Richard Drew, the inventor, had joined 3M in 1923 when it was still just a manufacturer of sandpaper. While testing a new sandpaper in a local auto shop, Drew learned that the two-toned paint jobs popular in the 1920s were difficult, because there was nothing practical that anyone could use to manage the borders.
The first tape only had adhesive along it’s edges but not in the middle. During it’s first test, it fell off the car. A frustrated auto painter growled at Drew: “Take this tape back to those Scotch bosses of yours and tell them to put more adhesive on it!”
(By “Scotch,” by the way, he meant “parsimonious.”)
The nickname stuck — to Drew’s improved masking tape, and to his greatest invention, Scotch Brand Cellulose Tape.