JPH05329947A - Rackaging film for keeping freshness of vegetable and fruit - Google Patents

Abstract

PURPOSE:To provide a packaging film for keeping of freshness in order to keep a gas composition in a system suitably by hermetically packaging vegetables and fruits. CONSTITUTION:In order to specify so that permeability of oxygen and carbon dioxide at 23 deg.C of the whole of a film becomes 1000-100000cc/mm<2>.24hrs.atm, micro pores of 100-300mum in mean diameter should be at a rate of 1000 pores/m<2> max. in the film, and the permeability of oxygen and carbon dioxide per each micro pore shall be 100-900cc/24hrs.atm. Thereby, MA packaging by hermetically packaging vegetables and fruits with film of every possible materials will be practicable, and decrease in freshness of vegetables and fruits can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a freshness-keeping packaging film for suppressing deterioration in freshness of fruits and vegetables such as flowers, fruits and vegetables. More specifically, the present invention relates to a freshness-keeping packaging film for hermetically packaging fruits and vegetables and maintaining an appropriate gas composition in the system.

[0002]

2. Description of the Related Art As one of methods for suppressing deterioration of freshness of fruits and vegetables, a method of changing atmospheric gas composition of fruits and vegetables is generally used, and is put to practical use as long-term storage of apples as CA (Controlled Atmosphere) storage. Has been done. In addition, the so-called MA, which keeps the inside of the package low in oxygen and high in carbon dioxide by using the film-sealed package and the breathing action of fruits and vegetables,
(Modified Atmosphere) Storage is also widely used. At this time, in order to maintain an appropriate gas composition in the packaging bag, it is indispensable to select a film having appropriate oxygen and carbon dioxide gas permeability according to the breathing amount of fruits and vegetables.

There are the following three conventional methods for controlling the oxygen and carbon dioxide gas permeability of the film. Selection of film material with appropriate gas permeability Adjusting gas permeability by changing film thickness Adjusting gas permeability by opening holes in the film utilizes oxygen and carbon dioxide gas permeability that is unique to the film material, Oxygen and carbon dioxide gas permeability are selected. For example, in the case of polyethylene, which is the most typical thermoplastic resin, the oxygen permeability at 23 ° C at a thickness of 30μ is
5000 to 8000cc / m ² · 24hrs · atm, and in the case of a biaxially oriented polypropylene film with the same thickness, the oxygen permeability at 23 ° C is 1000 to 3000cc / m ² · 24hrs · atm. It is possible to control oxygen and carbon dioxide gas permeability by changing the material.

[0004] utilizes the fact that the gas permeability of a film is inversely proportional to the thickness, and even a film of the same material can obtain a wide range of gas permeability by changing the film thickness. Is a technique in which fine holes are made in a film and the gas permeability is controlled by the size and number of the holes. 20 to 10 on film
Has holes with an average diameter of 0μ, 1 per square meter
A film having 0 to 1000 holes and having an oxygen permeability at 25 ° C. and 75% of not more than 200,000 cc / m ² · 24 hrs · atm is disclosed in JP-A-2-73831 and JP-A-2-85181. It is proposed in Japanese Patent Publication No.

[0005]

However, in the above-mentioned prior arts and techniques, there is a drawback in that the material and thickness of the film used are limited, and the printability, stiffness, strength, and sealability of the film material conventionally exist. At present, it is not practical because its sex is very limited. Further, in the above-mentioned method and method, in the case of a laminated film, the range of selection of oxygen permeability is further narrowed. Generally, the gas permeability suitable for MA packaging of fruits and vegetables is mostly in the range of 1000 to 100000 cc / m ² · 24 hrs · atm in terms of oxygen permeability at 23 ° C. On the other hand, in ordinary laminated films, packaging materials such as stretched polypropylene, polyamide, and polyethylene terephthalate, which have relatively low oxygen permeability, are often used as the base material, and the oxygen permeability of the laminated film composed of these is 1000cc at 23 ° C. / m ² · 24hrs · atm or less, which is not suitable as a MA packaging film for fruits and vegetables.

Also, in the case of a MA packaging film for fruits and vegetables having a very large respiration rate, such as green plum, broccoli, mushroom, etc., if the oxygen permeability of the film is insufficient, the oxygen concentration in the packaging bag will drop sharply, Respiratory disorder causes a strange odor
Loss of merchandise due to obstacles. In this case, the film
Oxygen permeability at 23 ℃ is usually 15000cc / m ² · 24hrs · atm
Although it may be necessary above, it is difficult to obtain this oxygen permeability by the above method and, even at 23 ℃ even ethylene-vinyl acetate copolymer film and polybutadiene film that is a film material with relatively high oxygen permeability Oxygen permeability of 15000cc / m ² · 24hrs
Since it is below atm, there is a risk of respiratory failure due to lack of oxygen in the packaging bag during high temperature distribution in summer.

