WO1995005323A1

WO1995005323A1 - Tamper resistant package and method of making same

Info

Publication number: WO1995005323A1
Application number: PCT/US1993/007669
Authority: WO
Inventors: Yoram Curiel
Original assignee: TSL Inc
Current assignee: Opsec Security Group Inc
Priority date: 1993-08-16
Filing date: 1993-08-16
Publication date: 1995-02-23
Anticipated expiration: 1996-02-16
Also published as: AU5012793A

Abstract

Tamper evident elements and associated methods of making tamper evident elements and associated methods of making structural members with tamper evident elements are disclosed. The tamper evident elements are made of a cured brittle resin (24) which, when tampered with, will be caused to undergo a readily visible, irreversible change.

Description

TAMPER RESISTANT PACKAGE AND METHOD OF MAKING SAME

BACKGROUND OF THE INVENTION

1. Field Of The Invention This invention relates to tamper evident elements, such as labels, and associated methods of making tamper evident elements as well as to structural members, such as containers, having tamper evident elements and associated methods of making structural members with tamper evident elements.

2. Background Information

The tampering with and adulteration of many commercially available products have become critical problems endangering health and destroying purity of many products. Many products which are adulterated or tampered with ultimately reach a consumer bearing no visible indication that such adulteration or tampering has occurred. Accordingly, it is highly desirable to provide a type of packaging which would give a reliable visual indication that there has been interference with the integrity of the product packaging.

My United States Patent No. 4,890,763, the disclosure of which is expressly incorporated herein by reference, discloses a tamper resistant package and a method of making the same. An outer protective layer of an epoxide resin is placed on a package and is subsequently cured by ultraviolet radiation. This causes the outer layer to become extremely brittle such that any physical penetration of the outer layer will cause the outer layer to shatter. Such shattering will provide a clear visual indication that penetration of the protective layer has occurred as by fracturing of the material and separation of the pieces from the package. My patent also discloses providing a warning message printed on the package underlying the cured brittle resin which becomes visible upon pieces of the resin separating from the package.

My United States Patent No. 5,028,290 discloses a method of applying a tamper evident label to a package. The method comprises providing a carrier tape having recesses, depositing a resin into the recesses and treating the resin to produce a label having an adhesive portion. The label is separated from the carrier tape and secured to the package. The method further comprises curing the label on the package to create a tamper evident label. This patent also discloses providing a warning message printed on the package underlying the label that is placed on the package. The warning message becomes visible upon pieces of the resin separating from the package.

Commonly owned United States Patent Application Serial No. 07/545,530 filed June 29, 1990 discloses a tamper evident package comprising a container and an exterior packaging material at least partially covering the container. The exterior packaging material consists of a cured brittle photopolymerizable composition on a backing film. The photopolymerizable material is the same material that was disclosed in my earlier United States Patent No. 4,890,763. The patent application states that the brittle photopolymerizable material will fracture and at least in part separate from the container upon physical penetration of the exterior packaging material. The patent application discloses several embodiments of the exterior packaging material including providing a pressure sensitive adhesive ("PSA") backing with a release sheet disposed adjacent to the photopolymerizable material as well as providing a printing ink layer disposed beneath the photopolymerizable material.

The exterior packaging materials disclosed in commonly owned United States Patent Application Serial No. 07/545,530 are made by a lamination process. This involves a number of separate processing steps. First, the uncured photopolymerizable resin is deposited on a wax paper release sheet. The sheet with the resin is dried in an oven and then rolled into a coil and set aside or transported to the location where it will be further processed. A backing film having a PSA layer disposed on one side thereof which is protected by a release sheet must also be provided. The backing film/PSA composite is processed by a printing machine to print indicia on the backing film. After the printing ink dries (approximately 24 to 48 hours) , the hereinbefore mentioned sheet with the photopolymerizable material and the printed backing film/PSA composite are then laminated to each other to form the tamper evident label. Lamination of the two components is achieved through conventional lamination techniques involving conventional lamination apparatus. After this, the release sheet on the photopolymerizable material must be removed and discarded before the label is applied to a container.

As can be appreciated, the lamination process is time consuming and involves several steps. The lamination process can also involve preparing the sheet with the photopolymerizable material at a separate location and the subsequent transporting of that sheet to the location where the lamination is done. Of course, the lamination process involves providing a lamination apparatus and all of the attendant costs necessary with a lamination operation. Finally, the release sheet on the photopolymerizable material is discarded after the lamination process is completed. This adds costs to the production of the tamper evident label as well as creating excess waste paper. The excess waste paper must be disposed of in landfills, and as the waste paper is silicone coated or made of a polyester material, this material is not readily biodegradable, which contributes to the growing problem of controlling landfill waste.

It has also been found that the lamination process creates air bubbles in the resin of the end product label that is produced. This is because when the resin is dried over silicone coated films some of the solvents are not able to be fully evaporated. Lack of this evaporation creates air bubbles and imperfections in the resin layer which results in a cloudy appearance in the resin layer when the label is finally applied to the container. This not only is unsightly but also can make it harder to read the underlying container package.

Thus, despite the hereinbefore methods and products, there still remains a need for an improved tamper evident label that can be placed on a container which will indicate whether tampering with the container has occurred.

