JP5236172B2 - Adhesive label and hermetically sealed package including the label - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive label used when cooking contents using a microwave oven in a state where contents such as food are stored in a sealed package, and a sealed package including the label. By sticking so as to cover at least a predetermined region of the heat-bonding part of the body, a microwave opening generates heat when receiving microwaves during cooking with a microwave oven. The present invention relates to a pressure-sensitive adhesive label that generates heat by receiving microwaves that can be automatically formed to discharge steam to the outside and prevent the contents from being blown out and the deformation or rupture of the sealed package, and a sealed package having this label Is.

  There are commercially available sealed containers for heating microwave ovens that can be cooked in a microwave oven while containing contents such as food. When these microwave-heated sealed containers are cooked using a microwave oven, the internal pressure in the container increases, and the container is deformed or ruptured, so various measures have been made to prevent this. Yes. For example, 1) A hermetic packaging container is disclosed in which a cut piece or a small hole is provided in paper or a synthetic resin, and a cover piece coated with a hot melt adhesive on the back is attached to the opening of the package (for example, Patent Document 1). If the container disclosed in Patent Document 1 is used, the hot-melt adhesive is softened by heating, and the internal pressure of the container can open a cut or small hole in the lid piece to reduce the internal pressure, thereby preventing the container from bursting. It can be done. However, when a low melting point hot melt is used, the hot melt melted during cooking may come into contact with the contents, which is not preferable for safety and health.

  Further, for example, 2) a container is disclosed in which a thin part having a thinner thickness than other parts is provided in a part of the lid of the container, or a small hole closed with a thin film is provided in a part of the lid (for example, Patent Document 2). In the container disclosed in Patent Document 2, the thin part is destroyed by the internal pressure that is increased by cooking, and the internal pressure of the container is decreased. May be damaged, and is not preferable for safety and hygiene as in Patent Document 1.

As a solution to the above problem, the container is sealed by heat sealing, and a heat-bonding part of a specific shape protruding in the inner direction of the container is provided on the heat-seal band, resulting from the moisture of food produced by heating There is disclosed a sealed cooking container for heating and cooking that can automatically open the protruding heat-bonded portion due to an increase in internal pressure due to, for example, expansion of water vapor or air in the container, and prevent the container from bursting or deforming (for example, And Patent Document 3). The container disclosed in Patent Document 3 can release the increased internal pressure from the projecting heat-bonded portion that is opened by cooking with a microwave oven, and can prevent the contents from being blown out or the container bursting or deforming. There are
As a method for forming the protruding heat-bonded portion, it is necessary to adopt either a method of forming a heat plate to be heat-sealed and heat-bonding or forming a rib on the flange portion, and There is a rather complicated problem that it is necessary to make the flange part wider than the case where the flange part is not provided with the protruding thermal bonding part, and the thermal bonding part is automatically opened without forming the protruding thermal bonding part. However, there has been a demand for a technique that can release the rising internal pressure and prevent the contents from being blown out and the container from being ruptured or deformed.
Japanese Utility Model Publication No.59-31590 Japanese Utility Model Publication No. 51-37402 Japanese Patent Publication No. 08-25583

  Therefore, the present invention has been made in view of the above problems, and is preferable from the viewpoint of safety and hygiene, and without forming a specially shaped thermal bonding portion such as a protruding thermal bonding portion, the thermal bonding portion of the sealed package body A self-adhesive label that generates heat when it is exposed to microwaves that are partially open and release steam generated from the contents to prevent the contents from being blown out and deformation or rupture of the sealed package. And providing a sealed package using the label.

In order to achieve the above-mentioned object, the inventor of the present invention described in claim 1 separates from a single layer or multiple layers of a base layer that is used by being attached to a sealed package that is cooked in a microwave oven. A pressure-sensitive adhesive label in which a conductive heat generating layer that generates heat by irradiating microwaves is laminated on the entire surface of the base material layer by laminating a mold layer through a pressure-sensitive adhesive layer. By heating and cooking in a microwave oven in a state where the adhesive label is attached so as to cover a predetermined region of the heat-bonding portion of the sealed package, the conductive heating layer generates heat by receiving microwaves from the microwave oven. As a result, the part where the adhesive label is attached is heated and melted compared to other parts where the adhesive label is not attached among the thermally bonded parts of the sealed package, and the heat of the sealed package is heated by the internal pressure increased by heating the contents. Adhesive label stuck on the adhesive part Position is characterized in that to release the internal pressure and opened.

The adhesive label according to claim 2 is characterized in that, in the pressure-sensitive adhesive label according to claim 1, the surface resistivity of the conductive heating layer is 10Ω / □ or more and 10 ⁷ Ω / □ or less. There is .

The present invention according to claim 3 is the pressure-sensitive adhesive label according to any one of claims 1 and 2, wherein the area of the conductive heat generating layer is 100 mm ² or more .

According to a fourth aspect of the present invention, in the pressure-sensitive adhesive label according to any one of the first to third aspects, the conductive heat generating layer is the pressure-sensitive adhesive layer .

Further, in the present invention according to claim 5, in the pressure-sensitive adhesive label according to any one of claims 1 to 4, an indication that the steam escapes to the base material layer is visible from the base material layer side. It is formed by printing .

Moreover, the sealed package which can be cooked with a microwave oven in the sealed state of this invention of Claim 6 is attached with the adhesive label in any one of Claims 1-5. It is.

  According to the present invention, a part of the thermally bonded portion of the sealed package is automatically opened to release the steam generated from the contents to prevent the contents from being blown out and the sealed package from being deformed or ruptured. It is possible to provide an adhesive label that generates heat upon receiving microwaves and a sealed package using the label.

The present invention will be described in detail below with reference to the drawings.
FIG. 1 is a diagram showing a basic layer configuration of an adhesive label according to the present invention, and FIG. 2 is a band-like heat-bonding portion of a sealed package in which a lid is sealed with a band-like heat-bonding portion at a flange portion of a bottomed container body. 2 is a diagram showing the positional relationship between the adhesive label and the adhesive label affixed to the lid, in which 2 is the lid, 4 and 4 'are adhesive labels, 21 is a knob, 40 is a conductive heating layer, and 41 is a base material layer. , 42 indicates a pressure-sensitive adhesive layer, and 43 indicates a release layer.

  FIG. 1 is a diagram showing a basic layer structure of a pressure-sensitive adhesive label according to the present invention. A pressure-sensitive adhesive label 4 includes a base material layer 41 and a release layer 43 laminated via a pressure-sensitive adhesive layer 42 and printing. The conductive heat generating layer 40 formed by the above is provided between the base material layer 41 and the pressure-sensitive adhesive layer 42 or on the surface layer of the base material layer 41. Although not shown, when the base material layer 41 is composed of two or more layers, the conductive heat generating layer 40 may be provided between the layers. In this case, a known lamination method such as a dry lamination method in which the base material layer 41 is laminated using a urethane-based adhesive or the like, or a sandwich lamination method in which polyethylene is heated and extruded from a T-die extruder and laminated. Are stacked. In addition, as a formation position of the said electroconductive heat generating layer 40, it is desirable to avoid the surface layer of the said base material layer 41. FIG. The reason for this is that if the conductive heat generating layer 40 is exposed on the surface layer, the conductive heat generating layer 40 may be damaged, which may impair the heat generating function. This is because it is necessary to further provide a surface protective layer on the conductive heat generating layer, which increases the cost.

  Examples of the base material layer 41 of the pressure-sensitive adhesive label 4 include polypropylene, polyethylene terephthalate, polyamide, etc., in particular, a film stretched in these biaxial directions, paper such as fine paper and coated paper, synthetic paper, or these The laminate is suitable.

Examples of the pressure sensitive adhesive forming the pressure sensitive adhesive layer 42 include natural rubber, acrylic resin, ethylene-vinyl acetate copolymer, vinyl acetate-vinyl chloride copolymer, styrene-butadiene-styrene copolymer. Polymers such as rosin derivatives, terpene resins and other tackifiers and fillers and anti-aging agents can be used as the main component of synthetic resins such as styrene-isoprene-styrene copolymers. A solid content of about 15 to 25 g / m ² is appropriate. As a coating method, a known coating method such as a roll coating method or a heat-melt extrusion method may be appropriately used.

In addition, as the release layer 43, one of high-quality paper, kraft paper, glassine paper, parchment paper, coated paper, or the like is directly applied to the surface, or after sealing with a known sealing agent, or polyethylene Or after applying an easy adhesion treatment as typified by corona discharge treatment, if necessary, a known silicone resin is applied by a known coating method such as a gravure coating method or a roll coating method. In addition, if necessary, a release sheet that has been heated and cured after drying can be used, or a release sheet made of a stretched or unstretched synthetic resin sheet such as polyethylene, polypropylene, or polyester, or these For example, after applying an easy adhesion treatment as typified by a corona discharge treatment on one surface of the For example, a release sheet that is applied by a known application method such as a gravure coating method or a roll coating method, and is heated and then cured as necessary, or a synthetic resin sheet or silicone as described above Examples include a release sheet obtained by applying fine embossing to a release sheet coated with a resin. In addition, as an application quantity in the case of apply | coating a silicone resin, 0.1-1.0 g / m < ² > is suitable as solid content.

