PURPOSE: To prevent refrigerant pollution by using a specific poly-1,4- cyclohexane dimethylene telephtalate (PCT) film.

CONSTITUTION: A biaxial oriented PCT film concurrently satisfying equations I-IV is used for a motor insulating material of an air conditioner or a refrigerator. It is excellent in solvent resistance, it has little low-molecular weight material due to heat deterioration and oxidation deterioration, and the low-molecular weight material is prevented from being eluted to pollute a refrigerant. In the equations I-IV, MP is the crystal melting point °C of the film, ρ is the film density (g/cm3), P is the degree of orientation on the film face, and W is the extraction quantity weight % in 24hr from the film by chloroform.