JP2008110763A - Food packaging film, and packaging bag for microwave oven heating using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a food packaging film which can discharge the steam or the expanded gas of a content to the outside when a packaging bag containing a food is heated. <P>SOLUTION: This food packaging film is a laminated film of at least a resin film A and a resin film B, and the resin film A has a cutting section on the surface. Also, this packaging bag for microwave oven heating is used for the food packaging film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a food packaging film and a microwave heating packaging bag using the same.

  When a sealed package body filled with frozen food or chilled food in a packaging bag is cooked with a microwave oven, the package body may expand and rupture as the internal pressure increases in the sealed package body. In order to prevent such rupture of the package, the gas expanded by heating, such as opening the package in advance before heating or providing a hole or valve for removing steam when manufacturing a packaging bag, has been conventionally used. Means for discharging out of the package have been proposed.

  For example, in Patent Document 1, a non-adhesive portion is provided between the synthetic resin layers constituting the laminated film, a cut is made in the synthetic resin layer adjacent to the container internal space to provide a communication port, and the synthetic resin layer adjacent to the outside of the container A laminated film that forms a communication path between the inner space of the container and the outside of the container by providing the peripheral edge portion of the opening is described.

  Patent Document 2 applies a low-melting heat sealant or a release agent to a required portion of a synthetic resin stretched film, and engraves a cutting line passing through the location on the synthetic resin stretched film, Furthermore, it describes a laminated film in which a synthetic resin unstretched film having heat sealing properties is bonded to the synthetic resin stretched film.

Furthermore, Patent Document 3 describes a package having an easy-open seal part, and in a package provided with a self-standing means on the bottom and a jointed joint part joined by a heat seal with a predetermined width, As the internal pressure rises due to the above, it is described that the joint joint located in the upper part performs a relief pressure.
JP-A-8-85580 International Publication No. 01/082011 Pamphlet JP 2000-185777 A

  This invention makes it a subject to provide the film for food packaging which can discharge | release the water vapor | steam and the expanded gas of the content outside when a package is heated.

  This invention which solves the said subject is a laminated | multilayer film by which the resin film A and the resin film B were laminated | stacked at least, and the resin film A has a cutting part on the surface, It is related with the film for food packaging characterized by the above-mentioned.

  Furthermore, as one aspect, the present invention relates to a food packaging film in which the resin film A is a stretched film and the resin film B is a film having heat-fusibility.

  Moreover, this invention relates to the packaging bag for microwave oven heating formed using the said film for food packaging.

  When a package using the food packaging film of the present invention is heated, the food packaging film expands and breaks in the cut region, forming a small hole in the film surface. From the formed small hole, the water vapor or expanded gas of the contents in the package can be released to the outside.

  Hereinafter, the present invention will be described in detail.

  The film for food packaging of the present invention is a laminated film in which at least a resin film A and a resin film B are laminated, and the resin film A is a film having a cut part on the surface.

  The food packaging film of the present invention can be used as a food packaging material for heating such as microwave heating and hot water bath, and specifically, as a lid used for trays, cups, etc., or as a packaging bag used.

  The film for food packaging in the present invention has a cut portion region including a cut portion on the surface of the resin film A and a portion of the resin film B overlapping the cut portion. In addition, about the said cutting part, it mentions later by the description regarding the resin film A.

  In the laminated film constituting the food packaging film of the present invention, the cut region has a smaller film thickness and a lower breaking strength than other regions. Therefore, when the food packaging film is used, for example, in the above-described food packaging bag and heated, the stress caused by the increase in the internal pressure of the bag is concentrated in the cut region of the food packaging film, As a result, it breaks in the cut area and a small hole is formed in the food packaging film. In the present invention, the breaking strength is a stress required to break a film, and a film having a smaller breaking strength is more likely to break.

  FIG. 1 is a cross-sectional view of an exemplary food packaging film in the present invention. In FIG. 1, the food packaging film 1 includes a resin film A 1a and a resin film B 1b, and the two layers of films 1a and 1b are in close contact with each other by the adhesive layer R. Further, FIG. 1 shows a cut portion region 2 ′ having a cut portion 2 of the resin film A 1a and a portion of the resin film B 1b overlapping the cut portion 2. Here, the adhesive layer R is a conceptual adhesion site, and may be a simple adhesion site or an adhesive application site, and the bonding means is not limited.

  By the way, the laminated film constituting the food packaging film is generally formed by laminating a plurality of films having one or more functions such as airtightness, heat resistance, and light shielding properties. The laminated film in the present invention may also have a film having functions other than the resin film A and the resin film B. For example, the laminated film in the present invention may be laminated with a transparent vapor-deposited film using alumina or silica having barrier properties. An aluminum vapor deposition film, an aluminum foil film, or the like as a film having a barrier property may cause a spark when heated by a microwave oven.

  The resin film A in the present invention is a film having a cut part on the surface.

  The resin film A is preferably a film that has heat resistance and airtightness and is not deformed by stress. Examples of such a resin include polyolefins such as polyethylene and polypropylene, ethylene-vinyl alcohol copolymers, and polyethylene. Examples thereof include polyesters such as terephthalate and polyamides such as nylon. Furthermore, it is preferable that the said resin film A is a biaxially stretched film at the point which has high breaking strength. Therefore, as a preferable resin film A in the present invention, for example, biaxially stretched nylon (ON), biaxially stretched polyethylene terephthalate (PET), biaxially stretched polypropylene (OPP), biaxially stretched ethylene vinyl alcohol copolymer (EVOH) In particular, biaxially stretched polypropylene (OPP), biaxially stretched polyethylene terephthalate (PET), and biaxially stretched nylon (NY) are preferable from the viewpoint of versatility.

  On the surface of the resin film A means an arbitrary region on the film surface. Further, in the resin film A, the cutting part is a cutting part made by any means penetrating or non-penetrating in the direction perpendicular to the surface of the resin film A. The non-penetrating cutting part has, for example, a cross section of V It may be a groove shape such as a letter shape or a concave shape. Moreover, a cutting | disconnection part may continue in arbitrary linear shapes, such as a continuous line and a broken line (a dotted line is included) on the resin film A surface.

  In this invention, the resin film B is a film laminated | stacked with the resin film A, and is a film which does not have a cutting part.

  The resin film B may be a resin having such a strength that it is ruptured in a cutting region where stress is concentrated. In particular, from the viewpoint of being used as a packaging film, the resin film B has a heat sealing function as a heat sealing function. It is preferable that it is a film which has. The heat fusibility in the present invention means a characteristic suitable for thermally bonding the same or different resin films. Accordingly, examples of the resin of the resin film B having heat-fusibility include polyethylene such as linear low density polyethylene (LLDPE) and low density polyethylene (LDPE), polypropylene, and ethylene vinyl acetate copolymer (EVA). Moreover, it is preferable that the resin film B is a film which is easy to expand | extend by stress, for example, although it is preferable that it is an unstretched film, it is not limited to this.

  As for the laminated film which comprises the film for food packaging of this invention, it is more preferable that the resin film A and the resin film B which were mentioned above combined the film which has a mutually different characteristic. The above characteristics are more preferable characteristics for generating small holes in the cut region, and the difference in characteristics based on the breaking strength of the film caused by stretching, the heat resistance, etc. between the resin film A and the resin film B, or these The difference of the characteristic which arises in combination is mentioned. Specifically, the resin film A has heat resistance and high breaking strength obtained by stretching, and the resin film B has low breaking strength that can be broken by heat sealability and internal pressure. In the food packaging film of the present invention, it is particularly preferable that the resin film A is a stretched film and the resin film B is a film having heat-fusibility as a combination of the films having different characteristics. Further, the food packaging film of the present invention is preferably one that does not cause breakage or delamination due to heating at around 95 ° C. when the packaging bag using the film is boil sterilized. Examples thereof include a laminated film in which a biaxially stretched film using polyamide such as nylon and a polyethylene film as a resin film B are combined. Here, the laminated film constituting the food packaging film of the present invention may be a combination that breaks at the cutting region, and is limited to a combination of films having different characteristics of resin film A and resin film B. Not.

  The laminated film constituting the food packaging film of the present invention can be laminated and adhered to the resin film A and the resin film B by a generally used laminating method. As specific methods, dry lamination, extrusion lamination, A heat laminate etc. are mentioned. In particular, dry laminating and extrusion laminating can completely adhere the resin film A and the resin film B in the present invention without peeling. Therefore, it is preferable to use dry lamination or extrusion lamination as a method for processing the film for food packaging of the present invention. In addition, each lamination condition in dry lamination and extrusion lamination may be based on a conventional method. As an adhesive used for dry lamination, a two-component reaction type or a one-component reaction type polyurethane adhesive, an extrusion laminate is used. Examples of the adhesive used include polyethyleneimine, alkyl titanate, and polyurethane-based primer.

  FIG. 2 shows an illustrative explanatory diagram of a method for producing a food packaging film in which a resin film A and a resin film B are laminated. In FIG. 2, a resin film A 1a having a dotted line cut by a slit blade Q and a resin film B 1b coated with an adhesive (not shown in FIG. 2) and dried are laminated, and a roll S The film 1 for food packaging can be obtained by heating and pressure bonding.

  In the present invention, the method for cutting the resin film A 1a is not particularly limited. In addition to the method illustrated in FIG. 2, for example, two completely cut resin films are juxtaposed on the resin film B. Examples thereof include a method of laminating, a method of laminating using a film having no cut part, and a method of applying a cut part to one surface of the laminated film. Further, the means for applying the cutting part may be any means such as a slit blade, laser light, or roulette.

  The thickness in the cutting | disconnection part area | region of the film for food packaging in which at least the resin film A and the resin film B in this invention were laminated | stacked is the range of 20-100 micrometers, More preferably, it is 30-60 micrometers. Here, the thickness in the cut portion region includes the thickness of the uncut portion in the cut portion of the resin film A when the cut portion of the resin film A is non-penetrating. In this case, the resin film A and the resin film B break due to the concentration of stress in the cut region. The thickness of the food packaging film of the present invention other than the cut region is in the range of 40 to 120 μm, more preferably 50 to 80 μm.

  The food packaging film of the present invention described in detail above releases the water vapor and expanded gas of the contents in the packaging bag from the small holes formed in the food packaging film when the packaging bag using the film is heated. It is a film that can. Moreover, in the embodiment of the film for food packaging of the present invention, a cutting part which is a gas venting means can be easily provided in the film processing step. Furthermore, since the film for food packaging of the present invention does not use a release agent or the like as a degassing means, the adhesive strength between the films constituting the food packaging film is maintained in the periphery of the cut region without decreasing. In addition, there is no possibility of causing peeling of the laminate from the periphery of the cut region due to the distribution channel or boil sterilization, and the food and the release agent do not come into contact with each other, and thus there is an advantage in food hygiene.

  The microwave heating packaging bag of the present invention is formed using the food packaging film of the present invention.

  Moreover, the shape of the microwave oven heating packaging bag of the present invention is not particularly limited, and examples thereof include a gas palm flat bag, a three-way flat bag, a self-supporting bag, and a wing seal bag.

  Moreover, the position of the cutting part in the packaging bag for microwave oven heating of this invention is not specifically limited.

  The microwave oven heating packaging bag of the present invention can be produced by stacking and heat-sealing the resin films B in one or more of the food packaging films. The resin film B having heat-fusibility in the food packaging film of the present invention is preferably on the inner surface of the microwave heating packaging bag of the present invention, and the bonded resin films B are heat-sealed. Fuse. The above-described packaging bag shape can be formed by heat-sealing the food packaging film of the present invention in the form of a three-way seal, a joint seal, a wing seal, or the like.

  Moreover, in the packaging bag for microwave ovens of this invention, it is preferable that the resin film A is located in the outer surface of the said packaging bag from a viewpoint of suppressing the deformation | transformation of the said packaging bag by heating.

  The microwave oven packaging bag of the present invention will be described with reference to the illustrations of FIGS.

  FIG. 3 shows a three-sided flat bag 5 filled with the contents and completely sealed on all sides, and shown in a state of being expanded by microwave heating. In the cutting part 2, the food packaging film 1 is broken and a small hole 11 is formed, and water vapor and expanded gas are released.

  FIG. 4 shows an exemplary bag making process of the three-way flat bag 5 shown in FIG. The three-way flat bag 5 is produced by folding the food packaging film 1 and heat-sealing three sides of the folded portion and two open ends that engage with both ends of the folded portion. The two wall portions 4 (4a, 4b) each having the heat seal portion 3, the open end T, and the cutting portion 2 on the wall portion 4a are provided. In the wall 4a, the resin film A (film 1a in FIG. 1) is located on the outer surface of the three-way flat bag 5. By filling the contents from the unsealed open end T and heat-sealing the open end T, the three-way flat bag 5 is completely sealed.

  5A to 5C show heat seal portions 3a to 3c as exemplary shapes of the heat seal portion 3. FIG.

  FIG. 6 shows a gas palm flat bag 7 filled with the contents and sealed, and shows a state in which it is expanded by heating in a microwave oven. The food packaging film is broken at the cutting portion region 2 ′ to form a small hole 11.

  FIG. 7 shows an exemplary bag making process of the palm-span flat bag 7 shown in FIG. This gas palm flat bag 7 is manufactured by joining both the upper and lower sides or the left and right sides of the food packaging film 1 into a gas palm shape and heat-sealing, and then heat-sealing one of the remaining open ends. , A back seal portion 6a, a bottom seal portion 6b, an open end T, and a cutting portion 2. By filling the contents from the unsealed open end T and heat-sealing the open end T, the palm flat bag 7 is completely sealed.

  8 (a) and 8 (b) show an exemplary jointed flat bag 7 (7a, 7b) in which the position of the cutting part 2 is different. (A) is a palm-sized flat bag 7a in which a cut portion is provided in a direction perpendicular to the center of the bottom seal portion 6b and parallel to the longitudinal direction of the back seal portion 6a (not shown in FIG. 8). Moreover, (b) is the gas palm flat bag 7b which has the cutting part 2b from which arrangement | positioning of the cutting part 2 (2a) in the gas palm flat bag 7a differs. The cutting part 2b is arranged at a position separated by a length L from the center of the bottom seal part 6b.

  FIG. 9 shows an exemplary flat bag 10 with wings and its bag making process. As shown in FIG. 9, the food packaging film 1 is formed into a cylindrical shape by joining both upper and lower or left and right ends to a palm shape and heat-sealing, and then the heat-sealed palm-shaped joint portion is a wing seal portion 9. And Further, one of the remaining two open ends and the two bent portions engaged with the open end is used as a heat seal portion 8, and the other bent portion is cut out (cut line U) and is set as an open end T. A flat bag 10 with a wing in which a broken portion 2 of broken lines is applied to the seal portion 9 is formed. By filling the contents from the open end T and heat-sealing the open end T, the flat bag 10 with wings is completely sealed.

  10A to 10C show wing seal portions 9a to 9c as exemplary shapes of the wing seal portion 9 in the flat bag 10 with wings.

  The packaging bag for heating a microwave oven of the present invention having the above-described features can be filled and heated with frozen foods such as frozen vegetables, fried rice, Chinese dim sum, and pasty foods such as shrimp chilli and Chinese rice bowl.

  In addition, when the microwave heating packaging bag of the present invention is heated in a microwave oven, it is preferable to heat with the surface having the cut portion as an upper surface, but a small hole is formed by the cut portion region, and water vapor or expanded gas If it is a surface which can discharge | release, it will not specifically limit.

  The food packaging film of the present invention used for the microwave heating packaging bag of the present invention described above can be used as a lid for food containers such as trays and cups. In that case, the food packaging film and the above It can be used as a heating container by adhering the surfaces in contact with the food container.

  Hereinafter, specific examples of the food packaging film of the present invention and a microwave heating packaging bag using the same are shown.

Example 1 (Heating test in a packaging bag using the food packaging film of the present invention)
Regarding the microwave oven packaging bag of the present invention using four types of food packaging films obtained by combining films having the same characteristics or different characteristics, the small hole formation state of the food packaging film by heating was evaluated.

  As the food packaging film, four types of food packaging films laminated by combining the resin film A and the resin film B shown in Table 1 were used.

  All the food packaging films used were processed by using an adhesive polyurethane (trade name A969 / A5, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.) by dry laminating two films. Moreover, the cut part in the produced food packaging film was applied in advance using a slit blade before lamination as in FIG. In addition, this cutting part is the cutting part which penetrated in the solid line shape in the resin film A.

  Next, using this food packaging film, a gas palm flat bag (width 140 mm length 200 mm) was produced by the method shown in FIG. Two sets of the gas palm flat bags were prepared, each consisting of three bags. In addition, the solid line-shaped cutting part of this gas palm flat bag is in the center of the gas palm flat bag, and is parallel to the longitudinal direction of the back seal part.