The conductive heat generating layer 40 is not particularly limited as long as it is a substance that generates heat upon receiving microwaves. However, in consideration of the fact that it can be easily formed into an ink layer. Carbon black, silver, aluminum, ITO (indium tin oxide), etc. are suitable. The surface resistivity is preferably 10 Ω / □ or more and 10 ⁷ Ω / □ or less. The reason for this is less than 10 [Omega / □ heating value is reduced to the microwave is reflected, it is because the 10 ⁷ Ω / □ ultra heating value resistor is too large is reduced. Further, the size of the conductive heat generating layer 40 is suitably larger than the width of the thermal bonding portion so as to cross the thermal bonding portion of the hermetic package in the width direction and has an area of 100 mm ² or more. The reason for this is that if the size of the conductive heat generating layer 40 is smaller than the width of the heat-bonding portion, the portion of the heat-bonding portion where the conductive heat-generating layer 40 does not exist is generated by the heat generation of the conductive heat-generating layer 40. When it is not melted by heating, it takes a long time to start internal cooking after it has been cooked in a microwave oven, or when the internal pressure escapes or when the internal pressure escapes There is a risk that the contents may blow out, and if the area of the conductive heat generating layer 40 is less than 100 mm ² , the amount of heat generated is insufficient, and the conductive heat generating layer 40 is provided. This is because the internal pressure escapes from other than the above, and the above-described problems may occur.

  The conductive heat generating layer 40 may be printed and formed as a solid pattern on the entire surface, and finally cut into a label having a required size, or may be used in a polygonal shape such as a rectangular shape, a trapezoidal shape, or a triangular shape. It can be used as a label that is printed or formed at regular intervals in the vertical and horizontal directions on a shape, circle, ellipse, fan shape, etc. is there.

  Next, if the typical structure of the adhesive label 4 is illustrated, 1) pattern printing layer / paper / conductive heating layer / pressure-sensitive adhesive layer / release layer, 2) biaxially stretched film / pattern printing layer / Conductive heat generation layer / pressure sensitive adhesive layer / release layer, 3) pattern printing layer / paper / conductive heat generation layer / urethane adhesive layer / biaxially stretched film / pressure sensitive adhesive layer / release layer, 4) Pattern printing layer / paper / urethane adhesive layer / conductive heating layer / biaxially stretched film / pressure sensitive adhesive layer / release layer 5) Biaxially stretched film / urethane adhesive layer / pattern printing layer / Conductive heat generating layer / biaxially stretched film / pressure sensitive adhesive layer / release layer, 6) biaxially stretched film / pattern printing layer / urethane adhesive layer / conductive heat generating layer / biaxially stretched film / pressure sensitive Adhesive layer / release layer, etc., but is not limited to this. In addition, the pattern printed layer shown in the said structure is a display etc. which show that it is a location where vapor | steam escapes.

  Next, the present invention will be described in more detail with reference to examples.

[Production of bottomed container body]
Injection of a polypropylene container with a longitudinal section of approximately inverted trapezoidal shape with an inner diameter of the flange (opening diameter) of 74 mm, an outer diameter of the flange of 90 mm, a height of 80 mm, and an outer diameter of the bottom of 50 mm It was produced by a molding method.

(Production of lid)
A 12 μm thick biaxially stretched polyethylene terephthalate film (hereinafter referred to as PET film), a 15 μm thick biaxially stretched nylon film, and a 50 μm thick easy peel sealant (manufactured by Tosero Co., Ltd .: CMPS022C) are sequentially dried. After laminating by the lamination method, a lid body 2 that was die-cut (punched) into a shape as shown in FIG. 2 having a diameter of about 92 mm having a protruding knob portion was produced.

[Preparation of release sheet for adhesive labels]
After extruding heat-melted polyethylene on one side of 79.1 g / m ² fine paper using a T-die extruder to form a 15 μm thick polyethylene layer, the entire surface of the polyethylene layer becomes 1 g / m ^2. A release sheet was prepared by applying, drying and curing the silicone resin as described above.

[Preparation of base material layer of adhesive label]
A conductive heating layer (resistance value: about 10 ⁴ Ω / □) is applied to the entire surface of one side of a 25 μm-thick PET film subjected to corona discharge treatment by gravure printing using the gravure printing inks shown in Table 1. After printing and forming, an adhesive label base material is prepared by laminating 79.1 g / m ² of high-quality paper on the surface of the conductive heat generating layer by a dry lamination method using a two-component curable urethane adhesive. did.

[Production of adhesive labels]
The pressure-sensitive adhesive label of the present invention is obtained by applying an acrylic pressure-sensitive adhesive to the PET film surface of the pressure-sensitive adhesive substrate prepared above so that the solid content is 20 g / m ² and bonding the release sheet prepared above. Was made.

