JPH11208680A - Packaging bag - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To be able to completely seal foods, such as cooked or semi-cooked foods, to cook the foods in a microwave while keeping the foods in a packaging bag, and to generate steam generated during the cooking. Accordingly, it is an object of the present invention to provide a low-cost packaging bag which has an effect of steaming food stored in the packaging bag and can release internal pressure in the packaging bag to prevent the bag from breaking. SOLUTION: A rectangular bag body material having a heat-adhesive resin layer in an inner layer is folded with the inner layer being inside with a gap provided so that a pair of opposing ends do not overlap, and the gap is provided. On the inner surface, a tape material having a heat-adhesive resin layer wider than the gap and having a heat-adhesive resin layer on both surfaces is heat-bonded at both side edges of the tape material in parallel to the pair of opposite ends to form two envelope-shaped seal portions. In a packaging bag made into a shape having a cylindrical body having an end sealing portion by thermally bonding the openings at both ends of the cylindrical body, the gap of the bag body material of the tape material was provided. A packaging bag, characterized in that a heat-adhesive resin layer on a surface that is heat-adhered to an inner layer of a site is made of a heat-adhesive resin layer having easy peelability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a liquid substance, a solid substance,
Alternatively, the present invention relates to a packaging bag for packaging a food or the like made of a mixture thereof, and more specifically, a liquid material, a solid, or a food or the like made of a mixture of these is stored in a packaging bag and heated by a microwave oven. While being able to cook,
The present invention relates to a packaging bag capable of releasing steam or the like generated in the packaging bag by heating and cooking to prevent the packaging bag from being broken.

[0002]

2. Description of the Related Art Conventionally, cooked or semi-cooked foods such as meat noodles, anmanman, shumai, dumplings, hamburgers, hot dogs, spaghetti, yakisoba, yakidon, rice noodles, and the like are made of plastic. Packaged foods that are stored in a packaging bag and cooked by heating with a microwave oven when eating are on the market. However, when the packaging bag containing such food is heated together with the packaging bag in a microwave oven, the internal pressure inside the packaging bag rises due to the steam generated from the food and the thermal expansion of the internal air.
There has been a problem that the packaging bag is suddenly broken, the food stored in the packaging bag is scattered, and the inside of the microwave oven is soiled.

In order to solve this problem, before cooking by heating in a microwave oven, usually, a hole is previously formed in a packaging bag with a sharp object, and the end of the packaging bag is cut off with scissors or the like. The internal pressure of the bag was released to prevent the bag from breaking. However, the method of releasing these internal pressures is quite troublesome, and at the same time, the steam generated by the start of the heating and cooking is immediately released to the outside of the packaging bag, and the steaming effect by the steam is reduced and the taste is reduced. In order to save time, for example, a resin-based nonwoven fabric or the like is used for the packaging bag, a ventilation material having a valve structure is attached, or an easily peelable resin layer is used on the entire inner layer of the packaging bag. Has been done.

However, in the method of using the nonwoven fabric for the packaging bag, since the nonwoven fabric does not have moisture-proof properties, the moisture in the food in the packaging bag is scattered to the outside at the time of distribution, sale, etc., and the food is dried. And when the food is a liquid, the liquid leaks out. Further, the method of attaching the ventilation material having the valve structure has a problem that the cost of the ventilation material having the valve structure itself is high and equipment for attaching the ventilation material is required. Further, the method of using the easily peelable resin layer on the entire inner surface of the packaging bag has a problem that the cost of the packaging bag is increased and a release port for steam and internal pressure when cooking is performed cannot be specified.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to completely seal a cooked or semi-cooked food. The food can be prevented from drying out and can cope with the case where the food is a liquid, and can be cooked by a microwave oven while the food is stored in a packaging bag. It is an object of the present invention to provide a low-cost packaging bag that has the effect of steaming the food stored in the packaging bag and allows internal pressure in the packaging bag to escape from a predetermined portion to prevent the bag from being broken.

