GB827704A - Power transmission fluid - Google Patents

Abstract

A power transmission fluid comprises a major proportion of a mineral oil and minor proportions of (i) a C18 or higher aliphatic monocarboxylic acid and (ii) a neutralization product of a C8 or higher aliphatic amine with a mono- or dialkyl acid pyrophosphate having at least 8 carbon atoms. Mineral oils mentioned are high V.I. and low pour-point spray, transformer and S.A.E. 10, 20 and 30 lubricating oils having viscosities from 40 S.U.S./100 DEG F. to 150 S.U.S./210 DEG F. The acid is preferably a C18-30 acid, e.g. stearic, eicosanoic, behenic, cerotic or montanic acid or a mixture thereof. Many examples are given of C8-18 primary and secondary saturated and unsaturated aliphatic amines. Polyamines such as N-alkyl alkylene diamenes, e.g. C12-18 alkyl trimethylene diamines may also be used. Pyrophosphates mentioned are mono- and di-octyl, dodecyl, tetradecyl, hexadecyl, and octadecyl pyrophosphates. The neutralization is exothermic and is generally conducted at 50-100 DEG C., preferably below 80 DEG C., using 1-5 mols. of amine/mol. phosphate, an excess of phosphate being avoided though the product may contain free amine. Optional ingredients mentioned are minor proportions, e.g. 0.1 to 10 wt. per cent of sulphonates, e.g. oil-soluble Na, K, Ca and Ba petroleum, tetra-t-butyl-naphthalene, dinonyl naphthalene, diwaxnaphthalene, diwaxbenzene, stearylbenzene, t-octylphenol, and waxphenol sulphonates; antioxidants such as (i) Ca, Ba and Zn alkyl, cycloalkyl and aryl mono- and dithiophosphates, numerous specific examples being given including the barium salts of P2S5-polybutene or terpene reaction products, and (ii) mixtures of alkyl phenols and arylamines such as mixtures of di- and tri-C1-5 alkyl phenols with phenyl alpha or beta naphthylamine; and anti-foam agents such as silicone polymers of 100-1000 cs./25 DEG C. Exemplary compositions include the following constituents; a refined transformer oil of 56.9 S.U.S./100 DEG F. or a refined lubricating oil of 48 S.U.S./100 DEG F.; 0.2 wt per cent of stearic acid or 0.3 wt. per cent of cerotic acid; 0.2 wt. per cent of the neutralization product of 2 or 5 mols. of a mixture of hexadecyl-, octadecyl-, octadecenyl-, and octadecadienyl-amines or of 4 mols. of a mixture of C12-18 trimethylene diamines (from tallow) with 1 mol. of dioctyl pyrophosphate; 5 p.p.m. of dimethyl silicone polymer; and calcium petroleum sulphonate plus zinc dimethyl cyclohexyl dithiophosphate or 2,6-di-t-butyl-4-methyl phenol plus phenyl-alpha-naphthylamine. The properties of these compositions are compared with similar compositions where the above constituents are replaced or supplemented by other constituents including:-n-octyl and lauryl acid phosphates and di- and tri-octyl phosphates, calcium naphthenate and C14-18 alkyl salicylate, and tricresyl phosphate.