JP2008297015A - Plastic pouch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic pouch with a flat pouch type which can be efficiently produced at a low cost, and can hold a position of an automatic opening mechanism which is automatically opened by increasing the inner pressure of the pouch at a high position without using an auxiliary tool when the pouch is placed flat in the electric range and is cooked by heating. <P>SOLUTION: At least one of the front film and the back film constituting the plastic pouch is folded back over the whole length in the width direction, and the peripheral edge part is heat-sealed to form at least one position of the folding back part communicating with the pouch body, and the automatic opening mechanism which is automatically opened when the pouch is heated by the microwave oven is formed near the end part of the pouch close to the folded back part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flat pouch type plastic pouch formed by heat-sealing the peripheral edge of a plastic film constituting both front and back surfaces of the pouch. The plastic pouch of the present invention is filled with contents such as a retort food made of a liquid, a solid or a mixture thereof, and is suitably used as a microwave cooking pouch.

  When a packaging bag filled and sealed with retort food, frozen food, etc. is heated in a microwave oven, the pressure inside the bag rises due to water vapor generated from the contents during heating, and the packaging bag bursts and the contents scatter. At the same time, the inside of the microwave oven may be soiled, or the human body may be burned.

For this reason, before such a packaging bag is cooked in a microwave oven, the packaging bag is partially opened in advance, or water vapor generated in the packaging bag is generated by opening a hole in the packaging bag body. A method is taken to prevent the packaging bag from being broken.
However, such a method is time-consuming for general consumers, and since steam generated by microwave heating is immediately discharged out of the packaging bag, the steaming effect by steam is reduced and the taste is reduced. There is a drawback of falling.

In order to solve such problems, various types of plastic pouches have been proposed that are provided with a mechanism that automatically opens when the internal pressure of the pouch rises in order to automatically release the increase of the internal pressure in the pouch during microwave heating.
As a plastic pouch provided with such an automatic opening mechanism, a standing pouch that heats the pouch by being self-supported in a microwave oven (for example, see Patent Documents 1 and 2), an automatic opening mechanism is provided in a flat bag or a branch part. Various types are known, such as a flat-type pouch that lays a packaging bag in a microwave oven and heats it like a branched pouch (see, for example, Patent Documents 3 to 5).

Among these pouches, the most excellent in terms of productivity and cost is a flat pouch type pouch, but this type of pouch is automatically opened when cooking in a microwave oven or when the internal pressure increases. Later, since the position of the automatic opening mechanism cannot be stably held at a high position, there is a drawback in that the contents of the pouch are ejected from the automatic opening or leaked out.
For this reason, in order to hold the automatic opening mechanism of the flat pouch-type microwave heating cooking pouch at a high position, it has been proposed to use an auxiliary tool such as an individual packaging box (see Patent Document 6). There is a problem that it is troublesome because it uses an auxiliary tool separate from the pouch, and it leads to cost increase.

JP 2002-249176 A JP 2003-192042 A Japanese Patent Laid-Open No. 2002-80072 JP 2001-106270 A Japanese Patent Publication No. 8-25583 JP 2003-170930 A

  The present invention eliminates the above-mentioned problems of the prior art, can be produced efficiently at low cost, and increases the internal pressure of the pouch without using an auxiliary tool when cooking horizontally and cooking in a microwave oven. An object of the present invention is to provide a flat pouch-type plastic pouch that can stably hold the automatic opening mechanism that automatically opens at a high position.

  As a result of intensive studies, the inventors have turned back at least one film constituting the plastic pouch over the entire length in the width direction of the pouch, and heat-sealed the peripheral portion to form a folded portion communicating with the pouch body. The present invention has been completed by discovering that the problem is solved.

That is, in the present invention, the following configurations 1 to 12 are adopted.
1. At least one of the front film and the back film constituting the plastic pouch is folded over the entire length in the width direction of the pouch, and at least one folded portion communicating with the pouch body is formed by heat sealing the peripheral portion. Plastic pouch.
2. 2. The plastic pouch according to 1, wherein the folded portion is formed on both the front film and the back film constituting the pouch.
3. 3. The plastic pouch according to 1 or 2, wherein the folded portion is formed near one end of the pouch.
4). 3. The plastic pouch according to 1 or 2, wherein the folded portion is formed near both ends of the pouch.
5. 5. The plastic pouch according to any one of 1 to 4, wherein a folded portion is formed by folding a film constituting the plastic pouch into a Z shape.
6). 5. The plastic pouch according to any one of claims 1 to 4, wherein a folded portion is formed by folding the film constituting the plastic pouch into a Z shape and then folding it back into an inverted Z shape.
7). In the peripheral seal portion of the folded portion, an opening is provided in the film existing in the inner layer rather than the film disposed in the outermost layer of the front surface film and the back surface film constituting the peripheral seal portion, and both the front and back surfaces are provided through the open hole portion. The plastic pouch according to any one of 1 to 6, wherein the film disposed in the outermost layer is heat-sealed.
8). The plastic pouch according to any one of claims 1 to 7, wherein an automatic opening mechanism that automatically opens when the pouch is heated by a microwave oven is formed at or near the end of the pouch close to the folded portion.
9. 9. The plastic pouch according to 8, wherein the automatic opening mechanism is formed in contact with the peripheral seal portion at the end of the pouch.
10. 10. The plastic pouch according to 9, wherein an automatic opening mechanism is formed by providing a projecting portion whose tip is directed inward of the pouch at a peripheral seal portion at the end of the pouch.
11. 9. The plastic pouch according to 8, wherein the automatic opening mechanism is formed separately from the peripheral seal portion at the end of the pouch.
12 The plastic pouch according to any one of 8 to 11, wherein the automatic opening mechanism is a steam vent seal part having a weakened part.

  The plastic pouch of the present invention does not require an additional member or process unlike a standing pouch or a branched pouch, and can be efficiently produced at a low cost close to that of a flat pouch. In addition, when cooking horizontally in a microwave oven, the position of the automatic opening mechanism that automatically opens due to the increase in the internal pressure of the pouch without using an auxiliary tool is stably held at a high position, It is possible to prevent the contents from being blown out or leaked out.

  As the plastic film constituting the plastic pouch of the present invention, a plastic material having heat sealing properties which is usually used for manufacturing a packaging bag is used. Examples of such a plastic material include a single-layer film made of a thermoplastic resin having heat-sealability, a sheet, a multilayer film in which a thermoplastic resin having heat-sealability is laminated with another thermoplastic resin, and the like. Can be mentioned.

  Examples of such a heat-sealable plastic material include known low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, polypropylene, propylene-ethylene copolymer, and ethylene-vinyl acetate copolymer. Olefin resins such as olefin resins graft-modified with ethylenically unsaturated carboxylic acids or their anhydrides, polyamides or copolyamide resins having a relatively low melting point or low softening point, polyesters or copolyester resins, polycarbonate resins, etc. Is done.

Moreover, as another plastic material laminated | stacked with the plastic material which has heat-sealing property, the film which consists of a thermoplastic resin with or without heat-sealing property, various barrier films, etc. can be used.
Examples of such thermoplastic resins include crystalline polypropylene, crystalline propylene-ethylene copolymer, crystalline polybutene-1, crystalline poly-4-methylpentene-1, low-, medium-, or high-density polyethylene, Polyolefins such as ethylene-vinyl acetate copolymer (EVA), EVA saponified product, ethylene-ethyl acrylate copolymer (EEA), ion-crosslinked olefin copolymer (ionomer); polystyrene, styrene-butadiene copolymer, etc. Aromatic vinyl copolymers; halogenated vinyl polymers such as polyvinyl chloride and vinylidene chloride resins; polyacrylic resins; nitrile polymers such as acrylonitrile-styrene copolymers, acrylonitrile-styrene-butadiene copolymers; polyethylene Terephthalate, polytetramethylene terephthalate It can be exemplified thermoplastic resins such as polyacetal such as polyoxymethylene and the like; over polyesters such as preparative; various polycarbonates; fluorine-based resin. These thermoplastic resins can be used alone or in combination of two or more, and various additives may be used in combination.

