Tampa-indicating article for reusable substrates

• US 6,372,341 B1
• Filed: 04/27/1998
• Issued: 04/16/2002
• Est. Priority Date: 04/27/1998
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Ludwig, Pauline E., Jung, Dieter
• Primary Examiner(s): Zirker, Daniel
• Application Number:
  US09/067,250
• Time in Patent Office: 1,450 Days
• Field of Search: 428/354, 428/355.RA, 428/915, 428/916
• US Class Current: 428/354
• CPC Class Codes: C09J 2301/302 the adhesive being pressure-sensitive, i.e. tacky at temperatures inferior to 30°C
• CPC Class Codes: G09F 3/0292 tamper indicating labels
• CPC Class Codes: Y10S 428/915 Fraud or tamper detecting
• CPC Class Codes: Y10S 428/916 Fraud or tamper detecting
• CPC Class Codes: Y10T 428/2848 Three or more layers

Abstract

A tamper-indicating article comprises (a) a pressure-sensitive adhesive film or pressure-sensitive adhesive-coated tape that can be removed, without exhibiting cohesive failure, from a substrate surface (e.g., an automobile windshield) by stretching the film or tape; and (b) at least one damageable layer that shows cohesive or intralayer failure when an attempt is made to remove the article from the substrate surface. The article is especially useful for application to valuable, non-disposable substrates and can be removed therefrom without substrate damage.

Claims

1. A tamper-indicating article comprising (a) a film of pressure-sensitive adhesive or a pressure-sensitive adhesive-coated tape that can be removed from a substrate surface, without exhibiting cohesive failure, by stretching said film or said tape;

and (b) at least one damageable layer that exhibits cohesive failure when an attempt is made to peel said article from said substrate surface;

wherein said attempt to peel said article from said substrate surface also results in the separation of said components (a) and (b), with said component (a) remaining bonded to said substrate surface.

3. The article of claim 1 wherein said film or said tape can be removed from said substrate surface by stretching said film or said tape at an angle of about 45 degrees to said substrate surface.

4. The article of claim 1 wherein component (a) is a pressure-sensitive adhesive-coated tape.

5. The article of claim 1 wherein said film or said tape comprises a pressure-sensitive adhesive selected from the group consisting of acrylic, block copolymer, rubber resin, poly(alpha olefin), and silicone pressure-sensitive adhesives.

6. The article of claim 5 wherein said pressure-sensitive adhesive is selected from the group consisting of acrylic pressure-sensitive adhesives and silicone pressure-sensitive adhesives.

7. The article of claim 1 wherein said tape comprises a carrier to the selected from the group consisting of films of silicone polymers;

films of polyurethanes;

films of polymers comprising polymerized units derived from one or more olefin monomers, from one or more acrylic monomers, from one or more vinyl monomers, and from mixtures thereof; and

films of blends of said polymers.

8. The article of claim 7 wherein said polymers are selected from the group consisting of polyolefins and block copolymers.

9. The article of claim 1 wherein said tape comprises (a) a carrier having a lengthwise elongation at break of from about 50 to about 1200 percent, a Young'"'"'s modulus of at least about 2500 psi (17.2 N/mm²), but less than about 72,500 psi (500 N/mm²), and a tensile strength at break that is sufficiently high that said carrier does not rupture during peeling of said tape from said substrate surface;

and (b) a pressure-sensitive adhesive on at least a portion of at least one major surface of said carrier;

said tape being capable of being firmly bonded to said substrate surface and further capable of being removed therefrom by being stretched at an angle of about 45 degrees to said substrate surface.

10. The article of claim 9 wherein said carrier has less than about 50 percent elastic recovery after stretching.

11. The article of claim 1 wherein said damageable layer exhibits said cohesive failure by being at least partially destroyed or irreversibly deformed.

12. The article of claim 1 wherein said damageable layer is selected from the group consisting of frangible materials, papers, indicia, hot-melt adhesives, pressure-sensitive adhesives, and irreversibly deformable polymeric films.

13. The article of claim 1 wherein said damageable layer comprises indicia.

14. The article of claim 1 wherein said damageable layer comprises holographic film.

15. The article of claim 1 further comprising a patterned release coating.

16. The article of claim 1 further comprising a primer coating.

17. The article of claim 1 further comprising a retroreflective layer.

26. A substrate bearing the article of claim 1.

2. A tamper-indicating article comprising (a) a pressure-sensitive adhesive film or pressure-sensitive adhesive-coated tape that can be cleanly removed from a substrate surface, without exhibiting cohesive failure, by stretching said film or said tape;

and (b) at least one damageable layer;

wherein the cohesive strength of said damageable layer is less than the adhesive strength between said substrate surface and said film or said tape, and said adhesive strength is less than the cohesive strength of said film or said tape; and

wherein an attempt to peel said article from said substrate surface results in the separation of said components (a) and (b), with said component (a) remaining bonded to said substrate surface.

18. A tamper-indicating article comprising (a) a pressure-sensitive adhesive-coated tape comprising (i) a carrier having first and second major surfaces and having a lengthwise elongation at break of from about 50 to about 1200 percent, a Young'"'"'s modulus of at least about 2500 psi (17.2 N/mm²), but less than about 72,500 psi (500 N/mm²), and a tensile strength at break that is sufficiently high that said carrier does not rupture during peeling of said tape from a substrate surface;

and (ii) pressure-sensitive adhesive on at least a portion of said first and second major surfaces of said carrier;

said tape being capable of being firmly bonded to said substrate surface and further capable of being removed therefrom by being stretched at an angle of about 45 degrees to said substrate surface;

(b) a damageable layer that exhibits cohesive failure when an attempt is made to peel said article from said substrate surface, said damageable layer comprising indicia;

(c) a patterned release coating; and

(d) a retroreflective layer;

wherein said attempt to peel said article from said substrate surface also results in the separation of said components (a) and (b), with said component (a) remaining bonded to said substrate surface.

19. The article of claim 18 wherein said carrier has less than about 50 percent elastic recovery after stretching.

20. The article of claim 18 wherein said tape is capable of being removed from said substrate surface by being stretched in a direction substantially parallel to said substrate surface.

21. The article of claim 18 wherein said pressure-sensitive adhesive comprises acrylic pressure-sensitive adhesive.

22. The article of claim 20 wherein said first and second major surfaces of said carrier each bear a different said acrylic pressure-sensitive adhesive.

23. The article of claim 18 further comprising a second damageable layer, said second damageable layer comprising a holographic film.

24. The article of claim 23 further comprising a primer coating.

25. The article of claim 18 wherein said carrier comprises linear low density polyethylene.

27. A tamper-indicating article comprising (a) a film of pressure-sensitive adhesive or a pressure-sensitive adhesive-coated tape that can be removed from a substrate surface by stretching the film or tape;

and (b) at least one damageable layer that will separate from component (a) and be sufficiently damaged to provide an indication of tampering when an attempt is made to peel the article from the substrate surface, and wherein after such an attempt component (a) can be stretched and cleanly removed from the substrate without leaving adhesive residue.

28. The article of claim 27 wherein component (a) has less than about 50 percent elastic recovery after it is stretched and removed.

29. The article of claim 27 wherein component (a) comprises a tape that can be removed from the substrate surface by stretching the tape manually and without rupturing the tape during removal.

30. The article of claim 27 wherein during such an attempt the article exhibits intralayer failure and separates into two parts, one remaining bonded to the substrate and the other detaching completely.

31. The article of claim 27 wherein after such an attempt component (a) can be removed in one piece by grasping component (a) and pulling at an angle of less than 45 degrees to the substrate surface.

32. The article of claim 30 wherein the substrate comprises a glass surface, component (a) stretches during removal but does not break, and the bond of the pressure-sensitive adhesive to the glass surface breaks progressively and cleanly.