Preparation Of Advanced Borate Ester Based Brake Fluids

Currently,the advanced vehicle brake fluids(HZY4,HZY5,HZY6)are widely researched and gradually applied to market in China.The development of borate ester based brake fluids is of practical interest in the field.The vehicle brake fluids involve borate ester,additives and formulas of the vehicle brake fluid product.In this work,totally four vehicle brake fluids with three different classes were prepared,including two different HZY4 products,a HZY5 product and a HZY6 product.Based on previous investigation,the continuous synthesis plant for borate ester was successfully implemented in a factory via improvement of the technology and optimization of the operation parameters.At the raw material flow rate of 35.5 kg/h,pre-reaction temperature of 95 ? and reaction temperature of 180? under vacuum(0.095 MPa),borate ester A was synthesized with the equilibrium reflux boiling point(ERBP)of 325?,wet equilibrium reflux boiling point(WERBP)of 217?,kinematic viscosity(-40?)of 1348mm2·s-1,evaporation loss of 89%and water content of 0.42%.To further improve its performance,anazeotropic process was introduced to synthesize borate ester A in laboratory.Results showed that at 120?140? and atmospheric pressure for reaction of about 12 hours,borate ester A with better quality was synthesized with ERBP of 334?,WERBP of 246?,kinematic viscosity(-40?)of 1645 mm2·s-1,evaporation loss of 87%and water content of 0.08%.The azeotropic process was also employed to synthesize borate ester B with much better quality(low evaporation loss),namely,ERBP of 338?,EERBP of 206?,kinematic viscosity(-40?)of 2100mm2·s-1,evaporation loss of 65%and water content of 0.12%.To solve the problems of the factory-developed additive(cannot meet the standard for copper corrosion;black flocs),two new additives were developed through adjusting the proportion of components and introducing new components.1#HZY4 was prepared by using borate ester A,an additive and some diluents(the total proportion of borate ester A and alcohol ranged from 45 to 60%).2#HZY4 was prepared by applying borate ester B,an additive and some diluents(the proportion of borate ester B ranged from 20 to 70%and alcohol ranged from 0 to 30%).A HZY5 and a HZY6 were prepared by applying borate ester B(50?70%)as the single base fluid.Test showed that all the prepared four vehicle brake fluid products meet the standard requirements of GB 12981-2012 for motor vehicle brake fluids.