Patent ID: 7985349

Claim:
A colored heat transfer fluid, the heat transfer fluid comprising 0.1 to 90% by weight water, based on the total amount of the heat transfer fluid, an alcohol, and a non-conductive colorant and having a conductivity of no more than or equal to 200 μS/cm, wherein the non-conductive colorant is of the formula: R{Ak[(B) n R 1 ]m}x wherein R is an organic chromophore selected from the group consisting of anthraquinone, triphenylmethane, diphenylmethane, azo containing compounds, disazo containing compounds, trisazo containing compounds, diazo containing compounds, xanthene, acridine, thiazole, two or more conjugated aromatic groups, two or more conjugated heterocyclic groups, and combinations thereof; A is a linking moiety in said chromophore and is selected from the group consisting of O, N and S; B is selected from the group consisting of one or more alkyleneoxy or alkoxy groups containing from 1 to 8 carbon atoms; k is 0 or 1; n is an integer of from 1 to 100; m is 1 or 2; x is an integer of from 1 to 5; and R 1 is H, a C 1 -C 6 alkyl groups, an alkoxy group containing from 1 to 8 carbon atoms, or a combination thereof.