AU2006202552B2 - Bag and method for manufacturing same - Google Patents

Description

S&F Ref: 366499D3

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Kabushiki Kaisha Hosokawa Yoko, of No. 11-5 Nibancho Chiyoda-ku, Tokyo-to, Japan Raizo Kuge Yoshiji Moteki Spruson Ferguson St Martins Tower Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Bag and method for manufacturing same The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c BAG AND METHOD FOR MANUFACTURING SAME The present invention relates to a self-standing bag and to a method for manufacturing such a bag.

As typical examples of a self-standing bag, there are provided a gusset type bag formed of a plastic film material and another bag having a bottom portion specifically worked so as to stand itself. In both the examples, a base plate or sheet is secured in general to the bottom portion of the bag, in order to improve the self-standing characteristics. More specifically, such a bag is composed of a bag body and a folded bottom sheet, in which the bag body and the bottom sheet are heat-sealed together so as to form a heat sealed portion having an oblong shape. The heat sealed portion has two points, and in each of these two points, the bottom sheet and two sheets for forming the bag body are fixed together. The abovedescribed two points are hereinafter referred to as "fixed points".

When the bag having such fixed points is dropped down, a stress caused by the drop of the bag may be concentrated on these fixed points, and hence, the bag may be broken at these fixed points. This problem can be eliminated by forming the bag body with a thin flexible film having a high strength. Such a thin flexible film may degrade the self-standing property of the bag because of a low rigidity of the thin flexible film.

A bag-in-box as a disposal one-way container has widely been used for the transportation and storage of various liquids such as drinks such as mineral water and industrial chemicals.

In such a bag-in-box, a foldable bag or container made of plastic material is used as an inner bag, which is then accommodated in an outer box formed of such as a corrugated board. The inner bag formed of the plastic material has a liquid-tight property, anti-chemical property and gasbarrier property with respect to the liquid contents received therein. The outer box has a rigidity required for the transportation and the storage of the bag-in-box. It is not required for the bag-in-box having such a structure to be recovered in comparison with glass bottles or tin containers, thus providing economical merits. In addition, since the bag-in-box has a foldable structure, the empty bag-in-box can easily be transported and stored, thus providing advantageous effects of reducing distribution costs.

A moulded container formed through a blow-forming process or a flat bag with peripheral edges thereof being heat-sealed together has been used as the inner bag of the above described bag-in-box.

However, a moulded container formed through the blow formation process so as to decrease the thickness of each portion of the moulded container, has in general an insufficient strength. It is accordingly necessary to increase the thickness of each portion of the moulded container. Such a moulded container with the increased thickness therefore does not become easily broken when it is emptied and disposed, thus maintaining its bulky condition, resulting in occurrence of problems of inconvenient transportation, storage and disposal of the empty container. Furthermore, since a mould used for this blow formation is generally expensive, it is hard to satisfy various requirements for the formation in an economical manner. Still furthermore, when contents are received in the bag, it is first required to preliminarily blow air in the empty bag to properly maintain its shape, this being also troublesome. There also arises a problem such that a polyethylene or polypropylene material usually used as a material of a container by means of the blow-forming process has a difficulty in maintaining its barrier property. On the other hand, with the flat bag having C 3 O maintaining its barrier property. On the other hand, with the flat bag having U the peripheral edge heat-sealed, even when the liquid contents are attempted Sto be poured out of the inner bag, part of them remains in the inner bag and 0it is difficult to completely take out the liquid content. In addition, as can be understood from the shape of the flat bag, when the flat bag is accommodated in the corrugated board box, there remain spaces at the Scorner portions of the corrugated board box, and accordingly, various loads CI when stacking up such boxes or dropping them are applied to the corrugated board boxes, thus leading to a problem. Furthermore, the flat bag has a disadvantage in the fact that a large amount of materials used for forming the flat bag is required, and when forming, for example, the flat bag having a capacity of 20 litres, there is required a material having a total area which is larger by about 40 percent than that of a material for forming a cubical bag having the same capacity.

OBJECT OF THE INVENTION It is the object of the present invention to overcome or substantially ameliorate at least one of the above disadvantages, or at least to provide a useful alternative.

SUMMARY OF THE INVENTION The present invention provides a self-standing bag comprising a cylindrical bag body having a pair of opposing flat members for forming front and back surfaces of the bag and a pair of opposing side members each of which is inwardly folded in a gusset shape along a folding line, and a rectangular bottom-forming sheet for sealing a lower open end of the bag body, characterized in that: said bottom-forming sheet is provided with a central folding line extending from one end to the other, a central portion of the bottom-forming sheet having a fold in one direction along the folding line and end portions of the bottom-forming sheet having a fold in the opposite direction along the folding line, each for a length extending between an end of the bottomforming sheet and a reference point distant therefrom by a prescribed distance on said central folding line, each of the end portions of the bottomforming sheet further having a fold along two lines connecting said reference point with two adjacent corners or vicinities thereof of said bottom-forming sheet so as to form ridge lines protruded inwardly of the bag body; and inner surfaces of the bottom-forming sheet being heat sealed onto said lower open end of the bag body so as to form a heat sealed portion along the outer peripheral edge of the bottom-forming sheet, with the central folding lines of the end portions and the folding lines of the side members lying one on the other. There exists therefore no portion on which stress is concentrated in the bottom forming sheet, thus imparting an excellent impact resisting property at the time of dropping of the bag and an excellent self-standing property to the bag.

In another aspect the present invention provides a method for manufacturing a self-standing bag comprising the steps of: forming a cylindrical bag body having lower and upper open ends, said bag body comprising a pair of opposing flat members for forming front and back surfaces of the bag body and a pair of opposing side members each of which is inwardly folded in a gusset shape along a folding line; folding a rectangular bottom-forming sheet in a first direction along a central folding line thereof, folding each of two end portions of the bottomforming sheet, along the central folding line in a direction opposite to the first direction, each for a length extending between an end of the bottomforming sheet and a reference point distant therefrom by a prescribed distance on said central folding line, and then folding each of the end portions along two lines connecting said reference point with two adjacent corners or vicinities thereof of said bottom-forming sheet so as to form ridge lines protruded inwardly of the bag body; inserting said bottom-forming sheet into one of said lower and upper open ends of the bag body so that the central folding lines of the end portions and the folding lines of the side members lie one on the other; and heat-sealing said bottom-forming sheet onto peripheral edge portions of said one of the lower and upper open ends of the bag body.

In a further aspect the invention provides a method for manufacturing a bag for a bag-in-box comprising 'heat-sealing four overlapped vertical portions of vertical edges of each of a pair of flat members and vertical edges of each of a pair of side members, each of which is inwardly folded in a gusset shape along a folding line to form a cylindrical bag body having upper and lower open ends; folding each of a pair of rectangular, opening-sealing sheets in a first direction along a central folding line thereof, folding each of two end portions of each of the pair of opening-sealing sheets, in the opposite direction along its folding line, each for a length extending between an end of the opening-sealing sheet and a reference point distant therefrom by a prescribed distance on said central folding line, and then folding each of the end portions of each of the pair of opening-sealing sheets along two lines connecting said reference point with two adjacent corners or vicinities thereof of the opening-sealing sheet so as to form ridge lines protruded inwardly of the bag body; inserting the pair of opening-sealing sheets into the lower and upper

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0 open ends of the bag body, respectively, so that the central folding lines of the cend portions and the folding lines of the side members lie one on the other, and U heat-sealing the pair of opening-sealing sheets onto peripheral edge portions of the lower and upper open ends of the bag body, respectively.

The preferred embodiment provides a self-standing bag which is (excellent in impact resisting properties at a time of dropping of the bag in addition q to the essential self-standing property.

