JP6953239B2 - Plate cover film and container protection method using it - Google Patents

Description

The present invention relates to a cover film preferably used for a culture plate and a method for protecting a container using the film.

In the field of biology and biotechnology, culture plates used for culturing cells, spheroids, tissues and the like are widely used. When using a culture plate, usually, a culture such as cells and a medium are added to the wells of the culture plate, the wells are covered with an adhesive film, and then the culture plate is allowed to stand in a cell incubator. Occasionally, Patent Document 1 attempts to suppress contact between the culture solution and the pressure-sensitive adhesive in the well by not arranging the pressure-sensitive adhesive on the portion of the pressure-sensitive adhesive film corresponding to the well.

Registered Utility Model No. 3063248

However, in the above-mentioned conventional cover film for plates, it is premised that the adhesion between the plate and the film for coating is performed via an adhesive, and contact between the culture solution in the well and the adhesive is unavoidable. There was a problem, and there was a risk that a part of the adhesive eluted in the culture solution would adversely affect the culture such as cells.

The present invention reduces the amount of eluate in the medium to minimize the adverse effects on the cultured cells, and enables the cells and the like to be cultured, transported, or stored even with the cover film attached to the plate. It is an object of the present invention to provide a cover film for use and a method for protecting a container using the film.

The gist of the present invention is as follows.
[1]
It has an adhesion layer that forms an adhesion surface, and optionally, one or more base material layers laminated on a surface opposite to the adhesion surface of the adhesion layer and a release laminated on the adhesion surface of the adhesion layer. Has a mold sheet and
On the adhesion surface, the adhesion strength to polystyrene is 0.1 to 2.0 N / 25 mm .
20 g / ^{m 2} or less der Ri in the elution amount 25 ° C. from the previous SL contact surface to ethyl acetate,
The arithmetic mean roughness (Ra) of the contact surface is 0.01 to 0.70 μm.
A cover film for a plate, wherein the heat of fusion (ΔH) of the adhesion layer is 1 to 45 J / g.
[2]
The cover film for a plate according to claim 1, wherein the adhesion layer contains 50% by weight or more of a thermoplastic elastomer.
[ 3 ]
The cover film for a plate according to [1] or [2] , wherein the air permeability at 20 ° C. is 200 seconds / 100 cc or less.
[ 4 ]
The contact surface of the container containing the contents is a contact surface in which the contact surface is in close contact with the container, and the contact layer forming the contact surface is 50% by weight of a styrene-conjugated diene block copolymer and / or a hydrogenated product thereof. A method comprising protection using the plate cover film according to any one of [1] to [3], which comprises the above-mentioned elastomer.

According to the present invention, it is possible to provide a cover film for a plate capable of culturing, transporting or storing cells or the like in a favorable environment, and a method for protecting a container using the film.

(A) is a perspective view which shows the cover film for a plate of this embodiment together with a culture plate. (B) is a cross-sectional view of an example of a plate cover film of the present embodiment when cut along a surface along line I-I of (A). (C) is a cross-sectional view of another example of the plate cover film of the present embodiment when cut along a surface along line I-I of (A).

Hereinafter, embodiments for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and can be variously modified and implemented within the scope of the gist thereof.

(Cover film for plate)
The film of this embodiment is used for a culture plate, and is particularly preferably used to cover all or part of the wells of a culture plate provided with wells. In addition to the culture plate, the plate cover film of the present embodiment can also be used for containers (for example, dishes, flasks, etc.), chemical bottles, etc. used for cell culture and inspection.
FIG. 1A shows a perspective view of the plate cover film of the present embodiment together with the culture plate.

The plate cover film of the present embodiment has an adhesion strength to polystyrene of 0.1 to 2.0 N / 25 mm on at least one surface, and the amount of elution from the at least one surface to ethyl acetate. Is 20 g / m ² or less at 25 ° C.

The plate cover film of this embodiment is
It is preferable that at least 10% or more of one side surface has the adhesion strength to polystyrene in the above range and the elution amount to ethyl acetate in the above range, more preferably 30% or more, further preferably 50% or more, and the entire surface ( It is more preferable to have adhesion strength to polystyrene in the above range at 100%).

Further, the plate cover film of the present embodiment includes those having both sides of the plate cover film having the adhesion strength to polystyrene in the above range and the elution amount to ethyl acetate in the above range.

It is preferable that the plate cover film of the present embodiment is provided with a release sheet in contact with at least one of the above surfaces.
Hereinafter, a cover film for a plate having a suitable form including a release sheet will be described as an example.

The cover film for a plate of the present embodiment may be composed of one layer or may be one in which a plurality of layers are laminated.
Hereinafter, the surface of the plate cover film on the side to be attached to the culture plate will be referred to as an adhesion surface, and the layer forming such an adhesion surface will be referred to as an adhesion layer.

FIG. 1B shows a cross-sectional view of an example of the plate cover film of the present embodiment when cut along a surface along line I-I of (A).
An example film shown in FIG. 1B is composed of an adhesion layer and a release sheet laminated on the adhesion surface of the adhesion layer.

More specifically, the plate cover film of the example of the present embodiment has an adhesion strength to polystyrene of 0.1 to 2.0 N / 25 mm on the adhesion surface.
Since most of the culture plates are made of polystyrene, the plate cover film of the present embodiment needs to have adhesion strength to the polystyrene plate, sheet or film.
If the adhesion strength is less than 0.1 N / 25 mm, the plate cover film is brought into close contact with the culture plate containing the contents, and when the culture plate is transported with the cover covered, the plate cover is subjected to vibration and impact. The film is easily peeled off, and when the plate cover film surface is sideways or down, the plate cover film is easily peeled off and the contents are easily leaked.
If the adhesion strength exceeds 2.0 N / 25 mm, it becomes difficult to peel off the plate cover film attached to the culture plate, and even if it is peeled off, there is a high possibility that the contents will scatter.
Specifically, the adhesion strength to polystyrene can be measured by the method described in Examples described later.

Since the surface of the culture plate to which the plate cover film is attached is not always flat due to embossing, unevenness, etc. depending on the manufacturer, the adhesion strength is more preferably 0.2 N / 25 mm or more.
In addition, when handling the culture plate, the user often wears rubber gloves in the glove box, etc., and the adhesion strength should be 1.5 N / 25 mm or less from the viewpoint of ease of peeling. Is more preferable.

Further, in the plate cover film of the example of the present embodiment, the amount of elution from the contact surface to ethyl acetate is 20 g / m ² or less at 25 ° C.

If the elution amount of the cover film for the plate from the surface in contact with the culture plate (contact surface) to ethyl acetate ^{exceeds 20 g / m 2} at 25 ° C, the medium is easily contaminated by the eluate and the effect on cells etc. is ignored. become unable.
Here, the medium and the cell cryopreservation solution contain water, an inorganic salt, dimethylsulfoxide (DMSO), and amino acids such as glutamine and vitamins as nutrients, but these may be adjusted by a very small amount of compounding. , Externally contaminated substances may have a non-negligible effect on cells.
Ethyl acetate is usually not contained in the constituents of the medium or the cell cryopreservation solution, but is contained in the plate cover film in evaluating the amount of the substance that can be eluted from the plate cover film of the present embodiment. Ethyl acetate is used here because it is preferable to use a medium in which the components constituting the adhesive or resin to be obtained are more easily eluted, in order to determine whether or not the culture in a favorable environment is possible. It is a thing.
The amount of the plate cover film of the present embodiment eluted into ethyl acetate is preferably 10 g / m ² or less, and more preferably 5 g / m ² or less.
Specifically, the amount of elution into ethyl acetate can be measured by the method described in Examples described later.

Next, in the plate cover film of the present embodiment, the adhesion strength to polystyrene is 0.1 to 2.0 N / 25 mm on at least a part of the adhesion surface, and the amount of elution from the adhesion surface to ethyl acetate. A preferred embodiment for reducing the amount to 20 g / m ^{2 or less at 25 ° C. will be described.}

That is, in the culture plate film of the example of the present embodiment, the arithmetic mean roughness (Ra) of the surface in contact with the culture plate (contact surface) defined by JIS-B0601 is 0.01 to 0.70 μm. preferable.
Further, in the culture plate film of the example of the present embodiment, the heat of fusion (ΔH) defined by JIS-K2122 of the adhesion layer forming the surface (adhesion surface) in contact with the culture plate is 1 to 45 J / g. Is preferable.

When the Ra and / or the ΔH is in the above range, it is easy to achieve the adhesion strength to polystyrene in the above range and the elution amount to ethyl acetate in the above range in the plate cover film of the present embodiment.

The arithmetic mean roughness (Ra) of the contact surface is more preferably 0.01 to 0.2 μm.
The heat of fusion (ΔH) of the adhesion layer is more preferably 5 to 20 J / g.

The adhesion layer is preferably made of resin.

