Patent GB-736886-A (GB)
Title: Improvements in and relating to thickened lubricating oil compositions
Inventor: MATTHEWS JOHN BRYANT
IPC: C10M169/00
Filed: 1953-03-02
Abstract: A lubricating grease or thickened lubricating oil is prepared by mixing a hydrogel of an inorganic colloid with a lubricating oil and such a quantity of a mutual solvent for the lubricating oil and water that a homogeneous liquid phase can be obtained when the mixture is heated, if necessary under pressure, subjecting the mixture to such conditions of temperature and pressure that a homogeneous liquid phase is obtained and distilling off the water and, if desired, the mutual solvent, while maintaining the liquid phase homogeneous. Suitable inorganic colloids are natural or synthetic clays, particularly montmorillonites such as hectorite or Wyoming bentonite, and various metallic oxides, hydroxides, sulphides, silicates, sulphates and chlorides or mixtures of these.  Silica or alkaline earth metal hydroxides or mixtures of these may be employed.  The lubricating oil may be mineral oil, particularly bright stock, or other lubricating oils, or mixtures of these.  Synthetic lubricating oils mentioned are esters of phosphorus acids (e.g. trioctyl phosphate), di(2-ethylhexyl)hexane-phosphonate and bis - 1,3 - (dioctyl(phosphono)butane), esters of aliphatic dicarboxylic acids (e.g. bis(2-ethyl-hexyl)sebacate and bis (iso-octyl) adipate), polymeric oxyalkylene compounds (e.g. polypropylene oxide and copolymers of propylene oxide with ethylene oxide), polymers of glycols (e.g. polymers of trimethylene glycol) and organo-silicon compounds (e.g. liquid polymethylphenyl siloxanes and polymethyl siloxanes).  Examples of mutual solvents are alcohols (e.g. ethyl, propyl, butyl and amyl alcohols, diacetone alcohol, cyclohexanol and methylcyclohexanol), ketones (e.g. diethyl, methyl ethyl, methyl isobutyl, di-isobutyl and dihexyl ketones), ethers (e.g. di-isopropyl, methyl tert.-butyl, methyl tert.-amyl, dihexyl, dioctyl and diphenyl ethers and dioxane), esters (e.g. ethyl acetate, isobutyrate and acetoacetate and methyl propionate), diols (e.g. propylene, butylene and hexylene glycols, and diglycols such as dipropylene and dibutylene glycols), glycol monoalkyl ethers, glycerol mono- or di-alkyl ethers, phenol, cresols, amines (e.g. alkanolamines) and heterocyclic bases (e.g. pyridine and morpholine). Mixtures of mutual solvents may be employed.  The lubricating oil composition may contain a surface-active agent introduced at any desired stage of the process and examples of suitable anionic and cationic surface-active agents are given.  When distilling off the water, not all of the water need be removed.  The final product may be milled or sheared to impart a lubricating grease structure.  In the examples the hydrogel is silica, alumina, or silica-magnesia; the lubricating oil is di-(2-ethylhexyl) sebacate or medicinal paraffin; the mutual solvent is isopropyl alcohol; and the surface-active agent employed in one case is made by condensing epichlorhydrin with aqueous ammonia and converting the product into a partial amide by reaction with an amount of commercial stearic acid equivallent to one third of its basicity. Phenyl-betanaphthylamine is added in one example to act as antioxidant.