Patent Publication Number: US-2018037348-A1

Title: Pack for tobacco articles provided with a sealed wrap with an inner pressure that is different from the atmospheric pressure and relative wrapping method

Description:
TECHNICAL FIELD 
     The present invention relates to a pack for tobacco articles provided with a sealed wrap and a relative wrapping method. 
     The present invention finds advantageous application to a packet of cigarettes provided with a sealed wrap, to which the following description will make explicit reference without thereby losing generality. 
     PRIOR ART 
     A packet of cigarettes normally comprises an inner wrap, which consists of a group of cigarettes wrapped in an inner sheet of wrapping material, and an outer cover, which encloses the inner wrap and can consist of an outer sheet of wrapping material folded around the inner cup-shaped wrap (soft type packet of cigarettes), or can consist of a rigid, hinged-lid box formed by folding a rigid blank around the inner wrap (rigid type packet of cigarettes). 
     In a conventional packet of cigarettes, the group of cigarettes is internally wrapped in a glue-free rectangular inner sheet of wrapping material made of metalized paper and is externally wrapped in a rectangular outer sheet of wrapping material which is stabilized by means of glueing. 
     The tobacco is very sensitive to external environmental effects, as being in contact with the atmosphere tends to alter its organoleptic characteristics due to the effect of moisture variations (tobacco can become too dry or can absorb too much moisture), both for the evaporation of the volatile substances with which the tobacco is impregnated (especially in the case of aromatized cigarettes with particular aromas such as cloves). To preserve the integrity of the cigarette tobacco, the packets of cigarettes are cellophane-wrapped, i.e. are covered with an external heat-sealed overwrap of waterproof plastic material. However, the external heat-sealed overwrap may not be sufficient to fully preserve the organoleptic characteristics of the tobacco contained in a packet of cigarettes, particularly when the packet of cigarettes is consumed after a certain lapse of time from the production thereof. Moreover, the outer overwrap is discharged the first time the packet is opened, and therefore the tobacco of the cigarettes contained in the pack comes in contact with the external environment; if the cigarettes contained in the packet are not quickly used after the first opening of the packet, the organoleptic characteristics of the remaining cigarettes may become degraded. 
     In the attempt to obviate the above described drawback, in U.S. Pat. No. 4,300,676A1 a rigid packet of cigarettes has been proposed, wherein the inner wrap is waterproof and consists of a sheet of wrapping material made of waterproof and heat-sealable material having a cigarette pull-out opening, which is closed by way of a reusable closing label. 
     DESCRIPTION OF INVENTION 
     The object of the present invention is to provide a pack for tobacco articles provided with a sealed wrap and a relative wrapping method, which pack and wrapping method will allow to more effectively maintain the organoleptic characteristics of the tobacco articles and, at the same time, being easy and inexpensive to manufacture. 
     According to the present invention, a pack for tobacco articles provided with a sealed wrap and a relative wrapping method are provided, as set forth in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described with reference to the accompanying drawings, which illustrate some non-limiting examples of embodiments, wherein: 
         FIG. 1  is a front perspective view and in a closed configuration of a packet of cigarettes made according to the present invention and comprising a sealed wrap provided with a passage hole controlled by a pneumatic valve; 
         FIG. 2  is a front perspective view of the packet of cigarettes of  FIG. 1  in a partially open configuration; 
         FIG. 3  is a front perspective view of the packet of cigarettes of  FIG. 1  in a fully open configuration; 
         FIG. 4  is a front perspective view of the sealed wrap of the packet of  FIG. 1 ; 
         FIG. 5  is a front perspective view of a group of cigarettes contained in the sealed wrap of  FIG. 4 ; 
         FIG. 6  is a front perspective view of a reinforcement element contained in the sealed wrap of  FIG. 4 ; 
         FIG. 7  is a plan view of a multilayer sheet of wrapping material used for producing the sealed wrap of  FIG. 4 ; 
         FIGS. 8 and 9  are two different sectional views of a passage hole and of a corresponding pneumatic valve formed in the multilayer sheet of wrapping material of  FIG. 7  respectively in a closed position and in an open position of the passage hole; 
         FIG. 10  is a sectional and exploded view of the multilayer sheet of wrapping material of  FIG. 7  at the passage hole and of the corresponding pneumatic valve of  FIGS. 8 and 9 ; 
         FIG. 11  is a plan view of the multilayer sheet of wrapping material of  FIG. 7  emphasizing two different types of adhesives interposed between two layers of the multilayer sheet of the wrapping material itself; 
         FIG. 12  is a plan view of an alternative of the multilayer sheet of wrapping material of  FIG. 7 ; 
         FIGS. 13 and 14  are two different sectional views of a passage hole and of a corresponding pneumatic valve formed in the multilayer sheet of wrapping material of  FIG. 12  in a closed position and in an open position of the passage hole, respectively; and 
         FIG. 15  is a front perspective view of an alternative embodiment of the packet of cigarettes of  FIG. 1  in a closed configuration; 
         FIG. 16  is a schematic and longitudinal section view of a detail of the packet of cigarettes of  FIG. 15 ; and 
         FIGS. 17, 18 and 19  are schematic and longitudinal section views of respective alternatives of the detail of  FIG. 16 . 
