FLUID FOR HIGH-BOILING BRAKE FLUID

摘要

PROBLEM TO BE SOLVED: To provide the subject fluid consisting mainly of a boric ester of polyalkylene glycol monoalkyl ether subjected to no purifying operation such as fractional distillation and meeting the DOT-5 standard. SOLUTION: This fluid for high-boiling brake fluid consists of a composition containing >=50 mass % of a boric ester which is obtained by boric ester modification of a polyether monool composition (a) prepared by adding a 2-4C alkylene oxide to a diethylene glycol mono-1-4C alkyl ether (a0) and comprising 34-98 mass % of an alkylene oxide 1 mol adduct (a1) of (a0), 1-30 mass % of unreacted (a0) and 1-40 mass % of an alkylene oxide >=2 mol adduct (a2) of (a0). This fluid has a boiling point of >=260 deg.C, moist boiling point of >=180 deg.C and dynamic viscosity of <=900 mm2/s at -40 deg.C.