Base oils

What are base oils and how do they work?

A base oil makes up the majority of any lubricant formulation. Base oils create the initial lubricating properties when formulating any lubricating oil, which is then modified with the addition of additives.

Base oils are characterised into five groups, the summary of which is shown below. Depending on the specific performance requirements of the finished lubricant, different base oils are chosen.

Base oils as part of a lubricant formulation used here in metalworking gears

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Whitepaper: Esters, the most versatile of base stock technologies

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Base oils are characterised into five groups, the summary of which is shown below. Depending on the specific performance requirements of the finished lubricant, different base oils are chosen.

Base oil category	Treatment	Sulfur %		Saturated%	Viscosity index	General properties
Group I	Solvent refined	>0.03	and /or	<90	80-180	Least refined, mix of hydrocarbons, less clear colour, cheapest
Group II	Hydrotreated	<0.03	and	>90	80-120	More refined mixture of hydrocarbons, clearer colour, lower viscosity than group I
Group III	Hydrocracked	<0.03	and	>90	>120	Even more refined, purer product than I or II, lower viscosity than group I and II
Group IV	Polyalphaolefin (PAO) synthetic lubricants					High viscosity index and oxidation stability, poor biodegradability and incompatibility with seals.
Group V	All other base oils not included in Group I, II, III or IV. Includes our ester and polyalkylene glycol products					Different properties depending on the base oil

Applications

Explore the relevant application areas below to find out more about our ester and PAG base oils.

Ester base oils

Industry leading, broad and diverse family of synthetic Group V base stocks customisable to meet required specifications.

PAG base oils

High performing water soluble, oil soluble and NSF HX-1 (FDA approved) PAG base oils for lubricant oil formulations.

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