From the Annals of Innovation -- Bag Tags

Yes, the airline baggage tags. In recounting all the wonderful innovations that have led up to the state of the art in tags, the article has some fascinating stuff about the materials that go into these tags:

Let’s look first at how an ABT is made. In the interconnected, automated, all-weather world of modern aviation, tags must be resistant to cold, heat, sunlight, ice, oil, and especially moisture. Tags also can’t tear—and crucially, if they’re nicked, they must not tear further—as the bag lurches through mechanized airport baggage systems. And the tag must be flexible, inexpensive, and disposable. Plain old paper can’t begin to meet all these requirements. The winning combination is what IATA’s spokesperson described as a “complex composite” of silicon and plastic; the only paper in it is in the adhesive backing.

Bag tags must meet another set of contradictory requirements. They must be easy to attach, but impossible to detach—until, that is, the bag arrives safely at its destination and the traveler wants to detach it. Old tags were fastened with a string through a hole, but mechanized baggage systems eat these for breakfast. The current loop tag, a standardized strip of pressure-sensitive adhesive, looped through a handle and pressed to form an adhesive-to-adhesive bond, debuted with the ABT in the early ’90s. And the ABT, unlike string tags and earlier loop-y tag ideas, is easily attached to items that lack handles—boxes, say. Simply remove the entire adhesive backing and the loop tag becomes a very sticky sticker.

Of course while tags must remain rigorously attached, they must also be easy for passengers to remove. Intermec’s spokesperson raves about the adhesive’s “excellent flow properties”—in layman’s terms, simply grab the loop from the inside, with two hands, and gently pull apart to remove the tag. A couple of other clever innovations: Like the tags themselves, the adhesive must be all-weather. Early adhesives couldn’t cope with extreme cold, so snowy tarmacs would end up littered with detached tags (and lost bags). Also, passengers don’t want sticky residue left on their bag’s handles—so the adhesive’s backing is designed to stay in place on the inside of the loop.