JP3097772B2 - Lid body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover excellent in storage stability, sealing property and easy opening property.

[0002]

2. Description of the Related Art Conventionally, a plastic gas barrier container has a gas barrier thermoplastic resin such as an ethylene vinyl alcohol copolymer (hereinafter abbreviated as EVOH) or a vinylidene chloride resin (hereinafter abbreviated as PVDC) or an aluminum foil as a barrier layer. Multilayer films combining other heat-sealable resins and protective layers have been widely used. However, with these film-shaped lids, if the contents contain liquid, the contents will spill out of the container when opened, and the contents must be removed from the container in order to eliminate air that promotes the deterioration of the contents. It is necessary to seal in an overflowed state, and since the contents are on the seal flange, there is a disadvantage that poor sealing is likely to occur.

[0003] In order to solve these drawbacks, a molded lid (hereinafter abbreviated as a drop lid) dropped into a container is used. However, a drop lid made of aluminum foil having excellent gas barrier properties has a drawback that a free shape along a container is difficult to form. On the other hand, although the plastic drop lid can take any shape, the sealing part is thicker than the film lid, so the sealing performance is inferior, and the overall thickness is thinner than the container body, so the gas barrier property is limited. Had.

If these problems are not solved, Japanese Patent Application Laid-Open No. Hei 2-2055
No. 51, Japanese Unexamined Patent Publication (Kokai) No. 2-191162, and the like, a dropping lid with excellent storage stability combining an injection-molded product and an aluminum foil has been proposed, but these are very expensive and generally used. However, it has a drawback that it is difficult to use it for applications and a drawback that the shape is limited.

[0005]

SUMMARY OF THE INVENTION In view of the current state of the prior art, the present inventors have made intensive efforts to obtain a better lid. I got the prospect that I could achieve it. An object of the present invention is to provide a lid which can remove oxygen inside the container and can be easily opened without impairing the freedom of the shape of the dropping lid, and has excellent storage stability and sealability.

[0006]

According to the present invention, a composite sheet having at least two layers is formed so as to have a concave portion serving as a hollow portion.
The hollow portion is replaced with at least an inert gas in the food or an oxygen absorbent is sealed, and in a lid sealed with a film having excellent gas barrier properties, at least the innermost part of the seal layer that seals with the container main body has an ultrasonic wave. An infinite number of minute recesses are formed by the treatment, and the peel strength X between the seal layer of the lid and the adjacent layer, the seal strength Y between the seal layer and the container body, the cutting strength Z of the seal layer at the minute recess, and the like. Is a relation of Z <X <Y.

In the construction of the lid used in the present invention, an arbitrary thermoplastic resin is used for the plastic drop lid. It may be a single layer or some combination. For example, polypropylene (hereinafter abbreviated as PP), polyethylene (hereinafter abbreviated as PE), ethylene vinyl acetate copolymer (hereinafter abbreviated as EVA), polystyrene (hereinafter abbreviated as PS), polycarbonate (hereinafter abbreviated as PC) , Polyethylene terephthalate (hereinafter abbreviated as PET), polybutylene terephthalate (hereinafter abbreviated as PBT) and the like are used. As a method for forming these into multiple layers, known lamination techniques such as coextrusion, coextrusion lamination, extrusion lamination and dry lamination are used. In addition, as a method for forming these films and multilayer films, generally, a vacuum forming method, a pressure forming method, and a vacuum pressure forming method are used. In some cases, injection molding may be used, and any plastic may be used. It is molded using a molding method.

According to the present invention, a multilayer film containing aluminum is provided with a thermoplastic resin film which can be welded to the outer layer resin of the above-mentioned drop lid molded article, an aluminum foil as a barrier layer, and a PET, nylon (hereinafter NY) as an outer layer. Abbreviated)
What provided PP as a protective layer is used. As a method for producing these multilayer films, known lamination techniques such as a coextrusion method, a coextrusion lamination method, an extrusion lamination method and a dry lamination method are used. In addition, as a method of welding the multilayer film containing the aluminum foil and the drop lid molded product, a known heat sealing method, ultrasonic sealing method, and high frequency sealing method are used.

In the present invention, as a method of replacing the gas in the dropping lid, carbon dioxide and nitrogen inert to food preservation are dropped and the inside air is removed by flushing the inside of the lid or by vacuum replacement. Welded. When the oxygen absorbent is dropped into the lid, no replacement is necessary. Also, attachments such as chopsticks and forks necessary for eating foods and secondary contents such as seasonings can be put in the drop lid when this welding is performed.

[0010]

The operation of the lid according to the present invention will be described with reference to the drawings. In the present invention, as shown in FIG. 3, the plastic drop lid 1 is formed so as to be along the side surface of the container body 3 into which the contents enter, and the air contained in the container body is physically formed by this shape. Be eliminated. Also, there is a slight gap between the drop lid 1 and the container body 3, which suppresses the overflow of the contents and seals the contents without adhering to the flange portion of the container body. Is obtained.

Further, according to the present invention, since the lid 4 formed at the molded portion of the lid 4 is double-sealed by the aluminum multilayer film 2, it is possible to maintain sufficient storage stability. This is because when the hollow portion 5 formed by sealing the drop lid 1 and the aluminum multilayer film 2 is not replaced with an inert gas, the air in the hollow portion affects the contents. Since the hollow portion 5 is replaced with an inert gas, there is no adverse effect on the storage of the contents. As shown in FIG. 4, when the oxygen absorbing agent 6 is sealed in the hollow portion 5, oxygen which adversely affects the food out of the air in the hollow portion is absorbed, and the same effect as in the case of gas replacement is obtained. In this case, an effect of absorbing a little oxygen remaining inside the container is also observed.

Next, the opening method used in the present invention will be described. As an easy-opening method used in the present invention, it is effective that the structure of the drop lid has at least two layers and the sealing layer A of the drop lid 4 with the container body as shown in FIGS. 1 and 2.
To form an infinite number of minute recesses C by ultrasonic treatment, the peel strength X between the seal layer A of the drop lid and the adjacent layer B, the seal strength Y between the seal layer A and the container body, and the innermost part of the drop lid. A drop lid is used so that the cutting strength Z of the seal layer A at the provided minute concave portion C serving as the opening end portion satisfies the relationship of Z <X <Y.

In this manner, as shown in FIG. 5, the lid can be easily opened from the cross section of the lid at the outer end of the flange portion, and the peeling of the lid is completed at the minute concave portion C, and the opening is completed. At this time, the container main body and the drop lid are tightly sealed with the seal strength Y, and the sealing performance is not affected at all. Further, as shown in FIG. 6, even if the minute concave portion is provided at two places of the initial opening portion and the opening end portion, the opening can be easily performed by the same action.

In the present invention, the above-described opening method is considered to be the most preferable. However, in sealing the drop lid with the container body, the resin of the drop lid sealing layer itself, which is a well-known technique, is used to seal the container body with the sealing layer. There is no problem even if a method of welding is used.

[0015]

EXAMPLE A lid having the structure shown in Table 1 was prepared. The material of the molded part was prepared by co-extrusion to individual thickness. A drop lid molded product was prepared by using these sheets by a vacuum molding method. The aluminum multilayer film was prepared by dry laminating individual materials. Table 1
The drop lid having a small concave portion used in the above was processed by ultrasonic processing. Further, as for the container body, those having the constitution shown in Table 1 were first formed into a sheet by co-extrusion, and the sheet was prepared by a vacuum forming method. As a comparative example, a drop lid container prepared in the same manner as in the example was used.

As an evaluation method, the sealing property was examined by applying pressure from above the lid after sealing to check for leakage of the contents. For the shelf life, create a curry sauce as a content, fill in the container body, seal it with the lid of the example, the reference example, sterilize it with retort, store it at room temperature for half a year, open it, make it edible, Were examined by examining the degree of change. The opening property was also determined by comparing the feeling of opening with several monitors. Table 2 shows the results.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

According to the present invention, when the lid according to the present invention is used as shown in the examples, the food inside the container is excellent in preservability because oxygen in the container can be removed without impairing the flexibility of the shape of the drop lid. A container can be provided. In addition, a food container with excellent sealing properties, stable sealing properties, and easy opening can be obtained. Further, the above-mentioned disadvantages of the prior art can be solved, and it is suitable as a lid of a plastic container having excellent storage stability.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lid according to the present invention.

FIGS. 2A and 2B are partially enlarged views showing a minute concave portion of the lid of FIG. 1, wherein FIG. 2A is a cross-sectional view and FIG. 2B is a bottom view.

FIG. 3 is a sectional view showing one embodiment of a container using the lid of the present invention.

FIG. 4 is a sectional view showing another embodiment of the container using the lid of the present invention.

FIG. 5 is a partial cross-sectional view showing a method for opening a container using the lid of the present invention.

FIG. 6 is a partial cross-sectional view (a) and an enlarged partial bottom view (b) of the lid of the present invention showing another example in which a minute concave portion is provided on the sealing surface with the container body.

Claims (1)

(57) [Claims] 1. A composite sheet having at least two layers is formed so as to have a concave portion serving as a hollow portion, and the hollow portion is replaced with at least an inert gas in a food or an oxygen absorbent is enclosed, so that a gas barrier property is obtained. In a lid sealed with an excellent film , at least the innermost seal layer that seals with the container body is formed with an infinite number of minute recesses by ultrasonic treatment, and the seal layer of the lid and its adjacent layer are formed. A lid having a relation of Z <X <Y with respect to a peel strength X between the layers, a seal strength Y between the seal layer and the container body, and a cutting strength Z of the seal layer at the minute concave portion.