JP2006056559A - Cup-shaped container with bottom wall having improved gas barrier property and light screening property and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cup-shaped container equipped with enough gas barrier properties and light screening properties by a simple structure by using an existing mold for in-mold molding, and a method for manufacturing it. <P>SOLUTION: The cup-shaped container 10 is formed by injection molding of a synthetic resin, and has a film or a metal foil 20 with gas barrier properties or light screening properties integrated on the inside or outside of the side wall 10b. At least the side wall 10b is formed of a first synthetic resin 11 injected beforehand so as to be integrated with the film or the metal foil 20, and at least a bottom wall 10a is composed of the first synthetic resin 11 injected in advance and a second synthetic resin 12 injected afterward into the first synthetic resin 11 and having the gas barrier properties and the light screening properties. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cup-shaped container integrally formed by injection molding of a synthetic resin, in particular, a gas barrier property that is not adversely affected by oxygen in the air, or a light-shielding property that is not adversely affected by sunlight or the like. And a manufacturing method thereof.

  The cup-shaped container integrally molded by synthetic resin injection molding has a large capacity, is hygienic, and can be mass-produced at a low cost. Various containers have been proposed as containers for dried foods such as seaweed, and as containers for dessert foods such as cut fruits and fruit jelly.

  As such a cup-shaped container, most are integrally molded from one kind of synthetic resin such as polypropylene and polyethylene as shown in FIG. For example, a film-like “lid” that describes the manufacturer is heat-sealed, for example, to achieve high sealing performance.

  By the way, even for such cup-shaped containers, depending on the drinks and foods to be stored, sufficient gas barrier properties that are not adversely affected by oxygen, water vapor, etc. in the air, or sufficient light shielding that is not adversely affected by sunlight, etc. It has been required to have a property. In other words, there is an increasing need for this type of cup-shaped container to enable long-term storage of contents.

  Therefore, a cup-shaped container as shown in FIG. 5B has been developed. In this cup-shaped container, a gas barrier property or light shielding film or metal foil is integrally formed on the inside or outside of the side wall, and the required gas barrier property or light shielding property is enhanced by this film or metal foil. Is.

  However, in the cup-shaped container shown in FIG. 5 (b), the gas barrier property or light-shielding property for the bottom wall is not ensured. Then, it is expected that oxygen in the air and ultraviolet rays from a fluorescent lamp illuminating the display shelf can enter from this bottom wall, and adversely affect the contents.

Therefore, it is necessary to increase the gas barrier property and the light shielding property for the bottom wall of this type of cup-shaped container. Various techniques for that purpose have been proposed in, for example, Patent Documents 1 to 3. It is coming.
JP 2000-177784 A, summary, representative diagram Patent No. 2741848 publication, claims, representative figure Japanese Patent No. 2730392, claims, representative figure

  The technique described in Patent Document 1 relates to “injection-molded containers for microwave ovens”. From the summary description, “they have excellent barrier properties against oxygen, water vapor, etc., and are decorative. For the purpose of “providing an injection molding container for microwave ovens that is excellent in, etc., and is useful for filling and packaging various articles”, as shown in FIG. The resin film having the above structure adheres the label laminated as a barrier substrate layer, and further has at least a vapor-deposited thin film of an inorganic oxide in the layer structure on the surface of the flange portion. The resin film has a configuration in which a lid member laminated as a barrier base material layer is closely bonded.

  However, according to the description in paragraph 0012 of Patent Document 1, the container described in Patent Document 1 is “label 5a laminated as a barrier base material layer” and “outer wall surface of bottom wall 3”. “The label 5b is used on the entire surface” and “the label 5b can be melted and integrated and closely adhered is not shown, but the center of the label 5b is open”. Two types of “5a” and “5b” must be set in the injection molding machine. Setting these two types of labels 5a and 5b in an injection molding machine is very difficult in the present situation where a large amount of containers of this type must be produced at high speed.

  In addition, in the technique of Patent Document 1, since “the center of the label 5b is opened”, the gas barrier property and the light shielding property of the portion where the label 5b is integrated are not sufficient by the “opening”. It is considered a thing.

