JP2003034380A - Foaming resin molded container with skin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foaming resin molded container with a skin, in which fruit and vegetables can be easily and surely preserved for a long period in a state that the perspiration of the fruit and vegetables is curbed. SOLUTION: A container body 20 has a core layer 21, whose surface is covered with an inner surface skin film 22 and an outer surface skin film 23, both of which are non-permeable to oxygen. A lid 30 has a core layer 31, whose surface is covered with an inner surface skin film 32 and an outer surface skin film 33, both of which are non-permeable to oxygen. Areas 24, 25, 34, 35 are formed on part of the skin films, where the areas are not covered by neither the inner surface skin films nor the outer surface skin films.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamed resin molded container, and more particularly, to storing and storing fruits and vegetables, such as fruits and vegetables, which are still breathing and evaporating after harvesting, for a long period of time without deteriorating their freshness. The present invention relates to an intended foamed resin molded container.

[0002]

2. Description of the Related Art Fruits and vegetables such as fruits and vegetables continue to breathe and evaporate even after being harvested. If left as it is after harvesting, only respiration progresses without nutritional supplementation, and metabolism progresses in a short time resulting in weight loss, resulting in wilting and loss of commercial value. On the other hand, when the oxygen concentration approaches 0% or the carbon dioxide concentration becomes too high in a sealed environment, anaerobic metabolism occurs to give offensive odors and putrefaction increases. For these reasons, fruits and vegetables are stored under a suitable gas environment in which metabolism is suppressed without being abnormal (MA method). It depends on the type of fruits and vegetables, but in many cases, for example, the oxygen concentration is 3 to 5
% And carbon dioxide concentration of 5 to 10%, it is said that it can be stored for a long time without deteriorating the quality. In fact, fruits and vegetables are hermetically packaged and stored with a resin film having oxygen permeability capable of maintaining such a low oxygen concentration environment.

On the other hand, a container body and a lid are provided as a container for storing and distributing fresh food such as fish and fruits and vegetables, and the container body and the lid each have a surface of a core layer which is a foamed resin molding. A foamed resin molded container having a sealable skin, which is a structure covered with an inner skin film and an outer skin film, is used. Further, a foamed resin molded container in which such a skin film is not laminated on the surface is similarly used.

Japanese Patent Laid-Open No. 1-101141 discloses, as an example of a method for producing a foamed resin molding container in which the above-mentioned skin film is laminated, an inner skin which is preformed in a shape along the cavity surface of a male mold. After mounting the film, the mold is clamped, the expandable resin particles are filled and the particles are heated and foamed to form an intermediate molded article in which the inner surface skin film is adhesively laminated on the inner surface side, and then, The outer surface skin film was attached to the exposed outer surface of the intermediate molded product, and the mold was clamped again, and the intermediate molded product and the outer surface skin film that was applied later were heat-bonded in the cavity. The method is described. In addition, JP-A-9-77147
In the publication, a foamed resin molded container in which a skin film is not laminated on the surface, having at least one through hole,
There is described a freshness keeping container in which various functional materials are arranged.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have used a conventionally known foamed resin molding container as described above, under a suitable gas environment in which metabolism is suppressed without making it abnormal, Experiments were carried out in a low temperature environment to see if fruits and vegetables could be stored for a long period of time. As a result, in the case of a hermetically sealed container in which both the container body and the lid body are formed by covering the entire surface of the core layer, which is a foamed resin molded body, with a skin film, the inside of the container is completely blocked from the outside air. ,
I have learned that the environment in which oxygen concentration is close to 0% within a short time causes dew condensation rot. In the case of a foamed resin molded container in which a skin film is not laminated on the surface, compared to the case of a sealed container covered with a skin film, it was possible to store for a long period of time. This is because the oxygen concentration inside is kept almost the same as the atmospheric environment and the fruits and vegetables will not suffocate. In addition, JP-A-9-7714
In the case of a foamed resin molded container having a through hole as described in Japanese Patent Publication No. 7, although fruits and vegetables can breathe sufficiently like a foamed resin molded container having no through hole, the fruit and vegetables are stored for a longer period of time. In order to do so, it is necessary not to suffocate but to suppress the breathing.

The present invention has been made in view of the above circumstances, and in a foamable resin molded container that is sealable and has a container body and a lid, the fruits and vegetables that breathe and evaporate are
An object of the present invention is to provide a foamed resin molded container capable of exerting a breathing suppression effect on fruits and vegetables, which could not be achieved by the conventional container described above, and capable of being stored for a medium to long term without lowering freshness.

[0007]

A foamed resin molded container according to the present invention for solving the above-mentioned problems comprises a container body and a lid body, and the container body and the lid body each have a core layer which is a foamed resin molded body. A sealable container whose surface is covered with an inner skin film and an outer skin film, wherein the core layer of either or both of the container body and the lid is covered with the inner skin film. The non-covered area and the area not covered by the outer surface side skin film are partially provided.

In the above foamed resin molded container, since a region of the foamed resin molded body forming the core layer is not covered with the oxygen-impermeable skin film, the foamed resin molded body passes through the region and is foamed resin molded. A controlled amount of oxygen penetrates into the sealed container through the body core layer. The amount is greater than when the entire surface of the core layer is covered by the skin film and smaller than when it is not covered at all. Therefore, by appropriately adjusting the area not covered by the skin film, it becomes possible to create an oxygen concentration environment most suitable for preservation of the fruits and vegetables to be preserved in the container, and at a desired low oxygen concentration. The medium-to-long term storage can be easily performed.

The amount of oxygen passing through the foamed resin molding forming the core layer is determined by the area of the narrower one of the region not covered by the inner skin film and the region not covered by the outer skin film. Basically depends. Therefore, the "area of the narrower region" is determined in consideration of the environmental gas condition which is the optimum storage condition for the fruits and vegetables to be preserved, for example, the oxygen concentration is about 2 to 10%. In the usual case, the "area of the narrower area" is 0 .., which is the total area of the inner peripheral surface area and the outer peripheral surface area of the container with the lid on.
It is in the range of 05 to 20%, preferably 0.1 to 15%.

In the case of a container for storing fruits and vegetables, by providing an area not covered with the skin film only on the lid, it can be reused as a container by replacing only the lid even if it is partially soiled. There is a merit that you can do it. For that reason, the area not covered by the inner skin film and the area not covered by the outer skin film are not formed on the container body side, but are formed only on the lid body. Is highly desirable.
Furthermore, in this case, the container body is a lid body using a foamed resin molded container in which the entire surface of the core layer that has been conventionally used is covered with an inner skin film and an outer skin film. There is also an advantage that only one can be replaced and used.

In the present invention, as the expandable resin particles used for molding the core layer, those which have been used for manufacturing conventional foamed resin molded containers with a skin can be used as they are.
For example, as the expandable resin particles, pre-expanded thermoplastic resin particles having a bulk density of 8 to 100 g / L such as polystyrene-based resin, polypropylene-based resin, polyethylene-based resin, and aromatic polyester-based resin are used. The foam molding conditions may be the same as conventional ones, provided that the foamed resin molded product after molding has air permeability.

The skin film is a normal thermoplastic such as polypropylene resin, polyester resin, high-impact polystyrene resin, polyethylene resin, ethylene-vinyl acetate copolymer resin, provided that it is impermeable to oxygen. A film or sheet which is a resin and has a wall thickness of about 0.1 to 3.0 mm can be used. In addition,
As the skin film, a non-foamed resin film is desirable.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A foamed resin molded container with a skin according to the present invention will be described below with reference to embodiments. FIG. 1 is a sectional view showing an embodiment of a foamed resin molded container 10 with a skin, which is composed of a container body 20 and a lid 30. The container body 20 is in the shape of a box with an open top, and is a core layer 21 which is, for example, a polystyrene resin bead-type in-foam molded product.
And an inner surface skin film 22 that is a non-foamed polystyrene film that covers the inner surface thereof, and an outer surface skin film 23 that is a non-foamed polystyrene film that covers the outer surface.

The inner skin film 22 has an opening 24, and the outer skin film 23 also has an opening 25.
Due to the openings 24 and 25, a region of the core layer 21 not covered by the inner skin film 22 and the outer skin film 2 are formed.
A region not covered by 3 is formed. Openings 24, 2
The area of 5 should be adjusted to an appropriate size according to the fruits and vegetables to be preserved.

Similarly, the lid 30 also covers the core layer 31 which is a bead type in-foam molded product of polystyrene resin, the inner surface skin film 32 which is a non-foamed polystyrene film that covers the inner surface, and the outer surface. For example, the outer surface skin film 33 is a non-foamed polystyrene film. The inner skin film 32 has an opening 34.
The outer surface skin film 33 is also provided with an opening 35. As a result, the core layer 31 of the lid body 30 also has a region not covered with the inner skin film 32 and a region not covered with the outer skin film 33. The areas of the openings 34 and 35 are also adjusted to an appropriate size according to the fruits and vegetables to be preserved. In such a foamed resin molded container 10 with a skin, an amount of oxygen controlled by the opening area formed in the skin film will enter the inside of the container. Although not shown, the container body 20 has an opening 24,
Instead of providing 25, the openings 34 and 35 may be provided only in the lid body 30. Further, the lid 30 is the container body 20.
You may provide the convex rib which fits in the inner peripheral edge.

