Hydroxyethyl methyl cellulose (HEMC) yog ib qho non-ionic cellulose ether dav siv hauv kev tsim kho, txheej, ceramics, tshuaj, zaub mov thiab lwm yam lag luam. HEMC muaj dej solubility zoo, thickening, dej tuav, film-forming thiab bonding zog, thiab plays lub luag hauj lwm tseem ceeb nyob rau hauv qhuav-mixed mortar, latex xim, detergent thiab lwm yam teb.
1. Cov txheej txheem ntau lawm
1.1 Raw khoom npaj
HEMC feem ntau yog npaj los ntawm cov nroj tsuag ntuj cellulose, methyl chloride (CH₃Cl), ethylene oxide (C₂H₄O), sodium hydroxide (NaOH) thiab lwm yam khoom siv raw.
Cellulose: Ntoo pulp lossis paj rwb pulp feem ntau yog siv los ua cov khoom siv tseem ceeb, uas yuav tsum tau muaj siab purity thiab ob peb impurities los xyuas kom meej cov khoom zoo.
Alkalizer (NaOH): siv los ua kom cellulose thiab txhim kho cov tshuaj tiv thaiv.
Etherifying tus neeg sawv cev (CH₃Cl thiab C₂H₄O): muab cov methyl thiab hydroxyethyl pawg raws li, kom cellulose hloov cov tshuaj tiv thaiv, txhim kho cov dej solubility thiab cov khoom ua haujlwm.
Organic hnyav (xws li isopropanol): siv los yaj cov reactants, tswj cov tshuaj tiv thaiv ib puag ncig thiab txo cov kev mob tshwm sim.
1.2 Kev kho Alkalization
Tom qab cellulose raug crushed, ib tug tsim nyog tus nqi ntawm sodium hydroxide tov yog ntxiv thiab alkalization kev kho mob yog nqa tawm ntawm ib tug tej yam kub thiab siab, uas feem ntau yuav siv sij hawm 30-60 feeb. Lub hom phiaj tseem ceeb ntawm alkalization yog kom nthuav cov cellulose molecular saw thiab txhim kho nws cov reactivity nrog tus neeg sawv cev etherifying. Cov txheej txheem no feem ntau yog ua nyob rau hauv lub kaw reactor nrog nplawm kom ntseeg tau tias cov tshuaj alkali sib npaug nkag mus rau hauv cellulose.
1.3 Cov tshuaj tiv thaiv Etherification
Cov alkalized cellulose reacts nrog methylation thiab hydroxyethylation reagents (CH₃Cl thiab C₂H₄O) nyob rau hauv lub reactor los tsim hydroxyethyl methyl cellulose. Cov kev mob tshwm sim muaj xws li:
Kub: 60-90°C
Siab: 0.5-1.5 MPa
Sijhawm: 2-5 teev
Thaum lub sij hawm cov tshuaj tiv thaiv, cov tshuaj methylation thiab hydroxyethylation tshwm sim ib txhij, kom cov hydroxyl (-OH) ib feem ntawm cellulose hloov los ntawm methyl (-OCH).₃) thiab hydroxyethyl (-OCH₂CH₂OH), yog li hloov nws cov solubility thiab thickening zog. Txhawm rau txhim kho qib ntawm kev hloov pauv (DS thiab MS qhov tseem ceeb), nws yog qhov yuav tsum tau ua kom zoo dua qhov kev txiav txim thiab kev faib ua feem ntawm tus neeg sawv cev etherification ntxiv.
1.4 Neutralization thiab ntxuav
Tom qab cov tshuaj tiv thaiv ua tiav, lub kaw lus tseem muaj cov alkali tsis ua haujlwm, hnyav thiab los ntawm cov khoom lag luam (xws li NaCl). Yog li ntawd, neutralization thiab ntxuav yog yuav tsum tau:
Neutralization: Siv cov kua qaub (xws li acetic acid) los nruab nrab alkali hauv lub cev thiab kho tus nqi pH rau 6-8.
Ntxuav: Siv cov dej kub ntau los yog ethanol aqueous tov kom rov ntxuav cov cellulose kom tshem tawm cov khoom tsis zoo thiab cov khoom los ntawm cov khoom, txo cov ntsiab lus impurity, thiab txhim kho cov purity ntawm cov khoom.
1.5 Qhuav thiab crushing
Tom qab ntxuav, HEMC tseem muaj cov dej noo siab thiab xav tau kom qhuav. Cov txheej txheem ziab kom qhuav yog:
Airflow drying: siv cov cua kub ceev kom qhuav ntub HEMC, nrog kev ua haujlwm siab thiab tsim nyog rau cov khoom loj.
Lub tshuab nqus tsev ziab: cua sov thiab ziab hauv qhov chaw tsis tshua muaj siab, uas tuaj yeem tiv thaiv cellulose degradation zoo thiab tsim nyog rau cov khoom zoo.
Tom qab ziab, HEMC yog crushed los ntawm pulverizer thiab cov particle loj yog tswj los ntawm kev tshuaj ntsuam kom ua tiav qhov yuav tsum tau fineness ntawm cov khoom (feem ntau 80-120 mesh).
2. Kev tswj xyuas zoo
HEMC kev tswj kom zoo feem ntau suav nrog cov ntsuas hauv qab no:
Degree ntawm kev hloov pauv (DS thiab MS): txiav txim siab qhov solubility thiab viscosity, feem ntau DS yog nyob nruab nrab ntawm 1.1-2.0 thiab MS yog nyob nruab nrab ntawm 0.1-0.5.
Cov ntsiab lus noo noo: feem ntau yuav tsum tau≤5%.
Viscosity: cov qib viscosity sib txawv yuav tsum muaj rau cov ntawv thov sib txawv (xws li 400-100,000 mPa·s).
Purity: yuav tsum muaj cov hmoov tshauv tsawg, tshem tawm cov kuab tshuaj residual, thiab xyuas kom tsis muaj ntxhiab tsw.
3. Cov chaw thov tseem ceeb
Cov khoom siv hauv tsev: siv hauv cov cement mortar, putty hmoov, pobzeb nplaum, los txhim kho cov dej tuav thiab kev tsim kho.
Txheej kev lag luam: siv rau hauv cov xim latex thiab xim, los muab kev zoo rheology thiab kev ua haujlwm los tiv thaiv sagging.
Tshuaj thiab zaub mov: raws li ib tug thickener thiab emulsifier, nyob rau hauv txoj kab nrog zaub mov qib los yog pharmacopoeia qauv.
CovHEMC Cov txheej txheem ntau lawm suav nrog alkalization, etherification, neutralization, ntxuav, ziab thiab crushing. Txhim kho cov txheej txheem tsis zoo thiab txhim kho kev hloov pauv qib thiab cov khoom siv purity yog cov yuam sij rau kev txhim kho HEMC kev ua tau zoo. Nrog rau kev nce ntxiv rau kev tiv thaiv ib puag ncig thiab kev tsim ntsuab, HEMC ntau lawm yuav tau them nyiaj ntau rau kev txuag hluav taws xob thiab txo qis emissions thiab kev siv cov kuab tshuaj ntsuab yav tom ntej.
Post lub sij hawm: May-08-2025