JPH10297604A - Sealing method for sealing container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a completely sealed packaged body in which contents are filled with air by using a hot pack method. SOLUTION: This sealing method is for a sealing container comprising a cover member and a container main body in which contents of a high temperature of 80 deg.C or higher are filled with air. The bottom shape of the container main body is recessed with a bottom recess 4, and the thickness of a corner part 5 between a wall part and the bottom recess is made thinner than the wall part and the bottom recess and thus the corner part 5 is shaped easily deformed by heat. When contents are filled in the container main body, the bottom recess of the container main body is held by a holding device 12, the flange part of the container main body is sealed with a cover member B, and on or after the completion of the sealing, the holding device is removed. Even when the contents of a high temperature of 80 deg.C or higher are filled with air in the container main body, though its bottom recess is deformed along the corner part and becomes projected, neither the breakage of the sealed part or the swelling of the cover material occurs. With the lowering of the inside temperature of the sealed container, the projected bottom recess is deformed along the corner part and returns to the bottom recess in a roughly original shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for sealing a hermetically sealed container which is filled with a high-temperature content of 80.degree.

[0003]

2. Description of the Related Art With the diversification of lifestyles, cooked foods and gas-packaged foods filled in sealed containers have been widely used in ordinary households. In particular, with the spread of microwave ovens, plastic containers and packages that can be easily heated and cooked in a microwave oven at home have been spreading. In general, these sealed containers for microwave ovens are not fully filled with the contents but are packed with air in preparation for volume expansion and boiling of the contents during heating. In addition, since the sealed container in which the container body and the lid are sealed is required to be easily openable, the container is filled with the contents at a temperature of 80 ° C. or less, and the lid is heat-sealed and completely sealed. Sealed containers and packages sterilized by retort or boiled are generally employed and sold at room temperature or chilled distribution. However, these retort- and boil-sterilized contents require long-term sterilization at a high temperature, which impairs the fresh taste of the contents, making it almost impossible to supply true delicious contents and increasing productivity. Was bad.

As a method of solving these problems, a method of recently filling the container body (A) with the contents at a high temperature of 80 ° C. or higher and heat-sealing the lid material (B) in a quenched or air-containing state at normal temperature. (Hereinafter, referred to as a hot pack method), the development of a product which is completely sealed and circulated in a chilled manner, that is, a product in which the breeding temperature range of the fungus is shortened and the taste of the contents is not lost is being studied. However, in the case of the hot pack method, FIG.
As shown in FIG. 5, the gas contained in the container is heated by the heat of the contents to cause volume expansion, and the internal pressure of the sealed container increases due to the vapor pressure of the contents. There is a disadvantage that the seal portion (6) of the container body (A) and the lid member (B) is destroyed at the same time when the seal portion (6) of the flange (1) of the container body (A) is separated, and the seal is released. .

[0005]

SUMMARY OF THE INVENTION The present invention has been made by various studies to solve the problems of the conventional hot-pack type sealed container. The purpose of the present invention is to seal the sealed container by the hot-pack method. It provides a method.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for sealing a sealed container (C) comprising a container body (A) filled with a high-temperature content of 80 ° C. or higher and a lid (B). The bottom of the container body has a concave bottom (4) with a concave shape, and the corner (5) at the boundary between the wall (3) and the bottom concave (4) is thicker than the wall and the bottom concave. It has a shape that is thin and easily deformed by heat.When filling the container body with the contents, the bottom recess of the container body is supported by the holder, and the lid is sealed to the flange part of the container body, and the sealing is completed. A method for sealing a hermetically sealed container, comprising removing the holder at the same time as or after completion.

The container body (A) used in the present invention is obtained by molding a single layer or a multilayer sheet of two or more layers by a vacuum forming method, a pressure forming method, or a combination thereof. The innermost layers of the lid material (B) can be heat-sealed, and at least one of them is made of an easy-opening resin or a film layer having an easy-opening function. Examples of such a resin include polypropylene, low-density polyethylene, high-density polyethylene, linear polyethylene, ethylene-vinyl acetate copolymer, polystyrene, ethylene-methacrylic acid copolymer, and ethylene-methacrylic acid copolymer metal crosslinked product. Can be mentioned.

The material of the container body (A) is made of a single material of polypropylene, polyester or nylon or a material obtained by further laminating an innermost layer on a multilayer material of two or more layers, and for the purpose of further improving gas barrier properties. It is possible to laminate ethylene-vinyl acetate copolymer, vinylidene chloride, nylon and the like. Since the container body is formed into a sheet, a proper sheet thickness and rigidity are required in forming, and
It is necessary to have a rigidity such that the shape is not deformed even at a temperature of 0 ° C., and the corner of the container body must be easily deformed by heat.
１．２1.20 μm, preferably 0.30 to 0.90 μm. The Young's modulus of the material is 500 at 100 ° C.
〜１０10,000 kgf / cm ² , preferably 1,000 to 4,000
kgf / cm ² is adopted.

The lid (B) can be made of a general material, but may be made of stretched polyester, stretched nylon, stretched polypropylene, or a combination film of the container body (A) and a heat-sealable resin film. If a gas barrier property is required, lamination of aluminum foil, vinylidene chloride resin and saponified ethylene-vinyl acetate copolymer is possible.

As for the shape of the container body (A), the bottom portion (2) has an arc shape (FIG. 1) and a flat shape (FIG. 2) as shown in FIGS.
Alternatively, it has a bottom recess (4) having a rib (FIG. 3), and a corner (5) at the boundary between the wall (3) and the bottom recess (4) is a wall (3) or a bottom recess ( 4) It is necessary to have a shape that is easily deformed by heat and has a small thickness. In particular, the provision of the ribs (13) increases the rigidity of the bottom concave portion, so that the corner portion is more easily deformed, which is useful for the present invention. The effect is more improved when the rib is provided in a section near the corner of the bottom concave portion. The rib may be one or plural, and may be continuous or discontinuous. As the lid material, a film-shaped lid may be used, but a drop lid or a convex shaped lid may be used.

At the time of filling the contents (8), as shown in FIG.
1) Put it on the top, and inflate or fill the high-temperature contents (8) of 80 ° C. or more with the bottom recess (4) of the container body (A) supported by the holder (12). After the filling, the container body (A) is lifted and supported by the holder (12) at the bottom concave portion (2) of the container body (A), and the lid member (B) is placed on the flange portion (1) of the container body (A). Then, the holder (12) is lowered and the hot plate (10) is raised as shown in FIG. At this time, as shown in FIG. 8, the bottom recess (4) as shown in FIG. 8 is bordered by the softened corner (5) of the container body (A) which is weakest against heat due to the temperature of the contents (8) and the thermal expansion of the gas-containing (9). ) Is deformed into a convex shape (7), and the internal pressure in the sealed container is stabilized or slightly reduced, so that the heat sealed portion between the flange portion (1) of the container body (A) and the lid member (B) ( 6) A stable sealed container can be obtained without breaking. Further, since the gas part (9) is decompressed as the temperature of the content (8) decreases, the shape of the sealed container is convex (7) at the corner (5) of the container body (A) as shown in FIG. ) The shape is deformed into the shape of the bottom concave portion (4), and the shape becomes close to the shape of the original container body (A), so that a stable sealed container can be obtained.

Here, the shape of the bottom concave portion (4) of the container body (A) varies depending on the gas-containing volume and the temperature, but after calculating the vapor pressure of the contents and the volume expansion of the gas, about 1/2 of the volume is calculated. Is preferred. Further, an inert gas such as N ₂ gas, CO ₂ gas, or a mixed gas thereof may be used as the gas-containing gas (9) in order to prevent oxidation of the contents.
Further, in order to shorten the temperature range of the recent breeding of the contents, the lower the temperature of the gas-containing material is, the lower the room temperature, preferably the lower the temperature, the more preferably 10 ° C.

[0013]

EXAMPLE The Young's modulus at 100 ° C. is 1800 kgf / cm ² ,
Use a 0.70 mm thick polypropylene sheet with a diameter of 11
A container main body (internal volume 300 ml, concave volume 18 ml) having a shape shown in FIG. 1 having a size of 0 mm, a height of 40 mm, and a height of a bottom concave portion of 6 mm was obtained by a vacuum forming method. A stretched polyester (12μ) / stretched nylon (15μ) / polypropylene easy peel sealant film (60μ) was prepared as a lid material. Then, 240 ml of hot water at 95 ° C. was filled into the container body, and adjusted so as to have an air content of 20%. Example 1 Using the above container body, the bottom recess was supported by a holder having substantially the same shape as the shape of the recess, and hot water of 95 ° C. was filled so as to contain 20% air, and the lid was heated with a hot plate. At 190
The seal was completely sealed at a temperature of 2.5 ° C. and a pressure of 2.5 kgf / cm ² . When the hot plate was raised from the pedestal and the holder was lowered and removed at the same time, the bottom concave part of the container body was deformed along the corner part and became convex, but the seal part did not break and the lid material No expansion occurred. In addition, the temperature inside the sealed container decreases, and the convex bottom portion is deformed along the corner portion to become almost the original bottom concave shape, and the contents are completely air-filled and completely sealed. Was obtained. << Comparative Example 1 >> When the lid was heat-sealed after filling the container body with hot water, the bottom concave portion was deformed into a convex shape due to the heat and weight of the hot water, and the seal portion was broken at the moment the hot plate was separated from the receiving table. Then, air spouted from the container body. << Comparative Example 2 >> The bottom portion of the container main body including the corner portion was formed thick enough not to be deformed by heat. When a test similar to that of Comparative Example 1 was performed using this container main body, the lid material became slightly swelled, and the seal portion was destroyed at the moment the seal board was separated from the pedestal, and air was ejected from the inside of the container main body.

[0014]

According to the method for sealing a sealed container of the present invention, even if the container is filled with high-temperature contents of 80 ° C. or more, the concave portion at the bottom of the container body is deformed along the corner and becomes convex. The sealing part does not break and the lid material does not expand, the temperature inside the sealed container decreases and the convex bottom concave part is deformed along the corner part, almost the original bottom concave shape Thus, a completely sealed package in which the contents were air-filled was obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a container according to an embodiment used in the present invention.

FIG. 2 is a cross-sectional view showing a container according to another embodiment used in the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of a container having a rib used in the present invention.

FIG. 4 is a sectional view showing a conventional sealing method.

FIG. 5 is a sectional view showing a state after a conventional seal is released.

FIG. 6 is a sectional view showing the sealing method of the present invention.

FIG. 7 is a sectional view showing the state after the seal of the present invention is released.

FIG. 8 is a cross-sectional view of the sealed container immediately after sealing according to the present invention.

FIG. 9 is a cross-sectional view of the sealed hermetically sealed container after sealing according to the present invention.

[Explanation of symbols]

A: container, B: lid material, 1: flange portion, 2: bottom portion, 3: wall portion, 4: bottom concave portion, 5: corner portion,
6: Seal part, 7: Convex part, 8: Contents, 9: Gas-containing, 10: Heat seal hot plate, 11: Heat seal receiving stand, 12: Holder, 13: Rib

Claims (2)

[Claims] 1. A method for sealing a hermetically sealed container comprising a container body filled with a high-temperature content of 80 ° C. or more and containing a high-temperature content, and a lid material, wherein the bottom shape of the container body has a concave bottom. The corner at the boundary between the wall and the bottom recess has a shape that is thinner than the wall and the bottom recess and is easily deformed by heat, and the bottom recess of the container body is filled when the container body is filled with contents. Support with a holder, seal the lid material to the flange of the container body, at the same time or after the sealing is completed,
A method for sealing a hermetically sealed container, comprising removing the holder. 2. The method for sealing a hermetically sealed container according to claim 1, wherein a rib is provided in the bottom concave portion.