JPH10193518A - Plastic bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable realization of a bag which is excellent in freestanding stability, which can be subjected to heat cooking by a microwave oven with a bag body kept as it is and which is free from escape of a content liquid or the like, by a method wherein a plastic material of which the surface has a non-thermal-adhesion property and the inner surface a thermal adhesion property is folded, the opposed parts having the thermal adhesion property are heat-bonded and the bottom part is shaped like the bottom of a ship. SOLUTION: Front and rear walls 1 and 2 each of which has a surface (p) having a non- thermal-adhesion property and an inner surface (q) having a thermal-adhesion property are put on each other with the inner surfaces (q) opposed. A bottom wall 4 folded in the shape of an inverted V with the inner surface (q) outside and having notch parts 3 in both side edges is inserted into a lower end part between the front and rear walls, and the walls 1, 2 and 4 are laminated. A plastic bag A is manufactured in such a manner that side seal parts 5 are formed by heating the laminated parts of the walls 1 and 2, 1 and 4 and 2 and 4 in both side edge parts of these walls, seal parts 6 are formed by heating the laminated parts of the walls 1 and 2 through the intermediary of the notch parts 3, a bottom seal part 7 is formed by heating the laminated parts of the walls 1 and 4, and 2 and 4, in the bottom edge part and oblique seal parts 8 are formed in the laminated parts of the walls 1 and 4, and 2 and 4, from parts of the side top parts (r) of the wall 4 toward the seal part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic bag, and more particularly to a plastic bag suitable for a microwave oven which can be cooked by a microwave oven.

[0002]

2. Description of the Related Art Conventionally, various forms of plastic bags suitable for microwave ovens have been developed and proposed. For example, a breathable packaging bag having a configuration in which a seal portion such as a maze is provided on one side or more of the bag body in order to transmit water vapor or the like during cooking by heating in a microwave oven is known. I have. Similarly, in order to transmit water vapor and the like at the time of cooking by heating in a microwave oven,
There is also known a breathable packaging bag formed by punching a part of a bag body.

[0003]

However, when the above-described air-permeable packaging bag is placed in a microwave oven and cooked by heating, the bag lacks independence stability, and the bag in the microwave oven lacks stability. However, there is a problem that it is difficult to heat cook in a microwave oven while keeping the packaging bag as it is. Even if it could be cooked, the nutrients and juices contained in it would flow out of the contents during cooking, and it would be good while this stayed in the bag, but gradually the nutrients, Liquid such as juice increases, for example, when the bag is a flat pouch or the like,
From a seal or hole etc. like a maze provided in the bag,
It will be drained out of the bag. In this case, the inside of the microwave oven is contaminated, and after use, the inside of the microwave oven must be cleaned, which makes the cleaning and the like extremely troublesome. Moreover, if liquids such as nutrients and juice contained in the contents leak out, the flavor of the contents is impaired, which is not preferable. Therefore, the present invention provides a microwave oven that can be cooked by a microwave as it is in a bag, and has excellent self-standing stability without draining liquids flowing out of contents and the like. Is to provide a packaging bag having the following.

[0004]

As a result of various studies to solve the above problems, the present inventor has found that the front wall and the rear wall have a non-heat-adhesive surface and a heat-adhesive inner surface. A wall is overlapped with its inner surface having thermal adhesion facing the same, and further, at the lower end between the two, the outer surface has non-thermal adhesion, the inner surface has thermal adhesion, and Fold it into an inverted V-shape with its inner surface outside, and insert a bottom wall having cutouts on both side edges. At both side edges, a front wall and a rear wall, a front wall and a bottom wall, and a rear wall Heat seal the bottom wall to form a side seal portion, and form a heat seal portion between the front wall and the rear wall through the cutout portion, and At the bottom edge, the front wall and the bottom wall, and the rear wall and the bottom wall are heat-sealed to form a bottom seal portion. A diagonal seal portion is formed from the top portion on both sides of the mold toward the bottom seal portion to produce a plastic bag having a bottom portion of a boat bottom shape. After filling and packaging the contents such as hamburger, and freezing and preserving, the upper end seal part was removed and the product was cooked by microwave oven as it was.
The bag can be heated and cooked in the microwave as it is without the bag turning over in the microwave, and the drainage of nutrients, juices and other liquids contained in the contents etc. Thus, the present invention has been completed by finding that a plastic bag having microwave oven suitability can be produced extremely favorably.