SUMMARY OF THE INVENTION The tamper evident structural member has met the above identified needs. The tamper evident structural member comprises a structural member and a tamper evident element at least partially covering the structural member disposed adjacent to the exterior of the structural member. The tamper evident element comprises a cured brittle resin layer containing indicia and a PSA layer secured to the cured brittle layer. A readily visible irreversible change in the cured brittle layer will occur upon any tampering with the tamper evident label or the structural member. The method of providing a structural member having a tamper evident element comprises providing a structural member, providing a removable film material having indicia thereon and applying a curable resin layer on the film such that the indicia is adhesively bonded to said curable resin layer from the removable film material. The method further comprises drying the curable resin layer to evaporate the solvents therein, applying a PSA layer on the dried curable resin layer and removing the film from the curable resin layer. The method finally comprises placing the element on the structural member by securing the PSA layer thereto and curing the curable resin layer.

In another embodiment of the invention, the tamper evident element for use on a structural member comprises a film having a first surface and a second surface, the first surface having secured thereon a first patch and the second surface having secured thereon a second patch. The second patch defines an area which forms a message and the first patch overlies the second patch so that the message of the second patch is not visible. The element further comprises a cured brittle resin layer in overlying contact with the first patch such that tampering with the element or structural member will cause the layer to fracture and at least in part separate from the film so that at least a portion of the message is visible. Associated methods of making a tamper evident element for use on a structural member and for providing a structural member having a tamper evident element and an associated method are also provided. A further embodiment of a tamper evident element for use on a structural member in accordance with the invention is also provided. The tamper evident element comprises a film having a first surface and a second surface and a cured brittle resin applied to at least a portion of the film. The film has at least one non-bonded region wherein the resin is not adhesively bonded to the film. As with the hereinbefore mentioned tamper evident element, tampering with the tamper evident label will cause the cured brittle resin layer to fracture or at least in part separate from the film. The separation is facilitated by the non-bonded region. Associated methods of making a tamper evident element for use on a structural member and for providing a structural member having a tamper evident element and an associated method are also provided. It is an object of the invention to provide a tamper evident label that will display a warning message to a consumer indicating that tampering with a package has occurred.

It is a further object of the invention to provide a tamper evident label that can be made without resorting to costly and inefficient lamination processes.

It is still a further object of the invention to provide a tamper evident label in which the brittle resin will separate from the container upon tampering in a controlled and predictable manner. It is still another object of the invention to provide a tamper evident label in which the resin coating is free from air bubbles and other imperfections.

These and other objects of the invention will be more fully understood from the following description of the invention with reference to the drawings appended to this application.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front elevational view of the backing film showing the printed indicia thereon.

Figure 2 is a side view of the backing film showing the printed indicia thereon.

Figure 3 is a side view of the embodiment of the tamper evident label with the backing film still placed thereon.

Figure 4 is a side view of the embodiment shown in Figure 3 only with the backing film removed.

Figure 5 is a front elevational view of the embodiment shown in Figure 4. Figure 6 is a perspective view of a container which has the tamper evident label of Figure 4 placed thereon.

Figure 7 is a perspective view of the container of Figure 6 after tampering with the label has occurred. Figure 8 is a cross-sectional view of another embodiment of the invention showing a film having a first and second printing patch.

Figure 9 is a top plan view of the embodiment of Figure 8 showing the film and the first printing patch. Figure 10 is a bottom plan view of the embodiment of Figure 8 showing the film and the second printing patch.

Figure 11 is a cross-sectional view of one embodiment of the tamper evident label of the invention. Figure 12 is a perspective view of a container which has the tamper evident label placed thereon.

Figure 13 shows the container of Figure 12 after tampering with the label has occurred. Figure 14 is a cross-sectional view of another embodiment of the tamper evident label showing a film having two non-stick material areas disposed thereon.

Figure 15 is a top plan view of the portion of the label shown in Figure 14.

Figure 16 is a cross-sectional view of the label shown in Figure 14 showing the resin applied thereto. Figure 17 is a cross-sectional view of the embodiment of the tamper evident label shown in Figure 14 with the PSA and release sheet applied thereto.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As is used herein, the term "structural member" means any physical structure consisting of one or more components which are to be employed in combination with the other features of the present invention, including but not limited to containers, multipiece articles having relatively movable parts such as doors and desks or video cassettes or envelopes. The structural member may be made from a variety of materials including but not limited to paper, foil, hard and soft plastic, hard and soft rubber, wood, metal, and combinations of the foregoing.

As used herein, the term "tamper evident element" means any article that is adapted to be in contact with or secured on a structural member, such as, for example, a label.

As used herein, the term "indicia" means any visually perceptible contrasting portion of a tamper evident label which may be created by any suitable means, such as, for example, by printing. As used herein, the terms "tampering" or

"tampering with" means applying a force to a structural member or a tamper evident element, including, without limitation, moving a structural member, removing a tamper evident element from a structural member or physically penetrating a structural member.