As the resin used for the adhesion layer, a resin having a heat of fusion (ΔH) of 5 to 20 J / g is preferable, and ^{a low-density polyethylene having a density of 0.91 g / cm 3} or less (very low density polyethylene, ultra) is preferable. Rhodensity polyethylene included), ethylene-propylene copolymer (random or block copolymer), ethylene-α olefin copolymer (random or block copolymer), propylene-α olefin copolymer (random or block copolymer) Polymer), ethylene-propylene-α olefin copolymer (random or block copolymer), acrylic acid-acrylic acid ester copolymer, ethylene-styrene random copolymer, polyisoprene, natural rubber, styrene-butadiene block Preferables are copolymers and their hydrogenated products, styrene-isoprene block copolymers, polyurethanes, and polysiloxanes.
Among the above resins, the thermoplastic elastomer defined by JIS K6200 is preferable. Specifically, the rubber phase of the blend consists of a blend of polyolefin and ordinary rubber, and the rubber phase of the blend consists of an olefin-based thermoplastic elastomer (TPO) with no or few cross-linking points; styrene and a specific diene. It is a copolymer of at least 3 blocks, and the two blocks (hard blocks) at both ends are polystyrene, and the internal block (one or more soft blocks) is a styrene-based heat composed of a thermoplastic or a thermoplastic hydride. Thermoplastic elastomer (TPS); hard blocks are made of urethane bonds, soft blocks are made of ether, ester, or carbonate bonds, or a mixture thereof, and are composed of block polymers consisting of alternating hard segments and soft segments. Urethane-based thermoplastic elastomer (TPU) is more preferable. In particular, TPS is more preferable because it has excellent adhesion to polystyrene and other plastic containers.
These resins may be used alone or in a blend of two or more. When blended, the content of the resin in the adhesion layer is preferably 50% by weight or more, more preferably 75% by weight or more. The heat of fusion (ΔH) of the resin in the case of blending refers to a value in the blended product.

The melt flow rate (MFR) (condition of 230 ° C., 2.12N) of the resin is preferably 1 to 100 g / 10 min, and more preferably 2 to 50 g / 10 min. The MFR is a value of the blend or the mixture in the case of a blend of two or more kinds of resins or a mixture of additives such as an antistatic agent, a tackifier, and a flow conditioner.

The thickness of the adhesion layer is preferably 1 μm to 1 mm, more preferably 3 μm to 200 μm. Since the thickness of the adhesion layer affects the adhesion with the plate, it is more preferably 30 μm to 150 μm.

The release sheet is a polyolefin resin such as polypropylene (PP), high-density polyethylene (HDPE), poly (4-methyl-1-pentene), cyclic polyolefin (COC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT). ), Polyester methylene terephthalate (PTT), polycyclohexanedimethylene terephthalate (PCT) and other polyester resins, polystyrene (PS), polyoxymethylene (POM), polyamide (PA) and other resins, paper, wood, non-woven fabrics, Sheets or films such as woven fabrics; metals or foils thereof; those subjected to silicone coating, fluorine coating, roughening treatment, etc. are mentioned, and are made of polyester resin or polystyrene (PS) from the viewpoint of handleability. Sheet or film is preferred.

The arithmetic mean roughness (Ra) defined by JIS-B0601 of the surface of the release sheet in contact with the adhesive layer of the plate cover film is preferably 0.70 μm or less.
The adhesive layer of the film is a resin or resin composition called an elastomer and is flexible. Therefore, depending on the conditions such as temperature, humidity, and time when transporting or storing the film, a release sheet may be formed on the adhesive surface of the film. The unevenness of the surface in contact with the adhesion layer may be transferred. If the Ra of the surface of the release sheet in contact with the adhesion layer is larger than 0.70 μm, the Ra of the surface (adhesion surface) of the cover film for the plate in contact with the culture plate may deviate from the preferable range.

The plate cover film of the present embodiment preferably has an air permeability of 200 seconds / 100 cc or less at 20 ° C. as measured by a Garley type densometer in accordance with JIS-P8117 with the release sheet removed. ..
If the air permeability exceeds 200 seconds / 100 cc, there is a concern that the oxygen concentration in the well will decrease and the cells will die when the cells living at room temperature are cultured, transported and stored.
For a microplate having a larger number of wells than 96 wells, a film having more excellent gas permeability is more preferable, and the air permeability is 100 seconds / 100 cc or less, more preferably 60 seconds / 100 cc or less. Oxygen permeability of the air permeability of about 60 sec / 100 cc film corresponds to approximately ^{10 7 cc / m 2 · day} · atm.
The air permeability is also preferably 0.1 second / 100 cc or more.
When the air permeability is less than 0.1 seconds / 100 cc, the air permeability is good, and depending on the conditions such as temperature, humidity, and storage period, the components of the medium volatilize from the well through the cover film for the plate, and the cells die. There is a concern that it will end up. The air permeability is more preferably 10 seconds / 100 cc or more.

