Did you know that Cyanoacrylate glue was discovered twice by the same scientist? During World War II, Dr. Harry Coover discovered the extreme bonding capabilities of glue. However, since it was not germane to his project at the time concerning clear plastic gun sites for rifles, he ignored the findings.
Almost 10 years later, now working at Eastman Kodak, one of his project supervisors tried the formulation on a jet canopy project. This time, Dr. Coover officially recognized the glue’s commercial potential.
Today, Cyanoacrylate glue is used in many industries and is found in a great deal of everyday products. Even with its great popularity, though, there is one aspect of Cyanoacrylate glue that consumers worry about, and that’s its shelf-life. Because the bonding properties of the glue can weaken after a certain period of time, this can be a big set back for consumers. To save money and minimize waste, here are some tips on how to improve your Cyanoacrylate glue’s shelf-life
How Cyanoacrylate Adhesives Work
Chemically, Cyanoacrylate is made up of carbon, oxygen, hydrogen and nitrogen. The separated molecules of Cyanoacrylate, called monomers, link together to form polymers. Once exposed to the humidity in the air, the glue begins to cure.
The monomers of the substance bond on an atomic level, which creates a solid. This atomic-level bonding means that the glue solidifies inside all the microscopic crevices in an object. The molecules form incredibly strong chains, creating a plastic mesh that, when it hardens, has incredible holding strength. One square inch can hold about one ton of weight!
Another interesting piece to remember, is that you don’t need to add water to make the glue work, as the moisture in the air is very effective in starting the chemical process, once you open the glue tube or container. Unfortunately, this property also shortens the shelf life of Cyanoacrylate after you open the container and expose the insides to the moisture in the air.
Best Way to Use Cyanoacrylate Glue
Different types of Cyanoacrylate require different application techniques, so it is important to read the manufacturer’s instructions. In general, you want to have a clean, smooth surface. Once you apply the glue, apply pressure for approximately 30 seconds. Cure rates vary, so allow the glue to cure once applied for whatever time frame the manufacturer recommends.
Shelf Life: Unopened Containers
Newly manufactured, sealed tubes of glue can last between 8 and 12 months. Even though sealed, moisture will eventually seep in and ruin the mixture, causing it to “self-glue.” You can extend the shelf life to the outer limit of 12 months if you store unopened containers in a cool, dark space, between 50 and 70 degrees Fahrenheit to keep condensation from forming. You’ll also want to avoid freezing glue, as the moisture will freeze and condense, and may make contamination even more likely.
You do have the option of refrigerating the glue but you should always make sure you warm the container before use. Otherwise, opening it while cold will speed up the polymerization process even more.
Shelf Life: Opened Containers
An opened container, if you clean the outside of the application tube and store it properly, lasts about 6 to 8 weeks before the remaining Cyanoacrylate polymerizes itself.
Testing
Once you open a container of Cyanoacrylate, if you want to reuse it, you should always test it before doing so to ensure the strength of the adhesive has not degraded.
Other Ways to Extend the Shelf Life
The drier the air, the longer your Cyanoacrylate will last. For example, if cyclical businesses have a choice, use Cyanoacrylate during the winter months. The glue tends to last longer due to the cold, dry winter air.
Other things you can do to extend the shelf life include:
- Store your glue with silica dry packs to absorb the atmospheric moisture near the Cyanoacrylate containers.
- Clogging or resealing the openings slows down the self-polymerization. Anything you can do to keep moisture out of the container opening will help.
- If you only use a small amount of glue for your products, using the pin that comes with the container to help re-seal the opening.
- Wiping off the containers between uses will also help to minimize moisture contamination.
Safety Considerations
Be careful not to store your Cyanoacrylate with cotton, wool or leather, once you have opened the container. If these materials somehow get soaked with Cyanoacrylate, it produces a very intense exothermic reaction, or even fire. This may be a good way to start a fire in the woods in the absence of matches, but it can cause a catastrophe in a manufacturing or assembly plant!
Final Thoughts
Knowing the shelf life of Cyanoacrylate is very important when establishing re-order points for your business. Proper storage techniques can help save your business money and minimize waste.