Focus on Cellulose ethers

Izikhuthazi zikapende ezisekelwe emanzini

1. Izinhlobo zama-thickeners kanye nendlela yokuqina

(1) I-Inorganic thickener:

Ama-thickeners we-Inorganic kumasistimu asekelwe emanzini ikakhulukazi ubumba. Njenge: bentonite. I-Kaolin kanye nomhlaba we-diatomaceous (ingxenye eyinhloko i-SiO2, enesakhiwo esinezimbotshana) ngezinye izikhathi zisetshenziswa njengezingqimba ezisizayo zezinhlelo zokujiya ngenxa yezakhiwo zazo zokulengiswa. I-Bentonite isetshenziswa kabanzi ngenxa yokuvuvukala kwayo okuphezulu kwamanzi. I-Bentonite (i-Bentonite), eyaziwa nangokuthi i-bentonite, i-bentonite, njll., i-mineral eyinhloko ye-bentonite i-montmorillonite equkethe inani elincane le-alkali kanye ne-alkaline yomhlaba yensimbi ye-hydrous aluminosilicate amaminerali, okuyingxenye yeqembu le-aluminosilicate, ifomula yayo yamakhemikhali jikelele yile: (Na ,Ca)(Al,Mg)6(Si4O10)3(OH)6•nH2O. Ukusebenza kokunwetshwa kwe-bentonite kuvezwa amandla okunweba, okungukuthi, umthamo we-bentonite ngemuva kokuvuvukala ku-dilute hydrochloric acid solution ubizwa ngokuthi umthamo wokukhulisa, ovezwe ku-ml/gram. Ngemuva kokuthi i-bentonite thickener idonsa amanzi futhi ivuvuke, ivolumu ingafinyelela izikhathi eziningana noma izikhathi eziyishumi ngaphambi kokumunca amanzi, ngakho-ke inokumiswa okuhle, futhi ngenxa yokuthi i-powder enobukhulu bezinhlayiyana ezincane, ihluke kwezinye izimpushana ekugqokeni. uhlelo. Umzimba unokuxubene kahle. Ngaphezu kwalokho, ngenkathi ikhiqiza ukumiswa, ingakwazi ukushayela amanye ama-powders ukukhiqiza umphumela othile wokulwa ne-stratification, ngakho-ke kuyasiza kakhulu ukuthuthukisa ukuzinza kwesitoreji sesistimu.

Kodwa ama-bentonite amaningi asekelwe kwi-sodium aguqulwa esuka ku-calcium-based bentonite ngokusebenzisa ukuguqulwa kwe-sodium. Ngesikhathi esifanayo se-sodiumization, inani elikhulu lama-ion amahle njenge-calcium ions kanye ne-sodium ion lizokhiqizwa. Uma okuqukethwe kwalawa ma-cations ohlelweni kuphezulu kakhulu, inani elikhulu le-neutralization yenkokhelo lizokhiqizwa ngamashaji angalungile ebusweni be-emulsion, ngakho-ke ngezinga elithile, Kungase kubangele imiphumela emibi njengokuvuvukala nokugeleza kwe-flocculation. i-emulsion. Ngakolunye uhlangothi, lezi ion ze-calcium zizophinde zibe nemiphumela emibi ku-sodium salt dispersant (noma i-polyphosphate dispersant), okubangela ukuthi lezi zihlakazezi ziphuze ohlelweni lokumboza, ekugcineni kuholele ekulahlekeni kokuhlakazeka, okwenza ukunamathela kube kukhulu, kukhulu noma ngisho. mkhulu. Kwenzeke imvula enamandla kanye ne-flocculation. Ukwengeza, umphumela wokuqina we-bentonite ngokuyinhloko uncike ku-powder ukuze ubambe amanzi futhi wandise ukuze ukhiqize ukumiswa, ngakho-ke uzoletha umphumela oqinile we-thixotropic ohlelweni lokumboza, okungekuhle kakhulu kwezingubo ezidinga imiphumela emihle yokulinganisa. Ngakho-ke, ama-thickeners we-bentonite angavamile ukusetshenziswa kumapende e-latex, futhi inani elincane kuphela elisetshenziswa njengama-thickeners kumapende we-latex wezinga eliphansi noma amapende we-latex axutshwe. Nokho, eminyakeni yakamuva, enye idatha ibonise ukuthi i-BENTONE®LT ka-Hemmings. i-organically modified and refined i-hectorite inemiphumela emihle yokulwa ne-sedimentation kanye ne-atomization uma isetshenziswa kumasistimu wokufafaza angenawo umoya wopende we-latex.

(2) I-cellulose ether:

I-Cellulose ether i-polymer ephezulu yemvelo eyakhiwe ukufingqa kwe-β-glucose. Ngokusebenzisa izici zeqembu le-hydroxyl eringini ye-glucosyl, i-cellulose ingabhekana nokusabela okuhlukahlukene ukuze ikhiqize uchungechunge lokuphuma kokunye. Phakathi kwazo, ukusabela kwe-esterification kanye ne-etherification kuyatholakala. I-cellulose ester noma okuphuma kwe-cellulose ether yizinto eziphuma ku-cellulose ezibaluleke kakhulu. Imikhiqizo esetshenziswa kakhulu i-carboxymethyl cellulose,i-hydroxyethyl cellulose, i-methyl cellulose, i-hydroxypropyl methyl cellulose nokunye. Ngenxa yokuthi i-carboxymethyl cellulose iqukethe ama-ion e-sodium ancibilika kalula emanzini, ayinawo amandla okumelana namanzi, futhi inani lezinto ezifakwa esikhundleni seketango layo elikhulu lincane, ngakho-ke ibola kalula ngokugqwala kwamagciwane, inciphisa i-viscosity yesisombululo samanzi futhi isenze elinuka, njll. Isimanga, esingavamile ukusetshenziswa kupende we-latex, ngokuvamile osetshenziswa kupende weglue we-polyvinyl utshwala wezinga eliphansi kanye ne-putty. Izinga lokuchithwa kwamanzi le-methylcellulose ngokuvamile liphansi kancane kune-hydroxyethylcellulose. Ukwengeza, kungase kube nenani elincane lezinto ezingancibiliki ngesikhathi senqubo yokuchithwa, okuzothinta ukubukeka nokuzwakala kwefilimu yokugqoka, ngakho-ke akuvamile ukusetshenziselwa upende we-latex. Kodwa-ke, ukungezwani okungaphezulu kwesisombululo se-methyl aqueous kungaphansi kancane kunezinye izixazululo ezinamanzi e-cellulose, ngakho-ke i-cellulose thickener enhle esetshenziswa ku-putty. IHydroxypropyl methylcellulose iphinde ibe yi-cellulose thickener esetshenziswa kabanzi emkhakheni we-putty, futhi manje isisetshenziswa kakhulu kusimende-based noma i-lime-calcium-based putty (noma ezinye izibophezelo ze-inorganic). I-Hydroxyethyl cellulose isetshenziswa kakhulu ezinhlelweni zokupenda ze-latex ngenxa yokuncibilika kwayo okuhle kwamanzi kanye nokugcinwa kwamanzi. Uma kuqhathaniswa namanye ama-cellulose, inomphumela omncane ekusebenzeni kwefilimu yokugqoka. Izinzuzo ze-hydroxyethyl cellulose zihlanganisa ukusebenza kahle kokumpompa okuphezulu, ukuhambisana okuhle, ukugcinwa okuhle kokugcinwa kokuqina, nokuzinza okuhle kwe-pH ye-viscosity. Okubi wukungalawuleki kahle kwezinga kanye nokungazweli kahle kwe-splash. Ukuze kuthuthukiswe lezi ziphutha, ukuguqulwa kwe-hydrophobic kuvele. I-hydroxyethylcellulose (HMHEC) ehlobene nocansi njenge-NatrosolPlus330, 331

(3) Ama-Polycarboxylates:

Kule polycarboxylate, isisindo esiphezulu samangqamuzana siwugqinsi, futhi isisindo esiphansi samangqamuzana si-dispersant. Ngokuyinhloko bakhangisa ama-molecule amanzi ochungechungeni oluyinhloko lwesistimu, okwandisa i-viscosity yesigaba esihlakazekile; ngaphezu kwalokho, zingase futhi zikhangiswe ebusweni bezinhlayiya ze-latex ukuze zenze ungqimba olunamathelayo, okwandisa usayizi wezinhlayiyana ze-latex, kuqinisa ungqimba lwe-hydration ye-latex, futhi kwandisa i-viscosity yesigaba sangaphakathi se-latex. Kodwa-ke, lolu hlobo lwe-thickener lusebenza kahle kakhulu, ngakho-ke luyaqedwa kancane kancane ekusetshenzisweni kokugqoka. Manje lolu hlobo lwe-thickener lusetshenziswa ngokuyinhloko ekuqinisweni kokunamathisela kombala, ngoba isisindo salo samangqamuzana sikhulu, ngakho-ke kuyasiza ekuhlakazeni nasekugcineni ukuzinza kokunamathisela kombala.