That is, according to the present invention, a front wall and a rear wall having a non-thermal adhesive surface and a thermal adhesive inner surface are overlapped with the thermal adhesive inner surface facing each other. At the lower end between the two, the outer surface has non-thermal bonding, the inner surface has thermal bonding, and the inner surface is outside, and it is folded into an inverted V-shape, and further cut on both sides. A bottom wall having a notch is inserted, and at both side edges, the front wall and the rear wall, the front wall and the bottom wall, and the rear wall and the bottom wall are heat-sealed to form a side seal portion. Forming a heat seal between the front wall and the rear wall through the notch of
At the bottom edge, the front wall and the bottom wall and the rear wall and the bottom wall are heat-sealed to form a bottom seal portion. The present invention relates to a plastic bag for a microwave oven, wherein a diagonal seal portion is formed from the bottom to the bottom seal portion.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. First, the configuration of the plastic bag according to the present invention will be described with reference to the drawings by exemplifying specific examples. FIGS. 1 to 4 are cross-sectional views showing an example of the plastic bag according to the present invention. Or a plan view,
Specifically, FIG. 1 is a schematic cross-sectional view illustrating a layer configuration of a plastic bag according to the present invention, and FIG. 2 is a schematic plan view illustrating a configuration of the plastic bag according to the present invention. FIG. 3 is a schematic plan view showing the configuration of another embodiment of the plastic bag according to the present invention, and FIG. 4 is a cross-sectional view taken along line YY ′ of the plastic bag according to the present invention shown in FIG. It is.

First, in the present invention, as shown in FIG. 1, a plastic bag according to the present invention has a front wall 1 having a non-heat-adhesive surface and an inner surface q having a heat-adhesive front wall 1 and a rear wall 1. The wall 2 is overlapped with the heat-adhesive inner surfaces q and q facing each other, and further, at the lower end between the two 1 and 2, the outer surface p has non-heat-adhesive properties and the inner surface q has A bottom wall 4 having thermal adhesiveness, folded in an inverted V-shape with its inner surface q outside, and further with cutouts 3, 3, 3, 3 (shown in FIG. 2) on both side edges thereof Into the front wall 1,
The rear wall 2 and the bottom wall 4 are overlapped. Next, in the present invention, as shown in FIG.
And the bottom wall 4 is overlapped, and heat seal is provided at the overlapping portions of the front wall 1 and the rear wall 2, the front wall 1 and the bottom wall 4, and the rear wall 2 and the bottom wall 4 at both side edges. To form the side seal portions 5 and 5,
Heat sealing is performed at the overlapping portion of the front wall 1 and the rear wall 2 via the third, third, and third seals 6 and 6, and at the bottom edge thereof, the heat sealing is performed. Heat sealing is performed at the bottom wall 4 and at the overlapping portion of the rear wall 2 and the bottom wall 4 to form a bottom seal portion 7, and further, the top portions r, r on both sides of the inverted V-shaped bottom wall 4.
The diagonal seal portions 8, 8 are formed at the overlapping portions of the front wall 1 and the bottom wall 4 and the rear wall 2 and the bottom wall 4 from the portion toward the bottom seal portion 7 according to the present invention. Plastic bag A
Can be manufactured. In the above, each seal is symmetrically formed on the opposite side. In the above, in order to improve the self-sustainability of the plastic bag according to the present invention, the angles α, α formed by the bottom seal portion 7 and the oblique seal portion 8 are α = 30. It is desirably in the range of about 60 degrees to about 60 degrees.

Next, in the present invention, another example of the plastic bag according to the present invention will be described. As shown in FIGS. 3 and 4, first, as shown in FIG. When the plastic bag of the present invention is manufactured, an unsealing portion is formed of a convex portion 9 and a concave portion 10 which are previously fitted to the inner surfaces of the front wall 1 and the rear wall 2 at positions corresponding to the vicinity of the opening of the plastic bag. The chuck tape 11 is attached, and thereafter, the plastic bag B according to the present invention can be manufactured in the same manner as described above. In addition,
3 and 4, 1, 2, 3, 4, 5, 6, 7, 8,
α and the like have the same meaning as described above.