In the present embodiment, in order to provide the plate cover film with the above-mentioned air permeability, (i) a highly breathable material such as polyurethane or polysiloxane is used for the adhesion layer, the base material layer, etc. (ii). (Iii) The cover film for a plate is perforated by using a so-called microporous film, which is made to have air permeability by removing them from a layer prepared by dispersing no equipment or a solvent or the like. However, perforated processing is preferable from the viewpoint of cost and internal visibility.

As described above, the plate cover film of the present embodiment may be provided with a plurality of holes by perforation processing.
It is preferable that the holes are uniformly formed in the plane of the plate cover film. The shape of the hole is not particularly limited, and may be a circle, a square, an ellipse, a slit, or the like.
The diameter of the holes is 0.1 to 500 μm, and the distance between the holes (hereinafter referred to as “hole pitch”) is 0.1 to 6.5 mm. It is preferable to achieve it. Further, the diameter of the hole is more preferably 0.5 to 100 μm, further preferably 1 to 30 μm. The hole pitch is more preferably 0.3 to 4 mm, still more preferably 0.5 to 3 mm, assuming a microplate having a larger number of wells than 96 wells.
The diameter of the hole is the diameter of the inscribed circle of the opening.
The diameter of the pores and the pitch of the pores may be appropriately adjusted so as to be a suitable environment for the cells to be cultured, and at least one per well in a 96-well culture plate in which wells are provided at equal intervals in the vertical and horizontal directions. When providing holes, for example, half (for example, 4.6 mm) of the distance D1 (for example, 9.2 mm) (see FIG. 1) between the centers of two adjacent wells is used as the hole pitch and perforated. Also, perforation is performed with a hole pitch of half (for example, 6.5 mm) of the distance D2 (for example, 13 mm) (see FIG. 1) between the centers of two wells that are offset by one row in the vertical and horizontal directions. May be good.
For perforated processing of such small holes, as disclosed in Japanese Patent Application Laid-Open No. 2014-237810, perforated processing is performed between two rolls provided with spiral protrusion blades on the roll surface. A method capable of providing holes at a minute and uniform pitch through the desired sheet is preferably applied.

The plate cover film of the present embodiment may be sterilized by EOG gas sterilization, ultraviolet sterilization, electron beam sterilization, γ-ray sterilization, or the like.

FIG. 1C shows a cross-sectional view of another example of the plate cover film of the present embodiment when cut along a surface along line I-I of (A).
Another example of the film shown in FIG. 1C is a release sheet laminated on the adhesion layer, a release sheet laminated on the adhesion surface of the adhesion layer, and a base material layer laminated on the surface opposite to the adhesion surface of the adhesion layer. It consists of.

The adhesion layer and release sheet in the plate cover film of another example of the present embodiment may be the same as the adhesion layer and release sheet of the plate cover film of the example of the present embodiment described above.

Examples of the resin used for the base material layer include polyester resins such as polypropylene (PP), high-density polyethylene (HDPE), poly (4-methyl-1-pentene), and cyclic polyolefin (COC), polyethylene terephthalate (PET), and the like. Polyester resins such as polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polycyclohexanedimethylene terephthalate (PCT), polystyrene (PS), polyoxymethylene (POM), polyamide (PA), polyurethane, polysiloxane Resins such as, paper, wood, non-woven fabrics, sheets or films such as woven fabrics; metals or foils thereof; etc. Or a sheet or film made of polystyrene (PS) is preferable.

The thickness of the base material layer is preferably 1 μm to 1 mm, more preferably 5 μm to 0.5 mm.

The plate cover film of the present embodiment may have other layers in addition to the above-mentioned adhesion layer, base material layer and release sheet.

The culture plate used in the present embodiment may be a culture plate provided with one or more (for example, 6, 24, 96, 384, etc.) wells on the upper surface thereof.
In the culture plate, it is preferable that the portion of the upper surface other than the well opening is located on the same plane from the viewpoint of enhancing the adhesiveness between the culture plate and the film of the present embodiment.

The plan view shape of the plate cover film of the present embodiment is not particularly limited, and examples thereof include a circle, an ellipse, and a rectangle, and may be usually a rectangle. The rectangle may have rounded corners.

The material for forming at least the upper surface and the well surface of the culture plate is preferably a resin composition, and preferably contains a resin and, if necessary, other additives.
Examples of the resin include polystyrene, polyethylene, polypropylene, polyethylene terephthalate (PET), polybutene, polycarbonate, poly (4-methyl-1-pentene) and the like.

(How to protect the container containing the contents with a film)
The plate cover film of the present embodiment is a contact surface in which at least one side of the container containing the contents is in close contact with the container, and the contact layer forming the contact surface is a styrene-conjugated diene block copolymer weight. It can be used in a method characterized by protection using a plate cover film of the present embodiment made of an elastomer containing 50% by weight or more of the coalesced and / or hydrogenated product thereof.

Examples of the container of the present embodiment include the above-mentioned culture plate, dish, flask and the like in which the plate cover film of the present embodiment can be preferably used. In particular, the method of this embodiment is preferably used for a 96-well culture plate or a porous plate such as a microplate having a larger number of wells than the 96-well.
Examples of the contents of the container of the present embodiment include a culture solution, a cell cryopreservation solution, cells, spheroids, tissues and the like.

The elastomer constituting the adhesion layer of the plate cover film of the present embodiment contains 50% by weight or more of the styrene-conjugated diene block copolymer and / or its hydrogenated product, and is preferably 70% by weight from the viewpoint of adhesion. Above, more preferably 75% by weight or more.

The plate cover film of the present embodiment has an adhesion strength to polystyrene of 0.1 to 2.0 N / 25 mm and an elution amount to ethyl acetate ^{of 20 g / m 2 or less at 25 ° C. in 10% or more of the adhesion surface.} 30% or more is more preferable, 50% or more is further preferable, and it is further preferable to have adhesion strength to polystyrene in the above range on the entire surface (100%).

Further, the plate cover film of the present embodiment also includes a film having both sides of the film having adhesion strength to polystyrene in the above range and elution amount to ethyl acetate in the above range.

The cover film for a plate of the present embodiment may be composed of one layer or may be one in which a plurality of layers are laminated.

As a method of protecting the container of the present embodiment, for example, a hand roller or the like can be used to attach a close contact surface of the film to the container so as to cover the opening of the container containing the contents. ..

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

The materials used in the examples and comparative examples are as follows.

(1) Resin / elastomer for adhesive layer 1: Zelas (registered trademark) MC719 manufactured by Mitsubishi Chemical Corporation
MFR (230 ° C; 21.2N) = 3g / 10min, density = 0.89g / cm ³ , melting point = 157 ° C, ΔH = 15J / g
-Elastomer 2: Zelas 7055 manufactured by Mitsubishi Chemical Corporation
MFR (230 ° C; 21.2N) = 7g / 10min, density = 0.89g / cm ³ , melting point = 164 ° C, ΔH = 61J / g
-Elastomer 3: Tough Tech (registered trademark) H1221W manufactured by Asahi Kasei Corporation
MFR (230 ° C; 21.2N) = 4.5g / 10min, density = 0.89g / cm ³ , melting point = 116 ° C, ΔH = 0.5J / g
-Elastomer 4: Tough Tech L521W manufactured by Asahi Kasei Corporation
MFR (230 ° C; 21.2N) = 15g / 10min, density = 0.89g / cm ³ , melting point = 103 ° C, ΔH = 0.8J / g
-PP: Wintech (registered trademark) WFX4M manufactured by Japan Polypropylene Corporation
MFR (230 ° C; 21.2N) = 7g / 10min, density = 0.9g / cm ³ , melting point = 125 ° C, ΔH = 72J / g
(2) Film for base material layer, PET1
Polyethylene terephthalate film manufactured by Toray Industries, Inc. with a thickness of 50 μm and corona treatment on the bonded surface: Lumirror (registered trademark) T60
(3) Release sheet / release sheet 1
Polyethylene terephthalate film manufactured by Toray Film Processing Co., Ltd. with a thickness of 75 μm and silicone processing on the bonded surface; Therapy (registered trademark) MFA. Ra measured by the method shown below is 0.019 μm.
・ Release sheet 2
Toray Industries, Inc. Polyethylene terephthalate film with a matte finish and a thickness of 75 μm; Lumimat (registered trademark) # 300 tress. Ra measured by the method shown below is 0.75 μm.
(4) Adhesive SK Dyne (registered trademark) E-4105 manufactured by Soken Chemical Co., Ltd., which is an emulsion-type adhesive containing acrylic acid ester resin as the main component.
(5) Culture plate-Prime Surface (registered trademark) 96U MS-9096U (96-well plate) manufactured by Sumitomo Bakelite Co., Ltd.

The analysis method and evaluation method used in Examples and Comparative Examples are as follows.

