US3471991A - Method of making filled and sealed packages - Google Patents

Description

1969 H. A. RAUSI NG METHOD OF MAKING FILLED AND SEALED PACKAGES Original Filed Aug. 18, 1965 5 Sheets-Sheet 1 INVENTOR Hans Anders Rausing JWJLM Oct. 14, 1969 H. A. RAUSING METHOD OF MAKING FILLED AND SEALED? PACKAGES Original Filed Aug. 18, 1965 3 Sheets-Sheet 2 INVENmR Hams Anders Rat/sing BY PAM JW X 1 ATTORNEYS 1969 H. A. RAUSING METHOD OF MAKING FILLED AND SEALED PACKAGES Original Filed Aug. 18, 1965 5 Sheets-Sheet I5 INVENTOR Hams Anders Rousing 1 ATTORNEYS United States Patent 3,471,991 METHOD OF MAKING FILLED AND SEALED PACKAGES Hans Anders Rausing, Lund, Sweden, assignor to AB Tetra Pak, Lund, Sweden, a company of Sweden Original application Aug. 18, 1965, Ser. No. 480,632. Divided and this application Feb. 27, 1967, Ser. No. 632,129

llnt. Cl. B6511 41/18 US. Cl. 5327 2 Claims ABSTRACT OF THE DISCLOSURE In the process of the present invention fluent filling material is introduced into a flexible plastic tube that is closed at its lower end, the filled lower end of the tube is introduced into the open upper end of a rigid container, the tube is caused to adhere to the container, the top of the container is folded in to close the upper end thereof and flatten the side walls of the tube together and the tube is then sealed above said container and cut off.

This application is a division of my application Ser. No. 480,632 filed Aug. 18, 1965, now abandoned.

The present invention relates to a filled and closed package of the kind which consists of an outer casing of cardboard or a similar rigid and foldable material, and an inner bag enclosed in the said casing and containing the filling material, said inner bag consisting of a flexible, heat-sealable plastic foil, said outer casing consisting of a tube having a bottom and an upper marginal zone which is folded over the opening of the tube. The invention further relates to a method of manufacturing the said package.

When packaging flowing and liquid filling material the properties of the package and of the packaging material must, of course, be chosen in such a Way that full safety is achieved with regard to the tightness and strength. Packages for liquids have been made for a very long time from a packaging material containing at least two layers, viz. a liquid-proof layer disposed next to the filling material, e.g. polyethylene, and a layer of rigid paper, carton, metal foil or the like, disposed outside of the said liquid-proof layer. In order to simplify the manufacture of packages, the liquid-proof layer and the more rigid backing layer are laminated to each other in advance, whereupon the laminate thus produced is converted into packages.

It is also known to convert packages in which the sealing and mechanically rigidifying functions of the packaging material are produced by means of two separate layers of packaging materials, each of which does not fulfill the demands of mechanical stability or tightness, but which will yield good results when combined. These packages, which consist of a detached inner bag of plastic material and an outer casing of rigid material, in which the said bag has been disposed, have, however, turned out to have certain drawback. Thus, it has turned out that the edge of the bag through which the filling material is poured out is in many cases too flexible, for which reason the jet of filling material becomes difficult to aim, and this of course results in spilling. Furthermore, it has been dilficult to fix the bag to the outer casing in order to prevent the pouring spout of the bag from falling down into the casing when the package is only partly full.

These drawbacks are avoided by using a package according to the invention, which is characterized in that the said inner bag has an outer circumference corresponding to the inner circumference of the casing, and in that at least parts of a bag wall zone enclosing the circum- "ice ference of the bag are adapted to lie snugly against, and adhere to, the inner wall of the casing along at least that part of the marginal zone which is contained in the bellows fold formed by a bellows folding operation.

The method of sealing a package casing by bellows folding is known per se for a plurality of different package types intended for liquid filling material. These package types are not, however, provided with an inner bag of plastic but are sealed e.g. by being impregnated with wax.

The combination of an outer casing with a bellowsfold seal and a detached inner bag has proved highly advantageous, as the inner bag can be squeezed in a simple manner between the fin formed at the bellows folding operation and projecting from the end wall of the container, and because the said fin facilitates the application of a simple but eflicient opening device on the package.

