JP2021066503A - Lid-attached container to be heated in microwave oven - Google Patents

Abstract

To provide a lid-attached container which can increase certainty that the lid member is partially peeled off so as to pass steam in the case that the container body is made of paper.SOLUTION: A lid-attached container comprises: a paper container body; and a lid member for sealing the container body. The lid member comprises: a base material layer; a sealant layer; and a heat-generating printing layer in a part between the base material layer and the sealant layer or in a part of the base material on a side opposite to sealant layer. The lid-attached container is sealed with a heat-sealed region formed through heat-seal of a flange and the sealant layer. The lid-attached container is arranged with the heat-generating printing layer in following Region 1 and Region 2, where the <Region 1> is a region connecting a part of an outer peripheral edge of the flange in a circumferential direction to a part of an inner peripheral edge of the flange in the circumferential direction, and the <Region 2> is a region continuous from the Region 1 and inside the inner peripheral edge of the flange.SELECTED DRAWING: Figure 3

Description

The present invention relates to a container with a lid 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, in the embodiment in which the sealing film of the packaging container of Patent Document 2 is peeled off, there are many cases where the sealing film does not peel off at the portion having the printed portion when heated by a microwave oven. When such a case occurs, the internal pressure of the container increases, the container may be deformed, or the contents may explode.
Further, in the embodiment in which the sealing film of the packaging container of Patent Document 2 is penetrated, the components of the sealing film may be mixed in the material to be packaged.

As a result of investigating the cause of the case where the sealing film does not peel off at the portion having the printed portion containing the conductive polymer in the embodiment of peeling off the sealing film of the packaging container of Patent Document 2, the present inventors have investigated. It has been found that this case tends to occur when the container body is paper (particularly when the container body is paper and the material to be packaged is liquid).
As a result of further studies, the present inventors have found a structure in which the sealing film (lid material) is partially peeled off to increase the certainty of steaming when the container body is paper, and complete the present invention. I came to do it.

That is, the present invention provides the following [1] to [5].
[1] A container with a lid having a flange at the opening and provided with a paper container body for accommodating the contents and a lid material for sealing the container body, and the lid material is a base material. A container with a lid, which has a layer and a sealant layer, and also has a heat-generating printing layer on a part between the base material layer and the sealant layer or a part of the base material layer on the side opposite to the sealant layer. Is sealed by a heat-sealed region in which at least a part of the flange and the sealant layer are heat-sealed, and when the container with a lid is viewed in a plan view, the heat-generating printing layer is formed into the following region 1 and region. A container with a lid for heating a microwave oven, which is provided in 2.
<Area 1>
A region connecting a part of the outer peripheral edge of the flange in the circumferential direction to a part of the inner peripheral edge of the flange in the circumferential direction.
<Area 2>
A region continuous from the region 1 and inside the inner peripheral edge of the flange.
[2] The container with a lid for heating a microwave oven according to [1], wherein the heat-generating printing layer in the region 2 has a width of 1 to 15 mm.
[3] In [1] or [2], the lid material protrudes outward from the outer peripheral edge of the flange, and when the container with a lid is viewed in a plan view, the heat-generating printing layer is further provided in the following region 3. The described container with a lid for heating in a microwave oven.
<Area 3>
A region continuous from the region 1 and outside the outer peripheral edge of the flange.
[4] The container with a lid for heating a microwave oven according to [3], wherein the heat-generating printing layer in the region 3 has a width of 0.5 to 10 mm.
[5] D1 which is the extending direction from the outside to the inside of the heat generating printing layer when the container with a lid is viewed in a plan view and D2 which is a direction orthogonal to the tangent line of the inner peripheral edge of the flange are substantially parallel. , [1] to [4], the container with a lid for heating the microwave oven.

The container with a lid for heating a microwave oven of the present invention can increase the certainty that the lid material is partially peeled off and steamed.

It is a perspective view which shows one Embodiment of the container with a lid for heating a microwave oven of this invention. FIG. 1 is a cross-sectional view taken along the line I-I'in FIG. It is a top view explaining one Embodiment of the arrangement of the heat seal region and the heat generation printing layer of the container with a lid for heating a microwave oven of this invention. It is a top view explaining one Embodiment of the arrangement of the heat seal region and the heat generation printing layer of the container with a lid for heating a microwave oven of this invention. It is a top view explaining one Embodiment of the arrangement of the heat seal region and the heat generation printing layer of the container with a lid for heating a microwave oven of this invention. It is a top view explaining one Embodiment of the arrangement of the heat seal region and the heat generation printing layer of the container with a lid for heating a microwave oven of this invention. It is a partially enlarged view of FIG. It is sectional drawing which shows one Embodiment of the lid material which constitutes the container with a lid for heating a microwave oven of this invention. It is sectional drawing which shows one Embodiment of the lid material which constitutes the container with a lid for heating a microwave oven of this invention.

Hereinafter, the container with a lid for heating the 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".

[Container with lid for heating microwave oven]
The container with a lid for heating a microwave oven of the present invention is a container with a lid having a flange at the opening, a container body made of paper for accommodating the contents, and a lid material for sealing the container body. The lid material has a base material layer and a sealant layer, and generates heat in a part between the base material layer and the sealant layer or a part of the base material layer on the side opposite to the sealant layer. The container with a lid having a printing layer is sealed by a heat-sealed region in which at least a part of the flange and the sealant layer are heat-sealed, and when the container with a lid is viewed in a plan view, the container is sealed. The heat-generating printing layer is provided in the following areas 1 and 2.
<Area 1>
A region connecting a part of the outer peripheral edge of the flange in the circumferential direction to a part of the inner peripheral edge of the flange in the circumferential direction.
<Area 2>
A region continuous from the region 1 and inside the inner peripheral edge of the flange.

