1. Inkcazo kunye nomsebenzi we-thickener
Izongezo ezinokwandisa kakhulu i-viscosity yeepeyinti ezisekelwe emanzini zibizwa ngokuba yi-thickeners.
I-Thickeners idlala indima ebalulekileyo kwimveliso, ukugcinwa kunye nokwakhiwa kweengubo.
Umsebenzi oyintloko we-thickener kukwandisa i-viscosity yokugqoka ukuhlangabezana neemfuno zezigaba ezahlukeneyo zokusetyenziswa. Nangona kunjalo, i-viscosity efunwa yi-coating kumanqanaba ahlukeneyo yahlukile. Umzekelo:
Ngexesha lokugcinwa kwenkqubo, kuyinqweneleka ukuba ne-viscosity ephezulu ukukhusela i-pigment ukuba ihlale;
Ngexesha lenkqubo yokwakha, kuyinqweneleka ukuba ne-viscosity ephakathi ukuqinisekisa ukuba ipeyinti ine-brushability efanelekileyo ngaphandle kokugqithiswa kwepeyinti egqithisileyo;
Emva kokwakhiwa, kuyathenjwa ukuba i-viscosity inokukhawuleza ibuyele kwi-viscosity ephezulu emva kwexesha elifutshane (inkqubo yokulinganisa) ukukhusela ukuchithwa.
Ubumanzi bokugquma kwamanzi abuyiyo iNewtonian.
Xa i-viscosity yepeyinti iyancipha ngokunyuka kwamandla e-shear, ibizwa ngokuba yi-pseudoplastic fluid, kwaye ininzi yepeyinti i-pseudoplastic fluid.
Xa ukuziphatha okuhambayo kwe-pseudoplastic fluid kuhambelana nembali yayo, oko kukuthi, kuxhomekeke kwixesha, kubizwa ngokuba yi-thixotropic fluid.
Xa kuveliswa iingubo, sihlala sizama ngokunyanisekileyo ukwenza iingubo ze-thixotropic, ezinjengokongeza izongezo.
Xa i-thixotropy yokugqoka ifanelekile, inokusombulula ukuchasana kwezigaba ezahlukahlukeneyo zokugqoka, kwaye ihlangabezane neemfuno zobugcisa be-viscosity eyahlukeneyo yokugqoka kwindawo yokugcina, ukwakhiwa komgangatho, kunye nezigaba zokumisa.
Ezinye i-thickeners zinokunika ipeyinti nge-thixotropy ephezulu, ukwenzela ukuba ibe ne-viscosity ephezulu ekuphumleni okanye kwizinga eliphantsi lokucheba (njengokugcina okanye ukuthutha), ukwenzela ukukhusela i-pigment kwipeyinti ukuba ihlale. Kwaye phantsi kwesantya esiphezulu se-shear (njengenkqubo yokugubungela), ine-viscosity ephantsi, ukwenzela ukuba i-coating inompompo owaneleyo kunye nokulinganisa.
Thixotropy imelwe yi-thixotropic index TI kwaye ilinganiswe yi-viscometer ye-Brookfield.
I-TI = i-viscosity (ilinganiswe kwi-6r / min) / i-viscosity (ilinganiswe kwi-60r / min)
2. Iintlobo ze-thickeners kunye nemiphumo yazo kwiipropati zokugqoka
(1) Iindidi Ngokumalunga nokwakheka kweekhemikhali, i-thickeners yahlulwe yangamacandelo amabini: i-organic and inorganic.
Iintlobo ze-Inorganic ziquka i-bentonite, i-attapulgite, i-aluminium magnesium silicate, i-lithium magnesium silicate, njl., iintlobo zezinto eziphilayo ezifana ne-methyl cellulose, i-hydroxyethyl cellulose, i-polyacrylate, i-polymethacrylate, i-acrylic acid okanye i-methyl Acrylic homopolymer okanye i-copolymer kunye ne-polyurethane njl.
Ukususela kumbono wempembelelo kwiipropati ze-rheological of coatings, i-thickeners ihlulwe ibe yi-thixotropic thickeners kunye ne-associative thickeners. Ngokweemfuno zokusebenza, ubungakanani be-thickener kufuneka bube buncinci kwaye umphumo wokuqina ulungile; akukho lula ukutshatyalaliswa yi-enzymes; xa iqondo lokushisa okanye ixabiso le-pH lenkqubo litshintsha, i-viscosity yokugqoka ayiyi kuncitshiswa kakhulu, kwaye i-pigment kunye ne-filler ayiyi kuhluthwa. ; Uzinzo oluhle lokugcina; ukugcinwa kakuhle kwamanzi, akukho nto icacileyo yegwebu kwaye akukho miphumo emibi ekusebenzeni kwefilimu yokugqoka.
① Isityebi seCellulose
I-cellulose thickeners esetyenziswa kwiingubo ubukhulu becala yi-methylcellulose, i-hydroxyethylcellulose kunye ne-hydroxypropylmethylcellulose, kwaye ezimbini zokugqibela zisetyenziswa kakhulu.
I-Hydroxyethyl cellulose yimveliso efunyenwe ngokutshintshwa kwamaqela e-hydroxyl kwiiyunithi ze-glucose ze-cellulose yendalo kunye namaqela e-hydroxyethyl. Ukucaciswa kunye neemodeli zeemveliso zihlukaniswa ngokukodwa ngokwezinga lokutshintshwa kunye ne-viscosity.
Iindidi ze-hydroxyethyl cellulose zikwahlulwe ngohlobo oluqhelekileyo lokuchithwa, uhlobo lokusasazeka ngokukhawuleza kunye nohlobo lozinzo lwebhayoloji. Ngokubhekiselele kwindlela yokusetyenziswa, i-hydroxyethyl cellulose inokongezwa kwizigaba ezahlukeneyo kwinkqubo yokuvelisa i-coating. Uhlobo lokusabalalisa ngokukhawuleza lunokongezwa ngokuthe ngqo ngendlela yomgubo owomileyo. Nangona kunjalo, ixabiso le-pH yenkqubo ngaphambi kokuba udibanise kufuneka libe ngaphantsi kwe-7, ngokukodwa ngenxa yokuba i-cellulose ye-hydroxyethyl inyibilika ngokucothayo kwixabiso eliphantsi le-pH, kwaye kukho ixesha elaneleyo lokuba amanzi angene ngaphakathi kwamasuntswana, kwaye ke ixabiso le-pH linyuswe ukuze liyenze i-Dissolids ngokukhawuleza. Amanyathelo ahambelanayo nawo angasetyenziselwa ukulungiselela i-concentration ethile yesisombululo seglue kwaye uyongeze kwinkqubo yokugqoka.
IHydroxypropyl methylcelluloseyimveliso efunyenwe ngokutshintsha iqela le-hydroxyl kwiyunithi ye-glucose ye-cellulose yendalo kunye neqela le-methoxy, ngelixa enye inxalenye ithatyathwa liqela le-hydroxypropyl. Isiphumo salo sokuqina siyafana neso se-hydroxyethyl cellulose. Kwaye iyamelana nokuthotywa kwe-enzymatic, kodwa ukunyibilika kwayo kwamanzi akulunganga njengaleyo ye-hydroxyethyl cellulose, kwaye ine-disadvantage ye-gelling xa ishushu. Kwi-surface-treated hydroxypropyl methylcellulose, inokongezwa ngokuthe ngqo emanzini xa isetyenziswa. Emva kokuvuselela kunye nokusabalalisa, yongeza izinto ze-alkaline ezifana namanzi e-ammonia ukulungelelanisa ixabiso le-pH kwi-8-9, kwaye udibanise de uchithe ngokupheleleyo. Kwi-hydroxypropyl methylcellulose ngaphandle konyango lomphezulu, inokuxutywa kwaye idumbe ngamanzi ashushu ngaphezu kwe-85 ° C ngaphambi kokusetyenziswa, kwaye emva koko ipholile kwiqondo lokushisa, emva koko ixutywe ngamanzi abandayo okanye amanzi e-ice ukuze ichithe ngokupheleleyo.
②I-Inorganic thickener
Olu hlobo lwe-thickener luyimveliso yodongwe olusebenzayo, njenge-bentonite, i-magnesium aluminium silicate udongwe, njl. Emva kokuba i-coating yomisiwe kwaye yenziwe ifilimu, yenza njengento yokuzalisa ifilimu yokugqoka, njl njl. Into engathandekiyo kukuba iya kuchaphazela kakhulu umgangatho wokulinganisa.
③ Isityebi sepolymer esenziweyo
I-Synthetic polymer thickeners isetyenziswa kakhulu kwi-acrylic kunye ne-polyurethane (i-associative thickeners). I-Acrylic thickeners ubukhulu becala ziipolima ze-acrylic eziqulathe amaqela e-carboxyl. Emanzini anexabiso le-pH ye-8-10, iqela le-carboxyl liyahlukana kwaye livuvukale; xa ixabiso le-pH likhulu kune-10, lichithwa emanzini kwaye lilahlekelwa yimpembelelo yokuqina, ngoko umphumo wokuqina unzima kakhulu kwixabiso le-pH.
Indlela yokuqina ye-acrylate thickener kukuba amasuntswana alo angabhengezwa kumphezulu we-latex kwipeyinti, kwaye enze umaleko wokugquma emva kokudumba kwealkali, okwandisa umthamo we-latex particles, ithintele intshukumo yeBrownian yamasuntswana, kwaye yandise i-viscosity yenkqubo yepeyinti. ; Okwesibini, ukuvuvukala kwe-thickener kwandisa i-viscosity yesigaba samanzi.
(2) Impembelelo ye-thickener kwiipropati zokugquma
Isiphumo sohlobo lwe-thickener kwiipropathi zerheological zokugquma zimi ngolu hlobo lulandelayo:
Xa isixa se-thickener sinyuka, i-viscosity ye-static yepeyinti iyanda kakhulu, kwaye i-viscosity yokutshintsha i-trend ihambelana ngokusisiseko xa iphantsi kwamandla angaphandle okucheba.
Ngempembelelo ye-thickener, i-viscosity yepeyinti iyancipha ngokukhawuleza xa iphantsi kwamandla okucheba, ebonisa i-pseudoplasticity.
Ukusebenzisa i-hydrophobically modified cellulose thickener (efana ne-EBS451FQ), kumazinga aphezulu okucheba, i-viscosity isephezulu xa isixa sikhulu.
Ukusebenzisa i-associative polyurethane thickeners (njenge-WT105A), kumazinga aphezulu okucheba, i-viscosity isephezulu xa isixa sikhulu.
Ukusebenzisa i-acrylic thickeners (njenge-ASE60), nangona i-viscosity ye-static iphakama ngokukhawuleza xa isixa sikhulu, i-viscosity iyancipha ngokukhawuleza kwizinga eliphezulu lokucheba.
3. I-Associative thickener
(1) indlela yokujiya
I-ether ye-cellulose kunye ne-alkali-swellable thickeners ye-acrylic inokunyusa kuphela isigaba samanzi, kodwa ayinayo impembelelo yokuqina kwamanye amacandelo kwipeyinti esekwe emanzini, kwaye ayinakubangela ukusebenzisana okubalulekileyo phakathi kwee-pigments kwipeyinti kunye namasuntswana e-emulsion, ngoko ke I-rheology yepeyinti ayikwazi ukulungiswa.
I-Associative thickeners ibonakaliswe ekubeni ngaphezu kokuqina ngokusebenzisa i-hydration, iphinda idibanise ngokudibanisa phakathi kwabo, kunye namasuntswana ahlakazekileyo, kunye namanye amacandelo kwinkqubo. Lo mbutho uyahlukana kumazinga aphezulu okucheba kwaye uphinde udibanise kumazinga aphantsi okucheba, okuvumela ukuba i-rheology yokwambathisa ilungiswe.
Indlela yokuqina ye-asociative thickener kukuba i-molecule yayo yi-linear hydrophilic chain, i-polymer compound enamaqela e-lipophilic kuzo zombini iziphelo, oko kukuthi, inamaqela e-hydrophilic kunye ne-hydrophobic kwisakhiwo, ngoko ke ineempawu ze-molecule ze-surfactant. indalo. Iimolekyuli ezinjalo ze-thickener azikwazi nje ukukhupha amanzi kunye nokudumba ukujiya isigaba samanzi, kodwa zenze ii-micelles xa ukuxinwa kwesisombululo saso samanzi kudlula ixabiso elithile. I-micelles inokudibanisa kunye ne-polymer particles ye-emulsion kunye ne-pigment particles eziye zabhengeza i-dispersant ukuze zenze isakhiwo sothungelwano esine-dimensional ezintathu, kwaye zidibaniswe kwaye zidibaniswe ukwandisa i-viscosity yenkqubo.
Okubaluleke ngakumbi kukuba le mibutho ikwimo yolungelelwaniso oluguquguqukayo, kwaye ezo micelles ezinxulumene nazo zinokuhlengahlengisa izikhundla zazo xa ziphantsi kwamandla angaphandle, ukuze i-coating ineempawu zokulinganisa. Ukongezelela, ekubeni i-molecule inama-micelles amaninzi, esi sakhiwo sinciphisa ukuthambekela kwee-molecule zamanzi ukuba zifuduke kwaye ngoko kwandisa i-viscosity yesigaba samanzi.
(2) Indima yokwaleka
Uninzi lwee-asociative thickeners zi-polyurethanes, kwaye ubunzima babo bemolekyuli buphakathi kwe-103-104 yee-odolo zobukhulu, ii-odolo ezimbini zobukhulu obungaphantsi kune-polyacrylic acid eqhelekileyo kunye ne-cellulose thickeners kunye nobunzima bemolekyuli phakathi kwe-105-106. Ngenxa yobunzima obuphantsi bemolekyuli, ukunyuka kwevolumu esebenzayo emva kokuba i-hydration ingaphantsi, ngoko ke i-viscosity curve yayo ilula kune-non-associative thickeners.
Ngenxa yobunzima be-molecular of the thickener associative, ukudibanisa kwayo i-intermolecular kwisigaba samanzi kunqunyelwe, ngoko ke umphumo wayo wokuqina kwinqanaba lamanzi awubalulekanga. Kwinqanaba eliphantsi lereyithi ye-shear, ukuguqulwa kombutho phakathi kweeamolekyu kungaphezulu kokutshatyalaliswa kobudlelwane phakathi kweeamolekyu, yonke inkqubo igcina ukumiswa okungokwemvelo kunye nokusabalalisa, kwaye i-viscosity isondele kwi-viscosity ye-dispersion medium (amanzi). Ke ngoko, i-associative thickener yenza inkqubo yepeyinti esekwe emanzini ibonise i-viscosity ephantsi ebonakalayo xa ikwindawo ephantsi yezinga lokucheba.
I-Associative thickeners yandisa amandla anokubakho phakathi kweamolekyu ngenxa yobudlelwane phakathi kwamaqhekeza kwisigaba esisasazekayo. Ngale ndlela, amandla amaninzi afunekayo ukuphula unxulumano phakathi kweemolekyuli kumazinga aphezulu okucheba, kwaye amandla okucheba afunekayo ukufezekisa uhlobo olufanayo lokucheba nawo mkhulu, ukuze inkqubo ibonise izinga eliphezulu lokucheba kumazinga aphezulu okucheba. I-viscosity ebonakalayo. I-viscosity ephezulu ye-shear ephezulu kunye ne-low-chear viscosity ephantsi inokwenza nje ukungabikho kwezinto eziqhelekileyo eziqhelekileyo kwiipropati ze-rheological zepeyinti, oko kukuthi, i-thickeners ezimbini zingasetyenziselwa ukudibanisa ukulungelelanisa i-fluidity yepeyinti ye-latex. Ukusebenza okuguquguqukayo, ukuhlangabezana neemfuno ezibanzi zokugquma kwifilimu eshinyeneyo kunye nokuhamba kwefilimu.
Ixesha lokuposa: Apr-28-2024