Color changing device for monitoring shelf-life of perishable products
First Claim
1. A device for measuring the shelf life of a perishable product having a measurable activativation energy of product deterioration comprising:
- a) an indicator tape comprised of a transparent polymer film and affixed thereto at least one matrix layer containing an indicator composition;
b) an activator tape comprised of a substrate and affixed thereto at least one matrix layer containing an activator composition;
c) a composite matrix, comprised of said indicator tape and activator tape matrix layers, bonded together by at least one water-impermeable pressure sensitive adhesive, said activator composition being capable of diffusing through said composite matrix in a predetermined time to contact and chemically react with said indicator composition producing a visually observable color change in said indicator composition, said device being substantially impermeable to moisture, and said device possessing an activation energy and rate constant for color change which are substantially the same as the activation energy and rate constant for product deterioration of the perishable product in the temperature region of monitoring.
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Accused Products
Abstract
A color changing device for monitoring the time-temperature storage history, i.e. shelf life, of perishable products. The device is constructed of an activator tape, containing an activator composition matrix, an indicating tape, containing an indicating composition matrix and an optional barrier matrix between the activator tape and the indicating tape. At least one matrix is a pressure sensitive adhesive. The activating composition, e.g. an organic acid such as citric acid, diffuses through the barrier and/or indicating matrix to continuously contact the indicating composition, e.g. an acid-base dye indicator such as 2,2'"'"',4,4'"'"',4",-pentamethoxy triphenylmethanol, to produce a visually observable color change at the temperature being monitored. The color intensifies with time and temperature, as more activator composition diffuses into the indicating matrix. The matrices are water-impermeable and the device preferably possesses activation energy and rate constant values for the color change which are substantially the same as those for product decay. This allows accurate and continuously observable monitoring of the abailable shelf-life of the perishable product to which the device is adhered to.
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Citations
18 Claims
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1. A device for measuring the shelf life of a perishable product having a measurable activativation energy of product deterioration comprising:
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a) an indicator tape comprised of a transparent polymer film and affixed thereto at least one matrix layer containing an indicator composition; b) an activator tape comprised of a substrate and affixed thereto at least one matrix layer containing an activator composition; c) a composite matrix, comprised of said indicator tape and activator tape matrix layers, bonded together by at least one water-impermeable pressure sensitive adhesive, said activator composition being capable of diffusing through said composite matrix in a predetermined time to contact and chemically react with said indicator composition producing a visually observable color change in said indicator composition, said device being substantially impermeable to moisture, and said device possessing an activation energy and rate constant for color change which are substantially the same as the activation energy and rate constant for product deterioration of the perishable product in the temperature region of monitoring. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification