Tamper evident seal for a medical container

A seal formed of laminated films adhered to a peel strip. The seal includes a target area free of adhesive, and adhesive surrounding the target area. The seal is formed so that the target area is visually distinguished from the surrounding adhesive to facilitate placement of the seal on a medical container by a user. The use of a colored adhesive, reflectivity of the adhesive, a colored laminate, or a colored target background can be utilized to make the target area visually different from the surrounding adhesive.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to methods and apparatus for sealing medical containers, and more particularly to techniques that allow a person to accurately align a non-adhesive target area of the seal to a membrane of a medical container.

BACKGROUND OF THE INVENTION

Hospital patients often undergo treatments of many types using intravenous injections of liquids such as antibiotics, vitamins, drugs, narcotics and many other pharmaceuticals. The injection of the liquid is administered into the veins of the patient. As such, it is important that the intravenous process and equipment remain clean and sterile in order to reduce the possibility of allowing bacteria and other undesirable organisms to enter the body of the patient.

Intravenous solutions may include dextrose solutions, sodium chloride and many other solutions. Such solutions can be injected by intravenous means into a patient, and such solutions can be modified to add other treatment liquids, including those noted above. Intravenous (IV) bags are typically delivered to hospitals or pharmacies with the base solutions of dextrose, sodium chloride, etc. The IV bags are generally delivered within individual protective plastic shipping bags to maintain the IV bags in a sterile condition. The hospital assistant or the pharmacist then removes the IV bags containing the IV solution from the protective plastic cover and discards the latter. In a typical day at many hospitals, clinics and pharmacies, several hundred IV bags may be processed so as to have the proper pharmaceutical solution added to the IV solution, as prescribed by the doctors.

The pharmacist, for example, may have delivered to him/her multiple sheets of adhesive labels from the hospital, where each label is preprinted with information which identifies the patient, the size of the IV bag, the medical solutions to be added, the dosages thereof, and other parameters necessary for the proper administration of IV solutions to the correct patient. The preparation of IV bags for the proper modification of medical solutions is conducted in a clean and sterile environment, usually under a laminar air flow hood. The IV bags are removed from the respective protective coverings in the sterile environment. The pharmacist then identifies the drug to be added to the base IV solution in the bag. The drug is drawn into a syringe, or the like, from a bottle and then added to the IV bag by way of the injection port. The injection port of an IV bag includes a spout or portion extending from the bag, with a self-sealing rubber membrane through which the syringe needle is inserted to inject the drug into the IV bag. When the needle is withdrawn, the rubber membrane reseals to maintain the contents of the IV bag sterile.

Once the base IV solution has been modified in the manner desired, an adhesive seal is applied to the injection port of the IV bag. The adhesive seals are generally of a laminated construction, including a foil and one or more layers of a polypropylene material. The type of seals typically applied to injection ports of IV bags and bottles are disclosed in U.S. Pat. No. 4,266,687 by Cummings; U.S. Pat. No. 4,390,104 by Cummings; U.S. Pat. No. 4,423,819 by Cummings; U.S. Pat. No. 4,514,248 by Cummings; U.S. Pat. No. 4,527,703 by Cummings and U.S. Pat. No. 4,598,834 by Singletary. These seals include a target area surrounded by adhesive. The target area is a non-adhesive spot on the seal that contacts the rubber membrane of the injection port. The surrounding area is adhesive covered for adhering to the spout portion of the injection port. Importantly, the seal not only maintains the rubber membrane covered and free from bacteria contamination, but the seal includes slits cut therein so that if attempted to be removed, the seal is torn or otherwise destroyed. Accordingly, any tampering of the seal is readily evident. Lastly, the presence of a seal on the injection port of the IV bag is an indication to the pharmacist that the modification of the contents of the IV bag is complete, and no other processing of the IV bag is required. The presence of the seal on the container thus prevents the accidental injection therein of an additional medication, or a different medication.

In the manufacture of the IV bag seals noted in the above-identified patents, the target area is free from adhesive in that the adhesive at that spot is covered by a paper dot. The seal also includes a pull tab that has a non-adhesive underside, also covered by paper adhered to the adhesive. Thus, the seal is fabricated by covering the entire underside of the laminated foil/poly strip with an adhesive. Paper is then applied to those areas in which it is desired to be non-adherent. Lastly, a silicone-faced peel strip is attached to the adhesive side of the seal. The peel strip is removed from the seal just prior to use by the pharmacist when applying the seal over the injection port of the IV bag.

While the IV bag seals of the prior art have adequately provided their intended functions, they are not as cost effective as could be. Rather, additional manufacturing steps are required in order to make the laminate structure non-adherent at specified areas.

It can be seen from the foregoing that a need exists for a new seal structure for an IV bag or a bottle, where the seal is more economically made and thus cost effective. Another need exists for a new seal that provides additional visual indications of tampering.

SUMMARY OF THE INVENTION

In accordance with the principles and concepts of the invention, there is disclosed a seal, and method of manufacture thereof, for use with medical and other containers.

In accordance with an important feature of the invention, the seal is manufactured in an in-line process using a roll of a laminate material and a roll of peel strip material, screen printing an adhesive in a patterned manner on the peel strip, and then bringing the laminate and the peel strip together under compression to form a long composite strip. A rotary die cutter cuts the laminate and the adhesive to form the individual seals on the peel strip. In accordance with an important feature, the adhesive is screen printed to form areas free from adhesive, which are the target area and the pull tab area of the seal. In accordance with another feature, the adhesive is colored so as to visually define the areas free of adhesive on the seal.

In accordance with another feature of the invention, a seal is disclosed having a laminate body portion and a pull tab portion. The seal is adhered to a peel strip for easy removal thereof when used to seal a container. The body portion has an adhesive free area defining a target area. The pull tab also has an adhesive free area for grasping the same for removal of the seal from the peel strip.

In accordance with another embodiment of the invention, disclosed is a seal for use in providing a protective cover for a container of the type having an opening therein. The seal includes a flexible material of a size for covering the opening of the container; a film of an adhesive material adhering to a side surface of the flexible material except for an area free of the adhesive, the area being surrounded by said adhesive; and a peel strip with one side surface attached to the adhesive, the side surface of the peel strip is formed of a material for allowing release of the adhesive when the flexible material is pulled away from the peel strip.

In accordance with yet another embodiment of the invention, disclosed is a method of fabricating a seal of the type providing a removable protective cover for an opening of a container. The method of fabricating the seal for sealing around the opening of the container includes forming an adhesive area encircling an adhesive free target area of the seal, and attaching a removable peel strip to the adhesive to protect the adhesive free target area from contamination. Further included is the use of an adhesive that does not change color after application of the adhesive to said seal, and forming the seal so that the adhesive free target area is visually distinguished by color from the surrounding adhesive area by a person applying the seal to the container. As a result, when the peel strip is removed, the adhesive free target area is easily visually distinguished from the surrounding adhesive so that the adhesive free target area of the seal can be visually aligned with the container opening and manually applied thereover. The surrounding adhesive portion of the seal can be attached around the container spout, and at least a portion of the seal can be removed from the container to access contents via the opening in the container.

With regard to yet another embodiment of the invention, disclosed is a method of fabricating a seal of the type providing a removable protective cover for a container having a spout with an opening covered by a membrane. The method includes forming a laminate seal structure by adhering a material strip to a peel strip, and adhering the material strip to the peel strip using an adhesive with a colored agent added thereto to achieve a desired color to the adhesive that is visually distinguished from a color of a surface of the material strip to which the colored adhesive is adhered. A colored adhesive is used that does not change color when the seal is removed form the container. The colored adhesive is applied to the laminate seal structure so that the colored adhesive surrounds an adhesive free area on the surface of the material strip and the color of the adhesive visually distinguishes the adhesive free area on the surface of the material strip. An adhesive is used that allows the peel strip to be removed therefrom to expose the colored adhesive surrounding the adhesive free area of the material strip so that a user can visually identify the adhesive free area of the material strip and manually apply the adhesive free area thereof over the membrane of the spout without allowing the colored adhesive to adhere to the membrane of the spout. The user can attach the material strip around the spout of the container using the colored adhesive to adhere the material strip to the spout.

DETAILED DESCRIPTION OF THE INVENTION

With reference toFIGS. 1 and 2, there is shown a strip8of IV bag seals12according to the invention. It should be understood that the seal12is well adapted for sealing medical containers other than IV bags. In any event, the seals12are adhered to a silicone-coated peel or release strip10. When distributed to a pharmacy, hospital, clinic or other user, a strip8of about 1,000 seals are contained within a dispenser box or container, to be described below.

