JP2002019760A - Heat-insulating container for food - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-insulating container for food which is excellent in heat-insulating property, can ensure a proper strength, and at the same time, can prevent a short shot from being generated even when a thin-molding by an injection-molding is performed, and of which the molding property is excellent, and which can be made light-weight. SOLUTION: For this heat-insulating container for food, vertical ribs 7 in the vertical direction are molded by the injection-molding in a manner to project under a radial state on the outer peripheral surface of a container main body 3 of a cylindrical shape having bottom. In such a heat-insulating container for food, the base section width T of the vertical rib 7 and the thickness t of the peripheral wall 3a of the container main body 3 satisfies relationship of t<=T<=4t.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to dried foods,
The present invention relates to a heat-insulating container for food, which is most suitable for storing a lump of food such as dried instant noodles that can be poured with boiling water and for storing low-temperature food such as a frozen product or a refrigerated product.

[0002]

2. Description of the Related Art Conventionally, instant foods such as instant instant noodles (dried noodles, snack noodles, and miso soup in a cup) and containers for hot coffee or very cold beverages have been considered in consideration of the danger of burns and easy holding. In addition, the container itself is devised for heat insulation.

For example, as the heat insulating container, a container formed by molding a foamed resin such as styrene foam or injection molding is employed. Particularly, recently, containers that are formed by injection molding using polypropylene as a material are currently being used because environmentally superior materials are demanded by society. In such containers by injection molding, vertical ribs are provided on the outer peripheral wall of the container so that even when hot water is poured into the container, the heat is not transmitted to a finger for grasping the container (Japanese Patent Application Laid-Open No. HEI 9-102572). No. 9-272571).

[0004]

[0005] As such a container, it is required to reduce the weight and thickness of the container in order to save resources, reduce waste (reduce garbage), and reduce costs. According to the injection molding in which a molten resin such as polyolefin or polystyrene is poured between a conventional convex core mold and a concave cavity mold, a short shot is easily generated at an end of the mold. There is a disadvantage that a thin molded product cannot be obtained. Here, the short shot refers to a molding failure that occurs when the resin does not reach the end of the mold (because the fluidity of the molten resin is deteriorated) during thin-wall molding by injection molding.

The present invention has been made in order to solve the above-mentioned problems. The present invention has excellent heat insulating properties and can secure an appropriate strength. In addition, it is possible to prevent short shots from occurring even when performing thin-wall molding by injection molding. It is an object of the present invention to provide a heat-insulating container for food which is excellent in weight and which realizes weight reduction.

[0006]

SUMMARY OF THE INVENTION The present invention has been made as an insulated container for food in order to solve the above problems,
A feature of the heat insulating container for food according to the present invention is that a vertical rib 7 is formed on the outer peripheral surface of the bottomed cylindrical container body 3 by injection molding so that a vertical rib 7 protrudes radially. In the heat insulating container, the base width T of the vertical rib 7 and the thickness t of the peripheral wall 3a of the container main body 3 have a relationship of t ≦ T ≦ 4t. The thickness t of the peripheral wall 3a of the container body 3 refers to the thickness of a portion between the vertical ribs 7 adjacent to each other.

The base width T of the vertical rib 7 and the container body 3
Since the thickness t of the peripheral wall 3a is in a relationship of t ≦ T ≦ 4t, a gap serving as the vertical rib 7 between the concave cavity mold and the convex core mold during injection molding. In addition, the resin easily flows in the gap that becomes the peripheral wall 3a, and the resin can be quickly and reliably filled to every corner of the cavity (molding space) between the cavity mold and the core mold.

In addition, it is made of a polypropylene resin having a melt index MI in the range of 50 to 100,
It is preferable that the thickness t is 0.2 mm ≦ t ≦ 0.6 mm.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a first embodiment of the present invention, and the container of the present embodiment illustrates an instant cup noodle mass (dry noodle) as an example of dry food.

The container 1 has a cup-shaped (bottomed cylindrical) container body 3. The container body 3 may have any suitable heat insulating property and heat resistance that can be used for a food container. For example, the container body 3 is formed of a plastic material such as polypropylene, high-density polyethylene, and polystyrene. In the case of the polypropylene resin described above, those having a melt index (MI) of 50 to 100 are preferable, and those having a melt index (MI) of 60 to 80 are particularly preferable.

A flange 2 is provided on the upper edge of the opening of the container body 3, and the flange 2 is peeled off by a sealing lid (not shown) made of, for example, a laminated material such as aluminum foil and a synthetic resin film or paper. Freely sealed.

