Scotchgard, as you may know, was the invention of Minnesota Mining and Manufacturing, also known as 3M. The name had nothing to do with Scotland, but was intended to be a brand extension of Scotch Tape, even though it had nothing to do with tape, either. It's a miracle Post-It notes weren't called ScotchNotes.
The original formulation was pulled after studies showed it affected the immune system of mice. The chemical, perfluorooctane sulfonate, was phased out in favor of perfluorobutanesulfonic acid.
Anyway, the inventors were Patsy Sherman and Samuel Smith. They perfected the formula, but it began thus:
An accidental spill of a fluorochemical rubber on an assistant’s tennis shoe was the beginning to the invention of the product. After exhaustive attempts to remove the spill failed, Sherman moved her intention from removing the spill to using the spill as a protectant from spills.
Good ol’ days sidenote:
During development of the Scotchgard product in the 1950s, Sherman was required to wait for performance results outside of the textile mill during testing due to a rule at that time that women were not allowed in the mill.