Iyini i-polyurethane ene-Moisture-cured

Iyini i-polyurethane ene-Moisture-cured

Umswakama owenziwe nge-polyurethane iyingxenye eyodwa ye-polyurethane ukuthi ikhambi layo liwumswakama wemvelo ekuqaleni. I-polyurethane elapheka ngokuswakama ngokuyinhloko iqukethe i-pre-polymer enqanyuliwe isocyanate. Izinhlobo ezahlukahlukene ze-pre-polymer zingasetshenziswa ukuhlinzeka ngempahla edingekayo. Isibonelo, ama-polyether polyether polyols aphethwe yi-isocyanate asetshenziselwa ukunikeza ukuguquguquka okuhle ngenxa yezinga lokushisa eliphansi lokushintsha kwengilazi. Ukuhlanganisa ingxenye ethambile, njenge-polyether, nengxenye eqinile, njenge-polyurea, inikeza ubulukhuni obuhle nokuguquguquka kwezingubo. Ngaphezu kwalokho, izakhiwo nazo zilawulwa ngokukhetha izinhlobo ze-isocyanate ukuze zihlanganiswe ne-pre-polymer.

Izinhlobo ezimbili eziyinhloko zama-isocyanate yi-isocyanate enamakha ne-aliphatic isocyanate. I-isocyanate ephunga inokuphinda isebenze kabusha. Kodwa-ke, inokuqina okubuthakathaka kwangaphandle kanye nokushintsha kombala okunzima. Ezinye izibonelo zama-isocyanate anuka kamnandi yi-toluene diisocyanate(TDI) kanye ne-4,4'diphenylmethane diisocyanate(MDI). Ngakolunye uhlangothi, i-aliphatic isocyanate, njenge-isophorone diisocyanate (IPDI), inikeza isimo sezulu esihle kakhulu futhi umbala ukugcinwa; nokho, ukusebenza kabusha kwe-aliphatic isocyanate kuphansi, ngakho-ke amanye ama-catalyst angadingeka. Ngakho-ke, izinhlobo ze-isocyanate zibalulekile ukuze kuzuzwe impahla efiselekayo. Ngaphezu kwalokho, izithasiselo, izincibilikisi, izingulube, njll. zinganezelwa ngokusekelwe ekusetshenzisweni. Kodwa-ke, izinto ezisetshenziswayo zama-polyurethanes alaphe umswakama kumele zilawulwe ukuze zingabi nomswakama ukuze kutholwe ukugcinwa okuhle kokuzinza kanye nempahla yefilimu.

Enye inzuzo ye i-polyurethane ekwazi ukumelana nomswakama ukuthi kuyingxenye eyodwa. Ngakho-ke, kulula ukuyisebenzisa njengoba kungekho isilinganiso esifanele sokuxuba esidingekayo, uma kuqhathaniswa nezingubo ezimbili zezingxenye. I-PU ephulukiswe umswakama ixhunyaniswe nokusabela kwe-pre-polymer enqanyuliwe i-Isocyanate namanzi emoyeni, ikhiqiza ama-amine kanye nenani elincane le-carbon dioxide. Ekugcineni, ukusabela kwama-amine kanye nayo yonke enye i-pre-polymer enqanyuliwe isocyanate kwenzeka, okwakha ukuxhumana kwe-urea.