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Color changing device for monitoring shelf-life of perishable products

  • US 5,053,339 A
  • Filed: 11/03/1988
  • Issued: 10/01/1991
  • Est. Priority Date: 11/03/1988
  • Status: Expired due to Term
First Claim
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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:

  • 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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