GB2388812A

GB2388812A - Tamper seal for a packaging product

Info

Publication number: GB2388812A
Application number: GB0208430A
Authority: GB
Inventors: Jonathan Lee Round
Original assignee: MET TECHNOLOGY Ltd DE
Current assignee: MET TECHNOLOGY Ltd DE
Priority date: 2002-04-12
Filing date: 2002-04-12
Publication date: 2003-11-26
Anticipated expiration: 2022-04-12
Also published as: GB2388812B; GB0208430D0

Abstract

A packaging product 2 including a tamper seal, the tamper seal comprising a substrate layer 24, surface indicia 26 attached to a portion of the substrate layer 24, the surface indicia 26 having an acid resistant coating 28 on the surface opposite the surface attached to the substrate layer 24, a substantially opaque layer 30 attached to and covering the substrate layer 24 including the surface indicia 26, an adhesive coating 8 on at least the portion of the opaque layer 30 coating the surface indicia 26 and a sealing strip 9 adhered to the adhesive coating 8, wherein the strength of the attachment of the adhesive coating 8 to the opaque layer 30 and the sealing strip 9 is greater than the strength of the attachment of the opaque layer 30 to the acid resistant coating 28 and/or the acid resistant coating 28 to the surface indicia 26 so that removal of the sealing strip 9 removes the opaque layer 30 from the acid resistant coating 28 and or the acid resistant coating 28 from the surface indicia 26 revealing the said surface indicia 26.

Description

23888 1 2

A TAMPER SEAL

The present invention relates to a tamper seal and, in particular, but not exclusively, a tamper seal which 5 displays characters after the tamper seal is broken. The invention also incorporates a process for producing a tamper sealed product.

Tamper sealed products are now commonplace in many lo industries. Generally products may require a seal to retain freshness or security. In such cases, it is important for both the manufacturers and the public who are purchasing products to be assured that the product has not been compromised down the supply chain.

In addition, it may be desirable to display other Information after the seal has been broken. For instance, it may be desirable to display safety warnings, advertising or technical data upon removal of the seal.

20 Prior art tamper seals tend to include a mechanical

feature which remains intact until the seal is broken. As such, they are limited in the information they provide and only serve the purpose of indicating whether the seal has been removed.

According to a first aspect of the present invention, there is provided a packaging product including a tamper seal, the tamper seal comprising a substrate layer, surface indicia attached to a portion of the substrate layer, the surface indicia having an acid resistant coating on the surface opposite the surface attached to the substrate layer, a substantially opaque layer attached to and covering the substrate layer including the surface

indicia, an adhesive coating on at least the portion of the opaque layer coating the surface indicia and a sealing strip adhered to the adhesive coating, wherein the strength of the attachment of the adhesive coating to the 5 opaque layer and the sealing strip is greater than the strength of the attachment of the opaque layer to the acid resistant coating and/or the acid resistant coating to the surface indicia so that removal of the sealing strip removes the opaque layer from the acid resistant coating 10 and or the acid resistant coating from the surface indicia revealing the said surface indicia.

Preferably, the acid resistant coating is transparent.

15 Preferably, the surface indicia are formed by a metallised film and, accordingly, preferably have a metallic colour.

Advantageously, a metallic colour will be visible on both a transparent and opaque non-metallic background.

20 Preferably, the substrate layer is transparent.

Preferably, the opaque layer is in the form of coloured ink. 25 Preferably, the sealing strips and substrate layers are formed from suitable packaging films.

Advantageously, the tamper seal can take advantage of existing demetalLisation technology. Metallised film is 30 printed in the art by taking a laminate film having a metallic surface layer and printing the desired indicia on the metallic surface of the layer using a transparent acid resistant lacquer. The film is then subjected to an acid

( 3 treatment step which removes all the metallic surface material from the laminate substrate layer apart from the areas which are protected by the lacquer. The metallic indicts are then left printed on the substrate layer.

5 Although the acid resistant lacquer protects the underlying metallic surface from acid attack during demetallisation, surprisingly, it does not provide a particularly strong bond with ink and this differential adhesive property may be utilised in a tamper seal.

1 to Therefore, according to a second aspect of the present invention there is provided a method of producing a tamper seal for a package comprising the steps of: (a) printing incidia on a metallised packaging sheet -.5 using an acid resistant coating; (b) removing metallised film from non-printed sheet by acid treatment to leave indicia and at least a substrate layer; (c) attaching an opaque film to the indicia and the 2 substrate layer; (d) applying an adhesive to the opaque film on at least the areas coating the printed indicia; (e) attaching a sealing strip to the adhesive to provide the seal of the package.

The metallised packaging sheet is of the type typically comprising a laminate of at least a polymeric substrate film and a metallic surface film. Typical substrates for any aspect of the present invention may be selected from 30 one or more of, polypropylene, for instance, orientated polypropylene, polyethylene, polyvinylchloride, polyallomer, polybutylene, polycarbonate, polyester, polyethylene terephthalate, polyimides, poly-4

( 4 methylpentene-1, polyethylene oxides, polystyrene, I polytetrafluoroethylene, polymethyl ether, polyvinylidene chloride and polyvinyl pyrrolidone; and suitable copolymers thereof. I The metallic surface may be any suitable metal such as aluminium. Typically, the indicia are in the form of a message such 1() as a warning, technical information or advertising.

The seal may work more effectively when the printed area is in the form of a line of text as this simplifies the application of adhesive via a straight strip to which is 15 applied a sealing strip for the package. However, the invention is not limited to printed lines of indicia and the printed area may take any suitable design configuration which could be utilized to seal the package.

For instance, the indicia could form a circular, curved or i" angular configuration.

Advantageously, when the sealing strip is pulled away from the opaque film, the adhesive pulls the film away from the underlying acid resistant coating and/or the acid resistant coating from the metallic indicia due to the greater adhesion between the opaque film and the adhesive and the sealing strip and the adhesive.

Preferably, the adhesive is a hot-melt adhesive known in 30 the polymer bag sealing art, particularly, hot-melt adhesives for polypropylene or polyethylene film or sheet.

According to a third aspect of the present invention there is provided a method of producing a tamper seal for a package comprising the steps of: 5 - providing surface indicia on at least a portion of a substrate layer the surface indicia each having a release coating covering the surface opposite the surface attached to the substrate layer 1: - attaching a substantially opaque surface coating to the substrate layer including the release coated surface indicia - attaching an adhesive to the said opaque surface on at least the area(s) coating the surface indicia and lo-. attaching a sealing strip to the adhesive, wherein the strength of attachment of the sealing strip and the opaque surface to the adhesive is greater than the strength of attachment of the release coating to the TIC surface indicia and/or the release coating to the opaque coating. Preferably, the opaque coating is a suitable ink. The ink may be selected so as to have a low affinity with the 25 release coating.

According to a fourth aspect of the present invention there is provided a tamper seal for a packaging product comprising a substrate layer, surface indicia attached to 30 at least a portion of the substrate layer, the surface indicia having a release coating on the surface opposite the surface attached to the substrate layer, a

substantially opaque layer attached to and covering the substrate layer including the release coated surface indicia, an adhesive coating on at least the portion of the surface of the opaque layer coating the surface 5 indicia, and a sealing strip adhered to the adhesive coating, wherein the strength of attachment of the sealing strip and opaque surface to the adhesive is greater than the strength of attachment of the release coating to the surface indicia and/or the release coating to the opaque lo coating.

Preferably, the sealing strip forms part of a larger sheet which overlaps the adhesive layer so that the non adhered overlapping portion of the sheet may be conveniently held 15 by the user during the step of peeling the strip away from the adhesive layer.

The packaging product may be in the form of bags, boxes, bottles or other types of containers.

The invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a tamper seal for a packaging bag; 5 Figure 2 shows a schematic cross-section through a tamper sealed package along line A-A' of figure 1; Figure 3 shows a schematic cross-section along line B-B' of figure 1; Figure 4 shows the package of figure 1 after the sealing : strip has been peeled back; and Figure 5 shows a crosssection along line A-A' of figure 4.

Referring to figure 1 the front face 4 of a sealed package 2 has a closure flap 6 of a Holdover construction common in the art. The closure flap 6 is sealed to the front face 4 of the package 2 by means of a strip of adhesive 5 material 8 to which the undersurface 10 of the sealing strip portion 9 of the above flap 6 is adhered. The adhesive strip 8 extends between the parallel edges 12, 14 of the front face 4 of the package 2 in parallel alignment with the upper and lower edges 16, 18. Apart 3 from the sealing strip section 9 of the flap 6 which adheres to the adhesive strip 8, the rest of the flap is merely folded so that it rests on top of the front face 4 of the package. Accordingly, in use, either of the bottom corners 20, 22 of the foldover flap 6 may be folded back l- to provide a means of purchase to peel back the sealing strip 9 from the adhesive strip 8. The flap 6 is made from a transparent material whereas the front face of the package 2 has its whole surface coated with a black ink. Accordingly, the adhesive strip 8 adheres to the 0 underlying black ink layer along the length of the strip 8. Referring to figure 2, a cross section along line A-A' shows a schematic view through the foldover flap 6 and the Front face 4 of the package 2. The face 4 of the package comprises a transparent substrate film sheet 24 and a 25 series of spaced indicia 26a, b, c, d, e, f attached to the upper surface of the substrate layer 4 at spaced intervals. Each indicia is coated on the surface opposite the surface attached to the substrate layer with a release coating 28a, b, c, d, e, f. An ink coating layer 30 is 30 attached to the same substrate surface to which the indlcia are attached and also coats the indicia including the release coating thereof.

( 8 The indicia are made from a metallic coating material designed to adhere to the surface of the substrate 24 and the release coating material is made from an acid resistant lacquer designed to withstand an acidic 5 demetallisation process and thereby protect the metallic layer located thereunder. The adhesive layer 8 is coated on the ink layer 30 and the foldover flap 6 is sealed to adhesive layer 8 along the sealing strip section 9. Along the surface of the adhesive layer 8 opposite the surface 10 adhered to the ink layer 30.

Referring to figure 4, the corner 22 of the foldover flap 6 has been peeled back along the sealing section 9 to reveal the word SEAL printed in metallic colour and 15 located beneath the ink coating layer 30. Due to the greater strength of the adhesive bond between the adhesive 8 and the ink 30 compared with the strength of the bond between the ink layer 30 and the upper surface of the release coating 28, the ink coating located immediately ?(J above the surface of the release coating 28 has come away with the adhesive material on the under surface of the strip 9. The effect on the ink coating layer is more vividly shown with reference to figure 5 which is a schematic sectional view along line A-A' of figure 4. The 25 metallic 1ndicia 26 remains attached to the substrate layer 24 and the release coating 28 remains located on the surface of the metallic indicia opposite the surface attached to the substrate layer. However, the portion of the ink layer attached to the surface of the release 3C coating opposite the surface attached to the metallic indicia has been pulled away from the surface of the release coating leaving a series of windows 42a, b and c, which correspond to the shapes of the indicia. The

release coating is made from a transparent material typically an acid resistant lacquer so that the metallic ind-cia become visible from the surface after the sealing section 9 of the flap 6 has been peeled off the adhesive 5 strip 8.

By way of example, a method of preparation of the tamper seal will now be more particularly described. A metallised film material comprising an orientated 10 polypropylene substrate and aluminium film layer coated over the polymer substrate is printed on the metallic surface with desired indicia using an acid resistant lacquer (De-met Lacquer available from Seca Chemicals Ltd). The lacquer is transparent so that at this stage l5 the indicia are not visible. The lacquer printed film is then subjected to a demetallisation process using an acid removal technique known in the art to remove the aluminium layer from the polypropylene substrate layer. The process effectively removes all the metallised layer except the 2Cj lacquer printed areas so that the net result of the process leaves the printed area appearing as metallic indicia on a transparent polymer substrate.

At this stage, the surface of the polymer substrate including the release coated metallic coloured indicia are printed with a black ink suitable for polypropylene (Black OR Ink from Seca Chemicals Ltd with a suitable propanol solvent) so that the indicia are no longer visible. The adhesive hot-melt strip may then be located across the ink 3r surface on top of the printed area which it is desired to reveal after the package has been unsealed. Finally, a transparent polypropylene sealing strip is layered on top of the adhesive strip to provide a package seal. The

( 10 sealing strip may form a portion of a foldover flap of the package. Subsequently, when the sealing strip is peeled away from the substrate, the ink located above the metallic characters is removed together with the sealing strip to reveal the metallic indicia desired.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and

which are open to public inspection with this specification, and the contents of all such papers and

documents are incorporated herein by reference.

l5 All of the features disclosed in this specification

(including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, :0 except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including

any accompanying claims, abstract and drawings), may be 25 replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features

( disclosed in this specification (including any

accompanying claims, abstract and drawings), or to any cove] one, or any novel combination, of the steps of any method or process so disclosed.

r

Claims

1. A packaging product including a tamper seal, the tamper seal comprising a substrate layer, surface 5 indicia attached to a portion of the substrate layer, the surface indicia having an acid resistant coating on the surface opposite the surface attached to the substrate layer, a substantially opaque layer attached to and covering the substrate 10 layer including the surface indicia, an adhesive coating on at least the portion of the opaque layer coating the surface indicia and a sealing strip adhered to the adhesive coating, wherein the strength of the attachment of the adhesive coating 15 to the opaque layer and the sealing strip is greater than the strength of the attachment of the opaque layer to the acid resistant coating and/or the acid resistant coating to the surface indicia so that removal of the sealing strip removes the 20 opaque layer from the acid resistant coating and or the acid resistant coating from the surface indicia revealing the said surface indicia.

2. A tamper seal for a packaging product comprising a substrate layer, surface indicia attached to at 25 least a portion of the substrate layer, the surface indicia having a release coating on the surface opposite the surface attached to the substrate layer, a substantially opaque layer attached to and covering the substrate layer including the release 30 coated surface indicia, an adhesive coating on at least the portion of the surface of the opaque layer coating the surface indicia, and a sealing strip adhered to the adhesive coating, wherein the

strength of attachment of the sealing strip and opaque surface to the adhesive is greater than the strength of attachment of the release coating to the surface indicia and/or the release coating to 5 the opaque coating.

3. A tamper seal as claimed in claim 2, wherein the release coating is an acid resistant coating.

4. A packaging product or tamper seal as claimed in any preceding claim, wherein the acid resistant lo coating is transparent.

5. A packaging product or tamper seal as claimed in any preceding claim, wherein the sealing strip forms part of a larger sheet which overlaps the adhesive layer.

15 6. A packaging product or tamper seal as claimed in any preceding claim, wherein the packaging product may be in the form of bags, boxes, bottles or other types of containers 7. A packaging product or tamper seal as claimed in 20 any preceding claim, wherein the surface indicia are formed with a metallised film.

8. A packaging product or tamper seal as claimed in any preceding claim, wherein the surface indicia have a metallic colour.

25 9. A packaging product or tamper seal as claimed in any preceding claim, wherein the substrate layer is transparent. lo. A packaging product or tamper seal as claimed in any preceding claim, wherein the opaque layer is in 30 the form of coloured ink.

11. A packaging product or tamper seal as claimed in any preceding claim, wherein the ink is selected so as to have a low affinity with the release coating.

( 2. A packaging product or tamper seal as claimed in any preceding claim, wherein the sealing strips and substrate layers are formed from suitable packaging films. 5 13. A packaging product or tamper seal as claimed in any preceding claim, wherein the substrate layer comprises a metallised packaging sheet being a laminate of at least a polymeric substrate film and a metallic surface film.

lo 14. A packaging product or tamper seal as claimed in claim 13, wherein the substrate film is selected from one or more of, polypropylene, for instance, orientated polypropylene, polyethylene, polyvinylchloride, polyallomer, polybutylene, 5 polycarbonate, polyester, polyethylene terephthalate, polyimides, poly-4-methylpentene-1, polyethylene oxides, polystyrene, polytetrafluoroethylene, polymethyl ether, polyvinylidene chloride and polyvinyl pyrrolidone; 20 and suitable copolymers thereof.

15. A packaging product or tamper seal as claimed in either claim 13 or claim 14, wherein the metallic surface is aluminium.

16. A packaging product or tamper seal as claimed in s any preceding claim, wherein the indicia are in the form of a message such as a warning, technical information or advertising.

