Abstract:
A child-resistant multi-step tear-access blister package having at least one product well containing a product. The product is accessed by tearing the blister package from a peripheral edge toward the product well. A step in addition to tearing is required to access the product, thereby elevating the cognitive skill necessary to access the product above those of a typical small child. In the disclosed exemplary embodiment, the additional step involves weakening a tear-resistant channel blocking a tear path from the peripheral edge of the package to the product well. More particularly, initial tearing of the package toward the product well is interfered with by the presence of the tear-resistant channel interrupting the tear path. The tear-resistant channel may be bent or snapped to permit tearing therethrough and to permit continued tearing of the blister package toward the product well to access the product.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a blister package that is difficult for a small child to open, yet readily opened by an adult, including senior and physically disabled adults. 
       BACKGROUND OF THE INVENTION 
       [0002]    A wide variety of blister packages for packaging a variety of consumer products are available in the art. These blister packages typically are formed of a transparent layer (the “blister”) coupled (preferably sealed or otherwise bonded) to a backing layer. The blister has a well or cavity or other type of deformation formed therein such that upon coupling of the blister to the backing layer a compartment or pouch is formed for holding or containing a desired product. The product well(s) may be accessed by stripping the backing layer from the package to expose the well and the product therein, or to expose a rupturable/push-through backing layer below the well through which the product may be pushed upon exerting pressure on the blister and the article (a “peel-and-push” blister package). Alternatively, the well(s) may be accessed by tearing the edge of the package toward such well(s) (a “tear-access” blister package). A starting notch or slit may be provided to facilitate tearing. 
         [0003]    One common use of blister packages is for packaging solid-dose medications or pharmaceuticals (e.g., tablets, capsules, caplets, and the like; hereinafter “medications” for the sake of convenience and with no intent to limit) or consumer products. Such packaging typically is desirable for carrying individual/unit doses of medication, and may afford a greater level of portability than other types of packaging (e.g., bottles). Like typical blister packages, blister packages for medications generally permit moderately easy viewing of the contents therein. Such easy viewing may tempt a small child to try to access the product. The Consumer Product Safety Commission has established rules governing which products require special packaging and standards for such special packaging in the Poison Prevention Packaging Act of 1970, outlined in the Code of Federal Regulations, Title 16, Part 1700. “Special packaging,” commonly referenced as child-resistant or CR packaging, is defined in 16 C.F.R. § 1700.1 (b)(4) as “packaging that is designed or constructed to be significantly difficult for children under 5 years of age to open or obtain a toxic or harmful amount of substance contained therein within a reasonable time and not difficult for normal adults to use properly, but does not mean packaging which all such children cannot open or obtain a toxic or harmful amount within a reasonable time.” Products requiring special packaging include all prescription medications and over-the-counter medications, and a variety of other substances that are harmful if handled, used, or ingested. Child resistant blister packages are also desirable for packaging any other type of article that is unsafe for a child, such as medical instruments, sharp objects, or addictive substances (e.g., caffeine, nicotine, etc.). 
         [0004]    A variety of manners of forming a child-resistant blister package are known in the art. For instance, a peel-and-push type blister package generally requires sufficient cognitive skills to render the package child-resistant. Tear-access type blister packages may be formed of a tear-resistant material that is nearly impossible to tear unless the material is weakened (such as by perforations) and a minimum amount of force, generally greater than within the capacity of a child, is used. Child-resistant blister packages must, however, take into account the needs of the adults who are to access its contents. In particular, the child-resistant blister package should be designed to permit senior and physically disabled adults to open the package readily. If the tear resistance of a child-resistant tear-access blister package is reduced for ready opening by a senior or physically disabled adult, then there is a risk that a child may open such package as well. 
         [0005]    Additional features (e.g., requiring folding, tearing, or stripping to gain access to the content of the product well) may be required to add a further step beyond the cognitive skills of small children. Thus, a high tear resistance may not be necessary for a tear-access blister package to still qualify as child resistant. For instance, a tear-initiating notch (generally required in tear-resistant blister packages for initiating a tear) may be inaccessible unless the blister card is folded over, such as disclosed in U.S. Pat. Nos. 3,809,220 to Arcudi and 5,511,665 to Dressel et al. Alternatively, a portion of the blister card may have to be removed first in order to permit tearing of the package to access the contents of the blister, as disclosed in U.S. Pat. No. 6,422,391 to Swartz. The requirement of tearing at a particular location on the blister package also elevates the cognitive skills required to open the package, such as requiring initial tearing through a peripheral tearing blister, as disclosed in U.S. Pat. No. 6,036,016 to Arnold. Another added step elevating the cognitive skills required to open the blister package beyond those of a typical child may be to require manipulation of the medication in the blister before rupturing the blister package to access the medication, such as disclosed in U.S. Pat. Nos. 4,371,080 to Haines and 5,529,188 to Coggswell. 
         [0006]    There remains a continuing desire in the industry to improve the child-resistant features of tear-access blister packages to improve consumer friendliness and ease of opening for adults, including senior and physically disabled adults. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a blister package that is particularly suitable for limited access or child-resistant applications. Preferably, the force required to open a child-resistant tear-access blister package formed in accordance with principles of the present invention is not so great that a senior or physically disabled adult would have difficulty opening such package. Thus, in accordance with the principles of the present invention, the child-resistant features of the blister package of the present invention rely on requiring a level of cognitive skills to open the package beyond those of a child (at least of the age specified in Title 16 of the C.F.R., Part 1700) yet well within those of senior or physically disabled adults. 
         [0008]    A tear-access blister package formed in accordance with the principles of the present invention requires multiple steps in order to access the product contained within the blister well, yet preferably does not require a high degree of force or strength to be opened. In a preferred embodiment, the tear-access blister package is relatively easy to tear open, but the tearing action is interrupted so that at least one additional step must be performed (preferably other than tearing) in order to access the contents of the package. For instance, in the embodiment described herein, a tear-resistant blister channel is provided in the tear path (from the peripheral edge of the blister package where the tear is initiated to the product well) so that the tear-resistant blister channel must be weakened (such as by snapping or simple bending) in order to continue tearing the blister package toward the product well to access the product. Such additional step achieves a greater level of child-resistancy than achievable by merely increasing the force required to tear the package. Moreover, the interruption of tearing of the package toward the product well results in what essentially is a three step process for opening the package—(1) initial tearing, (2) weakening the tear-resistant blister channel, and then (3) continuing to tear again. 
         [0009]    These and other features and advantages of the present invention will be readily apparent from the following detailed description of the invention, the scope of the invention being set out in the appended claims. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The detailed description will be better understood in conjunction with the accompanying drawings, wherein like reference characters represent like elements, as follows: 
           [0011]      FIG. 1  is a perspective view of a blister package formed in accordance with the principles of the present invention; 
           [0012]      FIG. 2  is a side elevational view of the blister package of  FIG. 1 ; 
           [0013]      FIG. 3  is a plan view of the blister package of  FIG. 1 ; 
           [0014]      FIG. 4  is a perspective view of the blister package of  FIG. 1 , with a tear being initiated; 
           [0015]      FIG. 5  is a perspective view similar to that of  FIG. 4 , but with tearing interrupted by an optional keyhole; 
           [0016]      FIG. 6  is a perspective view similar to that of  FIG. 5 , but with tearing interrupted by a tear-resistant blister channel which must be further manipulated; and 
           [0017]      FIG. 7  is a perspective view similar to that of  FIGS. 4-6 , showing a tear that has propagated through the tear-resistant blister channel; and 
           [0018]      FIG. 8  is a perspective view similar to that of  FIGS. 4-7 , showing a tear that has propagated to the product well to grant access to the product within the product well. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    The principles of the present invention may be applied to blister packages for packaging any type of product that is not to be readily accessed by a child. Exemplary blister package  100 , formed in accordance with principles of the present invention and illustrated in  FIGS. 1-6 , is made up of blister  102 , in which at least one product well  104  is formed, and blister backing  106 , as may be seen with particular reference to  FIG. 2 . Blister  102  and blister backing  106  preferably are coupled together to retain a product within product well  104 . For example, blister  102  and blister backing  106  may be sealed together, such as by conduction or any sealing method known in the art, to prevent ready access to the product held therein. Depending on the product within product well  104 , it may be desirable to form a hermetic seal about product well  104 . 
         [0020]    In the exemplary embodiments of  FIGS. 1-8 , product well  104  is shaped for holding or containing a medication, drugs, or pharmaceuticals (e.g., tablets, capsules, caplets, and the like; hereinafter “medications” for the sake of convenience, and without any intent to limit). However, it will be appreciated that product well  104  may be shaped to contain items of different sizes and shapes other than those for typical medications. Additional wells or cavities  110 ,  112 ,  114  may be formed, such as to provide brand information and/or a logo, such as illustrated by well  110 . Alternatively, or additionally, at least three additional wells of equal height (and preferably the same height as product well  104 ) may be provided to facilitate stacking of blister packages  100  on top of each other for loading into a carton in an efficient manner. 
         [0021]    Blister  102  may be formed from a rupture-resistant, semi-rigid material. Any conventional thermoformed material used in blister packaging, such as plastic, or cold-formable materials, such as plastics or foils or foil-plastic lamination, may be used. Preferred materials include PVDC, a combination of PVC/PE/PVDC, pharmaceutical grade PVC, or another thermoplastic material, such as plastic, polypropylene, polyethylene, styrene, cold-formed foil, or other suitable materials for packaging. The material may be a single ply or multiple plies or laminations. If desired, such material may be selected to retain a desired shape and to be crush resistant so that a friable product within product well  104  is retained therein without being damaged. If viewing of the product within product well  104  is desirable, then a plastic, rather than a foil, is used. Of course, compatibility of the blister material with the product to be contained within product well  104  (particularly when such product is a medication) is an important factor in selection of a material for blister  102 . Barrier properties (e.g., in terms of moisture and oxygen protection) may also be an important consideration. For instance, a cold-formed foil is generally necessary for stability of more hydroscopic medications, such as chewable medications. Protection from UV light may also be an important consideration for certain products, requiring translucent or opaque material to be used for blister  102 . Any other characteristics that would contribute to stability of the product may affect the selection of material for forming blister  102 . 
         [0022]    In order to prevent the product held within product well  104  from being pushed through blister backing  106  (and thus rendering the blister package  100  not child-resistant), blister backing  106  is preferably formed from a rupture and puncture resistant material, such as a tear-resistant lamination. Preferably, the material of blister backing  106  is selected to be compatible with the material of blister  102 , such as for heat sealability. Additionally, as with blister  102 , compatibility of the blister material with the product to be contained within product well  104 , barrier properties (as described above), UV protection, and other characteristics (such as, but not limited to, those that would contribute to stability of the product) may be important considerations in selecting the material of blister backing  106 . Exemplary materials that may be used for blister backing  106  include, without limitation, PET, a PET foil lamination, or some other lamination of oriented polypropylene. If desired, the material of blister backing  106  may be substantially rigid to retain the overall stiffness of blister package  100 . However, the rigidity of blister  102 , or the rigidity resulting upon coupling of blister  102  with blister backing  106  may be sufficient such that relative rigidity of blister backing  106  is unnecessary. 
         [0023]    Because blister package  100  is preferably a tear-access blister package, tearability of the materials used to form blister package  100  is generally a factor in selecting the materials. Generally, if blister package  100  is to have a degree of child-resistance, the material of blister  102  and/or the material of blister backing  106  is selected to be at least somewhat tear-resistant. The degree of tear resistancy is based on the level of child-resistancy desired or necessary for the blister package. The tear resistance of the blister material or the tear-resistance resulting from coupling the blister and the blister backing may be sufficient such that the blister backing material need not be tear resistant. Likewise, the tear resistance of the blister backing material or the tear-resistance resulting from coupling the blister backing and the blister may be sufficient such that the blister material need not be tear resistant. The sealing of blister  102  and blister backing  106  may together further strengthen the overall tear-resistance of blister package  100 . 
         [0024]    Generally, the material of blister  102  and/or the material of blister backing  106  is selected to be tearable only when weakened, such as by cuts, nicks, scores, perforations, or other lines of weakening (hereinafter “weakening(s)” will be used to refer to all such weakenings for the sake of convenience only, and with no intent to limit). The particular type of weakening may be selected based on the level of child-resistancy required, or other various factors (including, but not limited to, tamper-evidency desired, or machining or other manufacturing constraints). For instance, perforations typically provide a cleaner break than do scoring, and are typically easier to form (regulation of the depth of a score line in a relatively thin material generally requires a higher degree of control than required to completely cut through a material such as to create perforations). The land areas between the perforations may be varied to alter the ease of tearing therethrough. In addition, the material of blister  102  and/or the material of blister backing  106  may be oriented to facilitate tearing in a particular direction. It will be appreciated that the materials of blister  102  and blister backing  106  may be selected so that they may be cut through with scissors. 
