Regardless of whether the substrate is plastic, paper or cloth, the adhesive force of the tape comes from the layer of adhesive on the surface of the substrate. The physical properties of the adhesive directly determine the adhesive force of the tape. Of course, there are many types of tapes, roughly divided into pressure-sensitive tapes, water-activated tapes, heat-sensitive tapes, etc. Among them, pressure-sensitive tapes are the most used in our lives. No special treatment or activation is required, and it can be achieved with a certain degree of pressing. Adhesive effect. The pressure-sensitive adhesive (also called self-adhesive) on the tape is the focus of our discussion.
Pressure sensitive adhesive is a kind of polymer material with extremely high viscosity and certain elasticity, such as acrylate polymer, rubber, silicone rubber and so on. The adhesiveness of the tape is a strict physical process, divided into two steps of infiltration and adhesion, and the viscoelasticity of the polymer. It plays an important role here: First of all, the viscous adhesive has certain liquid properties, and the surface energy of the adhesive molecule is very low, which makes the adhesive can easily infiltrate the surface of the object, and the elasticity makes When pressed, the adhesive molecules can gather together instead of being squeezed aside; then, the adhesion process is the result of the cohesion and adhesion of the adhesive.
There are some tapes, the adhesion will increase with time. This is because the adhesive needs a longer time to better wet the surface of the object and “flow” into the holes and grooves. In addition, some people think that the tape is just a tape coated with glue. This statement is completely wrong, because the glue is completely in the form of liquid, so as to achieve excellent wettability, and its cohesion and adhesion, It can only be manifested after it is air-dried. Moreover, glue bonding is an irreversible process. Once torn apart, it cannot be re-bonded; and during the entire cycle of tape bonding, the adhesive maintains viscoelasticity, which is a Partially reversible process.