     
    
    
     PREFERRED EMBODIMENTS OF THE INVENTION 
     In  FIGS. 1, 2 and 3  number  1  denotes as a whole a rigid packet of cigarettes. The packet  1  of cigarettes comprises a cup-shaped outer container  2  made of cardboard or rigid paperboard and a sealed wrap  3  (better illustrated in  FIG. 4 ) housed inside the container  2 . The sealed wrap  3  encloses a parallelepiped shaped group  4  of cigarettes (better illustrated in  FIG. 5 ) and has at the top and in front a cigarette pull-out opening  5 ; the cigarette pull-out opening  5  is centrally arranged, being closed by an “open &amp; close” type sealing panel  6  involving a portion of a front wall of the sealed wrap  3  and a portion of a top wall of the sealed wrap  3 . The sealing panel  6  adheres normally to the part of the sealed wrap  3  arranged around the pull-out opening  5  to close (seal) the pull-out opening  5  and can be temporarily raised to free the pull-out opening  5 , and thus allowing the extraction of a cigarette through the pull-out opening  5  itself. 
     According to a different embodiment not illustrated, the cigarette pull-out opening  5  involves the entire upper portion of the sealed wrap  3 , the sealing panel  6  is absent, and the sealed wrap  3  is provided with a tear-off strip that allows removing a top portion of the sealed wrap  3  to free the pull-out opening  5 ; in other words, the first time the packet  1  of cigarettes is opened the user pulls the tear-off strip to remove an upper portion of the sealed wrap  3 , and therefore free the pull-out opening  5 . 
     The outer container  2  has an open top end  7  and is provided with a cup-shaped lid  8  which is hinged to the container  2  along a hinge  9  to rotate, with respect to the container  2 , between an open position (illustrated in  FIGS. 2 and 3 ) and a closed position (illustrated in  FIG. 1 ) of the open top end  7 . 
     The lid  8 , when in the closed position, gives the outer container  2  a rectangular parallelepiped shape having a top wall and a bottom wall parallel and opposite to each other, a front wall and a rear wall (in which the hinge  9  is formed) parallel and opposite to each other, and two lateral walls parallel and opposite to each other. Between the lateral walls and the front and rear walls four longitudinal edges are defined, while between the top and bottom walls and the front, rear and lateral walls eight transverse edges are defined. 
     As illustrated in  FIG. 6 , the sealed wrap  3  comprises a “U”-shaped reinforcement element  10 , which is made of cardboard or rigid paperboard (quite similar to the cardboard or rigid paperboard forming the outer container  2 ) and is arranged on the inside of the sealed wrap  3  in contact with the group  4  of cigarettes. The reinforcement element  10  comprises a substantially rectangular-shaped front wall  11  which is arranged in contact with a front wall of the group  4  of cigarettes and two lateral walls  12 , which are connected to opposite sides of the front wall  11  and are arranged in contact with the lateral walls of the group  4  of cigarettes. The front wall  11  has a “U”-shaped window which is arranged at the top, is defined by an edge  13  and facilitates the extraction of the cigarettes from the group  4  of cigarettes as it exposes a top area of the front wall of the group  4  of cigarettes. 
     The function of the reinforcement element  10  is to give greater rigidity and greater shape stability to the sealed wrap  3  in order to prevent the wrap  3  from collapsing on itself after extracting a part of the cigarettes contained in the same sealed wrap  3  thus complicating the extraction of the remaining cigarettes and complicating the opening and the subsequent re-closing of the sealing panel  6 . An additional function of reinforcement element  10  is to provide adequate mechanical protection to the cigarettes during the forming and handling of the sealed wrap  3 . Finally, another function of the reinforcement element  10  is to keep the lid  8  in the closed position, as the lid  8 , to shift from the closed position to the open position (and vice versa), must slightly deform the top and front part of the reinforcement element  10  in an elastic manner. 
     As illustrated in  FIG. 7 , the sealed wrap  3  is obtained by folding a rectangular-shaped heat-sealable sheet  14  of wrapping material, which is folded about the group  4  of cigarettes enclosed in the reinforcement element  10  and once folded is stabilized by means of heat-sealing (i.e. overlapping portions of the sheet  14  of wrapping material are connected together in a stable manner by heat-sealing). The sheet  14  of wrapping material has a “U”-shaped incision  15  which defines the pull-out opening  5 . The incision  15  can be a through incision from the beginning, i.e. from the beginning the incision  15  completely crosses through the thickness of the sheet  14  of wrapping material from side to side; in this embodiment, the air-tight seal of the sealed wrap  3  is ensured by the sealing panel  6  which completely covers the incision  15 . 
     Alternatively, the incision  15  can be a non-through incision i.e. initially the incision  15  involves only a part of the thickness of the sheet  14  of wrapping material leaving totally integral a remaining part of the thickness of the sheet  14  of wrapping material; in this embodiment, the incision  15  is initially a non-through incision with respect to the sheet  14  of wrapping material and becomes a through incision (by tearing the remaining initially integral part of the sheet  14  of wrapping material) the first time the sealed wrap  3  is opened, i.e. only the first opening of the sealed wrap  3  (that is, the first raising of the sealing panel  6 ) causes the complete tearing of the sheet  14  of wrapping material along the incision  15 . This embodiment, in which the incision  15  is initially a non-through incision, can be used both in conjunction with the sealing panel  6 , and in the absence of the sealing panel  6 , since the air-tight seal of the sealed wrap  3  is ensured by the fact that the incision  15  is initially a non-through incision; for example, in the absence of the sealing panel  6  a gripping tab can be glued to the pull-out opening  5  for raising the sheet  14  of wrapping material inside the incision  15 , or the pull-out opening  5  can be glued to the inner surface of the front wall of the lid  8  to obtain an “automatic” opening of the pull-out opening  5  in combination with the opening of the lid  8 . 
     Furthermore, the rectangular-shaped sealing panel  6  is glued to the sheet  14  of wrapping material and completely covers the incision  15  (i.e. the pull-out opening  5 ). Between the sealing panel  6  and the sheet  14  of wrapping material a pressure-sensitive repositionable adhesive  16  (i.e. that does not dry) is interposed, that allows to separate the sealing panel  6  from the sheet  14  of wrapping material also after a long period of time, and then to reunite the sealing panel  6  to the sheet  14  of wrapping material for numerous times. 
     The presence of the pressure-sensitive repositionable adhesive (i.e. which does not dry) between the sealing panel  6  and the sheet  14  of wrapping material causes a temporary glueing (that is, separated in use) between the portion of the sheet  14  of wrapping material surrounding the incision  15  (that is, surrounding the pull-out opening  5 ) and the sealing panel  6  so as to normally keep the sealing panel  6  in contact with the sheet  14  of wrapping material to close (seal) the pull-out opening  5 . Moreover, the presence of the pressure-sensitive repositionable adhesive  16  (i.e. which does not dry) between the sealing panel  6  and the sheet  14  of wrapping material causes the functionally permanent glueing (that is, never separated also in use) of the portion of the sheet  14  of wrapping material, enclosed by the incision  15  (i.e. at the pull-out opening  5 ), to the sealing panel  6 ; therefore, when the sealing panel  6  is raised from the sheet  14  of wrapping material the portion of the sealing panel  6  enclosed by the incision  15  (that is, at the extraction opening  5 ) is raised together with the sealing panel  6  freeing the pull-out opening  5 . Obviously, it is also possible to use non-separable permanent adhesive (i.e. that dries) which is interposed between the sealing panel  6  and the sheet  14  of wrapping material inside the incision  15  (that is, at the pull-out opening  5 ) in order to strengthen the mechanical connection between these two parts; the presence of non-separable permanent adhesive between the sealing panel  6  and the sheet  14  of wrapping material inside the incision  15  (that is, at the pull-out opening  5 ) is required when the incision  15  is initially a non-through incision to overcome the tear-off resistance of the initially non-through incision  15 . 
     The sealing panel  6  is provided with two gripping tabs  17 , each of which is free from pressure-sensitive repositionable adhesive  16  (i.e. that does not dry) on the side facing the sheet of packing material  14  (that is, on the surface in front of the sheet  14  of wrapping material) and it is arranged near the pull-out opening  5  and below the pull-out opening  5  itself. Each gripping tab  17  is suited to facilitate the grip of the sealing panel  6  when the sealing panel  6  itself is raised; in other words, to raise the sealing panel  6 , a user can easily grip a gripping tab  17 , which is in no way fixed to the sheet  14  of wrapping material in contrast to the rest of the sealing panel  6 . 
     As illustrated in  FIG. 4 , the sealed wrap  3  comprises a passage hole  18 , which is formed through a front wall of the sealed wrap  3  to allow suction of part of the air contained inside the sealed wrap  3  so as to depressurize the sealed wrap itself. In the embodiment illustrated in  FIG. 4 , the passage hole  18  is formed through the front wall of sealed wrap  3 , but it is clear that the passage hole  18  can be formed in any other wall (top, bottom, lateral, rear) of the sealed wrap  3 ; in any case, it is preferable that the passage hole  18  is formed at the reinforcement element  10 , i.e. in an area of the sealed wrap  3  resting on the underlying reinforcement element  10 . In fact, during the suction of part of the air contained inside the sealed wrap  3 , a suction device rests with a certain mechanical pressure on the sealed wrap  3  around the passage hole  18  and therefore the presence of the underlying reinforcement element  10  at the passage hole  18  prevents the mechanical pressure exerted by the suction device from damaging the cigarettes contained inside the sealed wrap (i.e. the reinforcement element  10  protects the cigarettes contained inside the sealed wrap  3  from the mechanical pressure exerted by the suction device). 
     Furthermore, the sealed wrap  3  comprises a one-way pneumatic valve  19  that overlaps the passage hole  18  and has the function of keeping the passage hole  18  normally isolated from the external environment in order to not allow any gas passage between the sealed wrap  3  and the external environment. The pneumatic valve  19  is normally closed (i.e. normally seals air-tight the passage hole  18 , isolating the passage hole  18  from the outside environment) and is temporarily open (i.e. allowing free communication between the passage hole  18  and the external environment) only and just during the suction step of the air contained inside the sealed wrap  3  to depressurize the sealed wrap  3  itself. 
     As illustrated in  FIGS. 8-11 , the pneumatic valve  19  comprises a valve element  20 , which is movable between a closed position (illustrated in  FIGS. 8 and 10 ) in which the passage hole  18  is sealed air-tight, isolating the passage hole  18  from the external environment, and an open position (illustrated in  FIG. 9 ) wherein it allows free communication between the passage hole  18  and the external environment. 
