Isebenza kanjani i-HPMC coating dispersant?

1. Isingeniso

IHydroxypropyl Methylcellulose (HPMC) iyi-polymer encibilika emanzini esetshenziswa kabanzi ekwembathweni, ezintweni zokwakha, kwezemithi neminye imikhakha. Embonini yokuhlanganisa, i-HPMC ayisetshenziswa nje kuphela njenge-thickener, stabilizer kanye nefilimu yangaphambili, kodwa futhi njenge-dispersant esebenza kahle kakhulu. Imisebenzi yayo eyinhloko ekugqokeni ihlanganisa ukuthuthukisa ukuzinza kwezingubo, ukuthuthukisa i-rheology, ukuthuthukisa ukusebenza kokwakhiwa kanye nekhwalithi yokugqoka kokugcina.

2. Izici zesakhiwo se-HPMC

Isakhiwo samangqamuzana e-HPMC siqukethe i-cellulose skeleton kanye ne-hydroxypropyl kanye ne-methyl substituents. Isakhiwo sayo esikhethekile sinikeza i-HPMC ukuncibilika emanzini kanye nekhono lokwenza isixazululo se-viscoelastic kusixazululo esinamanzi. I-HPMC isebenzisana nama-athomu ezincibilikayo ngokusebenzisa i-hydrogen bonding namandla e-van der Waals, ngaleyo ndlela incibilike emanzini futhi yakhe uhlelo lokuhlakazeka oluzinzile.

Isisindo se-molecular and degree of substitution (DS) ye-HPMC ithinta ukunyibilika kwayo kanye ne-viscosity. Ngokuvamile, isisindo esiphezulu samangqamuzana kanye nezinga lokushintshwa kwandisa i-viscosity nesikhathi sokuqedwa kwe-HPMC. Lezi zici zibalulekile emsebenzini we-HPMC njengesisabalalisi esinamathelayo.

3. Iqhaza le-HPMC ekufakweni kwezingubo

3.1 Ukwenza ngcono ukuhlakazeka kombala

I-HPMC isetshenziswa kakhulu ukwenza ngcono ukuhlakazeka kwezingulube ezimpahleni. Enkambweni yokukhiqiza yokugqoka, i-agglomeration yezinhlayiya ze-pigment kuyinkinga evamile, okuholela ekugqokeni okungalingani futhi okungazinzile, okuthinta ukucwebezela kanye nokufana kombala kokugqoka. Abasabalalisi be-HPMC badlala indima kulezi zici ezilandelayo:

I-Electrostatic repulsion: Isixazululo esakhiwe yi-HPMC encibilika emanzini sinomsebenzi ongaphezulu futhi singakhangiswa phezu kwezinhlayiya ze-pigment ukuze zishajwe. Lokhu repulsion electrostatic ehlukanisa izinhlayiya sombala komunye nomunye futhi kunciphisa agglomeration.

Umthelela wesithiyo esiqinile: Iketango le-polymer le-HPMC lingenza ungqimba oluvikelayo ebusweni bezinhlayiya ze-pigment, likhulise ibanga lendawo phakathi kwezinhlayiya, futhi ngaleyo ndlela livimbele ukukhangana nokuhlangana phakathi kwezinhlayiya.

Umphumela wokuzinzisa: I-HPMC ihlanganisa nama-molecule amanzi ngokusebenzisa ibhondi ye-hydrogen ukuze yakhe uhlelo oluzinzile lwesisombululo, ivimbele izinhlayiya ze-pigment ukuthi zingahlali ohlelweni, futhi ithuthukise ukuzinza kwento enamathelayo.

3.2 Ukuthuthukisa i-rheology

Omunye umsebenzi obalulekile we-HPMC ukuthuthukisa i-rheology yezingubo, okungukuthi, ukugeleza kanye nezici zokuguqulwa kwezingubo. Izakhiwo ezinhle ze-rheological zokugqoka zisiza ukuba zibe nokusabalala okuhle nokulinganisa ngesikhathi senqubo yokwakha, ukwakha ifilimu yokugqoka iyunifomu. I-HPMC ithinta izakhiwo ze-rheological ze-coating ngokusebenzisa izindlela ezilandelayo:

Ukuthuthukiswa kwe-Viscoelasticity: Isakhiwo senethiwekhi ye-polymer chain esakhiwe yi-HPMC emanzini sinikeza isisombululo i-viscoelasticity ethile. Le viscoelasticity ingalungisa ukugeleza kokugqoka, ukuze ibe ne-viscosity efanele lapho ixubha, inciphisa ukugoqa kanye nokuconsa.

I-Shear thinning: Izixazululo ze-HPMC zivame ukukhombisa izakhiwo zokugunda i-shear, okungukuthi, zine-viscosity ephezulu ngamazinga aphansi okugunda kanye ne-viscosity ephansi ngamanani aphezulu okugunda. Lesi sakhiwo senza i-coating ibe nokuzinza okungcono esimweni esimile futhi kulula ukusabalala ngesikhathi sokwakhiwa.

Thixotropy: Ezinye izixazululo ze-HPMC nazo zibonisa i-thixotropy, okungukuthi, i-viscosity ibuyiselwa ekuphumuleni, okubaluleke kakhulu ekunciphiseni ukugoqa nokudonsa kwe-coating.

3.3 Ukwenza ngcono ukusebenza kwe-coating

I-HPMC ayinayo kuphela ithonya elibalulekile ekusebenzeni kwe-coating ngesikhathi sokwakhiwa, kodwa futhi ithuthukisa kakhulu ikhwalithi yokugqoka kokugcina. I-HPMC ithuthukisa ukusebenza kwezingubo kulezi zici ezilandelayo:

I-Coating flatness: I-HPMC ithuthukisa i-rheology ye-coating, ithuthukisa ukusabalala nokulinganisa kwe-coating, futhi yenza ukunamathela kube bushelelezi futhi kufane kakhulu.

Ukumelana namanzi nokumelana nesimo sezulu: I-HPMC yakha isakhiwo senethiwekhi esiminyene embotsheni, okwandisa ukumelana namanzi kanye nekhono lokulwa nokuguga lokumboza, futhi kuthuthukise ukumelana nesimo sezulu sokumboza.

Ukunamathela: I-HPMC ithuthukisa ukunamathela kokugqoka, ukuze ukugqoka kuhlanganiswe ngokuqinile ebusweni be-substrate, futhi kuthuthukise ukuqina kokugqoka.

4. Izibonelo zohlelo lokusebenza lwe-HPMC

4.1 Izembatho zezakhiwo

Ezingxenyeni zezakhiwo, i-HPMC isetshenziselwa ukuthuthukisa ukuhlakazwa kwezingulube kanye ne-rheology yezingubo zokugqoka, ikakhulukazi zokugqoka ezisekelwe emanzini. I-HPMC ithuthukisa ukuzinza nokusebenza kokwakhiwa kwe-coating, ukuze okunamathelayo kube nokulingana okungcono nokunamathela odongeni, futhi kuvimbele ifilimu ukuthi ingagxumeki futhi ingalingani.

4.2 Izingubo zezimboni

I-HPMC iphinde isetshenziswe kabanzi ekuhlanganisweni kwezimboni. Akugcini nje ukuthuthukisa i-dispersibility ye-pigments, kodwa futhi kuthuthukisa ukusebenza kokwakhiwa kwezingubo, okwenza ifilimu yokugqoka inamathele kakhulu ensimbi, epulasitiki kanye namanye ama-substrates, kanye nefilimu ehlanganisiwe eyakhiwe ihlale isikhathi eside.

4.3 Amanye ama-coatings

I-HPMC iphinde isetshenziswe ezinhlobonhlobo ezihlukahlukene ezikhethekile, njengezingubo ezivimbela umlilo, izigqoko zokulwa nokugqwala, njll. Indima yayo kulezi zingubo ngokuyinhloko ukuthuthukisa ukuzinza kwezingubo kanye nokusebenza kwefilimu yokugqoka, ukuze izigqoko zibe nokusebenza okuhle izindawo ezihlukahlukene eziyinkimbinkimbi.

Njenge-dispersant enamathelayo, i-HPMC idlala indima ebalulekile ekuthuthukiseni ukuhlakazeka kwezingulube, ukuthuthukisa i-rheology yezingubo kanye nokwenza ngcono ukusebenza kwamafilimu okugcoba. Isakhiwo sayo esiyingqayizivele kanye nomsebenzi kunikeza amathuba amaningi okusebenzisa embonini yokugqoka. Ngokuthuthukiswa kobuchwepheshe bokuhlanganisa, ukusetshenziswa kwe-HPMC kuzoqhubeka nokukhula, kunikeze amathuba amaningi okuthuthukisa kanye nokuqanjwa kokusebenza kokugqoka.