How did a failed glue become the Post-it note?

Spencer Silver, a 3M chemist, was trying to make a strong adhesive and produced one that stuck lightly and peeled off easily. Nobody had a use for it until colleague Art Fry, annoyed by bookmarks falling out of his church choir hymnal, realized it could hold a removable marker. Testing the idea at work showed the real value was in sticky notes for communication. [1] [2]

According to the [invention.si.edu](https://invention.si.edu/invention-stories/art-fry-post-itr-note-inventor) account, Silver was working in 1970 on a strong glue, but the result was super-weak instead. It stuck to objects yet could be peeled away. The [post-it.com](https://www.post-it.com/3M/en_US/post-it/contact-us/about-us/) history says Silver found microspheres that kept their stickiness but could be removed easily, and quotes him saying that his task was to develop bigger, stronger, tougher adhesives and this was none of those. [1] [2]

The German patent office notes that Silver applied for a patent on the acrylate copolymer microspheres on March 9, 1970, and says they formed only a weak pressure-sensitive adhesive. Silver kept promoting it to colleagues for years and called himself "Mr. Persistent." One radio account adds that he once covered a bulletin board with the glue, but that was not a product anyone needed. See [dpma.de](https://www.dpma.de/english/our_office/publications/milestones/inventionsthatmadehistory/post-itanniversary/index.html) and [engines.egr.uh.edu](https://engines.egr.uh.edu/episode/726). [3] [4]

In 1974 Fry, a 3M new-products developer, was singing in his church choir when his paper bookmark fell out of the hymnal. He recalled Silver's adhesive from a seminar and saw that it could make a bookmark that stuck without damaging pages. The next day he made samples, and colleagues began using them as notes and asked for more. Fry said they realized they had "a new way to communicate or organize information." The [invent.org](https://www.invent.org/blog/inventors/art-fry-post-it-notes) account adds that Fry began passing notes to his supervisor on these bookmarks. [1] [2] [5]

Turning the idea into a product took years of work on manufacturing, quality, packaging and sales. Silver and colleagues filed a further patent on February 6, 1973 for a removable adhesive sheet material. In 1977 the notes were released in four cities as "Press 'n Peel" with mixed results. 3M then ran a large sampling effort in Boise, Idaho, and the post-it.com history says 90 percent of those who tried the product said they would buy it. The product reached US stores nationally as Post-it Notes on April 6, 1980, per the German patent office and 3M. [1] [3] [5] [2]

The sources disagree on some details. MoMA dates Silver's discovery to 1968 and describes aerospace adhesive experiments, while the patent office and Smithsonian point to 1970, and the invent.org account describes work on acrylate adhesives for medical, industrial and consumer tapes. The radio account calls Fry a choir director, whereas other sources describe him as a choir member. The 1977 and 1980 dates refer to the trial and national launches respectively. See [moma.org](https://www.moma.org/collection/works/4720). [6] [5] [4]