JP2023090107A - Sterilization bag - Google Patents

Abstract

To provide a sterilization bag which has sufficient air permeability to a medium showing a sterilization action, and can perform effective sterilization treatment.SOLUTION: A sterilization bag is composed of a bag body formed by mutually bonding a transparent resin film 1 and a sheet 3 composed of an air permeable material on at least one side along each peripheral edge part 4, wherein the transparent resin film 1 has an uneven structure on a surface on a side facing the sheet 3. A size of a projection of the uneven structure is 20 nm or more and 50 μm or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a sterilization bag used for sterilizing medical equipment, sanitary products, and the like.

BACKGROUND ART In the sterilization of medical devices, a sterilization bag is generally used that can prevent reattachment of bacteria to the sterilization target by enclosing the sterilization target in the bag and performing sterilization. The sterilization bag has, at least in part, a member that is permeable to gases such as hydrogen peroxide gas, ethylene oxide gas (EOG), and water vapor, but impermeable to bacteria. Although there are sterilization bags made entirely of breathable and opaque materials such as non-woven fabrics, sterilization bags that use a transparent resin film for at least a portion thereof are widely used from the viewpoint that the contents can be seen. ing.

In such a sterilization bag, the transparent resin film and the contents of the sterilization bag sometimes come into close contact with each other due to depressurization or pressurization in the sterilization process. The transparent resin film is generally impermeable (permeability to various gases, which are media for the sterilization effect, is extremely low), and the part of the object to be sterilized in close contact with the transparent resin film exerts the sterilization effect. There is a problem that sterilization failure occurs without being exposed to various gases that are media.

In response to such problems, Patent Document 1 describes a sterilization bag made of a heat-resistant plastic film having a thermoplastic resin layer with an uneven surface, and a non-woven fabric disposed on all or part of the peripheral seal portion. there is

Japanese Patent Publication No. 60-9816

However, in the sterilization bag of Patent Literature 1, the nonwoven fabric portion disposed in the peripheral seal portion is the only portion where various gases, which are the medium for the sterilization effect, can enter the bag body. In addition, since the peripheral edge seal portion is generally formed with a width of at least several millimeters or more, various gases must pass through the nonwoven fabric to enter the bag body at least several millimeters or more. Therefore, there is a problem that air permeability is remarkably poor and effective sterilization cannot be performed.

Furthermore, as described above, since only the nonwoven fabric portion disposed in the peripheral seal portion has an air-permeable structure, depending on the sealing method and the width and thickness of the sealed portion, the air holes of the nonwoven fabric may be crushed. Furthermore, there was also a concern that the air permeability would be lowered.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sterilization bag which has sufficient permeability to a medium for sterilization and which can be effectively sterilized.

The present invention provides a sterilization bag configured as follows. That is, the sterilization bag of the present invention is a sterilization bag comprising a bag body in which a transparent resin film and a sheet made of an air-permeable material are attached to each other along at least one side along the peripheral edge of each of the transparent resin films. The resin film has an uneven structure on the surface facing the sheet.

According to the present invention, since one surface of the bag body is made of a sheet made of an air-permeable material, the air-permeability is sufficient for a medium that exerts a sterilizing action, and effective sterilization can be performed. can be done. In addition, since the inner surface of the transparent resin film constituting the other surface of the bag, that is, the surface facing the sheet has an uneven structure, it prevents the contained objects to be sterilized from coming into close contact with each other, enabling effective sterilization. It can be carried out.

1 is a schematic cross-sectional view of a sterilization bag according to a first embodiment of the present invention; FIG. 1 is a schematic perspective view of a sterilization bag according to a first embodiment of the present invention; FIG. The schematic perspective view of the uneven structure formed in the transparent resin sheet which concerns on 3rd Embodiment of this invention. The schematic sectional drawing of the sterilization bag which concerns on 4th Embodiment of this invention.

Embodiments of the present invention will be described in detail below with reference to the drawings. It should be noted that the embodiments of the present invention described below are examples for explaining various concepts such as a broader concept, a middle concept, and a lower concept of the present invention. Therefore, the technical scope of the present invention is not limited to the following embodiments.

<First Embodiment>
FIG. 1 is a schematic cross-sectional view according to a first embodiment of the invention. The sterilization bag 10 is composed of a bag body obtained by pasting together a transparent resin film 1 and a sheet (hereinafter referred to as a breathable sheet) 3 made of a breathable material at the peripheral portion 4 . The surface of the transparent resin film 1 facing the air-permeable sheet 3 is provided with an irregularity-forming layer 2 having a periodic irregularity structure.

