Hydroxyethyl cellulose (HEC) yog tsis-ionic, dej-soluble polymer muab tau los ntawm cellulose, lub ntuj polymer pom nyob hauv cov phab ntsa ntawm tes ntawm cov nroj tsuag. Nws yog dav siv nyob rau hauv ntau yam kev lag luam, suav nrog cov tshuaj, tshuaj pleev ib ce, pleev xim, thiab cov nplaum, vim nws cov khoom siv ua kom zoo nkauj, ua yeeb yaj kiab. Kev npaj ntawm hydroxyethyl cellulose cuam tshuam nrog lub etherification ntawm cov cellulose nrog ethylene oxide nyob rau hauv alkaline tej yam kev mob. Tus txheej txheem no tuaj yeem tawg rau hauv ob peb kauj ruam tseem ceeb: kev ua kom huv huv, alkalization, etheralization, ntxuav, ntxuav, thiab kom qhuav.
1. Kev ua kom huv huv
Thawj kauj ruam hauv kev npaj ntawm hydroxyethyl cellulose yog qhov huv ntawm cellulose, feem ntau yog los ntawm ntoo pulp lossis cov paj rwb. Cellulose nyoos muaj cov impurities xws li lignin, hemicellulose, thiab lwm yam kev rho tawm uas yuav tsum tau muab tshem tawm kom tau txais kev hloov siab dawb huv rau kev hloov kho cov tshuaj lom neeg.
Cov kauj ruam koom nrog:
Kev Ua Txhua Yam: Cov nqaij nyoos yog cov txheej txheem sib xyaw kom txo nws cov loj thiab nce nws thaj chaw thaj chaw, ua kom yooj yim rau cov tshuaj lom neeg.
Tshuaj lom neeg tshuaj lom neeg: Lub cellulose kho nrog cov socium hydroxide (NAsoh) thiab sodium sulfite (NA2OHO3)) Cellulose cellulose.
2. Alkalization
Lub cellulose huv yog tom qab ntawd alkalized los qhib nws rau lub here cov tshuaj tiv thaiv. Qhov no cuam tshuam nrog kho lub cellulose nrog cov tshuaj aqueous ntawm sodium hydroxide.
Cov tshuaj tiv thaiv:
Cellulose + Naoh → alkali cellulose
Tus txheej txheem:
Lub cellulose raug tshem tawm hauv dej, thiab sodium hydroxide kev daws tau ntxiv. Cov concentration ntawm Naoh feem ntau yog li ntawm 10-30%, thiab cov tshuaj tiv thaiv yog nqa tawm ntawm qhov kub ntawm 20-40 ° C.
Qhov sib tov tau muab do kom ntseeg tau cov kev nqus cov kev nqus ntawm lub alkali, ua rau kev tsim cov alkali cellulose. Qhov nruab nrab no yog ntau dua los ntawm ethylene oxide, muab cov txheej txheem ntawm etherification.
3. Tsib Nrab
Cov kauj ruam tseem ceeb hauv kev npaj ntawm hydroxyethyl cellulose yog etherification ntawm alkali cellulose nrog ethylene oxide. Qhov yeeb yam no qhia txog cov pab pawg hydroxyethyl (-ch2ch2oh) rau hauv lub cellulose cellebone, ua rau nws dej-soluble.
Cov tshuaj tiv thaiv:
Alkali Cellulose + Ethylene Oxide → Hydroxyethyl cellulose + Naoh
Tus txheej txheem:
Ethylene oxide yog ntxiv rau lub alkali cellulose, txawm nyob rau hauv ib tug batch lossis txuas ntxiv cov txheej txheem. Cov tshuaj tiv thaiv yog ib txwm ua nyob rau hauv ib tug autoclave lossis siab reactor.
Cov tshuaj tiv thaiv, suav nrog kub (50-100 ° C) thiab siab (1-5 fon), yog ua tib zoo tswj tau hloov cov pab pawg hydroxyethyl. Cov qib degree hloov pauv (DS) thiab cov hniav nyiaj hniav mob (MS) yog qhov tsis muaj tseeb uas cuam tshuam cov khoom ntawm cov khoom kawg.
4. Neutralization
Tom qab lub Ehereification cov tshuaj tiv thaiv, qhov sib xyaw muaj hydroxyethyl cellulose thiab seem sodium hydrocide. Cov kauj ruam tom ntej yog kev ntxhov siab, qhov ntau tshaj alkali yog neutralized siv cov kua qaub, feem ntau acetich acid (ch3cooh) lossis hydrochloric acid (hcl).
Cov tshuaj tiv thaiv: Naoh + hc → nacl + h2o
Tus txheej txheem:
Cov kua qaub yog maj mam ntxiv rau cov tshuaj tiv thaiv sib xyaw ua ke kom tsis txhob muaj cua sov ntau thiab tiv thaiv kev ua kom muaj zog ntau thiab tiv thaiv cellulose.
Qhov kev sib xyaw ntawm nruab nrab yog tom qab ntawd raug kho kom ntseeg tau tias nws yog nyob rau hauv ntau yam, ib txwm nyob hauv nruab nrab pH (6-8).
5. Ntxuav
Tom qab kev neutralization, cov khoom yuav tsum tau muab ntxuav kom tshem cov ntsev thiab lwm yam khoom. Cov kauj ruam no yog qhov tseem ceeb rau tau txais hydroxyethyl cellulose.
Tus txheej txheem:
Cov tshuaj tiv thaiv yog diluted nrog dej, thiab hydroxyethyl cellulose yog sib cais los ntawm kev lim lossis centrifugation.
Qhov sib cais hydroxyethyl cellulose yog rov qab ntxuav nrog cov dej deionized kom tshem tawm cov ntsev uas cov neeg tsis txaus ntseeg thiab tsis zoo. Cov txheej txheem ntxuav txuas ntxiv kom txog thaum txoj kev ntxuav dej nce mus txog ib qho kev ua haujlwm tshwj xeeb, qhia txog kev tshem tawm ntawm soluble impurities.
6. Kom qhuav
Kauj ruam kawg hauv kev npaj ntawm hydroxyethyl cellulose yog kom qhuav. Kauj ruam no tshem tawm cov dej ntau dhau, yielding ib qhuav cov khoom qhuav, hmoov zoo tsim nyog rau ntau yam kev siv.
Tus txheej txheem:
Ntxuav hydroxyethyl cellulose yog kis rau kom qhuav cov tais lossis xa tawm los ntawm lub qhov ziab. Qhov ziab kom qhuav yog ua tib zoo tswj kom tsis txhob thermal degradation, feem ntau tau xws li ntawm 50-80 ° C.
Hloov pauv, tshuaj tsuag kom qhuav tuaj yeem siv rau nrawm thiab ua kom qhuav. Nyob rau hauv txau kom qhuav, lub aqueous hydroxyethyl cellulose tov yog atomized rau hauv cov dej ntws zoo thiab qhuav hauv cov dej kub, ua rau hmoov zoo.
Cov khoom qhuav yog li milled rau qhov xav tau qhov loj me thiab ntim rau kev cia khoom thiab xa tawm.
Tswjhwm Zoo thiab Kev Siv
Thoob plaws hauv kev npaj cov txheej txheem, nyuaj tswj kev ntsuas ntsuas tau ua tiav los ua kom muaj kev sib xws thiab zoo ntawm hydroxyethyl cellulose. Cov ntsiab lus tseem ceeb xws li viscosity, degree hloov chaw, noo noo cov ntsiab lus, thiab qhov loj me saib xyuas tau saib xyuas tsis tu ncua.
Cov Ntawv Thov:
Kws Tshuaj Kho Mob: Siv los ua tus neeg sawv cev tuab, binder, thiab stabilizer nyob rau hauv cov qauv xws li ntsiav tshuaj, raug rau cov raug tshem tawm, thiab tshuaj pleev.
Cov tshuaj pleev ib ce: muab cov viscosity thiab kev ntxhib los mos rau cov tshuaj pleev li cream, tshuaj ntau, thiab tshuaj zawv plaub hau.
Xim thiab pleev xim: ua raws li cov tuab tuab thiab rheology kho kom zoo, txhim kho cov khoom thov thiab kev ruaj ntseg ntawm cov xim tha xim.
Kev Lag Luam Khoom Noj: Ua haujlwm raws li cov tuab tuab, stabilizer, thiab emulsifier hauv ntau yam khoom noj.
Kev npaj ntawm hydroxyethyl cellulose cuam tshuam nrog cov tshuaj txhais tau zoo thiab kho tshuab kom pom cov pab pawg hydroxyethyl pawg. Txhua kauj ruam, los ntawm cellulose ua kom huv huv kom qhuav, yog qhov tseem ceeb hauv kev txiav txim siab qhov zoo thiab ua haujlwm ntawm cov khoom kawg. Hydroxyethyl cellulose cov khoom muaj ntau yam ntxiv rau ntau yam kev lag luam, qhia txog qhov tseem ceeb ntawm kev xav tau tshwj xeeb ntawm kev siv ntau yam.
Lub Sijhawm Post: Lub Tsib Hlis-28-2024