(A) Adhesion strength to polystyrene With respect to the culture plate films prepared in Examples and Comparative Examples described later, the adhesion strength (N / 25 mm) to polystyrene was measured under the following conditions.
-Polystyrene: OPS film GMCO manufactured by Asahi Kasei Corporation with a thickness of 50 μm
-Measuring machine: Tensilon universal tester RTC-1210A manufactured by Orientec Co., Ltd.
-Measurement environment: 23 ° C, 50% RH
-Test piece size: 25 mm width x 100 mm length-Measurement conditions: 90 ° peeling (peeling speed 50 mm / min)
-Pretreatment: After wiping the surface of the polystyrene film with clean gauze, the surfaces to which the cover film for the plate was attached were overlapped, and the film was attached under a pressure of 0.1 MPa, and then the humidity was adjusted for 30 minutes before use.

^{(B) Elution amount to ethyl acetate The elution amount (g / m 2} ) from the contact surface to ethyl acetate was measured under the following conditions for the culture plate films prepared in Examples and Comparative Examples described later.
After measuring and recording the weight of a glass petri dish manufactured by Tokyo Glass Instruments Co., Ltd. with an inner diameter of 80 mm using an electronic balance HM-200 manufactured by A & D Co., Ltd., ethyl acetate (purity 99.9%) manufactured by Wako Pure Chemical Industries, Ltd. 40 mL Was put in, covered with a cover film for a plate, and further covered with a glass petri dish of the same diameter to fix it. Then, at 25 ° C., shake with a shaker MK161 manufactured by Yamato Scientific Co., Ltd. at a speed of 60 rpm for 60 minutes, then peel off the cover film for the lid and the plate, and remove the petri dish containing the liquid from the headwind constant temperature and constant temperature manufactured by Yamato Scientific Co., Ltd. It was dried in a vessel DK-400 at 80 ° C. for 60 minutes. Next, the weight of the glass petri dish taken out from the incubator is measured with the electronic balance, the weight difference from the pre-measured glass petri dish alone is obtained, and the obtained value is converted into square meters from the diameter of the glass petri dish and eluted. I asked for the amount.

(C) Arithmetic Mean Roughness (Ra)
The arithmetic average roughness (Ra) (μm) of the contact surface was measured under the following conditions in accordance with JIS-B0601 for the culture plate films prepared in Examples and Comparative Examples described later.
・ Measuring machine: ACCRETECH SURFCOM 1400D-3DF manufactured by Tokyo Seimitsu Co., Ltd.
-Measurement environment: 20 ° C ± 1 ° C, 60% RH
・ Needle: Tip 2 μm, θ = 60 °

(D) Heat of fusion (ΔH)
For the culture plate films prepared in Examples and Comparative Examples described later, the heat of fusion (ΔH) (J / g) of the adhesion layer was measured under the following conditions in accordance with JIS-K2122.
-Test piece: A sample of 2.5 mg was collected from the adhesion layer using a cutter or the like and used for measurement.
-Measuring device: Differential scanning calorimetry DSCQ-100 manufactured by TA Instruments Japan Co., Ltd.
-Measurement conditions: The temperature is raised from -60 ° C to 10 ° C / min, held at 180 ° C for 2 minutes, cooled to -60 ° C at 10 ° C / min, and then raised again to 180 ° C at 10 ° C / min. Then, the amount of heat of fusion at that time was calculated.

(E) Leakage resistance The leak resistance of the culture plate films prepared in Examples and Comparative Examples described later was evaluated under the following conditions.
-Evaluation method: Put 100 μL of purified water in each well of the culture plate, attach the cover film for the plate at a pressure of 0.1 MPa using a hand roller, hold the plate horizontally, and shake it by hand to leak liquid. The presence or absence was confirmed with the naked eye (evaluation 1). The sample without liquid leakage was further stored at -80 ° C for 5 days using a freeze ultra-low temperature tank CLN-32UW manufactured by Nippon Freezer Co., Ltd., and the peeling state was visually confirmed (evaluation 2).
・ Evaluation criteria ◎: No peeling in evaluation 2 ○: No liquid leakage occurred in evaluation 1 Δ: Part of the cover film for the plate was peeled off in evaluation 1 and liquid leakage occurred ×: For the plate Cover film peels off, causing liquid leakage

(F) Ease of peeling The culture plate films prepared in Examples and Comparative Examples described later were evaluated for ease of peeling under the following conditions.
-Evaluation method: 100 μL of purified water is put into each well of the culture plate, a plate cover film is attached at a pressure of 0.1 MPa using a hand roller, and then nitrile ultra-thin gloves manufactured by Kawanishi Kogyo Co., Ltd. are attached. The cover film was peeled off with, and the peeling condition was confirmed.
·Evaluation criteria:
◯: The cover film for the plate could be peeled off from the plate without the liquid splashing. Δ: The liquid was scattered due to the force applied though it was peeled off.