[0016]

EXAMPLES Next, the present invention will be described with reference to examples, but it goes without saying that the present invention is not limited to the following examples. [Example 1] A storage test was performed on pears. The reason for choosing pears is that they are fruits and vegetables with a small respiratory rate of 50 [CO ₂ mg / kg / hr] or less. The test includes
Three types of sealable containers were prepared, and a long-term storage test of pears was carried out in a refrigerator in which pears were stored and the storage environment was set to 2 ° C. Both the container body and the lid body are formed by pre-expanding polystyrene resin pre-expanded particles 50 times in a mold. The container body of all three types of containers has an outer size of 380.
mm × 300 mm × 250 mm, total thickness of wall surface and bottom surface is 20 mm, and outer dimension of lid is 380 mm
It is × 300 mm × 20 mm.

As the container A (Comparative product 1), a polystyrene resin foam-molded product is used as it is, and the molding surface of the foamed resin is the same on all surfaces of the container body and the lid. The container B (comparative product 2) is a polystyrene resin foam molded product whose entire surface is covered with a skin film which is a non-foamed polystyrene film having a thickness of 0.5 mm, and the container body and the lid are covered with a skin film. The molding surface of the foamed resin is not exposed at all.

As shown in FIG. 2, in the container C (product of the present invention), the container body 20 is a non-foamed polystyrene film having a thickness of 0.5 mm on the entire surface of the core layer 21 which is a foamed product of polystyrene resin. The cover body 30 is covered with the skin films 22 and 23, and the cover body 30 is also covered with the inner skin film 32 and the outer skin film on the surface of the core layer 31 which is a foam molded product. The outer skin film 32 and the outer skin film 33 have circular openings 34, 35 at opposite positions, so that the inner skin film 32 and the outer skin film are formed on the front and back sides of the lid 30. A region not covered by 33 is formed.
In this example, the area of the narrower area of the area not covered by the inner surface skin film and the area not covered by the outer surface skin film is the inner surface area and outer circumference of the container with the lid closed. It is 6% of the total surface area.

The pears P contained in each of the containers A, B, and C were three in number, and after the storage, an oxygen-impermeable adhesive film was attached to the overlapping portion of the container body and the lid to seal the inside. The average weight of one pear immediately before storage was 400 g / piece. Also, five sets of the same were prepared, and the oxygen concentration in the container and the average weight of the stored pears were measured on the 3rd, 30th, 60th, 120th and 150th days. The measurement results are shown in FIGS. As shown in FIG. 3, the oxygen concentration in the container is maintained in the range of about 17 to 20% in the container A, and there is no significant change from the oxygen concentration in the atmosphere. In container B, the oxygen content rapidly decreased due to pear breathing, and reached about 0% in about 10 days. In container C, the oxygen concentration is 10
The range of about 17% is maintained, and the low oxygen concentration state is maintained in the container.

As shown in FIG. 4, the weight of pears decreased with the lapse of days, but the reduction rate was large in the container A, and the weight reduction was 6% in about 120 to 130 days, and 8% in 180 days. It is decreasing. However, the weight of the container C, which is the product of the present invention, is reduced by about 3% even after 180 days. In the container B, dew condensation rot occurred after 30 days of storage, and the commercial value was completely lost at that time.

When the appearance of the pear after storage was observed, it was 8%.
When the weight was reduced, many wrinkles were generated on the appearance (the surface of the pear), and the commercial value was greatly lost. Even if the weight was reduced by 6%, the appearance was wrinkled, and the reduction in commercial value could not be denied. On the other hand, when the weight is reduced by 3%, there is no wrinkle on the surface,
The color tone at the beginning of storage was maintained almost as it was. Container A can also be stored for a long time (about 130 days), but Container C, which is a product of the present invention, retains sufficient freshness even after storage for 180 days, that is, over half a year. It turns out that it is extremely effective for preservation.

[Example 2] A storage test was conducted on spinach. The reason for choosing spinach is that the respiratory volume is 2
This is because the fruits and vegetables have a large respiration rate of 00 [CO ₂ mg / kg / hr] or more. Three types of sealed containers A, B, and C were prepared in the same manner as in Example 1. However, in the container C (product of the present invention), in addition to the lid body, the region not covered with the skin film is also provided on the four side surfaces of the container body in the same manner, and the region not covered with the inner skin film and the outer surface are provided. The total area of the narrower one of the areas not covered with the side skin film was set to be 15% of the total area of the inner peripheral surface area and the outer peripheral surface area of the container with the lid covered.

Using this container, spinach preservation experiments were conducted. Prepare 3 sets of the same one containing 3 bundles of 400g spinach and 1st on the 1st, 3rd and 5th day.
Each was opened and the average weight of chlorophyll in the spinach was measured. The measurement result is shown in FIG. As shown in FIG. 5, the amount of chlorophyll in spinach decreased with the lapse of days, but the reduction rate was large in Container A and decreased by 15% on the third day. In the container C which is the product of the present invention, the decrease was 5% on the 3rd day and 12% on the 5th day. It should be noted that, in the container B, dew condensation rot occurred after 1 day of storage, and the commercial value was lost at that time.

When the appearance of the spinach after storage was observed, the appearance turned yellow at 15% reduction, and the commercial value was greatly lost. At 12% decrease, some yellowing was seen, but it still had sufficient commercial value. No yellowing was observed at 5% reduction. From this, it is understood that the container of the present invention is also effective for storing leafy fruits and vegetables having a large respiration rate such as spinach.

In the above experiment, gas chromatography (GC-4 manufactured by Shimadzu Corporation) was used to measure the oxygen concentration.
A (TCD)) was used to sample and measure the air inside the sealed container. In addition, chlorophyll was measured using a chlorophyll meter (SPAD-502 manufactured by Fujiwara Seisakusho Co., Ltd.), and the third pair of spinach leaves were sandwiched between measuring heads and SPA.
The D value was measured. Details are shown below.

Regarding gas concentration, measurement condition Model Shimadzu Corporation gas chromatography GC-4A TCD (heat conduction detector) column molecular sieve 5A carrier gas helium (flow rate: 1 Kg / cm ² ) temperature INITIAL TEMP 100 ° C. FINAL TEMP 120 ° C. INJECTIONPORT At the time of collecting at 100 ℃, stick a raw rubber with double-sided tape to prevent outside air from entering the container, and then use a syringe to
cc of gas was collected. Oxygen was measured by measuring 1 cc of ambient air and setting it as 20.8%.

Chlorophyll measuring method Measuring instrument Fujiwara Seisakusho chlorophyll meter SPAD-502 Measuring site Spinach root leaves 3rd leaf judgment criterion The average value 35 of 10 SPAD value measurements immediately after harvest was taken as 100%. The average value 30 of five SPAD value measurements on a radial day was set to 85%, and a decrease of 15% was used as a criterion. With a decrease of 15%, there is no commercial value due to yellowing.

The chlorophyll meter SPAD-502 is different from the conventional measurement using a color code, and the chlorophyll content is represented by a numerical value (SP).
The ADAD) is a measuring device, and the SPAD value is obtained by an optical density difference measuring method. The spectral characteristic of chlorophyll is 400
There are absorption peaks at ~ 500 nm and 600-700 nm, and light in the region of 700 nm or more is hardly absorbed, but the optical density is measured, and the SPA is calculated based on the difference.
D value is calculated. In addition, chlorophyll meter SPAD-502
Is a soil crop cultivation diagnostic equipment commercialization project of the Ministry of Agriculture, Forestry and Fisheries (S
oil & Plant Analyzer Dev
This is a measuring instrument that has been developed in the abbreviation "SPAPMENT".

[0029]

EFFECTS OF THE INVENTION By using the foamed resin-molded container with skin according to the present invention, medium and long-term preservation of fruits and vegetables can be easily and reliably carried out while respiration is suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view illustrating an embodiment of a foamed resin molded container with a skin according to the present invention.

FIG. 2 is a diagram illustrating a foamed resin molded container with a skin used in Example 1.

FIG. 3 is a graph showing changes in the oxygen concentration in the container in Example 1.

FIG. 4 is a graph showing changes in heavy utilization of pears in Example 1.

5 is a graph showing changes in chlorophyll of spinach in Example 2. FIG.

[Explanation of symbols]

10 ... Foamed resin molded container with skin, 20 ... Container body, 3
0 ... Lid, 21, 31 ... Core layer, 22, 32 ... Inner surface skin film, 23, 33 ... Outer surface skin film, 24, 2
5, 34, 35 ... Aperture (area not covered with skin film)

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3E035 AA11 BA01 BB02 BD01 CA02                 3E067 AA11 AB08 AB09 BA02A                       BA05A BB14A BB17A BB25A                       BC06A BC07A CA03 EA32                       FA01 FC01 GB01 GD01

Claims (3)

[Claims] 1. A container body and a lid body, both of the container body and the lid body having a core layer, which is a foamed resin molded body, having a surface covered with an inner skin film and an outer skin film. A container that can be sealed, and the core layer of either or both of the container body and the lid has an area not covered by the inner skin film and an area not covered by the outer skin film. A foamed resin molded container characterized by being provided. 2. The area of the narrower area of the area not covered by the inner skin film and the area not covered by the outer skin film is the area of the inner peripheral surface of the container with the lid covered. The foamed resin molding container according to claim 1, wherein the total area of the outer peripheral surface is 0.05 to 20%. 3. The foamed resin molded container according to claim 1, wherein the region not covered with the inner skin film and the region not covered with the outer skin film are present only in the lid.