  The polypropylene container produced above was filled with water (160 ml), and a sealed package body was produced in which the lid produced above was thermally bonded at a flange portion with a 3 mm wide belt-like heat bonding part (see FIG. 2). Thereafter, the adhesive label produced above is cut to produce a rectangular label (10 × 30 mm), and the rectangular adhesive label 4 ′ from which the release sheet has been peeled off is shown in FIG. Ten test samples of the present invention adhered so as to cover the predetermined region were prepared. In FIG. 2, a portion surrounded by a concentric circle made of a broken line is a flange portion of a polypropylene container, and a portion indicated by a halftone dot is a 3 mm wide belt-like heat bonding portion.

[Comparative Example 1]
A sealed package body as a comparative example in which the polypropylene container prepared above was filled with water (160 ml) and the lid body prepared above was thermally bonded at the flange portion with a 3 mm wide belt-shaped heat bonding portion (see FIG. 2). Ten pieces were produced.

  The sealed package of Example 1 and Comparative Example 1 prepared above was heated in a 600 W microwave oven for 10 pieces (20 in total) until steam escaped. 1) From heating until steam escaped Time (vaporization time), 2) Temperature of the adhesive label sticking part (sticking part temperature), 3) Temperature of the lid other than the adhesive label sticking part (peripheral part temperature), 4) State when the vapor escapes (Sensory evaluation) was evaluated and the results are summarized in Table 2.

  As can be seen from Table 2, all of the sealed packages with adhesive labels attached were able to release the vapor gently by peeling off the band-like heat-bonded part of the label attaching part. The unsealed sealed package made a popping sound and the lid body drowned and water splashed, causing the inside of the microwave oven to become dirty. The adhesive label of the present invention is used by adhering to the band-like heat-bonding part of the sealed package, so that the part where the adhesive label is attached is more conductive than the other part where the adhesive label is not attached. The heat generating layer generates heat and the heat bonding portion is heated and melted, and the heat bonding portion heated and melted by the internal pressure increased by heating the contents can be easily opened to release the internal pressure.

  The pressure-sensitive adhesive label of the present invention is not limited to the sealed package formed of the molded container and the lid shown in the embodiment, and is also applied to a sealed package sealed by thermal bonding, for example, a hard type or soft type blister pack. The shape of the container is not limited to a substantially cylindrical shape, and may be a substantially rectangular parallelepiped shape. Also, a pillow type, a three-side seal type, a four-side seal type, a standing pouch, etc. It can also be applied to packaging bags. In addition, as the usage of the pressure-sensitive adhesive label of the present invention, the pressure-sensitive adhesive label is distributed in a state of being attached to the sealed package, and the user (consumer) is pasted so as to cover a predetermined region of the heat-bonding portion at the time of use. It may be cooked in a microwave oven later, or may be distributed to users (consumers) in a state of being pasted (applied) so as to cover a predetermined region of the heat-bonding portion of the sealed package. It ’s good.

It is a figure which shows the basic layer structure of the adhesive label concerning this invention. It is a figure which shows the positional relationship of the adhesive label affixed on the strip | belt-shaped thermobonding part of the sealed package which sealed the lid | cover with the strip | belt-shaped thermobonding part in the flange part of a bottomed container main body, and a lid | cover.

Explanation of symbols

2 Lid 4, 4 'Adhesive label 21 Knob 40 Conductive heating layer 41 Base material layer 42 Pressure sensitive adhesive layer 43 Release layer

Claims (6)

By laminating a base layer consisting of a single layer or multiple layers and a release layer via a pressure-sensitive adhesive layer, and sticking it to a sealed package that is cooked in a microwave oven, and irradiating with microwaves A heat-generating conductive heat generating layer is a pressure-sensitive adhesive label formed on all surfaces of the base material layer by printing so that the pressure-sensitive adhesive label covers a predetermined region of the heat-bonding portion of the sealed package. By heating and cooking in a microwave oven in a state of being formed, the conductive heating layer generates heat by receiving microwaves from the microwave oven, so that the adhesive label is not attached to the other part of the heat-bonded portion of the sealed package. Compared to the part where the adhesive label is attached, the part where the adhesive label is attached is opened in the heat-bonded part of the sealed package due to the internal pressure increased by heating the contents, and the internal pressure is released. To sticky label. The pressure-sensitive adhesive label according to claim 1, wherein the surface resistivity of the conductive heat generating layer is 10 Ω / □ or more and 10 ⁷ Ω / □ or less. The pressure-sensitive adhesive label according to claim 1, wherein an area of the conductive heat generating layer is 100 mm ² or more. The pressure-sensitive adhesive label according to claim 1, wherein the conductive heat generating layer is the pressure-sensitive adhesive layer. The pressure-sensitive adhesive label according to any one of claims 1 to 4, wherein the adhesive label is formed by printing so that an indication that steam escapes to the base material layer is visible from the base material layer side. A sealed package that can be cooked in a microwave oven in a sealed state, wherein the pressure-sensitive adhesive label according to claim 1 is attached.

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