Abstract:
A fire-resistant fluid, particularly suitable as an hydraulic fluid, a lubricant, or a heat transfer medium comprises (a) a major proportion of a chlorinated diphenyl containing 20-60%, preferably 40-55%, by weight of combined chlorine, and (b) a lubrication improving proportion, e.g. 0.1-1% by weight of the fluid, of a salt of formula where M is a polyvalent metal of valency n such as lead, magnesium, cadmium, strontium, aluminium, mercury, tin or nickel but preferably zinc, calcium or barium, R1 and R2 are each a saturated aliphatic or alicyclic, aromatic or substituted aromatic group of 1-30, preferably 3-15, carbon atoms; usually, where R1 is an alkyl group of 5 or less carbon atoms, R2 is an alkyl group of more than 5 carbon atoms. A particularly suitable salt (b) is zinc O : O-dihexyldithiophosphate. The fluid may also contain other chlorinated liquid hydrocarbons such as trichlorobenzene (e.g. in an amount up to 15% of the total chlorinated aromatic hydrocarbon content) or partially chlorinated terphenyl in total amounts up to 50% by weight of the total chlorinated aromatic hydrocarbon content. The composition preferably also contains, as corrosion inhibitor, 0.2-1% by weight, of a reaction product of an alkenyl, sulphurized alkenyl, alkyl or dihaloalkyl succinic acid or anhydride with the condensate of 1 mol. of a polyalkylene polyamine and (X-1) mols. of a monocarboxylic acid (preferably containing 10-30 carbon atoms) or its anhydride or acid halide, X being the number of amino nitrogen atoms in the polyamine; the alkyl or alkenyl substituents of the succinic acid should contain 8-18 carbon atoms. The preferred product is one obtained by reacting 2 mols. of dodecenyl succinic anhydride with the condensate of 1 mol. of oleic acid and 1 mol. triethylenetetramine. The compositions may be formed into greases by the addition of sodium, barium, lithium, potassium or calcium soaps or by addition of a C16-18-dialkyl quaternary ammonium salt of montmorillonite. Other additives which may be incorporated include polymethacrylates; alkylated polystyrenes; condensates of ethylene or propylene oxides with ethylene, propylene or butylene glycols or with alcohols such as butanol, octanol, decanol or tridecanol; pour point depressants; oxidation inhibitors; detergents; corrosion and rust inhibitors; anti-wear agents; lubricity agents; and anti-foaming agents such as silicone polymers. Specification 684,640 is referred to.