Referring to Figures 1 and 2, a backing film 20 is shown having indicia in the form of printing 22 thereon. The printing thereon are the words "TAMPER SAFE" however, any words or logos in any shape, size or color can be made on the backing film 20. In this embodiment, the printing on the backing film is done first. The printing is adhered on the backing film such that the printing will preferably fail the so-called "scotch tape" test used in the label industry. Under this test, a piece of transparent scotch tape is placed over the printed area. The scotch tape is then removed from the printing. If the printing 22 is removed from the backing film 20 along with the scotch tape, the printing 22 on the film 20 is said to fail the scotch tape test. Thus, the printing 22 is not strongly adhesively bound to the backing film 20.

Once the backing film 20 is printed with indicia 22, a curable resin layer 24 is applied to the surface of the backing film 20 containing the indicia 22 (Figure 3) . The curable resin layer is made of the materials described in commonly owned United States Patent Application No. 07/545,530, which is expressly incorporated herein by reference. The curable resin layer 24 is applied by casting the curable resin material over the backing film or by other methods which are described in my United States Patent No. 4,890,763, which is also expressly incorporated herein by reference. The curable resin layer 24 is transparent and is about 2 to 7 mils in thickness.

Because the printed indicia 22 is not firmly bound to the backing film 20, the printed indicia 22 will adhesively bond to the curable resin layer 24 after the curable resin layer 24 is cast upon the backing film 20. This is because the curable resin layer 24 has adhesive qualities, thus when the curable resin layer 24 is in molten form (before drying, as will be explained further hereinafter) the indicia 22 is, in effect, adhesively bonded to the curable resin layer 24. After casting, the curable resin layer 24 is dried so as to evaporate the solvents therein. The drying of the curable resin layer 24 is accomplished by subjecting the curable resin layer to temperatures of about 100°F to 160°F for about 5 to 10 seconds. In practice, this is accomplished by transporting the packing film/resin composite through a heating tunnel. It will be appreciated that thermoset resins can be used as the material for the curable resin layer 24. The thermoset resins are dried at a first temperature and then cured at a second, higher temperature. In addition, a two-stage ultraviolet cure resin can be used, as was disclosed in my United States Patent No. 5,028,290, the disclosure of which is also expressly incorporated herein by reference.

A PSA layer 26 is then applied to the dried resin layer. The PSA is applied to a thickness of 0.4 to 1 mils by conventional means well known to those skilled in the art. After the PSA is applied, a release sheet 28 is placed on the PSA layer 26. The release sheet is made of silicone coated polyester, for example, and is approximately 1 to 4 mils thick. As is well known, the release sheet 28 allows for storage and transportation of the labels until such time as the release sheet 28 is removed and the label placed on a container.

In accordance with the invention, the backing film 20, whose printed indicia 22 has been absorbed into the curable resin layer 24, is removed and the filmless label 30 shown in Figures 4 and 5 is produced. The backing film 20 can be used again to print indicia thereon, and to produce more tamper evident labels. This eliminates the costs of providing backing film 20 for each label. Also, this reduces waste which must be discarded in landfills.

The label 30 is then ready to be applied to a container, such as container 32 shown in Figures 6 and 7. The label 30 is placed on the container 32 by conventional label applying apparatus well known to those skilled in the art. The curable resin layer 24 with indicia and PSA layer 26 is separated from the release layer 28, and the PSA layer 26 is placed in surface-to-surface contact with the container 32 such that the label 30 is adhesively secured to the container 32 as shown in Figures 6 and 7. Once the label 30 is disposed on the container 32, the label 30 is cured by exposure to ultraviolet light. This will convert the curable resin layer 24 into a cured brittle layer 34 such as is shown in Figures 6 and 7. As can be seen in Figure 6, the indicia TAMPER SAFE 22 is visible through the cured brittle layer 24 on the label 30 of the container 32. Once tampering with the label 30 or container 32 is made, the cured brittle resin will fracture (or "craze") as shown in Figure 7. This is an irreversible, readily visible change in the label 30 which indicates to a consumer that tampering has occurred. In addition, to the crazing and fracturing, but not necessarily so, a portion 36 of the cured brittle resin may at least in part separate from cured brittle layer 34. This will give further indication of tampering, as a portion of the indicia 22 will be missing (the "F" and "E" of SAFE as shown in Figure 7) .

The label 30 is preferably used with rigid structural members in that the label 30 will remain more intact during shipping and handling.

It will be appreciated, therefore, that the method of making a tamper evident element for use on a structural member as shown in Figures 1-5 comprises providing a removable film material having indicia thereon and then applying a curable resin layer on the film such that the indicia is adhesively bonded to the curable resin layer from the film. The method further comprises drying the curable resin layer to evaporate the solvents therein and applying a PSA layer on the dried curable resin layer. A release sheet can optionally be provided on top of the PSA layer. The method finally comprises removing the film from the curable resin layer such that, upon curing of the curable resin layer, tampering with the tamper evident label will cause a readily visible, irreversible change in the cured brittle layer. The method of the invention further contemplates providing a structural member having a tamper evident element. This method comprises providing a structural member (Figures 5 and 6) and providing a removable film material having indicia. A curable resin layer is applied to the film such that the indicia is adhesively bonded to the curable resin layer from the removable film material. The curable resin layer is subsequently dried to evaporate the solvents therein. The method further comprises applying a PSA layer to the dried curable resin layer and removing the film from the curable resin layer. The method finally comprises placing the tamper evident element on the structural member and curing the curable resin layer to create a cured brittle layer on the structural member. In another embodiment of the filmless label method described hereinbefore, instead of printing indicia 22 on the backing film 20, the indicia 22 can be printed after the resin has been casted and dried on a blank backing film and the PSA and release sheet applied to the dried curable resin. In this way, custom printing of a relatively few number of labels can be accomplished.

