JPH11227805A - Packaging bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep an opening open at the time of unsealing a packaging bag by forming the packaging bag using a laminate comprising, sequentially from an exterior, a biaxially oriented film and a heat-shrinkable film each having a factor of heat shrinkage of a specific value and a thermoplastic resin layer which are laminated via urethane containing adhesive. SOLUTION: A laminate 1 used for the packaging bag comprises, sequentially from an exterior, a biaxially oriented film 11 with a factor of heat shrinkage of 2% or less, an adhesive layer 12, an aluminum foil 13, an adhesive layer 14, a heat-shrinkable film 15 with a factor of heat shrinkage of 5% or more, an adhesive layer 16 and a thermoplastic resin layer 17 which are laminated, while a printed layer 18 is provided on an internal face of the biaxially oriented film 11. The bag is filled with contents, and end rims at four sides are heat- bonded for sealing to form the packaging bag. When the bag is subjected to retort sterilization or the like, heat shrink of the heat-shrinkable film 15 causes the laminate 1 to be curled with its internal, face recessed. Thus when one of heat-bonded parts of the packaging bag is cut off, an opening can be kept open.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging bag for boil sterilization and retort sterilization, which can maintain an open state when the packaging bag is opened.

[0002]

2. Description of the Related Art Conventionally, packaging bags used for applications such as boil sterilization and retort sterilization include biaxially stretched polyethylene terephthalate (PET) / adhesive / aluminum foil (A).
L) / adhesive / polyolefin, PET / adhesive / biaxially stretched nylon (ON) / adhesive / polyolefin, ON
/ Adhesive / polyolefin and the like, and polyolefins such as polypropylene, high-density polyethylene, medium-density polyethylene, and linear low-density polyethylene are generally used. However, in the case of the packaging bag having the above configuration, when the packaging bag is opened, the films are in close contact with each other at the opening, so that the opening cannot be maintained and the contents cannot be easily taken out. .
In particular, in the case of contents containing a large amount of water, it is extremely difficult to take out the contents because the contents are in close contact with the film and the opening does not remain open.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a boil sterilizing method in which, when a heat-bonded portion of a packaging bag is cut off and opened, the contents can be easily taken out by keeping the opening open. A packaging bag for retort sterilization.

[0004]

Means for Solving the Problems A biaxially stretched film having a heat shrinkage of 2% or less, a heat shrinkable film having a heat shrinkage of 5% or more, and a thermoplastic resin layer are formed of a urethane adhesive from the outer surface. A packaging bag made of a laminated body and having a structure in which the thermoplastic resin layer is heat-bonded with the thermoplastic resin layer as an inner surface. In this case, by performing heat treatment such as boil sterilization or retort sterilization after filling the contents in the packaging bag, the heat-shrinkable film constituting the laminate shrinks, and the laminate constituting the packaging bag has a concave inner surface. And it becomes a curved state. Therefore, when the packaging bag is opened by the cut line, the laminated body constituting the packaging bag is curled in a concave shape and curved, so that the opening portion is largely opened, and it is extremely easy to take out the contents. Also, by laminating using a urethane-based adhesive when manufacturing a laminate for producing a packaging bag, heat shrinkage is not applied to the heat-shrinkable film during the laminating process, so heat shrinkage is not performed. The curable film does not contract and curl. Therefore, the bag can be made in the same manner as a general packaging bag, and the contents can be automatically filled and packed.

In the above-mentioned packaging bag, the aluminum foil is laminated with the urethane-based adhesive between the biaxially stretched film and the heat-shrinkable film, so that the contents can be easily taken out and oxygen or the like can be obtained. Thus, a packaging bag having excellent preservability can be obtained even when contents that easily change in quality are packaged.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a configuration of a laminate for producing a packaging bag according to a first embodiment of the present invention, FIG. 2 is a plan view showing a packaging bag according to the first embodiment, and FIG. FIG. 4 is a view showing a state in which the bag is opened, and FIG. 4 is a view showing a structure of a laminate for producing the packaging bag of the second embodiment, wherein 1, 1 ′ is a laminate, and 2a and 2b are heat-bonded portions. 3, infeed, 4
Is a cut line, 5 is an opening, 11 is a biaxially stretched film, 12, 1
Reference numerals 4 and 16 denote an adhesive layer, 13 denotes an aluminum foil, 15 denotes a heat-shrinkable film, 17 denotes a thermoplastic resin layer, and 18 denotes a printed layer.

A first embodiment of the packaging bag of the present invention is a packaging bag having a shape shown in FIG. 2 manufactured by using a laminate having a configuration shown in FIG. The configuration of the laminate 1 used for the packaging bag of the first embodiment is as follows: a biaxially stretched film 11, an adhesive layer 12, an aluminum foil 13, an adhesive layer 14, a heat-shrinkable film 15, and an adhesive layer 16 And a thermoplastic resin layer 17 are laminated. The printing layer 18 is provided on the inner surface of the biaxially stretched film 11. The adhesive layers 12, 14, 16 are layers made of a urethane-based adhesive. Since the packaging bag of the first embodiment has excellent gas barrier properties, it is a packaging bag suitable for packaging contents that are easily degraded by oxygen or the like.

[0008] The shape of the first embodiment of the packaging bag of the present invention is:
As shown in FIG. 2, the heat-bonded portions 2a, 2b along the four edges
And is sealed at a predetermined distance from the inner end of the thermal bonding portion 2a at the edge of the thermal bonding portion 2b provided at right angles to both ends of the thermal bonding portion 2a on one side. A four-sided seal bag in which two notches 3 opposed to each other are formed, and a line connecting the two notches 3 is a cut line 4 for opening the packaging bag. The shape of the packaging bag of the present invention is arbitrary, and may be a self-supporting bag or a pillow-type bag. Generally, a four-sided seal bag or a self-supporting bag is used as a packaging bag for use in performing retort sterilization or boil sterilization.

The state in which the packaging bag of the first embodiment is opened is as shown in FIG. This bag is filled with the contents and sterilized by retort or boil, whereby the heat-shrinkable film 15 shrinks due to the high temperature during sterilization, and the laminate 1 has a concave inner surface on which the heat-shrinkable film 15 is laminated. It is in a state of being curled so that Therefore, cut line 4
As shown in FIG. 3, the laminated body 1 on both sides constituting the packaging bag curls into an inner concave shape at the opening portion along the perforation line 4 and is curved, as shown in FIG. A large opening 5 is formed and the opening 5
Can be kept open, making it very easy to remove the contents.

A second embodiment of the packaging bag of the present invention is as shown in FIGS. As shown in FIG. 4, the structure of the laminate 1 'used in the packaging bag of the second embodiment is, in order from the outer surface, a biaxially stretched film 11, an adhesive layer 12, a heat shrinkable film.
This is a configuration in which a layer 15, an adhesive layer 16, and a thermoplastic resin layer 17 are laminated. The printing layer 18 is provided on the inner surface of the biaxially stretched film 11. The adhesive layers 12, 16 are layers made of a urethane-based adhesive. The second embodiment is suitable as a packaging bag for packaging contents that do not require much gas barrier properties.

The biaxially stretched film 11 used in the packaging bag of the present invention is a film having a heat shrinkage of 2% or less, and the heat shrinkable film 15 is a film having a heat shrinkage of 5% or more. is there. The heat shrinkage ratio in the present invention is a value of the shrinkage ratio when immersed in hot water of 90 ° C. for 30 minutes. The heat-shrinkable film 15 may be a film having a heat shrinkage of at least 5% in at least one direction. In this case, the direction of the cutout line 4 of the packaging bag and the shrinkage direction of the heat-shrinkable film 15 are matched. It is necessary to put.

Heat Shrinkable Film Constituting Laminates 1, 1 '
15 may be any heat-shrinkable film having a heat-shrinkage ratio of 5% or more, such as polyethylene terephthalate film,
Nylon film can be suitably used. As the heat shrinkable film, for example, heat shrinkage% (flow direction, width direction)
Is a 33/40 polyethylene terephthalate film, Space Clean S2600 (Toyobo), a heat shrinkage% (flow direction, width direction) is a 35/35 nylon film, Emblem US (Unitika Co., Ltd.), a heat shrinkage% Emblem MS (Unitika), a 25/25 nylon film (flow direction, width direction), heat shrinkage%
Unilon S-300 (Idemitsu Oil), a 30/30 nylon film (flow direction, width direction), heat shrinkage%
Bonyl S (Mitsubishi Chemical) which is a 23/24 nylon film (flow direction, width direction) can be used.

