JP7314495B2 - Freshness-preserving packaging bag - Google Patents

Description

TECHNICAL FIELD The present invention relates to a freshness-preserving packaging bag for fruits and vegetables.

In recent years, as a packaging material for fruits and vegetables, a packaging material has been proposed in which the gas permeability is controlled in order to keep the freshness of fruits and vegetables for a long period of time (see Patent Document 1).

However, in the packaging material disclosed in Patent Document 1, a certain amount of oxygen and moisture is present in the packaging material in consideration of the respiration of fruits and vegetables in order to maintain the freshness of fruits and vegetables.

In addition, in order to suppress the growth of mold while maintaining the respiration of fruits and vegetables, a packaging material has been proposed in which metal ions such as silver as an antibacterial agent are kneaded into a film with controlled gas permeability. (See Patent Document 2). However, such an antibacterial agent can exhibit antibacterial properties only in the part that contacts the film, and there is a possibility that the part that does not contact the film surface will be spoiled by mold.

In order to prevent such a phenomenon, it is necessary to use a volatile antibacterial agent and spread the antibacterial agent throughout the space inside the bag. Therefore, a packaging material has been proposed in which a gas permeability-controlled film contains a volatile antibacterial agent (see Patent Document 3). However, using a gas-permeable film means that even volatile antibacterial agents can permeate easily, and the antibacterial effect does not last long, so mold eventually grows.

In order to deal with this problem, packaging materials that use a volatile antibacterial agent and have reduced gas permeability have been proposed (see Patent Documents 4 and 5). In these proposals, by suppressing gas permeability, the antibacterial agent is suppressed from volatilizing out of the bag, and the sustainability of the effect is maintained.
However, no mention is made of the respiration of fruits and vegetables, and it is unclear whether the proposed amount of gas permeation is appropriate from the viewpoint of respiration of fruits and vegetables.

JP 2014-172632 A JP-A-6-105650 JP 2017-124841 A JP 2018-35111 A JP 2010-57382 A

In view of the above problems, an object of the present invention is to provide a freshness-preserving packaging bag for fruits and vegetables that can exhibit sufficient spatial antibacterial effects for a long period of time while controlling the respiration of fruits and vegetables.

In order to solve the above problems, the present invention proposes the following configuration.
A first invention is a packaging bag made of at least two films, wherein at least one of the two films is an antibacterial film, the antibacterial film is formed by laminating a base material, an adhesive layer, and a heat-sealable resin layer, the adhesive layer contains an antibacterial agent selected from the group consisting of aldehydes or alcohol compounds having a boiling point of 130 to 260 ° C., and the amount of volatilization of the antibacterial agent when the antibacterial film is heated to 150 ° C. for 20 minutes is 0.1 to 1.5 g / m. ² , the freshness-preserving packaging bag.

A second invention is a freshness-preserving packaging bag, wherein one of the two films is an antibacterial film and the other is a gas-permeable film.

A third invention is a freshness-preserving packaging bag, wherein the gas permeable film has a water vapor permeation rate and an oxygen permeation rate of 20 g/m ² /atm/day or less and 2,000 to 15,000 cc/m ² /atm/day, respectively.

A fourth aspect of the invention is a freshness-preserving packaging bag, wherein the gas permeable film has an oxygen permeation rate of 4,500 to 9,000 cc/m ² /atm/day.

A fifth aspect of the present invention is a freshness-preserving packaging bag, wherein the heat-sealable resin layer has at least one layer made of a polyolefin resin.

A sixth aspect of the invention is a freshness-preserving packaging bag, wherein the polyolefin resin is a cyclic polyolefin resin.

A seventh invention is a freshness-preserving packaging bag, wherein the heat-sealable resin layer has a thickness of 20 μm or more and 50 μm or less.

An eighth invention is a freshness-preserving packaging bag characterized in that the antibacterial agent contains one or more selected from the group consisting of (E)-2-hexenal, hexanal, cinnamaldehyde, citral, decanal, 2-nonanol, eugenol, carvacrol, and linalool.

By adopting the above configuration, the freshness-preserving packaging bag of the present invention can exert a sufficient spatial antibacterial effect for a long time with the antibacterial film while controlling the respiration of fruits and vegetables with the gas permeable film.

