JPH046036A - Double container and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a container of excellent heat insulating effect and to improve rigidity of the container itself by a method wherein an inside container of synthetic resin and an outside container of synthetic resin or paper as main material are overlapped cocentrically, and expandable resin is interposed between an outside surface of the inside container and an inside surface of the outside container. CONSTITUTION:An expandable resin 15 is coated partially or entirely on an outside surface of an inside container 14 and dried once. In this instance, the coating pattern of the expandable resin 15 is not limited and a dot pattern and a grid pattern may be available. Thus expandable coated inside container is then inserted into a core die 16 and covered by an outside container 11 which is larger than, but has substantially the same shape as the inside container 14. After that, a cavity die 17 which has substantially the same shape of recessed part as the outside container 11 is inserted with respect to the outside container 11. Then the inside container 14 and the outside container 11, while overlapped one on the other and set between the core die 16 and the cavity die 17, are led into an appropriated furnace and heated for 30-60 seconds at a temperature between 100-140 deg.C.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates primarily to a food container with a double structure for storing heated or cooled foods (including beverages) and a method for manufacturing the same. .

[Conventional technology and its problems] In trains, station kiosks, vending machines, etc.
Beverages such as coffee and soup are sold in a relatively hot state.On the other hand, it is not possible to hold the container in the heated state, such as pouring boiling water into the container and then eating or drinking it, such as with instant ramen. The number of sales formats in which this is the norm has been increasing recently. This also applies to chilled foods such as ice cream, and thus, containers for storing foods that have been heated or cooled as described above and that are used for eating and drinking by holding the whole container by hand are not recommended. , is configured to exhibit the following characteristics.

That is, so that the heat or cold inside the container is not directly transmitted to the outer wall of the container, the heat must be blocked (many have a double structure).

For example, as shown in FIG.
(See Utility Model Application Publication No. 51-129102), or as shown in Fig. In the double container, a large number of protrusions 4 are formed on the outer wall of the inner container, thereby providing rigidity to the container. However, these conventional types suffer from the following problems, and improvements have been desired.

In other words, all of the conventional types mentioned above are intended to actively form an air layer 3 on the side wall of the container, which is the most economical and has excellent heat insulation efficiency. In the structure, the inner container 1 and the outer container 2 are designated by the reference numeral 5.
As shown in Figure 2, since the rims of the containers are in contact with each other, the heat inside the container is transferred from that area to the outer container, making it difficult to grasp the container with your hands. . Additionally, if boiling water is poured into the container and the temperature rises to 100 to 120 degrees Celsius, the container itself becomes soft, and as a result, it may come into contact with either the inner container or the outer container. There is also the problem that the container may become too soft or become distorted when grasped, causing the contents to overflow from the mouth. Therefore, with such a structure, softening of the container could not be prevented unless the thickness of the side wall was made very large. Furthermore, in the container having the above structure, the taper angle of the side wall is different between the inner container and the outer container, as shown by symbols α and β in the same figure, so different molds must be used for each, etc. There were also some inconveniences in terms of production.

On the other hand, in the structure shown in FIG. 12, a large number of protrusions 4 are formed on the outer wall of the inner container, so the above-mentioned problems are less likely, but heat is still transferred from the protrusions to the outer container. The thermal insulation effect was not always satisfactory.

Means for Solving Problem U] Here, the present invention aims to obtain a container having a double structure of inside and outside, which has a higher heat insulation effect than the conventional type, and also improves the rigidity of the container itself. The following measures have been taken to improve this. That is, the invention attempts to achieve each of the above objects by interposing a foamable resin layer between the outer container and the inner container in a double-layered container. Specific means for this purpose will be described below. In the present invention, an inner container made of synthetic resin and an outer container made of synthetic resin or whose main material is paper are polymerized almost concentrically, and a gap between the outer surface of the inner container and the inner surface of the outer container is formed. More specifically, an inner container made of synthetic resin manufactured by vacuum forming or pressure forming and an outer container made of synthetic resin or whose main material is paper are arranged almost concentrically. The outer surface of the inner container and the inner surface of the outer container are bonded via a partially formed foamable resin, and an air layer is formed between the inner container and the outer container. The aim is to provide a double container in which both of the two coexist. Furthermore, regarding the manufacturing method, after molding the inner container by vacuum forming or pressure forming, a foaming resin liquid is partially or completely applied to the outer surface of the inner container, and then the inner container is It is fitted into the core mold, and then an outer container formed by the same vacuum forming method or pressure forming method, or an outer container mainly made of paper, is placed over the outside of the inner container, and a cavity mold is also fitted onto the outer container. The container is then heated to foam the resin liquid, and then cooled to remove the container from the mold, thereby making it possible to efficiently manufacture the double-layered container having the configuration described above. .

[Embodiment] The present invention will be specifically explained based on the embodiments shown in Figs. After that, the edges of the mouth are curled as shown by the symbol Lla. At this time, if necessary, a small hole for ventilation indicated by reference numeral 12 may be bored in the mouth edge portion or the bottom portion. Note that when molding the outer container 11, it is possible to use a resin with excellent printability, but in some cases, a paper sheet with good printability may be used to form the container 11.
It can also be bonded to the outer circumferential surface of. Reference numeral 13 indicates a surface printing portion applied to the outer peripheral surface of the container. As a specific example of the outer container 11, for example, polypropylene containing calcium carbonate is used as the material resin, the container side wall has an outer diameter (mouth) of 70 mm, the bottom has an outer diameter of 45 mm, and a wall thickness of 0.3. Finished in mm. The reason why PP containing calcium carbonate was used as the material is to improve the printability of the outer container.

As for the outer container, it can be a normal paper container, or it can be made of a composite material of paper and plastic, which is made by laminating paper with a plastic film such as PE. The structure as shown in FIG. 11 can also be adopted as shown in FIG. 11 having a seaming portion at the bottom.

Next, regarding the inner container, a synthetic resin inner container 14 having a structure as shown in FIG. 4 is molded using the same material as the outer container. That is, after forming according to the pressure forming method or vacuum forming method as described above, predetermined trimming is performed, and then the following foamable resin (also referred to as expandable resin) 15 is applied to the outer wall surface of the formed container. Polypropylene was used as the material for the inner container, the outer diameter of the container side wall (mouth) was 68 mmφ, the outer diameter of the bottom was 43 mmφ,
Finished with a wall thickness of about 0.3 gates.

Next, to explain the foamable resin, this resin is
A thermoplastic resin containing a foaming component, in which a volatile or decomposable blowing agent is added to the plastic or rubber substrate to generate an inert gas upon heating and transform the resin into a cellular structure. A solution-like paint made of
Although it can be applied by normal printing methods,
It can also be applied by brush painting, roll coating, dipping, etc. other than printing. Specific examples of the resin include commercially available New Diform (trade name of Dainichiseika Kagyobu) and Thermocell (trade name of Cemedine ■). Then, the foamable resin I5 is partially applied to the outer surface of the inner container 14 (the first,
(See Figure 4) or apply it to the entire surface and let it dry once. Note that the foamable resin 15 may be applied in a polka dot pattern as shown in the figure, or in a lattice pattern, and there is no restriction on the application form.

After the inner container coated with the foamable resin as described above is fitted into the core mold 16 as shown in FIG. Cover with the shaped outer container 11. After this, a cavity mold 17 having a concave portion having substantially the same shape as the outer container 11 is inserted into the outer container 11. This cavity mold 16 has the function of centering the outer container, and also has the function of receiving and stopping the foaming pressure of the foamable resin.

Thereafter, the inner container 14 and the outer container 11 are set between the core mold 16 and the cavity mold 17 in a stacked state, and
While still set, this is introduced into a suitable heating furnace and heated in the furnace at a temperature of 1.00 to 40°C for about 30 to 60 seconds. When operated in this way, the foamable resin 15 described above
foaming begins, and as the resin gradually expands and comes into contact with the inner wall of the outer container 11, the container 11 is pressed against the inner wall of the cavity to create a certain gap [8] between the resin and the inner container 14. Let it form.

Once the foaming is completed, the container is cooled down and then taken out from the mold.
Pressurized air is forced into the inner container 14 near the bottom through the container 14, thereby ejecting the container from the mold. Incidentally, since the above-mentioned foamable resin also has an adhesive function, both the inner and outer containers taken out of the mold are bonded to each other and become an integrated state. Furthermore, even if a resin without adhesive function is used, the coefficient of friction of the resin against the outer container after foaming becomes extremely large.
There is no separation between the outer container and the inner container.

Incidentally, after the inner container 14 is stacked on the outer container 11, the mouth edge 14a of the container 14 can be curled inward as shown in FIG. 6 to form a product. The purpose of this is to improve the mouthfeel when eating or drinking by directly touching the container of the present invention, so it is not necessarily necessary to link the container. In addition, since both the inner and outer containers are set concentrically, when linking the rim of the inner container, the rim of the inner container, which is softened and deafened, is shaped into the shape of the rim of the outer container ILa. It is sufficient to simply bend it along the inner container, and in this way the curl link portion 1.4a can also be easily formed on the inner container.

FIG. 7 is a diagram illustrating an example of mechanically manufacturing the integrated container, in which the core mold 16 is attached to an endless chain conveyor indicated by the reference numeral 20.
While moving the ceno intermittently, the core mold is covered with the inner container 14 when it reaches the operating position Then cover it with the outer container 1.

At that time, foamable resin 15 is preliminarily applied to the outer surface of the inner container.
Of course, it is coated with Then, each of the containers, together with the core mold I6, is transferred to a heating zone indicated by the reference numeral 21 in FIG. 7 via the endless encossing device 20. As shown in the figure, another endless chain conveyor 22 is installed over the cooling zone 21 disposed downstream of the heating zone. A pair of cavity molds 17 are attached. Therefore, this cavity mold is placed inside the heating zone to form the outer container 1.
1, the resin foams in the heated atmosphere of the zone at the same time as the container is fitted into the outside of the container 1, thereby obtaining a double-integrated container with inside and outside parts as described above. The container after foaming is introduced into the cooling zone 22 located adjacent to the heating sink, and then released from the core mold 16 by the action of the pressurized air at the discharge point indicated by the symbol Z. , and is discharged via the chute 24.

FIG. 8 shows another embodiment of the present invention, in which the bottom of the inner container L4b is formed into a hemispherical shape, and if it is shaped like this, it will be used to store ice cream, etc., for example. It provides convenience. This is because it can be scooped out to the bottom without leaving any residue. Figures 9 and 10 show the external appearance of the outer container 11. Figure 9 shows an example in which the outer container 11b is shaped like a rectangular cylinder, and Figure 10 shows an example in which it is shaped like a cylinder. shows the case where a lid 19 is applied.

The structure of the present invention is as explained above, and examples of the material of the container will be described below. For the inner container 14, it is a single layer product such as PP, PVC, PET or PS, or PP/Ny/PP, PP/PVDC/PP, PP.
Multilayer fields such as /EVOH/PP can be used.

The same applies to the outer container 11, or it is also possible to use paper as the main material.

When storing aromatic beverages or foods, the inner container should be made of a material with high gas barrier properties, such as PE.
It is preferable to mold using T or PET/Ny/PET.

[Effects of the Invention] In the container of the present invention, a foamable resin layer having countless air bubbles and having a high heat insulating effect is interposed between each double-layered container. This makes it possible to effectively prevent the transmission of .Furthermore, the resin layer firmly supports the space between the inner and outer containers, increasing the rigidity of the container itself. In particular, even if the wall thickness of the container itself is reduced, the resin layer between the containers exerts a reinforcing effect on the container, preventing the container from becoming soft, and as a result, the container as a whole becomes Another advantage is that it is a sturdy container that does not cause any discomfort to the user.

In addition, the outer surface of the outer container in the present invention is made of a material that can maintain a smooth flat surface and has excellent printability, so that the container can exhibit its cosmetic properties. However, it can provide a container with a high-class feel.

Note that if a small hole is made in the outer container that communicates with the atmosphere, a convection phenomenon will occur in the gap formed between the inner and outer containers, so it will be difficult to prevent the outer container from getting hot. Not only can it be used, but it can also be maintained at a temperature that is in equilibrium with the atmosphere, making it even more convenient to hold.

According to the present invention, the following advantages are also exhibited when manufacturing the container.

That is, according to the present invention, when applying and forming the foamable resin on the side wall of the inner container, the degree of foaming of the resin is adjusted to L that allows the use of a conventional curved surface printing machine. Be able to control the degree of insulation. Further, since it is easy to adjust the clearance between the core mold and the cavity mold, the degree of heat insulation effect can be set arbitrarily by this as well.

[Brief explanation of drawings]

FIG. 1 is a front view showing an embodiment of the double container according to the present invention, with a part of the container cut away. Fig. 2 is a plan view of the same as above, Fig. 3 is a side view showing a part of the outer container in longitudinal section, Fig. 4 is a partially longitudinal side view of the inner container, and Fig. 5 shows both the inner and outer containers in a core type. FIG. 6 is a partially longitudinal side view showing a state in which the container is set in a cavity type, FIG. A schematic diagram of a manufacturing apparatus showing an example of mechanically manufacturing the container of the present invention, FIG. 8 is a sectional view showing another embodiment of the double container, and FIG. A perspective view showing the appearance of an ice cream container,
FIG. 10 is a perspective view of an ice cream container with a lid, and FIGS. 11 and 12 are longitudinal sectional views showing a conventional double container. 11: Outer container 12: Small hole 13: Printing part 14
: Inner container 15: Foaming resin 16 Cocoa mold
[7: Cavity type ■9: Lid 20.23: Chieshi conveyor 21: Heating zone 24; Chute 22: Cooling sheet No. 1 Figure 1 Honshu Paper Co., Ltd. Yu-Hi Co., Ltd.

Claims (1)

[Claims] 1. An inner container made of synthetic resin and an outer container made of synthetic resin or whose main material is paper are polymerized almost concentrically, and the outer surface of the inner container and the inner surface of the outer container are polymerized almost concentrically. A double container characterized by having a foamable resin interposed between the containers. 2 An inner container made of a synthetic resin manufactured by a vacuum forming method or a pressure forming method and an outer container made of a synthetic resin or mainly made of paper are polymerized almost concentrically, and the outer surface of the inner container and the outer container A double container which is connected to an inner surface of the inner container through a partially formed foamed resin, and in which an air layer coexists between the inner container and the outer container. 3. The double container according to claim 1 or 2, wherein a small hole communicating with the atmosphere is formed in the side wall and/or bottom wall of the outer container. 4 After forming the inner container by vacuum forming method or pressure forming method, after applying foaming resin liquid partially or completely on the outer surface of the inner container, fitting the inner container into the core mold, and then also applying vacuum forming method. Covering the outside of the inner container with an outer container formed by a molding method or a pressure forming method, or an outer container mainly made of paper, and then heating the container after fitting a cavity mold onto the outer container. A method for manufacturing a double-layered container, characterized in that the resin liquid is foamed and then cooled to remove the container from the mold.