Patent Publication Number: US-2022227517-A1

Title: A sealing device, and a packaging container

Description:
TECHNICAL FIELD 
     The invention relates to a sealing device for providing transversal seals to a packaging material in order to form individual packaging containers. The present invention also relates to a packaging machine, a packaging material, and a packaging container. 
     BACKGROUND ART 
     The Tetra Classic® Aseptic carton packaging container has been commercially available for many years. The tetrahedron shape was developed already in the 1950s and the type of packaging container has proven to be very suitable for various food products such as juice drinks, milk, spreadable cheese, ice-lollies, etc. The general technical packaging concept is based on forming a tube by sealing two opposite longitudinal ends of a flat web of packaging material to each other, filling the tube with the content to be packaged, and providing upper and bottom transversal seals to the tube in order to seal individual packaging containers. The tetrahedron shape is obtained by providing the upper and bottom transversal seals approximately perpendicular to each other. During the transversal sealing, or immediately after, the downstream packaging container is separated from the upstream tube by a transversal cut close to the transversal seal. 
     Different opening solutions can be implemented for the tetrahedron package, such as straw holes, pull tabs, etc. For ice-lollies, the tetrahedron shaped package is provided with a transversal perforation extending across the entire, or parts, of the packaging container width. By gripping and pulling the transversal seal fin adjacent to the perforation, the consumer can remove the entire transversal seal and thereby gain access to the frozen content. In order to function properly, the perforation must not be located at the seal. This means that frozen product can appear at the region of the perforation. 
     If this is the case, there is a general problem to easily open the perforation since the frozen product will hinder both tear initiation and tear continuation. In order to avoid this problem, it has been suggested to move the position of the perforation closer to the transversal seal. However, such measures will provide additional disadvantages as it will reduce the width of the flat sealed fin, thereby reducing the ability to firmly grip and apply the needed force to open the packaging container. Yet further, as the perforation is located in close proximity to the transition between the transversal seal and the main packaging container body, there is also an increased risk for perforation related integrity issues. 
     There is thus a need for an improved packaging container of the above-mentioned tetrahedron shape, reducing the risk for packaged content at the area of the perforation, and without introducing the above-mentioned disadvantages. 
     SUMMARY 
     It is an object of the invention to at least partly overcome one or more of the above-identified limitations of the prior art. In particular, it is an object to reduce the risk for packaged content to appear at the area of the perforation used to open the packaging container. 
     To solve these objects, a sealing device for forming a transversal seal to a tetrahedral packaging container is provided. The sealing device comprises a sealing element and an imprint ruler arranged at a longitudinal distance from the sealing element, wherein the sealing element is configured to provide a top transversal seal to a packaging container while the imprint ruler is configured to provide a transversal imprint to the same packaging container. 
     The sealing device may further comprise a flattening section arranged between the sealing element and the imprint ruler. 
     The distance between the sealing element and the imprint ruler may be in the range of 5-25 mm, preferably 10-20 mm. 
     The sealing element may be configured to provide a top transversal seal to a packaging container, and wherein the imprint ruler is configured to provide a transversal imprint to the same packaging container. 
     The imprint ruler may be configured to provide the imprint above a perforation of the associated packaging container, such that the perforation is arranged between the imprint and the top transversal seal. 
     According to a second aspect, a packaging container is provided. The packaging container comprises a tetrahedral shape extending between a top transversal seal and a bottom transversal seal, and a perforation for facilitating opening of the packaging container, characterized by a transversal imprint arranged above the perforation such that the perforation is arranged between the imprint and the top transversal seal. 
     The distance between the imprint and the end of the bottom transversal seal may be in the range of 10-30 mm, such as in the range of 15-25 mm. 
     The packaging container may enclose a frozen food product, such as an ice lolly. 
     According to a third aspect, a packaging material is provided. The packaging material is configured to form a packaging container according to the second aspect. The packaging material comprises a top transversal seal area, a bottom transversal seal area, a plurality of folding lines, and a transversal perforation, wherein the perforation is arranged at a distance, and in between the top transversal seal area and the folding lines. 
     The distance between the top transversal seal area and the folding lines may be approximately 5-25 mm, wherein the perforation is arranged therebetween. 
     Still other objectives, features, aspects and advantages of the invention will appear from the following detailed description as well as from the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example embodiments of the invention will now be described with reference to the accompanying schematic drawings, in which 
         FIG. 1  is an isometric view of a prior art packaging container; 
         FIG. 2  is an isometric view of a packaging container according to an embodiment of the present invention; 
         FIG. 3  is a cross-sectional view of a sealing device according to an embodiment of the present invention for manufacturing of a packaging container as shown in  FIG. 2 ; 
         FIG. 4  is a planar view of a packaging material for producing a packaging container as shown in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIG. 1  a prior art packaging container  1  is illustrated. The packaging container  1  is typically produced such that a web of a packaging laminate material is first formed into a tube by both longitudinal edges of the web being united to one another in a liquid-tight overlap joint  2 . The tube is preferably aseptically filled with its desired content, e.g. flavored water, and subsequently divided by repeated transversal thermal seals  3 ,  4  alternatingly 90° transversely in relation to one another. Consequently, individual tetrahedral packaging units  1  (which are separated from one another by a cutting mechanism) are formed. 
     Immediately inside one of the seals  3  a perforation  5  is provided. The perforation is as long as the seal  3 , or possibly shorter than the seal  3 , whereby opening of the packaging container  1  is facilitated by a tearing action at the perforation, thereby removing a sealed fin  6  from the main body  7  of the packaging container  1 . Optionally, if not fully teared the sealed fin  6  is not removed from the main body  7  but it may remain partially attached to the opened packaging container  1 . 
     As described earlier, the packaging container  1  may be manufactured for enclosing a frozen food product, such as an ice lolly. Should the content of the packaging container  1  freeze in the volume  8  between the perforation  5  and the seal  3 , it will be very difficult to open the packaging container  1 . 
     An improved packaging container  10  is thereby provided, as illustrated in  FIG. 2 . As for the prior art packaging container  1  shown in  FIG. 1 , the improved packaging container  10  is produced by forming a tube of a packaging material, and filling the tube with its desired content. The tube has a longitudinal seal  12 , and the filled tube is further sealed by providing repeated transverse thermal seals  13 ,  14  alternatingly 90° transversely in relation to one another. 
     A perforation  15  is provided on each packaging container  10 , for facilitating opening of the closed packaging container  10  in order to access its content, which may be frozen. The perforation  15  is positioned inside the seal  13 , whereby tearing of the perforation  15  will remove a sealed fin  16  from the main body  17  of the packaging container  10 . Optionally, if not fully teared the sealed fin  6  is not removed from the main body  7  but it may be remain partially attached the opened packaging container  1 . 
     As can be seen in  FIG. 2 , the packaging container  10  is further provided with a transversal imprint  19 . The transversal imprint  19  is preferably extending across the entire width of the packaging container  10 , and in parallel with the transversal seal  13 . The imprint  19  is arranged such that the perforation  15  is provided in between the imprint  19  and the transversal seal  13 . The imprint  19  is preferably formed by compressing or folding the packaging material of the packaging container  10 , such that it forms a barrier for the content of the packaging container  10 . Hence, the imprint  19  will prevent, or at least reduce, content to appear in the area of the perforation  15 , and especially to the volume  18  between the imprint  19  and the seal  13 . 
     The transverse seal  13  will form the fin  16  facing out from the packaging container  10 . At the same time, the packaging container  10  tapers uniformly towards the transverse seals  13 ,  14  with the result that a frozen food product inside the packaging container  10  will display an apex which can be pushed through the open end (located at the area of the perforation  15 ) when the fin  16  is removed and the packaging container  10  is opened. 
     The transversal seal  13  preferably reaches approximately 6 mm into the packaging container  10  in the longitudinal direction. The total width of the fin  16  in the longitudinal direction, including the width of the transversal seal  13 , the perforation  15  and the imprint  19  is preferably about 10-30 mm, such as between 15 and 25 mm. 
     Now turning to  FIG. 3 , a sealing device  100  is shown schematically. The sealing device  100  is configured to form part of a filling machine for forming and filling a series of packaging containers  10 . As such a filling machine is well-known in the art, it will not be described further herein. However, in order to provide the improved packaging container  10 , the improved sealing device  100  is needed, which is suggested to replace the existing sealing devices in the filling machine. It should be noted that two identical sealing devices  100  may be provided and arranged in series in the longitudinal direction of the tube, and rotated by 90° relative each other. 
     The sealing device  100  is configured to act on the tube  30  of packaging material  20 , by compressing the tube  30  such that two opposite layers  22   a - b  of the packaging material  20  are brought into contact with each other. 
     A first sealing element  104  is arranged to provide a bottom transversal seal  14  on a downstream packaging container  10   a , by moving towards a first anvil  102  and applying thermal energy to the layers  22   a - b  of packaging material  20 . Plastic material of the packaging material  20  will thereby melt, and allowing the layers  22   a - b  to adhere to each other thereby forming the transversal seal  14 . 
     A second sealing element  108  is arranged to provide a top transversal seal  13  on an upstream packaging container  10   b , by moving towards a second anvil  106  and applying thermal energy to the layers  22   a - b  of packaging material  20 . Plastic material of the packaging material  20  will thereby melt, and allowing the layers  22   a - b  to adhere to each other thereby forming the transversal seal  13 . 
     The first and second sealing elements  104 ,  108  may e.g. be induction heating elements, or of any other type being suitable to seal a packaging material  20 . They are preferably activated simultaneously, and separated in the longitudinal direction to allow a cutter  110  to fully penetrate the packaging material  20 . The cutter  110  may e.g. be a knife, actuated at the same time or shortly after, as the transversal seals  13 ,  14  are provided, such that the downstream packaging container  10   a  is separated from the upstream packaging container  10   b  and the tube  30 . 
     A ruler  120  is provided upstream the second sealing element  108 . The ruler  120  is moveable towards the tube  30 , in order to compress the packaging material  20  (i.e. both layers  22   a - b  of the packaging material  20 ) and thereby form the transversal imprint  19 . The ruler  120  may be blunt, as illustrated in  FIG. 3 , or more sharp depending on the desired properties of the resulting imprint  19 . 
     A flattening section  130  is arranged longitudinally between the ruler  120  and the second sealing element  108 . The flattening section  130  is a flat surface which is configured to push the layers  22   a - b  of the packaging material  20  towards each other such that a relatively flat section of packaging material is obtained, containing a minimum of product content. 
     The packaging material  20  is fed into the sealing device  100  such that the perforation  15 , which is pre-applied to the packaging material  20 , is positioned at the flattening section  130 . 
     Since the perforation  15  shall be located at a position within the flat section  18 , there is a need to control the position of the perforation  15 . This is made by adjusting the protrusion of the ruler  120  giving an adjustment of the length of the packaging container  10 . This flat section  18  is then pushed together, thereby squeezing away most of the product, by means of the shape of the sealing device  100 . The flattening section  130  ends at the ruler  120  such that the imprint  19  will act like a stiffener of the packaging material  20 , thereby reducing the risk that the content of the packaging container  10  enters into the flat section  18  of the packaging container  10 . Due to the width of the flat section  18 , it is possible to locate the perforation  15  within that section  18  and at safe distance to highly stressed and exposed positions, thereby reducing the risk for integrity issues related to the perforation. 
     Also, the resulting shape of the packaging container will provide for a differentiation in appearance and improved décor. 
     A web of packaging material  20  is shown in  FIG. 4 . The packaging material  20  is preferably comprising one or more layers of fibrous material, such as carton or paper, which is covered on both sides with a thermoplastic material, e.g. polyethylene. The side of the packaging material  20  that may be in contact with the food product in the packaging container may also comprise a layer of barrier material, e. g. an aluminium foil which is coated with a thermoplastic material. 
     The web of packaging material  20  forms a series of sections  24 , each section  24  being configured to form an individual packaging container  10 . 
     Each section  24  has a top sealing area  25 , a bottom sealing area  26 , and a longitudinal sealing area  27 . The longitudinal sealing area  27  is configured to form the longitudinal seal  12  of the packaging container  10 , while the top sealing area  25  and the bottom sealing area  26  are configured to form the top transversal seal  13  and the bottom transversal seal  14 , respectively. 
     Each section  24  is also provided with folding lines  28 , indicating the position of the corners of the tetrahedral package shape, and assisting in defining the outside décor of the packaging container  10 , and a perforation  15 . As can be seen in  FIG. 4 , the perforation  15  is arranged at a distance from the folding lines  28 , thereby forming a certain area of the packaging material  20  to obtain the flat section  18 . From the previous description, it should be realized that the imprint  19  will be formed approximately at the longitudinal position where the folding lines  28  start, indicated by the dashed line  19  in  FIG. 4 . It should however be understood that the imprint  19  is formed by means of the sealing device  100  in the filling machine, such that it is not present at the packaging material  20  shown in  FIG. 4  before it is formed into a packaging container, but after. 
     From the description above follows that, although various embodiments of the invention have been described and shown, the invention is not restricted thereto, but may also be embodied in other ways within the scope of the subject-matter defined in the following claims.