What are properties of an ideal electrical insulating material?

The properties of an ideal (electrical) insulating material are given below:-

(i)  Low dielectric court (high dielectric constant if used in capacitors for storing energy.)

(ii)  Low power factor.

(iii)  High dielectric strength.

(iv)  High insulation resistance.

(v)  Adequate mechanical strength to face service condition.

(vi)  Resistance to heat and temperature.

(vii)  Low moisture absorption or water proof.

(viii)  Good chemical stability and chemical proof.

(ix)  Fire proof.

(x)  High volume and surface resistivity.

(xi)  Good surface finish and machining.