Hydroxypropyl methylcellulose (HPMC), ib qho tshuaj ntxiv uas siv ntau hauv cov txheej txheem txheej dej, ua ke ua kom tuab, khaws dej, ruaj khov, thiab ua haujlwm tau zoo dua, ua rau nws yog cov khoom siv tseem ceeb rau kev txhim kho kev ua haujlwm tag nrho ntawm cov txheej. Kev xaiv kom raug thiab kev siv HPMC kom raug tsis tsuas yog txhim kho kev ruaj khov ntawm cov txheej xwb tab sis kuj ua kom zoo dua qhov zoo ntawm zaj duab xis thiab kev xav ntawm txhuam.
1. Xaiv qhov Viscosity thiab Hloov Chaw Raws Li Lub Txheej Txheem
Qib viscosity ntawm HPMC muaj qhov cuam tshuam loj rau kev siv txheej. Cov qib viscosity siab (piv txwv li, siab dua 100,000 mPa · s) tuaj yeem txhim kho qhov viscosity qis mus rau nruab nrab ntawm lub kaw lus, pab txhim kho cov khoom tiv thaiv kev sagging thiab thixotropic thaum lub sijhawm thov; txawm li cas los xij, viscosity siab dhau ua rau muaj kev nyuaj ntawm kev sib tov thiab cuam tshuam rau qib. Qib viscosity nruab nrab (30,000–60,000 mPa · s) yog qhov tsim nyog dua rau feem ntau cov xim latex, ua tiav qhov sib npaug ntawm thickening thiab leveling. Rau cov txheej txheem phab ntsa sab nraud lossis cov txheej txheem siab-filler, viscosity siab dua yog pom zoo; thaum rau cov txheej txheem phab ntsa matte sab hauv, viscosity nruab nrab tuaj yeem siv los txhim kho kev du ntawm daim ntawv thov.
Qhov kev hloov pauv ntawm HPMC nrog methoxy thiab hydroxypropoxy pawg cuam tshuam rau nws qhov solubility thiab kev ruaj khov. Qib siab dua ntawm kev hloov pauv txhim kho kev solubility hauv dej thiab kev kam rau ntsev, ua rau muaj kev ruaj khov ntau dua hauv cov qauv uas muaj cov xim thiab cov khoom sau ntau lossis cov uas muaj kev hloov pauv pH tseem ceeb.
2. Paub Txog Txoj Kev Yaj Thiab Kev Faib Tawm Kom Yog
HPMC xav tau kev sib xyaw kom zoo kom ua tiav cov khoom tuab ruaj khov. Ob txoj kev sib xyaw ua ke yog:
Txoj Kev Sib Xyaws Kub Hauv Chav: Muab HPMC nchuav rau hauv dej txias kom sib npaug zos thaum sib xyaws ceev ceev, xyuas kom nws ntub tag yam tsis sib sau ua ke, tom qab ntawd txuas ntxiv sib xyaws kom txog thaum yaj tag. Tsis txhob ntxiv ntau ntau ib zaug, vim qhov no yuav ua rau muaj cov pawg uas nyuaj rau sib kis.
Txoj Kev Siv Dej Kub: Ua ntej, muab HPMC yaj rau hauv dej kub ntawm 80–90°C, tom qab ntawd ntxiv dej txias kom txias thiab yaj. Txoj kev no haum rau cov tshuaj uas muaj viscosity siab thiab txhim kho kev ua haujlwm ntawm kev yaj. Txhawm rau txhim kho kev ua haujlwm, HPMC uas daws qeeb tuaj yeem xaiv tau, txo cov teeb meem sib sau ua ke thiab txhim kho kev ua haujlwm ntawm kev tsim khoom.
3. Cov txheej txheem los txhim kho kev ruaj khov ntawm cov txheej txheem
HPMC tuaj yeem txhim kho qhov kev ncua ntawm cov xim thiab cov khoom sau thiab txo cov av noo thiab stratification, tab sis nws xav tau kev sib koom tes nrog lwm cov khoom ntxiv hauv cov qauv:
Hauv cov txheej PVC siab, qhov ntau ntawm HPMC ntxiv tuaj yeem nce ntxiv kom zoo dua qub kom ruaj khov cia khoom.
Tsis zoo li cov cellulose ether thickening systems, HPMC rhiab heev rau cov ntsev thiab calcium ions; yog li ntawd, yuav tsum xaiv cov ntsev-stabilized HPMC hauv cov systems uas muaj dej hardness siab lossis cov ntsiab lus CaCO₃ siab.
Yog tias cov txheej txheem ua rau tuab dhau, pH tuaj yeem nce ntxiv kom haum lossis siv cov khoom hloov kho rheology los txhim kho kev rov qab los ntawm shear.
4. Kev Txhim Kho Cov Txhuam Siv Thiab Zaj Duab Xis Zoo
HPMC muaj cov yam ntxwv zoo thixotropic thiab ntub dej, uas tuaj yeem txhim kho qhov kev xav ntawm txhuam thiab ua kom muaj kev npog txheej. Cov txheej txheem siv suav nrog:
Hauv cov txheej txheem siv zaus siab (xws li kev tsim cov txheej txheem), qhov viscosity tuaj yeem txo qis me ntsis kom txhim kho qhov du ntawm cov txheej txheem roller.
Txhawm rau txhim kho qib, HPMC tuaj yeem sib xyaw nrog HEUR lossis ASE-hom thickeners los tsim kom muaj qhov profile rheological zoo dua.
Thaum siv xim rau hauv qhov chaw qhuav, kev nce cov ntsiab lus HPMC pab txhim kho kev khaws dej thiab tiv thaiv cov npoo qhuav, cov cim txhuam, lossis cov qhov tsis zoo ntawm zaj duab xis.
5. Tswj Xyuas Tus Nqi Ntxiv Kom Zoo
Feem ntau, qhov ntxiv HPMC rau cov xim pleev xim latex rau phab ntsa sab hauv yog kwv yees li 0.2–0.5%, thaum rau phab ntsa sab nraud nws tuaj yeem nce mus txog 0.3–0.6%. Txawm li cas los xij, kev hloov kho yuav tsum tau ua raws li hom PVC, cov xim, cov khoom sau, thiab cov txheej txheem tuab. Kev ntxiv ntau dhau yuav ua rau tsis zoo, lub sijhawm qhuav ntev, thiab txawm tias muaj kev xav nplaum.
6. Siv Synergistic nrog Lwm Cov Thickeners
Qhov zoo tshaj plaws ntawm cov xim rheology feem ntau yog nyob ntawm kev sib xyaw ua ke ntawm cov thickeners.HPMCtswj tau qhov nruab nrab mus rau qis shear thickening thiab dej khaws cia; HEUR tswj tau qhov siab shear viscosity; thiab ASE muab qhov zoo dua tus nqi. Kev sib xyaw ua ke ntawm peb yam no tsim kom muaj qhov rheological profile zoo tagnrho, ua rau cov xim uas tsis sagging thiab yooj yim rau kev siv.
Lub sijhawm tshaj tawm: Lub Kaum Ob Hlis-03-2025