Patent ID: 7951757

Claim:
A functional fluid composition comprising: i) an alkoxy glycol component comprising the formula: RO(CH 2 CH 2 O) n H, wherein R is an alkyl group containing 1 to 8 carbon atoms or mixtures thereof, and n is one or more, wherein the concentration of the alkoxy glycol component having n=2 or more is from about 60 weight percent to about 90 weight percent based on the total weight of the composition; ii) from about 5 weight percent to about 25 weight percent of a polyglycol lubricant; iii) an alkoxy gycol borate ester having the formula: [RO(CH 2 CH 2 O) n ] 3 —B, wherein R is an alkyl group containing 1 to 8 carbon atoms or mixtures thereof, n is 2 to 4; and iv) about 0.3 weight percent to about 10 weight percent of an additive package including a corrosion inhibitor wherein the composition has a dry equilibrium reflux boiling point of about 205° C. or more, a wet equilibrium reflux boiling point of about 140° C. or more, and a viscosity of about 1500 cSt or less at a temperature of about −40° C.; the alkoxy glycol component includes an alkoxy glycol having n=2, an alkoxyglycol having n=3, and an alkoxy glycol having n=4 or more; and the concentration of the alkoxy glycol borate ester is less than 4 weight percent.