JPH05316940A - Container for retaining freshness of vegetables and fruits, method for retaining freshness and package for retaining freshness of vegetables and fruits - Google Patents

Abstract

PURPOSE:To obtain a preservation container suitable for retaining the freshness of vegetables and fruits by specifying an outer liner and an inner liner for nipping the corrugating medium of a corrugated box and sealing the ends of the corrugated board with a sealing tape. CONSTITUTION:A corrugated board having a resin coating layer 4 formed on the outside of an outer liner 1 and a moistureproofing resin coating layer 5 formed on the inside of an inner liner 3 on the inside of a corrugating medium 2 is used to form a container. The gaseous carbon dioxide permeability constant of the outer liner at 27 deg.C is regulated to >=5X10<-10>cm<3> (STP) cm/(cm<2>.sec.cmHg) and the moisture permeability of the inner liner is regulated to <=100g/m<2>.day at 27 deg.C. The ends of the corrugated cardboard on the outer surface of the container are sealed with a sealing tape and the ratio of the gaseous carbon dioxide permeability constant to the oxygen permeability constant of the container is regulated to >=1.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging container for retaining the freshness of fruits and vegetables using a packaging material made of a special corrugated cardboard, a preservation method, and a preserved fresh fruits and vegetables package.

[0002]

2. Description of the Related Art Various attempts have heretofore been made to maintain the freshness of fruits and vegetables. For example, you can wrap it in a non-breathable packaging material to prevent moisture from escaping, lower the storage temperature,
Various methods have been proposed, such as using an oxygen scavenger to suppress respiration and adsorbing ethylene gas to prevent ripening. For example, Japanese Examined Patent Publication No. 38-2757 describes that a high-pressure polyethylene film is used to wrap vegetables and store them in a refrigerator to prevent water from evaporating and ripening and storing them. Furthermore, permeability ratio of carbon dioxide and oxygen in JP 61-216640 _{(Qco 2} / Qo 2) is stored by controlling the packaging to breathe vegetables and fruits with a synthetic resin film 3-4 It is stated. However, even if such a film is used, a sufficient effect of maintaining freshness of fruits and vegetables cannot be obtained. Further, Japanese Patent Application Laid-Open No. 1-317354 describes a method in which the inside of a corrugated board box is stored in a storage gas composition and then cooled and stored. However, the corrugated board is ineffective because it communicates with the outside. Japanese Unexamined Patent Publication (Kokai) No. 2-233381 discloses a box in which the permeability of oxygen and carbon dioxide of corrugated cardboard is adjusted, but the composition of the atmosphere gas is a necessary composition by simply limiting the permeability of both gases. Because it does not become
After all it was not effective.

[0003]

The problem with the prior art is that the basic problem of the loss of freshness of fruits and vegetables has not been fully elucidated, so the problem of preservation of freshness could not be solved to a satisfactory degree. ..

According to the research conducted by the present inventors, fruits and vegetables show a life reaction even during storage, and when they breathe, plant hormones and enzymes also act. Therefore, for example, if ethylene gas is present in the storage atmosphere, aging hormone is actively secreted and aging is promoted. In addition, the composition of the storage atmosphere changes due to the respiration of fruits and vegetables, and when the oxygen content becomes too low and the carbon dioxide gas increases, ateless breathing occurs and alcohol fermentation progresses to produce aldehydes and ethanol, resulting in a decrease in freshness. However, on the other hand, when there is a lot of oxygen, breathing is performed vigorously and maturation proceeds. Thus, the composition of the preservation atmosphere plays an important role in maintaining the freshness of fruits and vegetables, and not only the carbon dioxide gas but also the amount of oxygen must be controlled to an appropriate value.

Most fruits and vegetables are 80 to 95 in most crops.
%, The water content is high, and when they are left under low humidity, water evaporates more violently than tissues such as pericarp and leaves, and this water loss immediately causes wilting and decreases freshness.
Loss of 5% or more of water usually causes some change in appearance.

The present inventors have paid attention to such plant physiology and studied to adjust the composition of gas in the preservation atmosphere. As a result, in order to maintain the freshness of fruits and vegetables, the evaporation of water is suppressed, the existing amount of oxygen in the storage atmosphere is adjusted to be in the range of 1 to 16%, preferably 2 to 12%. It has been clarified that it is necessary to reduce the existing amount of carbon dioxide gas in (1) to as low as possible and set it in the range of 0 to 20%, preferably 2 to 15%.

The inventor of the present invention has a carbon dioxide permeability coefficient Pco _{2 at} 27 ° C. of 15 × 10 ⁻¹⁰ cm ³ (STP) cm / cm ₂ as a packaging material forming the above-mentioned storage atmosphere.
(Cm ² · s · cmHg) or more, the ratio of the carbon dioxide gas permeability coefficient Pco ₂ to the oxygen permeability coefficient Po ₂ is 4.2 or more, and the water vapor permeability coefficient PH ₂ O is 80 × 10 ⁻⁹ cm.
The invention of a freshness-keeping packaging material for fruits and vegetables, which is made of a synthetic resin film of ³ (STP) cm / (cm ² · s · cmHg) or less, has been completed. This is the invention of Japanese Patent Application No. 2-103131. The present inventor has conducted further research and succeeded in improving a container made of widely used corrugated cardboard so as to have a fresh preservation effect of fruits and vegetables.

[0008]

[Means for Solving the Problems] The composition of the preservation atmosphere is changed by the respiration of fruits and vegetables, and the composition moves in the direction of maintaining the equilibrium state and the equilibrium state is maintained. If this equilibrium does not cause atelectasis, there is little secretion of aging hormones, there is no acceleration of aging, and breathing is possible, but the freshness of fruits and vegetables is maintained for a long time. In other words, carbon dioxide gas generated by breathing in the preservation atmosphere is released to the outside as much as possible, and appropriate amount of oxygen is introduced into the preservation atmosphere from the outside to balance the preservation atmosphere within the above range, thereby making the fruits and vegetables dormant. To maintain freshness. The present inventors have conducted various researches in order to create such a state,
The present invention has been completed by improving the packaging material based on the new finding that fruits and vegetables cannot be put into a dormant state unless the packaging material is improved.

