VISCOSITY INDEX MODIFIERS AND LUBRICANT COMPOSITIONS CONTAINING SUCH VISCOSITY INDEX MODIFIERS

摘要

The invention relates to viscosity modifier polymers, concentrate and lubricant formulations utilizing a diblock polymer having one block A and one block B, block A contributing from 15 to 30% of the total chain length and block B from 70 to 85% of the total chain length, wherein block A comprises at least 93 wt% of ethylene and at least one other alpha-olefin and block B comprises an ethylene content between 40 and 75 wt% and at least one other alpha-olefin and wherein the resulting block copolymer has an average ethylene content of between about 60 wt% to 80 wt% ethylene, a fast Gaussian NMR relaxation signal between 17 and 22% and a slow exponential NMR relaxation signal between 58 and 68% of the total NMR relaxation signal, a SSI of at least 35% and a TE of at least 3.5 in order to obtain improvements in fuel economy.