Hydroxyethyl cellulose (HEC) yog non-ionic cellulose ether dav siv hauv kev tsim kho, txheej, roj av, tshuaj txhua hnub thiab lwm yam haujlwm. Nws muaj cov thickening zoo, ncua kev kawm ntawv, dispersion, emulsification, film-forming, tiv thaiv colloid thiab lwm yam khoom, thiab yog ib qho tseem ceeb thickener thiab stabilizer.
1. Kev npaj cov khoom siv raw
Lub ntsiab raw khoom ntawm hydroxyethyl cellulose yog ntuj cellulose. Cellulose feem ntau yog muab rho tawm los ntawm ntoo, paj rwb lossis lwm yam nroj tsuag. Cov txheej txheem rho tawm ntawm cellulose yog qhov yooj yim, tab sis nws yuav tsum muaj siab purity los xyuas kom meej qhov ua tau zoo ntawm cov khoom kawg. Vim li no, chemical lossis mechanical method feem ntau yog siv los kho cov cellulose ua ntej, suav nrog defatting, de-impurity, bleaching thiab lwm cov kauj ruam kom tshem tawm impurities thiab tsis-cellulose Cheebtsam.
2. Kev kho alkalization
Kev kho alkalization yog ib kauj ruam tseem ceeb hauv kev tsim cov hydroxyethyl cellulose. Lub hom phiaj ntawm cov kauj ruam no yog txhawm rau qhib cov pab pawg hydroxyl (-OH) ntawm cov saw cellulose molecular los pab txhawb cov tshuaj tiv thaiv etherification tom ntej. Sodium hydroxide (NaOH) tshuaj feem ntau yog siv los ua tus neeg sawv cev alkalizing. Cov txheej txheem tshwj xeeb yog: sib tov cellulose nrog sodium hydroxide tov kom swell thiab disperse cellulose nyob rau hauv alkaline tej yam kev mob. Lub sijhawm no, pawg hydroxyl ntawm cov cellulose molecules ua haujlwm ntau dua, npaj rau cov tshuaj tiv thaiv etherification tom ntej.
3. Cov tshuaj tiv thaiv Etherification
Etherification cov tshuaj tiv thaiv yog cov kauj ruam tseem ceeb hauv kev tsim cov hydroxyethyl cellulose. Cov txheej txheem no yog ua kom paub cov ethylene oxide (tseem hu ua ethylene oxide) rau cellulose tom qab kev kho alkalinization, thiab hnov mob nrog hydroxyl pawg hauv cellulose molecules los tsim hydroxyethyl cellulose. Cov tshuaj tiv thaiv feem ntau yog ua nyob rau hauv lub kaw reactor, cov tshuaj tiv thaiv kub yog feem ntau tswj ntawm 50-100 ° C, thiab cov tshuaj tiv thaiv lub sij hawm yog li ntawm ob peb teev mus rau ntau tshaj kaum teev. Cov khoom kawg ntawm cov tshuaj tiv thaiv yog ib feem ntawm hydroxyethylated cellulose ether.
4. Neutralization thiab ntxuav
Tom qab cov tshuaj tiv thaiv etherification tiav lawm, cov reactants feem ntau muaj ib tug loj npaum li cas ntawm unreacted alkali thiab by-products. Txhawm rau kom tau txais cov khoom lag luam ntshiab hydroxyethyl cellulose, kev ua haujlwm nruab nrab thiab kev ntxuav yuav tsum tau ua. Feem ntau, dilute acid (xws li dilute hydrochloric acid) yog siv los ua kom tsis muaj cov alkali seem hauv cov tshuaj tiv thaiv, thiab tom qab ntawd cov reactants rov qab ntxuav nrog ntau cov dej kom tshem tawm cov dej-soluble impurities thiab cov khoom lag luam. Cov tshuaj ntxuav hydroxyethyl cellulose muaj nyob rau hauv daim ntawv ntawm lub ncuav mog qab zib ntub dej.
