JP2001310406A - High moisture permeable film, bag for packaging by dealing with high moisture permeability, mushroom packaging sealing bag, fermented soybean packaging sealing bag and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high moisture permeable film capable of suitably controlling a permeating amount of a gas like an oxygen and having an excellent steam permeability including a steam permeating amount at 40 deg., 90% RH of 100 g/m2.24 hr or more. SOLUTION: The high moisture permeable film comprises a laminated film containing an organic polymer film having rigidity and a water-soluble organic polymer film, and many fine through holes perforated in a thickness direction of the laminated film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly moisture-permeable film, a highly moisture-permeable packing bag, a mushroom packaging sealed bag, a natto packaging sealed bag, and a method for producing the same.

[0002]

2. Description of the Related Art In the field of food packaging, development of packaging materials having high moisture permeability is required. For example, polypropylene (biaxially oriented polypropylene) as a general-purpose organic polymer film, polyethylene,
Water vapor permeation rate at 0% RH is 5 g / m ² · 24 each.
hr or less, 5 g / m ² · 24 hr or less. When fruits and vegetables such as mushrooms are stored in a packaging bag made of such a general-purpose organic polymer film and sealed, water vapor evaporating from itself cannot be sufficiently released to the outside. Causes decay.

[0003] For this reason, conventionally, in order to package mushrooms (for example, raw shiitake mushrooms), raw shiitake mushrooms are placed on a plastic tray at a production site, and the tray containing the raw shiitake mushrooms has a high water vapor permeability, that is, is transparent. It has been practiced to wrap the raw shiitake mushrooms in a plastic net or wrap them with a film made of wet polyvinylidene chloride. However, when the raw shiitake mushrooms are stored for a long period of time in the former packaging form, there is a possibility that dew condensation may occur at a portion that comes into contact with the tray, causing partial decay. In addition, packaging raw shiitake mushrooms through two processes is not only time-consuming, but also has the problem of high packaging costs. In the latter packaging form, although the packaging cost is low, the stored shiitake mushrooms breathe excessively and grow because of the high permeation of gas such as oxygen. And the commercial value drops significantly.

On the other hand, natto is known as another example of a food packaged with a packaging material having high moisture permeability. Due to recent diversification of foods, natto is available in individual wraps for one meal. This natto has been conventionally produced by the following method.

(1) Boiled soybeans and natto bacteria are put in a plastic cup and fermented in an open state at a temperature of 37 to 41 ° C. for 18 to 24 hours (the temperature is controlled to about 50 ° C. in the latter half of the fermentation). Subsequently, after placing a bag of soy sauce and poppy in the cup, a lid made of a sealant film such as a polyethylene film having a large number of needle holes was heat-sealed to the opening of the container, and then sealed at 4 ° C. To produce individually packaged natto by aging for 1 day. The lid made of a sealant film such as a polyethylene film having a large number of needle holes plays a role of releasing water vapor generated from natto during ripening and storage to the outside.

(2) Boiled soybeans and Bacillus natto are put in a styrofoam rectangular container with a lid, and fermented at a temperature of 37 to 41 ° C. for 18 to 24 hours with the lid opened (50 ° C. in the latter half of fermentation). Temperature control before and after). Subsequently, a perforated film was placed on the fermented soybean, and then a bag of soy sauce and poppy was placed on the film, and the lid and the container were heat-sealed at a position opposite to the base of the lid, and then heated at 4 ° C. To produce individually packaged natto by aging for 1 day. The water vapor generated from natto during ripening and storage is released to the outside through a gap between the lid and the container.

However, the individually packaged natto of (1) uses a lid made of a sealant film having a plastic cup and a needle hole as a packaging material, and the individually packaged natto of (2) uses a polystyrene foam with a lid as a packaging material. Since the rectangular container and the perforated film are used, the packaging cost increases. After fermenting the boiled soybeans, it is necessary to heat seal a sealant film having a needle hole in the cup in the case of (1), and to heat seal a styrofoam lid in the same container in the case of (2). Therefore, the process becomes complicated, the production cost rises and the equipment cost also rises.

[0008]

DISCLOSURE OF THE INVENTION The present invention can control the permeation amount of a gas such as oxygen at 40 ° C., 90%
An object of the present invention is to provide a highly moisture-permeable film having an excellent water vapor permeability of 100 g / m ² · 24 hr or more in RH.

According to the present invention, the amount of permeation of a gas such as oxygen can be appropriately controlled and the amount of water vapor permeated at 40 ° C. and 90% RH is 100 g / m ² · 24 hr or more. Another object of the present invention is to provide a highly moisture-permeable packaging bag that can be easily torn.

[0010] The present invention provides a bag capable of appropriately controlling the permeation amount of a gas such as oxygen and having an excellent water vapor permeability of 100 g / m ² · 24 hr or more at 40 ° C. and 90% RH. It is an object of the present invention to provide a low-cost sealed mushroom packaging bag which can maintain the freshness of mushrooms stored in the bag for a long period of time and can be easily torn.

According to the present invention, the amount of permeation of gas such as oxygen can be appropriately controlled, and the amount of water vapor permeated at 40 ° C. and 90% RH is 100 g / m ² · 24 hr or more (more preferably 5 g / m ² · 24 hr).
(Greater than 00 g / m ² · 24 hr) with a bag having excellent water vapor permeability, which can maintain the freshness of natto stored in the bag for a long period of time and can be easily torn. It is an object of the present invention to provide a natto packaging sealed bag having a structure.

According to the present invention, the amount of permeation of gas such as oxygen can be appropriately controlled, and the amount of water vapor permeated at 40 ° C. and 90% RH is 100 g / m ² · 24 hr or more (more preferably 5 g / m ² · 24 hr).
Comprising a bag having excellent water vapor permeability of 00g / m ² · 24hr or more), the soybean and natto housed boiled in a bag, after sealing, fermentation, capable of performing aging continuously natto It is an object of the present invention to provide a method for manufacturing a sealed package.

[0013]

According to the present invention, there is provided a highly moisture-permeable film comprising a laminated film including a rigid organic polymer film and a water-soluble organic polymer film, and a film extending in the thickness direction of the laminated film. And a large number of fine through holes.

In the highly moisture-permeable film according to the present invention,
The water-soluble organic polymer film is preferably a polyvinyl alcohol film.

In the highly moisture-permeable film according to the present invention,
The water-soluble polymer film preferably has a thickness of 3 μm or more.

