Abstract:
The present invention is related a reclosable flowpack comprising: a film (6) comprising one or more polymeric layer(s),—a top fold, a flap fold and a flap, said flap comprising a peelable fm seal joining an upper- end portion and a lower-end portion of said film,—two peelable cross seals closing both ends of the flowpack,—a pressure-sensitive adhesive, the position of said pressure-sensitive adhesive and said flap allowing, after the flowpack has been opened by peeling the fin seal, the reclosing of the flowpack by unfolding the lower-end portion and folding the upper-end portion of the film onto the pressure-sensitive adhesive for forming a lap seal.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is related to a reclosable flowpack. 
       STATE OF THE ART 
       [0002]    Reclosable flowpacks are well known by those skilled in the art. The reclose means are either of a mechanical kind, such as zips, or based on adhesive tapes. Zips are for example disclosed in documents U.S. Pat. No. 5,561,966 or U.S. Pat. No. 4,894,975. 
         [0003]    Reclosable flowpacks comprising adhesive tapes are for example disclosed in documents U.S. Pat. No. 5,078,509, U.S. Pat. No. 4,622,799 and US 2004/0091183. For example, EP 1 939 106 discloses a reclosable flowpack comprising a fin seal, said fin seal comprising an adhesive used both for closing the package during the shelf life of the product and for reclosing it after a first use. 
         [0004]    Document WO 01/10736 discloses a reclosable packaging with two permanent non-peelable cross-seals. This packaging comprises a top fold but has no flap fold. 
       AIMS OF THE INVENTION 
       [0005]    The present invention is an alternative to those known systems, presenting several advantages, such as the possibility to increase the volume of the pack upon reclosing, providing an easy access to the packaged items and reducing the risk of having the packaged goods in contact with the adhesive tape. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is related to a reclosable flowpack comprising:
       a polymeric film comprising one or more polymeric layer(s),   a top fold, a flap fold and a flap, said flap comprising a peelable fin seal joining an upper-end portion and a lower-end portion of said film,   two peelable cross seals closing both ends of the flowpack,   a pressure-sensitive adhesive,
 
the position of said pressure-sensitive adhesive and said flap allowing, after the flowpack has been opened by peeling the fin seal, the reclosing of the flowpack by unfolding the lower-end portion and folding the upper-end portion of the film onto the pressure-sensitive adhesive for forming a lap seal.
       
 
         [0011]    Preferred embodiments of the present invention disclose at least one or a suitable combination of the following features:
       the pressure-sensitive adhesive is located on the external surface of the flowpack, under the flap,   the pressure-sensitive adhesive is protected by a transfer tape,   the lengths of the lower-end portion and upper-end portion of the flap and the distance between the top fold and the flap fold are selected so that, when reclosed, said lower-end portion remains unfolded,   the pressure-sensitive adhesive is in contact with the flap fold,   the cross seals join the edge of the flap to the external side of the flowpack,   the film comprises an oriented polymer layer and an aluminium layer,   the opening force of the peelable fin seal according to ASTM D1876 is comprised between 5 and 25 N/15 mm, preferably between 10 and 20 N/15 mm,   the reclosable flowpack comprises a hanging hole located in one of the cross seals,   the length of the upper-end portion is larger than the length of the lower-end portion of the flap,   the length of the lower-end portion is comprised between 60 percent and 90 percent of the length of the upper-end portion,   the upper-end portion of the flap hanging out of the lower-end portion of the flap is peelably sealed on the external surface of the flowpack,   the structure of the film is selected from heat seal lacquer/PET/print layer/PE, or OPP/ print layer/PE, or OPP/print layer/OPP, or print layer/OPP/metalized-OPP/seal layer and print layer/OPP/seal layer,   after opening and reclose, the flowpack is enlarged by the length of the upper-end portion of the film,   the top fold is spaced apart from the flap fold.       
 