(G) Elution to medium The elution to medium was evaluated under the following conditions for the culture plate films prepared in Examples and Comparative Examples described later.
-Medium: FM-1 cryopreservation medium manufactured by Far East Pharmaceutical Co., Ltd.
Composition (in 1L)
Eagle MEM medium: 9.4 g
Methyl cellulose: 2.0 g
Dimethyl sulfoxide: 200 mL
L-Glutamine: 0.3g
Sodium hydrogen carbonate: 1.0 g
Pure water: 800 mL
-Evaluation method: After putting 100 μL of the culture solution into each well of the culture plate, a plate cover film was attached at a pressure of 0.1 MPa using a hand roller. Then, the culture solution was shaken so as to adhere to the surface on which the cover film for the plate was attached, and the mixture was allowed to stand at 25 ° C. for 7 days. After the lapse of the period, a sample injection needle was inserted with the plate cover film attached, and the components of the culture solution in the wells were analyzed by a liquid chromatograph mass spectrometer LCMS-8060 manufactured by Shimadzu Corporation.
-Evaluation criteria ⊚: Total amount of eluate is less than 10 μg / 100 μL ○: Total amount of eluate is 10 μg / 100 μL or more and less than 50 μg / 100 μL Δ: Total amount of eluate is 50 μg / 100 μL or more and less than 100 μg / 100 μL ×: Eluate Total amount of 100 μg / 100 μL or more

(H) Hole Diameter and Hole Pitch For the perforated culture plate film produced in Examples and Comparative Examples described later, the hole diameter (μm) and hole pitch (mm) are determined by KEYENCE Digital. The measurement was performed using a microscope VHX-1000 and its measuring software. The measurement magnification was appropriately selected according to the diameter of the holes and the pitch of the holes.

(I) Air permeability With respect to the culture plate films prepared in Examples and Comparative Examples described later, the air permeability (seconds / 100 cc) was measured at 20 ° C. using a densometer manufactured by Yasuda Seiki Seisakusho in accordance with JIS-P8117. bottom.

(J) Cell mass size and cell viability Cell culture was performed using the culture plate films prepared in Examples and Comparative Examples described later, and the cell mass size and cell viability were measured with a Keyence digital microscope VHX-1000. Cell viability was calculated.

Other specifications are as shown in Table 1.

(Test Example A)
Elastomer 1 is thermally melted using an extruder having a cylinder diameter (D) of 90 mm and L / D = 35, and extruded from a T-die having a width of 1000 mm so that the resin temperature is 280 ° C. and the thickness is 80 μm to form an adhesion layer. Obtained. A release sheet 1 was laminated between a casting roll having a surface temperature of 15 ° C. and a rubber backup roll on one side of the adhesion layer, and the laminated body was taken up.
Next, a base material layer was bonded to the surface of the adhesive layer of the laminated body using a polyurethane adhesive, and this was cut into 79 mm × 120 mm (Example 1).
On the other hand, after drying, the adhesive was applied to one side of the base material layer with a ^{bar coater so that the coating amount was 22 g / m 2} , dried at 85 ° C. for 3 minutes, and left at room temperature for 5 minutes. Then, the release sheet 1 was superposed on the other surface of the base material layer, and this was cut into 79 mm × 120 mm (Comparative Example 1).
Table 1 summarizes the evaluation results of Example 1 which is the cover film for a plate of the present invention and Comparative Example 1 which uses an adhesive imitating a conventional product.

表１において、実施例１は耐漏れ性、剥がし易さ、低溶出性全てにおいて優れていた。一方、比較例１は粘着剤（ΔＨ≒０Ｊ／ｇ）が溶出して低溶出性が著しく劣っていたほか、実施例１に比べ、低温での耐漏れ性と剥がし易さで劣っていた。

In Table 1, Example 1 was excellent in all of leakage resistance, ease of peeling, and low elution. On the other hand, in Comparative Example 1, the pressure-sensitive adhesive (ΔH≈0J / g) was eluted and the low elution property was remarkably inferior, and in comparison with Example 1, the leakage resistance at low temperature and the ease of peeling were inferior.

(Test Example B)
Example 2 uses a composition in which PP and elastomer 3 are melt-blended at a weight ratio of 50:50 as an adhesion layer by a twin-screw extruder, and Example 3 uses PP and elastomer 4 as an adhesion layer in a weight ratio. The same operation as in Example 1 of Test Example A was repeated except that the composition melt-blended by a twin-screw extruder was used at 25:75, and the elastomer 2 was used as the adhesion layer in Comparative Example 2.
Further, the same operation as in Example 3 was repeated except that the release sheet 1 was replaced with the release sheet 2 (Comparative Example 3).
The evaluation results of Examples 2 and 3 and Comparative Examples 2 and 3 are summarized in Table 2.

