Multilayer film, container and method for manufacturing the same, and method for culturing cells

Abstract

To provide a multilayer film that allows for the heat sealing of containers that have high oxygen permeability and are resistant to tearing from impacts such as dropping when containing liquid. [Solution] The device comprises a heat-seal layer containing polyolefin, a core layer containing styrene-based elastomer, and an outer layer containing 4-methyl-1-pentene copolymer, with an oxygen permeability of 3.0 L / (m³) at 23°C. 2 ·day · atm) or more 100.0L / (m 2 A multilayer film that is less than or equal to (day·atm).

Description

[Technical Field]

[0001] The present invention relates to multilayer films, containers, methods for manufacturing the same, and methods for culturing cells. [Background technology]

[0002] Cell containers are known for propagating, growing, storing, and transporting cells, in which an oxygen-permeable film is heat-sealed to create an airtight container, and a port member attached to a part of the container connects the inside and outside of the container (for example, Patent Document 1). Patent Document 1 states that linear low-density polyethylene (LLDPE) and polypropylene can be suitably used as the oxygen-permeable film. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2022 / 014436 [Overview of the project] [Problems that the invention aims to solve]

[0004] Cell vessels are made of oxygen-permeable materials such as LLDPE as described in Patent Document 1. However, if the oxygen permeability of the cell vessels can be further increased, it is expected that the efficiency of cell culture will also be increased.

[0005] Furthermore, cell containers are used to contain cells along with a liquid such as a culture medium and to culture the cells within the container. According to the inventors' new findings, when cell containers are accidentally dropped during transport or storage, they can rupture due to the impact, causing the culture medium and cells they contain to leak out. In particular, cell containers made from films with high oxygen permeability were prone to rupture due to impacts such as drops when transported or stored at low temperatures.

[0006] The present invention has been made in view of the problems of the above-described prior art, and provides a multilayer film capable of forming, by heat sealing, a container having high oxygen permeability and being difficult to break even by an impact such as dropping when containing a liquid therein at a low temperature, a container formed from the multilayer film, a method for manufacturing the container, and a method for culturing cells using the cell container.

Means for Solving the Problems

[0007] One aspect of the present invention for solving the above problems relates to the multilayer film, container, and method for manufacturing the same, and the method for culturing cells described in the following [1] to

[18] . A heat-sealing layer containing a polyolefin, A core layer containing a styrene-based elastomer, An outer layer containing a 4-methyl-1-pentene copolymer, and 2 The oxygen permeability at 23°C is 3.0 L / (m 2 ·day·atm) or more and 100.0 L / (m ·day·atm) or less, Multilayer film. [2] The polyolefin contains an ethylene (co)polymer or a propylene (co)polymer, The multilayer film according to [1]. [3] The polyolefin contains a polyolefin having a melting point of 90°C or higher and 150°C or lower, The multilayer film according to [1] or [2]. [4] The polyolefin contains a polyolefin having a density of 890 kg / m 3 or more and 930 kg / m 3 or less, The multilayer film according to any one of [1] to [3]. [5] The content of the structural unit derived from styrene in the styrene-based elastomer is 5% by mass or more and 30% by mass or less based on the total mass thereof, [6] The styrene-based elastomer is at least one styrene-based elastomer selected from the group consisting of hydrogenated styrene-butadiene-styrene block copolymer (HSBR), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), and styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS). A multilayer film as described in any of [1] to [5]. [7] The outer layer or the core layer comprises a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, or a copolymer of propylene and an α-olefin (excluding propylene) having 2 to 20 carbon atoms. A multilayer film as described in any of [1] to [6]. [8] The 4-methyl-1-pentene copolymer has a composition in which the amount of constituent units derived from 4-methyl-1-pentene is 80 mol% or more and 99 mol% or less of the total constituent units, and the amount of constituent units derived from α-olefins (excluding 4-methyl-1-pentene) having 4 to 20 carbon atoms is 1 mol% or more and 20 mol% or less of the total constituent units. A multilayer film as described in any of [1] to [7]. [9] The heat seal strength when the heat seal layers are heat-sealed together at 150°C is 10 N / 15 mm or more and 300 N / 15 mm or less. A multilayer film as described in any of [1] to [8].

[10] The thickness is 20 μm or more and 1 mm or less. A multilayer film as described in any of [1] to [9].

[11] The ratio of the thickness of the heat seal layer to the thickness of the core layer is 1:10 or more and 5:1 or less. A multilayer film as described in any of [1] to

[10] .

[12] Used in the formation of cell vessels, A multilayer film as described in any of [1] to

[11] .

[13] One or more multilayer films according to any of [1] to

[12] are heat-sealed together to form a bag, container.

[14] Having a port member that connects the inside and outside of the container, The port member is bonded to the multilayer film in the heat-sealed portion of the heat-seal layer. The container described in

[13] .

[15] A cell container, as described in

[13] or

[14] .

[16] The sterile assurance level (SAL) of the medical device measured in accordance with BS EN556-1:2001 is 10 -3 The following is: The container described in any of

[13] to

[15] .

[17] A method for manufacturing a container, comprising the step of heat-sealing one or more multilayer films described in any of [1] to

[12] to form a bag. A step of introducing cells into a cell container containing a multilayer film as described in any of

[18] [1] to

[12] , The process of culturing cells in the aforementioned cell vessel, A method for culturing cells, comprising the following characteristics. [Effects of the Invention]

[0008] The present invention provides a multilayer film that has high oxygen permeability and is resistant to tearing by impacts such as dropping when it contains liquid at low temperatures, which can be formed by heat sealing; a container formed from the multilayer film; a method for manufacturing the container; and a method for culturing cells using the cell container. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1A is a plan view showing the appearance of a cell vessel manufactured from a multilayer film according to one embodiment of the present invention, and Figure 1B is a partial cross-sectional view of the cell vessel shown in Figure 1A along the dashed line 1B-1B. [Modes for carrying out the invention]

[0010] 1. Multilayer film A first embodiment of the present invention relates to a multilayer film. The multilayer film has a heat-seal layer, a core layer, and an outer layer. The heat-seal layer, the core layer, and the outer layer are laminated in this order.

[0011] 1-1. Heat seal layer A heat-seal layer is a layer that can be fused to another by overlapping different parts of the same heat-seal layer, or by overlapping it with another heat-seal layer, and then heating and pressurizing it.

[0012] Furthermore, according to the inventors' findings, containers molded from multilayer films often have weak impact resistance in the heat-sealed portion of the heat-seal layer (the adhesive portion 116 in Figures 1A and 1B, described later), and are prone to tearing at that heat-sealed portion. Therefore, by making the heat-seal layer more resistant to tearing even when subjected to impact, the impact resistance of the container can be efficiently improved.

[0013] The heat-seal layer contains a polyolefin. The polyolefin can be an ethylene (co)polymer, a propylene (co)polymer, or a 4-methyl-1-pentene (co)polymer. The polyolefin may contain only one of these (co)polymers, or it may contain multiple of these (co)polymers.

[0014] The above polyolefin may be a homopolymer of ethylene, propylene, or 4-methyl-1-pentene, or a copolymer containing these. From the viewpoint of forming a container that is more resistant to tearing even when subjected to impacts such as dropping, it is preferable that the above polyolefin contains an ethylene (co)polymer or a propylene (co)polymer. Furthermore, from the viewpoint of increasing the flexibility of the multilayer film and increasing the heat seal strength of the heat seal layer, it is preferable that the above polyolefin contains an ethylene copolymer, a propylene copolymer, or a 4-methyl-1-pentene copolymer, all of which are copolymers.

