Patent ID: 7514262

Claim:
A method for monitoring plural functions of goods comprising the steps of: (a) providing a substrate; (b) applying diacetylene monomer to said substrate; (c) polymerizing said monomer to form a coating of polydiacetylene, said coating having properties of (1) changing from a first color irreversibly to a second color immediately upon being subjected to a specified temperature and (2), upon activation upon contact by an activating agent, changing from said first color to said second color at a temperature lower than said specified temperature after a time delay of at least one hour; (d) providing a second layer having at least a first discrete area and a second discrete area; (e) applying said activating agent to said first discrete area but not to said second discrete area; (f) affixing said second layer to said substrate with the activating agent of said first discrete area engaging said coating; (g) maintaining or bringing said affixed coated substrate to a temperature below said specified temperature to cause that portion of the substrate contacted by said first discrete area to change to said second color; and (h) thereafter heating said coated substrate to said specified temperature to cause that portion of the substrate contacted by said second discrete area to change to said second color.