Laminated film, container, cell culture container, cell culture method, and method for manufacturing cell culture container

Abstract

A laminated film in which a first polyolefin resin layer containing a first polyolefin resin having a melting point of 95-200°C, a second polyolefin resin layer containing a second polyolefin resin having a melting point of lower than 95°C and a third polyolefin resin layer containing a third polyolefin resin having a melting point of 95-200°C are laminated in this order, and which has an oxygen permeability of from 7500 mL / m2·day·atm to 85000 mL / m2·day·atm.

Description

[Technical Field]

[0001] The present disclosure relates to a laminated film, a container, a cell culture container, a cell culture method, and a method for manufacturing a cell culture container. [Background technology]

[0002] Films using low-density resins have been developed, and films with excellent gas permeability can be obtained by using low-density resins. For example, 4-methyl-1-pentene polymers have bulky functional groups, which means that they have a lower density than other thermoplastic polyolefin laminate films. Therefore, laminate films containing 4-methyl-1-pentene polymers have high permeability to gases such as oxygen and carbon dioxide. Such laminate films can be used as gas-permeable laminate films for packaging fresh foods and the like. For example, Patent Document 1 describes a packaging bag for bulbs, which is made by molding a 4-methyl-1-pentene resin composition containing 99 to 70 parts by mass of a 4-methyl-1-pentene polymer and 1 to 30 parts by mass of a butene-1 solid polymer into a film having a crystallinity in the range of 25 to 35%, and then molding the film into a bag by a heat sealing method.

[0003] Patent document 1: Japanese Patent Application Laid-Open No. 11-301691 Summary of the Invention [Problem to be solved by the invention]

[0004] As mentioned above, from the viewpoint of excellent gas permeability, it is considered preferable to produce a film using a resin with a low density (for example, a low-density polyolefin resin). However, resins with low density tend to have low melting points. Even when attempting to manufacture a film using a resin with a low melting point, there were issues such as the resulting film being sticky at room temperature, the resin being unable to maintain its shape and thus the film itself could not be manufactured, and the heat sealability of the resulting film being low. That is, it was difficult to manufacture a film with maintained product quality using a resin with a low melting point. From the above, there is a demand to manufacture a film with excellent gas permeability using a resin with a low melting point.

[0005] The problem to be solved by one embodiment of the present disclosure is to provide a laminated film containing a low melting point polyolefin resin and having excellent gas permeability, and a method for manufacturing a container, a cell culture container, a cell culture method, and a cell culture container obtained from the above laminated film.

Means for Solving the Problem

[0006] The means for solving the above problems include the following aspects. <1> A first polyolefin resin layer containing a first polyolefin resin having a melting point of 95°C to 200°C, a second polyolefin resin layer containing a second polyolefin resin having a melting point of less than 95°C, and a third polyolefin resin layer containing a third polyolefin resin having a melting point of 95°C to 200°C are laminated in this order, and the oxygen permeability is 7500 mL / m 2 ·day·atm to 85000 mL / m 2 ·day·atm laminated film. <2> The laminated film according to <1>, having a total thickness of 15 μm or more and less than 150 μm. <3> The laminated film according to <1> or <2>, wherein the second polyolefin resin layer has a density measured in accordance with JIS K 7112 of 820 kg / m 3 or more and less than 890 kg / m 3 . <4> The laminated film according to any one of <1> to <3>, wherein the second polyolefin resin is an ethylene α-olefin copolymer having a melting point of less than 90°C. <5> The density of the first polyolefin resin layer and the third polyolefin resin layer, each measured in accordance with JIS K 7112, is 900 kg / m 3 or more and 980 kg / m 3 or less. The laminated film according to any one of <1> to <4>. <6> The carbon dioxide permeability is 35,000 mL / m 2 ·day·atm to 250,000 mL / m 2 ·day·atm. The laminated film according to any one of <1> to <5>. <7> At least one of the first polyolefin resin layer and the third polyolefin resin layer has a thickness of 5 μm to 100 μm. The laminated film according to any one of <1> to <6>. <8> The second polyolefin resin layer has a thickness of 5 μm to 100 μm. The laminated film according to any one of <1> to <7>. <9> The thickness ratio of the second polyolefin resin layer to the total thickness of the first polyolefin resin layer and the third polyolefin resin layer is 0.5 to 20.0. The laminated film according to any one of <1> to <8>. <10> The laminated film according to any one of <1> to <9>, which is formed by a coextrusion inflation film forming method, a coextrusion cast film forming method, or a coextrusion lamination forming method. <11> A container made of the laminated film according to any one of <1> to <10> and heat-sealed. <12> A cell culture container containing the laminated film according to any one of <1> to <10>. <13> The cell culture container according to <12>, which contains the laminated film at the bottom. <14> The cell culture container according to <12> or <13>, in which the ends of the laminated film are heat-sealed to form a bag. <15> The sterilization assurance level (SAL) of the medical device measured in accordance with BS EN 556 - 1:2001 is 10 -6 or less. The cell culture container according to <14>. <16> <12> ~ <15> 10. A cell culture method comprising the step of sealing and sealing cells in the cell culture vessel according to any one of the above items. <17> Contains a first polyolefin resin having a melting point of 95°C to 200°C First A method for manufacturing a cell culture vessel, comprising a film-forming step of co-extruding a polyolefin resin layer, a second polyolefin resin layer containing a second polyolefin resin having a melting point of less than 95°C, and a third polyolefin resin layer containing a third polyolefin resin having a melting point of 95°C to 200°C to obtain a laminated film. <18> Furthermore, the method includes a bag-making step of heat-sealing the edges of the obtained laminated film to form a bag. <17> A method for producing the cell culture vessel described in claim 1. <19> Further, the method includes a step of irradiating the obtained bag with gamma rays. <18> A method for producing the cell culture vessel described in claim 1. <20> In the film-forming process, a laminated film is obtained using an inflation molding machine. <17> ~ <19> 10. A method for producing a cell culture vessel according to any one of the preceding items. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, it is possible to provide a laminated film containing a low-melting point polyolefin resin and having excellent gas permeability, as well as a container, a cell culture vessel, a cell culture method, and a method for manufacturing a cell culture vessel obtained from the laminated film. DETAILED DESCRIPTION OF THE INVENTION

[0008] Specific embodiments of the present disclosure will be described in detail below, but the present disclosure is not limited to the following embodiments and can be implemented with appropriate modifications within the scope of the purpose of the present disclosure.

[0009] In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits. In this specification, unless otherwise specified, the "surface" of a member means the "main surface" of the member. In this specification, "adhesion" is a concept that includes "stickiness". In this specification, the "laminated film" is a concept that includes not only what is generally called a "film" but also what is generally called a "sheet". In this specification, when referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the multiple substances present in the composition.

[0010] ≪Laminated Film≫ The laminated film of the present disclosure includes a first polyolefin resin layer containing a first polyolefin resin having a melting point of 95°C to 200°C, a second polyolefin resin layer containing a second polyolefin resin having a melting point of less than 95°C, and a third polyolefin resin layer containing a third polyolefin resin having a melting point of 95°C to 200°C, which are laminated in this order, and the oxygen permeability is 7500 mL / m 2 ·day·atm to 85000 mL / m 2 ·day·atm.

[0011] Due to the above configuration, the laminated film of the present disclosure contains a low-melting polyolefin resin and has excellent gas permeability. As described above, from the viewpoint of excellent gas permeability, it is considered preferable to produce a film using a resin with a low density (for example, a low-density polyolefin resin). However, resins with a low density tend to have a low melting point. Even when trying to produce a film using a resin with a low melting point, there are problems such as the resin being unable to maintain its shape and the film itself cannot be produced, and it has been difficult to produce a film with maintained product quality using a resin with a low melting point.

[0012] Due to the above configuration, the laminated film of the present disclosure is non-sticky and can maintain its shape as a film. Further, the laminated film of the present disclosure has excellent gas permeability and excellent heat sealability.

[0013] The laminated film of the present disclosure has a first polyolefin resin layer, a second polyolefin resin layer, and a third polyolefin resin layer laminated in this order. That is, a laminated film is formed by sandwiching a second polyolefin resin layer having a low melting point (i.e., low density) between a first polyolefin resin layer and a third polyolefin resin layer having a high melting point (i.e., high density). The laminated film of the present disclosure contains a second polyolefin resin layer having a low melting point (i.e., low density), and thus has excellent gas permeability. Further, by sandwiching the second polyolefin resin layer between a first polyolefin resin layer and a third polyolefin resin layer having a high melting point (i.e., high density), there is no stickiness and the shape of the film can be maintained.

[0014] -Gas permeability- (Oxygen permeability) The oxygen permeability of the laminated film of the present disclosure is 7500 mL / m 2 ·day·atm to 85000 mL / m 2 ·day·atm. The oxygen permeability of the laminated film of the present disclosure is preferably 7500 mL / m from the viewpoint of long-term preservation of fruits and vegetables, flowers, microorganisms, etc. 2 ·day·atm to 80000 mL / m 2 ·day·atm, and more preferably 10000 mL / m 2 ·day·atm to 50000 mL / m 2 ·day·atm.

[0015] (Carbon dioxide permeability) The carbon dioxide permeability of the laminated film of the present disclosure is not particularly limited. The carbon dioxide permeability of the laminated film of the present disclosure is preferably 8000 mL / m from the viewpoint of long-term preservation of fruits and vegetables, flowers, microorganisms, etc. 2 ·day·atm to 250000 mL / m 2 ·day·atm, and more preferably 35000 mL / m 2 ·day·atm to 250000 mL / m2 ·day·atm, more preferably 50000 mL / m 2 ·day·atm~230000 mL / m 2 ·day·atm, particularly preferably 50000 mL / m 2 ·day·atm~200000 mL / m 2 ·day·atm, even more preferably 50000 mL / m 2 ·day·atm~150000 mL / m 2 ·day·atm.

[0016] (Hydrogen permeability) The hydrogen permeability in the laminated film of the present disclosure is not particularly limited. The hydrogen permeability in the laminated film of the present disclosure is preferably 10000 mL / m from the viewpoint of being suitably used for hydrogen battery-related members such as hydrogen separation membranes and hydrogen permeation membranes. 2 ·day·atm~300000 mL / m 2 ·day·atm, more preferably 50000 mL / m 2 ·day·atm~230000 mL / m 2 ·day·atm, even more preferably 50000 mL / m 2 ·day·atm~200000 mL / m 2 ·day·atm, particularly preferably 50000 mL / m 2 ·day·atm~150000 mL / m 2 ·day·atm.

[0017] The laminated film of the present disclosure has an oxygen permeability of 7500 mL / m 2 ·day·atm~85000 mL / m 2 ·day·atm, and a carbon dioxide permeability of 8000 mL / m 2 ·da y·atm~250000 mL / m 2 ·day·atm, and a hydrogen permeability of 10000 mL / m 2 ·day·atm~300000 mL / m 2 ·day·atm is preferred.

[0018] Oxygen permeability of the laminated film (unit: mL / m 2 ·day·atm), carbon dioxide permeability (unit: mL / m 2 ·day·atm), and hydrogen permeability (unit: mL / m 2 ·day·atm) can be measured by JIS K7126-1 (differential pressure method), JIS K7126-2 (isobaric method), etc. For example, the oxygen permeability of the laminated film (unit: mL / m 2 ·day·atm), carbon dioxide permeability (unit: mL / m 2 ·day·atm), and hydrogen permeability (unit: mL / m 2 ·day·atm) can be measured under the following conditions.

[0019] Measuring device; Isobaric gas permeability measuring device (GTR-10XFKS manufactured by GTR Tech Co., Ltd.) Test piece; 50 mmφ Detector; Gas chromatograph method Test gas; Various gases (carbon dioxide, oxygen or hydrogen) Measuring temperature; 23°C Permeation area; 35 mmφ

[0020] <First polyolefin resin layer> The first polyolefin resin layer contains a first polyolefin resin having a melting point of 95°C to 200°C. By including the first polyolefin resin layer, the laminated film of the present disclosure can maintain its shape as a film. Also, stickiness can be suppressed. By including the first polyolefin resin layer and the third polyolefin resin layer described later, the laminated film of the present disclosure has excellent heat sealability.