In the present invention, first, the carbon dioxide permeability coefficient Pco2 of the outer liner is 5
× 10 ⁻¹⁰ cm ³ (STP) cm / (cm ² · s · c
mHg) or more, the storage atmosphere cannot be satisfied no matter how the other conditions are changed, and the ratio of the carbon dioxide gas permeability coefficient Pco ₂ to the oxygen permeability coefficient Po ₂ of the container is 1.5 or more. is necessary. 1.
When it is 5 or less, the concentration of carbon dioxide and oxygen cannot be sufficiently controlled and the fruits and vegetables cannot be kept in a dormant state, and the moisture permeability of the inner liner is 100 g / m ² · da.
If it is not less than y, the amount of water released to the outside of the packaging material will increase, and the water evaporation of the fruits and vegetables inside the packaging will become violent and wither, so that the freshness of the fruits and vegetables cannot be maintained, and the evaporated water will be transferred to the liner and core. The box strength was reduced. Therefore, the present invention provides a synergistic effect of fresh preservation of fruits and vegetables by combining all of the above conditions with each other.

The present invention relates to "(1) (A) Carbon dioxide permeation coefficient Pc at 27 ° C.
o ₂ is 5 × 10 ⁻¹⁰ cm ³ (STP) cm / (cm
^An outer liner of ² · s · cmHg) or more, and (B)
100 g / m ² · day at core and (C) moisture permeability at 27 ° C
The ratio Pco ₂ / of the carbon dioxide permeation coefficient and the oxygen permeation coefficient of the container, which is composed of corrugated cardboard consisting of the following inner liner, and the end of the corrugated cardboard exposed on the outer surface of the container is substantially closed by a sealing tape. A container for storing fresh vegetables and fruits having a Po ₂ of 1.5 or more. (2) Inner liner is 100g / m ² · day at 27 ℃
The fresh vegetables and fruits storage container according to item 1, which is composed of a liner material having the following moisture permeability. (3) The inner liner has a water vapor transmission rate of 100 at 27 ° C.
3. The fresh container for fresh fruits and vegetables according to item 1 or 2, which is composed of a liner material having a resin layer of g / m ² · day or less as the innermost layer. (4) The carbon dioxide permeability coefficient of the outer liner at 27 ° C. is 5 × 10 ⁻¹⁰ cm ³ (STP) cm / (cm ² ·
A container for storing fresh vegetables and fruits according to any one of items 1 to 3, which is composed of a liner material having a resin coating of s · cmHg) or more as an outermost layer. (5) Sealing with sealing tape completely seals the exposed edges of the corrugated cardboard paper at the bottom, lid and corners, and seals the exposed edges of the side bonding parts, leaving the ventilation adjustment part. The container for fresh produce of fruits and vegetables according to any one of items 1 to 4, which is a sealed container. (6) (A) Carbon dioxide permeability coefficient Pco at 27 ° C
₂ is 5 × 10 ⁻¹⁰ cm ³ (STP) cm / (cm ²
・ Fruits and fruits are stored in a container made of corrugated paper consisting of an outer liner of s · cmHg) or more, (B) a core and (C) an inner liner of 100 g / m ² · day or less at a moisture permeability of 27 ° C. Then, seal the tape by sticking a sealing tape to the end of the corrugated paper exposed on the bottom of the container and the outer surface of the lid, and also seal the corner with the sealing tape. Is characterized in that a sealing tape is adhered to the container while leaving a ventilation control region, and the ratio Pco ₂ / Po ₂ of the carbon dioxide gas permeability coefficient and the oxygen permeability coefficient of the container is 1.5 or more. How to preserve fresh vegetables and fruits. (7) (A) Carbon dioxide permeability coefficient Pco at 27 ° C
₂ is 5 × 10 ⁻¹⁰ cm ³ (STP) cm / (cm ²
・ Fruits and fruits are stored in a container made of corrugated paper consisting of an outer liner of s · cmHg) or more, (B) a core and (C) an inner liner of 100 g / m ² · day or less at a moisture permeability of 27 ° C. Then, seal the tape by sticking a sealing tape to the end of the corrugated paper exposed on the bottom of the container and the outer surface of the lid, and also seal the corner with the sealing tape. Is characterized in that a sealing tape is adhered to the container while leaving a ventilation control region, and the ratio Pco ₂ / Po ₂ of the carbon dioxide gas permeability coefficient and the oxygen permeability coefficient of the container is 1.5 or more. Fruit and vegetable packaging. Regarding

[0011]

The corrugated board is composed of an outer liner, a core and an inner liner, and the core has a corrugated plate shape for absorbing an impact. This corrugated cardboard structure has a significant impact on the formation and maintenance of the preservation atmosphere, which is important for the fresh preservation of fruits and vegetables. Since the paper constituting the corrugated board has moisture permeability and air permeability, the storage atmosphere changes through the wall of the container.

Therefore, the present inventor sealed the end portion exposed to the outside and then applied various processing to the inner wall of the container, but the effect was not seen. As a result of further research, when a container is assembled with corrugated board, the groove of the corrugated plate of the end face that opens inside the corrugated board communicates with the wall of the outer liner. It was found that the atmosphere of storage changed due to communication through the groove in the center. This is a novel fact first revealed by the present inventor. As a result, no matter how the inner surface of the cardboard container is processed, the gas in the container escapes from the wall of the outer liner through the groove in the core, and the outside air enters the container through the opposite course. is there.

On the basis of this new finding, the present inventor has made it necessary to seal at least the end exposed to the outside in order to apply the corrugated container to fresh preservation of fruits and vegetables, and the outer liner of corrugated cardboard. Carbon dioxide permeability coefficient Pco ₂ at 5 ° C. is 5 × 10 ⁻¹⁰ cm ³ (STP)
The outer liner should be at least cm / (cm ² · s · cmHg), and it is absolutely necessary to set the ratio Pco ₂ / Po ₂ of the carbon dioxide permeability coefficient and the oxygen permeability coefficient of the sealed container to 1.5 or more. It was clarified that it was necessary to solve all problems.

Further, the inner liner releases water due to the daily reaction of fruits and vegetables, and absorption of this water not only lowers the strength of the container but also lowers the humidity in the container and promotes dehydration of the fruits and vegetables, so 100 g / 27 g at 27 ° C. It is desirable to use a liner material having a moisture permeability of m ² · day or less. For example,
The inner liner has a moisture permeability of 100 g / m ² at 27 ° C.
When the inner liner is formed by arranging the resin layer of day or less as the innermost layer, the inner liner satisfies the required performance. Further, the liner material may be resin-processed to have the above-mentioned moisture permeability. As the resin layer, a foamed resin coating layer may be used as well as a uniform coating.

The outer liner has a carbon dioxide gas permeability coefficient at 27 ° C. of 5 × 10 ⁻¹⁰ cm ³ (STP) cm /
An outer liner satisfying the required performance can be obtained by using a liner material having a resin coating of (cm ² · s · cmHg) or more arranged in the outermost layer. That is, if the outermost layer has the above-mentioned carbon dioxide permeability coefficient, the inflow and outflow of gas through the wall of the container is controlled, and if the end of the corrugated cardboard exposed to the outside is sealed with a sealing tape, the gas flow through the groove of the core is controlled. It is also possible to block the release inflow. In addition, it is possible to prevent the cardboard from absorbing moisture.

When the corrugated cardboard container is assembled, the upper and lower bottoms and the lid are usually sealed with adhesive tape, but the side surface is easily overlooked. However, the corrugated paper is adhered to the side surface, but the end face of the corrugated paper, which is the outer side, is exposed to the outside, and the gas similarly flows in and out from this surface. The present invention utilizes the corrugated cardboard end surface of the bonding part on this side surface, and can adjust the sealing of the end surface according to the fruits and vegetables stored in the container to adjust the change in the gas composition due to the respiration of the fruits and vegetables in the container. It has features.

In order to store fruits and vegetables using the container of the present invention, the fruits and vegetables are stored in a container, the end surface of the corrugated cardboard exposed to the outside is sealed with a sealing tape, and the corner portion where the sealing is apt to break is also sealed. A sealing tape is attached and sealed, and then the opening end of the corrugated cardboard on the side is sealed, leaving a ventilation control area if necessary, and the ratio of the carbon dioxide permeation coefficient to the oxygen permeation coefficient of the container Pco ₂ / By adjusting Po ₂ to 1.5 or more, the fruits and vegetables can be put into a dormant state and the fruits and vegetables can be preserved fresh for a long period of time. As will be described later in a comparative test, the ratio of the carbon dioxide permeability coefficient of the outer liner and the moisture permeability of the inner liner of the present invention and the ratio of the carbon dioxide permeability coefficient and the oxygen permeability coefficient of the container are not within the specific ranges of the present invention, respectively. Can't keep fresh

Next, the resin layer used in the present invention will be described.

As a characteristic of the outer liner, carbon dioxide permeability coefficient is 5 × 10 ⁻¹⁰ cm ³ (STP) cm / (cm
² · s · cmHg) or more, and the ratio Pco ₂ / Po ₂ of the carbon dioxide gas permeability coefficient and the oxygen permeability coefficient of the container is 1.5 or more. Therefore, the outer liner is made of a dense non-porous resin layer. Must be formed. As the resin layer satisfying these requirements, a resin having low density polyethylene or ethylene, α-olefin, vinyl acetate, acrylic acid, methacrylic acid or the like as a constituent component, that is, ethylene / α-olefin copolymer, ethylene Examples thereof include vinyl acetate copolymers, ethylene / acrylic acid copolymers, ethylene / methacrylic acid copolymers, and polystyrene and styrene / butadiene copolymers. Also, for the purpose of improving the permeability of these resins and the adhesion to the paper base material,
In some cases, the base resin may be graft-modified with silicone, maleic anhydride or the like before use.

The resin layer satisfying the requirements of the transmission characteristics of the present invention can be formed of a single synthetic resin, but it is composed of a plurality of synthetic resins because it is necessary to independently satisfy the above requirements of different characteristics. It is desirable to do. Typical examples of such synthetic resins include ethylene and α having 3 to 12 carbon atoms.
-Olefin copolymers such as ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-
4-methylpentene-1 copolymer, ethylene-octene-1 copolymer and the like can be mentioned, and it is preferable to use as a blend of at least two kinds selected from these resins. Also, a blend of ethylene, an α-olefin copolymer having 3 to 12 carbon atoms and low density polyethylene can be used. To obtain a particularly high carbon dioxide permeability coefficient, a low density ethylene-α-olefin copolymer having a relatively high α-olefin copolymerization ratio or a so-called ultra-low density ethylene-α having a high α-olefin copolymerization ratio is used. It is preferable to use an olefin copolymer as a main component, and in order to obtain a high selective permeation ratio, at least two kinds of resins composed of different monomers from the above resin group, for example, low density polyethylene and ethylene. -Hexene-1 copolymer, ethylene-butene-1
It is preferable to select and use a combination of a copolymer and an ethylene-hexene-1 copolymer.

As another method for obtaining a resin layer satisfying the requirements of the transmission characteristics of the present invention, the above-mentioned resin alone or a blend of a plurality of resins is used as a base polymer. United (EVA),
Ethylene-acrylic acid copolymers, ethylene copolymers such as ethylene-methylmethacrylate copolymers, ethylene or α-olefin-propylene-non-conjugated diene terpolymers, or styrene / butadiene block copolymers, styrene / isoprene blocks It is also possible to blend and use a resin such as a hydrogenated product of a copolymer. When these resins are used as a single resin, it is difficult to meet all the requirements of the permeability of the present invention, the laminating strength with paper is lowered, and cracks and cracks easily occur due to bending after laminating. 90:10 to 50: 5 relative to the above base polymer due to the tendency
It is necessary to use a blend ratio of 0.

Although the detailed reason why the selective permeation ratio of carbon dioxide gas and oxygen is increased by blending resins having different repeating units is not clear, the present inventors have found that molecular chains having different molecular motility are This is because there are regions that exist at different concentrations, and the permeability of both gases in that region changes depending on the molecular chain concentration.

As the characteristics of the inner liner, any resin may be used as long as the moisture permeability at 27 ° C. is 100 g / m ² · day or less, and among the resins used for the outer liner, ethylene may be used. A relatively high density resin containing as a main component is preferable, in addition to that, high density polyethylene, polypropylene, a copolymer resin containing propylene as a main component,
Further, a foam or the like is used. In this case, in order to more effectively prevent a decrease in box compressive strength due to moisture absorption, it is desirable to select a material and a thickness configuration in which the moisture permeability of the inner liner is smaller than that of the outer liner. The liner material having these resin layers is expected to have no cracks or cracks in the resin layer when processed as a corrugated cardboard box or to cause this kind of defects or delamination during use. It is important for ensuring container performance. In particular, cracks in the resin layer of the outer liner,
If delamination etc. occurs, the transmission coefficient ratio Pco ₂ / Po of the container
It becomes difficult to secure ₂ to 1.5 or more.

In these resin layers, phenol-based, organic sulfur-based, organic nitrogen-based, organic phosphorus-based antioxidants or heat stabilizers, metal soaps and other fatty acids are used in accordance with a formulation known per se. Lubricants such as esters and fatty acid derivatives, antifogging agents, antistatic agents, calcium carbonate, white carbon, titanium white, magnesium carbonate, magnesium silicate, carbon black, various clays, inorganic fillers such as natural or synthetic zeolites, or Other colorants and other compounding agents can be compounded in a compounding ratio known per se.

The thickness of the coating resin layer depends on the type of resin used and its physical strength, and the relationship of the properties of the paper used,
Depending on the case, it is necessary to properly set it in consideration of the type of fruits and vegetables to be packaged, the storage temperature, etc.
-60 μm, preferably 10-40 μm.

The melt index (MI) of the resin used in the present invention is not particularly limited.
Value is 0.1 to 30 g / 10 minutes, preferably 0.1 to 10
It is preferable to use a g / 10 min (according to JIS K6760) grade.

The resin layer of the present invention can be generally formed by extrusion lamination or lamination of resin films, sheets and the like. Further, for the purpose of improving the adhesiveness to paper and the surface characteristics of the resin coating layer, lamination using a multi-layer die or a multi-layer film formed by a multi-layer die in advance can be used. Further, it is preferable to install a predetermined resin coating layer on the outermost layer of each liner material, but as long as the permeation coefficient ratio Pco ₂ / Po ₂ of the container can be kept at 1.5 or more, the outermost layer is made of porous plastic. A layer made of a film or a paper having a relatively small basis weight or a synthetic paper may be provided by a method such as sand laminar or dry laminating. Furthermore, as a method other than the above, dry or wet lamination of a film formed in advance using an adhesive, or coating or impregnating a solution or dispersion paint on a liner base paper,
The resin layer can be formed by drying.

The paper used for the corrugated board of the present invention includes:
Paper made from cellulose pulp, for example, kraft paper, art paper, general printing paper or roll paper, thin paper, or so-called paperboard such as corrugated cardboard, manila balls, white paperboard such as white balls, etc. can be used. On the other hand, paper prepared by mixing synthetic resin fibers such as polyethylene can also be used.

It is preferable to print on the surface of the resin layer provided on the corrugated paper from the viewpoint of ensuring the beauty of the packaging container, and it is also possible to print on the paper prior to forming the resin layer on the paper. As the printing method, known printing methods such as normal gravure, flexo, and silk screen are possible.
Since the thickness of the printing layer is thin and it is not a continuous film, the influence on the permeability is extremely slight. When printing on the resin layer surface, from the viewpoint of increasing the ink adhesion and preventing scratch resistance,
After the resin coating or in the case of a film, it is effective to perform a treatment such as corona discharge treatment by a generally known method before coating.

When using the corrugated board of the present invention, known means effective for keeping the freshness of fruits and vegetables can be used together. For example, a gas adsorbent for ethylene, aldehyde, etc. generated from fruits and vegetables, a moisturizer or a hygroscopic agent for controlling water content, or an oxygen scavenger or a carbon dioxide gas scavenger may have a further effect on maintaining freshness. .. These auxiliaries are usually used in the form of another bag inside the corrugated cardboard of the present invention, but in some cases, they are coated on the liner of the present invention or impregnated with pulp or the like at the time of liner papermaking or It is also effective to use a method of mixing papers, or mixing them in a coating resin.

For sealing the corrugated cardboard box after the contents are filled, known seals such as I-seal and H-seal are used, and automatic machines, hand machines such as hand sealers are used. In the case of H-seal, it is necessary to devise to close the space at the corner of the cardboard box. If the corners are not completely sealed, it becomes difficult to maintain the permeation coefficient ratio Pco ₂ / Po ₂ of the container at 1.5 or more. Further, by changing the sealing width of the exposed end portion of the side surface bonded portion, it is possible to adjust the oxygen and carbon dioxide gas concentrations in the container to an appropriate range. This method is effective for contents having a relatively large respiratory volume. As the material of the tape used for sealing, those having gas permeability smaller than the value of the outer liner are suitable, but are not limited thereto, biaxially oriented polypropylene, vinyl chloride, biaxially oriented polyethylene terephthalate, biaxially oriented nylon, Suitable materials such as high density polyethylene, 20
˜80 μm, preferably 30-50 μm thickness, 20-8
A width of 0 mm is preferable. To store fruits and vegetables,
As the pressure-sensitive adhesive, one having water resistance is preferable, and one having cold resistance suitable for low temperature storage or distribution is preferable.

Next, a concrete description will be given with reference to examples.
In addition to those listed in the examples, fresh foods that can be preferably preserved fresh in the container of the present invention include citrus fruits such as CA, citrus fruits such as Sudachi, apples, sweet corn, leek, tomato, etc. Leaf vegetables such as gas and broccoli,
There are fresh shiitake mushrooms and cherry blossoms. For crops that require further low temperature storage, they can be used in combination with a cold storage agent, dry ice, or ice. As the effect of the present invention, in addition to the above, by using corrugated cardboard, depending on the respiratory volume of the contents,
The ratio of the surface area of the container to the internal volume can be freely set to optimize the gas composition in the container, especially for crops with a large respiration volume, a free space that is not the closest packing can be provided. It is possible to prevent pinholes in packaging materials, especially outer liners.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial sectional view of a wall of a corrugated board container according to the present invention. Reference numeral 1 denotes an outer liner, and the resin coating layer 4 is disposed on the outermost layer of the outer liner, so that the inflow and outflow of gas through the wall surface of the outer liner is controlled by the resin coating layer. Reference numeral 2 is a core, which is corrugated and has a communication groove 6 formed therein. An inner liner 3 is provided with the moisture-proof resin coating layer 5 as the innermost layer, so that movement of moisture through the resin layer is suppressed.

FIG. 2 is a perspective view of the assembled cardboard container 7 of the present invention. The lid and the exposed corrugated cardboard end portion of the bottom are sealed with a sealing tape 8. It is understood that the corner 9 is also sealed.

FIG. 3 shows the corrugated cardboard container of the present invention in which the corrugated cardboard end portion 10 exposed to the outside of the corrugated cardboard sticking portion on the side surface is sealed. In FIG. 3, the corrugated cardboard ends are all sealed, but a part may be left as the ventilation adjustment region.

FIG. 4 shows a cardboard container of a comparative example in which a resin coating layer 4 is provided inside the outer liner 1 and a resin coating layer 5 is provided on the inner core 3 of the inner liner 3.

Next, the evaluation of the permeation characteristics of gas and water vapor and the compressive strength of the cardboard container at 27 ° C. of various films and cardboard containers used in the following examples will be described.

(1) For measuring the gas permeability of the film, a mixed gas permeability measuring device (LYSSY GPM-20) using a commercially available gas chromatography as a detector.
0) was used. Carbon dioxide and air were allowed to flow to the inflow side of the film at a mixing ratio of 1: 4 at a normal pressure, and helium gas was used as the carrier gas on the exhaust side, and the gas composition on the exhaust side was measured moment by moment. Correct the number of gas counts with a calibration curve created in advance, determine the permeation amount at each time,
The gradient is obtained from those points by the least squares method, and the transmission coefficient Pco ₂ (cm ³ (STP) cm cm ⁻² · s is taken into consideration in consideration of the thickness of the film used and the effective area of the transmission cell.
⁻¹ · cmHg ⁻¹ ) was calculated. The measurement was carried out by keeping the permeation cell and chamber constant at 27 ° C.

(2) Water vapor permeability A commercially available water vapor permeability tester (LYSSY L
80-4000 type) and 25 as a standard sample
A biaxially stretched polyethylene terephthalate film having a thickness of μm was used by measuring moisture permeability in advance by a cup method. According to this method, the water vapor permeability was determined in the unit of g / m ² · day, and this was used as an index of the water vapor permeability of the coated liner.

(3) Gas Permeability of Corrugated Cardboard Container The corrugated cardboard container was sealed in an empty state and the permeation characteristics were measured at 27 ° C. In the case of carbon dioxide gas, after the inside of the container was replaced with a mixed gas of nitrogen 80: carbon dioxide gas 20 (volume ratio), the time difference of this gas composition was measured by gas chromatography. 2 at
The transmittance at m was determined. Further, in the case of oxygen, after completely replacing the inside with nitrogen, a time change curve of oxygen concentration was measured by the same method to determine the permeability at a pressure difference of 0.2 atm. The unit of the transmittance thus obtained is cc (ST
P) / hr (converted to the standard state), but the transmission coefficients Pco ₂ and Po ₂ in consideration of the thickness of the coating resin and the effective surface area excluding the portions used for sealing the ends or corners.
(Cm ³ (STP) cm cm ⁻² · s ⁻¹ · cmHg
^-1 ) was calculated. The transmission coefficient ratio P
Co ₂ / Po ₂ was calculated.

(4) A commercially available compression tester (CTM-1-5000 type) was used to measure the compressive strength of the corrugated cardboard container.
Was used according to JIS 0212. The compression direction was the facing direction, the test was performed at a compression speed of 10 mm / min, and the maximum compression load (kgf) was used as the compression strength of the corrugated cardboard container. In any of the above measurements, the arithmetic mean value of three measurements was used as the measurement value.

Comparative Test 1 Example 1 A container using the corrugated board described in FIG. Basis weight 2
A low-density polyethylene LDPE polymerized by a high-pressure method and a so-called ultra-low density L copolymerized from ethylene and butene-1 on the surface of a liner paper for corrugated board of 20 g / m ²
The resin film thickness 2 was obtained by blending the LDPE in a weight ratio of 60:40.
Extrusion lamination was performed at 0 μm. As a condition,
The resin temperature immediately below the die was 320 to 325 ° C., the lamination speed was 100 m / min, and the liner surface corona treatment was 5 Kw. Using this resin-coated liner as an outer surface and an aqueous bond by a corrugator, firstly a stepped basis weight of 180 g / m ² of a core was coated, and then the inner surface side was coated with LDPE at a film thickness of 30 μm of a basis weight of 220 g / m ^2. The m ² liners were attached to each other to obtain corrugated paperboard. This paperboard was subjected to normal die-cutting, the joint was joined with a hot melt adhesive, and the A-1 type corrugated board (length L = 288, width W = 19 defined in JIS Z 1507).
0, height H = 115 mm) was created. Pco ₂ of the resin-coated outer liner is 15.0 × 10 ⁻¹⁰ (cm ³ (S
TP) cm cm ⁻² · s ⁻¹ · cmHg ⁻¹ ) and the resin coated inner liner has a water vapor permeability of 32.5 (g / m ^2).
・ Day).

