JP2021066499A - Adhesive label for automatic steam vent promotion for microwave heating packaging container and set member for automatic steam vent promotion for microwave heating packaging container - Google Patents

Abstract

To provide an adhesive label that can readily ventilate steam from various microwave heating packaging containers automatically.SOLUTION: An adhesive label for automatic steam vent promotion for a microwave heating packaging container includes a substrate, an adhesive layer and a separator in this order. The adhesive label includes a heat-generating printing layer in part on an opposite side to the adhesive layer of the substrate or part between the substrate and the adhesive layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive label for promoting automatic steaming of a packaging container for heating a microwave oven, and a set member for promoting automatic steaming of a packaging container for heating a microwave oven.

Microwave oven heating sealing containers that can be cooked in a microwave oven while containing food and other contents are commercially available. When these sealed containers for heating in a microwave oven are cooked using a microwave oven, the internal pressure inside the container increases, and the container deforms or bursts. Therefore, various proposals have been made to prevent this. (For example, Patent Document 1).

The packaging container of Patent Document 1 is provided with an inner seal portion and an outer seal portion, and a non-seal portion is provided between the inner seal portion and the outer seal portion. Further, a part of the inner seal portion is provided. A V-shaped projecting portion is formed so as to project inward, and a ventilation portion for communicating the outside air and the non-sealing portion is formed in a part of the outer sealing portion.

When the packaging container having the configuration of Patent Document 1 is heated in a microwave oven, steam is generated in the main body due to the heating and the internal pressure rises. At this time, the peeling region on the flange portion of the sealing film tends to expand concentrically, and a force for peeling is applied to the sealing film on the protruding portion from the radial direction and the circumferential direction. As a result, the protruding portion is peeled off earlier than the other portions, and the steam is exhausted through the steaming portion. Therefore, it is possible to prevent the contents from being scattered due to the rupture of the packaging container due to the increase in internal pressure.

However, according to the packaging container of Patent Document 1, it is necessary to change the shape of the seal head according to the shapes of the inner seal portion and the outer seal portion, and there is a problem that the cost of the packaging container increases.
As a solution to such a problem, a packaging container of Patent Document 2 has been proposed.

Japanese Unexamined Patent Publication No. 10-236542 Japanese Unexamined Patent Publication No. 2018-193119

The packaging container of Patent Document 2 has a printed portion in which an ink containing a conductive polymer is arranged between a base material layer of a sealing film (lid material) and a heat-adhesive layer, and a non-printed portion in which the ink is not arranged. It is provided, and a ventilation hole is formed by causing peeling of the sealing film or penetration of the sealing film by softening the heat-adhesive layer at a portion having a printed portion in the surface of the packaging container. It emits steam.

However, since the packaging container of Patent Document 2 assumes that the sealing film penetrates by heat, the components of the sealing film may be mixed into the material to be packaged.
Further, in the packaging container of Patent Document 2, since it is necessary to form a printed portion containing a conductive polymer according to the shape of the packaging container, the yield and the production efficiency are lowered when manufacturing a wide variety of packaging containers. Cheap.

The present inventors have completed the present invention as a result of diligent research on a method for easily and automatically steaming various packaging containers for heating in a microwave oven.

That is, the present invention provides the following [1] to [7].
[1] An adhesive label having a base material layer, a pressure-sensitive adhesive layer, and a separator in this order, which is a part of the base material layer on the opposite side of the pressure-sensitive adhesive layer, or the base material layer and the above. An adhesive label for promoting automatic circulation of a packaging container for heating in a microwave oven, which has a heat-generating printing layer in a part between the adhesive layer and the adhesive layer.
[2] The adhesive label for promoting automatic steaming of a packaging container for heating a microwave oven according to [1], wherein the heat-generating printing layer is arranged in a band shape in the plane of the adhesive label.
[3] The adhesive label for promoting automatic steaming of the packaging container for heating in a microwave oven according to [1] or [2], wherein when the width of the heat-generating printing layer is defined as W2, W2 is 8 to 50 mm. ..
[4] When the area of the pressure-sensitive adhesive layer is defined as S3 and the area of the heat-generating printing layer is defined as S2 in the plane of the pressure-sensitive adhesive label, S2 / S3 is 0.3 to 0.9, [1] to The adhesive label for promoting automatic circulation of the packaging container for heating in a microwave oven according to any one of [3].
[5] The adhesive label for promoting automatic steaming of a packaging container for heating a microwave oven according to any one of [1] to [4], wherein the heat-generating printing layer contains a colorant.
[6] Adhesive for promoting automatic steaming of the microwave oven heating packaging container according to any one of [1] to [5], wherein the microwave oven heating packaging container is a packaging container with a lid for microwave oven heating. label.
[7] A packaging container for heating in a microwave oven, a base material layer, an adhesive layer, and a separator are provided in this order, and a part of the base material layer on the opposite side to the pressure-sensitive adhesive layer, or the base material. A set member for promoting automatic circulation of a packaging container for heating a microwave oven, which includes an adhesive label having a heat-generating printing layer in a part between the layer and the pressure-sensitive adhesive layer.

The adhesive label for promoting automatic steaming of the packaging container for heating in a microwave oven and the set member for promoting automatic steaming of the packaging container for heating in a microwave oven of the present invention can easily and automatically steam various packaging containers for heating in a microwave oven. Can be passed through.

It is sectional drawing which shows one Embodiment of the adhesive label of this invention. It is sectional drawing which shows the other embodiment of the adhesive label of this invention. It is sectional drawing which shows the other embodiment of the adhesive label of this invention. It is a top view which looked at the adhesive label of FIG. 1 from the heat generation printing layer side. It is a perspective view which shows the embodiment of the packaging container with a lid for heating a microwave oven which comprises the set member of this invention. FIG. 5 is a perspective view showing an embodiment in a state in which the adhesive label of the present invention is attached to the packaging container with a lid for heating a microwave oven of FIG.

Hereinafter, the adhesive label for promoting automatic steaming of the packaging container for heating microwave oven of the present invention and the set member for promoting automatic steaming of the packaging container for heating microwave oven of the present invention will be described in detail. The notation of the numerical range of "AA to BB" in this specification means "AA or more and BB or less".

[Adhesive label for promoting automatic steaming of packaging containers for heating microwave ovens]
The pressure-sensitive adhesive label for promoting automatic circulation of the packaging container for heating a microwave oven of the present invention is a pressure-sensitive adhesive label having a base material layer, a pressure-sensitive adhesive layer, and a separator in this order, and the pressure-sensitive adhesive of the base material layer. A heat-generating printing layer is provided on a part opposite to the layer or a part between the base material layer and the pressure-sensitive adhesive layer.

In the present specification, the "adhesive label for promoting automatic steaming of the packaging container for heating a microwave oven of the present invention" may be referred to as the "adhesive label of the present invention".

1 to 3 are cross-sectional views showing an embodiment of the adhesive label 30 of the present invention.
The adhesive label 30 of FIGS. 1 to 3 has a base material layer 31, an adhesive layer 32, and a separator 33 in this order.
Further, the adhesive label 30 of FIGS. 1 and 3 has a heat-generating printing layer 34 on a part of the base material layer 31 opposite to the adhesive layer 32, and the adhesive label 30 of FIG. 2 has a base material layer 31. A heat-generating printing layer 34 is provided in a part between the adhesive layer 32 and the pressure-sensitive adhesive layer 32.
Further, the adhesive label 30 of FIGS. 2 and 3 has a pattern layer 35.

FIG. 4 is a plan view of the adhesive label 30 of FIG. 1 as viewed from the heat generation printing layer 34 side. In FIG. 4, the heat-generating printing layer 34 is arranged in a strip shape in the plane of the adhesive label 30.

<Base layer>
The base material layer is preferably one or more selected from a plastic film and a paper base material. When the base material layer is a paper base material, it is preferable because through holes are unlikely to occur in the adhesive label even if the heat generation printing layer generates heat by microwaves.
The base material layer 31 may be only a single layer as shown in FIGS. 1 to 3, but may have a multi-layer structure in which two or more plastic films and / or paper base materials are adhered to each other. When the base material layer contains two or more plastic films and / or paper base materials, a plurality of the same type may be contained, or different types may be contained.

From the viewpoint of heat resistance, it is preferable to use one or more of a polyester film such as polyethylene terephthalate and a polyamide film such as nylon as the base material layer plastic film.

The plastic film may be uniaxially stretched or biaxially stretched. Further, the plastic film may be formed by an inflation method or a melt extrusion coating method.

The thickness of the plastic film is not particularly limited, but is usually about 5 to 50 μm, preferably 10 to 40 μm, and more preferably 12 to 25 μm.
The basis weight of the paper base material is not particularly limited, but is usually ^{about 20} to 200 g / m 2, preferably 50 to 170 g / m ² , and more preferably 70 to 150 g / m ² .

The plastic film preferably has a total light transmittance of JIS K7361-1: 1997 of 85% or more, and more preferably 90% or more. The haze of JIS K7136: 2000 is preferably 1.0% or less, more preferably 0.5% or less, and even more preferably 0.3% or less in the plastic film.
By setting the total light transmittance and the haze within the above ranges, these layers can be easily visually recognized when the pattern layer and / or the heat-generating printing layer is formed on the inner layer side of the plastic film.

<Adhesive layer>
The pressure-sensitive adhesive layer means a so-called "pressure-sensitive adhesive layer". The surface of the pressure-sensitive adhesive layer is exposed by peeling off the separator, and the pressure-sensitive adhesive layer can be attached to a packaging container for heating in a microwave oven.

Examples of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer include rubber-based pressure-sensitive adhesives, acrylic-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, and urethane-based pressure-sensitive adhesives.
Among these, an adhesive having a Young's modulus of ^10-7 dyn / cm ² or less at room temperature and a glass transition temperature of −20 ° C. to −70 ° C. is preferable.

The thickness of the pressure-sensitive adhesive layer is preferably about 1 to 30 μm, more preferably 2 to 125 μm, and even more preferably 3 to 20 μm.

<Heat printing layer>
The heat-generating printing layer is formed on a part of the base material layer opposite to the pressure-sensitive adhesive layer or a part between the base material layer and the pressure-sensitive adhesive layer.
The heat-generating printing layer absorbs microwaves from a microwave oven and generates heat. Therefore, by attaching the adhesive label of the present invention so as to cross a part of the heat-sealed area of the microwave oven heating packaging container, a part of the heat-sealed area is heated by heat when heated in the microwave oven. It can be peeled off and automatically ventilated.
When the heat-generating printing layer absorbs microwaves and generates heat, the pressure-sensitive adhesive layer is not a little affected by heat, and there is a possibility that adverse effects such as a decrease in adhesive strength may occur. Therefore, in the present invention, the heat-generating printing layer is formed not on the entire surface of the adhesive label but on a part of the adhesive label.

In the plane of the adhesive label, the ratio (S2 / S3) of the area S2 of the heat-generating printing layer to the area S3 of the adhesive layer is preferably 0.3 to 0.9, preferably 0.5 to 0.8. More preferably.
By setting S2 / S3 to 0.3 or more, it is possible to easily secure the area of the heat-generating printing layer for generating the amount of heat required for automatic steaming of the packaging container for heating in a microwave oven. Further, by setting S2 / S3 to 0.9 or less, it is possible to easily secure the area of the pressure-sensitive adhesive layer that is not easily affected by the heat generated by the heat-generating printing layer.

The pattern of the heat-generating printing layer in the plane of the adhesive label is not particularly limited, but as shown in FIG. 4, it is preferable that the shape in a plan view is strip-shaped.
By arranging the heat-generating printing layer in a band shape, it is possible to easily form a band-shaped steaming passage in the microwave oven heating packaging container when the heat-generating printing layer is attached to the microwave oven heating packaging container and heated in the microwave oven.
It is also possible to control the amount of steam during automatic steaming by making the heat-generating printing layer trapezoidal in plan view.

When the width of the heat generation printing layer is defined as W2, W2 is preferably 8 to 50 mm, more preferably 10 to 30 mm.
By setting W2 to 8 mm or more, steam can be easily discharged to the outside. Further, by setting W2 to 50 mm or less, it is possible to suppress excessive discharge of steam to the outside and to easily suppress hindrance to cooking of the contents.
The width of the heat-generating print layer may be constant in the plane as shown in FIG. 4, or may be varied in the plane.

When the width of the adhesive label is defined as W1 and the width of the heat generation printing layer is defined as W2, W2 / W1 is preferably 0.3 to 0.9, more preferably 0.5 to 0.8. ..
By setting W2 / W1 to 0.3 or more, it is possible to easily secure the area of the heat-generating printing layer for generating the amount of heat required for automatic steaming of the packaging container for heating in a microwave oven. Further, by setting W2 / W1 to 0.9 or less, it is possible to easily prevent the heat-generating printing layer from becoming unnecessarily high temperature and excessively discharging steam to the outside.

The width of the adhesive label (W1) and / or the width of the heat-generating printing layer (W2) may be constant in the plane or may be varied in the plane. When W1 and / or W2 fluctuates in the plane, W1 and W2 may be extracted at the same position in the in-plane length direction and W2 / W1 may be calculated.

Area S2 of the heat generating print layer is preferably 1 cm ² or more, more preferably 1～12Cm ^2, further preferably 3~8cm ^2.
By setting the area of the heat-generating printing layer to 1 cm ² or more, it is possible to easily apply the heat-generating amount required for automatic steaming of the packaging container for heating in a microwave oven. Further, by setting the area of the heat-generating printing layer to 12 cm ² or less, it is possible to prevent the area for peeling and steaming from becoming excessive, which hinders the degree of cooking of the contents.

The thickness of the heat-generating printing layer is preferably 0.1 to 5 μm, more preferably 0.2 to 3 μm.
By setting the thickness of the heat-generating printing layer to 0.1 μm or more, it is possible to easily apply the amount of heat generated for automatic steaming of the packaging container for heating in a microwave oven. Further, by setting the thickness of the heat-generating printing layer to 5 μm or less, it is possible to prevent the heat-generating printing layer from becoming unnecessarily high in temperature, thereby suppressing deformation of the adhesive label and formation of through holes in the adhesive label. It can be done easily.

The heat-generating printing layer is a layer that absorbs microwaves to generate heat, and includes a material that absorbs microwaves.
Examples of the material that absorbs microwaves include conductive particles and a conductive polymer. Among these, the conductive polymer is suitable because it has good transparency of visible light and is less likely to generate sparks due to microwaves.

Examples of the conductive particles include carbon black, silver, aluminum and ITO (indium tin oxide).

As the conductive polymer, one or more compounds selected from polythiophenes, polypyrroles, polyanilines, polyacetylenes, polyphenylenes, polyphenylene vinylenes, polyacenes and polythiophene vinylenes are preferable. Further, when a conductive polymer is used, it is more preferable to further contain a dopant.
Dopants include halogens, Lewis acids, protonic acids, organic carboxylic acids, transition metal halides, electrolyte anions, organic cyano compounds, quinones, alkali metals, alkaline earth metals, amino acids, nucleic acids, surfactants, dyes, Included are alkylammonium ions and quaternary phosphonium salts.

When conductive particles are used as the conductive agent, the heat-generating printing layer preferably contains a binder resin. Further, when a conductive polymer is used as the conductive agent, another resin may be contained in order to adjust the conductivity.

Binder resins used together with conductive particles and resins used together with conductive polymers include polyolefin resins such as polyethylene resins and chlorinated polypropylene resins, poly (meth) acrylic resins, polyvinyl chloride resins, and poly. Vinyl acetate resin, vinyl chloride-vinyl acetate copolymer, polystyrene resin, styrene-butadiene copolymer, vinylidene fluoride resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyvinyl butyral resin, polybutadiene resin, Polyester resin, polyamide resin, alkyd resin, epoxy resin, unsaturated polyester resin, thermosetting poly (meth) acrylic resin, melamine resin, urea resin, polyurethane resin, phenol resin, xylene Fiber-based resins, maleic acid resins, fibrous resins such as nitrocellulose and ethylcellulose, acetylbutylcellulose and ethyloxyethylcellulose, rubber-based resins such as rubber chloride and cyclized rubber, petroleum-based resins, natural resins such as rosin and casein Can be mentioned.

The heat-generating printing layer further comprises, if necessary, for example, colorants, fillers, stabilizers, plasticizers, antioxidants, UV absorbers, light stabilizers, dispersants, thickeners, desiccants, lubricants and Any additive such as a cross-linking agent can be added. Among these additives, a colorant is preferable. That is, the heat-generating printing layer preferably contains a colorant.
Since the heat-generating printing layer contains a colorant, the portion having the heat-generating printing layer can be visually recognized in the surface of the adhesive label, and the heat-generating printing layer of the adhesive label is exposed to the heat-sealed area of the microwave heating packaging container. It can be easily bonded so that the areas having the above are in an appropriate positional relationship. From the viewpoint of exerting such an effect, when the base material layer is a paper base material, it is preferable to form a heat-generating printing layer on the side opposite to the pressure-sensitive adhesive layer of the paper base material.

As the colorant for the heat-generating printing layer, the same colorants as those exemplified as the colorant for the pattern layer described later can be used. Among these colorants, a black colorant that easily imparts visibility with a small amount is preferable, and carbon black is more preferable.
When the heat-generating printing layer contains a colorant, the content of the colorant is preferably 0.1 to 10% by mass, more preferably 0.3 to 3% by mass, based on the total solid content of the heat-generating printing layer. preferable.

In some embodiments, the heat-generating printing layer is preferably formed on the side opposite to the pressure-sensitive adhesive layer of the base material layer.
For example, when the adhesive label is attached to the packaging container for heating in a microwave oven, it is preferable that the portion having the heat-generating printing layer can be visually recognized from the outer layer side of the adhesive label. The part having the heat generation printing layer cannot be visually recognized from the outer layer side of the adhesive label. Therefore, in the case of the embodiment in which the base material layer contains paper, it is preferable to form the heat-generating printing layer on the side opposite to the pressure-sensitive adhesive layer of the base material layer.
Paper also absorbs microwaves from microwave ovens. Therefore, in the case of the embodiment in which the lid material and / or the container body of the microwave oven heating packaging container to which the label is attached contains paper and the base material layer of the label contains paper, the heat generating printing layer absorbs microwaves. Efficiency may be reduced. Therefore, in the case of the embodiment, it is preferable that the heat-generating printing layer is formed on the side opposite to the pressure-sensitive adhesive layer of the base material layer.

If the adhesion of the heat-generating printing layer is not good, an anchor coat layer may be provided on the layer (for example, the base material layer) forming the heat-generating printing layer.

<Separator>
The separator is preferably one or more selected from a plastic film and a paper base material.
Examples of the plastic film and the paper base material as the separator include those similar to those exemplified as the plastic film and the paper base material of the base material layer. In order to improve the releasability from the pressure-sensitive adhesive layer, the plastic film and the paper base material as the separator are preferably those which have been released with a silicone-based releasing agent or the like.
Further, since the separator is not required to have heat resistance, the plastic film as the separator can be used even if it is inferior in heat resistance.

The separator is preferably made of the same material as the base material layer. Specifically, when the base material layer is a plastic film, the separator is also preferably a plastic film, and the type of resin constituting the plastic film is more preferably the same type. When the base material layer is a paper base material, it is preferable that the separator is also a paper base material. By using the same type of material for the separator and the base material layer, it is possible to easily suppress curling of the adhesive label.
Further, it is preferable that the base material layer and the separator have the same thickness of the plastic film or the basis weight of the paper base material. The same thickness or basis weight means that the thickness of the plastic film of the base material layer is T1, the thickness of the plastic film of the separator is T2, the basis weight of the paper base material of the base material layer is D1, and the tsubo of the paper base material of the separator. When the amount is defined as D2, it means that T1 / T2 is 0.8 to 1.2 and D1 / D2 is 0.8 to 1.2.

<Pattern layer>
The adhesive label of the present invention may have a pattern layer.
The position of the pattern layer may be appropriately determined in consideration of the light transmission of the base material layer and the heat-generating printing layer.

For example, when a base material layer having low light transmission such as paper or an opaque plastic film is provided, the pattern layer is preferably arranged on the outer layer side of the base material layer having low light transmission. Further, when a base material layer having high light transmission such as a transparent plastic film is provided, it is preferable to arrange the pattern layer on the inner layer side of the base material layer having high light transmission from the viewpoint of protecting the pattern layer. Further, when a plurality of base material layers are provided, the position of the pattern layer may be appropriately determined in consideration of the light transmittance of each base material layer and the like.
In FIG. 2, the pattern layer 35 is arranged on the inner layer side of the base material layer 31. In this case, the base material layer 31 is a base material layer having high light transmission.

Further, when the light transmission of the heat-generating printing layer is low, it is preferable that the pattern layer is arranged on the outer layer side of the heat-generating printing layer. On the other hand, when the light transmission of the heat-generating printing layer is high, the pattern layer may be arranged on either the inner layer side or the outer layer side of the heat-generating printing layer.
The heat-generating printing layer usually has good light transmission when a conductive polymer is used as a material for absorbing microwaves, and even when conductive particles are used as a material for absorbing microwaves. As long as it does not contain an excessive amount of conductive particles having a particle size larger than that of visible light, it has a predetermined light transmittance. Therefore, the positional relationship between the pattern layer and the heat-generating printing layer is not limited unless the heat-generating printing layer has an extreme configuration.

The pattern layer can form a pattern by one or more combinations selected from characters, figures, symbols, patterns, patterns, solid printing, and the like. The pattern layer is not limited to a single layer, and may be a plurality of layers of two or more layers.
The pattern layer 35 may be formed on the entire surface of the adhesive label 30 as shown in FIG. 2, or may be formed on a part of the surface of the adhesive label 30 as shown in FIG.

The pattern layer mainly contains a colorant and a binder resin.
Colorants include white pigments such as titanium dioxide, barium sulfate, magnesium oxide, calcium carbonate, zinc oxide and lead white; black pigments such as carbon black, titanium black and iron black; yellow lead, titanium yellow, petals and cadmium. Colored inorganic pigments such as red, ultramarine blue and cobalt blue; chromatic organic pigments such as quinacridone red, isoindolinone yellow and phthalocyanine blue; brilliant materials such as pearl pigments and metal scales; dyes and the like. Species or two or more species can be used.
Examples of the binder resin include those similar to the binder resin exemplified in the heat-generating printing layer.

The content of the colorant in the pattern layer is not particularly limited, but is preferably 5 to 70% by mass, more preferably 15 to 65% by mass, and 20% by mass of the total solid content of the pattern layer. It is more preferably ~ 60% by mass.

When a bright pigment is contained as the colorant, the pearl pigment is preferable as the bright pigment from the viewpoint of microwave oven resistance.
Examples of the pearl pigment include white pearl pigment, interfering pearl pigment, colored pearl pigment and the like.

The average length of the pearl pigment is preferably 5 to 70 μm, more preferably 10 to 40 μm.
The average length of the pearl pigment and the average length of the metal scales are the average values of the lengths of any 20 particles (pearl pigment or metal scales) observed with an optical microscope or an electron microscope from the plane direction of the adhesive label. Is required as. The length of one pearl pigment and the metal scale means the maximum length of one pearl pigment and the metal scale in the plane direction.

The average thickness of the pearl pigment is preferably 0.01 to 1 μm, more preferably 0.02 to 0.7 μm, and even more preferably 0.05 to 0.5 m.
The average thickness of the pearl pigment and the metal scale is determined as the average value of the thickness of any 20 particles (pearl pigment or metal scale) obtained by observing the cross section of the adhesive label with an optical microscope or an electron microscope. The thickness of one pearl pigment and metal scale is obtained by dividing a cross-sectional image of one pearl pigment and metal scale into five regions having equal lengths in the length direction, and the thickness of the central portion of each region ( _{t 1, t 2, t 3} , t 4, t 5) were _measured, it means an average of the t 1 ~t _5.

The content of the pearl pigment is preferably 40 to 90% by mass, more preferably 50 to 85% by mass, and further preferably 50 to 85% by mass of the total solid content of the pattern layer from the viewpoint of obtaining sufficient glossiness. Is 60 to 80% by mass.

Examples of the material of the metal scale as the glitter pigment include metals and alloys such as aluminum, gold, silver, brass, titanium, chromium, nickel, nickel chromium, and stainless steel.
The metal scale is obtained, for example, obtained by peeling a metal thin film formed by vacuum-depositing the metal or alloy on a plastic film from the plastic film, crushing and stirring the peeled metal thin film, or a powder of the metal or alloy. And a solvent are mixed, and the powder obtained by spreading and / or pulverizing the powder with a medium stirring mill, a ball mill, an attritor, or the like, or a resin-coated surface thereof can be used. it can.

The metal scales preferably have an average length of 1 to 50 μm, more preferably 2 to 30 μm, still more preferably 5 to 20 μm, from the viewpoint of uniform dispersibility in the pattern layer. Further, from the viewpoint of obtaining handleability and high metallic luster, the average thickness is preferably 0.01 to 5 μm, more preferably 0.02 to 3 μm, and further preferably 0.05 to 1 μm. The aspect ratio (average length / average thickness) of the metal scales is preferably 15 to 500.

The content of the metal scales in the pattern layer is preferably 3% by mass or more and 50% by mass or less of the total solid content of the pattern layer from the viewpoint of the balance between imparting brilliance and microwave oven resistance. It is more preferably 40% by mass or less, and further preferably 10% by mass or more and 30% by mass or less.

The pattern layer can be formed, for example, by applying a pattern layer forming ink containing a material constituting the pattern layer onto a base material layer or an intermediate base material, drying, or the like.

The thickness of the pattern layer is not particularly limited, and is preferably about 0.3 to 5.0 μm, more preferably 0.5 to 3.0 μm.

<Intermediate base material layer>
The intermediate base material layer is provided between the base material layer and the pressure-sensitive adhesive layer as necessary for the purpose of improving the strength and processability of the pressure-sensitive adhesive label, adjusting the texture of the pressure-sensitive adhesive label, and the like. It is a layer. Examples of the constituent material of the intermediate base material layer include a plastic film and a paper base material.

As the plastic film and the paper base material as the intermediate base material layer, the same ones as those of the plastic film and the paper base material as the base material layer described above can be used.

Considering heating in a microwave oven, the intermediate base material layer preferably has excellent heat resistance. Specific examples of the intermediate base material layer having excellent heat resistance include paper and the plastic film having excellent heat resistance exemplified in the base material layer.
When the intermediate base material layer is provided, it is preferable to have an adhesive layer between the base material layer and the intermediate base material layer.

<Layer structure of adhesive label>
An embodiment of the layer structure of the adhesive label is shown below. In the following (A1) to (A12), the layer on the left side is the outer layer side, and "/" indicates the boundary of each layer.
(A1) Heat-generating printing layer / base material layer (paper) / adhesive layer / separator (paper)
(A2) Heat generation printing layer / picture layer / base material layer (paper) / adhesive layer / separator (paper)
(A3) Heat generation printing layer / base material layer (plastic film) / adhesive layer / separator (paper)
(A4) Heat generation printing layer / picture layer / base material layer (plastic film) / adhesive layer / separator (paper)
(A5) Heat-generating printing layer / base material layer (plastic film) / adhesive layer / separator (plastic film)
(A6) Heat generation printing layer / picture layer / base material layer (plastic film) / adhesive layer / separator (plastic film)
(A7) Heat-generating printing layer / base material layer (paper) / adhesive layer / intermediate base material layer (plastic film) / adhesive layer / separator (paper)
(A8) Heat-generating printing layer / picture layer / base material layer (paper) / adhesive layer / intermediate base material layer (plastic film) / adhesive layer / separator (paper)
(A9) Base material layer (plastic film) / heat generation printing layer / adhesive layer / separator (paper)
(A10) Base material layer (plastic film) / picture layer / heat-generating printing layer / adhesive layer / separator (paper)
(A11) Base material layer (plastic film) / heat generation printing layer / adhesive layer / separator (plastic film)
(A12) Base material layer (plastic film) / picture layer / heat-generating printing layer / adhesive layer / separator (plastic film)

<Use, etc.>
The adhesive label of the present invention is attached so as to cross a part of the heat-sealed area of the packaging container for heating in a microwave oven, so that when heated in a microwave oven, a part of the heat-sealed area is peeled off by heat. It can be automatically steamed.
In particular, the adhesive label of the present invention is effective for automatically steaming a packaging container with a lid for heating a microwave oven.
Further, since the adhesive label of the present invention is used by being bonded to the outer layer side of the packaging container, the material constituting the packaging container penetrates by heat due to the heat generated in the heat-generating printing layer of the adhesive label during heating in a microwave oven. Things are unlikely to happen.

[Set member for promoting automatic steaming of packaging container for heating microwave oven]
The set member for promoting automatic circulation of the packaging container for heating in a microwave oven of the present invention comprises the packaging container for heating in a microwave oven, a base material layer, an adhesive layer, and a separator in this order. It includes an adhesive label having a heat-generating printing layer in a part on the opposite side of the pressure-sensitive adhesive layer or a part between the base material layer and the pressure-sensitive adhesive layer.
In the present specification, the "set member for promoting automatic steaming of the packaging container for heating the microwave oven of the present invention" may be referred to as the "set member of the present invention".

<Packaging container for heating in a microwave oven>
Examples of the packaging container for heating a microwave oven include a pouch and a container with a lid. Among these, a container with a lid is preferable from the viewpoint of ease of attaching the adhesive label and ease of automatic steaming by the adhesive label.

Examples of the pouch include a three-sided seal, a four-sided seal flat bag, a standing pouch, a gusset bag, a pillow bag, and the like. These pouches have a heat-sealed region formed by heat-sealing a part of the sealant layer of one or more sheet materials.
The container with a lid includes a container body for accommodating the contents and a lid material having a base material layer and a sealant layer. The container body has a flange, and at least a part of the flange and the lid material are provided. It has a heat-sealed region formed by heat-sealing the sealant layer of the above.

FIG. 5 is a perspective view showing an embodiment of a packaging container with a lid for heating a microwave oven.
The packaging container 50 with a lid for heating a microwave oven in FIG. 5 includes a container body 51 and a lid material 52 for sealing the container body. Further, the container body 51 has an opening on the upper surface and a flange 51a on the outer peripheral edge of the opening. Further, as shown in FIG. 5, the opening is sealed by a heat-sealing region H in which the flange and the sealant layer are heat-sealed (the shaded portion in FIG. 5 is the heat-sealing region H). Reference numeral 52a in FIG. 5 indicates a gripping portion of the lid material.

《Container body》
The container body has a flange at the opening. The container body may be made of paper or plastic.

When the container body is made of paper, the type of paper is not particularly limited. The basis weight of the paper is not particularly limited, but the paper forming the body ^{is preferably about 150 to 400 g / m 2} , and the paper forming the bottom is about ^{150 to 250 g / m 2.} Is preferable.
When paper is used, it is preferable to have a resin layer on both sides or one side of the paper from the viewpoint of protecting the material to be packaged and from the viewpoint of suppressing leakage of the liquid material to be packaged. Further, from the viewpoint of heat insulating property, the resin layer may be foamed.
Examples of the resin constituting the resin layer include polyolefin resins such as polyethylene and polypropylene, polyester, ethylene-vinyl acetate copolymer and the like, and polyethylene is preferable.
The thickness of the resin layer is preferably about 15 to 60 μm. The thickness of the resin layer on the outer layer side of the paper is preferably 15 to 20 μm, and the thickness of the resin layer on the inner layer side of the paper is preferably 25 to 60 μm.

Further, the paper may be made by laminating a plastic film for the purpose of increasing the strength and gas barrier property of the container body. Further, in order to further enhance the gas barrier property, the plastic film is preferably a vapor-deposited film.

The paper container body can be manufactured, for example, by appropriately processing and adhering the paper forming the body and the paper forming the bottom. The flange can be formed, for example, by bending the paper forming the body.

When the container body is made of plastic, examples of the plastic include polyethylene, polypropylene, polyethylene terephthalate and the like. Among these, polypropylene is preferable from the viewpoint of oil resistance and heat resistance to the oil contained in the contents. The plastic constituting the container body may be a single layer or a multi-layer.
The plastic container body can be manufactured, for example, by vacuum forming or vacuum forming a sheet-shaped plastic film, injection molding of a thermoplastic, or the like.

The container body has an opening on the upper surface. Further, the container body is provided with a flange on the outer peripheral edge of the opening.
The shape of the container body may be any one having the above-mentioned shape, and the shape beyond that is not limited. For example, the container body of FIG. 5 has a substantially circular bottom and opening, but the bottom and opening may have a shape other than a circle such as an ellipse or a quadrangle. Further, although the container body of FIG. 5 has a larger opening than the bottom portion, the sizes of the bottom portion and the opening portion may be substantially the same, or the opening portion may be smaller than the bottom portion. .. Further, although the container body of FIG. 5 has a flat bottom, the container body may have legs. Further, although the flange of the container body in FIG. 5 is flat, the shape of the flange may be annular.
The diameter and depth of the container body may be appropriately determined in consideration of the type and amount of the contents, the design, and the like.

The width of the flange of the container body is preferably about 2 to 15 mm from the viewpoint of sealing property and easy peeling property.

The flange may have a protruding portion that protrudes toward the center of the container body. By having a protruding portion in a part of the flange, when heating in a microwave oven, the load based on the internal pressure of the sealing container is concentrated on the portion corresponding to the protruding portion in the heat seal region, and the portion is automatically ventilated to have the internal pressure. Can be easily escaped. However, considering that it is necessary to change the shape of the seal head when the flange has a protruding portion and that the adhesive label of the present invention can be used for automatic ventilation without the protruding portion, the flange protrudes. It is preferable not to have a part.

《Lid material》
The lid material has a base material layer and a sealant layer.
The sealant layer is arranged on the inner layer side of the base material layer (the side closer to the container body than the base material layer).

-Base layer-
The base material layer of the lid material is preferably one or more selected from a plastic film and a paper base material.
Examples of the plastic film and the paper base material as the base material layer of the lid material include those similar to those exemplified as the base material layer of the adhesive label.

-Sealant layer-
The sealant layer is partially heated by a seal head or the like to form a heat seal region H in close contact with the flange, and has a role of sealing the opening of the container body.
The sealant layer may be a single layer of the seal layer, but is preferably composed of a laminate of the core layer and the seal layer. The core layer contacts the substrate layer and the seal layer contacts the flange.

(Seal layer)
The seal layer is partially heated by a seal head or the like to be in close contact with the flange to form a heat seal region. Therefore, the seal layer is preferably made of a thermoplastic resin having a heat-seal property.
Further, the seal layer preferably has an easy peeling property that can be easily peeled off from the container body. In addition, in this specification, "good easy peeling property" does not simply mean that the peeling strength is weak, and the peeling strength at the time of peeling is too strong while having an adhesive strength enough to guarantee the sealing property. It means that there is nothing.
The resin constituting the seal layer can be appropriately selected from general-purpose resins in consideration of the material constituting the container body and the material of the core layer.

(Core layer)
The core layer is preferably made of a thermoplastic resin.
The resin constituting the core layer can be appropriately selected from general-purpose resins in consideration of the material of the base material layer and the material of the seal layer.

The thickness of the sealant layer can be appropriately determined from the viewpoint of easy peelability, and the range thereof is, for example, about 1 to 100 μm.
When the sealant layer is composed of a seal layer and a core layer, the thickness ratio of the two can be appropriately adjusted according to the purpose.

-Other layers-
The lid material may have other layers such as a pattern layer, a gas barrier layer, an intermediate base material layer and an adhesive layer. Of these, the pattern layer is preferably arranged on the outer layer side of the base material layer or between the base material layer and the sealant layer.

《Heat seal area》
The container with a lid has a heat-sealed region in which at least a part of the flange of the container body and the sealant layer of the lid material are heat-sealed. The heat-sealed area allows the lidded container to seal the contents.

As shown in FIG. 5, the heat seal region is preferably formed continuously in a strip shape or a linear shape so as to go around the flange once.
The area of the heat seal region may match the area of the flange. In other words, the sealant layer may be heat-sealed on all of the flanges. On the other hand, it is not necessary to heat-seal the sealant layer to a part of the flange so that the area of the heat-sealed region and the area of the flange do not match.

The width of the heat seal region is preferably 10% to 100% of the width of the flange, and more preferably 20 to 80%.

"Contents"
The contents to be stored in the container body are not particularly limited, and may be a liquid substance or a solid substance.

<Adhesive label>
The pressure-sensitive adhesive label constituting the set member of the present invention has a base material layer, a pressure-sensitive adhesive layer, and a separator in this order, and is a part of the base material layer on the opposite side to the pressure-sensitive adhesive layer, or the group. A heat-generating printing layer is provided in a part between the material layer and the pressure-sensitive adhesive layer.
As the adhesive label, the adhesive label of the present invention described above can be used.

In the set member of the present invention, the adhesive label is used by being bonded so as to cross a part of the heat seal region of the packaging container for heating in a microwave oven. By attaching the adhesive label so as to cross a part of the heat-sealed area of the microwave oven heating packaging container and then heating it in the microwave oven, a part of the heat-sealed area is peeled off by heat and automatically ventilated. be able to.
Note that FIG. 6 shows a state in which the adhesive label 30 is attached so as to cross a part of the heat seal region H of the packaging container for heating the microwave oven of FIG.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

1. 1. Preparation of Adhesive Label [Example 1]
A pattern layer forming ink was gravure-printed on the entire surface of one surface of a substrate layer (paper substrate having a basis weight of 150 g / m ^{2) and dried to form a pattern layer having a dry film thickness of 1.5 μm.}
Next, an ink containing a conductive polymer and a colorant (manufactured by Tokyo Ink Co., Ltd., product number MW heat agent) is gravure-printed on a part of the pattern layer and dried to form a band-shaped heat-generating printing layer having a thickness of 0.5 μm. Formed in.
Next, a double-sided adhesive laminate for mounting having an acrylic pressure-sensitive adhesive layer (thickness 20 μm) and a separator was prepared on a paper substrate having releasability. The separator is peeled off from the laminate, and the exposed adhesive layer is attached to the entire surface of the base material layer on the side opposite to the surface on which the pattern layer is formed. An adhesive label of Example 1 having an adhesive layer and a separator (paper substrate having releasability) in this order was obtained.
The adhesive label of the example has an adhesive label width (W1) of 25 mm, a heat-generating printing layer width (W2) of 15 mm, and an adhesive label length (= heat-generating printing layer length) of 18 mm. It was.

2. Evaluation 2-1. Preparation of Microwave Oven Heating Packaging Containers The following commercially available microwave oven heating packaging containers A to C were prepared.
Each of the containers A to C has a container body for accommodating the contents and a lid material having a base material layer and a sealant layer, and the container body has a flange, and at least a part of the flange. It has a heat-sealed region formed by heat-sealing the sealant layer of the lid material.
<Container A>
Container body: Made of plastic (opening shape is approximately circular, flange inner diameter is 90 mm, outer diameter is 100 mm, body depth is 95 mm, contents: frozen pilaf is 150 g), lid material base layer: plastic film < Container B>
Container body: Made of paper (opening shape is approximately circular, flange inner diameter is 90 mm, outer diameter is 100 mm, body depth is 95 mm, contents: frozen pilaf is 150 g), lid material base layer: paper <container C>
Container body: Made of plastic (the shape of the opening is approximately square, the shape along the outer edge is 90 mm in length, 140 mm in width, the width of the flange is 10 mm, the depth of the body is 30 mm, the contents: 80 g of grilled fish), the base of the lid material Material layer: Plastic film

2-2. Preparation of Packaging Container for Microwave Oven Heating The separator of the adhesive label of Example 1 was peeled off, and the exposed surface on the adhesive layer side was attached so as to cross a part of the heat-sealed region of the containers A to C. In this state, the mixture was heated in a tableless microwave oven having an output of 600 W for 120 seconds, and it was visually evaluated whether or not the lid material was partially peeled off and automatically steamed. Further, the containers A to C are heated for 120 seconds in a tableless microwave oven having an output of 600 W without the adhesive label of Example 1 being attached, and the lid material is partially peeled off to automatically steam. Whether or not it was visually evaluated. The results are shown in Table 1.
A: Automatic steaming.
C: Those that do not automatically ventilate.

From the results shown in Table 1, it can be confirmed that the adhesive label for promoting automatic steaming of the packaging container for heating the microwave oven of the example can easily automatically steam various packaging containers for heating the microwave oven.
On the other hand, in the comparative example, automatic steaming did not occur, and the contents were projected or the container was deformed due to heat.
The tests were performed 20 times for each Example and each Comparative Example, and the results were the same in all cases.

30 Adhesive label 31 Base material layer 32 Adhesive layer 33 Separator 34 Heat generation printing layer 35 Picture layer 50 Packaging container with lid for microwave heating 51 Container body 51a Flange 52 Lid material 52a Holding part H Heat seal area

Claims (7)

An adhesive label having a base material layer, a pressure-sensitive adhesive layer, and a separator in this order, which is a part of the base material layer on the opposite side of the pressure-sensitive adhesive layer, or the base material layer and the pressure-sensitive adhesive layer. An adhesive label for promoting automatic circulation of a packaging container for heating in a microwave oven, which has a heat-generating printing layer in a part between the and. The adhesive label for promoting automatic steaming of a packaging container for heating a microwave oven according to claim 1, wherein the heat-generating printing layer is arranged in a band shape in the plane of the adhesive label. The adhesive label for promoting automatic steaming of a packaging container for heating a microwave oven according to claim 1 or 2, wherein when the width of the heat-generating printing layer is defined as W2, W2 is 8 to 50 mm. Any of claims 1 to 3, wherein S2 / S3 is 0.3 to 0.9 when the area of the pressure-sensitive adhesive layer is defined as S3 and the area of the heat-generating printing layer is defined as S2 in the plane of the pressure-sensitive adhesive label. The adhesive label for promoting automatic circulation of the packaging container for heating in a microwave oven according to item 1. The adhesive label for promoting automatic steaming of a packaging container for heating a microwave oven according to any one of claims 1 to 4, wherein the heat-generating printing layer contains a colorant. The adhesive label for promoting automatic circulation of the microwave oven heating packaging container according to any one of claims 1 to 5, wherein the microwave oven heating packaging container is a packaging container with a lid for microwave oven heating. Packaging container for microwave heating and
A base material layer, a pressure-sensitive adhesive layer, and a separator are provided in this order, and a part of the base material layer on the opposite side to the pressure-sensitive adhesive layer, or one between the base material layer and the pressure-sensitive adhesive layer. Including an adhesive label having a heat-generating printing layer on the part,
A set member for promoting automatic steaming of packaging containers for heating microwave ovens.

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