Urea thickener for lubricating greases.

Abstract

The present invention relates to a process for preparing a grease comprising a urea synthesis step including the reaction R1 between at least one hydroxyurethane having at least one radical of formula (1) and at least one primary amine having at least one functional group of formula (2) to obtain a urea, said reaction R1 optionally being carried out in the presence of a base oil HB1, the grease being formed (i) in situ during reaction R1 or (ii) in a subsequent step to reaction R1 by mixing said urea with a base oil HB2, HB2 being the same as or different from the base oil HB1 optionally used in reaction R1, where R1 and R1a represent, independently of each other, a hydrogen atom or a group selected from hydrocarbon groups optionally comprising one or more heteroatoms. Figure for the abstract: None