     As illustrated in  FIGS. 8 and 9 , the sheet  14  of wrapping material is of multilayer type and comprises an inner layer  21  of plastic material (of thermoplastic type to be heat-sealable) and an outer layer  22  of plastic material (of thermoplastic type to be heat-sealable) which overlap and are glued to each other and both extend seamless over the whole surface of the sheet  14  of wrapping material. Between the two layers  21  and  22  a non-separable permanent adhesive  23  is interposed, that, as illustrated in  FIG. 11 , extends over the whole sheet  14  of wrapping material except for the area in which the valve element  20  is located (i.e. except for the area where the pneumatic valve  19  is located); the permanent adhesive  23  is an adhesive that dries and therefore once dried (i.e. shortly after its application) does not allow any separation (if not after a final and non reassemblable breakage) between the two layers  21  and  22 . In the area where the valve element  20  is located (i.e. the area in which the pneumatic valve  19  is located), between the two layers  21  and  22  a pressure-sensitive repositionable adhesive  24  (i.e. which does not dry and therefore of the same type of the repositionable adhesive  16  used for the sealing panel  6 ) is interposed that allows even after a long time to locally separate the two layers  21  and  22  and then to reunite the two layers  21  and  22  for numerous times. 
     As better illustrated in  FIGS. 8, 9 and 10 , the passage hole  18  is formed only through the inner layer  21  of the sheet  14  of wrapping material; i.e. the passage hole  18  passes through the inner layer  21  of the sheet  14  of wrapping material and does not involve in any way the outer layer  22  of the sheet  14  of wrapping material. Furthermore, the valve element  20  of the pneumatic valve  19  consists of a portion of the outer layer  22  (and only of the outer layer  22 ) which is separated from the remaining part of the outer layer  22  by a “U”-shaped through incision  25  and is connected to the underlying inner layer  21  by means of the repositionable adhesive  24 . In the embodiment illustrated in the accompanying figures the “U”-shaped through incision  25  forms a sharp edge at the cusp (as illustrated in  FIG. 7 ), but according to alternative and completely equivalent embodiments the “U”-shaped through incision  25  can have a rounded shape at the cusp, or can be shaped as a fractured line formed by the union of several straight segments angled one with respect to the other. 
     Usually, the repositionable adhesive  24  which is located at the pneumatic valve  19  keeps the valve element  20  of the pneumatic valve  19  in close contact with the underlying layer  21  of the inner sheet  14  of wrapping material by sealing air-tight the passage hole  18 , i.e. by isolating the passage hole  18  from the external environment (as illustrated in  FIG. 8 ). When an adequate uplifting force (typically by suction effect or by means of mechanical action) is applied to the valve element  20  of the pneumatic valve  19 , the valve element  20  of the pneumatic valve  19  is raised from the underlying inner layer  21  of the sheet  14  of wrapping material (and therefore the repositionable adhesive  24  stops its binding action) allowing free communication between the passage hole  18  and the external environment (as illustrated in  FIG. 9 ); when the uplifting force acting on the valve element  20  of the pneumatic valve  19  stops, the valve element  20  rests again on the underlying inner layer  21  of the sheet  14  of wrapping material (as illustrated in  FIG. 8  and optionally with the aid of a mechanical presser) causing a new closing of the pneumatic valve  19  due to the binding action of the repositionable adhesive  24 . 
     In the embodiment described above, there is only one passage hole  18  having relatively large sizes and the pneumatic valve  19  has a single valve element  20  which is coupled directly to the passage hole  18  (i.e. overlaps the passage hole  18 ). According to an alternative and perfectly equivalent embodiment, there are multiple passage holes  18  having smaller sizes and the pneumatic valve  19  has more valve elements  20 , each of which is coupled directly to a corresponding passage hole  18  (i.e. overlaps the passage hole  18 ). According to a further and perfectly equivalent embodiment, there is only one passage hole  18  having relatively large sizes and the pneumatic valve  19  has more valve elements  20 , each of which is arranged around the passage hole  18  (i.e. the valve elements  20  are uniformly distributed around the passage hole  18 ). 
     In the embodiment described above, the adhesive  24  which is located at the pneumatic valve  19  is a pressure-sensitive repositionable adhesive (i.e. which does not dry); in this embodiment, the pneumatic valve  19  is multi-purpose, i.e. can be used many times as it is possible to switch several times from the closed position to the open position and vice versa. According to an alternative embodiment, the adhesive  24  which is located at the pneumatic valve  19  is an adhesive which is initially inactive and is activated by heat, i.e. is an adhesive that at the first application does not cause any type of glueing between the two layers  21  and  22  of sheet  14  of wrapping material and which can be activated by heating in order to cause permanent glueing (i.e. no longer separable if not by non reassemblable breakage) between the two layers  21  and  22  of sheet  14  of wrapping material; in this embodiment, the pneumatic valve  19  is disposable, or may be used only once because once the adhesive  24  is activated by heating it is no longer possible to re-open the pneumatic valve  19  itself. 
