Crosslinkable polymeric compositions for flexible crosslinked cable insulation and methods for making flexible crosslinked cable insulation

Abstract

Crosslinkable polymeric compositions comprising: (a) a polymer blend comprising: (1) 10 to 94 weight percent, based on the total weight of the crosslinkable polymeric composition, of an ethylene-based interpolymer having the following properties: (i) a density of 0.93 g/cmor less, (ii) a melt index (I) at 190° C. of greater than 0.2 g/10 minutes, and (iii) a shear thinning ratio (V0.1/V100) at 190° C. and 10% strain of less than 8; and (2) 5 to 90 weight percent, based on the total weight of the crosslinkable polymeric composition, of a high-pressure polyethylene; and (b) 0 to less than 40 weight percent, based on the total weight of the crosslinkable polymeric composition, of a filler, where the ethylene-based interpolymer of component (a) is not prepared in a high-pressure reactor or process. Additionally, the polymer blend has the following properties: (i) a shear thinning ratio (V0.1/V100) at 190° C. and 10% strain of at least 5, (ii) a high-shear viscosity (V100) at 190 C and 10% strain of less than 1,300 Pa·s, (iii) a melt strength of at least 4 centiNewtons at 190° C., and (iv) a flexural modulus, 2% secant, of less than 25,000 psi. Such crosslinkable polymeric compositions may be employed as insulation layers in flexible power cables.