1. Inkcazo kunye nomsebenzi wesithambisi
Izinto ezongeziweyo ezinokunyusa kakhulu ubungqindilili beepeyinti ezisekelwe emanzini zibizwa ngokuba zizinto ezithibazayo.
Izinto zokutyebisa zidlala indima ebalulekileyo ekuvelisweni, ekugcinweni nasekukhiweni kweengubo zokugquma.
Umsebenzi oyintloko wesithambisi kukwandisa ubungqindilili bengubo ukuze ihlangabezane neemfuno zamanqanaba ahlukeneyo okusetyenziswa. Nangona kunjalo, ubungqindilili obufunekayo yingubo kumanqanaba ahlukeneyo buhlukile. Umzekelo:
Ngexesha lenkqubo yokugcina, kuyacetyiswa ukuba kubekho i-viscosity ephezulu ukuthintela ukuba umbala ungahlali;
Ngexesha lenkqubo yokwakha, kuyacetyiswa ukuba ipeyinti ibe nobukhulu obuphakathi ukuqinisekisa ukuba ipeyinti iyakwazi ukuxukuxwa kakuhle ngaphandle kokufaka idayi egqithisileyo yepeyinti;
Emva kokwakhiwa, kunethemba lokuba i-viscosity ingabuyela ngokukhawuleza kwi-viscosity ephezulu emva kwexesha elifutshane (inkqubo yokulinganisa) ukuthintela ukugoba.
Ukutyibilika kweengubo ezisetyenziswa emanzini akusiyo iNewtonian.
Xa i-viscosity yepeyinti incipha ngokonyuka kwamandla okucheba, ibizwa ngokuba yi-pseudoplastic fluid, kwaye uninzi lwepeyinti luyi-pseudoplastic fluid.
Xa indlela oluhamba ngayo ulwelo lwe-pseudoplastic inxulumene nembali yalo, oko kukuthi, luxhomekeke kwixesha, lubizwa ngokuba lulwelo lwe-thixotropic.
Xa sisenza izinto zokugquma, sidla ngokuzama ngabom ukwenza izinto zokugquma zibe yithixotropic, njengokongeza izongezo.
Xa i-thixotropy yengubo ifanelekile, inokusombulula ukungqubana kwezigaba ezahlukeneyo zengubo, kwaye ihlangabezane neemfuno zobugcisa ze-viscosity eyahlukileyo yengubo kwizigaba zokugcina, zokulinganisa ulwakhiwo, kunye nezokomisa.
Ezinye izinto zokutyebisa zinokunika ipeyinti i-thixotropy ephezulu, ukuze ibe ne-viscosity ephezulu xa iphumle okanye ngesantya esiphantsi sokucheba (njengokugcinwa okanye ukuthuthwa), ukuze kuthintelwe ukuba umbala kwipeyinti ungahlali. Kwaye phantsi kwesantya esiphezulu sokucheba (njengenkqubo yokugquma), ine-viscosity ephantsi, ukuze i-viscosity ibe nokuhamba kakuhle kunye nokulingana.
I-Thixotropy imelwe yi-thixotropic index TI kwaye ilinganiswa yiBrookfield viscometer.
I-TI=ukuxinana (kulinganiswa kwi-6r/min)/ukuxinana (kulinganiswa kwi-60r/min)
2. Iintlobo zezinto ezithibazayo kunye nefuthe lazo kwiimpawu zokugquma
(1) Iindidi Ngokuphathelele ukwakheka kweekhemikhali, izinto zokutyebisa zahlulwe zibe ziindidi ezimbini: ezi-organic nezingezizo ezi-organic.
Iintlobo ezingezizo zendalo ziquka i-bentonite, i-attapulgite, i-aluminium magnesium silicate, i-lithium magnesium silicate, njl.njl., iintlobo zendalo ezifana ne-methyl cellulose, i-hydroxyethyl cellulose, i-polyacrylate, i-polymethacrylate, i-acrylic acid okanye i-methyl. I-Acrylic homopolymer okanye i-copolymer kunye ne-polyurethane njl.njl.
Ngokwembono yempembelelo kwiimpawu ze-rheological zeengubo, ii-thickeners zahlulwe zibe zii-thickeners ze-thixotropic kunye nee-thickeners ezidibeneyo. Ngokweemfuno zokusebenza, ubungakanani be-thickener kufuneka bube mncinci kwaye isiphumo sokutyeba silungile; akulula ukutshabalala zii-enzymes; xa ubushushu okanye ixabiso le-pH lenkqubo litshintsha, i-viscosity yengubo ayizukuncipha kakhulu, kwaye i-pigment kunye ne-filler azizukususwa. ; Uzinzo oluhle lokugcina; ukugcinwa kwamanzi okuhle, akukho nto ibonakalayo yokugqwala kwaye akukho miphumo mibi ekusebenzeni kwefilimu yokugquma.
①Isinyibilikisi se-cellulose
Izinto zokuthina ze-cellulose ezisetyenziswa kwiingubo ikakhulu yi-methylcellulose, i-hydroxyethylcellulose kunye ne-hydroxypropylmethylcellulose, kwaye ezimbini zokugqibela zisetyenziswa kakhulu.
I-Hydroxyethyl cellulose yimveliso efunyenwe ngokutshintsha amaqela e-hydroxyl kwiiyunithi zeglucose ze-cellulose yendalo ngamaqela e-hydroxyethyl. Iinkcukacha kunye neemodeli zeemveliso zahlulwe kakhulu ngokwezinga lokutshintshwa kunye ne-viscosity.
Iindidi ze-hydroxyethyl cellulose nazo zahlulwe ngohlobo oluqhelekileyo lokunyibilika, uhlobo lokusasazeka ngokukhawuleza kunye nohlobo lokuzinza kwezinto eziphilayo. Ngokuphathelele indlela yokusebenzisa, i-hydroxyethyl cellulose inokongezwa kumanqanaba ahlukeneyo kwinkqubo yokuvelisa i-coating. Uhlobo olusasazeka ngokukhawuleza lunokongezwa ngokuthe ngqo ngendlela ye-powder eyomileyo. Nangona kunjalo, ixabiso le-pH lenkqubo ngaphambi kokongeza kufuneka libe ngaphantsi kwe-7, ikakhulu kuba i-hydroxyethyl cellulose inyibilika kancinci ngexabiso eliphantsi le-pH, kwaye kukho ixesha elaneleyo lokuba amanzi angene ngaphakathi kwamasuntswana, kwaye emva koko ixabiso le-pH liyanyuswa ukuze linyibilike ngokukhawuleza. Amanyathelo ahambelanayo anokusetyenziswa ukulungiselela uxinzelelo oluthile lwesisombululo seglue kwaye ulufake kwinkqubo ye-coating.
I-hydroxypropyl methylcelluloseyimveliso efunyenwe ngokutshintsha iqela le-hydroxyl kwiyunithi yeglucose ye-cellulose yendalo ngeqela le-methoxy, ngelixa elinye inxalenye lithathelwa indawo liqela le-hydroxypropyl. Isiphumo sayo sokutyeba sifana nese-hydroxyethyl cellulose. Kwaye ayimelani nokuwohloka kwe-enzyme, kodwa ukunyibilika kwayo emanzini akulunganga njengokwe-hydroxyethyl cellulose, kwaye ineengxaki ze-gelling xa ishushu. Kwi-hydroxypropyl methylcellulose ephathwe phezu komhlaba, ingongezwa ngqo emanzini xa isetyenziswa. Emva kokuyixuba nokuyichitha, yongeza izinto ze-alkaline ezifana namanzi e-ammonia ukulungisa ixabiso le-pH ukuya kwi-8-9, kwaye uyixube ide inyibilike ngokupheleleyo. Kwi-hydroxypropyl methylcellulose ngaphandle kokunyangwa komphezulu, ingamanziswa kwaye ivuvuke ngamanzi ashushu angaphezu kwama-85°C ngaphambi kokusetyenziswa, ize ipholiswe kubushushu begumbi, ize ixutywe ngamanzi abandayo okanye amanzi eqhwa ukuze iyinyibilike ngokupheleleyo.