Each seal12is characterized as having a body14with one or more slits, one shown as reference character16. The body portion14of the seal12includes a target area18. The seal12further includes a pull tab20for use in removing the seal12from the peel strip10and handling the same without touching the underlying adhesive-coated area22shown inFIG. 2. The entire bottom surface of the seal12is coated with an adhesive22, except for the target area18and the pull tab20. The target area18is free from adhesive as it is undesirable to allow an adhesive to be placed in contact with the sterile rubber membrane of the IV bag injection port, or the port of a vial. The pull tab20is free from adhesive so that the seal12is easily gripped and removed from the peel strip10. Unlike the prior art seals, the target area18and the pull tab20do not include paper-covered areas. The manner in which the adhesive22is transferred to the seal12is described in more detail below.

The construction of a seal according to one embodiment is shown inFIG. 3. The seal12is constructed of a laminated structure23having a top polypropylene film24, a middle layer of a metal foil26and a bottom film28of polypropylene. The top and bottom polypropylene films24and28can be about six mils thick. The metal foil26can be a silver-colored aluminum metal of about seven mils thickness. Other materials formed of other thicknesses can be used as the laminated structure. Such structures are well known in the art of seals for medical containers. Indeed, the seal12may be constructed of a single layer of material. In order to visually distinguish seals for different uses, a colored film can be applied between the top polypropylene layer24and the metal foil26. Moreover, the top polypropylene layer24can be colored so as to be easily identified. The bottom polypropylene layer28can also be colored.

The laminated structure23is releasably attached to the silicone-coated peel strip10by an adhesive22which, in the preferred embodiment, is colored. The colored adhesive22visually defines the target area18, as shown inFIG. 2. The adhesive22does not adhere to the silicone surface of the peel strip10, but does adhere to the lower surface of the bottom polypropylene film28. As such, when the laminate structure23is pulled from the peel strip10, the adhesive22remains with and becomes part of the seal12. As shown inFIG. 2, the target area18and the bottom side of the pull tab20are free from adhesives.

In use, when the pharmacist needs a seal for sealing a completed IV bag32, the seal12is removed from the peel strip10. The pharmacist then visually locates the target area18, and applies the seal12to the spout30, making sure the target area18is centered over the rubber membrane34. This is shown inFIG. 4. In addition, the pharmacist can wrap or fold the seal12down around the spout30. As noted above, the existence of the seal on the IV bag32conveys the message that the contents of the IV bag32have been altered or modified according to the preprinted label instructions, and the IV bag is ready to be transferred to the hospital or clinic. In the event that the seal12is attempted to be removed from the spout30of the IV bag32, telltale signs of tampering are two fold. First, the seal12will be destroyed as one or more of the slits16will cause tearing of the body14of the seal12. Secondly, portions of the colored adhesive22will remain on the spout30or the IV bag itself32. The residue of the colored adhesive22is readily apparent on clear plastic sidewall of the IV bag. The IV solution is dispensed via the IV port36.

The manufacture of the seal12is described in detail below, and shown schematically inFIG. 5. A long, wide roll40of a silicone-coated peel strip material10, and a long, wide roll42of a laminate material23constitute the starting materials for the in-line process. It should be understood that the laminate structure23of the seal12can be other materials, and can even be a single layer or film of material. The width of both rolls40and42of material is preferably sufficient to make a plurality of seals per unit width of material. In the preferred embodiment, a unit width of material is sufficient to make7-9seals12. The shape of the seals in a unit width may be different from that shown inFIG. 1. The silicone-coated peel strip10undergoes a process where a colored adhesive22is patterned onto the silicone side of the strip10. The adhesive22can be of a hot melt type, a solvent, acrylic or other type suitable for use with screen print equipment. A colored pigment is added to the adhesive22to impart a color thereto. The colored pigment can be in a powder or liquid form, such as a colored ink compatible with the type of adhesive employed. The process includes a screen printer utilizing a mesh roller44having small openings formed in a pattern with the shape shown by the adhesive-coated area22ofFIG. 2. The pattern is repeated around the mesh roller44. Importantly, no adhesive22is deposited in the areas corresponding to the target area18or the pull tab20. In a preferred embodiment, the colored adhesive22is screen printed on the silicone peel strip10, not the laminate structure23of the seal12. Alternatively, the adhesive22can be screen printed on the laminate structure23. The colored adhesive22is forced through small holes in the roller44, whereupon a dot pattern45of a desired thickness of adhesive22is transferred to the peel strip10. The thickness of the colored adhesive is on the order of between about 0.9-1.10 mils, plus or minus 0.1 mil. With such a thin layer of adhesive, the adhesive is used efficiently without compromising the adhering strength of the adhesive material. Because of the thin film of adhesive utilized, the coloring agent added thereto should be substantial so that the thin film of adhesive is visually distinguished from underlying the laminate structure to which it is adhered. Without the use of a coloring agent, it is believed that a raw adhesive material coated as a thin film on a substrate would not be visually distinguished from the underlying substrate. The dot pattern45may be as shown in the enlargement46ofFIG. 5. The adhesive22can be applied in other patterns, such as cross-hatching, etc. The adhesive22used is colored before being applied to the seal12, and does not change color once applied to the seal12. For example, the adhesive22does not change color either when the peel strip10is removed, or when the seal12is removed from the container.