[0006]

The inventor of the present invention has conducted various studies to solve the above problems, and as a result, claim 1 has been obtained.
The packaging bag according to the aspect of the invention is characterized in that a rectangular bag body material having a heat-adhesive resin layer in the inner layer is folded with the inner layer inward in a state where a gap is opened so that a pair of opposing ends do not overlap with each other. A tape material having a heat-adhesive resin layer wider than the gap and having a heat-adhesive resin layer on both sides thereof, on the inner surface of the portion provided with A cylindrical body having a cylindrical seal portion, and in a packaging bag made into a shape having an end seal portion by thermally bonding the openings at both ends of the cylindrical body, the tape body of the bag body material The heat-adhesive resin layer on the surface that is heat-adhered to the inner layer at the portion where the gap is provided is made of a heat-adhesive resin layer having easy peelability. With such a configuration, the cooked or semi-cooked food can be completely sealed, the drying of the food can be prevented, and even if the food is a liquid, the food can be handled. Can be cooked by a microwave oven while being stored in the packaging bag, and the internal pressure that increases in the packaging bag is increased by the envelope-shaped seal portion while the effect of steaming the food stored in the packaging bag by the steam generated during the heating cooking is exerted. It is possible to obtain a low-cost packaging bag that can escape and prevent the bag from being broken.

According to a second aspect of the present invention, in the packaging bag of the first aspect, at least one of the two envelope-shaped seal portions has a seal width smaller than that of the end seal portion. It is characterized by having. With this configuration, the steam generated by heating and the air that expands thermally can be more reliably released from the envelope-shaped seal portion to prevent the bag from breaking, and
The release of internal pressure can be adjusted to enhance the steaming effect.

[0008] The invention described in claim 3 is based on claim 1,
3. The packaging bag according to 2, wherein the heat-adhesive resin layer on the surface of the tape material that is heat-bonded to the inner layer of the bag body material is made of a mixed resin of a polypropylene resin, a polyethylene resin, and an olefin copolymer rubber. It is characterized by the following. With this configuration, it is possible to obtain a heat-adhesive resin layer having excellent resistance to oil and heat and having easy peeling properties, and to provide a retort packaging bag (a packaging bag capable of high-temperature and high-pressure sterilization). it can. Also, since only a high-cost heat-adhesive resin layer having easy peelability is used on one side of the tape material, the cost of the packaging bag is lower than when the entire package inner layer is used as in the past. Can be lowered.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The above-mentioned present invention will be described in detail below. First, the tape material will be described. In the present invention, as the resin used for the heat-adhesive resin layer having the easy-peeling property of the tape material, the sealing property, the easy-peeling property, particularly, from the viewpoint of oil resistance and heat resistance. A mixed resin of a polypropylene-based resin, a polyethylene-based resin, and an olefin-based copolymer rubber is preferable.

The polypropylene resin as one composition of the mixed resin is, for example, a crystalline propylene random copolymer, which is composed of propylene and ethylene, butene-1, pentene-1, hexene-1,3-methylbutene-1,4- Α such as methylpentene-1 and octene-1
And a random copolymer with an olefin. Of these, a crystalline propylene-ethylene random copolymer is preferable. The random copolymer may be a mixture with a homopolypropylene obtained by multi-stage polymerization.

Next, as the polyethylene resin which is one composition of the mixed resin, for example, any one of ethylene alone such as high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene and high-density polyethylene is used. In addition to being able to use the union, propylene, butene-1, pentene-1, hexene-1, 3-methylbutene-1, 4-methylpentene-1, α-olefin such as octene-1, or crystallinity with vinyl acetate, or A low-crystalline or non-crystalline random or block copolymer, or a mixture thereof can be used. Among them, a high-pressure low-density polyethylene is preferable.

Next, examples of the olefin copolymer rubber, which is a composition of the mixed resin, include ethylene,
Two kinds of monoolefins such as propylene, butene-1, hexene-1,4-methylpentene-1, or
Three or more monoolefin copolymer rubbers, and two of the above monoolefins and dicyclopentadiene, 1, 4
-Hexadiene, cyclooctadiene, methylene norbornene, non-conjugated diolefins such as ethylidene norbornene, or butadiene, copolymer rubber with conjugated diolefins such as isoprene can be used, among which ethylene propylene copolymer rubber, Ethylene butene copolymer rubber and propylene butene copolymer rubber are preferred.

