„SHEAR STABILITY“

DEFINITION

Hydraulic Fluid Performance

In oils – as well as in other fluids – long-chain polymers can be used to improve the Viscosity Index (VI). In the DYNAVIS® technology we typically use Poly-(alkyl methacrylate)s (PAMA).


The longer the polymer chain, the higher the probability for its shearing at strong mechanical stress. To achieve the same viscosity index and thickening effect, a smaller quantity of longer molecules can be used, or a higher quantity of shorter, more shear-stable ones.

Advantage of VISCOPLEX® - compared to other Viscosity Index Improvers (VIIs)

In comparison to VIIs based on hydrocarbons like OCP, PIB or HSD, the VISCOPLEX® VII with a relatively small molecular weight in its polymer backbone, achieves both a high Viscosity Index (VI) with a high Shear Stability Index (SSI).

VISCOPLEX® rises to the challenge

At lower temperatures the VISCOPLEX® polymer is folded and mainly interacts with itself. Hydrodynamic volume and thickening effect are relatively small.

At higher temperature levels the VISCOPLEX® polymer unfolds and interacts with more and more oil molecules. As the temperature increases, this leads to a higher hydrodynamic volume which significantly contributes to additional thickening, and thus, a higher viscosity for the fluid.