An opening arrangement for a packing container

Abstract: The present invention relates to an opening arrangement for packaging containers (1) of single use disposable type, manufactured from a laminate material (4). The opening arrangement comprises an opening strip (10) inlaid in the one transverse seal fin (3) of the packaging container (1). The opening strip (10) extends from a point (11) which forms the pouring spout of the packaging container, outside the packaging container (1) in the longitudinal sealing seam (2). The opening strip (10) is, at least on its one side, coated with a non thermosealable region (13) which is placed where the opening strip (10) departs from the transverse sealing fin (3). The non thermosealable region (13) merges into a hatched region (14) on that part of the opening strip (10) which lies outside the packaging container (1).

Description: TECHNICAL FIELD The present invention relates to an opening arrangement in a packaging container produced from a plastic-coated packaging material and being of the type which is formed into a tube with a longitudinal sealing seam, the container displaying a sealing fin extending transversely over one container wall, in which sealing fin opposing packaging material layers are united with one another, the opening arrangement comprising an opening strip inlaid in the sealing fin and extending through the longitudinal sealing seam of the packaging container to the outside of the packaging container. BACKGROUND ART Within the packaging industry, use is often made of a packaging material with a core of paper or cardboard laminated with thermoplastic and possibly a metal foil, e.g. aluminum foil, for the manufacture of single-use disposable packages or cartons for milk, juice or the like. The package is formed from a continuous material web or a material sheet. From, for example, a web, parallelepipedic packages are produced in that the web is first formed into a tube by the longitudinal edges of the web being united with one another in a longitudinal overlap seam or joint. The tube is filled with its intended contents and divided into closed packaging units by repeated transverse seals of the tube. In such instance, cushion-like packaging blanks are obtained which are thereafter finally formed into parallelepipedic packages. In order, in a simple manner, to gain access to the contents of the package, some form of opening arrangement is required. In this instance, it is previously known in the art to inlay a tearing strip into one of the transverse sealing seams. Such an opening arrangement is, for example, described in Swedish Patent Application No. S-9002640-2 (EP-A-0471 274). By providing the packaging container with such an opening strip, there will be obtained an opening arrangement which, with a simple manual operation, opens the package and at the same time forms a part of the upper portion of the package into a pouring spout. Such opening strips are often manufactured from a laminated plastic material in which one of the layers is cohesively broken on opening so that a part of the opening strip is left in place on the inside of the packaging material. This is to prevent the packaging material from delaminating so that the inner layer of paper or cardboard is exposed to the liquid contents. However, it has proved that in the initial stage of the opening procedure, a certain delamination of the packaging material may take place with the above-described type of tearing strip. OBJECTS OF THE INVENTION One object of the present invention is to avoid such delamination of the packaging material taking place in the initial stage of the tearing-off of the opening strip. A further object of the present invention is to obtain a distinct and easily identifiable marking on the outer portion of the opening strip. SOLUTION These and other objects have been attained according to the present invention in that the opening arrangement of the type described by way of introduction has been given the characterizing features of claim 1. Preferred embodiments of the present invention have further been given the characterizing features as set forth in the appended subclaims. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS One preferred embodiment of the arrangement according to the present invention will now be described in greater detail hereinbelow, with particular reference to the accompanying Drawings. In the accompanying Drawings: Fig.1 shows a portion of the packaging material with an inlaid opening strip; Fig. 2 shows the upper portion of an unopened packaging container with an opening arrangement according to the present invention; Fig. 3 shows a cross section of the sealing fin of an unopened packaging container; Fig. 4 shows the packaging container in the process of being opened; and Fig. 5 shows a cross section of a sealing fin of the packaging container during the opening operation. DESCRIPTION OF PREFERRED EMBODIMENT A packaging container 1, of the type which is formed into a tube with a longitudinal overlap joint or seam 2 and is thereafter cut off into individual packages by means of transverse seals 3, can be manufactured from a continuous material web or a punched-out material sheet, a so-called blank. The packaging material 4 consists of a core 5 of paper or cardboard to which is laminated different layers of thermoplastic 6 and 7, and possibly a metal foil, preferably aluminum foil. Fig. 1 shows a part of a packaging material 4 with crease lines 8 with the aid of which the package 1 is, in its final forming, folded into a parallelepipedic packaging container 1. In that region 9 where the transverse sealing takes place and which will form the upper sealing fin 3 of the packaging container 1, there is inlaid an opening strip 10. The opening strip 10 extends from that point 11 on the packaging material 4 where the packaging material 4 is folded in its transverse joint sealing 3. This point 11 will, at a later stage on an opened package 1, constitute the outermost point 11 of the pouring spout. From this point 11, the opening strip 10 extends outside the packaging material 4 whose outer defining line 12 will constitute the outer point of the longitudinal sealing joint or seam 2 of the package. At the point 12 where the opening strip 10 is no longer in contact with the packaging material 4, there is shown, in Fig. 1, a region 13 surrounding on both sides the outer defining edge 12 of the material web and constituting that region 13 which is coated with a non thermosealable layer. This non thermosealable layer may consist of some form of printing ink of the type which is not heat sealable to polyethylene and which, moreover, is resistant to the sterile liquid used in the filling machine. At the marked region 13 of the opening strip 10 surrounding on both sides the edge line 12 of the packaging material 4, this non thermosealable layer is printed fully covering one side of the opening strip 10. The other side of the strip 10 may also be coated with a non thermosealable layer. However, experiments have demonstrated that a good opening of the package 1 will be obtained with only one side of the strip 10 coated. On application to the packaging material 4, the opening strip 10 is turned so that the non thermosealable layer faces towards the inside layer 7 of the packaging material 4. The region 13 coated with the non thermosealable layer constitutes approximately 4 - 6 mm of the opening strip 10, with a certain tolerance for application such that this region 13 always extends 2 - 3 mm on either side of the outermost edge 12 of the packaging material 4. By employing a non thermosealable layer consisting of a printing ink in a colour which differs from that of the remainder of the packaging container 1, it is possible, by hatching the remaining portion 14 of the projecting opening strip 10, to obtain a colour marking which indicates where the opening strip 10 is located. If use is made of a printing ink colour which differs from that of the non thermosealable layer, a degree of hatching should be employed which is sufficient to make for easy identification of the opening strip 10. Nor should the hatching be denser than permits the opening strip 10 on the exteriorly finished package 1 to be fixed to the outer side of the package 1. A suitable degree of hatching is 20 to 70 % of the surface. Fig. 2 shows the upper portion 15 of a ready-formed package 1 provided with an opening arrangement according to the invention. On the packaging container 1 in Fig. 2, the one gable flap 16 which is to form a pouring spout is raised from its lowered distribution position. The opening strip 10 is shown against the upper side 15 of the packaging container 1. The opening strip 10 extends out through that longitudinal sealing joint or seam 2 of the package 1 in which begins the region 13 coated with the non thermosealable layer, and thereafter extends out outside the packaging container 1. A distance outside the longitudinal sealing seam 2, that region 14 of the opening strip 10 which is hatched begins. Given that the degree of hatching is such that a certain sealing is still possible, the opening strip 10 is fixed against the upper side 15 of the packaging container 1 by means of a point seal 17 so as to avoid the risk that the opening strip 10 catches in other packages 1 on distribution and handling. Fig. 3 shows a cross section of the upper sealing fin 3 of the packaging container 1, and how the opening strip 10 can be built-up. Outer layers 19 of sealable plastic material, preferably polyethylene, are laminated about an inner layer 18 of a tensile strength material, preferably polyester. Between the inner layer 18 and the outer adhesion layers 19, there is an intermediate layer 20 of a material of such a nature that the adhesive bonding force between all material layers included in the opening strip 10 and with the outer layers 19 of the opening strip and the inner thermoplastic layer 17 of the packaging material is considerably greater than the internally cohesive bonding force in the intermediate layer 20 itself. Fig. 4 shows the packaging container 1 in the process of being opened, the opening strip 10 is removed from its point seal 17 on the upper side 15 of the packaging container 1 and is pulled upwards. The opening strip 10 is then cohesively broken in the layer 20 as shown in Fig. 5. Since the opening strip 10 in the initial stage of the opening operation is coated, in a region 13, with a non thermosealable layer which extends in over the edge 12 of the packaging material 4, the opening strip 10 cannot, on tearing-off, become caught in the edge 12 of the packaging material 4 and thereby delaminate the packaging material 4. At the same time as the opening strip 10 is pulled upwards, there will also be obtained a forming of the pouring spout which makes the liquid contents accessible. By providing the sealing fin 3 of the packaging material 4 with prefabricated perforations, the pouring spout may be formed easily and distinctly so that, after tearing-off of the opening strip 10, it is possible to pour the contents direct from the package. As will have been apparent from the above description, the present invention realises an opening arrangement with an opening strip 10 inlaid in the upper sealing fin 3 of the packaging container 1, this strip not suffering from the problems and drawbacks inherent in prior art opening strips. At the same time, there will be obtained a colour indication which directly shows the position of the opening strip 10 and which thereby facilitates opening of the package 1. The present invention should not be considered as restricted to that described above and shown on the Drawings, many modifications being conceivable without departing from the scope of the appended Claims.

Claims: An opening arrangement in a packaging container (1) produced from a plastic-coated packaging material (4) and being of the type which is formed into a tube with a longitudinal sealing seam (2), the container displaying a sealing fin (3) extending transversely over one container wall (15), in which sealing fin opposing packaging material layers (7) are united with one another, the opening arrangement comprising an opening strip (10) inlaid in the sealing fin (3) and extending through the longitudinal sealing seam (2) of the packaging container (1) to the outside of the packaging container (1), characterized in that a part or region (13) of the opening strip (10) on at least one side is coated with a non thermosealable layer which region (13) extends from the inside of the longitudinal sealing seam (2) to the outside of the packaging container (1). The opening arrangement as claimed in claim 1, characterized in that the non thermosealable region (13) is located on that side of the opening strip (10) which is turned to face towards the inside layer (7) of the longitudinal sealing seam (2). The opening arrangement as claimed in in claim 1 or 2, characterized in that the non thermosealable region (13) extends 2-3 mm on either side of the outermost edge (12) of the packaging material (4). The opening arrangement as claimed in one of the preceding claims, characterized in that the non thermosealable region (13) extending outside the packaging container (1) merges into a hatched region (14). The opening arrangement as claimed in claim 4, characterized in that the degree of hatching of the hatched region (14) is between 20 and 70 per cent. The opening arrangement as claimed in one of the preceding claims, characterized in that the opening strip (10) consists of a laminate of the type which on opening of the packaging container (1) is broken cohesively in at least one intermediate layer (20). The opening arrangement as claimed in one of the preceding claims, characterized in that said non thermosealable region (13) comprises a printing ink which is resistant to sterile liquid used in the filling machine.

Inventors: JOENSSON TOMMY, LINDSJOE ULF, JOENSSON, TOMMY, LINDSJOE, ULF, JÖNSSON, Tommy, Lindsjö, Ulf
Applicants: TETRA LAVAL HOLDINGS & FINANCE, TETRA LAVAL HOLDINGS & FINANCE SA
Application year: 1993
Main classification: B65D5
IPC codes: B65D5