Viscosity Index Improver Polymer
Viscosity index improvers (VIIs), also known as viscosity modifiers, prevent lubricants from becoming too thin at high temperatures. For example, a cup of honey has a thick, viscous texture at low temperatures, but upon heating, it becomes more fluid and its viscosity decreases. Similarly, if a lubricant's viscosity is too low and too thin, its protective properties will decline, leading to equipment wear and damage.
Viscosity index improvers are polymer additives that expand at high temperatures, thickening the oil and ensuring a more stable, consistent viscosity. This helps the lubricant provide reliable protection in both low and high temperature conditions. They are also used in the formulation of multigrade oils, eliminating the need for seasonal oil changes.
When selecting a viscosity index improver, it is important to consider the requirements of the finished oil. High molecular weight polymers have better thickening efficiency but are more susceptible to mechanical shear, while low molecular weight polymers are more shear stable but require higher processing rates. Some polymers can degrade under the influence of heat and oxidation, so selecting a polymer with high thermal and oxidative stability is crucial.
HeAo offers a wide range of polymer-based viscosity index improvers suitable for various mineral oil lubricants.
