JP6773720B2 - Packaging container and sealing method for packaging container - Google Patents

Description

The present invention relates to a packaging container for sealing a container body for storing foods and the like by adhering a lid body by heat sealing and a method for sealing the packaging container.

Conventionally, for example, a container for packaging foods sold in a supermarket or a convenience store has adopted a container body in which a lid is adhered by a heat seal to close an opening. In general, a container body that uses a heat seal has a sealability that maintains the quality of the contents, an easy-to-open lid, and the design of the entire packaging container, and is highly convenient overall. In recent years, technological improvements have progressed.

For example, in Patent Document 1, as a known technique, the film-like lid is annularly formed in the circumferential direction of the flange and has an inner angle with respect to the upper surface of the flange so that the film-shaped lid is three-dimensionally adhered and has a sealing property. It discloses a seal reinforcement ridge with the same outer angle. However, in this configuration, since the force for peeling the lid is dispersed, there is a problem that the opening property is difficult.

Therefore, as a new invention, an arc-shaped seal reinforcing ridge having a larger inner angle than an outer angle with respect to the upper surface of the flange at equal intervals with respect to the circumferential direction of the flange is disclosed. According to this configuration, the lid can be adhered more strongly to the inside than to the outside of the seal reinforcing ridges, so that not only the sealing performance is expected to be improved, but also the gap (apex) between the adjacent seal reinforcing ridges can be formed. It is expected that the opening property will be improved because the force for peeling the lid can be concentrated in one place.

As a whole, Patent Document 1 presupposes that the seal reinforcing ridge protrudes from the upper surface of the flange in order to secure the adhesive force of the lid to the flange. That is, the sealing property is improved when the lid is bonded three-dimensionally along the ridges rather than being bonded to the flat surface portion of the flange in a planar manner. And, it is positioned as the above-mentioned new invention that contributes to the improvement of the opening property of the lid while maintaining such sealing property.

Japanese Unexamined Patent Publication No. 2006-193212

However, Patent Document 1 does not disclose the relationship between the height of the seal reinforcing ridge and the pressurization by the sealing machine when sealing the lid. Generally, in order to seal the lid body on the container body, the lid body and the flange are pressurized and welded from above the lid body with a heat-generating sealing machine. At this time, if the heights of the flanges are not uniform, there may be a portion that is not sufficiently pressurized or a portion that is not pressurized at all.

That is, in the new invention described in the same document, there is a height difference between the highest portion of each seal reinforcing ridge and the lowest portion corresponding to the gap (apex) between the seal reinforcing ridges. There may be a difference in the degree of pressurization depending on the machine. As a result, the sealing strength becomes uneven in some places, and the sealing property may be deteriorated. On the other hand, if the pressurization of the sealing machine is increased in order to eliminate the unevenness of the sealing strength, the lid and the flange may be damaged beyond the allowable range of the load capacity. Furthermore, even with the known techniques described in the same document, it is extremely difficult to make the height of the seal reinforcing ridge uniform due to molding errors, shape defects, or distortion of the material, and it is extremely slight. Height differences occur in places.

Further, in the new invention described in the same document, since the angle inside the seal reinforcing ridge is steep, it is difficult to pressurize sufficiently with a normal sealing machine, and the shape of the seal reinforcing ridge is used to secure the sealing strength. A high-precision sealing machine that can pressurize is required. Furthermore, since the seal reinforcement ridge is located in the center of the flange in the width direction, the seal reinforcement ridge is not easily deformed in the width direction. Therefore, a seal is attached to the entire seal reinforcement ridge with a normal sealing machine that pressurizes from directly above. It is difficult to attach.

In response to such problems in the prior art, the inventors usually allow a normal height difference occurring in the flange of the container body and pressurize from directly above to thermocompression-bond the lid and the flange of the container body. Even with a sealing machine, we have arrived at a technical concept that ensures the desired sealing strength.
Therefore, an object of the present invention is to provide a packaging container and a method for sealing the packaging container, which does not depend on the capacity of the sealing machine and utilizes the characteristics of the flange of the container body to adhere the lid to ensure the sealing property. There is.

That is, the present invention is a packaging container including a lid, a container body made of polyethylene terephthalate sealed by the lid and having a circular shape in a plan view, and the container body is formed in an arch shape. It is provided with a flange portion for sealing the lid body, and the flange portion has an inner end edge portion located inside the container body and a height outside the inner end edge portion and at the same height as the inner end edge portion. It has an outer edge portion located, an apex located at an equal distance from the inner end edge portion and the outer end edge portion, and an inclination angle on the inner end edge side and an inclination on the outer end edge side. The corners are equivalent, and the vertical distance from the virtual line connecting the inner end edge portion and the outer end edge portion to the apex is 0.2 mm to 0.4 mm .