The evaluation was good for Examples 2 and 3 which are the cover films for plates of the present invention.
On the other hand, in Comparative Example 2, ΔH was as high as 61 J / g, the adhesion to polystyrene was weak, and therefore the leakage resistance was inferior.
Further, in Comparative Example 3, Ra was as large as 0.75 μm, and the leakage resistance was inferior as in Comparative Example 2.

(Test Example C)
With reference to Japanese Patent Application Laid-Open No. 2014-237810, in Test Example A, a spiral blade having a blade width of 10 μm and a pitch of 2 mm was engraved on a metal roll having a roll diameter of 55 mm and a length of 55 mm. Through the plate film of Example 1, holes having a diameter of 10 μm and a pitch of 2 mm were provided (Example 4). The air permeability of the plate cover film was 200 seconds / 100 cc.
The plate cover film of Comparative Example 1 of Test Example A and the lid (conventional example) sold as a set with the culture plate were also used in this Test Example.
As a medium, DMEM manufactured by Sigma-Aldrich Japan Co., Ltd. supplemented with 10% fetal bovine serum (FBS) manufactured by Cosmo Bio Co., Ltd. and an antibiotic was used, and human line fibroblasts were seeded on a plurality of culture plates. It was left at room temperature for 2 days.
The prepared culture plate during cell culture was divided into three groups, one of which was covered with the plate cover film of Example 4, and the other group was covered with the plate cover film of Comparative Example 1. The culture plate was covered. The above two groups were placed in a transport container adjusted to room temperature and left for 24 hours. The remaining 1 group was covered with a conventional lid and _{cell culture was performed in a CO 2} incubator for 24 hours (control conditions).
When the cell clusters (spheroids) of these three groups were observed with the above microscope, the spheroid diameters of those covered with the conventional lid and those covered with the plate cover film of Example 4 were similarly increased. Although it was 700 μm, the spheroid diameter of the plate cover film of Comparative Example 1 covered with the cover film was 750 μm. Compared with the conventional example and the fourth example, the cohesive force of the spheroid was weaker in the comparative example 1.
As for the cell viability, 97.6% of the cells were covered with the lid of the conventional example, whereas 97.5% of the cells were covered with the cover film for the plate of Example 4. .. In Example 4, the environment seemed to be a little difficult for cells to breathe, but the survival rate was comparable to that of the conventional example. In addition, in the case of the one covered with the plate cover film of Example 4, an organ could be prepared without any problem even if the spheroid was taken out from the culture plate after being stored for another day.

From the above, the cover film for a plate of the present invention can maintain the culture environment in the well even with the cover film attached to the plate, and can be used in a series of steps from culture to transportation and storage. I found out.

According to the present invention, by reducing the amount of eluate in the medium, the adverse effect on the cultured cells can be reduced as much as possible, and the cells and the like can be cultured, transported or stored even with the cover film attached to the plate. Become. Furthermore, according to the present invention, by increasing the air permeability of the film, cells and the like can be cultured in a better environment.
The plate cover film of the present invention is suitably used to cover a culture plate in which cells, spheroids, tissues, organs and the like are cultured, transported or stored in a well.
The plate cover film of the present invention can be used not only for culture plates but also for dishes (petri dishes) and flasks.

Claims (4)

It has an adhesion layer that forms an adhesion surface, and optionally, one or more base material layers laminated on a surface opposite to the adhesion surface of the adhesion layer and a release laminated on the adhesion surface of the adhesion layer. Has a mold sheet and
The adhesion strength to polystyrene on the adhesion surface is 0.1 to 2.0 N / 25 mm .
20 g / ^{m 2} or less der Ri in the elution amount 25 ° C. from the previous SL contact surface to ethyl acetate,
The arithmetic mean roughness (Ra) of the contact surface is 0.01 to 0.70 μm.
A cover film for a plate, wherein the heat of fusion (ΔH) of the adhesion layer is 1 to 45 J / g. The cover film for a plate according to claim 1, wherein the adhesion layer contains 50% by weight or more of a thermoplastic elastomer. The cover film for a plate according to claim 1 or 2, wherein the air permeability at 20 ° C. is 200 seconds / 100 cc or less. The contact surface of the container containing the contents is a contact surface in which the contact surface is in close contact with the container, and the contact layer forming the contact surface is 50% by weight of a styrene-conjugated diene block copolymer and / or a hydrogenated product thereof. A method according to any one of claims 1 to 3, wherein the plate cover film comprising the above-mentioned elastomer is used for protection.

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