Lubricating oil composition

A dispersant additive composition prepared by the steps comprising:

• (A) reacting a polymer prepared from ethylene and at least one (C.sub.3 -C.sub.10) alpha-monoolefin and, optionally, a polyene selected from non-conjugated dienes and trienes comprising from about 15 to 80 mole percent of ethylene from about 20 to 85 mole percent of said (C.sub.3 -C.sub.10) alpha-monoolefin and from about 0 to 15 mole percent of said polyene, with an excess in equivalence of an olefinic carboxylic acid acylating agent per equivalent weight of said polymer, said polymer being obtained by heating a polymer having a number average molecular weight above about 80,000 to a molten condition at a temperature in the range of about 250.degree. C. to about 450.degree. C. and, simultaneously, or sequentially in any order, reducing the molecular weight of said polymer with mechanical shearing means and grafting said olefinic carboxylic acylating agent onto said polymer, thereby producing a grafted, reduced molecular weight polymer having a number average molecular weight ranging from 1000 to 50,000 and having at least 1.8 molecules of said carboxylic acid acylating function grafted onto each copolymer molecule of said reduced polymer;
• and
• (B) reacting said grafted reduced polymer in (A) with an amino-alcohol compound selected from the group consisting of:
• (a) a 2-Anilinoalcohol represented by the formula ##STR15## in which n=1-10 and R.sup.2 is hydrogen or a (C.sub.4 -C.sub.24) alkyl, alkenyl, alkoxyl, alkylaryl or arylalkyl group;
• (b) a (2-Hydroxyalkyl)pyridine represented by the formula ##STR16## in which n=1-10 and R.sup.2 is hydrogen or a (C.sub.4 -C.sub.24) alkyl, alkenyl, alkoxyl, alkylaryl or arylalkyl group;
• (c) a 4-(2-Hydroxyalkyl)morpholine represented by the formula ##STR17## in which n=1-10;
• (d) a 1-(2-Hydroxyalkyl)piperazine represented by the formula ##STR18## in which n=1-10;
• (e) a 1-(2-Hydroxyalkyl)2-pyrrolidinone represented by the formula ##STR19## in which n=1-10;
• and (f) a 1-(2-Hydroxyalkyl)2-pyrrolidine represented by the formula ##STR20## in which n=1-10;
• to produce an ester represented by the formula ##STR21## where R is derived from one of the above amine alcohol compounds.