DETERGENT-DISPERSING ADDITIVE TO LUBRICATING OILS FOR INTERNAL COMBUSTION ENGINE AND METHOD OF PREPARATION THEREOF Russian patent published in 1999 - IPC

FIELD: lubricants. SUBSTANCE: additive consists of imide and/or ester and/or ester-amide derivative of product of interaction of polyisobutylene with malonic acid and/or its anhydride. Above- mentioned polyisobutylene with molecular weight 800 to 30000 is brought into graft copolymerization or interaction with copolymer including polyisobutylene succinic anhydride residues and prepared from reactive low-molecular comonomer with molecular weight below 500 and having one double bond or from mixture of such comonomers and maleic acid and/or its anhydride observing molar ratio maleic anhydride/comonomer/polyisobutylene 1.25: 3.5: 1. Interaction product contains on average 1.6-6.0 succinic derivative units per one polyisobutylene chain, concentration of molecules including more than one succinic anhydride residues exceeding 25 wt %. Expansion of molecular weight distribution constitutes less than 70% with regard to initial polyisobutylene. Succinic anhydride residues of copolymer bound to polyisobutylene are brought into contact with compound including at least bifunctional amino and/or hydroxyl groups at ratio from 0.7:1 to 5.5:1. EFFECT: improved working characteristics and compatibility with sealing materials. 9 cl, 5 tbl