JPH0249985B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a sealed container that has excellent properties such as strength, water resistance, and sealability, and is easy to open, and is particularly applicable to foods, medicines, etc. contained in the container body. The object of the present invention is to provide a sealed container that can be easily and reliably sealed by high-frequency induction heating without adversely affecting the contents of the container.

[Conventional technology]

BACKGROUND ART Conventionally, it has been very common practice to form a container from a laminated material made of a suitable combination of plastic, paper, metal foil, etc., and to heat-seal the lid after storing the contents, such as food, in the container.

Normally, the heat sealing described above is performed by fusing a heat-sealable plastic layer at the contact surface between the upper edge of the container opening and the lid surface, but there is a trade-off between sealing performance and ease of opening the lid during use. Therefore, depending on the purpose, one or the other had to be sacrificed.

One of the present inventors previously proposed that, as a means to balance the sealability and unsealability of the conventional container, there is an adhesive barrier between the surface plastic layer of the opening flange of the container body and the underlying paper layer. We proposed a laminated structure with a layer of agent (see Utility Model Publication No. 61-21407).

[Problem to be solved by the invention]

The heat-sealing of the lid of the conventional hermetically sealed container is generally carried out by a hot platen pressure bonding method or a high-frequency dielectric heating method. In the hot platen pressure bonding method, the inner plastic layer is melted by heat transfer from the surface. Not only does this involve a lot of time loss, but there are also problems such as fusion of the plastic to the surface of the heating plate and an increase in the temperature of the contents. If the container is shielded, extra power is required, and the stored contents often generate heat and heat up, potentially causing deterioration. Therefore, many conditions must be considered, such as container design, selection of stored contents, and adjustment of heating means. I had to.

[Means to solve the problem]

In order to solve the problems of the conventional heat-sealing means, the present invention applies a high-frequency induction heating method as the heating means, thereby achieving the desired heat-sealing strength while preventing the contents from rising in temperature. We succeeded in obtaining a simple container.

That is, the present invention provides a thermoadhesive plastic layer;
A container body formed of a laminated sheet consisting of an aluminum foil layer, an adhesive layer, a paper layer, and a plastic layer, and a paper sheet that is thermally bonded to the upper edge of the opening of the container body.
The container body has a lid made of a plastic laminated sheet or a plastic sheet. The gist is a sealed container for high-frequency induction heating sealing, characterized in that an adhesive plastic layer forms the upper surface of the flange, and an adhesion inhibitor band layer is provided between the adhesive plastic layer and the aluminum foil layer below. In this case, the laminated sheet portion of the protruding flange with the adhesion inhibitor band layer interposed therein has a narrow annular ridge formed by extrusion upward over the entire circumference of the upper surface of the protruding flange. It is included as an embodiment.

The above container body is made by rolling the upper edge of the opening inwardly or outwardly, and compressing the rolled part so as to extend toward the outer circumference of the container to form a protruding flange. Since it is molded to form the upper surface of the flange, the heat-adhesive plastic layer becomes the inner wall surface or outer wall surface depending on the above-mentioned tightening direction on the peripheral wall of the container body, and forms the container body. The laminated sheet is pre-prepared in the laminated sheet manufacturing process so that the layer of adhesive inhibitor is interposed in a suitable position under the heat-adhesive plastic layer that forms the upper surface of the protruding flange according to the above-mentioned winding conditions. An adhesion inhibitor is applied by printing.

The adhesion inhibitor band layer is made to exist over all or more of the adhesive width of the lid on the top surface of the protruding flange, and is formed over the entire circumference of the protruding flange. When the annular protrusion has a narrow width, it is necessary that the annular protrusion be present at least on the lower surface of the annular protrusion.

(Function) The sealed container of the present invention accommodates the contents and is hermetically sealed in the following manner.

After the contents have been placed in the container body, the lid to be thermally bonded is placed in contact with the protruding flange of the opening of the container body or the annular ridge provided there, and a slight pressure is applied. In this state, a high-frequency alternating magnetic field is generated by a coil to which a high-frequency current is applied close to the upper surface, thereby causing particularly large eddy current heat generation in the aluminum foil portion protruding from the protruding flange or annular convex strip. The heat generated by the heated aluminum foil, together with the heat insulating properties of the underlying paper layer, rapidly raises the temperature of the protruding flange or the thermoadhesive plastic layer on the upper surface of its annular ridge, resulting in its fusion. The lid is tightly sealed.

Therefore, the magnetic field generation time is extremely short and sufficient heat sealing is achieved, and at this time the magnetic flux density is sparse in other parts and almost no heat is generated, so the temperature rise of the contained contents can be ignored. degree, and further heat-sealed by an adhesion inhibitor band layer interposed between the heat-adhesive plastic layer on the top surface of the protruding flange or the top surface of the annular protruding portion provided thereon and the aluminum foil layer on the bottom surface. The peeling of the lid occurs when the thermoadhesive plastic layer on the upper surface of the adhesion inhibitor band layer part, which is fused to the lid surface, peels off from the adhesion inhibitor band layer surface as the lid is pulled. The heat-adhesive plastic layer easily undergoes elongation breakage between the portion of the protruding flange or the upper surface of the protrusion provided thereon that is fused to the lid surface and the portions that are adhered to the aluminum foil surface on both sides. The lid is then separated from the container body with a portion of the thermoadhesive plastic layer in an area corresponding to the adhesion inhibitor band layer adhered to the lid surface.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway side view of a sealed container containing contents, and 10 is the container body;
11 is a peripheral wall, 19 is a bottom, and the upper edge of the opening of the peripheral wall 19 is provided with a protruding flange 12 which is rolled up inwardly and press-molded in the outer circumferential direction.

Reference numeral 20 denotes a lid, which is placed on the upper edge of the opening of the container body 10 after the contents are contained therein, and is used to seal the opening surface of the container body 10 by a high-frequency induction heating sealing method described later.

FIG. 2 is an enlarged side view of the upper opening edge of the container body 10 and the lid 20, and the peripheral wall 11 is made of polyethylene, modified poppropylene, polyvinyl chloride, etc. heat adhesive plastic layer 2, aluminum foil layer 3,
It is formed of a laminated sheet 1 in which an adhesive layer 4, a paper layer 5, and a plastic layer 6 are laminated and bonded in this order, and the upper edge of the peripheral wall 11 is directed toward the inside of the container so that the edge 8 is located inside. The inner rolled part is tightened, and the inner rolled part is pressed out in the outer circumferential direction of the container to form the protruding flange 12.

In a portion of the laminated sheet 1 corresponding to the upper surface of the protruding flange 12, an adhesion inhibitor band layer made of polyamide, polyurethane, nitrified cotton, silicone, etc. is provided between the surface thermoadhesive plastic layer 2 and the aluminum foil layer 3. 7 is applied in advance to the aluminum foil surface during the production of the laminated sheet so that it is formed in an area slightly exceeding the adhesive area of the lid 20.

The lid 20 has thermoplastic layers 21 and 23 on both sides of a paper layer 22, and the thermoplastic layer 23 on the lower surface has particularly good affinity with the thermoadhesive plastic layer 2 of the laminated sheet 1. This is desirable.

As mentioned above, the lid 20 is placed over the upper edge of the opening of the container body 1 containing the liquid or solid content M,
When a high-frequency alternating magnetic field is applied from the upper surface of a magnetically permeable material such as a hardened melamine resin plate while being lightly pressurized, the largest heat increase is caused by the induced eddy current in the portion of the aluminum foil layer 3 located within the protruding collar 12. Due to the heat insulating properties of the lower paper layer 5, the heat is not transferred downward, but is conducted to the upper heat-adhesive plastic layer 2, producing a temperature-rising fusion effect, and the protruding flange 1
2 upper surface and the lid 20 can be completely and quickly sealed.

The lid 20 thus hermetically sealed can be removed by grasping its edge and pulling upwards.
The heat-adhesive plastic layer 2 fused to the surface is peeled off from the surface of the adhesion inhibitor band layer 7, and by further pulling, the peeled heat-adhesive plastic layer 2 is removed.
An elongated wave break occurs between the aluminum foil layer 3 and the lid can be easily opened.

In addition, in the present invention, as shown in FIGS. 3 and 4, a narrow strip continuous to the portion of the laminated sheet 1 in which the adhesion inhibitor band layer 7 is interposed, extends over the entire circumference of the upper surface of the protruding flange 12 of the container body 10. The annular protruding strip 13 may be formed by compression, thereby reducing the adhesive area with the lid 20 and providing easy-opening performance.

The numbers given in FIGS. 3 and 4 refer to the same parts as explained in FIGS. 1 and 2.

Next, FIG. 5 shows a blank plate 14 for forming the peripheral wall 11 of the container body 10. The laminated sheet 1 is cut into a fan shape, and adhesive is applied to the area 12' where the protruding flange 12 will be formed by winding on the peripheral wall. inhibitor zone layer 7,
As shown in Figure 6, the thermoadhesive plastic layer 2
and the aluminum foil layer 3. 15 is an adhesive allowance for forming the peripheral wall.

FIG. 7 shows a modification of the protruding flange 12 provided on the upper edge of the opening of the container body 1, in which the upper edge of the peripheral wall 11 is bent inward of the container, and the folded overlapping edge is further extended outward of the container. The case is shown in which a protruding flange 12 is formed by extrusion, and is practical depending on the strength of the laminated sheet 1 and the usage conditions of the container.