The package according to the invention is consequently characterized in that the marginal zone of the casing is perforated along a continuous or broken line which extends essentially in the circumferential direction of the marginal zone beyond one full marginal zone panel provided with bellows folds and beyond parts of the marginal zone panels contiguous to said panel, and in that the bag is fixed to the interior of the casing within that portion of the marginal zone which contains said line and further in that the package is meant to be opened by parts of the fin being separated from the package casing by tearing the package open along said line provided in the fin, whereby the bag contained in the casing is also torn open along a line behind its seal, and in that the bellows fold exposed by the tearing is folded'outward in order to form a spout having essentially a rhomboidal opening.

The invention relates more specifically to a method for the manufacture of a package of the kind mentioned above and is characterized in that a hose of a flexible, heat-sealable plastic foil, which is sealed at its lower end, has filling material supplied to it at the same time as the lower end of the hose is inserted into a tube of rigid material provided with a bottom, and in that at least parts of that side of the marginal zone which faces the interior of the tube are heated to such a temperature that those surface portions of the plastic hose which have a position corresponding to the said heated zone are caused to melt or become soft to such a degree that adhesion is obtained between the plastic hose and the inner side of the casing along at least parts of the said marginal zone, that the plastic hose, preferably in connection with the closing of the top portion of the tube by bellows folding, is sealed along a narrow sealing zone located outside of the fin formed by the closing of the tube, whereupon the inner bag produced by the sealing operation and enclosed in the casing is separated from the rest of the hose by cuts in the said sealing zone.

Further particulars and advantages of the invention will appear from the appended drawings, showing an embodiment of the invention chosen by way of example, and where FIG. 1 shows a casing consisting of a tube closed in its bottom and provided with a crease line pattern and having a rectangular cross section, in which an inner bag of plastic foil is disposed;

FIG. 2 shows the casing and the inner bag after they have partly had their ends closed by being folded like a bellows;

FIG. 3 shows the closed casing having a sealed inner bag disposed therein;

FIG. 4 shows the finished package;

FIG. 5 shows how a hose having its end sealed is inserted into a casing consisting of a rectangular tube, while the hose has filling material supplied to it;

FIG. 6 shows how the hose lowered into the tube is attached to the marginal zone of the tube wall;

FIG. 7 shows how the casing is sealed and the hose laid flat in the fin formed at the sealing of the casing;

FIG. 8 shows how the hose is sealed and how the inner bag made from the tube and enclosed in the casing is separated from the hose;

FIG. 9 shows how the package is opened by tearing off a portion of the fin along a special opening notch;

FIG. shows the opened package with the pouring spout unfolded.

The package according to the invention is of the type which consists of an outer casing 1 of a relatively rigid material, e.g. carton, and an inner bag 2 of plastic foil. The said casing 1 consists of a tube of a rectangular cross section having a bottom and being provided with a crease line pattern facilitating the closing of the tube by folding, said pattern containing two crease lines 3 and 4 enclosing the circumference of the tube, which lines divide each of the side walls of the tube into three panels, viz. one marginal zone panel 5, one end wall panel 6 and one side wall panel 7. Two of the opposite sides of the tube are in addition provided with three crease lines forming an inverted Y having the two downwardly and outwardly directed prongs 8 and 9 extending from the center of the crease line 3 to the corners between the crease line 4 and the lateral marginal lines 11 and 12 of the tube, and the upwardly directed prong 10 extending from the common point of the crease lines 8 and 9 to the central point normal to the opening margin 13 of the tube. The bag 2 enclosed in the casing 1 is attached to the inside of the tube along an adhesion zone 14 extending around the inside of the marginal zone 5.

The outer circumference of the bag 2 should essentially concide with the inner circumference of the tube 1 so that the bag wall is well stretched without folds along the adhesion zone 14 extending around the inside of the tube. In the marginal zone 5 of the tube there is further disposed a slot 15 perforating the tube wall. This slot may either be a continuous slot or may have regularly recurring imporforate portions having for their purpose to hold together the margins of the slot 15 at the fixing of the inner bag 2. The slot 15 extends along one full marginal zone 5 between the lateral marginal lines 11 and 12 and extends a certain distance in the marginal zone 5 at the contiguous tube sides corresponding to the distance between the crease line 10 and the side wall margins 11 and 12, respectively. Furthermore, the slot should be disposed in such way that the adhesion zone 14 will cover the margins of the slot, which will be held together by the I imperforate bag wall fixed along the adhesion zone.

