JP2021130491A - Packing container and manufacturing method of packing container - Google Patents

Abstract

To provide a packing container which obtains a desired effect based on mixture of an inorganic filler, and has a characteristic which does not disturb at least a normal using manner.SOLUTION: A packing container M is obtained by thermo-forming of a synthetic resin sheet having a specific gravity of 1.3 or more. The packing container M comprises a bottom part 1, a rib part 11 formed in the bottom part 1, a side wall part 2 continuously prepared in an obliquely upper direction from the entire circumference of an outer end edge part 1a of the bottom part 1, and a flange part 3 continuously prepared in an outer direction from the entire circumference of an upper end edge of the side wall part 2. The rib part 11 comprises a rib outer wall part 11a built up circumferentially from the bottom part 1, and a rib inner wall part 11b which faces an inner side of the rib outer wall part 11a and is built up circumferentially from the bottom part 1.SELECTED DRAWING: Figure 1

Description

The present invention relates to a packaging container and a method for producing a packaging container, which are used for prepared foods such as bowls, noodles, hamburgers and pasta, and have strength and rigidity suitable for the usage mode.

Traditionally, for example, when selling bowls such as oyakodon and katsudon at supermarkets and convenience stores, rice (rice) and side dishes are served on a plastic container and the lid is closed so that consumers can easily take it home. Was there. Therefore, there has been a demand for a packaging container that is easy for consumers to hold and has strength and rigidity that can withstand the load during transportation and stacking.

For example, in Patent Document 1, a bottom surface portion having a circular shape in a plan view, which is obtained from a thermoformed resin sheet and smaller than the opening edge portion of the container body, and a side wall portion molded integrally with the opening edge portion and the bottom surface portion. The bottom surface is a packaging container having a circular projecting portion whose inner portion is one step higher than the outer peripheral edge and an annular groove located between the projecting portion and the outer peripheral edge and along the circumferential direction. Is disclosed. Generally, the protrusion of the bottom surface is formed for raising the bottom, and the groove is formed for increasing the strength and rigidity of the bottom surface.

Japanese Unexamined Patent Publication No. 2012-20782

However, Patent Document 1 does not disclose the correlation between the component ratio of the resin sheet and the strength and rigidity of the packaging container. That is, in Patent Document 1, when a packaging container is molded using a soft resin sheet due to the influence of the component ratio and a relatively heavy food containing bowls is stored, stress is applied to the protrusion and the groove. If you lift it in a concentrated manner, the bottom surface may bend due to the weight of the food.

In recent years, a filler (inorganic filler) has been added to a synthetic resin sheet before molding with the aim of developing desired strength, rigidity, heat resistance, and other various resistances in a packaging container after molding and reducing raw material costs. ing. There are many types of inorganic fillers, and the types and ratios to be blended are appropriately determined according to the function and application of the packaging container. In particular, in recent years, as interest in environmental issues has increased, efforts to reduce the amount of synthetic resin used have become active. Therefore, there is a possibility that a packaging container having a relatively low strength and rigidity as compared with a conventional packaging container will be widely used.

Therefore, an object of the present invention is to provide a packaging container which can obtain a desired effect by mixing an inorganic filler and has at least characteristics that do not interfere with a normal usage mode.

That is, the present invention is a packaging container obtained by thermoforming a synthetic resin sheet having a specific gravity of 1.3 or more, and includes a bottom portion and a rib portion formed on the bottom portion, and the rib portion is provided. Is characterized by including a rib outer wall portion that rises radially from the bottom portion, and a rib inner wall portion that rises radially from the bottom portion facing the inside of the rib outer wall portion.

Further, the present invention is a packaging container obtained by thermoforming a synthetic resin sheet having a melt flow rate (MFR) of 0.4 g / 10 min or more as a material constituting the sheet, and the bottom portion and the bottom portion thereof. The rib portion is provided with a rib outer wall portion that rises radially from the bottom portion, and a rib inner wall portion that faces the inside of the rib outer wall portion and rises radially from the bottom portion. It is characterized by having.

The rib portion includes an upper end of the rib outer wall portion and a rib top portion continuously provided from the upper end of the rib inner wall portion, and it is desirable that the rib top portion is separated from the bottom portion by 2 mm or more.

It is desirable that the rib outer wall portion is separated from the outer peripheral edge of the bottom portion by 6 mm to 25 mm.

It is desirable that the rib inner wall portion is separated from the rib outer wall portion by 2 mm or more.

It is desirable that the synthetic resin sheet contains less than 50% of the thermoplastic resin.

It is desirable that the packaging container is manufactured by a compressed air molding method.

According to the present invention, it is expected that a desired effect such as reduction of raw material cost by mixing an inorganic filler can be obtained, and at least an effect of obtaining a packaging container having characteristics such as strength and rigidity that does not interfere with a normal usage mode can be obtained. can.

It is a perspective view of the packaging container in one Embodiment of this invention. It is a top view of the said packaging container. It is a bottom view of the above-mentioned packaging container. It is a side view of the said packaging container. It is an enlarged end view of the XX portion in the YY end face shown in the plan view. It is a partially enlarged end view of the part shown in the enlarged end view. It is a partially enlarged end view which shows the design change example of the part shown in the enlarged end view. It is a process outline diagram of the manufacturing method of the packaging container in one Embodiment of this invention. It is a perspective view of another packaging container in one Embodiment of this invention. It is a perspective view of another packaging container in one Embodiment of this invention.

Hereinafter, the packaging container according to the embodiment of the present invention will be described with reference to FIGS. 1 to 5C. 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 shown by a broken line or an imaginary line (two-dot chain line), and a cross-sectional part is shown by hatching. In the description, the terms indicating the directions such as upward, downward, lateral, vertical, and horizontal are basically the positional relationships in which the packaging container is placed in the direction normally used.

<Overview of this packaging container>
As shown in FIGS. 1 to 4, the packaging container M has a circular bottom portion 1 in a plan view on which food is placed, and a convex rib portion 11 formed on the bottom portion 1 so as to protrude inside the container. And the side wall portion 2 provided continuously in the diagonally upward direction from the entire circumference of the outer end edge portion 1a of the bottom portion 1, and the flange portion 3 provided continuously in the outward direction from the entire circumference of the upper end edge portion 2 of the side wall portion 2. It has.

The present packaging container M corresponds to the container body. The packaging container M may be equipped with a dome-shaped lid (not shown) that is externally fitted and sealed to the flange portion 3. The lid body is provided with a concave groove in which the lower portion 1 of the bottom portion 1 of the main packaging container M is accommodated. That is, with the lid attached to the packaging container M, the lower portion of the bottom 1 of another packaging container fits in the groove of the lid, so that the stability of the stacked state can be expected to be improved. The depth (height from the lowermost end to the uppermost end) of the present packaging container M is not particularly limited, but may be 25 mm to 50 mm, preferably 30 mm to 45 mm, and 30 mm to 40 mm. More preferred. The food contained in the present packaging container M is, for example, related to bowls and noodles, but is not limited as long as it is heavy as a whole, for example, foods of 350 g or more and prepared foods.

The bottom portion 1 may be elliptical or rectangular in a plan view. Area of the bottom portion 1 is not particularly limited ^and may be a 30cm ² ~200cm ^2, preferably if 45cm ² ~160cm ^2, more preferably if 50cm ² ~150cm 2. An unnumbered radial rib may be provided between the outer edge portion 1a of the bottom portion 1 and the rib portion 11. Since the central side of the bottom portion 1 from the rib portion 11 is flat, it is easy to support label backing by an automatic label affixing device. The horizontal end surface of the side wall portion 2 and the outer end edge of the flange portion 3 at a predetermined height may have the same shape as or a different shape from the bottom portion 1 in a plan view. Even if the side wall portion 2 has a concave overlap stopper (hereinafter, also referred to as “stack”) at a predetermined position so that empty packaging containers are stacked one on top of the other and cannot be removed from each other. good.

<Material of this packaging container>
The present packaging container M is obtained by thermoforming a synthetic resin sheet, and is not particularly limited as long as it is relatively soft as a food packaging container, but melt of the material constituting the sheet. When the flow rate (MFR) is 0.4 g / 10 min or more, the effect of the present invention can be easily obtained. Further, when it is 0.7 g / 10 min or more, the effect of the present invention is more easily obtained, and when it is 0.8 g / 10 min or more, the effect of the present invention is more easily obtained. Here, the melt flow rate (MFR) may be measured by measuring a sample obtained by cutting a synthetic resin sheet into small pieces under the conditions of a temperature of 230 ° C. and a load of 21.18 N according to JIS K7210. If the melt flow rate (MFR) is, for example, 0.4 g / 10 min or more, the amount of drawdown increases in the manufacturing process as described later, and there is a concern that the molding method is limited. Here, the upper limit of the melt flow rate (MFR) is not particularly limited, but may be, for example, 10 g / 10 min.

Here, the resin constituting the synthetic resin sheet is not particularly limited, and examples thereof include polyester resins such as polyethylene terephthalate and thermoplastic resins such as polyolefin resins such as polyethylene and polypropylene. Further, in order to reduce the amount of resin, a filler (filler) such as paper powder or inorganic particles may be mixed. Here, the inorganic particles are, for example, particles of 100 μm to 10 nm, and are talc, calcium carbonate, silica, clay, wollastonite, potassium titanate, zonotrite, gypsum fiber, aluminum borate, and fibrous magnesium compound (MOS). ), Aramid fiber, carbon fiber (carbon fiber), glass fiber (glass fiber), mica, glass flakes, polyoxybenzoyl whiskers, etc., but it is possible to select a proven talc for packaging containers for food. preferable. Such inorganic particles (inorganic filler) may be used alone or in combination of two or more. The amount of the filler to be mixed with the thermoplastic resin may be, for example, 30% by mass or more, more preferably 50% by mass or more, and further preferably 52% by mass or more. The blending amount of the thermoplastic resin may be less than 70% by mass, more preferably less than 50% by mass, still more preferably less than 48% by mass.

Here, the thermoplastic resin described above may be a biomass-derived resin. Examples of such resins include biopolyethylene, biopolypropylene, and biopolyethylene terephthalate. By blending such a biomass-derived resin, the synthetic resin sheet may be softened, and the melt flow rate (MFR) may be lower than when the conventional petroleum-derived resin is used. , There is a concern that it will be easy to draw down. The blending amount of the biomass-derived resin is not particularly limited, but may be 5% by mass or less, 15% by mass or less, 35% by mass or less, and all of the resin content may be contained. It may be a biomass-derived resin.

<Material of this packaging container>
The present packaging container M may be obtained by thermoforming a synthetic resin sheet having a specific gravity of 1.3 or more, and is relatively heavy and soft as a food packaging container. Such a synthetic resin sheet having a specific gravity of 1.3 or more may be made of a mixed material of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) and an inorganic filler (talc), and may contain a polyolefin resin. The amount may be less than 50% by mass, and the blending amount of the inorganic filler may be 50% by mass or more. More specifically, it may be 30 to 50% by mass of the thermoplastic resin and 50 to 70% by mass of the inorganic filler, or 40 to 49% by mass of the thermoplastic resin and 51 to 60% by mass of the inorganic filler. Further, the specific gravity may be 1.35 or more, and when it is 1.4 or more, the effect of the present invention can be more easily obtained. Here, the upper limit of the specific gravity is not particularly limited, but may be 2.0, for example.

<Details of rib part>
As shown in FIG. 5A, the rib portion 11 includes a rib outer wall portion 11a that rises radially from the bottom portion 1 and a rib inner wall portion 11b that rises radially from the bottom 1 facing the inside of the rib outer wall portion 11a. In other words, the rib portion 11 has a shape similar to the outer edge portion 1a which is the outline of the bottom portion 1 in a plan view, and the annular rib outer wall portion 11a and the rib inner wall portion 11b protruding inward from the outside of the container. To be equipped with. The "circumferential shape" means a shape that returns to the above-mentioned place when traced from a predetermined place, and may or may not have unevenness, and the plan view shape may be circular, oval, or rectangular. Well, not limited.

According to this configuration, for example, when the main packaging container M is held in one hand while containing food, stress is concentrated at an arbitrary position on the bottom portion 1, but the rib outer wall portion 11a and the rib inner wall portion 11b make the bottom portion 1 Since the strength and rigidity are increased, the bottom 1 is hard to bend. That is, the stress due to the weighting of the contents is concentrated at an arbitrary position on the bottom 1 and tries to bend with the finger touching the back surface of the bottom 1 as a fulcrum, but the rib outer wall portion 11a located on the center side of the bottom 1 from the fulcrum Since the stress is dispersed on the rib inner wall portion 11b, the bottom portion 1 is less likely to bend, and the effect of being able to safely hold it with one hand can be expected.

The rib outer wall portion 11a and the rib inner wall portion 11b are preferably linear in order to secure desired rigidity and strength, but may be a bulging curved shape or a curved curved shape. As shown in FIG. 5B, the rib outer wall portion 11a and the rib inner wall portion 11b have an end face gazebo shape (extended end) inclined by 5 ° to 20 ° with respect to a vertical surface in order to secure the strength and rigidity of the bottom portion 1. It is preferably 7.5 ° to 15 °, more preferably 8 ° to 12 °, but the inclination angle of the rib outer wall portion 11a and the inclination angle of the rib inner wall portion 11b are different. It may be different, and may be square or rectangular in terms of end face perpendicular to the horizontal plane.

The rib portion 11 includes a rib outer peripheral edge portion 11d and a rib inner peripheral edge portion 11e corresponding to a boundary with the bottom portion 1, and a rib outer wall base portion 11f that forms the lower side of the rib outer wall portion 11a continuously from the rib outer peripheral edge portion 11d. And the rib inner wall base portion 11g which forms the lower side of the rib inner wall portion 11b continuously from the rib inner peripheral edge portion 11e. The rib outer wall base portion 11f and the rib inner wall base portion 11g are preferably curved in order to secure desired strength and rigidity, but may have an angular shape intersecting with the bottom portion 1. Small ribs that are not numbered may be provided on the entire circumference or a part of the rib outer wall base portion 11f and / or the rib inner wall base portion 11g.

In order to secure the strength and rigidity of the bottom portion 1, the rib portion 11 is preferably not uneven in the vertical direction and has the same height continuously in the circumferential direction, but has a stack at a predetermined position. You may.

The rib portion 11 further includes an upper end of the rib outer wall portion 11a and a rib top portion 11c having a flat end surface view provided continuously from the upper end of the rib inner wall portion 11b. The height H of the rib top 11 is 2 mm to 10 mm, but is not limited, as long as it is 2 mm or more from the bottom 1 and lower than 1/3 of the depth of the main packaging container M. More preferably, it is 2 mm to 5 mm.

According to this configuration, the rib outer wall portion 11a and the rib inner wall portion 11b are supported by the rib top portion 11c to increase the strength and rigidity of the bottom portion 1, and when the height H of the rib top portion 11 is 2 mm or less, the rib outer wall portion 11a Since the stress is easily dispersed on the rib inner wall portion 11b, the bottom portion 1 is less likely to bend.

As shown in FIG. 5C, the rib portion 11 is continuous with the rib inner wall portion 11b and is continuous with the rib inner wall portion 11b with respect to the outer bottom portion 1 m located outside the rib portion 11 (the outer peripheral edge side of the bottom portion 1). The inner bottom portion 1n located on the inner side (center side of the bottom portion 1) may be arranged higher than the mounting surface. In other words, the height H1 from the surface of the outer bottom portion 1 m, which corresponds to the vertical height of the rib outer wall portion 11a, to the upper end surface of the rib top portion 11, corresponds to the vertical height of the rib inner wall portion 11b. The height from the surface of the inner bottom portion 1n to the upper end surface of the rib top portion 11 may be higher than the height H2, the difference between the height H1 and the height H2 may be 5 mm or less, or 2 mm or less. It is preferably 1 mm or less, and more preferably 1 mm or less. However, considering the strength, it is preferable that H1 = H2.

In order to secure the rigidity and strength of the bottom portion 1, the rib top portion 11c preferably has an angular end-view flat shape intersecting the rib outer wall portion 11a and the rib inner wall portion 11b, but has an arc-shaped end face (dome shape). It may be.

The rib outer wall portion 11a is separated from the outer peripheral edge 1a of the bottom portion 1 by 6 mm to 25 mm. Specifically, the distance W1 between the rib outer peripheral edge portion 11d and the outer peripheral edge 1a of the bottom portion 1 is 6 mm to 25 mm, preferably 7 mm to 20 mm, and more preferably 8 mm to 16 mm.

According to this configuration, if the distance W1 is shorter than 6 mm, the rib outer wall portion 11a is located substantially equivalent to the fulcrum or on the outer peripheral edge 1a side of the fulcrum, and if the distance W1 is longer than 25 mm, the rib outer wall portion Since the 11a is too far from the fulcrum, it is possible to prevent the stress from being concentrated at an arbitrary position on the bottom 1, so that the bottom 1 is less likely to bend.

The rib inner wall portion 11b is separated from the rib outer wall portion 11a by 2 mm or more. Specifically, the distance W2 corresponding to the distance between the upper end of the rib outer wall portion 11a and the upper end of the rib inner wall portion 11b, which are the same height, is 2 mm or more, and is 1/20 to 1/10 of the diameter of the bottom portion 1. If this is the case, it may be 2 mm to 6 mm, but more preferably 2 mm to 4 mm, and even more preferably 2 mm to 3 mm.

According to this configuration, when the distance W2 is shorter than 2 mm, the rib top portion 11c cannot fully support the rib outer wall portion 11a and the rib inner wall portion 11b, and the stress is difficult to disperse. Since the stress is easily dispersed in the portion 11a and the rib inner wall portion 11b, the bottom portion 1 is less likely to bend.

<The content of thermoplastic resin>
The synthetic resin sheet may contain less than 50% of the thermoplastic resin. That is, it may contain less than 50% of a thermoplastic resin and the balance may be composed of a filler other than the resin. According to such a configuration, the amount of resin can be reduced while ensuring the strength and rigidity of the entire packaging container M.

<Inorganic filler content>
The synthetic resin sheet may be made of a synthetic resin containing 50% or more of an inorganic filler. If the amount of the inorganic filler is less than 50%, the content of the synthetic resin material such as PP (polypropylene) increases, so that the strength and rigidity of the entire packaging container M increase. The effect is hard to expect.

<Manufacturing method of this packaging container>
As shown in FIG. 6, the method for producing the present packaging container M is not particularly limited, but it is preferable to use a hot plate compressed air vacuum forming method (also referred to as a compressed air forming method). As an example of the manufacturing process, specifically, first, a synthetic resin sheet that is continuously fed out from the roll state and placed on the hot plate is placed on the lower side and air is evacuated downward to create a vacuum state. Heat in close contact with the surface of the hot plate. Next, the heated synthetic resin sheet is placed in close contact with the surface of the mold (female mold) in a vacuum state by extracting air upward from the lower side of the hot plate and molding the hot plate.

According to this method, after heating the synthetic resin sheet with the heaters arranged on the upper and lower sides, the air is evacuated downward and brought into close contact with the surface of the mold (male mold) in a vacuum state. The effect of avoiding the draw-down phenomenon that occurs during vacuum forming can be expected. That is, since the synthetic resin sheet has a specific gravity of 1.3 or more, it is heavier and softer than a normal thermoplastic resin, and if it is fed to the mold after heating, it may hang down due to its own weight. The hot plate pressure air vacuum forming method, which can be molded in the same place without the need for molding, is preferable for molding the main packaging container M.

In addition, since the packaging container by the hot plate pressure air vacuum forming method is molded by stretching the synthetic resin sheet so as to press it against the mold (female mold), the thickness of the bottom farthest from the surface of the mold is the side wall before molding. Since it is relatively thinner than other parts such as the part, the peculiar effect obtained by the rib part 11 described above can be expected. The characteristic of the container obtained by the hot plate compressed air vacuum forming method is that the thickness of the flange portion is thicker than the thickness of the bottom portion.

Next, with reference to FIGS. 7 and 8, a portion different from the above-mentioned packaging container will be described with respect to another packaging container according to the embodiment of the present invention, and the description of the equivalent portion will be omitted. Parts or parts equivalent to those shown in FIGS. 1 to 5 are numbered uniformly by adding 100 in FIGS. 1 to 5 in FIGS. 7 and 8 for easy reference.

As shown in FIG. 7, the packaging container 100M includes a substantially elliptical bottom portion 101 in a plan view and a convex rib portion 110 formed on the bottom portion 101. Further, as shown in FIG. 8, the packaging container 200M includes a substantially rectangular bottom portion 201 in a plan view and a convex rib portion 210 formed on the bottom portion 201.

The packaging container M may be formed by thermoforming a synthetic resin sheet by, for example, vacuum forming, thermoforming air forming, vacuum forming air forming, double-sided vacuum forming, or the like. It is preferable to select the thermoforming vacuum forming method. The synthetic resin sheet may be, for example, a polyester resin such as polyethylene terephthalate or an olefin resin such as polyethylene or polypropylene, and a single-layer or multi-layer sheet may be used, and may be colored or colorless and transparent, or opaque. It may be made of non-foamed resin. Further, the front surface or the back surface of the sheet may be covered with a synthetic resin film, and when the front surface is covered, printing may be performed. In the present invention, it is easier to obtain the effect by selecting a non-foamed resin synthetic resin sheet than a foamed resin synthetic resin sheet in which strength can be obtained by foaming.

The thickness of the main packaging container after molding is not particularly limited, but the thickness of the flange portion may be 0.25 mm to 0.7 mm, more preferably 0.25 mm to 0.5 mm, and 0. It is more preferably 35 mm to 0.45 mm. The thickness of the bottom portion may be 0.18 mm to 0.5 mm, more preferably 0.2 mm to 0.45 mm, and even more preferably 0.22 mm to 0.4 mm.

M Packaging container, 1 bottom, 1a outer edge, 11 ribs, 11a rib outer wall, 11b rib inner wall, 11c rib top, 2 side walls, 3 flanges

Claims (7)

A packaging container obtained by thermoforming a synthetic resin sheet having a specific density of 1.3 or more.
At the bottom
With a rib portion formed on the bottom portion,
The rib portion is
The rib outer wall that rises from the bottom in a circumferential shape,
A packaging container including a rib inner wall portion that faces the inside of the rib outer wall portion and rises from the bottom portion in a circumferential manner. A packaging container obtained by thermoforming a synthetic resin sheet having a melt flow rate (MFR) of 0.4 g / 10 min or more as a material constituting the sheet.
At the bottom
With a rib portion formed on the bottom portion,
The rib portion is
The rib outer wall that rises from the bottom in a circumferential shape,
A packaging container including a rib inner wall portion that faces the inside of the rib outer wall portion and rises from the bottom portion in a circumferential manner. The rib portion includes an upper end of the rib outer wall portion and a rib top portion continuously provided from the upper end of the rib inner wall portion.
The packaging container according to claim 1 or 2, wherein the rib top is separated from the bottom by 2 mm or more. The packaging container according to any one of claims 1 to 3, wherein the rib outer wall portion is separated from the outer peripheral edge of the bottom portion by 6 mm to 25 mm. The packaging container according to any one of claims 1 to 4, wherein the rib inner wall portion is separated from the rib outer wall portion by 2 mm or more. The packaging container according to any one of claims 1 to 5, wherein the synthetic resin sheet contains less than 50% of a thermoplastic resin. A method for manufacturing a packaging container, which comprises manufacturing the packaging container according to any one of claims 1 to 6 by a compressed air molding method.

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