Patent Publication Number: US-2010113239-A1

Title: Method for making a flexible reclosable package

Description:
The present invention relates to methods for making a flexible reclosable package. 
     A variety of food and non-food products are packaged using flexible packaging materials formed primarily of laminations of one or more of polymer films, metallized polymer films, paper, metal foil, and the like. There is a desire to be able to reclose a package after its initial opening to keep product that remains in the package fresh. US 2005/0276525 describes such a package and a method for making the package. Briefly the process requires two film structures to be adhered to each other and then each film structure is scored at a location in registration with a strip of adhesive. The present invention improves on the process described in that application. 
     SUMMARY 
     According to one embodiment of the present invention, the flexible package is formed in the following manner. One or more film layers are laminated to form an outer layer structure. A pressure-sensitive adhesive is pattern-applied onto one surface of the outer layer structure to form a strip having an outer perimeter and an inner perimeter. A permanent laminating adhesive is pattern-applied onto the one surface of the outer structure such that the permanent adhesive does not cover the strip of pressure-sensitive adhesive. An outer line of weakness (also referred to as a “score line”) is formed through the thickness or at least a part of the thickness of the outer structure. The outer structure may also be printed in a conventional manner. 
     An inner layer structure is formed by laminating one or more film layers. The inner layer structure and the outer layer structure are joined to form a laminate. Thereafter, an inner line of weakness (also referred to as a “score line”) is formed through the thickness or at least a part of the thickness of the inner structure. The inner score line penetrates through the thickness of the inner layer structure but not through the outer layer structure. The outer structure and inner structure in certain embodiments are coextensive with each other. The formed laminate can be advanced to a take up roll where it can be unwound in a filling and sealing process, the details of which are known and do not form part of the present invention. 
     Advantageously, the score line created in the inner layer structure may be registered with respect to one or more of the printing on the outer layer structure, the outer line of weakness on the outer layer structure, and/or the pattern of the pressure sensitive adhesive on the outer layer structure. In addition, the outer score line in the outer layer structure can be formed without risk of scoring the inner layer structure since the inner layer structure and the outer layer structure are not yet laminated to each other. In addition, the inner layer structure can be laminated to the outer layer structure at any location of the inner layer structure, which simplifies the lamination process. The score lines can be formed by laser scoring or by mechanical scoring or cutting such as by die cutting, kiss cutting, or the like. 
     The strip of pressure-sensitive adhesive is such that neither score line is located where there is permanent laminating adhesive between the outer and inner structures. The outer score line delineates the outer opening portion of the outer structure that is separable from the outer structure along the outer score line, and the inner score line delineates the inner opening portion of the inner structure that is affixed to the outer opening portion by the permanent adhesive and is separable from the inner structure along the inner score line. The pressure-sensitive adhesive can be applied such that there is a region that is free of the adhesive to form a thumb tab or grasping portion of the opening portion that can be readily grasped and pulled back to initiate opening. 
     It is within the scope of the invention to use only pressure-sensitive adhesive, with no permanent laminating adhesive. In this instance, the pressure-sensitive adhesive is used to join the outer layer structure to the inner layer structure over their entire surfaces. The adhesive(s) can be applied to the outer structure as noted, but alternatively can be applied to the inner structure. The adhesive(s) can be applied using any suitable equipment and technique, such as by a gravure roll or the like. 
     The inner layer structure of the laminate may include a sealant layer forming the inner surface of the laminate. The sealant layer can comprise a heat seal material such as polyethylene, polypropylene, ionomer resin such as SURLYN® or the like, or a cold seal material. The heat seal or cold seal layer can comprise either a film or a coating. The inner structure may also include a barrier layer to provide a barrier against the passage of moisture and/or oxygen. In some applications such as the packaging of moisture-sensitive products (e.g., products that tend to be degraded when exposed to the environment), it is important to provide a moisture barrier. The barrier layer can comprise any of various polymer-based barrier materials including barrier polymer films such as ethylene vinyl alcohol copolymer (EVOH), polyamide, and the like; metallized polyolefin films such as polyethylene, polypropylene, oriented polypropylene, and the like; AlOx-coated polymer films; SiOx-coated polymer films; metal foil such as aluminum foil; and others. Although the term “barrier layer” is used in connection with metallized films to refer to the entire metallized film, it will be recognized that it is the layer of metal that provides the barrier function. Likewise, it is the AlOx or SiOx coating that provides the barrier function in the ceramic-coated films, but the entire film nevertheless is referred to herein as a “barrier layer”. 
     The outer structure may include a layer of polyester such as polyethylene terephthalate, that may have a desirable crisp feel and can be readily printed. The polyester layer can be printed with inks to provide graphics and indicia. In some embodiments, the polyester layer is transparent and is reverse-printed on the surface that faces the inner structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic depiction of a method for making a flexible package according to the present invention. 
         FIG. 2  is a view of the outer layer structure before being laminated to the inner layer structure and after being scored but without any printing. 
         FIG. 3  is a perspective view of a package that can be formed according to the method of the present invention shown in a closed position. 
         FIG. 4  is a perspective view of a package that can be formed according to the method of the present invention shown in an open position. 
         FIG. 5  is a cross-sectional view of a portion of the package in a closed configuration. 
         FIG. 6  is a cross-sectional view of a portion of the package in an open configuration. 
         FIG. 7  is a diagrammatic depiction of a method for making a flexible package according to the present invention, which contains features that can be used in the process depicted in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The invention is described with reference to the drawings in which like elements are referred to by like numerals. The relationship and functioning of the various elements of this invention are better understood by the following description. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. The embodiments described below are by way of example only, and the invention is not limited to the embodiments illustrated in the drawings. 
     As an initial overview of the invention, a flexible package  10  is provided with a built-in opening and reclose function, e.g., a resealable flap  20 . The package  10  is formed from a laminate  30  that is constructed as a multi-layer structure by scoring a first structure  40  and then adhesively laminating the first structure  40  to a second structure  60 . The scoring operation performed on the first structure  40  results in penetration through the first structure  40  without concern of penetration through the second structure  60 , since the first structure  40  and second structure  60  are not yet joined. Once the laminate  30  is formed in this manner, the second structure  60  is scored in registration with the scoring on the first structure  40 , the adhesive patterns and/or the printing formed on the first structure  40 . The scoring operation performed on the second structure  60  results in penetration through the second structure  60 , but without complete penetration through the first structure  40 , and preferably without any substantial penetration, and more preferably without any penetration, into the first structure  40 . Each of the first  40  and second structures  60  may include one or more layers of flexible material(s). Permanent and pressure-sensitive adhesives are applied to one of the structures in predetermined patterns. 
     Turning now to  FIG. 1 , one embodiment of the manufacturing process of the present invention is depicted. A first structure  40  is formed by joining a first layer  42  with a second layer  46 . The first layer  42  may be advanced from a supply roll  44  and the second layer  46  may be advanced from a different supply roll  48 . Adhesive  50  may be applied to the first layer  42 , the second layer  46 , or both. Thereafter, the first layer  42  and the second layer  46  may be joined in a laminating station  52  to form the first structure  40 . 
     Alternatively, the first structure  40  may be supplied from a roll of preformed first structure laminate  200  (as best seen in  FIG. 7 ). In addition, while  FIG. 1  shows the first structure  40  being formed from two film layers, it is contemplated that the first structure  40  could be formed from more than two layers, e.g., from three or more layers. In addition, the formed first structure  40  could be rolled up on a spool  200  for later processing, as described below. 
     Various materials can be used for the layer(s) of the first structure  40 , including polymers such polyesters, polyolefins (including homopolymers and copolymers), polyamides, and others; paper; metal foil; and the like. Advantageously, when metal foil is used as an inner layer, it allows partial scoring through the outer layer while maintaining structural integrity for later operations such as scoring, batch rolling, transporting, batch unrolling, and the like. 
     The first structure  40  may then be advanced by suitable web driving and handling equipment (not shown) to an optional print station  80  comprising a printing apparatus, such as a rotogravure printer or the like, for printing graphics and/or indicia on the first structure by applying inks to a surface of the first structure  40 . In one embodiment of the invention, the first structure  40  includes an outer layer that is substantially transparent and may be reverse-printed in the print station so that the inks will be visible through the first structure  40 . The inks may be applied to the surface of the first structure  40  that is subsequently laminated to another structure, as described below; from the opposite side of the first structure, which will form an exterior of a package  10  constructed from the laminate  30 . 
     Prior to printing the first structure  40  at the print station  80 , the surface of the first structure  40  to be printed can be treated by a corona discharge or flame treatment apparatus  82  to render the surface more-receptive to the inks and/or to render the surface more-readily bondable to the pressure-sensitive adhesive that is subsequently pattern-applied to the surface as described below. 
     Following the optional corona/flame treatment and/or optional printing operation, the first structure  40  may be advanced to the next processing stage or it may be rolled up onto a spool  202  (as best seen in  FIG. 7 ) and stored for subsequent processing operations. 
     The first structure  40  either from the previous processing step or from roll  202  is advanced to a scoring station  120  where a first score line  122  is formed through the thickness of the first structure  40 . The first score line  122  is in registration with (i.e., coincides with) the printing of the graphics or indicia or other features. The first score line  122  extends substantially through the thickness of the first structure  40 . 
     The first scoring station  120  can comprise a laser. The use of lasers for scoring through flexible materials is generally known, for example as described in U.S. Pat. Nos. 3,909,582 and 5,229,180, the contents of which are incorporated herein by reference. The depth of the score line formed by the laser can be regulated by regulating the power output or beam intensity of the laser beam, the width or spot size of the laser beam, and the amount of time a given spot on the film surface is irradiated by the beam. These factors generally are selected based on the characteristics of the material being scored. Some materials are more readily scored by lasers than other materials, as known in the art. 
     As noted, the first score line  122  should be in registration with one or more features such as printing, indicia marks, the location of the outer perimeter of the pressure-sensitive adhesive strip  92  (and the outer perimeter of the thumb tab  100 , if present, where the scoring is conducted after application of the adhesives), or other features that can be used to accurately locate the score line. To accomplish this registration, the operation of the laser is controlled to be synchronized with the advancement of the first structure. A sensor disposed adjacent the first structure can be used to detect a feature on the first structure (such as printing) whose location in relation to the strip of pressure-sensitive adhesive  92  is known, and the sensor&#39;s output signal can be used by a suitable controller (not shown) for controlling the laser. Subsequent to the scoring, the first structure  40  may be rolled onto spool  204  for subsequent processing (as best seen in  FIG. 7 ). 
     After scoring, the first structure may be advanced (either from spool  204  or from the previous continuous scoring station) to a first adhesive application station  90  at which a pressure-sensitive adhesive  92  may be applied to the first structure  40  in a predetermined pattern that recurs at regular intervals along the lengthwise direction of the first structure  40 . The predetermined pattern may be in the form of a strip of various forms or shapes. As illustrated, one shape for the strip pattern may be generally U-shaped or smile shaped, for reasons that will become apparent. Other shapes for the pattern can be used. The pattern can include a region that is free of adhesive  100  and that will ultimately form a thumb tab or grasping portion of the first structure  40  as further described below. 
     The pressure-sensitive adhesive  92  can comprise various compositions. Pressure-sensitive adhesives form viscoelastic bonds that are aggressively and permanently tacky, adhere without the need of more than a finger or hand pressure, and require no activation by water, solvent or heat. Pressure-sensitive adhesives are often based on non-crosslinked rubber adhesives in a latex emulsion or solvent-borne form, or can comprise acrylic and methacrylate adhesives, styrene copolymers (SIS/SBS), and silicones. Acrylic adhesives are known for excellent environmental resistance and fast-setting time when compared with other resin systems. Acrylic pressure-sensitive adhesives often use an acrylate system. Natural rubber, synthetic rubber or elastomer sealants and adhesives can be based on a variety of systems such as silicone, polyurethane, chloroprene, butyl, polybutadiene, isoprene, or neoprene. When the packaging laminate of the invention is to be used for food packaging, the pressure-sensitive adhesive generally must be a food-grade composition. Various pressure-sensitive adhesives are approved by the U.S. Food and Drug Administration for use in direct food contact, as regulated by 21 CFR Part 175.300. Food-grade pressure-sensitive adhesives are preferred for use in the present invention. Additives (e.g., particulates or the like) can be added to the pressure-sensitive adhesive to reduce the tenacity of the bond to the second structure  60 , if necessary, so that the pressure-sensitive adhesive  92  readily detaches from the second structure  60  on opening (particularly on the very first opening). 
