said core formed of {HEAD ~ polypropylene} and said coating formed of {TAIL ~ polyethylene}, 
said core formed of { HEAD ~ polypropylene } and said coating formed of { TAIL ~ polyethylene } ,
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH