Tikalon Blog by Dev Gualtieri

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Harry Coover and Super Glue

March 29, 2011

Many unique materials have been discovered by accident . Teflon (Polytetrafluoroethylene) was discovered during research on new chlorofluorocarbon (Freon-type) refrigerants. During the course of this research, it was found that a cylinder of tetrafluoroethylene gas contained less gas than its weight would indicate. When an empty cylinder was cut open to discover why this was happening, its insides were coated with a polymer of tetrafluoroethylene, the polymerization reaction having been catalyzed by the iron cylinder.

Polytetrafluoroethylene wasn't the first polymer to have been discovered by accident. polyethylene was produced accidentally when diazomethane was heated. This happened in 1858, but it wasn't until 1935 that a viable commercial process was developed for polyethylene production.

In 1952, a scientist at Corning Glass was doing research on photosensitive glass , when he discovered that an accidental heat-treatment rendered the glass milky white. He found that this glass was particularly resistant to breakage, and so pyroceram , a.k.a. Corningware®, was born.[1] The material attains its unique properties from the fact that the crystallized ceramic inside the glass has very fine dimension. This gives a resistance to crack propagation and increased tensile strength to the hundred MPa (15 ksi ) range. For comparison, the yield strength of A36 structural steel is about 250 MPa (35 ksi).

All these accidental discoveries were not truly accidental. Although the phenomena may have happened by chance, the scientist who correctly observed an opportunity was an important element. As Louis Pasteur said, "In the fields of observation, chance favors only the prepared mind ."[2] It was an observation by the prepared mind of Harry Wesley Coover, Jr. that gave us Eastman 910 , Super Glue and its derivatives. Harry Coover died on March 26, 2011, at the age of 94.[3-5]

Harry Wesley Coover, Jr.

Harry Wesley Coover, Jr.,
on November 17, 2010.
(Screen capture of White house National Medal of Technology and Innovation Ceremony)

Harry Wesley Coover, Jr. was born on March 6, 1917, in Newark, Delaware. Coover earned a Bachelor of Science degree in chemistry at Hobart College , Geneva, New York , and he continued at nearby Cornell University for his M.S. and Ph.D. chemistry degrees. Coover then worked as a chemist at Eastman Kodak , finally serving as a Kodak vice president and director of research and development and new venture management at the Eastman Chemical Division from 1973-1984.[6]

Coover discovered cyanoacrylate , the chemical behind Super Glue, in 1942 while looking for clear plastic materials for gun sights. This class of organics was discounted as being too sticky. It wasn't until 1951, when Coover was looking for a lightweight material for jet fighter canopies , that his coworker, Fred Joyner, attempted to measure the refractive index of their 910th compound. This cyanoacrylate stuck the optical prisms together so tightly that they couldn't be separated. Thus was born Eastman 910, the first Super Glue.[4]

Coover filed a patent application on this discovery in November, 1952, and a patent was issued in 1956.[7] The product was first sold in 1958.[5] The Super Glue patent was just one of Coover's 460 lifetime patents. Coover also patented the use of these adhesives as a means of bonding tissue, and they were used first during the Vietnam War to temporarily mend wounded soldiers. Now, they are often used in many surgical procedures .

ethyl cyanoacrylate

Ethyl cyanoacrylate (ECA), the ethyl ester of 2-cyano-2-propenoic acid.
ECA polymerizes rapidly in the presence of moisture, and it's the material used in Super Glue.
(Via Wikimedia Commons).

Unfortunately, Super Glue did not become a commercial success until its patents expired; or, perhaps we should say, it became a success because its patents expired. So many imitators have entered the market that it's a common and relatively inexpensive household item. Kodak sold its Super Glue business to National Starch in 1980.[4]

Coover was inducted into the National Inventor's Hall of Fame in 2004.[8] He received the National Medal of Technology and Innovation from US President Barack Obama in 2010. Along with his many patents, Coover wrote sixty scientific papers on polymer chemistry .[6] After retirement from Kodak, Coover maintained his interest in the Super Glue industry by becoming president of new business development for Loctite Corporation , Newington, Connecticut . Coover was a member of the board of directors of Reilly Industries (now Vertellus Specialties Inc), Indianapolis, Indiana , for nine years.[6]

Coover appeared on the popular television series, "I've got a Secret ." Coover's secret, of course, was that he had invented this powerful adhesive. As a demonstration on live television, Coover bonded two metal bars together with a drop of the glue. Then, he and host, Gary Moore , were suspended in air on the strength of that instantly-setting bond.[4]

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