US20080031553A1

US20080031553A1 - Package for food

Info

Publication number: US20080031553A1
Application number: US11/462,299
Authority: US
Inventors: Norihiro Tokita; Yumi Okamura
Original assignee: Unicharm Corp
Current assignee: Unicharm Corp
Priority date: 2006-08-03
Filing date: 2006-08-03
Publication date: 2008-02-07

Abstract

A package for food is provided which can preserve the freshness of fresh food after being stored in a refrigerator for a long period of time. A container bag of a synthetic resin sheet has an opening which can be closed with a zipper to seal the inside. A water-absorbing sheet is contained inside the container bag, and this water-absorbing sheet is located on the inside of a first side, a second side, and a bottom of the container bag. Accordingly, drips can be absorbed by the water-absorbing sheet, with fresh food being surrounded by the water-absorbing sheet, and it is possible to maintain the moisture within the bag.

Description

This application is based on and claims the benefit of priority from Japanese Patent Application No. 2004-15061, filed on Jan. 23, 2004, the content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a package for food suitable for storage of fresh food which requires humidity for storage, such as fresh vegetables, raw meats, and fresh fish.
2. Related Art
Upon storing fresh food, such as fresh vegetables, raw meats, and fresh fish, in a refrigerator, a certain level of humidity is required for preserving their freshness. However, since the humidity in the refrigerator is relatively low, the freshness of such fresh food is prone to be lost if they are stored in the refrigerator just as they are. In addition, food storage packs of synthetic resin sheets formed in the shape of a bag are commercially available. When fresh food is directly placed in such a food storage pack and the storage bag is stored in a refrigerator, drips oozing out of the fresh food adhere to the food again in the bag main body. This causes discoloration of the fresh food, and the surface of the fresh food is prone to rot due to bacteria contained in the drips, which makes long-term storage of the fresh food in a fresh condition difficult.
A packaging bag for food disclosed in Japanese Unexamined Patent Application, Laid open Publication No. H2-57583 has a protecting member provided on the inside of a bag formed of a nylon substrate or a polyethylene substrate, and this protecting member is made by laying a liquid-permeable sheet on an absorbing material made of a liquid-absorbing material. This packaging bag for food is intended to prevent drips oozing out of fresh food from re-adhering to the food by making the absorbing material of the protecting member absorb the drips, and to maintain an appropriate humidity using the drips absorbed in the absorbing material.
However, when the food packaging bag disclosed in Japanese Unexamined Patent Application, First Publication No. H2-57583 is opened it remains open and no means for closing this opening is provided. Accordingly, when the drips absorbed in the absorbing material of the protecting member disposed inside the bag evaporate in the bag, the water escapes out of the bag from the opening. This makes it difficult to retain the moisture in the bag for a long period of time, and accordingly the food contained in the bag is prone to drying out within a short time.
Japanese Unexamined Patent Application, Laid open Publication No. H2-57583 discloses an embodiment in which the protecting member is laid only on the inside of one side of the bag, and another embodiment in which a protecting member is laid on the inside of each of the two sides of the bag. However, since no protecting member is provided on the bottom facing the opening of the bag, when the bag main body is placed in a refrigerator in the vertical orientation with its opening facing upward, drips oozing out of the food are prone to accumulate at the bottom inside the bag and the drips tend to readhere to the food.
Furthermore, since the protecting member is simply inserted in the bag, the liquid-permeable sheet of the protecting member does not always face food when the food is put in the bag though its opening. For example, the food may be placed between the absorbing material of the protecting member and the bag main body. In this case, the drips absorbed in the absorbing material are prone to readhere to the food. In addition, with the structure in which a respective protecting member is laid on the inside of each of the two sides of the bag as well, it is difficult to reliably place the food between the protecting members when the food is put in the bag.
Furthermore, although Japanese Unexamined Patent Application, Laid open Publication No. H2-57583 discloses that the protecting member is made in the shape of a bag, it does not teach the structure of this bag-shape protecting member and how it is disposed in the bag.
Furthermore, when an excessive pressure is applied to the bag containing the food, the drips absorbed in the absorbing material are prone to return to the surface of the sheet and readhere to the food since the liquid-permeable sheet provided to the protecting member does not have a structure to prevent backflow of liquid.

SUMMARY OF THE INVENTION

The present invention is directed to solve the above-described problems of conventional arts, and an object thereof is to provide a package for food which can maintain the inside of a container bag at an optimum humidity and is resistant to accumulation of drips at the bottom of the container bag.
The present invention is a package for food comprising a container bag and a water-absorbing sheet provided inside the container bag, wherein the container bag is made from a packing material of a synthetic resin sheet and has a first side and a second side which have a rectangular shape and face each other, an opening communicating to the inside of the container bag is defined on one side of the rectangle, and a bottom facing the opening and two other sides are closed, wherein zippers which mate with each other inside the opening to seal the opening are provided to each inner surface of the first side and the second side, and the water-absorbing sheet is disposed along the inner surfaces of the first side, the bottom, and the second side when the container bag is flattened, and wherein the water-absorbing sheet is made by laying a liquid-permeable surface layer over a liquid-absorbing layer made of a hydrophilic material, and the surface layer is located facing the inside of the container bag.
In the above-described package for food, the zippers are provided at the opening of the container bag, and the inside of the container bag can be sealed by closing the opening when food is placed in the container bag. Accordingly, once drips oozing out of the food are absorbed in the liquid-absorbing layer, water in these drips helps to provide moisture within the sealed container bag, which makes it possible to prevent the food from being dried out within a short time.
Furthermore, since the water-absorbing sheet is disposed on the inside of the bottom of the container bag, the drips oozing out of the food are absorbed in the liquid-absorbing layer at the bottom of the container bag as well. Thus, even when the package for food is stored in the vertical orientation with the opening thereof facing upward, it becomes possible to prevent degradation of the food for a long period of time.
Furthermore, the present invention may be constructed such that an area of a part of the water-absorbing sheet located on the inside of the second side is smaller than an area of a part of the water-absorbing sheet located on the inside of the first side when the container bag is flattened.
In this case, the area of the part of the water-absorbing sheet located on the inside of the second side is preferably one half or less, more preferably one third or less than the area of the part of the water-absorbing sheet located on the inside of the first side.
With the above-described package for food, since the water-absorbing sheet is present on the first side and at the bottom, the drips oozing out of the food can be easily absorbed by the water-absorbing sheet either when the package for food is stored with the first side facing downward or when stored with the bottom facing downward. Furthermore, since the area of the part of the water-absorbing sheet located on the inside of the second side is small, it becomes possible to check the color and condition of the food contained therein from outside by viewing it through the second side.
Furthermore, the present invention is constructed such that an absorption bag is formed from the water-absorbing sheet and an opening of the absorption bag is located in an inside of the opening of the container bag.
With this package for food, by placing food in the absorption bag located within the container bag, it becomes possible to reliably make the water-absorbing sheet absorb the drips oozing out of the food irrespective of the orientation of the storage of the package for food.
Furthermore, in a preferable embodiment of the present invention, at least a part of the water-absorbing sheet is fixed by bonding to the inner surface of the first side and the inner surface of the second side.
When the water-absorbing sheet is fixed to the inner surface of the first side and the inner surface of the second side of the container bag, the part of the water-absorbing sheet disposed on the first side and the part of the water-absorbing sheet disposed on the second side are separated from each other when the inner space of the container bag is expanded. Thus, it is ensured that the surface layer of the water-absorbing sheet faces the food contained in the container bag, and it becomes possible to prevent the drips absorbed in the liquid-absorbing layer from coming into direct contact with the food.
Furthermore, the present invention may be constructed such that the bottom of the container bag is folded in a gusset in order to make the bottom of the container bag expandable.
When the bottom of the container bag is folded in a gusset, the bottom of the container bag is expanded when the inner space of the container bag is expanded. This makes the container bag suitable for a vertical storage in which the opening faces upward.
Furthermore, in the present invention, it is preferable that the surface layer of the water-absorbing sheet be a synthetic resin sheet having liquid-permeable holes formed therein, and the liquid-permeable holes be formed with a wider hole opening area at a surface of the surface layer than a hole opening area on a liquid-absorbing layer side, or the liquid-permeable holes are formed obliquely with respect to the thickness direction of the surface layer.
When the liquid-permeable holes are formed in this manner, when pressure is applied from outside to the container bag containing food and consequently the food is pressed against the water-absorbing sheet, the drips contained in the liquid-absorbing layer are less likely to return to the surface of the surface layer through the liquid-permeable holes.
The present invention enables sealing of the inside of the container bag, to retain the moisture within the container bag, and to preserve the freshness of the food in the container bag for a long period of time. Furthermore, it becomes possible to reliably make the water-absorbing sheet absorb the drips oozing out of the food when the container bag is stored in the vertical orientation with the opening faces upward.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing a package for food in a first embodiment of the present invention;

