Crosslinked polyolefin foam and process for producing same

A process comprising:

• providing, an extruder under extrusion conditions at a temperature from 50° C. to 250° C., and a polymer composition comprising
• (A) from 5 wt % to 10 wt % ethylene/silane copolymer having a first melting temperature Tm1, from 106° C. to 110° C.,
• (B) from 80 wt % to 90 wt % nonsilane functionalized polyolefin that is LDPE, having a second melting temperature, Tm2, from 111° C. to 120° C.,
• (C) from 0.03 wt % to 0.2 wt % of a highly effective silanol condensation catalyst (HEC) that is an aromatic sulfonic acid catalyst, wherein wt % is based on total weight of the polymer composition,
• (D) from 0.1 wt % to 2.0 wt % of a permeability modifier that is an ester of a C10 to C24 fatty acid, and
• (E) a scorch inhibitor;
• introducing, under the extrusion conditions, a physical blowing agent into the polymer composition to form a foamable composition;
• cooling the foamable composition to a foaming temperature that is from 106.1° C. to 116.1° C.;
• propelling the foamable composition from an exit die of the extruder to form a foam composition;
• and
• moisture curing of the foam composition to form a crosslinked foam composition having a density from 0.015 g/cc to 0.100 g/cc and a gel content from 10% to 95%.