Adhesives are widely used in the packaging industry for various purposes; for forming, sealing and labeling boxes, bags, and other types of containers. However, not all adhesives are the same in their qualities. Based on application, some are stronger, some are more permanent, and some stick quicker than others.
To understand how these features can be varied and controlled, let’s go over the 3 forces that are considered while designing a pressure-sensitive adhesive:
TACK: Tack measures how quickly the adhesive bond forms between the adhesive itself and the surface it is being attached to. High tack will require minimal pressure and a short period of contact to produce a strong bond.
ADHESION: Adhesion describes the actual physical attraction between the adhesive and the surface. High adhesion adhesives bond well and stick strongly to substrates.
COHESION: Cohesion is used to describe the inner bond of an adhesive. This means the degree to which the adhesive is able to hold itself together. High cohesion would signify low tearing and high stability within the adhesive.
Let’s look at the types of adhesives based on these features:
Temporary and Reversible Bond Adhesives
In such adhesives, the features of prime importance are tack and cohesion. High tack ensures quick adhesion to the substrate and high cohesion ensures removal without residue. High adhesion would affect the temporary nature of the adhesive.
For these adhesives, adhesion and cohesion are important forces to consider. A balance between adhesion and cohesion ensures a stable bond that is resistant to tearing and sticks strongly to the substrate. Such adhesives usually support heavy loads and are also appropriate for sealing.
For this application, tack and adhesion are of prime importance. Such adhesives stick quickly and firmly.