GB824612A - Lubricants containing salts of organic-substituted phosphonic acid - Google Patents

Abstract

A lubricant comprises a lubricating oil and a mixed-salt complex thickener (which preferably amounts to 5-30 wt. per cent of the composition). The lubricating oil is preferably mineral, but may be synthetic (e.g. esters such as C8 oxo alcohol ester of C8 oxo acid, di-2-ethylhexyl sebacate, C13 oxo acid diester of tetraethylene glycol, complex esters, phosphate, sulfites and carbonates; halocarbon oils such as chlorotrifluoroethylene polymer; alkyl silicates, methyl polysiloxanes; mercaptols and formals). The thickener comprises alkali and/or alkaline earth metal salts of C7-12 and/or C16-30 (preferably C16-22) fatty acid (preferably 1-20 parts by weight of acid) and C1-5 1-hydroxyalkylphosphonic acid (preferably 2-5 parts by weight of acid) RR1C(OH)PO(OH)2 wherein R is H or C1-4 alkyl and R1 is also H or C1-4 alkyl; the molar ratio of C7-12 and/or C16-30 acid to phosphoric acid to 0.1-10 (preferably 0.3-5) : 1. The thickener may also contain said metal salts of a C1-6 fatty acid or furoic acid [preferably 0-15 (particularly 6-12) parts by weight of acid] in molar ratio to phosphonic acid of 0.5-30 (preferably 5-20) : 1. Examples of fatty acids are C1-6 : formic, acetic, propionic, acrylic and lactic; C7-12 : capric, caprylic, nonanoic and lauric; C16-30 : palmitic, stearic, dihydroxystearic, behenic, montanic, linolenic, linoleic, arachidic, ricinoleic, oleic, hydrogenated fish oil and tallow acids. In specified phosphonic acids, (a) R=H and R1=H, Me, Et, Pr or Bu; (b) R=Me and R1=Me, Et or Pr; (c) R=R1=Et. The composition may contain optionally, e.g. in the proportion of 0.1-10.0 wt. per cent, detergents such as calcium petroleum sulphonate; oxidation inhibitors such as phenylalphanaphthylamine; V.I. improvers such as polyisobutylene; corrosion inhibitors such as sorbitan mono-oleate; pour depressants; dyes; and other grease thickeners. The compositions of the invention are prepared by (a) coneutralization of the fatty acids and the phosphonic acid in the lubricating oil by the addition of a metal (as hereinbefore defined) base (e.g. hydroxide, oxide or carbonate), and heating to 400-700 DEG F. (e.g. 430-600 DEG F.). The temperature may then be allowed to drop, but preferably is maintained for 1/2 to 4 hours (e.g. 1 to 3 hours) and then cooled to about 180-200 DEG F., where conventional additives may be added. The mixture may then be homogenized by, e.g., a Goulin homogenizer or a Charlotte mill, and subsequently cooled. The compositions may also be formed by heating the preformed salts together in the oil. Another process for preparing the compositions comprises (b) reacting a dispersion of whole fat (e.g. tallow, hog fat, lard oil, fish oil, rapeseed oil, mustard seed oil) with 1.5-3.0 times the amount of alkali required for complete saponification at 450-650 DEG F. (e.g. 500-550 DEG F.) until foaming ceases (e.g. for 10-30 mins.), cooling to 200-400 DEG F. (e.g. 250-300 DEG F.), then neutralizing excess alkali with the phosphonic acid, preferably maintaining a temperature of 200-400 DEG F. (e.g. 250-300 DEG F.) for about 20-45 minutes, and cooling. Specific examples (all greases) prepared according to method (a) used the following ingredients: 1-hydroxy - 1 - methylethylphosphonic acid; Hydrofol Acids 51; Wecoline AAC Acid (16% lauric, 28% caprylic, 56% capric acids); glacial acetic acid; sodium hydroxide; hydrated lime; phenylalphanaphthylamine, and mineral lubricating oils respectively 55 and 80 S.U.S. at 210 DEG F. Specific examples (greases) according to method (b) used the following ingredients: mustard seed oil, sodium hydroxide, sodium petroleum sulfonate, mineral lubricating oil 55 S.U.S. at 210 DEG F., 1-hydroxy-1-methylethylphosphonic acid and phenylalphanaphthylamine.