Tamper resistant package and method of making same

Abstract: The invention provides a package and associated method for packaging of products which enhances the resistanoe to tampering with or adulteration of the product, and which also permits a readily visible indication that any such tampering or adulteration has occurred. The invention in one form provides an inner container (4) which is in turn provided with an outer protective layer (6) of epoxide resin. The outer layer (6) is cured and it becomes extremely brittle such that any physical penetration of the outer layer will cause the entire outer layer to shatter. Such shattering will provide a clear indication that penetration of the protective layer (6) has occurred. Also there may be provided an associated dye which will exhibit a colour change when the outer protective layer is shattered. A warning message may be provided on said packaging underlying the outer layer. Use of the brittle material in a blister package is contemplated with or without an underlying packaging layer and other uses of the brittle material without support are contemplated.

Description: 1. Field of the invention This invention relates to tamper evident packaging and, more specifically, it relates to a tamper evident package and a method of sealing packages such that a clear indication would be given if any tampering occurs and more specifically the invention relates to a product which is coated with a layer of extremely brittle material that cannot be unsealed without completely shattering the packaging. Also provided is one embodiment of the present invention wherein part or all of the packaging is comprised of an extremely brittle material such that the packaging itself cannot be unsealed without completely shattering the packaging material. 2. Description of the prior art The tampering with and adulteration of many commercially available products has become a critical problem endangering health and sanitation. Many products which are adulterated or tampered with ultimately reach a consumer bearing no indication that such adulteration or tampering has occurred. Accordingly, it is highly desirable to provide a type of packaging which would give an indication that there has been interference with the integrity of the product packaging. Various mechanical indications used to determine the integrity of several type of products and containers have been known. For example, United States Patent No. 3,662,915 relates to a tamper evident package which provides a recessed tab in the inner periphery of a container which breaks away from the remainder of the container when entry is made into the container so as to indicate that tampering with the package has occurred. It has been known to employ elastomeric materials disposed in protective surrounding relationship with respect to a container. See United States Patent Nos. 4546881, 4449632 and 4181223 (the latter corresponding to the preambles of claims 1 and 6). United States Patent No. 2074490 discloses a tamper-evident container in the form of a tinplate container having a composite coating consisting of a heat sensitive paint, printing ink, and varnish. This coating is said to distort responsive to any effort to remove the can end, get access to the contents, and then solder the end to the can. It has been known to provide for rupturing of outer coatings which fracture responsive to operation of a tear strip. See United States Patent No. 3415402. See also United States Patent No. 4479585. It has been known to protect printed circuit boards by ultraviolet curable polymeric coatings which are intimately bonded to such boards. See United States Patent Nos. 4,451,523 and 4,424,252. In addition to such mechanical indicators, it has been known to provide a color indication that package integrity has been interrupted. For example, United States Patent No. 3,935,960 provides a hermetically sealed container having a tape closure over an aperture for removing the contents of the container. The tape closure is provided with an indicator layer of color capsules which rupture when the tape closure is removed. United States Patent No. 4,502,605 provides an indicator dye/activator system which is mounted on the cap of a container in such a way that opening the cap of the container causes the indicator material to oxidize and thereby change in color. It teaches the use of a volatile alkali solution such as ammonia as an activator having a pH in the range of 9-12 whereas atmospheric air has a pH in the range of 5-7. The preferred indicator dye is said to be phenolphthalein or other dyes sensitive to changes in the pH. See also United States Patent No. 4,516,679. United States Patent No. 4,098,577 also discloses use of a pH sensitive dye which will display a different color when in contact with atmospheric air which would occur when the package is opened. United States Patent No. 4,505,399 provides a sheet of material sensitive to light or oxygen which would effect a time-delayed, irreversible change in appearance in response to exposure. The sensitive material would be placed between two inactive sheets and the combination would be placed over the opening to the container so that the sensitive sheet would have to be exposed when the container is opened. Some of the problems which have been encountered in using the prior art techniques are that they can be circumvented by various means. In addition, the known methods are primarily confined to use with certain types and configurations of containers. In spite of the existing prior art techniques, there remains a need for an effective method of indicating that a product has been tampered with or altered. There remains a need for such a method which is economical and easy to use with a wide range of package configurations. It is among the objects of the invention to provide a package and method which will effectively and economically ensure that a visible indication will be provided if any tempering with or adulteration of the packaging of presently commercially available products has taken place. According to one aspect of the invention, there is provided a method of packaging a product comprising: providing a container, applying to said container an exterior coating material to form a protective layer on the exterior of said container, characterised in that said coating, after application, is subsequently cured so that the protective layer is caused to become brittle, and has a propensity to fracture irreversibly and at least in part to separate from said container in response to efforts to physically penetrate said layer, whereby readily visible indicia of such tampering will be provided. According to another aspect of the invention, there is provided a method of packaging a product comprising at least partially surrounding said product with an ultraviolet cured brittle material, whereby efforts to penetrate said material will irreversibly fracture said material and at least in part separate the material from the product. According to a yet further aspect of the invention, there is provided a tamper-evident package comprising a product and a packaging material at least partially surrounding said product, characterised in that said packaging material comprises a cured brittle material, whereby physical penetration of said cured brittle material will cause a readily visible irreversible change in said brittle material by fracture thereof and at least partial separation of the material from the product to provide evidence of tampering. It is also contemplated that a moisture or oxygen sensitive dye may be placed under the brittle layer or coating which would exhibit a distinctive change in coloration if anything has penetrated the brittle layer or coating. It is also contemplated in one embodiment that fracture of the brittle layer will expose an underlying warning. The method of the invention may be used with a variety of containers of different shapes, configurations, and materials without being limited to a particular package design. The preferred methods embodying the present invention are easy and economical to apply to a container. These and other objects and advantages will be more fully understood from the following description of embodiments of the invention with reference to the illustrations appended hereto. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a cross section of one embodiment of the device of the present invention wherein an outer package which holds an inner container is coated with the outer protective coating. Figure 2 illustrates a perspective view of one embodiment of the present invention after the outer coating has been shattered due to tampering or some other interference with package integrity. Figure 3 illustrates a cross section of a portion of the side wall of a package according to one embodiment of the present invention. Figure 4 illustrates a cross section of one embodiment of the present invention wherein the inner container of Figure 1 is coated exteriorly with the outer protective coating. Figure 5 illustrates a plan view of a blister package configuration of the present invention. Figure 6 illustrates a sectional view of the package along lines 6-6 of Figure 5. Figure 7 illustrates a sectional view of a blister package configuration of the present invention, wherein the upper layer of the packaging is comprised of the outer coating material without a substrate material. DESCRIPTION OF THE PREFERRED EMBODIMENT Tampering with and/or adulteration of food, drug, and medical products has become increasingly more common and the effects of such activities have become increasingly more dangerous to health and has in some instances have proved fatal. By providing packaging which readily exhibits to the naked eye the fact that a product has been tampered or interfered with, consumers can be put on notice and can avoid purchasing such products. According to the device and method of the present invention, a package is provided, preferably exteriorly, with a layer of extremely brittle material, as by coating. Preferably, the coating material would be an epoxide resin such as a cycloaliphatic epoxide manufactured by Union Carbide Corp. of Danbury, Connecticut, and sold under the trade designation CYRACURE, UVR 6110. Alternatively, the coating material could be a polyester base ultraviolet cured matte sold under the trade designation Polycure by Oriental Intl. of Tokyo, Japan, for example. As another alternative, a premixed ultraviolet light curable cycloaliphatic epoxide may be used such as, for example, those sold under the trade designation Envibar UV 1244 manufactured by the Union Carbide Corp. of Danbury, Connecticut. Other materials of the Envibar line, such as K 231 and K 232 and also UV 1231, for example are suitable. In order that the present invention be more fully understood some further details about the properties of the preferred materials will be given. In general, cycloaliphatic epoxide products such as those mentioned hereinbefore, are low-viscosity, miscible liquids that are easily combined. In order to obtain the appropriate properties with those materials, they must be combined with photoinitiators. The process of this combination is sometimes referred to as "formulation". A suitable class of materials are the onium salt photoinitiators. When onium salts are exposed to ultraviolet light they photolyze or chemically decompose under the action of light and generate a cationic species that acts as a catalyst and/or initiator for polymerization of cycloaliphatic epoxides. Suitable materials are those sold under the trade designations CYRA CURE EVI-6974 and CYRA CURE UVI-6990 by Union Carbide Corp. and UVE-1014 and UVE-1016 by General Electric Company. More specifically, the cationic chemistry involved in the curing of adhesives, coatings, inks, and sealants deals with onium salt photoinitiators. These photoinitiators are blocked catalysts that are unblocked by the action of ultraviolet light. When the salts are exposed to ultraviolet light, they photolyze and chemically decompose under the action of ultraviolet light. Subsequently, they generate into a cationic species that acts as a catalyst or an initiator for polymerization of cycloaliphatic epoxides. In the presence of the generated cationic species, very rapid polymerization takes place. The specific material mentioned above, UVR 6110, is a general purpose base epoxide that has an excellent cure response and viscosity differentiation that facilitates formulation. As stated herein, the epoxide materials respond to ultraviolet light cure when they are combined with an appropriate photoinitiator. Aryldiazonium salts and arylidonium salts are suitable photoinitiators. When the base epoxides, such as UVR 6110, are used alone as the only polymerizing ingredient in a formulation, hard, brittle coatings with good solvent resistance and adhesion result. This result is desirable for purposes of the present invention. If desired, a material containing the photoinitiator may be employed. One suitable material for this purpose is that sold by Union Carbide under the trade designation ENVIBAR 1244. In order to prepare the formulation, the various ingredients may be simply combined or stirred by simple mixing for a suitable period, and then the coating and curing procedures are undertaken. The process should preferably be carried out under "yellow" light conditions to protect the preparation from ultraviolet light until curing is performed. Some substances, such as the preferred material, Envibar UV 1244, discussed hereinbefore, are premixed with that the epoxide already contains the photoinitiators. Such one-step systems may be directly applied to the item to be protected and then cured. The coating which is preferably applied in generally uniform thickness may readily be accomplished by either dipping the product in the coating material or spraying the product with the desired coating material, for example. Alternatively, the material may be brushed onto the substrate. The layer of the appropriate liquid resin may be of any desired thickness depending upon the purpose for which it is to be used and the specific material to be used. For most purposes the thickness would, for example, preferably be of a thickness between about 25 microns (1.0 mil) and 1250 microns (50 mil) and is preferably between 25 and 375 microns (1.0 and 15 mils) when UVR 6110 or the like is used. When Envibar UV 1244 is used, the thickness would also preferably be between about 25 and 375 microns (1.0 and 15 mils). As discussed hereinafter, the brittle packaging material may be used alone to package a product. When employed alone the thickness would be preferably between about 50 and 2500 microns (2.0 mils to 100 mils). The coating material is preferably applied to the entire package exterior, but may be applied solely to certain critical areas. One or more overlying layers of packaging material may be applied if desired. In addition, a separation or release layer of silicon, tetra flouroethylene ("Teflon"), oily film, cellophane, or a thin nylon membrane, for example, may be applied to the package, if desired, to resist adherence of the molten epoxide to the underlying portion of the container to be protected. After the layer of liquid resin is applied to the package, the layer is then cured. It may preferably be cured, for example, by subjecting the package to a band of radiant ultraviolet light, for example. This may preferably be accomplished by exposing the product to a suitable medium, such medium would preferably be medium pressure mercury vapor from a suitable mercury vapor lamp which is known in the art. Alternatively, other methods of curing the coating layer may be used. The ultraviolet radiation required is preferably of an intensity of about 175 watts and it would be sufficient to expose the product to this radiation for at least about two seconds per three square feet of material. Other materials may require a shorter period of radiation exposure. As discussed herein, when the coating material is cured with the ultraviolet light and added to the epoxide, photoinitiators cause the molten epoxide to crystallize and the molten epoxide becomes hard and brittle as a result. Accordingly, any tampering with a product contained in this packaging will cause the outer epoxide shell of the packaging to shatter, portions of the shattered shell will tend to separate from the package and may break into separate pieces. EXAMPLES In order to provide additional insight into the present invention, three examples will be considered: Example 1 A sample coating comprised of cycloaliphatic epoxide (medium viscosity) UVR 6110 was mixed with a suitable photoinitiator, CYRA CURE UVI-5974 in the weight ratio of 4% (9674) to about 96% (6110). The coating material at a temperature of 64°F-80°F was then applied by spraying the material in a continuous coating using a spray nozzle onto the exterior of a sample container. A layer of a thickness of 2 mil was applied. The container as coated was then cured using ultraviolet light from a medium pressure mercury vapor source of an intensity of 175 watts for about 6 seconds. This process achieved a coating of a uniform thickness and was of the desired brittleness which was sufficient to achieve the objects of the present invention. Example 2 An example of a process employing a premixed epoxide, such as Envibar UV 1244, will be considered. A blistered top portion of a package may be precast using Envibar UV 1244 at a temperature of about 80°F. The product, such as a pharmaceutical in capsule form was introduced into recesses in the blistered top. A sheet of brittle matte was bonded to the top with Envibar UV 1244 being provided thereon. The entire package was then cured employing a medium pressure vapor lamp for about 6 seconds to provide a tamper-evident package. Example 3 A conventional commercial coating employed on individual cardboard cartons for tubes of medical