1. Hom thickeners thiab thickening mechanism
(1) Inorganic thickener:
Inorganic thickeners nyob rau hauv dej-raws li systems yog feem ntau av nplaum.Xws li: bentonite.Kaolin thiab diatomaceous lub ntiaj teb (lub ntsiab tivthaiv yog SiO2, uas muaj ib tug ntxeem tau qauv) yog tej zaum kuj siv los ua auxiliary thickeners rau thickening systems vim lawv cov khoom raug ncua.Bentonite yog siv ntau dua vim nws cov dej-swellability siab.Bentonite (Bentonite), tseem hu ua bentonite, bentonite, thiab lwm yam, cov ntxhia tseem ceeb ntawm bentonite yog montmorillonite uas muaj me me ntawm alkali thiab alkaline ntiaj teb hlau hydrous aluminosilicate minerals, teej tug mus rau pawg aluminosilicate, nws cov tshuaj formula yog: (Na Ca)(Al,Mg)6(Si4O10)3(OH)6•nH2O.Kev nthuav dav ntawm bentonite yog qhia los ntawm kev nthuav dav, uas yog, qhov ntim ntawm bentonite tom qab o nyob rau hauv dilute hydrochloric acid tov yog hu ua expansion peev, qhia nyob rau hauv ml / gram.Tom qab cov bentonite thickener absorbs dej thiab swells, lub ntim tuaj yeem ncav cuag ob peb zaug lossis kaum zaus uas ua ntej nqus dej, yog li nws muaj kev ncua zoo, thiab vim nws yog cov hmoov uas muaj qhov loj me me, nws txawv ntawm lwm cov hmoov hauv txheej. qhov system.Lub cev muaj qhov tsis zoo.Tsis tas li ntawd, thaum tsim kev ncua, nws tuaj yeem tsav lwm cov hmoov los tsim cov nyhuv anti-stratification, yog li nws tseem ceeb heev los txhim kho kev ruaj ntseg ntawm lub kaw lus.
Tab sis ntau sodium-based bentonites hloov los ntawm calcium-based bentonite los ntawm kev hloov pauv sodium.Nyob rau tib lub sijhawm ntawm sodiumization, ntau cov ions zoo xws li calcium ions thiab sodium ions yuav raug tsim.Yog hais tias cov ntsiab lus ntawm cov cations nyob rau hauv lub system yog siab dhau lawm, ib tug loj npaum li cas ntawm tus nqi neutralization yuav raug generated ntawm cov nqi tsis zoo nyob rau saum npoo ntawm lub emulsion, yog li ntawd, nws yuav ua rau muaj kev phiv xws li o thiab flocculation ntawm. lub emulsion.Ntawm qhov tod tes, cov calcium ions no tseem yuav muaj kev phiv ntawm sodium ntsev dispersant (los yog polyphosphate dispersant), ua rau cov dispersants mus rau hauv lub txheej txheej txheej, nws thiaj li ua rau poob ntawm dispersion, ua rau lub txheej thicker, thicker los yog txawm. tuab dua.Muaj nag lossis daus loj thiab flocculation tshwm sim.Tsis tas li ntawd, cov nyhuv thickening ntawm bentonite tsuas yog tso siab rau cov hmoov kom nqus dej thiab nthuav dav los tsim kev ncua, yog li nws yuav ua rau cov nyhuv thixotropic muaj zog rau cov txheej txheem txheej txheej, uas yog qhov tsis zoo rau cov txheej txheem uas yuav tsum tau muaj cov teebmeem zoo.Yog li ntawd, bentonite inorganic thickeners yog tsis tshua muaj siv nyob rau hauv cov xim latex, thiab tsuas yog ib tug me me npaum li cas yog siv los ua thickeners nyob rau hauv qis-qib latex xim los yog txhuam latex xim.Txawm li cas los xij, nyob rau xyoo tas los no, qee cov ntaub ntawv tau pom tias Hemmings 'BENTONE®LT.organically hloov thiab refined hectorite muaj zoo anti-sedimentation thiab atomization teebmeem thaum siv rau latex xim airless txau tshuab.
