| 摘要 |
This relates to a tamper indicating closure which includes a closure cap having a button which is movable between an elevated position and a downwardly recessed position in accordance with the state of closure of an associated container. In particular, the button is provided with a tamper indicating arrangement which will include a first layer directly attached to the button and an overlying second layer which is connected to the button generally at the periphery thereof. The first layer is in the form of a photoactive layer and the second layer is in the form of a friable filter material. Normally the second layer protects the first layer, but when the button changes its shape, the friable filter layer will crack and expose the underlying photoactive layer to cause a change in the photoactive layer. This change could be in the form of the disappearance of a message, including a UPC code or the developing of a previously formed message on the photoactive layer so as to make that message appear.
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