| abstract |
The invention relates to additives for improving the flow properties at low temperatures and the oxidation stability of hydrocarbon oils, obtained by alkylation of a phenole in the presence of a polar aprotic cosolvent in order to produce a linear alkylated phenol condensed with an aldehyde to produce the low temperature flow improving agent. The invention is characterized in that: a) the composition of the polymers has a number average molecular weight of at least about 3000 and a molecular weight distribution of at least about 1.5; b) in the alkylated phenole reagent the alkyl groups (i) are essentially linear, (ii) have between 6 and 50 carbon atoms, and (iii) have an average number of carbon atoms between 12 and 26; and c) at most about 10 mole percent of the alkyl groups on the alkylated phenole have less than 12 carbon atoms and not more than about 10 mole percent of the alkyl groups on the alkylated phenole have more than 26 carbon atoms. The additives can also be produced in the form of a branched skeleton in which monomer reactants are copolymerized with certain tri or tetrafunctional comonomers. The invention also relates to mixtures of these additives with various hydrocarbon oils, and in particular various middle distillates as well as various compositions of lubricating oils, the flow properties of which at low temperature and the oxidation stability are thus improved. significantly. |