Mene ne Danshi-warkar da polyurethane

Mene ne Danshi-warkar da polyurethane

Danshi-warkar da polyurethane polyurethane kashi ɗaya ne wanda maganin sa shine farkon danshin muhalli. Dashi-curable polyurethane yafi kunshi na isocyyanate-kare pre-polymer. Ana iya amfani da nau'ikan pre-polymer iri-iri don samar da kadarorin da ake buƙata. Misali, ana amfani da polyether polyols da aka ƙare isocyyanate don samar da sassauci mai kyau saboda ƙarancin canjin gilashin su. Haɗuwa da sassauƙa mai laushi, irin su polyether, da yanki mai wuyar gaske, irin su polyurea, yana ba da tauri mai kyau da sassauci na sutura. Haka kuma, ana sarrafa kaddarorin ta hanyar zaɓar nau'ikan isocyanates don haɗawa da pre-polymer.

Manyan nau'ikan isocyanates guda biyu sune isocyanate aromatic da aliphatic isocyanate. Aromatic isocyanate yana da babban reactivity. Duk da haka, yana da ƙarancin ƙarfin waje da kuma rashin launi mai tsanani. Wasu misalan isocyanates aromatic sune toluene diisocyanate (TDI) da 4,4'diphenylmethane diisocyanate (MDI). A gefe guda, aliphatic isocyanate, irin su, isophorone diisocyanate (IPDI), yana ba da kyakkyawan yanayi da yanayi. launi riƙewa; duk da haka, reactivity na aliphatic isocyanate yana da ƙasa, don haka ana iya buƙatar wasu abubuwan haɓakawa. Sabili da haka, nau'ikan isocyanate suna da mahimmanci don cimma abubuwan da ake so. Bugu da ƙari kuma, za a iya ƙara abubuwan ƙarawa, kaushi, pigments, da sauransu dangane da aikace-aikacen. Duk da haka, dole ne a sarrafa kayan albarkatun kasa don danshi-warkar da polyurethane don zama mai laushi don samun kwanciyar hankali mai kyau da kuma kayan fim.

Da sauran amfanin danshi-curable polyurethane shi ne cewa bangare daya ne. Sabili da haka, yana da sauƙi don amfani tun lokacin da ba'a buƙatar rabo mai dacewa da kyau, idan aka kwatanta da suturar sassa biyu. PU da aka warkar da danshi an haɗa shi ta hanyar amsawar isocyanate- ƙare pre-polymer da ruwa a cikin iska, samar da amines da ƙaramin adadin carbon dioxide. A ƙarshe, amsawar amines da sauran isocyanate-terminated pre-polymer yana faruwa wanda, ya samar da haɗin gwiwar urea.