It is a schematic sectional drawing which shows the packaging bag of this invention. 1 is a schematic cross-sectional view showing an antibacterial film of the present invention; FIG.

The packaging material of the present invention is a packaging bag used for packaging fruits and vegetables, and the packaging bag is formed by stacking at least two films and sealing the peripheral edges. At least one of the two films is an antibacterial film, and the antibacterial film is formed by laminating a base material, an adhesive layer, and a heat-sealable resin layer in order from the outside of the packaging bag, and the adhesive layer has a boiling point of 130 to 260 ° C. The antibacterial agent is selected from the group consisting of aldehydes or alcohol compounds, and the amount of volatilization of the antibacterial agent when the antibacterial film is heated to 150 ° C. for 20 minutes is 0.1 to 1.5 g / m ² .

Furthermore, it is desirable that the other film of the packaging bag is a gas-permeable film.
In FIG. 1, the schematic sectional drawing of the packaging bag of this invention is shown.
The packaging bag 4 shown in FIG. 1 is composed of an antibacterial film 1 and a gas permeable film 2, and is filled with a content 3. As shown in FIG.
Next, FIG. 2 shows a schematic cross-sectional view of the antibacterial film 1 contained in the packaging bag of the present invention. This antibacterial film 1 is formed by laminating a base material 10, an adhesive layer 20 and a heat-sealable resin layer 30 in this order from the outside of the packaging bag 4. As shown in FIG.

(Base material)
The substrate 10 shown in FIG. 2 is desirably a film having excellent mechanical strength and excellent heat resistance. In addition, it is desirable that the base material 10 be made of a material having low permeability to the antibacterial agent used, that is, to have a configuration that makes it difficult for the volatile components of the antibacterial agent to permeate to the outside of the packaging bag.

Non-limiting examples of materials for forming the substrate 10 include synthetic resins selected from the group consisting of polyethylene (PE), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polypropylene (PP), and polyamides (PA) such as Nylon. The base material 10 may be a single layer or may have a multi-layer laminated structure.
Further, the substrate 10 preferably has a film thickness of 10 μm to 50 μm. By having a film thickness within this range, good workability and handleability can be obtained. Optionally, the substrate 10 may contain any additives known in the art, such as plasticizers, antioxidants, colorants, fillers, UV absorbers, antistatic agents, antiblocking agents, flame retardants, thickeners, and the like.

(Thermal bonding resin layer)
The heat-sealable resin layer 30 shown in FIG. 2 uses a polyolefin-based resin because it requires excellent adhesiveness to the adherend when heated. Examples of polyolefin resins include resins selected from the group consisting of polyethylene (PE), polypropylene (PP), ethylene vinyl acetate copolymer (EVA), and cyclic olefin copolymer (COC).
A preferred polyolefinic resin is a cyclic olefin copolymer (COC). By using COC, it is possible to enhance the sustained release of the antibacterial drug. Also, the heat-sealable resin layer 30 may be a single layer or may have a laminated structure of multiple layers.

Furthermore, it is preferable that the heat-sealable resin layer 30 has a film thickness of 20 μm to 50 μm. By having a film thickness within the range described above, it is possible to obtain sustained release of the antibacterial agent, good processability, handleability, unsealability, and thermal adhesiveness. If the film thickness of the heat-sealing resin layer 30 is less than 20 μm, the antibacterial agent cannot be released in a controlled manner, and the effect cannot be sustained for a long period of time. On the other hand, if the thickness exceeds 50 μm, the permeability of the antibacterial agent becomes poor, and a sufficient antibacterial effect cannot be obtained. The heat-sealable resin layer 30 may optionally contain any additives known in the art, such as adhesion promoters, plasticizers, antioxidants, colorants, fillers, UV absorbers, antistatic agents, anti-blocking agents, flame retardants, thickeners, anti-fogging agents, and slip agents.

(adhesion layer)
Adhesive layer 20 of FIG. 2 includes an antimicrobial agent and an adhesive. The adhesive layer 20 has the function of storing and releasing the antibacterial agent and the function of bonding the base material 10 and the heat-sealing resin layer 30 together. Non-limiting examples of adhesives that can be used include polyester adhesives, polyurethane adhesives, polyether adhesives, acrylic adhesives, epoxy adhesives, ethylene-vinyl acetate adhesives, vinyl chloride adhesives, silicone adhesives, and rubber adhesives.

Adhesive layer 20 may include one or more antimicrobial agents. The antibacterial agent contained in the adhesive layer 20 is an alcohol or aldehyde compound with a boiling point of 130°C or higher and 260°C or lower. If the boiling point is less than 130° C., the volatility is too good and the effect cannot be maintained for a long time. On the other hand, if the boiling point exceeds 260° C., it becomes difficult to volatilize, making it impossible to obtain the necessary amount of the chemical to exhibit the effect.

Non-limiting examples of aldehyde or alcohol compounds that can be used are (E)-2-hexenal (boiling point 146° C.), hexanal (boiling point 131° C.), cinnamaldehyde (boiling point 252° C.), anisaldehyde (b. 01 ° C.), decanal (boiling point 208 ° C.), hydroxycitronellal (boiling point 241 ° C.), 2-nonanol (boiling point 198 ° C.), eugenol (boiling point 253 ° C.), carvacrol (boiling point 237 ° C.), linalool (boiling point 198 ° C.), 2-phenylethanol (boiling point 215 ° C.), 2-phenoxyethanol (boiling point 244.7 ° C.). Preferred aldehyde or alcohol compounds include (E)-2-hexenal, hexanal, cinnamaldehyde, citral, decanal, 2-nonanol, eugenol, carvacrol, and linalool.

The adhesive layer 20 preferably has a thickness of 1 μm to 10 μm. By having a film thickness within this range, the adhesion strength between the base material 10 and the heat-sealing resin layer 30 (hereinafter sometimes referred to as "laminating strength") is sufficiently increased, and delamination of the base material 10 and/or the heat-sealing resin layer 30 during use or distribution can be prevented. At the same time, workability in forming the adhesive layer 20 is improved.

More preferably, the adhesive layer 20 has a thickness of 2 μm to 7 μm. By having a film thickness within this range, it is possible to further increase the lamination strength, shorten the drying time when forming the adhesive layer 20, and prevent drying defects.

If desired, adhesive layer 20 may contain any additives known in the art, such as colorants, fillers, UV absorbers, thickeners, and the like.

(antibacterial film)
In the antibacterial film of the packaging bag of the present invention, the desired spatial antibacterial effect depends on the volatilization amount of the antibacterial agent. The antimicrobial film can achieve the desired spatial antimicrobial effect by volatilizing the antimicrobial agent at a volatilization amount of 0.1-1.5 g/m ² when heated to 150° C. for 20 minutes. If the volatilization amount is less than 0.1 g/m ² , it may not be possible to exhibit a sufficient spatial antibacterial effect. On the other hand, if the volatilization amount exceeds 1.5 g/m ² , the lamination strength becomes insufficient, which causes delamination.

The antibacterial film of the packaging bag of the present invention can be produced by applying a composition containing an adhesive and an antibacterial agent to the substrate 10 shown in FIG. The method of forming the heat-fusible resin layer 30 can be carried out by any technique known in the art, such as extrusion lamination of heat-fusible resin or dry lamination of heat-fusible film.

In addition, the antibacterial film of the packaging bag of the present invention may include an additional layer on the surface of the substrate 10 opposite to the adhesive layer 20, between the substrate 10 and the adhesive layer 20, between the adhesive layer 20 and the heat-sealable resin layer 30, or on the surface of the heat-sealable resin layer 30 opposite to the adhesive layer 2. Non-limiting examples of additional layers include color layers, light shielding layers, gas barrier layers, water vapor permeable layers, UV absorbing layers, fragrance retaining layers, heat shielding layers, and the like.

(Gas permeable film)
The gas permeable film 2 of FIG. 1 preferably has a water vapor permeation rate of 20 g/m ² /atm/day or less and an oxygen permeation rate of 2,000 to 15,000 cc/m ² /atm/day.
By having a gas permeation amount within this range, it is possible to suppress the wilting of fruits and vegetables and the growth of mold, and at the same time, it is possible to appropriately control the respiration of fruits and vegetables.
If the water vapor permeation amount of the gas permeable film 2 exceeds 20 g/m ² /atm/day, fruits and vegetables tend to wither due to transpiration. On the other hand, if the oxygen permeation amount is less than 2,000 cc/m ² /atm/day, it will be in an extremely low oxygen state, which will cause deterioration in quality. If the oxygen permeation amount exceeds 15,000 cc/m ² /atm/day, fruits and vegetables will be in a state where they can breathe sufficiently, and deterioration will be accelerated. Furthermore, since the permeation amount of the antibacterial agent also increases, it becomes difficult to maintain the spatial antibacterial effect for a long time.

