Abstract: An insulating resin composition for a DC power cable improves DC electrical properties and extrusion stability, and includes (A) a low-density polyethylene having a complex viscosity ?*100, which is measured at 130° C. and a frequency of 100 rad/s, of 600 to 1,300 Pa·s, wherein a ratio (?*0.1/?*100) of a complex viscosity ?*0.1, which is measured at 130° C. and a frequency of 0.1 rad/s, to the complex viscosity ?*100 is 4 or more; (B) a modified polyethylene; and (C) a stabilizer including a mixture of a hindered phenol antioxidant and a thioether antioxidant. The amount of carbonyl groups introduced into the resin composition through the component (B) is 7×10?6 to 1.3×10?5 mol/g relative to the total mass of the component (A), the component (B), and the component (C).

Abstract: Provided is an insulating resin composition for a DC power cable, which insulating resin composition has excellent extrudability, is unlikely to experience sagging, has good scorch resistance, generates a smaller amount of secondary decomposition water, can form an insulating layer that stably exhibits good DC electrical properties, and has high extrusion stability. The insulating resin composition for a DC power cable according to the present invention includes (A) a low-density polyethylene having a complex viscosity ?*100, which is measured at 130° C. and a frequency of 100 rad/s, of 600 to 1,300 Pa·s, wherein a ratio (?*0.1/?*100) of a complex viscosity ?*0.1, which is measured at 130° C. and a frequency of 0.1 rad/s, to the complex viscosity ?*100 is 4 or more; (B) a modified polyethylene; and (C) a stabilizer including a mixture of a hindered phenol antioxidant and a thioether antioxidant. The amount of carbonyl groups introduced into the resin composition through the component (B) is 7×10?6 to 1.