초록 ▼

An improved 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 a liquid indicator, both housed in a vapor-impermeable container. T

An improved 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 a liquid 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 liquid indicator, containing a polydiacetylene, upon contact with the vapor or condensed vapor produces a visual color response, and the vapor must permeate through the vapor-permeable barrier before contacting the liquid indicator, thus creating a characteristic induction period before a color response occurs. Color response occurs substantially simultaneously over the entire observable surface of the liquid indicator upon contact of the liquid indicator with the vapor. 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 liquid indicator employed.

대표청구항 ▼

In a device for monitoring the time-temperature history of an article including: (a) a closed vapor-impermeable container; (b) at least one vapor-permeable barrier within said container; (c) vapor capable of permeating through the permeable barrier; (d) means for providing vapor at a given moment to

In a device for monitoring the time-temperature history of an article including: (a) a closed vapor-impermeable container; (b) at least one vapor-permeable barrier within said container; (c) vapor capable of permeating through the permeable barrier; (d) means for providing vapor at a given moment to said container, said means positioned on one side of the barrier; and (e) at least one indicator, capable of exhibiting a visual color response upon contact with said vapor or condensed vapor, said indicator positioned on the other side of the barrier, whereby the barrier creates an induction period between the moment the vapor is introduced to said container and the moment said indicator exhibits the color response, wherein the entire observable surface of the indicator is contacted by said vapor, producing a color response over said surface entire surface substantially simultaneously, the improvement which comprises said indicator being comprised of a solution of a polydiacetylene indicating compound in a solvent therefor, wherein said solution being capable of exhibiting a visual color response upon contact with said vapor, and said vapor being soluble in said solution.