5. Lub cev qhuav dej thiab ziab
Lub ncuav mog qab zib ntub dej tom qab ntxuav muaj cov dej ntau thiab yuav tsum tau lub cev qhuav dej thiab ziab kom tau cov hmoov hydroxyethyl cellulose khoom. Lub cev qhuav dej feem ntau yog ua los ntawm lub tshuab nqus tsev los yog kev sib cais centrifugal kom tshem tawm cov dej feem ntau. Tom qab ntawd, lub ncuav mog qab zib ntub yog xa mus rau cov khoom siv ziab kom qhuav. Cov khoom siv ziab khaub ncaws feem ntau suav nrog lub tshuab ziab khaub ncaws, lub tshuab ziab khaub ncaws thiab cov tshuab ziab khaub ncaws. Kev ziab kom qhuav yog feem ntau tswj ntawm 60-120 ℃ los tiv thaiv kub dhau los ntawm kev ua rau cov khoom tsis zoo lossis kev ua haujlwm tsis zoo.
6. Sib tsoo thiab tshuaj ntsuam
Cov qhuav hydroxyethyl cellulose feem ntau yog ib qho loj thaiv lossis cov khoom siv granular. Txhawm rau kom yooj yim rau kev siv thiab txhim kho cov dispersibility ntawm cov khoom, nws yuav tsum tau ua hauv av thiab tshuaj ntsuam xyuas. Kev sib tsoo feem ntau yog siv lub tshuab sib tsoo kom zom cov khoom loj hauv cov hmoov zoo. Kev tshuaj ntsuam yog cais cov coarse hais tias tsis ncav cuag qhov yuav tsum tau particle loj nyob rau hauv cov hmoov zoo los ntawm cov ntxaij vab tshaus nrog txawv apertures los xyuas kom meej lub uniform fineness ntawm cov khoom kawg.
7. Cov khoom ntim thiab khaws cia
Cov khoom siv hydroxyethyl cellulose tom qab kev sib tsoo thiab kev tshuaj ntsuam xyuas muaj qee yam fluidity thiab dispersibility, uas yog haum rau kev thov ncaj qha los yog ua ntxiv. Cov khoom kawg yuav tsum tau ntim thiab khaws cia kom tsis txhob ya raws, paug lossis oxidation thaum thauj thiab khaws cia. Cov ntaub ntawv pov thawj noo noo thiab tiv thaiv oxidation xws li cov hnab ntawv txhuas lossis cov hnab ntim ntau txheej feem ntau yog siv rau ntim. Tom qab ntim khoom, cov khoom yuav tsum tau muab cia rau hauv qhov chaw txias thiab qhuav, tsis txhob raug tshav ntuj ncaj qha thiab qhov kub thiab txias thiab cov av noo siab kom ntseeg tau tias nws ua haujlwm ruaj khov.
Kev tsim cov txheej txheem ntawm hydroxyethyl cellulose feem ntau suav nrog kev npaj cov khoom siv raw, kev kho alkalization, cov tshuaj tiv thaiv etherification, nruab nrab thiab ntxuav, lub cev qhuav dej thiab ziab, sib tsoo thiab tshuaj ntsuam xyuas, thiab cov khoom ntim khoom zaum kawg. Txhua kauj ruam muaj nws tus kheej cov txheej txheem tshwj xeeb thiab cov ntsiab lus tswj. Cov tshuaj tiv thaiv kab mob thiab kev ua haujlwm tshwj xeeb yuav tsum tau tswj xyuas nruj me ntsis thaum lub sijhawm tsim khoom los xyuas kom meej qhov ua tau zoo thiab ruaj khov ntawm cov khoom. Cov khoom siv polymer no muaj ntau yam kev siv hauv kev tsim khoom thiab kev ua neej nyob txhua hnub, qhia txog nws qhov tseem ceeb uas tsis tuaj yeem hloov pauv.
Post lub sij hawm: Aug-21-2024