Patent Publication Number: US-2009218247-A1

Title: Flexible moisture-barrier packages and methods of producing same

Description:
FIELD AND BACKGROUND OF THE INVENTION 
     The present invention relates to flexible moisture-barrier packages, sometimes called pouches, for packaging products which are sensitive to moisture. The invention also relates to methods of producing such packages. 
     Many products are sensitive to moisture and have shelf lives which are greatly influenced by the storage conditions of humidity, temperature, oxygen, etc. Various means have been developed to improve the storage conditions of such products and thereby to prolong their shelf life. For example, many packages include desiccants for absorbing moisture (water vapor), and/or gas absorbents for absorbing gases, in order to prolong the shelf life of the packaged product. In other techniques, nitrogen gas, argon gas, etc., is introduced into the package of the product, or air is withdrawn from the interior of the package to produce a vacuum therein. Humidity indicators are also introduced into the interior of the package to allow visual monitoring of the humidity within the package. 
     Metal foil, particularly aluminum foil, is widely used in flexible barrier packaging. The barrier properties of aluminum foil, both for moisture and for gases, are extremely high and very cost effective. However, aluminum foil of less than 20 microns includes small pinholes which substantially reduce the barrier level of such foils. Aluminum foils are also very sensitive to folding and cracking, which may substantially increase the permeability of the foil with respect to air, humidity (water vapor) and gases. 
     Transparent humidity-barrier films are also known including transparent polymer substrates having vacuum-coated moisture-barrier layers thereover, such as alumina, silicon oxides, etc. However, the barrier-capability of such films, particularly with respect to humidity, is significantly lower than that of aluminum foil barrier films. 
     Many constructions of packages have been developed to include desiccants for absorbing moisture and/or moisture indicators to indicate whether moisture has penetrated into the interior of the package. For example, U.S. Pat. No. 5,293,996 describes a package including separate compartments for humidity indicators and desiccants; whereas U.S. Pat. No. 5,875,892 describes a package in which a humidity indicator is secured to the package and viewable through a transparent window. Both types of packages require the introduction of the moisture indicator, at the time of producing the package which complicates the production process. Moreover, the production of such a package for use with one type of product, requiring a specific moisture indicator, would not be usable with respect to other products requiring a different type of moisture indicator and/or desiccant. 
     In addition, many products to be packaged are not only sensitive to moisture, but are also sensitive to static electricity and/or electromagnetic fields. Accordingly, it is desirable, in many applications, to include anti-static and/or electromagnetic (EMI) shielding properties to the packaging, to enable the packaging material to dissipate electrostatic charges. Such anti-static coatings are generally applied to the outer faces of the packages; since anti-static coatings are not easily bondable to polymers, and therefore present problems when applied to the inner faces of the two polymer sheets to be bonded together to form the package. 
     OBJECTS AND BRIEF SUMMARY OF THE PRESENT INVENTION 
     An object of the present invention is to provide a flexible moisture-barrier package having advantages in one or more of the above respects. More particularly, an object of the present invention is to provide a flexible moisture-barrier package which can be produced in volume and at low cost, which can be used for a wide variety of products requiring different moisture-indicators, desiccants, or the like, and which can use standard packing-making or pouch-making machines. Yet another object of the invention is to provide laminate containing a metal foil, particularly aluminum foil, layer providing a high moisture-barrier capability and a low sensitivity to folding and cracking. A further object is to provide a transparent-polymer multi-layer sheet also having a high moisture-barrier capability. 
     A still further object of the present invention is to provide a method of making such flexible moisture-barrier packages which method is susceptible for volume-production at low cost and can also be used for applying anti-static properties to the packages. 