In other words, the packaging container in the present invention includes a flange portion provided continuously from the entire circumference of the peripheral edge of the side wall portion of the container body sealed by the lid, and the flange portion is the side wall portion. The height of the inner edge of the flange corresponding to the peripheral edge of the portion, the seal portion arranged outside the inner edge of the flange for adhering the lid, and the inner edge of the flange. Moreover, it has a flange outer end edge portion arranged outside the seal portion, and the seal portion is upward all around the flange portion and from the flange inner end edge portion to the flange outer end edge portion. It is characterized in that it is formed in a curved arch shape.
The apex of the seal portion is located equidistant from the flange inner end edge portion and the flange outer end edge portion, and the apex of the seal portion is vertical to the flange inner end edge portion and the flange outer end edge portion. The distance in the direction is preferably 0.1 mm to 0.7 mm.

Further, the method for sealing a packaging container according to the present invention is a method for sealing a packaging container in which a lid is bonded with a sealing machine to seal the container body, from the entire circumference of the peripheral edge of the side wall portion of the container body. The continuously provided outer flanges are seals arranged outside the inner edge of the flange to bond the inner edge of the flange, which corresponds to the peripheral edge of the side wall, to the lid. It has a portion and a flange outer end edge portion that is at the same height as the flange inner end edge portion and is arranged outside the seal portion, and the seal portion is the entire circumference of the flange portion and the flange inner end. It is formed in an arch shape that curves upward from the edge portion to the outer edge portion of the flange, and the apex of the seal portion is equidistant from the inner edge portion of the flange and the outer edge portion of the flange. The seal portion is pressed from above the lid body with the seal machine until the height of the apex of the seal portion is equal to the height of the inner edge portion of the flange and the outer edge portion of the flange. It is characterized in that the seal portion is adhered to the lid body in a flat shape over the entire circumference of the flange portion.

In the method for sealing a packaging container and a packaging container according to the present invention, a normal sealing that allows a normal height difference occurring in the flange of the container body and pressurizes from directly above to heat-bond the lid and the flange of the container body. Even in the machine, the lid body can be adhered to ensure the sealing property by utilizing the characteristics of the flange of the container body.

It is a perspective view from the upper direction of the packaging container in one Embodiment of this invention. It is a partially enlarged end view of the packaging container in one embodiment of the present invention. It is a conceptual diagram which shows (a) immediately before thermocompression bonding, (b) at the time of thermocompression bonding, and (c) after thermocompression bonding of the sealing method of a packaging container in one Embodiment of this invention.

Hereinafter, the packaging container (hereinafter, also referred to as “the present packaging container”) and the sealing method of the present packaging container according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3.
In these figures, a plurality of identical parts may be numbered only for one part, and overlapping parts may be omitted. For convenience of explanation, a predetermined part and this leader line are indicated by a broken line or an imaginary line (two-dot chain line).

First, the structure of the main packaging container will be described.

The packaging container according to the embodiment of the present invention is a container body M having a square shape in a plan view in which food or the like is stored, and the opening portion of the container body M is heat-sealed to form a synthetic resin molded lid, film, or the like. It is closed by the lid of the. The heat seal is performed by pressurizing and heating the bonded portion between the container body M and the lid from the surface side of the lid with a predetermined sealing machine.
Although not shown, in the case of a molded lid, for example, it corresponds to the top surface of the lid, the side wall of the lid provided so as to extend downward from the entire circumference of the peripheral edge of the top, and the lower end of the side wall of the lid. It is provided with at least a lid flange portion provided so as to extend outward from the entire circumference of the peripheral edge.

FIG. 1 is a perspective view from above where the inside of the container body M can be seen. As shown in FIG. 1, the container main body M has a square main body bottom 1 in a plan view, a main body side wall 2 provided so as to extend upward from the entire peripheral edge of the main body bottom 1, and a main body side wall. It is provided with a main body flange portion 3 provided so as to continuously extend outward from the entire circumference of the upper end edge of the portion 2.

The main body flange portion 3 is a seal arranged outside the flange inner end edge portion 31 for adhering the lid to the flange inner end edge portion 31 corresponding to the peripheral edge of the main body upper side wall portion of the main body side wall portion 2. It has a portion 32 and a flange outer end edge portion 33 which is at the same height as the flange inner end edge portion 31 and is arranged outside the seal portion 32. The seal portion 32 is formed in an arch shape that is curved upward from the entire circumference of the main body flange portion 3 and the flange inner end edge portion 31 to the flange outer end edge portion 33. In other words, the main body flange portion 3 is formed in an arch shape, and the flange inner end edge portion 31 located inside the container main body M and the flange inner end edge portion 31 outside the flange inner end edge portion 31 and the flange inner end edge portion 31. It has a flange outer edge 33 located at the same height, a flange 32a shown in FIG. 2 equidistant from the flange inner edge 31 and the flange outer edge 33, and a seal portion. 32 bulges from the entire width direction of the main body flange portion 3.

According to this configuration, when the lid is sealed on the main body flange portion 3 of the container main body M, the seal portion 32 is evenly crushed from directly above by the minimum necessary pressure by the sealing machine, and covers the entire circumference. Since the height of the seal portion 32 becomes uniform, a gap is less likely to occur between the seal portion 32 and the lid. That is, the packaging container is not only less likely to be damaged by the pressurization of the sealing machine due to the cushioning effect of the sealing portion 32, but also the lid can be brought into close contact with the entire surface of the sealing portion 32, so that it is desired over the entire circumference. Seal strength can be provided. Therefore, this packaging container can prevent sudden opening of the lid and deterioration of the sealing property due to variations in the sealing strength of the lid.
Here, when the flange portion 3 has a flat shape, for example, when both ends of the sheet first touch the mold during molding, that portion is cooled and the sheet is hardened, both ends of the sheet protrude, and both ends of the sheet. The shape is dented (not shown). On the other hand, in the case of a shape in which the central portion of the flange portion 3 is projected, when the central portion of the sheet first touches the mold during molding, that portion is cooled and the sheet is hardened, and the flange portion 3 shown in FIG. It can be arched like this.

FIG. 2 is an enlarged end view of the periphery of the main body flange portion 3 when the container main body M is cut from the vertical direction. As shown in FIG. 2, the apex 32a of the seal portion 32 is located equidistant from the flange inner end edge portion 31 and the flange outer end edge portion 33, and the flange inner end edge portion 31 and the flange outer end edge portion are located from the apex 32a. The vertical distance d to 33 is 0.1 mm to 0.7 mm, preferably 0.2 mm to 0.4 mm. In other words, the vertical distance d from the virtual line connecting the inner end edge portion 31 of the flange and the outer end edge portion 33 of the flange to the apex 32a is 0.1 mm to 0.7 mm. If the distance d is smaller than 0.1 mm, it is difficult to form the seal portion 32 into an arch shape, and if it is larger than 0.7 mm, the seal portion 32 bulges too much with respect to the flange inner end edge portion 31 and the flange outer end edge portion 33. The seal strength will vary. It is preferable that the inclination angle α of the seal portion 32 on the flange inner edge portion 31 side and the inclination angle β on the flange outer end edge portion 33 side are the same. Since the inclination angle α on the inner end edge portion 31 side of the flange and the inclination angle β on the outer end edge portion 33 side of the flange are equivalent, the seal portion 32 can be molded in an arch shape and a desired seal strength can be obtained. it can.

The container body M may have a rectangular shape, a circular shape, a semicircular shape, or an elliptical shape in a plan view. The main body side wall portion 2 is continuously provided from the lower side wall portion (not numbered) of the main body provided continuously from the main body bottom portion 1 and continuously outward from the entire circumference of the upper end edge of the main body lower side wall portion to form a step. It may have a main body side wall surface portion (not numbered) formed and a main body upper side wall portion (not numbered) provided continuously from the entire peripheral edge of the main body side wall flat surface portion. The main body flange portion 3 may have a flange tip portion (not numbered) arranged so as to continuously extend outward and downward from the entire peripheral edge of the flange outer end edge portion 33. In the case of a molded lid, the shape may be the same as or different from that of the container body M in a plan view. The lid flange portion of the molded lid may be flat or curved as long as it can be heat-sealed with the main body flange portion 3.

Next, the components of the container body in the present packaging container will be described.

The container body is formed by, for example, adopting vacuum forming, hot plate compressed air forming, vacuum compressed air forming, and double-sided vacuum forming, and thermoforming a synthetic resin sheet. As the synthetic resin sheet, for example, a polyester resin such as polyethylene terephthalate, a styrene resin such as polystyrene, or an olefin resin such as polypropylene may be used, and a sheet composed of a single-layer or multi-layer laminate may be used. It contains a gas barrier layer typified by a vinyl alcohol copolymer, polyvinylidene chloride, and MX nylon (registered trademark). Additives such as fillers may be included. As the sheet, a non-foaming material is preferable. A synthetic resin laminated film may be laminated on the front surface or the back surface of the sheet, and a gas barrier layer or a printing layer may be laminated on the laminated film. As an example of the lid, such as a laminated film such as OPET layer / dry lami adhesive layer / Ny layer / EVOH layer / adhesive layer / PP layer, PP layer / adhesive layer / EVOH layer / adhesive layer / PP layer. Examples thereof include a polyolefin-based gas barrier laminated sheet, a laminated sheet of a gas barrier laminated film and a sheet such as a PP layer / adhesive layer / Ny layer / adhesive layer / EVOH layer / dry lami adhesive layer / APET layer. The thickness of the synthetic resin sheet is not particularly limited and may be 0.2 mm to 0.8 mm, preferably 0.25 mm to 0.6 mm. If it is smaller than 0.2 mm, there is a risk that the container body may be damaged due to an impact such as during transportation due to insufficient rigidity. If it is larger than 0.8 mm, the cost may increase due to the increase in the material thickness and the work efficiency may decrease.

According to the configuration including the gas barrier layer, it is expected that the storage period of food products can be extended by performing gas replacement packaging. Here, the gas barrier layer is not particularly limited as long as the permeability of a gas such as oxygen gas, water vapor gas, or carbon dioxide gas is low. Specifically, the oxygen permeability according to JIS K 7126 is 1000 ml with a thickness of 25 μm. ^{/ m 2 · 24hr · MPa (} RH 75% at 20 ° C.) may be a less resin, such as ethylene - vinyl alcohol copolymer (EVOH), or may be a polyamide -6 (PA6). The thickness of the gas barrier layer may be 1 μm to 25 μm or 2 μm to 15 μm.

Next, a method for sealing the packaging container according to the present invention will be described with reference to FIG.

As shown in FIG. 3, as a premise, the container body M shown in FIG. 1 is used. In the container body M, the distance d of the seal portion 32 shown in FIG. 2 is 0.3 mm, and the component may be any non-foaming material. The lid body N is a molded lid, and includes a flat lid body flange portion Nf. The sealing machine P has a pressure of 0.35 MPa to 1.0 MPa, a time of 0.5 seconds to 5 seconds, and a temperature of 100 ° C. to 200 ° C. At the time of heat sealing by the sealing machine P, the cushion C for pressurization is placed from the back side of the main body flange portion 3 of the container main body M.

As shown in FIG. 3A, the sealing machine P applies pressure from the surface side of the lid flange portion Nf of the lid N. The lid flange portion Nf first contacts the apex 32a of the seal portion 32. When the lid flange portion Nf is continuously pressurized by the sealing machine P, the sealing portion 32 is gradually crushed. At this time, although not shown, the seal portion 32 may expand in the lateral direction while the flange inner end edge portion 31 and the flange outer end edge portion 33 move outward. Then, the inside and outside of the apex 32a of the seal portion 32 gradually come into surface contact with the lid flange portion Nf.
As shown in FIG. 3B, when the area of the sealing portion 32 in surface contact with the lid flange portion Nf increases with the pressurization of the sealing machine P, the back side of the sealing portion 32 finally becomes the cushion C. In surface contact, the height of the apex 32a of the seal portion 32 becomes equal to the height of the flange inner end edge portion 31 and the flange outer end edge portion 33, the seal portion 32 becomes flat, and the entire main body flange portion 3 is formed. The entire surface of the seal portion 32 is bonded to the lid flange portion Nf in a flat manner over the circumference.
As shown in FIG. 3C, when the container body M and the lid N are removed from the sealing machine P and the cushion C, the opening portion of the container body M is sealed with the lid N. At this time, there is no gap between the seal portion 32 and the lid flange portion Nf, and the container body M and the lid N are adhered to each other with a desired seal strength. In this state, the main body flange portion 3 and the lid flange portion Nf may be distorted due to the elasticity of the seal portion 32 or the distortion of the material.

M Container body 1 Main body bottom 2 Main body side wall 3 Main body flange 31 Flange inner edge 32 Seal 32a Apex 33 Flange outer edge

Claims (1)

A packaging container including a lid, a container body made of polyethylene terephthalate sealed by the lid and having a circular shape in a plan view.
The container body is provided with a flange portion that is formed in an arch shape and seals the lid body.
The flange portion includes an inner end edge portion located inside the container body, an outer end edge portion located outside the inner end edge portion and at the same height as the inner end edge portion, and the inner end edge portion. It has a portion and a vertex located equidistant from the outer edge portion.
The inclination angle on the inner edge side and the inclination angle on the outer edge side are equivalent.
A packaging container characterized in that the vertical distance from the virtual line connecting the inner end edge portion and the outer end edge portion to the apex is 0.2 mm to 0.4 mm .

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