04212153 is referenced by 72 patents and cites 4 patents.

A laminated indicator which changes in a visually perceptible mode with the passage of time and a method for making such an indicator. At least two layers are provided whereby the molecular migration of an agent in an interior layer to the outermost surface of the exterior layer causes a change which can be visually percepted, e.g., a change in color or shade. Preferred embodiments include the migration of a dye or the migration of an acid or base wherein the outermost layer has the other member of an acid-base pair and a pH indicator.

Title
Time color indicator
Application Number
5/875723
Publication Number
4212153
Application Date
February 7, 1978
Publication Date
July 15, 1980
Inventor
Ernest A Pedicano
Greenwich
CT, US
Reid A Conroy
York
PA, US
Inja K Smith
West Orange
NJ, US
Agis F Kydonieus
New York
NY, US
Agent
Sughrue Rothwell Mion Zinn and Macpeak
Assignee
Herculite Protective Fabrics Corporation
NY, US
IPC
G04F 13/00
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