| 摘要 |
The present invention relates to devices for displaying the previous history of products, e.g. in relation to the development of temperature. The device according to the invention comprises a surface layer, an indicator layer, an activator layer and an optional delaying layer. Heating releases moisture which migrates in some embodiments first into the delaying layer and then into the activator layer. Here, an activator is mobilized and migrates together with the humidity into the indicator layer. A colour change occurs as a result of the interaction of the indicator with the activator in the presence of moisture, which change indicates that the critical temperature has been exceeded. The present invention further relates to a method for producing the device according to the invention and to applications of said device, e.g. in monitoring the temperature of sensitive products. |
| 主权项 |
1. A device for displaying previous history of a product, comprising the following layers:
(a) a surface layer (1) impermeable to moisture, (b) an indicator layer (2) comprising at least one indicator, (c) an activator layer (3) comprising at least one activator, and (d) an optional delaying layer (4); wherein the surface layer is positioned over the indicator layer, the activator layer and the delaying layer, the indicator layer is positioned between the surface layer and the optional delaying layer, and the activator layer is absent if an indicator that is activated by H2O is used. |
