Focus on Cellulose ethers

Cov txheej txheem tsim khoom ntawm HPMC yog dab tsi

Refined paj rwb - qhib - alkalization - etherification - neutralization - sib cais - ntxuav - cais - ziab - crushing - ntim - tiav HPMC cov khoom qhib: Cov paj rwb refined yog qhib kom tshem tawm cov hlau thiab ces crushed. Pulverized refined paj rwb yog nyob rau hauv daim ntawv ntawm hmoov, nrog ib tug particle loj ntawm 80 mesh thiab ib tug transmittance ntawm 100%. Txwv tsis pub, nws yooj yim rau coalesce ua ke thaum lub sij hawm cov txheej txheem tshuaj tiv thaiv thiab txo cov etherification efficiency.

Alkalization: Ntxiv cov hmoov refined paj rwb tom qab paj rwb qhib rau cov kuab tshuaj inert, thiab qhib nws nrog alkali thiab cov dej mos kom o ntawm lub lattice ntawm refined paj rwb los pab txhawb kev nkag mus ntawm etherification tus neeg sawv cev molecules thiab txhim kho cov uniformity ntawm etherification cov tshuaj tiv thaiv. Cov alkali siv rau alkalization yog hlau hydroxide los yog cov organic alkali. Tus nqi ntawm alkali ntxiv (los ntawm huab hwm coj, tib yam hauv qab no) yog 0.1-0.6 npaug ntawm cov paj rwb refined, tus nqi ntawm cov dej mos ntxiv yog 0.3-1.0 npaug ntawm cov paj rwb refined; Cov kuab tshuaj inert yog sib xyaw ntawm cawv thiab hydrocarbon, thiab tus nqi ntawm inert hnyav ntxiv yog 0.3-1.0 npaug ntawm cov paj rwb refined. 7 -15 zaug ntawm qhov ntawd: Cov kuab tshuaj inert kuj tuaj yeem yog cawv nrog 3-5 carbon atoms (xws li cawv, propanol), acetone. Nws tuaj yeem yog aliphatic hydrocarbons thiab muaj ntxhiab hydrocarbons; kub yuav tsum tau tswj nyob rau hauv 0-35 ° C thaum lub sij hawm alkalization; Lub sijhawm alkalization yog li 1 teev. Kev hloov pauv ntawm qhov kub thiab lub sijhawm tuaj yeem txiav txim siab raws li cov khoom siv thiab cov khoom xav tau.

Etherification: Tom qab kev kho alkalization, nyob rau hauv lub tshuab nqus tsev, tus neeg sawv cev etherification yog ntxiv rau etherification, thiab tus neeg sawv cev etherification yog propylene oxide. Txhawm rau txo qis kev noj cov tshuaj etherification, thaum lub sijhawm ua haujlwm etherification, tus neeg sawv cev etherification yog ntxiv rau ob zaug, tus nqi ntawm thawj qhov sib ntxiv yog 1-3.5 npaug ntawm cov paj rwb refined, thiab tag nrho cov nyiaj ntawm ob qhov ntxiv yog 1.5. -4 npaug ntawm cov paj rwb refined. sij hawm. Tom qab ntxiv tus neeg sawv cev etherifying thawj zaug, do ntawm ≤30 ° C rau 45min-90min, tom qab ntawd nce qhov kub ntawm 50-100 ° C rau etherification rau 1-5h, tom qab ntawd txias rau ≤30 ° C, zaum ob ntxiv etherification stirring, stirring lub sij hawm yog 30-120min, thiab ces rhuab mus? ? ? Ua etherification, lub sij hawm yog 1-4h, lub sij hawm no, cov paj rwb refined siab reacts nrog etherification tus neeg sawv cev los tsim hYDROXYPROPYL METHYLCELLULOSE HPMC.

Crushing thiab ntim: crushing thiab sieving cov khoom qhuav ntawm cov khoom tsim tam sim no, qhov loj me ntawm HPMC cov khoom lag luam ntawm cov khoom tsim tam sim no tom qab crushing thiab sieving yog 40 mesh thiab transmittance yog 10096, los yog raws li cov neeg siv xav tau. Tom qab ntawd ntim cov HPMC.


Post lub sij hawm: Nov-24-2022
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