Abstract: A process for preparing an expandable resin composition comprising the following steps:(a) admixing, at a temperature in the range of about 120 to about 130 degrees C., the following components:(i) 100 parts by weight of a high pressure, low density homopolymer of ethylene;(ii) about 30 to about 200 parts by weight of a high density polyethylene having a melting point higher than the above mixing temperature;(iii) about 2 to about 50 parts by weight of polypropylene having a DSC melting point of not less than about 140 degrees C.; and(iv) about 0.1 to about 2 parts by weight of a silane coupling agent; and(b) admixing, at a temperature in the range of about 120 to about 130 degrees C., 100 parts by weight of the mixture produced in step (a) with 0.5 to 3 parts by weight of one or more chemical blowing agents having a decomposition temperature higher than the above mixing temperature.