FIG. 2 is a cross-sectional view showing the package for food having food contained therein;

FIG. 3 is an enlarged cross-sectional view showing a water-absorbing sheet;

FIG. 4 is an enlarged cross-sectional view showing another embodiment of the water-absorbing sheet;

FIG. 5 is an exploded perspective view showing a package for food of a second embodiment of the present invention;

FIG. 6 is a cross-sectional view showing another embodiment of a container bag; and

FIG. 7 is a cross-sectional view showing the package for food employing the container bag shown in FIG. 6 which has food contained therein.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is an exploded perspective view showing a package for food in a first embodiment of the present invention; FIG. 2 is a cross-sectional view showing the package for food having food contained therein; and FIG. 3 and FIG. 4 are enlarged cross-sectional views showing respective embodiments of a water-absorbing sheet.
A package for food 1 shown in FIG. 1 is comprised of a container bag 2 and a water-absorbing sheet 4 provided on the inside of the container bag 2.
The container bag 2 is formed from a packing material of a transparent or translucent synthetic resin sheet. The synthetic resin constructing the packing material is one of low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polyethylene (PP), polyethylene terephthalate (PET), ethylene-vinylacetate copolymer (EVA), and the like; or multi-layered sheet formed by laminating one or more of the above-listed resins. Furthermore, a resin having the so-called gas barrier property, such as polyvinylidene chloride (PVDC), helps to retain the moisture in the container bag 2.
The container bag 2 has a rectangular or square shape in plan view when it is flattened. The container bag 2 is formed by folding a single sheet of the above-described packing material or by overlaying two sheets of the packing material each other.
The container bag 2 of the embodiment shown in FIG. 1 is formed by overlaying two sheets of the rectangular packing material on one another. This container bag 2 has a rectangular first side 21 and a similarly rectangular second side 22 which face each other. The sheets of packing material are not attached together on a front line 23 of the rectangle, and this front line 23 defines an opening 24. At a bottom 25 which faces the front line 23 and on two sides 26 and 27, the sheets of the above-described packing material are attached together on the periphery of the first side 21 and the second side, whereby the sheets are closed. At the bottom 25 and on the sides 26 and 27, the sheets of the above-described packing material are fused by means of heat sealing or ultrasonic sealing, or are bonded together with an adhesive, such as hot melt type adhesive.
A zipper 29 for closing the opening 24 is provided on the inside of the opening 24. This zipper 29 is comprised of a male zipper 29 a and a female zipper 29 b which are mated to each other. Both the male zipper 29 a and the female zipper 29 b are formed of a deformable soft synthetic resin material. The male zipper 29 a is fixed by bonding to the inner surface of the second side 22 and is attached thereto, parallel to the front line 23. The female zipper 29 b is fixed by bonding to the inner surface of the first side 21 and is attached thereto, parallel to the front line 23.
As shown in FIG. 2, the opening 24 can be closed by mating the male zipper 29 a with the female zipper 29 b along the front line 23 along the entire length of the zipper.
The water-absorbing sheet 4 is formed in a rectangular shape having an inner surface 41 and an outer surface 42. The water-absorbing sheet 4 is folded on the bottom side, and has a first part 43 extending from the folding line part 45 to the front line 46, and a second part 44 extending from the folding line part 45 to a back line 47. In this embodiment, the water-absorbing sheet 4 is folded flatly into the two parts at the folding line part 45 so that the area of the second part 44 is smaller than that of the first part 43. The area of the second part 44 is one half or less, preferably one third or less, and more preferably one quarter or less of the area of the first part 43.
