Compositions lubrifiantes améliorées

摘要

A lubricant material contains an oleoginous lubricant base together with (a) a dialkyl tin sulphide compound of formula wherein R1 and R2 are the same or different alkyl groups containing 3-6 carbon atoms or (b) a trimeric tin sulphide compound of formula wherein the R1s are methyl or ethyl groups or hydrogen. The lubricant base may be chosen from hydrocarbon oils (e.g. petroleum or polyolefin oils), organosilicon compounds (e.g. polysiloxanes, halogen-substituted polysiloxanes or silicate esters), polyesters (e.g. dialkyl esters of dicarboxylic acids, complex esters, esters formed between polycarboxylic acids and mono- or poly-hydric alcohols, or esters formed between monocarboxylic acids and polyhydric alcohols), fluorocarbon or chlorofluorocarbon oils, aromatic ether oils (which may be halogen-substituted), phosphate esters, tetrahydrofuran/alkene oxide copolymers, polyalkylene glycols or their esters or ethers, polyglycidyl ethers and polythioglycols. The lubricant material may contain additional ingredients such as soaps (e.g. lead oleate, aluminium tristearate, lithium naphthenate or barium oleate), antioxidants or other thickeners, and may be used as a lubricant in electric equipment or as a cutting oil. Where the lubricant material is a grease, it may contain unreacted fat, fatty acids and alkali; unsaponifiable matter including glycerol and fatty alcohols; rosin or wool grease; water; and modifiers or peptizers. In use, the lubricant material may be placed between the rubbing surfaces, the surfaces allowed to rub together at a low initial load while in contact with the lubricant material, and the load gradually increased up to the operating load. In this way, an anti-wear film is believed to be formed on the rubbing surfaces. Alternatively, a break-in lubricant (comprising an organometallic compound of a Group IIIa or IVa metal and a mineral oil) may first be placed between the rubbing surfaces, the surfaces allowed to rub together lightly while in contact with the break-in lubricant, and the break-in lubricant then removed and replaced by the lubricant containing the tin sulphide compound. In the examples, (1) diisopropyl tin sulphide is added to a grease prepared from mineral oil, 12-hydroxy stearic acid, boric acid and quicklime, (2) di-n-butyl tin sulphide is added to a grease prepared from mineral oil, blown asphalt, hydrogenated fish oil fatty acids and litharge, (3)2,2,4,4,6,6-hexamethyl-1,3,5,2,4,6-trithiatristanninane is added to mineral white oil and (4) 2,4,6-triethyl- 2,4,6-trimethyl-1,3,5,2,4,6,-trithiatristanninane is added to a mixture of the o-, m- and p-isomers of bis-(methylphenoxy) benzene.