     
    
     
       FIGURES 
         [0026]      FIG. 1  represents a schematic front view of a closed flowpack according to the invention, showing the position of the cross-sections (AA and BB) of the following figures. 
           [0027]      FIG. 2  represents a schematic cross-section (BB) of a cross seal of a flowpack according to the invention before opening. 
           [0028]      FIG. 3  represents a schematic cross-section (BB) of a cross seal of another flowpack according to the invention before opening. 
           [0029]      FIG. 4   a  represents a schematic cross-section (AA) of the flowpack of  FIG. 3  before opening. 
           [0030]      FIG. 4   b  represents a schematic cross-section (AA) of the flowpack of  FIG. 4   a  after peeling the fin seal. 
           [0031]      FIG. 4   c  represents a schematic cross-section (AA) of the flowpack of  FIG. 4   a  after unfolding the lower-end portion of the folded film. 
           [0032]      FIG. 4   d  represents a schematic cross-section (AA) of the flowpack of  FIG. 4   a  after the removal of the transfer tape, and reclosing. 
           [0033]      FIG. 5  represents a schematic cross-section (AA) of another flowpack according to the invention, wherein the pressure-sensitive adhesive is located on the lower-end portion of the folded film. 
           [0034]      FIG. 6  represents a schematic cross-section (AA) of another flowpack according to the invention, wherein the pressure-sensitive adhesive is located on the upper-end portion of the folded film. 
       
    
    
     KEY 
       [0000]    
       
           1 : flowpack 
           2 : peelable fin seal 
           3 : pressure-sensitive adhesive 
           4 : transfer tape 
           5 : upper end of the folded film (upper-end portion) 
           6 : foldable material (polymer film/sheet/multilayer structure) 
           7 : peelable cross seal 
           8 : lower end of the folded film (lower-end portion) 
           9 : hanging hole 
           10 : flap 
           11 : part of the cross seals located between the flap and the top fold of the flowpack 
           12 : top fold 
           13 : flap fold 
           14 : peelable seal maintaining the flap in position during the shelf life of the flowpack. 
       
     
       DETAILED DESCRIPTION OF THE INVENTION 
       [0049]    The present invention is related to a reclosable flowpack  1  essentially made of a folded polymeric film  6 . 
         [0050]    In the following description, the expressions “polymeric film”, “film” or “sheet” are used in an equivalent manner. 
         [0051]    A flowpack is usually formed in a form fill seal machine. In such a machine, a flat polymeric film from a reel is fed to a first folding unit wherein the film is shaped in the form of a tube. The side ends of the film are hanging out of the formed tube and are sealed together, according to an inside-inside seal, forming a fin seal. The tube is then flattened, forming a top and a bottom fold, the flap being located somewhere in the middle. Due to manufacturing constraints, the flap fold is usually spaced away from both the top and the bottom folds. Cross seals are then performed on the tube to produce a closed package, and cross cuts define the individual package. Due to the position of the flap, a first part of the cross seals is located between the top fold and the flap fold, and a second part of the cross seals is located between the bottom fold and the flap fold, so that when only the fin seal is opened, the access to the packaged goods is difficult. 
         [0052]    The flowpack  1  of the invention is closed by two peelable cross seals  7  and a flap  10  comprising a peelable fin seal  2  joining an upper-end portion  5  of the folded film  6  and a lower-end portion  8  of the folded film. The flowpack  1  further comprises a pressure-sensitive adhesive (PSA)  3  protected by a transfer tape  4 . The pressure-sensitive adhesive  3  is located under a flap  10 . In this location, the transfer tape  4  is protected by the flap  10 , which can advantageously be peelably sealed in the cross seal area onto the flowpack body, as represented in  FIG. 2  (peelable seal  14 ). In that case, the seal is advantageously performed by sealing the inner layer (sealant layer) of the upper-end portion  5  of the flap hanging out of the lower-end portion  8  of the flap on the external surface of the flowpack  1 . 
         [0053]    By “transfer tape  4 ” or “release tape  4 ” in the present invention is meant a layer protecting the pressure-sensitive adhesive  3  (PSA, also called permanent tacky adhesive), said layer being easily peeled off from the pressure-sensitive adhesive  3 , i.e. the adhesion between the transfer tape and the PSA being lower than the adhesion between the folded polymeric sheet and the PSA. 
         [0054]    By “peelable” is meant that the seal can be broken by delamination at the original interface (adhesive failure), or by propagating a fracture through a specially-designed peelable layer (cohesive failure), or by delaminating one of the film at an interface between two layers (adhesive failure between two layers). 
         [0055]    As represented in  FIGS. 4   a  to  4   b , the flowpack  1  is first opened by breaking the peelable fin seal  2  and the parts  11  of the cross seals  7  located between the flap  10  and the top fold  12  of the flowpack  1 . This peeling is obtained by tearing the upper-end portion  5  of the folded film  6  from the lower-end portion  8 . 
         [0056]    In order to reclose the flowpack  1 , the lower-end portion  8  of the folded film is then unfolded, as represented in  FIG. 4   c , thereby uncovering the transfer tape  4 . An advantage of the presence of the unfolded lower-end portion  8  is that, in reclosed position, it improves the tightness of the reclosed flowpack and reduces the risk of having the package goods in direct contact with the pressure-sensitive adhesive  3 . In order to reduce the risk of having the package goods in direct contact with the pressure-sensitive adhesive  3 , the length “z” of the lower-end portion  8  of the film is at least 5 mm, preferably at least 8 mm, more preferably at least 10 mm. 
         [0057]    The transfer tape  4  is then removed and the flowpack is reclosed by folding the upper-end portion  5  of the folded film  6  onto the pressure-sensitive adhesive  3 , forming a lap seal as represented in  FIG. 4   d.    
         [0058]    The pressure-sensitive adhesive  3  can be located at several positions, as represented in  FIGS. 2 ,  3 ,  5  and  6 . In the embodiment of  FIGS. 2 and 3 , the pressure-sensitive adhesive  3  is located on the external side of the folded film, with the transfer tape  4  on the side oriented towards the lower-end portion  8  of the folded film. 
         [0059]    In that case, the total perimeter of the flowpack can be enlarged by the length of the upper-end portion  8  of the film exceeding the area covered by the adhesive  3 . This induces an enlargement of the size of the flowpack by about half the length “x” of the upper-end portion  5  of the flap  10 . 
         [0060]    In order to be able to reclose the package without folding the lower-end portion  8  of the film forming the flowpack, in the example of  FIG. 2 , the length “z” of said lower-end portion  8  is smaller than the distance “y” between the flap fold  13  and the top fold  12  of the flowpack  1 , increased by half the length “x” of the upper-end portion  5  of the flap  1 , minus half the width of the adhesive  3 . 
         [0061]    Alternatively, as represented in  FIG. 5 , the pressure-sensitive adhesive  3  can be located on the lower-end portion  8  of the folded film  6 . In that case, the flowpack  1  can gain more space when reclosed. In both embodiments of  FIGS. 2 and 4 , the pressure-sensitive adhesive  3  and the transfer tape  4  are well protected by the flap during the shelf life of the flowpack  1 . 
         [0062]    In order to further increase the size of the reclosed package, the pressure-sensitive adhesive can be located on the upper-end portion  5  of the folded film  6 , as represented in  FIG. 6 . This position ensures the possibility of having the largest possible reclosed flowpack  1 , but the transfer tape  4  and the pressure-sensitive adhesive are less protected during the shelf life of the flowpack  1 . 
         [0063]    Typical structures for flowpack films/sheets suitable for the invention are:
       heat seal lacquer/PET/print layer/PE,   OPP/print layer/PE,   OPP/print layer/OPP,   print layer/OPP/metalized-OPP/seal layer,   print layer/OPP/seal layer.       
 
         [0069]    Pressure-sensitive adhesives (permanent tacky adhesives) usually have compositions based on natural and/or synthetic rubber, optionally used in combination with modified cellophanes, phenolformaldehyde resins or waxes. In addition to rubbers, polymers based on styrene, (meth)acrylic acid or vinyl ether are widely used, alone or as a mixture. Lastly, silicone resins may also be employed. Compositions including mixtures of natural and synthetic rubbers and copolymers of (meth)acrylic acid and styrene are preferred. 
         [0070]    These pressure-sensitive adhesives are deposited onto the substrate (web) at a thickness of approximately 1 to 5 g/m 2 . Pressure-sensitive adhesive can be applied in the form of a solution or of a dispersion, or even in the molten state. Coating-deposition techniques well known by those skilled in the art may be employed, such as, for example, heliographic or flexographic printing, or offset printing. In this embodiment, the flap  10  directly adheres to the pressure-sensitive adhesive  3 . In an alternative embodiment, the pressure-sensitive adhesive  3  is deposited on a transfer tape  4  slitted in the right dimensions, and then applied to the film  6  before or during the manufacturing of the flowpack  1 . 
         [0071]    Example of suitable commercially available pressure-sensitive adhesives are produced by Henkel under the grade names 22-263, 22-272, 22-392, 22-477, 22-848, 22-861 or produced by Sun Chemical under the grade names S7188, S7883, S7936, S7979, S7985, S8011, S8039, S8041, S8044, S8046, S8057, S8078, S8083, S8093, S8095, S8110, S9044, C1225, S8124, S8129, S8130.