[0013] Next, the heat-adhesive resin layer having easy peelability of the tape material is made of a mixed resin of a polypropylene resin, a polyethylene resin and an olefin copolymer rubber as described above. The mixing ratio of each composition of the mixed resin is 45 to 65% by weight for the polypropylene resin and 35 to 55% for the polyethylene resin with respect to 100% by weight of the mixed resin.
% By weight, and the olefin copolymer rubber is suitably used in the range of 2 to 5% by weight. Also, its thickness is 20
6060 μm is suitable, and preferably 25-50 μm.

Further, if necessary, the heat-adhesive resin layer having an easy-peeling property of the tape material may include a support made of the mixed resin and a homopolypropylene or a crystalline propylene random copolymer or the like. Crystallinity of resin and ethylene homopolymer or α-olefin such as propylene, butene-1, pentene-1, hexene-1,3-methylbutene-1,4-methylpentene-1, octene-1 or propylene, or vinyl acetate Alternatively, a low-crystalline or non-crystalline random or block copolymer, or a mixture thereof may be co-extruded, in which case the thickness of the mixed resin and the thickness of the support May be appropriately selected according to the type of food, the content, the packaging form of the packaged food, the transportation conditions, and the like.

Other than the above-mentioned mixed resin which can be used as the heat-adhesive resin layer having an easy peeling property of the tape material, for example, ethylene-vinyl acetate copolymer resin, modified polyethylene, modified polypropylene, etc. Modified polyolefin resin and the like can be mentioned,
In the case of a food that does not require consideration of oil resistance, heat resistance, and the like, it can be used in the same manner as the mixed resin.

Next, since the core material on which the heat-adhesive resin layer having the easily peelable property of the tape material is provided is a basic base material constituting the tape material, it is mechanically, physically, chemically and so on. Synthetic resins having excellent properties can be used. For example, polyester-based, polyamide-based, polypropylene-based, polycarbonate-based, and polyacetal-based resins can be used. Stretched stretched films are preferred. Alternatively, synthetic paper or the like can be used. The thickness of the film may be any thickness that can maintain the necessary minimum strength and rigidity of the tape material as a basic material, and is suitably about 12 to 30 μm in consideration of cost.
In addition, the film may have a barrier property as a film coated with polyvinylidene chloride or a film formed with a vapor-deposited layer of an inorganic substance such as silicon oxide, if necessary. Further, the film may be printed as necessary or may be colored.

Next, the resin used for the heat-adhesive resin layer provided on the surface of the core material opposite to the surface where the heat-adhesive resin layer having easy peelability is provided is compatible with the inner layer of the bag body material. And it must be completely thermally bonded to the inner layer of the bag body material. Therefore, although it is determined by the resin used for the inner layer of the bag body material, usable resins include, for example, high-pressure low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene. Propylene, butene-1, pentene-1, hexene-1,3-methylbutene-1,4
Α-olefins such as -methylpentene-1 and octene-1 or crystalline or low-crystalline or non-crystalline random or block copolymers with vinyl acetate, or mixtures thereof, or homopolypropylene or A crystalline propylene random copolymer or the like can be used.

By the way, the embodiment in which the heat adhesive resin layers are provided on both sides of the core material as the tape material has been described so far.
The tape material is not limited to this configuration. For example, the tape material may be composed of only the above-mentioned heat-adhesive resin layer having easy peelability.