  Next, 100 g of frozen vegetables and 100 g of fried rice are filled in each set of the above four types of packaging bags, put into a microwave oven (RE-S160A type high frequency output 500 w manufactured by Sharp Corporation, turntable diameter 260 mm) and cut. The surface (resin film A) having a part was heated up until the packaging bag expanded and the release of water vapor was confirmed.

  The small hole formation state by heating of the film for food packaging of the present invention was evaluated under the following conditions.

The evaluation is ◎ that formed a small hole in the cut region and maintains the original film shape of the packaging bag, ◯ that formed a small hole in the cut region and substantially maintained the film shape, Small holes were formed in the cut part region, and Δ where the film shape was somewhat deformed and x where the packaging bag was ruptured at a position different from the cut part region.

LLDPE60, LLDPE50, LLDPE40 ... Product name TUX-HC, Tosero Co., Ltd. OPP20 ... Product name FOR, Futamura Chemical Co., Ltd. PET12 ... Product name P60, Toray film processing ( As a result of the above, all the packaging bags using the film for food packaging of the present invention formed small holes in the cut region by heating. In particular, a packaging bag using a food packaging film produced by combining a stretched film (resin film A) and an unstretched film (resin film B) using different resins has a small hole formed in the cut region, and the film Stable vapor release was observed without any deformation. Even in packaging bags using food packaging films prepared by combining unstretched films using the same resin, small holes were formed in the cut region, although some deformation was seen in the food packaging film.

  From this, when the film for food packaging of the present invention was used as a packaging bag for microwave oven heating using this, a small hole was formed in the cut region of the food packaging film by microwave heating, and water vapor or expanded It was shown that gas was released out of the container. Furthermore, it was shown that the said effect can be achieved more suitably by combining the resin film A and the resin film B which have a mutually different characteristic.

Example 2 (Heating test in a three-way flat bag using the food packaging film of the present invention)
With respect to two types of microwave oven heating packaging bags, which are three-way flat bags having different heat seal shapes, the shape change when food was filled and heated was evaluated.

  The food packaging film of the present invention includes a nylon biaxially stretched film (manufactured by Unitika Ltd., Emblem ONM, thickness 15 μm) (resin film A), and an unstretched polyethylene film (manufactured by Tosero Co., Ltd.) TUX-HC (thickness 50 μm) (resin film B) was produced by laminating with a dry laminate (adhesive: Mitsui Chemicals Polyurethanes, A969 / A5). The cutting part in the produced food packaging film was applied in advance using a slit blade before lamination as in the method shown in FIG. In addition, this cutting part is the cutting part which penetrated in the continuous line shape in the stretched nylon film.

  Next, using the produced food packaging film, a three-way flat bag is prepared by the method shown in FIG. 4, and the heat seal portion 3 is shaped as the heat seal 3a or 3b shown in FIG. Three sets of 10 bags each (width 140 mm length 200 mm) were prepared. Each set of two types of three-way flat bags was filled with 200 cc of water, 200 g of commercially available Chinese rice bowl, and 200 g of shrimp chilli, microwave oven (RE-S160A type high frequency output 500 W manufactured by Sharp Corporation, turntable) (Diameter 260 mm) and heated with the surface having the cut part (resin film A) facing up.

  As the internal pressure increases with heating, the state where the small holes are formed is referred to as “small hole state”, and the state where the heating is continued for 1 minute after the vapor release is confirmed is referred to as “overheating”, and the state is observed. The small hole formation state of the film for food packaging of each packaging bag was evaluated. The results are as shown in Table 2.

  Of the three three-way flat bags filled with the contents in the “small hole state”, those having 10 packaging bags in which small holes are formed in the cutting region of the film for food packaging ◎, 9-8 An evaluation was made on the state of forming small holes in the food packaging film of the packaging bag filled with each content, with ◯ indicating that the bag is included, Δ indicating that the bag has 7 to 6 bags, and × indicating that the bag is 5 bags or less.

