Self-containing tamper evident seal
US5798169A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 3, 1996 |
| Grant date | Aug 25, 1998 |
| Priority date | — |
| Expiry date | Dec 3, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31938
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A seal (12) that provides visual evidence if the seal is forced open or cooled below a breakdown temperature. The seal (12) includes a plastic strip (20), a layer of ink (22) printed on a surface of the plastic strip (20), and a layer of pressure-sensitive adhesive (24). The seal (12) can be incorporated into a bag (10) for sealing the bag (10) closed. When the bag (10) is sealed closed, the ink layer (22) is sandwiched between the plastic strip (20) and the adhesive layer (24), and the adhesive layer (24) is adhered to a back wall (18) of the bag (10). If the seal (12) is forced open, the ink layer (22) visibly delaminates from the plastic strip (20). The adhesive layer (24) and the plastic strip (20) are chosen to have different rates of shrinking when cooled, so that when the seal (12) is cooled below its breakdown temperature, the ink layer (22) delaminates. In an alternative embodiment of the plastic strip (20'), two layers (60, 62) of ink are printed onto the plastic strip (20'). The first layer of ink (60) is clear and is printed onto the untreated plastic strip (20') in a pattern. The second layer of ink (62) is opaque and is printed uniformly over the plastic strip (20') a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.