Kev Txhim Kho Keeb Kwm ntawm Redispersible Powder

Redispersible hmoov (RDP) yog ib hom polymer hmoov siv nyob rau hauv kev tsim kho kev lag luam raws li ib tug additive nyob rau hauv cement-based khoom xws li mortar, grouts, thiab self-leveling compounds. RDPs tau tsim thawj zaug hauv xyoo 1950 thiab txij li ntawd los ua ib qho tseem ceeb hauv cov khoom siv niaj hnub no. Hauv tsab xov xwm no, peb yuav ua tib zoo saib cov keeb kwm kev loj hlob ntawm RDP thiab nws qhov tseem ceeb hauv kev tsim kho kev lag luam.

Cov xyoo thaum ntxov

Thawj RDPs tau tsim nyob rau xyoo 1950 los ntawm lub tuam txhab German hu ua Wacker Chemie AG. Thaum lub sijhawm, Wacker Chemie AG tab tom tsim cov khoom siv hluavtaws tshiab kom tau raws li qhov xav tau ntawm kev tsim kho tom qab ua tsov rog. Lawv tab tom nrhiav ib txoj hauv kev los txhim kho cov khoom ntawm cov khoom siv cement, xws li dej tsis kam, kav ntev, thiab yoog raws.

Thaum ntxov, RDPs tau tsim los ntawm dissolving polyvinyl acetate (PVA) nyob rau hauv ib qho hnyav thiab tom qab ntawd txau cov tshuaj rau hauv chav sov uas cov kuab tshuaj yuav evaporate, tawm hauv cov hmoov zoo. Cov hmoov no tuaj yeem yooj yim dispersed hauv dej thiab siv los ua ib qho ntxiv hauv cov khoom siv cement.

Txawm li cas los xij, muaj qee qhov kev txwv rau daim ntawv no thaum ntxov ntawm RDP. Piv txwv li, nws yog ib qho nyuaj rau kev tswj cov particle loj thiab cov duab ntawm cov hmoov, uas yuav cuam tshuam nws cov kev ua tau zoo ntawm cov khoom siv cement. Tsis tas li ntawd, cov hmoov tsis ruaj khov heev thiab feem ntau yuav tsim cov pob los yog clumps, ua rau nws nyuaj rau kev siv thiab siv.

Kev txhim kho thiab kev tsim kho tshiab

Tau ntau xyoo, cov kws tshawb fawb thiab cov kws tsim qauv tau txhim kho cov txheej txheem tsim khoom thiab cov khoom ntawm RDPs. Piv txwv li, kev nce qib hauv polymer chemistry tau ua rau kev txhim kho cov polymers tshiab uas muaj kev txhim kho kev ua tau zoo thiab ruaj khov.

Ib qho kev nce qib tseem ceeb tshaj plaws hauv RDP thev naus laus zis tuaj rau xyoo 1980s nrog kev qhia txog cov txheej txheem tsim khoom tshiab hu ua tsuag ziab. Cov txheej txheem no suav nrog kev txau cov polymer emulsion rau hauv chav sov uas cov dej evaporated, tawm hauv qab cov hmoov zoo. Txoj kev no tso cai rau kev tswj hwm ntau dua ntawm qhov loj me thiab cov duab ntawm cov hmoov, uas ua rau muaj kev ua tau zoo thiab kev kwv yees ntau dua hauv cov khoom siv cement.

Lwm qhov kev tsim kho tshiab hauv RDP thev naus laus zis tuaj nrog kev taw qhia ntawm cov roj hmab latex (RPL), uas yog tsim los ntawm latex emulsion es tsis txhob PVA. RPLs muab kev txhim kho cov dej tsis kam thiab adhesion piv rau PVA-raws li RDPs, ua rau lawv muaj kev xaiv nrov rau cov ntawv siv sab nrauv xws li stucco thiab EIFS (cov rwb thaiv tsev sab nrauv thiab cov txheej txheem tiav).

Cov ntawv thov thiab cov txiaj ntsig

RDPs muaj ntau yam txiaj ntsig hauv kev tsim kho kev lag luam, suav nrog kev txhim kho kev ua haujlwm, adhesion, thiab dej tsis kam. Lawv tuaj yeem siv tau ntau yam ntawm cov khoom siv cement, xws li mortars, grouts, self-leveling compounds, thiab pobzeb adhesives.

Ib qho txiaj ntsig tseem ceeb ntawm RDPs yog lawv lub peev xwm los txhim kho kev ua haujlwm thiab yooj yim ntawm kev siv cov khoom siv cement. Lawv tuaj yeem txo cov dej xav tau kom ua tiav qhov xav tau sib xws, uas tuaj yeem txhim kho lub zog thiab ua haujlwm ntev ntawm cov khoom tiav. Lawv kuj tuaj yeem pab txo qhov tawg thiab shrinkage, uas tuaj yeem tshwm sim thaum cov khoom siv cement qhuav sai heev.

Tsis tas li ntawd, RDPs tuaj yeem txhim kho qhov adhesion ntawm cov khoom cement-based rau ntau yam substrates, suav nrog ntoo, hlau, thiab masonry. Lawv kuj tuaj yeem txhim kho cov dej tsis kam thiab ua haujlwm ntev ntawm cov khoom siv cement, ua rau lawv zoo tagnrho rau kev siv hauv qhov chaw ntub dej lossis thaj chaw uas muaj kev tsheb loj lossis cuam tshuam.

Xaus

Hauv kev xaus, keeb kwm kev loj hlob ntawm RDP tau raug cim los ntawm kev nce qib tseem ceeb hauv cov tshuaj polymer thiab cov txheej txheem tsim khoom. Los ntawm nws qhov pib txo qis hauv xyoo 1950, RDP tau dhau los ua qhov tseem ceeb hauv cov khoom siv niaj hnub no, muab ntau yam txiaj ntsig ntawm kev ua haujlwm, adhesion.