1. Taw qhia
Hydroxypropyl Methylcellulose (HPMC) yog cov dej-soluble polymer dav siv hauv cov txheej txheem, cov khoom siv hauv tsev, tshuaj thiab lwm yam haujlwm. Hauv kev lag luam txheej, HPMC tsis yog tsuas yog siv los ua cov thickener, stabilizer thiab zaj duab xis qub, tab sis kuj yog ib qho zoo heev dispersant. Nws lub luag haujlwm tseem ceeb hauv cov txheej txheej suav nrog kev txhim kho kev ruaj ntseg ntawm cov txheej txheem, txhim kho rheology, txhim kho kev tsim kho kev ua haujlwm thiab qhov zoo ntawm cov txheej txheej kawg.
2. Cov yam ntxwv ntawm HPMC
Cov qauv molecular ntawm HPMC muaj cov pob txha cellulose thiab hydroxypropyl thiab methyl substituents. Nws cov qauv tshwj xeeb muab HPMC solubility hauv dej thiab muaj peev xwm tsim cov viscoelastic hauv cov kua dej. HPMC cuam tshuam nrog cov kuab tshuaj molecules los ntawm hydrogen bonding thiab van der Waals rog, yog li dissolves nyob rau hauv dej thiab tsim ib tug ruaj khov dispersion system.
Qhov hnyav molecular thiab degree ntawm kev hloov pauv (DS) ntawm HPMC cuam tshuam rau nws cov solubility thiab viscosity. Feem ntau hais lus, qhov hnyav dua molecular thiab qib ntawm kev hloov pauv nce lub sijhawm viscosity thiab kev sib cais ntawm HPMC. Cov yam ntxwv no yog qhov tseem ceeb rau kev ua haujlwm ntawm HPMC raws li txheej txheej dispersant.
3. Lub luag haujlwm ntawm HPMC hauv cov txheej txheem
3.1 Txhim kho pigment dispersibility
HPMC feem ntau yog siv los txhim kho dispersibility ntawm pigments nyob rau hauv coatings. Nyob rau hauv cov txheej txheem ntawm cov txheej txheem ntau lawm, agglomeration ntawm cov xim pigment yog ib qho teeb meem tshwm sim, uas ua rau cov txheej txheem tsis sib xws thiab tsis ruaj khov, cuam tshuam rau gloss thiab xim uniformity ntawm txheej. HPMC dispersants ua lub luag haujlwm hauv cov hauv qab no:
Electrostatic repulsion: Cov tshuaj tsim los ntawm HPMC dissolving nyob rau hauv dej muaj ib tug siab deg kev ua si thiab yuav adsorbed rau saum npoo ntawm pigment hais kom lawv them. Qhov no electrostatic repulsion cais cov xim pigment ntawm ib leeg thiab txo agglomeration.
Steric hindrance effect: Cov saw hlau polymer ntawm HPMC tuaj yeem tsim cov txheej txheem tiv thaiv ntawm cov xim xim, ua rau kom qhov sib nrug deb ntawm cov khoom, thiab yog li inhibit kev sib nrig sib attraction thiab agglomeration ntawm hais.
Cov nyhuv stabilization: HPMC ua ke nrog cov dej molecules los ntawm hydrogen bonds los tsim ib qho kev daws teeb meem ruaj khov, tiv thaiv cov xim xim los ntawm kev nyob hauv lub cev, thiab txhim kho kev ruaj ntseg ntawm txheej.
3.2 Txhim kho rheology
Lwm qhov tseem ceeb ntawm HPMC yog txhawm rau txhim kho rheology ntawm cov txheej txheej, uas yog, qhov ntws thiab deformation yam ntxwv ntawm txheej txheej. Cov khoom zoo rheological ntawm txheej txheej pab kom nws muaj kev sib kis tau zoo thiab qib theem thaum lub sij hawm tsim kho, tsim cov txheej txheem txheej txheej. HPMC cuam tshuam cov khoom rheological ntawm txheej txheej los ntawm cov txheej txheem hauv qab no:
Kev txhim kho Viscoelasticity: Lub polymer saw network qauv tsim los ntawm HPMC hauv dej muab cov tshuaj ib yam viscoelasticity. Qhov viscoelasticity no tuaj yeem kho tus cwj pwm ntws ntawm cov txheej, kom nws muaj qhov tsim nyog viscosity thaum txhuam, txo qis sagging thiab poob.