In the concave-convex structure formed in the concave-convex forming layer 2, the size of the convex portion 2b is preferably 20 nm or more and 50 μm or less. Here, the size of the convex portion 2b refers to the length of the cross section of the convex portion on the surface of the portion of the concave-convex forming layer 2 that forms a continuous layer. This surface can also be expressed as a surface in which the lowest portions of the concave portions 2a between the convex portions 2b are connected. As will be described later, the shape of the convex portion 2b includes various shapes, but when the cross section is circular, it is represented by its diameter. It can also be considered as the diameter of the circumscribed circle of this shape, if the cross-section is polygonal or of some other shape.

In this embodiment, the concave-convex structure is a periodic structure, but the convex portions 2b may be formed randomly. In addition, between the convex portions adjacent to each other, there may be a portion parallel to the surface of the continuous layer described above, or the convex portions 2b adjacent to each other without such parallel portions may be provided. may be closely arranged.

(transparent resin film)
The transparent resin film 1 shown in FIG. 1 has the function of blocking bacteria. This transparent resin film 1 may have a single-layer structure or a multi-layer structure. For example, the transparent resin film 1 of this embodiment has a two-layer structure of an upper layer positioned on the side exposed to the outside air and a lower layer positioned on the inner surface of the bag.

Separate functions may be imparted to the upper layer and the lower layer of the transparent resin film 1, respectively. For example, barrier properties, heat resistance, and rigidity can be imparted to the upper layer, and flexibility and thermoplasticity at relatively low temperatures can be imparted to the lower layer. By imparting separate functions in this manner, the sterilization bag can be made more effective in blocking bacteria from the outside air after sterilization, and can withstand high-temperature treatments such as high-pressure steam sterilization. In addition, it is possible to prevent accidents such as pinholes, scratches, and explosion during the sterilization process or during handling. Furthermore, by using a thermoplastic resin for the lower layer, it is possible to easily seal the air-permeable sheet 3 facing each other by heat sealing (thermocompression bonding).

Suitable examples of the material constituting such an upper layer include biaxially oriented polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) films, and polyamide (PA) films typified by nylon. These films make it possible to form an upper layer having barrier properties, heat resistance, and rigidity as described above.

In addition, these films have a high total light transmittance in the visible light wavelength range and a small haze value, so they exhibit excellent transparency. As a specific example, T60 Lumirror #75 (Toray Industries, Inc.) is a 75 μm thick PET film exhibiting a total light transmittance (550 nm) of 89.0% and a haze value of 1.1%. . By using such a film as the upper layer of the transparent resin film 1, inclusions such as objects to be sterilized can be easily visually recognized. Furthermore, these films are widely used for various purposes, and can be mass-produced at low cost by roll-to-roll method, etc., so that the cost of sterilization bags can be reduced. The thickness of this upper layer is preferably in the range of 20 to 100 μm, considering the balance between the bacteria-blocking property and strength retention and ease of handling.

Suitable examples of the material forming the lower layer of the transparent resin film 1 include a low-density polyethylene (LDPE) film and an unstretched polypropylene (PP) film. These films can be heat-sealed at a temperature of about 100 to 120.degree. Therefore, in combination with the upper layer made of the above constituent materials, heat sealing with the breathable sheet 3 in contact with the lower layer side can be easily performed while preventing fusion with the heat sealer in contact with the upper layer side.

Moreover, in combination with the upper layer composed of the above constituent materials, the transparent resin film 1 can be given appropriate flexibility and can be easily handled. From this point of view, the thickness of the lower layer is preferably in the range of 5 to 30 μm. LDPE film and unstretched PP film are inferior in transparency to biaxially stretched PET film and nylon film, and if the film is too thick, visibility inside the sterilization bag may be impaired.

The preferred thickness of the transparent resin film 1 in this embodiment is 25 to 130 μm in total for the upper layer and the lower layer, but a thicker transparent resin film may be used depending on the application. According to the packaging terminology standard Z0108 of JIS (Japanese Industrial Standards), a film having a thickness of less than 250 μm is called a film, and a film having a thickness of 250 μm or more is called a sheet. shall be called. Further, in this embodiment, a two-layer structure is used, but a single-layer structure may be used.

In addition, as the transparent resin film 1, a film manufactured from a biomass-derived raw material such as a plant resource represented by polylactic acid (PLA) can also be used without any problem. PLA films and sheets do not use petroleum as a raw material, are carbon-neutral, and are excellent in biodegradability. Therefore, by using them, environmentally friendly sterilization bags can be manufactured. Here, carbon neutral means that the amount of carbon dioxide absorbed by plants, which are raw materials, is the same as the amount of carbon dioxide that is finally emitted into the atmosphere by combustion and decomposition, so the amount of carbon dioxide on the earth is increased. never say that. In recent years, films and sheets using PE using biomass as a raw material have also been actively developed, and there is no problem in using these.

The method of manufacturing the transparent resin film 1 composed of two layers, the upper layer and the lower layer, of this embodiment is not particularly limited, and may be appropriately selected from known techniques. For example, the upper layer is used as the base material, and the lower layer is formed on the upper layer by a dry lamination method in which the upper layer is attached by thermocompression via an adhesive, or a wet film formation method such as a casting method, a gravure coating method, a die coating method, or a screen printing method. method.

Also, the surface of the transparent resin film 1 may be coated with various coatings for the purpose of imparting functions such as transparency improvement, water repellency or hydrophilicity, strength improvement, etc., without any problem. As an example, a single-layer thin film of a low refractive material (eg, MgF2), or a multi-layered film in which a low refractive material (eg, SiO2) and a high refractive material (eg, TiO2) are alternately laminated is used as the transparent resin film 1. It may be formed on the surface of the side exposed to the outside air. Such coatings can further improve visibility within the sterilization bag by reducing reflectance. The above single-layer thin film or multilayer film can be formed by a vacuum deposition method or the like.

(Unevenness formation layer)
The ruggedness-forming layer 2 is arranged on the surface of the transparent resin film 1 facing the air-permeable sheet 3, and has a fine ruggedness structure formed on its surface. The concave portions 2a of the concave-convex structure serve as passages or holding spaces for various gases, which are media for sterilization, entering from the breathable sheet 3 into the sterilization bag 10 during the sterilization process. As a result, the objects to be sterilized contained in the sterilization bag 10 can be prevented from being insufficiently exposed to the above various gases.

The concave-convex forming layer 2 may be formed as a part of the transparent resin film 1, or may be formed by laminating the transparent resin film 1 using a constituent material different from that of the transparent resin film 1. Also good. For example, in the present embodiment, it is formed on the surface facing the air-permeable sheet 3 as part of the lower layer of the transparent resin film 1 consisting of two layers, an upper layer and a lower layer.

In this embodiment, the concave-convex structure is arranged on the entire surface except for the peripheral edge portions 4 where the transparent resin film 1 and the air-permeable sheet 3 are bonded together. The size of the convex portion 2b is preferably 20 nm or more and 50 μm or less. As a result, it is possible to provide an appropriate space between the transparent resin film 1 and the object to be sterilized contained in the bag, through the concave-convex structure, into which various gases having a sterilizing effect can enter or be held.

If the size of the convex portion 2b is 20 nm or less, it becomes difficult for the gas to enter the concave portion 2a. In addition, since the period of the concave-convex structure becomes very short, it becomes macroscopically flat, and the transparent resin film 1 and the inclusions are more likely to adhere to each other. become difficult.

On the other hand, when the size of the protrusions 2b is 50 μm or more, the contact area between the transparent resin film 1 and the inclusions increases, the penetration in the direction parallel to the surface of the unevenness-forming layer 2, and the resistance to the passing gas increases. There is a risk that the contained object to be sterilized cannot be effectively sterilized.

The shape of the concave-convex structure is not limited in any way, and various shapes can be selected according to the forming method and application. Examples include lines and spaces, holes, dimples, pillars, and moth-eye shapes. Among them, the moth-eye shape is particularly preferable in that the refractive index changes stepwise along the traveling direction of light, so that the reflectance can be reduced and the visibility inside the sterilization bag can be improved. Furthermore, it is not always necessary that the unevenness shape is constant over the entire surface where the unevenness forming layer 2 is arranged, and even if the unevenness shape is uneven or a plurality of kinds of unevenness shapes are mixed, it can be applied without any problem. can.

In addition, if the ruggedness forming layer 2 can secure a passage or a holding space for various gases having a sterilization effect, the surface of the transparent resin film 1 facing the air-permeable sheet 3 is not the entire surface, but only a part of the surface. There is no problem even if it is arranged. In particular, since the object to be sterilized does not come into contact with the peripheral edge portion 4, which is the adhesive surface between the transparent resin film 1 and the breathable sheet 3, there is no need to dispose the unevenness forming layer 2 on that surface. It can also be used as a face. In that case, it is possible to reduce the manufacturing cost by reducing the area for forming the unevenness. Further, the flat surface may be made of the same material as the member forming the unevenness forming layer 2, or may be made of a different material. In this case, the flat surface can be made of a member that is difficult to form unevenness, and the range of material selection is widened.

