| 摘要 |
A lubricating composition, suitable for use in gas turbine bearings, comprises a mixture of a liquid ester having the general formula R1OOC.R.COOR11, wherein R is a divalent saturated hydrocarbon radicle and R1 and R11 are alkyl, aralkyl or cycloalkyl radicles of more than two carbon atoms, and 5-50 per cent, based on the whole composition, of a polyoxyalkylene liquid having a molecular weight of at least 350 and a viscosity higher than that of the liquid ester, the mixture also containing dissolved therein a salt of an aromatic carboxylic acid, of a phenol, or of a phenol-aldehyde condensation product, with a metal of Group II of the Periodic Table in sufficient quantity to give a metal content to the composition of 0.005-1 per cent by weight. Suitable esters are di-(2-ethylhexyl) sebacate, di-(3,5,5-trimethylhexyl) sebacate or adipate or mixtures of these. Metal salts suitable are the calcium or zinc salts of alkylated hydroxy benzoic acids or of condensates of hydrocarbonsubstituted phenols (containing at least 4 carbon atoms in the substituent) with formaldehyde acetaldehyde or a polymer thereof, particularly the calcium salts of p-octyl phenol-paraformaldehyde condensates. The polyoxyalkylene liquids employed are the polyoxyalkylene glycols and their mono- and di-ethers or esters. The composition may also contain 0.05-5 per cent of phenothiazine, thiophenylnaphthylamine, thiodinaphthylamine or a substitution derivative thereof. The aryl radicles in these materials may carry such substituents as alkyl, hydroxy or amino groups or halogen atoms. The amino groups may in turn be substituted with acyl, alkyl, aryl, hydroxy or amino groups. In the examples, lubricating compositions are described consisting of (a) a blend of dinonyl and dioctyl sebacates and dinonyl adipate, (b) a spindle oil solution of calcium salt of p-octyl phenol-paraformaldehyde condensate, (c) phenothiazine and (d) either a polyoxyalkylene liquid known under the Registered Trade Mark "Ucon" or a condensation product of mono-n-butyl ether of ethylene glycol with ethylene and propylene oxides. For comparison purposes, similar lubricating compositions are described in which ingredient (d) is replaced by mineral lubricating oil or a polymerized alkyl ester of methacrylic acid. Specification 768,905 is referred to.ALSO:A lubricating composition for use in gas turbines comprises a mixture of 5-50 per cent by weight of the whole composition of a polyoxyalkylene liquid having a m.w. of at least 350 and a liquid ester of the general formula R1OOC.R.COOR11 where R is a divalent saturated aliphatic hydrocarbon radical and R1 and R11 are alkyl, aralkyl or cycloalkyl radical of more than two carbon atoms, said mixture also containing dissolved therein a quantity of a salt of an aromatic carboxylic acid or of a phenol with a metal of Group II sufficient to give a metal content to the composition of from 0.005 to 1.0 per cent by weight. Preferably the polyoxyalkylene liquid is present in proportion of from 15-40 per cent based on the weight of the whole composition and has a m.w. of 800-4000 and a viscosity of a least 30 seconds at 100 DEG F. The polyoxyalkylene liquids have the general formula R1-O-(R2O)n-R3, wherein R1 and R3 are hydrogen or non-aromatic radical and R2 is an alkylene radical. Liquid copolymers having alternating oxyethylene and oxypropylene blocks are preferred and may be obtained (Example 3) by condensing 118 parts mono-n-butyl ether of ethylene glycol with 60 parts ethylene oxide and condensing the product with 340 parts propylene oxide. Further blocks of ethylene and propylene oxides are added and condensed until a product having a m.w. about 2,500 was obtained. Suitable dicarboxylic acid esters are di-(2-ethylhexyl) sebacate and di(3,5,5-trimethylhexyl) sebacate and metal salts specified are Ca and Zn salts of the condensate of p-octyl phenol and formaldehyde 0.05 per cent of a substituted phenothiazine (thiodiphenylamine) may be added long lists of such substances being given in the Specification. In Example 1, three compositions containing different proportions of a diester oil consisting of 70 per cent dinonyl sebacate, 20 per cent dioctyl sebacate and 10 per cent dinonyl sebacate, a polyoxyalkylene condensate sold as "Ucon" (Registered Trade Mark) the Ca salt specified above, and phenothiazine are given and the viscosities sheer strength and thermal stability of the compositions are compared with similar compositions in which the polyoxyalkylene liquid is replaced by a polymer of an alkylester of methacrylic acid and a solvent refined, dewaxed lubricating oil as described in the parent Specification and in Specification 768,905, [Group III], respectively. |
