Thawj daim ntawv thov kev lag luam ntawm polyurethanes tau tsim nyob rau hauv nruab nrab -20th caug xyoo. Txij thaum ntawd los, lawv cov kev siv tau nce hauv kev lag luam xws li kev tsim kho, tsheb, tub yees, rooj tog thiab khau. Polyurethanes yog cov khoom siv ntau yam thiab tuaj yeem pom muaj nyob hauv ntau yam khoom txhua hnub nyob ib puag ncig peb.
Rigid polyurethane (PUR)thiab polyisocyanurate (PIR) rwb thaiv tsev cov khoom siv tau zoo heev, lub teeb yuag, thiab muaj peev xwm ua raws li cov ntaub ntawv feem ntau. Lawv zoo heev thermal conductivity thiab siab zog-rau-qhov hnyav piv, ua ke nrog zoo heev manufacturing versatility, muaj ntau yam khoom.
Yog li ntawd, PIR thiab PUR rwb thaiv tsev cov khoom yog lub ntuj xaiv rau feem ntau cov tsev rwb thaiv tsev daim ntaub ntawv.
Rigid PUR rwb thaiv tsev cov khoom yog tsim los ntawm reacting ib tug kua polyol tivthaiv nrog ib tug kua polymeric isocyanate tivthaiv, diphenylmethane diisocyanate (MDI), nyob rau hauv lub xub ntiag ntawm ib tug tshuab ntxhua khaub ncaws thiab lwm yam additives. Cov khoom sib xyaw ua ke tom qab ntawd ua rau exothermically los ua ib qho nyuaj thermosetting polymer, thiab raws li tus neeg sawv cev tshuab evaporates thaum lub sij hawm exothermic cov tshuaj tiv thaiv, ib tug kaw-cell, low-density rigid rwb thaiv tsev khoom yog tsim. Kev rwb thaiv tsev zoo heev yog ua tiav vim qhov tsis tshua muaj thermal conductivity ntawm cov gases daig nyob rau hauv lub kaw-cell qauv thiab tsawg tshav kub conduction los ntawm cov khoom pore phab ntsa vim qhov tsawg ntom, nrog rau kwv yees li 97% ntawm cov npuas ntim tau daig gases.
Rigid PIR txawv ntawm PUR nyob rau hauv uas nws yog tsim los siv ntau tshaj ntawm MDI tivthaiv. Nyob rau hauv lub xub ntiag ntawm ib tug tsim nyog catalyst, ntau tshaj MDI reacts nrog nws tus kheej los tsim ib tug isocyanurate, uas yog yus muaj los ntawm kev nce thermal stability. PIR rwb thaiv tsev cov khoom ua rau pom kev ua tau zoo hluav taws ntau dua, qis qis thiab kev ua haujlwm kub siab dua li PUR thiab, thaum muab tso rau hauv cov khoom siv hauv tsev, tuaj yeem ua tau raws li qee qhov kev xav tau hluav taws kub, xws li cov tam sim no hais los ntawm kev tuav pov hwm kev lag luam rau qee yam kev siv. .
Yog xav paub ntxiv txog cov khoom rwb thaiv tsev, thov hu rau peb.