Moving boundary device for monitoring shelf-life of a perishable product

A device for monitoring the time-temperature history of a perishable product having a measurable activation energy of product deterioration comprising:

• a) an indicator tape comprised of a transparent polymer film and affixed thereto at least one water-impermeable matrix layer containing an indicator composition:
• b) an activator tape comprised of a substrate and affixed thereto at least one water-impermeable matrix layer containing in solid solution an activator composition:
• c) a composite matrix, of uniform thickness, comprised of said indicator tape matrix and said activator tape matrix, both being of variable thickness, adhered together by a pressure sensitive adhesive, and said activator composition is capable of diffusing through said composite matrix in a predetermined time to contact said indicator composition producing a visually observable color change in said indicator composition, in which the predetermined time for producing said color change, varies transversely along said composite matrix.

A device for monitoring the time-temperature storage history of a perishable product having a measurable activation energy of product deterioration comprising:

• a) an indicator tape comprised of a transparent polymer film and affixed thereto at least one water-impermeable matrix layer containing an indicator composition:
• b) an activator tape comprised of a substrate and affixed thereto at least one water-impermeable matrix layer containing in solid solution an activator composition:
• c) a composite matrix, formed by bonding together said indicator tape and activator tape matrix layers, and further comprising at least one barrier matrix layer bonded to said activator and indicator matrix layers by at least one water-impermeable pressure sensitive adhesive, and wherein at least one matrix layer is of variable thickness, and said activator composition is 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, in which the predetermined time for producing said color change, varies transversely along said composite matrix.

A device for monitoring the time-temperature storage history of a perishable product having a measurable activation energy of product deterioration comprising:

• a) an indicator tape comprised of a transparent polymer film and affixed thereto at least one water-impermeable matrix layer containing an indicator composition:
• b) an activator tape comprised of a substrate and affixed thereto at least one water-impermeable matrix layer containing in solid solution an activator composition:
• c) a composite matrix, comprised of a plurality of laminated matrix layers, including said indicator tape and activator tape matrix layers, and further comprising at least one barrier matrix layer, of uniform thickness and comprised of two wedge-shaped matrix layers, said barrier layer being laminated to said activator and indicator matrix layers by at least one pressure sensitive adhesive, and said activator composition being capable of diffusing through said composite matrix in a predetermined time to contact said indicator composition producing a visually observable color change in said indicator composition, in which the predetermined time for producing said color change, varies transversely along said composite matrix.

A device for monitoring the time-temperature storage history of a perishable product having a measurable activation energy of product deterioration comprising:

• a) an indicator tape comprised of a transparent polymer film and affixed thereto at least one water-impermeable matrix layer containing an indicator composition:
• b) an activator tape comprised of a substrate and affixed thereto at least one water-impermeable matrix layer containing in solid solution an activator composition:
• c) a composite matrix, formed by bonding together said indicator tape and activator tape matrix layers, by at least one water-impermeable pressure sensitive adhesive, and wherein at least one matrix layer is of variable thickness, and said activator composition is capable of diffusing through said composite matrix in a predetermined time to contact and chemically react with said indicator composition producing a visually observable change in fluorescence of said indicator composition, in which the predetermined time for producing said change, varies transversely along said composite matrix.

A device for monitoring the time-temperature storage history of a perishable product having a measurable activation energy of product deterioration comprising:

• a) an indicator tape comprised of a transparent polymer film and affixed thereto at least one water-impermeable matrix layer containing an indicator composition:
• b) an activator tape comprised of a substrate and affixed thereto at least one water-impermeable matrix layer containing in solid solution an activator composition:
• c) a composite matrix, comprised of a plurality of laminated matrix layers, including said indicator tape and activator tape matrix layers, bonded together by at least one pressure sensitive adhesive, and wherein at least one matrix layer is of variable thickness, and said activator composition is capable of diffusing through said composite matrix in a predetermined time to contact said indicator composition producing a measurable change in the electrical conductance of said indicator composition, in which the predetermined time for producing said change, varies transversely along said composite matrix.

A device for monitoring the time-temperature storage history of a perishable product having a measurable activation energy of product deterioration comprising:

• a) an indicator tape comprised of a transparent polymer film and affixed thereto at least one water-impermeable matrix layer containing an indicator composition positioned below an opaque additive:
• b) an activator tape comprised of a substrate and affixed thereto at least one water-impermeable matrix layer containing in solid solution an activator composition capable of dissolving said opaque additive:
• c) a composite matrix, formed by bonding together said indicator tape and activator tape matrix layers, by at least one water-impermeable pressure sensitive adhesive, and wherein at least one matrix layer is of variable thickness, and said activator composition is capable of diffusing through said composite matrix in a predetermined time to contact and chemically react with said opaque additive to dissolve said opaque additive, producing a visually observable change in said indicator composition, in which the predetermined time for producing said change, varies transversely along said composite matrix.