a heat-sealing layer and an adjacent layer laminated adjacent to the heat-sealing layer, wherein the sealant film satisfies the following requirements (1) and (2), the heat-sealing layer contains 30 to 90 parts by mass of a propylene-based polymer (AH) satisfying the following requirement (4) and 10 to 70 parts by mass of an olefin-based polymer (BH) satisfying the following requirement (3) (however, the total of the propylene-based polymer (AH) and the olefin-based polymer (BH) is 100 parts by mass), the adjacent layer contains 45 to 85 parts by mass of a propylene-based polymer (AA) satisfying the following requirement (4) and 15 to 55 parts by mass of an olefin-based polymer (BA) satisfying the following requirement (3) (however, the total of the propylene-based polymer (AA) and the olefin-based polymer (BA) is 100 parts by mass), a sealant film. Requirement (1) At least one outermost layer of the sealant film is the heat-sealing layer. Requirement (2) The sealant film is an unstretched film. Requirement (3) The melting point is less than 120°C or not observed. Requirement (4) The melting point is 120°C or higher and 170°C or lower.

2. wherein the olefin-based polymer (BH) contains at least one polymer selected from the group consisting of an ethylene polymer (BH1), a propylene polymer (BH2), and a 1-butene polymer (BH3), and the olefin-based polymer (BA) contains at least one polymer selected from the group consisting of an ethylene polymer (BA1), a propylene polymer (BA2), and a 1-butene polymer (BA3). The sealant film according to claim 1.

3. The sealant film according to claim 2, wherein the olefin-based polymer (BA) is the ethylene polymer (BA1), and the ethylene polymer (BA1) is at least one polymer selected from the group consisting of high-pressure low-density polyethylene, linear low-density polyethylene, and an ethylene / α-olefin copolymer.

4. The sealant film according to claim 1, wherein the heat-sealing strength when the heat-sealing layers are heat-sealed at 140°C is 15 N / 15 mm or more.

5. A laminate comprising the sealant film according to claim 1 and a base film, wherein the heat-sealing layer, the adjacent layer, and the base film are laminated in this order, and at least one outermost layer of the laminate is the heat-sealing layer. Laminate

6. The laminate according to claim 5, comprising at least one layer selected from the group consisting of a printing layer, a barrier layer, and an embossing layer

7. A package formed of the laminate according to claim 5 or 6

8. The method for manufacturing a sealant film according to claim 1, comprising a step of laminating the heat-sealing layer and the adjacent layer adjacent to each other

9. The method for manufacturing a laminate according to claim 5, comprising a step of laminating the sealant film and the base film in the order of the heat-sealing layer / the adjacent layer / the base film

10. At least one layer selected from the group consisting of the printing layer, the barrier layer, and the embossing layer is the barrier layer, The method for manufacturing a laminate according to claim 6, comprising laminating the sealant film and the base film in the order of the heat-sealing layer / the adjacent layer / the base film, and forming the barrier layer as one layer of the laminate by a metal vapor deposition method, a coating method, or a co-extrusion method

11. A laminate comprising a sealant film including a heat-sealing layer and an adjacent layer laminated adjacent to the heat-sealing layer, and a base film, The heat-sealing layer, the adjacent layer, and the base film are laminated in this order, At least one outermost layer in the laminate is the heat-sealing layer, When heat-sealing the heat-sealing layers at 140°C, the heat-sealing strength is 15 N / 15 mm or more, and the peel energy is 100 mJ or more, Laminate

Images