▁most ▁of ▁the ▁chemical s . ▁It ▁is ▁flexible ▁at ▁room ▁temperature ▁( and ▁low ▁temperature ) ▁and ▁can ▁be ▁heat ▁se aled . ▁Since ▁it ▁is ▁an ▁in exp ensive ▁pl astic ▁it ▁is ▁made ▁in ▁large ▁amounts ▁to ▁c ater ▁demand . ▁For ▁example : ▁▁ ▁Ult ra - high - m ole cular - weight ▁poly eth yl ene ▁( U H MW PE ) ▁is ▁t ough ▁and ▁resist ant ▁to ▁chemical s . ▁It ▁is ▁used ▁to ▁manufact ure ▁moving ▁machine ▁parts , ▁bear ings , ▁g ears , ▁artificial ▁joint s ▁and ▁some ▁bullet proof ▁v ests . ▁▁ ▁High - dens ity ▁poly eth yl ene ▁( HD PE ), ▁rec y cl able ▁pl astic ▁no . ▁ 2 , ▁is ▁commonly ▁used ▁as ▁milk ▁jug s , ▁liquid ▁la und ry ▁d eter gent ▁bott les , ▁out door ▁furn iture , ▁marg ar ine ▁tub s , ▁port able ▁gas oline ▁can s , ▁drink ing ▁water ▁distribution ▁systems , ▁water ▁d rain age ▁pip es , ▁and ▁gro c ery ▁b ags . ▁▁ ▁Med ium - dens ity ▁poly eth yl ene ▁( MD PE ) ▁is ▁used ▁for ▁pack aging ▁film , ▁s acks ▁and ▁gas ▁pip es ▁and ▁f itt ings . ▁▁ ▁Low - dens ity ▁poly eth yl ene ▁( LD PE ) ▁is ▁flexible ▁and ▁is ▁used ▁in ▁the ▁manufact ure ▁of ▁s que e ze ▁bott les , ▁milk ▁jug ▁caps , ▁ret ail ▁store