Pressure-Sensitive Adhesive (PSA) Tape 101: 5 Reasons for Cohesive Failure in Adhesive Tape
Your die-cut part is leaking, it fell off, or it’s just NOT WORKING. So what happened? One possible reason is the adhesive failed.
Adhesive failure can be defined as follows: When the substrates are subjected to a load, failure, or de-bonding, failure happens when the parts separate prematurely. Adhesive or Cohesive are two types of failure, and are pictured below.
This failure mode occurs when the adhesive pulls away from one or both of the substrates, but does not tear or split.
When cohesive failure is present, you will see a physical separation of the adhesive material.
Now that we know what failure is, here are 5 common reasons it happens:
- Inappropriate adhesive. When selecting an adhesive, you have to consider (at a minimum) the substrates being joined, the environment it will be applied & used in, and how long it will have to be operational.
- Environmental Factors. Even if the type of adhesive is appropriate for the application, an unplanned or unexpected change in the environment can cause the adhesive to fail. Heat, cold, moisture, and the introduction of chemicals are all potential culprits.
- Surface Preparation. Careful consideration must be given to the cleanliness of the two substrates. Grease, oil, dust, or dirt are a few examples that can cause poor bonding.
- Improper curing of the adhesive. Adhesives require specific actions in order to cure. Some of those include time, air flow, and the amount of pressure used during application. If any or all of these requirements aren’t followed, failure is possible.
- Lack of elasticity and strength. Flexibility and adhesion levels are critical components to think about when selecting an adhesive. The specific type and amount of stress on the joint must be accounted for. Below are some examples of joint stress.
As you can see, there are many factors that lead to the success or failure of your application. If all of this seems too overwhelming to handle on your own, feel free to call us. We’d be happy to help.