Referring now to Figures 8-11, another embodiment of the tamper evident label will be discussed. The tamper evident element shown is a label consisting of a film 50 made of acetate or polypropylene and preferably about 1 to 2 mils in thickness. The film 50 is preferably transparent, so that upon application to the package to be protected, the film will not be visible to the consumer.

The film 50 has a first surface 52 and a second surface 54. Printed on the first surface 52 is a first printing patch 56. This first printing patch 56 has the same color as the portion of the structural members on which the first patch 56 will be placed. For example, if the portion of the structural member on which the tamper evident element will be placed is blue in color, the color of the printing of the first printing patch 56 will also be blue. Completely underlying the first printing patch 56 is a second printing patch 58. As can be seen in Figure 10, second printing patch 58 consists of an area 60 of contrasting color to the first printing patch 56 (such as a white area 60 as shown in Figure 3) . This area 60 defines a warning message 62, such as "VOID". The warning message can be words, symbols or even contrasting colors. It will be appreciated that the contrast between area 60 and the underlying blue structural member and the overlying blue first printing patch 56 will set off and form the warning message 62. The printing patches 56 and 58 are printed on the film by printing machines which are well known to those skilled in the printing art. For example, printing patches 56 and 58 are printed on film 50 in registration on both sides of the film 50, respectively, and at the same time.

It will be appreciated that printing patch 56 is disposed on top of film 50 and printing patch 58 is disposed on the underside of film 50. This is done to prevent "wiping off" the exposed message without tearing the package apart. It will also be appreciated that the film 50 before printing can be subject to a "corona treatment" which process is well known to those skilled in the art whereby the film is exposed to an electrical charge which makes the film more receptive to the printing patches. Referring now to Figure 11, after the film 50 is printed, a PSA layer 72 is applied to the second surface 54 and a release sheet 74 is applied to the underside of the PSA layer. After this, a resin layer 70, made up of the resin described in commonly owned United States Patent Application 07/545,530 is applied to the first surface 52.

The PSA layer 72 and release sheet 74 are preferably applied before the resin layer 74 in order to provide a solid "platform" on which to apply the resin layer 74, as the resin layer 74 is comparatively heavy. The resin layer 70 is applied so as to completely cover the first printed patch 56. The resin layer 70 can be applied by the methods discussed in United States Patent No. 4,890,763 and is about 2 to 7 mils in thickness. The tamper evident element can be peeled from the release sheet 74 and placed on the structural member to create the tamper evident protection for the structural member. The printing ink which makes up the first printed patch 56 will be adhesively bonded from the film 50 to the resin layer 70. It will be appreciated, therefore, that the resin layer 70 overlying the first printed patch 56 will turn the color of the first printed patch 56. For example, if the printed patch 56 is blue in color, the resin layer overlying the first printed patch 56 will also be blue. If the container to which the label is applied is blue, the resin layer 70 overlying the first printed patch will be almost imperceptible on the package. This is an important consideration in consumer packaging, in that the tamper evident label will not interfere with design or construction of the package until such time as tampering has occurred.

After this, the resin layer 70 is dried to remove the solvents from the resin. This step is accomplished by passing the film containing resin layer through a heating tunnel. The temperature in the heating tunnel ranges from 100°F to 160°F. This will evaporate the solvents in such a manner that undesired air bubbles are not formed in the resin layer. Once the label is placed on the container, the label is cured so as to produce a cured brittle layer. The curing is effected by using an ultraviolet light source means such as is disclosed in my United States Patent No. 5,028,290. The curing can be done immediately after the resin is dried, or after the label is placed on a container or by a portable ultraviolet curing source after the label is placed on a structural member. For example, the uncured label may be applied so that one portion thereof is placed on a door and the other portion on the door jamb. The portable ultraviolet light source can then be used to cure the resin layer " in situ". This resin layer will indicate whether the door has been tampered with. As was disclosed in my United States Patent No. 4,890,763, the ultraviolet curing converts the resin layer into a cured brittle layer. The cured brittle layer is characterized by a propensity to fracture and/or at least in part separate from the film backing 50 upon efforts to remove or physically penetrate the label. In use, then, once the tamper evident element is applied to the structural member and is cured, tampering with the tamper evident element or the structural member will result in fracturing the label and pieces of the cured brittle layer separating from the film 50.

Referring now to Figures 12 and 13, a package 90 having a tamper evident label 111, such as discussed hereinbefore, applied according to the method of the invention is shown. The package 90 shown is a conventional container for medicines or the like and consists of a lid 122 hingedly connected to a base 124. As shown in Figures 12 and 13, the container 90 is blue in color. A seam 126 is created between the lid 122 and the base 124. The tamper evident label 111 is placed so that one portion 130 overlies the lid 122 and another portion 132 overlies the base 124. The label 111 is bonded to the package so that portion 130 is generally perpendicular to portion 132. This, of course, will prevent opening the lid 122 without fracture of the cured brittle resin. The label 111 has a transparent portion 136 and a blue portion 137. The blue portion 137 is the part of the resin layer overlying the first printing patch.

Figure 13 shows what happens when tampering with the package has occurred. If tampering occurs, the blue portion 137 of the resin layer will fracture and at least in part separate from the container. Pieces 141 of the resin layer are shown separated from the container in Figure 13. This will reveal the underlying message "VOID" 142 formed by the second printing patch of the tamper evident label 111. This message will warn the consumer that tampering with the container 90 has occurred. It will be appreciated that any tampering, such as penetration by a needle to outright opening of the container, will cause the label 111 to fracture and at least in part separate from the container 90 which will result in revealing the message "VOID" 142. It will be appreciated, therefore, that the method of making a tamper evident element for use on a structural member as shown in Figures 8-11 comprises providing a film having a first surface 52 and a second surface 54, applying a first patch 56 on the first surface 52 and a second patch 58 on the second surface 54. The second patch 58 defines a message, such as "VOID" 62. The method further comprises applying a curable resin layer 70 on the first patch 56 so that upon curing of the curable resin layer 70, tampering with the tamper evident element or the structural member will cause the layer to fracture and at least in part separate from the film so that at least a portion of the message is visible.

The method of the invention further comprises providing a structural member having a tamper evident element. This method comprises providing container 90 and providing a film 111 having a first surface and a second surface. The method further comprises applying a first patch on the first surface and applying a second patch on the second surface, the second patch defining an area which forms a message. A PSA is then applied to the second surface and a release sheet is then applied to the PSA. The method further comprises applying a curable resin layer to the first patch, drying the resin layer and placing the label on the container, removing the release sheet and placing the PSA layer on the container. The label is subsequently cured so that the curable brittle resin layer becomes brittle, whereby tampering with the tamper evident label or the structural member will cause the layer to fracture and at least in part separate from the film so that the message is visible.

Figures 14-17 show another embodiment of the tamper evident label of the invention. In this embodiment. the separation of the pieces of the cured brittle layer from the structural member on which it is applied is accomplished in a controlled manner. This embodiment comprises a film 200 having a first surface 202 and a second surface 204. The film 200 is similar to film 50 as was shown in Figures 8-11. Deposited on the first surface 202 of the film 200 is a plurality of non-stick areas 206. As shown in Figure 14, these non-stick areas 206 are protruding from the first surface 202 of the film 200 although it will be appreciated that the non-stick areas can be coplanar with the first surface 202 of the film 200. As shown in Figure 15, the non-stick areas 206 are in the form of rectangles. These non-stick areas 206 are composed of well known non-stick substances such as silicone, tetrafluorethylene, or other materials which are generally known to those skilled in the art as separation break coats. In addition, the non-stick areas can be made of a vacuum deposited metal coating. These areas 206 are deposited on the film by an apparatus well known to those skilled in the art. After the non-stick areas 206 are deposited on the film 200, a resin layer 210, similar to resin layer 70, is placed on the first surface 202 and the non-stick areas 206 as is shown in Figure 16.

It will be appreciated that the film can contain integral non-stick areas which may or may not protrude from the first surface thereof. In addition, the non-stick areas can assume any shape or size desired. The invention contemplates any means of creating a non-stick portion on the film. The non-stick portions create non-bonded regions wherein the resin is not adhesively bonded to the non-stick portions.

The embodiment discussed in Figures 14-16 can be used in conjunction with the embodiment disclosed in Figures 8-11. Figure 17 shows a label comprised of a film 302 having a first surface 304 and a second surface 306. Disposed on the first surface 304 is first printing patch 310 and overlying the first printing patch 310 is a non-stick deposit 312. A resin layer 314 is applied on the first surface 302 and over patch 310 and non-stick deposit 312. A second printing patch 320 underlies first printing patch 310 and is similar to second printing patch 58 in that it has an area in a contrasting color to first printing patch 310 which defines a warning message such as "VOID". A PSA 330 and a release sheet 332 are disposed on the second surface 306. As with the embodiment in Figures 8-11, any tampering with the label will cause the cured brittle resin layer to fracture and separate from the label. Upon tampering with the label, the non-stick areas will facilitate more controlled breakage and separation of the pieces of the cured brittle layer. As will be appreciated, the resin, before curing, will not be bonded as tightly to the non-stick areas as to the areas of the film devoid of the non-stick areas. Thus, the resin layer will have a propensity to more cleanly and in a more controlled manner fracture and separate from the label at the non-stick areas. In the embodiment of Figure 17, the non-stick deposit 312 insures that the cured brittle resin disposed thereon will fracture and separate from the label. This will expose the warning on second printing patch 320 which will indicate that tampering with label has occurred.

