Patent GB-765947-A (GB)
Title: Process for the preparation of lubricating greases
Filed: 1955-01-19
Abstract: Lubricating greases are obtained by dispersing a clay in water to form a hydrosol in which the concentration of the clay is between 0.3 and 0.9 per cent by weight or, if the water contains between 5 and 30 ppm. of alkali metal ions, between 0.1 and 0.9 per cent by weight adding to this hydrosol a surface-active agent and a lubricating oil consisting of silicone fluids such as polymeric dimethyl silicone or methylphenyl silicone or organo silicates such as tetrakis (2-ethyl hexyl) silicate, the surface-active agent being added prior to, or together with the lubricating oil, and dehydrating the mixture the proportion of clay and lubricating oil employed being such that the latter is thickened to a greasy consistency.  The clay may be bentonite, hectorite, saponite, nontronite, or attapulgite, or talc or mica. The slumping properties of the clay are improved by adding a critical amount of a water-soluble acid having a dissociation constant greater than 1.5 X 10-5 at 25 DEG  C. such as phosphoric acid, boric acid, hydrochloric acid, sulphuric acid hydrofluoric acid, acetic acid, propionic acid, lactic acid or citric acid.  The desirable ions may be produced by adding alkali metal salts to the water used such as sodium, potassium or lithium or thiocyanates, citrates, chlorides, bromides, acetates, sulphates or phosphates or halides.  The surface-active agent may be a cationic, anionic or nonionic agent such as ammonium, phosphonium, sulphonium, arsonium and stibonium salts.  Specified compounds are octadecadienyl ammonium chloride or bromide, tetraethanol ammonium chloride, lauryl dimethyl ammonium bromide, didecyl ammonium chloride, dicyclohexyl-ammonium bromide, triphenyl lauryl phosphonium bromide and dimethyl dicetyl ammonium bromide and aluminium stearate and non-ionic surface active agents such as those known under the Registered Trade Marks "Spans" and "Tweens".  Antioxidants such as phenyl - alpha - naphthylamine, 2,6 - di-tertiary butyl - 4 - methyl phenol, methylenedicyclohexananoic acid and the corresponding ethylene and propylene isomers; corrosion-inhibiting agents such as the calcium salts of petroleum sulphonic acids and ammonium and sodium nitrites; and stabilizers such as polyethylene, polyisobutylene or the reaction products of chlorinated naphthalene with sodium ethyl xanthate or the corresponding propyl, butyl, pentyl and hexyl compounds may also be added.  Specifications 672,650, [Group III], 706,772; 709,663, 727,353 and 728,779, [all in Group III], are referred to.ALSO:Lubricating greases are obtained by dispersing a clay in water to form a hydrosol in which the concentration of the clay is between 0.3 and 0.9 per cent by weight or, if the water contains between 5 and 30 ppm. of alkali metal ions, between 0.1 and 0.9 per cent by weight adding to this hydrosol a surface-active agent and a lubricating oil, the surface-active agent being added prior to, or together with the lubricating oil, and dehydrating the mixture the proportion of clay and lubricating oil employed being such that the latter is thickened to a greasy consistency. The oil may be a mineral lubricating oil or a synthetic oil such as bis (2-ethylhexyl) sebacate, esters of acids of phosphorous, such as organophosphates, phosphonates and phosphinates such as tricresyl phosphate, trioctyl phosphate and mixtures, copolymers of ethylene oxide and 1,2-propylene oxide, and fluorocarbons and halogenated aromatics. The clay may be bentonite, hectorite, seponite, nontronite, or attapulgite, or talc or mica.  The slumping properties of the clay are improved by adding a critical amount of a water-soluble acid having a dissociation constant greater than 1.5 X 10-5 at 25 DEG C. such as phosphoric acid, boric acid, hydrochloric acid, sulphuric acid, hydrofluoric acid, acetic acid, propionic acid, lactic acid or citric acid.  The desirable ions may be produced by adding alkali metal salts to the water used such as sodium, potassium or lithium; or thiocyanates, citrates, chlorides, bromides, acetates, sulphates or phosphates or halides.  The surface-active agent may be a cationic, anionic or non-ionic agent such as ammonium, phosphonium, sulphonium, arsonium and stibonium salts.  Specified compounds are octadecadienyl ammonium chloride or bromide, tetraethanol ammonium chloride, lauryl dimethyl ammonium bromide, didecyl ammonium chloride, dicyclohexyl-ammonium bromide, triphenyl lauryl phosphonium bromide and dimethyl dicetyl ammonium bromide and aluminium stearate and non-ionic surface active agents such as those known under the Registered Trade Marks "Spans" and "Tweens."  Antioxidants such as phenyl-alpha-naphthylamine, 2,6-ditertiary butyl-4-methyl phenol, methylene-dicyclohexananoic acid and the corresponding ethylene and propylene isomers; corrosion-inhibiting agents such as the calcium salts of petroleum sulphonic acids and ammonium and sodium nitrites; and stabilizers such as polyethylene, polyisobutylene or the reaction products of chlorinated naphthalene with sodium ethyl xanthate or the corresponding propyl, butyl, pentyl and hexyl compounds may also be added.  Specifications 672,650, 706,772, 709,663, 727,353 and 728,779 are referred to.