Txoj kev npaj ntawm polyester polyols

Kev npaj ntawm polyester polyols txais yuav ib txoj kev sib tshuam.
Hauv thawj theem, polyols (ethylene glycol, propylene glycol, diethylene glycol, trimethylolpropane, pentaerythritol, 1, 4-}butanediol, thiab lwm yam) raug rau esterification thiab condensation tshua nrog binary acids (phthalic acid, adipic acid, halogenated. phthalic acid, thiab lwm yam) los yog anhydrides (phthalic anhydride, thiab lwm yam) ntawm 140-200 degree . Qhov kub siab tshaj plaws ntawm cov fractionator yog tswj ntawm 100-102 degree . Tom qab tshem tawm feem ntau ntawm cov khoom tsim los ntawm cov dej hauv qab atmospheric siab, nws tau khaws cia ntawm 200-230 degree rau 1-2 teev, Lub sijhawm no, cov kua qaub feem ntau poob rau 20-30mg KOH/g.
Qhov thib ob theem yog nqus thiab maj mam nce lub nqus tsev kawm ntawv kom tshem tawm cov kab dej thiab cov glycol ntau dhau los ntawm kev txo qis, tso cai rau cov tshuaj tiv thaiv mus rau qhov kev taw qhia ntawm kev tsim cov kua qaub qis polyester polyols, uas tuaj yeem hu ua "nqus melting method. ". Inert gases xws li nitrogen tseem tuaj yeem txuas ntxiv mus nqa dej, hu ua "carrier gas melting method". Xwb, azeotropic cov kuab tshuaj xws li toluene tuaj yeem muab ntxiv rau hauv cov tshuaj tiv thaiv, thiab cov dej ua tau maj mam nqa tawm los ntawm cov dej sib cais thaum lub sij hawm toluene reflux. Txoj kev no hu ua "azeotropic distillation".
Vim muaj ntau hom lossis txheej txheem kev npaj, ntau hom polyester polyols muaj cov khoom sib txawv. Cov ntsuas tseem ceeb rau polyester polyols yog hydroxyl tus nqi, acid tus nqi, noo noo, viscosity, molecular hnyav, ntom, thiab chromaticity.