As a method for forming the unevenness-forming layer 2, a well-known fine structure forming technique suitable for the material and the shape and size of the unevenness can be appropriately selected. For example, a fine periodic structure composed of a large number of irregularities arranged at a period shorter than the wavelength of visible light can be produced using a so-called nanoimprint method. The nanoimprint method is a method of transferring a fine concave-convex structure to be formed on the surface of a substrate by applying heat, pressure, and ultraviolet rays (UV) using a mold having a shape opposite to that of the fine concave-convex structure. By using the nanoimprinting method, it is possible to manufacture a large amount easily and inexpensively and with high reproducibility.

As in this embodiment, when the uneven structure is formed in part of the lower layer of the two-layer structure and the lower layer is made of a thermoplastic resin material such as an LDPE film or an unstretched PP film, a thermal nanoimprint method is preferably used. . When using the thermal nanoimprint method, the aspect ratio of the uneven structure (the ratio of the height of the protrusions 2b or the depth D of the recesses 2a to the uneven period P; D/P) is in the range of 0.25 to 2.0. preferably 0.5 to 1.0. Here, the depth D of the concave portion 2a is a case where the top portion of the convex portion 2b is considered as a reference. When the concave-convex structure is formed by providing a plurality of concave portions 2a on a flat surface, it may be preferable to express the depth D of the concave portions 2a in this way.

Here, the unevenness period P is equal to the size of the above-described protrusions 2b when the protrusions 2b adjacent to each other are arranged in close contact with each other. Further, as described above, when the convex portions 2b are arranged adjacent to each other across a portion parallel to the surface of the continuous layer, the ratio of the size of the convex portion (length at the base of the convex portion) to the height is the aspect ratio.

If the aspect ratio is within the range described above, high transferability can be obtained with a relatively low pressing force when the thermal nanoimprinting method is used. The heating and pressing conditions for structure transfer are not particularly limited as long as the desired structure can be transferred. .

A light (ultraviolet, hereinafter referred to as UV) nanoimprinting method may be used to form the irregularity forming layer 2, in which case part or all of the transparent resin film 1 is formed of a UV curable resin. Alternatively, the transparent resin film 1 may be used as a substrate and a coating layer of a UV curable resin may be formed thereon. As the UV curable resin material, various materials can be applied, such as radical polymerization type such as acrylic and vinyl, and ion polymerization type such as epoxy and vinyl ether. Among them, epoxy-based UV-curable resins have little curing shrinkage due to the structure of the polymerization reaction (polymerization occurs while the epoxy ring is ring-opening). is more suitable for the formation of

In addition, in order to prevent mold release defects (generating pattern defects) that occur when the transfer mold is peeled off from the resin after UV curing, a fluorine-containing UV curable resin material with excellent mold release properties may be used. An organic-inorganic composite UV curable resin that is excellent in wettability, adhesion, and photocurability may be used.

Furthermore, even if a base (primer) layer is formed for the purpose of improving adhesion between the transparent resin film 1 serving as the base material and the UV curable resin layer on which the unevenness forming layer 2 is formed, nothing will happen. No problem. Examples of materials for forming such a base layer include those obtained by adding isopropyl alcohol (IPA), nitric acid, and tetraethyl orthosilicate (TEOS) to a silane coupling agent, which is a main ingredient. In addition, the surface of the transparent resin film 1 may be subjected to treatment such as UV ozone treatment or atmospheric pressure plasma treatment before forming the UV curable resin layer and the base layer.

When a roll-to-roll transfer type apparatus such as CMT-400U (manufactured by Toshiba Machine Co., Ltd.) is used to form the unevenness forming layer 2 as described above, manufacturing with high productivity and high throughput is possible. In addition, since it is compatible with the manufacturing process of other members constituting the sterilization bag of the present invention, such as the transparent resin film 1 and the breathable sheet 3, and can easily be made large, the manufacturing cost of the sterilization bag of the present invention is low. It can lead to reduction.

In addition to various structural transfer methods including the nanoimprinting method as described above, physical processing methods such as chemical processing methods such as wet/dry etching, and direct processing by high-energy light irradiation such as short pulse lasers and focused ion beams (FIB) can be applied. Any treatment method can be selected as the method for forming the irregularity forming layer 2 .