The container body 3 is formed by injection molding so that the diameter decreases as it goes downward. On the outer peripheral surface of the peripheral wall 3 a of the container body 3, a number of vertical ribs 7 project radially, and each of the vertical ribs 7 is provided continuously in the vertical direction of the container body 3. At the upper part of the container body 3, a portion (large-diameter portion) 5 which is cylindrical and has no flat vertical ribs with no uneven surface is formed, and the upper end of each vertical rib 7 is formed on the large-diameter portion 5. It is connected.

The cross-sectional shape of each vertical rib 7 has a triangular or trapezoidal shape whose width decreases toward the tip, and the base width T of each vertical rib 7 and the wall thickness t of the peripheral wall of the container body 3 satisfy t ≦ t. It is formed so as to satisfy the relationship of T ≦ 4t. In addition, the container is the bottom plate 3b.
In the case of a container for ready-to-eat food having a diameter of 50 to 80 mm and a height of 70 to 130 mm, the thickness t of the peripheral wall of the container body 3
It can be applied within a range from 0.2 mm or more, at which practical strength of the container can be obtained, to 1.0 mm or less, which is liable to cause a short shot during injection molding.
In particular, when a polypropylene-based resin having an MI of 50 to 100 is used, it is possible to form a thin wall having a thickness t of 0.2 mm to 0.6 mm, which is preferable.

When the base width T of each vertical rib 7 is smaller than the thickness t of the peripheral wall 3a of the container body 3, the flow path of the resin is not formed, and the vertical rib does not function as a groove. Therefore, the molten resin is unlikely to flow sufficiently on either the peripheral wall or the vertical rib, and short shots are likely to occur. When the base width T of each vertical rib is larger than 4t,
While the flow to the vertical ribs is promoted because the resistance to the molten resin in the vertical rib direction is reduced, the container thin portion between the vertical ribs 7 and the adjacent vertical ribs 7 (the vertical ribs are not provided) The molten resin does not flow sufficiently on the peripheral wall of the portion), so that uniform molding cannot be performed, and short shots are likely to occur.

The peripheral wall 3a of the container body 3 between the vertical ribs 7
Plural (three in this embodiment) annular peripheral wall portions 9a, 9
b and 9c are formed so as to be continuous in a stepwise manner.

Each peripheral wall portion 9a, 9b, 9c is
Connected to each other. A container body 14 is provided such that an auxiliary piece 14a downwardly extending from a lower end of the upper peripheral wall portion 9a has a predetermined interval with the middle peripheral wall portion 9b and both ends are connected to the respective vertical ribs 7. 3 are formed in the circumferential direction.

A downward auxiliary piece 14b extends from the lower end of the middle peripheral wall 9b.

The vertical rib 7 is provided with the auxiliary pieces 14a, 14b.
And is inclined substantially parallel to the taper angle of the lower peripheral wall portion 9b. Here, in order to further enhance the heat insulating property of the container and reduce the material cost, the height H of the vertical rib 7 with respect to the lower peripheral wall 9c is 0.5 mm ≦ H
≦ 5 mm, particularly preferably 1.5 mm ≦ H ≦ 4 mm. Reference numeral 17 denotes a cylindrical leg integrally formed downward from the bottom wall 3b.

A heat-shrinkable cylindrical label 18 is fitted around the outer periphery of the peripheral wall 3a of the container body 3. On the inner surface of the label 18, a heat-sensitive adhesive which is activated by heat at the time of heat shrinkage of the label 18 and exerts adhesiveness is applied, and the upper portion of the label 18 is attached to the container body 3 via the heat-sensitive adhesive. It is adhered to the surface 5a of the large diameter portion 5. Accordingly, the label 18 is tapered along the vertical ribs 7, but is held without falling down from the container body 3. Further, a beautiful printed display can be obtained by the label 18.

When the container is manufactured, the container body is formed by injection molding using a core mold having a shape corresponding to the inner shape of the container body and a cavity mold having a shape corresponding to the outer shape of the container body. To manufacture. That is, the cavity mold is provided with an injection port at a position corresponding to the center of the bottom surface of the container body.

Then, the molten resin is injected under pressure from the injection port, and the peripheral wall is formed while forming a number of vertical ribs on the outer peripheral wall of the container. Since the flow of the molten resin is performed at a high pressure, it is instantaneous (for example, about 0.5 to 1 second).
The container body is formed as follows. The relationship between the base width T of the vertical rib 7 and the wall thickness t of the peripheral wall 3a of the container body 3 is defined as t ≦ t.
Since T ≦ 4t is set, the resin flows smoothly to the end of the cavity (peripheral wall and vertical rib), and a thin container body with good moldability can be formed.

The bottom plate 3b is made of polypropylene resin and has a diameter of 50 to 80 mm and a height of 70 to 130 mm.
The conditions for injection molding the instant food container are as follows. Injection pressure: 100 to 200 MPa Resin temperature (at the time of injection): 200 to 280 ° C Mold temperature: 10 to 20 ° C

When, for example, hot water is poured into the heat-insulating container having the above structure, even if the peripheral wall 3a corresponding to the grip portion of the container body 3 becomes hot, the vertical rib 7 has a heat radiation effect. Since the tip surface has a relatively low temperature and a small contact area with the finger to be gripped, it does not feel any particular heat.

Moreover, even if the container body 3 is relatively firmly gripped, the diameter of the peripheral wall 3a is smaller than that of the case where the peripheral wall 3a is a flat surface because the container body 3 has the radial ribs 7 formed radially. The strength in the direction is improved, and it is difficult to deform when the container body is gripped. In general, the synthetic resin tends to be slightly softened and its rigidity reduced by heating, but the auxiliary piece 14 is hard to be heated by hot water (contents) and can prevent the rigidity from being reduced.

FIGS. 3 and 4 show a second embodiment of the present invention. The same members and portions as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In the present embodiment, unlike the first embodiment, no step portion is provided in the container body 3. Therefore, the tip of the vertical rib 7 and the peripheral wall 3a of the container body 3
Is parallel to the entire length of the vertical rib 7. In this case, the height H of the vertical rib 7 is 1.5 to 4.0 m.
m is preferred.

The present invention is not limited to the above embodiment. For example, the container may be a container for hot coffee or a very cold beverage other than a container for storing dried noodles to be cooked in hot water. May be. Further, the shape of the container body 3 is not limited to a circular shape in a plan view, but may be any rectangular shape or an elliptical shape.

[0027]

EXAMPLE Injection molding was performed under the conditions shown in Table 1 using a propylene ethylene copolymer having an MI of 80, and
Has a wall thickness t of 0.25 and a base width T of vertical ribs of 0.7
mm, vertical rib height H is 1.5 mm (lowest point) to 3.5
The heat insulating container of the first embodiment set to mm (the highest point) was prepared (Example 1).

Injection molding was performed under the conditions shown in Table 1 using a propylene ethylene copolymer having an MI of 60, and the thickness t of the peripheral wall of the container body 3 was 0.5 and the base width T of the vertical rib was 0.5. A heat insulating container of the second embodiment in which the height of the vertical rib was set to 0.8 mm and the height H of the vertical rib was set to 1.9 mm (Example 2).

Further, as a comparative example, a heat insulating container was prepared in the same procedure as in Example 2 except that the base width T of the vertical rib was 0.4 mm (Comparative Example).

[0030]

[Table 1]

Then, the moldability of each sample heat insulating container was compared. The moldability was visually confirmed by a short shot around the upper opening of the sample heat insulating container. At this time, the one in which the number of short shots did not occur was regarded as good. In Examples 1 and 2, short shots were not observed and molding was good. On the other hand, in the comparative example, short shots occurred and the moldability was poor.

[0032]

As described above, in the container of the present invention, since the base width of the vertical rib provided on the container main body and the thickness of the peripheral wall of the container main body have a relationship of t ≦ T ≦ 4t, the heat insulating property is obtained. In addition to ensuring excellent strength and adequate strength, short shots hardly occur even when thin-wall molding is performed by injection molding, and the resulting container has excellent appearance and reduces defective products, thereby reducing production costs. There is.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a container according to a first embodiment of the present invention.

FIG. 2A is a cross-sectional plan view of a main part showing the vertical rib,
(B) is a bottom view of a main part showing the bottom surface of the container body.

FIG. 3 is a half sectional view of a container according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional plan view of a main part showing the vertical rib.

[Explanation of symbols]

3 ... container body, 3a ... peripheral wall, 7 ... vertical rib, T ... base width,
t: wall thickness of the surrounding wall

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroyuki Imai 5-3-18 Imazukita, Tsurumi-ku, Osaka F-Terminal in Fuji Seal Co., Ltd. (Reference) 3E033 AA08 BA16 CA08 FA02 GA02 GA03 3E067 AA03 AA11 AB01 BA02A BA07A BB14A BB15A BB16A BC03A CA18 EE07 FA01 FC01 GA11

Claims (2)

[Claims] 1. An outer peripheral surface of a bottomed cylindrical container body (3),
In a food heat insulating container formed by injection molding such that the vertical ribs (7) in the vertical direction project radially, a base width (T) of the vertical ribs (7) and a peripheral wall (3) of the container body (3) are formed. A heat insulating container for food, wherein the thickness (t) of 3a) is in a relationship of t ≦ T ≦ 4t. 2. The food according to claim 1, wherein the food comprises a polypropylene resin having a melt index (MI) in the range of 50 to 100, and the thickness (t) satisfies 0.2 mm ≦ t ≦ 0.6 mm. Insulated container for