Spencer Silver, a research chemist at 3M who inadvertently created the not-too-sticky adhesive that allows Post-it Notes to be removed from surfaces as easily as they adhere to them, died on May 8 at his home in St. Paul, Minn. He was 80. His wife, Linda, said that he died after an episode of ventricular tachycardia, in which the heart beats faster than normal. Mr. Silver had a heart transplant 27 years ago.

Since their introduction in 1980, Post-it Notes have become a ubiquitous office product, first in the form of little canary-yellow pads — billions of which are sold annually — and later also in different hues and sizes, some with much stickier adhesives. There are currently more than 3,000 Post-it Brand products globally.

Dr. Silver worked in 3M’s central research laboratory developing adhesives. In 1968, he was trying to create one that was so strong it could be used in aircraft construction.

He failed in that goal. But during his experimentation, he invented something entirely different: an adhesive that stuck to surfaces, but that could be easily peeled off and was reusable. It was a solution to a problem that did not appear to exist, but Dr. Silver was certain it was a breakthrough. “I felt my adhesive was so obviously unique that I began to give seminars throughout 3M in the hope I would spark an idea among its product developers,” he told Financial Times in 2010.

Dr. Silver promoted his adhesive for several years within 3M, a company known for its innovative workplace, so assiduously that he became known as “Mr. Persistent.” He patented the adhesive (technically called acrylate copolymer microspheres) in 1972. But two more years passed before someone at 3M paid serious attention to it: Art Fry, a chemical engineer in the tape division lab, who was looking to develop new products.

Mr. Fry had heard about Dr. Silver’s adhesive from a colleague while on the second hole of 3M’s corporate golf course in Lake Elmo, Minn., and decided to attend one of Dr. Silver’s seminars. He didn’t think of an immediate application for the adhesive until one day, while at church choir practice, he realized that he had a problem that Dr. Silver’s invention might solve: The slips of paper that Mr. Fry had been using to bookmark songs in his hymnal kept falling out. So he used a sample of Dr. Silver’s adhesive to create a bookmark that stayed put but didn’t tear the pages when removed.

Mr. Fry tested a similar bookmark on some co-workers, with positive results. But he needed more proof that there was a product 3M might want to pursue. So he sent a report to his supervisor with a note on the front written on a piece of the bookmark; the supervisor responded on the same piece of paper, with the adhesive on part of the other side, and returned it. “It was a eureka, head-flapping moment,” Mr. Fry told Financial Times. “I can still feel the excitement.” In 1993, Mr. Fry received a patent for the Post-it, or technically a “repositionable pressure-sensitive adhesive sheet material.”

Spencer Ferguson Silver III was born on Feb. 6, 1941, in San Antonio. His father, Spencer Jr., was an accountant. His mother, Bernice (Wendt) Silver, was a secretary.

Dr. Silver graduated from Arizona State University with a bachelor’s degree in chemistry in 1962. He earned a Ph.D. in organic chemistry from the University of Colorado, Boulder, four years later. While there, he met Linda Martin, an undergraduate who was working part time in the chemistry department. They married in 1965.

He soon joined 3M as a senior chemist working on pressure-sensitive adhesives. During his 30 years at the company, he rose to the rank of corporate scientist. And while he worked on other projects involving branch block copolymers and immuno-diagnostics, none were part of popular successes like Post-it Notes.

The mating of Dr. Silver’s adhesive and Mr. Fry’s handmade adhesive notes was a hit with 3M secretaries. But 3M executives weren’t so sure.

A test release in 1977 of Press ‘n Peel, as the product was called, in four cities — Denver; Tulsa, Okla.; Tampa, Fla.; and Richmond, Va. — flopped with consumers, who were uncertain about the idea of repositionable paper squares. But the next year, 3M had greater success when it flooded offices in Boise, Idaho, with free samples; 90% of the recipients said they would buy them.

Two years later, 3M introduced Post-it Notes nationally. They have never stopped selling.

Source: New York Times