Hello and welcome to a new post in which we uncover the story of Super Glue. It is one of the most famous "happy accidents" in science, involving not just one, but two accidental discoveries by the same man before it reached the public.
Let us start chronologically:
1. The Initial "Failure" (1942)
During World War II, Dr. Harry Coover was a chemist at Eastman Kodak working on a project to develop clear plastic for precision gun sights. He discovered a class of chemicals called cyanoacrylates.
The Problem: The substance was a disaster for gun sights because it was "infuriatingly sticky" and bonded to everything it touched.
The Result: Coover and his team rejected the compound and "threw away the formula," considering it a failed attempt at clear plastic.
2. The Rediscovery (1951)
Nearly a decade later, Coover was overseeing a new project at Eastman Kodak to create heat-resistant polymers for jet plane canopies.
The "Aha!" Moment: His colleague, Fred Joyner, was testing the optical properties of a cyanoacrylate sample and spread a thin layer between two expensive glass refractometer prisms. The prisms fused together instantly, permanently bonding the equipment.
The Realization: While Joyner initially panicked over the ruined prisms, Coover recognized that they had not created a failed plastic—they had discovered an incredible, fast-acting adhesive that required no heat or pressure to bond.
3. Commercial Success and Marketing (1958)
The product was first sold commercially in 1958 under the name Eastman 910.
The TV Stunt: To prove its strength, Coover appeared on the TV show "I’ve Got a Secret," where he used just one drop of the glue between two metal plates to lift the show's host off the ground.
The Rebranding: It was eventually rebranded as "Super Glue" in the 1970s.
4. A Life-Saving Evolution
Beyond household repairs, the adhesive found a critical use during the Vietnam War.
Battlefield Medics: Medics began using a spray version of the glue to instantly seal battlefield wounds. It stopped catastrophic bleeding long enough for wounded soldiers to be transported to a hospital, saving countless lives.
Modern Medicine: This accidental military application led to the development of FDA-approved medical-grade adhesives used in hospitals today, such as Dermabond.
5. How the Bonding Strength Compares
Vs. Epoxies & Structural Acrylics: Two-part epoxies and acrylics have comparable or slightly higher tensile strength (12–25 MPa), but they heavily outperform Eastman 910 in impact, heat, and moisture resistance. Epoxies are highly resilient under mechanical stress, whereas cyanoacrylates are relatively brittle. Eastman 910 is a high-strength, original methyl-cyanoacrylate (super glue) that cures rapidly. It boasts tensile shear strengths of 20–30 MPa on metals like steel. An overview on the achievable shear strength by metal type is shown in Figure 1.
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| Figure 1: Eastman 910 / Permabond 910 - shear strength by metal type. |
Vs. Modern Cyanoacrylates: Because Eastman 910 is an unmodified methyl-cyanoacrylate, its true strength peaks on tight metal-to-metal joints. Modern cyanoacrylate formulations (such as Loctite 401 or Permabond 731) offer similar shear strength but include "toughening" agents that vastly improve flexibility and peel resistance.
Vs. Wood Glues & Hot Melts: Eastman 910 is much stronger in dead tension than traditional wood glues, hot melts, or silicones. However, it fails on porous or rough surfaces, where wood or polyurethane glues excel.
In conclusion - Strengths & Weaknesses
What it does best: Creates an incredibly strong, instantaneous bond in seconds with a very low volume of adhesive required. It is excellent at resisting straight tension/pulling.
Where it falls short: It is brittle, performs poorly under vibration or sudden impact, and has low heat resistance (usually weakening past 80°C).
Which "happy accidents" leading to new polymers are you aware? Let me know in the comments below.
Thanks for reading & #findoutaboutplastics
Greetings,
Herwig
Literature:
[1] https://lemelson.mit.edu/resources/harry-coover#:~:text=Super%20Glue%E2%84%A2,moved%20on%20with%20their%20research.
[2] https://custom-powder.com/accidental-invention-super-glue/#:~:text=In%201942%2C%20chemist%20Dr.,its%20extraordinary%20strength%20and%20reliability.
[3] https://tacticsjournal.com/opinion/2025/01/31/eastman-910-adhesive/
[4] https://www.silitech.ch/en/blog/wissenszentrum-7/permabond-klebstoffe-sortiment-technische-daten-loctite-vergleich-31
