I base oils are usually obtained from the traditional "three old" technology production system, from the production process, the production of Group I base oil mainly basic physical process, without changing the structure of hydrocarbons, production of base oil quality It depends on the content and nature of the feedstock ideal components. Therefore, the class base oils are limited in performance.
Class II base oil through a combination of process (solvent hydrogenation process technology and combined) in the system, mainly in the chemical process technology-based, without limitation raw materials, hydrocarbons can change the original structure. Group II base oils and thus less impurities (aromatic content less than 10%), high content of saturated hydrocarbons, thermal stability and good oxidation resistance, low temperature and soot dispersion properties are better than I base oils.
Group III base oils are obtained with the full hydrogenation process, as compared to Group II base oil, a high viscosity index base oil hydrogenation, also called unconventional base oils (UCBO). Class III base oils on the performance far exceeds I base oils and Group II base oils, especially those with a high viscosity index and low volatility. Some performance III-based oil with poly α- olefin (PAO) is comparable, the price is much cheaper than synthetic oils.
Refers to IV base oils are poly α- olefin (the PAO), ester oils, polyether, silicone oil, fluorine oil, phosphate esters, alkyl benzene, alkyl naphthalene synthetic oil. Wherein the poly α- olefin (PAO) used for producing paraffin decomposition and polymerization of ethylene. PAO according to the degree of polymerization can be divided into low degree, the degree of polymerization, a high degree of polymerization, are used to modulate different oil products. Compared to this type of base oil and mineral oil, no S, P, and metal, since no wax, so pour point is very low, usually below -40 ℃, the viscosity index is generally more than 140. But PAO boundary lubrication is poor. In addition, because it is itself polar small, poor ability to dissolve polar additive, and rubber seals have some shrinkage, but these problems can be by adding a certain amount of ester oil can be overcome.
Other synthetic oils (synthetic hydrocarbons, esters, silicone oil, etc.) except for Class I ~ IV base oil, vegetable oil, recycled base oil collectively V base oils.