     According to one aspect of the present invention, there is provided a flexible package for a product sensitive to moisture, comprising: a front flexible sheet having moisture-barrier properties; and a back flexible sheet having moisture-barrier properties joined along its peripheral edges to the peripheral edges of the front flexible sheet except for one edge thereof to define a compartment allowing the introduction of the product and then the sealing of the package by bonding the unjoined edges; wherein at least a section of the front flexible sheet having moisture-barrier properties is optically transparent, such as to permit a moisture-indicator, a desiccant, a bar code label, and/or an RFID (radio frequency identification device) to be introduced with the product into the interior of the package before bonding the one edge of the two sheets, and to be optically observed through the transparent section after the package has been sealed by bonding said one edge. 
     According to further features in the described preferred embodiments, the back flexible sheet and the front flexible sheet are of an opaque material, particularly a laminate containing aluminum foil, having moisture-barrier properties, except for the transparent section of the front flexible sheet, which is of an optically transparent material having moisture-barrier properties. 
     In one described preferred embodiment, the transparent section of the front flexible sheet extends across the complete width of the front flexible sheet. 
     In a second described preferred embodiment, the transparent section of the front flexible sheet includes at least one transparent window formed in the front flexible sheet, the window being of smaller width and length than the width and length of the front flexible sheet. In the described embodiment, the transparent section of the front flexible sheet includes a plurality of windows such as to permit a moisture indicator, as well as a bar code label, and/or a radio-frequency identification device (RFID) also to be introduced with the product into the interior of the package before sealing and to be optically observed after sealing. 
     In a third described embodiment, the front flexible sheet is optically transparent for its complete surface area. 
     According to further features in the described preferred embodiments, the back flexible sheet includes a polymer substrate, a vacuum-coated moisture barrier layer thereover, and a metal foil of less than 20 microns over the moisture-barrier layer. The metal foil is preferably of aluminum, and the moisture-barrier layer is preferably a vacuum-coated metal or oxide. Such a construction has been found to effectively avoid the pinhole problem with aluminum foils, even when extremely thin foils are used. In the described preferred embodiments, the aluminum foil is less than 20 microns in thickness, preferably about six microns, but may even be less when thinner foils become available. 
     According to further features in the described preferred embodiments, the transparent section of the front flexible sheet is a multi-layer lamination including a first transparent polymer substrate having a first vacuum-coated moisture-barrier layer bonded to a second transparent polymer substrate having a second vacuum-coated moisture-barrier layer. It is contemplated that the multi-layer lamination may include even a third transparent polymer substrate having a third vacuum-coated moisture-barrier layer. Such a multi-layer construction produces a moisture barrier which is substantially superior to the single layer constructions heretofore used. 
     According to a still further feature included in a described preferred embodiments, the inner faces of the front and back flexible sheets are coated with an anti-static coating to dissipate electrical charges, and/or to provide electromagnetic shielding. 
     According to another aspect of the present invention, there is provided a flexible package comprising: a front flexible sheet having moisture-barrier properties; and a back flexible sheet having moisture-barrier properties joined along its peripheral edges to the peripheral edges of the front flexible sheet except for one edge thereof to define a compartment allowing the introduction of the product and then the sealing of the package by bonding the unjoined edges; wherein at least one of the flexible sheets includes a polymer substrate, a vacuum-coated moisture-barrier layer thereover, and a metal foil of less than 20 microns over the moisture-barrier layer. 
     According to a still further aspect of the present invention, there is provided a flexible package for a product sensitive to moisture comprising: a front flexible sheet having moisture-barrier properties; and a back flexible sheet having moisture-barrier properties joined along its peripheral edges to the peripheral edges of the front flexible sheet except for one edge thereof to define a compartment allowing the introduction of the product and then the sealing of the package by bonding the one edge; wherein at least one of the flexible sheets is a multi-layer lamination including a first polymer substrate having a first vacuum-coated moisture-barrier layer, bonded to a second polymer substrate having a second vacuum-coated moisture-barrier layer. 
     According to yet another aspect of the present invention, there is provided a flexible package, comprising: a front flexible sheet; and a back flexible sheet joined along its peripheral edges to the peripheral edges of the front flexible sheet except for one edge thereof to define a compartment allowing the introduction of the product and then the sealing of the package by bonding the one edge; wherein the inner faces of the front flexible sheet and back flexible sheet are coated with an anti-static and/or electromagnetic shielding coating to dissipate electrical charges. 
     The invention also provides a flexible sheet comprising a first polymer substrate having a first vacuum-coated moisture-barrier layer, bonded to a second polymer substrate having a second vacuum-coated moisture-barrier layer. 
     According to a still further aspect, the invention also provides a method of making flexible packages, comprising: feeding two flexible polymer sheets, each having a moisture-barrier layer, through a longitudinally-extending path, with a surface of each sheet facing a surface of the other sheet; bonding the two sheets together along longitudinally-spaced transverse lines to define a plurality of individual compartments each having an open end; and cutting the bonded sheets along longitudinally-spaced transverse cut lines to define a plurality of individual packages each having a compartment and an open end for inserting a product into the respective compartment; wherein the surfaces of the two sheets facing each other are coated with an anti-static coating and/or electromagnetic shielding before the two sheets are bonded together along the transverse bond lines, to thereby impart anti-static properties, and/or to provide electromagnetic shielding, to each of the packages. 
     In one described embodiment, the anti-static and/or electromagnetic shielding coating is applied to each of the facing surfaces except the outer margins to be bonded together, and the bonding is effected by intermittently activating a heating element extending transversely across the two flexible sheets. 
     In another described embodiment, the anti-static coating and/or electromagnetic shielding is applied over the complete surfaces of each of the facing surfaces of the two sheets; an adhesive is applied over the anti-static coatings only along the outer margins to be bonded together; and the bonding is effected by intermittently activating a heating element extending transversely across the two flexible sheets in the longitudinally-extending path. 
     In yet a third described embodiment, the anti-static coating and/or electromagnetic shielding is applied over the complete surface of each of the facing surfaces of the two sheets; a heat-activatable adhesive is printed over the anti-static coating of at least one sheet, only along the outer margin to be bonded to the other sheet; and the bonding is effected by feeding the two sheets between heater rollers for activating the heat-activatable adhesive. 
     As will be described more particularly below, a flexible package constructed in accordance with the foregoing features of the invention can be produced with a high degree of moisture barrier properties, and with anti-static and/or electromagnetic shielding, properties if desired, can be manufactured in volume and at low cost, and can also accommodate different types of moisture indicators, desiccants, bar codes and/or RDIF&#39;s whenever desired to be introduced into the package, without changing the production apparatus or method. In addition, the invention permits the humidity indicators, desiccants, etc. to be applied to the product being packaged, rather than to the package itself, which provides a number of other important advantages. 
     Further features and advantages of the invention will be apparent from the description below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: 
         FIG. 1  pictorially illustrates one form of flexible moisture-barrier package (or pouch) constructed in accordance with the present invention,  FIG. 1  illustrating the product being partially inserted into the package; 
         FIG. 2  illustrates the main parts of the flexible moisture-barrier package of  FIG. 1 ; 
         FIG. 3  schematically illustrates an example of a process and apparatus for producing the flexible package of  FIG. 1 ; 
         FIG. 4  pictorially illustrates the multi-layer laminate containing an aluminum-foil used for the back flexible sheet and for the upper and lower sections of the front flexible sheet in the flexible package of  FIG. 1 ; 
         FIG. 5  pictorially illustrates the multi-layer, transparent-polymer structure in the optically-transparent section of the front flexible sheet of the  FIG. 1  package; 
         FIG. 6  pictorially illustrates another flexible package (or pouch) constructed in accordance with the present invention; 
         FIG. 7  illustrates a method which may be used in producing the package of  FIG. 6 ; 
         FIG. 8  illustrates yet another construction of flexible package in accordance with the present invention; 
         FIG. 9  schematically illustrates a method of making flexible packages in accordance with the present invention to include also anti-static or electromagnetic shielding properties; 
       and  FIG. 10  schematically illustrates another method of making flexible packages including anti-static properties or electromagnetic shielding properties. 