         [0025]    Blister package  100  as a whole preferably is resistant to being torn or opened at places other than along weakenings. Thus, an initial weakening, such as a tear notch  120 , may be provided at least one location along the peripheral edge of blister package  100 , as illustrated in  FIGS. 3 and 4 . In the embodiment illustrated in  FIGS. 1-8 , blister package  100  is oblong with product well  104  at one end (along the major axis of the package) and initial tear notch  120  at the other end, such that use of initial tear notch  120  to access the product well  104  at the opposite end of blister package  100  is not necessarily intuitive for a young child. However, it will be appreciated that other configurations are well within the scope of the present invention. Initial tear notch  120  may lead to an initial weakening  122  that further facilitates tearing of blister package  100  to access the contents of product well  104 . Although initial tear notch  120  is illustrated in  FIG. 3  as a notch, initial tear notch  120  need not specifically be shaped as a notch, and may be any other modification to blister package  100  that facilitates tearing therethrough. For instance, a simple cut through the material of blister package  100  may be provided. Alternatively, initial weakening  122  may be provided spaced a short enough distance from the peripheral edge of blister package  100  to facilitate initial tearing specifically near such weakening, yet creating a land area between initial weakening  122  and the peripheral edge of blister package  100  small enough as to not be readily apparent to a child. Such design would result in a package that is moderately difficult to start tearing, but once tearing has been initiated and the weakening reached, is relatively easy to continue tearing. Preferably, sufficient blister packaging material (i.e., the combined layer of blister  102  and blister backing  106 ) is provided to grasp the packaging adequately to initiate tearing. As in the embodiment of  FIGS. 1-8 , initial tear notch  120  may be offset from the central axis of blister package  100  to facilitate grasping of a sufficient surface area of blister package  100  with one hand while grasping the smaller remaining surface area of blister package  100  to tear blister package  100 . 
         [0026]    In accordance with the principles of the present invention, simple tearing of blister package  100  is inhibited to result in a child-resistant blister package that is nonetheless readily opened by senior and physically disabled adults. More particularly, an action in addition to simple tearing must be performed to gain access to the content of product well  104 . In the embodiments of  FIGS. 1-8 , the presence of a tear-resistant channel  124  in the tear path from the edge of blister package  100  toward product well  104  interferes with further propagation of the initial tear through blister package  100 . If desired, initial weakening  122  in blister package  100  may optionally end (in a direction away from the peripheral edge of blister package  100  and toward product well  104 ) at a keyhole  125 , which further inhibits further tearing along initial weakening  122  upon reaching tear-resistant channel  124 , as illustrated by  FIG. 5 . The spacing of keyhole  125  from tear-resistant channel  124  is determined based on the desired tear-resistant affect, and is influenced by such factors as the tear-resistance of the material(s) of blister package  100 . It is believed that the configuration of tear-resistant channel  124  interferes with the propagation of the initial tear because the direction of tearing (initially within the major plane of blister package  100 ) is altered, requiring deflection of the direction of tearing force applied to blister package  100 . Such interference generally results in enough deterrence that a small child loses interest in opening blister package  100 , thereby adding a level of child-resistance to blister package  100 . Tear-resistant channel  124  may also serve an additional function of stiffening blister package  100  so it does not warp or otherwise bend or deform. If desired, tear-resistant channel  124  may extend around the entire periphery of blister package  100 , encircling product well  104 , as illustrated in the exemplary embodiment of  FIGS. 1-8 , thereby adding a further level of child-resistance. 
         [0027]    Because tear-resistant channel  124  does not readily tear, an action in addition to tearing must be performed in order to continue tearing blister package  100  to access the contents of product well  104 , as illustrated conceptually by  FIG. 6 . Generally, manipulation of tear-resistant channel  124  to weaken tear-resistant channel  124  is required. For instance, if the material of blister  102  is relatively frangible, then breaking or snapping of tear-resistant channel  124  may be necessary in order to continue tearing blister package  100  toward product well  104 . Alternatively, simple bending of tear-resistant channel  124  may suffice to weaken tear-resistant channel  124  sufficiently to permit tearing therethrough. As will be appreciated, various characteristics of the material of tear-resistant channel  124  will affect if it breaks or bends. The size and shape of tear-resistant channel  124  may be modified to enhance or to affect the interference it creates in opening blister package  100  and its consequent affect on the child-resistancy of blister package  100 . If desired, tear-resistant channel  124  may be weakened, such as by a nick  127  (see  FIGS. 3-6 ). 
         [0028]    Once tear-resistant channel  124  has been sufficiently weakened or otherwise manipulated to permit tearing therethrough, tearing may proceed toward product well  104 , as illustrated conceptually by  FIG. 7 . If desired (generally depending on the desired child resistancy of blister package  100  and the materials of blister- 102  and blister backing  106 ) an additional weakening  126  may be provided to facilitate propagation of the tear from tear-resistant channel  124  toward product well  104 . In view of typical stability requirements of the product additional weakening  126  preferably ends a short distance from product well  104 , as illustrated in  FIG. 7 , to maintain the integrity of the seal of product well  104 . The industry standard typically requires a cut in the blister package to be no more than approximately 2-4 mm from the seal of the product well. Tearing into product well  104  once the end of additional weakening  126  has been reached is relatively simply achieved to reach the contents of product well  104 , as illustrated in  FIG. 8 . 
         [0029]    The formation of blister package  100  of the present invention may be achieved in accordance with any desired method of manufacture achieving the child-resistant features of the present invention. For instance, blister  102  and blister backing  106  may be supplied as separate rolls of material to a blister-package-forming machine (machines such as those sold by Uhlmann Packaging Systems, Inc. of Towaco, N.J., or Klöckner Pentaplast, of Gordonsville, Va., may be used). The blister material may be unrolled and passed through a forming section at which blister sections such as product well  104 , tear-resistant channel  124 , and additional wells  110 ,  112 ,  114 , may be formed, such as by vacuum pressure, thermoforming, or a mechanical deformation process. For instance, the blister material may be stretched into a cavity with a vacuum applied thereto to form blister sections. Alternatively, the blister material may be exposed to heating elements for a pre-determined time, and then trapped in a forming station where the blister material is subjected to both vacuum and pressure. During this process, the blister material may also be mechanically assisted into the blister cavity or mold via a matched metal plug to form any or all of the blister sections. The blister sections can alternatively be formed by using cold-formed foil and cold-form packaging processes. 
         [0030]    Once blister sections are formed in blister  102 , a product is placed in product well  104 . Backing layer material may then be fed from a roll and sealed to blister  102  and the bottom of the filled product well  104  to seal the product within product well  104  and blister package  100 . Blister  102  and the blister backing  106  may be joined together by any sealing method known in the art that adequately seals a product within product well  104 . For instance, if the product has a low stability or shelf-life such that an air-tight seal is necessary, then the materials of blister  102  and blister backing  106  and the sealing method are selected to achieve an air-tight seal around product well  104 . Exemplary sealing methods include heat sealing, adhesive seals (such as with heat-activated or solvent adhesive), RF or sonic seals, or any other suitable means. Typically, conductive sealing through heated plates (e.g., a thermoforming operation) is used. The materials of blister  102  and the blister backing  106  may be pre-treated to facilitate sealing of such materials together. For instance, a coating may be applied to either or both materials to permit heat sealing (generally necessary with foils that do not readily heat seal to PVC or PVDC). 
         [0031]    Weakenings, such as described above, may be formed at any desired stage of forming blister package  100 . For ease of manufacturing, blister package  100  is passed through equipment designed to form the desired type of weakenings once product wells  104  have been filled and blister  102  and backing layer  106  are sealed together. Once blister package  100  has been formed with its desired child-resistant features, it may be passed through die-cutting equipment for separation from the rolls of blister and blister backing materials. If a nick is provided on the tear-resistant channel (depending on the level of child-resistance required), it may be formed in the thermoforming mold or at the section at which the other weakenings are created. 
         [0032]    As should be appreciated from the foregoing, a blister package formed in accordance with the principles of the present invention is simple in construction, can be made economically and relatively simply, provides a protective environment for products, and can be readily opened without the use of utensils, such as scissors or knives, but cannot readily be opened by children. 
         [0033]    While a blister package formed in accordance with the principles of the present invention is particularly shown and described herein with reference to the particular embodiment illustrated in the drawings, it is to be understood that the present invention may be used with many additions, substitutions, or modifications of form, structure, arrangement, proportions, materials, and components and otherwise, used in the practice of the invention, which are particularly adapted to specific environments and operative requirements without departing from the spirit and scope of the present invention as defined in the accompanying claims. In particular, it will be clear to those skilled in the art that the present invention may be embodied in other specific forms, structures, arrangements, proportions, and with other elements, materials, and components, without departing from the spirit or essential characteristics thereof. For instance, more than one product well may be provided in blister package  100 . Moreover, the blister package itself may be formed as an individual unit, or in a sheet, strip, matrix, or array of packages which may be joined for ready separation (such as by weakenings such as tear-apart perforations) into individual units. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and not limited to the foregoing description.