     As previously stated, the passage hole  18  is formed through the front wall of the sealed wrap  3 , and then overlaps the front wall  11  of the reinforcement element  10 . The reinforcement element  10  may be free from holes at the passage hole  18 , as in any case by sucking air through the passage hole  18  the air reaches the passage hole  18  flowing in the space formed between the inner surface of the sealed wrap  3  and the outer surface of the reinforcement element  10 ; however, in this embodiment it is necessary to apply a larger suction depressurization to overcome the pressure loss generated by the “tortuous” path followed by the air inside the sealed wrap  3  in order to reach the passage hole  18 . According to a preferred embodiment illustrated in dashed lines in  FIG. 6 , the front wall  11  of the reinforcement element  10  has a through hole  26 , which is arranged at the passage hole  18  (i.e. is aligned with the passage hole  18 ) and it allows a more direct airflow inside the sealed wrap  3  towards the passage hole  18 . 
     According to a preferred embodiment illustrated in  FIG. 6  and in  FIGS. 8, 9 and 10 , around the through hole  26  of the reinforcement element  10  a non-separable permanent adhesive  27  is applied which causes a locally permanent glueing between the sheet  14  of wrapping material and the underlying reinforcement element  10  (i.e. between the bottom face of the inner layer  21  of the sheet  14  of wrapping material and the top face of the front wall  11  of the reinforcement element  10 ). The function of permanent adhesive  27  is to bind the inner layer  21  of the reinforcement element  10  to the underlying sheet  14  of wrapping material at the pneumatic valve  19  (i.e. around the through hole  26  of the reinforcement element  10 ) in such a way that when an uplifting force is applied to the valve element  20  of the pneumatic valve  19 , only the valve element  20  of the pneumatic valve  19  raises from the underlying layer  21  of the inner sheet  14  of wrapping material. In other words, in the absence of the permanent adhesive  27  when an uplifting force is applied to the valve element  20  of the pneumatic valve  19  the entire sheet  14  of wrapping material (i.e. both the valve element  20  of the pneumatic valve  19 , and the underlying inner layer  21 ) could be raised without therefore causing the desired separation between the valve element  20  of the pneumatic valve  19  and the underlying inner layer  21  of the sheet  14  of wrapping material; whereas, the presence of the permanent adhesive  27  mechanically binds the inner layer  21  of the sheet  14  of wrapping material to the underlying reinforcement element  10  preventing the inner layer  21  of the sheet  14  of wrapping material from raising up and thus allowing the pneumatic valve  19  to open properly when an uplifting force is applied to the valve element  20  of the pneumatic valve  19 . 
     According to a preferred, but non-limiting, embodiment, the passage hole  18  is formed through the inner layer  21  of the sheet  14  of wrapping material before uniting together the two layers  21  and  22  of sheet  14  of wrapping material; in the same way, the through incision  25  which defines the valve element is formed through the outer layer  22  of the sheet  14  of wrapping material before uniting together the two layers  21  and  22  of sheet  14  of wrapping material. In this way, forming the passage hole  18  and the through incision  25  is extremely simple and can be performed by routine mechanical operations. It is important to note that when the two layers  21  and  22  of the sheet  14  of wrapping material are overlapped, a high precision is not required in the relative positioning between the passage hole  18  and the through incision  25  that defines the valve element  20 , as small deviations do not alter in any way the functionality of the pneumatic valve  19 . Alternatively, the passage hole  18  and the through incision  25  can be made on the sheet  14  of wrapping material after the two layers  21  and  22  are united together; in this case, it is necessary to use laser processing that allows the high precision cutting of only part of the overall thickness of the sheet  14  of wrapping material. 
     In the embodiment illustrated in  FIGS. 7-11 , the one-way pneumatic valve  19  allows only a flow of gas from inside the sealed wrap  3  towards the external environment to depressurize the sealed wrap  3  itself, i.e. the one-way pneumatic valve  19  allows only to suck some of the air contained inside the sealed wrap  3  to depressurize the sealed wrap  3  itself. Therefore, the one-way pneumatic valve  19  is used to impart an inner pressure lower than atmospheric pressure (i.e. environmental pressure) to the sealed wrap  3 ; in particular, the one-way pneumatic valve  19  is used to suck part of the air contained inside the sealed wrap  3  and therefore depressurize the sealed wrap  3  itself. Preferably the vacuum inside the sealed wrap  3  (i.e. the pressure variation between the inside of the sealed wrap  3  and the atmospheric pressure) is less than 0.05 bar and generally comprised between 0.01 bar and 0.02 bar. It is important to note that the greater the mechanical protection of the group  4  of cigarettes is, as ensured by the reinforcement element  10 , the greater the vacuum inside the sealed wrap  3  can be; to increase the mechanical protection of the group  4  of cigarettes ensured by the reinforcement element  10  (therefore to increase the vacuum inside the sealed wrap  3 ), the reinforcement element  10  could also be provided with a rear wall which gives the reinforcement element  10  a tubular shape having overall a greater mechanical strength. 