  Patent Document 2 describes “barrier in-mold labeling container and method for producing the same”, but this technique is also described as “in-mold labeling as shown in FIG. The label having a barrier property is configured for the bottom wall and the side wall surface, the bottom surface label has a larger diameter than the inner surface or the outer surface of the container bottom, and the side wall surface label includes at least the outer wall surface of the container side wall and the yarn bottom. By placing both labels in the injection mold and molding the resin with the same size, the bottom label is formed on the inner surface of the container side wall or the inner surface of the yarn bottom and formed on the bottom of the container. The side wall surface label is a “barrier in-mold labeling container” formed on the outer peripheral surface of the container side wall and the outer peripheral surface of the yarn bottom.

  Since the barrier-type in-mold labeling container of this Patent Document 2 is also "configured with a label having a barrier property to be in-mold labeling for the bottom surface and the side wall surface", as in the case of Patent Document 1, Not only is it difficult to set the label for the bottom surface and the label for the side wall surface to the injection molding machine, but the close contact with both mold surfaces is not sufficiently compensated, so it is considered that a beautiful finish cannot be achieved.

  The technique of Patent Document 3 relates to “a container with legs molded by an in-mold label and a manufacturing method thereof”, and as shown in FIG. 8, “a container with legs molded by an in-mold label. The label has a side surface portion and a bottom surface portion, has a through hole at a position corresponding to the injection hole of the injection machine, and has a notch at a position where a leg portion is formed, and the label The layer structure is at least 3 layers, the outermost layer and the innermost layer are made of the same material as the container body, and the intermediate layer is made of a film having barrier properties. , "Legged container".

  Also in the container of Patent Document 3, “the shape of the label is composed of a side surface portion and a bottom surface portion and has a through hole at a position corresponding to the injection hole of the injection machine”. As with the technique of Patent Document 1, problems are considered to occur in the gas barrier property and the light shielding property.

  Accordingly, the present inventors have completed the present invention as a result of various studies on how to provide a cup-shaped container having sufficient gas barrier properties or light shielding properties.

  That is, the object of the present invention is to provide a cup-shaped container having a sufficient gas barrier property or light-shielding property with a simple structure using an existing in-mold mold (equipment), and a method for producing the same. There is to do.

In order to solve the above problems, first, the means taken by the invention according to claim 1 will be described with reference numerals used in the description of the best mode described below.
“A cup-shaped container 10 formed by injection molding of a synthetic resin and integrated with a film or metal foil 20 having a gas barrier property or a light shielding property inside or outside the side wall 10b,
At least the side wall 10b of the cup-shaped container 10 is formed of the first synthetic resin 11 previously injected to be integrated with the film or the metal foil 20,
At least the bottom wall 10a of the cup-shaped container 10 is first injected with the first synthetic resin 11 and the second synthetic resin 12 is injected into the first synthetic resin 11 later and has gas barrier properties or light shielding properties. A cup-shaped container 10 characterized by comprising
It is.

  That is, the cup-shaped container 10 according to the first aspect is integrally formed by synthetic resin injection molding, but as shown in FIG. As shown in 1 (b), a film or metal foil 20 having a gas barrier property or a light shielding property is integrated inside the side wall 10b.

  That is, the cup-shaped container 10 is provided with a first synthetic resin 11 previously injected to be integrated with the film or the metal foil 20 and later injected into the first synthetic resin 11 to provide gas barrier properties or light shielding properties. The second synthetic resin 12 is used. In this case, as shown in FIGS. 2 and 3, the first synthetic resin 11 and the second synthetic resin 12 are injected from the center of the portion that becomes the bottom wall 10 a, and each cup-shaped container 10 is formed. The parts are evenly injected.

  In the cup-shaped container 10, at least the bottom wall 10 a has a sandwich structure with the inner second synthetic resin 12 and the first synthetic resin 11 enveloping the second synthetic resin 12. The gas barrier property or light shielding property of the synthetic resin 12 enhances the gas barrier property or light shielding property of the bottom wall 10a.