7. A packaging product or tamper seal as claimed in any preceding claim, wherein the indicia are in the 30 form of a line of text.

18. A packaging product or tamper seal as claimed in any preceding claim, wherein the adhesive coating is a hot-melt adhesive.

f A packaging product or tamper seal as claimed in claim 18, wherein the hot-melt adhesive is for polypropylene or polyethylene film or sheet.

20. A method of producing a tamper seal for a package 5 comprising the steps of: (a) printing incidia on a metallised packaging sheet using an acid resistant coating; (b) removing metallised film from non-printed sheet by acid treatment to leave indicia and lo at least a substrate layer; (c) attaching an opaque film to the indicia and the substrate layer; (d) applying an adhesive to the opaque film on at least the areas coating the printed indicia; 5 (e) attaching a sealing strip to the adhesive to provide the seal of the package.

21. A method of producing a tamper seal for a package comprising the steps of: (a) providing surface indicia on at least a 20 portion of a substrate layer (b) the surface indicia each having a release coating covering the surface opposite the surface attached to the substrate layer (c) attaching a substantially opaque surface 25 coating to the substrate layer including the release coated surface indicia (d) attaching an adhesive to the said opaque surface on at least the area(s) coating the surface indicia and 30 (e) attaching a sealing strip to the adhesive, wherein the strength of attachment of the sealing strip and the opaque surface to the adhesive is greater than the strength of attachment of the

release coating to the surface indicia and/or the release coating to the opaque coating.

22. A method as claimed in claim 20, wherein the opaque film comprises an opaque coating.

5 23. A method as claimed in claim 21 wherein the substrate layer comprises a metallised packaging sheet. 24. A method as claimed in claim 21, wherein the release coating is an acid resistant coating.

lo 25. A method as claimed in any of claims 20 to 24, wherein the acid resistant coating is transparent.

26. A method as claimed in any of claims 20 to 25, wherein the sealing strip forms part of a larger sheet which overlaps the adhesive layer.

5 27. A method as claimed in any of claims 20 to 26, wherein the package may be in the form of bags, boxes, bottles or other types of containers.

28. A method as claimed in any of claims 20 to 27, wherein the surface indicia are formed with a 20 metallised film.

23. A method as claimed in any of claims 20 to 28, wherein the surface indicia have a metallic colour.

30. A method as claimed in any of claims 20 to 29, wherein the substrate layer is transparent.

25 31. A method as claimed in any of claims 20 to 30, wherein the opaque coating is a suitable ink.

32. A method as claimed in any of claims 20 to 31, wherein the ink is selected so as to have a low affinity with the release coating.

30 33. A method as claimed in any of claims 20 to 32, wherein the sealing strips and substrate layers are formed from suitable packaging films.

34. A method as claimed in any of claims 20 to 33, wherein the metallised packaging sheet comprises a laminate of at least a polymeric substrate film and a metallic surface film.

5 35. A method as claimed in claim 34, wherein the polymeric substrate is selected from one or more of, polypropylene, for instance, orientated polypropylene, polyethylene, polyvinylchloride, polyallomer, polybutylene, polyearbonate, o polyester, polyethylene terephthalate, polyimides, poly4-methylpentene-1, polyethylene oxides, polystyrene, polytetrafluoroethylene, polymethyl ether, polyvinylidene chloride and polyvinyl pyrrolidone; and suitable copolymers thereof.

6. A method as claimed in either of claim 34 or claim 35, wherein the metallic surface is aluminium.

37. A method as claimed in any of claims 20 to 36, wherein the indicia are in the form of a message such as a warning, technical information or 20 advertising. 38. A method as claimed in any of claims 20 to 37, wherein the indicia are in the form of a line of text. 39 A method as claimed in any of claims 20 to 38, 25 wherein the adhesive is a hot-melt adhesive.

40. A method as claimed in claim 39, wherein hot-melt adhesive is for polypropylene or polyethylene film or sheet.

41. A packaging product substantially as hereinbefore 30 described and with reference to the accompanying illustrations.

42. A tamper seal substantially as hereinbefore described and with reference to the accompanying illustrations. 43. A method substantially as hereinbefore described 5 and with reference to the accompanying illustrations.