Adhesives are a necessary part of our everyday lives. We use them to bind just about everything, so it’s essential that adhesives don’t fail in your products. Adhesives form airtight and watertight seals between products and remain intact for a significant periods of time, including up to 100 years. How do you know if your product is using the right kind of adhesion that will last and won’t fail?
At Avomeen, we can help test your adhesives to ensure they will keep things sticking. There are two important concepts involved in adhesive bonding: adhesion and cohesion.
What are Adhesion and Cohesion?
Adhesion: Adhesion is the tendency of different particles or surfaces to stick to each other. This can happen through many different means, but an adhesive must stick to something to work.
Cohesion: Cohesive force is when molecules resist being separated, as opposed to two different elements sticking together. An example of this would be two mutually attractive particles, like H2O molecules, forming into water droplets.
Both cohesion and adhesion are necessary forces in creating an adhesive bond, but there are many ways in which these basic forces can fail.
How Do Adhesives Fail?
Adhesive bonding problems usually occur in one of two categories: adhesive failures or cohesive failures. Cohesive failures occur due to a failure in the bulk layer of the adhesive or the bulk of the adherend (the bonded material). This is generally the less serious method of failure. An adhesive failure is more serious and occurs at the interface between adhesive and adherend. This disbonding can be useful in some cases, like in Post-it notes, certain types of tape, and other materials, but when material are meant to be adhered together, usually not desired.
Most adhesive bond failures can be broken down into a few categories:
- Substrate/Backing Failure
- Adhesion Failure
- Cohesion Failure
There types of adhesive failures can be avoided by testing your products with an independent testing lab, like Avomeen. We can design the right adhesive for your substrates that will help your product stay together for decades.
How Do We Test Adhesive Bonds?
Unfortunately, it’s not realistic to wait 50 years to ensure a bond will remain stuck. You can test adhesives and determine the cause of adhesive failures with tools and methods available in an independent testing lab, like Avomeen. We can rapidly age test adhesives to see how they’ll react over time. We can use analysis involving instrumentation, such as FT-IR to determine the composition of an adhesive. SEM or optical microscopy can be used to locate failure planes and indicate the type of adhesion failure. If you’re experiencing an adhesive failure in your products or need to develop an adhesive, contact Avomeen for help with your needs.