| abstract |
Polar monomer-containing copolymers derived from at least one .alpha., ,.beta. unsaturated carbonyl compound, such as alkyl acrylates and one or more olefins, such olefins including ethylene and C3-C20 .alpha.-olefins such as propylene and 1-butene, which copolymers have (a) an average ethylene sequence length, ESL, of from about 1.0 to less than about 3.0; (b) an average of at least 5 branches per 100 carbon atoms of the copolymer chains comprising the copolymer; (c) at least about 50 % of said branches being methyl and/or ethyl branches; (d) substantially all of said incorporated polar monomer is present at the terminal position of said branches; (e) at least about 30 % of said copolymer chains terminated with a vinyl or vinylene group; (f) a number average molecular weight, Mn, of from about 300 to about 15,000 when the copolymer is intended for dispersant or wax crystal modifier uses and up to about 500,000 where intended for viscosity modifier uses; and (g) substantial solubility in hydrocarbon and/or synthetic base oil. The copolymers are produced using late-transition-metal catalyst systems and, as an olefin monomer source other than ethylene preferably inexpensive, highly dilute refinery or steam cracker feed streams that have undergone only limited clean-up steps. Fuel and lubricating oil additives, particularly dispersants, wax crystal modifiers and flow improvers, are produced. Where functionalization and derivatization of these copolymers are required for such additives it is facilitated by the olefinic structures available in the copolymer chains. |