Base oil used for refrigerant oil composition, refrigerant oil composition and composition used for refrigeration

The invention relates to the field of machine oil used for refrigeration, and discloses base oil used for a refrigerant oil composition, a refrigerant oil composition and a composition used for refrigeration. The base oil contains alkylbenzene oil and esters oil, and the ratio of the kinematic viscosity of the base oil at the temperature of 120 DEG C to that of the base oil at the temperature of 40 DEG C is 0.23-0.30. The usage of the alkylbenzene oil is in favor of obtaining the base oil with low viscosity and excellent comprehensive properties, the alkylbenzene oil and the esters oil with low viscosity and high viscosity index are cooperated for usage, by adjusting the ratio of the kinematic viscosity of the obtained base oil at the temperature of 120 DEG C to that of the base oil at the temperature of 40 DEG C, the base oil which is characterized in that the viscosity cannot be excessively reduced by following with the increased temperature can be formed. under condition that the viscosity of the oil product at low temperature is low, by increasing the viscosity temperature characteristics, the oil membrane thickness under high temperature is increased, boundary lubricity and sealing performance are increased, refrigerating efficiency COP value of a compression machine is increased, and the purpose of energy saving and emission reduction, and environment protection can be finally achieved.