For example, the concavo-convex forming layer 2 can be formed by irradiating the substrate with a pulsed laser having an extremely short pulse width such as picoseconds or femtoseconds. By using this method, it is possible to locally form a fine uneven structure on the order of several hundred nm to several tens of μm at high speed while suppressing thermal denaturation around the processed area. In particular, femtosecond lasers are more effective because their pulse widths are shorter than the thermal relaxation time of solids (>10 ⁻¹² seconds).

A method of irradiating a femtosecond laser pulse at a laser energy density (laser fluence) in the vicinity of the lower limit of energy density (laser ablation threshold) at which processing is possible can also be used. Using this method, a fine periodic structure called LIPPS (Laser Indexed Periodic Surface Structure) having intervals equal to or less than the laser wavelength is self-organized in the direction perpendicular to the polarization direction of the incident light. It is known that This LIPPS may be used as it is as the concave-convex structure forming the concave-convex forming layer 2 .

In the sterilization process using the sterilization bag of this embodiment, an indicator (chemical indicator) may be enclosed in the sterilization bag together with the object to be sterilized. This indicator has a function of detecting various gases that act as media for sterilization and determining whether or not the sterilization process has been performed correctly by changing its color.

Paper-like chemical indicators are generally used, but if the chemical indicator adheres to the non-permeable resin film during the conventional sterilization process, the discoloration of the chemical indicator becomes insufficient, and sterilization becomes difficult. It becomes impossible to accurately determine whether processing has been performed. On the other hand, in the sterilization process using the sterilization bag of the present embodiment, the chemical indicator can be exposed to various gases by the concave-convex forming layer 2, and discoloration failure can be prevented.

In addition, the concavo-convex forming layer 2 as described above exhibits high water repellency/oil repellency, thereby preventing adhesion of dirt. Therefore, it is possible to provide a sterilization bag that is excellent in hygiene and more suitable for its intended use.

(breathable sheet)
The air-permeable sheet 3 is made of a material that allows at least one of gas, particularly hydrogen peroxide gas, EOG, and water vapor, which are media for sterilization, to permeate. In addition, it is desirable to use a material that does not allow bacteria to pass through as the breathable sheet 3 . Various gases having a sterilizing effect that have passed through the air-permeable sheet 3 efficiently enter the inside of the sterilization bag 10 and the concave portions 2a of the concave-convex forming layer 2, and can effectively sterilize the contained objects to be sterilized.

As a material for the air-permeable sheet 3, an aggregate of fibers can be used. Specific members include a non-woven fabric sheet made of fibrous resin, sterilized paper, and the like. As the nonwoven fabric sheet, one manufactured by a so-called flash spinning method may be used. In the flash spinning method, a molten thermoplastic resin is extruded from a nozzle at high pressure into filaments, which are deposited in a mesh pattern and then thermally bonded to each other to stabilize the shape. It is a method to convert An example of the thermoplastic resin used in this method is high density polyethylene (HDPE).

Nonwoven sheets made of HDPE have excellent bacterial barrier performance as well as high strength against tearing and puncture. In addition, since it is low in dust generation, by applying it to the breathable sheet 3 of the sterilization bag of the present invention, it has excellent visibility of the contents and prevents close contact with the object to be sterilized, so that effective sterilization can be performed. It is possible to provide a sterilization bag that can be performed and has excellent durability. Moreover, when LDPE or PP is used as the upper layer of the transparent resin film 1, strong heat sealing with them is possible. Therefore, there is no need to separately prepare a member or structure for forming a seal, which facilitates handling and reduces manufacturing costs. Furthermore, unlike sterilization paper whose main component is pulp (cellulose fiber), nonwoven fabric sheets made of HDPE do not adsorb hydrogen peroxide, so they can be used for hydrogen peroxide gas sterilization without any problems. preferred.

Specific examples of such nonwoven fabric sheets made of HDPE include, but are not limited to, Tyvek (Asahi DuPont Flashspun Products Co., Ltd.). Tyvek is a non-woven fabric sheet made of HDPE ultrafine continuous fibers with a diameter of 0.5 to 10 μm (average 4 μm), and its excellent air permeability, bursting strength, and high bacterial barrier properties make the breathable sheet 3 of the sterilization bag of the present invention. It is suitable as Among them, Tyvek 1073B, 1059 and 2FS (4058B) can be used more preferably.

Although HDPE is mentioned here as an example of the material of the nonwoven fabric sheet that can be applied to the breathable sheet 3, there is no particular limitation as long as it is a thermoplastic resin material that can be extruded. For example, LDPE, medium density (MDPE), PP, PET, PA (nylon 6, nylon 6, 6, etc.), polyester, ethylene copolymer (ethylene-vinyl acetate copolymer, ethylene-vinyl chloride copolymer, Ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-maleic acid copolymer, ethylene-polypropylene copolymer, ethylene-α-olefin copolymer, etc.), fluorine resin (polytetrafluoroethylene (PTFE ), perfluoroalkoxyalkane (PFA), perfluoroethylene propene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), etc.), or copolymers thereof, one or more Any of the above may be appropriately selected and used.

