A PACKING CONTAINER FOR LIQUID CONTENTS

Abstract: The invention relates to a packing container which is intended for liquid contents and is of the type which comprises a container body with at least one straight side wall (1) and an upper end wall (2) which is joined to the said side wall (1) along a folding line (5) so as to form a relatively sharp transition between the package side (1) and the end wall (2). The said upper end wall (2) is provided with a hole (4) penetrating the package wall which preferably is of triangular shape and which with one of its points reaches up to the lateral edge (5) between the upper end wall (2) of the package and its side wall (1). The hole (4) is covered from the inside by a thin plastic film, and from the hole (4) emanate two diverging perforation lines (6) which extend up to a common crease line (7) arranged in the upper end wall (2). Over the hole (4) and parts of the perforation lines (6) a further cover strip (8) with a thermoplastic coating is provided. The said cover strip (8) is sealed to the inner plastic film exposed in the hole (4) and, at least in the region between the said crease lines (6), to the upper end wall (2).

Description: The present invention relates to a packing container of plastic-coated cardboard intended for liquid contents and of the type which comprises a container body with at least one straight side wall and an upper end wall which is joined to the said side wall along a folding line so as to form a relatively sharp transition between side wall and end wall. It is well-known in packaging technique that non-returnable packages for liquid-filled contents are manufactured by folding of a packing material consisting of plastic-coated cardboard or plastic-coated paper. Such packing containers can be manufactured either from blanks prepared and punched out in advance, which are provided with crease lines facilitating the fold-forming, tearing perforations and holes for pouring openings etc., or else the packages can be manufactured from a web which is rolled off from a magazine roll, and in this case too the packing material is usually provided with crease lines facilitating the fold-forming. The said prefabricated blanks generally are converted to containers in that they are threaded onto a mandrel with the help of which the one end wall of the packing container is formed by folding in the lugs joined to the blank over the end surface of the mandrel whereupon they are fixed by means of heat and pressure in the folded-in position so as to form a tight and firm end wall. After the forming of the said end wall the container is pulled off the mandrel, is filled with the intended contents and is closed by folding together portions of the packing material around the open end of the blank and sealing them to one another in a tight and firm seal in that the plastic layers of the packing material are fused together along the overlapping portions with the help of heat supplied and compression. The packages which are manufactured from a web which is rolled off from a magazine roll are often manufactured in such a manner that the web is converted to a tube by combining the longitudinal edge zones of the web with each other and sealing them to each other, whereupon the tube is filled with the intended contents and divided through repeated transverse seals to form packing units which are separated by means of cuts in the sealing zones. The separated packing units subsequently can be given the desired shape, usually parallelepipedic shape, through folding along the said prepared crease lines facilitating the fold-forming. Packing containers which are manufactured in the above -mentioned manner should be provided appropriately with an opening arrangement so that the contents can be made accessible in a convenient manner to the user of the package. Such a manner which is generally known consists in that a punched-out hole is provided in the package wall, in particular along its upper plane end surface, this hole being covered on the inside of the package wall by a thin plastic film which either constitutes a part of the unbroken inside plastic layer of the package material or a specially applied plastic strip which is sealed around the said hole against the inside layer of the packing material. To make the contents accessible to the consumer of the package the thin plastic film has to be torn up which is done with the help of an outer cover sheet or so-called pull-tab which in general consists of a relatively rigid material, e.g. paper or aluminium foil or laminate thereof and which has a plastic-coated surface. By means of pressure and heat the plastic layer of the cover strip is made to fuse together with the plastic layer which is exposed in the prepared emptying hole, and when the package is to be opened the cover strip is torn off, at which the thin plastic film in the opening hole will be torn up and removed, since it is joined through fusion to the plastic layer of the cover strip. These known opening arrangements in principle functio n well, but sometimes are difficult to realize, so that there is a need for alternative opening arrangements which are simpler to manufacture and cheaper to realize. The present invention is intended to provide an indication of such an opening arrangement whose characteristics are evident from the enclosed claims. An embodiment of the invention will be described in the following with reference to the attached schematic drawing, wherein Fig.1 shows a perspective view of the upper part of a packing container which is manufactured from a packing material prepared for an opening arrangement in accordance with the invention. The packing container shown in Fig. 1, however, is not provided with any outer cover strip. Fig.2 shows how a cover strip is attached and sealed to the package. Fig.3 shows how the package is opened and Fig.4 shows a section through the package along the line of symmetry A-A. The manufacture of the packing material takes place in such a manner that a number of material layers are joined to one another, whereupon the necessary operations in the form of punching of folding lines, realization of perforation etc. together with other processing operations are carried out. Usually the packing material consists of a base layer of paper or cardboard which on the inside as well as on the outside has wholly covering layers of thermoplastic material, preferably polyethylene. In many cases a material with good gas-tightness properties is desired, and in such cases a layer with good gas-tightness, e.g. aluminium foil, is laminated in. As mentioned earlier, the impression of folding lines, the punching of holes and of weakening lines,e.g. perforation lines etc. are all carried out and, of course, the printing of the necessary decoration and text. In the present case it may be appropriate to punch a small, preferably triangular, hole in the laminate before the inner plastic layer is applied, and the necessary perforations or weakenings too canbe realized before the inner plastic layer is applied. After the folding together and forming of the packing material to a packing container the upper part thereof acquires an appearance in accordance with Fig.1. In this Figure the side walls of the packing container are designated 1 and its upper end wall 2. Above the upper end wall 2 extends a sealing fin 3 along which the combined panels forming the end wall are sealed together. The upper end wall 2 is provided with a small triangular hole 4 which extends up to the lateral edge 5 between the end wall 2 and one of the side walls 1 of the packing container. The punched-out hole 4 does not necessarily have to be triangular. In fact, it may be of any shape whatever, but it is important that a part of the hole should extend up to the lateral edge 5. The hole 4 is connected to two perforation lines 6 which extend in divergent manner from the hole 4 towards a crease line 7 foreseen in the end wall 2. As mentioned earlier, the hole 4 is covered from the inside by a thin plastic film which preferably can be constituted of the inside plastic layer of the packing material. This means that the said plastic layer is exposed in the hole 4. As mentioned previously, the package can be provided with a pull-strip 8 which is applied over the hole 4 and parts of the region between the perforation lines 6. The outer cover strip 8 which is shown in Fig.2 is sealed in a region 9 with its inside to the plastic layer exposed in the hole 4 in such a manner that the plastic layers placed against each other are caused to fuse together. Moreover, the inside plastic layer of the cover strip 8 is sealed to the outside of the packing material in the region 10 between the said perforation lines 6.The part of the packing material which is situated between perforation or sealing lines 6, and which borders on the hole 4, advantageously may be in the shape of a tongue stretching out into the hole region 4 and being sealed to the cover strip 8. When the package is to be opened so that the contents of the same can be made accessible,the free pull-tab 11 of the cover strip 8 is pulled upwards and in so doing the inner plastic layer within the hole 4 is torn up. When the cover strip 8 continues to be moved upwards the performation lines or weakening lines will be subjected to stress and break whilst the cover strap 8,thanks to the sealing joint 10, continues to be attached to the part of the upper end wall which is situated between the perforation lines 6. In Fig.3 is shown how the region between the perforation lines or weakening lines is torn up from the packing material belonging to the upper end wall 2, and that a lug 12 of the packing material can be removed by being folded back along the crease line 7 so that an emptying hole 13 is formed. The emptying hole 13 can be partly reclosed in that the lug 12 is folded down again and made to cover the emptying hole 13. The cover strip 8 which is connected to the lug 12 prevents the latter from being fully lowered into and through the emptying hole 13. In Fig.4 is shown a section A-A through the packing material and it is apparent that the smaller hole 4 is situated near the top edge 5 of the side wall 1 and in the hole 4 the outer cover strip 8 is placed lower so as to make contact with the inner plastic layer 14 of the packing material which is fused together with the plastic layer of the cover strip along the region 15. The inside plastic layer of the cover strip or pull-tab is also joined to the outer plastic layer of the upper end wall 2 within the region 10 so that a strong and durable joint shall be formed between the cover strip 8 and the part of the upper end wall 2 which is located between the perforation lines or weakening lines 6. In Fig.4 is also shown how the the crease line 7 is obtained by carrying out a linear indentation in the material, which functions as a pivot for the hingeable lug 12. In thicker packing laminate the crease line 7 may be given a slightly curved shape, preferably with its convex portion facing towards the lug 12. It is the advantage of such an arrangement that the lug 12 on being raised produces stresses in the material which are such that the lug snaps over and remains in its raised position, which can be an advantage since the lug then can be moved out of the way during the pouring operation. In other words, by making the crease line 7 curved, a so-called snap-effect with a stable raised platform is obtained. It has been stated in the description that the weakening lines 6 may consist of a perforation. It is possible, however, within the framework of the concept of the invention to use other types of weakening lines, e.g. such where the material is partly punched through along two parallel cutting lines extending from both sides of the packing material. On tearing up of these the material breaks between the "tops" of the cutting lines. In such a case the inner plastic layer 14, or a specially provided inner cover strip, should be applied after the punching of the insides of the weakening lines, especially if the packages manufactured are intended for sterile goods. It has been found that an opening arrangement in accordance with the invention functions well and is easy and inexpensive to realize. As mentioned earlier, it is not necessary for the hole 4 to be given the shape of a triangle, but other shapes for the said hole, e.g. rhombic, square and even circular, are conceivable. It is a condition though that the hole with some part shall be situated close to the lateral edge 5 and that the perforation lines or weakening lines 6 shall connect to the contour of the hole 4 and extend in divergent manner from each other over the end wall 2.

Claims: 1. A packing container for liquid contents manufactured by means of fold-forming of a packing material of plastic-coated cardboard and of the type which comprises a container body with at least one straight side wall (1) and an upper end wall (2) which is joined to the said side wall (1) along a folding line (5) so as to form a relatively sharp transition between package side (1) and end wall (2),characterized in that a hole (4) is arranged in the said upper end wall (2), which extends up to the said folding line (5) and whose lateral boundary edges are continued in two perforation lines or weakening lines 6 which extend in divergent manner over the upper end wall (2) of the packing container up to a crease line (7) foreseen in the said upper end wall (2), that the said hole (4) is covered from the inside of the package by a thin thermoplastic film (14) which may be constituted of the inner plastic coating of the packing material or of a thermoplastic film specially provided and heat-sealed around the hole (4), that a cover strip (so-called pull-tab) (8) is arranged over the said hole (4) and at least over parts of the region between the perforation lines or weakening lines (6) and which is sealed to the plastic film exposed in the hole (4) and to the outside of the end wall (2) within the region between the perforation lines or weakening lines (6). 2. A packing container in accordance with claim 1, characterized in that the hole (4) is arranged along one of the upper boundary lines (5) between side wall (1) and upper end wall (2). 3. A packing container in accordance with claim 1, characterized in that the crease line (7) which is foreseen in the upper end wall (2) is of curved shape with its convex side facing towards the region (12) between the perforation lines or weakening lines (6).

Inventors: RAUSING, HANS
Applicants: AB TETRA PAK
Application year: 1987
Main classification: B65D5
IPC codes: B65D5