Patent GB-789381-A (GB)
Title: Improved synthetic lubricating compositions
Inventor: FOWLER BENJAMIN THOMAS
IPC: C10M105/46
Filed: 1954-12-16
Abstract: A lubricating composition, suitable for the lubrication of aviation gas turbine systems, comprises a complex ester having the general structure: <TABS:0789381/III/1> wherein the residues are derived from 2-ethyl hexanol, iso-octanol or iso-nonanol, adipic, azelaic or sebacic acid, and a polyethylene glycol with a molecular weight of about 200, together with 0.1-10 per cent by weight, based on the total composition, of either benzthiazole or an oil-soluble compound consisting of a first benzene ring condensed with a substituted benzene ring, the substituent group or groups being chosen from -OH, -SH, amine, substituted amine, amide and esterified carboxyl groups. The first benzene ring may also carry one or more substituent groups which may be chosen from those listed above and from alkyl, cycloalkyl and phenyl groups.  Suitable oil-soluble compounds of the condensed benzene ring type are a -naphthol, a - or b -naphthylamine and 2,3-, 1,7- or 2,6-dihydroxynaphthalene.  The lubricating compositions may also contain monoesters (e.g. esters derived from oxo acids and oxo alcohols), diesters (e.g. esters of dicarboxylic acids, such as adipic, sebacic and azelaic acids, with 2-ethyl hexanol, iso-octanol, oxo alcohols, ether alcohols or thio-ether alcohols), polyesters, ether esters, glycols, polyglycols, glycol ethers (which may be derived from glycol or polyglycols, which latter may themselves contain ether or thioether linkages), formals, polyformals, complex formals, or blends of two or more of such substances.  In addition, the lubricating compositions may also contain thickening agents, particularly polymethacrylate esters, or polymeric hydrocarbons, or halogenated derivatives thereof, such as polystyrene, polyisobutylene, polyvinyl chloride or the haloprene rubbers.  In the examples, lubricating compositions are described consisting of complex ester (obtained from sebacic acid, 2-ethyl hexanol and polyethylene glycol of molecular weight 200), dioctyl sebacate, dinonyl sebacate, polymethacrylate ester and one of a -naphthol, a - or b -naphthylamine and 2,3-, 1,7- or 2,6-dihydroxynaphthalene.  According to the Provisional Specification, a lubricating composition comprises a complex ester and a minor proportion of an oil-soluble compound comprising a first benzene ring condensed with either a second benzene ring or with a heterocyclic ring, wherein the second benzene ring is substituted with at least one substituent group consisting of a -OH, -SH, amine, substituted amine, amide or ester group, or wherein the heterocyclic ring contains at least one hetero-atom consisting of O, S or N.  The oil-soluble compound may carry a further condensed benzene ring which may or may not be substituted.  In the case of those compounds which contain 3 benzene rings, the molecule may have either the anthracene or the phenanthrene type of configuration.  The complex ester is defined as comprising the reaction product of at least one polyfunctional organic acid and at least one polyfunctional alcohol and comprising the reaction product of at least two of the following compounds: monohydric alcohols, polyhydric alcohols, glycols, polyglycols and monobasic, dibasic and other polybasic organic acids, including hydroxy acids.  Specifications 664,052, 668,663, 732,086 and 763,499 are referred to and Specifications 600,325, 699,440, 706,205 and 708,035 also are referred to in the Provisional Specification.  Reference has been directed by the Comptroller to Specifications 743,571, 757,023 and 776,669.