By Mary Catherine O'Connor
Jan. 10, 2007—
Pliant, a $2 billion manufacturer of packaging products, says it has developed an
RFID-enabled stretch film. The company claims its customers—which include the
U.S. Department of Defense (DOD), as well as pharmaceutical and consumer packaged goods companies—could use the product not only to comply with government or retail RFID mandates, but also to determine whether individual pallets have been tampered with.
Stretch film, also known as stretch wrap, is a clear polyethylene film that clings to itself and typically is used to bind a number of small, individual cases together to create a larger unified load, such as a pallet. Pliant has worked with nanoparticle materials company
NovaCentrix to devise a means of printing an electrically conductive trace into its stretch film using NovaCentrix's silver ink. The conductive trace is printed in two parallel lines, 6 inches apart and 1 to 1.5 inches wide.
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A pallet wrapped with Pliant's RFID-enabled stretch film.
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Once the film is wrapped a number of times around the goods on the pallet, a battery-powered circuit board, electrically connected to a passive
EPC Gen 2 tag, is attached to the end points of the conductive trace with a conductive adhesive. The tag is modified such that it is only readable when the circuit—made complete when the circuit board and tag are attached to the film's end points—is whole.
At the point of receipt of a shipped pallet, a user can attempt to
read the tag using a standard Gen 2
reader. If the stretch film has been cut across any of the circuit trace, thereby breaking the circuit, the tagcannot be read. Moreover, if the conductive trace has been stretched to the point that its electrical resistance exceeds a predetermined level—set by the user and measured by the circuitry—the Gen 2
passive tag is no longer readable. When the pallet is broken down, the circuit board and batteries are removed and the pallet can then be reused.
An unreadable tag is indicative of possible tampering with the contents of the pallet, and the end user would divert the pallet for inspection. To identify the pallet in situations when the stretch film's tag no longer functions, Pliant's system calls for the application of a secondary, standard Gen 2
smart label, encoded with an EPC containing the same product information as the tag linked to the circuit. The two EPCs are stored in a database and linked together, indicating that they both are attached to the same pallet.