JPH0577835A - Vessel with metallic cover, and vessel body - Google Patents

Abstract

PURPOSE:To increase the gas barrier property of a vessel body after retort treatment. CONSTITUTION:A vessel 10 with a metallic cover is provided with the vessel body 14 having a flange 15, and a metallic cover 11 having the periphery 12 fastening the flange 15. The shell 14a and the bottom 14b of the vessel body 14 are composed of a vessel-form blank having an EVOH layer and a heat- melting resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container with a metal lid, which comprises a plastic container body and a metal lid, and a container body.

[0002]

2. Description of the Related Art There are various types of metal containers, such as metal cans, which can be classified into three-piece cans and two-piece cans depending on the structure of the can body. The three-piece can is also called a tin solder can and has a structure in which the cylindrical body, the lid and the bottom are sealed by double winding. On the other hand, the two-piece can is also called a tin-punched can and has a structure in which the body and the bottom (container main body) are integrally molded and the lid is double-wound.

These metal cans are used as food packaging containers for various food canned foods, juices, soft drinks, jams, dried foods, etc., and are rigid containers having particularly excellent sealing and storage functions. However, the metal can has the following points to be improved. That is, there is a limit to weight reduction because it is a metal can.

When an impact is applied, once it is crushed, it has no restoring property and is deformed.

The energy cost for manufacturing the plastic container is higher than that of the plastic container.

When the display effect of the container exterior is metal, it cannot be changed freely, and the exterior means is only by printing.

It is impossible to make a transparent container in which the contents can be confirmed without opening the can.

In order to solve the above-mentioned drawbacks of the conventional metal can, a container with a metal lid has been considered in which a metal lid is attached to the container body of a plastic container.

When a metal lid is attached to a plastic container body, the peripheral edge of the metal lid is wound around the flange portion of the container body.

[0010]

By the way, generally, the container body described above has a gas barrier layer such as an ethylene / vinyl alcohol copolymer (EVOH) layer in order to enhance the storability of the contents. However, when sterilizing the metal lid with the metal lid after retorting with hot water etc.
The OH layer may absorb water and the gas barrier property of the container body may deteriorate.

The present invention has been made in consideration of the above points, and even if a container with a metal lid is subjected to a retort treatment, it is possible to reliably prevent deterioration of the gas barrier property of the container body. An object is to provide a main body and a container with a metal lid using the same.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a plastic container body having a flange portion at the upper end opening,
The body and the bottom of the container body are molded from a container-shaped blank formed by thermoforming a laminated sheet, and a heat-meltable resin injected on the surface of the blank, and the flange is formed by injecting the heat-meltable resin. The laminated sheet is molded and has an ethylene / vinyl alcohol copolymer layer and heat-meltable resin layers disposed on both sides of the ethylene / vinyl alcohol copolymer layer. When the distance from the center position of the layer to the outer surface of the container body is l ₁ and the distance from the center position of the ethylene / vinyl alcohol copolymer layer to the inner surface of the container body is l ₂ , l ₁ : l ₂ = 1: 9 to 3: 7, a container body, a container body, the container body, and a metal lid having a metal lid having a peripheral portion around which the flange portion of the container body is wound. It is a vessel.

[0013]

According to the present invention, the arrangement position of the ethylene / vinyl alcohol copolymer layer of the container body is set to l ₁ : l ₂ = 1: 9.
It is possible to improve the gas barrier property of the container body after the retort treatment by setting the ratio to be 3: 7.

[0014]

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

1 to 4 are views showing an embodiment of the present invention. First, an outline of the container body and the container with a metal lid will be described with reference to FIG. As shown in FIG. 3, the container body 1
4 is a body portion 14a and a bottom portion 14b having an upper opening,
The container main body 14 is made of plastic as a whole, and is composed of a flange portion 15 provided on the peripheral edge of the upper end opening of the body portion 14a and protruding outward in the radial direction.

The high temperature contents 19 are stored in the container body 14 having such a structure, and the peripheral edge portion 12 of the metal lid 11 is wound around the flange portion 15 so that the metal lid-equipped container 10 is provided.
Is obtained.

Of these, the metal lid 11 is made of aluminum, and its front and back surfaces are coated with a synthetic resin layer.

Next, the container body 14 will be described in detail with reference to FIG. As shown in FIG. 1, the body portion 14 a of the container body 14
The bottom portion 14b is formed from a container blank 21 formed by thermoforming a laminated sheet, and a thermofusible resin 25 injected on the inner surface of the container blank 21. Also the container body 1
The flange portion 15 of No. 4 is formed by the hot-melt resin 25 injected on the upper edge of the container blank 21.

As the laminated sheet 21 used for forming the container-shaped blank 21, a laminated sheet having a gas barrier property is used. As a layer structure of such a laminated sheet, for example, as shown in FIG. 2, polypropylene (PP)
31 / adhesive layer 32 / ethylene / vinyl alcohol copolymer (EVOH) 33 / adhesive layer 34 / polypropylene (P
P) 35 is considered. However, instead of this,
For example, a layer structure of polyethylene (PE) / adhesive layer / ethylene / vinyl alcohol copolymer (EVOH) / adhesive layer / polyethylene (PE) may be used.

As described above, the laminated sheet 21 has a structure in which a heat-melting resin layer such as polypropylene or polyethylene is arranged on both sides of the ethylene / vinyl alcohol copolymer layer functioning as a gas barrier layer.

On the other hand, examples of the hot-melt resin 25 include polypropylene and polyethylene.

The hot-melt resin 25 used for injection molding must be one that fuses with the injection surface constituting resin of the laminated sheet with which it comes into contact. Therefore, when the injection surface of the laminated sheet is polypropylene, polypropylene is selected, On the contrary, when polyethylene is selected as the hot-melt resin 25, the injection surface of the laminated sheet is polyethylene.

Next, with respect to the arrangement position of the EVOH layer, FIG.
Will be explained. As shown in FIG. 2, the distance l ₁ between the outer surface S ₁ of the container body 14 and the center position P of the EVOH layer 33 is defined as the distance l ₂ between the outer surface S ₂ of the container body 14 and the center position P of the FEVOH layer 33. If done, l ₁ : l ₂ = 1: 9
It is about 3: 7. Of these, it is preferable that l ₁ : l ₂ = 2: 8.

By determining the ratio of l ₁ and l _{2 in} this way, the gas barrier property of the container body 14 against oxygen gas and the like can be improved as compared with the case of l ₁ : l ₂ = 5: 5 as described later. Can be improved.

The container 10 with a metal lid (FIG. 3) constructed as described above is then subjected to retort treatment with hot water or the like to sterilize the contents 19.

Next, FIG. 4 shows the result of the gas barrier property test of the container body when the position of the EVOH layer of the container body, that is, the ratio of l ₁ and l ₂ was variously changed. In this experiment, the metal lid 1 is attached to the flange portion 15 of the container body 14.
The container 10 with a metal lid formed by winding the peripheral portion 12 of No. 1 was subjected to retort treatment with hot water, and then the cumulative amount of oxidized permeation of the container body 14 was measured. As shown in FIG. 4, when the ratio of l ₁ and l ₂ is 1: 9 to 3: 7, the cumulative oxygen transmission rate of the container body is small, and when l ₁ : l ₂ = 2: 8, the cumulative oxygen transmission rate is _1. It can be seen that the amount is the smallest.

The reason for this is considered as follows. That is, when the EVOH layer of the container body absorbs water by the retort treatment, the gas barrier property of the EVOH layer generally deteriorates. In this case, when l ₁ becomes small, the EVOH layer moves to the outer surface side of the container main body, so that the water content of the EVOH layer is easily discharged to the outside, and the gas barrier property of the EVOH layer is recovered by the water content discharge. However, when l ₁ becomes smaller and the EVOH layer moves to the outermost surface side, the EVOH absorbs water during the retort treatment and becomes cloudy, which is not desirable in appearance. In addition, since there is no protective layer (PP layer), pinholes are likely to open, which may cause problems during distribution.

Therefore, as described above, l ₁ : l ₂ = 1: 9
It is considered that the gas barrier property of the container body is improved in the case of ~ 3: 7.

[0029]

As described above, according to the present invention,
Since the gas barrier property of the container body after the retort treatment can be improved, the storability of the contents can be improved.

[Brief description of drawings]

[Figure 1] Side view of the plastic container body

FIG. 2 is an enlarged view of part A of FIG.

FIG. 3 is a side sectional view showing a container with a metal lid.

FIG. 4 is a diagram showing a result of a gas barrier property test of a container body.

[Explanation of symbols]

 10 Container with Metal Lid 11 Metal Lid 12 Peripheral Edge 14 Container Main Body 14a Body 14b Bottom 15 Flange 21 Container Blank 25 Thermofusible Resin 31 Thermofusible Resin Layer 33 Ethylene / Vinyl Alcohol Copolymer Layer 35 Thermofusible Resin layer

Claims (2)

[Claims] 1. A plastic container body having a flange portion at an upper end opening, and a container-shaped blank formed by thermoforming a laminated sheet at a body portion and a bottom portion of the container body, and a heat-melting property injected onto the blank surface. The flange portion is formed by injecting a hot-melt resin, and the laminated sheet is disposed on both sides of the ethylene / vinyl alcohol copolymer layer and the ethylene / vinyl alcohol copolymer layer. A heat-meltable resin layer, and the distance from the center position of the ethylene / vinyl alcohol copolymer layer to the outer surface of the container body is l ₁ ,
A container body, wherein l ₁ : l ₂ = 1: 9 to 3: 7 when the distance from the center position of the vinyl alcohol copolymer layer to the inner surface of the container body is l ₂ . 2. A container with a metal lid, comprising the container body according to claim 1 and a metal lid having a peripheral portion around which a flange portion of the container body is wound.