[0015] The ethylene copolymer is preferably a copolymer of ethylene and an α-olefin other than ethylene. The α-olefin other than ethylene is preferably an α-olefin having 2 to 20 carbon atoms. From the viewpoint of gas permeability and heat sealability, propylene (C3), butene (C4), hexene (C6), and octene (C8) are preferred as α-olefins having 2 to 20 carbon atoms. The molar ratio of ethylene to the other α-olefin (ethylene / other α-olefin) is preferably 80 / 20 to 98 / 2, more preferably 85 / 15 to 97 / 3, and even more preferably 88 / 12 to 96 / 4.

[0016] The propylene copolymer is preferably a copolymer of propylene and an α-olefin other than propylene, and the molar ratio of propylene to the other α-olefin (propylene / other α-olefin) is preferably 70 / 30 or more and 95 / 5 or less.

[0017] The 4-methyl-1-pentene copolymer is preferably a copolymer of 4-methyl-1-pentene and an α-olefin other than 4-methyl-1-pentene, and preferably a copolymer of 4-methyl-1-pentene and propylene. The molar ratio of 4-methyl-1-pentene to propylene (4-methyl-1-pentene / propylene) is preferably 45 / 55 or more and 95 / 5 or less, more preferably 70 / 30 or more and 93 / 7 or less, and even more preferably 75 / 25 or more and 90 / 10 or less.

[0018] The other α-olefins mentioned above may be linear, branched, or cyclic olefins.

[0019] The other linear α-olefins are more preferably α-olefins having 2 to 10 carbon atoms, and even more preferably α-olefins having 2 to 3 carbon atoms. Examples of the other linear α-olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Of these, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-decene are preferred, and ethylene and propylene are more preferred.

[0020] The other branched olefins are preferably α-olefins having 5 to 20 carbon atoms, and more preferably α-olefins having 5 to 15 carbon atoms. Examples of the other branched α-olefins include 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4,4-dimethyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4-ethyl-1-hexene, and 3-ethyl-1-hexene.

[0021] The other olefins that are cyclic olefins are preferably α-olefins having 5 to 20 carbon atoms, and more preferably α-olefins having 5 to 15 carbon atoms. Examples of the other α-olefins that are cyclic olefins include cyclopentene, cyclohexene, cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, and vinylcyclohexane.

[0022] The 4-methyl-1-pentene polymer, which is a copolymer, may also be a copolymer with monomers other than α-olefins. Examples of monomers other than α-olefins include aromatic vinyl compounds, conjugated dienes, functionalized vinyl compounds, and unconjugated polyenes.

[0023] Examples of the aromatic vinyl compounds mentioned above include styrene, as well as monoalkylstyrenes or polyalkylstyrenes such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene, and p-ethylstyrene.

[0024] The above-mentioned conjugated diene is preferably a compound having 4 to 20 carbon atoms, and more preferably a compound having 4 to 10 carbon atoms. Examples of the above-mentioned conjugated diene include 1,3-butadiene, isoprene, chloroprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 4-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-octadiene.

[0025] Examples of the functionalized vinyl compounds mentioned above include hydroxyl group-containing olefins, halogenated olefins, unsaturated carboxylic acids such as (meth)acrylic acid, propionic acid, 3-butenoic acid, 4-pentenoic acid, 5-hexenoic acid, 6-heptenoic acid, 7-octenoic acid, 8-nonenic acid, 9-decenoic acid, and 10-undecenoic acid, as well as their acid anhydrides or acid halides, unsaturated amines such as allylamine, 5-hexenamine, and 6-heptenamine, (2,7-octadienyl)succinic anhydride, pentapropenylsuccinic anhydride, unsaturated epoxy compounds, and ethylenically unsaturated silane compounds. The hydroxyl group-containing olefins mentioned above can be linear or branched α-olefins having 2 to 20 carbon atoms, preferably linear or branched α-olefins having 2 to 15 carbon atoms, with terminally hydroxyl groups formed. The above-mentioned halogenated olefin can be a halogenated product of a linear or branched α-olefin having 2 to 20 carbon atoms, preferably a linear or branched α-olefin having 2 to 15 carbon atoms.

[0026] Examples of the non-conjugated polyene include linear, branched or cyclic polyenes having 5 to 20 carbon atoms, preferably 5 to 10 carbon atoms, norbornene, and norbornadiene. The non-conjugated polyene is preferably 5-vinylidene-2-norbornene or 5-ethylidene-2-norbornene.

[0027] The above polyolefin can be produced by polymerizing a monomer by a known polymerization method such as a gas phase method, a bulk method, or a slurry method in the presence of a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. The monomer may be derived from biomass or from fossil fuels. Also, both biomass-derived monomers and fossil fuel-derived monomers may be used.

[0028] The above polyolefin preferably has a melting point measured by DSC of 80°C or higher and 150°C or lower, more preferably 85°C or higher and 140°C or lower, and even more preferably 90°C or higher and 120°C or lower. The lower the melting point of the polyolefin, the more difficult it is for the heat seal layer to break even when impacted at a low temperature, and the impact resistance of the container at low temperatures can be effectively enhanced. When the heat seal layer contains a plurality of types of polyolefins, it is preferable that the melting point of at least one of the polyolefins (for example, a polyolefin containing 50% by mass or more based on the total mass of the polyolefins contained in the heat seal layer) is within the above range.

[0029] The above polyolefin has a density measured in accordance with ASTM D1505 of 890 kg / m 3 or more and 930 kg / m 3 or less, preferably 895 kg / m 3 or more and 920 kg / m 3 or less, more preferably 890 kg / m 3 or more and 910 kg / m 3The following is even more preferable: The lower the density of the polyolefin, the less likely the heat seal layer is to tear when subjected to impact at low temperatures, thereby effectively improving the impact resistance of the container at low temperatures. When the heat seal layer contains multiple types of polyolefin, it is preferable that the density of at least one of them (for example, a polyolefin containing 50% by mass or more of the total mass of polyolefins contained in the heat seal layer) is within the above range.

[0030] The heat seal layer may contain resins other than polyolefin. Examples of these other resins include block copolymers of ethylene and silicone. Block copolymers of ethylene and silicone can enhance the antiblocking properties of the heat seal layer.

[0031] The above-mentioned block copolymer of ethylene and silicone can be a (polyethylene)-(silicone) binary block copolymer or a (polyethylene)-(silicone)-(polyethylene) ternary block copolymer, etc. The polyethylene may be a homopolymer of ethylene or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, but it is preferable that it be a homopolymer of ethylene. Furthermore, the molar ratio of ethylene to other α-olefins (ethylene:other α-olefins) when it is a copolymer is preferably 81:19 to 99:1, and more preferably 90:10 to 99:1.

[0032] For example, the block copolymer described above may have the following structure. A-CH2-CH2-Si(CH3)2-O-(Si(CH3)2-O) i -Si(CH3)2-CH2-CH2-A

[0033] Here, the two A's independently represent polyethylene, and i represents an integer of 1 or more. The polyethylene represented by each of the above A's preferably has a number-average molecular weight (Mn) of 100 to 500,000, more preferably 500 to 50,000, and even more preferably 700 to 10,000. i is preferably 1 to 1000, more preferably 1 to 300, and even more preferably 1 to 50.

[0034] The content of the above-mentioned other resins (for example, a block copolymer of ethylene and silicone) is preferably more than 0% by mass and 8% by mass or less, more preferably 0.5% by mass or more and 6% by mass or less, and even more preferably 1% by mass or more and 3% by mass or less, based on the total mass of the heat seal layer.

[0035] 1-2. Core Layer The core layer is a layer containing a styrene-based elastomer. By using a styrene-based elastomer in the core layer, the oxygen permeability of the multilayer film can be increased. Furthermore, compared to 4-methyl-1-pentene copolymers and the like, styrene-based elastomers have higher elongation and strength before peeling or breaking when tensile stress is applied by heat sealing. Therefore, styrene-based elastomers make it less likely for containers formed by heat sealing to break when external forces such as pressure or impact are applied.

[0036] The styrene-based elastomer described above may be any elastomer that contains styrene as a constituent unit. Preferably, the styrene-based elastomer is a hydrogenated product in which some or all of the unsaturated bonds derived from the raw material monomer, such as alkadiene (usually excluding the unsaturated bonds of the benzene ring derived from styrene), are converted to saturated bonds by hydrogenation.

[0037] Examples of the above-mentioned styrene-based elastomers include block copolymers having a polystyrene block and a polyolefin block consisting of structural units derived from an alkadiene having 4 to 10 carbon atoms, and hydrogenated versions thereof. The polyolefin block preferably contains structural units derived from isoprene or butadiene. The block copolymer may be a diblock type copolymer consisting of a polystyrene block and a polyolefin block bonded thereto, or a triblock type copolymer consisting of polystyrene blocks positioned at both ends and a polyolefin block positioned between them.

[0038] Specific examples of the styrene-based elastomers that are block copolymers mentioned above include block copolymers (SBCs) having a polystyrene block as the hard part (crystalline part) and a conjugated diene monomer block such as isoprene or butadiene as the soft part, hydrogenated styrene-butadiene-styrene block copolymer (HSBR), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), and styrene-ethylene-butene-styrene block copolymer (SEBS). Of these, hydrogenated styrene-butadiene-styrene block copolymer (HSBR), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), and styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS) are preferred, with styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS) being more preferred because it has high compatibility with polyolefins and can increase heat seal strength. These styrene-based elastomers may be used individually or in combination of two or more types.

[0039] The styrene-based elastomer can contain styrene-derived structural units in an amount of 5% to 30% by mass relative to its total mass, preferably 5% to 25% by mass, and more preferably 10% to 25% by mass. A lower content of styrene-derived structural units can increase the oxygen permeability of the multilayer film. Furthermore, having a styrene-derived structural unit content within this appropriate range can improve the heat-sealability of the multilayer film.

[0040] The core layer may contain resins other than styrene-based elastomers. Examples of these other resins include ethylene homopolymers such as linear low-density polyethylene (LLDPE), copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, propylene homopolymers, copolymers of propylene and α-olefins (excluding propylene) having 2 to 20 carbon atoms, and butene (co)polymers. Of these, copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, and copolymers of ethylene and α-olefins (excluding propylene) having 2 to 20 carbon atoms are preferred.

[0041] These resins can be used depending on the properties required for the multilayer film. For example, to enable the formation of containers that are more resistant to tearing even when subjected to impacts such as drops, and to improve tensile properties, the core layer may contain a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, or a copolymer of propylene and an α-olefin (excluding propylene) having 2 to 20 carbon atoms. Of these, from the viewpoint of increasing film impact strength and reducing haze, it is preferable that the core layer contains a copolymer of propylene and an α-olefin (excluding propylene) having 2 to 20 carbon atoms. The above-mentioned ethylene (co)polymer, propylene (co)polymer, and butene (co)polymer may be resins consisting of the same structural units as the polyolefin (or some of the resins) contained in the heat seal layer, or they may be resins containing different structural units.

[0042] These ethylene(co)polymers, propylene(co)polymers, and butene(co)polymers can be produced by polymerizing monomers using known polymerization methods such as gas-phase, bulk, or slurry methods in the presence of known catalysts such as Ziegler-Natta catalysts or metallocene catalysts. The monomers may be derived from biomass or fossil fuels. Alternatively, both biomass-derived and fossil fuel-derived monomers may be used.

[0043] The core layer preferably contains, in an amount of 3% to 60% by mass of ethylene and an α-olefin having 3 to 20 carbon atoms, or a copolymer of propylene and an α-olefin (excluding propylene) having 2 to 20 carbon atoms, based on its total mass. The higher the copolymer content, the more resistant the container is to tearing even when subjected to impacts such as dropping. Furthermore, the higher the copolymer content, the higher the tensile properties of the multilayer film can be. The lower the copolymer content, the higher the oxygen permeability of the multilayer film can be. The copolymer content is more preferably 10% to 60% by mass, and even more preferably 20% to 50% by mass. The styrene-based elastomer content relative to the total mass of the core layer is preferably 40% to 97% by mass, more preferably 40% to 90% by mass, and even more preferably 50% to 80% by mass.

[0044] The melt flow rate of the core layer, measured in accordance with ASTM D1238 (2013) at 230°C and a 2.16 kg load, is preferably 0.5 g / 10 min to 15 g / 10 min, and more preferably 1 g / 10 min to 12 g / 10 min.

[0045] The density of the core layer, measured in accordance with JIS K 7112-2:2023, is 0.89 g / cm³. 3 More than 0.91g / cm 3 Preferably, it is 0.89 g / cm³. 3 More than 0.90g / cm 3The following is more preferable: A lower core layer density can improve the oxygen permeability of the multilayer film. Conversely, a higher core layer density can improve the antiblocking properties of the multilayer film.

[0046] 1-3.Outer layer The outer layer is a layer containing a 4-methyl-1-pentene copolymer. The outer layer can serve as a support layer to sandwich and hold the core layer from both the inside and outside, together with the heat seal layer.

[0047] Furthermore, while many materials with high oxygen permeability are soft elastomers, their strong self-adhesion can cause films to block each other when layered, making them difficult to handle. For example, although styrene elastomers have high oxygen permeability, films molded from styrene elastomers are prone to blocking and have poor handling properties. In contrast, the anti-blocking properties of multilayer films can be improved by providing an outer layer and a heat-seal layer.

[0048] The 4-methyl-1-pentene copolymer is preferably a copolymer of 4-methyl-1-pentene and an α-olefin other than 4-methyl-1-pentene. The other α-olefin may be linear, branched, or cyclic.

[0049] The other linear α-olefins are preferably α-olefins having 2 to 20 carbon atoms, and more preferably α-olefins having 4 to 20 carbon atoms. Examples of the other linear α-olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

[0050] The other branched olefins are preferably α-olefins having 5 to 20 carbon atoms, and more preferably α-olefins having 5 to 15 carbon atoms. Examples of the other branched α-olefins include 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4,4-dimethyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4-ethyl-1-hexene, and 3-ethyl-1-hexene.

[0051] The other olefins that are cyclic olefins are preferably α-olefins having 5 to 20 carbon atoms, and more preferably α-olefins having 5 to 15 carbon atoms. Examples of the other α-olefins that are cyclic olefins include cyclopentene, cyclohexene, cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, and vinylcyclohexane.

[0052] The 4-methyl-1-pentene polymer, which is a copolymer, may also be a copolymer with monomers other than α-olefins. Examples of monomers other than α-olefins include aromatic vinyl compounds, conjugated dienes, functionalized vinyl compounds, and unconjugated polyenes.

[0053] Examples of the aromatic vinyl compounds mentioned above include styrene, as well as monoalkylstyrenes or polyalkylstyrenes such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylstyrene, m-ethylstyrene, and p-ethylstyrene.

[0054] The above-mentioned conjugated diene is preferably a compound having 4 to 20 carbon atoms, and more preferably a compound having 4 to 10 carbon atoms. Examples of the above-mentioned conjugated diene include 1,3-butadiene, isoprene, chloroprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 4-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-octadiene.

[0055] Examples of the functionalized vinyl compounds mentioned above include hydroxyl group-containing olefins, halogenated olefins, unsaturated carboxylic acids such as (meth)acrylic acid, propionic acid, 3-butenoic acid, 4-pentenoic acid, 5-hexenoic acid, 6-heptenoic acid, 7-octenoic acid, 8-nonenic acid, 9-decenoic acid, and 10-undecenoic acid, as well as their acid anhydrides or acid halides, unsaturated amines such as allylamine, 5-hexenamine, and 6-heptenamine, (2,7-octadienyl)succinic anhydride, pentapropenylsuccinic anhydride, unsaturated epoxy compounds, and ethylenically unsaturated silane compounds. The hydroxyl group-containing olefins mentioned above can be linear or branched α-olefins having 2 to 20 carbon atoms, preferably linear or branched α-olefins having 2 to 15 carbon atoms, with terminally hydroxyl groups formed. The above-mentioned halogenated olefin can be a halogenated product of a linear or branched α-olefin having 2 to 20 carbon atoms, preferably a linear or branched α-olefin having 2 to 15 carbon atoms.

[0056] Examples of the non-conjugated polyenes mentioned above include linear, branched, or cyclic polyenes, norbornene, and norbornanediene, which have 5 to 20 carbon atoms, preferably 5 to 10 carbon atoms. The non-conjugated polyene is preferably 5-vinylidene-2-norbornene or 5-ethylidene-2-norbornene.

[0057] The 4-methyl-1-pentene copolymer is preferably a copolymer of 4-methyl-1-pentene and an α-olefin (excluding 4-methyl-1-pentene) having 3 to 20 carbon atoms, and more preferably a copolymer of 4-methyl-1-pentene and a linear α-olefin having 3 to 20 carbon atoms. Examples of linear α-olefins having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Of these, a copolymer of 4-methyl-1-pentene and 1-hexadecene or 1-octadecene is preferred.

[0058] From the viewpoint of improving the oxygen permeability of multilayer films, it is preferable that the 4-methyl-1-pentene copolymer has a high proportion of structural units derived from 4-methyl-1-pentene. For example, it is preferable that the proportion of structural units derived from 4-methyl-1-pentene in the 4-methyl-1-pentene copolymer is 80 mol% to 99 mol% of the total structural units. Furthermore, it is preferable that the proportion of structural units derived from α-olefins other than 4-methyl-1-pentene (for example, α-olefins with 4 to 20 carbon atoms (excluding 4-methyl-1-pentene)) in the 4-methyl-1-pentene copolymer is 1 mol% to 20 mol% of the total structural units.

[0059] The outer layer may contain other resins different from the 4-methyl-1-pentene copolymer. Examples of these other resins include ethylene homopolymers such as linear low-density polyethylene (LLDPE), copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, propylene homopolymers, copolymers of propylene and α-olefins (excluding propylene) having 2 to 20 carbon atoms, and butene (co)polymers. Of these, copolymers of ethylene and α-olefins having 3 to 20 carbon atoms, and copolymers of ethylene and α-olefins (excluding propylene) having 2 to 20 carbon atoms are preferred. The ethylene (co)polymer, propylene (co)polymer, and butene (co)polymer may be resins consisting of the same structural units as the polyolefins (some of the resins) contained in the heat seal layer, or they may be resins containing different structural units.

[0060] These ethylene(co)polymers, propylene(co)polymers, and butene(co)polymers can be produced by polymerizing monomers using known polymerization methods such as gas-phase, bulk, or slurry methods in the presence of known catalysts such as Ziegler-Natta catalysts or metallocene catalysts. The monomers may be derived from biomass or fossil fuels. Alternatively, both biomass-derived and fossil fuel-derived monomers may be used.

[0061] The outer layer preferably contains the above-mentioned other resins in an amount of 3% to 40% by mass relative to its total mass. The higher the content of the above-mentioned other resins, the more resistant the container is to tearing even when subjected to impacts such as dropping. Furthermore, the higher the content of the above-mentioned other resins, the higher the tensile properties of the multilayer film can be. The lower the content of the above-mentioned other resins, the higher the oxygen permeability of the multilayer film can be. The content of the above-mentioned other resins is more preferably 5% to 30% by mass, and even more preferably 7% to 25% by mass. The content of 4-methyl-1-pentene copolymer relative to the total mass of the core layer is preferably 60% to 97% by mass, more preferably 70% to 95% by mass, and even more preferably 75% to 93% by mass.

[0062] 1-4. Characteristics of multilayer films The multilayer film according to this embodiment has an oxygen permeability of 3.0 L / (m²) at 23°C. 2 ·day · atm) or more 100.0L / (m 2 (·day·atm) or less, 4.0L / (m 2 ·day · atm) or more 50.0L / (m 2 It is preferable that it be less than or equal to 5.0 L / (m³) 2 ·day · atm) or more 30.0L / (m 2 It is more preferable that the temperature is below (day·atm). Increasing the oxygen permeability of the multilayer film can improve the efficiency of cell culture using cell containers.

[0063] Furthermore, the multilayer film has a carbon dioxide transmission rate of 10 L / (m²) at 23°C. 2 ·day · atm) or more 400L / (m 2 It is preferable that it is less than or equal to 10 L / (m³) 2 ·day · atm) or more 300L / (m 2 It is more preferable that the carbon dioxide permeability is below (day·atm). The higher the carbon dioxide permeability, the more efficient the cell culture using the cell vessel can be.

[0064] Oxygen and carbon dioxide permeability were measured in accordance with JIS K 7126-1:2006 using a differential pressure gas permeability measuring device (manufactured by Toyo Seiki Seisakusho) at a test temperature of 23°C and a test relative humidity of 0%RH, with a measurement area of ​​5 cm² of multilayer film. 2 The measurement is performed as follows: When high oxygen or carbon dioxide permeability is expected, an aluminum mask is applied to the sample beforehand, and the actual permeable area is 5.0 cm². 2 It is preferable to do so.

[0065] The multilayer film has a film impact strength measured from the opposite side of the heat-seal layer in accordance with ASTM-D 3420:2021, which is between 7 kJ / m and 40 kJ / m, preferably 8 kJ / m or higher, and more preferably 9 kJ / m or higher. The higher the film impact strength, the more resistant the container is to tearing even when subjected to impacts such as dropping. There is no particular upper limit to the film impact strength, but it can be, for example, 40 kJ / m or lower.

[0066] The multilayer film preferably has a Young's modulus of 50 MPa to 400 MPa at 23°C, measured in accordance with JIS K7127:1999, more preferably 120 MPa to 350 MPa, even more preferably 150 MPa to 300 MPa, and particularly preferably 150 MPa to 250 MPa. The lower the Young's modulus, the easier the multilayer film is to stretch and absorb energy from impact. There is no particular lower limit to the Young's modulus, but from the viewpoint of improving the transportability of the film, it is preferable to set it to 50 MPa or higher.

[0067] The multilayer film preferably has a tensile elongation at 23°C measured in accordance with JIS K7127:1999 of 300% to 1000%, more preferably 320% to 1000%, and even more preferably 330% to 1000%. The greater the tensile elongation at 23°C, the easier the multilayer film is to stretch and absorb energy from impact. There is no particular upper limit to the tensile elongation at 23°C, but from the viewpoint of improving the cuttability of the film, it is preferable to keep it at 1000% or less.

[0068] The Young's modulus and tensile elongation at break are calculated as the arithmetic mean of values ​​obtained by measuring the multilayer film in the MD direction and TD direction (specifically, the long side direction and the short side direction).

[0069] It is preferable that the multilayer film has high welding strength when heat-sealed. Specifically, it is preferable that the welding strength when the multilayer film is heat-sealed at 150°C is 5N / 15mm width or more and 300N / 15mm width or less, more preferably 10N / 15mm width or more and 200N / 15mm width or less, and even more preferably 15N / 15mm width or more and 200N / 15mm width or less.

[0070] When measuring the heat-sealing strength of a multilayer film, two rectangular heat-sealing test pieces measuring 150 mm wide x 50 mm high are cut from the resin film so that the vertical direction coincides with the MD (Machine Direction) direction of the resin film. Next, these two heat-sealing test pieces are placed on top of each other so that the heat-sealing layers of the two multilayer films face each other. Then, using a heat-sealing test machine (Tester Industries Co., Ltd., thermal gradient heat-sealing tester, model TP-701-G), the upper and lower temperatures (heat-sealing temperature) of the heat-sealing bar are set to 150°C, the seal width is 5 mm, the seal pressure is 0.2 MPa, and the seal time is 2 seconds, and the two heat-sealed multilayer films are removed from the test machine, and strip-shaped test pieces with a width of 15 mm are cut out in directions perpendicular and parallel to the heat-sealing line as surface-to-surface heat-sealing test pieces of the multilayer film. Using a tensile testing machine (Orientec Co., Ltd., Tensilon Universal Material Testing Machine, Model RTG-1250), strip-shaped test pieces were peeled at a test temperature of 23°C, with a chuck distance of 50 mm and a tensile speed of 300 mm / min. The maximum peel strength was measured and defined as the heat seal strength (unit: N / 15 mm). The heat seal strength was measured for five test pieces, and the average value was calculated.

[0071] Furthermore, the multilayer film has a moisture permeability of 10 g / m² at 40°C and 90% relative humidity. 2 ·day) or more 100g / (m 2 It is preferable that it is less than or equal to 12 g / (m 2 ·day) or more than 80g / (m 2 It is more preferable that it be less than or equal to 14g / (m 2 ·day) or more 60g / (m 2 It is even more preferable that the moisture permeability is less than or equal to (day). By keeping the moisture permeability within this range, moisture loss from the contents is minimized.

[0072] The moisture permeability is calculated according to the isobaric method (cup type - gravimetric method) described in JIS Z 0208:2021, under condition B (test temperature 40°C, test relative humidity 90%RH).

[0073] From the viewpoint of improving the efficiency of cell observation, the multilayer film is preferably highly transparent to visible light and has low haze. Specifically, the total light transmittance measured in accordance with ASTM D-1003:2021 is preferably 50% to 100%, more preferably 70% to 100%, and even more preferably 90% to 100%. In addition, the haze measured in accordance with ASTM D-1003:2021 is preferably 0% to 20%, and more preferably 0% to 10%.

[0074] The multilayer film is preferably 20 μm to 1 mm thick, more preferably 30 μm to 500 μm thick, and even more preferably 40 μm to 300 μm thick. The thicker the multilayer film, the greater the strength of the container and the welding strength when heat-sealed. The thinner the multilayer film, the greater the permeability of oxygen and carbon dioxide gases.

[0075] The thickness of the heat seal layer is preferably 5 μm to 300 μm, more preferably 5 μm to 200 μm, and even more preferably 5 μm to 150 μm. The thicker the heat seal layer, the better the heat sealability of the multilayer film. The thinner the heat seal layer, the better the oxygen permeability of the multilayer film.

[0076] The ratio of the thickness of the heat-seal layer to the total thickness of the multilayer film (heat-seal layer / multilayer film) is preferably 1 / 100 or more and 50 / 100 or less, more preferably 2 / 100 or more and 40 / 100 or less, and even more preferably 5 / 100 or more and 35 / 100 or less.

[0077] The thickness of the core layer is preferably 10 μm to 500 μm, more preferably 15 μm to 300 μm, and even more preferably 20 μm to 100 μm. The thicker the core layer, the higher the impact resistance of the multilayer film. By making the core layer appropriately thinner, the heat seal strength of the multilayer film can be increased.

[0078] The ratio of the thickness of the core layer to the total thickness of the multilayer film (core layer / multilayer film) is preferably 10 / 100 or more and 80 / 100 or less, more preferably 20 / 100 or more and 70 / 100 or less, and even more preferably 30 / 100 or more and 65 / 100 or less.

[0079] The thickness of the outer layer is preferably 5 μm to 300 μm, more preferably 10 μm to 200 μm, and even more preferably 20 μm to 150 μm. A thicker outer layer increases the heat seal strength of the multilayer film. Conversely, a thinner outer layer increases the oxygen permeability of the multilayer film.

[0080] The ratio of the thickness of the heat seal layer to the thickness of the core layer (heat seal layer / core layer) is preferably 1 / 10 or more and 5 / 1 or less, more preferably 1 / 8 or more and 3 / 1 or less, and even more preferably 1 / 6 or more and 2 / 1 or less. Increasing the ratio of the heat seal layer thickness can improve the heat seal strength and tensile properties. Increasing the ratio of the core layer thickness can improve gas permeability.

[0081] Furthermore, it is preferable that the multilayer film has an indicator portion indicating that the surface is a heat-seal layer, or an indicator portion indicating that the surface is an outer layer that is on the outside of the cell container. The indicator portion may be formed by attaching a sticker to one or both surfaces of the multilayer film indicating which surface it is. Alternatively, the indicator portion may be formed by writing on the outer layer with ink or the like to indicate which surface it is.

[0082] 1-5. Method for manufacturing multilayer films The multilayer film described above can be manufactured by a process of preparing the materials for each layer and a process of melting the prepared materials and co-extruding them to obtain the multilayer film.

[0083] In the preparation process, a heat-seal layer material containing polyolefin, a core layer material containing styrene-based elastomer, and an outer layer material containing 4-methyl-1-pentene copolymer are prepared. The materials for each of these layers can be any of the materials described above, and it is preferable to select them so that they satisfy the above-described properties after molding.

[0084] In the process of obtaining a multilayer film, the materials for each layer are melted and kneaded, and then co-extruded using a T-die extrusion machine or an extrusion lamination machine. The co-extruded material may be molded by an inflation method or a casting method.

[0085] 2. Container Multilayer films can be used to create cell containers by stacking two or more multilayer films, or by folding a single multilayer film, overlapping the edges, and then heat-sealing the edges to form a bag. When stacking the films, the heat-sealed layers should be positioned facing each other.

[0086] Figure 1A is a plan view showing the appearance of a cell vessel manufactured from the multilayer film described above, and Figure 1B is a partial cross-sectional view of the cell vessel shown in Figure 1A along the dashed line 1B-1B.

[0087] The cell container 100 includes containers that are shaped like bags and are used to culture cells by introducing a culture medium and cells into them. In this specification, cell culture means increasing, growing, or maintaining the cells in a living state.

[0088] The cell container 100 is formed by overlapping two multilayer films 112 and 114, and creating a sealed portion 116 around the entire circumference of the edges to form a substantially sealed bag portion 110. In a portion of the heat-sealed sealed portion 116, one or more port members 200 (three in this embodiment) are sandwiched between the multilayer films 112 and 114. The port members 200 are cylindrical members that connect the inside and outside of the bag portion 110, and are welded in contact with the heat-seal layer to adhere to these multilayer films. Alternatively, the port members 200 may be welded between the heat-seal layer of the multilayer films 112 and 114 via another welding sheet.

[0089] The heat sealing can be performed, for example, at a temperature of 120°C to 200°C, preferably 140°C to 180°C, and at a pressure of 0.1 MPa to 0.5 MPa, preferably 0.1 MPa to 0.2 MPa, for 1 second to 10 seconds, preferably 1 second to 5 seconds.

[0090] The heat sealing described above joins the heat-sealed layers of the stacked multilayer films together.

[0091] Furthermore, when stacking and arranging multilayer films, the multilayer films may be shaped into a predetermined form by methods such as vacuum forming, pressure forming, and vacuum pressure forming. In this case as well, it is sufficient that the edges of the multilayer films are stacked and arranged. As for the joining method of multilayer films, in addition to the method of heat sealing by sandwiching the stacked multilayer films between two hot plates, high-frequency welding and laser welding can also be applied. For example, in the case of laser welding, as described in the method of Japanese Patent No. 4279674, a method can be used in which laser light in the wavelength range of 1.8 to 2 μm emitted from a Ho-YAG laser or Tm fiber laser, or laser light with a wavelength of 10.6 μm emitted from a carbon dioxide laser is irradiated onto the parts to be joined of the stacked multilayer films, causing the multilayer films to directly absorb the energy of the laser light and melt the parts to be joined, thereby welding them together.

[0092] Furthermore, the number of multilayer films used to prepare the cell container 100 is not limited to two. One multilayer film may be folded, its edges overlapping, and the edges heat-sealed to form a bag, or three or more multilayer films may be used to form the cell container.

[0093] Furthermore, cell containers can be sterilized after preparation and before use. Gamma ray sterilization is preferred as the sterilization method, given the gamma ray irradiation resistance of the film material. The gamma ray irradiation dose is preferably in the range of 10 to 50 kGy. Additionally, cell containers are preferably used as single-use items from the viewpoint of preventing contamination and maintaining sterility.

[0094] The container has a sterility assurance level (SAL) of 10, measured in accordance with BS EN556-1:2001. -3 Preferably, 10 -6 The following is more preferable. Here, SAL represents the degree of sterility of the sterilized items after the sterilization process, and is expressed as the probability of microorganisms being present per unit number of sterilized items after sterilization. SAL is 10 -n This is expressed as, and the number of viable bacteria per sterilized item is 10 -n This means that n is 3 or greater, and more preferably 6 or greater.

[0095] 3. Methods for culturing cells The cell containers described above can be used for culturing various types of cells.

[0096] Specifically, an injection port for injecting drugs or other substances, and a tube for connecting to a Luer port are attached to each port component 200. Then, a culture medium containing cells (cell suspension) is introduced into the cell container 100 through the Luer port connected to the tube. Alternatively, a culture medium without cells may be introduced into the cell container 100 first, and then the cell suspension may be introduced afterward.

[0097] Subsequently, the cell container 100 is placed in the incubator and the cells are cultured. The conditions for culturing the cells are not particularly limited and should be selected according to the type of cells being cultured.

[0098] During culture, drugs may be injected through the injection port, or a portion of the cells may be taken to check the culture status. Additionally, some or all of the cells may be transferred to another cell container 100 via a tube attached to the port component.

[0099] Finally, the cultured cells are collected through the tube attached to the port component.

[0100] The cells targeted by the cell container 100 are not particularly limited and may be differentiated somatic cells or undifferentiated stem cells. The cells may be living cells or dead cells.

[0101] 4. Other Embodiments It should be noted that each of the embodiments described above is merely an example of the present invention, and the present invention is not limited to the embodiments described above. It goes without saying that many other diverse embodiments are possible within the scope of the concept of the present invention.

[0102] For example, the multilayer film mentioned above can be used not only for cell containers but also for cell cryopreservation containers, and so on. [Examples]

[0103] The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[0104] [Experiment 1: Film preparation and evaluation] 1. Fabrication of multilayer and single-layer films 1-1.Materials The following materials were prepared. • 4-methyl-1-pentene copolymer 1 (4MP1-1) A 4-methyl-1-pentene copolymer (melting point: 224°C) was defined as 4MP1-1, in which 97.6 mol% of the constituent units were derived from 4-methyl-1-pentene, 1.44 mol% were derived from 1-hexadecene, and 0.96 mol% were derived from 1-octadecene. • 4-methyl-1-pentene copolymer 2 (4MP1-2) A 4-methyl-1-pentene copolymer (melting point: 233°C) in which 98.4 mol% of the constituent units are derived from 4-methyl-1-pentene and 1.6 mol% of the constituent units are derived from 1-octene was designated as 4MP1-2. • 4-methyl-1-pentene copolymer 3 (4MP1-3) A 4-methyl-1-pentene copolymer (melting point: 130°C) having 85 mol% of constituent units derived from 4-methyl-1-pentene and 15 mol% of constituent units derived from propylene was designated as 4MP1-3. SEBS Kraton Polymer Japan Co., Ltd. Kraton G1657VS (Styrene content: 13% by mass, MFR (ASTM D1238 compliant, temperature 230℃, load 2.16kg): 9.0g / 10min, density 900kg / m³) 3 ) was designated as SEBS. • Linear low-density polyethylene (LLDPE-1) Evolu SP2040, manufactured by Prime Polymer Co., Ltd. (Melting point: 116℃, Density: 918kg / m³) 3 ) was designated as LLDPE-1. • Linear low-density polyethylene (LLDPE-2) Evolu SP1071C, manufactured by Prime Polymer Co., Ltd. (Melting point: 100℃, Density: 910kg / m³) 3 ) was designated as LLDPE-2. • Linear low-density polyethylene (LLDPE-3) Evolu SP0540, manufactured by Prime Polymer Co., Ltd., melting point: 98℃, density: 905kg / m³ 3 ) was designated as LLDPE-3. • Copolymer of propylene and α-olefin (PP) A propylene-based resin composition (MFR (ASTM D1238), temperature 230°C, load 2.16kg) 6.0g / 10min, density 868kg / m³) is obtained by melt-kneading 90% by mass of a propylene-ethylene-1-butene copolymer (Copolymer C), which is prepared according to the method described in the Examples section of the Third Invention in International Publication No. 2006 / 57361, has an ethylene content of 16 mol%, a propylene content of 78 mol%, a 1-butene content of 6 mol%, and an MFR (according to ASTM D1238, temperature 230°C, load 2.16kg) of 6g / 10min, and 10% by mass of a propylene homopolymer (MFR (ASTM D1238, temperature 230°C, load 2.16kg) 7.0g / 10min, melting point 160°C). 3 ) was used as a propylene copolymer (PP). • Copolymer of 1-butene and α-olefin (PB) Toughmer BL3450M, manufactured by Mitsui Chemicals, Inc. (Melting point: 100°C, MFR (ASTM D1238 compliant, temperature 190°C, load 2.16kg): 4.0g / 10min, density 910kg / m³) 3 ) was designated as PB. • Block copolymer of ethylene and silicone Polyethylene having a vinyl group at one end, synthesized according to the method described in Synthesis Example 2 of International Publication No. 2012 / 098865, was used as an ethylene / silicone block copolymer.