  Various barrier films include silica-deposited polyester film, alumina-deposited polyester film, silica-deposited nylon film, alumina-deposited nylon film, alumina-deposited polypropylene film, carbon film-deposited polyester film, carbon film-deposited nylon film, and alumina and silica. Binary vapor-deposited film co-deposited on base film such as polyester film and nylon film, nylon 6 / metaxylylenediamine nylon 6 co-extruded film, polypropylene / ethylene-vinyl alcohol copolymer co-extruded film, and polyvinyl alcohol coated polypropylene Film, Polyvinyl Alcohol Coated Polyester Film, Polyvinyl Alcohol Coated Nylon Film, Polyacrylic Acid Tree Coated polyester film, polyacrylic acid resin coated nylon film, polyacrylic acid resin coated polypropylene film, polyglycolic acid resin coated polyester film, polyglycolic acid resin coated nylon film, organic resin coating such as polyglycolic acid resin coated polypropylene film Examples thereof include a film and a hybrid coating material made of an organic resin material and an inorganic material coated on a base film such as a polyester film, a nylon film, or a polypropylene film. These barrier films can be used alone or in combination of two or more.

Furthermore, as another plastic material laminated with a plastic material having heat sealability, a film made of an oxygen-absorbing resin or a laminated film of an oxygen-absorbing resin and another thermoplastic resin can also be used.
As the oxygen-absorbing resin, (1) the resin itself uses a resin having oxygen-absorbing property, or (2) a tree composition in which an oxygen-absorbing agent is blended in a thermoplastic resin having or not having oxygen-absorbing property. Can be used. There is no restriction | limiting in particular as a thermoplastic resin which comprises an oxygen absorptive resin composition (2), Both the thermoplastic resin which has oxygen barrier property, and the thermoplastic resin which does not have oxygen barrier property can be used. As the thermoplastic resin constituting the resin composition (2), when the resin itself has an oxygen-absorbing property or an oxygen-barrier property, oxygen in the container is combined with the oxygen absorbing effect by the oxygen absorbent. This is preferable because it can effectively prevent the intrusion of.

  Examples of the resin itself having oxygen absorptivity include those utilizing an oxidation reaction of the resin. Oxidizing organic materials such as polybutadiene, polyisoprene, polypropylene, ethylene carbon monoxide copolymer, polyamides such as 6-nylon, 12-nylon, metaxylylenediamine (MX) nylon, cobalt as an oxidation catalyst Organic acid salts containing transition metals such as rhodium and copper, and those added with photosensitizers such as benzophenone, acetophenone and chloroketones can be used. When these oxygen-absorbing materials are used, further effects can be exhibited by irradiating with high energy rays such as ultraviolet rays and electron beams.

As the oxygen absorber to be blended in the thermoplastic resin, all the oxygen absorbers conventionally used for this kind of application can be used. However, in general, those which are reducible and substantially insoluble in water are preferable. Examples include metal powders having reducibility, such as reducible iron, reductive zinc, reducible tin powder; metal lower oxides such as FeO, Fe ₃ O ₄ ; reducible metal compounds such as iron carbide, silicon iron , Iron carbonyl, ferrous hydroxide, etc., or a combination of two or more thereof. As a particularly preferred oxygen absorbent, reducing iron, for example, iron oxide obtained in the steel production process is reduced with coke, and the resulting sponge iron is pulverized and then subjected to finish reduction in hydrogen gas or decomposed ammonia gas. And iron that is electrolytically deposited from an aqueous iron chloride solution obtained in the pickling step, and reduced iron that has been subjected to finish reduction after pulverization can be used.
These oxygen absorbers can be used as required in alkali metal, alkaline earth metal hydroxides, carbonates, sulfites, thiosulfates, tertiary phosphates, secondary phosphates, organic acid salts, halogens. It can also be used in combination with an oxidation accelerator composed of an electrolyte such as a chemical compound, and further an auxiliary agent such as activated carbon, activated alumina, activated clay. Particularly preferred oxidation promoters include sodium chloride, calcium chloride, or combinations thereof.
When reducing iron and an oxidation accelerator are used in combination, the blending ratio of both is 99 to 80 parts by weight of reducing iron and 1 to 20 parts by weight of an oxidation accelerator, with the total amount being 100 parts by weight. It is preferable to use 98 to 90 parts by weight of reducing iron and 2 to 10 parts by weight of an oxidation accelerator.

Other oxygen absorbers include polymer compounds having a polyhydric phenol in the skeleton, such as polyhydric phenol-containing phenol / aldehyde resins. Furthermore, ascorbic acid, erythorbic acid, tocopherols and salts thereof, which are water-soluble substances, can be suitably used. Of these oxygen-absorbing substances, reducing iron and ascorbic acid compounds are particularly preferable.
Moreover, you may mix | blend the resin in which said resin itself has oxygen absorptivity in a thermoplastic resin as an oxygen absorber.

  These oxygen absorbents generally have an average particle size of preferably 50 μm or less, particularly 30 μm or less. When transparent or translucent is required, the average particle size is 10 μm or less, particularly 5 μm or less. It preferably has a diameter. The oxygen absorbent is preferably blended in the above resin in a proportion of 1 to 70% by weight, particularly 5 to 30% by weight.

  In this invention, the packaging bag for microwave ovens is comprised by heat-sealing the unstretched film comprised by the said plastic material, or the uniaxially or biaxially stretched by the conventional method. When the film is a laminated film of a thermoplastic resin having heat sealing properties and a thermoplastic resin having no heat sealing properties, heat sealing is performed so that the thermoplastic resin layers having heat sealing properties become inner surfaces. .

Next, the structure of the flat pouch type plastic pouch of the present invention will be described with reference to the drawings. However, the following specific examples do not limit the present invention.
1-3 is a figure which shows an example of the plastic pouch of this invention, FIG. 1 is a schematic diagram explaining the manufacturing process of a pouch, FIG. 2 is the top view which looked at the pouch from the back side.
FIG. 3 is a schematic view showing a state in which this pouch is heated in a microwave oven, (A) shows a state where the pouch is not opened and is being cooked, and (B) shows a state where the pouch is partially opened. Indicates that cooking has been completed.

The pouch 1 is manufactured by superimposing a film 11 constituting the front surface of the pouch and a film 12 constituting the back surface of the pouch and heat-sealing the peripheral edge. At that time, the film 12 constituting the back surface of the pouch is folded back in a Z shape over the entire length in the width direction of the pouch, and the peripheral edge portion is heat-sealed except for one short side end portion which becomes the filling port 4 of the contents. The folded portion 2 communicating with the pouch body is formed. Further, a peripheral seal portion is projected in a U shape toward the inside of the pouch at the short side end opposite to the filling port 4, and an opening (through hole) portion 7 is provided in the projection 6. A steam vent seal portion having a weakened portion is formed, and the automatic opening mechanism 5 is automatically opened when the pouch is heated in a microwave oven.
As a method for forming the weakened portion, it goes without saying that other known methods such as providing a semi-through hole, a slit or an unsealed portion instead of the opening (through hole) can be adopted.

  After filling the pouch 1 with the contents such as the retort food, when the pouch sealed by sealing the filling port 4 with heat is placed in a microwave oven and cooked, the pouch is heated by steam generated from the contents. The internal pressure rises and the pouch expands. At this time, water vapor also enters the folded portion 2 provided on the back surface 12 of the pouch, and the end portion of the pouch provided with the automatic opening mechanism 5 rises from the folded portion 2 (see FIG. 3A).

As the internal pressure of the pouch 1 increases, stress concentrates on the tip of the protruding portion 6 of the automatic opening mechanism 5, the seal portion gradually peels toward the outside of the pouch, and when the peeling reaches the opening 7, the pouch Partially opening, water vapor or the like is discharged to the outside through the opening 7, and the internal pressure of the pouch is lowered. Also at this time, the folded-back portion 2 provided on the back surface 12 of the pouch functions like a stand, and the opened automatic opening mechanism 5 is stably held at a high position (see FIG. 3B).
Thus, in this pouch 1, the automatic opening mechanism 5 formed in the pouch is held at a high position even during cooking by the microwave oven and after the end of cooking, and the contents can be prevented from being ejected or leaked out.

4 and 5 are views showing another example of the plastic pouch according to the present invention. FIG. 4 is a schematic view for explaining the manufacturing process of the pouch. FIG. 5 is a plan view of the pouch as viewed from the back side. .
In this pouch 21, the film 12 constituting the back surface of the pouch is folded back in a Z shape over the entire length in the width direction of the pouch, and then folded back in an inverted Z shape to form the folded portion 2. The automatic opening mechanism 5 is formed by projecting the peripheral seal portion in a U-shape toward the inside of the pouch and providing an opening 7 in the protruding portion 6 that communicates with the outside of the pouch. Other configurations of the pouch 21 are the same as those of the pouch 1 shown in FIGS.

  In this pouch 21, since the film is folded on both sides of the folded portion 2, the volume of the folded portion 2 that is spread by steam intrusion when the pouch 21 is cooked in a microwave oven increases. As a result, the end of the pouch starting from 2 can be easily raised, and the automatic opening mechanism 5 can be stably held at a higher position.

6-8 is a figure which shows the other example of the plastic pouch of this invention, FIG. 6 is a schematic diagram explaining the manufacturing process of a pouch, FIG. 7 is the top view which looked at the pouch from the front side, and FIG. FIG. 5 is an enlarged schematic view illustrating a process of forming a folded portion of a pouch.
In this pouch 31, by folding both the film 11 constituting the front surface of the pouch and the film 12 constituting the back surface into the reverse Z shape and the Z shape at the same position, the folded portions 32 and 32 are formed on both sides of the pouch. Form.

When the folded portions 32 and 32 are formed, as shown in FIG. 8, the folded portions 32 and 32 are positioned in an inner layer than the film disposed in the outermost layer of the front surface film 11 and the back surface film 12 constituting the peripheral seal portions 3 and 3. The film is provided with opening portions 33 (in this example, a total of four locations), and the films 11 and 12 disposed on the outermost layers on both the front and back surfaces are heat-sealed through the opening portions 33.
By configuring the heat seal in the folded portion 32 in this manner, the heat seal strength of the peripheral seal portion 3 in the folded portions 32 and 32 is increased, and the rising edge of the pouch end when the pouch 31 is cooked in a microwave oven. It can be certain.
In addition, said structure which provides an opening part in the film located in the peripheral seal part inner layer of a folding | turning part is applicable also to the pouch of FIGS. 1-5 which forms a folding | turning part only in the back surface film of a pouch.

Further, in this pouch 31, the automatic opening mechanism 35 is weakened by heat-sealing the film on both the front and back surfaces at a position separated from the peripheral seal portion 3, and providing an opening (through hole) 37 in the heat seal portion 36. A steam release seal portion 36 having a portion 37 is formed.
As a method of forming the weakened portion 37, it is needless to say that other known methods such as providing a semi-through hole, a slit or an unsealed portion instead of the opening (through hole) can be adopted.

9 to 11 are views showing other examples of the plastic pouch of the present invention. FIG. 9 is a schematic view for explaining the manufacturing process of the pouch, FIG. 10 is a plan view of the pouch as seen from the back side, and FIG. FIG. 3 is a schematic diagram showing a state where a pouch is heated in a microwave oven.
In this pouch 42, the first folded portion 42 is formed by folding the film 12 constituting the back surface of the pouch into a Z shape over the entire length in the width direction of the pouch at a position from one end portion of the pouch, and from the other end of the pouch. The second folded portion 42 is formed by folding the film 12 in an inverted Z-shape at the position.
In addition, at both ends of the pouch 42, the automatic opening mechanisms 45 and 45 are formed by providing steam release seal portions 46 each having a weakened portion 47 by opening at positions separated from the peripheral seal portion 3.

