Additives for fuels and oils comprising functionalised diblock copolymers

A process for manufacture of a functionalised diblock copolymer comprising 2 polymeric blocks wherein:

• (i) the first block consists of a chain of ethylenic structural traits, optionally interrupted by one or more structural units derived from 1-alkene co-monomers higher than ethylene, and
• (ii) the second Hock comprises a chain of structural units derived from one or more α,β-unsaturated monomers selected from styrene, substituted styrene, acrylate, methacrylate and diene compounds,
• and wherein said first and second Hocks of the copolymer are terminally joined by means of the following structural linkage:
• wherein each R group independently represents an alkyl or aryl group and R′ represents hydrogen or an alkyl group, and wherein the aromatic ring substituent joined to the second block is positioned meta or para to the aromatic ring substituent joined to the first block;
• the process comprising the following steps:
• a) in a first step, polymerising ethylene, and optionally one or more 1-alkene co-monomers higher than ethylene, in the presence of a metallocene catalyst system to form a first polymer block, being a chain consisting of ethylenic structural units optionally bearing pendent alkyl groups originating from 1-alkene comonomer(s), the reaction being carried out in solution at a temperature of at least 50° C. in the presence of a compound of the formula (I):
• in a reaction vessel pressurised with hydrogen gas, wherein, in the course of the reaction, the compound (I) is terminally incorporated onto the first polymer block resulting in the formation of a terminally unsaturated intermediate of the formula (II):
• b) in a second step, recovering the intermediate (II) from the reaction mixture of the first step;
• and
• c) in a third step, reacting the intermediate (II) at its terminal double bond in a subsequent polymerisation reaction to form a second polymer block, so yielding a diblock polymer of the structure defined above.