HPMC ua li cas txhim kho qhov adhesion ntawm latex xim?

Hydroxypropyl Methylcellulose (HPMC, Hydroxypropyl Methylcellulose) yog semi-synthetic, inert, non-toxic cellulose derivative uas yog dav siv nyob rau hauv architectural coatings, tshwj xeeb tshaj yog cov xim latex. Qhov sib ntxiv ntawm HPMC tsis tsuas yog txhim kho kev ruaj ntseg, rheology thiab txhuam ntawm cov xim latex, tab sis kuj tseem txhim kho nws cov adhesion.

Cov yam ntxwv tseem ceeb ntawm HPMC

HPMC yog ib qho uas tsis yog-ionic cellulose ether nrog cov dej solubility zoo, kev ua yeeb yaj kiab thiab cov khoom nplaum. Nws cov qauv molecular muaj cov pab pawg ua haujlwm xws li hydroxyl, methoxy thiab hydroxypropyl, uas muab HPMC tshwj xeeb lub cev thiab tshuaj lom neeg, xws li:

Cov dej zoo solubility: HPMC sai sai yaj hauv dej txias los tsim cov kua nplaum, uas yooj yim rau disperse latex xim sib npaug.
Cov khoom thickening zoo heev: Nws tuaj yeem ua kom cov viscosity ntawm cov xim latex thiab txhim kho nws cov adhesion ntawm ntsug qhov chaw.
Zaj duab xis-tsim cov khoom: HPMC tuaj yeem tsim cov yeeb yaj kiab tsis sib xws thaum lub sijhawm ziab ntawm cov xim pleev xim, txhim kho cov neeg kho tshuab lub zog ntawm cov xim pleev xim.
Kev ruaj ntseg: HPMC cov tshuaj muaj kev ruaj ntseg zoo thiab tsis yooj yim cuam tshuam los ntawm kub thiab pH tus nqi, uas yuav pab txhim kho kev ruaj ntseg cia ntawm cov xim latex.

Qhov sib xyaw ntawm cov xim latex thiab yam cuam tshuam rau adhesion

Cov xim latex feem ntau yog tsim los ntawm cov yeeb yaj kiab ua yeeb yaj kiab (xws li emulsion polymers), pigments, fillers, additives (xws li thickeners, dispersants, defoaming agents) thiab dej. Nws adhesion yog cuam tshuam los ntawm ntau yam:

Substrate zog: Qhov roughness, tshuaj muaj pes tsawg leeg thiab lub zog ntawm lub substrate nto yuav tag nrho cov cuam tshuam rau adhesion ntawm latex xim.
Txheej txheej: xaiv cov yeeb yaj kiab tsim cov tshuaj, qhov sib piv ntawm cov khoom ntxiv, tus nqi evaporation ntawm cov kuab tshuaj, thiab lwm yam. ncaj qha cuam tshuam rau adhesion peev xwm ntawm cov xim zaj duab xis.
Kev tsim kho tshuab: Kev tsim kho qhov kub thiab txias, av noo, txheej txheem txheej, thiab lwm yam kuj tseem ceeb heev uas cuam tshuam rau adhesion.

HPMC feem ntau txhim kho adhesion hauv latex xim los ntawm cov hauv qab no:

1. Txhim kho txheej txheej zaj duab xis
HPMC ua kom cov viscosity ntawm cov xim latex, tso cai rau nws tsim ib qho yeeb yaj kiab, du thaum siv. Cov txheej txheem txheej txheej zaj duab xis no txo ​​qhov tsim ntawm npuas thiab txo cov teeb meem adhesion los ntawm txheej txheej zaj duab xis tsis xws luag.

2. Muab ntxiv adhesion
Cov hydroxyl thiab ether bonds hauv HPMC tuaj yeem ua rau lub cev adsorb lossis tshuaj lom neeg nrog rau lub substrate nto, muab ntxiv adhesion. Piv txwv li, hydrogen-bonding kev sib cuam tshuam ntawm HPMC thiab hydroxyl los yog lwm pawg polar ntawm substrate pab txhim kho zaj duab xis adhesion.

3. Txhim khu cov dispersion ntawm pigments thiab fillers
HPMC tuaj yeem cuam tshuam cov pigments thiab fillers nyob rau hauv cov xim latex thiab tiv thaiv lawv los ntawm agglomerating, kom cov pigments thiab fillers yog sib npaug zos rau hauv cov xim zaj duab xis. Qhov kev faib tawm niaj hnub no tsis tsuas yog txhim kho qhov smoothness ntawm cov xim zaj duab xis, tab sis kuj txhim kho cov neeg kho tshuab lub zog ntawm cov xim zaj duab xis, ntxiv dag zog rau adhesion.

4. Kho qhov ziab nrawm ntawm cov xim pleev xim
HPMC muaj kev tswj cov nyhuv ntawm qhov ziab nrawm ntawm cov xim zaj duab xis. Kev ziab kom qhuav me ntsis pab kom tsis txhob muaj qhov adhesion los ntawm kev ntxhov siab ntau dhau ntawm cov yeeb yaj kiab txheej. HPMC ua rau cov xim zaj duab xis kom qhuav ntau sib npaug los ntawm kev ua kom cov dej ntws tawm qeeb qeeb, yog li txo qhov kev ntxhov siab hauv cov xim pleev xim thiab ua kom cov adhesion.

5. Muab cov dej noo tiv thaiv thiab tawg tsis kam
Cov yeeb yaj kiab txuas ntxiv tsim los ntawm HPMC hauv cov xim pleev xim muaj cov nyhuv noo noo thiab txo qhov yaig ntawm cov substrate los ntawm noo noo. Tsis tas li ntawd, lub toughness thiab elasticity ntawm HPMC zaj duab xis pab nqus cov shrinkage kev nyuaj siab ntawm cov xim zaj duab xis thaum lub sij hawm ziab thiab txo qhov tawg ntawm cov xim zaj duab xis, yog li tuav zoo adhesion.

Cov ntaub ntawv sim thiab cov qauv siv
Txhawm rau txhawm rau txheeb xyuas qhov cuam tshuam ntawm HPMC ntawm cov xim pleev xim latex, cov ntaub ntawv sim tuaj yeem txheeb xyuas. Cov hauv qab no yog ib qho kev sim tsim qauv thiab cov txiaj ntsig pom:

kev sim tsim
Kev Npaj Qauv: Npaj cov qauv xim latex uas muaj qhov sib txawv ntawm HPMC.
Kev xaiv substrate: Xaiv cov phaj hlau du thiab ntxhib cement board raws li kev sim substrate.
Adhesion test: Siv txoj kev rub tawm los yog txoj kev hla-hatch rau kev kuaj adhesion.

Kev sim cov txiaj ntsig
Cov txiaj ntsig kev sim qhia tau hais tias thaum HPMC concentration nce, qhov adhesion ntawm latex xim ntawm cov substrates sib txawv nce. Txhim kho adhesion los ntawm 20-30% ntawm cov hlau du thiab 15-25% ntawm cov cement ntxhib.

Cov ntaub ntawv no qhia tau hais tias qhov sib ntxiv ntawm qhov tsim nyog ntawm HPMC tuaj yeem txhim kho qhov adhesion ntawm latex xim, tshwj xeeb tshaj yog ntawm cov substrates du.

Cov lus qhia siv
Txhawm rau kom siv tag nrho cov txiaj ntsig ntawm HPMC hauv kev txhim kho latex xim adhesion nyob rau hauv daim ntawv thov, cov ntsiab lus hauv qab no yuav tsum tau sau tseg:

Txhim kho tus nqi ntawm HPMC ntxiv: Tus nqi ntawm HPMC ntxiv yuav tsum tau hloov kho raws li cov qauv ntawm cov xim latex thiab cov yam ntxwv ntawm cov substrate. Cov concentration ntau dhau tuaj yeem ua rau cov txheej txheem tuab heev, cuam tshuam rau qhov kawg tshwm sim.
Kev koom tes nrog lwm cov tshuaj ntxiv: HPMC yuav tsum muaj kev sib koom tes nrog cov thickeners, dispersants thiab lwm yam additives kom ua tiav cov txheej txheem zoo tshaj plaws.
Kev tswj ntawm kev tsim kho: Thaum lub sij hawm txheej txheej txheej, qhov kub thiab av noo tsim nyog yuav tsum tau tswj xyuas kom muaj txiaj ntsig zoo ntawm HPMC.

Raws li ib qho tseem ceeb latex xim additive, HPMC ho txhim kho cov adhesion ntawm latex xim los ntawm kev txhim kho cov txheej txheej zaj duab xis, muab ntxiv adhesion, pab txhawb pigment dispersion, kho kom qhuav ceev, thiab muab noo noo tsis kam thiab tawg kuj. Hauv kev siv tiag tiag, qhov kev siv nyiaj ntawm HPMC yuav tsum raug kho kom haum raws li cov kev xav tau tshwj xeeb thiab siv nrog rau lwm cov tshuaj ntxiv kom ua tiav cov txheej txheem zoo tshaj plaws thiab kev ua kom zoo. Daim ntawv thov ntawm HPMC tsis tsuas yog txhim kho lub cev thiab tshuaj lom neeg ntawm cov xim latex, tab sis kuj nthuav dav nws daim ntawv thov ntau yam ntawm cov substrates, muab ntau txoj hauv kev rau kev lag luam vaj tsev coatings.