On the other hand, the technique (1) is basically applicable to all kinds of packaging materials, and is far superior to the technique (1) in that the film material, the constitution, the presence or absence of printing, etc. are not selected. Is clear. However, in the methods proposed in JP-A-2-73831 and JP-A-2-85181, the average diameter is 20-100 μm.
Is. With this pore size, when the fruits and vegetables are put in and sealed, minute dusts coming from the fruits and vegetables easily block the pores, and it is difficult to accurately control oxygen and carbon dioxide gas permeability.
Further, various minute dusts such as dust and film pieces are also generated during the opening process, which also makes it difficult to accurately control the oxygen and carbon dioxide gas permeability by closing the hole portion.

Further, when the hole diameter is 100 μm or less, when printing is performed after opening, the fine holes are filled with the printing ink,
It also has the drawback of not exerting its effect. Opening is not always performed after lamination and printing.When printing or anti-fog processing is performed after opening, holes with a size of 100 μ or less will fill the holes and change the hole diameter, resulting in oxygen and carbon dioxide. It is impossible to control the gas permeability accurately. Further, in the current technology, an optical means such as a laser has to be used for the uniform opening having an average diameter of 100 μ or less, which has a drawback that the processing cost becomes high. In the case of a physical method, for example, in the case of opening with a heating needle, it is difficult to control the hole diameter to 100 μ or less, but it is advantageous in terms of cost.

It is an object of the present invention to solve the above-mentioned problems in the prior art and to provide a packaging film which does not reduce the freshness of fruits and vegetables.

[0010]

Means for Solving the Problems In order to achieve the above object, the inventors of the present invention have conducted extensive studies and as a result, found that the average diameter was 100 to
With 300μ micropores, the oxygen and carbon dioxide gas permeability of the film can be regulated by the micropore area and the number of micropores, and the fine dust generated from fruits and vegetables and the fine dust generated when opening can fine The inventors have found that it is possible to produce a film for freshness-keeping packaging for fruits and vegetables in which pores are not blocked, and have completed the present invention.

That is, according to the present invention, the entire film is 23 ° C.
Oxygen and carbon dioxide gas permeability of 1000 to 100000cc / m
^In order to regulate to ²・ 24hrs ・ atm, the film has micropores with an average diameter of 100-300μ at a rate of 1000 / m ² or less and the permeability of oxygen and carbon dioxide gas per micropore is 1
The main point is a film for freshness and packaging of fruits and vegetables, which is 00-900cc / 24hrs.atm.

The present invention will be described in detail below. The fruit and vegetables freshness-keeping packaging film of the present invention has an average diameter of the film.
It has 100-300μ micropores. The oxygen and carbon dioxide permeability of the film depends on the pore size and its number, that is, the micropore area,
According to the experiments conducted by the present inventors, the oxygen and carbon dioxide gas permeabilities per one micropore are 100 to 900 cc / 24 hrs.atm. This means that the permeation amounts of oxygen and carbon dioxide from the micropores are the same, and the permeation amount is proportional to the pore area. For example, it has been clarified by experiments by the present inventors that the oxygen and carbon dioxide gas permeation rate per micropore is about 100 cc / 24 hrs · atm when the micropore diameter is 100 μm. Therefore, the oxygen permeability of the film can be controlled by changing the number of holes per square meter.

In the present invention, the average diameter of the micropores is important, and when the average diameter exceeds 300 μ, the oxygen and carbon dioxide gas permeation rate per micropore exceeds 900 cc / 24 hrs.atm, which is suitable for MA storage of fruits and vegetables. It is difficult to control the oxygen and carbon dioxide permeability of a suitable film. If it is less than 100 μm, as described above, it is difficult to precisely control the oxygen and carbon dioxide gas permeabilities when the fruits and vegetables are sealed and microscopic dusts coming out from the fruits and vegetables are likely to close the holes. Further, various minute dusts such as dust and film pieces are also generated during the opening process, which also makes it difficult to accurately control the oxygen and carbon dioxide gas permeability by closing the hole portion.

