Sealed Container and Process of Manufacture Thereof

This invention relates to a sealed container using as a structural component a container barrel body made of paper. The sealed container is adapted to withstand internal pressure and is suitable for use as a sealed beverage container.

In recent years, from the standpoint of saving resources and the disposal of used containers, a large number of sealed containers have been used for containing fluid contents, such as a composite sealed can using a container barrel body made of paper as a structural component thereof. The sealed composite container of this type can be constructed as shown in FIG. 8, for example. As can be seen, a metallic closure a is hermetically attached to a container barrel body b made of paper by a double curling fastening similar to that used in a conventional metallic container barrel body in manufacturing canned beverages. In this case, the container barrel body made of paper lacks extensibility, unlike the metallic container barrel body, and accordingly when the same is subjected to the double curling fastening, a folded point d of a curling flange thereof and a compressed intermediate part thereof between a seaming wall part e and a chuck wall part f of the metallic closure member a are compressed to become stiff or weakened. When the internal gaseous pressure of the sealed container increases to a high level, the container barrel body made of paper is broken or ruptured at its folded point d and/or at its intermediate part. Consequently the metallic closure member sometimes comes off of the container barrel body.

A main purpose of this invention is to provide a sealed container which uses a container barrel body made of paper as a structural component and yet is sufficiently pressure proof so that it is possible to charge bubbling or sparkling type of beverages therein, such as a carbonated drink or the like.

An additional purpose of this invention is to provide sealed containers which can be packed in close contact with another one.

A further additional purpose of this invention is to provide a sealed container which can be incinerated for disposal.

For achieving the above main purpose, the closure member of this invention comprises a panel and a peripheral wall portion extending vertically downwards from the periphery of and generally perpendicular to the panel. An end surface of the container barrel body is covered with a covering member, and a peripheral surface of the opening portion of the container barrel body is provided with a reinforcing member adhered thereto. The peripheral wall portion of the closure member is mounted on the container barrel and is adhered thereto at a position corresponding to the adhered position of the reinforcing member.

For achieving the above additional purpose, the opening portion of the container barrel body is made smaller in its outer diameter than the remainder part thereof.

For achieving the above further additional purpose, the closure member and the covering member and reinforcing member are made of any material which can be incinerated.

For a better understanding of the present invention, and to show how the same may be put into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

FIG. 1 is a partially sectional view of one embodiment of this invention;

FIG. 2 is an enlarged view of a portion thereof;

FIG. 3 is an enlarged view of a portion of a second embodiment of this invention similar to the view shown in FIG. 2;

FIGS. 4(A)-4(D) are views for explaining a process of manufacturing the example of FIG. 3;

FIG. 5 is an enlarged view of a portion of a third embodiment of this invention similar to the view shown in FIG. 2;

FIGS. 6(A)-6(D) are views for explaining a process of manufacturing the example in FIG. 5;

FIG. 7 is an enlarged view of a portion of a modified example of the embodiment of FIG. 5 similar to the view shown in FIG. 2; and

FIG. 8 is an enlarged sectional view of a portion of a conventional example.

Embodiments of this invention will be explained in detail with reference to the attached drawing as follows.

Referring to FIG. 1 and FIG. 2 showing a first embodiment, a container barrel 1 is made of paper and can be a conventional composite container barrel body which may be of any desired construction, such as spiral, convolute, single wall, etc. The horizontal cross-sectional shape of the barrel body 1 may be any desired shape, such as a circle or a square. Inner and outer surfaces of the container barrel body 1 are applied with a waterproofing agent. As shown in FIG. 2 according to a conventional manner, a basic layer made of paper is applied, on both surfaces with a waterproof covering film formed by an aluminum foil 2 coated with a thermoplastic resin 3, comprising a metallic ion bridge polyolefin series resin (ionomer resin) or a polyolefin series resin including a polar group such as a carboxyl group or the like which has good heat adhering properties for adhering to a metallic material. A closure member 4 is made of a material which can be incinerated such as a material comprising an aluminum foil covered with synthetic resin. In the illustrated example, the container barrel body 1 is provided with two closure members 4, one of which is used as an upper closure member 4a having a pouring hole and the other of which is used as a lower closure member 4b. The respective constructions for joining the upper closure member 4a and the lower closure member 4b to the container barrel body 1 are the same.

Each of the upper and lower closure members 4a and 4b is formed into a cup-like cylinder which comprises a panel 7 and a peripheral wall portion 6 extending vertically downwards from the periphery of panel 7. Each of the closure members 4a and 4b is adaptable to be mounted at the peripheral wall portion thereof on an outer surface of an opening part 1a of the container barrel body 1. Accordingly, when a liquid beverage is contained in the resulting sealed container, an edge, that is, an end surface 1b, of the container barrel body 1 is exposed to the liquid. Therefore, according to this invention, a preventive means is taken such that each of the upper and lower end surfaces 1b, 1b of the container barrel body 1 is covered with a covering member 8 which can be a synthetic resin film.

An opening 5 of the container barrel body 1 is defined at both ends of the body. In addition, the peripheral wall portion 6 of each of the closure members 4a and 4b, mounted on the peripheral outer surfaces of the upper and lower opening portions 1a, 1a of the container barrel body 1, is pressed against the peripheral outer surfaces of opening portions 1a, 1a. In addition, the peripheral wall portion 6 is adhered thereto under pressure so as to obtain a hermetically sealed container. In this case, the container barrel body 1 is made of paper, and sometimes cannot withstand the pressure and force when subjected to the pressing and adhering operations. According to this invention, as a preventive means, an annular reinforcing member 9 is provided, which is made of any material which can be incinerated, such as polyethylene or the like. Annular reinforcing member 9 having a similar annular shape as the opening portion 1a, is adhered to an inner peripheral surface of the opening portion 1a of the container barrel body 1. Thus the peripheral wall portion 6 of each of the upper and lower closure members 4a and 4b is adhered to a part of the outer surface of the opening portion 1a that corresponds to the attached position of the reinforcing member 9. A covering film layer 10 is integrally provided on an inner surface of each of the upper and lower closure members 4a and 4b, and is made of a thermally fusible material such as the foregoing synthetic resin. The film layer 10 is used in adhering the peripheral wall portion 6 to the outer peripheral surface of the opening portion 1a of the container barrel body 1. Thus, because of the structure of the sealed container in accordance with the instant invention, when a carbonated beverage which will generate a high internal gaseous pressure is charged and hermetically enclosed therein, and even whan an expansion force caused by the high internal gaseous pressure is applied to the container barrel body 1, there is no generation of any force for separating the joint portion between the inner surface of the peripheral wall portion 6 and the outer surface of the opening portion 1a of the container barrel body. Rather, a tightening force is generated on the joing portion between the opening portion 1a of the container barrel body 1 and the peripheral wall part 6, according to the diametrical construction of the peripheral wall portion 6 of the expanded closure members 4a and 4b and the diametrical expansion of the opening portion 1a of the container barrel body 1. Thus the joint portion is not broken by the high gaseous pressure, resulting in an improved pressure proofing of the sealed container of this invention.

In the foregoing illustrated example, reinforcing member 9 is provided on the inner peripheral surface of the opening portion 1a of the container barrel body 1, but it can be modified such that the same is provided on the outer peripheral surface thereof.

A process for manufacturing the embodiment of FIGS. 1 and 2 is carried out as follows.

First, an end surface 1b of the opening portion 1a of the container barrel body 1 is covered with a covering member 8. Next, a reinforcing member 9 is adhered to a peripheral inner surface of the opening portion 1a of the container barrel body 1 through heat fusion by heating the covering member 8 and the coated resin 3. Thereafter, the closure member 4a(4b) is mounted on the outer surface of the opening portion 1a of the container barrel body 1. The peripheral wall portion 6 is adhered to the peripheral outer surface of the opening portion 1a at a part thereof corresponding to the adhered position of the reinforcing member 9.

FIG. 3 shows a sectional view of a second embodiment of this invention.

In this embodiment, the covering member 8 for waterproofing each of the upper and lower end surfaces 1b, 1b of the container barrel body 1 and the reinforcing member 9 for reinforcing the opening portion 1b are formed into a single unitary member 12, that is, a covering and reinforcing member 12. In the illustrated example, the member 12 is formed into U-shape for covering the outer peripheral surface, the end surface and the inner peripheral surface of the opening portion 1a of the container barrel body 1. Member 12 is mounted on an opening portion 1a compressed thinner so that an outer surface of an outer part 12a of the mounted member 12 is positioned parallel and level with an outer surface of the remainder portion 1c. Thus, the peripheral wall portion 6 of the closure member 4a or 4b mounted with member 12 on the container barrel body 1 and adhered thereto hardly protrudes from the outer surface of the remainder portion 1c.

A process for manufacturing this second embodiment as shown in FIG. 3 is carried out, for example, as shown in FIGS. 4(A)-4(D). First, the U-shaped covering and reinforcing member 12 is mounted on the opening portion 1a of the container barrel body 1 as shown in FIG. 4(A). In order to facilitate this mounting operation, the covering and reinforcing member 12 is formed so that the lower ends of the two diverged outer portions 12a and inner portions 12b thereof are formed with guide surfaces 12c and 12d. Next, the opening portion 1a and the covering and reinforcing member 12 mounted on the opening portion 1a are pushed into an annular groove 14 made in a forming or pressing die 13. Groove 14 is formed so that the shape thereof conforms with the shape of the opening portion 1a and that the inner diameter of the groove 14 is the same as that of the inner diameter of the innermost surface 12e of the covering and reinforcing member 12 and that the outer diameter of the groove 1 is the same as that of the outer diameter of the container barrel body 1. The forming die 13 is provided with a pair of heating means 15. By the foregoing pushing of the covering and reinforcing member 12 together with the opening portion 1a of the container barrel body 1 into the groove 14 of the forming die 13, the portion 12b of the covering and reinforcing member 12 is immovably held from the inside by the inside part of the die 13 and at the same time the outer portion 12a of the covering and reinforcing member 12 and the opening portion 1a are pressed inward. The opening portion 1a is compressed to become thinner and the outer portion 12a is nestled in a recessed space or room formed outside the compressed thinner opening portion 1a of the container barrel body 1. Thus, an outer surface of the outer portion 12a is positioned parallel and level with the outer surface of the remainder portion 1c of the container barrel body 1. Under this condition the member 12 and the opening portion 1a are adhered together by the two heating means 15, as shown in FIG. 4(B).

Thereafter, as shown in FIG. 4(C), the peripheral wall portion 6 of the closure member 4a (4b) is mounted, through the outer portion 12a, on the outer surface of the opening portion 1a of the container barrel body 1. As shown in FIG. 4(D), the peripheral wall portion 6 of the closure member 4a (4b) is then pressed against the outer portion to be adhered thereto by a pressure application die 17 provided with a heating means 16 applied under pressure to the outer surface of the peripheral wall portion 6.

FIG. 5 shows a sectional view of a third embodiment in which the opening portion 1a of the container barrel body 1 is formed into a reduced-diameter portion 19 and a necked-in portion 18 connecting the reduced-diameter portion 19 and the remainder portion 1c. The outer portion 12a of the covering and reinforcing member 12 is placed on the reduced-diameter portion 19 so that the outer surface of the peripheral wall portion 6 is positioned parallel and level with the outer surface of the remainder portion 1c of the container barrel body 1.

A process of manufacturing the third embodiment of the sealed container, is carried out as shown in FIGS. 6(A)-6(D).

As shown in FIG. 6(A), first, the covering and reinforcing member 12 is mounted on the opening portion 1a of the container barrel body 1. In order to facilitate the foregoing mounting operation, the covering and reinforcing member 12 is arranged so that the lower ends of two lower and parts thereof are provided with the guide surfaces 12c and 12d in the same manner as in FIG. 4. The outermost surface 12f of the covering and reinforcing member 12 is a vertical surface, while the innermost surface 12e thereof is a slant surface that is directed inward from the upper end thereof to the lower end. Thus, the innermost diameter of the member 12 becomes smaller towards the lower end thereof. In other words, the thickness of the inner portion 12b of the member 12 becomes thicker towards the lower end thereof. Next, as shown in FIG. 6(B), a drawn forming of the container barrel body 1 is carried out by using a forming die 20 having an annular groove 21 having a sectional shape formed to conform with the sectional shape of the covering and reinforcing member 12. An outer diameter of the annular groove 21 is the same as that of the container barrel body 1. The forming die 21 comprises two split molds 20a and 20b provided with respective heating means 22. The covering and reinforcing member 12 mounted on the opening portion 1a of container barrel body 1 is pushed into the groove 21 of the forming die 20 so that the opening portion 1a of the container barrel body 1 and the outer portion 12a of the covering and reinforcing member 12 may be pressed inward to form a reduced-diameter covering and reinforcing member and a reduced-diameter opening portion 1a. A necked-in portion 18 is produced due to the guide of the slant innermost surface 12e of member 12 and a slant surface 21a of groove 21. Under this condition, the covering and reinforcing member 12 and the opening portion 1a of the container barrel body 1 are heated by the heating means 22, 22 and thus adhered together through heat fusion of the coated resin 3.

