Lipophylic copolymers comprising polar multi-blocks, process for the preparation thereof and use in lubricating compositions

A lipophilic copolymer comprising polar multi-blocks having general formula (I):

• [(ByAk)s]t(AjCm) (I)
• wherein:
• B represents at least one monomer unit deriving from a lipophilic monomer having general formula (II):
• wherein:
• X represents a hydrogen atom;
• or a methyl group;
• R is selected from C1-C50 alkyl groups, linear or branched;
• A represents at least one monomer unit deriving from a polar monomer selected from:
• (a) compounds having general formula (III):
• wherein X represents a hydrogen atom or a methyl group and n represents an integer from 0 to 4;
• (b) (meth)acrylamide or (meth)acrylamides substituted on the nitrogen atom with one or two C1-C4 alkyl groups, linear or branched, said alkyl groups optionally containing polar functional groups;
• (c) di-(C1-C4)-alkylamino-(C1-C4)-alkyl (meth)acrylates;
• C represents at least one monomer unit deriving from a polar polyfunctional monomer having general formula (IV):
• Z—(W)p (IV)
• wherein:
• Z represents a group containing carbon, hydrogen and, optionally, oxygen;
• W represents a function able to react covalently with an alkyl radical;
• p is an integer or fractional number from 2 to 8;
• y is an integer or fractional number from 2 to 250;
• k is an integer or fractional number from 0 to 90;
• j is an integer or fractional number from 0 to 8;
• m is an integer or fractional number from 2 to 10;
• s is an integer or fractional number from 1 to 20;
• t is an integer or fractional number from 3 to 20;
• provided that at least one between j and k is different from 0.