There are several factors that are important for the design and effectiveness of adhesive tapes, some of the most crucial among them being adhesion, cohesion, and tackiness. So, what are adhesion, cohesion, and tackiness? And why are they so important?


Adhesion is the connection between two dissimilar materials, i.e., the attachment of an adhesive tape to substrates. The adhesion process is governed by molecular interactions between the substrate surface and the adhesive. This occurs through weak intermolecular interactions and strong chemical bonds.


Cohesionis the bonding of particles within the adhesive that holds the adhesive mass together. The strength of cohesion is determined by:

  • Chemical bonds within the adhesive polymers.
  • Chemical bonds resulting from polymer cross-linking.
  • Intermolecular interactions between molecules in the adhesive.
  • Mechanical adhesion between different adhesive molecules.


Tackiness is known as the primary stickiness of the adhesive. It indicates how quickly a bond forms when the adhesive comes into contact with a surface under very slight pressure. Tackiness is sensitive to various factors, including temperature, processing, properties of the adhered surface, etc.


Shear adhesion determines the tack time of the adhesive. Shear adhesion is the ability of the tape to resist static forces applied in the same plane as the substrate, resisting sliding or deformation.

The relationship between tackiness, adhesion, and cohesion!

It appears that your text is a mix of Russian and English, and it’s a bit fragmented. Here’s a coherent English translation:

The relationship between tackiness and adhesion (stickiness). These two forces provide:

  • How two objects (substrate and backing) can be firmly connected to each other.
  • How quickly, securely, and durably objects adhere to each other.

In addition to cohesion and adhesion, tackiness also plays an important role in the system:

  • Tackiness and cohesion provide short and reversible adhesion, so they play a crucial role in temporary applications.
  • Tackiness and adhesion provide permanent adhesion.
  • Adhesion and tackiness ensure rapid adhesion.

Good adhesion and strong bonding are determined by the adhesive’s bonding. The adhesive’s bonding forces are based on molecular interactions. Adhesives are polymers with a high molecular chain length that are intertwined with each other. Intertwined molecules form internal cohesive bonds in adhesives. Internal bonding strength is directly related to shear strength.

Why do different bonds break down?

Typically, there can be two types of breakdown: adhesion failure and cohesion failure:

Adhesion Failure: Adhesive failure, also known as delamination, is the most common form of bonding breakdown. The adhesive cleanly separates from one substrate and remains attached to the other.

Cohesive Failure: Cohesive failure can be defined as the physical separation of the adhesive material. Instead of delaminating from the applied surface, the adhesive «breaks apart,» leaving adhesive residues on both the application surface and the substrate.

What causes a failure to occur?

  • Contamination due to inadequate cleaning or preparation of the substrate surface before applying the coating.
  • Incorrect use of adhesion promoters.
  • Separation of the adhesive surface due to improper chemical mixing within the adhesive, making it more cohesive.
  • Incorrect application methods.

Sometimes the reason for PSA failure is straightforward: the chosen adhesive does not meet the necessary functional requirements. This can be avoided by selecting the right PSA tape.

Therefore, before choosing a tape, make sure you know:

  • Where and how the tape will be used?
  • What type of stress the PSA tape will be subjected to?
  • What environmental factors the adhesive will be exposed to?
  • How long the adhesive needs to last?
  • To which substrate(s) do you need to adhere the adhesive?

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