1. Incazelo kanye nomsebenzi we-thickener
Izithasiselo ezingandisa kakhulu i-viscosity yamapende asekelwe emanzini abizwa ngokuthi ama-thickeners.
Ama-thickeners adlala indima ebalulekile ekukhiqizeni, ekugcinweni nasekwakheni ama-coatings.
Umsebenzi oyinhloko we-thickener ukwandisa i-viscosity ye-coating ukuze uhlangabezane nezidingo zezigaba ezahlukene zokusetshenziswa. Kodwa-ke, i-viscosity edingwa ukugqoka ngezigaba ezahlukene ihlukile. Isb:
Phakathi nenqubo yokugcina, kuyinto efiselekayo ukuba ne-viscosity ephezulu ukuvimbela i-pigment ekuxazululeni;
Phakathi nenqubo yokwakha, kuyinto efiselekayo ukuba ne-viscosity elinganiselayo ukuze kuqinisekiswe ukuthi upende une-brushability enhle ngaphandle kokugcoba ngopende ngokweqile;
Ngemuva kokwakhiwa, kuthenjwa ukuthi i-viscosity ingabuyela ngokushesha ku-viscosity ephezulu ngemuva kwesikhashana esifushane (inqubo yokulinganisa) ukuvimbela ukuwohloka.
I-fluidity ye-coatings yamanzi ayiyona i-Newtonian.
Lapho i-viscosity kapende iyancipha ngokunyuka kwamandla e-shear, ibizwa ngokuthi i-pseudoplastic fluid, futhi iningi lopende liyi-pseudoplastic fluid.
Lapho ukuziphatha kokugeleza kwe-pseudoplastic fluid kuhlobene nomlando wayo, okungukuthi, kuncike esikhathini, kubizwa ngokuthi i-thixotropic fluid.
Lapho sikhiqiza ama-coatings, sivame ukuzama ngokuqaphela ukwenza izigqoko zibe thixotropic, njengokwengeza izithasiselo.
Lapho i-thixotropy ye-coating ifanelekile, ingaxazulula ukuphikisana kwezigaba ezihlukahlukene zokugqoka, futhi ihlangabezane nezidingo zobuchwepheshe ze-viscosity ehlukene yokugqoka endaweni yokugcina, ukulinganisa ukwakhiwa, nezigaba zokomisa.
Amanye ama-thickeners angakwazi ukunikeza upende nge-thixotropy ephezulu, ukuze ibe ne-viscosity ephakeme ekuphumuleni noma ngenani eliphansi le-shear (njengesitoreji noma ukuthutha), ukuze kuvinjwe i-pigment kupende ukuthi ingahlali. Futhi ngaphansi kwesilinganiso esiphezulu se-shear (njengenqubo yokugqoka), ine-viscosity ephansi, ukuze ukugqoka kube nokugeleza okwanele nokulinganisa.
Thixotropy imelelwa inkomba ye-thixotropic TI futhi ikalwa nge-viscometer ye-Brookfield.
I-TI=i-viscosity ( ikalwa ku-6r/min)/i-viscosity ( ikalwa ngo-60r/min)
2. Izinhlobo zama-thickeners kanye nemiphumela yazo ezintweni zokugqoka
(1) Izinhlobo Ngokokwakheka kwamakhemikhali, ama-thickeners ahlukaniswe abe izigaba ezimbili: i-organic kanye ne-inorganic.
Izinhlobo ze-inorganic zihlanganisa i-bentonite, i-attapulgite, i-aluminium magnesium silicate, i-lithium magnesium silicate, njll., izinhlobo eziphilayo ezifana ne-methyl cellulose, i-hydroxyethyl cellulose, i-polyacrylate, i-polymethacrylate, i-acrylic acid noma i-methyl Acrylic homopolymer noma i-copolymer ne-polyurethane njll.
Ngokombono wethonya kuzakhiwo ze-rheological ze-coatings, ama-thickeners ahlukaniswe abe ama-thickeners e-thixotropic kanye nama-thickeners associative. Ngokwezidingo zokusebenza, inani le-thickener kufanele libe lincane futhi umphumela wokujiya ube muhle; akulula ukuguguleka ngama-enzyme; lapho izinga lokushisa noma inani le-pH lesistimu lishintsha, i-viscosity ye-coating ngeke incishiswe kakhulu, futhi i-pigment ne-filler ngeke ihanjiswe. ; Ukuzinza okuhle kwesitoreji; ukugcinwa kahle kwamanzi, akukho mkhuba osobala onamagwebu futhi akukho miphumela emibi ekusebenzeni kwefilimu yokumboza.
①I-cellulose thickener
Ama-cellulose thickeners asetshenziswa embotsheni ikakhulukazi i-methylcellulose, i-hydroxyethylcellulose ne-hydroxypropylmethylcellulose, kanti lezi ezimbili zokugcina zisetshenziswa kakhulu.
I-Hydroxyethyl cellulose iwumkhiqizo otholwe ngokushintsha amaqembu e-hydroxyl kumayunithi eglucose we-cellulose yemvelo ngamaqembu e-hydroxyethyl. Ukucaciswa namamodeli wemikhiqizo ahlukaniswa ngokuyinhloko ngokwezinga lokushintshwa kanye ne-viscosity.
Izinhlobo ze-hydroxyethyl cellulose nazo zihlukaniswe ngohlobo olujwayelekile lokuhlakazeka, uhlobo lokuhlakazeka okusheshayo kanye nohlobo lokuzinza kwebhayoloji. Ngokuphathelene nendlela yokusetshenziswa, i-hydroxyethyl cellulose ingangezwa ngezigaba ezihlukene enqubweni yokukhiqiza yokumboza. Uhlobo oluhlakazeka ngokushesha lungangezwa ngokuqondile ngesimo sempushana eyomile. Kodwa-ke, inani le-pH yesistimu ngaphambi kokwengeza kufanele libe ngaphansi kuka-7, ikakhulukazi ngenxa yokuthi i-hydroxyethyl cellulose incibilika kancane ngenani le-pH eliphansi, futhi kuba nesikhathi esanele sokuthi amanzi angene ngaphakathi kwezinhlayiya, bese inani le-pH liyenyuka ukuze Incibilike ngokushesha. Izinyathelo ezihambisanayo zingasetshenziswa futhi ukulungisa ukuhlushwa okuthile kwesisombululo seglue bese uyengeza ohlelweni lokugqoka.
I-Hydroxypropyl methylcelluloseumkhiqizo otholwe ngokufaka iqembu le-hydroxyl esikhundleni seqembu le-glucose ye-cellulose yemvelo ngeqembu le-methoxy, kuyilapho enye ingxenye ithathelwa indawo yiqembu le-hydroxypropyl. Umphumela wayo wokujiya ngokuyisisekelo uyafana nowe-hydroxyethyl cellulose. Futhi imelana nokuwohloka kwe-enzymatic, kodwa ukuncibilika kwayo emanzini akufani naleyo ye-hydroxyethyl cellulose, futhi inobubi be-gelling lapho ishiswa. Okwe-hydroxypropyl methylcellulose ephathwe phezulu, ingangezwa ngqo emanzini uma isetshenziswa. Ngemva kokuhlanganisa nokuhlakaza, engeza izinto ezine-alkaline ezifana namanzi e-ammonia ukuze ulungise inani le-pH libe ngu-8-9, bese ugoqoza uze uncibilike ngokuphelele. Nge-hydroxypropyl methylcellulose ngaphandle kokwelashwa okungaphezulu, ingacwiliswa futhi ivuvukele ngamanzi ashisayo angaphezu kuka-85 ° C ngaphambi kokusetshenziswa, bese ipholiswa ekamelweni lokushisa, bese ixutshwa ngamanzi abandayo noma amanzi e-ice ukuze incibilike ngokugcwele.