In the process, the adhesive patterned side of the wide peel strip10is brought into contact with the laminate structure23, and pressed together with a pair of spaced-apart rubber nip rollers50aand50b. The nip rollers50aand50bsqueeze the materials10and23together sufficiently to cause the adhesive dot pattern45to be compressed. When compressed, the adhesive22adheres to the surface of the polypropylene layer28. This compression step essentially transfers the adhesive22from the peel strip10to the laminate structure23. After compression, the adhesive dot pattern45is merged together, much like that shown in the enlargement52ofFIG. 2. The diameter of the patterned dots45, as well as the thickness of the adhesive22can be adjusted to achieve the merged pattern ofFIG. 2. The merging of the adhesive dot pattern45is important to prevent any passages or channels between target area18and the environment. The presence of any passages could lead to the migration of bacteria and the like to the target area18and contamination thereof.

The continuous roll material adhered together is coupled to a rotary die cutter station. The rotary die cutter includes a roller54with an engraved cylinder, where the cutting pattern is repeated in all rows around the peripheral surface of the cutting roller54. The rotary die cutter is removable and replaceable with another cutter having different shaped engraved patterns to produce seals with different shapes. It is understood that when using different shaped seals, the adhesive pattern screen would also be different to match the shape of the pattern of the rotary die cutter. In addition to cutting the outer edge of the seal12, the cutter also cuts the tear slits16. The rotary die cutter54is synchronized with the adhesive pattern on the peel strip10so that the outline cut for each seal12corresponds to the outline of the adhesive pattern. Synchronization of the various in-line stations is achieved by the use of gear-driven equipment. The number of engraved areas in a unit width of the rotary die cutter54is a function of the width of the roll material10and23.FIG. 5illustrates that there are four seals cut per unit width. The rotary die cutter54operates in conjunction with a smooth surface roller56. The spacing between the cutting edge of the engraved areas and the surface of the roller56is such that the cuts are made entirely through the laminate structure23, as well as through the layer of adhesive22. The only material that is not cut is the peel strip10.

The waste laminate material and associated adhesive is removed by a processing station, not shown, and wound onto a waste roll and disposed of appropriately. The remaining composite material strip58that proceeds in the processing of the invention is the wide peel strip10with the individual seals12attached thereto. The wide material58is wound onto a roll several thousand feet long. The roll is then placed on a rewinding machine (not shown) that slits the rows apart and winds the product onto a core with the desired number of seals on the roll, such as 1,000 seals per roll. This avoids interrupting the machine each time a roll of 1,000 seals is completed. In the example, the wide strip58is made with four seals across the width of the material strip58, and thus there are three rotary knives to cut the wide strip58into four individual strips, one shown as numeral62. The individual strips62are of a width having only a single seal12, although this is not a necessity. In the event that the user desires to have strips of two or more seals wide, this can be accommodated by configuring the rotary cutter60with the appropriate number of cutting blades.

The individual seal strips62are wound onto individual spools. One spool is shown as numeral64. The spools of seal strips62are placed into respective dispenser boxes or containers, such as would be used by the pharmacist when placing the seals12on the injection ports of IV bags. A clam shell type of plastic container can be used to provide a dispenser box when the roll of seals12is placed therein. The end of the strip of seals can be threaded through an exit opening in the plastic container, and the clam shell halves snap locked together. The individual containers of seals12are next sterilized to remove all bacteria and germs from the product. If a box is used as a container, then the spool of seals can be held in a plastic holder housed within the box to allow rotation of the roll of seals during dispensing. The sterilization of boxed rolls of seals12can be carried out in any conventional manner. In the preferred form, the boxed rolls of seals12are placed in a vented plastic bag and placed in a sterilization chamber. A sterilizing agent, such as ethylene oxide gas, is injected into the chamber at a specified temperature, pressure and humidity, for a specified time to destroy all bacteria. This type of sterilizing gas permeates through the various materials of the seal12and is effective to sterilize the target area18. The sterilizing gas is then removed from the chamber. The boxes remain in the bags and are made ready for shipment to the users of the seals12.

FIG. 6illustrates another embodiment of the invention well suited for use with bottle containers holding medical drugs and the like. Bottles of this type have a rubber membrane held within the opening of the bottle by a metal rim. The seal70has a round body72with a round target area74free of adhesive. The round body72of the seal70is well adapted for attachment to the rim over the rubber membrane. The bottom side of the seal body72is coated in a dot pattern of a colored adhesive in the manner described above. The body72of the seal70can be adhered to the metal rim and/or to the neck of the bottle. A pull tab76includes on a bottom surface an adhesive free area78for allowing a user to easily grasp the seal70and remove it from the peel strip82. One or more slits80are provided for allowing the body72of the seal to be easily torn should it be attempted to be removed from the bottle. The seal70can be made in the same manner described above, except with a different pattern for the adhesive dispensing screen44, and a different shape engraved cylinder on the rotary die cutter54.

FIG. 7illustrates a shape of yet another seal86constructed according to the concepts of the invention described above. The shape of this seal86is readily adapted for use with an IV bag having a side injection port. The multiple ears88can be folded to conform around the side injection port.

In accordance with another embodiment,FIG. 8illustrates a seal90constructed so that there is a prominent visual distinction between the adhesive-covered areas and the adhesive-free areas. The cross-hatched area92depicts an area of the seal that is colored, whereas the areas94and96that are not cross-hatched depict areas of the seal90that are not colored. The area94represents the target area of the seal90, and the area96represents the pull tab for grasping to remove the peel strip, not shown. The coloring of the pull tab96area is optional. According to this embodiment, the metal foil portion of the seal90is fabricated to impart a color to only the cross-hatched areas92, and leave the other areas94and96free of the color. In other words, the areas94and96will remain a neutral aluminum foil color, such as a shiny silver color having a chrome-like appearance. The cross-hatched area92can be colored any brilliant color, such as green, red, blue, yellow, purple, orange, etc.

During processing of the components of the seal90, one side of the metal foil can be passed by a color agent dispenser to color selected areas of the metal foil. An ink, stain, paint or other color agent can be applied to the cross-hatched area92, and leave the other areas94and96free of the color agent. Techniques exist where a liquid color agent can be jetted onto the side of the metal foil at selected areas. As such, the liquid color agent can be jetted as a large number of high density dots onto the metal foil in the area92. As an alternative, the color-free areas96and94can be masked with respective adhesive patches applied to the metal foil, and a color agent sprayed onto the entire side of the metal foil. Then, the adhesive patches can be removed to expose the color-free areas94and96of the foil material. Another method of coloring the surface of the metal foil is to screen print a colored agent onto the foil surface, where the screen is patterned to only allow the color agent to be applied to the cross-hatched area92. An ink, dye or paint can be used as the color agent during the screen printing process.

A roll of the metal foil can be processed to apply the color agent in a patterned manner to the one side of the foil material. This can be carried out prior to the lamination of the same to other materials, such as one or more layers of polypropylene. The colored metal foil can then be rolled back up into a roll and used for subsequent processing to form the complete seal, as described above. The roll of the color-patterned seals can then be used during the normal lamination process where the peel strip is adhered to the metal foil to from the composite seal90. The adhesive can be applied as a thin film, and thus is very transparent to thereby allow the colored surface thereunder to be easily seen. It is well within the skill of those in the art to time or otherwise control the movement of the roll of the colored metal foil so that an adhesive is applied only to the colored areas92of the metal foil, and not applied to the color-free areas94and96. As noted above, the patterned adhesive can be applied to the peel strip, and then the peel strip registered with the metal foil and pressed onto it to adhere the layers together until the peel strip is removed by the user of the seal. The adhesive can also be applied in a patterned manner directly to the colored surface92of the metal foil, and then the peel strip pressed onto the adhesive. The cutting of the laminate structure to the desired shape can be carried out in the manner described above.

It can be appreciated that the color-free areas94and96, and especially the target area94, are visually distinguishable to a great extent from the surrounding colored area92. This allows a user of the seal90to easily align the target area with the spout of a container or vial and apply the same thereto without allowing the adhesive covered areas to touch the spout membrane. As noted above, this is important when applying a seal to a medical container and preventing the adhesive from being transferred to the membrane of the container spout.

