In 1840, the adhesive postage stamp was first sold in Great Britain. Since then, adhesives have improved greatly, and in 1968 chemists developed these handy little notepapers with an adhesive that allows it to be repositioned with ease.
Legend has it that Art Fry, a chemical engineer for 3M, was singing in his church choir when he hit upon the idea for a removable sticky bookmark. He remembered Silver’s glue, and the sticky note, or Post-it note, as it would come to be known at 3M, was born.
Luckily, Silver’s adhesive turned out to be perfect for Fry’s idea. According to Greg Anderson, technical director of 3M’s office supplies division, the adhesive’s bumpy surface of microspheres allows for a limited number of touchpoints and makes paper coated with the adhesive removable and restickable. Silver adds that the adhesive layer is just the right thickness–about the same thickness as the paper, in fact–to give it the desired stickiness. He also points out that even though the adhesive is as thick as the note it’s stuck to, the microspheres’ size and softness are such that they fit within the structure of the paper when compressed. That’s why, in an unopened package of Post-its, it’s hard to figure out which one is the sticky edge.
There’s also plenty of other chemistry that goes into making the notes. For example, the notes require a coating on one side so that the adhesive stays stuck to the paper. As 3M explains at length on the Post-it website, the company wanted to ensure that the coatings and adhesive wouldn’t render the note unrecyclable.
Visit “What’s That Stuff” to read more about sticky notes.
Excerpted with permission, Chemical & Engineering News
Copyright © 2004 American Chemical Society