Patent ID: 9522972
Filing Date: 2016-12-20
CPC Classification: C08F,C08G,C10M,C10N

Claim Text:
1. A process for preparing an ATRP star-polymer having greater than five, up to 40 arms, comprising the steps of: (1) contacting: wherein n is 0, 1 or 2; m is 0 to 1; X is Cl, Br, I, OR 4 , SR 8 , SeR 8 , OC(—O)R 8 , OP(—O)R 8 , OP(—O)(OR 8 ) 2 , OP(═O)OR 8 , O—N(R 8 ) 2 , S—C(—S)N(R 8 ) 2 ; R an alkyl group with 1 to 20 carbon atoms and containing at least one halogen, in which each hydrogen atom in said alkyl group independently may be replaced by a halide; an alkenyl group with 2 to 20 carbon atoms and containing at least one halogen, or an aralkyl(aryl-substituted alkyl and containing at least one halogen, in which the aryl group is phenyl or substituted phenyl and the alkyl group represents an alkyl with 1 to 6 carbon atoms; R (2) contacting the polymer chain of step (1) with a polyvalent coupling agent to form a star-polymer, wherein the polyvalent coupling agent is a divalent (meth) acrylic monomer, oligomer or polymer thereof or a divalent divinyl non-acrylic monomer, oligomer or polymer thereof; and at least one of steps (3) to (4); (3) contacting the polymer prepared by step (1) or step (2) with a polymerisation inhibitor; (4) mixing the polymer prepared by step (2) or step (3) with an oil of lubricating viscosity to form a lubricating composition.