As a method for producing such a nonwoven fabric sheet, a method suitable for the resin material and application can be used from known spinning techniques such as melt spinning, dry/wet spinning, and electrospinning. In particular, when using the electrospray deposition method (ESD method), which is a type of electrospinning method, it is possible to produce a nonwoven fabric with a nano-sized ultrafine fiber diameter, so the thickness and pore size of the produced nonwoven fabric can be relatively easily controlled.

When the breathable sheet 3 is made of sterilized paper, the material of the sterilized paper may be 100% pulp, or the pulp base material may be coated to improve strength and durability. In addition, resins such as PE and PP may be mixed. Resin-mixed paper can be used more preferably due to additional functions such as less dust generation and heat-sealing properties.

The diameter of the cellulose fibers forming the sterilized paper is not particularly limited, but it is desirable that the diameter is larger than the size of the concave portion 2a. If the diameter of the cellulose fiber is smaller than the size of the recess 2a, the fiber may enter the recess 2a. If the fibers enter, there is a concern that the sterilization effect will be adversely affected, such as hindering expansion/contraction of the inside of the sterilization bag due to depressurization or pressurization in the sterilization process. On the other hand, when the fiber diameter is very large, it becomes difficult to control the thickness and pore size, which directly affect the gas permeability and bacterial barrier properties of the sterile paper. Therefore, the diameter of the cellulose fibers is preferably in the range of 0.4 μm to 100 μm.

The air-permeable sheet 3 may have a single-layer structure or a multi-layer structure. For example, a structure in which a nonwoven fabric film made of HDPE as described above and sterilized paper are laminated may be used.

In addition, if the air permeable sheet 3 can ensure the air permeability necessary for effectively sterilizing the items to be sterilized in the bag, there is no problem even if it has a non-air permeable part in part. do not have. In particular, the portion where the transparent resin film 1 is adhered does not need to have air permeability. In particular, when attaching by heat sealing, the transparent resin film 1 and the air-permeable sheet 3 may be softened or melted by heat and pressure during heat sealing. In this case, since the pores of the breathable sheet 3 are lost, the air permeability is inevitably lost. The portion to be heat-sealed after putting the object to be sterilized into the bag may also be made air-impermeable in advance. Although the non-breathable portion may be made of the same material as the member forming the breathable sheet 3, it is also possible to use a member made of a different material.

The thickness of the permeable sheet 3 is preferably in the range of 20 to 200 μm, more preferably in the range of 50 to 200 μm, from the standpoint of preventing bacterial invasion, maintaining strength, and maintaining air permeability and ease of handling.

(periphery)
A peripheral portion 4 shown in FIG. 1 serves as a bonded portion when forming a bag by bonding the respective ends of the transparent resin film 1 and the breathable sheet 3 together. FIG. 2 is a schematic perspective view of the sterilization bag of this embodiment. FIG. 2 shows a state in which three sides of the end of the sterilization bag 10 are bonded together as the peripheral edge 4 and the remaining one side (opening 5) is open. With such a configuration, the inside of the bag can be sealed by pasting the opening 5 after the object to be sterilized is inserted, and the sterilization process can be performed.

The peripheral portion 4 may be formed by bonding at least one side of the end portions of the transparent resin film 1 and the breathable sheet 3 . When the transparent resin film 1 and the air-permeable sheet 3 are manufactured and supplied as a roll-shaped sheet material, the peripheral edge portion 4 may be formed in such a manner that two sides of the end portions are previously bonded together along the longitudinal direction of the sheet. In this case, since the sheet material can be cut to an appropriate length according to the object to be sterilized, it is possible to provide a sterilization bag with little waste and excellent convenience.

In this embodiment, heat sealing is mainly assumed as a method of forming the peripheral portion 4, that is, a method of bonding the transparent resin film 1 and the air-permeable sheet 3 together. However, as long as sealing is ensured and the contents can be protected from recontamination by bacteria, the lamination is not limited to heat-sealing. For example, various methods can be applied, such as adhesion using an adhesive, fusion bonding using high frequency waves, ultrasonic waves, or the like. At that time, a method of forming the peripheral portion 4 having easy peelability is more preferably selected according to the materials of the transparent resin film 1 and the breathable sheet 3 .

In the present embodiment, an example in which the transparent resin film 1 and the air-permeable sheet 3 are attached to each other at their peripheral edge portions has been described. However, as for the locations where these are bonded together, they may be bonded at locations inside the peripheral edge portions along the respective peripheral edge portions.

<Second embodiment>
In the sterilization bag of this embodiment, a periodic uneven structure is formed on the uneven-formed layer 2, and the size of the convex portion 2b of the periodic uneven structure is 20 nm or more and 250 nm or less, except that the size of the convex portion 2b is 20 nm or more and 250 nm or less. Similar to morphology. In addition, in this embodiment, the description of the same configuration parts as those of the above-described first embodiment (FIG. 1) is omitted.

In this embodiment, the periodic concave-convex structure is formed with a size smaller than the wavelength of visible light (approximately 400 to 800 nm). Therefore, it is possible to prevent the transparent resin film 1 from sticking to the object to be sterilized contained in the bag, and suppress the phenomenon that the transparent resin film 1 becomes cloudy due to light scattering and the visibility inside the sterilization bag is lowered. becomes possible. That is, it is possible to suppress the influence of Mie scattering, which increases at wavelengths equal to or greater than the wavelength of light. Since Mie scattering has no wavelength dependence and is anisotropic (strong in the forward direction of light propagation), it has a great effect on the transparency of the transparent resin film 1 .

In order to further suppress the influence of Mie scattering, it is more preferable to form the periodic concave-convex structure so that the size thereof is about 1/10 or less of the wavelength of visible light. Furthermore, the smaller the size of the periodic concave-convex structure, the more the effect of Rayleigh scattering, which is dominant in the structural region sufficiently shorter than the wavelength of visible light, can be suppressed.

The period P of the periodic concave-convex structure is preferably P<400/n (nm), where n is the refractive index of the concave-convex structure (concavo-convex forming layer). Scattering is less likely to occur. LDPE and PP, which are given as examples of the material of the irregularity forming layer, have n=1.54 and n=1.49, respectively. Therefore, since the sterilization bag of the present embodiment satisfies this condition, it is a sterilization bag with excellent visibility of contents such as objects to be sterilized.

The method for forming the periodic uneven structure is not particularly limited as long as a desired structure can be obtained, but the nanoimprint method described above is suitable because the size of the unevenness is extremely small.

In the sterilization bag of this embodiment, it is possible to prevent sterilization failure due to close contact between the transparent resin film 1 and the object to be sterilized contained in the bag. In addition, since the visibility of the inclusions is excellent, it is possible to easily check the state of the sterilized object during the sterilization process. It is possible to exhibit the effect that it is possible to prevent the misunderstanding.

<Third Embodiment>
The sterilization bag of this embodiment has a periodic concave-convex structure, the size of the convex portion 2b is 150 nm or more and 400 nm or less, and the size of the convex portion 2b continuously decreases in the height direction. Other than that, it is the same as the first embodiment described above. Here, regarding the shape of the convex portion 2b, the cross-sectional area of the convex portion 2b in a plane parallel to the surface of the portion forming the continuous layer in the uneven-forming layer 2 becomes smaller as it approaches the breathable sheet 3. It can also be expressed as In addition, in this embodiment, the description of the same configuration parts as those of the above-described first embodiment (FIG. 1) is omitted.

FIG. 3 is a schematic perspective view of the concavo-convex structure in this embodiment. As shown in the diagram on the left side of FIG. 3 , in this embodiment, a periodic uneven structure 21 is formed in the uneven layer 2 . As for the shape of the convex portion of the concave-convex structure, for example, a conical convex portion 21a as shown in FIG. 3A can be used. The cross-sectional area of the projections in the plane parallel to the surface of the unevenness forming layer 2 gradually increases from the topmost portion to the bottommost portion of the projections 21a. The corresponding effective refractive index also changes continuously from the topmost portion to the bottommost portion of the convex portion 21a. That is, it has a smooth effective refractive index distribution toward the transparent resin film 1 from the outermost layer inside the sterilization bag (inclusion side). Therefore, when light is incident on the periodic concave-convex structure 21, the light reaches the transparent resin film 1 without being reflected because there is no sharp refractive index difference. Therefore, the sterilization bag is excellent in visibility of the contents such as objects to be sterilized.