(2) Cellulose ether:
Cellulose ether yog lub ntuj siab polymer tsim los ntawm condensation ntawm β-glucose.Siv cov yam ntxwv ntawm pawg hydroxyl hauv lub nplhaib glucosyl, cellulose tuaj yeem ua rau muaj ntau yam kev cuam tshuam los tsim cov derivatives.Ntawm lawv, esterification thiab etherification cov tshuaj tiv thaiv tau txais.Cov cellulose ester lossis cellulose ether derivatives yog cov cellulose derivatives tseem ceeb tshaj plaws.Cov khoom siv feem ntau yog carboxymethyl cellulose,hydroxyethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose thiab lwm yam.Vim tias carboxymethyl cellulose muaj sodium ions uas yooj yim soluble hauv dej, nws muaj cov dej tsis zoo, thiab cov khoom siv ntawm nws cov saw tseem ceeb yog me me, yog li nws yooj yim decomposed los ntawm cov kab mob corrosion, txo cov viscosity ntawm aqueous tov thiab ua rau nws. Tsis hnov tsw, thiab lwm yam phenomenon, tsis tshua muaj siv nyob rau hauv latex xim, feem ntau yog siv nyob rau hauv qis-qib polyvinyl cawv kua nplaum xim thiab putty.Cov dej dissolution tus nqi ntawm methylcellulose feem ntau qis dua li ntawm hydroxyethylcellulose.Tsis tas li ntawd, tej zaum yuav muaj ib qho me me ntawm cov teeb meem insoluble thaum lub sij hawm dissolution txheej txheem, uas yuav cuam tshuam rau cov tsos thiab kev xav ntawm txheej zaj duab xis, yog li nws yog tsis tshua muaj siv nyob rau hauv latex xim.Txawm li cas los xij, qhov nro ntawm cov tshuaj methyl aqueous yog me ntsis qis dua li ntawm lwm cov tshuaj cellulose aqueous, yog li nws yog ib qho zoo cellulose thickener siv hauv putty.Hydroxypropyl methylcellulose kuj yog cov cellulose thickener dav siv nyob rau hauv lub tshav pob ntawm putty, thiab tam sim no tsuas yog siv nyob rau hauv cement-based los yog txiv qaub-calcium-based putty (los yog lwm yam inorganic binders).Hydroxyethyl cellulose yog dav siv nyob rau hauv latex xim tshuab vim nws zoo solubility thiab dej tuav.Piv nrog rau lwm cov celluloses, nws muaj tsawg dua ntawm cov txheej txheem ua yeeb yaj kiab.Qhov zoo ntawm hydroxyethyl cellulose muaj xws li kev siv dej siab, kev sib raug zoo, kev ruaj ntseg zoo, thiab zoo pH stability ntawm viscosity.Qhov tsis zoo yog qhov tsis zoo ntawm cov dej ntws tsis zoo thiab tsis zoo cuam tshuam tsis zoo.Txhawm rau txhim kho cov kev tsis txaus no, kev hloov kho hydrophobic tau tshwm sim.Sex-associated hydroxyethylcellulose (HMHEC) xws li NatrosolPlus330, 331
(3) Polycarboxylates:
Nyob rau hauv no polycarboxylate, lub siab molecular hnyav yog ib tug thickener, thiab qhov tsawg molecular hnyav yog ib tug dispersant.Lawv tsuas yog adsorb dej molecules nyob rau hauv lub ntsiab saw ntawm lub system, uas ua rau kom lub viscosity ntawm dispersed theem;Tsis tas li ntawd, lawv kuj tseem tuaj yeem raug adsorbed rau ntawm qhov chaw ntawm cov khoom siv latex los tsim cov txheej txheej txheej, uas ua rau kom qhov loj me ntawm cov latex, ua kom cov hydration txheej ntawm cov latex, thiab ua kom cov viscosity ntawm cov theem sab hauv ntawm cov latex.Txawm li cas los xij, hom thickener no muaj qhov ua haujlwm qis qis, yog li nws maj mam tshem tawm hauv daim ntawv thov txheej.Tam sim no hom thickener no tsuas yog siv nyob rau hauv thickening ntawm cov xim muab tshuaj txhuam, vim hais tias nws molecular hnyav kuj loj, yog li nws yuav pab tau rau dispersibility thiab cia stability ntawm xim paste.
(4) Alkali-swellable thickener:
Muaj ob lub ntsiab ntawm alkali-swellable thickeners: zoo tib yam alkali-swellable thickeners thiab associative alkali-swellable thickeners.Qhov sib txawv loj tshaj plaws ntawm lawv yog qhov sib txawv ntawm cov monomers txuam nrog hauv cov saw tseem ceeb molecular.Associative alkali-swellable thickeners yog copolymerized nrog associative monomers uas muaj peev xwm adsorb ib leeg nyob rau hauv lub ntsiab saw qauv, yog li tom qab ionization nyob rau hauv aqueous tov, intra-molecular los yog inter-molecular adsorption yuav tshwm sim, ua rau lub viscosity ntawm lub system nce sai heev.
ib.Ordinary alkali-swellable thickener:
Tus neeg sawv cev ntawm cov khoom tseem ceeb ntawm cov alkali-swellable thickener yog ASE-60.ASE-60 feem ntau yog siv cov copolymerization ntawm methacrylic acid thiab ethyl acrylate.Thaum lub sij hawm copolymerization txheej txheem, methacrylic acid suav txog li 1/3 ntawm cov khoom siv, vim tias muaj cov carboxyl pawg ua rau cov saw hlau molecular muaj qee qhov dej ntawm hydrophilicity, thiab neutralizes cov txheej txheem ntsev.Vim lub repulsion ntawm tsub nqi, lub molecular chains yog nthuav, uas tsub kom lub viscosity ntawm lub system thiab ua ib tug thickening nyhuv.Txawm li cas los xij, qee zaum qhov hnyav molecular loj dhau vim qhov kev txiav txim ntawm tus neeg sawv cev sib txuas.Thaum lub sij hawm kev nthuav dav ntawm cov saw hlau molecular, cov saw hlau molecular tsis zoo dispersed nyob rau lub sij hawm luv luv.Thaum lub sij hawm ntev cia txheej txheem, cov saw molecular yog maj stretched, uas coj Post-thickening ntawm viscosity.Tsis tas li ntawd, vim tias muaj ob peb hydrophobic monomers nyob rau hauv cov saw hlau molecular ntawm hom thickener, nws tsis yooj yim los tsim hydrophobic complexation ntawm molecules, feem ntau yog ua kom intramolecule kev sib nrig sib adsorption, yog li no hom ntawm thickener muaj tsawg thickening efficiency, yog li nws yog. tsis tshua siv ib leeg.Nws yog tsuas yog siv ua ke nrog lwm cov thickeners.
b.Kev sib koom tes (concord) hom alkali swelling thickener:
Qhov no hom ntawm thickener tam sim no muaj ntau ntau yam vim hais tias ntawm kev xaiv ntawm associative monomers thiab tsim ntawm molecular qauv.Nws cov qauv saw tseem ceeb kuj tseem muaj cov methacrylic acid thiab ethyl acrylate, thiab cov koom haum monomers zoo li cov kav hlau txais xov hauv cov qauv, tab sis tsuas yog me me ntawm kev faib khoom.Nws yog cov koom haum monomers zoo li octopus tentacles uas ua lub luag haujlwm tseem ceeb tshaj plaws hauv kev ua kom zoo ntawm cov thickener.Cov pawg carboxyl nyob rau hauv cov qauv yog nruab nrab thiab ntsev-tsim, thiab cov saw molecular kuj zoo li ib tug dog dig alkali-swellable thickener.Tib yam nqi repulsion tshwm sim, kom cov saw molecular unfolds.Lub koom haum monomer nyob rau hauv nws kuj nthuav nrog cov saw molecular, tab sis nws cov qauv muaj ob qho tib si hydrophilic chains thiab hydrophobic chains, yog li ib tug loj micellar qauv zoo li surfactants yuav tsim nyob rau hauv lub molecule los yog ntawm molecules.Cov micelles no yog tsim los ntawm kev sib nrig sib adsorption ntawm koom haum monomers, thiab ib co koom haum monomers adsorb ib leeg los ntawm cov bridging nyhuv ntawm emulsion hais (los yog lwm yam hais).Tom qab cov micelles raug tsim, lawv kho cov emulsion hais, dej molecule particles los yog lwm yam hais nyob rau hauv lub system nyob rau hauv ib tug zoo li qub lub xeev zoo li lub enclosure txav, kom lub zog ntawm cov molecules (los yog hais) yog tsis muaj zog thiab viscosity ntawm cov khoom. system nce.Yog li ntawd, cov thickening efficiency ntawm no hom ntawm thickener, tshwj xeeb tshaj yog nyob rau hauv cov xim latex nrog siab emulsion cov ntsiab lus, yog nyob deb superior rau cov dog dig alkali-swellable thickeners, yog li nws yog dav siv nyob rau hauv latex xim.Tus neeg sawv cev ntawm cov khoom tseem ceeb Hom yog TT-935.
(5) Associative polyurethane (los yog polyether) thickening thiab leveling tus neeg sawv cev:
Feem ntau, cov thickeners muaj qhov hnyav heev molecular (xws li cellulose thiab acrylic acid), thiab lawv cov chains molecular yog stretched nyob rau hauv aqueous tov kom viscosity ntawm lub system.Qhov hnyav molecular ntawm polyurethane (los yog polyether) yog qhov me me, thiab nws feem ntau tsim kev koom tes los ntawm kev sib cuam tshuam ntawm van der Waals quab yuam ntawm lipophilic ntu ntawm cov molecules, tab sis lub koom haum quab yuam no tsis muaj zog, thiab lub koom haum tuaj yeem ua raws li qee yam. zog sab nraud.Kev sib cais, yog li txo cov viscosity, yog qhov tsim nyog rau kev sib cais ntawm cov yeeb yaj kiab txheej, yog li nws tuaj yeem ua lub luag haujlwm ntawm tus neeg sawv cev leveling.Thaum lub zog shear raug tshem tawm, nws tuaj yeem rov qab sib koom ua ke sai sai, thiab cov viscosity ntawm lub cev nce.Qhov tshwm sim no tau txais txiaj ntsig los txo cov viscosity thiab nce qib thaum tsim kho;thiab tom qab lub shear quab yuam ploj lawm, lub viscosity yuav rov qab tam sim ntawd kom cov thickness ntawm txheej txheej.Hauv kev siv tswv yim, peb muaj kev txhawj xeeb ntau ntxiv txog cov nyhuv thickening ntawm xws li associative thickeners ntawm polymer emulsions.Lub ntsiab polymer latex hais kuj koom nyob rau hauv lub koom haum ntawm lub system, thiaj li hais tias qhov no hom ntawm thickening thiab leveling tus neeg saib xyuas kuj muaj ib tug zoo thickening (los yog leveling) nyhuv thaum nws yog qis dua nws cov ntsiab lus tseem ceeb;Thaum lub concentration ntawm no hom thickening thiab leveling tus neeg sawv cev Thaum nws siab tshaj nws cov ntsiab lus tseem ceeb nyob rau hauv cov dej ntshiab, nws muaj peev xwm tsim kev koom tes ntawm nws tus kheej, thiab cov viscosity nce sai heev.Yog li ntawd, thaum zoo li no ntawm thickening thiab leveling tus neeg saib xyuas yog qis dua nws cov ntsiab lus tseem ceeb, vim hais tias cov latex hais koom nyob rau hauv ib feem kev koom tes, qhov me me particle loj ntawm emulsion, lub koom haum muaj zog, thiab nws viscosity yuav nce ntxiv nrog rau qhov nce ntawm cov emulsion. tus nqi ntawm emulsion.Tsis tas li ntawd, qee qhov dispersants (los yog acrylic thickeners) muaj cov qauv hydrophobic, thiab lawv pawg hydrophobic cuam tshuam nrog cov polyurethane, kom lub kaw lus tsim ib lub network loj, uas yog qhov zoo rau thickening.
