The viscosity of solvent-based coatings decreases with increasing temperature, and increases with decreasing temperature. However, since the influence of temperature has to work through internal factors, it has different degrees of influence on the viscosity of different coatings. Generally speaking, temperature has little effect on low-viscosity and Newtonian coatings, but has a great effect on high-viscosity coatings. The lower the coating viscosity, the less the temperature has on the coating viscosity, and vice versa. Since the viscosity index is measured at a constant temperature (23±2°C), the viscosity index is high in summer and low in winter to ensure the storage stability of the coating and the appropriate construction viscosity.
There are many methods for measuring the viscosity of paint, which are applicable to different varieties including finger test and shovel test, as well as falling ball method, bubble method, set shear rate measurement method, flow method and so on.