Heat transfer fluids having low freeze points

Abstract

Heat transfer fluids consisting essentially of about, by weight: A. 20 to about 40 percent diphenyl ether; B. 40 to about 60 percent of a 2-biphenylylphenyl ether (2-bippe) and 4-biphenylylphenyl ether (4-bippe) mixture at a 2-bippe:4-bippe weight ratio of at least about 2:1; and C. 12 to about 25 percent of a polyphenylphenol mixture Exhibit freeze points of -18.degree. C or less. These heat transfer fluids have excellent fluidity over a broad temperature range and display unexpectedly good thermal stability.

Dependencies are inferred from the claim text.