When the pouch 41 is placed flat in a microwave oven and heated, the internal pressure of the pouch 41 increases due to water vapor generated from the contents, and the pouch 41 expands. At that time, water vapor also enters the folded portions 42, 42, the both sides of the pouch 41 rise from the folded portions 42, 42, and the automatic opening mechanisms 45, 45 are held at high positions (FIG. 11). reference). Even after the automatic opening mechanisms 45 and 45 are opened and the internal pressure of the pouch 41 is reduced and cooking is completed, the pouch 41 maintains its shape in a contracted state. Therefore, this pouch 41 can be used like a tray.

In each of the above examples, the example in which the automatic opening mechanism is provided in the pouch as the plastic pouch of the present invention has been described. However, the plastic pouch having the folded portion of the present invention is configured without providing such an automatic opening mechanism. Is also possible.
The automatic opening mechanism employed in the present invention is not particularly limited. For example, the peripheral seal portion of the pouch projects in a U shape or a V shape toward the inside of the pouch, and an unsealed portion that communicates with the outside of the pouch is provided in the projecting portion. The unsealed portion can be punched to constitute an automatic opening mechanism. In addition to the steam release seal portion, any means known as an automatic opening mechanism can be employed, such as configuring an automatic opening mechanism using a member separate from the pouch.
Needless to say, the dimensions and shape of the plastic pouch and the material of the film constituting the pouch can be selected as appropriate.

It is a schematic diagram explaining the process of manufacturing one example of the plastic pouch of this invention. It is the top view which looked at the plastic pouch obtained by the process of FIG. 1 from the back side. It is a schematic diagram showing the state which heated the pouch of FIG. 2 within the microwave oven. It is a schematic diagram explaining the process of manufacturing the other example of the plastic pouch of this invention. It is the top view which looked at the plastic pouch obtained by the process of FIG. 4 from the back side. It is a schematic diagram explaining the process of manufacturing the other example of the plastic pouch of this invention. It is the top view which looked at the plastic pouch obtained by the process of FIG. 6 from the front side. It is a schematic diagram explaining the process of forming the folding | turning part of the pouch of FIG. It is a schematic diagram explaining the process of manufacturing the other example of the plastic pouch of this invention. It is the top view which looked at the plastic pouch obtained by the process of FIG. 9 from the back side. It is a schematic diagram showing the state which heated the pouch of FIG. 10 within the microwave oven.

Explanation of symbols

1, 21, 31, 41 Plastic pouches 2, 32, 42 Folded part 3 Peripheral seal part 4 Filling port 5, 35, 45 Automatic opening mechanism 6 Protruding part 7, 33, 37, 47 Opening 11 Front film 12 Back film 36 46 Vapor vent seal

Claims (9)

  At least one of the front and back films constituting the plastic pouch is folded over the entire length in the width direction of the pouch, and at least one folded portion communicating with the pouch body is formed by heat-sealing the peripheral portion, which is close to the folded portion. A plastic pouch characterized by forming an automatic opening mechanism in the vicinity of an end of the pouch, which automatically opens when the pouch is heated by a microwave oven.   The plastic pouch according to claim 1, wherein the folded portion is formed on both the front film and the back film constituting the pouch.   The plastic pouch according to claim 1 or 2, wherein the folded portion is formed near one end of the pouch.   The plastic pouch according to any one of claims 1 to 3, wherein a folded portion is formed by folding a film constituting the plastic pouch into a Z-shape.   The plastic pouch according to any one of claims 1 to 3, wherein a folded portion is formed by folding the film constituting the plastic pouch into a Z shape and then folding it back into an inverted Z shape.   The plastic pouch according to any one of claims 1 to 5, wherein the automatic opening mechanism is formed by connecting to a peripheral seal portion at an end portion of the pouch.   7. The plastic pouch according to claim 6, wherein an automatic opening mechanism is formed by providing a projecting portion whose tip is directed inward of the pouch at a peripheral seal portion of the pouch end.   The plastic pouch according to any one of claims 1 to 5, wherein the automatic opening mechanism is formed separately from the peripheral seal portion at the end of the pouch. The plastic pouch according to any one of claims 1 to 8, wherein the automatic opening mechanism is a steam vent seal portion having a weakened portion.

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