2. Cov teebmeem ntawm cov thickeners sib txawv ntawm cov dej sib cais ua haujlwm ntawm cov xim latex
Nyob rau hauv kev tsim qauv ntawm cov xim pleev xim dej, kev siv cov thickeners yog qhov txuas tseem ceeb heev, uas muaj feem xyuam rau ntau yam khoom ntawm cov xim latex, xws li kev tsim kho, kev tsim xim, kev khaws cia thiab cov tsos.Ntawm no peb tsom mus rau qhov cuam tshuam ntawm kev siv cov thickeners ntawm kev khaws cov xim latex.Los ntawm cov lus qhia saum toj no, peb tuaj yeem paub tias bentonite thiab polycarboxylates: thickeners feem ntau yog siv rau hauv qee qhov tshwj xeeb coatings, uas yuav tsis tham txog ntawm no.Peb yuav tham txog cov feem ntau siv cellulose, alkali o, thiab Polyurethane (los yog polyether) thickeners, ib leeg thiab ua ke, cuam tshuam cov dej sib cais tsis kam ntawm cov xim latex.
Txawm hais tias thickening nrog hydroxyethyl cellulose ib leeg yog hnyav dua nyob rau hauv dej sib cais, nws yog ib qho yooj yim rau do tusyees.Kev siv ib zaug ntawm alkali o o thickening tsis muaj dej sib cais thiab nag lossis daus tab sis hnyav hnyav tom qab thickening.Kev siv ib leeg ntawm polyurethane thickening, txawm tias dej sib cais thiab tom qab thickening Lub thickening tsis loj, tab sis cov precipitate ua los ntawm nws yog ib qho nyuaj thiab nyuaj rau do.Thiab nws txais yuav hydroxyethyl cellulose thiab alkali o o thickening compound, tsis muaj post-thickening, tsis nyuaj los nag, yooj yim rau do, tab sis kuj muaj me me dej.Txawm li cas los xij, thaum hydroxyethyl cellulose thiab polyurethane siv los ua kom tuab, kev sib cais dej yog qhov hnyav tshaj plaws, tab sis tsis muaj nag lossis daus nyuaj.Alkali-swellable thickening thiab polyurethane yog siv ua ke, txawm hais tias cov dej sib cais yog qhov yooj yim tsis muaj dej sib cais, tab sis tom qab thickening, thiab cov sediment hauv qab yog nyuaj rau do tusyees.Thiab qhov kawg siv ib qho me me ntawm hydroxyethyl cellulose nrog alkali o thiab polyurethane thickening kom muaj lub xeev zoo li tsis muaj nag lossis daus thiab dej sib cais.Nws tuaj yeem pom tau tias nyob rau hauv cov ntshiab acrylic emulsion system nrog muaj zog hydrophobicity, nws yog qhov hnyav dua kom thicken cov dej theem nrog hydrophilic hydroxyethyl cellulose, tab sis nws tuaj yeem ua tau yooj yim stirred tusyees.Kev siv ib leeg ntawm hydrophobic alkali o thiab polyurethane (los yog lawv cov compound) thickening, txawm hais tias cov dej sib cais ua haujlwm zoo dua, tab sis ob qho tib si thicken tom qab, thiab yog tias muaj nag lossis daus, nws yog hu ua nag lossis daus nyuaj, uas nyuaj rau do tusyees.Kev siv cellulose thiab polyurethane compound thickening, vim qhov deb tshaj qhov sib txawv ntawm hydrophilic thiab lipophilic qhov tseem ceeb, ua rau cov dej sib cais thiab nag lossis daus loj tshaj plaws, tab sis cov sediment yog mos thiab yooj yim rau do.Cov qauv kawg muaj qhov zoo tshaj plaws los tiv thaiv dej sib cais vim qhov sib npaug zoo ntawm hydrophilic thiab lipophilic.Ntawm chav kawm, nyob rau hauv cov txheej txheem tsim qauv, hom emulsions thiab ntub dej thiab dispersing agents thiab lawv cov hydrophilic thiab lipophilic qhov tseem ceeb yuav tsum tau txiav txim siab.Tsuas yog thaum lawv ncav cuag qhov sib npaug zoo, lub kaw lus tuaj yeem nyob rau hauv lub xeev ntawm thermodynamic equilibrium thiab muaj dej tsis kam.
Nyob rau hauv lub thickening system, lub thickening ntawm cov dej theem yog qee zaum nrog kev nce ntawm viscosity ntawm cov roj theem.Piv txwv li, peb feem ntau ntseeg hais tias cellulose thickeners thicken cov dej theem, tab sis cov cellulose faib nyob rau hauv dej theem.
Post lub sij hawm: Dec-29-2022