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