FIGS. 2 and 3, which are provided with the same reference numerals as FIG. 1, show the construction and the fold pattern of a package of the present kind. The marginal zone 5 is consequently bellows folded with the points 16 of the bellows folds laid along the crease lines 10. Furthermore, the opposite rectangular end wall panels 6 are folded in over the tube, at the same time as the remaining two end wall panels are folded along the crease lines 8 and 9 so as to form three triangular flaps, of which those disposed on both sides of the central flap defined by the crease lines 8, 9 and 4 are folded in over the said central flap. The casing 1 shown in FIG. 3 is provided with an essentially plane end wall surface and a fin 21 projecting from the end wall and formed by the bellows folded marginal zone 5. However, it is also possible to produce a ridge-shaped end wall panel by reducing the angle between the crease lines 8 and 9, which has been chosen about 90 in the embodiment shown here, the said angle giving a plane end wall surface.

At the closing of the tube end not only the marginal zone 5 of the tube but also the bag 2 fixed to the tube will be bellows folded and fixed in the folded state due to the portion of the bag 2 which projects from the fin 21 of the casing being sealed with a joint 17 extending essentially in parallel to the margin of the fin. In order that the points 16 of the folds formed at the bellows folding operation may not meet when the end of the package is closed, those panels in the marginal zone 5 which contain the crease lines 10 facilitating the bellows folding must be shorter in the circumferential direction or at any rate not longer than the marginal zone panels 5 which are not meant to be folded.

As it is not desirable that the fin 21 shown in FIG. 3 should project from the package wall, it is advisable to fold the fin into contact with the end wall panels 6. This produces the package shown in FIG. 4 and having an essentially plane upper end wall.

In order that the fin 21 may be retained in the foldeddown position, it has to be fixed to the end wall panel 6. This fixing may, of course, be carried out as a gluing operation with conventional glues, but considering the fact that the packages are to be made in packaging machines of large capacity, it is important that the joint which connects the fin and the end wall panel 6 will quickly obtain such a strength that the fin will be retained in the position occupied at the folding operation, without the aid of mechanical support from the outside. In order to permit quick fixing of the end wall panel of the casing 1 and the fin, the casing may be provided with an outer coating of thermopalstic material, e.g. polyethylene, which has the quality, when being heat-sealed against another polyethylene surface, of producing a sealing joint which is very strong and becomes stabilized very quickly. The polyethylene coating is besides liquid-proof and consequently protects the package casing effectively against exterior moisture.

The package described above is produced in such a way that the casing 1 is prefabricated by forming a plane material web into a tube having rectangular cross-section and providing it with a bottom of an arbitrary construction. Furthermore, a crease line pattern of the appearance described above is made in the tube wall. The tube thus produced, which is meant to form the casing 1 of the package, is placed under an annular extrusion nozzle, through which a hose 20 of thin heat-scalable plastic foil is extruded. At its lower end the extruded hose 20 is sealed with a sealing joint 17 extending essentially at right angles to the longitudinal axis of the hose 20. The extruded hose 20 has filling material supplied to it through a filling pipe 19 disposed concentrically of the extrusion nozzle and is simultaneously inserted into the tubular casing 1 with the aid of the weight of the filling material itself. As the insertion of the hose 20 into the casing 1 begins before it has received the intended quantity of filling material, there are no difiiculties in inserting the hose into the casing. It is true that the hose does not of itself assume the same cross-section as the casing 1, but since at the insertion it has only received a relatively small quantity of filling material, the lower portion of the hose 20 assumes the shape of the tube opening and will automatically obtain the same cross-section as the casing 1, since the outer circumference of the hose 20 essentially corresponds to the inner circumference of the casing 1. When the hose 20 has been completely lowered into the casing 1 with the aid of the weight of the filling material itself, such a large additional quantity of filling material is supplied that the pressure of the filling material will press the hose against the inner wall of the casing. Prior to or simultaneously with the final filling operation an adhesion zone 14 on the marginal zone 5 closing in the circumferential direction of the tube has become heated to such a degree that the hose 20 pressed against the said Zone 14 is caused to melt along part of its surface and thus adhere to the inside of the casing along the said zone. In order to secure good contact between the heated adhesion zone 14 and the hose 20 it is advisable, for instance by supplying air thereto, to keep the hose 20 under an interior pressure above atmospheric of between 0.001 (0.0147 p.s.i.) and 1 atmosphere (14.70 p.s.i.),

