Patent Publication Number: US-2022234804-A1

Title: Sealed single-dose break-open package, device and method for making

Description:
FIELD OF TECHNOLOGY 
     The present invention relates to a sealed single-dose break-open package comprising a pre-weakened area, a device and a method for making a weakened area. 
     PRIOR ART 
     Patent application WO2008038074A2 describes a sealed single-dose break-open package; the sealed package comprises a sheet of semirigid plastic material and a sheet of flexible plastic material, which is set on top of and welded to the first sheet of semirigid plastic material so as to define a sealed pocket that contains a dose of a fluid product. The sheet of semirigid plastic material centrally has a pre-weakened area, which guides a controlled breakage of the sheet of semirigid plastic material in order to cause the formation of an outlet opening for the product through the sheet of semirigid plastic material itself. In other words, in order to open the sealed package, a user must grab the sealed package itself with the fingers of one hand and fold the sealed package in a “V” shape until the sheet of semirigid plastic material breaks at the pre-weakened area. The pre-weakened area comprises an inner incision, which is obtained through an inner surface (namely, one facing the pocket) of the sheet of semirigid plastic material, and an outer incision, which is obtained through an outer surface of the sheet of semirigid plastic material and is aligned with the inner incision. 
     In patent application WO2008038074A2, the incisions vary in depth to cause a gradual breakage of the sheet of semirigid plastic material when folding the sealed package in a “V” shape. However, making incisions that vary in depth is relatively complicated as it requires the movement of the knives of the incision unit to be very precise; among other things, the movement of the knives of the incision unit tends to decrease in precision as the operating speed increases and, as a consequence, if aiming to obtain a very highly precise movement of the knives of the incision unit, particularly high operating speeds cannot be reached. 
     Furthermore, the sealed single-dose package described in patent application WO2008038074A2 does not allow the product contained in the package itself to be applied (spread) precisely and intuitively over a surface and, therefore, such package is not suited to containing spreadable products (or products spreadable over a surface). 
     To make the package, patent application WO2008038074A2 describes the use of a device comprising a reel for feeding a strip of semirigid material and a reel for feeding a strip of flexible material, an incision unit, and a package forming unit comprising a device for feeding the fluid and a sealing device. The incision unit has two parallel, facing plates, which are movable towards each other to grip the strip of semirigid plastic material and which support the knives. Each plate is pushed towards the other by a respective linear actuator so as to hold the strip of semirigid material and have each part thereof make an incision. 
     Furthermore, sealed single-dose break-open packages are known which have a Ω-shaped incision made in a central area of the sheet of semirigid plastic material. This incision allows the breakage of the package and the discharge of the product to be controlled. Once opened, the Ω shape of the incision allows a fluid product to be directly spread over the surface for application. 
     These packages also have drawbacks. When opened, the product tends to seep out from the lateral segments of the incision and, therefore, its distribution is not adequately controlled. 
     Moreover, known packages are not suited to dosing granular or powder products. When the product is in granules, it tends to spurt out of the package quickly upon opening. When the product is in powdered form, a certain quantity of residual product often remains inside the package. 
     DESCRIPTION OF THE INVENTION 
     The object of the present invention is to provide a sealed single-dose break-open package which allows a controlled distribution of the product. 
     According to one aspect of the present invention, a sealed single-dose break-open package is provided with the features defined in claim  1 . 
     Making a lateral incision at its edge enables a guided opening, which is then completed with the breakage of the sheet at the shaped central incision. Therefore, the product exits the central area rather than the lateral segment, which only serves to direct the folding of the package. 
     To make the pre-weakening, a device is provided with the features defined in claim  13 . 
     The pre-weakening is made according to a method with the features defined in claim  19 . 
     According to another aspect of the present invention, a sealed single-dose break-open package is provided that comprises a first sheet of semirigid plastic material; a second sheet of flexible plastic material set on top of and welded to the first sheet so as to define a sealed pocket that contains a dose of a product; wherein the first sheet of semirigid plastic material comprises a shaped incision positioned in a central portion of the first sheet, wherein the shaped incision has a least two inclined segments positioned symmetrically with respect to the centre of the sheet and joined to each other at one end so as to form two opposing sides of a triangle. This package enables liquid products to be dosed out in drops. 
