Process for the preparation of lubricating oil additives having improved dimensional stability and higher performance at low temperature.

摘要

Procedure for obtaining improvers compounds viscosity index (VII) having an improved and capable dimensional stability to enhance the low temperature rheology of lubricating oils, the above process comprising the treatment of blends of linear polyethylene which is a homopolymer or copolymer ethylene characterized by a crystalline structure and a density between 0, 88 and 0, 94, and copolymers or terpolymers of EP (D) M amorphous, optionally mixed with EP (D) M semicrystalline, carrying out the above treatment in an extruder , carrying out the above treatment in the presence of one or more substances of a hydroperoxide nature and optionally in the presence of 0 to 2% by weight of polyfunctional vinyl monomers, carrying out the above treatment to a value greater shear at 100 s-1 and at a temperature ranging from 75 to 260 ° C, wherein the copolymers or terpolymers of EP (D) M amorphous s above wherein the ethylene content is between 62 and 35% by weight and the content of the third monomer in the terpolymers comprised between 0 and 10% by weight being.