FIG. 9illustrates another embodiment of the metal foil layer of a seal98, where the color agent is applied only to the target area100, and not to the remainder of the metal foil layer. Similar processing can be carried out in the manner described above, but instead applying the color agent only to the target area100. Again, the seal98of this embodiment has a target area100that is highly distinguishable from the color-free areas102, to thereby facilitate alignment of the seal98when applying the same to a container.

In either of the embodiments ofFIGS. 8 and 9described above, it is easy to form selected areas of the seal90or98with a highly colored appearance to more easily distinguish the target area of the seal from the surrounding area. The deep coloring of the metal foil is much easier to achieve than forming a very thin layer of colored adhesive so that the color thereof is deep and easily distinguishable from the non-adhesive areas. However, those skilled in the art may find it advantageous to use both a colored metal foil (patterned or not) as well as a colored adhesive. The color agent added to the adhesive can be micron-size particles, or other suitable size particles, mixed with the adhesive to provide a visual distinction with the surrounding non-adhesive areas. The particles can be silver colored to provide a reflectivity to the adhesive that is otherwise not a characteristic of the adhesive. To that end, the reflective or colored particles can be mixed so that the density thereof is substantially high in the adhesive to provide a highly reflective surface for the adhesive.

In order to provide a visual distinction between the target area of the seal, as compared to the surrounding areas, the surface of the metal foil can be altered to change the reflectivity thereof. For example, when using a metal foil having a shiny silver surface, the surface of the foil forming the target area can be altered or spoiled to change the reflectivity thereof.

FIGS. 10aand10billustrate a seal104constructed according to another embodiment. Here, the reflective properties of the adhesive of the seal104are used to distinguish the target area106and the pull tab110from the surrounding adhesive-covered area108. The adhesive used in this embodiment can be modified to alter the normal properties thereto for increasing the reflectivity thereof. There are currently available adhesives that exhibit unique reflective properties. Such adhesives are available from 3M, including reflective inks that can be added to adhesives. When using an adhesive with reflective properties, the adhesive-covered area can be visually distinguished from the target area. The use of a reflective adhesive can also be used in combination with a target area that has a reduced reflective characteristic. The reflectivity of the target area can be reduced by spoiling the smooth and shiny surface thereof. The reflectivity of the target area can be spoiled by slightly etching the area to reduce the shiny characteristic. The reflectivity of the target area can also be spoiled by using a dull or flat paint, ink or other liquid that can be selectively applied to the target area of the seal. Many other methods can be used to reduce the reflectivity of the target area.

With regard toFIG. 10b, there is illustrated a sectional view of the seal104ofFIG. 10a. The top of the seal104illustrates the adhesive layer. The bottom of the seal104illustrates the laminated structure which includes a metal film and one or more layers of polypropylene. When utilizing an adhesive with reflective properties, the light112striking the side of the seal104, as shown, is reflected114off of the adhesive108and can be seen by the user attempting to apply the same to the spout of a container, or vial port. The reflections112of the light rays appear shiny to the observer. It can be seen that the light rays116striking the target area106are not reflected, or at least are reflected with reduced intensity. As such, the user of the seal104can more easily distinguish the target area106from the surrounding adhesive area108and more easily apply the same to a container.

As an alternative to the modification of the reflective properties of the adhesive, other visual characteristics can be considered when choosing an adhesive. For example, adhesives that are responsive to certain wavelengths of light can be used. An adhesive that absorbs certain wavelengths of light, while the target area does not, can be used as a mechanism to provide visual distinction between the areas.

From the foregoing, disclosed is a seal, and method of manufacture thereof, which overcomes many of the shortcomings of the seals made according to the prior art. The seal according to the invention does not require paper to provide adhesive-free areas. Rather, the seal of the invention initially deposits the adhesive in a pattern so that there is no adhesive where none is desired. In addition, in the process of making the seal of the invention, the adhesive is applied to the peel strip, and then transferred to the laminate seal structure. The adhesive can be colored to provide a telltale indication of removal of the seal from a container. In addition, the colored adhesive is advantageous in visually defining the target area of the seal. These and other features will be apparent from the foregoing description of the invention.

While the preferred and other embodiments of the invention have been disclosed with reference to a specific seal and method of manufacture thereof, it is to be understood that many changes in detail may be made as a matter of engineering choices without departing from the spirit and scope of the invention, as defined by the appended claims.