Hydroxypropyl methylcellulose (HPMC)yog ib qho cellulose ether uas tsis yog ionic nrog cov khoom zoo heev uas ua rau tuab, khaws dej, tsim zaj duab xis, thiab tawg, siv dav hauv cov ntaub ntawv tsim kho, tshuaj pleev xim, thiab tshuaj. Hauv cov ntaub ntawv tsim kho gypsum, kev qhia txog HPMC tuaj yeem txhim kho lawv txoj haujlwm tau zoo, txhim kho kev nthuav dav, khaws dej, thiab tiv thaiv kev poob qis, ua rau cov khoom siv yooj yim siv thiab ruaj khov dua ntawm qhov chaw.
1. Txoj Haujlwm ntawm HPMC hauv Gypsum Systems
Cov ntaub ntawv gypsum feem ntau yog ua los ntawm hemihydrate gypsum ua cov cementitious matrix. Tom qab ntxiv dej, nws hydrates los ua dihydrate gypsum crystals, tsim kom muaj cov qauv network ruaj khov. Vim yog qhov ceev ceev hardening thiab tsis khaws dej ntawm gypsum, teeb meem xws li shrinkage cracking, sagging, thiab tsis nplaum yooj yim tshwm sim thaum lub sijhawm tsim kho. Kev qhia txog HPMC tuaj yeem txhim kho kev ua haujlwm ntawm lub kaw lus los ntawm cov txheej txheem hauv qab no:
Kev Nqus Tawm Lub Cev thiab Kev Tswj Xyuas Cov Qauv Network: HPMC cov molecules sib cuam tshuam nrog cov dej molecules thiab qhov chaw ntawm gypsum crystals los ntawm hydrogen bonds, tsim cov viscoelastic polymer zaj duab xis uas qeeb qeeb dej poob thiab ntev lub sijhawm ua haujlwm ntawm gypsum slurry. Kev Tswj Xyuas Thickening thiab Rheological: HPMC yaj hauv dej los tsim cov tshuaj viscosity siab, uas txhim kho thixotropy ntawm slurry. Nws qhia txog viscosity siab thiab tiv thaiv kev sagging thaum so, thaum tswj hwm cov kua zoo hauv qab kev sib xyaw lossis kev tsim kho shear zog, pab txhawb kev siv.
Kev Tswj Xyuas Cov Txheej Txheem Hydration: HPMC muaj qee qhov cuam tshuam rau cov txheej txheem yaj-crystallization ntawm hemihydrate gypsum, tiv thaiv kev ntxhov siab sab hauv los ntawm kev ua kom sai hauv zos crystallization thiab txhim kho cov qauv sib xws.
2. Kev Cuam Tshuam ntawm HPMC rau Kev Ua Haujlwm ntawm Gypsum
2.1. Kev Khaws Dej Zoo Dua thiab Lub Sijhawm Ua Haujlwm Ntev Dua
Cov txheej txheem gypsum feem ntau poob dej thaum muaj qhov kub thiab txias lossis qhuav, ua rau cov hmoov av lossis tawg. HPMC tuaj yeem txhim kho qhov ceev ntawm lub kaw lus los ntawm nws cov khoom ua yeeb yaj kiab uas ua rau dej khaws cia, ua rau dej siv tau tag nrho hauv cov tshuaj tiv thaiv hydration. Cov kev tshawb fawb tau qhia tias thaum HPMC ntxiv yog 0.1% -0.3%, qhov ceev ntawm cov dej khaws cia ntawm cov gypsum slurry tuaj yeem nce ntxiv los ntawm 85% mus rau ntau dua 95%, thaum lub sijhawm ua haujlwm ntev dua li 30% -50%.
2.2. Kev Ua Haujlwm Zoo Dua thiab Cov Khoom Tiv Thaiv Kev Qaug Zog
HPMC ua rau lub kaw lus viscosity thiab thixotropy nce ntxiv, ua rau muaj kev du thiab tiaj tiaj ntawm qhov chaw thaum lub sijhawm thov, tiv thaiv cov teeb meem sagging ntawm cov chaw ntsug. Tshwj xeeb tshaj yog nyob rau hauv cov plasters txau thiab leveling, kev ntxiv HPMC kom zoo dua qub txhim kho kev tswj hwm kev ntws thiab txo qhov xav tau kev ua tiav theem ob.
2.3. Kev Txhim Kho Lub Zog Sib Koom Tes thiab Qhov Zoo Ntawm Qhov Chaw
Vim tias HPMC tsim cov zaj duab xis polymer txuas ntxiv mus rau saum npoo ntawm cov plaster tawv, nws ua rau muaj kev sib txuas ntawm cov plaster thiab lub hauv paus lossis cov ntaub ntawv tiav. Tib lub sijhawm, HPMC txhim kho qhov kev faib tawm ntawm cov qauv pore ntawm cov plaster tawv, ua rau muaj qhov chaw ntom dua thiab du dua, txhim kho qhov zoo li thiab kev ruaj khov ntawm cov khoom tiav.
2.4. Kev Tswj Xyuas Lub Sijhawm Teem Caij thiab Daim Ntawv Thov
Cov qib sib txawv ntawm kev hloov pauv thiab qib viscosity ntawm HPMC muaj cov teebmeem sib txawv rau lub sijhawm teeb tsa plaster. Feem ntau, HPMC uas muaj viscosity qis muaj cov teebmeem me dua rau kev ncua kev teeb tsa, thaum cov khoom uas muaj viscosity siab muaj cov teebmeem qeeb qeeb. Los ntawm kev tswj cov nyiaj ntxiv thiab hom khoom, lub sijhawm teeb tsa ntawm cov ntaub ntawv gypsum tuaj yeem hloov kho tau yooj yim kom ua tau raws li qhov xav tau ntawm kev tsim kho ntawm cov txheej txheem sib txawv.
3. Txoj Kev Txhim Kho Kev Ua Haujlwm ntawm HPMC-Hloov Kho Gypsum
3.1. Kev Xaiv Hom HPMC thiab Dosage Rational
Rau cov tshuab gypsum, nws raug pom zoo kom siv cov viscosity nruab nrab mus rau siab (40,000–80,000 mPa·s) kev tsim kho-qib HPMC kom sib npaug ntawm kev khaws dej thiab kev ua haujlwm tau zoo. Kev ntxiv ntau dhau yuav ua rau cov nplaum tuab dhau thiab kev tsim kho nyuaj; yog li ntawd, feem ntau nws raug nquahu kom tswj cov koob tshuaj ntawm 0.1% thiab 0.3%.
3.2. Kev Siv Tshuab Sib Xyaws
HPMC tuaj yeem sib xyaw nrog cov khoom ntxiv xws li hmoov txhuv nplej siab ether thiab redispersible polymer hmoov (RDP) kom ua tiav kev ua haujlwm zoo ntawm rheology thiab adhesion. Piv txwv li, hmoov txhuv nplej siab ether tuaj yeem txhim kho thixotropy, thiab RDP tuaj yeem txhim kho kev tiv thaiv kab nrib pleb thiab adhesion; kev sib xyaw ua ke ntawm peb yam tuaj yeem txhim kho qhov ua haujlwm tag nrho ntawm gypsum system.
3.3. Cov Qauv Tshwj Xeeb rau Cov Txheej Txheem Gypsum Sib Txawv
Hauv ntau daim ntawv thov xws li plastering gypsum, leveling gypsum, thiab gypsum putty, HPMC ua lub luag haujlwm sib txawv: plastering gypsum hais txog kev khaws dej thiab tiv thaiv kev sagging, leveling gypsum hais txog kev teeb tsa qeeb thiab cov khoom leveling, thaum putty xav tau qhov chaw du thiab cov khoom ua zaj duab xis. Kev xaiv lub hom phiaj ntawm HPMC molecular qhov hnyav thiab qib ntawm kev hloov pauv yog qhov tseem ceeb rau kev ua tiav kev ua haujlwm zoo tshaj plaws.
HPMCmuaj qhov cuam tshuam loj heev rau cov ntaub ntawv gypsum. Los ntawm ntau txoj hauv kev, suav nrog kev khaws dej, thickening, qeeb teeb tsa, thiab kev txhim kho tus cwj pwm rheological, nws txhim kho qhov ua haujlwm tau zoo thiab cov khoom tiav zoo ntawm gypsum systems. Kev xaiv zoo ntawm HPMC hom thiab koob tshuaj, ua ke nrog lwm cov khoom ntxiv rau kev tsim cov qauv zoo tshaj plaws, yog ib qho kev taw qhia tseem ceeb rau kev tsim cov ntaub ntawv tsim cov qauv gypsum yav tom ntej. Nrog rau kev txhawb nqa ntawm lub tsev ntsuab thiab kev tsim kho ua ntej, HPMC-hloov gypsum yuav qhia txog kev siv dav dua hauv kev ua haujlwm siab, cov ntaub ntawv tsim kho ruaj khov.
Lub sijhawm tshaj tawm: Kaum Ib Hlis-07-2025