Comparative Example 1 The structure of the outer liner was the same as in Example 1, and the inner liner was used as it was without resin coating.

Comparative Example 2 The outer liner was used without any resin coating,
The structure of the inner liner is the same as in the first embodiment.

Comparative Example 3 A conventional cardboard container was used as it was. There is no resin coating layer.

Comparative Example 4 A container using the corrugated board described in FIG. The coating resin layers of the outer liner and the inner liner are the same as in Example 1.

Test Method With respect to the above five kinds of corrugated board, after pre-treating the kabosu (variety: Oita No. 1) harvested in the middle of September, 2 kg each was packed, and biaxially oriented polypropylene with a width of 40 mm was used as a base material. It was completely sealed as shown in FIG. Five cases were prepared for each type and stored in an atmosphere of 20 ° C. and 65% RH. After storage for about 1 month, the oxygen and carbon dioxide gas concentrations in the corrugated board were measured, and the compressive strength was measured by the method described above. After opening, the quality of kabos was kept good and the quality was good (%), and the peeling was firm on the skin. For defective products, A: yellow, B:
Evaluation was made of the dropout rate, C: wilting, D: incidence of mold and other defects (%), and weight reduction rate (%) based on the total initial weight. Table 1 summarizes the gas composition in each corrugated board, the compressive strength of the container (ratio (%) when the maximum compressive load of the conventional corrugated container before storage is 100), and the results of the storage test of Kavos. Indicated.

[0048]

[Table 1] A, B, C, and D in the column of defective products in the table indicate A: yellowing, B:
Depression, C: wilting, D: mold and other (%).

In the corrugated cardboard of Comparative Example 1 in which only the outer liner was coated with resin, the gas exchange with the outside of the container was controlled through the surface of the outer liner, so that the gas composition in the container was in conformity with CAVOS CA storage conditions. However, the compressive strength of the container became extremely small because the water evaporated from the fruits moved to the liner and the core. In addition, the weight of the fruit also decreased, and the wilting was remarkable. In the corrugated cardboard of Comparative Example 2 in which only the inner liner was coated with resin, there was no migration of transpirational moisture, so the compressive strength of the container was maintained and the weight loss of the fruit was also suppressed. Since the gas exchange with the outside was freely performed through the inner core and the outer liner without the resin coating, the gas composition in the container was almost the same as that of the atmosphere, and yellowing and slumping were extremely large. In the conventional corrugated board without the resin coating of Comparative Example 3, the weight loss was extremely large and most of them were shrunk. In addition, there were many yellow fruits due to the lack of respiratory control. In the corrugated cardboard of Comparative Example 4, gas freely flowed in and out from the flap abutting portion of the outer liner, so breathing could not be suppressed, and there were many yellow fruits. Further, since the resin layer 5 is on the outside, the inner liner is exposed inside the container, absorbs the water evaporated from the fruit, reduces the strength, and promotes the water evaporation of the fruit. On the other hand, in the corrugated cardboard with resin coated on both side liners of Example 1, the simple C
The green color of the peel was maintained due to the respiratory depression due to the A effect, and satisfactory preservation was obtained with almost no weight loss. In addition, the strength of the container did not decrease much compared to the initial stage, which was a practical result.

[Comparative Test 2] Example ² A corrugated board liner base paper having a basis weight of 280 g / m ² was coated with
LDPE (density ρ = 0.918) and ultra-low density LLDPE
Using a 40:60 blend of (ρ = 0.905), extrusion lamination was performed at a film thickness of 25 μm. This was used as an outer liner with the resin coated surface as the outer surface, and the LDPE was used for the inner core and the center core of 180 g / m ² basis weight.
(Ρ = 0.918) coated with a film thickness of 25 μm 2
A 80 g / m ² inner liner was bonded together with an aqueous bond to obtain a corrugated paperboard. Further, die cutting and box making were performed, and A-1 type corrugated board (length L = 288, width W = 19
0, height H = 115 mm) was created. Pco ₂ of the resin-coated outer liner is 13.5 × 10 ⁻¹⁰ (cm ³ (S
TP) cm cm ⁻² · s ⁻¹ · cmHg ⁻¹ ), and the water vapor permeability of the resin-coated inner liner is 39.0 (g / m).
² · day).

2 kg of Ome (variety: Minamitakaume) pre-cooled for 8 hours in a pre-cooling box at 10 ° C. after harvesting
After packing, an adhesive tape having a width of 40 mm and made of biaxially oriented polypropylene as a base material was used, and the exposed end portion of the side corrugated board bonding portion was left as a ventilation adjustment area as shown in FIG. 2 and sealed.

Comparative Example 5 The procedure of Example 2 was repeated except that an adhesive tape was attached only to the abutting portions of the corrugated board on the bottom and the lid, and the I-shaped seal was applied.

Comparative Example 6 The procedure of Example 2 was repeated except that the corner portion 9 was not sealed.

Comparative Example 7 A conventional corrugated board without resin coating was sealed as shown in FIG.

Test method 10 cases of each type were prepared, 20 ° C., 65% R
Stored in H atmosphere. It was opened 5 days after harvesting, and yellowing, wilting, and weight loss rate of ume were evaluated.
, And the percentage (%) of those in which changes were observed in all individuals, and the percentage (%) of reduction was based on the total initial weight. The results are shown in Table 2.