     In a preferred embodiment, the incision has a plurality of adjacent pairs of inclined segments, wherein the segments in each pair are positioned symmetrically to each other and are joined to each other at one end so as to form two opposing sides of a triangle. This package enables granular and powder products to be dosed out optimally. 
     According to another aspect of the present invention, an incision tool is provided for making an incision in a sheet, in particular a sheet of semirigid plastic material, comprising a plate-shaped body, in particular rectangular, and at least one protrusion attached to one side of the plate, preferably a longer side of the plate, wherein the protrusion has a substantially “V”-shaped recess. 
     Using this incision tool, a “V”-shaped incision can be made to enable liquid products to be distributed in drops. 
     According to an advantageous embodiment, the incision tool comprises a plurality of protrusions, preferably adjacent, each having a substantially “V”-shaped recess. Using this incision tool, a “zig-zag” incision can be made to enable the controlled distribution of granular and powdered products. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described with reference to the accompanying drawings, which show some non-limiting examples of implementations, in which: 
         FIG. 1  shows a perspective view of a sealed single-dose break-open package made in accordance with the present invention; 
         FIG. 2  shows a perspective view of a first sheet of the sealed package in  FIG. 1 , in a first embodiment; 
         FIG. 3  is a perspective view of an outer surface of the first sheet of the sealed package in  FIG. 1 , in a second embodiment; 
         FIG. 4  is a perspective view of an inner surface of the first sheet of the sealed package in  FIG. 1 , in the second embodiment; 
         FIG. 5  is a perspective view of the package in  FIG. 2 , in a folded configuration; 
         FIG. 6  is a perspective view of a surface of the first sheet of the sealed package, in a third embodiment; 
         FIG. 7  is a perspective view of a surface of the first sheet of the sealed package, in a fourth embodiment; 
         FIG. 8  is a perspective view of the package in  FIG. 7 , in a folded configuration; 
         FIG. 9  is a perspective view of a surface of the first sheet of a sealed double-dose package; 
         FIG. 10  is a perspective view of a surface of the first sheet of the sealed package, in a fifth embodiment: 
         FIG. 11  shows a first step of opening the package in  FIG. 10 ; 
         FIG. 12  shows a second step of opening the package in  FIG. 10 ; 
         FIG. 13  shows a schematic cross-section of a semirigid sheet constituting the sealed package; 
         FIG. 14  is a perspective view of the top part of an incision tool for making a “V”-shaped incision; 
         FIG. 15  is a perspective view of the bottom part of an incision tool for making a “V”-shaped incision; 
         FIG. 16  is a perspective view of the top part of an incision tool for making a “zig-zag” incision; 
         FIG. 17  is a perspective view of a device for making a weakening in a sheet, in a preferred embodiment; 
         FIG. 18  is a perspective view of a plate attached to an incision tool for making a straight incision, in a preferred embodiment; 
         FIG. 19  is a perspective view of an incision tool for making a straight incision, in a preferred embodiment; 
         FIG. 20  is a perspective view of a plate attached to an incision tool for making a shaped incision, in a preferred embodiment; 
         FIG. 21  shows a view from above of a first incision station of the device in  FIG. 17 ; 
         FIG. 22  shows a view from above of a second incision station of the device in  FIG. 17 ; 
     
    
    
     PREFERRED IMPLEMENTATIONS OF THE INVENTION 
     In  FIG. 1 , the number  1  indicates a complete sealed single-dose break-open package. The sealed single-dose package  1  comprises a sheet  2  of semirigid plastic material and a sheet  3  of flexible plastic material, which is set on top of and welded to the sheet  2  of semirigid plastic material so as to define (between the two sheets  2  and  3 ) a sealed pocket  4  that contains a dose of a product  5 . 
     In the embodiment shown, the sheet  2  of semirigid plastic material and the sheet  3  of flexible plastic material have a substantially rectangular shape. The sealed single-dose package  1  could have any other shape: round, elliptic, “bottle”-shaped, rhomboid, pentagonal, hexagonal, triangular, square, “bone”-shaped. The sheet  2  of semirigid plastic material and the sheet  3  of flexible plastic material are substantially flat. The sheet  2  of semirigid plastic material is obtained from a strip of semirigid plastic material. The strip of semirigid plastic material preferably has a thickness of between approximately 200 microns and approximately 500 microns, in particular between approximately 200 microns and approximately 450 microns. 
