04195056 is referenced by 34 patents and cites 12 patents.

A time-temperature indicator (t-T indicator) is described which is useful for monitoring the shelf lives of various perishable articles. The device is constructed of a vapor-permeable barrier positioned between a vapor and an indicator, both housed in a vapor-impermeable container. The device is activated just prior to the monitoring period by providing vapor to the container, as for example, by rupturing a solvent-filled frangible reservoir. The indicator, upon contact with the vapor produces a visual color response, and the vapor is constrained to permeate through the vapor-permeable barrier before contacting the indicator, thus creating a characteristic induction period before a color response occurs. The time required for the color response to occur in the device is a function of the temperature and time. The induction period can be varied by the thickness and type of material of construction used for the vapor-permeable barrier, the nature of the vapor and the nature of the indicator employed.

Title
Vapor permeation time-temperature indicator
Application Number
5/911629
Publication Number
4195056
Application Date
June 1, 1978
Publication Date
March 25, 1980
Inventor
Gordhanbhai N Patel
Morris Plains
NJ, US
Agent
Gerhard H Fuchs
Robert J North
Assignee
Allied Chemical Corporation
NJ, US
IPC
G01N 21/06
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