In the present invention, the plastic bag exemplified above is an example, and the present invention is not limited thereto. For example, although not shown in the present invention, As described above, the front wall, the rear wall, the bottom wall, and the like are not individually formed in a single sheet, but are formed continuously using the continuous sheet and the front wall, the bottom wall, and the rear wall. And the portion corresponding to the bottom wall is inverted V
It can be folded into a letter shape to produce a plastic bag. Further, in the present invention, as the form of the plastic bag according to the present invention, although not shown,
Alternatively, any form such as a horizontally long one can be manufactured, but in the present invention, in consideration of preventing the bag from rolling over when placed in a microwave oven, a plastic bag is considered. It is preferable that the length of the plastic bag is longer than the vertical direction and that the bottom of the plastic bag is a boat bottom type.

Next, in the present invention, a method for filling and packaging the contents in the plastic bag according to the present invention as described above will be described. As shown in FIG.
The plastic bag shown in FIG. 4 will be described as an example. The plastic bag B manufactured as described above is filled with the contents 12 through the opening, and then the opening is heat sealed to seal the upper end. By forming 13, a packaged product C using the plastic bag according to the present invention can be manufactured. 5, 1, 2, 3, 4, 6, 7, 8, 9,
10, 11, α, etc. have the same meaning as described above. Thus,
In the present invention, the above-mentioned packaged product C is usually
When stored frozen and eaten, as it is, or with its upper end seal portion 13 removed using scissors or the like,
Further, in a state where the concave and convex fitting of the opening chuck tape 11 is partially released, for example, when the contents 12 are a hamburger or the like, the contents are heated and cooked in a microwave oven, and then the opening chuck tape 11 is opened. -Release the concave and convex fitting of the step 11 and open it,
The contents 12 can be taken out and eaten. In addition, the plastic bag according to the present invention is not filled with the contents as described above, and the plastic bag itself is distributed and sold. Is filled and frozen at each home, stored refrigerated, and eaten in a microwave oven in the same manner as described above, with the opening and closing of the opening and closing of the opening zipper tape partially released. The concave / convex fitting of the post-opening zipper tape is released to open and the contents can be taken out and eaten.

Next, in the plastic bag according to the present invention as described above, the materials constituting the front wall, the rear wall, the bottom wall, and the like will be described. Constituent resin films or sheets can be used, and specifically, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, Ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid or methacrylic acid copolymer, methylpentene polymer, polybutene resin, polyvinyl chloride resin, polyvinyl acetate Resin, polyvinylidene chloride resin, vinyl chloride-vinylidene chloride copolymer, poly (meta Acrylic resins, polyacrylonitrile resins, polystyrene resins, acrylonitrile - styrene copolymer (AS resin), acrylonitrile - butadiene - styrene copolymer (ABS resin),
Polyester resin, polyamide resin, polycarbonate resin, polyvinyl alcohol resin, ethylene
Saponified vinyl acetate copolymer, fluorine-based resin, diene-based resin, polyacetal-based resin, polyurethane-based resin,
It can be arbitrarily selected from known resin films or sheets such as nitrocellulose and the like.
In addition, for example, a film such as cellophane, synthetic paper, or the like can be used. In the present invention, any of the above-mentioned resin films or sheets that have not been stretched or stretched uniaxially or biaxially can be used. The thickness is arbitrary, but is from several μm to 3 μm.
It can be used by selecting from a range of about 00 μm.
Furthermore, in the present invention, as the resin film or sheet, extrusion film formation, inflation film formation, and
Any property such as a thin film may be used.

Further, in the plastic bag according to the present invention, the material constituting the front wall, the rear wall, the bottom wall and the like is a laminated material obtained by arbitrarily laminating the above resin film or sheet. Etc. can be used. To describe the laminated material in more detail, as a material constituting the laminated material, for example, usually, as a base film constituting a basic material constituting a plastic bag, mechanical, physical, chemical, A resin film or sheet having excellent properties in others and the like, and particularly having strength and toughness and having heat resistance can be used. Specifically, for example, polyester resin,
It is possible to use a film or sheet of a tough resin such as polyamide resin, polyaramid resin, polyolefin resin, polycarbonate resin, polyacetal resin, fluorine resin, etc. it can. Thus, as the resin film or sheet, any one of an unstretched film and a stretched film stretched in a uniaxial or biaxial direction can be used. The thickness of the film is 5 μm to 10
It is desirably about 0 μm, preferably about 10 μm to 50 μm. In the present invention, the base film as described above is subjected to, for example, front printing or back printing by printing a desired printing pattern such as a character, a figure, a symbol, a picture, or a pattern by a normal printing method. It may be. Further, in the base film as described above, for example, polyolefin-based resin, or polyester-based resin or the like, if it itself has a heat-sealing property, it is utilized in the present invention. Such a plastic bag can be manufactured.

Next, in the present invention, as the base film, for example, various paper base materials constituting a paper layer can be used.
The paper base material is provided with shapeability, bending resistance, rigidity, etc., for example, strong size bleached or unbleached paper base material, or pure white roll paper, kraft paper, paperboard, A paper substrate such as a processed paper or the like can be used. In the above, as the paper base material constituting the paper layer, a basis weight of about 20 to
600 g / m ² , preferably about 30 to 4 basis weight
It is desirable to use a material of about 50 g / m ² . Needless to say, in the present invention, a paper base constituting the paper layer and various resin films or sheets as the base films mentioned above can be used in combination.

Next, in the present invention, when manufacturing the laminated material according to the present invention, the innermost surface thereof is manufactured by heat-sealing the innermost surface thereof to form a seal portion. Since the bag, the innermost layer of the laminated material according to the present invention,
That is, it is desirable to use a resin film or sheet having heat sealability. The heat-sealing resin film may be any film that can be melted by heat and fused together, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, and wire. Low-density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer Polyolefin resins such as polymers, ethylene-propylene copolymers, methylpentene polymers, polybutene polymers, polyethylene or polypropylene are converted to unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and maleic anhydride. Acid-modified acid-modified polyolefin resin, polyvinyl acetate Le resins, poly (meth) acrylic resins, polyvinyl chloride resins, resins and other such film or sheet - may be used and. Thus, the above-mentioned film or sheet can be used in a state of a coating film of a composition containing the resin. The thickness of the film or film or sheet is 5 μm
To about 300 μm, preferably 10 μm to 10 μm.
About 0 μm is desirable. By the way, in the present invention, the outermost layer constituting the laminated material is desirably non-heat-adhesive, whereby a self-supporting or boat-bottom type plastic bag can be manufactured. .

Further, in the present invention, the above-mentioned
As a film of the resin having a sealing property, a film or sheet of an ethylene-α-olefin copolymer polymerized by using a metallocene catalyst can be used in the same manner. Specifically, as a film or sheet of an ethylene-α-olefin copolymer polymerized using a metallocene catalyst, for example, a metallocene complex such as a catalyst formed by a combination of zirconocene dichloride and methylalumoxane and alumoxane A catalyst or catalyst of the combination, that is, a film or sheet of an ethylene-α-olefin copolymer obtained by polymerization using a metallocene catalyst can be used. The metallocene catalyst has a non-uniform active site and is called a multi-site catalyst, whereas the existing catalyst is called a single-site catalyst because the active site is uniform. For example, Mitsubishi Chemical Corporation's product name "Kernel", Mitsui Petrochemical Industry Co., Ltd. product name "Evolu", USA, Exxon Chemical (EXX)
"EXACT" (trade name, manufactured by ON CHEMICAL), Dow Chemical, USA
"Affinity- (AF)
FINITY), brand name "ENGAGE (ENGAG)
E) ethylene-polymerized using a metallocene catalyst such as
An α-olefin copolymer film can be used. Thus, in the present invention, the ethylene-α.
The olefin copolymer film can be used in the form of a coating film or the like made of a composition containing the resin. The thickness of the film or film is 5
It is preferably about μm to 300 μm, preferably about 10 μm to 100 μm. In the present invention, when a film or sheet of an ethylene-α-olefin copolymer polymerized using a metallocene catalyst is used as the heat-sealing resin film as described above,
This has the advantage that low-temperature heat sealability is possible when manufacturing a bag.

Further, when producing the laminated material according to the present invention, a substrate having a barrier property can be further used. , The property of blocking light such as sunlight, or water vapor,
A material having the property of impermeable to water, gas, and the like can be used, and may be a single base material or a composite base material obtained by combining two or more types of base materials. Specifically, for example, silicon oxide having a barrier property, a resin film having a deposited film of an inorganic oxide such as aluminum oxide, low-density polyethylene having a barrier property such as water vapor and water, medium-density polyethylene, and high-density polyethylene have a high barrier property. Film or sheet of resin such as high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, polyvinylidene chloride having a gas barrier property, polyvinyl alcohol, ethylene-vinyl acetate copolymer Films or sheets of various colored resins having light-shielding properties obtained by adding a colorant such as a pigment to the resin and other desired additives and kneading to form a film. Etc. can be used.
These materials can be used alone or in combination of two or more. The thickness of the above-mentioned film or sheet is arbitrary, but usually 5 μm to 300 μm.
μm, more preferably about 10 μm to 100 μm. Further, in the above, as the vapor deposited film of the inorganic oxide, a film having a thickness of about 100 to 2000 mm can be used. Examples of the resin film supporting the above-mentioned vapor-deposited film include a polyester film, a polyamide film, a polyolefin film, a polyvinyl chloride film, a polycarbonate film, a polyvinylidene chloride film, a polyvinyl alcohol film, and an ethylene-acetic acid film. Saponified vinyl copolymer films and the like can be used.

Further, in the above, as the inorganic oxide constituting the above-mentioned inorganic oxide vapor-deposited film layer, for example, silicon oxide (SiO _x ), aluminum oxide, indium oxide, tin oxide, zirconium oxide or the like is used. can do. Furthermore, in the present invention, the inorganic oxide may be a mixture of silicon monoxide and silicon dioxide, or a mixture of silicon oxide and aluminum oxide. In the present invention, as a method of forming the inorganic oxide thin film layer, the thin film layer is formed by forming a vapor deposition film by a vacuum vapor deposition method such as an ion beam method or an electron beam method, or a sputtering method. be able to. In the above description, the thickness of the inorganic oxide thin film layer is usually preferably about 100 ° to 2000 ° in order to obtain a sufficient barrier property.
It is desirable to be around {1500}. In the above, when the thickness of the inorganic oxide thin film layer exceeds 1500 °, in particular, 2
If it exceeds 000 °, cracks and the like are apt to be formed in the thin film layer of the inorganic oxide, and there is a risk that the barrier property may be reduced due to the warp, and the material cost may be increased.

Next, a method of manufacturing the laminated material according to the present invention using the above-mentioned materials in the present invention will be described. How to laminate,
For example, wet lamination, dry lamination, solventless dry lamination, extrusion lamination, T-die coextrusion molding, coextrusion lamination, inflation, etc. be able to. Thus, in the present invention, when performing the above lamination, if necessary, a pretreatment such as a corona treatment or an ozone treatment can be applied to the film. (Urethane),
For anchoring agents such as polyethyleneimine, polybutadiene, and organotitanium, or for laminates such as polyurethane, polyacryl, polyester, epoxy, polyvinyl acetate, cellulose, etc. Known anchor coating agents such as adhesives, adhesives and the like can be used.

By the way, in the above-mentioned method of manufacturing a laminated material, the extruded resin constituting the adhesive resin layer at the time of extruding and laminating is, for example, polyethylene,
Ethylene-α-olefin copolymer, polypropylene,
Copolymers of ethylene and unsaturated carboxylic acids such as polybutene, polyisobutene, polyisobutylene, polybutadiene, polyisoprene, ethylene-methacrylic acid copolymer, or ethylene-acrylic acid copolymer, or acid-modified polyolefins obtained by modifying them A series resin, an ethylene-ethyl acrylate copolymer, an ionomer resin, an ethylene-vinyl acetate copolymer, and the like can be used. Further, in the present invention, as the adhesive constituting the adhesive layer at the time of dry lamination, specifically,
Two-component curable urethane adhesives, polyester urethane adhesives, polyether urethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, polyvinyl acetate adhesives used in dry laminates, etc. An adhesive, an epoxy-based adhesive, a rubber-based adhesive, and the like can be used.

Next, in the present invention, as a method of heat sealing when producing the plastic bag according to the present invention, for example, a bar seal, a rotating roll seal, a belt seal, or the like is used. , Impulse seal, high frequency seal, ultrasonic seal
Can be performed by a known method such as

Next, in the present invention, as an opening zipper tape comprising concave and convex portions to be fitted and recessed and used for manufacturing the plastic bag according to the present invention, for example, a sectional view shown in FIG. As shown, the flat support 20,
20 'is provided with a convex portion 21 and a concave portion 22, respectively. A convex-concave fitting body portion can be formed by the convex portion 21 and the concave portion 22, and a hook-type chuck tape D having resealability is used. can do. In the present invention, as the opening chuck tape, although not shown, an opening chuck tape manufactured by extrusion molding with a small number of flat supporting portions can be used. In this case, the front wall or the rear wall can be used. Can be directly extruded and formed on the inner surface of the front wall or the rear wall. As the opening zipper tape as described above, it is preferable to use a zipper tape which is heat-sealed with the innermost surface of the laminated material constituting the plastic bag and has adhesiveness. And polyethylene-based resins such as linear (linear) low-density polyethylene, medium-density polyethylene, and high-density polyethylene, polypropylene-based resins, ionomer resins, ethylene-methacrylic acid copolymers, and ethylene-vinyl acetate copolymers. -Toshi-
It is desirable to use a resin-made molded product having a property of lubrication. For example, the innermost layer of the laminated material used when manufacturing the plastic bag according to the present invention is used.
Heat-sealing resin film
When a non-stretched polypropylene resin film having reversibility is used, in the present invention, as an opening zipper tape, a heat sheet of the innermost layer constituting the laminated material is used.
It is preferable to use a resin of the same quality as a non-stretched polypropylene resin film having heat sealability as a resilient film, and to use a polypropylene resin molded article molded from the resin.

According to the present invention, when manufacturing the plastic bag according to the present invention, an opening chuck tape is provided on a front wall and a rear wall of a portion corresponding to a predetermined portion near the above-mentioned opening. To the innermost layer of each
It can be fixed by sealing. In the above,
As a method of heat sealing, for example, a bar seal,
Rotary roll seal, belt seal, impulse seal,
It can be performed by a known method such as a high-frequency seal or an ultrasonic seal.

In the present invention, the plastic bag manufactured as described above is filled and packed with various foods and the like.
It can be used as a bag for a microwave oven.

[0024]

The present invention will be described more specifically with reference to the following examples. Example 1 On one surface of a biaxially stretched nylon film having a thickness of 15 μm,
3 g / m ² (dry) of liquid-curable polyurethane adhesive
Then, a 50 μm-thick unstretched polypropylene film is dry-laminated on the coated surface, and the front wall,
Laminated materials constituting the rear wall and the bottom wall were manufactured. next,
Using the laminated material produced above, first, a laminated material constituting a front wall and a rear wall having a size of 15 cm in length and 22 cm in width, 2
One sheet, a laminated material constituting the bottom of 10 cm in length and 22 cm in width, and one sheet were prepared. Further, the above-mentioned laminated material forming the front wall and the rear wall was bonded to the inner surface of a portion corresponding to the vicinity of the opening of both of them by opening and closing zipper tape. Next, the front wall and the rear wall are overlapped with the unstretched polypropylene film facing each other, and further, at the lower ends thereof, the inverted V-shape is formed so that the unstretched polypropylene film surface becomes the surface. And a bottom wall having notches formed at both end portions thereof is interposed. Then, the laminated material forming the front wall and the rear wall and the laminated material forming the bottom portion are separated into peripheral end portions thereof. Heat the side and bottom of
A self-supporting, boat-bottomed plastic bag was produced by tosealing. In the plastic bag manufactured above,
The angle formed by the bottom seal portion and the oblique seal portion was 45 degrees. By the way, a hamburger was filled from the opening of the plastic bag manufactured as described above, and then the opening was heat-sealed to manufacture a packaged product. When the above packaged product was stored frozen and eaten, the seal at the opening was removed, and then the product was heated and cooked in a microwave oven. As a result, the hamburg could be eaten very well. In the above, instead of the biaxially stretched nylon film having a thickness of 15 μm, a biaxially stretched nylon film having a thickness of 25 μm was used, and a laminated material forming the front wall and the rear wall was manufactured in the same manner as above. On the other hand, as the bottom wall, a laminated material is manufactured in the same manner as described above, using a biaxially stretched nylon film having a thickness of 15 μm as described above. By making the thickness of the laminated material constituting the wall thicker than the thickness of the laminated material constituting the bottom wall, a plastic bag capable of further improving the independence of the bag body could be manufactured.