More preferably, the oxygen permeation amount is 4,500 to 9,000 cc/m ² /atm/day. Having an oxygen permeation amount within this range makes it possible to more appropriately control the respiration of fruits and vegetables, and to maintain the freshness of fruits and vegetables for a longer period of time.

Moreover, the gas permeable film of the packaging bag of the present invention can be formed using any material known in the art, such as PE, PET, PEN, PP, and PA, provided that it can be adhered by the heated heat-sealable resin layer 30 as long as it has the gas permeability described above.

A known technique may be used to control the amount of oxygen permeation and the amount of water vapor permeation of the gas permeable film. For example, as shown in Examples below, a method of forming fine holes in the base film and controlling the area density (opening ratio) of the holes may be used, or a method of changing the material of the gas permeable film to a material having a desired oxygen permeation amount or water vapor permeation amount may be used.

The packaging bag of the present invention can be formed by heating the periphery of the antibacterial film and the gas permeable film with the heat-sealing resin layer 30 arranged inside and bonding them together. Alternatively, the two antibacterial films may be formed by heating and laminating the peripheral edges of the two antibacterial films with the heat-sealable resin layer 30 disposed on the inner side. The packaging bag may have any shape including rectangular, circular and triangular. Alternatively, a self-supporting packaging bag may be formed by attaching a bottom film to the bottom of the packaging bag.

Non-limiting examples of fruits and vegetables to be packaged using the packaging bag of the present invention include vegetables such as peppers, paprika, eggplants, cucumbers, broccoli, spinach, tomatoes, corn, green soybeans, burdock, carrots, and okra, and fruits such as grapes, strawberries, bananas, oranges, lemons, apples, and pears.

Examples and comparative examples of the packaging bag of the present invention are shown below.

(Example 1)
First, a coating composition was prepared containing a urethane adhesive and the antimicrobial agent cinnamaldehyde (boiling point 252°C). The resulting coating composition was applied to a substrate 10 made of PET (E5100 manufactured by Toyobo Co., Ltd.) having a film thickness of 12 μm and dried at a temperature of 80° C. to form an adhesive layer 20 . Finally, a PE/COC laminated film (M3400MP manufactured by DIC Corporation) having a thickness of 30 μm was adhered onto the adhesive layer 20 to form a heat-sealable resin layer 30 to obtain an antibacterial film.

Subsequently, a sample with an area of 2 cm ² was cut from the obtained antimicrobial film. Samples were introduced into 20 mL vials and heated to 150° C. for 20 minutes. 1 mL of the gas in the vial was sampled and analyzed with a gas chromatograph to determine the volatilization amount of cinnamaldehyde. The volatilization amount of cinnamaldehyde in the antibacterial film of this example was 0.5 g/m ² .

Next, a urethane adhesive was applied to an OPP film having a film thickness of 20 μm with openings at a constant ratio, dried at a temperature of 80° C., and then a PE film was laminated to obtain a gas permeable film 2. The water vapor permeation amount was measured according to JIS K7129, and the oxygen permeation amount was measured according to JIS K7126. The gas permeable film of this example had a water vapor permeation rate of 10 g/m ² /atm/day and an oxygen permeation rate of 6,000 cc/m ² /atm/day.

Next, one film was cut out from each of the obtained antibacterial film and gas permeable film, and the films were pasted so that the heat-sealable resin layers 30 faced each other to obtain a pouch having internal dimensions of 18 cm×18 cm. One paprika was placed in the obtained pouch and stored in a constant temperature bath at 10°C for 30 days.
After that, the case where no fungal growth was visually observed was evaluated as "○", the case where mold growth was visually observed on ⅓ or less of the surface area was evaluated as "△", and the case where mold growth was visually observed over a wider area than ⅓ of the surface area was evaluated as "×".

Additionally, the appearance of the packaged paprika was evaluated. "○" when there is no appearance abnormality such as withering or discoloration, [△] when appearance abnormality such as withering or discoloration is observed in 1/3 or less of the surface area, and when appearance abnormality such as wilting or discoloration is observed in a wider area than 1/3 of the surface area.

A sample having a width of 15 mm and a length of 10 cm was then cut from the produced antimicrobial film. A T-shaped peel test between the base material 10 and the heat-sealable resin layer 30 was performed according to JIS K6854-3:1999, except that the tensile speed was changed to 300 mm/min, and the peel adhesive strength was measured.
The obtained peel adhesive strength was taken as the laminate strength of the antibacterial film of this example. A lamination strength of 1 N or more was evaluated as "○", a lamination strength of 0.5 N or more and less than 1 N was evaluated as "Δ", and a lamination strength of less than 0.5 N was evaluated as "x".

The numerical values and evaluation results of the obtained packaging bags are shown in Table 1 below.

(Example 2)
The procedure of Example 1 was repeated except that the oxygen permeation rate of gas permeable film 2 was changed to 9,000 cc/m ² /atm/day. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 3)
The procedure of Example 1 was repeated except that the water vapor transmission rate of the gas permeable film 2 was changed to 20 g/m ² /atm/day. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 4)
The procedure of Example 1 was repeated except that the heat-sealable resin layer 30 was changed to a PE film (LL-XMTD manufactured by Futamura Chemical Co., Ltd.). Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 5)
The procedure of Example 1 was repeated except that the amount of cinnamaldehyde used was changed. The resulting antimicrobial film exhibited a volatilization rate of 1.5 g/ ^m2 . Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 6)
The procedure of Example 1 was repeated except that the amount of cinnamaldehyde used was changed. The resulting antimicrobial film exhibited a volatilization amount of 0.1 g/ ^m2 . Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 7)
The procedure of Example 1 was repeated except that the heat-sealable resin layer 30 was changed to a PE film (LL-XMTD manufactured by Futamura Chemical Co., Ltd.) and the film thickness was changed to 50 μm. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 8)
The procedure of Example 1 was repeated except that the heat-sealable resin layer 30 was changed to a PE film (LL-XMTN manufactured by Futamura Chemical Co., Ltd.) and the film thickness was changed to 20 μm. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 9)
The procedure of Example 1 was repeated except that the oxygen transmission rate of gas permeable film 2 was changed to 4,500 cc/m ² /atm/day. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 10)
The procedure of Example 1 was repeated except that the heat-sealable resin layer 30 was changed to a COC film (Coxec ME-1 manufactured by Kurashiki Boseki Co., Ltd.) and the water vapor excess amount of the gas permeable film 2 was changed to 1.0 g/m ² /atm/day. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 11)
The procedure of Example 1 was repeated except that the heat-sealable resin layer 30 was changed to a PE film (LL-XMTD manufactured by Futamura Chemical Co., Ltd.) and that the pouch was obtained only with the antibacterial film 1 without using the gas permeable film 2. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 12)
The procedure of Example 1 was repeated except that the oxygen permeation rate of gas permeable film 2 was changed to 16,000 cc/m ² /atm/day. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 13)
The procedure of Example 1 was repeated except that the oxygen permeation rate of gas permeable film 2 was changed to 1,500 cc/m ² /atm/day. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 14)
The procedure of Example 1 was repeated except that the water vapor transmission rate of the gas permeable film 2 was changed to 30 g/m ² /atm/day. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 15)
The procedure of Example 1 was repeated except that the method for producing the antibacterial film was changed as follows and the film thickness of the heat-sealable resin layer 30 was changed to 60 μm. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.
First, a coating composition was prepared containing a urethane adhesive and cinnamaldehyde. The resulting coating composition was applied to a substrate 10 made of PET (E5100 manufactured by Toyobo Co., Ltd.) having a film thickness of 12 μm and dried at a temperature of 80° C. to form an adhesive layer 20 . Finally, a PE resin (LC600A manufactured by Japan Polyethylene Co., Ltd.) was laminated on the adhesive layer 20 by an extrusion lamination method to form a heat-sealable resin layer 30 to obtain an antibacterial film.

