Yintoni i-polyurethane enyangwa ngokufuma

Yintoni i-polyurethane enyangwa ngokufuma

I-polyurethane ehlanjululwe ngokufuma yinxalenye enye ye-polyurethane ukuba unyango lwayo luqala ukufuma kokusingqongileyo. I-polyurethane enyangekayo yokufuma ibandakanya ikakhulu i-isocyanate-terinated pre-polymer. Iindidi ezahlukeneyo ze-pre-polymer zingasetyenziselwa ukubonelela ngepropati efunekayo. Ngokomzekelo, ii-polyether polyether polyols ze-isocyanate zisetyenziselwa ukubonelela ukuguquguquka okulungileyo ngenxa yokushisa kweglasi ephantsi yokutshintsha. Ukudibanisa icandelo elithambileyo, elifana ne-polyether, kunye necandelo elinzima, njenge-polyurea, linika ubunzima obuhle kunye nokuguquguquka kweengubo. Ngaphezu koko, iipropathi zikwalawulwa ngokukhetha iintlobo ze-isocyanates ukudibanisa ne-pre-polymer.

Iindidi ezimbini eziphambili ze-isocyanates yi-aromatic isocyanate kunye ne-aliphatic isocyanate. I-isocyanate enuka kamnandi inokuphinda isebenze. Nangona kunjalo, inokuqina okulambathayo kwangaphandle kunye nokuguquka kombala okunzima. Eminye imizekelo ye-isocyanates enuka kamnandi yi-toluene diisocyanate(TDI) kunye ne-4,4'diphenylmethane diisocyanate(MDI). Kwelinye icala, i-aliphatic isocyanate, efana ne-isophorone diisocyanate (IPDI), ibonelela ngemozulu entle kakhulu kwaye umbala ugcino nangona kunjalo, ukusebenza kwakhona kwe-aliphatic isocyanate kuphantsi, ngoko ke ezinye ii-catalysts zinokufuneka. Ngoko ke, iintlobo ze-isocyanate zibalulekile ukufezekisa ipropati enqwenelekayo. Ngapha koko, izongezelelo, izinyibilikisi, ii-pigments, njl.njl. zingongezwa ngokusekelwe kwisicelo. Nangona kunjalo, imathiriyeli ekrwada ye-polyurethanes enyangelwe ngumswakama kufuneka ilawulwe ukuba ingabi namanzi ukuze kufumaneke uzinzo olufanelekileyo lokugcina kunye nepropathi yefilimu.

Enye inzuzo ye i-polyurethane enyangekayo yokufuma kukuba licandelo elinye. Ngoko ke, kulula ukuyisebenzisa kuba akukho mfuneko yokuxuba okufanelekileyo, xa kuthelekiswa neengubo zamacandelo amabini. I-PU ehlanjululwe ngumswakama i-crosslinked ngokuphendula kwe-Isocyanate-terinated pre-polymer kunye namanzi emoyeni, ukuvelisa i-amines kunye nexabiso elincinci le-carbon dioxide. Okokugqibela, ukusabela kwee-amines kunye nayo yonke i-isocyanate-terinated pre-polymer yenzeka, eyenza unxibelelwano lwe-urea.