(4) I-alkali-swellable thickener:

Kunezinhlobo ezimbili eziyinhloko zama-alkali-swellable thickeners: ama-alkali-swellable thickeners ajwayelekile kanye nama-alkali-swellable thickeners associative. Umehluko omkhulu phakathi kwabo umehluko kuma-monomers ahlotshaniswayo aqukethwe ochungechungeni oluyinhloko lwamangqamuzana. Ama-thickeners associative alkali-swellable thickeners ahlanganiswe nama-associative monomers angakhangisana esakhiweni seketango eliyinhloko, ngakho-ke ngemva kwe-ionization esixazululweni samanzi, ukukhangisa kwe-intra-molecular noma inter-molecular kungenzeka, okubangela ukuthi i-viscosity yesistimu ikhuphuke ngokushesha.

a. I-thickener evamile ye-alkali-swellable:

Uhlobo oluyinhloko olumele umkhiqizo lwe-alkali-swellable thickener evamile yi-ASE-60. I-ASE-60 yamukela ikakhulukazi i-copolymerization ye-methacrylic acid ne-ethyl acrylate. Ngesikhathi senqubo ye-copolymerization, i-methacrylic acid ilandisa cishe nge-1/3 yokuqukethwe okuqinile, ngoba ukuba khona kwamaqembu e-carboxyl kwenza uchungechunge lwamangqamuzana lube nezinga elithile le-hydrophilicity, futhi lwenza kube lula inqubo yokwenza usawoti. Ngenxa yokwehliswa kwamacala, amaketanga e-molecular anwetshwa, okwandisa i-viscosity yesistimu futhi akhiqize umphumela wokuqina. Nokho, ngezinye izikhathi isisindo samangqamuzana sikhulu kakhulu ngenxa yesenzo se-agent yokuxhumanisa. Phakathi nenqubo yokwandisa uchungechunge lwamangqamuzana, iketanga lamangqamuzana alihlakazeka kahle ngesikhathi esifushane. Phakathi nenqubo yokugcina isikhathi eside, uchungechunge lwamangqamuzana lunwetshwa kancane kancane, okuletha i-Post-thickening of viscosity. Ngaphezu kwalokho, ngenxa yokuthi kukhona ama-hydrophobic monomers ambalwa ochungechungeni lwamangqamuzana alolu hlobo lwe-thickener, akulula ukukhiqiza ukuhlanganiswa kwe-hydrophobic phakathi kwama-molecule, ikakhulukazi ukwenza i-intramolecular mutual adsorption, ngakho-ke lolu hlobo lokuqina lunokusebenza okuphansi kokuqina, ngakho-ke akuvamile ukusetshenziswa yedwa. Isetshenziswa kakhulu ngokuhlangana namanye ama-thickeners.

b. I-Association (concord) uhlobo lwe-alkali thickener yokuvuvukala:

Lolu hlobo lwe-thickener manje lunezinhlobonhlobo eziningi ngenxa yokukhethwa kwama-monomers ahlangene kanye nomklamo wesakhiwo samangqamuzana. Isakhiwo sayo seketango eliyinhloko siphinde sakhiwe ikakhulukazi i-methacrylic acid ne-ethyl acrylate, futhi ama-monomers ahlangene afana nezimpondo esakhiweni, kodwa inani elincane lokusabalalisa. Yilawa ma-monomers ahlanganayo afana namathenda e-octopus adlala indima ebaluleke kakhulu ekusebenzeni kahle kokuqina kwe-thickener. Iqembu le-carboxyl esakhiweni alithathi hlangothi futhi lenza usawoti, futhi iketango lamangqamuzana lifana ne-alkali-swellable thickener evamile. I-charge repulsion efanayo iyenzeka, ukuze uchungechunge lwamangqamuzana luvuleleke. I-associative monomer kuyo iphinde ikhule ngeketanga lamangqamuzana, kodwa isakhiwo sayo siqukethe kokubili amaketanga e-hydrophilic namaketanga e-hydrophobic, ngakho-ke isakhiwo esikhulu se-micellar esifana nama-surfactants sizokhiqizwa ku-molecule noma phakathi kwama-molecule. Lawa ma-micelles akhiqizwa i-mutual adsorption ye-association monomers, futhi amanye ama-monomers enhlangano akhangisana ngomthelela wokuvala wezinhlayiya ze-emulsion (noma ezinye izinhlayiya). Ngemuva kokuthi ama-micelles akhiqiziwe, alungisa izinhlayiya ze-emulsion, izinhlayiya ze-molecule yamanzi noma ezinye izinhlayiya ohlelweni esimweni esilinganiselwe njengokunyakaza kwe-enclosure, ukuze ukuhamba kwalawa ma-molecule (noma izinhlayiya) kube buthaka kanye ne-viscosity ye ukwanda kohlelo. Ngakho-ke, ukusebenza kahle kokuqina kwalolu hlobo lwe-thickener, ikakhulukazi kupende we-latex onokuqukethwe okuphezulu kwe-emulsion, kuphakeme kakhulu kunokwama-alkali-swellable thickeners ajwayelekile, ngakho-ke isetshenziswa kakhulu kupende we-latex. Ummeleli womkhiqizo oyinhloko Uhlobo luyi-TT-935.

(5) I-Associative polyurethane (noma i-polyether) i-agent yokuqina neyokulinganisa:

Ngokuvamile, ama-thickeners anesisindo esikhulu samangqamuzana (njenge-cellulose ne-acrylic acid), futhi amaketanga awo amangqamuzana anwetshiwe kusisombululo samanzi ukuze kwandiswe i-viscosity yesistimu. Isisindo samangqamuzana e-polyurethane (noma i-polyether) sincane kakhulu, futhi ikakhulukazi sakha inhlangano ngokusebenzisana kwe-van der Waals force ye-lipophilic segment phakathi kwama-molecule, kodwa le nhlangano ibuthakathaka, futhi inhlangano ingenziwa ngaphansi kwezimo ezithile. amandla angaphandle. Ukuhlukaniswa, ngaleyo ndlela kunciphisa i-viscosity, kuhambisana nokulingana kwefilimu yokugqoka, ngakho-ke ingadlala indima ye-agent yokulinganisa. Lapho amandla e-shear eqedwa, angakwazi ukuqala kabusha ngokushesha ukuhlangana, futhi i-viscosity yesistimu iphakama. Lesi simo sinenzuzo ukunciphisa i-viscosity nokwandisa izinga ngesikhathi sokwakhiwa; futhi ngemva kokulahlekelwa amandla okugunda, i-viscosity izobuyiselwa ngokushesha ukuze kwandiswe ubukhulu befilimu yokugqoka. Ekusetshenzisweni okungokoqobo, sikhathazeke kakhulu ngomthelela wokujiya wezinto ezifana nama-associative thickeners kuma-emulsion we-polymer. Izinhlayiya eziyinhloko ze-polymer latex nazo zibamba iqhaza ekuhlanganiseni kwesistimu, ukuze lolu hlobo lokuqina nokulinganisa i-ejenti lubuye lube nomphumela omuhle wokuqina (noma wokulinganisa) uma luphansi kunokugxila kwalo okubalulekile; lapho ukuhlushwa kwalolu hlobo lwe-ejenti yokuqina nokulinganisa Uma kuphakeme kunokugxila okubalulekile emanzini ahlanzekile, kungenza izinhlangano ngokwazo, futhi i-viscosity ikhuphuka ngokushesha. Ngakho-ke, lapho lolu hlobo lwe-ejenti yokuqina nokulinganisa luphansi kunokugxila kwalo okubalulekile, ngoba izinhlayiya ze-latex zihlanganyela ekuhlanganiseni okuyingxenye, usayizi omncane wezinhlayiyana ze-emulsion, ukuqina kwenhlangano, kanye ne-viscosity yayo izokhula ngokukhula kwe-emulsion. inani le-emulsion. Ngaphezu kwalokho, amanye ama-dispersants (noma ama-acrylic thickeners) aqukethe izakhiwo ze-hydrophobic, futhi amaqembu abo e-hydrophobic asebenzisana nalawo e-polyurethane, ukuze uhlelo ludale isakhiwo esikhulu senethiwekhi, esivumelana nokuqina.

2. Imiphumela yama-thickeners ahlukene ekumelaneni nokuhlukaniswa kwamanzi kopende we-latex

Ekwakheni ukwakheka kwamapende asekelwe emanzini, ukusetshenziswa kwama-thickeners kuyisixhumanisi esibaluleke kakhulu, esihlobene nezakhiwo eziningi zamapende e-latex, njengokwakhiwa, ukuthuthukiswa kombala, ukugcinwa nokubukeka. Lapha sigxila emthelela wokusetshenziswa kwama-thickeners ekugcinweni kopende we-latex. Kusukela esingenisweni esingenhla, singakwazi ukuthi i-bentonite ne-polycarboxylates: ama-thickeners asetshenziswa ikakhulukazi kwezinye izigqoko ezikhethekile, ezingeke zixoxwe lapha. Sizoxoxa ngokuyinhloko nge-cellulose esetshenziswa kakhulu, ukuvuvukala kwe-alkali, kanye ne-Polyurethane (noma i-polyether) ukuqina, iyodwa futhi ihlangene, kuthinta ukumelana nokuhlukaniswa kwamanzi kopende be-latex.