ointments was tested. The coating applied in a conventional manner and commercial standard thickness including both ink and varnish had an overall thickness of about 2.5 to 5 microns (0.1 to 0.2 mils). Puncturing the container with a sharp instrument failed to create any coating fracture which was observable by the naked eye. This test confirmed the effectiveness of the tamper-evident material of the present invention over the tested conventional package. The present invention also contemplates an optional additional indicator, if desired, which would involve use of a moisture or oxygen sensitive dye as an additional indicator of tampering. Such dye would be placed under the chemical coating layer. A preferred dye would be hydroscopic alkaline, such as hypo. When that is used, no color change would be present if the outer coating or the packaging has not been broken. However, once the packaging is broken, air or oxygen may penetrate into the interior packaging. Once this occurs, a distinctive coloration change would occur and would be immediately and readily visible. It is contemplated that other types of dyes could be used within the bounds of the present invention. This color changing chemical would be an additional safety feature which would give a further indication that the product concerned had been subjected to tampering. In addition to the aforementioned safety features, it is contemplated that a tear strip would be provided to facilitate proper opening of the package. A pre-formed tear strip which has been treated with the appropriate coating material and properly cured could be placed on the package to function as an opening mechanism and also as an indicator of any tampering as tampering with the tear strip will break the chemical seal and will fracture the coating and other overlying packaging material. Referring now more specifically to Figures 1 and 2, one preferred embodiment of the device of the present invention will be discussed. Package 2 holds inner container 4. The package 2 is preferably completely covered by outer protective layer 6. Outer layer 6 may be a cycloaliphatic epoxide as discussed hereinabove. Inner container 4 holds contents 5 which may be pharmaceutical products such as capsules or tablets, for example. Tear strip 8 is provided to facilitate ease of opening of the package. By simply pulling the tear strip 8, outer protective layer 6 is shattered. It will be appreciated that as the outer protective layer 6 overlies the tear strip 8, the tear strip cannot be operated without shattering the layer 6. This shattering without operation of tear strip 8 is illustrated in Figure 2 where outer protective layer 6 is shattered into a plurality of individual pieces 10 by some form of physical penetration. Physical puncturing with a needle, or any attempt to open or interfere with package 2 results in fracture of layer 6. As noted above, a dye could also be used in addition to protective layer 6 to further enhance the likelihood that any product with which any tampering has occurred will be avoided. As is shown in Figure 2 when the outer protective layer 6 is shattered at least some portions thereof separate from the portion of the package 2 to which it had been secured. Some of such separated portions 10 may also separate from other portions of layer 10. In either event there is provided a tangible, readily visible indication of tampering. In lieu of having the message obscured by an opaque puncture layer 6, one may provide both the layer 6 and message of generally the same color which color contrasts with the underlying package component on which it appears. Figure 3 shows the sidewall of a package 2 in further detail. Package 2 has wall 12 which has outer protective layer 6 thereon. The indicator dye (not shown) could be placed between wall 12 and layer 6. One embodiment of the present invention may also include intermediate release layer 14 which keeps the molten epoxide from adhering to the sidewall 12 of package 2 in cases where such adherence of the epoxide resin could be undesirable. The package 2 as shown in Figure 1 is provided with the outer coating of the protective material. However, it is also contemplated and would be within the scope of the present invention that, as shown in Figure 4 for example, a container, such as inner container 4, may be directly coated with or be composed entirely of the protective material with or without the use of an external container such as container 2. If desired, an enhanced visual indication may be provided by providing words or graphics or both as a warning indicator which would be visible only if tampering has occurred. For example, the words "IMPURE DO NOT USE" could be provided in a number of locations on the package 2 of Figure 2 in positions underlying outer protective layer 6 such that layer 6 will conceal the message unless tampering has occurred. In Figure 2 for example, the exposed portions of package 2 shows underlying tear strip 8 could contain such legends. Alternatively, the outer coating 6 could be used, as shown in Figures 5 and 6, for example, with a "blister" packaging commonly used for packaging individual capsules or tablets. The blister packaging has first layer 16 and second layer 18. Sandwiched between first layer 16 and second layer 18 are tablets 5. A tear strip 8 may also be provided for ease of opening. This entire assembly is coated exteriorly with outer protective coating 6 and is then cured according to the present invention. When the tear strip is pulled, protective coating 6 shatters. Figure 7 depicts another embodiment of the present invention wherein the outer layer 6 is precast and comprises the upper layer or wall of the blister package without an underlying layer of packaging material. Second layer 18 is depicted in Figure 7, but it is also contemplated to be within the scope of the present invention that layer 6 could be precast to form the entire packaging of the products without the need for a substrate such as layer 16 of Figure 6 or layer 18 of Figures 6 and 7. Alternatively, the brittle layer could be used on the interior of an outer packaging such as cardboard or plastic for example within the bounds of the present invention. As noted herein, the container to be packaged according to the present invention may contain pharmaceutical products. Alternatively, the packaging of the present invention could be used for a wide variety of products wherein package integrity is important. Examples of such other uses are medical instruments and other products which must remain sterile until opened and food products. In a preferred embodiment of the invention in instances where the brittle material is adjacent to and bonded to a packaging component the bonding action will be sufficiently small that fracturing of the brittle material by tampering will tend to sever such bonds to facilitate separating of the brittle material from the package material. To the extent to which portions of such material which has separated from the package also separates from adjacent portions of the brittle material pieces, such as pieces 10 in Figure 2 will fall off. It will be appreciated that while for convenience of disclosure reference has been made herein to the cured material completely surrounding the product, it will be appreciated that in some instances a cooperating packaging component may be sufficiently impenetrable that the cured material will not be employed in the region of the package where such a packaging component is located. In some uses, it will be desired to protect solely the portion of the package which is designed to be the point of entry or opening during normal usage. It will be appreciated that in embodiments wherein the brittle layer is to be established by applying a layer to another packaging component this may readily be accomplished by any means such as spraying, brushing, or dipping. It will further be appreciated, therefore, that the present invention provides a package and associated method for packaging products which provides an irreversible, ready indication that the package has been subjected- to tampering or interference. Whereas particular embodiments of the invention have been described above for purposes of illustration, it will be appreciated by those skilled in the art that numerous variations of the details may be made without departing from the invention as described in the appended claims.

Claims: A method of packaging a product comprising: providing a container (4), applying to said container (4) an exterior coating material to form a protective layer (6) on the exterior of said container, characterised in that said coating (6), after application, is subsequently cured so that the protective layer is caused to become brittle, and has a propensity to fracture irreversibly and at least in part to separate from said container in response to efforts to physically penetrate said layer, whereby readily visible indicia of such tampering will be provided. The packaging method of claim 1, including the step of curing said layer (6) by applying ultraviolet radiation from a suitable source. The packaging method of claim 2, wherein said coating material (6) is an ultra-violet curable cycloaliphatic epoxide resin. The packaging method of claim 2, wherein said protective layer is applied in a thickness of 25 micron to 375 micron (1.0 to 15 mils). The packaging method of claim 4, including providing warning markings on said package (2) underlying said protective layer (6), said warning markings being provided so as to be not readily visible through said protective layer. A tamper-evident package comprising a product (4, 5) and a packaging material (6) at least partially surrounding said product, characterised in that said packaging material comprises a cured brittle material (6), whereby physical penetration of said cured brittle material will cause a readily visible irreversible change in said brittle material (6) by fracture thereof and at least partial separation of the material (6) from the product (4, 5) to provide evidence of tampering (7). The tamper-evident package of claim 6, wherein said product includes a container (4) and wherein said brittle material comprises a cured brittle layer (6) on said container, whereby any physical penetration of said layer will cause a readily visible, irreversible change in said layer through separation of at least portions of said brittle layer (6) from said container (4). The package of claim 6 wherein said cured brittle material itself forms a container for said product. The package of claim 7, including an indicator substance disposed between said container (4) and said layer (6), whereby upon any physical penetration of said layer (6), the indicator substance undergoes a readily visible irreversible change in coloration. The package of claims 6 to 8, wherein said cured brittle material is an ultra-violet cured cycloaliphatic epoxide resin. The package of claim 7, wherein said protective layer (6) is about 25 micron to 375 micron (1.0 mil to 15 mils) in thickness. The package of claim 6, wherein said protective layer (6) defines at least a portion of one wall of said package. The package of claim 7, wherein a warning message is provided on said inner container underlying said protective layer. The package of claim 7 wherein said brittle layer (6) is applied to a release layer (14), in turn applied to said container. A method of packaging a product (5, 18) comprising at least partially surrounding said product (5, 18) with an ultra-violet cured brittle material (6), whereby efforts to penetrate said material (6) will irreversibly fracture said material and at least in part separate the material from the product (5, 18). The method of claim 15 wherein said ultra-violet cured brittle material comprises a cycloaliphatic epoxide resin.

Inventors: CURIEL YORAM, CURIEL, YORAM
Applicants: TSL INC, TSL INCORPORATED
Application year: 1990
Main classification: B65D25
IPC codes: B65D55, B65D77, B65D25