       FIG. 2  shows an embodiment of the present invention. 
     According to the invention, the first sheet  2  of the package  1  comprises at least one substantially straight pre-weakened incision  6  positioned at a first edge  9  of the first sheet  2 , and at least one shaped incision  7  positioned in a central portion  10  of the first sheet  2 , laterally and at a distance from the substantially straight first incision  6 . 
     In particular, the first straight incision  6  starts at the first edge  9  and extends towards the centre of the package  1 . The first straight incision  6  is substantially perpendicular to the first edge  9  of the package  1 . 
     The incisions  6 ,  7  have the function of guiding, by following a fold in the sealed package  1 , a controlled breakage of the first sheet  2  in order to cause the formation of an outlet opening for the product  5  through the first sheet  2  itself. 
     Preferably, the package  1  comprises at least one substantially straight second incision  8  positioned at a second edge  11  of the first sheet  2 , opposite to the first edge  9 , laterally and at a distance from the shaped incision  7 . 
     In particular, the second straight incision  8  starts at the second edge  11  and extends towards the centre of the package  1 . The second straight incision  8  is substantially perpendicular to the second edge  11  of the package  1 . 
     In particular, the two lateral incisions  6 ,  8  consist of two respective straight segments which are identical in size and aligned to each other. The two lateral incisions  6 ,  8  do not connect with the shaped central incision  7 , but are made up of segments spaced apart from it. In other words, a residual portion of the sheet  2  of semirigid plastic material is interposed between the two straight lateral incisions  6 ,  8  and the shaped central incision  7 . 
     The shaped incision  7  is not a through-incision, which is to say it does not pass through the first sheet  2  of semirigid plastic material. In particular, the incision  7  is made by the plastic deformation of the semirigid plastic material constituting the first sheet  2 . 
     Preferably, the straight incision  6  and/or the straight incision  8  is not a through-incision, which is to say it does not pass through the first sheet  2  of semirigid plastic material. In particular, the straight incision  6  and/or the straight incision  8  is made by the plastic deformation of the semirigid plastic material constituting the first sheet  2 . 
     In the embodiment shown, the incisions  6 ,  7 ,  8  are not through-incisions, which is to say they do not pass through the first sheet  2  of semirigid plastic material. 
     In the embodiment shown in  FIG. 2 , the first sheet  2  comprises a central incision  7  shaped as a curved line, a first straight incision  6  at the first edge  9  and a second straight incision  8  at the opposite edge  11 . 
     In a first embodiment, the central incision  7  and the lateral incision  6  are made on the same surface of the sheet  2  of semirigid plastic material, preferably on the inner surface  12  facing the pocket  4 , as shown in  FIG. 2 . 
     In a preferred embodiment, the shaped central incision  7  is obtained on an inner surface  12  (namely, one facing the pocket  4 ) of the sheet  2  of semirigid plastic material, while the straight lateral incision  6  is obtained on an outer surface  13  (namely, one opposite the pocket  4 ) of the sheet  2  of semirigid plastic material. 
     In the embodiment shown in  FIGS. 3 and 4 , the shaped central incision  7  is obtained on the inner surface  12  of the sheet  2  of semirigid plastic material, while the straight incisions  6 ,  8  are obtained on the outer surface  13  of the sheet  2  of semirigid plastic material. 
     In use, in order to open the sealed single-dose package  1 , a user must grab the package  1  itself with the fingers of one hand and fold it in a ‘V’ shape (as shown in  FIG. 5 ) at the lateral incisions  6 ,  8  until breaking the sheet of semirigid plastic material  2  at the central incision  7 . By breaking the sheet  2  of semirigid plastic material at the central incision  7 , the portion delimited by the curve detaches from the semirigid sheet to form a protrusion  14  substantially shaped as an arc of a circle or semi-ellipse at the product outlet area. The product  5  can then be simply and hygienically released from the sealed single-dose package  1 . 
     According to the illustrations in  FIGS. 6-9 , the central incision  7  extends along a single broken or zig-zag line; which is to say, a line consisting of at least two oriented consecutive and non-aligned segments  15 ,  16  (namely, so that the second end of one segment coincides with the first end of the next segment). 
