The most famous name in sticky tape began as an ethnic jibe aimed at the company that made it.
In 1925 Richard Drew was a young lab technician at 3M in St. Paul, Minnesota. The company was then a modest sandpaper maker. Drew noticed that car painters were struggling to mask off areas for two-tone paint jobs. He set out to make a tape that would hold, then peel away without lifting the paint.
His first version had adhesive only along the edges. It fell off during its first trial on a car. The frustrated painter told Drew what to do with it.
The famous wording comes from the Lemelson-MIT Program's profile of Drew. The painter said: "Take this tape back to those Scotch bosses of yours and tell them to put more adhesive on it!" Wikipedia notes a slightly different version. It attributes that one to 3M's own company history, Brand of the Tartan: The 3M Story, published in 1955. In that telling the painter said the "Scotch bosses" shouldn't be so cheap with the adhesive.
MNopedia, the Minnesota Historical Society's encyclopedia, treats the painter story as company legend and notes some uncertainty about the name. Either way, the joke was the same. At the time, calling someone "Scotch" meant calling them stingy. The Lemelson profile says the jab played on a stereotype of Scottish people as tight with money.
3M kept the insult. The improved masking tape was sold under the Scotch name, and the name spread across the company's tape line. In 1930 Drew coated cellophane with adhesive and produced the first transparent tape. 3M sold it as Scotch Brand Cellulose Tape, and that is the product most people now mean by Scotch tape.
The word Scotch itself is a contraction of Scottish, recorded from the 1590s. Etymonline notes that by the mid-1800s many people objected to it because of insulting English phrases built on it. Scots is the older form. Etymonline dates "Scotch Tape" in print to 1945 and its use as a verb to 1955.
3M later leaned into the Scottish theme. A tartan design based on the Wallace tartan arrived in 1945, a year after the kilted mascot Scotty McTape.