FIG. 1 is a perspective view showing an embodiment of a container with a lid for heating a microwave oven of the present invention, and FIG. 2 is a cross-sectional view taken along the line I-I'of FIG.
The container 100 with a lid for heating the microwave oven of FIGS. 1 and 2 includes a container body 10 and a lid material 20 for sealing the container body. Further, the container body 10 is provided with an opening 11 on the upper surface thereof, and has a flange 12 on the outer peripheral edge of the opening 11. Further, as shown in FIG. 1, the opening 11 is sealed by a heat-sealing region H in which at least a part of the flange and the sealant layer are heat-sealed (the shaded portion in FIG. 1 is the heat-sealing region H). ). “N” in FIG. 2 indicates the contents such as food.

3 to 6 are plan views showing an embodiment of the arrangement of the heat-sealed region and the heat-generating printing layer of the container with a lid for heating a microwave oven of the present invention. Further, FIG. 7 is a partially enlarged view of the vicinity of the region 26a having the heat generation printing layer of FIG.
In FIGS. 3 to 6, the outermost lid member 20 is shown by a solid line, and the constituent members located inside the lid member 20 are shown by a broken line.
In FIGS. 3 to 6, the region having the heat generation printing layer is indicated by reference numeral 26a. In the container with a lid for heating the microwave oven of FIGS. 3 to 6, a region (region 1) connecting the heat-generating printing layer from a part of the outer peripheral edge 12b of the flange in the circumferential direction to a part of the inner peripheral edge 12a of the flange in the circumferential direction. ), And a region (region 2) that is continuous from the region 1 and is inside the inner peripheral edge 12a of the flange. Further, the container 100 with a lid for heating the microwave oven of FIGS. 4 to 5 has a heat-generating printing layer in a region (region 3) continuous from the region 1 and outside the outer peripheral edge 12b of the flange. There is. In FIG. 7, the region 1 is indicated by reference numeral i, the region 2 is indicated by reference numeral ii, and the region 3 is indicated by reference numeral iii.

《Container body》
The container body has a flange at the opening and is made of paper. Paper contains water, which absorbs microwaves from microwave ovens. Cellulose, which is a raw material for paper, also easily absorbs microwaves.
In the packaging container in which the lid material is heat-sealed in the opening of the paper container body, the present inventors absorb microwaves when the microwave oven is heated, and the heat-generating printing layer is arranged in the heat-sealing area. Since the amount of microwaves absorbed by the heat-generating printing layer is reduced, it has been found that the sealing film may not be peeled off at the portion where the heat-generating printing layer is provided simply by forming the heat-generating printing layer. In addition, the present inventors have found that the above-mentioned tendency becomes more remarkable in the tableless microwave oven, which has been increasing in recent years.
In the present invention, by configuring the heat-generating printing layer to be provided in the area 1 and the area 2, even if the container body is made of paper, the lid material can be partially peeled off to increase the certainty of steaming. it can. The technical significance of Region 1 and Region 2 will be described later.

The type of paper that constitutes the container body 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.

The member constituting the container body preferably has 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 polyolefin 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 30 μm, and the thickness of the resin layer on the inner layer side of the paper is preferably 25 to 60 μm.

Further, the member constituting the container body may be made by sticking a plastic film on paper for the purpose of enhancing 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.
As the plastic film contained in the container body, the same plastic film as that exemplified in the base material layer of the lid material described later can be used.

The container body 10 is provided with an opening 11 on the upper surface. Further, the container body 10 is provided with a flange 12 on the outer peripheral edge of the opening 11.
The shape of the container body 10 may be any shape as long as it has the above-mentioned shape, and the shape beyond that is not limited. For example, the container body of FIGS. 1 and 2 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 FIGS. 1 and 2 has a larger opening than the bottom portion, the sizes of the bottom portion and the opening portion may be substantially the same, and the opening portion is smaller than the bottom portion. You may. From the viewpoint of making it easier to exert the effect of the present invention, it is preferable that the container body has a larger opening than the bottom portion. Further, although the container body of FIGS. 1 to 2 has a flat bottom, the container body may have legs. Further, although the flange of the container body shown in FIGS. 1 and 2 is flat, the shape of the flange may be annular.
The container body 10 can be manufactured, for example, by appropriately processing and adhering the paper forming the body 16 and the paper forming the bottom 17. The flange 12 can be formed, for example, by bending the paper forming the body portion 16.

The depth of the container body 10 is not particularly limited, but is about 40 to 110 mm, preferably 50 to 110 mm.

Further, from the viewpoint of enhancing the heat insulating property, the container body is preferably configured to have an air layer at least partially. For example, a container having a basic shape having a body and a bottom is prepared, and paper is wrapped around the body of the container so that an air layer is interposed. As a means for interposing an air layer between the body portion and the outer paper, for example, a means for partially forming a convex portion on the body portion can be mentioned.

The width of the flange 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 peeled and vaporized to maintain the internal pressure. Can be easily escaped. However, if the flange has a protrusion, it is necessary to change the shape of the seal head, it is difficult for a paper container to form a protrusion on the flange, and the packaging container of the present invention has a protrusion on a part of the flange. It is preferable that the flange does not have a protruding portion, considering that the lid material can be partially peeled and ventilated even if the flange material is not provided.

Specific examples of the layer structure of the members constituting the container body include the following (A1) to (A10). In addition, "/" indicates the interface of each layer. Further, in the following (A1) to (A10), the left side indicates the outer layer side, and the right side indicates the inner layer side (content side).
(A1) Paper / Resin layer (A2) Resin layer / Paper / Resin layer (A3) Paper / Resin layer / Plastic film / Resin layer (A4) Resin layer / Paper / Resin layer / Plastic film / Resin layer (A5) Paper / Adhesive layer / Vapor-deposited plastic film / Resin layer (A6) Paper / Air layer / Paper / Resin layer (A7) Paper / Air layer / Resin layer / Paper / Resin layer (A8) Paper / Air layer / Paper / Resin layer / Plastic film / Resin layer (A9) Paper / Air layer / Resin layer / Paper / Resin layer / Plastic film / Resin layer (A10) Paper / Air layer / Paper / Adhesive layer / Vapor-deposited plastic film / Resin layer

The above (A1) to (A10) can be used for both the body and the bottom. In the above (A2) and (A4), the resin layer on the outer layer side of the paper is foamed, and the above (A6) to (A10) are excellent in heat insulating properties, and therefore, the members constituting the body of the container body. Can be suitably used as.

《Lid material》
The lid material is configured to have a base material layer and a sealant layer, and also have a heat-generating printing layer on a part between the base material layer and the sealant layer or a part of the base material layer on the side opposite to the sealant layer. Will be done.
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).

8 to 9 are cross-sectional views showing an embodiment of the lid material 20.
The lid material 20 of FIGS. 8 to 9 has a base material layer 21 and a sealant layer 25, and has a heat generating printing layer 26 in a part between the base material layer 21 and the sealant layer 25. Further, the lid material 20 of FIGS. 8 to 9 has a pattern layer 23.

-Base layer-
The base material layer is preferably one or more selected from a plastic film and a paper base material.
The plastic film is preferable in that the gas barrier property is relatively good, and the paper base material is preferable in that the dead hold property (the property of being able to maintain a deformed state such as bending and twisting) is relatively good.
When the base material layer contains a paper base material, the paper base material absorbs microwaves from a microwave oven. Therefore, from the viewpoint of making it easier to exert the effect of the present invention, it is preferable that the base material layer does not contain a paper base material. On the other hand, from the viewpoint of facilitating the suppression of the formation of through holes in the lid material, the base material layer of the lid material preferably contains a paper base material. When a paper base material is used, it is preferable to form a heat-generating printing layer on the outer layer side of the paper base material from the viewpoint of microwave absorption efficiency.

The base material layer 21 may be a single layer as shown in FIGS. 8 to 9, 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. Since nylon has excellent piercing strength, it is preferable because it is easy to prevent the lid material from being torn when filling solid contents or when stacking containers.
Further, when at least one of a polyester film and a polyamide film having excellent heat resistance is used as the base material layer, a plastic film having insufficient heat resistance by itself can be used in combination. For example, by using at least one of a polyester film and a polyamide film together with a plastic film having excellent gas barrier properties such as an ethylene-vinyl alcohol copolymer resin film and a polyvinylidene chloride film, the heat resistance and gas barrier properties of the entire laminate can be obtained. Can be improved.

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, it is possible to easily improve the visibility of the pattern when the pattern layer is formed on the inner layer side of the plastic film.

-Sealant layer-
The sealant layer 25 has a role of sealing the opening of the container body by forming a heat seal region H in close contact with at least a part of the flange 12 by being partially heated by a seal head or the like.
The sealant layer 25 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 form a heat seal region in close contact with at least a part of the flange. 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.
Examples of the mechanism for imparting the easy peeling property include an interface peeling mechanism, an delamination mechanism, and a cohesive peeling mechanism, and any mechanism can be adopted. Hereinafter, the coagulation / peeling mechanism, which is an example of the mechanism, will be mainly described in the present specification.
The peeling principle in the coagulation peeling mechanism utilizes the fact that the cohesive force of the incompatible or partially compatible layer is small, and when the seal is opened, it is not the interface between the seal layer and the adherend (flange of the container body) but the non-phase. It is considered that this is due to the cohesive failure of the seal layer of the dissolved system or the partially compatible system.

Examples of the combination of materials having a coagulation fracture mechanism include a combination of polyolefin and polystyrene, a combination of polyethylene and polypropylene, a combination of low-density polyethylene and polybutene-1, and the like. Among these, a combination of low-density polyethylene and polybutene-1 is preferable.

In the combination of low-density polyethylene and polybutene-1, the mass ratio of low-density polyethylene and polybutene-1 is preferably 55:45 to 80:20, preferably 55:45 to 75:25. More preferred. By setting the mass ratio within the above range, it is possible to easily improve the easy peeling property.
The low-density polyethylene is preferably a high-pressure low-density polyethylene having a melting point of 110 ° C. or lower. The low density polyethylene preferably has an MFR of 0.5 to 50.
Further, polybutene-1 is preferably a homopolymer having a melting point of 120 ° C. or higher. The polybutene-1 preferably has an MFR of 0.2 to 20.

(Core layer)
The core layer is preferably made of a thermoplastic resin.
Examples of the thermoplastic resin in the core layer include ethylene-acrylic acid copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene-acrylic acid-acrylic acid ester ternary copolymer resin, and ethylene-methacrylic acid-acrylic acid ester. Three-way copolymer resin, ethylene-acrylic acid-methacrylic acid ester ternary copolymer resin, ethylene-methacrylic acid-methacrylic acid ester ternary copolymer resin, ethylene-acrylic acid ester-acid anhydride (maleic anhydride) Etc.) One or more selected from a ternary copolymer resin, an ethylene-methacrylic acid ester-acid anhydride (maleic anhydride, etc.) ternary copolymer resin and a low-density polyethylene can be mentioned.

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. For example, when the suppression of curl is emphasized, it is preferable that the thickness of the seal layer ≤ the thickness of the core layer. Further, from the viewpoint of suppressing the resin of the core layer from being exposed on the surface of the seal layer, it is preferable that the thickness of the core layer ≤ the thickness of the seal layer.
The thickness of the seal layer is preferably 5 to 50 μm, more preferably 5 to 30 μm, and even more preferably 5 to 15 μm.
The thickness of the core layer is preferably 5 to 50 μm, more preferably 7 to 40 μm, and even more preferably 10 to 30 μm.

The sealant layer can be formed, for example, by coextruding the seal layer and the core layer. Alternatively, it can be formed by melt-extruding a seal layer onto a film to be a core layer. It is preferable that the obtained sealant layer is not stretched in order to suppress shrinkage during heat sealing.

-Heat-generating print layer-
The heat-generating printing layer is formed on a part between the base material layer and the sealant layer or a part on the opposite side of the base material layer from the sealant layer.
From the viewpoint of effectively transferring heat to the sealant layer, the heat-generating printing layer is preferably formed in a part between the base material layer and the sealant layer.

The heat-generating printing layer is a layer that absorbs microwaves to generate heat, and includes a material that absorbs microwaves. Since the heat-generating printing layer is formed in a specific region in the container with a lid of the present invention, a part of the heat-sealing region of the container with a lid is peeled off by the heat generated in the heat-generating printing layer when heated in a microwave oven. It can be steamed. Such steaming may be referred to as "automatic steaming".
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, a light stabilizer such as a filler, a stabilizer, a plasticizer, an antioxidant, an ultraviolet absorber, a dispersant, a thickener, a desiccant, a lubricant and a cross-linking agent. Any additive such as, etc. can be added.

The container with a lid of the present invention needs to have a heat-generating printing layer in the following areas 1 and 2 when the container with a lid is viewed in a plan view.
<Area 1>
A region connecting a part of the outer peripheral edge of the flange in the circumferential direction to a part of the inner peripheral edge of the flange in the circumferential direction.
<Area 2>
A region continuous from the region 1 and inside the inner peripheral edge of the flange.

Having a heat-generating printing layer in the region 1 crosses the flange even when the inner peripheral edge H1 and / or the outer peripheral edge H2 of the heat-sealed region does not reach the inner peripheral edge 12a and / or the outer peripheral edge 12b of the flange. This means that it has a heat-generating printing layer.
Usually, in order to peel and steam the container with a lid by the heat generation printing layer, it is considered that the heat generation printing layer needs to be formed only in the region corresponding to the heat seal region of the portion to be peeled and steamed. However, as described above, the paper container body absorbs the microwaves of the microwave oven, and the microwaves absorbed by the heat-generating printing layer arranged in the heat-sealed area are reduced, so that only the area corresponding to the heat-sealed area is used. When the heat-generating printing layer was formed, the lid material may not be peeled off at the portion having the heat-generating printing layer. The present inventors have studied diligently, and the vicinity of the outer peripheral edge of the flange of the paper container body absorbs relatively little microwaves. By forming a heat-generating printing layer on the outer peripheral edge of the flange, the microwave of the heat-generating printing layer is formed. It was found that the absorption efficiency of fever can be increased.
Further, the heat-generating printing layer located inside the outer peripheral edge of the flange absorbs a predetermined amount of microwaves even though it absorbs a predetermined amount of microwaves. However, when the area of the heat generation printing layer is small, a sufficient heat generation amount cannot be secured. Therefore, it is important to have a heat-generating printing layer in a region (region 1) connecting a part of the outer peripheral edge 12b of the flange in the circumferential direction to a part of the inner peripheral edge 12a of the flange in the circumferential direction (FIGS. 3 to 3). 7). In FIG. 7, the region i is region 1.
Further, since it is difficult to widen the flange width of the paper container body, it is difficult to secure the area of the heat generating printing layer only in the area 1. Therefore, it is important to have a heat-generating printing layer in the region 2. The region 2 is a region continuous from the region 1 and is a region inside the inner peripheral edge 12a of the flange. In FIG. 7, the region of ii is region 2. The area of the heat-generating printing layer can be secured by increasing the length of the heat-generating printing layer (the length in the circumferential direction of the flange), but in that case, the pressure inside the container body is released to the outside at once after peeling and steaming. It will not be possible to cook properly.
The region 2 needs to be continuous from the region 1. This is because if the area 1 and the area 2 are not continuous, the area of the heat generating print layer is not increased.
As described above, by having the heat-generating printing layer in the region 1 and the region 2, the area of the heat-generating printing layer can be increased, and the heat-generating printing layer is provided near the outer peripheral edge of the flange having high microwave absorption efficiency. Therefore, it is possible to easily raise the temperature of the heat-generating printing layer when heating in a microwave oven, and it is possible to increase the certainty that the lid material is partially peeled off and ventilated.

The width W2 of the heat-generating print layer in the region 2 is preferably 1 to 15 mm, more preferably 2 to 10 mm.
By setting W2 to 1 mm or more, it is possible to easily increase the certainty that the lid material is partially peeled off and steamed. Further, by setting W2 to 15 mm or less, it is possible to easily suppress the heat generation printing layer from becoming unnecessarily high temperature.
The width of the heat-generating print layer in the region 2 is the width shown in W2 of FIG.

The container with a lid of the present invention preferably has a heat-generating printing layer in the following region 3 when the container with a lid is viewed in a plan view.
<Area 3>
A region continuous from the region 1 and outside the outer peripheral edge of the flange.

The region outside the outer peripheral edge of the flange is hardly affected by the absorption of microwaves by the paper container body, and can absorb a large amount of microwaves. Therefore, by having the heat-generating printing layer in the region 3, it is possible to easily raise the temperature of the heat-generating printing layer when heating in a microwave oven, and it is easy to increase the certainty that the lid material is partially peeled off and steamed. can do. In FIG. 7, the area of iii is the area 3.

The heat-generating printing layer of the region 3 may be formed so as to reach the outer peripheral edge of the lid material as shown in FIG. 4, or is formed inside the outer peripheral edge of the lid material as shown in FIG. You may.
As shown in FIG. 4, by forming the heat-generating printing layer of the region 3 so as to reach the outer peripheral edge of the lid material, the microwave absorption efficiency is enhanced, and the lid material is partially peeled off to ensure steaming. It is possible to easily enhance the sex.
The heat-generating printing layer located in the region outside the outer peripheral edge of the flange can absorb a large amount of microwaves, but if an excessive heat-generating printing layer is present in the region, the amount of heat generated becomes excessive and the lid material In the vicinity of the end portion, the lid material may be deformed or a through hole may be formed. As shown in FIG. 5, the above-mentioned risk can be reduced by forming the heat-generating printing layer of the region 3 inside the outer peripheral edge of the lid material.

The width W3 of the heat-generating print layer in the region 3 is preferably 0.5 to 10 mm, more preferably 1 to 5 mm.
By setting W3 to 0.5 mm or more, it is possible to easily increase the certainty that the lid material is partially peeled off and steamed. Further, by setting W3 to 10 mm or less, it is possible to easily suppress the heat generation printing layer from becoming unnecessarily high temperature.
The width of the heat-generating print layer in the region 3 is the width shown in W3 of FIG.

Area 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 minimum amount of heat generated for the lid material to peel off. 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 minimum amount of heat generated for the lid material to peel off. 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, and to prevent the lid material from being deformed or having through holes in the lid material. It can be done easily.

The length of the heat-generating printing layer is preferably 5 to 60 mm, more preferably 10 to 40 mm. In the present specification, the “length of the heat-generating printing layer” means the length of the heat-generating printing layer in the circumferential direction of the flange.
By setting the length of the heat-generating printing layer to 5 mm or more, it is possible to facilitate the discharge of steam to the outside. Further, by setting the length of the heat-generating printing layer to 60 mm or less, it is possible to suppress excessive discharge of steam to the outside and to easily suppress the hindrance to cooking of the contents.

The shape of the heat-generating printing layer when the container with a lid is viewed in a plan view is not particularly limited, and may be substantially square or substantially rectangular as shown in FIGS. 3 to 5, or trapezoidal as shown in FIG. It may have a shape other than that. When the plan view shape is a trapezoid, either the inner side or the outer side may be long, but as shown in FIG. 6, a trapezoid with a long inner side is preferable.

When the length of the heat-generating printing layer on the outside is defined as L1 and the length of the heat-generating printing layer on the inside is defined as L2 when the container with a lid is viewed in a plan view, it is preferable that L1 ≠ L2. By setting L1 ≠ L2, the amount of steam released to the outside after steaming can be appropriately controlled.
When L1 ≠ L2, the relationship may be L1> L2, but the relationship L1 <L2 is preferable. Since the internal pressure inside the container is transmitted concentrically, the lid material can be more easily peeled off by satisfying the relationship of L1 <L2.
Further, it is more preferable that the heat-generating printing layer satisfying the relationship of L1 <L2 satisfies the relationship in which the length continuously decreases from the outside to the inside. The heat-generating print layer of FIG. 6 has a long inner side and satisfies the relationship. L1 / L2 is preferably 0.30 to 0.90, more preferably 0.50 to 0.80, and even more preferably 0.60 to 0.70.
L1 and L2 are preferably adjusted within the range of the above-mentioned heat generation printing layer length (5 to 60 mm).

It is preferable that D1 which is the extending direction from the outside to the inside of the heat generating printing layer when the container with the lid is viewed in a plan view and D2 which is the direction orthogonal to the tangent line of the inner peripheral edge of the flange are substantially parallel.
By making D1 and D2 substantially parallel, the lid material can be easily peeled and steamed. In addition, substantially parallel means that the angle formed by D1 and D2 is 5 degrees or less, preferably 3 degrees or less, more preferably 2 degrees or less, and further preferably 1 degree or less.
The stretching direction D1 of the heat-generating printing layer can be calculated as, for example, the direction connecting the midpoint of the line forming the outer edge of the heat-generating printing layer and the midpoint of the line forming the inner edge of the heat-generating printing layer.

The region having the heat-generating printing layer in the surface of the lid material is defined as the heat-generating region. Further, the central point of the lid material is defined as X, and the midpoint of the line forming the outer peripheral edge of the heat generating region is defined as Y. At this time, it is preferable that the lid material satisfies the following condition (1).
<Condition 1>
Resistance value of the heat-generating printing layer in the XY direction <Resistance value of the heat-generating printing layer in the direction orthogonal to the XY direction

The "XY direction in the plane of the lid material", which is the reference of the direction of the condition 1, means the ideal direction of peeling and steaming.
Condition 1 defines that the resistance value of the heat-generating printing layer in the XY direction is smaller than the resistance value of the heat-generating printing layer in the direction orthogonal to the XY direction. Although the detailed cause is unknown, by making the resistance value of the heat-generating printing layer in the XY direction smaller than the resistance value of the heat-generating printing layer in the direction orthogonal to the XY direction, peeling and vaporization can be facilitated.

The heat-generating printing layer can be formed by applying an ink for forming a heat-generating printing layer on the support while transporting a support such as a base material layer in the flow direction (MD direction) and drying the support. When the heat-generating printing layer forming ink is applied onto the support in this way, the conductive components contained in the ink are oriented in the flow direction (MD direction). Therefore, it is considered that the resistance value in the flow direction (MD direction) becomes low, while the resistance value in the width direction (TD direction) becomes high, and anisotropy of the resistance value occurs.
Therefore, a lid material satisfying condition 1 can be obtained by determining the shape of the pattern of the heat-generating ink layer and the punching direction in consideration of the orientation of the conductive component in the MD direction.

In this specification, the resistance value of the heat-generating printing layer is measured by the two-terminal method with a constant current (DC current 60A) and a distance between measurements of 5 mm. Examples of the measuring device include the trade name "KEW MATE MODEL 2000A" manufactured by Kyoritsu Electric Instruments Co., Ltd.
Further, in the present specification, various measurements such as resistance value shall be carried out in an atmosphere of a temperature of 23 ° C. ± 5 ° C. and a humidity of 40 to 65% unless otherwise specified. Further, before each measurement, the measurement sample shall be exposed to the atmosphere for 30 minutes or more.

The ratio of the resistance value of the heat-generating printing layer in the XY direction to the resistance value in the direction orthogonal to the XY direction of the heat-generating printing layer (resistance value in the XY direction of the heat-generating printing layer / resistance value in the direction orthogonal to the XY direction of the heat-generating printing layer) Is preferably 0.70 to 0.95, more preferably 0.80 to 0.93.

The resistance value of the heat-generating printing layer in the XY direction is preferably 1.5 kΩ or more and 100 kΩ or less, more preferably 1.7 kΩ or more and 50 kΩ or less, and further preferably 2.0 kΩ or more and 30 kΩ or less. It is even more preferable that it is 5 kΩ or more and 15 kΩ or less.
By setting the resistance value to 1.5 kΩ or more, it is possible to suppress excessive heat generation of the heat-generating printing layer and to easily suppress problems such as through-holes in the lid material. Further, by setting the resistance value to 100 kΩ or less, the heat-generating printing layer can generate heat appropriately and can be easily peeled and vaporized.

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.

The heat-generating printing layer can be formed, for example, by applying a heat-generating printing layer-forming ink containing a material constituting the heat-generating printing layer onto the base material layer or the intermediate base material layer and drying the ink.

-Pattern layer-
The lid material may have a pattern layer.
The position of the pattern layer is not particularly limited as long as it is on the outer layer side of the sealant layer, and 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 FIGS. 8 and 9, the pattern layer 23 is arranged on the inner layer side of the base material layer 21. In this case, the base material layer 21 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.
As shown in FIGS. 8 and 9, the pattern layer 23 may be formed on the entire surface of the lid material or may be partially formed.

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 lid material. 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 lid material 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 and drying a pattern layer forming ink containing a material constituting the pattern layer on the base material layer or the intermediate base material layer.

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.

-Gas barrier layer-
The lid material may have a gas barrier layer.
The position of the gas barrier layer is not particularly limited as long as it is on the outer layer side of the sealant layer, but it is preferably between the base material layer and the sealant layer.
The positional relationship between the heat generation printing layer and the gas barrier layer is not particularly limited.
When the pattern layer is provided, the positional relationship between the gas barrier layer and the pattern layer is not particularly limited, and any of them may be on the sealant layer side (inner layer side). When the gas barrier layer is formed on the outer layer side of the pattern layer, it is preferable to configure the gas barrier layer with a material having light transmission so that the pattern layer can be visually recognized.
The gas barrier layer can be formed, for example, in a base material layer, an intermediate base material layer described later, or the like.

The gas barrier layer plays a role of blocking the permeation of oxygen, water vapor and the like. Further, the gas barrier layer may also be provided with a light-shielding property that blocks the transmission of visible light, ultraviolet rays and the like. The gas barrier layer may be composed of only one layer or may be composed of a plurality of layers of two or more layers.

The gas barrier layer can be formed as a vapor deposition film or a coating film by a known method.
When the gas barrier layer is formed on the base material layer or the intermediate base material layer, the base material layer or the intermediate base material layer may be surface-treated in advance from the viewpoint of improving the adhesion. Examples of the surface treatment include corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas, nitrogen gas, etc., glow discharge treatment, oxidant treatment, application of an anchor coating agent, and the like.

The vapor deposition film, which is an example of the gas barrier layer, has silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), and potassium from the viewpoint of enabling the contents to be sufficiently heated by microwaves in a microwave oven. It is preferably formed from oxides of inorganic substances such as (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), and yttrium (Y). ..
Examples of the method for forming the vapor deposition film include physical vapor deposition (PVD) methods such as vacuum vapor deposition, sputtering, and ion plating, and chemical vapor deposition (CVD) such as plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition. Law etc. can be mentioned.

The film thickness of the vapor-deposited film varies depending on the film-forming material, the required gas barrier performance, and the like, but is usually preferably about 5 to 200 nm, more preferably 5 to 150 nm, and further preferably 10 to 100 nm. In the case of an inorganic oxide such as a silicon oxide or an aluminum oxide, it is preferably about 5 to 100 nm, more preferably 5 to 50 nm, and further preferably 10 to 30 nm.

As an example of the gas barrier coating film, which is an example of the gas barrier layer, for example, the general formula R ¹ _n M (OR ² ) _m (in the formula, R ¹ and R ² are organic groups having 1 to 8 carbon atoms, and M is a metal atom. There are at least one alkoxide represented by (n is an integer of 0 or more, m is an integer of 1 or more, and n + m is the atomic value of M), and a polyvinyl alcohol-based resin and / or ethylene-vinyl. An ink obtained by polycondensing the alcohol copolymer by the sol-gel method in the presence of a sol-gel method catalyst, acid, water and an organic solvent is applied, and the mixture is 0.05 at 50 to 300 ° C. It can be formed by heat treatment for about 60 minutes.
The coating method can be, for example, a roll coating such as a gravure roll coater, a spray coating, a spin coating, dipping, a brush, a bar coating, an applicator or the like. The dry film thickness of the coating film is preferably about 0.01 to 30 μm, more preferably 0.05 to 20 μm, and further preferably 0.1 to 10 μm after one or more coatings.
The gas barrier coating film is preferably formed on the surface of the vapor deposition film from the viewpoint of improving the gas barrier property.

-Intermediate substrate layer-
The intermediate base material layer is used as a base material for improving the strength and processability of the lid material, for the purpose of changing the texture of the lid material, and for forming another layer such as a gas barrier layer. It is a layer provided between the base material layer and the sealant layer as needed. Examples of the constituent material of the intermediate base material layer include a plastic film and a paper base material.
When the lid material has a heat-generating printing layer on the inner layer side of the plastic film, it is preferable to arrange the intermediate base material layer on the inner layer side of the heat-generating printing layer.

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.
When the intermediate base material layer contains a paper base material, the paper base material absorbs microwaves from the microwave oven. Therefore, from the viewpoint of making it easier to exert the effect of the present invention, it is preferable that the intermediate base material layer does not contain a paper base material.

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.

-Adhesive layer-
Each layer constituting the lid material may be laminated via an adhesive layer from the viewpoint of improving the bonding strength between the layers.
The thickness of each of the adhesive layers is preferably about 0.01 to 20 μm, more preferably 0.05 to 15 μm, and even more preferably 0.1 to 10 μm.

The adhesive layer can be formed, for example, by a method using a general-purpose dry laminating adhesive or a melt extrusion method.
Examples of the dry laminating adhesive include polyvinyl acetate adhesives, polyacrylic acid ester adhesives, cyanoacrylate adhesives, ethylene copolymer adhesives, cellulose adhesives, polyester adhesives, and polyamide adhesives. Adhesives, polyimide adhesives, amino resin adhesives such as urea resin and melamine resin, phenol resin adhesives, epoxy adhesives, polyurethane adhesives (for example, cured products of polyol and isocyanate), reactive type Examples thereof include (meth) acrylic acid-based adhesives, rubber-based adhesives made of chloroprene rubber, nitrile rubber, styrene-butadiene rubber, etc., silicone-based adhesives, alkali metal silicates, inorganic adhesives made of low-melting point glass, and the like.

-Layer structure of lid material-
An embodiment of the layer structure of the lid material is shown below. In the following (B1) to (B8), the layer on the left side is the outer layer side, and "/" indicates the boundary of each layer.
(B1) Plastic film / heat-generating printing layer / pattern layer / adhesive layer / intermediate plastic film / adhesive layer / sealant layer (B2) Plastic film / pattern layer / heat-generating printing layer / adhesive layer / intermediate plastic film / adhesive Layer / Sealant layer (B3) Plastic film / Gas barrier layer / Heat-generating printing layer / Picture layer / Adhesive layer / Intermediate plastic film / Adhesive layer / Sealant layer (B4) Plastic film / Heat-generating printing layer / Picture layer / Adhesive layer / Gas barrier layer / Intermediate plastic film / Adhesive layer / Sealant layer (B5) Plastic film / Heat-generating printing layer / Pattern layer / Intermediate plastic film / Adhesive layer / Sealant layer (B6) Design layer / Heat-generating printing layer / Paper substrate / Adhesive layer / Intermediate plastic film / Adhesive layer / Sealant layer (B7) Picture layer / Heat-generating printing layer / Paper substrate / Adhesive layer / Sealant layer (B8) Plastic film / Picture layer / Heat-generating printing layer / Adhesive Layer / 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.

The heat seal region is preferably formed continuously in a band shape or a linear shape so as to go around the flange once (FIGS. 1, 3 to 6).
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, as shown in FIGS. 3 to 6, 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 (distance between H1 and H2 in FIGS. 3 to 6) is preferably 10% to 100%, more preferably 20 to 80% of the width of the flange.

"Contents"
The contents to be stored in the container body are not particularly limited. When the content is a liquid, the liquid content absorbs the microwaves of the microwave oven, so that the lid material tends to be difficult to peel and steam even if it has a heat-generating printing layer. In the present invention, even if the content is liquid, the peeling and steaming of the lid material is not hindered. Therefore, when the content is a liquid, the effect of the present invention can be more easily exerted, which is preferable.

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 a container with a lid [Example 1]
<Making lid material>
After corona discharge treatment is applied to one surface of the base material layer (stretched PET film having a thickness of 12 μm), the pattern layer forming ink is gravure-printed and dried, and the picture layer having a dry film thickness of 1.5 μm is applied to the base material layer. Formed on the entire surface of.
Next, an ink containing a conductive polymer (manufactured by Tokyo Ink Co., Ltd., product number MW heating agent) was gravure-printed on a part of the pattern layer and dried to form a heat-generating printing layer having a thickness of 0.5 μm. The heat-generating printing layer was formed so as to be present in the region 1 and the region 2 but not in the region 3 when the container with the lid was viewed in a plan view (see FIG. 3).
Next, an intermediate base material layer (stretched Ny, thickness 15 μm) was bonded to the surface of the heat-generating ink layer by a dry laminating method using a polyurethane-based adhesive.
Next, an adhesive layer-forming ink containing a polyurethane-based adhesive was applied to the side of the intermediate base material layer opposite to the heat-generating ink layer, and dried to form an adhesive layer.
Next, a two-layer sealant layer was extruded and laminated on the adhesive layer at an extrusion temperature of 300 ° C. to form a sealant layer. Of the two sealant layers, the layer on the adhesive layer side is a layer made of an ethylene-methacrylic acid copolymer (melting point 98 ° C.) and having a thickness of 20 μm, and the layer far from the adhesive layer is a low-density polyethylene. It is a layer having a thickness of 10 μm composed of a mixture (melting point 105 ° C.) and polybutene-1 (melting point 125 ° C.) (mass ratio 65:35).
Next, the laminate obtained in the above step was cut to obtain a lid material (diameter 103 mm) used in Example 1.
The lid material used in Example 1 is a base material layer (stretched PET), a pattern layer, a heat-generating ink layer (Note: the heat-generating ink layer is a part of the surface), an adhesive layer, and an intermediate base material layer (note: the heat-generating ink layer is a part of the surface) from the outer layer side. It has a stretched Ny), an adhesive layer and a sealant layer.

<Making a container with a lid for heating in a microwave oven>
《Container body》
A paper container body having a flange at the opening was prepared.
The body of the container body is made of a member in which resin layers are formed on both sides of the paper (paper basis weight is 250 g / m ² , the thickness of the resin layer on the outer layer side is 15 μm, and the thickness of the resin layer on the inner layer side is 25 μm). The bottom of the container body is a member in which resin layers are formed on both sides of the paper (paper basis weight is 200 g / m ² , the thickness of the resin layer on the outer layer side is 15 μm, and the resin layer on the inner layer side is formed. It is formed from a thickness of 25 μm).
The flange of the container body was circular, the inner diameter of the flange was 90 mm, the outer diameter was 100 mm, and the depth of the main body was 95 mm.
《Adhesion between container body and lid material》
After storing 300 g of water as the content in the container body, the lid material of Example 1 was heat-sealed under the following conditions to obtain a container with a lid for heating the microwave oven of Example 1. As the heat sealer, a trace sealer manufactured by Shinwa Machinery Co., Ltd. was used. The width of the heat seal region (distance between H1 and H2 in FIG. 3) was set to 3 mm. In the container with a lid of Example 1, the length of the heat-generating printing layer was 20 mm, and the width W2 of the region 2 was 10 mm.
<< Heat Seal Condition of Example 1 >>
・ Temperature: 165 ℃
・ Time: 1.5 seconds ・ Pressure: 2.0 MPa (air cylinder type)

[Example 2]
When the container with a lid is viewed in a plan view, the lid material and the container with a lid are provided in the same manner as in Example 1 except that the heat-generating printing layer is formed in the regions 1, 2 and 3 so as to have the heat-generating printing layer. Obtained (see FIG. 5). In the container with a lid of Example 2, the length of the heat-generating printing layer was 20 mm, the width W2 of the region 2 was 10 mm, and the width W3 of the region 3 was 2 mm.

[Example 3]
<Making lid material>
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 (manufactured by Tokyo Ink Co., Ltd., product number MW heating agent) was used as a part of the pattern layer to form a heat-generating printing layer having a thickness of 0.5 μm. The heat-generating printing layer was formed so as to be present in the region 1 and the region 2 but not in the region 3 when the container with the lid was viewed in a plan view (see FIG. 3).
Next, an intermediate base material layer (stretched PET, thickness 15 μm) was bonded to the opposite side of the pattern layer of the base material layer while melt-extruding polyethylene. By this step, an adhesive layer (molten polyethylene) having a thickness of 13 μm and an intermediate base material layer (stretched PET, thickness 15 μm) were formed on the opposite side of the pattern layer of the base material layer.
Next, a laminate obtained by laminating the same adhesive layer and sealant layer as in Example 1 on the side of the intermediate base material layer opposite to the adhesive layer was obtained.
Next, the laminate obtained in the above step was cut to obtain a lid material (diameter 103 mm) used in Example 1.
The lid material used in Example 3 is a heat-generating ink layer (Note: the heat-generating ink layer is a part of the surface), a pattern layer, a base material layer ( ^{paper base material having a basis weight of 150 g / m 2} ), and adhesion from the outer layer side. It has an agent layer, an intermediate base material layer (stretched PET), an adhesive layer and a sealant layer.

<Making a container with a lid for heating in a microwave oven>
Then, in the same manner as in Example 1, a container with a lid for heating the microwave oven of Example 3 was obtained. In the container with a lid of Example 3, the length of the heat-generating printing layer was 20 mm, and the width W2 of the region 2 was 10 mm.

[Comparative Example 1]
When the container with a lid is viewed in a plan view, the heat-generating printing layer is formed in the region 1 while the heat-generating printing layer is not provided in the regions 2 and 3, except that the heat-generating printing layer is formed. In the same manner, a lid material and a container with a lid were obtained. In the container with a lid of Comparative Example 1, the length of the heat-generating printing layer was 20 mm.

[Comparative Example 2]
When the container with a lid is viewed in a plan view, the area 2 has a heat-generating printing layer, while the area 1 has a heat-generating printing layer only near the center in the width direction, and the area 3 does not have a heat-generating printing layer. A lid material and a container with a lid were obtained in the same manner as in Example 1 except that the heat-generating printing layer was formed (a heat-generating printing layer located between H2 and 12b was obtained from the area of the heat-generating printing layer in FIG. 3). The excluded area is the area of the heat-generating print layer of Comparative Example 2). In the container with a lid of Comparative Example 2, the length of the heat-generating printing layer was 20 mm, and the width W2 of the region 2 was 20 mm.
In Comparative Example 2, the heat-generating printing layer is formed only in a part of the region 1. Therefore, in Table 1, the area 1 of Comparative Example 2 is described as “None”.

2. Evaluation <Peeling and steaming of lid material>
Twenty-five evaluation samples were prepared, each of which was filled with 300 ml of water in a container with a lid of each Example and each Comparative Example. Each evaluation sample was heated in a tableless microwave oven having an output of 600 W for 120 seconds, and it was visually confirmed whether or not the lid material was partially peeled off and steamed, and the samples were ranked according to the following criteria.
A: The lid material of all samples is partially peeled off and steamed.
B: Of the 25 samples, even one that did not peel and vaporize.
C: Of the 25 samples, 5 or more were not exfoliated and vaporized.

From the results shown in Table 1, the container with a lid for heating a microwave oven of the present invention can increase the certainty that the lid material is partially peeled off and automatically steamed even when the container body is paper. Can be confirmed.
Comparing the times until peeling and steaming of Examples 1 to 3, Example 2 was the fastest, followed by Example 1 and then Example 3.

10 Container body 11 Opening 12 Flange 12a Inner peripheral edge of flange 12b Outer peripheral edge of flange 16 Body 17 Bottom H Heat-sealing area H1 Inner peripheral edge of heat-sealing area H2 Outer peripheral edge of heat-sealing area 20 Lid material 21 Base material layer 23 Picture Layer 25 Sealant layer 26 Heat-generating printing layer 26a Area with heat-generating printing layer 27 Holding part 100 Container with lid for heating microwave oven

Claims (5)

A container with a lid having a flange at the opening and provided with a paper container body for accommodating the contents and a lid material for sealing the container body.
The lid material has a base material layer and a sealant layer, and a heat-generating printing layer is provided on a part between the base material layer and the sealant layer or a part of the base material layer on the side opposite to the sealant layer. Have and
The container with a lid is sealed by a heat-sealed region in which at least a part of the flange and the sealant layer are heat-sealed.
A container with a lid for heating a microwave oven, which has the heat-generating printing layer in the following regions 1 and 2 when the container with a lid is viewed in a plan view.
<Area 1>
A region connecting a part of the outer peripheral edge of the flange in the circumferential direction to a part of the inner peripheral edge of the flange in the circumferential direction.
<Area 2>
A region continuous from the region 1 and inside the inner peripheral edge of the flange. The container with a lid for heating a microwave oven according to claim 1, wherein the heat-generating printing layer in the region 2 has a width of 1 to 15 mm. The microwave oven heating according to claim 1 or 2, wherein the lid material protrudes outward from the outer peripheral edge of the flange, and when the container with a lid is viewed in a plan view, the heat-generating printing layer is further provided in the following region 3. Container with lid for.
<Area 3>
A region continuous from the region 1 and outside the outer peripheral edge of the flange. The container with a lid for heating a microwave oven according to claim 3, wherein the heat-generating printing layer in the region 3 has a width of 0.5 to 10 mm. The claim that D1 which is the extending direction from the outside to the inside of the heat generating printing layer when the container with a lid is viewed in a plan view and D2 which is a direction orthogonal to the tangent line of the inner peripheral edge of the flange are substantially parallel. The container with a lid for heating a microwave oven according to any one of 1 to 4.

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