(preferably 0.01 to 0.1 atmosphere) (0.147 to 1.47 p.s.i.). The zone between the hose 20 and the casing 1 intended to adhere to the inside of the marginal zone 5 may either be heated only after the hose 20 has been completely inserted into the casing 1, or may be preheated. In the latter case the hose 20 at the insertion into the casing 1 must, of course, be prevented from coming into contact with the heated adhesion zone 14, as the hose 20 would otherwise be adhered to the zone 14 without being first completely inserted into the casing 1.

In order to prevent surface contact between the hose wall and the heated zone 14 a screen may be disposed over the area 14, while the hose 20 is inserted into the casing 1. When the hose 20 is completely inserted, the screen is removed and the bag wall will come into contact with and be fixed to the heated zone 14. The adhesion zone 14 in the marginal zone 5 of the tube may preferably be heated by hot air being blown against the inside of the tube or by heated jaws being pressed against the outside of the tube. Of course, it is also possible to defer the supply of heat to the adhesion zone 14 until the hose 20 has been completely inserted into the casing 1. In this case, however, the heat must be supplied by outer means and the heat must be transported through the tube wall, which results in a relatively long heating time and consequently a longer total time for producing the package.

When the hose 20 is inserted into the casing 1 and is fixed to the casing along the adhesion zone 14 and filled with the intended quantity of filling material, the upper end wall of the casing 1 is closed by folding the end wall panels 5 and the marginal zone panels 6 like a bellows in over the cross-section of the tube forming the casing 1. This closing operation is shown in FIG. 7 and is carried out by means of conventional folding means. When the end wall panels 6 are folded down into the same plane and the marginal zone panels 5 are united so as to form a fin 21, the bellows folded hose 20 is sealed along a sealing line 17, whereupon the bag 2 enclosed in the casing 1 and formed by the lower portion of the hose 20 is separated from the hose 20 by a cut through the sealing zone 17, as illustrated in FIG. 8. After the fin 21 has been folded inwards towards the plane end wall 6 and has been fixed to the said wall by means of a heat-sealing union which is easy to open, the package has the appearance shown in FIG. 4 and is consequently ready for distribution.

The bellows fold 16 which, due to the resilient properties of the packaging material, has a natural tendency to move may, of course, be fixed in the flattened condition by gluing together or heat-sealing those outer portions of the fin 21 which face each other in the bellows fold 16. However, it should be seen to in that case that the sealed or glued area is thawed in that portion only of the fin 21 which is located over the opening slot 15, or else the opening of the package cannot be unfolded in a normal way.

The package is opened by breaking the union between the fin 21 and the end wall 6 and raising the fin so that it projects from the end wall 6 of the package. The opening slot 15 disposed in the fin of the package is torn open in the way shown in FIG. 9, the wall of the inner bag 2 disposed in the casing being perforated along the fin 21 where the bag 2 and the marginal zone wall 5 are united in a sealing joint 14 extending around the marginal zone 5 of the tubular casing 1.

Since the bag 2 is torn open behind the sealing zone 17, the filling material can be reached through the slot 15 formed at the tearing operation. However, the area of the slot is too small to permit the slot to function as a pouring opening, and it is therefore necessary to widen the slot. FIG. shows how the bellows fold 16 exposed when the fin 21 is torn open along the opening notch can be unfolded so as to form an essentially rhomboidal opening 22 through which the filling material can be poured out. In order to facilitate the forming of the emptying spout 22 at the unfolding of the bellows fold 16, it is advantageous to dispose in each of the rectangular end wall panels 6 a crease line 23 extending from the corner between the lateral marginal line 12 contiguous to the opening spout 22 and the crease line 3 separating the end wall zone 6 and the side wall panel 7 to the ends of the slot 15 disposed in the fin 21 and intended to serve as an opening notch.

That portion of the fin 21 which has been separated from the casing 1 by being torn along the cut 15 may either be folded aside so that it will not project over the rhomboidal opening 22, or may be torn away completely.