Shear thinning: HPMC cov kev daws teeb meem feem ntau pom cov khoom shear thinning, uas yog, lawv muaj viscosity siab dua ntawm cov nqi qis thiab qis dua ntawm cov nqi siab. Cov cuab yeej no ua rau cov txheej txheej muaj kev ruaj ntseg zoo dua hauv lub xeev zoo li qub thiab yooj yim rau kev sib kis thaum siv.
Thixotropy: Qee qhov HPMC cov kev daws teeb meem kuj nthuav tawm thixotropy, uas yog, cov viscosity rov qab los ntawm so, uas yog qhov tseem ceeb tshwj xeeb rau kev txo cov sagging thiab poob ntawm txheej.
3.3 Txhim kho txheej txheej
HPMC tsis tsuas yog muaj kev cuam tshuam tseem ceeb ntawm kev ua haujlwm ntawm cov txheej txheem thaum lub sij hawm tsim kho, tab sis kuj tseem txhim kho qhov zoo ntawm txheej txheej kawg. HPMC txhim kho kev ua haujlwm ntawm cov txheej txheem hauv qab no:
Txheej flatness: HPMC txhim kho lub rheology ntawm txheej, txhim khu kev sib kis thiab theem ntawm txheej, thiab ua rau cov txheej smoother thiab zoo ib yam.
Cov dej tiv thaiv thiab cov huab cua Kuj: HPMC cov qauv siv ua kom tsis taus thiab tiv thaiv cov txheej, thiab txhim kho huab cua tsis zoo ntawm cov txheej.
Adhesion: HPMC txhim kho qhov adhesion ntawm txheej, kom cov txheej tuaj yeem ruaj khov rau saum npoo ntawm lub substrate, thiab txhim kho cov kav ntev ntawm cov txheej.
4. Daim ntawv thov piv txwv ntawm HPMC
4.1 Architectural txheej
Hauv architectural coatings, HPMC yog siv los txhim kho cov dispersion ntawm pigments thiab rheology ntawm coatings, tshwj xeeb tshaj yog rau cov dej-raws li txheej. HPMC txhim kho kev ruaj ntseg thiab kev tsim kho ntawm cov txheej txheem, kom cov txheej txheej tau zoo dua qib thiab adhesion ntawm phab ntsa, thiab tiv thaiv cov yeeb yaj kiab los ntawm sagging thiab txheej tsis sib xws.
4.2 Muaj txheej txheej
HPMC kuj tau siv dav hauv kev lag luam txheej. Nws tsis yog tsuas yog txhim kho cov dispersibility ntawm cov xim, tab sis kuj txhim kho kev tsim kho ntawm cov txheej txheem, ua rau cov txheej txheem ntau dua rau cov hlau, yas thiab lwm yam substrates, thiab cov txheej txheej txheej txheej ua tau zoo dua qub.
4.3 Lwm cov txheej txheem
HPMC kuj tseem siv rau ntau yam txheej txheej tshwj xeeb, xws li hluav taws kub retardant coatings, anti-corrosion coatings, thiab lwm yam. Nws lub luag hauj lwm nyob rau hauv cov coatings yog tsuas yog los txhim kho cov stability ntawm cov coatings thiab cov txheej txheej zaj duab xis kev ua tau zoo, thiaj li hais tias cov coatings muaj kev ua tau zoo nyob rau hauv lub coatings. ntau yam complex ib puag ncig.
Raws li cov txheej txheej dispersant, HPMC plays lub luag haujlwm tseem ceeb hauv kev txhim kho cov dispersibility ntawm cov xim, txhim kho rheology ntawm txheej txheej thiab txhim kho kev ua haujlwm ntawm cov yeeb yaj kiab txheej. Nws cov qauv tshwj xeeb thiab kev ua haujlwm muab nws ntau yam ntawm daim ntawv thov kev cia siab hauv kev lag luam txheej. Nrog rau kev txhim kho cov txheej txheem txheej txheem, daim ntawv thov ntawm HPMC yuav nthuav dav ntxiv, muab ntau txoj hauv kev rau kev txhim kho thiab kev tsim kho tshiab ntawm txheej txheej.
Post lub sij hawm: Jun-25-2024