(Example 16)
The procedure of Example 1 was repeated except that the method for producing the antibacterial film was changed as follows and the film thickness of the heat-sealable resin layer 30 was changed to 10 μm. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.
First, a coating composition was prepared containing a urethane adhesive and cinnamaldehyde. The resulting coating composition was applied to a substrate 10 made of PET (E5100 manufactured by Toyobo Co., Ltd.) having a film thickness of 12 μm and dried at a temperature of 80° C. to form an adhesive layer 20 . Finally, a PE resin (LC600A manufactured by Japan Polyethylene Co., Ltd.) was laminated on the adhesive layer 20 by an extrusion lamination method to form a heat-sealable resin layer 30 to obtain an antibacterial film.

(Example 17)
The procedure of Example 1 was repeated except that a coating composition was prepared containing hexanal (boiling point 131° C.) instead of cinnamaldehyde. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Example 18)
The procedure of Example 1 was repeated except that a coating composition containing carvacrol (boiling point 237°C) was prepared instead of cinnamaldehyde. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Comparative example 1)
The procedure of Example 1 was repeated except that a coating composition was prepared containing hexyl cinnamaldehyde (boiling point 308°C) instead of cinnamaldehyde. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Comparative example 2)
The procedure of Example 1 was repeated except that a coating composition was prepared containing ethanol (boiling point 78° C.) instead of cinnamaldehyde. Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Comparative Example 3)
The procedure of Example 1 was repeated except that the amount of cinnamaldehyde used was changed. The obtained antimicrobial film showed a volatilization amount of 0.01 g/m ² . Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

(Comparative Example 4)
The procedure of Example 1 was repeated except that the amount of cinnamaldehyde used was changed. The resulting antimicrobial film exhibited a volatilization amount of 2.0 g/m ² . Table 1 shows the numerical values and evaluation results of the obtained packaging bags.

As can be seen from Table 1, all of Examples 1 to 18 had sufficient lamination strength, and both the antifungal evaluation and the appearance evaluation were good.
On the other hand, in Comparative Example 1, when an aldehyde compound having a boiling point of over 260°C (boiling point of 308°C) was used as an antibacterial agent, the amount of the antibacterial agent that volatilized and permeated the heat-sealable resin layer was too small, resulting in an antifungal property not being obtained.
Moreover, in Comparative Example 2, when an alcohol compound having a boiling point of less than 130° C. was used as an antibacterial agent, the antifungal property was not obtained for a long time because of the lack of sustained release property.
Furthermore, in Comparative Example 3, the volatilization amount was too small and the chemical amount was not sufficient, so it was found that the antifungal property could not be obtained. In Comparative Example 4, on the contrary, when the volatilization amount was too large, the content of the antibacterial agent in the adhesive layer increased, and it was found that the laminate strength decreased.

Summarizing the above results, it was clarified that by using an alcohol or aldehyde compound with a boiling point of 130° C. to 260° C. as an antibacterial agent, setting the volatilization amount to 0.1 to 1.5 g/m ² , and using an antibacterial film with a film thickness of 20 to 50 μm and a gas permeable film with a controlled gas permeability using a polyolefin resin for the heat-sealing resin layer 30, it is possible to achieve both excellent antifungal durability and appearance maintenance of fruits and vegetables.

REFERENCE SIGNS LIST 1 antibacterial film 2 gas permeable film 3 content 4 packaging bag 10 base material 20 adhesive layer 30 heat sealing resin layer

Claims (2)

A packaging bag made of two films, wherein one of the two films is an antibacterial film and the other is a gas permeable film, the antibacterial film is formed by laminating a base material, an adhesive layer, and a heat-sealable resin layer, the adhesive layer has a film thickness of 2 μm or more and 7 μm or less, the adhesive layer contains cinnamaldehyde as an antibacterial agent, the heat-sealable resin layer is a PE/COC laminated film , and the antibacterial property is obtained when the antibacterial film is heated to 150 ° C. for 20 minutes. The volatilization amount of the chemical is 0. 5 to 1. 0 g/m ² , and the gas permeable film has a water vapor permeation rate and an oxygen permeation rate of 20 g/m ² /atm/day or less and 4,500 to 9,000 cc/m ² /atm/day , respectively. 2. The freshness-preserving packaging bag according to claim 1, wherein said PE/COC laminated film has a thickness of 20 [mu]m or more and 50 [mu]m or less.

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