The adhesive force

Adhesion describes the adhesive force that prevails at the contact surface between the adhesive and the surface to be bonded. High adhesion therefore means that the adhesive tape has strong adhesion to the substrate.

However, good adhesion alone does not mean that the adhesive tape has good long-term adhesion!

The internal bonding strength

Cohesion describes the internal strength of the adhesive, i.e. how strongly an adhesive holds together within itself. So if the adhesive is very strong, it has a high cohesion. In this case, the molecules of the adhesive are firmly bonded to each other and hold together well.

By the way: adhesives with a low cohesion often leave adhesive residues on the surface after removal.

The tactile adhesion

Tack is a form of adhesion and describes the strength with which the adhesive bonds with the surface to be bonded at the first moment. Thus, if a strong and firm bond is formed even with brief contact and little pressure, the tack is high. For practical purposes, it can be simplified to say that the tougher the adhesive of a tape, the higher the instant tack.

It can be an advantage if the tack is not high. This is desirable, for example, if you want to correct the position of the tape again in the event of incorrect adhesion or if the tape is only to remain on the substrate for a short time. It can then be removed without leaving any residue.

But beware: An adhesive tape with weak immediate adhesion can still offer excellent final adhesive strength!