In Polyurethanes (PU) manufacturing, precise thermal control is essential to protect reaction selectivity, viscosity consistency, and downstream product quality across prepolymer, dispersion, and specialty PU production. Modern PU plants are commonly designed with reactors rated up to 300°C and -1 to +10 bar, using thermal oil in external half-pipe coils for heating and internal coils for direct cooling, which makes fluid stability and responsiveness critical in both heating and cooling cycles. During prepolymer finishing, unreacted TDI may be removed by thin-film or wiped-film distillation at about 95-100°C, while other distillation routes may operate around 130-150°C; careful temperature control is required to minimize side reactions and oligomer formation. Within this operating window,Eurotherm 330provides fast circulation, excellent low-temperature fluidity, 4.04 mm²/s viscosity at 40°C, and a -68°C pour point for cold start-up and flexible changeovers.Eurotherm 320offers a cost-effective -30 to 320°C range for mainstream reactor and purification duty.Eurotherm 350andEurotherm THTextend service to 350°C with low system pressure and outstanding thermal stability for higher-duty loops. For larger closed systems,RÜTGERS Ruetaflex 1000delivers -55 to 330°C coverage with low viscosity, whileRÜTGERS Ruetasolv BP-Dadds high-temperature durability, low-pour-point performance, and long service life for demanding continuous PU operations.