     
    
    
     It is to be understood that the foregoing drawings, and the description below, are provided primarily for purposes of facilitating understanding the conceptual aspects of the invention and possible embodiments thereof, including what is presently considered to be a preferred embodiment. In the interest of clarity and brevity, no attempt is made to provide more details than necessary to enable one skilled in the art, using routine skill and design, to understand and practice the described invention. It is to be further understood that the embodiments described are for purposes of example only, and that the invention is capable of being embodied in other forms and applications than described herein. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to  FIG. 1 , there is illustrated a flexible moisture-barrier package, generally designated  10 , constructed in accordance with the present invention for packaging a product  20  sensitive to moisture. As one example, product  20  to be packaged may be a roll containing electronic chips, which are sensitive to moisture. When product  20  is received within package  10  and the package completely sealed, the package provides a low moisture environment for the electronic chips carried by roll  20 , thereby not only prolonging the shelf life of the chips while still in the package, but also better assuring reliable operation of the chips when used in electronic circuitry. 
     Because of the sensitivity to moisture of the product  20  to be packaged, the product, or the interior of the package  10 , is provided with a humidity indicator  21  and also with a desiccant  22  for absorbing humidity within the package. Product  20  illustrated in  FIG. 1  is also shown as being provided with a bar code label  23  for identification purposes, and also with a radio-frequency identification device (RFID)  24  to permit identification, via radio-frequency, of the product within the package. 
     The flexible package  10  illustrated in  FIG. 1  is made of a back flexible sheet, generally designated  30 , having high moisture-barrier properties, and a front flexible sheet, generally designated  40 , also having high moisture-barrier properties. The two flexible sheets  30  and  40  are bonded together along their peripheral edges  11 ,  12  and  13 , except for the top edges which are left open to allow the introduction of the product  20  into the interior of the package. After the product  20  has been introduced into the package, the top edges of the two flexible sheets  20 ,  30  are bonded together to seal the product within the interior of the package. 
     The back flexible sheet  30  is made of an opaque sheet material having high moisture-barrier properties. A preferred construction for the back flexible sheet  30 , including a laminate containing aluminum foil, is described below with respect to  FIG. 4 . 
     The front flexible sheet  40  is made of three strips, namely upper and lower strips  40   a,    40   b,  joined to intermediate strip  40   c.  The upper and lower strips  40   a,    40   b  are also of an opaque material, whereas the intermediate strip  40   c  is of an optically-transparent material having moisture-barrier properties, to enable visually observing the product  20  within the package, and particularly the humidity indicator  21 , the bar-code label  23  and/or the RFID  24  carried by the product. The optically-opaque sections,  40   a,    40   b  of the front flexible sheet  40  are also preferably of the laminate containing aluminum-foil construction illustrated in  FIG. 4 , whereas the optically-transparent intermediate section  40   c  is preferably of a transparent-polymer laminate construction illustrated in  FIG. 5 . 
       FIG. 2  is an exploded view illustrating the back flexible sheet  30  and the three strips  40   a,    40   b,    40   c  of the front flexible sheet  40 .  FIG. 3  schematically illustrates a continuous production line for bonding the foregoing strips and sheets together to produce the package  10  in a stepwise mechanical manner. 
     Thus, as shown in  FIG. 3 , the front strips  40   a,    40   b  of the front flexible sheet  40 , are concurrently fed from rolls  51 ,  52  and  53 , respectively, with, and on opposite sides of, the multi-layer transparent polymer strips  40   c  of the front flexible sheet  40  from supply rolls  40   a,    40   b  and  40   c  respectively, along a longitudinal path indicated by arrow  54 . The multi-layer aluminum-foil laminate sheet defining the back flexible sheet  30  is supplied from another roll  55  to underlie the three strips of the front flexible sheet  40 . A pair of heat-sealing bars  56  are located upstream of supply roll  55  on opposite sides of the central multi-layer transparent-polymer strips  40   c  to bond the strips  40   a,    40   b  to the opposite edges of the central strip  40   c.  The three-part front flexible sheet  40  is thus produced before it reaches supply roll  55  for the back flexible sheet  30 . 
     At a point downstream of supply roll  55  supplying the back flexible sheet  30 , another heat sealing bar  57  is provided to bond the front flexible sheet  40  to the back flexible sheet  30  along a longitudinal edge. Slightly further downstream of supply roll  55 , another heat-sealing bar  58  extends transversely of the two sheets and is intermittently activated to bond them together along longitudinally-spaced transverse bond lines. Slightly further downstream, a cutter blade  59  periodically cuts the bonded sheets along transverse cut lines, to produce the individual packages  10  having the three bonded edges  11 ,  12  and  13  with the fourth edge open to permit introduction of the products being packaged. 
       FIG. 4  illustrates an example of a multilayer laminate that contains an aluminum-foil layer construction which may be used for the back flexible sheet  30 , as well as for the two strips  40   a,    40   b  of the front flexible sheet  40 . As shown in  FIG. 4 , such a multi-layer laminate containing aluminum-foil includes an aluminum layer  31  laminated by an adhesive layer  32  to a polymer substrate  33 , with a vacuum-coated barrier layer  34  inbetween. Aluminum-foil  31  further carries, on its opposite surface, a sealing layer  35  bonded thereto by another adhesive layer  36 . Barrier layer  34  on one side of the aluminum-foil  30  is effective to enhance the moisture-barrier or gases of the aluminum foil, and thereby to reduce dramatically the penetration of moisture therethrough. 
     As one example, aluminum layer  31  may be aluminum-foil of less than 20 microns, preferably 6 microns, in thickness; the substrate  33  may be a polyester such as PET (polyethylene teraphtalate) or polypropylene; the vacuum-deposit barrier layer  34  may be a vacuum-coated metal or oxide, such as alumina silicon dioxide, aluminum oxide, indium/tin oxide, etc.; sealing layer  35  may be polyethylene or polypropylene; and the two adhesive layers  32 ,  36  may be a polyurethane solvent based adhesive. 
     As indicated earlier, the same multi-layer aluminum-foil construction may also be used for the two strips  40   a,    40   b  of the front flexible sheet  40 . 
       FIG. 5  illustrates an example of a multi-layer transparent-polymer construction which may be used for the optically-transparent strip  40   c  of the front flexible sheet  40 . The optically-transparent section  40   c  of the front flexible sheet  40  is a multi-layer lamination including a first transparent polymer substrate having a first vacuum-coated moisture-barrier layer, bonded to a second transparent polymer substrate having a second vacuum-coated moisture-barrier layer. In addition, a transparent sealing layer is applied on the opposite sides of the multi-layer lamination. 
     Thus, as shown in  FIG. 5 , the multi-layer transparent polymer lamination includes, in this order: a transparent sealing layer  41 , an adhesive layer  42 , a transparent polymer substrate  43 , a vacuum-coated transparent barrier layer  44 , another adhesive layer  45 , another transparent polymer substrate  46 , another vacuum-coated barrier layer  47 , a further adhesive layer  48 , and a transparent sealing layer  49 . 
     The two transparent sealing layers  41 ,  49  may be polyethylene or polypropylene; the two transparent polymer substrates  43 ,  46  may be a polyester resin, such as PET; the two transparent barrier layers  44 ,  47  may be a vacuum-coated metal or oxide, such silicon dioxide, aluminum oxide, indium/tin oxide, etc.; and the adhesive layers  42 ,  45  and  48 , may be a polyurethane adhesive. 
       FIG. 6  illustrates another construction of a flexible package in accordance with the present invention. The package illustrated in  FIG. 6 , therein generally designated  220 , is also constructed for receiving products, such as indicated at  210 , having a high sensitivity to moisture. Package  220  illustrated in  FIG. 6  thus also includes a back flexible sheet  230  bonded to a front flexible sheet  240 , but in this case both flexible sheets are of the multi-layer laminate that contains an aluminum-foil layer construction, corresponding to the construction of the back flexible sheet  30  in  FIG. 1 , as illustrated in  FIG. 4 . However, the transparent sections of the front flexible sheet  240  are provided by forming, in the front flexible sheet, a plurality of openings defining windows  241 ,  242 , of sufficient number, and appropriately located, to permit viewing the humidity indicator, the desiccant, the bar-code label, and/or the RFID unit, as desired to be included in the package for the respective product. Here, the two flexible sheets  230 ,  240  in the package of  FIG. 6  would be of the same multi-layer laminate that contains aluminum-foil layer construction as the back flexible sheet  30  in the package  10  of  FIGS. 1-5 ; and each of the window openings  241 ,  242  would be covered by a transparent polymer sheet of similar construction as the transparent strip  40   c  in the package illustrated in  FIGS. 1-5 . 
       FIG. 7  schematically illustrates apparatus for producing the packages  220  illustrated in  FIG. 6  on a continuous basis. Thus, as seen in  FIG. 7 , the front flexible sheet  230  is supplied from a supply roll  251 . It is fed past a punching station  252  which punches-out the windows  241 ,  242 ; and then passes through a patching station  253  where patches of optically-transparent moisture-resistance sheets are applied to cover and seal the windows  241 ,  242 . The front flexible sheet  230  is then passed to a station containing a supply roll  254  which feeds the back flexible sheet  240 , then through a bonding station containing a heat-sealing bar  255  for continuously bonding the two sheets along one longitudinal edge; then through another bonding station containing another heat-sealing bar  256  which intermittently bonds the two sheets along longitudinally-spaced transverse bond lines to define a plurality of individual compartments each having an open end; and finally through a cutting station in which a cutter  257  cuts the sheets along longitudinally-spaced transverse lines, to produce the individual packages  210  each having a compartment and an open end for inserting a product into the respective compartment. 
       FIG. 8  illustrates a further flexible package, therein generally designated  310 , constructed in accordance with the present invention for packaging products  320  sensitive to moisture. In the package construction of  FIG. 8 , the back flexible sheet  330  is of the aluminum-foil laminate construction described above with the respect to the back flexible sheet  30  in  FIGS. 1 and 4 . However, the front flexible sheet  340  is completely of an optically-transparent moisture-resistant sheet. It is of the same multi-layer transparent-polymer sheet material as strip  40   c  in package  10  illustrated in  FIG. 1 , and more particularly described with respect to  FIG. 5 . Thus, the front flexible sheet  340  in package  310 , although completely transparent for its entire surface, would also provide a high degree of moisture resistance as described above with respect to  FIGS. 1 and 5 . 
     It is also highly desirable to provide packages with anti-static properties, in order to prevent the build-up of static charges, and/or to provide electromagnetic shielding.  FIGS. 9 and 10  illustrate two methods of producing packages in accordance with the present invention and having such anti-static properties. 
     Anti-static and/or electromagnetic shielding properties may be provided in such a package by coating the inner surfaces of the two flexible sheets with an anti-static coating, such as a polyaniline, indium tin oxide nano-particles, Baytron® and alike. However, such anti-static coatings do not bond well to each other, and therefore the use of such coatings can present problems in bonding the two flexible sheets along their peripheral edges in order to produce the compartments for receiving the products to be packaged. 
       FIG. 9  schematically illustrates one construction of a package and a method for making such packages which overcomes this problem. 
     As illustrated in  FIG. 9 , a package (or pouch) forming apparatus, generally designated  400 , continuously produces flexible packages  410  from two flexible, moisture-barrier sheets  430 ,  440 . The two sheets  430 ,  440  may be of any of the multi-layer constructions described above with respect to sheets  30 ,  40  of  FIG. 1 , and as more particularly described in  FIGS. 4 and 5 , respectively, except that each of the sheets would be provided, on its inner face (i.e. the face confronting the other sheet) with an anti-static coatings  431 ,  441 , respectively, for example of a polyaniline. As shown in  FIG. 9 , the anti-static coating  431 ,  441 , cover only the central area of the respective sheet; that is, they do not cover the outer margins, shown at  432 ,  442 , which are to be bonded together to define the compartment for receiving the product to be packaged. 
     One way of producing the construction illustrated in  FIG. 9  is to print the anti-static coating on each of the two continuous sheets used for making the packages (e.g., as illustrated in  FIG. 7 ) to cover only the central areas  431 ,  441 , of each sheet, and not to cover the margins  432 ,  442 , to be bonded in order to produce the packages. Thus, by printing the anti-static coatings and/or electromagnetic shielding only in the central areas  431 ,  441 , of each sheet, this exposes the underlying sealing layer of each sheet (e.g. sealing layer  35  in the multi-layer laminate that contains aluminum foil layer sheet  30  and sealing layer  49  in the multi-layer transparent polymer sheet  40 ) in the outer margins  432 ,  442  for producing the bond lines in the respective packages. 
     Another way of producing the configuration illustrated in  FIG. 9  is to continuously coat the anti-static coating on the respective face of the continuous sheet, or to use a polymer with inherent anti-static properties in the inner side of a multilayer laminate that makes the pouch, and to print an adhesive border in the margins  432 ,  442 , for bonding the two sheets together. The adhesive printed in the margins  432 ,  442 , could be any conventional adhesive, such as those used in the  FIGS. 4 and 5  multi-layer constructions, and the apparatus could be that of  FIG. 7  utilizing an intermittently-activated heat-sealing bar  256  for bonding the two sheets along transverse lines to produce the compartments of the respective packages. 
       FIG. 10  illustrates another method and apparatus for producing flexible packages in accordance with the present invention having anti-static properties. The method illustrated in  FIG. 10  includes a conventional laminating apparatus, generally designated  500 , including heating rolls  501 ,  502 , and a transversely-extending cutter bar  503 , for producing the packages  510  from two continuous, flexible sheets  530 ,  540 . The two flexible sheets  530 ,  540  could also be of the same multi-layer constructions described above particularly with respect to  FIGS. 4 and 5 . 
     In this case, however, the anti-static and/or electromagnetic shielding coating would be continuously applied to the inner faces of both sheets, or a polymer having anti-static and/or electromagnetic shielding properties would be used for the inner face; and a heat-activatable adhesive would be applied to the outer margins of one sheet (or both sheets) serving as the bond lines for producing the compartments in the respective packages  510 . Thus, as shown in  FIG. 10 , both sheets  530 ,  540 , are continuously coated with the anti-static coating  531 ,  541 , respectively, and a frame of heat-activatable adhesive is printed on one of the sheets, as shown at  532  in  FIG. 10 . Accordingly, when the two sheets  530 ,  540 , are fed between the heating rollers  501 ,  502  of the apparatus  500 , the heating rollers will activate the adhesive in the outer margins  532  to bond the two sheets together along those margins. 
     An example of the heat-activated adhesive used in the method illustrated in  FIG. 10  is Adcoat 295G supplied by Rohm and Haas (US); and an example of the normal adhesive used in the other described embodiments is Adcoat 509R, also supplied by Rohm and Haas (US). An example of the roller heating apparatus illustrated in  FIG. 10  is GMP of South Korea; whereas an example of the package-making (or pouch-making) apparatus illustrated in the other drawings is that supplied by Totani of Japan or Waterline of Switzerland. 
     Examples of vacuum coated transparent polymers are Techbarier® of Mitsubishi plastics of Japan. 
     Examples of antistatic and/or electromagnetic shielding is polyaniline of Panipol, Finland, Baytron® of H.C Starck of Germany and Indium tin oxide nano-particles of Degussa, Germany. 
     While the invention has been described with respect to several preferred embodiments, it will be appreciated that these are set forth merely for purposes of example, and that many other variations, modifications and applications of the invention may be made.