Ester oil

Ester oil is a type of synthetic lubricant that's commonly used in the formulation of synthetic oils.
There are three main types of synthetic base oils:

  • Poly Alpha Olefins (PAO): the most popular and widely used base for synthetic and semi-synthetic oils because of its excellent resistance to high temperatures and low volatility.
  • Hydro Cracked Base (HC): a mineral oil that has been hydro-treated to achieve synthetic-like performance. It functions well as a lubricant, but has higher volatility than PAO.
  • Ester Oils: The preferred base oils for many severe applications due to their unique properties that help solve lubrication problems and improve performance. Ester oils have been used in lubrication for over 60 years. In fact, the first synthetic engine oils used in automotive applications were based entirely on ester formulations and were quite successful.


Ester molecules tend to have medium to high polarity because of opposing charges in the molecule. This polarity has some interesting effects on the properties of the oil:


Ester molecules are attracted to positively charged metal surfaces due to their polarity. This causes the molecules to line up on the metal surface and create a tough film with enhanced adhesion properties. This film provides superior lubricity, lower energy consumption and reduced wear.


The intermolecular attraction caused by the polarity of ester oils means that they require more energy (heat) to evaporate from a liquid to a gas state. As a result, the oil maintains its viscosity and quality for a longer period of time and oil consumption due to evaporation is reduced. This makes ester oils ideal for use in high-performance applications where stable lubrication is essential.


The polarity of esters also makes them effective solvents and dispersants, allowing esters to dissolve and scatter impurities such as combustion residues and oil degradation by-products that could otherwise form sludge or varnish deposits within the system. As a result, engine or transmission systems run cleaner and the additives are dissolved more easily in the final lubricant.

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