O-Ring Lexicon

Adhesion

Adhesion is the sticking of an O-ring to its mating surface. It arises from adhesive forces between the seal and the component and can have advantages and disadvantages during installation and movement.

What is adhesion?

Adhesion refers to the sticking between two surfaces in contact — here between the elastomer of the O-ring and the material of the groove or the mating surface. It differs from cohesion, which describes the internal cohesion of a material. In O-rings, adhesion occurs particularly when the seal is under pressure for a long time or is installed at higher temperatures. The material can then stick to the mating surface.

Why adhesion matters for O-rings

In static applications, a certain amount of sticking is usually uncritical. In dynamic seals, however, excessive adhesion can lead to the so-called stick-slip effect: the seal briefly sticks, releases abruptly and then slides. This increases friction and wear and can make the movement uneven. When releasing a stuck seal, there is also a risk that material remains on the mating surface. Suitable lubrication with assembly grease and a good surface finish reduce unwanted adhesion.

The key points at a glance

Adhesion is the O-ring sticking to its mating surface, not its internal cohesion.
Excessive adhesion promotes the stick-slip effect in dynamic seals.
Assembly grease and a good surface finish keep the sticking in check.

For moving seals, we recommend the right material from our range. You'll find the right surface finish of the mating surface in the tolerance data.

You'll find the right material for your application in our range.

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