Patent ID: 6295252
Filing Date: 2001-09-25
Classification: A61L,G01N

Abstract:
A migrating dye indicator comprising:a display layer;a base substrate layer;an adhesive layer on one surface of the display layer for adhesively attaching the display layer to the base layer;the base layer including a migrating dye capable of migrating into the adhesive layer of the display layer when the adhesive layer is placed in contact therewith;the adhesive layer containing an accelerator for enhancing the migration of the dye through the adhesive layer;the base layer containing a means for absorbing the accelerator into the base layer;whereby when the adhesive layer on the display layer is contacted with and overlies the base layer, the adhesive layer adhesively attaches the display layer to the base layer, the migrating dye is activated to migrate into the adhesive layer of the display layer in a period of time to cause the formation of an indicia in the display layer after the period of time has elapsed, and the accelerator is absorbed from the adhesive layer into the base substrate to inhibit the migration of the dye through the adhesive layer to thereby minimize the blurring of the indicia after the period of time has elapsed.