Next, the bag body material will be described. In the present invention, the resin used for the inner layer of the bag body material is easily peelable from the heat-adhesive resin layer provided on one surface of the tape material. It has to be a resin which is completely heat-bonded to the heat-adhesive resin layer provided on the other surface and is excellent in heat resistance. Therefore, the resin used for the inner layer of the bag body material needs to be selected in relation to the heat-adhesive resin layers provided on both sides of the tape material. In addition to being able to use any ethylene homopolymer such as high density polyethylene, medium density polyethylene and high density polyethylene, propylene,
Α-olefin such as butene-1, pentene-1, hexene-1,3-methylbutene-1,4-methylpentene-1, octene-1, or crystallinity with vinyl acetate,
Alternatively, a low-crystalline or non-crystalline random or block copolymer, or a mixture thereof,
Homopolypropylene or crystalline propylene random copolymer can be used.

As the film used as the outer layer of the bag body material, a synthetic resin having excellent properties in mechanical, physical, chemical and the like is used because it is a basic material constituting the packaging bag. For example, polyester-based, polyamide-based, polypropylene-based, polycarbonate-based, and polyacetal-based resins can be used, and cellophane, synthetic paper, and the like can also be used. Further, the film used as the outer layer,
In general, printing is often performed on the inner layer side of the film, so that the film used as the outer layer is required to have printability, and a stretched film stretched biaxially is preferable. The thickness of the film may be a thickness capable of maintaining the minimum strength and rigidity as a basic material, and is suitably about 12 to 30 μm in consideration of cost. In addition, the film may have a barrier property as a film coated with polyvinylidene chloride or a film formed with a vapor-deposited layer of an inorganic substance such as silicon oxide, if necessary.

Further, in the present invention, an intermediate layer may be provided between the inner layer and the outer layer, and the intermediate layer usually cannot sufficiently function as a packaging bag only with the inner layer and the outer layer. It is provided in cases and the like. The functions include gas barrier properties, mechanical toughness, bending resistance, puncture resistance, impact resistance, abrasion resistance, cold resistance, heat resistance, chemical resistance, etc., and are required for packaging bags. These final functions are achieved by providing an intermediate layer. As the substrate used as the intermediate layer, for example, polyethylene terephthalate, polyamide, polyethylene,
Polyolefins such as polypropylene, polyvinyl chloride,
Films of polycarbonate, polyvinyl alcohol, ethylene-propylene copolymer, saponified ethylene-vinyl acetate copolymer, etc., films coated with polyvinylidene chloride, films on which inorganic materials such as silicon oxide are deposited, or polyvinylidene chloride Or paper, cellophane, synthetic paper, non-woven fabric, or the like. Further, one or more of these base materials can be used in combination. Note that the thickness of the base material is not particularly limited as long as the function required for the packaging bag can be satisfied, and can be appropriately selected as needed. In the case where the intermediate layer is provided on the bag body in this way, it is needless to say that it is necessary to provide the tape member with a similar function.

Next, a more detailed description will be given with reference to an embodiment shown in the drawings. 1 is a perspective view of a first embodiment of a packaging bag according to the present invention, FIG. 2 is an enlarged sectional view of a main part of FIG. 1, and FIG. 3 is a main part layer of the first embodiment of the packaging bag according to the present invention. FIG. 4 is a perspective view of the packaging bag according to the first embodiment of the present invention in the middle of cooking, FIG. 5 is a main part layer configuration diagram of the packaging bag according to the second embodiment of the present invention, and FIG. FIG. 3 is a main part layer configuration diagram of a third embodiment of a packaging bag according to the present invention, in which 1, 1 'and 1 "are packaging bags, 2, 2' and 2" are bag body materials, and 3, 3 ',
3 "is a tape material, 4 is an end seal portion, 5 and 6 are envelope-shaped seal portions, 8, 8 'are peeling portions, 21 is an outer layer, 22 is an intermediate layer, 23 is an inner layer, 31 is a core material, and 32 is a core material. Reference numeral 33 denotes a heat-adhesive resin layer having easy peelability of the tape material, and reference numeral 33 denotes a heat-adhesive resin layer of the tape material.

FIG. 1 is a perspective view of a first embodiment of a packaging bag according to the present invention, and FIG. 2 is an enlarged sectional view of a main part of FIG.
The packaging bag 1 is formed by folding a rectangular bag body material 2 having a heat-adhesive resin layer on the inner layer 23 with the inner layer 23 inside, with a gap opened so that a pair of opposing ends do not overlap. A tape material 3 having a heat-adhesive resin layer wider than the gap and having a heat-adhesive resin layer on both sides thereof is heat-bonded to the inner surface of the provided portion at both side edges of the tape material 3 in parallel with the pair of opposite ends. A packaging bag made of a tubular body having envelope-shaped seal portions 5 and 6, and formed into a shape having end seal portions 4 and 4 by heat-bonding openings at both ends of the tubular body, The heat-adhesive resin layer on the surface of the tape material 3 that is heat-adhered to the inner layer of the bag body 2 at the portion where the gap is provided is made of a heat-adhesive resin layer 32 having easy peelability. The seal width of the two envelope-shaped seal portions 5, 6 is smaller than the seal width of the end-portion seal portions 4, 4, and the seal width of the envelope-shaped seal portion 5 is smaller than that of the envelope-shaped seal portion. 6 is smaller than the seal width.

FIG. 3 is a diagram showing a main layer structure of a first embodiment of a packaging bag according to the present invention. The bag body 2 of the packaging bag 1 is made of a 15 μm biaxially stretched polyamide film forming an outer layer 21 and isocyanate. Anchor coating agent for system compounds (not shown)
After coating, 25 μm high-pressure low-density polyethylene forming the inner layer 23 was extruded and applied using a T-die. The tape material 3 of the packaging bag 1 is made of a mixed resin of a crystalline propylene-ethylene random copolymer / high-pressure low-density polyethylene / ethylene propylene rubber in a ratio of 48/50/2% by weight and a high-pressure low-density polyethylene. Coextruded 2
A 35 μm unstretched film having a layer structure, wherein the mixed resin layer of the unstretched film having the two-layer structure is a heat-adhesive resin layer 32 having an easy peeling property of the tape material 3, The high-pressure low-density polyethylene layer constitutes another thermo-adhesive resin layer 33, and the inner layer 23 of the bag body 2 and the thermo-adhesive resin layer 32 of the tape material 3 having easy peelability are formed by the above-mentioned method. They are thermally bonded at the envelope-shaped seal portions 5 and 6.

Although not shown, the packaging bag 1 contains cooked noodles such as rice noodles, fried noodles, and fried udon, and foods such as meat bean, anman, sh ウ mai, dumplings, hamburgers, and hot dogs. It is a type that is cooked for a predetermined time in a microwave oven as it is.

FIG. 4 is a perspective view of the packaging bag according to the first embodiment of the present invention shown in FIG. 1 during heating and cooking. The packaging bag 1 has the structure shown in FIGS. The pressure relief portion is designed in the envelope-shaped seal portion 5. When the packaging bag 1 containing the food is placed in a microwave oven and cooked, steam generated from the food and air in the packaging bag are thermally expanded, the internal pressure is increased, and the packaging bag 1 is swollen into a bread pan. At the same time, between the inner layer 23 of the bag body 2 at a position substantially at the center of the envelope-shaped seal portions 5 and 6 and the easily peelable thermal adhesive resin layer 32 of the tape material 3 or the easily peelable thermal adhesive resin layer 32 And delamination 8 or 8 ′ by delamination or cohesive failure
Starts to occur from the inside of the packaging bag 1. Eventually, the packaging bag 1 advances faster since the peeling 8 of the envelope-shaped seal portion 5 is narrower than the peeling 8 'of the envelope-shaped seal portion 6 and reaches the outer end of the envelope-shaped seal portion 5. The internal pressure is released to prevent the packaging bag 1 from breaking. On the other hand, the food stored in the packaging bag 1 can be steamed until the peeling 8 generated on the envelope-shaped seal portion 5 reaches the outer end portion of the envelope-shaped seal portion 5, so that a better taste can be obtained. Is also possible.

FIG. 5 is a diagram showing the main layer structure of a packaging bag according to a second embodiment of the present invention. The bag body 2 'of the packaging bag 1' is a 15 μm biaxially stretched polyamide film forming the outer layer 21. And a 40 μm unstretched polypropylene film forming an inner layer 23 and a laminate formed by laminating a two-component reactive polyurethane adhesive (not shown) by a well-known dry lamination method. Tape material 3 'forms the core material 31
55/43/2 of crystalline propylene-ethylene random copolymer / high-pressure low-density polyethylene / ethylene propylene rubber on one side of a 15 μm biaxially stretched polyamide film
A 25 μm unstretched film made of a mixed resin in a ratio of 2% by weight, and a 25 μm unstretched polypropylene film on the other surface, using a two-component reaction type polyurethane adhesive (not shown) to dry lamination. It is composed of a laminate bonded by a method. In the tape material 3 ′, a 25 μm unstretched film made of the mixed resin constitutes the heat-adhesive resin layer 32 having easy peelability of the tape material 3 ′, and the 25 μm unstretched polypropylene film is the other. A thermo-adhesive resin layer 33 is formed, and the inner layer 23 of the bag body material 2 'and the thermo-adhesive resin layer 32 having easy peelability of the tape material 3' are heat-bonded by the envelope-shaped seal portions 5, 6. Have been. The packaging bag 1 'thus configured can also be used as a retort packaging bag (a packaging bag capable of high-temperature and high-pressure sterilization).

FIG. 6 is a diagram showing a main layer structure of a third embodiment of the packaging bag according to the present invention, wherein a bag main body 2 "of the packaging bag 1" is a 15 μm biaxially stretched polyamide film forming the outer layer 21. And a 12 μm biaxially stretched polyterephthalate film having a silicon oxide vapor-deposited layer forming the intermediate layer 22 and a 40 μm unstretched polypropylene film forming the inner layer 23 are successively formed using a two-component reactive polyurethane adhesive (not shown). And a laminated body (a silicon oxide deposited layer is a biaxially stretched polyamide film side) bonded by a well-known dry lamination method, and the tape material 3 "of the packaging bag 1" is made of silicon oxide which forms the core material 31. The ratio of 55/43/2% by weight of crystalline propylene-ethylene random copolymer / high-pressure low-density polyethylene / ethylene propylene rubber was applied to the evaporation surface of a 12 μm biaxially stretched polyterephthalate film having an evaporation layer. A mixed resin of
25μm unstretched film and 25μm
Of the non-stretched polypropylene film is bonded by a known dry lamination method using a two-component reactive polyurethane adhesive (not shown). In the tape material 3 ″, a 25 μm
Non-stretched film constitutes a heat-adhesive resin layer 32 having easy peelability of the tape material 3 ″, and the 25 μm unstretched polypropylene film constitutes another heat-adhesive resin layer 33,
The inner layer 23 of the bag body material 2 "and the easily peelable thermo-adhesive resin layer 32 of the tape material 3" are formed by the envelope-shaped seal portions 5, 6.
Heat bonded. The packaging bag 1 "thus configured can be used as a packaging bag having excellent gas barrier properties and also as a retort packaging bag (a packaging bag capable of high-temperature and high-pressure sterilization).

In the description so far, the seal width of the envelope-shaped seal portions 5, 6 is smaller than the seal width of the end-portion seal portions 4, 4, and the seal width of the envelope-shaped seal portion 5 is smaller than the envelope width. Although the embodiment in which the seal width is smaller than the seal width of the seal portion 6 is used, the seal width of the envelope-shaped seal portions 5 and 6 may be the same, or the envelope width of the envelope-shaped seal portions 5 and 6 may be the same. The seal width may be the same as the seal width of the end seal portions 4 and 4.

