| abstract |
An additive, adapted to improve the viscosity index of a mineral or synthetic lubricating oil, is prepared from polymeric material of very high viscosity boiling above 175 DEG C, and obtained through polymerization of normal alpha-olefines having the general formula R-CH = CH2, wherein R is an alkyl radical containing from 2 to 16 carbon atoms, in the presence of a TiCl4/polyiminoalane catalyst, in a substantially inert atmosphere which may contain hydrogen up to a manometer pressure of 1 kg/cm2, by distilling said polymeric material so that the fraction boiling at a temperature below 350 DEG C at atmospheric pressure is removed therefrom, and catalytically hydrogenating the balance thereof to produce the desired end product. |