A method 1 or 2, including blending of {HEAD ~ the material} with {TAIL ~ a foaming agent} which will chemically decompose during the extruding 
A method 1 or 2 , including blending of { HEAD ~ the material } with { TAIL ~ a foaming agent } which will chemically decompose during the extruding
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH