WO2020184176A1 - Packaging film for heating in microwave oven, packaging body for heating in microwave oven, and method for producing heat-insulated packaging body - Google Patents

Abstract

The present invention provides a packaging film for heating in a microwave oven, the packaging film having a flat shape prior to heating in a microwave oven, deforming to a bumpy shape after heating in a microwave oven, and manifesting heat-insulation properties.　This packaging film for heating in a microwave oven is formed such that a first film and a second film are laminated, and has a sealant layer on a rearmost surface, wherein: the first film has heat-shrinking properties, and undergoes heat shrinking in at least a first direction; and the second film has substantially no heat-shrinking properties, and undergoes heat shrinking in only a second direction orthogonal to the first direction, or in a direction that is oblique to the first direction. Between the layers of the first film and the second film, there is an intermittent adhesion region having adhesion parts at which the layers of the first film and the second film adhere to each other and non-adhesion parts at which the layers of the first film and the second film do not adhere to each other. In the intermittent adhesion region, the adhesion parts and the non-adhesion parts are alternatingly arranged in the first direction.

Description

Manufacturing method for microwave oven heating packaging film, microwave oven heating packaging, and heat insulating packaging

The present invention relates to a packaging film or the like for packaging an object to be heated in a microwave oven.

Conventionally, a microwave oven-heating package in which an object to be heated in a microwave oven (hereinafter, an object to be heated in a microwave oven is referred to as an "object to be heated") is wrapped in a packaging film has been distributed. Generally, the object to be heated is mostly food, but it may be other than food, for example, non-food such as hand towels. The form of the package for heating the microwave oven is that the object to be heated itself is wrapped in a packaging film, or the object to be heated is housed in a container or bag and the container or bag is wrapped in the packaging film. There is a form of packaging. With respect to such a package for heating in a microwave oven, the object to be heated may be taken out from the packaging film and heated in a microwave oven, but for convenience, the package itself is often heated in a microwave oven. .. After heating the packaging itself in a microwave oven, the packaging film also becomes hot as the temperature of the object to be heated rises.

Japanese Unexamined Patent Publication No. 2001-335309

Patent Document 1 (Japanese Unexamined Patent Publication No. 2001-335309) discloses a microwave oven heating package packaged with a packaging film having an uneven surface (embossed). In such a package, the surface of the packaging film is an uneven surface, so that the contact area of the handle is small and the package has a heat insulating effect. However, in the package of Patent Document 1, since the surface of the packaging film is an uneven surface even before being heated in the microwave oven, the appearance of the package may be spoiled. In addition, fine dust may adhere to the concave portions on the uneven surface during the distribution process of the package.

An object of the present invention is to provide a packaging film for heating a microwave oven, which has a smooth surface before being heated in a microwave oven and changes into an uneven shape to exhibit heat insulating properties after being heated in a microwave oven. To do.

The packaging film for heating a microwave oven of the present disclosure is a packaging film in which a first film and a second film are laminated and has a sealant layer on the innermost back surface, and the first film is heat-shrinked at least in the first direction. The film has heat shrinkage, and the second film is a film having substantially no heat shrinkage, a film that heat shrinks only in the second direction which is orthogonal to the first direction, or a first direction. It is a film that heat-shrinks in the direction of inclination, and between the layers of the first film and the second film, there is an adhesive portion to which the layers of the first film and the second film are bonded, and the layers of the first film and the second film. There is an intermittent bonded region having a non-bonded portion and a non-bonded portion, and in the intermittent bonded region, the bonded portion and the non-bonded portion are alternately arranged in the first direction.

In the packaging film for heating a microwave oven of the present disclosure, it is preferable that the first film is located between the second film and the sealant layer.

In the packaging film for heating a microwave oven of the present disclosure, it is preferable that the non-adhesive portion has a portion that extends continuously in a direction non-parallel to the first direction of the first film.

In the packaging for microwave oven heating of the present disclosure, the object to be heated in the microwave oven is wrapped by any of the above packaging films.

In the microwave oven heating package of the present disclosure, the object to be heated is housed in a container having a flange portion, and the intermittent adhesive region of the packaging film corresponds to the upper surface of the flange portion of the container. Is preferably wrapped by the packaging film.

In the method for producing a heat-insulating package of the present disclosure, any of the above-mentioned packaging for heating in a microwave oven is heated using a microwave oven to change the intermittent adhesive region of the packaging film into an uneven shape.

According to the microwave oven heating packaging film and the microwave oven heating packaging body of the present invention, the surface thereof is smooth before being heated in the microwave oven. Therefore, the appearance is good, and fine dust does not unnecessarily accumulate on the surface. On the other hand, after heating in a microwave oven, the intermittent adhesive region changes into an uneven shape to form an uneven surface. Therefore, the microwave oven heating packaging film and the microwave oven heating packaging body after being heated in the microwave oven can exhibit heat insulating properties.

FIG. 1 is a plan view of a long strip-shaped packaging film viewed from the front side, in which a part is omitted. FIG. 2 is a plan view of one sheet-shaped wrapping film cut out from a long strip-shaped wrapping film as viewed from the surface side. FIG. 3 is a schematic cross-sectional view taken along the line III-III of FIG. FIG. 4 is a schematic cross-sectional view taken along the line IV-IV of FIG. FIG. 5 is a plan view showing a first arrangement example of the bonded portion and the non-bonded portion in the intermittent bonding region. FIG. 6 is a plan view showing a second arrangement example of the bonded portion and the non-bonded portion in the intermittent bonding region. FIG. 7 is a plan view showing a third arrangement example of the bonded portion and the non-bonded portion in the intermittent bonding region. FIG. 8 is a plan view showing a fourth arrangement example of the bonded portion and the non-bonded portion in the intermittent bonding region. FIG. 9 is a schematic side view showing a process of packaging an object to be heated using a packaging film. FIG. 10 is a perspective view of the package of the first example. FIG. 11 is a perspective view of the package of the second example. FIG. 12 is a top view of the package of the second example. FIG. 13 is a front view of the package of the second example. FIG. 14 is a schematic cross-sectional view taken along the line XIV-XIV of FIG. FIG. 15 is a schematic cross-sectional view of the package after being heated in a microwave oven. FIG. 16 is a schematic cross-sectional view of the packaging film before being heated in the microwave oven, cut along the first direction. FIG. 17 is a schematic cross-sectional view of the packaging film after being heated in a microwave oven, cut along the first direction. FIG. 18 is a schematic cross-sectional view of the packaging film before being heated in the microwave oven, cut along the second direction. FIG. 19 is a schematic cross-sectional view of the packaging film after being heated in a microwave oven, cut along the second direction. FIG. 20 is a plan view showing a fifth arrangement example of the bonded portion and the non-bonded portion in the intermittent bonding region.

Hereinafter, this disclosure will be described with reference to the drawings. In the present specification, the "front surface" refers to the outer surface (the surface opposite to the packaged object) when the packaged object is wrapped with the packaging film, and the "back surface" is the packaging film. Refers to the inner surface (the surface on the packaged side) when the packaged object is wrapped. Further, the "first direction" and the "second direction" are orthogonal to each other in the plane of the film. In the present specification, the numerical range represented by "lower limit value XXX to upper limit value YYY" means a lower limit value XXX or more and an upper limit value YYY or less. When a plurality of the numerical range are described separately, it is possible to select an arbitrary lower limit value and an arbitrary upper limit value and set "arbitrary lower limit value to arbitrary upper limit value".

<Packaging film for heating in microwave oven>
The microwave oven heating packaging film (hereinafter, also simply referred to as “wrapping film”) according to the present disclosure will be described in detail with reference to FIGS. 1 to 8.

FIG. 1 shows a long strip-shaped wrapping film 8, and FIG. 2 shows a size for wrapping one object to be packaged (the object to be heated itself or a container or bag containing the object to be heated). The packaging film 9 of the above is shown. In the mechanical production process, the packaging film 8 is usually supplied in the form of a long body as shown in FIG. 1, and is conceptually cut into a size capable of packaging one object to be packaged. The two-dot chain line in FIG. 1 indicates the planned cutting line of the long strip-shaped packaging film 8, and the single-wafer-shaped packaging film cut by the planned cutting line is the packaging film 9 shown in FIG. In other words, the long strip-shaped wrapping film 8 is a series of a plurality of wrapping films 9 having a size capable of wrapping one object to be packaged.

Here, the long strip shape means a substantially rectangular shape in a plan view in which the length in the longitudinal direction is sufficiently longer than that in the lateral direction. Examples of the long strip shape include a configuration in which the length in the longitudinal direction is 5 m or more (preferably 10 m or more) and the length in the lateral direction is 100 mm to 1000 mm. The lateral direction is a direction orthogonal to the longitudinal direction.

As shown in FIGS. 3 and 4, the long strip-shaped wrapping film 8 (including the single-wafer-shaped wrapping film 9) is a laminate of the first film 1 and the second film 2. Further, the outermost surface has a sealant layer (not shown). The first film 1 is a film that heat-shrinks at least in the first direction. The second film is a film having substantially no heat shrinkage. Between the layers of the first film 1 and the second film 2, the bonding portion 3 in which the layers of the first film 1 and the second film 2 are bonded and the layers of the first film 1 and the second film 2 are not bonded. There is an intermittent adhesive region 6 having a non-adhesive portion 4. In the intermittent adhesive region 6, the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the first direction. The white arrow in FIG. 3 indicates a portion corresponding to the planned cutting line. The first film 1 and the second film 2 are long strips having the same shape and the same size in a plan view.

In the present disclosure, the first film 1 and the second film 2 are laminated in the thickness direction, but the first film 1 may be laminated on the surface side of the second film 2, or the first film 1 may be laminated. It may be laminated on the back surface side of the second film 2. Preferably, in the packaging film 8, the first film 1 is laminated on the back surface side of the second film 2, as shown in the illustrated example. In FIGS. 3 and 4, the surface facing the upper side of each drawing is the front surface, and the surface facing the lower side of each drawing is the back surface.

[First film]
The first film 1 is a film that heat-shrinks at least in the first direction. Here, the heat-shrinkable film refers to a film that does not shrink at room temperature (for example, 23 ° C.) but has a property of shrinking in a predetermined direction when heated to a heat-shrinkage temperature (for example, 80 ° C. to 100 ° C.). .. The film that heat-shrinks at least in the first direction is a film that has heat-shrinkability in at least the first direction. The first film 1 is preferably a film that heat-shrinks in the first direction and the second direction.

Here, the first direction means one direction in the plane of the film, and the second direction is a direction orthogonal to the first direction in the plane. The first direction is, for example, the lateral direction of the long strip-shaped wrapping film 8, and the second direction is the longitudinal direction of the long strip-shaped wrapping film 8. The first direction may be the longitudinal direction of the long strip-shaped packaging film 8.

The heat shrinkage rate of the first film 1 in the first direction is not particularly limited, but is preferably 20% or more, more preferably 30% or more, and further preferably 40% or more. When the first film 1 is a film that heat-shrinks in the second direction, the heat-shrinkage rate in the second direction is not particularly limited, but is preferably 20% or more, more preferably 30% or more, and further. It is preferably 40% or more. The upper limit of the heat shrinkage rate in the first direction and the second direction is theoretically less than 100%.

However, the heat shrinkage of the film is the length of the film (original length) before heating (stored for 24 hours under standard conditions (23 ° C, 1 atm, 50% RH atmosphere)) and 10 in warm water at 90 ° C. The length of the film after being immersed for seconds and taken out (the length after immersion) is measured under standard conditions, and is obtained by substituting into the following formula.
Heat shrinkage rate (%) = [{(original length in the first direction (or second direction))-(length after immersion in the first direction (or second direction))} / (first direction (or second direction) Or the original length)] x 100 in the second direction).

As the first film 1, various films can be used provided that they have the above-mentioned thermal properties. Examples of the material of the first film 1 include a synthetic resin film, a non-woven fabric film, and a foamed resin film. Further, the first film 1 may be a laminated film containing at least one selected from the above materials. The laminated film may be a laminate of a film having substantially no heat shrinkage and a film having heat shrinkage, provided that the laminate as a whole has heat shrinkage. A laminate made of a film in which all of them have heat shrinkage is preferable.

Preferably, a synthetic resin film or a laminated film having a synthetic resin layer is used as the first film 1, and more preferably, a single-layer synthetic resin film or a multi-layer synthetic resin film is used. The single-layer synthetic resin film is a film composed of a single synthetic resin layer, and the multi-layer synthetic resin film is a laminated film in which two or more synthetic resin layers are laminated.

The material of the synthetic resin film (synthetic resin layer) is not particularly limited, and polyester resins such as polyethylene terephthalate and polylactic acid; olefin resins such as polyethylene, polypropylene and cyclic olefins; polystyrene, styrene-butadiene copolymers and the like. Polystyrene resin; Polypropylene resin; One kind selected from thermoplastic resins such as vinyl chloride resin, or a mixture of two or more kinds can be mentioned. The material of the non-woven fabric film or the foamed resin film is not particularly limited, and examples thereof include those using a conventionally known synthetic resin. The non-woven fabric film and the foamed resin film can be expected to have a heat insulating effect by themselves.

The heat-shrinkable synthetic resin film is obtained by a known film-forming method. For example, a synthetic resin and a resin composition containing various additives as necessary are mixed with a mixer or the like, melted using an extruder, extruded from a T die, stretched and heat-set. Obtainable. The stretching treatment may be either a tenter method or a tube method. The stretching treatment is usually performed at a temperature of about 70 to 110 ° C. independently in the longitudinal direction (for example, the MD direction during film formation) and / or the lateral direction (TD direction during film formation), respectively. It is carried out by stretching 8.0 times (preferably about 3.0 to 7.0 times). When stretched in both the longitudinal direction and the lateral direction, the biaxially stretched film can be heat-shrinked in both the first direction and the second direction.

The thickness of the first film 1 is not particularly limited, and is, for example, 10 μm to 300 μmm. In particular, when a synthetic resin film is used as the first film 1, the thickness thereof is, for example, 10 μm to 100 μm. Further, when the packaging film 8 is processed into the form of a pillow packaging bag, the first film 1 of the packaging film preferably has a thickness of 10 μm to 30 μm.

Further, the first film 1 may be transparent (colorless transparent or colored transparent) or non-transparent. When the first film 1 is arranged on the surface side, the first film 1 is preferably transparent, and more preferably colorless and transparent. This is to improve the visibility of the design print layer 5. Generally, synthetic resin films are colorless and transparent (or colored transparent), and non-woven fabric films, papers and foamed resin films are opaque.

[Second film]
The second film 2 is a film having substantially no heat shrinkage. A film having substantially no heat shrinkage means that it does not shrink at room temperature and hardly shrinks even when heated to the above heat shrinkage temperature. For example, in terms of heat shrinkage, the second film 2 having substantially no heat shrinkage has heat shrinkage rates of 0 to 5% independently in the first direction and the second direction, which is preferable. It is 0 to 3%. The meaning of the heat shrinkage rate is as described above.

Examples of the second film 2 include a synthetic resin film having substantially no heat shrinkage, paper, a non-woven fabric film having substantially no heat shrinkage, and a foamed resin having substantially no heat shrinkage. Examples include a film and a laminated film containing at least one selected from these. The laminated film is a laminate of a film having substantially no heat shrinkage and a film having heat shrinkage, provided that the laminate as a whole does not have substantially heat shrinkage. However, a laminate in which all of them do not have substantially heat shrinkage is preferable. The materials of the synthetic resin film, the non-woven fabric film, and the foamed resin film that can be used as the second film 2 can be appropriately selected and used from those exemplified in the first film 1. Examples of paper include plain paper and Japanese paper.

The thickness of the second film 2 is not particularly limited, and is, for example, 8 μm to 300 μmm. In particular, when a synthetic resin film is used as the second film 2, the thickness thereof is, for example, 8 μm to 120 μm, preferably 12 μm to 100 μm. When the packaging film 8 is processed into the form of a pillow packaging bag, the second film 2 of the packaging film 8 preferably has a thickness of 8 μm to 60 μm, and more preferably 8 μm to 30 μm. By using the second film 2 having such a thickness, when the first film 1 is thermally shrunk, the second film 2 tends to change into a convex shape satisfactorily.

Further, the second film 2 may be transparent (colorless transparent or colored transparent) or non-transparent. In FIGS. 3 and 4, since the second film 2 is arranged on the surface side, the second film 2 is preferably transparent, and more preferably colorless and transparent in the present disclosure.

[Sealant layer and heat resistant layer]
The packaging film 8 has a sealant layer on the innermost back surface. In FIGS. 3 and 4, the sealant layer is located on the back surface side of the first film 1. The sealant layer is a layer that constitutes the innermost back layer of the packaging film 8 and is meltable by heating to a predetermined temperature and can be heat-welded. Therefore, the packaging film 8 can be processed into a packaging bag by heat welding.

For example, when the first film 1 is arranged on the back surface side of the second film 2 as shown in the illustrated example, a film having a sealant layer on the innermost back surface is used for the first film 1. When the first film 1 is a single-layer synthetic resin film, a synthetic resin film (synthetic resin layer) having a sealant property is used. When the first film 1 has a plurality of layers, a film in which at least the backmost layer is composed of a synthetic resin layer having a sealant property is used.

Further, the packaging film 8 preferably has a heat-resistant layer on the outermost surface. The heat-resistant layer constitutes the outermost surface layer of the packaging film 8 and is a layer that does not melt at the temperature at which the sealant layer melts. For example, when the first film 1 is arranged on the back surface side of the second film 2 as shown in the illustrated example, it is preferable to use a film having a heat resistant layer on the outermost surface as the second film 2. .. When the second film 2 is a single-layer synthetic resin film, it is preferable to use a heat-resistant synthetic resin film (synthetic resin layer). When the second film 2 has a plurality of layers, it is preferable to use a film in which at least the outermost surface layer is composed of a heat-resistant synthetic resin layer.

When the second film 2 is arranged on the back surface side of the first film 1, a film having a sealant layer on the innermost back surface is used for the second film 2, and 1 for the first film is the most. It is preferable to use a film having a heat-resistant layer on the surface. When the second film 2 is a single-layer synthetic resin film, a synthetic resin film (synthetic resin layer) having a sealant property is used. When the second film 2 has a plurality of layers, a film in which at least the backmost layer is composed of a synthetic resin layer having a sealant property is used. When the first film 1 is a single-layer synthetic resin film, a heat-resistant synthetic resin film (synthetic resin layer) is used. When the first film 1 has a plurality of layers, a film in which at least the outermost surface layer is composed of a heat-resistant synthetic resin layer is used.

Examples of the synthetic resin film having a sealant property (the same applies to the synthetic resin layer having a sealant property) include conventionally known sealant films such as low-density polyethylene film, ethylene-propylene copolymer film, and ethylene-olefin copolymer film. And so on. Examples of the heat-resistant synthetic resin film (the same applies to the heat-resistant synthetic resin layer) include conventionally known heat-resistant films such as polyester-based resin films such as polyethylene terephthalate and polyamide-based resin films such as nylon. ..

[Other layers]
Even if the first film 1 and / or the second film 2 is provided with a design print layer 5 representing a desired display such as a product name, a pattern, or a mechanical reading symbol such as a bar code, if necessary. Good. The design print layer 5 can be formed by printing a desired colored ink on a film.

The design print layer 5 is usually provided so as to be visible from the surface side of the packaging film 8. For example, when both the first film 1 and the second film 2 are transparent, the design print layer 5 is provided on the front surface and / or the back surface of the first film 1 and / and the second film 2. In the packaging film 8 in which the first film 1 is laminated on the back surface side of the second film 2, the design print layer 5 is preferably provided on the front surface and / or the back surface of the second film 2. In the illustrated example, the design print layer 5 is provided only on the back surface of the second film 2. The design print layer 5 may be provided entirely or partially. The design print layer 5 is provided in an appropriate area according to the display content.

[Intermittent adhesive area]
With reference to FIGS. 3 and 4, the first film 1 and the second film 2 are adhered so as not to separate from each other. In the normal lamination, the two films are completely adhered to each other, but in the packaging film 8 of the present invention, the layers of the first film 1 and the second film 2 are intermittently adhered to each other. Has an adhesive area. The intermittent adhesive region has an adhesive portion 3 in which the layers of the first film 1 and the second film 2 are adhered, and a non-adhesive portion 4 in which the layers of the first film 1 and the second film 2 are not even adhered. ing.

In the present specification, "adhesion" refers to a state in which two films are bonded by physical or / or chemical force and are bonded with a strength that cannot be easily peeled off by human power. "Non-adhesive" refers to a state that does not have the above-mentioned bond. "Non-adhesive" includes the state where the two films are in contact with each other and slightly separated from each other, but differs from "adhesive" in that the two films can be separated with substantially no load.

The intermittent adhesive region may be formed over the entire packaging film 8, or may be formed in a part of the packaging film 8. It should be noted that some areas do not mean one area. When the intermittent adhesive region is provided in a part of the packaging film 8, the first film 1 and the second film 2 are completely adhered (solid adhesive) in the region other than the intermittent adhesive region. ing. Hereinafter, in comparison with the intermittent adhesive region, the region where the first film 1 and the second film 2 are completely adhered (solid adhesive) is referred to as a “total adhesive region”.

As will be described later, when the packaging film 8 is heated in a microwave oven, the intermittent adhesive region of the packaging film 8 changes into an uneven shape. Therefore, the portion that is not desired to be changed to the uneven shape is not the intermittent adhesive region but the entire adhesive region. Is preferable. Further, as will be described later, when the packaging film 8 is bonded by a heat seal when the packaging body is manufactured, in order to perform the heat seal well, the portion serving as the bonding allowance is an intermittent adhesive region. It is preferable that the entire surface is an adhesive region.

From this point of view, in the illustrated example, the intermittent adhesive region is provided in a part of the packaging film 8. In FIGS. 1 and 2, for convenience, innumerable dots are added to the intermittent adhesive region in order to clearly represent the region. Further, in FIGS. 3 and 4, the intermittent adhesive region is indicated by reference numeral Z, and the entire surface adhesive region is indicated by reference numeral W. Examples of the portion that is not desired to be changed to the unevenness include an area in which the mechanical reading symbol is represented by the design printing layer 5, a region in which the component display of the object to be heated is represented, a region in which the handling instruction is represented, and the like. Can be mentioned.

In the illustrated example, the area where the mechanical reading symbol is represented by the design printing layer 5, the area where the component display of the object to be heated is represented by the design printing layer 5, the pair of side ends 81, 81, and the planned cutting. The vicinity portion 82 of the line is a full-scale adhesive region, and the other portion is an intermittent adhesive region. In FIGS. 1 and 2, the region in which the mechanical reading symbol is represented is indicated by reference numeral X, and the region in which the component indication is represented is indicated by reference numeral Y. The pair of side end portions 81, 81 of the packaging film 8 and the portion 82 near the planned cutting line serve as a joining allowance when the packaging body is manufactured.

The intermittent adhesive region has an adhesive portion 3 in which the layers of the first film 1 and the second film 2 are adhered, and a non-adhesive portion 4 in which the layers of the first film 1 and the second film 2 are not adhered. .. The entire surface adhesive region has only an adhesive portion 3 in which the layers of the first film 1 and the second film 2 are adhered.

5 to 8 are plan views showing an example of arrangement of the bonded portion and the non-bonded portion in the intermittent bonding region. The alternate long and short dash line square enclosure in FIGS. 5 to 8 means that a part of the intermittent adhesive region is taken out, the shaded portion in the square enclosure indicates the adhesive portion 3, and the white background portion is the non-adhesive portion. 4 is shown.

5 and 6 are examples in which a plurality of adhesive portions 3 are arranged in independent dots. In FIGS. 5 and 6, a plurality of independent point-shaped adhesive portions 3 are arranged at intervals in both the first direction and the second direction. The plan view shape of the point-shaped adhesive portion 3 is not particularly limited, and is, for example, a substantially circular shape as shown in FIG. 5, a substantially cross shape as shown in FIG. 6, and a substantially elliptical shape, which is not shown. It may be a substantially polygonal shape such as a triangular shape or a substantially quadrangular shape, or a substantially star shape.

The plurality of point-shaped adhesive portions 3 may have the same shape and the same size, may have the same shape and the same size, may have the same shape and different sizes, or may have different shapes and sizes. Preferably, as shown in the illustrated example, the plan-view shapes of the plurality of point-shaped adhesive portions 3 are the same shape and the same size. The plurality of point-shaped adhesive portions 3 may be arranged at regular intervals in the first direction, or may be arranged at different intervals in places. Similarly, the plurality of point-shaped adhesive portions 3 may be arranged at regular intervals in the second direction, or may be arranged at different intervals in places. Preferably, as shown in the illustrated example, the plurality of adhesive portions 3 are arranged at equal intervals in both the first direction and the second direction.

When viewed along the first direction, which is the heat shrinkage direction of the first film 1, with reference to FIGS. 5 and 6, the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the first direction. , There is a portion where the non-adhesive portion 4 continuously extends in the first direction. Hereinafter, in a predetermined direction (first direction or second direction), a portion in which the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged is referred to as an "alternate arrangement band", and a predetermined direction (first direction or second direction). ), The portion where the non-adhesive portion 4 is continuously extended may be referred to as a “non-adhesive continuous band”. The alternating band and the non-adhesive continuous band are alternately arranged in the second direction.

On the other hand, when viewed along the second direction, the portion where the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the second direction (alternate arrangement band) and the non-adhesive portion 4 are continuous in the second direction. There is an extending portion (non-adhesive continuous band; a non-adhesive portion 4 continuously extending in a direction non-parallel to the first direction (direction orthogonal to the first direction)). The alternating band and the non-adhesive continuous band are also alternately arranged in the first direction. That is, the adhesive portion 3 is provided so that the alternating arrangement band and the non-adhesive continuous band alternately exist in both the first direction and the second direction.

7 and 8 are examples in which a plurality of adhesive portions 3 are arranged in a strip shape. In FIG. 7, an intermittent bonding region in which a plurality of strip-shaped bonding portions 3 extending in a direction orthogonal to the first direction (direction parallel to the second direction) are arranged is shown. In FIG. 8, a plurality of band-shaped adhesive portions 3 extending at an acute angle with respect to the first direction are arranged as intermittent adhesive regions at intervals in the second direction.

In FIG. 7, a plurality of strip-shaped adhesive portions 3 extending in the second direction are arranged at intervals in the first direction. When viewed along the first direction, which is the heat shrinkage direction of the first film 1, with reference to FIG. 7, a portion (alternate arrangement band) in which the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the first direction. ), But does not have a non-adhesive continuous band. On the other hand, when viewed along the second direction, a portion in which the non-adhesive portion 4 extends continuously in the second direction (non-adhesive continuous band. A direction non-parallel to the first direction (perpendicular to the first direction). There are a non-adhesive portion 4) that extends continuously in the direction) and a portion (hereinafter, referred to as an adhesive continuous band) in which the adhesive portion 3 continuously extends in the second direction. The non-adhesive continuous band and the adhesive continuous band are alternately arranged in the first direction.

In FIG. 8, when viewed along the first direction, which is the heat shrinkage direction of the first film 1, there is a portion (alternate arrangement band) in which the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the first direction. However, it does not have a non-adhesive continuous band and an adhesive continuous band. On the other hand, when viewed along the second direction, there is a portion (alternate arrangement band) in which the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the second direction, but there is a non-adhesive continuous band and an adhesive continuous band. Do not. In the example of FIG. 8, when viewed along a direction non-parallel to the first direction (acute angle direction with the first direction), there are a non-adhesive continuous band and an adhesive continuous band. That is, the non-adhesive portion 4 has a portion continuously extending in a direction non-parallel to the first direction of the first film 1. The inclination angle of the band-shaped adhesive portion 3 with respect to the first direction is not particularly limited as long as it is an acute angle, but it is preferably about 30 degrees to 70 degrees, more preferably about 40 degrees to 50 degrees. In the illustrated example, it is 45 degrees. The band-shaped adhesive portion 3 is not limited to a straight line, but may be a wavy line, a zigzag line, or the like (not shown).

In the preferred arrangement examples shown in FIGS. 5 to 8, the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the first direction, which is the heat shrinkage direction of the first film 1, and the portion. The non-adhesive portion 4 has a portion that is continuously extended in a direction non-parallel to the first direction of the first film 1. The intermittent adhesive region of such an arrangement is likely to be deformed in a convex shape at a portion corresponding to the non-adhesive portion 4 when the first film 1 is thermally shrunk by the heat generated by heating in a microwave oven. It is preferable because it becomes.

Further, in the preferred arrangement examples shown in FIGS. 5, 6 and 8, in each case, the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the second direction of the first film 1 and the non-adhesive portion 3. The adhesive portion 4 has a portion that is continuously extended in a direction non-parallel to the second direction of the first film 1. As described above, when the first film 1 is heat-shrinked not only in the first direction but also in the second direction, the second film 2 is not adhered to the intermittent adhesive region of the arrangement example in the second direction as well. It becomes easy to be deformed in a convex shape at the portion corresponding to the portion 4.

The width of the adhesive portion 3 in the first direction and the width of the adhesive portion 3 in the second direction are not particularly limited and can be set as appropriate. The width of the adhesive portion 3 in the first direction and the width of the adhesive portion 3 in the second direction are independently, for example, 1 mm to 7 mm, preferably 2 mm to 5 mm. The width of the non-adhesive portion 4 in the first direction and the width of the non-adhesive portion 4 in the second direction are not particularly limited and can be set as appropriate. The width of the non-adhesive portion 4 in the first direction and the width of the non-adhesive portion 4 in the second direction are independently, for example, 1 mm to 7 mm, preferably 2 mm to 5 mm. When the width of the adhesive portion 3 in the first direction and the width of the adhesive portion 3 in the second direction are not constant as shown in FIGS. 5 and 6, for example, those widths mean the maximum values. Further, the width of the non-adhesive portion 4 in the first direction is the length between two adhesive portions 3 adjacent to each other in the first direction, and the width of the non-adhesive portion 4 in the second direction is adjacent in the second direction. It is the length between the two adhesive portions 3 to be formed. When the width of the non-adhesive portion 4 in the first direction and the width of the non-adhesive portion 4 in the second direction are not constant as shown in FIGS. 5 and 6, for example, those widths mean the maximum value.

The adhesive portion 3 is composed of means for adhering the first film 1 and the second film 2, such as an adhesive and a solvent. For example, by applying an adhesive to the front surface of the first film 1 (or / and the back surface of the second film 2) and superimposing the front surface of the first film 1 and the back surface of the second film 2, the first film 1 And the second film 2 are adhered to each other via an adhesive (adhesive portion 3). When the first film 1 and the second film 2 are made of a material that can be bonded to the solvent, a solvent is applied to the front surface of the first film 1 (or / and the back surface of the second film 2), and the first film thereof. By superimposing the front surface of 1 and the back surface of the second film 2, the first film 1 and the second film 2 are melted and adhered by a solvent (in this case, the first film 1 and the second film 2 are directly bonded to each other. Adhere).

The packaging film 8 is formed by applying an adhesive or a solvent to the front surface (or / and the back surface of the second film 2) of the first film 1 and adhering the first film 1 and the second film 2 as described above. can get. The method of applying the adhesive or solvent is not particularly limited, and examples thereof include coating using a printing method such as a gravure printing method. According to the printing method, an adhesive (or solvent) having a desired shape can be easily applied to a desired region of the film, so that an intermittent adhesive region and a full-scale adhesive region can be formed in the desired region.

<Use of microwave oven heating packaging film and microwave oven heating packaging>
The long strip-shaped packaging film 8 is flexible and is usually stored and transported in a rolled state. Since the front surface and the back surface of the packaging film 8 of the present disclosure are smooth before being heated in a microwave oven, they are unlikely to collapse even if they are rolled into a core material. Further, since the wrapping film 8 is smooth as described above, the winding diameter is smaller than that when the conventional wrapping film formed in an uneven shape is wound in a roll shape, and the wrapping film 8 is wound longer by one core material. It becomes possible. The flexible packaging film 8 is typically processed into a packaging bag for wrapping an object to be heated, and is used. For example, the packaging film 8 is processed into a so-called pillow packaging bag, pouch packaging bag, or the like. Preferably, the packaging film 8 of the present invention is a pillow packaging film processed into a pillow packaging bag.

Examples of objects to be heated include foods such as cooked foods and uncooked foods, and non-foods such as hand towels and body towels. The object to be packaged may be the object to be heated as it is, or the object to be heated may be contained in a container or a bag. When the packaging film 8 is processed into a pouch packaging bag, the object to be packaged is often the object to be heated itself. When the object to be heated is food, it is preferable that the object to be heated is packaged in the packaging film 8 while being contained in the container. As the container, various conventionally known containers can be used, and examples thereof include a shallow dish-shaped or deep dish-shaped container and a cup-shaped container. Further, the container may have a flange portion.

FIG. 9 is a schematic side view showing a process of packaging an object to be heated using a packaging / BR> T-ilm. Specifically, FIG. 9 is a side view showing an outline of a packaging machine 6 (so-called horizontal pillow packaging machine 6) for mounting a long strip-shaped packaging film 8 on an object to be packaged 7. The wrapping machine 6 includes a transport device 61 for transporting the object to be packaged 7 and the wrapping film 8, a molding device (not shown) for molding the wrapping film 8 into a tubular shape, a heat sealing device 62, and a heat fusing cutter 63. Have.

As described above, since the wrapping film 8 has a sealant layer on the innermost back surface, the back surfaces of the wrapping film 8 can be easily joined by overlapping the back surfaces and heating from the front surface side. For example, a film that can be heat-shrinkable in the first and second directions and has a sealant property (for example, a polyolefin-based film such as a low-density polyethylene film or a polypropylene film) and substantially heat-shrinkable. The second film 2 (for example, a polyester-based film such as a polyethylene terephthalate film, a polybutylene terephthalate film, or a polylactic acid film), which is a film having no heat resistance, has an intermittent adhesive region and is laminated and bonded. The packaging film 8 that has been used can be used.

In FIG. 9, a long strip-shaped wrapping film 8 wound on a roll is pulled out to a line, and the wrapping film 8 is formed by a molding apparatus so that the lateral direction (first direction) of the wrapping film 8 is the circumferential direction. Form in a tubular shape. When forming a tubular shape, the pair of side end portions 81, 81 are overlapped so that the back surface side of the packaging film 8 is on the inside. The object to be packaged 7 is inserted into the cylinder of the wrapping film 8 formed into a tubular shape at regular intervals by the transport device 61, and the pair of overlapped side ends 81 and 81 are heat-sealed. The pair of side ends 81, 81 are joined by a thermal seal by passing between the devices 62.

A long wrapping film 8 formed into a tubular shape by joining a pair of side ends 81 and 81 with a heat seal is formed into a heat fusing cutter 63 while being shaped so as to wrap one object to be packaged 7. Flute and heat seal along the short side. The portion to be heat-fused by the heat fusing cutter 63 is the planned cutting line in FIG. 1, and the portion to be heat-sealed at the same time as the heat fusing is the portion 82 near the planned cutting line. As a result, a package 10 as a microwave oven heating package is obtained in which the periphery of one object 7 is wrapped with the packaging film 8.

With reference to FIGS. 10 to 14, the package 10 according to the microwave heating package of the present disclosure is a package 7 and a packaging bag 89 in which a packaging film 8 is formed in a bag shape. It is composed of a packaging bag 89 that wraps the bag. 10 to 14 show the package 10 before being heated in the microwave oven. The package 10 is distributed in this form and is microwave-heated during use, as described below.

In the package 10 of the illustrated example, the object to be heated 72 is housed in the container 71 having the flange portion 712 as the object to be packaged 7. The container 71 has a concave container body 711 for accommodating the object to be heated 72, and a flange portion 712 provided at the upper end of the container body 711 and extended in the outer diameter direction. The flange portion 712 is provided on the entire periphery of the upper end portion of the container body 711, and forms an annular shape when viewed from above. However, the flange portion 712 is not limited to the case where the flange portion 712 is provided on the entire circumference of the container body 711 in a top view, and may extend from a part of the container body 711 (not shown).

In the packaging bag 89 shown in FIG. 10, the packaging film 8 wraps the periphery of the object to be packaged 7, and the pair of side end portions 81, 81 of the packaging film 8 are overlapped with each other and heat-sealed to form the joint portion 89a. The tubular film is formed by forming the tubular film, and the two tubular mouth ends of the tubular film are flattened and heat-sealed to form the joint portions 89b and 89b, thereby forming a sealed bag shape. Such a packaging bag 89 is in the form of a so-called back-paste type pillow packaging bag. Further, the packaging bag 89 is in the form of a so-called gusset type pillow packaging bag in which a joint portion is formed by folding a part inward when flattening the end portions of the two cylinder mouths.

In the packaging bag 89 shown in FIGS. 11 to 14, the two cylinder mouth ends of the packaging body 10 shown in FIG. 10 are flattened and heat-sealed, and the joint portions 89b and 89b are further brought into close contact with the outer surface of the packaging bag 89. It is bent like this. In order to prevent the bent joints 89b and 89b from returning to their original positions, the bent joints 89b and 89b are attached to the outer surface of the packaging bag 89 via an adhesive such as a heat-sensitive adhesive 89c (for example, a hot melt adhesive). It is glued. The packaging bag 89 is not limited to the gusset type, and may be a type without a gusset (not shown).

With reference to FIG. 14, the packaging bag 89 (wrapping film 8) wraps the container 71 with a gap between the back surface thereof and the container 71. If necessary, the packaging bag 89 may be provided with conventionally known steam venting means. As will be described later, the steam venting means is a mechanism for letting steam generated from the object to be heated 72 escape to the outside of the packaging bag 89 when the packaging body 10 is heated in a microwave oven. As the steam venting means, conventionally known means can be used. For example, the following configuration can be mentioned.
(A) A part of the joint portion of the packaging film 8 is set as a weak joint portion (the weak joint portion is a portion where the joint is released and the steam escapes to the outside when the inside of the packaging bag 89 is pressurized by steam);
(B) A hole is opened in a part of the packaging bag 89, and the hole is closed with a label that peels off when steam is generated (for example, JP-A-2018-052513, JP-A-2015-193419, etc.);
(C) A steaming label that heat-melts a part of the packaging film 8 to form vents when heated in a microwave oven is attached (Japanese Patent Laid-Open No. 2008-201483, etc.).

When the packaging body 10 is formed by using the packaging film 8 in which the intermittent adhesive region is partially provided, the intermittent adhesive region is set to correspond to the upper surface 712a of the flange portion 712 of the container 71 and is heated. It is preferable that the container 71 (object to be packaged 7) containing the object 72 is wrapped with the packaging film 8. Further, the container 71 containing the object to be heated 72 is wrapped with the packaging film 8 so that the intermittent adhesive region corresponds to the upper surface 712a of the flange portion 712 and the side surface side of the flange portion 712. preferable.

In FIG. 12, a thin diagonal line is provided in the range corresponding to the upper surface 712a of the flange portion 712 of the container 71, and in FIG. 13, a thin diagonal line is provided in the range corresponding to the side surface side of the flange portion 712 of the container 71. There is. As a preferable packaging form, there is a form in which the intermittent adhesive region is arranged in the entire range corresponding to the upper surface 712a of the flange portion 712. Further, as another preferable form, there is a form in which the intermittent bonding region is arranged in a part of the range corresponding to the upper surface 712a of the flange portion 712. That is, it is preferable that the intermittent bonding region is arranged at least a part of the range corresponding to the upper surface 712a of the flange portion 712.

A part of the range corresponding to the upper surface 712a of the flange portion 712 is, for example, 20% or more, preferably 30% or more, when the area of the entire upper surface of the flange portion 712 is 100%. Similarly, in the above preferred packaging form, the intermittent adhesive region may be arranged in the entire range corresponding to the side surface side of the flange portion 712, and the intermittent bonding region may be arranged in a part of the range corresponding to the side surface side of the flange portion 712. A target adhesive region may be arranged. That is, a packaging form in which the intermittent bonding region is arranged at least a part of the range corresponding to the side surface side of the flange portion 712 is more preferable. However, the intermittent bonding region is arranged so as to correspond to the upper surface of the flange portion 712, and is continuously arranged so as to correspond to the side surface side of the flange portion 712. When the packaging body 10 is formed by using the packaging film 8 provided with the intermittent adhesive region over the entire surface, the intermittent adhesive region is inevitably the upper surface of the flange portion 712 of the container 71. It is arranged in the entire range corresponding to the 712a and the side surface side.

<Manufacturing method of heat insulating packaging>
The above-mentioned package 10 is used by heating it using a microwave oven. As the microwave oven, a general-purpose microwave oven used for heating food or the like, for example, a household microwave oven or a commercial microwave oven may be used. The package 10 provided with the steam venting means is heated in a microwave oven as it is. When the steam venting means is not provided, it is desirable to form a steam venting hole in a part of the packaging bag 89 and then heat the package 10 in a microwave oven.

When heated in a microwave oven, the object to be heated 72, which can generate steam, is heated to generate steam, and heat is transferred to the packaging bag 89 (packaging film 8) to cause the packaging bag 89 to shrink. As shown in FIG. 15, the heat-shrinked packaging bag 89 comes into close contact with the outer surface of the container 71. That is, the packaging body 10 of FIG. 15 is a packaging body 10 to which heat insulating properties are imparted by being heated in a microwave oven, and is a heat insulating packaging body. However, the packaging bag 89 does not come into close contact with the lower surface of the flange portion 712, and a gap remains between the lower surface of the flange portion 712 and the outer peripheral surface of the container body 711 and the packaging bag 89.

<Effect>
In the packaging film 8 of the present disclosure, a first film 1 which has heat shrinkage and at least heat shrinks in the first direction and a second film 2 which does not substantially have heat shrinkage are laminated. The first film 1 and the second film 2 are laminated and bonded by having an intermittent bonding region. According to such a packaging film 8, the first film 1 is heat-shrinked, while the second film 2 is not heat-shrinked in the intermittent adhesive region. Therefore, the second film 2 changes from smooth to uneven.

This change will be specifically described with reference to FIGS. 16 to 19. FIG. 16 is a schematic cross-sectional view of the packaging film before being heated in the microwave oven, cut along the first direction. FIG. 17 is a schematic cross-sectional view of the packaging film after being heated in a microwave oven, cut along the first direction. FIG. 18 is a schematic cross-sectional view of the packaging film before being heated in the microwave oven, cut along the second direction. FIG. 19 is a schematic cross-sectional view of the packaging film after being heated in a microwave oven, cut along the second direction. In FIGS. 16 to 19, the design print layer is omitted.

In the packaging film 8 (packaging bag 89) shown in FIGS. 16 to 19, the first film 1 has heat shrinkage in the first direction. As shown in FIG. 16, the packaging film 8 has alternating bands in the first direction in the intermittent bonding region. Therefore, when the first film 1 heat-shrinks in the first direction during microwave heating, as shown in FIG. 17, the portion of the second film 2 corresponding to the non-adhesive portion 4 heat-shrinks the first film 1. While the portion of the second film 2 corresponding to the adhesive portion 3 follows the heat shrinkage of the first film 1, it changes in a convex shape so as to project toward the surface side without following the heat shrinkage. No longer. Along with these changes, the second film 2 changes in an uneven shape along the first direction. Further, when heating in a microwave oven, heat is generated from the object to be heated 72 (because heat is generated from the inside of the packaging bag 89), so that the packaging film 8 in which the heat-shrinkable first film 1 is laminated on the back surface side is , There is an advantage that it easily changes to the uneven shape.

Further, the first film 1 also has heat shrinkage in the second direction, and as shown in FIG. 18, the first film 1 has an alternating arrangement band in the second direction in the intermittent adhesive region (this is a case where the first film 1 has heat shrinkage in the second direction. (In the case of the arrangement example of the adhesive portion 3 and the non-adhesive portion 4 in FIGS. 5, 6, and 8), when the first film 1 heat-shrinks in the first direction during heating in a microwave oven, similarly, as shown in FIG. In addition, the second film 2 projects toward the surface side along the second direction and changes into an uneven shape.

For example, in the case of an example in which a plurality of adhesive portions 3 are arranged in independent dots as shown in FIGS. 5 and 6, the first film 1 is thermally shrunk in both the first direction and the second direction. As a result, the second film 2 produces convex portions in a substantially grid pattern in a plan view as a whole in the intermittent adhesive region (there is a concave portion between the convex portions of the lattice). Further, for example, in the case of an example in which a plurality of adhesive portions 3 are arranged in a strip shape as shown in FIGS. 7 and 8, the first film 1 is thermally shrunk in both the first direction and the second direction. , The second film 2 produces a plan view band-shaped convex portion extending parallel to the second direction as a whole or a plan view band-shaped convex portion extending in a sharp direction with the second direction in the intermittent adhesive region (belt-shaped convex portion). There is a band-shaped recess between the two).

In the entire surface adhesive region, the second film 2 shrinks in the same manner due to the heat shrinkage of the first film 1, and the entire surface adhesive region does not change into an uneven shape and its surface is smooth. When the second film 2 that does not shrink due to the shrinkage force of the first film 1 is used (for example, when the first film 1 having a weak shrinkage stress is used or the second film 2 having a high property of resisting shrinkage). The entire surface adhesive region does not substantially heat-shrink when heated in a microwave oven, but does not change into an uneven shape.

As described above, in the package 10 of the present disclosure, the surface of the packaging bag 89 is smooth (that is, the surface of the packaging bag 89 is a smooth surface) before being heated. On the other hand, when the package 10 is heated, the intermittent adhesive region of the packaging bag 89 can be changed into an uneven shape. According to the packaging body 10, the heat insulating packaging body can be formed by changing the intermittent adhesive region of the packaging bag 89 (packaging film 8) into an uneven shape by heating using a microwave oven. .. That is, in the microwave oven heating package 10 of the present invention, after the microwave oven is heated, the intermittent adhesive region of the packaging bag 89 (packaging film 8) changes in an uneven shape, so that the intermittent adhesive region has a heat insulating property. Express. Since the intermittent adhesive region of the heat-insulating package 10 (heat-insulating package) has an air layer inside the convex portion, the heat of the handle can be relaxed.

Further, since the package 10 changes into an uneven shape after being heated in the microwave oven, it can be easily determined from the appearance whether or not the package 10 has been heated in the microwave oven once. In addition, if a desired design print layer is added to the wrapping film, the unevenness generated after heating in the microwave oven can be combined with the design to give an interesting appearance.

In particular, in the package 10 in which the container 71 having the flange portion 712 is packaged, the upper surface 712a side and the lower surface side of the flange portion 712 are often squeezed by the fingertips. On the other hand, in the package body 10 having the preferred packaging form, an intermittent adhesive region is arranged corresponding to the upper surface 712a of the flange portion 712. Therefore, even if the packaging body 10 is held from above the packaging bag 89 on the upper surface 712a side and the lower surface side of the flange portion 712, it is difficult to feel the heat. There is a gap between the heat-shrinked packaging bag 89, the lower surface of the flange portion 712, and the outer peripheral surface of the container body 711. Therefore, since the intermittent adhesive region is arranged at least in the range corresponding to the upper surface 712a of the flange portion 712, the packaging body 10 is held from above the packaging bag 89 on the upper surface 712a side and the lower surface side of the flange portion 712. However, it becomes difficult to feel the heat.

Further, since the first film 1 having heat shrinkage is laminated on the back surface side of the second film 2, as described above, the second film 2 has a convex shape protruding toward the front surface side when heated in the microwave oven. On the other hand, the concave shape dented on the back surface side changes to a continuous uneven shape. Therefore, a deep and clear uneven surface is formed on the surface of the packaging bag 89 (packaging film 8), and the handle that touches the surface of the packaging bag 89 is less likely to feel the heat.

In the microwave oven heating package 10 of the present invention, the surface of the packaging bag 89 (packaging film 8) is smooth before being microwaved. Therefore, the appearance is good, and fine dust does not accumulate. Further, after heating in the microwave oven, the intermittent adhesive region changes into an uneven shape to form an uneven surface, so that the contact area of the handle becomes small and it becomes easy to hold. Further, since the packaging bag 89 changes in an uneven shape after heating in the microwave oven, it can be easily determined from the appearance whether or not the packaging bag 89 has been heated in the microwave oven once. Further, by providing the desired design printing layer 5 on the packaging film 8, it is possible to manufacture a heat-insulating packaging body having an interesting appearance in combination with the unevenness generated after heating in the microwave oven.

<Modification example 1>
In the above embodiment, the second film 2 is a film having substantially no heat shrinkage, but the second film 2 may also be a film having heat shrinkage. In addition, since the matters described in the above-described embodiment can be applied as they are to the modified example 1 except that the second film 2 has a heat shrinkage property, the drawings relating to the modified example 1 are omitted.

Specifically, as the first film 1, a film that heat-shrinks at least in the first direction is used as in the above embodiment, and a film that heat-shrinks in the first direction and the second direction may be used. Preferably, as the first film 1, a film having heat shrinkage only in the first direction is used. As the second film 2, a film that heat-shrinks only in the second direction or a film that heat-shrinks only in the direction inclined with the first direction is used. In this case, the heat shrinkage rate of the second film 2 in the second direction or the heat shrinkage rate in the tilting direction is not particularly limited, but is preferably 20% or more, more preferably 30% or more, and further. It is preferably 40% or more.

The second film 2 is, for example, a film that heat-shrinks only in the second direction. In this case, since the second film 2 does not substantially heat shrink in a direction other than the second direction, when the package using the packaging film 8 is microwave-heated, the first film 1 moves in at least the first direction. The second film 2 does not substantially heat shrink in the first direction. Therefore, similarly to the above embodiment, the intermittent adhesive region of the packaging bag 89 (packaging film 8) changes in an uneven shape.

Further, the second film 2 is, for example, a film that heat-shrinks only in a direction inclined with respect to the first direction. In this case, since heat shrinkage does not substantially occur in a direction other than the direction of inclination with respect to the first direction, when the package using the packaging film 8 is microwave-heated, the first film 1 is at least first. The second film 2 is heat-shrinked in the direction and the second film 2 is not as heat-shrinked in the first direction as the first film 1, and the intermittent adhesive region of the packaging bag 89 (packaging film 8) changes in an uneven shape.

<Modification 2>
FIG. 20 is a plan view showing a fifth arrangement example of the bonded portion and the non-bonded portion in the intermittent bonding region. As shown in FIG. 20, a plurality of non-adhesive portions 4 may be arranged in independent dots with respect to the intermittent adhesive region of the packaging film 8. The alternate long and short dash line square enclosure in FIG. 20 means that a part of the intermittent adhesive region is taken out, the shaded portion in the square enclosure indicates the adhesive portion 3, and the white background portion indicates the non-adhesive portion 4. ..

In the case of the arrangement example shown in FIG. 20, when viewed along the first direction, which is the heat shrinkage direction of the first film 1, the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the first direction. , There is a portion where the adhesive portion 3 is continuously extended in the first direction. On the other hand, when viewed along the second direction, a portion where the adhesive portion 3 and the non-adhesive portion 4 are alternately arranged in the second direction and a portion where the adhesive portion 3 is continuously extended in the second direction. And there is.

1 1st film 2 2nd film 3 Adhesive part 4 Non-adhesive part 7 Packaged object 71 Container 72 Object to be heated 712 Container flange 8 Container packaging film for microwave oven heating 89 Packaging bag 10 Packaging for microwave oven heating Z Intermittent Adhesive area W Full surface adhesive area

Claims (6)

1. A packaging film for microwave oven heating in which a first film and a second film are laminated and have a sealant layer on the innermost surface.
   The first film is a heat-shrinkable film that heat-shrinks at least in the first direction.
   The second film is a film having substantially no heat shrinkage, a film that heat-shrinks only in the second direction that is orthogonal to the first direction, or a film that heat-shrinks in a direction inclined with the first direction. It is a film that
   Between the layers of the first film and the second film, the adhesive portion in which the layers of the first film and the second film are adhered and the layers of the first film and the second film are not adhered to each other. There is an intermittent adhesive area with an adhesive part,
   In the intermittent adhesive region, the adhesive portion and the non-adhesive portion are alternately arranged in the first direction, and is a packaging film for heating in a microwave oven.
2. The packaging film for heating a microwave oven according to claim 1, wherein the first film is located between the second film and the sealant layer.
3. The packaging film for microwave oven heating according to claim 1 or 2, wherein the non-adhesive portion has a portion that extends continuously in a direction non-parallel to the first direction of the first film.
4. A packaging body for microwave oven heating, in which the object to be heated in a microwave oven is wrapped by the packaging film according to any one of claims 1 to 3.
5. The object to be heated is housed in a container having a flange portion.
   The microwave oven heating package according to claim 4, wherein the container is wrapped with the packaging film so that the intermittent adhesive region of the packaging film corresponds to the upper surface of the flange portion of the container.
6. A method for producing a heat-insulating package, wherein the package for heating a microwave oven according to claim 4 or 5 is heated using a microwave oven to change the intermittent adhesive region of the packaging film into an uneven shape.

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