Laminates and packaging films

Abstract

To provide a packaging film that has good heat sealability and resistance to high-pressure steam sterilization, and a laminate from which the packaging film can be obtained. [Solution] A laminate comprising a base layer and a sealant layer, wherein the sealant layer comprises a resin composition containing a polymer (A) that satisfies specific requirements and a polymer (B) that satisfies specific requirements, the thickness of the sealant layer is 1000 μm or less, and the base layer comprises a polymer (C) that satisfies specific requirements.

Description

[Technical Field]

[0001] This invention relates to laminates and packaging films. [Background technology]

[0002] Conventionally, films formed from copolymers containing structural units derived from 4-methyl-1-pentene are known to have excellent gas permeability. For this reason, such films are widely used as packaging materials for fresh foods, for example.

[0003] As an example of such a film, Patent Document 1 proposes a film made by cast molding a resin composition containing a thermoplastic resin (A), which is a copolymer containing structural units derived from 4-methyl-1-pentene and structural units derived from α-olefins having 2 to 20 carbon atoms, and a thermoplastic resin (B), which is an olefin copolymer other than thermoplastic resin (A). In Patent Document 1, from the viewpoint of improving heat sealability, a polymer other than the polymer containing structural units derived from 4-methyl-1-pentene (specifically, thermoplastic resin (B)) is incorporated.

[0004] Patent Document 2 proposes the following laminate for the purpose of further improving the gas permeability of the film and laminated film described in Patent Document 1. A laminate comprising a substrate and a heat-seal layer in sequence toward one side in the thickness direction, wherein the heat-seal layer is a dried product of a coating composition, the coating composition contains a resin component, the resin component consists of a copolymer of 4-methyl-1-pentene and an α-olefin having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene), and / or a modified version of the copolymer, wherein in the copolymer, the content ratio of constituent units derived from 4-methyl-1-pentene is 50 mol% to 99 mol% relative to the total amount of constituent units derived from 4-methyl-1-pentene and constituent units derived from the α-olefin, the content ratio of constituent units derived from the α-olefin is 1 mol% to 50 mol%, and the oxygen permeability coefficient and carbon dioxide permeability coefficient of the laminate are 1000 cm². 3 ·mm / (m 2 A laminate that is 24 hours (atm) or longer. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-121322 [Patent Document 2] International Publication No. 2024 / 048470 [Overview of the project] [Problems that the invention aims to solve]

[0006] While the laminate described in Patent Document 2 exhibits excellent heat-sealing properties, there was room for further improvement in terms of resistance to high-pressure steam sterilization. For example, when the laminate described in Patent Document 2, particularly the laminate in which a heat-seal layer is provided across the entire surface of the base layer, and the packaging film comprising said laminate are sterilized by autoclave and applied to applications such as cell culture bags, there was a problem in that the sealant layers of the film tended to heat-seal together after high-pressure steam sterilization. Attempting to forcibly peel off a heat-sealed film can cause it to tear. Therefore, there was a need for a packaging film that maintains excellent heat-sealing properties while being resistant to heat sealing even when subjected to high-pressure steam sterilization, i.e., a film with excellent resistance to high-pressure steam sterilization, and a laminate from which such a packaging film can be obtained.

[0007] Therefore, the present invention aims to provide a packaging film that exhibits good heat sealability and resistance to high-pressure steam sterilization, and a laminate from which such a packaging film can be obtained. [Means for solving the problem]

[0008] The present invention relates, for example, to the following [1] to

[11] . [1] A laminate comprising a base layer and a sealant layer, The sealant layer comprises a resin composition containing a polymer (A) that satisfies the following requirement (AI) and a polymer (B) that satisfies the following requirement (BI), The thickness of the sealant layer is 1000 μm or less. A laminate in which the substrate layer contains a polymer (C) that satisfies the following requirements (CI). (AI): Polymer (A) contains 50 to 100 mol% of structural units derived from 4-methyl-1-pentene and 0 to 50 mol% of structural units derived from α-olefins having 5 to 20 carbon atoms (excluding 4-methyl-1-pentene). (BI): Polymer (B) contains 50-95 mol% of structural units derived from 4-methyl-1-pentene and 5-50 mol% of structural units derived from α-olefins having 2-4 carbon atoms. (CI): Polymer (C) contains 50 to 100 mol% of structural units derived from 4-methyl-1-pentene and 0 to 50 mol% of structural units derived from α-olefins having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene).

[0009] [2] When the total content of the polymer (A) and the content of the polymer (B) is 100% by mass, the content of the polymer (A) is 5 to 85% by mass, The laminate according to [1], wherein the content of the polymer (B) is 95 to 15% by mass.

[0010] [3] The laminate according to [1] or [2], wherein the polymer (A) contains 88 to 100 mol% of structural units derived from 4-methyl-1-pentene and 0 to 12 mol% of structural units derived from α-olefins having 5 to 20 carbon atoms (excluding 4-methyl-1-pentene).

[0011] [4] The laminate according to any one of [1] to [3], wherein the polymer (B) contains 50 to 87 mol% of structural units derived from 4-methyl-1-pentene and 13 to 50 mol% of structural units derived from α-olefins having 2 to 4 carbon atoms.

[0012] [5] The laminate according to any one of [1] to [4], wherein the melting point of the polymer (A) is 150°C or higher.

[0013] [6] The laminate according to any one of [1] to [5], wherein the melting point of the polymer (B) is less than 150°C.

[0014] [7] The laminate according to any one of [1] to [6], wherein the intrinsic viscosity of the polymer (A) in decalin at 135°C is 0.5 to 5.0 dl / g, and the intrinsic viscosity of the polymer (B) in decalin at 135°C is 0.5 to 5.0 dl / g.

[0015] [8] The laminate according to any one of [1] to [7], wherein when the melting point of the polymer (A) is TmA and the melting point of the polymer (B) is TmB, TmA - TmB ≥ 60°C is satisfied.

[0016] [9] The laminate according to any one of [1] to [8], wherein the content of the polymer (C) in the base material layer exceeds 50% by mass.

[0017]

[10] A packaging film comprising the laminate according to any one of [1] to [9].

[0018]

[11] A packaging bag comprising a heat seal portion in which the sealant layers in the packaging film according to

[10] are fused by heat sealing.

Advantages of the Invention

[0019] According to the present invention, it is possible to provide a packaging film having both good heat sealability and high-pressure steam sterilization resistance, and a laminate capable of obtaining the packaging film.

Modes for Carrying Out the Invention

[0020] In this specification, the descriptions of "XX or more and YY or less" and "XX to YY" representing numerical ranges mean numerical ranges including the lower limit and the upper limit, which are the endpoints, unless otherwise specified. Also, when numerical ranges are described stepwise, the upper limit and the lower limit of each numerical range can be arbitrarily combined. Furthermore, various monomers in the present invention may be derived from fossil raw materials, may be derived from organisms such as biomass, or may be mixtures thereof.

[0021] The laminate of the present invention includes a base material layer and a sealant layer. The sealant layer includes a resin composition containing a polymer (A) and a polymer (B). The base material layer includes a polymer (C).

[0022] [Sealant Layer] <Polymer (A)> Since the resin composition contains the polymer (A), the laminate and the packaging film including the sealant layer have good high-pressure steam sterilization resistance.

[0023] Polymer (A) satisfies the following requirement (AI). In the following description, the constituent unit derived from 4-methyl-1-pentene may be referred to as "constituent unit (ai)". Similarly, the constituent unit derived from α-olefins having 5 to 20 carbon atoms (excluding 4-methyl-1-pentene) may be referred to as "constituent unit (a-ii)".

[0024] <Requirements (AI)> Polymer (A) contains 50 to 100 mol% of structural units derived from 4-methyl-1-pentene and 0 to 50 mol% of structural units derived from α-olefins having 5 to 20 carbon atoms (excluding 4-methyl-1-pentene).

[0025] The content (UA1) of constituent unit (ai) in polymer (A) is preferably 88 to 100 mol%, more preferably 93 to 99 mol%, and even more preferably 95 to 98 mol% (provided that the sum of the content of constituent unit (i) and the content of constituent unit (ii) is 100 mol%). The content (UA2) of constituent units (a-ii) in polymer (A) is preferably 0 to 12 mol%, more preferably 1 to 7 mol%, and even more preferably 2 to 5 mol% (provided that the sum of the content of constituent unit (i) and the content of constituent unit (ii) is 100 mol%). UA1 and UA2 are determined by the method described in the examples. Polymers (A) in which UA1 and UA2 are within the above range exhibit excellent heat resistance and high-pressure steam sterilization resistance. Therefore, laminates containing a resin composition containing polymers (A) in which UA1 and UA2 are within the above range also tend to exhibit excellent heat resistance and high-pressure steam sterilization resistance.

[0026] The α-olefins that lead to the constituent units (a-ii) are, for example, linear α-olefins. Examples of α-olefins that lead to the constituent units (a-ii) include 1-pentene, 1-hexene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, and 1-eicosene. Among these, linear α-olefins having 6 to 18 carbon atoms are preferred from the viewpoint of heat resistance and resistance to high-pressure steam sterilization. Specifically, preferred α-olefins for deriving the constituent units (a-ii) are 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-heptadecene, and 1-octadecene, with 1-decene, 1-hexadecene, and 1-octadecene being particularly preferred.

[0027] The constituent units (a-ii) may be derived from only one selected from the group consisting of α-olefins having 5 to 20 carbon atoms, or from two or more selected from the group consisting of α-olefins having 5 to 20 carbon atoms.

[0028] A preferred embodiment of polymer (A) is a copolymer consisting only of structural units (ai) and structural units (a-ii). In this case, the sum of the content of structural unit (ai) and structural unit (a-ii) is 100 mol%.

[0029] Another preferred embodiment of polymer (A) is a copolymer that, in addition to structural units (ai) and structural units (a-ii), contains a small amount, specifically 10 mol% or less, preferably 5 mol% or less, and more preferably 3 mol% or less, of structural units derived from 4-methyl-1-pentene and other polymerizable monomers other than α-olefins having 5 to 20 carbon atoms, in an amount that does not impair the purpose of the present invention. The other polymerizable monomer may be one type or two or more types.

[0030] Other preferred examples of polymerizable monomers include vinyl compounds having a cyclic structure such as styrene, vinylcyclopentane, vinylcyclohexane, and vinylnorbornane; vinyl esters such as vinyl acetate; unsaturated organic acids or their derivatives such as maleic anhydride; conjugated dienes such as butadiene, isoprene, pentadiene, and 2,3-dimethylbutadiene; 1,4-hexadiene, 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, and 7-methyl-1,6-octadiene. Examples of non-conjugated polyenes include ene, dicyclopentadiene, cyclohexadiene, dicyclooctadiene, methylenenorbornene, 5-vinyl-2-norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, and 2-propenyl-2,2-norbornadiene.

[0031] Here, if polymer (A) contains structural units derived from other polymerizable monomers, it is preferable that the total content of structural units (a-ii) and structural units derived from other polymerizable monomers satisfies the range of content of structural units (a-ii). In this case, the total content of structural units (ai), structural units (a-ii), and structural units derived from other polymerizable monomers is 100 mol%.

[0032] <Melting point of polymer (A)> The melting point (TmA) of polymer (A), as measured by differential scanning calorimeter (DSC) using the method described in the examples below, is preferably 150°C or higher. When the melting point (TmA) of polymer (A) is within the above range, it exhibits good heat resistance and resistance to high-pressure steam sterilization. The melting point (TmA) is more preferably 180°C or higher, and even more preferably 200°C or higher. The upper limit of the melting point (TmA) is not particularly limited, but for example, it is 500°C or lower, preferably 280°C or lower. The melting point (TmA) value tends to depend on the stereoregularity of polymer (A) and the content of constituent units (a-ii) in polymer (A). Therefore, the melting point (TmA) can be adjusted by using the olefin polymerization catalyst described later and by controlling the content of constituent units (a-ii).

[0033] <Intrinsic viscosity of polymer (A) in decalin at 135°C> The intrinsic viscosity [η] of polymer (A), measured in decalin at 135°C by the method described in the examples below, is preferably 0.5 to 5.0 dl / g, and more preferably 1.0 to 3.0 dl / g. Polymers (A) whose intrinsic viscosity [η] falls within the aforementioned range exhibit good fluidity during molding. The intrinsic viscosity [η] can be adjusted, for example, by the amount of hydrogen added during the polymerization process when producing polymer (A).

[0034] The melt flow rate (MFR) of polymer (A), measured in accordance with ASTM D1238 at 260°C under a 5kg load, is preferably in the range of 1 to 100 g / 10 min, more preferably 5 to 50 g / 10 min, and even more preferably 7 to 30 g / 10 min. An MFR within this range is preferable in terms of fluidity during molding.

[0035] According to the method described in the examples below, the heat of fusion (ΔHm) at the melting peak (Tm) of polymer (A), measured by differential scanning calorimeter (DSC), is preferably 5 to 60 J / g, more preferably 15 to 45 J / g. A heat of fusion within this range is preferable in terms of processability to film.

[0036] <Polymer (B)> Because the resin composition contains polymer (B), the laminate and packaging film having the sealant layer have good heat-sealing properties. Polymer (B) satisfies the following requirement (BI). In the following description, the structural unit derived from 4-methyl-1-pentene may be referred to as "structural unit (bi)". Similarly, the structural unit derived from α-olefins having 2 to 4 carbon atoms may be referred to as "structural unit (b-iii)".

[0037] <Requirements (BI)> Polymer (B) contains 50 to 95 mol% of structural units derived from 4-methyl-1-pentene and 5 to 50 mol% of structural units derived from α-olefins having 2 to 4 carbon atoms.

[0038] The content (UB1) of constituent unit (bi) in polymer (B) is preferably 50 to 90 mol%, more preferably 50 to 87 mol%, even more preferably 60 to 87 mol%, and particularly preferably 70 to 87 mol% (provided that the sum of the content of constituent unit (bi) and the content of constituent unit (b-iii) is 100 mol%). The content (UB3) of constituent unit (b-iii) in polymer (B) is preferably 10 to 50 mol%, more preferably 13 to 50 mol%, even more preferably 13 to 40 mol%, and particularly preferably 13 to 30 mol% (provided that the sum of the content of constituent unit (bi) and the content of constituent unit (b-iii) is 100 mol%). UB1 and UB3 are determined by the method described in the examples. Polymer (B) in which UB1 and UB3 are within the above range exhibits excellent heat resistance and heat seal strength. Therefore, a sealant layer containing a resin composition containing polymer (B) in which UB1 and UB3 are within the above range also tends to exhibit excellent heat resistance and heat seal strength.

[0039] Examples of α-olefins used to derive the constituent unit (b-iii) include ethylene, propylene, and 1-butene, with propylene being preferred. The constituent unit (b-iii) may be derived from only one selected from the group consisting of α-olefins having 2 to 4 carbon atoms, or it may be derived from two or more selected from the group consisting of α-olefins having 2 to 4 carbon atoms.

[0040] A preferred embodiment of polymer (B) is a copolymer consisting only of structural unit (bi) and structural unit (b-iii). In this case, the sum of the content of structural unit (bi) and structural unit (b-iii) is 100 mol%.

[0041] Another preferred embodiment of polymer (B) is a copolymer that, in addition to structural units (bi) and (b-iii), contains a small amount, specifically 10 mol% or less, preferably 5 mol% or less, and more preferably 3 mol% or less, of structural units derived from 4-methyl-1-pentene and other polymerizable monomers other than α-olefins having 2 to 4 carbon atoms, in an amount that does not impair the purpose of the present invention. The other polymerizable monomer may be one type or two or more types.

[0042] Preferred examples of such other polymerizable monomers include monomers similar to the other polymerizable monomers in polymer (A).

[0043] Here, if polymer (B) contains structural units derived from other polymerizable monomers, it is preferable that the total content of structural unit (b-iii) and structural units derived from other polymerizable monomers satisfies the range of content of structural unit (b-iii). In this case, the total content of structural unit (bi), structural unit (b-iii), and structural units derived from other polymerizable monomers is 100 mol%.

[0044] <Melting point of polymer (B)> The melting point (TmB) of polymer (B), as measured by differential scanning calorimeter (DSC) using the method described in the examples below, is preferably less than 150°C. When the melting point (TmB) of polymer (B) is within the above range, it exhibits excellent heat sealability. The melting point (TmB) is more preferably 145°C or less, and even more preferably 140°C or less. From the viewpoint of heat resistance and heat sealability, the melting point (TmB) is preferably 100°C or higher, and more preferably 120°C or higher. The melting point (TmB) tends to depend on the stereoregularity of polymer (B) and the content of constituent units (b-iii) in polymer (B). Therefore, the melting point (TmB) can be adjusted by using the olefin polymerization catalyst described later and by controlling the content of constituent units (b-iii).

[0045] When the melting point of polymer (A) is TmA and the melting point of polymer (B) is TmB, TmA-TmB is preferably 60°C or higher (TmA-TmB≧60°C), more preferably 70°C or higher, even more preferably 80°C or higher, and particularly preferably 85°C or higher. When TmA-TmB is 60°C or higher, a good balance is achieved between heat sealability and resistance to high-pressure steam sterilization, and high-pressure steam sterilization resistance is particularly good. TmA-TmB is, for example, 150°C or lower.

[0046] <Intrinsic viscosity of polymer (B) in decalin at 135°C> The intrinsic viscosity [η] of polymer (B), measured in decalin at 135°C by the method described in the examples below, is preferably 0.5 to 5.0 dl / g, more preferably 1.0 to 3.0 dl / g, and even more preferably 1.0 to 2.0 dl / g. Polymers (B) whose intrinsic viscosity [η] falls within the aforementioned range exhibit good fluidity during molding. The intrinsic viscosity [η] can be adjusted, for example, by the amount of hydrogen added during the polymerization process when producing polymer (B).

[0047] The melt flow rate (MFR) of polymer (B), measured in accordance with ASTM D1238 at 230°C and under a 2.16 kg load, is preferably in the range of 1 to 100 g / 10 min, more preferably 1 to 50 g / 10 min, and even more preferably 5 to 20 g / 10 min. An MFR within this range is preferable in terms of fluidity during molding.

[0048] As described in the examples below, the heat of fusion (ΔHm) at the melting peak (Tm) of polymer (B), measured by differential scanning calorimeter (DSC), is preferably 1 to 30 J / g, more preferably 5 to 15 J / g. A heat of fusion within this range is preferable in terms of heat sealability.

[0049] <Method for producing polymer (A)> Polymer (A) can be obtained by polymerizing polymerizable monomers such as 4-methyl-1-pentene, which will be the constituent units of polymer (A), in the presence of an olefin polymerization catalyst, using a known method.

[0050] Examples of olefin polymerization catalysts that can be used in the production of polymer (A) include Ziegler-Natta catalysts and metallocene catalysts. A preferred Ziegler-Natta catalyst is, for example, the solid titanium catalyst component [A-9] described in International Publication No. 2006 / 054613. Other preferred metallocene catalysts include, for example, the metallocene catalysts described in International Publication No. 01 / 53369, International Publication No. 01 / 27124, Japanese Patent Publication No. 3-193796, Japanese Patent Publication No. 02-41303, International Publication No. 06 / 025540, or International Publication No. 2014 / 123212. Furthermore, polymer (A) can also be obtained by polymerizing polymerizable monomers such as 4-methyl-1-pentene, which form the constituent units of polymer (A), based on the method described in International Publication No. 2004 / 87775.

[0051] Polymer (A) may be a polymer prepared to satisfy requirement (AI) by heat-treating a polymer that has been produced using the catalyst, etc., in an extruder or mixer, etc. Polymer (A) may be a polymer prepared to satisfy requirement (AI) by heat-treating a commercially available 4-methyl-1-pentene polymer in an extruder or mixer. An example of such a commercially available product is TPX manufactured by Mitsui Chemicals, Inc.

[0052] <Method for producing polymer (B)> Polymer (B) can be obtained by polymerizing polymerizable monomers such as 4-methyl-1-pentene, which form the constituent units of polymer (B), using the same method as for producing polymer (A). Alternatively, polymer (B) may be obtained by heat-treating a polymer that has already been produced, similar to polymer (A). Polymer (B) may be a commercially available 4-methyl-1-pentene polymer. An example of such a commercially available product is the absortomer manufactured by Mitsui Chemicals, Inc.

[0053] Polymer (A) may be a modified polymer obtained by graft-modifying the unmodified polymer (A) with a graft component. The same applies to polymer (B). A method for graft-modifying polymer (A) or polymer (B) with a graft component includes, for example, first dissolving the unmodified polymer (A) or polymer (B) in a known organic solvent (e.g., toluene), then adding the graft component and a radical polymerization initiator, mixing them, and heating (specifically, melt-mixing).

[0054] Examples of graft components include hydroxyl group-containing ethylenically unsaturated compounds, amino group-containing ethylenically unsaturated compounds, unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, vinyl ester compounds, and thiol group-containing ethylenically unsaturated compounds. Preferred graft components include unsaturated carboxylic acids and / or unsaturated carboxylic acid anhydrides. The graft component is preferably an unsaturated carboxylic acid anhydride, and more preferably maleic anhydride. The graft component may be used alone or in combination of two or more types.

[0055] Examples of radical polymerization initiators include organic peroxides and organic peresters. A single radical polymerization initiator may be used, or two or more may be used in combination.

[0056] <Resin composition> The resin composition comprises polymer (A) and polymer (B). When the sum of the content of polymer (A) and polymer (B) in the resin composition is 100% by mass, preferably the content of polymer (A) is 5 to 85% by mass and the content of polymer (B) is 95 to 15% by mass. More preferably, the content of polymer (A) is 25 to 80% by mass and the content of polymer (B) is 75 to 20% by mass. Even more preferably, the content of polymer (A) is 30 to 80% by mass and the content of polymer (B) is 70 to 20% by mass. Particularly preferably, the content of polymer (A) is 40 to 75% by mass and the content of polymer (B) is 60 to 25% by mass. When the content of polymer (A) and polymer (B) are within the aforementioned range, a good balance is achieved between heat sealability and resistance to high-pressure steam sterilization, and in particular, resistance to high-pressure steam sterilization is improved.

[0057] <Additives> The resin composition may optionally contain additives, provided that they do not impair the effects of the present invention. Examples of additives include leveling agents, defoaming agents, antioxidants, heat stabilizers, ultraviolet absorbers, plasticizers, surfactants, pigments, thixotropes, thickeners, tackifiers, surface modifiers, anti-settling agents, weathering agents, pigment dispersants, antistatic agents, fillers, fungicides, and silane coupling agents. Additives may be used individually or in combination of two or more types.

[0058] <Method for producing resin compositions> The resin composition is obtained by mixing the polymer (A) and the copolymer (B) in the specified proportions. The resin composition can be prepared by various known methods, such as dry blending the above components using a Henschel mixer, tumbler blender, or V-blender; melt-kneading the dry-blended components using a single-screw extruder, twin-screw extruder, or Banbury mixer; and stirring and mixing the components in the presence of a solvent.

[0059] <Method for manufacturing a heat-sealed layer> The method for manufacturing the heat seal layer is not particularly limited, and known molding methods can be employed. Examples of such molding methods include extrusion molding methods such as the T-die method and the extrusion tubular method (inflation method), solution casting, and calendering.

[0060] [Base material layer] <Polymer (C)> Polymer (C) satisfies the following requirements (CI). In the following description, the constituent unit derived from 4-methyl-1-pentene may be referred to as "constituent unit (ci)". Similarly, the constituent unit derived from α-olefins having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene) may be referred to as "constituent unit (c-iv)".

[0061] <Requirements (CI)> Polymer (A) contains 50 to 100 mol% of structural units derived from 4-methyl-1-pentene and 0 to 50 mol% of structural units derived from α-olefins having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene).

[0062] The content (UC1) of constituent units (ci) in polymer (C) is preferably 88 to 100 mol%, more preferably 93 to 99 mol%, and even more preferably 95 to 98 mol% (provided that the sum of the content of constituent units (ci) and the content of constituent units (c-iv) is 100 mol%). The content of constituent units (c-iv) (UC4) in polymer (C) is preferably 0 to 12 mol%, more preferably 1 to 7 mol%, and even more preferably 2 to 5 mol% (provided that the sum of the content of constituent units (ci) and the content of constituent units (c-iv) is 100 mol%). UC1 and UC4 are determined by the method described in the examples. Polymers (C) in which UC1 and UC4 are within the aforementioned ranges exhibit excellent heat resistance. Therefore, laminates comprising a substrate layer containing polymers (C) in which UC1 and UC4 are within the aforementioned ranges also tend to exhibit excellent heat resistance.

[0063] The α-olefins that derive the constituent units (c-iv) are, for example, linear α-olefins. Examples of α-olefins that derive the constituent units (c-iv) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-heptadecene, 1-octadecene, and 1-eicosene. Among these, linear α-olefins having 6 to 18 carbon atoms are preferred from the viewpoint of heat resistance. Specifically, preferred α-olefins for deriving the constituent units (c-iv) are 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-heptadecene, and 1-octadecene, with 1-hexadecene and 1-octadecene being particularly preferred.

[0064] The constituent units (c-iv) may be derived from only one selected from the group consisting of α-olefins having 2 to 20 carbon atoms, or from two or more selected from the group consisting of α-olefins having 2 to 20 carbon atoms.

[0065] A preferred embodiment of polymer (C) is a copolymer consisting only of structural units (ci) and structural units (c-iv). In this case, the sum of the content of structural units (ci) and structural units (c-iv) is 100 mol%.

[0066] Another preferred embodiment of polymer (C) is a copolymer that, in addition to structural units (ci) and (c-iv), contains a small amount, specifically 10 mol% or less, preferably 5 mol% or less, and more preferably 3 mol% or less, of structural units derived from 4-methyl-1-pentene and other polymerizable monomers other than α-olefins having 2 to 20 carbon atoms, in an amount that does not impair the purpose of the present invention. The other polymerizable monomer may be one type or two or more types.

[0067] Preferred examples of such other polymerizable monomers include monomers similar to the other polymerizable monomers in polymer (A).

[0068] Here, if polymer (C) contains structural units derived from other polymerizable monomers, it is preferable that the total content of structural units (c-iv) and structural units derived from other polymerizable monomers satisfies the range of content of structural units (c-iv). In this case, the total content of structural units (ci), structural units (c-iv), and structural units derived from other polymerizable monomers is 100 mol%.

[0069] <Melting point of polymer (C)> The melting point (TmC) of polymer (C), as measured by differential scanning calorimeter (DSC) using the method described in the examples below, is preferably 150°C or higher. When the melting point (TmC) of polymer (C) is within the above range, it exhibits good heat resistance. The melting point (TmC) is more preferably 180°C or higher, and even more preferably 200°C or higher. There is no particular upper limit to the melting point (TmC), but for example, it is 500°C or lower, preferably 280°C or lower. The melting point (TmC) value tends to depend on the stereoregularity of the polymer (C) and the content of the constituent units (c-iv) in the polymer (C). Therefore, the melting point (TmC) can be adjusted by using the olefin polymerization catalyst described later and by controlling the content of the constituent units (c-iv).

[0070] <Intrinsic viscosity of polymer (C) in decalin at 135°C> The intrinsic viscosity [η] of polymer (C), measured in decalin at 135°C by the method described in the examples below, is preferably 0.5 to 5.0 dl / g, and more preferably 1.0 to 3.0 dl / g. Polymers (C) whose intrinsic viscosity [η] falls within the aforementioned range exhibit good fluidity during molding. The intrinsic viscosity [η] can be adjusted, for example, by the amount of hydrogen added during the polymerization process when producing polymer (C).

[0071] The melt flow rate (MFR) of polymer (C) measured in accordance with ASTM D1238 at 260°C under a 5kg load is preferably in the range of 1 to 100 g / 10 min, more preferably 5 to 50 g / 10 min, and even more preferably 10 to 30 g / 10 min. An MFR within this range is preferable in terms of fluidity during molding.

[0072] In the method described in the examples below, the heat of fusion (ΔHm) at the melting peak (Tm) of the polymer (C), measured by differential scanning calorimeter (DSC), is preferably 5 to 50 J / g, more preferably 10 to 30 J / g. A heat of fusion within this range is preferable in terms of processability to the film.

