Dispersant and antioxidant additive and lubricating oil composition containing same

A process for the preparation of an additive composition prepared by the steps comprising:

• (A) reacting a polymer prepared from ethylene and at least one C.sub.3 to 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 to C.sub.10 alpha-monoolefin and from about 0 to 15 mole percent of said polyene, said polymer having a number average molecular weight ranging from 1,000 to 45,000 above 80,000, with an excess in equivalence of an olefinic carboxylic acid acylating agent per equivalent weight of said polymer, said process comprising heating said polymer to a molten condition at a temperature in the range of 250.degree. C. to 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 5,500 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-aromatic polyamine compound selected from the group consisting of:
• (a) an N-arylphenylenediamine represented by the formula:
• ##STR13## in which Ar is an aromatic hydrocarbon radical and R.sup.1 is hydrogen, --NH--aryl, NH--arylalkyl, a branched or straight chain radical having from 4 to 24 carbon atoms that can be alkyl, alkenyl, alkoxyl, aralkyl alkaryl, hydroxyalkyl or aminoalkyl, R.sup.2 is NH.sub.2, --(NM(CH.sub.2).sub.n --).sub.m --NH.sub.2, CH.sub.2 --(CH.sub.2).sub.n --NH.sub.2, CH.sub.2 --aryl--NH.sub.z in which n and m has a value from 1 to 10, and R.sup.3 is hydrogen, alkyl, alkenyl, alkoxyl, aralkyl, alkaryl having 4 to 24 carbon atoms,
• (b) an aminocarbazole represented by the formula:
• ##STR14## in which R and R.sup.1 represent hydrogen or an alkyl or alkenyl, radical having from 1 to 4 carbon atoms,
• (c) an aminoindole represented by the formula:
• ##STR15## in which R represents hydrogen or an alkyl radical having from 1 to 14 carbon atoms,
• (d) an amino-indazolinone represented by the formula:
• ##STR16## in which R is hydrogen or an alkyl radical having from 1 to 14 carbon atoms,
• (e) an aminomercaptotriazole represented by the formula:
• ##STR17## (f) an aminoperimidine represented by the formula:
• ##STR18## in which R represents hydrogen or an alkyl, alkenyl, or alkoxyl radical having from 1 to 8 carbon atoms.