General information on lubricants

A lubricant is a blend of different base oils with specific additives that improve the technical characteristics of the base oils.

Lubricants carry out other tasks essential for the effective functioning of the equipment:

Reduce friction between two metal surfaces
Protect mechanical parts from wear and corrosion
Clean and cool them
Act as a sealant between engine segments

A mineral oil is made up of a base obtained directly from oil distillation and additives, which give it properties that improve its performance. In a synthetic oil, the bases are treated physically and chemically, obtaining a higher-quality base and performance. Bear in mind that there are also semi-synthetic lubricants that combine the two, both mineral and synthetic oils.

Yes. Synthetic oils are specially designed to meet the requirements of cutting-edge equipment, or to be used at extreme temperatures and very demanding service conditions.

A synthetic base oil offers the following advantages:

- Longer duration of the oil layer or film on moving parts, which entails higher protection in every sense
- Lower volatility, which decreases oil consumption.
- A very good natural thermal response, which reduces the formation of deposits and black sludge.
- Natural detergent and dispersant power, which improves equipment protection.

In the labeling of containers, the following information must be found:

- The type of lubricant: Mineral, semi-synthetic, synthetic.

- Content Usage advice: performance, benefits.

- CLP information (standardized indications and icons referring to the hazards of chemical products and the measures to be taken in case of risks associated with the lubricant).

- Specifications and Approvals

- SAE viscosity.

In closed drums and stored in temperatures above 0º your oil retains all its qualities. However, in the case of drums that you have already opened, you should close them well, so as to prevent contaminants such as water from entering.

Used oils must always be transferred into the special containers placed by the authorities or be taken to the nearest garage for the authorized waste manager to treat them. The quality of the oils and their biodegradability is improved every day, but these products, at the end of their useful life, contain contaminating particles.

Mineral oil is named after the base that makes it up, a mineral base.
The finished lubricant will be the result of mixing this base with its additives.

Mineral bases are obtained directly from the oil refining process.

The fraction of the lubricant base does not have the optimum characteristics when we get it directly from the distillation tower, so it needs to be subjected to several processes to finish it.

The first thing to do to the base is eliminate impurities by vacuum distillate. The aromatic compounds are subsequently removed. These types of components are highly reactive with certain elastomers, as oil will be passing through a system that is likely to contain seals or other elements made with elastomers. It is important to remove the aromatic compounds from the lubricant base.

Finally, the lubricant waxes are removed so that the pour point of the oil can be lowered. When the temperature decreases, the first thing that condenses in the lubricant mix is waxes, so if we manage to eliminate them, we will increase the base pour point and thus use it for a wider range of temperatures.

Once these processes have been completed, we already have the clean, non-reactive mineral base with seals and an appropriate pour point. This base is then ready for mixing with additives so as to obtain the mineral-based lubricant.

The characteristics of mineral lubricants will be the sum of the characteristics provided by the base and additives. Additives are usually added to improve or add features that the mineral bases themselves do not have. Mineral bases, for example, have very good lubricity capabilities, but they do not have very high viscosity rates, so viscosity varies greatly with temperature. To correct this deficiency, a viscosity-improving polymer is added that prevents the lubricant from losing viscosity with temperature increases. And this is the case with the other characteristics to obtain a well-balanced mineral lubricant with optimum lubrication and protection properties for the system.

Synthetic oils are produced through complex chemical reactions in synthesis plants from specific substances. As they are synthesized, they are oils whose molecules are much more homogeneous and with better properties than mineral oils. These synthetic base oils are known on the market under the name Polyalphaolefins (PAO).

The synthetic base oils are inherently better than minerals, but they are still not enough to satisfy the lubrication requirements of engines, so it is necessary to enhance some properties such as the Viscosity Index and add some others such as detergency and dispersancy (TBN). All this is achieved by the additives accompanying the oil.

The appropriate additives are added to these synthesized bases according to the lubricant oil’s intended use. Some of these additives are:


- Pour point depressants: They reduce the temperature at which the oil starts to crystallize.
- Viscosity index improvers: These significantly reduce the variation of viscosity grade with temperature. Viscosity improvers can break by being subjected to a sharp exertion, in what is called shearing, therefore their properties are affected.
- Antioxidants: Additives that delay the oxidation of the lubricant.
- Detergents-dispersants: These avoid the adhesion of deposits or insolubles on the engine parts. They also neutralize acid produced during combustion.



Synthetic oils are manufactured to withstand the harshest operating conditions and are capable of providing greater performance. Synthetic engine oils are perfectly miscible and compatible with mineral oils. The latest specifications of most vehicle manufacturers require synthetic oils to be able to meet their levels.

Mineral oil is obtained directly from the oil distillation at the refinery. The bases obtained are treated to eliminate waxes, aromatic compounds and naphthene compounds, among others. Synthetic oils are obtained by complex synthesis in chemical plants through reactions. Therefore, synthetic oils are oils customized with the desired properties.

Oils are also considered synthetic in which unwanted compounds are converted into desired molecules rather than being eliminated and their behavior is very similar to those of bases produced by chemical synthesis.

As they are customized, the properties of these oils are better: They are less volatile: As all the molecules are the same, there are no smaller or faster molecules with a greater ability to evaporate. This lower volatility translates into lower oil consumption.

They have less friction: Being customized molecules, they have much less friction than mineral oils. This can be reflected in the following example: If we had to move a table on ball bearings, it would slide much better if the bearings were all equal than if they were of different sizes like the molecules of mineral oils. This lesser degree of friction leads to lower energy consumption when two mobile parts move against each other.

They have more resistance to thermal degradation: Mineral oils have molecules that have greater reactivity with the oxygen in the atmosphere. These molecules make mineral oil have a tendency to oxidize. Synthetic oils are made with molecules that have much less reactivity with oxygen, and their degradation will be much lower than that of mineral oil. This translates into a smaller generation of waste and a longer duration of products, up to 5 times longer.

Synthetic oils naturally have a high viscosity index, so their variation with temperature is lower. Some of the scenarios where synthetic lubricants are to be used are: Very hot or dirty environments, high loads and low speeds or exposure to very cold climates.

Synthetic oils therefore have a longer duration and better properties than mineral oils, which obviously also impact their price, which in many cases is justified.

Safety data sheets are available at https://www.cepsa.es/es/fichas-de-seguridad.

For technical data sheets, see each individual product page.

The semi synthetic base oil is manufactured by mixing two base oils: a mineral base oil and a synthetic base oil. The mineral base is obtained from oil distillation in refineries through physical and chemical treatment.

The synthetic base oil is that which is obtained by complex chemical reactions in processing plants. Semi-synthetic oil, as a mixture of both, has intermediate properties between the two basic types. This mixture of base oils is added to the additives necessary to obtain the properties desired for each lubricant and type of application, since the bases alone are not sufficient for the requirements of the equipment. Semi-synthetic oils are mainly applied in engine and transmissions (transmissions and differentials).