It will be appreciated that the method of making a tamper evident element for a structural member as shown in Figures 14-17 comprises providing a film having a first and second surface, and applying a curable resin layer on at least a portion of said first surface. The method further comprises establishing on the first surface at least one non-bonded region wherein the resin layer is not adhesively bonded to the film. Upon curing of the curable resin layer, tampering with the tamper evident label will cause the cured brittle resin to fracture and at least in part separate from the film, the separation being facilitated by the non-bonded region. The method of the invention further comprises providing a structural member having a tamper evident element. This method comprises providing a structural member and a film having a first surface and a second surface. A PSA layer is applied on the second surface and a release sheet is applied to the PSA layer. The method further comprises applying a curable resin layer to at least a portion of the first surface and establishing on the first surface at least one non-bonded region wherein the curable resin layer is not adhesively bonded to the film. The curable resin layer is dried so as to evaporate the solvents therein and the label is placed on the container by removing the release sheet and placing the PSA layer on the container. Finally, the element is cured to cause the resin layer to become brittle whereby tampering with the tamper evident element or the structural member will cause the cured brittle resin to fracture and at least in part separate from the film, the separation being facilitated by the non-bonded region.

It will be appreciated that the labels described hereinbefore can be used on any type of packaging including containers for pharmaceutical products, medical instruments and food products, for example. The labels can also be used on blister-type package holding pharmaceutical products, for example, or flexible packaging such as bags containing food products such as potato chips and pretzels. Finally, the labels can be used to indicate tampering with objects such as police evidence in storage or videocassettes.

It will be appreciated, therefore, that the present invention provide tamper evident elements and associated methods of making tamper evident elements. The invention also provides structural members containing tamper evident elements and associated methods of making structural members with tamper evident elements.

Whereas particular embodiments of the invention have been described above for purposes of illustration, it wiil 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

WHAT IS CLAIMED IS:

1. A tamper evident structural member comprising: a structural member; and a tamper evident element at least partially covering said structural member disposed adjacent to the exterior of said structural member, said tamper evident element comprising: a cured brittle resin layer containing indicia; and a pressure sensitive adhesive layer secured to said cured brittle layer to said structural member, whereby tampering with said tamper evident element or said structural member will cause a readily visible, irreversible change in said cured brittle layer.

2. The member of Claim 1, wherein said structural member is substantially rigid.

3. The member of Claim 2, wherein said structural member is made of materials selected from the group consisting of metal, wood and hard plastic.

4. The member of Claim 3, wherein said structural member is a container and said tamper evident element is a label.

5. The member of Claim 4, including said cured brittle resin layer is characterized by a propensity to fracture and at least partially separate from said structural member upon tampering with said structural member or said tamper evident label.

6. The member of Claim 6, wherein said indicia is a warning message.

7. The member of Claim 1, wherein said layer is comprised of a resin.

8. The member of Claim 1, wherein said cured brittle layer is about 2 to 7 mils thick.

9. A method of providing a structural member having a tamper evident element, said method comprising: providing a structural member; providing a tamper evident element made in accordance with the following method: providing a removable film material having indicia thereon; applying a curable resin layer on said removable film material such that said indicia is adhesively bonded to said curable resin layer from said removable film material; drying said curable resin layer to evaporate the solvents therein; applying a pressure sensitive adhesive layer on said dried curable resin layer; and removing said removable film material from said dried curable resin layer; placing said tamper evident label on said structural member by securing said pressure sensitive adhesive layer thereto; and curing said dried curable resin layer, whereby tampering with said structural member or said tamper evident element will cause a readily visible, irreversible change in the cured resin layer.

10. The method of Claim 9, including employing as said structural member a container and employing as said tamper evident element a label.

11. The method of Claim 10, including after applying said pressure sensitive adhesive layer to said curable resin layer, applying a release sheet on said pressure sensitive adhesive layer; and before placing said tamper evident label on said structural member, removing said release sheet.

12. The method of Claim 10, including said drying step is accomplished at temperatures of about 100°F to 160°F.

13. The method of Claim 9, including employing ultraviolet curable resin as the material for said curable resin layer; and curing said ultraviolet curable resin layer with ultraviolet radiation from a suitable source.

14. The method of Claim 9, including establishing said curable resin layer in a thickness of about 2 to 7 mils.

15. A method of making a tamper evident element for use on a structural member, said method comprising: providing a backing film; applying a curable resin layer on said backing film; drying said curable resin layer to evaporate the solvents therein; applying a pressure sensitive adhesive layer on said curable resin layer; applying a release sheet on said pressure sensitive adhesive label; and printing indicia on said dried, curable resin layer such that upon curing of said curable resin layer, tampering with said tamper evident element will cause a readily visible, irreversible change in the cured brittle layer.

16. The method of Claim 15, including employing as said structural member a container and employing as said tamper evident element a label.

17. The method of Claim 16, including said drying step is accomplished at temperatures of about 100°F to 160°F.

18. The method of Claim 15, including employing ultraviolet curable resin as the material for said curable resin layer; and curing said ultraviolet curable resin layer with ultraviolet radiation from a suitable source.

19. The method of Claim 15, including establishing said resin layer in a thickness of about 2 to 7 mils.

20. A method of making a tamper evident element for use on a structural member, said method comprising: providing a removable film material having indicia thereon; applying a curable resin layer on said film such that said indicia is absorbed from said film material into said curable resin layer; drying said curable resin layer to evaporate the solvents therein; applying a pressure sensitive adhesive layer on said dried curable resin layer; and removing said film from said curable resin layer, whereby, upon curing of said curable resin layer, tampering with said tamper evident element will cause a readily visible, irreversible change in the cured brittle layer.

21. The method of Claim 20, including employing as said structural member a container and employing as said tamper evident element a label.

22. The method of Claim 21, including applying a release sheet on said pressure sensitive adhesive layer.

23. The method of Claim 22, including said drying step is accomplished at temperatures of about 100°F to 160°F.

24. The method of Claim 20, including employing ultraviolet curable resin as the material for said curable resin layer; and curing said ultraviolet curable resin with ultraviolet radiation from a suitable source.

25. A tamper evident element for use on a structural member, said element comprising: a film having a first surface and a second surface; said first surface having secured thereon a first patch; said second surface having secured thereon a second patch; said second patch defining an area which forms a message; said first patch overlying said second patch so that said message is not visible; and a cured brittle resin layer in overlying contact with said first patch, whereby tampering with said tamper evident element will cause said cured brittle resin layer to fracture and at least in part separate from said film so that at least a portion of said message is visible.

26. The element of Claim 25, wherein said tamper evident element is a label.

27. The element of Claim 25, wherein said first patch has the same color as the portion of the structural member on which said first patch will be disposed.

28. The element of Claim 27, including a layer of pressure sensitive adhesive secured to said second surface.

29. The element of Claim 28, including a release sheet secured to said pressure sensitive adhesive layer.

30. The element of Claim 27, wherein said first patch is printed on said first surface.

31. The element of Claim 30, wherein said second patch is printed on said second surface.

32. The element of Claim 27, wherein said first surface has a plurality of first patches; said second surface has a plurality of second patches; and said cured brittle resin layer in overlying contact with said first patches.

33. The element of Claim 25, wherein said layer is comprised of a resin.

34. The element of Claim 25, wherein said cured brittle resin layer is about 2 to 7 mils thick.

35. A method of making a tamper evident element for use on a structural member, said method comprising: providing a film having a first surface and a second surface; applying a first patch on said first surface; applying a second patch on said second surface, said second patch defining an area which forms a message; and applying a curable resin layer on said first patch, whereby, upon curing of said curable resin layer, tampering with said tamper evident label will cause the cured layer to fracture and at least in part separate from said film so that at least a portion of said message is visible.

36. The method of Claim 35, including employing as said tamper evident element a label.

37. The method of Claim 35, including establishing said first patch having the same color as the portion of said structural member on which said first patch will be disposed.

38. The method of Claim 37, including applying a pressure sensitive adhesive layer on said second surface.

39. The method of Claim 38, including applying a release sheet on said pressure sensitive adhesive layer.

40. The method of Claim 35, including drying said curable resin layer so as to evaporate the solvents therein.

41. The method of Claim 40, including said drying step is accomplished at temperatures of about 100°F to 160°F.

42. The method of Claim 35, including employing ultraviolet curable resin as the material for said curable resin layer; and curing said curable resin layer with ultraviolet radiation from a suitable source.

43. The method of Claim 35, including establishing said resin layer in a thickness of about 2 to 7 mils.

44. A tamper evident structural member comprising: a structural member; and a tamper evident element at least partially covering said structural member disposed adjacent to the exterior of said structural member, said tamper evident element comprising: a film having a first surface and a second surface; said first surface having secured thereon a first patch; said second surface having secured thereon a second patch; a pressure sensitive adhesive layer applied to said second surface for securing said tamper evident element to said structural member; said second patch defining an area which forms a message; said first patch overlying said second patch so that said message is not visible; and a cured brittle resin layer in overlying contact with said first patch, whereby tampering with said tamper evident label or said structural member will cause said cured brittle layer to fracture and at least in part separate from said film so that at least a portion of said message is visible.

45. The member of Claim 44, wherein said structural member is a container and said tamper evident element is a label.

46. The member of Claim 44, wherein said first patch has the same color as the portion of the said structural member on which said first patch will be disposed.

47. The member of Claim 46, wherein said first patch is printed on said first surface.

48. The member of Claim 47, wherein said second patch is printed on said second surface.

49. The package of Claim 44, wherein said cured brittle resin layer is about 2 to 7 mils thick.

50. The package of Claim 45, wherein said container holds products selected from the group consisting of pharmaceutical products, medical instruments and food products.

51. The package of Claim 45, wherein said container is comprised of a blister package having a first layer and a second layer, said first and second layers having a plurality of capsules for retaining individual pharmaceutical products disposed therebetween.

52. A method of providing a structural member having a tamper evident element, said method comprising: providing a structural member; providing a tamper evident element made in accordance with the following method: providing a film having a first surface and a second surface; applying a first patch on said first surface; applying a second patch on said second surface, said second patch defining an area which forms a message; applying a pressure sensitive adhesive layer on said second surface; applying a curable resin layer to said first patch; drying said curable resin layer to evaporate the solvents therein; placing said tamper evident element on said structural member by securing said pressure sensitive adhesive layer thereto; and subsequently curing said curable resin layer, whereby tampering with said tamper evident element or said structural member will cause said curable resin layer to fracture and at least in part separate from said film so that said message is visible.

53. The method of Claim 52, including employing as said structural member a container and employing as said tamper evident element a label.

54. The method of Claim 52, including after applying said pressure sensitive adhesive to said second surface, applying a release sheet on said pressure sensitive adhesive layer; before securing said pressure sensitive adhesive layer on said structural member removing said release sheet; and establishing said first patch having the same color as the portion of said structural member on which said first patch will be disposed.

55. The method of Claim 52, including employing as said curable resin layer an ultraviolet curable resin; and curing said ultraviolet curable resin layer with ultraviolet radiation from a suitable source.

56. The method of Claim 52, including establishing said curable resin layer having a thickness of about 2 to 7 mils.

57. A tamper evident element for use on a structural member comprising: a film having a first surface and a second surface; a cured brittle resin layer applied to at least a portion of said film; and said film having at least one non-bonded region wherein said cured brittle resin layer is not adhesively bonded to said film, whereby tampering with said tamper evident element will cause said cured brittle resin to fracture and at least in part separate from said film, said separation being facilitated by said non-bonded region.

58. The element of Claim 57, wherein said tamper evident element is a label.

59. The element of Claim 57, including a first patch printed on said first surface underlying said non-stick area.

60. The element of Claim 59, wherein said first printed patch is the same color as the portion of the structural member upon which said first patch is disposed.

61. The element of Claim 60, wherein a second patch printed on said second surface completely underlying said first patch; and said second patch defining an area which forms a message, whereby when said cured brittle resin layer separates at least in part from said tamper evident element, said message will become visible.

62. The element of Claim 57, wherein said non-bonded regions are composed of deposits of non-stick material on said first surface.

63. A method of making a tamper evident element for a structural member comprising: providing a film having a first surface and a second surface; applying a curable resin layer on at least a portion of said first surface; and establishing on said first surface at least one non-bonded region wherein said curable resin layer is not adhesively bonded to said film, whereby, upon curing of said curable resin layer, tampering with said tamper evident element will cause said cured brittle resin to fracture and at least in part separate from said film, said separation being facilitated by said non-bonded region.

64. The method of Claim 63, including employing as said tamper evident element a label.

65. The method of Claim 64, including before applying said curable resin layer to said first surface, printing a first patch on said first surface.

66. The method of Claim 65, including providing said first patch in the same color as the portion of said structural member on which said tamper evident element is disposed; printing a second patch on said second surface completely underlying said first patch; and establishing as said second patch an area which forms a message, whereby when said cured brittle resin separates from said structural member said message will become visible.

67. The method of Claim 63, including establishing said non-bonded regions by depositing a non-stick material on said first surface.

68. A tamper evident structural member comprising: a structural member; and a tamper evident element at least partially covering said structural member disposed adjacent to the exterior of said structural member, said tamper evident element comprising: a film having a first surface and a second surface; a cured brittle layer applied to at least a portion of said first surface; a pressure sensitive adhesive layer applied to said second surface for securing said tamper evident element to said structural member; and said first surface having at least one non-bonded region wherein said cured brittle resin layer is not adhesively bonded to said first surface, whereby tampering with said tamper evident label or said structural member will cause said cured brittle resin layer to fracture and at least in part separate from said film, said separation being facilitated by said non-bonded region.

69. The member of Claim 68, wherein said structural member is a container and said tamper evident element is a label.

70. The member of Claim 68, including a first patch printed on said first surface underlying said non-stick area.

71. The member of Claim 68, wherein said first printed patch is the same color as the portion of the structural member upon which said first patch is disposed.

72. The member of Claim 71, wherein a second patch printed on said second surface completely underlying said first patch; and said second patch defines an area which forms a message, whereby when said cured brittle resin layer separates from said structural member, said message will become visible.

73. The member of Claim 68, wherein said non-bonded regions are composed of deposits of non-stick material on said first surface.

74. The member of Claim 69, wherein said container holds products selected from the group consisting of pharmaceutical products, medical instruments and food products.

75. The member of Claim 69, wherein said container is comprised of: a blister package having a first layer and a second layer; and said first and second layers having a plurality of capsules for retaining individual pharmaceutical products disposed therebetween.

76. A method of providing a structural member with a tamper evident element, said method comprising: providing a structural member; providing a tamper evident element made in accordance with the following method: providing a film having a first surface and a second surface; applying a pressure sensitive layer on said second surface; applying a release sheet on said pressure sensitive layer; applying a curable resin layer to at least a portion of said first surface; establishing on said first surface at least one non-bonded region wherein said curable resin layer is not adhesively bonded to said film; drying said curable resin layer so as to evaporate the solvents in said curable resin layer; placing said tamper evident element on said structural member by removing said release sheet and securing said pressure sensitive adhesive layer on said structural member; and subsequently curing said dried curable resin layer, whereby tampering with said tamper evident element or said structural member will cause the cured resin layer to fracture and at least in part separate from said film.

77. The method of Claim 76, including employing as said structural member a container and employing as said tamper evident element a label.

78. The method of Claim 76, including before applying said curable resin layer to said first surface, printing a first patch on said first surface.

79. The method of Claim 76, including providing said first patch in the same color as the portion of said structural member on which said tamper evident element is disposed; printing a second patch on said second surface completely underlying said first patch; and establishing as said second patch an area which forms a message, whereby when said cured brittle resin separates from said structural member, said message will become visible.

80. The method of Claim 76, including establishing said non-bonded resins by depositing a non-stick material on said first surface.