| 摘要 |
<p>A shelf life indicating structure comprises a substrate (3) printed with an oxygen sensitive ink (4) in combination with an oxygen scavenging layer (5). The oxygen scavenging layer (5) prevents oxygen reaching the substrate (3) for a predetermined interval. Once the finite oxygen scavenging capability of the layer (5) is exhausted, oxygen reaches the substrate (3), activating a visible indication such as a colour change, in the ink (4). The substrate (3) end layer (5) may be formed into a patch or label for a package, and covered with an oxygen impermeable layer (6), such as a strip of aluminium foil which can be peeled off to initiate a shelf life indication structure.</p> |