  In addition, since the bottom wall 10a is thin, the second synthetic resin 12 constituting this part may come out from the part of the first synthetic resin 11 enclosing this part to the surface side. The complete sandwich structure may not be achieved. However, since the cup-shaped container 10 of the present invention is made for the purpose of enhancing the gas barrier property or the light shielding property of the bottom wall 10a, the second synthetic resin 12 is moved from the part of the first synthetic resin 11 to the surface side. However, the gas barrier property or light shielding property of the bottom wall 10a is still improved.

  Of course, since the injection of the second synthetic resin 12 is performed while pushing the first synthetic resin 11 in the molten state previously injected as described in the manufacturing method of claim 3 described later, the entire bottom wall 10a is The second synthetic resin 12 is molded in a state of being wrapped by the first synthetic resin 11, that is, the bottom wall 10a may have a sandwich structure with the outer first synthetic resin 11 and the inner second synthetic resin 12. Normally, the second synthetic resin 12 does not have holes or partial cuts, and its gas barrier property or light shielding property is perfect.

  Then, due to the gas barrier property or light shielding property of the second synthetic resin 12 and the film or metal foil 20, the cup-shaped container 10 is sufficiently equipped with gas barrier property or light shielding property as a whole. .

  In this type of cup-shaped container 10, as described in the background section above, a lid made of a film or metal foil 20 is heat-sealed on the flange 13 integrally formed on the periphery of the upper end opening. Therefore, the gas barrier property or light shielding property of the upper end opening of the cup-shaped container 10 is secured by this lid.

  Therefore, the cup-shaped container 10 according to claim 1 has a gas barrier property or a light shielding property by the film or the metal foil 20 on the side wall 10b and a gas barrier property or a light shielding property of the second synthetic resin 12 in the bottom wall 10a. Since the second synthetic resin 12 is injected while pressing the first synthetic resin 11 previously injected, it has a sufficiently thin gas barrier property or light shielding property. The bottom wall 10a that must be provided can easily ensure its gas barrier property or light shielding property.

Moreover, in order to solve the said subject, the means which the invention which concerns on Claim 2 took about the cup-shaped container 10 of the said Claim 1,
“The tip of the second synthetic resin 12 coincides with or overlaps the lower end of the film or metal foil 20 integrated with the side wall 10b”.
It is what.

  That is, in the cup-shaped container 10 according to the second aspect, as shown in FIG. 1, the tip of the second synthetic resin 12 sandwiched in the bottom wall 10a is integrated with the inner side or the outer side of the side wall 10b. The film or metal foil 20 is made to coincide with or overlap with the lower end.

  In this way, no gap or hole that impedes the gas barrier property or the light shielding property is generated at the boundary between the bottom wall 10a and the side wall 10b having the function of the gas barrier property or the light shielding property. 10 can have sufficient gas barrier properties or light shielding properties.

  Therefore, according to the cup-shaped container 10 of the second aspect, the film or metal foil 20 and the second synthetic resin 12 are in a tightly bonded state in addition to performing the same function as that of the first aspect. The function of gas barrier property or light shielding property is further ensured.

Further, the means taken by the invention according to claim 3 is:
“At least the bottom wall 10a is composed of the first synthetic resin 11 injected earlier and the second synthetic resin 12 injected later into the first synthetic resin 11 and having gas barrier properties or light shielding properties. The manufacturing method of the cup-shaped container 10 which goes through the following process.

(1) A step of attaching a film or metal foil 20 having gas barrier properties or light shielding properties to one of the molds 30 forming the cavities 34 for forming the cup-shaped container 10;
(2) A step of closing the mold 30 to form the cavity 34 while the film or the metal foil 20 is placed in a predetermined position in the cavity 34;
(3) After injecting the first synthetic resin 11 into the cavity 34, the step of injecting the second synthetic resin 12 having gas barrier properties or light shielding properties into the first synthetic resin 11 "
It is.

