Hydraulic fluids based on borate ester - comprising poly:ethoxylated tri:alkyl metaborate and di:alkyl formal derivs.

摘要

Hydraulic fluids comprise 30-45 pts.wt. of a polyetboxylated trialkyl metaborate (I), 55-65 pts.wt. of a polyethoxylated dialkyl formal R(OC2H4)nO-CH2-O(C2H4O)nR (II) and 1-10 pts.wt. of a basic stabiliser. In (I), n is 2 or 3 and R is 1-4C alkyl). (I) and (II) are pref. prepd. simultaneously by reacting 1 mole of orthoboric acid with 3 moles of R(OC2H4)nOH and 1.1-1.5 moles of HCHO (esp. as paraformaldehyde) in the presence of an acid catalyst (esp. a sulphonated or phosphonated polymer) and an organic water-immiscible solvent (esp. CH2Cl2, CHCl3 or C2Cl3F3). Tbe reaction is pref. effected at 40-70 deg.C with continuous distn. of H2O/HCHO. The fluids have high dry and wet reflux points (e.g. 248-255 and 182-193 deg.C respectively) and good low-temp. viscosity properties.