Method of making polyethylene foam

A method of producing a low density polyethylene foam comprising charging an extruder with a polyethylene resin, from about 5% to 30% by weight of an ionomer resin selected from the group consisting of ionically crosslinked copolymers of ethylene/methacrylic acid and ethylene/vinyl acetate, and a nucleating agent, heating said charge so as to melt said resins, injecting an expanding agent mixture consisting of dichlorodifluoromethane and dichlorotetrafluoroethane into said melt charge in an amount of 8% or less by weight and said mixture comprises approximately a 2:1 ratio of dichlorotetrafluoroethane to dichlorodifluorourethane and extruding said melt charge to form said foam.