Viscosity Index Improvers

What is a Viscosity Index Improver and What Does it Do? 

Simply put a viscosity index improver (VII) aka viscosity modifier helps a lubricant from becoming too “thin” at high temperatures.  Think of a glass full of honey — at low temperatures the fluid is viscous and thick.  However, after being exposed to heat, the honey flows much more readily and has a lower viscosity.  If a lubricant decreases in viscosity and becomes too thin, the protective properties are diminished which leads to equipment damage and wear. 
 
A viscosity index improver is a complex polymer additive that expands at elevated temperatures to thicken the lubricant and ensure a more stable and consistent viscosity.  This ensures the lubricant fully protects the equipment at both low and high temperatures. Viscosity improvers also allow for the formulation of multigrade oils which removes the need for seasonal oil changes.

When choosing the right viscosity index improver, it is important to consider the requirements of the finished fluid. High molecular weight polymers have better thickening efficiency but are more susceptible to mechanical shear, while lower molecular weight polymers have higher shear stability but must be used at a higher treat rate. Some polymers are prone to thermal and oxidative degradation at high temperatures, so it is important to choose a polymer with higher thermal and oxidative stability.
 

Afton Additive Solutions 

Afton carries a range of Olefin Copolymer (OCP) viscosity index improvers (VII) in their HiTEC® Performance Additive product line. OCP viscosity index improvers come in both liquid and solid form, are oil soluble, and compatible with many different lubricant formulations. Many OCP viscosity improvers are recommended for use in engine oils. An OCP polymer is commonly blended with a detergent package and pour point depressant to formulate multi-grade high performance engine oils. We have highlighted a few key OCP grades below, but Click Here to View the Full VII Portfolio

Olefin Copolymer (OCP) Additives

Polymethacrylate (PMA) Polymers

Afton also carries a variety of Polymethacrylate (PMA) based viscosity index improvers (VII) that can be utilized in a variety of industrial and automotive lubricant formulations. Polymethacrylate polymers are typically recommended for applications that require high shear stability such as driveline lubricants and shear stable hydraulic fluids. 

More than Just Lubricants

Afton's HiTEC® Viscosity Index Improvers can be used in a wide variety of non-lubricant related applications.  The polymers can help thicken or improve viscosity for a number of different product formulations and processes.  If you need to thicken or improve the viscosity index in your fluid, reach out and get a sample of the Afton HiTEC® polymeric additives today!