     The pattern of pressure-sensitive adhesive  92  is applied to the first structure  40  at regular intervals along the first structure  40 . The spacing or index distance d between the patterns can correspond to a dimension, such as a length, of packages  10  to be produced from the laminate  30 . 
     The adhesive application station  90  can comprise any suitable device capable of accurately applying the pressure-sensitive adhesive  92  to the first structure  40  in the desired pattern at regular intervals along the first structure  40 . For example, the adhesive application station  90  can comprise one or more gravure rolls that pick up the pressure-sensitive adhesive  92  from a reservoir on the outer surface of the roll such that the adhesive fills one or more recessed areas in the surface. A doctor blade may then be used to scrape off excess adhesive so that it remains essentially only in the recessed area(s). The first structure  40  may be contacted by the gravure roll with a backing roll that may be used to provide support on the opposite side of the first structure  40 . 
     After application of the pressure-sensitive adhesive  92 , the first structure  40  may be advanced to a dryer  96  such as an oven or the like, to dry the pressure-sensitive adhesive  92 . The first structure  40  may then advanced to a second adhesive application station  110  at which a permanent laminating adhesive  112  is applied to the first structure  40  in such a manner that a sufficiently large proportion of the surface is covered by the permanent adhesive  112  to permit the first structure  40  to be adhesively attached to a second structure  60  at a downstream laminating station  130 . Alternatively, the first structure  40  may be advanced to the second adhesive application station  110  before being advanced to the dryer  96 . Thereafter, the first structure  40 , which contains both the pressure-sensitive adhesive  92  and the permanent laminating adhesive  112 , is advanced to the dryer  116  to dry the adhesives. 
     The permanent adhesive  112  does not cover the pressure-sensitive adhesive  92 . Furthermore, when the pattern of pressure-sensitive adhesive  92  includes an adhesive-free region  100  to form a thumb tab or grasping portion as previously noted, the pattern of the permanent adhesive  112  also does not cover the adhesive-free region  100 . Thus, the permanent adhesive  112  should be applied by an apparatus capable of accurately applying the permanent adhesive  112  in a predetermined pattern, in registration with the pressure-sensitive adhesive  92  but not covering it or the adhesive-free region  100 , if present. A suitable adhesive application device can be a gravure roll of the type previously described. 
     The permanent adhesive  112  can comprise various compositions. Suitable examples include two-component polyurethane adhesive systems, such as Tycel 7900/7283 available from Henkel. 
     While  FIG. 1  depicts a certain order of processing of the first structure  40 , it is contemplated that the various processing steps can be varied according to manufacturing and processing desires. Thus, for example, it may be desirable to apply adhesives prior to scoring. 
     After the application of the adhesives and any optional drying, the first structure  40  is advanced to a laminating station  130  that can include a pair of rolls forming a nip therebetween. The first structure  40  is passed through the nip along with a second structure  60  that is separately advanced, and the first structure  40  is laminated to the second structure  60 . 
     As noted above, the second structure  60  is advanced separately from the first structure  40  to the laminating station  130 . The second structure  60  may be formed from one or more layers. The second structure  60  may be coextensive with the first structure  40 , i.e., the width of the second structure  60  may be substantially equal to the width of the first structure  40  and the longitudinal edges of the second structure  60  substantially coincide with the longitudinal edges of the first structure  40 . 
     The second structure  60  may be supplied as one or more layers as shown in  FIG. 7 . For example, the second structure  60  may include only one layer when a metallic layer is included with the first structure  40 . 
     As shown in  FIG. 1 , the second structure  60  may be formed from two layers. In this instance, the second structure  60  is formed by joining a first layer  62  with a second layer  66 . The first layer  62  may be advanced from a supply roll  64  and the second layer  66  may be advanced from a different supply roll  68 . Adhesive  70  may be applied to the first layer  62 , the second layer  66 , or both. Thereafter, the first layer  62  and the second layer  66  may be joined in a laminating station  72  to form the second structure  60 . Additionally, either or both of the first or second layers may be a multi-layer laminate from a previous lamination operation. 
     Alternatively, the second structure  60  may be supplied from a roll of preformed second structure laminate. In addition, while  FIG. 1  shows the second structure  60  being formed from two film layers, it is contemplated that the second structure  60  could be formed from more than two layers, e.g., from three or more layers. 
     After the laminate  30  is formed, the laminate  30  may be rolled up on roll  206  for storage and later processing as shown in  FIG. 7 . Alternatively, as shown in  FIG. 1 , the laminate is advanced to a second scoring station  140  at which a second score line  142  is formed through the thickness of the second structure  60 . The second score line  142  is in registration with (i.e., coincides with) the inner perimeter of the strip-shaped pattern of pressure-sensitive adhesive  92 . The second score line  142  extends substantially through the thickness of the second structure  60 , but preferably does not extend to any substantial extent into the first structure  40 , as illustrated in  FIG. 5 . 
     The second scoring station  140  can comprise a laser. The operation of the laser is synchronized with the advancement of the laminate  30 . A sensor can detect a feature, such as an eye mark or printing, on the laminate  30  whose location in relation to the pressure-sensitive adhesive strip  92  is known, and the sensor output can be used for regulating the laser operation so that the second score line  142  is in registration with the inner perimeter of the pressure-sensitive adhesive strip  92 . 
     As an alternative to the use of lasers for scoring the laminate, the score lines can be formed by mechanical scoring or cutting. For instance, the first scoring station  120  can comprise a kiss roll and backing roll that form a nip through which the first structure is passed. The kiss roll may include a rotary cutting die defining a cutting edge (not shown). The kiss roll acts in conjunction with the backing roll to cut partially through the thickness of the first structure  40  starting from the outer surface of the first structure, such that the first structure  40  is substantially scored through. The second scoring station  140  may likewise comprise a kiss roll and backing roll for scoring through the second structure  60 . The kiss roll acts in conjunction with the backing roll to cut partially through the thickness of the second structure  60  starting from the outer surface of the second structure  60 , such that the second structure  60  is substantially scored through while the first structure  40  is left intact. 
     Additionally, it is within the scope of the invention to laser-score one of the first structure or the second structure and to kiss cut or otherwise mechanically score the other. This can be advantageous, for example, when one of the structures making up the laminate  30  is readily scored by a laser but the other structure is not. For instance, when the first structure  40  is a polyester such as PET, it can readily be scored with a laser, but if a polyethylene heat seal layer is employed on the second structure  60 , laser scoring may not be the best choice because polyethylene does not score well with a laser. In this case, kiss cutting or other mechanical scoring can be used to score the second structure  60 . 
     After the scoring operation, the laminate  30  can be sent to a reel-up or take up roll  150  and wound into a roll for subsequent processing. Alternatively, it is possible for the reel-up operation to be omitted, such that the laminate  30  is directly advanced to a fill and seal station. 
     The laminate  30  can also be slit into a plurality of partial widths and wound into multiple rolls. In this latter instance, each partial width would have the recurring patterns of pressure-sensitive and permanent adhesives applied with suitably configured adhesive applicators to the full-width material, and would have the recurring score lines formed by suitably configured scoring devices acting on either the full-width laminate prior to slitting or acting on each partial-width portion after slitting. 
       FIG. 3  shows a flexible package  10  in a closed position made according to the process described above. The package  10  includes an outer portion that envelopes the package contents and is sealed to enclose the contents. The outer portion comprises a laminate  30  made by a method in accordance with the invention, such as the laminate previously described. The outer portion is manipulated and sealed along seal lines. 
     In the illustrated package, the score lines  122 ,  142  are provided to be on a front surface  16  of the package  10 . The area of the package  10  bounded by the score lines can constitute any fraction of the total front surface of the package, but advantageously the area is a majority of the total surface area of front surface  16 . 
     Based on the previous description of the laminate  30  and its formation process, it will be appreciated that the presence of the score lines has little or no impact on the barrier function of the package  10  because each score line  122 ,  142  extends only partially through the total thickness and the score lines are not aligned with each other. Additionally, the pressure-sensitive adhesive  92  fills the space between the score lines so that even if the score lines overlap somewhat in the thickness direction, there is still no open route between them. Furthermore, the score lines typically have a small width, on the order of a few thousandths of an inch. 
     Various materials can be used for the construction of the package  10 . As noted above, the first structure  40  that forms the outer surface of the package  10  may comprise a single layer of flexible material or several layers of various materials. One material is a polyester such as polyethylene terephthalate (PET). As noted, the PET layer can be reverse-printed if desired, although alternatively it can be printed on its exterior and covered by an over-lacquer (not shown). The second structure  60  forming the inner surface of the package  10  may comprise a barrier layer and a sealant layer. The sealant layer constitutes the innermost surface of and can comprise various sealant materials such as heat seals or cold seals. Heat seals generally are preferred because they provide stronger seals than cold seals typically are capable of achieving. Any suitable heat seal material can be employed, such as polyethylene, polypropylene, ionomer resins such as SURLYN®, or others. 
     The barrier layer can comprise any of various barrier materials including barrier polymer films such as: ethylene vinyl alcohol copolymer (EVOH), polyamide, and the like; metallized polyolefin films such as polyethylene, polypropylene, oriented polypropylene, and the like; AlOx-coated polymer films; SiOx-coated polymer films; metal foil; and others. The barrier layer and sealant layer can be joined in various ways, including adhesive lamination, extrusion lamination, or coextrusion. 
     The laminate  30  may also include a metallization layer or a metal foil layer between the first structure  40  and the second structure  60 , for example by providing a metallization layer on the surface that faces the first structure  40 . This is beneficial in enhancing the barrier performance of the laminate  30 . The metallization layer or metal foil layer can also be helpful when a laser is used for scoring the second structure  60 . In particular, when the sealant layer comprises polyethylene, which is not as readily scored by laser as some other materials such as polyester, it can be difficult to employ a sufficiently high laser energy to score through the polyethylene sealant layer without scoring through the laminate  30  more deeply than desired. In particular, it is undesirable to score the entire thickness of the laminate. The metallization layer or metal foil layer can be helpful in “tuning” the laser to penetrate only up to the metallization layer or foil layer. 
     The function of the resealable flap provided by the pattern-applied adhesives and the score lines will now be described. With reference to  FIGS. 3 and 4 , the package  10  is shown in a closed condition ( FIG. 3 ), for example as initially filled and sealed in a packaging plant. The package  10  has edges  14 ,  16 ,  18 , that are sealed to each other with a top edge  12  that may be formed by folding the laminate  30  on itself. On the front surface  22 , the first or outer structure is adhesively joined to the second or inner structure via the permanent adhesive. The outer score line  122  bounds an outer opening portion of the outer structure. In this embodiment, the outer opening portion has a generally U-shaped or smile shaped perimeter having three sides defined by the score line  122 , and is attached to the remainder of the outer wrapper along a fourth side (i.e., an imaginary line extending between the free ends of the two legs of the U-shaped score line). The inner score line  142  is also generally U-shaped or smile shaped with its portions parallel to adjacent portions of the outer score line  122 , but is spaced inwardly of the outer score line  122  so as to define an inner opening portion of smaller area than the outer opening portion. Accordingly, there is a marginal region of the outer opening portion that extends beyond the edge of the inner opening portion. The pressure-sensitive adhesive  92  is disposed between this marginal region and an underlying surface of the inner structure. The outer opening portion and inner opening portion are permanently joined by the permanent adhesive. 
     Consequently, when the outer opening portion is detached from the outer wrapper along the outer score line  122  and is peeled back as depicted in  FIG. 4 , the inner opening portion remains affixed to the outer opening portion and comes with it, thereby creating an opening in the front surface  22  as defined by the inner score line  142 . The outer and inner opening portions essentially form a flap  20  that remains attached along a hinge line defined between the free ends of the two legs of the U-shaped score lines. 
     The outer structure preferably has a greater affinity for bonding with the pressure-sensitive adhesive  92  than does the surface of the inner structure, and hence the pressure-sensitive adhesive  92  is detached from the surface and remains attached to the marginal region of the outer opening portion. The package  10  is reclosable by re-attaching the pressure-sensitive adhesive  92  to the surface of the inner structure to restore the package  10  to the condition shown in  FIG. 3 . 
     The greater bonding affinity of the outer structure can be achieved in various ways. When the outer structure comprises a layer of PET and the layer of the inner structure to which the pressure-sensitive adhesive  92  is attached comprises a polyolefin such as polypropylene, oriented polypropylene, or metallized oriented polypropylene, the PET will naturally have a greater affinity for bonding to the adhesive than will the polyolefin layer. Additionally or alternatively, the surface of the outer structure can be treated, as previously noted, by corona discharge or flame treatment, to increase the surface energy and enhance the bonding affinity. It is also possible, as already noted, to control the bond strength of the pressure-sensitive adhesive to the layer by including an additive in the adhesive to reduce the bond strength, if desired. 
     Although it is preferred to have the pressure-sensitive adhesive  92  be applied to the outer structure and to remain on the outer structure upon opening, it is also within the scope of the invention to apply the pressure-sensitive adhesive to the inner structure and to remain on the inner structure upon opening. This is less preferred, however, because of the greater tendency for crumbs or the like from the contained products to become adhered to the pressure-sensitive adhesive and thereby reduce its adhesiveness with repeated openings and reclosings. It is believed that this tendency is reduced when the pressure-sensitive adhesive remains with the outer structure, since it is out of the way of the package opening when products are being removed. 
     It will be appreciated from the above description that laminates made in accordance with the invention inherently provide a tamper-evidence function for a package because after opening it is very difficult or impossible to replace the opening portions in such a way as to achieve a completely smooth, flush condition with the surrounding portion of the laminate. It tends to be readily ascertainable that the package has been opened. When printing is included on the laminate, it is even more noticeable when the package has been opened because it is difficult to achieve perfect registration of the printed matter across the score line when reclosing the package. 
     Additionally, other tamper-evidence features can be incorporated into the packaging structure. For example, when the outer structure is reverse-printed with ink, an area on the marginal region of the outer opening portion can first be treated (such as by applying a release coating or the like) to reduce the adherence of the ink so that when the package is first opened, the ink on the area of the marginal region detaches from the marginal region of the outer opening portion and remains with the pressure-sensitive adhesive on the inner structure adjacent the package opening. The release coating can be applied in a pattern (e.g., spelling out a word such as “Opened” or the like). Other types of tamper-evidence features can be included. 
     Referring back to  FIG. 4 , the package  10  of the present invention is shown with the resealable flap  20  in an open position to expose the contents of the package  10 . The package  10  includes opposed major surfaces only one of which is shown, an opposed top and bottom, and opposed ends or sides. One of the major surfaces is scored to define a resealable flap  20  that can be opened to expose the contents stored within the package. 
     The package of the present invention is shown as containing sticks (or tabs) of gum  2 . It is to be understood, however, that the use of the package  10  is not limited to gum, confections, or even consumable products. Therefore, as is known, gum sticks  2  may be elongate rectangular shaped members that are individually wrapped with a wrapper  4  in a conventional fashion. The wrapper  4  may be a rectangular shaped member typically made of paper or foil. Typically, the longitudinal edges of the wrapper  4  are overlapped and the ends of are turned over against the stick to enclose the stick completely. 
       FIG. 1  variously shows unwrapped gum sticks  2  and gum sticks contained in wrappers  4 , where the gum sticks were individually wrapped prior to being placed in the package. The wrapper may be a single sheet or may include plural sheets or layers. It is noted that the gum sticks can be placed in an array directly into the package, without being individually wrapped. 
     While  FIG. 1  shows the gum sticks aligned in a single row, it is to be understood that the gum sticks (wrapped or not) can be placed in a face-to-face manner, i.e., in two or more columns to form the array. When two or more columns are provided, each row may be encircled partially or completely by a wrapper to better contain the individual gum sticks. The array of gum sticks is placed in the package and are retained and enclosed. A portion of the inside of the package may contain an adhesive to releasably secure the gum sticks until the consumer removes them from the package. 
     Although it is not depicted, it is contemplated that one or more gum sticks may be contained within a flexible package and that one or more flexible packages may be provided in the package  10 . For example, it is currently known to provide a flexible package for containing five sticks of gum. These flexible packages (or portions of them such as a bottom portion) may be stored in the package  10 . 
     It should be noted that the terms “line of weakness” and “score line” as used herein refer either to a complete cutting through of one or more layers of the laminate or to a weakening of such layer(s) allowing the layer(s) to be severed along the score line. 
     The foregoing detailed description has described only a few of the many forms that this invention can take. For this reason, this detailed description is intended by way of illustration, and not by way of limitation. It is only the following claims, including all equivalents, which are intended to define the scope of this invention.