| 摘要 |
The flush-interval indicator comprises optically-distinguishable indicia printed or otherwise affixed to a display surface of a pouch and normally concealed by a water-soluble opaque layer. The opaque layer may take the form of an external panel secured to the pouch, or a water-soluble layer of the pouch itself which includes pigment to render it opaque and shield the indicator from view. In an alternate construction, a water-soluble external cover is secured to the pouch and fibres from the cover are heat sealed into the pouch's display surface to form a flush indicator that is relatively unreadable when the cover is dry. However, when the pouch is exposed to water, the cover dissolves or disperses, after a sufficient flush-interval has elapsed to reveal the flush indicator formed from the embedded fibres. |
