JP7638519B2 - Container with lid - Google Patents

Description

The present invention relates to a container with a lid.

Cup-shaped containers made by deep drawing polystyrene are used as containers for storing food contents such as yogurt. For example, such cup-shaped containers include a lidded container 100 shown in FIG. 1, which has multiple cup-shaped container bodies 10 and flange portions 20, with adjacent cup-shaped container bodies 10 connected by the flange portions 20, and a film-like lid portion 30 that closely contacts the surface of the flange portions 20 to seal the contents. With such a lidded container 100, one serving of yogurt can be stored in each cup-shaped container body 10, and four servings of yogurt can be sold as one product.

In the lidded container 100, a notch 40 is formed in the flange portion 20 between adjacent cup-shaped container bodies 10. The notch 40 penetrates the lid portion 30 and is formed in the thickness direction of the flange portion 20.

Figure 2 is a schematic side cross-sectional view of the flange portion 20 near the notch 40. In order to reduce the weight of the cup-shaped container, the cup-shaped container body 10 and the flange portion 20 are formed by deep drawing a laminated sheet for deep drawing, which has a laminated structure in which a foamed polystyrene layer 52 is sandwiched between non-foamed polystyrene layers 51 and 53 (for example, Patent Document 1).

JP 2018-12239 A

Figure 3 shows how to separate individual cup-shaped container bodies 10 from a container with lid 100. For example, when a consumer purchases a container with lid 100 containing yogurt, the consumer separates one cup-shaped container body 10 from the container with lid 100 when eating a serving of yogurt, and then opens the lid 30 to eat the yogurt. Here, in order to separate one cup-shaped container body 10 from the container with lid 100, the consumer applies force with both hands from the lid 30 to dent the flange portion 20 with the notch 40, thereby folding the flange portion 20 (Figure 3(b)). This action allows one cup-shaped container body 10 to be easily separated (Figure 3(c)).

However, some consumers may attempt to separate the cup-shaped container body 10 by tearing it apart rather than folding it as shown in FIG. 3.

For example, when dividing a lidded container 100 having four cup-shaped container bodies 10 into two cup-shaped container bodies 10 on the left and two on the right along the notch 40 on dotted line A in Figure 1, one action can be to hold the two left cup-shaped container bodies 10 with the left hand and the two right cup-shaped container bodies 10 with the right hand, and then, while still holding the two left cup-shaped container bodies 10 with the left hand, to tear off the two right cup-shaped container bodies 10 by twisting them up and down (arrows C, C') with the right hand.

When the cup-shaped container body 10 is divided by such a tearing action, burrs 70 are generated in the divided portion 60 (Fig. 3C) after division. The generation of burrs is problematic because not only do the burrs spoil the appearance of the divided portion 60, but also there is a risk of fingers being injured if they come into contact with the burrs.

In view of the above problems, the present invention aims to provide a container with lid 100 having a laminated structure in which a foamed polystyrene layer 52 is sandwiched between non-foamed polystyrene layers 51 and 53, and in which no burrs 70 are generated at the divided portion 60 even when the cup-shaped container body 10 is divided by tearing along the notch 40.

Figure 4 is a schematic diagram of the cup-shaped container body 10 and the divided portion 60 on which burrs 70 have occurred. Figure 4(a) is a schematic diagram based on a photograph of the burrs 70 of the divided portion 60 taken from the cup-shaped container body 10 side, and Figure 4(b) is a schematic diagram based on a photograph of the burrs 70 of the divided portion 60 taken from the lid portion 30 side. The divided portion 60 in Figure 4(a) and the divided portion 60 in Figure 4(b) are flange portions 20 with notches 40 formed therein before division, and after division, a divided portion 60 of a shape corresponding to the divided portion 60 in Figure 4(a) is formed in Figure 4(b), and the divided portion 60 protruding from the lid portion 30 in Figure 4(b) becomes a burr 70.

The inventors conducted an investigation to determine the cause of the generation of burrs 70 using a cup-shaped container body 10 with a divided portion 60 as shown in Figures 4(a) and (b) as a test specimen. As a result, it was found that burrs 70 were generated by a fracture in an area where no notch 40 was formed in the polystyrene foam layer 52, as shown in the schematic cross-sectional view of the flange portion 20 in the divided portion 60 as shown in Figure 4(c).

Further testing revealed that such burrs 70 occur when the tip 41 of the notch 40 is in the polystyrene foam layer 52 (Figure 2(a)) or when the tip 41 does not reach the polystyrene foam layer 52.

Based on these results, we investigated a mode in which burrs 70 would not occur, and found that if the notch 40 penetrates the lid portion 30, the non-foamed polystyrene layer 51, and the foamed polystyrene layer 52, and the tip 41 of the notch 40 reaches the non-foamed polystyrene layer 53 (Figures 5(a) and (b)), then burrs 70 would not occur at the divided portion 60 even if the cup-shaped container body 10 is divided by the above-mentioned tearing action, which led to the completion of the present invention.

That is, in order to solve the above-mentioned problems, the lidded container of the present invention is a lidded container for sealing contents, comprising a plurality of cup-shaped container bodies for storing the contents, a flange portion extending outward from the upper edge of the cup-shaped container body and connecting adjacent cup-shaped container bodies, a film-like lid portion that seals the contents by coming into close contact with the surface of the flange portion, and a notch formed in the flange portion between adjacent cup-shaped container bodies, penetrating the lid portion and in the thickness direction of the flange portion, wherein the cup-shaped container body and the flange portion are integrally molded plastic, and the plastic has a laminated structure in which a first layer consisting of a non-foamed layer of polystyrene, a second layer consisting of a foamed layer of polystyrene, and a third layer consisting of a non-foamed layer of polystyrene are laminated in this order, the surface of the first layer is the inner surface of the container and is the surface of the flange portion that comes into close contact with the lid portion, the surface of the third layer is the outer surface of the container, the notch penetrates the first layer and the second layer, and the tip of the notch reaches the third layer.

The foaming ratio of the foam layer of the second layer may be 1.3 to 2.5 times.

The first layer may have a thickness of 200 μm to 250 μm, the second layer may have a thickness of 100 μm to 150 μm, and the third layer may have a thickness of 550 μm to 700 μm.

The depth of the notch in the thickness direction of the flange portion may be 300 μm to 500 μm.

The capacity of the container body may be 50 mL to 200 mL.

According to the present invention, it is possible to provide a container with a lid that has a laminated structure in which a foamed polystyrene layer is sandwiched between non-foamed polystyrene layers, and that does not generate burrs at the divided portion even when the cup-shaped container body 10 is divided by tearing along the notch.

FIG. 1 is a schematic perspective view of a container with lid 100. 2 is a schematic cross-sectional side view of the flange portion 20 in the vicinity of a notch 40. FIG. 1A and 1B are diagrams showing how to separate individual cup-shaped container bodies 10 from a container with lid 100. 1 is a schematic diagram of a cup-shaped container body 10 and a divided portion 60 in which a burr 70 has occurred. 2 is a schematic cross-sectional side view of a flange portion 20 in the vicinity of a notch 40 of a lidded container 100 of the present invention. FIG.

Below, one embodiment of a lidded container according to the present invention will be described with reference to the drawings.

[Container with lid 100]
The container with lid 100 of the present invention is a container for sealing the contents. The contents may be liquid or solid foods and beverages such as yogurt, pudding, egg tofu, dressing, sauce, jelly, etc., medicines, cosmetics, etc.

The capacity of the cup-shaped container body 10 of the lidded container 100 is not particularly limited, but for example, when sealing one serving of the above-mentioned food or drink, the capacity of the cup-shaped container body 10 is 50 mL to 200 mL.

<Configuration of lidded container 100>
Fig. 1 shows a schematic perspective view of a container with lid 100, which is an example of a container with lid. The container with lid 100 includes a plurality of cup-shaped container bodies 10 for storing contents, a flange portion 20 that spreads outward from the upper edge of the cup-shaped container body 10 and connects adjacent cup-shaped container bodies 10, a film-like lid portion 30 that seals the contents by closely contacting the surface of the flange portion 20, and a notch 40 that penetrates the lid portion 30 and is formed in the thickness direction of the flange portion in the flange portion 20 between adjacent cup-shaped container bodies 10. Note that, although the cup-shaped container bodies 10 are arranged in two rows of two each in Fig. 1, four cup-shaped container bodies 10 may be arranged in one row, or a plurality of cup-shaped container bodies 10 may be arranged in one row or multiple rows.

Typically, the contents are placed in the cup-shaped container body 10, the contents are sealed with the lid 30, the notch 40 is then formed, and the container is then delivered to the consumer.

(Cover portion 30)
The lid 30 may be a laminated film, similar to the lid of a commonly used container with a lid. For example, it may be a laminated film composed of a surface substrate layer/sealant layer, or a surface substrate layer/adhesive layer/aluminum foil layer/sealant layer. Examples of the surface substrate layer include polyester resins such as polyethylene terephthalate (PET), polyamide resins, polypropylene resins, etc. The sealant layer is, for example, an adhesive plastic such as an acrylic acid alkyl ester-vinyl chloride-vinyl acetate copolymer, and is usually peelably attached to the flange 20 by heat sealing. The shape of the lid 30 may be any shape that covers the surface of the flange 20 and can be bonded to the flange 20. The lid 30 may be larger than the outer periphery of the flange 20, or may have the same outer periphery as the flange 20.

(Cup-shaped container body 10, flange portion 20)
The cup-shaped container body 10 and the flange portion 20 are made of a single piece of molded plastic, and as shown in the schematic side cross-sectional view of the flange portion 20 near the notch 40 of the lidded container 100 shown in Figure 5, the plastic has a laminated structure in which a first layer 51 consisting of a non-foamed layer of polystyrene, a second layer 52 consisting of a foamed layer of polystyrene, and a third layer 53 consisting of a non-foamed layer of polystyrene, which are described below, are laminated in that order.

The surface of the first layer 51 is the inner surface of the lidded container 100 and is the surface of the flange portion 20 that is in close contact with the lid portion 30. The surface of the third layer 53 is the outer surface of the lidded container 100.

(First layer 51)
The first layer 51 is made of a non-foamed layer of polystyrene, which is a polymer with styrene as a monomer and is a plastic resin. Examples of the polystyrene of the first layer 51 include HIPS (high impact polystyrene) which has improved impact resistance by adding a rubber component, and GPPS (general purpose polystyrene) which is highly transparent and hard. The first layer 51 can be formed by using these alone or in combination.

The first layer 51 may also contain a colorant. The colorant may be any of the general colorants used to color plastics. Examples include white, black, red, blue, green, and yellow dyes, pigments, masterbatches, colored pellets, colored compounds, dry colors, and paste colors. Colors may be prepared by combining one or more of these colorants.

(Second layer 52)
The second layer 52 is made of a polystyrene foam layer, which is a polymer with styrene as a monomer and is a plastic resin. Examples of the polystyrene for the second layer 52 include HIPS (high impact polystyrene) with improved impact resistance by adding a rubber component, and GPPS (general purpose polystyrene) which is highly transparent and hard. The second layer 52 can be formed using these alone or in combination.

The second layer 52 may also contain a colorant. The colorant may be any of the general colorants used to color plastics. Examples include white, black, red, blue, green, and yellow dyes, pigments, masterbatches, colored pellets, colored compounds, dry colors, and paste colors. Colors may be prepared by combining one or more of these colorants.

The second layer 52, which is made of a foamed polystyrene layer, can be formed by adding a chemical foaming agent or a physical foaming agent during the manufacturing process and foaming the foaming agent.

Examples of chemical foaming agents include mixtures of sodium hydrogen carbonate and citric acid, organic substances such as azodicarbonamide, azobisisobutyronitrile, diazoaminobenzene, N,N'-dinitrosopentamethylenetetraamine, N,N'-dimethyl-N,N'-dinitroterephthalamide, benzenesulfonyl hydrazide, and p,p'-oxybisbenzenesulfonyl hydrazide, and hydrogen carbonates such as sodium hydrogen carbonate and ammonium hydrogen carbonate. Of these, a mixture of sodium hydrogen carbonate and citric acid is preferably used, and the foaming gas generated is carbon dioxide gas. In addition, talc, clay, etc. may be used as a foaming nucleating agent, and citric acid may be used as a foaming assistant.

The method of adding the chemical foaming agent is not particularly limited as long as a normal foam layer is formed. Methods that can be used include dry blending with a mixture or molten kneaded product of various raw resins, adding the agent using a quantitative feeder in the hopper of an extruder, or creating and adding a master batch based on a polystyrene resin.

The amount of these chemical foaming agents added is adjusted according to the desired expansion ratio, and although the amount varies depending on the type, they can generally be mixed in a ratio of about 0.1 to 5.0 parts by mass per 100 parts by mass of polystyrene.

Physical foaming agents are used in a method of extruding polystyrene while injecting a foaming gas into it, or in a method of extruding polystyrene that has already been impregnated with a foaming gas. Physical foaming agents include those that are gaseous at room temperature (25°C) and normal pressure (1 atm), such as nitrogen, carbon dioxide, propane, n-butane, i-butane, and dimethyl ether.

(Expansion Ratio of Second Layer 52)
The expansion ratio of the foam layer of the second layer 52 is preferably 1.3 to 2.5 times. If the expansion ratio is less than 1.3 times, the weight of the lidded container 100 may not be sufficiently reduced. If the expansion ratio exceeds 2.5, the bubbles in the foam layer may cause unevenness on the surface of the flange portion 20, which may impair the appearance of the lidded container 100. In consideration of reducing the weight of the lidded container 100, the expansion ratio is more preferably 1.7 to 1.9 times.

The expansion ratio can be calculated by measuring the specific gravity of the laminated structure and the specific gravity of a non-foamed layer of the same composition as the laminated structure that has been extruded separately using an electronic specific gravity meter, Alpha Mirage's MDS-300, calculating the specific gravity of the foamed layer from the ratio of the thicknesses of the foamed layer and non-foamed layer of the laminated structure, and then dividing the specific gravity of the non-foamed layer by the specific gravity of the foamed layer.

(Third layer 53)
The third layer 53 is made of a non-foamed layer of polystyrene, which is a polymer with styrene as a monomer and is a plastic resin. Examples of the polystyrene of the third layer 53 include HIPS (high impact polystyrene) which has improved impact resistance by adding a rubber component, and GPPS (general purpose polystyrene) which is highly transparent and hard. The third layer 53 can be formed by using these alone or in combination.

The first layer 51 and the third layer 53 may be formed from resins of the same composition, or from resins of different compositions. For example, the first layer 51 and the third layer 53 may be layers of the same composition, in which HIPS and GPPS of the same product are mixed in the same mixing ratio, or the first layer 51 and the third layer 53 may be layers of different compositions, in which HIPS and GPPS purchased from different manufacturers are mixed in different mixing ratios.

The third layer 53 may also contain a colorant. The colorant may be any of the general colorants used to color plastics. Examples include white, black, red, blue, green, and yellow dyes, pigments, masterbatches, colored pellets, colored compounds, dry colors, and paste colors. Colors may be prepared by combining one or more of these colorants.

(Notch 40)
The notch 40 is formed in the thickness direction of the flange portion 20, penetrating the cover portion 30, and also penetrating the first layer 51 and the second layer 52, with the tip 41 of the notch 40 reaching the third layer 53 (FIG. 5).

It is important that the notch 40 penetrates the second layer 52, which is a foamed layer of polystyrene. For example, as shown in FIG. 2, if the tip 41 of the notch 40 is in the second layer 52 (FIG. 2(a)), or if the tip 41 is in the first layer 51 without reaching the second layer 52 (FIG. 2(b)), burrs 70 will be generated in the divided portion 60 when the cup-shaped container body 10 is divided by the tearing action described above.

Therefore, in order to prevent burrs 70 from occurring in the dividing portion 60, it is sufficient that the tip 41 of the notch 40 passes through the second layer 52 and reaches the third layer 53. For example, the tip 31 may be within the third layer 53 as shown in FIG. 5(a), or the tip 41 may be formed on the surface of the third layer 53 as shown in FIG. 5(b). In these cases, when one cup-shaped container body 10 is divided by the above-mentioned operation shown in FIG. 3, burrs 70 are not generated in the dividing portion 60, and even when the cup-shaped container body 10 is divided by the above-mentioned tearing operation, burrs 70 are not generated in the dividing portion 60.

The notch 40 can be formed, for example, by cutting the flange 20 together with the lid 30 with a blade such as a notch cutter after the contents have been placed in the cup-shaped container body 10 and sealed with the lid 30. The notch 40 may also be formed to have a V-shaped notch shape as shown in FIG. 5, or it may have an I-notch shape, which is a linear notch, a U-shaped notch, or a base notch shape, which is a home plate-shaped notch.

The depth D (Figure 5) of the notch 40 in the thickness direction of the flange portion 20 is preferably 300 μm to 500 μm. If the depth D of the notch 40 is less than 300 μm, the shallow depth D may make it impossible or difficult to separate the cup-shaped container body 10 from the lidded container 100. If the depth D of the notch 40 exceeds 500 μm, the deep depth D may cause the cup-shaped container body 10 to separate from the lidded container 100 even without any operation to separate the cup-shaped container body 10 from the lidded container 100, as an impact during transportation of the lidded container 100 or an impact if the lidded container 100 is dropped may be transmitted to the flange portion 20, causing the cup-shaped container body 10 to separate from the lidded container 100.

The length L of the breaking portion 80, calculated by subtracting the depth D from the thickness of the flange portion 20, can be, for example, 350 μm to 700 μm. The breaking portion 80 is a portion that breaks when the cup-shaped container body 10 is separated from the lidded container 100. If the length L is less than 350 μm, even if no operation is performed to separate the cup-shaped container body 10 from the lidded container 100, the impact during transportation of the lidded container 100 or the impact when the lidded container 100 is dropped may be transmitted to the flange portion 20, causing the cup-shaped container body 10 to separate from the lidded container 100. If the length L is longer than 700 μm, it may be impossible or difficult to separate the cup-shaped container body 10 from the lidded container 100.

[Thickness of the first layer 51, the second layer 52 and the third layer 53]
The sum of the thicknesses of the first layer 51, the second layer 52, and the third layer 53 is the thickness of the plastic, i.e., the thickness of the cup-shaped container body 10 and the flange portion 20, and the thickness of the plastic can be determined taking into consideration the cost of raw materials, durability, etc. The thickness of each layer can be set taking into consideration the depth D of the notch 40 and the length L of the breaking portion 80. For example, the condition is that the depth D is equal to or greater than the sum of the thicknesses of the first layer 51 and the second layer 52 so that the tip 41 of the notch 40 passes through the second layer 52 and reaches the third layer 53.

Taking the above into consideration, for example, the thickness of the first layer 51 can be set to 200 μm to 250 μm, the thickness of the second layer 52 can be set to 100 μm to 150 μm, and the thickness of the third layer 53 can be set to 550 μm to 600 μm.

The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples.

[Manufacturing example of sheet for container with lid]
Based on the formulation shown in Table 1, the raw materials were melt-mixed, and then a two-kind three-layer co-extruder was used to obtain a deep-drawing laminated sheet in which the second layer 52 was laminated between the first layer 51 and the third layer 53 as a sheet for a lidded container, so that the first layer 51 had a thickness of 250 μm, the second layer 52 had a thickness of 100 μm, and the third layer 53 had a thickness of 550 μm. In detail, the raw materials blended for the first layer 51 and the third layer 53 were supplied to a single extruder (diameter 65 mm, L/D: 32), and the raw materials blended for the second layer 52 were also supplied to a single extruder (diameter 130 mm, L/D: 32), and nitrogen gas was injected from the injector of the single extruder at a pressure of 47 MPa and a flow rate of 0.011 kg/hr, and the raw materials melt-mixed at a predetermined temperature from each extruder were supplied to a two-kind three-layer feed block type T die. The three-layer sheet was extruded through a die adjusted to an appropriate lip clearance, rolled with three polishing rolls, and cooled to room temperature to form a three-layer sheet with a total thickness of 900 μm, which was then wound into a roll to form a sheet for a lidded container. The expansion ratio of the second layer 52 was 1.5 times, and the expansion ratio could be adjusted by the gas injection pressure and flow rate.

The raw materials used for the sheet for lidded containers were 475D (manufactured by PSJ) as HIPS, HF77 (manufactured by PSJ) or HMT1 (manufactured by Toyo Styrene Co., Ltd.) as GPPS, and PS-NX0326 (manufactured by Nikko Bix) as white pigment.

The sheet for the container with lid manufactured as described above is deep-drawn to form the body and flange, the contents are placed inside, the lid is put on, and then a notch is formed to complete the container with lid of the present invention.

(summary)
As described above, the present invention is industrially useful because it can provide a lidded container having a laminated structure in which a foamed polystyrene layer is sandwiched between non-foamed polystyrene layers, and even when the cup-shaped container body is separated by tearing along a notch, no burrs are generated at the separated portion.

10 Cup-shaped container body 20 Flange portion 30 Lid portion 40 Notch 41 Tip 51 Non-foamed layer of polystyrene (first layer)
52 Polystyrene foam layer (second layer)
53 Non-foamed polystyrene layer (third layer)
60 Divided portion 70 Burr 80 Fracture portion 100 Container with lid A Dotted line C Arrow C' Arrow

Claims (6)

A container with a lid for sealing the contents,
A plurality of cup-shaped container bodies for accommodating the contents;
A flange portion that extends outward from an upper edge of the cup-shaped container body and connects adjacent cup-shaped container bodies;
A film-like lid portion that seals the contents by being in close contact with the surface of the flange portion;
a notch formed in the flange portion between adjacent cup-shaped container bodies in a thickness direction of the flange portion by penetrating the lid portion;
Equipped with
The cup-shaped container body and the flange portion are made of a plastic and are integrally molded.
The plastics are, in order, comprised of a first layer of non-foamed polystyrene;
a second layer comprising a foamed layer of polystyrene;
a third layer comprising a non-foamed layer of polystyrene;
The laminated structure includes:
a surface of the first layer is an inner surface of the container and is a surface of the flange portion that is in close contact with the lid portion;
the surface of the third layer is an outer surface of the container;
the notch penetrates the first layer and the second layer, and a tip of the notch reaches the third layer.
Container with lid. The container with lid according to claim 1, wherein the foaming ratio of the foamed layer of the second layer is 1.3 to 2.5 times. The first layer has a thickness of 200 μm to 250 μm,
The second layer has a thickness of 100 μm to 150 μm,
The thickness of the third layer is 550 μm to 700 μm.
The container with lid according to claim 1 or 2. The container with lid according to any one of claims 1 to 3, wherein the depth of the notch in the thickness direction of the flange portion is 300 μm to 500 μm. The container with lid according to any one of claims 1 to 4, wherein the lid is a laminated film. The portion container according to any one of claims 1 to 5, wherein the capacity of the container body is 50 mL to 200 mL.

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