[0105] 1-2. Fabrication of multilayer and single-layer films Using a tumbler blender, each material was mixed (dry blended) in the proportions listed in Tables 1 to 4 to prepare resin compositions for each layer.

[0106] Each layer's resin composition was supplied to its respective extruder, and using a cast molding die (die width 350 mmφ, lip gap 1 mm), the extrusion rate of each extruder was set so that the resin temperature reached 270°C and the thickness ratios of the outer layer, core layer, and heat seal layer were 1:1:1, 1:3:1, 2:2:1, 1:5:1, or 4:5:1 in that order. Multilayer films 1 to 38 with a thickness of 100 μm were obtained by co-extrusion molding (except for multilayer film 36, which had a thickness of 50 μm). The molding speed was 4 m / min.

[0107] LLDPE-1 was supplied to an extruder, and a single-layer film 39 with a thickness of 100 μm was obtained by single-layer extrusion molding using a cast molding die (die width 350 mmφ, lip gap 1 mm) at a resin temperature of 230°C. The molding speed was 4 m / min.

[0108] Tables 1 to 4 show the total thickness, thickness ratio, and materials and their quantities used in each layer of the fabricated multilayer films 1 to 38 and single-layer film 39. In Tables 1 to 4, the "thickness ratio" column indicates the ratio of the thickness of the outer layer / core layer / heat seal layer, and the "materials for each layer" column indicates the quantity (in parts by mass) of each material used in the fabrication of each layer.

[0109] [Table 1]

[0110] [Table 2]

[0111] [Table 3]

[0112] [Table 4]

[0113] 2. Measurement of multilayer and single-layer films 2-1. Oxygen permeability Oxygen permeability was measured in accordance with JIS K 7126-1:2006 using a differential pressure gas permeability measuring device (manufactured by Toyo Seiki Seisakusho) under test conditions of a test temperature of 23°C and test humidity of 0%RH, with a measurement area of ​​5 cm² of film. 2 The measurement was performed as follows: The measurement area of ​​the film was adjusted by preparing two adhesive aluminum masks manufactured by Modern Control, each with a 25mm diameter hole in the center, and stacking the film to be measured between these two masks. Specifically, the film was positioned so that the central holes of the two masks overlapped.

[0114] 2-2. Film Impact Strength Using a film impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd. (compliant with ASTM-D 3420:2021), the impact strength of each film was measured from the outer layer side, with a film size of 100mm x 100mm, an impact head spherical shape of 0.5 inches in diameter, and a measurement temperature of 23°C.

[0115] 2-3. Tensile Test Each multilayer and single-layer film was cut into strips measuring 15 mm wide x 100 mm long. In accordance with JIS K7127:1999, a tensile testing machine (Instron, universal tensile testing machine 3380) was used to measure Young's modulus (YM) (in MPa) and tensile elongation at break (EL) (in %) in the MD and TD directions of the test specimens under the following conditions: chuck distance of 50 mm, tensile speed of 300 mm / min, and temperature of 23°C. Measurements were performed for both the MD and TD directions, and the average value of these measurements was used as the measurement value for the film in question.

[0116] 2-4. Heat seal strength Two strips measuring 150 mm wide x 50 mm long were prepared from each of the multilayer and single-layer films to serve as test specimens. Next, the two prepared test specimens were stacked so that the heat-seal layers faced each other, and then heat-sealed using a heat-seal tester (Tester Industries Co., Ltd., Thermal Gradient Heat Seal Tester TP-701-G) under the following conditions: upper temperature 150°C, lower temperature 150°C, seal width 5 mm, seal pressure 0.2 MPa, and seal time 2 seconds.

[0117] Next, the heat-sealed test specimens were removed from the heat-seal testing machine and cut into 15mm wide strips. These 15mm wide heat-sealed test specimens were then subjected to a test at a speed of 300mm / min and an ambient temperature of 23°C. The specimens were pulled at a 180° angle to the heat-sealed surface between them to separate them, and the maximum peel strength was measured. This maximum value was defined as the heat-seal strength (unit: N / 15mm). If the specimens stretched to their limit without separation, the maximum observed tensile strength was defined as the heat-seal strength. The heat-seal strength was measured for five specimens, and the average value was calculated.

[0118] 2-5. Moisture permeability The moisture permeability was calculated under condition B (test temperature 40°C, test humidity 90%RH) in accordance with the isobaric method (cup type - gravimetric method) described in JIS Z 0208:2021.

[0119] 2-6. Haze and Total Light Transmittance Each multilayer and single-layer film was cut into 50mm squares to form test specimens. The haze value (in %) and total transmitted light in air were measured using a fully automatic haze meter (Tokyo Denshoku Co., Ltd., TC-HIII DPK, light source: 12V 50W halogen lamp C) in accordance with ASTM D 1003:2021. This measurement was performed at three arbitrary points on each test specimen, and the average of the data from these three points was taken as the measured value. The total light transmittance was then calculated using the following formula. Total light transmittance (%) = 100 × (total transmitted light amount) / (incident light amount)

[0120] The measurement results for multilayer films 1-38 and single-layer film 39 are shown in Tables 5-8.

[0121] [Table 5]

[0122] [Table 6]

[0123] [Table 7]

[0124] [Table 8]

[0125] 3. Preparation and evaluation of cell culture bags 3-1. Drop test of cell culture bags Two films measuring 210 mm in length and 148 mm in width were prepared by cutting each multilayer film and single-layer film. The films were arranged so that the heat-seal layers faced each other, and the three sides were heat-sealed with a width of 10 mm at a sealing temperature of 150°C, a sealing pressure of 0.2 MPa, and a sealing time of 1 second to obtain a bag component.

[0126] High-density polyethylene (melting point 133°C, density 953 kg / m³) is produced by injection molding. 3Port members were fabricated using either MFR 190℃·2.16kgf=5.8g / 10min or 4MP1-1. The fabricated port members had circular cross-sections for both the narrow and wide sections, with an outer diameter of 8mm and an inner diameter of 4mm for the narrow section, an outer diameter of 10mm for the wide section, and an inner diameter of 6mm for the wide section. Bags were fabricated using port members made of 4MP1-1 for multilayer films 37 and 38, and port members made of high-density polyethylene for the other multilayer films and single-layer film 39.

[0127] A cell culture bag with a port component was obtained by heat sealing it with a welding line width (joint width) of 10 mm under the conditions of a sealing temperature of 200°C, a sealing pressure of 0.2 MPa, and a sealing time of 4 seconds.

