JPH0621847Y2 - Food container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a container for mainly retort foods, and more particularly to a food container comprising a composite sheet suitable for heating the food with its contents in a microwave oven. It is a thing.

[Problems to be Solved by Conventional Technology] Conventionally, as containers for various retort foods, there have been many molded containers made of a multi-layer laminate material in which a polypropylene resin is used as a base material and a resin having a good gas barrier property is laminated on the base material. It is used. For example, it is composed of a composite sheet of polypropylene / ethylene-vinyl acetate copolymer / polypropylene or polypropylene / vinylidene chloride / polypropylene.

However, the container based on the polypropylene-based resin described above has a slightly poor heat resistance, and there is a risk of softening and deformation during heating in a microwave oven, and there is a problem in its shape retention. Especially when the polypropylene-based resin that is the base material is a foam,
Although the heat insulating property is improved, the heat resistance is further decreased, which is not satisfactory for heating and cooking in a microwave oven.

In particular, in recent years, retort foods are often cooked and eaten in a microwave oven together with the containers that package them.
Therefore, as a container for this type of retort food, it has various characteristics such as heat resistance enough to withstand heating in a microwave oven, heat insulation that can be held by hand after heating, and gas barrier property for food preservation. Is required.

Therefore, in the present invention, as a container for this type of retort food that is cooked and eaten in a microwave oven, a polyester resin, which is known as a material having excellent heat resistance, is used as a foam sheet having heat resistance. The above problem is solved by combining the resin film with a resin film having excellent gas barrier properties.

However, in the case of the polyester resin foamed sheet, it is considered difficult to laminate another resin film layer having excellent gas barrier properties such as polyvinylidene chloride resin, and therefore it is practically simply laminated. It cannot be used for conversion.

The present invention has been made in view of the above, and a foamed sheet of a polyester resin can be laminated with a resin film having an excellent gas barrier property without the above problems to be combined, and a composite sheet by this combination is used as a material. By doing so, it is possible to have various characteristics such as heat resistance, heat insulation, and gas barrier properties,
In particular, the present invention provides a food container that can be suitably used as a container for retort food or the like that is eaten by heating in a microwave oven.

[Means for Solving the Problems] The food container of the present invention for solving the above problems is a resin film layer having excellent gas barrier properties, which is obtained by forming a heat-resistant resin or heat-resistant adhesive layer on a foam sheet of a polyester resin. A composite sheet obtained by stacking the above is used as a material, and the composite sheet is integrally molded.

Particularly preferably, a polyester resin foam sheet,
A composite sheet using a polyethylene terephthalate resin is integrally molded as a layer interposed between the resin film layer having excellent gas barrier properties.

[Function] In the food container of the present invention having the above-described structure, the composite sheet as a constituent material is a foam sheet of polyester resin, a gas barrier through a layer of heat resistant resin such as polyethylene terephthalate resin or a heat resistant adhesive. Since the resin film layer having excellent property is laminated, it can be easily and surely laminated as compared with the case where the resin film layer having gas barrier property is laminated directly on the foamed sheet, and the composite sheet has excellent integrity.

That is, a foamed sheet of a polyester resin as a base material and a heat resistant resin layer such as a polyethylene terephthalate resin of the same type are relatively easy to laminate and have good integration, and the adhesive resin is also a foamed sheet. Therefore, the gas barrier resin film layer can be laminated on the foamed sheet without any problem by interposing the heat resistant resin layer, especially the polyethylene terephthalate resin layer, which is a similar resin, or the heat resistant adhesive.

In addition, the food container of the present invention molded from the composite sheet having the above-mentioned laminated structure can have an excellent heat insulating property that can be held by hand even after being heated in the microwave because of the foamed sheet of the polyester resin as the base material.

In addition, the foam sheet of the base material itself is made of polyester resin with excellent heat resistance, and the heat resistant resin layer and adhesive layer are laminated on it, so the heat resistance of the entire container is good, especially heat resistance. When a polyethylene terephthalate resin layer with excellent properties is laminated, it can retain and maintain sufficient heat resistance as this kind of container, and also has good shape retention during heating, enabling high retort treatment. Moreover, there is no risk of deformation even by heating in a microwave oven.

Further, due to the presence of the resin film layer having excellent gas barrier properties, the container has excellent gas barrier properties and excellent long-term storage stability of foods.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings.

In the embodiment of FIGS. 1 and 2, (A) shows a food container according to the present invention, and (B) shows a lid sealed to the food container (A).

The food container (A) is a non-foamed polyester-based resin foam sheet (1) on one side, on one side, by means such as dry lamination or hot melt lamination, mainly unstretched or low stretched polyethylene terephthalate resin layer Through (2), a resin film layer with excellent gas barrier properties
The composite sheet (10) in which (3) is laminated is integrally molded. In particular, in the example of the figure, a polypropylene resin layer was further formed on the gas barrier resin film layer (3).
(4) is molded from a laminated composite sheet (10),
The polypropylene resin layer (4) is formed so as to form a container inner surface layer and an upper surface layer of the opening end portion (11) which serves as a sealing portion of the lid (B). And usually the open end (11)
A sheet-like lid (B) is joined to the upper surface and sealed.

The composite sheet (10) is, for example, a polyethylene terephthalate resin layer (2) and a gas barrier resin film layer (3).
And is laminated by means such as dry lamination or extrusion lamination, and on top of that, a polypropylene resin layer (4)
To form a laminated body, and the laminated body is laminated on a polyester resin foam sheet (1) serving as a base material.

As described above, the polyester resin foam sheet
Since the non-foamed polyethylene terephthalate resin layer (2), which is a resin similar to the foamed sheet (1), is interposed between the (1) and the gas barrier resin film layer (3), the foamed sheet ( The polyethylene terephthalate resin layer (2) and the polyethylene terephthalate resin layer (2) can be relatively easily laminated and integrated, and thus the gas barrier resin film layer (3) laminated on the polyethylene terephthalate resin layer (2) is also used as the resin layer (2 It can be laminated on the foamed sheet (1) without any problem.

As the composite sheet (10), it is also possible to laminate a resin film layer (3) having excellent gas barrier properties on both sides of a polyester resin foam sheet (1) in the same manner as described above, but in practical use. It is sufficient to have a structure in which one side of the foamed sheet (1) is laminated as described above.

Polyester resin foam sheet as the base material (1)
Is a crystalline polyethylene terephthalate resin, a polybutylene terephthalate resin or other polyester resin, which is a foamed sheet mainly formed by extruding and foaming into a sheet, and particularly a polyethylene terephthalate resin layer (2) and a dry laminate or hot Melt laminating and the like are easily possible. This foam sheet
The thickness of (1) is usually 0.5 to 7.0 mm, preferably 1.0 to 5.0 mm, although it depends on the expansion ratio and the like.

Examples of the gas barrier resin film layer (3) include polyvinylidene chloride resin (PVDC), ethylene-vinyl acetate copolymer, nylon resins, and other resins having excellent gas barrier properties.

Furthermore, the polyethylene terephthalate resin layer (2)
It is preferable to use a non-stretched or low-stretched resin film because it facilitates molding from the composite sheet (10).

And a food container (A) consisting of the above composite sheet (10)
The presence of the resin film layer (3) having an excellent gas barrier property makes the stored food excellent in long-term storability.

Moreover, since the foamed sheet (1) as the base material is made of a polyester resin having excellent heat resistance, and a non-foamed polyethylene terephthalate resin layer (2) having excellent heat resistance is laminated on this, this type of It has sufficient heat resistance as a container, enables high retort processing, and does not deform even when heated in a microwave oven,
Sufficient shape retention can be maintained.

The polyester resin foam sheet (1), which is the base material, has excellent heat insulation properties and can be held by hand immediately after heating in a microwave oven, which makes it easy to handle after heating. .

The composite sheet (10) of the container material is not limited to the one provided with the polypropylene resin layer (4) as described above, but the polypropylene resin layer may be omitted as shown in FIG. Instead of the resin layer,
It can also be carried out by providing another polyolefin resin such as polyethylene resin or another resin layer.

When a polyolefin resin layer such as a polypropylene resin layer (4) is provided on the gas barrier resin film layer (3) inside the container as in the embodiment of FIG. 1 and FIG. Sheet for lid after storing food due to heat sealability
The seal of (B) becomes easy. That is, for example, a sheet-like lid (B) made of a composite sheet obtained by laminating stretched nylon, polyamide, or the like on aluminum foil is provided with an opening end (11).
On the other hand, it is possible to easily perform a joint seal by the heat fusion means, and not only the easy peel seal but also a firm tight seal can be performed. In addition, it has excellent oil resistance on the inner surface of the container and can be used even when the content is oily food.

Furthermore, due to the steam resistance and water permeation resistance of the polypropylene resin layer (4) and the like, it is possible to satisfactorily protect the gas-barrier resin film layer (3) having water absorbability, and it is also excellent in water resistance.

The polyester resin foamed sheet (1) and the layer interposed between the gas barrier resin film layer (3) are not limited to those using the polyethylene terephthalate resin described above, other heat resistant resins, For example, it can be carried out by using a heat-resistant resin of the same system such as polybutylene terephthalate resin, or an adhesive resin, and in this case also, in the same manner as above, the foamed sheet (1) and the gas barrier resin film layer (3) It is possible to easily laminate with and to have required heat resistance.

[Effects of the Invention] As described above, according to the food container of the present invention, a foam sheet of a polyester resin is used as a base material, and a heat resistant resin layer or a heat resistant adhesive layer of polyethylene terephthalate resin, which is a similar resin, to the base material. By using a composite sheet with a gas barrier resin layer laminated through the material, heat resistance sufficient to withstand high retort treatment and heating in a microwave oven, heat insulation that can be held by hand after heating, and food preservation Has characteristics such as gas barrier property for
Moreover, it can be integrally molded from a sheet.

Therefore, it can be suitably used as a container for retort foods and the like, in particular, for cooking food of the contents together with the container by heating in a microwave oven.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view showing an embodiment of the present invention, and FIG.
The drawing is the same sectional view, and FIG. 3 is a partial sectional view showing another embodiment. (A) …… The food container of the present invention, (10) …… Composite sheet, (1)…
… Foamed sheet of polyester resin, (2) …… Polyethylene terephthalate resin layer, (3) …… Resin film layer with excellent gas barrier properties, (4) …… Polypropylene resin layer.

Claims (2)

[Scope of utility model registration request] 1. A composite sheet obtained by laminating a resin film layer having excellent gas barrier properties on a foamed sheet of polyester resin through a layer of heat resistant resin or heat resistant adhesive, and integrally molding the composite sheet. Food container. 2. A food container obtained by integrally molding a composite sheet obtained by laminating a resin film layer having an excellent gas barrier property on a foamed sheet of polyester resin with a polyethylene terephthalate resin layer interposed therebetween, and integrally molding the composite sheet.