Patent ID: 8766096

Claim:
A production method of a foamed electric wire, whereby a foamed electric wire is obtained via a foamed insulation layer formation step of forming a foamed insulation layer on a conductor, wherein the foamed insulation layer formation step includes: a step of heating pellets of a raw material propylene-based resin at a temperature of 200° C. to less than 270° C. to form a melt; a step of, after forming the melt and before mixing with a foaming agent, reforming pellets from the melt to produce base resin pellets having a shear stress of 0.40 to 0.80 MPa, a step of introducing the base resin pellets into an extruding machine, a step of introducing the foaming agent into the extruding machine, a step of kneading a mixture containing the base resin pellets and the foaming agent, and a step of extruding the mixture from the extruding machine and forming the foamed insulation layer on the conductor.