Qhov txawv ntawm MDI Prepolymer vs TDI Prepolymer yog dab tsi?
Polyurethane prepolymersyog cov ntaub ntawv tseem ceeb raw siv hauv cam khwb cia elastomers, rollers, log, cov ntxaij vab tshaus, seals, muaj qhov chaw, nplaum thiab txheej. Ntawm ntau lub tshuab polyurethane, MDI prepolymers thiab TDI prepolymers yog ob hom siv dav tshaj plaws.
Txawm hais tias ob qho tib si yog polyurethane prepolymers uas muaj cov pab pawg isocyanate, lawv muaj qhov sib txawv tseem ceeb hauv cov qauv, kev coj tus cwj pwm, kev ua haujlwm zoo thiab kev siv zaum kawg. Kev nkag siab txog qhov sib txawv no tuaj yeem pab cov tuam txhab xaiv cov khoom tsim nyog tshaj plaws rau lawv cov kev xav tau ntau lawm.
TDI prepolymers yog tsim los ntawm toluene diisocyanate (TDI) thiab polyols. Lub TDI molecule muaj ib lub nplhaib benzene nrog ob pawg isocyanate. Vim tias nws cov qauv yooj yim, TDI nthuav tawm cov kev ua haujlwm siab thiab tsim cov khoom siv polyurethane nrog kev yooj yim heev.
MDI prepolymer yog tsim los ntawm methylene diphenyl diisocyanate (MDI) thiab polyols. MDI muaj ob lub nplhaib benzene txuas nrog tus choj methylene, uas ua rau muaj cov qauv molecular ntau dua. Cov qauv no ua rau muaj zog dua, lub zog thiab thermal stability hauv cov khoom siv polyurethane kawg.
Ib qho ntawm qhov sib txawv tshaj plaws ntawm MDI thiab TDI prepolymers yog lawv cov ntsiab lus NCO thiab viscosity.
Hom TDI prepolymers feem ntau muaj 8% mus rau 15% NCO thiab tswj cov viscosity tsawg. Lawv zoo heev flowability ua rau lawv haum rau casting thiab ua daim ntaub ntawv qhov twg yooj yim tuav yog yuav tsum tau.
MDI prepolymers feem ntau muaj 15% mus rau 30% NCO. Vim yog cov ntsiab lus nyuaj dua, lawv feem ntau pom cov viscosity siab dua li TDI-raws li cov tshuab. Txawm li cas los xij, lawv muab cov khoom zoo tshaj plaws tom qab kho.
TDI prepolymers feem ntau qhia cov tshuaj tiv thaiv ntau dua thiab lub sij hawm gel luv dua thaum ua. Lawv cov viscosity tsawg kuj txhim kho kev sib xyaw thiab kev ua haujlwm casting.
Txawm li cas los xij, TDI -raws li polyurethane elastomers feem ntau xav tau lub sijhawm ntev dua - kho kom ua tiav lawv lub cev zoo.
MDI prepolymers muab kev tswj cov tshuaj tiv thaiv zoo dua thiab txhim kho lub zog sai. Hauv ntau daim ntawv thov elastomer cam khwb cia, MDI systems tuaj yeem ncav cuag feem ntau ntawm lawv cov khoom siv zog kawg hauv lub sijhawm luv luv, pab cov tuam txhab txo cov voj voog ntau lawm thiab txhim kho kev ua haujlwm.