②Isithambisi esingadalwanga
Olu hlobo lwesithambisi ikakhulu ziimveliso zodongwe ezisebenzayo, ezifana ne-bentonite, udongwe lwe-magnesium aluminium silicate, njl. Luphawulwa kukuba ukongeza kwisiphumo sokutyeba, lukwanomphumo omhle wokuxhoma, lunokuthintela ukuntywila, kwaye aluyi kuchaphazela ukumelana kwamanzi kwesithambisi. Emva kokuba isithambisi somile kwaye senziwe ifilimu, sisebenza njengesizalisi kwifilimu yesithambisi, njl. Into engathandekiyo kukuba siya kuchaphazela kakhulu ukulenzakala kwesithambisi.
③ Isithambisi sepolymer esenziwe ngokwenziwa
Izithambisi zepolymer ezenziwe ngokwenziwa zisetyenziswa kakhulu kwi-acrylic kunye ne-polyurethane (izithambisi ezidibeneyo). Izithambisi ze-acrylic ikakhulu zii-polymers ze-acrylic eziqulathe amaqela e-carboxyl. Emanzini anexabiso le-pH eliyi-8-10, iqela le-carboxyl liyahlukana kwaye lidumbe; xa ixabiso le-pH lingaphezulu kwe-10, liyanyibilika emanzini kwaye lilahlekelwe lifuthe lokutyeba, ngoko ke isiphumo sokutyeba sinovakalelo olukhulu kwixabiso le-pH.
Indlela yokwenza i-acrylate thickener ibe nkulu kukuba amasuntswana ayo anokufunxwa phezu kwamasuntswana e-latex kwipeyinti, aze enze umaleko wokugquma emva kokudumba kwe-alkali, nto leyo enyusa umthamo wamasuntswana e-latex, ithintele intshukumo ye-Brownian yamasuntswana, kwaye inyuse i-viscosity yenkqubo yepeyinti. ; Okwesibini, ukudumba kwe-thickener kwandisa i-viscosity yesigaba samanzi.
(2) Impembelelo yesithambisi kwiimpawu zokugquma
Impembelelo yohlobo lwe-thickener kwiipropati ze-rheological zengubo yile ilandelayo:
Xa ubungakanani be-thickener busanda, i-static viscosity yepeyinti iyanda kakhulu, kwaye utshintsho lwe-viscosity luhlala lufana xa lusetyenziswa ngamandla angaphandle okucheba.
Ngenxa yesiphumo se-thickener, i-viscosity yepeyinti yehla ngokukhawuleza xa isetyenziswa ngamandla okucheba, nto leyo ebonisa ukuba ayilunganga.
Ukusebenzisa i-hydrophobically modified cellulose thickener (efana ne-EBS451FQ), xa i-shear rates iphezulu, i-viscosity isephezulu xa ubungakanani bukhulu.
Ukusebenzisa izithambisi ze-polyurethane ezidityanisiweyo (ezifana ne-WT105A), xa zithe zagutyungelwa kakhulu, i-viscosity isephezulu xa ubungakanani bukhulu.
Ukusebenzisa izithambisi ze-acrylic (ezifana ne-ASE60), nangona i-viscosity engaguqukiyo inyuka ngokukhawuleza xa ubungakanani bukhulu, i-viscosity iyancipha ngokukhawuleza ngesantya esiphezulu sokucheba.
3. Isithambisi esidibeneyo
(1) indlela yokwenza utyebe
I-cellulose ether kunye ne-alkali-swelling acrylic thickeners zinokwenza i-water phase ibe nkulu kuphela, kodwa azinampembelelo yokuqina kwezinye izinto ezikwipeyinti esekwe emanzini, kwaye azinakubangela ukusebenzisana okubalulekileyo phakathi kweepigments ezikwipeyinti kunye namasuntswana e-emulsion, ngoko ke i-rheology yepeyinti ayinakulungiswa.
Izithambisi ezidityanisiweyo zibonakaliswa kukuba ukongeza ekuqineni ngenxa yokufuma, zikwakhula ngokusebenzisa ubudlelwane phakathi kwazo, kunye namasuntswana asasazekileyo, kunye nezinye izinto kwinkqubo. Olu nxulumano luyahlukana ngamanani aphezulu okucheba kwaye luphinde ludityaniswe ngamanani aphantsi okucheba, okuvumela ukuba i-rheology yengubo ilungiswe.