Example 2 A two-part curable polyurethane-based adhesive was applied at 3 g / m ^{2 on the} silicon oxide deposited film surface of a 12 μm thick biaxially stretched polyethylene terephthalate film having a silicon oxide deposited film.
(Dry) coating and then 15 μm thick
And then dry laminating the biaxially stretched nylon film of 3 g / m ² (dry) on the surface of the biaxially stretched nylon film. Then, a non-stretched polypropylene film having a thickness of 50 μm was dry-laminated to produce a laminated material. Next, the plastic bag of the present invention was manufactured using the laminated material manufactured as described above and in the same manner as described in Example 1 above. Furthermore, the hamburger could be eaten very well using the above plastic bag in the same manner as in Example 1 described above.

[0026]

As is apparent from the above description, according to the present invention, a front wall and a rear wall each having a non-thermal adhesive surface and an inner surface having a thermal adhesive property are formed on the inner surface having the thermal adhesive property. The outer surface has non-heat bonding property, the inner surface has heat bonding property, and the inner surface is outside at the lower end portion between the two to form an inverted V-shape. The bottom wall having notches on both side edges is inserted, and the front wall and the rear wall, the front wall and the bottom wall, and the rear wall and the bottom wall are heat-sealed at the both side edges. A side seal portion is formed, a seal portion is formed by heat sealing the front wall and the rear wall through the notch, and the front edge and the bottom wall are formed at the bottom edge. And a heat seal between the rear wall and the bottom wall to form a bottom seal portion, and further, from the tops on both sides of the inverted V-shape constituting the bottom wall to the bottom seal portion. A diagonal seal is formed to produce a plastic bag having a boat bottom type bottom, and the plastic bag is filled with contents such as a hamburger. After freezing and storage, the upper end seal is removed and the product is heated and cooked in a microwave oven as it is. It has excellent self-standing stability, the bag does not roll over in the microwave, It can be cooked in a microwave oven, and there is no drainage of liquids such as nutrients and juices contained in the contents, and it is possible to produce a plastic bag having microwave oven suitability very well. Things.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a layer configuration of a plastic bag according to the present invention.

FIG. 2 is a schematic plan view showing an example of the configuration of a plastic bag according to the present invention.

FIG. 3 is a schematic plan view showing the configuration of another embodiment of the plastic bag according to the present invention.

FIG. 4 shows Y ₁ − of the plastic bag shown in FIG.
It is a sectional view taken along the Y ₁ '.

FIG. 5 is a schematic plan view showing a configuration in which the plastic bag shown in FIGS. 3 and 4 is used and contents are filled and packaged.

FIG. 6 is a schematic cross-sectional view showing a configuration of an opening chuck tape according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front wall 2 Rear wall 3 Cut-out part 4 Bottom wall 5 Side seal part 6 Seal part 7 Bottom seal part 8 Diagonal seal part 9 Convex part 10 Concave part 11 Opening zipper tape 12 Contents 13 Upper seal part 20 Flat support part 20 'Flat support part 21 Convex part 22 Concave part A Plastic bag B Plastic bag C Packaging product D Hook type chuck tape p Surface q Inner surface r Top α angle

Continuation of the front page (72) Inventor Tonaka Hayakawa 1-1-1 Ichigaya Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd.

Claims (4)

[Claims] 1. A front wall and a rear wall each having a non-thermal adhesive surface and a thermal adhesive inner surface are superimposed on each other with the thermal adhesive inner surfaces facing each other. At the lower end of the outer surface has non-thermal adhesion, the inner surface has thermal adhesion,
And, it is folded in an inverted V-shape with its inner surface outside, and further, a bottom wall having notches on both side edges is inserted, and at both side edges, a front wall and a rear wall, a front wall and a bottom wall, and Heat sealing the rear wall and the bottom wall to form a side seal portion, and forming a heat seal portion between the front wall and the rear wall through the cutout portion; At the bottom edge, the front wall and the bottom wall and the rear wall and the bottom wall are heat-sealed to form a bottom seal portion. A plastic bag for a microwave oven, wherein an oblique seal portion is formed from a top portion on both sides to a bottom seal portion. 2. The plastic bag according to claim 1, wherein an opening zipper tape is provided near an opening of the plastic bag. 3. The plastic bag according to claim 1, wherein the length of the plastic bag is greater in the horizontal direction than in the vertical direction. 4. The plastic bag according to claim 1, wherein the bottom of the plastic bag is of a boat bottom type.