Cov saw txuas feem ntau siv nrog 4,4'-diphenylmethyl diisocyanate (MDI) txiav tawm prepolymers yog 1,4-butanediol (BDO) thiab hydroquinone bis (2-}hydroxyethyl) ether (HQEE).
Piv rau BDO ua cov saw txuas ntxiv, MDI-based polyurethane elastomers uas tsim nrog HQEE muaj ntau qhov zoo sib xws. Cov no suav nrog kev txhim kho kev ua tau zoo ntawm qhov kub siab, siab dua hardness, muaj zog tsim kua muag, thiab muaj zog dua.
Tsis tas li ntawd, MDI / HQEE systems replicate ntau yam ntawm kev ua tau zoo ntawm MOCA / TDI systems. Cov neeg ua haujlwm pom tau tias HQEE / MDI elastomers pom zoo dua qhov kub thiab txias-ua haujlwm piv rau TDI / MOCA elastomers. Vim li no, MDI / HQEE systems feem ntau pom zoo ua lwm txoj hauv kev rau TDI / MOCA systems.
HQEE tau siv dav hauv ntau daim ntawv thov rau MDI / HQEE elastomers, suav nrog:
Muaj log thiab log tsheb.
Kev ua si nawv thiab chaw ua si lom zem log.
Cov yeeb nkab linings thiab coatings.
Industrial yob npog.
Rollers, gaskets, thiab seals.
Lwm yam kev ua haujlwm siab kawg siv.
Txawm hais tias HQEE ntau yam kev siv thiab qhov zoo dua BDO, cov txheej txheem tseem ntsib teeb meem nrog cov saw txuas ntxiv no.
Cov teeb meem ntawm kev siv HQEE feem ntau yog caij nplooj ntoos hlav los ntawm nws cov yam ntxwv ua. Muaj ob qhov teeb meem tseem ceeb cuam tshuam nrog HQEE:
HQEE has a high melting point (>98 degree / 208 degree F).
HQEE tsis supercool tab sis yuav sai sai crystallize hauv qab nws melting point.
Qhov no yuav tsum tau cua sov melting tso tsheb hlau luam thiab tag nrho cov txheej txheem kab mus rau ~ 110 degree thiab insulating kab los tiv thaiv clogging. Tsis tas li ntawd, xaiv HQEE txwv tsis pub muaj peev xwm ntawm tes-batching.
Tsis tas li ntawd, cov txheej txheem yuav tsum preheat lub prepolymer rau ib ncig ntawm 100 degree ua ntej sib tov nrog HQEE. Txwv tsis pub, HQEE yuav crystallize nyob rau hauv lub mix ua rau "starring" nyob rau hauv kho urethane elastomer. Txhua yam pwm yuav tsum tau preheating rau saum 110 degree.
Ntau cov txheej txheem polyurethane txuas ntxiv tso siab rau HQEE yam tsis paub tias cov teeb meem no tuaj yeem txo qis los ntawm qhov tsis paub tsawg dua, tab sis muaj txiaj ntsig zoo, cov saw txuas ntxiv-HER.