Therefore, the protruding flange according to the present invention includes one having a folded overlapping edge as described above.

Note that the plastic layer 6 of the laminated sheet 1
may be made of the same plastic as the thermoadhesive plastic layer 2 or other thermosetting material, depending on the type of contents.
Thermoplastic plastics can be appropriately selected and used, and in obtaining the laminated sheet 1, it goes without saying that either a laminating method or a coating method can be adopted. Although lids are shown, they could also be flanged lids, or they could be clear plastic lids.

FIG. 8 shows a case in which a container main body is
Figure 3 shows the case of tightly sealing using the high-frequency induction heating sealing method.

In this case, although not shown, the annular protruding strip 13 shown in FIGS. 3 and 4 can be formed on the protruding flange 12 of the container body 10 to make the container easy to open.

Next, in the present invention, the container body 10
The protruding flange constituting the container may be a protruding flange 12 formed by wrapping the upper edge of the peripheral wall 11 of the container body 10 outward and press-forming it in the outer circumferential direction, as shown in FIG.

In this case, although not shown, the structure of the laminated sheet includes, from the outer surface of the peripheral wall of the container body, a heat-adhesive plastic layer, a paper layer, an adhesive layer, an aluminum foil layer,
Use a layer of heat-adhesive plastic laminated in this order.

In addition, in the above, the protruding collar 12 has the third
It is also possible to form an annular convex strip similar to that shown in FIGS. Then, an adhesion inhibitor band layer similar to that shown in FIGS. 5 and 6 above is formed.

Next, when the lid 20 is heat-sealed to the container body 10 by the high-frequency induction heating sealing method of the present invention, in order to give a higher magnetic flux density to the aforementioned protruding flange 12 or the annular ridge 13 formed thereon, If a highly permeable metal ring suitable for the protruding flange 12 or the annular convex strip 13 is placed on the top surface of the lid 20 and crimped by its weight, the heat sealing time can be shortened and power can be saved. It can also be planned.

[Effects of the Invention] As explained above, in the sealed container for high-frequency induction heating sealing of the present invention, due to the above-described structure, high-frequency induction heating on the protruding flange surface of the upper edge of the opening of the container body is effective on the lid adhesion surface due to the structure of the laminated sheet. acts on,
It can be easily and reliably sealed without causing any unnecessary temperature rise to the contents, and the interposition of an adhesion inhibitor layer within the flange makes it easy to open the lid, and the container itself has excellent strength, water resistance, and storage capacity. It is possible to improve not only the shape but also the decorative properties of the aluminum foil layer.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a side view with a partially cutaway cross section, FIG. 2 is an enlarged side view with a main part in a cutaway cross section, and FIG. 3 is a diagram showing another embodiment. FIG. 4 is a perspective view of the container body, FIG. 5 is a plan view of a blank plate on the peripheral wall of the container body, and FIG. Figure 5 is an enlarged sectional view taken along the line AA, Figure 7 is an enlarged sectional view of main parts in another embodiment, Figure 8 is a partially cutaway side view of an embodiment using a cover lid, and Figure 9 is a partially cutaway side view of the embodiment using a cover. FIG. 7 is a cutaway sectional view of main parts in another embodiment. DESCRIPTION OF SYMBOLS 1... Laminated sheet, 2... Heat-adhesive plastic layer, 3... Aluminum foil layer, 4... Adhesive layer, 5... Paper layer, 6... Plastic layer, 7...
Adhesion inhibitor band layer, 10... Container body, 11... Peripheral wall, 12... Protruding collar, 13... Annular convex strip, 19...
...bottom, 20...lid.

Claims (1)

[Claims] 1. A container body 1 formed of a laminated sheet 1 consisting of a heat-adhesive plastic layer 2, an aluminum foil layer 3, an adhesive layer 4, a paper layer 5, and a plastic layer 6.
0 and a lid 20 made of a paper/plastic laminated sheet or a plastic sheet that is thermally bonded to the upper edge of the opening of the container body 10.
The upper edge of the peripheral wall 11 has a protruding flange 12 that is formed by winding and is pushed out in the outer circumferential direction,
The protruding flange 12 is a high-frequency induction heating seal characterized in that the thermoadhesive plastic layer 2 forms the upper surface of the flange, and an adhesion inhibitor band layer 7 is provided between it and the aluminum foil layer 3 below. sealed container. 2. The laminate sheet 1 portion of the protruding flange 12 with the adhesion inhibitor band layer 7 interposed therein has a narrow annular protrusion 13 extruded upward over the entire circumference of the upper surface of the protruding flange 12. A sealed container for high frequency induction heating sealing according to claim 1.