At least a part of the outer surface 42 of the first part 43 of the water-absorbing sheet 4 is bonded to the inner surface of the first side 21 of the container bag, by a hot melt type adhesive, with the water-absorbing sheet 4 being inserted into the container bag 2. Furthermore, at least a part of the outer surface 42 of the second part 44 of the water-absorbing sheet 4 is bonded to the inner surface of the second side 22 of the container bag 2, by a hot melt type adhesive. The folding line part 45 of the water-absorbing sheet 4 faces the inner surface of the bottom 25 of the container bag 2.
The front line 46 of the water-absorbing sheet 4 is located apart from the front line 23 of the container bag 2 and is closer to the inside of the bag. It is preferable that the front line 46, or the vicinity thereof, of the water-absorbing sheet 4 be bonded to the inner surface of the first side 21 and the back line 47, or the vicinity thereof of the water-absorbing sheet 4 be bonded to the second side 22.
As shown in FIG. 3 in an enlarged view, the water-absorbing sheet 4 has a surface layer 51 positioned on the inner surface side, and a liquid-absorbing layer 52 positioned on the outer surface 42 side. The surface layer 51 is a film formed from a synthetic resin material, and the surface layer 51 is formed bonded on the surface of the liquid-absorbing layer 52, or formed by lamination on the surface of the liquid-absorbing layer 52 by means of melt extrusion of the synthetic resin material.
Numerous liquid-permeable holes 53 are formed in the surface layer 51. When viewed from the inner surface 41 of the water-absorbing sheet 4, the shape of the opening of the respective liquid-permeable holes 53 is circular or elliptical. The hole opening area A2 of the liquid-permeable holes 53 on the side adjacent to the liquid-absorbing layer 52 is smaller than the hole opening area A1 on the surface of the surface layer 51, i.e., the inner surface 41. Furthermore, thin flaps 53 a are formed protruding from the peripheries of the liquid-permeable holes 53 adjacent to the liquid-absorbing layer 52. Since the liquid-permeable holes 53 have a smaller hole opening area A2 on the side adjacent to the liquid-absorbing layer 52 and have the thin flaps 53 a, it becomes easy to prevent the drips absorbed in the liquid-absorbing layer 52 from oozing out of the surface of the surface layer 51 even if the food 5 is pressed against the water-absorbing sheet 4.
The surface layer 51 is formed from a laminated film formed by laminating sheets of one or more of LDPE, MDPE, LLDPE, PP, PET, and EVA. Preferably, the surface layer 51 is a laminated film having a film of HDPE on inner surface 41 and a film of LDPE on the liquid-absorbing layer 52 side. Such a laminated film makes it easy to form holes having different hole opening areas A1 and A2 when the liquid-permeable holes 53 are formed by a needling or perforating process, and to form the thin flaps 53 a.
The surface layer 51 is selected to have a thickness of between 3 μm and 70 μm, preferably between 5 μm and 30 μm, and a basis weight ranging from 10 g/m²to 100 g/m², preferably ranging from 10 g/m²to 60 g/m². The surface layer 51 contains inorganic fillers of, e.g., titanium oxide, calcium carbonate, barium sulfate, in a range between 5% by weight and 30% by weight for the purpose of whitening. Whitening the surface layer 51 can help to maintain the appearance, giving a clean impression of the inner surface 41 of the water-absorbing sheet 4.
The hole opening diameter of the liquid-permeable holes 53 ranges from 0.1 mm and 2 mm when viewed from the inner surface 41, and the arrangement pitch between the liquid-permeable holes 53 is between 0.1 mm and 2 mm. The substantial ratio of hole opening area of the liquid-permeable holes 53 in the surface layer 51 is between 0.1% and 80%, preferably between 5% and 45%.
