| abstract |
The present invention is directed to improved oil nsoluble dispersant materials which comprise members nselected from the group consisting of oil soluble salts, namides, imides, oxazolines, or mixtures thereof, of npolyolefin-substituted mono and dicarboxylic acids or their nanhydrides covered as per claim 1 wherein the polyolefin is ncharacterized by number average molecular weight of from nabout 1,500 to 2,500 and a molecular weight distribution of nless than about 3.0, and wherein the dispersant additive ncontains within its structure an average of from 0.7 to 1.3 nmono- or dicarboxylic acid producing moieties (preferably nacid or anhydride moieties) covered as per claim 1 per npolyolefin molecule, and wherein the dispersant material ncontains from 0.5 to 4 equivalents of secondary amine ngroups per equivalent of the mono- or dicarboxylic acid nproducing moieties per molecule, with the proviso that the ndispersant material is further characterized by a Z factor nof from 4,000 to 6,000, wherein the Z factor is determined nby the expression: n nwherein [N] is the total nitrogen content of the dispersant nmaterial expressed in wt% and M n is the polyolefin nnumber average molecular weight. |