In the highly moisture-permeable film according to the present invention,
It is preferable that the plurality of fine through holes have an average opening diameter of 0.5 to 100 μm and are formed in the thickness direction of the laminated film at a density of 500 / cm ² or more.

In the highly moisture-permeable film according to the present invention,
The water vapor transmission rate at 40 ° C. and 90% RH is 100 g / m ^2.
-It is preferable that it is 24 hours or more.

Another highly moisture-permeable film according to the present invention comprises a rigid organic polymer film, a sealant film and a water-soluble organic polymer film, wherein the water-soluble organic polymer film is interposed therebetween. And a large number of fine through-holes drilled in the thickness direction of the laminated film.

In another highly moisture-permeable film according to the present invention, the water-soluble organic polymer film is preferably a polyvinyl alcohol film.

In another highly moisture-permeable film according to the present invention, the water-soluble polymer film preferably has a thickness of 3 μm or more.

In another highly moisture-permeable film according to the present invention, the plurality of fine through-holes have an average opening diameter of 0.5 to 100 μm, and have a density of 500 / cm ² or more. Preferably, it is formed over the thickness direction.

In another highly moisture-permeable film according to the present invention, the amount of water vapor permeated at 40 ° C. and 90% RH is 100 g /
m ² · 24 hr or more.

The highly moisture-permeable packaging bag according to the present invention is provided with a laminated film including a rigid organic polymer film and a water-soluble organic polymer film, and perforated in the thickness direction of the laminated film. And a highly moisture-permeable film having a large number of fine through holes.

In the bag for packaging with high moisture permeability according to the present invention, the plurality of fine through holes have an average opening diameter of 0.5 to 100 μm and a density of 500 or more per cm ^2. Is preferably formed in the thickness direction.

In the highly moisture-permeable packaging bag according to the present invention, the highly moisture-permeable film preferably has a water vapor transmission rate at 40 ° C. and 90% RH of 100 g / m ² · 24 hr or more.

The highly moisture-permeable packaging bag according to the present invention preferably has a pillow-type structure in which one end of a cylindrical body having a sealing portion in the length direction is heat-sealed.

Another packaging bag for high moisture permeability according to the present invention comprises a rigid organic polymer film, a sealant film and a water-soluble organic polymer film, wherein the water-soluble organic polymer film is interposed therebetween. And a highly moisture-permeable film having a large number of fine through holes perforated in the thickness direction of the laminated film.

In another packaging bag for high moisture permeability according to the present invention, the large number of fine through-holes are 0.5 to 100 μm.
Is preferably formed at a density of 500 / cm ² or more in the thickness direction of the laminated film.

In another packaging bag for high moisture permeability according to the present invention, the high moisture permeable film preferably has a water vapor transmission rate at 40 ° C. and 90% RH of 100 g / m ² · 24 hr or more.

[0030] The mushroom packaging and sealing bag according to the present invention comprises a laminated film including a rigid organic polymer film and a water-soluble organic polymer film, and a plurality of fine holes perforated in the thickness direction of the laminated film. With a through hole
In addition, mushrooms are stored in an unsealed bag having an opening portion, and the water-soluble organic polymer films in the opening portion are sealed by heat sealing.

In the sealed bag for packaging mushrooms according to the present invention, the plurality of fine through holes have an average opening diameter of 0.5 to 100 μm and a thickness of the laminated film at a density of 500 / cm ² or more. Preferably, it is formed over the directions.

[0032] In the sealed bag for packaging mushrooms according to the present invention, it is preferable that the high moisture permeable film has a water vapor transmission rate at 40 ° C and 90% RH of 100 g / m ² · 24 hr or more.

The natto packaging and sealing bag according to the present invention comprises a rigid organic polymer film, a sealant film and a water-soluble organic polymer film, wherein the water-soluble organic polymer film is interposed between the laminated film and the laminated film. A natto is made of a highly moisture-permeable film having a large number of fine through holes perforated in the thickness direction of the laminated film, and natto is stored in an unsealed bag having an opening portion, and the sealant film of the opening portion is provided. It is characterized by being sealed by heat sealing each other.

In the natto packaging and sealing bag according to the present invention, the plurality of fine through-holes have an average opening diameter of 0.5 to 100 μm and a thickness of the laminated film at a density of 500 / cm ² or more. Preferably, it is formed over the directions.

In the natto packaging / sealing bag according to the present invention, it is preferable that the highly moisture-permeable film has a water vapor transmission rate at 40 ° C. and 90% RH of 500 g / m ² · 24 hr or more.

The method for producing a natto packaging sealed bag according to the present invention comprises a rigid organic polymer film, a sealant film and a water-soluble organic polymer film, wherein the water-soluble organic polymer film is interposed therebetween. It is composed of a film and a highly moisture-permeable film having a large number of fine through holes perforated in the thickness direction of the laminated film,
And storing the boiled soybeans and Bacillus natto in an unsealed bag having an opening portion, and after sealing the sealant films of the opening portion with each other by heat sealing, fermenting the boiled soybeans in the presence of the Bacillus natto, And an aging step.

[0037] In the method for producing a sealed natto packaging bag according to the present invention, the plurality of fine through holes may have a size of 0.5 to 100 µm.
Is preferably formed at a density of 500 / cm ² or more in the thickness direction of the laminated film.

In the method for producing a sealed natto packaging bag according to the present invention, it is preferable that the high moisture permeable film has a water vapor transmission rate at 40 ° C. and 90% RH of 500 g / m ² · 24 hr or more.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, two types of highly permeable films according to the present invention, two types of highly permeable packaging bags, mushroom packaging sealed bags,
The natto packaging sealed bag and the method for producing the natto packaging sealed bag will be described in detail.

1) Highly moisture-permeable film This highly moisture-permeable film is formed by laminating a laminated film containing a rigid organic polymer film and a water-soluble organic polymer film, and extending in the thickness direction of the laminated film. And a large number of fine through holes.

Here, the term "laminated film" refers to a form in which a water-soluble organic polymer film is directly laminated by applying a water-soluble organic polymer to a rigid organic polymer film and drying the film, or a film of the organic polymer film. This refers to a form in which a water-soluble organic polymer film is applied to the adhesive layer and dried to laminate a water-soluble organic polymer film via the adhesive layer. As the adhesive, for example, a urethane-based adhesive can be used.

Specifically, as shown in FIG. 1, this highly moisture-permeable film is formed by laminating a number of fine through holes 4 in a laminated film 3 of a rigid organic polymer film 1 and a water-soluble organic polymer film 2. Has a structure perforated in the thickness direction of the laminated film 3.

As the organic polymer having rigidity, for example, polyethylene terephthalate (PET), nylon, polypropylene (including oriented polypropylene) and the like can be used. The organic polymer film comprises:
It can be used in the form of a layer or two or more layers. The organic polymer film preferably has a thickness of 12 to 30 μm. When a polypropylene film having poor adhesion to a water-soluble organic polymer is used as the rigid organic polymer film, the water-soluble organic polymer film is laminated on the polypropylene film via an adhesive layer. Is preferred. On the other hand, when a PET film or a nylon film having high adhesiveness to a water-soluble organic polymer is used as the rigid organic polymer film, the water-soluble organic polymer film is made of PE.
It can be directly laminated on a T film or a nylon film by a coating method.

Examples of the water-soluble organic polymer include at least one selected from polyvinyl alcohol (PVA) and ethylene vinyl alcohol copolymer (EVOH). In particular, the former polyvinyl alcohol is preferable because it is less expensive than the latter ethylene vinyl alcohol copolymer. This water-soluble organic polymer film preferably has a thickness of 3 to 10 μm.

The number of fine through holes is 0.5 to 10
It is preferable that the laminated film has an average opening diameter of 0 μm and a density of 500 / cm ² or more over the thickness direction of the laminated film. In particular, when a large number of through holes 4 have a V-shaped or U-shaped cross section as shown in FIG.
Preferably, the average opening diameter on the large opening side is 10 to 300 μm, and the average opening diameter on the small opening diameter side is 0.1 to 50 μm.

The reason why the average opening diameter of the through hole is defined is as follows.
This is for the following reasons. When the average opening diameter of each of the through holes is less than 0.5 μm, it becomes difficult to obtain a laminated film having high water vapor permeability. On the other hand, if the average opening diameter of each of the through holes exceeds 100 μm, the amount of gas permeation of oxygen or the like may increase. More preferably, the average opening diameter of each of the through holes is 5 to 80 μm.

The formation density of the through holes with respect to the laminated film is specified for the following reason. If the formation density of the through holes is less than 500 / cm ² , it becomes difficult to obtain a highly moisture-permeable film having high water vapor permeability. More preferably, the formation density of the through holes is 1000 holes / cm ² or more. The upper limit of the formation density of the through holes is preferably 5000 / cm ² from the viewpoint of suppressing the permeation amount of gas such as oxygen.

The highly moisture-permeable film according to the present invention is disclosed in, for example, Japanese Patent Publication No. 6-61859 invented by the present inventor on a laminated film of the above-mentioned rigid organic polymer film and a water-soluble organic polymer film. It is manufactured by forming a large number of fine through holes using the disclosed apparatus for manufacturing a porous film.

The above-mentioned apparatus for producing a porous film is provided with a supply means for supplying a long laminated film; a rotatable member having a plurality of particles having a Mohs hardness of 5 or more (eg, diamond particles) having sharp corners adhered to the surface. A first roll, and a second roll rotatable in the opposite direction to the roll, wherein the first and second rolls are arranged to face each other and the long film passes between them. A perforating unit in which one of the rolls is fixed and the other is movably arranged in the direction opposite to the one roll; and near both ends of the movable roll of the unit. And pressure adjusting means for adjusting the pressing force of the rolls on the film.

2) Highly moisture-permeable film This highly moisture-permeable film includes a rigid organic polymer film, a sealant film and a water-soluble organic polymer film, and is a laminate in which the water-soluble organic polymer film is interposed. It has a structure including a film and a large number of fine through holes formed in the thickness direction of the laminated film.

Here, the term “laminated film” means that a water-soluble organic polymer film is applied directly to a rigid organic polymer film and dried to directly laminate the water-soluble organic polymer film. A form in which a sealant film is laminated via an adhesive layer, or a method in which a water-soluble organic polymer film is laminated through an adhesive layer by applying and drying a water-soluble organic polymer on the adhesive layer of an organic polymer film. And a form in which a sealant film is laminated on the water-soluble polymer film via an adhesive layer. As the adhesive, for example, a urethane-based adhesive can be used.

More specifically, as shown in FIG. 2, this highly moisture-permeable film is formed by applying a water-soluble organic polymer to a rigid organic polymer film 11 and drying it to form a water-soluble organic polymer film 12. This water-soluble organic polymer film 1
A large number of fine through holes 16 are formed in a laminated film 15 in which a sealant film 13 is adhered to the laminated film 2 via an adhesive layer 14 in the thickness direction of the laminated film 15.

As the above-mentioned rigid organic polymer and water-soluble organic polymer, the same ones as described in the above-mentioned 1) high moisture permeable film can be used.

As the sealant film, a polyethylene film (including a low density polyethylene and a linear low density polyethylene film), a non-oriented polypropylene film, an ionomer resin film and the like can be used. This sealant film preferably has a thickness of 30 to 40 μm.

The number of the fine through holes is 0.5 to 10
0 μm, more preferably having an average opening diameter of 5 to 80 μm, and at least 500 / cm ² , more preferably 100
0 pieces / cm ² or more (especially the upper limit is 5000 pieces / cm ² )
It is desirable to be formed over the thickness direction of the laminated film at a density of. In particular, when a large number of through holes 4 have a V-shaped or U-shaped cross section as shown in FIG.
Preferably, the average opening diameter on the large opening side is 10 to 300 μm, and the average opening diameter on the small opening diameter side is 0.1 to 50 μm.

The through hole has an average opening diameter of 0.5 to 100.
The reason why the formation density is specified to be 500 μm / cm ² or more is for the same reason as described for the highly moisture-permeable film in 1) above.

The highly moisture-permeable film according to the present invention is, for example, a laminated film in which a water-soluble organic polymer film is interposed between an organic polymer film having rigidity and a sealant film as described above. 6-618
It is manufactured by forming a large number of fine through holes using a porous film manufacturing apparatus disclosed in JP-A-59-59.

3) Highly moisture-permeable packaging bag For example, as shown in FIG.
Is formed by folding the highly moisture-permeable film 22 in such a manner that the water-soluble organic polymer film (not shown) is located inside, and heat-sealing the water-soluble polymer films together at the ends thereof. 23 is bent so as to come into contact with a rigid organic polymer film (not shown) outside the highly moisture-permeable film 22 to form a cylindrical body, and one end of the cylindrical body is heat-sealed to form a seal portion 24; This seal part 24
Has a pillow-type structure in which the opposite end is opened. As shown in FIG. 4, the highly moisture-permeable film 22 has a large number of fine through holes 28 in a laminated film 27 having a rigid organic polymer film 25 and a water-soluble organic polymer film 26. It has a structure pierced in the vertical direction.