The biaxially stretched film 11 constituting the laminates 1 and 1 'used for producing the packaging bag of the present invention is 2
An axially stretched polyethylene terephthalate film, a biaxially stretched polypropylene film and the like are suitable. As the thermoplastic resin layer 17, in the case of a packaging bag for retort sterilization, an unstretched polypropylene film, an unstretched ethylene-propylene copolymer film, a high-density polyethylene, or the like can be used. In the case of a packaging bag for boil sterilization, a medium density polyethylene film, a linear low density polyethylene, or the like can be used in addition to the above-mentioned films. As the adhesive layers 12 and 16, a urethane-based adhesive having excellent heat resistance is used.

According to the method for manufacturing a packaging bag of the present invention, a laminate is manufactured by laminating by a dry lamination method using a urethane-based adhesive, and the bag making process can be performed in the same manner as in the prior art. it can. By laminating by dry lamination method, even if the adhesive is applied to the heat-shrinkable film surface, do not dry it at a temperature high enough to shrink the heat-shrinkable film in the adhesive drying process. Thus, the heat-shrinkable film does not shrink during dry lamination and the laminates 1 and 1 'do not curl. Since the heat-shrinkable film undergoes heat shrinkage in the heat treatment step of sterilizing by retort or boil-sterilizing to cause curl, the opened state can be maintained when opened.

[0015]

According to the present invention, a biaxially stretched film having a heat shrinkage of 2% or less, a heat shrinkable film having a heat shrinkage of 5% or more, and a thermoplastic resin layer are laminated with a urethane adhesive from the outer surface. It is a packaging bag made of a body and thermally bonded with a thermoplastic resin layer as an inner surface. In this case, by performing heat treatment such as boil sterilization or retort sterilization after filling the contents in the packaging bag, the heat-shrinkable film constituting the laminate shrinks, and the laminate constituting the packaging bag has a concave inner surface. And it becomes a curved state. Therefore, when the packaging bag is opened by the cut line, the laminated body constituting the packaging bag is curled in a concave shape and curved, so that the opening portion is largely opened, and it is extremely easy to take out the contents. In addition, by laminating using a urethane-based adhesive when manufacturing a laminate for manufacturing a packaging bag, the drying temperature shrinks even when the adhesive is applied to the heat-shrinkable film. By setting the temperature not to be set, it is possible to prevent the laminate from curling. In the above packaging bag, the aluminum foil is laminated with a urethane-based adhesive between the biaxially stretched film and the heat-shrinkable film,
It is possible to obtain a wrapping bag excellent in gas barrier property from which contents can be easily taken out.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of a laminate for producing a packaging bag according to a first embodiment of the present invention.

FIG. 2 is a plan view showing the packaging bag according to the first embodiment.

FIG. 3 is a view showing a state in which the packaging bag according to the first embodiment is opened.

FIG. 4 is a diagram showing a configuration of a laminate for producing a packaging bag according to a second embodiment of the present invention.

[Explanation of Signs] 1, 1 'Laminated body 2a, 2b Thermal bonding part 3 Cut 4 Cut line 5 Opening 11 Biaxially stretched film 12, 14, 16 Adhesive layer 13 Aluminum foil 15 Heat shrinkable film 17 Thermoplastic resin Layer 18 Printing layer

Claims (2)

[Claims] 1. A laminate in which a biaxially stretched film having a heat shrinkage of 2% or less, a heat shrinkable film having a heat shrinkage of 5% or more, and a thermoplastic resin layer are laminated with a urethane adhesive in order from the outer surface. A packaging bag comprising a body, and having a configuration in which the thermoplastic resin layer is heat-bonded with the thermoplastic resin layer as an inner surface. 2. The packaging bag according to claim 1, wherein an aluminum foil is laminated between the biaxially stretched film and the heat-shrinkable film with a urethane-based adhesive.