[0021] The thickness of the first polyolefin resin layer is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less, and even more preferably 3 μm or more and 12 μm or less. Thereby, it is excellent in heat seal strength when heat-sealed.

[0022] In the present disclosure, the thickness of the resin layer is measured using a contact type thickness meter (Model H manufactured by Peacock Co., Ltd.).

[0023] The first polyolefin resin has a melting point of 95° C. to 200° C. This allows the laminate film of the present disclosure to maintain its shape as a film and also reduces stickiness. From the above viewpoints, the melting point of the first polyolefin resin is preferably 95°C to 200°C, more preferably 100°C to 190°C, and even more preferably 110°C to 180°C.

[0024] The first polyolefin resin layer has a density of 900 kg / m as measured in accordance with JIS K 7112 (1999). 3 More than 980kg / m 3 It is preferable that: The density of the first polyolefin resin layer is 900 kg / m 3 By satisfying the above conditions, the resulting laminated film can maintain its shape as a film. The density of the first polyolefin resin layer is 980 kg / m 3 When the thickness is less than 1 / 2 mm, the obtained laminated film has excellent heat sealability. From the above viewpoint, the first polyolefin resin layer has a density measured in accordance with JIS K 7112 (1999) of 905 kg / m 3 More than 950kg / m 3 Is less than or equal to More preferably, 910 kg / m 3 More than 930kg / m 3 It is even more preferable that:

[0025] The first polyolefin resin is not particularly limited as long as its melting point falls within the above range. For example, the first polyolefin resin may be an ethylene homopolymer, a propylene homopolymer, an α-olefin copolymer, or the like.

[0026] Examples of ethylene homopolymers include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and high-density polyethylene (HDPE).

[0027] Examples of the α-olefin copolymer include copolymers of two or more monomers selected from the group consisting of ethylene, propylene, 1-butene, 1-hexene, and 1-octene. Examples of ethylene-α-olefin copolymers include copolymers of ethylene and one or more monomers selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene. The first polyolefin resin may be used alone or in combination of two or more kinds.

[0028] The first polyolefin resin may include at least one selected from the group consisting of unsaturated carboxylic acid-modified ethylene-α-olefin copolymer, ethylene-unsaturated carboxylic acid copolymer, ethylene-vinyl acetate copolymer, silane-modified ethylene-vinyl acetate copolymer, ionomer of unsaturated carboxylic acid-modified ethylene-α-olefin copolymer, and ionomer of ethylene-unsaturated carboxylic acid copolymer, and preferably includes an ethylene-unsaturated carboxylic acid copolymer or an ionomer thereof.

[0029] (Unsaturated carboxylic acid modified ethylene-α-olefin copolymer) The ethylene-α-olefin copolymer used in the unsaturated carboxylic acid-modified ethylene-α-olefin copolymer may be, for example, a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Among the above, from the viewpoint of adhesive strength, the α-olefin having 3 to 20 carbon atoms is preferably propylene, 1-butene, 1-hexene or 1-octene, and more preferably 1-butene, 1-hexene or 1-octene.

[0030] The molar ratio of ethylene to α-olefin in the ethylene-α-olefin copolymer is preferably in the range of 45 / 55 to 95 / 5.

[0031] In the present disclosure, the unsaturated carboxylic acid used for modification includes unsaturated carboxylic acids and derivatives thereof.

[0032] The unsaturated carboxylic acid used for modification may be an unsaturated carboxylic acid or a derivative thereof, such as maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, Nadic acid (registered trademark, endo-cis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid), acrylic acid, or methacrylic acid, or a derivative thereof. Examples of the derivatives of the unsaturated carboxylic acids include acid anhydrides, imides, amides, and esters of unsaturated carboxylic acids.

[0033] Specific examples of the derivatives of unsaturated carboxylic acids include maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, and glycidyl maleate. Among the above, the unsaturated carboxylic acid used for modification is preferably an unsaturated carboxylic acid or an anhydride thereof, and more preferably maleic acid, maleic anhydride, nadic acid, or nadic anhydride.

[0034] The unsaturated carboxylic acid modification may be carried out by a graft reaction of the unsaturated carboxylic acid. As a method for producing a modified product by graft copolymerization using the unsaturated carboxylic acid or a derivative thereof as a graft monomer, a conventionally known method can be used. For example, a melt modification method in which an ethylene-α-olefin copolymer is melted, a graft monomer is added, and graft copolymerization is carried out, or a solution modification method in which an ethylene-α-olefin copolymer is dissolved in a solvent, a graft monomer is added, and graft copolymerization is carried out can be used.

[0035] When carrying out graft copolymerization, from the viewpoint of efficiency, it is preferable to carry out the reaction in the presence of a radical initiator. The content of the radical initiator may be in the range of 0.001 parts by mass to 2 parts by mass with respect to 100 parts by mass of the ethylene-α-olefin copolymer which is the base polymer.

[0036] Examples of the radical initiator include organic peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 1,4-bis(tert-butylperoxyisopropyl)benzene.

[0037] In the unsaturated carboxylic acid-modified ethylene-α-olefin copolymer in the present disclosure, the modification amount may be 0.01% by mass to 10% by mass, preferably 0.1% by mass to 5% by mass, and more preferably 1% by mass to 5% by mass with respect to the total amount of the unsaturated carboxylic acid-modified ethylene-α-olefin copolymer.

[0038] The unsaturated carboxylic acid-modified ethylene-α-olefin copolymer preferably has a melt flow rate (MFR) in the range of 0.05 g / 10 min to 200 g / 10 min, more preferably in the range of 0.1 g / 10 min to 100 g / 10 min when measured according to ASTM D1238 under the conditions of a temperature of 190°C and a load of 2.16 kg.

[0039] Also, the unsaturated carboxylic acid-modified ethylene-α-olefin copolymer may have a crystallinity of 30% or less as measured by X-ray.

