| abstract |
Lubricants comprise a major proportion of an ester base and minor proportions of (i) phenothiazines of formula <FORM:1036695/C4-C5/1> where R is an alkyl, aryl, alkaryl, aralkyl, or cyanoalkyl radical at least one of R1, R2, R3 and R4 is an alkyl of alkoxy radical, any other being hydrogen and (ii) a secondary aromatic amine having two aromatic groups directly attached to the nitrogen atom. Esters specified are those formed from C6-C10 aliphatic dicarboxylic acids and C6-C12 branched chain monohydric alcohols, e.g. di-isodecyl azelate, di(3,5,5-trimethyl hexyl)adipate, complex esters, polyesters, e.g. trimethylol propane tripelargonate, pentaerythritol tetraesters or dimers or trimers thereof. The amines specified are diphenylamines and N-aryl naphthylamines. The lubricant may include thickeners, e.g. polyacrylates, polyoxyalkylene glycol ethers, and copolymers of propylene oxide and ethylene oxide; extreme pressure additives, e.g. phosphorothionates, phosphate esters with or without secondary amines such as dimethyl-(3,5-ditertiary butyl-4-hydroxy benzyl) amine; diaryl haloalkyl phosphates such as diphenyl-2,2-bis(chloromethyl)3-chloropropyl phosphorothionate; chlorinated di- and poly-phenyls; polymers of oxetanes of formula <FORM:1036695/C4-C5/2> where one X is chlorine or bromine and the others are chosen from hydrogen, chlorine or bromine; monochloromethyl phosphonic acid salts of tertiary alkyl primary amines; anti-oxidants such as alkylated phenols and bisphenols; metal deactivators and anti-corrosives, e.g. triazoles, pyrridylamines, sebacic, azelaic or adipic acids, and metal petroleum sulphonates; and anti-foaming agents, e.g. polydimethyl siloxanes. |