②I-thickener ye-Inorganic
Lolu hlobo lwe-thickener ngokuyinhloko luyimikhiqizo ethile yobumba ecushiwe, njenge-bentonite, i-magnesium aluminium silicate ubumba, njll. Ibonakala ngokuthi ngaphezu komphumela wokuqina, ibuye ibe nomphumela omuhle wokumisa, ingavimbela ukucwiliswa, futhi ngeke ithinte ukumelana kwamanzi kwe-coating. Ngemuva kokuba i-coating isomile futhi yenziwe ifilimu, yenza njenge-filler kwifilimu yokugqoka, njll. Isici esingathandeki ukuthi sizothinta kakhulu ukulinganisa kokugqoka.
③ I-synthetic polymer thickener
Ama-synthetic polymer thickeners asetshenziswa kakhulu ku-acrylic ne-polyurethane (ama-associative thickeners). Ama-thickeners e-Acrylic ngokuvamile ama-polymer e-acrylic aqukethe amaqembu e-carboxyl. Emanzini anenani le-pH lika-8-10, iqembu le-carboxyl liyahlukana futhi livuvukale; lapho inani le-pH likhulu kuno-10, lincibilika emanzini futhi lilahlekelwa umphumela wokujiya, ngakho umphumela wokujiya uzwela kakhulu kunani le-pH.
Indlela yokuqina ye-acrylate thickener iwukuthi izinhlayiya zayo zingakhangiswa ebusweni bezinhlayiya ze-latex kupende, futhi zakhe ungqimba olunamathelayo ngemva kokuvuvukala kwe-alkali, okwandisa umthamo wezinhlayiya ze-latex, kuvimbele ukunyakaza kwe-Brownian kwezinhlayiya, futhi kwandise i-viscosity yesistimu kapende. ; Okwesibili, ukuvuvukala kwe-thickener kwandisa i-viscosity yesigaba samanzi.
(2) Ithonya le-thickener ezindaweni zokumboza
Umphumela wohlobo lwe-thickener kuzakhiwo ze-rheological zokugqoka imi kanje:
Uma inani lokujiya likhuphuka, i-viscosity emile yopende ikhula kakhulu, futhi umkhuba wokushintsha i-viscosity uyavumelana ngokuyisisekelo uma ungaphansi kwamandla okugunda angaphandle.
Ngomphumela we-thickener, i-viscosity kapende yehla ngokushesha lapho ingaphansi kwamandla okugunda, okubonisa i-pseudoplasticity.
Usebenzisa i-hydrophobically modified cellulose thickener (efana ne-EBS451FQ), ngamanani aphezulu okugunda, i-viscosity isephezulu uma inani likhulu.
Ukusebenzisa i-associative polyurethane thickeners (njenge-WT105A), emazingeni aphezulu okugunda, i-viscosity isephezulu uma inani likhulu.
Ukusebenzisa ama-acrylic thickeners (afana ne-ASE60), nakuba i-viscosity emile ikhuphuka ngokushesha uma inani likhulu, i-viscosity iyancipha ngokushesha ngezinga eliphakeme lokugunda.
3. I-Associative thickener
(1) indlela yokuqina
I-cellulose ether kanye ne-alkali-swellable acrylic thickeners ingakwazi ukuqinisa isigaba samanzi kuphela, kodwa ayinayo umphumela wokuqina kwezinye izingxenye kupende osekelwe emanzini, futhi ayikwazi ukubangela ukuxhumana okuphawulekayo phakathi kwe-pigments kupende kanye nezinhlayiya ze-emulsion, ngakho I-rheology yopende ayikwazi ukulungiswa.
Ama-thickeners associative abonakala ngokuthi ngaphezu kokuqina nge-hydration, aphinde ashube ngokusebenzisa izinhlangano phakathi kwawo, nezinhlayiya ezihlakazekile, kanye nezinye izakhi ohlelweni. Le nhlangano ihlukanisa ngamanani aphezulu we-shear futhi iphinde ihlobanise ngamanani aphansi okugunda, okuvumela ukuthi i-rheology ye-coating ilungiswe.