The shape of the projections in the periodic concave-convex structure 21 of the present embodiment is not limited to the conical shape illustrated in FIG. 3(a). That is, if the width of the convex portion 2b changes continuously in the height direction, a shape suitable for the purpose can be appropriately selected without particular limitation, including a bell-shaped shape. For example, a triangular pyramid-shaped projection 21b shown in FIG. 3(b) or a quadrangular pyramid-shaped projection 21c shown in FIG. 3(c) may be used. These shapes, including the conical shape illustrated in FIG. 3A, are particularly preferable because the continuous change in the refractive index in the height direction of the convex portion is linear (proportional to a linear function).

There is no particular limitation on the method of periodically arranging the concave-convex structure, but if it is a hexagonal close-packed arrangement as shown on the left side of FIG. Also, the method for forming the periodic concave-convex structure is not particularly limited as long as the desired structure can be obtained.

<Fourth Embodiment>
The sterilization bag of this embodiment is the same as the first embodiment described above except that the surface of the transparent resin film 1 opposite to the breathable sheet 3 side has a fine periodic uneven structure different from the surface of the breathable sheet side. Similar to morphology. In addition, in this embodiment, the same code|symbol is attached|subjected about the same component as 1st Embodiment (FIG. 1) mentioned above, and detailed description is abbreviate|omitted.

FIG. 4 is a schematic cross-sectional view of the sterilization bag according to this embodiment. The sterilization bag 110 of this embodiment has an uneven layer 20 in which concave portions 20 a and convex portions 20 b are periodically formed on the surface of the transparent resin film 1 facing the air-permeable sheet 3 . Further, a fine periodic uneven structure 6 is also formed on the surface of the transparent resin film 1 opposite to the surface on which the uneven-formed layer 20 is formed (outer side of the bag-shaped sterilization bag).

The fine periodic uneven structure 6 is not particularly limited in its shape and size, but may have the same structure as the periodic uneven structure described in the second and third embodiments of the present invention. can. With such a configuration, the above-described light scattering reduction effect and light reflection prevention effect can be obtained on both surfaces of the transparent resin film 1, so that the visibility of the inclusion can be further enhanced. Of course, the concave-convex forming layer 20 and the fine periodic concave-convex structure 6 may have different shapes and sizes to perform different functions. Moreover, there is no problem even if the fine periodic concave-convex structure 6 is arranged not on the entire surface of the transparent resin film 1 but only on a part thereof.

The method for forming the fine periodic concave-convex structure 6 is not particularly limited as long as a desired structure can be obtained. In particular, when a resin with relatively high heat resistance such as biaxially stretched PET, PEN, or PA is used as the material for the transparent resin film 1, the resin is used as a base material, and a UV curable resin is applied thereon to obtain a UV curable resin. It is desirable to form by a nanoimprint method.

<Other embodiments>
Although the first to fourth embodiments of the present invention have been described above in detail, the present invention is not limited to each of the above-described embodiments. For example, the above-described embodiments assume sterilization bags for processing medical instruments such as forceps, syringes, and endoscopes as objects to be processed. However, the present invention is not limited to this, and can be applied to, for example, sterilization bags used for sterilizing various sanitary products, instruments for scientific experiments, industrial instruments, and the like. In addition, the present invention can be applied not only to sterilization but also to scientific/industrial processing applications that require gas exposure of inclusions.

REFERENCE SIGNS LIST 1 transparent resin film 2 concave-convex forming layer 3 breathable sheet 4 peripheral edge

Claims (7)

A sterilization bag comprising a bag body in which a transparent resin film and a sheet made of an air-permeable material are attached to each other along at least one side along each peripheral edge,
A sterilization bag, wherein the transparent resin film has an uneven structure on the surface thereof facing the sheet. 2. The sterilization bag according to claim 1, wherein the size of the projections of the uneven structure is 20 nm or more and 50 μm or less. 3. The sterilization bag according to claim 2, wherein the concave-convex structure is a periodic concave-convex structure, and the size of the convex portion is 20 nm or more and 250 nm or less. The uneven structure is a periodic uneven structure, the size of the protrusion is 150 nm or more and 400 nm or less, and the cross-sectional area of the protrusion in a plane parallel to the surface decreases as it approaches the sheet. 3. The sterilization bag of claim 2, wherein the sterilization bag is a. 5. The sterilization bag according to any one of claims 1 to 4, wherein the sheet is made of an aggregate of fibers having a diameter larger than the size of the concave portions of the concave-convex structure. 6. The sterilization bag according to any one of claims 1 to 5, wherein the concave-convex structure of the transparent resin film is formed on a surface other than a surface to be bonded with the sheet. The sterilization bag according to any one of claims 1 to 6, wherein the surface of the transparent resin film opposite to the side facing the sheet has a fine periodic uneven structure.

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