[0040] (Ethylene-unsaturated carboxylic acid copolymer) The ethylene-unsaturated carboxylic acid copolymer is a copolymer containing structural units derived from ethylene and structural units derived from an unsaturated carboxylic acid. The ethylene-unsaturated carboxylic acid copolymer in the present disclosure may be a copolymer of ethylene and an unsaturated carboxylic acid, or a copolymer of ethylene, an unsaturated carboxylic acid and other monomers, or a polymer obtained by modifying an ethylene polymer with an unsaturated carboxylic acid. Examples of the ethylene-unsaturated carboxylic acid copolymer include ethylene-unsaturated carboxylic acid binary copolymers and their ionomers, ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester terpolymers and their ionomers, ethylene-unsaturated carboxylic acid ester binary copolymers Among them, from the viewpoints of interlayer adhesion strength and heat seal strength, ethylene-unsaturated carboxylic acid-unsaturated carboxylic acid ester terpolymers and their ionomers are preferred.

[0041] The ethylene-unsaturated carboxylic acid copolymer can be obtained, for example, by subjecting ethylene and an unsaturated carboxylic acid to a radical polymerization reaction under high temperature and high pressure in the presence of an organic peroxide or oxygen.

[0042] Examples of the unsaturated carboxylic acid include ethyl acrylate, methacrylic acid, methyl methacrylate, vinyl acetate, vinyl chloride, and the like. Among these, from the viewpoint of excellent heat resistance and ability to perform high-temperature processing, at least one selected from the group consisting of ethyl acrylate, methacrylic acid, methyl methacrylate, and vinyl acetate is preferred, and at least one selected from the group consisting of ethyl acrylate, methacrylic acid, and methyl methacrylate is more preferred.

[0043] As the ethylene-unsaturated carboxylic acid copolymer, a copolymer of ethylene and ethyl acrylate (also referred to as EEA in the present disclosure) can be used. In the EEA, the content of ethyl acrylate may be 10% by mass to 40% by mass, and preferably 15% by mass to 30% by mass, from the viewpoints of moldability and interlayer adhesive strength. The melt flow rate (measured in accordance with ASTM D1238 at a temperature of 190°C and a load of 2.16 kg) may be 5 g / 10 min to 50 g / 10 min, and preferably 10 g / 10 min to 30 g / 10 min, from the viewpoints of moldability and interlayer adhesive strength.

[0044] As the ethylene-unsaturated carboxylic acid copolymer, a copolymer of ethylene and methacrylic acid (also referred to as EMAA in the present disclosure) can be used. In the ethylene-methacrylic acid copolymer, the content of methacrylic acid may be 10% by mass to 40% by mass, and preferably 3% by mass to 10% by mass, from the viewpoints of moldability and interlayer adhesive strength. The melt flow rate (measured in accordance with ASTM D1238 at a temperature of 190°C and a load of 2.16 kg) may be 5 g / 10 min to 100 g / 10 min, and preferably 10 g / 10 min to 80 g / 10 min, from the viewpoints of moldability and interlayer adhesive strength. Commercially available products include Nucrel (registered trademark) manufactured by Mitsui-Dow Polychemicals.

[0045] (Ethylene-vinyl acetate copolymer and silane-modified ethylene-vinyl acetate copolymer) Ethylene-vinyl acetate copolymer (also known as EVA) is a copolymer of ethylene and vinyl acetate. Silane-modified ethylene-vinyl acetate copolymer (also called silane-modified EVA) is a compound obtained by modifying EVA.

[0046] From the viewpoint of adhesive strength, the content of vinyl acetate in EVA is preferably 10% by mass to 50% by mass. EVA has a density of 930 kg / m 3 ~980kg / m 3 It is preferable that the range is: The EVA preferably has a melt flow rate (MFR) of 0.8 g / 10 min to 30 g / 10 min at 190 °C under a load of 2.16 kg. As the ethylene-vinyl acetate copolymer, those produced by a conventionally known method may be appropriately used, or commercially available products may be used.

[0047] The silane compound used for modifying EVA is preferably an organosilicon compound having one or more unsaturated hydrocarbon groups and one or more alkoxy groups in the molecule. preferably Examples of the unsaturated hydrocarbon group include a vinyl group, an allyl group, a (meth)acrylic group, etc., and examples of the alkoxy group include a methoxy group, an ethoxy group, a butoxy group, etc. As the silane compound, for example, vinyltrimethoxysilane and vinyltriethoxysilane in which the unsaturated hydrocarbon group is a vinyl group and the alkoxy group is a methoxy group or an ethoxy group are preferable.

[0048] The content of the silane compound in the silane-modified EVA is preferably 0.01 part by mass to 5.0 parts by mass with respect to 100 parts by mass of EVA.

[0049] The silane-modified EVA in the present disclosure may be a compound obtained by graft-modifying EVA with a silane compound. For example, the silane-modified EVA can be obtained by adding a silane compound and a radical generator to EVA in an extruder, melt-kneading at a temperature and for a time equal to or higher than the thermal decomposition start temperature of the radical generator, and then pelletizing.

[0050] The radical generator is a compound that decomposes by heating to generate free radicals and is used as a reaction initiator for chemically bonding the silane compound to EVA. As the radical generator, those having a half-life of 3 minutes or less at a temperature equal to or higher than the melting point of EVA and equal to or lower than 150 °C are particularly preferable.

[0051] Examples of the radical generator include peroxides such as benzoyl peroxide, lauroyl peroxide, t-butyl peracetate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxyisobutyrate, and dicumyl peroxide. The content of the radical generator may be appropriately adjusted according to the type of EVA and the amount of the silane compound used. For example, the content of the radical generator is preferably 0.01 to 5.0 parts by mass with respect to 100 parts by mass of EVA. In addition, in order to suppress the polymerization between the silane compounds, a reaction inhibitor such as mercaptan may be added.

[0052] Among the above, the first polyolefin resin is preferably at least one selected from the group consisting of an ethylene homopolymer, a propylene homopolymer, and an ethylene α-olefin copolymer which is a copolymer of ethylene and one or more α-olefins having 3 to 8 carbon atoms, and more preferably at least one selected from the group consisting of low-density polyethylene and linear low-density polyethylene.

[0053] <Second Polyolefin Resin Layer> The second polyolefin resin layer contains a second polyolefin resin having a melting point of less than 95°C. By including the second polyolefin resin layer, the laminated film of the present disclosure can improve gas permeability. In addition, by including the second polyolefin resin layer, the laminated film of the present disclosure is excellent in resistance to low temperatures (also referred to as low-temperature characteristics). For example, when storing contents such as cells in refrigeration or freezing using the laminated film of the present disclosure, cracks, delamination, etc. at low temperatures are suppressed.

