The application relates to the technical field of cable materials, in particular to an insulating cable material and a preparation method thereof. A large number of'sea-island' interface structures exist in a PP / SEBS blended material body, and charges generated by
electrode injection and polarization are prone to accumulating at the'sea-island' interface, so that
space charge accumulation is caused, and the
voltage breakdown
field strength of the material is reduced. Based on the above problems, the application provides an insulating cable material, wherein long-carbon-chain modified
graphene is added in the
material system; the long
carbon chain makes the nano-
graphene sheet layer structure not prone to agglomeration; the long
carbon chain can also act as a 'bridge' to accelerate the migration speed of carriers in SEBS in all directions, so that the difference between the number of carriers reaching and leaving the'sea-island' interface in the polarization process of the PP / SEBS blended material is reduced, and the
space charge accumulation phenomenon at the interface is effectively improved.