BRIEF DESCRIPTION OF THE DRAWINGS SIn the accompanying drawings: Fig. 1 is a schematic perspective iew illustrating one end of a bag body; Fig. 2 is a schematic perspective view illustrating one manufacturing mode of a bag body; Fig. 3 is a schematic perspective view illustrating a self-standing bag in an unfolded and standing condition; Fig. 4 is a perspective view illustrating one embodiment of a bottomforming sheet for constituting a self-standing bag; Figs. 5 and 6 are schematic perspective views illustrating sequential steps for manufacturing the bag according to the present invention; Fig. 7 is a schematic perspective view illustrating a step for manufacturing an embodiment of a bag for a bag-in-box according to a method of the present invention; Fig. 8 is a schematic perspective view illustrating one embodiment of an opening-sealing sheet used for manufacturing the bag for a bag-in-box according to the method of the present invention; and Figs. 9 and 10 are schematic perspective views illustrating sequential steps for manufacturing the bag for a bag-in-box according to the method of the present invention.

There is first prepared a cylindrical bag body 10 having upper and lower opening ends as shown in Fig. 1. The cylindrical bag body comprises a pair of opposing flat members 11, 11 for forming the front and back surfaces of the bag and a pair of opposing side members 21, 21. Each of the side members 21, 21 is inwardly folded in a gusset shape along a folding line 23.

The cylindrical bag body 10 is usually made by bonding four pieces of the same material by means of a so-called mitred-bonding method.

Another bonding method described later may however be applied.

In such a bag body 10, each of the side members 21, 21 of the bag body 10 is folded along the folding line 23 so as to form a folding angle 81.

In this embodiment, during manufacture the folding angle is limited under 180 degrees. The side members 21, 21 may however in use be unfolded completely so as to make a folding angle 81 of 180 degrees, Then, a rectangular bottom-forming sheet 30 is prepared as shown in Fig. 4. The bottom-forming sheet 30 is folded along a central folding line 31 thereof. Each of both end portions of the bottom-forming sheet 30, which lies between each of both ends of the bottom-forming sheet 30 and a reference point P or P' distant therefrom by a prescribed distance on the central folding line 31 of the bottom-forming sheet 30, is folded in a direction opposite to the original folding direction of the bottom-forming sheet 30 to form a folding line 31'. Then, each of the both end portions of the bottom-forming sheet 30 is folded along two lines connecting the reference point P or P' with two adjacent corners or vicinities thereof of each of the both end portions of the bottom-forming sheet 30 so as to form ridge lines 32 protruded inwardly of the bag body, to form exposed inner surfaces 3 3a, 33b, 33c, 33d of the bottom-forming sheet 30. In this embodiment, the exposed inner surfaces 33a, 33b, 33c, 33d of the bottom-forming sheet 30 are not fully opened in relation to the shape of the bag body 10, and exposed inner surfaces 33a and 33b, and the exposed inner surfaces 33c and 33d have the respective folding angle 04 which is substantially identical with the above-described folding angle 81 of the side members 21, 21.

Then, the bottom-forming sheet 30 is inserted into at least one of the lower and upper opening ends of the bag body 10 so that the folding lines 31', 31' of the bottom-forming sheet 30 overlap with the folding lines 23, 23 of the side members 21, 21 of the bag body 10, respectively.

Then, as shown in Fig. 5, a hot plate is pressed to the lower peripheral edge portions of the bag body l 0 and the exposed inner surfaces 33a, 33b, 33c, 33d of the bottom-forming sheet 30 to form a heat sealed portion along the lower peripheral edge portions of the bag body 10. The thus formed heat sealed portion is shown in oblique lines in Fig. 6.

Superfluous portions 28 of the bottom-forming sheet 30 may be cut away along a line F, if necessary.

The thus manufactured bag is reversed upside down and then unfolded. Such a bag which is in an unfolded and self-standing condition is shown in Fig. 3.

When contents are received in the thus manufactured self-standing bag 1, the contents are usually poured into the bag 1 through the upper opening end thereof. Then, the upper opening end of the bag 1 is heatsealed. A pouring member may be provided to the upper end portion of the bag 1. Without heat-sealing the upper opening end of the bag 1, the bag 1 may be used as an ordinary bag having the upper opening end for receiving something as shown in Fig. 3.

The cylindrical bag body 10 as shown in Fig. 3 may be formed, as shown in Fig. 2, by bonding overlapped vertical portions of vertical edges of each of a pair of flat members 51, 51 and vertical edges of each of a pair of side members 71, 71 each of which inwardly folded in a gusset shape along a folding line 73, so that the pair of flat members 51, 51 face to each other, and the pair of side members 71, 71 also face to each other. In such a case, material different from that for the side members 71 may be used for forming the flat members 51.

The bag manufactured in accordance with the method of the present invention, in which there exists no portion on which stress is concentrated in the bottom-forming sheet, unlike the conventional bag, is excellent in impact resisting property and self-standig property.

According to another embodiment of the present invention, there is first prepared a cylindrical bag body 10 having upper and lower opening ends as shown in Fig. 7. The cylindrical bag body 10 comprises a pair of opposing flat members 11, 11 and a pair of opposing side members 21, 21.

Each of the side members 21, 21 is inwardly folded in a gusset shape along a folding line 23. Such a cylindrical bag body 10 is prepared by bonding overlapped vertical portions of vertical edges of each of the flat members 42, 42 each having a flat face 11 and vertical edges of each of the side members 62, 62 each having a side face 21, so that the pair of flat members 42, 42 face to each other, and the pair of side members 62, 62 also face to each other. In this embodiment, one of the pair of flat faces 11, 11 is provided with a mouth member 50 through which a liquid is supplied in or taken out from the bag body 10. The mouth member 50 is formed by forming a hole on the one of the flat faces 11, 11, and fitting a mouth piece made of a plastic material, for example, to the above-mentioned hole.

In such a bag body 10, each of the side members 21, 21 of the bag body 10 is folded along the folding line 23 so as to form a folding angle In this embodiment, the folding angle 85 is limited during manufacture to under 180 degrees. The side members 21, 21 may however in use be unfolded completely so as to make a folding angle 85 of 180 degree.

Then, a pair of opening-sealing sheets 35, 35 are prepared as shown in Fig. 8. Each of the opening-sealing sheets 35, 35 is folded along a central folding line 36 thereof. Each of both end portions of the opening-sealing sheet 35, which lies between each of both ends of the opening-sealing sheet and a reference point P or P' distant therefrom by a prescribed distance on the central folding line 36 of the opening-sealing sheet 35, is folded in a direction opposite to the original folding direction of the opening-sealing sheet 35 to form a folding line 36'. Then, each of the both end portions of the opening-sealing sheet 35 is folded along two lines connecting the reference point P or P' with two adjacent corners or vicinities thereof of each of the both end portions of the opening-sealing sheet 35 so as to form ridge lines 37 protruded inwardly of the bag body, to form exposed inner surfaces 38a, 38b, 38c, 38d of the opening-sealing sheet 35. In this embodiment, the exposed inner surfaces 38a, 38b, 38c, 38d of the opening-sealing sheet are not fully opened in relation to the shape of the bag body 10, and the exposed inner surfaces 38a and 38b, and the exposed inner surfaces 38c and 38d have the respective folding angle 86 which is substantially identical with the above-described folding angle 86 of the side members 21, 21.

Then, as shown in Fig. 9, the pair of opening-sealing sheets 35 thus prepared are inserted respectively into the lower and upper opening ends of the bag body 10 so that the folding lines 36', 36' of each of the openingsealing sheets 35 overlap with the folding lines 23, 23 of the side members 21, 21 of the bag body 10, respectively.

Then, a hot plate is pressed to the upper and lower peripheral edge portions of the bag body 10 and the exposed inner surfaces 38a, 38b, 38c, 38d of each of the opening-sealing sheets 35, 35 to form heat sealed portions along the upper and lower peripheral edge portions of the bag body respectively. The thus formed heat sealed portions are shown in the oblique lines in Fig. 10. Superfluous portions 39 of the opening-sealing sheets 35 may be cut away along a line if necessary.

The thus manufactured bag for a bag-in-box is adapted to be accommodated in a corrugated board box to form a bag-in-box. When filling the bag with contents such as mineral water, the mineral water is poured into the bag through the mouth member 50 formed on the flat face 11.

The bag for a bag-in-box, manufactured in accordance with the method of the present invention can be folded in a small size, thus permitting effective transportation, storage and disposal of the bags in an empty condition. In addition, the bag has a rectangular shape in an outward appearance, so that when it is accommodated in a rectangular corrugated board box, there exists substantially no space at inner corner portions of the box, thus improving its strength in stacking them and its impact resisting property in comparison with the corrugated board box itself. Further more, due to this rectangular shape, it is not necessary to preliminarily blow air into 1 8 the bag prior to the filling of the bag with contents, and an improved barrier property is also easily attainable by laminating each of the pair of flat members and each of the pair of side members with a barrier layer.

Claims (3)

1. A self-standing bag comprising a cylindrical bag body having a pair of opposing flat members for forming front and back surfaces of the bag and a pair of opposing side members each of which is inwardly folded in a gusset shape along a folding line, and a rectangular bottom-forming sheet for sealing a lower open end of the bag body, characterized in that: Ssaid bottom-forming sheet is provided with a central folding line extending from one end to the other, a central portion of the bottom-forming sheet having a fold in one direction along the folding line and end portions of the bottom-forming sheet having a fold in the opposite direction along the folding line, each for a length extending between an end of the bottom- forming sheet and a reference point distant therefrom by a prescribed distance on said central folding line, each of the end portions of the bottom- forming sheet further having a fold along two lines connecting said reference point with two adjacent corners or vicinities thereof of said bottom-forming sheet so as to form ridge lines protruded inwardly of the bag body; and inner surfaces of the bottom-forming sheet being heat sealed onto said lower open end of the bag body so as to form a heat sealed portion along .0 the outer peripheral edge of the bottom-forming sheet, with the central folding lines of the end portions and the folding lines of the side members lying one on the other.

2. A method for manufacturing a self-standing bag comprising the steps of: forming a cylindrical bag body having lower and upper open ends, said bag body comprising a pair of opposing flat members for forming front and back surfaces of the bag body and a pair of opposing side members each of which is inwardly folded in a gusset shape along a folding line; folding a rectangular bottom-forming sheet in a first direction along a central folding line thereof, folding each of two end portions of the bottom- forming sheet, along the central folding line in a direction opposite to the first direction, each for a length extending between an end of the bottom- forming sheet and a reference point distant therefrom by a prescribed distance on said central folding line, and then folding each of the end portions along two lines connecting said reference point with two adjacent corners or vicinities thereof of said bottom-forming sheet so as to form ridge lines protruded inwardly of the bag body; inserting said bottom-forming sheet into one of said lower and upper open ends of the bag body so that the central folding lines of the end portions and the folding lines of the side members lie one on the other; and heat-sealing said bottom-forming, sheet onto peripheral edge portions of said one of the lower and upper open' ends of the bag body.

3. A method for manufacturing a bag for a bag-in-box comprising heat- sealing four overlapped vertical portions of vertical edges of each of a pair of flat members and vertical edges of each of a pair of side members, each of which is inwardly folded in a gusset shape along a folding lineto form a cylindrical bag body having upper and lower open ends; folding each of a pair of rectangular, opening-sealing sheets in a first direction along a central folding line thereof, folding each of two end portions of each of the pair of opening-sealing sheets, in the opposite direction along its folding line, each for a length extending between an end of the opening-sealing sheet and a reference point distant therefrom by a prescribed distance on said central folding line, and then folding each of the end portions of each of the pair of opening-sealing sheets along two lines connecting said reference point with two adjacent corners or vicinities thereof of the opening-sealing sheet so as to form ridge lines protruded inwardly of the bag body; inserting the pair of opening-sealing sheets into the lower and upper open ends of the bag body, respectively, so that the central folding lines of the end portions and the folding lines of the side members lie one on the other, and heat-sealing the pair of opening-sealing sheets onto peripheral edge 14 portions of the lower and upper open ends of the bag body, respectively. S4. A bag substantially as described herein with reference to the accompanying drawings. Dated 14 June, 2006 Kabushiki Kaisha Hosokawa Yoko Patent Attorneys for the Applicants/Nominated Persons SPRUSON FERGUSON