The same high moisture permeable film as described in the above 1) is used.

The packaging bag for high moisture permeability is not limited to the pillow type described above. The highly moisture permeable film of 1) is folded in two so that the water-soluble organic polymer film is located inside, and the folded bag is folded. Even in a pouch-type structure in which the water-soluble polymer films are heat-sealed with each other at two ends excluding the bent portion, the highly moisture-permeable film is folded in two so that the water-soluble organic polymer film is located inside, A cup-type structure in which a cup is formed by drawing and forming the highly moisture-permeable film described above.

The number of the fine through holes is 0.5 to 10
It is preferable that the laminated film has an average opening diameter of 0 μm and a density of 500 / cm ² or more over the thickness direction of the laminated film.

The reason why the average opening diameter of the through hole is defined is as follows.
This is for the following reasons. When the average opening diameter of each of the through holes is less than 0.5 μm, it becomes difficult to obtain a bag having high water vapor permeability. On the other hand, when the average opening diameter of each of the through holes exceeds 100 μm, the amount of permeation of gas such as oxygen increases, and the respiration and growth of fruits and vegetables (for example, mushrooms) stored in the bag are promoted, and the released water vapor increases. . As a result, even if the bag has high moisture permeability, the escape of water vapor to the outside cannot catch up, and there is a possibility that dew may be formed on the inner surface of the bag and the fruits and vegetables may be spoiled. More preferably, the average opening diameter of each of the through holes is 5 to 80 μm.

The reason why the formation density of the through-holes with respect to the laminated film is specified is as follows. If the formation density of the through holes is less than 500 / cm ² , it becomes difficult to obtain a bag having high water vapor permeability. More preferably, the formation density of the through holes is 1000
Pieces / cm ² or more. The upper limit of the formation density of the through holes is preferably 5000 / cm ² from the viewpoint of suppressing the permeation amount of gas such as oxygen.

Such a packaging bag for high moisture permeability can be applied to storage of fruits and vegetables, such as mushrooms such as shiitake mushrooms and green soybeans from which stems are removed, which emit a large amount of water vapor, natto, and the like.

4) Highly moisture-permeable packaging bag For example, as shown in FIG.
Is to fold the highly moisture-permeable film 32 in such a manner that its sealant film (not shown) is located inside, heat-seal the sealant films at their ends, and attach the seal portion 33 to the highly moisture-permeable film 32. Is bent so as to come into contact with an organic polymer film (not shown) having rigidity, and one end of the cylindrical body is heat-sealed to form a seal portion 34. It has a pillow-type structure with an open end. As shown in FIG. 6, the highly moisture-permeable film 32 is formed, for example, by applying a water-soluble organic polymer to a rigid organic polymer film 35 and drying to form a water-soluble organic polymer film 36. A laminated film 39 in which a sealant film 37 is adhered to a film 36 via an adhesive layer 38 has a structure in which a number of fine through holes 40 are perforated in the thickness direction of the laminated film 39.

As the high moisture permeable film, the same one as described in the above 2) is used.

The high moisture-permeable packaging bag is not limited to the pillow type described above. The highly moisture-permeable film of the above 2) is folded in two so that the sealant water-soluble organic polymer film is located on the inner side. Even in a pouch type structure in which the water-soluble polymer films are heat-sealed at two ends excluding the bent portion, the highly moisture-permeable film is folded in two so that the sealant film is located inside, and one of the highly-permeable films is folded. A cup-type structure in which a wet film is drawn and formed into a cup may be used.

The large number of fine through holes correspond to the height of the above 3).
For the same reasons as described for the moisture-permeable packaging bag
Having an average opening diameter of 0.5 to 100 μm and 500 pieces
/ Cm ^TwoWith the above density in the thickness direction of the laminated film
Is preferably formed.

Such a packaging bag with high moisture permeability can be applied to storage of fruits and vegetables, such as mushrooms such as shiitake mushrooms and green soybeans from which stems have been removed, which emit a large amount of water vapor, natto, and the like.

5) Sealing bag for mushrooms This packing bag for mushrooms contains, for example, mushrooms such as raw shiitake mushrooms in the highly moisture-permeable packing bag of the above 3), and heat seals the opened portion to obtain the raw shiitake mushrooms. Has a sealed structure.

More specifically, as shown in FIG. 7, a sealed bag 51 for mushrooms is formed by placing a plurality of mushrooms (for example, raw shiitake mushrooms) 52 in the highly moisture-permeable packing bag 21 shown in FIGS. It is housed through the opening portion, and has a structure in which the water-soluble organic polymer films on the inner surface of the opening portion are heat-sealed with each other to form a sealing portion 53, thereby sealing the film.

6) Natto packaging and sealing bag This natto packaging and sealing bag has a structure in which natto is stored in, for example, the packaging bag for high moisture permeability described in 4), and the opening portion is heat-sealed to seal the mushroom. .

Specifically, as shown in FIG. 8, the natto packaging sealed bag 61 has a large number of natto 62 accommodated in the highly moisture-permeable packaging bag 31 shown in FIGS. The sealant film on the inner surface of the unsealing portion is heat-sealed with each other to form a sealing portion 63, which is hermetically sealed.

The packaging bag for high moisture permeability is 40 ° C., 9
Water vapor permeation rate at 0% RH is 500 g / m ² · 24 hr
It is preferable that it is above.

7) Manufacturing method of natto packaging sealed bag First, after storing boiled soybeans and natto bacteria in the highly moisture-permeable packaging bag shown in FIGS. 5 and 6 described above, the bag is placed on the inner surface of the opened portion of the bag. The sealant films to be sealed are heat-sealed. Subsequently, the boiled soybean is fermented and aged in the presence of the Bacillus natto to produce a natto packaging sealed bag. At this time, since the highly moisture-permeable packaging bag uses a highly moisture-permeable film having a large number of fine through holes as a base film as described above, steam generated from boiled soybeans and natto during the fermentation and ripening is used. Can escape sufficiently to the outside.

The packaging bag for high moisture permeability is 40 ° C., 9
Water vapor permeation rate at 0% RH is 500 g / m ² · 24 hr
It is preferable that it is above.

The fermentation is carried out at a temperature of 37-41 ° C. for 18 hours.
It is preferably performed for up to 24 hours. In the latter half of the fermentation, 50
It is preferable to control the temperature to about ° C.

The aging is preferably performed at 4 ° C. for about one day.

The highly moisture-permeable film according to the above-mentioned 1) according to the present invention comprises a rigid organic polymer film such as OPP and PET and a water-soluble organic polymer film such as polyvinyl alcohol. And a structure having a plurality of fine through-holes formed in the thickness direction of the laminated film. Surprisingly, a highly moisture-permeable film having such a structure cannot be achieved at all with a porous film in which a large number of fine through holes are formed in a film of an organic polymer having rigidity such as PET. 100 g / m ^{2 at} 40 ° C. and 90% RH
-High water vapor permeability of 24 hours or more. Also, the amount of permeation of a gas such as oxygen can be controlled.

The high water vapor permeability of the highly moisture permeable film according to the present invention is that when a large number of fine through holes are formed in the laminated film, a water-soluble organic polymer such as polyvinyl alcohol is used. This is because the film has an action of inducing water vapor (action of attracting water vapor), and the water vapor escapes to the outside of the OPP film through the through hole of the OPP film that is integrally communicated with the through hole of the film. It is estimated to be.

In particular, the large number of fine through-holes is 0.5 to
It has an average opening diameter of 100 μm and has 500 openings / cm ²
The highly moisture-permeable film formed at the above density in the thickness direction of the laminated film has a higher water vapor permeability of 1000 g / m ² · 24 hr or more at 40 ° C. and 90% RH.

The highly moisture-permeable film according to the present invention is formed by laminating a large number of fine through-holes with a rigid organic polymer film such as OPP and a water-soluble organic polymer film such as polyvinyl alcohol. Drilled in the film, the through-hole acts as a tearing starting point, so that it can be easily torn and has excellent tearability.

The highly moisture-permeable film according to 2) according to the present invention may be a rigid organic polymer film such as OPP or PET, a water-soluble organic polymer film such as polyvinyl alcohol, or a polyethylene film. A laminated film including a transparent sealant film and the polyvinyl alcohol film interposed therebetween, and a large number of fine through holes perforated in the thickness direction of the laminated film. Surprisingly, a highly moisture-permeable film having such a structure can be achieved by a film of an organic polymer having a rigidity such as PET or a porous film in which a number of fine through holes are formed in a sealant film. It has a high water vapor permeability of 100 g / m ² · 24 hr or more at 40 ° C. and 90% RH. Also, the amount of permeation of a gas such as oxygen can be controlled.

The high moisture-permeable film according to the present invention has a high water vapor transmission rate because a large number of fine through-holes are formed in the laminated film, for example, the film is interposed between the OPP film and the polyethylene film. A film of a water-soluble organic polymer such as polyvinyl alcohol exhibits a steam-inducing action (steam-introducing action). For example, the water vapor on the polyethylene film side causes fine through-holes in this film and through-holes in the polyvinyl alcohol film. The water vapor diffuses quickly and smoothly through the polyvinyl alcohol film, and the diffused water vapor is integrated with the through hole of the polyvinyl alcohol film.
This is presumed to be due to escape to the outside through the through holes of the PP film.

In particular, the number of the fine through holes is 0.5 to
It has an average opening diameter of 100 μm and has 500 openings / cm ²
The highly moisture-permeable film formed at the above density in the thickness direction of the laminated film has a higher water vapor transmission rate of 1000 g / m ² · 24 hr or more at 40 ° C. and 90% RH.

In the highly moisture-permeable film according to the present invention, a large number of fine through-holes are formed in the laminated film, and the through-holes function as tearing starting points. Has easy tearability.

The highly moisture-permeable packaging bag of 3) according to the present invention uses the highly moisture-permeable film described in 1) as a base film.
It has a high water vapor permeability of 0 g / m ² · 24 hr or more,
In addition, the amount of permeation of a gas such as oxygen can be controlled. As a result, vegetables and the like are stored in the bag, and the opened portion is heat-sealed, so that water vapor generated by breathing by the fruits and vegetables during storage can be satisfactorily escaped to the outside of the bag. Can prevent the decaying of fruits and vegetables by suppressing the occurrence of dew condensation.

Further, the highly moisture-permeable film is formed by forming a large number of fine through-holes in a laminated film including an organic polymer film having rigidity such as OPP and a water-soluble organic polymer film such as polyvinyl alcohol. Since the through hole functions as a tearing starting point, the highly moisture-permeable packaging bag made of the highly moisture-permeable film can be easily torn when the contents are opened.

The highly moisture-permeable packaging bag according to 4) according to the present invention uses the highly moisture-permeable film described in 2) as a base film.
It has a high water vapor permeability of 0 g / m ² · 24 hr or more,
In addition, the amount of permeation of a gas such as oxygen can be controlled. As a result, the vegetables and the like are stored in the bag, and the heat-sealing of the opened portion allows the water vapor generated by breathing by the fruits and vegetables during storage to escape well to the outside of the bag. Can prevent the decaying of fruits and vegetables by suppressing the occurrence of dew condensation.

The highly moisture-permeable film is a film of an organic polymer having a large number of fine through-holes having rigidity such as OPP, a film of a water-soluble organic polymer such as polyvinyl alcohol, and a sealant such as a polyethylene film. Including a film, the polyvinyl alcohol film is pierced in a laminated film interposed in the middle, and the through-hole acts as a tearing starting point. Can be easily torn when opened.

The sealed bag for mushroom packaging according to 5) of the present invention comprises:
100 ° C at 40 ° C and 90% RH described in 3) above.
mushrooms such as raw shiitake mushrooms are stored in a highly moisture-permeable packaging bag having a high water vapor transmission rate of at least g / m ² · 24 hr and capable of controlling the transmission of gas such as oxygen. It has a structure in which the unsealing portion is sealed by heat sealing, and water vapor generated by breathing by the raw shiitake mushroom can be satisfactorily escaped to the outside of the bag during storage, thereby suppressing the occurrence of dew condensation on the bag inner surface. To prevent rotting of raw shiitake mushrooms. In addition, since the amount of permeation of gas such as oxygen is controlled, it is possible to prevent the raw shiitake mushrooms from excessively breathing during storage and thereby increasing the amount of released water vapor.

In addition, the sealing bag is provided with a number of fine through-holes, and the through-holes function as tearing starting points, so that the raw shiitake can be easily torn when opened.

Further, since the sealed bag is made of the above-described high moisture permeable film alone, the cost is significantly reduced as compared with the case where the sealing bag is composed of a tray and a wrap film having high moisture permeability as in the case of the conventional mushroom packaging material. be able to.

Therefore, it is possible to provide a low-cost sealed bag for mushroom packaging that can maintain the freshness of mushrooms for a long period of time and can be easily torn.

The natto packaging and sealing bag according to the above 6) according to the present invention is the same as the one described in the above 4) at 40 ° C. and 90% RH.
00 g / m ² · 24 hr or more (more preferably 500 g
/ M ² · 24 hr or more), the natto is stored in a highly moisture-permeable packaging bag capable of controlling the amount of gas transmission such as oxygen, and heat-sealing the opened portion. It has a hermetically sealed structure, and the steam generated by the respiration by the natto at the time of storage and ripening can be satisfactorily escaped to the outside of the bag, so that the natto can be prevented from spoiling. In addition, since the amount of permeation of a gas such as oxygen is controlled, it is possible to suppress an increase in the amount of released steam due to excessive ripening of natto during storage.

[0096] Further, the sealing bag is provided with a large number of fine through-holes, and the through-holes function as tearing starting points, so that the natto can be easily torn when opened.

Further, since the sealed bag is made of the above-described highly moisture-permeable film alone, it is composed of a plastic cup and a polyethylene lid having a needle hole or a container with a lid made of styrofoam like a conventional natto packaging material. The cost can be significantly reduced as compared to

Further, by forming the sealed bag into a pillow structure, that is, a tube structure, natto can be easily taken out after being opened and can be taken out without sticking the natto to the hand. In addition, a required amount of natto can be taken out.

Therefore, it is possible to provide a natto packaging sealed bag that can maintain the freshness of natto for a long period of time, can be easily torn, and is easy to handle.

According to the method for producing a sealed natto packaging bag according to the seventh aspect of the present invention, boiled soybeans and natto bacteria are stored in the packaging bag for high moisture permeability described in the fourth aspect, through the opening portion thereof. After the sealant films on the inner surface of the opening are sealed by heat sealing, the highly moisture-permeable packaging bag is 100 g / m ² · 24 hr at 40 ° C. and 90% RH.
(More preferably 500 g / m ² · 24 hr or more)
The fermentation of the boiled soybean in the presence of the Bacillus natto in the state of the bag (sealed bag) because it has a high water vapor permeation rate and can control the permeation amount of gas such as oxygen The water vapor generated during the aging and the water vapor generated during the aging can escape to the outside of the bag very quickly. For this reason,
Fermentation and maturation from the boiled soybeans stored in the sealed bag can be continuously performed. As a result, a complicated operation of heat-sealing the sealant film to the cup before aging such as when a lid made of a sealant film having a plastic cup and a needle hole is used as a packaging material as in the related art, and with a lid The complicated operation of attaching the lid to the container before maturation as in the case of using a rectangular container made of Styrofoam can be omitted, and the productivity of the natto packaging sealed bag can be improved. In addition, since the sealed bag is made from the above-described highly moisture-permeable film alone, the number of parts can be reduced as compared with the conventional natto packaging material, and the cost can be reduced.

[0101]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail.

Comparative Example 1 A 20 μm thick OPP film was coated with a 2 μm thick urethane-based adhesive (trade name: RU-40 manufactured by Rock Paint Co., Ltd.) and dried. An aqueous solution of PVA) was applied and dried to form a 3 μm-thick PVA film to form a long laminated film.

Example 1 A long laminated film similar to that of Comparative Example 1 was subjected to a porous treatment using the above-described porous film production apparatus to form a V-shaped cross section, and the average opening diameter on the large opening side. A highly moisture-permeable film was produced in which a large number of through holes having a diameter of 50 μm and an average opening diameter of 5 μm on the small opening side were formed at a density of 100 / cm ² .

Comparative Example 2 A 2 μm-thick urethane-based adhesive (trade name: RU-40, manufactured by Rock Paint Co., Ltd.) was applied to a 25 μm-thick PET film, and dried. An aqueous solution of PVA) was applied and dried to form a 3 μm-thick PVA film to form a long laminated film.

Example 2 A long laminated film similar to that of Comparative Example 2 was subjected to a porous treatment in the same manner as in Example 1 to produce a highly moisture-permeable film.

Comparative Example 3 A 2 μm-thick urethane-based adhesive (trade name: RU-40, manufactured by Rock Paint Co., Ltd.) was applied to a 25 μm-thick nylon film, and dried. An aqueous solution of PVA) was applied and dried to form a 3 μm-thick PVA film to form a long laminated film.

Example 3 A long laminated film similar to that of Comparative Example 3 was subjected to a porous treatment in the same manner as in Example 1 to produce a highly moisture-permeable film.

(Reference Examples 1 to 3) OPP film having a thickness of 20 μm, PET film having a thickness of 25 μm, and thickness 25
Each of the μm nylon films was subjected to a porous treatment in the same manner as in Example 1 to produce three porous films.

The oxygen permeability and water vapor permeability of the obtained highly moisture-permeable films of Examples 1 to 3, the laminated films of Comparative Examples 1 to 3 and the porous films of Reference Examples 1 to 3 were measured. The oxygen permeation amount is the product name of JASCO Corporation;
A sample having a diameter of 10 cm cut out from the gas barrier film using a gas palm was subjected to an oxygen concentration of 100% and 25%.
The measurement was performed under the condition of 5 ° C. and 5 kg / cm ² in a dry atmosphere. The amount of water vapor permeation is determined by the Swiss Dr. Lyssy
A 10 cm diameter sample cut out from the gas barrier film using L80-4000 model
It was measured under the conditions of 40 ° C. and 90% RH according to IS K7129A. The results are shown in Table 1 below.

[0110]

[Table 1]

As is clear from Table 1, Examples 1 to
The highly moisture permeable film of No. 3 has an appropriate amount of oxygen permeation and 2500-3500 at 40 ° C. and 90% RH.
g / m ² · 24 hr, indicating that the porous films of Reference Examples 1 to 3 have a surprisingly high water vapor transmission rate.

In particular, the porous film made of the nylon film of Reference Example 3 was 200 ° C. at 40 ° C. and 90% RH.
g / m ² · 24 hr, although the water vapor transmission rate is relatively high, the highly moisture-permeable film using a nylon film as the outer layer of the laminated film as in Example 3 of the present invention is 3
It can be seen that the water vapor permeation amount is significantly higher than that of a porous film composed of a single nylon film at 500 g / m ² · 24 hr. Further, the porous film made of the nylon film of Reference Example 3 has a variation in oxygen permeation amount, which makes it difficult to control the amount.

A 20 μm-thick OPP film, a 25 μm-thick PET film and a 25 μm-thick nylon film which were not subjected to a porous treatment were treated at 40 ° C. and 90% RH.
The amount of permeated water vapor is 10 g / m ² · 24 h, respectively.
r, 10 g / m ² · 24 hr and 80 g / m ² · 24 hr.

Comparative Example 4 A 2 μm-thick urethane adhesive (trade name: RU-40, manufactured by Rock Paint Co.) was applied to a 20 μm-thick OPP film, dried, and further, polyvinyl alcohol ( An aqueous solution of PVA) is applied and dried to laminate a 3 μm-thick PVA film, and a 30 μm-thick low-density polyethylene (LDPE) film having a thickness of 2 μm is further laminated on the PVA film.
Urethane adhesive (Rock Paint Co., Ltd .: RU
-40) to form a long laminated film.

Example 4 The same long laminated film as in Comparative Example 4 was subjected to a porous treatment using the above-described porous film production apparatus, so that the cross-section was V-shaped and the average opening diameter on the large opening side was increased. A highly moisture-permeable film was produced in which a large number of through holes having a diameter of 50 μm and an average opening diameter of 5 μm on the small opening side were formed at a density of 100 / cm ² .

Comparative Example 5 A 2 μm-thick urethane-based adhesive (trade name: RU-40 manufactured by Rock Paint Co., Ltd.) was applied to a 25 μm-thick PET film, and dried. An aqueous solution of PVA) is applied and dried to laminate a 3 μm-thick PVA film, and a 30 μm-thick low-density polyethylene (LDPE) film having a thickness of 2 μm is further laminated on the PVA film.
Urethane adhesive (Rock Paint Co., Ltd .: RU
-40) to form a long laminated film.

Example 5 A long laminated film similar to that of Comparative Example 5 was subjected to a porous treatment in the same manner as in Example 4 to produce a highly moisture-permeable film.

Comparative Example 6 A 2 μm-thick urethane-based adhesive (trade name: RU-40 manufactured by Rock Paint Co., Ltd.) was applied to a 25 μm-thick nylon film, and dried. An aqueous solution of PVA) is applied and dried to laminate a PVA film having a thickness of 3 μm.
Low-density polyethylene (LDPE) film with a thickness of 2μ
m urethane-based adhesive (trade name: R, manufactured by Rock Paint Co., Ltd.)
U-40) to produce a long laminated film.

Example 6 A long laminated film similar to that of Comparative Example 6 was subjected to a porous treatment in the same manner as in Example 4 to produce a highly moisture-permeable film.

Reference Example 4 A 30 μm-thick LDPE film was subjected to a porous treatment in the same manner as in Example 4 to produce a porous film.

The oxygen permeability and water vapor permeability of the obtained highly moisture-permeable films of Examples 4 to 6, the laminated films of Comparative Examples 4 to 6 and the porous film of Reference 4 were measured in the same manner as in Example 1. did. The results are shown in Table 2 below.
Shown in Table 2 also shows the oxygen permeation amount and water vapor permeation amount of the porous films of Reference Examples 1 to 3 described above.

[0122]

[Table 2]

As apparent from Table 2 above, Examples 4 to
6 that the highly moisture-permeable film has an appropriate oxygen permeability
500g to 2500g at 40 ° C and 90% RH
/ M ^Two・ 24 hrs compared to the porous films of Reference Examples 1 to 3
It can be seen that all have a surprisingly high water vapor transmission rate.

In particular, the porous film made of the nylon film of Reference Example 3 was 200 ° C. at 40 ° C. and 90% RH.
g / m ² · 24 hr, but having a relatively high water vapor permeation rate, as in Example 6 of the present invention.
A highly moisture-permeable film having a base film of a three-layer laminated film of PVA / LDPE is 2500 g / m ² · 24 h
It can be seen that it has a significantly higher water vapor transmission rate than the porous film consisting of r and the nylon film alone.

(Example 7) A highly moisture-permeable packaging bag 21 having a pillow-type structure shown in Fig. 3 was prepared using the highly moisture-permeable film having the film structure of the nylon film and the polyvinyl alcohol film of Example 3 described above. As shown in FIG. 7, the raw shiitake mushroom 52 was housed in the bag 21 through the opened portion thereof, and the PVA films on the inner surface of the opened portion were heat-sealed to produce a sealed bag 51 for shiitake mushroom packaging.

This sealed bag of Shiitake mushrooms was sealed at 25 ° C. and 50% RH.
And left open for 7 days, then opened and visually inspected for the condition of the raw shiitake mushrooms.

As a result, no decay of the raw shiitake mushroom caused by the accumulation of water vapor on the inner surface of the bag and the formation of dew was observed, and it was confirmed that the fresh mushroom had almost the same freshness as when stored in the bag.

Further, the sealed bag of Shiitake mushroom could be easily torn along the width direction when opened.

Example 8 Using the highly moisture permeable film having the film structure of the OPP film, polyvinyl alcohol film and LDPE film of Example 4 described above, FIG.
A pillow-type highly permeable packing bag 31 having a pillow structure shown in FIG. 1 was prepared, and boiled soybeans and natto bacteria were stored in the bag 31.
The sealant films located on the inner surface of the opening of the bag were sealed by heat sealing. Next, this sealed bag is
The mixture was fermented in an atmosphere of 90 ° C. and 90% RH for 20 hours, and the temperature was controlled at about 50 ° C. in the latter half of the fermentation. Thereafter, by aging at 4 ° C. for one day, a natto packaging sealed bag 61 in which natto 62 shown in FIG. 8 was sealed was produced.

This natto packaging sealed bag was left in a refrigerator (4 ° C.) for 7 days, and then opened to visually inspect the state of natto.

As a result, no rot of natto caused by the accumulation of water vapor on the inner surface of the bag was observed, and it was confirmed that the natto had almost the same freshness as when stored in the bag.

Further, the natto packaging sealed bag could be easily torn along the width direction when opened, and the natto could be easily taken out of the bag without the natto sticking to the hand.