Indlela yokwenza i-associative thickener ibe nkulu kukuba i-molecule yayo yi-linear hydrophilic chain, i-polymer compound enamaqela e-lipophilic kuzo zombini iziphelo, oko kukuthi, ine-hydrophilic kunye ne-hydrophobic groups kwisakhiwo, ngoko ke ineempawu ze-surfactant molecules. Ezi molecule ze-thickener azinakuphela nje ngokufunxa nokudumba ukuze zijiye i-water phase, kodwa zenze nee-micelles xa uxinzelelo lwesisombululo sayo samanzi ludlula ixabiso elithile. Ii-micelles zinokunxulumana nee-polymer particles ze-emulsion kunye nee-pigment particles eziye zafunxa i-dispersant ukuze zenze isakhiwo senethiwekhi esinemilinganiselo emithathu, kwaye zidibene kwaye zibambene ukuze kwandiswe i-viscosity yenkqubo.
Okubaluleke ngakumbi kukuba ezi ntsebenziswano zikwimeko yokulinganisela okuguquguqukayo, kwaye ezo micelles zinxulumene nazo zinokulungisa iindawo zazo xa ziphantsi kwamandla angaphandle, ukuze uqweqwe lube neempawu zokulinganisa. Ukongeza, ekubeni imolekyuli ineemicelles ezininzi, olu lwakhiwo lunciphisa ukuthambekela kweemolekyuli zamanzi ukuba zifuduke kwaye ngaloo ndlela lwandise i-viscosity yesigaba samanzi.
(2) Indima ekugqunyweni
Uninzi lwezithina ezidityanisiweyo ziipolyurethanes, kwaye ubunzima bazo beemolekyuli buphakathi kwe-103-104 orders zobukhulu, ii-orders ezimbini zobukhulu zingaphantsi kune-polyacrylic acid eqhelekileyo kunye ne-cellulose thickeners ezinobunzima beemolekyuli obuphakathi kwe-105-106. Ngenxa yobunzima obuphantsi beemolekyuli, ukwanda komthamo osebenzayo emva kokufuma kuncinci, ngoko ke i-viscosity curve yayo ithambile kuneyezithina ezingezizo ezidityanisiweyo.
Ngenxa yobunzima obuphantsi beemolekyuli ze-associative thickener, ukuxinana kwayo phakathi kweemolekyuli kwisigaba samanzi kunqongophele, ngoko ke isiphumo sayo sokutyeba kwisigaba samanzi asibalulekanga. Kwinqanaba eliphantsi le-shear rate, ukuguqulwa kobudlelwane phakathi kweemolekyuli kungaphezulu kokutshatyalaliswa kobudlelwane phakathi kweemolekyuli, yonke inkqubo igcina imeko yokumisa kunye nokusasazeka, kwaye i-viscosity isondele kwi-viscosity ye-dispersion medium (amanzi). Ke ngoko, i-associative thickener yenza inkqubo yepeyinti esekelwe emanzini ibonise i-viscosity ephantsi ebonakalayo xa ikwindawo ye-shear rate ephantsi.
Izithambisi ezidityanisiweyo zonyusa amandla anokubakho phakathi kweemolekyuli ngenxa yobudlelwane phakathi kweesuntswana kwisigaba esisasazekileyo. Ngale ndlela, kufuneka amandla angakumbi ukuze kwaphulwe ubudlelwane phakathi kweemolekyuli ngamanani aphezulu okucheba, kwaye amandla okucheba afunekayo ukufezekisa uxinzelelo olufanayo lokucheba nawo makhulu, ukuze inkqubo ibonise izinga eliphezulu lokucheba ngamanani aphezulu okucheba. I-viscosity ebonakalayo. I-viscosity ephezulu yokucheba okuphezulu kunye ne-viscosity ephantsi yokucheba okuphantsi kunokulungisa nje ukungabikho kwezithambisi eziqhelekileyo kwiimpawu ze-rheological zepeyinti, oko kukuthi, izithambisi ezimbini zingasetyenziswa ngokudibeneyo ukulungisa ukugeleza kwepeyinti ye-latex. Ukusebenza okuguquguqukayo, ukuhlangabezana neemfuno ezipheleleyo zokugquma zibe yifilimu etyebileyo kunye nokuhamba kwefilimu yokugquma.
Ixesha leposi: Epreli-28-2024