Thereafter, as shown in FIG. 6(C), the peripheral wall portion 6 of the closure member 4a (4b) is mounted, by way of member 12, on the reduced-diameter portion 1a of the container barrel body 1. As shown in FIG. 6(D), a pressure application die 24 provided with a heating means 23 is brought into pressure contact with the peripheral wall portion 6 of the closure member 4a (4b). Under this condition, the peripheral wall portion 6 is heated to adhere to member 12 through heat fusion of the coated resin 10, that is, wall portion 6 is thus adhered to portion 1a of the container barrel body 1.

In each of the foregoing embodiments in FIG. 3 and FIG. 5, the end surface 1b of the opening portion 1a of the container barrel body 1 can be protected from the liquid contents of the sealed container by the covering and reinforcing member 12. Consequently, weakening of the container barrel body 1 caused by penetration of the liquid contents through the end surface 1b thereof can be prevented. In addition, in a case where the sealed container contains a bubbling beverage such as a carbonated drink which generates a high pressure, even when an expansion force of the internal high gaseous pressure is applied to the container barrel body 1 thereof, there is no generation of any force for separating the joint portion between the inner surface of the peripheral wall portion 6 and the outer surface of the opening portion 1a of the container barrel body 1. On the contrary, a tightening force is generated and applied to the joint portion between the opening portion 1a of the container barrel body 1 and the peripheral wall portion 6 of the closure members 4a and 4 b. This tightening force occurs due to contraction of the peripheral wall portion 6 of the expanded closure member 4a (4b) and the diametrical expansion of the opening portion 1a of the container barrel body 1. Thus, the joint portion is not broken by the high gaseous pressure, thus resulting in improved pressure proofing of the sealed container.

Furthermore, since the outer portion 12a of the covering and reinforcing member 12 is provided on the outer surface of the reduced outer diametrical opening portion 1a of the container barrel body 1, the peripheral wall portion 6 of the closure member 4a (4b) does not substantially protrude beyond the outer surface of the container barrel body 1. Consequently, plural sealed containers of this invention can be stacked in substantially close contact with one another.

In the foregoing embodiments in FIG. 3 and FIG. 5, there has been adopted the U-shaped covering and reinforcing member 12 for covering the outer surface, the end surface and the inner surface of the opening portion 1a. However, as can be seen the example in FIG. 1 and FIG. 2, it is sufficient that the same covers the end surface and the inner surface alone or the outer surface alone of the opening portion 1a.

A modified embodiment of such a type is shown in FIG. 7. Namely, the covering and reinforcing member 12 is formed into an L-shape, for covering the end surface and the outer surface alone of the opening portion 1a of the container barrel body 1. The other structural arrangements are the same as the embodiment of FIG. 5. In the foregoing embodiments, the container barrel body 1, the closure member 4a (4b) and the covering and reinforcing member 12 are all made of any material which can be incinerated, so that after use of this invention, the same can be disposed of, simply by incineration. Even if, the closure member 4a (4b) is made of a metallic material such as aluminum, tin free steel, tin-plated sheet or the like used for making a sealed container for a carbonated beverage, the container after use, can still be disosed of by incineration.

It is readily apparent that the above-described meets all of the objects mentioned above and also has the advantage of wide commercial utility. It should be understood that the specific form of the invention hereinabove described is intended to be representative only, as certain modifications within the scope of these teachings will be apparent to those skilled in the art.

Accordingly, reference should be made to the following claims in determining the full scope of the invention.