     In the embodiment in  FIG. 6 , the shaped central incision  7  consists of a main segment  15  which is substantially parallel to a smaller side  18  of the rectangular package  1  and two segments  16 ,  17  which are substantially parallel to each other and substantially perpendicular to the main segment  15  and to the larger side  19  of the rectangular package  1 . In such embodiment, when the package  1  is opened, the portion delimited by the segments  15 ,  16 ,  17  detaches from the semirigid sheet  2  to form a substantially rectangular protrusion at the product outlet area. 
     The packages shown in  FIGS. 2-6  are particularly suitable for dense fluid products, such as creams and glues, since, after opening, the protrusion allows the product to be distributed over the surface. 
     In the embodiments shown in  FIGS. 7-9 , the shaped incision  7  comprises at least two inclined segments  15 ′,  16 ′ positioned symmetrically with respect to the centre of the sheet  2  and joined to each other at one end so as to form two opposing sides of a triangle, in particular an isosceles triangle. 
     In the embodiment in  FIG. 7 , the two inclined segments  15 ′,  16 ′ form the two opposing sides of an isosceles triangle. In this embodiment, when the package  1  is opened, the portion delimited by the segments  15 ′,  16 ′ detaches from the semirigid sheet  2  to form a substantially triangular protrusion  20  at the product outlet area ( FIG. 8 ). This configuration is particularly suitable for liquid products that must be distributed in drops, since the triangular protrusion  21  allows the liquid to be dosed out by sliding it along the triangle up to the vertex, from where it detaches to form the drop. 
     In one embodiment, the “V”-shaped incision is made without making the lateral incisions, while still allowing the product to be distributed in drops. Thus, a sealed single-dose break-open package is obtained that comprises a first sheet  2  of semirigid plastic material; a second sheet  3  of flexible plastic material set on top of and welded to the first sheet  2  so as to define a sealed pocket  4  that contains a dose of a product  5 ; wherein the first sheet  2  of semirigid plastic material comprises at least one shaped incision  7 , which is positioned in a central portion  10  of the first sheet  2  and has at least two inclined segments  15 ′,  16 ′ positioned symmetrically with respect to the centre of the sheet  2  and joined to each other at one end so as to form two opposing sides of a triangle. 
       FIG. 9  shows an embodiment of a double-dose package, wherein two pockets are obtained. Such package is suitable for dual-component products that must be mixed after opening. In these packages, two shaped central incisions  7 ,  7 ′ are made at a space apart from each other. The central incision can be of different shapes, for example “V”-shaped, semi-elliptic or rectangular. 
     In the embodiment in  FIG. 10 , the shaped incision  7  comprises a plurality of adjacent pairs  22  of inclined segments  15 ′,  16 ′, wherein the segments  15 ′,  16 ′ in each pair  22  are positioned symmetrically to each other and are joined to each other at one end so as to form two opposing sides of a triangle. In other words, the pairs  22  of inclined segments  15 ′,  16 ′ form a “zigzag” profile, which extends into the central portion  10  of the package. 
     In this embodiment, the package  1  can be opened in two steps. In a first step, the package  1  is folded along the two straight lateral segments  6 ,  8 , in such a way that the central incision  7  opens up to present a series of adjacent triangles from which the product slowly comes out ( FIG. 11 ). In a second step, by acting perpendicularly relative to the straight lateral segments  6 ,  8 , a complete opening is made at the central incision  7  in such a way that the product comes out completely ( FIG. 12 ). This configuration is particularly suitable for granulated or powdered products, because it allows the product to be dosed out in the first step and, if appropriate, allows the package to be emptied completely in the second step. 
     The dimensions of the incised portions vary according to the dimensions of the package and/or the quantity and density of the product it contains. 
     In one embodiment, the “zig-zag” incision is made without obtaining the lateral incisions, while still allowing the product to be distributed in a controlled manner. 
     Advantageously, the shaped incision  7  has a substantially constant depth (net of inevitable construction tolerances) along its length. 
     Advantageously, the first straight incision  6  and/or the second straight incision  8  has a substantially constant depth (net of inevitable construction tolerances) along its length. 
