Patent Publication Number: US-2021163176-A1

Title: Opening device for a package adapted to contain a pourable product and package comprising an opening device

Description:
TECHNICAL FIELD 
     The present invention relates to an opening device for a package adapted to contain a pourable product, in particular a pourable food product. 
     BACKGROUND ART 
     As it is generally known, many pourable food products, such as fruit juice, UHT (ultra-high temperature-treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material. 
     A typical example is the parallelepiped-shaped package for pourable food products known as Tetra Brik Aseptic (registered trademark), which is made by folding and sealing a laminated sheet of packaging material. 
     In particular, the packaging material has a multilayer structure substantially comprising a base layer for stiffness and strength, which may be made of fibrous material, e.g. paper or mineral-filled polypropylene material, and a number of lamination layers made of heat-seal plastic material, e.g. polyethylene films, covering both sides of the base layer. 
     In the case of aseptic packages for long-storage products, such as UHT milk or fruit juice, the packaging material also comprises a layer of gas-barrier material, e.g. aluminum foil or ethyl vinyl alcohol (EVOH) film, which is superimposed on a layer of heat-seal plastic material, and is in turn covered with another layer of heat-seal plastic material. This latter layer of plastic material forms the inner face of the package eventually contacting the pourable food product. 
     Packages of this sort are normally produced on fully automatic packaging machines, in which a continuous tube is formed from the sheet of packaging material. 
     Furthermore, the sheet of packaging material is sterilized in the packaging machine by applying a chemical sterilization agent, which is then removed after sterilization is completed. 
     Subsequently, the sheet of packaging material is maintained in a closed, sterile environment and is folded and sealed longitudinally to form the tube. 
     In order to complete the forming operations, the tube is filled from above, by means of a pipe, with the pourable food product and is formed, sealed and subsequently cut along equally spaced transversal cross sections. 
     Pillow packs are obtained thereby, which have a longitudinal sealing band, a top transversal sealing band and a bottom transversal sealing band, and which are then folded mechanically to form respective finished substantially parallelepiped-shaped packages. 
     To open the packages described above, opening devices made of plastic material have been proposed. 
     In particular, according to a widespread technology, opening devices are known to be molded, by injection molding, directly on a so-called prelaminated hole, i.e. a hole formed through the base layer only and covered, by means of a lamination process, by the other lamination layers of the packaging material, including the layer of gas-barrier material. 
     In other words, the molten plastic material is injected onto, and through, a sheet cover portion of the prelaminated hole made of such lamination layers. 
     According to an alternative solution, such sheet cover portion may be defined by a patch attached to the packaging material to close a hole formed, in this case, through the full thickness of the packaging material. 
     An example of opening device produced by injection molding is known from EP-B-2955122. In this solution, the molten plastic material is injected onto a first side of the sheet cover portion (i.e. the side of the sheet cover portion eventually facing towards the inner environment of the package) in order to cover such prelaminated hole up to an annular peripheral portion thereof. 
     In this way, a plastic material confetti portion directly attached to the first side of the sheet cover portion is obtained. 
     Furthermore, the plastic material confetti portion attached to the first side of the sheet cover portion defines, together with the sheet cover portion itself, a user-tearable portion of the package. 
     During molding, the plastic material is forced to pierce the sheet cover portion, due to the injection pressure and the geometry of the molding device used to form the opening device, so as to pass through the sheet cover portion, and protrude from a second side of the sheet cover portion, opposite to the first side. 
     More precisely, the lamination layers forming the sheet cover portion and closing the hole of the base layer are first pierced through and then resealed by the plastic material forming the opening device. 
     In detail, the plastic material is forced to pierce the sheet cover portion in order to form:
         a pull-member, in the example shown in EP-B-2955122, a pull-ring, protruding from the second side of the sheet cover portion and adapted to be pulled by the user, so as to cause a tearing of the user-tearable portion and causing the package to open; and   a pouring spout, also protruding from the second side of the sheet cover portion and configured to guide the pourable product exiting from the package, when this latter is emptied under the action of the user.       

     In the configuration described in EP-B-2955122, the pouring spout is shaped as a threaded cylindrical neck surrounding the sheet cover portion and is adapted to receive a known screw cap, which allows reclosing of the package. 
     In order to ease the opening of the package, a weakening slot is formed in the plastic material, covered by the sheet cover portion, i.e. by the lamination layers, and delimiting, together with the first side of the sheet cover portion, a weakening region of the user-tearable portion. 
     In this way, the user can easily pull off, by means of the pull member, the user-tearable portion of the package. 
     However, though providing a functionally valid method for separating the user-tearable portion from the packaging material and open the package, the known opening devices are still open to further improvement, in particular as to further ease the opening of the package and as to achieve a neat, clean cut tearing and separation of the user-tearable portion. 
     DISCLOSURE OF INVENTION 
     It is therefore an object of the present invention to provide an opening device, which is designed to fulfill at least one of the above-mentioned needs in a straightforward and low-cost manner. 
     This object is achieved by an opening device as claimed in claim  1 . 
     It is a further object of the present invention to provide a package, which is designed to fulfill at least one of the above-mentioned needs in a straightforward and low-cost manner. 
     This object is achieved by a package as claimed in claim  15 . 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: 
         FIG. 1  is a sectional view, with parts removed for clarity, of a package for containing pourable products, made of a sheet of packaging material on which an opening device according to the present invention is molded; 
         FIG. 2  is a schematic section view of the sheet of packaging material of  FIG. 1  before the opening device is molded thereon; 
         FIG. 3  is a perspective view of the opening device of  FIG. 1 ; 
         FIG. 4  is a bottom view of the opening device of  FIG. 1 ; and 
         FIG. 5  is a section along line V-V of  FIG. 4 , with parts removed for clarity. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     With reference to  FIG. 1 , number  1  indicates as a whole a package made of a multilayer sheet of packaging material  2 , adapted to contain a pourable product, and to which an opening device  3  of plastic material is applied. 
     In particular, package  1  is adapted to contain a pourable food product, such as milk, water, fruit juice or the like. 
     In the example shown, opening device  3  is applied to package  1  by molding, preferably by injection molding, plastic material on a specific area of package material  2 . 
     With particular reference to  FIG. 2 , packaging material  2  comprises a base layer  4  for providing stiffness and strength, which may be made of fibrous material, e.g. paper or mineral-filled polypropylene material, and a cover layer arrangement  5 . 
     In detail, cover layer arrangement  5  comprises a first covering layer  5   a  and a second covering layer  5   b,  both made of heat-seal plastic material, e.g. polyethylene film, and covering both sides of base layer  4 . 
     In the case of an aseptic package  1  for long-storage food products, cover layer arrangement  5  also comprises a barrier layer  6  made of gas-barrier material, e.g. aluminum foil or ethyl vinyl alcohol (EVOH) film, which is superimposed on the second covering layer  5   b  and is in turn covered with a third covering layer  5   c  of cover layer arrangement  5 , made of the same heat-seal plastic material of first covering layer  5   a  and second covering layer  5   b.    
     In particular, third covering layer  5   c  forms the inner face of package  1  eventually containing the pourable food product. 
     In other words, first covering layer  5   a,  second covering layer  5   b,  barrier layer  6  and third covering layer  5   c  define lamination layers applied, by a lamination process, to base layer  4  when producing packaging material  2  in the form of a continuous sheet. 
     Packaging material  2  further comprises a number of removable portions  8  (only one shown in  FIG. 2 ) equally spaced on a lengthwise direction of packaging material  2  and to which respective opening devices  3  are subsequently molded. 
     In the present description, reference is made to a single opening device  3  molded, by means of a molding device (not shown), on a respective removable portion  8  of packaging material  2 , for the sake of simplicity. 
     According to this non-limiting preferred embodiment shown, removable portion  8  is defined by a so-called prelaminated hole  9 , i.e. a through hole formed only through base layer  4  of packaging material  2  and covered by cover layer arrangement  5 , i.e. by first covering layer  5   a,  second covering layer  5   b,  barrier layer  6  and third covering layer  5   c.    
     In particular, prelaminated hole  9  comprises a sheet cover portion  10  of opening device  3 , which is made of the above-mentioned lamination layers and closes the through hole formed in base layer  4 . 
     Preferably, sheet cover portion  10  is an integral part of cover layer arrangement  5 . 
     In an alternative embodiment not shown, sheet cover portion  10  may be made of only one or more of first covering layer  5   a,  second covering layer  5   b,  barrier layer  6  and third covering layer  5   c.  For example, sheet cover portion  10  may be made solely of barrier layer  6 . 
