Qhov tshwm sim ntawm viscosity poob thaum lub sijhawm khaws cov xim yog ib qho teeb meem tshwm sim, tshwj xeeb tshaj yog tom qab khaws cia ntev, viscosity ntawm cov xim txo qis, cuam tshuam rau kev tsim kho thiab cov khoom zoo. Qhov txo qis hauv viscosity yog cuam tshuam nrog ntau yam, xws li kub, av noo, hnyav volatilization, polymer degradation, thiab lwm yam, tab sis kev cuam tshuam nrog cov thickener cellulose ether yog qhov tseem ceeb tshwj xeeb.
1. Lub luag haujlwm tseem ceeb ntawm cellulose ether
Cellulose ether yog cov thickener uas siv dav hauv cov xim dej. Lawv lub luag haujlwm tseem ceeb suav nrog:
Thickening nyhuv: Cellulose ether tuaj yeem tsim cov qauv kev sib txuas ntawm peb sab los ntawm kev nqus dej, yog li ua kom cov viscosity ntawm lub cev thiab txhim kho thixotropy thiab kev tsim kho ntawm cov xim.
Suspension stabilization nyhuv: Cellulose ether tuaj yeem tiv thaiv cov sedimentation ntawm cov khoom xws li pigments thiab fillers nyob rau hauv cov xim thiab tuav lub uniformity ntawm cov xim.
Cov cuab yeej ua yeeb yaj kiab: Cellulose ether tuaj yeem cuam tshuam rau cov yeeb yaj kiab tsim cov khoom ntawm cov xim, ua rau cov txheej txheem muaj qee qhov toughness thiab durability.
Muaj ntau hom cellulose ethers, suav nrog methyl cellulose (MC), hydroxyethyl cellulose (HEC), hydroxypropyl methyl cellulose (HPMC), thiab lwm yam. Cov ntaub ntawv no muaj qhov sib txawv solubility, thickening muaj peev xwm thiab khaws cia nyob rau hauv coatings.
2. Lub ntsiab yog vim li cas rau viscosity txo
Thaum lub sij hawm cia ntawm coatings, qhov viscosity txo yog feem ntau tshwm sim los ntawm cov hauv qab no yog vim li cas:
(1) Degradation ntawm cellulose ethers
Cov nyhuv thickening ntawm cellulose ethers hauv coatings nyob ntawm qhov loj ntawm lawv qhov hnyav molecular thiab kev ncaj ncees ntawm lawv cov qauv molecular. Thaum lub sij hawm cia, yam xws li kub, acidity thiab alkalinity, thiab microorganisms yuav ua rau degradation ntawm cellulose ethers. Piv txwv li, thaum lub sij hawm ntev cia, lub acidic los yog alkaline Cheebtsam nyob rau hauv lub txheej yuav hydrolyze lub molecular saw ntawm cellulose ether, txo nws molecular hnyav, thiab yog li tsis muaj zog nws thickening nyhuv, ua rau ib tug txo nyob rau hauv viscosity.
(2) Solvent volatilization thiab ya raws tsiv teb tsaws
Solvent volatilization lossis ya raws tsiv teb tsaws hauv cov txheej yuav cuam tshuam rau lub xeev solubility ntawm cellulose ether. Thaum lub sij hawm cia, ib feem ntawm cov dej yuav evaporate los yog tsiv mus nyob rau saum npoo ntawm txheej, ua rau cov khoom faib ntawm cov dej nyob rau hauv lub txheej tsis sib xws, yog li cuam tshuam rau qhov o ntawm cellulose ether thiab ua rau txo qis hauv viscosity hauv cheeb tsam.
(3) Microbial nres
Kev loj hlob ntawm microbial yuav tshwm sim nyob rau hauv txheej thaum nws tsis raug muab khaws cia los yog cov khoom khaws cia tsis zoo. Cov kab mob tuaj yeem decompose cellulose ethers thiab lwm cov organic thickeners, ua rau lawv cov thickening tsis muaj zog thiab ua rau cov viscosity ntawm cov txheej yuav txo. Dej-raws li txheej, tshwj xeeb, yog qhov chaw zoo rau kev loj hlob microbial vim tias lawv muaj cov dej ntau.
(4) Kub kub aging
Nyob rau hauv qhov kub thiab txias cia, lub cev lossis tshuaj qauv ntawm cellulose ether molecular saw yuav hloov. Piv txwv li, cellulose ethers yog nquag oxidation los yog pyrolysis ntawm qhov kub thiab txias, ua rau tsis muaj zog ntawm thickening nyhuv. Cov kub kub kuj tseem ua kom hnyav volatilization thiab dej evaporation, ntxiv cuam tshuam rau viscosity stability.
3. Cov txheej txheem los txhim kho kev ruaj ntseg ntawm cov txheej txheej
Txhawm rau txo qhov txo qis hauv viscosity thaum khaws cia thiab txuas ntxiv lub neej ntawm cov txheej, cov kev ntsuas hauv qab no tuaj yeem ua:
(1) Xaiv txoj cai cellulose ether
Ntau hom cellulose ethers muaj kev ua tau zoo sib txawv raws li kev ruaj ntseg cia. Cellulose ethers uas muaj qhov hnyav molecular feem ntau muaj cov nyhuv thickening zoo dua, tab sis lawv qhov ruaj khov ruaj khov tsis zoo, thaum cellulose ethers nrog qhov hnyav molecular yuav muaj kev cia zoo dua. Yog li ntawd, thaum tsim cov mis, cellulose ethers nrog zoo cia ruaj khov yuav tsum tau xaiv, los yog cellulose ethers yuav tsum tau compounded nrog rau lwm cov thickeners los txhim kho lawv cov cia tsis kam.
(2) Tswj pH ntawm txheej
Lub acidity thiab alkalinity ntawm txheej txheej muaj ib qho tseem ceeb ntawm kev ruaj ntseg ntawm cellulose ethers. Hauv kev tsim qauv, pH tus nqi ntawm cov txheej yuav tsum tau tswj kom tsis txhob muaj acidic lossis alkaline ib puag ncig kom txo tau qhov degradation ntawm cellulose ethers. Nyob rau tib lub sijhawm, ntxiv qhov tsim nyog ntawm pH adjuster lossis tsis tuaj yeem pab tswj cov pH ntawm lub cev.
(3) Ua kom muaj kev siv tshuaj tiv thaiv
Txhawm rau tiv thaiv microbial yaig, qhov tsim nyog ntawm cov tshuaj tua kab mob yuav tsum tau ntxiv rau txheej txheej. Cov tshuaj tua kab mob tuaj yeem cuam tshuam kev loj hlob ntawm cov kab mob, yog li tiv thaiv cov organic xws li cellulose ether los ntawm kev decomposed thiab tswj kev ruaj ntseg ntawm txheej. Cov tshuaj tiv thaiv tsim nyog yuav tsum raug xaiv raws li txheej txheej txheej txheej thiab khaws cia ib puag ncig, thiab lawv cov txiaj ntsig yuav tsum tau kuaj xyuas tsis tu ncua.
(4) Tswj qhov chaw cia khoom
Qhov ntsuas kub thiab av noo ntawm cov txheej txheej muaj qhov cuam tshuam ncaj qha rau viscosity stability. Cov txheej yuav tsum tau muab cia rau hauv qhov chaw qhuav thiab txias, tsis txhob muaj qhov kub thiab txias thiab cov av noo siab kom txo tau cov kuab tshuaj volatilization thiab cellulose ether degradation. Tsis tas li ntawd, lub ntim ntim tau zoo tuaj yeem txo qhov kev tsiv teb tsaws thiab evaporation ntawm dej thiab ncua qhov txo qis hauv viscosity.
4. Lwm yam cuam tshuam rau viscosity
Ntxiv nrog rau cellulose ethers, lwm yam khoom siv hauv txheej txheej kuj tseem tuaj yeem cuam tshuam qhov kev hloov pauv hauv viscosity. Piv txwv li, hom thiab concentration ntawm pigments, volatilization tus nqi ntawm cov kuab tshuaj, thiab cov compatibility ntawm lwm thickeners los yog dispersants yuav cuam tshuam rau viscosity stability ntawm txheej. Yog li ntawd, tag nrho cov qauv tsim ntawm txheej txheej thiab kev sib cuam tshuam ntawm cov khoom siv kuj tseem yog cov ntsiab lus tseem ceeb uas yuav tsum tau them sai sai rau.
Qhov txo qis hauv viscosity thaum lub sij hawm cia ntawm cov txheej yog ze ze rau cov yam xws li degradation ntawm cellulose ethers, hnyav volatilization, thiab dej tsiv teb tsaws. Txhawm rau txhim kho kev ruaj ntseg ntawm cov txheej txheej, cov khoom tsim nyog ntawm cov cellulose ether yuav tsum tau xaiv, pH ntawm txheej yuav tsum tau tswj, kev ntsuas tiv thaiv corrosion yuav tsum muaj zog, thiab qhov chaw cia khoom yuav tsum tau ua kom zoo dua. Los ntawm cov qauv tsim qauv tsim nyog thiab kev tswj xyuas zoo, qhov teeb meem ntawm viscosity txo thaum lub sij hawm cia ntawm cov txheej txheem tuaj yeem txo qis, thiab cov khoom lag luam kev ua tau zoo thiab kev sib tw ua lag luam tuaj yeem txhim kho.
Post lub sij hawm: Sep-27-2024