Setting the hole opening diameter, the arrangement pitch, and the ratio of hole opening area of the liquid-permeable holes 53 within the above-described ranges makes it easier to make the liquid-absorbing layer 52 absorb the drips oozing out of the food 5 by means of the hydrophilic property of the liquid-absorbing layer 52, and this helps to prevent the drips absorbed in the liquid-absorbing layer 52 from flowing back to the inner surface 41. Furthermore, this makes it possible to maintain the appearance of the inner surface 41 with a white color and in a condition giving a clean impression.
The liquid-absorbing layer 52 is formed of a hydrophilic material; for example, it is formed of airlaid pulp manufactured by stacking pulp using the airlaid technique and bonding the pulp together with an acryl binder. The mass per unit area thereof preferably ranges between 20 g/m²and 100 g/m², but this range is not limiting. The liquid-absorbing layer 52 is not limited to such airlaid pulp as long as the liquid-absorbing layer 52 is formed from a material having a high water-holding property. It may be made of nonwoven fabric formed from cellulosic fibers, such as pulp or rayon, a stack of absorbent paper, nonwoven fabric including synthetic resin fibers which have undergone hydrophilization treatment, hydrophilic foam materials, such as cellulose sponge, or the like.
In the package for food 1, the first part 43 of the water-absorbing sheet 4 is fixed on the inner surface of the first side 21 of the container bag 2 and the second part 44 is fixed on the inner surface of the second side 22. Thus, it becomes possible to separate the first part 43 from the second part 44 of the water-absorbing sheet 4 when the inner space of the bag is expanded by demating the male zipper 29 a and the female zipper 29 b to open the opening 24 and to separate the first side 21 from the second side 22 of the container bag 2.
Furthermore, when the front line 46 or its vicinity and the back line 47 or its vicinity of the water-absorbing sheet 4 are fixed by bonding to the inner surface of the first side 21 of the container bag 2 and the inner surface of the second side 22, respectively, it is assured that the front line 46 and the back line 47 of the water-absorbing sheet 4 is separated from each other when the inner space of the container bag 2 is expanded.
Accordingly, when the fresh food 5, such as fresh vegetables, raw meats, or fresh fish, is put therein from the opening 24 of the container bag 2, it becomes possible to reliably make the food 5 come into contact with the surface layer 51 of the water-absorbing sheet 4.
When the male zipper 29 a and the female zipper 29 b are mated to each other after the food 5 is placed, it is possible to close the opening 24 of the container bag 2 to seal the inside of the container bag 2.
Although the drips oozing out of the fresh food 5 adhere to the surface layer 51 of the water-absorbing sheet 4, the drips are withdrawn into the liquid-absorbing layer 52 through the liquid-permeable holes 53 and are retained there due to the hydrophilic property of the surface layer 51. Since the liquid-absorbing layer 52 is separated from the fresh food 5 by the surface layer 51, the drips absorbed in the liquid-absorbing layer 52 are less likely to adhere to the fresh food 5 again. Thus, bacteria contained in the drips are less likely to adhere to the surface of the fresh food 5 and it becomes possible to prevent the food 5 from rotting.
When the package for food 1 is stored in a refrigerator, the temperature inside the container bag 2 decreases to about 4° C. and consequently the humidity within the bag is reduced. In this case, free water in the drips retained in the liquid-absorbing layer 52 evaporates into the inner space of the bag, which helps to retain the humidity in the inner space of the bag. As a result, it becomes possible to preserve the freshness of the fresh food 5 for a long period of time.
In the first embodiment, as shown in FIG. 2, while the water-absorbing sheet 4 is laid on the inner surface of the first side 21 of the container bag 2, the water-absorbing sheet 4 is provided only to a part of the second side 22.
Accordingly, it becomes possible to visually check the color of the fresh food 5 in the container bag 2, and the visual inspection of the freshness of the food therein is made possible without opening the container bag 2.
Furthermore, when the container bag 2 is stored with the first side 21 facing downward, as shown in FIG. 2, the first part 43 of the water-absorbing sheet 4 is located beneath the fresh food 5 and it is possible to make the first part 43 absorb the drips oozing out of the food 5. Furthermore, since a part of the water-absorbing sheet 4 is disposed also on the inside of the bottom 25 of the container bag 2, when the container bag 2 is stored in the vertical orientation in which the bottom 25 faces downward, the lower portion of the fresh food 5 is wrapped with the folding line part 45 and the second part 44 of the water-absorbing sheet 4. Accordingly, it is possible to make those parts of the water-absorbing sheet 4 absorb the drips oozing out of the food 5, and consequently it is possible to prevent the drips from accumulating at the inner surface of the packing material of the container bag 2.
As described above, since the container bag 2 can be stored in two orientations, i.e., the vertical and horizontal orientations, in the refrigerator, it becomes possible to effectively use the storage space of the refrigerator.
Furthermore, when pressure is applied to the container bag 2, for example, when packages for food 1 are stacked together and the food 5 is pressed against the water-absorbing sheet 4, the liquid-absorbing layer 52 is pressed. However, as shown in FIG. 3, the liquid-permeable holes 53 in the surface layer 51 are structured to easily prevent the backflow of the liquid, the drips absorbed in the liquid-absorbing layer 52 are prevented from oozing to the surface of the surface layer 51. Accordingly, it becomes possible to prevent the drips from re-adhering to the food 5 when an external pressure is applied.
FIG. 4 is am enlarged cross-sectional view showing a water-absorbing sheet 4A of another embodiment.
In the water-absorbing sheet 4A, while a surface layer 51A of a synthetic resin film is laid over the liquid-absorbing layer 52, the liquid-permeable holes 53 b formed in the surface layer 51A are formed obliquely with respect to the thickness direction of the surface layer 51A (i.e., the direction normal to the surface layer 51A). When such a water-absorbing sheet 4A is used, drips adhering to the surface of the surface layer 51A are easily withdrawn into the liquid-absorbing layer 52 and retained there due to the hydrophilic property of the liquid-absorbing layer 52 while the drips absorbed in the liquid-absorbing layer 52 are less likely to pass through the liquid-permeable holes 53 b and return to the surface of the surface layer 51A.
FIG. 4 is an exploded perspective view showing a package for food 100 of the second embodiment of the present invention.
The package for food 100 has the same container bag 2 as in the package for food 1 of the first embodiment. A liquid-absorbing bag 104 is contained inside of the container bag 2. The liquid-absorbing bag 104 is formed from the water-absorbing sheet 4 shown in FIG. 3 or FIG. 4. The liquid-absorbing bag 104 is constructed by folding a single sheet of the rectangular water-absorbing sheet 4 in two, or by overlaying two sheets of the water-absorbing sheet 4 together so that the surface layers 51 or 51A of the water-absorbing sheets 4 face each other.
The liquid-absorbing bag 104 has an opening 105 which is a single open side of the rectangle, and a bottom 106 and two side parts 107 and 108 are closed. The liquid-absorbing bag 104 is contained within the container bag 2 with the opening 105 of the liquid-absorbing bag 104 facing the opening 24 of the container bag 2.
At least a part of the outer surface of a first side 109 of the liquid-absorbing bag 104 is fixed by bonding to the inner surface of the first side 21 of the container bag 2, and at least a part of the outer surface of a second side 110 of the liquid-absorbing bag 104 is fixed by bonding to the inner surface of the second side 22 of the container bag 2 with the liquid-absorbing bag 104 being contained within the container bag 2. Furthermore, it is preferable that the opening 105 or its periphery of the liquid-absorbing bag 104 is fixed by bonding to the inner surfaces of the first side 21 and the second side 22.
With this package for food 100, similar to the first embodiment, since the opening 105 of the liquid-absorbing bag 104 is opened as a result of unmating of the zipper 29 to open the opening 24 of the container bag 2 and to expand the inner space of the bag, it becomes possible to reliably place the fresh food 5 in the liquid-absorbing bag 104.
Furthermore, since the water-absorbing sheet 4 is provided on the insides of the first side 21, the second side 22, and the bottom 25 of the container bag 2, it is possible to make the water-absorbing sheet 4 absorb drips oozing out of the food 5 in either cases when the package for food 100 is stored in the horizontal or vertical orientation, thereby preventing the drips from remaining directly in contact with the inner surface of the packing material which constitutes the container bag 2.
In the package for food 1 of the first embodiment and the package for food 100 of the second embodiment, since the water-absorbing sheet 4 is fixed by bonding to the inner surface of the first side 21 and the inner surface of the second side 22 of the container bag 2, the water-absorbing sheet 4 opens, following the inner surface of the bag, when the inner space of the container bag 2 expands. However, the present invention is not limited to these embodiments, and the water-absorbing sheet 4 may be contained in the bag without being bonded to the inner surface of the bag in the packages for food 1 and 100. In this case, the water-absorbing sheet 4 can be taken out of the container bag 2 and be exchanged with a new one when the container bag 2 becomes stained.
Alternatively, in each of the above-described embodiments, an adhesive layer which has a weak adherence and is capable of being striped repeatedly may be attached to the outer surface of the water-absorbing sheet 4, and the water-absorbing sheet 4 may be bonded to the inner surface of the first side 21 and the inner surface of the second side 22 of the container bag 2 via this adhesive layer. In this case, it is possible to expand the water-absorbing sheet 4 together with the bag main body by expanding the inner space of the container bag 2. In addition, it is possible to exchange a stained water-absorbing sheet 4 with a new one with ease.
FIG. 6 is a cross-sectional view showing only a container bag 200 of another embodiment, and FIG. 7 is a cross-sectional view showing the water-absorbing sheet 4 having the same shape as in FIG. 1, provided within the container bag 200.
While the container bag 200 is made from the same synthetic resin sheet as that used for the container bag 2 and has a first side 21, a second side 22, a front line 23 defining an opening 24, and sides 26 and 27, the packing material is folded in a gusset at a bottom 225. The container bag 200 is structured so that the packing material is extended at the bottom and consequently the bottom 225 is expanded when the fresh food 5 is placed in the container bag 2, as shown in FIG. 7.
When such a container bag 200 is used, the container bag 200 can be stably placed in the vertical orientation in which the bottom 225 faces downward, as shown in FIG. 7.
It should be noted that the liquid-absorbing bag 104 shown in FIG. 5 may be used and be contained in the container bag 200.

EXAMPLES

Example

The packages for food 1 shown in FIG. 1 and FIG. 2 were made as prototypes.
The container bag 2 was made from LDPE having a thickness of 60 μm and a basis weight of 56 g/m². The surface layer 51 of the water-absorbing sheet 4 was a composite resin film which had a thickness of 25 μm and a basis weight of 24 g/m²and was formed by laminating HDPE and LDPE. The hole opening diameter of the liquid-permeable holes 53 when viewed from the inner surface 41 was set to 0.6 mm and the arrangement pitch of the liquid-permeable holes 53 was set to 0.65 mm. The substantial ratio of hole opening of the liquid-permeable holes 53 at the surface layer 51 was between 15% and 22%.
The liquid-absorbing layer 52 was airlaid pulp which had a thickness of 0.9 mm and a mass per unit area of 60 g/m², and was formed by bonding pulp together with an acryl binder. The liquid-absorbing layer 52 and the surface layer 51 were fixed to each other using a hot melt type emulsion-type adhesive having a mass per unit area of 3.0 g/m².

Comparative Example 1

The liquid-absorbing bag 104 shown in FIG. 3 was used solely.

Comparative Example 2

The container bag 2 was used solely.

Comparative Example 3

A commercially available food storage pack made from a synthetic resin sheet was used.

Evaluation Method

A fresh cucumber was placed in each container bag of the above-described Example and Comparative Examples and was stored in a refrigerator set at 4° C. After two days and seven days of storage, the cucumbers in the container bags were inspected.

(1) After Two Days

Although the cucumbers of the Example, Comparative Example 3, and Comparative Example 4 were acceptable for eating, the cucumber of Comparative Example 2 showed deterioration in the freshness and therefore was not acceptable for eating.

(2) After Seven Days

The surface of the cucumber of the Example was wet and remained fresh, and the cucumber was acceptable for eating.
As for Comparative Example 2, the surface of the cucumber was dried out, it was not hard when touched, was discolored, and was not acceptable for eating. As for Comparative Example 3 and Comparative Example 4, although the surfaces of the cucumbers were wet, the cucumbers were hard and discolored and were not acceptable for eating.
While preferred embodiments of the present invention have been described and illustrated above, it is to be understood that they are exemplary of the invention and are not to be considered to be limiting. Additions, omissions, substitutions, and other modifications can be made thereto without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered to be limited by the foregoing description and is only limited by the scope of the appended claims.

Claims

1. A package for food comprising;

a container bag; and

a water-absorbing sheet provided inside the container bag,

wherein the container bag is made from a packing material of a synthetic resin sheet and has a first side and a second side which have a rectangular shape and face each other, an opening communicating to the inside of the container bag is defined on one side of the rectangle, and a bottom facing the opening and two other sides are closed,

wherein zippers which mate with each other inside the opening to seal the opening are provided to each inner surface of the first side and the second side, and the water-absorbing sheet is disposed along the inner surfaces of the first side, the bottom, and the second side when the container bag is flattened, and

wherein the water-absorbing sheet is made by laying a liquid-permeable surface layer over a liquid-absorbing layer made of a hydrophilic material, and the surface layer is located facing the inside of the container bag.

2. The package for food according to claim 1, wherein an area of a part of the water-absorbing sheet located on the inside of the second side is smaller than an area of a part of the water-absorbing sheet located on the inside of the first side when the container bag is flattened.

3. The package for food according to claim 2, wherein the area of the part of the water-absorbing sheet located on the inside of the second side is one half or less of the area of the part of the water-absorbing sheet located on the inside of the first side.

4. The package for food according to claim 1, wherein an absorption bag is formed from the water-absorbing sheet and an opening of the absorption bag is located inside the opening of the container bag.

5. The package for food according to claim 1, wherein at least a part of the water-absorbing sheet is fixed by bonding to the inner surface of the first side and the inner surface of the second side.

6. The package for food according to claim 1, wherein the bottom of the container bag is folded in a gusset in order to make the bottom of the container bag expandable.

7. The package for food according to claim 1, wherein the surface layer of the water-absorbing sheet is a synthetic resin sheet having liquid-permeable holes formed therein, and the liquid-permeable holes are formed having a wider hole opening area at a surface of the surface layer than a hole opening area on a liquid-absorbing layer side.

8. The package for food according to claim 1, wherein the surface layer of the water-absorbing sheet is a synthetic resin sheet having liquid-permeable holes formed therein, and the liquid-permeable holes are formed obliquely with respect to a thickness direction of the surface layer.