Polyurethane nplaum yog reactive adhesives. Qhov no txhais tau hais tias cov khoom no tau siv rau hauv cov substrates raws li kev sib xyaw ntawm cov khoom hnyav molecular thiab siv cov tshuaj tua kab mob los tsim cov polymer, feem ntau sib txuas. Polyurethane yog tsim los ntawm polyaddition polymerization.
Ntawm cov reactive adhesives, polyurethane yog nyob deb ntawm ntau haiv neeg: dej-raws li,Cov kuab tshuaj raws li cov kuab tshuaj tsis muaj ob lub ntsiab lus nplaum.
Polyurethane nplaum qhia tau zoo heevadhesion zoo rau substrate, siab mechanical zog, raws li zoo raws li yooj yooj yim thiab chemical kuj. Vim cov khoom no, polyurethane nplaum yog siv rau ntau yam kev siv.
Rau kev tsim cov urethane adhesives, ib yam nkausaromatic los yog aliphatic diisocyanates rau PU nplaumyog siv, feem ntau yog cov nram qab no hom: kev siv cov aromatic iscyanates yuav txhawb cov tsim ntawm thawj aromatic amines yog hais tias cov reactive adhesive tsis kho tag nrho. Raws li cov amines raug suav tias yog carcinogenic, cov tshuaj yuav tsum tau saib xyuas. Aromatic isocyanates muaj ntau reactive dua li aliphatic hom, thaum aliphatic isocyanates muaj zoo dua UV stability thiab kub stability. Aliphatic diisocyanates nrog tsawg reactivity yog tsuas yog siv nyob rau hauv cov dej-raws li urethane systems thiab ua tau zoo adhesives, xws li hnyav-raws li los yog hnyav-dawb.
