GB874336A - Clay grease manufacturing process - Google Patents

Abstract

Clay-gelled lubricating greases, which have been treated with a cationic surface active agent, are protected from undesirable hardening on storage by adding to the grease in the presence of not more than 5% by weight water, 0.25-1% by weight (based on the grease) of oil soluble amino-amides formed by reacting fatty acids having 14-22 carbon atoms, preferably 17-19 carbon atoms, with a mixture of polyethylene polyamines, 20-80% by weight of such polyamine mixture comprising polyamines having 2-3 nitrogen atoms, and the remaining fraction being polyethylene polyamines having an average molecular weight of 200-500, preferably 250-400, the ratio of fatty acids to polyamine being 0.3-0.6 eq./eq. and preferably 0.4-0.5 eq./eq. It is preferred that not more than 0.5% by weight of water be present and that the amount of amino-amides added be 0.5-0.8% by weight. The amino-amides are made by reacting the fatty acids, of which preferably at least 50% by weight consist of acids containing at least one double bond, such as oleic, linoleic, linolenic and tall oil acids, with the polyethylene polyamine, for example ethylene diamine, diethylene triamine, or the bottoms product obtained in the manufacture of ethylene diamine by reacting ethylene dichloride with ammonia, in the appropriate proportions at 125-250 DEG C., preferably 190-225 DEG C., for 0.5-16 hours, usually 1-4 hours. The process comprises dispersing the clay, generally a bentonitic clay such as Wyoming bentonite or hectorite, in water in a concentration of 1-4% by weight adding to this dispersion lubricating oil and 40-100%, preferably 60-80%, by weight (based on the clay), of a cationic surface active agent which may be the same amino-amides described above, or the condensate of the reaction product of epichlorhydrin and ammonia with the fatty acids described above, and mixing at 50-85 DEG C. for example by agitation in a turbulent pipeline flow; 1-10% phosphoric acid (based by weight on the clay) may suitably be added to the dispersion of clay in water before addition of cationic surface active agent and oil. The clay is present in an amount of 2-20% by weight of the final grease. The water which separates is removed and the curd which remains subjected to high speed shearing in the form of a thin film, the temperature being so controlled that residual water is flashed out in 1-30 seconds; if required, a further amount of lubricating oil may be added prior to or during dehydration. The amino-amides are then added to the grease, and the mixture heated to 125-210 DEG F., preferably 150-200 DEG F., for 0.5-8 hours, generally 1-4 hours. To this product is then added 0.05-0.25% by weight of water. If required 0.25-1% each of a corrosion inhibitor, such as sodium nitrite, and an oxidation inhibitor, such as phenyl-a -naphthylamine may be incorporated. Specification 703,169 is referred to.