[0054] The second polyolefin resin layer preferably has a thickness of 5 to 100 μm, more preferably 7 to 50 μm, and even more preferably 9 to 30 μm. Yes.

[0055] In the present disclosure, the thickness of the resin layer is measured using a contact thickness gauge (MODEL H manufactured by Peacock).

[0056] The second polyolefin-based resin has a melting point of less than 95°C. Thereby, the laminated film of the present disclosure can improve gas permeability. From the above viewpoints, the second polyolefin-based resin preferably has a melting point of 90°C or lower, and more preferably 85°C or lower.

[0057] The second polyolefin-based resin layer has a density measured in accordance with JIS K 7112 (1999) of 800 kg / m 3 or more and 900 kg / m 3 less. When the density of the second polyolefin-based resin layer is 800 kg / m 3 or more, the obtained laminated film can maintain its shape as a film. When the density of the second polyolefin-based resin layer is less than 900 kg / m 3 the obtained laminated film is excellent in gas permeability. From the above viewpoints, the second polyolefin-based resin layer preferably has a density measured in accordance with JIS K 7112 (1999) of 820 kg / m 3 or more and 890 kg / m 3 less, more preferably 830 kg / m 3 or more and 890 kg / m 3 less, and even more preferably 850 kg / m 3 or more and 888 kg / m 3 less.

[0058] The second polyolefin-based resin is not particularly limited as long as its melting point satisfies the above range. For example, examples of the second polyolefin-based resin include an ethylene homopolymer, a propylene homopolymer, an α-olefin copolymer, etc., similar to the above-described first polyolefin-based resin. Details of specific examples, specific aspects, preferred aspects, etc. of the ethylene homopolymer, propylene homopolymer, and α-olefin copolymer in the second polyolefin resin are the same as the details of specific examples, specific aspects, preferred aspects, etc. of the ethylene homopolymer, propylene homopolymer, and α-olefin copolymer described in the section on the first polyolefin resin.

[0059] The second polyolefin resin is preferably at least one selected from the group consisting of ethylene homopolymers and ethylene-α-olefin copolymers, which are copolymers of ethylene and one or more α-olefins having 3 to 8 carbon atoms; More preferably, it is at least one selected from the group consisting of ethylene homopolymers and ethylene-1-butene copolymers, which are copolymers of ethylene and 1-butene. The second polyolefin resin is preferably an ethylene-α-olefin copolymer having a melting point of less than 90°C.

[0060] <Third polyolefin resin layer> The third polyolefin resin layer contains a third polyolefin resin having a melting point of 95°C to 200°C. By including the third polyolefin resin layer, the laminate film of the present disclosure can maintain its shape as a film and can also be made less sticky. The third polyolefin resin in the present disclosure and the first polyolefin resin in the present disclosure may be the same resin or different resins, but are preferably the same resin.

[0061] The thickness of the third polyolefin resin layer is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less, and even more preferably 3 μm or more and 12 μm or less. This results in excellent heat sealing strength when heat sealed.

[0062] In the present disclosure, the thickness of the resin layer is measured using a contact type thickness meter (Model H manufactured by Peacock Co., Ltd.).

[0063] The third polyolefin resin has a melting point of 95° C. to 200° C. This allows the laminate film of the present disclosure to maintain its shape as a film and also reduces stickiness. From the above viewpoints, the melting point of the third polyolefin resin is preferably 95°C to 200°C, more preferably 100°C to 190°C, and even more preferably 110°C to 180°C.

[0064] The third polyolefin resin layer has a density of 900 kg / m as measured in accordance with JIS K 7112 (1999). 3 More than 980kg / m 3 It is preferable that: The density of the third polyolefin resin layer is 900 kg / m 3 By satisfying the above conditions, the resulting laminated film can maintain its shape as a film. The density of the third polyolefin resin layer is 980 kg / m 3 When the thickness is less than 1 / 2 mm, the obtained laminated film has excellent heat sealability. From the above viewpoint, the third polyolefin resin layer has a density of 905 kg / m as measured in accordance with JIS K 7112 (1999). 3 More than 950kg / m 3 More preferably, it is 910 kg / m or less. 3 More than 930kg / m 3 It is even more preferable that:

[0065] The third polyolefin resin is not particularly limited as long as its melting point falls within the above range. For example, the third polyolefin resin may be an ethylene homopolymer, a propylene homopolymer, an α-olefin copolymer, or the like, similar to the first polyolefin resin. Details such as specific examples, specific embodiments, and preferred embodiments of the ethylene homopolymer, propylene homopolymer, and α-olefin copolymer in the third polyolefin resin are the same as the details of the ethylene homopolymer, propylene homopolymer, and α-olefin copolymer described in the section on the first polyolefin resin, including specific examples, specific embodiments, and preferred embodiments.

[0066] Among the above, the third polyolefin resin is preferably at least one selected from the group consisting of an ethylene homopolymer, a propylene homopolymer, and an ethylene α-olefin copolymer which is a copolymer of ethylene and one or more α-olefins having 3 to 8 carbon atoms, and more preferably at least one selected from the group consisting of low-density polyethylene and linear low-density polyethylene.

[0067] The density of the first polyolefin resin layer and the third polyolefin resin layer, each measured in accordance with JIS K 7112, is preferably 900 kg / m 3 or more and 980 kg / m 3 or less. That is, it is more preferable that both the first polyolefin resin layer and the third polyolefin resin layer have a density measured in accordance with JIS K 7112 of 900 kg / m 3 or more and 980 kg / m 3 or less.

[0068] The first polyolefin resin and the third polyolefin resin are each independently preferably at least one selected from the group consisting of an ethylene homopolymer, a propylene homopolymer, and an ethylene α-olefin copolymer which is a copolymer of ethylene and one or more α-olefins having 3 to 8 carbon atoms.

[0069] At least one of the first polyolefin resin layer and the third polyolefin resin layer preferably has a thickness of 5 μm to 100 μm, and more preferably both the first polyolefin resin layer and the third polyolefin resin layer have a thickness of 5 μm to 100 μm.

[0070] The thickness ratio (second / first·third) of the second polyolefin resin layer to the total thickness of the first polyolefin resin layer and the third polyolefin resin layer is preferably 0.5 to 20.0. When the thickness ratio (second / first·third) is within the above range, the gas permeability and shape retention of the film can be adjusted in a well-balanced manner in the obtained laminated film. From the above viewpoint, the thickness ratio (second / first·third) is more preferably 0.7 to 10.0, and further preferably 1.0 to 5.0.

[0071] The laminated film of the present disclosure preferably has a total thickness of 15 μm or more and less than 150 μm, more preferably 20 μm or more and 100 μm or less, and even more preferably 25 μm or more and 60 μm or less.

[0072] The first to third polyolefin resins in the present disclosure may be the same resin or different resins, but are preferably the same resin. In the present disclosure, the first polyolefin resin, the second polyolefin resin, and the third polyolefin resin are the same resin, which results in excellent recyclability.

[0073] [Method for producing laminated film] The method for producing the laminated film of the present disclosure is not particularly limited, and for example, a method in which the layers contained as constituent components of the laminated film of the present disclosure are mixed near the interfaces to adhere to each other, thereby forming the laminated film, is preferred. Examples of such a method include a co-extrusion method in which molten resins are laminated, and a heat fusion method in which pre-formed resin laminate films are heat-fused. Among these methods, the co-extrusion method in which molten resins are laminated is more preferred from the viewpoint of forming a laminated film in which the interlayer adhesive strength of each layer is higher and interlayer delamination is less likely to occur.

[0074] The laminated film of the present disclosure is preferably formed by a coextrusion inflation film forming method, a coextrusion cast film forming method, or a coextrusion lamination forming method.

[0075] Before laminating each layer in the laminated film of the present disclosure, it is preferable to perform, for example, a surface treatment on a specific layer. By performing a surface treatment, better interlayer adhesion strength can be obtained. Examples of the surface treatment include corona treatment, ozone treatment, and the like. The corona treatment can be performed using, for example, a corona master (e.g., PS-10S manufactured by Shin-Ko Electric Co., Ltd.). The ozone treatment can be performed using a UV ozone cleaner (e.g., UV42 manufactured by Nippon Laser & Electronics Co., Ltd.).

[0076] 〔Applications of the laminated film〕 The laminated film of the present disclosure can be widely used, for example, as tapes, adhesive tapes, masking tapes, masking laminated films, temporarily adherable laminated films, freshness-retaining packaging laminated films, plastic envelopes, easy-open packaging bags, automatic packaging laminated films, shopping bags, standing bags, liquid laminated film containers, transparent packaging boxes, building materials, laminating films for bonding, agricultural laminated films, food packaging materials, fruit packaging materials, flower packaging materials, electronic component packaging materials, mechanical component packaging materials, cereal packaging materials, fishery product packaging materials such as fish and shellfish, medical laminated films, medical tapes, packs for plant cell culture, packs for seedling storage and cultivation, packs for animal cell culture, carbon dioxide separation membranes, hydrogen separation membranes, oxygen addition films, and the like.

[0077] ≪Container≫ The container of the present disclosure is made of the laminated film of the present disclosure and is heat-sealed. The container is not particularly limited in shape or the like as long as it can accommodate the contents inside. The shape of the container may be, for example, bag-shaped.

[0078] The container of the present disclosure may be, for example, a container for storing food, fruits and vegetables, flowers, seeds and seedlings, microorganisms, cells, etc. Among the above, the vessel is preferably a cell culture vessel.

[0079] ≪Cell culture container≫ The cell culture vessel of the present disclosure includes the laminate film of the present disclosure. The laminate film of the present disclosure contains a low-melting-point polyolefin resin and has excellent gas permeability. Therefore, a cell culture vessel containing the laminate film of the present disclosure also has excellent gas permeability. This allows the internal oxygen concentration to be maintained at a good level even during cell culture. Conventionally, the oxygen concentration inside the container has been maintained, for example, by periodically injecting oxygen into the container during cell culture. However, since the cell culture container of the present disclosure exhibits excellent gas permeability, it is presumed that periodically injecting oxygen into the container is not necessarily required.

[0080] Examples of cell culture vessels include cell culture packs. The cell culture vessel of the present disclosure may be made of the laminate film of the present disclosure, or may include the laminate film of the present disclosure as a part thereof. The cell culture vessel of the present disclosure preferably includes the laminate film of the present disclosure at the bottom.

[0081] The shape of the cell culture vessel of the present disclosure is not particularly limited. In the cell culture vessel of the present disclosure, the edges of the laminated film are preferably heat-sealed to form a bag. The cell culture vessel of the present disclosure preferably has a shape that can be sealed. For example, a culture vessel having a laminated film with its edges heat-sealed to form a bag may include a port for introducing and removing samples.

[0082] The cell culture vessels of the present disclosure have a sterility assurance level (SAL) of 10 for medical devices measured in accordance with BS EN 556-1:2001. -6 It is preferable that: When the SAL is within the above range, it is considered that there are no viable microorganisms inside the container, indicating excellent sterility.

[0083] ≪Cell culture method≫ The cell culture method of the present disclosure includes a step of enclosing cells in the cell culture container of the present disclosure and sealing it. As described above, since the cell culture container of the present disclosure exhibits excellent gas permeability, it is presumed that it is not always necessary to periodically inject oxygen into the container. Therefore, once the step of enclosing cells in the cell culture container of the present disclosure and sealing it is completed, it is considered that cells can be cultured without periodically injecting oxygen into the container thereafter.

[0084] ≪Method for manufacturing a container for cell culture≫ The method for manufacturing a container for cell culture of the present disclosure includes a first polyolefin resin having a melting point of 95°C to 200°C First a polyolefin resin layer, a second polyolefin resin layer containing a second polyolefin resin having a melting point of less than 95°C, and a third polyolefin resin layer containing a third polyolefin resin having a melting point of 95°C to 200°C, and includes a film forming step of co-extruding to obtain a laminated film.

[0085] In the film forming step of the method for manufacturing a container for cell culture of the present disclosure, it is preferable to obtain a laminated film using an inflation molding machine such as a T-die extrusion molding machine or an extrusion lamination molding machine. The molding conditions for inflation molding can be appropriately selected. As the molding conditions, for example, the following conditions may be used. ~Molding conditions~ Molding machine: 3-layer inflation molding machine (manufactured by Alpine: 3 sets of 50 mmφ extruders) Die: 225 mmφ (diameter), 3.5 mm (lip width) Air ring: 2-gap type Molding temperature: 200°C Extrusion rate: (1st layer (outermost layer): 5.3 kg / hr, 2nd layer (middle layer): 10.2 / hr, 3rd layer (innermost layer): 5.3 kg / hr) Take-up speed: 10m / min

[0086] The method for producing a cell culture vessel of the present disclosure preferably further includes a bag-making step of heat-sealing the edges of the obtained laminated film to form a bag. The heat sealing temperature is preferably 100°C to 200°C, more preferably 110°C to 170°C, and even more preferably 120°C to 150°C.

[0087] The specific form of heat sealing is not particularly limited, but may be, for example, the following form. Two sheets of laminated film were prepared, and the faces of the laminated films were placed facing each other. The edges were heat-sealed at a heat-sealing temperature of 140°C, a pressure of 0.2 MPa, a sealing time of 1 second, and a sealing bar width of 5 mm, and then the heat was released.

[0088] The method for producing a cell culture vessel according to the present disclosure preferably further comprises a step of irradiating the obtained bag with gamma rays. The inside of the bag can be sterilized by irradiating it with gamma rays, making it an excellent quality container for cell culture. Also, The absorbed dose of gamma rays is preferably 5 kGy to 50 kGy, and the sterility assurance level (SAL) of the medical device of the cell culture vessel is 10 -6 It is preferable to continue until the following occurs: [Example]

[0089] Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to the following examples as long as it does not deviate from the gist of the disclosure.

[0090] The following materials were used in this example: [Polyolefin] LLDPE: C6-linear low-density polyethylene copolymer (Evolue SP2020 manufactured by Prime Polymer Co., Ltd., melting point 116 °C, density 916 kg / m 3 ) PO1: Linear low-density polyethylene copolymer (Affinity (registered trademark) VP 8770G1 manufactured by Dow Chemical Japan Co., Ltd., melting point 82 °C, density 886 kg / m 3 ) PO2: Ethylene-butene copolymer (Tafmer (registered trademark) DF640 manufactured by Mitsui Chemicals, Inc., melting point 50 °C or lower, density 864 kg / m 3 )

[0091] [Laminated film] [Example 1] Using the polyolefins described in Table 1, an inflation film forming method was performed under the following forming conditions to produce a three-layer laminated film with a thickness of 30 μm and a width of 600 mm. In the laminated film, the thickness ratio of the first polyolefin resin layer (also referred to as the 1st PO layer), the second polyolefin resin layer (also referred to as the 2nd PO layer), and the third polyolefin resin layer (also referred to as the 3rd PO layer) (1st PO layer: 2nd PO layer: 3rd PO layer) is as described in Table 1.

[0092] ~Forming conditions~ Forming machine: Three-layer inflation forming machine (manufactured by Alpine: Three 50 mmφ extruders) Die: 225 mmφ (diameter), 3.5 mm (lip width) Air ring: 2-gap type Forming temperature: 200 °C Extrusion rate: (1st PO layer (outermost layer): 5.3 kg / hr, 2nd PO layer (intermediate layer): 10.2 / hr, 3rd PO layer (innermost layer): 5.3 kg / hr) Take-up speed: 10 m / min

[0093] [Example 2] A three-layer laminated film was produced in the same manner as in Example 1, except that the extrusion rates of the 1st PO layer, the 2nd PO layer, and the 3rd PO layer were changed to 4.3 kg / hr, 12.2 kg / hr, and 4.3 kg / hr, respectively. In the laminated film, the thickness ratio (first PO layer: second PO layer: third PO layer) is as described in Table 1.

[0094] <Example 3> A three-layer laminated film was produced in the same manner as in Example 1, except that the extrusion amounts of the first PO layer, the second PO layer, and the third PO layer were changed to 3.1 kg / hr, 14.6 kg / hr, and 3.1 kg / hr, respectively. In the laminated film, the thickness ratio (first PO layer: second PO layer: third PO layer) is as described in Table 1.

[0095] <Example 4> Using the polyolefin described in Table 1, a cast film forming method was performed under the following molding conditions to produce a three-layer laminated film with a thickness of 30 μm and a width of 720 mm. In the laminated film, the thickness ratio (first PO layer: second PO layer: third PO layer) is as described in Table 1.

[0096] ~Molding Conditions~ Molding machine; 50 mmφ multi-layer cast film molding machine with a T-die (manufactured by Sumitomo Heavy Industries Modern Co., Ltd.: 50 mmφ extruder, two 40 mmφ extruders) Cylinder temperature; 200 °C Chill roll temperature; 18 °C Take-up speed: 30 m / min

[0097] <Example 5> Using the laminated film obtained in Example 3, the laminated film was cut into a rectangular shape, an inlet port and an outlet port were provided on one side, and the peripheral ends of the laminated film on the rectangle were heat-sealed at 140 °C with a width of 5 mm to produce a cell culture bag with a capacity of 1000 mL. The obtained cell culture bag was irradiated with gamma rays, and it was confirmed that the sterility assurance level (SAL) of the medical device measured in accordance with BS EN 556-1:2001 was 10 -6 or less. The sterilized cell culture bag was confirmed to have no discoloration or the like and had a good appearance.

[0098] <Comparative Example 1> A monolayer film having only a first PO layer was produced in the same manner as in Example 1, except that the polyolefins shown in Table 1 were used and the second and third PO layers were not provided.

[0099] <Comparative Example 2> An attempt was made to produce a monolayer film having only the second PO layer in the same manner as in Example 1, except that the polyolefins listed in Table 1 were used and the first and third PO layers were not provided. However, it was sticky and could not be made into a film, so it was not possible to produce a monolayer film having only the second PO layer.

[0100] [evaluation] (gas permeability) Oxygen permeability of laminated film (unit: mL / m 2 day atm), carbon dioxide permeability (unit: mL / m 2 ·day·atm) and hydrogen permeability (unit: mL / m 2 ·day·atm) is measured under the following conditions. Carbon dioxide permeability is 70,000 mL / m 2 ·day·atm or more, and oxygen permeability is 20000mL / m 2 ·day·atm or more, and hydrogen permeability is 10,000mL / m 2 ·day·atm or higher means that the laminated film has excellent gas permeability.

[0101] Measurement equipment: isobaric gas permeability measurement equipment (GTR-10XFKS manufactured by GTR Tech Co., Ltd.) Test piece: 50 mm diameter Detector: Gas chromatographic method Test gas: various gases (carbon dioxide, oxygen or hydrogen) Measurement temperature: 23℃ Transmission area; 35mmφ

[0102] (heat sealability) The heat sealability of the film was evaluated by the following method. Two films were prepared, and placed face to face, and heat-sealed at a temperature of 140°C, a pressure of 0.2 MPa, a sealing time of 1 second, and a seal bar width of 5 mm, followed by dissipation of heat. Next, a 15 mm wide test piece was cut from the heat-sealed test piece, and the heat-sealed portion was peeled off at a crosshead speed of 300 mm / min, measuring the peel strength. The heat-sealability was evaluated using this value as the heat-seal strength. ~Evaluation Criteria~ A: 5N / 15mm or more B: Less than 5N / 15mm

[0103] (Low temperature characteristics) Using a Gelbo Flex Tester manufactured by Tester Sangyo Co., Ltd., test pieces measuring 210 mm wide and 297 mm long were cut out from the films obtained in each of the Examples and Comparative Examples, and a bending test was carried out 1,000 times at a bending angle of 440° and a bending speed of 40 times / min in an atmosphere of 4° C. Thereafter, bags were made from the test pieces, and the number of pinholes was measured using an Ageless Seal Check manufactured by Mitsubishi Gas Chemical Company, Inc., and the bags were evaluated according to the following evaluation criteria. ~Evaluation Criteria~ A: 50 pinholes / m 2 It was less than. B: 50 pinholes / m 2 That was all.

[0104] [Table 1]

[0105] As shown in Table 1, a first polyolefin resin layer containing a first polyolefin resin having a melting point of 95°C to 200°C, a second polyolefin resin layer containing a second polyolefin resin having a melting point of less than 95°C, and a third polyolefin resin having a melting point of 95°C to 200°C. In the example using the laminated film in which the second PO layer contained a low-melting point polyolefin resin and the third polyolefin resin layer containing the same were laminated in this order, the second PO layer contained a low-melting point polyolefin resin and had excellent gas permeability. On the other hand, Comparative Example 1, which is a single-layer film and does not contain a second polyolefin resin with a melting point of less than 95°C, does not contain a low-melting polyolefin resin and is inferior in gas permeability. Comparative Example 2, which attempted to produce a single-layer film using a second polyolefin resin with a melting point of less than 95°C, was unable to produce a single-layer film.

[0106] The disclosure of Japanese Patent Application No. 2021-190482 filed on November 24, 2021 is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated to be incorporated by reference.

Claims

1. A first polyolefin resin layer containing a first polyolefin resin having a melting point of 95°C to 200°C, a second polyolefin resin layer containing a second polyolefin resin having a melting point of less than 95°C, a third polyolefin resin layer containing a third polyolefin resin having a melting point of 95°C to 200°C, are laminated in this order, Oxygen permeability of 7500 mL / m ２ ·day·atm to 85000 mL / m ２ ·day·atm, a laminated film.

2. The laminated film according to claim 1, having a total thickness of 15 μm or more and less than 150 μm.

3. The density of the second polyolefin resin layer, measured in accordance with JIS K 7112, is 820 kg / m ３ or more and 890 kg / m ３ or less. The laminated film according to claim 1.

4. The laminated film according to claim 1, wherein the second polyolefin resin is an ethylene-α-olefin copolymer having a melting point of less than 90°C.

5. The density of the first polyolefin resin layer and the third polyolefin resin layer, each measured in accordance with JIS K 7112, is 900 kg / m ３ or more and 980 kg / m ３ or less. The laminated film according to claim 1.

6. The carbon dioxide permeability is 35,000 mL / m ２ ·day·atm to 250,000 mL / m ２ ·day·atm, the laminated film according to claim 1.

7. The laminated film according to claim 1, wherein at least one of the first polyolefin resin layer and the third polyolefin resin layer has a thickness of 5 μm to 100 μm.

8. The laminated film according to claim 1, wherein the second polyolefin resin layer has a thickness of 5 μm to 100 μm.

9. The laminated film according to claim 1, wherein the thickness ratio of the second polyolefin resin layer to the total thickness of the first polyolefin resin layer and the third polyolefin resin layer is 0.5 to 20.

0.

10. The laminated film according to claim 1, which is formed by a coextrusion inflation film forming method, a coextrusion cast film forming method, or a coextrusion lamination forming method.

11. A container heat-sealed and made of the laminated film according to any one of claims 1 to 10.

12. A cell culture container containing the laminated film according to claim 1.

13. The cell culture container according to claim 12, which contains the laminated film at the bottom.

14. The cell culture container according to claim 12, wherein the ends of the laminated film are heat-sealed to form a bag.

15. The sterility assurance level (SAL) of the medical device measured in accordance with BS EN 556-1:2001 is 10 －６ The cell culture container according to claim 14, wherein the following applies.

16. A cell culture method including a step of enclosing and sealing cells in the cell culture container according to any one of claims 12 to 15.

17. A method for manufacturing a container for cell culture, including a film forming step of coextruding a first polyolefin resin layer containing a first polyolefin resin having a melting point of 95°C to 200°C, a second polyolefin resin layer containing a second polyolefin resin having a melting point of less than 95°C, and a third polyolefin resin layer containing a third polyolefin resin having a melting point of 95°C to 200°C to obtain a laminated film.

18. The method for manufacturing a cell culture container according to claim 17, further comprising a bag-making step of heat-sealing the ends of the obtained laminated film to form a bag.

19. The method for manufacturing a cell culture container according to claim 18, further comprising a step of irradiating the obtained bag with gamma rays.

20. The method for manufacturing a cell culture container according to claim 17, wherein in the film-forming step, a laminated film is obtained using an inflation molding machine.

Images