  That is, the manufacturing method of claim 3 relates to a method of manufacturing the cup-shaped container 10 according to the above-mentioned claims 1 and 2, and the cup-shaped container 10 having an improved gas barrier property or light-shielding function as a whole. It is a method for manufacturing.

  In the manufacturing method of claim 3, first, in step (1), a film or metal foil 20 having gas barrier properties or light shielding properties is placed on one of the molds 30 that form the cavities 34 for forming the cup-shaped container 10. Wear it. Here, as a method of attaching the film or the metal foil 20 to one of the molds 30, as shown in FIG. 2, a method of attaching the lower mold 32 into which the core 33 is inserted to the outer periphery of the hole serving as the cavity 34. Although not shown, there are two methods of attaching to the outer periphery of the core 33 integral with the upper die 31. If the film or metal foil 20 is attached to the outer periphery of the hole serving as the cavity 34, the film or metal foil 20 is positioned outside the side wall 10b as shown in FIG. The film or the metal foil 20 is positioned inside the side wall 10b as shown in FIG. 1 (a).

  Next, in step (2), the mold 30 is closed and the cavity 34 is formed as shown in FIG. 3 while the film or metal foil 20 attached to one of the molds 30 is placed in a predetermined position in the cavity 34. To do. In the case shown in FIG. 3, the film or metal foil 20 is located inside the side wall 10b. However, when the film or metal foil 20 is attached to the core 33, the film or metal foil 20 is located outside the side wall 10b.

  In step (3), in the case of the best mode to be described later, the first synthetic resin 11 is injected into the cavity 34 from the gate 35 formed in the lower mold 32 as shown in FIG. After the first synthetic resin 11 is injected into the cavity 34 while leaving a space for the second synthetic resin 12 to be injected next, as shown in FIG. The second synthetic resin 12 having a gas barrier property or a light shielding property is injected, and the cavity 34 is completely filled with the second synthetic resin 12 and the first synthetic resin 11. In the best mode, the gate 35 into which the second synthetic resin 12 is injected is the same as that into which the first synthetic resin 11 is injected. After that, the first synthetic resin 11 and the second synthetic resin 12 are cooled by a generally employed method, the mold is opened, and the cup-shaped container 10 is taken out.

  Therefore, according to this manufacturing method, the cup-shaped container 10 according to claim 1 or 2 having the above-described effects can be easily and reliably manufactured with the existing mold 30.

As described above, in the present invention,
“A cup-shaped container 10 formed by injection molding of a synthetic resin and integrated with a film or metal foil 20 having a gas barrier property or a light shielding property inside or outside the side wall 10b,
At least the side wall 10b of the cup-shaped container 10 is formed of the first synthetic resin 11 previously injected to be integrated with the film or the metal foil 20,
At least the bottom wall 10a of the cup-shaped container 10 is first injected with the first synthetic resin 11 and the second synthetic resin 12 is injected into the first synthetic resin 11 later and has gas barrier properties or light shielding properties. It was composed by
The main feature of the structure is that the cup-shaped container 10 having a sufficient gas barrier property or light-shielding property can be provided with a simple structure using an existing in-mold mold. is there.

In the invention according to claim 3,
“At least the bottom wall 10a is composed of the first synthetic resin 11 injected earlier and the second synthetic resin 12 injected later into the first synthetic resin 11 and having gas barrier properties or light shielding properties. The manufacturing method of the cup-shaped container 10 which goes through the following process.

(1) A step of attaching a film or metal foil 20 having gas barrier properties or light shielding properties to one of the molds 30 forming the cavities 34 for forming the cup-shaped container 10;
(2) A step of closing the mold 30 to form the cavity 34 while the film or the metal foil 20 is placed in a predetermined position in the cavity 34;
(3) After injecting the first synthetic resin 11 into the cavity 34, the step of injecting the second synthetic resin 12 having gas barrier properties or light shielding properties into the first synthetic resin 11 "
The cup-shaped container 10 according to claim 1 or claim 2 having the above-described effects can be easily and reliably manufactured with the existing mold 30. .

  Next, the invention according to each claim configured as described above will be described with respect to the cup-shaped container 10 which is the best mode shown in the drawings. In this description, the manufacture of the cup-shaped container 10 according to the best mode will be described. The method will also be described.

  1 (a) and 1 (b) are longitudinal sectional views of a cup-shaped container 10 according to the present invention. The cup-shaped container 10 is integrally formed by injection molding of a synthetic resin. Thus, a film or metal foil 20 having a gas barrier property or a light shielding property is integrated inside or outside the side wall 10b.

  That is, the cup-shaped container 10 is formed by integrally forming a film or metal foil 20 by injection molding of a synthetic resin. The film or metal foil 20 is formed as shown in FIG. There are two types, that is, the case of being integrated with the outside of the side wall 10b and the case of being integrated with the inside of the side wall 10b as shown in FIG.

  As shown in FIG. 1 (a) or (b), the cup-shaped container 10 includes a first synthetic resin 11 previously injected to be integrated with the film or the metal foil 20, and the first synthetic resin 11. It is injected later and formed with the second synthetic resin 12 having gas barrier properties or light shielding properties.

  And at least the bottom wall 10a of this cup-shaped container 10 is injected into the first synthetic resin 11 previously injected to integrate the film or metal foil 20 and later injected into the first synthetic resin 11 to provide gas barrier properties. Or it is formed with the 2nd synthetic resin 12 provided with the light-shielding property, but the 2nd synthetic resin 12 is inject | emitted so that it may spread over the whole bottom wall 10a. Accordingly, the bottom wall 10a has a sandwich structure with the second synthetic resin 12 on the inside and the first synthetic resin 11 enclosing the second synthetic resin 12. The gas barrier property of the second synthetic resin 12 or The light shielding property enhances the gas barrier property or light shielding property of the bottom wall 10a.

  In addition, in the cup-shaped container 10 of the best mode, the thickness of the bottom wall 10a is about 0.5 mm to 1.5 mm.

  Moreover, in this cup-shaped container 10 of the best mode, as shown in FIG. 1, the tip of the second synthetic resin 12 overlaps with the lower end of the film or metal foil 20 when viewed from the side. Of course, the tip of the second synthetic resin 12 may coincide with the lower end of the film or the metal foil 20. In this way, no gap or hole that impedes the gas barrier property or the light shielding property is generated at the boundary between the bottom wall 10a and the side wall 10b having the function of the gas barrier property or the light shielding property. It has a necessary gas barrier property or light shielding property.

  The first synthetic resin 11 for constituting the cup-shaped container 10 has to have a high gas barrier property or light-shielding property because it must flow in the cavity 34 having a narrow interval to be the bottom wall 10a or the side wall 10b. Although not, a resin suitable for injection molding, such as polypropylene or polyethylene, is employed. On the other hand, since the second synthetic resin 12 must have high gas barrier properties or light shielding properties, for example, EVOH, MXD6Nylon, or PVDC is adopted.

  Of course, the film or metal foil 20 may be a conventionally used one, such as aluminum foil, aluminum-deposited synthetic resin film, or a synthetic resin film that has been colored or printed, including a layer with high light-shielding and gas barrier properties. do it.

  A flange 13 is integrally formed on the periphery of the upper end opening of the cup-shaped container 10, and the flange 13 is made of a film or a metal foil 20 as described in the background section above. It is common practice to heat seal the lid. For this reason, the gas barrier property or light-shielding property of the upper-end opening part of the cup-shaped container 10 is ensured by this lid.

  The cup-shaped container 10 as described above is manufactured by injection molding using the mold 30 as follows. First, as shown in FIG. 2, a film or metal foil 20 having a gas barrier property or a light shielding property is attached to the lower die 32 of the die 30 that forms the cavity 34 for forming the cup-shaped container 10. Here, as a method of attaching the film or the metal foil 20 to the mold 30, as shown in FIG. 2, the lower mold 32 into which the core 33 is inserted is attached to the outer periphery of the hole serving as the cavity 34. Although not shown, there are two methods, that is, attaching to the outer periphery of the core 33 integral with the upper die 31. If the film or metal foil 20 is attached to the outer periphery of the hole serving as the cavity 34, the film or metal foil 20 is positioned outside the side wall 10b as shown in FIG. The film or the metal foil 20 is positioned inside the side wall 10b as shown in FIG. 1 (a).

  Next, while the film or metal foil 20 attached to the lower mold 32 of the mold 30 is placed in a predetermined position in the cavity 34, the upper mold 31 is moved so that the core 33 is inserted as shown in FIG. The cavity 34 is formed by moving it. In the case shown in FIG. 3, the film or metal foil 20 is located inside the side wall 10b. However, when the film or metal foil 20 is attached to the core 33, the film or metal foil 20 is located outside the side wall 10b.

  Then, as shown in FIG. 3, the first synthetic resin 11 is injected from the gate 35 formed in the lower mold 32 into the cavity 34. After the first synthetic resin 11 is injected into the cavity 34 with a space for the second synthetic resin 12 to be injected next, as shown in FIG. The second synthetic resin 12 is injected and the cavity 34 is completely filled with the second synthetic resin 12 and the first synthetic resin 11. After that, the first synthetic resin 11 and the second synthetic resin 12 are cooled by a generally employed method, the mold is opened, and the cup-shaped container 10 is taken out.

The cup-shaped container which concerns on this invention is shown, (a) is the case where a film or metal foil is located in the outer side of a side wall, (b) is a longitudinal cross-section which shows the case where a film or metal foil is located inside a side wall FIG. It is a type | mold which manufactures the cup-shaped container, Comprising: It is a fragmentary longitudinal cross-section which shows the state just before the core is inserted in the lower mold | type side. It is a type | mold which manufactures the cup-shaped container, Comprising: It is a fragmentary longitudinal cross-section which shows the state by which the 1st synthetic resin was inject | poured in the cavity formed by the core being inserted in the lower mold | type side. It is a partial longitudinal cross-sectional view of the type | mold which shows the state by which the following 2nd synthetic resin was inject | emitted in the cavity. 1 shows a conventional cup-shaped container, in which (a) is a view in which a film or a metal foil is not integrated, and (b) is a longitudinal cross-sectional view in which a film or a metal foil is integrated on the outside. is there. It is a longitudinal cross-sectional view of the cup-shaped container which shows a prior art and integrated the film or metal foil on the outer side. It is a partial expanded sectional view of the bottom part of the cup-shaped container which shows another prior art. It is a perspective view which shows other prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cup-shaped container 10a Bottom wall 10b Side wall 11 1st synthetic resin 12 2nd synthetic resin 12a Tip 13 Flange 20 Film or metal foil 21 Lower end 30 Mold 31 Upper mold 32 Lower mold 33 Core 34 Cavity 35 Gate

Claims (3)

A cup-shaped container formed by injection molding of a synthetic resin and integrated with a film or metal foil having a gas barrier property or a light shielding property on the inside or outside of the side wall,
At least the side wall of the cup-shaped container is formed by the first synthetic resin previously injected to be integrated with the film or the metal foil,
At least the bottom wall of the cup-shaped container is composed of the first synthetic resin injected first and the second synthetic resin injected later into the first synthetic resin and having gas barrier properties or light shielding properties. A cup-shaped container characterized by that.   2. The cup-shaped container according to claim 1, wherein a tip of the second synthetic resin coincides with or overlaps a lower end of a film or metal foil integrated with the side wall. A cup-shaped container having at least a bottom wall composed of a first synthetic resin injected first and a second synthetic resin injected later into the first synthetic resin and having gas barrier properties or light shielding properties The method of manufacturing through the following steps.
(1) A step of attaching a film or metal foil having a gas barrier property or a light shielding property to one of molds for forming a cavity for forming the cup-shaped container;
(2) The step of closing the mold and configuring the cavity while the film or the metal foil is placed in a predetermined position in the cavity;
(3) A step of injecting a second synthetic resin having a gas barrier property or a light shielding property into the first synthetic resin after injecting the first synthetic resin into the cavity.

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