Nakuba ukujiya nge-hydroxyethyl cellulose kukodwa kubi kakhulu ekuhlukaniseni amanzi, kulula ukuyinyakazisa ngokulinganayo. Ukusetshenziswa okukodwa kokuqina kokuvuvukala kwe-alkali akunakho ukwahlukaniswa kwamanzi kanye nemvula kodwa ukujiya okukhulu ngemva kokuqina. Ukusetshenziswa okukodwa kwe-polyurethane thickening, nakuba ukuhlukaniswa kwamanzi kanye nokuqina ngemva kokuqina Ukuqina akubi kakhulu, kodwa imvula ekhiqizwa yiyo inzima futhi kunzima ukuyinyakazisa. Futhi yamukela i-hydroxyethyl cellulose kanye ne-alkali ukuvuvukala kwamakhemikhali, akukho post-thickening, akukho imvula eqinile, kulula ukuyinyakazisa, kodwa kukhona nenani elincane lamanzi. Nokho, lapho kusetshenziswa i-hydroxyethyl cellulose ne-polyurethane ukuze kushube, ukuhlukaniswa kwamanzi yikona okubucayi kakhulu, kodwa akukho mvula eqinile. I-alkali-swellable thickening kanye ne-polyurethane isetshenziswa ndawonye, ​​nakuba ukuhlukaniswa kwamanzi ngokuyisisekelo akukho ukuhlukaniswa kwamanzi, kodwa ngemva kokuqina, futhi i-sediment engezansi kunzima ukuyinyakazisa ngokulinganayo. Futhi owokugcina usebenzisa inani elincane le-hydroxyethyl cellulose enokuvuvukala kwe-alkali kanye nokujiya kwe-polyurethane ukuze ibe nesimo esifanayo ngaphandle kwemvula nokuhlukana kwamanzi. Kungabonakala ukuthi ohlelweni lwe-acrylic emulsion oluhlanzekile olune-hydrophobicity eqinile, kubaluleke kakhulu ukushubisa isigaba samanzi nge-hydrophilic hydroxyethyl cellulose, kodwa ingashukunyiswa kalula ngokulinganayo. Ukusetshenziswa okukodwa kokuvuvukala kwe-alkali ye-hydrophobic kanye ne-polyurethane (noma i-polyurethane) (noma i-compound yabo) ukuqina, nakuba ukusebenza kokuhlukanisa okulwa namanzi kungcono, kodwa kokubili kuyajiya kamuva, futhi uma kunemvula, kubizwa ngokuthi imvula eqinile, okunzima ukuyinyakazisa ngokulinganayo . Ukusetshenziswa kwe-cellulose kanye ne-polyurethane compound thickening, ngenxa yomehluko ode kakhulu kumanani we-hydrophilic kanye ne-lipophilic, kubangela ukuhlukana kwamanzi okubucayi kakhulu kanye nemvula, kodwa i-sediment ithambile futhi kulula ukuyinyakazisa. Ifomula yokugcina inokusebenza okuhle kakhulu kokuhlukaniswa kwamanzi okulwa namanzi ngenxa yebhalansi engcono phakathi kwe-hydrophilic ne-lipophilic. Yiqiniso, enkambweni yangempela yokuklama ifomula, izinhlobo zama-emulsions kanye nama-ejenti wokumanzisa nokuhlakazeka kanye namanani abo e-hydrophilic kanye ne-lipophilic kufanele futhi acatshangelwe. Kuphela lapho befinyelela ibhalansi enhle lapho isistimu ingaba sesimweni sokulingana kwe-thermodynamic futhi ibe nokuphikiswa okuhle kwamanzi.

Kuhlelo lokuqina, ukuqina kwesigaba samanzi kwesinye isikhathi kuhambisana nokwanda kwe-viscosity yesigaba samafutha. Isibonelo, ngokuvamile sikholelwa ukuthi ama-cellulose thickeners ashubisa isigaba samanzi, kodwa i-cellulose isatshalaliswa esigabeni samanzi.


Isikhathi sokuthumela: Dec-29-2022
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