In 10 three-way flat bags filled with the contents of the above-mentioned “overheating”, water vapor inside the packaging bag is stably transferred to the outside of the packaging bag through a small hole formed in the cut region of the food packaging film. A packaging bag filled with each content is marked with ◎ having 10 released packaging bags, ○ having 9-8 bags, △ having 7-6 bags, and × having 5 bags or less. The small hole formation state of the food packaging film was evaluated. The above-mentioned "water vapor is stably released to the outside of the packaging bag" means that water vapor or gas is released only from the small holes without causing defects such as deformation and rupture other than the small holes of the food packaging film. Specifically, a state in which a small hole in the cut portion region is expanded by steam, a state in which the small hole in the cut portion region is ruptured from a portion other than the cut portion region, or the like is not caused.

  From the above results, in two types of three-way flat bags of the present invention having different heat seal portions, a small hole was formed in the cut region of the food packaging film, and the heating was continued. It has been shown that water vapor inside the bag is stably released from the formed small hole to the outside of the packaging bag.

  From this, the food packaging film of the present invention, in the microwave heating packaging bag using the same, by forming a small hole in the cut region regardless of the shape of the heat seal by heating, and when further heating, It was shown that water vapor in the packaging bag was stably released from the formed small hole.

Example 3 (Heating test in a gas palm flat bag using the food packaging film of the present invention)
Regarding the gassho flat bag of the present invention in which the cut portion was provided at the center of the packaging bag, the shape change when the food was filled and heated was evaluated.

  The film similar to Example 2 was used for the food packaging film.

  Furthermore, using the above-mentioned film, a gas palm flat bag was manufactured by the method shown in FIG. 6, and three sets of gas palm flat bags (width 140 mm length 200 mm) shown in FIG. Moreover, the solid line-shaped cutting part of this gas palm flat bag is in the center of the gas palm flat bag and is parallel to the longitudinal direction of the back seal part as shown in FIG.

  After filling each gassho flat bag with a tissue containing 20 cc of water, 1 Chinese bun as a frozen food, and 100 g of fried rice, a microwave oven (Sharp Corporation RE-S160A type high frequency output 500 W, turntable diameter 260 mm) ) And heated with the surface (resin film A) having the cut part facing up.

As the internal pressure rises with heating, the state where the small holes are formed is referred to as “small hole state”, and the state in which the heating is continued for 1 minute after the steam blowout is confirmed is referred to as “overheating”, and the state is observed. The small hole formation state of the food packaging film in each packaging bag was evaluated according to the same criteria as in Example 2. The results are as shown in Table 3.

  From the above results, in the gas palm flat bag when the position of the cutting part is arranged in the center of the gas palm flat bag, a small hole is formed in the cutting part region of the film for food packaging, and further, the heating was continued and formed. It was shown that water vapor inside the packaging bag was stably discharged from the small hole to the outside.

  From this, the food packaging film of the present invention, in the microwave heating packaging bag using the same, when the position of the cutting portion is arranged in the center, a small hole is formed in the cutting portion region of the food packaging film, It was shown that when the heating was continued, water vapor in the packaging bag was stably released from the formed small hole.

Example 4 (Heating test in a flat bag with wings using the food packaging film of the present invention)
With respect to two types of packaging bags for heating a microwave oven, which are flat bags with wings having different heat seal shapes at the wing seal portion, the shape change when food was filled and heated was evaluated.

  The film similar to Example 2 was used for the food packaging film.

  Next, a flat bag with a wing is produced by the method shown in FIG. 9 using the above-mentioned food packaging film, and two types of flat bags with a wing seal portion 9a or 9b shown in FIG. 200 mm), 3 sets of 10 bags each.

  Furthermore, each set of flat bags with wings was filled with 300 cc of water, 300 g of commercially available Chinese rice bowl, and 300 g of shrimp chilli, and microwave oven (Sharp Corporation RE-S160A type high frequency output 500 W, turn (Table diameter 260 mm) and heated with the surface (resin film A) having the cut part facing up.

As the internal pressure increases with heating, the state where the small holes are formed is referred to as “small hole state”, and the state in which the heating is continued for 1 minute after the steam blowing is confirmed is referred to as “overheating”, and the state is observed. The small hole formation state of the food packaging film in each packaging bag was evaluated according to the same criteria as in Example 2. The results are as shown in Table 4.

  From the above results, in the two types of flat bags with wings of the present invention having different wing seal portions, a small hole was formed in the cut portion region of the film for food packaging, and the heating was continued. It was shown that the water vapor inside the packaging bag was stably discharged to the outside.

  Therefore, the food packaging film of the present invention is a microwaveable packaging bag using the same, and the wrapping bag with wings cuts the food packaging film by heating regardless of the shape of the wing seal portion. It was shown that when a small hole was formed in the partial area and further heating was continued, water vapor in the packaging bag was stably released from the formed small hole.

Example 5 (Heating test for boil sterilization in a three-way flat bag and a flat bag with wings using the food packaging film of the present invention)
Regarding the three-way flat bag 3a of Example 2 and the flat bag 9a with wing of Example 4, the shape change when these were filled with food and heated under boil sterilization conditions was evaluated.

  The three-way flat bag uses the food packaging film of Example 2 and the same bag making method as in Example 2. The winged flat bag uses the food packaging film of Example 4 and forms the same bag as in Example 4. Three sets of 10 bags each were prepared by the method.

  Further, each set was filled with 200 cc of water, 200 g of commercially available Chinese rice bowl, and 200 g of shrimp chilli, and poured into a hot water bath preheated to 95 ° C. so that the packaging bag could be completely used. The mixture was heated for 30 minutes while maintaining 95 ° C. The heating was performed in an open state without closing the lid on the hot tub. The shape change of the film for food packaging of the packaging bag after heating was evaluated as follows.

In each set of three-way flat bags and gassho-flat bags filled with the above contents, those having 10 packaging bags that maintain the shape of the food packaging film before heating are ◎, having 9-8 bags , A having 7-6 bags, Δ, 5 or less. The results are as shown in Table 5. The “maintaining shape” state is a state in which the film does not break around the cut part region or outside the cut part region, the film does not peel around the cut part region, and the film is not stretched.

  From the above results, it was confirmed that the food packaging film maintained the shape before heating in the three-way flat bag and the flat bag with wings of the present invention by heating under boil sterilization conditions.

  Therefore, the food packaging film of the present invention does not form a small hole in the cut portion region by boiling sterilization performed after filling and sealing of frozen food or pasty food in a microwave heating packaging bag using the film. It was shown that the contents did not leak and the film shape was maintained immediately after packaging.

1 is a cross-sectional view of an exemplary food packaging film of the present invention. It is exemplary illustration of the manufacturing method of the film for food packaging of this invention. It is a perspective view of the package body which filled the contents, such as foodstuffs, in the packaging bag for microwave oven heating of the three-way flat bag as an example of embodiment of this invention. It is explanatory drawing which shows the example bag making process of the packaging bag for microwave oven heating of the three-way flat bag in FIG. It is a front view which shows the exemplary heat seal shape of the packaging bag for microwave oven heating of the three-way flat bag as an example of embodiment of this invention. It is a perspective view of the package which filled the contents, such as a foodstuff, in the microwave oven heating packaging bag of the gas palm flat bag as an example of the embodiment of the present invention. It is explanatory drawing which shows the example bag making process of the packaging bag for microwave oven heating of the gas palm flat bag in FIG. It is a perspective view which shows the example fracture | rupture part position of the packaging bag for microwave oven heating of the gas palm flat bag as an example of embodiment of this invention. It is explanatory drawing which shows the example bag making process of the packaging bag for microwave oven heating of the flat bag with a wing as an example of embodiment of this invention. It is a front view which shows the exemplary heat seal shape in the wing seal part of the packaging bag for microwave oven heating of the flat bag with a wing as an example of embodiment of this invention.

Explanation of symbols

1 Food Packaging Film 1a Resin Film A
1b Resin film B
2 Cutting part 2 'Cutting part region 3, 3a, 3b, 3c Heat seal part 4, 4a, 4b Wall part 5 Three-way flat bag 6a Back seal part 6b Bottom seal part
7, 7a, 7b Joint palm flat bag 8 Heat seal part 9, 9a, 9b, 9c Wing seal part 10 Flat bag with wing 11 Small hole Q Slit blade R Adhesive layer S Roll T Open end U Cut line

Claims (3)

  A film for food packaging, which is a laminated film in which at least a resin film A and a resin film B are laminated, and the resin film A has a cut portion on the surface.   The food packaging film according to claim 1, wherein the resin film A is a stretched film, and the resin film B is a film having heat-fusibility.   A microwave heating packaging bag formed using the food packaging film according to claim 1.

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