     In the alternative embodiment illustrated in  FIGS. 12-14 , the one-way pneumatic valve  19  is “inverted”, i.e. allows only a flow of gas from the external environment towards the inside of the sealed wrap  3  to pressurize the sealed wrap  3 , i.e. the one-way pneumatic valve  19  allows only to pump a gas (typically inert such as nitrogen) inside the sealed wrap  3  to pressurize the sealed wrap  3 . Therefore, the one-way pneumatic valve  19  is used to impart an inner pressure higher than the atmospheric pressure (i.e. environmental pressure) to the sealed wrap  3 . Typically, in the sealed wrap  3  an inert gas is pumped (for example nitrogen, argon or carbon dioxide) until the desired overpressure is reached; sterilizing and/or aromatizing compounds can be added to the inert gas (for example comprising menthol aroma, tobacco aroma, coffee aroma, anise aroma). Preferably the pressurization inside the sealed wrap  3  (i.e. the pressure variation between the inside of the sealed wrap  3  and the atmospheric pressure) is less than 0.15 bar and generally comprised between 0.05 bar and 0.10 bar. 
     In the embodiment illustrated in  FIGS. 7-11 , the passage hole  18  is formed only through the inner layer  21  of the sheet of wrapping material; i.e. the passage hole  18  passes through the inner layer  21  of the sheet  14  of wrapping material and does not involve in any way the outer layer  22  of the sheet  14  of wrapping material. Whereas, in the embodiment illustrated in  FIGS. 7-11 , the passage hole  18  is formed only through the outer layer  22  of the sheet  14  of wrapping material; i.e. the passage hole  18  passes through the outer layer  22  of the sheet  14  of wrapping material and does not involve in any way the inner layer  21  of the sheet  14  of wrapping material. 
     In the embodiment illustrated in  FIGS. 7-11 , the valve element  20  of the pneumatic valve  19  consists of a portion of the outer layer  22  (and only of the outer layer  22 ) which is separated from the remaining part of the outer layer  22  by a “U”-shaped through incision  25  and is connected to the underlying inner layer  21  by means of the repositionable adhesive  24 . Whereas, in the embodiment illustrated in  FIGS. 7-11 , the valve element  20  of the pneumatic valve  19  consists of a portion of the inner layer  21  (and only the inner layer  21 ) which is separated from the remaining part of the inner layer  21  by the “U”-shaped through incision  25  and is connected to the overlying outer layer  22  by means of the repositionable adhesive  24 . 
     In the embodiment illustrated in  FIGS. 7-11 , the outer layer  22  of the sheet  14  of wrapping material has a thickness lesser than the thickness of the inner layer  22  as, in this way, the valve element  20  of the pneumatic valve  19  has a lower mechanical inertia and a greater ease of deformation that make operating thereof more effective. Similarly, in the embodiment illustrated in  FIGS. 7-11  the outer layer  22  of the sheet  14  of wrapping material has a thickness greater than the thickness of the inner layer  21 . 
     In the embodiments described above, the depressurization or the pressurization of the sealed wrap  3  are obtained by means of corresponding pneumatic valves  19  through which a gas passage (out-coming or incoming) is obtained through the sealed wrap  3 . According to a different embodiment, the sealed wrap  3  is completely free from pneumatic valves  19  and the depressurization or the pressurization of the sealed wrap  3  are obtained by means of an active element that is inserted inside the sealed wrap  3  before the sealed wrap  3  itself is completely closed and that slowly absorbs (i.e. in a few seconds, a few minutes or a few hours) a quantity of the gases contained inside the sealed wrap  3  (to depressurize the sealed wrap  3 ) or slowly releases (i.e. in a few seconds, a few minutes or a few hours) gases in the sealed wrap  3  (to pressurize the sealed wrap  3 ). 
     For example the active element could consists of an inert gas in the liquid state (liquid nitrogen, liquid argon) or in the solid state (dry ice i.e. solid carbon dioxide) that is initially cold (i.e. considerably colder than environmental temperature and at a below zero temperature) and by warming (due to the environmental heat), inside the sealed wrap  3 , vaporizes thereby increasing the inner pressure of the sealed wrap  3  itself. In this case the active element is inserted in the sealed wrap  3  immediately before the final sealing (i.e. immediately upstream from the welder that performs the final sealing). 
     Alternatively, the active element could consist of a substance which, in contact with oxygen, oxidize (i.e. combines with oxygen) by means of a chemical reaction which can generate a greater volume of gas with respect to the initial state (to pressurize the sealed wrap  3 ) or can produce a smaller volume of gas with respect to the initial state (to depressurize the sealed wrap  3 ); said embodiment allows to repeat pressurization/depressurization of the sealed wrap  3  at each opening (and subsequent closing) of the sealed wrap  3 : in fact at every opening (and subsequent closing) of the sealed wrap  3  new oxygen enters inside the sealed wrap  3  allowing to repeat the chemical reaction that pressurizes/depressurizes the sealed wrap  3 . For example, the active element may comprise the so called “oxygen scavengers”, i.e. elements capable of spontaneously oxidizing and thus capture the molecular oxygen content inside the sealed wrap  3  (for example, oxygen scavengers most used in the food sector are iron based). In other words, an oxygen scavenging element is inserted inside the sealed wrap  3  that after the air-tight closing of the sealed wrap  3  and slowly (i.e. in a time frame of minutes or tens of minutes), consumes at least part of the molecular oxygen contained inside the sealed wrap  3  itself thus reducing the inner pressure of the sealed wrap  3 . In this case, the active element can be contained in a separate insertion which is introduced inside the sealed wrap  3 , or it can be carried by the reinforcement element  10  and/or by the inner surface of the sheet  14  of wrapping material (in this case, the oxygen scavenging element is applied by means of surface treatment, also by nano-technology, of the reinforcement element  10  and or of the inner surface of the sheet  14  of wrapping material). 
     According to a possible embodiment, in the sealed wrap  3  a volatile aromatic substance (for example tobacco aroma) can be inserted which is progressively released inside the sealed wrap  3  and comes out of from the sealed wrap  3  the first time the sealed wrap  3  is opened. Preferably (but not exclusively), the volatile aromatic substance is inserted in the sealed wrap  3  when the inner pressure of the sealed wrap  3  is higher than the atmospheric pressure (i.e. environmental pressure), because in this way the first time the sealed wrap  3  is opened a significant part of the gases contained inside the sealed wrap  3  comes out due to the inner overpressure of the sealed wrap  3  thus diffusing around the packet  1  of cigarettes a significant quantity of volatilized aromatic substance; consequently, the first time the sealed wrap  3  is opened the user perceives a very strong out-coming aroma from the packet of cigarettes, receiving a highly positive sensation. In other words, the first time the sealed wrap  3  is opened the inner overpressure of the sealed wrap  3  operates as an efficient and effective diffuser of the volatilized aromatic substance contained in the sealed wrap  3 . This solution is particularly advantageous when the sealed wrap  3  receives not a group  4  of conventional cigarettes but a group of other tobacco articles which have a limited (if compared with the fragrance of conventional cigarettes) or totally absent fragrance. 
     The volatile aromatic substance can be pumped into the sealed wrap  3  in a gaseous state when overpressure is obtained or can be inserted in the sealed wrap  3  in a liquid or solid state to obtain a volatilization (relatively slow) of the aromatic substance in the sealed wrap  3 . For example, the aromatic substance may be sprayed in a liquid state on the sheet  14  of wrapping material immediately before folding the sheet  14  of wrapping material around the group  4  of cigarettes, it can be impregnated into the reinforcement element  10  (which, being made of cardboard, is permeable and particularly appropriate for absorbing the volatile aromatic substance in the liquid state), or it may be impregnated into a permeable support that is coupled to the group  4  of cigarettes before folding the sheet  14  of wrapping material around group  4  of cigarettes. 
     When the sealed wrap  3  is internally provided with a different pressure than the atmospheric pressure (i.e. environmental pressure), the sealed wrap  3  itself undergoes a deformation due to the differential between its inner pressure and the atmospheric pressure (i.e. the pressure of the external environment): in particular when the sealed wrap  3  is depressurized the atmospheric pressure forces the sealed wrap  3  to adhere to its own content (i.e. to the group  4  of cigarettes) by compressing its content, whereas when the sealed wrap  3  is pressurized the sealed wrap  3  itself inflates. Said deformations of the sealed wrap  3  due to the pressure differential between the inner sealed wrap  3  and atmospheric pressure could give the sealed wrap  3  itself a relatively unpleasant look and therefore it may be convenient to limit said deformations. 
     One possibility for limiting the deformations of the sealed wrap  3  due to the pressure differential is to mechanically bind (typically by means of glueing but also possibly by heat-sealing) some parts of the sealed wrap  3  (obviously externally to the pull-out opening  5 ) to the reinforcement element  10  and/or to the outer container  2  (obviously not to the lid  8 ); in this way the effective length of the sealed wrap  3  is reduced and in this way the possibility of deformation of the sealed wrap  3  is significantly reduced. For example the front wall (externally to the pull-out opening  5 ) and/or the lateral walls of the sealed wrap  3  may be mechanically bound (glued or heat sealed) respectively to the front wall  11  and to the lateral walls  12  of the reinforcement element  10 ; in addition or alternatively, the front wall, the lateral walls and/or the rear wall of the sealed wrap  3  can be mechanically bound (glued or heat sealed) to the corresponding walls of the outer container  2 . In the case in which the reinforcement element  10  comprises also a top wall, the top wall of the sealed wrap  3  (externally of the pull-out opening  5 ) can be mechanically bound (glued or heat sealed) to the top wall of the reinforcement element  10 . 
     A further possibility to limit the deformations of the sealed wrap  3  due to the pressure differential is to thermo-shrink the sealed wrap  3  after the construction of the sealed wrap  3  is completed; in this way the effective length of the sealed wrap  3  is reduced and therefore the possibility of deformation of the sealed wrap  3  is reduced. Obviously, the thermo-shrinkage of the sealed wrap  3  must be limited to not overly compress the group of cigarettes  4 , i.e. to avoid damaging the group  4  of cigarettes; in this regard it should be noted that the reinforcement element  10  which embraces the group  4  of cigarettes provides a certain mechanical protection to cigarettes and thus allows to slightly heat-shrink the sealed wrap  3  without taking the risk of damaging the group  4  of cigarettes. To increase the mechanical protection of the group  4  of cigarettes, the reinforcement element  10  could also have a rear wall which gives the reinforcement element  10  itself a tubular shape having an overall greater mechanical strength. 
     As previously mentioned, when the sealed wrap  3  has an inner pressure different from the atmospheric pressure (i.e. environmental pressure), the sealed wrap  3  itself undergoes a deformation by effect of the differential between its inner pressure and the atmospheric pressure; said deformation of the sealed wrap  3  due to the pressure differential is completely invisible to the user when the lid  8  is closed (i.e. before opening the packet  1  of cigarettes). As illustrated in  FIG. 15 , to make the deformation of the sealed wrap  3  visible from the outside also when the lid  8  is closed (i.e. before opening the packet  1  of cigarettes), it is possible to form a through hole  28  on the outer container  2  (or possibly on lid  8 ) displaying a portion of the underlying sealed wrap  3 . 
     According to a possible embodiment, when the sealed wrap  3  is depressurized (i.e. when the sealed wrap  3  has an inner pressure lower than atmospheric pressure), the portion of the reinforcement element  10  arranged at the through hole  28  may be embossed so as to have a pattern (alphabet letter, symbol, logo . . . ) in relief that is emphasized (i.e. is clearly visible from the outside of the sealed wrap  3 ) thanks to the fact that the sealed wrap  3  adheres to the reinforcement element  10  due to the depressurization; highlighting in this way the fact that the sealed wrap  3  is depressurized. Alternatively, when the sealed wrap  3  is depressurized (i.e. when the sealed wrap  3  has an inner pressure lower than atmospheric pressure), the reinforcement element  10  has a further through hole, which has the same shape, size and position of the through hole  28  so as to perfectly overlap the through hole  28 ; in this way, at the through hole  28 , the sealed wrap  3  adheres to the underlying cigarettes of group  4  of cigarettes, highlighting the fact that the sealed wrap  3  is depressurized. 
     According to a possible embodiment illustrated in  FIGS. 16-19 , when the sealed wrap  3  is pressurized (i.e. when the sealed wrap  3  has an inner pressure higher than the atmospheric pressure), the sealed wrap  3  has a deformable portion  29  that is arranged at the through hole  28  and is suited to deform (inflate) due to the inner pressure of the sealed wrap  3  so as to project outwards from the remaining part of the sealed wrap  3 . According to the embodiment illustrated in  FIG. 16 , the deformable portion  29  consists of a part of the sheet  14  of wrapping material that is locally weakened; for example, the sheet  14  of wrapping material is locally weakened by means of an inelastic deformation induced by a mechanical strut before the sheet  14  of wrapping material is folded around the group  4  of cigarettes. According to the embodiments illustrated in  FIGS. 17, 18 and 19 , the deformable portion  29  is initially separate and independent of the sheet  14  of wrapping material and is applied (glued or heat sealed) to the sheet  14  of wrapping material generally before the sheet  14  of wrapping material is folded around group  4  of cigarettes; at the deformable portion  29  of the sealed wrap  3  (i.e. the sheet  14  of wrapping material forming the sealed wrap  3 ) has a through hole  30  that connects the deformable portion  29  with the inside of the sealed wrap  3  to allow the deformable portion  29  to deform as a function of the pressure inside the sealed wrap  3  (i.e. allows the deformable portion  29  to share the same inner pressure of the sealed wrap  3 ). 
     According to the embodiment illustrated in  FIG. 19 , around the through hole  28  the outer container  2  has a deformation (made for example by means of embossing) which curves inwards (i.e. towards the sealed wrap  3 ) the outer container  2 ; in other words, around the through hole  28  the outer container  2  has an inward recess (i.e. towards the sealed wrap  3 ). Said recess of the outer container  2  around the through hole  28  allows to put greater emphasis on the deformable portion  29  of the sealed wrap  3 . 
     According to a possible embodiment, the outer part and/or the inner part of the deformable portion  29  may incorporate a diffraction grating that modifies the look perceived on the outside (for example the color) as a function of its geometric conformation (or as a function of its shape); in this way when the inner pressure of the sealed wrap  3  is higher than the atmospheric pressure, the deformable portion  29  is “inflated”, and therefore appears on the outside having a certain aspect (for example a green colouring to indicate the integrity of the sealed wrap  3 ), while when the inner pressure of the sealed wrap  3  is lower than the atmospheric pressure the deformable portion  29  is “deflated” and therefore appears on the outside having a different aspect (for example a red colouring to indicate that the sealed wrap  3  has been open and therefore pressurization has been lost). 
     In the non-limiting embodiment illustrated in the accompanying figures and described above, the pack of the present invention contains a group  4  of cigarettes; however, the pack of the present invention may contain any other type of tobacco articles such as cigars, electrical or electronic cigarettes (i.e. cigarettes that generate an aerosol without combustion), cartridges and refills for electronic cigarettes, new-generation cigarettes. 
     The sealed wrap  3  described above has various advantages. 
     First, the sealed wrap  3  allows to preserve more effectively the organoleptic characteristics of the tobacco articles contained within thanks to the fact that the inner pressure of the sealed wrap  3  is different from the atmospheric pressure (i.e. the environmental pressure). In fact, when the inner pressure of the sealed wrap  3  is different from the atmospheric pressure the tobacco articles contained in the sealed wrap  3  are kept in a low oxygen content environment (because part of the oxygen was extracted during the depressurization or because part of the oxygen has been replaced by an inert gas during pressurization). 
     Furthermore, the sealed wrap  3  described above is also simple and inexpensive to produce, since it is relatively easy to depressurize/pressurize the sealed wraps also in an existing packing machine.