     In another alternative embodiment not shown, sheet cover portion  10  may be defined by a patch attached to packaging material  2  to cover a hole formed, in this case, through the full thickness of packaging material  2 . 
     As visible in  FIGS. 3 and 4 , sheet cover portion  10  has an axis A identifying two parts of sheet cover portion  10 . 
     In the non-limiting example shown, sheet cover portion  10  has a substantially elongated shape and mainly extends along axis A. In this last case, axis A is a longitudinal axis for sheet cover portion  10 . 
     In detail, sheet cover portion  10  has a substantially rectangular shape with differently lengthened short sides and with the long sides parallel to axis A. 
     As shown in  FIGS. 1, 4 and 5 , opening device  3  further comprises a wall portion  11  having a first surface  11   a  applied, in particular molded, to a first side  10   a  of sheet cover portion  10 , i.e., in this preferred embodiment shown, the side eventually facing towards the inner environment of package  1  once package  1  is formed. 
     In particular, wall portion  11  defines, together with sheet cover portion  10 , a user-tearable portion  15  of package  1 , configured to be torn by the user, in order to open package  1 . 
     Opening device  3  further comprises a pull-member, in particular a pull tab  20  projecting integrally from first surface  11   a  of wall portion  11 , passing through sheet cover portion  10 , and protruding from a second side  10   b  of sheet cover portion  10 , opposite to first side  10   a.    
     More specifically, pull tab  20  and wall portion  11  are integrally formed in one single piece by molding the plastic material on first side  10   a  of sheet cover portion  10 , by means of the above-mentioned molding device. 
     In particular, during molding, the plastic material is forced to pierce sheet cover portion  10 , due to the pressure applied by means of the molding device and due to the geometry of the molding device (in a manner known and not described in detail), thereby creating a first pierced area  13 , through which pull tab  20  protrudes. In use, pull tab  20  is adapted to be pulled by the user in a direction substantially parallel to axis A, so as to cause tearing of user-tearable portion  15  along the same direction. 
     In the example shown, pull tab  20  comprises:
         a curved portion  22 , projecting transversally from first surface  11   a  of wall portion  11 ; and   a straight portion  23 , extending from curved portion  22  along a direction substantially parallel to axis A and above sheet cover portion  10 , and has a substantially elongated, in particular oval, shape.       

     In detail, straight portion  23  presents a number of grooves  21  configured to ensure an optimal grip for the user, so as to ease pulling of pull tab  20 . 
     As shown in  FIGS. 1, 3, 4 and 5  opening device  3  also comprises a pouring spout  12  projecting integrally from first surface  11   a  of wall portion  11 , passing through sheet cover portion  10 , and protruding from second side  10   b  of sheet cover portion  10 . 
     In detail, wall portion  11  and pouring spout  12  are molded in one piece and pouring spout  12  is configured to guide the pourable product exiting from package  1 , once user-tearable portion  15  is torn by the user. 
     More specifically, during molding, the plastic material is forced, due to the pressure applied by means of the molding device and due to the geometry of the molding device (in a manner known and not described in detail), to pierce sheet cover portion  10 , thereby creating a second pierced area  14  of sheet cover portion  10 , through which pouring spout  12  protrudes. 
     In the example shown, pouring spout  12  is defined by a curved wall  16  projecting transversally from first surface  11   a  of wall portion  11  in a direction opposite to the direction along which straight portion  23  of pull tab  20  extends. 
     As visible in  FIGS. 1, 4 and 5 , wall portion  11  comprises a linear weakening slot  17  formed into part of the thickness of wall portion  11  and open at a second surface  11   b  of wall portion  11  opposite to first surface  11   a.    
     In detail, as visible in particular in  FIG. 4 , linear weakening slot  17  is substantially U-shaped and extends within wall portion  11  symmetrically with respect to axis A. 
     In greater detail, linear weakening slot  17  comprises a first longitudinal portion  17   a  and a second longitudinal portion  17   b,  extending on opposite respective sides of wall portion  11 , with respect to axis A, and a third transversal portion  17   c  connecting, at opposite ends thereof, first longitudinal portion  17   a  and second longitudinal portion  17   b.    
     More specifically, first longitudinal portion  17   a  and second longitudinal portion  17   b  extend along a direction substantially parallel to axis A; third transversal portion  17   c  extends along a direction substantially transversal to axis A. 
     In particular, linear weakening slot  17  delimits, together with first surface  11   a  of wall portion  11 , a linear weakening region  18 ,  18   a  of user-tearable portion  15 . 
     More in particular, first longitudinal portion  17   a  and second longitudinal portion  17   b  delimit, together with first surface  11   a,  a linear weakening portion  18  of linear weakening region  18 ,  18   a  ( FIG. 5 ); third transversal portion  17   c  delimits, together with first surface  11   a,  a further linear weakening portion  18   a  of linear weakening region  18 ,  18   a  ( FIG. 1 ). 
     Since linear weakening slot  17  is substantially U-shaped, also linear weakening region  18 ,  18   a,  being delimited by linear weakening slot  17  and first surface  11   a,  is substantially U-shaped and extends within wall portion  11  substantially along and above linear weakening slot  17 . 
     In detail, linear weakening region  18 ,  18   a  has a thickness smaller than the total thickness of wall portion  11 . In this way, pulling of pull tab  20  will cause, in use, a tearing of user-tearable portion  15  along linear weakening region  18 ,  18   a.    
     In greater detail, further linear weakening portion  18   a  is, in use, the first to tear once pull tab  20  is pulled by the user, along with the part of sheet cover portion  10  directly above further linear weakening portion  18   a.    
     According to an important aspect of the present invention, opening device  3  comprises a pair of linear rib elements, in particular a pair of linear ribs  24 , projecting integrally from first surface  11   a  of wall portion  11  through sheet cover portion  10 , so as to produce respective pierced areas  25 , in particular linear pierced areas  25 , of sheet cover portion  10 . 
     Furthermore, linear ribs  24  protrude from second side  10   b  of sheet cover portion  10 , extend parallel to at least part of linear weakening slot  17 , and are configured to promote, in use, tearing of user-tearable portion  15  along linear weakening region  18 ,  18   a,  in particular along linear weakening portion  18 , as better explained in the following. 
     In detail, linear ribs  24  project integrally from opposite sides of first surface  11   a  of wall portion  11 , with respect to axis A. 
     As visible in  FIG. 5 , one linear rib  24  extends on first surface  11   a  above and parallel to first longitudinal portion  17   a  of linear weakening slot  17  and the other linear rib  24  extends on first surface  11   a  above and parallel to second longitudinal portion  17   b  of linear weakening slot  17 . 
     According to this preferred embodiment shown, each linear rib  24  comprises a first wall  26  projecting from first surface  11   a  of wall portion  11 , protruding transversally from second side  10   b  of sheet cover portion  10 , through the respective pierced area  25 , and extending on wall portion  11 , so as to follow at least part of linear weakening slot  17 . 
     In particular, one first wall  26  extends on first surface  11   a  so as to follow first longitudinal portion  17   a  of linear weakening slot  17 , and the other first wall  26  extends on first surface  11   a  so as to follow second longitudinal portion  17   b.    
     According to another aspect of the present invention, first wall  26  is at least partially uncovered by sheet cover portion  10  and, therefore, by cover layer arrangement  5 . 
     More precisely, during molding, the plastic material, due to pressure and to the geometry of the molding device, pierces sheet cover portion  10 , thereby forming pierced areas  25 . During this process, each first wall  26  projects from first surface  11   a,  pre-tearing and lifting up part of sheet cover portion  10 . In this way, first wall  26  of each linear rib  24  remains uncovered by sheet cover portion  10 , i.e. from cover layer arrangement  5 . 
     As visible in  FIG. 5 , each first wall  26  has a planar straight shape and delimits, together with first surface  11   a  of wall portion  11 , a relative acute angle, thereby defining a respective sharp edge  27 . 
     In detail, each sharp edge  27  extends on first surface  11   a  parallel to at least part of linear weakening slot  17  and is configured to promote, in use, tearing of user-tearable portion  15  along linear weakening portion  18 . 
     In greater detail, one sharp edge  27  extends on first surface  11   a  parallel to first longitudinal portion  17   a  of linear weakening slot  17 , and the other sharp edge  27  extends on first surface  11   a  parallel to second longitudinal portion  17   b.    
     According to this non-limiting preferred embodiment shown, linear weakening slot  17  has a substantially trapezoidal cross-section and comprises:
         a base surface  28 , which is closer to first side  10   a  of sheet cover portion  10  than second surface  11   b  of wall portion  11 ; and   a first lateral side  29  and a second lateral side  30 , projecting transversally from respective opposite end sides of base surface  28  towards second surface  11   b  of wall portion  11 .       

     In detail, second lateral side  30  is closer to the relative sharp edge  27  than first lateral side  29 . 
     In greater detail, first wall  26  and base surface  28  face one another through sheet cover portion  10 , so as to force any possible external gas agent to travel, through wall portion  11 , from first wall  26  to base surface  28  along a non-rectilinear path. 
     In other words, the relative positioning of each linear rib  24  and the respective first longitudinal portion  17   a  or second longitudinal portion  17   b  of linear weakening slot  17  ensures that any possible external gas agent, such as oxygen, has to travel along a labyrinth-shaped path in order to reach linear weakening slot  17  and, thus, the inner environment of package  1 . 
     Base surface  28 , first side  10   a  and sharp edge  27  delimit linear weakening portion  18 . 
     In particular, linear weakening portion  18  is configured to tear along a tearing line  31 , which extends in use, within wall portion  11 , from sharp edge  27  towards base surface  28 , transversally with respect to first surface  11   a  of wall portion  11 . 
     Preferably, tearing line  31  extends from sharp edge  27  towards the end side of base surface  28  from which second lateral side  30  of linear weakening slot  17  projects. 
     In practice, due to the conformation of linear weakening slot  17  and due to the relative positioning of linear weakening slot  17  and linear ribs  24 , tearing line  31  is a preferred and guided tearing line for linear weakening portion  18 . In this way, a clean tearing of user-tearable portion  15  can be achieved. 
     As visible in particular in  FIG. 5 , each linear rib  24  further comprises a respective second wall  32 , projecting transversally from the corresponding first wall  26  and extending towards first surface  11   a  of wall portion  11 . 
     In detail, second wall  32  has a curved shape and is smoothly connected to first surface  11   a  by means of a fillet  33 . 
     In particular, fillet  33  provides a smoother connection for second wall  32  with first surface  11   a  than the connection of first wall  26  with first surface  11   a,  i.e. sharp edge  27 . 
     In greater detail, second wall  26  is covered by sheet cover portion  10 , i.e. by cover layer arrangement  5 . 
     In use, when pull tab  20  is first pulled by the user, further linear weakening portion  18   a  breaks, thanks to the presence of third transversal portion  17   c  of linear weakening slot  17 . Therefore, user-tearable portion  15  begins to separate from package  1 . 
     Then, as the pulling action continues, thanks to the presence of sharp edges  27  and to the relative positioning of these latter and linear weakening slot  17 , user-tearable portion  15  continues to tear along linear weakening portion  18 . More specifically, linear weakening portion  18  tears along tearing line  31 , thereby providing a guided, neat and clean tearing of user-tearable portion  15 . 
     The advantages of opening device  3  according to the present invention will be clear from the foregoing description. 
     In particular, thanks to the configuration of linear ribs  24 , a guided tearing path for tearing of user-tearable portion  15  is provided, i.e. tearing line  31  of linear weakening portion  18 . In fact, according to known properties of fracture mechanics, tearing of user detachable portion  15  will begin from sharp edge  27  and not from fillet  33 . 
     Furthermore, thanks to the fact that first walls  26  are uncovered by cover layer arrangement  5 , sheet cover portion  10  is already pre-torn when opening of package  1  begins. In this way, only the plastic material of user-tearable portion  15  has to be torn and, therefore, a neat and clean tearing of user-tearable portion  15  can be thereby achieved. Also, any possible stretching of cover layer arrangement  5  during opening is avoided. 
     In addition, despite first walls  26  are uncovered by cover layer arrangement  5 , i.e. from barrier layer  6 , and are exposed to external agents, such as oxygen, the particular configuration and relative positioning of linear ribs  24  and linear weakening slot  17  provide a labyrinth-shaped path for such external agents to enter the inner environment of package  1 . 
     Clearly, changes may be made to opening device  3  as described herein without, however, departing from the scope of protection as defined in the accompanying claims. 
     In particular, linear ribs  24  may be totally uncovered by sheet cover portion  10 , i.e. cover layer arrangement  5 .