Polyurethane prepolymer yog dab tsi?
Polyurethane prepolymer yog qhov tseem ceeb nruab nrab hauv kev tsim cov khoom siv polyurethane. Nws yog tsim los ntawm cov tshuaj tiv thaiv ntawm ib qho isocyanate thiab polyol. Cov tshuaj tiv thaiv ntawm ob yam khoom no tsim ib qho chaw hu ua prepolymer, uas feem ntau muaj cov pab pawg isocyanate. Qhov no prepolymer ua haujlwm ua lub tsev thaiv rau cov khoom siv polyurethane kawg.
Lub synthesis ntawm polyurethane muaj ob yam tseem ceeb:
1. Isocyanates: Cov no yog cov tshuaj reactive heev uas muaj cov isocyanate functional pawg (-NCO). Cov isocyanates muaj xws li toluene diisocyanate (TDI) thiab methylene diphenyl diisocyanate (MDI).
2. Polyols: Cov no yog cov sib txuas nrog ntau pawg hydroxyl (-OH). Polyols tuaj yeem muab tau los ntawm ntau qhov chaw thiab tej zaum yuav muaj qhov sib txawv molecular hnyav. Cov polyols muaj xws li polyester polyols, polyether polyols, thiab tshwj xeeb polyols.
Cov tshuaj tiv thaiv ntawm isocyanates thiab polyols ua rau muaj kev sib txuas ntawm urethane, ua rau kev tsim cov polyurethane. Thaum cov tshuaj tiv thaiv ua tib zoo tswj, thiab siv ntau tshaj ntawm isocyanate, lub prepolymer yog tsim. Lub prepolymer feem ntau muaj cov pab pawg isocyanate uas tsis muaj kev cuam tshuam.
Polyurethane, muab tau los ntawm prepolymers, pom cov ntawv thov hauv ntau qhov kev lag luam, suav nrog kev tsim kho, tsheb, rooj tog zaum, txheej, nplaum, sealants, thiab lwm yam. Lub versatility ntawm polyurethane tshwm sim los ntawm lub peev xwm los kho cov tshuaj muaj pes tsawg leeg thiab tswj qhov piv ntawm isocyanate rau polyol, uas ua rau cov ntaub ntawv nrog txawv zog xws li yooj, hardness, thiab resilience.
Dab tsi yog cov ntawv thov ntawm polyurethane prepolymer?
Dab tsi yog polyurethane prepolymer siv rau?
1. Prepolymers yog siv los tsim cov khoom siv tau yooj yim lossis nruj polyurethane foams. Cov foams no pom cov ntawv thov hauv txaj, cushions, cov ntaub ntawv rwb thaiv tsev, thiab ntim khoom.
2. Polyurethane prepolymers yog ua haujlwm nyob rau hauv kev tsim cov txheej thiab sealants. Cov txheej txheem no muab cov txheej txheem tiv thaiv ntawm qhov chaw, xws li hlau, ntoo, lossis pob zeb, muab cov kav ntev thiab tsis kam hnav, tshuaj lom neeg, thiab huab cua.
3. Prepolymers yog siv nyob rau hauv kev tsim cov polyurethane adhesives, uas yog lub npe hu rau lawv muaj zog sib raug zoo peev xwm nyob rau hauv ntau yam substrates.
4. Polyurethane elastomers, nrog rau cov log, cov menyuam, thiab ntau yam molded qhov chaw, yog tsim los ntawm prepolymers. Cov elastomers no ua rau pom kev puas tsuaj zoo heev thiab yoog raws.
5. Polyurethane prepolymer yog siv rau hauv cov txheej txheem casting thiab molding los tsim ntau yam khoom, xws li cov khoom siv tsheb, cov khoom siv, thiab cov qauv.
6. Hauv kev tsim cov khau khau thiab cov khoom siv, polyurethane prepolymers feem ntau yog siv los ua kom tiav cov khoom tsim nyog xws li yoog raws, kev poob siab, thiab ua haujlwm ntev.