     Preferably, the depth of the shaped incision  7  is greater than the depth of the first straight incision  6  or the second straight incision  8 . 
     Advantageously, the depth of the first straight incision  6  and/or the second straight incision  8  is approximately ⅓ of the thickness of the first sheet  2 . Preferably, the depth of the shaped incision  7  is approximately ⅔ of the thickness of the first sheet  2 . 
     In a further preferred embodiment, the depth of the shaped incision  7  is ≥70% of the thickness of the first sheet  2  of semirigid plastic material. The shaped incision  7  is not a through-incision, which is to say it does not pass through the first sheet  2  of semirigid plastic material. 
     The depth of the first shaped incision  6  and/or the second straight incision  8  is ≤40% of the thickness of the first sheet  2  of semirigid plastic material. In particular, the depth of the first shaped incision  6  and/or the second straight incision  8  is between 20% and 40% of the thickness of the first sheet  2  of semirigid plastic material. 
     The first sheet  2  of semirigid plastic material is obtained from a single strip of material. The strip of material from which the sheet  2  is obtained is preferably formed by a laminate. 
     The laminate comprises at least one supporting layer  22 , one heat-sealable layer  25  and one insulating layer  24  interposed between the supporting layer  22  and the heat-sealable layer  25 . The insulating or barrier layer  24  aims to ensure impermeability to air and/or light. In the sheet  2  constituting the package  1 , the supporting layer  22  is positioned on the outside (namely, on the side opposite the pocket  4  at the outer surface  13 ) and the heat-sealable layer  25  is positioned on the inside (namely, on the same side as the pocket  4  at the inner surface  12 ). 
     As exemplified in the embodiment shown in  FIG. 13 , the sheet  2  of semirigid plastic material is a laminate and comprises a supporting layer  22  positioned on the outside (namely, on the side opposite the pocket  4  at the outer surface  13 ) and a supporting layer  23  positioned on the inside (namely, on the same side as the pocket  4  at the inner surface  12 ). Between the two supporting layers  22  and  23 , an insulating or barrier layer  24  is provided with the aim of ensuring impermeability to air and/or light; in other words, the barrier layer  24  is enclosed between the two supporting layers  22  and  23  and separates the supporting layers  22  and  23  from each other. Preferably, the supporting layer  23  is clad in a heat-sealable layer  25  that is positioned on the inside (namely, on the same side as the pocket  4  and in contact with the sheet  3  of flexible plastic material so as to perform heat-sealing together with the sheet  3  of flexible plastic material itself). 
     According to some embodiments shown in the accompanying figures, the two supporting layers  22  and  23  can have the same thickness; however, according to other implementations, the two supporting layers  22  and  23  can have different thicknesses, which is to say, the thickness of the supporting layer  22  can be different from the thickness of the supporting layer  23 . 
     By way of a non-limiting example, the sheet  2  of semirigid plastic material could be composed of: a white polystyrene (PS) supporting layer  22  with a thickness of between 100 microns and 200 microns (±10%), an EVOH or dialuminium barrier layer  24  with a thickness of 10 microns (±10%), a white polystyrene (PS) supporting layer  23  with a thickness of between 100 microns and 200 microns (±10%), and a polyethylene (PE) heat-sealable layer  25  with a thickness of 50 microns (±10%). Alternatively, the supporting layers  22  and  23  could be made of preferably biaxially-oriented polylactic acid (PLA) and/or the heat-sealable layer  25  could be made of polypropylene (PP). Polylactic acid (PLA) is generally heat-sealable and, therefore, when the supporting layers  22  and  23  are made of polylactic acid (PLA), the heat-sealable layer  25  could be absent, since the sheet  3  of flexible plastic material could be directly heat-sealable to the polylactic acid (PLA) supporting layer  23 . Moreover, when polylactic acid (PLA) or polypropylene (PP) is used to make the supporting layers  22  and  23 , the thickness of the supporting layers  22  and  23  can be reduced, since polylactic acid (PLA) and polypropylene (PP) enable sufficiently rigid supporting layers  22  and  23  to be obtained even where these are of modest thickness. By way of example, when the supporting layers  22  and  23  are made of polystyrene (PS), the overall thickness of the supporting layers  22  and  23  must be greater than 350-380 microns, whereas when the supporting layers  22  and  23  are made of polylactic acid (PLA) or polypropylene (PP), the overall thickness of the supporting layers  22  and  23  can be as low as 200 microns. 
