The Happy Accident Behind the Invention of Scotchgard

From the humble Post-it^® Note to the surprise discovery of penicillin, sometimes the most impactful innovations are the result of a happy accident. Such was the case for Scotchgard^™, the chemical water repellent developed and sold by 3M.

National Inventors Hall of Fame^® (NIHF) Inductees Patsy Sherman and Samuel Smith transformed an accidental laboratory spill into one of today’s most widely used and recognizable stain repellency and soil removal products. 

Like Water Off a Duck’s Back

In the 1950s, 3M colleagues Sherman and Smith had been tasked with creating a new type of rubber that could be used in the creation of jet fuel lines.

While working in the lab, one of their assistants accidentally dropped a bottle of synthetic latex that she had mixed. “Some of the latex mixture splashed on the assistant’s canvas tennis shoes and the result was remarkable,” Sherman would later recall in an interview.

After examining the shoe, Sherman and Smith were stunned to discover that while the canvas did not change color or texture, it had gained the ability to repel oil, water and other liquids that ran off of it “like water off a duck’s back.”

From Accident to Product

Both chemists realized the commercial potential of the mixture and began working to improve its effectiveness and reduce its cost. After three years of work and collaboration, the team received a U.S. patent and their product hit store shelves as “Scotchgard Protector^™.”

Scotchgard is effective because it is composed of sticky particles on one side and slippery ones on the other. The former allows the chemical to cling to fabric, whereas the latter allows it to resist oil, dirt, water and other liquids.

As permanent press (wrinkle resistant) fabrics became increasingly popular in the 1960s, Sherman and Smith adapted their formula to create a product that “both repelled stains and also permitted the removal of oily soils.”

While at 3M, Sherman and Smith earned 13 patents in fluorochemical polymers and polymerization processes.

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