[0128] The resulting cell culture bags with port components were filled with 300 ml of water, and the port components were sealed with a silicone resin stopper with an upper diameter of 13 mm, a lower diameter of 10 mm, and a height of 18 mm. After standing for one day in an atmosphere of 23°C and 4°C, the water-filled bags were dropped horizontally from a height of 50 cm (so that the flat side of the bag hit the surface of impact) in accordance with JIS Z 0238:1998. If the bags did not rupture, they were then dropped vertically from a height of 50 cm (so that the heat-sealed part opposite the port component hit the surface of impact). The size of the rupture in the bags after dropping was measured, and they were classified according to the following classification criteria. ○: Does not tear the bag Small: Damage area less than 3cm in size Medium: Damage area is 3cm or larger but less than 5cm in size. Large: Damage area is 5cm or larger.

[0129] For each film, the evaluation results of the cell culture bags prepared from that film are shown in Tables 9 to 12.

[0130] [Table 9]

[0131] [Table 10]

[0132] [Table 11]

[0133] [Table 12]

[0134] The results shown in Tables 1 to 12 indicate that the material comprises a heat-seal layer containing polyolefin, a core layer containing styrene-based elastomer, and an outer layer containing 4-methyl-1-pentene copolymer, with an oxygen permeability of 3.0 L / (m³) at 23°C. 2 ·day · atm) or more 100.0L / (m 2 It can be seen that multilayer films with a temperature of less than or equal to (day·atm) can be molded into containers that are resistant to tearing even when dropped or subjected to other impacts when they contain liquid at low temperatures.

[0135] [Experiment 2: Cell Culture Test] Two films measuring 120 mm in length and 120 mm in width were prepared by cutting from multilayer film 36 and single-layer film 39. A bag component was fabricated by heat sealing in the same manner as in "3-1. Drop test of cell culture bag," and a cell culture bag with a port component made of high-density polyethylene was obtained. The culture area (area of ​​the culture site on the surface parallel to the film) was 100 cm² in all cases. 2 That was the case.

[0136] The cell culture bags were sterilized by irradiating them with gamma rays at a dose of 25 kGy. The Sterility Assurance Level (SAL) of the medical devices, measured according to BS EN556-1:2001, for cell culture bags manufactured under the same conditions and sterilized with gamma rays at a dose of 25 kGy was 10 in all cases. -6 That was the case.

[0137] 2 x 10 7One human chronic myeloid leukemia cell line K562 (RIKEN BRC, RCB0027) was suspended in 100 ml of RPMI1640 medium (Fujifilm Wako Pure Chemical Industries) containing 10% FBS (BioWest), 1% GlutaMAX™-I supplement (Thermo Fisher Scientific), and 1% penicillin / streptomycin (Fujifilm Wako Pure Chemical Industries). The cells were introduced into the sterile cell culture bags with ports and cultured in a CO2 incubator maintained at 37°C and 5% CO2. Half of the culture medium was replaced using a syringe through the port 3, 5, 7, 10, and 12 days after the start of culture. The cell suspension was also collected using a syringe through the port 3, 7, 10, and 14 days after seeding.

[0138] Cell density and cell viability were calculated for cell suspensions 3, 7, 10, and 14 days after the start of culture using the trypan blue efflux method. Specifically, the cell suspension was mixed with a 0.4 w / v% trypan blue solution (Fujifilm Wako Pure Chemical Industries, Ltd.), injected into a cell counter (Funakoshi Co., Ltd.), and observed using a phase-contrast microscope (OLYMPUS Co., Ltd.) to count the cell density. Cell viability was classified as follows: cells that did not stain due to trypan blue efflux were classified as live cells, and cells stained blue with the dye were classified as dead cells. Cell viability was calculated using the formula: live cell density ÷ total cell (live cells + dead cells) density. The results are shown in Table 13.

[0139] [Table 13]

[0140] The results shown in Table 13 indicate that cell culture bags using multilayer film 36 have higher cell culture efficiency than cell culture bags using single-layer film 39. [Industrial applicability]

[0141] The multilayer film according to the present invention and the cell container having the same can be applied to the culture of various cells. [Explanation of Symbols]

[0142] 100 cell containers 110 Bag section 112, 114 multilayer film 116 Contact area 200 Port Components

Claims

1. A heat-seal layer containing polyolefin, A core layer containing styrene-based elastomer, The outer layer comprises a 4-methyl-1-pentene copolymer, The oxygen permeability at 23°C is 3.0 L / (m³). ２ ・day・atm) or more 100.0L / (m ２ (day ATM) is less than or equal to Multilayer film.

2. The aforementioned polyolefin includes an ethylene (co)polymer or a propylene (co)polymer. The multilayer film according to claim 1.

3. The aforementioned polyolefin includes a polyolefin having a melting point of 80°C or higher and 150°C or lower. The multilayer film according to claim 1.

4. The aforementioned polyolefin has a density of 890 kg / m³. ３ More than 930kg / m ３ The following polyolefins are included: The multilayer film according to claim 1.

5. The styrene-based elastomer has a content of styrene-derived constituent units of 5% by mass or more and 30% by mass or less relative to its total mass. The multilayer film according to claim 1.

6. The styrene-based elastomer is at least one styrene-based elastomer selected from the group consisting of hydrogenated styrene-butadiene-styrene block copolymer (HSBR), styrene-ethylene-butene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), and styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS). The multilayer film according to claim 1.

7. The outer layer or core layer comprises a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, or a copolymer of propylene and an α-olefin (excluding propylene) having 2 to 20 carbon atoms. The multilayer film according to claim 1.

8. The 4-methyl-1-pentene copolymer has a composition in which the amount of constituent units derived from 4-methyl-1-pentene is 80 mol% or more and 99 mol% or less of the total constituent units, and the amount of constituent units derived from α-olefins (excluding 4-methyl-1-pentene) having 4 to 20 carbon atoms is 1 mol% or more and 20 mol% or less of the total constituent units. The multilayer film according to claim 1.

9. The heat seal strength when the heat seal layers are heat-sealed together at 150°C is 10 N / 15 mm or more and 300 N / 15 mm or less. The multilayer film according to claim 1.

10. The thickness is between 20 μm and 1 mm. The multilayer film according to claim 1.

11. The ratio of the thickness of the heat seal layer to the thickness of the core layer is 1:10 or more and 5:1 or less. The multilayer film according to claim 1.

12. Used in the formation of cell vessels, The multilayer film according to claim 1.

13. One or more multilayer films according to any one of claims 1 to 12 are heat-sealed together to form a bag, container.

14. The container has a port member that connects the inside and outside of the container, The port member is bonded to the multilayer film in the heat-sealed portion of the heat-seal layer. The container according to claim 13.

15. The container according to claim 13, which is a cell container.

16. The sterility assurance level (SAL) of the medical device, as measured in accordance with BS EN556-1:2001, is 10. －３ The following is: The container according to claim 13.

17. A method for manufacturing a container, comprising the step of heat-sealing one or more multilayer films according to any one of claims 1 to 12 to form a bag.

18. A step of introducing cells into a cell container comprising a multilayer film according to any one of claims 1 to 12, The process of culturing cells in the aforementioned cell vessel, A method for culturing cells, comprising the following characteristics.

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