In the experiment, different substrates were coated with Valspar's epoxy primer and topcoat without pretreatment, and the T-bend method was used to measure the adhesion. The results are shown in Figure 3.7. Generally speaking, the factors that affect the adhesion of the coating include the effect of mechanical bond force, surface free energy, chemical bond force, corrosion resistance of the material surface and other factors. It can be seen from the obtained data that although the roughness of the 108 plate is relatively high, its surface free energy is relatively low and its adhesion is relatively poor. For yellowstone slabs, its roughness is low, but its surface free energy is high. Under the joint action of these two factors, the effect of obvious surface free energy has a relative advantage, so the non-peeling T-bend value of the tape is relatively small. The adhesion is relatively high.