[0056]

[Table 2]

In the sealing methods of Comparative Example 5 and Comparative Example 6, gas can flow in and out through the flap overlapping portions and corners of corrugated cardboard, and in particular, oxygen can be freely supplied, so that the gas permeability coefficient ratio of the container is small and nearly half of the container. Yellowed fruits were produced. Further, although the weight loss due to transpiration is suppressed as compared with Comparative Example 7 in which the resin coating is not performed,
About 20% of the wilting was observed. On the other hand, in the sealing method of Example 2, since the gas exchange with the outside of the container is controlled by the outer liner surface and the exposed end portion of the corrugated board bonding portion on the side surface that has been opened as the ventilation adjustment area, a high gas permeability coefficient ratio is obtained. A large amount of carbon dioxide gas was discharged and an appropriate amount of oxygen was supplied, and yellowing was considerably suppressed even after 5 days of harvesting. Moreover, browning did not occur, weight loss was extremely small, and well-balanced storage stability was achieved. Secured.

[Comparative Test 3] Example 3 A corrugated liner base paper having a basis weight of 220 g / m ² was coated with
LDPE (ρ = 0.918) and ultra-low density LLDPE (ρ
= 0.905) 60:40 blend,
Extrusion lamination was performed at a film thickness of 20 μm. Using this as the outer liner resin-coated surface as the outer surface, having a basis weight of 160 g / ^{m 2} interliner, on the inner surface side LDPE ([rho
= 0.915) with a film thickness of 30 μm and a basis weight of 220
The inner liner of g / m ² was bonded with an aqueous bond to obtain a corrugated paperboard. Further, die cutting and box making are performed.
A-1 type corrugated board (length L = 400, width W = 140, height H = 100 mm) was created. Pco ₂ of the resin-coated outer liner was 16.0 × 10 ⁻¹⁰ (cm ³ (STP).
cm cm ⁻² · s ⁻¹ · cmHg ⁻¹ ), and the water vapor permeability of the resin-coated inner liner is 37.5 (g / m ² · da).
y).

Comparative Example 8 In the corrugated board of Example 3, the film thickness of the coating resin LDPE (ρ = 0.915) of the inner liner was set to 10 μm.
The water vapor permeability of the resin-coated inner liner is 112.5 (g / m ²
・ Day).

Comparative Example 9 A conventional cardboard container was used as it was. There is no resin coating layer. The basis weight of the liner and the size of the container are the same as in Example 3.

Test Method For the above three types of corrugated board, after packing 500 g of spinach pre-cooled in a vacuum pre-cooling cabinet at 5 ° C. for 2 hours after harvesting,
As shown in FIG. 3, it was completely sealed using an adhesive tape having a width of 40 mm as a base material of biaxially oriented polypropylene. Five cases of each type were prepared and stored in an atmosphere of 20 ° C. and 60% RH. After storage for 6 days, the bag was opened and the reduction rate (%) based on the total initial weight was measured for the quality of spinach.

Results With the conventional corrugated board without resin coating of Comparative Example 9, yield 6
The weight loss rate after 3 days was extremely large at 31.5%, indicating complete wither. Further, in the corrugated board using the inner liner having a thin resin coating layer of Comparative Example 8, the moisture permeability is large, so that the weight loss suppression is insufficient, and the weight loss rate after 6 days is 14.4.
%, And the productability was lost. Moreover, the maximum compressive load of the container tended to decrease to 35%. Against these,
In the corrugated board of Example 3, since the moisture permeability of the inner liner was small, the weight loss rate after 6 days was as small as 2.3%, and almost no wilting was observed. In addition, since the outer liner had an appropriately large Pco ₂ , no yellowing of the leaves, no trocar, and no offensive odor occurred, and a sufficient freshness-retaining effect was obtained. Furthermore, there was little decrease in the strength of the container, which was good.

[Comparative Test 4] Example 4 A corrugated board liner base paper having a basis weight of 280 g / m ² was coated with
LDPE (ρ = 0.918) and ultra-low density LLDPE (ρ
= 0.905) 80:20 blend,
Extrusion lamination was performed at a film thickness of 25 μm. The resin coated liner material was evaluated for gas permeation characteristics, and the resin coated surface was used as the outer surface to serve as the outer liner, and LD of the basis weight of 180 g / m ² was applied to the inner core and the inner core.
PE (ρ = 0.918) was coated with an inner liner having a basis weight of 280 g / m ² coated with a film thickness of 30 μm by an aqueous bond to obtain a corrugated paperboard. Further, die cutting and box making were performed, and A-1 type corrugated board (length L = 288, width W = 19
0, height H = 115 mm) was created. The water vapor permeability of the resin-coated inner liner was 32.5 (g / m ² · day).

Comparative Example 10 A corrugated board was prepared in the same manner as in Example 4 except that the blend of LDPE and LLDPE was changed to poly-4-methylpentene 1: TPX.

Comparative Example 11 A corrugated board was prepared in the same manner as in Example 4 except that the blend of LDPE and LLDPE was changed to polyethylene terephthalate.

Test method With respect to the above three kinds of corrugated board, after pretreatment of Cabos (variety: Oita No. 1) harvested in mid-September, 2 kg each was packed, and a biaxially stretched polypropylene having a width of 40 mm was used as a base material for adhesion. The tape was used for complete sealing as shown in FIG. Five cases were prepared for each type and stored at 5 ° C. and 60%. After storage for about 2 months, the quality of the opened cabos was good (%) with good greenness and firmness on the skin, and bad: A: yellowing, B: pitting, C : Browning, D: occurrence rate of mold and others (%), and weight reduction rate (%) based on the total initial weight were evaluated (storage section I). Next, for those with good storage, the distribution using this box is assumed, and
As described above, the exposed end portion of the corrugated board bonding portion on the side surface was left as the ventilation adjustment area and was sealed again. 20 ° C, 65% RH
After being left for 2 weeks, it was opened again and the quality was evaluated (storage section II). Table 3 shows a summary of the transmission characteristics of the resin-coated paper and the corrugated cardboard container and the results of the storage test of the corrugated cardboard.

[0067]

[Table 3] * Pco ₂ × 10 ¹⁰ cm ³ (STP) cm / (c
m ² · s · cmHg) ** A: yellowing, B: pitting, C: browning, D: mold and others (%)

When poly-4-methylpentene 1 having a large carbon dioxide gas permeability coefficient of Comparative Example 10 was used as a coating, the resin itself had a relatively high permeability coefficient ratio, but when processed into a container, cracks occurred, and the results shown in FIG. Even if it is sealed like (storage area 1),
Since the ratio of the permeability coefficient of the container is small, the coefficient of permeability of oxygen is considerably large. Reflecting this permeation property, respiration was hardly suppressed in the storage test with corrugated cardboard, so about 70% of yellowed fruits were produced after 2 months of low temperature storage. Further, when the exposed end portion of the corrugated board corrugated portion on the side surface was opened as a ventilation adjusting area for distribution as shown in FIG. 2, the transmission coefficient ratio of the container was further reduced, and most of the yellowing occurred at room temperature storage for 2 weeks. For the coating of polyethylene terephthalate, Comparative Example 1
As is clear from 1, the carbon dioxide permeability coefficient is extremely small, so the carbon dioxide concentration in the corrugated board becomes extremely high,
There was atelectasis and frequent gas injury. On the other hand, in the coating made of the blend of LDPE and ultra-low density LLDPE of Example 4, a high carbon dioxide gas permeability coefficient and a suitable oxygen supply due to the high permeability coefficient ratio of the container were performed, so even after two months of low temperature storage. Yellowing was considerably suppressed, browning did not occur, and weight loss was extremely small, and sufficient storage stability was secured. At room temperature storage assuming actual distribution, there was a concern that browning would occur with an increase in breathing volume, but by opening the exposed end of the corrugated board bonding part on the side as a ventilation adjustment area as shown in Fig. 2, The gas composition in the container became suitable for the storage of Kabos, and there was almost no gas damage.

[0069]

The storage container made of the corrugated cardboard of the present invention has a remarkably excellent freshness preservation effect of fruits and vegetables, and can be preserved for a long period of time while preventing deterioration of the freshness.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a wall of a cardboard container of the present invention.

FIG. 2 is a perspective view of the assembled cardboard container of the present invention.

FIG. 3 is a perspective view showing an example of a sealed cardboard container of the present invention.

FIG. 4 is a partial cross-sectional view of a wall of a cardboard container of a comparative example.

[Explanation of symbols]

 1 Outer Liner 2 Middle Core 3 Inner Liner 4 Resin Covering Layer 5 Moisture Proof Resin Covering Layer 6 Communication Groove 8 Sealing Tape 9 Corner 10 Edge of Corrugated Cardboard

Claims (7)

[Claims] 1. A) Carbon dioxide permeation coefficient P at 27 ° C.
co ₂ is 5 × 10 ⁻¹⁰ cm ³ (STP) cm / (c
an outer liner that is at least m ² · s · cmHg),
(B) Core and (C) Water vapor permeability at 27 ° C is 100 g / m ² ·
The ratio Pco ₂ of the carbon dioxide gas permeation coefficient and the oxygen permeation coefficient of the container, which is made of corrugated cardboard consisting of an inner liner of day or less, and the end of the corrugated cardboard exposed on the outer surface of the container is substantially closed by a sealing tape. / A container for storing fresh vegetables and fruits having a Po ₂ of 1.5 or more. 2. The inner liner is 100 g / m ² at 27 ° C.
The container for storing fresh vegetables and fruits according to claim 1, which is composed of a liner material having a moisture permeability of not more than day. 3. The fresh fruit and vegetable storage container according to claim 1, wherein the inner liner is composed of a liner material having a resin layer having a moisture permeability at 27 ° C. of 100 g / m ² · day or less as the innermost layer. .. 4. The carbon dioxide permeability coefficient of the outer liner at 27 ° C. is 5 × 10 ⁻¹⁰ cm ³ (STP) cm / (c).
The container for fresh preservation of fruits and vegetables according to any one of claims 1 to 3, which is composed of a liner material having a resin coating of m ² · s · cmHg) or more arranged in the outermost layer. 5. Sealing with a sealing tape completely seals the exposed end portions of the corrugated cardboard paper at the bottom, lid and corners, leaving the exposed end portion of the side bonding portion as a ventilation adjusting portion. The fresh fruit and vegetable storage container according to any one of claims 1 to 4, which is a sealed enclosure. 6. (A) Carbon dioxide permeation coefficient Pco _{2 at} 27 ° C. is 5 × 10 ⁻¹⁰ cm ³ (STP) cm /
(Cm ² · s · cmHg) or more outer liner,
(B) Core and (C) Water vapor permeability at 27 ° C is 100 g / m ² ·
Fruits and vegetables are stored in a container made of corrugated cardboard consisting of an inner liner below the day, and sealing tape is attached to the bottom of the container and the end of the corrugated cardboard exposed on the outer surface of the lid to seal the corners. Sealing tape is also sealed with a tape, and sealing tape is attached to the exposed end of the corrugated board on the side, leaving a ventilation adjustment area if necessary, and the carbon dioxide permeability coefficient and oxygen permeability coefficient of the container are attached. the ratio _{Pco 2} / Po 2 of the 1.
A method for preserving fresh fruits and vegetables, which is characterized in that it is 5 or more. 7. (A) Carbon dioxide permeation coefficient Pco _{2 at} 27 ° C. is 5 × 10 ⁻¹⁰ cm ³ (STP) cm /
(Cm ² · s · cmHg) or more outer liner,
(B) Core and (C) Water vapor permeability at 27 ° C is 100 g / m ² ·
Fruits and vegetables are stored in a container made of corrugated cardboard consisting of an inner liner below the day, and sealing tape is attached to the bottom of the container and the end of the corrugated cardboard exposed on the outer surface of the lid to seal the corners. The sealing tape is also sealed with a sealing tape, and the sealing tape is stuck on the exposed end of the corrugated board on the side, leaving a ventilation adjustment area if necessary, and the ratio of the carbon dioxide gas permeability coefficient to the oxygen permeability coefficient of the container is attached. Pco ₂ / Po ₂ is 1.
A fruit and vegetable package characterized by being 5 or more.