[0073] <Method for manufacturing the base layer> The method for manufacturing the base layer is not particularly limited, and known molding methods can be employed. Examples of such molding methods include extrusion molding methods such as the T-die method and the extrusion tubular method (inflation method), solution casting, and calendering. Polymer (C) can be produced in the same manner as polymer (A) or polymer (B). The same polymer as polymer (A) or polymer (B) may be used as polymer (C).

[0074] The base layer may contain other materials and additives as long as they do not impair the effects of the present invention. Other materials include, for example, polyolefin resins such as ethylene polymers, propylene polymers, butene polymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, and polyolefin thermoplastic elastomers, as well as porous substrates such as paper, fabrics, knits, and nonwoven fabrics. Examples of additives include leveling agents, defoaming agents, antioxidants, heat stabilizers, UV absorbers, plasticizers, surfactants, pigments, thixotropes, thickeners, tackifiers, surface modifiers, anti-settling agents, weathering agents, pigment dispersants, antistatic agents, fillers, fungicides, and silane coupling agents. Other materials and additives may be used individually or in combination of two or more. The content of the polymer (C) in the base layer is preferably more than 50% by mass, and more preferably 80 to 100% by mass, from the viewpoint of gas permeability of the laminate and packaging film.

[0075] [Laminated structure] The laminate of the present invention comprises a base layer and a sealant layer. The layer configuration of the laminate is not particularly limited and can be set as appropriate depending on the application. The laminate may comprise one base layer and one sealant layer, or it may comprise multiple base layers or sealant layers. When the laminate comprises multiple sealant layers or base layers, the multiple sealant layers or base layers may be identical or different from one another. When there is only one sealant layer, the sealant layers can be reliably bonded together by heat sealing when manufacturing packaging bags, etc., as described later.

[0076] The laminate preferably comprises only the base layer and the sealant layer, and more preferably only one base layer and one sealant layer. The sealant layer is preferably in contact with the substrate layer. Furthermore, the sealant layer is preferably provided over the entire surface of the substrate layer. From the viewpoint of being able to select a wide range of heat-sealable sealing temperatures, it is preferable that the sealant layer be at least one outermost layer of the laminate.

[0077] The thickness of the sealant layer is 1000 μm or less. A sealant layer thickness of 1000 μm or less provides good heat sealability. From the viewpoint of heat sealability, the thickness of the sealant layer is preferably 100 μm or less, more preferably 50 μm or less. From the viewpoint of heat seal strength and productivity, the thickness of the sealant layer is preferably 10 μm or more. The thickness of the substrate layer is preferably 10 to 500 μm, more preferably 15 to 250 μm, and even more preferably 20 to 100 μm. The ratio of the thicknesses of each layer in the laminate is not particularly limited and can be set as appropriate depending on the application.

[0078] [Method for manufacturing laminates] The method for manufacturing the laminate is not particularly limited, and known methods such as extrusion casting, extrusion lamination, and dry lamination can be employed. The laminate of the present invention can be manufactured, for example, by the following method. However, the method for manufacturing the laminate of the present invention is not limited thereto.

[0079] First, using a co-extrusion molding machine connected to a T-die, polymer (C), which is a resin material to be used for the base layer, is put into the hopper of one of the extruders of the co-extrusion molding machine, and polymer (A) and polymer (B), which are resin materials to be used for the sealant layer, or the resin composition, is put into the hopper of the other extruder of the co-extrusion molding machine. Then, the cylinder temperature is set to 200-300°C and the die temperature is set to 200-300°C to melt each resin material. By co-extruding a molten polymer (C) and a resin composition containing molten polymers (A) and (B) from a T-die, and then cooling and solidifying the mixture at a cast roll temperature of 20 to 100°C, a laminate in which the substrate layer and the sealant layer are laminated can be obtained. The substrate layer and the sealant layer may be manufactured separately, and then the two layers may be laminated together to produce the laminate.

[0080] [Applications (Packaging Film)] The laminate of the present invention exhibits excellent heat-sealability and resistance to high-pressure steam sterilization, and therefore its applications are not particularly limited and it can be used in a wide range of applications. The laminate can be suitably used, for example, as a packaging film. Examples of applications for the packaging film include packaging materials for food (e.g., meat, processed fish, vegetables, fruits, fermented foods, retort foods, confectionery, pharmaceuticals, bulbs, seeds, mushrooms), freshness-preserving films, wrap films, medical packaging materials, pharmaceutical packaging materials, packaging bags for culturing microorganisms and cells, blood transfusion bags, blood bags, cell examination films, heat-resistant vacuum-formed containers, prepared food containers, lids for prepared foods, and baking cartons. Examples of packaging bags for culturing microorganisms and cells include cell culture bags and packaging bags for mushroom cultivation. Such packaging films comprise the laminate. Therefore, the packaging film exhibits excellent heat-sealability and resistance to high-pressure steam sterilization.

[0081] The packaging film is used, for example, in a packaging bag. The packaging bag has a heat-sealed portion where the sealant layers of the packaging film are fused together by heat sealing. The packaging bag may or may not have an opening. "Packaging bags with an opening" refers to packaging bags that have a so-called bag opening, and more specifically, packaging bags in which at least a portion of the periphery of the packaging bag has a section where the packaging films are not fused together, and through that section, the contents can be contained in or removed. "Packaging bags without an opening" refers to packaging bags that do not have a so-called bag opening. Specifically, it refers to packaging bags in which the packaging films are fused together at all edges, or packaging bags in which at least a portion of the edges of the packaging bag is not fused together, and in which a component other than the packaging film is provided at that location. The component other than the packaging film may be a component through which the contents can be contained or removed. Examples of such components include a spout in a pouch and a port in a cell culture bag, which will be described later. A packaging bag in which at least a portion of the periphery of the packaging bag is not fused together with the other packaging film, and where such portion is not large enough to contain or remove the contents, is considered a packaging bag without an opening.

[0082] The aforementioned packaging bag may or may not have a portion from which the contents can be contained or removed.

[0083] Examples of methods for manufacturing a packaging bag with an opening include: overlapping two packaging films so that their sealant layers face each other and bonding them together by heat-sealing a portion of the periphery from the outer surface; heat-sealing one end of a tubular packaging film obtained by the inflation method; and folding a rectangular packaging film so that its sealant layers overlap and heat-sealing two sides perpendicular to the folded edge.

[0084] The aforementioned packaging bag can be used, for example, for culturing microorganisms and cells. Examples of microorganisms include fungi, bacteria, unicellular algae, viruses, and protozoa. Examples of fungi include mushrooms, molds, and yeasts. Examples of bacteria include Bacillus subtilis, Escherichia coli, Staphylococcus, Enterococcus, Pseudomonas aeruginosa, Shigella, Corynebacterium, and Haemophilus influenzae. Examples of cells include animal or plant cells, tissue cultures, fusion cells (including hybridomas) obtained by genetic engineering techniques, and dedifferentiated cells. The animal or plant cells may be stem cells, dedifferentiated cells, or differentiated cells. The aforementioned packaging bag can also be used, for example, for culturing transformed organisms.

[0085] Examples of the culture methods include shaking culture and static culture. Static culture is preferred because it allows for miniaturization of the culture vessel without the need for a shaking device, reduces noise caused by shaking, and minimizes the risk of contents leaking out during shaking. A method for culturing microorganisms and cells using the aforementioned packaging bag includes, for example, a step of statically culturing microorganisms and cells using the aforementioned packaging bag. There are no restrictions on the culture medium used; you should select a medium that suits the characteristics of the microorganisms and cells.

[0086] The packaging bag is used, for example, as a packaging bag for mushroom cultivation. The packaging bag for mushroom cultivation is obtained, for example, by heat-sealing the lower end of a tubular packaging film obtained by the inflation method. The upper end of the packaging bag for mushroom cultivation is open, and the lower end is sealed. Both sides of the packaging bag for mushroom cultivation may be folded inward, creating a so-called gusset fold. The packaging bag for mushroom cultivation may be provided with, for example, ventilation holes and filters. The ventilation holes and filters do not constitute openings.

[0087] The aforementioned packaging bag is used, for example, as a cell culture bag. A cell culture bag is obtained by overlapping two packaging films so that the sealant layers face each other, and then heat-sealing at least a portion of the periphery from the outer surface side to bond the packaging films together. The cell culture bag may or may not have a port. A cell culture bag with a port can be manufactured, for example, by inserting the port into a packaging bag having an opening, heating and bonding the attachment portion of the port to the packaging film around the attachment portion, and then bonding the packaging film that is not bonded to the port at the opening. A port refers to a tubular member that connects the inside of the bag to the outside of the bag, allowing the flow of culture medium and cells. A cell culture bag with a port falls under the category of a "packaging bag without an opening" because at least a portion of the peripheral edge of the packaging bag has areas where the packaging films are not fused together, and these areas have a port, which is a member other than the packaging film.

[0088] If the cell culture bag has ports, there may be one or more ports. If the cell culture bag has multiple ports, for example, the ports are spaced apart. When bonding the attachment portion of the port to the packaging film around the periphery of the attachment portion, a heating mold may be used. The heating mold is, for example, a pair of symmetrical, heatable molds with recesses that correspond to the shape of the attachment portion of the port.

[0089] For example, in applications such as packaging bags for mushroom cultivation and cell culture bags, the packaging bags may be sterilized by high-pressure steam using an autoclave or the like.

[0090] The autoclaving process may be performed on packaging bags with an opening or on packaging bags without an opening. Autoclaving may be performed on packaging bags with an opening before the contents are placed inside, or on packaging bags after the contents have been placed inside and the packaging bags have been sealed. Autoclaving may be performed on the packaging bags while they have an opening, and then again after the packaging bags have been sealed. Alternatively, autoclaving may be performed after the contents have been placed inside but before the packaging bags have been sealed. In the case of the cell culture bags, for example, autoclaving may be performed before inserting the port, and then again after inserting the port. Autoclaving may also be performed on sealed packaging bags that do not contain any contents.

[0091] Since the packaging bag comprises the laminate, heat fusion between sealant layers due to high-pressure steam sterilization is unlikely to occur, especially when a sealant layer is provided across the entire inside surface of the bag. [Examples]

[0092] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the spirit of the invention. Table 1 shows the copolymers used in the examples and comparative examples. Various physical properties were measured by the following methods.

[0093] [composition] The content (mol%) of the constituent units derived from 4-methyl-1-pentene and the comonomer in the polymer is as follows: 13 The measurement was performed by 13C-NMR. The measurement conditions were as follows:

[0094] ~Measurement Conditions~ Measurement equipment: Nuclear magnetic resonance spectrometer (ECP500 model, manufactured by JEOL Ltd.) Observation nucleus: 13 C(125MHz) Sequence: Single-pulse proton decoupling Pulse width: 4.7 μs (45° pulse) Repeat time: 5.5 seconds Total number of times: 10,000 or more Solvent: Orthodichlorobenzene / deuterated benzene (volume ratio: 80 / 20) mixed solvent Sample concentration: 55 mg / 0.6 mL Measurement temperature: 120℃ Chemical shift baseline: 27.50 ppm

[0095] [Intrinsic viscosity [η]] The intrinsic viscosity [η] of copolymers (A-1), (A-2), and (B-1) was measured using an Ubbelohde viscometer in decalin solvent at 135°C. Specifically, approximately 20 mg of powdered copolymer was dissolved in 25 mL of decalin, and the specific viscosity ηsp was measured in an oil bath at 135°C using an Ubbelohde viscometer. After diluting this decalin solution by adding 5 mL of decalin, the specific viscosity ηsp was measured in the same manner as above. This dilution procedure was repeated two more times, and the intrinsic viscosity [η] (unit: dl / g) was determined by extrapolating the concentration (C) to 0 as ηsp / C (see Equation 1 below). [η]=lim(ηsp / C) (C→0) (Equation 1)

[0096] [Melt Flow Rate (MFR)] The melt flow rates (MFRs) of copolymers (A-1) and (A-2) were measured in accordance with ASTM D1238, under conditions of a measurement temperature of 260°C and a load of 5 kg. The MFR of copolymer (B-1) was measured in the same manner as that of copolymers (A-1) and (A-2), except that the measurement temperature was changed to 230°C and the load to 2.16 kg. In all cases, the unit is g / 10 min.

[0097] [Melting point (Tm) and heat of fusion (ΔHm)] Using a DSC measuring device (model number: DSC7000C) manufactured by Seiko Instruments Inc., approximately 5 mg of the sample was placed in an aluminum measuring pan and heated to 280°C at a rate of 10°C / min. After holding at 280°C for 5 minutes, the temperature was lowered to 20°C at a rate of 10°C / min. After holding at 20°C for 5 minutes, the temperature was raised to 280°C at a rate of 10°C / min. The peak of the crystal melting peak in the DSC curve observed during the second heating was defined as the melting point (Tm). The heat of fusion (ΔHm) was calculated from the integrated value of this crystal melting peak.

[0098] [Heat seal strength] Two strips measuring 150 mm wide x 50 mm long were prepared as test specimens, each made by cutting the 50 μm thick film obtained in the example into strips. Next, the two prepared test specimens were placed on top of each other so that the sealant layers faced each other. Then, using a heat seal tester (Hand Impulse T-30, manufactured by Techno Impulse Co., Ltd.), the two strips were heat-sealed by applying current for 1 second under the condition of a seal width of 2 mm, followed by holding them down for 5 seconds. Next, the heat-sealed film was removed from the testing machine and cut into 15mm wide strips. These 15mm wide heat-sealed films were then pulled and peeled off at a 180° angle to the heat-sealed surface of the film using a seal strength tester (AG-200NX, manufactured by Shimadzu Corporation) at a tensile speed of 300mm / min and a temperature of 23°C. The maximum value of the strength (peel strength) at this time was measured and defined as the heat seal strength (unit: N / 15mm). In cases where the film stretched without peeling, the maximum value of the detected strength was defined as the heat seal strength. The heat seal strength was measured for five test pieces, and the average value was calculated.

[0099] [Transparency (Haze)] HAZE was measured in accordance with JIS K7136-1 using the film with a thickness of 50 μm obtained in the examples as a test piece. A D65 light source was used for the measurement. It can be said that the lower the HAZE value, the better the transparency.

[0100] [Gas Permeability] The oxygen transmission coefficient of the film (unit: cm 3 ·mm / (m 2 ·24h·atm)) and the water vapor transmission coefficient (unit: g·mm / (m 2 ·24h)) were measured by the following method. The film with a thickness of 50 μm obtained in the examples was cut into a shape of width 50 mm × length 50 mm and used as a test piece. The oxygen transmission coefficient was measured in accordance with JIS K7126-1 using a differential pressure method gas permeability measuring device BT-3 (manufactured by Toyo Seiki Seisakusho Co., Ltd.) under the conditions of a test temperature of 23°C and a test humidity of 0%RH. Using the cell attached to the above BT-3 with a measurement part of φ30 mm, the transmission area of the film was set to 7.07 cm 2 and measured without attaching an aluminum mask. It can be said that the larger the value of the oxygen transmission coefficient, the better the gas permeability.

[0101] The water vapor transmission coefficient was measured in accordance with JIS K7129B isobaric method (MOCON method) using PERMATRAN W3 / 33 (manufactured by MOCON) under the conditions of a test temperature of 23°C and a test humidity of 90%RH with the measurement area of the film set to 50 cm 2 and measured. It can be said that the larger the value of the water vapor transmission coefficient, the better the gas permeability (moisture permeability).

[0102] [High-pressure Steam Sterilization Resistance] Two strips measuring 150 mm wide x 50 mm long were prepared as test specimens, cut from the 50 μm thick film obtained in the examples. Next, the two prepared test specimens were stacked so that the sealant layers faced each other, and then autoclaved at 121°C for 30 minutes using an LSX-300 autoclave (manufactured by Tommy Industries Co., Ltd.). The thermal fusion of the film after autoclaving was evaluated according to the following criteria. The evaluation results are shown in Table 2. [Evaluation Criteria] ◎: The parts where the two films meet are not heat-fused. ○: The areas where the two films meet (contact areas) are heat-fused, but the proportion of the heat-fused area is less than 10% of the entire contact area. ×: The area where the two films meet is heat-fused, and the proportion of the heat-fused area is 10% or more of the total contact area.

[0103] [Static culture evaluation] As a test specimen, one sheet of 50 μm thick film obtained in the examples and comparative examples was cut to A4 size (long side 297 mm, short side 210 mm). Next, the prepared test specimen was folded in half with the sealant layer facing inward and the fold parallel to the short side. The folded test specimen had a long side of 210 mm and a short side of approximately 148 mm (297 mm / 2). Subsequently, using a heat seal tester (Hand Impulse T-30, manufactured by Techno Impulse Co., Ltd.), the specimen was heat-sealed to divide it into four vertical sections to obtain a packaging bag suitable for culture. The packaging bag contained four sections, each with a long side of 148 mm and a short side of approximately 52 mm (210 mm / 4). Each section had an opening on one short side, and the other short side was the side that had been the fold when the test specimen was folded in half. Heat sealing was performed by applying an electric current for 1 second under the condition of a seal width of 2 mm, followed by holding the seal down for 5 seconds. The resulting packaging bags were then autoclaved at 121°C for 20 minutes using an LSX-300 autoclave (manufactured by Tommy Industries Co., Ltd.).

[0104] <Cultivation Procedures for Bacillus subtilis and Escherichia coli W3110> As a preculture, the test strain Bacillus subtilis or Escherichia coli W3110 was inoculated into LB media (manufactured by Difco) and cultured in a test tube at 37°C and 200 rpm for 20 hours to obtain a preculture solution. Next, the preculture solution was adjusted to an absorbance of 0.05 at a wavelength of 600 nm using LB media. Using an electric pipettor, 2 mL per section of the adjusted preculture solution was added to the above packaging bag and 20 mL each was added into the baffled flask. After that, the opening of the packaging bag was sealed with a heat-sealing tester. Next, the packaging bag and the flask to which the absorbance-adjusted preculture solution was added were placed in a thermostat at 37°C and cultured for 4 hours for Bacillus subtilis and 8 hours for Escherichia coli W3110, respectively. The packaging bag was left stationary in the thermostat, and the baffled flask was shaken at a shaking speed of 180 rpm using a constant temperature shaking incubator (BR-43FL, manufactured by Taitec Co., Ltd.).

[0105] <Cultivation Procedures for Saccharomyces cerevisiae ATCC201388> As a preculture, the test strain Saccharomyces cerevisiae ATCC201388 was inoculated into YPD medium and cultured in a test tube at 30°C and 200 rpm for 20 hours to obtain a preculture solution. Next, the preculture solution was adjusted to an absorbance of 0.05 at a wavelength of 600 nm using YPD medium. Using an electric pipettor, 2 mL per section of the adjusted preculture solution was added to the above packaging bag and 20 mL each was added into the baffled flask. After that, the opening of the packaging bag was sealed with a heat-sealing tester. Next, the packaging bag and the flask to which the absorbance-adjusted preculture solution was added were placed in a thermostat at 33°C and cultured for 24 hours. The packaging bag was left stationary in the thermostat, and the baffled flask was shaken at a shaking speed of 180 rpm using a constant temperature shaking incubator (BR-43FL, manufactured by Taitec Co., Ltd.).

[0106] [Criteria for evaluating growth rate in static culture using packaging bags] For both statically cultured cultures in packaging bags and shaken cultures in flasks, the absorbance of each culture medium at a wavelength of 600 nm was measured using a UV-Vis spectrophotometer (UV-1800, Shimadzu Corporation). For the statically cultured cultures in packaging bags, the absorbance of each culture medium in four compartments was measured and the average value was taken. The growth rate in static culture was evaluated according to the following criteria by calculating the value obtained by dividing the above average value by the absorbance of the culture medium cultured with shaking in flasks (relative value of the absorbance of the statically cultured culture medium relative to the absorbance of the shaking culture medium; hereinafter simply referred to as "relative value"). The evaluation results are shown in Table 2. ○: Relative value is 0.9 or higher ×: Relative value is less than 0.9 A relative value of 0.9 or higher was considered to indicate that the culture could be performed at a growth rate equivalent to or better than that achieved by shaking culture in a flask.

[0107] [Synthesis Example 1] <Production of 4-methyl-1-pentene·1-hexadecene·1-octadecene copolymer (A-1)> Following the method of Comparative Example 9 in International Publication No. 2006 / 054613, the amount of monomer charged was changed so that the content of constituent units derived from 4-methyl-1-pentene, 1-hexadecene, and 1-octadecene in the resulting copolymer was as shown in Table 1 below. The amount of hydrogen during polymerization was also adjusted to achieve the composition and physical properties shown in Table 1 below, thereby obtaining 4-methyl-1-pentene·1-hexadecene·1-octadecene copolymer (A-1). Subsequently, granulation was performed using a twin-screw extruder (model: BT-30 (screw diameter 30 mmφ, L / D=46)) manufactured by Plastics Engineering Laboratory Co., Ltd., under the conditions of a set temperature of 270°C, a resin extrusion rate of 60 g / min, and a screw rotation speed of 200 rpm to obtain pellets. The results of the measurements of the various physical properties are shown in Table 1.

[0108] [Synthesis Example 2] <Production of 4-methyl-1-pentene·1-decene copolymer (A-2)> Following the method of Comparative Example 7 in International Publication No. 2006 / 054613, the amount of monomer charged was changed so that the content of constituent units derived from 4-methyl-1-pentene and 1-decene in the resulting copolymer was as shown in Table 1 below, and the amount of hydrogen during polymerization was adjusted so that the composition and physical properties were as shown in Table 1 below, thereby obtaining 4-methyl-1-pentene·1-decene copolymer (A-2). Subsequently, pellets were obtained in the same manner as for copolymer (A-1). The results of the measurements of the various physical properties are shown in Table 1.

[0109] [Synthesis Example 3] <Production of 4-methyl-1-pentene-propylene copolymer (B-1)> Following the method of Synthesis Example 4 in International Publication No. 2024 / 111565, 300 mL of n-hexane (dried on activated alumina under a dry nitrogen atmosphere) and 450 mL of 4-methyl-1-pentene were charged at 23°C into a 1.5 L stainless steel polymerizer equipped with stirring blades, which was thoroughly purged with nitrogen. 0.75 mL of a 1.0 mmol / mL toluene solution of triisobutylaluminum (TIBAL) was added to the polymerizer, and the stirrer was turned on. Next, the polymerizer was heated until the internal temperature reached 60°C, and pressurized with propylene to a total pressure (gauge pressure) of 0.19 MPa. Next, 0.34 mL of a toluene solution containing 1 mmol (in Al equivalent) of methylaluminoxane and 0.01 mmol of diphenylmethylene (1-ethyl-3-t-butyl-cyclopentadienyl)(2,7-di-t-butyl-fluorenyl)zirconium dichloride, which had been prepared in advance, was injected into the polymerizer under nitrogen pressure to start the polymerization reaction. During the polymerization reaction, the temperature inside the polymerizer was adjusted to 60°C. 60 minutes after the start of polymerization, 5 mL of methanol was injected into the polymerizer under nitrogen pressure to stop the polymerization reaction, and then the polymerizer was depressurized to atmospheric pressure. After depressurization, acetone was added to the reaction solution while stirring to obtain a polymerization reaction product containing the solvent. The obtained polymerization reaction product containing the solvent was then dried under reduced pressure at 100°C for 12 hours to obtain 4-methyl-1-pentene·propylene copolymer (B-1).

[0110] Next, the above process was scaled up and carried out to obtain a sufficient amount of copolymer (B-1). Using a φ40 mm single-screw extruder manufactured by Modern Machinery Co., Ltd., the copolymer (B-1) was melted and kneaded at a cylinder temperature of 210°C and a screw rotation speed of 50 rpm. The molten strands extruded from a φ4 mm round-hole die were cooled and solidified in a water bath set at 10°C. After that, pellets were obtained by cutting the strands using a strand cutter (model ST-SG3.0) manufactured by Freesia Macross Corporation. The pellets were used as copolymer (B-1) for measuring various physical properties and for forming the film. The measurement results for the various physical properties are shown in Table 1.

[0111] [Table 1]

[0112] [Examples 1-5, Comparative Examples 2-3] Laminates were manufactured using a multilayer sheet molding machine (die width 350 mm) equipped with two 20 mmφ single-screw extruders. Copolymer (A-1) was loaded into one single-screw extruder as the resin material for the base layer, and copolymers (A-1), (A-2), and (B-1) were loaded into the other single-screw extruder as resin materials for the sealant layer in the proportions shown in Table 2. The cylinder temperature and die temperature of both single-screw extruders were set to 280°C. The molten resin material for the base layer and the molten kneaded resin material for the sealant layer were co-extruded from a T-die to the thickness shown in Table 2, and cast molding was performed using a mirror-finish roll set to 80°C to obtain the laminates (laminated films) of Examples 1-5 and Comparative Examples 2-3.

[0113] [Comparative Example 1] A single-layer film was obtained in the same manner as in Examples 1-5 and Comparative Examples 2-3, except that a resin material for the sealant layer was not used.

[0114] [Table 2]

[0115] In Table 2, "-" indicates that there are no measurements available.

[0116] As shown in Table 2, the films of Examples 1 to 5 have higher heat seal strength and can be sterilized by high-pressure steam compared to the films of Comparative Examples 1 to 3. Furthermore, it was found that when microorganisms were cultured statically in packaging bags obtained using the films of Examples 1 to 5, they could be cultured at a rate equivalent to or better than that obtained when cultured with shaking in a flask.

Claims

1. A laminate comprising a base layer and a sealant layer, The sealant layer comprises a resin composition containing a polymer (A) that satisfies the following requirements (A-I) and a polymer (B) that satisfies the following requirements (B-I). The thickness of the sealant layer is 1000 μm or less. A laminate in which the substrate layer contains a polymer (C) that satisfies the following requirements (C-I). (A-I): Polymer (A) contains 50 to 100 mol% of structural units derived from 4-methyl-1-pentene and 0 to 50 mol% of structural units derived from α-olefins having 5 to 20 carbon atoms (excluding 4-methyl-1-pentene). (B-I): Polymer (B) contains 50 to 95 mol% of structural units derived from 4-methyl-1-pentene and 5 to 50 mol% of structural units derived from α-olefins having 2 to 4 carbon atoms. (C-I): Polymer (C) contains 50 to 100 mol% of structural units derived from 4-methyl-1-pentene and 0 to 50 mol% of structural units derived from α-olefins having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene).

2. When the sum of the content of polymer (A) and the content of polymer (B) is 100% by mass, The polymer (A) content is 5 to 85% by mass. The laminate according to claim 1, wherein the polymer (B) content is 95 to 15% by mass.

3. The laminate according to claim 1 or 2, wherein the polymer (A) contains 88 to 100 mol% of structural units derived from 4-methyl-1-pentene and 0 to 12 mol% of structural units derived from α-olefins having 5 to 20 carbon atoms (excluding 4-methyl-1-pentene).

4. The laminate according to claim 1 or 2, wherein the polymer (B) contains 50 to 87 mol% of structural units derived from 4-methyl-1-pentene and 13 to 50 mol% of structural units derived from α-olefins having 2 to 4 carbon atoms.

5. The laminate according to claim 1 or 2, wherein the polymer (A) has a melting point of 150°C or higher.

6. The laminate according to claim 1 or 2, wherein the melting point of the polymer (B) is less than 150°C.

7. The intrinsic viscosity of the polymer (A) in decalin at 135°C is 0.5 to 5.0 dl / g. The laminate according to claim 1 or 2, wherein the intrinsic viscosity of the polymer (B) in decalin at 135°C is 0.5 to 5.0 dl / g.

8. The laminate according to claim 1 or 2, wherein when the melting point of polymer (A) is TmA and the melting point of polymer (B) is TmB, TmA - TmB ≥ 60°C.

9. The laminate according to claim 1 or 2, wherein the content of the polymer (C) in the substrate layer exceeds 50% by mass.

10. A packaging film comprising the laminate according to claim 1 or 2.

11. A packaging bag comprising a heat-sealed portion in which the sealant layers of the packaging film according to claim 10 are fused together by heat sealing.

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