[0030]

The present invention will be described in more detail with reference to the following examples. Example 1 Outside dimensions filled with cooked roasted potatoes (250 g) are 140 x 23
0mm, seal width of end seal is 10mm, gap of bag body is
Fifty packaging bags of the first embodiment of the present invention, each of which had a width of 10 mm, a tape material of 30 mm, and one of the envelope-shaped seal portions having a seal width of 5 mm and the other seal width of 8 mm, were produced. This was heated in a microwave oven (rated high-frequency output 500 W) for 3 minutes. 2 minutes ± 15 seconds after the start of heating all 50 bags, the internal pressure rises, so that all of them can be peeled off from the approximate center of the 5-mm-wide envelope seal to release internal pressure and prevent bag breakage. Was. Further, the taste of the contents was not impaired. Example 2 Outside dimensions filled with cooked hamburger (75 g) are 115 x 17
0mm, seal width of end seal is 10mm, gap of bag body is
Fifty packaging bags according to the second embodiment of the present invention, each of which had a width of 10 mm, a tape material of 30 mm, one seal width of an envelope-shaped seal portion of 5 mm, and the other seal width of 8 mm, were produced. This was placed in a retort pot and sterilized by heating at 120 ° C. for 30 minutes.
Good results were obtained with no abnormalities such as bag breakage in all 50 bags. This was heated in a microwave oven (rated high-frequency output 500 W) for 90 seconds. Due to the increase of the internal pressure 40 ± 10 seconds after the heating of all 50 bags was started, all were peeled off from the approximate center of the 5 mm-wide envelope-shaped seal to release the internal pressure and prevent the bag from breaking. . Further, the taste of the contents was not impaired.

[0031]

As described above, the packaging bag of the present invention can completely seal a cooked or semi-cooked food or the like, and can use a microwave oven with the food stored in the packaging bag. Heat cooking can be performed, and steam generated during the cooking after a predetermined time has elapsed since the start of the heating cooking, and air that has been thermally expanded in the packaging bag can be released to prevent the bag from being broken, and steam generated during the heating cooking can be prevented. This has the effect of steaming the food stored in the packaging bag until the thermally expanded air in the packaging bag is released. In addition, since the easily peelable thermo-adhesive resin layer is used for the tape material, the cost of the packaging bag can be reduced as compared with the case where it is conventionally used for the inner layer of the packaging bag, and it can also cope with high-temperature heat sterilization. Such an effect is also achieved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of a packaging bag according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is a main part layer configuration diagram of the first embodiment of the packaging bag according to the present invention.

FIG. 4 is a perspective view of the first embodiment of the packaging bag according to the present invention during heating cooking.

FIG. 5 is a main part layer configuration diagram of a second embodiment of the packaging bag according to the present invention.

FIG. 6 is a main part layer configuration diagram of a third embodiment of the packaging bag according to the present invention.

[Explanation of symbols]

1, 1 ', 1 "packaging bag 2, 2', 2" bag body material 3, 3 ', 3 "tape material 4 end seal portion 5, 6 envelope-shaped seal portion 8, 8' peeling portion 21 outer layer 22 intermediate Layer 23 Inner layer 31 Core material 32 Thermo-adhesive resin layer with easy peelability of tape material 33 Thermo-adhesive resin layer of tape material

Claims (3)

[Claims] 1. A rectangular bag body material having a heat-adhesive resin layer as an inner layer is folded with the inner layer being on the inner side in a state where a gap is opened so that a pair of opposite ends do not overlap with each other, and the gap is provided. A tape material wider than the gap and having a heat-adhesive resin layer on both surfaces is thermally bonded to the inner surface of the portion at both side edges of the tape material in parallel to the pair of opposite ends, and two envelope-shaped seal portions are provided. In a packaging bag made into a shape having a cylindrical body having an end seal portion by thermally bonding the openings at both ends of the cylindrical body, the gap of the bag body material of the tape material is provided. A heat-adhesive resin layer on the surface that is heat-adhered to the inner layer at the site where the heat-adhesive resin layer has easy peelability. 2. The packaging bag according to claim 1, wherein a sealing width of at least one of the two envelope-shaped seal portions is smaller than a seal width of the end seal portion. Packaging bag. 3. The packaging bag according to claim 1, wherein the heat-adhesive resin layer on the surface of the tape material that is heat-bonded to the inner layer of the bag body material is a mixed resin of a polypropylene resin, a polyethylene resin, and an olefin copolymer rubber. The packaging bag according to claim 1, wherein the packaging bag comprises: