The second material for {TAIL ~ the outer core}, {HEAD ~ preferably polyurethane foam}, consists of 100 parts of a resin mixture, a blowing agent, and either 51 or 60 parts isocyanate 
The second material for { TAIL ~ the outer core } , { HEAD ~ preferably polyurethane foam } , consists of 100 parts of a resin mixture , a blowing agent , and either 51 or 60 parts isocyanate
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH