| 摘要 |
This relates to an improvement of a conventional closure having a tamper evident feature in the form of a safety button. In accordance with the improvement, the surface of the safety button is provided with a coating in the form of a suitable binder incorporating rupturable microcapsules containing an FDA approved colorant. A relatively stiff layer of translucent material overlies an end panel of the closure in position to be engaged by the microcapsules and to effect rupture of the microcapsules when the safety button everts from a lower axial position to an upper axial position and the microcapsules strike against the underside of the layer of translucent material. In order to prevent accidental rupture of the microcapsules prior to the closure being applied to a container, there is incorporated in the coating spacers which normally prevent the rupture of the microcapsules during conditions of manufacture and handling. The colorant carried by the microcapsules will give a clear and irreversable indication of the opening of the container.
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