     According to a different embodiment (not shown), the sheet  2  of semirigid plastic material does not have the supporting layer  23  (namely, the barrier layer  24  is in direct contact with the heat-sealable layer  25 ). The supporting layer  22  has a double thickness (namely, the supporting layer  23  is “incorporated” into the supporting layer  22 ). 
     The straight incisions  6 ,  8  obtained on the outer surface  13  of the sheet  2  of semirigid plastic material are advantageously made by locally deforming the sheet  2  of semirigid plastic material and, in particular, the supporting layer  22  of the sheet  2  of semirigid plastic material. Preferably, the straight incisions  6 ,  8  stop before the barrier layer  24  and therefore do not affect the barrier layer  24  itself. 
     The shaped incision  7  obtained on the inner surface  12  of the sheet  2  of semirigid plastic material is advantageously made by locally deforming the sheet  2  of semirigid plastic material and, in particular, the supporting layer  23  of the sheet  2  of semirigid plastic material. Preferably, the shaped incision  7  stops before the barrier layer  24  and therefore does not affect the barrier layer  24  itself. 
     At the shaped central incision  7 , the heat-sealable layer  25  can be deformed or torn (partially or completely); in any case, at the shaped incision  7  obtained on the internal surface  12  there is no weld of any kind between the sheet  2  of semirigid plastic material and the sheet  3  of flexible plastic material and, therefore, any local damage to the heat-sealable layer  25  has no consequences of any kind. 
     In some embodiments, the barrier layer  24  can be placed between the two supporting layers  22  and  23  to form a barrier for the product contained in the sealed pocket  4 . In some embodiments, the incisions  6 ,  7 ,  8  cannot affect the barrier layer  24 . In some embodiments, the barrier layer  24  could have a sufficient thickness or robustness to allow the incisions to partly penetrate them, provided that the barrier layer  24  is capable of maintaining its function as a barrier. The integrity of the barrier layer  24  of the sheet  2  of semirigid plastic material in some embodiments ensures a barrier and therefore a seal for the contents of the sealed pocket  4  also at the incisions  6 ,  7 ,  8  and, therefore, the sealed pocket  4  is also suitable for containing perishable and/or controlled bacterial products such as foodstuffs, medicines or cosmetics. When the sealed single-dose package  1  is opened by making a “V”-shaped fold in the sealed single-dose package  1  itself, all of the supporting layers  22  and  23 , the barrier layer  24  and the heat-sealable layer  25  of the sheet  2  of material semirigid plastic must be broken at the central incision. 
     In a further embodiment, the shaped incision  7  is made on the same side as the pocket  4  at the internal surface  12  of the sheet  2  of semirigid plastic material in such a way as to cut the barrier layer  24 . The shaped incision  7  then penetrates the heat-sealable layer  25 , the inner supporting layer  23  if present, the barrier layer  24  and reaches the outer supporting layer  22 . 
     In an advantageous embodiment, the sheet  2  of semirigid plastic material is composed of a supporting layer  22 , a barrier layer  24  and a heat-sealable layer  25 . The shaped incision  7  penetrates the heat-sealable layer  25 , the barrier layer  24  and reaches the outer supporting layer  22 . 
     The supporting layer  22  is advantageously made of polystyrene (PS) or polylactic acid (PLA) or polypropylene (PP). The supporting layer  22  preferably has a thickness of between approximately 100 microns and approximately 500 microns (±10%), in particular between approximately 150 microns and approximately 400 microns. The supporting layer  22  still constitutes a barrier even when the barrier layer  24  is cut at the shaped incision  7  when making the incision itself. 
     Preferably, the depth of the shaped incision  7  is ≥70% of the thickness of the first sheet  2  of semirigid plastic material. The shaped incision  7  is not a through-incision, which is to say it does not pass through the first sheet  2  of semirigid plastic material. 
     The first straight incision  6  and/or the second straight incision  8  is made in the same side as the pocket  4  at the outer surface  13  of the sheet  2  of semirigid plastic material. 
     The depth of the first straight incision  6  and/or the second straight incision  8  is ≤40% of the thickness of the first sheet  2  of semirigid plastic material. In a preferred embodiment, the depth of the first straight incision  6  and/or the second straight incision  8  is between 20% and 40% of the thickness of the first sheet  2  of semirigid plastic material. 
     Advantageously, the depth of the first straight incision  6  and/or the second straight incision  8  is less than the thickness of the supporting layer  22 . 
     Advantageously, the incisions  6 ,  7 ,  8  have a substantially constant depth (net of inevitable construction tolerances) along their length. 
     Advantageously, the incisions  6 ,  7 ,  8  are made by the plastic deformation of the material using respective incision tools that are provided with a rounded, unsharpened end for deforming, without cutting, the supporting layers  22  and  23  of the sheet  2  of semirigid plastic material. 
     According to one aspect of the present invention, an incision tool  26 ,  27  is provided for making an incision in a sheet, in particular a sheet of semirigid plastic material  2 . 
     The incision tool  26 ,  27  comprises a plate-shaped body  28 , in particular substantially rectangular, and at least one protrusion  29  attached to one side  30 , preferably a longer side, of the plate  28 , wherein the protrusion  29  has a substantially “V”-shaped recess  31 . 
       FIGS. 14-15  show an embodiment of an incision tool  26  used for making the “V”-shaped incision. 
     The protrusion  29  of the incision tool  26  has a substantially triangular bottom wall  32 . On each side of the triangle, a triangular lateral wall  33 ,  34  extends towards the top of the protrusion  29 , inclined outwards so as to create a substantially “V”-shaped recess. From the edge of each lateral wall  33 ,  34  a substantially triangular portion  35 ,  36  extends in parallel to the bottom wall  32  of the protrusion  29 . 
     An embodiment of an incision tool  27  used for making the “zig-zag” incision is shown in  FIG. 16 . The tool comprises a plurality of protrusions  29 ′ which each have a substantially “V”-shaped recess  31 ′. Each protrusion  29 ′ is made in the same way as with the single protrusion  29  for making the “V”-shaped incision. Preferably, the protrusions  29 ′ are adjacent to each other. 
       FIG. 17  shows a preferred embodiment of a device  40  for making a weakening in a sheet  2  of semirigid plastic material.  FIGS. 18-22  show details of the device  40 . 
     According to the invention, the device  40  comprises at least one first plate  41  connected to at least a first incision tool  51  having at least one straight protrusion  53  for making a substantially straight first incision on a sheet of semirigid plastic material and at least one second plate  42  connected to at least a second incision tool  52  having at least one shaped protrusion for making a shaped incision on a sheet of semirigid plastic material. 
     Advantageously, the first plate  41  is attached to an incision tool  51  with two straight protrusions  53 ,  53 ′ spaced apart from each other so as to simultaneously make two straight incisions spaced apart from each other. In the embodiment in  FIG. 19 , the incision tool  51  has a plurality of straight protrusions  53 ,  53 ′ for making the incision or the incisions in a strip of semirigid plastic material from which more packages are subsequently made. 
     To make double-dose packages, the second plate  42  is attached to an incision tool with two straight protrusions spaced apart from each other. 
     Preferably, the straight protrusion  53 ,  53 ′ of the first incision tool  51  has a constant length so as to make an incision with a constant depth in the sheet of semirigid plastic material  2 . 
     The shaped protrusion of the second incision tool  52  has a constant length so as to make a shaped incision with a constant depth in the sheet of semirigid plastic material  2 . 
     The device  40  is capable of being inserted into an apparatus for manufacturing a sealed single-dose break-open package  1 , wherein a strip of semirigid plastic material preferably with a thickness of between approximately 200 microns and approximately 500 microns, in particular between 200 microns and 450 microns, is collected by a feeding unit (not shown). 
     Advantageously, the device  40  comprises a first incision station  61  for making the straight incision  6 ,  8  and a second incision station  62  for making the shaped incision  7 . 
     The first incision station  61  ( FIG. 21 ) comprises a plate  43  opposite to the first plate  41 , wherein the first plate  41  is movable from a first position far from the opposite plate  43  to a predetermined position near to the opposite plate  43  so as to make a substantially straight incision  6 ,  8  in a strip of semirigid material interposed between the first plate  41  and the opposite plate  43 , thus deforming the strip without cutting it. 
     The second incision station  62  ( FIG. 22 ) comprises a plate  44  opposite to the second plate  42 , wherein the second plate  42  is movable from a first position far from the opposite plate  44  to a predetermined position near to the opposite plate  44  so as to make a shaped incision  7  in a strip of semirigid material interposed between the second plate  42  and the opposite plate  44 , thus deforming the strip without cutting it. 
     Advantageously, the second plate  42  has at least one micrometric measuring tool  45  positioned on the side opposite the opposite plate  43 , which regulates the stroke of the incision tool  52  for making the shaped incision. The micrometric measuring tool  45  can be manual or motorised. Preferably, the stroke of the incision tool  52  is regulated relative to the second plate  42 , and the second plate  42  is movable relative to the opposite plate  43 , which is fixed. 
     In the embodiment shown in  FIG. 17 , the strip of semirigid material passes through the first incision station  61 , where the lateral incisions  6 ,  8  are made on the surface of the strip that will form the outer surface  13  of the sheet of the package, namely, the one opposite the pocket  4  containing the product  5 . The strip passes between the first plate  41  and the opposite plate  43  in a substantially vertical direction from low to high. 
     Using at least one linear actuator or motor, the first supporting plate  41  of the incision tool  51  is moved towards the opposite plate  43  in such a way that one end of the incision tool  51  moves the predetermined distance towards the opposite supporting plate  43  so as to make the deformation in the strip of semirigid material. In this way, the deformation is made with a constant depth. 
     The strip moves upwards in the second incision station  62 , where the shaped central incision  7  is made on the surface opposite the semirigid sheet, namely the one that will form the inner surface  12  of the sheet and that faces the pocket  4  containing the product  5 . 
     During the incision in the first station  61  and/or in the second station  62 , the strip is parked by being rested on the opposite plate  43 ,  44 . 
     Preferably, the second plate  42  has a plurality of incision tools  52  positioned in line, each attached to a respective manual or motorised micrometric measuring tool  45 . 
     The unwinding of the strip is controlled by a motorised unwinder placed above the incision device and comprising two rollers  71 ,  72 , which also have the function of keeping the strip tense so as to keep it in position during the machine standstill step in which the incisions occur. 
     Subsequently, the strip of semirigid plastic material in which the incisions have been made moves to a welding and filling station (not shown), in which the strip of semirigid plastic material is first joined to a strip of flexible plastic material, and filling then takes place as required. 
     According to the invention, one method for making a weakening in a sheet  2  of semirigid plastic material comprises the steps of making at least one substantially straight first incision  6  at a first edge  7  of the sheet  2 ; making at least one shaped incision  7  in a central portion  10  of the sheet  2  laterally and at a distance from the straight first incision  6 , wherein the incisions  6 ,  7  are formed by the plastic deformation of the material of the sheet  2 . 
     Preferably, according to the method at least one substantially straight second incision  8  is made at a second edge  11  of the first sheet  2 , opposite to the first edge  9 , laterally and at a distance from the shaped incision  7 , wherein the second incision  8  is made by the plastic deformation of the material of the sheet  2 . 
     The sealed single-dose package  1  described above has numerous advantages. 
     Firstly, the sealed single-dose package  1  is simpler and cheaper to manufacture than a similar known package  1  (for instance, of the type described in patent application WO2008038074A2), since the incisions  6 ,  7  and  8  have a constant depth and are therefore simpler to make even when operating at high manufacturing speeds. 
     Making a lateral incision at its edge enables a guided opening, which is then completed with the breakage of the sheet at the shaped central incision. Therefore, the product exits the central area rather than the lateral segment, which only serves to direct the folding of the package. 
     Moreover, the shaped central incision allows the user to control the exit of the product, which is dosed out correctly. 
     For dense fluid products, the rectangular or semi-elliptic configuration that separates from the rest of the sheet after opening allows the product to be spread over a surface. 
     For liquid products, the triangular configuration that is created after opening allows the product to be dosed out in drops. For powdered or granular products, the “zig-zag” configuration allows, first of all, a controlled exit of the product and, then, its complete distribution.