[0133]

As described in detail above, according to the present invention, the amount of permeation of a gas such as oxygen can be appropriately controlled, and
° C., water vapor permeability of at 90% RH is 100g / m ² · ²
A highly moisture-permeable film having excellent water vapor permeability of 4 hours or more can be provided.

According to the present invention, the amount of permeation of gas such as oxygen can be appropriately controlled, and the amount of water vapor permeated at 40 ° C. and 90% RH is 100 g / m ² · 24 hr or more. It is possible to provide a highly moisture-permeable packaging bag which can be easily teared.

According to the present invention, the amount of permeation of gas such as oxygen can be appropriately controlled, and the amount of water vapor permeated at 40 ° C. and 90% RH is 100 g / m ² · 24 hr or more. It is possible to provide a low-cost mushroom packaging sealed bag which is provided with a bag having the mushroom and can keep the freshness of the mushroom stored in the bag for a long period of time and can be easily torn.

According to the present invention, the amount of permeation of gas such as oxygen can be appropriately controlled, and the amount of water vapor permeated at 40 ° C. and 90% RH is 500 g / m ² · 24 hr or more. Provided is a natto packaging sealed bag that has a bag having the natto stored therein, can maintain the freshness of natto for a long period of time, and can easily take out natto with a simple structure that can be easily torn. be able to.

According to the present invention, the amount of permeation of gas such as oxygen can be appropriately controlled, and the amount of water vapor permeated at 40 ° C. and 90% RH is 100 g / m ² · 24 hr or more. The present invention can provide a method for producing a sealed natto packaging bag capable of continuously carrying out fermentation and ripening after boiled soybeans and natto bacteria are stored and sealed in the bag.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a highly moisture-permeable film according to the present invention.

FIG. 2 is a sectional view showing another highly moisture-permeable film according to the present invention.

FIG. 3 is a front view showing a highly moisture-permeable packaging bag according to the present invention.

FIG. 4 is a sectional view of an essential part of the bag of FIG. 3;

FIG. 5 is a front view showing another highly moisture-permeable packaging bag according to the present invention.

FIG. 6 is a sectional view of an essential part of the bag of FIG. 5;

FIG. 7 is a perspective view showing a mushroom packaging sealed bag according to the present invention.

FIG. 8 is a perspective view showing a natto packaging sealed bag according to the present invention.

[Explanation of symbols]

1,11,26,35 ... rigid organic polymer film, 2,12,27,36 ... water-soluble organic polymer film, 3,15,27,39 ... laminated film, 4,16,28,40 ... Through holes, 13, 37: sealant film, 22, 32: highly moisture-permeable film. 21, 31: high moisture-permeable packaging bag, 51: mushroom packaging sealed bag, 52: mushroom (shiitake), 61: natto packaging sealed bag, 62: natto.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 30/02 B65D 30/02 33/01 33/01 81/24 81/24 D 81/26 81/26 C85 / 50 85/50 A F term (reference) 3E035 AA12 AA14 BA08 BB02 BC02 BD03 CA07 3E064 AA05 AA06 AA08 BA40 BB03 BC06 EA18 FA01 GA02 HD02 HD08 HE01 HN05 3E067 AA11 AB01 AB11 AC03 BA12A BB14 FA03B03A03 GD01 3E075 BA42 BB03 CA02 DD13 DD42 DD44 GA04 4F100 AK01A AK01B AK01C AK07 AK21 AK51G BA02 BA03 BA10A BA10C BA15 DA01 DC11 EJ33 EJ37 GB17 GB23 JB09B JD04 JK01A JK03 JL12C YY00

Claims (10)

[Claims] 1. A laminated film including a rigid organic polymer film and a water-soluble organic polymer film, and a large number of fine through holes formed in the thickness direction of the laminated film. A highly moisture-permeable film characterized by the following. 2. A laminated film including a rigid organic polymer film, a sealant film, and a water-soluble organic polymer film, wherein the water-soluble organic polymer film is interposed in the middle, and in a thickness direction of the laminated film. A highly moisture-permeable film, comprising: a large number of fine through-holes formed therethrough. 3. The method according to claim 1, wherein the plurality of fine through-holes are 0.5 to 1
The highly moisture-permeable film according to claim 1, wherein the film has an average opening diameter of 00 μm and is formed at a density of 500 / cm ² or more over the thickness direction of the laminated film. 4. The highly moisture-permeable film according to claim 1, wherein the water vapor transmission rate at 40 ° C. and 90% RH is 100 g / m ² · 24 hr or more. 5. A multi-layered film comprising a rigid organic polymer film and a water-soluble organic polymer film, and a large number of fine through-holes formed in a thickness direction of the laminated film. A highly moisture-permeable packaging bag comprising a moisture-permeable film. 6. A laminated film including a rigid organic polymer film, a sealant film and a water-soluble organic polymer film, wherein the water-soluble organic polymer film is interposed therebetween and extends in the thickness direction of the laminated film. A highly moisture-permeable packaging bag, comprising a highly moisture-permeable film having a large number of fine through holes perforated. 7. A laminated film including a rigid organic polymer film and a water-soluble organic polymer film, and a large number of fine through-holes formed in the thickness direction of the laminated film. A mushroom packaging and sealing bag, wherein mushrooms are stored in an unsealed bag having an opening portion, and the water-soluble organic polymer films in the opening portion are sealed by heat sealing. 8. A laminated film including a rigid organic polymer film, a sealant film, and a water-soluble organic polymer film, wherein the water-soluble organic polymer film is interposed therebetween and extends in the thickness direction of the laminated film. Natto was stored in an unsealed bag having a high moisture-permeable film having a large number of fine through holes perforated and having an opening, and the sealant films in the opening were sealed by heat sealing. A natto packaging sealed bag, characterized in that: 9. The high-moisture permeable film has a temperature of 40.degree.
10. The sealed natto packaging bag according to claim 9, wherein the water vapor transmission rate at% RH is 500 g / m ² · 24 hr or more. 10. A laminated film including a rigid organic polymer film, a sealant film and a water-soluble organic polymer film, wherein the water-soluble organic polymer film is interposed therebetween and extends in the thickness direction of the laminated film. A step of storing boiled soybeans and Bacillus natto in an unsealed bag having a large number of fine through-holes perforated and having an unsealed portion, and sealing the sealant films of the unsealed portion with each other. A step of fermenting and aging the boiled soybeans in the presence of the Bacillus natto after sealing by heat sealing.