Post-it Adhesive

Spencer Silver and Art Fry, 3M, USA, patent 3,691,140 of 1972. The failed super-glue that became office stationery.

Overview

Silver's 1968 microsphere acrylate was too weak for anything, a glue that would not stay stuck. Fry, a choir bookmark sufferer, found the low-tack 3M hero in 1974; patents filed 1972 covered the tiny-bubble adhesive. The 1977 launch flopped until free samples to Boise executives created demand. Post-it notes became a billion-dollar line and a 3M icon of patient innovation. The 3,691,140 patent is the redemption story of imperfection.