Polyester polyols feem ntau txhais tau tias yog hydroxyl- txiav cov tebchaw uas nws cov saw hlau molecular muaj cov pawg ester rov ua dua, nrog rau tus lej- qhov hnyav molecular feem ntau yog li ntawm 1000 txog 5000 g / mol. Lawv tuaj yeem muab faib ua hom aromatic lossis aliphatic nyob ntawm seb tus qauv muaj cov nplhaib uas muaj ntxhiab. Kev tsim khoom ntawm polyester polyols feem ntau ua raws ob txoj hauv kev: ib qho yog cov txheej txheem esterification-polycondensation, uas polybasic acids (los yog anhydrides / esters) hnov mob nrog polyols; lwm qhov yog lub nplhaib- qhib polymerization ntawm lactone monomers nrog polyols. Kev hloov pauv hauv cov khoom siv raw thiab cov khoom sib txuas ua rau muaj ntau yam ntawm kev ua tau zoo, thiab cov khoom xws li hydroxyl tus nqi, acid tus nqi, noo noo cov ntsiab lus, viscosity, molecular hnyav, ntom thiab xim Performance index tseem tseem ceeb rau kev soj ntsuam zoo thiab tsim nyog.
Hauv kev lag luam polyurethane,polyester ntaubua lub luag haujlwm tseem ceeb hauv kev tsim qauv. Vim lub siab polarity ntawm ester thiab amide pawg nyob rau hauv polyester-raws li polyurethanes, cov ntaub ntawv uas tshwm sim muaj zog cohesive rog, zoo heev adhesion, siab mechanical zog thiab zoo kawg li abrasion kuj. Thoob plaws ntiaj teb, Stepan, Huafon Group thiab COIM sawv cev rau cov neeg muag khoom ua lag luam hauv daim teb no, suav nrog kwv yees li 30% ntawm tag nrho cov khoom lag luam. Tuam Tshoj yog lub lag luam loj tshaj plaws nrog kwv yees li 45% feem, tom qab ntawd Europe ntawm 20% thiab North America ntawm 13%. Ntawm cov khoom lag luam, aliphatic polyester polyols tsim cov ntu loj tshaj plaws nrog kev sib koom ntawm kwv yees li 62%, thaum elastomers yog qhov tseem ceeb tshaj plaws hauv qab daim ntawv thov, sawv cev kwv yees li 36% ntawm tag nrho cov khoom siv.
Raws li txoj cai, aliphatic polyester polyols feem ntau yog tsim los ntawm aliphatic diacids xws li succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid thiab sebacic acid. Cov qib kev lag luam feem ntau yog raws li adipic acid condensed nrog diols lossis triols. Cov khoom no feem ntau tshwm sim li cov khoom siv dawb dawb lossis tsis muaj xim rau cov kua dej daj daj; cov khoom polyesters muaj melting ranges feem ntau ntawm 25 thiab 50℃thiab tsim siab - kua viscosity ib zaug yaj. Nyob rau hauv sib piv, aromatic polyester polyols muaj rigid benzene nplhaib qauv nyob rau hauv lawv cov caj qaum thiab feem ntau synthesized los ntawm phthalic anhydride, isophthalic acid, terephthalic acid los yog trimellitic anhydride. Lub hauv paus rigidity thiab siab dua cohesive zog ntawm chav tsev uas muaj ntxhiab tsw qab muab zoo hydrophobicity thiab zoo heev hydrolysis tsis kam piv nrog purely aliphatic systems.
Kev lag luam ntawm polyester polyols feem ntau yog ua nyob rau hauv batch reactors, nce mus txog theem esterification tom qab polycondensation. Txhawm rau kom ntseeg tau tias hydroxyl-tawm cov polymers, formulations feem ntau siv 10-50% tshaj ntawm polyol. Thaum lub sij hawm esterification, cov tshuaj tiv thaiv ntawm polyacids los yog anhydrides nrog polyols generates oligomeric diesters thiab triesters thaum tsis tu ncua tso dej. Kev tshem tawm cov dej no los ntawm cov cua kub maj mam yog qhov tseem ceeb rau kev tsav cov tshuaj tiv thaiv rau pem hauv ntej, tab sis kev tshem tawm cov dej ntau dhau tuaj yeem ua rau foaming thiab poob ntawm volatile diols, ua rau kub tswj qhov tseem ceeb. Thaum tus nqi ntawm cov dej tshem tawm mus txog qhov theoretical tus nqi thiab cov kua qaub poob qis dua li ntawm 10 mgKOH / g, esterification yog qhov tseem ceeb.
Cov theem polycondensation hauv qab no suav nrog kev loj hlob ntawm cov saw hlau los ntawm ester- pauv cov tshuaj tiv thaiv nyob rau hauv qhov kub thiab txias. Cov theem no tuaj yeem muab faib ua ua ntej-polycondensation thiab zaum kawg polycondensation. Thaum lub sij hawm ua ntej -polycondensation, lub tshuab nqus tsev yog maj mam txo qis kom tswj tau qhov chaw tiv thaiv ib puag ncig, ua kom txo qis cov kua qaub ntxiv thiab tshem tawm cov polyol ntau dhau. Nyob rau theem kawg, ester- sib pauv cov tshuaj tiv thaiv, tso cai rau hydroxyl- txiav oligomers kom nrawm nrawm ntawm qhov hnyav molecular mus txog qhov xav tau viscosity thiab kev ua haujlwm tsis zoo.
Los ntawm cov kev tswj xyuas kom zoo, polyester polyols tau dhau los ua lub hauv paus tsev thaiv ntawm ntau cov ntaub ntawv polyurethane, txhawb cov ntawv thov tseem ceeb hauv elastomers, adhesives, hluavtaws tawv, coatings, siab -kev ua tau zoo hnav- cov khoom tiv thaiv thiab cov khoom siv. Lawv txoj kev loj hlob txuas ntxiv tsav kev nce qib ntawm polyurethane thev naus laus zis thoob plaws ntiaj teb kev lag luam.