If the hole diameter is less than 100 μm and the printing is performed after the opening, the printing ink fills the fine holes,
It also has the drawback of not exerting its effect. Opening is not always performed after lamination and printing.When printing or anti-fog processing is performed after opening, holes smaller than 100 μ will fill the holes and change the hole diameter. It is impossible to control the gas permeability accurately. Further, in the current technology, an optical means such as a laser has to be used for the uniform opening having an average diameter of less than 100 μ, which has a drawback that the processing cost becomes high. In the case of a physical method, for example, in the case of opening with a heating needle, it is difficult to control the hole diameter to 100 μ or less, but it is advantageous in terms of cost. Therefore, in the present invention, the average diameter of the micropores is 100 to 300.
μ is an essential element.

In the present invention, the shape of the hole is a circle or an ellipse depending on the processing method and the processing speed. Particularly in the case of a physical method, for example, when a heating needle is used, the contact time between the needle and the film becomes long, so that the shape tends to be an ellipse. Even in such a case, the same effect can be obtained if the holes have an area equivalent to a circle having an average diameter of 100 to 300 μm. That is, in the present invention, the fine holes do not necessarily have to be perfect circles.

As the material of the film, all commonly used polymer films can be used, or a laminated film can be used, and the present invention is not limited by the material of the film. It is more preferable that the innermost layer has a layer that can be heat-sealed at a low temperature because sealing can be easily performed. However, if the sealing is complete, a method such as a rubber band stopper may be used. Further, the film of the present invention does not necessarily need to be transparent, and printing, antifogging treatment and the like can be added if necessary. The openings can be formed before or after the steps such as printing and antifogging treatment.

As the method of opening, both physical means such as a heating needle and optical means such as a laser can be used. If the pore diameter is 100 to 300 μ, it is within a range in which the pores can be sufficiently opened even by using physical means, which is advantageous in terms of cost. Of course, it can be processed with a laser or the like, and in this case, more precise control of the hole diameter becomes possible.
The film for freshness and packaging for keeping fruits and vegetables of the present invention makes it possible to control oxygen and carbon dioxide gas permeation rates in single films and laminated films of all materials, and enables MA storage in which fruits and vegetables are stored in a low oxygen and high carbon dioxide state. Becomes

[0018]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0019]

Example 1 A single-sided heat-sealable biaxially oriented polypropylene film 30 μ (manufactured by Tokyo Cellophane Paper Co., Ltd.) was continuously heated with a heating needle so that the average diameter of the holes was 150 μ and the number of holes was 50 holes / m ^2. Was opened.

[0020]

Example 2 A single-sided heat-sealable biaxially oriented polypropylene film 30μ (manufactured by Tokyo Cellophane Paper Co., Ltd.) was continuously heated with a heating needle so that the average diameter of the holes was 150μ and the number of holes was 100 holes / m ^2. Was opened.

[0021]

Example 3 A biaxially stretched polypropylene film 30 μm (manufactured by Tokyo Cellophane Paper Co., Ltd.) capable of heat-sealing on one side was continuously heated with a heating needle so that the average diameter of the holes was 150 μm and the number of holes was 200 holes / m ^2. Was opened.

[0022]

Example 4 A single-sided heat-sealable biaxially oriented polypropylene film 30μ (manufactured by Tokyo Cellophane Paper Co., Ltd.) was continuously heated with a heating needle so that the average diameter of the holes was 150μ and the number of holes was 200 holes / m ^2. After that, a printing process was performed on the opening portion. [Comparative Example 1] A biaxially stretched polypropylene film 30 μm (manufactured by Tokyo Cellophane Paper Co., Ltd.) capable of heat-sealing on one side was continuously heated with a heating needle so that the average diameter of holes was 500 μm and the number of holes was 50 holes / m ^2. Was opened.

[Comparative Example 2] Biaxially oriented polypropylene film 30μ capable of heat sealing on one side (Tokyo Cellophane Paper
(Manufactured by Co., Ltd.) were continuously opened using a laser so that the average diameter of the holes was 50 μm and the number of holes was 250 holes / m ² . [Comparative Example 3] A single-sided heat-sealable biaxially oriented polypropylene film 30μ (manufactured by Tokyo Cellophane Paper Co., Ltd.) was continuously used with a laser so that the average diameter of the holes was 50μ and the number of holes was 500 holes / m ^2. Opened.

[Comparative Example 4] Biaxially oriented polypropylene film 30μ capable of heat sealing on one side (Tokyo Cellophane Paper
(Manufactured by Co., Ltd.) were continuously opened with a laser so that the average diameter of the holes was 50 μm and the number of holes was 1000 holes / m ² . [Comparative Example 5] A single-sided heat-sealable biaxially oriented polypropylene film 30μ (manufactured by Tokyo Cellophane Paper Co., Ltd.) was continuously used with a laser so that the average diameter of the holes was 50μ and the number of holes was 1000 / m ^2. The holes were opened, and then the holes were printed.

[Comparative Example 6] Biaxially oriented polypropylene film 30μ capable of heat sealing on one side (Tokyo Cellophane Paper
(Manufactured by Co., Ltd.) was used without being opened. [Test Example 1] Table 1 shows the results of measuring the oxygen and carbon dioxide gas permeabilities at 23 ° C. of the films of Examples 1 to 4 and Comparative Examples 1 to 6 of the present invention.

As is clear from Examples 1 to 3, the film of this example has a higher oxygen permeability than an unopened single film and is free from clogging due to dust or the like. The oxygen and carbon dioxide gas permeabilities can be freely defined by changing the number, and the oxygen and carbon dioxide gas permeabilities were proportional to the number of pores. Further, the gas permeability did not change even when printing was performed after opening.

On the other hand, in Comparative Example 1, the oxygen and carbon dioxide gas permeabilities were large because the pore size was too large, and the oxygen and carbon dioxide gas permeabilities were not suitable for the MA packaging film. Further, as is clear from Comparative Examples 2 to 5, when the pore size is 50 μ, the permeability of oxygen and carbon dioxide gas is low because part of the pores is blocked by dust or dust at the time of opening processing,
The variation was getting bigger. In addition, no proportional relationship was observed between the number of holes and the permeability of oxygen and carbon dioxide. When printing was further performed, some of the holes were filled with the printing ink, and therefore the oxygen and carbon dioxide gas permeabilities were further reduced after printing.

[0028]

[Table 1]

[Test Example 2] Example 2 and Comparative Example 1,
Create a pouch with inner dimensions of 200 x 150 mm using 4 and 6 films.
(Pouch surface area 0.06 m ² ), 200 g of shiitake mushrooms were sealed and packaged, and after storing at 20 ° C. for 5 days, the internal gas composition and the quality change of shiitake mushrooms were examined. The results are shown in Table 2.

As is clear from Table 2, in this embodiment, it is possible to maintain the optimum oxygen concentration in the pouch, which is effective in preventing browning and wilting of shiitake mushrooms, and yet, due to excessive hypoxia, an offensive odor. Never happened. On the other hand, in Comparative Example 1, browning proceeded because the oxygen concentration was high.
Further, in the film of Comparative Example 4, the pores were partly blocked by dust during packaging and minute scraps, and as in Comparative Example 6, the oxygen concentration was too low and an offensive odor was generated.

[0031]

[Table 2]

[Test Example 3] Example 1 and Comparative Example 1,
Create a pouch with inner dimensions of 300 x 400 mm using 4 and 6 films.
(Pouch surface area 0.24 m ² ) and 1 kg of cut lettuce were hermetically sealed and stored at 10 ° C. for 3 days, and then the internal gas composition and the change in quality of cut lettuce were examined. The results are shown in Table 3.

As is clear from Table 3, in this embodiment, it is possible to maintain the optimum oxygen concentration in the pouch, which is effective in preventing browning and wilting of cut lettuce, and due to excessive hypoxia. No offensive odor was generated. On the other hand, in Comparative Example 1, browning proceeded because the oxygen concentration was high. Further, in the film of Comparative Example 4, the holes were partly blocked by dust during packaging and minute cut lettuce pieces, and Comparative Example 6
Similar to the above, the offensive odor was generated because the oxygen concentration was too low.

[0034]

[Table 3]

[0035]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it is possible to perform MA packaging by hermetically sealing packaging of fruits and vegetables with a film of any material, and it is possible to suppress deterioration of freshness of fruits and vegetables for a long period of time. , Very useful in industry.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area B29L 7:00 4F

Claims (4)

[Claims] 1. A film for fresh and fresh packaging for keeping fruits and vegetables, which has micropores having an average diameter of 100 to 300 μm, and oxygen and carbon dioxide permeabilities of the film are defined by the micropore area and the number of micropores. 2. Oxygen and carbon dioxide gas permeability at 23 ° C. of the whole film having fine pores is 1000 to 100000 cc / m ² · 24 hr.
The film for freshness-keeping packaging for fruits and vegetables according to claim 1, which is s · atm. 3. The oxygen and carbon dioxide gas permeation rate per micropore is 100 to 900 cc / 24 hrs · atm.
The freshness-preserving packaging film for vegetables and fruits as described above. 4. The film for keeping and maintaining freshness of fruits and vegetables according to claim 1, 2 or 3, wherein the number of micropores is 1 to 1000 / m ² .