Rotary viscometers are commonly used to measure the viscosity value (also known as apparent viscosity) of Newtonian or Non-Newtonian materials under specific rotational speeds and spindle configurations. However, for high-polymer materials such as coatings, inks, adhesives, etc., including resins, emulsions, and similar substances, they often exhibit Non-Newtonian behavior.
These materials display varying rheological properties depending on shear rate (related to rotational speed and spindle shape). To compare these properties across different materials, a common method used in coatings and related industries is to measure their shear thinning (Thix index) and thixotropy.
Shear thinning is indicated by a decrease in viscosity with increasing rotational speed, while thixotropy is indicated by comparing viscosities at increasing and decreasing rotational speeds, viscosity recovery, or viscosities before and after high shear. The behavior of viscosity measured after high shear approximates the characteristics of the material soon after application, simulating paint application conditions.
Qualitest offers various types of rheometers tailored to different material rheological properties. Operators can customize measurement programs according to specific requirements, such as automatically adjusting shear rate, and utilize professional software to analyze and understand the materials' rheological properties, including simulations under different application conditions.