Indlela yokuqina ye-associative thickener ukuthi i-molecule yayo iyiketanga le-hydrophilic eliqondile, inhlanganisela ye-polymer enamaqembu e-lipophilic emikhawulweni yomibili, okungukuthi, inamaqembu e-hydrophilic kanye ne-hydrophobic esakhiweni, ngakho-ke inezici zama-molecule e-surfactant. imvelo. Ama-athomu anjalo anamandla awakwazi nje ukufaka amanzi futhi akhukhumale ukuze ajiye isigaba samanzi, kodwa futhi enze ama-micelles lapho ukugxila kwesisombululo sawo esinamanzi kudlula inani elithile. Ama-micelles angakwazi ukuhlotshaniswa nezinhlayiya ze-polymer ze-emulsion kanye nezinhlayiya ze-pigment eziye zakhangisa i-disperant ukuze zenze isakhiwo senethiwekhi esinezinhlangothi ezintathu, futhi zixhumeke futhi ziboshwe ukuze kwandiswe i-viscosity yesistimu.
Okubaluleke kakhulu ukuthi lezi zinhlangano zisesimweni sokulinganisela okuguquguqukayo, futhi lawo ma-micelles ahlobene angalungisa izindawo zawo lapho engaphansi kwamandla angaphandle, ukuze ukumboza kube nezindawo zokulinganisa. Ngaphezu kwalokho, njengoba i-molecule inama-micelles amaningana, lesi sakhiwo sinciphisa ukuthambekela kwama-molecule wamanzi ukufuduka futhi ngaleyo ndlela kwandisa i-viscosity yesigaba samanzi.
(2) Indima yezingubo ezinengilazi
Iningi lama-associative thickeners ama-polyurethanes, futhi izisindo zawo zamangqamuzana ahlobene ziphakathi kwama-oda angu-103-104 obukhulu, ama-oda amabili obukhulu aphansi kune-polyacrylic acid evamile kanye nama-cellulose thickeners anesisindo samangqamuzana aphakathi kuka-105-106. Ngenxa yesisindo esiphansi samangqamuzana, ukukhuphuka kwevolumu okusebenzayo ngemuva kwe-hydration kuncane, ngakho-ke ijika layo le-viscosity liyisicaba kunalelo lama-thickeners angewona ama-associative.
Ngenxa yesisindo esiphansi samangqamuzana e-associative thickener, ukuboshwa kwayo kwe-intermolecular esigabeni samanzi kunqunyelwe, ngakho-ke umphumela wayo wokuqina esigabeni samanzi awubalulekile. Ezingeni eliphansi lesilinganiso se-shear, ukuguqulwa kwenhlangano phakathi kwama-molecule kungaphezu kokubhujiswa kwenhlangano phakathi kwama-molecule, lonke uhlelo lugcina isimo esingokwemvelo sokumiswa nokuhlakazeka, futhi i-viscosity iseduze ne-viscosity ye-dispersion medium (amanzi). Ngakho-ke, i-associative thickener yenza uhlelo lokupenda olusekelwe emanzini lubonise i-viscosity ephansi ebonakalayo uma isendaweni yezinga eliphansi le-shear.
Ama-thickeners associative andisa amandla angaba khona phakathi kwama-molecule ngenxa yokuhlangana phakathi kwezinhlayiya ezisesigabeni esihlakazekile. Ngale ndlela, amandla engeziwe ayadingeka ukuze kuqedwe ubudlelwane phakathi kwama-molecule emazingeni aphezulu okugunda, futhi amandla okugunda adingekayo ukuze kuzuzwe uhlobo olufanayo lokugunda nawo makhulu, ukuze uhlelo lubonise izinga eliphezulu lokugunda emazingeni aphezulu okugunda. I-viscosity ebonakalayo. I-viscosity ephezulu ye-shear ephezulu kanye ne-viscosity ephansi ye-shear ephansi ingenza nje ukungabi khona kwama-thickeners avamile ezindaweni ze-rheological zopende, okungukuthi, ama-thickeners amabili angasetshenziswa ngokuhlanganisa ukulungisa u-fluidity wepende ye-latex. Ukusebenza okuguquguqukayo, ukuze kuhlangatshezwane nezidingo ezibanzi zokumboza ifilimu ewugqinsi nokugeleza kwefilimu enamathelayo.
Isikhathi sokuthumela: Apr-28-2024