The package described above is also suitable for use as is. package for sterilized products, such as sterilized milk, since the wall material of the bag 2 is impervious to bacteria and since the casing provides good mechanical protection against such mechanical action on the bag 2 as may cause micro-leakages, thus jeopardizing the bacteria-proof qualities of the package, without imparing its liquid-proof qualities. The manner in which the package is manufactured and filled is also advantageous for use at the packaging of sterile liquid products.

When a sterile product is to be packed, certain steps have to be taken. Thus, the extrusion hose 20 first has to be sterilized. This is preferably carried out in such way that the hose is sealed along its lower end and so that the cavity located between the extrusion nozzle and the sealed end is exposed to the action of hot steam or some other sterilizing medium. After the said cavity has become well sterilized, sterility in the interior of the hose is automatically maintained by the extrusion temperature of the hose being so high that all bacteria and microorganisms existing in the plastic mass are destroyed and so that no reinfection of the hose 20 can take place, since its lower end is always sealed. The sterile product is supplied to the internally sterile hose 20 through the filling pipe 19, which must of course also be sterilized before filling operation can begin. After the internally sterilized hose 20 has been inserted into the casing 1, has been filled with sterile filling material and has been sealed with a bacteria-proof seal 17, the filling material is packaged in a bacteria-proof package, and the sterile filling material is not on any occasion during the packaging operation exposed to the risk of coming into contact with a surface or atmosphere contaminated by bacteria.

It is evident that this method has considerable advantages in comparison with other methods, according to which the packaging operation has to be carried out in special sterile chambers, where it is difficult to guarantee absolute sterility.

The embodiments shown and described here of both the package and the method for its manufacture have proved highly advantageous from a functional as well as an economical viewpoint. Of course, it is possible to modify both the package and the method for its manufacture within the scope of the invention. Thus, it is possible but neither practical nor necessary to fix the inner bag along larger portions of the inner wall of the package casing than the adhesion zone 14 shown in the embodiment. Furthermore, it is not, of course, necessary to fold the end wall 6 so far in over the cross-section of the casing that a plane end wall is formed.

The reason Why the inner bag 2 is sealed along a sealing zone 17, which is located outside of the fin 21 folded like a bellows, is entirely of a practical nature, it being easier to create an efiicient seal between plastic layers alone than between plastic seals which are surrounded on both sides by a heat-insulating carton layer. Of course, it is entirely possible to seal the bag 2 along a sealing zone which is located in the fin 21, but since this method has certain disadvantages, it has not been utilized in the embodiment described.

Sometimes it will be difficult to heat the tube wall in such a way that the hose will adhere to the tube wall without destroying the hose wall which easily can be melted through, if the hose wall is too thin. Therefore it might be necessary to adhere the hose to the inside of the tube wall by means of glue. As it will be almost impossible to use ordinary glue for this purpose, a hot melt glue has been used which becomes activated by means of heat. Owing to the fact that the hot melt glue is activated by heat the above mentioned means arranged for adhering the hose to the tube wall can be used even if the adhering is obtained by means of hot melt glue, but of course, the degree of heating must be adapted to the qualities of the material.

Iclaim:

1. A method of making a filled and sealed package having an outer casing of rigid and foldable material and an inner bag enclosed in said casing and containing the filling material, said inner bag consisting of a flexible, heat sealable plastic foil, which comprises forming a vertically disposed hose closed at its lower end of said plastic foil, supplying a portion of the filling material required to fill said bag in fluent form to said hose, inserting the lower end of said hose into said casing having a tubular side wall, a bottom wall and an open top by relative vertical movement of at least one of said hose and said casing, completing the filling of said hose up to the capacity of said bag, contacting the walls of said casing with heated jaws in a zone near the upper end thereof prior to insertion of said hose, sealing the heated zone of said casing to the upper end of said hose after insertion of the latter, closing the open end of said casing by bellows folding and thereby forming a fin extending upwardly from the closed top of said casing, said hose being flattened between the walls of the fin, sealing said hose along a narrow band above said fin, and severing said hose within said narrow band.

2. The method as defined in claim 1 and which includes the further step of screening said hose from contact with said heated zone of said casing while being inserted therein.

References Cited UNITED STATES PATENTS 2,872,763 2/1959 Meissner.

FOREIGN PATENTS 714,414 7/1965 Canada.

THERON E. CONDON, Primary Examiner E. F. DESMOND, Assistant Examiner

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